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                 if (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                 }
2354         } else if (warning.missing_declarations &&
2355             context == global_context &&
2356             !is_type_function(type) && (
2357               declaration->storage_class == STORAGE_CLASS_NONE ||
2358               declaration->storage_class == STORAGE_CLASS_THREAD
2359             )) {
2360                 warningf(declaration->source_position, "no previous declaration for '%#T'", type, symbol);
2361         }
2362
2363         assert(declaration->parent_context == NULL);
2364         assert(declaration->symbol != NULL);
2365         assert(context != NULL);
2366
2367         declaration->parent_context = context;
2368
2369         environment_push(declaration);
2370         return append_declaration(declaration);
2371 }
2372
2373 static declaration_t *record_declaration(declaration_t *declaration)
2374 {
2375         return internal_record_declaration(declaration, false);
2376 }
2377
2378 static declaration_t *record_function_definition(declaration_t *declaration)
2379 {
2380         return internal_record_declaration(declaration, true);
2381 }
2382
2383 static void parser_error_multiple_definition(declaration_t *declaration,
2384                 const source_position_t source_position)
2385 {
2386         errorf(source_position, "multiple definition of symbol '%Y'",
2387                declaration->symbol);
2388         errorf(declaration->source_position,
2389                "this is the location of the previous definition.");
2390 }
2391
2392 static bool is_declaration_specifier(const token_t *token,
2393                                      bool only_type_specifiers)
2394 {
2395         switch(token->type) {
2396                 TYPE_SPECIFIERS
2397                         return true;
2398                 case T_IDENTIFIER:
2399                         return is_typedef_symbol(token->v.symbol);
2400
2401                 case T___extension__:
2402                 STORAGE_CLASSES
2403                 TYPE_QUALIFIERS
2404                         return !only_type_specifiers;
2405
2406                 default:
2407                         return false;
2408         }
2409 }
2410
2411 static void parse_init_declarator_rest(declaration_t *declaration)
2412 {
2413         eat('=');
2414
2415         type_t *orig_type = declaration->type;
2416         type_t *type      = type = skip_typeref(orig_type);
2417
2418         if(declaration->init.initializer != NULL) {
2419                 parser_error_multiple_definition(declaration, token.source_position);
2420         }
2421
2422         initializer_t *initializer = parse_initializer(type);
2423
2424         /* § 6.7.5 (22)  array initializers for arrays with unknown size determine
2425          * the array type size */
2426         if(is_type_array(type) && initializer != NULL) {
2427                 array_type_t *array_type = &type->array;
2428
2429                 if(array_type->size == NULL) {
2430                         expression_t *cnst = allocate_expression_zero(EXPR_CONST);
2431
2432                         cnst->base.datatype = type_size_t;
2433
2434                         switch (initializer->kind) {
2435                                 case INITIALIZER_LIST: {
2436                                         cnst->conste.v.int_value = initializer->list.len;
2437                                         break;
2438                                 }
2439
2440                                 case INITIALIZER_STRING: {
2441                                         cnst->conste.v.int_value = initializer->string.string.size;
2442                                         break;
2443                                 }
2444
2445                                 case INITIALIZER_WIDE_STRING: {
2446                                         cnst->conste.v.int_value = initializer->wide_string.string.size;
2447                                         break;
2448                                 }
2449
2450                                 default:
2451                                         panic("invalid initializer type");
2452                         }
2453
2454                         array_type->size = cnst;
2455                 }
2456         }
2457
2458         if(is_type_function(type)) {
2459                 errorf(declaration->source_position,
2460                        "initializers not allowed for function types at declator '%Y' (type '%T')",
2461                        declaration->symbol, orig_type);
2462         } else {
2463                 declaration->init.initializer = initializer;
2464         }
2465 }
2466
2467 /* parse rest of a declaration without any declarator */
2468 static void parse_anonymous_declaration_rest(
2469                 const declaration_specifiers_t *specifiers,
2470                 parsed_declaration_func finished_declaration)
2471 {
2472         eat(';');
2473
2474         declaration_t *const declaration = allocate_declaration_zero();
2475         declaration->type            = specifiers->type;
2476         declaration->storage_class   = specifiers->storage_class;
2477         declaration->source_position = specifiers->source_position;
2478
2479         if (declaration->storage_class != STORAGE_CLASS_NONE) {
2480                 warningf(declaration->source_position, "useless storage class in empty declaration");
2481         }
2482
2483         type_t *type = declaration->type;
2484         switch (type->kind) {
2485                 case TYPE_COMPOUND_STRUCT:
2486                 case TYPE_COMPOUND_UNION: {
2487                         if (type->compound.declaration->symbol == NULL) {
2488                                 warningf(declaration->source_position, "unnamed struct/union that defines no instances");
2489                         }
2490                         break;
2491                 }
2492
2493                 case TYPE_ENUM:
2494                         break;
2495
2496                 default:
2497                         warningf(declaration->source_position, "empty declaration");
2498                         break;
2499         }
2500
2501         finished_declaration(declaration);
2502 }
2503
2504 static void parse_declaration_rest(declaration_t *ndeclaration,
2505                 const declaration_specifiers_t *specifiers,
2506                 parsed_declaration_func finished_declaration)
2507 {
2508         while(true) {
2509                 declaration_t *declaration = finished_declaration(ndeclaration);
2510
2511                 type_t *orig_type = declaration->type;
2512                 type_t *type      = skip_typeref(orig_type);
2513
2514                 if (type->kind != TYPE_FUNCTION &&
2515                     declaration->is_inline &&
2516                     is_type_valid(type)) {
2517                         warningf(declaration->source_position,
2518                                  "variable '%Y' declared 'inline'\n", declaration->symbol);
2519                 }
2520
2521                 if(token.type == '=') {
2522                         parse_init_declarator_rest(declaration);
2523                 }
2524
2525                 if(token.type != ',')
2526                         break;
2527                 eat(',');
2528
2529                 ndeclaration = parse_declarator(specifiers, /*may_be_abstract=*/false);
2530         }
2531         expect_void(';');
2532 }
2533
2534 static declaration_t *finished_kr_declaration(declaration_t *declaration)
2535 {
2536         symbol_t *symbol  = declaration->symbol;
2537         if(symbol == NULL) {
2538                 errorf(HERE, "anonymous declaration not valid as function parameter");
2539                 return declaration;
2540         }
2541         namespace_t namespc = (namespace_t) declaration->namespc;
2542         if(namespc != NAMESPACE_NORMAL) {
2543                 return record_declaration(declaration);
2544         }
2545
2546         declaration_t *previous_declaration = get_declaration(symbol, namespc);
2547         if(previous_declaration == NULL ||
2548                         previous_declaration->parent_context != context) {
2549                 errorf(HERE, "expected declaration of a function parameter, found '%Y'",
2550                        symbol);
2551                 return declaration;
2552         }
2553
2554         if(previous_declaration->type == NULL) {
2555                 previous_declaration->type           = declaration->type;
2556                 previous_declaration->storage_class  = declaration->storage_class;
2557                 previous_declaration->parent_context = context;
2558                 return previous_declaration;
2559         } else {
2560                 return record_declaration(declaration);
2561         }
2562 }
2563
2564 static void parse_declaration(parsed_declaration_func finished_declaration)
2565 {
2566         declaration_specifiers_t specifiers;
2567         memset(&specifiers, 0, sizeof(specifiers));
2568         parse_declaration_specifiers(&specifiers);
2569
2570         if(token.type == ';') {
2571                 parse_anonymous_declaration_rest(&specifiers, finished_declaration);
2572         } else {
2573                 declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
2574                 parse_declaration_rest(declaration, &specifiers, finished_declaration);
2575         }
2576 }
2577
2578 static void parse_kr_declaration_list(declaration_t *declaration)
2579 {
2580         type_t *type = skip_typeref(declaration->type);
2581         if(!is_type_function(type))
2582                 return;
2583
2584         if(!type->function.kr_style_parameters)
2585                 return;
2586
2587         /* push function parameters */
2588         int         top          = environment_top();
2589         context_t  *last_context = context;
2590         set_context(&declaration->context);
2591
2592         declaration_t *parameter = declaration->context.declarations;
2593         for( ; parameter != NULL; parameter = parameter->next) {
2594                 assert(parameter->parent_context == NULL);
2595                 parameter->parent_context = context;
2596                 environment_push(parameter);
2597         }
2598
2599         /* parse declaration list */
2600         while(is_declaration_specifier(&token, false)) {
2601                 parse_declaration(finished_kr_declaration);
2602         }
2603
2604         /* pop function parameters */
2605         assert(context == &declaration->context);
2606         set_context(last_context);
2607         environment_pop_to(top);
2608
2609         /* update function type */
2610         type_t *new_type = duplicate_type(type);
2611         new_type->function.kr_style_parameters = false;
2612
2613         function_parameter_t *parameters     = NULL;
2614         function_parameter_t *last_parameter = NULL;
2615
2616         declaration_t *parameter_declaration = declaration->context.declarations;
2617         for( ; parameter_declaration != NULL;
2618                         parameter_declaration = parameter_declaration->next) {
2619                 type_t *parameter_type = parameter_declaration->type;
2620                 if(parameter_type == NULL) {
2621                         if (strict_mode) {
2622                                 errorf(HERE, "no type specified for function parameter '%Y'",
2623                                        parameter_declaration->symbol);
2624                         } else {
2625                                 if (warning.implicit_int) {
2626                                         warningf(HERE, "no type specified for function parameter '%Y', using 'int'",
2627                                                 parameter_declaration->symbol);
2628                                 }
2629                                 parameter_type              = type_int;
2630                                 parameter_declaration->type = parameter_type;
2631                         }
2632                 }
2633
2634                 semantic_parameter(parameter_declaration);
2635                 parameter_type = parameter_declaration->type;
2636
2637                 function_parameter_t *function_parameter
2638                         = obstack_alloc(type_obst, sizeof(function_parameter[0]));
2639                 memset(function_parameter, 0, sizeof(function_parameter[0]));
2640
2641                 function_parameter->type = parameter_type;
2642                 if(last_parameter != NULL) {
2643                         last_parameter->next = function_parameter;
2644                 } else {
2645                         parameters = function_parameter;
2646                 }
2647                 last_parameter = function_parameter;
2648         }
2649         new_type->function.parameters = parameters;
2650
2651         type = typehash_insert(new_type);
2652         if(type != new_type) {
2653                 obstack_free(type_obst, new_type);
2654         }
2655
2656         declaration->type = type;
2657 }
2658
2659 /**
2660  * Check if all labels are defined in the current function.
2661  */
2662 static void check_for_missing_labels(void)
2663 {
2664         bool first_err = true;
2665         for (const goto_statement_t *goto_statement = goto_first;
2666              goto_statement != NULL;
2667              goto_statement = goto_statement->next) {
2668                  const declaration_t *label = goto_statement->label;
2669
2670                  if (label->source_position.input_name == NULL) {
2671                          if (first_err) {
2672                                  first_err = false;
2673                                  diagnosticf("%s: In function '%Y':\n",
2674                                          current_function->source_position.input_name,
2675                                          current_function->symbol);
2676                          }
2677                          errorf(goto_statement->statement.source_position,
2678                                  "label '%Y' used but not defined", label->symbol);
2679                  }
2680         }
2681         goto_first = goto_last = NULL;
2682 }
2683
2684 static void parse_external_declaration(void)
2685 {
2686         /* function-definitions and declarations both start with declaration
2687          * specifiers */
2688         declaration_specifiers_t specifiers;
2689         memset(&specifiers, 0, sizeof(specifiers));
2690         parse_declaration_specifiers(&specifiers);
2691
2692         /* must be a declaration */
2693         if(token.type == ';') {
2694                 parse_anonymous_declaration_rest(&specifiers, append_declaration);
2695                 return;
2696         }
2697
2698         /* declarator is common to both function-definitions and declarations */
2699         declaration_t *ndeclaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
2700
2701         /* must be a declaration */
2702         if(token.type == ',' || token.type == '=' || token.type == ';') {
2703                 parse_declaration_rest(ndeclaration, &specifiers, record_declaration);
2704                 return;
2705         }
2706
2707         /* must be a function definition */
2708         parse_kr_declaration_list(ndeclaration);
2709
2710         if(token.type != '{') {
2711                 parse_error_expected("while parsing function definition", '{', 0);
2712                 eat_statement();
2713                 return;
2714         }
2715
2716         type_t *type = ndeclaration->type;
2717
2718         /* note that we don't skip typerefs: the standard doesn't allow them here
2719          * (so we can't use is_type_function here) */
2720         if(type->kind != TYPE_FUNCTION) {
2721                 if (is_type_valid(type)) {
2722                         errorf(HERE, "declarator '%#T' has a body but is not a function type",
2723                                type, ndeclaration->symbol);
2724                 }
2725                 eat_block();
2726                 return;
2727         }
2728
2729         /* § 6.7.5.3 (14) a function definition with () means no
2730          * parameters (and not unspecified parameters) */
2731         if(type->function.unspecified_parameters) {
2732                 type_t *duplicate = duplicate_type(type);
2733                 duplicate->function.unspecified_parameters = false;
2734
2735                 type = typehash_insert(duplicate);
2736                 if(type != duplicate) {
2737                         obstack_free(type_obst, duplicate);
2738                 }
2739                 ndeclaration->type = type;
2740         }
2741
2742         declaration_t *const declaration = record_function_definition(ndeclaration);
2743         if(ndeclaration != declaration) {
2744                 declaration->context = ndeclaration->context;
2745         }
2746         type = skip_typeref(declaration->type);
2747
2748         /* push function parameters and switch context */
2749         int         top          = environment_top();
2750         context_t  *last_context = context;
2751         set_context(&declaration->context);
2752
2753         declaration_t *parameter = declaration->context.declarations;
2754         for( ; parameter != NULL; parameter = parameter->next) {
2755                 if(parameter->parent_context == &ndeclaration->context) {
2756                         parameter->parent_context = context;
2757                 }
2758                 assert(parameter->parent_context == NULL
2759                                 || parameter->parent_context == context);
2760                 parameter->parent_context = context;
2761                 environment_push(parameter);
2762         }
2763
2764         if(declaration->init.statement != NULL) {
2765                 parser_error_multiple_definition(declaration, token.source_position);
2766                 eat_block();
2767                 goto end_of_parse_external_declaration;
2768         } else {
2769                 /* parse function body */
2770                 int            label_stack_top      = label_top();
2771                 declaration_t *old_current_function = current_function;
2772                 current_function                    = declaration;
2773
2774                 declaration->init.statement = parse_compound_statement();
2775                 check_for_missing_labels();
2776
2777                 assert(current_function == declaration);
2778                 current_function = old_current_function;
2779                 label_pop_to(label_stack_top);
2780         }
2781
2782 end_of_parse_external_declaration:
2783         assert(context == &declaration->context);
2784         set_context(last_context);
2785         environment_pop_to(top);
2786 }
2787
2788 static type_t *make_bitfield_type(type_t *base, expression_t *size)
2789 {
2790         type_t *type        = allocate_type_zero(TYPE_BITFIELD);
2791         type->bitfield.base = base;
2792         type->bitfield.size = size;
2793
2794         return type;
2795 }
2796
2797 static void parse_struct_declarators(const declaration_specifiers_t *specifiers)
2798 {
2799         /* TODO: check constraints for struct declarations (in specifiers) */
2800         while(1) {
2801                 declaration_t *declaration;
2802
2803                 if(token.type == ':') {
2804                         next_token();
2805
2806                         type_t *base_type = specifiers->type;
2807                         expression_t *size = parse_constant_expression();
2808
2809                         type_t *type = make_bitfield_type(base_type, size);
2810
2811                         declaration = allocate_declaration_zero();
2812                         declaration->namespc         = NAMESPACE_NORMAL;
2813                         declaration->storage_class   = STORAGE_CLASS_NONE;
2814                         declaration->source_position = token.source_position;
2815                         declaration->modifiers       = specifiers->decl_modifiers;
2816                         declaration->type            = type;
2817                 } else {
2818                         declaration = parse_declarator(specifiers,/*may_be_abstract=*/true);
2819
2820                         if(token.type == ':') {
2821                                 next_token();
2822                                 expression_t *size = parse_constant_expression();
2823
2824                                 type_t *type = make_bitfield_type(declaration->type, size);
2825                                 declaration->type = type;
2826                         }
2827                 }
2828                 record_declaration(declaration);
2829
2830                 if(token.type != ',')
2831                         break;
2832                 next_token();
2833         }
2834         expect_void(';');
2835 }
2836
2837 static void parse_compound_type_entries(void)
2838 {
2839         eat('{');
2840
2841         while(token.type != '}' && token.type != T_EOF) {
2842                 declaration_specifiers_t specifiers;
2843                 memset(&specifiers, 0, sizeof(specifiers));
2844                 parse_declaration_specifiers(&specifiers);
2845
2846                 parse_struct_declarators(&specifiers);
2847         }
2848         if(token.type == T_EOF) {
2849                 errorf(HERE, "EOF while parsing struct");
2850         }
2851         next_token();
2852 }
2853
2854 static type_t *parse_typename(void)
2855 {
2856         declaration_specifiers_t specifiers;
2857         memset(&specifiers, 0, sizeof(specifiers));
2858         parse_declaration_specifiers(&specifiers);
2859         if(specifiers.storage_class != STORAGE_CLASS_NONE) {
2860                 /* TODO: improve error message, user does probably not know what a
2861                  * storage class is...
2862                  */
2863                 errorf(HERE, "typename may not have a storage class");
2864         }
2865
2866         type_t *result = parse_abstract_declarator(specifiers.type);
2867
2868         return result;
2869 }
2870
2871
2872
2873
2874 typedef expression_t* (*parse_expression_function) (unsigned precedence);
2875 typedef expression_t* (*parse_expression_infix_function) (unsigned precedence,
2876                                                           expression_t *left);
2877
2878 typedef struct expression_parser_function_t expression_parser_function_t;
2879 struct expression_parser_function_t {
2880         unsigned                         precedence;
2881         parse_expression_function        parser;
2882         unsigned                         infix_precedence;
2883         parse_expression_infix_function  infix_parser;
2884 };
2885
2886 expression_parser_function_t expression_parsers[T_LAST_TOKEN];
2887
2888 /**
2889  * Creates a new invalid expression.
2890  */
2891 static expression_t *create_invalid_expression(void)
2892 {
2893         expression_t *expression         = allocate_expression_zero(EXPR_INVALID);
2894         expression->base.source_position = token.source_position;
2895         return expression;
2896 }
2897
2898 /**
2899  * Prints an error message if an expression was expected but not read
2900  */
2901 static expression_t *expected_expression_error(void)
2902 {
2903         /* skip the error message if the error token was read */
2904         if (token.type != T_ERROR) {
2905                 errorf(HERE, "expected expression, got token '%K'", &token);
2906         }
2907         next_token();
2908
2909         return create_invalid_expression();
2910 }
2911
2912 /**
2913  * Parse a string constant.
2914  */
2915 static expression_t *parse_string_const(void)
2916 {
2917         expression_t *cnst  = allocate_expression_zero(EXPR_STRING_LITERAL);
2918         cnst->base.datatype = type_string;
2919         cnst->string.value  = parse_string_literals();
2920
2921         return cnst;
2922 }
2923
2924 /**
2925  * Parse a wide string constant.
2926  */
2927 static expression_t *parse_wide_string_const(void)
2928 {
2929         expression_t *const cnst = allocate_expression_zero(EXPR_WIDE_STRING_LITERAL);
2930         cnst->base.datatype      = type_wchar_t_ptr;
2931         cnst->wide_string.value  = token.v.wide_string; /* TODO concatenate */
2932         next_token();
2933         return cnst;
2934 }
2935
2936 /**
2937  * Parse an integer constant.
2938  */
2939 static expression_t *parse_int_const(void)
2940 {
2941         expression_t *cnst       = allocate_expression_zero(EXPR_CONST);
2942         cnst->base.datatype      = token.datatype;
2943         cnst->conste.v.int_value = token.v.intvalue;
2944
2945         next_token();
2946
2947         return cnst;
2948 }
2949
2950 /**
2951  * Parse a float constant.
2952  */
2953 static expression_t *parse_float_const(void)
2954 {
2955         expression_t *cnst         = allocate_expression_zero(EXPR_CONST);
2956         cnst->base.datatype        = token.datatype;
2957         cnst->conste.v.float_value = token.v.floatvalue;
2958
2959         next_token();
2960
2961         return cnst;
2962 }
2963
2964 static declaration_t *create_implicit_function(symbol_t *symbol,
2965                 const source_position_t source_position)
2966 {
2967         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
2968         ntype->function.return_type            = type_int;
2969         ntype->function.unspecified_parameters = true;
2970
2971         type_t *type = typehash_insert(ntype);
2972         if(type != ntype) {
2973                 free_type(ntype);
2974         }
2975
2976         declaration_t *const declaration = allocate_declaration_zero();
2977         declaration->storage_class   = STORAGE_CLASS_EXTERN;
2978         declaration->type            = type;
2979         declaration->symbol          = symbol;
2980         declaration->source_position = source_position;
2981         declaration->parent_context  = global_context;
2982
2983         context_t *old_context = context;
2984         set_context(global_context);
2985
2986         environment_push(declaration);
2987         /* prepend the declaration to the global declarations list */
2988         declaration->next     = context->declarations;
2989         context->declarations = declaration;
2990
2991         assert(context == global_context);
2992         set_context(old_context);
2993
2994         return declaration;
2995 }
2996
2997 /**
2998  * Creates a return_type (func)(argument_type) function type if not
2999  * already exists.
3000  *
3001  * @param return_type    the return type
3002  * @param argument_type  the argument type
3003  */
3004 static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
3005 {
3006         function_parameter_t *parameter
3007                 = obstack_alloc(type_obst, sizeof(parameter[0]));
3008         memset(parameter, 0, sizeof(parameter[0]));
3009         parameter->type = argument_type;
3010
3011         type_t *type               = allocate_type_zero(TYPE_FUNCTION);
3012         type->function.return_type = return_type;
3013         type->function.parameters  = parameter;
3014
3015         type_t *result = typehash_insert(type);
3016         if(result != type) {
3017                 free_type(type);
3018         }
3019
3020         return result;
3021 }
3022
3023 /**
3024  * Creates a function type for some function like builtins.
3025  *
3026  * @param symbol   the symbol describing the builtin
3027  */
3028 static type_t *get_builtin_symbol_type(symbol_t *symbol)
3029 {
3030         switch(symbol->ID) {
3031         case T___builtin_alloca:
3032                 return make_function_1_type(type_void_ptr, type_size_t);
3033         case T___builtin_nan:
3034                 return make_function_1_type(type_double, type_string);
3035         case T___builtin_nanf:
3036                 return make_function_1_type(type_float, type_string);
3037         case T___builtin_nand:
3038                 return make_function_1_type(type_long_double, type_string);
3039         case T___builtin_va_end:
3040                 return make_function_1_type(type_void, type_valist);
3041         default:
3042                 panic("not implemented builtin symbol found");
3043         }
3044 }
3045
3046 /**
3047  * Performs automatic type cast as described in § 6.3.2.1.
3048  *
3049  * @param orig_type  the original type
3050  */
3051 static type_t *automatic_type_conversion(type_t *orig_type)
3052 {
3053         type_t *type = skip_typeref(orig_type);
3054         if(is_type_array(type)) {
3055                 array_type_t *array_type   = &type->array;
3056                 type_t       *element_type = array_type->element_type;
3057                 unsigned      qualifiers   = array_type->type.qualifiers;
3058
3059                 return make_pointer_type(element_type, qualifiers);
3060         }
3061
3062         if(is_type_function(type)) {
3063                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
3064         }
3065
3066         return orig_type;
3067 }
3068
3069 /**
3070  * reverts the automatic casts of array to pointer types and function
3071  * to function-pointer types as defined § 6.3.2.1
3072  */
3073 type_t *revert_automatic_type_conversion(const expression_t *expression)
3074 {
3075         switch (expression->kind) {
3076                 case EXPR_REFERENCE: return expression->reference.declaration->type;
3077                 case EXPR_SELECT:    return expression->select.compound_entry->type;
3078
3079                 case EXPR_UNARY_DEREFERENCE: {
3080                         const expression_t *const value = expression->unary.value;
3081                         type_t             *const type  = skip_typeref(value->base.datatype);
3082                         assert(is_type_pointer(type));
3083                         return type->pointer.points_to;
3084                 }
3085
3086                 case EXPR_BUILTIN_SYMBOL:
3087                         return get_builtin_symbol_type(expression->builtin_symbol.symbol);
3088
3089                 case EXPR_ARRAY_ACCESS: {
3090                         const expression_t *const array_ref = expression->array_access.array_ref;
3091                         type_t             *const type_left = skip_typeref(array_ref->base.datatype);
3092                         if (!is_type_valid(type_left))
3093                                 return type_left;
3094                         assert(is_type_pointer(type_left));
3095                         return type_left->pointer.points_to;
3096                 }
3097
3098                 default: break;
3099         }
3100
3101         return expression->base.datatype;
3102 }
3103
3104 static expression_t *parse_reference(void)
3105 {
3106         expression_t *expression = allocate_expression_zero(EXPR_REFERENCE);
3107
3108         reference_expression_t *ref = &expression->reference;
3109         ref->symbol = token.v.symbol;
3110
3111         declaration_t *declaration = get_declaration(ref->symbol, NAMESPACE_NORMAL);
3112
3113         source_position_t source_position = token.source_position;
3114         next_token();
3115
3116         if(declaration == NULL) {
3117                 if (! strict_mode && token.type == '(') {
3118                         /* an implicitly defined function */
3119                         if (warning.implicit_function_declaration) {
3120                                 warningf(HERE, "implicit declaration of function '%Y'",
3121                                         ref->symbol);
3122                         }
3123
3124                         declaration = create_implicit_function(ref->symbol,
3125                                                                source_position);
3126                 } else {
3127                         errorf(HERE, "unknown symbol '%Y' found.", ref->symbol);
3128                         return expression;
3129                 }
3130         }
3131
3132         type_t *type         = declaration->type;
3133
3134         /* we always do the auto-type conversions; the & and sizeof parser contains
3135          * code to revert this! */
3136         type = automatic_type_conversion(type);
3137
3138         ref->declaration         = declaration;
3139         ref->expression.datatype = type;
3140
3141         return expression;
3142 }
3143
3144 static void check_cast_allowed(expression_t *expression, type_t *dest_type)
3145 {
3146         (void) expression;
3147         (void) dest_type;
3148         /* TODO check if explicit cast is allowed and issue warnings/errors */
3149 }
3150
3151 static expression_t *parse_cast(void)
3152 {
3153         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
3154
3155         cast->base.source_position = token.source_position;
3156
3157         type_t *type  = parse_typename();
3158
3159         expect(')');
3160         expression_t *value = parse_sub_expression(20);
3161
3162         check_cast_allowed(value, type);
3163
3164         cast->base.datatype = type;
3165         cast->unary.value   = value;
3166
3167         return cast;
3168 }
3169
3170 static expression_t *parse_statement_expression(void)
3171 {
3172         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
3173
3174         statement_t *statement           = parse_compound_statement();
3175         expression->statement.statement  = statement;
3176         expression->base.source_position = statement->base.source_position;
3177
3178         /* find last statement and use its type */
3179         type_t *type = type_void;
3180         const statement_t *stmt = statement->compound.statements;
3181         if (stmt != NULL) {
3182                 while (stmt->base.next != NULL)
3183                         stmt = stmt->base.next;
3184
3185                 if (stmt->kind == STATEMENT_EXPRESSION) {
3186                         type = stmt->expression.expression->base.datatype;
3187                 }
3188         } else {
3189                 warningf(expression->base.source_position, "empty statement expression ({})");
3190         }
3191         expression->base.datatype = type;
3192
3193         expect(')');
3194
3195         return expression;
3196 }
3197
3198 static expression_t *parse_brace_expression(void)
3199 {
3200         eat('(');
3201
3202         switch(token.type) {
3203         case '{':
3204                 /* gcc extension: a statement expression */
3205                 return parse_statement_expression();
3206
3207         TYPE_QUALIFIERS
3208         TYPE_SPECIFIERS
3209                 return parse_cast();
3210         case T_IDENTIFIER:
3211                 if(is_typedef_symbol(token.v.symbol)) {
3212                         return parse_cast();
3213                 }
3214         }
3215
3216         expression_t *result = parse_expression();
3217         expect(')');
3218
3219         return result;
3220 }
3221
3222 static expression_t *parse_function_keyword(void)
3223 {
3224         next_token();
3225         /* TODO */
3226
3227         if (current_function == NULL) {
3228                 errorf(HERE, "'__func__' used outside of a function");
3229         }
3230
3231         string_literal_expression_t *expression
3232                 = allocate_ast_zero(sizeof(expression[0]));
3233
3234         expression->expression.kind     = EXPR_FUNCTION;
3235         expression->expression.datatype = type_string;
3236
3237         return (expression_t*) expression;
3238 }
3239
3240 static expression_t *parse_pretty_function_keyword(void)
3241 {
3242         eat(T___PRETTY_FUNCTION__);
3243         /* TODO */
3244
3245         if (current_function == NULL) {
3246                 errorf(HERE, "'__PRETTY_FUNCTION__' used outside of a function");
3247         }
3248
3249         string_literal_expression_t *expression
3250                 = allocate_ast_zero(sizeof(expression[0]));
3251
3252         expression->expression.kind     = EXPR_PRETTY_FUNCTION;
3253         expression->expression.datatype = type_string;
3254
3255         return (expression_t*) expression;
3256 }
3257
3258 static designator_t *parse_designator(void)
3259 {
3260         designator_t *result = allocate_ast_zero(sizeof(result[0]));
3261
3262         if(token.type != T_IDENTIFIER) {
3263                 parse_error_expected("while parsing member designator",
3264                                      T_IDENTIFIER, 0);
3265                 eat_paren();
3266                 return NULL;
3267         }
3268         result->symbol = token.v.symbol;
3269         next_token();
3270
3271         designator_t *last_designator = result;
3272         while(true) {
3273                 if(token.type == '.') {
3274                         next_token();
3275                         if(token.type != T_IDENTIFIER) {
3276                                 parse_error_expected("while parsing member designator",
3277                                                      T_IDENTIFIER, 0);
3278                                 eat_paren();
3279                                 return NULL;
3280                         }
3281                         designator_t *designator = allocate_ast_zero(sizeof(result[0]));
3282                         designator->symbol       = token.v.symbol;
3283                         next_token();
3284
3285                         last_designator->next = designator;
3286                         last_designator       = designator;
3287                         continue;
3288                 }
3289                 if(token.type == '[') {
3290                         next_token();
3291                         designator_t *designator = allocate_ast_zero(sizeof(result[0]));
3292                         designator->array_access = parse_expression();
3293                         if(designator->array_access == NULL) {
3294                                 eat_paren();
3295                                 return NULL;
3296                         }
3297                         expect(']');
3298
3299                         last_designator->next = designator;
3300                         last_designator       = designator;
3301                         continue;
3302                 }
3303                 break;
3304         }
3305
3306         return result;
3307 }
3308
3309 static expression_t *parse_offsetof(void)
3310 {
3311         eat(T___builtin_offsetof);
3312
3313         expression_t *expression  = allocate_expression_zero(EXPR_OFFSETOF);
3314         expression->base.datatype = type_size_t;
3315
3316         expect('(');
3317         expression->offsetofe.type = parse_typename();
3318         expect(',');
3319         expression->offsetofe.designator = parse_designator();
3320         expect(')');
3321
3322         return expression;
3323 }
3324
3325 static expression_t *parse_va_start(void)
3326 {
3327         eat(T___builtin_va_start);
3328
3329         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
3330
3331         expect('(');
3332         expression->va_starte.ap = parse_assignment_expression();
3333         expect(',');
3334         expression_t *const expr = parse_assignment_expression();
3335         if (expr->kind == EXPR_REFERENCE) {
3336                 declaration_t *const decl = expr->reference.declaration;
3337                 if (decl->parent_context == &current_function->context &&
3338                     decl->next == NULL) {
3339                         expression->va_starte.parameter = decl;
3340                         expect(')');
3341                         return expression;
3342                 }
3343         }
3344         errorf(expr->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
3345
3346         return create_invalid_expression();
3347 }
3348
3349 static expression_t *parse_va_arg(void)
3350 {
3351         eat(T___builtin_va_arg);
3352
3353         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
3354
3355         expect('(');
3356         expression->va_arge.ap = parse_assignment_expression();
3357         expect(',');
3358         expression->base.datatype = parse_typename();
3359         expect(')');
3360
3361         return expression;
3362 }
3363
3364 static expression_t *parse_builtin_symbol(void)
3365 {
3366         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_SYMBOL);
3367
3368         symbol_t *symbol = token.v.symbol;
3369
3370         expression->builtin_symbol.symbol = symbol;
3371         next_token();
3372
3373         type_t *type = get_builtin_symbol_type(symbol);
3374         type = automatic_type_conversion(type);
3375
3376         expression->base.datatype = type;
3377         return expression;
3378 }
3379
3380 static expression_t *parse_builtin_constant(void)
3381 {
3382         eat(T___builtin_constant_p);
3383
3384         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
3385
3386         expect('(');
3387         expression->builtin_constant.value = parse_assignment_expression();
3388         expect(')');
3389         expression->base.datatype = type_int;
3390
3391         return expression;
3392 }
3393
3394 static expression_t *parse_builtin_prefetch(void)
3395 {
3396         eat(T___builtin_prefetch);
3397
3398         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_PREFETCH);
3399
3400         expect('(');
3401         expression->builtin_prefetch.adr = parse_assignment_expression();
3402         if (token.type == ',') {
3403                 next_token();
3404                 expression->builtin_prefetch.rw = parse_assignment_expression();
3405         }
3406         if (token.type == ',') {
3407                 next_token();
3408                 expression->builtin_prefetch.locality = parse_assignment_expression();
3409         }
3410         expect(')');
3411         expression->base.datatype = type_void;
3412
3413         return expression;
3414 }
3415
3416 static expression_t *parse_compare_builtin(void)
3417 {
3418         expression_t *expression;
3419
3420         switch(token.type) {
3421         case T___builtin_isgreater:
3422                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATER);
3423                 break;
3424         case T___builtin_isgreaterequal:
3425                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATEREQUAL);
3426                 break;
3427         case T___builtin_isless:
3428                 expression = allocate_expression_zero(EXPR_BINARY_ISLESS);
3429                 break;
3430         case T___builtin_islessequal:
3431                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSEQUAL);
3432                 break;
3433         case T___builtin_islessgreater:
3434                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSGREATER);
3435                 break;
3436         case T___builtin_isunordered:
3437                 expression = allocate_expression_zero(EXPR_BINARY_ISUNORDERED);
3438                 break;
3439         default:
3440                 panic("invalid compare builtin found");
3441                 break;
3442         }
3443         next_token();
3444
3445         expect('(');
3446         expression->binary.left = parse_assignment_expression();
3447         expect(',');
3448         expression->binary.right = parse_assignment_expression();
3449         expect(')');
3450
3451         type_t *const orig_type_left  = expression->binary.left->base.datatype;
3452         type_t *const orig_type_right = expression->binary.right->base.datatype;
3453
3454         type_t *const type_left  = skip_typeref(orig_type_left);
3455         type_t *const type_right = skip_typeref(orig_type_right);
3456         if(!is_type_floating(type_left) && !is_type_floating(type_right)) {
3457                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
3458                         type_error_incompatible("invalid operands in comparison",
3459                                 token.source_position, orig_type_left, orig_type_right);
3460                 }
3461         } else {
3462                 semantic_comparison(&expression->binary);
3463         }
3464
3465         return expression;
3466 }
3467
3468 static expression_t *parse_builtin_expect(void)
3469 {
3470         eat(T___builtin_expect);
3471
3472         expression_t *expression
3473                 = allocate_expression_zero(EXPR_BINARY_BUILTIN_EXPECT);
3474
3475         expect('(');
3476         expression->binary.left = parse_assignment_expression();
3477         expect(',');
3478         expression->binary.right = parse_constant_expression();
3479         expect(')');
3480
3481         expression->base.datatype = expression->binary.left->base.datatype;
3482
3483         return expression;
3484 }
3485
3486 static expression_t *parse_assume(void) {
3487         eat(T_assume);
3488
3489         expression_t *expression
3490                 = allocate_expression_zero(EXPR_UNARY_ASSUME);
3491
3492         expect('(');
3493         expression->unary.value = parse_assignment_expression();
3494         expect(')');
3495
3496         expression->base.datatype = type_void;
3497         return expression;
3498 }
3499
3500 static expression_t *parse_alignof(void) {
3501         eat(T___alignof__);
3502
3503         expression_t *expression
3504                 = allocate_expression_zero(EXPR_ALIGNOF);
3505
3506         expect('(');
3507         expression->alignofe.type = parse_typename();
3508         expect(')');
3509
3510         expression->base.datatype = type_size_t;
3511         return expression;
3512 }
3513
3514 static expression_t *parse_primary_expression(void)
3515 {
3516         switch(token.type) {
3517         case T_INTEGER:
3518                 return parse_int_const();
3519         case T_FLOATINGPOINT:
3520                 return parse_float_const();
3521         case T_STRING_LITERAL:
3522                 return parse_string_const();
3523         case T_WIDE_STRING_LITERAL:
3524                 return parse_wide_string_const();
3525         case T_IDENTIFIER:
3526                 return parse_reference();
3527         case T___FUNCTION__:
3528         case T___func__:
3529                 return parse_function_keyword();
3530         case T___PRETTY_FUNCTION__:
3531                 return parse_pretty_function_keyword();
3532         case T___builtin_offsetof:
3533                 return parse_offsetof();
3534         case T___builtin_va_start:
3535                 return parse_va_start();
3536         case T___builtin_va_arg:
3537                 return parse_va_arg();
3538         case T___builtin_expect:
3539                 return parse_builtin_expect();
3540         case T___builtin_nanf:
3541         case T___builtin_alloca:
3542         case T___builtin_va_end:
3543                 return parse_builtin_symbol();
3544         case T___builtin_isgreater:
3545         case T___builtin_isgreaterequal:
3546         case T___builtin_isless:
3547         case T___builtin_islessequal:
3548         case T___builtin_islessgreater:
3549         case T___builtin_isunordered:
3550                 return parse_compare_builtin();
3551         case T___builtin_constant_p:
3552                 return parse_builtin_constant();
3553         case T___builtin_prefetch:
3554                 return parse_builtin_prefetch();
3555         case T___alignof__:
3556                 return parse_alignof();
3557         case T_assume:
3558                 return parse_assume();
3559
3560         case '(':
3561                 return parse_brace_expression();
3562         }
3563
3564         errorf(HERE, "unexpected token '%K'", &token);
3565         eat_statement();
3566
3567         return create_invalid_expression();
3568 }
3569
3570 /**
3571  * Check if the expression has the character type and issue a warning then.
3572  */
3573 static void check_for_char_index_type(const expression_t *expression) {
3574         type_t       *const type      = expression->base.datatype;
3575         const type_t *const base_type = skip_typeref(type);
3576
3577         if (is_type_atomic(base_type, ATOMIC_TYPE_CHAR) &&
3578                         warning.char_subscripts) {
3579                 warningf(expression->base.source_position,
3580                         "array subscript has type '%T'", type);
3581         }
3582 }
3583
3584 static expression_t *parse_array_expression(unsigned precedence,
3585                                             expression_t *left)
3586 {
3587         (void) precedence;
3588
3589         eat('[');
3590
3591         expression_t *inside = parse_expression();
3592
3593         array_access_expression_t *array_access
3594                 = allocate_ast_zero(sizeof(array_access[0]));
3595
3596         array_access->expression.kind = EXPR_ARRAY_ACCESS;
3597
3598         type_t *const orig_type_left   = left->base.datatype;
3599         type_t *const orig_type_inside = inside->base.datatype;
3600
3601         type_t *const type_left   = skip_typeref(orig_type_left);
3602         type_t *const type_inside = skip_typeref(orig_type_inside);
3603
3604         type_t *return_type;
3605         if (is_type_pointer(type_left)) {
3606                 return_type             = type_left->pointer.points_to;
3607                 array_access->array_ref = left;
3608                 array_access->index     = inside;
3609                 check_for_char_index_type(inside);
3610         } else if (is_type_pointer(type_inside)) {
3611                 return_type             = type_inside->pointer.points_to;
3612                 array_access->array_ref = inside;
3613                 array_access->index     = left;
3614                 array_access->flipped   = true;
3615                 check_for_char_index_type(left);
3616         } else {
3617                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
3618                         errorf(HERE,
3619                                 "array access on object with non-pointer types '%T', '%T'",
3620                                 orig_type_left, orig_type_inside);
3621                 }
3622                 return_type             = type_error_type;
3623                 array_access->array_ref = create_invalid_expression();
3624         }
3625
3626         if(token.type != ']') {
3627                 parse_error_expected("Problem while parsing array access", ']', 0);
3628                 return (expression_t*) array_access;
3629         }
3630         next_token();
3631
3632         return_type = automatic_type_conversion(return_type);
3633         array_access->expression.datatype = return_type;
3634
3635         return (expression_t*) array_access;
3636 }
3637
3638 static expression_t *parse_sizeof(unsigned precedence)
3639 {
3640         eat(T_sizeof);
3641
3642         sizeof_expression_t *sizeof_expression
3643                 = allocate_ast_zero(sizeof(sizeof_expression[0]));
3644         sizeof_expression->expression.kind     = EXPR_SIZEOF;
3645         sizeof_expression->expression.datatype = type_size_t;
3646
3647         if(token.type == '(' && is_declaration_specifier(look_ahead(1), true)) {
3648                 next_token();
3649                 sizeof_expression->type = parse_typename();
3650                 expect(')');
3651         } else {
3652                 expression_t *expression  = parse_sub_expression(precedence);
3653                 expression->base.datatype = revert_automatic_type_conversion(expression);
3654
3655                 sizeof_expression->type            = expression->base.datatype;
3656                 sizeof_expression->size_expression = expression;
3657         }
3658
3659         return (expression_t*) sizeof_expression;
3660 }
3661
3662 static expression_t *parse_select_expression(unsigned precedence,
3663                                              expression_t *compound)
3664 {
3665         (void) precedence;
3666         assert(token.type == '.' || token.type == T_MINUSGREATER);
3667
3668         bool is_pointer = (token.type == T_MINUSGREATER);
3669         next_token();
3670
3671         expression_t *select    = allocate_expression_zero(EXPR_SELECT);
3672         select->select.compound = compound;
3673
3674         if(token.type != T_IDENTIFIER) {
3675                 parse_error_expected("while parsing select", T_IDENTIFIER, 0);
3676                 return select;
3677         }
3678         symbol_t *symbol      = token.v.symbol;
3679         select->select.symbol = symbol;
3680         next_token();
3681
3682         type_t *const orig_type = compound->base.datatype;
3683         type_t *const type      = skip_typeref(orig_type);
3684
3685         type_t *type_left = type;
3686         if(is_pointer) {
3687                 if (!is_type_pointer(type)) {
3688                         if (is_type_valid(type)) {
3689                                 errorf(HERE, "left hand side of '->' is not a pointer, but '%T'", orig_type);
3690                         }
3691                         return create_invalid_expression();
3692                 }
3693                 type_left = type->pointer.points_to;
3694         }
3695         type_left = skip_typeref(type_left);
3696
3697         if (type_left->kind != TYPE_COMPOUND_STRUCT &&
3698             type_left->kind != TYPE_COMPOUND_UNION) {
3699                 if (is_type_valid(type_left)) {
3700                         errorf(HERE, "request for member '%Y' in something not a struct or "
3701                                "union, but '%T'", symbol, type_left);
3702                 }
3703                 return create_invalid_expression();
3704         }
3705
3706         declaration_t *const declaration = type_left->compound.declaration;
3707
3708         if(!declaration->init.is_defined) {
3709                 errorf(HERE, "request for member '%Y' of incomplete type '%T'",
3710                        symbol, type_left);
3711                 return create_invalid_expression();
3712         }
3713
3714         declaration_t *iter = declaration->context.declarations;
3715         for( ; iter != NULL; iter = iter->next) {
3716                 if(iter->symbol == symbol) {
3717                         break;
3718                 }
3719         }
3720         if(iter == NULL) {
3721                 errorf(HERE, "'%T' has no member named '%Y'", orig_type, symbol);
3722                 return create_invalid_expression();
3723         }
3724
3725         /* we always do the auto-type conversions; the & and sizeof parser contains
3726          * code to revert this! */
3727         type_t *expression_type = automatic_type_conversion(iter->type);
3728
3729         select->select.compound_entry = iter;
3730         select->base.datatype         = expression_type;
3731
3732         if(expression_type->kind == TYPE_BITFIELD) {
3733                 expression_t *extract
3734                         = allocate_expression_zero(EXPR_UNARY_BITFIELD_EXTRACT);
3735                 extract->unary.value   = select;
3736                 extract->base.datatype = expression_type->bitfield.base;
3737
3738                 return extract;
3739         }
3740
3741         return select;
3742 }
3743
3744 /**
3745  * Parse a call expression, ie. expression '( ... )'.
3746  *
3747  * @param expression  the function address
3748  */
3749 static expression_t *parse_call_expression(unsigned precedence,
3750                                            expression_t *expression)
3751 {
3752         (void) precedence;
3753         expression_t *result = allocate_expression_zero(EXPR_CALL);
3754
3755         call_expression_t *call = &result->call;
3756         call->function          = expression;
3757
3758         type_t *const orig_type = expression->base.datatype;
3759         type_t *const type      = skip_typeref(orig_type);
3760
3761         function_type_t *function_type = NULL;
3762         if (is_type_pointer(type)) {
3763                 type_t *const to_type = skip_typeref(type->pointer.points_to);
3764
3765                 if (is_type_function(to_type)) {
3766                         function_type             = &to_type->function;
3767                         call->expression.datatype = function_type->return_type;
3768                 }
3769         }
3770
3771         if (function_type == NULL && is_type_valid(type)) {
3772                 errorf(HERE, "called object '%E' (type '%T') is not a pointer to a function", expression, orig_type);
3773         }
3774
3775         /* parse arguments */
3776         eat('(');
3777
3778         if(token.type != ')') {
3779                 call_argument_t *last_argument = NULL;
3780
3781                 while(true) {
3782                         call_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
3783
3784                         argument->expression = parse_assignment_expression();
3785                         if(last_argument == NULL) {
3786                                 call->arguments = argument;
3787                         } else {
3788                                 last_argument->next = argument;
3789                         }
3790                         last_argument = argument;
3791
3792                         if(token.type != ',')
3793                                 break;
3794                         next_token();
3795                 }
3796         }
3797         expect(')');
3798
3799         if(function_type != NULL) {
3800                 function_parameter_t *parameter = function_type->parameters;
3801                 call_argument_t      *argument  = call->arguments;
3802                 for( ; parameter != NULL && argument != NULL;
3803                                 parameter = parameter->next, argument = argument->next) {
3804                         type_t *expected_type = parameter->type;
3805                         /* TODO report context in error messages */
3806                         expression_t *const arg_expr = argument->expression;
3807                         type_t       *const res_type = semantic_assign(expected_type, arg_expr, "function call");
3808                         if (res_type == NULL) {
3809                                 /* TODO improve error message */
3810                                 errorf(arg_expr->base.source_position,
3811                                         "Cannot call function with argument '%E' of type '%T' where type '%T' is expected",
3812                                         arg_expr, arg_expr->base.datatype, expected_type);
3813                         } else {
3814                                 argument->expression = create_implicit_cast(argument->expression, expected_type);
3815                         }
3816                 }
3817                 /* too few parameters */
3818                 if(parameter != NULL) {
3819                         errorf(HERE, "too few arguments to function '%E'", expression);
3820                 } else if(argument != NULL) {
3821                         /* too many parameters */
3822                         if(!function_type->variadic
3823                                         && !function_type->unspecified_parameters) {
3824                                 errorf(HERE, "too many arguments to function '%E'", expression);
3825                         } else {
3826                                 /* do default promotion */
3827                                 for( ; argument != NULL; argument = argument->next) {
3828                                         type_t *type = argument->expression->base.datatype;
3829
3830                                         type = skip_typeref(type);
3831                                         if(is_type_integer(type)) {
3832                                                 type = promote_integer(type);
3833                                         } else if(type == type_float) {
3834                                                 type = type_double;
3835                                         }
3836
3837                                         argument->expression
3838                                                 = create_implicit_cast(argument->expression, type);
3839                                 }
3840
3841                                 check_format(&result->call);
3842                         }
3843                 } else {
3844                         check_format(&result->call);
3845                 }
3846         }
3847
3848         return result;
3849 }
3850
3851 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
3852
3853 static bool same_compound_type(const type_t *type1, const type_t *type2)
3854 {
3855         return
3856                 is_type_compound(type1) &&
3857                 type1->kind == type2->kind &&
3858                 type1->compound.declaration == type2->compound.declaration;
3859 }
3860
3861 /**
3862  * Parse a conditional expression, ie. 'expression ? ... : ...'.
3863  *
3864  * @param expression  the conditional expression
3865  */
3866 static expression_t *parse_conditional_expression(unsigned precedence,
3867                                                   expression_t *expression)
3868 {
3869         eat('?');
3870
3871         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
3872
3873         conditional_expression_t *conditional = &result->conditional;
3874         conditional->condition = expression;
3875
3876         /* 6.5.15.2 */
3877         type_t *const condition_type_orig = expression->base.datatype;
3878         type_t *const condition_type      = skip_typeref(condition_type_orig);
3879         if (!is_type_scalar(condition_type) && is_type_valid(condition_type)) {
3880                 type_error("expected a scalar type in conditional condition",
3881                            expression->base.source_position, condition_type_orig);
3882         }
3883
3884         expression_t *true_expression = parse_expression();
3885         expect(':');
3886         expression_t *false_expression = parse_sub_expression(precedence);
3887
3888         conditional->true_expression  = true_expression;
3889         conditional->false_expression = false_expression;
3890
3891         type_t *const orig_true_type  = true_expression->base.datatype;
3892         type_t *const orig_false_type = false_expression->base.datatype;
3893         type_t *const true_type       = skip_typeref(orig_true_type);
3894         type_t *const false_type      = skip_typeref(orig_false_type);
3895
3896         /* 6.5.15.3 */
3897         type_t *result_type;
3898         if (is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
3899                 result_type = semantic_arithmetic(true_type, false_type);
3900
3901                 true_expression  = create_implicit_cast(true_expression, result_type);
3902                 false_expression = create_implicit_cast(false_expression, result_type);
3903
3904                 conditional->true_expression     = true_expression;
3905                 conditional->false_expression    = false_expression;
3906                 conditional->expression.datatype = result_type;
3907         } else if (same_compound_type(true_type, false_type) || (
3908             is_type_atomic(true_type, ATOMIC_TYPE_VOID) &&
3909             is_type_atomic(false_type, ATOMIC_TYPE_VOID)
3910                 )) {
3911                 /* just take 1 of the 2 types */
3912                 result_type = true_type;
3913         } else if (is_type_pointer(true_type) && is_type_pointer(false_type)
3914                         && pointers_compatible(true_type, false_type)) {
3915                 /* ok */
3916                 result_type = true_type;
3917         } else {
3918                 /* TODO */
3919                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
3920                         type_error_incompatible("while parsing conditional",
3921                                                 expression->base.source_position, true_type,
3922                                                 false_type);
3923                 }
3924                 result_type = type_error_type;
3925         }
3926
3927         conditional->expression.datatype = result_type;
3928         return result;
3929 }
3930
3931 /**
3932  * Parse an extension expression.
3933  */
3934 static expression_t *parse_extension(unsigned precedence)
3935 {
3936         eat(T___extension__);
3937
3938         /* TODO enable extensions */
3939         expression_t *expression = parse_sub_expression(precedence);
3940         /* TODO disable extensions */
3941         return expression;
3942 }
3943
3944 static expression_t *parse_builtin_classify_type(const unsigned precedence)
3945 {
3946         eat(T___builtin_classify_type);
3947
3948         expression_t *result  = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
3949         result->base.datatype = type_int;
3950
3951         expect('(');
3952         expression_t *expression = parse_sub_expression(precedence);
3953         expect(')');
3954         result->classify_type.type_expression = expression;
3955
3956         return result;
3957 }
3958
3959 static void semantic_incdec(unary_expression_t *expression)
3960 {
3961         type_t *const orig_type = expression->value->base.datatype;
3962         type_t *const type      = skip_typeref(orig_type);
3963         /* TODO !is_type_real && !is_type_pointer */
3964         if(!is_type_arithmetic(type) && type->kind != TYPE_POINTER) {
3965                 if (is_type_valid(type)) {
3966                         /* TODO: improve error message */
3967                         errorf(HERE, "operation needs an arithmetic or pointer type");
3968                 }
3969                 return;
3970         }
3971
3972         expression->expression.datatype = orig_type;
3973 }
3974
3975 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
3976 {
3977         type_t *const orig_type = expression->value->base.datatype;
3978         type_t *const type      = skip_typeref(orig_type);
3979         if(!is_type_arithmetic(type)) {
3980                 if (is_type_valid(type)) {
3981                         /* TODO: improve error message */
3982                         errorf(HERE, "operation needs an arithmetic type");
3983                 }
3984                 return;
3985         }
3986
3987         expression->expression.datatype = orig_type;
3988 }
3989
3990 static void semantic_unexpr_scalar(unary_expression_t *expression)
3991 {
3992         type_t *const orig_type = expression->value->base.datatype;
3993         type_t *const type      = skip_typeref(orig_type);
3994         if (!is_type_scalar(type)) {
3995                 if (is_type_valid(type)) {
3996                         errorf(HERE, "operand of ! must be of scalar type");
3997                 }
3998                 return;
3999         }
4000
4001         expression->expression.datatype = orig_type;
4002 }
4003
4004 static void semantic_unexpr_integer(unary_expression_t *expression)
4005 {
4006         type_t *const orig_type = expression->value->base.datatype;
4007         type_t *const type      = skip_typeref(orig_type);
4008         if (!is_type_integer(type)) {
4009                 if (is_type_valid(type)) {
4010                         errorf(HERE, "operand of ~ must be of integer type");
4011                 }
4012                 return;
4013         }
4014
4015         expression->expression.datatype = orig_type;
4016 }
4017
4018 static void semantic_dereference(unary_expression_t *expression)
4019 {
4020         type_t *const orig_type = expression->value->base.datatype;
4021         type_t *const type      = skip_typeref(orig_type);
4022         if(!is_type_pointer(type)) {
4023                 if (is_type_valid(type)) {
4024                         errorf(HERE, "Unary '*' needs pointer or arrray type, but type '%T' given", orig_type);
4025                 }
4026                 return;
4027         }
4028
4029         type_t *result_type = type->pointer.points_to;
4030         result_type = automatic_type_conversion(result_type);
4031         expression->expression.datatype = result_type;
4032 }
4033
4034 /**
4035  * Check the semantic of the address taken expression.
4036  */
4037 static void semantic_take_addr(unary_expression_t *expression)
4038 {
4039         expression_t *value  = expression->value;
4040         value->base.datatype = revert_automatic_type_conversion(value);
4041
4042         type_t *orig_type = value->base.datatype;
4043         if(!is_type_valid(orig_type))
4044                 return;
4045
4046         if(value->kind == EXPR_REFERENCE) {
4047                 declaration_t *const declaration = value->reference.declaration;
4048                 if(declaration != NULL) {
4049                         if (declaration->storage_class == STORAGE_CLASS_REGISTER) {
4050                                 errorf(expression->expression.source_position,
4051                                         "address of register variable '%Y' requested",
4052                                         declaration->symbol);
4053                         }
4054                         declaration->address_taken = 1;
4055                 }
4056         }
4057
4058         expression->expression.datatype = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
4059 }
4060
4061 #define CREATE_UNARY_EXPRESSION_PARSER(token_type, unexpression_type, sfunc)   \
4062 static expression_t *parse_##unexpression_type(unsigned precedence)            \
4063 {                                                                              \
4064         eat(token_type);                                                           \
4065                                                                                    \
4066         expression_t *unary_expression                                             \
4067                 = allocate_expression_zero(unexpression_type);                         \
4068         unary_expression->base.source_position = HERE;                             \
4069         unary_expression->unary.value = parse_sub_expression(precedence);          \
4070                                                                                    \
4071         sfunc(&unary_expression->unary);                                           \
4072                                                                                    \
4073         return unary_expression;                                                   \
4074 }
4075
4076 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
4077                                semantic_unexpr_arithmetic)
4078 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
4079                                semantic_unexpr_arithmetic)
4080 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
4081                                semantic_unexpr_scalar)
4082 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
4083                                semantic_dereference)
4084 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
4085                                semantic_take_addr)
4086 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
4087                                semantic_unexpr_integer)
4088 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
4089                                semantic_incdec)
4090 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
4091                                semantic_incdec)
4092
4093 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_type, unexpression_type, \
4094                                                sfunc)                         \
4095 static expression_t *parse_##unexpression_type(unsigned precedence,           \
4096                                                expression_t *left)            \
4097 {                                                                             \
4098         (void) precedence;                                                        \
4099         eat(token_type);                                                          \
4100                                                                               \
4101         expression_t *unary_expression                                            \
4102                 = allocate_expression_zero(unexpression_type);                        \
4103         unary_expression->unary.value = left;                                     \
4104                                                                                   \
4105         sfunc(&unary_expression->unary);                                          \
4106                                                                               \
4107         return unary_expression;                                                  \
4108 }
4109
4110 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
4111                                        EXPR_UNARY_POSTFIX_INCREMENT,
4112                                        semantic_incdec)
4113 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
4114                                        EXPR_UNARY_POSTFIX_DECREMENT,
4115                                        semantic_incdec)
4116
4117 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
4118 {
4119         /* TODO: handle complex + imaginary types */
4120
4121         /* § 6.3.1.8 Usual arithmetic conversions */
4122         if(type_left == type_long_double || type_right == type_long_double) {
4123                 return type_long_double;
4124         } else if(type_left == type_double || type_right == type_double) {
4125                 return type_double;
4126         } else if(type_left == type_float || type_right == type_float) {
4127                 return type_float;
4128         }
4129
4130         type_right = promote_integer(type_right);
4131         type_left  = promote_integer(type_left);
4132
4133         if(type_left == type_right)
4134                 return type_left;
4135
4136         bool signed_left  = is_type_signed(type_left);
4137         bool signed_right = is_type_signed(type_right);
4138         int  rank_left    = get_rank(type_left);
4139         int  rank_right   = get_rank(type_right);
4140         if(rank_left < rank_right) {
4141                 if(signed_left == signed_right || !signed_right) {
4142                         return type_right;
4143                 } else {
4144                         return type_left;
4145                 }
4146         } else {
4147                 if(signed_left == signed_right || !signed_left) {
4148                         return type_left;
4149                 } else {
4150                         return type_right;
4151                 }
4152         }
4153 }
4154
4155 /**
4156  * Check the semantic restrictions for a binary expression.
4157  */
4158 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
4159 {
4160         expression_t *const left            = expression->left;
4161         expression_t *const right           = expression->right;
4162         type_t       *const orig_type_left  = left->base.datatype;
4163         type_t       *const orig_type_right = right->base.datatype;
4164         type_t       *const type_left       = skip_typeref(orig_type_left);
4165         type_t       *const type_right      = skip_typeref(orig_type_right);
4166
4167         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4168                 /* TODO: improve error message */
4169                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4170                         errorf(HERE, "operation needs arithmetic types");
4171                 }
4172                 return;
4173         }
4174
4175         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4176         expression->left  = create_implicit_cast(left, arithmetic_type);
4177         expression->right = create_implicit_cast(right, arithmetic_type);
4178         expression->expression.datatype = arithmetic_type;
4179 }
4180
4181 static void semantic_shift_op(binary_expression_t *expression)
4182 {
4183         expression_t *const left            = expression->left;
4184         expression_t *const right           = expression->right;
4185         type_t       *const orig_type_left  = left->base.datatype;
4186         type_t       *const orig_type_right = right->base.datatype;
4187         type_t       *      type_left       = skip_typeref(orig_type_left);
4188         type_t       *      type_right      = skip_typeref(orig_type_right);
4189
4190         if(!is_type_integer(type_left) || !is_type_integer(type_right)) {
4191                 /* TODO: improve error message */
4192                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4193                         errorf(HERE, "operation needs integer types");
4194                 }
4195                 return;
4196         }
4197
4198         type_left  = promote_integer(type_left);
4199         type_right = promote_integer(type_right);
4200
4201         expression->left  = create_implicit_cast(left, type_left);
4202         expression->right = create_implicit_cast(right, type_right);
4203         expression->expression.datatype = type_left;
4204 }
4205
4206 static void semantic_add(binary_expression_t *expression)
4207 {
4208         expression_t *const left            = expression->left;
4209         expression_t *const right           = expression->right;
4210         type_t       *const orig_type_left  = left->base.datatype;
4211         type_t       *const orig_type_right = right->base.datatype;
4212         type_t       *const type_left       = skip_typeref(orig_type_left);
4213         type_t       *const type_right      = skip_typeref(orig_type_right);
4214
4215         /* § 5.6.5 */
4216         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4217                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4218                 expression->left  = create_implicit_cast(left, arithmetic_type);
4219                 expression->right = create_implicit_cast(right, arithmetic_type);
4220                 expression->expression.datatype = arithmetic_type;
4221                 return;
4222         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4223                 expression->expression.datatype = type_left;
4224         } else if(is_type_pointer(type_right) && is_type_integer(type_left)) {
4225                 expression->expression.datatype = type_right;
4226         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4227                 errorf(HERE, "invalid operands to binary + ('%T', '%T')", orig_type_left, orig_type_right);
4228         }
4229 }
4230
4231 static void semantic_sub(binary_expression_t *expression)
4232 {
4233         expression_t *const left            = expression->left;
4234         expression_t *const right           = expression->right;
4235         type_t       *const orig_type_left  = left->base.datatype;
4236         type_t       *const orig_type_right = right->base.datatype;
4237         type_t       *const type_left       = skip_typeref(orig_type_left);
4238         type_t       *const type_right      = skip_typeref(orig_type_right);
4239
4240         /* § 5.6.5 */
4241         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4242                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4243                 expression->left  = create_implicit_cast(left, arithmetic_type);
4244                 expression->right = create_implicit_cast(right, arithmetic_type);
4245                 expression->expression.datatype = arithmetic_type;
4246                 return;
4247         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4248                 expression->expression.datatype = type_left;
4249         } else if(is_type_pointer(type_left) && is_type_pointer(type_right)) {
4250                 if(!pointers_compatible(type_left, type_right)) {
4251                         errorf(HERE, "pointers to incompatible objects to binary '-' ('%T', '%T')", orig_type_left, orig_type_right);
4252                 } else {
4253                         expression->expression.datatype = type_ptrdiff_t;
4254                 }
4255         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4256                 errorf(HERE, "invalid operands to binary '-' ('%T', '%T')", orig_type_left, orig_type_right);
4257         }
4258 }
4259
4260 static void semantic_comparison(binary_expression_t *expression)
4261 {
4262         expression_t *left            = expression->left;
4263         expression_t *right           = expression->right;
4264         type_t       *orig_type_left  = left->base.datatype;
4265         type_t       *orig_type_right = right->base.datatype;
4266
4267         type_t *type_left  = skip_typeref(orig_type_left);
4268         type_t *type_right = skip_typeref(orig_type_right);
4269
4270         /* TODO non-arithmetic types */
4271         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4272                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4273                 expression->left  = create_implicit_cast(left, arithmetic_type);
4274                 expression->right = create_implicit_cast(right, arithmetic_type);
4275                 expression->expression.datatype = arithmetic_type;
4276         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
4277                 /* TODO check compatibility */
4278         } else if (is_type_pointer(type_left)) {
4279                 expression->right = create_implicit_cast(right, type_left);
4280         } else if (is_type_pointer(type_right)) {
4281                 expression->left = create_implicit_cast(left, type_right);
4282         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4283                 type_error_incompatible("invalid operands in comparison",
4284                                         token.source_position, type_left, type_right);
4285         }
4286         expression->expression.datatype = type_int;
4287 }
4288
4289 static void semantic_arithmetic_assign(binary_expression_t *expression)
4290 {
4291         expression_t *left            = expression->left;
4292         expression_t *right           = expression->right;
4293         type_t       *orig_type_left  = left->base.datatype;
4294         type_t       *orig_type_right = right->base.datatype;
4295
4296         type_t *type_left  = skip_typeref(orig_type_left);
4297         type_t *type_right = skip_typeref(orig_type_right);
4298
4299         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4300                 /* TODO: improve error message */
4301                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4302                         errorf(HERE, "operation needs arithmetic types");
4303                 }
4304                 return;
4305         }
4306
4307         /* combined instructions are tricky. We can't create an implicit cast on
4308          * the left side, because we need the uncasted form for the store.
4309          * The ast2firm pass has to know that left_type must be right_type
4310          * for the arithmetic operation and create a cast by itself */
4311         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4312         expression->right       = create_implicit_cast(right, arithmetic_type);
4313         expression->expression.datatype = type_left;
4314 }
4315
4316 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
4317 {
4318         expression_t *const left            = expression->left;
4319         expression_t *const right           = expression->right;
4320         type_t       *const orig_type_left  = left->base.datatype;
4321         type_t       *const orig_type_right = right->base.datatype;
4322         type_t       *const type_left       = skip_typeref(orig_type_left);
4323         type_t       *const type_right      = skip_typeref(orig_type_right);
4324
4325         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4326                 /* combined instructions are tricky. We can't create an implicit cast on
4327                  * the left side, because we need the uncasted form for the store.
4328                  * The ast2firm pass has to know that left_type must be right_type
4329                  * for the arithmetic operation and create a cast by itself */
4330                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
4331                 expression->right = create_implicit_cast(right, arithmetic_type);
4332                 expression->expression.datatype = type_left;
4333         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
4334                 expression->expression.datatype = type_left;
4335         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4336                 errorf(HERE, "incompatible types '%T' and '%T' in assignment", orig_type_left, orig_type_right);
4337         }
4338 }
4339
4340 /**
4341  * Check the semantic restrictions of a logical expression.
4342  */
4343 static void semantic_logical_op(binary_expression_t *expression)
4344 {
4345         expression_t *const left            = expression->left;
4346         expression_t *const right           = expression->right;
4347         type_t       *const orig_type_left  = left->base.datatype;
4348         type_t       *const orig_type_right = right->base.datatype;
4349         type_t       *const type_left       = skip_typeref(orig_type_left);
4350         type_t       *const type_right      = skip_typeref(orig_type_right);
4351
4352         if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
4353                 /* TODO: improve error message */
4354                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4355                         errorf(HERE, "operation needs scalar types");
4356                 }
4357                 return;
4358         }
4359
4360         expression->expression.datatype = type_int;
4361 }
4362
4363 /**
4364  * Checks if a compound type has constant fields.
4365  */
4366 static bool has_const_fields(const compound_type_t *type)
4367 {
4368         const context_t     *context = &type->declaration->context;
4369         const declaration_t *declaration = context->declarations;
4370
4371         for (; declaration != NULL; declaration = declaration->next) {
4372                 if (declaration->namespc != NAMESPACE_NORMAL)
4373                         continue;
4374
4375                 const type_t *decl_type = skip_typeref(declaration->type);
4376                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
4377                         return true;
4378         }
4379         /* TODO */
4380         return false;
4381 }
4382
4383 /**
4384  * Check the semantic restrictions of a binary assign expression.
4385  */
4386 static void semantic_binexpr_assign(binary_expression_t *expression)
4387 {
4388         expression_t *left           = expression->left;
4389         type_t       *orig_type_left = left->base.datatype;
4390
4391         type_t *type_left = revert_automatic_type_conversion(left);
4392         type_left         = skip_typeref(orig_type_left);
4393
4394         /* must be a modifiable lvalue */
4395         if (is_type_array(type_left)) {
4396                 errorf(HERE, "cannot assign to arrays ('%E')", left);
4397                 return;
4398         }
4399         if(type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
4400                 errorf(HERE, "assignment to readonly location '%E' (type '%T')", left,
4401                        orig_type_left);
4402                 return;
4403         }
4404         if(is_type_incomplete(type_left)) {
4405                 errorf(HERE,
4406                        "left-hand side of assignment '%E' has incomplete type '%T'",
4407                        left, orig_type_left);
4408                 return;
4409         }
4410         if(is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
4411                 errorf(HERE, "cannot assign to '%E' because compound type '%T' has readonly fields",
4412                        left, orig_type_left);
4413                 return;
4414         }
4415
4416         type_t *const res_type = semantic_assign(orig_type_left, expression->right,
4417                                                  "assignment");
4418         if (res_type == NULL) {
4419                 errorf(expression->expression.source_position,
4420                         "cannot assign to '%T' from '%T'",
4421                         orig_type_left, expression->right->base.datatype);
4422         } else {
4423                 expression->right = create_implicit_cast(expression->right, res_type);
4424         }
4425
4426         expression->expression.datatype = orig_type_left;
4427 }
4428
4429 static bool expression_has_effect(const expression_t *const expr)
4430 {
4431         switch (expr->kind) {
4432                 case EXPR_UNKNOWN:                   break;
4433                 case EXPR_INVALID:                   break;
4434                 case EXPR_REFERENCE:                 return false;
4435                 case EXPR_CONST:                     return false;
4436                 case EXPR_STRING_LITERAL:            return false;
4437                 case EXPR_WIDE_STRING_LITERAL:       return false;
4438                 case EXPR_CALL: {
4439                         const call_expression_t *const call = &expr->call;
4440                         if (call->function->kind != EXPR_BUILTIN_SYMBOL)
4441                                 return true;
4442
4443                         switch (call->function->builtin_symbol.symbol->ID) {
4444                                 case T___builtin_va_end: return true;
4445                                 default:                 return false;
4446                         }
4447                 }
4448                 case EXPR_CONDITIONAL: {
4449                         const conditional_expression_t *const cond = &expr->conditional;
4450                         return
4451                                 expression_has_effect(cond->true_expression) &&
4452                                 expression_has_effect(cond->false_expression);
4453                 }
4454                 case EXPR_SELECT:                    return false;
4455                 case EXPR_ARRAY_ACCESS:              return false;
4456                 case EXPR_SIZEOF:                    return false;
4457                 case EXPR_CLASSIFY_TYPE:             return false;
4458                 case EXPR_ALIGNOF:                   return false;
4459
4460                 case EXPR_FUNCTION:                  return false;
4461                 case EXPR_PRETTY_FUNCTION:           return false;
4462                 case EXPR_BUILTIN_SYMBOL:            break; /* handled in EXPR_CALL */
4463                 case EXPR_BUILTIN_CONSTANT_P:        return false;
4464                 case EXPR_BUILTIN_PREFETCH:          return true;
4465                 case EXPR_OFFSETOF:                  return false;
4466                 case EXPR_VA_START:                  return true;
4467                 case EXPR_VA_ARG:                    return true;
4468                 case EXPR_STATEMENT:                 return true; // TODO
4469
4470                 case EXPR_UNARY_NEGATE:              return false;
4471                 case EXPR_UNARY_PLUS:                return false;
4472                 case EXPR_UNARY_BITWISE_NEGATE:      return false;
4473                 case EXPR_UNARY_NOT:                 return false;
4474                 case EXPR_UNARY_DEREFERENCE:         return false;
4475                 case EXPR_UNARY_TAKE_ADDRESS:        return false;
4476                 case EXPR_UNARY_POSTFIX_INCREMENT:   return true;
4477                 case EXPR_UNARY_POSTFIX_DECREMENT:   return true;
4478                 case EXPR_UNARY_PREFIX_INCREMENT:    return true;
4479                 case EXPR_UNARY_PREFIX_DECREMENT:    return true;
4480                 case EXPR_UNARY_CAST:
4481                         return is_type_atomic(expr->base.datatype, ATOMIC_TYPE_VOID);
4482                 case EXPR_UNARY_CAST_IMPLICIT:       return true;
4483                 case EXPR_UNARY_ASSUME:              return true;
4484                 case EXPR_UNARY_BITFIELD_EXTRACT:    return false;
4485
4486                 case EXPR_BINARY_ADD:                return false;
4487                 case EXPR_BINARY_SUB:                return false;
4488                 case EXPR_BINARY_MUL:                return false;
4489                 case EXPR_BINARY_DIV:                return false;
4490                 case EXPR_BINARY_MOD:                return false;
4491                 case EXPR_BINARY_EQUAL:              return false;
4492                 case EXPR_BINARY_NOTEQUAL:           return false;
4493                 case EXPR_BINARY_LESS:               return false;
4494                 case EXPR_BINARY_LESSEQUAL:          return false;
4495                 case EXPR_BINARY_GREATER:            return false;
4496                 case EXPR_BINARY_GREATEREQUAL:       return false;
4497                 case EXPR_BINARY_BITWISE_AND:        return false;
4498                 case EXPR_BINARY_BITWISE_OR:         return false;
4499                 case EXPR_BINARY_BITWISE_XOR:        return false;
4500                 case EXPR_BINARY_SHIFTLEFT:          return false;
4501                 case EXPR_BINARY_SHIFTRIGHT:         return false;
4502                 case EXPR_BINARY_ASSIGN:             return true;
4503                 case EXPR_BINARY_MUL_ASSIGN:         return true;
4504                 case EXPR_BINARY_DIV_ASSIGN:         return true;
4505                 case EXPR_BINARY_MOD_ASSIGN:         return true;
4506                 case EXPR_BINARY_ADD_ASSIGN:         return true;
4507                 case EXPR_BINARY_SUB_ASSIGN:         return true;
4508                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:   return true;
4509                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:  return true;
4510                 case EXPR_BINARY_BITWISE_AND_ASSIGN: return true;
4511                 case EXPR_BINARY_BITWISE_XOR_ASSIGN: return true;
4512                 case EXPR_BINARY_BITWISE_OR_ASSIGN:  return true;
4513                 case EXPR_BINARY_LOGICAL_AND:
4514                 case EXPR_BINARY_LOGICAL_OR:
4515                 case EXPR_BINARY_COMMA:
4516                         return expression_has_effect(expr->binary.right);
4517
4518                 case EXPR_BINARY_BUILTIN_EXPECT:     return true;
4519                 case EXPR_BINARY_ISGREATER:          return false;
4520                 case EXPR_BINARY_ISGREATEREQUAL:     return false;
4521                 case EXPR_BINARY_ISLESS:             return false;
4522                 case EXPR_BINARY_ISLESSEQUAL:        return false;
4523                 case EXPR_BINARY_ISLESSGREATER:      return false;
4524                 case EXPR_BINARY_ISUNORDERED:        return false;
4525         }
4526
4527         panic("unexpected statement");
4528 }
4529
4530 static void semantic_comma(binary_expression_t *expression)
4531 {
4532         if (warning.unused_value) {
4533                 const expression_t *const left = expression->left;
4534                 if (!expression_has_effect(left)) {
4535                         warningf(left->base.source_position, "left-hand operand of comma expression has no effect");
4536                 }
4537         }
4538         expression->expression.datatype = expression->right->base.datatype;
4539 }
4540
4541 #define CREATE_BINEXPR_PARSER(token_type, binexpression_type, sfunc, lr)  \
4542 static expression_t *parse_##binexpression_type(unsigned precedence,      \
4543                                                 expression_t *left)       \
4544 {                                                                         \
4545         eat(token_type);                                                      \
4546                                                                           \
4547         expression_t *right = parse_sub_expression(precedence + lr);          \
4548                                                                           \
4549         expression_t *binexpr = allocate_expression_zero(binexpression_type); \
4550         binexpr->binary.left  = left;                                         \
4551         binexpr->binary.right = right;                                        \
4552         sfunc(&binexpr->binary);                                              \
4553                                                                           \
4554         return binexpr;                                                       \
4555 }
4556
4557 CREATE_BINEXPR_PARSER(',', EXPR_BINARY_COMMA,    semantic_comma, 1)
4558 CREATE_BINEXPR_PARSER('*', EXPR_BINARY_MUL,      semantic_binexpr_arithmetic, 1)
4559 CREATE_BINEXPR_PARSER('/', EXPR_BINARY_DIV,      semantic_binexpr_arithmetic, 1)
4560 CREATE_BINEXPR_PARSER('%', EXPR_BINARY_MOD,      semantic_binexpr_arithmetic, 1)
4561 CREATE_BINEXPR_PARSER('+', EXPR_BINARY_ADD,      semantic_add, 1)
4562 CREATE_BINEXPR_PARSER('-', EXPR_BINARY_SUB,      semantic_sub, 1)
4563 CREATE_BINEXPR_PARSER('<', EXPR_BINARY_LESS,     semantic_comparison, 1)
4564 CREATE_BINEXPR_PARSER('>', EXPR_BINARY_GREATER,  semantic_comparison, 1)
4565 CREATE_BINEXPR_PARSER('=', EXPR_BINARY_ASSIGN,   semantic_binexpr_assign, 0)
4566
4567 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,
4568                       semantic_comparison, 1)
4569 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,
4570                       semantic_comparison, 1)
4571 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,
4572                       semantic_comparison, 1)
4573 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,
4574                       semantic_comparison, 1)
4575
4576 CREATE_BINEXPR_PARSER('&', EXPR_BINARY_BITWISE_AND,
4577                       semantic_binexpr_arithmetic, 1)
4578 CREATE_BINEXPR_PARSER('|', EXPR_BINARY_BITWISE_OR,
4579                       semantic_binexpr_arithmetic, 1)
4580 CREATE_BINEXPR_PARSER('^', EXPR_BINARY_BITWISE_XOR,
4581                       semantic_binexpr_arithmetic, 1)
4582 CREATE_BINEXPR_PARSER(T_ANDAND, EXPR_BINARY_LOGICAL_AND,
4583                       semantic_logical_op, 1)
4584 CREATE_BINEXPR_PARSER(T_PIPEPIPE, EXPR_BINARY_LOGICAL_OR,
4585                       semantic_logical_op, 1)
4586 CREATE_BINEXPR_PARSER(T_LESSLESS, EXPR_BINARY_SHIFTLEFT,
4587                       semantic_shift_op, 1)
4588 CREATE_BINEXPR_PARSER(T_GREATERGREATER, EXPR_BINARY_SHIFTRIGHT,
4589                       semantic_shift_op, 1)
4590 CREATE_BINEXPR_PARSER(T_PLUSEQUAL, EXPR_BINARY_ADD_ASSIGN,
4591                       semantic_arithmetic_addsubb_assign, 0)
4592 CREATE_BINEXPR_PARSER(T_MINUSEQUAL, EXPR_BINARY_SUB_ASSIGN,
4593                       semantic_arithmetic_addsubb_assign, 0)
4594 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL, EXPR_BINARY_MUL_ASSIGN,
4595                       semantic_arithmetic_assign, 0)
4596 CREATE_BINEXPR_PARSER(T_SLASHEQUAL, EXPR_BINARY_DIV_ASSIGN,
4597                       semantic_arithmetic_assign, 0)
4598 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL, EXPR_BINARY_MOD_ASSIGN,
4599                       semantic_arithmetic_assign, 0)
4600 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL, EXPR_BINARY_SHIFTLEFT_ASSIGN,
4601                       semantic_arithmetic_assign, 0)
4602 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL, EXPR_BINARY_SHIFTRIGHT_ASSIGN,
4603                       semantic_arithmetic_assign, 0)
4604 CREATE_BINEXPR_PARSER(T_ANDEQUAL, EXPR_BINARY_BITWISE_AND_ASSIGN,
4605                       semantic_arithmetic_assign, 0)
4606 CREATE_BINEXPR_PARSER(T_PIPEEQUAL, EXPR_BINARY_BITWISE_OR_ASSIGN,
4607                       semantic_arithmetic_assign, 0)
4608 CREATE_BINEXPR_PARSER(T_CARETEQUAL, EXPR_BINARY_BITWISE_XOR_ASSIGN,
4609                       semantic_arithmetic_assign, 0)
4610
4611 static expression_t *parse_sub_expression(unsigned precedence)
4612 {
4613         if(token.type < 0) {
4614                 return expected_expression_error();
4615         }
4616
4617         expression_parser_function_t *parser
4618                 = &expression_parsers[token.type];
4619         source_position_t             source_position = token.source_position;
4620         expression_t                 *left;
4621
4622         if(parser->parser != NULL) {
4623                 left = parser->parser(parser->precedence);
4624         } else {
4625                 left = parse_primary_expression();
4626         }
4627         assert(left != NULL);
4628         left->base.source_position = source_position;
4629
4630         while(true) {
4631                 if(token.type < 0) {
4632                         return expected_expression_error();
4633                 }
4634
4635                 parser = &expression_parsers[token.type];
4636                 if(parser->infix_parser == NULL)
4637                         break;
4638                 if(parser->infix_precedence < precedence)
4639                         break;
4640
4641                 left = parser->infix_parser(parser->infix_precedence, left);
4642
4643                 assert(left != NULL);
4644                 assert(left->kind != EXPR_UNKNOWN);
4645                 left->base.source_position = source_position;
4646         }
4647
4648         return left;
4649 }
4650
4651 /**
4652  * Parse an expression.
4653  */
4654 static expression_t *parse_expression(void)
4655 {
4656         return parse_sub_expression(1);
4657 }
4658
4659 /**
4660  * Register a parser for a prefix-like operator with given precedence.
4661  *
4662  * @param parser      the parser function
4663  * @param token_type  the token type of the prefix token
4664  * @param precedence  the precedence of the operator
4665  */
4666 static void register_expression_parser(parse_expression_function parser,
4667                                        int token_type, unsigned precedence)
4668 {
4669         expression_parser_function_t *entry = &expression_parsers[token_type];
4670
4671         if(entry->parser != NULL) {
4672                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
4673                 panic("trying to register multiple expression parsers for a token");
4674         }
4675         entry->parser     = parser;
4676         entry->precedence = precedence;
4677 }
4678
4679 /**
4680  * Register a parser for an infix operator with given precedence.
4681  *
4682  * @param parser      the parser function
4683  * @param token_type  the token type of the infix operator
4684  * @param precedence  the precedence of the operator
4685  */
4686 static void register_infix_parser(parse_expression_infix_function parser,
4687                 int token_type, unsigned precedence)
4688 {
4689         expression_parser_function_t *entry = &expression_parsers[token_type];
4690
4691         if(entry->infix_parser != NULL) {
4692                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
4693                 panic("trying to register multiple infix expression parsers for a "
4694                       "token");
4695         }
4696         entry->infix_parser     = parser;
4697         entry->infix_precedence = precedence;
4698 }
4699
4700 /**
4701  * Initialize the expression parsers.
4702  */
4703 static void init_expression_parsers(void)
4704 {
4705         memset(&expression_parsers, 0, sizeof(expression_parsers));
4706
4707         register_infix_parser(parse_array_expression,         '[',              30);
4708         register_infix_parser(parse_call_expression,          '(',              30);
4709         register_infix_parser(parse_select_expression,        '.',              30);
4710         register_infix_parser(parse_select_expression,        T_MINUSGREATER,   30);
4711         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,
4712                                                               T_PLUSPLUS,       30);
4713         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,
4714                                                               T_MINUSMINUS,     30);
4715
4716         register_infix_parser(parse_EXPR_BINARY_MUL,          '*',              16);
4717         register_infix_parser(parse_EXPR_BINARY_DIV,          '/',              16);
4718         register_infix_parser(parse_EXPR_BINARY_MOD,          '%',              16);
4719         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,    T_LESSLESS,       16);
4720         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,   T_GREATERGREATER, 16);
4721         register_infix_parser(parse_EXPR_BINARY_ADD,          '+',              15);
4722         register_infix_parser(parse_EXPR_BINARY_SUB,          '-',              15);
4723         register_infix_parser(parse_EXPR_BINARY_LESS,         '<',              14);
4724         register_infix_parser(parse_EXPR_BINARY_GREATER,      '>',              14);
4725         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,    T_LESSEQUAL,      14);
4726         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL, T_GREATEREQUAL,   14);
4727         register_infix_parser(parse_EXPR_BINARY_EQUAL,        T_EQUALEQUAL,     13);
4728         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,
4729                                                     T_EXCLAMATIONMARKEQUAL, 13);
4730         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,  '&',              12);
4731         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,  '^',              11);
4732         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,   '|',              10);
4733         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,  T_ANDAND,          9);
4734         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,   T_PIPEPIPE,        8);
4735         register_infix_parser(parse_conditional_expression,   '?',               7);
4736         register_infix_parser(parse_EXPR_BINARY_ASSIGN,       '=',               2);
4737         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,   T_PLUSEQUAL,       2);
4738         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,   T_MINUSEQUAL,      2);
4739         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,   T_ASTERISKEQUAL,   2);
4740         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,   T_SLASHEQUAL,      2);
4741         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,   T_PERCENTEQUAL,    2);
4742         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,
4743                                                                 T_LESSLESSEQUAL, 2);
4744         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,
4745                                                           T_GREATERGREATEREQUAL, 2);
4746         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN,
4747                                                                      T_ANDEQUAL, 2);
4748         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,
4749                                                                     T_PIPEEQUAL, 2);
4750         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN,
4751                                                                    T_CARETEQUAL, 2);
4752
4753         register_infix_parser(parse_EXPR_BINARY_COMMA,        ',',               1);
4754
4755         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-',      25);
4756         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+',      25);
4757         register_expression_parser(parse_EXPR_UNARY_NOT,              '!',      25);
4758         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~',      25);
4759         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*',      25);
4760         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&',      25);
4761         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT,
4762                                                                   T_PLUSPLUS,   25);
4763         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT,
4764                                                                   T_MINUSMINUS, 25);
4765         register_expression_parser(parse_sizeof,                  T_sizeof,     25);
4766         register_expression_parser(parse_extension,            T___extension__, 25);
4767         register_expression_parser(parse_builtin_classify_type,
4768                                                      T___builtin_classify_type, 25);
4769 }
4770
4771 /**
4772  * Parse a asm statement constraints specification.
4773  */
4774 static asm_constraint_t *parse_asm_constraints(void)
4775 {
4776         asm_constraint_t *result = NULL;
4777         asm_constraint_t *last   = NULL;
4778
4779         while(token.type == T_STRING_LITERAL || token.type == '[') {
4780                 asm_constraint_t *constraint = allocate_ast_zero(sizeof(constraint[0]));
4781                 memset(constraint, 0, sizeof(constraint[0]));
4782
4783                 if(token.type == '[') {
4784                         eat('[');
4785                         if(token.type != T_IDENTIFIER) {
4786                                 parse_error_expected("while parsing asm constraint",
4787                                                      T_IDENTIFIER, 0);
4788                                 return NULL;
4789                         }
4790                         constraint->symbol = token.v.symbol;
4791
4792                         expect(']');
4793                 }
4794
4795                 constraint->constraints = parse_string_literals();
4796                 expect('(');
4797                 constraint->expression = parse_expression();
4798                 expect(')');
4799
4800                 if(last != NULL) {
4801                         last->next = constraint;
4802                 } else {
4803                         result = constraint;
4804                 }
4805                 last = constraint;
4806
4807                 if(token.type != ',')
4808                         break;
4809                 eat(',');
4810         }
4811
4812         return result;
4813 }
4814
4815 /**
4816  * Parse a asm statement clobber specification.
4817  */
4818 static asm_clobber_t *parse_asm_clobbers(void)
4819 {
4820         asm_clobber_t *result = NULL;
4821         asm_clobber_t *last   = NULL;
4822
4823         while(token.type == T_STRING_LITERAL) {
4824                 asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
4825                 clobber->clobber       = parse_string_literals();
4826
4827                 if(last != NULL) {
4828                         last->next = clobber;
4829                 } else {
4830                         result = clobber;
4831                 }
4832                 last = clobber;
4833
4834                 if(token.type != ',')
4835                         break;
4836                 eat(',');
4837         }
4838
4839         return result;
4840 }
4841
4842 /**
4843  * Parse an asm statement.
4844  */
4845 static statement_t *parse_asm_statement(void)
4846 {
4847         eat(T_asm);
4848
4849         statement_t *statement          = allocate_statement_zero(STATEMENT_ASM);
4850         statement->base.source_position = token.source_position;
4851
4852         asm_statement_t *asm_statement = &statement->asms;
4853
4854         if(token.type == T_volatile) {
4855                 next_token();
4856                 asm_statement->is_volatile = true;
4857         }
4858
4859         expect('(');
4860         asm_statement->asm_text = parse_string_literals();
4861
4862         if(token.type != ':')
4863                 goto end_of_asm;
4864         eat(':');
4865
4866         asm_statement->inputs = parse_asm_constraints();
4867         if(token.type != ':')
4868                 goto end_of_asm;
4869         eat(':');
4870
4871         asm_statement->outputs = parse_asm_constraints();
4872         if(token.type != ':')
4873                 goto end_of_asm;
4874         eat(':');
4875
4876         asm_statement->clobbers = parse_asm_clobbers();
4877
4878 end_of_asm:
4879         expect(')');
4880         expect(';');
4881         return statement;
4882 }
4883
4884 /**
4885  * Parse a case statement.
4886  */
4887 static statement_t *parse_case_statement(void)
4888 {
4889         eat(T_case);
4890
4891         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
4892
4893         statement->base.source_position  = token.source_position;
4894         statement->case_label.expression = parse_expression();
4895
4896         expect(':');
4897
4898         if (! is_constant_expression(statement->case_label.expression)) {
4899                 errorf(statement->base.source_position,
4900                         "case label does not reduce to an integer constant");
4901         } else {
4902                 /* TODO: check if the case label is already known */
4903                 if (current_switch != NULL) {
4904                         /* link all cases into the switch statement */
4905                         if (current_switch->last_case == NULL) {
4906                                 current_switch->first_case =
4907                                 current_switch->last_case  = &statement->case_label;
4908                         } else {
4909                                 current_switch->last_case->next = &statement->case_label;
4910                         }
4911                 } else {
4912                         errorf(statement->base.source_position,
4913                                 "case label not within a switch statement");
4914                 }
4915         }
4916         statement->case_label.label_statement = parse_statement();
4917
4918         return statement;
4919 }
4920
4921 /**
4922  * Finds an existing default label of a switch statement.
4923  */
4924 static case_label_statement_t *
4925 find_default_label(const switch_statement_t *statement)
4926 {
4927         for (case_label_statement_t *label = statement->first_case;
4928              label != NULL;
4929                  label = label->next) {
4930                 if (label->expression == NULL)
4931                         return label;
4932         }
4933         return NULL;
4934 }
4935
4936 /**
4937  * Parse a default statement.
4938  */
4939 static statement_t *parse_default_statement(void)
4940 {
4941         eat(T_default);
4942
4943         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
4944
4945         statement->base.source_position = token.source_position;
4946
4947         expect(':');
4948         if (current_switch != NULL) {
4949                 const case_label_statement_t *def_label = find_default_label(current_switch);
4950                 if (def_label != NULL) {
4951                         errorf(HERE, "multiple default labels in one switch");
4952                         errorf(def_label->statement.source_position,
4953                                 "this is the first default label");
4954                 } else {
4955                         /* link all cases into the switch statement */
4956                         if (current_switch->last_case == NULL) {
4957                                 current_switch->first_case =
4958                                         current_switch->last_case  = &statement->case_label;
4959                         } else {
4960                                 current_switch->last_case->next = &statement->case_label;
4961                         }
4962                 }
4963         } else {
4964                 errorf(statement->base.source_position,
4965                         "'default' label not within a switch statement");
4966         }
4967         statement->label.label_statement = parse_statement();
4968
4969         return statement;
4970 }
4971
4972 /**
4973  * Return the declaration for a given label symbol or create a new one.
4974  */
4975 static declaration_t *get_label(symbol_t *symbol)
4976 {
4977         declaration_t *candidate = get_declaration(symbol, NAMESPACE_LABEL);
4978         assert(current_function != NULL);
4979         /* if we found a label in the same function, then we already created the
4980          * declaration */
4981         if(candidate != NULL
4982                         && candidate->parent_context == &current_function->context) {
4983                 return candidate;
4984         }
4985
4986         /* otherwise we need to create a new one */
4987         declaration_t *const declaration = allocate_declaration_zero();
4988         declaration->namespc       = NAMESPACE_LABEL;
4989         declaration->symbol        = symbol;
4990
4991         label_push(declaration);
4992
4993         return declaration;
4994 }
4995
4996 /**
4997  * Parse a label statement.
4998  */
4999 static statement_t *parse_label_statement(void)
5000 {
5001         assert(token.type == T_IDENTIFIER);
5002         symbol_t *symbol = token.v.symbol;
5003         next_token();
5004
5005         declaration_t *label = get_label(symbol);
5006
5007         /* if source position is already set then the label is defined twice,
5008          * otherwise it was just mentioned in a goto so far */
5009         if(label->source_position.input_name != NULL) {
5010                 errorf(HERE, "duplicate label '%Y'", symbol);
5011                 errorf(label->source_position, "previous definition of '%Y' was here",
5012                        symbol);
5013         } else {
5014                 label->source_position = token.source_position;
5015         }
5016
5017         label_statement_t *label_statement = allocate_ast_zero(sizeof(label[0]));
5018
5019         label_statement->statement.kind            = STATEMENT_LABEL;
5020         label_statement->statement.source_position = token.source_position;
5021         label_statement->label                     = label;
5022
5023         eat(':');
5024
5025         if(token.type == '}') {
5026                 /* TODO only warn? */
5027                 errorf(HERE, "label at end of compound statement");
5028                 return (statement_t*) label_statement;
5029         } else {
5030                 if (token.type == ';') {
5031                         /* eat an empty statement here, to avoid the warning about an empty
5032                          * after a label.  label:; is commonly used to have a label before
5033                          * a }. */
5034                         next_token();
5035                 } else {
5036                         label_statement->label_statement = parse_statement();
5037                 }
5038         }
5039
5040         return (statement_t*) label_statement;
5041 }
5042
5043 /**
5044  * Parse an if statement.
5045  */
5046 static statement_t *parse_if(void)
5047 {
5048         eat(T_if);
5049
5050         if_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5051         statement->statement.kind            = STATEMENT_IF;
5052         statement->statement.source_position = token.source_position;
5053
5054         expect('(');
5055         statement->condition = parse_expression();
5056         expect(')');
5057
5058         statement->true_statement = parse_statement();
5059         if(token.type == T_else) {
5060                 next_token();
5061                 statement->false_statement = parse_statement();
5062         }
5063
5064         return (statement_t*) statement;
5065 }
5066
5067 /**
5068  * Parse a switch statement.
5069  */
5070 static statement_t *parse_switch(void)
5071 {
5072         eat(T_switch);
5073
5074         switch_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5075         statement->statement.kind            = STATEMENT_SWITCH;
5076         statement->statement.source_position = token.source_position;
5077
5078         expect('(');
5079         expression_t *const expr = parse_expression();
5080         type_t       *      type = skip_typeref(expr->base.datatype);
5081         if (is_type_integer(type)) {
5082                 type = promote_integer(type);
5083         } else if (is_type_valid(type)) {
5084                 errorf(expr->base.source_position, "switch quantity is not an integer, but '%T'", type);
5085                 type = type_error_type;
5086         }
5087         statement->expression = create_implicit_cast(expr, type);
5088         expect(')');
5089
5090         switch_statement_t *rem = current_switch;
5091         current_switch  = statement;
5092         statement->body = parse_statement();
5093         current_switch  = rem;
5094
5095         if (warning.switch_default && find_default_label(statement) == NULL) {
5096                 warningf(statement->statement.source_position, "switch has no default case");
5097         }
5098
5099         return (statement_t*) statement;
5100 }
5101
5102 static statement_t *parse_loop_body(statement_t *const loop)
5103 {
5104         statement_t *const rem = current_loop;
5105         current_loop = loop;
5106         statement_t *const body = parse_statement();
5107         current_loop = rem;
5108         return body;
5109 }
5110
5111 /**
5112  * Parse a while statement.
5113  */
5114 static statement_t *parse_while(void)
5115 {
5116         eat(T_while);
5117
5118         while_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5119         statement->statement.kind            = STATEMENT_WHILE;
5120         statement->statement.source_position = token.source_position;
5121
5122         expect('(');
5123         statement->condition = parse_expression();
5124         expect(')');
5125
5126         statement->body = parse_loop_body((statement_t*)statement);
5127
5128         return (statement_t*) statement;
5129 }
5130
5131 /**
5132  * Parse a do statement.
5133  */
5134 static statement_t *parse_do(void)
5135 {
5136         eat(T_do);
5137
5138         do_while_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5139         statement->statement.kind            = STATEMENT_DO_WHILE;
5140         statement->statement.source_position = token.source_position;
5141
5142         statement->body = parse_loop_body((statement_t*)statement);
5143         expect(T_while);
5144         expect('(');
5145         statement->condition = parse_expression();
5146         expect(')');
5147         expect(';');
5148
5149         return (statement_t*) statement;
5150 }
5151
5152 /**
5153  * Parse a for statement.
5154  */
5155 static statement_t *parse_for(void)
5156 {
5157         eat(T_for);
5158
5159         for_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5160         statement->statement.kind            = STATEMENT_FOR;
5161         statement->statement.source_position = token.source_position;
5162
5163         expect('(');
5164
5165         int         top          = environment_top();
5166         context_t  *last_context = context;
5167         set_context(&statement->context);
5168
5169         if(token.type != ';') {
5170                 if(is_declaration_specifier(&token, false)) {
5171                         parse_declaration(record_declaration);
5172                 } else {
5173                         statement->initialisation = parse_expression();
5174                         expect(';');
5175                 }
5176         } else {
5177                 expect(';');
5178         }
5179
5180         if(token.type != ';') {
5181                 statement->condition = parse_expression();
5182         }
5183         expect(';');
5184         if(token.type != ')') {
5185                 statement->step = parse_expression();
5186         }
5187         expect(')');
5188         statement->body = parse_loop_body((statement_t*)statement);
5189
5190         assert(context == &statement->context);
5191         set_context(last_context);
5192         environment_pop_to(top);
5193
5194         return (statement_t*) statement;
5195 }
5196
5197 /**
5198  * Parse a goto statement.
5199  */
5200 static statement_t *parse_goto(void)
5201 {
5202         eat(T_goto);
5203
5204         if(token.type != T_IDENTIFIER) {
5205                 parse_error_expected("while parsing goto", T_IDENTIFIER, 0);
5206                 eat_statement();
5207                 return NULL;
5208         }
5209         symbol_t *symbol = token.v.symbol;
5210         next_token();
5211
5212         declaration_t *label = get_label(symbol);
5213
5214         goto_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5215
5216         statement->statement.kind            = STATEMENT_GOTO;
5217         statement->statement.source_position = token.source_position;
5218
5219         statement->label = label;
5220
5221         /* remember the goto's in a list for later checking */
5222         if (goto_last == NULL) {
5223                 goto_first = goto_last = statement;
5224         } else {
5225                 goto_last->next = statement;
5226         }
5227
5228         expect(';');
5229
5230         return (statement_t*) statement;
5231 }
5232
5233 /**
5234  * Parse a continue statement.
5235  */
5236 static statement_t *parse_continue(void)
5237 {
5238         statement_t *statement;
5239         if (current_loop == NULL) {
5240                 errorf(HERE, "continue statement not within loop");
5241                 statement = NULL;
5242         } else {
5243                 statement = allocate_statement_zero(STATEMENT_CONTINUE);
5244
5245                 statement->base.source_position = token.source_position;
5246         }
5247
5248         eat(T_continue);
5249         expect(';');
5250
5251         return statement;
5252 }
5253
5254 /**
5255  * Parse a break statement.
5256  */
5257 static statement_t *parse_break(void)
5258 {
5259         statement_t *statement;
5260         if (current_switch == NULL && current_loop == NULL) {
5261                 errorf(HERE, "break statement not within loop or switch");
5262                 statement = NULL;
5263         } else {
5264                 statement = allocate_statement_zero(STATEMENT_BREAK);
5265
5266                 statement->base.source_position = token.source_position;
5267         }
5268
5269         eat(T_break);
5270         expect(';');
5271
5272         return statement;
5273 }
5274
5275 /**
5276  * Check if a given declaration represents a local variable.
5277  */
5278 static bool is_local_var_declaration(const declaration_t *declaration) {
5279         switch ((storage_class_tag_t) declaration->storage_class) {
5280         case STORAGE_CLASS_NONE:
5281         case STORAGE_CLASS_AUTO:
5282         case STORAGE_CLASS_REGISTER: {
5283                 const type_t *type = skip_typeref(declaration->type);
5284                 if(is_type_function(type)) {
5285                         return false;
5286                 } else {
5287                         return true;
5288                 }
5289         }
5290         default:
5291                 return false;
5292         }
5293 }
5294
5295 /**
5296  * Check if a given expression represents a local variable.
5297  */
5298 static bool is_local_variable(const expression_t *expression)
5299 {
5300         if (expression->base.kind != EXPR_REFERENCE) {
5301                 return false;
5302         }
5303         const declaration_t *declaration = expression->reference.declaration;
5304         return is_local_var_declaration(declaration);
5305 }
5306
5307 /**
5308  * Parse a return statement.
5309  */
5310 static statement_t *parse_return(void)
5311 {
5312         eat(T_return);
5313
5314         return_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
5315
5316         statement->statement.kind            = STATEMENT_RETURN;
5317         statement->statement.source_position = token.source_position;
5318
5319         expression_t *return_value = NULL;
5320         if(token.type != ';') {
5321                 return_value = parse_expression();
5322         }
5323         expect(';');
5324
5325         const type_t *const func_type = current_function->type;
5326         assert(is_type_function(func_type));
5327         type_t *const return_type = skip_typeref(func_type->function.return_type);
5328
5329         if(return_value != NULL) {
5330                 type_t *return_value_type = skip_typeref(return_value->base.datatype);
5331
5332                 if(is_type_atomic(return_type, ATOMIC_TYPE_VOID)
5333                                 && !is_type_atomic(return_value_type, ATOMIC_TYPE_VOID)) {
5334                         warningf(statement->statement.source_position,
5335                                 "'return' with a value, in function returning void");
5336                         return_value = NULL;
5337                 } else {
5338                         type_t *const res_type = semantic_assign(return_type,
5339                                 return_value, "'return'");
5340                         if (res_type == NULL) {
5341                                 errorf(statement->statement.source_position,
5342                                         "cannot return something of type '%T' in function returning '%T'",
5343                                         return_value->base.datatype, return_type);
5344                         } else {
5345                                 return_value = create_implicit_cast(return_value, res_type);
5346                         }
5347                 }
5348                 /* check for returning address of a local var */
5349                 if (return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
5350                         const expression_t *expression = return_value->unary.value;
5351                         if (is_local_variable(expression)) {
5352                                 warningf(statement->statement.source_position,
5353                                         "function returns address of local variable");
5354                         }
5355                 }
5356         } else {
5357                 if(!is_type_atomic(return_type, ATOMIC_TYPE_VOID)) {
5358                         warningf(statement->statement.source_position,
5359                                 "'return' without value, in function returning non-void");
5360                 }
5361         }
5362         statement->return_value = return_value;
5363
5364         return (statement_t*) statement;
5365 }
5366
5367 /**
5368  * Parse a declaration statement.
5369  */
5370 static statement_t *parse_declaration_statement(void)
5371 {
5372         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
5373
5374         statement->base.source_position = token.source_position;
5375
5376         declaration_t *before = last_declaration;
5377         parse_declaration(record_declaration);
5378
5379         if(before == NULL) {
5380                 statement->declaration.declarations_begin = context->declarations;
5381         } else {
5382                 statement->declaration.declarations_begin = before->next;
5383         }
5384         statement->declaration.declarations_end = last_declaration;
5385
5386         return statement;
5387 }
5388
5389 /**
5390  * Parse an expression statement, ie. expr ';'.
5391  */
5392 static statement_t *parse_expression_statement(void)
5393 {
5394         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
5395
5396         statement->base.source_position  = token.source_position;
5397         expression_t *const expr         = parse_expression();
5398         statement->expression.expression = expr;
5399
5400         if (warning.unused_value  && !expression_has_effect(expr)) {
5401                 warningf(expr->base.source_position, "statement has no effect");
5402         }
5403
5404         expect(';');
5405
5406         return statement;
5407 }
5408
5409 /**
5410  * Parse a statement.
5411  */
5412 static statement_t *parse_statement(void)
5413 {
5414         statement_t   *statement = NULL;
5415
5416         /* declaration or statement */
5417         switch(token.type) {
5418         case T_asm:
5419                 statement = parse_asm_statement();
5420                 break;
5421
5422         case T_case:
5423                 statement = parse_case_statement();
5424                 break;
5425
5426         case T_default:
5427                 statement = parse_default_statement();
5428                 break;
5429
5430         case '{':
5431                 statement = parse_compound_statement();
5432                 break;
5433
5434         case T_if:
5435                 statement = parse_if();
5436                 break;
5437
5438         case T_switch:
5439                 statement = parse_switch();
5440                 break;
5441
5442         case T_while:
5443                 statement = parse_while();
5444                 break;
5445
5446         case T_do:
5447                 statement = parse_do();
5448                 break;
5449
5450         case T_for:
5451                 statement = parse_for();
5452                 break;
5453
5454         case T_goto:
5455                 statement = parse_goto();
5456                 break;
5457
5458         case T_continue:
5459                 statement = parse_continue();
5460                 break;
5461
5462         case T_break:
5463                 statement = parse_break();
5464                 break;
5465
5466         case T_return:
5467                 statement = parse_return();
5468                 break;
5469
5470         case ';':
5471                 if (warning.empty_statement) {
5472                         warningf(HERE, "statement is empty");
5473                 }
5474                 next_token();
5475                 statement = NULL;
5476                 break;
5477
5478         case T_IDENTIFIER:
5479                 if(look_ahead(1)->type == ':') {
5480                         statement = parse_label_statement();
5481                         break;
5482                 }
5483
5484                 if(is_typedef_symbol(token.v.symbol)) {
5485                         statement = parse_declaration_statement();
5486                         break;
5487                 }
5488
5489                 statement = parse_expression_statement();
5490                 break;
5491
5492         case T___extension__:
5493                 /* this can be a prefix to a declaration or an expression statement */
5494                 /* we simply eat it now and parse the rest with tail recursion */
5495                 do {
5496                         next_token();
5497                 } while(token.type == T___extension__);
5498                 statement = parse_statement();
5499                 break;
5500
5501         DECLARATION_START
5502                 statement = parse_declaration_statement();
5503                 break;
5504
5505         default:
5506                 statement = parse_expression_statement();
5507                 break;
5508         }
5509
5510         assert(statement == NULL
5511                         || statement->base.source_position.input_name != NULL);
5512
5513         return statement;
5514 }
5515
5516 /**
5517  * Parse a compound statement.
5518  */
5519 static statement_t *parse_compound_statement(void)
5520 {
5521         compound_statement_t *const compound_statement
5522                 = allocate_ast_zero(sizeof(compound_statement[0]));
5523         compound_statement->statement.kind            = STATEMENT_COMPOUND;
5524         compound_statement->statement.source_position = token.source_position;
5525
5526         eat('{');
5527
5528         int        top          = environment_top();
5529         context_t *last_context = context;
5530         set_context(&compound_statement->context);
5531
5532         statement_t *last_statement = NULL;
5533
5534         while(token.type != '}' && token.type != T_EOF) {
5535                 statement_t *statement = parse_statement();
5536                 if(statement == NULL)
5537                         continue;
5538
5539                 if(last_statement != NULL) {
5540                         last_statement->base.next = statement;
5541                 } else {
5542                         compound_statement->statements = statement;
5543                 }
5544
5545                 while(statement->base.next != NULL)
5546                         statement = statement->base.next;
5547
5548                 last_statement = statement;
5549         }
5550
5551         if(token.type == '}') {
5552                 next_token();
5553         } else {
5554                 errorf(compound_statement->statement.source_position, "end of file while looking for closing '}'");
5555         }
5556
5557         assert(context == &compound_statement->context);
5558         set_context(last_context);
5559         environment_pop_to(top);
5560
5561         return (statement_t*) compound_statement;
5562 }
5563
5564 /**
5565  * Initialize builtin types.
5566  */
5567 static void initialize_builtin_types(void)
5568 {
5569         type_intmax_t    = make_global_typedef("__intmax_t__",      type_long_long);
5570         type_size_t      = make_global_typedef("__SIZE_TYPE__",     type_unsigned_long);
5571         type_ssize_t     = make_global_typedef("__SSIZE_TYPE__",    type_long);
5572         type_ptrdiff_t   = make_global_typedef("__PTRDIFF_TYPE__",  type_long);
5573         type_uintmax_t   = make_global_typedef("__uintmax_t__",     type_unsigned_long_long);
5574         type_uptrdiff_t  = make_global_typedef("__UPTRDIFF_TYPE__", type_unsigned_long);
5575         type_wchar_t     = make_global_typedef("__WCHAR_TYPE__",    type_int);
5576         type_wint_t      = make_global_typedef("__WINT_TYPE__",     type_int);
5577
5578         type_intmax_t_ptr  = make_pointer_type(type_intmax_t,  TYPE_QUALIFIER_NONE);
5579         type_ptrdiff_t_ptr = make_pointer_type(type_ptrdiff_t, TYPE_QUALIFIER_NONE);
5580         type_ssize_t_ptr   = make_pointer_type(type_ssize_t,   TYPE_QUALIFIER_NONE);
5581         type_wchar_t_ptr   = make_pointer_type(type_wchar_t,   TYPE_QUALIFIER_NONE);
5582 }
5583
5584 /**
5585  * Parse a translation unit.
5586  */
5587 static translation_unit_t *parse_translation_unit(void)
5588 {
5589         translation_unit_t *unit = allocate_ast_zero(sizeof(unit[0]));
5590
5591         assert(global_context == NULL);
5592         global_context = &unit->context;
5593
5594         assert(context == NULL);
5595         set_context(&unit->context);
5596
5597         initialize_builtin_types();
5598
5599         while(token.type != T_EOF) {
5600                 if (token.type == ';') {
5601                         /* TODO error in strict mode */
5602                         warningf(HERE, "stray ';' outside of function");
5603                         next_token();
5604                 } else {
5605                         parse_external_declaration();
5606                 }
5607         }
5608
5609         assert(context == &unit->context);
5610         context          = NULL;
5611         last_declaration = NULL;
5612
5613         assert(global_context == &unit->context);
5614         global_context = NULL;
5615
5616         return unit;
5617 }
5618
5619 /**
5620  * Parse the input.
5621  *
5622  * @return  the translation unit or NULL if errors occurred.
5623  */
5624 translation_unit_t *parse(void)
5625 {
5626         environment_stack = NEW_ARR_F(stack_entry_t, 0);
5627         label_stack       = NEW_ARR_F(stack_entry_t, 0);
5628         diagnostic_count  = 0;
5629         error_count       = 0;
5630         warning_count     = 0;
5631
5632         type_set_output(stderr);
5633         ast_set_output(stderr);
5634
5635         lookahead_bufpos = 0;
5636         for(int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
5637                 next_token();
5638         }
5639         translation_unit_t *unit = parse_translation_unit();
5640
5641         DEL_ARR_F(environment_stack);
5642         DEL_ARR_F(label_stack);
5643
5644         if(error_count > 0)
5645                 return NULL;
5646
5647         return unit;
5648 }
5649
5650 /**
5651  * Initialize the parser.
5652  */
5653 void init_parser(void)
5654 {
5655         init_expression_parsers();
5656         obstack_init(&temp_obst);
5657
5658         symbol_t *const va_list_sym = symbol_table_insert("__builtin_va_list");
5659         type_valist = create_builtin_type(va_list_sym, type_void_ptr);
5660 }
5661
5662 /**
5663  * Terminate the parser.
5664  */
5665 void exit_parser(void)
5666 {
5667         obstack_free(&temp_obst, NULL);
5668 }