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