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