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(declaration_t));
 144         declaration->type = type_error_type;
 145         return declaration;
 146 }
 147
 148 /**
 149  * Returns the size of a statement node.
 150  *
 151  * @param kind  the statement kind
 152  */
 153 static size_t get_statement_struct_size(statement_kind_t kind)
 154 {
 155         static const size_t sizes[] = {
 156                 [STATEMENT_COMPOUND]    = sizeof(compound_statement_t),
 157                 [STATEMENT_RETURN]      = sizeof(return_statement_t),
 158                 [STATEMENT_DECLARATION] = sizeof(declaration_statement_t),
 159                 [STATEMENT_IF]          = sizeof(if_statement_t),
 160                 [STATEMENT_SWITCH]      = sizeof(switch_statement_t),
 161                 [STATEMENT_EXPRESSION]  = sizeof(expression_statement_t),
 162                 [STATEMENT_CONTINUE]    = sizeof(statement_base_t),
 163                 [STATEMENT_BREAK]       = sizeof(statement_base_t),
 164                 [STATEMENT_GOTO]        = sizeof(goto_statement_t),
 165                 [STATEMENT_LABEL]       = sizeof(label_statement_t),
 166                 [STATEMENT_CASE_LABEL]  = sizeof(case_label_statement_t),
 167                 [STATEMENT_WHILE]       = sizeof(while_statement_t),
 168                 [STATEMENT_DO_WHILE]    = sizeof(do_while_statement_t),
 169                 [STATEMENT_FOR]         = sizeof(for_statement_t),
 170                 [STATEMENT_ASM]         = sizeof(asm_statement_t)
 171         };
 172         assert(kind <= sizeof(sizes) / sizeof(sizes[0]));
 173         assert(sizes[kind] != 0);
 174         return sizes[kind];
 175 }
 176
 177 /**
 178  * Allocate a statement node of given kind and initialize all
 179  * fields with zero.
 180  */
 181 static statement_t *allocate_statement_zero(statement_kind_t kind)
 182 {
 183         size_t       size = get_statement_struct_size(kind);
 184         statement_t *res  = allocate_ast_zero(size);
 185
 186         res->base.kind = kind;
 187         return res;
 188 }
 189
 190 /**
 191  * Returns the size of an expression node.
 192  *
 193  * @param kind  the expression kind
 194  */
 195 static size_t get_expression_struct_size(expression_kind_t kind)
 196 {
 197         static const size_t sizes[] = {
 198                 [EXPR_INVALID]             = sizeof(expression_base_t),
 199                 [EXPR_REFERENCE]           = sizeof(reference_expression_t),
 200                 [EXPR_CONST]               = sizeof(const_expression_t),
 201                 [EXPR_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.type = 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.type   = 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.type);
 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.type;
 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.type;
 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.type;
 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.type, 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.type;
1427                 }
1428                 break;
1429
1430         TYPENAME_START
1431                 type = parse_typename();
1432                 break;
1433
1434         default:
1435                 expression = parse_expression();
1436                 type       = expression->base.type;
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->type            = NULL; /* a K&R parameter list has no types, yet */
1809                 declaration->source_position = token.source_position;
1810                 declaration->symbol          = token.v.symbol;
1811                 next_token();
1812
1813                 if(last_declaration != NULL) {
1814                         last_declaration->next = declaration;
1815                 } else {
1816                         declarations = declaration;
1817                 }
1818                 last_declaration = declaration;
1819
1820                 if(token.type != ',')
1821                         break;
1822                 next_token();
1823         } while(token.type == T_IDENTIFIER);
1824
1825         return declarations;
1826 }
1827
1828 static void semantic_parameter(declaration_t *declaration)
1829 {
1830         /* TODO: improve error messages */
1831
1832         if(declaration->storage_class == STORAGE_CLASS_TYPEDEF) {
1833                 errorf(HERE, "typedef not allowed in parameter list");
1834         } else if(declaration->storage_class != STORAGE_CLASS_NONE
1835                         && declaration->storage_class != STORAGE_CLASS_REGISTER) {
1836                 errorf(HERE, "parameter may only have none or register storage class");
1837         }
1838
1839         type_t *const orig_type = declaration->type;
1840         type_t *      type      = skip_typeref(orig_type);
1841
1842         /* Array as last part of a parameter type is just syntactic sugar.  Turn it
1843          * into a pointer. § 6.7.5.3 (7) */
1844         if (is_type_array(type)) {
1845                 type_t *const element_type = type->array.element_type;
1846
1847                 type = make_pointer_type(element_type, type->base.qualifiers);
1848
1849                 declaration->type = type;
1850         }
1851
1852         if(is_type_incomplete(type)) {
1853                 errorf(HERE, "incomplete type ('%T') not allowed for parameter '%Y'",
1854                        orig_type, declaration->symbol);
1855         }
1856 }
1857
1858 static declaration_t *parse_parameter(void)
1859 {
1860         declaration_specifiers_t specifiers;
1861         memset(&specifiers, 0, sizeof(specifiers));
1862
1863         parse_declaration_specifiers(&specifiers);
1864
1865         declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/true);
1866
1867         semantic_parameter(declaration);
1868
1869         return declaration;
1870 }
1871
1872 static declaration_t *parse_parameters(function_type_t *type)
1873 {
1874         if(token.type == T_IDENTIFIER) {
1875                 symbol_t *symbol = token.v.symbol;
1876                 if(!is_typedef_symbol(symbol)) {
1877                         type->kr_style_parameters = true;
1878                         return parse_identifier_list();
1879                 }
1880         }
1881
1882         if(token.type == ')') {
1883                 type->unspecified_parameters = 1;
1884                 return NULL;
1885         }
1886         if(token.type == T_void && look_ahead(1)->type == ')') {
1887                 next_token();
1888                 return NULL;
1889         }
1890
1891         declaration_t        *declarations = NULL;
1892         declaration_t        *declaration;
1893         declaration_t        *last_declaration = NULL;
1894         function_parameter_t *parameter;
1895         function_parameter_t *last_parameter = NULL;
1896
1897         while(true) {
1898                 switch(token.type) {
1899                 case T_DOTDOTDOT:
1900                         next_token();
1901                         type->variadic = 1;
1902                         return declarations;
1903
1904                 case T_IDENTIFIER:
1905                 case T___extension__:
1906                 DECLARATION_START
1907                         declaration = parse_parameter();
1908
1909                         parameter       = obstack_alloc(type_obst, sizeof(parameter[0]));
1910                         memset(parameter, 0, sizeof(parameter[0]));
1911                         parameter->type = declaration->type;
1912
1913                         if(last_parameter != NULL) {
1914                                 last_declaration->next = declaration;
1915                                 last_parameter->next   = parameter;
1916                         } else {
1917                                 type->parameters = parameter;
1918                                 declarations     = declaration;
1919                         }
1920                         last_parameter   = parameter;
1921                         last_declaration = declaration;
1922                         break;
1923
1924                 default:
1925                         return declarations;
1926                 }
1927                 if(token.type != ',')
1928                         return declarations;
1929                 next_token();
1930         }
1931 }
1932
1933 typedef enum {
1934         CONSTRUCT_INVALID,
1935         CONSTRUCT_POINTER,
1936         CONSTRUCT_FUNCTION,
1937         CONSTRUCT_ARRAY
1938 } construct_type_type_t;
1939
1940 typedef struct construct_type_t construct_type_t;
1941 struct construct_type_t {
1942         construct_type_type_t  type;
1943         construct_type_t      *next;
1944 };
1945
1946 typedef struct parsed_pointer_t parsed_pointer_t;
1947 struct parsed_pointer_t {
1948         construct_type_t  construct_type;
1949         type_qualifiers_t type_qualifiers;
1950 };
1951
1952 typedef struct construct_function_type_t construct_function_type_t;
1953 struct construct_function_type_t {
1954         construct_type_t  construct_type;
1955         type_t           *function_type;
1956 };
1957
1958 typedef struct parsed_array_t parsed_array_t;
1959 struct parsed_array_t {
1960         construct_type_t  construct_type;
1961         type_qualifiers_t type_qualifiers;
1962         bool              is_static;
1963         bool              is_variable;
1964         expression_t     *size;
1965 };
1966
1967 typedef struct construct_base_type_t construct_base_type_t;
1968 struct construct_base_type_t {
1969         construct_type_t  construct_type;
1970         type_t           *type;
1971 };
1972
1973 static construct_type_t *parse_pointer_declarator(void)
1974 {
1975         eat('*');
1976
1977         parsed_pointer_t *pointer = obstack_alloc(&temp_obst, sizeof(pointer[0]));
1978         memset(pointer, 0, sizeof(pointer[0]));
1979         pointer->construct_type.type = CONSTRUCT_POINTER;
1980         pointer->type_qualifiers     = parse_type_qualifiers();
1981
1982         return (construct_type_t*) pointer;
1983 }
1984
1985 static construct_type_t *parse_array_declarator(void)
1986 {
1987         eat('[');
1988
1989         parsed_array_t *array = obstack_alloc(&temp_obst, sizeof(array[0]));
1990         memset(array, 0, sizeof(array[0]));
1991         array->construct_type.type = CONSTRUCT_ARRAY;
1992
1993         if(token.type == T_static) {
1994                 array->is_static = true;
1995                 next_token();
1996         }
1997
1998         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
1999         if(type_qualifiers != 0) {
2000                 if(token.type == T_static) {
2001                         array->is_static = true;
2002                         next_token();
2003                 }
2004         }
2005         array->type_qualifiers = type_qualifiers;
2006
2007         if(token.type == '*' && look_ahead(1)->type == ']') {
2008                 array->is_variable = true;
2009                 next_token();
2010         } else if(token.type != ']') {
2011                 array->size = parse_assignment_expression();
2012         }
2013
2014         expect(']');
2015
2016         return (construct_type_t*) array;
2017 }
2018
2019 static construct_type_t *parse_function_declarator(declaration_t *declaration)
2020 {
2021         eat('(');
2022
2023         type_t *type = allocate_type_zero(TYPE_FUNCTION);
2024
2025         declaration_t *parameters = parse_parameters(&type->function);
2026         if(declaration != NULL) {
2027                 declaration->scope.declarations = parameters;
2028         }
2029
2030         construct_function_type_t *construct_function_type =
2031                 obstack_alloc(&temp_obst, sizeof(construct_function_type[0]));
2032         memset(construct_function_type, 0, sizeof(construct_function_type[0]));
2033         construct_function_type->construct_type.type = CONSTRUCT_FUNCTION;
2034         construct_function_type->function_type       = type;
2035
2036         expect(')');
2037
2038         return (construct_type_t*) construct_function_type;
2039 }
2040
2041 static construct_type_t *parse_inner_declarator(declaration_t *declaration,
2042                 bool may_be_abstract)
2043 {
2044         /* construct a single linked list of construct_type_t's which describe
2045          * how to construct the final declarator type */
2046         construct_type_t *first = NULL;
2047         construct_type_t *last  = NULL;
2048
2049         /* pointers */
2050         while(token.type == '*') {
2051                 construct_type_t *type = parse_pointer_declarator();
2052
2053                 if(last == NULL) {
2054                         first = type;
2055                         last  = type;
2056                 } else {
2057                         last->next = type;
2058                         last       = type;
2059                 }
2060         }
2061
2062         /* TODO: find out if this is correct */
2063         parse_attributes();
2064
2065         construct_type_t *inner_types = NULL;
2066
2067         switch(token.type) {
2068         case T_IDENTIFIER:
2069                 if(declaration == NULL) {
2070                         errorf(HERE, "no identifier expected in typename");
2071                 } else {
2072                         declaration->symbol          = token.v.symbol;
2073                         declaration->source_position = token.source_position;
2074                 }
2075                 next_token();
2076                 break;
2077         case '(':
2078                 next_token();
2079                 inner_types = parse_inner_declarator(declaration, may_be_abstract);
2080                 expect(')');
2081                 break;
2082         default:
2083                 if(may_be_abstract)
2084                         break;
2085                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', 0);
2086                 /* avoid a loop in the outermost scope, because eat_statement doesn't
2087                  * eat '}' */
2088                 if(token.type == '}' && current_function == NULL) {
2089                         next_token();
2090                 } else {
2091                         eat_statement();
2092                 }
2093                 return NULL;
2094         }
2095
2096         construct_type_t *p = last;
2097
2098         while(true) {
2099                 construct_type_t *type;
2100                 switch(token.type) {
2101                 case '(':
2102                         type = parse_function_declarator(declaration);
2103                         break;
2104                 case '[':
2105                         type = parse_array_declarator();
2106                         break;
2107                 default:
2108                         goto declarator_finished;
2109                 }
2110
2111                 /* insert in the middle of the list (behind p) */
2112                 if(p != NULL) {
2113                         type->next = p->next;
2114                         p->next    = type;
2115                 } else {
2116                         type->next = first;
2117                         first      = type;
2118                 }
2119                 if(last == p) {
2120                         last = type;
2121                 }
2122         }
2123
2124 declarator_finished:
2125         parse_attributes();
2126
2127         /* append inner_types at the end of the list, we don't to set last anymore
2128          * as it's not needed anymore */
2129         if(last == NULL) {
2130                 assert(first == NULL);
2131                 first = inner_types;
2132         } else {
2133                 last->next = inner_types;
2134         }
2135
2136         return first;
2137 }
2138
2139 static type_t *construct_declarator_type(construct_type_t *construct_list,
2140                                          type_t *type)
2141 {
2142         construct_type_t *iter = construct_list;
2143         for( ; iter != NULL; iter = iter->next) {
2144                 switch(iter->type) {
2145                 case CONSTRUCT_INVALID:
2146                         panic("invalid type construction found");
2147                 case CONSTRUCT_FUNCTION: {
2148                         construct_function_type_t *construct_function_type
2149                                 = (construct_function_type_t*) iter;
2150
2151                         type_t *function_type = construct_function_type->function_type;
2152
2153                         function_type->function.return_type = type;
2154
2155                         type_t *skipped_return_type = skip_typeref(type);
2156                         if (is_type_function(skipped_return_type)) {
2157                                 errorf(HERE, "function returning function is not allowed");
2158                                 type = type_error_type;
2159                         } else if (is_type_array(skipped_return_type)) {
2160                                 errorf(HERE, "function returning array is not allowed");
2161                                 type = type_error_type;
2162                         } else {
2163                                 type = function_type;
2164                         }
2165                         break;
2166                 }
2167
2168                 case CONSTRUCT_POINTER: {
2169                         parsed_pointer_t *parsed_pointer = (parsed_pointer_t*) iter;
2170                         type_t           *pointer_type   = allocate_type_zero(TYPE_POINTER);
2171                         pointer_type->pointer.points_to  = type;
2172                         pointer_type->base.qualifiers    = parsed_pointer->type_qualifiers;
2173
2174                         type = pointer_type;
2175                         break;
2176                 }
2177
2178                 case CONSTRUCT_ARRAY: {
2179                         parsed_array_t *parsed_array  = (parsed_array_t*) iter;
2180                         type_t         *array_type    = allocate_type_zero(TYPE_ARRAY);
2181
2182                         array_type->base.qualifiers    = parsed_array->type_qualifiers;
2183                         array_type->array.element_type = type;
2184                         array_type->array.is_static    = parsed_array->is_static;
2185                         array_type->array.is_variable  = parsed_array->is_variable;
2186                         array_type->array.size         = parsed_array->size;
2187
2188                         type_t *skipped_type = skip_typeref(type);
2189                         if (is_type_atomic(skipped_type, ATOMIC_TYPE_VOID)) {
2190                                 errorf(HERE, "array of void is not allowed");
2191                                 type = type_error_type;
2192                         } else {
2193                                 type = array_type;
2194                         }
2195                         break;
2196                 }
2197                 }
2198
2199                 type_t *hashed_type = typehash_insert(type);
2200                 if(hashed_type != type) {
2201                         /* the function type was constructed earlier freeing it here will
2202                          * destroy other types... */
2203                         if(iter->type != CONSTRUCT_FUNCTION) {
2204                                 free_type(type);
2205                         }
2206                         type = hashed_type;
2207                 }
2208         }
2209
2210         return type;
2211 }
2212
2213 static declaration_t *parse_declarator(
2214                 const declaration_specifiers_t *specifiers, bool may_be_abstract)
2215 {
2216         declaration_t *const declaration = allocate_declaration_zero();
2217         declaration->storage_class  = specifiers->storage_class;
2218         declaration->modifiers      = specifiers->decl_modifiers;
2219         declaration->is_inline      = specifiers->is_inline;
2220
2221         construct_type_t *construct_type
2222                 = parse_inner_declarator(declaration, may_be_abstract);
2223         type_t *const type = specifiers->type;
2224         declaration->type = construct_declarator_type(construct_type, type);
2225
2226         if(construct_type != NULL) {
2227                 obstack_free(&temp_obst, construct_type);
2228         }
2229
2230         return declaration;
2231 }
2232
2233 static type_t *parse_abstract_declarator(type_t *base_type)
2234 {
2235         construct_type_t *construct_type = parse_inner_declarator(NULL, 1);
2236
2237         type_t *result = construct_declarator_type(construct_type, base_type);
2238         if(construct_type != NULL) {
2239                 obstack_free(&temp_obst, construct_type);
2240         }
2241
2242         return result;
2243 }
2244
2245 static declaration_t *append_declaration(declaration_t* const declaration)
2246 {
2247         if (last_declaration != NULL) {
2248                 last_declaration->next = declaration;
2249         } else {
2250                 scope->declarations = declaration;
2251         }
2252         last_declaration = declaration;
2253         return declaration;
2254 }
2255
2256 /**
2257  * Check if the declaration of main is suspicious.  main should be a
2258  * function with external linkage, returning int, taking either zero
2259  * arguments, two, or three arguments of appropriate types, ie.
2260  *
2261  * int main([ int argc, char **argv [, char **env ] ]).
2262  *
2263  * @param decl    the declaration to check
2264  * @param type    the function type of the declaration
2265  */
2266 static void check_type_of_main(const declaration_t *const decl, const function_type_t *const func_type)
2267 {
2268         if (decl->storage_class == STORAGE_CLASS_STATIC) {
2269                 warningf(decl->source_position, "'main' is normally a non-static function");
2270         }
2271         if (skip_typeref(func_type->return_type) != type_int) {
2272                 warningf(decl->source_position, "return type of 'main' should be 'int', but is '%T'", func_type->return_type);
2273         }
2274         const function_parameter_t *parm = func_type->parameters;
2275         if (parm != NULL) {
2276                 type_t *const first_type = parm->type;
2277                 if (!types_compatible(skip_typeref(first_type), type_int)) {
2278                         warningf(decl->source_position, "first argument of 'main' should be 'int', but is '%T'", first_type);
2279                 }
2280                 parm = parm->next;
2281                 if (parm != NULL) {
2282                         type_t *const second_type = parm->type;
2283                         if (!types_compatible(skip_typeref(second_type), type_char_ptr_ptr)) {
2284                                 warningf(decl->source_position, "second argument of 'main' should be 'char**', but is '%T'", second_type);
2285                         }
2286                         parm = parm->next;
2287                         if (parm != NULL) {
2288                                 type_t *const third_type = parm->type;
2289                                 if (!types_compatible(skip_typeref(third_type), type_char_ptr_ptr)) {
2290                                         warningf(decl->source_position, "third argument of 'main' should be 'char**', but is '%T'", third_type);
2291                                 }
2292                                 parm = parm->next;
2293                                 if (parm != NULL) {
2294                                         warningf(decl->source_position, "'main' takes only zero, two or three arguments");
2295                                 }
2296                         }
2297                 } else {
2298                         warningf(decl->source_position, "'main' takes only zero, two or three arguments");
2299                 }
2300         }
2301 }
2302
2303 /**
2304  * Check if a symbol is the equal to "main".
2305  */
2306 static bool is_sym_main(const symbol_t *const sym)
2307 {
2308         return strcmp(sym->string, "main") == 0;
2309 }
2310
2311 static declaration_t *internal_record_declaration(
2312         declaration_t *const declaration,
2313         const bool is_function_definition)
2314 {
2315         const symbol_t *const symbol  = declaration->symbol;
2316         const namespace_t     namespc = (namespace_t)declaration->namespc;
2317
2318         type_t       *const orig_type = declaration->type;
2319         const type_t *const type      = skip_typeref(orig_type);
2320         if (is_type_function(type) &&
2321                         type->function.unspecified_parameters &&
2322                         warning.strict_prototypes) {
2323                 warningf(declaration->source_position,
2324                          "function declaration '%#T' is not a prototype",
2325                          orig_type, declaration->symbol);
2326         }
2327
2328         if (is_function_definition && warning.main && is_sym_main(symbol)) {
2329                 check_type_of_main(declaration, &type->function);
2330         }
2331
2332         declaration_t *const previous_declaration = get_declaration(symbol, namespc);
2333         assert(declaration != previous_declaration);
2334         if (previous_declaration != NULL) {
2335                 if (previous_declaration->parent_scope == scope) {
2336                         /* can happen for K&R style declarations */
2337                         if(previous_declaration->type == NULL) {
2338                                 previous_declaration->type = declaration->type;
2339                         }
2340
2341                         const type_t *const prev_type = skip_typeref(previous_declaration->type);
2342                         if (!types_compatible(type, prev_type)) {
2343                                 errorf(declaration->source_position,
2344                                         "declaration '%#T' is incompatible with previous declaration '%#T'",
2345                                         orig_type, symbol, previous_declaration->type, symbol);
2346                                 errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
2347                         } else {
2348                                 unsigned old_storage_class = previous_declaration->storage_class;
2349                                 unsigned new_storage_class = declaration->storage_class;
2350
2351                                 /* pretend no storage class means extern for function declarations
2352                                  * (except if the previous declaration is neither none nor extern) */
2353                                 if (is_type_function(type)) {
2354                                         switch (old_storage_class) {
2355                                                 case STORAGE_CLASS_NONE:
2356                                                         old_storage_class = STORAGE_CLASS_EXTERN;
2357
2358                                                 case STORAGE_CLASS_EXTERN:
2359                                                         if (is_function_definition) {
2360                                                                 if (warning.missing_prototypes &&
2361                                                                     prev_type->function.unspecified_parameters &&
2362                                                                     !is_sym_main(symbol)) {
2363                                                                         warningf(declaration->source_position, "no previous prototype for '%#T'", orig_type, symbol);
2364                                                                 }
2365                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
2366                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
2367                                                         }
2368                                                         break;
2369
2370                                                 default: break;
2371                                         }
2372                                 }
2373
2374                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
2375                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
2376 warn_redundant_declaration:
2377                                         if (warning.redundant_decls) {
2378                                                 warningf(declaration->source_position, "redundant declaration for '%Y'", symbol);
2379                                                 warningf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
2380                                         }
2381                                 } else if (current_function == NULL) {
2382                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
2383                                                         new_storage_class == STORAGE_CLASS_STATIC) {
2384                                                 errorf(declaration->source_position, "static declaration of '%Y' follows non-static declaration", symbol);
2385                                                 errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
2386                                         } else {
2387                                                 if (old_storage_class != STORAGE_CLASS_EXTERN && !is_function_definition) {
2388                                                         goto warn_redundant_declaration;
2389                                                 }
2390                                                 if (new_storage_class == STORAGE_CLASS_NONE) {
2391                                                         previous_declaration->storage_class = STORAGE_CLASS_NONE;
2392                                                 }
2393                                         }
2394                                 } else {
2395                                         if (old_storage_class == new_storage_class) {
2396                                                 errorf(declaration->source_position, "redeclaration of '%Y'", symbol);
2397                                         } else {
2398                                                 errorf(declaration->source_position, "redeclaration of '%Y' with different linkage", symbol);
2399                                         }
2400                                         errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
2401                                 }
2402                         }
2403                         return previous_declaration;
2404                 }
2405         } else if (is_function_definition) {
2406                 if (declaration->storage_class != STORAGE_CLASS_STATIC) {
2407                         if (warning.missing_prototypes && !is_sym_main(symbol)) {
2408                                 warningf(declaration->source_position, "no previous prototype for '%#T'", orig_type, symbol);
2409                         } else if (warning.missing_declarations && !is_sym_main(symbol)) {
2410                                 warningf(declaration->source_position, "no previous declaration for '%#T'", orig_type, symbol);
2411                         }
2412                 }
2413         } else if (warning.missing_declarations &&
2414             scope == global_scope &&
2415             !is_type_function(type) && (
2416               declaration->storage_class == STORAGE_CLASS_NONE ||
2417               declaration->storage_class == STORAGE_CLASS_THREAD
2418             )) {
2419                 warningf(declaration->source_position, "no previous declaration for '%#T'", orig_type, symbol);
2420         }
2421
2422         assert(declaration->parent_scope == NULL);
2423         assert(declaration->symbol != NULL);
2424         assert(scope != NULL);
2425
2426         declaration->parent_scope = scope;
2427
2428         environment_push(declaration);
2429         return append_declaration(declaration);
2430 }
2431
2432 static declaration_t *record_declaration(declaration_t *declaration)
2433 {
2434         return internal_record_declaration(declaration, false);
2435 }
2436
2437 static declaration_t *record_function_definition(declaration_t *declaration)
2438 {
2439         return internal_record_declaration(declaration, true);
2440 }
2441
2442 static void parser_error_multiple_definition(declaration_t *declaration,
2443                 const source_position_t source_position)
2444 {
2445         errorf(source_position, "multiple definition of symbol '%Y'",
2446                declaration->symbol);
2447         errorf(declaration->source_position,
2448                "this is the location of the previous definition.");
2449 }
2450
2451 static bool is_declaration_specifier(const token_t *token,
2452                                      bool only_type_specifiers)
2453 {
2454         switch(token->type) {
2455                 TYPE_SPECIFIERS
2456                         return true;
2457                 case T_IDENTIFIER:
2458                         return is_typedef_symbol(token->v.symbol);
2459
2460                 case T___extension__:
2461                 STORAGE_CLASSES
2462                 TYPE_QUALIFIERS
2463                         return !only_type_specifiers;
2464
2465                 default:
2466                         return false;
2467         }
2468 }
2469
2470 static void parse_init_declarator_rest(declaration_t *declaration)
2471 {
2472         eat('=');
2473
2474         type_t *orig_type = declaration->type;
2475         type_t *type      = type = skip_typeref(orig_type);
2476
2477         if(declaration->init.initializer != NULL) {
2478                 parser_error_multiple_definition(declaration, token.source_position);
2479         }
2480
2481         initializer_t *initializer = parse_initializer(type);
2482
2483         /* § 6.7.5 (22)  array initializers for arrays with unknown size determine
2484          * the array type size */
2485         if(is_type_array(type) && initializer != NULL) {
2486                 array_type_t *array_type = &type->array;
2487
2488                 if(array_type->size == NULL) {
2489                         expression_t *cnst = allocate_expression_zero(EXPR_CONST);
2490
2491                         cnst->base.type = type_size_t;
2492
2493                         switch (initializer->kind) {
2494                                 case INITIALIZER_LIST: {
2495                                         cnst->conste.v.int_value = initializer->list.len;
2496                                         break;
2497                                 }
2498
2499                                 case INITIALIZER_STRING: {
2500                                         cnst->conste.v.int_value = initializer->string.string.size;
2501                                         break;
2502                                 }
2503
2504                                 case INITIALIZER_WIDE_STRING: {
2505                                         cnst->conste.v.int_value = initializer->wide_string.string.size;
2506                                         break;
2507                                 }
2508
2509                                 default:
2510                                         panic("invalid initializer type");
2511                         }
2512
2513                         array_type->size = cnst;
2514                 }
2515         }
2516
2517         if(is_type_function(type)) {
2518                 errorf(declaration->source_position,
2519                        "initializers not allowed for function types at declator '%Y' (type '%T')",
2520                        declaration->symbol, orig_type);
2521         } else {
2522                 declaration->init.initializer = initializer;
2523         }
2524 }
2525
2526 /* parse rest of a declaration without any declarator */
2527 static void parse_anonymous_declaration_rest(
2528                 const declaration_specifiers_t *specifiers,
2529                 parsed_declaration_func finished_declaration)
2530 {
2531         eat(';');
2532
2533         declaration_t *const declaration = allocate_declaration_zero();
2534         declaration->type            = specifiers->type;
2535         declaration->storage_class   = specifiers->storage_class;
2536         declaration->source_position = specifiers->source_position;
2537
2538         if (declaration->storage_class != STORAGE_CLASS_NONE) {
2539                 warningf(declaration->source_position, "useless storage class in empty declaration");
2540         }
2541
2542         type_t *type = declaration->type;
2543         switch (type->kind) {
2544                 case TYPE_COMPOUND_STRUCT:
2545                 case TYPE_COMPOUND_UNION: {
2546                         if (type->compound.declaration->symbol == NULL) {
2547                                 warningf(declaration->source_position, "unnamed struct/union that defines no instances");
2548                         }
2549                         break;
2550                 }
2551
2552                 case TYPE_ENUM:
2553                         break;
2554
2555                 default:
2556                         warningf(declaration->source_position, "empty declaration");
2557                         break;
2558         }
2559
2560         finished_declaration(declaration);
2561 }
2562
2563 static void parse_declaration_rest(declaration_t *ndeclaration,
2564                 const declaration_specifiers_t *specifiers,
2565                 parsed_declaration_func finished_declaration)
2566 {
2567         while(true) {
2568                 declaration_t *declaration = finished_declaration(ndeclaration);
2569
2570                 type_t *orig_type = declaration->type;
2571                 type_t *type      = skip_typeref(orig_type);
2572
2573                 if (type->kind != TYPE_FUNCTION &&
2574                     declaration->is_inline &&
2575                     is_type_valid(type)) {
2576                         warningf(declaration->source_position,
2577                                  "variable '%Y' declared 'inline'\n", declaration->symbol);
2578                 }
2579
2580                 if(token.type == '=') {
2581                         parse_init_declarator_rest(declaration);
2582                 }
2583
2584                 if(token.type != ',')
2585                         break;
2586                 eat(',');
2587
2588                 ndeclaration = parse_declarator(specifiers, /*may_be_abstract=*/false);
2589         }
2590         expect_void(';');
2591 }
2592
2593 static declaration_t *finished_kr_declaration(declaration_t *declaration)
2594 {
2595         symbol_t *symbol  = declaration->symbol;
2596         if(symbol == NULL) {
2597                 errorf(HERE, "anonymous declaration not valid as function parameter");
2598                 return declaration;
2599         }
2600         namespace_t namespc = (namespace_t) declaration->namespc;
2601         if(namespc != NAMESPACE_NORMAL) {
2602                 return record_declaration(declaration);
2603         }
2604
2605         declaration_t *previous_declaration = get_declaration(symbol, namespc);
2606         if(previous_declaration == NULL ||
2607                         previous_declaration->parent_scope != scope) {
2608                 errorf(HERE, "expected declaration of a function parameter, found '%Y'",
2609                        symbol);
2610                 return declaration;
2611         }
2612
2613         if(previous_declaration->type == NULL) {
2614                 previous_declaration->type           = declaration->type;
2615                 previous_declaration->storage_class  = declaration->storage_class;
2616                 previous_declaration->parent_scope = scope;
2617                 return previous_declaration;
2618         } else {
2619                 return record_declaration(declaration);
2620         }
2621 }
2622
2623 static void parse_declaration(parsed_declaration_func finished_declaration)
2624 {
2625         declaration_specifiers_t specifiers;
2626         memset(&specifiers, 0, sizeof(specifiers));
2627         parse_declaration_specifiers(&specifiers);
2628
2629         if(token.type == ';') {
2630                 parse_anonymous_declaration_rest(&specifiers, finished_declaration);
2631         } else {
2632                 declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
2633                 parse_declaration_rest(declaration, &specifiers, finished_declaration);
2634         }
2635 }
2636
2637 static void parse_kr_declaration_list(declaration_t *declaration)
2638 {
2639         type_t *type = skip_typeref(declaration->type);
2640         if(!is_type_function(type))
2641                 return;
2642
2643         if(!type->function.kr_style_parameters)
2644                 return;
2645
2646         /* push function parameters */
2647         int       top        = environment_top();
2648         scope_t  *last_scope = scope;
2649         set_scope(&declaration->scope);
2650
2651         declaration_t *parameter = declaration->scope.declarations;
2652         for( ; parameter != NULL; parameter = parameter->next) {
2653                 assert(parameter->parent_scope == NULL);
2654                 parameter->parent_scope = scope;
2655                 environment_push(parameter);
2656         }
2657
2658         /* parse declaration list */
2659         while(is_declaration_specifier(&token, false)) {
2660                 parse_declaration(finished_kr_declaration);
2661         }
2662
2663         /* pop function parameters */
2664         assert(scope == &declaration->scope);
2665         set_scope(last_scope);
2666         environment_pop_to(top);
2667
2668         /* update function type */
2669         type_t *new_type = duplicate_type(type);
2670         new_type->function.kr_style_parameters = false;
2671
2672         function_parameter_t *parameters     = NULL;
2673         function_parameter_t *last_parameter = NULL;
2674
2675         declaration_t *parameter_declaration = declaration->scope.declarations;
2676         for( ; parameter_declaration != NULL;
2677                         parameter_declaration = parameter_declaration->next) {
2678                 type_t *parameter_type = parameter_declaration->type;
2679                 if(parameter_type == NULL) {
2680                         if (strict_mode) {
2681                                 errorf(HERE, "no type specified for function parameter '%Y'",
2682                                        parameter_declaration->symbol);
2683                         } else {
2684                                 if (warning.implicit_int) {
2685                                         warningf(HERE, "no type specified for function parameter '%Y', using 'int'",
2686                                                 parameter_declaration->symbol);
2687                                 }
2688                                 parameter_type              = type_int;
2689                                 parameter_declaration->type = parameter_type;
2690                         }
2691                 }
2692
2693                 semantic_parameter(parameter_declaration);
2694                 parameter_type = parameter_declaration->type;
2695
2696                 function_parameter_t *function_parameter
2697                         = obstack_alloc(type_obst, sizeof(function_parameter[0]));
2698                 memset(function_parameter, 0, sizeof(function_parameter[0]));
2699
2700                 function_parameter->type = parameter_type;
2701                 if(last_parameter != NULL) {
2702                         last_parameter->next = function_parameter;
2703                 } else {
2704                         parameters = function_parameter;
2705                 }
2706                 last_parameter = function_parameter;
2707         }
2708         new_type->function.parameters = parameters;
2709
2710         type = typehash_insert(new_type);
2711         if(type != new_type) {
2712                 obstack_free(type_obst, new_type);
2713         }
2714
2715         declaration->type = type;
2716 }
2717
2718 static bool first_err = true;
2719
2720 /**
2721  * When called with first_err set, prints the name of the current function,
2722  * else does noting.
2723  */
2724 static void print_in_function(void) {
2725         if (first_err) {
2726                 first_err = false;
2727                 diagnosticf("%s: In function '%Y':\n",
2728                         current_function->source_position.input_name,
2729                         current_function->symbol);
2730         }
2731 }
2732
2733 /**
2734  * Check if all labels are defined in the current function.
2735  * Check if all labels are used in the current function.
2736  */
2737 static void check_labels(void)
2738 {
2739         for (const goto_statement_t *goto_statement = goto_first;
2740             goto_statement != NULL;
2741             goto_statement = goto_statement->next) {
2742                 declaration_t *label = goto_statement->label;
2743
2744                 label->used = true;
2745                 if (label->source_position.input_name == NULL) {
2746                         print_in_function();
2747                         errorf(goto_statement->base.source_position,
2748                                "label '%Y' used but not defined", label->symbol);
2749                  }
2750         }
2751         goto_first = goto_last = NULL;
2752
2753         if (warning.unused_label) {
2754                 for (const label_statement_t *label_statement = label_first;
2755                          label_statement != NULL;
2756                          label_statement = label_statement->next) {
2757                         const declaration_t *label = label_statement->label;
2758
2759                         if (! label->used) {
2760                                 print_in_function();
2761                                 warningf(label_statement->base.source_position,
2762                                         "label '%Y' defined but not used", label->symbol);
2763                         }
2764                 }
2765         }
2766         label_first = label_last = NULL;
2767 }
2768
2769 /**
2770  * Check declarations of current_function for unused entities.
2771  */
2772 static void check_declarations(void)
2773 {
2774         if (warning.unused_parameter) {
2775                 const scope_t *scope = &current_function->scope;
2776
2777                 const declaration_t *parameter = scope->declarations;
2778                 for (; parameter != NULL; parameter = parameter->next) {
2779                         if (! parameter->used) {
2780                                 print_in_function();
2781                                 warningf(parameter->source_position,
2782                                         "unused parameter '%Y'", parameter->symbol);
2783                         }
2784                 }
2785         }
2786         if (warning.unused_variable) {
2787         }
2788 }
2789
2790 static void parse_external_declaration(void)
2791 {
2792         /* function-definitions and declarations both start with declaration
2793          * specifiers */
2794         declaration_specifiers_t specifiers;
2795         memset(&specifiers, 0, sizeof(specifiers));
2796         parse_declaration_specifiers(&specifiers);
2797
2798         /* must be a declaration */
2799         if(token.type == ';') {
2800                 parse_anonymous_declaration_rest(&specifiers, append_declaration);
2801                 return;
2802         }
2803
2804         /* declarator is common to both function-definitions and declarations */
2805         declaration_t *ndeclaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
2806
2807         /* must be a declaration */
2808         if(token.type == ',' || token.type == '=' || token.type == ';') {
2809                 parse_declaration_rest(ndeclaration, &specifiers, record_declaration);
2810                 return;
2811         }
2812
2813         /* must be a function definition */
2814         parse_kr_declaration_list(ndeclaration);
2815
2816         if(token.type != '{') {
2817                 parse_error_expected("while parsing function definition", '{', 0);
2818                 eat_statement();
2819                 return;
2820         }
2821
2822         type_t *type = ndeclaration->type;
2823
2824         /* note that we don't skip typerefs: the standard doesn't allow them here
2825          * (so we can't use is_type_function here) */
2826         if(type->kind != TYPE_FUNCTION) {
2827                 if (is_type_valid(type)) {
2828                         errorf(HERE, "declarator '%#T' has a body but is not a function type",
2829                                type, ndeclaration->symbol);
2830                 }
2831                 eat_block();
2832                 return;
2833         }
2834
2835         /* § 6.7.5.3 (14) a function definition with () means no
2836          * parameters (and not unspecified parameters) */
2837         if(type->function.unspecified_parameters) {
2838                 type_t *duplicate = duplicate_type(type);
2839                 duplicate->function.unspecified_parameters = false;
2840
2841                 type = typehash_insert(duplicate);
2842                 if(type != duplicate) {
2843                         obstack_free(type_obst, duplicate);
2844                 }
2845                 ndeclaration->type = type;
2846         }
2847
2848         declaration_t *const declaration = record_function_definition(ndeclaration);
2849         if(ndeclaration != declaration) {
2850                 declaration->scope = ndeclaration->scope;
2851         }
2852         type = skip_typeref(declaration->type);
2853
2854         /* push function parameters and switch scope */
2855         int       top        = environment_top();
2856         scope_t  *last_scope = scope;
2857         set_scope(&declaration->scope);
2858
2859         declaration_t *parameter = declaration->scope.declarations;
2860         for( ; parameter != NULL; parameter = parameter->next) {
2861                 if(parameter->parent_scope == &ndeclaration->scope) {
2862                         parameter->parent_scope = scope;
2863                 }
2864                 assert(parameter->parent_scope == NULL
2865                                 || parameter->parent_scope == scope);
2866                 parameter->parent_scope = scope;
2867                 environment_push(parameter);
2868         }
2869
2870         if(declaration->init.statement != NULL) {
2871                 parser_error_multiple_definition(declaration, token.source_position);
2872                 eat_block();
2873                 goto end_of_parse_external_declaration;
2874         } else {
2875                 /* parse function body */
2876                 int            label_stack_top      = label_top();
2877                 declaration_t *old_current_function = current_function;
2878                 current_function                    = declaration;
2879
2880                 declaration->init.statement = parse_compound_statement();
2881                 first_err = true;
2882                 check_labels();
2883                 check_declarations();
2884
2885                 assert(current_function == declaration);
2886                 current_function = old_current_function;
2887                 label_pop_to(label_stack_top);
2888         }
2889
2890 end_of_parse_external_declaration:
2891         assert(scope == &declaration->scope);
2892         set_scope(last_scope);
2893         environment_pop_to(top);
2894 }
2895
2896 static type_t *make_bitfield_type(type_t *base, expression_t *size)
2897 {
2898         type_t *type        = allocate_type_zero(TYPE_BITFIELD);
2899         type->bitfield.base = base;
2900         type->bitfield.size = size;
2901
2902         return type;
2903 }
2904
2905 static void parse_struct_declarators(const declaration_specifiers_t *specifiers)
2906 {
2907         /* TODO: check constraints for struct declarations (in specifiers) */
2908         while(1) {
2909                 declaration_t *declaration;
2910
2911                 if(token.type == ':') {
2912                         next_token();
2913
2914                         type_t *base_type = specifiers->type;
2915                         expression_t *size = parse_constant_expression();
2916
2917                         type_t *type = make_bitfield_type(base_type, size);
2918
2919                         declaration = allocate_declaration_zero();
2920                         declaration->namespc         = NAMESPACE_NORMAL;
2921                         declaration->storage_class   = STORAGE_CLASS_NONE;
2922                         declaration->source_position = token.source_position;
2923                         declaration->modifiers       = specifiers->decl_modifiers;
2924                         declaration->type            = type;
2925                 } else {
2926                         declaration = parse_declarator(specifiers,/*may_be_abstract=*/true);
2927
2928                         if(token.type == ':') {
2929                                 next_token();
2930                                 expression_t *size = parse_constant_expression();
2931
2932                                 type_t *type = make_bitfield_type(declaration->type, size);
2933                                 declaration->type = type;
2934                         }
2935                 }
2936                 record_declaration(declaration);
2937
2938                 if(token.type != ',')
2939                         break;
2940                 next_token();
2941         }
2942         expect_void(';');
2943 }
2944
2945 static void parse_compound_type_entries(void)
2946 {
2947         eat('{');
2948
2949         while(token.type != '}' && token.type != T_EOF) {
2950                 declaration_specifiers_t specifiers;
2951                 memset(&specifiers, 0, sizeof(specifiers));
2952                 parse_declaration_specifiers(&specifiers);
2953
2954                 parse_struct_declarators(&specifiers);
2955         }
2956         if(token.type == T_EOF) {
2957                 errorf(HERE, "EOF while parsing struct");
2958         }
2959         next_token();
2960 }
2961
2962 static type_t *parse_typename(void)
2963 {
2964         declaration_specifiers_t specifiers;
2965         memset(&specifiers, 0, sizeof(specifiers));
2966         parse_declaration_specifiers(&specifiers);
2967         if(specifiers.storage_class != STORAGE_CLASS_NONE) {
2968                 /* TODO: improve error message, user does probably not know what a
2969                  * storage class is...
2970                  */
2971                 errorf(HERE, "typename may not have a storage class");
2972         }
2973
2974         type_t *result = parse_abstract_declarator(specifiers.type);
2975
2976         return result;
2977 }
2978
2979
2980
2981
2982 typedef expression_t* (*parse_expression_function) (unsigned precedence);
2983 typedef expression_t* (*parse_expression_infix_function) (unsigned precedence,
2984                                                           expression_t *left);
2985
2986 typedef struct expression_parser_function_t expression_parser_function_t;
2987 struct expression_parser_function_t {
2988         unsigned                         precedence;
2989         parse_expression_function        parser;
2990         unsigned                         infix_precedence;
2991         parse_expression_infix_function  infix_parser;
2992 };
2993
2994 expression_parser_function_t expression_parsers[T_LAST_TOKEN];
2995
2996 /**
2997  * Creates a new invalid expression.
2998  */
2999 static expression_t *create_invalid_expression(void)
3000 {
3001         expression_t *expression         = allocate_expression_zero(EXPR_INVALID);
3002         expression->base.source_position = token.source_position;
3003         return expression;
3004 }
3005
3006 /**
3007  * Prints an error message if an expression was expected but not read
3008  */
3009 static expression_t *expected_expression_error(void)
3010 {
3011         /* skip the error message if the error token was read */
3012         if (token.type != T_ERROR) {
3013                 errorf(HERE, "expected expression, got token '%K'", &token);
3014         }
3015         next_token();
3016
3017         return create_invalid_expression();
3018 }
3019
3020 /**
3021  * Parse a string constant.
3022  */
3023 static expression_t *parse_string_const(void)
3024 {
3025         expression_t *cnst = allocate_expression_zero(EXPR_STRING_LITERAL);
3026         cnst->base.type    = type_char_ptr;
3027         cnst->string.value = parse_string_literals();
3028
3029         return cnst;
3030 }
3031
3032 /**
3033  * Parse a wide string constant.
3034  */
3035 static expression_t *parse_wide_string_const(void)
3036 {
3037         expression_t *const cnst = allocate_expression_zero(EXPR_WIDE_STRING_LITERAL);
3038         cnst->base.type         = type_wchar_t_ptr;
3039         cnst->wide_string.value = token.v.wide_string; /* TODO concatenate */
3040         next_token();
3041         return cnst;
3042 }
3043
3044 /**
3045  * Parse an integer constant.
3046  */
3047 static expression_t *parse_int_const(void)
3048 {
3049         expression_t *cnst       = allocate_expression_zero(EXPR_CONST);
3050         cnst->base.type          = token.datatype;
3051         cnst->conste.v.int_value = token.v.intvalue;
3052
3053         next_token();
3054
3055         return cnst;
3056 }
3057
3058 /**
3059  * Parse a float constant.
3060  */
3061 static expression_t *parse_float_const(void)
3062 {
3063         expression_t *cnst         = allocate_expression_zero(EXPR_CONST);
3064         cnst->base.type            = token.datatype;
3065         cnst->conste.v.float_value = token.v.floatvalue;
3066
3067         next_token();
3068
3069         return cnst;
3070 }
3071
3072 static declaration_t *create_implicit_function(symbol_t *symbol,
3073                 const source_position_t source_position)
3074 {
3075         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
3076         ntype->function.return_type            = type_int;
3077         ntype->function.unspecified_parameters = true;
3078
3079         type_t *type = typehash_insert(ntype);
3080         if(type != ntype) {
3081                 free_type(ntype);
3082         }
3083
3084         declaration_t *const declaration = allocate_declaration_zero();
3085         declaration->storage_class   = STORAGE_CLASS_EXTERN;
3086         declaration->type            = type;
3087         declaration->symbol          = symbol;
3088         declaration->source_position = source_position;
3089         declaration->parent_scope  = global_scope;
3090
3091         scope_t *old_scope = scope;
3092         set_scope(global_scope);
3093
3094         environment_push(declaration);
3095         /* prepends the declaration to the global declarations list */
3096         declaration->next   = scope->declarations;
3097         scope->declarations = declaration;
3098
3099         assert(scope == global_scope);
3100         set_scope(old_scope);
3101
3102         return declaration;
3103 }
3104
3105 /**
3106  * Creates a return_type (func)(argument_type) function type if not
3107  * already exists.
3108  *
3109  * @param return_type    the return type
3110  * @param argument_type  the argument type
3111  */
3112 static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
3113 {
3114         function_parameter_t *parameter
3115                 = obstack_alloc(type_obst, sizeof(parameter[0]));
3116         memset(parameter, 0, sizeof(parameter[0]));
3117         parameter->type = argument_type;
3118
3119         type_t *type               = allocate_type_zero(TYPE_FUNCTION);
3120         type->function.return_type = return_type;
3121         type->function.parameters  = parameter;
3122
3123         type_t *result = typehash_insert(type);
3124         if(result != type) {
3125                 free_type(type);
3126         }
3127
3128         return result;
3129 }
3130
3131 /**
3132  * Creates a function type for some function like builtins.
3133  *
3134  * @param symbol   the symbol describing the builtin
3135  */
3136 static type_t *get_builtin_symbol_type(symbol_t *symbol)
3137 {
3138         switch(symbol->ID) {
3139         case T___builtin_alloca:
3140                 return make_function_1_type(type_void_ptr, type_size_t);
3141         case T___builtin_nan:
3142                 return make_function_1_type(type_double, type_char_ptr);
3143         case T___builtin_nanf:
3144                 return make_function_1_type(type_float, type_char_ptr);
3145         case T___builtin_nand:
3146                 return make_function_1_type(type_long_double, type_char_ptr);
3147         case T___builtin_va_end:
3148                 return make_function_1_type(type_void, type_valist);
3149         default:
3150                 panic("not implemented builtin symbol found");
3151         }
3152 }
3153
3154 /**
3155  * Performs automatic type cast as described in § 6.3.2.1.
3156  *
3157  * @param orig_type  the original type
3158  */
3159 static type_t *automatic_type_conversion(type_t *orig_type)
3160 {
3161         type_t *type = skip_typeref(orig_type);
3162         if(is_type_array(type)) {
3163                 array_type_t *array_type   = &type->array;
3164                 type_t       *element_type = array_type->element_type;
3165                 unsigned      qualifiers   = array_type->type.qualifiers;
3166
3167                 return make_pointer_type(element_type, qualifiers);
3168         }
3169
3170         if(is_type_function(type)) {
3171                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
3172         }
3173
3174         return orig_type;
3175 }
3176
3177 /**
3178  * reverts the automatic casts of array to pointer types and function
3179  * to function-pointer types as defined § 6.3.2.1
3180  */
3181 type_t *revert_automatic_type_conversion(const expression_t *expression)
3182 {
3183         switch (expression->kind) {
3184                 case EXPR_REFERENCE: return expression->reference.declaration->type;
3185                 case EXPR_SELECT:    return expression->select.compound_entry->type;
3186
3187                 case EXPR_UNARY_DEREFERENCE: {
3188                         const expression_t *const value = expression->unary.value;
3189                         type_t             *const type  = skip_typeref(value->base.type);
3190                         assert(is_type_pointer(type));
3191                         return type->pointer.points_to;
3192                 }
3193
3194                 case EXPR_BUILTIN_SYMBOL:
3195                         return get_builtin_symbol_type(expression->builtin_symbol.symbol);
3196
3197                 case EXPR_ARRAY_ACCESS: {
3198                         const expression_t *array_ref = expression->array_access.array_ref;
3199                         type_t             *type_left = skip_typeref(array_ref->base.type);
3200                         if (!is_type_valid(type_left))
3201                                 return type_left;
3202                         assert(is_type_pointer(type_left));
3203                         return type_left->pointer.points_to;
3204                 }
3205
3206                 default: break;
3207         }
3208
3209         return expression->base.type;
3210 }
3211
3212 static expression_t *parse_reference(void)
3213 {
3214         expression_t *expression = allocate_expression_zero(EXPR_REFERENCE);
3215
3216         reference_expression_t *ref = &expression->reference;
3217         ref->symbol = token.v.symbol;
3218
3219         declaration_t *declaration = get_declaration(ref->symbol, NAMESPACE_NORMAL);
3220
3221         source_position_t source_position = token.source_position;
3222         next_token();
3223
3224         if(declaration == NULL) {
3225                 if (! strict_mode && token.type == '(') {
3226                         /* an implicitly defined function */
3227                         if (warning.implicit_function_declaration) {
3228                                 warningf(HERE, "implicit declaration of function '%Y'",
3229                                         ref->symbol);
3230                         }
3231
3232                         declaration = create_implicit_function(ref->symbol,
3233                                                                source_position);
3234                 } else {
3235                         errorf(HERE, "unknown symbol '%Y' found.", ref->symbol);
3236                         return expression;
3237                 }
3238         }
3239
3240         type_t *type         = declaration->type;
3241
3242         /* we always do the auto-type conversions; the & and sizeof parser contains
3243          * code to revert this! */
3244         type = automatic_type_conversion(type);
3245
3246         ref->declaration = declaration;
3247         ref->base.type   = type;
3248
3249         /* this declaration is used */
3250         declaration->used = true;
3251
3252         return expression;
3253 }
3254
3255 static void check_cast_allowed(expression_t *expression, type_t *dest_type)
3256 {
3257         (void) expression;
3258         (void) dest_type;
3259         /* TODO check if explicit cast is allowed and issue warnings/errors */
3260 }
3261
3262 static expression_t *parse_cast(void)
3263 {
3264         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
3265
3266         cast->base.source_position = token.source_position;
3267
3268         type_t *type  = parse_typename();
3269
3270         expect(')');
3271         expression_t *value = parse_sub_expression(20);
3272
3273         check_cast_allowed(value, type);
3274
3275         cast->base.type   = type;
3276         cast->unary.value = value;
3277
3278         return cast;
3279 }
3280
3281 static expression_t *parse_statement_expression(void)
3282 {
3283         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
3284
3285         statement_t *statement           = parse_compound_statement();
3286         expression->statement.statement  = statement;
3287         expression->base.source_position = statement->base.source_position;
3288
3289         /* find last statement and use its type */
3290         type_t *type = type_void;
3291         const statement_t *stmt = statement->compound.statements;
3292         if (stmt != NULL) {
3293                 while (stmt->base.next != NULL)
3294                         stmt = stmt->base.next;
3295
3296                 if (stmt->kind == STATEMENT_EXPRESSION) {
3297                         type = stmt->expression.expression->base.type;
3298                 }
3299         } else {
3300                 warningf(expression->base.source_position, "empty statement expression ({})");
3301         }
3302         expression->base.type = type;
3303
3304         expect(')');
3305
3306         return expression;
3307 }
3308
3309 static expression_t *parse_brace_expression(void)
3310 {
3311         eat('(');
3312
3313         switch(token.type) {
3314         case '{':
3315                 /* gcc extension: a statement expression */
3316                 return parse_statement_expression();
3317
3318         TYPE_QUALIFIERS
3319         TYPE_SPECIFIERS
3320                 return parse_cast();
3321         case T_IDENTIFIER:
3322                 if(is_typedef_symbol(token.v.symbol)) {
3323                         return parse_cast();
3324                 }
3325         }
3326
3327         expression_t *result = parse_expression();
3328         expect(')');
3329
3330         return result;
3331 }
3332
3333 static expression_t *parse_function_keyword(void)
3334 {
3335         next_token();
3336         /* TODO */
3337
3338         if (current_function == NULL) {
3339                 errorf(HERE, "'__func__' used outside of a function");
3340         }
3341
3342         expression_t *expression = allocate_expression_zero(EXPR_FUNCTION);
3343         expression->base.type    = type_char_ptr;
3344
3345         return expression;
3346 }
3347
3348 static expression_t *parse_pretty_function_keyword(void)
3349 {
3350         eat(T___PRETTY_FUNCTION__);
3351         /* TODO */
3352
3353         if (current_function == NULL) {
3354                 errorf(HERE, "'__PRETTY_FUNCTION__' used outside of a function");
3355         }
3356
3357         expression_t *expression = allocate_expression_zero(EXPR_PRETTY_FUNCTION);
3358         expression->base.type    = type_char_ptr;
3359
3360         return expression;
3361 }
3362
3363 static designator_t *parse_designator(void)
3364 {
3365         designator_t *result = allocate_ast_zero(sizeof(result[0]));
3366
3367         if(token.type != T_IDENTIFIER) {
3368                 parse_error_expected("while parsing member designator",
3369                                      T_IDENTIFIER, 0);
3370                 eat_paren();
3371                 return NULL;
3372         }
3373         result->symbol = token.v.symbol;
3374         next_token();
3375
3376         designator_t *last_designator = result;
3377         while(true) {
3378                 if(token.type == '.') {
3379                         next_token();
3380                         if(token.type != T_IDENTIFIER) {
3381                                 parse_error_expected("while parsing member designator",
3382                                                      T_IDENTIFIER, 0);
3383                                 eat_paren();
3384                                 return NULL;
3385                         }
3386                         designator_t *designator = allocate_ast_zero(sizeof(result[0]));
3387                         designator->symbol       = token.v.symbol;
3388                         next_token();
3389
3390                         last_designator->next = designator;
3391                         last_designator       = designator;
3392                         continue;
3393                 }
3394                 if(token.type == '[') {
3395                         next_token();
3396                         designator_t *designator = allocate_ast_zero(sizeof(result[0]));
3397                         designator->array_access = parse_expression();
3398                         if(designator->array_access == NULL) {
3399                                 eat_paren();
3400                                 return NULL;
3401                         }
3402                         expect(']');
3403
3404                         last_designator->next = designator;
3405                         last_designator       = designator;
3406                         continue;
3407                 }
3408                 break;
3409         }
3410
3411         return result;
3412 }
3413
3414 static expression_t *parse_offsetof(void)
3415 {
3416         eat(T___builtin_offsetof);
3417
3418         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
3419         expression->base.type    = type_size_t;
3420
3421         expect('(');
3422         expression->offsetofe.type = parse_typename();
3423         expect(',');
3424         expression->offsetofe.designator = parse_designator();
3425         expect(')');
3426
3427         return expression;
3428 }
3429
3430 static expression_t *parse_va_start(void)
3431 {
3432         eat(T___builtin_va_start);
3433
3434         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
3435
3436         expect('(');
3437         expression->va_starte.ap = parse_assignment_expression();
3438         expect(',');
3439         expression_t *const expr = parse_assignment_expression();
3440         if (expr->kind == EXPR_REFERENCE) {
3441                 declaration_t *const decl = expr->reference.declaration;
3442                 if (decl == NULL)
3443                         return create_invalid_expression();
3444                 if (decl->parent_scope == &current_function->scope &&
3445                     decl->next == NULL) {
3446                         expression->va_starte.parameter = decl;
3447                         expect(')');
3448                         return expression;
3449                 }
3450         }
3451         errorf(expr->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
3452
3453         return create_invalid_expression();
3454 }
3455
3456 static expression_t *parse_va_arg(void)
3457 {
3458         eat(T___builtin_va_arg);
3459
3460         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
3461
3462         expect('(');
3463         expression->va_arge.ap = parse_assignment_expression();
3464         expect(',');
3465         expression->base.type = parse_typename();
3466         expect(')');
3467
3468         return expression;
3469 }
3470
3471 static expression_t *parse_builtin_symbol(void)
3472 {
3473         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_SYMBOL);
3474
3475         symbol_t *symbol = token.v.symbol;
3476
3477         expression->builtin_symbol.symbol = symbol;
3478         next_token();
3479
3480         type_t *type = get_builtin_symbol_type(symbol);
3481         type = automatic_type_conversion(type);
3482
3483         expression->base.type = type;
3484         return expression;
3485 }
3486
3487 static expression_t *parse_builtin_constant(void)
3488 {
3489         eat(T___builtin_constant_p);
3490
3491         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
3492
3493         expect('(');
3494         expression->builtin_constant.value = parse_assignment_expression();
3495         expect(')');
3496         expression->base.type = type_int;
3497
3498         return expression;
3499 }
3500
3501 static expression_t *parse_builtin_prefetch(void)
3502 {
3503         eat(T___builtin_prefetch);
3504
3505         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_PREFETCH);
3506
3507         expect('(');
3508         expression->builtin_prefetch.adr = parse_assignment_expression();
3509         if (token.type == ',') {
3510                 next_token();
3511                 expression->builtin_prefetch.rw = parse_assignment_expression();
3512         }
3513         if (token.type == ',') {
3514                 next_token();
3515                 expression->builtin_prefetch.locality = parse_assignment_expression();
3516         }
3517         expect(')');
3518         expression->base.type = type_void;
3519
3520         return expression;
3521 }
3522
3523 static expression_t *parse_compare_builtin(void)
3524 {
3525         expression_t *expression;
3526
3527         switch(token.type) {
3528         case T___builtin_isgreater:
3529                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATER);
3530                 break;
3531         case T___builtin_isgreaterequal:
3532                 expression = allocate_expression_zero(EXPR_BINARY_ISGREATEREQUAL);
3533                 break;
3534         case T___builtin_isless:
3535                 expression = allocate_expression_zero(EXPR_BINARY_ISLESS);
3536                 break;
3537         case T___builtin_islessequal:
3538                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSEQUAL);
3539                 break;
3540         case T___builtin_islessgreater:
3541                 expression = allocate_expression_zero(EXPR_BINARY_ISLESSGREATER);
3542                 break;
3543         case T___builtin_isunordered:
3544                 expression = allocate_expression_zero(EXPR_BINARY_ISUNORDERED);
3545                 break;
3546         default:
3547                 panic("invalid compare builtin found");
3548                 break;
3549         }
3550         expression->base.source_position = HERE;
3551         next_token();
3552
3553         expect('(');
3554         expression->binary.left = parse_assignment_expression();
3555         expect(',');
3556         expression->binary.right = parse_assignment_expression();
3557         expect(')');
3558
3559         type_t *const orig_type_left  = expression->binary.left->base.type;
3560         type_t *const orig_type_right = expression->binary.right->base.type;
3561
3562         type_t *const type_left  = skip_typeref(orig_type_left);
3563         type_t *const type_right = skip_typeref(orig_type_right);
3564         if(!is_type_float(type_left) && !is_type_float(type_right)) {
3565                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
3566                         type_error_incompatible("invalid operands in comparison",
3567                                 expression->base.source_position, orig_type_left, orig_type_right);
3568                 }
3569         } else {
3570                 semantic_comparison(&expression->binary);
3571         }
3572
3573         return expression;
3574 }
3575
3576 static expression_t *parse_builtin_expect(void)
3577 {
3578         eat(T___builtin_expect);
3579
3580         expression_t *expression
3581                 = allocate_expression_zero(EXPR_BINARY_BUILTIN_EXPECT);
3582
3583         expect('(');
3584         expression->binary.left = parse_assignment_expression();
3585         expect(',');
3586         expression->binary.right = parse_constant_expression();
3587         expect(')');
3588
3589         expression->base.type = expression->binary.left->base.type;
3590
3591         return expression;
3592 }
3593
3594 static expression_t *parse_assume(void) {
3595         eat(T_assume);
3596
3597         expression_t *expression
3598                 = allocate_expression_zero(EXPR_UNARY_ASSUME);
3599
3600         expect('(');
3601         expression->unary.value = parse_assignment_expression();
3602         expect(')');
3603
3604         expression->base.type = type_void;
3605         return expression;
3606 }
3607
3608 static expression_t *parse_primary_expression(void)
3609 {
3610         switch(token.type) {
3611         case T_INTEGER:
3612                 return parse_int_const();
3613         case T_FLOATINGPOINT:
3614                 return parse_float_const();
3615         case T_STRING_LITERAL:
3616                 return parse_string_const();
3617         case T_WIDE_STRING_LITERAL:
3618                 return parse_wide_string_const();
3619         case T_IDENTIFIER:
3620                 return parse_reference();
3621         case T___FUNCTION__:
3622         case T___func__:
3623                 return parse_function_keyword();
3624         case T___PRETTY_FUNCTION__:
3625                 return parse_pretty_function_keyword();
3626         case T___builtin_offsetof:
3627                 return parse_offsetof();
3628         case T___builtin_va_start:
3629                 return parse_va_start();
3630         case T___builtin_va_arg:
3631                 return parse_va_arg();
3632         case T___builtin_expect:
3633                 return parse_builtin_expect();
3634         case T___builtin_nanf:
3635         case T___builtin_alloca:
3636         case T___builtin_va_end:
3637                 return parse_builtin_symbol();
3638         case T___builtin_isgreater:
3639         case T___builtin_isgreaterequal:
3640         case T___builtin_isless:
3641         case T___builtin_islessequal:
3642         case T___builtin_islessgreater:
3643         case T___builtin_isunordered:
3644                 return parse_compare_builtin();
3645         case T___builtin_constant_p:
3646                 return parse_builtin_constant();
3647         case T___builtin_prefetch:
3648                 return parse_builtin_prefetch();
3649         case T_assume:
3650                 return parse_assume();
3651
3652         case '(':
3653                 return parse_brace_expression();
3654         }
3655
3656         errorf(HERE, "unexpected token '%K'", &token);
3657         eat_statement();
3658
3659         return create_invalid_expression();
3660 }
3661
3662 /**
3663  * Check if the expression has the character type and issue a warning then.
3664  */
3665 static void check_for_char_index_type(const expression_t *expression) {
3666         type_t       *const type      = expression->base.type;
3667         const type_t *const base_type = skip_typeref(type);
3668
3669         if (is_type_atomic(base_type, ATOMIC_TYPE_CHAR) &&
3670                         warning.char_subscripts) {
3671                 warningf(expression->base.source_position,
3672                         "array subscript has type '%T'", type);
3673         }
3674 }
3675
3676 static expression_t *parse_array_expression(unsigned precedence,
3677                                             expression_t *left)
3678 {
3679         (void) precedence;
3680
3681         eat('[');
3682
3683         expression_t *inside = parse_expression();
3684
3685         expression_t *expression = allocate_expression_zero(EXPR_ARRAY_ACCESS);
3686
3687         array_access_expression_t *array_access = &expression->array_access;
3688
3689         type_t *const orig_type_left   = left->base.type;
3690         type_t *const orig_type_inside = inside->base.type;
3691
3692         type_t *const type_left   = skip_typeref(orig_type_left);
3693         type_t *const type_inside = skip_typeref(orig_type_inside);
3694
3695         type_t *return_type;
3696         if (is_type_pointer(type_left)) {
3697                 return_type             = type_left->pointer.points_to;
3698                 array_access->array_ref = left;
3699                 array_access->index     = inside;
3700                 check_for_char_index_type(inside);
3701         } else if (is_type_pointer(type_inside)) {
3702                 return_type             = type_inside->pointer.points_to;
3703                 array_access->array_ref = inside;
3704                 array_access->index     = left;
3705                 array_access->flipped   = true;
3706                 check_for_char_index_type(left);
3707         } else {
3708                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
3709                         errorf(HERE,
3710                                 "array access on object with non-pointer types '%T', '%T'",
3711                                 orig_type_left, orig_type_inside);
3712                 }
3713                 return_type             = type_error_type;
3714                 array_access->array_ref = create_invalid_expression();
3715         }
3716
3717         if(token.type != ']') {
3718                 parse_error_expected("Problem while parsing array access", ']', 0);
3719                 return expression;
3720         }
3721         next_token();
3722
3723         return_type           = automatic_type_conversion(return_type);
3724         expression->base.type = return_type;
3725
3726         return expression;
3727 }
3728
3729 static expression_t *parse_typeprop(expression_kind_t kind, unsigned precedence)
3730 {
3731         expression_t *tp_expression = allocate_expression_zero(kind);
3732         tp_expression->base.type    = type_size_t;
3733
3734         if(token.type == '(' && is_declaration_specifier(look_ahead(1), true)) {
3735                 next_token();
3736                 tp_expression->typeprop.type = parse_typename();
3737                 expect(')');
3738         } else {
3739                 expression_t *expression = parse_sub_expression(precedence);
3740                 expression->base.type    = revert_automatic_type_conversion(expression);
3741
3742                 tp_expression->typeprop.type          = expression->base.type;
3743                 tp_expression->typeprop.tp_expression = expression;
3744         }
3745
3746         return tp_expression;
3747 }
3748
3749 static expression_t *parse_sizeof(unsigned precedence)
3750 {
3751         eat(T_sizeof);
3752         return parse_typeprop(EXPR_SIZEOF, precedence);
3753 }
3754
3755 static expression_t *parse_alignof(unsigned precedence)
3756 {
3757         eat(T___alignof__);
3758         return parse_typeprop(EXPR_SIZEOF, precedence);
3759 }
3760
3761 static expression_t *parse_select_expression(unsigned precedence,
3762                                              expression_t *compound)
3763 {
3764         (void) precedence;
3765         assert(token.type == '.' || token.type == T_MINUSGREATER);
3766
3767         bool is_pointer = (token.type == T_MINUSGREATER);
3768         next_token();
3769
3770         expression_t *select    = allocate_expression_zero(EXPR_SELECT);
3771         select->select.compound = compound;
3772
3773         if(token.type != T_IDENTIFIER) {
3774                 parse_error_expected("while parsing select", T_IDENTIFIER, 0);
3775                 return select;
3776         }
3777         symbol_t *symbol      = token.v.symbol;
3778         select->select.symbol = symbol;
3779         next_token();
3780
3781         type_t *const orig_type = compound->base.type;
3782         type_t *const type      = skip_typeref(orig_type);
3783
3784         type_t *type_left = type;
3785         if(is_pointer) {
3786                 if (!is_type_pointer(type)) {
3787                         if (is_type_valid(type)) {
3788                                 errorf(HERE, "left hand side of '->' is not a pointer, but '%T'", orig_type);
3789                         }
3790                         return create_invalid_expression();
3791                 }
3792                 type_left = type->pointer.points_to;
3793         }
3794         type_left = skip_typeref(type_left);
3795
3796         if (type_left->kind != TYPE_COMPOUND_STRUCT &&
3797             type_left->kind != TYPE_COMPOUND_UNION) {
3798                 if (is_type_valid(type_left)) {
3799                         errorf(HERE, "request for member '%Y' in something not a struct or "
3800                                "union, but '%T'", symbol, type_left);
3801                 }
3802                 return create_invalid_expression();
3803         }
3804
3805         declaration_t *const declaration = type_left->compound.declaration;
3806
3807         if(!declaration->init.is_defined) {
3808                 errorf(HERE, "request for member '%Y' of incomplete type '%T'",
3809                        symbol, type_left);
3810                 return create_invalid_expression();
3811         }
3812
3813         declaration_t *iter = declaration->scope.declarations;
3814         for( ; iter != NULL; iter = iter->next) {
3815                 if(iter->symbol == symbol) {
3816                         break;
3817                 }
3818         }
3819         if(iter == NULL) {
3820                 errorf(HERE, "'%T' has no member named '%Y'", orig_type, symbol);
3821                 return create_invalid_expression();
3822         }
3823
3824         /* we always do the auto-type conversions; the & and sizeof parser contains
3825          * code to revert this! */
3826         type_t *expression_type = automatic_type_conversion(iter->type);
3827
3828         select->select.compound_entry = iter;
3829         select->base.type             = expression_type;
3830
3831         if(expression_type->kind == TYPE_BITFIELD) {
3832                 expression_t *extract
3833                         = allocate_expression_zero(EXPR_UNARY_BITFIELD_EXTRACT);
3834                 extract->unary.value = select;
3835                 extract->base.type   = expression_type->bitfield.base;
3836
3837                 return extract;
3838         }
3839
3840         return select;
3841 }
3842
3843 /**
3844  * Parse a call expression, ie. expression '( ... )'.
3845  *
3846  * @param expression  the function address
3847  */
3848 static expression_t *parse_call_expression(unsigned precedence,
3849                                            expression_t *expression)
3850 {
3851         (void) precedence;
3852         expression_t *result = allocate_expression_zero(EXPR_CALL);
3853
3854         call_expression_t *call = &result->call;
3855         call->function          = expression;
3856
3857         type_t *const orig_type = expression->base.type;
3858         type_t *const type      = skip_typeref(orig_type);
3859
3860         function_type_t *function_type = NULL;
3861         if (is_type_pointer(type)) {
3862                 type_t *const to_type = skip_typeref(type->pointer.points_to);
3863
3864                 if (is_type_function(to_type)) {
3865                         function_type   = &to_type->function;
3866                         call->base.type = function_type->return_type;
3867                 }
3868         }
3869
3870         if (function_type == NULL && is_type_valid(type)) {
3871                 errorf(HERE, "called object '%E' (type '%T') is not a pointer to a function", expression, orig_type);
3872         }
3873
3874         /* parse arguments */
3875         eat('(');
3876
3877         if(token.type != ')') {
3878                 call_argument_t *last_argument = NULL;
3879
3880                 while(true) {
3881                         call_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
3882
3883                         argument->expression = parse_assignment_expression();
3884                         if(last_argument == NULL) {
3885                                 call->arguments = argument;
3886                         } else {
3887                                 last_argument->next = argument;
3888                         }
3889                         last_argument = argument;
3890
3891                         if(token.type != ',')
3892                                 break;
3893                         next_token();
3894                 }
3895         }
3896         expect(')');
3897
3898         if(function_type != NULL) {
3899                 function_parameter_t *parameter = function_type->parameters;
3900                 call_argument_t      *argument  = call->arguments;
3901                 for( ; parameter != NULL && argument != NULL;
3902                                 parameter = parameter->next, argument = argument->next) {
3903                         type_t *expected_type = parameter->type;
3904                         /* TODO report scope in error messages */
3905                         expression_t *const arg_expr = argument->expression;
3906                         type_t       *const res_type = semantic_assign(expected_type, arg_expr, "function call");
3907                         if (res_type == NULL) {
3908                                 /* TODO improve error message */
3909                                 errorf(arg_expr->base.source_position,
3910                                         "Cannot call function with argument '%E' of type '%T' where type '%T' is expected",
3911                                         arg_expr, arg_expr->base.type, expected_type);
3912                         } else {
3913                                 argument->expression = create_implicit_cast(argument->expression, expected_type);
3914                         }
3915                 }
3916                 /* too few parameters */
3917                 if(parameter != NULL) {
3918                         errorf(HERE, "too few arguments to function '%E'", expression);
3919                 } else if(argument != NULL) {
3920                         /* too many parameters */
3921                         if(!function_type->variadic
3922                                         && !function_type->unspecified_parameters) {
3923                                 errorf(HERE, "too many arguments to function '%E'", expression);
3924                         } else {
3925                                 /* do default promotion */
3926                                 for( ; argument != NULL; argument = argument->next) {
3927                                         type_t *type = argument->expression->base.type;
3928
3929                                         type = skip_typeref(type);
3930                                         if(is_type_integer(type)) {
3931                                                 type = promote_integer(type);
3932                                         } else if(type == type_float) {
3933                                                 type = type_double;
3934                                         }
3935
3936                                         argument->expression
3937                                                 = create_implicit_cast(argument->expression, type);
3938                                 }
3939
3940                                 check_format(&result->call);
3941                         }
3942                 } else {
3943                         check_format(&result->call);
3944                 }
3945         }
3946
3947         return result;
3948 }
3949
3950 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
3951
3952 static bool same_compound_type(const type_t *type1, const type_t *type2)
3953 {
3954         return
3955                 is_type_compound(type1) &&
3956                 type1->kind == type2->kind &&
3957                 type1->compound.declaration == type2->compound.declaration;
3958 }
3959
3960 /**
3961  * Parse a conditional expression, ie. 'expression ? ... : ...'.
3962  *
3963  * @param expression  the conditional expression
3964  */
3965 static expression_t *parse_conditional_expression(unsigned precedence,
3966                                                   expression_t *expression)
3967 {
3968         eat('?');
3969
3970         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
3971
3972         conditional_expression_t *conditional = &result->conditional;
3973         conditional->condition = expression;
3974
3975         /* 6.5.15.2 */
3976         type_t *const condition_type_orig = expression->base.type;
3977         type_t *const condition_type      = skip_typeref(condition_type_orig);
3978         if (!is_type_scalar(condition_type) && is_type_valid(condition_type)) {
3979                 type_error("expected a scalar type in conditional condition",
3980                            expression->base.source_position, condition_type_orig);
3981         }
3982
3983         expression_t *true_expression = parse_expression();
3984         expect(':');
3985         expression_t *false_expression = parse_sub_expression(precedence);
3986
3987         conditional->true_expression  = true_expression;
3988         conditional->false_expression = false_expression;
3989
3990         type_t *const orig_true_type  = true_expression->base.type;
3991         type_t *const orig_false_type = false_expression->base.type;
3992         type_t *const true_type       = skip_typeref(orig_true_type);
3993         type_t *const false_type      = skip_typeref(orig_false_type);
3994
3995         /* 6.5.15.3 */
3996         type_t *result_type;
3997         if (is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
3998                 result_type = semantic_arithmetic(true_type, false_type);
3999
4000                 true_expression  = create_implicit_cast(true_expression, result_type);
4001                 false_expression = create_implicit_cast(false_expression, result_type);
4002
4003                 conditional->true_expression  = true_expression;
4004                 conditional->false_expression = false_expression;
4005                 conditional->base.type        = result_type;
4006         } else if (same_compound_type(true_type, false_type) || (
4007             is_type_atomic(true_type, ATOMIC_TYPE_VOID) &&
4008             is_type_atomic(false_type, ATOMIC_TYPE_VOID)
4009                 )) {
4010                 /* just take 1 of the 2 types */
4011                 result_type = true_type;
4012         } else if (is_type_pointer(true_type) && is_type_pointer(false_type)
4013                         && pointers_compatible(true_type, false_type)) {
4014                 /* ok */
4015                 result_type = true_type;
4016         } else {
4017                 /* TODO */
4018                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
4019                         type_error_incompatible("while parsing conditional",
4020                                                 expression->base.source_position, true_type,
4021                                                 false_type);
4022                 }
4023                 result_type = type_error_type;
4024         }
4025
4026         conditional->base.type = result_type;
4027         return result;
4028 }
4029
4030 /**
4031  * Parse an extension expression.
4032  */
4033 static expression_t *parse_extension(unsigned precedence)
4034 {
4035         eat(T___extension__);
4036
4037         /* TODO enable extensions */
4038         expression_t *expression = parse_sub_expression(precedence);
4039         /* TODO disable extensions */
4040         return expression;
4041 }
4042
4043 static expression_t *parse_builtin_classify_type(const unsigned precedence)
4044 {
4045         eat(T___builtin_classify_type);
4046
4047         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
4048         result->base.type    = type_int;
4049
4050         expect('(');
4051         expression_t *expression = parse_sub_expression(precedence);
4052         expect(')');
4053         result->classify_type.type_expression = expression;
4054
4055         return result;
4056 }
4057
4058 static void semantic_incdec(unary_expression_t *expression)
4059 {
4060         type_t *const orig_type = expression->value->base.type;
4061         type_t *const type      = skip_typeref(orig_type);
4062         /* TODO !is_type_real && !is_type_pointer */
4063         if(!is_type_arithmetic(type) && type->kind != TYPE_POINTER) {
4064                 if (is_type_valid(type)) {
4065                         /* TODO: improve error message */
4066                         errorf(HERE, "operation needs an arithmetic or pointer type");
4067                 }
4068                 return;
4069         }
4070
4071         expression->base.type = orig_type;
4072 }
4073
4074 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
4075 {
4076         type_t *const orig_type = expression->value->base.type;
4077         type_t *const type      = skip_typeref(orig_type);
4078         if(!is_type_arithmetic(type)) {
4079                 if (is_type_valid(type)) {
4080                         /* TODO: improve error message */
4081                         errorf(HERE, "operation needs an arithmetic type");
4082                 }
4083                 return;
4084         }
4085
4086         expression->base.type = orig_type;
4087 }
4088
4089 static void semantic_unexpr_scalar(unary_expression_t *expression)
4090 {
4091         type_t *const orig_type = expression->value->base.type;
4092         type_t *const type      = skip_typeref(orig_type);
4093         if (!is_type_scalar(type)) {
4094                 if (is_type_valid(type)) {
4095                         errorf(HERE, "operand of ! must be of scalar type");
4096                 }
4097                 return;
4098         }
4099
4100         expression->base.type = orig_type;
4101 }
4102
4103 static void semantic_unexpr_integer(unary_expression_t *expression)
4104 {
4105         type_t *const orig_type = expression->value->base.type;
4106         type_t *const type      = skip_typeref(orig_type);
4107         if (!is_type_integer(type)) {
4108                 if (is_type_valid(type)) {
4109                         errorf(HERE, "operand of ~ must be of integer type");
4110                 }
4111                 return;
4112         }
4113
4114         expression->base.type = orig_type;
4115 }
4116
4117 static void semantic_dereference(unary_expression_t *expression)
4118 {
4119         type_t *const orig_type = expression->value->base.type;
4120         type_t *const type      = skip_typeref(orig_type);
4121         if(!is_type_pointer(type)) {
4122                 if (is_type_valid(type)) {
4123                         errorf(HERE, "Unary '*' needs pointer or arrray type, but type '%T' given", orig_type);
4124                 }
4125                 return;
4126         }
4127
4128         type_t *result_type   = type->pointer.points_to;
4129         result_type           = automatic_type_conversion(result_type);
4130         expression->base.type = result_type;
4131 }
4132
4133 /**
4134  * Check the semantic of the address taken expression.
4135  */
4136 static void semantic_take_addr(unary_expression_t *expression)
4137 {
4138         expression_t *value = expression->value;
4139         value->base.type    = revert_automatic_type_conversion(value);
4140
4141         type_t *orig_type = value->base.type;
4142         if(!is_type_valid(orig_type))
4143                 return;
4144
4145         if(value->kind == EXPR_REFERENCE) {
4146                 declaration_t *const declaration = value->reference.declaration;
4147                 if(declaration != NULL) {
4148                         if (declaration->storage_class == STORAGE_CLASS_REGISTER) {
4149                                 errorf(expression->base.source_position,
4150                                         "address of register variable '%Y' requested",
4151                                         declaration->symbol);
4152                         }
4153                         declaration->address_taken = 1;
4154                 }
4155         }
4156
4157         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
4158 }
4159
4160 #define CREATE_UNARY_EXPRESSION_PARSER(token_type, unexpression_type, sfunc)   \
4161 static expression_t *parse_##unexpression_type(unsigned precedence)            \
4162 {                                                                              \
4163         eat(token_type);                                                           \
4164                                                                                    \
4165         expression_t *unary_expression                                             \
4166                 = allocate_expression_zero(unexpression_type);                         \
4167         unary_expression->base.source_position = HERE;                             \
4168         unary_expression->unary.value = parse_sub_expression(precedence);          \
4169                                                                                    \
4170         sfunc(&unary_expression->unary);                                           \
4171                                                                                    \
4172         return unary_expression;                                                   \
4173 }
4174
4175 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
4176                                semantic_unexpr_arithmetic)
4177 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
4178                                semantic_unexpr_arithmetic)
4179 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
4180                                semantic_unexpr_scalar)
4181 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
4182                                semantic_dereference)
4183 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
4184                                semantic_take_addr)
4185 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
4186                                semantic_unexpr_integer)
4187 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
4188                                semantic_incdec)
4189 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
4190                                semantic_incdec)
4191
4192 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_type, unexpression_type, \
4193                                                sfunc)                         \
4194 static expression_t *parse_##unexpression_type(unsigned precedence,           \
4195                                                expression_t *left)            \
4196 {                                                                             \
4197         (void) precedence;                                                        \
4198         eat(token_type);                                                          \
4199                                                                               \
4200         expression_t *unary_expression                                            \
4201                 = allocate_expression_zero(unexpression_type);                        \
4202         unary_expression->unary.value = left;                                     \
4203                                                                                   \
4204         sfunc(&unary_expression->unary);                                          \
4205                                                                               \
4206         return unary_expression;                                                  \
4207 }
4208
4209 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
4210                                        EXPR_UNARY_POSTFIX_INCREMENT,
4211                                        semantic_incdec)
4212 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
4213                                        EXPR_UNARY_POSTFIX_DECREMENT,
4214                                        semantic_incdec)
4215
4216 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
4217 {
4218         /* TODO: handle complex + imaginary types */
4219
4220         /* § 6.3.1.8 Usual arithmetic conversions */
4221         if(type_left == type_long_double || type_right == type_long_double) {
4222                 return type_long_double;
4223         } else if(type_left == type_double || type_right == type_double) {
4224                 return type_double;
4225         } else if(type_left == type_float || type_right == type_float) {
4226                 return type_float;
4227         }
4228
4229         type_right = promote_integer(type_right);
4230         type_left  = promote_integer(type_left);
4231
4232         if(type_left == type_right)
4233                 return type_left;
4234
4235         bool signed_left  = is_type_signed(type_left);
4236         bool signed_right = is_type_signed(type_right);
4237         int  rank_left    = get_rank(type_left);
4238         int  rank_right   = get_rank(type_right);
4239         if(rank_left < rank_right) {
4240                 if(signed_left == signed_right || !signed_right) {
4241                         return type_right;
4242                 } else {
4243                         return type_left;
4244                 }
4245         } else {
4246                 if(signed_left == signed_right || !signed_left) {
4247                         return type_left;
4248                 } else {
4249                         return type_right;
4250                 }
4251         }
4252 }
4253
4254 /**
4255  * Check the semantic restrictions for a binary expression.
4256  */
4257 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
4258 {
4259         expression_t *const left            = expression->left;
4260         expression_t *const right           = expression->right;
4261         type_t       *const orig_type_left  = left->base.type;
4262         type_t       *const orig_type_right = right->base.type;
4263         type_t       *const type_left       = skip_typeref(orig_type_left);
4264         type_t       *const type_right      = skip_typeref(orig_type_right);
4265
4266         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4267                 /* TODO: improve error message */
4268                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4269                         errorf(HERE, "operation needs arithmetic types");
4270                 }
4271                 return;
4272         }
4273
4274         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4275         expression->left      = create_implicit_cast(left, arithmetic_type);
4276         expression->right     = create_implicit_cast(right, arithmetic_type);
4277         expression->base.type = arithmetic_type;
4278 }
4279
4280 static void semantic_shift_op(binary_expression_t *expression)
4281 {
4282         expression_t *const left            = expression->left;
4283         expression_t *const right           = expression->right;
4284         type_t       *const orig_type_left  = left->base.type;
4285         type_t       *const orig_type_right = right->base.type;
4286         type_t       *      type_left       = skip_typeref(orig_type_left);
4287         type_t       *      type_right      = skip_typeref(orig_type_right);
4288
4289         if(!is_type_integer(type_left) || !is_type_integer(type_right)) {
4290                 /* TODO: improve error message */
4291                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4292                         errorf(HERE, "operation needs integer types");
4293                 }
4294                 return;
4295         }
4296
4297         type_left  = promote_integer(type_left);
4298         type_right = promote_integer(type_right);
4299
4300         expression->left      = create_implicit_cast(left, type_left);
4301         expression->right     = create_implicit_cast(right, type_right);
4302         expression->base.type = type_left;
4303 }
4304
4305 static void semantic_add(binary_expression_t *expression)
4306 {
4307         expression_t *const left            = expression->left;
4308         expression_t *const right           = expression->right;
4309         type_t       *const orig_type_left  = left->base.type;
4310         type_t       *const orig_type_right = right->base.type;
4311         type_t       *const type_left       = skip_typeref(orig_type_left);
4312         type_t       *const type_right      = skip_typeref(orig_type_right);
4313
4314         /* § 5.6.5 */
4315         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4316                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4317                 expression->left  = create_implicit_cast(left, arithmetic_type);
4318                 expression->right = create_implicit_cast(right, arithmetic_type);
4319                 expression->base.type = arithmetic_type;
4320                 return;
4321         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4322                 expression->base.type = type_left;
4323         } else if(is_type_pointer(type_right) && is_type_integer(type_left)) {
4324                 expression->base.type = type_right;
4325         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4326                 errorf(HERE, "invalid operands to binary + ('%T', '%T')", orig_type_left, orig_type_right);
4327         }
4328 }
4329
4330 static void semantic_sub(binary_expression_t *expression)
4331 {
4332         expression_t *const left            = expression->left;
4333         expression_t *const right           = expression->right;
4334         type_t       *const orig_type_left  = left->base.type;
4335         type_t       *const orig_type_right = right->base.type;
4336         type_t       *const type_left       = skip_typeref(orig_type_left);
4337         type_t       *const type_right      = skip_typeref(orig_type_right);
4338
4339         /* § 5.6.5 */
4340         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4341                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4342                 expression->left        = create_implicit_cast(left, arithmetic_type);
4343                 expression->right       = create_implicit_cast(right, arithmetic_type);
4344                 expression->base.type =  arithmetic_type;
4345                 return;
4346         } else if(is_type_pointer(type_left) && is_type_integer(type_right)) {
4347                 expression->base.type = type_left;
4348         } else if(is_type_pointer(type_left) && is_type_pointer(type_right)) {
4349                 if(!pointers_compatible(type_left, type_right)) {
4350                         errorf(HERE,
4351                                "pointers to incompatible objects to binary '-' ('%T', '%T')",
4352                                orig_type_left, orig_type_right);
4353                 } else {
4354                         expression->base.type = type_ptrdiff_t;
4355                 }
4356         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4357                 errorf(HERE, "invalid operands to binary '-' ('%T', '%T')",
4358                        orig_type_left, orig_type_right);
4359         }
4360 }
4361
4362 /**
4363  * Check the semantics of comparison expressions.
4364  *
4365  * @param expression   The expression to check.
4366  */
4367 static void semantic_comparison(binary_expression_t *expression)
4368 {
4369         expression_t *left            = expression->left;
4370         expression_t *right           = expression->right;
4371         type_t       *orig_type_left  = left->base.type;
4372         type_t       *orig_type_right = right->base.type;
4373
4374         type_t *type_left  = skip_typeref(orig_type_left);
4375         type_t *type_right = skip_typeref(orig_type_right);
4376
4377         /* TODO non-arithmetic types */
4378         if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4379                 if (warning.sign_compare &&
4380                     (expression->base.kind != EXPR_BINARY_EQUAL &&
4381                      expression->base.kind != EXPR_BINARY_NOTEQUAL) &&
4382                     (is_type_signed(type_left) != is_type_signed(type_right))) {
4383                         warningf(expression->base.source_position,
4384                                  "comparison between signed and unsigned");
4385                 }
4386                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4387                 expression->left        = create_implicit_cast(left, arithmetic_type);
4388                 expression->right       = create_implicit_cast(right, arithmetic_type);
4389                 expression->base.type   = arithmetic_type;
4390                 if (warning.float_equal &&
4391                     (expression->base.kind == EXPR_BINARY_EQUAL ||
4392                      expression->base.kind == EXPR_BINARY_NOTEQUAL) &&
4393                     is_type_float(arithmetic_type)) {
4394                         warningf(expression->base.source_position,
4395                                  "comparing floating point with == or != is unsafe");
4396                 }
4397         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
4398                 /* TODO check compatibility */
4399         } else if (is_type_pointer(type_left)) {
4400                 expression->right = create_implicit_cast(right, type_left);
4401         } else if (is_type_pointer(type_right)) {
4402                 expression->left = create_implicit_cast(left, type_right);
4403         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4404                 type_error_incompatible("invalid operands in comparison",
4405                                         expression->base.source_position,
4406                                         type_left, type_right);
4407         }
4408         expression->base.type = type_int;
4409 }
4410
4411 static void semantic_arithmetic_assign(binary_expression_t *expression)
4412 {
4413         expression_t *left            = expression->left;
4414         expression_t *right           = expression->right;
4415         type_t       *orig_type_left  = left->base.type;
4416         type_t       *orig_type_right = right->base.type;
4417
4418         type_t *type_left  = skip_typeref(orig_type_left);
4419         type_t *type_right = skip_typeref(orig_type_right);
4420
4421         if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
4422                 /* TODO: improve error message */
4423                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4424                         errorf(HERE, "operation needs arithmetic types");
4425                 }
4426                 return;
4427         }
4428
4429         /* combined instructions are tricky. We can't create an implicit cast on
4430          * the left side, because we need the uncasted form for the store.
4431          * The ast2firm pass has to know that left_type must be right_type
4432          * for the arithmetic operation and create a cast by itself */
4433         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
4434         expression->right       = create_implicit_cast(right, arithmetic_type);
4435         expression->base.type   = type_left;
4436 }
4437
4438 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
4439 {
4440         expression_t *const left            = expression->left;
4441         expression_t *const right           = expression->right;
4442         type_t       *const orig_type_left  = left->base.type;
4443         type_t       *const orig_type_right = right->base.type;
4444         type_t       *const type_left       = skip_typeref(orig_type_left);
4445         type_t       *const type_right      = skip_typeref(orig_type_right);
4446
4447         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
4448                 /* combined instructions are tricky. We can't create an implicit cast on
4449                  * the left side, because we need the uncasted form for the store.
4450                  * The ast2firm pass has to know that left_type must be right_type
4451                  * for the arithmetic operation and create a cast by itself */
4452                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
4453                 expression->right     = create_implicit_cast(right, arithmetic_type);
4454                 expression->base.type = type_left;
4455         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
4456                 expression->base.type = type_left;
4457         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
4458                 errorf(HERE, "incompatible types '%T' and '%T' in assignment", orig_type_left, orig_type_right);
4459         }
4460 }
4461
4462 /**
4463  * Check the semantic restrictions of a logical expression.
4464  */
4465 static void semantic_logical_op(binary_expression_t *expression)
4466 {
4467         expression_t *const left            = expression->left;
4468         expression_t *const right           = expression->right;
4469         type_t       *const orig_type_left  = left->base.type;
4470         type_t       *const orig_type_right = right->base.type;
4471         type_t       *const type_left       = skip_typeref(orig_type_left);
4472         type_t       *const type_right      = skip_typeref(orig_type_right);
4473
4474         if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
4475                 /* TODO: improve error message */
4476                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
4477                         errorf(HERE, "operation needs scalar types");
4478                 }
4479                 return;
4480         }
4481
4482         expression->base.type = type_int;
4483 }
4484
4485 /**
4486  * Checks if a compound type has constant fields.
4487  */
4488 static bool has_const_fields(const compound_type_t *type)
4489 {
4490         const scope_t       *scope       = &type->declaration->scope;
4491         const declaration_t *declaration = scope->declarations;
4492
4493         for (; declaration != NULL; declaration = declaration->next) {
4494                 if (declaration->namespc != NAMESPACE_NORMAL)
4495                         continue;
4496
4497                 const type_t *decl_type = skip_typeref(declaration->type);
4498                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
4499                         return true;
4500         }
4501         /* TODO */
4502         return false;
4503 }
4504
4505 /**
4506  * Check the semantic restrictions of a binary assign expression.
4507  */
4508 static void semantic_binexpr_assign(binary_expression_t *expression)
4509 {
4510         expression_t *left           = expression->left;
4511         type_t       *orig_type_left = left->base.type;
4512
4513         type_t *type_left = revert_automatic_type_conversion(left);
4514         type_left         = skip_typeref(orig_type_left);
4515
4516         /* must be a modifiable lvalue */
4517         if (is_type_array(type_left)) {
4518                 errorf(HERE, "cannot assign to arrays ('%E')", left);
4519                 return;
4520         }
4521         if(type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
4522                 errorf(HERE, "assignment to readonly location '%E' (type '%T')", left,
4523                        orig_type_left);
4524                 return;
4525         }
4526         if(is_type_incomplete(type_left)) {
4527                 errorf(HERE,
4528                        "left-hand side of assignment '%E' has incomplete type '%T'",
4529                        left, orig_type_left);
4530                 return;
4531         }
4532         if(is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
4533                 errorf(HERE, "cannot assign to '%E' because compound type '%T' has readonly fields",
4534                        left, orig_type_left);
4535                 return;
4536         }
4537
4538         type_t *const res_type = semantic_assign(orig_type_left, expression->right,
4539                                                  "assignment");
4540         if (res_type == NULL) {
4541                 errorf(expression->base.source_position,
4542                         "cannot assign to '%T' from '%T'",
4543                         orig_type_left, expression->right->base.type);
4544         } else {
4545                 expression->right = create_implicit_cast(expression->right, res_type);
4546         }
4547
4548         expression->base.type = orig_type_left;
4549 }
4550
4551 static bool expression_has_effect(const expression_t *const expr)
4552 {
4553         switch (expr->kind) {
4554                 case EXPR_UNKNOWN:                   break;
4555                 case EXPR_INVALID:                   break;
4556                 case EXPR_REFERENCE:                 return false;
4557                 case EXPR_CONST:                     return false;
4558                 case EXPR_STRING_LITERAL:            return false;
4559                 case EXPR_WIDE_STRING_LITERAL:       return false;
4560                 case EXPR_CALL: {
4561                         const call_expression_t *const call = &expr->call;
4562                         if (call->function->kind != EXPR_BUILTIN_SYMBOL)
4563                                 return true;
4564
4565                         switch (call->function->builtin_symbol.symbol->ID) {
4566                                 case T___builtin_va_end: return true;
4567                                 default:                 return false;
4568                         }
4569                 }
4570                 case EXPR_CONDITIONAL: {
4571                         const conditional_expression_t *const cond = &expr->conditional;
4572                         return
4573                                 expression_has_effect(cond->true_expression) &&
4574                                 expression_has_effect(cond->false_expression);
4575                 }
4576                 case EXPR_SELECT:                    return false;
4577                 case EXPR_ARRAY_ACCESS:              return false;
4578                 case EXPR_SIZEOF:                    return false;
4579                 case EXPR_CLASSIFY_TYPE:             return false;
4580                 case EXPR_ALIGNOF:                   return false;
4581
4582                 case EXPR_FUNCTION:                  return false;
4583                 case EXPR_PRETTY_FUNCTION:           return false;
4584                 case EXPR_BUILTIN_SYMBOL:            break; /* handled in EXPR_CALL */
4585                 case EXPR_BUILTIN_CONSTANT_P:        return false;
4586                 case EXPR_BUILTIN_PREFETCH:          return true;
4587                 case EXPR_OFFSETOF:                  return false;
4588                 case EXPR_VA_START:                  return true;
4589                 case EXPR_VA_ARG:                    return true;
4590                 case EXPR_STATEMENT:                 return true; // TODO
4591
4592                 case EXPR_UNARY_NEGATE:              return false;
4593                 case EXPR_UNARY_PLUS:                return false;
4594                 case EXPR_UNARY_BITWISE_NEGATE:      return false;
4595                 case EXPR_UNARY_NOT:                 return false;
4596                 case EXPR_UNARY_DEREFERENCE:         return false;
4597                 case EXPR_UNARY_TAKE_ADDRESS:        return false;
4598                 case EXPR_UNARY_POSTFIX_INCREMENT:   return true;
4599                 case EXPR_UNARY_POSTFIX_DECREMENT:   return true;
4600                 case EXPR_UNARY_PREFIX_INCREMENT:    return true;
4601                 case EXPR_UNARY_PREFIX_DECREMENT:    return true;
4602                 case EXPR_UNARY_CAST:
4603                         return is_type_atomic(expr->base.type, ATOMIC_TYPE_VOID);
4604                 case EXPR_UNARY_CAST_IMPLICIT:       return true;
4605                 case EXPR_UNARY_ASSUME:              return true;
4606                 case EXPR_UNARY_BITFIELD_EXTRACT:    return false;
4607
4608                 case EXPR_BINARY_ADD:                return false;
4609                 case EXPR_BINARY_SUB:                return false;
4610                 case EXPR_BINARY_MUL:                return false;
4611                 case EXPR_BINARY_DIV:                return false;
4612                 case EXPR_BINARY_MOD:                return false;
4613                 case EXPR_BINARY_EQUAL:              return false;
4614                 case EXPR_BINARY_NOTEQUAL:           return false;
4615                 case EXPR_BINARY_LESS:               return false;
4616                 case EXPR_BINARY_LESSEQUAL:          return false;
4617                 case EXPR_BINARY_GREATER:            return false;
4618                 case EXPR_BINARY_GREATEREQUAL:       return false;
4619                 case EXPR_BINARY_BITWISE_AND:        return false;
4620                 case EXPR_BINARY_BITWISE_OR:         return false;
4621                 case EXPR_BINARY_BITWISE_XOR:        return false;
4622                 case EXPR_BINARY_SHIFTLEFT:          return false;
4623                 case EXPR_BINARY_SHIFTRIGHT:         return false;
4624                 case EXPR_BINARY_ASSIGN:             return true;
4625                 case EXPR_BINARY_MUL_ASSIGN:         return true;
4626                 case EXPR_BINARY_DIV_ASSIGN:         return true;
4627                 case EXPR_BINARY_MOD_ASSIGN:         return true;
4628                 case EXPR_BINARY_ADD_ASSIGN:         return true;
4629                 case EXPR_BINARY_SUB_ASSIGN:         return true;
4630                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:   return true;
4631                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:  return true;
4632                 case EXPR_BINARY_BITWISE_AND_ASSIGN: return true;
4633                 case EXPR_BINARY_BITWISE_XOR_ASSIGN: return true;
4634                 case EXPR_BINARY_BITWISE_OR_ASSIGN:  return true;
4635                 case EXPR_BINARY_LOGICAL_AND:
4636                 case EXPR_BINARY_LOGICAL_OR:
4637                 case EXPR_BINARY_COMMA:
4638                         return expression_has_effect(expr->binary.right);
4639
4640                 case EXPR_BINARY_BUILTIN_EXPECT:     return true;
4641                 case EXPR_BINARY_ISGREATER:          return false;
4642                 case EXPR_BINARY_ISGREATEREQUAL:     return false;
4643                 case EXPR_BINARY_ISLESS:             return false;
4644                 case EXPR_BINARY_ISLESSEQUAL:        return false;
4645                 case EXPR_BINARY_ISLESSGREATER:      return false;
4646                 case EXPR_BINARY_ISUNORDERED:        return false;
4647         }
4648
4649         panic("unexpected statement");
4650 }
4651
4652 static void semantic_comma(binary_expression_t *expression)
4653 {
4654         if (warning.unused_value) {
4655                 const expression_t *const left = expression->left;
4656                 if (!expression_has_effect(left)) {
4657                         warningf(left->base.source_position, "left-hand operand of comma expression has no effect");
4658                 }
4659         }
4660         expression->base.type = expression->right->base.type;
4661 }
4662
4663 #define CREATE_BINEXPR_PARSER(token_type, binexpression_type, sfunc, lr)  \
4664 static expression_t *parse_##binexpression_type(unsigned precedence,      \
4665                                                 expression_t *left)       \
4666 {                                                                         \
4667         eat(token_type);                                                      \
4668         source_position_t pos = HERE;                                         \
4669                                                                           \
4670         expression_t *right = parse_sub_expression(precedence + lr);          \
4671                                                                           \
4672         expression_t *binexpr = allocate_expression_zero(binexpression_type); \
4673         binexpr->base.source_position = pos;                                  \
4674         binexpr->binary.left  = left;                                         \
4675         binexpr->binary.right = right;                                        \
4676         sfunc(&binexpr->binary);                                              \
4677                                                                           \
4678         return binexpr;                                                       \
4679 }
4680
4681 CREATE_BINEXPR_PARSER(',', EXPR_BINARY_COMMA,    semantic_comma, 1)
4682 CREATE_BINEXPR_PARSER('*', EXPR_BINARY_MUL,      semantic_binexpr_arithmetic, 1)
4683 CREATE_BINEXPR_PARSER('/', EXPR_BINARY_DIV,      semantic_binexpr_arithmetic, 1)
4684 CREATE_BINEXPR_PARSER('%', EXPR_BINARY_MOD,      semantic_binexpr_arithmetic, 1)
4685 CREATE_BINEXPR_PARSER('+', EXPR_BINARY_ADD,      semantic_add, 1)
4686 CREATE_BINEXPR_PARSER('-', EXPR_BINARY_SUB,      semantic_sub, 1)
4687 CREATE_BINEXPR_PARSER('<', EXPR_BINARY_LESS,     semantic_comparison, 1)
4688 CREATE_BINEXPR_PARSER('>', EXPR_BINARY_GREATER,  semantic_comparison, 1)
4689 CREATE_BINEXPR_PARSER('=', EXPR_BINARY_ASSIGN,   semantic_binexpr_assign, 0)
4690
4691 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,
4692                       semantic_comparison, 1)
4693 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,
4694                       semantic_comparison, 1)
4695 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,
4696                       semantic_comparison, 1)
4697 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,
4698                       semantic_comparison, 1)
4699
4700 CREATE_BINEXPR_PARSER('&', EXPR_BINARY_BITWISE_AND,
4701                       semantic_binexpr_arithmetic, 1)
4702 CREATE_BINEXPR_PARSER('|', EXPR_BINARY_BITWISE_OR,
4703                       semantic_binexpr_arithmetic, 1)
4704 CREATE_BINEXPR_PARSER('^', EXPR_BINARY_BITWISE_XOR,
4705                       semantic_binexpr_arithmetic, 1)
4706 CREATE_BINEXPR_PARSER(T_ANDAND, EXPR_BINARY_LOGICAL_AND,
4707                       semantic_logical_op, 1)
4708 CREATE_BINEXPR_PARSER(T_PIPEPIPE, EXPR_BINARY_LOGICAL_OR,
4709                       semantic_logical_op, 1)
4710 CREATE_BINEXPR_PARSER(T_LESSLESS, EXPR_BINARY_SHIFTLEFT,
4711                       semantic_shift_op, 1)
4712 CREATE_BINEXPR_PARSER(T_GREATERGREATER, EXPR_BINARY_SHIFTRIGHT,
4713                       semantic_shift_op, 1)
4714 CREATE_BINEXPR_PARSER(T_PLUSEQUAL, EXPR_BINARY_ADD_ASSIGN,
4715                       semantic_arithmetic_addsubb_assign, 0)
4716 CREATE_BINEXPR_PARSER(T_MINUSEQUAL, EXPR_BINARY_SUB_ASSIGN,
4717                       semantic_arithmetic_addsubb_assign, 0)
4718 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL, EXPR_BINARY_MUL_ASSIGN,
4719                       semantic_arithmetic_assign, 0)
4720 CREATE_BINEXPR_PARSER(T_SLASHEQUAL, EXPR_BINARY_DIV_ASSIGN,
4721                       semantic_arithmetic_assign, 0)
4722 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL, EXPR_BINARY_MOD_ASSIGN,
4723                       semantic_arithmetic_assign, 0)
4724 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL, EXPR_BINARY_SHIFTLEFT_ASSIGN,
4725                       semantic_arithmetic_assign, 0)
4726 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL, EXPR_BINARY_SHIFTRIGHT_ASSIGN,
4727                       semantic_arithmetic_assign, 0)
4728 CREATE_BINEXPR_PARSER(T_ANDEQUAL, EXPR_BINARY_BITWISE_AND_ASSIGN,
4729                       semantic_arithmetic_assign, 0)
4730 CREATE_BINEXPR_PARSER(T_PIPEEQUAL, EXPR_BINARY_BITWISE_OR_ASSIGN,
4731                       semantic_arithmetic_assign, 0)
4732 CREATE_BINEXPR_PARSER(T_CARETEQUAL, EXPR_BINARY_BITWISE_XOR_ASSIGN,
4733                       semantic_arithmetic_assign, 0)
4734
4735 static expression_t *parse_sub_expression(unsigned precedence)
4736 {
4737         if(token.type < 0) {
4738                 return expected_expression_error();
4739         }
4740
4741         expression_parser_function_t *parser
4742                 = &expression_parsers[token.type];
4743         source_position_t             source_position = token.source_position;
4744         expression_t                 *left;
4745
4746         if(parser->parser != NULL) {
4747                 left = parser->parser(parser->precedence);
4748         } else {
4749                 left = parse_primary_expression();
4750         }
4751         assert(left != NULL);
4752         left->base.source_position = source_position;
4753
4754         while(true) {
4755                 if(token.type < 0) {
4756                         return expected_expression_error();
4757                 }
4758
4759                 parser = &expression_parsers[token.type];
4760                 if(parser->infix_parser == NULL)
4761                         break;
4762                 if(parser->infix_precedence < precedence)
4763                         break;
4764
4765                 left = parser->infix_parser(parser->infix_precedence, left);
4766
4767                 assert(left != NULL);
4768                 assert(left->kind != EXPR_UNKNOWN);
4769                 left->base.source_position = source_position;
4770         }
4771
4772         return left;
4773 }
4774
4775 /**
4776  * Parse an expression.
4777  */
4778 static expression_t *parse_expression(void)
4779 {
4780         return parse_sub_expression(1);
4781 }
4782
4783 /**
4784  * Register a parser for a prefix-like operator with given precedence.
4785  *
4786  * @param parser      the parser function
4787  * @param token_type  the token type of the prefix token
4788  * @param precedence  the precedence of the operator
4789  */
4790 static void register_expression_parser(parse_expression_function parser,
4791                                        int token_type, unsigned precedence)
4792 {
4793         expression_parser_function_t *entry = &expression_parsers[token_type];
4794
4795         if(entry->parser != NULL) {
4796                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
4797                 panic("trying to register multiple expression parsers for a token");
4798         }
4799         entry->parser     = parser;
4800         entry->precedence = precedence;
4801 }
4802
4803 /**
4804  * Register a parser for an infix operator with given precedence.
4805  *
4806  * @param parser      the parser function
4807  * @param token_type  the token type of the infix operator
4808  * @param precedence  the precedence of the operator
4809  */
4810 static void register_infix_parser(parse_expression_infix_function parser,
4811                 int token_type, unsigned precedence)
4812 {
4813         expression_parser_function_t *entry = &expression_parsers[token_type];
4814
4815         if(entry->infix_parser != NULL) {
4816                 diagnosticf("for token '%k'\n", (token_type_t)token_type);
4817                 panic("trying to register multiple infix expression parsers for a "
4818                       "token");
4819         }
4820         entry->infix_parser     = parser;
4821         entry->infix_precedence = precedence;
4822 }
4823
4824 /**
4825  * Initialize the expression parsers.
4826  */
4827 static void init_expression_parsers(void)
4828 {
4829         memset(&expression_parsers, 0, sizeof(expression_parsers));
4830
4831         register_infix_parser(parse_array_expression,         '[',              30);
4832         register_infix_parser(parse_call_expression,          '(',              30);
4833         register_infix_parser(parse_select_expression,        '.',              30);
4834         register_infix_parser(parse_select_expression,        T_MINUSGREATER,   30);
4835         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,
4836                                                               T_PLUSPLUS,       30);
4837         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,
4838                                                               T_MINUSMINUS,     30);
4839
4840         register_infix_parser(parse_EXPR_BINARY_MUL,          '*',              16);
4841         register_infix_parser(parse_EXPR_BINARY_DIV,          '/',              16);
4842         register_infix_parser(parse_EXPR_BINARY_MOD,          '%',              16);
4843         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,    T_LESSLESS,       16);
4844         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,   T_GREATERGREATER, 16);
4845         register_infix_parser(parse_EXPR_BINARY_ADD,          '+',              15);
4846         register_infix_parser(parse_EXPR_BINARY_SUB,          '-',              15);
4847         register_infix_parser(parse_EXPR_BINARY_LESS,         '<',              14);
4848         register_infix_parser(parse_EXPR_BINARY_GREATER,      '>',              14);
4849         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,    T_LESSEQUAL,      14);
4850         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL, T_GREATEREQUAL,   14);
4851         register_infix_parser(parse_EXPR_BINARY_EQUAL,        T_EQUALEQUAL,     13);
4852         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,
4853                                                     T_EXCLAMATIONMARKEQUAL, 13);
4854         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,  '&',              12);
4855         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,  '^',              11);
4856         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,   '|',              10);
4857         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,  T_ANDAND,          9);
4858         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,   T_PIPEPIPE,        8);
4859         register_infix_parser(parse_conditional_expression,   '?',               7);
4860         register_infix_parser(parse_EXPR_BINARY_ASSIGN,       '=',               2);
4861         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,   T_PLUSEQUAL,       2);
4862         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,   T_MINUSEQUAL,      2);
4863         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,   T_ASTERISKEQUAL,   2);
4864         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,   T_SLASHEQUAL,      2);
4865         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,   T_PERCENTEQUAL,    2);
4866         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,
4867                                                                 T_LESSLESSEQUAL, 2);
4868         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,
4869                                                           T_GREATERGREATEREQUAL, 2);
4870         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN,
4871                                                                      T_ANDEQUAL, 2);
4872         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,
4873                                                                     T_PIPEEQUAL, 2);
4874         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN,
4875                                                                    T_CARETEQUAL, 2);
4876
4877         register_infix_parser(parse_EXPR_BINARY_COMMA,        ',',               1);
4878
4879         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-',      25);
4880         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+',      25);
4881         register_expression_parser(parse_EXPR_UNARY_NOT,              '!',      25);
4882         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~',      25);
4883         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*',      25);
4884         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&',      25);
4885         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT,
4886                                                                   T_PLUSPLUS,   25);
4887         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT,
4888                                                                   T_MINUSMINUS, 25);
4889         register_expression_parser(parse_sizeof,                      T_sizeof, 25);
4890         register_expression_parser(parse_alignof,                T___alignof__, 25);
4891         register_expression_parser(parse_extension,            T___extension__, 25);
4892         register_expression_parser(parse_builtin_classify_type,
4893                                                      T___builtin_classify_type, 25);
4894 }
4895
4896 /**
4897  * Parse a asm statement constraints specification.
4898  */
4899 static asm_constraint_t *parse_asm_constraints(void)
4900 {
4901         asm_constraint_t *result = NULL;
4902         asm_constraint_t *last   = NULL;
4903
4904         while(token.type == T_STRING_LITERAL || token.type == '[') {
4905                 asm_constraint_t *constraint = allocate_ast_zero(sizeof(constraint[0]));
4906                 memset(constraint, 0, sizeof(constraint[0]));
4907
4908                 if(token.type == '[') {
4909                         eat('[');
4910                         if(token.type != T_IDENTIFIER) {
4911                                 parse_error_expected("while parsing asm constraint",
4912                                                      T_IDENTIFIER, 0);
4913                                 return NULL;
4914                         }
4915                         constraint->symbol = token.v.symbol;
4916
4917                         expect(']');
4918                 }
4919
4920                 constraint->constraints = parse_string_literals();
4921                 expect('(');
4922                 constraint->expression = parse_expression();
4923                 expect(')');
4924
4925                 if(last != NULL) {
4926                         last->next = constraint;
4927                 } else {
4928                         result = constraint;
4929                 }
4930                 last = constraint;
4931
4932                 if(token.type != ',')
4933                         break;
4934                 eat(',');
4935         }
4936
4937         return result;
4938 }
4939
4940 /**
4941  * Parse a asm statement clobber specification.
4942  */
4943 static asm_clobber_t *parse_asm_clobbers(void)
4944 {
4945         asm_clobber_t *result = NULL;
4946         asm_clobber_t *last   = NULL;
4947
4948         while(token.type == T_STRING_LITERAL) {
4949                 asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
4950                 clobber->clobber       = parse_string_literals();
4951
4952                 if(last != NULL) {
4953                         last->next = clobber;
4954                 } else {
4955                         result = clobber;
4956                 }
4957                 last = clobber;
4958
4959                 if(token.type != ',')
4960                         break;
4961                 eat(',');
4962         }
4963
4964         return result;
4965 }
4966
4967 /**
4968  * Parse an asm statement.
4969  */
4970 static statement_t *parse_asm_statement(void)
4971 {
4972         eat(T_asm);
4973
4974         statement_t *statement          = allocate_statement_zero(STATEMENT_ASM);
4975         statement->base.source_position = token.source_position;
4976
4977         asm_statement_t *asm_statement = &statement->asms;
4978
4979         if(token.type == T_volatile) {
4980                 next_token();
4981                 asm_statement->is_volatile = true;
4982         }
4983
4984         expect('(');
4985         asm_statement->asm_text = parse_string_literals();
4986
4987         if(token.type != ':')
4988                 goto end_of_asm;
4989         eat(':');
4990
4991         asm_statement->inputs = parse_asm_constraints();
4992         if(token.type != ':')
4993                 goto end_of_asm;
4994         eat(':');
4995
4996         asm_statement->outputs = parse_asm_constraints();
4997         if(token.type != ':')
4998                 goto end_of_asm;
4999         eat(':');
5000
5001         asm_statement->clobbers = parse_asm_clobbers();
5002
5003 end_of_asm:
5004         expect(')');
5005         expect(';');
5006         return statement;
5007 }
5008
5009 /**
5010  * Parse a case statement.
5011  */
5012 static statement_t *parse_case_statement(void)
5013 {
5014         eat(T_case);
5015
5016         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
5017
5018         statement->base.source_position  = token.source_position;
5019         statement->case_label.expression = parse_expression();
5020
5021         expect(':');
5022
5023         if (! is_constant_expression(statement->case_label.expression)) {
5024                 errorf(statement->base.source_position,
5025                         "case label does not reduce to an integer constant");
5026         } else {
5027                 /* TODO: check if the case label is already known */
5028                 if (current_switch != NULL) {
5029                         /* link all cases into the switch statement */
5030                         if (current_switch->last_case == NULL) {
5031                                 current_switch->first_case =
5032                                 current_switch->last_case  = &statement->case_label;
5033                         } else {
5034                                 current_switch->last_case->next = &statement->case_label;
5035                         }
5036                 } else {
5037                         errorf(statement->base.source_position,
5038                                 "case label not within a switch statement");
5039                 }
5040         }
5041         statement->case_label.statement = parse_statement();
5042
5043         return statement;
5044 }
5045
5046 /**
5047  * Finds an existing default label of a switch statement.
5048  */
5049 static case_label_statement_t *
5050 find_default_label(const switch_statement_t *statement)
5051 {
5052         for (case_label_statement_t *label = statement->first_case;
5053              label != NULL;
5054                  label = label->next) {
5055                 if (label->expression == NULL)
5056                         return label;
5057         }
5058         return NULL;
5059 }
5060
5061 /**
5062  * Parse a default statement.
5063  */
5064 static statement_t *parse_default_statement(void)
5065 {
5066         eat(T_default);
5067
5068         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
5069
5070         statement->base.source_position = token.source_position;
5071
5072         expect(':');
5073         if (current_switch != NULL) {
5074                 const case_label_statement_t *def_label = find_default_label(current_switch);
5075                 if (def_label != NULL) {
5076                         errorf(HERE, "multiple default labels in one switch");
5077                         errorf(def_label->base.source_position,
5078                                 "this is the first default label");
5079                 } else {
5080                         /* link all cases into the switch statement */
5081                         if (current_switch->last_case == NULL) {
5082                                 current_switch->first_case =
5083                                         current_switch->last_case  = &statement->case_label;
5084                         } else {
5085                                 current_switch->last_case->next = &statement->case_label;
5086                         }
5087                 }
5088         } else {
5089                 errorf(statement->base.source_position,
5090                         "'default' label not within a switch statement");
5091         }
5092         statement->label.statement = parse_statement();
5093
5094         return statement;
5095 }
5096
5097 /**
5098  * Return the declaration for a given label symbol or create a new one.
5099  */
5100 static declaration_t *get_label(symbol_t *symbol)
5101 {
5102         declaration_t *candidate = get_declaration(symbol, NAMESPACE_LABEL);
5103         assert(current_function != NULL);
5104         /* if we found a label in the same function, then we already created the
5105          * declaration */
5106         if(candidate != NULL
5107                         && candidate->parent_scope == &current_function->scope) {
5108                 return candidate;
5109         }
5110
5111         /* otherwise we need to create a new one */
5112         declaration_t *const declaration = allocate_declaration_zero();
5113         declaration->namespc       = NAMESPACE_LABEL;
5114         declaration->symbol        = symbol;
5115
5116         label_push(declaration);
5117
5118         return declaration;
5119 }
5120
5121 /**
5122  * Parse a label statement.
5123  */
5124 static statement_t *parse_label_statement(void)
5125 {
5126         assert(token.type == T_IDENTIFIER);
5127         symbol_t *symbol = token.v.symbol;
5128         next_token();
5129
5130         declaration_t *label = get_label(symbol);
5131
5132         /* if source position is already set then the label is defined twice,
5133          * otherwise it was just mentioned in a goto so far */
5134         if(label->source_position.input_name != NULL) {
5135                 errorf(HERE, "duplicate label '%Y'", symbol);
5136                 errorf(label->source_position, "previous definition of '%Y' was here",
5137                        symbol);
5138         } else {
5139                 label->source_position = token.source_position;
5140         }
5141
5142         statement_t *statement = allocate_statement_zero(STATEMENT_LABEL);
5143
5144         statement->base.source_position = token.source_position;
5145         statement->label.label          = label;
5146
5147         eat(':');
5148
5149         if(token.type == '}') {
5150                 /* TODO only warn? */
5151                 errorf(HERE, "label at end of compound statement");
5152                 return statement;
5153         } else {
5154                 if (token.type == ';') {
5155                         /* eat an empty statement here, to avoid the warning about an empty
5156                          * after a label.  label:; is commonly used to have a label before
5157                          * a }. */
5158                         next_token();
5159                 } else {
5160                         statement->label.statement = parse_statement();
5161                 }
5162         }
5163
5164         /* remember the labels's in a list for later checking */
5165         if (label_last == NULL) {
5166                 label_first = &statement->label;
5167         } else {
5168                 label_last->next = &statement->label;
5169         }
5170         label_last = &statement->label;
5171
5172         return statement;
5173 }
5174
5175 /**
5176  * Parse an if statement.
5177  */
5178 static statement_t *parse_if(void)
5179 {
5180         eat(T_if);
5181
5182         statement_t *statement          = allocate_statement_zero(STATEMENT_IF);
5183         statement->base.source_position = token.source_position;
5184
5185         expect('(');
5186         statement->ifs.condition = parse_expression();
5187         expect(')');
5188
5189         statement->ifs.true_statement = parse_statement();
5190         if(token.type == T_else) {
5191                 next_token();
5192                 statement->ifs.false_statement = parse_statement();
5193         }
5194
5195         return statement;
5196 }
5197
5198 /**
5199  * Parse a switch statement.
5200  */
5201 static statement_t *parse_switch(void)
5202 {
5203         eat(T_switch);
5204
5205         statement_t *statement          = allocate_statement_zero(STATEMENT_SWITCH);
5206         statement->base.source_position = token.source_position;
5207
5208         expect('(');
5209         expression_t *const expr = parse_expression();
5210         type_t       *      type = skip_typeref(expr->base.type);
5211         if (is_type_integer(type)) {
5212                 type = promote_integer(type);
5213         } else if (is_type_valid(type)) {
5214                 errorf(expr->base.source_position,
5215                        "switch quantity is not an integer, but '%T'", type);
5216                 type = type_error_type;
5217         }
5218         statement->switchs.expression = create_implicit_cast(expr, type);
5219         expect(')');
5220
5221         switch_statement_t *rem = current_switch;
5222         current_switch          = &statement->switchs;
5223         statement->switchs.body = parse_statement();
5224         current_switch          = rem;
5225
5226         if (warning.switch_default
5227                         && find_default_label(&statement->switchs) == NULL) {
5228                 warningf(statement->base.source_position, "switch has no default case");
5229         }
5230
5231         return statement;
5232 }
5233
5234 static statement_t *parse_loop_body(statement_t *const loop)
5235 {
5236         statement_t *const rem = current_loop;
5237         current_loop = loop;
5238
5239         statement_t *const body = parse_statement();
5240
5241         current_loop = rem;
5242         return body;
5243 }
5244
5245 /**
5246  * Parse a while statement.
5247  */
5248 static statement_t *parse_while(void)
5249 {
5250         eat(T_while);
5251
5252         statement_t *statement          = allocate_statement_zero(STATEMENT_WHILE);
5253         statement->base.source_position = token.source_position;
5254
5255         expect('(');
5256         statement->whiles.condition = parse_expression();
5257         expect(')');
5258
5259         statement->whiles.body = parse_loop_body(statement);
5260
5261         return statement;
5262 }
5263
5264 /**
5265  * Parse a do statement.
5266  */
5267 static statement_t *parse_do(void)
5268 {
5269         eat(T_do);
5270
5271         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
5272
5273         statement->base.source_position = token.source_position;
5274
5275         statement->do_while.body = parse_loop_body(statement);
5276
5277         expect(T_while);
5278         expect('(');
5279         statement->do_while.condition = parse_expression();
5280         expect(')');
5281         expect(';');
5282
5283         return statement;
5284 }
5285
5286 /**
5287  * Parse a for statement.
5288  */
5289 static statement_t *parse_for(void)
5290 {
5291         eat(T_for);
5292
5293         statement_t *statement          = allocate_statement_zero(STATEMENT_FOR);
5294         statement->base.source_position = token.source_position;
5295
5296         expect('(');
5297
5298         int      top        = environment_top();
5299         scope_t *last_scope = scope;
5300         set_scope(&statement->fors.scope);
5301
5302         if(token.type != ';') {
5303                 if(is_declaration_specifier(&token, false)) {
5304                         parse_declaration(record_declaration);
5305                 } else {
5306                         statement->fors.initialisation = parse_expression();
5307                         expect(';');
5308                 }
5309         } else {
5310                 expect(';');
5311         }
5312
5313         if(token.type != ';') {
5314                 statement->fors.condition = parse_expression();
5315         }
5316         expect(';');
5317         if(token.type != ')') {
5318                 statement->fors.step = parse_expression();
5319         }
5320         expect(')');
5321         statement->fors.body = parse_loop_body(statement);
5322
5323         assert(scope == &statement->fors.scope);
5324         set_scope(last_scope);
5325         environment_pop_to(top);
5326
5327         return statement;
5328 }
5329
5330 /**
5331  * Parse a goto statement.
5332  */
5333 static statement_t *parse_goto(void)
5334 {
5335         eat(T_goto);
5336
5337         if(token.type != T_IDENTIFIER) {
5338                 parse_error_expected("while parsing goto", T_IDENTIFIER, 0);
5339                 eat_statement();
5340                 return NULL;
5341         }
5342         symbol_t *symbol = token.v.symbol;
5343         next_token();
5344
5345         declaration_t *label = get_label(symbol);
5346
5347         statement_t *statement          = allocate_statement_zero(STATEMENT_GOTO);
5348         statement->base.source_position = token.source_position;
5349
5350         statement->gotos.label = label;
5351
5352         /* remember the goto's in a list for later checking */
5353         if (goto_last == NULL) {
5354                 goto_first = &statement->gotos;
5355         } else {
5356                 goto_last->next = &statement->gotos;
5357         }
5358         goto_last = &statement->gotos;
5359
5360         expect(';');
5361
5362         return statement;
5363 }
5364
5365 /**
5366  * Parse a continue statement.
5367  */
5368 static statement_t *parse_continue(void)
5369 {
5370         statement_t *statement;
5371         if (current_loop == NULL) {
5372                 errorf(HERE, "continue statement not within loop");
5373                 statement = NULL;
5374         } else {
5375                 statement = allocate_statement_zero(STATEMENT_CONTINUE);
5376
5377                 statement->base.source_position = token.source_position;
5378         }
5379
5380         eat(T_continue);
5381         expect(';');
5382
5383         return statement;
5384 }
5385
5386 /**
5387  * Parse a break statement.
5388  */
5389 static statement_t *parse_break(void)
5390 {
5391         statement_t *statement;
5392         if (current_switch == NULL && current_loop == NULL) {
5393                 errorf(HERE, "break statement not within loop or switch");
5394                 statement = NULL;
5395         } else {
5396                 statement = allocate_statement_zero(STATEMENT_BREAK);
5397
5398                 statement->base.source_position = token.source_position;
5399         }
5400
5401         eat(T_break);
5402         expect(';');
5403
5404         return statement;
5405 }
5406
5407 /**
5408  * Check if a given declaration represents a local variable.
5409  */
5410 static bool is_local_var_declaration(const declaration_t *declaration) {
5411         switch ((storage_class_tag_t) declaration->storage_class) {
5412         case STORAGE_CLASS_NONE:
5413         case STORAGE_CLASS_AUTO:
5414         case STORAGE_CLASS_REGISTER: {
5415                 const type_t *type = skip_typeref(declaration->type);
5416                 if(is_type_function(type)) {
5417                         return false;
5418                 } else {
5419                         return true;
5420                 }
5421         }
5422         default:
5423                 return false;
5424         }
5425 }
5426
5427 /**
5428  * Check if a given declaration represents a variable.
5429  */
5430 static bool is_var_declaration(const declaration_t *declaration) {
5431         switch ((storage_class_tag_t) declaration->storage_class) {
5432         case STORAGE_CLASS_NONE:
5433         case STORAGE_CLASS_EXTERN:
5434         case STORAGE_CLASS_STATIC:
5435         case STORAGE_CLASS_AUTO:
5436         case STORAGE_CLASS_REGISTER:
5437         case STORAGE_CLASS_THREAD:
5438         case STORAGE_CLASS_THREAD_EXTERN:
5439         case STORAGE_CLASS_THREAD_STATIC: {
5440                 const type_t *type = skip_typeref(declaration->type);
5441                 if(is_type_function(type)) {
5442                         return false;
5443                 } else {
5444                         return true;
5445                 }
5446         }
5447         default:
5448                 return false;
5449         }
5450 }
5451
5452 /**
5453  * Check if a given expression represents a local variable.
5454  */
5455 static bool is_local_variable(const expression_t *expression)
5456 {
5457         if (expression->base.kind != EXPR_REFERENCE) {
5458                 return false;
5459         }
5460         const declaration_t *declaration = expression->reference.declaration;
5461         return is_local_var_declaration(declaration);
5462 }
5463
5464 /**
5465  * Check if a given expression represents a local variable and
5466  * return its declaration then, else return NULL.
5467  */
5468 declaration_t *expr_is_variable(const expression_t *expression)
5469 {
5470         if (expression->base.kind != EXPR_REFERENCE) {
5471                 return NULL;
5472         }
5473         declaration_t *declaration = expression->reference.declaration;
5474         if (is_var_declaration(declaration))
5475                 return declaration;
5476         return NULL;
5477 }
5478
5479 /**
5480  * Parse a return statement.
5481  */
5482 static statement_t *parse_return(void)
5483 {
5484         eat(T_return);
5485
5486         statement_t *statement          = allocate_statement_zero(STATEMENT_RETURN);
5487         statement->base.source_position = token.source_position;
5488
5489         expression_t *return_value = NULL;
5490         if(token.type != ';') {
5491                 return_value = parse_expression();
5492         }
5493         expect(';');
5494
5495         const type_t *const func_type = current_function->type;
5496         assert(is_type_function(func_type));
5497         type_t *const return_type = skip_typeref(func_type->function.return_type);
5498
5499         if(return_value != NULL) {
5500                 type_t *return_value_type = skip_typeref(return_value->base.type);
5501
5502                 if(is_type_atomic(return_type, ATOMIC_TYPE_VOID)
5503                                 && !is_type_atomic(return_value_type, ATOMIC_TYPE_VOID)) {
5504                         warningf(statement->base.source_position,
5505                                  "'return' with a value, in function returning void");
5506                         return_value = NULL;
5507                 } else {
5508                         type_t *const res_type = semantic_assign(return_type,
5509                                 return_value, "'return'");
5510                         if (res_type == NULL) {
5511                                 errorf(statement->base.source_position,
5512                                        "cannot return something of type '%T' in function returning '%T'",
5513                                        return_value->base.type, return_type);
5514                         } else {
5515                                 return_value = create_implicit_cast(return_value, res_type);
5516                         }
5517                 }
5518                 /* check for returning address of a local var */
5519                 if (return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
5520                         const expression_t *expression = return_value->unary.value;
5521                         if (is_local_variable(expression)) {
5522                                 warningf(statement->base.source_position,
5523                                          "function returns address of local variable");
5524                         }
5525                 }
5526         } else {
5527                 if(!is_type_atomic(return_type, ATOMIC_TYPE_VOID)) {
5528                         warningf(statement->base.source_position,
5529                                  "'return' without value, in function returning non-void");
5530                 }
5531         }
5532         statement->returns.value = return_value;
5533
5534         return statement;
5535 }
5536
5537 /**
5538  * Parse a declaration statement.
5539  */
5540 static statement_t *parse_declaration_statement(void)
5541 {
5542         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
5543
5544         statement->base.source_position = token.source_position;
5545
5546         declaration_t *before = last_declaration;
5547         parse_declaration(record_declaration);
5548
5549         if(before == NULL) {
5550                 statement->declaration.declarations_begin = scope->declarations;
5551         } else {
5552                 statement->declaration.declarations_begin = before->next;
5553         }
5554         statement->declaration.declarations_end = last_declaration;
5555
5556         return statement;
5557 }
5558
5559 /**
5560  * Parse an expression statement, ie. expr ';'.
5561  */
5562 static statement_t *parse_expression_statement(void)
5563 {
5564         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
5565
5566         statement->base.source_position  = token.source_position;
5567         expression_t *const expr         = parse_expression();
5568         statement->expression.expression = expr;
5569
5570         if (warning.unused_value  && !expression_has_effect(expr)) {
5571                 warningf(expr->base.source_position, "statement has no effect");
5572         }
5573
5574         expect(';');
5575
5576         return statement;
5577 }
5578
5579 /**
5580  * Parse a statement.
5581  */
5582 static statement_t *parse_statement(void)
5583 {
5584         statement_t   *statement = NULL;
5585
5586         /* declaration or statement */
5587         switch(token.type) {
5588         case T_asm:
5589                 statement = parse_asm_statement();
5590                 break;
5591
5592         case T_case:
5593                 statement = parse_case_statement();
5594                 break;
5595
5596         case T_default:
5597                 statement = parse_default_statement();
5598                 break;
5599
5600         case '{':
5601                 statement = parse_compound_statement();
5602                 break;
5603
5604         case T_if:
5605                 statement = parse_if();
5606                 break;
5607
5608         case T_switch:
5609                 statement = parse_switch();
5610                 break;
5611
5612         case T_while:
5613                 statement = parse_while();
5614                 break;
5615
5616         case T_do:
5617                 statement = parse_do();
5618                 break;
5619
5620         case T_for:
5621                 statement = parse_for();
5622                 break;
5623
5624         case T_goto:
5625                 statement = parse_goto();
5626                 break;
5627
5628         case T_continue:
5629                 statement = parse_continue();
5630                 break;
5631
5632         case T_break:
5633                 statement = parse_break();
5634                 break;
5635
5636         case T_return:
5637                 statement = parse_return();
5638                 break;
5639
5640         case ';':
5641                 if (warning.empty_statement) {
5642                         warningf(HERE, "statement is empty");
5643                 }
5644                 next_token();
5645                 statement = NULL;
5646                 break;
5647
5648         case T_IDENTIFIER:
5649                 if(look_ahead(1)->type == ':') {
5650                         statement = parse_label_statement();
5651                         break;
5652                 }
5653
5654                 if(is_typedef_symbol(token.v.symbol)) {
5655                         statement = parse_declaration_statement();
5656                         break;
5657                 }
5658
5659                 statement = parse_expression_statement();
5660                 break;
5661
5662         case T___extension__:
5663                 /* this can be a prefix to a declaration or an expression statement */
5664                 /* we simply eat it now and parse the rest with tail recursion */
5665                 do {
5666                         next_token();
5667                 } while(token.type == T___extension__);
5668                 statement = parse_statement();
5669                 break;
5670
5671         DECLARATION_START
5672                 statement = parse_declaration_statement();
5673                 break;
5674
5675         default:
5676                 statement = parse_expression_statement();
5677                 break;
5678         }
5679
5680         assert(statement == NULL
5681                         || statement->base.source_position.input_name != NULL);
5682
5683         return statement;
5684 }
5685
5686 /**
5687  * Parse a compound statement.
5688  */
5689 static statement_t *parse_compound_statement(void)
5690 {
5691         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
5692
5693         statement->base.source_position = token.source_position;
5694
5695         eat('{');
5696
5697         int      top        = environment_top();
5698         scope_t *last_scope = scope;
5699         set_scope(&statement->compound.scope);
5700
5701         statement_t *last_statement = NULL;
5702
5703         while(token.type != '}' && token.type != T_EOF) {
5704                 statement_t *sub_statement = parse_statement();
5705                 if(sub_statement == NULL)
5706                         continue;
5707
5708                 if(last_statement != NULL) {
5709                         last_statement->base.next = sub_statement;
5710                 } else {
5711                         statement->compound.statements = sub_statement;
5712                 }
5713
5714                 while(sub_statement->base.next != NULL)
5715                         sub_statement = sub_statement->base.next;
5716
5717                 last_statement = sub_statement;
5718         }
5719
5720         if(token.type == '}') {
5721                 next_token();
5722         } else {
5723                 errorf(statement->base.source_position,
5724                        "end of file while looking for closing '}'");
5725         }
5726
5727         assert(scope == &statement->compound.scope);
5728         set_scope(last_scope);
5729         environment_pop_to(top);
5730
5731         return statement;
5732 }
5733
5734 /**
5735  * Initialize builtin types.
5736  */
5737 static void initialize_builtin_types(void)
5738 {
5739         type_intmax_t    = make_global_typedef("__intmax_t__",      type_long_long);
5740         type_size_t      = make_global_typedef("__SIZE_TYPE__",     type_unsigned_long);
5741         type_ssize_t     = make_global_typedef("__SSIZE_TYPE__",    type_long);
5742         type_ptrdiff_t   = make_global_typedef("__PTRDIFF_TYPE__",  type_long);
5743         type_uintmax_t   = make_global_typedef("__uintmax_t__",     type_unsigned_long_long);
5744         type_uptrdiff_t  = make_global_typedef("__UPTRDIFF_TYPE__", type_unsigned_long);
5745         type_wchar_t     = make_global_typedef("__WCHAR_TYPE__",    type_int);
5746         type_wint_t      = make_global_typedef("__WINT_TYPE__",     type_int);
5747
5748         type_intmax_t_ptr  = make_pointer_type(type_intmax_t,  TYPE_QUALIFIER_NONE);
5749         type_ptrdiff_t_ptr = make_pointer_type(type_ptrdiff_t, TYPE_QUALIFIER_NONE);
5750         type_ssize_t_ptr   = make_pointer_type(type_ssize_t,   TYPE_QUALIFIER_NONE);
5751         type_wchar_t_ptr   = make_pointer_type(type_wchar_t,   TYPE_QUALIFIER_NONE);
5752 }
5753
5754 /**
5755  * Check for unused global static functions and variables
5756  */
5757 static void check_unused_globals(void)
5758 {
5759         if (!warning.unused_function && !warning.unused_variable)
5760                 return;
5761
5762         for (const declaration_t *decl = global_scope->declarations; decl != NULL; decl = decl->next) {
5763                 if (decl->used || decl->storage_class != STORAGE_CLASS_STATIC)
5764                         continue;
5765
5766                 type_t *const type = decl->type;
5767                 const char *s;
5768                 if (is_type_function(skip_typeref(type))) {
5769                         if (!warning.unused_function || decl->is_inline)
5770                                 continue;
5771
5772                         s = (decl->init.statement != NULL ? "defined" : "declared");
5773                 } else {
5774                         if (!warning.unused_variable)
5775                                 continue;
5776
5777                         s = "defined";
5778                 }
5779
5780                 warningf(decl->source_position, "'%#T' %s but not used",
5781                         type, decl->symbol, s);
5782         }
5783 }
5784
5785 /**
5786  * Parse a translation unit.
5787  */
5788 static translation_unit_t *parse_translation_unit(void)
5789 {
5790         translation_unit_t *unit = allocate_ast_zero(sizeof(unit[0]));
5791
5792         assert(global_scope == NULL);
5793         global_scope = &unit->scope;
5794
5795         assert(scope == NULL);
5796         set_scope(&unit->scope);
5797
5798         initialize_builtin_types();
5799
5800         while(token.type != T_EOF) {
5801                 if (token.type == ';') {
5802                         /* TODO error in strict mode */
5803                         warningf(HERE, "stray ';' outside of function");
5804                         next_token();
5805                 } else {
5806                         parse_external_declaration();
5807                 }
5808         }
5809
5810         assert(scope == &unit->scope);
5811         scope          = NULL;
5812         last_declaration = NULL;
5813
5814         assert(global_scope == &unit->scope);
5815         check_unused_globals();
5816         global_scope = NULL;
5817
5818         return unit;
5819 }
5820
5821 /**
5822  * Parse the input.
5823  *
5824  * @return  the translation unit or NULL if errors occurred.
5825  */
5826 translation_unit_t *parse(void)
5827 {
5828         environment_stack = NEW_ARR_F(stack_entry_t, 0);
5829         label_stack       = NEW_ARR_F(stack_entry_t, 0);
5830         diagnostic_count  = 0;
5831         error_count       = 0;
5832         warning_count     = 0;
5833
5834         type_set_output(stderr);
5835         ast_set_output(stderr);
5836
5837         lookahead_bufpos = 0;
5838         for(int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
5839                 next_token();
5840         }
5841         translation_unit_t *unit = parse_translation_unit();
5842
5843         DEL_ARR_F(environment_stack);
5844         DEL_ARR_F(label_stack);
5845
5846         if(error_count > 0)
5847                 return NULL;
5848
5849         return unit;
5850 }
5851
5852 /**
5853  * Initialize the parser.
5854  */
5855 void init_parser(void)
5856 {
5857         init_expression_parsers();
5858         obstack_init(&temp_obst);
5859
5860         symbol_t *const va_list_sym = symbol_table_insert("__builtin_va_list");
5861         type_valist = create_builtin_type(va_list_sym, type_void_ptr);
5862 }
5863
5864 /**
5865  * Terminate the parser.
5866  */
5867 void exit_parser(void)
5868 {
5869         obstack_free(&temp_obst, NULL);
5870 }