nsz Git - cparser/blob - parser.c

   1 /*
   2  * This file is part of cparser.
   3  * Copyright (C) 2007-2009 Matthias Braun <matze@braunis.de>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18  * 02111-1307, USA.
  19  */
  20 #include <config.h>
  21
  22 #include <assert.h>
  23 #include <ctype.h>
  24 #include <stdarg.h>
  25 #include <stdbool.h>
  26
  27 #include "adt/strutil.h"
  28 #include "parser.h"
  29 #include "diagnostic.h"
  30 #include "format_check.h"
  31 #include "preprocessor.h"
  32 #include "symbol_t.h"
  33 #include "token_t.h"
  34 #include "types.h"
  35 #include "type_t.h"
  36 #include "type_hash.h"
  37 #include "ast_t.h"
  38 #include "entity_t.h"
  39 #include "attribute_t.h"
  40 #include "lang_features.h"
  41 #include "walk.h"
  42 #include "warning.h"
  43 #include "printer.h"
  44 #include "ast2firm.h"
  45 #include "adt/bitfiddle.h"
  46 #include "adt/error.h"
  47 #include "adt/array.h"
  48
  49 //#define PRINT_TOKENS
  50 #define MAX_LOOKAHEAD 1
  51
  52 typedef struct {
  53         entity_t           *old_entity;
  54         symbol_t           *symbol;
  55         entity_namespace_t  namespc;
  56 } stack_entry_t;
  57
  58 typedef struct declaration_specifiers_t  declaration_specifiers_t;
  59 struct declaration_specifiers_t {
  60         source_position_t  source_position;
  61         storage_class_t    storage_class;
  62         unsigned char      alignment;         /**< Alignment, 0 if not set. */
  63         bool               is_inline    : 1;
  64         bool               thread_local : 1;
  65         attribute_t       *attributes;        /**< list of attributes */
  66         type_t            *type;
  67 };
  68
  69 /**
  70  * An environment for parsing initializers (and compound literals).
  71  */
  72 typedef struct parse_initializer_env_t {
  73         type_t     *type;   /**< the type of the initializer. In case of an
  74                                  array type with unspecified size this gets
  75                                  adjusted to the actual size. */
  76         entity_t   *entity; /**< the variable that is initialized if any */
  77         bool        must_be_constant;
  78 } parse_initializer_env_t;
  79
  80 typedef entity_t* (*parsed_declaration_func) (entity_t *declaration, bool is_definition);
  81
  82 /** The current token. */
  83 static token_t              token;
  84 /** The lookahead ring-buffer. */
  85 static token_t              lookahead_buffer[MAX_LOOKAHEAD];
  86 /** Position of the next token in the lookahead buffer. */
  87 static size_t               lookahead_bufpos;
  88 static stack_entry_t       *environment_stack = NULL;
  89 static stack_entry_t       *label_stack       = NULL;
  90 static scope_t             *file_scope        = NULL;
  91 static scope_t             *current_scope     = NULL;
  92 /** Point to the current function declaration if inside a function. */
  93 static function_t          *current_function  = NULL;
  94 static entity_t            *current_entity    = NULL;
  95 static switch_statement_t  *current_switch    = NULL;
  96 static statement_t         *current_loop      = NULL;
  97 static statement_t         *current_parent    = NULL;
  98 static ms_try_statement_t  *current_try       = NULL;
  99 static linkage_kind_t       current_linkage;
 100 static goto_statement_t    *goto_first        = NULL;
 101 static goto_statement_t   **goto_anchor       = NULL;
 102 static label_statement_t   *label_first       = NULL;
 103 static label_statement_t  **label_anchor      = NULL;
 104 /** current translation unit. */
 105 static translation_unit_t  *unit              = NULL;
 106 /** true if we are in an __extension__ context. */
 107 static bool                 in_gcc_extension  = false;
 108 static struct obstack       temp_obst;
 109 static entity_t            *anonymous_entity;
 110 static declaration_t      **incomplete_arrays;
 111 static elf_visibility_tag_t default_visibility = ELF_VISIBILITY_DEFAULT;
 112
 113
 114 #define PUSH_CURRENT_ENTITY(entity) \
 115         entity_t *const new_current_entity = (entity); \
 116         entity_t *const old_current_entity = current_entity; \
 117         ((void)(current_entity = new_current_entity))
 118 #define POP_CURRENT_ENTITY() (assert(current_entity == new_current_entity), (void)(current_entity = old_current_entity))
 119
 120 #define PUSH_PARENT(stmt) \
 121         statement_t *const new_parent = (stmt); \
 122         statement_t *const old_parent = current_parent; \
 123         ((void)(current_parent = new_parent))
 124 #define POP_PARENT() (assert(current_parent == new_parent), (void)(current_parent = old_parent))
 125
 126 #define PUSH_SCOPE(scope) \
 127         size_t   const top       = environment_top(); \
 128         scope_t *const new_scope = (scope); \
 129         scope_t *const old_scope = (new_scope ? scope_push(new_scope) : NULL)
 130 #define PUSH_SCOPE_STATEMENT(scope) PUSH_SCOPE(c_mode & (_C99 | _CXX) ? (scope) : NULL)
 131 #define POP_SCOPE() (new_scope ? assert(current_scope == new_scope), scope_pop(old_scope), environment_pop_to(top) : (void)0)
 132
 133 #define PUSH_EXTENSION() \
 134         (void)0; \
 135         bool const old_gcc_extension = in_gcc_extension; \
 136         while (accept(T___extension__)) { \
 137                 in_gcc_extension = true; \
 138         } \
 139         do {} while (0)
 140 #define POP_EXTENSION() \
 141         ((void)(in_gcc_extension = old_gcc_extension))
 142
 143 /** The token anchor set */
 144 static unsigned short token_anchor_set[T_LAST_TOKEN];
 145
 146 /** The current source position. */
 147 #define HERE (&token.base.source_position)
 148
 149 /** true if we are in GCC mode. */
 150 #define GNU_MODE ((c_mode & _GNUC) || in_gcc_extension)
 151
 152 static statement_t *parse_compound_statement(bool inside_expression_statement);
 153 static statement_t *parse_statement(void);
 154
 155 static expression_t *parse_subexpression(precedence_t);
 156 static expression_t *parse_expression(void);
 157 static type_t       *parse_typename(void);
 158 static void          parse_externals(void);
 159 static void          parse_external(void);
 160
 161 static void parse_compound_type_entries(compound_t *compound_declaration);
 162
 163 static void check_call_argument(type_t          *expected_type,
 164                                                                 call_argument_t *argument, unsigned pos);
 165
 166 typedef enum declarator_flags_t {
 167         DECL_FLAGS_NONE             = 0,
 168         DECL_MAY_BE_ABSTRACT        = 1U << 0,
 169         DECL_CREATE_COMPOUND_MEMBER = 1U << 1,
 170         DECL_IS_PARAMETER           = 1U << 2
 171 } declarator_flags_t;
 172
 173 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
 174                                   declarator_flags_t flags);
 175
 176 static void semantic_comparison(binary_expression_t *expression);
 177
 178 #define STORAGE_CLASSES       \
 179         STORAGE_CLASSES_NO_EXTERN \
 180         case T_extern:
 181
 182 #define STORAGE_CLASSES_NO_EXTERN \
 183         case T_typedef:         \
 184         case T_static:          \
 185         case T_auto:            \
 186         case T_register:        \
 187         case T__Thread_local:
 188
 189 #define TYPE_QUALIFIERS     \
 190         case T_const:           \
 191         case T_restrict:        \
 192         case T_volatile:        \
 193         case T_inline:          \
 194         case T__forceinline:    \
 195         case T___attribute__:
 196
 197 #define COMPLEX_SPECIFIERS  \
 198         case T__Complex:
 199 #define IMAGINARY_SPECIFIERS \
 200         case T__Imaginary:
 201
 202 #define TYPE_SPECIFIERS       \
 203         case T__Bool:             \
 204         case T___builtin_va_list: \
 205         case T___typeof__:        \
 206         case T__declspec:         \
 207         case T_bool:              \
 208         case T_char:              \
 209         case T_double:            \
 210         case T_enum:              \
 211         case T_float:             \
 212         case T_int:               \
 213         case T_long:              \
 214         case T_short:             \
 215         case T_signed:            \
 216         case T_struct:            \
 217         case T_union:             \
 218         case T_unsigned:          \
 219         case T_void:              \
 220         case T_wchar_t:           \
 221         case T__int8:             \
 222         case T__int16:            \
 223         case T__int32:            \
 224         case T__int64:            \
 225         case T__int128:           \
 226         COMPLEX_SPECIFIERS        \
 227         IMAGINARY_SPECIFIERS
 228
 229 #define DECLARATION_START   \
 230         STORAGE_CLASSES         \
 231         TYPE_QUALIFIERS         \
 232         TYPE_SPECIFIERS
 233
 234 #define DECLARATION_START_NO_EXTERN \
 235         STORAGE_CLASSES_NO_EXTERN       \
 236         TYPE_QUALIFIERS                 \
 237         TYPE_SPECIFIERS
 238
 239 #define EXPRESSION_START              \
 240         case '!':                         \
 241         case '&':                         \
 242         case '(':                         \
 243         case '*':                         \
 244         case '+':                         \
 245         case '-':                         \
 246         case '~':                         \
 247         case T_ANDAND:                    \
 248         case T_CHARACTER_CONSTANT:        \
 249         case T_NUMBER:                    \
 250         case T_MINUSMINUS:                \
 251         case T_PLUSPLUS:                  \
 252         case T_STRING_LITERAL:            \
 253         case T__Alignof:                  \
 254         case T___FUNCDNAME__:             \
 255         case T___FUNCSIG__:               \
 256         case T___PRETTY_FUNCTION__:       \
 257         case T___builtin_classify_type:   \
 258         case T___builtin_constant_p:      \
 259         case T___builtin_isgreater:       \
 260         case T___builtin_isgreaterequal:  \
 261         case T___builtin_isless:          \
 262         case T___builtin_islessequal:     \
 263         case T___builtin_islessgreater:   \
 264         case T___builtin_isunordered:     \
 265         case T___builtin_offsetof:        \
 266         case T___builtin_va_arg:          \
 267         case T___builtin_va_copy:         \
 268         case T___builtin_va_start:        \
 269         case T___func__:                  \
 270         case T___noop:                    \
 271         case T__assume:                   \
 272         case T_delete:                    \
 273         case T_false:                     \
 274         case T_sizeof:                    \
 275         case T_throw:                     \
 276         case T_true:
 277
 278 /**
 279  * Returns the size of a statement node.
 280  *
 281  * @param kind  the statement kind
 282  */
 283 static size_t get_statement_struct_size(statement_kind_t kind)
 284 {
 285         static const size_t sizes[] = {
 286                 [STATEMENT_ERROR]         = sizeof(statement_base_t),
 287                 [STATEMENT_EMPTY]         = sizeof(statement_base_t),
 288                 [STATEMENT_COMPOUND]      = sizeof(compound_statement_t),
 289                 [STATEMENT_RETURN]        = sizeof(return_statement_t),
 290                 [STATEMENT_DECLARATION]   = sizeof(declaration_statement_t),
 291                 [STATEMENT_IF]            = sizeof(if_statement_t),
 292                 [STATEMENT_SWITCH]        = sizeof(switch_statement_t),
 293                 [STATEMENT_EXPRESSION]    = sizeof(expression_statement_t),
 294                 [STATEMENT_CONTINUE]      = sizeof(statement_base_t),
 295                 [STATEMENT_BREAK]         = sizeof(statement_base_t),
 296                 [STATEMENT_COMPUTED_GOTO] = sizeof(computed_goto_statement_t),
 297                 [STATEMENT_GOTO]          = sizeof(goto_statement_t),
 298                 [STATEMENT_LABEL]         = sizeof(label_statement_t),
 299                 [STATEMENT_CASE_LABEL]    = sizeof(case_label_statement_t),
 300                 [STATEMENT_DO_WHILE]      = sizeof(do_while_statement_t),
 301                 [STATEMENT_FOR]           = sizeof(for_statement_t),
 302                 [STATEMENT_ASM]           = sizeof(asm_statement_t),
 303                 [STATEMENT_MS_TRY]        = sizeof(ms_try_statement_t),
 304                 [STATEMENT_LEAVE]         = sizeof(leave_statement_t)
 305         };
 306         assert((size_t)kind < lengthof(sizes));
 307         assert(sizes[kind] != 0);
 308         return sizes[kind];
 309 }
 310
 311 /**
 312  * Returns the size of an expression node.
 313  *
 314  * @param kind  the expression kind
 315  */
 316 static size_t get_expression_struct_size(expression_kind_t kind)
 317 {
 318         static const size_t sizes[] = {
 319                 [EXPR_ERROR]                      = sizeof(expression_base_t),
 320                 [EXPR_REFERENCE]                  = sizeof(reference_expression_t),
 321                 [EXPR_ENUM_CONSTANT]              = sizeof(reference_expression_t),
 322                 [EXPR_LITERAL_BOOLEAN]            = sizeof(literal_expression_t),
 323                 [EXPR_LITERAL_INTEGER]            = sizeof(literal_expression_t),
 324                 [EXPR_LITERAL_FLOATINGPOINT]      = sizeof(literal_expression_t),
 325                 [EXPR_LITERAL_CHARACTER]          = sizeof(string_literal_expression_t),
 326                 [EXPR_LITERAL_MS_NOOP]            = sizeof(literal_expression_t),
 327                 [EXPR_STRING_LITERAL]             = sizeof(string_literal_expression_t),
 328                 [EXPR_COMPOUND_LITERAL]           = sizeof(compound_literal_expression_t),
 329                 [EXPR_CALL]                       = sizeof(call_expression_t),
 330                 [EXPR_UNARY_FIRST]                = sizeof(unary_expression_t),
 331                 [EXPR_BINARY_FIRST]               = sizeof(binary_expression_t),
 332                 [EXPR_CONDITIONAL]                = sizeof(conditional_expression_t),
 333                 [EXPR_SELECT]                     = sizeof(select_expression_t),
 334                 [EXPR_ARRAY_ACCESS]               = sizeof(array_access_expression_t),
 335                 [EXPR_SIZEOF]                     = sizeof(typeprop_expression_t),
 336                 [EXPR_ALIGNOF]                    = sizeof(typeprop_expression_t),
 337                 [EXPR_CLASSIFY_TYPE]              = sizeof(classify_type_expression_t),
 338                 [EXPR_FUNCNAME]                   = sizeof(funcname_expression_t),
 339                 [EXPR_BUILTIN_CONSTANT_P]         = sizeof(builtin_constant_expression_t),
 340                 [EXPR_BUILTIN_TYPES_COMPATIBLE_P] = sizeof(builtin_types_compatible_expression_t),
 341                 [EXPR_OFFSETOF]                   = sizeof(offsetof_expression_t),
 342                 [EXPR_VA_START]                   = sizeof(va_start_expression_t),
 343                 [EXPR_VA_ARG]                     = sizeof(va_arg_expression_t),
 344                 [EXPR_VA_COPY]                    = sizeof(va_copy_expression_t),
 345                 [EXPR_STATEMENT]                  = sizeof(statement_expression_t),
 346                 [EXPR_LABEL_ADDRESS]              = sizeof(label_address_expression_t),
 347         };
 348         if (kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
 349                 return sizes[EXPR_UNARY_FIRST];
 350         }
 351         if (kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
 352                 return sizes[EXPR_BINARY_FIRST];
 353         }
 354         assert((size_t)kind < lengthof(sizes));
 355         assert(sizes[kind] != 0);
 356         return sizes[kind];
 357 }
 358
 359 /**
 360  * Allocate a statement node of given kind and initialize all
 361  * fields with zero. Sets its source position to the position
 362  * of the current token.
 363  */
 364 static statement_t *allocate_statement_zero(statement_kind_t kind)
 365 {
 366         size_t       size = get_statement_struct_size(kind);
 367         statement_t *res  = allocate_ast_zero(size);
 368
 369         res->base.kind            = kind;
 370         res->base.parent          = current_parent;
 371         res->base.source_position = *HERE;
 372         return res;
 373 }
 374
 375 /**
 376  * Allocate an expression node of given kind and initialize all
 377  * fields with zero.
 378  *
 379  * @param kind  the kind of the expression to allocate
 380  */
 381 static expression_t *allocate_expression_zero(expression_kind_t kind)
 382 {
 383         size_t        size = get_expression_struct_size(kind);
 384         expression_t *res  = allocate_ast_zero(size);
 385
 386         res->base.kind            = kind;
 387         res->base.type            = type_error_type;
 388         res->base.source_position = *HERE;
 389         return res;
 390 }
 391
 392 /**
 393  * Creates a new invalid expression at the source position
 394  * of the current token.
 395  */
 396 static expression_t *create_error_expression(void)
 397 {
 398         expression_t *expression = allocate_expression_zero(EXPR_ERROR);
 399         expression->base.type = type_error_type;
 400         return expression;
 401 }
 402
 403 /**
 404  * Creates a new invalid statement.
 405  */
 406 static statement_t *create_error_statement(void)
 407 {
 408         return allocate_statement_zero(STATEMENT_ERROR);
 409 }
 410
 411 /**
 412  * Allocate a new empty statement.
 413  */
 414 static statement_t *create_empty_statement(void)
 415 {
 416         return allocate_statement_zero(STATEMENT_EMPTY);
 417 }
 418
 419 /**
 420  * Returns the size of an initializer node.
 421  *
 422  * @param kind  the initializer kind
 423  */
 424 static size_t get_initializer_size(initializer_kind_t kind)
 425 {
 426         static const size_t sizes[] = {
 427                 [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
 428                 [INITIALIZER_STRING]      = sizeof(initializer_value_t),
 429                 [INITIALIZER_LIST]        = sizeof(initializer_list_t),
 430                 [INITIALIZER_DESIGNATOR]  = sizeof(initializer_designator_t)
 431         };
 432         assert((size_t)kind < lengthof(sizes));
 433         assert(sizes[kind] != 0);
 434         return sizes[kind];
 435 }
 436
 437 /**
 438  * Allocate an initializer node of given kind and initialize all
 439  * fields with zero.
 440  */
 441 static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 442 {
 443         initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
 444         result->kind          = kind;
 445
 446         return result;
 447 }
 448
 449 /**
 450  * Returns the index of the top element of the environment stack.
 451  */
 452 static size_t environment_top(void)
 453 {
 454         return ARR_LEN(environment_stack);
 455 }
 456
 457 /**
 458  * Returns the index of the top element of the global label stack.
 459  */
 460 static size_t label_top(void)
 461 {
 462         return ARR_LEN(label_stack);
 463 }
 464
 465 /**
 466  * Return the next token.
 467  */
 468 static inline void next_token(void)
 469 {
 470         token                              = lookahead_buffer[lookahead_bufpos];
 471         lookahead_buffer[lookahead_bufpos] = pp_token;
 472         next_preprocessing_token();
 473
 474         lookahead_bufpos = (lookahead_bufpos + 1) % MAX_LOOKAHEAD;
 475
 476 #ifdef PRINT_TOKENS
 477         print_token(stderr, &token);
 478         fprintf(stderr, "\n");
 479 #endif
 480 }
 481
 482 static inline void eat(token_kind_t const kind)
 483 {
 484         assert(token.kind == kind);
 485         (void)kind;
 486         next_token();
 487 }
 488
 489 /**
 490  * Consume the current token, if it is of the expected kind.
 491  *
 492  * @param  kind  The kind of token to consume.
 493  * @return Whether the token was consumed.
 494  */
 495 static inline bool accept(token_kind_t const kind)
 496 {
 497         if (token.kind == kind) {
 498                 eat(kind);
 499                 return true;
 500         } else {
 501                 return false;
 502         }
 503 }
 504
 505 /**
 506  * Return the next token with a given lookahead.
 507  */
 508 static inline const token_t *look_ahead(size_t num)
 509 {
 510         assert(0 < num && num <= MAX_LOOKAHEAD);
 511         size_t pos = (lookahead_bufpos + num - 1) % MAX_LOOKAHEAD;
 512         return &lookahead_buffer[pos];
 513 }
 514
 515 /**
 516  * Adds a token type to the token type anchor set (a multi-set).
 517  */
 518 static void add_anchor_token(token_kind_t const token_kind)
 519 {
 520         assert(token_kind < T_LAST_TOKEN);
 521         ++token_anchor_set[token_kind];
 522 }
 523
 524 /**
 525  * Remove a token type from the token type anchor set (a multi-set).
 526  */
 527 static void rem_anchor_token(token_kind_t const token_kind)
 528 {
 529         assert(token_kind < T_LAST_TOKEN);
 530         assert(token_anchor_set[token_kind] != 0);
 531         --token_anchor_set[token_kind];
 532 }
 533
 534 /**
 535  * Eat tokens until a matching token type is found.
 536  */
 537 static void eat_until_matching_token(token_kind_t const type)
 538 {
 539         token_kind_t end_token;
 540         switch (type) {
 541                 case '(': end_token = ')';  break;
 542                 case '{': end_token = '}';  break;
 543                 case '[': end_token = ']';  break;
 544                 default:  end_token = type; break;
 545         }
 546
 547         unsigned parenthesis_count = 0;
 548         unsigned brace_count       = 0;
 549         unsigned bracket_count     = 0;
 550         while (token.kind        != end_token ||
 551                parenthesis_count != 0         ||
 552                brace_count       != 0         ||
 553                bracket_count     != 0) {
 554                 switch (token.kind) {
 555                 case T_EOF: return;
 556                 case '(': ++parenthesis_count; break;
 557                 case '{': ++brace_count;       break;
 558                 case '[': ++bracket_count;     break;
 559
 560                 case ')':
 561                         if (parenthesis_count > 0)
 562                                 --parenthesis_count;
 563                         goto check_stop;
 564
 565                 case '}':
 566                         if (brace_count > 0)
 567                                 --brace_count;
 568                         goto check_stop;
 569
 570                 case ']':
 571                         if (bracket_count > 0)
 572                                 --bracket_count;
 573 check_stop:
 574                         if (token.kind        == end_token &&
 575                             parenthesis_count == 0         &&
 576                             brace_count       == 0         &&
 577                             bracket_count     == 0)
 578                                 return;
 579                         break;
 580
 581                 default:
 582                         break;
 583                 }
 584                 next_token();
 585         }
 586 }
 587
 588 /**
 589  * Eat input tokens until an anchor is found.
 590  */
 591 static void eat_until_anchor(void)
 592 {
 593         while (token_anchor_set[token.kind] == 0) {
 594                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
 595                         eat_until_matching_token(token.kind);
 596                 next_token();
 597         }
 598 }
 599
 600 /**
 601  * Eat a whole block from input tokens.
 602  */
 603 static void eat_block(void)
 604 {
 605         eat_until_matching_token('{');
 606         accept('}');
 607 }
 608
 609 /**
 610  * Report a parse error because an expected token was not found.
 611  */
 612 static
 613 #if defined __GNUC__ && __GNUC__ >= 4
 614 __attribute__((sentinel))
 615 #endif
 616 void parse_error_expected(const char *message, ...)
 617 {
 618         if (message != NULL) {
 619                 errorf(HERE, "%s", message);
 620         }
 621         va_list ap;
 622         va_start(ap, message);
 623         errorf(HERE, "got %K, expected %#k", &token, &ap, ", ");
 624         va_end(ap);
 625 }
 626
 627 /**
 628  * Report an incompatible type.
 629  */
 630 static void type_error_incompatible(const char *msg,
 631                 const source_position_t *source_position, type_t *type1, type_t *type2)
 632 {
 633         errorf(source_position, "%s, incompatible types: '%T' - '%T'",
 634                msg, type1, type2);
 635 }
 636
 637 static bool skip_till(token_kind_t const expected, char const *const context)
 638 {
 639         if (UNLIKELY(token.kind != expected)) {
 640                 parse_error_expected(context, expected, NULL);
 641                 add_anchor_token(expected);
 642                 eat_until_anchor();
 643                 rem_anchor_token(expected);
 644                 if (token.kind != expected)
 645                         return false;
 646         }
 647         return true;
 648 }
 649
 650 /**
 651  * Expect the current token is the expected token.
 652  * If not, generate an error and skip until the next anchor.
 653  */
 654 static void expect(token_kind_t const expected)
 655 {
 656         if (skip_till(expected, NULL))
 657                 eat(expected);
 658 }
 659
 660 static symbol_t *expect_identifier(char const *const context, source_position_t *const pos)
 661 {
 662         if (!skip_till(T_IDENTIFIER, context))
 663                 return NULL;
 664         symbol_t *const sym = token.base.symbol;
 665         if (pos)
 666                 *pos = *HERE;
 667         eat(T_IDENTIFIER);
 668         return sym;
 669 }
 670
 671 /**
 672  * Push a given scope on the scope stack and make it the
 673  * current scope
 674  */
 675 static scope_t *scope_push(scope_t *new_scope)
 676 {
 677         if (current_scope != NULL) {
 678                 new_scope->depth = current_scope->depth + 1;
 679         }
 680
 681         scope_t *old_scope = current_scope;
 682         current_scope      = new_scope;
 683         return old_scope;
 684 }
 685
 686 /**
 687  * Pop the current scope from the scope stack.
 688  */
 689 static void scope_pop(scope_t *old_scope)
 690 {
 691         current_scope = old_scope;
 692 }
 693
 694 /**
 695  * Search an entity by its symbol in a given namespace.
 696  */
 697 static entity_t *get_entity(const symbol_t *const symbol,
 698                             namespace_tag_t namespc)
 699 {
 700         entity_t *entity = symbol->entity;
 701         for (; entity != NULL; entity = entity->base.symbol_next) {
 702                 if ((namespace_tag_t)entity->base.namespc == namespc)
 703                         return entity;
 704         }
 705
 706         return NULL;
 707 }
 708
 709 /* §6.2.3:1 24)  There is only one name space for tags even though three are
 710  * possible. */
 711 static entity_t *get_tag(symbol_t const *const symbol,
 712                          entity_kind_tag_t const kind)
 713 {
 714         entity_t *entity = get_entity(symbol, NAMESPACE_TAG);
 715         if (entity != NULL && (entity_kind_tag_t)entity->kind != kind) {
 716                 errorf(HERE,
 717                                 "'%Y' defined as wrong kind of tag (previous definition %P)",
 718                                 symbol, &entity->base.source_position);
 719                 entity = NULL;
 720         }
 721         return entity;
 722 }
 723
 724 /**
 725  * pushs an entity on the environment stack and links the corresponding symbol
 726  * it.
 727  */
 728 static void stack_push(stack_entry_t **stack_ptr, entity_t *entity)
 729 {
 730         symbol_t           *symbol  = entity->base.symbol;
 731         entity_namespace_t  namespc = entity->base.namespc;
 732         assert(namespc != 0);
 733
 734         /* replace/add entity into entity list of the symbol */
 735         entity_t **anchor;
 736         entity_t  *iter;
 737         for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 738                 iter = *anchor;
 739                 if (iter == NULL)
 740                         break;
 741
 742                 /* replace an entry? */
 743                 if (iter->base.namespc == namespc) {
 744                         entity->base.symbol_next = iter->base.symbol_next;
 745                         break;
 746                 }
 747         }
 748         *anchor = entity;
 749
 750         /* remember old declaration */
 751         stack_entry_t entry;
 752         entry.symbol     = symbol;
 753         entry.old_entity = iter;
 754         entry.namespc    = namespc;
 755         ARR_APP1(stack_entry_t, *stack_ptr, entry);
 756 }
 757
 758 /**
 759  * Push an entity on the environment stack.
 760  */
 761 static void environment_push(entity_t *entity)
 762 {
 763         assert(entity->base.source_position.input_name != NULL);
 764         assert(entity->base.parent_scope != NULL);
 765         stack_push(&environment_stack, entity);
 766 }
 767
 768 /**
 769  * Push a declaration on the global label stack.
 770  *
 771  * @param declaration  the declaration
 772  */
 773 static void label_push(entity_t *label)
 774 {
 775         /* we abuse the parameters scope as parent for the labels */
 776         label->base.parent_scope = &current_function->parameters;
 777         stack_push(&label_stack, label);
 778 }
 779
 780 /**
 781  * pops symbols from the environment stack until @p new_top is the top element
 782  */
 783 static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 784 {
 785         stack_entry_t *stack = *stack_ptr;
 786         size_t         top   = ARR_LEN(stack);
 787         size_t         i;
 788
 789         assert(new_top <= top);
 790         if (new_top == top)
 791                 return;
 792
 793         for (i = top; i > new_top; --i) {
 794                 stack_entry_t *entry = &stack[i - 1];
 795
 796                 entity_t           *old_entity = entry->old_entity;
 797                 symbol_t           *symbol     = entry->symbol;
 798                 entity_namespace_t  namespc    = entry->namespc;
 799
 800                 /* replace with old_entity/remove */
 801                 entity_t **anchor;
 802                 entity_t  *iter;
 803                 for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 804                         iter = *anchor;
 805                         assert(iter != NULL);
 806                         /* replace an entry? */
 807                         if (iter->base.namespc == namespc)
 808                                 break;
 809                 }
 810
 811                 /* restore definition from outer scopes (if there was one) */
 812                 if (old_entity != NULL) {
 813                         old_entity->base.symbol_next = iter->base.symbol_next;
 814                         *anchor                      = old_entity;
 815                 } else {
 816                         /* remove entry from list */
 817                         *anchor = iter->base.symbol_next;
 818                 }
 819         }
 820
 821         ARR_SHRINKLEN(*stack_ptr, new_top);
 822 }
 823
 824 /**
 825  * Pop all entries from the environment stack until the new_top
 826  * is reached.
 827  *
 828  * @param new_top  the new stack top
 829  */
 830 static void environment_pop_to(size_t new_top)
 831 {
 832         stack_pop_to(&environment_stack, new_top);
 833 }
 834
 835 /**
 836  * Pop all entries from the global label stack until the new_top
 837  * is reached.
 838  *
 839  * @param new_top  the new stack top
 840  */
 841 static void label_pop_to(size_t new_top)
 842 {
 843         stack_pop_to(&label_stack, new_top);
 844 }
 845
 846 static atomic_type_kind_t get_akind(const type_t *type)
 847 {
 848         assert(type->kind == TYPE_ATOMIC || type->kind == TYPE_COMPLEX
 849                || type->kind == TYPE_IMAGINARY || type->kind == TYPE_ENUM);
 850         return type->atomic.akind;
 851 }
 852
 853 /**
 854  * §6.3.1.1:2  Do integer promotion for a given type.
 855  *
 856  * @param type  the type to promote
 857  * @return the promoted type
 858  */
 859 static type_t *promote_integer(type_t *type)
 860 {
 861         if (get_akind_rank(get_akind(type)) < get_akind_rank(ATOMIC_TYPE_INT))
 862                 type = type_int;
 863
 864         return type;
 865 }
 866
 867 /**
 868  * Check if a given expression represents a null pointer constant.
 869  *
 870  * @param expression  the expression to check
 871  */
 872 static bool is_null_pointer_constant(const expression_t *expression)
 873 {
 874         /* skip void* cast */
 875         if (expression->kind == EXPR_UNARY_CAST) {
 876                 type_t *const type = skip_typeref(expression->base.type);
 877                 if (types_compatible(type, type_void_ptr))
 878                         expression = expression->unary.value;
 879         }
 880
 881         type_t *const type = skip_typeref(expression->base.type);
 882         if (!is_type_integer(type))
 883                 return false;
 884         switch (is_constant_expression(expression)) {
 885                 case EXPR_CLASS_ERROR:    return true;
 886                 case EXPR_CLASS_CONSTANT: return !fold_constant_to_bool(expression);
 887                 default:                  return false;
 888         }
 889 }
 890
 891 /**
 892  * Create an implicit cast expression.
 893  *
 894  * @param expression  the expression to cast
 895  * @param dest_type   the destination type
 896  */
 897 static expression_t *create_implicit_cast(expression_t *expression,
 898                                           type_t *dest_type)
 899 {
 900         type_t *const source_type = expression->base.type;
 901
 902         if (source_type == dest_type)
 903                 return expression;
 904
 905         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
 906         cast->unary.value   = expression;
 907         cast->base.type     = dest_type;
 908         cast->base.implicit = true;
 909
 910         return cast;
 911 }
 912
 913 typedef enum assign_error_t {
 914         ASSIGN_SUCCESS,
 915         ASSIGN_ERROR_INCOMPATIBLE,
 916         ASSIGN_ERROR_POINTER_QUALIFIER_MISSING,
 917         ASSIGN_WARNING_POINTER_INCOMPATIBLE,
 918         ASSIGN_WARNING_POINTER_FROM_INT,
 919         ASSIGN_WARNING_INT_FROM_POINTER
 920 } assign_error_t;
 921
 922 static void report_assign_error(assign_error_t error, type_t *orig_type_left, expression_t const *const right, char const *const context, source_position_t const *const pos)
 923 {
 924         type_t *const orig_type_right = right->base.type;
 925         type_t *const type_left       = skip_typeref(orig_type_left);
 926         type_t *const type_right      = skip_typeref(orig_type_right);
 927
 928         switch (error) {
 929         case ASSIGN_SUCCESS:
 930                 return;
 931         case ASSIGN_ERROR_INCOMPATIBLE:
 932                 errorf(pos, "destination type '%T' in %s is incompatible with type '%T'", orig_type_left, context, orig_type_right);
 933                 return;
 934
 935         case ASSIGN_ERROR_POINTER_QUALIFIER_MISSING: {
 936                 type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
 937                 type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 938
 939                 /* the left type has all qualifiers from the right type */
 940                 unsigned missing_qualifiers = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 941                 warningf(WARN_OTHER, pos, "destination type '%T' in %s from type '%T' lacks qualifiers '%Q' in pointer target type", orig_type_left, context, orig_type_right, missing_qualifiers);
 942                 return;
 943         }
 944
 945         case ASSIGN_WARNING_POINTER_INCOMPATIBLE:
 946                 warningf(WARN_OTHER, pos, "destination type '%T' in %s is incompatible with '%E' of type '%T'", orig_type_left, context, right, orig_type_right);
 947                 return;
 948
 949         case ASSIGN_WARNING_POINTER_FROM_INT:
 950                 warningf(WARN_OTHER, pos, "%s makes pointer '%T' from integer '%T' without a cast", context, orig_type_left, orig_type_right);
 951                 return;
 952
 953         case ASSIGN_WARNING_INT_FROM_POINTER:
 954                 warningf(WARN_OTHER, pos, "%s makes integer '%T' from pointer '%T' without a cast", context, orig_type_left, orig_type_right);
 955                 return;
 956
 957         default:
 958                 panic("invalid error value");
 959         }
 960 }
 961
 962 /** Implements the rules from §6.5.16.1 */
 963 static assign_error_t semantic_assign(type_t *orig_type_left,
 964                                       const expression_t *const right)
 965 {
 966         type_t *const orig_type_right = right->base.type;
 967         type_t *const type_left       = skip_typeref(orig_type_left);
 968         type_t *const type_right      = skip_typeref(orig_type_right);
 969
 970         if (is_type_pointer(type_left)) {
 971                 if (is_null_pointer_constant(right)) {
 972                         return ASSIGN_SUCCESS;
 973                 } else if (is_type_pointer(type_right)) {
 974                         type_t *points_to_left
 975                                 = skip_typeref(type_left->pointer.points_to);
 976                         type_t *points_to_right
 977                                 = skip_typeref(type_right->pointer.points_to);
 978                         assign_error_t res = ASSIGN_SUCCESS;
 979
 980                         /* the left type has all qualifiers from the right type */
 981                         unsigned missing_qualifiers
 982                                 = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 983                         if (missing_qualifiers != 0) {
 984                                 res = ASSIGN_ERROR_POINTER_QUALIFIER_MISSING;
 985                         }
 986
 987                         points_to_left  = get_unqualified_type(points_to_left);
 988                         points_to_right = get_unqualified_type(points_to_right);
 989
 990                         if (is_type_void(points_to_left))
 991                                 return res;
 992
 993                         if (is_type_void(points_to_right)) {
 994                                 /* ISO/IEC 14882:1998(E) §C.1.2:6 */
 995                                 return c_mode & _CXX ? ASSIGN_ERROR_INCOMPATIBLE : res;
 996                         }
 997
 998                         if (!types_compatible(points_to_left, points_to_right)) {
 999                                 return ASSIGN_WARNING_POINTER_INCOMPATIBLE;
1000                         }
1001
1002                         return res;
1003                 } else if (is_type_integer(type_right)) {
1004                         return ASSIGN_WARNING_POINTER_FROM_INT;
1005                 }
1006         } else if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
1007                         (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
1008                                 && is_type_pointer(type_right))) {
1009                 return ASSIGN_SUCCESS;
1010         } else if (is_type_compound(type_left) && is_type_compound(type_right)) {
1011                 type_t *const unqual_type_left  = get_unqualified_type(type_left);
1012                 type_t *const unqual_type_right = get_unqualified_type(type_right);
1013                 if (types_compatible(unqual_type_left, unqual_type_right)) {
1014                         return ASSIGN_SUCCESS;
1015                 }
1016         } else if (is_type_integer(type_left) && is_type_pointer(type_right)) {
1017                 return ASSIGN_WARNING_INT_FROM_POINTER;
1018         }
1019
1020         if (!is_type_valid(type_left) || !is_type_valid(type_right))
1021                 return ASSIGN_SUCCESS;
1022
1023         return ASSIGN_ERROR_INCOMPATIBLE;
1024 }
1025
1026 static expression_t *parse_constant_expression(void)
1027 {
1028         expression_t *result = parse_subexpression(PREC_CONDITIONAL);
1029
1030         if (is_constant_expression(result) == EXPR_CLASS_VARIABLE) {
1031                 errorf(&result->base.source_position,
1032                        "expression '%E' is not constant", result);
1033         }
1034
1035         return result;
1036 }
1037
1038 static expression_t *parse_assignment_expression(void)
1039 {
1040         return parse_subexpression(PREC_ASSIGNMENT);
1041 }
1042
1043 static void append_string(string_t const *const s)
1044 {
1045         /* FIXME Using the ast_obstack is a hack.  Using the symbol_obstack is not
1046          * possible, because other tokens are grown there alongside. */
1047         obstack_grow(&ast_obstack, s->begin, s->size);
1048 }
1049
1050 static string_t finish_string(string_encoding_t const enc)
1051 {
1052         obstack_1grow(&ast_obstack, '\0');
1053         size_t      const size   = obstack_object_size(&ast_obstack) - 1;
1054         char const *const string = obstack_finish(&ast_obstack);
1055         return (string_t){ string, size, enc };
1056 }
1057
1058 static string_t concat_string_literals(void)
1059 {
1060         assert(token.kind == T_STRING_LITERAL);
1061
1062         string_t result;
1063         if (look_ahead(1)->kind == T_STRING_LITERAL) {
1064                 append_string(&token.literal.string);
1065                 eat(T_STRING_LITERAL);
1066                 warningf(WARN_TRADITIONAL, HERE, "traditional C rejects string constant concatenation");
1067                 string_encoding_t enc = token.literal.string.encoding;
1068                 do {
1069                         string_encoding_t const new_enc = token.literal.string.encoding;
1070                         if (new_enc != enc && new_enc != STRING_ENCODING_CHAR) {
1071                                 if (enc == STRING_ENCODING_CHAR) {
1072                                         enc = new_enc;
1073                                 } else {
1074                                         errorf(HERE, "concatenating string literals with encodings %s and %s", get_string_encoding_prefix(enc), get_string_encoding_prefix(new_enc));
1075                                 }
1076                         }
1077                         append_string(&token.literal.string);
1078                         eat(T_STRING_LITERAL);
1079                 } while (token.kind == T_STRING_LITERAL);
1080                 result = finish_string(enc);
1081         } else {
1082                 result = token.literal.string;
1083                 eat(T_STRING_LITERAL);
1084         }
1085
1086         return result;
1087 }
1088
1089 static string_t parse_string_literals(char const *const context)
1090 {
1091         if (!skip_till(T_STRING_LITERAL, context))
1092                 return (string_t){ "", 0, STRING_ENCODING_CHAR };
1093
1094         source_position_t const pos = *HERE;
1095         string_t          const res = concat_string_literals();
1096
1097         if (res.encoding != STRING_ENCODING_CHAR) {
1098                 errorf(&pos, "expected plain string literal, got %s string literal", get_string_encoding_prefix(res.encoding));
1099         }
1100
1101         return res;
1102 }
1103
1104 static attribute_t *allocate_attribute_zero(attribute_kind_t kind)
1105 {
1106         attribute_t *attribute = allocate_ast_zero(sizeof(*attribute));
1107         attribute->kind            = kind;
1108         attribute->source_position = *HERE;
1109         return attribute;
1110 }
1111
1112 /**
1113  * Parse (gcc) attribute argument. From gcc comments in gcc source:
1114  *
1115  *  attribute:
1116  *    __attribute__ ( ( attribute-list ) )
1117  *
1118  *  attribute-list:
1119  *    attrib
1120  *    attribute_list , attrib
1121  *
1122  *  attrib:
1123  *    empty
1124  *    any-word
1125  *    any-word ( identifier )
1126  *    any-word ( identifier , nonempty-expr-list )
1127  *    any-word ( expr-list )
1128  *
1129  *  where the "identifier" must not be declared as a type, and
1130  *  "any-word" may be any identifier (including one declared as a
1131  *  type), a reserved word storage class specifier, type specifier or
1132  *  type qualifier.  ??? This still leaves out most reserved keywords
1133  *  (following the old parser), shouldn't we include them, and why not
1134  *  allow identifiers declared as types to start the arguments?
1135  *
1136  *  Matze: this all looks confusing and little systematic, so we're even less
1137  *  strict and parse any list of things which are identifiers or
1138  *  (assignment-)expressions.
1139  */
1140 static attribute_argument_t *parse_attribute_arguments(void)
1141 {
1142         attribute_argument_t  *first  = NULL;
1143         attribute_argument_t **anchor = &first;
1144         if (token.kind != ')') do {
1145                 attribute_argument_t *argument = allocate_ast_zero(sizeof(*argument));
1146
1147                 /* is it an identifier */
1148                 if (token.kind == T_IDENTIFIER
1149                                 && (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
1150                         argument->kind     = ATTRIBUTE_ARGUMENT_SYMBOL;
1151                         argument->v.symbol = token.base.symbol;
1152                         eat(T_IDENTIFIER);
1153                 } else {
1154                         /* must be an expression */
1155                         expression_t *expression = parse_assignment_expression();
1156
1157                         argument->kind         = ATTRIBUTE_ARGUMENT_EXPRESSION;
1158                         argument->v.expression = expression;
1159                 }
1160
1161                 /* append argument */
1162                 *anchor = argument;
1163                 anchor  = &argument->next;
1164         } while (accept(','));
1165         expect(')');
1166         return first;
1167 }
1168
1169 static attribute_t *parse_attribute_asm(void)
1170 {
1171         attribute_t *attribute = allocate_attribute_zero(ATTRIBUTE_GNU_ASM);
1172         eat(T_asm);
1173         expect('(');
1174         attribute->a.arguments = parse_attribute_arguments();
1175         return attribute;
1176 }
1177
1178 static attribute_t *parse_attribute_gnu_single(void)
1179 {
1180         /* parse "any-word" */
1181         symbol_t *const symbol = token.base.symbol;
1182         if (symbol == NULL) {
1183                 parse_error_expected("while parsing attribute((", T_IDENTIFIER, NULL);
1184                 return NULL;
1185         }
1186
1187         attribute_kind_t  kind;
1188         char const *const name = symbol->string;
1189         for (kind = ATTRIBUTE_GNU_FIRST;; ++kind) {
1190                 if (kind > ATTRIBUTE_GNU_LAST) {
1191                         /* special case for "__const" */
1192                         if (token.kind == T_const) {
1193                                 kind = ATTRIBUTE_GNU_CONST;
1194                                 break;
1195                         }
1196
1197                         warningf(WARN_ATTRIBUTE, HERE, "unknown attribute '%s' ignored", name);
1198                         /* TODO: we should still save the attribute in the list... */
1199                         kind = ATTRIBUTE_UNKNOWN;
1200                         break;
1201                 }
1202
1203                 const char *attribute_name = get_attribute_name(kind);
1204                 if (attribute_name != NULL && streq_underscore(attribute_name, name))
1205                         break;
1206         }
1207
1208         attribute_t *attribute = allocate_attribute_zero(kind);
1209         next_token();
1210
1211         /* parse arguments */
1212         if (accept('('))
1213                 attribute->a.arguments = parse_attribute_arguments();
1214
1215         return attribute;
1216 }
1217
1218 static attribute_t *parse_attribute_gnu(void)
1219 {
1220         attribute_t  *first  = NULL;
1221         attribute_t **anchor = &first;
1222
1223         eat(T___attribute__);
1224         add_anchor_token(')');
1225         add_anchor_token(',');
1226         expect('(');
1227         expect('(');
1228
1229         if (token.kind != ')') do {
1230                 attribute_t *attribute = parse_attribute_gnu_single();
1231                 if (attribute) {
1232                         *anchor = attribute;
1233                         anchor  = &attribute->next;
1234                 }
1235         } while (accept(','));
1236         rem_anchor_token(',');
1237         rem_anchor_token(')');
1238
1239         expect(')');
1240         expect(')');
1241         return first;
1242 }
1243
1244 /** Parse attributes. */
1245 static attribute_t *parse_attributes(attribute_t *first)
1246 {
1247         attribute_t **anchor = &first;
1248         for (;;) {
1249                 while (*anchor != NULL)
1250                         anchor = &(*anchor)->next;
1251
1252                 attribute_t *attribute;
1253                 switch (token.kind) {
1254                 case T___attribute__:
1255                         attribute = parse_attribute_gnu();
1256                         if (attribute == NULL)
1257                                 continue;
1258                         break;
1259
1260                 case T_asm:
1261                         attribute = parse_attribute_asm();
1262                         break;
1263
1264                 case T_cdecl:
1265                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_CDECL);
1266                         eat(T_cdecl);
1267                         break;
1268
1269                 case T__fastcall:
1270                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FASTCALL);
1271                         eat(T__fastcall);
1272                         break;
1273
1274                 case T__forceinline:
1275                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FORCEINLINE);
1276                         eat(T__forceinline);
1277                         break;
1278
1279                 case T__stdcall:
1280                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_STDCALL);
1281                         eat(T__stdcall);
1282                         break;
1283
1284                 case T___thiscall:
1285                         /* TODO record modifier */
1286                         warningf(WARN_OTHER, HERE, "Ignoring declaration modifier %K", &token);
1287                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_THISCALL);
1288                         eat(T___thiscall);
1289                         break;
1290
1291                 default:
1292                         return first;
1293                 }
1294
1295                 *anchor = attribute;
1296                 anchor  = &attribute->next;
1297         }
1298 }
1299
1300 static void mark_vars_read(expression_t *expr, entity_t *lhs_ent);
1301
1302 static entity_t *determine_lhs_ent(expression_t *const expr,
1303                                    entity_t *lhs_ent)
1304 {
1305         switch (expr->kind) {
1306                 case EXPR_REFERENCE: {
1307                         entity_t *const entity = expr->reference.entity;
1308                         /* we should only find variables as lvalues... */
1309                         if (entity->base.kind != ENTITY_VARIABLE
1310                                         && entity->base.kind != ENTITY_PARAMETER)
1311                                 return NULL;
1312
1313                         return entity;
1314                 }
1315
1316                 case EXPR_ARRAY_ACCESS: {
1317                         expression_t *const ref = expr->array_access.array_ref;
1318                         entity_t     *      ent = NULL;
1319                         if (is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1320                                 ent     = determine_lhs_ent(ref, lhs_ent);
1321                                 lhs_ent = ent;
1322                         } else {
1323                                 mark_vars_read(ref, lhs_ent);
1324                         }
1325                         mark_vars_read(expr->array_access.index, lhs_ent);
1326                         return ent;
1327                 }
1328
1329                 case EXPR_SELECT: {
1330                         mark_vars_read(expr->select.compound, lhs_ent);
1331                         if (is_type_compound(skip_typeref(expr->base.type)))
1332                                 return determine_lhs_ent(expr->select.compound, lhs_ent);
1333                         return NULL;
1334                 }
1335
1336                 case EXPR_UNARY_DEREFERENCE: {
1337                         expression_t *const val = expr->unary.value;
1338                         if (val->kind == EXPR_UNARY_TAKE_ADDRESS) {
1339                                 /* *&x is a NOP */
1340                                 return determine_lhs_ent(val->unary.value, lhs_ent);
1341                         } else {
1342                                 mark_vars_read(val, NULL);
1343                                 return NULL;
1344                         }
1345                 }
1346
1347                 default:
1348                         mark_vars_read(expr, NULL);
1349                         return NULL;
1350         }
1351 }
1352
1353 #define ENT_ANY ((entity_t*)-1)
1354
1355 /**
1356  * Mark declarations, which are read.  This is used to detect variables, which
1357  * are never read.
1358  * Example:
1359  * x = x + 1;
1360  *   x is not marked as "read", because it is only read to calculate its own new
1361  *   value.
1362  *
1363  * x += y; y += x;
1364  *   x and y are not detected as "not read", because multiple variables are
1365  *   involved.
1366  */
1367 static void mark_vars_read(expression_t *const expr, entity_t *lhs_ent)
1368 {
1369         switch (expr->kind) {
1370                 case EXPR_REFERENCE: {
1371                         entity_t *const entity = expr->reference.entity;
1372                         if (entity->kind != ENTITY_VARIABLE
1373                                         && entity->kind != ENTITY_PARAMETER)
1374                                 return;
1375
1376                         if (lhs_ent != entity && lhs_ent != ENT_ANY) {
1377                                 entity->variable.read = true;
1378                         }
1379                         return;
1380                 }
1381
1382                 case EXPR_CALL:
1383                         // TODO respect pure/const
1384                         mark_vars_read(expr->call.function, NULL);
1385                         for (call_argument_t *arg = expr->call.arguments; arg != NULL; arg = arg->next) {
1386                                 mark_vars_read(arg->expression, NULL);
1387                         }
1388                         return;
1389
1390                 case EXPR_CONDITIONAL:
1391                         // TODO lhs_decl should depend on whether true/false have an effect
1392                         mark_vars_read(expr->conditional.condition, NULL);
1393                         if (expr->conditional.true_expression != NULL)
1394                                 mark_vars_read(expr->conditional.true_expression, lhs_ent);
1395                         mark_vars_read(expr->conditional.false_expression, lhs_ent);
1396                         return;
1397
1398                 case EXPR_SELECT:
1399                         if (lhs_ent == ENT_ANY
1400                                         && !is_type_compound(skip_typeref(expr->base.type)))
1401                                 lhs_ent = NULL;
1402                         mark_vars_read(expr->select.compound, lhs_ent);
1403                         return;
1404
1405                 case EXPR_ARRAY_ACCESS: {
1406                         mark_vars_read(expr->array_access.index, lhs_ent);
1407                         expression_t *const ref = expr->array_access.array_ref;
1408                         if (!is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1409                                 if (lhs_ent == ENT_ANY)
1410                                         lhs_ent = NULL;
1411                         }
1412                         mark_vars_read(ref, lhs_ent);
1413                         return;
1414                 }
1415
1416                 case EXPR_VA_ARG:
1417                         mark_vars_read(expr->va_arge.ap, lhs_ent);
1418                         return;
1419
1420                 case EXPR_VA_COPY:
1421                         mark_vars_read(expr->va_copye.src, lhs_ent);
1422                         return;
1423
1424                 case EXPR_UNARY_CAST:
1425                         /* Special case: Use void cast to mark a variable as "read" */
1426                         if (is_type_void(skip_typeref(expr->base.type)))
1427                                 lhs_ent = NULL;
1428                         goto unary;
1429
1430
1431                 case EXPR_UNARY_THROW:
1432                         if (expr->unary.value == NULL)
1433                                 return;
1434                         /* FALLTHROUGH */
1435                 case EXPR_UNARY_DEREFERENCE:
1436                 case EXPR_UNARY_DELETE:
1437                 case EXPR_UNARY_DELETE_ARRAY:
1438                         if (lhs_ent == ENT_ANY)
1439                                 lhs_ent = NULL;
1440                         goto unary;
1441
1442                 case EXPR_UNARY_NEGATE:
1443                 case EXPR_UNARY_PLUS:
1444                 case EXPR_UNARY_BITWISE_NEGATE:
1445                 case EXPR_UNARY_NOT:
1446                 case EXPR_UNARY_TAKE_ADDRESS:
1447                 case EXPR_UNARY_POSTFIX_INCREMENT:
1448                 case EXPR_UNARY_POSTFIX_DECREMENT:
1449                 case EXPR_UNARY_PREFIX_INCREMENT:
1450                 case EXPR_UNARY_PREFIX_DECREMENT:
1451                 case EXPR_UNARY_ASSUME:
1452 unary:
1453                         mark_vars_read(expr->unary.value, lhs_ent);
1454                         return;
1455
1456                 case EXPR_BINARY_ADD:
1457                 case EXPR_BINARY_SUB:
1458                 case EXPR_BINARY_MUL:
1459                 case EXPR_BINARY_DIV:
1460                 case EXPR_BINARY_MOD:
1461                 case EXPR_BINARY_EQUAL:
1462                 case EXPR_BINARY_NOTEQUAL:
1463                 case EXPR_BINARY_LESS:
1464                 case EXPR_BINARY_LESSEQUAL:
1465                 case EXPR_BINARY_GREATER:
1466                 case EXPR_BINARY_GREATEREQUAL:
1467                 case EXPR_BINARY_BITWISE_AND:
1468                 case EXPR_BINARY_BITWISE_OR:
1469                 case EXPR_BINARY_BITWISE_XOR:
1470                 case EXPR_BINARY_LOGICAL_AND:
1471                 case EXPR_BINARY_LOGICAL_OR:
1472                 case EXPR_BINARY_SHIFTLEFT:
1473                 case EXPR_BINARY_SHIFTRIGHT:
1474                 case EXPR_BINARY_COMMA:
1475                 case EXPR_BINARY_ISGREATER:
1476                 case EXPR_BINARY_ISGREATEREQUAL:
1477                 case EXPR_BINARY_ISLESS:
1478                 case EXPR_BINARY_ISLESSEQUAL:
1479                 case EXPR_BINARY_ISLESSGREATER:
1480                 case EXPR_BINARY_ISUNORDERED:
1481                         mark_vars_read(expr->binary.left,  lhs_ent);
1482                         mark_vars_read(expr->binary.right, lhs_ent);
1483                         return;
1484
1485                 case EXPR_BINARY_ASSIGN:
1486                 case EXPR_BINARY_MUL_ASSIGN:
1487                 case EXPR_BINARY_DIV_ASSIGN:
1488                 case EXPR_BINARY_MOD_ASSIGN:
1489                 case EXPR_BINARY_ADD_ASSIGN:
1490                 case EXPR_BINARY_SUB_ASSIGN:
1491                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:
1492                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:
1493                 case EXPR_BINARY_BITWISE_AND_ASSIGN:
1494                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:
1495                 case EXPR_BINARY_BITWISE_OR_ASSIGN: {
1496                         if (lhs_ent == ENT_ANY)
1497                                 lhs_ent = NULL;
1498                         lhs_ent = determine_lhs_ent(expr->binary.left, lhs_ent);
1499                         mark_vars_read(expr->binary.right, lhs_ent);
1500                         return;
1501                 }
1502
1503                 case EXPR_VA_START:
1504                         determine_lhs_ent(expr->va_starte.ap, lhs_ent);
1505                         return;
1506
1507                 case EXPR_LITERAL_CASES:
1508                 case EXPR_LITERAL_CHARACTER:
1509                 case EXPR_ERROR:
1510                 case EXPR_STRING_LITERAL:
1511                 case EXPR_COMPOUND_LITERAL: // TODO init?
1512                 case EXPR_SIZEOF:
1513                 case EXPR_CLASSIFY_TYPE:
1514                 case EXPR_ALIGNOF:
1515                 case EXPR_FUNCNAME:
1516                 case EXPR_BUILTIN_CONSTANT_P:
1517                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
1518                 case EXPR_OFFSETOF:
1519                 case EXPR_STATEMENT: // TODO
1520                 case EXPR_LABEL_ADDRESS:
1521                 case EXPR_ENUM_CONSTANT:
1522                         return;
1523         }
1524
1525         panic("unhandled expression");
1526 }
1527
1528 static designator_t *parse_designation(void)
1529 {
1530         designator_t  *result = NULL;
1531         designator_t **anchor = &result;
1532
1533         for (;;) {
1534                 designator_t *designator;
1535                 switch (token.kind) {
1536                 case '[':
1537                         designator = allocate_ast_zero(sizeof(designator[0]));
1538                         designator->source_position = *HERE;
1539                         eat('[');
1540                         add_anchor_token(']');
1541                         designator->array_index = parse_constant_expression();
1542                         rem_anchor_token(']');
1543                         expect(']');
1544                         break;
1545                 case '.':
1546                         designator = allocate_ast_zero(sizeof(designator[0]));
1547                         designator->source_position = *HERE;
1548                         eat('.');
1549                         designator->symbol = expect_identifier("while parsing designator", NULL);
1550                         if (!designator->symbol)
1551                                 return NULL;
1552                         break;
1553                 default:
1554                         expect('=');
1555                         return result;
1556                 }
1557
1558                 assert(designator != NULL);
1559                 *anchor = designator;
1560                 anchor  = &designator->next;
1561         }
1562 }
1563
1564 /**
1565  * Build an initializer from a given expression.
1566  */
1567 static initializer_t *initializer_from_expression(type_t *orig_type,
1568                                                   expression_t *expression)
1569 {
1570         /* TODO check that expression is a constant expression */
1571
1572         type_t *const type = skip_typeref(orig_type);
1573
1574         /* §6.7.8.14/15 char array may be initialized by string literals */
1575         if (expression->kind == EXPR_STRING_LITERAL && is_type_array(type)) {
1576                 array_type_t *const array_type   = &type->array;
1577                 type_t       *const element_type = skip_typeref(array_type->element_type);
1578                 switch (expression->string_literal.value.encoding) {
1579                 case STRING_ENCODING_CHAR:
1580                 case STRING_ENCODING_UTF8: {
1581                         if (is_type_atomic(element_type, ATOMIC_TYPE_CHAR)  ||
1582                             is_type_atomic(element_type, ATOMIC_TYPE_SCHAR) ||
1583                             is_type_atomic(element_type, ATOMIC_TYPE_UCHAR)) {
1584                                 goto make_string_init;
1585                         }
1586                         break;
1587                 }
1588
1589                 case STRING_ENCODING_CHAR16:
1590                 case STRING_ENCODING_CHAR32:
1591                 case STRING_ENCODING_WIDE: {
1592                         assert(is_type_pointer(expression->base.type));
1593                         type_t *const init_type = get_unqualified_type(expression->base.type->pointer.points_to);
1594                         if (types_compatible(get_unqualified_type(element_type), init_type)) {
1595 make_string_init:;
1596                                 initializer_t *const init = allocate_initializer_zero(INITIALIZER_STRING);
1597                                 init->value.value = expression;
1598                                 return init;
1599                         }
1600                         break;
1601                 }
1602                 }
1603         }
1604
1605         assign_error_t error = semantic_assign(type, expression);
1606         if (error == ASSIGN_ERROR_INCOMPATIBLE)
1607                 return NULL;
1608         report_assign_error(error, type, expression, "initializer",
1609                             &expression->base.source_position);
1610
1611         initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
1612         result->value.value = create_implicit_cast(expression, type);
1613
1614         return result;
1615 }
1616
1617 /**
1618  * Parses an scalar initializer.
1619  *
1620  * §6.7.8.11; eat {} without warning
1621  */
1622 static initializer_t *parse_scalar_initializer(type_t *type,
1623                                                bool must_be_constant)
1624 {
1625         /* there might be extra {} hierarchies */
1626         int braces = 0;
1627         if (token.kind == '{') {
1628                 warningf(WARN_OTHER, HERE, "extra curly braces around scalar initializer");
1629                 do {
1630                         eat('{');
1631                         ++braces;
1632                 } while (token.kind == '{');
1633         }
1634
1635         expression_t *expression = parse_assignment_expression();
1636         mark_vars_read(expression, NULL);
1637         if (must_be_constant && !is_linker_constant(expression)) {
1638                 errorf(&expression->base.source_position,
1639                        "initialisation expression '%E' is not constant",
1640                        expression);
1641         }
1642
1643         initializer_t *initializer = initializer_from_expression(type, expression);
1644
1645         if (initializer == NULL) {
1646                 errorf(&expression->base.source_position,
1647                        "expression '%E' (type '%T') doesn't match expected type '%T'",
1648                        expression, expression->base.type, type);
1649                 /* TODO */
1650                 return NULL;
1651         }
1652
1653         bool additional_warning_displayed = false;
1654         while (braces > 0) {
1655                 accept(',');
1656                 if (token.kind != '}') {
1657                         if (!additional_warning_displayed) {
1658                                 warningf(WARN_OTHER, HERE, "additional elements in scalar initializer");
1659                                 additional_warning_displayed = true;
1660                         }
1661                 }
1662                 eat_block();
1663                 braces--;
1664         }
1665
1666         return initializer;
1667 }
1668
1669 /**
1670  * An entry in the type path.
1671  */
1672 typedef struct type_path_entry_t type_path_entry_t;
1673 struct type_path_entry_t {
1674         type_t *type;       /**< the upper top type. restored to path->top_tye if this entry is popped. */
1675         union {
1676                 size_t         index;          /**< For array types: the current index. */
1677                 declaration_t *compound_entry; /**< For compound types: the current declaration. */
1678         } v;
1679 };
1680
1681 /**
1682  * A type path expression a position inside compound or array types.
1683  */
1684 typedef struct type_path_t type_path_t;
1685 struct type_path_t {
1686         type_path_entry_t *path;         /**< An flexible array containing the current path. */
1687         type_t            *top_type;     /**< type of the element the path points */
1688         size_t             max_index;    /**< largest index in outermost array */
1689 };
1690
1691 /**
1692  * Prints a type path for debugging.
1693  */
1694 static __attribute__((unused)) void debug_print_type_path(
1695                 const type_path_t *path)
1696 {
1697         size_t len = ARR_LEN(path->path);
1698
1699         for (size_t i = 0; i < len; ++i) {
1700                 const type_path_entry_t *entry = & path->path[i];
1701
1702                 type_t *type = skip_typeref(entry->type);
1703                 if (is_type_compound(type)) {
1704                         /* in gcc mode structs can have no members */
1705                         if (entry->v.compound_entry == NULL) {
1706                                 assert(i == len-1);
1707                                 continue;
1708                         }
1709                         fprintf(stderr, ".%s",
1710                                 entry->v.compound_entry->base.symbol->string);
1711                 } else if (is_type_array(type)) {
1712                         fprintf(stderr, "[%u]", (unsigned) entry->v.index);
1713                 } else {
1714                         fprintf(stderr, "-INVALID-");
1715                 }
1716         }
1717         if (path->top_type != NULL) {
1718                 fprintf(stderr, "  (");
1719                 print_type(path->top_type);
1720                 fprintf(stderr, ")");
1721         }
1722 }
1723
1724 /**
1725  * Return the top type path entry, ie. in a path
1726  * (type).a.b returns the b.
1727  */
1728 static type_path_entry_t *get_type_path_top(const type_path_t *path)
1729 {
1730         size_t len = ARR_LEN(path->path);
1731         assert(len > 0);
1732         return &path->path[len-1];
1733 }
1734
1735 /**
1736  * Enlarge the type path by an (empty) element.
1737  */
1738 static type_path_entry_t *append_to_type_path(type_path_t *path)
1739 {
1740         size_t len = ARR_LEN(path->path);
1741         ARR_RESIZE(type_path_entry_t, path->path, len+1);
1742
1743         type_path_entry_t *result = & path->path[len];
1744         memset(result, 0, sizeof(result[0]));
1745         return result;
1746 }
1747
1748 /**
1749  * Descending into a sub-type. Enter the scope of the current top_type.
1750  */
1751 static void descend_into_subtype(type_path_t *path)
1752 {
1753         type_t *orig_top_type = path->top_type;
1754         type_t *top_type      = skip_typeref(orig_top_type);
1755
1756         type_path_entry_t *top = append_to_type_path(path);
1757         top->type              = top_type;
1758
1759         if (is_type_compound(top_type)) {
1760                 compound_t *const compound = top_type->compound.compound;
1761                 entity_t   *const entry    = skip_unnamed_bitfields(compound->members.entities);
1762
1763                 if (entry != NULL) {
1764                         top->v.compound_entry = &entry->declaration;
1765                         path->top_type = entry->declaration.type;
1766                 } else {
1767                         path->top_type = NULL;
1768                 }
1769         } else if (is_type_array(top_type)) {
1770                 top->v.index   = 0;
1771                 path->top_type = top_type->array.element_type;
1772         } else {
1773                 assert(!is_type_valid(top_type));
1774         }
1775 }
1776
1777 /**
1778  * Pop an entry from the given type path, ie. returning from
1779  * (type).a.b to (type).a
1780  */
1781 static void ascend_from_subtype(type_path_t *path)
1782 {
1783         type_path_entry_t *top = get_type_path_top(path);
1784
1785         path->top_type = top->type;
1786
1787         size_t len = ARR_LEN(path->path);
1788         ARR_RESIZE(type_path_entry_t, path->path, len-1);
1789 }
1790
1791 /**
1792  * Pop entries from the given type path until the given
1793  * path level is reached.
1794  */
1795 static void ascend_to(type_path_t *path, size_t top_path_level)
1796 {
1797         size_t len = ARR_LEN(path->path);
1798
1799         while (len > top_path_level) {
1800                 ascend_from_subtype(path);
1801                 len = ARR_LEN(path->path);
1802         }
1803 }
1804
1805 static bool walk_designator(type_path_t *path, const designator_t *designator,
1806                             bool used_in_offsetof)
1807 {
1808         for (; designator != NULL; designator = designator->next) {
1809                 type_path_entry_t *top       = get_type_path_top(path);
1810                 type_t            *orig_type = top->type;
1811
1812                 type_t *type = skip_typeref(orig_type);
1813
1814                 if (designator->symbol != NULL) {
1815                         symbol_t *symbol = designator->symbol;
1816                         if (!is_type_compound(type)) {
1817                                 if (is_type_valid(type)) {
1818                                         errorf(&designator->source_position,
1819                                                "'.%Y' designator used for non-compound type '%T'",
1820                                                symbol, orig_type);
1821                                 }
1822
1823                                 top->type             = type_error_type;
1824                                 top->v.compound_entry = NULL;
1825                                 orig_type             = type_error_type;
1826                         } else {
1827                                 compound_t *compound = type->compound.compound;
1828                                 entity_t   *iter     = compound->members.entities;
1829                                 for (; iter != NULL; iter = iter->base.next) {
1830                                         if (iter->base.symbol == symbol) {
1831                                                 break;
1832                                         }
1833                                 }
1834                                 if (iter == NULL) {
1835                                         errorf(&designator->source_position,
1836                                                "'%T' has no member named '%Y'", orig_type, symbol);
1837                                         return false;
1838                                 }
1839                                 assert(iter->kind == ENTITY_COMPOUND_MEMBER);
1840                                 if (used_in_offsetof && iter->compound_member.bitfield) {
1841                                         errorf(&designator->source_position,
1842                                                    "offsetof designator '%Y' must not specify bitfield",
1843                                                    symbol);
1844                                         return false;
1845                                 }
1846
1847                                 top->type             = orig_type;
1848                                 top->v.compound_entry = &iter->declaration;
1849                                 orig_type             = iter->declaration.type;
1850                         }
1851                 } else {
1852                         expression_t *array_index = designator->array_index;
1853                         if (is_constant_expression(array_index) != EXPR_CLASS_CONSTANT)
1854                                 return true;
1855
1856                         if (!is_type_array(type)) {
1857                                 if (is_type_valid(type)) {
1858                                         errorf(&designator->source_position,
1859                                                "[%E] designator used for non-array type '%T'",
1860                                                array_index, orig_type);
1861                                 }
1862                                 return false;
1863                         }
1864
1865                         long index = fold_constant_to_int(array_index);
1866                         if (!used_in_offsetof) {
1867                                 if (index < 0) {
1868                                         errorf(&designator->source_position,
1869                                                "array index [%E] must be positive", array_index);
1870                                 } else if (type->array.size_constant) {
1871                                         long array_size = type->array.size;
1872                                         if (index >= array_size) {
1873                                                 errorf(&designator->source_position,
1874                                                        "designator [%E] (%d) exceeds array size %d",
1875                                                        array_index, index, array_size);
1876                                         }
1877                                 }
1878                         }
1879
1880                         top->type    = orig_type;
1881                         top->v.index = (size_t) index;
1882                         orig_type    = type->array.element_type;
1883                 }
1884                 path->top_type = orig_type;
1885
1886                 if (designator->next != NULL) {
1887                         descend_into_subtype(path);
1888                 }
1889         }
1890         return true;
1891 }
1892
1893 static void advance_current_object(type_path_t *path, size_t top_path_level)
1894 {
1895         type_path_entry_t *top = get_type_path_top(path);
1896
1897         type_t *type = skip_typeref(top->type);
1898         if (is_type_union(type)) {
1899                 /* in unions only the first element is initialized */
1900                 top->v.compound_entry = NULL;
1901         } else if (is_type_struct(type)) {
1902                 declaration_t *entry = top->v.compound_entry;
1903
1904                 entity_t *const next_entity = skip_unnamed_bitfields(entry->base.next);
1905                 if (next_entity != NULL) {
1906                         assert(is_declaration(next_entity));
1907                         entry = &next_entity->declaration;
1908                 } else {
1909                         entry = NULL;
1910                 }
1911
1912                 top->v.compound_entry = entry;
1913                 if (entry != NULL) {
1914                         path->top_type = entry->type;
1915                         return;
1916                 }
1917         } else if (is_type_array(type)) {
1918                 assert(is_type_array(type));
1919
1920                 top->v.index++;
1921
1922                 if (!type->array.size_constant || top->v.index < type->array.size) {
1923                         return;
1924                 }
1925         } else {
1926                 assert(!is_type_valid(type));
1927                 return;
1928         }
1929
1930         /* we're past the last member of the current sub-aggregate, try if we
1931          * can ascend in the type hierarchy and continue with another subobject */
1932         size_t len = ARR_LEN(path->path);
1933
1934         if (len > top_path_level) {
1935                 ascend_from_subtype(path);
1936                 advance_current_object(path, top_path_level);
1937         } else {
1938                 path->top_type = NULL;
1939         }
1940 }
1941
1942 /**
1943  * skip any {...} blocks until a closing bracket is reached.
1944  */
1945 static void skip_initializers(void)
1946 {
1947         accept('{');
1948
1949         while (token.kind != '}') {
1950                 if (token.kind == T_EOF)
1951                         return;
1952                 if (token.kind == '{') {
1953                         eat_block();
1954                         continue;
1955                 }
1956                 next_token();
1957         }
1958 }
1959
1960 static initializer_t *create_empty_initializer(void)
1961 {
1962         static initializer_t empty_initializer
1963                 = { .list = { { INITIALIZER_LIST }, 0 } };
1964         return &empty_initializer;
1965 }
1966
1967 /**
1968  * Parse a part of an initialiser for a struct or union,
1969  */
1970 static initializer_t *parse_sub_initializer(type_path_t *path,
1971                 type_t *outer_type, size_t top_path_level,
1972                 parse_initializer_env_t *env)
1973 {
1974         if (token.kind == '}') {
1975                 /* empty initializer */
1976                 return create_empty_initializer();
1977         }
1978
1979         initializer_t *result = NULL;
1980
1981         type_t *orig_type = path->top_type;
1982         type_t *type      = NULL;
1983
1984         if (orig_type == NULL) {
1985                 /* We are initializing an empty compound. */
1986         } else {
1987                 type = skip_typeref(orig_type);
1988         }
1989
1990         initializer_t **initializers = NEW_ARR_F(initializer_t*, 0);
1991
1992         while (true) {
1993                 designator_t *designator = NULL;
1994                 if (token.kind == '.' || token.kind == '[') {
1995                         designator = parse_designation();
1996                         goto finish_designator;
1997                 } else if (token.kind == T_IDENTIFIER && look_ahead(1)->kind == ':') {
1998                         /* GNU-style designator ("identifier: value") */
1999                         designator = allocate_ast_zero(sizeof(designator[0]));
2000                         designator->source_position = *HERE;
2001                         designator->symbol          = token.base.symbol;
2002                         eat(T_IDENTIFIER);
2003                         eat(':');
2004
2005 finish_designator:
2006                         /* reset path to toplevel, evaluate designator from there */
2007                         ascend_to(path, top_path_level);
2008                         if (!walk_designator(path, designator, false)) {
2009                                 /* can't continue after designation error */
2010                                 goto end_error;
2011                         }
2012
2013                         initializer_t *designator_initializer
2014                                 = allocate_initializer_zero(INITIALIZER_DESIGNATOR);
2015                         designator_initializer->designator.designator = designator;
2016                         ARR_APP1(initializer_t*, initializers, designator_initializer);
2017
2018                         orig_type = path->top_type;
2019                         type      = orig_type != NULL ? skip_typeref(orig_type) : NULL;
2020                 }
2021
2022                 initializer_t *sub;
2023
2024                 if (token.kind == '{') {
2025                         if (type != NULL && is_type_scalar(type)) {
2026                                 sub = parse_scalar_initializer(type, env->must_be_constant);
2027                         } else {
2028                                 if (type == NULL) {
2029                                         if (env->entity != NULL) {
2030                                                 errorf(HERE, "extra brace group at end of initializer for '%N'", env->entity);
2031                                         } else {
2032                                                 errorf(HERE, "extra brace group at end of initializer");
2033                                         }
2034                                         eat('{');
2035                                 } else {
2036                                         eat('{');
2037                                         descend_into_subtype(path);
2038                                 }
2039
2040                                 add_anchor_token('}');
2041                                 sub = parse_sub_initializer(path, orig_type, top_path_level+1,
2042                                                             env);
2043                                 rem_anchor_token('}');
2044
2045                                 expect('}');
2046
2047                                 if (!type)
2048                                         goto error_parse_next;
2049
2050                                 ascend_from_subtype(path);
2051                         }
2052                 } else {
2053                         /* must be an expression */
2054                         expression_t *expression = parse_assignment_expression();
2055                         mark_vars_read(expression, NULL);
2056
2057                         if (env->must_be_constant && !is_linker_constant(expression)) {
2058                                 errorf(&expression->base.source_position,
2059                                        "Initialisation expression '%E' is not constant",
2060                                        expression);
2061                         }
2062
2063                         if (type == NULL) {
2064                                 /* we are already outside, ... */
2065                                 if (outer_type == NULL)
2066                                         goto error_parse_next;
2067                                 type_t *const outer_type_skip = skip_typeref(outer_type);
2068                                 if (is_type_compound(outer_type_skip) &&
2069                                                 !outer_type_skip->compound.compound->complete) {
2070                                         goto error_parse_next;
2071                                 }
2072
2073                                 source_position_t const* const pos = &expression->base.source_position;
2074                                 if (env->entity != NULL) {
2075                                         warningf(WARN_OTHER, pos, "excess elements in initializer for '%N'", env->entity);
2076                                 } else {
2077                                         warningf(WARN_OTHER, pos, "excess elements in initializer");
2078                                 }
2079                                 goto error_parse_next;
2080                         }
2081
2082                         /* handle { "string" } special case */
2083                         if (expression->kind == EXPR_STRING_LITERAL && outer_type != NULL) {
2084                                 result = initializer_from_expression(outer_type, expression);
2085                                 if (result != NULL) {
2086                                         accept(',');
2087                                         if (token.kind != '}') {
2088                                                 warningf(WARN_OTHER, HERE, "excessive elements in initializer for type '%T'", outer_type);
2089                                         }
2090                                         /* TODO: eat , ... */
2091                                         goto out;
2092                                 }
2093                         }
2094
2095                         /* descend into subtypes until expression matches type */
2096                         while (true) {
2097                                 orig_type = path->top_type;
2098                                 type      = skip_typeref(orig_type);
2099
2100                                 sub = initializer_from_expression(orig_type, expression);
2101                                 if (sub != NULL) {
2102                                         break;
2103                                 }
2104                                 if (!is_type_valid(type)) {
2105                                         goto end_error;
2106                                 }
2107                                 if (is_type_scalar(type)) {
2108                                         errorf(&expression->base.source_position,
2109                                                         "expression '%E' doesn't match expected type '%T'",
2110                                                         expression, orig_type);
2111                                         goto end_error;
2112                                 }
2113
2114                                 descend_into_subtype(path);
2115                         }
2116                 }
2117
2118                 /* update largest index of top array */
2119                 const type_path_entry_t *first      = &path->path[0];
2120                 type_t                  *first_type = first->type;
2121                 first_type                          = skip_typeref(first_type);
2122                 if (is_type_array(first_type)) {
2123                         size_t index = first->v.index;
2124                         if (index > path->max_index)
2125                                 path->max_index = index;
2126                 }
2127
2128                 /* append to initializers list */
2129                 ARR_APP1(initializer_t*, initializers, sub);
2130
2131 error_parse_next:
2132                 if (!accept(','))
2133                         break;
2134                 if (token.kind == '}') {
2135                         break;
2136                 }
2137
2138                 if (type != NULL) {
2139                         /* advance to the next declaration if we are not at the end */
2140                         advance_current_object(path, top_path_level);
2141                         orig_type = path->top_type;
2142                         if (orig_type != NULL)
2143                                 type = skip_typeref(orig_type);
2144                         else
2145                                 type = NULL;
2146                 }
2147         }
2148
2149         size_t len  = ARR_LEN(initializers);
2150         size_t size = sizeof(initializer_list_t) + len * sizeof(initializers[0]);
2151         result = allocate_ast_zero(size);
2152         result->kind     = INITIALIZER_LIST;
2153         result->list.len = len;
2154         memcpy(&result->list.initializers, initializers,
2155                len * sizeof(initializers[0]));
2156         goto out;
2157
2158 end_error:
2159         skip_initializers();
2160 out:
2161         DEL_ARR_F(initializers);
2162         ascend_to(path, top_path_level+1);
2163         return result;
2164 }
2165
2166 static expression_t *make_size_literal(size_t value)
2167 {
2168         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_INTEGER);
2169         literal->base.type    = type_size_t;
2170
2171         char buf[128];
2172         snprintf(buf, sizeof(buf), "%u", (unsigned) value);
2173         literal->literal.value = make_string(buf);
2174
2175         return literal;
2176 }
2177
2178 /**
2179  * Parses an initializer. Parsers either a compound literal
2180  * (env->declaration == NULL) or an initializer of a declaration.
2181  */
2182 static initializer_t *parse_initializer(parse_initializer_env_t *env)
2183 {
2184         type_t        *type      = skip_typeref(env->type);
2185         size_t         max_index = 0;
2186         initializer_t *result;
2187
2188         if (is_type_scalar(type)) {
2189                 result = parse_scalar_initializer(type, env->must_be_constant);
2190         } else if (token.kind == '{') {
2191                 eat('{');
2192
2193                 type_path_t path;
2194                 memset(&path, 0, sizeof(path));
2195                 path.top_type = env->type;
2196                 path.path     = NEW_ARR_F(type_path_entry_t, 0);
2197
2198                 descend_into_subtype(&path);
2199
2200                 add_anchor_token('}');
2201                 result = parse_sub_initializer(&path, env->type, 1, env);
2202                 rem_anchor_token('}');
2203
2204                 max_index = path.max_index;
2205                 DEL_ARR_F(path.path);
2206
2207                 expect('}');
2208         } else {
2209                 /* parse_scalar_initializer() also works in this case: we simply
2210                  * have an expression without {} around it */
2211                 result = parse_scalar_initializer(type, env->must_be_constant);
2212         }
2213
2214         /* §6.7.8:22 array initializers for arrays with unknown size determine
2215          * the array type size */
2216         if (is_type_array(type) && type->array.size_expression == NULL
2217                         && result != NULL) {
2218                 size_t size;
2219                 switch (result->kind) {
2220                 case INITIALIZER_LIST:
2221                         assert(max_index != 0xdeadbeaf);
2222                         size = max_index + 1;
2223                         break;
2224
2225                 case INITIALIZER_STRING: {
2226                         size = get_string_len(&get_init_string(result)->value) + 1;
2227                         break;
2228                 }
2229
2230                 case INITIALIZER_DESIGNATOR:
2231                 case INITIALIZER_VALUE:
2232                         /* can happen for parse errors */
2233                         size = 0;
2234                         break;
2235
2236                 default:
2237                         internal_errorf(HERE, "invalid initializer type");
2238                 }
2239
2240                 type_t *new_type = duplicate_type(type);
2241
2242                 new_type->array.size_expression   = make_size_literal(size);
2243                 new_type->array.size_constant     = true;
2244                 new_type->array.has_implicit_size = true;
2245                 new_type->array.size              = size;
2246                 env->type = new_type;
2247         }
2248
2249         return result;
2250 }
2251
2252 static void append_entity(scope_t *scope, entity_t *entity)
2253 {
2254         if (scope->last_entity != NULL) {
2255                 scope->last_entity->base.next = entity;
2256         } else {
2257                 scope->entities = entity;
2258         }
2259         entity->base.parent_entity = current_entity;
2260         scope->last_entity         = entity;
2261 }
2262
2263
2264 static compound_t *parse_compound_type_specifier(bool is_struct)
2265 {
2266         source_position_t const pos = *HERE;
2267         eat(is_struct ? T_struct : T_union);
2268
2269         symbol_t    *symbol     = NULL;
2270         entity_t    *entity     = NULL;
2271         attribute_t *attributes = NULL;
2272
2273         if (token.kind == T___attribute__) {
2274                 attributes = parse_attributes(NULL);
2275         }
2276
2277         entity_kind_tag_t const kind = is_struct ? ENTITY_STRUCT : ENTITY_UNION;
2278         if (token.kind == T_IDENTIFIER) {
2279                 /* the compound has a name, check if we have seen it already */
2280                 symbol = token.base.symbol;
2281                 entity = get_tag(symbol, kind);
2282                 eat(T_IDENTIFIER);
2283
2284                 if (entity != NULL) {
2285                         if (entity->base.parent_scope != current_scope &&
2286                             (token.kind == '{' || token.kind == ';')) {
2287                                 /* we're in an inner scope and have a definition. Shadow
2288                                  * existing definition in outer scope */
2289                                 entity = NULL;
2290                         } else if (entity->compound.complete && token.kind == '{') {
2291                                 source_position_t const *const ppos = &entity->base.source_position;
2292                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2293                                 /* clear members in the hope to avoid further errors */
2294                                 entity->compound.members.entities = NULL;
2295                         }
2296                 }
2297         } else if (token.kind != '{') {
2298                 char const *const msg =
2299                         is_struct ? "while parsing struct type specifier" :
2300                                     "while parsing union type specifier";
2301                 parse_error_expected(msg, T_IDENTIFIER, '{', NULL);
2302
2303                 return NULL;
2304         }
2305
2306         if (entity == NULL) {
2307                 entity = allocate_entity_zero(kind, NAMESPACE_TAG, symbol, &pos);
2308                 entity->compound.alignment = 1;
2309                 entity->base.parent_scope  = current_scope;
2310                 if (symbol != NULL) {
2311                         environment_push(entity);
2312                 }
2313                 append_entity(current_scope, entity);
2314         }
2315
2316         if (token.kind == '{') {
2317                 parse_compound_type_entries(&entity->compound);
2318
2319                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2320                 if (symbol == NULL) {
2321                         assert(anonymous_entity == NULL);
2322                         anonymous_entity = entity;
2323                 }
2324         }
2325
2326         if (attributes != NULL) {
2327                 entity->compound.attributes = attributes;
2328                 handle_entity_attributes(attributes, entity);
2329         }
2330
2331         return &entity->compound;
2332 }
2333
2334 static void parse_enum_entries(type_t *const enum_type)
2335 {
2336         eat('{');
2337
2338         if (token.kind == '}') {
2339                 errorf(HERE, "empty enum not allowed");
2340                 eat('}');
2341                 return;
2342         }
2343
2344         add_anchor_token('}');
2345         add_anchor_token(',');
2346         do {
2347                 add_anchor_token('=');
2348                 source_position_t pos;
2349                 symbol_t *const symbol = expect_identifier("while parsing enum entry", &pos);
2350                 entity_t *const entity = allocate_entity_zero(ENTITY_ENUM_VALUE, NAMESPACE_NORMAL, symbol, &pos);
2351                 entity->enum_value.enum_type = enum_type;
2352                 rem_anchor_token('=');
2353
2354                 if (accept('=')) {
2355                         expression_t *value = parse_constant_expression();
2356
2357                         value = create_implicit_cast(value, enum_type);
2358                         entity->enum_value.value = value;
2359
2360                         /* TODO semantic */
2361                 }
2362
2363                 record_entity(entity, false);
2364         } while (accept(',') && token.kind != '}');
2365         rem_anchor_token(',');
2366         rem_anchor_token('}');
2367
2368         expect('}');
2369 }
2370
2371 static type_t *parse_enum_specifier(void)
2372 {
2373         source_position_t const pos = *HERE;
2374         entity_t               *entity;
2375         symbol_t               *symbol;
2376
2377         eat(T_enum);
2378         switch (token.kind) {
2379                 case T_IDENTIFIER:
2380                         symbol = token.base.symbol;
2381                         entity = get_tag(symbol, ENTITY_ENUM);
2382                         eat(T_IDENTIFIER);
2383
2384                         if (entity != NULL) {
2385                                 if (entity->base.parent_scope != current_scope &&
2386                                                 (token.kind == '{' || token.kind == ';')) {
2387                                         /* we're in an inner scope and have a definition. Shadow
2388                                          * existing definition in outer scope */
2389                                         entity = NULL;
2390                                 } else if (entity->enume.complete && token.kind == '{') {
2391                                         source_position_t const *const ppos = &entity->base.source_position;
2392                                         errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2393                                 }
2394                         }
2395                         break;
2396
2397                 case '{':
2398                         entity = NULL;
2399                         symbol = NULL;
2400                         break;
2401
2402                 default:
2403                         parse_error_expected("while parsing enum type specifier",
2404                                         T_IDENTIFIER, '{', NULL);
2405                         return NULL;
2406         }
2407
2408         if (entity == NULL) {
2409                 entity = allocate_entity_zero(ENTITY_ENUM, NAMESPACE_TAG, symbol, &pos);
2410                 entity->base.parent_scope = current_scope;
2411         }
2412
2413         type_t *const type     = allocate_type_zero(TYPE_ENUM);
2414         type->enumt.enume      = &entity->enume;
2415         type->enumt.base.akind = ATOMIC_TYPE_INT;
2416
2417         if (token.kind == '{') {
2418                 if (symbol != NULL) {
2419                         environment_push(entity);
2420                 }
2421                 append_entity(current_scope, entity);
2422                 entity->enume.complete = true;
2423
2424                 parse_enum_entries(type);
2425                 parse_attributes(NULL);
2426
2427                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2428                 if (symbol == NULL) {
2429                         assert(anonymous_entity == NULL);
2430                         anonymous_entity = entity;
2431                 }
2432         } else if (!entity->enume.complete && !(c_mode & _GNUC)) {
2433                 errorf(HERE, "'%T' used before definition (incomplete enums are a GNU extension)", type);
2434         }
2435
2436         return type;
2437 }
2438
2439 /**
2440  * if a symbol is a typedef to another type, return true
2441  */
2442 static bool is_typedef_symbol(symbol_t *symbol)
2443 {
2444         const entity_t *const entity = get_entity(symbol, NAMESPACE_NORMAL);
2445         return entity != NULL && entity->kind == ENTITY_TYPEDEF;
2446 }
2447
2448 static type_t *parse_typeof(void)
2449 {
2450         eat(T___typeof__);
2451
2452         type_t *type;
2453
2454         add_anchor_token(')');
2455         expect('(');
2456
2457         expression_t *expression  = NULL;
2458
2459         switch (token.kind) {
2460         case T_IDENTIFIER:
2461                 if (is_typedef_symbol(token.base.symbol)) {
2462         DECLARATION_START
2463                         type = parse_typename();
2464                 } else {
2465         default:
2466                         expression = parse_expression();
2467                         type       = revert_automatic_type_conversion(expression);
2468                 }
2469                 break;
2470         }
2471
2472         rem_anchor_token(')');
2473         expect(')');
2474
2475         type_t *typeof_type              = allocate_type_zero(TYPE_TYPEOF);
2476         typeof_type->typeoft.expression  = expression;
2477         typeof_type->typeoft.typeof_type = type;
2478
2479         return typeof_type;
2480 }
2481
2482 typedef enum specifiers_t {
2483         SPECIFIER_NONE      = 0,
2484         SPECIFIER_SIGNED    = 1 << 0,
2485         SPECIFIER_UNSIGNED  = 1 << 1,
2486         SPECIFIER_LONG      = 1 << 2,
2487         SPECIFIER_INT       = 1 << 3,
2488         SPECIFIER_DOUBLE    = 1 << 4,
2489         SPECIFIER_CHAR      = 1 << 5,
2490         SPECIFIER_WCHAR_T   = 1 << 6,
2491         SPECIFIER_SHORT     = 1 << 7,
2492         SPECIFIER_LONG_LONG = 1 << 8,
2493         SPECIFIER_FLOAT     = 1 << 9,
2494         SPECIFIER_BOOL      = 1 << 10,
2495         SPECIFIER_VOID      = 1 << 11,
2496         SPECIFIER_INT8      = 1 << 12,
2497         SPECIFIER_INT16     = 1 << 13,
2498         SPECIFIER_INT32     = 1 << 14,
2499         SPECIFIER_INT64     = 1 << 15,
2500         SPECIFIER_INT128    = 1 << 16,
2501         SPECIFIER_COMPLEX   = 1 << 17,
2502         SPECIFIER_IMAGINARY = 1 << 18,
2503 } specifiers_t;
2504
2505 static type_t *get_typedef_type(symbol_t *symbol)
2506 {
2507         entity_t *entity = get_entity(symbol, NAMESPACE_NORMAL);
2508         if (entity == NULL || entity->kind != ENTITY_TYPEDEF)
2509                 return NULL;
2510
2511         type_t *type            = allocate_type_zero(TYPE_TYPEDEF);
2512         type->typedeft.typedefe = &entity->typedefe;
2513
2514         return type;
2515 }
2516
2517 static attribute_t *parse_attribute_ms_property(attribute_t *attribute)
2518 {
2519         attribute_property_argument_t *const property = allocate_ast_zero(sizeof(*property));
2520
2521         add_anchor_token(')');
2522         add_anchor_token(',');
2523         expect('(');
2524
2525         do {
2526                 add_anchor_token('=');
2527                 source_position_t pos;
2528                 symbol_t *const prop_sym = expect_identifier("while parsing property declspec", &pos);
2529                 rem_anchor_token('=');
2530
2531                 symbol_t **prop = NULL;
2532                 if (prop_sym) {
2533                         if (streq(prop_sym->string, "put")) {
2534                                 prop = &property->put_symbol;
2535                         } else if (streq(prop_sym->string, "get")) {
2536                                 prop = &property->get_symbol;
2537                         } else {
2538                                 errorf(&pos, "expected put or get in property declspec, but got '%Y'", prop_sym);
2539                         }
2540                 }
2541
2542                 add_anchor_token(T_IDENTIFIER);
2543                 expect('=');
2544                 rem_anchor_token(T_IDENTIFIER);
2545
2546                 symbol_t *const sym = expect_identifier("while parsing property declspec", NULL);
2547                 if (prop != NULL)
2548                         *prop = sym ? sym : sym_anonymous;
2549         } while (accept(','));
2550         rem_anchor_token(',');
2551         rem_anchor_token(')');
2552
2553         attribute->a.property = property;
2554
2555         expect(')');
2556         return attribute;
2557 }
2558
2559 static attribute_t *parse_microsoft_extended_decl_modifier_single(void)
2560 {
2561         attribute_kind_t kind = ATTRIBUTE_UNKNOWN;
2562         if (accept(T_restrict)) {
2563                 kind = ATTRIBUTE_MS_RESTRICT;
2564         } else if (token.kind == T_IDENTIFIER) {
2565                 char const *const name = token.base.symbol->string;
2566                 for (attribute_kind_t k = ATTRIBUTE_MS_FIRST; k <= ATTRIBUTE_MS_LAST;
2567                      ++k) {
2568                         const char *attribute_name = get_attribute_name(k);
2569                         if (attribute_name != NULL && streq(attribute_name, name)) {
2570                                 kind = k;
2571                                 break;
2572                         }
2573                 }
2574
2575                 if (kind == ATTRIBUTE_UNKNOWN) {
2576                         warningf(WARN_ATTRIBUTE, HERE, "unknown __declspec '%s' ignored", name);
2577                 }
2578         } else {
2579                 parse_error_expected("while parsing __declspec", T_IDENTIFIER, NULL);
2580                 return NULL;
2581         }
2582
2583         attribute_t *attribute = allocate_attribute_zero(kind);
2584         eat(T_IDENTIFIER);
2585
2586         if (kind == ATTRIBUTE_MS_PROPERTY) {
2587                 return parse_attribute_ms_property(attribute);
2588         }
2589
2590         /* parse arguments */
2591         if (accept('('))
2592                 attribute->a.arguments = parse_attribute_arguments();
2593
2594         return attribute;
2595 }
2596
2597 static attribute_t *parse_microsoft_extended_decl_modifier(attribute_t *first)
2598 {
2599         eat(T__declspec);
2600
2601         add_anchor_token(')');
2602         expect('(');
2603         if (token.kind != ')') {
2604                 attribute_t **anchor = &first;
2605                 do {
2606                         while (*anchor != NULL)
2607                                 anchor = &(*anchor)->next;
2608
2609                         attribute_t *attribute
2610                                 = parse_microsoft_extended_decl_modifier_single();
2611                         if (attribute == NULL)
2612                                 break;
2613
2614                         *anchor = attribute;
2615                         anchor  = &attribute->next;
2616                 } while (accept(','));
2617         }
2618         rem_anchor_token(')');
2619         expect(')');
2620         return first;
2621 }
2622
2623 static entity_t *create_error_entity(symbol_t *symbol, entity_kind_tag_t kind)
2624 {
2625         entity_t *const entity = allocate_entity_zero(kind, NAMESPACE_NORMAL, symbol, HERE);
2626         if (is_declaration(entity)) {
2627                 entity->declaration.type     = type_error_type;
2628                 entity->declaration.implicit = true;
2629         } else if (kind == ENTITY_TYPEDEF) {
2630                 entity->typedefe.type    = type_error_type;
2631                 entity->typedefe.builtin = true;
2632         }
2633         if (kind != ENTITY_COMPOUND_MEMBER)
2634                 record_entity(entity, false);
2635         return entity;
2636 }
2637
2638 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
2639 {
2640         type_t            *type            = NULL;
2641         type_qualifiers_t  qualifiers      = TYPE_QUALIFIER_NONE;
2642         unsigned           type_specifiers = 0;
2643         bool               newtype         = false;
2644         bool               saw_error       = false;
2645
2646         memset(specifiers, 0, sizeof(*specifiers));
2647         specifiers->source_position = *HERE;
2648
2649         while (true) {
2650                 specifiers->attributes = parse_attributes(specifiers->attributes);
2651
2652                 switch (token.kind) {
2653                 /* storage class */
2654 #define MATCH_STORAGE_CLASS(token, class)                                  \
2655                 case token:                                                        \
2656                         if (specifiers->storage_class != STORAGE_CLASS_NONE) {         \
2657                                 errorf(HERE, "multiple storage classes in declaration specifiers"); \
2658                         }                                                              \
2659                         specifiers->storage_class = class;                             \
2660                         if (specifiers->thread_local)                                  \
2661                                 goto check_thread_storage_class;                           \
2662                         eat(token); \
2663                         break;
2664
2665                 MATCH_STORAGE_CLASS(T_typedef,  STORAGE_CLASS_TYPEDEF)
2666                 MATCH_STORAGE_CLASS(T_extern,   STORAGE_CLASS_EXTERN)
2667                 MATCH_STORAGE_CLASS(T_static,   STORAGE_CLASS_STATIC)
2668                 MATCH_STORAGE_CLASS(T_auto,     STORAGE_CLASS_AUTO)
2669                 MATCH_STORAGE_CLASS(T_register, STORAGE_CLASS_REGISTER)
2670
2671                 case T__declspec:
2672                         specifiers->attributes
2673                                 = parse_microsoft_extended_decl_modifier(specifiers->attributes);
2674                         break;
2675
2676                 case T__Thread_local:
2677                         if (specifiers->thread_local) {
2678                                 errorf(HERE, "duplicate %K", &token);
2679                         } else {
2680                                 specifiers->thread_local = true;
2681 check_thread_storage_class:
2682                                 switch (specifiers->storage_class) {
2683                                         case STORAGE_CLASS_EXTERN:
2684                                         case STORAGE_CLASS_NONE:
2685                                         case STORAGE_CLASS_STATIC:
2686                                                 break;
2687
2688                                                 char const* wrong;
2689                                         case STORAGE_CLASS_AUTO:     wrong = "auto";     goto wrong_thread_storage_class;
2690                                         case STORAGE_CLASS_REGISTER: wrong = "register"; goto wrong_thread_storage_class;
2691                                         case STORAGE_CLASS_TYPEDEF:  wrong = "typedef";  goto wrong_thread_storage_class;
2692 wrong_thread_storage_class:
2693                                                 errorf(HERE, "%K used with '%s'", &token, wrong);
2694                                                 break;
2695                                 }
2696                         }
2697                         next_token();
2698                         break;
2699
2700                 /* type qualifiers */
2701 #define MATCH_TYPE_QUALIFIER(token, qualifier)                          \
2702                 case token:                                                     \
2703                         qualifiers |= qualifier;                                    \
2704                         eat(token); \
2705                         break
2706
2707                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
2708                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
2709                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
2710                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
2711                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
2712                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
2713                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
2714                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
2715
2716                 /* type specifiers */
2717 #define MATCH_SPECIFIER(token, specifier, name)                         \
2718                 case token:                                                     \
2719                         if (type_specifiers & specifier) {                           \
2720                                 errorf(HERE, "multiple " name " type specifiers given"); \
2721                         } else {                                                    \
2722                                 type_specifiers |= specifier;                           \
2723                         }                                                           \
2724                         eat(token); \
2725                         break
2726
2727                 MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool");
2728                 MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex");
2729                 MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary");
2730                 MATCH_SPECIFIER(T__int128,    SPECIFIER_INT128,    "_int128");
2731                 MATCH_SPECIFIER(T__int16,     SPECIFIER_INT16,     "_int16");
2732                 MATCH_SPECIFIER(T__int32,     SPECIFIER_INT32,     "_int32");
2733                 MATCH_SPECIFIER(T__int64,     SPECIFIER_INT64,     "_int64");
2734                 MATCH_SPECIFIER(T__int8,      SPECIFIER_INT8,      "_int8");
2735                 MATCH_SPECIFIER(T_bool,       SPECIFIER_BOOL,      "bool");
2736                 MATCH_SPECIFIER(T_char,       SPECIFIER_CHAR,      "char");
2737                 MATCH_SPECIFIER(T_double,     SPECIFIER_DOUBLE,    "double");
2738                 MATCH_SPECIFIER(T_float,      SPECIFIER_FLOAT,     "float");
2739                 MATCH_SPECIFIER(T_int,        SPECIFIER_INT,       "int");
2740                 MATCH_SPECIFIER(T_short,      SPECIFIER_SHORT,     "short");
2741                 MATCH_SPECIFIER(T_signed,     SPECIFIER_SIGNED,    "signed");
2742                 MATCH_SPECIFIER(T_unsigned,   SPECIFIER_UNSIGNED,  "unsigned");
2743                 MATCH_SPECIFIER(T_void,       SPECIFIER_VOID,      "void");
2744                 MATCH_SPECIFIER(T_wchar_t,    SPECIFIER_WCHAR_T,   "wchar_t");
2745
2746                 case T_inline:
2747                         eat(T_inline);
2748                         specifiers->is_inline = true;
2749                         break;
2750
2751 #if 0
2752                 case T__forceinline:
2753                         eat(T__forceinline);
2754                         specifiers->modifiers |= DM_FORCEINLINE;
2755                         break;
2756 #endif
2757
2758                 case T_long:
2759                         if (type_specifiers & SPECIFIER_LONG_LONG) {
2760                                 errorf(HERE, "too many long type specifiers given");
2761                         } else if (type_specifiers & SPECIFIER_LONG) {
2762                                 type_specifiers |= SPECIFIER_LONG_LONG;
2763                         } else {
2764                                 type_specifiers |= SPECIFIER_LONG;
2765                         }
2766                         eat(T_long);
2767                         break;
2768
2769 #define CHECK_DOUBLE_TYPE() \
2770         (type != NULL ? errorf(HERE, "multiple types in declaration specifiers") : (void)0)
2771
2772                 case T_struct:
2773                         CHECK_DOUBLE_TYPE();
2774                         type = allocate_type_zero(TYPE_COMPOUND_STRUCT);
2775
2776                         type->compound.compound = parse_compound_type_specifier(true);
2777                         break;
2778                 case T_union:
2779                         CHECK_DOUBLE_TYPE();
2780                         type = allocate_type_zero(TYPE_COMPOUND_UNION);
2781                         type->compound.compound = parse_compound_type_specifier(false);
2782                         break;
2783                 case T_enum:
2784                         CHECK_DOUBLE_TYPE();
2785                         type = parse_enum_specifier();
2786                         break;
2787                 case T___typeof__:
2788                         CHECK_DOUBLE_TYPE();
2789                         type = parse_typeof();
2790                         break;
2791                 case T___builtin_va_list:
2792                         CHECK_DOUBLE_TYPE();
2793                         type = duplicate_type(type_valist);
2794                         eat(T___builtin_va_list);
2795                         break;
2796
2797                 case T_IDENTIFIER: {
2798                         /* only parse identifier if we haven't found a type yet */
2799                         if (type != NULL || type_specifiers != 0) {
2800                                 /* Be somewhat resilient to typos like 'unsigned lng* f()' in a
2801                                  * declaration, so it doesn't generate errors about expecting '(' or
2802                                  * '{' later on. */
2803                                 switch (look_ahead(1)->kind) {
2804                                         STORAGE_CLASSES
2805                                         TYPE_SPECIFIERS
2806                                         case T_const:
2807                                         case T_restrict:
2808                                         case T_volatile:
2809                                         case T_inline:
2810                                         case T__forceinline: /* ^ DECLARATION_START except for __attribute__ */
2811                                         case T_IDENTIFIER:
2812                                         case '&':
2813                                         case '*':
2814                                                 errorf(HERE, "discarding stray %K in declaration specifier", &token);
2815                                                 eat(T_IDENTIFIER);
2816                                                 continue;
2817
2818                                         default:
2819                                                 goto finish_specifiers;
2820                                 }
2821                         }
2822
2823                         type_t *const typedef_type = get_typedef_type(token.base.symbol);
2824                         if (typedef_type == NULL) {
2825                                 /* Be somewhat resilient to typos like 'vodi f()' at the beginning of a
2826                                  * declaration, so it doesn't generate 'implicit int' followed by more
2827                                  * errors later on. */
2828                                 token_kind_t const la1_type = (token_kind_t)look_ahead(1)->kind;
2829                                 switch (la1_type) {
2830                                         DECLARATION_START
2831                                         case T_IDENTIFIER:
2832                                         case '&':
2833                                         case '*': {
2834                                                 errorf(HERE, "%K does not name a type", &token);
2835
2836                                                 entity_t *const entity = create_error_entity(token.base.symbol, ENTITY_TYPEDEF);
2837
2838                                                 type = allocate_type_zero(TYPE_TYPEDEF);
2839                                                 type->typedeft.typedefe = &entity->typedefe;
2840
2841                                                 eat(T_IDENTIFIER);
2842                                                 saw_error = true;
2843                                                 continue;
2844                                         }
2845
2846                                         default:
2847                                                 goto finish_specifiers;
2848                                 }
2849                         }
2850
2851                         eat(T_IDENTIFIER);
2852                         type = typedef_type;
2853                         break;
2854                 }
2855
2856                 /* function specifier */
2857                 default:
2858                         goto finish_specifiers;
2859                 }
2860         }
2861
2862 finish_specifiers:
2863         specifiers->attributes = parse_attributes(specifiers->attributes);
2864
2865         if (type == NULL || (saw_error && type_specifiers != 0)) {
2866                 atomic_type_kind_t atomic_type;
2867
2868                 /* match valid basic types */
2869                 switch (type_specifiers) {
2870                 case SPECIFIER_VOID:
2871                         atomic_type = ATOMIC_TYPE_VOID;
2872                         break;
2873                 case SPECIFIER_WCHAR_T:
2874                         atomic_type = ATOMIC_TYPE_WCHAR_T;
2875                         break;
2876                 case SPECIFIER_CHAR:
2877                         atomic_type = ATOMIC_TYPE_CHAR;
2878                         break;
2879                 case SPECIFIER_SIGNED | SPECIFIER_CHAR:
2880                         atomic_type = ATOMIC_TYPE_SCHAR;
2881                         break;
2882                 case SPECIFIER_UNSIGNED | SPECIFIER_CHAR:
2883                         atomic_type = ATOMIC_TYPE_UCHAR;
2884                         break;
2885                 case SPECIFIER_SHORT:
2886                 case SPECIFIER_SIGNED | SPECIFIER_SHORT:
2887                 case SPECIFIER_SHORT | SPECIFIER_INT:
2888                 case SPECIFIER_SIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2889                         atomic_type = ATOMIC_TYPE_SHORT;
2890                         break;
2891                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT:
2892                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2893                         atomic_type = ATOMIC_TYPE_USHORT;
2894                         break;
2895                 case SPECIFIER_INT:
2896                 case SPECIFIER_SIGNED:
2897                 case SPECIFIER_SIGNED | SPECIFIER_INT:
2898                         atomic_type = ATOMIC_TYPE_INT;
2899                         break;
2900                 case SPECIFIER_UNSIGNED:
2901                 case SPECIFIER_UNSIGNED | SPECIFIER_INT:
2902                         atomic_type = ATOMIC_TYPE_UINT;
2903                         break;
2904                 case SPECIFIER_LONG:
2905                 case SPECIFIER_SIGNED | SPECIFIER_LONG:
2906                 case SPECIFIER_LONG | SPECIFIER_INT:
2907                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2908                         atomic_type = ATOMIC_TYPE_LONG;
2909                         break;
2910                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:
2911                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2912                         atomic_type = ATOMIC_TYPE_ULONG;
2913                         break;
2914
2915                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2916                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2917                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG | SPECIFIER_INT:
2918                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2919                         | SPECIFIER_INT:
2920                         atomic_type = ATOMIC_TYPE_LONGLONG;
2921                         goto warn_about_long_long;
2922
2923                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2924                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2925                         | SPECIFIER_INT:
2926                         atomic_type = ATOMIC_TYPE_ULONGLONG;
2927 warn_about_long_long:
2928                         warningf(WARN_LONG_LONG, &specifiers->source_position, "ISO C90 does not support 'long long'");
2929                         break;
2930
2931                 case SPECIFIER_UNSIGNED | SPECIFIER_INT8:
2932                         atomic_type = unsigned_int8_type_kind;
2933                         break;
2934
2935                 case SPECIFIER_UNSIGNED | SPECIFIER_INT16:
2936                         atomic_type = unsigned_int16_type_kind;
2937                         break;
2938
2939                 case SPECIFIER_UNSIGNED | SPECIFIER_INT32:
2940                         atomic_type = unsigned_int32_type_kind;
2941                         break;
2942
2943                 case SPECIFIER_UNSIGNED | SPECIFIER_INT64:
2944                         atomic_type = unsigned_int64_type_kind;
2945                         break;
2946
2947                 case SPECIFIER_UNSIGNED | SPECIFIER_INT128:
2948                         atomic_type = unsigned_int128_type_kind;
2949                         break;
2950
2951                 case SPECIFIER_INT8:
2952                 case SPECIFIER_SIGNED | SPECIFIER_INT8:
2953                         atomic_type = int8_type_kind;
2954                         break;
2955
2956                 case SPECIFIER_INT16:
2957                 case SPECIFIER_SIGNED | SPECIFIER_INT16:
2958                         atomic_type = int16_type_kind;
2959                         break;
2960
2961                 case SPECIFIER_INT32:
2962                 case SPECIFIER_SIGNED | SPECIFIER_INT32:
2963                         atomic_type = int32_type_kind;
2964                         break;
2965
2966                 case SPECIFIER_INT64:
2967                 case SPECIFIER_SIGNED | SPECIFIER_INT64:
2968                         atomic_type = int64_type_kind;
2969                         break;
2970
2971                 case SPECIFIER_INT128:
2972                 case SPECIFIER_SIGNED | SPECIFIER_INT128:
2973                         atomic_type = int128_type_kind;
2974                         break;
2975
2976                 case SPECIFIER_FLOAT:
2977                         atomic_type = ATOMIC_TYPE_FLOAT;
2978                         break;
2979                 case SPECIFIER_DOUBLE:
2980                         atomic_type = ATOMIC_TYPE_DOUBLE;
2981                         break;
2982                 case SPECIFIER_LONG | SPECIFIER_DOUBLE:
2983                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
2984                         break;
2985                 case SPECIFIER_BOOL:
2986                         atomic_type = ATOMIC_TYPE_BOOL;
2987                         break;
2988                 case SPECIFIER_FLOAT | SPECIFIER_COMPLEX:
2989                 case SPECIFIER_FLOAT | SPECIFIER_IMAGINARY:
2990                         atomic_type = ATOMIC_TYPE_FLOAT;
2991                         break;
2992                 case SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
2993                 case SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
2994                         atomic_type = ATOMIC_TYPE_DOUBLE;
2995                         break;
2996                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
2997                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
2998                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
2999                         break;
3000                 default: {
3001                         /* invalid specifier combination, give an error message */
3002                         source_position_t const* const pos = &specifiers->source_position;
3003                         if (type_specifiers == 0) {
3004                                 if (!saw_error) {
3005                                         /* ISO/IEC 14882:1998(E) §C.1.5:4 */
3006                                         if (!(c_mode & _CXX) && !strict_mode) {
3007                                                 warningf(WARN_IMPLICIT_INT, pos, "no type specifiers in declaration, using 'int'");
3008                                                 atomic_type = ATOMIC_TYPE_INT;
3009                                                 break;
3010                                         } else {
3011                                                 errorf(pos, "no type specifiers given in declaration");
3012                                         }
3013                                 }
3014                         } else if ((type_specifiers & SPECIFIER_SIGNED) &&
3015                                   (type_specifiers & SPECIFIER_UNSIGNED)) {
3016                                 errorf(pos, "signed and unsigned specifiers given");
3017                         } else if (type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
3018                                 errorf(pos, "only integer types can be signed or unsigned");
3019                         } else {
3020                                 errorf(pos, "multiple datatypes in declaration");
3021                         }
3022                         specifiers->type = type_error_type;
3023                         return;
3024                 }
3025                 }
3026
3027                 if (type_specifiers & SPECIFIER_COMPLEX) {
3028                         type = allocate_type_zero(TYPE_COMPLEX);
3029                 } else if (type_specifiers & SPECIFIER_IMAGINARY) {
3030                         type = allocate_type_zero(TYPE_IMAGINARY);
3031                 } else {
3032                         type = allocate_type_zero(TYPE_ATOMIC);
3033                 }
3034                 type->atomic.akind = atomic_type;
3035                 newtype = true;
3036         } else if (type_specifiers != 0) {
3037                 errorf(&specifiers->source_position, "multiple datatypes in declaration");
3038         }
3039
3040         /* FIXME: check type qualifiers here */
3041         type->base.qualifiers = qualifiers;
3042
3043         if (newtype) {
3044                 type = identify_new_type(type);
3045         } else {
3046                 type = typehash_insert(type);
3047         }
3048
3049         if (specifiers->attributes != NULL)
3050                 type = handle_type_attributes(specifiers->attributes, type);
3051         specifiers->type = type;
3052 }
3053
3054 static type_qualifiers_t parse_type_qualifiers(void)
3055 {
3056         type_qualifiers_t qualifiers = TYPE_QUALIFIER_NONE;
3057
3058         while (true) {
3059                 switch (token.kind) {
3060                 /* type qualifiers */
3061                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
3062                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
3063                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
3064                 /* microsoft extended type modifiers */
3065                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
3066                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
3067                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
3068                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
3069                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
3070
3071                 default:
3072                         return qualifiers;
3073                 }
3074         }
3075 }
3076
3077 /**
3078  * Parses an K&R identifier list
3079  */
3080 static void parse_identifier_list(scope_t *scope)
3081 {
3082         assert(token.kind == T_IDENTIFIER);
3083         do {
3084                 entity_t *const entity = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, token.base.symbol, HERE);
3085                 /* a K&R parameter has no type, yet */
3086                 eat(T_IDENTIFIER);
3087
3088                 if (scope != NULL)
3089                         append_entity(scope, entity);
3090         } while (accept(',') && token.kind == T_IDENTIFIER);
3091 }
3092
3093 static entity_t *parse_parameter(void)
3094 {
3095         declaration_specifiers_t specifiers;
3096         parse_declaration_specifiers(&specifiers);
3097
3098         entity_t *entity = parse_declarator(&specifiers,
3099                         DECL_MAY_BE_ABSTRACT | DECL_IS_PARAMETER);
3100         anonymous_entity = NULL;
3101         return entity;
3102 }
3103
3104 static void semantic_parameter_incomplete(const entity_t *entity)
3105 {
3106         assert(entity->kind == ENTITY_PARAMETER);
3107
3108         /* §6.7.5.3:4  After adjustment, the parameters in a parameter type
3109          *             list in a function declarator that is part of a
3110          *             definition of that function shall not have
3111          *             incomplete type. */
3112         type_t *type = skip_typeref(entity->declaration.type);
3113         if (is_type_incomplete(type)) {
3114                 errorf(&entity->base.source_position, "'%N' has incomplete type", entity);
3115         }
3116 }
3117
3118 static bool has_parameters(void)
3119 {
3120         /* func(void) is not a parameter */
3121         if (look_ahead(1)->kind != ')')
3122                 return true;
3123         if (token.kind == T_IDENTIFIER) {
3124                 entity_t const *const entity = get_entity(token.base.symbol, NAMESPACE_NORMAL);
3125                 if (entity == NULL)
3126                         return true;
3127                 if (entity->kind != ENTITY_TYPEDEF)
3128                         return true;
3129                 type_t const *const type = skip_typeref(entity->typedefe.type);
3130                 if (!is_type_void(type))
3131                         return true;
3132                 if (c_mode & _CXX) {
3133                         /* ISO/IEC 14882:1998(E) §8.3.5:2  It must be literally (void).  A typedef
3134                          * is not allowed. */
3135                         errorf(HERE, "empty parameter list defined with a typedef of 'void' not allowed in C++");
3136                 } else if (type->base.qualifiers != TYPE_QUALIFIER_NONE) {
3137                         /* §6.7.5.3:10  Qualification is not allowed here. */
3138                         errorf(HERE, "'void' as parameter must not have type qualifiers");
3139                 }
3140         } else if (token.kind != T_void) {
3141                 return true;
3142         }
3143         next_token();
3144         return false;
3145 }
3146
3147 /**
3148  * Parses function type parameters (and optionally creates variable_t entities
3149  * for them in a scope)
3150  */
3151 static void parse_parameters(function_type_t *type, scope_t *scope)
3152 {
3153         add_anchor_token(')');
3154         eat('(');
3155
3156         if (token.kind == T_IDENTIFIER            &&
3157             !is_typedef_symbol(token.base.symbol) &&
3158             (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
3159                 type->kr_style_parameters = true;
3160                 parse_identifier_list(scope);
3161         } else if (token.kind == ')') {
3162                 /* ISO/IEC 14882:1998(E) §C.1.6:1 */
3163                 if (!(c_mode & _CXX))
3164                         type->unspecified_parameters = true;
3165         } else if (has_parameters()) {
3166                 function_parameter_t **anchor = &type->parameters;
3167                 add_anchor_token(',');
3168                 do {
3169                         switch (token.kind) {
3170                         case T_DOTDOTDOT:
3171                                 eat(T_DOTDOTDOT);
3172                                 type->variadic = true;
3173                                 goto parameters_finished;
3174
3175                         case T_IDENTIFIER:
3176                         DECLARATION_START
3177                         {
3178                                 entity_t *entity = parse_parameter();
3179                                 if (entity->kind == ENTITY_TYPEDEF) {
3180                                         errorf(&entity->base.source_position,
3181                                                         "typedef not allowed as function parameter");
3182                                         break;
3183                                 }
3184                                 assert(is_declaration(entity));
3185
3186                                 semantic_parameter_incomplete(entity);
3187
3188                                 function_parameter_t *const parameter =
3189                                         allocate_parameter(entity->declaration.type);
3190
3191                                 if (scope != NULL) {
3192                                         append_entity(scope, entity);
3193                                 }
3194
3195                                 *anchor = parameter;
3196                                 anchor  = &parameter->next;
3197                                 break;
3198                         }
3199
3200                         default:
3201                                 goto parameters_finished;
3202                         }
3203                 } while (accept(','));
3204 parameters_finished:
3205                 rem_anchor_token(',');
3206         }
3207
3208         rem_anchor_token(')');
3209         expect(')');
3210 }
3211
3212 typedef enum construct_type_kind_t {
3213         CONSTRUCT_POINTER = 1,
3214         CONSTRUCT_REFERENCE,
3215         CONSTRUCT_FUNCTION,
3216         CONSTRUCT_ARRAY
3217 } construct_type_kind_t;
3218
3219 typedef union construct_type_t construct_type_t;
3220
3221 typedef struct construct_type_base_t {
3222         construct_type_kind_t  kind;
3223         source_position_t      pos;
3224         construct_type_t      *next;
3225 } construct_type_base_t;
3226
3227 typedef struct parsed_pointer_t {
3228         construct_type_base_t  base;
3229         type_qualifiers_t      type_qualifiers;
3230         variable_t            *base_variable;  /**< MS __based extension. */
3231 } parsed_pointer_t;
3232
3233 typedef struct parsed_reference_t {
3234         construct_type_base_t base;
3235 } parsed_reference_t;
3236
3237 typedef struct construct_function_type_t {
3238         construct_type_base_t  base;
3239         type_t                *function_type;
3240 } construct_function_type_t;
3241
3242 typedef struct parsed_array_t {
3243         construct_type_base_t  base;
3244         type_qualifiers_t      type_qualifiers;
3245         bool                   is_static;
3246         bool                   is_variable;
3247         expression_t          *size;
3248 } parsed_array_t;
3249
3250 union construct_type_t {
3251         construct_type_kind_t     kind;
3252         construct_type_base_t     base;
3253         parsed_pointer_t          pointer;
3254         parsed_reference_t        reference;
3255         construct_function_type_t function;
3256         parsed_array_t            array;
3257 };
3258
3259 static construct_type_t *allocate_declarator_zero(construct_type_kind_t const kind, size_t const size)
3260 {
3261         construct_type_t *const cons = obstack_alloc(&temp_obst, size);
3262         memset(cons, 0, size);
3263         cons->kind     = kind;
3264         cons->base.pos = *HERE;
3265         return cons;
3266 }
3267
3268 /* §6.7.5.1 */
3269 static construct_type_t *parse_pointer_declarator(void)
3270 {
3271         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_POINTER, sizeof(parsed_pointer_t));
3272         eat('*');
3273         cons->pointer.type_qualifiers = parse_type_qualifiers();
3274         //cons->pointer.base_variable   = base_variable;
3275
3276         return cons;
3277 }
3278
3279 /* ISO/IEC 14882:1998(E) §8.3.2 */
3280 static construct_type_t *parse_reference_declarator(void)
3281 {
3282         if (!(c_mode & _CXX))
3283                 errorf(HERE, "references are only available for C++");
3284
3285         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_REFERENCE, sizeof(parsed_reference_t));
3286         eat('&');
3287
3288         return cons;
3289 }
3290
3291 /* §6.7.5.2 */
3292 static construct_type_t *parse_array_declarator(void)
3293 {
3294         construct_type_t *const cons  = allocate_declarator_zero(CONSTRUCT_ARRAY, sizeof(parsed_array_t));
3295         parsed_array_t   *const array = &cons->array;
3296
3297         eat('[');
3298         add_anchor_token(']');
3299
3300         bool is_static = accept(T_static);
3301
3302         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
3303
3304         if (!is_static)
3305                 is_static = accept(T_static);
3306
3307         array->type_qualifiers = type_qualifiers;
3308         array->is_static       = is_static;
3309
3310         expression_t *size = NULL;
3311         if (token.kind == '*' && look_ahead(1)->kind == ']') {
3312                 array->is_variable = true;
3313                 eat('*');
3314         } else if (token.kind != ']') {
3315                 size = parse_assignment_expression();
3316
3317                 /* §6.7.5.2:1  Array size must have integer type */
3318                 type_t *const orig_type = size->base.type;
3319                 type_t *const type      = skip_typeref(orig_type);
3320                 if (!is_type_integer(type) && is_type_valid(type)) {
3321                         errorf(&size->base.source_position,
3322                                "array size '%E' must have integer type but has type '%T'",
3323                                size, orig_type);
3324                 }
3325
3326                 array->size = size;
3327                 mark_vars_read(size, NULL);
3328         }
3329
3330         if (is_static && size == NULL)
3331                 errorf(&array->base.pos, "static array parameters require a size");
3332
3333         rem_anchor_token(']');
3334         expect(']');
3335         return cons;
3336 }
3337
3338 /* §6.7.5.3 */
3339 static construct_type_t *parse_function_declarator(scope_t *scope)
3340 {
3341         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_FUNCTION, sizeof(construct_function_type_t));
3342
3343         type_t          *type  = allocate_type_zero(TYPE_FUNCTION);
3344         function_type_t *ftype = &type->function;
3345
3346         ftype->linkage            = current_linkage;
3347         ftype->calling_convention = CC_DEFAULT;
3348
3349         parse_parameters(ftype, scope);
3350
3351         cons->function.function_type = type;
3352
3353         return cons;
3354 }
3355
3356 typedef struct parse_declarator_env_t {
3357         bool               may_be_abstract : 1;
3358         bool               must_be_abstract : 1;
3359         decl_modifiers_t   modifiers;
3360         symbol_t          *symbol;
3361         source_position_t  source_position;
3362         scope_t            parameters;
3363         attribute_t       *attributes;
3364 } parse_declarator_env_t;
3365
3366 /* §6.7.5 */
3367 static construct_type_t *parse_inner_declarator(parse_declarator_env_t *env)
3368 {
3369         /* construct a single linked list of construct_type_t's which describe
3370          * how to construct the final declarator type */
3371         construct_type_t  *first      = NULL;
3372         construct_type_t **anchor     = &first;
3373
3374         env->attributes = parse_attributes(env->attributes);
3375
3376         for (;;) {
3377                 construct_type_t *type;
3378                 //variable_t       *based = NULL; /* MS __based extension */
3379                 switch (token.kind) {
3380                         case '&':
3381                                 type = parse_reference_declarator();
3382                                 break;
3383
3384                         case T__based: {
3385                                 panic("based not supported anymore");
3386                                 /* FALLTHROUGH */
3387                         }
3388
3389                         case '*':
3390                                 type = parse_pointer_declarator();
3391                                 break;
3392
3393                         default:
3394                                 goto ptr_operator_end;
3395                 }
3396
3397                 *anchor = type;
3398                 anchor  = &type->base.next;
3399
3400                 /* TODO: find out if this is correct */
3401                 env->attributes = parse_attributes(env->attributes);
3402         }
3403
3404 ptr_operator_end: ;
3405         construct_type_t *inner_types = NULL;
3406
3407         switch (token.kind) {
3408         case T_IDENTIFIER:
3409                 if (env->must_be_abstract) {
3410                         errorf(HERE, "no identifier expected in typename");
3411                 } else {
3412                         env->symbol          = token.base.symbol;
3413                         env->source_position = *HERE;
3414                 }
3415                 eat(T_IDENTIFIER);
3416                 break;
3417
3418         case '(': {
3419                 /* Parenthesized declarator or function declarator? */
3420                 token_t const *const la1 = look_ahead(1);
3421                 switch (la1->kind) {
3422                         case T_IDENTIFIER:
3423                                 if (is_typedef_symbol(la1->base.symbol)) {
3424                         case ')':
3425                                         /* §6.7.6:2 footnote 126:  Empty parentheses in a type name are
3426                                          * interpreted as ``function with no parameter specification'', rather
3427                                          * than redundant parentheses around the omitted identifier. */
3428                         default:
3429                                         /* Function declarator. */
3430                                         if (!env->may_be_abstract) {
3431                                                 errorf(HERE, "function declarator must have a name");
3432                                         }
3433                                 } else {
3434                         case '&':
3435                         case '(':
3436                         case '*':
3437                         case '[':
3438                         case T___attribute__: /* FIXME __attribute__ might also introduce a parameter of a function declarator. */
3439                                         /* Paranthesized declarator. */
3440                                         eat('(');
3441                                         add_anchor_token(')');
3442                                         inner_types = parse_inner_declarator(env);
3443                                         if (inner_types != NULL) {
3444                                                 /* All later declarators only modify the return type */
3445                                                 env->must_be_abstract = true;
3446                                         }
3447                                         rem_anchor_token(')');
3448                                         expect(')');
3449                                 }
3450                                 break;
3451                 }
3452                 break;
3453         }
3454
3455         default:
3456                 if (env->may_be_abstract)
3457                         break;
3458                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', NULL);
3459                 eat_until_anchor();
3460                 return NULL;
3461         }
3462
3463         construct_type_t **const p = anchor;
3464
3465         for (;;) {
3466                 construct_type_t *type;
3467                 switch (token.kind) {
3468                 case '(': {
3469                         scope_t *scope = NULL;
3470                         if (!env->must_be_abstract) {
3471                                 scope = &env->parameters;
3472                         }
3473
3474                         type = parse_function_declarator(scope);
3475                         break;
3476                 }
3477                 case '[':
3478                         type = parse_array_declarator();
3479                         break;
3480                 default:
3481                         goto declarator_finished;
3482                 }
3483
3484                 /* insert in the middle of the list (at p) */
3485                 type->base.next = *p;
3486                 *p              = type;
3487                 if (anchor == p)
3488                         anchor = &type->base.next;
3489         }
3490
3491 declarator_finished:
3492         /* append inner_types at the end of the list, we don't to set anchor anymore
3493          * as it's not needed anymore */
3494         *anchor = inner_types;
3495
3496         return first;
3497 }
3498
3499 static type_t *construct_declarator_type(construct_type_t *construct_list,
3500                                          type_t *type)
3501 {
3502         construct_type_t *iter = construct_list;
3503         for (; iter != NULL; iter = iter->base.next) {
3504                 source_position_t const* const pos = &iter->base.pos;
3505                 switch (iter->kind) {
3506                 case CONSTRUCT_FUNCTION: {
3507                         construct_function_type_t *function      = &iter->function;
3508                         type_t                    *function_type = function->function_type;
3509
3510                         function_type->function.return_type = type;
3511
3512                         type_t *skipped_return_type = skip_typeref(type);
3513                         /* §6.7.5.3:1 */
3514                         if (is_type_function(skipped_return_type)) {
3515                                 errorf(pos, "function returning function is not allowed");
3516                         } else if (is_type_array(skipped_return_type)) {
3517                                 errorf(pos, "function returning array is not allowed");
3518                         } else {
3519                                 if (skipped_return_type->base.qualifiers != 0) {
3520                                         warningf(WARN_IGNORED_QUALIFIERS, pos, "type qualifiers in return type of function type are meaningless");
3521                                 }
3522                         }
3523
3524                         /* The function type was constructed earlier.  Freeing it here will
3525                          * destroy other types. */
3526                         type = typehash_insert(function_type);
3527                         continue;
3528                 }
3529
3530                 case CONSTRUCT_POINTER: {
3531                         if (is_type_reference(skip_typeref(type)))
3532                                 errorf(pos, "cannot declare a pointer to reference");
3533
3534                         parsed_pointer_t *pointer = &iter->pointer;
3535                         type = make_based_pointer_type(type, pointer->type_qualifiers, pointer->base_variable);
3536                         continue;
3537                 }
3538
3539                 case CONSTRUCT_REFERENCE:
3540                         if (is_type_reference(skip_typeref(type)))
3541                                 errorf(pos, "cannot declare a reference to reference");
3542
3543                         type = make_reference_type(type);
3544                         continue;
3545
3546                 case CONSTRUCT_ARRAY: {
3547                         if (is_type_reference(skip_typeref(type)))
3548                                 errorf(pos, "cannot declare an array of references");
3549
3550                         parsed_array_t *array      = &iter->array;
3551                         type_t         *array_type = allocate_type_zero(TYPE_ARRAY);
3552
3553                         expression_t *size_expression = array->size;
3554                         if (size_expression != NULL) {
3555                                 size_expression
3556                                         = create_implicit_cast(size_expression, type_size_t);
3557                         }
3558
3559                         array_type->base.qualifiers       = array->type_qualifiers;
3560                         array_type->array.element_type    = type;
3561                         array_type->array.is_static       = array->is_static;
3562                         array_type->array.is_variable     = array->is_variable;
3563                         array_type->array.size_expression = size_expression;
3564
3565                         if (size_expression != NULL) {
3566                                 switch (is_constant_expression(size_expression)) {
3567                                 case EXPR_CLASS_CONSTANT: {
3568                                         long const size = fold_constant_to_int(size_expression);
3569                                         array_type->array.size          = size;
3570                                         array_type->array.size_constant = true;
3571                                         /* §6.7.5.2:1  If the expression is a constant expression,
3572                                          * it shall have a value greater than zero. */
3573                                         if (size < 0) {
3574                                                 errorf(&size_expression->base.source_position,
3575                                                            "size of array must be greater than zero");
3576                                         } else if (size == 0 && !GNU_MODE) {
3577                                                 errorf(&size_expression->base.source_position,
3578                                                            "size of array must be greater than zero (zero length arrays are a GCC extension)");
3579                                         }
3580                                         break;
3581                                 }
3582
3583                                 case EXPR_CLASS_VARIABLE:
3584                                         array_type->array.is_vla = true;
3585                                         break;
3586
3587                                 case EXPR_CLASS_ERROR:
3588                                         break;
3589                                 }
3590                         }
3591
3592                         type_t *skipped_type = skip_typeref(type);
3593                         /* §6.7.5.2:1 */
3594                         if (is_type_incomplete(skipped_type)) {
3595                                 errorf(pos, "array of incomplete type '%T' is not allowed", type);
3596                         } else if (is_type_function(skipped_type)) {
3597                                 errorf(pos, "array of functions is not allowed");
3598                         }
3599                         type = identify_new_type(array_type);
3600                         continue;
3601                 }
3602                 }
3603                 internal_errorf(pos, "invalid type construction found");
3604         }
3605
3606         return type;
3607 }
3608
3609 static type_t *automatic_type_conversion(type_t *orig_type);
3610
3611 static type_t *semantic_parameter(const source_position_t *pos,
3612                                   type_t *type,
3613                                   const declaration_specifiers_t *specifiers,
3614                                   entity_t const *const param)
3615 {
3616         /* §6.7.5.3:7  A declaration of a parameter as ``array of type''
3617          *             shall be adjusted to ``qualified pointer to type'',
3618          *             [...]
3619          * §6.7.5.3:8  A declaration of a parameter as ``function returning
3620          *             type'' shall be adjusted to ``pointer to function
3621          *             returning type'', as in 6.3.2.1. */
3622         type = automatic_type_conversion(type);
3623
3624         if (specifiers->is_inline && is_type_valid(type)) {
3625                 errorf(pos, "'%N' declared 'inline'", param);
3626         }
3627
3628         /* §6.9.1:6  The declarations in the declaration list shall contain
3629          *           no storage-class specifier other than register and no
3630          *           initializations. */
3631         if (specifiers->thread_local || (
3632                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3633                         specifiers->storage_class != STORAGE_CLASS_REGISTER)
3634            ) {
3635                 errorf(pos, "invalid storage class for '%N'", param);
3636         }
3637
3638         /* delay test for incomplete type, because we might have (void)
3639          * which is legal but incomplete... */
3640
3641         return type;
3642 }
3643
3644 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
3645                                   declarator_flags_t flags)
3646 {
3647         parse_declarator_env_t env;
3648         memset(&env, 0, sizeof(env));
3649         env.may_be_abstract = (flags & DECL_MAY_BE_ABSTRACT) != 0;
3650
3651         construct_type_t *construct_type = parse_inner_declarator(&env);
3652         type_t           *orig_type      =
3653                 construct_declarator_type(construct_type, specifiers->type);
3654         type_t           *type           = skip_typeref(orig_type);
3655
3656         if (construct_type != NULL) {
3657                 obstack_free(&temp_obst, construct_type);
3658         }
3659
3660         attribute_t *attributes = parse_attributes(env.attributes);
3661         /* append (shared) specifier attribute behind attributes of this
3662          * declarator */
3663         attribute_t **anchor = &attributes;
3664         while (*anchor != NULL)
3665                 anchor = &(*anchor)->next;
3666         *anchor = specifiers->attributes;
3667
3668         entity_t *entity;
3669         if (specifiers->storage_class == STORAGE_CLASS_TYPEDEF) {
3670                 entity = allocate_entity_zero(ENTITY_TYPEDEF, NAMESPACE_NORMAL, env.symbol, &env.source_position);
3671                 entity->typedefe.type = orig_type;
3672
3673                 if (anonymous_entity != NULL) {
3674                         if (is_type_compound(type)) {
3675                                 assert(anonymous_entity->compound.alias == NULL);
3676                                 assert(anonymous_entity->kind == ENTITY_STRUCT ||
3677                                        anonymous_entity->kind == ENTITY_UNION);
3678                                 anonymous_entity->compound.alias = entity;
3679                                 anonymous_entity = NULL;
3680                         } else if (is_type_enum(type)) {
3681                                 assert(anonymous_entity->enume.alias == NULL);
3682                                 assert(anonymous_entity->kind == ENTITY_ENUM);
3683                                 anonymous_entity->enume.alias = entity;
3684                                 anonymous_entity = NULL;
3685                         }
3686                 }
3687         } else {
3688                 /* create a declaration type entity */
3689                 source_position_t const *const pos = env.symbol ? &env.source_position : &specifiers->source_position;
3690                 if (flags & DECL_CREATE_COMPOUND_MEMBER) {
3691                         entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, env.symbol, pos);
3692
3693                         if (env.symbol != NULL) {
3694                                 if (specifiers->is_inline && is_type_valid(type)) {
3695                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3696                                 }
3697
3698                                 if (specifiers->thread_local ||
3699                                                 specifiers->storage_class != STORAGE_CLASS_NONE) {
3700                                         errorf(&env.source_position, "'%N' must have no storage class", entity);
3701                                 }
3702                         }
3703                 } else if (flags & DECL_IS_PARAMETER) {
3704                         entity    = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, env.symbol, pos);
3705                         orig_type = semantic_parameter(&env.source_position, orig_type, specifiers, entity);
3706                 } else if (is_type_function(type)) {
3707                         entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, env.symbol, pos);
3708                         entity->function.is_inline      = specifiers->is_inline;
3709                         entity->function.elf_visibility = default_visibility;
3710                         entity->function.parameters     = env.parameters;
3711
3712                         if (env.symbol != NULL) {
3713                                 /* this needs fixes for C++ */
3714                                 bool in_function_scope = current_function != NULL;
3715
3716                                 if (specifiers->thread_local || (
3717                                                         specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3718                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3719                                                         (in_function_scope || specifiers->storage_class != STORAGE_CLASS_STATIC)
3720                                                 )) {
3721                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3722                                 }
3723                         }
3724                 } else {
3725                         entity = allocate_entity_zero(ENTITY_VARIABLE, NAMESPACE_NORMAL, env.symbol, pos);
3726                         entity->variable.elf_visibility = default_visibility;
3727                         entity->variable.thread_local   = specifiers->thread_local;
3728
3729                         if (env.symbol != NULL) {
3730                                 if (specifiers->is_inline && is_type_valid(type)) {
3731                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3732                                 }
3733
3734                                 bool invalid_storage_class = false;
3735                                 if (current_scope == file_scope) {
3736                                         if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3737                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3738                                                         specifiers->storage_class != STORAGE_CLASS_STATIC) {
3739                                                 invalid_storage_class = true;
3740                                         }
3741                                 } else {
3742                                         if (specifiers->thread_local &&
3743                                                         specifiers->storage_class == STORAGE_CLASS_NONE) {
3744                                                 invalid_storage_class = true;
3745                                         }
3746                                 }
3747                                 if (invalid_storage_class) {
3748                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3749                                 }
3750                         }
3751                 }
3752
3753                 entity->declaration.type       = orig_type;
3754                 entity->declaration.alignment  = get_type_alignment(orig_type);
3755                 entity->declaration.modifiers  = env.modifiers;
3756                 entity->declaration.attributes = attributes;
3757
3758                 storage_class_t storage_class = specifiers->storage_class;
3759                 entity->declaration.declared_storage_class = storage_class;
3760
3761                 if (storage_class == STORAGE_CLASS_NONE && current_function != NULL)
3762                         storage_class = STORAGE_CLASS_AUTO;
3763                 entity->declaration.storage_class = storage_class;
3764         }
3765
3766         if (attributes != NULL) {
3767                 handle_entity_attributes(attributes, entity);
3768         }
3769
3770         if (entity->kind == ENTITY_FUNCTION && !freestanding) {
3771                 adapt_special_functions(&entity->function);
3772         }
3773
3774         return entity;
3775 }
3776
3777 static type_t *parse_abstract_declarator(type_t *base_type)
3778 {
3779         parse_declarator_env_t env;
3780         memset(&env, 0, sizeof(env));
3781         env.may_be_abstract = true;
3782         env.must_be_abstract = true;
3783
3784         construct_type_t *construct_type = parse_inner_declarator(&env);
3785
3786         type_t *result = construct_declarator_type(construct_type, base_type);
3787         if (construct_type != NULL) {
3788                 obstack_free(&temp_obst, construct_type);
3789         }
3790         result = handle_type_attributes(env.attributes, result);
3791
3792         return result;
3793 }
3794
3795 /**
3796  * Check if the declaration of main is suspicious.  main should be a
3797  * function with external linkage, returning int, taking either zero
3798  * arguments, two, or three arguments of appropriate types, ie.
3799  *
3800  * int main([ int argc, char **argv [, char **env ] ]).
3801  *
3802  * @param decl    the declaration to check
3803  * @param type    the function type of the declaration
3804  */
3805 static void check_main(const entity_t *entity)
3806 {
3807         const source_position_t *pos = &entity->base.source_position;
3808         if (entity->kind != ENTITY_FUNCTION) {
3809                 warningf(WARN_MAIN, pos, "'main' is not a function");
3810                 return;
3811         }
3812
3813         if (entity->declaration.storage_class == STORAGE_CLASS_STATIC) {
3814                 warningf(WARN_MAIN, pos, "'main' is normally a non-static function");
3815         }
3816
3817         type_t *type = skip_typeref(entity->declaration.type);
3818         assert(is_type_function(type));
3819
3820         function_type_t const *const func_type = &type->function;
3821         type_t                *const ret_type  = func_type->return_type;
3822         if (!types_compatible(skip_typeref(ret_type), type_int)) {
3823                 warningf(WARN_MAIN, pos, "return type of 'main' should be 'int', but is '%T'", ret_type);
3824         }
3825         const function_parameter_t *parm = func_type->parameters;
3826         if (parm != NULL) {
3827                 type_t *const first_type        = skip_typeref(parm->type);
3828                 type_t *const first_type_unqual = get_unqualified_type(first_type);
3829                 if (!types_compatible(first_type_unqual, type_int)) {
3830                         warningf(WARN_MAIN, pos, "first argument of 'main' should be 'int', but is '%T'", parm->type);
3831                 }
3832                 parm = parm->next;
3833                 if (parm != NULL) {
3834                         type_t *const second_type = skip_typeref(parm->type);
3835                         type_t *const second_type_unqual
3836                                 = get_unqualified_type(second_type);
3837                         if (!types_compatible(second_type_unqual, type_char_ptr_ptr)) {
3838                                 warningf(WARN_MAIN, pos, "second argument of 'main' should be 'char**', but is '%T'", parm->type);
3839                         }
3840                         parm = parm->next;
3841                         if (parm != NULL) {
3842                                 type_t *const third_type = skip_typeref(parm->type);
3843                                 type_t *const third_type_unqual
3844                                         = get_unqualified_type(third_type);
3845                                 if (!types_compatible(third_type_unqual, type_char_ptr_ptr)) {
3846                                         warningf(WARN_MAIN, pos, "third argument of 'main' should be 'char**', but is '%T'", parm->type);
3847                                 }
3848                                 parm = parm->next;
3849                                 if (parm != NULL)
3850                                         goto warn_arg_count;
3851                         }
3852                 } else {
3853 warn_arg_count:
3854                         warningf(WARN_MAIN, pos, "'main' takes only zero, two or three arguments");
3855                 }
3856         }
3857 }
3858
3859 static void error_redefined_as_different_kind(const source_position_t *pos,
3860                 const entity_t *old, entity_kind_t new_kind)
3861 {
3862         char              const *const what = get_entity_kind_name(new_kind);
3863         source_position_t const *const ppos = &old->base.source_position;
3864         errorf(pos, "redeclaration of '%N' as %s (declared %P)", old, what, ppos);
3865 }
3866
3867 static bool is_entity_valid(entity_t *const ent)
3868 {
3869         if (is_declaration(ent)) {
3870                 return is_type_valid(skip_typeref(ent->declaration.type));
3871         } else if (ent->kind == ENTITY_TYPEDEF) {
3872                 return is_type_valid(skip_typeref(ent->typedefe.type));
3873         }
3874         return true;
3875 }
3876
3877 static bool contains_attribute(const attribute_t *list, const attribute_t *attr)
3878 {
3879         for (const attribute_t *tattr = list; tattr != NULL; tattr = tattr->next) {
3880                 if (attributes_equal(tattr, attr))
3881                         return true;
3882         }
3883         return false;
3884 }
3885
3886 /**
3887  * test wether new_list contains any attributes not included in old_list
3888  */
3889 static bool has_new_attributes(const attribute_t *old_list,
3890                                const attribute_t *new_list)
3891 {
3892         for (const attribute_t *attr = new_list; attr != NULL; attr = attr->next) {
3893                 if (!contains_attribute(old_list, attr))
3894                         return true;
3895         }
3896         return false;
3897 }
3898
3899 /**
3900  * Merge in attributes from an attribute list (probably from a previous
3901  * declaration with the same name). Warning: destroys the old structure
3902  * of the attribute list - don't reuse attributes after this call.
3903  */
3904 static void merge_in_attributes(declaration_t *decl, attribute_t *attributes)
3905 {
3906         attribute_t *next;
3907         for (attribute_t *attr = attributes; attr != NULL; attr = next) {
3908                 next = attr->next;
3909                 if (contains_attribute(decl->attributes, attr))
3910                         continue;
3911
3912                 /* move attribute to new declarations attributes list */
3913                 attr->next       = decl->attributes;
3914                 decl->attributes = attr;
3915         }
3916 }
3917
3918 static bool is_main(entity_t*);
3919
3920 /**
3921  * record entities for the NAMESPACE_NORMAL, and produce error messages/warnings
3922  * for various problems that occur for multiple definitions
3923  */
3924 entity_t *record_entity(entity_t *entity, const bool is_definition)
3925 {
3926         const symbol_t *const    symbol  = entity->base.symbol;
3927         const namespace_tag_t    namespc = (namespace_tag_t)entity->base.namespc;
3928         const source_position_t *pos     = &entity->base.source_position;
3929
3930         /* can happen in error cases */
3931         if (symbol == NULL)
3932                 return entity;
3933
3934         assert(!entity->base.parent_scope);
3935         assert(current_scope);
3936         entity->base.parent_scope = current_scope;
3937
3938         entity_t *const previous_entity = get_entity(symbol, namespc);
3939         /* pushing the same entity twice will break the stack structure */
3940         assert(previous_entity != entity);
3941
3942         if (entity->kind == ENTITY_FUNCTION) {
3943                 type_t *const orig_type = entity->declaration.type;
3944                 type_t *const type      = skip_typeref(orig_type);
3945
3946                 assert(is_type_function(type));
3947                 if (type->function.unspecified_parameters &&
3948                     previous_entity == NULL               &&
3949                     !entity->declaration.implicit) {
3950                         warningf(WARN_STRICT_PROTOTYPES, pos, "function declaration '%#N' is not a prototype", entity);
3951                 }
3952
3953                 if (is_main(entity)) {
3954                         check_main(entity);
3955                 }
3956         }
3957
3958         if (is_declaration(entity)                                    &&
3959             entity->declaration.storage_class == STORAGE_CLASS_EXTERN &&
3960             current_scope != file_scope                               &&
3961             !entity->declaration.implicit) {
3962                 warningf(WARN_NESTED_EXTERNS, pos, "nested extern declaration of '%#N'", entity);
3963         }
3964
3965         if (previous_entity != NULL) {
3966                 source_position_t const *const ppos = &previous_entity->base.source_position;
3967
3968                 if (previous_entity->base.parent_scope == &current_function->parameters &&
3969                                 previous_entity->base.parent_scope->depth + 1 == current_scope->depth) {
3970                         assert(previous_entity->kind == ENTITY_PARAMETER);
3971                         errorf(pos, "declaration of '%N' redeclares the '%N' (declared %P)", entity, previous_entity, ppos);
3972                         goto finish;
3973                 }
3974
3975                 if (previous_entity->base.parent_scope == current_scope) {
3976                         if (previous_entity->kind != entity->kind) {
3977                                 if (is_entity_valid(previous_entity) && is_entity_valid(entity)) {
3978                                         error_redefined_as_different_kind(pos, previous_entity,
3979                                                         entity->kind);
3980                                 }
3981                                 goto finish;
3982                         }
3983                         if (previous_entity->kind == ENTITY_ENUM_VALUE) {
3984                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
3985                                 goto finish;
3986                         }
3987                         if (previous_entity->kind == ENTITY_TYPEDEF) {
3988                                 type_t *const type      = skip_typeref(entity->typedefe.type);
3989                                 type_t *const prev_type
3990                                         = skip_typeref(previous_entity->typedefe.type);
3991                                 if (c_mode & _CXX) {
3992                                         /* C++ allows double typedef if they are identical
3993                                          * (after skipping typedefs) */
3994                                         if (type == prev_type)
3995                                                 goto finish;
3996                                 } else {
3997                                         /* GCC extension: redef in system headers is allowed */
3998                                         if ((pos->is_system_header || ppos->is_system_header) &&
3999                                             types_compatible(type, prev_type))
4000                                                 goto finish;
4001                                 }
4002                                 errorf(pos, "redefinition of '%N' (declared %P)",
4003                                        entity, ppos);
4004                                 goto finish;
4005                         }
4006
4007                         /* at this point we should have only VARIABLES or FUNCTIONS */
4008                         assert(is_declaration(previous_entity) && is_declaration(entity));
4009
4010                         declaration_t *const prev_decl = &previous_entity->declaration;
4011                         declaration_t *const decl      = &entity->declaration;
4012
4013                         /* can happen for K&R style declarations */
4014                         if (prev_decl->type       == NULL             &&
4015                                         previous_entity->kind == ENTITY_PARAMETER &&
4016                                         entity->kind          == ENTITY_PARAMETER) {
4017                                 prev_decl->type                   = decl->type;
4018                                 prev_decl->storage_class          = decl->storage_class;
4019                                 prev_decl->declared_storage_class = decl->declared_storage_class;
4020                                 prev_decl->modifiers              = decl->modifiers;
4021                                 return previous_entity;
4022                         }
4023
4024                         type_t *const type      = skip_typeref(decl->type);
4025                         type_t *const prev_type = skip_typeref(prev_decl->type);
4026
4027                         if (!types_compatible(type, prev_type)) {
4028                                 errorf(pos, "declaration '%#N' is incompatible with '%#N' (declared %P)", entity, previous_entity, ppos);
4029                         } else {
4030                                 unsigned old_storage_class = prev_decl->storage_class;
4031
4032                                 if (is_definition                     &&
4033                                                 !prev_decl->used                  &&
4034                                                 !(prev_decl->modifiers & DM_USED) &&
4035                                                 prev_decl->storage_class == STORAGE_CLASS_STATIC) {
4036                                         warningf(WARN_REDUNDANT_DECLS, ppos, "unnecessary static forward declaration for '%#N'", previous_entity);
4037                                 }
4038
4039                                 storage_class_t new_storage_class = decl->storage_class;
4040
4041                                 /* pretend no storage class means extern for function
4042                                  * declarations (except if the previous declaration is neither
4043                                  * none nor extern) */
4044                                 if (entity->kind == ENTITY_FUNCTION) {
4045                                         /* the previous declaration could have unspecified parameters or
4046                                          * be a typedef, so use the new type */
4047                                         if (prev_type->function.unspecified_parameters || is_definition)
4048                                                 prev_decl->type = type;
4049
4050                                         switch (old_storage_class) {
4051                                                 case STORAGE_CLASS_NONE:
4052                                                         old_storage_class = STORAGE_CLASS_EXTERN;
4053                                                         /* FALLTHROUGH */
4054
4055                                                 case STORAGE_CLASS_EXTERN:
4056                                                         if (is_definition) {
4057                                                                 if (prev_type->function.unspecified_parameters && !is_main(entity)) {
4058                                                                         warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4059                                                                 }
4060                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
4061                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
4062                                                         }
4063                                                         break;
4064
4065                                                 default:
4066                                                         break;
4067                                         }
4068                                 } else if (is_type_incomplete(prev_type)) {
4069                                         prev_decl->type = type;
4070                                 }
4071
4072                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
4073                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
4074
4075 warn_redundant_declaration: ;
4076                                         bool has_new_attrs
4077                                                 = has_new_attributes(prev_decl->attributes,
4078                                                                      decl->attributes);
4079                                         if (has_new_attrs) {
4080                                                 merge_in_attributes(decl, prev_decl->attributes);
4081                                         } else if (!is_definition        &&
4082                                                         is_type_valid(prev_type) &&
4083                                                         !pos->is_system_header) {
4084                                                 warningf(WARN_REDUNDANT_DECLS, pos, "redundant declaration for '%N' (declared %P)", entity, ppos);
4085                                         }
4086                                 } else if (current_function == NULL) {
4087                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
4088                                                         new_storage_class == STORAGE_CLASS_STATIC) {
4089                                                 errorf(pos, "static declaration of '%N' follows non-static declaration (declared %P)", entity, ppos);
4090                                         } else if (old_storage_class == STORAGE_CLASS_EXTERN) {
4091                                                 prev_decl->storage_class          = STORAGE_CLASS_NONE;
4092                                                 prev_decl->declared_storage_class = STORAGE_CLASS_NONE;
4093                                         } else {
4094                                                 /* ISO/IEC 14882:1998(E) §C.1.2:1 */
4095                                                 if (c_mode & _CXX)
4096                                                         goto error_redeclaration;
4097                                                 goto warn_redundant_declaration;
4098                                         }
4099                                 } else if (is_type_valid(prev_type)) {
4100                                         if (old_storage_class == new_storage_class) {
4101 error_redeclaration:
4102                                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4103                                         } else {
4104                                                 errorf(pos, "redeclaration of '%N' with different linkage (declared %P)", entity, ppos);
4105                                         }
4106                                 }
4107                         }
4108
4109                         prev_decl->modifiers |= decl->modifiers;
4110                         if (entity->kind == ENTITY_FUNCTION) {
4111                                 previous_entity->function.is_inline |= entity->function.is_inline;
4112                         }
4113                         return previous_entity;
4114                 }
4115
4116                 warning_t why;
4117                 if (is_warn_on(why = WARN_SHADOW) ||
4118                     (is_warn_on(why = WARN_SHADOW_LOCAL) && previous_entity->base.parent_scope != file_scope)) {
4119                         char const *const what = get_entity_kind_name(previous_entity->kind);
4120                         warningf(why, pos, "'%N' shadows %s (declared %P)", entity, what, ppos);
4121                 }
4122         }
4123
4124         if (entity->kind == ENTITY_FUNCTION) {
4125                 if (is_definition &&
4126                                 entity->declaration.storage_class != STORAGE_CLASS_STATIC &&
4127                                 !is_main(entity)) {
4128                         if (is_warn_on(WARN_MISSING_PROTOTYPES)) {
4129                                 warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4130                         } else {
4131                                 goto warn_missing_declaration;
4132                         }
4133                 }
4134         } else if (entity->kind == ENTITY_VARIABLE) {
4135                 if (current_scope                     == file_scope &&
4136                                 entity->declaration.storage_class == STORAGE_CLASS_NONE &&
4137                                 !entity->declaration.implicit) {
4138 warn_missing_declaration:
4139                         warningf(WARN_MISSING_DECLARATIONS, pos, "no previous declaration for '%#N'", entity);
4140                 }
4141         }
4142
4143 finish:
4144         environment_push(entity);
4145         append_entity(current_scope, entity);
4146
4147         return entity;
4148 }
4149
4150 static void parser_error_multiple_definition(entity_t *entity,
4151                 const source_position_t *source_position)
4152 {
4153         errorf(source_position, "redefinition of '%N' (declared %P)", entity, &entity->base.source_position);
4154 }
4155
4156 static bool is_declaration_specifier(const token_t *token)
4157 {
4158         switch (token->kind) {
4159                 DECLARATION_START
4160                         return true;
4161                 case T_IDENTIFIER:
4162                         return is_typedef_symbol(token->base.symbol);
4163
4164                 default:
4165                         return false;
4166         }
4167 }
4168
4169 static void parse_init_declarator_rest(entity_t *entity)
4170 {
4171         type_t *orig_type = type_error_type;
4172
4173         if (entity->base.kind == ENTITY_TYPEDEF) {
4174                 source_position_t const *const pos = &entity->base.source_position;
4175                 errorf(pos, "'%N' is initialized (use __typeof__ instead)", entity);
4176         } else {
4177                 assert(is_declaration(entity));
4178                 orig_type = entity->declaration.type;
4179         }
4180
4181         type_t *type = skip_typeref(orig_type);
4182
4183         if (entity->kind == ENTITY_VARIABLE
4184                         && entity->variable.initializer != NULL) {
4185                 parser_error_multiple_definition(entity, HERE);
4186         }
4187         eat('=');
4188
4189         declaration_t *const declaration = &entity->declaration;
4190         bool must_be_constant = false;
4191         if (declaration->storage_class == STORAGE_CLASS_STATIC ||
4192             entity->base.parent_scope  == file_scope) {
4193                 must_be_constant = true;
4194         }
4195
4196         if (is_type_function(type)) {
4197                 source_position_t const *const pos = &entity->base.source_position;
4198                 errorf(pos, "'%N' is initialized like a variable", entity);
4199                 orig_type = type_error_type;
4200         }
4201
4202         parse_initializer_env_t env;
4203         env.type             = orig_type;
4204         env.must_be_constant = must_be_constant;
4205         env.entity           = entity;
4206
4207         initializer_t *initializer = parse_initializer(&env);
4208
4209         if (entity->kind == ENTITY_VARIABLE) {
4210                 /* §6.7.5:22  array initializers for arrays with unknown size
4211                  * determine the array type size */
4212                 declaration->type            = env.type;
4213                 entity->variable.initializer = initializer;
4214         }
4215 }
4216
4217 /* parse rest of a declaration without any declarator */
4218 static void parse_anonymous_declaration_rest(
4219                 const declaration_specifiers_t *specifiers)
4220 {
4221         eat(';');
4222         anonymous_entity = NULL;
4223
4224         source_position_t const *const pos = &specifiers->source_position;
4225         if (specifiers->storage_class != STORAGE_CLASS_NONE ||
4226                         specifiers->thread_local) {
4227                 warningf(WARN_OTHER, pos, "useless storage class in empty declaration");
4228         }
4229
4230         type_t *type = specifiers->type;
4231         switch (type->kind) {
4232                 case TYPE_COMPOUND_STRUCT:
4233                 case TYPE_COMPOUND_UNION: {
4234                         if (type->compound.compound->base.symbol == NULL) {
4235                                 warningf(WARN_OTHER, pos, "unnamed struct/union that defines no instances");
4236                         }
4237                         break;
4238                 }
4239
4240                 case TYPE_ENUM:
4241                         break;
4242
4243                 default:
4244                         warningf(WARN_OTHER, pos, "empty declaration");
4245                         break;
4246         }
4247 }
4248
4249 static void check_variable_type_complete(entity_t *ent)
4250 {
4251         if (ent->kind != ENTITY_VARIABLE)
4252                 return;
4253
4254         /* §6.7:7  If an identifier for an object is declared with no linkage, the
4255          *         type for the object shall be complete [...] */
4256         declaration_t *decl = &ent->declaration;
4257         if (decl->storage_class == STORAGE_CLASS_EXTERN ||
4258                         decl->storage_class == STORAGE_CLASS_STATIC)
4259                 return;
4260
4261         type_t *const type = skip_typeref(decl->type);
4262         if (!is_type_incomplete(type))
4263                 return;
4264
4265         /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
4266          * are given length one. */
4267         if (is_type_array(type) && ent->base.parent_scope == file_scope) {
4268                 ARR_APP1(declaration_t*, incomplete_arrays, decl);
4269                 return;
4270         }
4271
4272         errorf(&ent->base.source_position, "variable '%#N' has incomplete type", ent);
4273 }
4274
4275
4276 static void parse_declaration_rest(entity_t *ndeclaration,
4277                 const declaration_specifiers_t *specifiers,
4278                 parsed_declaration_func         finished_declaration,
4279                 declarator_flags_t              flags)
4280 {
4281         add_anchor_token(';');
4282         add_anchor_token(',');
4283         while (true) {
4284                 entity_t *entity = finished_declaration(ndeclaration, token.kind == '=');
4285
4286                 if (token.kind == '=') {
4287                         parse_init_declarator_rest(entity);
4288                 } else if (entity->kind == ENTITY_VARIABLE) {
4289                         /* ISO/IEC 14882:1998(E) §8.5.3:3  The initializer can be omitted
4290                          * [...] where the extern specifier is explicitly used. */
4291                         declaration_t *decl = &entity->declaration;
4292                         if (decl->storage_class != STORAGE_CLASS_EXTERN &&
4293                             is_type_reference(skip_typeref(decl->type))) {
4294                                 source_position_t const *const pos = &entity->base.source_position;
4295                                 errorf(pos, "reference '%#N' must be initialized", entity);
4296                         }
4297                 }
4298
4299                 check_variable_type_complete(entity);
4300
4301                 if (!accept(','))
4302                         break;
4303
4304                 add_anchor_token('=');
4305                 ndeclaration = parse_declarator(specifiers, flags);
4306                 rem_anchor_token('=');
4307         }
4308         rem_anchor_token(',');
4309         rem_anchor_token(';');
4310         expect(';');
4311
4312         anonymous_entity = NULL;
4313 }
4314
4315 static entity_t *finished_kr_declaration(entity_t *entity, bool is_definition)
4316 {
4317         symbol_t *symbol = entity->base.symbol;
4318         if (symbol == NULL)
4319                 return entity;
4320
4321         assert(entity->base.namespc == NAMESPACE_NORMAL);
4322         entity_t *previous_entity = get_entity(symbol, NAMESPACE_NORMAL);
4323         if (previous_entity == NULL
4324                         || previous_entity->base.parent_scope != current_scope) {
4325                 errorf(&entity->base.source_position, "expected declaration of a function parameter, found '%Y'",
4326                        symbol);
4327                 return entity;
4328         }
4329
4330         if (is_definition) {
4331                 errorf(HERE, "'%N' is initialised", entity);
4332         }
4333
4334         return record_entity(entity, false);
4335 }
4336
4337 static void parse_declaration(parsed_declaration_func finished_declaration,
4338                               declarator_flags_t      flags)
4339 {
4340         add_anchor_token(';');
4341         declaration_specifiers_t specifiers;
4342         parse_declaration_specifiers(&specifiers);
4343         rem_anchor_token(';');
4344
4345         if (token.kind == ';') {
4346                 parse_anonymous_declaration_rest(&specifiers);
4347         } else {
4348                 entity_t *entity = parse_declarator(&specifiers, flags);
4349                 parse_declaration_rest(entity, &specifiers, finished_declaration, flags);
4350         }
4351 }
4352
4353 /* §6.5.2.2:6 */
4354 static type_t *get_default_promoted_type(type_t *orig_type)
4355 {
4356         type_t *result = orig_type;
4357
4358         type_t *type = skip_typeref(orig_type);
4359         if (is_type_integer(type)) {
4360                 result = promote_integer(type);
4361         } else if (is_type_atomic(type, ATOMIC_TYPE_FLOAT)) {
4362                 result = type_double;
4363         }
4364
4365         return result;
4366 }
4367
4368 static void parse_kr_declaration_list(entity_t *entity)
4369 {
4370         if (entity->kind != ENTITY_FUNCTION)
4371                 return;
4372
4373         type_t *type = skip_typeref(entity->declaration.type);
4374         assert(is_type_function(type));
4375         if (!type->function.kr_style_parameters)
4376                 return;
4377
4378         add_anchor_token('{');
4379
4380         PUSH_SCOPE(&entity->function.parameters);
4381
4382         entity_t *parameter = entity->function.parameters.entities;
4383         for ( ; parameter != NULL; parameter = parameter->base.next) {
4384                 assert(parameter->base.parent_scope == NULL);
4385                 parameter->base.parent_scope = current_scope;
4386                 environment_push(parameter);
4387         }
4388
4389         /* parse declaration list */
4390         for (;;) {
4391                 switch (token.kind) {
4392                         DECLARATION_START
4393                         /* This covers symbols, which are no type, too, and results in
4394                          * better error messages.  The typical cases are misspelled type
4395                          * names and missing includes. */
4396                         case T_IDENTIFIER:
4397                                 parse_declaration(finished_kr_declaration, DECL_IS_PARAMETER);
4398                                 break;
4399                         default:
4400                                 goto decl_list_end;
4401                 }
4402         }
4403 decl_list_end:
4404
4405         POP_SCOPE();
4406
4407         /* update function type */
4408         type_t *new_type = duplicate_type(type);
4409
4410         function_parameter_t  *parameters = NULL;
4411         function_parameter_t **anchor     = &parameters;
4412
4413         /* did we have an earlier prototype? */
4414         entity_t *proto_type = get_entity(entity->base.symbol, NAMESPACE_NORMAL);
4415         if (proto_type != NULL && proto_type->kind != ENTITY_FUNCTION)
4416                 proto_type = NULL;
4417
4418         function_parameter_t *proto_parameter = NULL;
4419         if (proto_type != NULL) {
4420                 type_t *proto_type_type = proto_type->declaration.type;
4421                 proto_parameter         = proto_type_type->function.parameters;
4422                 /* If a K&R function definition has a variadic prototype earlier, then
4423                  * make the function definition variadic, too. This should conform to
4424                  * §6.7.5.3:15 and §6.9.1:8. */
4425                 new_type->function.variadic = proto_type_type->function.variadic;
4426         } else {
4427                 /* §6.9.1.7: A K&R style parameter list does NOT act as a function
4428                  * prototype */
4429                 new_type->function.unspecified_parameters = true;
4430         }
4431
4432         bool need_incompatible_warning = false;
4433         parameter = entity->function.parameters.entities;
4434         for (; parameter != NULL; parameter = parameter->base.next,
4435                         proto_parameter =
4436                                 proto_parameter == NULL ? NULL : proto_parameter->next) {
4437                 if (parameter->kind != ENTITY_PARAMETER)
4438                         continue;
4439
4440                 type_t *parameter_type = parameter->declaration.type;
4441                 if (parameter_type == NULL) {
4442                         source_position_t const* const pos = &parameter->base.source_position;
4443                         if (strict_mode) {
4444                                 errorf(pos, "no type specified for function '%N'", parameter);
4445                                 parameter_type = type_error_type;
4446                         } else {
4447                                 warningf(WARN_IMPLICIT_INT, pos, "no type specified for function parameter '%N', using 'int'", parameter);
4448                                 parameter_type = type_int;
4449                         }
4450                         parameter->declaration.type = parameter_type;
4451                 }
4452
4453                 semantic_parameter_incomplete(parameter);
4454
4455                 /* we need the default promoted types for the function type */
4456                 type_t *not_promoted = parameter_type;
4457                 parameter_type       = get_default_promoted_type(parameter_type);
4458
4459                 /* gcc special: if the type of the prototype matches the unpromoted
4460                  * type don't promote */
4461                 if (!strict_mode && proto_parameter != NULL) {
4462                         type_t *proto_p_type = skip_typeref(proto_parameter->type);
4463                         type_t *promo_skip   = skip_typeref(parameter_type);
4464                         type_t *param_skip   = skip_typeref(not_promoted);
4465                         if (!types_compatible(proto_p_type, promo_skip)
4466                                 && types_compatible(proto_p_type, param_skip)) {
4467                                 /* don't promote */
4468                                 need_incompatible_warning = true;
4469                                 parameter_type = not_promoted;
4470                         }
4471                 }
4472                 function_parameter_t *const function_parameter
4473                         = allocate_parameter(parameter_type);
4474
4475                 *anchor = function_parameter;
4476                 anchor  = &function_parameter->next;
4477         }
4478
4479         new_type->function.parameters = parameters;
4480         new_type = identify_new_type(new_type);
4481
4482         if (need_incompatible_warning) {
4483                 symbol_t          const *const sym  = entity->base.symbol;
4484                 source_position_t const *const pos  = &entity->base.source_position;
4485                 source_position_t const *const ppos = &proto_type->base.source_position;
4486                 warningf(WARN_OTHER, pos, "declaration '%#N' is incompatible with '%#T' (declared %P)", proto_type, new_type, sym, ppos);
4487         }
4488         entity->declaration.type = new_type;
4489
4490         rem_anchor_token('{');
4491 }
4492
4493 static bool first_err = true;
4494
4495 /**
4496  * When called with first_err set, prints the name of the current function,
4497  * else does noting.
4498  */
4499 static void print_in_function(void)
4500 {
4501         if (first_err) {
4502                 first_err = false;
4503                 char const *const file = current_function->base.base.source_position.input_name;
4504                 diagnosticf("%s: In '%N':\n", file, (entity_t const*)current_function);
4505         }
4506 }
4507
4508 /**
4509  * Check if all labels are defined in the current function.
4510  * Check if all labels are used in the current function.
4511  */
4512 static void check_labels(void)
4513 {
4514         for (const goto_statement_t *goto_statement = goto_first;
4515             goto_statement != NULL;
4516             goto_statement = goto_statement->next) {
4517                 label_t *label = goto_statement->label;
4518                 if (label->base.source_position.input_name == NULL) {
4519                         print_in_function();
4520                         source_position_t const *const pos = &goto_statement->base.source_position;
4521                         errorf(pos, "'%N' used but not defined", (entity_t const*)label);
4522                  }
4523         }
4524
4525         if (is_warn_on(WARN_UNUSED_LABEL)) {
4526                 for (const label_statement_t *label_statement = label_first;
4527                          label_statement != NULL;
4528                          label_statement = label_statement->next) {
4529                         label_t *label = label_statement->label;
4530
4531                         if (! label->used) {
4532                                 print_in_function();
4533                                 source_position_t const *const pos = &label_statement->base.source_position;
4534                                 warningf(WARN_UNUSED_LABEL, pos, "'%N' defined but not used", (entity_t const*)label);
4535                         }
4536                 }
4537         }
4538 }
4539
4540 static void warn_unused_entity(warning_t const why, entity_t *entity, entity_t *const last)
4541 {
4542         entity_t const *const end = last != NULL ? last->base.next : NULL;
4543         for (; entity != end; entity = entity->base.next) {
4544                 if (!is_declaration(entity))
4545                         continue;
4546
4547                 declaration_t *declaration = &entity->declaration;
4548                 if (declaration->implicit)
4549                         continue;
4550
4551                 if (!declaration->used) {
4552                         print_in_function();
4553                         warningf(why, &entity->base.source_position, "'%N' is unused", entity);
4554                 } else if (entity->kind == ENTITY_VARIABLE && !entity->variable.read) {
4555                         print_in_function();
4556                         warningf(why, &entity->base.source_position, "'%N' is never read", entity);
4557                 }
4558         }
4559 }
4560
4561 static void check_unused_variables(statement_t *const stmt, void *const env)
4562 {
4563         (void)env;
4564
4565         switch (stmt->kind) {
4566                 case STATEMENT_DECLARATION: {
4567                         declaration_statement_t const *const decls = &stmt->declaration;
4568                         warn_unused_entity(WARN_UNUSED_VARIABLE, decls->declarations_begin, decls->declarations_end);
4569                         return;
4570                 }
4571
4572                 case STATEMENT_FOR:
4573                         warn_unused_entity(WARN_UNUSED_VARIABLE, stmt->fors.scope.entities, NULL);
4574                         return;
4575
4576                 default:
4577                         return;
4578         }
4579 }
4580
4581 /**
4582  * Check declarations of current_function for unused entities.
4583  */
4584 static void check_declarations(void)
4585 {
4586         if (is_warn_on(WARN_UNUSED_PARAMETER)) {
4587                 const scope_t *scope = &current_function->parameters;
4588                 warn_unused_entity(WARN_UNUSED_PARAMETER, scope->entities, NULL);
4589         }
4590         if (is_warn_on(WARN_UNUSED_VARIABLE)) {
4591                 walk_statements(current_function->body, check_unused_variables, NULL);
4592         }
4593 }
4594
4595 static int determine_truth(expression_t const* const cond)
4596 {
4597         return
4598                 is_constant_expression(cond) != EXPR_CLASS_CONSTANT ? 0 :
4599                 fold_constant_to_bool(cond)                         ? 1 :
4600                 -1;
4601 }
4602
4603 static void check_reachable(statement_t *);
4604 static bool reaches_end;
4605
4606 static bool expression_returns(expression_t const *const expr)
4607 {
4608         switch (expr->kind) {
4609                 case EXPR_CALL: {
4610                         expression_t const *const func = expr->call.function;
4611                         type_t       const *const type = skip_typeref(func->base.type);
4612                         if (type->kind == TYPE_POINTER) {
4613                                 type_t const *const points_to
4614                                         = skip_typeref(type->pointer.points_to);
4615                                 if (points_to->kind == TYPE_FUNCTION
4616                                     && points_to->function.modifiers & DM_NORETURN)
4617                                         return false;
4618                         }
4619
4620                         if (!expression_returns(func))
4621                                 return false;
4622
4623                         for (call_argument_t const* arg = expr->call.arguments; arg != NULL; arg = arg->next) {
4624                                 if (!expression_returns(arg->expression))
4625                                         return false;
4626                         }
4627
4628                         return true;
4629                 }
4630
4631                 case EXPR_REFERENCE:
4632                 case EXPR_ENUM_CONSTANT:
4633                 case EXPR_LITERAL_CASES:
4634                 case EXPR_LITERAL_CHARACTER:
4635                 case EXPR_STRING_LITERAL:
4636                 case EXPR_COMPOUND_LITERAL: // TODO descend into initialisers
4637                 case EXPR_LABEL_ADDRESS:
4638                 case EXPR_CLASSIFY_TYPE:
4639                 case EXPR_SIZEOF: // TODO handle obscure VLA case
4640                 case EXPR_ALIGNOF:
4641                 case EXPR_FUNCNAME:
4642                 case EXPR_BUILTIN_CONSTANT_P:
4643                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
4644                 case EXPR_OFFSETOF:
4645                 case EXPR_ERROR:
4646                         return true;
4647
4648                 case EXPR_STATEMENT: {
4649                         bool old_reaches_end = reaches_end;
4650                         reaches_end = false;
4651                         check_reachable(expr->statement.statement);
4652                         bool returns = reaches_end;
4653                         reaches_end = old_reaches_end;
4654                         return returns;
4655                 }
4656
4657                 case EXPR_CONDITIONAL:
4658                         // TODO handle constant expression
4659
4660                         if (!expression_returns(expr->conditional.condition))
4661                                 return false;
4662
4663                         if (expr->conditional.true_expression != NULL
4664                                         && expression_returns(expr->conditional.true_expression))
4665                                 return true;
4666
4667                         return expression_returns(expr->conditional.false_expression);
4668
4669                 case EXPR_SELECT:
4670                         return expression_returns(expr->select.compound);
4671
4672                 case EXPR_ARRAY_ACCESS:
4673                         return
4674                                 expression_returns(expr->array_access.array_ref) &&
4675                                 expression_returns(expr->array_access.index);
4676
4677                 case EXPR_VA_START:
4678                         return expression_returns(expr->va_starte.ap);
4679
4680                 case EXPR_VA_ARG:
4681                         return expression_returns(expr->va_arge.ap);
4682
4683                 case EXPR_VA_COPY:
4684                         return expression_returns(expr->va_copye.src);
4685
4686                 case EXPR_UNARY_CASES_MANDATORY:
4687                         return expression_returns(expr->unary.value);
4688
4689                 case EXPR_UNARY_THROW:
4690                         return false;
4691
4692                 case EXPR_BINARY_CASES:
4693                         // TODO handle constant lhs of && and ||
4694                         return
4695                                 expression_returns(expr->binary.left) &&
4696                                 expression_returns(expr->binary.right);
4697         }
4698
4699         panic("unhandled expression");
4700 }
4701
4702 static bool initializer_returns(initializer_t const *const init)
4703 {
4704         switch (init->kind) {
4705                 case INITIALIZER_VALUE:
4706                         return expression_returns(init->value.value);
4707
4708                 case INITIALIZER_LIST: {
4709                         initializer_t * const*       i       = init->list.initializers;
4710                         initializer_t * const* const end     = i + init->list.len;
4711                         bool                         returns = true;
4712                         for (; i != end; ++i) {
4713                                 if (!initializer_returns(*i))
4714                                         returns = false;
4715                         }
4716                         return returns;
4717                 }
4718
4719                 case INITIALIZER_STRING:
4720                 case INITIALIZER_DESIGNATOR: // designators have no payload
4721                         return true;
4722         }
4723         panic("unhandled initializer");
4724 }
4725
4726 static bool noreturn_candidate;
4727
4728 static void check_reachable(statement_t *const stmt)
4729 {
4730         if (stmt->base.reachable)
4731                 return;
4732         if (stmt->kind != STATEMENT_DO_WHILE)
4733                 stmt->base.reachable = true;
4734
4735         statement_t *last = stmt;
4736         statement_t *next;
4737         switch (stmt->kind) {
4738                 case STATEMENT_ERROR:
4739                 case STATEMENT_EMPTY:
4740                 case STATEMENT_ASM:
4741                         next = stmt->base.next;
4742                         break;
4743
4744                 case STATEMENT_DECLARATION: {
4745                         declaration_statement_t const *const decl = &stmt->declaration;
4746                         entity_t                const *      ent  = decl->declarations_begin;
4747                         entity_t                const *const last_decl = decl->declarations_end;
4748                         if (ent != NULL) {
4749                                 for (;; ent = ent->base.next) {
4750                                         if (ent->kind                 == ENTITY_VARIABLE &&
4751                                             ent->variable.initializer != NULL            &&
4752                                             !initializer_returns(ent->variable.initializer)) {
4753                                                 return;
4754                                         }
4755                                         if (ent == last_decl)
4756                                                 break;
4757                                 }
4758                         }
4759                         next = stmt->base.next;
4760                         break;
4761                 }
4762
4763                 case STATEMENT_COMPOUND:
4764                         next = stmt->compound.statements;
4765                         if (next == NULL)
4766                                 next = stmt->base.next;
4767                         break;
4768
4769                 case STATEMENT_RETURN: {
4770                         expression_t const *const val = stmt->returns.value;
4771                         if (val == NULL || expression_returns(val))
4772                                 noreturn_candidate = false;
4773                         return;
4774                 }
4775
4776                 case STATEMENT_IF: {
4777                         if_statement_t const *const ifs  = &stmt->ifs;
4778                         expression_t   const *const cond = ifs->condition;
4779
4780                         if (!expression_returns(cond))
4781                                 return;
4782
4783                         int const val = determine_truth(cond);
4784
4785                         if (val >= 0)
4786                                 check_reachable(ifs->true_statement);
4787
4788                         if (val > 0)
4789                                 return;
4790
4791                         if (ifs->false_statement != NULL) {
4792                                 check_reachable(ifs->false_statement);
4793                                 return;
4794                         }
4795
4796                         next = stmt->base.next;
4797                         break;
4798                 }
4799
4800                 case STATEMENT_SWITCH: {
4801                         switch_statement_t const *const switchs = &stmt->switchs;
4802                         expression_t       const *const expr    = switchs->expression;
4803
4804                         if (!expression_returns(expr))
4805                                 return;
4806
4807                         if (is_constant_expression(expr) == EXPR_CLASS_CONSTANT) {
4808                                 ir_tarval              *const val      = fold_constant_to_tarval(expr);
4809                                 case_label_statement_t *      defaults = NULL;
4810                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4811                                         if (i->expression == NULL) {
4812                                                 defaults = i;
4813                                                 continue;
4814                                         }
4815
4816                                         if (i->first_case == val || i->last_case == val ||
4817                                                 ((tarval_cmp(i->first_case, val) & ir_relation_less_equal)
4818                                             && (tarval_cmp(val, i->last_case) & ir_relation_less_equal))) {
4819                                                 check_reachable((statement_t*)i);
4820                                                 return;
4821                                         }
4822                                 }
4823
4824                                 if (defaults != NULL) {
4825                                         check_reachable((statement_t*)defaults);
4826                                         return;
4827                                 }
4828                         } else {
4829                                 bool has_default = false;
4830                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4831                                         if (i->expression == NULL)
4832                                                 has_default = true;
4833
4834                                         check_reachable((statement_t*)i);
4835                                 }
4836
4837                                 if (has_default)
4838                                         return;
4839                         }
4840
4841                         next = stmt->base.next;
4842                         break;
4843                 }
4844
4845                 case STATEMENT_EXPRESSION: {
4846                         /* Check for noreturn function call */
4847                         expression_t const *const expr = stmt->expression.expression;
4848                         if (!expression_returns(expr))
4849                                 return;
4850
4851                         next = stmt->base.next;
4852                         break;
4853                 }
4854
4855                 case STATEMENT_CONTINUE:
4856                         for (statement_t *parent = stmt;;) {
4857                                 parent = parent->base.parent;
4858                                 if (parent == NULL) /* continue not within loop */
4859                                         return;
4860
4861                                 next = parent;
4862                                 switch (parent->kind) {
4863                                         case STATEMENT_DO_WHILE: goto continue_do_while;
4864                                         case STATEMENT_FOR:      goto continue_for;
4865
4866                                         default: break;
4867                                 }
4868                         }
4869
4870                 case STATEMENT_BREAK:
4871                         for (statement_t *parent = stmt;;) {
4872                                 parent = parent->base.parent;
4873                                 if (parent == NULL) /* break not within loop/switch */
4874                                         return;
4875
4876                                 switch (parent->kind) {
4877                                         case STATEMENT_SWITCH:
4878                                         case STATEMENT_DO_WHILE:
4879                                         case STATEMENT_FOR:
4880                                                 last = parent;
4881                                                 next = parent->base.next;
4882                                                 goto found_break_parent;
4883
4884                                         default: break;
4885                                 }
4886                         }
4887 found_break_parent:
4888                         break;
4889
4890                 case STATEMENT_COMPUTED_GOTO: {
4891                         if (!expression_returns(stmt->computed_goto.expression))
4892                                 return;
4893
4894                         statement_t *parent = stmt->base.parent;
4895                         if (parent == NULL) /* top level goto */
4896                                 return;
4897                         next = parent;
4898                         break;
4899                 }
4900
4901                 case STATEMENT_GOTO:
4902                         next = stmt->gotos.label->statement;
4903                         if (next == NULL) /* missing label */
4904                                 return;
4905                         break;
4906
4907                 case STATEMENT_LABEL:
4908                         next = stmt->label.statement;
4909                         break;
4910
4911                 case STATEMENT_CASE_LABEL:
4912                         next = stmt->case_label.statement;
4913                         break;
4914
4915                 case STATEMENT_DO_WHILE:
4916                         next = stmt->do_while.body;
4917                         break;
4918
4919                 case STATEMENT_FOR: {
4920                         for_statement_t *const fors = &stmt->fors;
4921
4922                         if (fors->condition_reachable)
4923                                 return;
4924                         fors->condition_reachable = true;
4925
4926                         expression_t const *const cond = fors->condition;
4927
4928                         int val;
4929                         if (cond == NULL) {
4930                                 val = 1;
4931                         } else if (expression_returns(cond)) {
4932                                 val = determine_truth(cond);
4933                         } else {
4934                                 return;
4935                         }
4936
4937                         if (val >= 0)
4938                                 check_reachable(fors->body);
4939
4940                         if (val > 0)
4941                                 return;
4942
4943                         next = stmt->base.next;
4944                         break;
4945                 }
4946
4947                 case STATEMENT_MS_TRY: {
4948                         ms_try_statement_t const *const ms_try = &stmt->ms_try;
4949                         check_reachable(ms_try->try_statement);
4950                         next = ms_try->final_statement;
4951                         break;
4952                 }
4953
4954                 case STATEMENT_LEAVE: {
4955                         statement_t *parent = stmt;
4956                         for (;;) {
4957                                 parent = parent->base.parent;
4958                                 if (parent == NULL) /* __leave not within __try */
4959                                         return;
4960
4961                                 if (parent->kind == STATEMENT_MS_TRY) {
4962                                         last = parent;
4963                                         next = parent->ms_try.final_statement;
4964                                         break;
4965                                 }
4966                         }
4967                         break;
4968                 }
4969
4970                 default:
4971                         panic("invalid statement kind");
4972         }
4973
4974         while (next == NULL) {
4975                 next = last->base.parent;
4976                 if (next == NULL) {
4977                         noreturn_candidate = false;
4978
4979                         type_t *const type = skip_typeref(current_function->base.type);
4980                         assert(is_type_function(type));
4981                         type_t *const ret  = skip_typeref(type->function.return_type);
4982                         if (!is_type_void(ret) &&
4983                             is_type_valid(ret) &&
4984                             !is_main(current_entity)) {
4985                                 source_position_t const *const pos = &stmt->base.source_position;
4986                                 warningf(WARN_RETURN_TYPE, pos, "control reaches end of non-void function");
4987                         }
4988                         return;
4989                 }
4990
4991                 switch (next->kind) {
4992                         case STATEMENT_ERROR:
4993                         case STATEMENT_EMPTY:
4994                         case STATEMENT_DECLARATION:
4995                         case STATEMENT_EXPRESSION:
4996                         case STATEMENT_ASM:
4997                         case STATEMENT_RETURN:
4998                         case STATEMENT_CONTINUE:
4999                         case STATEMENT_BREAK:
5000                         case STATEMENT_COMPUTED_GOTO:
5001                         case STATEMENT_GOTO:
5002                         case STATEMENT_LEAVE:
5003                                 panic("invalid control flow in function");
5004
5005                         case STATEMENT_COMPOUND:
5006                                 if (next->compound.stmt_expr) {
5007                                         reaches_end = true;
5008                                         return;
5009                                 }
5010                                 /* FALLTHROUGH */
5011                         case STATEMENT_IF:
5012                         case STATEMENT_SWITCH:
5013                         case STATEMENT_LABEL:
5014                         case STATEMENT_CASE_LABEL:
5015                                 last = next;
5016                                 next = next->base.next;
5017                                 break;
5018
5019                         case STATEMENT_DO_WHILE: {
5020 continue_do_while:
5021                                 if (next->base.reachable)
5022                                         return;
5023                                 next->base.reachable = true;
5024
5025                                 do_while_statement_t const *const dw   = &next->do_while;
5026                                 expression_t         const *const cond = dw->condition;
5027
5028                                 if (!expression_returns(cond))
5029                                         return;
5030
5031                                 int const val = determine_truth(cond);
5032
5033                                 if (val >= 0)
5034                                         check_reachable(dw->body);
5035
5036                                 if (val > 0)
5037                                         return;
5038
5039                                 last = next;
5040                                 next = next->base.next;
5041                                 break;
5042                         }
5043
5044                         case STATEMENT_FOR: {
5045 continue_for:;
5046                                 for_statement_t *const fors = &next->fors;
5047
5048                                 fors->step_reachable = true;
5049
5050                                 if (fors->condition_reachable)
5051                                         return;
5052                                 fors->condition_reachable = true;
5053
5054                                 expression_t const *const cond = fors->condition;
5055
5056                                 int val;
5057                                 if (cond == NULL) {
5058                                         val = 1;
5059                                 } else if (expression_returns(cond)) {
5060                                         val = determine_truth(cond);
5061                                 } else {
5062                                         return;
5063                                 }
5064
5065                                 if (val >= 0)
5066                                         check_reachable(fors->body);
5067
5068                                 if (val > 0)
5069                                         return;
5070
5071                                 last = next;
5072                                 next = next->base.next;
5073                                 break;
5074                         }
5075
5076                         case STATEMENT_MS_TRY:
5077                                 last = next;
5078                                 next = next->ms_try.final_statement;
5079                                 break;
5080                 }
5081         }
5082
5083         check_reachable(next);
5084 }
5085
5086 static void check_unreachable(statement_t* const stmt, void *const env)
5087 {
5088         (void)env;
5089
5090         switch (stmt->kind) {
5091                 case STATEMENT_DO_WHILE:
5092                         if (!stmt->base.reachable) {
5093                                 expression_t const *const cond = stmt->do_while.condition;
5094                                 if (determine_truth(cond) >= 0) {
5095                                         source_position_t const *const pos = &cond->base.source_position;
5096                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of do-while-loop is unreachable");
5097                                 }
5098                         }
5099                         return;
5100
5101                 case STATEMENT_FOR: {
5102                         for_statement_t const* const fors = &stmt->fors;
5103
5104                         // if init and step are unreachable, cond is unreachable, too
5105                         if (!stmt->base.reachable && !fors->step_reachable) {
5106                                 goto warn_unreachable;
5107                         } else {
5108                                 if (!stmt->base.reachable && fors->initialisation != NULL) {
5109                                         source_position_t const *const pos = &fors->initialisation->base.source_position;
5110                                         warningf(WARN_UNREACHABLE_CODE, pos, "initialisation of for-statement is unreachable");
5111                                 }
5112
5113                                 if (!fors->condition_reachable && fors->condition != NULL) {
5114                                         source_position_t const *const pos = &fors->condition->base.source_position;
5115                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of for-statement is unreachable");
5116                                 }
5117
5118                                 if (!fors->step_reachable && fors->step != NULL) {
5119                                         source_position_t const *const pos = &fors->step->base.source_position;
5120                                         warningf(WARN_UNREACHABLE_CODE, pos, "step of for-statement is unreachable");
5121                                 }
5122                         }
5123                         return;
5124                 }
5125
5126                 case STATEMENT_COMPOUND:
5127                         if (stmt->compound.statements != NULL)
5128                                 return;
5129                         goto warn_unreachable;
5130
5131                 case STATEMENT_DECLARATION: {
5132                         /* Only warn if there is at least one declarator with an initializer.
5133                          * This typically occurs in switch statements. */
5134                         declaration_statement_t const *const decl = &stmt->declaration;
5135                         entity_t                const *      ent  = decl->declarations_begin;
5136                         entity_t                const *const last = decl->declarations_end;
5137                         if (ent != NULL) {
5138                                 for (;; ent = ent->base.next) {
5139                                         if (ent->kind                 == ENTITY_VARIABLE &&
5140                                                         ent->variable.initializer != NULL) {
5141                                                 goto warn_unreachable;
5142                                         }
5143                                         if (ent == last)
5144                                                 return;
5145                                 }
5146                         }
5147                 }
5148
5149                 default:
5150 warn_unreachable:
5151                         if (!stmt->base.reachable) {
5152                                 source_position_t const *const pos = &stmt->base.source_position;
5153                                 warningf(WARN_UNREACHABLE_CODE, pos, "statement is unreachable");
5154                         }
5155                         return;
5156         }
5157 }
5158
5159 static bool is_main(entity_t *entity)
5160 {
5161         static symbol_t *sym_main = NULL;
5162         if (sym_main == NULL) {
5163                 sym_main = symbol_table_insert("main");
5164         }
5165
5166         if (entity->base.symbol != sym_main)
5167                 return false;
5168         /* must be in outermost scope */
5169         if (entity->base.parent_scope != file_scope)
5170                 return false;
5171
5172         return true;
5173 }
5174
5175 static void prepare_main_collect2(entity_t*);
5176
5177 static void parse_external_declaration(void)
5178 {
5179         /* function-definitions and declarations both start with declaration
5180          * specifiers */
5181         add_anchor_token(';');
5182         declaration_specifiers_t specifiers;
5183         parse_declaration_specifiers(&specifiers);
5184         rem_anchor_token(';');
5185
5186         /* must be a declaration */
5187         if (token.kind == ';') {
5188                 parse_anonymous_declaration_rest(&specifiers);
5189                 return;
5190         }
5191
5192         add_anchor_token(',');
5193         add_anchor_token('=');
5194         add_anchor_token(';');
5195         add_anchor_token('{');
5196
5197         /* declarator is common to both function-definitions and declarations */
5198         entity_t *ndeclaration = parse_declarator(&specifiers, DECL_FLAGS_NONE);
5199
5200         rem_anchor_token('{');
5201         rem_anchor_token(';');
5202         rem_anchor_token('=');
5203         rem_anchor_token(',');
5204
5205         /* must be a declaration */
5206         switch (token.kind) {
5207                 case ',':
5208                 case ';':
5209                 case '=':
5210                         parse_declaration_rest(ndeclaration, &specifiers, record_entity,
5211                                         DECL_FLAGS_NONE);
5212                         return;
5213         }
5214
5215         /* must be a function definition */
5216         parse_kr_declaration_list(ndeclaration);
5217
5218         if (token.kind != '{') {
5219                 parse_error_expected("while parsing function definition", '{', NULL);
5220                 eat_until_matching_token(';');
5221                 return;
5222         }
5223
5224         assert(is_declaration(ndeclaration));
5225         type_t *const orig_type = ndeclaration->declaration.type;
5226         type_t *      type      = skip_typeref(orig_type);
5227
5228         if (!is_type_function(type)) {
5229                 if (is_type_valid(type)) {
5230                         errorf(HERE, "declarator '%#N' has a body but is not a function type", ndeclaration);
5231                 }
5232                 eat_block();
5233                 return;
5234         }
5235
5236         source_position_t const *const pos = &ndeclaration->base.source_position;
5237         if (is_typeref(orig_type)) {
5238                 /* §6.9.1:2 */
5239                 errorf(pos, "type of function definition '%#N' is a typedef", ndeclaration);
5240         }
5241
5242         if (is_type_compound(skip_typeref(type->function.return_type))) {
5243                 warningf(WARN_AGGREGATE_RETURN, pos, "'%N' returns an aggregate", ndeclaration);
5244         }
5245         if (type->function.unspecified_parameters) {
5246                 warningf(WARN_OLD_STYLE_DEFINITION, pos, "old-style definition of '%N'", ndeclaration);
5247         } else {
5248                 warningf(WARN_TRADITIONAL, pos, "traditional C rejects ISO C style definition of '%N'", ndeclaration);
5249         }
5250
5251         /* §6.7.5.3:14 a function definition with () means no
5252          * parameters (and not unspecified parameters) */
5253         if (type->function.unspecified_parameters &&
5254                         type->function.parameters == NULL) {
5255                 type_t *copy                          = duplicate_type(type);
5256                 copy->function.unspecified_parameters = false;
5257                 type                                  = identify_new_type(copy);
5258
5259                 ndeclaration->declaration.type = type;
5260         }
5261
5262         entity_t *const entity = record_entity(ndeclaration, true);
5263         assert(entity->kind == ENTITY_FUNCTION);
5264         assert(ndeclaration->kind == ENTITY_FUNCTION);
5265
5266         function_t *const function = &entity->function;
5267         if (ndeclaration != entity) {
5268                 function->parameters = ndeclaration->function.parameters;
5269         }
5270
5271         PUSH_SCOPE(&function->parameters);
5272
5273         entity_t *parameter = function->parameters.entities;
5274         for (; parameter != NULL; parameter = parameter->base.next) {
5275                 if (parameter->base.parent_scope == &ndeclaration->function.parameters) {
5276                         parameter->base.parent_scope = current_scope;
5277                 }
5278                 assert(parameter->base.parent_scope == NULL
5279                                 || parameter->base.parent_scope == current_scope);
5280                 parameter->base.parent_scope = current_scope;
5281                 if (parameter->base.symbol == NULL) {
5282                         errorf(&parameter->base.source_position, "parameter name omitted");
5283                         continue;
5284                 }
5285                 environment_push(parameter);
5286         }
5287
5288         if (function->body != NULL) {
5289                 parser_error_multiple_definition(entity, HERE);
5290                 eat_block();
5291         } else {
5292                 /* parse function body */
5293                 int         label_stack_top      = label_top();
5294                 function_t *old_current_function = current_function;
5295                 current_function                 = function;
5296                 PUSH_CURRENT_ENTITY(entity);
5297                 PUSH_PARENT(NULL);
5298
5299                 goto_first   = NULL;
5300                 goto_anchor  = &goto_first;
5301                 label_first  = NULL;
5302                 label_anchor = &label_first;
5303
5304                 statement_t *const body = parse_compound_statement(false);
5305                 function->body = body;
5306                 first_err = true;
5307                 check_labels();
5308                 check_declarations();
5309                 if (is_warn_on(WARN_RETURN_TYPE)      ||
5310                     is_warn_on(WARN_UNREACHABLE_CODE) ||
5311                     (is_warn_on(WARN_MISSING_NORETURN) && !(function->base.modifiers & DM_NORETURN))) {
5312                         noreturn_candidate = true;
5313                         check_reachable(body);
5314                         if (is_warn_on(WARN_UNREACHABLE_CODE))
5315                                 walk_statements(body, check_unreachable, NULL);
5316                         if (noreturn_candidate &&
5317                             !(function->base.modifiers & DM_NORETURN)) {
5318                                 source_position_t const *const pos = &body->base.source_position;
5319                                 warningf(WARN_MISSING_NORETURN, pos, "function '%#N' is candidate for attribute 'noreturn'", entity);
5320                         }
5321                 }
5322
5323                 if (is_main(entity)) {
5324                         /* Force main to C linkage. */
5325                         type_t *const type = entity->declaration.type;
5326                         assert(is_type_function(type));
5327                         if (type->function.linkage != LINKAGE_C) {
5328                                 type_t *new_type           = duplicate_type(type);
5329                                 new_type->function.linkage = LINKAGE_C;
5330                                 entity->declaration.type   = identify_new_type(new_type);
5331                         }
5332
5333                         if (enable_main_collect2_hack)
5334                                 prepare_main_collect2(entity);
5335                 }
5336
5337                 POP_CURRENT_ENTITY();
5338                 POP_PARENT();
5339                 assert(current_function == function);
5340                 current_function = old_current_function;
5341                 label_pop_to(label_stack_top);
5342         }
5343
5344         POP_SCOPE();
5345 }
5346
5347 static entity_t *find_compound_entry(compound_t *compound, symbol_t *symbol)
5348 {
5349         entity_t *iter = compound->members.entities;
5350         for (; iter != NULL; iter = iter->base.next) {
5351                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5352                         continue;
5353
5354                 if (iter->base.symbol == symbol) {
5355                         return iter;
5356                 } else if (iter->base.symbol == NULL) {
5357                         /* search in anonymous structs and unions */
5358                         type_t *type = skip_typeref(iter->declaration.type);
5359                         if (is_type_compound(type)) {
5360                                 if (find_compound_entry(type->compound.compound, symbol)
5361                                                 != NULL)
5362                                         return iter;
5363                         }
5364                         continue;
5365                 }
5366         }
5367
5368         return NULL;
5369 }
5370
5371 static void check_deprecated(const source_position_t *source_position,
5372                              const entity_t *entity)
5373 {
5374         if (!is_declaration(entity))
5375                 return;
5376         if ((entity->declaration.modifiers & DM_DEPRECATED) == 0)
5377                 return;
5378
5379         source_position_t const *const epos = &entity->base.source_position;
5380         char              const *const msg  = get_deprecated_string(entity->declaration.attributes);
5381         if (msg != NULL) {
5382                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P): \"%s\"", entity, epos, msg);
5383         } else {
5384                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P)", entity, epos);
5385         }
5386 }
5387
5388
5389 static expression_t *create_select(const source_position_t *pos,
5390                                    expression_t *addr,
5391                                    type_qualifiers_t qualifiers,
5392                                                                    entity_t *entry)
5393 {
5394         assert(entry->kind == ENTITY_COMPOUND_MEMBER);
5395
5396         check_deprecated(pos, entry);
5397
5398         expression_t *select          = allocate_expression_zero(EXPR_SELECT);
5399         select->select.compound       = addr;
5400         select->select.compound_entry = entry;
5401
5402         type_t *entry_type = entry->declaration.type;
5403         type_t *res_type   = get_qualified_type(entry_type, qualifiers);
5404
5405         /* bitfields need special treatment */
5406         if (entry->compound_member.bitfield) {
5407                 unsigned bit_size = entry->compound_member.bit_size;
5408                 /* if fewer bits than an int, convert to int (see §6.3.1.1) */
5409                 if (bit_size < get_atomic_type_size(ATOMIC_TYPE_INT) * BITS_PER_BYTE) {
5410                         res_type = type_int;
5411                 }
5412         }
5413
5414         /* we always do the auto-type conversions; the & and sizeof parser contains
5415          * code to revert this! */
5416         select->base.type = automatic_type_conversion(res_type);
5417
5418
5419         return select;
5420 }
5421
5422 /**
5423  * Find entry with symbol in compound. Search anonymous structs and unions and
5424  * creates implicit select expressions for them.
5425  * Returns the adress for the innermost compound.
5426  */
5427 static expression_t *find_create_select(const source_position_t *pos,
5428                                         expression_t *addr,
5429                                         type_qualifiers_t qualifiers,
5430                                         compound_t *compound, symbol_t *symbol)
5431 {
5432         entity_t *iter = compound->members.entities;
5433         for (; iter != NULL; iter = iter->base.next) {
5434                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5435                         continue;
5436
5437                 symbol_t *iter_symbol = iter->base.symbol;
5438                 if (iter_symbol == NULL) {
5439                         type_t *type = iter->declaration.type;
5440                         if (!is_type_compound(type))
5441                                 continue;
5442
5443                         compound_t *sub_compound = type->compound.compound;
5444
5445                         if (find_compound_entry(sub_compound, symbol) == NULL)
5446                                 continue;
5447
5448                         expression_t *sub_addr = create_select(pos, addr, qualifiers, iter);
5449                         sub_addr->base.source_position = *pos;
5450                         sub_addr->base.implicit        = true;
5451                         return find_create_select(pos, sub_addr, qualifiers, sub_compound,
5452                                                   symbol);
5453                 }
5454
5455                 if (iter_symbol == symbol) {
5456                         return create_select(pos, addr, qualifiers, iter);
5457                 }
5458         }
5459
5460         return NULL;
5461 }
5462
5463 static void parse_bitfield_member(entity_t *entity)
5464 {
5465         eat(':');
5466
5467         expression_t *size = parse_constant_expression();
5468         long          size_long;
5469
5470         assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5471         type_t *type = entity->declaration.type;
5472         if (!is_type_integer(skip_typeref(type))) {
5473                 errorf(HERE, "bitfield base type '%T' is not an integer type",
5474                            type);
5475         }
5476
5477         if (is_constant_expression(size) != EXPR_CLASS_CONSTANT) {
5478                 /* error already reported by parse_constant_expression */
5479                 size_long = get_type_size(type) * 8;
5480         } else {
5481                 size_long = fold_constant_to_int(size);
5482
5483                 const symbol_t *symbol = entity->base.symbol;
5484                 const symbol_t *user_symbol
5485                         = symbol == NULL ? sym_anonymous : symbol;
5486                 unsigned bit_size = get_type_size(type) * 8;
5487                 if (size_long < 0) {
5488                         errorf(HERE, "negative width in bit-field '%Y'", user_symbol);
5489                 } else if (size_long == 0 && symbol != NULL) {
5490                         errorf(HERE, "zero width for bit-field '%Y'", user_symbol);
5491                 } else if (bit_size > 0 && (unsigned)size_long > bit_size) {
5492                         errorf(HERE, "width of bitfield '%Y' exceeds its type",
5493                                    user_symbol);
5494                 } else {
5495                         /* hope that people don't invent crazy types with more bits
5496                          * than our struct can hold */
5497                         assert(size_long <
5498                                    (1 << sizeof(entity->compound_member.bit_size)*8));
5499                 }
5500         }
5501
5502         entity->compound_member.bitfield = true;
5503         entity->compound_member.bit_size = (unsigned char)size_long;
5504 }
5505
5506 static void parse_compound_declarators(compound_t *compound,
5507                 const declaration_specifiers_t *specifiers)
5508 {
5509         add_anchor_token(';');
5510         add_anchor_token(',');
5511         do {
5512                 entity_t *entity;
5513
5514                 if (token.kind == ':') {
5515                         /* anonymous bitfield */
5516                         type_t *type = specifiers->type;
5517                         entity_t *const entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, NULL, HERE);
5518                         entity->declaration.declared_storage_class = STORAGE_CLASS_NONE;
5519                         entity->declaration.storage_class          = STORAGE_CLASS_NONE;
5520                         entity->declaration.type                   = type;
5521
5522                         parse_bitfield_member(entity);
5523
5524                         attribute_t  *attributes = parse_attributes(NULL);
5525                         attribute_t **anchor     = &attributes;
5526                         while (*anchor != NULL)
5527                                 anchor = &(*anchor)->next;
5528                         *anchor = specifiers->attributes;
5529                         if (attributes != NULL) {
5530                                 handle_entity_attributes(attributes, entity);
5531                         }
5532                         entity->declaration.attributes = attributes;
5533
5534                         append_entity(&compound->members, entity);
5535                 } else {
5536                         entity = parse_declarator(specifiers,
5537                                         DECL_MAY_BE_ABSTRACT | DECL_CREATE_COMPOUND_MEMBER);
5538                         source_position_t const *const pos = &entity->base.source_position;
5539                         if (entity->kind == ENTITY_TYPEDEF) {
5540                                 errorf(pos, "typedef not allowed as compound member");
5541                         } else {
5542                                 assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5543
5544                                 /* make sure we don't define a symbol multiple times */
5545                                 symbol_t *symbol = entity->base.symbol;
5546                                 if (symbol != NULL) {
5547                                         entity_t *prev = find_compound_entry(compound, symbol);
5548                                         if (prev != NULL) {
5549                                                 source_position_t const *const ppos = &prev->base.source_position;
5550                                                 errorf(pos, "multiple declarations of '%N' (declared %P)", entity, ppos);
5551                                         }
5552                                 }
5553
5554                                 if (token.kind == ':') {
5555                                         parse_bitfield_member(entity);
5556
5557                                         attribute_t *attributes = parse_attributes(NULL);
5558                                         handle_entity_attributes(attributes, entity);
5559                                 } else {
5560                                         type_t *orig_type = entity->declaration.type;
5561                                         type_t *type      = skip_typeref(orig_type);
5562                                         if (is_type_function(type)) {
5563                                                 errorf(pos, "'%N' must not have function type '%T'", entity, orig_type);
5564                                         } else if (is_type_incomplete(type)) {
5565                                                 /* §6.7.2.1:16 flexible array member */
5566                                                 if (!is_type_array(type)       ||
5567                                                                 token.kind          != ';' ||
5568                                                                 look_ahead(1)->kind != '}') {
5569                                                         errorf(pos, "'%N' has incomplete type '%T'", entity, orig_type);
5570                                                 } else if (compound->members.entities == NULL) {
5571                                                         errorf(pos, "flexible array member in otherwise empty struct");
5572                                                 }
5573                                         }
5574                                 }
5575
5576                                 append_entity(&compound->members, entity);
5577                         }
5578                 }
5579         } while (accept(','));
5580         rem_anchor_token(',');
5581         rem_anchor_token(';');
5582         expect(';');
5583
5584         anonymous_entity = NULL;
5585 }
5586
5587 static void parse_compound_type_entries(compound_t *compound)
5588 {
5589         eat('{');
5590         add_anchor_token('}');
5591
5592         for (;;) {
5593                 switch (token.kind) {
5594                         DECLARATION_START
5595                         case T___extension__:
5596                         case T_IDENTIFIER: {
5597                                 PUSH_EXTENSION();
5598                                 declaration_specifiers_t specifiers;
5599                                 parse_declaration_specifiers(&specifiers);
5600                                 parse_compound_declarators(compound, &specifiers);
5601                                 POP_EXTENSION();
5602                                 break;
5603                         }
5604
5605                         default:
5606                                 rem_anchor_token('}');
5607                                 expect('}');
5608                                 /* §6.7.2.1:7 */
5609                                 compound->complete = true;
5610                                 return;
5611                 }
5612         }
5613 }
5614
5615 static type_t *parse_typename(void)
5616 {
5617         declaration_specifiers_t specifiers;
5618         parse_declaration_specifiers(&specifiers);
5619         if (specifiers.storage_class != STORAGE_CLASS_NONE
5620                         || specifiers.thread_local) {
5621                 /* TODO: improve error message, user does probably not know what a
5622                  * storage class is...
5623                  */
5624                 errorf(&specifiers.source_position, "typename must not have a storage class");
5625         }
5626
5627         type_t *result = parse_abstract_declarator(specifiers.type);
5628
5629         return result;
5630 }
5631
5632
5633
5634
5635 typedef expression_t* (*parse_expression_function)(void);
5636 typedef expression_t* (*parse_expression_infix_function)(expression_t *left);
5637
5638 typedef struct expression_parser_function_t expression_parser_function_t;
5639 struct expression_parser_function_t {
5640         parse_expression_function        parser;
5641         precedence_t                     infix_precedence;
5642         parse_expression_infix_function  infix_parser;
5643 };
5644
5645 static expression_parser_function_t expression_parsers[T_LAST_TOKEN];
5646
5647 static type_t *get_string_type(string_encoding_t const enc)
5648 {
5649         bool const warn = is_warn_on(WARN_WRITE_STRINGS);
5650         switch (enc) {
5651         case STRING_ENCODING_CHAR:
5652         case STRING_ENCODING_UTF8:   return warn ? type_const_char_ptr     : type_char_ptr;
5653         case STRING_ENCODING_CHAR16: return warn ? type_char16_t_const_ptr : type_char16_t_ptr;
5654         case STRING_ENCODING_CHAR32: return warn ? type_char32_t_const_ptr : type_char32_t_ptr;
5655         case STRING_ENCODING_WIDE:   return warn ? type_const_wchar_t_ptr  : type_wchar_t_ptr;
5656         }
5657         panic("invalid string encoding");
5658 }
5659
5660 /**
5661  * Parse a string constant.
5662  */
5663 static expression_t *parse_string_literal(void)
5664 {
5665         expression_t *const expr = allocate_expression_zero(EXPR_STRING_LITERAL);
5666         expr->string_literal.value = concat_string_literals();
5667         expr->base.type            = get_string_type(expr->string_literal.value.encoding);
5668         return expr;
5669 }
5670
5671 /**
5672  * Parse a boolean constant.
5673  */
5674 static expression_t *parse_boolean_literal(bool value)
5675 {
5676         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_BOOLEAN);
5677         literal->base.type           = type_bool;
5678         literal->literal.value.begin = value ? "true" : "false";
5679         literal->literal.value.size  = value ? 4 : 5;
5680
5681         eat(value ? T_true : T_false);
5682         return literal;
5683 }
5684
5685 static void warn_traditional_suffix(char const *const suffix)
5686 {
5687         warningf(WARN_TRADITIONAL, HERE, "traditional C rejects the '%s' suffix", suffix);
5688 }
5689
5690 static void check_integer_suffix(expression_t *const expr, char const *const suffix)
5691 {
5692         unsigned     spec = SPECIFIER_NONE;
5693         char const  *c    = suffix;
5694         for (;;) {
5695                 specifiers_t add;
5696                 if (*c == 'L' || *c == 'l') {
5697                         add = SPECIFIER_LONG;
5698                         if (*c == c[1]) {
5699                                 add |= SPECIFIER_LONG_LONG;
5700                                 ++c;
5701                         }
5702                 } else if (*c == 'U' || *c == 'u') {
5703                         add = SPECIFIER_UNSIGNED;
5704                 } else {
5705                         break;
5706                 }
5707                 ++c;
5708                 if (spec & add)
5709                         goto error;
5710                 spec |= add;
5711         }
5712
5713         if (*c == '\0') {
5714                 type_t *type;
5715                 switch (spec) {
5716                 case SPECIFIER_NONE:                                            type = type_int;                break;
5717                 case                      SPECIFIER_LONG:                       type = type_long;               break;
5718                 case                      SPECIFIER_LONG | SPECIFIER_LONG_LONG: type = type_long_long;          break;
5719                 case SPECIFIER_UNSIGNED:                                        type = type_unsigned_int;       break;
5720                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:                       type = type_unsigned_long;      break;
5721                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG: type = type_unsigned_long_long; break;
5722                 default: panic("inconsistent suffix");
5723                 }
5724                 if (spec != SPECIFIER_NONE && spec != SPECIFIER_LONG) {
5725                         warn_traditional_suffix(suffix);
5726                 }
5727                 expr->base.type = type;
5728                 /* Integer type depends on the size of the number and the size
5729                  * representable by the types. The backend/codegeneration has to
5730                  * determine that. */
5731                 determine_literal_type(&expr->literal);
5732         } else {
5733 error:
5734                 errorf(HERE, "invalid suffix '%s' on integer constant", suffix);
5735         }
5736 }
5737
5738 static void check_floatingpoint_suffix(expression_t *const expr, char const *const suffix)
5739 {
5740         type_t     *type;
5741         char const *c    = suffix;
5742         switch (*c) {
5743         case 'F':
5744         case 'f': type = type_float;       ++c; break;
5745         case 'L':
5746         case 'l': type = type_long_double; ++c; break;
5747         default:  type = type_double;           break;
5748         }
5749
5750         if (*c == '\0') {
5751                 expr->base.type = type;
5752                 if (suffix[0] != '\0') {
5753                         warn_traditional_suffix(suffix);
5754                 }
5755         } else {
5756                 errorf(HERE, "invalid suffix '%s' on floatingpoint constant", suffix);
5757         }
5758 }
5759
5760 static expression_t *parse_number_literal(void)
5761 {
5762         string_t const *const str      = &token.literal.string;
5763         char     const *      i        = str->begin;
5764         unsigned              digits   = 0;
5765         bool                  is_float = false;
5766
5767         /* Parse base prefix. */
5768         unsigned base;
5769         if (*i == '0') {
5770                 switch (*++i) {
5771                 case 'B': case 'b': base =  2; ++i;               break;
5772                 case 'X': case 'x': base = 16; ++i;               break;
5773                 default:            base =  8; digits |= 1U << 0; break;
5774                 }
5775         } else {
5776                 base = 10;
5777         }
5778
5779         /* Parse mantissa. */
5780         for (;; ++i) {
5781                 unsigned digit;
5782                 switch (*i) {
5783                 case '.':
5784                         if (is_float) {
5785                                 errorf(HERE, "multiple decimal points in %K", &token);
5786                                 i = 0;
5787                                 goto done;
5788                         }
5789                         is_float = true;
5790                         if (base == 8)
5791                                 base = 10;
5792                         continue;
5793
5794                 case '0':           digit =  0; break;
5795                 case '1':           digit =  1; break;
5796                 case '2':           digit =  2; break;
5797                 case '3':           digit =  3; break;
5798                 case '4':           digit =  4; break;
5799                 case '5':           digit =  5; break;
5800                 case '6':           digit =  6; break;
5801                 case '7':           digit =  7; break;
5802                 case '8':           digit =  8; break;
5803                 case '9':           digit =  9; break;
5804                 case 'A': case 'a': digit = 10; break;
5805                 case 'B': case 'b': digit = 11; break;
5806                 case 'C': case 'c': digit = 12; break;
5807                 case 'D': case 'd': digit = 13; break;
5808                 case 'E': case 'e': digit = 14; break;
5809                 case 'F': case 'f': digit = 15; break;
5810
5811                 default: goto done_mantissa;
5812                 }
5813
5814                 if (digit >= 10 && base != 16)
5815                         goto done_mantissa;
5816
5817                 digits |= 1U << digit;
5818         }
5819 done_mantissa:
5820
5821         /* Parse exponent. */
5822         switch (base) {
5823         case 2:
5824                 if (is_float)
5825                         errorf(HERE, "binary floating %K not allowed", &token);
5826                 break;
5827
5828         case  8:
5829         case 10:
5830                 if (*i == 'E' || *i == 'e') {
5831                         base = 10;
5832                         goto parse_exponent;
5833                 }
5834                 break;
5835
5836         case 16:
5837                 if (*i == 'P' || *i == 'p') {
5838 parse_exponent:
5839                         ++i;
5840                         is_float = true;
5841
5842                         if (*i == '-' || *i == '+')
5843                                 ++i;
5844
5845                         if (isdigit(*i)) {
5846                                 do {
5847                                         ++i;
5848                                 } while (isdigit(*i));
5849                         } else {
5850                                 errorf(HERE, "exponent of %K has no digits", &token);
5851                         }
5852                 } else if (is_float) {
5853                         errorf(HERE, "hexadecimal floating %K requires an exponent", &token);
5854                         i = 0;
5855                 }
5856                 break;
5857
5858         default:
5859                 panic("invalid base");
5860         }
5861
5862 done:;
5863         expression_t *const expr = allocate_expression_zero(is_float ? EXPR_LITERAL_FLOATINGPOINT : EXPR_LITERAL_INTEGER);
5864         expr->literal.value = *str;
5865
5866         if (i) {
5867                 if (digits == 0) {
5868                         errorf(HERE, "%K has no digits", &token);
5869                 } else if (digits & ~((1U << base) - 1)) {
5870                         errorf(HERE, "invalid digit in %K", &token);
5871                 } else {
5872                         expr->literal.suffix = i;
5873                         if (is_float) {
5874                                 check_floatingpoint_suffix(expr, i);
5875                         } else {
5876                                 check_integer_suffix(expr, i);
5877                         }
5878                 }
5879         }
5880
5881         eat(T_NUMBER);
5882         return expr;
5883 }
5884
5885 /**
5886  * Parse a character constant.
5887  */
5888 static expression_t *parse_character_constant(void)
5889 {
5890         expression_t *const literal = allocate_expression_zero(EXPR_LITERAL_CHARACTER);
5891         literal->string_literal.value = token.literal.string;
5892
5893         size_t const size = get_string_len(&token.literal.string);
5894         switch (token.literal.string.encoding) {
5895         case STRING_ENCODING_CHAR:
5896         case STRING_ENCODING_UTF8:
5897                 literal->base.type = c_mode & _CXX ? type_char : type_int;
5898                 if (size > 1) {
5899                         if (!GNU_MODE && !(c_mode & _C99)) {
5900                                 errorf(HERE, "more than 1 character in character constant");
5901                         } else {
5902                                 literal->base.type = type_int;
5903                                 warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5904                         }
5905                 }
5906                 break;
5907
5908         case STRING_ENCODING_CHAR16: literal->base.type = type_char16_t; goto warn_multi;
5909         case STRING_ENCODING_CHAR32: literal->base.type = type_char32_t; goto warn_multi;
5910         case STRING_ENCODING_WIDE:   literal->base.type = type_wchar_t;  goto warn_multi;
5911 warn_multi:
5912                 if (size > 1) {
5913                         warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5914                 }
5915                 break;
5916         }
5917
5918         eat(T_CHARACTER_CONSTANT);
5919         return literal;
5920 }
5921
5922 static entity_t *create_implicit_function(symbol_t *symbol, source_position_t const *const pos)
5923 {
5924         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
5925         ntype->function.return_type            = type_int;
5926         ntype->function.unspecified_parameters = true;
5927         ntype->function.linkage                = LINKAGE_C;
5928         type_t *type                           = identify_new_type(ntype);
5929
5930         entity_t *const entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, symbol, pos);
5931         entity->declaration.storage_class          = STORAGE_CLASS_EXTERN;
5932         entity->declaration.declared_storage_class = STORAGE_CLASS_EXTERN;
5933         entity->declaration.type                   = type;
5934         entity->declaration.implicit               = true;
5935
5936         if (current_scope != NULL)
5937                 record_entity(entity, false);
5938
5939         return entity;
5940 }
5941
5942 /**
5943  * Performs automatic type cast as described in §6.3.2.1.
5944  *
5945  * @param orig_type  the original type
5946  */
5947 static type_t *automatic_type_conversion(type_t *orig_type)
5948 {
5949         type_t *type = skip_typeref(orig_type);
5950         if (is_type_array(type)) {
5951                 array_type_t *array_type   = &type->array;
5952                 type_t       *element_type = array_type->element_type;
5953                 unsigned      qualifiers   = array_type->base.qualifiers;
5954
5955                 return make_pointer_type(element_type, qualifiers);
5956         }
5957
5958         if (is_type_function(type)) {
5959                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
5960         }
5961
5962         return orig_type;
5963 }
5964
5965 /**
5966  * reverts the automatic casts of array to pointer types and function
5967  * to function-pointer types as defined §6.3.2.1
5968  */
5969 type_t *revert_automatic_type_conversion(const expression_t *expression)
5970 {
5971         switch (expression->kind) {
5972         case EXPR_REFERENCE: {
5973                 entity_t *entity = expression->reference.entity;
5974                 if (is_declaration(entity)) {
5975                         return entity->declaration.type;
5976                 } else if (entity->kind == ENTITY_ENUM_VALUE) {
5977                         return entity->enum_value.enum_type;
5978                 } else {
5979                         panic("no declaration or enum in reference");
5980                 }
5981         }
5982
5983         case EXPR_SELECT: {
5984                 entity_t *entity = expression->select.compound_entry;
5985                 assert(is_declaration(entity));
5986                 type_t   *type   = entity->declaration.type;
5987                 return get_qualified_type(type, expression->base.type->base.qualifiers);
5988         }
5989
5990         case EXPR_UNARY_DEREFERENCE: {
5991                 const expression_t *const value = expression->unary.value;
5992                 type_t             *const type  = skip_typeref(value->base.type);
5993                 if (!is_type_pointer(type))
5994                         return type_error_type;
5995                 return type->pointer.points_to;
5996         }
5997
5998         case EXPR_ARRAY_ACCESS: {
5999                 const expression_t *array_ref = expression->array_access.array_ref;
6000                 type_t             *type_left = skip_typeref(array_ref->base.type);
6001                 if (!is_type_pointer(type_left))
6002                         return type_error_type;
6003                 return type_left->pointer.points_to;
6004         }
6005
6006         case EXPR_STRING_LITERAL: {
6007                 size_t  const size = get_string_len(&expression->string_literal.value) + 1;
6008                 type_t *const elem = get_unqualified_type(expression->base.type->pointer.points_to);
6009                 return make_array_type(elem, size, TYPE_QUALIFIER_NONE);
6010         }
6011
6012         case EXPR_COMPOUND_LITERAL:
6013                 return expression->compound_literal.type;
6014
6015         default:
6016                 break;
6017         }
6018         return expression->base.type;
6019 }
6020
6021 /**
6022  * Find an entity matching a symbol in a scope.
6023  * Uses current scope if scope is NULL
6024  */
6025 static entity_t *lookup_entity(const scope_t *scope, symbol_t *symbol,
6026                                namespace_tag_t namespc)
6027 {
6028         if (scope == NULL) {
6029                 return get_entity(symbol, namespc);
6030         }
6031
6032         /* we should optimize here, if scope grows above a certain size we should
6033            construct a hashmap here... */
6034         entity_t *entity = scope->entities;
6035         for ( ; entity != NULL; entity = entity->base.next) {
6036                 if (entity->base.symbol == symbol
6037                     && (namespace_tag_t)entity->base.namespc == namespc)
6038                         break;
6039         }
6040
6041         return entity;
6042 }
6043
6044 static entity_t *parse_qualified_identifier(void)
6045 {
6046         /* namespace containing the symbol */
6047         symbol_t          *symbol;
6048         source_position_t  pos;
6049         const scope_t     *lookup_scope = NULL;
6050
6051         if (accept(T_COLONCOLON))
6052                 lookup_scope = &unit->scope;
6053
6054         entity_t *entity;
6055         while (true) {
6056                 symbol = expect_identifier("while parsing identifier", &pos);
6057                 if (!symbol)
6058                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6059
6060                 /* lookup entity */
6061                 entity = lookup_entity(lookup_scope, symbol, NAMESPACE_NORMAL);
6062
6063                 if (!accept(T_COLONCOLON))
6064                         break;
6065
6066                 switch (entity->kind) {
6067                 case ENTITY_NAMESPACE:
6068                         lookup_scope = &entity->namespacee.members;
6069                         break;
6070                 case ENTITY_STRUCT:
6071                 case ENTITY_UNION:
6072                 case ENTITY_CLASS:
6073                         lookup_scope = &entity->compound.members;
6074                         break;
6075                 default:
6076                         errorf(&pos, "'%Y' must be a namespace, class, struct or union (but is a %s)",
6077                                symbol, get_entity_kind_name(entity->kind));
6078
6079                         /* skip further qualifications */
6080                         while (accept(T_IDENTIFIER) && accept(T_COLONCOLON)) {}
6081
6082                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6083                 }
6084         }
6085
6086         if (entity == NULL) {
6087                 if (!strict_mode && token.kind == '(') {
6088                         /* an implicitly declared function */
6089                         entity = create_implicit_function(symbol, &pos);
6090                         warningf(WARN_IMPLICIT_FUNCTION_DECLARATION, &pos, "implicit declaration of '%N'", entity);
6091                 } else {
6092                         errorf(&pos, "unknown identifier '%Y' found.", symbol);
6093                         entity = create_error_entity(symbol, ENTITY_VARIABLE);
6094                 }
6095         }
6096
6097         return entity;
6098 }
6099
6100 static expression_t *parse_reference(void)
6101 {
6102         source_position_t const pos    = *HERE;
6103         entity_t         *const entity = parse_qualified_identifier();
6104
6105         type_t *orig_type;
6106         if (is_declaration(entity)) {
6107                 orig_type = entity->declaration.type;
6108         } else if (entity->kind == ENTITY_ENUM_VALUE) {
6109                 orig_type = entity->enum_value.enum_type;
6110         } else {
6111                 panic("expected declaration or enum value in reference");
6112         }
6113
6114         /* we always do the auto-type conversions; the & and sizeof parser contains
6115          * code to revert this! */
6116         type_t *type = automatic_type_conversion(orig_type);
6117
6118         expression_kind_t kind = EXPR_REFERENCE;
6119         if (entity->kind == ENTITY_ENUM_VALUE)
6120                 kind = EXPR_ENUM_CONSTANT;
6121
6122         expression_t *expression         = allocate_expression_zero(kind);
6123         expression->base.source_position = pos;
6124         expression->base.type            = type;
6125         expression->reference.entity     = entity;
6126
6127         /* this declaration is used */
6128         if (is_declaration(entity)) {
6129                 entity->declaration.used = true;
6130         }
6131
6132         if (entity->base.parent_scope != file_scope
6133                 && (current_function != NULL
6134                         && entity->base.parent_scope->depth < current_function->parameters.depth)
6135                 && (entity->kind == ENTITY_VARIABLE || entity->kind == ENTITY_PARAMETER)) {
6136                 /* access of a variable from an outer function */
6137                 entity->variable.address_taken = true;
6138                 current_function->need_closure = true;
6139         }
6140
6141         check_deprecated(&pos, entity);
6142
6143         return expression;
6144 }
6145
6146 static bool semantic_cast(expression_t *cast)
6147 {
6148         expression_t            *expression      = cast->unary.value;
6149         type_t                  *orig_dest_type  = cast->base.type;
6150         type_t                  *orig_type_right = expression->base.type;
6151         type_t            const *dst_type        = skip_typeref(orig_dest_type);
6152         type_t            const *src_type        = skip_typeref(orig_type_right);
6153         source_position_t const *pos             = &cast->base.source_position;
6154
6155         /* §6.5.4 A (void) cast is explicitly permitted, more for documentation than for utility. */
6156         if (is_type_void(dst_type))
6157                 return true;
6158
6159         /* only integer and pointer can be casted to pointer */
6160         if (is_type_pointer(dst_type)  &&
6161             !is_type_pointer(src_type) &&
6162             !is_type_integer(src_type) &&
6163             is_type_valid(src_type)) {
6164                 errorf(pos, "cannot convert type '%T' to a pointer type", orig_type_right);
6165                 return false;
6166         }
6167
6168         if (!is_type_scalar(dst_type) && is_type_valid(dst_type)) {
6169                 errorf(pos, "conversion to non-scalar type '%T' requested", orig_dest_type);
6170                 return false;
6171         }
6172
6173         if (!is_type_scalar(src_type) && is_type_valid(src_type)) {
6174                 errorf(pos, "conversion from non-scalar type '%T' requested", orig_type_right);
6175                 return false;
6176         }
6177
6178         if (is_type_pointer(src_type) && is_type_pointer(dst_type)) {
6179                 type_t *src = skip_typeref(src_type->pointer.points_to);
6180                 type_t *dst = skip_typeref(dst_type->pointer.points_to);
6181                 unsigned missing_qualifiers =
6182                         src->base.qualifiers & ~dst->base.qualifiers;
6183                 if (missing_qualifiers != 0) {
6184                         warningf(WARN_CAST_QUAL, pos, "cast discards qualifiers '%Q' in pointer target type of '%T'", missing_qualifiers, orig_type_right);
6185                 }
6186         }
6187         return true;
6188 }
6189
6190 static expression_t *parse_compound_literal(source_position_t const *const pos,
6191                                             type_t *type)
6192 {
6193         expression_t *expression = allocate_expression_zero(EXPR_COMPOUND_LITERAL);
6194         expression->base.source_position = *pos;
6195         bool global_scope = current_scope == file_scope;
6196
6197         parse_initializer_env_t env;
6198         env.type             = type;
6199         env.entity           = NULL;
6200         env.must_be_constant = global_scope;
6201         initializer_t *initializer = parse_initializer(&env);
6202         type = env.type;
6203
6204         expression->base.type                     = automatic_type_conversion(type);
6205         expression->compound_literal.initializer  = initializer;
6206         expression->compound_literal.type         = type;
6207         expression->compound_literal.global_scope = global_scope;
6208
6209         return expression;
6210 }
6211
6212 /**
6213  * Parse a cast expression.
6214  */
6215 static expression_t *parse_cast(void)
6216 {
6217         source_position_t const pos = *HERE;
6218
6219         eat('(');
6220         add_anchor_token(')');
6221
6222         type_t *type = parse_typename();
6223
6224         rem_anchor_token(')');
6225         expect(')');
6226
6227         if (token.kind == '{') {
6228                 return parse_compound_literal(&pos, type);
6229         }
6230
6231         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
6232         cast->base.source_position = pos;
6233
6234         expression_t *value = parse_subexpression(PREC_CAST);
6235         cast->base.type   = type;
6236         cast->unary.value = value;
6237
6238         if (! semantic_cast(cast)) {
6239                 /* TODO: record the error in the AST. else it is impossible to detect it */
6240         }
6241
6242         return cast;
6243 }
6244
6245 /**
6246  * Parse a statement expression.
6247  */
6248 static expression_t *parse_statement_expression(void)
6249 {
6250         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
6251
6252         eat('(');
6253         add_anchor_token(')');
6254
6255         statement_t *statement          = parse_compound_statement(true);
6256         statement->compound.stmt_expr   = true;
6257         expression->statement.statement = statement;
6258
6259         /* find last statement and use its type */
6260         type_t *type = type_void;
6261         const statement_t *stmt = statement->compound.statements;
6262         if (stmt != NULL) {
6263                 while (stmt->base.next != NULL)
6264                         stmt = stmt->base.next;
6265
6266                 if (stmt->kind == STATEMENT_EXPRESSION) {
6267                         type = stmt->expression.expression->base.type;
6268                 }
6269         } else {
6270                 source_position_t const *const pos = &expression->base.source_position;
6271                 warningf(WARN_OTHER, pos, "empty statement expression ({})");
6272         }
6273         expression->base.type = type;
6274
6275         rem_anchor_token(')');
6276         expect(')');
6277         return expression;
6278 }
6279
6280 /**
6281  * Parse a parenthesized expression.
6282  */
6283 static expression_t *parse_parenthesized_expression(void)
6284 {
6285         token_t const* const la1 = look_ahead(1);
6286         switch (la1->kind) {
6287         case '{':
6288                 /* gcc extension: a statement expression */
6289                 return parse_statement_expression();
6290
6291         case T_IDENTIFIER:
6292                 if (is_typedef_symbol(la1->base.symbol)) {
6293         DECLARATION_START
6294                         return parse_cast();
6295                 }
6296         }
6297
6298         eat('(');
6299         add_anchor_token(')');
6300         expression_t *result = parse_expression();
6301         result->base.parenthesized = true;
6302         rem_anchor_token(')');
6303         expect(')');
6304
6305         return result;
6306 }
6307
6308 static expression_t *parse_function_keyword(funcname_kind_t const kind)
6309 {
6310         if (current_function == NULL) {
6311                 errorf(HERE, "%K used outside of a function", &token);
6312         }
6313
6314         expression_t *expression  = allocate_expression_zero(EXPR_FUNCNAME);
6315         expression->base.type     = type_char_ptr;
6316         expression->funcname.kind = kind;
6317
6318         next_token();
6319
6320         return expression;
6321 }
6322
6323 static designator_t *parse_designator(void)
6324 {
6325         designator_t *const result = allocate_ast_zero(sizeof(result[0]));
6326         result->symbol = expect_identifier("while parsing member designator", &result->source_position);
6327         if (!result->symbol)
6328                 return NULL;
6329
6330         designator_t *last_designator = result;
6331         while (true) {
6332                 if (accept('.')) {
6333                         designator_t *const designator = allocate_ast_zero(sizeof(result[0]));
6334                         designator->symbol = expect_identifier("while parsing member designator", &designator->source_position);
6335                         if (!designator->symbol)
6336                                 return NULL;
6337
6338                         last_designator->next = designator;
6339                         last_designator       = designator;
6340                         continue;
6341                 }
6342                 if (accept('[')) {
6343                         add_anchor_token(']');
6344                         designator_t *designator    = allocate_ast_zero(sizeof(result[0]));
6345                         designator->source_position = *HERE;
6346                         designator->array_index     = parse_expression();
6347                         rem_anchor_token(']');
6348                         expect(']');
6349                         if (designator->array_index == NULL) {
6350                                 return NULL;
6351                         }
6352
6353                         last_designator->next = designator;
6354                         last_designator       = designator;
6355                         continue;
6356                 }
6357                 break;
6358         }
6359
6360         return result;
6361 }
6362
6363 /**
6364  * Parse the __builtin_offsetof() expression.
6365  */
6366 static expression_t *parse_offsetof(void)
6367 {
6368         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
6369         expression->base.type    = type_size_t;
6370
6371         eat(T___builtin_offsetof);
6372
6373         add_anchor_token(')');
6374         add_anchor_token(',');
6375         expect('(');
6376         type_t *type = parse_typename();
6377         rem_anchor_token(',');
6378         expect(',');
6379         designator_t *designator = parse_designator();
6380         rem_anchor_token(')');
6381         expect(')');
6382
6383         expression->offsetofe.type       = type;
6384         expression->offsetofe.designator = designator;
6385
6386         type_path_t path;
6387         memset(&path, 0, sizeof(path));
6388         path.top_type = type;
6389         path.path     = NEW_ARR_F(type_path_entry_t, 0);
6390
6391         descend_into_subtype(&path);
6392
6393         if (!walk_designator(&path, designator, true)) {
6394                 return create_error_expression();
6395         }
6396
6397         DEL_ARR_F(path.path);
6398
6399         return expression;
6400 }
6401
6402 static bool is_last_parameter(expression_t *const param)
6403 {
6404         if (param->kind == EXPR_REFERENCE) {
6405                 entity_t *const entity = param->reference.entity;
6406                 if (entity->kind == ENTITY_PARAMETER &&
6407                     !entity->base.next               &&
6408                     entity->base.parent_scope == &current_function->parameters) {
6409                         return true;
6410                 }
6411         }
6412
6413         if (!is_type_valid(skip_typeref(param->base.type)))
6414                 return true;
6415
6416         return false;
6417 }
6418
6419 /**
6420  * Parses a __builtin_va_start() expression.
6421  */
6422 static expression_t *parse_va_start(void)
6423 {
6424         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
6425
6426         eat(T___builtin_va_start);
6427
6428         add_anchor_token(')');
6429         add_anchor_token(',');
6430         expect('(');
6431         expression->va_starte.ap = parse_assignment_expression();
6432         rem_anchor_token(',');
6433         expect(',');
6434         expression_t *const param = parse_assignment_expression();
6435         expression->va_starte.parameter = param;
6436         rem_anchor_token(')');
6437         expect(')');
6438
6439         if (!current_function) {
6440                 errorf(&expression->base.source_position, "'va_start' used outside of function");
6441         } else if (!current_function->base.type->function.variadic) {
6442                 errorf(&expression->base.source_position, "'va_start' used in non-variadic function");
6443         } else if (!is_last_parameter(param)) {
6444                 errorf(&param->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
6445         }
6446
6447         return expression;
6448 }
6449
6450 /**
6451  * Parses a __builtin_va_arg() expression.
6452  */
6453 static expression_t *parse_va_arg(void)
6454 {
6455         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
6456
6457         eat(T___builtin_va_arg);
6458
6459         add_anchor_token(')');
6460         add_anchor_token(',');
6461         expect('(');
6462         call_argument_t ap;
6463         ap.expression = parse_assignment_expression();
6464         expression->va_arge.ap = ap.expression;
6465         check_call_argument(type_valist, &ap, 1);
6466
6467         rem_anchor_token(',');
6468         expect(',');
6469         expression->base.type = parse_typename();
6470         rem_anchor_token(')');
6471         expect(')');
6472
6473         return expression;
6474 }
6475
6476 /**
6477  * Parses a __builtin_va_copy() expression.
6478  */
6479 static expression_t *parse_va_copy(void)
6480 {
6481         expression_t *expression = allocate_expression_zero(EXPR_VA_COPY);
6482
6483         eat(T___builtin_va_copy);
6484
6485         add_anchor_token(')');
6486         add_anchor_token(',');
6487         expect('(');
6488         expression_t *dst = parse_assignment_expression();
6489         assign_error_t error = semantic_assign(type_valist, dst);
6490         report_assign_error(error, type_valist, dst, "call argument 1",
6491                             &dst->base.source_position);
6492         expression->va_copye.dst = dst;
6493
6494         rem_anchor_token(',');
6495         expect(',');
6496
6497         call_argument_t src;
6498         src.expression = parse_assignment_expression();
6499         check_call_argument(type_valist, &src, 2);
6500         expression->va_copye.src = src.expression;
6501         rem_anchor_token(')');
6502         expect(')');
6503
6504         return expression;
6505 }
6506
6507 /**
6508  * Parses a __builtin_constant_p() expression.
6509  */
6510 static expression_t *parse_builtin_constant(void)
6511 {
6512         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
6513
6514         eat(T___builtin_constant_p);
6515
6516         add_anchor_token(')');
6517         expect('(');
6518         expression->builtin_constant.value = parse_assignment_expression();
6519         rem_anchor_token(')');
6520         expect(')');
6521         expression->base.type = type_int;
6522
6523         return expression;
6524 }
6525
6526 /**
6527  * Parses a __builtin_types_compatible_p() expression.
6528  */
6529 static expression_t *parse_builtin_types_compatible(void)
6530 {
6531         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_TYPES_COMPATIBLE_P);
6532
6533         eat(T___builtin_types_compatible_p);
6534
6535         add_anchor_token(')');
6536         add_anchor_token(',');
6537         expect('(');
6538         expression->builtin_types_compatible.left = parse_typename();
6539         rem_anchor_token(',');
6540         expect(',');
6541         expression->builtin_types_compatible.right = parse_typename();
6542         rem_anchor_token(')');
6543         expect(')');
6544         expression->base.type = type_int;
6545
6546         return expression;
6547 }
6548
6549 /**
6550  * Parses a __builtin_is_*() compare expression.
6551  */
6552 static expression_t *parse_compare_builtin(void)
6553 {
6554         expression_kind_t kind;
6555         switch (token.kind) {
6556         case T___builtin_isgreater:      kind = EXPR_BINARY_ISGREATER;      break;
6557         case T___builtin_isgreaterequal: kind = EXPR_BINARY_ISGREATEREQUAL; break;
6558         case T___builtin_isless:         kind = EXPR_BINARY_ISLESS;         break;
6559         case T___builtin_islessequal:    kind = EXPR_BINARY_ISLESSEQUAL;    break;
6560         case T___builtin_islessgreater:  kind = EXPR_BINARY_ISLESSGREATER;  break;
6561         case T___builtin_isunordered:    kind = EXPR_BINARY_ISUNORDERED;    break;
6562         default: internal_errorf(HERE, "invalid compare builtin found");
6563         }
6564         expression_t *const expression = allocate_expression_zero(kind);
6565         next_token();
6566
6567         add_anchor_token(')');
6568         add_anchor_token(',');
6569         expect('(');
6570         expression->binary.left = parse_assignment_expression();
6571         rem_anchor_token(',');
6572         expect(',');
6573         expression->binary.right = parse_assignment_expression();
6574         rem_anchor_token(')');
6575         expect(')');
6576
6577         type_t *const orig_type_left  = expression->binary.left->base.type;
6578         type_t *const orig_type_right = expression->binary.right->base.type;
6579
6580         type_t *const type_left  = skip_typeref(orig_type_left);
6581         type_t *const type_right = skip_typeref(orig_type_right);
6582         if (!is_type_float(type_left) && !is_type_float(type_right)) {
6583                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
6584                         type_error_incompatible("invalid operands in comparison",
6585                                 &expression->base.source_position, orig_type_left, orig_type_right);
6586                 }
6587         } else {
6588                 semantic_comparison(&expression->binary);
6589         }
6590
6591         return expression;
6592 }
6593
6594 /**
6595  * Parses a MS assume() expression.
6596  */
6597 static expression_t *parse_assume(void)
6598 {
6599         expression_t *expression = allocate_expression_zero(EXPR_UNARY_ASSUME);
6600
6601         eat(T__assume);
6602
6603         add_anchor_token(')');
6604         expect('(');
6605         expression->unary.value = parse_assignment_expression();
6606         rem_anchor_token(')');
6607         expect(')');
6608
6609         expression->base.type = type_void;
6610         return expression;
6611 }
6612
6613 /**
6614  * Return the label for the current symbol or create a new one.
6615  */
6616 static label_t *get_label(char const *const context)
6617 {
6618         assert(current_function != NULL);
6619
6620         symbol_t *const sym = expect_identifier(context, NULL);
6621         if (!sym)
6622                 return NULL;
6623
6624         entity_t *label = get_entity(sym, NAMESPACE_LABEL);
6625         /* If we find a local label, we already created the declaration. */
6626         if (label != NULL && label->kind == ENTITY_LOCAL_LABEL) {
6627                 if (label->base.parent_scope != current_scope) {
6628                         assert(label->base.parent_scope->depth < current_scope->depth);
6629                         current_function->goto_to_outer = true;
6630                 }
6631         } else if (label == NULL || label->base.parent_scope != &current_function->parameters) {
6632                 /* There is no matching label in the same function, so create a new one. */
6633                 source_position_t const nowhere = { NULL, 0, 0, false };
6634                 label = allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym, &nowhere);
6635                 label_push(label);
6636         }
6637
6638         return &label->label;
6639 }
6640
6641 /**
6642  * Parses a GNU && label address expression.
6643  */
6644 static expression_t *parse_label_address(void)
6645 {
6646         source_position_t const source_position = *HERE;
6647         eat(T_ANDAND);
6648
6649         label_t *const label = get_label("while parsing label address");
6650         if (!label)
6651                 return create_error_expression();
6652
6653         label->used          = true;
6654         label->address_taken = true;
6655
6656         expression_t *expression = allocate_expression_zero(EXPR_LABEL_ADDRESS);
6657         expression->base.source_position = source_position;
6658
6659         /* label address is treated as a void pointer */
6660         expression->base.type           = type_void_ptr;
6661         expression->label_address.label = label;
6662         return expression;
6663 }
6664
6665 /**
6666  * Parse a microsoft __noop expression.
6667  */
6668 static expression_t *parse_noop_expression(void)
6669 {
6670         /* the result is a (int)0 */
6671         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_MS_NOOP);
6672         literal->base.type           = type_int;
6673         literal->literal.value.begin = "__noop";
6674         literal->literal.value.size  = 6;
6675
6676         eat(T___noop);
6677
6678         if (token.kind == '(') {
6679                 /* parse arguments */
6680                 eat('(');
6681                 add_anchor_token(')');
6682                 add_anchor_token(',');
6683
6684                 if (token.kind != ')') do {
6685                         (void)parse_assignment_expression();
6686                 } while (accept(','));
6687
6688                 rem_anchor_token(',');
6689                 rem_anchor_token(')');
6690         }
6691         expect(')');
6692
6693         return literal;
6694 }
6695
6696 /**
6697  * Parses a primary expression.
6698  */
6699 static expression_t *parse_primary_expression(void)
6700 {
6701         switch (token.kind) {
6702         case T_false:                        return parse_boolean_literal(false);
6703         case T_true:                         return parse_boolean_literal(true);
6704         case T_NUMBER:                       return parse_number_literal();
6705         case T_CHARACTER_CONSTANT:           return parse_character_constant();
6706         case T_STRING_LITERAL:               return parse_string_literal();
6707         case T___func__:                     return parse_function_keyword(FUNCNAME_FUNCTION);
6708         case T___PRETTY_FUNCTION__:          return parse_function_keyword(FUNCNAME_PRETTY_FUNCTION);
6709         case T___FUNCSIG__:                  return parse_function_keyword(FUNCNAME_FUNCSIG);
6710         case T___FUNCDNAME__:                return parse_function_keyword(FUNCNAME_FUNCDNAME);
6711         case T___builtin_offsetof:           return parse_offsetof();
6712         case T___builtin_va_start:           return parse_va_start();
6713         case T___builtin_va_arg:             return parse_va_arg();
6714         case T___builtin_va_copy:            return parse_va_copy();
6715         case T___builtin_isgreater:
6716         case T___builtin_isgreaterequal:
6717         case T___builtin_isless:
6718         case T___builtin_islessequal:
6719         case T___builtin_islessgreater:
6720         case T___builtin_isunordered:        return parse_compare_builtin();
6721         case T___builtin_constant_p:         return parse_builtin_constant();
6722         case T___builtin_types_compatible_p: return parse_builtin_types_compatible();
6723         case T__assume:                      return parse_assume();
6724         case T_ANDAND:
6725                 if (GNU_MODE)
6726                         return parse_label_address();
6727                 break;
6728
6729         case '(':                            return parse_parenthesized_expression();
6730         case T___noop:                       return parse_noop_expression();
6731
6732         /* Gracefully handle type names while parsing expressions. */
6733         case T_COLONCOLON:
6734                 return parse_reference();
6735         case T_IDENTIFIER:
6736                 if (!is_typedef_symbol(token.base.symbol)) {
6737                         return parse_reference();
6738                 }
6739                 /* FALLTHROUGH */
6740         DECLARATION_START {
6741                 source_position_t const  pos = *HERE;
6742                 declaration_specifiers_t specifiers;
6743                 parse_declaration_specifiers(&specifiers);
6744                 type_t const *const type = parse_abstract_declarator(specifiers.type);
6745                 errorf(&pos, "encountered type '%T' while parsing expression", type);
6746                 return create_error_expression();
6747         }
6748         }
6749
6750         errorf(HERE, "unexpected token %K, expected an expression", &token);
6751         eat_until_anchor();
6752         return create_error_expression();
6753 }
6754
6755 static expression_t *parse_array_expression(expression_t *left)
6756 {
6757         expression_t              *const expr = allocate_expression_zero(EXPR_ARRAY_ACCESS);
6758         array_access_expression_t *const arr  = &expr->array_access;
6759
6760         eat('[');
6761         add_anchor_token(']');
6762
6763         expression_t *const inside = parse_expression();
6764
6765         type_t *const orig_type_left   = left->base.type;
6766         type_t *const orig_type_inside = inside->base.type;
6767
6768         type_t *const type_left   = skip_typeref(orig_type_left);
6769         type_t *const type_inside = skip_typeref(orig_type_inside);
6770
6771         expression_t *ref;
6772         expression_t *idx;
6773         type_t       *idx_type;
6774         type_t       *res_type;
6775         if (is_type_pointer(type_left)) {
6776                 ref      = left;
6777                 idx      = inside;
6778                 idx_type = type_inside;
6779                 res_type = type_left->pointer.points_to;
6780                 goto check_idx;
6781         } else if (is_type_pointer(type_inside)) {
6782                 arr->flipped = true;
6783                 ref      = inside;
6784                 idx      = left;
6785                 idx_type = type_left;
6786                 res_type = type_inside->pointer.points_to;
6787 check_idx:
6788                 res_type = automatic_type_conversion(res_type);
6789                 if (!is_type_integer(idx_type)) {
6790                         if (is_type_valid(idx_type))
6791                                 errorf(&idx->base.source_position, "array subscript must have integer type");
6792                 } else if (is_type_atomic(idx_type, ATOMIC_TYPE_CHAR)) {
6793                         source_position_t const *const pos = &idx->base.source_position;
6794                         warningf(WARN_CHAR_SUBSCRIPTS, pos, "array subscript has char type");
6795                 }
6796         } else {
6797                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
6798                         errorf(&expr->base.source_position, "invalid types '%T[%T]' for array access", orig_type_left, orig_type_inside);
6799                 }
6800                 res_type = type_error_type;
6801                 ref      = left;
6802                 idx      = inside;
6803         }
6804
6805         arr->array_ref = ref;
6806         arr->index     = idx;
6807         arr->base.type = res_type;
6808
6809         rem_anchor_token(']');
6810         expect(']');
6811         return expr;
6812 }
6813
6814 static bool is_bitfield(const expression_t *expression)
6815 {
6816         return expression->kind == EXPR_SELECT
6817                 && expression->select.compound_entry->compound_member.bitfield;
6818 }
6819
6820 static expression_t *parse_typeprop(expression_kind_t const kind)
6821 {
6822         expression_t  *tp_expression = allocate_expression_zero(kind);
6823         tp_expression->base.type     = type_size_t;
6824
6825         eat(kind == EXPR_SIZEOF ? T_sizeof : T__Alignof);
6826
6827         type_t       *orig_type;
6828         expression_t *expression;
6829         if (token.kind == '(' && is_declaration_specifier(look_ahead(1))) {
6830                 source_position_t const pos = *HERE;
6831                 eat('(');
6832                 add_anchor_token(')');
6833                 orig_type = parse_typename();
6834                 rem_anchor_token(')');
6835                 expect(')');
6836
6837                 if (token.kind == '{') {
6838                         /* It was not sizeof(type) after all.  It is sizeof of an expression
6839                          * starting with a compound literal */
6840                         expression = parse_compound_literal(&pos, orig_type);
6841                         goto typeprop_expression;
6842                 }
6843         } else {
6844                 expression = parse_subexpression(PREC_UNARY);
6845
6846 typeprop_expression:
6847                 if (is_bitfield(expression)) {
6848                         char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6849                         errorf(&tp_expression->base.source_position,
6850                                    "operand of %s expression must not be a bitfield", what);
6851                 }
6852
6853                 tp_expression->typeprop.tp_expression = expression;
6854
6855                 orig_type = revert_automatic_type_conversion(expression);
6856                 expression->base.type = orig_type;
6857         }
6858
6859         tp_expression->typeprop.type   = orig_type;
6860         type_t const* const type       = skip_typeref(orig_type);
6861         char   const*       wrong_type = NULL;
6862         if (is_type_incomplete(type)) {
6863                 if (!is_type_void(type) || !GNU_MODE)
6864                         wrong_type = "incomplete";
6865         } else if (type->kind == TYPE_FUNCTION) {
6866                 if (GNU_MODE) {
6867                         /* function types are allowed (and return 1) */
6868                         source_position_t const *const pos  = &tp_expression->base.source_position;
6869                         char              const *const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6870                         warningf(WARN_OTHER, pos, "%s expression with function argument returns invalid result", what);
6871                 } else {
6872                         wrong_type = "function";
6873                 }
6874         }
6875
6876         if (wrong_type != NULL) {
6877                 char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6878                 errorf(&tp_expression->base.source_position,
6879                                 "operand of %s expression must not be of %s type '%T'",
6880                                 what, wrong_type, orig_type);
6881         }
6882
6883         return tp_expression;
6884 }
6885
6886 static expression_t *parse_sizeof(void)
6887 {
6888         return parse_typeprop(EXPR_SIZEOF);
6889 }
6890
6891 static expression_t *parse_alignof(void)
6892 {
6893         return parse_typeprop(EXPR_ALIGNOF);
6894 }
6895
6896 static expression_t *parse_select_expression(expression_t *addr)
6897 {
6898         assert(token.kind == '.' || token.kind == T_MINUSGREATER);
6899         bool select_left_arrow = (token.kind == T_MINUSGREATER);
6900         source_position_t const pos = *HERE;
6901         next_token();
6902
6903         symbol_t *const symbol = expect_identifier("while parsing select", NULL);
6904         if (!symbol)
6905                 return create_error_expression();
6906
6907         type_t *const orig_type = addr->base.type;
6908         type_t *const type      = skip_typeref(orig_type);
6909
6910         type_t *type_left;
6911         bool    saw_error = false;
6912         if (is_type_pointer(type)) {
6913                 if (!select_left_arrow) {
6914                         errorf(&pos,
6915                                "request for member '%Y' in something not a struct or union, but '%T'",
6916                                symbol, orig_type);
6917                         saw_error = true;
6918                 }
6919                 type_left = skip_typeref(type->pointer.points_to);
6920         } else {
6921                 if (select_left_arrow && is_type_valid(type)) {
6922                         errorf(&pos, "left hand side of '->' is not a pointer, but '%T'", orig_type);
6923                         saw_error = true;
6924                 }
6925                 type_left = type;
6926         }
6927
6928         if (!is_type_compound(type_left)) {
6929                 if (is_type_valid(type_left) && !saw_error) {
6930                         errorf(&pos,
6931                                "request for member '%Y' in something not a struct or union, but '%T'",
6932                                symbol, type_left);
6933                 }
6934                 return create_error_expression();
6935         }
6936
6937         compound_t *compound = type_left->compound.compound;
6938         if (!compound->complete) {
6939                 errorf(&pos, "request for member '%Y' in incomplete type '%T'",
6940                        symbol, type_left);
6941                 return create_error_expression();
6942         }
6943
6944         type_qualifiers_t  qualifiers = type_left->base.qualifiers;
6945         expression_t      *result     =
6946                 find_create_select(&pos, addr, qualifiers, compound, symbol);
6947
6948         if (result == NULL) {
6949                 errorf(&pos, "'%T' has no member named '%Y'", orig_type, symbol);
6950                 return create_error_expression();
6951         }
6952
6953         return result;
6954 }
6955
6956 static void check_call_argument(type_t          *expected_type,
6957                                 call_argument_t *argument, unsigned pos)
6958 {
6959         type_t         *expected_type_skip = skip_typeref(expected_type);
6960         assign_error_t  error              = ASSIGN_ERROR_INCOMPATIBLE;
6961         expression_t   *arg_expr           = argument->expression;
6962         type_t         *arg_type           = skip_typeref(arg_expr->base.type);
6963
6964         /* handle transparent union gnu extension */
6965         if (is_type_union(expected_type_skip)
6966                         && (get_type_modifiers(expected_type) & DM_TRANSPARENT_UNION)) {
6967                 compound_t *union_decl  = expected_type_skip->compound.compound;
6968                 type_t     *best_type   = NULL;
6969                 entity_t   *entry       = union_decl->members.entities;
6970                 for ( ; entry != NULL; entry = entry->base.next) {
6971                         assert(is_declaration(entry));
6972                         type_t *decl_type = entry->declaration.type;
6973                         error = semantic_assign(decl_type, arg_expr);
6974                         if (error == ASSIGN_ERROR_INCOMPATIBLE
6975                                 || error == ASSIGN_ERROR_POINTER_QUALIFIER_MISSING)
6976                                 continue;
6977
6978                         if (error == ASSIGN_SUCCESS) {
6979                                 best_type = decl_type;
6980                         } else if (best_type == NULL) {
6981                                 best_type = decl_type;
6982                         }
6983                 }
6984
6985                 if (best_type != NULL) {
6986                         expected_type = best_type;
6987                 }
6988         }
6989
6990         error                = semantic_assign(expected_type, arg_expr);
6991         argument->expression = create_implicit_cast(arg_expr, expected_type);
6992
6993         if (error != ASSIGN_SUCCESS) {
6994                 /* report exact scope in error messages (like "in argument 3") */
6995                 char buf[64];
6996                 snprintf(buf, sizeof(buf), "call argument %u", pos);
6997                 report_assign_error(error, expected_type, arg_expr, buf,
6998                                     &arg_expr->base.source_position);
6999         } else {
7000                 type_t *const promoted_type = get_default_promoted_type(arg_type);
7001                 if (!types_compatible(expected_type_skip, promoted_type) &&
7002                     !types_compatible(expected_type_skip, type_void_ptr) &&
7003                     !types_compatible(type_void_ptr,      promoted_type)) {
7004                         /* Deliberately show the skipped types in this warning */
7005                         source_position_t const *const apos = &arg_expr->base.source_position;
7006                         warningf(WARN_TRADITIONAL, apos, "passing call argument %u as '%T' rather than '%T' due to prototype", pos, expected_type_skip, promoted_type);
7007                 }
7008         }
7009 }
7010
7011 /**
7012  * Handle the semantic restrictions of builtin calls
7013  */
7014 static void handle_builtin_argument_restrictions(call_expression_t *call)
7015 {
7016         entity_t *entity = call->function->reference.entity;
7017         switch (entity->function.btk) {
7018         case BUILTIN_FIRM:
7019                 switch (entity->function.b.firm_builtin_kind) {
7020                 case ir_bk_return_address:
7021                 case ir_bk_frame_address: {
7022                         /* argument must be constant */
7023                         call_argument_t *argument = call->arguments;
7024
7025                         if (is_constant_expression(argument->expression) == EXPR_CLASS_VARIABLE) {
7026                                 errorf(&call->base.source_position,
7027                                            "argument of '%Y' must be a constant expression",
7028                                            call->function->reference.entity->base.symbol);
7029                         }
7030                         break;
7031                 }
7032                 case ir_bk_prefetch:
7033                         /* second and third argument must be constant if existent */
7034                         if (call->arguments == NULL)
7035                                 break;
7036                         call_argument_t *rw = call->arguments->next;
7037                         call_argument_t *locality = NULL;
7038
7039                         if (rw != NULL) {
7040                                 if (is_constant_expression(rw->expression) == EXPR_CLASS_VARIABLE) {
7041                                         errorf(&call->base.source_position,
7042                                                    "second argument of '%Y' must be a constant expression",
7043                                                    call->function->reference.entity->base.symbol);
7044                                 }
7045                                 locality = rw->next;
7046                         }
7047                         if (locality != NULL) {
7048                                 if (is_constant_expression(locality->expression) == EXPR_CLASS_VARIABLE) {
7049                                         errorf(&call->base.source_position,
7050                                                    "third argument of '%Y' must be a constant expression",
7051                                                    call->function->reference.entity->base.symbol);
7052                                 }
7053                         }
7054                         break;
7055                 default:
7056                         break;
7057                 }
7058
7059         case BUILTIN_OBJECT_SIZE:
7060                 if (call->arguments == NULL)
7061                         break;
7062
7063                 call_argument_t *arg = call->arguments->next;
7064                 if (arg != NULL && is_constant_expression(arg->expression) == EXPR_CLASS_VARIABLE) {
7065                         errorf(&call->base.source_position,
7066                                    "second argument of '%Y' must be a constant expression",
7067                                    call->function->reference.entity->base.symbol);
7068                 }
7069                 break;
7070         default:
7071                 break;
7072         }
7073 }
7074
7075 /**
7076  * Parse a call expression, ie. expression '( ... )'.
7077  *
7078  * @param expression  the function address
7079  */
7080 static expression_t *parse_call_expression(expression_t *expression)
7081 {
7082         expression_t      *result = allocate_expression_zero(EXPR_CALL);
7083         call_expression_t *call   = &result->call;
7084         call->function            = expression;
7085
7086         type_t *const orig_type = expression->base.type;
7087         type_t *const type      = skip_typeref(orig_type);
7088
7089         function_type_t *function_type = NULL;
7090         if (is_type_pointer(type)) {
7091                 type_t *const to_type = skip_typeref(type->pointer.points_to);
7092
7093                 if (is_type_function(to_type)) {
7094                         function_type   = &to_type->function;
7095                         call->base.type = function_type->return_type;
7096                 }
7097         }
7098
7099         if (function_type == NULL && is_type_valid(type)) {
7100                 errorf(HERE,
7101                        "called object '%E' (type '%T') is not a pointer to a function",
7102                        expression, orig_type);
7103         }
7104
7105         /* parse arguments */
7106         eat('(');
7107         add_anchor_token(')');
7108         add_anchor_token(',');
7109
7110         if (token.kind != ')') {
7111                 call_argument_t **anchor = &call->arguments;
7112                 do {
7113                         call_argument_t *argument = allocate_ast_zero(sizeof(*argument));
7114                         argument->expression = parse_assignment_expression();
7115
7116                         *anchor = argument;
7117                         anchor  = &argument->next;
7118                 } while (accept(','));
7119         }
7120         rem_anchor_token(',');
7121         rem_anchor_token(')');
7122         expect(')');
7123
7124         if (function_type == NULL)
7125                 return result;
7126
7127         /* check type and count of call arguments */
7128         function_parameter_t *parameter = function_type->parameters;
7129         call_argument_t      *argument  = call->arguments;
7130         if (!function_type->unspecified_parameters) {
7131                 for (unsigned pos = 0; parameter != NULL && argument != NULL;
7132                                 parameter = parameter->next, argument = argument->next) {
7133                         check_call_argument(parameter->type, argument, ++pos);
7134                 }
7135
7136                 if (parameter != NULL) {
7137                         errorf(&expression->base.source_position, "too few arguments to function '%E'", expression);
7138                 } else if (argument != NULL && !function_type->variadic) {
7139                         errorf(&argument->expression->base.source_position, "too many arguments to function '%E'", expression);
7140                 }
7141         }
7142
7143         /* do default promotion for other arguments */
7144         for (; argument != NULL; argument = argument->next) {
7145                 type_t *argument_type = argument->expression->base.type;
7146                 if (!is_type_object(skip_typeref(argument_type))) {
7147                         errorf(&argument->expression->base.source_position,
7148                                "call argument '%E' must not be void", argument->expression);
7149                 }
7150
7151                 argument_type = get_default_promoted_type(argument_type);
7152
7153                 argument->expression
7154                         = create_implicit_cast(argument->expression, argument_type);
7155         }
7156
7157         check_format(call);
7158
7159         if (is_type_compound(skip_typeref(function_type->return_type))) {
7160                 source_position_t const *const pos = &expression->base.source_position;
7161                 warningf(WARN_AGGREGATE_RETURN, pos, "function call has aggregate value");
7162         }
7163
7164         if (expression->kind == EXPR_REFERENCE) {
7165                 reference_expression_t *reference = &expression->reference;
7166                 if (reference->entity->kind == ENTITY_FUNCTION &&
7167                     reference->entity->function.btk != BUILTIN_NONE)
7168                         handle_builtin_argument_restrictions(call);
7169         }
7170
7171         return result;
7172 }
7173
7174 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
7175
7176 static bool same_compound_type(const type_t *type1, const type_t *type2)
7177 {
7178         return
7179                 is_type_compound(type1) &&
7180                 type1->kind == type2->kind &&
7181                 type1->compound.compound == type2->compound.compound;
7182 }
7183
7184 static expression_t const *get_reference_address(expression_t const *expr)
7185 {
7186         bool regular_take_address = true;
7187         for (;;) {
7188                 if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7189                         expr = expr->unary.value;
7190                 } else {
7191                         regular_take_address = false;
7192                 }
7193
7194                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7195                         break;
7196
7197                 expr = expr->unary.value;
7198         }
7199
7200         if (expr->kind != EXPR_REFERENCE)
7201                 return NULL;
7202
7203         /* special case for functions which are automatically converted to a
7204          * pointer to function without an extra TAKE_ADDRESS operation */
7205         if (!regular_take_address &&
7206                         expr->reference.entity->kind != ENTITY_FUNCTION) {
7207                 return NULL;
7208         }
7209
7210         return expr;
7211 }
7212
7213 static void warn_reference_address_as_bool(expression_t const* expr)
7214 {
7215         expr = get_reference_address(expr);
7216         if (expr != NULL) {
7217                 source_position_t const *const pos = &expr->base.source_position;
7218                 entity_t          const *const ent = expr->reference.entity;
7219                 warningf(WARN_ADDRESS, pos, "the address of '%N' will always evaluate as 'true'", ent);
7220         }
7221 }
7222
7223 static void warn_assignment_in_condition(const expression_t *const expr)
7224 {
7225         if (expr->base.kind != EXPR_BINARY_ASSIGN)
7226                 return;
7227         if (expr->base.parenthesized)
7228                 return;
7229         source_position_t const *const pos = &expr->base.source_position;
7230         warningf(WARN_PARENTHESES, pos, "suggest parentheses around assignment used as truth value");
7231 }
7232
7233 static void semantic_condition(expression_t const *const expr,
7234                                char const *const context)
7235 {
7236         type_t *const type = skip_typeref(expr->base.type);
7237         if (is_type_scalar(type)) {
7238                 warn_reference_address_as_bool(expr);
7239                 warn_assignment_in_condition(expr);
7240         } else if (is_type_valid(type)) {
7241                 errorf(&expr->base.source_position,
7242                                 "%s must have scalar type", context);
7243         }
7244 }
7245
7246 /**
7247  * Parse a conditional expression, ie. 'expression ? ... : ...'.
7248  *
7249  * @param expression  the conditional expression
7250  */
7251 static expression_t *parse_conditional_expression(expression_t *expression)
7252 {
7253         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
7254
7255         conditional_expression_t *conditional = &result->conditional;
7256         conditional->condition                = expression;
7257
7258         eat('?');
7259         add_anchor_token(':');
7260
7261         /* §6.5.15:2  The first operand shall have scalar type. */
7262         semantic_condition(expression, "condition of conditional operator");
7263
7264         expression_t *true_expression = expression;
7265         bool          gnu_cond = false;
7266         if (GNU_MODE && token.kind == ':') {
7267                 gnu_cond = true;
7268         } else {
7269                 true_expression = parse_expression();
7270         }
7271         rem_anchor_token(':');
7272         expect(':');
7273         expression_t *false_expression =
7274                 parse_subexpression(c_mode & _CXX ? PREC_ASSIGNMENT : PREC_CONDITIONAL);
7275
7276         type_t *const orig_true_type  = true_expression->base.type;
7277         type_t *const orig_false_type = false_expression->base.type;
7278         type_t *const true_type       = skip_typeref(orig_true_type);
7279         type_t *const false_type      = skip_typeref(orig_false_type);
7280
7281         /* 6.5.15.3 */
7282         source_position_t const *const pos = &conditional->base.source_position;
7283         type_t                        *result_type;
7284         if (is_type_void(true_type) || is_type_void(false_type)) {
7285                 /* ISO/IEC 14882:1998(E) §5.16:2 */
7286                 if (true_expression->kind == EXPR_UNARY_THROW) {
7287                         result_type = false_type;
7288                 } else if (false_expression->kind == EXPR_UNARY_THROW) {
7289                         result_type = true_type;
7290                 } else {
7291                         if (!is_type_void(true_type) || !is_type_void(false_type)) {
7292                                 warningf(WARN_OTHER, pos, "ISO C forbids conditional expression with only one void side");
7293                         }
7294                         result_type = type_void;
7295                 }
7296         } else if (is_type_arithmetic(true_type)
7297                    && is_type_arithmetic(false_type)) {
7298                 result_type = semantic_arithmetic(true_type, false_type);
7299         } else if (same_compound_type(true_type, false_type)) {
7300                 /* just take 1 of the 2 types */
7301                 result_type = true_type;
7302         } else if (is_type_pointer(true_type) || is_type_pointer(false_type)) {
7303                 type_t *pointer_type;
7304                 type_t *other_type;
7305                 expression_t *other_expression;
7306                 if (is_type_pointer(true_type) &&
7307                                 (!is_type_pointer(false_type) || is_null_pointer_constant(false_expression))) {
7308                         pointer_type     = true_type;
7309                         other_type       = false_type;
7310                         other_expression = false_expression;
7311                 } else {
7312                         pointer_type     = false_type;
7313                         other_type       = true_type;
7314                         other_expression = true_expression;
7315                 }
7316
7317                 if (is_null_pointer_constant(other_expression)) {
7318                         result_type = pointer_type;
7319                 } else if (is_type_pointer(other_type)) {
7320                         type_t *to1 = skip_typeref(pointer_type->pointer.points_to);
7321                         type_t *to2 = skip_typeref(other_type->pointer.points_to);
7322
7323                         type_t *to;
7324                         if (is_type_void(to1) || is_type_void(to2)) {
7325                                 to = type_void;
7326                         } else if (types_compatible(get_unqualified_type(to1),
7327                                                     get_unqualified_type(to2))) {
7328                                 to = to1;
7329                         } else {
7330                                 warningf(WARN_OTHER, pos, "pointer types '%T' and '%T' in conditional expression are incompatible", true_type, false_type);
7331                                 to = type_void;
7332                         }
7333
7334                         type_t *const type =
7335                                 get_qualified_type(to, to1->base.qualifiers | to2->base.qualifiers);
7336                         result_type = make_pointer_type(type, TYPE_QUALIFIER_NONE);
7337                 } else if (is_type_integer(other_type)) {
7338                         warningf(WARN_OTHER, pos, "pointer/integer type mismatch in conditional expression ('%T' and '%T')", true_type, false_type);
7339                         result_type = pointer_type;
7340                 } else {
7341                         goto types_incompatible;
7342                 }
7343         } else {
7344 types_incompatible:
7345                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
7346                         type_error_incompatible("while parsing conditional", pos, true_type, false_type);
7347                 }
7348                 result_type = type_error_type;
7349         }
7350
7351         conditional->true_expression
7352                 = gnu_cond ? NULL : create_implicit_cast(true_expression, result_type);
7353         conditional->false_expression
7354                 = create_implicit_cast(false_expression, result_type);
7355         conditional->base.type = result_type;
7356         return result;
7357 }
7358
7359 /**
7360  * Parse an extension expression.
7361  */
7362 static expression_t *parse_extension(void)
7363 {
7364         PUSH_EXTENSION();
7365         expression_t *expression = parse_subexpression(PREC_UNARY);
7366         POP_EXTENSION();
7367         return expression;
7368 }
7369
7370 /**
7371  * Parse a __builtin_classify_type() expression.
7372  */
7373 static expression_t *parse_builtin_classify_type(void)
7374 {
7375         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
7376         result->base.type    = type_int;
7377
7378         eat(T___builtin_classify_type);
7379
7380         add_anchor_token(')');
7381         expect('(');
7382         expression_t *expression = parse_expression();
7383         rem_anchor_token(')');
7384         expect(')');
7385         result->classify_type.type_expression = expression;
7386
7387         return result;
7388 }
7389
7390 /**
7391  * Parse a delete expression
7392  * ISO/IEC 14882:1998(E) §5.3.5
7393  */
7394 static expression_t *parse_delete(void)
7395 {
7396         expression_t *const result = allocate_expression_zero(EXPR_UNARY_DELETE);
7397         result->base.type          = type_void;
7398
7399         eat(T_delete);
7400
7401         if (accept('[')) {
7402                 result->kind = EXPR_UNARY_DELETE_ARRAY;
7403                 expect(']');
7404         }
7405
7406         expression_t *const value = parse_subexpression(PREC_CAST);
7407         result->unary.value = value;
7408
7409         type_t *const type = skip_typeref(value->base.type);
7410         if (!is_type_pointer(type)) {
7411                 if (is_type_valid(type)) {
7412                         errorf(&value->base.source_position,
7413                                         "operand of delete must have pointer type");
7414                 }
7415         } else if (is_type_void(skip_typeref(type->pointer.points_to))) {
7416                 source_position_t const *const pos = &value->base.source_position;
7417                 warningf(WARN_OTHER, pos, "deleting 'void*' is undefined");
7418         }
7419
7420         return result;
7421 }
7422
7423 /**
7424  * Parse a throw expression
7425  * ISO/IEC 14882:1998(E) §15:1
7426  */
7427 static expression_t *parse_throw(void)
7428 {
7429         expression_t *const result = allocate_expression_zero(EXPR_UNARY_THROW);
7430         result->base.type          = type_void;
7431
7432         eat(T_throw);
7433
7434         expression_t *value = NULL;
7435         switch (token.kind) {
7436                 EXPRESSION_START {
7437                         value = parse_assignment_expression();
7438                         /* ISO/IEC 14882:1998(E) §15.1:3 */
7439                         type_t *const orig_type = value->base.type;
7440                         type_t *const type      = skip_typeref(orig_type);
7441                         if (is_type_incomplete(type)) {
7442                                 errorf(&value->base.source_position,
7443                                                 "cannot throw object of incomplete type '%T'", orig_type);
7444                         } else if (is_type_pointer(type)) {
7445                                 type_t *const points_to = skip_typeref(type->pointer.points_to);
7446                                 if (is_type_incomplete(points_to) && !is_type_void(points_to)) {
7447                                         errorf(&value->base.source_position,
7448                                                         "cannot throw pointer to incomplete type '%T'", orig_type);
7449                                 }
7450                         }
7451                 }
7452
7453                 default:
7454                         break;
7455         }
7456         result->unary.value = value;
7457
7458         return result;
7459 }
7460
7461 static bool check_pointer_arithmetic(const source_position_t *source_position,
7462                                      type_t *pointer_type,
7463                                      type_t *orig_pointer_type)
7464 {
7465         type_t *points_to = pointer_type->pointer.points_to;
7466         points_to = skip_typeref(points_to);
7467
7468         if (is_type_incomplete(points_to)) {
7469                 if (!GNU_MODE || !is_type_void(points_to)) {
7470                         errorf(source_position,
7471                                "arithmetic with pointer to incomplete type '%T' not allowed",
7472                                orig_pointer_type);
7473                         return false;
7474                 } else {
7475                         warningf(WARN_POINTER_ARITH, source_position, "pointer of type '%T' used in arithmetic", orig_pointer_type);
7476                 }
7477         } else if (is_type_function(points_to)) {
7478                 if (!GNU_MODE) {
7479                         errorf(source_position,
7480                                "arithmetic with pointer to function type '%T' not allowed",
7481                                orig_pointer_type);
7482                         return false;
7483                 } else {
7484                         warningf(WARN_POINTER_ARITH, source_position, "pointer to a function '%T' used in arithmetic", orig_pointer_type);
7485                 }
7486         }
7487         return true;
7488 }
7489
7490 static bool is_lvalue(const expression_t *expression)
7491 {
7492         /* TODO: doesn't seem to be consistent with §6.3.2.1:1 */
7493         switch (expression->kind) {
7494         case EXPR_ARRAY_ACCESS:
7495         case EXPR_COMPOUND_LITERAL:
7496         case EXPR_REFERENCE:
7497         case EXPR_SELECT:
7498         case EXPR_UNARY_DEREFERENCE:
7499                 return true;
7500
7501         default: {
7502                 type_t *type = skip_typeref(expression->base.type);
7503                 return
7504                         /* ISO/IEC 14882:1998(E) §3.10:3 */
7505                         is_type_reference(type) ||
7506                         /* Claim it is an lvalue, if the type is invalid.  There was a parse
7507                          * error before, which maybe prevented properly recognizing it as
7508                          * lvalue. */
7509                         !is_type_valid(type);
7510         }
7511         }
7512 }
7513
7514 static void semantic_incdec(unary_expression_t *expression)
7515 {
7516         type_t *const orig_type = expression->value->base.type;
7517         type_t *const type      = skip_typeref(orig_type);
7518         if (is_type_pointer(type)) {
7519                 if (!check_pointer_arithmetic(&expression->base.source_position,
7520                                               type, orig_type)) {
7521                         return;
7522                 }
7523         } else if (!is_type_real(type) && is_type_valid(type)) {
7524                 /* TODO: improve error message */
7525                 errorf(&expression->base.source_position,
7526                        "operation needs an arithmetic or pointer type");
7527                 return;
7528         }
7529         if (!is_lvalue(expression->value)) {
7530                 /* TODO: improve error message */
7531                 errorf(&expression->base.source_position, "lvalue required as operand");
7532         }
7533         expression->base.type = orig_type;
7534 }
7535
7536 static void promote_unary_int_expr(unary_expression_t *const expr, type_t *const type)
7537 {
7538         type_t *const res_type = promote_integer(type);
7539         expr->base.type = res_type;
7540         expr->value     = create_implicit_cast(expr->value, res_type);
7541 }
7542
7543 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
7544 {
7545         type_t *const orig_type = expression->value->base.type;
7546         type_t *const type      = skip_typeref(orig_type);
7547         if (!is_type_arithmetic(type)) {
7548                 if (is_type_valid(type)) {
7549                         source_position_t const *const pos = &expression->base.source_position;
7550                         errorf(pos, "operand of unary expression must have arithmetic type, but is '%T'", orig_type);
7551                 }
7552                 return;
7553         } else if (is_type_integer(type)) {
7554                 promote_unary_int_expr(expression, type);
7555         } else {
7556                 expression->base.type = orig_type;
7557         }
7558 }
7559
7560 static void semantic_unexpr_plus(unary_expression_t *expression)
7561 {
7562         semantic_unexpr_arithmetic(expression);
7563         source_position_t const *const pos = &expression->base.source_position;
7564         warningf(WARN_TRADITIONAL, pos, "traditional C rejects the unary plus operator");
7565 }
7566
7567 static void semantic_not(unary_expression_t *expression)
7568 {
7569         /* §6.5.3.3:1  The operand [...] of the ! operator, scalar type. */
7570         semantic_condition(expression->value, "operand of !");
7571         expression->base.type = c_mode & _CXX ? type_bool : type_int;
7572 }
7573
7574 static void semantic_unexpr_integer(unary_expression_t *expression)
7575 {
7576         type_t *const orig_type = expression->value->base.type;
7577         type_t *const type      = skip_typeref(orig_type);
7578         if (!is_type_integer(type)) {
7579                 if (is_type_valid(type)) {
7580                         errorf(&expression->base.source_position,
7581                                "operand of ~ must be of integer type");
7582                 }
7583                 return;
7584         }
7585
7586         promote_unary_int_expr(expression, type);
7587 }
7588
7589 static void semantic_dereference(unary_expression_t *expression)
7590 {
7591         type_t *const orig_type = expression->value->base.type;
7592         type_t *const type      = skip_typeref(orig_type);
7593         if (!is_type_pointer(type)) {
7594                 if (is_type_valid(type)) {
7595                         errorf(&expression->base.source_position,
7596                                "Unary '*' needs pointer or array type, but type '%T' given", orig_type);
7597                 }
7598                 return;
7599         }
7600
7601         type_t *result_type   = type->pointer.points_to;
7602         result_type           = automatic_type_conversion(result_type);
7603         expression->base.type = result_type;
7604 }
7605
7606 /**
7607  * Record that an address is taken (expression represents an lvalue).
7608  *
7609  * @param expression       the expression
7610  * @param may_be_register  if true, the expression might be an register
7611  */
7612 static void set_address_taken(expression_t *expression, bool may_be_register)
7613 {
7614         if (expression->kind != EXPR_REFERENCE)
7615                 return;
7616
7617         entity_t *const entity = expression->reference.entity;
7618
7619         if (entity->kind != ENTITY_VARIABLE && entity->kind != ENTITY_PARAMETER)
7620                 return;
7621
7622         if (entity->declaration.storage_class == STORAGE_CLASS_REGISTER
7623                         && !may_be_register) {
7624                 source_position_t const *const pos = &expression->base.source_position;
7625                 errorf(pos, "address of register '%N' requested", entity);
7626         }
7627
7628         entity->variable.address_taken = true;
7629 }
7630
7631 /**
7632  * Check the semantic of the address taken expression.
7633  */
7634 static void semantic_take_addr(unary_expression_t *expression)
7635 {
7636         expression_t *value = expression->value;
7637         value->base.type    = revert_automatic_type_conversion(value);
7638
7639         type_t *orig_type = value->base.type;
7640         type_t *type      = skip_typeref(orig_type);
7641         if (!is_type_valid(type))
7642                 return;
7643
7644         /* §6.5.3.2 */
7645         if (!is_lvalue(value)) {
7646                 errorf(&expression->base.source_position, "'&' requires an lvalue");
7647         }
7648         if (is_bitfield(value)) {
7649                 errorf(&expression->base.source_position,
7650                        "'&' not allowed on bitfield");
7651         }
7652
7653         set_address_taken(value, false);
7654
7655         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
7656 }
7657
7658 #define CREATE_UNARY_EXPRESSION_PARSER(token_kind, unexpression_type, sfunc) \
7659 static expression_t *parse_##unexpression_type(void)                         \
7660 {                                                                            \
7661         expression_t *unary_expression                                           \
7662                 = allocate_expression_zero(unexpression_type);                       \
7663         eat(token_kind);                                                         \
7664         unary_expression->unary.value = parse_subexpression(PREC_UNARY);         \
7665                                                                                  \
7666         sfunc(&unary_expression->unary);                                         \
7667                                                                                  \
7668         return unary_expression;                                                 \
7669 }
7670
7671 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
7672                                semantic_unexpr_arithmetic)
7673 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
7674                                semantic_unexpr_plus)
7675 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
7676                                semantic_not)
7677 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
7678                                semantic_dereference)
7679 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
7680                                semantic_take_addr)
7681 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
7682                                semantic_unexpr_integer)
7683 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
7684                                semantic_incdec)
7685 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
7686                                semantic_incdec)
7687
7688 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_kind, unexpression_type, \
7689                                                sfunc)                         \
7690 static expression_t *parse_##unexpression_type(expression_t *left)            \
7691 {                                                                             \
7692         expression_t *unary_expression                                            \
7693                 = allocate_expression_zero(unexpression_type);                        \
7694         eat(token_kind);                                                          \
7695         unary_expression->unary.value = left;                                     \
7696                                                                                   \
7697         sfunc(&unary_expression->unary);                                          \
7698                                                                               \
7699         return unary_expression;                                                  \
7700 }
7701
7702 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
7703                                        EXPR_UNARY_POSTFIX_INCREMENT,
7704                                        semantic_incdec)
7705 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
7706                                        EXPR_UNARY_POSTFIX_DECREMENT,
7707                                        semantic_incdec)
7708
7709 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
7710 {
7711         /* TODO: handle complex + imaginary types */
7712
7713         type_left  = get_unqualified_type(type_left);
7714         type_right = get_unqualified_type(type_right);
7715
7716         /* §6.3.1.8 Usual arithmetic conversions */
7717         if (type_left == type_long_double || type_right == type_long_double) {
7718                 return type_long_double;
7719         } else if (type_left == type_double || type_right == type_double) {
7720                 return type_double;
7721         } else if (type_left == type_float || type_right == type_float) {
7722                 return type_float;
7723         }
7724
7725         type_left  = promote_integer(type_left);
7726         type_right = promote_integer(type_right);
7727
7728         if (type_left == type_right)
7729                 return type_left;
7730
7731         bool     const signed_left  = is_type_signed(type_left);
7732         bool     const signed_right = is_type_signed(type_right);
7733         unsigned const rank_left    = get_akind_rank(get_akind(type_left));
7734         unsigned const rank_right   = get_akind_rank(get_akind(type_right));
7735
7736         if (signed_left == signed_right)
7737                 return rank_left >= rank_right ? type_left : type_right;
7738
7739         unsigned           s_rank;
7740         unsigned           u_rank;
7741         atomic_type_kind_t s_akind;
7742         atomic_type_kind_t u_akind;
7743         type_t *s_type;
7744         type_t *u_type;
7745         if (signed_left) {
7746                 s_type = type_left;
7747                 u_type = type_right;
7748         } else {
7749                 s_type = type_right;
7750                 u_type = type_left;
7751         }
7752         s_akind = get_akind(s_type);
7753         u_akind = get_akind(u_type);
7754         s_rank  = get_akind_rank(s_akind);
7755         u_rank  = get_akind_rank(u_akind);
7756
7757         if (u_rank >= s_rank)
7758                 return u_type;
7759
7760         if (get_atomic_type_size(s_akind) > get_atomic_type_size(u_akind))
7761                 return s_type;
7762
7763         switch (s_akind) {
7764         case ATOMIC_TYPE_INT:      return type_unsigned_int;
7765         case ATOMIC_TYPE_LONG:     return type_unsigned_long;
7766         case ATOMIC_TYPE_LONGLONG: return type_unsigned_long_long;
7767
7768         default: panic("invalid atomic type");
7769         }
7770 }
7771
7772 /**
7773  * Check the semantic restrictions for a binary expression.
7774  */
7775 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
7776 {
7777         expression_t *const left            = expression->left;
7778         expression_t *const right           = expression->right;
7779         type_t       *const orig_type_left  = left->base.type;
7780         type_t       *const orig_type_right = right->base.type;
7781         type_t       *const type_left       = skip_typeref(orig_type_left);
7782         type_t       *const type_right      = skip_typeref(orig_type_right);
7783
7784         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
7785                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7786                         source_position_t const *const pos = &expression->base.source_position;
7787                         errorf(pos, "operands of binary expression must have arithmetic types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7788                 }
7789                 return;
7790         }
7791
7792         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7793         expression->left      = create_implicit_cast(left, arithmetic_type);
7794         expression->right     = create_implicit_cast(right, arithmetic_type);
7795         expression->base.type = arithmetic_type;
7796 }
7797
7798 static void semantic_binexpr_integer(binary_expression_t *const expression)
7799 {
7800         expression_t *const left            = expression->left;
7801         expression_t *const right           = expression->right;
7802         type_t       *const orig_type_left  = left->base.type;
7803         type_t       *const orig_type_right = right->base.type;
7804         type_t       *const type_left       = skip_typeref(orig_type_left);
7805         type_t       *const type_right      = skip_typeref(orig_type_right);
7806
7807         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7808                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7809                         source_position_t const *const pos = &expression->base.source_position;
7810                         errorf(pos, "operands of binary expression must have integer types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7811                 }
7812                 return;
7813         }
7814
7815         type_t *const result_type = semantic_arithmetic(type_left, type_right);
7816         expression->left      = create_implicit_cast(left, result_type);
7817         expression->right     = create_implicit_cast(right, result_type);
7818         expression->base.type = result_type;
7819 }
7820
7821 static void warn_div_by_zero(binary_expression_t const *const expression)
7822 {
7823         if (!is_type_integer(expression->base.type))
7824                 return;
7825
7826         expression_t const *const right = expression->right;
7827         /* The type of the right operand can be different for /= */
7828         if (is_type_integer(right->base.type)                    &&
7829             is_constant_expression(right) == EXPR_CLASS_CONSTANT &&
7830             !fold_constant_to_bool(right)) {
7831                 source_position_t const *const pos = &expression->base.source_position;
7832                 warningf(WARN_DIV_BY_ZERO, pos, "division by zero");
7833         }
7834 }
7835
7836 /**
7837  * Check the semantic restrictions for a div expression.
7838  */
7839 static void semantic_div(binary_expression_t *expression)
7840 {
7841         semantic_binexpr_arithmetic(expression);
7842         warn_div_by_zero(expression);
7843 }
7844
7845 /**
7846  * Check the semantic restrictions for a mod expression.
7847  */
7848 static void semantic_mod(binary_expression_t *expression)
7849 {
7850         semantic_binexpr_integer(expression);
7851         warn_div_by_zero(expression);
7852 }
7853
7854 static void warn_addsub_in_shift(const expression_t *const expr)
7855 {
7856         if (expr->base.parenthesized)
7857                 return;
7858
7859         char op;
7860         switch (expr->kind) {
7861                 case EXPR_BINARY_ADD: op = '+'; break;
7862                 case EXPR_BINARY_SUB: op = '-'; break;
7863                 default:              return;
7864         }
7865
7866         source_position_t const *const pos = &expr->base.source_position;
7867         warningf(WARN_PARENTHESES, pos, "suggest parentheses around '%c' inside shift", op);
7868 }
7869
7870 static bool semantic_shift(binary_expression_t *expression)
7871 {
7872         expression_t *const left            = expression->left;
7873         expression_t *const right           = expression->right;
7874         type_t       *const orig_type_left  = left->base.type;
7875         type_t       *const orig_type_right = right->base.type;
7876         type_t       *      type_left       = skip_typeref(orig_type_left);
7877         type_t       *      type_right      = skip_typeref(orig_type_right);
7878
7879         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7880                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7881                         source_position_t const *const pos = &expression->base.source_position;
7882                         errorf(pos, "operands of shift expression must have integer types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7883                 }
7884                 return false;
7885         }
7886
7887         type_left = promote_integer(type_left);
7888
7889         if (is_constant_expression(right) == EXPR_CLASS_CONSTANT) {
7890                 source_position_t const *const pos   = &right->base.source_position;
7891                 long                     const count = fold_constant_to_int(right);
7892                 if (count < 0) {
7893                         warningf(WARN_OTHER, pos, "shift count must be non-negative");
7894                 } else if ((unsigned long)count >=
7895                                 get_atomic_type_size(type_left->atomic.akind) * 8) {
7896                         warningf(WARN_OTHER, pos, "shift count must be less than type width");
7897                 }
7898         }
7899
7900         type_right        = promote_integer(type_right);
7901         expression->right = create_implicit_cast(right, type_right);
7902
7903         return true;
7904 }
7905
7906 static void semantic_shift_op(binary_expression_t *expression)
7907 {
7908         expression_t *const left  = expression->left;
7909         expression_t *const right = expression->right;
7910
7911         if (!semantic_shift(expression))
7912                 return;
7913
7914         warn_addsub_in_shift(left);
7915         warn_addsub_in_shift(right);
7916
7917         type_t *const orig_type_left = left->base.type;
7918         type_t *      type_left      = skip_typeref(orig_type_left);
7919
7920         type_left             = promote_integer(type_left);
7921         expression->left      = create_implicit_cast(left, type_left);
7922         expression->base.type = type_left;
7923 }
7924
7925 static void semantic_add(binary_expression_t *expression)
7926 {
7927         expression_t *const left            = expression->left;
7928         expression_t *const right           = expression->right;
7929         type_t       *const orig_type_left  = left->base.type;
7930         type_t       *const orig_type_right = right->base.type;
7931         type_t       *const type_left       = skip_typeref(orig_type_left);
7932         type_t       *const type_right      = skip_typeref(orig_type_right);
7933
7934         /* §6.5.6 */
7935         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7936                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7937                 expression->left  = create_implicit_cast(left, arithmetic_type);
7938                 expression->right = create_implicit_cast(right, arithmetic_type);
7939                 expression->base.type = arithmetic_type;
7940         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7941                 check_pointer_arithmetic(&expression->base.source_position,
7942                                          type_left, orig_type_left);
7943                 expression->base.type = type_left;
7944         } else if (is_type_pointer(type_right) && is_type_integer(type_left)) {
7945                 check_pointer_arithmetic(&expression->base.source_position,
7946                                          type_right, orig_type_right);
7947                 expression->base.type = type_right;
7948         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7949                 errorf(&expression->base.source_position,
7950                        "invalid operands to binary + ('%T', '%T')",
7951                        orig_type_left, orig_type_right);
7952         }
7953 }
7954
7955 static void semantic_sub(binary_expression_t *expression)
7956 {
7957         expression_t            *const left            = expression->left;
7958         expression_t            *const right           = expression->right;
7959         type_t                  *const orig_type_left  = left->base.type;
7960         type_t                  *const orig_type_right = right->base.type;
7961         type_t                  *const type_left       = skip_typeref(orig_type_left);
7962         type_t                  *const type_right      = skip_typeref(orig_type_right);
7963         source_position_t const *const pos             = &expression->base.source_position;
7964
7965         /* §5.6.5 */
7966         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7967                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7968                 expression->left        = create_implicit_cast(left, arithmetic_type);
7969                 expression->right       = create_implicit_cast(right, arithmetic_type);
7970                 expression->base.type =  arithmetic_type;
7971         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7972                 check_pointer_arithmetic(&expression->base.source_position,
7973                                          type_left, orig_type_left);
7974                 expression->base.type = type_left;
7975         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
7976                 type_t *const unqual_left  = get_unqualified_type(skip_typeref(type_left->pointer.points_to));
7977                 type_t *const unqual_right = get_unqualified_type(skip_typeref(type_right->pointer.points_to));
7978                 if (!types_compatible(unqual_left, unqual_right)) {
7979                         errorf(pos,
7980                                "subtracting pointers to incompatible types '%T' and '%T'",
7981                                orig_type_left, orig_type_right);
7982                 } else if (!is_type_object(unqual_left)) {
7983                         if (!is_type_void(unqual_left)) {
7984                                 errorf(pos, "subtracting pointers to non-object types '%T'",
7985                                        orig_type_left);
7986                         } else {
7987                                 warningf(WARN_OTHER, pos, "subtracting pointers to void");
7988                         }
7989                 }
7990                 expression->base.type = type_ptrdiff_t;
7991         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7992                 errorf(pos, "invalid operands of types '%T' and '%T' to binary '-'",
7993                        orig_type_left, orig_type_right);
7994         }
7995 }
7996
7997 static void warn_string_literal_address(expression_t const* expr)
7998 {
7999         while (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
8000                 expr = expr->unary.value;
8001                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
8002                         return;
8003                 expr = expr->unary.value;
8004         }
8005
8006         if (expr->kind == EXPR_STRING_LITERAL) {
8007                 source_position_t const *const pos = &expr->base.source_position;
8008                 warningf(WARN_ADDRESS, pos, "comparison with string literal results in unspecified behaviour");
8009         }
8010 }
8011
8012 static bool maybe_negative(expression_t const *const expr)
8013 {
8014         switch (is_constant_expression(expr)) {
8015                 case EXPR_CLASS_ERROR:    return false;
8016                 case EXPR_CLASS_CONSTANT: return constant_is_negative(expr);
8017                 default:                  return true;
8018         }
8019 }
8020
8021 static void warn_comparison(source_position_t const *const pos, expression_t const *const expr, expression_t const *const other)
8022 {
8023         warn_string_literal_address(expr);
8024
8025         expression_t const* const ref = get_reference_address(expr);
8026         if (ref != NULL && is_null_pointer_constant(other)) {
8027                 entity_t const *const ent = ref->reference.entity;
8028                 warningf(WARN_ADDRESS, pos, "the address of '%N' will never be NULL", ent);
8029         }
8030
8031         if (!expr->base.parenthesized) {
8032                 switch (expr->base.kind) {
8033                         case EXPR_BINARY_LESS:
8034                         case EXPR_BINARY_GREATER:
8035                         case EXPR_BINARY_LESSEQUAL:
8036                         case EXPR_BINARY_GREATEREQUAL:
8037                         case EXPR_BINARY_NOTEQUAL:
8038                         case EXPR_BINARY_EQUAL:
8039                                 warningf(WARN_PARENTHESES, pos, "comparisons like 'x <= y < z' do not have their mathematical meaning");
8040                                 break;
8041                         default:
8042                                 break;
8043                 }
8044         }
8045 }
8046
8047 /**
8048  * Check the semantics of comparison expressions.
8049  *
8050  * @param expression   The expression to check.
8051  */
8052 static void semantic_comparison(binary_expression_t *expression)
8053 {
8054         source_position_t const *const pos   = &expression->base.source_position;
8055         expression_t            *const left  = expression->left;
8056         expression_t            *const right = expression->right;
8057
8058         warn_comparison(pos, left, right);
8059         warn_comparison(pos, right, left);
8060
8061         type_t *orig_type_left  = left->base.type;
8062         type_t *orig_type_right = right->base.type;
8063         type_t *type_left       = skip_typeref(orig_type_left);
8064         type_t *type_right      = skip_typeref(orig_type_right);
8065
8066         /* TODO non-arithmetic types */
8067         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8068                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8069
8070                 /* test for signed vs unsigned compares */
8071                 if (is_type_integer(arithmetic_type)) {
8072                         bool const signed_left  = is_type_signed(type_left);
8073                         bool const signed_right = is_type_signed(type_right);
8074                         if (signed_left != signed_right) {
8075                                 /* FIXME long long needs better const folding magic */
8076                                 /* TODO check whether constant value can be represented by other type */
8077                                 if ((signed_left  && maybe_negative(left)) ||
8078                                                 (signed_right && maybe_negative(right))) {
8079                                         warningf(WARN_SIGN_COMPARE, pos, "comparison between signed and unsigned");
8080                                 }
8081                         }
8082                 }
8083
8084                 expression->left        = create_implicit_cast(left, arithmetic_type);
8085                 expression->right       = create_implicit_cast(right, arithmetic_type);
8086                 expression->base.type   = arithmetic_type;
8087                 if ((expression->base.kind == EXPR_BINARY_EQUAL ||
8088                      expression->base.kind == EXPR_BINARY_NOTEQUAL) &&
8089                     is_type_float(arithmetic_type)) {
8090                         warningf(WARN_FLOAT_EQUAL, pos, "comparing floating point with == or != is unsafe");
8091                 }
8092         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
8093                 /* TODO check compatibility */
8094         } else if (is_type_pointer(type_left)) {
8095                 expression->right = create_implicit_cast(right, type_left);
8096         } else if (is_type_pointer(type_right)) {
8097                 expression->left = create_implicit_cast(left, type_right);
8098         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8099                 type_error_incompatible("invalid operands in comparison", pos, type_left, type_right);
8100         }
8101         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8102 }
8103
8104 /**
8105  * Checks if a compound type has constant fields.
8106  */
8107 static bool has_const_fields(const compound_type_t *type)
8108 {
8109         compound_t *compound = type->compound;
8110         entity_t   *entry    = compound->members.entities;
8111
8112         for (; entry != NULL; entry = entry->base.next) {
8113                 if (!is_declaration(entry))
8114                         continue;
8115
8116                 const type_t *decl_type = skip_typeref(entry->declaration.type);
8117                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
8118                         return true;
8119         }
8120
8121         return false;
8122 }
8123
8124 static bool is_valid_assignment_lhs(expression_t const* const left)
8125 {
8126         type_t *const orig_type_left = revert_automatic_type_conversion(left);
8127         type_t *const type_left      = skip_typeref(orig_type_left);
8128
8129         if (!is_lvalue(left)) {
8130                 errorf(&left->base.source_position, "left hand side '%E' of assignment is not an lvalue",
8131                        left);
8132                 return false;
8133         }
8134
8135         if (left->kind == EXPR_REFERENCE
8136                         && left->reference.entity->kind == ENTITY_FUNCTION) {
8137                 errorf(&left->base.source_position, "cannot assign to function '%E'", left);
8138                 return false;
8139         }
8140
8141         if (is_type_array(type_left)) {
8142                 errorf(&left->base.source_position, "cannot assign to array '%E'", left);
8143                 return false;
8144         }
8145         if (type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
8146                 errorf(&left->base.source_position, "assignment to read-only location '%E' (type '%T')", left,
8147                        orig_type_left);
8148                 return false;
8149         }
8150         if (is_type_incomplete(type_left)) {
8151                 errorf(&left->base.source_position, "left-hand side '%E' of assignment has incomplete type '%T'",
8152                        left, orig_type_left);
8153                 return false;
8154         }
8155         if (is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
8156                 errorf(&left->base.source_position, "cannot assign to '%E' because compound type '%T' has read-only fields",
8157                        left, orig_type_left);
8158                 return false;
8159         }
8160
8161         return true;
8162 }
8163
8164 static void semantic_arithmetic_assign(binary_expression_t *expression)
8165 {
8166         expression_t *left            = expression->left;
8167         expression_t *right           = expression->right;
8168         type_t       *orig_type_left  = left->base.type;
8169         type_t       *orig_type_right = right->base.type;
8170
8171         if (!is_valid_assignment_lhs(left))
8172                 return;
8173
8174         type_t *type_left  = skip_typeref(orig_type_left);
8175         type_t *type_right = skip_typeref(orig_type_right);
8176
8177         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
8178                 /* TODO: improve error message */
8179                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8180                         errorf(&expression->base.source_position,
8181                                "operation needs arithmetic types");
8182                 }
8183                 return;
8184         }
8185
8186         /* combined instructions are tricky. We can't create an implicit cast on
8187          * the left side, because we need the uncasted form for the store.
8188          * The ast2firm pass has to know that left_type must be right_type
8189          * for the arithmetic operation and create a cast by itself */
8190         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8191         expression->right       = create_implicit_cast(right, arithmetic_type);
8192         expression->base.type   = type_left;
8193 }
8194
8195 static void semantic_divmod_assign(binary_expression_t *expression)
8196 {
8197         semantic_arithmetic_assign(expression);
8198         warn_div_by_zero(expression);
8199 }
8200
8201 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
8202 {
8203         expression_t *const left            = expression->left;
8204         expression_t *const right           = expression->right;
8205         type_t       *const orig_type_left  = left->base.type;
8206         type_t       *const orig_type_right = right->base.type;
8207         type_t       *const type_left       = skip_typeref(orig_type_left);
8208         type_t       *const type_right      = skip_typeref(orig_type_right);
8209
8210         if (!is_valid_assignment_lhs(left))
8211                 return;
8212
8213         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8214                 /* combined instructions are tricky. We can't create an implicit cast on
8215                  * the left side, because we need the uncasted form for the store.
8216                  * The ast2firm pass has to know that left_type must be right_type
8217                  * for the arithmetic operation and create a cast by itself */
8218                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
8219                 expression->right     = create_implicit_cast(right, arithmetic_type);
8220                 expression->base.type = type_left;
8221         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
8222                 check_pointer_arithmetic(&expression->base.source_position,
8223                                          type_left, orig_type_left);
8224                 expression->base.type = type_left;
8225         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8226                 errorf(&expression->base.source_position,
8227                        "incompatible types '%T' and '%T' in assignment",
8228                        orig_type_left, orig_type_right);
8229         }
8230 }
8231
8232 static void semantic_integer_assign(binary_expression_t *expression)
8233 {
8234         expression_t *left            = expression->left;
8235         expression_t *right           = expression->right;
8236         type_t       *orig_type_left  = left->base.type;
8237         type_t       *orig_type_right = right->base.type;
8238
8239         if (!is_valid_assignment_lhs(left))
8240                 return;
8241
8242         type_t *type_left  = skip_typeref(orig_type_left);
8243         type_t *type_right = skip_typeref(orig_type_right);
8244
8245         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
8246                 /* TODO: improve error message */
8247                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8248                         errorf(&expression->base.source_position,
8249                                "operation needs integer types");
8250                 }
8251                 return;
8252         }
8253
8254         /* combined instructions are tricky. We can't create an implicit cast on
8255          * the left side, because we need the uncasted form for the store.
8256          * The ast2firm pass has to know that left_type must be right_type
8257          * for the arithmetic operation and create a cast by itself */
8258         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8259         expression->right       = create_implicit_cast(right, arithmetic_type);
8260         expression->base.type   = type_left;
8261 }
8262
8263 static void semantic_shift_assign(binary_expression_t *expression)
8264 {
8265         expression_t *left           = expression->left;
8266
8267         if (!is_valid_assignment_lhs(left))
8268                 return;
8269
8270         if (!semantic_shift(expression))
8271                 return;
8272
8273         expression->base.type = skip_typeref(left->base.type);
8274 }
8275
8276 static void warn_logical_and_within_or(const expression_t *const expr)
8277 {
8278         if (expr->base.kind != EXPR_BINARY_LOGICAL_AND)
8279                 return;
8280         if (expr->base.parenthesized)
8281                 return;
8282         source_position_t const *const pos = &expr->base.source_position;
8283         warningf(WARN_PARENTHESES, pos, "suggest parentheses around && within ||");
8284 }
8285
8286 /**
8287  * Check the semantic restrictions of a logical expression.
8288  */
8289 static void semantic_logical_op(binary_expression_t *expression)
8290 {
8291         /* §6.5.13:2  Each of the operands shall have scalar type.
8292          * §6.5.14:2  Each of the operands shall have scalar type. */
8293         semantic_condition(expression->left,   "left operand of logical operator");
8294         semantic_condition(expression->right, "right operand of logical operator");
8295         if (expression->base.kind == EXPR_BINARY_LOGICAL_OR) {
8296                 warn_logical_and_within_or(expression->left);
8297                 warn_logical_and_within_or(expression->right);
8298         }
8299         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8300 }
8301
8302 /**
8303  * Check the semantic restrictions of a binary assign expression.
8304  */
8305 static void semantic_binexpr_assign(binary_expression_t *expression)
8306 {
8307         expression_t *left           = expression->left;
8308         type_t       *orig_type_left = left->base.type;
8309
8310         if (!is_valid_assignment_lhs(left))
8311                 return;
8312
8313         assign_error_t error = semantic_assign(orig_type_left, expression->right);
8314         report_assign_error(error, orig_type_left, expression->right,
8315                         "assignment", &left->base.source_position);
8316         expression->right = create_implicit_cast(expression->right, orig_type_left);
8317         expression->base.type = orig_type_left;
8318 }
8319
8320 /**
8321  * Determine if the outermost operation (or parts thereof) of the given
8322  * expression has no effect in order to generate a warning about this fact.
8323  * Therefore in some cases this only examines some of the operands of the
8324  * expression (see comments in the function and examples below).
8325  * Examples:
8326  *   f() + 23;    // warning, because + has no effect
8327  *   x || f();    // no warning, because x controls execution of f()
8328  *   x ? y : f(); // warning, because y has no effect
8329  *   (void)x;     // no warning to be able to suppress the warning
8330  * This function can NOT be used for an "expression has definitely no effect"-
8331  * analysis. */
8332 static bool expression_has_effect(const expression_t *const expr)
8333 {
8334         switch (expr->kind) {
8335                 case EXPR_ERROR:                      return true; /* do NOT warn */
8336                 case EXPR_REFERENCE:                  return false;
8337                 case EXPR_ENUM_CONSTANT:              return false;
8338                 case EXPR_LABEL_ADDRESS:              return false;
8339
8340                 /* suppress the warning for microsoft __noop operations */
8341                 case EXPR_LITERAL_MS_NOOP:            return true;
8342                 case EXPR_LITERAL_BOOLEAN:
8343                 case EXPR_LITERAL_CHARACTER:
8344                 case EXPR_LITERAL_INTEGER:
8345                 case EXPR_LITERAL_FLOATINGPOINT:
8346                 case EXPR_STRING_LITERAL:             return false;
8347
8348                 case EXPR_CALL: {
8349                         const call_expression_t *const call = &expr->call;
8350                         if (call->function->kind != EXPR_REFERENCE)
8351                                 return true;
8352
8353                         switch (call->function->reference.entity->function.btk) {
8354                                 /* FIXME: which builtins have no effect? */
8355                                 default:                      return true;
8356                         }
8357                 }
8358
8359                 /* Generate the warning if either the left or right hand side of a
8360                  * conditional expression has no effect */
8361                 case EXPR_CONDITIONAL: {
8362                         conditional_expression_t const *const cond = &expr->conditional;
8363                         expression_t             const *const t    = cond->true_expression;
8364                         return
8365                                 (t == NULL || expression_has_effect(t)) &&
8366                                 expression_has_effect(cond->false_expression);
8367                 }
8368
8369                 case EXPR_SELECT:                     return false;
8370                 case EXPR_ARRAY_ACCESS:               return false;
8371                 case EXPR_SIZEOF:                     return false;
8372                 case EXPR_CLASSIFY_TYPE:              return false;
8373                 case EXPR_ALIGNOF:                    return false;
8374
8375                 case EXPR_FUNCNAME:                   return false;
8376                 case EXPR_BUILTIN_CONSTANT_P:         return false;
8377                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P: return false;
8378                 case EXPR_OFFSETOF:                   return false;
8379                 case EXPR_VA_START:                   return true;
8380                 case EXPR_VA_ARG:                     return true;
8381                 case EXPR_VA_COPY:                    return true;
8382                 case EXPR_STATEMENT:                  return true; // TODO
8383                 case EXPR_COMPOUND_LITERAL:           return false;
8384
8385                 case EXPR_UNARY_NEGATE:               return false;
8386                 case EXPR_UNARY_PLUS:                 return false;
8387                 case EXPR_UNARY_BITWISE_NEGATE:       return false;
8388                 case EXPR_UNARY_NOT:                  return false;
8389                 case EXPR_UNARY_DEREFERENCE:          return false;
8390                 case EXPR_UNARY_TAKE_ADDRESS:         return false;
8391                 case EXPR_UNARY_POSTFIX_INCREMENT:    return true;
8392                 case EXPR_UNARY_POSTFIX_DECREMENT:    return true;
8393                 case EXPR_UNARY_PREFIX_INCREMENT:     return true;
8394                 case EXPR_UNARY_PREFIX_DECREMENT:     return true;
8395
8396                 /* Treat void casts as if they have an effect in order to being able to
8397                  * suppress the warning */
8398                 case EXPR_UNARY_CAST: {
8399                         type_t *const type = skip_typeref(expr->base.type);
8400                         return is_type_void(type);
8401                 }
8402
8403                 case EXPR_UNARY_ASSUME:               return true;
8404                 case EXPR_UNARY_DELETE:               return true;
8405                 case EXPR_UNARY_DELETE_ARRAY:         return true;
8406                 case EXPR_UNARY_THROW:                return true;
8407
8408                 case EXPR_BINARY_ADD:                 return false;
8409                 case EXPR_BINARY_SUB:                 return false;
8410                 case EXPR_BINARY_MUL:                 return false;
8411                 case EXPR_BINARY_DIV:                 return false;
8412                 case EXPR_BINARY_MOD:                 return false;
8413                 case EXPR_BINARY_EQUAL:               return false;
8414                 case EXPR_BINARY_NOTEQUAL:            return false;
8415                 case EXPR_BINARY_LESS:                return false;
8416                 case EXPR_BINARY_LESSEQUAL:           return false;
8417                 case EXPR_BINARY_GREATER:             return false;
8418                 case EXPR_BINARY_GREATEREQUAL:        return false;
8419                 case EXPR_BINARY_BITWISE_AND:         return false;
8420                 case EXPR_BINARY_BITWISE_OR:          return false;
8421                 case EXPR_BINARY_BITWISE_XOR:         return false;
8422                 case EXPR_BINARY_SHIFTLEFT:           return false;
8423                 case EXPR_BINARY_SHIFTRIGHT:          return false;
8424                 case EXPR_BINARY_ASSIGN:              return true;
8425                 case EXPR_BINARY_MUL_ASSIGN:          return true;
8426                 case EXPR_BINARY_DIV_ASSIGN:          return true;
8427                 case EXPR_BINARY_MOD_ASSIGN:          return true;
8428                 case EXPR_BINARY_ADD_ASSIGN:          return true;
8429                 case EXPR_BINARY_SUB_ASSIGN:          return true;
8430                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:    return true;
8431                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:   return true;
8432                 case EXPR_BINARY_BITWISE_AND_ASSIGN:  return true;
8433                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:  return true;
8434                 case EXPR_BINARY_BITWISE_OR_ASSIGN:   return true;
8435
8436                 /* Only examine the right hand side of && and ||, because the left hand
8437                  * side already has the effect of controlling the execution of the right
8438                  * hand side */
8439                 case EXPR_BINARY_LOGICAL_AND:
8440                 case EXPR_BINARY_LOGICAL_OR:
8441                 /* Only examine the right hand side of a comma expression, because the left
8442                  * hand side has a separate warning */
8443                 case EXPR_BINARY_COMMA:
8444                         return expression_has_effect(expr->binary.right);
8445
8446                 case EXPR_BINARY_ISGREATER:           return false;
8447                 case EXPR_BINARY_ISGREATEREQUAL:      return false;
8448                 case EXPR_BINARY_ISLESS:              return false;
8449                 case EXPR_BINARY_ISLESSEQUAL:         return false;
8450                 case EXPR_BINARY_ISLESSGREATER:       return false;
8451                 case EXPR_BINARY_ISUNORDERED:         return false;
8452         }
8453
8454         internal_errorf(HERE, "unexpected expression");
8455 }
8456
8457 static void semantic_comma(binary_expression_t *expression)
8458 {
8459         const expression_t *const left = expression->left;
8460         if (!expression_has_effect(left)) {
8461                 source_position_t const *const pos = &left->base.source_position;
8462                 warningf(WARN_UNUSED_VALUE, pos, "left-hand operand of comma expression has no effect");
8463         }
8464         expression->base.type = expression->right->base.type;
8465 }
8466
8467 /**
8468  * @param prec_r precedence of the right operand
8469  */
8470 #define CREATE_BINEXPR_PARSER(token_kind, binexpression_type, prec_r, sfunc) \
8471 static expression_t *parse_##binexpression_type(expression_t *left)          \
8472 {                                                                            \
8473         expression_t *binexpr = allocate_expression_zero(binexpression_type);    \
8474         binexpr->binary.left  = left;                                            \
8475         eat(token_kind);                                                         \
8476                                                                              \
8477         expression_t *right = parse_subexpression(prec_r);                       \
8478                                                                              \
8479         binexpr->binary.right = right;                                           \
8480         sfunc(&binexpr->binary);                                                 \
8481                                                                              \
8482         return binexpr;                                                          \
8483 }
8484
8485 CREATE_BINEXPR_PARSER('*',                    EXPR_BINARY_MUL,                PREC_CAST,           semantic_binexpr_arithmetic)
8486 CREATE_BINEXPR_PARSER('/',                    EXPR_BINARY_DIV,                PREC_CAST,           semantic_div)
8487 CREATE_BINEXPR_PARSER('%',                    EXPR_BINARY_MOD,                PREC_CAST,           semantic_mod)
8488 CREATE_BINEXPR_PARSER('+',                    EXPR_BINARY_ADD,                PREC_MULTIPLICATIVE, semantic_add)
8489 CREATE_BINEXPR_PARSER('-',                    EXPR_BINARY_SUB,                PREC_MULTIPLICATIVE, semantic_sub)
8490 CREATE_BINEXPR_PARSER(T_LESSLESS,             EXPR_BINARY_SHIFTLEFT,          PREC_ADDITIVE,       semantic_shift_op)
8491 CREATE_BINEXPR_PARSER(T_GREATERGREATER,       EXPR_BINARY_SHIFTRIGHT,         PREC_ADDITIVE,       semantic_shift_op)
8492 CREATE_BINEXPR_PARSER('<',                    EXPR_BINARY_LESS,               PREC_SHIFT,          semantic_comparison)
8493 CREATE_BINEXPR_PARSER('>',                    EXPR_BINARY_GREATER,            PREC_SHIFT,          semantic_comparison)
8494 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,          PREC_SHIFT,          semantic_comparison)
8495 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,       PREC_SHIFT,          semantic_comparison)
8496 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,           PREC_RELATIONAL,     semantic_comparison)
8497 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,              PREC_RELATIONAL,     semantic_comparison)
8498 CREATE_BINEXPR_PARSER('&',                    EXPR_BINARY_BITWISE_AND,        PREC_EQUALITY,       semantic_binexpr_integer)
8499 CREATE_BINEXPR_PARSER('^',                    EXPR_BINARY_BITWISE_XOR,        PREC_AND,            semantic_binexpr_integer)
8500 CREATE_BINEXPR_PARSER('|',                    EXPR_BINARY_BITWISE_OR,         PREC_XOR,            semantic_binexpr_integer)
8501 CREATE_BINEXPR_PARSER(T_ANDAND,               EXPR_BINARY_LOGICAL_AND,        PREC_OR,             semantic_logical_op)
8502 CREATE_BINEXPR_PARSER(T_PIPEPIPE,             EXPR_BINARY_LOGICAL_OR,         PREC_LOGICAL_AND,    semantic_logical_op)
8503 CREATE_BINEXPR_PARSER('=',                    EXPR_BINARY_ASSIGN,             PREC_ASSIGNMENT,     semantic_binexpr_assign)
8504 CREATE_BINEXPR_PARSER(T_PLUSEQUAL,            EXPR_BINARY_ADD_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8505 CREATE_BINEXPR_PARSER(T_MINUSEQUAL,           EXPR_BINARY_SUB_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8506 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL,        EXPR_BINARY_MUL_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_assign)
8507 CREATE_BINEXPR_PARSER(T_SLASHEQUAL,           EXPR_BINARY_DIV_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8508 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL,         EXPR_BINARY_MOD_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8509 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL,        EXPR_BINARY_SHIFTLEFT_ASSIGN,   PREC_ASSIGNMENT,     semantic_shift_assign)
8510 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL,  EXPR_BINARY_SHIFTRIGHT_ASSIGN,  PREC_ASSIGNMENT,     semantic_shift_assign)
8511 CREATE_BINEXPR_PARSER(T_ANDEQUAL,             EXPR_BINARY_BITWISE_AND_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8512 CREATE_BINEXPR_PARSER(T_PIPEEQUAL,            EXPR_BINARY_BITWISE_OR_ASSIGN,  PREC_ASSIGNMENT,     semantic_integer_assign)
8513 CREATE_BINEXPR_PARSER(T_CARETEQUAL,           EXPR_BINARY_BITWISE_XOR_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8514 CREATE_BINEXPR_PARSER(',',                    EXPR_BINARY_COMMA,              PREC_ASSIGNMENT,     semantic_comma)
8515
8516
8517 static expression_t *parse_subexpression(precedence_t precedence)
8518 {
8519         expression_parser_function_t *parser
8520                 = &expression_parsers[token.kind];
8521         expression_t                 *left;
8522
8523         if (parser->parser != NULL) {
8524                 left = parser->parser();
8525         } else {
8526                 left = parse_primary_expression();
8527         }
8528         assert(left != NULL);
8529
8530         while (true) {
8531                 parser = &expression_parsers[token.kind];
8532                 if (parser->infix_parser == NULL)
8533                         break;
8534                 if (parser->infix_precedence < precedence)
8535                         break;
8536
8537                 left = parser->infix_parser(left);
8538
8539                 assert(left != NULL);
8540         }
8541
8542         return left;
8543 }
8544
8545 /**
8546  * Parse an expression.
8547  */
8548 static expression_t *parse_expression(void)
8549 {
8550         return parse_subexpression(PREC_EXPRESSION);
8551 }
8552
8553 /**
8554  * Register a parser for a prefix-like operator.
8555  *
8556  * @param parser      the parser function
8557  * @param token_kind  the token type of the prefix token
8558  */
8559 static void register_expression_parser(parse_expression_function parser,
8560                                        int token_kind)
8561 {
8562         expression_parser_function_t *entry = &expression_parsers[token_kind];
8563
8564         assert(!entry->parser);
8565         entry->parser = parser;
8566 }
8567
8568 /**
8569  * Register a parser for an infix operator with given precedence.
8570  *
8571  * @param parser      the parser function
8572  * @param token_kind  the token type of the infix operator
8573  * @param precedence  the precedence of the operator
8574  */
8575 static void register_infix_parser(parse_expression_infix_function parser,
8576                                   int token_kind, precedence_t precedence)
8577 {
8578         expression_parser_function_t *entry = &expression_parsers[token_kind];
8579
8580         assert(!entry->infix_parser);
8581         entry->infix_parser     = parser;
8582         entry->infix_precedence = precedence;
8583 }
8584
8585 /**
8586  * Initialize the expression parsers.
8587  */
8588 static void init_expression_parsers(void)
8589 {
8590         memset(&expression_parsers, 0, sizeof(expression_parsers));
8591
8592         register_infix_parser(parse_array_expression,               '[',                    PREC_POSTFIX);
8593         register_infix_parser(parse_call_expression,                '(',                    PREC_POSTFIX);
8594         register_infix_parser(parse_select_expression,              '.',                    PREC_POSTFIX);
8595         register_infix_parser(parse_select_expression,              T_MINUSGREATER,         PREC_POSTFIX);
8596         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,   T_PLUSPLUS,             PREC_POSTFIX);
8597         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,   T_MINUSMINUS,           PREC_POSTFIX);
8598         register_infix_parser(parse_EXPR_BINARY_MUL,                '*',                    PREC_MULTIPLICATIVE);
8599         register_infix_parser(parse_EXPR_BINARY_DIV,                '/',                    PREC_MULTIPLICATIVE);
8600         register_infix_parser(parse_EXPR_BINARY_MOD,                '%',                    PREC_MULTIPLICATIVE);
8601         register_infix_parser(parse_EXPR_BINARY_ADD,                '+',                    PREC_ADDITIVE);
8602         register_infix_parser(parse_EXPR_BINARY_SUB,                '-',                    PREC_ADDITIVE);
8603         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,          T_LESSLESS,             PREC_SHIFT);
8604         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,         T_GREATERGREATER,       PREC_SHIFT);
8605         register_infix_parser(parse_EXPR_BINARY_LESS,               '<',                    PREC_RELATIONAL);
8606         register_infix_parser(parse_EXPR_BINARY_GREATER,            '>',                    PREC_RELATIONAL);
8607         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,          T_LESSEQUAL,            PREC_RELATIONAL);
8608         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL,       T_GREATEREQUAL,         PREC_RELATIONAL);
8609         register_infix_parser(parse_EXPR_BINARY_EQUAL,              T_EQUALEQUAL,           PREC_EQUALITY);
8610         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,           T_EXCLAMATIONMARKEQUAL, PREC_EQUALITY);
8611         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,        '&',                    PREC_AND);
8612         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,        '^',                    PREC_XOR);
8613         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,         '|',                    PREC_OR);
8614         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,        T_ANDAND,               PREC_LOGICAL_AND);
8615         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,         T_PIPEPIPE,             PREC_LOGICAL_OR);
8616         register_infix_parser(parse_conditional_expression,         '?',                    PREC_CONDITIONAL);
8617         register_infix_parser(parse_EXPR_BINARY_ASSIGN,             '=',                    PREC_ASSIGNMENT);
8618         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,         T_PLUSEQUAL,            PREC_ASSIGNMENT);
8619         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,         T_MINUSEQUAL,           PREC_ASSIGNMENT);
8620         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,         T_ASTERISKEQUAL,        PREC_ASSIGNMENT);
8621         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,         T_SLASHEQUAL,           PREC_ASSIGNMENT);
8622         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,         T_PERCENTEQUAL,         PREC_ASSIGNMENT);
8623         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,   T_LESSLESSEQUAL,        PREC_ASSIGNMENT);
8624         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,  T_GREATERGREATEREQUAL,  PREC_ASSIGNMENT);
8625         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN, T_ANDEQUAL,             PREC_ASSIGNMENT);
8626         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,  T_PIPEEQUAL,            PREC_ASSIGNMENT);
8627         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN, T_CARETEQUAL,           PREC_ASSIGNMENT);
8628         register_infix_parser(parse_EXPR_BINARY_COMMA,              ',',                    PREC_EXPRESSION);
8629
8630         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-');
8631         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+');
8632         register_expression_parser(parse_EXPR_UNARY_NOT,              '!');
8633         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~');
8634         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*');
8635         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&');
8636         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT, T_PLUSPLUS);
8637         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT, T_MINUSMINUS);
8638         register_expression_parser(parse_sizeof,                      T_sizeof);
8639         register_expression_parser(parse_alignof,                     T__Alignof);
8640         register_expression_parser(parse_extension,                   T___extension__);
8641         register_expression_parser(parse_builtin_classify_type,       T___builtin_classify_type);
8642         register_expression_parser(parse_delete,                      T_delete);
8643         register_expression_parser(parse_throw,                       T_throw);
8644 }
8645
8646 /**
8647  * Parse a asm statement arguments specification.
8648  */
8649 static void parse_asm_arguments(asm_argument_t **anchor, bool const is_out)
8650 {
8651         if (token.kind == T_STRING_LITERAL || token.kind == '[') {
8652                 add_anchor_token(',');
8653                 do {
8654                         asm_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
8655
8656                         add_anchor_token(')');
8657                         add_anchor_token('(');
8658                         add_anchor_token(T_STRING_LITERAL);
8659
8660                         if (accept('[')) {
8661                                 add_anchor_token(']');
8662                                 argument->symbol = expect_identifier("while parsing asm argument", NULL);
8663                                 rem_anchor_token(']');
8664                                 expect(']');
8665                         }
8666
8667                         rem_anchor_token(T_STRING_LITERAL);
8668                         argument->constraints = parse_string_literals("asm argument");
8669                         rem_anchor_token('(');
8670                         expect('(');
8671                         expression_t *expression = parse_expression();
8672                         if (is_out) {
8673                                 /* Ugly GCC stuff: Allow lvalue casts.  Skip casts, when they do not
8674                                  * change size or type representation (e.g. int -> long is ok, but
8675                                  * int -> float is not) */
8676                                 if (expression->kind == EXPR_UNARY_CAST) {
8677                                         type_t      *const type = expression->base.type;
8678                                         type_kind_t  const kind = type->kind;
8679                                         if (kind == TYPE_ATOMIC || kind == TYPE_POINTER) {
8680                                                 unsigned flags;
8681                                                 unsigned size;
8682                                                 if (kind == TYPE_ATOMIC) {
8683                                                         atomic_type_kind_t const akind = type->atomic.akind;
8684                                                         flags = get_atomic_type_flags(akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8685                                                         size  = get_atomic_type_size(akind);
8686                                                 } else {
8687                                                         flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8688                                                         size  = get_type_size(type_void_ptr);
8689                                                 }
8690
8691                                                 do {
8692                                                         expression_t *const value      = expression->unary.value;
8693                                                         type_t       *const value_type = value->base.type;
8694                                                         type_kind_t   const value_kind = value_type->kind;
8695
8696                                                         unsigned value_flags;
8697                                                         unsigned value_size;
8698                                                         if (value_kind == TYPE_ATOMIC) {
8699                                                                 atomic_type_kind_t const value_akind = value_type->atomic.akind;
8700                                                                 value_flags = get_atomic_type_flags(value_akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8701                                                                 value_size  = get_atomic_type_size(value_akind);
8702                                                         } else if (value_kind == TYPE_POINTER) {
8703                                                                 value_flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8704                                                                 value_size  = get_type_size(type_void_ptr);
8705                                                         } else {
8706                                                                 break;
8707                                                         }
8708
8709                                                         if (value_flags != flags || value_size != size)
8710                                                                 break;
8711
8712                                                         expression = value;
8713                                                 } while (expression->kind == EXPR_UNARY_CAST);
8714                                         }
8715                                 }
8716
8717                                 if (!is_lvalue(expression))
8718                                         errorf(&expression->base.source_position, "asm output argument is not an lvalue");
8719
8720                                 if (argument->constraints.begin[0] == '=')
8721                                         determine_lhs_ent(expression, NULL);
8722                                 else
8723                                         mark_vars_read(expression, NULL);
8724                         } else {
8725                                 mark_vars_read(expression, NULL);
8726                         }
8727                         argument->expression = expression;
8728                         rem_anchor_token(')');
8729                         expect(')');
8730
8731                         set_address_taken(expression, true);
8732
8733                         *anchor = argument;
8734                         anchor  = &argument->next;
8735                 } while (accept(','));
8736                 rem_anchor_token(',');
8737         }
8738 }
8739
8740 /**
8741  * Parse a asm statement clobber specification.
8742  */
8743 static void parse_asm_clobbers(asm_clobber_t **anchor)
8744 {
8745         if (token.kind == T_STRING_LITERAL) {
8746                 add_anchor_token(',');
8747                 do {
8748                         asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
8749                         clobber->clobber       = parse_string_literals(NULL);
8750
8751                         *anchor = clobber;
8752                         anchor  = &clobber->next;
8753                 } while (accept(','));
8754                 rem_anchor_token(',');
8755         }
8756 }
8757
8758 static void parse_asm_labels(asm_label_t **anchor)
8759 {
8760         if (token.kind == T_IDENTIFIER) {
8761                 add_anchor_token(',');
8762                 do {
8763                         label_t *const label = get_label("while parsing 'asm goto' labels");
8764                         if (label) {
8765                                 asm_label_t *const asm_label = allocate_ast_zero(sizeof(*asm_label));
8766                                 asm_label->label = label;
8767
8768                                 *anchor = asm_label;
8769                                 anchor  = &asm_label->next;
8770                         }
8771                 } while (accept(','));
8772                 rem_anchor_token(',');
8773         }
8774 }
8775
8776 /**
8777  * Parse an asm statement.
8778  */
8779 static statement_t *parse_asm_statement(void)
8780 {
8781         statement_t     *statement     = allocate_statement_zero(STATEMENT_ASM);
8782         asm_statement_t *asm_statement = &statement->asms;
8783
8784         eat(T_asm);
8785         add_anchor_token(')');
8786         add_anchor_token(':');
8787         add_anchor_token(T_STRING_LITERAL);
8788
8789         if (accept(T_volatile))
8790                 asm_statement->is_volatile = true;
8791
8792         bool const asm_goto = accept(T_goto);
8793
8794         expect('(');
8795         rem_anchor_token(T_STRING_LITERAL);
8796         asm_statement->asm_text = parse_string_literals("asm statement");
8797
8798         if (accept(':')) parse_asm_arguments(&asm_statement->outputs, true);
8799         if (accept(':')) parse_asm_arguments(&asm_statement->inputs, false);
8800         if (accept(':')) parse_asm_clobbers( &asm_statement->clobbers);
8801
8802         rem_anchor_token(':');
8803         if (accept(':')) {
8804                 if (!asm_goto)
8805                         warningf(WARN_OTHER, &statement->base.source_position, "assembler statement with labels should be 'asm goto'");
8806                 parse_asm_labels(&asm_statement->labels);
8807                 if (asm_statement->labels)
8808                         errorf(&statement->base.source_position, "'asm goto' not supported");
8809         } else {
8810                 if (asm_goto)
8811                         warningf(WARN_OTHER, &statement->base.source_position, "'asm goto' without labels");
8812         }
8813
8814         rem_anchor_token(')');
8815         expect(')');
8816         expect(';');
8817
8818         if (asm_statement->outputs == NULL) {
8819                 /* GCC: An 'asm' instruction without any output operands will be treated
8820                  * identically to a volatile 'asm' instruction. */
8821                 asm_statement->is_volatile = true;
8822         }
8823
8824         return statement;
8825 }
8826
8827 static statement_t *parse_label_inner_statement(statement_t const *const label, char const *const label_kind)
8828 {
8829         statement_t *inner_stmt;
8830         switch (token.kind) {
8831                 case '}':
8832                         errorf(&label->base.source_position, "%s at end of compound statement", label_kind);
8833                         inner_stmt = create_error_statement();
8834                         break;
8835
8836                 case ';':
8837                         if (label->kind == STATEMENT_LABEL) {
8838                                 /* Eat an empty statement here, to avoid the warning about an empty
8839                                  * statement after a label.  label:; is commonly used to have a label
8840                                  * before a closing brace. */
8841                                 inner_stmt = create_empty_statement();
8842                                 eat(';');
8843                                 break;
8844                         }
8845                         /* FALLTHROUGH */
8846
8847                 default:
8848                         inner_stmt = parse_statement();
8849                         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
8850                         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
8851                         if (inner_stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
8852                                 errorf(&inner_stmt->base.source_position, "declaration after %s", label_kind);
8853                         }
8854                         break;
8855         }
8856         return inner_stmt;
8857 }
8858
8859 /**
8860  * Parse a case statement.
8861  */
8862 static statement_t *parse_case_statement(void)
8863 {
8864         statement_t       *const statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8865         source_position_t *const pos       = &statement->base.source_position;
8866
8867         eat(T_case);
8868         add_anchor_token(':');
8869
8870         expression_t *expression = parse_expression();
8871         type_t *expression_type = expression->base.type;
8872         type_t *skipped         = skip_typeref(expression_type);
8873         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8874                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8875                        expression, expression_type);
8876         }
8877
8878         type_t *type = expression_type;
8879         if (current_switch != NULL) {
8880                 type_t *switch_type = current_switch->expression->base.type;
8881                 if (is_type_valid(switch_type)) {
8882                         expression = create_implicit_cast(expression, switch_type);
8883                 }
8884         }
8885
8886         statement->case_label.expression = expression;
8887         expression_classification_t const expr_class = is_constant_expression(expression);
8888         if (expr_class != EXPR_CLASS_CONSTANT) {
8889                 if (expr_class != EXPR_CLASS_ERROR) {
8890                         errorf(pos, "case label does not reduce to an integer constant");
8891                 }
8892                 statement->case_label.is_bad = true;
8893         } else {
8894                 ir_tarval *val = fold_constant_to_tarval(expression);
8895                 statement->case_label.first_case = val;
8896                 statement->case_label.last_case  = val;
8897         }
8898
8899         if (GNU_MODE) {
8900                 if (accept(T_DOTDOTDOT)) {
8901                         expression_t *end_range = parse_expression();
8902                         expression_type = expression->base.type;
8903                         skipped         = skip_typeref(expression_type);
8904                         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8905                                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8906                                            expression, expression_type);
8907                         }
8908
8909                         end_range = create_implicit_cast(end_range, type);
8910                         statement->case_label.end_range = end_range;
8911                         expression_classification_t const end_class = is_constant_expression(end_range);
8912                         if (end_class != EXPR_CLASS_CONSTANT) {
8913                                 if (end_class != EXPR_CLASS_ERROR) {
8914                                         errorf(pos, "case range does not reduce to an integer constant");
8915                                 }
8916                                 statement->case_label.is_bad = true;
8917                         } else {
8918                                 ir_tarval *val = fold_constant_to_tarval(end_range);
8919                                 statement->case_label.last_case = val;
8920
8921                                 if (tarval_cmp(val, statement->case_label.first_case)
8922                                     == ir_relation_less) {
8923                                         statement->case_label.is_empty_range = true;
8924                                         warningf(WARN_OTHER, pos, "empty range specified");
8925                                 }
8926                         }
8927                 }
8928         }
8929
8930         PUSH_PARENT(statement);
8931
8932         rem_anchor_token(':');
8933         expect(':');
8934
8935         if (current_switch != NULL) {
8936                 if (! statement->case_label.is_bad) {
8937                         /* Check for duplicate case values */
8938                         case_label_statement_t *c = &statement->case_label;
8939                         for (case_label_statement_t *l = current_switch->first_case; l != NULL; l = l->next) {
8940                                 if (l->is_bad || l->is_empty_range || l->expression == NULL)
8941                                         continue;
8942
8943                                 if (c->last_case < l->first_case || c->first_case > l->last_case)
8944                                         continue;
8945
8946                                 errorf(pos, "duplicate case value (previously used %P)",
8947                                        &l->base.source_position);
8948                                 break;
8949                         }
8950                 }
8951                 /* link all cases into the switch statement */
8952                 if (current_switch->last_case == NULL) {
8953                         current_switch->first_case      = &statement->case_label;
8954                 } else {
8955                         current_switch->last_case->next = &statement->case_label;
8956                 }
8957                 current_switch->last_case = &statement->case_label;
8958         } else {
8959                 errorf(pos, "case label not within a switch statement");
8960         }
8961
8962         statement->case_label.statement = parse_label_inner_statement(statement, "case label");
8963
8964         POP_PARENT();
8965         return statement;
8966 }
8967
8968 /**
8969  * Parse a default statement.
8970  */
8971 static statement_t *parse_default_statement(void)
8972 {
8973         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8974
8975         eat(T_default);
8976
8977         PUSH_PARENT(statement);
8978
8979         expect(':');
8980
8981         if (current_switch != NULL) {
8982                 const case_label_statement_t *def_label = current_switch->default_label;
8983                 if (def_label != NULL) {
8984                         errorf(&statement->base.source_position, "multiple default labels in one switch (previous declared %P)", &def_label->base.source_position);
8985                 } else {
8986                         current_switch->default_label = &statement->case_label;
8987
8988                         /* link all cases into the switch statement */
8989                         if (current_switch->last_case == NULL) {
8990                                 current_switch->first_case      = &statement->case_label;
8991                         } else {
8992                                 current_switch->last_case->next = &statement->case_label;
8993                         }
8994                         current_switch->last_case = &statement->case_label;
8995                 }
8996         } else {
8997                 errorf(&statement->base.source_position,
8998                         "'default' label not within a switch statement");
8999         }
9000
9001         statement->case_label.statement = parse_label_inner_statement(statement, "default label");
9002
9003         POP_PARENT();
9004         return statement;
9005 }
9006
9007 /**
9008  * Parse a label statement.
9009  */
9010 static statement_t *parse_label_statement(void)
9011 {
9012         statement_t *const statement = allocate_statement_zero(STATEMENT_LABEL);
9013         label_t     *const label     = get_label(NULL /* Cannot fail, token is T_IDENTIFIER. */);
9014         statement->label.label = label;
9015
9016         PUSH_PARENT(statement);
9017
9018         /* if statement is already set then the label is defined twice,
9019          * otherwise it was just mentioned in a goto/local label declaration so far
9020          */
9021         source_position_t const* const pos = &statement->base.source_position;
9022         if (label->statement != NULL) {
9023                 errorf(pos, "duplicate '%N' (declared %P)", (entity_t const*)label, &label->base.source_position);
9024         } else {
9025                 label->base.source_position = *pos;
9026                 label->statement            = statement;
9027                 label->n_users             += 1;
9028         }
9029
9030         eat(':');
9031
9032         if (token.kind == T___attribute__ && !(c_mode & _CXX)) {
9033                 parse_attributes(NULL); // TODO process attributes
9034         }
9035
9036         statement->label.statement = parse_label_inner_statement(statement, "label");
9037
9038         /* remember the labels in a list for later checking */
9039         *label_anchor = &statement->label;
9040         label_anchor  = &statement->label.next;
9041
9042         POP_PARENT();
9043         return statement;
9044 }
9045
9046 static statement_t *parse_inner_statement(void)
9047 {
9048         statement_t *const stmt = parse_statement();
9049         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
9050         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
9051         if (stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
9052                 errorf(&stmt->base.source_position, "declaration as inner statement, use {}");
9053         }
9054         return stmt;
9055 }
9056
9057 /**
9058  * Parse an expression in parentheses and mark its variables as read.
9059  */
9060 static expression_t *parse_condition(void)
9061 {
9062         add_anchor_token(')');
9063         expect('(');
9064         expression_t *const expr = parse_expression();
9065         mark_vars_read(expr, NULL);
9066         rem_anchor_token(')');
9067         expect(')');
9068         return expr;
9069 }
9070
9071 /**
9072  * Parse an if statement.
9073  */
9074 static statement_t *parse_if(void)
9075 {
9076         statement_t *statement = allocate_statement_zero(STATEMENT_IF);
9077
9078         eat(T_if);
9079
9080         PUSH_PARENT(statement);
9081         PUSH_SCOPE_STATEMENT(&statement->ifs.scope);
9082
9083         add_anchor_token(T_else);
9084
9085         expression_t *const expr = parse_condition();
9086         statement->ifs.condition = expr;
9087         /* §6.8.4.1:1  The controlling expression of an if statement shall have
9088          *             scalar type. */
9089         semantic_condition(expr, "condition of 'if'-statment");
9090
9091         statement_t *const true_stmt = parse_inner_statement();
9092         statement->ifs.true_statement = true_stmt;
9093         rem_anchor_token(T_else);
9094
9095         if (true_stmt->kind == STATEMENT_EMPTY) {
9096                 warningf(WARN_EMPTY_BODY, HERE,
9097                         "suggest braces around empty body in an ‘if’ statement");
9098         }
9099
9100         if (accept(T_else)) {
9101                 statement->ifs.false_statement = parse_inner_statement();
9102
9103                 if (statement->ifs.false_statement->kind == STATEMENT_EMPTY) {
9104                         warningf(WARN_EMPTY_BODY, HERE,
9105                                         "suggest braces around empty body in an ‘if’ statement");
9106                 }
9107         } else if (true_stmt->kind == STATEMENT_IF &&
9108                         true_stmt->ifs.false_statement != NULL) {
9109                 source_position_t const *const pos = &true_stmt->base.source_position;
9110                 warningf(WARN_PARENTHESES, pos, "suggest explicit braces to avoid ambiguous 'else'");
9111         }
9112
9113         POP_SCOPE();
9114         POP_PARENT();
9115         return statement;
9116 }
9117
9118 /**
9119  * Check that all enums are handled in a switch.
9120  *
9121  * @param statement  the switch statement to check
9122  */
9123 static void check_enum_cases(const switch_statement_t *statement)
9124 {
9125         if (!is_warn_on(WARN_SWITCH_ENUM))
9126                 return;
9127         type_t *type = skip_typeref(statement->expression->base.type);
9128         if (! is_type_enum(type))
9129                 return;
9130         enum_type_t *enumt = &type->enumt;
9131
9132         /* if we have a default, no warnings */
9133         if (statement->default_label != NULL)
9134                 return;
9135
9136         determine_enum_values(enumt);
9137
9138         /* FIXME: calculation of value should be done while parsing */
9139         /* TODO: quadratic algorithm here. Change to an n log n one */
9140         const entity_t *entry = enumt->enume->base.next;
9141         for (; entry != NULL && entry->kind == ENTITY_ENUM_VALUE;
9142              entry = entry->base.next) {
9143                 ir_tarval *value = entry->enum_value.tv;
9144                 bool       found = false;
9145                 for (const case_label_statement_t *l = statement->first_case; l != NULL;
9146                      l = l->next) {
9147                         if (l->expression == NULL)
9148                                 continue;
9149                         if (l->first_case == l->last_case && l->first_case != value)
9150                                 continue;
9151                         if ((tarval_cmp(l->first_case, value) & ir_relation_less_equal)
9152                          && (tarval_cmp(value, l->last_case) & ir_relation_less_equal)) {
9153                                 found = true;
9154                                 break;
9155                         }
9156                 }
9157                 if (!found) {
9158                         source_position_t const *const pos = &statement->base.source_position;
9159                         warningf(WARN_SWITCH_ENUM, pos, "'%N' not handled in switch", entry);
9160                 }
9161         }
9162 }
9163
9164 /**
9165  * Parse a switch statement.
9166  */
9167 static statement_t *parse_switch(void)
9168 {
9169         statement_t *statement = allocate_statement_zero(STATEMENT_SWITCH);
9170
9171         eat(T_switch);
9172
9173         PUSH_PARENT(statement);
9174         PUSH_SCOPE_STATEMENT(&statement->switchs.scope);
9175
9176         expression_t *const expr = parse_condition();
9177         type_t       *      type = skip_typeref(expr->base.type);
9178         if (is_type_integer(type)) {
9179                 type = promote_integer(type);
9180                 if (get_akind_rank(get_akind(type)) >= get_akind_rank(ATOMIC_TYPE_LONG)) {
9181                         warningf(WARN_TRADITIONAL, &expr->base.source_position, "'%T' switch expression not converted to '%T' in ISO C", type, type_int);
9182                 }
9183         } else if (is_type_valid(type)) {
9184                 errorf(&expr->base.source_position,
9185                        "switch quantity is not an integer, but '%T'", type);
9186                 type = type_error_type;
9187         }
9188         statement->switchs.expression = create_implicit_cast(expr, type);
9189
9190         switch_statement_t *rem = current_switch;
9191         current_switch          = &statement->switchs;
9192         statement->switchs.body = parse_inner_statement();
9193         current_switch          = rem;
9194
9195         if (statement->switchs.default_label == NULL) {
9196                 warningf(WARN_SWITCH_DEFAULT, &statement->base.source_position, "switch has no default case");
9197         }
9198         check_enum_cases(&statement->switchs);
9199
9200         POP_SCOPE();
9201         POP_PARENT();
9202         return statement;
9203 }
9204
9205 static statement_t *parse_loop_body(statement_t *const loop)
9206 {
9207         statement_t *const rem = current_loop;
9208         current_loop = loop;
9209
9210         statement_t *const body = parse_inner_statement();
9211
9212         current_loop = rem;
9213         return body;
9214 }
9215
9216 /**
9217  * Parse a while statement.
9218  */
9219 static statement_t *parse_while(void)
9220 {
9221         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9222
9223         eat(T_while);
9224
9225         PUSH_PARENT(statement);
9226         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9227
9228         expression_t *const cond = parse_condition();
9229         statement->fors.condition = cond;
9230         /* §6.8.5:2    The controlling expression of an iteration statement shall
9231          *             have scalar type. */
9232         semantic_condition(cond, "condition of 'while'-statement");
9233
9234         statement->fors.body = parse_loop_body(statement);
9235
9236         POP_SCOPE();
9237         POP_PARENT();
9238         return statement;
9239 }
9240
9241 /**
9242  * Parse a do statement.
9243  */
9244 static statement_t *parse_do(void)
9245 {
9246         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
9247
9248         eat(T_do);
9249
9250         PUSH_PARENT(statement);
9251         PUSH_SCOPE_STATEMENT(&statement->do_while.scope);
9252
9253         add_anchor_token(T_while);
9254         statement->do_while.body = parse_loop_body(statement);
9255         rem_anchor_token(T_while);
9256
9257         expect(T_while);
9258         expression_t *const cond = parse_condition();
9259         statement->do_while.condition = cond;
9260         /* §6.8.5:2    The controlling expression of an iteration statement shall
9261          *             have scalar type. */
9262         semantic_condition(cond, "condition of 'do-while'-statement");
9263         expect(';');
9264
9265         POP_SCOPE();
9266         POP_PARENT();
9267         return statement;
9268 }
9269
9270 /**
9271  * Parse a for statement.
9272  */
9273 static statement_t *parse_for(void)
9274 {
9275         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9276
9277         eat(T_for);
9278
9279         PUSH_PARENT(statement);
9280         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9281
9282         add_anchor_token(')');
9283         expect('(');
9284
9285         PUSH_EXTENSION();
9286
9287         if (accept(';')) {
9288         } else if (is_declaration_specifier(&token)) {
9289                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9290         } else {
9291                 add_anchor_token(';');
9292                 expression_t *const init = parse_expression();
9293                 statement->fors.initialisation = init;
9294                 mark_vars_read(init, ENT_ANY);
9295                 if (!expression_has_effect(init)) {
9296                         warningf(WARN_UNUSED_VALUE, &init->base.source_position, "initialisation of 'for'-statement has no effect");
9297                 }
9298                 rem_anchor_token(';');
9299                 expect(';');
9300         }
9301
9302         POP_EXTENSION();
9303
9304         if (token.kind != ';') {
9305                 add_anchor_token(';');
9306                 expression_t *const cond = parse_expression();
9307                 statement->fors.condition = cond;
9308                 /* §6.8.5:2    The controlling expression of an iteration statement
9309                  *             shall have scalar type. */
9310                 semantic_condition(cond, "condition of 'for'-statement");
9311                 mark_vars_read(cond, NULL);
9312                 rem_anchor_token(';');
9313         }
9314         expect(';');
9315         if (token.kind != ')') {
9316                 expression_t *const step = parse_expression();
9317                 statement->fors.step = step;
9318                 mark_vars_read(step, ENT_ANY);
9319                 if (!expression_has_effect(step)) {
9320                         warningf(WARN_UNUSED_VALUE, &step->base.source_position, "step of 'for'-statement has no effect");
9321                 }
9322         }
9323         rem_anchor_token(')');
9324         expect(')');
9325         statement->fors.body = parse_loop_body(statement);
9326
9327         POP_SCOPE();
9328         POP_PARENT();
9329         return statement;
9330 }
9331
9332 /**
9333  * Parse a goto statement.
9334  */
9335 static statement_t *parse_goto(void)
9336 {
9337         statement_t *statement;
9338         if (GNU_MODE && look_ahead(1)->kind == '*') {
9339                 statement = allocate_statement_zero(STATEMENT_COMPUTED_GOTO);
9340                 eat(T_goto);
9341                 eat('*');
9342
9343                 expression_t *expression = parse_expression();
9344                 mark_vars_read(expression, NULL);
9345
9346                 /* Argh: although documentation says the expression must be of type void*,
9347                  * gcc accepts anything that can be casted into void* without error */
9348                 type_t *type = expression->base.type;
9349
9350                 if (type != type_error_type) {
9351                         if (!is_type_pointer(type) && !is_type_integer(type)) {
9352                                 errorf(&expression->base.source_position,
9353                                         "cannot convert to a pointer type");
9354                         } else if (type != type_void_ptr) {
9355                                 warningf(WARN_OTHER, &expression->base.source_position, "type of computed goto expression should be 'void*' not '%T'", type);
9356                         }
9357                         expression = create_implicit_cast(expression, type_void_ptr);
9358                 }
9359
9360                 statement->computed_goto.expression = expression;
9361         } else {
9362                 statement = allocate_statement_zero(STATEMENT_GOTO);
9363                 eat(T_goto);
9364
9365                 label_t *const label = get_label("while parsing goto");
9366                 if (label) {
9367                         label->n_users        += 1;
9368                         label->used            = true;
9369                         statement->gotos.label = label;
9370
9371                         /* remember the goto's in a list for later checking */
9372                         *goto_anchor = &statement->gotos;
9373                         goto_anchor  = &statement->gotos.next;
9374                 } else {
9375                         statement->gotos.label = &allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym_anonymous, &builtin_source_position)->label;
9376                 }
9377         }
9378
9379         expect(';');
9380         return statement;
9381 }
9382
9383 /**
9384  * Parse a continue statement.
9385  */
9386 static statement_t *parse_continue(void)
9387 {
9388         if (current_loop == NULL) {
9389                 errorf(HERE, "continue statement not within loop");
9390         }
9391
9392         statement_t *statement = allocate_statement_zero(STATEMENT_CONTINUE);
9393
9394         eat(T_continue);
9395         expect(';');
9396         return statement;
9397 }
9398
9399 /**
9400  * Parse a break statement.
9401  */
9402 static statement_t *parse_break(void)
9403 {
9404         if (current_switch == NULL && current_loop == NULL) {
9405                 errorf(HERE, "break statement not within loop or switch");
9406         }
9407
9408         statement_t *statement = allocate_statement_zero(STATEMENT_BREAK);
9409
9410         eat(T_break);
9411         expect(';');
9412         return statement;
9413 }
9414
9415 /**
9416  * Parse a __leave statement.
9417  */
9418 static statement_t *parse_leave_statement(void)
9419 {
9420         if (current_try == NULL) {
9421                 errorf(HERE, "__leave statement not within __try");
9422         }
9423
9424         statement_t *statement = allocate_statement_zero(STATEMENT_LEAVE);
9425
9426         eat(T___leave);
9427         expect(';');
9428         return statement;
9429 }
9430
9431 /**
9432  * Check if a given entity represents a local variable.
9433  */
9434 static bool is_local_variable(const entity_t *entity)
9435 {
9436         if (entity->kind != ENTITY_VARIABLE)
9437                 return false;
9438
9439         switch ((storage_class_tag_t) entity->declaration.storage_class) {
9440         case STORAGE_CLASS_AUTO:
9441         case STORAGE_CLASS_REGISTER: {
9442                 const type_t *type = skip_typeref(entity->declaration.type);
9443                 if (is_type_function(type)) {
9444                         return false;
9445                 } else {
9446                         return true;
9447                 }
9448         }
9449         default:
9450                 return false;
9451         }
9452 }
9453
9454 /**
9455  * Check if a given expression represents a local variable.
9456  */
9457 static bool expression_is_local_variable(const expression_t *expression)
9458 {
9459         if (expression->base.kind != EXPR_REFERENCE) {
9460                 return false;
9461         }
9462         const entity_t *entity = expression->reference.entity;
9463         return is_local_variable(entity);
9464 }
9465
9466 static void err_or_warn(source_position_t const *const pos, char const *const msg)
9467 {
9468         if (c_mode & _CXX || strict_mode) {
9469                 errorf(pos, msg);
9470         } else {
9471                 warningf(WARN_OTHER, pos, msg);
9472         }
9473 }
9474
9475 /**
9476  * Parse a return statement.
9477  */
9478 static statement_t *parse_return(void)
9479 {
9480         statement_t *statement = allocate_statement_zero(STATEMENT_RETURN);
9481         eat(T_return);
9482
9483         expression_t *return_value = NULL;
9484         if (token.kind != ';') {
9485                 return_value = parse_expression();
9486                 mark_vars_read(return_value, NULL);
9487         }
9488
9489         const type_t *const func_type = skip_typeref(current_function->base.type);
9490         assert(is_type_function(func_type));
9491         type_t *const return_type = skip_typeref(func_type->function.return_type);
9492
9493         source_position_t const *const pos = &statement->base.source_position;
9494         if (return_value != NULL) {
9495                 type_t *return_value_type = skip_typeref(return_value->base.type);
9496
9497                 if (is_type_void(return_type)) {
9498                         if (!is_type_void(return_value_type)) {
9499                                 /* ISO/IEC 14882:1998(E) §6.6.3:2 */
9500                                 /* Only warn in C mode, because GCC does the same */
9501                                 err_or_warn(pos, "'return' with a value, in function returning 'void'");
9502                         } else if (!(c_mode & _CXX)) { /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9503                                 /* Only warn in C mode, because GCC does the same */
9504                                 err_or_warn(pos, "'return' with expression in function returning 'void'");
9505                         }
9506                 } else {
9507                         assign_error_t error = semantic_assign(return_type, return_value);
9508                         report_assign_error(error, return_type, return_value, "'return'",
9509                                             pos);
9510                 }
9511                 return_value = create_implicit_cast(return_value, return_type);
9512                 /* check for returning address of a local var */
9513                 if (return_value != NULL && return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
9514                         const expression_t *expression = return_value->unary.value;
9515                         if (expression_is_local_variable(expression)) {
9516                                 warningf(WARN_OTHER, pos, "function returns address of local variable");
9517                         }
9518                 }
9519         } else if (!is_type_void(return_type)) {
9520                 /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9521                 err_or_warn(pos, "'return' without value, in function returning non-void");
9522         }
9523         statement->returns.value = return_value;
9524
9525         expect(';');
9526         return statement;
9527 }
9528
9529 /**
9530  * Parse a declaration statement.
9531  */
9532 static statement_t *parse_declaration_statement(void)
9533 {
9534         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9535
9536         entity_t *before = current_scope->last_entity;
9537         if (GNU_MODE) {
9538                 parse_external_declaration();
9539         } else {
9540                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9541         }
9542
9543         declaration_statement_t *const decl  = &statement->declaration;
9544         entity_t                *const begin =
9545                 before != NULL ? before->base.next : current_scope->entities;
9546         decl->declarations_begin = begin;
9547         decl->declarations_end   = begin != NULL ? current_scope->last_entity : NULL;
9548
9549         return statement;
9550 }
9551
9552 /**
9553  * Parse an expression statement, ie. expr ';'.
9554  */
9555 static statement_t *parse_expression_statement(void)
9556 {
9557         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
9558
9559         expression_t *const expr         = parse_expression();
9560         statement->expression.expression = expr;
9561         mark_vars_read(expr, ENT_ANY);
9562
9563         expect(';');
9564         return statement;
9565 }
9566
9567 /**
9568  * Parse a microsoft __try { } __finally { } or
9569  * __try{ } __except() { }
9570  */
9571 static statement_t *parse_ms_try_statment(void)
9572 {
9573         statement_t *statement = allocate_statement_zero(STATEMENT_MS_TRY);
9574         eat(T___try);
9575
9576         PUSH_PARENT(statement);
9577
9578         ms_try_statement_t *rem = current_try;
9579         current_try = &statement->ms_try;
9580         statement->ms_try.try_statement = parse_compound_statement(false);
9581         current_try = rem;
9582
9583         POP_PARENT();
9584
9585         if (accept(T___except)) {
9586                 expression_t *const expr = parse_condition();
9587                 type_t       *      type = skip_typeref(expr->base.type);
9588                 if (is_type_integer(type)) {
9589                         type = promote_integer(type);
9590                 } else if (is_type_valid(type)) {
9591                         errorf(&expr->base.source_position,
9592                                "__expect expression is not an integer, but '%T'", type);
9593                         type = type_error_type;
9594                 }
9595                 statement->ms_try.except_expression = create_implicit_cast(expr, type);
9596         } else if (!accept(T__finally)) {
9597                 parse_error_expected("while parsing __try statement", T___except, T___finally, NULL);
9598         }
9599         statement->ms_try.final_statement = parse_compound_statement(false);
9600         return statement;
9601 }
9602
9603 static statement_t *parse_empty_statement(void)
9604 {
9605         warningf(WARN_EMPTY_STATEMENT, HERE, "statement is empty");
9606         statement_t *const statement = create_empty_statement();
9607         eat(';');
9608         return statement;
9609 }
9610
9611 static statement_t *parse_local_label_declaration(void)
9612 {
9613         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9614
9615         eat(T___label__);
9616
9617         entity_t *begin   = NULL;
9618         entity_t *end     = NULL;
9619         entity_t **anchor = &begin;
9620         add_anchor_token(';');
9621         add_anchor_token(',');
9622         do {
9623                 source_position_t pos;
9624                 symbol_t *const symbol = expect_identifier("while parsing local label declaration", &pos);
9625                 if (symbol) {
9626                         entity_t *entity = get_entity(symbol, NAMESPACE_LABEL);
9627                         if (entity != NULL && entity->base.parent_scope == current_scope) {
9628                                 source_position_t const *const ppos = &entity->base.source_position;
9629                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
9630                         } else {
9631                                 entity = allocate_entity_zero(ENTITY_LOCAL_LABEL, NAMESPACE_LABEL, symbol, &pos);
9632                                 entity->base.parent_scope = current_scope;
9633
9634                                 *anchor = entity;
9635                                 anchor  = &entity->base.next;
9636                                 end     = entity;
9637
9638                                 environment_push(entity);
9639                         }
9640                 }
9641         } while (accept(','));
9642         rem_anchor_token(',');
9643         rem_anchor_token(';');
9644         expect(';');
9645         statement->declaration.declarations_begin = begin;
9646         statement->declaration.declarations_end   = end;
9647         return statement;
9648 }
9649
9650 static void parse_namespace_definition(void)
9651 {
9652         eat(T_namespace);
9653
9654         entity_t *entity = NULL;
9655         symbol_t *symbol = NULL;
9656
9657         if (token.kind == T_IDENTIFIER) {
9658                 symbol = token.base.symbol;
9659                 entity = get_entity(symbol, NAMESPACE_NORMAL);
9660                 if (entity && entity->kind != ENTITY_NAMESPACE) {
9661                         entity = NULL;
9662                         if (entity->base.parent_scope == current_scope && is_entity_valid(entity)) {
9663                                 error_redefined_as_different_kind(HERE, entity, ENTITY_NAMESPACE);
9664                         }
9665                 }
9666                 eat(T_IDENTIFIER);
9667         }
9668
9669         if (entity == NULL) {
9670                 entity = allocate_entity_zero(ENTITY_NAMESPACE, NAMESPACE_NORMAL, symbol, HERE);
9671                 entity->base.parent_scope = current_scope;
9672         }
9673
9674         if (token.kind == '=') {
9675                 /* TODO: parse namespace alias */
9676                 panic("namespace alias definition not supported yet");
9677         }
9678
9679         environment_push(entity);
9680         append_entity(current_scope, entity);
9681
9682         PUSH_SCOPE(&entity->namespacee.members);
9683         PUSH_CURRENT_ENTITY(entity);
9684
9685         add_anchor_token('}');
9686         expect('{');
9687         parse_externals();
9688         rem_anchor_token('}');
9689         expect('}');
9690
9691         POP_CURRENT_ENTITY();
9692         POP_SCOPE();
9693 }
9694
9695 /**
9696  * Parse a statement.
9697  * There's also parse_statement() which additionally checks for
9698  * "statement has no effect" warnings
9699  */
9700 static statement_t *intern_parse_statement(void)
9701 {
9702         /* declaration or statement */
9703         statement_t *statement;
9704         switch (token.kind) {
9705         case T_IDENTIFIER: {
9706                 token_kind_t la1_type = (token_kind_t)look_ahead(1)->kind;
9707                 if (la1_type == ':') {
9708                         statement = parse_label_statement();
9709                 } else if (is_typedef_symbol(token.base.symbol)) {
9710                         statement = parse_declaration_statement();
9711                 } else {
9712                         /* it's an identifier, the grammar says this must be an
9713                          * expression statement. However it is common that users mistype
9714                          * declaration types, so we guess a bit here to improve robustness
9715                          * for incorrect programs */
9716                         switch (la1_type) {
9717                         case '&':
9718                         case '*':
9719                                 if (get_entity(token.base.symbol, NAMESPACE_NORMAL) != NULL) {
9720                         default:
9721                                         statement = parse_expression_statement();
9722                                 } else {
9723                         DECLARATION_START
9724                         case T_IDENTIFIER:
9725                                         statement = parse_declaration_statement();
9726                                 }
9727                                 break;
9728                         }
9729                 }
9730                 break;
9731         }
9732
9733         case T___extension__: {
9734                 /* This can be a prefix to a declaration or an expression statement.
9735                  * We simply eat it now and parse the rest with tail recursion. */
9736                 PUSH_EXTENSION();
9737                 statement = intern_parse_statement();
9738                 POP_EXTENSION();
9739                 break;
9740         }
9741
9742         DECLARATION_START
9743                 statement = parse_declaration_statement();
9744                 break;
9745
9746         case T___label__:
9747                 statement = parse_local_label_declaration();
9748                 break;
9749
9750         case ';':         statement = parse_empty_statement();         break;
9751         case '{':         statement = parse_compound_statement(false); break;
9752         case T___leave:   statement = parse_leave_statement();         break;
9753         case T___try:     statement = parse_ms_try_statment();         break;
9754         case T_asm:       statement = parse_asm_statement();           break;
9755         case T_break:     statement = parse_break();                   break;
9756         case T_case:      statement = parse_case_statement();          break;
9757         case T_continue:  statement = parse_continue();                break;
9758         case T_default:   statement = parse_default_statement();       break;
9759         case T_do:        statement = parse_do();                      break;
9760         case T_for:       statement = parse_for();                     break;
9761         case T_goto:      statement = parse_goto();                    break;
9762         case T_if:        statement = parse_if();                      break;
9763         case T_return:    statement = parse_return();                  break;
9764         case T_switch:    statement = parse_switch();                  break;
9765         case T_while:     statement = parse_while();                   break;
9766
9767         EXPRESSION_START
9768                 statement = parse_expression_statement();
9769                 break;
9770
9771         default:
9772                 errorf(HERE, "unexpected token %K while parsing statement", &token);
9773                 statement = create_error_statement();
9774                 eat_until_anchor();
9775                 break;
9776         }
9777
9778         return statement;
9779 }
9780
9781 /**
9782  * parse a statement and emits "statement has no effect" warning if needed
9783  * (This is really a wrapper around intern_parse_statement with check for 1
9784  *  single warning. It is needed, because for statement expressions we have
9785  *  to avoid the warning on the last statement)
9786  */
9787 static statement_t *parse_statement(void)
9788 {
9789         statement_t *statement = intern_parse_statement();
9790
9791         if (statement->kind == STATEMENT_EXPRESSION) {
9792                 expression_t *expression = statement->expression.expression;
9793                 if (!expression_has_effect(expression)) {
9794                         warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9795                 }
9796         }
9797
9798         return statement;
9799 }
9800
9801 /**
9802  * Parse a compound statement.
9803  */
9804 static statement_t *parse_compound_statement(bool inside_expression_statement)
9805 {
9806         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
9807
9808         PUSH_PARENT(statement);
9809         PUSH_SCOPE(&statement->compound.scope);
9810
9811         eat('{');
9812         add_anchor_token('}');
9813         /* tokens, which can start a statement */
9814         /* TODO MS, __builtin_FOO */
9815         add_anchor_token('!');
9816         add_anchor_token('&');
9817         add_anchor_token('(');
9818         add_anchor_token('*');
9819         add_anchor_token('+');
9820         add_anchor_token('-');
9821         add_anchor_token(';');
9822         add_anchor_token('{');
9823         add_anchor_token('~');
9824         add_anchor_token(T_CHARACTER_CONSTANT);
9825         add_anchor_token(T_COLONCOLON);
9826         add_anchor_token(T_IDENTIFIER);
9827         add_anchor_token(T_MINUSMINUS);
9828         add_anchor_token(T_NUMBER);
9829         add_anchor_token(T_PLUSPLUS);
9830         add_anchor_token(T_STRING_LITERAL);
9831         add_anchor_token(T__Alignof);
9832         add_anchor_token(T__Bool);
9833         add_anchor_token(T__Complex);
9834         add_anchor_token(T__Imaginary);
9835         add_anchor_token(T__Thread_local);
9836         add_anchor_token(T___PRETTY_FUNCTION__);
9837         add_anchor_token(T___attribute__);
9838         add_anchor_token(T___builtin_va_start);
9839         add_anchor_token(T___extension__);
9840         add_anchor_token(T___func__);
9841         add_anchor_token(T___imag__);
9842         add_anchor_token(T___label__);
9843         add_anchor_token(T___real__);
9844         add_anchor_token(T_asm);
9845         add_anchor_token(T_auto);
9846         add_anchor_token(T_bool);
9847         add_anchor_token(T_break);
9848         add_anchor_token(T_case);
9849         add_anchor_token(T_char);
9850         add_anchor_token(T_class);
9851         add_anchor_token(T_const);
9852         add_anchor_token(T_const_cast);
9853         add_anchor_token(T_continue);
9854         add_anchor_token(T_default);
9855         add_anchor_token(T_delete);
9856         add_anchor_token(T_double);
9857         add_anchor_token(T_do);
9858         add_anchor_token(T_dynamic_cast);
9859         add_anchor_token(T_enum);
9860         add_anchor_token(T_extern);
9861         add_anchor_token(T_false);
9862         add_anchor_token(T_float);
9863         add_anchor_token(T_for);
9864         add_anchor_token(T_goto);
9865         add_anchor_token(T_if);
9866         add_anchor_token(T_inline);
9867         add_anchor_token(T_int);
9868         add_anchor_token(T_long);
9869         add_anchor_token(T_new);
9870         add_anchor_token(T_operator);
9871         add_anchor_token(T_register);
9872         add_anchor_token(T_reinterpret_cast);
9873         add_anchor_token(T_restrict);
9874         add_anchor_token(T_return);
9875         add_anchor_token(T_short);
9876         add_anchor_token(T_signed);
9877         add_anchor_token(T_sizeof);
9878         add_anchor_token(T_static);
9879         add_anchor_token(T_static_cast);
9880         add_anchor_token(T_struct);
9881         add_anchor_token(T_switch);
9882         add_anchor_token(T_template);
9883         add_anchor_token(T_this);
9884         add_anchor_token(T_throw);
9885         add_anchor_token(T_true);
9886         add_anchor_token(T_try);
9887         add_anchor_token(T_typedef);
9888         add_anchor_token(T_typeid);
9889         add_anchor_token(T_typename);
9890         add_anchor_token(T_typeof);
9891         add_anchor_token(T_union);
9892         add_anchor_token(T_unsigned);
9893         add_anchor_token(T_using);
9894         add_anchor_token(T_void);
9895         add_anchor_token(T_volatile);
9896         add_anchor_token(T_wchar_t);
9897         add_anchor_token(T_while);
9898
9899         statement_t **anchor            = &statement->compound.statements;
9900         bool          only_decls_so_far = true;
9901         while (token.kind != '}' && token.kind != T_EOF) {
9902                 statement_t *sub_statement = intern_parse_statement();
9903                 if (sub_statement->kind == STATEMENT_ERROR) {
9904                         break;
9905                 }
9906
9907                 if (sub_statement->kind != STATEMENT_DECLARATION) {
9908                         only_decls_so_far = false;
9909                 } else if (!only_decls_so_far) {
9910                         source_position_t const *const pos = &sub_statement->base.source_position;
9911                         warningf(WARN_DECLARATION_AFTER_STATEMENT, pos, "ISO C90 forbids mixed declarations and code");
9912                 }
9913
9914                 *anchor = sub_statement;
9915                 anchor  = &sub_statement->base.next;
9916         }
9917         expect('}');
9918
9919         /* look over all statements again to produce no effect warnings */
9920         if (is_warn_on(WARN_UNUSED_VALUE)) {
9921                 statement_t *sub_statement = statement->compound.statements;
9922                 for (; sub_statement != NULL; sub_statement = sub_statement->base.next) {
9923                         if (sub_statement->kind != STATEMENT_EXPRESSION)
9924                                 continue;
9925                         /* don't emit a warning for the last expression in an expression
9926                          * statement as it has always an effect */
9927                         if (inside_expression_statement && sub_statement->base.next == NULL)
9928                                 continue;
9929
9930                         expression_t *expression = sub_statement->expression.expression;
9931                         if (!expression_has_effect(expression)) {
9932                                 warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9933                         }
9934                 }
9935         }
9936
9937         rem_anchor_token(T_while);
9938         rem_anchor_token(T_wchar_t);
9939         rem_anchor_token(T_volatile);
9940         rem_anchor_token(T_void);
9941         rem_anchor_token(T_using);
9942         rem_anchor_token(T_unsigned);
9943         rem_anchor_token(T_union);
9944         rem_anchor_token(T_typeof);
9945         rem_anchor_token(T_typename);
9946         rem_anchor_token(T_typeid);
9947         rem_anchor_token(T_typedef);
9948         rem_anchor_token(T_try);
9949         rem_anchor_token(T_true);
9950         rem_anchor_token(T_throw);
9951         rem_anchor_token(T_this);
9952         rem_anchor_token(T_template);
9953         rem_anchor_token(T_switch);
9954         rem_anchor_token(T_struct);
9955         rem_anchor_token(T_static_cast);
9956         rem_anchor_token(T_static);
9957         rem_anchor_token(T_sizeof);
9958         rem_anchor_token(T_signed);
9959         rem_anchor_token(T_short);
9960         rem_anchor_token(T_return);
9961         rem_anchor_token(T_restrict);
9962         rem_anchor_token(T_reinterpret_cast);
9963         rem_anchor_token(T_register);
9964         rem_anchor_token(T_operator);
9965         rem_anchor_token(T_new);
9966         rem_anchor_token(T_long);
9967         rem_anchor_token(T_int);
9968         rem_anchor_token(T_inline);
9969         rem_anchor_token(T_if);
9970         rem_anchor_token(T_goto);
9971         rem_anchor_token(T_for);
9972         rem_anchor_token(T_float);
9973         rem_anchor_token(T_false);
9974         rem_anchor_token(T_extern);
9975         rem_anchor_token(T_enum);
9976         rem_anchor_token(T_dynamic_cast);
9977         rem_anchor_token(T_do);
9978         rem_anchor_token(T_double);
9979         rem_anchor_token(T_delete);
9980         rem_anchor_token(T_default);
9981         rem_anchor_token(T_continue);
9982         rem_anchor_token(T_const_cast);
9983         rem_anchor_token(T_const);
9984         rem_anchor_token(T_class);
9985         rem_anchor_token(T_char);
9986         rem_anchor_token(T_case);
9987         rem_anchor_token(T_break);
9988         rem_anchor_token(T_bool);
9989         rem_anchor_token(T_auto);
9990         rem_anchor_token(T_asm);
9991         rem_anchor_token(T___real__);
9992         rem_anchor_token(T___label__);
9993         rem_anchor_token(T___imag__);
9994         rem_anchor_token(T___func__);
9995         rem_anchor_token(T___extension__);
9996         rem_anchor_token(T___builtin_va_start);
9997         rem_anchor_token(T___attribute__);
9998         rem_anchor_token(T___PRETTY_FUNCTION__);
9999         rem_anchor_token(T__Thread_local);
10000         rem_anchor_token(T__Imaginary);
10001         rem_anchor_token(T__Complex);
10002         rem_anchor_token(T__Bool);
10003         rem_anchor_token(T__Alignof);
10004         rem_anchor_token(T_STRING_LITERAL);
10005         rem_anchor_token(T_PLUSPLUS);
10006         rem_anchor_token(T_NUMBER);
10007         rem_anchor_token(T_MINUSMINUS);
10008         rem_anchor_token(T_IDENTIFIER);
10009         rem_anchor_token(T_COLONCOLON);
10010         rem_anchor_token(T_CHARACTER_CONSTANT);
10011         rem_anchor_token('~');
10012         rem_anchor_token('{');
10013         rem_anchor_token(';');
10014         rem_anchor_token('-');
10015         rem_anchor_token('+');
10016         rem_anchor_token('*');
10017         rem_anchor_token('(');
10018         rem_anchor_token('&');
10019         rem_anchor_token('!');
10020         rem_anchor_token('}');
10021
10022         POP_SCOPE();
10023         POP_PARENT();
10024         return statement;
10025 }
10026
10027 /**
10028  * Check for unused global static functions and variables
10029  */
10030 static void check_unused_globals(void)
10031 {
10032         if (!is_warn_on(WARN_UNUSED_FUNCTION) && !is_warn_on(WARN_UNUSED_VARIABLE))
10033                 return;
10034
10035         for (const entity_t *entity = file_scope->entities; entity != NULL;
10036              entity = entity->base.next) {
10037                 if (!is_declaration(entity))
10038                         continue;
10039
10040                 const declaration_t *declaration = &entity->declaration;
10041                 if (declaration->used                  ||
10042                     declaration->modifiers & DM_UNUSED ||
10043                     declaration->modifiers & DM_USED   ||
10044                     declaration->storage_class != STORAGE_CLASS_STATIC)
10045                         continue;
10046
10047                 warning_t   why;
10048                 char const *s;
10049                 if (entity->kind == ENTITY_FUNCTION) {
10050                         /* inhibit warning for static inline functions */
10051                         if (entity->function.is_inline)
10052                                 continue;
10053
10054                         why = WARN_UNUSED_FUNCTION;
10055                         s   = entity->function.body != NULL ? "defined" : "declared";
10056                 } else {
10057                         why = WARN_UNUSED_VARIABLE;
10058                         s   = "defined";
10059                 }
10060
10061                 warningf(why, &declaration->base.source_position, "'%#N' %s but not used", entity, s);
10062         }
10063 }
10064
10065 static void parse_global_asm(void)
10066 {
10067         statement_t *statement = allocate_statement_zero(STATEMENT_ASM);
10068
10069         eat(T_asm);
10070         add_anchor_token(';');
10071         add_anchor_token(')');
10072         add_anchor_token(T_STRING_LITERAL);
10073         expect('(');
10074
10075         rem_anchor_token(T_STRING_LITERAL);
10076         statement->asms.asm_text = parse_string_literals("global asm");
10077         statement->base.next     = unit->global_asm;
10078         unit->global_asm         = statement;
10079
10080         rem_anchor_token(')');
10081         expect(')');
10082         rem_anchor_token(';');
10083         expect(';');
10084 }
10085
10086 static void parse_linkage_specification(void)
10087 {
10088         eat(T_extern);
10089
10090         source_position_t const pos     = *HERE;
10091         char const       *const linkage = parse_string_literals(NULL).begin;
10092
10093         linkage_kind_t old_linkage = current_linkage;
10094         linkage_kind_t new_linkage;
10095         if (streq(linkage, "C")) {
10096                 new_linkage = LINKAGE_C;
10097         } else if (streq(linkage, "C++")) {
10098                 new_linkage = LINKAGE_CXX;
10099         } else {
10100                 errorf(&pos, "linkage string \"%s\" not recognized", linkage);
10101                 new_linkage = LINKAGE_C;
10102         }
10103         current_linkage = new_linkage;
10104
10105         if (accept('{')) {
10106                 parse_externals();
10107                 expect('}');
10108         } else {
10109                 parse_external();
10110         }
10111
10112         assert(current_linkage == new_linkage);
10113         current_linkage = old_linkage;
10114 }
10115
10116 static void parse_external(void)
10117 {
10118         switch (token.kind) {
10119                 case T_extern:
10120                         if (look_ahead(1)->kind == T_STRING_LITERAL) {
10121                                 parse_linkage_specification();
10122                         } else {
10123                 DECLARATION_START_NO_EXTERN
10124                 case T_IDENTIFIER:
10125                 case T___extension__:
10126                 /* tokens below are for implicit int */
10127                 case '&':  /* & x; -> int& x; (and error later, because C++ has no
10128                               implicit int) */
10129                 case '*':  /* * x; -> int* x; */
10130                 case '(':  /* (x); -> int (x); */
10131                                 PUSH_EXTENSION();
10132                                 parse_external_declaration();
10133                                 POP_EXTENSION();
10134                         }
10135                         return;
10136
10137                 case T_asm:
10138                         parse_global_asm();
10139                         return;
10140
10141                 case T_namespace:
10142                         parse_namespace_definition();
10143                         return;
10144
10145                 case ';':
10146                         if (!strict_mode) {
10147                                 warningf(WARN_STRAY_SEMICOLON, HERE, "stray ';' outside of function");
10148                                 eat(';');
10149                                 return;
10150                         }
10151                         /* FALLTHROUGH */
10152
10153                 default:
10154                         errorf(HERE, "stray %K outside of function", &token);
10155                         if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10156                                 eat_until_matching_token(token.kind);
10157                         next_token();
10158                         return;
10159         }
10160 }
10161
10162 static void parse_externals(void)
10163 {
10164         add_anchor_token('}');
10165         add_anchor_token(T_EOF);
10166
10167 #ifndef NDEBUG
10168         /* make a copy of the anchor set, so we can check if it is restored after parsing */
10169         unsigned short token_anchor_copy[T_LAST_TOKEN];
10170         memcpy(token_anchor_copy, token_anchor_set, sizeof(token_anchor_copy));
10171 #endif
10172
10173         while (token.kind != T_EOF && token.kind != '}') {
10174 #ifndef NDEBUG
10175                 for (int i = 0; i < T_LAST_TOKEN; ++i) {
10176                         unsigned short count = token_anchor_set[i] - token_anchor_copy[i];
10177                         if (count != 0) {
10178                                 /* the anchor set and its copy differs */
10179                                 internal_errorf(HERE, "Leaked anchor token %k %d times", i, count);
10180                         }
10181                 }
10182                 if (in_gcc_extension) {
10183                         /* an gcc extension scope was not closed */
10184                         internal_errorf(HERE, "Leaked __extension__");
10185                 }
10186 #endif
10187
10188                 parse_external();
10189         }
10190
10191         rem_anchor_token(T_EOF);
10192         rem_anchor_token('}');
10193 }
10194
10195 /**
10196  * Parse a translation unit.
10197  */
10198 static void parse_translation_unit(void)
10199 {
10200         add_anchor_token(T_EOF);
10201
10202         while (true) {
10203                 parse_externals();
10204
10205                 if (token.kind == T_EOF)
10206                         break;
10207
10208                 errorf(HERE, "stray %K outside of function", &token);
10209                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10210                         eat_until_matching_token(token.kind);
10211                 next_token();
10212         }
10213 }
10214
10215 void set_default_visibility(elf_visibility_tag_t visibility)
10216 {
10217         default_visibility = visibility;
10218 }
10219
10220 /**
10221  * Parse the input.
10222  *
10223  * @return  the translation unit or NULL if errors occurred.
10224  */
10225 void start_parsing(void)
10226 {
10227         environment_stack = NEW_ARR_F(stack_entry_t, 0);
10228         label_stack       = NEW_ARR_F(stack_entry_t, 0);
10229
10230         print_to_file(stderr);
10231
10232         assert(unit == NULL);
10233         unit = allocate_ast_zero(sizeof(unit[0]));
10234
10235         assert(file_scope == NULL);
10236         file_scope = &unit->scope;
10237
10238         assert(current_scope == NULL);
10239         scope_push(&unit->scope);
10240
10241         create_gnu_builtins();
10242         if (c_mode & _MS)
10243                 create_microsoft_intrinsics();
10244 }
10245
10246 translation_unit_t *finish_parsing(void)
10247 {
10248         assert(current_scope == &unit->scope);
10249         scope_pop(NULL);
10250
10251         assert(file_scope == &unit->scope);
10252         check_unused_globals();
10253         file_scope = NULL;
10254
10255         DEL_ARR_F(environment_stack);
10256         DEL_ARR_F(label_stack);
10257
10258         translation_unit_t *result = unit;
10259         unit = NULL;
10260         return result;
10261 }
10262
10263 /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
10264  * are given length one. */
10265 static void complete_incomplete_arrays(void)
10266 {
10267         size_t n = ARR_LEN(incomplete_arrays);
10268         for (size_t i = 0; i != n; ++i) {
10269                 declaration_t *const decl = incomplete_arrays[i];
10270                 type_t        *const type = skip_typeref(decl->type);
10271
10272                 if (!is_type_incomplete(type))
10273                         continue;
10274
10275                 source_position_t const *const pos = &decl->base.source_position;
10276                 warningf(WARN_OTHER, pos, "array '%#N' assumed to have one element", (entity_t const*)decl);
10277
10278                 type_t *const new_type = duplicate_type(type);
10279                 new_type->array.size_constant     = true;
10280                 new_type->array.has_implicit_size = true;
10281                 new_type->array.size              = 1;
10282
10283                 type_t *const result = identify_new_type(new_type);
10284
10285                 decl->type = result;
10286         }
10287 }
10288
10289 static void prepare_main_collect2(entity_t *const entity)
10290 {
10291         PUSH_SCOPE(&entity->function.body->compound.scope);
10292
10293         // create call to __main
10294         symbol_t *symbol         = symbol_table_insert("__main");
10295         entity_t *subsubmain_ent
10296                 = create_implicit_function(symbol, &builtin_source_position);
10297
10298         expression_t *ref         = allocate_expression_zero(EXPR_REFERENCE);
10299         type_t       *ftype       = subsubmain_ent->declaration.type;
10300         ref->base.source_position = builtin_source_position;
10301         ref->base.type            = make_pointer_type(ftype, TYPE_QUALIFIER_NONE);
10302         ref->reference.entity     = subsubmain_ent;
10303
10304         expression_t *call = allocate_expression_zero(EXPR_CALL);
10305         call->base.source_position = builtin_source_position;
10306         call->base.type            = type_void;
10307         call->call.function        = ref;
10308
10309         statement_t *expr_statement = allocate_statement_zero(STATEMENT_EXPRESSION);
10310         expr_statement->base.source_position  = builtin_source_position;
10311         expr_statement->expression.expression = call;
10312
10313         statement_t *const body = entity->function.body;
10314         assert(body->kind == STATEMENT_COMPOUND);
10315         compound_statement_t *compounds = &body->compound;
10316
10317         expr_statement->base.next = compounds->statements;
10318         compounds->statements     = expr_statement;
10319
10320         POP_SCOPE();
10321 }
10322
10323 void parse(void)
10324 {
10325         lookahead_bufpos = 0;
10326         for (int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
10327                 next_token();
10328         }
10329         current_linkage   = c_mode & _CXX ? LINKAGE_CXX : LINKAGE_C;
10330         incomplete_arrays = NEW_ARR_F(declaration_t*, 0);
10331         parse_translation_unit();
10332         complete_incomplete_arrays();
10333         DEL_ARR_F(incomplete_arrays);
10334         incomplete_arrays = NULL;
10335 }
10336
10337 /**
10338  * Initialize the parser.
10339  */
10340 void init_parser(void)
10341 {
10342         memset(token_anchor_set, 0, sizeof(token_anchor_set));
10343
10344         init_expression_parsers();
10345         obstack_init(&temp_obst);
10346 }
10347
10348 /**
10349  * Terminate the parser.
10350  */
10351 void exit_parser(void)
10352 {
10353         obstack_free(&temp_obst, NULL);
10354 }