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