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 <stdarg.h>
  24 #include <stdbool.h>
  25
  26 #include "adt/strutil.h"
  27 #include "parser.h"
  28 #include "diagnostic.h"
  29 #include "format_check.h"
  30 #include "lexer.h"
  31 #include "symbol_t.h"
  32 #include "token_t.h"
  33 #include "types.h"
  34 #include "type_t.h"
  35 #include "type_hash.h"
  36 #include "ast_t.h"
  37 #include "entity_t.h"
  38 #include "attribute_t.h"
  39 #include "lang_features.h"
  40 #include "walk.h"
  41 #include "warning.h"
  42 #include "printer.h"
  43 #include "adt/bitfiddle.h"
  44 #include "adt/error.h"
  45 #include "adt/array.h"
  46
  47 //#define PRINT_TOKENS
  48 #define MAX_LOOKAHEAD 1
  49
  50 typedef struct {
  51         entity_t           *old_entity;
  52         symbol_t           *symbol;
  53         entity_namespace_t  namespc;
  54 } stack_entry_t;
  55
  56 typedef struct declaration_specifiers_t  declaration_specifiers_t;
  57 struct declaration_specifiers_t {
  58         source_position_t  source_position;
  59         storage_class_t    storage_class;
  60         unsigned char      alignment;         /**< Alignment, 0 if not set. */
  61         bool               is_inline    : 1;
  62         bool               thread_local : 1;  /**< GCC __thread */
  63         attribute_t       *attributes;        /**< list of attributes */
  64         type_t            *type;
  65 };
  66
  67 /**
  68  * An environment for parsing initializers (and compound literals).
  69  */
  70 typedef struct parse_initializer_env_t {
  71         type_t     *type;   /**< the type of the initializer. In case of an
  72                                  array type with unspecified size this gets
  73                                  adjusted to the actual size. */
  74         entity_t   *entity; /**< the variable that is initialized if any */
  75         bool        must_be_constant;
  76 } parse_initializer_env_t;
  77
  78 typedef entity_t* (*parsed_declaration_func) (entity_t *declaration, bool is_definition);
  79
  80 /** The current token. */
  81 static token_t              token;
  82 /** The lookahead ring-buffer. */
  83 static token_t              lookahead_buffer[MAX_LOOKAHEAD];
  84 /** Position of the next token in the lookahead buffer. */
  85 static size_t               lookahead_bufpos;
  86 static stack_entry_t       *environment_stack = NULL;
  87 static stack_entry_t       *label_stack       = NULL;
  88 static scope_t             *file_scope        = NULL;
  89 static scope_t             *current_scope     = NULL;
  90 /** Point to the current function declaration if inside a function. */
  91 static function_t          *current_function  = NULL;
  92 static entity_t            *current_entity    = NULL;
  93 static switch_statement_t  *current_switch    = NULL;
  94 static statement_t         *current_loop      = NULL;
  95 static statement_t         *current_parent    = NULL;
  96 static ms_try_statement_t  *current_try       = NULL;
  97 static linkage_kind_t       current_linkage;
  98 static goto_statement_t    *goto_first        = NULL;
  99 static goto_statement_t   **goto_anchor       = NULL;
 100 static label_statement_t   *label_first       = NULL;
 101 static label_statement_t  **label_anchor      = NULL;
 102 /** current translation unit. */
 103 static translation_unit_t  *unit              = NULL;
 104 /** true if we are in an __extension__ context. */
 105 static bool                 in_gcc_extension  = false;
 106 static struct obstack       temp_obst;
 107 static entity_t            *anonymous_entity;
 108 static declaration_t      **incomplete_arrays;
 109 static elf_visibility_tag_t default_visibility = ELF_VISIBILITY_DEFAULT;
 110
 111
 112 #define PUSH_CURRENT_ENTITY(entity) \
 113         entity_t *const new_current_entity = (entity); \
 114         entity_t *const old_current_entity = current_entity; \
 115         ((void)(current_entity = new_current_entity))
 116 #define POP_CURRENT_ENTITY() (assert(current_entity == new_current_entity), (void)(current_entity = old_current_entity))
 117
 118 #define PUSH_PARENT(stmt) \
 119         statement_t *const new_parent = (stmt); \
 120         statement_t *const old_parent = current_parent; \
 121         ((void)(current_parent = new_parent))
 122 #define POP_PARENT() (assert(current_parent == new_parent), (void)(current_parent = old_parent))
 123
 124 #define PUSH_SCOPE(scope) \
 125         size_t   const top       = environment_top(); \
 126         scope_t *const new_scope = (scope); \
 127         scope_t *const old_scope = (new_scope ? scope_push(new_scope) : NULL)
 128 #define PUSH_SCOPE_STATEMENT(scope) PUSH_SCOPE(c_mode & (_C99 | _CXX) ? (scope) : NULL)
 129 #define POP_SCOPE() (new_scope ? assert(current_scope == new_scope), scope_pop(old_scope), environment_pop_to(top) : (void)0)
 130
 131 #define PUSH_EXTENSION() \
 132         (void)0; \
 133         bool const old_gcc_extension = in_gcc_extension; \
 134         while (next_if(T___extension__)) { \
 135                 in_gcc_extension = true; \
 136         } \
 137         do {} while (0)
 138 #define POP_EXTENSION() \
 139         ((void)(in_gcc_extension = old_gcc_extension))
 140
 141 /** special symbol used for anonymous entities. */
 142 static symbol_t *sym_anonymous = NULL;
 143
 144 /** The token anchor set */
 145 static unsigned short token_anchor_set[T_LAST_TOKEN];
 146
 147 /** The current source position. */
 148 #define HERE (&token.base.source_position)
 149
 150 /** true if we are in GCC mode. */
 151 #define GNU_MODE ((c_mode & _GNUC) || in_gcc_extension)
 152
 153 static statement_t *parse_compound_statement(bool inside_expression_statement);
 154 static statement_t *parse_statement(void);
 155
 156 static expression_t *parse_subexpression(precedence_t);
 157 static expression_t *parse_expression(void);
 158 static type_t       *parse_typename(void);
 159 static void          parse_externals(void);
 160 static void          parse_external(void);
 161
 162 static void parse_compound_type_entries(compound_t *compound_declaration);
 163
 164 static void check_call_argument(type_t          *expected_type,
 165                                                                 call_argument_t *argument, unsigned pos);
 166
 167 typedef enum declarator_flags_t {
 168         DECL_FLAGS_NONE             = 0,
 169         DECL_MAY_BE_ABSTRACT        = 1U << 0,
 170         DECL_CREATE_COMPOUND_MEMBER = 1U << 1,
 171         DECL_IS_PARAMETER           = 1U << 2
 172 } declarator_flags_t;
 173
 174 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
 175                                   declarator_flags_t flags);
 176
 177 static void semantic_comparison(binary_expression_t *expression);
 178
 179 #define STORAGE_CLASSES       \
 180         STORAGE_CLASSES_NO_EXTERN \
 181         case T_extern:
 182
 183 #define STORAGE_CLASSES_NO_EXTERN \
 184         case T_typedef:         \
 185         case T_static:          \
 186         case T_auto:            \
 187         case T_register:        \
 188         case T___thread:
 189
 190 #define TYPE_QUALIFIERS     \
 191         case T_const:           \
 192         case T_restrict:        \
 193         case T_volatile:        \
 194         case T_inline:          \
 195         case T__forceinline:    \
 196         case T___attribute__:
 197
 198 #define COMPLEX_SPECIFIERS  \
 199         case T__Complex:
 200 #define IMAGINARY_SPECIFIERS \
 201         case T__Imaginary:
 202
 203 #define TYPE_SPECIFIERS       \
 204         case T__Bool:             \
 205         case T___builtin_va_list: \
 206         case T___typeof__:        \
 207         case T__declspec:         \
 208         case T_bool:              \
 209         case T_char:              \
 210         case T_double:            \
 211         case T_enum:              \
 212         case T_float:             \
 213         case T_int:               \
 214         case T_long:              \
 215         case T_short:             \
 216         case T_signed:            \
 217         case T_struct:            \
 218         case T_union:             \
 219         case T_unsigned:          \
 220         case T_void:              \
 221         case T_wchar_t:           \
 222         case T__int8:             \
 223         case T__int16:            \
 224         case T__int32:            \
 225         case T__int64:            \
 226         case T__int128:           \
 227         COMPLEX_SPECIFIERS        \
 228         IMAGINARY_SPECIFIERS
 229
 230 #define DECLARATION_START   \
 231         STORAGE_CLASSES         \
 232         TYPE_QUALIFIERS         \
 233         TYPE_SPECIFIERS
 234
 235 #define DECLARATION_START_NO_EXTERN \
 236         STORAGE_CLASSES_NO_EXTERN       \
 237         TYPE_QUALIFIERS                 \
 238         TYPE_SPECIFIERS
 239
 240 #define EXPRESSION_START              \
 241         case '!':                         \
 242         case '&':                         \
 243         case '(':                         \
 244         case '*':                         \
 245         case '+':                         \
 246         case '-':                         \
 247         case '~':                         \
 248         case T_ANDAND:                    \
 249         case T_CHARACTER_CONSTANT:        \
 250         case T_FLOATINGPOINT:             \
 251         case T_INTEGER:                   \
 252         case T_MINUSMINUS:                \
 253         case T_PLUSPLUS:                  \
 254         case T_STRING_LITERAL:            \
 255         case T_WIDE_CHARACTER_CONSTANT:   \
 256         case T___FUNCDNAME__:             \
 257         case T___FUNCSIG__:               \
 258         case T___FUNCTION__:              \
 259         case T___PRETTY_FUNCTION__:       \
 260         case T___alignof__:               \
 261         case T___builtin_classify_type:   \
 262         case T___builtin_constant_p:      \
 263         case T___builtin_isgreater:       \
 264         case T___builtin_isgreaterequal:  \
 265         case T___builtin_isless:          \
 266         case T___builtin_islessequal:     \
 267         case T___builtin_islessgreater:   \
 268         case T___builtin_isunordered:     \
 269         case T___builtin_offsetof:        \
 270         case T___builtin_va_arg:          \
 271         case T___builtin_va_copy:         \
 272         case T___builtin_va_start:        \
 273         case T___func__:                  \
 274         case T___noop:                    \
 275         case T__assume:                   \
 276         case T_delete:                    \
 277         case T_false:                     \
 278         case T_sizeof:                    \
 279         case T_throw:                     \
 280         case T_true:
 281
 282 /**
 283  * Returns the size of a statement node.
 284  *
 285  * @param kind  the statement kind
 286  */
 287 static size_t get_statement_struct_size(statement_kind_t kind)
 288 {
 289         static const size_t sizes[] = {
 290                 [STATEMENT_ERROR]         = sizeof(statement_base_t),
 291                 [STATEMENT_EMPTY]         = sizeof(statement_base_t),
 292                 [STATEMENT_COMPOUND]      = sizeof(compound_statement_t),
 293                 [STATEMENT_RETURN]        = sizeof(return_statement_t),
 294                 [STATEMENT_DECLARATION]   = sizeof(declaration_statement_t),
 295                 [STATEMENT_IF]            = sizeof(if_statement_t),
 296                 [STATEMENT_SWITCH]        = sizeof(switch_statement_t),
 297                 [STATEMENT_EXPRESSION]    = sizeof(expression_statement_t),
 298                 [STATEMENT_CONTINUE]      = sizeof(statement_base_t),
 299                 [STATEMENT_BREAK]         = sizeof(statement_base_t),
 300                 [STATEMENT_COMPUTED_GOTO] = sizeof(computed_goto_statement_t),
 301                 [STATEMENT_GOTO]          = sizeof(goto_statement_t),
 302                 [STATEMENT_LABEL]         = sizeof(label_statement_t),
 303                 [STATEMENT_CASE_LABEL]    = sizeof(case_label_statement_t),
 304                 [STATEMENT_WHILE]         = sizeof(while_statement_t),
 305                 [STATEMENT_DO_WHILE]      = sizeof(do_while_statement_t),
 306                 [STATEMENT_FOR]           = sizeof(for_statement_t),
 307                 [STATEMENT_ASM]           = sizeof(asm_statement_t),
 308                 [STATEMENT_MS_TRY]        = sizeof(ms_try_statement_t),
 309                 [STATEMENT_LEAVE]         = sizeof(leave_statement_t)
 310         };
 311         assert((size_t)kind < lengthof(sizes));
 312         assert(sizes[kind] != 0);
 313         return sizes[kind];
 314 }
 315
 316 /**
 317  * Returns the size of an expression node.
 318  *
 319  * @param kind  the expression kind
 320  */
 321 static size_t get_expression_struct_size(expression_kind_t kind)
 322 {
 323         static const size_t sizes[] = {
 324                 [EXPR_ERROR]                      = sizeof(expression_base_t),
 325                 [EXPR_REFERENCE]                  = sizeof(reference_expression_t),
 326                 [EXPR_ENUM_CONSTANT]              = sizeof(reference_expression_t),
 327                 [EXPR_LITERAL_BOOLEAN]            = sizeof(literal_expression_t),
 328                 [EXPR_LITERAL_INTEGER]            = sizeof(literal_expression_t),
 329                 [EXPR_LITERAL_FLOATINGPOINT]      = sizeof(literal_expression_t),
 330                 [EXPR_LITERAL_CHARACTER]          = sizeof(literal_expression_t),
 331                 [EXPR_LITERAL_WIDE_CHARACTER]     = sizeof(literal_expression_t),
 332                 [EXPR_STRING_LITERAL]             = sizeof(string_literal_expression_t),
 333                 [EXPR_WIDE_STRING_LITERAL]        = sizeof(string_literal_expression_t),
 334                 [EXPR_COMPOUND_LITERAL]           = sizeof(compound_literal_expression_t),
 335                 [EXPR_CALL]                       = sizeof(call_expression_t),
 336                 [EXPR_UNARY_FIRST]                = sizeof(unary_expression_t),
 337                 [EXPR_BINARY_FIRST]               = sizeof(binary_expression_t),
 338                 [EXPR_CONDITIONAL]                = sizeof(conditional_expression_t),
 339                 [EXPR_SELECT]                     = sizeof(select_expression_t),
 340                 [EXPR_ARRAY_ACCESS]               = sizeof(array_access_expression_t),
 341                 [EXPR_SIZEOF]                     = sizeof(typeprop_expression_t),
 342                 [EXPR_ALIGNOF]                    = sizeof(typeprop_expression_t),
 343                 [EXPR_CLASSIFY_TYPE]              = sizeof(classify_type_expression_t),
 344                 [EXPR_FUNCNAME]                   = sizeof(funcname_expression_t),
 345                 [EXPR_BUILTIN_CONSTANT_P]         = sizeof(builtin_constant_expression_t),
 346                 [EXPR_BUILTIN_TYPES_COMPATIBLE_P] = sizeof(builtin_types_compatible_expression_t),
 347                 [EXPR_OFFSETOF]                   = sizeof(offsetof_expression_t),
 348                 [EXPR_VA_START]                   = sizeof(va_start_expression_t),
 349                 [EXPR_VA_ARG]                     = sizeof(va_arg_expression_t),
 350                 [EXPR_VA_COPY]                    = sizeof(va_copy_expression_t),
 351                 [EXPR_STATEMENT]                  = sizeof(statement_expression_t),
 352                 [EXPR_LABEL_ADDRESS]              = sizeof(label_address_expression_t),
 353         };
 354         if (kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
 355                 return sizes[EXPR_UNARY_FIRST];
 356         }
 357         if (kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
 358                 return sizes[EXPR_BINARY_FIRST];
 359         }
 360         assert((size_t)kind < lengthof(sizes));
 361         assert(sizes[kind] != 0);
 362         return sizes[kind];
 363 }
 364
 365 /**
 366  * Allocate a statement node of given kind and initialize all
 367  * fields with zero. Sets its source position to the position
 368  * of the current token.
 369  */
 370 static statement_t *allocate_statement_zero(statement_kind_t kind)
 371 {
 372         size_t       size = get_statement_struct_size(kind);
 373         statement_t *res  = allocate_ast_zero(size);
 374
 375         res->base.kind            = kind;
 376         res->base.parent          = current_parent;
 377         res->base.source_position = *HERE;
 378         return res;
 379 }
 380
 381 /**
 382  * Allocate an expression node of given kind and initialize all
 383  * fields with zero.
 384  *
 385  * @param kind  the kind of the expression to allocate
 386  */
 387 static expression_t *allocate_expression_zero(expression_kind_t kind)
 388 {
 389         size_t        size = get_expression_struct_size(kind);
 390         expression_t *res  = allocate_ast_zero(size);
 391
 392         res->base.kind            = kind;
 393         res->base.type            = type_error_type;
 394         res->base.source_position = *HERE;
 395         return res;
 396 }
 397
 398 /**
 399  * Creates a new invalid expression at the source position
 400  * of the current token.
 401  */
 402 static expression_t *create_error_expression(void)
 403 {
 404         expression_t *expression = allocate_expression_zero(EXPR_ERROR);
 405         expression->base.type = type_error_type;
 406         return expression;
 407 }
 408
 409 /**
 410  * Creates a new invalid statement.
 411  */
 412 static statement_t *create_error_statement(void)
 413 {
 414         return allocate_statement_zero(STATEMENT_ERROR);
 415 }
 416
 417 /**
 418  * Allocate a new empty statement.
 419  */
 420 static statement_t *create_empty_statement(void)
 421 {
 422         return allocate_statement_zero(STATEMENT_EMPTY);
 423 }
 424
 425 /**
 426  * Returns the size of an initializer node.
 427  *
 428  * @param kind  the initializer kind
 429  */
 430 static size_t get_initializer_size(initializer_kind_t kind)
 431 {
 432         static const size_t sizes[] = {
 433                 [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
 434                 [INITIALIZER_STRING]      = sizeof(initializer_string_t),
 435                 [INITIALIZER_WIDE_STRING] = sizeof(initializer_wide_string_t),
 436                 [INITIALIZER_LIST]        = sizeof(initializer_list_t),
 437                 [INITIALIZER_DESIGNATOR]  = sizeof(initializer_designator_t)
 438         };
 439         assert((size_t)kind < lengthof(sizes));
 440         assert(sizes[kind] != 0);
 441         return sizes[kind];
 442 }
 443
 444 /**
 445  * Allocate an initializer node of given kind and initialize all
 446  * fields with zero.
 447  */
 448 static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 449 {
 450         initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
 451         result->kind          = kind;
 452
 453         return result;
 454 }
 455
 456 /**
 457  * Returns the index of the top element of the environment stack.
 458  */
 459 static size_t environment_top(void)
 460 {
 461         return ARR_LEN(environment_stack);
 462 }
 463
 464 /**
 465  * Returns the index of the top element of the global label stack.
 466  */
 467 static size_t label_top(void)
 468 {
 469         return ARR_LEN(label_stack);
 470 }
 471
 472 /**
 473  * Return the next token.
 474  */
 475 static inline void next_token(void)
 476 {
 477         token                              = lookahead_buffer[lookahead_bufpos];
 478         lookahead_buffer[lookahead_bufpos] = lexer_token;
 479         lexer_next_token();
 480
 481         lookahead_bufpos = (lookahead_bufpos + 1) % MAX_LOOKAHEAD;
 482
 483 #ifdef PRINT_TOKENS
 484         print_token(stderr, &token);
 485         fprintf(stderr, "\n");
 486 #endif
 487 }
 488
 489 #define eat(token_kind) (assert(token.kind == (token_kind)), next_token())
 490
 491 static inline bool next_if(token_kind_t const type)
 492 {
 493         if (token.kind == type) {
 494                 eat(type);
 495                 return true;
 496         } else {
 497                 return false;
 498         }
 499 }
 500
 501 /**
 502  * Return the next token with a given lookahead.
 503  */
 504 static inline const token_t *look_ahead(size_t num)
 505 {
 506         assert(0 < num && num <= MAX_LOOKAHEAD);
 507         size_t pos = (lookahead_bufpos + num - 1) % MAX_LOOKAHEAD;
 508         return &lookahead_buffer[pos];
 509 }
 510
 511 /**
 512  * Adds a token type to the token type anchor set (a multi-set).
 513  */
 514 static void add_anchor_token(token_kind_t const token_kind)
 515 {
 516         assert(token_kind < T_LAST_TOKEN);
 517         ++token_anchor_set[token_kind];
 518 }
 519
 520 /**
 521  * Remove a token type from the token type anchor set (a multi-set).
 522  */
 523 static void rem_anchor_token(token_kind_t const token_kind)
 524 {
 525         assert(token_kind < T_LAST_TOKEN);
 526         assert(token_anchor_set[token_kind] != 0);
 527         --token_anchor_set[token_kind];
 528 }
 529
 530 /**
 531  * Eat tokens until a matching token type is found.
 532  */
 533 static void eat_until_matching_token(token_kind_t const type)
 534 {
 535         token_kind_t end_token;
 536         switch (type) {
 537                 case '(': end_token = ')';  break;
 538                 case '{': end_token = '}';  break;
 539                 case '[': end_token = ']';  break;
 540                 default:  end_token = type; break;
 541         }
 542
 543         unsigned parenthesis_count = 0;
 544         unsigned brace_count       = 0;
 545         unsigned bracket_count     = 0;
 546         while (token.kind        != end_token ||
 547                parenthesis_count != 0         ||
 548                brace_count       != 0         ||
 549                bracket_count     != 0) {
 550                 switch (token.kind) {
 551                 case T_EOF: return;
 552                 case '(': ++parenthesis_count; break;
 553                 case '{': ++brace_count;       break;
 554                 case '[': ++bracket_count;     break;
 555
 556                 case ')':
 557                         if (parenthesis_count > 0)
 558                                 --parenthesis_count;
 559                         goto check_stop;
 560
 561                 case '}':
 562                         if (brace_count > 0)
 563                                 --brace_count;
 564                         goto check_stop;
 565
 566                 case ']':
 567                         if (bracket_count > 0)
 568                                 --bracket_count;
 569 check_stop:
 570                         if (token.kind        == end_token &&
 571                             parenthesis_count == 0         &&
 572                             brace_count       == 0         &&
 573                             bracket_count     == 0)
 574                                 return;
 575                         break;
 576
 577                 default:
 578                         break;
 579                 }
 580                 next_token();
 581         }
 582 }
 583
 584 /**
 585  * Eat input tokens until an anchor is found.
 586  */
 587 static void eat_until_anchor(void)
 588 {
 589         while (token_anchor_set[token.kind] == 0) {
 590                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
 591                         eat_until_matching_token(token.kind);
 592                 next_token();
 593         }
 594 }
 595
 596 /**
 597  * Eat a whole block from input tokens.
 598  */
 599 static void eat_block(void)
 600 {
 601         eat_until_matching_token('{');
 602         next_if('}');
 603 }
 604
 605 /**
 606  * Report a parse error because an expected token was not found.
 607  */
 608 static
 609 #if defined __GNUC__ && __GNUC__ >= 4
 610 __attribute__((sentinel))
 611 #endif
 612 void parse_error_expected(const char *message, ...)
 613 {
 614         if (message != NULL) {
 615                 errorf(HERE, "%s", message);
 616         }
 617         va_list ap;
 618         va_start(ap, message);
 619         errorf(HERE, "got %K, expected %#k", &token, &ap, ", ");
 620         va_end(ap);
 621 }
 622
 623 /**
 624  * Report an incompatible type.
 625  */
 626 static void type_error_incompatible(const char *msg,
 627                 const source_position_t *source_position, type_t *type1, type_t *type2)
 628 {
 629         errorf(source_position, "%s, incompatible types: '%T' - '%T'",
 630                msg, type1, type2);
 631 }
 632
 633 /**
 634  * Expect the current token is the expected token.
 635  * If not, generate an error and skip until the next anchor.
 636  */
 637 static void expect(token_kind_t const expected)
 638 {
 639         if (UNLIKELY(token.kind != expected)) {
 640                 parse_error_expected(NULL, expected, NULL);
 641                 add_anchor_token(expected);
 642                 eat_until_anchor();
 643                 rem_anchor_token(expected);
 644                 if (token.kind != expected)
 645                         return;
 646         }
 647         eat(expected);
 648 }
 649
 650 static symbol_t *expect_identifier(char const *const context, source_position_t *const pos)
 651 {
 652         if (token.kind != T_IDENTIFIER) {
 653                 parse_error_expected(context, T_IDENTIFIER, NULL);
 654                 add_anchor_token(T_IDENTIFIER);
 655                 eat_until_anchor();
 656                 rem_anchor_token(T_IDENTIFIER);
 657                 if (token.kind != T_IDENTIFIER)
 658                         return NULL;
 659         }
 660         symbol_t *const sym = token.base.symbol;
 661         if (pos)
 662                 *pos = *HERE;
 663         eat(T_IDENTIFIER);
 664         return sym;
 665 }
 666
 667 /**
 668  * Push a given scope on the scope stack and make it the
 669  * current scope
 670  */
 671 static scope_t *scope_push(scope_t *new_scope)
 672 {
 673         if (current_scope != NULL) {
 674                 new_scope->depth = current_scope->depth + 1;
 675         }
 676
 677         scope_t *old_scope = current_scope;
 678         current_scope      = new_scope;
 679         return old_scope;
 680 }
 681
 682 /**
 683  * Pop the current scope from the scope stack.
 684  */
 685 static void scope_pop(scope_t *old_scope)
 686 {
 687         current_scope = old_scope;
 688 }
 689
 690 /**
 691  * Search an entity by its symbol in a given namespace.
 692  */
 693 static entity_t *get_entity(const symbol_t *const symbol,
 694                             namespace_tag_t namespc)
 695 {
 696         entity_t *entity = symbol->entity;
 697         for (; entity != NULL; entity = entity->base.symbol_next) {
 698                 if ((namespace_tag_t)entity->base.namespc == namespc)
 699                         return entity;
 700         }
 701
 702         return NULL;
 703 }
 704
 705 /* §6.2.3:1 24)  There is only one name space for tags even though three are
 706  * possible. */
 707 static entity_t *get_tag(symbol_t const *const symbol,
 708                          entity_kind_tag_t const kind)
 709 {
 710         entity_t *entity = get_entity(symbol, NAMESPACE_TAG);
 711         if (entity != NULL && (entity_kind_tag_t)entity->kind != kind) {
 712                 errorf(HERE,
 713                                 "'%Y' defined as wrong kind of tag (previous definition %P)",
 714                                 symbol, &entity->base.source_position);
 715                 entity = NULL;
 716         }
 717         return entity;
 718 }
 719
 720 /**
 721  * pushs an entity on the environment stack and links the corresponding symbol
 722  * it.
 723  */
 724 static void stack_push(stack_entry_t **stack_ptr, entity_t *entity)
 725 {
 726         symbol_t           *symbol  = entity->base.symbol;
 727         entity_namespace_t  namespc = entity->base.namespc;
 728         assert(namespc != 0);
 729
 730         /* replace/add entity into entity list of the symbol */
 731         entity_t **anchor;
 732         entity_t  *iter;
 733         for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 734                 iter = *anchor;
 735                 if (iter == NULL)
 736                         break;
 737
 738                 /* replace an entry? */
 739                 if (iter->base.namespc == namespc) {
 740                         entity->base.symbol_next = iter->base.symbol_next;
 741                         break;
 742                 }
 743         }
 744         *anchor = entity;
 745
 746         /* remember old declaration */
 747         stack_entry_t entry;
 748         entry.symbol     = symbol;
 749         entry.old_entity = iter;
 750         entry.namespc    = namespc;
 751         ARR_APP1(stack_entry_t, *stack_ptr, entry);
 752 }
 753
 754 /**
 755  * Push an entity on the environment stack.
 756  */
 757 static void environment_push(entity_t *entity)
 758 {
 759         assert(entity->base.source_position.input_name != NULL);
 760         assert(entity->base.parent_scope != NULL);
 761         stack_push(&environment_stack, entity);
 762 }
 763
 764 /**
 765  * Push a declaration on the global label stack.
 766  *
 767  * @param declaration  the declaration
 768  */
 769 static void label_push(entity_t *label)
 770 {
 771         /* we abuse the parameters scope as parent for the labels */
 772         label->base.parent_scope = &current_function->parameters;
 773         stack_push(&label_stack, label);
 774 }
 775
 776 /**
 777  * pops symbols from the environment stack until @p new_top is the top element
 778  */
 779 static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 780 {
 781         stack_entry_t *stack = *stack_ptr;
 782         size_t         top   = ARR_LEN(stack);
 783         size_t         i;
 784
 785         assert(new_top <= top);
 786         if (new_top == top)
 787                 return;
 788
 789         for (i = top; i > new_top; --i) {
 790                 stack_entry_t *entry = &stack[i - 1];
 791
 792                 entity_t           *old_entity = entry->old_entity;
 793                 symbol_t           *symbol     = entry->symbol;
 794                 entity_namespace_t  namespc    = entry->namespc;
 795
 796                 /* replace with old_entity/remove */
 797                 entity_t **anchor;
 798                 entity_t  *iter;
 799                 for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 800                         iter = *anchor;
 801                         assert(iter != NULL);
 802                         /* replace an entry? */
 803                         if (iter->base.namespc == namespc)
 804                                 break;
 805                 }
 806
 807                 /* restore definition from outer scopes (if there was one) */
 808                 if (old_entity != NULL) {
 809                         old_entity->base.symbol_next = iter->base.symbol_next;
 810                         *anchor                      = old_entity;
 811                 } else {
 812                         /* remove entry from list */
 813                         *anchor = iter->base.symbol_next;
 814                 }
 815         }
 816
 817         ARR_SHRINKLEN(*stack_ptr, new_top);
 818 }
 819
 820 /**
 821  * Pop all entries from the environment stack until the new_top
 822  * is reached.
 823  *
 824  * @param new_top  the new stack top
 825  */
 826 static void environment_pop_to(size_t new_top)
 827 {
 828         stack_pop_to(&environment_stack, new_top);
 829 }
 830
 831 /**
 832  * Pop all entries from the global label stack until the new_top
 833  * is reached.
 834  *
 835  * @param new_top  the new stack top
 836  */
 837 static void label_pop_to(size_t new_top)
 838 {
 839         stack_pop_to(&label_stack, new_top);
 840 }
 841
 842 static atomic_type_kind_t get_akind(const type_t *type)
 843 {
 844         assert(type->kind == TYPE_ATOMIC || type->kind == TYPE_COMPLEX
 845                || type->kind == TYPE_IMAGINARY || type->kind == TYPE_ENUM);
 846         return type->atomic.akind;
 847 }
 848
 849 /**
 850  * §6.3.1.1:2  Do integer promotion for a given type.
 851  *
 852  * @param type  the type to promote
 853  * @return the promoted type
 854  */
 855 static type_t *promote_integer(type_t *type)
 856 {
 857         if (get_akind_rank(get_akind(type)) < get_akind_rank(ATOMIC_TYPE_INT))
 858                 type = type_int;
 859
 860         return type;
 861 }
 862
 863 /**
 864  * Check if a given expression represents a null pointer constant.
 865  *
 866  * @param expression  the expression to check
 867  */
 868 static bool is_null_pointer_constant(const expression_t *expression)
 869 {
 870         /* skip void* cast */
 871         if (expression->kind == EXPR_UNARY_CAST) {
 872                 type_t *const type = skip_typeref(expression->base.type);
 873                 if (types_compatible(type, type_void_ptr))
 874                         expression = expression->unary.value;
 875         }
 876
 877         type_t *const type = skip_typeref(expression->base.type);
 878         if (!is_type_integer(type))
 879                 return false;
 880         switch (is_constant_expression(expression)) {
 881                 case EXPR_CLASS_ERROR:    return true;
 882                 case EXPR_CLASS_CONSTANT: return !fold_constant_to_bool(expression);
 883                 default:                  return false;
 884         }
 885 }
 886
 887 /**
 888  * Create an implicit cast expression.
 889  *
 890  * @param expression  the expression to cast
 891  * @param dest_type   the destination type
 892  */
 893 static expression_t *create_implicit_cast(expression_t *expression,
 894                                           type_t *dest_type)
 895 {
 896         type_t *const source_type = expression->base.type;
 897
 898         if (source_type == dest_type)
 899                 return expression;
 900
 901         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
 902         cast->unary.value   = expression;
 903         cast->base.type     = dest_type;
 904         cast->base.implicit = true;
 905
 906         return cast;
 907 }
 908
 909 typedef enum assign_error_t {
 910         ASSIGN_SUCCESS,
 911         ASSIGN_ERROR_INCOMPATIBLE,
 912         ASSIGN_ERROR_POINTER_QUALIFIER_MISSING,
 913         ASSIGN_WARNING_POINTER_INCOMPATIBLE,
 914         ASSIGN_WARNING_POINTER_FROM_INT,
 915         ASSIGN_WARNING_INT_FROM_POINTER
 916 } assign_error_t;
 917
 918 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)
 919 {
 920         type_t *const orig_type_right = right->base.type;
 921         type_t *const type_left       = skip_typeref(orig_type_left);
 922         type_t *const type_right      = skip_typeref(orig_type_right);
 923
 924         switch (error) {
 925         case ASSIGN_SUCCESS:
 926                 return;
 927         case ASSIGN_ERROR_INCOMPATIBLE:
 928                 errorf(pos, "destination type '%T' in %s is incompatible with type '%T'", orig_type_left, context, orig_type_right);
 929                 return;
 930
 931         case ASSIGN_ERROR_POINTER_QUALIFIER_MISSING: {
 932                 type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
 933                 type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 934
 935                 /* the left type has all qualifiers from the right type */
 936                 unsigned missing_qualifiers = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 937                 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);
 938                 return;
 939         }
 940
 941         case ASSIGN_WARNING_POINTER_INCOMPATIBLE:
 942                 warningf(WARN_OTHER, pos, "destination type '%T' in %s is incompatible with '%E' of type '%T'", orig_type_left, context, right, orig_type_right);
 943                 return;
 944
 945         case ASSIGN_WARNING_POINTER_FROM_INT:
 946                 warningf(WARN_OTHER, pos, "%s makes pointer '%T' from integer '%T' without a cast", context, orig_type_left, orig_type_right);
 947                 return;
 948
 949         case ASSIGN_WARNING_INT_FROM_POINTER:
 950                 warningf(WARN_OTHER, pos, "%s makes integer '%T' from pointer '%T' without a cast", context, orig_type_left, orig_type_right);
 951                 return;
 952
 953         default:
 954                 panic("invalid error value");
 955         }
 956 }
 957
 958 /** Implements the rules from §6.5.16.1 */
 959 static assign_error_t semantic_assign(type_t *orig_type_left,
 960                                       const expression_t *const right)
 961 {
 962         type_t *const orig_type_right = right->base.type;
 963         type_t *const type_left       = skip_typeref(orig_type_left);
 964         type_t *const type_right      = skip_typeref(orig_type_right);
 965
 966         if (is_type_pointer(type_left)) {
 967                 if (is_null_pointer_constant(right)) {
 968                         return ASSIGN_SUCCESS;
 969                 } else if (is_type_pointer(type_right)) {
 970                         type_t *points_to_left
 971                                 = skip_typeref(type_left->pointer.points_to);
 972                         type_t *points_to_right
 973                                 = skip_typeref(type_right->pointer.points_to);
 974                         assign_error_t res = ASSIGN_SUCCESS;
 975
 976                         /* the left type has all qualifiers from the right type */
 977                         unsigned missing_qualifiers
 978                                 = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 979                         if (missing_qualifiers != 0) {
 980                                 res = ASSIGN_ERROR_POINTER_QUALIFIER_MISSING;
 981                         }
 982
 983                         points_to_left  = get_unqualified_type(points_to_left);
 984                         points_to_right = get_unqualified_type(points_to_right);
 985
 986                         if (is_type_void(points_to_left))
 987                                 return res;
 988
 989                         if (is_type_void(points_to_right)) {
 990                                 /* ISO/IEC 14882:1998(E) §C.1.2:6 */
 991                                 return c_mode & _CXX ? ASSIGN_ERROR_INCOMPATIBLE : res;
 992                         }
 993
 994                         if (!types_compatible(points_to_left, points_to_right)) {
 995                                 return ASSIGN_WARNING_POINTER_INCOMPATIBLE;
 996                         }
 997
 998                         return res;
 999                 } else if (is_type_integer(type_right)) {
1000                         return ASSIGN_WARNING_POINTER_FROM_INT;
1001                 }
1002         } else if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
1003                         (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
1004                                 && is_type_pointer(type_right))) {
1005                 return ASSIGN_SUCCESS;
1006         } else if (is_type_compound(type_left) && is_type_compound(type_right)) {
1007                 type_t *const unqual_type_left  = get_unqualified_type(type_left);
1008                 type_t *const unqual_type_right = get_unqualified_type(type_right);
1009                 if (types_compatible(unqual_type_left, unqual_type_right)) {
1010                         return ASSIGN_SUCCESS;
1011                 }
1012         } else if (is_type_integer(type_left) && is_type_pointer(type_right)) {
1013                 return ASSIGN_WARNING_INT_FROM_POINTER;
1014         }
1015
1016         if (!is_type_valid(type_left) || !is_type_valid(type_right))
1017                 return ASSIGN_SUCCESS;
1018
1019         return ASSIGN_ERROR_INCOMPATIBLE;
1020 }
1021
1022 static expression_t *parse_constant_expression(void)
1023 {
1024         expression_t *result = parse_subexpression(PREC_CONDITIONAL);
1025
1026         if (is_constant_expression(result) == EXPR_CLASS_VARIABLE) {
1027                 errorf(&result->base.source_position,
1028                        "expression '%E' is not constant", result);
1029         }
1030
1031         return result;
1032 }
1033
1034 static expression_t *parse_assignment_expression(void)
1035 {
1036         return parse_subexpression(PREC_ASSIGNMENT);
1037 }
1038
1039 static void append_string(string_t const *const s)
1040 {
1041         /* FIXME Using the ast_obstack is a hack.  Using the symbol_obstack is not
1042          * possible, because other tokens are grown there alongside. */
1043         obstack_grow(&ast_obstack, s->begin, s->size - 1);
1044 }
1045
1046 static string_t finish_string(void)
1047 {
1048         obstack_1grow(&ast_obstack, '\0');
1049         size_t      const size   = obstack_object_size(&ast_obstack);
1050         char const *const string = obstack_finish(&ast_obstack);
1051         return (string_t){ string, size };
1052 }
1053
1054 static string_t concat_string_literals(string_encoding_t *const out_enc)
1055 {
1056         assert(token.kind == T_STRING_LITERAL);
1057
1058         string_t          result;
1059         string_encoding_t enc = token.string.encoding;
1060         if (look_ahead(1)->kind == T_STRING_LITERAL) {
1061                 append_string(&token.string.string);
1062                 eat(T_STRING_LITERAL);
1063                 warningf(WARN_TRADITIONAL, HERE, "traditional C rejects string constant concatenation");
1064                 do {
1065                         if (token.string.encoding != STRING_ENCODING_CHAR) {
1066                                 enc = token.string.encoding;
1067                         }
1068                         append_string(&token.string.string);
1069                         eat(T_STRING_LITERAL);
1070                 } while (token.kind == T_STRING_LITERAL);
1071                 result = finish_string();
1072         } else {
1073                 result = token.string.string;
1074                 eat(T_STRING_LITERAL);
1075         }
1076
1077         *out_enc = enc;
1078         return result;
1079 }
1080
1081 static string_t parse_string_literals(void)
1082 {
1083         string_encoding_t       enc;
1084         source_position_t const pos = *HERE;
1085         string_t          const res = concat_string_literals(&enc);
1086
1087         if (enc != STRING_ENCODING_CHAR) {
1088                 errorf(&pos, "expected plain string literal, got wide string literal");
1089         }
1090
1091         return res;
1092 }
1093
1094 static attribute_t *allocate_attribute_zero(attribute_kind_t kind)
1095 {
1096         attribute_t *attribute = allocate_ast_zero(sizeof(*attribute));
1097         attribute->kind            = kind;
1098         attribute->source_position = *HERE;
1099         return attribute;
1100 }
1101
1102 /**
1103  * Parse (gcc) attribute argument. From gcc comments in gcc source:
1104  *
1105  *  attribute:
1106  *    __attribute__ ( ( attribute-list ) )
1107  *
1108  *  attribute-list:
1109  *    attrib
1110  *    attribute_list , attrib
1111  *
1112  *  attrib:
1113  *    empty
1114  *    any-word
1115  *    any-word ( identifier )
1116  *    any-word ( identifier , nonempty-expr-list )
1117  *    any-word ( expr-list )
1118  *
1119  *  where the "identifier" must not be declared as a type, and
1120  *  "any-word" may be any identifier (including one declared as a
1121  *  type), a reserved word storage class specifier, type specifier or
1122  *  type qualifier.  ??? This still leaves out most reserved keywords
1123  *  (following the old parser), shouldn't we include them, and why not
1124  *  allow identifiers declared as types to start the arguments?
1125  *
1126  *  Matze: this all looks confusing and little systematic, so we're even less
1127  *  strict and parse any list of things which are identifiers or
1128  *  (assignment-)expressions.
1129  */
1130 static attribute_argument_t *parse_attribute_arguments(void)
1131 {
1132         attribute_argument_t  *first  = NULL;
1133         attribute_argument_t **anchor = &first;
1134         if (token.kind != ')') do {
1135                 attribute_argument_t *argument = allocate_ast_zero(sizeof(*argument));
1136
1137                 /* is it an identifier */
1138                 if (token.kind == T_IDENTIFIER
1139                                 && (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
1140                         argument->kind     = ATTRIBUTE_ARGUMENT_SYMBOL;
1141                         argument->v.symbol = token.base.symbol;
1142                         eat(T_IDENTIFIER);
1143                 } else {
1144                         /* must be an expression */
1145                         expression_t *expression = parse_assignment_expression();
1146
1147                         argument->kind         = ATTRIBUTE_ARGUMENT_EXPRESSION;
1148                         argument->v.expression = expression;
1149                 }
1150
1151                 /* append argument */
1152                 *anchor = argument;
1153                 anchor  = &argument->next;
1154         } while (next_if(','));
1155         expect(')');
1156         return first;
1157 }
1158
1159 static attribute_t *parse_attribute_asm(void)
1160 {
1161         attribute_t *attribute = allocate_attribute_zero(ATTRIBUTE_GNU_ASM);
1162         eat(T_asm);
1163         expect('(');
1164         attribute->a.arguments = parse_attribute_arguments();
1165         return attribute;
1166 }
1167
1168 static attribute_t *parse_attribute_gnu_single(void)
1169 {
1170         /* parse "any-word" */
1171         symbol_t *const symbol = token.base.symbol;
1172         if (symbol == NULL) {
1173                 parse_error_expected("while parsing attribute((", T_IDENTIFIER, NULL);
1174                 return NULL;
1175         }
1176
1177         attribute_kind_t  kind;
1178         char const *const name = symbol->string;
1179         for (kind = ATTRIBUTE_GNU_FIRST;; ++kind) {
1180                 if (kind > ATTRIBUTE_GNU_LAST) {
1181                         warningf(WARN_ATTRIBUTE, HERE, "unknown attribute '%s' ignored", name);
1182                         /* TODO: we should still save the attribute in the list... */
1183                         kind = ATTRIBUTE_UNKNOWN;
1184                         break;
1185                 }
1186
1187                 const char *attribute_name = get_attribute_name(kind);
1188                 if (attribute_name != NULL && streq_underscore(attribute_name, name))
1189                         break;
1190         }
1191
1192         attribute_t *attribute = allocate_attribute_zero(kind);
1193         next_token();
1194
1195         /* parse arguments */
1196         if (next_if('('))
1197                 attribute->a.arguments = parse_attribute_arguments();
1198
1199         return attribute;
1200 }
1201
1202 static attribute_t *parse_attribute_gnu(void)
1203 {
1204         attribute_t  *first  = NULL;
1205         attribute_t **anchor = &first;
1206
1207         eat(T___attribute__);
1208         add_anchor_token(')');
1209         add_anchor_token(',');
1210         expect('(');
1211         expect('(');
1212
1213         if (token.kind != ')') do {
1214                 attribute_t *attribute = parse_attribute_gnu_single();
1215                 if (attribute) {
1216                         *anchor = attribute;
1217                         anchor  = &attribute->next;
1218                 }
1219         } while (next_if(','));
1220         rem_anchor_token(',');
1221         rem_anchor_token(')');
1222
1223         expect(')');
1224         expect(')');
1225         return first;
1226 }
1227
1228 /** Parse attributes. */
1229 static attribute_t *parse_attributes(attribute_t *first)
1230 {
1231         attribute_t **anchor = &first;
1232         for (;;) {
1233                 while (*anchor != NULL)
1234                         anchor = &(*anchor)->next;
1235
1236                 attribute_t *attribute;
1237                 switch (token.kind) {
1238                 case T___attribute__:
1239                         attribute = parse_attribute_gnu();
1240                         if (attribute == NULL)
1241                                 continue;
1242                         break;
1243
1244                 case T_asm:
1245                         attribute = parse_attribute_asm();
1246                         break;
1247
1248                 case T_cdecl:
1249                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_CDECL);
1250                         eat(T_cdecl);
1251                         break;
1252
1253                 case T__fastcall:
1254                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FASTCALL);
1255                         eat(T__fastcall);
1256                         break;
1257
1258                 case T__forceinline:
1259                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FORCEINLINE);
1260                         eat(T__forceinline);
1261                         break;
1262
1263                 case T__stdcall:
1264                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_STDCALL);
1265                         eat(T__stdcall);
1266                         break;
1267
1268                 case T___thiscall:
1269                         /* TODO record modifier */
1270                         warningf(WARN_OTHER, HERE, "Ignoring declaration modifier %K", &token);
1271                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_THISCALL);
1272                         eat(T___thiscall);
1273                         break;
1274
1275                 default:
1276                         return first;
1277                 }
1278
1279                 *anchor = attribute;
1280                 anchor  = &attribute->next;
1281         }
1282 }
1283
1284 static void mark_vars_read(expression_t *expr, entity_t *lhs_ent);
1285
1286 static entity_t *determine_lhs_ent(expression_t *const expr,
1287                                    entity_t *lhs_ent)
1288 {
1289         switch (expr->kind) {
1290                 case EXPR_REFERENCE: {
1291                         entity_t *const entity = expr->reference.entity;
1292                         /* we should only find variables as lvalues... */
1293                         if (entity->base.kind != ENTITY_VARIABLE
1294                                         && entity->base.kind != ENTITY_PARAMETER)
1295                                 return NULL;
1296
1297                         return entity;
1298                 }
1299
1300                 case EXPR_ARRAY_ACCESS: {
1301                         expression_t *const ref = expr->array_access.array_ref;
1302                         entity_t     *      ent = NULL;
1303                         if (is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1304                                 ent     = determine_lhs_ent(ref, lhs_ent);
1305                                 lhs_ent = ent;
1306                         } else {
1307                                 mark_vars_read(ref, lhs_ent);
1308                         }
1309                         mark_vars_read(expr->array_access.index, lhs_ent);
1310                         return ent;
1311                 }
1312
1313                 case EXPR_SELECT: {
1314                         mark_vars_read(expr->select.compound, lhs_ent);
1315                         if (is_type_compound(skip_typeref(expr->base.type)))
1316                                 return determine_lhs_ent(expr->select.compound, lhs_ent);
1317                         return NULL;
1318                 }
1319
1320                 case EXPR_UNARY_DEREFERENCE: {
1321                         expression_t *const val = expr->unary.value;
1322                         if (val->kind == EXPR_UNARY_TAKE_ADDRESS) {
1323                                 /* *&x is a NOP */
1324                                 return determine_lhs_ent(val->unary.value, lhs_ent);
1325                         } else {
1326                                 mark_vars_read(val, NULL);
1327                                 return NULL;
1328                         }
1329                 }
1330
1331                 default:
1332                         mark_vars_read(expr, NULL);
1333                         return NULL;
1334         }
1335 }
1336
1337 #define ENT_ANY ((entity_t*)-1)
1338
1339 /**
1340  * Mark declarations, which are read.  This is used to detect variables, which
1341  * are never read.
1342  * Example:
1343  * x = x + 1;
1344  *   x is not marked as "read", because it is only read to calculate its own new
1345  *   value.
1346  *
1347  * x += y; y += x;
1348  *   x and y are not detected as "not read", because multiple variables are
1349  *   involved.
1350  */
1351 static void mark_vars_read(expression_t *const expr, entity_t *lhs_ent)
1352 {
1353         switch (expr->kind) {
1354                 case EXPR_REFERENCE: {
1355                         entity_t *const entity = expr->reference.entity;
1356                         if (entity->kind != ENTITY_VARIABLE
1357                                         && entity->kind != ENTITY_PARAMETER)
1358                                 return;
1359
1360                         if (lhs_ent != entity && lhs_ent != ENT_ANY) {
1361                                 entity->variable.read = true;
1362                         }
1363                         return;
1364                 }
1365
1366                 case EXPR_CALL:
1367                         // TODO respect pure/const
1368                         mark_vars_read(expr->call.function, NULL);
1369                         for (call_argument_t *arg = expr->call.arguments; arg != NULL; arg = arg->next) {
1370                                 mark_vars_read(arg->expression, NULL);
1371                         }
1372                         return;
1373
1374                 case EXPR_CONDITIONAL:
1375                         // TODO lhs_decl should depend on whether true/false have an effect
1376                         mark_vars_read(expr->conditional.condition, NULL);
1377                         if (expr->conditional.true_expression != NULL)
1378                                 mark_vars_read(expr->conditional.true_expression, lhs_ent);
1379                         mark_vars_read(expr->conditional.false_expression, lhs_ent);
1380                         return;
1381
1382                 case EXPR_SELECT:
1383                         if (lhs_ent == ENT_ANY
1384                                         && !is_type_compound(skip_typeref(expr->base.type)))
1385                                 lhs_ent = NULL;
1386                         mark_vars_read(expr->select.compound, lhs_ent);
1387                         return;
1388
1389                 case EXPR_ARRAY_ACCESS: {
1390                         mark_vars_read(expr->array_access.index, lhs_ent);
1391                         expression_t *const ref = expr->array_access.array_ref;
1392                         if (!is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1393                                 if (lhs_ent == ENT_ANY)
1394                                         lhs_ent = NULL;
1395                         }
1396                         mark_vars_read(ref, lhs_ent);
1397                         return;
1398                 }
1399
1400                 case EXPR_VA_ARG:
1401                         mark_vars_read(expr->va_arge.ap, lhs_ent);
1402                         return;
1403
1404                 case EXPR_VA_COPY:
1405                         mark_vars_read(expr->va_copye.src, lhs_ent);
1406                         return;
1407
1408                 case EXPR_UNARY_CAST:
1409                         /* Special case: Use void cast to mark a variable as "read" */
1410                         if (is_type_void(skip_typeref(expr->base.type)))
1411                                 lhs_ent = NULL;
1412                         goto unary;
1413
1414
1415                 case EXPR_UNARY_THROW:
1416                         if (expr->unary.value == NULL)
1417                                 return;
1418                         /* FALLTHROUGH */
1419                 case EXPR_UNARY_DEREFERENCE:
1420                 case EXPR_UNARY_DELETE:
1421                 case EXPR_UNARY_DELETE_ARRAY:
1422                         if (lhs_ent == ENT_ANY)
1423                                 lhs_ent = NULL;
1424                         goto unary;
1425
1426                 case EXPR_UNARY_NEGATE:
1427                 case EXPR_UNARY_PLUS:
1428                 case EXPR_UNARY_BITWISE_NEGATE:
1429                 case EXPR_UNARY_NOT:
1430                 case EXPR_UNARY_TAKE_ADDRESS:
1431                 case EXPR_UNARY_POSTFIX_INCREMENT:
1432                 case EXPR_UNARY_POSTFIX_DECREMENT:
1433                 case EXPR_UNARY_PREFIX_INCREMENT:
1434                 case EXPR_UNARY_PREFIX_DECREMENT:
1435                 case EXPR_UNARY_ASSUME:
1436 unary:
1437                         mark_vars_read(expr->unary.value, lhs_ent);
1438                         return;
1439
1440                 case EXPR_BINARY_ADD:
1441                 case EXPR_BINARY_SUB:
1442                 case EXPR_BINARY_MUL:
1443                 case EXPR_BINARY_DIV:
1444                 case EXPR_BINARY_MOD:
1445                 case EXPR_BINARY_EQUAL:
1446                 case EXPR_BINARY_NOTEQUAL:
1447                 case EXPR_BINARY_LESS:
1448                 case EXPR_BINARY_LESSEQUAL:
1449                 case EXPR_BINARY_GREATER:
1450                 case EXPR_BINARY_GREATEREQUAL:
1451                 case EXPR_BINARY_BITWISE_AND:
1452                 case EXPR_BINARY_BITWISE_OR:
1453                 case EXPR_BINARY_BITWISE_XOR:
1454                 case EXPR_BINARY_LOGICAL_AND:
1455                 case EXPR_BINARY_LOGICAL_OR:
1456                 case EXPR_BINARY_SHIFTLEFT:
1457                 case EXPR_BINARY_SHIFTRIGHT:
1458                 case EXPR_BINARY_COMMA:
1459                 case EXPR_BINARY_ISGREATER:
1460                 case EXPR_BINARY_ISGREATEREQUAL:
1461                 case EXPR_BINARY_ISLESS:
1462                 case EXPR_BINARY_ISLESSEQUAL:
1463                 case EXPR_BINARY_ISLESSGREATER:
1464                 case EXPR_BINARY_ISUNORDERED:
1465                         mark_vars_read(expr->binary.left,  lhs_ent);
1466                         mark_vars_read(expr->binary.right, lhs_ent);
1467                         return;
1468
1469                 case EXPR_BINARY_ASSIGN:
1470                 case EXPR_BINARY_MUL_ASSIGN:
1471                 case EXPR_BINARY_DIV_ASSIGN:
1472                 case EXPR_BINARY_MOD_ASSIGN:
1473                 case EXPR_BINARY_ADD_ASSIGN:
1474                 case EXPR_BINARY_SUB_ASSIGN:
1475                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:
1476                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:
1477                 case EXPR_BINARY_BITWISE_AND_ASSIGN:
1478                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:
1479                 case EXPR_BINARY_BITWISE_OR_ASSIGN: {
1480                         if (lhs_ent == ENT_ANY)
1481                                 lhs_ent = NULL;
1482                         lhs_ent = determine_lhs_ent(expr->binary.left, lhs_ent);
1483                         mark_vars_read(expr->binary.right, lhs_ent);
1484                         return;
1485                 }
1486
1487                 case EXPR_VA_START:
1488                         determine_lhs_ent(expr->va_starte.ap, lhs_ent);
1489                         return;
1490
1491                 case EXPR_LITERAL_CASES:
1492                 case EXPR_ERROR:
1493                 case EXPR_STRING_LITERAL:
1494                 case EXPR_WIDE_STRING_LITERAL:
1495                 case EXPR_COMPOUND_LITERAL: // TODO init?
1496                 case EXPR_SIZEOF:
1497                 case EXPR_CLASSIFY_TYPE:
1498                 case EXPR_ALIGNOF:
1499                 case EXPR_FUNCNAME:
1500                 case EXPR_BUILTIN_CONSTANT_P:
1501                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
1502                 case EXPR_OFFSETOF:
1503                 case EXPR_STATEMENT: // TODO
1504                 case EXPR_LABEL_ADDRESS:
1505                 case EXPR_ENUM_CONSTANT:
1506                         return;
1507         }
1508
1509         panic("unhandled expression");
1510 }
1511
1512 static designator_t *parse_designation(void)
1513 {
1514         designator_t  *result = NULL;
1515         designator_t **anchor = &result;
1516
1517         for (;;) {
1518                 designator_t *designator;
1519                 switch (token.kind) {
1520                 case '[':
1521                         designator = allocate_ast_zero(sizeof(designator[0]));
1522                         designator->source_position = *HERE;
1523                         eat('[');
1524                         add_anchor_token(']');
1525                         designator->array_index = parse_constant_expression();
1526                         rem_anchor_token(']');
1527                         expect(']');
1528                         break;
1529                 case '.':
1530                         designator = allocate_ast_zero(sizeof(designator[0]));
1531                         designator->source_position = *HERE;
1532                         eat('.');
1533                         designator->symbol = expect_identifier("while parsing designator", NULL);
1534                         if (!designator->symbol)
1535                                 return NULL;
1536                         break;
1537                 default:
1538                         expect('=');
1539                         return result;
1540                 }
1541
1542                 assert(designator != NULL);
1543                 *anchor = designator;
1544                 anchor  = &designator->next;
1545         }
1546 }
1547
1548 static initializer_t *initializer_from_string(array_type_t *const type,
1549                                               const string_t *const string)
1550 {
1551         /* TODO: check len vs. size of array type */
1552         (void) type;
1553
1554         initializer_t *initializer = allocate_initializer_zero(INITIALIZER_STRING);
1555         initializer->string.string = *string;
1556
1557         return initializer;
1558 }
1559
1560 static initializer_t *initializer_from_wide_string(array_type_t *const type,
1561                                                    const string_t *const string)
1562 {
1563         /* TODO: check len vs. size of array type */
1564         (void) type;
1565
1566         initializer_t *const initializer =
1567                 allocate_initializer_zero(INITIALIZER_WIDE_STRING);
1568         initializer->wide_string.string = *string;
1569
1570         return initializer;
1571 }
1572
1573 /**
1574  * Build an initializer from a given expression.
1575  */
1576 static initializer_t *initializer_from_expression(type_t *orig_type,
1577                                                   expression_t *expression)
1578 {
1579         /* TODO check that expression is a constant expression */
1580
1581         /* §6.7.8.14/15 char array may be initialized by string literals */
1582         type_t *type           = skip_typeref(orig_type);
1583         type_t *expr_type_orig = expression->base.type;
1584         type_t *expr_type      = skip_typeref(expr_type_orig);
1585
1586         if (is_type_array(type) && expr_type->kind == TYPE_POINTER) {
1587                 array_type_t *const array_type   = &type->array;
1588                 type_t       *const element_type = skip_typeref(array_type->element_type);
1589
1590                 if (element_type->kind == TYPE_ATOMIC) {
1591                         atomic_type_kind_t akind = element_type->atomic.akind;
1592                         switch (expression->kind) {
1593                         case EXPR_STRING_LITERAL:
1594                                 if (akind == ATOMIC_TYPE_CHAR
1595                                                 || akind == ATOMIC_TYPE_SCHAR
1596                                                 || akind == ATOMIC_TYPE_UCHAR) {
1597                                         return initializer_from_string(array_type,
1598                                                         &expression->string_literal.value);
1599                                 }
1600                                 break;
1601
1602                         case EXPR_WIDE_STRING_LITERAL: {
1603                                 type_t *bare_wchar_type = skip_typeref(type_wchar_t);
1604                                 if (get_unqualified_type(element_type) == bare_wchar_type) {
1605                                         return initializer_from_wide_string(array_type,
1606                                                         &expression->string_literal.value);
1607                                 }
1608                                 break;
1609                         }
1610
1611                         default:
1612                                 break;
1613                         }
1614                 }
1615         }
1616
1617         assign_error_t error = semantic_assign(type, expression);
1618         if (error == ASSIGN_ERROR_INCOMPATIBLE)
1619                 return NULL;
1620         report_assign_error(error, type, expression, "initializer",
1621                             &expression->base.source_position);
1622
1623         initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
1624         result->value.value = create_implicit_cast(expression, type);
1625
1626         return result;
1627 }
1628
1629 /**
1630  * Parses an scalar initializer.
1631  *
1632  * §6.7.8.11; eat {} without warning
1633  */
1634 static initializer_t *parse_scalar_initializer(type_t *type,
1635                                                bool must_be_constant)
1636 {
1637         /* there might be extra {} hierarchies */
1638         int braces = 0;
1639         if (token.kind == '{') {
1640                 warningf(WARN_OTHER, HERE, "extra curly braces around scalar initializer");
1641                 do {
1642                         eat('{');
1643                         ++braces;
1644                 } while (token.kind == '{');
1645         }
1646
1647         expression_t *expression = parse_assignment_expression();
1648         mark_vars_read(expression, NULL);
1649         if (must_be_constant && !is_linker_constant(expression)) {
1650                 errorf(&expression->base.source_position,
1651                        "initialisation expression '%E' is not constant",
1652                        expression);
1653         }
1654
1655         initializer_t *initializer = initializer_from_expression(type, expression);
1656
1657         if (initializer == NULL) {
1658                 errorf(&expression->base.source_position,
1659                        "expression '%E' (type '%T') doesn't match expected type '%T'",
1660                        expression, expression->base.type, type);
1661                 /* TODO */
1662                 return NULL;
1663         }
1664
1665         bool additional_warning_displayed = false;
1666         while (braces > 0) {
1667                 next_if(',');
1668                 if (token.kind != '}') {
1669                         if (!additional_warning_displayed) {
1670                                 warningf(WARN_OTHER, HERE, "additional elements in scalar initializer");
1671                                 additional_warning_displayed = true;
1672                         }
1673                 }
1674                 eat_block();
1675                 braces--;
1676         }
1677
1678         return initializer;
1679 }
1680
1681 /**
1682  * An entry in the type path.
1683  */
1684 typedef struct type_path_entry_t type_path_entry_t;
1685 struct type_path_entry_t {
1686         type_t *type;       /**< the upper top type. restored to path->top_tye if this entry is popped. */
1687         union {
1688                 size_t         index;          /**< For array types: the current index. */
1689                 declaration_t *compound_entry; /**< For compound types: the current declaration. */
1690         } v;
1691 };
1692
1693 /**
1694  * A type path expression a position inside compound or array types.
1695  */
1696 typedef struct type_path_t type_path_t;
1697 struct type_path_t {
1698         type_path_entry_t *path;         /**< An flexible array containing the current path. */
1699         type_t            *top_type;     /**< type of the element the path points */
1700         size_t             max_index;    /**< largest index in outermost array */
1701 };
1702
1703 /**
1704  * Prints a type path for debugging.
1705  */
1706 static __attribute__((unused)) void debug_print_type_path(
1707                 const type_path_t *path)
1708 {
1709         size_t len = ARR_LEN(path->path);
1710
1711         for (size_t i = 0; i < len; ++i) {
1712                 const type_path_entry_t *entry = & path->path[i];
1713
1714                 type_t *type = skip_typeref(entry->type);
1715                 if (is_type_compound(type)) {
1716                         /* in gcc mode structs can have no members */
1717                         if (entry->v.compound_entry == NULL) {
1718                                 assert(i == len-1);
1719                                 continue;
1720                         }
1721                         fprintf(stderr, ".%s",
1722                                 entry->v.compound_entry->base.symbol->string);
1723                 } else if (is_type_array(type)) {
1724                         fprintf(stderr, "[%u]", (unsigned) entry->v.index);
1725                 } else {
1726                         fprintf(stderr, "-INVALID-");
1727                 }
1728         }
1729         if (path->top_type != NULL) {
1730                 fprintf(stderr, "  (");
1731                 print_type(path->top_type);
1732                 fprintf(stderr, ")");
1733         }
1734 }
1735
1736 /**
1737  * Return the top type path entry, ie. in a path
1738  * (type).a.b returns the b.
1739  */
1740 static type_path_entry_t *get_type_path_top(const type_path_t *path)
1741 {
1742         size_t len = ARR_LEN(path->path);
1743         assert(len > 0);
1744         return &path->path[len-1];
1745 }
1746
1747 /**
1748  * Enlarge the type path by an (empty) element.
1749  */
1750 static type_path_entry_t *append_to_type_path(type_path_t *path)
1751 {
1752         size_t len = ARR_LEN(path->path);
1753         ARR_RESIZE(type_path_entry_t, path->path, len+1);
1754
1755         type_path_entry_t *result = & path->path[len];
1756         memset(result, 0, sizeof(result[0]));
1757         return result;
1758 }
1759
1760 /**
1761  * Descending into a sub-type. Enter the scope of the current top_type.
1762  */
1763 static void descend_into_subtype(type_path_t *path)
1764 {
1765         type_t *orig_top_type = path->top_type;
1766         type_t *top_type      = skip_typeref(orig_top_type);
1767
1768         type_path_entry_t *top = append_to_type_path(path);
1769         top->type              = top_type;
1770
1771         if (is_type_compound(top_type)) {
1772                 compound_t *const compound = top_type->compound.compound;
1773                 entity_t   *const entry    = skip_unnamed_bitfields(compound->members.entities);
1774
1775                 if (entry != NULL) {
1776                         top->v.compound_entry = &entry->declaration;
1777                         path->top_type = entry->declaration.type;
1778                 } else {
1779                         path->top_type = NULL;
1780                 }
1781         } else if (is_type_array(top_type)) {
1782                 top->v.index   = 0;
1783                 path->top_type = top_type->array.element_type;
1784         } else {
1785                 assert(!is_type_valid(top_type));
1786         }
1787 }
1788
1789 /**
1790  * Pop an entry from the given type path, ie. returning from
1791  * (type).a.b to (type).a
1792  */
1793 static void ascend_from_subtype(type_path_t *path)
1794 {
1795         type_path_entry_t *top = get_type_path_top(path);
1796
1797         path->top_type = top->type;
1798
1799         size_t len = ARR_LEN(path->path);
1800         ARR_RESIZE(type_path_entry_t, path->path, len-1);
1801 }
1802
1803 /**
1804  * Pop entries from the given type path until the given
1805  * path level is reached.
1806  */
1807 static void ascend_to(type_path_t *path, size_t top_path_level)
1808 {
1809         size_t len = ARR_LEN(path->path);
1810
1811         while (len > top_path_level) {
1812                 ascend_from_subtype(path);
1813                 len = ARR_LEN(path->path);
1814         }
1815 }
1816
1817 static bool walk_designator(type_path_t *path, const designator_t *designator,
1818                             bool used_in_offsetof)
1819 {
1820         for (; designator != NULL; designator = designator->next) {
1821                 type_path_entry_t *top       = get_type_path_top(path);
1822                 type_t            *orig_type = top->type;
1823
1824                 type_t *type = skip_typeref(orig_type);
1825
1826                 if (designator->symbol != NULL) {
1827                         symbol_t *symbol = designator->symbol;
1828                         if (!is_type_compound(type)) {
1829                                 if (is_type_valid(type)) {
1830                                         errorf(&designator->source_position,
1831                                                "'.%Y' designator used for non-compound type '%T'",
1832                                                symbol, orig_type);
1833                                 }
1834
1835                                 top->type             = type_error_type;
1836                                 top->v.compound_entry = NULL;
1837                                 orig_type             = type_error_type;
1838                         } else {
1839                                 compound_t *compound = type->compound.compound;
1840                                 entity_t   *iter     = compound->members.entities;
1841                                 for (; iter != NULL; iter = iter->base.next) {
1842                                         if (iter->base.symbol == symbol) {
1843                                                 break;
1844                                         }
1845                                 }
1846                                 if (iter == NULL) {
1847                                         errorf(&designator->source_position,
1848                                                "'%T' has no member named '%Y'", orig_type, symbol);
1849                                         return false;
1850                                 }
1851                                 assert(iter->kind == ENTITY_COMPOUND_MEMBER);
1852                                 if (used_in_offsetof && iter->compound_member.bitfield) {
1853                                         errorf(&designator->source_position,
1854                                                    "offsetof designator '%Y' must not specify bitfield",
1855                                                    symbol);
1856                                         return false;
1857                                 }
1858
1859                                 top->type             = orig_type;
1860                                 top->v.compound_entry = &iter->declaration;
1861                                 orig_type             = iter->declaration.type;
1862                         }
1863                 } else {
1864                         expression_t *array_index = designator->array_index;
1865                         if (is_constant_expression(array_index) != EXPR_CLASS_CONSTANT)
1866                                 return true;
1867
1868                         if (!is_type_array(type)) {
1869                                 if (is_type_valid(type)) {
1870                                         errorf(&designator->source_position,
1871                                                "[%E] designator used for non-array type '%T'",
1872                                                array_index, orig_type);
1873                                 }
1874                                 return false;
1875                         }
1876
1877                         long index = fold_constant_to_int(array_index);
1878                         if (!used_in_offsetof) {
1879                                 if (index < 0) {
1880                                         errorf(&designator->source_position,
1881                                                "array index [%E] must be positive", array_index);
1882                                 } else if (type->array.size_constant) {
1883                                         long array_size = type->array.size;
1884                                         if (index >= array_size) {
1885                                                 errorf(&designator->source_position,
1886                                                        "designator [%E] (%d) exceeds array size %d",
1887                                                        array_index, index, array_size);
1888                                         }
1889                                 }
1890                         }
1891
1892                         top->type    = orig_type;
1893                         top->v.index = (size_t) index;
1894                         orig_type    = type->array.element_type;
1895                 }
1896                 path->top_type = orig_type;
1897
1898                 if (designator->next != NULL) {
1899                         descend_into_subtype(path);
1900                 }
1901         }
1902         return true;
1903 }
1904
1905 static void advance_current_object(type_path_t *path, size_t top_path_level)
1906 {
1907         type_path_entry_t *top = get_type_path_top(path);
1908
1909         type_t *type = skip_typeref(top->type);
1910         if (is_type_union(type)) {
1911                 /* in unions only the first element is initialized */
1912                 top->v.compound_entry = NULL;
1913         } else if (is_type_struct(type)) {
1914                 declaration_t *entry = top->v.compound_entry;
1915
1916                 entity_t *const next_entity = skip_unnamed_bitfields(entry->base.next);
1917                 if (next_entity != NULL) {
1918                         assert(is_declaration(next_entity));
1919                         entry = &next_entity->declaration;
1920                 } else {
1921                         entry = NULL;
1922                 }
1923
1924                 top->v.compound_entry = entry;
1925                 if (entry != NULL) {
1926                         path->top_type = entry->type;
1927                         return;
1928                 }
1929         } else if (is_type_array(type)) {
1930                 assert(is_type_array(type));
1931
1932                 top->v.index++;
1933
1934                 if (!type->array.size_constant || top->v.index < type->array.size) {
1935                         return;
1936                 }
1937         } else {
1938                 assert(!is_type_valid(type));
1939                 return;
1940         }
1941
1942         /* we're past the last member of the current sub-aggregate, try if we
1943          * can ascend in the type hierarchy and continue with another subobject */
1944         size_t len = ARR_LEN(path->path);
1945
1946         if (len > top_path_level) {
1947                 ascend_from_subtype(path);
1948                 advance_current_object(path, top_path_level);
1949         } else {
1950                 path->top_type = NULL;
1951         }
1952 }
1953
1954 /**
1955  * skip any {...} blocks until a closing bracket is reached.
1956  */
1957 static void skip_initializers(void)
1958 {
1959         next_if('{');
1960
1961         while (token.kind != '}') {
1962                 if (token.kind == T_EOF)
1963                         return;
1964                 if (token.kind == '{') {
1965                         eat_block();
1966                         continue;
1967                 }
1968                 next_token();
1969         }
1970 }
1971
1972 static initializer_t *create_empty_initializer(void)
1973 {
1974         static initializer_t empty_initializer
1975                 = { .list = { { INITIALIZER_LIST }, 0 } };
1976         return &empty_initializer;
1977 }
1978
1979 /**
1980  * Parse a part of an initialiser for a struct or union,
1981  */
1982 static initializer_t *parse_sub_initializer(type_path_t *path,
1983                 type_t *outer_type, size_t top_path_level,
1984                 parse_initializer_env_t *env)
1985 {
1986         if (token.kind == '}') {
1987                 /* empty initializer */
1988                 return create_empty_initializer();
1989         }
1990
1991         type_t *orig_type = path->top_type;
1992         type_t *type      = NULL;
1993
1994         if (orig_type == NULL) {
1995                 /* We are initializing an empty compound. */
1996         } else {
1997                 type = skip_typeref(orig_type);
1998         }
1999
2000         initializer_t **initializers = NEW_ARR_F(initializer_t*, 0);
2001
2002         while (true) {
2003                 designator_t *designator = NULL;
2004                 if (token.kind == '.' || token.kind == '[') {
2005                         designator = parse_designation();
2006                         goto finish_designator;
2007                 } else if (token.kind == T_IDENTIFIER && look_ahead(1)->kind == ':') {
2008                         /* GNU-style designator ("identifier: value") */
2009                         designator = allocate_ast_zero(sizeof(designator[0]));
2010                         designator->source_position = *HERE;
2011                         designator->symbol          = token.base.symbol;
2012                         eat(T_IDENTIFIER);
2013                         eat(':');
2014
2015 finish_designator:
2016                         /* reset path to toplevel, evaluate designator from there */
2017                         ascend_to(path, top_path_level);
2018                         if (!walk_designator(path, designator, false)) {
2019                                 /* can't continue after designation error */
2020                                 goto end_error;
2021                         }
2022
2023                         initializer_t *designator_initializer
2024                                 = allocate_initializer_zero(INITIALIZER_DESIGNATOR);
2025                         designator_initializer->designator.designator = designator;
2026                         ARR_APP1(initializer_t*, initializers, designator_initializer);
2027
2028                         orig_type = path->top_type;
2029                         type      = orig_type != NULL ? skip_typeref(orig_type) : NULL;
2030                 }
2031
2032                 initializer_t *sub;
2033
2034                 if (token.kind == '{') {
2035                         if (type != NULL && is_type_scalar(type)) {
2036                                 sub = parse_scalar_initializer(type, env->must_be_constant);
2037                         } else {
2038                                 if (type == NULL) {
2039                                         if (env->entity != NULL) {
2040                                                 errorf(HERE, "extra brace group at end of initializer for '%N'", env->entity);
2041                                         } else {
2042                                                 errorf(HERE, "extra brace group at end of initializer");
2043                                         }
2044                                         eat('{');
2045                                 } else {
2046                                         eat('{');
2047                                         descend_into_subtype(path);
2048                                 }
2049
2050                                 add_anchor_token('}');
2051                                 sub = parse_sub_initializer(path, orig_type, top_path_level+1,
2052                                                             env);
2053                                 rem_anchor_token('}');
2054
2055                                 expect('}');
2056
2057                                 if (!type)
2058                                         goto error_parse_next;
2059
2060                                 ascend_from_subtype(path);
2061                         }
2062                 } else {
2063                         /* must be an expression */
2064                         expression_t *expression = parse_assignment_expression();
2065                         mark_vars_read(expression, NULL);
2066
2067                         if (env->must_be_constant && !is_linker_constant(expression)) {
2068                                 errorf(&expression->base.source_position,
2069                                        "Initialisation expression '%E' is not constant",
2070                                        expression);
2071                         }
2072
2073                         if (type == NULL) {
2074                                 /* we are already outside, ... */
2075                                 if (outer_type == NULL)
2076                                         goto error_parse_next;
2077                                 type_t *const outer_type_skip = skip_typeref(outer_type);
2078                                 if (is_type_compound(outer_type_skip) &&
2079                                                 !outer_type_skip->compound.compound->complete) {
2080                                         goto error_parse_next;
2081                                 }
2082
2083                                 source_position_t const* const pos = &expression->base.source_position;
2084                                 if (env->entity != NULL) {
2085                                         warningf(WARN_OTHER, pos, "excess elements in initializer for '%N'", env->entity);
2086                                 } else {
2087                                         warningf(WARN_OTHER, pos, "excess elements in initializer");
2088                                 }
2089                                 goto error_parse_next;
2090                         }
2091
2092                         /* handle { "string" } special case */
2093                         if ((expression->kind == EXPR_STRING_LITERAL
2094                                         || expression->kind == EXPR_WIDE_STRING_LITERAL)
2095                                         && outer_type != NULL) {
2096                                 sub = initializer_from_expression(outer_type, expression);
2097                                 if (sub != NULL) {
2098                                         next_if(',');
2099                                         if (token.kind != '}') {
2100                                                 warningf(WARN_OTHER, HERE, "excessive elements in initializer for type '%T'", orig_type);
2101                                         }
2102                                         /* TODO: eat , ... */
2103                                         return sub;
2104                                 }
2105                         }
2106
2107                         /* descend into subtypes until expression matches type */
2108                         while (true) {
2109                                 orig_type = path->top_type;
2110                                 type      = skip_typeref(orig_type);
2111
2112                                 sub = initializer_from_expression(orig_type, expression);
2113                                 if (sub != NULL) {
2114                                         break;
2115                                 }
2116                                 if (!is_type_valid(type)) {
2117                                         goto end_error;
2118                                 }
2119                                 if (is_type_scalar(type)) {
2120                                         errorf(&expression->base.source_position,
2121                                                         "expression '%E' doesn't match expected type '%T'",
2122                                                         expression, orig_type);
2123                                         goto end_error;
2124                                 }
2125
2126                                 descend_into_subtype(path);
2127                         }
2128                 }
2129
2130                 /* update largest index of top array */
2131                 const type_path_entry_t *first      = &path->path[0];
2132                 type_t                  *first_type = first->type;
2133                 first_type                          = skip_typeref(first_type);
2134                 if (is_type_array(first_type)) {
2135                         size_t index = first->v.index;
2136                         if (index > path->max_index)
2137                                 path->max_index = index;
2138                 }
2139
2140                 /* append to initializers list */
2141                 ARR_APP1(initializer_t*, initializers, sub);
2142
2143 error_parse_next:
2144                 if (token.kind == '}') {
2145                         break;
2146                 }
2147                 add_anchor_token('}');
2148                 expect(',');
2149                 rem_anchor_token('}');
2150                 if (token.kind == '}') {
2151                         break;
2152                 }
2153
2154                 if (type != NULL) {
2155                         /* advance to the next declaration if we are not at the end */
2156                         advance_current_object(path, top_path_level);
2157                         orig_type = path->top_type;
2158                         if (orig_type != NULL)
2159                                 type = skip_typeref(orig_type);
2160                         else
2161                                 type = NULL;
2162                 }
2163         }
2164
2165         size_t len  = ARR_LEN(initializers);
2166         size_t size = sizeof(initializer_list_t) + len * sizeof(initializers[0]);
2167         initializer_t *result = allocate_ast_zero(size);
2168         result->kind          = INITIALIZER_LIST;
2169         result->list.len      = len;
2170         memcpy(&result->list.initializers, initializers,
2171                len * sizeof(initializers[0]));
2172
2173         DEL_ARR_F(initializers);
2174         ascend_to(path, top_path_level+1);
2175
2176         return result;
2177
2178 end_error:
2179         skip_initializers();
2180         DEL_ARR_F(initializers);
2181         ascend_to(path, top_path_level+1);
2182         return NULL;
2183 }
2184
2185 static expression_t *make_size_literal(size_t value)
2186 {
2187         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_INTEGER);
2188         literal->base.type    = type_size_t;
2189
2190         char buf[128];
2191         snprintf(buf, sizeof(buf), "%u", (unsigned) value);
2192         literal->literal.value = make_string(buf);
2193
2194         return literal;
2195 }
2196
2197 /**
2198  * Parses an initializer. Parsers either a compound literal
2199  * (env->declaration == NULL) or an initializer of a declaration.
2200  */
2201 static initializer_t *parse_initializer(parse_initializer_env_t *env)
2202 {
2203         type_t        *type      = skip_typeref(env->type);
2204         size_t         max_index = 0;
2205         initializer_t *result;
2206
2207         if (is_type_scalar(type)) {
2208                 result = parse_scalar_initializer(type, env->must_be_constant);
2209         } else if (token.kind == '{') {
2210                 eat('{');
2211
2212                 type_path_t path;
2213                 memset(&path, 0, sizeof(path));
2214                 path.top_type = env->type;
2215                 path.path     = NEW_ARR_F(type_path_entry_t, 0);
2216
2217                 descend_into_subtype(&path);
2218
2219                 add_anchor_token('}');
2220                 result = parse_sub_initializer(&path, env->type, 1, env);
2221                 rem_anchor_token('}');
2222
2223                 max_index = path.max_index;
2224                 DEL_ARR_F(path.path);
2225
2226                 expect('}');
2227         } else {
2228                 /* parse_scalar_initializer() also works in this case: we simply
2229                  * have an expression without {} around it */
2230                 result = parse_scalar_initializer(type, env->must_be_constant);
2231         }
2232
2233         /* §6.7.8:22 array initializers for arrays with unknown size determine
2234          * the array type size */
2235         if (is_type_array(type) && type->array.size_expression == NULL
2236                         && result != NULL) {
2237                 size_t size;
2238                 switch (result->kind) {
2239                 case INITIALIZER_LIST:
2240                         assert(max_index != 0xdeadbeaf);
2241                         size = max_index + 1;
2242                         break;
2243
2244                 case INITIALIZER_STRING:
2245                         size = result->string.string.size;
2246                         break;
2247
2248                 case INITIALIZER_WIDE_STRING:
2249                         size = result->wide_string.string.size;
2250                         break;
2251
2252                 case INITIALIZER_DESIGNATOR:
2253                 case INITIALIZER_VALUE:
2254                         /* can happen for parse errors */
2255                         size = 0;
2256                         break;
2257
2258                 default:
2259                         internal_errorf(HERE, "invalid initializer type");
2260                 }
2261
2262                 type_t *new_type = duplicate_type(type);
2263
2264                 new_type->array.size_expression   = make_size_literal(size);
2265                 new_type->array.size_constant     = true;
2266                 new_type->array.has_implicit_size = true;
2267                 new_type->array.size              = size;
2268                 env->type = new_type;
2269         }
2270
2271         return result;
2272 }
2273
2274 static void append_entity(scope_t *scope, entity_t *entity)
2275 {
2276         if (scope->last_entity != NULL) {
2277                 scope->last_entity->base.next = entity;
2278         } else {
2279                 scope->entities = entity;
2280         }
2281         entity->base.parent_entity = current_entity;
2282         scope->last_entity         = entity;
2283 }
2284
2285
2286 static compound_t *parse_compound_type_specifier(bool is_struct)
2287 {
2288         source_position_t const pos = *HERE;
2289         eat(is_struct ? T_struct : T_union);
2290
2291         symbol_t    *symbol     = NULL;
2292         entity_t    *entity     = NULL;
2293         attribute_t *attributes = NULL;
2294
2295         if (token.kind == T___attribute__) {
2296                 attributes = parse_attributes(NULL);
2297         }
2298
2299         entity_kind_tag_t const kind = is_struct ? ENTITY_STRUCT : ENTITY_UNION;
2300         if (token.kind == T_IDENTIFIER) {
2301                 /* the compound has a name, check if we have seen it already */
2302                 symbol = token.base.symbol;
2303                 entity = get_tag(symbol, kind);
2304                 eat(T_IDENTIFIER);
2305
2306                 if (entity != NULL) {
2307                         if (entity->base.parent_scope != current_scope &&
2308                             (token.kind == '{' || token.kind == ';')) {
2309                                 /* we're in an inner scope and have a definition. Shadow
2310                                  * existing definition in outer scope */
2311                                 entity = NULL;
2312                         } else if (entity->compound.complete && token.kind == '{') {
2313                                 source_position_t const *const ppos = &entity->base.source_position;
2314                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2315                                 /* clear members in the hope to avoid further errors */
2316                                 entity->compound.members.entities = NULL;
2317                         }
2318                 }
2319         } else if (token.kind != '{') {
2320                 char const *const msg =
2321                         is_struct ? "while parsing struct type specifier" :
2322                                     "while parsing union type specifier";
2323                 parse_error_expected(msg, T_IDENTIFIER, '{', NULL);
2324
2325                 return NULL;
2326         }
2327
2328         if (entity == NULL) {
2329                 entity = allocate_entity_zero(kind, NAMESPACE_TAG, symbol, &pos);
2330                 entity->compound.alignment = 1;
2331                 entity->base.parent_scope  = current_scope;
2332                 if (symbol != NULL) {
2333                         environment_push(entity);
2334                 }
2335                 append_entity(current_scope, entity);
2336         }
2337
2338         if (token.kind == '{') {
2339                 parse_compound_type_entries(&entity->compound);
2340
2341                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2342                 if (symbol == NULL) {
2343                         assert(anonymous_entity == NULL);
2344                         anonymous_entity = entity;
2345                 }
2346         }
2347
2348         if (attributes != NULL) {
2349                 handle_entity_attributes(attributes, entity);
2350         }
2351
2352         return &entity->compound;
2353 }
2354
2355 static void parse_enum_entries(type_t *const enum_type)
2356 {
2357         eat('{');
2358
2359         if (token.kind == '}') {
2360                 errorf(HERE, "empty enum not allowed");
2361                 eat('}');
2362                 return;
2363         }
2364
2365         add_anchor_token('}');
2366         add_anchor_token(',');
2367         do {
2368                 add_anchor_token('=');
2369                 source_position_t pos;
2370                 symbol_t *const symbol = expect_identifier("while parsing enum entry", &pos);
2371                 entity_t *const entity = allocate_entity_zero(ENTITY_ENUM_VALUE, NAMESPACE_NORMAL, symbol, &pos);
2372                 entity->enum_value.enum_type = enum_type;
2373                 rem_anchor_token('=');
2374
2375                 if (next_if('=')) {
2376                         expression_t *value = parse_constant_expression();
2377
2378                         value = create_implicit_cast(value, enum_type);
2379                         entity->enum_value.value = value;
2380
2381                         /* TODO semantic */
2382                 }
2383
2384                 record_entity(entity, false);
2385         } while (next_if(',') && token.kind != '}');
2386         rem_anchor_token(',');
2387         rem_anchor_token('}');
2388
2389         expect('}');
2390 }
2391
2392 static type_t *parse_enum_specifier(void)
2393 {
2394         source_position_t const pos = *HERE;
2395         entity_t               *entity;
2396         symbol_t               *symbol;
2397
2398         eat(T_enum);
2399         switch (token.kind) {
2400                 case T_IDENTIFIER:
2401                         symbol = token.base.symbol;
2402                         entity = get_tag(symbol, ENTITY_ENUM);
2403                         eat(T_IDENTIFIER);
2404
2405                         if (entity != NULL) {
2406                                 if (entity->base.parent_scope != current_scope &&
2407                                                 (token.kind == '{' || token.kind == ';')) {
2408                                         /* we're in an inner scope and have a definition. Shadow
2409                                          * existing definition in outer scope */
2410                                         entity = NULL;
2411                                 } else if (entity->enume.complete && token.kind == '{') {
2412                                         source_position_t const *const ppos = &entity->base.source_position;
2413                                         errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2414                                 }
2415                         }
2416                         break;
2417
2418                 case '{':
2419                         entity = NULL;
2420                         symbol = NULL;
2421                         break;
2422
2423                 default:
2424                         parse_error_expected("while parsing enum type specifier",
2425                                         T_IDENTIFIER, '{', NULL);
2426                         return NULL;
2427         }
2428
2429         if (entity == NULL) {
2430                 entity = allocate_entity_zero(ENTITY_ENUM, NAMESPACE_TAG, symbol, &pos);
2431                 entity->base.parent_scope = current_scope;
2432         }
2433
2434         type_t *const type     = allocate_type_zero(TYPE_ENUM);
2435         type->enumt.enume      = &entity->enume;
2436         type->enumt.base.akind = ATOMIC_TYPE_INT;
2437
2438         if (token.kind == '{') {
2439                 if (symbol != NULL) {
2440                         environment_push(entity);
2441                 }
2442                 append_entity(current_scope, entity);
2443                 entity->enume.complete = true;
2444
2445                 parse_enum_entries(type);
2446                 parse_attributes(NULL);
2447
2448                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2449                 if (symbol == NULL) {
2450                         assert(anonymous_entity == NULL);
2451                         anonymous_entity = entity;
2452                 }
2453         } else if (!entity->enume.complete && !(c_mode & _GNUC)) {
2454                 errorf(HERE, "'%T' used before definition (incomplete enums are a GNU extension)", type);
2455         }
2456
2457         return type;
2458 }
2459
2460 /**
2461  * if a symbol is a typedef to another type, return true
2462  */
2463 static bool is_typedef_symbol(symbol_t *symbol)
2464 {
2465         const entity_t *const entity = get_entity(symbol, NAMESPACE_NORMAL);
2466         return entity != NULL && entity->kind == ENTITY_TYPEDEF;
2467 }
2468
2469 static type_t *parse_typeof(void)
2470 {
2471         eat(T___typeof__);
2472
2473         type_t *type;
2474
2475         add_anchor_token(')');
2476         expect('(');
2477
2478         expression_t *expression  = NULL;
2479
2480         switch (token.kind) {
2481         case T_IDENTIFIER:
2482                 if (is_typedef_symbol(token.base.symbol)) {
2483         DECLARATION_START
2484                         type = parse_typename();
2485                 } else {
2486         default:
2487                         expression = parse_expression();
2488                         type       = revert_automatic_type_conversion(expression);
2489                 }
2490                 break;
2491         }
2492
2493         rem_anchor_token(')');
2494         expect(')');
2495
2496         type_t *typeof_type              = allocate_type_zero(TYPE_TYPEOF);
2497         typeof_type->typeoft.expression  = expression;
2498         typeof_type->typeoft.typeof_type = type;
2499
2500         return typeof_type;
2501 }
2502
2503 typedef enum specifiers_t {
2504         SPECIFIER_SIGNED    = 1 << 0,
2505         SPECIFIER_UNSIGNED  = 1 << 1,
2506         SPECIFIER_LONG      = 1 << 2,
2507         SPECIFIER_INT       = 1 << 3,
2508         SPECIFIER_DOUBLE    = 1 << 4,
2509         SPECIFIER_CHAR      = 1 << 5,
2510         SPECIFIER_WCHAR_T   = 1 << 6,
2511         SPECIFIER_SHORT     = 1 << 7,
2512         SPECIFIER_LONG_LONG = 1 << 8,
2513         SPECIFIER_FLOAT     = 1 << 9,
2514         SPECIFIER_BOOL      = 1 << 10,
2515         SPECIFIER_VOID      = 1 << 11,
2516         SPECIFIER_INT8      = 1 << 12,
2517         SPECIFIER_INT16     = 1 << 13,
2518         SPECIFIER_INT32     = 1 << 14,
2519         SPECIFIER_INT64     = 1 << 15,
2520         SPECIFIER_INT128    = 1 << 16,
2521         SPECIFIER_COMPLEX   = 1 << 17,
2522         SPECIFIER_IMAGINARY = 1 << 18,
2523 } specifiers_t;
2524
2525 static type_t *get_typedef_type(symbol_t *symbol)
2526 {
2527         entity_t *entity = get_entity(symbol, NAMESPACE_NORMAL);
2528         if (entity == NULL || entity->kind != ENTITY_TYPEDEF)
2529                 return NULL;
2530
2531         type_t *type            = allocate_type_zero(TYPE_TYPEDEF);
2532         type->typedeft.typedefe = &entity->typedefe;
2533
2534         return type;
2535 }
2536
2537 static attribute_t *parse_attribute_ms_property(attribute_t *attribute)
2538 {
2539         attribute_property_argument_t *const property = allocate_ast_zero(sizeof(*property));
2540
2541         add_anchor_token(')');
2542         add_anchor_token(',');
2543         expect('(');
2544
2545         do {
2546                 add_anchor_token('=');
2547                 source_position_t pos;
2548                 symbol_t *const prop_sym = expect_identifier("while parsing property declspec", &pos);
2549                 rem_anchor_token('=');
2550
2551                 symbol_t **prop = NULL;
2552                 if (prop_sym) {
2553                         if (streq(prop_sym->string, "put")) {
2554                                 prop = &property->put_symbol;
2555                         } else if (streq(prop_sym->string, "get")) {
2556                                 prop = &property->get_symbol;
2557                         } else {
2558                                 errorf(&pos, "expected put or get in property declspec, but got '%Y'", prop_sym);
2559                         }
2560                 }
2561
2562                 add_anchor_token(T_IDENTIFIER);
2563                 expect('=');
2564                 rem_anchor_token(T_IDENTIFIER);
2565
2566                 symbol_t *const sym = expect_identifier("while parsing property declspec", NULL);
2567                 if (prop != NULL)
2568                         *prop = sym ? sym : sym_anonymous;
2569         } while (next_if(','));
2570         rem_anchor_token(',');
2571         rem_anchor_token(')');
2572
2573         attribute->a.property = property;
2574
2575         expect(')');
2576         return attribute;
2577 }
2578
2579 static attribute_t *parse_microsoft_extended_decl_modifier_single(void)
2580 {
2581         attribute_kind_t kind = ATTRIBUTE_UNKNOWN;
2582         if (next_if(T_restrict)) {
2583                 kind = ATTRIBUTE_MS_RESTRICT;
2584         } else if (token.kind == T_IDENTIFIER) {
2585                 char const *const name = token.base.symbol->string;
2586                 for (attribute_kind_t k = ATTRIBUTE_MS_FIRST; k <= ATTRIBUTE_MS_LAST;
2587                      ++k) {
2588                         const char *attribute_name = get_attribute_name(k);
2589                         if (attribute_name != NULL && streq(attribute_name, name)) {
2590                                 kind = k;
2591                                 break;
2592                         }
2593                 }
2594
2595                 if (kind == ATTRIBUTE_UNKNOWN) {
2596                         warningf(WARN_ATTRIBUTE, HERE, "unknown __declspec '%s' ignored", name);
2597                 }
2598         } else {
2599                 parse_error_expected("while parsing __declspec", T_IDENTIFIER, NULL);
2600                 return NULL;
2601         }
2602
2603         attribute_t *attribute = allocate_attribute_zero(kind);
2604         eat(T_IDENTIFIER);
2605
2606         if (kind == ATTRIBUTE_MS_PROPERTY) {
2607                 return parse_attribute_ms_property(attribute);
2608         }
2609
2610         /* parse arguments */
2611         if (next_if('('))
2612                 attribute->a.arguments = parse_attribute_arguments();
2613
2614         return attribute;
2615 }
2616
2617 static attribute_t *parse_microsoft_extended_decl_modifier(attribute_t *first)
2618 {
2619         eat(T__declspec);
2620
2621         add_anchor_token(')');
2622         expect('(');
2623         if (token.kind != ')') {
2624                 attribute_t **anchor = &first;
2625                 do {
2626                         while (*anchor != NULL)
2627                                 anchor = &(*anchor)->next;
2628
2629                         attribute_t *attribute
2630                                 = parse_microsoft_extended_decl_modifier_single();
2631                         if (attribute == NULL)
2632                                 break;
2633
2634                         *anchor = attribute;
2635                         anchor  = &attribute->next;
2636                 } while (next_if(','));
2637         }
2638         rem_anchor_token(')');
2639         expect(')');
2640         return first;
2641 }
2642
2643 static entity_t *create_error_entity(symbol_t *symbol, entity_kind_tag_t kind)
2644 {
2645         entity_t *const entity = allocate_entity_zero(kind, NAMESPACE_NORMAL, symbol, HERE);
2646         if (is_declaration(entity)) {
2647                 entity->declaration.type     = type_error_type;
2648                 entity->declaration.implicit = true;
2649         } else if (kind == ENTITY_TYPEDEF) {
2650                 entity->typedefe.type    = type_error_type;
2651                 entity->typedefe.builtin = true;
2652         }
2653         if (kind != ENTITY_COMPOUND_MEMBER)
2654                 record_entity(entity, false);
2655         return entity;
2656 }
2657
2658 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
2659 {
2660         type_t            *type            = NULL;
2661         type_qualifiers_t  qualifiers      = TYPE_QUALIFIER_NONE;
2662         unsigned           type_specifiers = 0;
2663         bool               newtype         = false;
2664         bool               saw_error       = false;
2665
2666         memset(specifiers, 0, sizeof(*specifiers));
2667         specifiers->source_position = *HERE;
2668
2669         while (true) {
2670                 specifiers->attributes = parse_attributes(specifiers->attributes);
2671
2672                 switch (token.kind) {
2673                 /* storage class */
2674 #define MATCH_STORAGE_CLASS(token, class)                                  \
2675                 case token:                                                        \
2676                         if (specifiers->storage_class != STORAGE_CLASS_NONE) {         \
2677                                 errorf(HERE, "multiple storage classes in declaration specifiers"); \
2678                         }                                                              \
2679                         specifiers->storage_class = class;                             \
2680                         if (specifiers->thread_local)                                  \
2681                                 goto check_thread_storage_class;                           \
2682                         eat(token); \
2683                         break;
2684
2685                 MATCH_STORAGE_CLASS(T_typedef,  STORAGE_CLASS_TYPEDEF)
2686                 MATCH_STORAGE_CLASS(T_extern,   STORAGE_CLASS_EXTERN)
2687                 MATCH_STORAGE_CLASS(T_static,   STORAGE_CLASS_STATIC)
2688                 MATCH_STORAGE_CLASS(T_auto,     STORAGE_CLASS_AUTO)
2689                 MATCH_STORAGE_CLASS(T_register, STORAGE_CLASS_REGISTER)
2690
2691                 case T__declspec:
2692                         specifiers->attributes
2693                                 = parse_microsoft_extended_decl_modifier(specifiers->attributes);
2694                         break;
2695
2696                 case T___thread:
2697                         if (specifiers->thread_local) {
2698                                 errorf(HERE, "duplicate '__thread'");
2699                         } else {
2700                                 specifiers->thread_local = true;
2701 check_thread_storage_class:
2702                                 switch (specifiers->storage_class) {
2703                                         case STORAGE_CLASS_EXTERN:
2704                                         case STORAGE_CLASS_NONE:
2705                                         case STORAGE_CLASS_STATIC:
2706                                                 break;
2707
2708                                                 char const* wrong;
2709                                         case STORAGE_CLASS_AUTO:     wrong = "auto";     goto wrong_thread_storage_class;
2710                                         case STORAGE_CLASS_REGISTER: wrong = "register"; goto wrong_thread_storage_class;
2711                                         case STORAGE_CLASS_TYPEDEF:  wrong = "typedef";  goto wrong_thread_storage_class;
2712 wrong_thread_storage_class:
2713                                                 errorf(HERE, "'__thread' used with '%s'", wrong);
2714                                                 break;
2715                                 }
2716                         }
2717                         next_token();
2718                         break;
2719
2720                 /* type qualifiers */
2721 #define MATCH_TYPE_QUALIFIER(token, qualifier)                          \
2722                 case token:                                                     \
2723                         qualifiers |= qualifier;                                    \
2724                         eat(token); \
2725                         break
2726
2727                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
2728                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
2729                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
2730                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
2731                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
2732                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
2733                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
2734                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
2735
2736                 /* type specifiers */
2737 #define MATCH_SPECIFIER(token, specifier, name)                         \
2738                 case token:                                                     \
2739                         if (type_specifiers & specifier) {                           \
2740                                 errorf(HERE, "multiple " name " type specifiers given"); \
2741                         } else {                                                    \
2742                                 type_specifiers |= specifier;                           \
2743                         }                                                           \
2744                         eat(token); \
2745                         break
2746
2747                 MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool");
2748                 MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex");
2749                 MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary");
2750                 MATCH_SPECIFIER(T__int128,    SPECIFIER_INT128,    "_int128");
2751                 MATCH_SPECIFIER(T__int16,     SPECIFIER_INT16,     "_int16");
2752                 MATCH_SPECIFIER(T__int32,     SPECIFIER_INT32,     "_int32");
2753                 MATCH_SPECIFIER(T__int64,     SPECIFIER_INT64,     "_int64");
2754                 MATCH_SPECIFIER(T__int8,      SPECIFIER_INT8,      "_int8");
2755                 MATCH_SPECIFIER(T_bool,       SPECIFIER_BOOL,      "bool");
2756                 MATCH_SPECIFIER(T_char,       SPECIFIER_CHAR,      "char");
2757                 MATCH_SPECIFIER(T_double,     SPECIFIER_DOUBLE,    "double");
2758                 MATCH_SPECIFIER(T_float,      SPECIFIER_FLOAT,     "float");
2759                 MATCH_SPECIFIER(T_int,        SPECIFIER_INT,       "int");
2760                 MATCH_SPECIFIER(T_short,      SPECIFIER_SHORT,     "short");
2761                 MATCH_SPECIFIER(T_signed,     SPECIFIER_SIGNED,    "signed");
2762                 MATCH_SPECIFIER(T_unsigned,   SPECIFIER_UNSIGNED,  "unsigned");
2763                 MATCH_SPECIFIER(T_void,       SPECIFIER_VOID,      "void");
2764                 MATCH_SPECIFIER(T_wchar_t,    SPECIFIER_WCHAR_T,   "wchar_t");
2765
2766                 case T_inline:
2767                         eat(T_inline);
2768                         specifiers->is_inline = true;
2769                         break;
2770
2771 #if 0
2772                 case T__forceinline:
2773                         eat(T__forceinline);
2774                         specifiers->modifiers |= DM_FORCEINLINE;
2775                         break;
2776 #endif
2777
2778                 case T_long:
2779                         if (type_specifiers & SPECIFIER_LONG_LONG) {
2780                                 errorf(HERE, "too many long type specifiers given");
2781                         } else if (type_specifiers & SPECIFIER_LONG) {
2782                                 type_specifiers |= SPECIFIER_LONG_LONG;
2783                         } else {
2784                                 type_specifiers |= SPECIFIER_LONG;
2785                         }
2786                         eat(T_long);
2787                         break;
2788
2789 #define CHECK_DOUBLE_TYPE() \
2790         (type != NULL ? errorf(HERE, "multiple types in declaration specifiers") : (void)0)
2791
2792                 case T_struct:
2793                         CHECK_DOUBLE_TYPE();
2794                         type = allocate_type_zero(TYPE_COMPOUND_STRUCT);
2795
2796                         type->compound.compound = parse_compound_type_specifier(true);
2797                         break;
2798                 case T_union:
2799                         CHECK_DOUBLE_TYPE();
2800                         type = allocate_type_zero(TYPE_COMPOUND_UNION);
2801                         type->compound.compound = parse_compound_type_specifier(false);
2802                         break;
2803                 case T_enum:
2804                         CHECK_DOUBLE_TYPE();
2805                         type = parse_enum_specifier();
2806                         break;
2807                 case T___typeof__:
2808                         CHECK_DOUBLE_TYPE();
2809                         type = parse_typeof();
2810                         break;
2811                 case T___builtin_va_list:
2812                         CHECK_DOUBLE_TYPE();
2813                         type = duplicate_type(type_valist);
2814                         eat(T___builtin_va_list);
2815                         break;
2816
2817                 case T_IDENTIFIER: {
2818                         /* only parse identifier if we haven't found a type yet */
2819                         if (type != NULL || type_specifiers != 0) {
2820                                 /* Be somewhat resilient to typos like 'unsigned lng* f()' in a
2821                                  * declaration, so it doesn't generate errors about expecting '(' or
2822                                  * '{' later on. */
2823                                 switch (look_ahead(1)->kind) {
2824                                         STORAGE_CLASSES
2825                                         TYPE_SPECIFIERS
2826                                         case T_const:
2827                                         case T_restrict:
2828                                         case T_volatile:
2829                                         case T_inline:
2830                                         case T__forceinline: /* ^ DECLARATION_START except for __attribute__ */
2831                                         case T_IDENTIFIER:
2832                                         case '&':
2833                                         case '*':
2834                                                 errorf(HERE, "discarding stray %K in declaration specifier", &token);
2835                                                 eat(T_IDENTIFIER);
2836                                                 continue;
2837
2838                                         default:
2839                                                 goto finish_specifiers;
2840                                 }
2841                         }
2842
2843                         type_t *const typedef_type = get_typedef_type(token.base.symbol);
2844                         if (typedef_type == NULL) {
2845                                 /* Be somewhat resilient to typos like 'vodi f()' at the beginning of a
2846                                  * declaration, so it doesn't generate 'implicit int' followed by more
2847                                  * errors later on. */
2848                                 token_kind_t const la1_type = (token_kind_t)look_ahead(1)->kind;
2849                                 switch (la1_type) {
2850                                         DECLARATION_START
2851                                         case T_IDENTIFIER:
2852                                         case '&':
2853                                         case '*': {
2854                                                 errorf(HERE, "%K does not name a type", &token);
2855
2856                                                 entity_t *const entity = create_error_entity(token.base.symbol, ENTITY_TYPEDEF);
2857
2858                                                 type = allocate_type_zero(TYPE_TYPEDEF);
2859                                                 type->typedeft.typedefe = &entity->typedefe;
2860
2861                                                 eat(T_IDENTIFIER);
2862                                                 saw_error = true;
2863                                                 continue;
2864                                         }
2865
2866                                         default:
2867                                                 goto finish_specifiers;
2868                                 }
2869                         }
2870
2871                         eat(T_IDENTIFIER);
2872                         type = typedef_type;
2873                         break;
2874                 }
2875
2876                 /* function specifier */
2877                 default:
2878                         goto finish_specifiers;
2879                 }
2880         }
2881
2882 finish_specifiers:
2883         specifiers->attributes = parse_attributes(specifiers->attributes);
2884
2885         if (type == NULL || (saw_error && type_specifiers != 0)) {
2886                 atomic_type_kind_t atomic_type;
2887
2888                 /* match valid basic types */
2889                 switch (type_specifiers) {
2890                 case SPECIFIER_VOID:
2891                         atomic_type = ATOMIC_TYPE_VOID;
2892                         break;
2893                 case SPECIFIER_WCHAR_T:
2894                         atomic_type = ATOMIC_TYPE_WCHAR_T;
2895                         break;
2896                 case SPECIFIER_CHAR:
2897                         atomic_type = ATOMIC_TYPE_CHAR;
2898                         break;
2899                 case SPECIFIER_SIGNED | SPECIFIER_CHAR:
2900                         atomic_type = ATOMIC_TYPE_SCHAR;
2901                         break;
2902                 case SPECIFIER_UNSIGNED | SPECIFIER_CHAR:
2903                         atomic_type = ATOMIC_TYPE_UCHAR;
2904                         break;
2905                 case SPECIFIER_SHORT:
2906                 case SPECIFIER_SIGNED | SPECIFIER_SHORT:
2907                 case SPECIFIER_SHORT | SPECIFIER_INT:
2908                 case SPECIFIER_SIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2909                         atomic_type = ATOMIC_TYPE_SHORT;
2910                         break;
2911                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT:
2912                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2913                         atomic_type = ATOMIC_TYPE_USHORT;
2914                         break;
2915                 case SPECIFIER_INT:
2916                 case SPECIFIER_SIGNED:
2917                 case SPECIFIER_SIGNED | SPECIFIER_INT:
2918                         atomic_type = ATOMIC_TYPE_INT;
2919                         break;
2920                 case SPECIFIER_UNSIGNED:
2921                 case SPECIFIER_UNSIGNED | SPECIFIER_INT:
2922                         atomic_type = ATOMIC_TYPE_UINT;
2923                         break;
2924                 case SPECIFIER_LONG:
2925                 case SPECIFIER_SIGNED | SPECIFIER_LONG:
2926                 case SPECIFIER_LONG | SPECIFIER_INT:
2927                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2928                         atomic_type = ATOMIC_TYPE_LONG;
2929                         break;
2930                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:
2931                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2932                         atomic_type = ATOMIC_TYPE_ULONG;
2933                         break;
2934
2935                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2936                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2937                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG | SPECIFIER_INT:
2938                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2939                         | SPECIFIER_INT:
2940                         atomic_type = ATOMIC_TYPE_LONGLONG;
2941                         goto warn_about_long_long;
2942
2943                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2944                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2945                         | SPECIFIER_INT:
2946                         atomic_type = ATOMIC_TYPE_ULONGLONG;
2947 warn_about_long_long:
2948                         warningf(WARN_LONG_LONG, &specifiers->source_position, "ISO C90 does not support 'long long'");
2949                         break;
2950
2951                 case SPECIFIER_UNSIGNED | SPECIFIER_INT8:
2952                         atomic_type = unsigned_int8_type_kind;
2953                         break;
2954
2955                 case SPECIFIER_UNSIGNED | SPECIFIER_INT16:
2956                         atomic_type = unsigned_int16_type_kind;
2957                         break;
2958
2959                 case SPECIFIER_UNSIGNED | SPECIFIER_INT32:
2960                         atomic_type = unsigned_int32_type_kind;
2961                         break;
2962
2963                 case SPECIFIER_UNSIGNED | SPECIFIER_INT64:
2964                         atomic_type = unsigned_int64_type_kind;
2965                         break;
2966
2967                 case SPECIFIER_UNSIGNED | SPECIFIER_INT128:
2968                         atomic_type = unsigned_int128_type_kind;
2969                         break;
2970
2971                 case SPECIFIER_INT8:
2972                 case SPECIFIER_SIGNED | SPECIFIER_INT8:
2973                         atomic_type = int8_type_kind;
2974                         break;
2975
2976                 case SPECIFIER_INT16:
2977                 case SPECIFIER_SIGNED | SPECIFIER_INT16:
2978                         atomic_type = int16_type_kind;
2979                         break;
2980
2981                 case SPECIFIER_INT32:
2982                 case SPECIFIER_SIGNED | SPECIFIER_INT32:
2983                         atomic_type = int32_type_kind;
2984                         break;
2985
2986                 case SPECIFIER_INT64:
2987                 case SPECIFIER_SIGNED | SPECIFIER_INT64:
2988                         atomic_type = int64_type_kind;
2989                         break;
2990
2991                 case SPECIFIER_INT128:
2992                 case SPECIFIER_SIGNED | SPECIFIER_INT128:
2993                         atomic_type = int128_type_kind;
2994                         break;
2995
2996                 case SPECIFIER_FLOAT:
2997                         atomic_type = ATOMIC_TYPE_FLOAT;
2998                         break;
2999                 case SPECIFIER_DOUBLE:
3000                         atomic_type = ATOMIC_TYPE_DOUBLE;
3001                         break;
3002                 case SPECIFIER_LONG | SPECIFIER_DOUBLE:
3003                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
3004                         break;
3005                 case SPECIFIER_BOOL:
3006                         atomic_type = ATOMIC_TYPE_BOOL;
3007                         break;
3008                 case SPECIFIER_FLOAT | SPECIFIER_COMPLEX:
3009                 case SPECIFIER_FLOAT | SPECIFIER_IMAGINARY:
3010                         atomic_type = ATOMIC_TYPE_FLOAT;
3011                         break;
3012                 case SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
3013                 case SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
3014                         atomic_type = ATOMIC_TYPE_DOUBLE;
3015                         break;
3016                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
3017                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
3018                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
3019                         break;
3020                 default: {
3021                         /* invalid specifier combination, give an error message */
3022                         source_position_t const* const pos = &specifiers->source_position;
3023                         if (type_specifiers == 0) {
3024                                 if (!saw_error) {
3025                                         /* ISO/IEC 14882:1998(E) §C.1.5:4 */
3026                                         if (!(c_mode & _CXX) && !strict_mode) {
3027                                                 warningf(WARN_IMPLICIT_INT, pos, "no type specifiers in declaration, using 'int'");
3028                                                 atomic_type = ATOMIC_TYPE_INT;
3029                                                 break;
3030                                         } else {
3031                                                 errorf(pos, "no type specifiers given in declaration");
3032                                         }
3033                                 }
3034                         } else if ((type_specifiers & SPECIFIER_SIGNED) &&
3035                                   (type_specifiers & SPECIFIER_UNSIGNED)) {
3036                                 errorf(pos, "signed and unsigned specifiers given");
3037                         } else if (type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
3038                                 errorf(pos, "only integer types can be signed or unsigned");
3039                         } else {
3040                                 errorf(pos, "multiple datatypes in declaration");
3041                         }
3042                         goto end_error;
3043                 }
3044                 }
3045
3046                 if (type_specifiers & SPECIFIER_COMPLEX) {
3047                         type = allocate_type_zero(TYPE_COMPLEX);
3048                 } else if (type_specifiers & SPECIFIER_IMAGINARY) {
3049                         type = allocate_type_zero(TYPE_IMAGINARY);
3050                 } else {
3051                         type = allocate_type_zero(TYPE_ATOMIC);
3052                 }
3053                 type->atomic.akind = atomic_type;
3054                 newtype = true;
3055         } else if (type_specifiers != 0) {
3056                 errorf(&specifiers->source_position, "multiple datatypes in declaration");
3057         }
3058
3059         /* FIXME: check type qualifiers here */
3060         type->base.qualifiers = qualifiers;
3061
3062         if (newtype) {
3063                 type = identify_new_type(type);
3064         } else {
3065                 type = typehash_insert(type);
3066         }
3067
3068         if (specifiers->attributes != NULL)
3069                 type = handle_type_attributes(specifiers->attributes, type);
3070         specifiers->type = type;
3071         return;
3072
3073 end_error:
3074         specifiers->type = type_error_type;
3075 }
3076
3077 static type_qualifiers_t parse_type_qualifiers(void)
3078 {
3079         type_qualifiers_t qualifiers = TYPE_QUALIFIER_NONE;
3080
3081         while (true) {
3082                 switch (token.kind) {
3083                 /* type qualifiers */
3084                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
3085                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
3086                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
3087                 /* microsoft extended type modifiers */
3088                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
3089                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
3090                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
3091                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
3092                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
3093
3094                 default:
3095                         return qualifiers;
3096                 }
3097         }
3098 }
3099
3100 /**
3101  * Parses an K&R identifier list
3102  */
3103 static void parse_identifier_list(scope_t *scope)
3104 {
3105         assert(token.kind == T_IDENTIFIER);
3106         do {
3107                 entity_t *const entity = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, token.base.symbol, HERE);
3108                 /* a K&R parameter has no type, yet */
3109                 eat(T_IDENTIFIER);
3110
3111                 if (scope != NULL)
3112                         append_entity(scope, entity);
3113         } while (next_if(',') && token.kind == T_IDENTIFIER);
3114 }
3115
3116 static entity_t *parse_parameter(void)
3117 {
3118         declaration_specifiers_t specifiers;
3119         parse_declaration_specifiers(&specifiers);
3120
3121         entity_t *entity = parse_declarator(&specifiers,
3122                         DECL_MAY_BE_ABSTRACT | DECL_IS_PARAMETER);
3123         anonymous_entity = NULL;
3124         return entity;
3125 }
3126
3127 static void semantic_parameter_incomplete(const entity_t *entity)
3128 {
3129         assert(entity->kind == ENTITY_PARAMETER);
3130
3131         /* §6.7.5.3:4  After adjustment, the parameters in a parameter type
3132          *             list in a function declarator that is part of a
3133          *             definition of that function shall not have
3134          *             incomplete type. */
3135         type_t *type = skip_typeref(entity->declaration.type);
3136         if (is_type_incomplete(type)) {
3137                 errorf(&entity->base.source_position, "'%N' has incomplete type", entity);
3138         }
3139 }
3140
3141 static bool has_parameters(void)
3142 {
3143         /* func(void) is not a parameter */
3144         if (look_ahead(1)->kind != ')')
3145                 return true;
3146         if (token.kind == T_IDENTIFIER) {
3147                 entity_t const *const entity = get_entity(token.base.symbol, NAMESPACE_NORMAL);
3148                 if (entity == NULL)
3149                         return true;
3150                 if (entity->kind != ENTITY_TYPEDEF)
3151                         return true;
3152                 type_t const *const type = skip_typeref(entity->typedefe.type);
3153                 if (!is_type_void(type))
3154                         return true;
3155                 if (c_mode & _CXX) {
3156                         /* ISO/IEC 14882:1998(E) §8.3.5:2  It must be literally (void).  A typedef
3157                          * is not allowed. */
3158                         errorf(HERE, "empty parameter list defined with a typedef of 'void' not allowed in C++");
3159                 } else if (type->base.qualifiers != TYPE_QUALIFIER_NONE) {
3160                         /* §6.7.5.3:10  Qualification is not allowed here. */
3161                         errorf(HERE, "'void' as parameter must not have type qualifiers");
3162                 }
3163         } else if (token.kind != T_void) {
3164                 return true;
3165         }
3166         next_token();
3167         return false;
3168 }
3169
3170 /**
3171  * Parses function type parameters (and optionally creates variable_t entities
3172  * for them in a scope)
3173  */
3174 static void parse_parameters(function_type_t *type, scope_t *scope)
3175 {
3176         add_anchor_token(')');
3177         eat('(');
3178
3179         if (token.kind == T_IDENTIFIER            &&
3180             !is_typedef_symbol(token.base.symbol) &&
3181             (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
3182                 type->kr_style_parameters = true;
3183                 parse_identifier_list(scope);
3184         } else if (token.kind == ')') {
3185                 /* ISO/IEC 14882:1998(E) §C.1.6:1 */
3186                 if (!(c_mode & _CXX))
3187                         type->unspecified_parameters = true;
3188         } else if (has_parameters()) {
3189                 function_parameter_t **anchor = &type->parameters;
3190                 add_anchor_token(',');
3191                 do {
3192                         switch (token.kind) {
3193                         case T_DOTDOTDOT:
3194                                 eat(T_DOTDOTDOT);
3195                                 type->variadic = true;
3196                                 goto parameters_finished;
3197
3198                         case T_IDENTIFIER:
3199                         DECLARATION_START
3200                         {
3201                                 entity_t *entity = parse_parameter();
3202                                 if (entity->kind == ENTITY_TYPEDEF) {
3203                                         errorf(&entity->base.source_position,
3204                                                         "typedef not allowed as function parameter");
3205                                         break;
3206                                 }
3207                                 assert(is_declaration(entity));
3208
3209                                 semantic_parameter_incomplete(entity);
3210
3211                                 function_parameter_t *const parameter =
3212                                         allocate_parameter(entity->declaration.type);
3213
3214                                 if (scope != NULL) {
3215                                         append_entity(scope, entity);
3216                                 }
3217
3218                                 *anchor = parameter;
3219                                 anchor  = &parameter->next;
3220                                 break;
3221                         }
3222
3223                         default:
3224                                 goto parameters_finished;
3225                         }
3226                 } while (next_if(','));
3227 parameters_finished:
3228                 rem_anchor_token(',');
3229         }
3230
3231         rem_anchor_token(')');
3232         expect(')');
3233 }
3234
3235 typedef enum construct_type_kind_t {
3236         CONSTRUCT_POINTER = 1,
3237         CONSTRUCT_REFERENCE,
3238         CONSTRUCT_FUNCTION,
3239         CONSTRUCT_ARRAY
3240 } construct_type_kind_t;
3241
3242 typedef union construct_type_t construct_type_t;
3243
3244 typedef struct construct_type_base_t {
3245         construct_type_kind_t  kind;
3246         source_position_t      pos;
3247         construct_type_t      *next;
3248 } construct_type_base_t;
3249
3250 typedef struct parsed_pointer_t {
3251         construct_type_base_t  base;
3252         type_qualifiers_t      type_qualifiers;
3253         variable_t            *base_variable;  /**< MS __based extension. */
3254 } parsed_pointer_t;
3255
3256 typedef struct parsed_reference_t {
3257         construct_type_base_t base;
3258 } parsed_reference_t;
3259
3260 typedef struct construct_function_type_t {
3261         construct_type_base_t  base;
3262         type_t                *function_type;
3263 } construct_function_type_t;
3264
3265 typedef struct parsed_array_t {
3266         construct_type_base_t  base;
3267         type_qualifiers_t      type_qualifiers;
3268         bool                   is_static;
3269         bool                   is_variable;
3270         expression_t          *size;
3271 } parsed_array_t;
3272
3273 union construct_type_t {
3274         construct_type_kind_t     kind;
3275         construct_type_base_t     base;
3276         parsed_pointer_t          pointer;
3277         parsed_reference_t        reference;
3278         construct_function_type_t function;
3279         parsed_array_t            array;
3280 };
3281
3282 static construct_type_t *allocate_declarator_zero(construct_type_kind_t const kind, size_t const size)
3283 {
3284         construct_type_t *const cons = obstack_alloc(&temp_obst, size);
3285         memset(cons, 0, size);
3286         cons->kind     = kind;
3287         cons->base.pos = *HERE;
3288         return cons;
3289 }
3290
3291 /* §6.7.5.1 */
3292 static construct_type_t *parse_pointer_declarator(void)
3293 {
3294         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_POINTER, sizeof(parsed_pointer_t));
3295         eat('*');
3296         cons->pointer.type_qualifiers = parse_type_qualifiers();
3297         //cons->pointer.base_variable   = base_variable;
3298
3299         return cons;
3300 }
3301
3302 /* ISO/IEC 14882:1998(E) §8.3.2 */
3303 static construct_type_t *parse_reference_declarator(void)
3304 {
3305         if (!(c_mode & _CXX))
3306                 errorf(HERE, "references are only available for C++");
3307
3308         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_REFERENCE, sizeof(parsed_reference_t));
3309         eat('&');
3310
3311         return cons;
3312 }
3313
3314 /* §6.7.5.2 */
3315 static construct_type_t *parse_array_declarator(void)
3316 {
3317         construct_type_t *const cons  = allocate_declarator_zero(CONSTRUCT_ARRAY, sizeof(parsed_array_t));
3318         parsed_array_t   *const array = &cons->array;
3319
3320         eat('[');
3321         add_anchor_token(']');
3322
3323         bool is_static = next_if(T_static);
3324
3325         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
3326
3327         if (!is_static)
3328                 is_static = next_if(T_static);
3329
3330         array->type_qualifiers = type_qualifiers;
3331         array->is_static       = is_static;
3332
3333         expression_t *size = NULL;
3334         if (token.kind == '*' && look_ahead(1)->kind == ']') {
3335                 array->is_variable = true;
3336                 eat('*');
3337         } else if (token.kind != ']') {
3338                 size = parse_assignment_expression();
3339
3340                 /* §6.7.5.2:1  Array size must have integer type */
3341                 type_t *const orig_type = size->base.type;
3342                 type_t *const type      = skip_typeref(orig_type);
3343                 if (!is_type_integer(type) && is_type_valid(type)) {
3344                         errorf(&size->base.source_position,
3345                                "array size '%E' must have integer type but has type '%T'",
3346                                size, orig_type);
3347                 }
3348
3349                 array->size = size;
3350                 mark_vars_read(size, NULL);
3351         }
3352
3353         if (is_static && size == NULL)
3354                 errorf(&array->base.pos, "static array parameters require a size");
3355
3356         rem_anchor_token(']');
3357         expect(']');
3358         return cons;
3359 }
3360
3361 /* §6.7.5.3 */
3362 static construct_type_t *parse_function_declarator(scope_t *scope)
3363 {
3364         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_FUNCTION, sizeof(construct_function_type_t));
3365
3366         type_t          *type  = allocate_type_zero(TYPE_FUNCTION);
3367         function_type_t *ftype = &type->function;
3368
3369         ftype->linkage            = current_linkage;
3370         ftype->calling_convention = CC_DEFAULT;
3371
3372         parse_parameters(ftype, scope);
3373
3374         cons->function.function_type = type;
3375
3376         return cons;
3377 }
3378
3379 typedef struct parse_declarator_env_t {
3380         bool               may_be_abstract : 1;
3381         bool               must_be_abstract : 1;
3382         decl_modifiers_t   modifiers;
3383         symbol_t          *symbol;
3384         source_position_t  source_position;
3385         scope_t            parameters;
3386         attribute_t       *attributes;
3387 } parse_declarator_env_t;
3388
3389 /* §6.7.5 */
3390 static construct_type_t *parse_inner_declarator(parse_declarator_env_t *env)
3391 {
3392         /* construct a single linked list of construct_type_t's which describe
3393          * how to construct the final declarator type */
3394         construct_type_t  *first      = NULL;
3395         construct_type_t **anchor     = &first;
3396
3397         env->attributes = parse_attributes(env->attributes);
3398
3399         for (;;) {
3400                 construct_type_t *type;
3401                 //variable_t       *based = NULL; /* MS __based extension */
3402                 switch (token.kind) {
3403                         case '&':
3404                                 type = parse_reference_declarator();
3405                                 break;
3406
3407                         case T__based: {
3408                                 panic("based not supported anymore");
3409                                 /* FALLTHROUGH */
3410                         }
3411
3412                         case '*':
3413                                 type = parse_pointer_declarator();
3414                                 break;
3415
3416                         default:
3417                                 goto ptr_operator_end;
3418                 }
3419
3420                 *anchor = type;
3421                 anchor  = &type->base.next;
3422
3423                 /* TODO: find out if this is correct */
3424                 env->attributes = parse_attributes(env->attributes);
3425         }
3426
3427 ptr_operator_end: ;
3428         construct_type_t *inner_types = NULL;
3429
3430         switch (token.kind) {
3431         case T_IDENTIFIER:
3432                 if (env->must_be_abstract) {
3433                         errorf(HERE, "no identifier expected in typename");
3434                 } else {
3435                         env->symbol          = token.base.symbol;
3436                         env->source_position = *HERE;
3437                 }
3438                 eat(T_IDENTIFIER);
3439                 break;
3440
3441         case '(': {
3442                 /* Parenthesized declarator or function declarator? */
3443                 token_t const *const la1 = look_ahead(1);
3444                 switch (la1->kind) {
3445                         case T_IDENTIFIER:
3446                                 if (is_typedef_symbol(la1->base.symbol)) {
3447                         case ')':
3448                                         /* §6.7.6:2 footnote 126:  Empty parentheses in a type name are
3449                                          * interpreted as ``function with no parameter specification'', rather
3450                                          * than redundant parentheses around the omitted identifier. */
3451                         default:
3452                                         /* Function declarator. */
3453                                         if (!env->may_be_abstract) {
3454                                                 errorf(HERE, "function declarator must have a name");
3455                                         }
3456                                 } else {
3457                         case '&':
3458                         case '(':
3459                         case '*':
3460                         case '[':
3461                         case T___attribute__: /* FIXME __attribute__ might also introduce a parameter of a function declarator. */
3462                                         /* Paranthesized declarator. */
3463                                         eat('(');
3464                                         add_anchor_token(')');
3465                                         inner_types = parse_inner_declarator(env);
3466                                         if (inner_types != NULL) {
3467                                                 /* All later declarators only modify the return type */
3468                                                 env->must_be_abstract = true;
3469                                         }
3470                                         rem_anchor_token(')');
3471                                         expect(')');
3472                                 }
3473                                 break;
3474                 }
3475                 break;
3476         }
3477
3478         default:
3479                 if (env->may_be_abstract)
3480                         break;
3481                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', NULL);
3482                 eat_until_anchor();
3483                 return NULL;
3484         }
3485
3486         construct_type_t **const p = anchor;
3487
3488         for (;;) {
3489                 construct_type_t *type;
3490                 switch (token.kind) {
3491                 case '(': {
3492                         scope_t *scope = NULL;
3493                         if (!env->must_be_abstract) {
3494                                 scope = &env->parameters;
3495                         }
3496
3497                         type = parse_function_declarator(scope);
3498                         break;
3499                 }
3500                 case '[':
3501                         type = parse_array_declarator();
3502                         break;
3503                 default:
3504                         goto declarator_finished;
3505                 }
3506
3507                 /* insert in the middle of the list (at p) */
3508                 type->base.next = *p;
3509                 *p              = type;
3510                 if (anchor == p)
3511                         anchor = &type->base.next;
3512         }
3513
3514 declarator_finished:
3515         /* append inner_types at the end of the list, we don't to set anchor anymore
3516          * as it's not needed anymore */
3517         *anchor = inner_types;
3518
3519         return first;
3520 }
3521
3522 static type_t *construct_declarator_type(construct_type_t *construct_list,
3523                                          type_t *type)
3524 {
3525         construct_type_t *iter = construct_list;
3526         for (; iter != NULL; iter = iter->base.next) {
3527                 source_position_t const* const pos = &iter->base.pos;
3528                 switch (iter->kind) {
3529                 case CONSTRUCT_FUNCTION: {
3530                         construct_function_type_t *function      = &iter->function;
3531                         type_t                    *function_type = function->function_type;
3532
3533                         function_type->function.return_type = type;
3534
3535                         type_t *skipped_return_type = skip_typeref(type);
3536                         /* §6.7.5.3:1 */
3537                         if (is_type_function(skipped_return_type)) {
3538                                 errorf(pos, "function returning function is not allowed");
3539                         } else if (is_type_array(skipped_return_type)) {
3540                                 errorf(pos, "function returning array is not allowed");
3541                         } else {
3542                                 if (skipped_return_type->base.qualifiers != 0) {
3543                                         warningf(WARN_IGNORED_QUALIFIERS, pos, "type qualifiers in return type of function type are meaningless");
3544                                 }
3545                         }
3546
3547                         /* The function type was constructed earlier.  Freeing it here will
3548                          * destroy other types. */
3549                         type = typehash_insert(function_type);
3550                         continue;
3551                 }
3552
3553                 case CONSTRUCT_POINTER: {
3554                         if (is_type_reference(skip_typeref(type)))
3555                                 errorf(pos, "cannot declare a pointer to reference");
3556
3557                         parsed_pointer_t *pointer = &iter->pointer;
3558                         type = make_based_pointer_type(type, pointer->type_qualifiers, pointer->base_variable);
3559                         continue;
3560                 }
3561
3562                 case CONSTRUCT_REFERENCE:
3563                         if (is_type_reference(skip_typeref(type)))
3564                                 errorf(pos, "cannot declare a reference to reference");
3565
3566                         type = make_reference_type(type);
3567                         continue;
3568
3569                 case CONSTRUCT_ARRAY: {
3570                         if (is_type_reference(skip_typeref(type)))
3571                                 errorf(pos, "cannot declare an array of references");
3572
3573                         parsed_array_t *array      = &iter->array;
3574                         type_t         *array_type = allocate_type_zero(TYPE_ARRAY);
3575
3576                         expression_t *size_expression = array->size;
3577                         if (size_expression != NULL) {
3578                                 size_expression
3579                                         = create_implicit_cast(size_expression, type_size_t);
3580                         }
3581
3582                         array_type->base.qualifiers       = array->type_qualifiers;
3583                         array_type->array.element_type    = type;
3584                         array_type->array.is_static       = array->is_static;
3585                         array_type->array.is_variable     = array->is_variable;
3586                         array_type->array.size_expression = size_expression;
3587
3588                         if (size_expression != NULL) {
3589                                 switch (is_constant_expression(size_expression)) {
3590                                 case EXPR_CLASS_CONSTANT: {
3591                                         long const size = fold_constant_to_int(size_expression);
3592                                         array_type->array.size          = size;
3593                                         array_type->array.size_constant = true;
3594                                         /* §6.7.5.2:1  If the expression is a constant expression,
3595                                          * it shall have a value greater than zero. */
3596                                         if (size < 0) {
3597                                                 errorf(&size_expression->base.source_position,
3598                                                            "size of array must be greater than zero");
3599                                         } else if (size == 0 && !GNU_MODE) {
3600                                                 errorf(&size_expression->base.source_position,
3601                                                            "size of array must be greater than zero (zero length arrays are a GCC extension)");
3602                                         }
3603                                         break;
3604                                 }
3605
3606                                 case EXPR_CLASS_VARIABLE:
3607                                         array_type->array.is_vla = true;
3608                                         break;
3609
3610                                 case EXPR_CLASS_ERROR:
3611                                         break;
3612                                 }
3613                         }
3614
3615                         type_t *skipped_type = skip_typeref(type);
3616                         /* §6.7.5.2:1 */
3617                         if (is_type_incomplete(skipped_type)) {
3618                                 errorf(pos, "array of incomplete type '%T' is not allowed", type);
3619                         } else if (is_type_function(skipped_type)) {
3620                                 errorf(pos, "array of functions is not allowed");
3621                         }
3622                         type = identify_new_type(array_type);
3623                         continue;
3624                 }
3625                 }
3626                 internal_errorf(pos, "invalid type construction found");
3627         }
3628
3629         return type;
3630 }
3631
3632 static type_t *automatic_type_conversion(type_t *orig_type);
3633
3634 static type_t *semantic_parameter(const source_position_t *pos,
3635                                   type_t *type,
3636                                   const declaration_specifiers_t *specifiers,
3637                                   entity_t const *const param)
3638 {
3639         /* §6.7.5.3:7  A declaration of a parameter as ``array of type''
3640          *             shall be adjusted to ``qualified pointer to type'',
3641          *             [...]
3642          * §6.7.5.3:8  A declaration of a parameter as ``function returning
3643          *             type'' shall be adjusted to ``pointer to function
3644          *             returning type'', as in 6.3.2.1. */
3645         type = automatic_type_conversion(type);
3646
3647         if (specifiers->is_inline && is_type_valid(type)) {
3648                 errorf(pos, "'%N' declared 'inline'", param);
3649         }
3650
3651         /* §6.9.1:6  The declarations in the declaration list shall contain
3652          *           no storage-class specifier other than register and no
3653          *           initializations. */
3654         if (specifiers->thread_local || (
3655                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3656                         specifiers->storage_class != STORAGE_CLASS_REGISTER)
3657            ) {
3658                 errorf(pos, "invalid storage class for '%N'", param);
3659         }
3660
3661         /* delay test for incomplete type, because we might have (void)
3662          * which is legal but incomplete... */
3663
3664         return type;
3665 }
3666
3667 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
3668                                   declarator_flags_t flags)
3669 {
3670         parse_declarator_env_t env;
3671         memset(&env, 0, sizeof(env));
3672         env.may_be_abstract = (flags & DECL_MAY_BE_ABSTRACT) != 0;
3673
3674         construct_type_t *construct_type = parse_inner_declarator(&env);
3675         type_t           *orig_type      =
3676                 construct_declarator_type(construct_type, specifiers->type);
3677         type_t           *type           = skip_typeref(orig_type);
3678
3679         if (construct_type != NULL) {
3680                 obstack_free(&temp_obst, construct_type);
3681         }
3682
3683         attribute_t *attributes = parse_attributes(env.attributes);
3684         /* append (shared) specifier attribute behind attributes of this
3685          * declarator */
3686         attribute_t **anchor = &attributes;
3687         while (*anchor != NULL)
3688                 anchor = &(*anchor)->next;
3689         *anchor = specifiers->attributes;
3690
3691         entity_t *entity;
3692         if (specifiers->storage_class == STORAGE_CLASS_TYPEDEF) {
3693                 entity = allocate_entity_zero(ENTITY_TYPEDEF, NAMESPACE_NORMAL, env.symbol, &env.source_position);
3694                 entity->typedefe.type = orig_type;
3695
3696                 if (anonymous_entity != NULL) {
3697                         if (is_type_compound(type)) {
3698                                 assert(anonymous_entity->compound.alias == NULL);
3699                                 assert(anonymous_entity->kind == ENTITY_STRUCT ||
3700                                        anonymous_entity->kind == ENTITY_UNION);
3701                                 anonymous_entity->compound.alias = entity;
3702                                 anonymous_entity = NULL;
3703                         } else if (is_type_enum(type)) {
3704                                 assert(anonymous_entity->enume.alias == NULL);
3705                                 assert(anonymous_entity->kind == ENTITY_ENUM);
3706                                 anonymous_entity->enume.alias = entity;
3707                                 anonymous_entity = NULL;
3708                         }
3709                 }
3710         } else {
3711                 /* create a declaration type entity */
3712                 source_position_t const *const pos = env.symbol ? &env.source_position : &specifiers->source_position;
3713                 if (flags & DECL_CREATE_COMPOUND_MEMBER) {
3714                         entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, env.symbol, pos);
3715
3716                         if (env.symbol != NULL) {
3717                                 if (specifiers->is_inline && is_type_valid(type)) {
3718                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3719                                 }
3720
3721                                 if (specifiers->thread_local ||
3722                                                 specifiers->storage_class != STORAGE_CLASS_NONE) {
3723                                         errorf(&env.source_position, "'%N' must have no storage class", entity);
3724                                 }
3725                         }
3726                 } else if (flags & DECL_IS_PARAMETER) {
3727                         entity    = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, env.symbol, pos);
3728                         orig_type = semantic_parameter(&env.source_position, orig_type, specifiers, entity);
3729                 } else if (is_type_function(type)) {
3730                         entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, env.symbol, pos);
3731                         entity->function.is_inline      = specifiers->is_inline;
3732                         entity->function.elf_visibility = default_visibility;
3733                         entity->function.parameters     = env.parameters;
3734
3735                         if (env.symbol != NULL) {
3736                                 /* this needs fixes for C++ */
3737                                 bool in_function_scope = current_function != NULL;
3738
3739                                 if (specifiers->thread_local || (
3740                                                         specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3741                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3742                                                         (in_function_scope || specifiers->storage_class != STORAGE_CLASS_STATIC)
3743                                                 )) {
3744                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3745                                 }
3746                         }
3747                 } else {
3748                         entity = allocate_entity_zero(ENTITY_VARIABLE, NAMESPACE_NORMAL, env.symbol, pos);
3749                         entity->variable.elf_visibility = default_visibility;
3750                         entity->variable.thread_local   = specifiers->thread_local;
3751
3752                         if (env.symbol != NULL) {
3753                                 if (specifiers->is_inline && is_type_valid(type)) {
3754                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3755                                 }
3756
3757                                 bool invalid_storage_class = false;
3758                                 if (current_scope == file_scope) {
3759                                         if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3760                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3761                                                         specifiers->storage_class != STORAGE_CLASS_STATIC) {
3762                                                 invalid_storage_class = true;
3763                                         }
3764                                 } else {
3765                                         if (specifiers->thread_local &&
3766                                                         specifiers->storage_class == STORAGE_CLASS_NONE) {
3767                                                 invalid_storage_class = true;
3768                                         }
3769                                 }
3770                                 if (invalid_storage_class) {
3771                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3772                                 }
3773                         }
3774                 }
3775
3776                 entity->declaration.type       = orig_type;
3777                 entity->declaration.alignment  = get_type_alignment(orig_type);
3778                 entity->declaration.modifiers  = env.modifiers;
3779                 entity->declaration.attributes = attributes;
3780
3781                 storage_class_t storage_class = specifiers->storage_class;
3782                 entity->declaration.declared_storage_class = storage_class;
3783
3784                 if (storage_class == STORAGE_CLASS_NONE && current_function != NULL)
3785                         storage_class = STORAGE_CLASS_AUTO;
3786                 entity->declaration.storage_class = storage_class;
3787         }
3788
3789         if (attributes != NULL) {
3790                 handle_entity_attributes(attributes, entity);
3791         }
3792
3793         if (entity->kind == ENTITY_FUNCTION && !freestanding) {
3794                 adapt_special_functions(&entity->function);
3795         }
3796
3797         return entity;
3798 }
3799
3800 static type_t *parse_abstract_declarator(type_t *base_type)
3801 {
3802         parse_declarator_env_t env;
3803         memset(&env, 0, sizeof(env));
3804         env.may_be_abstract = true;
3805         env.must_be_abstract = true;
3806
3807         construct_type_t *construct_type = parse_inner_declarator(&env);
3808
3809         type_t *result = construct_declarator_type(construct_type, base_type);
3810         if (construct_type != NULL) {
3811                 obstack_free(&temp_obst, construct_type);
3812         }
3813         result = handle_type_attributes(env.attributes, result);
3814
3815         return result;
3816 }
3817
3818 /**
3819  * Check if the declaration of main is suspicious.  main should be a
3820  * function with external linkage, returning int, taking either zero
3821  * arguments, two, or three arguments of appropriate types, ie.
3822  *
3823  * int main([ int argc, char **argv [, char **env ] ]).
3824  *
3825  * @param decl    the declaration to check
3826  * @param type    the function type of the declaration
3827  */
3828 static void check_main(const entity_t *entity)
3829 {
3830         const source_position_t *pos = &entity->base.source_position;
3831         if (entity->kind != ENTITY_FUNCTION) {
3832                 warningf(WARN_MAIN, pos, "'main' is not a function");
3833                 return;
3834         }
3835
3836         if (entity->declaration.storage_class == STORAGE_CLASS_STATIC) {
3837                 warningf(WARN_MAIN, pos, "'main' is normally a non-static function");
3838         }
3839
3840         type_t *type = skip_typeref(entity->declaration.type);
3841         assert(is_type_function(type));
3842
3843         function_type_t const *const func_type = &type->function;
3844         type_t                *const ret_type  = func_type->return_type;
3845         if (!types_compatible(skip_typeref(ret_type), type_int)) {
3846                 warningf(WARN_MAIN, pos, "return type of 'main' should be 'int', but is '%T'", ret_type);
3847         }
3848         const function_parameter_t *parm = func_type->parameters;
3849         if (parm != NULL) {
3850                 type_t *const first_type        = skip_typeref(parm->type);
3851                 type_t *const first_type_unqual = get_unqualified_type(first_type);
3852                 if (!types_compatible(first_type_unqual, type_int)) {
3853                         warningf(WARN_MAIN, pos, "first argument of 'main' should be 'int', but is '%T'", parm->type);
3854                 }
3855                 parm = parm->next;
3856                 if (parm != NULL) {
3857                         type_t *const second_type = skip_typeref(parm->type);
3858                         type_t *const second_type_unqual
3859                                 = get_unqualified_type(second_type);
3860                         if (!types_compatible(second_type_unqual, type_char_ptr_ptr)) {
3861                                 warningf(WARN_MAIN, pos, "second argument of 'main' should be 'char**', but is '%T'", parm->type);
3862                         }
3863                         parm = parm->next;
3864                         if (parm != NULL) {
3865                                 type_t *const third_type = skip_typeref(parm->type);
3866                                 type_t *const third_type_unqual
3867                                         = get_unqualified_type(third_type);
3868                                 if (!types_compatible(third_type_unqual, type_char_ptr_ptr)) {
3869                                         warningf(WARN_MAIN, pos, "third argument of 'main' should be 'char**', but is '%T'", parm->type);
3870                                 }
3871                                 parm = parm->next;
3872                                 if (parm != NULL)
3873                                         goto warn_arg_count;
3874                         }
3875                 } else {
3876 warn_arg_count:
3877                         warningf(WARN_MAIN, pos, "'main' takes only zero, two or three arguments");
3878                 }
3879         }
3880 }
3881
3882 static void error_redefined_as_different_kind(const source_position_t *pos,
3883                 const entity_t *old, entity_kind_t new_kind)
3884 {
3885         char              const *const what = get_entity_kind_name(new_kind);
3886         source_position_t const *const ppos = &old->base.source_position;
3887         errorf(pos, "redeclaration of '%N' as %s (declared %P)", old, what, ppos);
3888 }
3889
3890 static bool is_entity_valid(entity_t *const ent)
3891 {
3892         if (is_declaration(ent)) {
3893                 return is_type_valid(skip_typeref(ent->declaration.type));
3894         } else if (ent->kind == ENTITY_TYPEDEF) {
3895                 return is_type_valid(skip_typeref(ent->typedefe.type));
3896         }
3897         return true;
3898 }
3899
3900 static bool contains_attribute(const attribute_t *list, const attribute_t *attr)
3901 {
3902         for (const attribute_t *tattr = list; tattr != NULL; tattr = tattr->next) {
3903                 if (attributes_equal(tattr, attr))
3904                         return true;
3905         }
3906         return false;
3907 }
3908
3909 /**
3910  * test wether new_list contains any attributes not included in old_list
3911  */
3912 static bool has_new_attributes(const attribute_t *old_list,
3913                                const attribute_t *new_list)
3914 {
3915         for (const attribute_t *attr = new_list; attr != NULL; attr = attr->next) {
3916                 if (!contains_attribute(old_list, attr))
3917                         return true;
3918         }
3919         return false;
3920 }
3921
3922 /**
3923  * Merge in attributes from an attribute list (probably from a previous
3924  * declaration with the same name). Warning: destroys the old structure
3925  * of the attribute list - don't reuse attributes after this call.
3926  */
3927 static void merge_in_attributes(declaration_t *decl, attribute_t *attributes)
3928 {
3929         attribute_t *next;
3930         for (attribute_t *attr = attributes; attr != NULL; attr = next) {
3931                 next = attr->next;
3932                 if (contains_attribute(decl->attributes, attr))
3933                         continue;
3934
3935                 /* move attribute to new declarations attributes list */
3936                 attr->next       = decl->attributes;
3937                 decl->attributes = attr;
3938         }
3939 }
3940
3941 static bool is_main(entity_t*);
3942
3943 /**
3944  * record entities for the NAMESPACE_NORMAL, and produce error messages/warnings
3945  * for various problems that occur for multiple definitions
3946  */
3947 entity_t *record_entity(entity_t *entity, const bool is_definition)
3948 {
3949         const symbol_t *const    symbol  = entity->base.symbol;
3950         const namespace_tag_t    namespc = (namespace_tag_t)entity->base.namespc;
3951         const source_position_t *pos     = &entity->base.source_position;
3952
3953         /* can happen in error cases */
3954         if (symbol == NULL)
3955                 return entity;
3956
3957         assert(!entity->base.parent_scope);
3958         assert(current_scope);
3959         entity->base.parent_scope = current_scope;
3960
3961         entity_t *const previous_entity = get_entity(symbol, namespc);
3962         /* pushing the same entity twice will break the stack structure */
3963         assert(previous_entity != entity);
3964
3965         if (entity->kind == ENTITY_FUNCTION) {
3966                 type_t *const orig_type = entity->declaration.type;
3967                 type_t *const type      = skip_typeref(orig_type);
3968
3969                 assert(is_type_function(type));
3970                 if (type->function.unspecified_parameters &&
3971                     previous_entity == NULL               &&
3972                     !entity->declaration.implicit) {
3973                         warningf(WARN_STRICT_PROTOTYPES, pos, "function declaration '%#N' is not a prototype", entity);
3974                 }
3975
3976                 if (is_main(entity)) {
3977                         check_main(entity);
3978                 }
3979         }
3980
3981         if (is_declaration(entity)                                    &&
3982             entity->declaration.storage_class == STORAGE_CLASS_EXTERN &&
3983             current_scope != file_scope                               &&
3984             !entity->declaration.implicit) {
3985                 warningf(WARN_NESTED_EXTERNS, pos, "nested extern declaration of '%#N'", entity);
3986         }
3987
3988         if (previous_entity != NULL) {
3989                 source_position_t const *const ppos = &previous_entity->base.source_position;
3990
3991                 if (previous_entity->base.parent_scope == &current_function->parameters &&
3992                                 previous_entity->base.parent_scope->depth + 1 == current_scope->depth) {
3993                         assert(previous_entity->kind == ENTITY_PARAMETER);
3994                         errorf(pos, "declaration of '%N' redeclares the '%N' (declared %P)", entity, previous_entity, ppos);
3995                         goto finish;
3996                 }
3997
3998                 if (previous_entity->base.parent_scope == current_scope) {
3999                         if (previous_entity->kind != entity->kind) {
4000                                 if (is_entity_valid(previous_entity) && is_entity_valid(entity)) {
4001                                         error_redefined_as_different_kind(pos, previous_entity,
4002                                                         entity->kind);
4003                                 }
4004                                 goto finish;
4005                         }
4006                         if (previous_entity->kind == ENTITY_ENUM_VALUE) {
4007                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4008                                 goto finish;
4009                         }
4010                         if (previous_entity->kind == ENTITY_TYPEDEF) {
4011                                 type_t *const type      = skip_typeref(entity->typedefe.type);
4012                                 type_t *const prev_type
4013                                         = skip_typeref(previous_entity->typedefe.type);
4014                                 if (c_mode & _CXX) {
4015                                         /* C++ allows double typedef if they are identical
4016                                          * (after skipping typedefs) */
4017                                         if (type == prev_type)
4018                                                 goto finish;
4019                                 } else {
4020                                         /* GCC extension: redef in system headers is allowed */
4021                                         if ((pos->is_system_header || ppos->is_system_header) &&
4022                                             types_compatible(type, prev_type))
4023                                                 goto finish;
4024                                 }
4025                                 errorf(pos, "redefinition of '%N' (declared %P)",
4026                                        entity, ppos);
4027                                 goto finish;
4028                         }
4029
4030                         /* at this point we should have only VARIABLES or FUNCTIONS */
4031                         assert(is_declaration(previous_entity) && is_declaration(entity));
4032
4033                         declaration_t *const prev_decl = &previous_entity->declaration;
4034                         declaration_t *const decl      = &entity->declaration;
4035
4036                         /* can happen for K&R style declarations */
4037                         if (prev_decl->type       == NULL             &&
4038                                         previous_entity->kind == ENTITY_PARAMETER &&
4039                                         entity->kind          == ENTITY_PARAMETER) {
4040                                 prev_decl->type                   = decl->type;
4041                                 prev_decl->storage_class          = decl->storage_class;
4042                                 prev_decl->declared_storage_class = decl->declared_storage_class;
4043                                 prev_decl->modifiers              = decl->modifiers;
4044                                 return previous_entity;
4045                         }
4046
4047                         type_t *const type      = skip_typeref(decl->type);
4048                         type_t *const prev_type = skip_typeref(prev_decl->type);
4049
4050                         if (!types_compatible(type, prev_type)) {
4051                                 errorf(pos, "declaration '%#N' is incompatible with '%#N' (declared %P)", entity, previous_entity, ppos);
4052                         } else {
4053                                 unsigned old_storage_class = prev_decl->storage_class;
4054
4055                                 if (is_definition                     &&
4056                                                 !prev_decl->used                  &&
4057                                                 !(prev_decl->modifiers & DM_USED) &&
4058                                                 prev_decl->storage_class == STORAGE_CLASS_STATIC) {
4059                                         warningf(WARN_REDUNDANT_DECLS, ppos, "unnecessary static forward declaration for '%#N'", previous_entity);
4060                                 }
4061
4062                                 storage_class_t new_storage_class = decl->storage_class;
4063
4064                                 /* pretend no storage class means extern for function
4065                                  * declarations (except if the previous declaration is neither
4066                                  * none nor extern) */
4067                                 if (entity->kind == ENTITY_FUNCTION) {
4068                                         /* the previous declaration could have unspecified parameters or
4069                                          * be a typedef, so use the new type */
4070                                         if (prev_type->function.unspecified_parameters || is_definition)
4071                                                 prev_decl->type = type;
4072
4073                                         switch (old_storage_class) {
4074                                                 case STORAGE_CLASS_NONE:
4075                                                         old_storage_class = STORAGE_CLASS_EXTERN;
4076                                                         /* FALLTHROUGH */
4077
4078                                                 case STORAGE_CLASS_EXTERN:
4079                                                         if (is_definition) {
4080                                                                 if (prev_type->function.unspecified_parameters && !is_main(entity)) {
4081                                                                         warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4082                                                                 }
4083                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
4084                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
4085                                                         }
4086                                                         break;
4087
4088                                                 default:
4089                                                         break;
4090                                         }
4091                                 } else if (is_type_incomplete(prev_type)) {
4092                                         prev_decl->type = type;
4093                                 }
4094
4095                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
4096                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
4097
4098 warn_redundant_declaration: ;
4099                                         bool has_new_attrs
4100                                                 = has_new_attributes(prev_decl->attributes,
4101                                                                      decl->attributes);
4102                                         if (has_new_attrs) {
4103                                                 merge_in_attributes(decl, prev_decl->attributes);
4104                                         } else if (!is_definition        &&
4105                                                         is_type_valid(prev_type) &&
4106                                                         !pos->is_system_header) {
4107                                                 warningf(WARN_REDUNDANT_DECLS, pos, "redundant declaration for '%N' (declared %P)", entity, ppos);
4108                                         }
4109                                 } else if (current_function == NULL) {
4110                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
4111                                                         new_storage_class == STORAGE_CLASS_STATIC) {
4112                                                 errorf(pos, "static declaration of '%N' follows non-static declaration (declared %P)", entity, ppos);
4113                                         } else if (old_storage_class == STORAGE_CLASS_EXTERN) {
4114                                                 prev_decl->storage_class          = STORAGE_CLASS_NONE;
4115                                                 prev_decl->declared_storage_class = STORAGE_CLASS_NONE;
4116                                         } else {
4117                                                 /* ISO/IEC 14882:1998(E) §C.1.2:1 */
4118                                                 if (c_mode & _CXX)
4119                                                         goto error_redeclaration;
4120                                                 goto warn_redundant_declaration;
4121                                         }
4122                                 } else if (is_type_valid(prev_type)) {
4123                                         if (old_storage_class == new_storage_class) {
4124 error_redeclaration:
4125                                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4126                                         } else {
4127                                                 errorf(pos, "redeclaration of '%N' with different linkage (declared %P)", entity, ppos);
4128                                         }
4129                                 }
4130                         }
4131
4132                         prev_decl->modifiers |= decl->modifiers;
4133                         if (entity->kind == ENTITY_FUNCTION) {
4134                                 previous_entity->function.is_inline |= entity->function.is_inline;
4135                         }
4136                         return previous_entity;
4137                 }
4138
4139                 warning_t why;
4140                 if (is_warn_on(why = WARN_SHADOW) ||
4141                     (is_warn_on(why = WARN_SHADOW_LOCAL) && previous_entity->base.parent_scope != file_scope)) {
4142                         char const *const what = get_entity_kind_name(previous_entity->kind);
4143                         warningf(why, pos, "'%N' shadows %s (declared %P)", entity, what, ppos);
4144                 }
4145         }
4146
4147         if (entity->kind == ENTITY_FUNCTION) {
4148                 if (is_definition &&
4149                                 entity->declaration.storage_class != STORAGE_CLASS_STATIC &&
4150                                 !is_main(entity)) {
4151                         if (is_warn_on(WARN_MISSING_PROTOTYPES)) {
4152                                 warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4153                         } else {
4154                                 goto warn_missing_declaration;
4155                         }
4156                 }
4157         } else if (entity->kind == ENTITY_VARIABLE) {
4158                 if (current_scope                     == file_scope &&
4159                                 entity->declaration.storage_class == STORAGE_CLASS_NONE &&
4160                                 !entity->declaration.implicit) {
4161 warn_missing_declaration:
4162                         warningf(WARN_MISSING_DECLARATIONS, pos, "no previous declaration for '%#N'", entity);
4163                 }
4164         }
4165
4166 finish:
4167         environment_push(entity);
4168         append_entity(current_scope, entity);
4169
4170         return entity;
4171 }
4172
4173 static void parser_error_multiple_definition(entity_t *entity,
4174                 const source_position_t *source_position)
4175 {
4176         errorf(source_position, "redefinition of '%N' (declared %P)", entity, &entity->base.source_position);
4177 }
4178
4179 static bool is_declaration_specifier(const token_t *token)
4180 {
4181         switch (token->kind) {
4182                 DECLARATION_START
4183                         return true;
4184                 case T_IDENTIFIER:
4185                         return is_typedef_symbol(token->base.symbol);
4186
4187                 default:
4188                         return false;
4189         }
4190 }
4191
4192 static void parse_init_declarator_rest(entity_t *entity)
4193 {
4194         type_t *orig_type = type_error_type;
4195
4196         if (entity->base.kind == ENTITY_TYPEDEF) {
4197                 source_position_t const *const pos = &entity->base.source_position;
4198                 errorf(pos, "'%N' is initialized (use __typeof__ instead)", entity);
4199         } else {
4200                 assert(is_declaration(entity));
4201                 orig_type = entity->declaration.type;
4202         }
4203
4204         type_t *type = skip_typeref(orig_type);
4205
4206         if (entity->kind == ENTITY_VARIABLE
4207                         && entity->variable.initializer != NULL) {
4208                 parser_error_multiple_definition(entity, HERE);
4209         }
4210         eat('=');
4211
4212         declaration_t *const declaration = &entity->declaration;
4213         bool must_be_constant = false;
4214         if (declaration->storage_class == STORAGE_CLASS_STATIC ||
4215             entity->base.parent_scope  == file_scope) {
4216                 must_be_constant = true;
4217         }
4218
4219         if (is_type_function(type)) {
4220                 source_position_t const *const pos = &entity->base.source_position;
4221                 errorf(pos, "'%N' is initialized like a variable", entity);
4222                 orig_type = type_error_type;
4223         }
4224
4225         parse_initializer_env_t env;
4226         env.type             = orig_type;
4227         env.must_be_constant = must_be_constant;
4228         env.entity           = entity;
4229
4230         initializer_t *initializer = parse_initializer(&env);
4231
4232         if (entity->kind == ENTITY_VARIABLE) {
4233                 /* §6.7.5:22  array initializers for arrays with unknown size
4234                  * determine the array type size */
4235                 declaration->type            = env.type;
4236                 entity->variable.initializer = initializer;
4237         }
4238 }
4239
4240 /* parse rest of a declaration without any declarator */
4241 static void parse_anonymous_declaration_rest(
4242                 const declaration_specifiers_t *specifiers)
4243 {
4244         eat(';');
4245         anonymous_entity = NULL;
4246
4247         source_position_t const *const pos = &specifiers->source_position;
4248         if (specifiers->storage_class != STORAGE_CLASS_NONE ||
4249                         specifiers->thread_local) {
4250                 warningf(WARN_OTHER, pos, "useless storage class in empty declaration");
4251         }
4252
4253         type_t *type = specifiers->type;
4254         switch (type->kind) {
4255                 case TYPE_COMPOUND_STRUCT:
4256                 case TYPE_COMPOUND_UNION: {
4257                         if (type->compound.compound->base.symbol == NULL) {
4258                                 warningf(WARN_OTHER, pos, "unnamed struct/union that defines no instances");
4259                         }
4260                         break;
4261                 }
4262
4263                 case TYPE_ENUM:
4264                         break;
4265
4266                 default:
4267                         warningf(WARN_OTHER, pos, "empty declaration");
4268                         break;
4269         }
4270 }
4271
4272 static void check_variable_type_complete(entity_t *ent)
4273 {
4274         if (ent->kind != ENTITY_VARIABLE)
4275                 return;
4276
4277         /* §6.7:7  If an identifier for an object is declared with no linkage, the
4278          *         type for the object shall be complete [...] */
4279         declaration_t *decl = &ent->declaration;
4280         if (decl->storage_class == STORAGE_CLASS_EXTERN ||
4281                         decl->storage_class == STORAGE_CLASS_STATIC)
4282                 return;
4283
4284         type_t *const type = skip_typeref(decl->type);
4285         if (!is_type_incomplete(type))
4286                 return;
4287
4288         /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
4289          * are given length one. */
4290         if (is_type_array(type) && ent->base.parent_scope == file_scope) {
4291                 ARR_APP1(declaration_t*, incomplete_arrays, decl);
4292                 return;
4293         }
4294
4295         errorf(&ent->base.source_position, "variable '%#N' has incomplete type", ent);
4296 }
4297
4298
4299 static void parse_declaration_rest(entity_t *ndeclaration,
4300                 const declaration_specifiers_t *specifiers,
4301                 parsed_declaration_func         finished_declaration,
4302                 declarator_flags_t              flags)
4303 {
4304         add_anchor_token(';');
4305         add_anchor_token(',');
4306         while (true) {
4307                 entity_t *entity = finished_declaration(ndeclaration, token.kind == '=');
4308
4309                 if (token.kind == '=') {
4310                         parse_init_declarator_rest(entity);
4311                 } else if (entity->kind == ENTITY_VARIABLE) {
4312                         /* ISO/IEC 14882:1998(E) §8.5.3:3  The initializer can be omitted
4313                          * [...] where the extern specifier is explicitly used. */
4314                         declaration_t *decl = &entity->declaration;
4315                         if (decl->storage_class != STORAGE_CLASS_EXTERN &&
4316                             is_type_reference(skip_typeref(decl->type))) {
4317                                 source_position_t const *const pos = &entity->base.source_position;
4318                                 errorf(pos, "reference '%#N' must be initialized", entity);
4319                         }
4320                 }
4321
4322                 check_variable_type_complete(entity);
4323
4324                 if (!next_if(','))
4325                         break;
4326
4327                 add_anchor_token('=');
4328                 ndeclaration = parse_declarator(specifiers, flags);
4329                 rem_anchor_token('=');
4330         }
4331         rem_anchor_token(',');
4332         rem_anchor_token(';');
4333         expect(';');
4334
4335         anonymous_entity = NULL;
4336 }
4337
4338 static entity_t *finished_kr_declaration(entity_t *entity, bool is_definition)
4339 {
4340         symbol_t *symbol = entity->base.symbol;
4341         if (symbol == NULL)
4342                 return entity;
4343
4344         assert(entity->base.namespc == NAMESPACE_NORMAL);
4345         entity_t *previous_entity = get_entity(symbol, NAMESPACE_NORMAL);
4346         if (previous_entity == NULL
4347                         || previous_entity->base.parent_scope != current_scope) {
4348                 errorf(&entity->base.source_position, "expected declaration of a function parameter, found '%Y'",
4349                        symbol);
4350                 return entity;
4351         }
4352
4353         if (is_definition) {
4354                 errorf(HERE, "'%N' is initialised", entity);
4355         }
4356
4357         return record_entity(entity, false);
4358 }
4359
4360 static void parse_declaration(parsed_declaration_func finished_declaration,
4361                               declarator_flags_t      flags)
4362 {
4363         add_anchor_token(';');
4364         declaration_specifiers_t specifiers;
4365         parse_declaration_specifiers(&specifiers);
4366         rem_anchor_token(';');
4367
4368         if (token.kind == ';') {
4369                 parse_anonymous_declaration_rest(&specifiers);
4370         } else {
4371                 entity_t *entity = parse_declarator(&specifiers, flags);
4372                 parse_declaration_rest(entity, &specifiers, finished_declaration, flags);
4373         }
4374 }
4375
4376 /* §6.5.2.2:6 */
4377 static type_t *get_default_promoted_type(type_t *orig_type)
4378 {
4379         type_t *result = orig_type;
4380
4381         type_t *type = skip_typeref(orig_type);
4382         if (is_type_integer(type)) {
4383                 result = promote_integer(type);
4384         } else if (is_type_atomic(type, ATOMIC_TYPE_FLOAT)) {
4385                 result = type_double;
4386         }
4387
4388         return result;
4389 }
4390
4391 static void parse_kr_declaration_list(entity_t *entity)
4392 {
4393         if (entity->kind != ENTITY_FUNCTION)
4394                 return;
4395
4396         type_t *type = skip_typeref(entity->declaration.type);
4397         assert(is_type_function(type));
4398         if (!type->function.kr_style_parameters)
4399                 return;
4400
4401         add_anchor_token('{');
4402
4403         PUSH_SCOPE(&entity->function.parameters);
4404
4405         entity_t *parameter = entity->function.parameters.entities;
4406         for ( ; parameter != NULL; parameter = parameter->base.next) {
4407                 assert(parameter->base.parent_scope == NULL);
4408                 parameter->base.parent_scope = current_scope;
4409                 environment_push(parameter);
4410         }
4411
4412         /* parse declaration list */
4413         for (;;) {
4414                 switch (token.kind) {
4415                         DECLARATION_START
4416                         /* This covers symbols, which are no type, too, and results in
4417                          * better error messages.  The typical cases are misspelled type
4418                          * names and missing includes. */
4419                         case T_IDENTIFIER:
4420                                 parse_declaration(finished_kr_declaration, DECL_IS_PARAMETER);
4421                                 break;
4422                         default:
4423                                 goto decl_list_end;
4424                 }
4425         }
4426 decl_list_end:
4427
4428         POP_SCOPE();
4429
4430         /* update function type */
4431         type_t *new_type = duplicate_type(type);
4432
4433         function_parameter_t  *parameters = NULL;
4434         function_parameter_t **anchor     = &parameters;
4435
4436         /* did we have an earlier prototype? */
4437         entity_t *proto_type = get_entity(entity->base.symbol, NAMESPACE_NORMAL);
4438         if (proto_type != NULL && proto_type->kind != ENTITY_FUNCTION)
4439                 proto_type = NULL;
4440
4441         function_parameter_t *proto_parameter = NULL;
4442         if (proto_type != NULL) {
4443                 type_t *proto_type_type = proto_type->declaration.type;
4444                 proto_parameter         = proto_type_type->function.parameters;
4445                 /* If a K&R function definition has a variadic prototype earlier, then
4446                  * make the function definition variadic, too. This should conform to
4447                  * §6.7.5.3:15 and §6.9.1:8. */
4448                 new_type->function.variadic = proto_type_type->function.variadic;
4449         } else {
4450                 /* §6.9.1.7: A K&R style parameter list does NOT act as a function
4451                  * prototype */
4452                 new_type->function.unspecified_parameters = true;
4453         }
4454
4455         bool need_incompatible_warning = false;
4456         parameter = entity->function.parameters.entities;
4457         for (; parameter != NULL; parameter = parameter->base.next,
4458                         proto_parameter =
4459                                 proto_parameter == NULL ? NULL : proto_parameter->next) {
4460                 if (parameter->kind != ENTITY_PARAMETER)
4461                         continue;
4462
4463                 type_t *parameter_type = parameter->declaration.type;
4464                 if (parameter_type == NULL) {
4465                         source_position_t const* const pos = &parameter->base.source_position;
4466                         if (strict_mode) {
4467                                 errorf(pos, "no type specified for function '%N'", parameter);
4468                                 parameter_type = type_error_type;
4469                         } else {
4470                                 warningf(WARN_IMPLICIT_INT, pos, "no type specified for function parameter '%N', using 'int'", parameter);
4471                                 parameter_type = type_int;
4472                         }
4473                         parameter->declaration.type = parameter_type;
4474                 }
4475
4476                 semantic_parameter_incomplete(parameter);
4477
4478                 /* we need the default promoted types for the function type */
4479                 type_t *not_promoted = parameter_type;
4480                 parameter_type       = get_default_promoted_type(parameter_type);
4481
4482                 /* gcc special: if the type of the prototype matches the unpromoted
4483                  * type don't promote */
4484                 if (!strict_mode && proto_parameter != NULL) {
4485                         type_t *proto_p_type = skip_typeref(proto_parameter->type);
4486                         type_t *promo_skip   = skip_typeref(parameter_type);
4487                         type_t *param_skip   = skip_typeref(not_promoted);
4488                         if (!types_compatible(proto_p_type, promo_skip)
4489                                 && types_compatible(proto_p_type, param_skip)) {
4490                                 /* don't promote */
4491                                 need_incompatible_warning = true;
4492                                 parameter_type = not_promoted;
4493                         }
4494                 }
4495                 function_parameter_t *const function_parameter
4496                         = allocate_parameter(parameter_type);
4497
4498                 *anchor = function_parameter;
4499                 anchor  = &function_parameter->next;
4500         }
4501
4502         new_type->function.parameters = parameters;
4503         new_type = identify_new_type(new_type);
4504
4505         if (need_incompatible_warning) {
4506                 symbol_t          const *const sym  = entity->base.symbol;
4507                 source_position_t const *const pos  = &entity->base.source_position;
4508                 source_position_t const *const ppos = &proto_type->base.source_position;
4509                 warningf(WARN_OTHER, pos, "declaration '%#N' is incompatible with '%#T' (declared %P)", proto_type, new_type, sym, ppos);
4510         }
4511         entity->declaration.type = new_type;
4512
4513         rem_anchor_token('{');
4514 }
4515
4516 static bool first_err = true;
4517
4518 /**
4519  * When called with first_err set, prints the name of the current function,
4520  * else does noting.
4521  */
4522 static void print_in_function(void)
4523 {
4524         if (first_err) {
4525                 first_err = false;
4526                 char const *const file = current_function->base.base.source_position.input_name;
4527                 diagnosticf("%s: In '%N':\n", file, (entity_t const*)current_function);
4528         }
4529 }
4530
4531 /**
4532  * Check if all labels are defined in the current function.
4533  * Check if all labels are used in the current function.
4534  */
4535 static void check_labels(void)
4536 {
4537         for (const goto_statement_t *goto_statement = goto_first;
4538             goto_statement != NULL;
4539             goto_statement = goto_statement->next) {
4540                 label_t *label = goto_statement->label;
4541                 if (label->base.source_position.input_name == NULL) {
4542                         print_in_function();
4543                         source_position_t const *const pos = &goto_statement->base.source_position;
4544                         errorf(pos, "'%N' used but not defined", (entity_t const*)label);
4545                  }
4546         }
4547
4548         if (is_warn_on(WARN_UNUSED_LABEL)) {
4549                 for (const label_statement_t *label_statement = label_first;
4550                          label_statement != NULL;
4551                          label_statement = label_statement->next) {
4552                         label_t *label = label_statement->label;
4553
4554                         if (! label->used) {
4555                                 print_in_function();
4556                                 source_position_t const *const pos = &label_statement->base.source_position;
4557                                 warningf(WARN_UNUSED_LABEL, pos, "'%N' defined but not used", (entity_t const*)label);
4558                         }
4559                 }
4560         }
4561 }
4562
4563 static void warn_unused_entity(warning_t const why, entity_t *entity, entity_t *const last)
4564 {
4565         entity_t const *const end = last != NULL ? last->base.next : NULL;
4566         for (; entity != end; entity = entity->base.next) {
4567                 if (!is_declaration(entity))
4568                         continue;
4569
4570                 declaration_t *declaration = &entity->declaration;
4571                 if (declaration->implicit)
4572                         continue;
4573
4574                 if (!declaration->used) {
4575                         print_in_function();
4576                         warningf(why, &entity->base.source_position, "'%N' is unused", entity);
4577                 } else if (entity->kind == ENTITY_VARIABLE && !entity->variable.read) {
4578                         print_in_function();
4579                         warningf(why, &entity->base.source_position, "'%N' is never read", entity);
4580                 }
4581         }
4582 }
4583
4584 static void check_unused_variables(statement_t *const stmt, void *const env)
4585 {
4586         (void)env;
4587
4588         switch (stmt->kind) {
4589                 case STATEMENT_DECLARATION: {
4590                         declaration_statement_t const *const decls = &stmt->declaration;
4591                         warn_unused_entity(WARN_UNUSED_VARIABLE, decls->declarations_begin, decls->declarations_end);
4592                         return;
4593                 }
4594
4595                 case STATEMENT_FOR:
4596                         warn_unused_entity(WARN_UNUSED_VARIABLE, stmt->fors.scope.entities, NULL);
4597                         return;
4598
4599                 default:
4600                         return;
4601         }
4602 }
4603
4604 /**
4605  * Check declarations of current_function for unused entities.
4606  */
4607 static void check_declarations(void)
4608 {
4609         if (is_warn_on(WARN_UNUSED_PARAMETER)) {
4610                 const scope_t *scope = &current_function->parameters;
4611                 warn_unused_entity(WARN_UNUSED_PARAMETER, scope->entities, NULL);
4612         }
4613         if (is_warn_on(WARN_UNUSED_VARIABLE)) {
4614                 walk_statements(current_function->statement, check_unused_variables,
4615                                 NULL);
4616         }
4617 }
4618
4619 static int determine_truth(expression_t const* const cond)
4620 {
4621         return
4622                 is_constant_expression(cond) != EXPR_CLASS_CONSTANT ? 0 :
4623                 fold_constant_to_bool(cond)                         ? 1 :
4624                 -1;
4625 }
4626
4627 static void check_reachable(statement_t *);
4628 static bool reaches_end;
4629
4630 static bool expression_returns(expression_t const *const expr)
4631 {
4632         switch (expr->kind) {
4633                 case EXPR_CALL: {
4634                         expression_t const *const func = expr->call.function;
4635                         type_t       const *const type = skip_typeref(func->base.type);
4636                         if (type->kind == TYPE_POINTER) {
4637                                 type_t const *const points_to
4638                                         = skip_typeref(type->pointer.points_to);
4639                                 if (points_to->kind == TYPE_FUNCTION
4640                                     && points_to->function.modifiers & DM_NORETURN)
4641                                         return false;
4642                         }
4643
4644                         if (!expression_returns(func))
4645                                 return false;
4646
4647                         for (call_argument_t const* arg = expr->call.arguments; arg != NULL; arg = arg->next) {
4648                                 if (!expression_returns(arg->expression))
4649                                         return false;
4650                         }
4651
4652                         return true;
4653                 }
4654
4655                 case EXPR_REFERENCE:
4656                 case EXPR_ENUM_CONSTANT:
4657                 case EXPR_LITERAL_CASES:
4658                 case EXPR_STRING_LITERAL:
4659                 case EXPR_WIDE_STRING_LITERAL:
4660                 case EXPR_COMPOUND_LITERAL: // TODO descend into initialisers
4661                 case EXPR_LABEL_ADDRESS:
4662                 case EXPR_CLASSIFY_TYPE:
4663                 case EXPR_SIZEOF: // TODO handle obscure VLA case
4664                 case EXPR_ALIGNOF:
4665                 case EXPR_FUNCNAME:
4666                 case EXPR_BUILTIN_CONSTANT_P:
4667                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
4668                 case EXPR_OFFSETOF:
4669                 case EXPR_ERROR:
4670                         return true;
4671
4672                 case EXPR_STATEMENT: {
4673                         bool old_reaches_end = reaches_end;
4674                         reaches_end = false;
4675                         check_reachable(expr->statement.statement);
4676                         bool returns = reaches_end;
4677                         reaches_end = old_reaches_end;
4678                         return returns;
4679                 }
4680
4681                 case EXPR_CONDITIONAL:
4682                         // TODO handle constant expression
4683
4684                         if (!expression_returns(expr->conditional.condition))
4685                                 return false;
4686
4687                         if (expr->conditional.true_expression != NULL
4688                                         && expression_returns(expr->conditional.true_expression))
4689                                 return true;
4690
4691                         return expression_returns(expr->conditional.false_expression);
4692
4693                 case EXPR_SELECT:
4694                         return expression_returns(expr->select.compound);
4695
4696                 case EXPR_ARRAY_ACCESS:
4697                         return
4698                                 expression_returns(expr->array_access.array_ref) &&
4699                                 expression_returns(expr->array_access.index);
4700
4701                 case EXPR_VA_START:
4702                         return expression_returns(expr->va_starte.ap);
4703
4704                 case EXPR_VA_ARG:
4705                         return expression_returns(expr->va_arge.ap);
4706
4707                 case EXPR_VA_COPY:
4708                         return expression_returns(expr->va_copye.src);
4709
4710                 case EXPR_UNARY_CASES_MANDATORY:
4711                         return expression_returns(expr->unary.value);
4712
4713                 case EXPR_UNARY_THROW:
4714                         return false;
4715
4716                 case EXPR_BINARY_CASES:
4717                         // TODO handle constant lhs of && and ||
4718                         return
4719                                 expression_returns(expr->binary.left) &&
4720                                 expression_returns(expr->binary.right);
4721         }
4722
4723         panic("unhandled expression");
4724 }
4725
4726 static bool initializer_returns(initializer_t const *const init)
4727 {
4728         switch (init->kind) {
4729                 case INITIALIZER_VALUE:
4730                         return expression_returns(init->value.value);
4731
4732                 case INITIALIZER_LIST: {
4733                         initializer_t * const*       i       = init->list.initializers;
4734                         initializer_t * const* const end     = i + init->list.len;
4735                         bool                         returns = true;
4736                         for (; i != end; ++i) {
4737                                 if (!initializer_returns(*i))
4738                                         returns = false;
4739                         }
4740                         return returns;
4741                 }
4742
4743                 case INITIALIZER_STRING:
4744                 case INITIALIZER_WIDE_STRING:
4745                 case INITIALIZER_DESIGNATOR: // designators have no payload
4746                         return true;
4747         }
4748         panic("unhandled initializer");
4749 }
4750
4751 static bool noreturn_candidate;
4752
4753 static void check_reachable(statement_t *const stmt)
4754 {
4755         if (stmt->base.reachable)
4756                 return;
4757         if (stmt->kind != STATEMENT_DO_WHILE)
4758                 stmt->base.reachable = true;
4759
4760         statement_t *last = stmt;
4761         statement_t *next;
4762         switch (stmt->kind) {
4763                 case STATEMENT_ERROR:
4764                 case STATEMENT_EMPTY:
4765                 case STATEMENT_ASM:
4766                         next = stmt->base.next;
4767                         break;
4768
4769                 case STATEMENT_DECLARATION: {
4770                         declaration_statement_t const *const decl = &stmt->declaration;
4771                         entity_t                const *      ent  = decl->declarations_begin;
4772                         entity_t                const *const last_decl = decl->declarations_end;
4773                         if (ent != NULL) {
4774                                 for (;; ent = ent->base.next) {
4775                                         if (ent->kind                 == ENTITY_VARIABLE &&
4776                                             ent->variable.initializer != NULL            &&
4777                                             !initializer_returns(ent->variable.initializer)) {
4778                                                 return;
4779                                         }
4780                                         if (ent == last_decl)
4781                                                 break;
4782                                 }
4783                         }
4784                         next = stmt->base.next;
4785                         break;
4786                 }
4787
4788                 case STATEMENT_COMPOUND:
4789                         next = stmt->compound.statements;
4790                         if (next == NULL)
4791                                 next = stmt->base.next;
4792                         break;
4793
4794                 case STATEMENT_RETURN: {
4795                         expression_t const *const val = stmt->returns.value;
4796                         if (val == NULL || expression_returns(val))
4797                                 noreturn_candidate = false;
4798                         return;
4799                 }
4800
4801                 case STATEMENT_IF: {
4802                         if_statement_t const *const ifs  = &stmt->ifs;
4803                         expression_t   const *const cond = ifs->condition;
4804
4805                         if (!expression_returns(cond))
4806                                 return;
4807
4808                         int const val = determine_truth(cond);
4809
4810                         if (val >= 0)
4811                                 check_reachable(ifs->true_statement);
4812
4813                         if (val > 0)
4814                                 return;
4815
4816                         if (ifs->false_statement != NULL) {
4817                                 check_reachable(ifs->false_statement);
4818                                 return;
4819                         }
4820
4821                         next = stmt->base.next;
4822                         break;
4823                 }
4824
4825                 case STATEMENT_SWITCH: {
4826                         switch_statement_t const *const switchs = &stmt->switchs;
4827                         expression_t       const *const expr    = switchs->expression;
4828
4829                         if (!expression_returns(expr))
4830                                 return;
4831
4832                         if (is_constant_expression(expr) == EXPR_CLASS_CONSTANT) {
4833                                 long                    const val      = fold_constant_to_int(expr);
4834                                 case_label_statement_t *      defaults = NULL;
4835                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4836                                         if (i->expression == NULL) {
4837                                                 defaults = i;
4838                                                 continue;
4839                                         }
4840
4841                                         if (i->first_case <= val && val <= i->last_case) {
4842                                                 check_reachable((statement_t*)i);
4843                                                 return;
4844                                         }
4845                                 }
4846
4847                                 if (defaults != NULL) {
4848                                         check_reachable((statement_t*)defaults);
4849                                         return;
4850                                 }
4851                         } else {
4852                                 bool has_default = false;
4853                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4854                                         if (i->expression == NULL)
4855                                                 has_default = true;
4856
4857                                         check_reachable((statement_t*)i);
4858                                 }
4859
4860                                 if (has_default)
4861                                         return;
4862                         }
4863
4864                         next = stmt->base.next;
4865                         break;
4866                 }
4867
4868                 case STATEMENT_EXPRESSION: {
4869                         /* Check for noreturn function call */
4870                         expression_t const *const expr = stmt->expression.expression;
4871                         if (!expression_returns(expr))
4872                                 return;
4873
4874                         next = stmt->base.next;
4875                         break;
4876                 }
4877
4878                 case STATEMENT_CONTINUE:
4879                         for (statement_t *parent = stmt;;) {
4880                                 parent = parent->base.parent;
4881                                 if (parent == NULL) /* continue not within loop */
4882                                         return;
4883
4884                                 next = parent;
4885                                 switch (parent->kind) {
4886                                         case STATEMENT_WHILE:    goto continue_while;
4887                                         case STATEMENT_DO_WHILE: goto continue_do_while;
4888                                         case STATEMENT_FOR:      goto continue_for;
4889
4890                                         default: break;
4891                                 }
4892                         }
4893
4894                 case STATEMENT_BREAK:
4895                         for (statement_t *parent = stmt;;) {
4896                                 parent = parent->base.parent;
4897                                 if (parent == NULL) /* break not within loop/switch */
4898                                         return;
4899
4900                                 switch (parent->kind) {
4901                                         case STATEMENT_SWITCH:
4902                                         case STATEMENT_WHILE:
4903                                         case STATEMENT_DO_WHILE:
4904                                         case STATEMENT_FOR:
4905                                                 last = parent;
4906                                                 next = parent->base.next;
4907                                                 goto found_break_parent;
4908
4909                                         default: break;
4910                                 }
4911                         }
4912 found_break_parent:
4913                         break;
4914
4915                 case STATEMENT_COMPUTED_GOTO: {
4916                         if (!expression_returns(stmt->computed_goto.expression))
4917                                 return;
4918
4919                         statement_t *parent = stmt->base.parent;
4920                         if (parent == NULL) /* top level goto */
4921                                 return;
4922                         next = parent;
4923                         break;
4924                 }
4925
4926                 case STATEMENT_GOTO:
4927                         next = stmt->gotos.label->statement;
4928                         if (next == NULL) /* missing label */
4929                                 return;
4930                         break;
4931
4932                 case STATEMENT_LABEL:
4933                         next = stmt->label.statement;
4934                         break;
4935
4936                 case STATEMENT_CASE_LABEL:
4937                         next = stmt->case_label.statement;
4938                         break;
4939
4940                 case STATEMENT_WHILE: {
4941                         while_statement_t const *const whiles = &stmt->whiles;
4942                         expression_t      const *const cond   = whiles->condition;
4943
4944                         if (!expression_returns(cond))
4945                                 return;
4946
4947                         int const val = determine_truth(cond);
4948
4949                         if (val >= 0)
4950                                 check_reachable(whiles->body);
4951
4952                         if (val > 0)
4953                                 return;
4954
4955                         next = stmt->base.next;
4956                         break;
4957                 }
4958
4959                 case STATEMENT_DO_WHILE:
4960                         next = stmt->do_while.body;
4961                         break;
4962
4963                 case STATEMENT_FOR: {
4964                         for_statement_t *const fors = &stmt->fors;
4965
4966                         if (fors->condition_reachable)
4967                                 return;
4968                         fors->condition_reachable = true;
4969
4970                         expression_t const *const cond = fors->condition;
4971
4972                         int val;
4973                         if (cond == NULL) {
4974                                 val = 1;
4975                         } else if (expression_returns(cond)) {
4976                                 val = determine_truth(cond);
4977                         } else {
4978                                 return;
4979                         }
4980
4981                         if (val >= 0)
4982                                 check_reachable(fors->body);
4983
4984                         if (val > 0)
4985                                 return;
4986
4987                         next = stmt->base.next;
4988                         break;
4989                 }
4990
4991                 case STATEMENT_MS_TRY: {
4992                         ms_try_statement_t const *const ms_try = &stmt->ms_try;
4993                         check_reachable(ms_try->try_statement);
4994                         next = ms_try->final_statement;
4995                         break;
4996                 }
4997
4998                 case STATEMENT_LEAVE: {
4999                         statement_t *parent = stmt;
5000                         for (;;) {
5001                                 parent = parent->base.parent;
5002                                 if (parent == NULL) /* __leave not within __try */
5003                                         return;
5004
5005                                 if (parent->kind == STATEMENT_MS_TRY) {
5006                                         last = parent;
5007                                         next = parent->ms_try.final_statement;
5008                                         break;
5009                                 }
5010                         }
5011                         break;
5012                 }
5013
5014                 default:
5015                         panic("invalid statement kind");
5016         }
5017
5018         while (next == NULL) {
5019                 next = last->base.parent;
5020                 if (next == NULL) {
5021                         noreturn_candidate = false;
5022
5023                         type_t *const type = skip_typeref(current_function->base.type);
5024                         assert(is_type_function(type));
5025                         type_t *const ret  = skip_typeref(type->function.return_type);
5026                         if (!is_type_void(ret) &&
5027                             is_type_valid(ret) &&
5028                             !is_main(current_entity)) {
5029                                 source_position_t const *const pos = &stmt->base.source_position;
5030                                 warningf(WARN_RETURN_TYPE, pos, "control reaches end of non-void function");
5031                         }
5032                         return;
5033                 }
5034
5035                 switch (next->kind) {
5036                         case STATEMENT_ERROR:
5037                         case STATEMENT_EMPTY:
5038                         case STATEMENT_DECLARATION:
5039                         case STATEMENT_EXPRESSION:
5040                         case STATEMENT_ASM:
5041                         case STATEMENT_RETURN:
5042                         case STATEMENT_CONTINUE:
5043                         case STATEMENT_BREAK:
5044                         case STATEMENT_COMPUTED_GOTO:
5045                         case STATEMENT_GOTO:
5046                         case STATEMENT_LEAVE:
5047                                 panic("invalid control flow in function");
5048
5049                         case STATEMENT_COMPOUND:
5050                                 if (next->compound.stmt_expr) {
5051                                         reaches_end = true;
5052                                         return;
5053                                 }
5054                                 /* FALLTHROUGH */
5055                         case STATEMENT_IF:
5056                         case STATEMENT_SWITCH:
5057                         case STATEMENT_LABEL:
5058                         case STATEMENT_CASE_LABEL:
5059                                 last = next;
5060                                 next = next->base.next;
5061                                 break;
5062
5063                         case STATEMENT_WHILE: {
5064 continue_while:
5065                                 if (next->base.reachable)
5066                                         return;
5067                                 next->base.reachable = true;
5068
5069                                 while_statement_t const *const whiles = &next->whiles;
5070                                 expression_t      const *const cond   = whiles->condition;
5071
5072                                 if (!expression_returns(cond))
5073                                         return;
5074
5075                                 int const val = determine_truth(cond);
5076
5077                                 if (val >= 0)
5078                                         check_reachable(whiles->body);
5079
5080                                 if (val > 0)
5081                                         return;
5082
5083                                 last = next;
5084                                 next = next->base.next;
5085                                 break;
5086                         }
5087
5088                         case STATEMENT_DO_WHILE: {
5089 continue_do_while:
5090                                 if (next->base.reachable)
5091                                         return;
5092                                 next->base.reachable = true;
5093
5094                                 do_while_statement_t const *const dw   = &next->do_while;
5095                                 expression_t         const *const cond = dw->condition;
5096
5097                                 if (!expression_returns(cond))
5098                                         return;
5099
5100                                 int const val = determine_truth(cond);
5101
5102                                 if (val >= 0)
5103                                         check_reachable(dw->body);
5104
5105                                 if (val > 0)
5106                                         return;
5107
5108                                 last = next;
5109                                 next = next->base.next;
5110                                 break;
5111                         }
5112
5113                         case STATEMENT_FOR: {
5114 continue_for:;
5115                                 for_statement_t *const fors = &next->fors;
5116
5117                                 fors->step_reachable = true;
5118
5119                                 if (fors->condition_reachable)
5120                                         return;
5121                                 fors->condition_reachable = true;
5122
5123                                 expression_t const *const cond = fors->condition;
5124
5125                                 int val;
5126                                 if (cond == NULL) {
5127                                         val = 1;
5128                                 } else if (expression_returns(cond)) {
5129                                         val = determine_truth(cond);
5130                                 } else {
5131                                         return;
5132                                 }
5133
5134                                 if (val >= 0)
5135                                         check_reachable(fors->body);
5136
5137                                 if (val > 0)
5138                                         return;
5139
5140                                 last = next;
5141                                 next = next->base.next;
5142                                 break;
5143                         }
5144
5145                         case STATEMENT_MS_TRY:
5146                                 last = next;
5147                                 next = next->ms_try.final_statement;
5148                                 break;
5149                 }
5150         }
5151
5152         check_reachable(next);
5153 }
5154
5155 static void check_unreachable(statement_t* const stmt, void *const env)
5156 {
5157         (void)env;
5158
5159         switch (stmt->kind) {
5160                 case STATEMENT_DO_WHILE:
5161                         if (!stmt->base.reachable) {
5162                                 expression_t const *const cond = stmt->do_while.condition;
5163                                 if (determine_truth(cond) >= 0) {
5164                                         source_position_t const *const pos = &cond->base.source_position;
5165                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of do-while-loop is unreachable");
5166                                 }
5167                         }
5168                         return;
5169
5170                 case STATEMENT_FOR: {
5171                         for_statement_t const* const fors = &stmt->fors;
5172
5173                         // if init and step are unreachable, cond is unreachable, too
5174                         if (!stmt->base.reachable && !fors->step_reachable) {
5175                                 goto warn_unreachable;
5176                         } else {
5177                                 if (!stmt->base.reachable && fors->initialisation != NULL) {
5178                                         source_position_t const *const pos = &fors->initialisation->base.source_position;
5179                                         warningf(WARN_UNREACHABLE_CODE, pos, "initialisation of for-statement is unreachable");
5180                                 }
5181
5182                                 if (!fors->condition_reachable && fors->condition != NULL) {
5183                                         source_position_t const *const pos = &fors->condition->base.source_position;
5184                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of for-statement is unreachable");
5185                                 }
5186
5187                                 if (!fors->step_reachable && fors->step != NULL) {
5188                                         source_position_t const *const pos = &fors->step->base.source_position;
5189                                         warningf(WARN_UNREACHABLE_CODE, pos, "step of for-statement is unreachable");
5190                                 }
5191                         }
5192                         return;
5193                 }
5194
5195                 case STATEMENT_COMPOUND:
5196                         if (stmt->compound.statements != NULL)
5197                                 return;
5198                         goto warn_unreachable;
5199
5200                 case STATEMENT_DECLARATION: {
5201                         /* Only warn if there is at least one declarator with an initializer.
5202                          * This typically occurs in switch statements. */
5203                         declaration_statement_t const *const decl = &stmt->declaration;
5204                         entity_t                const *      ent  = decl->declarations_begin;
5205                         entity_t                const *const last = decl->declarations_end;
5206                         if (ent != NULL) {
5207                                 for (;; ent = ent->base.next) {
5208                                         if (ent->kind                 == ENTITY_VARIABLE &&
5209                                                         ent->variable.initializer != NULL) {
5210                                                 goto warn_unreachable;
5211                                         }
5212                                         if (ent == last)
5213                                                 return;
5214                                 }
5215                         }
5216                 }
5217
5218                 default:
5219 warn_unreachable:
5220                         if (!stmt->base.reachable) {
5221                                 source_position_t const *const pos = &stmt->base.source_position;
5222                                 warningf(WARN_UNREACHABLE_CODE, pos, "statement is unreachable");
5223                         }
5224                         return;
5225         }
5226 }
5227
5228 static bool is_main(entity_t *entity)
5229 {
5230         static symbol_t *sym_main = NULL;
5231         if (sym_main == NULL) {
5232                 sym_main = symbol_table_insert("main");
5233         }
5234
5235         if (entity->base.symbol != sym_main)
5236                 return false;
5237         /* must be in outermost scope */
5238         if (entity->base.parent_scope != file_scope)
5239                 return false;
5240
5241         return true;
5242 }
5243
5244 static void prepare_main_collect2(entity_t*);
5245
5246 static void parse_external_declaration(void)
5247 {
5248         /* function-definitions and declarations both start with declaration
5249          * specifiers */
5250         add_anchor_token(';');
5251         declaration_specifiers_t specifiers;
5252         parse_declaration_specifiers(&specifiers);
5253         rem_anchor_token(';');
5254
5255         /* must be a declaration */
5256         if (token.kind == ';') {
5257                 parse_anonymous_declaration_rest(&specifiers);
5258                 return;
5259         }
5260
5261         add_anchor_token(',');
5262         add_anchor_token('=');
5263         add_anchor_token(';');
5264         add_anchor_token('{');
5265
5266         /* declarator is common to both function-definitions and declarations */
5267         entity_t *ndeclaration = parse_declarator(&specifiers, DECL_FLAGS_NONE);
5268
5269         rem_anchor_token('{');
5270         rem_anchor_token(';');
5271         rem_anchor_token('=');
5272         rem_anchor_token(',');
5273
5274         /* must be a declaration */
5275         switch (token.kind) {
5276                 case ',':
5277                 case ';':
5278                 case '=':
5279                         parse_declaration_rest(ndeclaration, &specifiers, record_entity,
5280                                         DECL_FLAGS_NONE);
5281                         return;
5282         }
5283
5284         /* must be a function definition */
5285         parse_kr_declaration_list(ndeclaration);
5286
5287         if (token.kind != '{') {
5288                 parse_error_expected("while parsing function definition", '{', NULL);
5289                 eat_until_matching_token(';');
5290                 return;
5291         }
5292
5293         assert(is_declaration(ndeclaration));
5294         type_t *const orig_type = ndeclaration->declaration.type;
5295         type_t *      type      = skip_typeref(orig_type);
5296
5297         if (!is_type_function(type)) {
5298                 if (is_type_valid(type)) {
5299                         errorf(HERE, "declarator '%#N' has a body but is not a function type", ndeclaration);
5300                 }
5301                 eat_block();
5302                 return;
5303         }
5304
5305         source_position_t const *const pos = &ndeclaration->base.source_position;
5306         if (is_typeref(orig_type)) {
5307                 /* §6.9.1:2 */
5308                 errorf(pos, "type of function definition '%#N' is a typedef", ndeclaration);
5309         }
5310
5311         if (is_type_compound(skip_typeref(type->function.return_type))) {
5312                 warningf(WARN_AGGREGATE_RETURN, pos, "'%N' returns an aggregate", ndeclaration);
5313         }
5314         if (type->function.unspecified_parameters) {
5315                 warningf(WARN_OLD_STYLE_DEFINITION, pos, "old-style definition of '%N'", ndeclaration);
5316         } else {
5317                 warningf(WARN_TRADITIONAL, pos, "traditional C rejects ISO C style definition of '%N'", ndeclaration);
5318         }
5319
5320         /* §6.7.5.3:14 a function definition with () means no
5321          * parameters (and not unspecified parameters) */
5322         if (type->function.unspecified_parameters &&
5323                         type->function.parameters == NULL) {
5324                 type_t *copy                          = duplicate_type(type);
5325                 copy->function.unspecified_parameters = false;
5326                 type                                  = identify_new_type(copy);
5327
5328                 ndeclaration->declaration.type = type;
5329         }
5330
5331         entity_t *const entity = record_entity(ndeclaration, true);
5332         assert(entity->kind == ENTITY_FUNCTION);
5333         assert(ndeclaration->kind == ENTITY_FUNCTION);
5334
5335         function_t *const function = &entity->function;
5336         if (ndeclaration != entity) {
5337                 function->parameters = ndeclaration->function.parameters;
5338         }
5339
5340         PUSH_SCOPE(&function->parameters);
5341
5342         entity_t *parameter = function->parameters.entities;
5343         for (; parameter != NULL; parameter = parameter->base.next) {
5344                 if (parameter->base.parent_scope == &ndeclaration->function.parameters) {
5345                         parameter->base.parent_scope = current_scope;
5346                 }
5347                 assert(parameter->base.parent_scope == NULL
5348                                 || parameter->base.parent_scope == current_scope);
5349                 parameter->base.parent_scope = current_scope;
5350                 if (parameter->base.symbol == NULL) {
5351                         errorf(&parameter->base.source_position, "parameter name omitted");
5352                         continue;
5353                 }
5354                 environment_push(parameter);
5355         }
5356
5357         if (function->statement != NULL) {
5358                 parser_error_multiple_definition(entity, HERE);
5359                 eat_block();
5360         } else {
5361                 /* parse function body */
5362                 int         label_stack_top      = label_top();
5363                 function_t *old_current_function = current_function;
5364                 current_function                 = function;
5365                 PUSH_CURRENT_ENTITY(entity);
5366                 PUSH_PARENT(NULL);
5367
5368                 goto_first   = NULL;
5369                 goto_anchor  = &goto_first;
5370                 label_first  = NULL;
5371                 label_anchor = &label_first;
5372
5373                 statement_t *const body = parse_compound_statement(false);
5374                 function->statement = body;
5375                 first_err = true;
5376                 check_labels();
5377                 check_declarations();
5378                 if (is_warn_on(WARN_RETURN_TYPE)      ||
5379                     is_warn_on(WARN_UNREACHABLE_CODE) ||
5380                     (is_warn_on(WARN_MISSING_NORETURN) && !(function->base.modifiers & DM_NORETURN))) {
5381                         noreturn_candidate = true;
5382                         check_reachable(body);
5383                         if (is_warn_on(WARN_UNREACHABLE_CODE))
5384                                 walk_statements(body, check_unreachable, NULL);
5385                         if (noreturn_candidate &&
5386                             !(function->base.modifiers & DM_NORETURN)) {
5387                                 source_position_t const *const pos = &body->base.source_position;
5388                                 warningf(WARN_MISSING_NORETURN, pos, "function '%#N' is candidate for attribute 'noreturn'", entity);
5389                         }
5390                 }
5391
5392                 if (is_main(entity)) {
5393                         /* Force main to C linkage. */
5394                         type_t *const type = entity->declaration.type;
5395                         assert(is_type_function(type));
5396                         if (type->function.linkage != LINKAGE_C) {
5397                                 type_t *new_type           = duplicate_type(type);
5398                                 new_type->function.linkage = LINKAGE_C;
5399                                 entity->declaration.type   = identify_new_type(new_type);
5400                         }
5401
5402                         if (enable_main_collect2_hack)
5403                                 prepare_main_collect2(entity);
5404                 }
5405
5406                 POP_CURRENT_ENTITY();
5407                 POP_PARENT();
5408                 assert(current_function == function);
5409                 current_function = old_current_function;
5410                 label_pop_to(label_stack_top);
5411         }
5412
5413         POP_SCOPE();
5414 }
5415
5416 static entity_t *find_compound_entry(compound_t *compound, symbol_t *symbol)
5417 {
5418         entity_t *iter = compound->members.entities;
5419         for (; iter != NULL; iter = iter->base.next) {
5420                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5421                         continue;
5422
5423                 if (iter->base.symbol == symbol) {
5424                         return iter;
5425                 } else if (iter->base.symbol == NULL) {
5426                         /* search in anonymous structs and unions */
5427                         type_t *type = skip_typeref(iter->declaration.type);
5428                         if (is_type_compound(type)) {
5429                                 if (find_compound_entry(type->compound.compound, symbol)
5430                                                 != NULL)
5431                                         return iter;
5432                         }
5433                         continue;
5434                 }
5435         }
5436
5437         return NULL;
5438 }
5439
5440 static void check_deprecated(const source_position_t *source_position,
5441                              const entity_t *entity)
5442 {
5443         if (!is_declaration(entity))
5444                 return;
5445         if ((entity->declaration.modifiers & DM_DEPRECATED) == 0)
5446                 return;
5447
5448         source_position_t const *const epos = &entity->base.source_position;
5449         char              const *const msg  = get_deprecated_string(entity->declaration.attributes);
5450         if (msg != NULL) {
5451                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P): \"%s\"", entity, epos, msg);
5452         } else {
5453                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P)", entity, epos);
5454         }
5455 }
5456
5457
5458 static expression_t *create_select(const source_position_t *pos,
5459                                    expression_t *addr,
5460                                    type_qualifiers_t qualifiers,
5461                                                                    entity_t *entry)
5462 {
5463         assert(entry->kind == ENTITY_COMPOUND_MEMBER);
5464
5465         check_deprecated(pos, entry);
5466
5467         expression_t *select          = allocate_expression_zero(EXPR_SELECT);
5468         select->select.compound       = addr;
5469         select->select.compound_entry = entry;
5470
5471         type_t *entry_type = entry->declaration.type;
5472         type_t *res_type   = get_qualified_type(entry_type, qualifiers);
5473
5474         /* bitfields need special treatment */
5475         if (entry->compound_member.bitfield) {
5476                 unsigned bit_size = entry->compound_member.bit_size;
5477                 /* if fewer bits than an int, convert to int (see §6.3.1.1) */
5478                 if (bit_size < get_atomic_type_size(ATOMIC_TYPE_INT) * BITS_PER_BYTE) {
5479                         res_type = type_int;
5480                 }
5481         }
5482
5483         /* we always do the auto-type conversions; the & and sizeof parser contains
5484          * code to revert this! */
5485         select->base.type = automatic_type_conversion(res_type);
5486
5487
5488         return select;
5489 }
5490
5491 /**
5492  * Find entry with symbol in compound. Search anonymous structs and unions and
5493  * creates implicit select expressions for them.
5494  * Returns the adress for the innermost compound.
5495  */
5496 static expression_t *find_create_select(const source_position_t *pos,
5497                                         expression_t *addr,
5498                                         type_qualifiers_t qualifiers,
5499                                         compound_t *compound, symbol_t *symbol)
5500 {
5501         entity_t *iter = compound->members.entities;
5502         for (; iter != NULL; iter = iter->base.next) {
5503                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5504                         continue;
5505
5506                 symbol_t *iter_symbol = iter->base.symbol;
5507                 if (iter_symbol == NULL) {
5508                         type_t *type = iter->declaration.type;
5509                         if (type->kind != TYPE_COMPOUND_STRUCT
5510                                         && type->kind != TYPE_COMPOUND_UNION)
5511                                 continue;
5512
5513                         compound_t *sub_compound = type->compound.compound;
5514
5515                         if (find_compound_entry(sub_compound, symbol) == NULL)
5516                                 continue;
5517
5518                         expression_t *sub_addr = create_select(pos, addr, qualifiers, iter);
5519                         sub_addr->base.source_position = *pos;
5520                         sub_addr->base.implicit        = true;
5521                         return find_create_select(pos, sub_addr, qualifiers, sub_compound,
5522                                                   symbol);
5523                 }
5524
5525                 if (iter_symbol == symbol) {
5526                         return create_select(pos, addr, qualifiers, iter);
5527                 }
5528         }
5529
5530         return NULL;
5531 }
5532
5533 static void parse_bitfield_member(entity_t *entity)
5534 {
5535         eat(':');
5536
5537         expression_t *size = parse_constant_expression();
5538         long          size_long;
5539
5540         assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5541         type_t *type = entity->declaration.type;
5542         if (!is_type_integer(skip_typeref(type))) {
5543                 errorf(HERE, "bitfield base type '%T' is not an integer type",
5544                            type);
5545         }
5546
5547         if (is_constant_expression(size) != EXPR_CLASS_CONSTANT) {
5548                 /* error already reported by parse_constant_expression */
5549                 size_long = get_type_size(type) * 8;
5550         } else {
5551                 size_long = fold_constant_to_int(size);
5552
5553                 const symbol_t *symbol = entity->base.symbol;
5554                 const symbol_t *user_symbol
5555                         = symbol == NULL ? sym_anonymous : symbol;
5556                 unsigned bit_size = get_type_size(type) * 8;
5557                 if (size_long < 0) {
5558                         errorf(HERE, "negative width in bit-field '%Y'", user_symbol);
5559                 } else if (size_long == 0 && symbol != NULL) {
5560                         errorf(HERE, "zero width for bit-field '%Y'", user_symbol);
5561                 } else if (bit_size > 0 && (unsigned)size_long > bit_size) {
5562                         errorf(HERE, "width of bitfield '%Y' exceeds its type",
5563                                    user_symbol);
5564                 } else {
5565                         /* hope that people don't invent crazy types with more bits
5566                          * than our struct can hold */
5567                         assert(size_long <
5568                                    (1 << sizeof(entity->compound_member.bit_size)*8));
5569                 }
5570         }
5571
5572         entity->compound_member.bitfield = true;
5573         entity->compound_member.bit_size = (unsigned char)size_long;
5574 }
5575
5576 static void parse_compound_declarators(compound_t *compound,
5577                 const declaration_specifiers_t *specifiers)
5578 {
5579         add_anchor_token(';');
5580         add_anchor_token(',');
5581         do {
5582                 entity_t *entity;
5583
5584                 if (token.kind == ':') {
5585                         /* anonymous bitfield */
5586                         type_t *type = specifiers->type;
5587                         entity_t *const entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, NULL, HERE);
5588                         entity->declaration.declared_storage_class = STORAGE_CLASS_NONE;
5589                         entity->declaration.storage_class          = STORAGE_CLASS_NONE;
5590                         entity->declaration.type                   = type;
5591
5592                         parse_bitfield_member(entity);
5593
5594                         attribute_t  *attributes = parse_attributes(NULL);
5595                         attribute_t **anchor     = &attributes;
5596                         while (*anchor != NULL)
5597                                 anchor = &(*anchor)->next;
5598                         *anchor = specifiers->attributes;
5599                         if (attributes != NULL) {
5600                                 handle_entity_attributes(attributes, entity);
5601                         }
5602                         entity->declaration.attributes = attributes;
5603
5604                         append_entity(&compound->members, entity);
5605                 } else {
5606                         entity = parse_declarator(specifiers,
5607                                         DECL_MAY_BE_ABSTRACT | DECL_CREATE_COMPOUND_MEMBER);
5608                         source_position_t const *const pos = &entity->base.source_position;
5609                         if (entity->kind == ENTITY_TYPEDEF) {
5610                                 errorf(pos, "typedef not allowed as compound member");
5611                         } else {
5612                                 assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5613
5614                                 /* make sure we don't define a symbol multiple times */
5615                                 symbol_t *symbol = entity->base.symbol;
5616                                 if (symbol != NULL) {
5617                                         entity_t *prev = find_compound_entry(compound, symbol);
5618                                         if (prev != NULL) {
5619                                                 source_position_t const *const ppos = &prev->base.source_position;
5620                                                 errorf(pos, "multiple declarations of '%N' (declared %P)", entity, ppos);
5621                                         }
5622                                 }
5623
5624                                 if (token.kind == ':') {
5625                                         parse_bitfield_member(entity);
5626
5627                                         attribute_t *attributes = parse_attributes(NULL);
5628                                         handle_entity_attributes(attributes, entity);
5629                                 } else {
5630                                         type_t *orig_type = entity->declaration.type;
5631                                         type_t *type      = skip_typeref(orig_type);
5632                                         if (is_type_function(type)) {
5633                                                 errorf(pos, "'%N' must not have function type '%T'", entity, orig_type);
5634                                         } else if (is_type_incomplete(type)) {
5635                                                 /* §6.7.2.1:16 flexible array member */
5636                                                 if (!is_type_array(type)       ||
5637                                                                 token.kind          != ';' ||
5638                                                                 look_ahead(1)->kind != '}') {
5639                                                         errorf(pos, "'%N' has incomplete type '%T'", entity, orig_type);
5640                                                 } else if (compound->members.entities == NULL) {
5641                                                         errorf(pos, "flexible array member in otherwise empty struct");
5642                                                 }
5643                                         }
5644                                 }
5645
5646                                 append_entity(&compound->members, entity);
5647                         }
5648                 }
5649         } while (next_if(','));
5650         rem_anchor_token(',');
5651         rem_anchor_token(';');
5652         expect(';');
5653
5654         anonymous_entity = NULL;
5655 }
5656
5657 static void parse_compound_type_entries(compound_t *compound)
5658 {
5659         eat('{');
5660         add_anchor_token('}');
5661
5662         for (;;) {
5663                 switch (token.kind) {
5664                         DECLARATION_START
5665                         case T___extension__:
5666                         case T_IDENTIFIER: {
5667                                 PUSH_EXTENSION();
5668                                 declaration_specifiers_t specifiers;
5669                                 parse_declaration_specifiers(&specifiers);
5670                                 parse_compound_declarators(compound, &specifiers);
5671                                 POP_EXTENSION();
5672                                 break;
5673                         }
5674
5675                         default:
5676                                 rem_anchor_token('}');
5677                                 expect('}');
5678                                 /* §6.7.2.1:7 */
5679                                 compound->complete = true;
5680                                 return;
5681                 }
5682         }
5683 }
5684
5685 static type_t *parse_typename(void)
5686 {
5687         declaration_specifiers_t specifiers;
5688         parse_declaration_specifiers(&specifiers);
5689         if (specifiers.storage_class != STORAGE_CLASS_NONE
5690                         || specifiers.thread_local) {
5691                 /* TODO: improve error message, user does probably not know what a
5692                  * storage class is...
5693                  */
5694                 errorf(&specifiers.source_position, "typename must not have a storage class");
5695         }
5696
5697         type_t *result = parse_abstract_declarator(specifiers.type);
5698
5699         return result;
5700 }
5701
5702
5703
5704
5705 typedef expression_t* (*parse_expression_function)(void);
5706 typedef expression_t* (*parse_expression_infix_function)(expression_t *left);
5707
5708 typedef struct expression_parser_function_t expression_parser_function_t;
5709 struct expression_parser_function_t {
5710         parse_expression_function        parser;
5711         precedence_t                     infix_precedence;
5712         parse_expression_infix_function  infix_parser;
5713 };
5714
5715 static expression_parser_function_t expression_parsers[T_LAST_TOKEN];
5716
5717 static type_t *get_string_type(void)
5718 {
5719         return is_warn_on(WARN_WRITE_STRINGS) ? type_const_char_ptr : type_char_ptr;
5720 }
5721
5722 static type_t *get_wide_string_type(void)
5723 {
5724         return is_warn_on(WARN_WRITE_STRINGS) ? type_const_wchar_t_ptr : type_wchar_t_ptr;
5725 }
5726
5727 /**
5728  * Parse a string constant.
5729  */
5730 static expression_t *parse_string_literal(void)
5731 {
5732         string_encoding_t       enc;
5733         source_position_t const pos = *HERE;
5734         string_t          const res = concat_string_literals(&enc);
5735
5736         expression_t *literal;
5737         if (enc != STRING_ENCODING_CHAR) {
5738                 literal = allocate_expression_zero(EXPR_WIDE_STRING_LITERAL);
5739                 literal->base.type = get_wide_string_type();
5740         } else {
5741                 literal = allocate_expression_zero(EXPR_STRING_LITERAL);
5742                 literal->base.type = get_string_type();
5743         }
5744         literal->base.source_position = pos;
5745         literal->literal.value        = res;
5746
5747         return literal;
5748 }
5749
5750 /**
5751  * Parse a boolean constant.
5752  */
5753 static expression_t *parse_boolean_literal(bool value)
5754 {
5755         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_BOOLEAN);
5756         literal->base.type           = type_bool;
5757         literal->literal.value.begin = value ? "true" : "false";
5758         literal->literal.value.size  = value ? 4 : 5;
5759
5760         eat(value ? T_true : T_false);
5761         return literal;
5762 }
5763
5764 static void warn_traditional_suffix(void)
5765 {
5766         warningf(WARN_TRADITIONAL, HERE, "traditional C rejects the '%S' suffix",
5767                  &token.number.suffix);
5768 }
5769
5770 static void check_integer_suffix(void)
5771 {
5772         const string_t *suffix = &token.number.suffix;
5773         if (suffix->size == 0)
5774                 return;
5775
5776         bool not_traditional = false;
5777         const char *c = suffix->begin;
5778         if (*c == 'l' || *c == 'L') {
5779                 ++c;
5780                 if (*c == *(c-1)) {
5781                         not_traditional = true;
5782                         ++c;
5783                         if (*c == 'u' || *c == 'U') {
5784                                 ++c;
5785                         }
5786                 } else if (*c == 'u' || *c == 'U') {
5787                         not_traditional = true;
5788                         ++c;
5789                 }
5790         } else if (*c == 'u' || *c == 'U') {
5791                 not_traditional = true;
5792                 ++c;
5793                 if (*c == 'l' || *c == 'L') {
5794                         ++c;
5795                         if (*c == *(c-1)) {
5796                                 ++c;
5797                         }
5798                 }
5799         }
5800         if (*c != '\0') {
5801                 errorf(HERE, "invalid suffix '%S' on integer constant", suffix);
5802         } else if (not_traditional) {
5803                 warn_traditional_suffix();
5804         }
5805 }
5806
5807 static type_t *check_floatingpoint_suffix(void)
5808 {
5809         const string_t *suffix = &token.number.suffix;
5810         type_t         *type   = type_double;
5811         if (suffix->size == 0)
5812                 return type;
5813
5814         bool not_traditional = false;
5815         const char *c = suffix->begin;
5816         if (*c == 'f' || *c == 'F') {
5817                 ++c;
5818                 type = type_float;
5819         } else if (*c == 'l' || *c == 'L') {
5820                 ++c;
5821                 type = type_long_double;
5822         }
5823         if (*c != '\0') {
5824                 errorf(HERE, "invalid suffix '%S' on floatingpoint constant", suffix);
5825         } else if (not_traditional) {
5826                 warn_traditional_suffix();
5827         }
5828
5829         return type;
5830 }
5831
5832 /**
5833  * Parse an integer constant.
5834  */
5835 static expression_t *parse_number_literal(void)
5836 {
5837         expression_kind_t  kind;
5838         type_t            *type;
5839
5840         switch (token.kind) {
5841         case T_INTEGER:
5842                 kind = EXPR_LITERAL_INTEGER;
5843                 check_integer_suffix();
5844                 type = type_int;
5845                 break;
5846
5847         case T_FLOATINGPOINT:
5848                 kind = EXPR_LITERAL_FLOATINGPOINT;
5849                 type = check_floatingpoint_suffix();
5850                 break;
5851
5852         default:
5853                 panic("unexpected token type in parse_number_literal");
5854         }
5855
5856         expression_t *literal = allocate_expression_zero(kind);
5857         literal->base.type      = type;
5858         literal->literal.value  = token.number.number;
5859         literal->literal.suffix = token.number.suffix;
5860         next_token();
5861
5862         /* integer type depends on the size of the number and the size
5863          * representable by the types. The backend/codegeneration has to determine
5864          * that
5865          */
5866         determine_literal_type(&literal->literal);
5867         return literal;
5868 }
5869
5870 /**
5871  * Parse a character constant.
5872  */
5873 static expression_t *parse_character_constant(void)
5874 {
5875         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_CHARACTER);
5876         literal->base.type     = c_mode & _CXX ? type_char : type_int;
5877         literal->literal.value = token.string.string;
5878
5879         size_t len = literal->literal.value.size;
5880         if (len > 1) {
5881                 if (!GNU_MODE && !(c_mode & _C99)) {
5882                         errorf(HERE, "more than 1 character in character constant");
5883                 } else {
5884                         literal->base.type = type_int;
5885                         warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5886                 }
5887         }
5888
5889         eat(T_CHARACTER_CONSTANT);
5890         return literal;
5891 }
5892
5893 /**
5894  * Parse a wide character constant.
5895  */
5896 static expression_t *parse_wide_character_constant(void)
5897 {
5898         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_WIDE_CHARACTER);
5899         literal->base.type     = type_int;
5900         literal->literal.value = token.string.string;
5901
5902         size_t len = wstrlen(&literal->literal.value);
5903         if (len > 1) {
5904                 warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5905         }
5906
5907         eat(T_WIDE_CHARACTER_CONSTANT);
5908         return literal;
5909 }
5910
5911 static entity_t *create_implicit_function(symbol_t *symbol, source_position_t const *const pos)
5912 {
5913         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
5914         ntype->function.return_type            = type_int;
5915         ntype->function.unspecified_parameters = true;
5916         ntype->function.linkage                = LINKAGE_C;
5917         type_t *type                           = identify_new_type(ntype);
5918
5919         entity_t *const entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, symbol, pos);
5920         entity->declaration.storage_class          = STORAGE_CLASS_EXTERN;
5921         entity->declaration.declared_storage_class = STORAGE_CLASS_EXTERN;
5922         entity->declaration.type                   = type;
5923         entity->declaration.implicit               = true;
5924
5925         if (current_scope != NULL)
5926                 record_entity(entity, false);
5927
5928         return entity;
5929 }
5930
5931 /**
5932  * Performs automatic type cast as described in §6.3.2.1.
5933  *
5934  * @param orig_type  the original type
5935  */
5936 static type_t *automatic_type_conversion(type_t *orig_type)
5937 {
5938         type_t *type = skip_typeref(orig_type);
5939         if (is_type_array(type)) {
5940                 array_type_t *array_type   = &type->array;
5941                 type_t       *element_type = array_type->element_type;
5942                 unsigned      qualifiers   = array_type->base.qualifiers;
5943
5944                 return make_pointer_type(element_type, qualifiers);
5945         }
5946
5947         if (is_type_function(type)) {
5948                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
5949         }
5950
5951         return orig_type;
5952 }
5953
5954 /**
5955  * reverts the automatic casts of array to pointer types and function
5956  * to function-pointer types as defined §6.3.2.1
5957  */
5958 type_t *revert_automatic_type_conversion(const expression_t *expression)
5959 {
5960         switch (expression->kind) {
5961         case EXPR_REFERENCE: {
5962                 entity_t *entity = expression->reference.entity;
5963                 if (is_declaration(entity)) {
5964                         return entity->declaration.type;
5965                 } else if (entity->kind == ENTITY_ENUM_VALUE) {
5966                         return entity->enum_value.enum_type;
5967                 } else {
5968                         panic("no declaration or enum in reference");
5969                 }
5970         }
5971
5972         case EXPR_SELECT: {
5973                 entity_t *entity = expression->select.compound_entry;
5974                 assert(is_declaration(entity));
5975                 type_t   *type   = entity->declaration.type;
5976                 return get_qualified_type(type, expression->base.type->base.qualifiers);
5977         }
5978
5979         case EXPR_UNARY_DEREFERENCE: {
5980                 const expression_t *const value = expression->unary.value;
5981                 type_t             *const type  = skip_typeref(value->base.type);
5982                 if (!is_type_pointer(type))
5983                         return type_error_type;
5984                 return type->pointer.points_to;
5985         }
5986
5987         case EXPR_ARRAY_ACCESS: {
5988                 const expression_t *array_ref = expression->array_access.array_ref;
5989                 type_t             *type_left = skip_typeref(array_ref->base.type);
5990                 if (!is_type_pointer(type_left))
5991                         return type_error_type;
5992                 return type_left->pointer.points_to;
5993         }
5994
5995         case EXPR_STRING_LITERAL: {
5996                 size_t size = expression->string_literal.value.size;
5997                 return make_array_type(type_char, size, TYPE_QUALIFIER_NONE);
5998         }
5999
6000         case EXPR_WIDE_STRING_LITERAL: {
6001                 size_t size = wstrlen(&expression->string_literal.value);
6002                 return make_array_type(type_wchar_t, size, TYPE_QUALIFIER_NONE);
6003         }
6004
6005         case EXPR_COMPOUND_LITERAL:
6006                 return expression->compound_literal.type;
6007
6008         default:
6009                 break;
6010         }
6011         return expression->base.type;
6012 }
6013
6014 /**
6015  * Find an entity matching a symbol in a scope.
6016  * Uses current scope if scope is NULL
6017  */
6018 static entity_t *lookup_entity(const scope_t *scope, symbol_t *symbol,
6019                                namespace_tag_t namespc)
6020 {
6021         if (scope == NULL) {
6022                 return get_entity(symbol, namespc);
6023         }
6024
6025         /* we should optimize here, if scope grows above a certain size we should
6026            construct a hashmap here... */
6027         entity_t *entity = scope->entities;
6028         for ( ; entity != NULL; entity = entity->base.next) {
6029                 if (entity->base.symbol == symbol
6030                     && (namespace_tag_t)entity->base.namespc == namespc)
6031                         break;
6032         }
6033
6034         return entity;
6035 }
6036
6037 static entity_t *parse_qualified_identifier(void)
6038 {
6039         /* namespace containing the symbol */
6040         symbol_t          *symbol;
6041         source_position_t  pos;
6042         const scope_t     *lookup_scope = NULL;
6043
6044         if (next_if(T_COLONCOLON))
6045                 lookup_scope = &unit->scope;
6046
6047         entity_t *entity;
6048         while (true) {
6049                 symbol = expect_identifier("while parsing identifier", &pos);
6050                 if (!symbol)
6051                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6052
6053                 /* lookup entity */
6054                 entity = lookup_entity(lookup_scope, symbol, NAMESPACE_NORMAL);
6055
6056                 if (!next_if(T_COLONCOLON))
6057                         break;
6058
6059                 switch (entity->kind) {
6060                 case ENTITY_NAMESPACE:
6061                         lookup_scope = &entity->namespacee.members;
6062                         break;
6063                 case ENTITY_STRUCT:
6064                 case ENTITY_UNION:
6065                 case ENTITY_CLASS:
6066                         lookup_scope = &entity->compound.members;
6067                         break;
6068                 default:
6069                         errorf(&pos, "'%Y' must be a namespace, class, struct or union (but is a %s)",
6070                                symbol, get_entity_kind_name(entity->kind));
6071
6072                         /* skip further qualifications */
6073                         while (next_if(T_IDENTIFIER) && next_if(T_COLONCOLON)) {}
6074
6075                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6076                 }
6077         }
6078
6079         if (entity == NULL) {
6080                 if (!strict_mode && token.kind == '(') {
6081                         /* an implicitly declared function */
6082                         entity = create_implicit_function(symbol, &pos);
6083                         warningf(WARN_IMPLICIT_FUNCTION_DECLARATION, &pos, "implicit declaration of '%N'", entity);
6084                 } else {
6085                         errorf(&pos, "unknown identifier '%Y' found.", symbol);
6086                         entity = create_error_entity(symbol, ENTITY_VARIABLE);
6087                 }
6088         }
6089
6090         return entity;
6091 }
6092
6093 static expression_t *parse_reference(void)
6094 {
6095         source_position_t const pos    = *HERE;
6096         entity_t         *const entity = parse_qualified_identifier();
6097
6098         type_t *orig_type;
6099         if (is_declaration(entity)) {
6100                 orig_type = entity->declaration.type;
6101         } else if (entity->kind == ENTITY_ENUM_VALUE) {
6102                 orig_type = entity->enum_value.enum_type;
6103         } else {
6104                 panic("expected declaration or enum value in reference");
6105         }
6106
6107         /* we always do the auto-type conversions; the & and sizeof parser contains
6108          * code to revert this! */
6109         type_t *type = automatic_type_conversion(orig_type);
6110
6111         expression_kind_t kind = EXPR_REFERENCE;
6112         if (entity->kind == ENTITY_ENUM_VALUE)
6113                 kind = EXPR_ENUM_CONSTANT;
6114
6115         expression_t *expression         = allocate_expression_zero(kind);
6116         expression->base.source_position = pos;
6117         expression->base.type            = type;
6118         expression->reference.entity     = entity;
6119
6120         /* this declaration is used */
6121         if (is_declaration(entity)) {
6122                 entity->declaration.used = true;
6123         }
6124
6125         if (entity->base.parent_scope != file_scope
6126                 && (current_function != NULL
6127                         && entity->base.parent_scope->depth < current_function->parameters.depth)
6128                 && (entity->kind == ENTITY_VARIABLE || entity->kind == ENTITY_PARAMETER)) {
6129                 /* access of a variable from an outer function */
6130                 entity->variable.address_taken = true;
6131                 current_function->need_closure = true;
6132         }
6133
6134         check_deprecated(&pos, entity);
6135
6136         return expression;
6137 }
6138
6139 static bool semantic_cast(expression_t *cast)
6140 {
6141         expression_t            *expression      = cast->unary.value;
6142         type_t                  *orig_dest_type  = cast->base.type;
6143         type_t                  *orig_type_right = expression->base.type;
6144         type_t            const *dst_type        = skip_typeref(orig_dest_type);
6145         type_t            const *src_type        = skip_typeref(orig_type_right);
6146         source_position_t const *pos             = &cast->base.source_position;
6147
6148         /* §6.5.4 A (void) cast is explicitly permitted, more for documentation than for utility. */
6149         if (is_type_void(dst_type))
6150                 return true;
6151
6152         /* only integer and pointer can be casted to pointer */
6153         if (is_type_pointer(dst_type)  &&
6154             !is_type_pointer(src_type) &&
6155             !is_type_integer(src_type) &&
6156             is_type_valid(src_type)) {
6157                 errorf(pos, "cannot convert type '%T' to a pointer type", orig_type_right);
6158                 return false;
6159         }
6160
6161         if (!is_type_scalar(dst_type) && is_type_valid(dst_type)) {
6162                 errorf(pos, "conversion to non-scalar type '%T' requested", orig_dest_type);
6163                 return false;
6164         }
6165
6166         if (!is_type_scalar(src_type) && is_type_valid(src_type)) {
6167                 errorf(pos, "conversion from non-scalar type '%T' requested", orig_type_right);
6168                 return false;
6169         }
6170
6171         if (is_type_pointer(src_type) && is_type_pointer(dst_type)) {
6172                 type_t *src = skip_typeref(src_type->pointer.points_to);
6173                 type_t *dst = skip_typeref(dst_type->pointer.points_to);
6174                 unsigned missing_qualifiers =
6175                         src->base.qualifiers & ~dst->base.qualifiers;
6176                 if (missing_qualifiers != 0) {
6177                         warningf(WARN_CAST_QUAL, pos, "cast discards qualifiers '%Q' in pointer target type of '%T'", missing_qualifiers, orig_type_right);
6178                 }
6179         }
6180         return true;
6181 }
6182
6183 static expression_t *parse_compound_literal(source_position_t const *const pos, type_t *type)
6184 {
6185         expression_t *expression = allocate_expression_zero(EXPR_COMPOUND_LITERAL);
6186         expression->base.source_position = *pos;
6187
6188         parse_initializer_env_t env;
6189         env.type             = type;
6190         env.entity           = NULL;
6191         env.must_be_constant = false;
6192         initializer_t *initializer = parse_initializer(&env);
6193         type = env.type;
6194
6195         expression->compound_literal.initializer = initializer;
6196         expression->compound_literal.type        = type;
6197         expression->base.type                    = automatic_type_conversion(type);
6198
6199         return expression;
6200 }
6201
6202 /**
6203  * Parse a cast expression.
6204  */
6205 static expression_t *parse_cast(void)
6206 {
6207         source_position_t const pos = *HERE;
6208
6209         eat('(');
6210         add_anchor_token(')');
6211
6212         type_t *type = parse_typename();
6213
6214         rem_anchor_token(')');
6215         expect(')');
6216
6217         if (token.kind == '{') {
6218                 return parse_compound_literal(&pos, type);
6219         }
6220
6221         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
6222         cast->base.source_position = pos;
6223
6224         expression_t *value = parse_subexpression(PREC_CAST);
6225         cast->base.type   = type;
6226         cast->unary.value = value;
6227
6228         if (! semantic_cast(cast)) {
6229                 /* TODO: record the error in the AST. else it is impossible to detect it */
6230         }
6231
6232         return cast;
6233 }
6234
6235 /**
6236  * Parse a statement expression.
6237  */
6238 static expression_t *parse_statement_expression(void)
6239 {
6240         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
6241
6242         eat('(');
6243         add_anchor_token(')');
6244
6245         statement_t *statement          = parse_compound_statement(true);
6246         statement->compound.stmt_expr   = true;
6247         expression->statement.statement = statement;
6248
6249         /* find last statement and use its type */
6250         type_t *type = type_void;
6251         const statement_t *stmt = statement->compound.statements;
6252         if (stmt != NULL) {
6253                 while (stmt->base.next != NULL)
6254                         stmt = stmt->base.next;
6255
6256                 if (stmt->kind == STATEMENT_EXPRESSION) {
6257                         type = stmt->expression.expression->base.type;
6258                 }
6259         } else {
6260                 source_position_t const *const pos = &expression->base.source_position;
6261                 warningf(WARN_OTHER, pos, "empty statement expression ({})");
6262         }
6263         expression->base.type = type;
6264
6265         rem_anchor_token(')');
6266         expect(')');
6267         return expression;
6268 }
6269
6270 /**
6271  * Parse a parenthesized expression.
6272  */
6273 static expression_t *parse_parenthesized_expression(void)
6274 {
6275         token_t const* const la1 = look_ahead(1);
6276         switch (la1->kind) {
6277         case '{':
6278                 /* gcc extension: a statement expression */
6279                 return parse_statement_expression();
6280
6281         case T_IDENTIFIER:
6282                 if (is_typedef_symbol(la1->base.symbol)) {
6283         DECLARATION_START
6284                         return parse_cast();
6285                 }
6286         }
6287
6288         eat('(');
6289         add_anchor_token(')');
6290         expression_t *result = parse_expression();
6291         result->base.parenthesized = true;
6292         rem_anchor_token(')');
6293         expect(')');
6294
6295         return result;
6296 }
6297
6298 static expression_t *parse_function_keyword(funcname_kind_t const kind)
6299 {
6300         if (current_function == NULL) {
6301                 errorf(HERE, "'%K' used outside of a function", &token);
6302         }
6303
6304         expression_t *expression  = allocate_expression_zero(EXPR_FUNCNAME);
6305         expression->base.type     = type_char_ptr;
6306         expression->funcname.kind = kind;
6307
6308         next_token();
6309
6310         return expression;
6311 }
6312
6313 static designator_t *parse_designator(void)
6314 {
6315         designator_t *const result = allocate_ast_zero(sizeof(result[0]));
6316         result->symbol = expect_identifier("while parsing member designator", &result->source_position);
6317         if (!result->symbol)
6318                 return NULL;
6319
6320         designator_t *last_designator = result;
6321         while (true) {
6322                 if (next_if('.')) {
6323                         designator_t *const designator = allocate_ast_zero(sizeof(result[0]));
6324                         designator->symbol = expect_identifier("while parsing member designator", &designator->source_position);
6325                         if (!designator->symbol)
6326                                 return NULL;
6327
6328                         last_designator->next = designator;
6329                         last_designator       = designator;
6330                         continue;
6331                 }
6332                 if (next_if('[')) {
6333                         add_anchor_token(']');
6334                         designator_t *designator    = allocate_ast_zero(sizeof(result[0]));
6335                         designator->source_position = *HERE;
6336                         designator->array_index     = parse_expression();
6337                         rem_anchor_token(']');
6338                         expect(']');
6339                         if (designator->array_index == NULL) {
6340                                 return NULL;
6341                         }
6342
6343                         last_designator->next = designator;
6344                         last_designator       = designator;
6345                         continue;
6346                 }
6347                 break;
6348         }
6349
6350         return result;
6351 }
6352
6353 /**
6354  * Parse the __builtin_offsetof() expression.
6355  */
6356 static expression_t *parse_offsetof(void)
6357 {
6358         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
6359         expression->base.type    = type_size_t;
6360
6361         eat(T___builtin_offsetof);
6362
6363         add_anchor_token(')');
6364         add_anchor_token(',');
6365         expect('(');
6366         type_t *type = parse_typename();
6367         rem_anchor_token(',');
6368         expect(',');
6369         designator_t *designator = parse_designator();
6370         rem_anchor_token(')');
6371         expect(')');
6372
6373         expression->offsetofe.type       = type;
6374         expression->offsetofe.designator = designator;
6375
6376         type_path_t path;
6377         memset(&path, 0, sizeof(path));
6378         path.top_type = type;
6379         path.path     = NEW_ARR_F(type_path_entry_t, 0);
6380
6381         descend_into_subtype(&path);
6382
6383         if (!walk_designator(&path, designator, true)) {
6384                 return create_error_expression();
6385         }
6386
6387         DEL_ARR_F(path.path);
6388
6389         return expression;
6390 }
6391
6392 static bool is_last_parameter(expression_t *const param)
6393 {
6394         if (param->kind == EXPR_REFERENCE) {
6395                 entity_t *const entity = param->reference.entity;
6396                 if (entity->kind == ENTITY_PARAMETER &&
6397                     !entity->base.next               &&
6398                     entity->base.parent_scope == &current_function->parameters) {
6399                         return true;
6400                 }
6401         }
6402
6403         if (!is_type_valid(skip_typeref(param->base.type)))
6404                 return true;
6405
6406         return false;
6407 }
6408
6409 /**
6410  * Parses a __builtin_va_start() expression.
6411  */
6412 static expression_t *parse_va_start(void)
6413 {
6414         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
6415
6416         eat(T___builtin_va_start);
6417
6418         add_anchor_token(')');
6419         add_anchor_token(',');
6420         expect('(');
6421         expression->va_starte.ap = parse_assignment_expression();
6422         rem_anchor_token(',');
6423         expect(',');
6424         expression_t *const param = parse_assignment_expression();
6425         expression->va_starte.parameter = param;
6426         rem_anchor_token(')');
6427         expect(')');
6428
6429         if (!current_function) {
6430                 errorf(&expression->base.source_position, "'va_start' used outside of function");
6431         } else if (!current_function->base.type->function.variadic) {
6432                 errorf(&expression->base.source_position, "'va_start' used in non-variadic function");
6433         } else if (!is_last_parameter(param)) {
6434                 errorf(&param->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
6435         }
6436
6437         return expression;
6438 }
6439
6440 /**
6441  * Parses a __builtin_va_arg() expression.
6442  */
6443 static expression_t *parse_va_arg(void)
6444 {
6445         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
6446
6447         eat(T___builtin_va_arg);
6448
6449         add_anchor_token(')');
6450         add_anchor_token(',');
6451         expect('(');
6452         call_argument_t ap;
6453         ap.expression = parse_assignment_expression();
6454         expression->va_arge.ap = ap.expression;
6455         check_call_argument(type_valist, &ap, 1);
6456
6457         rem_anchor_token(',');
6458         expect(',');
6459         expression->base.type = parse_typename();
6460         rem_anchor_token(')');
6461         expect(')');
6462
6463         return expression;
6464 }
6465
6466 /**
6467  * Parses a __builtin_va_copy() expression.
6468  */
6469 static expression_t *parse_va_copy(void)
6470 {
6471         expression_t *expression = allocate_expression_zero(EXPR_VA_COPY);
6472
6473         eat(T___builtin_va_copy);
6474
6475         add_anchor_token(')');
6476         add_anchor_token(',');
6477         expect('(');
6478         expression_t *dst = parse_assignment_expression();
6479         assign_error_t error = semantic_assign(type_valist, dst);
6480         report_assign_error(error, type_valist, dst, "call argument 1",
6481                             &dst->base.source_position);
6482         expression->va_copye.dst = dst;
6483
6484         rem_anchor_token(',');
6485         expect(',');
6486
6487         call_argument_t src;
6488         src.expression = parse_assignment_expression();
6489         check_call_argument(type_valist, &src, 2);
6490         expression->va_copye.src = src.expression;
6491         rem_anchor_token(')');
6492         expect(')');
6493
6494         return expression;
6495 }
6496
6497 /**
6498  * Parses a __builtin_constant_p() expression.
6499  */
6500 static expression_t *parse_builtin_constant(void)
6501 {
6502         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
6503
6504         eat(T___builtin_constant_p);
6505
6506         add_anchor_token(')');
6507         expect('(');
6508         expression->builtin_constant.value = parse_assignment_expression();
6509         rem_anchor_token(')');
6510         expect(')');
6511         expression->base.type = type_int;
6512
6513         return expression;
6514 }
6515
6516 /**
6517  * Parses a __builtin_types_compatible_p() expression.
6518  */
6519 static expression_t *parse_builtin_types_compatible(void)
6520 {
6521         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_TYPES_COMPATIBLE_P);
6522
6523         eat(T___builtin_types_compatible_p);
6524
6525         add_anchor_token(')');
6526         add_anchor_token(',');
6527         expect('(');
6528         expression->builtin_types_compatible.left = parse_typename();
6529         rem_anchor_token(',');
6530         expect(',');
6531         expression->builtin_types_compatible.right = parse_typename();
6532         rem_anchor_token(')');
6533         expect(')');
6534         expression->base.type = type_int;
6535
6536         return expression;
6537 }
6538
6539 /**
6540  * Parses a __builtin_is_*() compare expression.
6541  */
6542 static expression_t *parse_compare_builtin(void)
6543 {
6544         expression_kind_t kind;
6545         switch (token.kind) {
6546         case T___builtin_isgreater:      kind = EXPR_BINARY_ISGREATER;      break;
6547         case T___builtin_isgreaterequal: kind = EXPR_BINARY_ISGREATEREQUAL; break;
6548         case T___builtin_isless:         kind = EXPR_BINARY_ISLESS;         break;
6549         case T___builtin_islessequal:    kind = EXPR_BINARY_ISLESSEQUAL;    break;
6550         case T___builtin_islessgreater:  kind = EXPR_BINARY_ISLESSGREATER;  break;
6551         case T___builtin_isunordered:    kind = EXPR_BINARY_ISUNORDERED;    break;
6552         default: internal_errorf(HERE, "invalid compare builtin found");
6553         }
6554         expression_t *const expression = allocate_expression_zero(kind);
6555         next_token();
6556
6557         add_anchor_token(')');
6558         add_anchor_token(',');
6559         expect('(');
6560         expression->binary.left = parse_assignment_expression();
6561         rem_anchor_token(',');
6562         expect(',');
6563         expression->binary.right = parse_assignment_expression();
6564         rem_anchor_token(')');
6565         expect(')');
6566
6567         type_t *const orig_type_left  = expression->binary.left->base.type;
6568         type_t *const orig_type_right = expression->binary.right->base.type;
6569
6570         type_t *const type_left  = skip_typeref(orig_type_left);
6571         type_t *const type_right = skip_typeref(orig_type_right);
6572         if (!is_type_float(type_left) && !is_type_float(type_right)) {
6573                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
6574                         type_error_incompatible("invalid operands in comparison",
6575                                 &expression->base.source_position, orig_type_left, orig_type_right);
6576                 }
6577         } else {
6578                 semantic_comparison(&expression->binary);
6579         }
6580
6581         return expression;
6582 }
6583
6584 /**
6585  * Parses a MS assume() expression.
6586  */
6587 static expression_t *parse_assume(void)
6588 {
6589         expression_t *expression = allocate_expression_zero(EXPR_UNARY_ASSUME);
6590
6591         eat(T__assume);
6592
6593         add_anchor_token(')');
6594         expect('(');
6595         expression->unary.value = parse_assignment_expression();
6596         rem_anchor_token(')');
6597         expect(')');
6598
6599         expression->base.type = type_void;
6600         return expression;
6601 }
6602
6603 /**
6604  * Return the label for the current symbol or create a new one.
6605  */
6606 static label_t *get_label(char const *const context)
6607 {
6608         assert(current_function != NULL);
6609
6610         symbol_t *const sym = expect_identifier(context, NULL);
6611         if (!sym)
6612                 return NULL;
6613
6614         entity_t *label = get_entity(sym, NAMESPACE_LABEL);
6615         /* If we find a local label, we already created the declaration. */
6616         if (label != NULL && label->kind == ENTITY_LOCAL_LABEL) {
6617                 if (label->base.parent_scope != current_scope) {
6618                         assert(label->base.parent_scope->depth < current_scope->depth);
6619                         current_function->goto_to_outer = true;
6620                 }
6621         } else if (label == NULL || label->base.parent_scope != &current_function->parameters) {
6622                 /* There is no matching label in the same function, so create a new one. */
6623                 source_position_t const nowhere = { NULL, 0, 0, false };
6624                 label = allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym, &nowhere);
6625                 label_push(label);
6626         }
6627
6628         return &label->label;
6629 }
6630
6631 /**
6632  * Parses a GNU && label address expression.
6633  */
6634 static expression_t *parse_label_address(void)
6635 {
6636         source_position_t const source_position = *HERE;
6637         eat(T_ANDAND);
6638
6639         label_t *const label = get_label("while parsing label address");
6640         if (!label)
6641                 return create_error_expression();
6642
6643         label->used          = true;
6644         label->address_taken = true;
6645
6646         expression_t *expression = allocate_expression_zero(EXPR_LABEL_ADDRESS);
6647         expression->base.source_position = source_position;
6648
6649         /* label address is treated as a void pointer */
6650         expression->base.type           = type_void_ptr;
6651         expression->label_address.label = label;
6652         return expression;
6653 }
6654
6655 /**
6656  * Parse a microsoft __noop expression.
6657  */
6658 static expression_t *parse_noop_expression(void)
6659 {
6660         /* the result is a (int)0 */
6661         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_MS_NOOP);
6662         literal->base.type           = type_int;
6663         literal->literal.value.begin = "__noop";
6664         literal->literal.value.size  = 6;
6665
6666         eat(T___noop);
6667
6668         if (token.kind == '(') {
6669                 /* parse arguments */
6670                 eat('(');
6671                 add_anchor_token(')');
6672                 add_anchor_token(',');
6673
6674                 if (token.kind != ')') do {
6675                         (void)parse_assignment_expression();
6676                 } while (next_if(','));
6677
6678                 rem_anchor_token(',');
6679                 rem_anchor_token(')');
6680         }
6681         expect(')');
6682
6683         return literal;
6684 }
6685
6686 /**
6687  * Parses a primary expression.
6688  */
6689 static expression_t *parse_primary_expression(void)
6690 {
6691         switch (token.kind) {
6692         case T_false:                        return parse_boolean_literal(false);
6693         case T_true:                         return parse_boolean_literal(true);
6694         case T_INTEGER:
6695         case T_FLOATINGPOINT:                return parse_number_literal();
6696         case T_CHARACTER_CONSTANT:           return parse_character_constant();
6697         case T_WIDE_CHARACTER_CONSTANT:      return parse_wide_character_constant();
6698         case T_STRING_LITERAL:               return parse_string_literal();
6699         case T___FUNCTION__:
6700         case T___func__:                     return parse_function_keyword(FUNCNAME_FUNCTION);
6701         case T___PRETTY_FUNCTION__:          return parse_function_keyword(FUNCNAME_PRETTY_FUNCTION);
6702         case T___FUNCSIG__:                  return parse_function_keyword(FUNCNAME_FUNCSIG);
6703         case T___FUNCDNAME__:                return parse_function_keyword(FUNCNAME_FUNCDNAME);
6704         case T___builtin_offsetof:           return parse_offsetof();
6705         case T___builtin_va_start:           return parse_va_start();
6706         case T___builtin_va_arg:             return parse_va_arg();
6707         case T___builtin_va_copy:            return parse_va_copy();
6708         case T___builtin_isgreater:
6709         case T___builtin_isgreaterequal:
6710         case T___builtin_isless:
6711         case T___builtin_islessequal:
6712         case T___builtin_islessgreater:
6713         case T___builtin_isunordered:        return parse_compare_builtin();
6714         case T___builtin_constant_p:         return parse_builtin_constant();
6715         case T___builtin_types_compatible_p: return parse_builtin_types_compatible();
6716         case T__assume:                      return parse_assume();
6717         case T_ANDAND:
6718                 if (GNU_MODE)
6719                         return parse_label_address();
6720                 break;
6721
6722         case '(':                            return parse_parenthesized_expression();
6723         case T___noop:                       return parse_noop_expression();
6724
6725         /* Gracefully handle type names while parsing expressions. */
6726         case T_COLONCOLON:
6727                 return parse_reference();
6728         case T_IDENTIFIER:
6729                 if (!is_typedef_symbol(token.base.symbol)) {
6730                         return parse_reference();
6731                 }
6732                 /* FALLTHROUGH */
6733         DECLARATION_START {
6734                 source_position_t const  pos = *HERE;
6735                 declaration_specifiers_t specifiers;
6736                 parse_declaration_specifiers(&specifiers);
6737                 type_t const *const type = parse_abstract_declarator(specifiers.type);
6738                 errorf(&pos, "encountered type '%T' while parsing expression", type);
6739                 return create_error_expression();
6740         }
6741         }
6742
6743         errorf(HERE, "unexpected token %K, expected an expression", &token);
6744         eat_until_anchor();
6745         return create_error_expression();
6746 }
6747
6748 static expression_t *parse_array_expression(expression_t *left)
6749 {
6750         expression_t              *const expr = allocate_expression_zero(EXPR_ARRAY_ACCESS);
6751         array_access_expression_t *const arr  = &expr->array_access;
6752
6753         eat('[');
6754         add_anchor_token(']');
6755
6756         expression_t *const inside = parse_expression();
6757
6758         type_t *const orig_type_left   = left->base.type;
6759         type_t *const orig_type_inside = inside->base.type;
6760
6761         type_t *const type_left   = skip_typeref(orig_type_left);
6762         type_t *const type_inside = skip_typeref(orig_type_inside);
6763
6764         expression_t *ref;
6765         expression_t *idx;
6766         type_t       *idx_type;
6767         type_t       *res_type;
6768         if (is_type_pointer(type_left)) {
6769                 ref      = left;
6770                 idx      = inside;
6771                 idx_type = type_inside;
6772                 res_type = type_left->pointer.points_to;
6773                 goto check_idx;
6774         } else if (is_type_pointer(type_inside)) {
6775                 arr->flipped = true;
6776                 ref      = inside;
6777                 idx      = left;
6778                 idx_type = type_left;
6779                 res_type = type_inside->pointer.points_to;
6780 check_idx:
6781                 res_type = automatic_type_conversion(res_type);
6782                 if (!is_type_integer(idx_type)) {
6783                         errorf(&idx->base.source_position, "array subscript must have integer type");
6784                 } else if (is_type_atomic(idx_type, ATOMIC_TYPE_CHAR)) {
6785                         source_position_t const *const pos = &idx->base.source_position;
6786                         warningf(WARN_CHAR_SUBSCRIPTS, pos, "array subscript has char type");
6787                 }
6788         } else {
6789                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
6790                         errorf(&expr->base.source_position, "invalid types '%T[%T]' for array access", orig_type_left, orig_type_inside);
6791                 }
6792                 res_type = type_error_type;
6793                 ref      = left;
6794                 idx      = inside;
6795         }
6796
6797         arr->array_ref = ref;
6798         arr->index     = idx;
6799         arr->base.type = res_type;
6800
6801         rem_anchor_token(']');
6802         expect(']');
6803         return expr;
6804 }
6805
6806 static bool is_bitfield(const expression_t *expression)
6807 {
6808         return expression->kind == EXPR_SELECT
6809                 && expression->select.compound_entry->compound_member.bitfield;
6810 }
6811
6812 static expression_t *parse_typeprop(expression_kind_t const kind)
6813 {
6814         expression_t  *tp_expression = allocate_expression_zero(kind);
6815         tp_expression->base.type     = type_size_t;
6816
6817         eat(kind == EXPR_SIZEOF ? T_sizeof : T___alignof__);
6818
6819         type_t       *orig_type;
6820         expression_t *expression;
6821         if (token.kind == '(' && is_declaration_specifier(look_ahead(1))) {
6822                 source_position_t const pos = *HERE;
6823                 eat('(');
6824                 add_anchor_token(')');
6825                 orig_type = parse_typename();
6826                 rem_anchor_token(')');
6827                 expect(')');
6828
6829                 if (token.kind == '{') {
6830                         /* It was not sizeof(type) after all.  It is sizeof of an expression
6831                          * starting with a compound literal */
6832                         expression = parse_compound_literal(&pos, orig_type);
6833                         goto typeprop_expression;
6834                 }
6835         } else {
6836                 expression = parse_subexpression(PREC_UNARY);
6837
6838 typeprop_expression:
6839                 if (is_bitfield(expression)) {
6840                         char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6841                         errorf(&tp_expression->base.source_position,
6842                                    "operand of %s expression must not be a bitfield", what);
6843                 }
6844
6845                 tp_expression->typeprop.tp_expression = expression;
6846
6847                 orig_type = revert_automatic_type_conversion(expression);
6848                 expression->base.type = orig_type;
6849         }
6850
6851         tp_expression->typeprop.type   = orig_type;
6852         type_t const* const type       = skip_typeref(orig_type);
6853         char   const*       wrong_type = NULL;
6854         if (is_type_incomplete(type)) {
6855                 if (!is_type_void(type) || !GNU_MODE)
6856                         wrong_type = "incomplete";
6857         } else if (type->kind == TYPE_FUNCTION) {
6858                 if (GNU_MODE) {
6859                         /* function types are allowed (and return 1) */
6860                         source_position_t const *const pos  = &tp_expression->base.source_position;
6861                         char              const *const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6862                         warningf(WARN_OTHER, pos, "%s expression with function argument returns invalid result", what);
6863                 } else {
6864                         wrong_type = "function";
6865                 }
6866         }
6867
6868         if (wrong_type != NULL) {
6869                 char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6870                 errorf(&tp_expression->base.source_position,
6871                                 "operand of %s expression must not be of %s type '%T'",
6872                                 what, wrong_type, orig_type);
6873         }
6874
6875         return tp_expression;
6876 }
6877
6878 static expression_t *parse_sizeof(void)
6879 {
6880         return parse_typeprop(EXPR_SIZEOF);
6881 }
6882
6883 static expression_t *parse_alignof(void)
6884 {
6885         return parse_typeprop(EXPR_ALIGNOF);
6886 }
6887
6888 static expression_t *parse_select_expression(expression_t *addr)
6889 {
6890         assert(token.kind == '.' || token.kind == T_MINUSGREATER);
6891         bool select_left_arrow = (token.kind == T_MINUSGREATER);
6892         source_position_t const pos = *HERE;
6893         next_token();
6894
6895         symbol_t *const symbol = expect_identifier("while parsing select", NULL);
6896         if (!symbol)
6897                 return create_error_expression();
6898
6899         type_t *const orig_type = addr->base.type;
6900         type_t *const type      = skip_typeref(orig_type);
6901
6902         type_t *type_left;
6903         bool    saw_error = false;
6904         if (is_type_pointer(type)) {
6905                 if (!select_left_arrow) {
6906                         errorf(&pos,
6907                                "request for member '%Y' in something not a struct or union, but '%T'",
6908                                symbol, orig_type);
6909                         saw_error = true;
6910                 }
6911                 type_left = skip_typeref(type->pointer.points_to);
6912         } else {
6913                 if (select_left_arrow && is_type_valid(type)) {
6914                         errorf(&pos, "left hand side of '->' is not a pointer, but '%T'", orig_type);
6915                         saw_error = true;
6916                 }
6917                 type_left = type;
6918         }
6919
6920         if (type_left->kind != TYPE_COMPOUND_STRUCT &&
6921             type_left->kind != TYPE_COMPOUND_UNION) {
6922
6923                 if (is_type_valid(type_left) && !saw_error) {
6924                         errorf(&pos,
6925                                "request for member '%Y' in something not a struct or union, but '%T'",
6926                                symbol, type_left);
6927                 }
6928                 return create_error_expression();
6929         }
6930
6931         compound_t *compound = type_left->compound.compound;
6932         if (!compound->complete) {
6933                 errorf(&pos, "request for member '%Y' in incomplete type '%T'",
6934                        symbol, type_left);
6935                 return create_error_expression();
6936         }
6937
6938         type_qualifiers_t  qualifiers = type_left->base.qualifiers;
6939         expression_t      *result     =
6940                 find_create_select(&pos, addr, qualifiers, compound, symbol);
6941
6942         if (result == NULL) {
6943                 errorf(&pos, "'%T' has no member named '%Y'", orig_type, symbol);
6944                 return create_error_expression();
6945         }
6946
6947         return result;
6948 }
6949
6950 static void check_call_argument(type_t          *expected_type,
6951                                 call_argument_t *argument, unsigned pos)
6952 {
6953         type_t         *expected_type_skip = skip_typeref(expected_type);
6954         assign_error_t  error              = ASSIGN_ERROR_INCOMPATIBLE;
6955         expression_t   *arg_expr           = argument->expression;
6956         type_t         *arg_type           = skip_typeref(arg_expr->base.type);
6957
6958         /* handle transparent union gnu extension */
6959         if (is_type_union(expected_type_skip)
6960                         && (get_type_modifiers(expected_type) & DM_TRANSPARENT_UNION)) {
6961                 compound_t *union_decl  = expected_type_skip->compound.compound;
6962                 type_t     *best_type   = NULL;
6963                 entity_t   *entry       = union_decl->members.entities;
6964                 for ( ; entry != NULL; entry = entry->base.next) {
6965                         assert(is_declaration(entry));
6966                         type_t *decl_type = entry->declaration.type;
6967                         error = semantic_assign(decl_type, arg_expr);
6968                         if (error == ASSIGN_ERROR_INCOMPATIBLE
6969                                 || error == ASSIGN_ERROR_POINTER_QUALIFIER_MISSING)
6970                                 continue;
6971
6972                         if (error == ASSIGN_SUCCESS) {
6973                                 best_type = decl_type;
6974                         } else if (best_type == NULL) {
6975                                 best_type = decl_type;
6976                         }
6977                 }
6978
6979                 if (best_type != NULL) {
6980                         expected_type = best_type;
6981                 }
6982         }
6983
6984         error                = semantic_assign(expected_type, arg_expr);
6985         argument->expression = create_implicit_cast(arg_expr, expected_type);
6986
6987         if (error != ASSIGN_SUCCESS) {
6988                 /* report exact scope in error messages (like "in argument 3") */
6989                 char buf[64];
6990                 snprintf(buf, sizeof(buf), "call argument %u", pos);
6991                 report_assign_error(error, expected_type, arg_expr, buf,
6992                                     &arg_expr->base.source_position);
6993         } else {
6994                 type_t *const promoted_type = get_default_promoted_type(arg_type);
6995                 if (!types_compatible(expected_type_skip, promoted_type) &&
6996                     !types_compatible(expected_type_skip, type_void_ptr) &&
6997                     !types_compatible(type_void_ptr,      promoted_type)) {
6998                         /* Deliberately show the skipped types in this warning */
6999                         source_position_t const *const apos = &arg_expr->base.source_position;
7000                         warningf(WARN_TRADITIONAL, apos, "passing call argument %u as '%T' rather than '%T' due to prototype", pos, expected_type_skip, promoted_type);
7001                 }
7002         }
7003 }
7004
7005 /**
7006  * Handle the semantic restrictions of builtin calls
7007  */
7008 static void handle_builtin_argument_restrictions(call_expression_t *call)
7009 {
7010         entity_t *entity = call->function->reference.entity;
7011         switch (entity->function.btk) {
7012         case BUILTIN_FIRM:
7013                 switch (entity->function.b.firm_builtin_kind) {
7014                 case ir_bk_return_address:
7015                 case ir_bk_frame_address: {
7016                         /* argument must be constant */
7017                         call_argument_t *argument = call->arguments;
7018
7019                         if (is_constant_expression(argument->expression) == EXPR_CLASS_VARIABLE) {
7020                                 errorf(&call->base.source_position,
7021                                            "argument of '%Y' must be a constant expression",
7022                                            call->function->reference.entity->base.symbol);
7023                         }
7024                         break;
7025                 }
7026                 case ir_bk_prefetch:
7027                         /* second and third argument must be constant if existent */
7028                         if (call->arguments == NULL)
7029                                 break;
7030                         call_argument_t *rw = call->arguments->next;
7031                         call_argument_t *locality = NULL;
7032
7033                         if (rw != NULL) {
7034                                 if (is_constant_expression(rw->expression) == EXPR_CLASS_VARIABLE) {
7035                                         errorf(&call->base.source_position,
7036                                                    "second argument of '%Y' must be a constant expression",
7037                                                    call->function->reference.entity->base.symbol);
7038                                 }
7039                                 locality = rw->next;
7040                         }
7041                         if (locality != NULL) {
7042                                 if (is_constant_expression(locality->expression) == EXPR_CLASS_VARIABLE) {
7043                                         errorf(&call->base.source_position,
7044                                                    "third argument of '%Y' must be a constant expression",
7045                                                    call->function->reference.entity->base.symbol);
7046                                 }
7047                                 locality = rw->next;
7048                         }
7049                         break;
7050                 default:
7051                         break;
7052                 }
7053
7054         case BUILTIN_OBJECT_SIZE:
7055                 if (call->arguments == NULL)
7056                         break;
7057
7058                 call_argument_t *arg = call->arguments->next;
7059                 if (arg != NULL && is_constant_expression(arg->expression) == EXPR_CLASS_VARIABLE) {
7060                         errorf(&call->base.source_position,
7061                                    "second argument of '%Y' must be a constant expression",
7062                                    call->function->reference.entity->base.symbol);
7063                 }
7064                 break;
7065         default:
7066                 break;
7067         }
7068 }
7069
7070 /**
7071  * Parse a call expression, ie. expression '( ... )'.
7072  *
7073  * @param expression  the function address
7074  */
7075 static expression_t *parse_call_expression(expression_t *expression)
7076 {
7077         expression_t      *result = allocate_expression_zero(EXPR_CALL);
7078         call_expression_t *call   = &result->call;
7079         call->function            = expression;
7080
7081         type_t *const orig_type = expression->base.type;
7082         type_t *const type      = skip_typeref(orig_type);
7083
7084         function_type_t *function_type = NULL;
7085         if (is_type_pointer(type)) {
7086                 type_t *const to_type = skip_typeref(type->pointer.points_to);
7087
7088                 if (is_type_function(to_type)) {
7089                         function_type   = &to_type->function;
7090                         call->base.type = function_type->return_type;
7091                 }
7092         }
7093
7094         if (function_type == NULL && is_type_valid(type)) {
7095                 errorf(HERE,
7096                        "called object '%E' (type '%T') is not a pointer to a function",
7097                        expression, orig_type);
7098         }
7099
7100         /* parse arguments */
7101         eat('(');
7102         add_anchor_token(')');
7103         add_anchor_token(',');
7104
7105         if (token.kind != ')') {
7106                 call_argument_t **anchor = &call->arguments;
7107                 do {
7108                         call_argument_t *argument = allocate_ast_zero(sizeof(*argument));
7109                         argument->expression = parse_assignment_expression();
7110
7111                         *anchor = argument;
7112                         anchor  = &argument->next;
7113                 } while (next_if(','));
7114         }
7115         rem_anchor_token(',');
7116         rem_anchor_token(')');
7117         expect(')');
7118
7119         if (function_type == NULL)
7120                 return result;
7121
7122         /* check type and count of call arguments */
7123         function_parameter_t *parameter = function_type->parameters;
7124         call_argument_t      *argument  = call->arguments;
7125         if (!function_type->unspecified_parameters) {
7126                 for (unsigned pos = 0; parameter != NULL && argument != NULL;
7127                                 parameter = parameter->next, argument = argument->next) {
7128                         check_call_argument(parameter->type, argument, ++pos);
7129                 }
7130
7131                 if (parameter != NULL) {
7132                         errorf(&expression->base.source_position, "too few arguments to function '%E'", expression);
7133                 } else if (argument != NULL && !function_type->variadic) {
7134                         errorf(&argument->expression->base.source_position, "too many arguments to function '%E'", expression);
7135                 }
7136         }
7137
7138         /* do default promotion for other arguments */
7139         for (; argument != NULL; argument = argument->next) {
7140                 type_t *argument_type = argument->expression->base.type;
7141                 if (!is_type_object(skip_typeref(argument_type))) {
7142                         errorf(&argument->expression->base.source_position,
7143                                "call argument '%E' must not be void", argument->expression);
7144                 }
7145
7146                 argument_type = get_default_promoted_type(argument_type);
7147
7148                 argument->expression
7149                         = create_implicit_cast(argument->expression, argument_type);
7150         }
7151
7152         check_format(call);
7153
7154         if (is_type_compound(skip_typeref(function_type->return_type))) {
7155                 source_position_t const *const pos = &expression->base.source_position;
7156                 warningf(WARN_AGGREGATE_RETURN, pos, "function call has aggregate value");
7157         }
7158
7159         if (expression->kind == EXPR_REFERENCE) {
7160                 reference_expression_t *reference = &expression->reference;
7161                 if (reference->entity->kind == ENTITY_FUNCTION &&
7162                     reference->entity->function.btk != BUILTIN_NONE)
7163                         handle_builtin_argument_restrictions(call);
7164         }
7165
7166         return result;
7167 }
7168
7169 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
7170
7171 static bool same_compound_type(const type_t *type1, const type_t *type2)
7172 {
7173         return
7174                 is_type_compound(type1) &&
7175                 type1->kind == type2->kind &&
7176                 type1->compound.compound == type2->compound.compound;
7177 }
7178
7179 static expression_t const *get_reference_address(expression_t const *expr)
7180 {
7181         bool regular_take_address = true;
7182         for (;;) {
7183                 if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7184                         expr = expr->unary.value;
7185                 } else {
7186                         regular_take_address = false;
7187                 }
7188
7189                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7190                         break;
7191
7192                 expr = expr->unary.value;
7193         }
7194
7195         if (expr->kind != EXPR_REFERENCE)
7196                 return NULL;
7197
7198         /* special case for functions which are automatically converted to a
7199          * pointer to function without an extra TAKE_ADDRESS operation */
7200         if (!regular_take_address &&
7201                         expr->reference.entity->kind != ENTITY_FUNCTION) {
7202                 return NULL;
7203         }
7204
7205         return expr;
7206 }
7207
7208 static void warn_reference_address_as_bool(expression_t const* expr)
7209 {
7210         expr = get_reference_address(expr);
7211         if (expr != NULL) {
7212                 source_position_t const *const pos = &expr->base.source_position;
7213                 entity_t          const *const ent = expr->reference.entity;
7214                 warningf(WARN_ADDRESS, pos, "the address of '%N' will always evaluate as 'true'", ent);
7215         }
7216 }
7217
7218 static void warn_assignment_in_condition(const expression_t *const expr)
7219 {
7220         if (expr->base.kind != EXPR_BINARY_ASSIGN)
7221                 return;
7222         if (expr->base.parenthesized)
7223                 return;
7224         source_position_t const *const pos = &expr->base.source_position;
7225         warningf(WARN_PARENTHESES, pos, "suggest parentheses around assignment used as truth value");
7226 }
7227
7228 static void semantic_condition(expression_t const *const expr,
7229                                char const *const context)
7230 {
7231         type_t *const type = skip_typeref(expr->base.type);
7232         if (is_type_scalar(type)) {
7233                 warn_reference_address_as_bool(expr);
7234                 warn_assignment_in_condition(expr);
7235         } else if (is_type_valid(type)) {
7236                 errorf(&expr->base.source_position,
7237                                 "%s must have scalar type", context);
7238         }
7239 }
7240
7241 /**
7242  * Parse a conditional expression, ie. 'expression ? ... : ...'.
7243  *
7244  * @param expression  the conditional expression
7245  */
7246 static expression_t *parse_conditional_expression(expression_t *expression)
7247 {
7248         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
7249
7250         conditional_expression_t *conditional = &result->conditional;
7251         conditional->condition                = expression;
7252
7253         eat('?');
7254         add_anchor_token(':');
7255
7256         /* §6.5.15:2  The first operand shall have scalar type. */
7257         semantic_condition(expression, "condition of conditional operator");
7258
7259         expression_t *true_expression = expression;
7260         bool          gnu_cond = false;
7261         if (GNU_MODE && token.kind == ':') {
7262                 gnu_cond = true;
7263         } else {
7264                 true_expression = parse_expression();
7265         }
7266         rem_anchor_token(':');
7267         expect(':');
7268         expression_t *false_expression =
7269                 parse_subexpression(c_mode & _CXX ? PREC_ASSIGNMENT : PREC_CONDITIONAL);
7270
7271         type_t *const orig_true_type  = true_expression->base.type;
7272         type_t *const orig_false_type = false_expression->base.type;
7273         type_t *const true_type       = skip_typeref(orig_true_type);
7274         type_t *const false_type      = skip_typeref(orig_false_type);
7275
7276         /* 6.5.15.3 */
7277         source_position_t const *const pos = &conditional->base.source_position;
7278         type_t                        *result_type;
7279         if (is_type_void(true_type) || is_type_void(false_type)) {
7280                 /* ISO/IEC 14882:1998(E) §5.16:2 */
7281                 if (true_expression->kind == EXPR_UNARY_THROW) {
7282                         result_type = false_type;
7283                 } else if (false_expression->kind == EXPR_UNARY_THROW) {
7284                         result_type = true_type;
7285                 } else {
7286                         if (!is_type_void(true_type) || !is_type_void(false_type)) {
7287                                 warningf(WARN_OTHER, pos, "ISO C forbids conditional expression with only one void side");
7288                         }
7289                         result_type = type_void;
7290                 }
7291         } else if (is_type_arithmetic(true_type)
7292                    && is_type_arithmetic(false_type)) {
7293                 result_type = semantic_arithmetic(true_type, false_type);
7294         } else if (same_compound_type(true_type, false_type)) {
7295                 /* just take 1 of the 2 types */
7296                 result_type = true_type;
7297         } else if (is_type_pointer(true_type) || is_type_pointer(false_type)) {
7298                 type_t *pointer_type;
7299                 type_t *other_type;
7300                 expression_t *other_expression;
7301                 if (is_type_pointer(true_type) &&
7302                                 (!is_type_pointer(false_type) || is_null_pointer_constant(false_expression))) {
7303                         pointer_type     = true_type;
7304                         other_type       = false_type;
7305                         other_expression = false_expression;
7306                 } else {
7307                         pointer_type     = false_type;
7308                         other_type       = true_type;
7309                         other_expression = true_expression;
7310                 }
7311
7312                 if (is_null_pointer_constant(other_expression)) {
7313                         result_type = pointer_type;
7314                 } else if (is_type_pointer(other_type)) {
7315                         type_t *to1 = skip_typeref(pointer_type->pointer.points_to);
7316                         type_t *to2 = skip_typeref(other_type->pointer.points_to);
7317
7318                         type_t *to;
7319                         if (is_type_void(to1) || is_type_void(to2)) {
7320                                 to = type_void;
7321                         } else if (types_compatible(get_unqualified_type(to1),
7322                                                     get_unqualified_type(to2))) {
7323                                 to = to1;
7324                         } else {
7325                                 warningf(WARN_OTHER, pos, "pointer types '%T' and '%T' in conditional expression are incompatible", true_type, false_type);
7326                                 to = type_void;
7327                         }
7328
7329                         type_t *const type =
7330                                 get_qualified_type(to, to1->base.qualifiers | to2->base.qualifiers);
7331                         result_type = make_pointer_type(type, TYPE_QUALIFIER_NONE);
7332                 } else if (is_type_integer(other_type)) {
7333                         warningf(WARN_OTHER, pos, "pointer/integer type mismatch in conditional expression ('%T' and '%T')", true_type, false_type);
7334                         result_type = pointer_type;
7335                 } else {
7336                         goto types_incompatible;
7337                 }
7338         } else {
7339 types_incompatible:
7340                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
7341                         type_error_incompatible("while parsing conditional", pos, true_type, false_type);
7342                 }
7343                 result_type = type_error_type;
7344         }
7345
7346         conditional->true_expression
7347                 = gnu_cond ? NULL : create_implicit_cast(true_expression, result_type);
7348         conditional->false_expression
7349                 = create_implicit_cast(false_expression, result_type);
7350         conditional->base.type = result_type;
7351         return result;
7352 }
7353
7354 /**
7355  * Parse an extension expression.
7356  */
7357 static expression_t *parse_extension(void)
7358 {
7359         PUSH_EXTENSION();
7360         expression_t *expression = parse_subexpression(PREC_UNARY);
7361         POP_EXTENSION();
7362         return expression;
7363 }
7364
7365 /**
7366  * Parse a __builtin_classify_type() expression.
7367  */
7368 static expression_t *parse_builtin_classify_type(void)
7369 {
7370         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
7371         result->base.type    = type_int;
7372
7373         eat(T___builtin_classify_type);
7374
7375         add_anchor_token(')');
7376         expect('(');
7377         expression_t *expression = parse_expression();
7378         rem_anchor_token(')');
7379         expect(')');
7380         result->classify_type.type_expression = expression;
7381
7382         return result;
7383 }
7384
7385 /**
7386  * Parse a delete expression
7387  * ISO/IEC 14882:1998(E) §5.3.5
7388  */
7389 static expression_t *parse_delete(void)
7390 {
7391         expression_t *const result = allocate_expression_zero(EXPR_UNARY_DELETE);
7392         result->base.type          = type_void;
7393
7394         eat(T_delete);
7395
7396         if (next_if('[')) {
7397                 result->kind = EXPR_UNARY_DELETE_ARRAY;
7398                 expect(']');
7399         }
7400
7401         expression_t *const value = parse_subexpression(PREC_CAST);
7402         result->unary.value = value;
7403
7404         type_t *const type = skip_typeref(value->base.type);
7405         if (!is_type_pointer(type)) {
7406                 if (is_type_valid(type)) {
7407                         errorf(&value->base.source_position,
7408                                         "operand of delete must have pointer type");
7409                 }
7410         } else if (is_type_void(skip_typeref(type->pointer.points_to))) {
7411                 source_position_t const *const pos = &value->base.source_position;
7412                 warningf(WARN_OTHER, pos, "deleting 'void*' is undefined");
7413         }
7414
7415         return result;
7416 }
7417
7418 /**
7419  * Parse a throw expression
7420  * ISO/IEC 14882:1998(E) §15:1
7421  */
7422 static expression_t *parse_throw(void)
7423 {
7424         expression_t *const result = allocate_expression_zero(EXPR_UNARY_THROW);
7425         result->base.type          = type_void;
7426
7427         eat(T_throw);
7428
7429         expression_t *value = NULL;
7430         switch (token.kind) {
7431                 EXPRESSION_START {
7432                         value = parse_assignment_expression();
7433                         /* ISO/IEC 14882:1998(E) §15.1:3 */
7434                         type_t *const orig_type = value->base.type;
7435                         type_t *const type      = skip_typeref(orig_type);
7436                         if (is_type_incomplete(type)) {
7437                                 errorf(&value->base.source_position,
7438                                                 "cannot throw object of incomplete type '%T'", orig_type);
7439                         } else if (is_type_pointer(type)) {
7440                                 type_t *const points_to = skip_typeref(type->pointer.points_to);
7441                                 if (is_type_incomplete(points_to) && !is_type_void(points_to)) {
7442                                         errorf(&value->base.source_position,
7443                                                         "cannot throw pointer to incomplete type '%T'", orig_type);
7444                                 }
7445                         }
7446                 }
7447
7448                 default:
7449                         break;
7450         }
7451         result->unary.value = value;
7452
7453         return result;
7454 }
7455
7456 static bool check_pointer_arithmetic(const source_position_t *source_position,
7457                                      type_t *pointer_type,
7458                                      type_t *orig_pointer_type)
7459 {
7460         type_t *points_to = pointer_type->pointer.points_to;
7461         points_to = skip_typeref(points_to);
7462
7463         if (is_type_incomplete(points_to)) {
7464                 if (!GNU_MODE || !is_type_void(points_to)) {
7465                         errorf(source_position,
7466                                "arithmetic with pointer to incomplete type '%T' not allowed",
7467                                orig_pointer_type);
7468                         return false;
7469                 } else {
7470                         warningf(WARN_POINTER_ARITH, source_position, "pointer of type '%T' used in arithmetic", orig_pointer_type);
7471                 }
7472         } else if (is_type_function(points_to)) {
7473                 if (!GNU_MODE) {
7474                         errorf(source_position,
7475                                "arithmetic with pointer to function type '%T' not allowed",
7476                                orig_pointer_type);
7477                         return false;
7478                 } else {
7479                         warningf(WARN_POINTER_ARITH, source_position, "pointer to a function '%T' used in arithmetic", orig_pointer_type);
7480                 }
7481         }
7482         return true;
7483 }
7484
7485 static bool is_lvalue(const expression_t *expression)
7486 {
7487         /* TODO: doesn't seem to be consistent with §6.3.2.1:1 */
7488         switch (expression->kind) {
7489         case EXPR_ARRAY_ACCESS:
7490         case EXPR_COMPOUND_LITERAL:
7491         case EXPR_REFERENCE:
7492         case EXPR_SELECT:
7493         case EXPR_UNARY_DEREFERENCE:
7494                 return true;
7495
7496         default: {
7497                 type_t *type = skip_typeref(expression->base.type);
7498                 return
7499                         /* ISO/IEC 14882:1998(E) §3.10:3 */
7500                         is_type_reference(type) ||
7501                         /* Claim it is an lvalue, if the type is invalid.  There was a parse
7502                          * error before, which maybe prevented properly recognizing it as
7503                          * lvalue. */
7504                         !is_type_valid(type);
7505         }
7506         }
7507 }
7508
7509 static void semantic_incdec(unary_expression_t *expression)
7510 {
7511         type_t *const orig_type = expression->value->base.type;
7512         type_t *const type      = skip_typeref(orig_type);
7513         if (is_type_pointer(type)) {
7514                 if (!check_pointer_arithmetic(&expression->base.source_position,
7515                                               type, orig_type)) {
7516                         return;
7517                 }
7518         } else if (!is_type_real(type) && is_type_valid(type)) {
7519                 /* TODO: improve error message */
7520                 errorf(&expression->base.source_position,
7521                        "operation needs an arithmetic or pointer type");
7522                 return;
7523         }
7524         if (!is_lvalue(expression->value)) {
7525                 /* TODO: improve error message */
7526                 errorf(&expression->base.source_position, "lvalue required as operand");
7527         }
7528         expression->base.type = orig_type;
7529 }
7530
7531 static void promote_unary_int_expr(unary_expression_t *const expr, type_t *const type)
7532 {
7533         type_t *const res_type = promote_integer(type);
7534         expr->base.type = res_type;
7535         expr->value     = create_implicit_cast(expr->value, res_type);
7536 }
7537
7538 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
7539 {
7540         type_t *const orig_type = expression->value->base.type;
7541         type_t *const type      = skip_typeref(orig_type);
7542         if (!is_type_arithmetic(type)) {
7543                 if (is_type_valid(type)) {
7544                         /* TODO: improve error message */
7545                         errorf(&expression->base.source_position,
7546                                 "operation needs an arithmetic type");
7547                 }
7548                 return;
7549         } else if (is_type_integer(type)) {
7550                 promote_unary_int_expr(expression, type);
7551         } else {
7552                 expression->base.type = orig_type;
7553         }
7554 }
7555
7556 static void semantic_unexpr_plus(unary_expression_t *expression)
7557 {
7558         semantic_unexpr_arithmetic(expression);
7559         source_position_t const *const pos = &expression->base.source_position;
7560         warningf(WARN_TRADITIONAL, pos, "traditional C rejects the unary plus operator");
7561 }
7562
7563 static void semantic_not(unary_expression_t *expression)
7564 {
7565         /* §6.5.3.3:1  The operand [...] of the ! operator, scalar type. */
7566         semantic_condition(expression->value, "operand of !");
7567         expression->base.type = c_mode & _CXX ? type_bool : type_int;
7568 }
7569
7570 static void semantic_unexpr_integer(unary_expression_t *expression)
7571 {
7572         type_t *const orig_type = expression->value->base.type;
7573         type_t *const type      = skip_typeref(orig_type);
7574         if (!is_type_integer(type)) {
7575                 if (is_type_valid(type)) {
7576                         errorf(&expression->base.source_position,
7577                                "operand of ~ must be of integer type");
7578                 }
7579                 return;
7580         }
7581
7582         promote_unary_int_expr(expression, type);
7583 }
7584
7585 static void semantic_dereference(unary_expression_t *expression)
7586 {
7587         type_t *const orig_type = expression->value->base.type;
7588         type_t *const type      = skip_typeref(orig_type);
7589         if (!is_type_pointer(type)) {
7590                 if (is_type_valid(type)) {
7591                         errorf(&expression->base.source_position,
7592                                "Unary '*' needs pointer or array type, but type '%T' given", orig_type);
7593                 }
7594                 return;
7595         }
7596
7597         type_t *result_type   = type->pointer.points_to;
7598         result_type           = automatic_type_conversion(result_type);
7599         expression->base.type = result_type;
7600 }
7601
7602 /**
7603  * Record that an address is taken (expression represents an lvalue).
7604  *
7605  * @param expression       the expression
7606  * @param may_be_register  if true, the expression might be an register
7607  */
7608 static void set_address_taken(expression_t *expression, bool may_be_register)
7609 {
7610         if (expression->kind != EXPR_REFERENCE)
7611                 return;
7612
7613         entity_t *const entity = expression->reference.entity;
7614
7615         if (entity->kind != ENTITY_VARIABLE && entity->kind != ENTITY_PARAMETER)
7616                 return;
7617
7618         if (entity->declaration.storage_class == STORAGE_CLASS_REGISTER
7619                         && !may_be_register) {
7620                 source_position_t const *const pos = &expression->base.source_position;
7621                 errorf(pos, "address of register '%N' requested", entity);
7622         }
7623
7624         entity->variable.address_taken = true;
7625 }
7626
7627 /**
7628  * Check the semantic of the address taken expression.
7629  */
7630 static void semantic_take_addr(unary_expression_t *expression)
7631 {
7632         expression_t *value = expression->value;
7633         value->base.type    = revert_automatic_type_conversion(value);
7634
7635         type_t *orig_type = value->base.type;
7636         type_t *type      = skip_typeref(orig_type);
7637         if (!is_type_valid(type))
7638                 return;
7639
7640         /* §6.5.3.2 */
7641         if (!is_lvalue(value)) {
7642                 errorf(&expression->base.source_position, "'&' requires an lvalue");
7643         }
7644         if (is_bitfield(value)) {
7645                 errorf(&expression->base.source_position,
7646                        "'&' not allowed on bitfield");
7647         }
7648
7649         set_address_taken(value, false);
7650
7651         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
7652 }
7653
7654 #define CREATE_UNARY_EXPRESSION_PARSER(token_kind, unexpression_type, sfunc) \
7655 static expression_t *parse_##unexpression_type(void)                         \
7656 {                                                                            \
7657         expression_t *unary_expression                                           \
7658                 = allocate_expression_zero(unexpression_type);                       \
7659         eat(token_kind);                                                         \
7660         unary_expression->unary.value = parse_subexpression(PREC_UNARY);         \
7661                                                                                  \
7662         sfunc(&unary_expression->unary);                                         \
7663                                                                                  \
7664         return unary_expression;                                                 \
7665 }
7666
7667 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
7668                                semantic_unexpr_arithmetic)
7669 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
7670                                semantic_unexpr_plus)
7671 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
7672                                semantic_not)
7673 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
7674                                semantic_dereference)
7675 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
7676                                semantic_take_addr)
7677 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
7678                                semantic_unexpr_integer)
7679 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
7680                                semantic_incdec)
7681 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
7682                                semantic_incdec)
7683
7684 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_kind, unexpression_type, \
7685                                                sfunc)                         \
7686 static expression_t *parse_##unexpression_type(expression_t *left)            \
7687 {                                                                             \
7688         expression_t *unary_expression                                            \
7689                 = allocate_expression_zero(unexpression_type);                        \
7690         eat(token_kind);                                                          \
7691         unary_expression->unary.value = left;                                     \
7692                                                                                   \
7693         sfunc(&unary_expression->unary);                                          \
7694                                                                               \
7695         return unary_expression;                                                  \
7696 }
7697
7698 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
7699                                        EXPR_UNARY_POSTFIX_INCREMENT,
7700                                        semantic_incdec)
7701 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
7702                                        EXPR_UNARY_POSTFIX_DECREMENT,
7703                                        semantic_incdec)
7704
7705 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
7706 {
7707         /* TODO: handle complex + imaginary types */
7708
7709         type_left  = get_unqualified_type(type_left);
7710         type_right = get_unqualified_type(type_right);
7711
7712         /* §6.3.1.8 Usual arithmetic conversions */
7713         if (type_left == type_long_double || type_right == type_long_double) {
7714                 return type_long_double;
7715         } else if (type_left == type_double || type_right == type_double) {
7716                 return type_double;
7717         } else if (type_left == type_float || type_right == type_float) {
7718                 return type_float;
7719         }
7720
7721         type_left  = promote_integer(type_left);
7722         type_right = promote_integer(type_right);
7723
7724         if (type_left == type_right)
7725                 return type_left;
7726
7727         bool     const signed_left  = is_type_signed(type_left);
7728         bool     const signed_right = is_type_signed(type_right);
7729         unsigned const rank_left    = get_akind_rank(get_akind(type_left));
7730         unsigned const rank_right   = get_akind_rank(get_akind(type_right));
7731
7732         if (signed_left == signed_right)
7733                 return rank_left >= rank_right ? type_left : type_right;
7734
7735         unsigned           s_rank;
7736         unsigned           u_rank;
7737         atomic_type_kind_t s_akind;
7738         atomic_type_kind_t u_akind;
7739         type_t *s_type;
7740         type_t *u_type;
7741         if (signed_left) {
7742                 s_type = type_left;
7743                 u_type = type_right;
7744         } else {
7745                 s_type = type_right;
7746                 u_type = type_left;
7747         }
7748         s_akind = get_akind(s_type);
7749         u_akind = get_akind(u_type);
7750         s_rank  = get_akind_rank(s_akind);
7751         u_rank  = get_akind_rank(u_akind);
7752
7753         if (u_rank >= s_rank)
7754                 return u_type;
7755
7756         if (get_atomic_type_size(s_akind) > get_atomic_type_size(u_akind))
7757                 return s_type;
7758
7759         switch (s_akind) {
7760         case ATOMIC_TYPE_INT:      return type_unsigned_int;
7761         case ATOMIC_TYPE_LONG:     return type_unsigned_long;
7762         case ATOMIC_TYPE_LONGLONG: return type_unsigned_long_long;
7763
7764         default: panic("invalid atomic type");
7765         }
7766 }
7767
7768 /**
7769  * Check the semantic restrictions for a binary expression.
7770  */
7771 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
7772 {
7773         expression_t *const left            = expression->left;
7774         expression_t *const right           = expression->right;
7775         type_t       *const orig_type_left  = left->base.type;
7776         type_t       *const orig_type_right = right->base.type;
7777         type_t       *const type_left       = skip_typeref(orig_type_left);
7778         type_t       *const type_right      = skip_typeref(orig_type_right);
7779
7780         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
7781                 /* TODO: improve error message */
7782                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7783                         errorf(&expression->base.source_position,
7784                                "operation needs arithmetic types");
7785                 }
7786                 return;
7787         }
7788
7789         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7790         expression->left      = create_implicit_cast(left, arithmetic_type);
7791         expression->right     = create_implicit_cast(right, arithmetic_type);
7792         expression->base.type = arithmetic_type;
7793 }
7794
7795 static void semantic_binexpr_integer(binary_expression_t *const 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_integer(type_left) || !is_type_integer(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 integer types");
7809                 }
7810                 return;
7811         }
7812
7813         type_t *const result_type = semantic_arithmetic(type_left, type_right);
7814         expression->left      = create_implicit_cast(left, result_type);
7815         expression->right     = create_implicit_cast(right, result_type);
7816         expression->base.type = result_type;
7817 }
7818
7819 static void warn_div_by_zero(binary_expression_t const *const expression)
7820 {
7821         if (!is_type_integer(expression->base.type))
7822                 return;
7823
7824         expression_t const *const right = expression->right;
7825         /* The type of the right operand can be different for /= */
7826         if (is_type_integer(right->base.type)                    &&
7827             is_constant_expression(right) == EXPR_CLASS_CONSTANT &&
7828             !fold_constant_to_bool(right)) {
7829                 source_position_t const *const pos = &expression->base.source_position;
7830                 warningf(WARN_DIV_BY_ZERO, pos, "division by zero");
7831         }
7832 }
7833
7834 /**
7835  * Check the semantic restrictions for a div/mod expression.
7836  */
7837 static void semantic_divmod_arithmetic(binary_expression_t *expression)
7838 {
7839         semantic_binexpr_arithmetic(expression);
7840         warn_div_by_zero(expression);
7841 }
7842
7843 static void warn_addsub_in_shift(const expression_t *const expr)
7844 {
7845         if (expr->base.parenthesized)
7846                 return;
7847
7848         char op;
7849         switch (expr->kind) {
7850                 case EXPR_BINARY_ADD: op = '+'; break;
7851                 case EXPR_BINARY_SUB: op = '-'; break;
7852                 default:              return;
7853         }
7854
7855         source_position_t const *const pos = &expr->base.source_position;
7856         warningf(WARN_PARENTHESES, pos, "suggest parentheses around '%c' inside shift", op);
7857 }
7858
7859 static bool semantic_shift(binary_expression_t *expression)
7860 {
7861         expression_t *const left            = expression->left;
7862         expression_t *const right           = expression->right;
7863         type_t       *const orig_type_left  = left->base.type;
7864         type_t       *const orig_type_right = right->base.type;
7865         type_t       *      type_left       = skip_typeref(orig_type_left);
7866         type_t       *      type_right      = skip_typeref(orig_type_right);
7867
7868         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7869                 /* TODO: improve error message */
7870                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7871                         errorf(&expression->base.source_position,
7872                                "operands of shift operation must have integer types");
7873                 }
7874                 return false;
7875         }
7876
7877         type_left = promote_integer(type_left);
7878
7879         if (is_constant_expression(right) == EXPR_CLASS_CONSTANT) {
7880                 source_position_t const *const pos   = &right->base.source_position;
7881                 long                     const count = fold_constant_to_int(right);
7882                 if (count < 0) {
7883                         warningf(WARN_OTHER, pos, "shift count must be non-negative");
7884                 } else if ((unsigned long)count >=
7885                                 get_atomic_type_size(type_left->atomic.akind) * 8) {
7886                         warningf(WARN_OTHER, pos, "shift count must be less than type width");
7887                 }
7888         }
7889
7890         type_right        = promote_integer(type_right);
7891         expression->right = create_implicit_cast(right, type_right);
7892
7893         return true;
7894 }
7895
7896 static void semantic_shift_op(binary_expression_t *expression)
7897 {
7898         expression_t *const left  = expression->left;
7899         expression_t *const right = expression->right;
7900
7901         if (!semantic_shift(expression))
7902                 return;
7903
7904         warn_addsub_in_shift(left);
7905         warn_addsub_in_shift(right);
7906
7907         type_t *const orig_type_left = left->base.type;
7908         type_t *      type_left      = skip_typeref(orig_type_left);
7909
7910         type_left             = promote_integer(type_left);
7911         expression->left      = create_implicit_cast(left, type_left);
7912         expression->base.type = type_left;
7913 }
7914
7915 static void semantic_add(binary_expression_t *expression)
7916 {
7917         expression_t *const left            = expression->left;
7918         expression_t *const right           = expression->right;
7919         type_t       *const orig_type_left  = left->base.type;
7920         type_t       *const orig_type_right = right->base.type;
7921         type_t       *const type_left       = skip_typeref(orig_type_left);
7922         type_t       *const type_right      = skip_typeref(orig_type_right);
7923
7924         /* §6.5.6 */
7925         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7926                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7927                 expression->left  = create_implicit_cast(left, arithmetic_type);
7928                 expression->right = create_implicit_cast(right, arithmetic_type);
7929                 expression->base.type = arithmetic_type;
7930         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7931                 check_pointer_arithmetic(&expression->base.source_position,
7932                                          type_left, orig_type_left);
7933                 expression->base.type = type_left;
7934         } else if (is_type_pointer(type_right) && is_type_integer(type_left)) {
7935                 check_pointer_arithmetic(&expression->base.source_position,
7936                                          type_right, orig_type_right);
7937                 expression->base.type = type_right;
7938         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7939                 errorf(&expression->base.source_position,
7940                        "invalid operands to binary + ('%T', '%T')",
7941                        orig_type_left, orig_type_right);
7942         }
7943 }
7944
7945 static void semantic_sub(binary_expression_t *expression)
7946 {
7947         expression_t            *const left            = expression->left;
7948         expression_t            *const right           = expression->right;
7949         type_t                  *const orig_type_left  = left->base.type;
7950         type_t                  *const orig_type_right = right->base.type;
7951         type_t                  *const type_left       = skip_typeref(orig_type_left);
7952         type_t                  *const type_right      = skip_typeref(orig_type_right);
7953         source_position_t const *const pos             = &expression->base.source_position;
7954
7955         /* §5.6.5 */
7956         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7957                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7958                 expression->left        = create_implicit_cast(left, arithmetic_type);
7959                 expression->right       = create_implicit_cast(right, arithmetic_type);
7960                 expression->base.type =  arithmetic_type;
7961         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7962                 check_pointer_arithmetic(&expression->base.source_position,
7963                                          type_left, orig_type_left);
7964                 expression->base.type = type_left;
7965         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
7966                 type_t *const unqual_left  = get_unqualified_type(skip_typeref(type_left->pointer.points_to));
7967                 type_t *const unqual_right = get_unqualified_type(skip_typeref(type_right->pointer.points_to));
7968                 if (!types_compatible(unqual_left, unqual_right)) {
7969                         errorf(pos,
7970                                "subtracting pointers to incompatible types '%T' and '%T'",
7971                                orig_type_left, orig_type_right);
7972                 } else if (!is_type_object(unqual_left)) {
7973                         if (!is_type_void(unqual_left)) {
7974                                 errorf(pos, "subtracting pointers to non-object types '%T'",
7975                                        orig_type_left);
7976                         } else {
7977                                 warningf(WARN_OTHER, pos, "subtracting pointers to void");
7978                         }
7979                 }
7980                 expression->base.type = type_ptrdiff_t;
7981         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7982                 errorf(pos, "invalid operands of types '%T' and '%T' to binary '-'",
7983                        orig_type_left, orig_type_right);
7984         }
7985 }
7986
7987 static void warn_string_literal_address(expression_t const* expr)
7988 {
7989         while (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7990                 expr = expr->unary.value;
7991                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7992                         return;
7993                 expr = expr->unary.value;
7994         }
7995
7996         if (expr->kind == EXPR_STRING_LITERAL
7997                         || expr->kind == EXPR_WIDE_STRING_LITERAL) {
7998                 source_position_t const *const pos = &expr->base.source_position;
7999                 warningf(WARN_ADDRESS, pos, "comparison with string literal results in unspecified behaviour");
8000         }
8001 }
8002
8003 static bool maybe_negative(expression_t const *const expr)
8004 {
8005         switch (is_constant_expression(expr)) {
8006                 case EXPR_CLASS_ERROR:    return false;
8007                 case EXPR_CLASS_CONSTANT: return constant_is_negative(expr);
8008                 default:                  return true;
8009         }
8010 }
8011
8012 static void warn_comparison(source_position_t const *const pos, expression_t const *const expr, expression_t const *const other)
8013 {
8014         warn_string_literal_address(expr);
8015
8016         expression_t const* const ref = get_reference_address(expr);
8017         if (ref != NULL && is_null_pointer_constant(other)) {
8018                 entity_t const *const ent = ref->reference.entity;
8019                 warningf(WARN_ADDRESS, pos, "the address of '%N' will never be NULL", ent);
8020         }
8021
8022         if (!expr->base.parenthesized) {
8023                 switch (expr->base.kind) {
8024                         case EXPR_BINARY_LESS:
8025                         case EXPR_BINARY_GREATER:
8026                         case EXPR_BINARY_LESSEQUAL:
8027                         case EXPR_BINARY_GREATEREQUAL:
8028                         case EXPR_BINARY_NOTEQUAL:
8029                         case EXPR_BINARY_EQUAL:
8030                                 warningf(WARN_PARENTHESES, pos, "comparisons like 'x <= y < z' do not have their mathematical meaning");
8031                                 break;
8032                         default:
8033                                 break;
8034                 }
8035         }
8036 }
8037
8038 /**
8039  * Check the semantics of comparison expressions.
8040  *
8041  * @param expression   The expression to check.
8042  */
8043 static void semantic_comparison(binary_expression_t *expression)
8044 {
8045         source_position_t const *const pos   = &expression->base.source_position;
8046         expression_t            *const left  = expression->left;
8047         expression_t            *const right = expression->right;
8048
8049         warn_comparison(pos, left, right);
8050         warn_comparison(pos, right, left);
8051
8052         type_t *orig_type_left  = left->base.type;
8053         type_t *orig_type_right = right->base.type;
8054         type_t *type_left       = skip_typeref(orig_type_left);
8055         type_t *type_right      = skip_typeref(orig_type_right);
8056
8057         /* TODO non-arithmetic types */
8058         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8059                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8060
8061                 /* test for signed vs unsigned compares */
8062                 if (is_type_integer(arithmetic_type)) {
8063                         bool const signed_left  = is_type_signed(type_left);
8064                         bool const signed_right = is_type_signed(type_right);
8065                         if (signed_left != signed_right) {
8066                                 /* FIXME long long needs better const folding magic */
8067                                 /* TODO check whether constant value can be represented by other type */
8068                                 if ((signed_left  && maybe_negative(left)) ||
8069                                                 (signed_right && maybe_negative(right))) {
8070                                         warningf(WARN_SIGN_COMPARE, pos, "comparison between signed and unsigned");
8071                                 }
8072                         }
8073                 }
8074
8075                 expression->left        = create_implicit_cast(left, arithmetic_type);
8076                 expression->right       = create_implicit_cast(right, arithmetic_type);
8077                 expression->base.type   = arithmetic_type;
8078                 if ((expression->base.kind == EXPR_BINARY_EQUAL ||
8079                      expression->base.kind == EXPR_BINARY_NOTEQUAL) &&
8080                     is_type_float(arithmetic_type)) {
8081                         warningf(WARN_FLOAT_EQUAL, pos, "comparing floating point with == or != is unsafe");
8082                 }
8083         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
8084                 /* TODO check compatibility */
8085         } else if (is_type_pointer(type_left)) {
8086                 expression->right = create_implicit_cast(right, type_left);
8087         } else if (is_type_pointer(type_right)) {
8088                 expression->left = create_implicit_cast(left, type_right);
8089         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8090                 type_error_incompatible("invalid operands in comparison", pos, type_left, type_right);
8091         }
8092         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8093 }
8094
8095 /**
8096  * Checks if a compound type has constant fields.
8097  */
8098 static bool has_const_fields(const compound_type_t *type)
8099 {
8100         compound_t *compound = type->compound;
8101         entity_t   *entry    = compound->members.entities;
8102
8103         for (; entry != NULL; entry = entry->base.next) {
8104                 if (!is_declaration(entry))
8105                         continue;
8106
8107                 const type_t *decl_type = skip_typeref(entry->declaration.type);
8108                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
8109                         return true;
8110         }
8111
8112         return false;
8113 }
8114
8115 static bool is_valid_assignment_lhs(expression_t const* const left)
8116 {
8117         type_t *const orig_type_left = revert_automatic_type_conversion(left);
8118         type_t *const type_left      = skip_typeref(orig_type_left);
8119
8120         if (!is_lvalue(left)) {
8121                 errorf(&left->base.source_position, "left hand side '%E' of assignment is not an lvalue",
8122                        left);
8123                 return false;
8124         }
8125
8126         if (left->kind == EXPR_REFERENCE
8127                         && left->reference.entity->kind == ENTITY_FUNCTION) {
8128                 errorf(&left->base.source_position, "cannot assign to function '%E'", left);
8129                 return false;
8130         }
8131
8132         if (is_type_array(type_left)) {
8133                 errorf(&left->base.source_position, "cannot assign to array '%E'", left);
8134                 return false;
8135         }
8136         if (type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
8137                 errorf(&left->base.source_position, "assignment to read-only location '%E' (type '%T')", left,
8138                        orig_type_left);
8139                 return false;
8140         }
8141         if (is_type_incomplete(type_left)) {
8142                 errorf(&left->base.source_position, "left-hand side '%E' of assignment has incomplete type '%T'",
8143                        left, orig_type_left);
8144                 return false;
8145         }
8146         if (is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
8147                 errorf(&left->base.source_position, "cannot assign to '%E' because compound type '%T' has read-only fields",
8148                        left, orig_type_left);
8149                 return false;
8150         }
8151
8152         return true;
8153 }
8154
8155 static void semantic_arithmetic_assign(binary_expression_t *expression)
8156 {
8157         expression_t *left            = expression->left;
8158         expression_t *right           = expression->right;
8159         type_t       *orig_type_left  = left->base.type;
8160         type_t       *orig_type_right = right->base.type;
8161
8162         if (!is_valid_assignment_lhs(left))
8163                 return;
8164
8165         type_t *type_left  = skip_typeref(orig_type_left);
8166         type_t *type_right = skip_typeref(orig_type_right);
8167
8168         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
8169                 /* TODO: improve error message */
8170                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8171                         errorf(&expression->base.source_position,
8172                                "operation needs arithmetic types");
8173                 }
8174                 return;
8175         }
8176
8177         /* combined instructions are tricky. We can't create an implicit cast on
8178          * the left side, because we need the uncasted form for the store.
8179          * The ast2firm pass has to know that left_type must be right_type
8180          * for the arithmetic operation and create a cast by itself */
8181         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8182         expression->right       = create_implicit_cast(right, arithmetic_type);
8183         expression->base.type   = type_left;
8184 }
8185
8186 static void semantic_divmod_assign(binary_expression_t *expression)
8187 {
8188         semantic_arithmetic_assign(expression);
8189         warn_div_by_zero(expression);
8190 }
8191
8192 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
8193 {
8194         expression_t *const left            = expression->left;
8195         expression_t *const right           = expression->right;
8196         type_t       *const orig_type_left  = left->base.type;
8197         type_t       *const orig_type_right = right->base.type;
8198         type_t       *const type_left       = skip_typeref(orig_type_left);
8199         type_t       *const type_right      = skip_typeref(orig_type_right);
8200
8201         if (!is_valid_assignment_lhs(left))
8202                 return;
8203
8204         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8205                 /* combined instructions are tricky. We can't create an implicit cast on
8206                  * the left side, because we need the uncasted form for the store.
8207                  * The ast2firm pass has to know that left_type must be right_type
8208                  * for the arithmetic operation and create a cast by itself */
8209                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
8210                 expression->right     = create_implicit_cast(right, arithmetic_type);
8211                 expression->base.type = type_left;
8212         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
8213                 check_pointer_arithmetic(&expression->base.source_position,
8214                                          type_left, orig_type_left);
8215                 expression->base.type = type_left;
8216         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8217                 errorf(&expression->base.source_position,
8218                        "incompatible types '%T' and '%T' in assignment",
8219                        orig_type_left, orig_type_right);
8220         }
8221 }
8222
8223 static void semantic_integer_assign(binary_expression_t *expression)
8224 {
8225         expression_t *left            = expression->left;
8226         expression_t *right           = expression->right;
8227         type_t       *orig_type_left  = left->base.type;
8228         type_t       *orig_type_right = right->base.type;
8229
8230         if (!is_valid_assignment_lhs(left))
8231                 return;
8232
8233         type_t *type_left  = skip_typeref(orig_type_left);
8234         type_t *type_right = skip_typeref(orig_type_right);
8235
8236         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
8237                 /* TODO: improve error message */
8238                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8239                         errorf(&expression->base.source_position,
8240                                "operation needs integer types");
8241                 }
8242                 return;
8243         }
8244
8245         /* combined instructions are tricky. We can't create an implicit cast on
8246          * the left side, because we need the uncasted form for the store.
8247          * The ast2firm pass has to know that left_type must be right_type
8248          * for the arithmetic operation and create a cast by itself */
8249         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8250         expression->right       = create_implicit_cast(right, arithmetic_type);
8251         expression->base.type   = type_left;
8252 }
8253
8254 static void semantic_shift_assign(binary_expression_t *expression)
8255 {
8256         expression_t *left           = expression->left;
8257
8258         if (!is_valid_assignment_lhs(left))
8259                 return;
8260
8261         if (!semantic_shift(expression))
8262                 return;
8263
8264         expression->base.type = skip_typeref(left->base.type);
8265 }
8266
8267 static void warn_logical_and_within_or(const expression_t *const expr)
8268 {
8269         if (expr->base.kind != EXPR_BINARY_LOGICAL_AND)
8270                 return;
8271         if (expr->base.parenthesized)
8272                 return;
8273         source_position_t const *const pos = &expr->base.source_position;
8274         warningf(WARN_PARENTHESES, pos, "suggest parentheses around && within ||");
8275 }
8276
8277 /**
8278  * Check the semantic restrictions of a logical expression.
8279  */
8280 static void semantic_logical_op(binary_expression_t *expression)
8281 {
8282         /* §6.5.13:2  Each of the operands shall have scalar type.
8283          * §6.5.14:2  Each of the operands shall have scalar type. */
8284         semantic_condition(expression->left,   "left operand of logical operator");
8285         semantic_condition(expression->right, "right operand of logical operator");
8286         if (expression->base.kind == EXPR_BINARY_LOGICAL_OR) {
8287                 warn_logical_and_within_or(expression->left);
8288                 warn_logical_and_within_or(expression->right);
8289         }
8290         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8291 }
8292
8293 /**
8294  * Check the semantic restrictions of a binary assign expression.
8295  */
8296 static void semantic_binexpr_assign(binary_expression_t *expression)
8297 {
8298         expression_t *left           = expression->left;
8299         type_t       *orig_type_left = left->base.type;
8300
8301         if (!is_valid_assignment_lhs(left))
8302                 return;
8303
8304         assign_error_t error = semantic_assign(orig_type_left, expression->right);
8305         report_assign_error(error, orig_type_left, expression->right,
8306                         "assignment", &left->base.source_position);
8307         expression->right = create_implicit_cast(expression->right, orig_type_left);
8308         expression->base.type = orig_type_left;
8309 }
8310
8311 /**
8312  * Determine if the outermost operation (or parts thereof) of the given
8313  * expression has no effect in order to generate a warning about this fact.
8314  * Therefore in some cases this only examines some of the operands of the
8315  * expression (see comments in the function and examples below).
8316  * Examples:
8317  *   f() + 23;    // warning, because + has no effect
8318  *   x || f();    // no warning, because x controls execution of f()
8319  *   x ? y : f(); // warning, because y has no effect
8320  *   (void)x;     // no warning to be able to suppress the warning
8321  * This function can NOT be used for an "expression has definitely no effect"-
8322  * analysis. */
8323 static bool expression_has_effect(const expression_t *const expr)
8324 {
8325         switch (expr->kind) {
8326                 case EXPR_ERROR:                      return true; /* do NOT warn */
8327                 case EXPR_REFERENCE:                  return false;
8328                 case EXPR_ENUM_CONSTANT:              return false;
8329                 case EXPR_LABEL_ADDRESS:              return false;
8330
8331                 /* suppress the warning for microsoft __noop operations */
8332                 case EXPR_LITERAL_MS_NOOP:            return true;
8333                 case EXPR_LITERAL_BOOLEAN:
8334                 case EXPR_LITERAL_CHARACTER:
8335                 case EXPR_LITERAL_WIDE_CHARACTER:
8336                 case EXPR_LITERAL_INTEGER:
8337                 case EXPR_LITERAL_FLOATINGPOINT:
8338                 case EXPR_STRING_LITERAL:             return false;
8339                 case EXPR_WIDE_STRING_LITERAL:        return false;
8340
8341                 case EXPR_CALL: {
8342                         const call_expression_t *const call = &expr->call;
8343                         if (call->function->kind != EXPR_REFERENCE)
8344                                 return true;
8345
8346                         switch (call->function->reference.entity->function.btk) {
8347                                 /* FIXME: which builtins have no effect? */
8348                                 default:                      return true;
8349                         }
8350                 }
8351
8352                 /* Generate the warning if either the left or right hand side of a
8353                  * conditional expression has no effect */
8354                 case EXPR_CONDITIONAL: {
8355                         conditional_expression_t const *const cond = &expr->conditional;
8356                         expression_t             const *const t    = cond->true_expression;
8357                         return
8358                                 (t == NULL || expression_has_effect(t)) &&
8359                                 expression_has_effect(cond->false_expression);
8360                 }
8361
8362                 case EXPR_SELECT:                     return false;
8363                 case EXPR_ARRAY_ACCESS:               return false;
8364                 case EXPR_SIZEOF:                     return false;
8365                 case EXPR_CLASSIFY_TYPE:              return false;
8366                 case EXPR_ALIGNOF:                    return false;
8367
8368                 case EXPR_FUNCNAME:                   return false;
8369                 case EXPR_BUILTIN_CONSTANT_P:         return false;
8370                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P: return false;
8371                 case EXPR_OFFSETOF:                   return false;
8372                 case EXPR_VA_START:                   return true;
8373                 case EXPR_VA_ARG:                     return true;
8374                 case EXPR_VA_COPY:                    return true;
8375                 case EXPR_STATEMENT:                  return true; // TODO
8376                 case EXPR_COMPOUND_LITERAL:           return false;
8377
8378                 case EXPR_UNARY_NEGATE:               return false;
8379                 case EXPR_UNARY_PLUS:                 return false;
8380                 case EXPR_UNARY_BITWISE_NEGATE:       return false;
8381                 case EXPR_UNARY_NOT:                  return false;
8382                 case EXPR_UNARY_DEREFERENCE:          return false;
8383                 case EXPR_UNARY_TAKE_ADDRESS:         return false;
8384                 case EXPR_UNARY_POSTFIX_INCREMENT:    return true;
8385                 case EXPR_UNARY_POSTFIX_DECREMENT:    return true;
8386                 case EXPR_UNARY_PREFIX_INCREMENT:     return true;
8387                 case EXPR_UNARY_PREFIX_DECREMENT:     return true;
8388
8389                 /* Treat void casts as if they have an effect in order to being able to
8390                  * suppress the warning */
8391                 case EXPR_UNARY_CAST: {
8392                         type_t *const type = skip_typeref(expr->base.type);
8393                         return is_type_void(type);
8394                 }
8395
8396                 case EXPR_UNARY_ASSUME:               return true;
8397                 case EXPR_UNARY_DELETE:               return true;
8398                 case EXPR_UNARY_DELETE_ARRAY:         return true;
8399                 case EXPR_UNARY_THROW:                return true;
8400
8401                 case EXPR_BINARY_ADD:                 return false;
8402                 case EXPR_BINARY_SUB:                 return false;
8403                 case EXPR_BINARY_MUL:                 return false;
8404                 case EXPR_BINARY_DIV:                 return false;
8405                 case EXPR_BINARY_MOD:                 return false;
8406                 case EXPR_BINARY_EQUAL:               return false;
8407                 case EXPR_BINARY_NOTEQUAL:            return false;
8408                 case EXPR_BINARY_LESS:                return false;
8409                 case EXPR_BINARY_LESSEQUAL:           return false;
8410                 case EXPR_BINARY_GREATER:             return false;
8411                 case EXPR_BINARY_GREATEREQUAL:        return false;
8412                 case EXPR_BINARY_BITWISE_AND:         return false;
8413                 case EXPR_BINARY_BITWISE_OR:          return false;
8414                 case EXPR_BINARY_BITWISE_XOR:         return false;
8415                 case EXPR_BINARY_SHIFTLEFT:           return false;
8416                 case EXPR_BINARY_SHIFTRIGHT:          return false;
8417                 case EXPR_BINARY_ASSIGN:              return true;
8418                 case EXPR_BINARY_MUL_ASSIGN:          return true;
8419                 case EXPR_BINARY_DIV_ASSIGN:          return true;
8420                 case EXPR_BINARY_MOD_ASSIGN:          return true;
8421                 case EXPR_BINARY_ADD_ASSIGN:          return true;
8422                 case EXPR_BINARY_SUB_ASSIGN:          return true;
8423                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:    return true;
8424                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:   return true;
8425                 case EXPR_BINARY_BITWISE_AND_ASSIGN:  return true;
8426                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:  return true;
8427                 case EXPR_BINARY_BITWISE_OR_ASSIGN:   return true;
8428
8429                 /* Only examine the right hand side of && and ||, because the left hand
8430                  * side already has the effect of controlling the execution of the right
8431                  * hand side */
8432                 case EXPR_BINARY_LOGICAL_AND:
8433                 case EXPR_BINARY_LOGICAL_OR:
8434                 /* Only examine the right hand side of a comma expression, because the left
8435                  * hand side has a separate warning */
8436                 case EXPR_BINARY_COMMA:
8437                         return expression_has_effect(expr->binary.right);
8438
8439                 case EXPR_BINARY_ISGREATER:           return false;
8440                 case EXPR_BINARY_ISGREATEREQUAL:      return false;
8441                 case EXPR_BINARY_ISLESS:              return false;
8442                 case EXPR_BINARY_ISLESSEQUAL:         return false;
8443                 case EXPR_BINARY_ISLESSGREATER:       return false;
8444                 case EXPR_BINARY_ISUNORDERED:         return false;
8445         }
8446
8447         internal_errorf(HERE, "unexpected expression");
8448 }
8449
8450 static void semantic_comma(binary_expression_t *expression)
8451 {
8452         const expression_t *const left = expression->left;
8453         if (!expression_has_effect(left)) {
8454                 source_position_t const *const pos = &left->base.source_position;
8455                 warningf(WARN_UNUSED_VALUE, pos, "left-hand operand of comma expression has no effect");
8456         }
8457         expression->base.type = expression->right->base.type;
8458 }
8459
8460 /**
8461  * @param prec_r precedence of the right operand
8462  */
8463 #define CREATE_BINEXPR_PARSER(token_kind, binexpression_type, prec_r, sfunc) \
8464 static expression_t *parse_##binexpression_type(expression_t *left)          \
8465 {                                                                            \
8466         expression_t *binexpr = allocate_expression_zero(binexpression_type);    \
8467         binexpr->binary.left  = left;                                            \
8468         eat(token_kind);                                                         \
8469                                                                              \
8470         expression_t *right = parse_subexpression(prec_r);                       \
8471                                                                              \
8472         binexpr->binary.right = right;                                           \
8473         sfunc(&binexpr->binary);                                                 \
8474                                                                              \
8475         return binexpr;                                                          \
8476 }
8477
8478 CREATE_BINEXPR_PARSER('*',                    EXPR_BINARY_MUL,                PREC_CAST,           semantic_binexpr_arithmetic)
8479 CREATE_BINEXPR_PARSER('/',                    EXPR_BINARY_DIV,                PREC_CAST,           semantic_divmod_arithmetic)
8480 CREATE_BINEXPR_PARSER('%',                    EXPR_BINARY_MOD,                PREC_CAST,           semantic_divmod_arithmetic)
8481 CREATE_BINEXPR_PARSER('+',                    EXPR_BINARY_ADD,                PREC_MULTIPLICATIVE, semantic_add)
8482 CREATE_BINEXPR_PARSER('-',                    EXPR_BINARY_SUB,                PREC_MULTIPLICATIVE, semantic_sub)
8483 CREATE_BINEXPR_PARSER(T_LESSLESS,             EXPR_BINARY_SHIFTLEFT,          PREC_ADDITIVE,       semantic_shift_op)
8484 CREATE_BINEXPR_PARSER(T_GREATERGREATER,       EXPR_BINARY_SHIFTRIGHT,         PREC_ADDITIVE,       semantic_shift_op)
8485 CREATE_BINEXPR_PARSER('<',                    EXPR_BINARY_LESS,               PREC_SHIFT,          semantic_comparison)
8486 CREATE_BINEXPR_PARSER('>',                    EXPR_BINARY_GREATER,            PREC_SHIFT,          semantic_comparison)
8487 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,          PREC_SHIFT,          semantic_comparison)
8488 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,       PREC_SHIFT,          semantic_comparison)
8489 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,           PREC_RELATIONAL,     semantic_comparison)
8490 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,              PREC_RELATIONAL,     semantic_comparison)
8491 CREATE_BINEXPR_PARSER('&',                    EXPR_BINARY_BITWISE_AND,        PREC_EQUALITY,       semantic_binexpr_integer)
8492 CREATE_BINEXPR_PARSER('^',                    EXPR_BINARY_BITWISE_XOR,        PREC_AND,            semantic_binexpr_integer)
8493 CREATE_BINEXPR_PARSER('|',                    EXPR_BINARY_BITWISE_OR,         PREC_XOR,            semantic_binexpr_integer)
8494 CREATE_BINEXPR_PARSER(T_ANDAND,               EXPR_BINARY_LOGICAL_AND,        PREC_OR,             semantic_logical_op)
8495 CREATE_BINEXPR_PARSER(T_PIPEPIPE,             EXPR_BINARY_LOGICAL_OR,         PREC_LOGICAL_AND,    semantic_logical_op)
8496 CREATE_BINEXPR_PARSER('=',                    EXPR_BINARY_ASSIGN,             PREC_ASSIGNMENT,     semantic_binexpr_assign)
8497 CREATE_BINEXPR_PARSER(T_PLUSEQUAL,            EXPR_BINARY_ADD_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8498 CREATE_BINEXPR_PARSER(T_MINUSEQUAL,           EXPR_BINARY_SUB_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8499 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL,        EXPR_BINARY_MUL_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_assign)
8500 CREATE_BINEXPR_PARSER(T_SLASHEQUAL,           EXPR_BINARY_DIV_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8501 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL,         EXPR_BINARY_MOD_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8502 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL,        EXPR_BINARY_SHIFTLEFT_ASSIGN,   PREC_ASSIGNMENT,     semantic_shift_assign)
8503 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL,  EXPR_BINARY_SHIFTRIGHT_ASSIGN,  PREC_ASSIGNMENT,     semantic_shift_assign)
8504 CREATE_BINEXPR_PARSER(T_ANDEQUAL,             EXPR_BINARY_BITWISE_AND_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8505 CREATE_BINEXPR_PARSER(T_PIPEEQUAL,            EXPR_BINARY_BITWISE_OR_ASSIGN,  PREC_ASSIGNMENT,     semantic_integer_assign)
8506 CREATE_BINEXPR_PARSER(T_CARETEQUAL,           EXPR_BINARY_BITWISE_XOR_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8507 CREATE_BINEXPR_PARSER(',',                    EXPR_BINARY_COMMA,              PREC_ASSIGNMENT,     semantic_comma)
8508
8509
8510 static expression_t *parse_subexpression(precedence_t precedence)
8511 {
8512         expression_parser_function_t *parser
8513                 = &expression_parsers[token.kind];
8514         expression_t                 *left;
8515
8516         if (parser->parser != NULL) {
8517                 left = parser->parser();
8518         } else {
8519                 left = parse_primary_expression();
8520         }
8521         assert(left != NULL);
8522
8523         while (true) {
8524                 parser = &expression_parsers[token.kind];
8525                 if (parser->infix_parser == NULL)
8526                         break;
8527                 if (parser->infix_precedence < precedence)
8528                         break;
8529
8530                 left = parser->infix_parser(left);
8531
8532                 assert(left != NULL);
8533         }
8534
8535         return left;
8536 }
8537
8538 /**
8539  * Parse an expression.
8540  */
8541 static expression_t *parse_expression(void)
8542 {
8543         return parse_subexpression(PREC_EXPRESSION);
8544 }
8545
8546 /**
8547  * Register a parser for a prefix-like operator.
8548  *
8549  * @param parser      the parser function
8550  * @param token_kind  the token type of the prefix token
8551  */
8552 static void register_expression_parser(parse_expression_function parser,
8553                                        int token_kind)
8554 {
8555         expression_parser_function_t *entry = &expression_parsers[token_kind];
8556
8557         if (entry->parser != NULL) {
8558                 diagnosticf("for token '%k'\n", (token_kind_t)token_kind);
8559                 panic("trying to register multiple expression parsers for a token");
8560         }
8561         entry->parser = parser;
8562 }
8563
8564 /**
8565  * Register a parser for an infix operator with given precedence.
8566  *
8567  * @param parser      the parser function
8568  * @param token_kind  the token type of the infix operator
8569  * @param precedence  the precedence of the operator
8570  */
8571 static void register_infix_parser(parse_expression_infix_function parser,
8572                                   int token_kind, precedence_t precedence)
8573 {
8574         expression_parser_function_t *entry = &expression_parsers[token_kind];
8575
8576         if (entry->infix_parser != NULL) {
8577                 diagnosticf("for token '%k'\n", (token_kind_t)token_kind);
8578                 panic("trying to register multiple infix expression parsers for a "
8579                       "token");
8580         }
8581         entry->infix_parser     = parser;
8582         entry->infix_precedence = precedence;
8583 }
8584
8585 /**
8586  * Initialize the expression parsers.
8587  */
8588 static void init_expression_parsers(void)
8589 {
8590         memset(&expression_parsers, 0, sizeof(expression_parsers));
8591
8592         register_infix_parser(parse_array_expression,               '[',                    PREC_POSTFIX);
8593         register_infix_parser(parse_call_expression,                '(',                    PREC_POSTFIX);
8594         register_infix_parser(parse_select_expression,              '.',                    PREC_POSTFIX);
8595         register_infix_parser(parse_select_expression,              T_MINUSGREATER,         PREC_POSTFIX);
8596         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,   T_PLUSPLUS,             PREC_POSTFIX);
8597         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,   T_MINUSMINUS,           PREC_POSTFIX);
8598         register_infix_parser(parse_EXPR_BINARY_MUL,                '*',                    PREC_MULTIPLICATIVE);
8599         register_infix_parser(parse_EXPR_BINARY_DIV,                '/',                    PREC_MULTIPLICATIVE);
8600         register_infix_parser(parse_EXPR_BINARY_MOD,                '%',                    PREC_MULTIPLICATIVE);
8601         register_infix_parser(parse_EXPR_BINARY_ADD,                '+',                    PREC_ADDITIVE);
8602         register_infix_parser(parse_EXPR_BINARY_SUB,                '-',                    PREC_ADDITIVE);
8603         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,          T_LESSLESS,             PREC_SHIFT);
8604         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,         T_GREATERGREATER,       PREC_SHIFT);
8605         register_infix_parser(parse_EXPR_BINARY_LESS,               '<',                    PREC_RELATIONAL);
8606         register_infix_parser(parse_EXPR_BINARY_GREATER,            '>',                    PREC_RELATIONAL);
8607         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,          T_LESSEQUAL,            PREC_RELATIONAL);
8608         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL,       T_GREATEREQUAL,         PREC_RELATIONAL);
8609         register_infix_parser(parse_EXPR_BINARY_EQUAL,              T_EQUALEQUAL,           PREC_EQUALITY);
8610         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,           T_EXCLAMATIONMARKEQUAL, PREC_EQUALITY);
8611         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,        '&',                    PREC_AND);
8612         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,        '^',                    PREC_XOR);
8613         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,         '|',                    PREC_OR);
8614         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,        T_ANDAND,               PREC_LOGICAL_AND);
8615         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,         T_PIPEPIPE,             PREC_LOGICAL_OR);
8616         register_infix_parser(parse_conditional_expression,         '?',                    PREC_CONDITIONAL);
8617         register_infix_parser(parse_EXPR_BINARY_ASSIGN,             '=',                    PREC_ASSIGNMENT);
8618         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,         T_PLUSEQUAL,            PREC_ASSIGNMENT);
8619         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,         T_MINUSEQUAL,           PREC_ASSIGNMENT);
8620         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,         T_ASTERISKEQUAL,        PREC_ASSIGNMENT);
8621         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,         T_SLASHEQUAL,           PREC_ASSIGNMENT);
8622         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,         T_PERCENTEQUAL,         PREC_ASSIGNMENT);
8623         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,   T_LESSLESSEQUAL,        PREC_ASSIGNMENT);
8624         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,  T_GREATERGREATEREQUAL,  PREC_ASSIGNMENT);
8625         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN, T_ANDEQUAL,             PREC_ASSIGNMENT);
8626         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,  T_PIPEEQUAL,            PREC_ASSIGNMENT);
8627         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN, T_CARETEQUAL,           PREC_ASSIGNMENT);
8628         register_infix_parser(parse_EXPR_BINARY_COMMA,              ',',                    PREC_EXPRESSION);
8629
8630         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-');
8631         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+');
8632         register_expression_parser(parse_EXPR_UNARY_NOT,              '!');
8633         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~');
8634         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*');
8635         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&');
8636         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT, T_PLUSPLUS);
8637         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT, T_MINUSMINUS);
8638         register_expression_parser(parse_sizeof,                      T_sizeof);
8639         register_expression_parser(parse_alignof,                     T___alignof__);
8640         register_expression_parser(parse_extension,                   T___extension__);
8641         register_expression_parser(parse_builtin_classify_type,       T___builtin_classify_type);
8642         register_expression_parser(parse_delete,                      T_delete);
8643         register_expression_parser(parse_throw,                       T_throw);
8644 }
8645
8646 /**
8647  * Parse a asm statement arguments specification.
8648  */
8649 static asm_argument_t *parse_asm_arguments(bool is_out)
8650 {
8651         asm_argument_t  *result = NULL;
8652         asm_argument_t **anchor = &result;
8653
8654         while (token.kind == T_STRING_LITERAL || token.kind == '[') {
8655                 asm_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
8656
8657                 if (next_if('[')) {
8658                         add_anchor_token(']');
8659                         argument->symbol = expect_identifier("while parsing asm argument", NULL);
8660                         rem_anchor_token(']');
8661                         expect(']');
8662                         if (!argument->symbol)
8663                                 return NULL;
8664                 }
8665
8666                 argument->constraints = parse_string_literals();
8667                 add_anchor_token(')');
8668                 expect('(');
8669                 expression_t *expression = parse_expression();
8670                 rem_anchor_token(')');
8671                 if (is_out) {
8672                         /* Ugly GCC stuff: Allow lvalue casts.  Skip casts, when they do not
8673                          * change size or type representation (e.g. int -> long is ok, but
8674                          * int -> float is not) */
8675                         if (expression->kind == EXPR_UNARY_CAST) {
8676                                 type_t      *const type = expression->base.type;
8677                                 type_kind_t  const kind = type->kind;
8678                                 if (kind == TYPE_ATOMIC || kind == TYPE_POINTER) {
8679                                         unsigned flags;
8680                                         unsigned size;
8681                                         if (kind == TYPE_ATOMIC) {
8682                                                 atomic_type_kind_t const akind = type->atomic.akind;
8683                                                 flags = get_atomic_type_flags(akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8684                                                 size  = get_atomic_type_size(akind);
8685                                         } else {
8686                                                 flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8687                                                 size  = get_type_size(type_void_ptr);
8688                                         }
8689
8690                                         do {
8691                                                 expression_t *const value      = expression->unary.value;
8692                                                 type_t       *const value_type = value->base.type;
8693                                                 type_kind_t   const value_kind = value_type->kind;
8694
8695                                                 unsigned value_flags;
8696                                                 unsigned value_size;
8697                                                 if (value_kind == TYPE_ATOMIC) {
8698                                                         atomic_type_kind_t const value_akind = value_type->atomic.akind;
8699                                                         value_flags = get_atomic_type_flags(value_akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8700                                                         value_size  = get_atomic_type_size(value_akind);
8701                                                 } else if (value_kind == TYPE_POINTER) {
8702                                                         value_flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8703                                                         value_size  = get_type_size(type_void_ptr);
8704                                                 } else {
8705                                                         break;
8706                                                 }
8707
8708                                                 if (value_flags != flags || value_size != size)
8709                                                         break;
8710
8711                                                 expression = value;
8712                                         } while (expression->kind == EXPR_UNARY_CAST);
8713                                 }
8714                         }
8715
8716                         if (!is_lvalue(expression)) {
8717                                 errorf(&expression->base.source_position,
8718                                        "asm output argument is not an lvalue");
8719                         }
8720
8721                         if (argument->constraints.begin[0] == '=')
8722                                 determine_lhs_ent(expression, NULL);
8723                         else
8724                                 mark_vars_read(expression, NULL);
8725                 } else {
8726                         mark_vars_read(expression, NULL);
8727                 }
8728                 argument->expression = expression;
8729                 expect(')');
8730
8731                 set_address_taken(expression, true);
8732
8733                 *anchor = argument;
8734                 anchor  = &argument->next;
8735
8736                 if (!next_if(','))
8737                         break;
8738         }
8739
8740         return result;
8741 }
8742
8743 /**
8744  * Parse a asm statement clobber specification.
8745  */
8746 static asm_clobber_t *parse_asm_clobbers(void)
8747 {
8748         asm_clobber_t *result  = NULL;
8749         asm_clobber_t **anchor = &result;
8750
8751         while (token.kind == T_STRING_LITERAL) {
8752                 asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
8753                 clobber->clobber       = parse_string_literals();
8754
8755                 *anchor = clobber;
8756                 anchor  = &clobber->next;
8757
8758                 if (!next_if(','))
8759                         break;
8760         }
8761
8762         return result;
8763 }
8764
8765 /**
8766  * Parse an asm statement.
8767  */
8768 static statement_t *parse_asm_statement(void)
8769 {
8770         statement_t     *statement     = allocate_statement_zero(STATEMENT_ASM);
8771         asm_statement_t *asm_statement = &statement->asms;
8772
8773         eat(T_asm);
8774
8775         if (next_if(T_volatile))
8776                 asm_statement->is_volatile = true;
8777
8778         expect('(');
8779         add_anchor_token(')');
8780         if (token.kind != T_STRING_LITERAL) {
8781                 parse_error_expected("after asm(", T_STRING_LITERAL, NULL);
8782                 goto end_of_asm;
8783         }
8784         asm_statement->asm_text = parse_string_literals();
8785
8786         add_anchor_token(':');
8787         if (!next_if(':')) {
8788                 rem_anchor_token(':');
8789                 goto end_of_asm;
8790         }
8791
8792         asm_statement->outputs = parse_asm_arguments(true);
8793         if (!next_if(':')) {
8794                 rem_anchor_token(':');
8795                 goto end_of_asm;
8796         }
8797
8798         asm_statement->inputs = parse_asm_arguments(false);
8799         if (!next_if(':')) {
8800                 rem_anchor_token(':');
8801                 goto end_of_asm;
8802         }
8803         rem_anchor_token(':');
8804
8805         asm_statement->clobbers = parse_asm_clobbers();
8806
8807 end_of_asm:
8808         rem_anchor_token(')');
8809         expect(')');
8810         expect(';');
8811
8812         if (asm_statement->outputs == NULL) {
8813                 /* GCC: An 'asm' instruction without any output operands will be treated
8814                  * identically to a volatile 'asm' instruction. */
8815                 asm_statement->is_volatile = true;
8816         }
8817
8818         return statement;
8819 }
8820
8821 static statement_t *parse_label_inner_statement(statement_t const *const label, char const *const label_kind)
8822 {
8823         statement_t *inner_stmt;
8824         switch (token.kind) {
8825                 case '}':
8826                         errorf(&label->base.source_position, "%s at end of compound statement", label_kind);
8827                         inner_stmt = create_error_statement();
8828                         break;
8829
8830                 case ';':
8831                         if (label->kind == STATEMENT_LABEL) {
8832                                 /* Eat an empty statement here, to avoid the warning about an empty
8833                                  * statement after a label.  label:; is commonly used to have a label
8834                                  * before a closing brace. */
8835                                 inner_stmt = create_empty_statement();
8836                                 eat(';');
8837                                 break;
8838                         }
8839                         /* FALLTHROUGH */
8840
8841                 default:
8842                         inner_stmt = parse_statement();
8843                         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
8844                         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
8845                         if (inner_stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
8846                                 errorf(&inner_stmt->base.source_position, "declaration after %s", label_kind);
8847                         }
8848                         break;
8849         }
8850         return inner_stmt;
8851 }
8852
8853 /**
8854  * Parse a case statement.
8855  */
8856 static statement_t *parse_case_statement(void)
8857 {
8858         statement_t       *const statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8859         source_position_t *const pos       = &statement->base.source_position;
8860
8861         eat(T_case);
8862         add_anchor_token(':');
8863
8864         expression_t *expression = parse_expression();
8865         type_t *expression_type = expression->base.type;
8866         type_t *skipped         = skip_typeref(expression_type);
8867         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8868                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8869                        expression, expression_type);
8870         }
8871
8872         type_t *type = expression_type;
8873         if (current_switch != NULL) {
8874                 type_t *switch_type = current_switch->expression->base.type;
8875                 if (is_type_valid(switch_type)) {
8876                         expression = create_implicit_cast(expression, switch_type);
8877                 }
8878         }
8879
8880         statement->case_label.expression = expression;
8881         expression_classification_t const expr_class = is_constant_expression(expression);
8882         if (expr_class != EXPR_CLASS_CONSTANT) {
8883                 if (expr_class != EXPR_CLASS_ERROR) {
8884                         errorf(pos, "case label does not reduce to an integer constant");
8885                 }
8886                 statement->case_label.is_bad = true;
8887         } else {
8888                 long const val = fold_constant_to_int(expression);
8889                 statement->case_label.first_case = val;
8890                 statement->case_label.last_case  = val;
8891         }
8892
8893         if (GNU_MODE) {
8894                 if (next_if(T_DOTDOTDOT)) {
8895                         expression_t *end_range = parse_expression();
8896                         expression_type = expression->base.type;
8897                         skipped         = skip_typeref(expression_type);
8898                         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8899                                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8900                                            expression, expression_type);
8901                         }
8902
8903                         end_range = create_implicit_cast(end_range, type);
8904                         statement->case_label.end_range = end_range;
8905                         expression_classification_t const end_class = is_constant_expression(end_range);
8906                         if (end_class != EXPR_CLASS_CONSTANT) {
8907                                 if (end_class != EXPR_CLASS_ERROR) {
8908                                         errorf(pos, "case range does not reduce to an integer constant");
8909                                 }
8910                                 statement->case_label.is_bad = true;
8911                         } else {
8912                                 long const val = fold_constant_to_int(end_range);
8913                                 statement->case_label.last_case = val;
8914
8915                                 if (val < statement->case_label.first_case) {
8916                                         statement->case_label.is_empty_range = true;
8917                                         warningf(WARN_OTHER, pos, "empty range specified");
8918                                 }
8919                         }
8920                 }
8921         }
8922
8923         PUSH_PARENT(statement);
8924
8925         rem_anchor_token(':');
8926         expect(':');
8927
8928         if (current_switch != NULL) {
8929                 if (! statement->case_label.is_bad) {
8930                         /* Check for duplicate case values */
8931                         case_label_statement_t *c = &statement->case_label;
8932                         for (case_label_statement_t *l = current_switch->first_case; l != NULL; l = l->next) {
8933                                 if (l->is_bad || l->is_empty_range || l->expression == NULL)
8934                                         continue;
8935
8936                                 if (c->last_case < l->first_case || c->first_case > l->last_case)
8937                                         continue;
8938
8939                                 errorf(pos, "duplicate case value (previously used %P)",
8940                                        &l->base.source_position);
8941                                 break;
8942                         }
8943                 }
8944                 /* link all cases into the switch statement */
8945                 if (current_switch->last_case == NULL) {
8946                         current_switch->first_case      = &statement->case_label;
8947                 } else {
8948                         current_switch->last_case->next = &statement->case_label;
8949                 }
8950                 current_switch->last_case = &statement->case_label;
8951         } else {
8952                 errorf(pos, "case label not within a switch statement");
8953         }
8954
8955         statement->case_label.statement = parse_label_inner_statement(statement, "case label");
8956
8957         POP_PARENT();
8958         return statement;
8959 }
8960
8961 /**
8962  * Parse a default statement.
8963  */
8964 static statement_t *parse_default_statement(void)
8965 {
8966         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8967
8968         eat(T_default);
8969
8970         PUSH_PARENT(statement);
8971
8972         expect(':');
8973
8974         if (current_switch != NULL) {
8975                 const case_label_statement_t *def_label = current_switch->default_label;
8976                 if (def_label != NULL) {
8977                         errorf(&statement->base.source_position, "multiple default labels in one switch (previous declared %P)", &def_label->base.source_position);
8978                 } else {
8979                         current_switch->default_label = &statement->case_label;
8980
8981                         /* link all cases into the switch statement */
8982                         if (current_switch->last_case == NULL) {
8983                                 current_switch->first_case      = &statement->case_label;
8984                         } else {
8985                                 current_switch->last_case->next = &statement->case_label;
8986                         }
8987                         current_switch->last_case = &statement->case_label;
8988                 }
8989         } else {
8990                 errorf(&statement->base.source_position,
8991                         "'default' label not within a switch statement");
8992         }
8993
8994         statement->case_label.statement = parse_label_inner_statement(statement, "default label");
8995
8996         POP_PARENT();
8997         return statement;
8998 }
8999
9000 /**
9001  * Parse a label statement.
9002  */
9003 static statement_t *parse_label_statement(void)
9004 {
9005         statement_t *const statement = allocate_statement_zero(STATEMENT_LABEL);
9006         label_t     *const label     = get_label(NULL /* Cannot fail, token is T_IDENTIFIER. */);
9007         statement->label.label = label;
9008
9009         PUSH_PARENT(statement);
9010
9011         /* if statement is already set then the label is defined twice,
9012          * otherwise it was just mentioned in a goto/local label declaration so far
9013          */
9014         source_position_t const* const pos = &statement->base.source_position;
9015         if (label->statement != NULL) {
9016                 errorf(pos, "duplicate '%N' (declared %P)", (entity_t const*)label, &label->base.source_position);
9017         } else {
9018                 label->base.source_position = *pos;
9019                 label->statement            = statement;
9020         }
9021
9022         eat(':');
9023
9024         if (token.kind == T___attribute__ && !(c_mode & _CXX)) {
9025                 parse_attributes(NULL); // TODO process attributes
9026         }
9027
9028         statement->label.statement = parse_label_inner_statement(statement, "label");
9029
9030         /* remember the labels in a list for later checking */
9031         *label_anchor = &statement->label;
9032         label_anchor  = &statement->label.next;
9033
9034         POP_PARENT();
9035         return statement;
9036 }
9037
9038 static statement_t *parse_inner_statement(void)
9039 {
9040         statement_t *const stmt = parse_statement();
9041         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
9042         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
9043         if (stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
9044                 errorf(&stmt->base.source_position, "declaration as inner statement, use {}");
9045         }
9046         return stmt;
9047 }
9048
9049 /**
9050  * Parse an expression in parentheses and mark its variables as read.
9051  */
9052 static expression_t *parse_condition(void)
9053 {
9054         add_anchor_token(')');
9055         expect('(');
9056         expression_t *const expr = parse_expression();
9057         mark_vars_read(expr, NULL);
9058         rem_anchor_token(')');
9059         expect(')');
9060         return expr;
9061 }
9062
9063 /**
9064  * Parse an if statement.
9065  */
9066 static statement_t *parse_if(void)
9067 {
9068         statement_t *statement = allocate_statement_zero(STATEMENT_IF);
9069
9070         eat(T_if);
9071
9072         PUSH_PARENT(statement);
9073         PUSH_SCOPE_STATEMENT(&statement->ifs.scope);
9074
9075         add_anchor_token(T_else);
9076
9077         expression_t *const expr = parse_condition();
9078         statement->ifs.condition = expr;
9079         /* §6.8.4.1:1  The controlling expression of an if statement shall have
9080          *             scalar type. */
9081         semantic_condition(expr, "condition of 'if'-statment");
9082
9083         statement_t *const true_stmt = parse_inner_statement();
9084         statement->ifs.true_statement = true_stmt;
9085         rem_anchor_token(T_else);
9086
9087         if (true_stmt->kind == STATEMENT_EMPTY) {
9088                 warningf(WARN_EMPTY_BODY, HERE,
9089                         "suggest braces around empty body in an ‘if’ statement");
9090         }
9091
9092         if (next_if(T_else)) {
9093                 statement->ifs.false_statement = parse_inner_statement();
9094
9095                 if (statement->ifs.false_statement->kind == STATEMENT_EMPTY) {
9096                         warningf(WARN_EMPTY_BODY, HERE,
9097                                         "suggest braces around empty body in an ‘if’ statement");
9098                 }
9099         } else if (true_stmt->kind == STATEMENT_IF &&
9100                         true_stmt->ifs.false_statement != NULL) {
9101                 source_position_t const *const pos = &true_stmt->base.source_position;
9102                 warningf(WARN_PARENTHESES, pos, "suggest explicit braces to avoid ambiguous 'else'");
9103         }
9104
9105         POP_SCOPE();
9106         POP_PARENT();
9107         return statement;
9108 }
9109
9110 /**
9111  * Check that all enums are handled in a switch.
9112  *
9113  * @param statement  the switch statement to check
9114  */
9115 static void check_enum_cases(const switch_statement_t *statement)
9116 {
9117         if (!is_warn_on(WARN_SWITCH_ENUM))
9118                 return;
9119         const type_t *type = skip_typeref(statement->expression->base.type);
9120         if (! is_type_enum(type))
9121                 return;
9122         const enum_type_t *enumt = &type->enumt;
9123
9124         /* if we have a default, no warnings */
9125         if (statement->default_label != NULL)
9126                 return;
9127
9128         /* FIXME: calculation of value should be done while parsing */
9129         /* TODO: quadratic algorithm here. Change to an n log n one */
9130         long            last_value = -1;
9131         const entity_t *entry      = enumt->enume->base.next;
9132         for (; entry != NULL && entry->kind == ENTITY_ENUM_VALUE;
9133              entry = entry->base.next) {
9134                 const expression_t *expression = entry->enum_value.value;
9135                 long                value      = expression != NULL ? fold_constant_to_int(expression) : last_value + 1;
9136                 bool                found      = false;
9137                 for (const case_label_statement_t *l = statement->first_case; l != NULL; l = l->next) {
9138                         if (l->expression == NULL)
9139                                 continue;
9140                         if (l->first_case <= value && value <= l->last_case) {
9141                                 found = true;
9142                                 break;
9143                         }
9144                 }
9145                 if (!found) {
9146                         source_position_t const *const pos = &statement->base.source_position;
9147                         warningf(WARN_SWITCH_ENUM, pos, "'%N' not handled in switch", entry);
9148                 }
9149                 last_value = value;
9150         }
9151 }
9152
9153 /**
9154  * Parse a switch statement.
9155  */
9156 static statement_t *parse_switch(void)
9157 {
9158         statement_t *statement = allocate_statement_zero(STATEMENT_SWITCH);
9159
9160         eat(T_switch);
9161
9162         PUSH_PARENT(statement);
9163         PUSH_SCOPE_STATEMENT(&statement->switchs.scope);
9164
9165         expression_t *const expr = parse_condition();
9166         type_t       *      type = skip_typeref(expr->base.type);
9167         if (is_type_integer(type)) {
9168                 type = promote_integer(type);
9169                 if (get_akind_rank(get_akind(type)) >= get_akind_rank(ATOMIC_TYPE_LONG)) {
9170                         warningf(WARN_TRADITIONAL, &expr->base.source_position, "'%T' switch expression not converted to '%T' in ISO C", type, type_int);
9171                 }
9172         } else if (is_type_valid(type)) {
9173                 errorf(&expr->base.source_position,
9174                        "switch quantity is not an integer, but '%T'", type);
9175                 type = type_error_type;
9176         }
9177         statement->switchs.expression = create_implicit_cast(expr, type);
9178
9179         switch_statement_t *rem = current_switch;
9180         current_switch          = &statement->switchs;
9181         statement->switchs.body = parse_inner_statement();
9182         current_switch          = rem;
9183
9184         if (statement->switchs.default_label == NULL) {
9185                 warningf(WARN_SWITCH_DEFAULT, &statement->base.source_position, "switch has no default case");
9186         }
9187         check_enum_cases(&statement->switchs);
9188
9189         POP_SCOPE();
9190         POP_PARENT();
9191         return statement;
9192 }
9193
9194 static statement_t *parse_loop_body(statement_t *const loop)
9195 {
9196         statement_t *const rem = current_loop;
9197         current_loop = loop;
9198
9199         statement_t *const body = parse_inner_statement();
9200
9201         current_loop = rem;
9202         return body;
9203 }
9204
9205 /**
9206  * Parse a while statement.
9207  */
9208 static statement_t *parse_while(void)
9209 {
9210         statement_t *statement = allocate_statement_zero(STATEMENT_WHILE);
9211
9212         eat(T_while);
9213
9214         PUSH_PARENT(statement);
9215         PUSH_SCOPE_STATEMENT(&statement->whiles.scope);
9216
9217         expression_t *const cond = parse_condition();
9218         statement->whiles.condition = cond;
9219         /* §6.8.5:2    The controlling expression of an iteration statement shall
9220          *             have scalar type. */
9221         semantic_condition(cond, "condition of 'while'-statement");
9222
9223         statement->whiles.body = parse_loop_body(statement);
9224
9225         POP_SCOPE();
9226         POP_PARENT();
9227         return statement;
9228 }
9229
9230 /**
9231  * Parse a do statement.
9232  */
9233 static statement_t *parse_do(void)
9234 {
9235         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
9236
9237         eat(T_do);
9238
9239         PUSH_PARENT(statement);
9240         PUSH_SCOPE_STATEMENT(&statement->do_while.scope);
9241
9242         add_anchor_token(T_while);
9243         statement->do_while.body = parse_loop_body(statement);
9244         rem_anchor_token(T_while);
9245
9246         expect(T_while);
9247         expression_t *const cond = parse_condition();
9248         statement->do_while.condition = cond;
9249         /* §6.8.5:2    The controlling expression of an iteration statement shall
9250          *             have scalar type. */
9251         semantic_condition(cond, "condition of 'do-while'-statement");
9252         expect(';');
9253
9254         POP_SCOPE();
9255         POP_PARENT();
9256         return statement;
9257 }
9258
9259 /**
9260  * Parse a for statement.
9261  */
9262 static statement_t *parse_for(void)
9263 {
9264         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9265
9266         eat(T_for);
9267
9268         PUSH_PARENT(statement);
9269         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9270
9271         add_anchor_token(')');
9272         expect('(');
9273
9274         PUSH_EXTENSION();
9275
9276         if (next_if(';')) {
9277         } else if (is_declaration_specifier(&token)) {
9278                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9279         } else {
9280                 add_anchor_token(';');
9281                 expression_t *const init = parse_expression();
9282                 statement->fors.initialisation = init;
9283                 mark_vars_read(init, ENT_ANY);
9284                 if (!expression_has_effect(init)) {
9285                         warningf(WARN_UNUSED_VALUE, &init->base.source_position, "initialisation of 'for'-statement has no effect");
9286                 }
9287                 rem_anchor_token(';');
9288                 expect(';');
9289         }
9290
9291         POP_EXTENSION();
9292
9293         if (token.kind != ';') {
9294                 add_anchor_token(';');
9295                 expression_t *const cond = parse_expression();
9296                 statement->fors.condition = cond;
9297                 /* §6.8.5:2    The controlling expression of an iteration statement
9298                  *             shall have scalar type. */
9299                 semantic_condition(cond, "condition of 'for'-statement");
9300                 mark_vars_read(cond, NULL);
9301                 rem_anchor_token(';');
9302         }
9303         expect(';');
9304         if (token.kind != ')') {
9305                 expression_t *const step = parse_expression();
9306                 statement->fors.step = step;
9307                 mark_vars_read(step, ENT_ANY);
9308                 if (!expression_has_effect(step)) {
9309                         warningf(WARN_UNUSED_VALUE, &step->base.source_position, "step of 'for'-statement has no effect");
9310                 }
9311         }
9312         rem_anchor_token(')');
9313         expect(')');
9314         statement->fors.body = parse_loop_body(statement);
9315
9316         POP_SCOPE();
9317         POP_PARENT();
9318         return statement;
9319 }
9320
9321 /**
9322  * Parse a goto statement.
9323  */
9324 static statement_t *parse_goto(void)
9325 {
9326         statement_t *statement;
9327         if (GNU_MODE && look_ahead(1)->kind == '*') {
9328                 statement = allocate_statement_zero(STATEMENT_COMPUTED_GOTO);
9329                 eat(T_goto);
9330                 eat('*');
9331
9332                 expression_t *expression = parse_expression();
9333                 mark_vars_read(expression, NULL);
9334
9335                 /* Argh: although documentation says the expression must be of type void*,
9336                  * gcc accepts anything that can be casted into void* without error */
9337                 type_t *type = expression->base.type;
9338
9339                 if (type != type_error_type) {
9340                         if (!is_type_pointer(type) && !is_type_integer(type)) {
9341                                 errorf(&expression->base.source_position,
9342                                         "cannot convert to a pointer type");
9343                         } else if (type != type_void_ptr) {
9344                                 warningf(WARN_OTHER, &expression->base.source_position, "type of computed goto expression should be 'void*' not '%T'", type);
9345                         }
9346                         expression = create_implicit_cast(expression, type_void_ptr);
9347                 }
9348
9349                 statement->computed_goto.expression = expression;
9350         } else {
9351                 statement = allocate_statement_zero(STATEMENT_GOTO);
9352                 eat(T_goto);
9353
9354                 label_t *const label = get_label("while parsing goto");
9355                 if (label) {
9356                         label->used            = true;
9357                         statement->gotos.label = label;
9358
9359                         /* remember the goto's in a list for later checking */
9360                         *goto_anchor = &statement->gotos;
9361                         goto_anchor  = &statement->gotos.next;
9362                 } else {
9363                         statement->gotos.label = &allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym_anonymous, &builtin_source_position)->label;
9364                 }
9365         }
9366
9367         expect(';');
9368         return statement;
9369 }
9370
9371 /**
9372  * Parse a continue statement.
9373  */
9374 static statement_t *parse_continue(void)
9375 {
9376         if (current_loop == NULL) {
9377                 errorf(HERE, "continue statement not within loop");
9378         }
9379
9380         statement_t *statement = allocate_statement_zero(STATEMENT_CONTINUE);
9381
9382         eat(T_continue);
9383         expect(';');
9384         return statement;
9385 }
9386
9387 /**
9388  * Parse a break statement.
9389  */
9390 static statement_t *parse_break(void)
9391 {
9392         if (current_switch == NULL && current_loop == NULL) {
9393                 errorf(HERE, "break statement not within loop or switch");
9394         }
9395
9396         statement_t *statement = allocate_statement_zero(STATEMENT_BREAK);
9397
9398         eat(T_break);
9399         expect(';');
9400         return statement;
9401 }
9402
9403 /**
9404  * Parse a __leave statement.
9405  */
9406 static statement_t *parse_leave_statement(void)
9407 {
9408         if (current_try == NULL) {
9409                 errorf(HERE, "__leave statement not within __try");
9410         }
9411
9412         statement_t *statement = allocate_statement_zero(STATEMENT_LEAVE);
9413
9414         eat(T___leave);
9415         expect(';');
9416         return statement;
9417 }
9418
9419 /**
9420  * Check if a given entity represents a local variable.
9421  */
9422 static bool is_local_variable(const entity_t *entity)
9423 {
9424         if (entity->kind != ENTITY_VARIABLE)
9425                 return false;
9426
9427         switch ((storage_class_tag_t) entity->declaration.storage_class) {
9428         case STORAGE_CLASS_AUTO:
9429         case STORAGE_CLASS_REGISTER: {
9430                 const type_t *type = skip_typeref(entity->declaration.type);
9431                 if (is_type_function(type)) {
9432                         return false;
9433                 } else {
9434                         return true;
9435                 }
9436         }
9437         default:
9438                 return false;
9439         }
9440 }
9441
9442 /**
9443  * Check if a given expression represents a local variable.
9444  */
9445 static bool expression_is_local_variable(const expression_t *expression)
9446 {
9447         if (expression->base.kind != EXPR_REFERENCE) {
9448                 return false;
9449         }
9450         const entity_t *entity = expression->reference.entity;
9451         return is_local_variable(entity);
9452 }
9453
9454 /**
9455  * Check if a given expression represents a local variable and
9456  * return its declaration then, else return NULL.
9457  */
9458 entity_t *expression_is_variable(const expression_t *expression)
9459 {
9460         if (expression->base.kind != EXPR_REFERENCE) {
9461                 return NULL;
9462         }
9463         entity_t *entity = expression->reference.entity;
9464         if (entity->kind != ENTITY_VARIABLE)
9465                 return NULL;
9466
9467         return entity;
9468 }
9469
9470 static void err_or_warn(source_position_t const *const pos, char const *const msg)
9471 {
9472         if (c_mode & _CXX || strict_mode) {
9473                 errorf(pos, msg);
9474         } else {
9475                 warningf(WARN_OTHER, pos, msg);
9476         }
9477 }
9478
9479 /**
9480  * Parse a return statement.
9481  */
9482 static statement_t *parse_return(void)
9483 {
9484         statement_t *statement = allocate_statement_zero(STATEMENT_RETURN);
9485         eat(T_return);
9486
9487         expression_t *return_value = NULL;
9488         if (token.kind != ';') {
9489                 return_value = parse_expression();
9490                 mark_vars_read(return_value, NULL);
9491         }
9492
9493         const type_t *const func_type = skip_typeref(current_function->base.type);
9494         assert(is_type_function(func_type));
9495         type_t *const return_type = skip_typeref(func_type->function.return_type);
9496
9497         source_position_t const *const pos = &statement->base.source_position;
9498         if (return_value != NULL) {
9499                 type_t *return_value_type = skip_typeref(return_value->base.type);
9500
9501                 if (is_type_void(return_type)) {
9502                         if (!is_type_void(return_value_type)) {
9503                                 /* ISO/IEC 14882:1998(E) §6.6.3:2 */
9504                                 /* Only warn in C mode, because GCC does the same */
9505                                 err_or_warn(pos, "'return' with a value, in function returning 'void'");
9506                         } else if (!(c_mode & _CXX)) { /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9507                                 /* Only warn in C mode, because GCC does the same */
9508                                 err_or_warn(pos, "'return' with expression in function returning 'void'");
9509                         }
9510                 } else {
9511                         assign_error_t error = semantic_assign(return_type, return_value);
9512                         report_assign_error(error, return_type, return_value, "'return'",
9513                                             pos);
9514                 }
9515                 return_value = create_implicit_cast(return_value, return_type);
9516                 /* check for returning address of a local var */
9517                 if (return_value != NULL && return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
9518                         const expression_t *expression = return_value->unary.value;
9519                         if (expression_is_local_variable(expression)) {
9520                                 warningf(WARN_OTHER, pos, "function returns address of local variable");
9521                         }
9522                 }
9523         } else if (!is_type_void(return_type)) {
9524                 /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9525                 err_or_warn(pos, "'return' without value, in function returning non-void");
9526         }
9527         statement->returns.value = return_value;
9528
9529         expect(';');
9530         return statement;
9531 }
9532
9533 /**
9534  * Parse a declaration statement.
9535  */
9536 static statement_t *parse_declaration_statement(void)
9537 {
9538         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9539
9540         entity_t *before = current_scope->last_entity;
9541         if (GNU_MODE) {
9542                 parse_external_declaration();
9543         } else {
9544                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9545         }
9546
9547         declaration_statement_t *const decl  = &statement->declaration;
9548         entity_t                *const begin =
9549                 before != NULL ? before->base.next : current_scope->entities;
9550         decl->declarations_begin = begin;
9551         decl->declarations_end   = begin != NULL ? current_scope->last_entity : NULL;
9552
9553         return statement;
9554 }
9555
9556 /**
9557  * Parse an expression statement, ie. expr ';'.
9558  */
9559 static statement_t *parse_expression_statement(void)
9560 {
9561         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
9562
9563         expression_t *const expr         = parse_expression();
9564         statement->expression.expression = expr;
9565         mark_vars_read(expr, ENT_ANY);
9566
9567         expect(';');
9568         return statement;
9569 }
9570
9571 /**
9572  * Parse a microsoft __try { } __finally { } or
9573  * __try{ } __except() { }
9574  */
9575 static statement_t *parse_ms_try_statment(void)
9576 {
9577         statement_t *statement = allocate_statement_zero(STATEMENT_MS_TRY);
9578         eat(T___try);
9579
9580         PUSH_PARENT(statement);
9581
9582         ms_try_statement_t *rem = current_try;
9583         current_try = &statement->ms_try;
9584         statement->ms_try.try_statement = parse_compound_statement(false);
9585         current_try = rem;
9586
9587         POP_PARENT();
9588
9589         if (next_if(T___except)) {
9590                 expression_t *const expr = parse_condition();
9591                 type_t       *      type = skip_typeref(expr->base.type);
9592                 if (is_type_integer(type)) {
9593                         type = promote_integer(type);
9594                 } else if (is_type_valid(type)) {
9595                         errorf(&expr->base.source_position,
9596                                "__expect expression is not an integer, but '%T'", type);
9597                         type = type_error_type;
9598                 }
9599                 statement->ms_try.except_expression = create_implicit_cast(expr, type);
9600         } else if (!next_if(T__finally)) {
9601                 parse_error_expected("while parsing __try statement", T___except, T___finally, NULL);
9602         }
9603         statement->ms_try.final_statement = parse_compound_statement(false);
9604         return statement;
9605 }
9606
9607 static statement_t *parse_empty_statement(void)
9608 {
9609         warningf(WARN_EMPTY_STATEMENT, HERE, "statement is empty");
9610         statement_t *const statement = create_empty_statement();
9611         eat(';');
9612         return statement;
9613 }
9614
9615 static statement_t *parse_local_label_declaration(void)
9616 {
9617         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9618
9619         eat(T___label__);
9620
9621         entity_t *begin   = NULL;
9622         entity_t *end     = NULL;
9623         entity_t **anchor = &begin;
9624         add_anchor_token(';');
9625         add_anchor_token(',');
9626         do {
9627                 source_position_t pos;
9628                 symbol_t *const symbol = expect_identifier("while parsing local label declaration", &pos);
9629                 if (symbol) {
9630                         entity_t *entity = get_entity(symbol, NAMESPACE_LABEL);
9631                         if (entity != NULL && entity->base.parent_scope == current_scope) {
9632                                 source_position_t const *const ppos = &entity->base.source_position;
9633                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
9634                         } else {
9635                                 entity = allocate_entity_zero(ENTITY_LOCAL_LABEL, NAMESPACE_LABEL, symbol, &pos);
9636                                 entity->base.parent_scope = current_scope;
9637
9638                                 *anchor = entity;
9639                                 anchor  = &entity->base.next;
9640                                 end     = entity;
9641
9642                                 environment_push(entity);
9643                         }
9644                 }
9645         } while (next_if(','));
9646         rem_anchor_token(',');
9647         rem_anchor_token(';');
9648         expect(';');
9649         statement->declaration.declarations_begin = begin;
9650         statement->declaration.declarations_end   = end;
9651         return statement;
9652 }
9653
9654 static void parse_namespace_definition(void)
9655 {
9656         eat(T_namespace);
9657
9658         entity_t *entity = NULL;
9659         symbol_t *symbol = NULL;
9660
9661         if (token.kind == T_IDENTIFIER) {
9662                 symbol = token.base.symbol;
9663                 entity = get_entity(symbol, NAMESPACE_NORMAL);
9664                 if (entity && entity->kind != ENTITY_NAMESPACE) {
9665                         entity = NULL;
9666                         if (entity->base.parent_scope == current_scope && is_entity_valid(entity)) {
9667                                 error_redefined_as_different_kind(HERE, entity, ENTITY_NAMESPACE);
9668                         }
9669                 }
9670                 eat(T_IDENTIFIER);
9671         }
9672
9673         if (entity == NULL) {
9674                 entity = allocate_entity_zero(ENTITY_NAMESPACE, NAMESPACE_NORMAL, symbol, HERE);
9675                 entity->base.parent_scope = current_scope;
9676         }
9677
9678         if (token.kind == '=') {
9679                 /* TODO: parse namespace alias */
9680                 panic("namespace alias definition not supported yet");
9681         }
9682
9683         environment_push(entity);
9684         append_entity(current_scope, entity);
9685
9686         PUSH_SCOPE(&entity->namespacee.members);
9687         PUSH_CURRENT_ENTITY(entity);
9688
9689         add_anchor_token('}');
9690         expect('{');
9691         parse_externals();
9692         rem_anchor_token('}');
9693         expect('}');
9694
9695         POP_CURRENT_ENTITY();
9696         POP_SCOPE();
9697 }
9698
9699 /**
9700  * Parse a statement.
9701  * There's also parse_statement() which additionally checks for
9702  * "statement has no effect" warnings
9703  */
9704 static statement_t *intern_parse_statement(void)
9705 {
9706         /* declaration or statement */
9707         statement_t *statement;
9708         switch (token.kind) {
9709         case T_IDENTIFIER: {
9710                 token_kind_t la1_type = (token_kind_t)look_ahead(1)->kind;
9711                 if (la1_type == ':') {
9712                         statement = parse_label_statement();
9713                 } else if (is_typedef_symbol(token.base.symbol)) {
9714                         statement = parse_declaration_statement();
9715                 } else {
9716                         /* it's an identifier, the grammar says this must be an
9717                          * expression statement. However it is common that users mistype
9718                          * declaration types, so we guess a bit here to improve robustness
9719                          * for incorrect programs */
9720                         switch (la1_type) {
9721                         case '&':
9722                         case '*':
9723                                 if (get_entity(token.base.symbol, NAMESPACE_NORMAL) != NULL) {
9724                         default:
9725                                         statement = parse_expression_statement();
9726                                 } else {
9727                         DECLARATION_START
9728                         case T_IDENTIFIER:
9729                                         statement = parse_declaration_statement();
9730                                 }
9731                                 break;
9732                         }
9733                 }
9734                 break;
9735         }
9736
9737         case T___extension__: {
9738                 /* This can be a prefix to a declaration or an expression statement.
9739                  * We simply eat it now and parse the rest with tail recursion. */
9740                 PUSH_EXTENSION();
9741                 statement = intern_parse_statement();
9742                 POP_EXTENSION();
9743                 break;
9744         }
9745
9746         DECLARATION_START
9747                 statement = parse_declaration_statement();
9748                 break;
9749
9750         case T___label__:
9751                 statement = parse_local_label_declaration();
9752                 break;
9753
9754         case ';':         statement = parse_empty_statement();         break;
9755         case '{':         statement = parse_compound_statement(false); break;
9756         case T___leave:   statement = parse_leave_statement();         break;
9757         case T___try:     statement = parse_ms_try_statment();         break;
9758         case T_asm:       statement = parse_asm_statement();           break;
9759         case T_break:     statement = parse_break();                   break;
9760         case T_case:      statement = parse_case_statement();          break;
9761         case T_continue:  statement = parse_continue();                break;
9762         case T_default:   statement = parse_default_statement();       break;
9763         case T_do:        statement = parse_do();                      break;
9764         case T_for:       statement = parse_for();                     break;
9765         case T_goto:      statement = parse_goto();                    break;
9766         case T_if:        statement = parse_if();                      break;
9767         case T_return:    statement = parse_return();                  break;
9768         case T_switch:    statement = parse_switch();                  break;
9769         case T_while:     statement = parse_while();                   break;
9770
9771         EXPRESSION_START
9772                 statement = parse_expression_statement();
9773                 break;
9774
9775         default:
9776                 errorf(HERE, "unexpected token %K while parsing statement", &token);
9777                 statement = create_error_statement();
9778                 eat_until_anchor();
9779                 break;
9780         }
9781
9782         return statement;
9783 }
9784
9785 /**
9786  * parse a statement and emits "statement has no effect" warning if needed
9787  * (This is really a wrapper around intern_parse_statement with check for 1
9788  *  single warning. It is needed, because for statement expressions we have
9789  *  to avoid the warning on the last statement)
9790  */
9791 static statement_t *parse_statement(void)
9792 {
9793         statement_t *statement = intern_parse_statement();
9794
9795         if (statement->kind == STATEMENT_EXPRESSION) {
9796                 expression_t *expression = statement->expression.expression;
9797                 if (!expression_has_effect(expression)) {
9798                         warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9799                 }
9800         }
9801
9802         return statement;
9803 }
9804
9805 /**
9806  * Parse a compound statement.
9807  */
9808 static statement_t *parse_compound_statement(bool inside_expression_statement)
9809 {
9810         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
9811
9812         PUSH_PARENT(statement);
9813         PUSH_SCOPE(&statement->compound.scope);
9814
9815         eat('{');
9816         add_anchor_token('}');
9817         /* tokens, which can start a statement */
9818         /* TODO MS, __builtin_FOO */
9819         add_anchor_token('!');
9820         add_anchor_token('&');
9821         add_anchor_token('(');
9822         add_anchor_token('*');
9823         add_anchor_token('+');
9824         add_anchor_token('-');
9825         add_anchor_token(';');
9826         add_anchor_token('{');
9827         add_anchor_token('~');
9828         add_anchor_token(T_CHARACTER_CONSTANT);
9829         add_anchor_token(T_COLONCOLON);
9830         add_anchor_token(T_FLOATINGPOINT);
9831         add_anchor_token(T_IDENTIFIER);
9832         add_anchor_token(T_INTEGER);
9833         add_anchor_token(T_MINUSMINUS);
9834         add_anchor_token(T_PLUSPLUS);
9835         add_anchor_token(T_STRING_LITERAL);
9836         add_anchor_token(T_WIDE_CHARACTER_CONSTANT);
9837         add_anchor_token(T__Bool);
9838         add_anchor_token(T__Complex);
9839         add_anchor_token(T__Imaginary);
9840         add_anchor_token(T___FUNCTION__);
9841         add_anchor_token(T___PRETTY_FUNCTION__);
9842         add_anchor_token(T___alignof__);
9843         add_anchor_token(T___attribute__);
9844         add_anchor_token(T___builtin_va_start);
9845         add_anchor_token(T___extension__);
9846         add_anchor_token(T___func__);
9847         add_anchor_token(T___imag__);
9848         add_anchor_token(T___label__);
9849         add_anchor_token(T___real__);
9850         add_anchor_token(T___thread);
9851         add_anchor_token(T_asm);
9852         add_anchor_token(T_auto);
9853         add_anchor_token(T_bool);
9854         add_anchor_token(T_break);
9855         add_anchor_token(T_case);
9856         add_anchor_token(T_char);
9857         add_anchor_token(T_class);
9858         add_anchor_token(T_const);
9859         add_anchor_token(T_const_cast);
9860         add_anchor_token(T_continue);
9861         add_anchor_token(T_default);
9862         add_anchor_token(T_delete);
9863         add_anchor_token(T_double);
9864         add_anchor_token(T_do);
9865         add_anchor_token(T_dynamic_cast);
9866         add_anchor_token(T_enum);
9867         add_anchor_token(T_extern);
9868         add_anchor_token(T_false);
9869         add_anchor_token(T_float);
9870         add_anchor_token(T_for);
9871         add_anchor_token(T_goto);
9872         add_anchor_token(T_if);
9873         add_anchor_token(T_inline);
9874         add_anchor_token(T_int);
9875         add_anchor_token(T_long);
9876         add_anchor_token(T_new);
9877         add_anchor_token(T_operator);
9878         add_anchor_token(T_register);
9879         add_anchor_token(T_reinterpret_cast);
9880         add_anchor_token(T_restrict);
9881         add_anchor_token(T_return);
9882         add_anchor_token(T_short);
9883         add_anchor_token(T_signed);
9884         add_anchor_token(T_sizeof);
9885         add_anchor_token(T_static);
9886         add_anchor_token(T_static_cast);
9887         add_anchor_token(T_struct);
9888         add_anchor_token(T_switch);
9889         add_anchor_token(T_template);
9890         add_anchor_token(T_this);
9891         add_anchor_token(T_throw);
9892         add_anchor_token(T_true);
9893         add_anchor_token(T_try);
9894         add_anchor_token(T_typedef);
9895         add_anchor_token(T_typeid);
9896         add_anchor_token(T_typename);
9897         add_anchor_token(T_typeof);
9898         add_anchor_token(T_union);
9899         add_anchor_token(T_unsigned);
9900         add_anchor_token(T_using);
9901         add_anchor_token(T_void);
9902         add_anchor_token(T_volatile);
9903         add_anchor_token(T_wchar_t);
9904         add_anchor_token(T_while);
9905
9906         statement_t **anchor            = &statement->compound.statements;
9907         bool          only_decls_so_far = true;
9908         while (token.kind != '}' && token.kind != T_EOF) {
9909                 statement_t *sub_statement = intern_parse_statement();
9910                 if (sub_statement->kind == STATEMENT_ERROR) {
9911                         break;
9912                 }
9913
9914                 if (sub_statement->kind != STATEMENT_DECLARATION) {
9915                         only_decls_so_far = false;
9916                 } else if (!only_decls_so_far) {
9917                         source_position_t const *const pos = &sub_statement->base.source_position;
9918                         warningf(WARN_DECLARATION_AFTER_STATEMENT, pos, "ISO C90 forbids mixed declarations and code");
9919                 }
9920
9921                 *anchor = sub_statement;
9922                 anchor  = &sub_statement->base.next;
9923         }
9924         expect('}');
9925
9926         /* look over all statements again to produce no effect warnings */
9927         if (is_warn_on(WARN_UNUSED_VALUE)) {
9928                 statement_t *sub_statement = statement->compound.statements;
9929                 for (; sub_statement != NULL; sub_statement = sub_statement->base.next) {
9930                         if (sub_statement->kind != STATEMENT_EXPRESSION)
9931                                 continue;
9932                         /* don't emit a warning for the last expression in an expression
9933                          * statement as it has always an effect */
9934                         if (inside_expression_statement && sub_statement->base.next == NULL)
9935                                 continue;
9936
9937                         expression_t *expression = sub_statement->expression.expression;
9938                         if (!expression_has_effect(expression)) {
9939                                 warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9940                         }
9941                 }
9942         }
9943
9944         rem_anchor_token(T_while);
9945         rem_anchor_token(T_wchar_t);
9946         rem_anchor_token(T_volatile);
9947         rem_anchor_token(T_void);
9948         rem_anchor_token(T_using);
9949         rem_anchor_token(T_unsigned);
9950         rem_anchor_token(T_union);
9951         rem_anchor_token(T_typeof);
9952         rem_anchor_token(T_typename);
9953         rem_anchor_token(T_typeid);
9954         rem_anchor_token(T_typedef);
9955         rem_anchor_token(T_try);
9956         rem_anchor_token(T_true);
9957         rem_anchor_token(T_throw);
9958         rem_anchor_token(T_this);
9959         rem_anchor_token(T_template);
9960         rem_anchor_token(T_switch);
9961         rem_anchor_token(T_struct);
9962         rem_anchor_token(T_static_cast);
9963         rem_anchor_token(T_static);
9964         rem_anchor_token(T_sizeof);
9965         rem_anchor_token(T_signed);
9966         rem_anchor_token(T_short);
9967         rem_anchor_token(T_return);
9968         rem_anchor_token(T_restrict);
9969         rem_anchor_token(T_reinterpret_cast);
9970         rem_anchor_token(T_register);
9971         rem_anchor_token(T_operator);
9972         rem_anchor_token(T_new);
9973         rem_anchor_token(T_long);
9974         rem_anchor_token(T_int);
9975         rem_anchor_token(T_inline);
9976         rem_anchor_token(T_if);
9977         rem_anchor_token(T_goto);
9978         rem_anchor_token(T_for);
9979         rem_anchor_token(T_float);
9980         rem_anchor_token(T_false);
9981         rem_anchor_token(T_extern);
9982         rem_anchor_token(T_enum);
9983         rem_anchor_token(T_dynamic_cast);
9984         rem_anchor_token(T_do);
9985         rem_anchor_token(T_double);
9986         rem_anchor_token(T_delete);
9987         rem_anchor_token(T_default);
9988         rem_anchor_token(T_continue);
9989         rem_anchor_token(T_const_cast);
9990         rem_anchor_token(T_const);
9991         rem_anchor_token(T_class);
9992         rem_anchor_token(T_char);
9993         rem_anchor_token(T_case);
9994         rem_anchor_token(T_break);
9995         rem_anchor_token(T_bool);
9996         rem_anchor_token(T_auto);
9997         rem_anchor_token(T_asm);
9998         rem_anchor_token(T___thread);
9999         rem_anchor_token(T___real__);
10000         rem_anchor_token(T___label__);
10001         rem_anchor_token(T___imag__);
10002         rem_anchor_token(T___func__);
10003         rem_anchor_token(T___extension__);
10004         rem_anchor_token(T___builtin_va_start);
10005         rem_anchor_token(T___attribute__);
10006         rem_anchor_token(T___alignof__);
10007         rem_anchor_token(T___PRETTY_FUNCTION__);
10008         rem_anchor_token(T___FUNCTION__);
10009         rem_anchor_token(T__Imaginary);
10010         rem_anchor_token(T__Complex);
10011         rem_anchor_token(T__Bool);
10012         rem_anchor_token(T_WIDE_CHARACTER_CONSTANT);
10013         rem_anchor_token(T_STRING_LITERAL);
10014         rem_anchor_token(T_PLUSPLUS);
10015         rem_anchor_token(T_MINUSMINUS);
10016         rem_anchor_token(T_INTEGER);
10017         rem_anchor_token(T_IDENTIFIER);
10018         rem_anchor_token(T_FLOATINGPOINT);
10019         rem_anchor_token(T_COLONCOLON);
10020         rem_anchor_token(T_CHARACTER_CONSTANT);
10021         rem_anchor_token('~');
10022         rem_anchor_token('{');
10023         rem_anchor_token(';');
10024         rem_anchor_token('-');
10025         rem_anchor_token('+');
10026         rem_anchor_token('*');
10027         rem_anchor_token('(');
10028         rem_anchor_token('&');
10029         rem_anchor_token('!');
10030         rem_anchor_token('}');
10031
10032         POP_SCOPE();
10033         POP_PARENT();
10034         return statement;
10035 }
10036
10037 /**
10038  * Check for unused global static functions and variables
10039  */
10040 static void check_unused_globals(void)
10041 {
10042         if (!is_warn_on(WARN_UNUSED_FUNCTION) && !is_warn_on(WARN_UNUSED_VARIABLE))
10043                 return;
10044
10045         for (const entity_t *entity = file_scope->entities; entity != NULL;
10046              entity = entity->base.next) {
10047                 if (!is_declaration(entity))
10048                         continue;
10049
10050                 const declaration_t *declaration = &entity->declaration;
10051                 if (declaration->used                  ||
10052                     declaration->modifiers & DM_UNUSED ||
10053                     declaration->modifiers & DM_USED   ||
10054                     declaration->storage_class != STORAGE_CLASS_STATIC)
10055                         continue;
10056
10057                 warning_t   why;
10058                 char const *s;
10059                 if (entity->kind == ENTITY_FUNCTION) {
10060                         /* inhibit warning for static inline functions */
10061                         if (entity->function.is_inline)
10062                                 continue;
10063
10064                         why = WARN_UNUSED_FUNCTION;
10065                         s   = entity->function.statement != NULL ? "defined" : "declared";
10066                 } else {
10067                         why = WARN_UNUSED_VARIABLE;
10068                         s   = "defined";
10069                 }
10070
10071                 warningf(why, &declaration->base.source_position, "'%#N' %s but not used", entity, s);
10072         }
10073 }
10074
10075 static void parse_global_asm(void)
10076 {
10077         statement_t *statement = allocate_statement_zero(STATEMENT_ASM);
10078
10079         eat(T_asm);
10080         add_anchor_token(';');
10081         add_anchor_token(')');
10082         add_anchor_token(T_STRING_LITERAL);
10083         expect('(');
10084
10085         rem_anchor_token(T_STRING_LITERAL);
10086         statement->asms.asm_text = parse_string_literals();
10087         statement->base.next     = unit->global_asm;
10088         unit->global_asm         = statement;
10089
10090         rem_anchor_token(')');
10091         expect(')');
10092         rem_anchor_token(';');
10093         expect(';');
10094 }
10095
10096 static void parse_linkage_specification(void)
10097 {
10098         eat(T_extern);
10099
10100         source_position_t const pos     = *HERE;
10101         char const       *const linkage = parse_string_literals().begin;
10102
10103         linkage_kind_t old_linkage = current_linkage;
10104         linkage_kind_t new_linkage;
10105         if (streq(linkage, "C")) {
10106                 new_linkage = LINKAGE_C;
10107         } else if (streq(linkage, "C++")) {
10108                 new_linkage = LINKAGE_CXX;
10109         } else {
10110                 errorf(&pos, "linkage string \"%s\" not recognized", linkage);
10111                 new_linkage = LINKAGE_C;
10112         }
10113         current_linkage = new_linkage;
10114
10115         if (next_if('{')) {
10116                 parse_externals();
10117                 expect('}');
10118         } else {
10119                 parse_external();
10120         }
10121
10122         assert(current_linkage == new_linkage);
10123         current_linkage = old_linkage;
10124 }
10125
10126 static void parse_external(void)
10127 {
10128         switch (token.kind) {
10129                 case T_extern:
10130                         if (look_ahead(1)->kind == T_STRING_LITERAL) {
10131                                 parse_linkage_specification();
10132                         } else {
10133                 DECLARATION_START_NO_EXTERN
10134                 case T_IDENTIFIER:
10135                 case T___extension__:
10136                 /* tokens below are for implicit int */
10137                 case '&':  /* & x; -> int& x; (and error later, because C++ has no
10138                               implicit int) */
10139                 case '*':  /* * x; -> int* x; */
10140                 case '(':  /* (x); -> int (x); */
10141                                 PUSH_EXTENSION();
10142                                 parse_external_declaration();
10143                                 POP_EXTENSION();
10144                         }
10145                         return;
10146
10147                 case T_asm:
10148                         parse_global_asm();
10149                         return;
10150
10151                 case T_namespace:
10152                         parse_namespace_definition();
10153                         return;
10154
10155                 case ';':
10156                         if (!strict_mode) {
10157                                 warningf(WARN_STRAY_SEMICOLON, HERE, "stray ';' outside of function");
10158                                 eat(';');
10159                                 return;
10160                         }
10161                         /* FALLTHROUGH */
10162
10163                 default:
10164                         errorf(HERE, "stray %K outside of function", &token);
10165                         if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10166                                 eat_until_matching_token(token.kind);
10167                         next_token();
10168                         return;
10169         }
10170 }
10171
10172 static void parse_externals(void)
10173 {
10174         add_anchor_token('}');
10175         add_anchor_token(T_EOF);
10176
10177 #ifndef NDEBUG
10178         /* make a copy of the anchor set, so we can check if it is restored after parsing */
10179         unsigned short token_anchor_copy[T_LAST_TOKEN];
10180         memcpy(token_anchor_copy, token_anchor_set, sizeof(token_anchor_copy));
10181 #endif
10182
10183         while (token.kind != T_EOF && token.kind != '}') {
10184 #ifndef NDEBUG
10185                 for (int i = 0; i < T_LAST_TOKEN; ++i) {
10186                         unsigned short count = token_anchor_set[i] - token_anchor_copy[i];
10187                         if (count != 0) {
10188                                 /* the anchor set and its copy differs */
10189                                 internal_errorf(HERE, "Leaked anchor token %k %d times", i, count);
10190                         }
10191                 }
10192                 if (in_gcc_extension) {
10193                         /* an gcc extension scope was not closed */
10194                         internal_errorf(HERE, "Leaked __extension__");
10195                 }
10196 #endif
10197
10198                 parse_external();
10199         }
10200
10201         rem_anchor_token(T_EOF);
10202         rem_anchor_token('}');
10203 }
10204
10205 /**
10206  * Parse a translation unit.
10207  */
10208 static void parse_translation_unit(void)
10209 {
10210         add_anchor_token(T_EOF);
10211
10212         while (true) {
10213                 parse_externals();
10214
10215                 if (token.kind == T_EOF)
10216                         break;
10217
10218                 errorf(HERE, "stray %K outside of function", &token);
10219                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10220                         eat_until_matching_token(token.kind);
10221                 next_token();
10222         }
10223 }
10224
10225 void set_default_visibility(elf_visibility_tag_t visibility)
10226 {
10227         default_visibility = visibility;
10228 }
10229
10230 /**
10231  * Parse the input.
10232  *
10233  * @return  the translation unit or NULL if errors occurred.
10234  */
10235 void start_parsing(void)
10236 {
10237         environment_stack = NEW_ARR_F(stack_entry_t, 0);
10238         label_stack       = NEW_ARR_F(stack_entry_t, 0);
10239         diagnostic_count  = 0;
10240         error_count       = 0;
10241         warning_count     = 0;
10242
10243         print_to_file(stderr);
10244
10245         assert(unit == NULL);
10246         unit = allocate_ast_zero(sizeof(unit[0]));
10247
10248         assert(file_scope == NULL);
10249         file_scope = &unit->scope;
10250
10251         assert(current_scope == NULL);
10252         scope_push(&unit->scope);
10253
10254         create_gnu_builtins();
10255         if (c_mode & _MS)
10256                 create_microsoft_intrinsics();
10257 }
10258
10259 translation_unit_t *finish_parsing(void)
10260 {
10261         assert(current_scope == &unit->scope);
10262         scope_pop(NULL);
10263
10264         assert(file_scope == &unit->scope);
10265         check_unused_globals();
10266         file_scope = NULL;
10267
10268         DEL_ARR_F(environment_stack);
10269         DEL_ARR_F(label_stack);
10270
10271         translation_unit_t *result = unit;
10272         unit = NULL;
10273         return result;
10274 }
10275
10276 /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
10277  * are given length one. */
10278 static void complete_incomplete_arrays(void)
10279 {
10280         size_t n = ARR_LEN(incomplete_arrays);
10281         for (size_t i = 0; i != n; ++i) {
10282                 declaration_t *const decl = incomplete_arrays[i];
10283                 type_t        *const type = skip_typeref(decl->type);
10284
10285                 if (!is_type_incomplete(type))
10286                         continue;
10287
10288                 source_position_t const *const pos = &decl->base.source_position;
10289                 warningf(WARN_OTHER, pos, "array '%#N' assumed to have one element", (entity_t const*)decl);
10290
10291                 type_t *const new_type = duplicate_type(type);
10292                 new_type->array.size_constant     = true;
10293                 new_type->array.has_implicit_size = true;
10294                 new_type->array.size              = 1;
10295
10296                 type_t *const result = identify_new_type(new_type);
10297
10298                 decl->type = result;
10299         }
10300 }
10301
10302 static void prepare_main_collect2(entity_t *const entity)
10303 {
10304         PUSH_SCOPE(&entity->function.statement->compound.scope);
10305
10306         // create call to __main
10307         symbol_t *symbol         = symbol_table_insert("__main");
10308         entity_t *subsubmain_ent
10309                 = create_implicit_function(symbol, &builtin_source_position);
10310
10311         expression_t *ref         = allocate_expression_zero(EXPR_REFERENCE);
10312         type_t       *ftype       = subsubmain_ent->declaration.type;
10313         ref->base.source_position = builtin_source_position;
10314         ref->base.type            = make_pointer_type(ftype, TYPE_QUALIFIER_NONE);
10315         ref->reference.entity     = subsubmain_ent;
10316
10317         expression_t *call = allocate_expression_zero(EXPR_CALL);
10318         call->base.source_position = builtin_source_position;
10319         call->base.type            = type_void;
10320         call->call.function        = ref;
10321
10322         statement_t *expr_statement = allocate_statement_zero(STATEMENT_EXPRESSION);
10323         expr_statement->base.source_position  = builtin_source_position;
10324         expr_statement->expression.expression = call;
10325
10326         statement_t *statement = entity->function.statement;
10327         assert(statement->kind == STATEMENT_COMPOUND);
10328         compound_statement_t *compounds = &statement->compound;
10329
10330         expr_statement->base.next = compounds->statements;
10331         compounds->statements     = expr_statement;
10332
10333         POP_SCOPE();
10334 }
10335
10336 void parse(void)
10337 {
10338         lookahead_bufpos = 0;
10339         for (int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
10340                 next_token();
10341         }
10342         current_linkage   = c_mode & _CXX ? LINKAGE_CXX : LINKAGE_C;
10343         incomplete_arrays = NEW_ARR_F(declaration_t*, 0);
10344         parse_translation_unit();
10345         complete_incomplete_arrays();
10346         DEL_ARR_F(incomplete_arrays);
10347         incomplete_arrays = NULL;
10348 }
10349
10350 /**
10351  * Initialize the parser.
10352  */
10353 void init_parser(void)
10354 {
10355         sym_anonymous = symbol_table_insert("<anonymous>");
10356
10357         memset(token_anchor_set, 0, sizeof(token_anchor_set));
10358
10359         init_expression_parsers();
10360         obstack_init(&temp_obst);
10361 }
10362
10363 /**
10364  * Terminate the parser.
10365  */
10366 void exit_parser(void)
10367 {
10368         obstack_free(&temp_obst, NULL);
10369 }