nsz Git - cparser/blob - parser.c

   1 #include <config.h>
   2
   3 #include <assert.h>
   4 #include <stdarg.h>
   5 #include <stdbool.h>
   6
   7 #include "diagnostic.h"
   8 #include "format_check.h"
   9 #include "parser.h"
  10 #include "lexer.h"
  11 #include "token_t.h"
  12 #include "types.h"
  13 #include "type_t.h"
  14 #include "type_hash.h"
  15 #include "ast_t.h"
  16 #include "lang_features.h"
  17 #include "warning.h"
  18 #include "adt/bitfiddle.h"
  19 #include "adt/error.h"
  20 #include "adt/array.h"
  21
  22 //#define PRINT_TOKENS
  23 #define MAX_LOOKAHEAD 2
  24
  25 typedef struct {
  26         declaration_t *old_declaration;
  27         symbol_t      *symbol;
  28         unsigned short namespc;
  29 } stack_entry_t;
  30
  31 typedef struct declaration_specifiers_t  declaration_specifiers_t;
  32 struct declaration_specifiers_t {
  33         source_position_t  source_position;
  34         unsigned char      declared_storage_class;
  35         bool               is_inline;
  36         decl_modifiers_t   decl_modifiers;
  37         type_t            *type;
  38 };
  39
  40 typedef declaration_t* (*parsed_declaration_func) (declaration_t *declaration);
  41
  42 static token_t             token;
  43 static token_t             lookahead_buffer[MAX_LOOKAHEAD];
  44 static int                 lookahead_bufpos;
  45 static stack_entry_t      *environment_stack = NULL;
  46 static stack_entry_t      *label_stack       = NULL;
  47 static scope_t            *global_scope      = NULL;
  48 static scope_t            *scope             = NULL;
  49 static declaration_t      *last_declaration  = NULL;
  50 static declaration_t      *current_function  = NULL;
  51 static switch_statement_t *current_switch    = NULL;
  52 static statement_t        *current_loop      = NULL;
  53 static goto_statement_t   *goto_first        = NULL;
  54 static goto_statement_t   *goto_last         = NULL;
  55 static label_statement_t  *label_first       = NULL;
  56 static label_statement_t  *label_last        = NULL;
  57 static struct obstack      temp_obst;
  58
  59 /** The current source position. */
  60 #define HERE token.source_position
  61
  62 static type_t *type_valist;
  63
  64 static statement_t *parse_compound_statement(void);
  65 static statement_t *parse_statement(void);
  66
  67 static expression_t *parse_sub_expression(unsigned precedence);
  68 static expression_t *parse_expression(void);
  69 static type_t       *parse_typename(void);
  70
  71 static void parse_compound_type_entries(declaration_t *compound_declaration);
  72 static declaration_t *parse_declarator(
  73                 const declaration_specifiers_t *specifiers, bool may_be_abstract);
  74 static declaration_t *record_declaration(declaration_t *declaration);
  75
  76 static void semantic_comparison(binary_expression_t *expression);
  77
  78 #define STORAGE_CLASSES     \
  79         case T_typedef:         \
  80         case T_extern:          \
  81         case T_static:          \
  82         case T_auto:            \
  83         case T_register:
  84
  85 #define TYPE_QUALIFIERS     \
  86         case T_const:           \
  87         case T_restrict:        \
  88         case T_volatile:        \
  89         case T_inline:          \
  90         case T_forceinline:
  91
  92 #ifdef PROVIDE_COMPLEX
  93 #define COMPLEX_SPECIFIERS  \
  94         case T__Complex:
  95 #define IMAGINARY_SPECIFIERS \
  96         case T__Imaginary:
  97 #else
  98 #define COMPLEX_SPECIFIERS
  99 #define IMAGINARY_SPECIFIERS
 100 #endif
 101
 102 #define TYPE_SPECIFIERS       \
 103         case T_void:              \
 104         case T_char:              \
 105         case T_short:             \
 106         case T_int:               \
 107         case T_long:              \
 108         case T_float:             \
 109         case T_double:            \
 110         case T_signed:            \
 111         case T_unsigned:          \
 112         case T__Bool:             \
 113         case T_struct:            \
 114         case T_union:             \
 115         case T_enum:              \
 116         case T___typeof__:        \
 117         case T___builtin_va_list: \
 118         COMPLEX_SPECIFIERS        \
 119         IMAGINARY_SPECIFIERS
 120
 121 #define DECLARATION_START   \
 122         STORAGE_CLASSES         \
 123         TYPE_QUALIFIERS         \
 124         TYPE_SPECIFIERS
 125
 126 #define TYPENAME_START      \
 127         TYPE_QUALIFIERS         \
 128         TYPE_SPECIFIERS
 129
 130 /**
 131  * Allocate an AST node with given size and
 132  * initialize all fields with zero.
 133  */
 134 static void *allocate_ast_zero(size_t size)
 135 {
 136         void *res = allocate_ast(size);
 137         memset(res, 0, size);
 138         return res;
 139 }
 140
 141 static declaration_t *allocate_declaration_zero(void)
 142 {
 143         declaration_t *declaration = allocate_ast_zero(sizeof(declaration_t));
 144         declaration->type = type_error_type;
 145         return declaration;
 146 }
 147
 148 /**
 149  * Returns the size of a statement node.
 150  *
 151  * @param kind  the statement kind
 152  */
 153 static size_t get_statement_struct_size(statement_kind_t kind)
 154 {
 155         static const size_t sizes[] = {
 156                 [STATEMENT_COMPOUND]    = sizeof(compound_statement_t),
 157                 [STATEMENT_RETURN]      = sizeof(return_statement_t),
 158                 [STATEMENT_DECLARATION] = sizeof(declaration_statement_t),
 159                 [STATEMENT_IF]          = sizeof(if_statement_t),
 160                 [STATEMENT_SWITCH]      = sizeof(switch_statement_t),
 161                 [STATEMENT_EXPRESSION]  = sizeof(expression_statement_t),
 162                 [STATEMENT_CONTINUE]    = sizeof(statement_base_t),
 163                 [STATEMENT_BREAK]       = sizeof(statement_base_t),
 164                 [STATEMENT_GOTO]        = sizeof(goto_statement_t),
 165                 [STATEMENT_LABEL]       = sizeof(label_statement_t),
 166                 [STATEMENT_CASE_LABEL]  = sizeof(case_label_statement_t),
 167                 [STATEMENT_WHILE]       = sizeof(while_statement_t),
 168                 [STATEMENT_DO_WHILE]    = sizeof(do_while_statement_t),
 169                 [STATEMENT_FOR]         = sizeof(for_statement_t),
 170                 [STATEMENT_ASM]         = sizeof(asm_statement_t)
 171         };
 172         assert(kind <= sizeof(sizes) / sizeof(sizes[0]));
 173         assert(sizes[kind] != 0);
 174         return sizes[kind];
 175 }
 176
 177 /**
 178  * Allocate a statement node of given kind and initialize all
 179  * fields with zero.
 180  */
 181 static statement_t *allocate_statement_zero(statement_kind_t kind)
 182 {
 183         size_t       size = get_statement_struct_size(kind);
 184         statement_t *res  = allocate_ast_zero(size);
 185
 186         res->base.kind = kind;
 187         return res;
 188 }
 189
 190 /**
 191  * Returns the size of an expression node.
 192  *
 193  * @param kind  the expression kind
 194  */
 195 static size_t get_expression_struct_size(expression_kind_t kind)
 196 {
 197         static const size_t sizes[] = {
 198                 [EXPR_INVALID]             = sizeof(expression_base_t),
 199                 [EXPR_REFERENCE]           = sizeof(reference_expression_t),
 200                 [EXPR_CONST]               = sizeof(const_expression_t),
 201                 [EXPR_CHAR_CONST]          = sizeof(const_expression_t),
 202                 [EXPR_STRING_LITERAL]      = sizeof(string_literal_expression_t),
 203                 [EXPR_WIDE_STRING_LITERAL] = sizeof(wide_string_literal_expression_t),
 204                 [EXPR_COMPOUND_LITERAL]    = sizeof(compound_literal_expression_t),
 205                 [EXPR_CALL]                = sizeof(call_expression_t),
 206                 [EXPR_UNARY_FIRST]         = sizeof(unary_expression_t),
 207                 [EXPR_BINARY_FIRST]        = sizeof(binary_expression_t),
 208                 [EXPR_CONDITIONAL]         = sizeof(conditional_expression_t),
 209                 [EXPR_SELECT]              = sizeof(select_expression_t),
 210                 [EXPR_ARRAY_ACCESS]        = sizeof(array_access_expression_t),
 211                 [EXPR_SIZEOF]              = sizeof(typeprop_expression_t),
 212                 [EXPR_ALIGNOF]             = sizeof(typeprop_expression_t),
 213                 [EXPR_CLASSIFY_TYPE]       = sizeof(classify_type_expression_t),
 214                 [EXPR_FUNCTION]            = sizeof(string_literal_expression_t),
 215                 [EXPR_PRETTY_FUNCTION]     = sizeof(string_literal_expression_t),
 216                 [EXPR_BUILTIN_SYMBOL]      = sizeof(builtin_symbol_expression_t),
 217                 [EXPR_BUILTIN_CONSTANT_P]  = sizeof(builtin_constant_expression_t),
 218                 [EXPR_BUILTIN_PREFETCH]    = sizeof(builtin_prefetch_expression_t),
 219                 [EXPR_OFFSETOF]            = sizeof(offsetof_expression_t),
 220                 [EXPR_VA_START]            = sizeof(va_start_expression_t),
 221                 [EXPR_VA_ARG]              = sizeof(va_arg_expression_t),
 222                 [EXPR_STATEMENT]           = sizeof(statement_expression_t),
 223         };
 224         if(kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
 225                 return sizes[EXPR_UNARY_FIRST];
 226         }
 227         if(kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
 228                 return sizes[EXPR_BINARY_FIRST];
 229         }
 230         assert(kind <= sizeof(sizes) / sizeof(sizes[0]));
 231         assert(sizes[kind] != 0);
 232         return sizes[kind];
 233 }
 234
 235 /**
 236  * Allocate an expression node of given kind and initialize all
 237  * fields with zero.
 238  */
 239 static expression_t *allocate_expression_zero(expression_kind_t kind)
 240 {
 241         size_t        size = get_expression_struct_size(kind);
 242         expression_t *res  = allocate_ast_zero(size);
 243
 244         res->base.kind = kind;
 245         res->base.type = type_error_type;
 246         return res;
 247 }
 248
 249 /**
 250  * Returns the size of a type node.
 251  *
 252  * @param kind  the type kind
 253  */
 254 static size_t get_type_struct_size(type_kind_t kind)
 255 {
 256         static const size_t sizes[] = {
 257                 [TYPE_ATOMIC]          = sizeof(atomic_type_t),
 258                 [TYPE_BITFIELD]        = sizeof(bitfield_type_t),
 259                 [TYPE_COMPOUND_STRUCT] = sizeof(compound_type_t),
 260                 [TYPE_COMPOUND_UNION]  = sizeof(compound_type_t),
 261                 [TYPE_ENUM]            = sizeof(enum_type_t),
 262                 [TYPE_FUNCTION]        = sizeof(function_type_t),
 263                 [TYPE_POINTER]         = sizeof(pointer_type_t),
 264                 [TYPE_ARRAY]           = sizeof(array_type_t),
 265                 [TYPE_BUILTIN]         = sizeof(builtin_type_t),
 266                 [TYPE_TYPEDEF]         = sizeof(typedef_type_t),
 267                 [TYPE_TYPEOF]          = sizeof(typeof_type_t),
 268         };
 269         assert(sizeof(sizes) / sizeof(sizes[0]) == (int) TYPE_TYPEOF + 1);
 270         assert(kind <= TYPE_TYPEOF);
 271         assert(sizes[kind] != 0);
 272         return sizes[kind];
 273 }
 274
 275 /**
 276  * Allocate a type node of given kind and initialize all
 277  * fields with zero.
 278  */
 279 static type_t *allocate_type_zero(type_kind_t kind, source_position_t source_position)
 280 {
 281         size_t  size = get_type_struct_size(kind);
 282         type_t *res  = obstack_alloc(type_obst, size);
 283         memset(res, 0, size);
 284
 285         res->base.kind            = kind;
 286         res->base.source_position = source_position;
 287         return res;
 288 }
 289
 290 /**
 291  * Returns the size of an initializer node.
 292  *
 293  * @param kind  the initializer kind
 294  */
 295 static size_t get_initializer_size(initializer_kind_t kind)
 296 {
 297         static const size_t sizes[] = {
 298                 [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
 299                 [INITIALIZER_STRING]      = sizeof(initializer_string_t),
 300                 [INITIALIZER_WIDE_STRING] = sizeof(initializer_wide_string_t),
 301                 [INITIALIZER_LIST]        = sizeof(initializer_list_t),
 302                 [INITIALIZER_DESIGNATOR]  = sizeof(initializer_designator_t)
 303         };
 304         assert(kind < sizeof(sizes) / sizeof(*sizes));
 305         assert(sizes[kind] != 0);
 306         return sizes[kind];
 307 }
 308
 309 /**
 310  * Allocate an initializer node of given kind and initialize all
 311  * fields with zero.
 312  */
 313 static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 314 {
 315         initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
 316         result->kind          = kind;
 317
 318         return result;
 319 }
 320
 321 /**
 322  * Free a type from the type obstack.
 323  */
 324 static void free_type(void *type)
 325 {
 326         obstack_free(type_obst, type);
 327 }
 328
 329 /**
 330  * Returns the index of the top element of the environment stack.
 331  */
 332 static size_t environment_top(void)
 333 {
 334         return ARR_LEN(environment_stack);
 335 }
 336
 337 /**
 338  * Returns the index of the top element of the label stack.
 339  */
 340 static size_t label_top(void)
 341 {
 342         return ARR_LEN(label_stack);
 343 }
 344
 345
 346 /**
 347  * Return the next token.
 348  */
 349 static inline void next_token(void)
 350 {
 351         token                              = lookahead_buffer[lookahead_bufpos];
 352         lookahead_buffer[lookahead_bufpos] = lexer_token;
 353         lexer_next_token();
 354
 355         lookahead_bufpos = (lookahead_bufpos+1) % MAX_LOOKAHEAD;
 356
 357 #ifdef PRINT_TOKENS
 358         print_token(stderr, &token);
 359         fprintf(stderr, "\n");
 360 #endif
 361 }
 362
 363 /**
 364  * Return the next token with a given lookahead.
 365  */
 366 static inline const token_t *look_ahead(int num)
 367 {
 368         assert(num > 0 && num <= MAX_LOOKAHEAD);
 369         int pos = (lookahead_bufpos+num-1) % MAX_LOOKAHEAD;
 370         return &lookahead_buffer[pos];
 371 }
 372
 373 #define eat(token_type)  do { assert(token.type == token_type); next_token(); } while(0)
 374
 375 /**
 376  * Report a parse error because an expected token was not found.
 377  */
 378 static void parse_error_expected(const char *message, ...)
 379 {
 380         if(message != NULL) {
 381                 errorf(HERE, "%s", message);
 382         }
 383         va_list ap;
 384         va_start(ap, message);
 385         errorf(HERE, "got %K, expected %#k", &token, &ap, ", ");
 386         va_end(ap);
 387 }
 388
 389 /**
 390  * Report a type error.
 391  */
 392 static void type_error(const char *msg, const source_position_t source_position,
 393                        type_t *type)
 394 {
 395         errorf(source_position, "%s, but found type '%T'", msg, type);
 396 }
 397
 398 /**
 399  * Report an incompatible type.
 400  */
 401 static void type_error_incompatible(const char *msg,
 402                 const source_position_t source_position, type_t *type1, type_t *type2)
 403 {
 404         errorf(source_position, "%s, incompatible types: '%T' - '%T'", msg, type1, type2);
 405 }
 406
 407 /**
 408  * Eat an complete block, ie. '{ ... }'.
 409  */
 410 static void eat_block(void)
 411 {
 412         if(token.type == '{')
 413                 next_token();
 414
 415         while(token.type != '}') {
 416                 if(token.type == T_EOF)
 417                         return;
 418                 if(token.type == '{') {
 419                         eat_block();
 420                         continue;
 421                 }
 422                 next_token();
 423         }
 424         eat('}');
 425 }
 426
 427 /**
 428  * Eat a statement until an ';' token.
 429  */
 430 static void eat_statement(void)
 431 {
 432         while(token.type != ';') {
 433                 if(token.type == T_EOF)
 434                         return;
 435                 if(token.type == '}')
 436                         return;
 437                 if(token.type == '{') {
 438                         eat_block();
 439                         continue;
 440                 }
 441                 next_token();
 442         }
 443         eat(';');
 444 }
 445
 446 /**
 447  * Eat a parenthesed term, ie. '( ... )'.
 448  */
 449 static void eat_paren(void)
 450 {
 451         if(token.type == '(')
 452                 next_token();
 453
 454         while(token.type != ')') {
 455                 if(token.type == T_EOF)
 456                         return;
 457                 if(token.type == ')' || token.type == ';' || token.type == '}') {
 458                         return;
 459                 }
 460                 if(token.type == '(') {
 461                         eat_paren();
 462                         continue;
 463                 }
 464                 if(token.type == '{') {
 465                         eat_block();
 466                         continue;
 467                 }
 468                 next_token();
 469         }
 470         eat(')');
 471 }
 472
 473 #define expect(expected)                           \
 474         do {                                           \
 475     if(UNLIKELY(token.type != (expected))) {       \
 476         parse_error_expected(NULL, (expected), 0); \
 477         eat_statement();                           \
 478         return NULL;                               \
 479     }                                              \
 480     next_token();                                  \
 481         } while(0)
 482
 483 #define expect_block(expected)                     \
 484         do {                                           \
 485     if(UNLIKELY(token.type != (expected))) {       \
 486         parse_error_expected(NULL, (expected), 0); \
 487         eat_block();                               \
 488         return NULL;                               \
 489     }                                              \
 490     next_token();                                  \
 491         } while(0)
 492
 493 #define expect_void(expected)                      \
 494         do {                                           \
 495     if(UNLIKELY(token.type != (expected))) {       \
 496         parse_error_expected(NULL, (expected), 0); \
 497         eat_statement();                           \
 498         return;                                    \
 499     }                                              \
 500     next_token();                                  \
 501     } while(0)
 502
 503 static void set_scope(scope_t *new_scope)
 504 {
 505         if(scope != NULL) {
 506                 scope->last_declaration = last_declaration;
 507         }
 508         scope = new_scope;
 509
 510         last_declaration = new_scope->last_declaration;
 511 }
 512
 513 /**
 514  * Search a symbol in a given namespace and returns its declaration or
 515  * NULL if this symbol was not found.
 516  */
 517 static declaration_t *get_declaration(const symbol_t *const symbol, const namespace_t namespc)
 518 {
 519         declaration_t *declaration = symbol->declaration;
 520         for( ; declaration != NULL; declaration = declaration->symbol_next) {
 521                 if(declaration->namespc == namespc)
 522                         return declaration;
 523         }
 524
 525         return NULL;
 526 }
 527
 528 /**
 529  * pushs an environment_entry on the environment stack and links the
 530  * corresponding symbol to the new entry
 531  */
 532 static void stack_push(stack_entry_t **stack_ptr, declaration_t *declaration)
 533 {
 534         symbol_t    *symbol  = declaration->symbol;
 535         namespace_t  namespc = (namespace_t) declaration->namespc;
 536
 537         /* replace/add declaration into declaration list of the symbol */
 538         declaration_t *iter = symbol->declaration;
 539         if (iter == NULL) {
 540                 symbol->declaration = declaration;
 541         } else {
 542                 declaration_t *iter_last = NULL;
 543                 for( ; iter != NULL; iter_last = iter, iter = iter->symbol_next) {
 544                         /* replace an entry? */
 545                         if(iter->namespc == namespc) {
 546                                 if(iter_last == NULL) {
 547                                         symbol->declaration = declaration;
 548                                 } else {
 549                                         iter_last->symbol_next = declaration;
 550                                 }
 551                                 declaration->symbol_next = iter->symbol_next;
 552                                 break;
 553                         }
 554                 }
 555                 if(iter == NULL) {
 556                         assert(iter_last->symbol_next == NULL);
 557                         iter_last->symbol_next = declaration;
 558                 }
 559         }
 560
 561         /* remember old declaration */
 562         stack_entry_t entry;
 563         entry.symbol          = symbol;
 564         entry.old_declaration = iter;
 565         entry.namespc         = (unsigned short) namespc;
 566         ARR_APP1(stack_entry_t, *stack_ptr, entry);
 567 }
 568
 569 static void environment_push(declaration_t *declaration)
 570 {
 571         assert(declaration->source_position.input_name != NULL);
 572         assert(declaration->parent_scope != NULL);
 573         stack_push(&environment_stack, declaration);
 574 }
 575
 576 static void label_push(declaration_t *declaration)
 577 {
 578         declaration->parent_scope = &current_function->scope;
 579         stack_push(&label_stack, declaration);
 580 }
 581
 582 /**
 583  * pops symbols from the environment stack until @p new_top is the top element
 584  */
 585 static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 586 {
 587         stack_entry_t *stack = *stack_ptr;
 588         size_t         top   = ARR_LEN(stack);
 589         size_t         i;
 590
 591         assert(new_top <= top);
 592         if(new_top == top)
 593                 return;
 594
 595         for(i = top; i > new_top; --i) {
 596                 stack_entry_t *entry = &stack[i - 1];
 597
 598                 declaration_t *old_declaration = entry->old_declaration;
 599                 symbol_t      *symbol          = entry->symbol;
 600                 namespace_t    namespc         = (namespace_t)entry->namespc;
 601
 602                 /* replace/remove declaration */
 603                 declaration_t *declaration = symbol->declaration;
 604                 assert(declaration != NULL);
 605                 if(declaration->namespc == namespc) {
 606                         if(old_declaration == NULL) {
 607                                 symbol->declaration = declaration->symbol_next;
 608                         } else {
 609                                 symbol->declaration = old_declaration;
 610                         }
 611                 } else {
 612                         declaration_t *iter_last = declaration;
 613                         declaration_t *iter      = declaration->symbol_next;
 614                         for( ; iter != NULL; iter_last = iter, iter = iter->symbol_next) {
 615                                 /* replace an entry? */
 616                                 if(iter->namespc == namespc) {
 617                                         assert(iter_last != NULL);
 618                                         iter_last->symbol_next = old_declaration;
 619                                         if(old_declaration != NULL) {
 620                                                 old_declaration->symbol_next = iter->symbol_next;
 621                                         }
 622                                         break;
 623                                 }
 624                         }
 625                         assert(iter != NULL);
 626                 }
 627         }
 628
 629         ARR_SHRINKLEN(*stack_ptr, (int) new_top);
 630 }
 631
 632 static void environment_pop_to(size_t new_top)
 633 {
 634         stack_pop_to(&environment_stack, new_top);
 635 }
 636
 637 static void label_pop_to(size_t new_top)
 638 {
 639         stack_pop_to(&label_stack, new_top);
 640 }
 641
 642
 643 static int get_rank(const type_t *type)
 644 {
 645         assert(!is_typeref(type));
 646         /* The C-standard allows promoting to int or unsigned int (see § 7.2.2
 647          * and esp. footnote 108). However we can't fold constants (yet), so we
 648          * can't decide whether unsigned int is possible, while int always works.
 649          * (unsigned int would be preferable when possible... for stuff like
 650          *  struct { enum { ... } bla : 4; } ) */
 651         if(type->kind == TYPE_ENUM)
 652                 return ATOMIC_TYPE_INT;
 653
 654         assert(type->kind == TYPE_ATOMIC);
 655         return type->atomic.akind;
 656 }
 657
 658 static type_t *promote_integer(type_t *type)
 659 {
 660         if(type->kind == TYPE_BITFIELD)
 661                 type = type->bitfield.base;
 662
 663         if(get_rank(type) < ATOMIC_TYPE_INT)
 664                 type = type_int;
 665
 666         return type;
 667 }
 668
 669 /**
 670  * Create a cast expression.
 671  *
 672  * @param expression  the expression to cast
 673  * @param dest_type   the destination type
 674  */
 675 static expression_t *create_cast_expression(expression_t *expression,
 676                                             type_t *dest_type)
 677 {
 678         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST_IMPLICIT);
 679
 680         cast->unary.value = expression;
 681         cast->base.type   = dest_type;
 682
 683         return cast;
 684 }
 685
 686 /**
 687  * Check if a given expression represents the 0 pointer constant.
 688  */
 689 static bool is_null_pointer_constant(const expression_t *expression)
 690 {
 691         /* skip void* cast */
 692         if(expression->kind == EXPR_UNARY_CAST
 693                         || expression->kind == EXPR_UNARY_CAST_IMPLICIT) {
 694                 expression = expression->unary.value;
 695         }
 696
 697         /* TODO: not correct yet, should be any constant integer expression
 698          * which evaluates to 0 */
 699         if (expression->kind != EXPR_CONST)
 700                 return false;
 701
 702         type_t *const type = skip_typeref(expression->base.type);
 703         if (!is_type_integer(type))
 704                 return false;
 705
 706         return expression->conste.v.int_value == 0;
 707 }
 708
 709 /**
 710  * Create an implicit cast expression.
 711  *
 712  * @param expression  the expression to cast
 713  * @param dest_type   the destination type
 714  */
 715 static expression_t *create_implicit_cast(expression_t *expression,
 716                                           type_t *dest_type)
 717 {
 718         type_t *const source_type = expression->base.type;
 719
 720         if (source_type == dest_type)
 721                 return expression;
 722
 723         return create_cast_expression(expression, dest_type);
 724 }
 725
 726 /** Implements the rules from § 6.5.16.1 */
 727 static type_t *semantic_assign(type_t *orig_type_left,
 728                             const expression_t *const right,
 729                             const char *context)
 730 {
 731         type_t *const orig_type_right = right->base.type;
 732         type_t *const type_left       = skip_typeref(orig_type_left);
 733         type_t *const type_right      = skip_typeref(orig_type_right);
 734
 735         if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
 736             (is_type_pointer(type_left) && is_null_pointer_constant(right)) ||
 737             (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
 738                 && is_type_pointer(type_right))) {
 739                 return orig_type_left;
 740         }
 741
 742         if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
 743                 type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
 744                 type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 745
 746                 /* the left type has all qualifiers from the right type */
 747                 unsigned missing_qualifiers
 748                         = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 749                 if(missing_qualifiers != 0) {
 750                         errorf(HERE, "destination type '%T' in %s from type '%T' lacks qualifiers '%Q' in pointed-to type", type_left, context, type_right, missing_qualifiers);
 751                         return orig_type_left;
 752                 }
 753
 754                 points_to_left  = get_unqualified_type(points_to_left);
 755                 points_to_right = get_unqualified_type(points_to_right);
 756
 757                 if (is_type_atomic(points_to_left, ATOMIC_TYPE_VOID) ||
 758                                 is_type_atomic(points_to_right, ATOMIC_TYPE_VOID)) {
 759                         return orig_type_left;
 760                 }
 761
 762                 if (!types_compatible(points_to_left, points_to_right)) {
 763                         warningf(right->base.source_position,
 764                                 "destination type '%T' in %s is incompatible with '%E' of type '%T'",
 765                                 orig_type_left, context, right, orig_type_right);
 766                 }
 767
 768                 return orig_type_left;
 769         }
 770
 771         if ((is_type_compound(type_left)  && is_type_compound(type_right))
 772                         || (is_type_builtin(type_left) && is_type_builtin(type_right))) {
 773                 type_t *const unqual_type_left  = get_unqualified_type(type_left);
 774                 type_t *const unqual_type_right = get_unqualified_type(type_right);
 775                 if (types_compatible(unqual_type_left, unqual_type_right)) {
 776                         return orig_type_left;
 777                 }
 778         }
 779
 780         if (!is_type_valid(type_left))
 781                 return type_left;
 782
 783         if (!is_type_valid(type_right))
 784                 return orig_type_right;
 785
 786         return NULL;
 787 }
 788
 789 static expression_t *parse_constant_expression(void)
 790 {
 791         /* start parsing at precedence 7 (conditional expression) */
 792         expression_t *result = parse_sub_expression(7);
 793
 794         if(!is_constant_expression(result)) {
 795                 errorf(result->base.source_position, "expression '%E' is not constant\n", result);
 796         }
 797
 798         return result;
 799 }
 800
 801 static expression_t *parse_assignment_expression(void)
 802 {
 803         /* start parsing at precedence 2 (assignment expression) */
 804         return parse_sub_expression(2);
 805 }
 806
 807 static type_t *make_global_typedef(const char *name, type_t *type)
 808 {
 809         symbol_t *const symbol       = symbol_table_insert(name);
 810
 811         declaration_t *const declaration = allocate_declaration_zero();
 812         declaration->namespc                = NAMESPACE_NORMAL;
 813         declaration->storage_class          = STORAGE_CLASS_TYPEDEF;
 814         declaration->declared_storage_class = STORAGE_CLASS_TYPEDEF;
 815         declaration->type                   = type;
 816         declaration->symbol                 = symbol;
 817         declaration->source_position        = builtin_source_position;
 818
 819         record_declaration(declaration);
 820
 821         type_t *typedef_type               = allocate_type_zero(TYPE_TYPEDEF, builtin_source_position);
 822         typedef_type->typedeft.declaration = declaration;
 823
 824         return typedef_type;
 825 }
 826
 827 static string_t parse_string_literals(void)
 828 {
 829         assert(token.type == T_STRING_LITERAL);
 830         string_t result = token.v.string;
 831
 832         next_token();
 833
 834         while (token.type == T_STRING_LITERAL) {
 835                 result = concat_strings(&result, &token.v.string);
 836                 next_token();
 837         }
 838
 839         return result;
 840 }
 841
 842 static void parse_attributes(void)
 843 {
 844         while(true) {
 845                 switch(token.type) {
 846                 case T___attribute__: {
 847                         next_token();
 848
 849                         expect_void('(');
 850                         int depth = 1;
 851                         while(depth > 0) {
 852                                 switch(token.type) {
 853                                 case T_EOF:
 854                                         errorf(HERE, "EOF while parsing attribute");
 855                                         break;
 856                                 case '(':
 857                                         next_token();
 858                                         depth++;
 859                                         break;
 860                                 case ')':
 861                                         next_token();
 862                                         depth--;
 863                                         break;
 864                                 default:
 865                                         next_token();
 866                                 }
 867                         }
 868                         break;
 869                 }
 870                 case T_asm:
 871                         next_token();
 872                         expect_void('(');
 873                         if(token.type != T_STRING_LITERAL) {
 874                                 parse_error_expected("while parsing assembler attribute",
 875                                                      T_STRING_LITERAL);
 876                                 eat_paren();
 877                                 break;
 878                         } else {
 879                                 parse_string_literals();
 880                         }
 881                         expect_void(')');
 882                         break;
 883                 default:
 884                         goto attributes_finished;
 885                 }
 886         }
 887
 888 attributes_finished:
 889         ;
 890 }
 891
 892 static designator_t *parse_designation(void)
 893 {
 894         designator_t *result = NULL;
 895         designator_t *last   = NULL;
 896
 897         while(true) {
 898                 designator_t *designator;
 899                 switch(token.type) {
 900                 case '[':
 901                         designator = allocate_ast_zero(sizeof(designator[0]));
 902                         designator->source_position = token.source_position;
 903                         next_token();
 904                         designator->array_index = parse_constant_expression();
 905                         expect(']');
 906                         break;
 907                 case '.':
 908                         designator = allocate_ast_zero(sizeof(designator[0]));
 909                         designator->source_position = token.source_position;
 910                         next_token();
 911                         if(token.type != T_IDENTIFIER) {
 912                                 parse_error_expected("while parsing designator",
 913                                                      T_IDENTIFIER, 0);
 914                                 return NULL;
 915                         }
 916                         designator->symbol = token.v.symbol;
 917                         next_token();
 918                         break;
 919                 default:
 920                         expect('=');
 921                         return result;
 922                 }
 923
 924                 assert(designator != NULL);
 925                 if(last != NULL) {
 926                         last->next = designator;
 927                 } else {
 928                         result = designator;
 929                 }
 930                 last = designator;
 931         }
 932 }
 933
 934 static initializer_t *initializer_from_string(array_type_t *type,
 935                                               const string_t *const string)
 936 {
 937         /* TODO: check len vs. size of array type */
 938         (void) type;
 939
 940         initializer_t *initializer = allocate_initializer_zero(INITIALIZER_STRING);
 941         initializer->string.string = *string;
 942
 943         return initializer;
 944 }
 945
 946 static initializer_t *initializer_from_wide_string(array_type_t *const type,
 947                                                    wide_string_t *const string)
 948 {
 949         /* TODO: check len vs. size of array type */
 950         (void) type;
 951
 952         initializer_t *const initializer =
 953                 allocate_initializer_zero(INITIALIZER_WIDE_STRING);
 954         initializer->wide_string.string = *string;
 955
 956         return initializer;
 957 }
 958
 959 static initializer_t *initializer_from_expression(type_t *orig_type,
 960                                                   expression_t *expression)
 961 {
 962         /* TODO check that expression is a constant expression */
 963
 964         /* § 6.7.8.14/15 char array may be initialized by string literals */
 965         type_t *type           = skip_typeref(orig_type);
 966         type_t *expr_type_orig = expression->base.type;
 967         type_t *expr_type      = skip_typeref(expr_type_orig);
 968         if (is_type_array(type) && expr_type->kind == TYPE_POINTER) {
 969                 array_type_t *const array_type   = &type->array;
 970                 type_t       *const element_type = skip_typeref(array_type->element_type);
 971
 972                 if (element_type->kind == TYPE_ATOMIC) {
 973                         atomic_type_kind_t akind = element_type->atomic.akind;
 974                         switch (expression->kind) {
 975                                 case EXPR_STRING_LITERAL:
 976                                         if (akind == ATOMIC_TYPE_CHAR
 977                                                         || akind == ATOMIC_TYPE_SCHAR
 978                                                         || akind == ATOMIC_TYPE_UCHAR) {
 979                                                 return initializer_from_string(array_type,
 980                                                         &expression->string.value);
 981                                         }
 982
 983                                 case EXPR_WIDE_STRING_LITERAL: {
 984                                         type_t *bare_wchar_type = skip_typeref(type_wchar_t);
 985                                         if (get_unqualified_type(element_type) == bare_wchar_type) {
 986                                                 return initializer_from_wide_string(array_type,
 987                                                         &expression->wide_string.value);
 988                                         }
 989                                 }
 990
 991                                 default:
 992                                         break;
 993                         }
 994                 }
 995         }
 996
 997         type_t *const res_type = semantic_assign(type, expression, "initializer");
 998         if (res_type == NULL)
 999                 return NULL;
1000
1001         initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
1002         result->value.value = create_implicit_cast(expression, res_type);
1003
1004         return result;
1005 }
1006
1007 static bool is_initializer_constant(const expression_t *expression)
1008 {
1009         return is_constant_expression(expression)
1010                 || is_address_constant(expression);
1011 }
1012
1013 static initializer_t *parse_scalar_initializer(type_t *type,
1014                                                bool must_be_constant)
1015 {
1016         /* there might be extra {} hierarchies */
1017         int braces = 0;
1018         while(token.type == '{') {
1019                 next_token();
1020                 if(braces == 0) {
1021                         warningf(HERE, "extra curly braces around scalar initializer");
1022                 }
1023                 braces++;
1024         }
1025
1026         expression_t *expression = parse_assignment_expression();
1027         if(must_be_constant && !is_initializer_constant(expression)) {
1028                 errorf(expression->base.source_position,
1029                        "Initialisation expression '%E' is not constant\n",
1030                        expression);
1031         }
1032
1033         initializer_t *initializer = initializer_from_expression(type, expression);
1034
1035         if(initializer == NULL) {
1036                 errorf(expression->base.source_position,
1037                        "expression '%E' doesn't match expected type '%T'",
1038                        expression, type);
1039                 /* TODO */
1040                 return NULL;
1041         }
1042
1043         bool additional_warning_displayed = false;
1044         while(braces > 0) {
1045                 if(token.type == ',') {
1046                         next_token();
1047                 }
1048                 if(token.type != '}') {
1049                         if(!additional_warning_displayed) {
1050                                 warningf(HERE, "additional elements in scalar initializer");
1051                                 additional_warning_displayed = true;
1052                         }
1053                 }
1054                 eat_block();
1055                 braces--;
1056         }
1057
1058         return initializer;
1059 }
1060
1061 typedef struct type_path_entry_t type_path_entry_t;
1062 struct type_path_entry_t {
1063         type_t *type;
1064         union {
1065                 size_t         index;
1066                 declaration_t *compound_entry;
1067         } v;
1068 };
1069
1070 typedef struct type_path_t type_path_t;
1071 struct type_path_t {
1072         type_path_entry_t *path;
1073         type_t            *top_type;     /**< type of the element the path points */
1074         size_t             max_index;    /**< largest index in outermost array */
1075         bool               invalid;
1076 };
1077
1078 static __attribute__((unused)) void debug_print_type_path(
1079                 const type_path_t *path)
1080 {
1081         size_t len = ARR_LEN(path->path);
1082
1083         if(path->invalid) {
1084                 fprintf(stderr, "invalid path");
1085                 return;
1086         }
1087
1088         for(size_t i = 0; i < len; ++i) {
1089                 const type_path_entry_t *entry = & path->path[i];
1090
1091                 type_t *type = skip_typeref(entry->type);
1092                 if(is_type_compound(type)) {
1093                         fprintf(stderr, ".%s", entry->v.compound_entry->symbol->string);
1094                 } else if(is_type_array(type)) {
1095                         fprintf(stderr, "[%u]", entry->v.index);
1096                 } else {
1097                         fprintf(stderr, "-INVALID-");
1098                 }
1099         }
1100         fprintf(stderr, "  (");
1101         print_type(path->top_type);
1102         fprintf(stderr, ")");
1103 }
1104
1105 static type_path_entry_t *get_type_path_top(const type_path_t *path)
1106 {
1107         size_t len = ARR_LEN(path->path);
1108         assert(len > 0);
1109         return & path->path[len-1];
1110 }
1111
1112 static type_path_entry_t *append_to_type_path(type_path_t *path)
1113 {
1114         size_t len = ARR_LEN(path->path);
1115         ARR_RESIZE(type_path_entry_t, path->path, len+1);
1116
1117         type_path_entry_t *result = & path->path[len];
1118         memset(result, 0, sizeof(result[0]));
1119         return result;
1120 }
1121
1122 static void descend_into_subtype(type_path_t *path)
1123 {
1124         type_t *orig_top_type = path->top_type;
1125         type_t *top_type      = skip_typeref(orig_top_type);
1126
1127         assert(is_type_compound(top_type) || is_type_array(top_type));
1128
1129         type_path_entry_t *top = append_to_type_path(path);
1130         top->type              = top_type;
1131
1132         if(is_type_compound(top_type)) {
1133                 declaration_t *declaration = top_type->compound.declaration;
1134                 declaration_t *entry       = declaration->scope.declarations;
1135
1136                 top->v.compound_entry = entry;
1137                 path->top_type        = entry->type;
1138         } else {
1139                 assert(is_type_array(top_type));
1140
1141                 top->v.index   = 0;
1142                 path->top_type = top_type->array.element_type;
1143         }
1144 }
1145
1146 static void ascend_from_subtype(type_path_t *path)
1147 {
1148         type_path_entry_t *top = get_type_path_top(path);
1149
1150         path->top_type = top->type;
1151
1152         size_t len = ARR_LEN(path->path);
1153         ARR_RESIZE(type_path_entry_t, path->path, len-1);
1154 }
1155
1156 static void ascend_to(type_path_t *path, size_t top_path_level)
1157 {
1158         size_t len = ARR_LEN(path->path);
1159         assert(len >= top_path_level);
1160
1161         while(len > top_path_level) {
1162                 ascend_from_subtype(path);
1163                 len = ARR_LEN(path->path);
1164         }
1165 }
1166
1167 static bool walk_designator(type_path_t *path, const designator_t *designator,
1168                             bool used_in_offsetof)
1169 {
1170         for( ; designator != NULL; designator = designator->next) {
1171                 type_path_entry_t *top       = get_type_path_top(path);
1172                 type_t            *orig_type = top->type;
1173
1174                 type_t *type = skip_typeref(orig_type);
1175
1176                 if(designator->symbol != NULL) {
1177                         symbol_t *symbol = designator->symbol;
1178                         if(!is_type_compound(type)) {
1179                                 if(is_type_valid(type)) {
1180                                         errorf(designator->source_position,
1181                                                "'.%Y' designator used for non-compound type '%T'",
1182                                                symbol, orig_type);
1183                                 }
1184                                 goto failed;
1185                         }
1186
1187                         declaration_t *declaration = type->compound.declaration;
1188                         declaration_t *iter        = declaration->scope.declarations;
1189                         for( ; iter != NULL; iter = iter->next) {
1190                                 if(iter->symbol == symbol) {
1191                                         break;
1192                                 }
1193                         }
1194                         if(iter == NULL) {
1195                                 errorf(designator->source_position,
1196                                        "'%T' has no member named '%Y'", orig_type, symbol);
1197                                 goto failed;
1198                         }
1199                         if(used_in_offsetof) {
1200                                 type_t *real_type = skip_typeref(iter->type);
1201                                 if(real_type->kind == TYPE_BITFIELD) {
1202                                         errorf(designator->source_position,
1203                                                "offsetof designator '%Y' may not specify bitfield",
1204                                                symbol);
1205                                         goto failed;
1206                                 }
1207                         }
1208
1209                         top->type             = orig_type;
1210                         top->v.compound_entry = iter;
1211                         orig_type             = iter->type;
1212                 } else {
1213                         expression_t *array_index = designator->array_index;
1214                         assert(designator->array_index != NULL);
1215
1216                         if(!is_type_array(type)) {
1217                                 if(is_type_valid(type)) {
1218                                         errorf(designator->source_position,
1219                                                "[%E] designator used for non-array type '%T'",
1220                                                array_index, orig_type);
1221                                 }
1222                                 goto failed;
1223                         }
1224                         if(!is_type_valid(array_index->base.type)) {
1225                                 goto failed;
1226                         }
1227
1228                         long index = fold_constant(array_index);
1229                         if(!used_in_offsetof) {
1230                                 if(index < 0) {
1231                                         errorf(designator->source_position,
1232                                                "array index [%E] must be positive", array_index);
1233                                         goto failed;
1234                                 }
1235                                 if(type->array.size_constant == true) {
1236                                         long array_size = type->array.size;
1237                                         if(index >= array_size) {
1238                                                 errorf(designator->source_position,
1239                                                                 "designator [%E] (%d) exceeds array size %d",
1240                                                                 array_index, index, array_size);
1241                                                 goto failed;
1242                                         }
1243                                 }
1244                         }
1245
1246                         top->type    = orig_type;
1247                         top->v.index = (size_t) index;
1248                         orig_type    = type->array.element_type;
1249                 }
1250                 path->top_type = orig_type;
1251
1252                 if(designator->next != NULL) {
1253                         descend_into_subtype(path);
1254                 }
1255         }
1256
1257         path->invalid  = false;
1258         return true;
1259
1260 failed:
1261         return false;
1262 }
1263
1264 static void advance_current_object(type_path_t *path, size_t top_path_level)
1265 {
1266         if(path->invalid)
1267                 return;
1268
1269         type_path_entry_t *top = get_type_path_top(path);
1270
1271         type_t *type = skip_typeref(top->type);
1272         if(is_type_union(type)) {
1273                 /* in unions only the first element is initialized */
1274                 top->v.compound_entry = NULL;
1275         } else if(is_type_struct(type)) {
1276                 declaration_t *entry = top->v.compound_entry;
1277
1278                 entry                 = entry->next;
1279                 top->v.compound_entry = entry;
1280                 if(entry != NULL) {
1281                         path->top_type = entry->type;
1282                         return;
1283                 }
1284         } else {
1285                 assert(is_type_array(type));
1286
1287                 top->v.index++;
1288
1289                 if(!type->array.size_constant || top->v.index < type->array.size) {
1290                         return;
1291                 }
1292         }
1293
1294         /* we're past the last member of the current sub-aggregate, try if we
1295          * can ascend in the type hierarchy and continue with another subobject */
1296         size_t len = ARR_LEN(path->path);
1297
1298         if(len > top_path_level) {
1299                 ascend_from_subtype(path);
1300                 advance_current_object(path, top_path_level);
1301         } else {
1302                 path->invalid = true;
1303         }
1304 }
1305
1306 static void skip_initializers(void)
1307 {
1308         if(token.type == '{')
1309                 next_token();
1310
1311         while(token.type != '}') {
1312                 if(token.type == T_EOF)
1313                         return;
1314                 if(token.type == '{') {
1315                         eat_block();
1316                         continue;
1317                 }
1318                 next_token();
1319         }
1320 }
1321
1322 static initializer_t *parse_sub_initializer(type_path_t *path,
1323                 type_t *outer_type, size_t top_path_level, bool must_be_constant)
1324 {
1325         type_t *orig_type = path->top_type;
1326         type_t *type      = skip_typeref(orig_type);
1327
1328         /* we can't do usefull stuff if we didn't even parse the type. Skip the
1329          * initializers in this case. */
1330         if(!is_type_valid(type)) {
1331                 skip_initializers();
1332                 return NULL;
1333         }
1334
1335         initializer_t **initializers = NEW_ARR_F(initializer_t*, 0);
1336
1337         while(true) {
1338                 designator_t *designator = NULL;
1339                 if(token.type == '.' || token.type == '[') {
1340                         designator = parse_designation();
1341
1342                         /* reset path to toplevel, evaluate designator from there */
1343                         ascend_to(path, top_path_level);
1344                         if(!walk_designator(path, designator, false)) {
1345                                 /* can't continue after designation error */
1346                                 goto end_error;
1347                         }
1348
1349                         initializer_t *designator_initializer
1350                                 = allocate_initializer_zero(INITIALIZER_DESIGNATOR);
1351                         designator_initializer->designator.designator = designator;
1352                         ARR_APP1(initializer_t*, initializers, designator_initializer);
1353                 }
1354
1355                 initializer_t *sub;
1356
1357                 if(token.type == '{') {
1358                         if(is_type_scalar(type)) {
1359                                 sub = parse_scalar_initializer(type, must_be_constant);
1360                         } else {
1361                                 eat('{');
1362                                 descend_into_subtype(path);
1363
1364                                 sub = parse_sub_initializer(path, orig_type, top_path_level+1,
1365                                                             must_be_constant);
1366
1367                                 ascend_from_subtype(path);
1368
1369                                 expect_block('}');
1370                         }
1371                 } else {
1372                         /* must be an expression */
1373                         expression_t *expression = parse_assignment_expression();
1374
1375                         if(must_be_constant && !is_initializer_constant(expression)) {
1376                                 errorf(expression->base.source_position,
1377                                        "Initialisation expression '%E' is not constant\n",
1378                                        expression);
1379                         }
1380
1381                         /* handle { "string" } special case */
1382                         if((expression->kind == EXPR_STRING_LITERAL
1383                                         || expression->kind == EXPR_WIDE_STRING_LITERAL)
1384                                         && outer_type != NULL) {
1385                                 sub = initializer_from_expression(outer_type, expression);
1386                                 if(sub != NULL) {
1387                                         if(token.type == ',') {
1388                                                 next_token();
1389                                         }
1390                                         if(token.type != '}') {
1391                                                 warningf(HERE, "excessive elements in initializer for type '%T'",
1392                                                                  orig_type);
1393                                         }
1394                                         /* TODO: eat , ... */
1395                                         return sub;
1396                                 }
1397                         }
1398
1399                         /* descend into subtypes until expression matches type */
1400                         while(true) {
1401                                 orig_type = path->top_type;
1402                                 type      = skip_typeref(orig_type);
1403
1404                                 sub = initializer_from_expression(orig_type, expression);
1405                                 if(sub != NULL) {
1406                                         break;
1407                                 }
1408                                 if(!is_type_valid(type)) {
1409                                         goto end_error;
1410                                 }
1411                                 if(is_type_scalar(type)) {
1412                                         errorf(expression->base.source_position,
1413                                                         "expression '%E' doesn't match expected type '%T'",
1414                                                         expression, orig_type);
1415                                         goto end_error;
1416                                 }
1417
1418                                 descend_into_subtype(path);
1419                         }
1420                 }
1421
1422                 /* update largest index of top array */
1423                 const type_path_entry_t *first      = &path->path[0];
1424                 type_t                  *first_type = first->type;
1425                 first_type                          = skip_typeref(first_type);
1426                 if(is_type_array(first_type)) {
1427                         size_t index = first->v.index;
1428                         if(index > path->max_index)
1429                                 path->max_index = index;
1430                 }
1431
1432                 /* append to initializers list */
1433                 ARR_APP1(initializer_t*, initializers, sub);
1434
1435                 if(token.type == '}') {
1436                         break;
1437                 }
1438                 expect(',');
1439                 if(token.type == '}') {
1440                         break;
1441                 }
1442
1443                 advance_current_object(path, top_path_level);
1444                 orig_type = path->top_type;
1445                 type      = skip_typeref(orig_type);
1446         }
1447
1448         size_t len  = ARR_LEN(initializers);
1449         size_t size = sizeof(initializer_list_t) + len * sizeof(initializers[0]);
1450         initializer_t *result = allocate_ast_zero(size);
1451         result->kind          = INITIALIZER_LIST;
1452         result->list.len      = len;
1453         memcpy(&result->list.initializers, initializers,
1454                len * sizeof(initializers[0]));
1455
1456         ascend_to(path, top_path_level);
1457
1458         return result;
1459
1460 end_error:
1461         skip_initializers();
1462         DEL_ARR_F(initializers);
1463         ascend_to(path, top_path_level);
1464         return NULL;
1465 }
1466
1467 typedef struct parse_initializer_env_t {
1468         type_t        *type;        /* the type of the initializer. In case of an
1469                                        array type with unspecified size this gets
1470                                        adjusted to the actual size. */
1471         initializer_t *initializer; /* initializer will be filled in here */
1472         bool           must_be_constant;
1473 } parse_initializer_env_t;
1474
1475 static void parse_initializer(parse_initializer_env_t *env)
1476 {
1477         type_t        *type   = skip_typeref(env->type);
1478         initializer_t *result = NULL;
1479         size_t         max_index;
1480
1481         if(is_type_scalar(type)) {
1482                 /* TODO: § 6.7.8.11; eat {} without warning */
1483                 result = parse_scalar_initializer(type, env->must_be_constant);
1484         } else if(token.type == '{') {
1485                 eat('{');
1486
1487                 type_path_t path;
1488                 memset(&path, 0, sizeof(path));
1489                 path.top_type = env->type;
1490                 path.path     = NEW_ARR_F(type_path_entry_t, 0);
1491
1492                 descend_into_subtype(&path);
1493
1494                 result = parse_sub_initializer(&path, env->type, 1,
1495                                                env->must_be_constant);
1496
1497                 max_index = path.max_index;
1498                 DEL_ARR_F(path.path);
1499
1500                 expect_void('}');
1501         } else {
1502                 /* parse_scalar_initializer also works in this case: we simply
1503                  * have an expression without {} around it */
1504                 result = parse_scalar_initializer(type, env->must_be_constant);
1505         }
1506
1507         /* § 6.7.5 (22)  array initializers for arrays with unknown size determine
1508          * the array type size */
1509         if(is_type_array(type) && type->array.size_expression == NULL
1510                         && result != NULL) {
1511                 size_t size;
1512                 switch (result->kind) {
1513                 case INITIALIZER_LIST:
1514                         size = max_index + 1;
1515                         break;
1516
1517                 case INITIALIZER_STRING:
1518                         size = result->string.string.size;
1519                         break;
1520
1521                 case INITIALIZER_WIDE_STRING:
1522                         size = result->wide_string.string.size;
1523                         break;
1524
1525                 default:
1526                         panic("invalid initializer type");
1527                 }
1528
1529                 expression_t *cnst       = allocate_expression_zero(EXPR_CONST);
1530                 cnst->base.type          = type_size_t;
1531                 cnst->conste.v.int_value = size;
1532
1533                 type_t *new_type = duplicate_type(type);
1534
1535                 new_type->array.size_expression = cnst;
1536                 new_type->array.size_constant   = true;
1537                 new_type->array.size            = size;
1538                 env->type = new_type;
1539         }
1540
1541         env->initializer = result;
1542 }
1543
1544 static declaration_t *append_declaration(declaration_t *declaration);
1545
1546 static declaration_t *parse_compound_type_specifier(bool is_struct)
1547 {
1548         if(is_struct) {
1549                 eat(T_struct);
1550         } else {
1551                 eat(T_union);
1552         }
1553
1554         symbol_t      *symbol      = NULL;
1555         declaration_t *declaration = NULL;
1556
1557         if (token.type == T___attribute__) {
1558                 /* TODO */
1559                 parse_attributes();
1560         }
1561
1562         if(token.type == T_IDENTIFIER) {
1563                 symbol = token.v.symbol;
1564                 next_token();
1565
1566                 if(is_struct) {
1567                         declaration = get_declaration(symbol, NAMESPACE_STRUCT);
1568                 } else {
1569                         declaration = get_declaration(symbol, NAMESPACE_UNION);
1570                 }
1571         } else if(token.type != '{') {
1572                 if(is_struct) {
1573                         parse_error_expected("while parsing struct type specifier",
1574                                              T_IDENTIFIER, '{', 0);
1575                 } else {
1576                         parse_error_expected("while parsing union type specifier",
1577                                              T_IDENTIFIER, '{', 0);
1578                 }
1579
1580                 return NULL;
1581         }
1582
1583         if(declaration == NULL) {
1584                 declaration = allocate_declaration_zero();
1585                 declaration->namespc         =
1586                         (is_struct ? NAMESPACE_STRUCT : NAMESPACE_UNION);
1587                 declaration->source_position = token.source_position;
1588                 declaration->symbol          = symbol;
1589                 declaration->parent_scope  = scope;
1590                 if (symbol != NULL) {
1591                         environment_push(declaration);
1592                 }
1593                 append_declaration(declaration);
1594         }
1595
1596         if(token.type == '{') {
1597                 if(declaration->init.is_defined) {
1598                         assert(symbol != NULL);
1599                         errorf(HERE, "multiple definitions of '%s %Y'",
1600                                is_struct ? "struct" : "union", symbol);
1601                         declaration->scope.declarations = NULL;
1602                 }
1603                 declaration->init.is_defined = true;
1604
1605                 parse_compound_type_entries(declaration);
1606                 parse_attributes();
1607         }
1608
1609         return declaration;
1610 }
1611
1612 static void parse_enum_entries(type_t *const enum_type)
1613 {
1614         eat('{');
1615
1616         if(token.type == '}') {
1617                 next_token();
1618                 errorf(HERE, "empty enum not allowed");
1619                 return;
1620         }
1621
1622         do {
1623                 if(token.type != T_IDENTIFIER) {
1624                         parse_error_expected("while parsing enum entry", T_IDENTIFIER, 0);
1625                         eat_block();
1626                         return;
1627                 }
1628
1629                 declaration_t *const entry = allocate_declaration_zero();
1630                 entry->storage_class   = STORAGE_CLASS_ENUM_ENTRY;
1631                 entry->type            = enum_type;
1632                 entry->symbol          = token.v.symbol;
1633                 entry->source_position = token.source_position;
1634                 next_token();
1635
1636                 if(token.type == '=') {
1637                         next_token();
1638                         expression_t *value = parse_constant_expression();
1639
1640                         value = create_implicit_cast(value, enum_type);
1641                         entry->init.enum_value = value;
1642
1643                         /* TODO semantic */
1644                 }
1645
1646                 record_declaration(entry);
1647
1648                 if(token.type != ',')
1649                         break;
1650                 next_token();
1651         } while(token.type != '}');
1652
1653         expect_void('}');
1654 }
1655
1656 static type_t *parse_enum_specifier(void)
1657 {
1658         eat(T_enum);
1659
1660         declaration_t *declaration;
1661         symbol_t      *symbol;
1662
1663         if(token.type == T_IDENTIFIER) {
1664                 symbol = token.v.symbol;
1665                 next_token();
1666
1667                 declaration = get_declaration(symbol, NAMESPACE_ENUM);
1668         } else if(token.type != '{') {
1669                 parse_error_expected("while parsing enum type specifier",
1670                                      T_IDENTIFIER, '{', 0);
1671                 return NULL;
1672         } else {
1673                 declaration = NULL;
1674                 symbol      = NULL;
1675         }
1676
1677         if(declaration == NULL) {
1678                 declaration = allocate_declaration_zero();
1679                 declaration->namespc         = NAMESPACE_ENUM;
1680                 declaration->source_position = token.source_position;
1681                 declaration->symbol          = symbol;
1682                 declaration->parent_scope  = scope;
1683         }
1684
1685         type_t *const type      = allocate_type_zero(TYPE_ENUM, declaration->source_position);
1686         type->enumt.declaration = declaration;
1687
1688         if(token.type == '{') {
1689                 if(declaration->init.is_defined) {
1690                         errorf(HERE, "multiple definitions of enum %Y", symbol);
1691                 }
1692                 if (symbol != NULL) {
1693                         environment_push(declaration);
1694                 }
1695                 append_declaration(declaration);
1696                 declaration->init.is_defined = 1;
1697
1698                 parse_enum_entries(type);
1699                 parse_attributes();
1700         }
1701
1702         return type;
1703 }
1704
1705 /**
1706  * if a symbol is a typedef to another type, return true
1707  */
1708 static bool is_typedef_symbol(symbol_t *symbol)
1709 {
1710         const declaration_t *const declaration =
1711                 get_declaration(symbol, NAMESPACE_NORMAL);
1712         return
1713                 declaration != NULL &&
1714                 declaration->storage_class == STORAGE_CLASS_TYPEDEF;
1715 }
1716
1717 static type_t *parse_typeof(void)
1718 {
1719         eat(T___typeof__);
1720
1721         type_t *type;
1722
1723         expect('(');
1724
1725         expression_t *expression  = NULL;
1726
1727 restart:
1728         switch(token.type) {
1729         case T___extension__:
1730                 /* this can be a prefix to a typename or an expression */
1731                 /* we simply eat it now. */
1732                 do {
1733                         next_token();
1734                 } while(token.type == T___extension__);
1735                 goto restart;
1736
1737         case T_IDENTIFIER:
1738                 if(is_typedef_symbol(token.v.symbol)) {
1739                         type = parse_typename();
1740                 } else {
1741                         expression = parse_expression();
1742                         type       = expression->base.type;
1743                 }
1744                 break;
1745
1746         TYPENAME_START
1747                 type = parse_typename();
1748                 break;
1749
1750         default:
1751                 expression = parse_expression();
1752                 type       = expression->base.type;
1753                 break;
1754         }
1755
1756         expect(')');
1757
1758         type_t *typeof_type              = allocate_type_zero(TYPE_TYPEOF, expression->base.source_position);
1759         typeof_type->typeoft.expression  = expression;
1760         typeof_type->typeoft.typeof_type = type;
1761
1762         return typeof_type;
1763 }
1764
1765 typedef enum {
1766         SPECIFIER_SIGNED    = 1 << 0,
1767         SPECIFIER_UNSIGNED  = 1 << 1,
1768         SPECIFIER_LONG      = 1 << 2,
1769         SPECIFIER_INT       = 1 << 3,
1770         SPECIFIER_DOUBLE    = 1 << 4,
1771         SPECIFIER_CHAR      = 1 << 5,
1772         SPECIFIER_SHORT     = 1 << 6,
1773         SPECIFIER_LONG_LONG = 1 << 7,
1774         SPECIFIER_FLOAT     = 1 << 8,
1775         SPECIFIER_BOOL      = 1 << 9,
1776         SPECIFIER_VOID      = 1 << 10,
1777 #ifdef PROVIDE_COMPLEX
1778         SPECIFIER_COMPLEX   = 1 << 11,
1779         SPECIFIER_IMAGINARY = 1 << 12,
1780 #endif
1781 } specifiers_t;
1782
1783 static type_t *create_builtin_type(symbol_t *const symbol,
1784                                    type_t *const real_type)
1785 {
1786         type_t *type            = allocate_type_zero(TYPE_BUILTIN, builtin_source_position);
1787         type->builtin.symbol    = symbol;
1788         type->builtin.real_type = real_type;
1789
1790         type_t *result = typehash_insert(type);
1791         if (type != result) {
1792                 free_type(type);
1793         }
1794
1795         return result;
1796 }
1797
1798 static type_t *get_typedef_type(symbol_t *symbol)
1799 {
1800         declaration_t *declaration = get_declaration(symbol, NAMESPACE_NORMAL);
1801         if(declaration == NULL
1802                         || declaration->storage_class != STORAGE_CLASS_TYPEDEF)
1803                 return NULL;
1804
1805         type_t *type               = allocate_type_zero(TYPE_TYPEDEF, declaration->source_position);
1806         type->typedeft.declaration = declaration;
1807
1808         return type;
1809 }
1810
1811 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
1812 {
1813         type_t   *type            = NULL;
1814         unsigned  type_qualifiers = 0;
1815         unsigned  type_specifiers = 0;
1816         int       newtype         = 0;
1817
1818         specifiers->source_position = token.source_position;
1819
1820         while(true) {
1821                 switch(token.type) {
1822
1823                 /* storage class */
1824 #define MATCH_STORAGE_CLASS(token, class)                                  \
1825                 case token:                                                        \
1826                         if(specifiers->declared_storage_class != STORAGE_CLASS_NONE) { \
1827                                 errorf(HERE, "multiple storage classes in declaration specifiers"); \
1828                         }                                                              \
1829                         specifiers->declared_storage_class = class;                    \
1830                         next_token();                                                  \
1831                         break;
1832
1833                 MATCH_STORAGE_CLASS(T_typedef,  STORAGE_CLASS_TYPEDEF)
1834                 MATCH_STORAGE_CLASS(T_extern,   STORAGE_CLASS_EXTERN)
1835                 MATCH_STORAGE_CLASS(T_static,   STORAGE_CLASS_STATIC)
1836                 MATCH_STORAGE_CLASS(T_auto,     STORAGE_CLASS_AUTO)
1837                 MATCH_STORAGE_CLASS(T_register, STORAGE_CLASS_REGISTER)
1838
1839                 case T___thread:
1840                         switch (specifiers->declared_storage_class) {
1841                         case STORAGE_CLASS_NONE:
1842                                 specifiers->declared_storage_class = STORAGE_CLASS_THREAD;
1843                                 break;
1844
1845                         case STORAGE_CLASS_EXTERN:
1846                                 specifiers->declared_storage_class = STORAGE_CLASS_THREAD_EXTERN;
1847                                 break;
1848
1849                         case STORAGE_CLASS_STATIC:
1850                                 specifiers->declared_storage_class = STORAGE_CLASS_THREAD_STATIC;
1851                                 break;
1852
1853                         default:
1854                                 errorf(HERE, "multiple storage classes in declaration specifiers");
1855                                 break;
1856                         }
1857                         next_token();
1858                         break;
1859
1860                 /* type qualifiers */
1861 #define MATCH_TYPE_QUALIFIER(token, qualifier)                          \
1862                 case token:                                                     \
1863                         type_qualifiers |= qualifier;                               \
1864                         next_token();                                               \
1865                         break;
1866
1867                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
1868                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
1869                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
1870
1871                 case T___extension__:
1872                         /* TODO */
1873                         next_token();
1874                         break;
1875
1876                 /* type specifiers */
1877 #define MATCH_SPECIFIER(token, specifier, name)                         \
1878                 case token:                                                     \
1879                         next_token();                                               \
1880                         if(type_specifiers & specifier) {                           \
1881                                 errorf(HERE, "multiple " name " type specifiers given"); \
1882                         } else {                                                    \
1883                                 type_specifiers |= specifier;                           \
1884                         }                                                           \
1885                         break;
1886
1887                 MATCH_SPECIFIER(T_void,       SPECIFIER_VOID,      "void")
1888                 MATCH_SPECIFIER(T_char,       SPECIFIER_CHAR,      "char")
1889                 MATCH_SPECIFIER(T_short,      SPECIFIER_SHORT,     "short")
1890                 MATCH_SPECIFIER(T_int,        SPECIFIER_INT,       "int")
1891                 MATCH_SPECIFIER(T_float,      SPECIFIER_FLOAT,     "float")
1892                 MATCH_SPECIFIER(T_double,     SPECIFIER_DOUBLE,    "double")
1893                 MATCH_SPECIFIER(T_signed,     SPECIFIER_SIGNED,    "signed")
1894                 MATCH_SPECIFIER(T_unsigned,   SPECIFIER_UNSIGNED,  "unsigned")
1895                 MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool")
1896 #ifdef PROVIDE_COMPLEX
1897                 MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex")
1898                 MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary")
1899 #endif
1900                 case T_forceinline:
1901                         /* only in microsoft mode */
1902                         specifiers->decl_modifiers |= DM_FORCEINLINE;
1903
1904                 case T_inline:
1905                         next_token();
1906                         specifiers->is_inline = true;
1907                         break;
1908
1909                 case T_long:
1910                         next_token();
1911                         if(type_specifiers & SPECIFIER_LONG_LONG) {
1912                                 errorf(HERE, "multiple type specifiers given");
1913                         } else if(type_specifiers & SPECIFIER_LONG) {
1914                                 type_specifiers |= SPECIFIER_LONG_LONG;
1915                         } else {
1916                                 type_specifiers |= SPECIFIER_LONG;
1917                         }
1918                         break;
1919
1920                 case T_struct: {
1921                         type = allocate_type_zero(TYPE_COMPOUND_STRUCT, HERE);
1922
1923                         type->compound.declaration = parse_compound_type_specifier(true);
1924                         break;
1925                 }
1926                 case T_union: {
1927                         type = allocate_type_zero(TYPE_COMPOUND_UNION, HERE);
1928
1929                         type->compound.declaration = parse_compound_type_specifier(false);
1930                         break;
1931                 }
1932                 case T_enum:
1933                         type = parse_enum_specifier();
1934                         break;
1935                 case T___typeof__:
1936                         type = parse_typeof();
1937                         break;
1938                 case T___builtin_va_list:
1939                         type = duplicate_type(type_valist);
1940                         next_token();
1941                         break;
1942
1943                 case T___attribute__:
1944                         parse_attributes();
1945                         break;
1946
1947                 case T_IDENTIFIER: {
1948                         /* only parse identifier if we haven't found a type yet */
1949                         if(type != NULL || type_specifiers != 0)
1950                                 goto finish_specifiers;
1951
1952                         type_t *typedef_type = get_typedef_type(token.v.symbol);
1953
1954                         if(typedef_type == NULL)
1955                                 goto finish_specifiers;
1956
1957                         next_token();
1958                         type = typedef_type;
1959                         break;
1960                 }
1961
1962                 /* function specifier */
1963                 default:
1964                         goto finish_specifiers;
1965                 }
1966         }
1967
1968 finish_specifiers:
1969
1970         if(type == NULL) {
1971                 atomic_type_kind_t atomic_type;
1972
1973                 /* match valid basic types */
1974                 switch(type_specifiers) {
1975                 case SPECIFIER_VOID:
1976                         atomic_type = ATOMIC_TYPE_VOID;
1977                         break;
1978                 case SPECIFIER_CHAR:
1979                         atomic_type = ATOMIC_TYPE_CHAR;
1980                         break;
1981                 case SPECIFIER_SIGNED | SPECIFIER_CHAR:
1982                         atomic_type = ATOMIC_TYPE_SCHAR;
1983                         break;
1984                 case SPECIFIER_UNSIGNED | SPECIFIER_CHAR:
1985                         atomic_type = ATOMIC_TYPE_UCHAR;
1986                         break;
1987                 case SPECIFIER_SHORT:
1988                 case SPECIFIER_SIGNED | SPECIFIER_SHORT:
1989                 case SPECIFIER_SHORT | SPECIFIER_INT:
1990                 case SPECIFIER_SIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
1991                         atomic_type = ATOMIC_TYPE_SHORT;
1992                         break;
1993                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT:
1994                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
1995                         atomic_type = ATOMIC_TYPE_USHORT;
1996                         break;
1997                 case SPECIFIER_INT:
1998                 case SPECIFIER_SIGNED:
1999                 case SPECIFIER_SIGNED | SPECIFIER_INT:
2000                         atomic_type = ATOMIC_TYPE_INT;
2001                         break;
2002                 case SPECIFIER_UNSIGNED:
2003                 case SPECIFIER_UNSIGNED | SPECIFIER_INT:
2004                         atomic_type = ATOMIC_TYPE_UINT;
2005                         break;
2006                 case SPECIFIER_LONG:
2007                 case SPECIFIER_SIGNED | SPECIFIER_LONG:
2008                 case SPECIFIER_LONG | SPECIFIER_INT:
2009                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2010                         atomic_type = ATOMIC_TYPE_LONG;
2011                         break;
2012                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:
2013                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2014                         atomic_type = ATOMIC_TYPE_ULONG;
2015                         break;
2016                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2017                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2018                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG | SPECIFIER_INT:
2019                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2020                         | SPECIFIER_INT:
2021                         atomic_type = ATOMIC_TYPE_LONGLONG;
2022                         break;
2023                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2024                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2025                         | SPECIFIER_INT:
2026                         atomic_type = ATOMIC_TYPE_ULONGLONG;
2027                         break;
2028                 case SPECIFIER_FLOAT:
2029                         atomic_type = ATOMIC_TYPE_FLOAT;
2030                         break;
2031                 case SPECIFIER_DOUBLE:
2032                         atomic_type = ATOMIC_TYPE_DOUBLE;
2033                         break;
2034                 case SPECIFIER_LONG | SPECIFIER_DOUBLE:
2035                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
2036                         break;
2037                 case SPECIFIER_BOOL:
2038                         atomic_type = ATOMIC_TYPE_BOOL;
2039                         break;
2040 #ifdef PROVIDE_COMPLEX
2041                 case SPECIFIER_FLOAT | SPECIFIER_COMPLEX:
2042                         atomic_type = ATOMIC_TYPE_FLOAT_COMPLEX;
2043                         break;
2044                 case SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
2045                         atomic_type = ATOMIC_TYPE_DOUBLE_COMPLEX;
2046                         break;
2047                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
2048                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE_COMPLEX;
2049                         break;
2050                 case SPECIFIER_FLOAT | SPECIFIER_IMAGINARY:
2051                         atomic_type = ATOMIC_TYPE_FLOAT_IMAGINARY;
2052                         break;
2053                 case SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
2054                         atomic_type = ATOMIC_TYPE_DOUBLE_IMAGINARY;
2055                         break;
2056                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
2057                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE_IMAGINARY;
2058                         break;
2059 #endif
2060                 default:
2061                         /* invalid specifier combination, give an error message */
2062                         if(type_specifiers == 0) {
2063                                 if (! strict_mode) {
2064                                         if (warning.implicit_int) {
2065                                                 warningf(HERE, "no type specifiers in declaration, using 'int'");
2066                                         }
2067                                         atomic_type = ATOMIC_TYPE_INT;
2068                                         break;
2069                                 } else {
2070                                         errorf(HERE, "no type specifiers given in declaration");
2071                                 }
2072                         } else if((type_specifiers & SPECIFIER_SIGNED) &&
2073                                   (type_specifiers & SPECIFIER_UNSIGNED)) {
2074                                 errorf(HERE, "signed and unsigned specifiers gives");
2075                         } else if(type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
2076                                 errorf(HERE, "only integer types can be signed or unsigned");
2077                         } else {
2078                                 errorf(HERE, "multiple datatypes in declaration");
2079                         }
2080                         atomic_type = ATOMIC_TYPE_INVALID;
2081                 }
2082
2083                 type               = allocate_type_zero(TYPE_ATOMIC, builtin_source_position);
2084                 type->atomic.akind = atomic_type;
2085                 newtype            = 1;
2086         } else {
2087                 if(type_specifiers != 0) {
2088                         errorf(HERE, "multiple datatypes in declaration");
2089                 }
2090         }
2091
2092         type->base.qualifiers = type_qualifiers;
2093
2094         type_t *result = typehash_insert(type);
2095         if(newtype && result != type) {
2096                 free_type(type);
2097         }
2098
2099         specifiers->type = result;
2100 }
2101
2102 static type_qualifiers_t parse_type_qualifiers(void)
2103 {
2104         type_qualifiers_t type_qualifiers = TYPE_QUALIFIER_NONE;
2105
2106         while(true) {
2107                 switch(token.type) {
2108                 /* type qualifiers */
2109                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
2110                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
2111                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
2112
2113                 default:
2114                         return type_qualifiers;
2115                 }
2116         }
2117 }
2118
2119 static declaration_t *parse_identifier_list(void)
2120 {
2121         declaration_t *declarations     = NULL;
2122         declaration_t *last_declaration = NULL;
2123         do {
2124                 declaration_t *const declaration = allocate_declaration_zero();
2125                 declaration->type            = NULL; /* a K&R parameter list has no types, yet */
2126                 declaration->source_position = token.source_position;
2127                 declaration->symbol          = token.v.symbol;
2128                 next_token();
2129
2130                 if(last_declaration != NULL) {
2131                         last_declaration->next = declaration;
2132                 } else {
2133                         declarations = declaration;
2134                 }
2135                 last_declaration = declaration;
2136
2137                 if(token.type != ',')
2138                         break;
2139                 next_token();
2140         } while(token.type == T_IDENTIFIER);
2141
2142         return declarations;
2143 }
2144
2145 static void semantic_parameter(declaration_t *declaration)
2146 {
2147         /* TODO: improve error messages */
2148
2149         if(declaration->declared_storage_class == STORAGE_CLASS_TYPEDEF) {
2150                 errorf(HERE, "typedef not allowed in parameter list");
2151         } else if(declaration->declared_storage_class != STORAGE_CLASS_NONE
2152                         && declaration->declared_storage_class != STORAGE_CLASS_REGISTER) {
2153                 errorf(HERE, "parameter may only have none or register storage class");
2154         }
2155
2156         type_t *const orig_type = declaration->type;
2157         type_t *      type      = skip_typeref(orig_type);
2158
2159         /* Array as last part of a parameter type is just syntactic sugar.  Turn it
2160          * into a pointer. § 6.7.5.3 (7) */
2161         if (is_type_array(type)) {
2162                 type_t *const element_type = type->array.element_type;
2163
2164                 type = make_pointer_type(element_type, type->base.qualifiers);
2165
2166                 declaration->type = type;
2167         }
2168
2169         if(is_type_incomplete(type)) {
2170                 errorf(HERE, "incomplete type '%T' not allowed for parameter '%Y'",
2171                        orig_type, declaration->symbol);
2172         }
2173 }
2174
2175 static declaration_t *parse_parameter(void)
2176 {
2177         declaration_specifiers_t specifiers;
2178         memset(&specifiers, 0, sizeof(specifiers));
2179
2180         parse_declaration_specifiers(&specifiers);
2181
2182         declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/true);
2183
2184         semantic_parameter(declaration);
2185
2186         return declaration;
2187 }
2188
2189 static declaration_t *parse_parameters(function_type_t *type)
2190 {
2191         if(token.type == T_IDENTIFIER) {
2192                 symbol_t *symbol = token.v.symbol;
2193                 if(!is_typedef_symbol(symbol)) {
2194                         type->kr_style_parameters = true;
2195                         return parse_identifier_list();
2196                 }
2197         }
2198
2199         if(token.type == ')') {
2200                 type->unspecified_parameters = 1;
2201                 return NULL;
2202         }
2203         if(token.type == T_void && look_ahead(1)->type == ')') {
2204                 next_token();
2205                 return NULL;
2206         }
2207
2208         declaration_t        *declarations = NULL;
2209         declaration_t        *declaration;
2210         declaration_t        *last_declaration = NULL;
2211         function_parameter_t *parameter;
2212         function_parameter_t *last_parameter = NULL;
2213
2214         while(true) {
2215                 switch(token.type) {
2216                 case T_DOTDOTDOT:
2217                         next_token();
2218                         type->variadic = 1;
2219                         return declarations;
2220
2221                 case T_IDENTIFIER:
2222                 case T___extension__:
2223                 DECLARATION_START
2224                         declaration = parse_parameter();
2225
2226                         parameter       = obstack_alloc(type_obst, sizeof(parameter[0]));
2227                         memset(parameter, 0, sizeof(parameter[0]));
2228                         parameter->type = declaration->type;
2229
2230                         if(last_parameter != NULL) {
2231                                 last_declaration->next = declaration;
2232                                 last_parameter->next   = parameter;
2233                         } else {
2234                                 type->parameters = parameter;
2235                                 declarations     = declaration;
2236                         }
2237                         last_parameter   = parameter;
2238                         last_declaration = declaration;
2239                         break;
2240
2241                 default:
2242                         return declarations;
2243                 }
2244                 if(token.type != ',')
2245                         return declarations;
2246                 next_token();
2247         }
2248 }
2249
2250 typedef enum {
2251         CONSTRUCT_INVALID,
2252         CONSTRUCT_POINTER,
2253         CONSTRUCT_FUNCTION,
2254         CONSTRUCT_ARRAY
2255 } construct_type_kind_t;
2256
2257 typedef struct construct_type_t construct_type_t;
2258 struct construct_type_t {
2259         construct_type_kind_t  kind;
2260         construct_type_t      *next;
2261 };
2262
2263 typedef struct parsed_pointer_t parsed_pointer_t;
2264 struct parsed_pointer_t {
2265         construct_type_t  construct_type;
2266         type_qualifiers_t type_qualifiers;
2267 };
2268
2269 typedef struct construct_function_type_t construct_function_type_t;
2270 struct construct_function_type_t {
2271         construct_type_t  construct_type;
2272         type_t           *function_type;
2273 };
2274
2275 typedef struct parsed_array_t parsed_array_t;
2276 struct parsed_array_t {
2277         construct_type_t  construct_type;
2278         type_qualifiers_t type_qualifiers;
2279         bool              is_static;
2280         bool              is_variable;
2281         expression_t     *size;
2282 };
2283
2284 typedef struct construct_base_type_t construct_base_type_t;
2285 struct construct_base_type_t {
2286         construct_type_t  construct_type;
2287         type_t           *type;
2288 };
2289
2290 static construct_type_t *parse_pointer_declarator(void)
2291 {
2292         eat('*');
2293
2294         parsed_pointer_t *pointer = obstack_alloc(&temp_obst, sizeof(pointer[0]));
2295         memset(pointer, 0, sizeof(pointer[0]));
2296         pointer->construct_type.kind = CONSTRUCT_POINTER;
2297         pointer->type_qualifiers     = parse_type_qualifiers();
2298
2299         return (construct_type_t*) pointer;
2300 }
2301
2302 static construct_type_t *parse_array_declarator(void)
2303 {
2304         eat('[');
2305
2306         parsed_array_t *array = obstack_alloc(&temp_obst, sizeof(array[0]));
2307         memset(array, 0, sizeof(array[0]));
2308         array->construct_type.kind = CONSTRUCT_ARRAY;
2309
2310         if(token.type == T_static) {
2311                 array->is_static = true;
2312                 next_token();
2313         }
2314
2315         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
2316         if(type_qualifiers != 0) {
2317                 if(token.type == T_static) {
2318                         array->is_static = true;
2319                         next_token();
2320                 }
2321         }
2322         array->type_qualifiers = type_qualifiers;
2323
2324         if(token.type == '*' && look_ahead(1)->type == ']') {
2325                 array->is_variable = true;
2326                 next_token();
2327         } else if(token.type != ']') {
2328                 array->size = parse_assignment_expression();
2329         }
2330
2331         expect(']');
2332
2333         return (construct_type_t*) array;
2334 }
2335
2336 static construct_type_t *parse_function_declarator(declaration_t *declaration)
2337 {
2338         eat('(');
2339
2340         type_t *type;
2341         if(declaration != NULL) {
2342                 type = allocate_type_zero(TYPE_FUNCTION, declaration->source_position);
2343         } else {
2344                 type = allocate_type_zero(TYPE_FUNCTION, token.source_position);
2345         }
2346
2347         declaration_t *parameters = parse_parameters(&type->function);
2348         if(declaration != NULL) {
2349                 declaration->scope.declarations = parameters;
2350         }
2351
2352         construct_function_type_t *construct_function_type =
2353                 obstack_alloc(&temp_obst, sizeof(construct_function_type[0]));
2354         memset(construct_function_type, 0, sizeof(construct_function_type[0]));
2355         construct_function_type->construct_type.kind = CONSTRUCT_FUNCTION;
2356         construct_function_type->function_type       = type;
2357
2358         expect(')');
2359
2360         return (construct_type_t*) construct_function_type;
2361 }
2362
2363 static construct_type_t *parse_inner_declarator(declaration_t *declaration,
2364                 bool may_be_abstract)
2365 {
2366         /* construct a single linked list of construct_type_t's which describe
2367          * how to construct the final declarator type */
2368         construct_type_t *first = NULL;
2369         construct_type_t *last  = NULL;
2370
2371         /* pointers */
2372         while(token.type == '*') {
2373                 construct_type_t *type = parse_pointer_declarator();
2374
2375                 if(last == NULL) {
2376                         first = type;
2377                         last  = type;
2378                 } else {
2379                         last->next = type;
2380                         last       = type;
2381                 }
2382         }
2383
2384         /* TODO: find out if this is correct */
2385         parse_attributes();
2386
2387         construct_type_t *inner_types = NULL;
2388
2389         switch(token.type) {
2390         case T_IDENTIFIER:
2391                 if(declaration == NULL) {
2392                         errorf(HERE, "no identifier expected in typename");
2393                 } else {
2394                         declaration->symbol          = token.v.symbol;
2395                         declaration->source_position = token.source_position;
2396                 }
2397                 next_token();
2398                 break;
2399         case '(':
2400                 next_token();
2401                 inner_types = parse_inner_declarator(declaration, may_be_abstract);
2402                 expect(')');
2403                 break;
2404         default:
2405                 if(may_be_abstract)
2406                         break;
2407                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', 0);
2408                 /* avoid a loop in the outermost scope, because eat_statement doesn't
2409                  * eat '}' */
2410                 if(token.type == '}' && current_function == NULL) {
2411                         next_token();
2412                 } else {
2413                         eat_statement();
2414                 }
2415                 return NULL;
2416         }
2417
2418         construct_type_t *p = last;
2419
2420         while(true) {
2421                 construct_type_t *type;
2422                 switch(token.type) {
2423                 case '(':
2424                         type = parse_function_declarator(declaration);
2425                         break;
2426                 case '[':
2427                         type = parse_array_declarator();
2428                         break;
2429                 default:
2430                         goto declarator_finished;
2431                 }
2432
2433                 /* insert in the middle of the list (behind p) */
2434                 if(p != NULL) {
2435                         type->next = p->next;
2436                         p->next    = type;
2437                 } else {
2438                         type->next = first;
2439                         first      = type;
2440                 }
2441                 if(last == p) {
2442                         last = type;
2443                 }
2444         }
2445
2446 declarator_finished:
2447         parse_attributes();
2448
2449         /* append inner_types at the end of the list, we don't to set last anymore
2450          * as it's not needed anymore */
2451         if(last == NULL) {
2452                 assert(first == NULL);
2453                 first = inner_types;
2454         } else {
2455                 last->next = inner_types;
2456         }
2457
2458         return first;
2459 }
2460
2461 static type_t *construct_declarator_type(construct_type_t *construct_list,
2462                                          type_t *type)
2463 {
2464         construct_type_t *iter = construct_list;
2465         for( ; iter != NULL; iter = iter->next) {
2466                 switch(iter->kind) {
2467                 case CONSTRUCT_INVALID:
2468                         panic("invalid type construction found");
2469                 case CONSTRUCT_FUNCTION: {
2470                         construct_function_type_t *construct_function_type
2471                                 = (construct_function_type_t*) iter;
2472
2473                         type_t *function_type = construct_function_type->function_type;
2474
2475                         function_type->function.return_type = type;
2476
2477                         type_t *skipped_return_type = skip_typeref(type);
2478                         if (is_type_function(skipped_return_type)) {
2479                                 errorf(HERE, "function returning function is not allowed");
2480                                 type = type_error_type;
2481                         } else if (is_type_array(skipped_return_type)) {
2482                                 errorf(HERE, "function returning array is not allowed");
2483                                 type = type_error_type;
2484                         } else {
2485                                 type = function_type;
2486                         }
2487                         break;
2488                 }
2489
2490                 case CONSTRUCT_POINTER: {
2491                         parsed_pointer_t *parsed_pointer = (parsed_pointer_t*) iter;
2492                         type_t           *pointer_type   = allocate_type_zero(TYPE_POINTER, (source_position_t){NULL, 0});
2493                         pointer_type->pointer.points_to  = type;
2494                         pointer_type->base.qualifiers    = parsed_pointer->type_qualifiers;
2495
2496                         type = pointer_type;
2497                         break;
2498                 }
2499
2500                 case CONSTRUCT_ARRAY: {
2501                         parsed_array_t *parsed_array  = (parsed_array_t*) iter;
2502                         type_t         *array_type    = allocate_type_zero(TYPE_ARRAY, (source_position_t){NULL, 0});
2503
2504                         expression_t *size_expression = parsed_array->size;
2505
2506                         array_type->base.qualifiers       = parsed_array->type_qualifiers;
2507                         array_type->array.element_type    = type;
2508                         array_type->array.is_static       = parsed_array->is_static;
2509                         array_type->array.is_variable     = parsed_array->is_variable;
2510                         array_type->array.size_expression = size_expression;
2511
2512                         if(size_expression != NULL &&
2513                                         is_constant_expression(size_expression)) {
2514                                 array_type->array.size_constant = true;
2515                                 array_type->array.size
2516                                         = fold_constant(size_expression);
2517                         }
2518
2519                         type_t *skipped_type = skip_typeref(type);
2520                         if (is_type_atomic(skipped_type, ATOMIC_TYPE_VOID)) {
2521                                 errorf(HERE, "array of void is not allowed");
2522                                 type = type_error_type;
2523                         } else {
2524                                 type = array_type;
2525                         }
2526                         break;
2527                 }
2528                 }
2529
2530                 type_t *hashed_type = typehash_insert(type);
2531                 if(hashed_type != type) {
2532                         /* the function type was constructed earlier freeing it here will
2533                          * destroy other types... */
2534                         if(iter->kind != CONSTRUCT_FUNCTION) {
2535                                 free_type(type);
2536                         }
2537                         type = hashed_type;
2538                 }
2539         }
2540
2541         return type;
2542 }
2543
2544 static declaration_t *parse_declarator(
2545                 const declaration_specifiers_t *specifiers, bool may_be_abstract)
2546 {
2547         declaration_t *const declaration    = allocate_declaration_zero();
2548         declaration->declared_storage_class = specifiers->declared_storage_class;
2549         declaration->modifiers              = specifiers->decl_modifiers;
2550         declaration->is_inline              = specifiers->is_inline;
2551
2552         declaration->storage_class          = specifiers->declared_storage_class;
2553         if(declaration->storage_class == STORAGE_CLASS_NONE
2554                         && scope != global_scope) {
2555                 declaration->storage_class = STORAGE_CLASS_AUTO;
2556         }
2557
2558         construct_type_t *construct_type
2559                 = parse_inner_declarator(declaration, may_be_abstract);
2560         type_t *const type = specifiers->type;
2561         declaration->type = construct_declarator_type(construct_type, type);
2562
2563         if(construct_type != NULL) {
2564                 obstack_free(&temp_obst, construct_type);
2565         }
2566
2567         return declaration;
2568 }
2569
2570 static type_t *parse_abstract_declarator(type_t *base_type)
2571 {
2572         construct_type_t *construct_type = parse_inner_declarator(NULL, 1);
2573
2574         type_t *result = construct_declarator_type(construct_type, base_type);
2575         if(construct_type != NULL) {
2576                 obstack_free(&temp_obst, construct_type);
2577         }
2578
2579         return result;
2580 }
2581
2582 static declaration_t *append_declaration(declaration_t* const declaration)
2583 {
2584         if (last_declaration != NULL) {
2585                 last_declaration->next = declaration;
2586         } else {
2587                 scope->declarations = declaration;
2588         }
2589         last_declaration = declaration;
2590         return declaration;
2591 }
2592
2593 /**
2594  * Check if the declaration of main is suspicious.  main should be a
2595  * function with external linkage, returning int, taking either zero
2596  * arguments, two, or three arguments of appropriate types, ie.
2597  *
2598  * int main([ int argc, char **argv [, char **env ] ]).
2599  *
2600  * @param decl    the declaration to check
2601  * @param type    the function type of the declaration
2602  */
2603 static void check_type_of_main(const declaration_t *const decl, const function_type_t *const func_type)
2604 {
2605         if (decl->storage_class == STORAGE_CLASS_STATIC) {
2606                 warningf(decl->source_position, "'main' is normally a non-static function");
2607         }
2608         if (skip_typeref(func_type->return_type) != type_int) {
2609                 warningf(decl->source_position, "return type of 'main' should be 'int', but is '%T'", func_type->return_type);
2610         }
2611         const function_parameter_t *parm = func_type->parameters;
2612         if (parm != NULL) {
2613                 type_t *const first_type = parm->type;
2614                 if (!types_compatible(skip_typeref(first_type), type_int)) {
2615                         warningf(decl->source_position, "first argument of 'main' should be 'int', but is '%T'", first_type);
2616                 }
2617                 parm = parm->next;
2618                 if (parm != NULL) {
2619                         type_t *const second_type = parm->type;
2620                         if (!types_compatible(skip_typeref(second_type), type_char_ptr_ptr)) {
2621                                 warningf(decl->source_position, "second argument of 'main' should be 'char**', but is '%T'", second_type);
2622                         }
2623                         parm = parm->next;
2624                         if (parm != NULL) {
2625                                 type_t *const third_type = parm->type;
2626                                 if (!types_compatible(skip_typeref(third_type), type_char_ptr_ptr)) {
2627                                         warningf(decl->source_position, "third argument of 'main' should be 'char**', but is '%T'", third_type);
2628                                 }
2629                                 parm = parm->next;
2630                                 if (parm != NULL) {
2631                                         warningf(decl->source_position, "'main' takes only zero, two or three arguments");
2632                                 }
2633                         }
2634                 } else {
2635                         warningf(decl->source_position, "'main' takes only zero, two or three arguments");
2636                 }
2637         }
2638 }
2639
2640 /**
2641  * Check if a symbol is the equal to "main".
2642  */
2643 static bool is_sym_main(const symbol_t *const sym)
2644 {
2645         return strcmp(sym->string, "main") == 0;
2646 }
2647
2648 static declaration_t *internal_record_declaration(
2649         declaration_t *const declaration,
2650         const bool is_function_definition)
2651 {
2652         const symbol_t *const symbol  = declaration->symbol;
2653         const namespace_t     namespc = (namespace_t)declaration->namespc;
2654
2655         type_t *const orig_type = declaration->type;
2656         type_t *const type      = skip_typeref(orig_type);
2657         if (is_type_function(type) &&
2658                         type->function.unspecified_parameters &&
2659                         warning.strict_prototypes) {
2660                 warningf(declaration->source_position,
2661                          "function declaration '%#T' is not a prototype",
2662                          orig_type, declaration->symbol);
2663         }
2664
2665         if (is_function_definition && warning.main && is_sym_main(symbol)) {
2666                 check_type_of_main(declaration, &type->function);
2667         }
2668
2669         assert(declaration->symbol != NULL);
2670         declaration_t *previous_declaration = get_declaration(symbol, namespc);
2671
2672         assert(declaration != previous_declaration);
2673         if (previous_declaration != NULL) {
2674                 if (previous_declaration->parent_scope == scope) {
2675                         /* can happen for K&R style declarations */
2676                         if(previous_declaration->type == NULL) {
2677                                 previous_declaration->type = declaration->type;
2678                         }
2679
2680                         const type_t *prev_type = skip_typeref(previous_declaration->type);
2681                         if (!types_compatible(type, prev_type)) {
2682                                 errorf(declaration->source_position,
2683                                        "declaration '%#T' is incompatible with "
2684                                        "previous declaration '%#T'",
2685                                        orig_type, symbol, previous_declaration->type, symbol);
2686                                 errorf(previous_declaration->source_position,
2687                                        "previous declaration of '%Y' was here", symbol);
2688                         } else {
2689                                 unsigned old_storage_class
2690                                         = previous_declaration->storage_class;
2691                                 unsigned new_storage_class = declaration->storage_class;
2692
2693                                 if(is_type_incomplete(prev_type)) {
2694                                         previous_declaration->type = type;
2695                                         prev_type                  = type;
2696                                 }
2697
2698                                 /* pretend no storage class means extern for function
2699                                  * declarations (except if the previous declaration is neither
2700                                  * none nor extern) */
2701                                 if (is_type_function(type)) {
2702                                         switch (old_storage_class) {
2703                                                 case STORAGE_CLASS_NONE:
2704                                                         old_storage_class = STORAGE_CLASS_EXTERN;
2705
2706                                                 case STORAGE_CLASS_EXTERN:
2707                                                         if (is_function_definition) {
2708                                                                 if (warning.missing_prototypes &&
2709                                                                     prev_type->function.unspecified_parameters &&
2710                                                                     !is_sym_main(symbol)) {
2711                                                                         warningf(declaration->source_position,
2712                                                                                  "no previous prototype for '%#T'",
2713                                                                                  orig_type, symbol);
2714                                                                 }
2715                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
2716                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
2717                                                         }
2718                                                         break;
2719
2720                                                 default: break;
2721                                         }
2722                                 }
2723
2724                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
2725                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
2726 warn_redundant_declaration:
2727                                         if (warning.redundant_decls) {
2728                                                 warningf(declaration->source_position,
2729                                                          "redundant declaration for '%Y'", symbol);
2730                                                 warningf(previous_declaration->source_position,
2731                                                          "previous declaration of '%Y' was here",
2732                                                          symbol);
2733                                         }
2734                                 } else if (current_function == NULL) {
2735                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
2736                                                         new_storage_class == STORAGE_CLASS_STATIC) {
2737                                                 errorf(declaration->source_position,
2738                                                        "static declaration of '%Y' follows non-static declaration",
2739                                                        symbol);
2740                                                 errorf(previous_declaration->source_position,
2741                                                        "previous declaration of '%Y' was here", symbol);
2742                                         } else {
2743                                                 if (old_storage_class != STORAGE_CLASS_EXTERN && !is_function_definition) {
2744                                                         goto warn_redundant_declaration;
2745                                                 }
2746                                                 if (new_storage_class == STORAGE_CLASS_NONE) {
2747                                                         previous_declaration->storage_class = STORAGE_CLASS_NONE;
2748                                                         previous_declaration->declared_storage_class = STORAGE_CLASS_NONE;
2749                                                 }
2750                                         }
2751                                 } else {
2752                                         if (old_storage_class == new_storage_class) {
2753                                                 errorf(declaration->source_position,
2754                                                        "redeclaration of '%Y'", symbol);
2755                                         } else {
2756                                                 errorf(declaration->source_position,
2757                                                        "redeclaration of '%Y' with different linkage",
2758                                                        symbol);
2759                                         }
2760                                         errorf(previous_declaration->source_position,
2761                                                "previous declaration of '%Y' was here", symbol);
2762                                 }
2763                         }
2764                         return previous_declaration;
2765                 }
2766         } else if (is_function_definition) {
2767                 if (declaration->storage_class != STORAGE_CLASS_STATIC) {
2768                         if (warning.missing_prototypes && !is_sym_main(symbol)) {
2769                                 warningf(declaration->source_position,
2770                                          "no previous prototype for '%#T'", orig_type, symbol);
2771                         } else if (warning.missing_declarations && !is_sym_main(symbol)) {
2772                                 warningf(declaration->source_position,
2773                                          "no previous declaration for '%#T'", orig_type,
2774                                          symbol);
2775                         }
2776                 }
2777         } else if (warning.missing_declarations &&
2778             scope == global_scope &&
2779             !is_type_function(type) && (
2780               declaration->storage_class == STORAGE_CLASS_NONE ||
2781               declaration->storage_class == STORAGE_CLASS_THREAD
2782             )) {
2783                 warningf(declaration->source_position,
2784                          "no previous declaration for '%#T'", orig_type, symbol);
2785         }
2786
2787         assert(declaration->parent_scope == NULL);
2788         assert(scope != NULL);
2789
2790         declaration->parent_scope = scope;
2791
2792         environment_push(declaration);
2793         return append_declaration(declaration);
2794 }
2795
2796 static declaration_t *record_declaration(declaration_t *declaration)
2797 {
2798         return internal_record_declaration(declaration, false);
2799 }
2800
2801 static declaration_t *record_function_definition(declaration_t *declaration)
2802 {
2803         return internal_record_declaration(declaration, true);
2804 }
2805
2806 static void parser_error_multiple_definition(declaration_t *declaration,
2807                 const source_position_t source_position)
2808 {
2809         errorf(source_position, "multiple definition of symbol '%Y'",
2810                declaration->symbol);
2811         errorf(declaration->source_position,
2812                "this is the location of the previous definition.");
2813 }
2814
2815 static bool is_declaration_specifier(const token_t *token,
2816                                      bool only_type_specifiers)
2817 {
2818         switch(token->type) {
2819                 TYPE_SPECIFIERS
2820                         return true;
2821                 case T_IDENTIFIER:
2822                         return is_typedef_symbol(token->v.symbol);
2823
2824                 case T___extension__:
2825                 STORAGE_CLASSES
2826                 TYPE_QUALIFIERS
2827                         return !only_type_specifiers;
2828
2829                 default:
2830                         return false;
2831         }
2832 }
2833
2834 static void parse_init_declarator_rest(declaration_t *declaration)
2835 {
2836         eat('=');
2837
2838         type_t *orig_type = declaration->type;
2839         type_t *type      = skip_typeref(orig_type);
2840
2841         if(declaration->init.initializer != NULL) {
2842                 parser_error_multiple_definition(declaration, token.source_position);
2843         }
2844
2845         bool must_be_constant = false;
2846         if(declaration->storage_class == STORAGE_CLASS_STATIC
2847                         || declaration->storage_class == STORAGE_CLASS_THREAD_STATIC
2848                         || declaration->parent_scope == global_scope) {
2849                 must_be_constant = true;
2850         }
2851
2852         parse_initializer_env_t env;
2853         env.type             = orig_type;
2854         env.must_be_constant = must_be_constant;
2855         parse_initializer(&env);
2856
2857         if(env.type != orig_type) {
2858                 orig_type         = env.type;
2859                 type              = skip_typeref(orig_type);
2860                 declaration->type = env.type;
2861         }
2862
2863         if(is_type_function(type)) {
2864                 errorf(declaration->source_position,
2865                        "initializers not allowed for function types at declator '%Y' (type '%T')",
2866                        declaration->symbol, orig_type);
2867         } else {
2868                 declaration->init.initializer = env.initializer;
2869         }
2870 }
2871
2872 /* parse rest of a declaration without any declarator */
2873 static void parse_anonymous_declaration_rest(
2874                 const declaration_specifiers_t *specifiers,
2875                 parsed_declaration_func finished_declaration)
2876 {
2877         eat(';');
2878
2879         declaration_t *const declaration    = allocate_declaration_zero();
2880         declaration->type                   = specifiers->type;
2881         declaration->declared_storage_class = specifiers->declared_storage_class;
2882         declaration->source_position        = specifiers->source_position;
2883
2884         if (declaration->declared_storage_class != STORAGE_CLASS_NONE) {
2885                 warningf(declaration->source_position, "useless storage class in empty declaration");
2886         }
2887         declaration->storage_class = STORAGE_CLASS_NONE;
2888
2889         type_t *type = declaration->type;
2890         switch (type->kind) {
2891                 case TYPE_COMPOUND_STRUCT:
2892                 case TYPE_COMPOUND_UNION: {
2893                         if (type->compound.declaration->symbol == NULL) {
2894                                 warningf(declaration->source_position, "unnamed struct/union that defines no instances");
2895                         }
2896                         break;
2897                 }
2898
2899                 case TYPE_ENUM:
2900                         break;
2901
2902                 default:
2903                         warningf(declaration->source_position, "empty declaration");
2904                         break;
2905         }
2906
2907         finished_declaration(declaration);
2908 }
2909
2910 static void parse_declaration_rest(declaration_t *ndeclaration,
2911                 const declaration_specifiers_t *specifiers,
2912                 parsed_declaration_func finished_declaration)
2913 {
2914         while(true) {
2915                 declaration_t *declaration = finished_declaration(ndeclaration);
2916
2917                 type_t *orig_type = declaration->type;
2918                 type_t *type      = skip_typeref(orig_type);
2919
2920                 if (type->kind != TYPE_FUNCTION &&
2921                     declaration->is_inline &&
2922                     is_type_valid(type)) {
2923                         warningf(declaration->source_position,
2924                                  "variable '%Y' declared 'inline'\n", declaration->symbol);
2925                 }
2926
2927                 if(token.type == '=') {
2928                         parse_init_declarator_rest(declaration);
2929                 }
2930
2931                 if(token.type != ',')
2932                         break;
2933                 eat(',');
2934
2935                 ndeclaration = parse_declarator(specifiers, /*may_be_abstract=*/false);
2936         }
2937         expect_void(';');
2938 }
2939
2940 static declaration_t *finished_kr_declaration(declaration_t *declaration)
2941 {
2942         symbol_t *symbol  = declaration->symbol;
2943         if(symbol == NULL) {
2944                 errorf(HERE, "anonymous declaration not valid as function parameter");
2945                 return declaration;
2946         }
2947         namespace_t namespc = (namespace_t) declaration->namespc;
2948         if(namespc != NAMESPACE_NORMAL) {
2949                 return record_declaration(declaration);
2950         }
2951
2952         declaration_t *previous_declaration = get_declaration(symbol, namespc);
2953         if(previous_declaration == NULL ||
2954                         previous_declaration->parent_scope != scope) {
2955                 errorf(HERE, "expected declaration of a function parameter, found '%Y'",
2956                        symbol);
2957                 return declaration;
2958         }
2959
2960         if(previous_declaration->type == NULL) {
2961                 previous_declaration->type          = declaration->type;
2962                 previous_declaration->declared_storage_class = declaration->declared_storage_class;
2963                 previous_declaration->storage_class = declaration->storage_class;
2964                 previous_declaration->parent_scope  = scope;
2965                 return previous_declaration;
2966         } else {
2967                 return record_declaration(declaration);
2968         }
2969 }
2970
2971 static void parse_declaration(parsed_declaration_func finished_declaration)
2972 {
2973         declaration_specifiers_t specifiers;
2974         memset(&specifiers, 0, sizeof(specifiers));
2975         parse_declaration_specifiers(&specifiers);
2976
2977         if(token.type == ';') {
2978                 parse_anonymous_declaration_rest(&specifiers, append_declaration);
2979         } else {
2980                 declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
2981                 parse_declaration_rest(declaration, &specifiers, finished_declaration);
2982         }
2983 }
2984
2985 static void parse_kr_declaration_list(declaration_t *declaration)
2986 {
2987         type_t *type = skip_typeref(declaration->type);
2988         if(!is_type_function(type))
2989                 return;
2990
2991         if(!type->function.kr_style_parameters)
2992                 return;
2993
2994         /* push function parameters */
2995         int       top        = environment_top();
2996         scope_t  *last_scope = scope;
2997         set_scope(&declaration->scope);
2998
2999         declaration_t *parameter = declaration->scope.declarations;
3000         for( ; parameter != NULL; parameter = parameter->next) {
3001                 assert(parameter->parent_scope == NULL);
3002                 parameter->parent_scope = scope;
3003                 environment_push(parameter);
3004         }
3005
3006         /* parse declaration list */
3007         while(is_declaration_specifier(&token, false)) {
3008                 parse_declaration(finished_kr_declaration);
3009         }
3010
3011         /* pop function parameters */
3012         assert(scope == &declaration->scope);
3013         set_scope(last_scope);
3014         environment_pop_to(top);
3015
3016         /* update function type */
3017         type_t *new_type = duplicate_type(type);
3018         new_type->function.kr_style_parameters = false;
3019
3020         function_parameter_t *parameters     = NULL;
3021         function_parameter_t *last_parameter = NULL;
3022
3023         declaration_t *parameter_declaration = declaration->scope.declarations;
3024         for( ; parameter_declaration != NULL;
3025                         parameter_declaration = parameter_declaration->next) {
3026                 type_t *parameter_type = parameter_declaration->type;
3027                 if(parameter_type == NULL) {
3028                         if (strict_mode) {
3029                                 errorf(HERE, "no type specified for function parameter '%Y'",
3030                                        parameter_declaration->symbol);
3031                         } else {
3032                                 if (warning.implicit_int) {
3033                                         warningf(HERE, "no type specified for function parameter '%Y', using 'int'",
3034                                                 parameter_declaration->symbol);
3035                                 }
3036                                 parameter_type              = type_int;
3037                                 parameter_declaration->type = parameter_type;
3038                         }
3039                 }
3040
3041                 semantic_parameter(parameter_declaration);
3042                 parameter_type = parameter_declaration->type;
3043
3044                 function_parameter_t *function_parameter
3045                         = obstack_alloc(type_obst, sizeof(function_parameter[0]));
3046                 memset(function_parameter, 0, sizeof(function_parameter[0]));
3047
3048                 function_parameter->type = parameter_type;
3049                 if(last_parameter != NULL) {
3050                         last_parameter->next = function_parameter;
3051                 } else {
3052                         parameters = function_parameter;
3053                 }
3054                 last_parameter = function_parameter;
3055         }
3056         new_type->function.parameters = parameters;
3057
3058         type = typehash_insert(new_type);
3059         if(type != new_type) {
3060                 obstack_free(type_obst, new_type);
3061         }
3062
3063         declaration->type = type;
3064 }
3065
3066 static bool first_err = true;
3067
3068 /**
3069  * When called with first_err set, prints the name of the current function,
3070  * else does noting.
3071  */
3072 static void print_in_function(void) {
3073         if (first_err) {
3074                 first_err = false;
3075                 diagnosticf("%s: In function '%Y':\n",
3076                         current_function->source_position.input_name,
3077                         current_function->symbol);
3078         }
3079 }
3080
3081 /**
3082  * Check if all labels are defined in the current function.
3083  * Check if all labels are used in the current function.
3084  */
3085 static void check_labels(void)
3086 {
3087         for (const goto_statement_t *goto_statement = goto_first;
3088             goto_statement != NULL;
3089             goto_statement = goto_statement->next) {
3090                 declaration_t *label = goto_statement->label;
3091
3092                 label->used = true;
3093                 if (label->source_position.input_name == NULL) {
3094                         print_in_function();
3095                         errorf(goto_statement->base.source_position,
3096                                "label '%Y' used but not defined", label->symbol);
3097                  }
3098         }
3099         goto_first = goto_last = NULL;
3100
3101         if (warning.unused_label) {
3102                 for (const label_statement_t *label_statement = label_first;
3103                          label_statement != NULL;
3104                          label_statement = label_statement->next) {
3105                         const declaration_t *label = label_statement->label;
3106
3107                         if (! label->used) {
3108                                 print_in_function();
3109                                 warningf(label_statement->base.source_position,
3110                                         "label '%Y' defined but not used", label->symbol);
3111                         }
3112                 }
3113         }
3114         label_first = label_last = NULL;
3115 }
3116
3117 /**
3118  * Check declarations of current_function for unused entities.
3119  */
3120 static void check_declarations(void)
3121 {
3122         if (warning.unused_parameter) {
3123                 const scope_t *scope = &current_function->scope;
3124
3125                 const declaration_t *parameter = scope->declarations;
3126                 for (; parameter != NULL; parameter = parameter->next) {
3127                         if (! parameter->used) {
3128                                 print_in_function();
3129                                 warningf(parameter->source_position,
3130                                         "unused parameter '%Y'", parameter->symbol);
3131                         }
3132                 }
3133         }
3134         if (warning.unused_variable) {
3135         }
3136 }
3137
3138 static void parse_external_declaration(void)
3139 {
3140         /* function-definitions and declarations both start with declaration
3141          * specifiers */
3142         declaration_specifiers_t specifiers;
3143         memset(&specifiers, 0, sizeof(specifiers));
3144         parse_declaration_specifiers(&specifiers);
3145
3146         /* must be a declaration */
3147         if(token.type == ';') {
3148                 parse_anonymous_declaration_rest(&specifiers, append_declaration);
3149                 return;
3150         }
3151
3152         /* declarator is common to both function-definitions and declarations */
3153         declaration_t *ndeclaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
3154
3155         /* must be a declaration */
3156         if(token.type == ',' || token.type == '=' || token.type == ';') {
3157                 parse_declaration_rest(ndeclaration, &specifiers, record_declaration);
3158                 return;
3159         }
3160
3161         /* must be a function definition */
3162         parse_kr_declaration_list(ndeclaration);
3163
3164         if(token.type != '{') {
3165                 parse_error_expected("while parsing function definition", '{', 0);
3166                 eat_statement();
3167                 return;
3168         }
3169
3170         type_t *type = ndeclaration->type;
3171
3172         /* note that we don't skip typerefs: the standard doesn't allow them here
3173          * (so we can't use is_type_function here) */
3174         if(type->kind != TYPE_FUNCTION) {
3175                 if (is_type_valid(type)) {
3176                         errorf(HERE, "declarator '%#T' has a body but is not a function type",
3177                                type, ndeclaration->symbol);
3178                 }
3179                 eat_block();
3180                 return;
3181         }
3182
3183         /* § 6.7.5.3 (14) a function definition with () means no
3184          * parameters (and not unspecified parameters) */
3185         if(type->function.unspecified_parameters) {
3186                 type_t *duplicate = duplicate_type(type);
3187                 duplicate->function.unspecified_parameters = false;
3188
3189                 type = typehash_insert(duplicate);
3190                 if(type != duplicate) {
3191                         obstack_free(type_obst, duplicate);
3192                 }
3193                 ndeclaration->type = type;
3194         }
3195
3196         declaration_t *const declaration = record_function_definition(ndeclaration);
3197         if(ndeclaration != declaration) {
3198                 declaration->scope = ndeclaration->scope;
3199         }
3200         type = skip_typeref(declaration->type);
3201
3202         /* push function parameters and switch scope */
3203         int       top        = environment_top();
3204         scope_t  *last_scope = scope;
3205         set_scope(&declaration->scope);
3206
3207         declaration_t *parameter = declaration->scope.declarations;
3208         for( ; parameter != NULL; parameter = parameter->next) {
3209                 if(parameter->parent_scope == &ndeclaration->scope) {
3210                         parameter->parent_scope = scope;
3211                 }
3212                 assert(parameter->parent_scope == NULL
3213                                 || parameter->parent_scope == scope);
3214                 parameter->parent_scope = scope;
3215                 environment_push(parameter);
3216         }
3217
3218         if(declaration->init.statement != NULL) {
3219                 parser_error_multiple_definition(declaration, token.source_position);
3220                 eat_block();
3221                 goto end_of_parse_external_declaration;
3222         } else {
3223                 /* parse function body */
3224                 int            label_stack_top      = label_top();
3225                 declaration_t *old_current_function = current_function;
3226                 current_function                    = declaration;
3227
3228                 declaration->init.statement = parse_compound_statement();
3229                 first_err = true;
3230                 check_labels();
3231                 check_declarations();
3232
3233                 assert(current_function == declaration);
3234                 current_function = old_current_function;
3235                 label_pop_to(label_stack_top);
3236         }
3237
3238 end_of_parse_external_declaration:
3239         assert(scope == &declaration->scope);
3240         set_scope(last_scope);
3241         environment_pop_to(top);
3242 }
3243
3244 static type_t *make_bitfield_type(type_t *base, expression_t *size,
3245                                   source_position_t source_position)
3246 {
3247         type_t *type        = allocate_type_zero(TYPE_BITFIELD, source_position);
3248         type->bitfield.base = base;
3249         type->bitfield.size = size;
3250
3251         return type;
3252 }
3253
3254 static declaration_t *find_compound_entry(declaration_t *compound_declaration,
3255                                           symbol_t *symbol)
3256 {
3257         declaration_t *iter = compound_declaration->scope.declarations;
3258         for( ; iter != NULL; iter = iter->next) {
3259                 if(iter->namespc != NAMESPACE_NORMAL)
3260                         continue;
3261
3262                 if(iter->symbol == NULL) {
3263                         type_t *type = skip_typeref(iter->type);
3264                         if(is_type_compound(type)) {
3265                                 declaration_t *result
3266                                         = find_compound_entry(type->compound.declaration, symbol);
3267                                 if(result != NULL)
3268                                         return result;
3269                         }
3270                         continue;
3271                 }
3272
3273                 if(iter->symbol == symbol) {
3274                         return iter;
3275                 }
3276         }
3277
3278         return NULL;
3279 }
3280
3281 static void parse_compound_declarators(declaration_t *struct_declaration,
3282                 const declaration_specifiers_t *specifiers)
3283 {
3284         declaration_t *last_declaration = struct_declaration->scope.declarations;
3285         if(last_declaration != NULL) {
3286                 while(last_declaration->next != NULL) {
3287                         last_declaration = last_declaration->next;
3288                 }
3289         }
3290
3291         while(1) {
3292                 declaration_t *declaration;
3293
3294                 if(token.type == ':') {
3295                         source_position_t source_position = HERE;
3296                         next_token();
3297
3298                         type_t *base_type = specifiers->type;
3299                         expression_t *size = parse_constant_expression();
3300
3301                         if(!is_type_integer(skip_typeref(base_type))) {
3302                                 errorf(HERE, "bitfield base type '%T' is not an integer type",
3303                                        base_type);
3304                         }
3305
3306                         type_t *type = make_bitfield_type(base_type, size, source_position);
3307
3308                         declaration                         = allocate_declaration_zero();
3309                         declaration->namespc                = NAMESPACE_NORMAL;
3310                         declaration->declared_storage_class = STORAGE_CLASS_NONE;
3311                         declaration->storage_class          = STORAGE_CLASS_NONE;
3312                         declaration->source_position        = source_position;
3313                         declaration->modifiers              = specifiers->decl_modifiers;
3314                         declaration->type                   = type;
3315                 } else {
3316                         declaration = parse_declarator(specifiers,/*may_be_abstract=*/true);
3317
3318                         type_t *orig_type = declaration->type;
3319                         type_t *type      = skip_typeref(orig_type);
3320
3321                         if(token.type == ':') {
3322                                 source_position_t source_position = HERE;
3323                                 next_token();
3324                                 expression_t *size = parse_constant_expression();
3325
3326                                 if(!is_type_integer(type)) {
3327                                         errorf(HERE, "bitfield base type '%T' is not an "
3328                                                "integer type", orig_type);
3329                                 }
3330
3331                                 type_t *bitfield_type = make_bitfield_type(orig_type, size, source_position);
3332                                 declaration->type = bitfield_type;
3333                         } else {
3334                                 /* TODO we ignore arrays for now... what is missing is a check
3335                                  * that they're at the end of the struct */
3336                                 if(is_type_incomplete(type) && !is_type_array(type)) {
3337                                         errorf(HERE,
3338                                                "compound member '%Y' has incomplete type '%T'",
3339                                                declaration->symbol, orig_type);
3340                                 } else if(is_type_function(type)) {
3341                                         errorf(HERE, "compound member '%Y' must not have function "
3342                                                "type '%T'", declaration->symbol, orig_type);
3343                                 }
3344                         }
3345                 }
3346
3347                 /* make sure we don't define a symbol multiple times */
3348                 symbol_t *symbol = declaration->symbol;
3349                 if(symbol != NULL) {
3350                         declaration_t *prev_decl
3351                                 = find_compound_entry(struct_declaration, symbol);
3352
3353                         if(prev_decl != NULL) {
3354                                 assert(prev_decl->symbol == symbol);
3355                                 errorf(declaration->source_position,
3356                                        "multiple declarations of symbol '%Y'", symbol);
3357                                 errorf(prev_decl->source_position,
3358                                        "previous declaration of '%Y' was here", symbol);
3359                         }
3360                 }
3361
3362                 /* append declaration */
3363                 if(last_declaration != NULL) {
3364                         last_declaration->next = declaration;
3365                 } else {
3366                         struct_declaration->scope.declarations = declaration;
3367                 }
3368                 last_declaration = declaration;
3369
3370                 if(token.type != ',')
3371                         break;
3372                 next_token();
3373         }
3374         expect_void(';');
3375 }
3376
3377 static void parse_compound_type_entries(declaration_t *compound_declaration)
3378 {
3379         eat('{');
3380
3381         while(token.type != '}' && token.type != T_EOF) {
3382                 declaration_specifiers_t specifiers;
3383                 memset(&specifiers, 0, sizeof(specifiers));
3384                 parse_declaration_specifiers(&specifiers);
3385
3386                 parse_compound_declarators(compound_declaration, &specifiers);
3387         }
3388         if(token.type == T_EOF) {
3389                 errorf(HERE, "EOF while parsing struct");
3390         }
3391         next_token();
3392 }
3393
3394 static type_t *parse_typename(void)
3395 {
3396         declaration_specifiers_t specifiers;
3397         memset(&specifiers, 0, sizeof(specifiers));
3398         parse_declaration_specifiers(&specifiers);
3399         if(specifiers.declared_storage_class != STORAGE_CLASS_NONE) {
3400                 /* TODO: improve error message, user does probably not know what a
3401                  * storage class is...
3402                  */
3403                 errorf(HERE, "typename may not have a storage class");
3404         }
3405
3406         type_t *result = parse_abstract_declarator(specifiers.type);
3407
3408         return result;
3409 }
3410
3411
3412
3413
3414 typedef expression_t* (*parse_expression_function) (unsigned precedence);
3415 typedef expression_t* (*parse_expression_infix_function) (unsigned precedence,
3416                                                           expression_t *left);
3417
3418 typedef struct expression_parser_function_t expression_parser_function_t;
3419 struct expression_parser_function_t {
3420         unsigned                         precedence;
3421         parse_expression_function        parser;
3422         unsigned                         infix_precedence;
3423         parse_expression_infix_function  infix_parser;
3424 };
3425
3426 expression_parser_function_t expression_parsers[T_LAST_TOKEN];
3427
3428 /**
3429  * Creates a new invalid expression.
3430  */
3431 static expression_t *create_invalid_expression(void)
3432 {
3433         expression_t *expression         = allocate_expression_zero(EXPR_INVALID);
3434         expression->base.source_position = token.source_position;
3435         return expression;
3436 }
3437
3438 /**
3439  * Prints an error message if an expression was expected but not read
3440  */
3441 static expression_t *expected_expression_error(void)
3442 {
3443         /* skip the error message if the error token was read */
3444         if (token.type != T_ERROR) {
3445                 errorf(HERE, "expected expression, got token '%K'", &token);
3446         }
3447         next_token();
3448
3449         return create_invalid_expression();
3450 }
3451
3452 /**
3453  * Parse a string constant.
3454  */
3455 static expression_t *parse_string_const(void)
3456 {
3457         wide_string_t wres;
3458         if (token.type == T_STRING_LITERAL) {
3459                 string_t res = token.v.string;
3460                 next_token();
3461                 while (token.type == T_STRING_LITERAL) {
3462                         res = concat_strings(&res, &token.v.string);
3463                         next_token();
3464                 }
3465                 if (token.type != T_WIDE_STRING_LITERAL) {
3466                         expression_t *const cnst = allocate_expression_zero(EXPR_STRING_LITERAL);
3467                         /* note: that we use type_char_ptr here, which is already the
3468                          * automatic converted type. revert_automatic_type_conversion
3469                          * will construct the array type */
3470                         cnst->base.type    = type_char_ptr;
3471                         cnst->string.value = res;
3472                         return cnst;
3473                 }
3474
3475                 wres = concat_string_wide_string(&res, &token.v.wide_string);
3476         } else {
3477                 wres = token.v.wide_string;
3478         }
3479         next_token();
3480
3481         for (;;) {
3482                 switch (token.type) {
3483                         case T_WIDE_STRING_LITERAL:
3484                                 wres = concat_wide_strings(&wres, &token.v.wide_string);
3485                                 break;
3486
3487                         case T_STRING_LITERAL:
3488                                 wres = concat_wide_string_string(&wres, &token.v.string);
3489                                 break;
3490
3491                         default: {
3492                                 expression_t *const cnst = allocate_expression_zero(EXPR_WIDE_STRING_LITERAL);
3493                                 cnst->base.type         = type_wchar_t_ptr;
3494                                 cnst->wide_string.value = wres;
3495                                 return cnst;
3496                         }
3497                 }
3498                 next_token();
3499         }
3500 }
3501
3502 /**
3503  * Parse an integer constant.
3504  */
3505 static expression_t *parse_int_const(void)
3506 {
3507         expression_t *cnst         = allocate_expression_zero(EXPR_CONST);
3508         cnst->base.source_position = HERE;
3509         cnst->base.type            = token.datatype;
3510         cnst->conste.v.int_value   = token.v.intvalue;
3511
3512         next_token();
3513
3514         return cnst;
3515 }
3516
3517 /**
3518  * Parse a character constant.
3519  */
3520 static expression_t *parse_char_const(void)
3521 {
3522         expression_t *cnst         = allocate_expression_zero(EXPR_CHAR_CONST);
3523         cnst->base.source_position = HERE;
3524         cnst->base.type            = token.datatype;
3525         cnst->conste.v.chars.begin = token.v.string.begin;
3526         cnst->conste.v.chars.size  = token.v.string.size;
3527
3528         if (cnst->conste.v.chars.size != 1) {
3529                 if (warning.multichar && (c_mode & _GNUC)) {
3530                         /* TODO */
3531                         warningf(HERE, "multi-character character constant");
3532                 } else {
3533                         errorf(HERE, "more than 1 characters in character constant");
3534                 }
3535         }
3536         next_token();
3537
3538         return cnst;
3539 }
3540
3541 /**
3542  * Parse a float constant.
3543  */
3544 static expression_t *parse_float_const(void)
3545 {
3546         expression_t *cnst         = allocate_expression_zero(EXPR_CONST);
3547         cnst->base.type            = token.datatype;
3548         cnst->conste.v.float_value = token.v.floatvalue;
3549
3550         next_token();
3551
3552         return cnst;
3553 }
3554
3555 static declaration_t *create_implicit_function(symbol_t *symbol,
3556                 const source_position_t source_position)
3557 {
3558         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION, source_position);
3559         ntype->function.return_type            = type_int;
3560         ntype->function.unspecified_parameters = true;
3561
3562         type_t *type = typehash_insert(ntype);
3563         if(type != ntype) {
3564                 free_type(ntype);
3565         }
3566
3567         declaration_t *const declaration    = allocate_declaration_zero();
3568         declaration->storage_class          = STORAGE_CLASS_EXTERN;
3569         declaration->declared_storage_class = STORAGE_CLASS_EXTERN;
3570         declaration->type                   = type;
3571         declaration->symbol                 = symbol;
3572         declaration->source_position        = source_position;
3573         declaration->parent_scope           = global_scope;
3574
3575         scope_t *old_scope = scope;
3576         set_scope(global_scope);
3577
3578         environment_push(declaration);
3579         /* prepends the declaration to the global declarations list */
3580         declaration->next   = scope->declarations;
3581         scope->declarations = declaration;
3582
3583         assert(scope == global_scope);
3584         set_scope(old_scope);
3585
3586         return declaration;
3587 }
3588
3589 /**
3590  * Creates a return_type (func)(argument_type) function type if not
3591  * already exists.
3592  *
3593  * @param return_type    the return type
3594  * @param argument_type  the argument type
3595  */
3596 static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
3597 {
3598         function_parameter_t *parameter
3599                 = obstack_alloc(type_obst, sizeof(parameter[0]));
3600         memset(parameter, 0, sizeof(parameter[0]));
3601         parameter->type = argument_type;
3602
3603         type_t *type               = allocate_type_zero(TYPE_FUNCTION, builtin_source_position);
3604         type->function.return_type = return_type;
3605         type->function.parameters  = parameter;
3606
3607         type_t *result = typehash_insert(type);
3608         if(result != type) {
3609                 free_type(type);
3610         }
3611
3612         return result;
3613 }
3614
3615 /**
3616  * Creates a function type for some function like builtins.
3617  *
3618  * @param symbol   the symbol describing the builtin
3619  */
3620 static type_t *get_builtin_symbol_type(symbol_t *symbol)
3621 {
3622         switch(symbol->ID) {
3623         case T___builtin_alloca:
3624                 return make_function_1_type(type_void_ptr, type_size_t);
3625         case T___builtin_nan:
3626                 return make_function_1_type(type_double, type_char_ptr);
3627         case T___builtin_nanf:
3628                 return make_function_1_type(type_float, type_char_ptr);
3629         case T___builtin_nand:
3630                 return make_function_1_type(type_long_double, type_char_ptr);
3631         case T___builtin_va_end:
3632                 return make_function_1_type(type_void, type_valist);
3633         default:
3634                 panic("not implemented builtin symbol found");
3635         }
3636 }
3637
3638 /**
3639  * Performs automatic type cast as described in § 6.3.2.1.
3640  *
3641  * @param orig_type  the original type
3642  */
3643 static type_t *automatic_type_conversion(type_t *orig_type)
3644 {
3645         type_t *type = skip_typeref(orig_type);
3646         if(is_type_array(type)) {
3647                 array_type_t *array_type   = &type->array;
3648                 type_t       *element_type = array_type->element_type;
3649                 unsigned      qualifiers   = array_type->type.qualifiers;
3650
3651                 return make_pointer_type(element_type, qualifiers);
3652         }
3653
3654         if(is_type_function(type)) {
3655                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
3656         }
3657
3658         return orig_type;
3659 }
3660
3661 /**
3662  * reverts the automatic casts of array to pointer types and function
3663  * to function-pointer types as defined § 6.3.2.1
3664  */
3665 type_t *revert_automatic_type_conversion(const expression_t *expression)
3666 {
3667         switch (expression->kind) {
3668                 case EXPR_REFERENCE: return expression->reference.declaration->type;
3669                 case EXPR_SELECT:    return expression->select.compound_entry->type;
3670
3671                 case EXPR_UNARY_DEREFERENCE: {
3672                         const expression_t *const value = expression->unary.value;
3673                         type_t             *const type  = skip_typeref(value->base.type);
3674                         assert(is_type_pointer(type));
3675                         return type->pointer.points_to;
3676                 }
3677
3678                 case EXPR_BUILTIN_SYMBOL:
3679                         return get_builtin_symbol_type(expression->builtin_symbol.symbol);
3680
3681                 case EXPR_ARRAY_ACCESS: {
3682                         const expression_t *array_ref = expression->array_access.array_ref;
3683                         type_t             *type_left = skip_typeref(array_ref->base.type);
3684                         if (!is_type_valid(type_left))
3685                                 return type_left;
3686                         assert(is_type_pointer(type_left));
3687                         return type_left->pointer.points_to;
3688                 }
3689
3690                 case EXPR_STRING_LITERAL: {
3691                         size_t size = expression->string.value.size;
3692                         return make_array_type(type_char, size, TYPE_QUALIFIER_NONE);
3693                 }
3694
3695                 case EXPR_WIDE_STRING_LITERAL: {
3696                         size_t size = expression->wide_string.value.size;
3697                         return make_array_type(type_wchar_t, size, TYPE_QUALIFIER_NONE);
3698                 }
3699
3700                 case EXPR_COMPOUND_LITERAL:
3701                         return expression->compound_literal.type;
3702
3703                 default: break;
3704         }
3705
3706         return expression->base.type;
3707 }
3708
3709 static expression_t *parse_reference(void)
3710 {
3711         expression_t *expression = allocate_expression_zero(EXPR_REFERENCE);
3712
3713         reference_expression_t *ref = &expression->reference;
3714         ref->symbol = token.v.symbol;
3715
3716         declaration_t *declaration = get_declaration(ref->symbol, NAMESPACE_NORMAL);
3717
3718         source_position_t source_position = token.source_position;
3719         next_token();
3720
3721         if(declaration == NULL) {
3722                 if (! strict_mode && token.type == '(') {
3723                         /* an implicitly defined function */
3724                         if (warning.implicit_function_declaration) {
3725                                 warningf(HERE, "implicit declaration of function '%Y'",
3726                                         ref->symbol);
3727                         }
3728
3729                         declaration = create_implicit_function(ref->symbol,
3730                                                                source_position);
3731                 } else {
3732                         errorf(HERE, "unknown symbol '%Y' found.", ref->symbol);
3733                         return create_invalid_expression();
3734                 }
3735         }
3736
3737         type_t *type         = declaration->type;
3738
3739         /* we always do the auto-type conversions; the & and sizeof parser contains
3740          * code to revert this! */
3741         type = automatic_type_conversion(type);
3742
3743         ref->declaration = declaration;
3744         ref->base.type   = type;
3745
3746         /* this declaration is used */
3747         declaration->used = true;
3748
3749         return expression;
3750 }
3751
3752 static void check_cast_allowed(expression_t *expression, type_t *dest_type)
3753 {
3754         (void) expression;
3755         (void) dest_type;
3756         /* TODO check if explicit cast is allowed and issue warnings/errors */
3757 }
3758
3759 static expression_t *parse_compound_literal(type_t *type)
3760 {
3761         expression_t *expression = allocate_expression_zero(EXPR_COMPOUND_LITERAL);
3762
3763         parse_initializer_env_t env;
3764         env.type             = type;
3765         env.must_be_constant = false;
3766         parse_initializer(&env);
3767         type = env.type;
3768
3769         expression->compound_literal.type        = type;
3770         expression->compound_literal.initializer = env.initializer;
3771         expression->base.type                    = automatic_type_conversion(type);
3772
3773         return expression;
3774 }
3775
3776 static expression_t *parse_cast(void)
3777 {
3778         source_position_t source_position = token.source_position;
3779
3780         type_t *type  = parse_typename();
3781
3782         expect(')');
3783
3784         if(token.type == '{') {
3785                 return parse_compound_literal(type);
3786         }
3787
3788         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
3789         cast->base.source_position = source_position;
3790
3791         expression_t *value = parse_sub_expression(20);
3792
3793         check_cast_allowed(value, type);
3794
3795         cast->base.type   = type;
3796         cast->unary.value = value;
3797
3798         return cast;
3799 }
3800
3801 static expression_t *parse_statement_expression(void)
3802 {
3803         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
3804
3805         statement_t *statement           = parse_compound_statement();
3806         expression->statement.statement  = statement;
3807         expression->base.source_position = statement->base.source_position;
3808
3809         /* find last statement and use its type */
3810         type_t *type = type_void;
3811         const statement_t *stmt = statement->compound.statements;
3812         if (stmt != NULL) {
3813                 while (stmt->base.next != NULL)
3814                         stmt = stmt->base.next;
3815
3816                 if (stmt->kind == STATEMENT_EXPRESSION) {
3817                         type = stmt->expression.expression->base.type;
3818                 }
3819         } else {
3820                 warningf(expression->base.source_position, "empty statement expression ({})");
3821         }
3822         expression->base.type = type;
3823
3824         expect(')');
3825
3826         return expression;
3827 }
3828
3829 static expression_t *parse_brace_expression(void)
3830 {
3831         eat('(');
3832
3833         switch(token.type) {
3834         case '{':
3835                 /* gcc extension: a statement expression */
3836                 return parse_statement_expression();
3837
3838         TYPE_QUALIFIERS
3839         TYPE_SPECIFIERS
3840                 return parse_cast();
3841         case T_IDENTIFIER:
3842                 if(is_typedef_symbol(token.v.symbol)) {
3843                         return parse_cast();
3844                 }
3845         }
3846
3847         expression_t *result = parse_expression();
3848         expect(')');
3849
3850         return result;
3851 }
3852
3853 static expression_t *parse_function_keyword(void)
3854 {
3855         next_token();
3856         /* TODO */
3857
3858         if (current_function == NULL) {
3859                 errorf(HERE, "'__func__' used outside of a function");
3860         }
3861
3862         expression_t *expression = allocate_expression_zero(EXPR_FUNCTION);
3863         expression->base.type    = type_char_ptr;
3864
3865         return expression;
3866 }
3867
3868 static expression_t *parse_pretty_function_keyword(void)
3869 {
3870         eat(T___PRETTY_FUNCTION__);
3871         /* TODO */
3872
3873         if (current_function == NULL) {
3874                 errorf(HERE, "'__PRETTY_FUNCTION__' used outside of a function");
3875         }
3876
3877         expression_t *expression = allocate_expression_zero(EXPR_PRETTY_FUNCTION);
3878         expression->base.type    = type_char_ptr;
3879
3880         return expression;
3881 }
3882
3883 static designator_t *parse_designator(void)
3884 {
3885         designator_t *result    = allocate_ast_zero(sizeof(result[0]));
3886         result->source_position = HERE;
3887
3888         if(token.type != T_IDENTIFIER) {
3889                 parse_error_expected("while parsing member designator",
3890                                      T_IDENTIFIER, 0);
3891                 eat_paren();
3892                 return NULL;
3893         }
3894         result->symbol = token.v.symbol;
3895         next_token();
3896
3897         designator_t *last_designator = result;
3898         while(true) {
3899                 if(token.type == '.') {
3900                         next_token();
3901                         if(token.type != T_IDENTIFIER) {
3902                                 parse_error_expected("while parsing member designator",
3903                                                      T_IDENTIFIER, 0);
3904                                 eat_paren();
3905                                 return NULL;
3906                         }
3907                         designator_t *designator    = allocate_ast_zero(sizeof(result[0]));
3908                         designator->source_position = HERE;
3909                         designator->symbol          = token.v.symbol;
3910                         next_token();
3911
3912                         last_designator->next = designator;
3913                         last_designator       = designator;
3914                         continue;
3915                 }
3916                 if(token.type == '[') {
3917                         next_token();
3918                         designator_t *designator    = allocate_ast_zero(sizeof(result[0]));
3919                         designator->source_position = HERE;
3920                         designator->array_index     = parse_expression();
3921                         if(designator->array_index == NULL) {
3922                                 eat_paren();
3923                                 return NULL;
3924                         }
3925                         expect(']');
3926
3927                         last_designator->next = designator;
3928                         last_designator       = designator;
3929                         continue;
3930                 }
3931                 break;
3932         }
3933
3934         return result;
3935 }
3936
3937 static expression_t *parse_offsetof(void)
3938 {
3939         eat(T___builtin_offsetof);
3940
3941         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
3942         expression->base.type    = type_size_t;
3943
3944         expect('(');
3945         type_t *type = parse_typename();
3946         expect(',');
3947         designator_t *designator = parse_designator();
3948         expect(')');
3949
3950         expression->offsetofe.type       = type;
3951         expression->offsetofe.designator = designator;
3952
3953         type_path_t path;
3954         memset(&path, 0, sizeof(path));
3955         path.top_type = type;
3956         path.path     = NEW_ARR_F(type_path_entry_t, 0);
3957
3958         descend_into_subtype(&path);
3959
3960         if(!walk_designator(&path, designator, true)) {
3961                 return create_invalid_expression();
3962         }
3963
3964         DEL_ARR_F(path.path);
3965
3966         return expression;
3967 }
3968
3969 static expression_t *parse_va_start(void)
3970 {
3971         eat(T___builtin_va_start);
3972
3973         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
3974
3975         expect('(');
3976         expression->va_starte.ap = parse_assignment_expression();
3977         expect(',');
3978         expression_t *const expr = parse_assignment_expression();
3979         if (expr->kind == EXPR_REFERENCE) {
3980                 declaration_t *const decl = expr->reference.declaration;
3981                 if (decl == NULL)
3982                         return create_invalid_expression();
3983                 if (decl->parent_scope == &current_function->scope &&
3984                     decl->next == NULL) {
3985                         expression->va_starte.parameter = decl;
3986                         expect(')');
3987                         return expression;
3988                 }
3989         }
3990         errorf(expr->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
3991
3992         return create_invalid_expression();
3993 }
3994
3995 static expression_t *parse_va_arg(void)
3996 {
3997         eat(T___builtin_va_arg);
3998
3999         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
4000
4001         expect('(');
4002         expression->va_arge.ap = parse_assignment_expression();
4003         expect(',');
4004         expression->base.type = parse_typename();
4005         expect(')');
4006
4007         return expression;
4008 }
4009
4010 static expression_t *parse_builtin_symbol(void)
4011 {
4012         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_SYMBOL);
4013
4014         symbol_t *symbol = token.v.symbol;
4015
4016         expression->builtin_symbol.symbol = symbol;
4017         next_token();
4018
4019         type_t *type = get_builtin_symbol_type(symbol);
4020         type = automatic_type_conversion(type);
4021
4022         expression->base.type = type;
4023         return expression;
4024 }
4025
4026 static expression_t *parse_builtin_constant(void)
4027 {
4028         eat(T___builtin_constant_p);
4029
4030         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
4031
4032         expect('(');
4033         expression->builtin_constant.value = parse_assignment_expression();
4034         expect(')');
4035         expression->base.type = type_int;
4036
4037         return expression;
4038 }
4039
4040 static expression_t *parse_builtin_prefetch(void)
4041 {
4042         eat(T___builtin_prefetch);
4043
4044         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_PREFETCH);
4045
4046         expect('(');
4047         expression->builtin_prefetch.adr = parse_assignment_expression();
4048         if (token.type == ',') {
4049                 next_token();
4050                 expression->builtin_prefetch.rw = parse_assignment_expression();
4051         }
4052         if (token.type == ',') {
4053                 next_token();
4054                 expression->builtin_prefetch.locality = parse_assignment_expression();
4055         }
4056         expect(')');
4057         expression->base.type = type_void;
4058
4059         return expression;
4060 }
4061
4062 static expression_t *parse_compare_builtin(void)
4063 {
4064         expression_t *expression;
4065
4066         switch(token.type) {
4067         case T___builtin_isgreater:
4068                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATER);
4069                 break;
4070         case T___builtin_isgreaterequal:
4071                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATEREQUAL);
4072                 break;
4073         case T___builtin_isless:
4074                 expression = allocate_expression_zero(EXPR_BINARY_ISLESS);
4075                 break;
4076         case T___builtin_islessequal:
4077                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSEQUAL);
4078                 break;
4079         case T___builtin_islessgreater:
4080                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSGREATER);
4081                 break;
4082         case T___builtin_isunordered:
4083                 expression = allocate_expression_zero(EXPR_BINARY_ISUNORDERED);
4084                 break;
4085         default:
4086                 panic("invalid compare builtin found");
4087                 break;
4088         }
4089         expression->base.source_position = HERE;
4090         next_token();
4091
4092         expect('(');
4093         expression->binary.left = parse_assignment_expression();
4094         expect(',');
4095         expression->binary.right = parse_assignment_expression();
4096         expect(')');
4097
4098         type_t *const orig_type_left  = expression->binary.left->base.type;
4099         type_t *const orig_type_right = expression->binary.right->base.type;
4100
4101         type_t *const type_left  = skip_typeref(orig_type_left);
4102         type_t *const type_right = skip_typeref(orig_type_right);
4103         if(!is_type_float(type_left) && !is_type_float(type_right)) {
4104                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4105                         type_error_incompatible("invalid operands in comparison",
4106                                 expression->base.source_position, orig_type_left, orig_type_right);
4107                 }
4108         } else {
4109                 semantic_comparison(&expression->binary);
4110         }
4111
4112         return expression;
4113 }
4114
4115 static expression_t *parse_builtin_expect(void)
4116 {
4117         eat(T___builtin_expect);
4118
4119         expression_t *expression
4120                 = allocate_expression_zero(EXPR_BINARY_BUILTIN_EXPECT);
4121
4122         expect('(');
4123         expression->binary.left = parse_assignment_expression();
4124         expect(',');
4125         expression->binary.right = parse_constant_expression();
4126         expect(')');
4127
4128         expression->base.type = expression->binary.left->base.type;
4129
4130         return expression;
4131 }
4132
4133 static expression_t *parse_assume(void) {
4134         eat(T_assume);
4135
4136         expression_t *expression
4137                 = allocate_expression_zero(EXPR_UNARY_ASSUME);
4138
4139         expect('(');
4140         expression->unary.value = parse_assignment_expression();
4141         expect(')');
4142
4143         expression->base.type = type_void;
4144         return expression;
4145 }
4146
4147 static expression_t *parse_primary_expression(void)
4148 {
4149         switch (token.type) {
4150                 case T_INTEGER:                  return parse_int_const();
4151                 case T_CHARS:                    return parse_char_const();
4152                 case T_FLOATINGPOINT:            return parse_float_const();
4153                 case T_STRING_LITERAL:
4154                 case T_WIDE_STRING_LITERAL:      return parse_string_const();
4155                 case T_IDENTIFIER:               return parse_reference();
4156                 case T___FUNCTION__:
4157                 case T___func__:                 return parse_function_keyword();
4158                 case T___PRETTY_FUNCTION__:      return parse_pretty_function_keyword();
4159                 case T___builtin_offsetof:       return parse_offsetof();
4160                 case T___builtin_va_start:       return parse_va_start();
4161                 case T___builtin_va_arg:         return parse_va_arg();
4162                 case T___builtin_expect:         return parse_builtin_expect();
4163                 case T___builtin_alloca:
4164                 case T___builtin_nan:
4165                 case T___builtin_nand:
4166                 case T___builtin_nanf:
4167                 case T___builtin_va_end:         return parse_builtin_symbol();
4168                 case T___builtin_isgreater:
4169                 case T___builtin_isgreaterequal:
4170                 case T___builtin_isless:
4171                 case T___builtin_islessequal:
4172                 case T___builtin_islessgreater:
4173                 case T___builtin_isunordered:    return parse_compare_builtin();
4174                 case T___builtin_constant_p:     return parse_builtin_constant();
4175                 case T___builtin_prefetch:       return parse_builtin_prefetch();
4176                 case T_assume:                   return parse_assume();
4177
4178                 case '(':                        return parse_brace_expression();
4179         }
4180
4181         errorf(HERE, "unexpected token %K, expected an expression", &token);
4182         eat_statement();
4183
4184         return create_invalid_expression();
4185 }
4186
4187 /**
4188  * Check if the expression has the character type and issue a warning then.
4189  */
4190 static void check_for_char_index_type(const expression_t *expression) {
4191         type_t       *const type      = expression->base.type;
4192         const type_t *const base_type = skip_typeref(type);
4193
4194         if (is_type_atomic(base_type, ATOMIC_TYPE_CHAR) &&
4195                         warning.char_subscripts) {
4196                 warningf(expression->base.source_position,
4197                         "array subscript has type '%T'", type);
4198         }
4199 }
4200
4201 static expression_t *parse_array_expression(unsigned precedence,
4202                                             expression_t *left)
4203 {
4204         (void) precedence;
4205
4206         eat('[');
4207
4208         expression_t *inside = parse_expression();
4209
4210         expression_t *expression = allocate_expression_zero(EXPR_ARRAY_ACCESS);
4211
4212         array_access_expression_t *array_access = &expression->array_access;
4213
4214         type_t *const orig_type_left   = left->base.type;
4215         type_t *const orig_type_inside = inside->base.type;
4216
4217         type_t *const type_left   = skip_typeref(orig_type_left);
4218         type_t *const type_inside = skip_typeref(orig_type_inside);
4219
4220         type_t *return_type;
4221         if (is_type_pointer(type_left)) {
4222                 return_type             = type_left->pointer.points_to;
4223                 array_access->array_ref = left;
4224                 array_access->index     = inside;
4225                 check_for_char_index_type(inside);
4226         } else if (is_type_pointer(type_inside)) {
4227                 return_type             = type_inside->pointer.points_to;
4228                 array_access->array_ref = inside;
4229                 array_access->index     = left;
4230                 array_access->flipped   = true;
4231                 check_for_char_index_type(left);
4232         } else {
4233                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
4234                         errorf(HERE,
4235                                 "array access on object with non-pointer types '%T', '%T'",
4236                                 orig_type_left, orig_type_inside);
4237                 }
4238                 return_type             = type_error_type;
4239                 array_access->array_ref = create_invalid_expression();
4240         }
4241
4242         if(token.type != ']') {
4243                 parse_error_expected("Problem while parsing array access", ']', 0);
4244                 return expression;
4245         }
4246         next_token();
4247
4248         return_type           = automatic_type_conversion(return_type);
4249         expression->base.type = return_type;
4250
4251         return expression;
4252 }
4253
4254 static expression_t *parse_typeprop(expression_kind_t kind, unsigned precedence)
4255 {
4256         expression_t *tp_expression = allocate_expression_zero(kind);
4257         tp_expression->base.type    = type_size_t;
4258
4259         if(token.type == '(' && is_declaration_specifier(look_ahead(1), true)) {
4260                 next_token();
4261                 tp_expression->typeprop.type = parse_typename();
4262                 expect(')');
4263         } else {
4264                 expression_t *expression = parse_sub_expression(precedence);
4265                 expression->base.type    = revert_automatic_type_conversion(expression);
4266
4267                 tp_expression->typeprop.type          = expression->base.type;
4268                 tp_expression->typeprop.tp_expression = expression;
4269         }
4270
4271         return tp_expression;
4272 }
4273
4274 static expression_t *parse_sizeof(unsigned precedence)
4275 {
4276         eat(T_sizeof);
4277         return parse_typeprop(EXPR_SIZEOF, precedence);
4278 }
4279
4280 static expression_t *parse_alignof(unsigned precedence)
4281 {
4282         eat(T___alignof__);
4283         return parse_typeprop(EXPR_SIZEOF, precedence);
4284 }
4285
4286 static expression_t *parse_select_expression(unsigned precedence,
4287                                              expression_t *compound)
4288 {
4289         (void) precedence;
4290         assert(token.type == '.' || token.type == T_MINUSGREATER);
4291
4292         bool is_pointer = (token.type == T_MINUSGREATER);
4293         next_token();
4294
4295         expression_t *select    = allocate_expression_zero(EXPR_SELECT);
4296         select->select.compound = compound;
4297
4298         if(token.type != T_IDENTIFIER) {
4299                 parse_error_expected("while parsing select", T_IDENTIFIER, 0);
4300                 return select;
4301         }
4302         symbol_t *symbol      = token.v.symbol;
4303         select->select.symbol = symbol;
4304         next_token();
4305
4306         type_t *const orig_type = compound->base.type;
4307         type_t *const type      = skip_typeref(orig_type);
4308
4309         type_t *type_left = type;
4310         if(is_pointer) {
4311                 if (!is_type_pointer(type)) {
4312                         if (is_type_valid(type)) {
4313                                 errorf(HERE, "left hand side of '->' is not a pointer, but '%T'", orig_type);
4314                         }
4315                         return create_invalid_expression();
4316                 }
4317                 type_left = type->pointer.points_to;
4318         }
4319         type_left = skip_typeref(type_left);
4320
4321         if (type_left->kind != TYPE_COMPOUND_STRUCT &&
4322             type_left->kind != TYPE_COMPOUND_UNION) {
4323                 if (is_type_valid(type_left)) {
4324                         errorf(HERE, "request for member '%Y' in something not a struct or "
4325                                "union, but '%T'", symbol, type_left);
4326                 }
4327                 return create_invalid_expression();
4328         }
4329
4330         declaration_t *const declaration = type_left->compound.declaration;
4331
4332         if(!declaration->init.is_defined) {
4333                 errorf(HERE, "request for member '%Y' of incomplete type '%T'",
4334                        symbol, type_left);
4335                 return create_invalid_expression();
4336         }
4337
4338         declaration_t *iter = find_compound_entry(declaration, symbol);
4339         if(iter == NULL) {
4340                 errorf(HERE, "'%T' has no member named '%Y'", orig_type, symbol);
4341                 return create_invalid_expression();
4342         }
4343
4344         /* we always do the auto-type conversions; the & and sizeof parser contains
4345          * code to revert this! */
4346         type_t *expression_type = automatic_type_conversion(iter->type);
4347
4348         select->select.compound_entry = iter;
4349         select->base.type             = expression_type;
4350
4351         if(expression_type->kind == TYPE_BITFIELD) {
4352                 expression_t *extract
4353                         = allocate_expression_zero(EXPR_UNARY_BITFIELD_EXTRACT);
4354                 extract->unary.value = select;
4355                 extract->base.type   = expression_type->bitfield.base;
4356
4357                 return extract;
4358         }
4359
4360         return select;
4361 }
4362
4363 /**
4364  * Parse a call expression, ie. expression '( ... )'.
4365  *
4366  * @param expression  the function address
4367  */
4368 static expression_t *parse_call_expression(unsigned precedence,
4369                                            expression_t *expression)
4370 {
4371         (void) precedence;
4372         expression_t *result = allocate_expression_zero(EXPR_CALL);
4373
4374         call_expression_t *call = &result->call;
4375         call->function          = expression;
4376
4377         type_t *const orig_type = expression->base.type;
4378         type_t *const type      = skip_typeref(orig_type);
4379
4380         function_type_t *function_type = NULL;
4381         if (is_type_pointer(type)) {
4382                 type_t *const to_type = skip_typeref(type->pointer.points_to);
4383
4384                 if (is_type_function(to_type)) {
4385                         function_type   = &to_type->function;
4386                         call->base.type = function_type->return_type;
4387                 }
4388         }
4389
4390         if (function_type == NULL && is_type_valid(type)) {
4391                 errorf(HERE, "called object '%E' (type '%T') is not a pointer to a function", expression, orig_type);
4392         }
4393
4394         /* parse arguments */
4395         eat('(');
4396
4397         if(token.type != ')') {
4398                 call_argument_t *last_argument = NULL;
4399
4400                 while(true) {
4401                         call_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
4402
4403                         argument->expression = parse_assignment_expression();
4404                         if(last_argument == NULL) {
4405                                 call->arguments = argument;
4406                         } else {
4407                                 last_argument->next = argument;
4408                         }
4409                         last_argument = argument;
4410
4411                         if(token.type != ',')
4412                                 break;
4413                         next_token();
4414                 }
4415         }
4416         expect(')');
4417
4418         if(function_type != NULL) {
4419                 function_parameter_t *parameter = function_type->parameters;
4420                 call_argument_t      *argument  = call->arguments;
4421                 for( ; parameter != NULL && argument != NULL;
4422                                 parameter = parameter->next, argument = argument->next) {
4423                         type_t *expected_type = parameter->type;
4424                         /* TODO report scope in error messages */
4425                         expression_t *const arg_expr = argument->expression;
4426                         type_t       *const res_type = semantic_assign(expected_type, arg_expr, "function call");
4427                         if (res_type == NULL) {
4428                                 /* TODO improve error message */
4429                                 errorf(arg_expr->base.source_position,
4430                                         "Cannot call function with argument '%E' of type '%T' where type '%T' is expected",
4431                                         arg_expr, arg_expr->base.type, expected_type);
4432                         } else {
4433                                 argument->expression = create_implicit_cast(argument->expression, expected_type);
4434                         }
4435                 }
4436                 /* too few parameters */
4437                 if(parameter != NULL) {
4438                         errorf(HERE, "too few arguments to function '%E'", expression);
4439                 } else if(argument != NULL) {
4440                         /* too many parameters */
4441                         if(!function_type->variadic
4442                                         && !function_type->unspecified_parameters) {
4443                                 errorf(HERE, "too many arguments to function '%E'", expression);
4444                         } else {
4445                                 /* do default promotion */
4446                                 for( ; argument != NULL; argument = argument->next) {
4447                                         type_t *type = argument->expression->base.type;
4448
4449                                         type = skip_typeref(type);
4450                                         if(is_type_integer(type)) {
4451                                                 type = promote_integer(type);
4452                                         } else if(type == type_float) {
4453                                                 type = type_double;
4454                                         }
4455
4456                                         argument->expression
4457                                                 = create_implicit_cast(argument->expression, type);
4458                                 }
4459
4460                                 check_format(&result->call);
4461                         }
4462                 } else {
4463                         check_format(&result->call);
4464                 }
4465         }
4466
4467         return result;
4468 }
4469
4470 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
4471
4472 static bool same_compound_type(const type_t *type1, const type_t *type2)
4473 {
4474         return
4475                 is_type_compound(type1) &&
4476                 type1->kind == type2->kind &&
4477                 type1->compound.declaration == type2->compound.declaration;
4478 }
4479
4480 /**
4481  * Parse a conditional expression, ie. 'expression ? ... : ...'.
4482  *
4483  * @param expression  the conditional expression
4484  */
4485 static expression_t *parse_conditional_expression(unsigned precedence,
4486                                                   expression_t *expression)
4487 {
4488         eat('?');
4489
4490         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
4491
4492         conditional_expression_t *conditional = &result->conditional;
4493         conditional->condition = expression;
4494
4495         /* 6.5.15.2 */
4496         type_t *const condition_type_orig = expression->base.type;
4497         type_t *const condition_type      = skip_typeref(condition_type_orig);
4498         if (!is_type_scalar(condition_type) && is_type_valid(condition_type)) {
4499                 type_error("expected a scalar type in conditional condition",
4500                            expression->base.source_position, condition_type_orig);
4501         }
4502
4503         expression_t *true_expression = parse_expression();
4504         expect(':');
4505         expression_t *false_expression = parse_sub_expression(precedence);
4506
4507         type_t *const orig_true_type  = true_expression->base.type;
4508         type_t *const orig_false_type = false_expression->base.type;
4509         type_t *const true_type       = skip_typeref(orig_true_type);
4510         type_t *const false_type      = skip_typeref(orig_false_type);
4511
4512         /* 6.5.15.3 */
4513         type_t *result_type;
4514         if (is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
4515                 result_type = semantic_arithmetic(true_type, false_type);
4516
4517                 true_expression  = create_implicit_cast(true_expression, result_type);
4518                 false_expression = create_implicit_cast(false_expression, result_type);
4519
4520                 conditional->true_expression  = true_expression;
4521                 conditional->false_expression = false_expression;
4522                 conditional->base.type        = result_type;
4523         } else if (same_compound_type(true_type, false_type) || (
4524             is_type_atomic(true_type, ATOMIC_TYPE_VOID) &&
4525             is_type_atomic(false_type, ATOMIC_TYPE_VOID)
4526                 )) {
4527                 /* just take 1 of the 2 types */
4528                 result_type = true_type;
4529         } else if (is_type_pointer(true_type) && is_type_pointer(false_type)
4530                         && pointers_compatible(true_type, false_type)) {
4531                 /* ok */
4532                 result_type = true_type;
4533         } else if (is_type_pointer(true_type)
4534                         && is_null_pointer_constant(false_expression)) {
4535                 result_type = true_type;
4536         } else if (is_type_pointer(false_type)
4537                         && is_null_pointer_constant(true_expression)) {
4538                 result_type = false_type;
4539         } else {
4540                 /* TODO: one pointer to void*, other some pointer */
4541
4542                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
4543                         type_error_incompatible("while parsing conditional",
4544                                                 expression->base.source_position, true_type,
4545                                                 false_type);
4546                 }
4547                 result_type = type_error_type;
4548         }
4549
4550         conditional->true_expression
4551                 = create_implicit_cast(true_expression, result_type);
4552         conditional->false_expression
4553                 = create_implicit_cast(false_expression, result_type);
4554         conditional->base.type = result_type;
4555         return result;
4556 }
4557
4558 /**
4559  * Parse an extension expression.
4560  */
4561 static expression_t *parse_extension(unsigned precedence)
4562 {
4563         eat(T___extension__);
4564
4565         /* TODO enable extensions */
4566         expression_t *expression = parse_sub_expression(precedence);
4567         /* TODO disable extensions */
4568         return expression;
4569 }
4570
4571 static expression_t *parse_builtin_classify_type(const unsigned precedence)
4572 {
4573         eat(T___builtin_classify_type);
4574
4575         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
4576         result->base.type    = type_int;
4577
4578         expect('(');
4579         expression_t *expression = parse_sub_expression(precedence);
4580         expect(')');
4581         result->classify_type.type_expression = expression;
4582
4583         return result;
4584 }
4585
4586 static void semantic_incdec(unary_expression_t *expression)
4587 {
4588         type_t *const orig_type = expression->value->base.type;
4589         type_t *const type      = skip_typeref(orig_type);
4590         /* TODO !is_type_real && !is_type_pointer */
4591         if(!is_type_arithmetic(type) && type->kind != TYPE_POINTER) {
4592                 if (is_type_valid(type)) {
4593                         /* TODO: improve error message */
4594                         errorf(HERE, "operation needs an arithmetic or pointer type");
4595                 }
4596                 return;
4597         }
4598
4599         expression->base.type = orig_type;
4600 }
4601
4602 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
4603 {
4604         type_t *const orig_type = expression->value->base.type;
4605         type_t *const type      = skip_typeref(orig_type);
4606         if(!is_type_arithmetic(type)) {
4607                 if (is_type_valid(type)) {
4608                         /* TODO: improve error message */
4609                         errorf(HERE, "operation needs an arithmetic type");
4610                 }
4611                 return;
4612         }
4613
4614         expression->base.type = orig_type;
4615 }
4616
4617 static void semantic_unexpr_scalar(unary_expression_t *expression)
4618 {
4619         type_t *const orig_type = expression->value->base.type;
4620         type_t *const type      = skip_typeref(orig_type);
4621         if (!is_type_scalar(type)) {
4622                 if (is_type_valid(type)) {
4623                         errorf(HERE, "operand of ! must be of scalar type");
4624                 }
4625                 return;
4626         }
4627
4628         expression->base.type = orig_type;
4629 }
4630
4631 static void semantic_unexpr_integer(unary_expression_t *expression)
4632 {
4633         type_t *const orig_type = expression->value->base.type;
4634         type_t *const type      = skip_typeref(orig_type);
4635         if (!is_type_integer(type)) {
4636                 if (is_type_valid(type)) {
4637                         errorf(HERE, "operand of ~ must be of integer type");
4638                 }
4639                 return;
4640         }
4641
4642         expression->base.type = orig_type;
4643 }
4644
4645 static void semantic_dereference(unary_expression_t *expression)
4646 {
4647         type_t *const orig_type = expression->value->base.type;
4648         type_t *const type      = skip_typeref(orig_type);
4649         if(!is_type_pointer(type)) {
4650                 if (is_type_valid(type)) {
4651                         errorf(HERE, "Unary '*' needs pointer or arrray type, but type '%T' given", orig_type);
4652                 }
4653                 return;
4654         }
4655
4656         type_t *result_type   = type->pointer.points_to;
4657         result_type           = automatic_type_conversion(result_type);
4658         expression->base.type = result_type;
4659 }
4660
4661 /**
4662  * Check the semantic of the address taken expression.
4663  */
4664 static void semantic_take_addr(unary_expression_t *expression)
4665 {
4666         expression_t *value = expression->value;
4667         value->base.type    = revert_automatic_type_conversion(value);
4668
4669         type_t *orig_type = value->base.type;
4670         if(!is_type_valid(orig_type))
4671                 return;
4672
4673         if(value->kind == EXPR_REFERENCE) {
4674                 declaration_t *const declaration = value->reference.declaration;
4675                 if(declaration != NULL) {
4676                         if (declaration->storage_class == STORAGE_CLASS_REGISTER) {
4677                                 errorf(expression->base.source_position,
4678                                         "address of register variable '%Y' requested",
4679                                         declaration->symbol);
4680                         }
4681                         declaration->address_taken = 1;
4682                 }
4683         }
4684
4685         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
4686 }
4687
4688 #define CREATE_UNARY_EXPRESSION_PARSER(token_type, unexpression_type, sfunc)   \
4689 static expression_t *parse_##unexpression_type(unsigned precedence)            \
4690 {                                                                              \
4691         eat(token_type);                                                           \
4692                                                                                    \
4693         expression_t *unary_expression                                             \
4694                 = allocate_expression_zero(unexpression_type);                         \
4695         unary_expression->base.source_position = HERE;                             \
4696         unary_expression->unary.value = parse_sub_expression(precedence);          \
4697                                                                                    \
4698         sfunc(&unary_expression->unary);                                           \
4699                                                                                    \
4700         return unary_expression;                                                   \
4701 }
4702
4703 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
4704                                semantic_unexpr_arithmetic)
4705 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
4706                                semantic_unexpr_arithmetic)
4707 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
4708                                semantic_unexpr_scalar)
4709 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
4710                                semantic_dereference)
4711 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
4712                                semantic_take_addr)
4713 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
4714                                semantic_unexpr_integer)
4715 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
4716                                semantic_incdec)
4717 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
4718                                semantic_incdec)
4719
4720 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_type, unexpression_type, \
4721                                                sfunc)                         \
4722 static expression_t *parse_##unexpression_type(unsigned precedence,           \
4723                                                expression_t *left)            \
4724 {                                                                             \
4725         (void) precedence;                                                        \
4726         eat(token_type);                                                          \
4727                                                                               \
4728         expression_t *unary_expression                                            \
4729                 = allocate_expression_zero(unexpression_type);                        \
4730         unary_expression->unary.value = left;                                     \
4731                                                                                   \
4732         sfunc(&unary_expression->unary);                                          \
4733                                                                               \
4734         return unary_expression;                                                  \
4735 }
4736
4737 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
4738                                        EXPR_UNARY_POSTFIX_INCREMENT,
4739                                        semantic_incdec)
4740 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
4741                                        EXPR_UNARY_POSTFIX_DECREMENT,
4742                                        semantic_incdec)
4743
4744 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
4745 {
4746         /* TODO: handle complex + imaginary types */
4747
4748         /* § 6.3.1.8 Usual arithmetic conversions */
4749         if(type_left == type_long_double || type_right == type_long_double) {
4750                 return type_long_double;
4751         } else if(type_left == type_double || type_right == type_double) {
4752                 return type_double;
4753         } else if(type_left == type_float || type_right == type_float) {
4754                 return type_float;
4755         }
4756
4757         type_right = promote_integer(type_right);
4758         type_left  = promote_integer(type_left);
4759
4760         if(type_left == type_right)
4761                 return type_left;
4762
4763         bool signed_left  = is_type_signed(type_left);
4764         bool signed_right = is_type_signed(type_right);
4765         int  rank_left    = get_rank(type_left);
4766         int  rank_right   = get_rank(type_right);
4767         if(rank_left < rank_right) {
4768                 if(signed_left == signed_right || !signed_right) {
4769                         return type_right;
4770                 } else {
4771                         return type_left;
4772                 }
4773         } else {
4774                 if(signed_left == signed_right || !signed_left) {
4775                         return type_left;
4776                 } else {
4777                         return type_right;
4778                 }
4779         }
4780 }
4781
4782 /**
4783  * Check the semantic restrictions for a binary expression.
4784  */
4785 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
4786 {
4787         expression_t *const left            = expression->left;
4788         expression_t *const right           = expression->right;
4789         type_t       *const orig_type_left  = left->base.type;
4790         type_t       *const orig_type_right = right->base.type;
4791         type_t       *const type_left       = skip_typeref(orig_type_left);
4792         type_t       *const type_right      = skip_typeref(orig_type_right);
4793
4794         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4795                 /* TODO: improve error message */
4796                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4797                         errorf(HERE, "operation needs arithmetic types");
4798                 }
4799                 return;
4800         }
4801
4802         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4803         expression->left      = create_implicit_cast(left, arithmetic_type);
4804         expression->right     = create_implicit_cast(right, arithmetic_type);
4805         expression->base.type = arithmetic_type;
4806 }
4807
4808 static void semantic_shift_op(binary_expression_t *expression)
4809 {
4810         expression_t *const left            = expression->left;
4811         expression_t *const right           = expression->right;
4812         type_t       *const orig_type_left  = left->base.type;
4813         type_t       *const orig_type_right = right->base.type;
4814         type_t       *      type_left       = skip_typeref(orig_type_left);
4815         type_t       *      type_right      = skip_typeref(orig_type_right);
4816
4817         if(!is_type_integer(type_left) || !is_type_integer(type_right)) {
4818                 /* TODO: improve error message */
4819                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4820                         errorf(HERE, "operation needs integer types");
4821                 }
4822                 return;
4823         }
4824
4825         type_left  = promote_integer(type_left);
4826         type_right = promote_integer(type_right);
4827
4828         expression->left      = create_implicit_cast(left, type_left);
4829         expression->right     = create_implicit_cast(right, type_right);
4830         expression->base.type = type_left;
4831 }
4832
4833 static void semantic_add(binary_expression_t *expression)
4834 {
4835         expression_t *const left            = expression->left;
4836         expression_t *const right           = expression->right;
4837         type_t       *const orig_type_left  = left->base.type;
4838         type_t       *const orig_type_right = right->base.type;
4839         type_t       *const type_left       = skip_typeref(orig_type_left);
4840         type_t       *const type_right      = skip_typeref(orig_type_right);
4841
4842         /* § 5.6.5 */
4843         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4844                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4845                 expression->left  = create_implicit_cast(left, arithmetic_type);
4846                 expression->right = create_implicit_cast(right, arithmetic_type);
4847                 expression->base.type = arithmetic_type;
4848                 return;
4849         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4850                 expression->base.type = type_left;
4851         } else if(is_type_pointer(type_right) && is_type_integer(type_left)) {
4852                 expression->base.type = type_right;
4853         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4854                 errorf(HERE, "invalid operands to binary + ('%T', '%T')", orig_type_left, orig_type_right);
4855         }
4856 }
4857
4858 static void semantic_sub(binary_expression_t *expression)
4859 {
4860         expression_t *const left            = expression->left;
4861         expression_t *const right           = expression->right;
4862         type_t       *const orig_type_left  = left->base.type;
4863         type_t       *const orig_type_right = right->base.type;
4864         type_t       *const type_left       = skip_typeref(orig_type_left);
4865         type_t       *const type_right      = skip_typeref(orig_type_right);
4866
4867         /* § 5.6.5 */
4868         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4869                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4870                 expression->left        = create_implicit_cast(left, arithmetic_type);
4871                 expression->right       = create_implicit_cast(right, arithmetic_type);
4872                 expression->base.type =  arithmetic_type;
4873                 return;
4874         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4875                 expression->base.type = type_left;
4876         } else if(is_type_pointer(type_left) && is_type_pointer(type_right)) {
4877                 if(!pointers_compatible(type_left, type_right)) {
4878                         errorf(HERE,
4879                                "pointers to incompatible objects to binary '-' ('%T', '%T')",
4880                                orig_type_left, orig_type_right);
4881                 } else {
4882                         expression->base.type = type_ptrdiff_t;
4883                 }
4884         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4885                 errorf(HERE, "invalid operands to binary '-' ('%T', '%T')",
4886                        orig_type_left, orig_type_right);
4887         }
4888 }
4889
4890 /**
4891  * Check the semantics of comparison expressions.
4892  *
4893  * @param expression   The expression to check.
4894  */
4895 static void semantic_comparison(binary_expression_t *expression)
4896 {
4897         expression_t *left            = expression->left;
4898         expression_t *right           = expression->right;
4899         type_t       *orig_type_left  = left->base.type;
4900         type_t       *orig_type_right = right->base.type;
4901
4902         type_t *type_left  = skip_typeref(orig_type_left);
4903         type_t *type_right = skip_typeref(orig_type_right);
4904
4905         /* TODO non-arithmetic types */
4906         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4907                 if (warning.sign_compare &&
4908                     (expression->base.kind != EXPR_BINARY_EQUAL &&
4909                      expression->base.kind != EXPR_BINARY_NOTEQUAL) &&
4910                     (is_type_signed(type_left) != is_type_signed(type_right))) {
4911                         warningf(expression->base.source_position,
4912                                  "comparison between signed and unsigned");
4913                 }
4914                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4915                 expression->left        = create_implicit_cast(left, arithmetic_type);
4916                 expression->right       = create_implicit_cast(right, arithmetic_type);
4917                 expression->base.type   = arithmetic_type;
4918                 if (warning.float_equal &&
4919                     (expression->base.kind == EXPR_BINARY_EQUAL ||
4920                      expression->base.kind == EXPR_BINARY_NOTEQUAL) &&
4921                     is_type_float(arithmetic_type)) {
4922                         warningf(expression->base.source_position,
4923                                  "comparing floating point with == or != is unsafe");
4924                 }
4925         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
4926                 /* TODO check compatibility */
4927         } else if (is_type_pointer(type_left)) {
4928                 expression->right = create_implicit_cast(right, type_left);
4929         } else if (is_type_pointer(type_right)) {
4930                 expression->left = create_implicit_cast(left, type_right);
4931         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4932                 type_error_incompatible("invalid operands in comparison",
4933                                         expression->base.source_position,
4934                                         type_left, type_right);
4935         }
4936         expression->base.type = type_int;
4937 }
4938
4939 static void semantic_arithmetic_assign(binary_expression_t *expression)
4940 {
4941         expression_t *left            = expression->left;
4942         expression_t *right           = expression->right;
4943         type_t       *orig_type_left  = left->base.type;
4944         type_t       *orig_type_right = right->base.type;
4945
4946         type_t *type_left  = skip_typeref(orig_type_left);
4947         type_t *type_right = skip_typeref(orig_type_right);
4948
4949         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4950                 /* TODO: improve error message */
4951                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4952                         errorf(HERE, "operation needs arithmetic types");
4953                 }
4954                 return;
4955         }
4956
4957         /* combined instructions are tricky. We can't create an implicit cast on
4958          * the left side, because we need the uncasted form for the store.
4959          * The ast2firm pass has to know that left_type must be right_type
4960          * for the arithmetic operation and create a cast by itself */
4961         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4962         expression->right       = create_implicit_cast(right, arithmetic_type);
4963         expression->base.type   = type_left;
4964 }
4965
4966 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
4967 {
4968         expression_t *const left            = expression->left;
4969         expression_t *const right           = expression->right;
4970         type_t       *const orig_type_left  = left->base.type;
4971         type_t       *const orig_type_right = right->base.type;
4972         type_t       *const type_left       = skip_typeref(orig_type_left);
4973         type_t       *const type_right      = skip_typeref(orig_type_right);
4974
4975         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4976                 /* combined instructions are tricky. We can't create an implicit cast on
4977                  * the left side, because we need the uncasted form for the store.
4978                  * The ast2firm pass has to know that left_type must be right_type
4979                  * for the arithmetic operation and create a cast by itself */
4980                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
4981                 expression->right     = create_implicit_cast(right, arithmetic_type);
4982                 expression->base.type = type_left;
4983         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
4984                 expression->base.type = type_left;
4985         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4986                 errorf(HERE, "incompatible types '%T' and '%T' in assignment", orig_type_left, orig_type_right);
4987         }
4988 }
4989
4990 /**
4991  * Check the semantic restrictions of a logical expression.
4992  */
4993 static void semantic_logical_op(binary_expression_t *expression)
4994 {
4995         expression_t *const left            = expression->left;
4996         expression_t *const right           = expression->right;
4997         type_t       *const orig_type_left  = left->base.type;
4998         type_t       *const orig_type_right = right->base.type;
4999         type_t       *const type_left       = skip_typeref(orig_type_left);
5000         type_t       *const type_right      = skip_typeref(orig_type_right);
5001
5002         if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
5003                 /* TODO: improve error message */
5004                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
5005                         errorf(HERE, "operation needs scalar types");
5006                 }
5007                 return;
5008         }
5009
5010         expression->base.type = type_int;
5011 }
5012
5013 /**
5014  * Checks if a compound type has constant fields.
5015  */
5016 static bool has_const_fields(const compound_type_t *type)
5017 {
5018         const scope_t       *scope       = &type->declaration->scope;
5019         const declaration_t *declaration = scope->declarations;
5020
5021         for (; declaration != NULL; declaration = declaration->next) {
5022                 if (declaration->namespc != NAMESPACE_NORMAL)
5023                         continue;
5024
5025                 const type_t *decl_type = skip_typeref(declaration->type);
5026                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
5027                         return true;
5028         }
5029         /* TODO */
5030         return false;
5031 }
5032
5033 /**
5034  * Check the semantic restrictions of a binary assign expression.
5035  */
5036 static void semantic_binexpr_assign(binary_expression_t *expression)
5037 {
5038         expression_t *left           = expression->left;
5039         type_t       *orig_type_left = left->base.type;
5040
5041         type_t *type_left = revert_automatic_type_conversion(left);
5042         type_left         = skip_typeref(orig_type_left);
5043
5044         /* must be a modifiable lvalue */
5045         if (is_type_array(type_left)) {
5046                 errorf(HERE, "cannot assign to arrays ('%E')", left);
5047                 return;
5048         }
5049         if(type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
5050                 errorf(HERE, "assignment to readonly location '%E' (type '%T')", left,
5051                        orig_type_left);
5052                 return;
5053         }
5054         if(is_type_incomplete(type_left)) {
5055                 errorf(HERE,
5056                        "left-hand side of assignment '%E' has incomplete type '%T'",
5057                        left, orig_type_left);
5058                 return;
5059         }
5060         if(is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
5061                 errorf(HERE, "cannot assign to '%E' because compound type '%T' has readonly fields",
5062                        left, orig_type_left);
5063                 return;
5064         }
5065
5066         type_t *const res_type = semantic_assign(orig_type_left, expression->right,
5067                                                  "assignment");
5068         if (res_type == NULL) {
5069                 errorf(expression->base.source_position,
5070                         "cannot assign to '%T' from '%T'",
5071                         orig_type_left, expression->right->base.type);
5072         } else {
5073                 expression->right = create_implicit_cast(expression->right, res_type);
5074         }
5075
5076         expression->base.type = orig_type_left;
5077 }
5078
5079 static bool expression_has_effect(const expression_t *const expr)
5080 {
5081         switch (expr->kind) {
5082                 case EXPR_UNKNOWN:                   break;
5083                 case EXPR_INVALID:                   break;
5084                 case EXPR_REFERENCE:                 return false;
5085                 case EXPR_CONST:                     return false;
5086                 case EXPR_CHAR_CONST:                return false;
5087                 case EXPR_STRING_LITERAL:            return false;
5088                 case EXPR_WIDE_STRING_LITERAL:       return false;
5089                 case EXPR_CALL: {
5090                         const call_expression_t *const call = &expr->call;
5091                         if (call->function->kind != EXPR_BUILTIN_SYMBOL)
5092                                 return true;
5093
5094                         switch (call->function->builtin_symbol.symbol->ID) {
5095                                 case T___builtin_va_end: return true;
5096                                 default:                 return false;
5097                         }
5098                 }
5099                 case EXPR_CONDITIONAL: {
5100                         const conditional_expression_t *const cond = &expr->conditional;
5101                         return
5102                                 expression_has_effect(cond->true_expression) &&
5103                                 expression_has_effect(cond->false_expression);
5104                 }
5105                 case EXPR_SELECT:                    return false;
5106                 case EXPR_ARRAY_ACCESS:              return false;
5107                 case EXPR_SIZEOF:                    return false;
5108                 case EXPR_CLASSIFY_TYPE:             return false;
5109                 case EXPR_ALIGNOF:                   return false;
5110
5111                 case EXPR_FUNCTION:                  return false;
5112                 case EXPR_PRETTY_FUNCTION:           return false;
5113                 case EXPR_BUILTIN_SYMBOL:            break; /* handled in EXPR_CALL */
5114                 case EXPR_BUILTIN_CONSTANT_P:        return false;
5115                 case EXPR_BUILTIN_PREFETCH:          return true;
5116                 case EXPR_OFFSETOF:                  return false;
5117                 case EXPR_VA_START:                  return true;
5118                 case EXPR_VA_ARG:                    return true;
5119                 case EXPR_STATEMENT:                 return true; // TODO
5120                 case EXPR_COMPOUND_LITERAL:          return false;
5121
5122                 case EXPR_UNARY_NEGATE:              return false;
5123                 case EXPR_UNARY_PLUS:                return false;
5124                 case EXPR_UNARY_BITWISE_NEGATE:      return false;
5125                 case EXPR_UNARY_NOT:                 return false;
5126                 case EXPR_UNARY_DEREFERENCE:         return false;
5127                 case EXPR_UNARY_TAKE_ADDRESS:        return false;
5128                 case EXPR_UNARY_POSTFIX_INCREMENT:   return true;
5129                 case EXPR_UNARY_POSTFIX_DECREMENT:   return true;
5130                 case EXPR_UNARY_PREFIX_INCREMENT:    return true;
5131                 case EXPR_UNARY_PREFIX_DECREMENT:    return true;
5132                 case EXPR_UNARY_CAST: {
5133                         type_t *type = skip_typeref(expr->base.type);
5134                         return is_type_atomic(type, ATOMIC_TYPE_VOID);
5135                 }
5136                 case EXPR_UNARY_CAST_IMPLICIT:       return true;
5137                 case EXPR_UNARY_ASSUME:              return true;
5138                 case EXPR_UNARY_BITFIELD_EXTRACT:    return false;
5139
5140                 case EXPR_BINARY_ADD:                return false;
5141                 case EXPR_BINARY_SUB:                return false;
5142                 case EXPR_BINARY_MUL:                return false;
5143                 case EXPR_BINARY_DIV:                return false;
5144                 case EXPR_BINARY_MOD:                return false;
5145                 case EXPR_BINARY_EQUAL:              return false;
5146                 case EXPR_BINARY_NOTEQUAL:           return false;
5147                 case EXPR_BINARY_LESS:               return false;
5148                 case EXPR_BINARY_LESSEQUAL:          return false;
5149                 case EXPR_BINARY_GREATER:            return false;
5150                 case EXPR_BINARY_GREATEREQUAL:       return false;
5151                 case EXPR_BINARY_BITWISE_AND:        return false;
5152                 case EXPR_BINARY_BITWISE_OR:         return false;
5153                 case EXPR_BINARY_BITWISE_XOR:        return false;
5154                 case EXPR_BINARY_SHIFTLEFT:          return false;
5155                 case EXPR_BINARY_SHIFTRIGHT:         return false;
5156                 case EXPR_BINARY_ASSIGN:             return true;
5157                 case EXPR_BINARY_MUL_ASSIGN:         return true;
5158                 case EXPR_BINARY_DIV_ASSIGN:         return true;
5159                 case EXPR_BINARY_MOD_ASSIGN:         return true;
5160                 case EXPR_BINARY_ADD_ASSIGN:         return true;
5161                 case EXPR_BINARY_SUB_ASSIGN:         return true;
5162                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:   return true;
5163                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:  return true;
5164                 case EXPR_BINARY_BITWISE_AND_ASSIGN: return true;
5165                 case EXPR_BINARY_BITWISE_XOR_ASSIGN: return true;
5166                 case EXPR_BINARY_BITWISE_OR_ASSIGN:  return true;
5167                 case EXPR_BINARY_LOGICAL_AND:
5168                 case EXPR_BINARY_LOGICAL_OR:
5169                 case EXPR_BINARY_COMMA:
5170                         return expression_has_effect(expr->binary.right);
5171
5172                 case EXPR_BINARY_BUILTIN_EXPECT:     return true;
5173                 case EXPR_BINARY_ISGREATER:          return false;
5174                 case EXPR_BINARY_ISGREATEREQUAL:     return false;
5175                 case EXPR_BINARY_ISLESS:             return false;
5176                 case EXPR_BINARY_ISLESSEQUAL:        return false;
5177                 case EXPR_BINARY_ISLESSGREATER:      return false;
5178                 case EXPR_BINARY_ISUNORDERED:        return false;
5179         }
5180
5181         panic("unexpected statement");
5182 }
5183
5184 static void semantic_comma(binary_expression_t *expression)
5185 {
5186         if (warning.unused_value) {
5187                 const expression_t *const left = expression->left;
5188                 if (!expression_has_effect(left)) {
5189                         warningf(left->base.source_position, "left-hand operand of comma expression has no effect");
5190                 }
5191         }
5192         expression->base.type = expression->right->base.type;
5193 }
5194
5195 #define CREATE_BINEXPR_PARSER(token_type, binexpression_type, sfunc, lr)  \
5196 static expression_t *parse_##binexpression_type(unsigned precedence,      \
5197                                                 expression_t *left)       \
5198 {                                                                         \
5199         eat(token_type);                                                      \
5200         source_position_t pos = HERE;                                         \
5201                                                                           \
5202         expression_t *right = parse_sub_expression(precedence + lr);          \
5203                                                                           \
5204         expression_t *binexpr = allocate_expression_zero(binexpression_type); \
5205         binexpr->base.source_position = pos;                                  \
5206         binexpr->binary.left  = left;                                         \
5207         binexpr->binary.right = right;                                        \
5208         sfunc(&binexpr->binary);                                              \
5209                                                                           \
5210         return binexpr;                                                       \
5211 }
5212
5213 CREATE_BINEXPR_PARSER(',', EXPR_BINARY_COMMA,    semantic_comma, 1)
5214 CREATE_BINEXPR_PARSER('*', EXPR_BINARY_MUL,      semantic_binexpr_arithmetic, 1)
5215 CREATE_BINEXPR_PARSER('/', EXPR_BINARY_DIV,      semantic_binexpr_arithmetic, 1)
5216 CREATE_BINEXPR_PARSER('%', EXPR_BINARY_MOD,      semantic_binexpr_arithmetic, 1)
5217 CREATE_BINEXPR_PARSER('+', EXPR_BINARY_ADD,      semantic_add, 1)
5218 CREATE_BINEXPR_PARSER('-', EXPR_BINARY_SUB,      semantic_sub, 1)
5219 CREATE_BINEXPR_PARSER('<', EXPR_BINARY_LESS,     semantic_comparison, 1)
5220 CREATE_BINEXPR_PARSER('>', EXPR_BINARY_GREATER,  semantic_comparison, 1)
5221 CREATE_BINEXPR_PARSER('=', EXPR_BINARY_ASSIGN,   semantic_binexpr_assign, 0)
5222
5223 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,
5224                       semantic_comparison, 1)
5225 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,
5226                       semantic_comparison, 1)
5227 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,
5228                       semantic_comparison, 1)
5229 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,
5230                       semantic_comparison, 1)
5231
5232 CREATE_BINEXPR_PARSER('&', EXPR_BINARY_BITWISE_AND,
5233                       semantic_binexpr_arithmetic, 1)
5234 CREATE_BINEXPR_PARSER('|', EXPR_BINARY_BITWISE_OR,
5235                       semantic_binexpr_arithmetic, 1)
5236 CREATE_BINEXPR_PARSER('^', EXPR_BINARY_BITWISE_XOR,
5237                       semantic_binexpr_arithmetic, 1)
5238 CREATE_BINEXPR_PARSER(T_ANDAND, EXPR_BINARY_LOGICAL_AND,
5239                       semantic_logical_op, 1)
5240 CREATE_BINEXPR_PARSER(T_PIPEPIPE, EXPR_BINARY_LOGICAL_OR,
5241                       semantic_logical_op, 1)
5242 CREATE_BINEXPR_PARSER(T_LESSLESS, EXPR_BINARY_SHIFTLEFT,
5243                       semantic_shift_op, 1)
5244 CREATE_BINEXPR_PARSER(T_GREATERGREATER, EXPR_BINARY_SHIFTRIGHT,
5245                       semantic_shift_op, 1)
5246 CREATE_BINEXPR_PARSER(T_PLUSEQUAL, EXPR_BINARY_ADD_ASSIGN,
5247                       semantic_arithmetic_addsubb_assign, 0)
5248 CREATE_BINEXPR_PARSER(T_MINUSEQUAL, EXPR_BINARY_SUB_ASSIGN,
5249                       semantic_arithmetic_addsubb_assign, 0)
5250 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL, EXPR_BINARY_MUL_ASSIGN,
5251                       semantic_arithmetic_assign, 0)
5252 CREATE_BINEXPR_PARSER(T_SLASHEQUAL, EXPR_BINARY_DIV_ASSIGN,
5253                       semantic_arithmetic_assign, 0)
5254 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL, EXPR_BINARY_MOD_ASSIGN,
5255                       semantic_arithmetic_assign, 0)
5256 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL, EXPR_BINARY_SHIFTLEFT_ASSIGN,
5257                       semantic_arithmetic_assign, 0)
5258 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL, EXPR_BINARY_SHIFTRIGHT_ASSIGN,
5259                       semantic_arithmetic_assign, 0)
5260 CREATE_BINEXPR_PARSER(T_ANDEQUAL, EXPR_BINARY_BITWISE_AND_ASSIGN,
5261                       semantic_arithmetic_assign, 0)
5262 CREATE_BINEXPR_PARSER(T_PIPEEQUAL, EXPR_BINARY_BITWISE_OR_ASSIGN,
5263                       semantic_arithmetic_assign, 0)
5264 CREATE_BINEXPR_PARSER(T_CARETEQUAL, EXPR_BINARY_BITWISE_XOR_ASSIGN,
5265                       semantic_arithmetic_assign, 0)
5266
5267 static expression_t *parse_sub_expression(unsigned precedence)
5268 {
5269         if(token.type < 0) {
5270                 return expected_expression_error();
5271         }
5272
5273         expression_parser_function_t *parser
5274                 = &expression_parsers[token.type];
5275         source_position_t             source_position = token.source_position;
5276         expression_t                 *left;
5277
5278         if(parser->parser != NULL) {
5279                 left = parser->parser(parser->precedence);
5280         } else {
5281                 left = parse_primary_expression();
5282         }
5283         assert(left != NULL);
5284         left->base.source_position = source_position;
5285
5286         while(true) {
5287                 if(token.type < 0) {
5288                         return expected_expression_error();
5289                 }
5290
5291                 parser = &expression_parsers[token.type];
5292                 if(parser->infix_parser == NULL)
5293                         break;
5294                 if(parser->infix_precedence < precedence)
5295                         break;
5296
5297                 left = parser->infix_parser(parser->infix_precedence, left);
5298
5299                 assert(left != NULL);
5300                 assert(left->kind != EXPR_UNKNOWN);
5301                 left->base.source_position = source_position;
5302         }
5303
5304         return left;
5305 }
5306
5307 /**
5308  * Parse an expression.
5309  */
5310 static expression_t *parse_expression(void)
5311 {
5312         return parse_sub_expression(1);
5313 }
5314
5315 /**
5316  * Register a parser for a prefix-like operator with given precedence.
5317  *
5318  * @param parser      the parser function
5319  * @param token_type  the token type of the prefix token
5320  * @param precedence  the precedence of the operator
5321  */
5322 static void register_expression_parser(parse_expression_function parser,
5323                                        int token_type, unsigned precedence)
5324 {
5325         expression_parser_function_t *entry = &expression_parsers[token_type];
5326
5327         if(entry->parser != NULL) {
5328                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
5329                 panic("trying to register multiple expression parsers for a token");
5330         }
5331         entry->parser     = parser;
5332         entry->precedence = precedence;
5333 }
5334
5335 /**
5336  * Register a parser for an infix operator with given precedence.
5337  *
5338  * @param parser      the parser function
5339  * @param token_type  the token type of the infix operator
5340  * @param precedence  the precedence of the operator
5341  */
5342 static void register_infix_parser(parse_expression_infix_function parser,
5343                 int token_type, unsigned precedence)
5344 {
5345         expression_parser_function_t *entry = &expression_parsers[token_type];
5346
5347         if(entry->infix_parser != NULL) {
5348                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
5349                 panic("trying to register multiple infix expression parsers for a "
5350                       "token");
5351         }
5352         entry->infix_parser     = parser;
5353         entry->infix_precedence = precedence;
5354 }
5355
5356 /**
5357  * Initialize the expression parsers.
5358  */
5359 static void init_expression_parsers(void)
5360 {
5361         memset(&expression_parsers, 0, sizeof(expression_parsers));
5362
5363         register_infix_parser(parse_array_expression,         '[',              30);
5364         register_infix_parser(parse_call_expression,          '(',              30);
5365         register_infix_parser(parse_select_expression,        '.',              30);
5366         register_infix_parser(parse_select_expression,        T_MINUSGREATER,   30);
5367         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,
5368                                                               T_PLUSPLUS,       30);
5369         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,
5370                                                               T_MINUSMINUS,     30);
5371
5372         register_infix_parser(parse_EXPR_BINARY_MUL,          '*',              16);
5373         register_infix_parser(parse_EXPR_BINARY_DIV,          '/',              16);
5374         register_infix_parser(parse_EXPR_BINARY_MOD,          '%',              16);
5375         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,    T_LESSLESS,       16);
5376         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,   T_GREATERGREATER, 16);
5377         register_infix_parser(parse_EXPR_BINARY_ADD,          '+',              15);
5378         register_infix_parser(parse_EXPR_BINARY_SUB,          '-',              15);
5379         register_infix_parser(parse_EXPR_BINARY_LESS,         '<',              14);
5380         register_infix_parser(parse_EXPR_BINARY_GREATER,      '>',              14);
5381         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,    T_LESSEQUAL,      14);
5382         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL, T_GREATEREQUAL,   14);
5383         register_infix_parser(parse_EXPR_BINARY_EQUAL,        T_EQUALEQUAL,     13);
5384         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,
5385                                                     T_EXCLAMATIONMARKEQUAL, 13);
5386         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,  '&',              12);
5387         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,  '^',              11);
5388         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,   '|',              10);
5389         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,  T_ANDAND,          9);
5390         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,   T_PIPEPIPE,        8);
5391         register_infix_parser(parse_conditional_expression,   '?',               7);
5392         register_infix_parser(parse_EXPR_BINARY_ASSIGN,       '=',               2);
5393         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,   T_PLUSEQUAL,       2);
5394         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,   T_MINUSEQUAL,      2);
5395         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,   T_ASTERISKEQUAL,   2);
5396         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,   T_SLASHEQUAL,      2);
5397         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,   T_PERCENTEQUAL,    2);
5398         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,
5399                                                                 T_LESSLESSEQUAL, 2);
5400         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,
5401                                                           T_GREATERGREATEREQUAL, 2);
5402         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN,
5403                                                                      T_ANDEQUAL, 2);
5404         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,
5405                                                                     T_PIPEEQUAL, 2);
5406         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN,
5407                                                                    T_CARETEQUAL, 2);
5408
5409         register_infix_parser(parse_EXPR_BINARY_COMMA,        ',',               1);
5410
5411         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-',      25);
5412         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+',      25);
5413         register_expression_parser(parse_EXPR_UNARY_NOT,              '!',      25);
5414         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~',      25);
5415         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*',      25);
5416         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&',      25);
5417         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT,
5418                                                                   T_PLUSPLUS,   25);
5419         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT,
5420                                                                   T_MINUSMINUS, 25);
5421         register_expression_parser(parse_sizeof,                      T_sizeof, 25);
5422         register_expression_parser(parse_alignof,                T___alignof__, 25);
5423         register_expression_parser(parse_extension,            T___extension__, 25);
5424         register_expression_parser(parse_builtin_classify_type,
5425                                                      T___builtin_classify_type, 25);
5426 }
5427
5428 /**
5429  * Parse a asm statement constraints specification.
5430  */
5431 static asm_constraint_t *parse_asm_constraints(void)
5432 {
5433         asm_constraint_t *result = NULL;
5434         asm_constraint_t *last   = NULL;
5435
5436         while(token.type == T_STRING_LITERAL || token.type == '[') {
5437                 asm_constraint_t *constraint = allocate_ast_zero(sizeof(constraint[0]));
5438                 memset(constraint, 0, sizeof(constraint[0]));
5439
5440                 if(token.type == '[') {
5441                         eat('[');
5442                         if(token.type != T_IDENTIFIER) {
5443                                 parse_error_expected("while parsing asm constraint",
5444                                                      T_IDENTIFIER, 0);
5445                                 return NULL;
5446                         }
5447                         constraint->symbol = token.v.symbol;
5448
5449                         expect(']');
5450                 }
5451
5452                 constraint->constraints = parse_string_literals();
5453                 expect('(');
5454                 constraint->expression = parse_expression();
5455                 expect(')');
5456
5457                 if(last != NULL) {
5458                         last->next = constraint;
5459                 } else {
5460                         result = constraint;
5461                 }
5462                 last = constraint;
5463
5464                 if(token.type != ',')
5465                         break;
5466                 eat(',');
5467         }
5468
5469         return result;
5470 }
5471
5472 /**
5473  * Parse a asm statement clobber specification.
5474  */
5475 static asm_clobber_t *parse_asm_clobbers(void)
5476 {
5477         asm_clobber_t *result = NULL;
5478         asm_clobber_t *last   = NULL;
5479
5480         while(token.type == T_STRING_LITERAL) {
5481                 asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
5482                 clobber->clobber       = parse_string_literals();
5483
5484                 if(last != NULL) {
5485                         last->next = clobber;
5486                 } else {
5487                         result = clobber;
5488                 }
5489                 last = clobber;
5490
5491                 if(token.type != ',')
5492                         break;
5493                 eat(',');
5494         }
5495
5496         return result;
5497 }
5498
5499 /**
5500  * Parse an asm statement.
5501  */
5502 static statement_t *parse_asm_statement(void)
5503 {
5504         eat(T_asm);
5505
5506         statement_t *statement          = allocate_statement_zero(STATEMENT_ASM);
5507         statement->base.source_position = token.source_position;
5508
5509         asm_statement_t *asm_statement = &statement->asms;
5510
5511         if(token.type == T_volatile) {
5512                 next_token();
5513                 asm_statement->is_volatile = true;
5514         }
5515
5516         expect('(');
5517         asm_statement->asm_text = parse_string_literals();
5518
5519         if(token.type != ':')
5520                 goto end_of_asm;
5521         eat(':');
5522
5523         asm_statement->inputs = parse_asm_constraints();
5524         if(token.type != ':')
5525                 goto end_of_asm;
5526         eat(':');
5527
5528         asm_statement->outputs = parse_asm_constraints();
5529         if(token.type != ':')
5530                 goto end_of_asm;
5531         eat(':');
5532
5533         asm_statement->clobbers = parse_asm_clobbers();
5534
5535 end_of_asm:
5536         expect(')');
5537         expect(';');
5538         return statement;
5539 }
5540
5541 /**
5542  * Parse a case statement.
5543  */
5544 static statement_t *parse_case_statement(void)
5545 {
5546         eat(T_case);
5547
5548         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
5549
5550         statement->base.source_position  = token.source_position;
5551         statement->case_label.expression = parse_expression();
5552
5553         if (c_mode & _GNUC) {
5554                 if (token.type == T_DOTDOTDOT) {
5555                         next_token();
5556                         statement->case_label.end_range = parse_expression();
5557                 }
5558         }
5559
5560         expect(':');
5561
5562         if (! is_constant_expression(statement->case_label.expression)) {
5563                 errorf(statement->base.source_position,
5564                         "case label does not reduce to an integer constant");
5565         } else {
5566                 /* TODO: check if the case label is already known */
5567                 if (current_switch != NULL) {
5568                         /* link all cases into the switch statement */
5569                         if (current_switch->last_case == NULL) {
5570                                 current_switch->first_case =
5571                                 current_switch->last_case  = &statement->case_label;
5572                         } else {
5573                                 current_switch->last_case->next = &statement->case_label;
5574                         }
5575                 } else {
5576                         errorf(statement->base.source_position,
5577                                 "case label not within a switch statement");
5578                 }
5579         }
5580         statement->case_label.statement = parse_statement();
5581
5582         return statement;
5583 }
5584
5585 /**
5586  * Finds an existing default label of a switch statement.
5587  */
5588 static case_label_statement_t *
5589 find_default_label(const switch_statement_t *statement)
5590 {
5591         case_label_statement_t *label = statement->first_case;
5592         for ( ; label != NULL; label = label->next) {
5593                 if (label->expression == NULL)
5594                         return label;
5595         }
5596         return NULL;
5597 }
5598
5599 /**
5600  * Parse a default statement.
5601  */
5602 static statement_t *parse_default_statement(void)
5603 {
5604         eat(T_default);
5605
5606         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
5607
5608         statement->base.source_position = token.source_position;
5609
5610         expect(':');
5611         if (current_switch != NULL) {
5612                 const case_label_statement_t *def_label = find_default_label(current_switch);
5613                 if (def_label != NULL) {
5614                         errorf(HERE, "multiple default labels in one switch");
5615                         errorf(def_label->base.source_position,
5616                                 "this is the first default label");
5617                 } else {
5618                         /* link all cases into the switch statement */
5619                         if (current_switch->last_case == NULL) {
5620                                 current_switch->first_case =
5621                                         current_switch->last_case  = &statement->case_label;
5622                         } else {
5623                                 current_switch->last_case->next = &statement->case_label;
5624                         }
5625                 }
5626         } else {
5627                 errorf(statement->base.source_position,
5628                         "'default' label not within a switch statement");
5629         }
5630         statement->case_label.statement = parse_statement();
5631
5632         return statement;
5633 }
5634
5635 /**
5636  * Return the declaration for a given label symbol or create a new one.
5637  */
5638 static declaration_t *get_label(symbol_t *symbol)
5639 {
5640         declaration_t *candidate = get_declaration(symbol, NAMESPACE_LABEL);
5641         assert(current_function != NULL);
5642         /* if we found a label in the same function, then we already created the
5643          * declaration */
5644         if(candidate != NULL
5645                         && candidate->parent_scope == &current_function->scope) {
5646                 return candidate;
5647         }
5648
5649         /* otherwise we need to create a new one */
5650         declaration_t *const declaration = allocate_declaration_zero();
5651         declaration->namespc       = NAMESPACE_LABEL;
5652         declaration->symbol        = symbol;
5653
5654         label_push(declaration);
5655
5656         return declaration;
5657 }
5658
5659 /**
5660  * Parse a label statement.
5661  */
5662 static statement_t *parse_label_statement(void)
5663 {
5664         assert(token.type == T_IDENTIFIER);
5665         symbol_t *symbol = token.v.symbol;
5666         next_token();
5667
5668         declaration_t *label = get_label(symbol);
5669
5670         /* if source position is already set then the label is defined twice,
5671          * otherwise it was just mentioned in a goto so far */
5672         if(label->source_position.input_name != NULL) {
5673                 errorf(HERE, "duplicate label '%Y'", symbol);
5674                 errorf(label->source_position, "previous definition of '%Y' was here",
5675                        symbol);
5676         } else {
5677                 label->source_position = token.source_position;
5678         }
5679
5680         statement_t *statement = allocate_statement_zero(STATEMENT_LABEL);
5681
5682         statement->base.source_position = token.source_position;
5683         statement->label.label          = label;
5684
5685         eat(':');
5686
5687         if(token.type == '}') {
5688                 /* TODO only warn? */
5689                 errorf(HERE, "label at end of compound statement");
5690                 return statement;
5691         } else {
5692                 if (token.type == ';') {
5693                         /* eat an empty statement here, to avoid the warning about an empty
5694                          * after a label.  label:; is commonly used to have a label before
5695                          * a }. */
5696                         next_token();
5697                 } else {
5698                         statement->label.statement = parse_statement();
5699                 }
5700         }
5701
5702         /* remember the labels's in a list for later checking */
5703         if (label_last == NULL) {
5704                 label_first = &statement->label;
5705         } else {
5706                 label_last->next = &statement->label;
5707         }
5708         label_last = &statement->label;
5709
5710         return statement;
5711 }
5712
5713 /**
5714  * Parse an if statement.
5715  */
5716 static statement_t *parse_if(void)
5717 {
5718         eat(T_if);
5719
5720         statement_t *statement          = allocate_statement_zero(STATEMENT_IF);
5721         statement->base.source_position = token.source_position;
5722
5723         expect('(');
5724         statement->ifs.condition = parse_expression();
5725         expect(')');
5726
5727         statement->ifs.true_statement = parse_statement();
5728         if(token.type == T_else) {
5729                 next_token();
5730                 statement->ifs.false_statement = parse_statement();
5731         }
5732
5733         return statement;
5734 }
5735
5736 /**
5737  * Parse a switch statement.
5738  */
5739 static statement_t *parse_switch(void)
5740 {
5741         eat(T_switch);
5742
5743         statement_t *statement          = allocate_statement_zero(STATEMENT_SWITCH);
5744         statement->base.source_position = token.source_position;
5745
5746         expect('(');
5747         expression_t *const expr = parse_expression();
5748         type_t       *      type = skip_typeref(expr->base.type);
5749         if (is_type_integer(type)) {
5750                 type = promote_integer(type);
5751         } else if (is_type_valid(type)) {
5752                 errorf(expr->base.source_position,
5753                        "switch quantity is not an integer, but '%T'", type);
5754                 type = type_error_type;
5755         }
5756         statement->switchs.expression = create_implicit_cast(expr, type);
5757         expect(')');
5758
5759         switch_statement_t *rem = current_switch;
5760         current_switch          = &statement->switchs;
5761         statement->switchs.body = parse_statement();
5762         current_switch          = rem;
5763
5764         if (warning.switch_default
5765                         && find_default_label(&statement->switchs) == NULL) {
5766                 warningf(statement->base.source_position, "switch has no default case");
5767         }
5768
5769         return statement;
5770 }
5771
5772 static statement_t *parse_loop_body(statement_t *const loop)
5773 {
5774         statement_t *const rem = current_loop;
5775         current_loop = loop;
5776
5777         statement_t *const body = parse_statement();
5778
5779         current_loop = rem;
5780         return body;
5781 }
5782
5783 /**
5784  * Parse a while statement.
5785  */
5786 static statement_t *parse_while(void)
5787 {
5788         eat(T_while);
5789
5790         statement_t *statement          = allocate_statement_zero(STATEMENT_WHILE);
5791         statement->base.source_position = token.source_position;
5792
5793         expect('(');
5794         statement->whiles.condition = parse_expression();
5795         expect(')');
5796
5797         statement->whiles.body = parse_loop_body(statement);
5798
5799         return statement;
5800 }
5801
5802 /**
5803  * Parse a do statement.
5804  */
5805 static statement_t *parse_do(void)
5806 {
5807         eat(T_do);
5808
5809         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
5810
5811         statement->base.source_position = token.source_position;
5812
5813         statement->do_while.body = parse_loop_body(statement);
5814
5815         expect(T_while);
5816         expect('(');
5817         statement->do_while.condition = parse_expression();
5818         expect(')');
5819         expect(';');
5820
5821         return statement;
5822 }
5823
5824 /**
5825  * Parse a for statement.
5826  */
5827 static statement_t *parse_for(void)
5828 {
5829         eat(T_for);
5830
5831         statement_t *statement          = allocate_statement_zero(STATEMENT_FOR);
5832         statement->base.source_position = token.source_position;
5833
5834         expect('(');
5835
5836         int      top        = environment_top();
5837         scope_t *last_scope = scope;
5838         set_scope(&statement->fors.scope);
5839
5840         if(token.type != ';') {
5841                 if(is_declaration_specifier(&token, false)) {
5842                         parse_declaration(record_declaration);
5843                 } else {
5844                         expression_t *const init = parse_expression();
5845                         statement->fors.initialisation = init;
5846                         if (warning.unused_value  && !expression_has_effect(init)) {
5847                                 warningf(init->base.source_position, "initialisation of 'for'-statement has no effect");
5848                         }
5849                         expect(';');
5850                 }
5851         } else {
5852                 expect(';');
5853         }
5854
5855         if(token.type != ';') {
5856                 statement->fors.condition = parse_expression();
5857         }
5858         expect(';');
5859         if(token.type != ')') {
5860                 expression_t *const step = parse_expression();
5861                 statement->fors.step = step;
5862                 if (warning.unused_value  && !expression_has_effect(step)) {
5863                         warningf(step->base.source_position, "step of 'for'-statement has no effect");
5864                 }
5865         }
5866         expect(')');
5867         statement->fors.body = parse_loop_body(statement);
5868
5869         assert(scope == &statement->fors.scope);
5870         set_scope(last_scope);
5871         environment_pop_to(top);
5872
5873         return statement;
5874 }
5875
5876 /**
5877  * Parse a goto statement.
5878  */
5879 static statement_t *parse_goto(void)
5880 {
5881         eat(T_goto);
5882
5883         if(token.type != T_IDENTIFIER) {
5884                 parse_error_expected("while parsing goto", T_IDENTIFIER, 0);
5885                 eat_statement();
5886                 return NULL;
5887         }
5888         symbol_t *symbol = token.v.symbol;
5889         next_token();
5890
5891         declaration_t *label = get_label(symbol);
5892
5893         statement_t *statement          = allocate_statement_zero(STATEMENT_GOTO);
5894         statement->base.source_position = token.source_position;
5895
5896         statement->gotos.label = label;
5897
5898         /* remember the goto's in a list for later checking */
5899         if (goto_last == NULL) {
5900                 goto_first = &statement->gotos;
5901         } else {
5902                 goto_last->next = &statement->gotos;
5903         }
5904         goto_last = &statement->gotos;
5905
5906         expect(';');
5907
5908         return statement;
5909 }
5910
5911 /**
5912  * Parse a continue statement.
5913  */
5914 static statement_t *parse_continue(void)
5915 {
5916         statement_t *statement;
5917         if (current_loop == NULL) {
5918                 errorf(HERE, "continue statement not within loop");
5919                 statement = NULL;
5920         } else {
5921                 statement = allocate_statement_zero(STATEMENT_CONTINUE);
5922
5923                 statement->base.source_position = token.source_position;
5924         }
5925
5926         eat(T_continue);
5927         expect(';');
5928
5929         return statement;
5930 }
5931
5932 /**
5933  * Parse a break statement.
5934  */
5935 static statement_t *parse_break(void)
5936 {
5937         statement_t *statement;
5938         if (current_switch == NULL && current_loop == NULL) {
5939                 errorf(HERE, "break statement not within loop or switch");
5940                 statement = NULL;
5941         } else {
5942                 statement = allocate_statement_zero(STATEMENT_BREAK);
5943
5944                 statement->base.source_position = token.source_position;
5945         }
5946
5947         eat(T_break);
5948         expect(';');
5949
5950         return statement;
5951 }
5952
5953 /**
5954  * Check if a given declaration represents a local variable.
5955  */
5956 static bool is_local_var_declaration(const declaration_t *declaration) {
5957         switch ((storage_class_tag_t) declaration->storage_class) {
5958         case STORAGE_CLASS_AUTO:
5959         case STORAGE_CLASS_REGISTER: {
5960                 const type_t *type = skip_typeref(declaration->type);
5961                 if(is_type_function(type)) {
5962                         return false;
5963                 } else {
5964                         return true;
5965                 }
5966         }
5967         default:
5968                 return false;
5969         }
5970 }
5971
5972 /**
5973  * Check if a given declaration represents a variable.
5974  */
5975 static bool is_var_declaration(const declaration_t *declaration) {
5976         if(declaration->storage_class == STORAGE_CLASS_TYPEDEF)
5977                 return false;
5978
5979         const type_t *type = skip_typeref(declaration->type);
5980         return !is_type_function(type);
5981 }
5982
5983 /**
5984  * Check if a given expression represents a local variable.
5985  */
5986 static bool is_local_variable(const expression_t *expression)
5987 {
5988         if (expression->base.kind != EXPR_REFERENCE) {
5989                 return false;
5990         }
5991         const declaration_t *declaration = expression->reference.declaration;
5992         return is_local_var_declaration(declaration);
5993 }
5994
5995 /**
5996  * Check if a given expression represents a local variable and
5997  * return its declaration then, else return NULL.
5998  */
5999 declaration_t *expr_is_variable(const expression_t *expression)
6000 {
6001         if (expression->base.kind != EXPR_REFERENCE) {
6002                 return NULL;
6003         }
6004         declaration_t *declaration = expression->reference.declaration;
6005         if (is_var_declaration(declaration))
6006                 return declaration;
6007         return NULL;
6008 }
6009
6010 /**
6011  * Parse a return statement.
6012  */
6013 static statement_t *parse_return(void)
6014 {
6015         eat(T_return);
6016
6017         statement_t *statement          = allocate_statement_zero(STATEMENT_RETURN);
6018         statement->base.source_position = token.source_position;
6019
6020         expression_t *return_value = NULL;
6021         if(token.type != ';') {
6022                 return_value = parse_expression();
6023         }
6024         expect(';');
6025
6026         const type_t *const func_type = current_function->type;
6027         assert(is_type_function(func_type));
6028         type_t *const return_type = skip_typeref(func_type->function.return_type);
6029
6030         if(return_value != NULL) {
6031                 type_t *return_value_type = skip_typeref(return_value->base.type);
6032
6033                 if(is_type_atomic(return_type, ATOMIC_TYPE_VOID)
6034                                 && !is_type_atomic(return_value_type, ATOMIC_TYPE_VOID)) {
6035                         warningf(statement->base.source_position,
6036                                  "'return' with a value, in function returning void");
6037                         return_value = NULL;
6038                 } else {
6039                         type_t *const res_type = semantic_assign(return_type,
6040                                 return_value, "'return'");
6041                         if (res_type == NULL) {
6042                                 errorf(statement->base.source_position,
6043                                        "cannot return something of type '%T' in function returning '%T'",
6044                                        return_value->base.type, return_type);
6045                         } else {
6046                                 return_value = create_implicit_cast(return_value, res_type);
6047                         }
6048                 }
6049                 /* check for returning address of a local var */
6050                 if (return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
6051                         const expression_t *expression = return_value->unary.value;
6052                         if (is_local_variable(expression)) {
6053                                 warningf(statement->base.source_position,
6054                                          "function returns address of local variable");
6055                         }
6056                 }
6057         } else {
6058                 if(!is_type_atomic(return_type, ATOMIC_TYPE_VOID)) {
6059                         warningf(statement->base.source_position,
6060                                  "'return' without value, in function returning non-void");
6061                 }
6062         }
6063         statement->returns.value = return_value;
6064
6065         return statement;
6066 }
6067
6068 /**
6069  * Parse a declaration statement.
6070  */
6071 static statement_t *parse_declaration_statement(void)
6072 {
6073         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
6074
6075         statement->base.source_position = token.source_position;
6076
6077         declaration_t *before = last_declaration;
6078         parse_declaration(record_declaration);
6079
6080         if(before == NULL) {
6081                 statement->declaration.declarations_begin = scope->declarations;
6082         } else {
6083                 statement->declaration.declarations_begin = before->next;
6084         }
6085         statement->declaration.declarations_end = last_declaration;
6086
6087         return statement;
6088 }
6089
6090 /**
6091  * Parse an expression statement, ie. expr ';'.
6092  */
6093 static statement_t *parse_expression_statement(void)
6094 {
6095         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
6096
6097         statement->base.source_position  = token.source_position;
6098         expression_t *const expr         = parse_expression();
6099         statement->expression.expression = expr;
6100
6101         if (warning.unused_value  && !expression_has_effect(expr)) {
6102                 warningf(expr->base.source_position, "statement has no effect");
6103         }
6104
6105         expect(';');
6106
6107         return statement;
6108 }
6109
6110 /**
6111  * Parse a statement.
6112  */
6113 static statement_t *parse_statement(void)
6114 {
6115         statement_t   *statement = NULL;
6116
6117         /* declaration or statement */
6118         switch(token.type) {
6119         case T_asm:
6120                 statement = parse_asm_statement();
6121                 break;
6122
6123         case T_case:
6124                 statement = parse_case_statement();
6125                 break;
6126
6127         case T_default:
6128                 statement = parse_default_statement();
6129                 break;
6130
6131         case '{':
6132                 statement = parse_compound_statement();
6133                 break;
6134
6135         case T_if:
6136                 statement = parse_if();
6137                 break;
6138
6139         case T_switch:
6140                 statement = parse_switch();
6141                 break;
6142
6143         case T_while:
6144                 statement = parse_while();
6145                 break;
6146
6147         case T_do:
6148                 statement = parse_do();
6149                 break;
6150
6151         case T_for:
6152                 statement = parse_for();
6153                 break;
6154
6155         case T_goto:
6156                 statement = parse_goto();
6157                 break;
6158
6159         case T_continue:
6160                 statement = parse_continue();
6161                 break;
6162
6163         case T_break:
6164                 statement = parse_break();
6165                 break;
6166
6167         case T_return:
6168                 statement = parse_return();
6169                 break;
6170
6171         case ';':
6172                 if (warning.empty_statement) {
6173                         warningf(HERE, "statement is empty");
6174                 }
6175                 next_token();
6176                 statement = NULL;
6177                 break;
6178
6179         case T_IDENTIFIER:
6180                 if(look_ahead(1)->type == ':') {
6181                         statement = parse_label_statement();
6182                         break;
6183                 }
6184
6185                 if(is_typedef_symbol(token.v.symbol)) {
6186                         statement = parse_declaration_statement();
6187                         break;
6188                 }
6189
6190                 statement = parse_expression_statement();
6191                 break;
6192
6193         case T___extension__:
6194                 /* this can be a prefix to a declaration or an expression statement */
6195                 /* we simply eat it now and parse the rest with tail recursion */
6196                 do {
6197                         next_token();
6198                 } while(token.type == T___extension__);
6199                 statement = parse_statement();
6200                 break;
6201
6202         DECLARATION_START
6203                 statement = parse_declaration_statement();
6204                 break;
6205
6206         default:
6207                 statement = parse_expression_statement();
6208                 break;
6209         }
6210
6211         assert(statement == NULL
6212                         || statement->base.source_position.input_name != NULL);
6213
6214         return statement;
6215 }
6216
6217 /**
6218  * Parse a compound statement.
6219  */
6220 static statement_t *parse_compound_statement(void)
6221 {
6222         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
6223
6224         statement->base.source_position = token.source_position;
6225
6226         eat('{');
6227
6228         int      top        = environment_top();
6229         scope_t *last_scope = scope;
6230         set_scope(&statement->compound.scope);
6231
6232         statement_t *last_statement = NULL;
6233
6234         while(token.type != '}' && token.type != T_EOF) {
6235                 statement_t *sub_statement = parse_statement();
6236                 if(sub_statement == NULL)
6237                         continue;
6238
6239                 if(last_statement != NULL) {
6240                         last_statement->base.next = sub_statement;
6241                 } else {
6242                         statement->compound.statements = sub_statement;
6243                 }
6244
6245                 while(sub_statement->base.next != NULL)
6246                         sub_statement = sub_statement->base.next;
6247
6248                 last_statement = sub_statement;
6249         }
6250
6251         if(token.type == '}') {
6252                 next_token();
6253         } else {
6254                 errorf(statement->base.source_position,
6255                        "end of file while looking for closing '}'");
6256         }
6257
6258         assert(scope == &statement->compound.scope);
6259         set_scope(last_scope);
6260         environment_pop_to(top);
6261
6262         return statement;
6263 }
6264
6265 /**
6266  * Initialize builtin types.
6267  */
6268 static void initialize_builtin_types(void)
6269 {
6270         type_intmax_t    = make_global_typedef("__intmax_t__",      type_long_long);
6271         type_size_t      = make_global_typedef("__SIZE_TYPE__",     type_unsigned_long);
6272         type_ssize_t     = make_global_typedef("__SSIZE_TYPE__",    type_long);
6273         type_ptrdiff_t   = make_global_typedef("__PTRDIFF_TYPE__",  type_long);
6274         type_uintmax_t   = make_global_typedef("__uintmax_t__",     type_unsigned_long_long);
6275         type_uptrdiff_t  = make_global_typedef("__UPTRDIFF_TYPE__", type_unsigned_long);
6276         type_wchar_t     = make_global_typedef("__WCHAR_TYPE__",    type_int);
6277         type_wint_t      = make_global_typedef("__WINT_TYPE__",     type_int);
6278
6279         type_intmax_t_ptr  = make_pointer_type(type_intmax_t,  TYPE_QUALIFIER_NONE);
6280         type_ptrdiff_t_ptr = make_pointer_type(type_ptrdiff_t, TYPE_QUALIFIER_NONE);
6281         type_ssize_t_ptr   = make_pointer_type(type_ssize_t,   TYPE_QUALIFIER_NONE);
6282         type_wchar_t_ptr   = make_pointer_type(type_wchar_t,   TYPE_QUALIFIER_NONE);
6283 }
6284
6285 /**
6286  * Check for unused global static functions and variables
6287  */
6288 static void check_unused_globals(void)
6289 {
6290         if (!warning.unused_function && !warning.unused_variable)
6291                 return;
6292
6293         for (const declaration_t *decl = global_scope->declarations; decl != NULL; decl = decl->next) {
6294                 if (decl->used || decl->storage_class != STORAGE_CLASS_STATIC)
6295                         continue;
6296
6297                 type_t *const type = decl->type;
6298                 const char *s;
6299                 if (is_type_function(skip_typeref(type))) {
6300                         if (!warning.unused_function || decl->is_inline)
6301                                 continue;
6302
6303                         s = (decl->init.statement != NULL ? "defined" : "declared");
6304                 } else {
6305                         if (!warning.unused_variable)
6306                                 continue;
6307
6308                         s = "defined";
6309                 }
6310
6311                 warningf(decl->source_position, "'%#T' %s but not used",
6312                         type, decl->symbol, s);
6313         }
6314 }
6315
6316 /**
6317  * Parse a translation unit.
6318  */
6319 static translation_unit_t *parse_translation_unit(void)
6320 {
6321         translation_unit_t *unit = allocate_ast_zero(sizeof(unit[0]));
6322
6323         assert(global_scope == NULL);
6324         global_scope = &unit->scope;
6325
6326         assert(scope == NULL);
6327         set_scope(&unit->scope);
6328
6329         initialize_builtin_types();
6330
6331         while(token.type != T_EOF) {
6332                 if (token.type == ';') {
6333                         /* TODO error in strict mode */
6334                         warningf(HERE, "stray ';' outside of function");
6335                         next_token();
6336                 } else {
6337                         parse_external_declaration();
6338                 }
6339         }
6340
6341         assert(scope == &unit->scope);
6342         scope          = NULL;
6343         last_declaration = NULL;
6344
6345         assert(global_scope == &unit->scope);
6346         check_unused_globals();
6347         global_scope = NULL;
6348
6349         return unit;
6350 }
6351
6352 /**
6353  * Parse the input.
6354  *
6355  * @return  the translation unit or NULL if errors occurred.
6356  */
6357 translation_unit_t *parse(void)
6358 {
6359         environment_stack = NEW_ARR_F(stack_entry_t, 0);
6360         label_stack       = NEW_ARR_F(stack_entry_t, 0);
6361         diagnostic_count  = 0;
6362         error_count       = 0;
6363         warning_count     = 0;
6364
6365         type_set_output(stderr);
6366         ast_set_output(stderr);
6367
6368         lookahead_bufpos = 0;
6369         for(int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
6370                 next_token();
6371         }
6372         translation_unit_t *unit = parse_translation_unit();
6373
6374         DEL_ARR_F(environment_stack);
6375         DEL_ARR_F(label_stack);
6376
6377         if(error_count > 0)
6378                 return NULL;
6379
6380         return unit;
6381 }
6382
6383 /**
6384  * Initialize the parser.
6385  */
6386 void init_parser(void)
6387 {
6388         init_expression_parsers();
6389         obstack_init(&temp_obst);
6390
6391         symbol_t *const va_list_sym = symbol_table_insert("__builtin_va_list");
6392         type_valist = create_builtin_type(va_list_sym, type_void_ptr);
6393 }
6394
6395 /**
6396  * Terminate the parser.
6397  */
6398 void exit_parser(void)
6399 {
6400         obstack_free(&temp_obst, NULL);
6401 }