nsz Git - cparser/blob - parser.c

   1 /*
   2  * This file is part of cparser.
   3  * Copyright (C) 2012 Matthias Braun <matze@braunis.de>
   4  */
   5 #include <config.h>
   6
   7 #include <assert.h>
   8 #include <ctype.h>
   9 #include <stdarg.h>
  10 #include <stdbool.h>
  11
  12 #include "adt/strutil.h"
  13 #include "adt/util.h"
  14 #include "parser.h"
  15 #include "diagnostic.h"
  16 #include "format_check.h"
  17 #include "preprocessor.h"
  18 #include "symbol_t.h"
  19 #include "symbol_table.h"
  20 #include "token_t.h"
  21 #include "types.h"
  22 #include "type_t.h"
  23 #include "type_hash.h"
  24 #include "ast_t.h"
  25 #include "attribute_t.h"
  26 #include "lang_features.h"
  27 #include "walk.h"
  28 #include "warning.h"
  29 #include "printer.h"
  30 #include "ast2firm.h"
  31 #include "adt/error.h"
  32 #include "adt/array.h"
  33
  34 //#define PRINT_TOKENS
  35 #define MAX_LOOKAHEAD 1
  36
  37 typedef struct {
  38         entity_t           *old_entity;
  39         symbol_t           *symbol;
  40         entity_namespace_t  namespc;
  41 } stack_entry_t;
  42
  43 typedef struct declaration_specifiers_t  declaration_specifiers_t;
  44 struct declaration_specifiers_t {
  45         position_t      pos;
  46         storage_class_t storage_class;
  47         bool            is_inline    : 1;
  48         bool            thread_local : 1;
  49         attribute_t    *attributes;        /**< list of attributes */
  50         type_t         *type;
  51 };
  52
  53 /**
  54  * An environment for parsing initializers (and compound literals).
  55  */
  56 typedef struct parse_initializer_env_t {
  57         type_t     *type;   /**< the type of the initializer. In case of an
  58                                  array type with unspecified size this gets
  59                                  adjusted to the actual size. */
  60         entity_t   *entity; /**< the variable that is initialized if any */
  61         bool        must_be_constant;
  62 } parse_initializer_env_t;
  63
  64 typedef entity_t* (*parsed_declaration_func) (entity_t *declaration, bool is_definition);
  65
  66 /** The current token. */
  67 static token_t              token;
  68 /** The lookahead ring-buffer. */
  69 static token_t              lookahead_buffer[MAX_LOOKAHEAD];
  70 /** Position of the next token in the lookahead buffer. */
  71 static size_t               lookahead_bufpos;
  72 static stack_entry_t       *environment_stack = NULL;
  73 static stack_entry_t       *label_stack       = NULL;
  74 static scope_t             *file_scope        = NULL;
  75 static scope_t             *current_scope     = NULL;
  76 /** Point to the current function declaration if inside a function. */
  77 static function_t          *current_function  = NULL;
  78 static entity_t            *current_entity    = NULL;
  79 static switch_statement_t  *current_switch    = NULL;
  80 static statement_t         *current_loop      = NULL;
  81 static statement_t         *current_parent    = NULL;
  82 static ms_try_statement_t  *current_try       = NULL;
  83 static linkage_kind_t       current_linkage;
  84 static goto_statement_t    *goto_first        = NULL;
  85 static goto_statement_t   **goto_anchor       = NULL;
  86 static label_statement_t   *label_first       = NULL;
  87 static label_statement_t  **label_anchor      = NULL;
  88 /** current translation unit. */
  89 static translation_unit_t  *unit              = NULL;
  90 /** true if we are in an __extension__ context. */
  91 static bool                 in_gcc_extension  = false;
  92 static struct obstack       temp_obst;
  93 static entity_t            *anonymous_entity;
  94 static declaration_t      **incomplete_arrays;
  95 static elf_visibility_tag_t default_visibility = ELF_VISIBILITY_DEFAULT;
  96
  97
  98 #define PUSH_CURRENT_ENTITY(entity) \
  99         entity_t *const new_current_entity = (entity); \
 100         entity_t *const old_current_entity = current_entity; \
 101         ((void)(current_entity = new_current_entity))
 102 #define POP_CURRENT_ENTITY() (assert(current_entity == new_current_entity), (void)(current_entity = old_current_entity))
 103
 104 #define PUSH_PARENT(stmt) \
 105         statement_t *const new_parent = (stmt); \
 106         statement_t *const old_parent = current_parent; \
 107         ((void)(current_parent = new_parent))
 108 #define POP_PARENT() (assert(current_parent == new_parent), (void)(current_parent = old_parent))
 109
 110 #define PUSH_SCOPE(scope) \
 111         size_t   const top       = environment_top(); \
 112         scope_t *const new_scope = (scope); \
 113         scope_t *const old_scope = (new_scope ? scope_push(new_scope) : NULL)
 114 #define PUSH_SCOPE_STATEMENT(scope) PUSH_SCOPE(c_mode & (_C99 | _CXX) ? (scope) : NULL)
 115 #define POP_SCOPE() (new_scope ? assert(current_scope == new_scope), scope_pop(old_scope), environment_pop_to(top) : (void)0)
 116
 117 #define PUSH_EXTENSION() \
 118         (void)0; \
 119         bool const old_gcc_extension = in_gcc_extension; \
 120         while (accept(T___extension__)) { \
 121                 in_gcc_extension = true; \
 122         } \
 123         do {} while (0)
 124 #define POP_EXTENSION() \
 125         ((void)(in_gcc_extension = old_gcc_extension))
 126
 127 /** The token anchor set */
 128 static unsigned short token_anchor_set[T_LAST_TOKEN];
 129
 130 /** The current source position. */
 131 #define HERE (&token.base.pos)
 132
 133 /** true if we are in GCC mode. */
 134 #define GNU_MODE ((c_mode & _GNUC) || in_gcc_extension)
 135
 136 static statement_t *parse_compound_statement(bool inside_expression_statement);
 137 static statement_t *parse_statement(void);
 138
 139 static expression_t *parse_subexpression(precedence_t);
 140 static expression_t *parse_expression(void);
 141 static type_t       *parse_typename(void);
 142 static void          parse_externals(void);
 143 static void          parse_external(void);
 144
 145 static void parse_compound_type_entries(compound_t *compound_declaration);
 146
 147 static void check_call_argument(type_t          *expected_type,
 148                                                                 call_argument_t *argument, unsigned pos);
 149
 150 typedef enum declarator_flags_t {
 151         DECL_FLAGS_NONE             = 0,
 152         DECL_MAY_BE_ABSTRACT        = 1U << 0,
 153         DECL_CREATE_COMPOUND_MEMBER = 1U << 1,
 154         DECL_IS_PARAMETER           = 1U << 2
 155 } declarator_flags_t;
 156
 157 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
 158                                   declarator_flags_t flags);
 159
 160 static void semantic_comparison(binary_expression_t *expression,
 161                                 bool is_relational);
 162
 163 #define STORAGE_CLASSES       \
 164         STORAGE_CLASSES_NO_EXTERN \
 165         case T_extern:
 166
 167 #define STORAGE_CLASSES_NO_EXTERN \
 168         case T_typedef:         \
 169         case T_static:          \
 170         case T_auto:            \
 171         case T_register:        \
 172         case T__Thread_local:
 173
 174 #define TYPE_QUALIFIERS     \
 175         case T_const:           \
 176         case T_restrict:        \
 177         case T_volatile:        \
 178         case T_inline:          \
 179         case T__forceinline:    \
 180         case T___attribute__:
 181
 182 #define COMPLEX_SPECIFIERS  \
 183         case T__Complex:
 184 #define IMAGINARY_SPECIFIERS \
 185         case T__Imaginary:
 186
 187 #define TYPE_SPECIFIERS       \
 188         case T__Bool:             \
 189         case T___builtin_va_list: \
 190         case T___typeof__:        \
 191         case T__declspec:         \
 192         case T_bool:              \
 193         case T_char:              \
 194         case T_double:            \
 195         case T_enum:              \
 196         case T_float:             \
 197         case T_int:               \
 198         case T_long:              \
 199         case T_short:             \
 200         case T_signed:            \
 201         case T_struct:            \
 202         case T_union:             \
 203         case T_unsigned:          \
 204         case T_void:              \
 205         case T_wchar_t:           \
 206         case T__int8:             \
 207         case T__int16:            \
 208         case T__int32:            \
 209         case T__int64:            \
 210         case T__int128:           \
 211         COMPLEX_SPECIFIERS        \
 212         IMAGINARY_SPECIFIERS
 213
 214 #define DECLARATION_START   \
 215         STORAGE_CLASSES         \
 216         TYPE_QUALIFIERS         \
 217         TYPE_SPECIFIERS
 218
 219 #define DECLARATION_START_NO_EXTERN \
 220         STORAGE_CLASSES_NO_EXTERN       \
 221         TYPE_QUALIFIERS                 \
 222         TYPE_SPECIFIERS
 223
 224 #define EXPRESSION_START              \
 225         case '!':                         \
 226         case '&':                         \
 227         case '(':                         \
 228         case '*':                         \
 229         case '+':                         \
 230         case '-':                         \
 231         case '~':                         \
 232         case T_ANDAND:                    \
 233         case T_CHARACTER_CONSTANT:        \
 234         case T_NUMBER:                    \
 235         case T_MINUSMINUS:                \
 236         case T_PLUSPLUS:                  \
 237         case T_STRING_LITERAL:            \
 238         case T__Alignof:                  \
 239         case T___FUNCDNAME__:             \
 240         case T___FUNCSIG__:               \
 241         case T___PRETTY_FUNCTION__:       \
 242         case T___builtin_classify_type:   \
 243         case T___builtin_constant_p:      \
 244         case T___builtin_isgreater:       \
 245         case T___builtin_isgreaterequal:  \
 246         case T___builtin_isless:          \
 247         case T___builtin_islessequal:     \
 248         case T___builtin_islessgreater:   \
 249         case T___builtin_isunordered:     \
 250         case T___builtin_offsetof:        \
 251         case T___builtin_va_arg:          \
 252         case T___builtin_va_copy:         \
 253         case T___builtin_va_start:        \
 254         case T___func__:                  \
 255         case T___noop:                    \
 256         case T__assume:                   \
 257         case T_delete:                    \
 258         case T_false:                     \
 259         case T_sizeof:                    \
 260         case T_throw:                     \
 261         case T_true:                      \
 262         case T___imag__:                  \
 263         case T___real__:
 264
 265 /**
 266  * Returns the size of a statement node.
 267  *
 268  * @param kind  the statement kind
 269  */
 270 static size_t get_statement_struct_size(statement_kind_t kind)
 271 {
 272         static const size_t sizes[] = {
 273                 [STATEMENT_ERROR]         = sizeof(statement_base_t),
 274                 [STATEMENT_EMPTY]         = sizeof(statement_base_t),
 275                 [STATEMENT_COMPOUND]      = sizeof(compound_statement_t),
 276                 [STATEMENT_RETURN]        = sizeof(return_statement_t),
 277                 [STATEMENT_DECLARATION]   = sizeof(declaration_statement_t),
 278                 [STATEMENT_IF]            = sizeof(if_statement_t),
 279                 [STATEMENT_SWITCH]        = sizeof(switch_statement_t),
 280                 [STATEMENT_EXPRESSION]    = sizeof(expression_statement_t),
 281                 [STATEMENT_CONTINUE]      = sizeof(statement_base_t),
 282                 [STATEMENT_BREAK]         = sizeof(statement_base_t),
 283                 [STATEMENT_COMPUTED_GOTO] = sizeof(computed_goto_statement_t),
 284                 [STATEMENT_GOTO]          = sizeof(goto_statement_t),
 285                 [STATEMENT_LABEL]         = sizeof(label_statement_t),
 286                 [STATEMENT_CASE_LABEL]    = sizeof(case_label_statement_t),
 287                 [STATEMENT_DO_WHILE]      = sizeof(do_while_statement_t),
 288                 [STATEMENT_FOR]           = sizeof(for_statement_t),
 289                 [STATEMENT_ASM]           = sizeof(asm_statement_t),
 290                 [STATEMENT_MS_TRY]        = sizeof(ms_try_statement_t),
 291                 [STATEMENT_LEAVE]         = sizeof(leave_statement_t)
 292         };
 293         assert((size_t)kind < lengthof(sizes));
 294         assert(sizes[kind] != 0);
 295         return sizes[kind];
 296 }
 297
 298 /**
 299  * Returns the size of an expression node.
 300  *
 301  * @param kind  the expression kind
 302  */
 303 static size_t get_expression_struct_size(expression_kind_t kind)
 304 {
 305         static const size_t sizes[] = {
 306                 [EXPR_ERROR]                      = sizeof(expression_base_t),
 307                 [EXPR_REFERENCE]                  = sizeof(reference_expression_t),
 308                 [EXPR_ENUM_CONSTANT]              = sizeof(reference_expression_t),
 309                 [EXPR_LITERAL_BOOLEAN]            = sizeof(literal_expression_t),
 310                 [EXPR_LITERAL_INTEGER]            = sizeof(literal_expression_t),
 311                 [EXPR_LITERAL_FLOATINGPOINT]      = sizeof(literal_expression_t),
 312                 [EXPR_LITERAL_CHARACTER]          = sizeof(string_literal_expression_t),
 313                 [EXPR_LITERAL_MS_NOOP]            = sizeof(literal_expression_t),
 314                 [EXPR_STRING_LITERAL]             = sizeof(string_literal_expression_t),
 315                 [EXPR_COMPOUND_LITERAL]           = sizeof(compound_literal_expression_t),
 316                 [EXPR_CALL]                       = sizeof(call_expression_t),
 317                 [EXPR_UNARY_FIRST]                = sizeof(unary_expression_t),
 318                 [EXPR_BINARY_FIRST]               = sizeof(binary_expression_t),
 319                 [EXPR_CONDITIONAL]                = sizeof(conditional_expression_t),
 320                 [EXPR_SELECT]                     = sizeof(select_expression_t),
 321                 [EXPR_ARRAY_ACCESS]               = sizeof(array_access_expression_t),
 322                 [EXPR_SIZEOF]                     = sizeof(typeprop_expression_t),
 323                 [EXPR_ALIGNOF]                    = sizeof(typeprop_expression_t),
 324                 [EXPR_CLASSIFY_TYPE]              = sizeof(classify_type_expression_t),
 325                 [EXPR_FUNCNAME]                   = sizeof(funcname_expression_t),
 326                 [EXPR_BUILTIN_CONSTANT_P]         = sizeof(builtin_constant_expression_t),
 327                 [EXPR_BUILTIN_TYPES_COMPATIBLE_P] = sizeof(builtin_types_compatible_expression_t),
 328                 [EXPR_OFFSETOF]                   = sizeof(offsetof_expression_t),
 329                 [EXPR_VA_START]                   = sizeof(va_start_expression_t),
 330                 [EXPR_VA_ARG]                     = sizeof(va_arg_expression_t),
 331                 [EXPR_VA_COPY]                    = sizeof(va_copy_expression_t),
 332                 [EXPR_STATEMENT]                  = sizeof(statement_expression_t),
 333                 [EXPR_LABEL_ADDRESS]              = sizeof(label_address_expression_t),
 334         };
 335         if (kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
 336                 return sizes[EXPR_UNARY_FIRST];
 337         }
 338         if (kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
 339                 return sizes[EXPR_BINARY_FIRST];
 340         }
 341         assert((size_t)kind < lengthof(sizes));
 342         assert(sizes[kind] != 0);
 343         return sizes[kind];
 344 }
 345
 346 /**
 347  * Allocate a statement node of given kind and initialize all
 348  * fields with zero. Sets its source position to the position
 349  * of the current token.
 350  */
 351 static statement_t *allocate_statement_zero(statement_kind_t kind)
 352 {
 353         size_t       size = get_statement_struct_size(kind);
 354         statement_t *res  = allocate_ast_zero(size);
 355
 356         res->base.kind   = kind;
 357         res->base.parent = current_parent;
 358         res->base.pos    = *HERE;
 359         return res;
 360 }
 361
 362 /**
 363  * Allocate an expression node of given kind and initialize all
 364  * fields with zero.
 365  *
 366  * @param kind  the kind of the expression to allocate
 367  */
 368 static expression_t *allocate_expression_zero(expression_kind_t kind)
 369 {
 370         size_t        size = get_expression_struct_size(kind);
 371         expression_t *res  = allocate_ast_zero(size);
 372
 373         res->base.kind = kind;
 374         res->base.type = type_error_type;
 375         res->base.pos  = *HERE;
 376         return res;
 377 }
 378
 379 /**
 380  * Creates a new invalid expression at the source position
 381  * of the current token.
 382  */
 383 static expression_t *create_error_expression(void)
 384 {
 385         expression_t *expression = allocate_expression_zero(EXPR_ERROR);
 386         expression->base.type = type_error_type;
 387         return expression;
 388 }
 389
 390 /**
 391  * Creates a new invalid statement.
 392  */
 393 static statement_t *create_error_statement(void)
 394 {
 395         return allocate_statement_zero(STATEMENT_ERROR);
 396 }
 397
 398 /**
 399  * Allocate a new empty statement.
 400  */
 401 static statement_t *create_empty_statement(void)
 402 {
 403         return allocate_statement_zero(STATEMENT_EMPTY);
 404 }
 405
 406 /**
 407  * Returns the size of an initializer node.
 408  *
 409  * @param kind  the initializer kind
 410  */
 411 static size_t get_initializer_size(initializer_kind_t kind)
 412 {
 413         static const size_t sizes[] = {
 414                 [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
 415                 [INITIALIZER_STRING]      = sizeof(initializer_value_t),
 416                 [INITIALIZER_LIST]        = sizeof(initializer_list_t),
 417                 [INITIALIZER_DESIGNATOR]  = sizeof(initializer_designator_t)
 418         };
 419         assert((size_t)kind < lengthof(sizes));
 420         assert(sizes[kind] != 0);
 421         return sizes[kind];
 422 }
 423
 424 /**
 425  * Allocate an initializer node of given kind and initialize all
 426  * fields with zero.
 427  */
 428 static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 429 {
 430         initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
 431         result->kind          = kind;
 432
 433         return result;
 434 }
 435
 436 /**
 437  * Returns the index of the top element of the environment stack.
 438  */
 439 static size_t environment_top(void)
 440 {
 441         return ARR_LEN(environment_stack);
 442 }
 443
 444 /**
 445  * Returns the index of the top element of the global label stack.
 446  */
 447 static size_t label_top(void)
 448 {
 449         return ARR_LEN(label_stack);
 450 }
 451
 452 /**
 453  * Return the next token.
 454  */
 455 static inline void next_token(void)
 456 {
 457         token                              = lookahead_buffer[lookahead_bufpos];
 458         lookahead_buffer[lookahead_bufpos] = pp_token;
 459         next_preprocessing_token();
 460
 461         lookahead_bufpos = (lookahead_bufpos + 1) % MAX_LOOKAHEAD;
 462
 463 #ifdef PRINT_TOKENS
 464         print_token(stderr, &token);
 465         fprintf(stderr, "\n");
 466 #endif
 467 }
 468
 469 static inline void eat(token_kind_t const kind)
 470 {
 471         assert(token.kind == kind);
 472         (void)kind;
 473         next_token();
 474 }
 475
 476 /**
 477  * Consume the current token, if it is of the expected kind.
 478  *
 479  * @param  kind  The kind of token to consume.
 480  * @return Whether the token was consumed.
 481  */
 482 static inline bool accept(token_kind_t const kind)
 483 {
 484         if (token.kind == kind) {
 485                 eat(kind);
 486                 return true;
 487         } else {
 488                 return false;
 489         }
 490 }
 491
 492 /**
 493  * Return the next token with a given lookahead.
 494  */
 495 static inline const token_t *look_ahead(size_t num)
 496 {
 497         assert(0 < num && num <= MAX_LOOKAHEAD);
 498         size_t pos = (lookahead_bufpos + num - 1) % MAX_LOOKAHEAD;
 499         return &lookahead_buffer[pos];
 500 }
 501
 502 /**
 503  * Adds a token type to the token type anchor set (a multi-set).
 504  */
 505 static void add_anchor_token(token_kind_t const token_kind)
 506 {
 507         assert(token_kind < T_LAST_TOKEN);
 508         ++token_anchor_set[token_kind];
 509 }
 510
 511 /**
 512  * Remove a token type from the token type anchor set (a multi-set).
 513  */
 514 static void rem_anchor_token(token_kind_t const token_kind)
 515 {
 516         assert(token_kind < T_LAST_TOKEN);
 517         assert(token_anchor_set[token_kind] != 0);
 518         --token_anchor_set[token_kind];
 519 }
 520
 521 /**
 522  * Eat tokens until a matching token type is found.
 523  */
 524 static void eat_until_matching_token(token_kind_t const type)
 525 {
 526         token_kind_t end_token;
 527         switch (type) {
 528                 case '(': end_token = ')';  break;
 529                 case '{': end_token = '}';  break;
 530                 case '[': end_token = ']';  break;
 531                 default:  end_token = type; break;
 532         }
 533
 534         unsigned parenthesis_count = 0;
 535         unsigned brace_count       = 0;
 536         unsigned bracket_count     = 0;
 537         while (token.kind        != end_token ||
 538                parenthesis_count != 0         ||
 539                brace_count       != 0         ||
 540                bracket_count     != 0) {
 541                 switch (token.kind) {
 542                 case T_EOF: return;
 543                 case '(': ++parenthesis_count; break;
 544                 case '{': ++brace_count;       break;
 545                 case '[': ++bracket_count;     break;
 546
 547                 case ')':
 548                         if (parenthesis_count > 0)
 549                                 --parenthesis_count;
 550                         goto check_stop;
 551
 552                 case '}':
 553                         if (brace_count > 0)
 554                                 --brace_count;
 555                         goto check_stop;
 556
 557                 case ']':
 558                         if (bracket_count > 0)
 559                                 --bracket_count;
 560 check_stop:
 561                         if (token.kind        == end_token &&
 562                             parenthesis_count == 0         &&
 563                             brace_count       == 0         &&
 564                             bracket_count     == 0)
 565                                 return;
 566                         break;
 567
 568                 default:
 569                         break;
 570                 }
 571                 next_token();
 572         }
 573 }
 574
 575 /**
 576  * Eat input tokens until an anchor is found.
 577  */
 578 static void eat_until_anchor(void)
 579 {
 580         while (token_anchor_set[token.kind] == 0) {
 581                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
 582                         eat_until_matching_token(token.kind);
 583                 next_token();
 584         }
 585 }
 586
 587 /**
 588  * Eat a whole block from input tokens.
 589  */
 590 static void eat_block(void)
 591 {
 592         eat_until_matching_token('{');
 593         accept('}');
 594 }
 595
 596 /**
 597  * Report a parse error because an expected token was not found.
 598  */
 599 static
 600 #if defined __GNUC__ && __GNUC__ >= 4
 601 __attribute__((sentinel))
 602 #endif
 603 void parse_error_expected(const char *message, ...)
 604 {
 605         if (message != NULL) {
 606                 errorf(HERE, "%s", message);
 607         }
 608         va_list ap;
 609         va_start(ap, message);
 610         errorf(HERE, "got %K, expected %#k", &token, &ap, ", ");
 611         va_end(ap);
 612 }
 613
 614 /**
 615  * Report an incompatible type.
 616  */
 617 static void type_error_incompatible(const char *msg,
 618                 const position_t *pos, type_t *type1, type_t *type2)
 619 {
 620         errorf(pos, "%s, incompatible types: '%T' - '%T'", msg, type1, type2);
 621 }
 622
 623 static bool skip_till(token_kind_t const expected, char const *const context)
 624 {
 625         if (UNLIKELY(token.kind != expected)) {
 626                 parse_error_expected(context, expected, NULL);
 627                 add_anchor_token(expected);
 628                 eat_until_anchor();
 629                 rem_anchor_token(expected);
 630                 if (token.kind != expected)
 631                         return false;
 632         }
 633         return true;
 634 }
 635
 636 /**
 637  * Expect the current token is the expected token.
 638  * If not, generate an error and skip until the next anchor.
 639  */
 640 static void expect(token_kind_t const expected)
 641 {
 642         if (skip_till(expected, NULL))
 643                 eat(expected);
 644 }
 645
 646 static symbol_t *expect_identifier(char const *const context,
 647                                    position_t *const pos)
 648 {
 649         if (!skip_till(T_IDENTIFIER, context))
 650                 return NULL;
 651         symbol_t *const sym = token.base.symbol;
 652         if (pos)
 653                 *pos = *HERE;
 654         eat(T_IDENTIFIER);
 655         return sym;
 656 }
 657
 658 /**
 659  * Push a given scope on the scope stack and make it the
 660  * current scope
 661  */
 662 static scope_t *scope_push(scope_t *new_scope)
 663 {
 664         if (current_scope != NULL) {
 665                 new_scope->depth = current_scope->depth + 1;
 666         }
 667
 668         scope_t *old_scope = current_scope;
 669         current_scope      = new_scope;
 670         return old_scope;
 671 }
 672
 673 /**
 674  * Pop the current scope from the scope stack.
 675  */
 676 static void scope_pop(scope_t *old_scope)
 677 {
 678         current_scope = old_scope;
 679 }
 680
 681 /**
 682  * Search an entity by its symbol in a given namespace.
 683  */
 684 static entity_t *get_entity(const symbol_t *const symbol,
 685                             namespace_tag_t namespc)
 686 {
 687         entity_t *entity = symbol->entity;
 688         for (; entity != NULL; entity = entity->base.symbol_next) {
 689                 if ((namespace_tag_t)entity->base.namespc == namespc)
 690                         return entity;
 691         }
 692
 693         return NULL;
 694 }
 695
 696 /* §6.2.3:1 24)  There is only one name space for tags even though three are
 697  * possible. */
 698 static entity_t *get_tag(symbol_t const *const symbol,
 699                          entity_kind_tag_t const kind)
 700 {
 701         entity_t *entity = get_entity(symbol, NAMESPACE_TAG);
 702         if (entity != NULL && (entity_kind_tag_t)entity->kind != kind) {
 703                 errorf(HERE,
 704                                 "'%Y' defined as wrong kind of tag (previous definition %P)",
 705                                 symbol, &entity->base.pos);
 706                 entity = NULL;
 707         }
 708         return entity;
 709 }
 710
 711 /**
 712  * pushs an entity on the environment stack and links the corresponding symbol
 713  * it.
 714  */
 715 static void stack_push(stack_entry_t **stack_ptr, entity_t *entity)
 716 {
 717         symbol_t           *symbol  = entity->base.symbol;
 718         entity_namespace_t  namespc = entity->base.namespc;
 719         assert(namespc != 0);
 720
 721         /* replace/add entity into entity list of the symbol */
 722         entity_t **anchor;
 723         entity_t  *iter;
 724         for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 725                 iter = *anchor;
 726                 if (iter == NULL)
 727                         break;
 728
 729                 /* replace an entry? */
 730                 if (iter->base.namespc == namespc) {
 731                         entity->base.symbol_next = iter->base.symbol_next;
 732                         break;
 733                 }
 734         }
 735         *anchor = entity;
 736
 737         /* remember old declaration */
 738         stack_entry_t entry;
 739         entry.symbol     = symbol;
 740         entry.old_entity = iter;
 741         entry.namespc    = namespc;
 742         ARR_APP1(stack_entry_t, *stack_ptr, entry);
 743 }
 744
 745 /**
 746  * Push an entity on the environment stack.
 747  */
 748 static void environment_push(entity_t *entity)
 749 {
 750         assert(entity->base.pos.input_name != NULL);
 751         assert(entity->base.parent_scope != NULL);
 752         stack_push(&environment_stack, entity);
 753 }
 754
 755 /**
 756  * Push a declaration on the global label stack.
 757  *
 758  * @param declaration  the declaration
 759  */
 760 static void label_push(entity_t *label)
 761 {
 762         /* we abuse the parameters scope as parent for the labels */
 763         label->base.parent_scope = &current_function->parameters;
 764         stack_push(&label_stack, label);
 765 }
 766
 767 /**
 768  * pops symbols from the environment stack until @p new_top is the top element
 769  */
 770 static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 771 {
 772         stack_entry_t *stack = *stack_ptr;
 773         size_t         top   = ARR_LEN(stack);
 774         size_t         i;
 775
 776         assert(new_top <= top);
 777         if (new_top == top)
 778                 return;
 779
 780         for (i = top; i > new_top; --i) {
 781                 stack_entry_t *entry = &stack[i - 1];
 782
 783                 entity_t           *old_entity = entry->old_entity;
 784                 symbol_t           *symbol     = entry->symbol;
 785                 entity_namespace_t  namespc    = entry->namespc;
 786
 787                 /* replace with old_entity/remove */
 788                 entity_t **anchor;
 789                 entity_t  *iter;
 790                 for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 791                         iter = *anchor;
 792                         assert(iter != NULL);
 793                         /* replace an entry? */
 794                         if (iter->base.namespc == namespc)
 795                                 break;
 796                 }
 797
 798                 /* restore definition from outer scopes (if there was one) */
 799                 if (old_entity != NULL) {
 800                         old_entity->base.symbol_next = iter->base.symbol_next;
 801                         *anchor                      = old_entity;
 802                 } else {
 803                         /* remove entry from list */
 804                         *anchor = iter->base.symbol_next;
 805                 }
 806         }
 807
 808         ARR_SHRINKLEN(*stack_ptr, new_top);
 809 }
 810
 811 /**
 812  * Pop all entries from the environment stack until the new_top
 813  * is reached.
 814  *
 815  * @param new_top  the new stack top
 816  */
 817 static void environment_pop_to(size_t new_top)
 818 {
 819         stack_pop_to(&environment_stack, new_top);
 820 }
 821
 822 /**
 823  * Pop all entries from the global label stack until the new_top
 824  * is reached.
 825  *
 826  * @param new_top  the new stack top
 827  */
 828 static void label_pop_to(size_t new_top)
 829 {
 830         stack_pop_to(&label_stack, new_top);
 831 }
 832
 833 /**
 834  * §6.3.1.1:2  Do integer promotion for a given type.
 835  *
 836  * @param type  the type to promote
 837  * @return the promoted type
 838  */
 839 static type_t *promote_integer(type_t *type)
 840 {
 841         atomic_type_kind_t akind = get_arithmetic_akind(type);
 842         if (get_akind_rank(akind) < get_akind_rank(ATOMIC_TYPE_INT))
 843                 type = type_int;
 844
 845         return type;
 846 }
 847
 848 /**
 849  * Check if a given expression represents a null pointer constant.
 850  *
 851  * @param expression  the expression to check
 852  */
 853 static bool is_null_pointer_constant(const expression_t *expression)
 854 {
 855         /* skip void* cast */
 856         if (expression->kind == EXPR_UNARY_CAST) {
 857                 type_t *const type = skip_typeref(expression->base.type);
 858                 if (type == type_void_ptr)
 859                         expression = expression->unary.value;
 860         }
 861
 862         switch (is_constant_expression(expression)) {
 863                 case EXPR_CLASS_VARIABLE:         return false;
 864                 case EXPR_CLASS_ERROR:            return true;
 865                 case EXPR_CLASS_CONSTANT:         return false;
 866                 case EXPR_CLASS_INTEGER_CONSTANT: return !fold_constant_to_bool(expression);
 867         }
 868         panic("invalid expression classification");
 869 }
 870
 871 /**
 872  * Create an implicit cast expression.
 873  *
 874  * @param expression  the expression to cast
 875  * @param dest_type   the destination type
 876  */
 877 static expression_t *create_implicit_cast(expression_t *expression,
 878                                           type_t *dest_type)
 879 {
 880         type_t *const source_type = skip_typeref(expression->base.type);
 881         if (source_type == skip_typeref(dest_type))
 882                 return expression;
 883
 884         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
 885         cast->unary.value   = expression;
 886         cast->base.type     = dest_type;
 887         cast->base.implicit = true;
 888
 889         return cast;
 890 }
 891
 892 typedef enum assign_error_t {
 893         ASSIGN_SUCCESS,
 894         ASSIGN_ERROR_INCOMPATIBLE,
 895         ASSIGN_ERROR_POINTER_QUALIFIER_MISSING,
 896         ASSIGN_WARNING_POINTER_INCOMPATIBLE,
 897         ASSIGN_WARNING_POINTER_FROM_INT,
 898         ASSIGN_WARNING_INT_FROM_POINTER
 899 } assign_error_t;
 900
 901 static void report_assign_error(assign_error_t error, type_t *orig_type_left, expression_t const *const right, char const *const context, position_t const *const pos)
 902 {
 903         type_t *const orig_type_right = right->base.type;
 904         type_t *const type_left       = skip_typeref(orig_type_left);
 905         type_t *const type_right      = skip_typeref(orig_type_right);
 906
 907         switch (error) {
 908         case ASSIGN_SUCCESS:
 909                 return;
 910         case ASSIGN_ERROR_INCOMPATIBLE:
 911                 errorf(pos, "destination type '%T' in %s is incompatible with type '%T'", orig_type_left, context, orig_type_right);
 912                 return;
 913
 914         case ASSIGN_ERROR_POINTER_QUALIFIER_MISSING: {
 915                 type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
 916                 type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 917
 918                 /* the left type has all qualifiers from the right type */
 919                 unsigned missing_qualifiers = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 920                 warningf(WARN_OTHER, pos, "destination type '%T' in %s from type '%T' lacks qualifiers '%Q' in pointer target type", orig_type_left, context, orig_type_right, missing_qualifiers);
 921                 return;
 922         }
 923
 924         case ASSIGN_WARNING_POINTER_INCOMPATIBLE:
 925                 warningf(WARN_OTHER, pos, "destination type '%T' in %s is incompatible with '%E' of type '%T'", orig_type_left, context, right, orig_type_right);
 926                 return;
 927
 928         case ASSIGN_WARNING_POINTER_FROM_INT:
 929                 warningf(WARN_OTHER, pos, "%s makes pointer '%T' from integer '%T' without a cast", context, orig_type_left, orig_type_right);
 930                 return;
 931
 932         case ASSIGN_WARNING_INT_FROM_POINTER:
 933                 warningf(WARN_OTHER, pos, "%s makes integer '%T' from pointer '%T' without a cast", context, orig_type_left, orig_type_right);
 934                 return;
 935
 936         default:
 937                 panic("invalid error value");
 938         }
 939 }
 940
 941 /** Implements the rules from §6.5.16.1 */
 942 static assign_error_t semantic_assign(type_t *orig_type_left,
 943                                       const expression_t *const right)
 944 {
 945         type_t *const orig_type_right = right->base.type;
 946         type_t *const type_left       = skip_typeref(orig_type_left);
 947         type_t *const type_right      = skip_typeref(orig_type_right);
 948
 949         if (is_type_pointer(type_left)) {
 950                 if (is_null_pointer_constant(right)) {
 951                         return ASSIGN_SUCCESS;
 952                 } else if (is_type_pointer(type_right)) {
 953                         type_t *points_to_left
 954                                 = skip_typeref(type_left->pointer.points_to);
 955                         type_t *points_to_right
 956                                 = skip_typeref(type_right->pointer.points_to);
 957                         assign_error_t res = ASSIGN_SUCCESS;
 958
 959                         /* the left type has all qualifiers from the right type */
 960                         unsigned missing_qualifiers
 961                                 = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 962                         if (missing_qualifiers != 0) {
 963                                 res = ASSIGN_ERROR_POINTER_QUALIFIER_MISSING;
 964                         }
 965
 966                         points_to_left  = get_unqualified_type(points_to_left);
 967                         points_to_right = get_unqualified_type(points_to_right);
 968
 969                         if (is_type_void(points_to_left))
 970                                 return res;
 971
 972                         if (is_type_void(points_to_right)) {
 973                                 /* ISO/IEC 14882:1998(E) §C.1.2:6 */
 974                                 return c_mode & _CXX ? ASSIGN_ERROR_INCOMPATIBLE : res;
 975                         }
 976
 977                         if (!types_compatible(points_to_left, points_to_right)) {
 978                                 return ASSIGN_WARNING_POINTER_INCOMPATIBLE;
 979                         }
 980
 981                         return res;
 982                 } else if (is_type_integer(type_right)) {
 983                         return ASSIGN_WARNING_POINTER_FROM_INT;
 984                 }
 985         } else if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
 986                         (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
 987                                 && is_type_pointer(type_right))) {
 988                 return ASSIGN_SUCCESS;
 989         } else if (is_type_compound(type_left) && is_type_compound(type_right)) {
 990                 type_t *const unqual_type_left  = get_unqualified_type(type_left);
 991                 type_t *const unqual_type_right = get_unqualified_type(type_right);
 992                 if (types_compatible(unqual_type_left, unqual_type_right)) {
 993                         return ASSIGN_SUCCESS;
 994                 }
 995         } else if (is_type_integer(type_left) && is_type_pointer(type_right)) {
 996                 return ASSIGN_WARNING_INT_FROM_POINTER;
 997         }
 998
 999         if (!is_type_valid(type_left) || !is_type_valid(type_right))
1000                 return ASSIGN_SUCCESS;
1001
1002         return ASSIGN_ERROR_INCOMPATIBLE;
1003 }
1004
1005 static expression_t *parse_constant_expression(void)
1006 {
1007         expression_t *result = parse_subexpression(PREC_CONDITIONAL);
1008
1009         if (is_constant_expression(result) == EXPR_CLASS_VARIABLE) {
1010                 errorf(&result->base.pos, "expression '%E' is not constant", result);
1011         }
1012
1013         return result;
1014 }
1015
1016 static expression_t *parse_assignment_expression(void)
1017 {
1018         return parse_subexpression(PREC_ASSIGNMENT);
1019 }
1020
1021 static void append_string(string_t const *const s)
1022 {
1023         /* FIXME Using the ast_obstack is a hack.  Using the symbol_obstack is not
1024          * possible, because other tokens are grown there alongside. */
1025         obstack_grow(&ast_obstack, s->begin, s->size);
1026 }
1027
1028 static string_t finish_string(string_encoding_t const enc)
1029 {
1030         obstack_1grow(&ast_obstack, '\0');
1031         size_t      const size   = obstack_object_size(&ast_obstack) - 1;
1032         char const *const string = obstack_finish(&ast_obstack);
1033         return (string_t){ string, size, enc };
1034 }
1035
1036 static string_t concat_string_literals(void)
1037 {
1038         assert(token.kind == T_STRING_LITERAL);
1039
1040         string_t result;
1041         if (look_ahead(1)->kind == T_STRING_LITERAL) {
1042                 append_string(&token.literal.string);
1043                 eat(T_STRING_LITERAL);
1044                 warningf(WARN_TRADITIONAL, HERE, "traditional C rejects string constant concatenation");
1045                 string_encoding_t enc = token.literal.string.encoding;
1046                 do {
1047                         string_encoding_t const new_enc = token.literal.string.encoding;
1048                         if (new_enc != enc && new_enc != STRING_ENCODING_CHAR) {
1049                                 if (enc == STRING_ENCODING_CHAR) {
1050                                         enc = new_enc;
1051                                 } else {
1052                                         errorf(HERE, "concatenating string literals with encodings %s and %s", get_string_encoding_prefix(enc), get_string_encoding_prefix(new_enc));
1053                                 }
1054                         }
1055                         append_string(&token.literal.string);
1056                         eat(T_STRING_LITERAL);
1057                 } while (token.kind == T_STRING_LITERAL);
1058                 result = finish_string(enc);
1059         } else {
1060                 result = token.literal.string;
1061                 eat(T_STRING_LITERAL);
1062         }
1063
1064         return result;
1065 }
1066
1067 static string_t parse_string_literals(char const *const context)
1068 {
1069         if (!skip_till(T_STRING_LITERAL, context))
1070                 return (string_t){ "", 0, STRING_ENCODING_CHAR };
1071
1072         position_t const pos = *HERE;
1073         string_t   const res = concat_string_literals();
1074
1075         if (res.encoding != STRING_ENCODING_CHAR) {
1076                 errorf(&pos, "expected plain string literal, got %s string literal", get_string_encoding_prefix(res.encoding));
1077         }
1078
1079         return res;
1080 }
1081
1082 static attribute_t *allocate_attribute_zero(attribute_kind_t kind)
1083 {
1084         attribute_t *attribute = allocate_ast_zero(sizeof(*attribute));
1085         attribute->kind = kind;
1086         attribute->pos  = *HERE;
1087         return attribute;
1088 }
1089
1090 /**
1091  * Parse (gcc) attribute argument. From gcc comments in gcc source:
1092  *
1093  *  attribute:
1094  *    __attribute__ ( ( attribute-list ) )
1095  *
1096  *  attribute-list:
1097  *    attrib
1098  *    attribute_list , attrib
1099  *
1100  *  attrib:
1101  *    empty
1102  *    any-word
1103  *    any-word ( identifier )
1104  *    any-word ( identifier , nonempty-expr-list )
1105  *    any-word ( expr-list )
1106  *
1107  *  where the "identifier" must not be declared as a type, and
1108  *  "any-word" may be any identifier (including one declared as a
1109  *  type), a reserved word storage class specifier, type specifier or
1110  *  type qualifier.  ??? This still leaves out most reserved keywords
1111  *  (following the old parser), shouldn't we include them, and why not
1112  *  allow identifiers declared as types to start the arguments?
1113  *
1114  *  Matze: this all looks confusing and little systematic, so we're even less
1115  *  strict and parse any list of things which are identifiers or
1116  *  (assignment-)expressions.
1117  */
1118 static attribute_argument_t *parse_attribute_arguments(void)
1119 {
1120         attribute_argument_t  *first  = NULL;
1121         attribute_argument_t **anchor = &first;
1122         if (token.kind != ')') do {
1123                 attribute_argument_t *argument = allocate_ast_zero(sizeof(*argument));
1124
1125                 /* is it an identifier */
1126                 if (token.kind == T_IDENTIFIER
1127                                 && (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
1128                         argument->kind     = ATTRIBUTE_ARGUMENT_SYMBOL;
1129                         argument->v.symbol = token.base.symbol;
1130                         eat(T_IDENTIFIER);
1131                 } else {
1132                         /* must be an expression */
1133                         expression_t *expression = parse_assignment_expression();
1134
1135                         argument->kind         = ATTRIBUTE_ARGUMENT_EXPRESSION;
1136                         argument->v.expression = expression;
1137                 }
1138
1139                 /* append argument */
1140                 *anchor = argument;
1141                 anchor  = &argument->next;
1142         } while (accept(','));
1143         expect(')');
1144         return first;
1145 }
1146
1147 static attribute_t *parse_attribute_asm(void)
1148 {
1149         attribute_t *attribute = allocate_attribute_zero(ATTRIBUTE_GNU_ASM);
1150         eat(T_asm);
1151         expect('(');
1152         attribute->a.arguments = parse_attribute_arguments();
1153         return attribute;
1154 }
1155
1156 static attribute_t *parse_attribute_gnu_single(void)
1157 {
1158         /* parse "any-word" */
1159         symbol_t *const symbol = token.base.symbol;
1160         if (symbol == NULL) {
1161                 parse_error_expected("while parsing attribute((", T_IDENTIFIER, NULL);
1162                 return NULL;
1163         }
1164
1165         attribute_kind_t  kind;
1166         char const *const name = symbol->string;
1167         for (kind = ATTRIBUTE_GNU_FIRST;; ++kind) {
1168                 if (kind > ATTRIBUTE_GNU_LAST) {
1169                         /* special case for "__const" */
1170                         if (token.kind == T_const) {
1171                                 kind = ATTRIBUTE_GNU_CONST;
1172                                 break;
1173                         }
1174
1175                         warningf(WARN_ATTRIBUTE, HERE, "unknown attribute '%s' ignored", name);
1176                         /* TODO: we should still save the attribute in the list... */
1177                         kind = ATTRIBUTE_UNKNOWN;
1178                         break;
1179                 }
1180
1181                 const char *attribute_name = get_attribute_name(kind);
1182                 if (attribute_name != NULL && streq_underscore(attribute_name, name))
1183                         break;
1184         }
1185
1186         attribute_t *attribute = allocate_attribute_zero(kind);
1187         next_token();
1188
1189         /* parse arguments */
1190         if (accept('('))
1191                 attribute->a.arguments = parse_attribute_arguments();
1192
1193         return attribute;
1194 }
1195
1196 static attribute_t *parse_attribute_gnu(void)
1197 {
1198         attribute_t  *first  = NULL;
1199         attribute_t **anchor = &first;
1200
1201         eat(T___attribute__);
1202         add_anchor_token(')');
1203         add_anchor_token(',');
1204         expect('(');
1205         expect('(');
1206
1207         if (token.kind != ')') do {
1208                 attribute_t *attribute = parse_attribute_gnu_single();
1209                 if (attribute) {
1210                         *anchor = attribute;
1211                         anchor  = &attribute->next;
1212                 }
1213         } while (accept(','));
1214         rem_anchor_token(',');
1215         rem_anchor_token(')');
1216
1217         expect(')');
1218         expect(')');
1219         return first;
1220 }
1221
1222 /** Parse attributes. */
1223 static attribute_t *parse_attributes(attribute_t *first)
1224 {
1225         attribute_t **anchor = &first;
1226         for (;;) {
1227                 while (*anchor != NULL)
1228                         anchor = &(*anchor)->next;
1229
1230                 attribute_t *attribute;
1231                 switch (token.kind) {
1232                 case T___attribute__:
1233                         attribute = parse_attribute_gnu();
1234                         if (attribute == NULL)
1235                                 continue;
1236                         break;
1237
1238                 case T_asm:
1239                         attribute = parse_attribute_asm();
1240                         break;
1241
1242                 case T_cdecl:
1243                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_CDECL);
1244                         eat(T_cdecl);
1245                         break;
1246
1247                 case T__fastcall:
1248                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FASTCALL);
1249                         eat(T__fastcall);
1250                         break;
1251
1252                 case T__forceinline:
1253                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FORCEINLINE);
1254                         eat(T__forceinline);
1255                         break;
1256
1257                 case T__stdcall:
1258                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_STDCALL);
1259                         eat(T__stdcall);
1260                         break;
1261
1262                 case T___thiscall:
1263                         /* TODO record modifier */
1264                         warningf(WARN_OTHER, HERE, "Ignoring declaration modifier %K", &token);
1265                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_THISCALL);
1266                         eat(T___thiscall);
1267                         break;
1268
1269                 default:
1270                         return first;
1271                 }
1272
1273                 *anchor = attribute;
1274                 anchor  = &attribute->next;
1275         }
1276 }
1277
1278 static void mark_vars_read(expression_t *expr, entity_t *lhs_ent);
1279
1280 static entity_t *determine_lhs_ent(expression_t *const expr,
1281                                    entity_t *lhs_ent)
1282 {
1283         switch (expr->kind) {
1284                 case EXPR_REFERENCE: {
1285                         entity_t *const entity = expr->reference.entity;
1286                         /* we should only find variables as lvalues... */
1287                         if (entity->base.kind != ENTITY_VARIABLE
1288                                         && entity->base.kind != ENTITY_PARAMETER)
1289                                 return NULL;
1290
1291                         return entity;
1292                 }
1293
1294                 case EXPR_ARRAY_ACCESS: {
1295                         expression_t *const ref = expr->array_access.array_ref;
1296                         entity_t     *      ent = NULL;
1297                         if (is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1298                                 ent     = determine_lhs_ent(ref, lhs_ent);
1299                                 lhs_ent = ent;
1300                         } else {
1301                                 mark_vars_read(ref, lhs_ent);
1302                         }
1303                         mark_vars_read(expr->array_access.index, lhs_ent);
1304                         return ent;
1305                 }
1306
1307                 case EXPR_SELECT: {
1308                         mark_vars_read(expr->select.compound, lhs_ent);
1309                         if (is_type_compound(skip_typeref(expr->base.type)))
1310                                 return determine_lhs_ent(expr->select.compound, lhs_ent);
1311                         return NULL;
1312                 }
1313
1314                 case EXPR_UNARY_DEREFERENCE: {
1315                         expression_t *const val = expr->unary.value;
1316                         if (val->kind == EXPR_UNARY_TAKE_ADDRESS) {
1317                                 /* *&x is a NOP */
1318                                 return determine_lhs_ent(val->unary.value, lhs_ent);
1319                         } else {
1320                                 mark_vars_read(val, NULL);
1321                                 return NULL;
1322                         }
1323                 }
1324
1325                 default:
1326                         mark_vars_read(expr, NULL);
1327                         return NULL;
1328         }
1329 }
1330
1331 #define ENT_ANY ((entity_t*)-1)
1332
1333 /**
1334  * Mark declarations, which are read.  This is used to detect variables, which
1335  * are never read.
1336  * Example:
1337  * x = x + 1;
1338  *   x is not marked as "read", because it is only read to calculate its own new
1339  *   value.
1340  *
1341  * x += y; y += x;
1342  *   x and y are not detected as "not read", because multiple variables are
1343  *   involved.
1344  */
1345 static void mark_vars_read(expression_t *const expr, entity_t *lhs_ent)
1346 {
1347         switch (expr->kind) {
1348                 case EXPR_REFERENCE: {
1349                         entity_t *const entity = expr->reference.entity;
1350                         if (entity->kind != ENTITY_VARIABLE
1351                                         && entity->kind != ENTITY_PARAMETER)
1352                                 return;
1353
1354                         if (lhs_ent != entity && lhs_ent != ENT_ANY) {
1355                                 entity->variable.read = true;
1356                         }
1357                         return;
1358                 }
1359
1360                 case EXPR_CALL:
1361                         // TODO respect pure/const
1362                         mark_vars_read(expr->call.function, NULL);
1363                         for (call_argument_t *arg = expr->call.arguments; arg != NULL; arg = arg->next) {
1364                                 mark_vars_read(arg->expression, NULL);
1365                         }
1366                         return;
1367
1368                 case EXPR_CONDITIONAL:
1369                         // TODO lhs_decl should depend on whether true/false have an effect
1370                         mark_vars_read(expr->conditional.condition, NULL);
1371                         if (expr->conditional.true_expression != NULL)
1372                                 mark_vars_read(expr->conditional.true_expression, lhs_ent);
1373                         mark_vars_read(expr->conditional.false_expression, lhs_ent);
1374                         return;
1375
1376                 case EXPR_SELECT:
1377                         if (lhs_ent == ENT_ANY
1378                                         && !is_type_compound(skip_typeref(expr->base.type)))
1379                                 lhs_ent = NULL;
1380                         mark_vars_read(expr->select.compound, lhs_ent);
1381                         return;
1382
1383                 case EXPR_ARRAY_ACCESS: {
1384                         mark_vars_read(expr->array_access.index, lhs_ent);
1385                         expression_t *const ref = expr->array_access.array_ref;
1386                         if (!is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1387                                 if (lhs_ent == ENT_ANY)
1388                                         lhs_ent = NULL;
1389                         }
1390                         mark_vars_read(ref, lhs_ent);
1391                         return;
1392                 }
1393
1394                 case EXPR_VA_ARG:
1395                         mark_vars_read(expr->va_arge.ap, lhs_ent);
1396                         return;
1397
1398                 case EXPR_VA_COPY:
1399                         mark_vars_read(expr->va_copye.src, lhs_ent);
1400                         return;
1401
1402                 case EXPR_UNARY_CAST:
1403                         /* Special case: Use void cast to mark a variable as "read" */
1404                         if (is_type_void(skip_typeref(expr->base.type)))
1405                                 lhs_ent = NULL;
1406                         goto unary;
1407
1408
1409                 case EXPR_UNARY_THROW:
1410                         if (expr->unary.value == NULL)
1411                                 return;
1412                         /* FALLTHROUGH */
1413                 case EXPR_UNARY_DEREFERENCE:
1414                 case EXPR_UNARY_DELETE:
1415                 case EXPR_UNARY_DELETE_ARRAY:
1416                         if (lhs_ent == ENT_ANY)
1417                                 lhs_ent = NULL;
1418                         goto unary;
1419
1420                 case EXPR_UNARY_NEGATE:
1421                 case EXPR_UNARY_PLUS:
1422                 case EXPR_UNARY_COMPLEMENT:
1423                 case EXPR_UNARY_NOT:
1424                 case EXPR_UNARY_TAKE_ADDRESS:
1425                 case EXPR_UNARY_POSTFIX_INCREMENT:
1426                 case EXPR_UNARY_POSTFIX_DECREMENT:
1427                 case EXPR_UNARY_PREFIX_INCREMENT:
1428                 case EXPR_UNARY_PREFIX_DECREMENT:
1429                 case EXPR_UNARY_ASSUME:
1430                 case EXPR_UNARY_IMAG:
1431                 case EXPR_UNARY_REAL:
1432 unary:
1433                         mark_vars_read(expr->unary.value, lhs_ent);
1434                         return;
1435
1436                 case EXPR_BINARY_ADD:
1437                 case EXPR_BINARY_SUB:
1438                 case EXPR_BINARY_MUL:
1439                 case EXPR_BINARY_DIV:
1440                 case EXPR_BINARY_MOD:
1441                 case EXPR_BINARY_EQUAL:
1442                 case EXPR_BINARY_NOTEQUAL:
1443                 case EXPR_BINARY_LESS:
1444                 case EXPR_BINARY_LESSEQUAL:
1445                 case EXPR_BINARY_GREATER:
1446                 case EXPR_BINARY_GREATEREQUAL:
1447                 case EXPR_BINARY_BITWISE_AND:
1448                 case EXPR_BINARY_BITWISE_OR:
1449                 case EXPR_BINARY_BITWISE_XOR:
1450                 case EXPR_BINARY_LOGICAL_AND:
1451                 case EXPR_BINARY_LOGICAL_OR:
1452                 case EXPR_BINARY_SHIFTLEFT:
1453                 case EXPR_BINARY_SHIFTRIGHT:
1454                 case EXPR_BINARY_COMMA:
1455                 case EXPR_BINARY_ISGREATER:
1456                 case EXPR_BINARY_ISGREATEREQUAL:
1457                 case EXPR_BINARY_ISLESS:
1458                 case EXPR_BINARY_ISLESSEQUAL:
1459                 case EXPR_BINARY_ISLESSGREATER:
1460                 case EXPR_BINARY_ISUNORDERED:
1461                         mark_vars_read(expr->binary.left,  lhs_ent);
1462                         mark_vars_read(expr->binary.right, lhs_ent);
1463                         return;
1464
1465                 case EXPR_BINARY_ASSIGN:
1466                 case EXPR_BINARY_MUL_ASSIGN:
1467                 case EXPR_BINARY_DIV_ASSIGN:
1468                 case EXPR_BINARY_MOD_ASSIGN:
1469                 case EXPR_BINARY_ADD_ASSIGN:
1470                 case EXPR_BINARY_SUB_ASSIGN:
1471                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:
1472                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:
1473                 case EXPR_BINARY_BITWISE_AND_ASSIGN:
1474                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:
1475                 case EXPR_BINARY_BITWISE_OR_ASSIGN: {
1476                         if (lhs_ent == ENT_ANY)
1477                                 lhs_ent = NULL;
1478                         lhs_ent = determine_lhs_ent(expr->binary.left, lhs_ent);
1479                         mark_vars_read(expr->binary.right, lhs_ent);
1480                         return;
1481                 }
1482
1483                 case EXPR_VA_START:
1484                         determine_lhs_ent(expr->va_starte.ap, lhs_ent);
1485                         return;
1486
1487                 case EXPR_LITERAL_CASES:
1488                 case EXPR_LITERAL_CHARACTER:
1489                 case EXPR_ERROR:
1490                 case EXPR_STRING_LITERAL:
1491                 case EXPR_COMPOUND_LITERAL: // TODO init?
1492                 case EXPR_SIZEOF:
1493                 case EXPR_CLASSIFY_TYPE:
1494                 case EXPR_ALIGNOF:
1495                 case EXPR_FUNCNAME:
1496                 case EXPR_BUILTIN_CONSTANT_P:
1497                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
1498                 case EXPR_OFFSETOF:
1499                 case EXPR_STATEMENT: // TODO
1500                 case EXPR_LABEL_ADDRESS:
1501                 case EXPR_ENUM_CONSTANT:
1502                         return;
1503         }
1504
1505         panic("unhandled expression");
1506 }
1507
1508 static designator_t *parse_designation(void)
1509 {
1510         designator_t  *result = NULL;
1511         designator_t **anchor = &result;
1512
1513         for (;;) {
1514                 designator_t *designator;
1515                 switch (token.kind) {
1516                 case '[':
1517                         designator      = allocate_ast_zero(sizeof(designator[0]));
1518                         designator->pos = *HERE;
1519                         eat('[');
1520                         add_anchor_token(']');
1521                         add_anchor_token(T_DOTDOTDOT);
1522                         designator->array_index = parse_constant_expression();
1523                         if (accept(T_DOTDOTDOT)) {
1524                                 designator->range_last = parse_constant_expression();
1525                                 errorf(&designator->pos, "range initializer not supported");
1526                         }
1527                         rem_anchor_token(T_DOTDOTDOT);
1528                         rem_anchor_token(']');
1529                         expect(']');
1530                         break;
1531                 case '.':
1532                         designator      = allocate_ast_zero(sizeof(designator[0]));
1533                         designator->pos = *HERE;
1534                         eat('.');
1535                         designator->symbol = expect_identifier("while parsing designator", NULL);
1536                         if (!designator->symbol)
1537                                 return NULL;
1538                         break;
1539                 default:
1540                         expect('=');
1541                         return result;
1542                 }
1543
1544                 assert(designator != NULL);
1545                 *anchor = designator;
1546                 anchor  = &designator->next;
1547         }
1548 }
1549
1550 /**
1551  * Build an initializer from a given expression.
1552  */
1553 static initializer_t *initializer_from_expression(type_t *orig_type,
1554                                                   expression_t *expression)
1555 {
1556         /* TODO check that expression is a constant expression */
1557
1558         type_t *const type = skip_typeref(orig_type);
1559
1560         /* §6.7.8.14/15 char array may be initialized by string literals */
1561         if (expression->kind == EXPR_STRING_LITERAL && is_type_array(type)) {
1562                 array_type_t *const array_type   = &type->array;
1563                 type_t       *const element_type = skip_typeref(array_type->element_type);
1564                 switch (expression->string_literal.value.encoding) {
1565                 case STRING_ENCODING_CHAR:
1566                 case STRING_ENCODING_UTF8: {
1567                         if (is_type_atomic(element_type, ATOMIC_TYPE_CHAR)  ||
1568                             is_type_atomic(element_type, ATOMIC_TYPE_SCHAR) ||
1569                             is_type_atomic(element_type, ATOMIC_TYPE_UCHAR)) {
1570                                 goto make_string_init;
1571                         }
1572                         break;
1573                 }
1574
1575                 case STRING_ENCODING_CHAR16:
1576                 case STRING_ENCODING_CHAR32:
1577                 case STRING_ENCODING_WIDE: {
1578                         assert(is_type_pointer(expression->base.type));
1579                         type_t *const init_type = get_unqualified_type(expression->base.type->pointer.points_to);
1580                         if (types_compatible(get_unqualified_type(element_type), init_type)) {
1581 make_string_init:;
1582                                 initializer_t *const init = allocate_initializer_zero(INITIALIZER_STRING);
1583                                 init->value.value = expression;
1584                                 return init;
1585                         }
1586                         break;
1587                 }
1588                 }
1589         }
1590
1591         assign_error_t error = semantic_assign(type, expression);
1592         if (error == ASSIGN_ERROR_INCOMPATIBLE)
1593                 return NULL;
1594         report_assign_error(error, type, expression, "initializer",
1595                             &expression->base.pos);
1596
1597         initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
1598         result->value.value = create_implicit_cast(expression, type);
1599
1600         return result;
1601 }
1602
1603 /**
1604  * Parses an scalar initializer.
1605  *
1606  * §6.7.8.11; eat {} without warning
1607  */
1608 static initializer_t *parse_scalar_initializer(type_t *type,
1609                                                bool must_be_constant)
1610 {
1611         /* there might be extra {} hierarchies */
1612         int braces = 0;
1613         if (token.kind == '{') {
1614                 warningf(WARN_OTHER, HERE, "extra curly braces around scalar initializer");
1615                 do {
1616                         eat('{');
1617                         ++braces;
1618                 } while (token.kind == '{');
1619         }
1620
1621         expression_t *expression = parse_assignment_expression();
1622         mark_vars_read(expression, NULL);
1623         if (must_be_constant && !is_linker_constant(expression)) {
1624                 errorf(&expression->base.pos,
1625                        "initialisation expression '%E' is not constant",
1626                        expression);
1627         }
1628
1629         initializer_t *initializer = initializer_from_expression(type, expression);
1630
1631         if (initializer == NULL) {
1632                 errorf(&expression->base.pos,
1633                        "expression '%E' (type '%T') doesn't match expected type '%T'",
1634                        expression, expression->base.type, type);
1635                 /* TODO */
1636                 return NULL;
1637         }
1638
1639         bool additional_warning_displayed = false;
1640         while (braces > 0) {
1641                 accept(',');
1642                 if (token.kind != '}') {
1643                         if (!additional_warning_displayed) {
1644                                 warningf(WARN_OTHER, HERE, "additional elements in scalar initializer");
1645                                 additional_warning_displayed = true;
1646                         }
1647                 }
1648                 eat_block();
1649                 braces--;
1650         }
1651
1652         return initializer;
1653 }
1654
1655 /**
1656  * An entry in the type path.
1657  */
1658 typedef struct type_path_entry_t type_path_entry_t;
1659 struct type_path_entry_t {
1660         type_t *type;       /**< the upper top type. restored to path->top_tye if this entry is popped. */
1661         union {
1662                 size_t         index;          /**< For array types: the current index. */
1663                 declaration_t *compound_entry; /**< For compound types: the current declaration. */
1664         } v;
1665 };
1666
1667 /**
1668  * A type path expression a position inside compound or array types.
1669  */
1670 typedef struct type_path_t type_path_t;
1671 struct type_path_t {
1672         type_path_entry_t *path;         /**< An flexible array containing the current path. */
1673         type_t            *top_type;     /**< type of the element the path points */
1674         size_t             max_index;    /**< largest index in outermost array */
1675 };
1676
1677 /**
1678  * Prints a type path for debugging.
1679  */
1680 static __attribute__((unused)) void debug_print_type_path(
1681                 const type_path_t *path)
1682 {
1683         size_t len = ARR_LEN(path->path);
1684
1685         for (size_t i = 0; i < len; ++i) {
1686                 const type_path_entry_t *entry = & path->path[i];
1687
1688                 type_t *type = skip_typeref(entry->type);
1689                 if (is_type_compound(type)) {
1690                         /* in gcc mode structs can have no members */
1691                         if (entry->v.compound_entry == NULL) {
1692                                 assert(i == len-1);
1693                                 continue;
1694                         }
1695                         fprintf(stderr, ".%s",
1696                                 entry->v.compound_entry->base.symbol->string);
1697                 } else if (is_type_array(type)) {
1698                         fprintf(stderr, "[%u]", (unsigned) entry->v.index);
1699                 } else {
1700                         fprintf(stderr, "-INVALID-");
1701                 }
1702         }
1703         if (path->top_type != NULL) {
1704                 fprintf(stderr, "  (");
1705                 print_type(path->top_type);
1706                 fprintf(stderr, ")");
1707         }
1708 }
1709
1710 /**
1711  * Return the top type path entry, i.e. in a path
1712  * (type).a.b returns the b.
1713  */
1714 static type_path_entry_t *get_type_path_top(const type_path_t *path)
1715 {
1716         size_t len = ARR_LEN(path->path);
1717         assert(len > 0);
1718         return &path->path[len-1];
1719 }
1720
1721 /**
1722  * Enlarge the type path by an (empty) element.
1723  */
1724 static type_path_entry_t *append_to_type_path(type_path_t *path)
1725 {
1726         size_t len = ARR_LEN(path->path);
1727         ARR_RESIZE(type_path_entry_t, path->path, len+1);
1728
1729         type_path_entry_t *result = & path->path[len];
1730         memset(result, 0, sizeof(result[0]));
1731         return result;
1732 }
1733
1734 /**
1735  * Descending into a sub-type. Enter the scope of the current top_type.
1736  */
1737 static void descend_into_subtype(type_path_t *path)
1738 {
1739         type_t *orig_top_type = path->top_type;
1740         type_t *top_type      = skip_typeref(orig_top_type);
1741
1742         type_path_entry_t *top = append_to_type_path(path);
1743         top->type              = top_type;
1744
1745         if (is_type_compound(top_type)) {
1746                 compound_t *const compound = top_type->compound.compound;
1747                 entity_t   *const entry    = skip_unnamed_bitfields(compound->members.entities);
1748
1749                 if (entry != NULL) {
1750                         top->v.compound_entry = &entry->declaration;
1751                         path->top_type = entry->declaration.type;
1752                 } else {
1753                         path->top_type = NULL;
1754                 }
1755         } else if (is_type_array(top_type)) {
1756                 top->v.index   = 0;
1757                 path->top_type = top_type->array.element_type;
1758         } else {
1759                 assert(!is_type_valid(top_type));
1760         }
1761 }
1762
1763 /**
1764  * Pop an entry from the given type path, i.e. returning from
1765  * (type).a.b to (type).a
1766  */
1767 static void ascend_from_subtype(type_path_t *path)
1768 {
1769         type_path_entry_t *top = get_type_path_top(path);
1770
1771         path->top_type = top->type;
1772
1773         size_t len = ARR_LEN(path->path);
1774         ARR_RESIZE(type_path_entry_t, path->path, len-1);
1775 }
1776
1777 /**
1778  * Pop entries from the given type path until the given
1779  * path level is reached.
1780  */
1781 static void ascend_to(type_path_t *path, size_t top_path_level)
1782 {
1783         size_t len = ARR_LEN(path->path);
1784
1785         while (len > top_path_level) {
1786                 ascend_from_subtype(path);
1787                 len = ARR_LEN(path->path);
1788         }
1789 }
1790
1791 static bool walk_designator(type_path_t *path, const designator_t *designator,
1792                             bool used_in_offsetof)
1793 {
1794         for (; designator != NULL; designator = designator->next) {
1795                 type_path_entry_t *top       = get_type_path_top(path);
1796                 type_t            *orig_type = top->type;
1797
1798                 type_t *type = skip_typeref(orig_type);
1799
1800                 if (designator->symbol != NULL) {
1801                         symbol_t *symbol = designator->symbol;
1802                         if (!is_type_compound(type)) {
1803                                 if (is_type_valid(type)) {
1804                                         errorf(&designator->pos,
1805                                                "'.%Y' designator used for non-compound type '%T'",
1806                                                symbol, orig_type);
1807                                 }
1808
1809                                 top->type             = type_error_type;
1810                                 top->v.compound_entry = NULL;
1811                                 orig_type             = type_error_type;
1812                         } else {
1813                                 compound_t *compound = type->compound.compound;
1814                                 entity_t   *iter     = compound->members.entities;
1815                                 for (; iter != NULL; iter = iter->base.next) {
1816                                         if (iter->base.symbol == symbol) {
1817                                                 break;
1818                                         }
1819                                 }
1820                                 if (iter == NULL) {
1821                                         errorf(&designator->pos,
1822                                                "'%T' has no member named '%Y'", orig_type, symbol);
1823                                         return false;
1824                                 }
1825                                 assert(iter->kind == ENTITY_COMPOUND_MEMBER);
1826                                 if (used_in_offsetof && iter->compound_member.bitfield) {
1827                                         errorf(&designator->pos,
1828                                                    "offsetof designator '%Y' must not specify bitfield",
1829                                                    symbol);
1830                                         return false;
1831                                 }
1832
1833                                 top->type             = orig_type;
1834                                 top->v.compound_entry = &iter->declaration;
1835                                 orig_type             = iter->declaration.type;
1836                         }
1837                 } else {
1838                         expression_t *array_index = designator->array_index;
1839                         if (is_constant_expression(array_index) < EXPR_CLASS_CONSTANT)
1840                                 return true;
1841
1842                         if (!is_type_array(type)) {
1843                                 if (is_type_valid(type)) {
1844                                         errorf(&designator->pos,
1845                                                "[%E] designator used for non-array type '%T'",
1846                                                array_index, orig_type);
1847                                 }
1848                                 return false;
1849                         }
1850
1851                         long index = fold_constant_to_int(array_index);
1852                         if (!used_in_offsetof) {
1853                                 if (index < 0) {
1854                                         errorf(&designator->pos,
1855                                                "array index [%E] must be positive", array_index);
1856                                 } else if (type->array.size_constant) {
1857                                         long array_size = type->array.size;
1858                                         if (index >= array_size) {
1859                                                 errorf(&designator->pos,
1860                                                        "designator [%E] (%d) exceeds array size %d",
1861                                                        array_index, index, array_size);
1862                                         }
1863                                 }
1864                         }
1865
1866                         top->type    = orig_type;
1867                         top->v.index = (size_t) index;
1868                         orig_type    = type->array.element_type;
1869                 }
1870                 path->top_type = orig_type;
1871
1872                 if (designator->next != NULL) {
1873                         descend_into_subtype(path);
1874                 }
1875         }
1876         return true;
1877 }
1878
1879 static void advance_current_object(type_path_t *path, size_t top_path_level)
1880 {
1881         type_path_entry_t *top = get_type_path_top(path);
1882
1883         type_t *type = skip_typeref(top->type);
1884         if (is_type_union(type)) {
1885                 /* in unions only the first element is initialized */
1886                 top->v.compound_entry = NULL;
1887         } else if (is_type_struct(type)) {
1888                 declaration_t *entry = top->v.compound_entry;
1889
1890                 entity_t *const next_entity = skip_unnamed_bitfields(entry->base.next);
1891                 if (next_entity != NULL) {
1892                         assert(is_declaration(next_entity));
1893                         entry = &next_entity->declaration;
1894                 } else {
1895                         entry = NULL;
1896                 }
1897
1898                 top->v.compound_entry = entry;
1899                 if (entry != NULL) {
1900                         path->top_type = entry->type;
1901                         return;
1902                 }
1903         } else if (is_type_array(type)) {
1904                 assert(is_type_array(type));
1905
1906                 top->v.index++;
1907
1908                 if (!type->array.size_constant || top->v.index < type->array.size) {
1909                         return;
1910                 }
1911         } else {
1912                 assert(!is_type_valid(type));
1913                 return;
1914         }
1915
1916         /* we're past the last member of the current sub-aggregate, try if we
1917          * can ascend in the type hierarchy and continue with another subobject */
1918         size_t len = ARR_LEN(path->path);
1919
1920         if (len > top_path_level) {
1921                 ascend_from_subtype(path);
1922                 advance_current_object(path, top_path_level);
1923         } else {
1924                 path->top_type = NULL;
1925         }
1926 }
1927
1928 /**
1929  * skip any {...} blocks until a closing bracket is reached.
1930  */
1931 static void skip_initializers(void)
1932 {
1933         accept('{');
1934
1935         while (token.kind != '}') {
1936                 if (token.kind == T_EOF)
1937                         return;
1938                 if (token.kind == '{') {
1939                         eat_block();
1940                         continue;
1941                 }
1942                 next_token();
1943         }
1944 }
1945
1946 static initializer_t *create_empty_initializer(void)
1947 {
1948         static initializer_t empty_initializer
1949                 = { .list = { { INITIALIZER_LIST }, 0 } };
1950         return &empty_initializer;
1951 }
1952
1953 /**
1954  * Parse a part of an initialiser for a struct or union,
1955  */
1956 static initializer_t *parse_sub_initializer(type_path_t *path,
1957                 type_t *outer_type, size_t top_path_level,
1958                 parse_initializer_env_t *env)
1959 {
1960         if (token.kind == '}') {
1961                 /* empty initializer */
1962                 return create_empty_initializer();
1963         }
1964
1965         initializer_t *result = NULL;
1966
1967         type_t *orig_type = path->top_type;
1968         type_t *type      = NULL;
1969
1970         if (orig_type == NULL) {
1971                 /* We are initializing an empty compound. */
1972         } else {
1973                 type = skip_typeref(orig_type);
1974         }
1975
1976         initializer_t **initializers = NEW_ARR_F(initializer_t*, 0);
1977
1978         while (true) {
1979                 designator_t *designator = NULL;
1980                 if (token.kind == '.' || token.kind == '[') {
1981                         designator = parse_designation();
1982                         goto finish_designator;
1983                 } else if (token.kind == T_IDENTIFIER && look_ahead(1)->kind == ':') {
1984                         /* GNU-style designator ("identifier: value") */
1985                         designator         = allocate_ast_zero(sizeof(designator[0]));
1986                         designator->pos    = *HERE;
1987                         designator->symbol = token.base.symbol;
1988                         eat(T_IDENTIFIER);
1989                         eat(':');
1990
1991 finish_designator:
1992                         /* reset path to toplevel, evaluate designator from there */
1993                         ascend_to(path, top_path_level);
1994                         if (!walk_designator(path, designator, false)) {
1995                                 /* can't continue after designation error */
1996                                 goto end_error;
1997                         }
1998
1999                         initializer_t *designator_initializer
2000                                 = allocate_initializer_zero(INITIALIZER_DESIGNATOR);
2001                         designator_initializer->designator.designator = designator;
2002                         ARR_APP1(initializer_t*, initializers, designator_initializer);
2003
2004                         orig_type = path->top_type;
2005                         type      = orig_type != NULL ? skip_typeref(orig_type) : NULL;
2006                 }
2007
2008                 initializer_t *sub;
2009
2010                 if (token.kind == '{') {
2011                         if (type != NULL && is_type_scalar(type)) {
2012                                 sub = parse_scalar_initializer(type, env->must_be_constant);
2013                         } else {
2014                                 if (type == NULL) {
2015                                         if (env->entity != NULL) {
2016                                                 errorf(HERE, "extra brace group at end of initializer for '%N'", env->entity);
2017                                         } else {
2018                                                 errorf(HERE, "extra brace group at end of initializer");
2019                                         }
2020                                         eat('{');
2021                                 } else {
2022                                         eat('{');
2023                                         descend_into_subtype(path);
2024                                 }
2025
2026                                 add_anchor_token('}');
2027                                 sub = parse_sub_initializer(path, orig_type, top_path_level+1,
2028                                                             env);
2029                                 rem_anchor_token('}');
2030
2031                                 expect('}');
2032
2033                                 if (!type)
2034                                         goto error_parse_next;
2035
2036                                 ascend_from_subtype(path);
2037                         }
2038                 } else {
2039                         /* must be an expression */
2040                         expression_t *expression = parse_assignment_expression();
2041                         mark_vars_read(expression, NULL);
2042
2043                         if (env->must_be_constant && !is_linker_constant(expression)) {
2044                                 errorf(&expression->base.pos,
2045                                        "Initialisation expression '%E' is not constant",
2046                                        expression);
2047                         }
2048
2049                         if (type == NULL) {
2050                                 /* we are already outside, ... */
2051                                 if (outer_type == NULL)
2052                                         goto error_parse_next;
2053                                 type_t *const outer_type_skip = skip_typeref(outer_type);
2054                                 if (is_type_compound(outer_type_skip) &&
2055                                                 !outer_type_skip->compound.compound->complete) {
2056                                         goto error_parse_next;
2057                                 }
2058
2059                                 position_t const* const pos = &expression->base.pos;
2060                                 if (env->entity != NULL) {
2061                                         warningf(WARN_OTHER, pos, "excess elements in initializer for '%N'", env->entity);
2062                                 } else {
2063                                         warningf(WARN_OTHER, pos, "excess elements in initializer");
2064                                 }
2065                                 goto error_parse_next;
2066                         }
2067
2068                         /* handle { "string" } special case */
2069                         if (expression->kind == EXPR_STRING_LITERAL && outer_type != NULL) {
2070                                 result = initializer_from_expression(outer_type, expression);
2071                                 if (result != NULL) {
2072                                         accept(',');
2073                                         if (token.kind != '}') {
2074                                                 warningf(WARN_OTHER, HERE, "excessive elements in initializer for type '%T'", outer_type);
2075                                         }
2076                                         /* TODO: eat , ... */
2077                                         goto out;
2078                                 }
2079                         }
2080
2081                         /* descend into subtypes until expression matches type */
2082                         while (true) {
2083                                 orig_type = path->top_type;
2084                                 type      = skip_typeref(orig_type);
2085
2086                                 sub = initializer_from_expression(orig_type, expression);
2087                                 if (sub != NULL) {
2088                                         break;
2089                                 }
2090                                 if (!is_type_valid(type)) {
2091                                         goto end_error;
2092                                 }
2093                                 if (is_type_scalar(type)) {
2094                                         errorf(&expression->base.pos,
2095                                                         "expression '%E' doesn't match expected type '%T'",
2096                                                         expression, orig_type);
2097                                         goto end_error;
2098                                 }
2099
2100                                 descend_into_subtype(path);
2101                         }
2102                 }
2103
2104                 /* update largest index of top array */
2105                 const type_path_entry_t *first      = &path->path[0];
2106                 type_t                  *first_type = first->type;
2107                 first_type                          = skip_typeref(first_type);
2108                 if (is_type_array(first_type)) {
2109                         size_t index = first->v.index;
2110                         if (index > path->max_index)
2111                                 path->max_index = index;
2112                 }
2113
2114                 /* append to initializers list */
2115                 ARR_APP1(initializer_t*, initializers, sub);
2116
2117 error_parse_next:
2118                 if (!accept(','))
2119                         break;
2120                 if (token.kind == '}') {
2121                         break;
2122                 }
2123
2124                 if (type != NULL) {
2125                         /* advance to the next declaration if we are not at the end */
2126                         advance_current_object(path, top_path_level);
2127                         orig_type = path->top_type;
2128                         if (orig_type != NULL)
2129                                 type = skip_typeref(orig_type);
2130                         else
2131                                 type = NULL;
2132                 }
2133         }
2134
2135         size_t len  = ARR_LEN(initializers);
2136         size_t size = sizeof(initializer_list_t) + len * sizeof(initializers[0]);
2137         result = allocate_ast_zero(size);
2138         result->kind     = INITIALIZER_LIST;
2139         result->list.len = len;
2140         memcpy(&result->list.initializers, initializers,
2141                len * sizeof(initializers[0]));
2142         goto out;
2143
2144 end_error:
2145         skip_initializers();
2146 out:
2147         DEL_ARR_F(initializers);
2148         ascend_to(path, top_path_level+1);
2149         return result;
2150 }
2151
2152 static expression_t *make_size_literal(size_t value)
2153 {
2154         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_INTEGER);
2155         literal->base.type    = type_size_t;
2156
2157         char buf[128];
2158         snprintf(buf, sizeof(buf), "%u", (unsigned) value);
2159         literal->literal.value = make_string(buf);
2160
2161         return literal;
2162 }
2163
2164 /**
2165  * Parses an initializer. Parsers either a compound literal
2166  * (env->declaration == NULL) or an initializer of a declaration.
2167  */
2168 static initializer_t *parse_initializer(parse_initializer_env_t *env)
2169 {
2170         type_t        *type      = skip_typeref(env->type);
2171         size_t         max_index = 0;
2172         initializer_t *result;
2173
2174         if (is_type_scalar(type)) {
2175                 result = parse_scalar_initializer(type, env->must_be_constant);
2176         } else if (token.kind == '{') {
2177                 eat('{');
2178
2179                 type_path_t path;
2180                 memset(&path, 0, sizeof(path));
2181                 path.top_type = env->type;
2182                 path.path     = NEW_ARR_F(type_path_entry_t, 0);
2183
2184                 descend_into_subtype(&path);
2185
2186                 add_anchor_token('}');
2187                 result = parse_sub_initializer(&path, env->type, 1, env);
2188                 rem_anchor_token('}');
2189
2190                 max_index = path.max_index;
2191                 DEL_ARR_F(path.path);
2192
2193                 expect('}');
2194         } else {
2195                 /* parse_scalar_initializer() also works in this case: we simply
2196                  * have an expression without {} around it */
2197                 result = parse_scalar_initializer(type, env->must_be_constant);
2198         }
2199
2200         /* §6.7.8:22 array initializers for arrays with unknown size determine
2201          * the array type size */
2202         if (is_type_array(type) && type->array.size_expression == NULL
2203                         && result != NULL) {
2204                 size_t size;
2205                 switch (result->kind) {
2206                 case INITIALIZER_LIST:
2207                         assert(max_index != 0xdeadbeaf);
2208                         size = max_index + 1;
2209                         break;
2210
2211                 case INITIALIZER_STRING: {
2212                         size = get_string_len(&get_init_string(result)->value) + 1;
2213                         break;
2214                 }
2215
2216                 case INITIALIZER_DESIGNATOR:
2217                 case INITIALIZER_VALUE:
2218                         /* can happen for parse errors */
2219                         size = 0;
2220                         break;
2221
2222                 default:
2223                         internal_errorf(HERE, "invalid initializer type");
2224                 }
2225
2226                 type_t *new_type = duplicate_type(type);
2227
2228                 new_type->array.size_expression   = make_size_literal(size);
2229                 new_type->array.size_constant     = true;
2230                 new_type->array.has_implicit_size = true;
2231                 new_type->array.size              = size;
2232                 env->type = new_type;
2233         }
2234
2235         return result;
2236 }
2237
2238 static void append_entity(scope_t *scope, entity_t *entity)
2239 {
2240         if (scope->last_entity != NULL) {
2241                 scope->last_entity->base.next = entity;
2242         } else {
2243                 scope->entities = entity;
2244         }
2245         entity->base.parent_entity = current_entity;
2246         scope->last_entity         = entity;
2247 }
2248
2249
2250 static compound_t *parse_compound_type_specifier(bool is_struct)
2251 {
2252         position_t const pos = *HERE;
2253         eat(is_struct ? T_struct : T_union);
2254
2255         symbol_t    *symbol     = NULL;
2256         entity_t    *entity     = NULL;
2257         attribute_t *attributes = NULL;
2258
2259         if (token.kind == T___attribute__) {
2260                 attributes = parse_attributes(NULL);
2261         }
2262
2263         entity_kind_tag_t const kind = is_struct ? ENTITY_STRUCT : ENTITY_UNION;
2264         if (token.kind == T_IDENTIFIER) {
2265                 /* the compound has a name, check if we have seen it already */
2266                 symbol = token.base.symbol;
2267                 entity = get_tag(symbol, kind);
2268                 eat(T_IDENTIFIER);
2269
2270                 if (entity != NULL) {
2271                         if (entity->base.parent_scope != current_scope &&
2272                             (token.kind == '{' || token.kind == ';')) {
2273                                 /* we're in an inner scope and have a definition. Shadow
2274                                  * existing definition in outer scope */
2275                                 entity = NULL;
2276                         } else if (entity->compound.complete && token.kind == '{') {
2277                                 position_t const *const ppos = &entity->base.pos;
2278                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2279                                 /* clear members in the hope to avoid further errors */
2280                                 entity->compound.members.entities = NULL;
2281                         }
2282                 }
2283         } else if (token.kind != '{') {
2284                 char const *const msg =
2285                         is_struct ? "while parsing struct type specifier" :
2286                                     "while parsing union type specifier";
2287                 parse_error_expected(msg, T_IDENTIFIER, '{', NULL);
2288
2289                 return NULL;
2290         }
2291
2292         if (entity == NULL) {
2293                 entity = allocate_entity_zero(kind, NAMESPACE_TAG, symbol, &pos);
2294                 entity->compound.alignment = 1;
2295                 entity->base.parent_scope  = current_scope;
2296                 if (symbol != NULL) {
2297                         environment_push(entity);
2298                 }
2299                 append_entity(current_scope, entity);
2300         }
2301
2302         if (token.kind == '{') {
2303                 parse_compound_type_entries(&entity->compound);
2304
2305                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2306                 if (symbol == NULL) {
2307                         assert(anonymous_entity == NULL);
2308                         anonymous_entity = entity;
2309                 }
2310         }
2311
2312         if (attributes != NULL) {
2313                 entity->compound.attributes = attributes;
2314                 handle_entity_attributes(attributes, entity);
2315         }
2316
2317         return &entity->compound;
2318 }
2319
2320 static void parse_enum_entries(type_t *const enum_type)
2321 {
2322         eat('{');
2323
2324         if (token.kind == '}') {
2325                 errorf(HERE, "empty enum not allowed");
2326                 eat('}');
2327                 return;
2328         }
2329
2330         add_anchor_token('}');
2331         add_anchor_token(',');
2332         do {
2333                 add_anchor_token('=');
2334                 position_t pos;
2335                 symbol_t *const symbol = expect_identifier("while parsing enum entry", &pos);
2336                 entity_t *const entity = allocate_entity_zero(ENTITY_ENUM_VALUE, NAMESPACE_NORMAL, symbol, &pos);
2337                 entity->enum_value.enum_type = enum_type;
2338                 rem_anchor_token('=');
2339
2340                 if (accept('=')) {
2341                         expression_t *value = parse_constant_expression();
2342
2343                         value = create_implicit_cast(value, enum_type);
2344                         entity->enum_value.value = value;
2345
2346                         /* TODO semantic */
2347                 }
2348
2349                 record_entity(entity, false);
2350         } while (accept(',') && token.kind != '}');
2351         rem_anchor_token(',');
2352         rem_anchor_token('}');
2353
2354         expect('}');
2355 }
2356
2357 static type_t *parse_enum_specifier(void)
2358 {
2359         position_t const pos = *HERE;
2360         entity_t        *entity;
2361         symbol_t        *symbol;
2362
2363         eat(T_enum);
2364         switch (token.kind) {
2365                 case T_IDENTIFIER:
2366                         symbol = token.base.symbol;
2367                         entity = get_tag(symbol, ENTITY_ENUM);
2368                         eat(T_IDENTIFIER);
2369
2370                         if (entity != NULL) {
2371                                 if (entity->base.parent_scope != current_scope &&
2372                                                 (token.kind == '{' || token.kind == ';')) {
2373                                         /* we're in an inner scope and have a definition. Shadow
2374                                          * existing definition in outer scope */
2375                                         entity = NULL;
2376                                 } else if (entity->enume.complete && token.kind == '{') {
2377                                         position_t const *const ppos = &entity->base.pos;
2378                                         errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2379                                 }
2380                         }
2381                         break;
2382
2383                 case '{':
2384                         entity = NULL;
2385                         symbol = NULL;
2386                         break;
2387
2388                 default:
2389                         parse_error_expected("while parsing enum type specifier",
2390                                         T_IDENTIFIER, '{', NULL);
2391                         return NULL;
2392         }
2393
2394         if (entity == NULL) {
2395                 entity = allocate_entity_zero(ENTITY_ENUM, NAMESPACE_TAG, symbol, &pos);
2396                 entity->base.parent_scope = current_scope;
2397         }
2398
2399         type_t *const type     = allocate_type_zero(TYPE_ENUM);
2400         type->enumt.enume      = &entity->enume;
2401         type->enumt.base.akind = ATOMIC_TYPE_INT;
2402
2403         if (token.kind == '{') {
2404                 if (symbol != NULL) {
2405                         environment_push(entity);
2406                 }
2407                 append_entity(current_scope, entity);
2408                 entity->enume.complete = true;
2409
2410                 parse_enum_entries(type);
2411                 parse_attributes(NULL);
2412
2413                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2414                 if (symbol == NULL) {
2415                         assert(anonymous_entity == NULL);
2416                         anonymous_entity = entity;
2417                 }
2418         } else if (!entity->enume.complete && !(c_mode & _GNUC)) {
2419                 errorf(HERE, "'%T' used before definition (incomplete enums are a GNU extension)", type);
2420         }
2421
2422         return type;
2423 }
2424
2425 /**
2426  * if a symbol is a typedef to another type, return true
2427  */
2428 static bool is_typedef_symbol(symbol_t *symbol)
2429 {
2430         const entity_t *const entity = get_entity(symbol, NAMESPACE_NORMAL);
2431         return entity != NULL && entity->kind == ENTITY_TYPEDEF;
2432 }
2433
2434 static type_t *parse_typeof(void)
2435 {
2436         eat(T___typeof__);
2437
2438         type_t *type;
2439
2440         add_anchor_token(')');
2441         expect('(');
2442
2443         expression_t *expression  = NULL;
2444
2445         switch (token.kind) {
2446         case T_IDENTIFIER:
2447                 if (is_typedef_symbol(token.base.symbol)) {
2448         DECLARATION_START
2449                         type = parse_typename();
2450                 } else {
2451         default:
2452                         expression = parse_expression();
2453                         type       = revert_automatic_type_conversion(expression);
2454                 }
2455                 break;
2456         }
2457
2458         rem_anchor_token(')');
2459         expect(')');
2460
2461         type_t *typeof_type              = allocate_type_zero(TYPE_TYPEOF);
2462         typeof_type->typeoft.expression  = expression;
2463         typeof_type->typeoft.typeof_type = type;
2464
2465         return typeof_type;
2466 }
2467
2468 typedef enum specifiers_t {
2469         SPECIFIER_NONE      = 0,
2470         SPECIFIER_SIGNED    = 1 << 0,
2471         SPECIFIER_UNSIGNED  = 1 << 1,
2472         SPECIFIER_LONG      = 1 << 2,
2473         SPECIFIER_INT       = 1 << 3,
2474         SPECIFIER_DOUBLE    = 1 << 4,
2475         SPECIFIER_CHAR      = 1 << 5,
2476         SPECIFIER_WCHAR_T   = 1 << 6,
2477         SPECIFIER_SHORT     = 1 << 7,
2478         SPECIFIER_LONG_LONG = 1 << 8,
2479         SPECIFIER_FLOAT     = 1 << 9,
2480         SPECIFIER_BOOL      = 1 << 10,
2481         SPECIFIER_VOID      = 1 << 11,
2482         SPECIFIER_INT8      = 1 << 12,
2483         SPECIFIER_INT16     = 1 << 13,
2484         SPECIFIER_INT32     = 1 << 14,
2485         SPECIFIER_INT64     = 1 << 15,
2486         SPECIFIER_INT128    = 1 << 16,
2487         SPECIFIER_COMPLEX   = 1 << 17,
2488         SPECIFIER_IMAGINARY = 1 << 18,
2489 } specifiers_t;
2490
2491 static type_t *get_typedef_type(symbol_t *symbol)
2492 {
2493         entity_t *entity = get_entity(symbol, NAMESPACE_NORMAL);
2494         if (entity == NULL || entity->kind != ENTITY_TYPEDEF)
2495                 return NULL;
2496
2497         type_t *type            = allocate_type_zero(TYPE_TYPEDEF);
2498         type->typedeft.typedefe = &entity->typedefe;
2499
2500         return type;
2501 }
2502
2503 static attribute_t *parse_attribute_ms_property(attribute_t *attribute)
2504 {
2505         attribute_property_argument_t *const property = allocate_ast_zero(sizeof(*property));
2506
2507         add_anchor_token(')');
2508         add_anchor_token(',');
2509         expect('(');
2510
2511         do {
2512                 add_anchor_token('=');
2513                 position_t pos;
2514                 symbol_t *const prop_sym = expect_identifier("while parsing property declspec", &pos);
2515                 rem_anchor_token('=');
2516
2517                 symbol_t **prop = NULL;
2518                 if (prop_sym) {
2519                         if (streq(prop_sym->string, "put")) {
2520                                 prop = &property->put_symbol;
2521                         } else if (streq(prop_sym->string, "get")) {
2522                                 prop = &property->get_symbol;
2523                         } else {
2524                                 errorf(&pos, "expected put or get in property declspec, but got '%Y'", prop_sym);
2525                         }
2526                 }
2527
2528                 add_anchor_token(T_IDENTIFIER);
2529                 expect('=');
2530                 rem_anchor_token(T_IDENTIFIER);
2531
2532                 symbol_t *const sym = expect_identifier("while parsing property declspec", NULL);
2533                 if (prop != NULL)
2534                         *prop = sym ? sym : sym_anonymous;
2535         } while (accept(','));
2536         rem_anchor_token(',');
2537         rem_anchor_token(')');
2538
2539         attribute->a.property = property;
2540
2541         expect(')');
2542         return attribute;
2543 }
2544
2545 static attribute_t *parse_microsoft_extended_decl_modifier_single(void)
2546 {
2547         attribute_kind_t kind = ATTRIBUTE_UNKNOWN;
2548         if (accept(T_restrict)) {
2549                 kind = ATTRIBUTE_MS_RESTRICT;
2550         } else if (token.kind == T_IDENTIFIER) {
2551                 char const *const name = token.base.symbol->string;
2552                 for (attribute_kind_t k = ATTRIBUTE_MS_FIRST; k <= ATTRIBUTE_MS_LAST;
2553                      ++k) {
2554                         const char *attribute_name = get_attribute_name(k);
2555                         if (attribute_name != NULL && streq(attribute_name, name)) {
2556                                 kind = k;
2557                                 break;
2558                         }
2559                 }
2560
2561                 if (kind == ATTRIBUTE_UNKNOWN) {
2562                         warningf(WARN_ATTRIBUTE, HERE, "unknown __declspec '%s' ignored", name);
2563                 }
2564         } else {
2565                 parse_error_expected("while parsing __declspec", T_IDENTIFIER, NULL);
2566                 return NULL;
2567         }
2568
2569         attribute_t *attribute = allocate_attribute_zero(kind);
2570         eat(T_IDENTIFIER);
2571
2572         if (kind == ATTRIBUTE_MS_PROPERTY) {
2573                 return parse_attribute_ms_property(attribute);
2574         }
2575
2576         /* parse arguments */
2577         if (accept('('))
2578                 attribute->a.arguments = parse_attribute_arguments();
2579
2580         return attribute;
2581 }
2582
2583 static attribute_t *parse_microsoft_extended_decl_modifier(attribute_t *first)
2584 {
2585         eat(T__declspec);
2586
2587         add_anchor_token(')');
2588         expect('(');
2589         if (token.kind != ')') {
2590                 attribute_t **anchor = &first;
2591                 do {
2592                         while (*anchor != NULL)
2593                                 anchor = &(*anchor)->next;
2594
2595                         attribute_t *attribute
2596                                 = parse_microsoft_extended_decl_modifier_single();
2597                         if (attribute == NULL)
2598                                 break;
2599
2600                         *anchor = attribute;
2601                         anchor  = &attribute->next;
2602                 } while (accept(','));
2603         }
2604         rem_anchor_token(')');
2605         expect(')');
2606         return first;
2607 }
2608
2609 static entity_t *create_error_entity(symbol_t *symbol, entity_kind_tag_t kind)
2610 {
2611         entity_t *const entity = allocate_entity_zero(kind, NAMESPACE_NORMAL, symbol, HERE);
2612         if (is_declaration(entity)) {
2613                 entity->declaration.type     = type_error_type;
2614                 entity->declaration.implicit = true;
2615         } else if (kind == ENTITY_TYPEDEF) {
2616                 entity->typedefe.type    = type_error_type;
2617                 entity->typedefe.builtin = true;
2618         }
2619         if (kind != ENTITY_COMPOUND_MEMBER)
2620                 record_entity(entity, false);
2621         return entity;
2622 }
2623
2624 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
2625 {
2626         type_t            *type            = NULL;
2627         type_qualifiers_t  qualifiers      = TYPE_QUALIFIER_NONE;
2628         unsigned           type_specifiers = 0;
2629         bool               newtype         = false;
2630         bool               saw_error       = false;
2631
2632         memset(specifiers, 0, sizeof(*specifiers));
2633         specifiers->pos = *HERE;
2634
2635         while (true) {
2636                 specifiers->attributes = parse_attributes(specifiers->attributes);
2637
2638                 switch (token.kind) {
2639                 /* storage class */
2640 #define MATCH_STORAGE_CLASS(token, class)                                  \
2641                 case token:                                                        \
2642                         if (specifiers->storage_class != STORAGE_CLASS_NONE) {         \
2643                                 errorf(HERE, "multiple storage classes in declaration specifiers"); \
2644                         }                                                              \
2645                         specifiers->storage_class = class;                             \
2646                         if (specifiers->thread_local)                                  \
2647                                 goto check_thread_storage_class;                           \
2648                         eat(token); \
2649                         break;
2650
2651                 MATCH_STORAGE_CLASS(T_typedef,  STORAGE_CLASS_TYPEDEF)
2652                 MATCH_STORAGE_CLASS(T_extern,   STORAGE_CLASS_EXTERN)
2653                 MATCH_STORAGE_CLASS(T_static,   STORAGE_CLASS_STATIC)
2654                 MATCH_STORAGE_CLASS(T_auto,     STORAGE_CLASS_AUTO)
2655                 MATCH_STORAGE_CLASS(T_register, STORAGE_CLASS_REGISTER)
2656
2657                 case T__declspec:
2658                         specifiers->attributes
2659                                 = parse_microsoft_extended_decl_modifier(specifiers->attributes);
2660                         break;
2661
2662                 case T__Thread_local:
2663                         if (specifiers->thread_local) {
2664                                 errorf(HERE, "duplicate %K", &token);
2665                         } else {
2666                                 specifiers->thread_local = true;
2667 check_thread_storage_class:
2668                                 switch (specifiers->storage_class) {
2669                                         case STORAGE_CLASS_EXTERN:
2670                                         case STORAGE_CLASS_NONE:
2671                                         case STORAGE_CLASS_STATIC:
2672                                                 break;
2673
2674                                                 char const* wrong;
2675                                         case STORAGE_CLASS_AUTO:     wrong = "auto";     goto wrong_thread_storage_class;
2676                                         case STORAGE_CLASS_REGISTER: wrong = "register"; goto wrong_thread_storage_class;
2677                                         case STORAGE_CLASS_TYPEDEF:  wrong = "typedef";  goto wrong_thread_storage_class;
2678 wrong_thread_storage_class:
2679                                                 errorf(HERE, "%K used with '%s'", &token, wrong);
2680                                                 break;
2681                                 }
2682                         }
2683                         next_token();
2684                         break;
2685
2686                 /* type qualifiers */
2687 #define MATCH_TYPE_QUALIFIER(token, qualifier)                          \
2688                 case token:                                                     \
2689                         qualifiers |= qualifier;                                    \
2690                         eat(token); \
2691                         break
2692
2693                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
2694                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
2695                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
2696                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
2697                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
2698                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
2699                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
2700                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
2701
2702                 /* type specifiers */
2703 #define MATCH_SPECIFIER(token, specifier, name)                         \
2704                 case token:                                                     \
2705                         if (type_specifiers & specifier) {                           \
2706                                 errorf(HERE, "multiple " name " type specifiers given"); \
2707                         } else {                                                    \
2708                                 type_specifiers |= specifier;                           \
2709                         }                                                           \
2710                         eat(token); \
2711                         break
2712
2713                 MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool");
2714                 MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex");
2715                 MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary");
2716                 MATCH_SPECIFIER(T__int128,    SPECIFIER_INT128,    "_int128");
2717                 MATCH_SPECIFIER(T__int16,     SPECIFIER_INT16,     "_int16");
2718                 MATCH_SPECIFIER(T__int32,     SPECIFIER_INT32,     "_int32");
2719                 MATCH_SPECIFIER(T__int64,     SPECIFIER_INT64,     "_int64");
2720                 MATCH_SPECIFIER(T__int8,      SPECIFIER_INT8,      "_int8");
2721                 MATCH_SPECIFIER(T_bool,       SPECIFIER_BOOL,      "bool");
2722                 MATCH_SPECIFIER(T_char,       SPECIFIER_CHAR,      "char");
2723                 MATCH_SPECIFIER(T_double,     SPECIFIER_DOUBLE,    "double");
2724                 MATCH_SPECIFIER(T_float,      SPECIFIER_FLOAT,     "float");
2725                 MATCH_SPECIFIER(T_int,        SPECIFIER_INT,       "int");
2726                 MATCH_SPECIFIER(T_short,      SPECIFIER_SHORT,     "short");
2727                 MATCH_SPECIFIER(T_signed,     SPECIFIER_SIGNED,    "signed");
2728                 MATCH_SPECIFIER(T_unsigned,   SPECIFIER_UNSIGNED,  "unsigned");
2729                 MATCH_SPECIFIER(T_void,       SPECIFIER_VOID,      "void");
2730                 MATCH_SPECIFIER(T_wchar_t,    SPECIFIER_WCHAR_T,   "wchar_t");
2731
2732                 case T_inline:
2733                         eat(T_inline);
2734                         specifiers->is_inline = true;
2735                         break;
2736
2737 #if 0
2738                 case T__forceinline:
2739                         eat(T__forceinline);
2740                         specifiers->modifiers |= DM_FORCEINLINE;
2741                         break;
2742 #endif
2743
2744                 case T_long:
2745                         if (type_specifiers & SPECIFIER_LONG_LONG) {
2746                                 errorf(HERE, "too many long type specifiers given");
2747                         } else if (type_specifiers & SPECIFIER_LONG) {
2748                                 type_specifiers |= SPECIFIER_LONG_LONG;
2749                         } else {
2750                                 type_specifiers |= SPECIFIER_LONG;
2751                         }
2752                         eat(T_long);
2753                         break;
2754
2755 #define CHECK_DOUBLE_TYPE() \
2756         (type != NULL ? errorf(HERE, "multiple types in declaration specifiers") : (void)0)
2757
2758                 case T_struct:
2759                         CHECK_DOUBLE_TYPE();
2760                         type = allocate_type_zero(TYPE_COMPOUND_STRUCT);
2761
2762                         type->compound.compound = parse_compound_type_specifier(true);
2763                         break;
2764                 case T_union:
2765                         CHECK_DOUBLE_TYPE();
2766                         type = allocate_type_zero(TYPE_COMPOUND_UNION);
2767                         type->compound.compound = parse_compound_type_specifier(false);
2768                         break;
2769                 case T_enum:
2770                         CHECK_DOUBLE_TYPE();
2771                         type = parse_enum_specifier();
2772                         break;
2773                 case T___typeof__:
2774                         CHECK_DOUBLE_TYPE();
2775                         type = parse_typeof();
2776                         break;
2777                 case T___builtin_va_list:
2778                         CHECK_DOUBLE_TYPE();
2779                         type = duplicate_type(type_valist);
2780                         eat(T___builtin_va_list);
2781                         break;
2782
2783                 case T_IDENTIFIER: {
2784                         /* only parse identifier if we haven't found a type yet */
2785                         if (type != NULL || type_specifiers != 0) {
2786                                 /* Be somewhat resilient to typos like 'unsigned lng* f()' in a
2787                                  * declaration, so it doesn't generate errors about expecting '(' or
2788                                  * '{' later on. */
2789                                 switch (look_ahead(1)->kind) {
2790                                         STORAGE_CLASSES
2791                                         TYPE_SPECIFIERS
2792                                         case T_const:
2793                                         case T_restrict:
2794                                         case T_volatile:
2795                                         case T_inline:
2796                                         case T__forceinline: /* ^ DECLARATION_START except for __attribute__ */
2797                                         case T_IDENTIFIER:
2798                                         case '&':
2799                                         case '*':
2800                                                 errorf(HERE, "discarding stray %K in declaration specifier", &token);
2801                                                 eat(T_IDENTIFIER);
2802                                                 continue;
2803
2804                                         default:
2805                                                 goto finish_specifiers;
2806                                 }
2807                         }
2808
2809                         type_t *const typedef_type = get_typedef_type(token.base.symbol);
2810                         if (typedef_type == NULL) {
2811                                 /* Be somewhat resilient to typos like 'vodi f()' at the beginning of a
2812                                  * declaration, so it doesn't generate 'implicit int' followed by more
2813                                  * errors later on. */
2814                                 token_kind_t const la1_type = (token_kind_t)look_ahead(1)->kind;
2815                                 switch (la1_type) {
2816                                         DECLARATION_START
2817                                         case T_IDENTIFIER:
2818                                         case '&':
2819                                         case '*': {
2820                                                 errorf(HERE, "%K does not name a type", &token);
2821
2822                                                 entity_t *const entity = create_error_entity(token.base.symbol, ENTITY_TYPEDEF);
2823
2824                                                 type = allocate_type_zero(TYPE_TYPEDEF);
2825                                                 type->typedeft.typedefe = &entity->typedefe;
2826
2827                                                 eat(T_IDENTIFIER);
2828                                                 saw_error = true;
2829                                                 continue;
2830                                         }
2831
2832                                         default:
2833                                                 goto finish_specifiers;
2834                                 }
2835                         }
2836
2837                         eat(T_IDENTIFIER);
2838                         type = typedef_type;
2839                         break;
2840                 }
2841
2842                 /* function specifier */
2843                 default:
2844                         goto finish_specifiers;
2845                 }
2846         }
2847
2848 finish_specifiers:
2849         specifiers->attributes = parse_attributes(specifiers->attributes);
2850
2851         if (type == NULL || (saw_error && type_specifiers != 0)) {
2852                 position_t const* const pos = &specifiers->pos;
2853                 atomic_type_kind_t atomic_type;
2854
2855                 /* match valid basic types */
2856                 switch (type_specifiers & ~(SPECIFIER_COMPLEX|SPECIFIER_IMAGINARY)) {
2857                 case SPECIFIER_VOID:
2858                         if (type_specifiers & (SPECIFIER_COMPLEX|SPECIFIER_IMAGINARY)) {
2859                                 if (type_specifiers & SPECIFIER_COMPLEX)
2860                                         errorf(pos, "_Complex specifier is invalid for void");
2861                                 if (type_specifiers & SPECIFIER_IMAGINARY)
2862                                         errorf(pos, "_Imaginary specifier is invalid for void");
2863                                 type_specifiers &= ~(SPECIFIER_COMPLEX|SPECIFIER_IMAGINARY);
2864                         }
2865                         atomic_type = ATOMIC_TYPE_VOID;
2866                         break;
2867                 case SPECIFIER_WCHAR_T:
2868                         atomic_type = ATOMIC_TYPE_WCHAR_T;
2869                         break;
2870                 case SPECIFIER_CHAR:
2871                         atomic_type = ATOMIC_TYPE_CHAR;
2872                         break;
2873                 case SPECIFIER_SIGNED | SPECIFIER_CHAR:
2874                         atomic_type = ATOMIC_TYPE_SCHAR;
2875                         break;
2876                 case SPECIFIER_UNSIGNED | SPECIFIER_CHAR:
2877                         atomic_type = ATOMIC_TYPE_UCHAR;
2878                         break;
2879                 case SPECIFIER_SHORT:
2880                 case SPECIFIER_SIGNED | SPECIFIER_SHORT:
2881                 case SPECIFIER_SHORT | SPECIFIER_INT:
2882                 case SPECIFIER_SIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2883                         atomic_type = ATOMIC_TYPE_SHORT;
2884                         break;
2885                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT:
2886                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2887                         atomic_type = ATOMIC_TYPE_USHORT;
2888                         break;
2889                 case SPECIFIER_INT:
2890                 case SPECIFIER_SIGNED:
2891                 case SPECIFIER_SIGNED | SPECIFIER_INT:
2892                         atomic_type = ATOMIC_TYPE_INT;
2893                         break;
2894                 case SPECIFIER_UNSIGNED:
2895                 case SPECIFIER_UNSIGNED | SPECIFIER_INT:
2896                         atomic_type = ATOMIC_TYPE_UINT;
2897                         break;
2898                 case SPECIFIER_LONG:
2899                 case SPECIFIER_SIGNED | SPECIFIER_LONG:
2900                 case SPECIFIER_LONG | SPECIFIER_INT:
2901                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2902                         atomic_type = ATOMIC_TYPE_LONG;
2903                         break;
2904                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:
2905                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2906                         atomic_type = ATOMIC_TYPE_ULONG;
2907                         break;
2908
2909                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2910                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2911                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG | SPECIFIER_INT:
2912                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2913                         | SPECIFIER_INT:
2914                         atomic_type = ATOMIC_TYPE_LONGLONG;
2915                         goto warn_about_long_long;
2916
2917                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2918                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2919                         | SPECIFIER_INT:
2920                         atomic_type = ATOMIC_TYPE_ULONGLONG;
2921 warn_about_long_long:
2922                         warningf(WARN_LONG_LONG, &specifiers->pos, "ISO C90 does not support 'long long'");
2923                         break;
2924
2925                 case SPECIFIER_UNSIGNED | SPECIFIER_INT8:
2926                         atomic_type = unsigned_int8_type_kind;
2927                         break;
2928
2929                 case SPECIFIER_UNSIGNED | SPECIFIER_INT16:
2930                         atomic_type = unsigned_int16_type_kind;
2931                         break;
2932
2933                 case SPECIFIER_UNSIGNED | SPECIFIER_INT32:
2934                         atomic_type = unsigned_int32_type_kind;
2935                         break;
2936
2937                 case SPECIFIER_UNSIGNED | SPECIFIER_INT64:
2938                         atomic_type = unsigned_int64_type_kind;
2939                         break;
2940
2941                 case SPECIFIER_UNSIGNED | SPECIFIER_INT128:
2942                         atomic_type = unsigned_int128_type_kind;
2943                         break;
2944
2945                 case SPECIFIER_INT8:
2946                 case SPECIFIER_SIGNED | SPECIFIER_INT8:
2947                         atomic_type = int8_type_kind;
2948                         break;
2949
2950                 case SPECIFIER_INT16:
2951                 case SPECIFIER_SIGNED | SPECIFIER_INT16:
2952                         atomic_type = int16_type_kind;
2953                         break;
2954
2955                 case SPECIFIER_INT32:
2956                 case SPECIFIER_SIGNED | SPECIFIER_INT32:
2957                         atomic_type = int32_type_kind;
2958                         break;
2959
2960                 case SPECIFIER_INT64:
2961                 case SPECIFIER_SIGNED | SPECIFIER_INT64:
2962                         atomic_type = int64_type_kind;
2963                         break;
2964
2965                 case SPECIFIER_INT128:
2966                 case SPECIFIER_SIGNED | SPECIFIER_INT128:
2967                         atomic_type = int128_type_kind;
2968                         break;
2969
2970                 case SPECIFIER_FLOAT:
2971                         atomic_type = ATOMIC_TYPE_FLOAT;
2972                         break;
2973                 case SPECIFIER_DOUBLE:
2974                         atomic_type = ATOMIC_TYPE_DOUBLE;
2975                         break;
2976                 case SPECIFIER_LONG | SPECIFIER_DOUBLE:
2977                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
2978                         break;
2979                 case SPECIFIER_BOOL:
2980                         if (type_specifiers & (SPECIFIER_COMPLEX|SPECIFIER_IMAGINARY)) {
2981                                 if (type_specifiers & SPECIFIER_COMPLEX)
2982                                         errorf(pos, "_Complex specifier is invalid for _Bool");
2983                                 if (type_specifiers & SPECIFIER_IMAGINARY)
2984                                         errorf(pos, "_Imaginary specifier is invalid for _Bool");
2985                                 type_specifiers &= ~(SPECIFIER_COMPLEX|SPECIFIER_IMAGINARY);
2986                         }
2987                         atomic_type = ATOMIC_TYPE_BOOL;
2988                         break;
2989                 default: {
2990                         /* invalid specifier combination, give an error message */
2991                         if (type_specifiers == 0) {
2992                                 if (!saw_error) {
2993                                         /* ISO/IEC 14882:1998(E) §C.1.5:4 */
2994                                         if (!(c_mode & _CXX) && !strict_mode) {
2995                                                 warningf(WARN_IMPLICIT_INT, pos, "no type specifiers in declaration, using 'int'");
2996                                                 atomic_type = ATOMIC_TYPE_INT;
2997                                                 break;
2998                                         } else {
2999                                                 errorf(pos, "no type specifiers given in declaration");
3000                                         }
3001                                 }
3002                         } else if (type_specifiers == SPECIFIER_COMPLEX) {
3003                                 warningf(WARN_OTHER, pos, "_Complex requires a type specifier; assuming '_Complex double'");
3004                                 atomic_type = ATOMIC_TYPE_DOUBLE;
3005                                 break;
3006                         } else if ((type_specifiers & SPECIFIER_SIGNED) &&
3007                                   (type_specifiers & SPECIFIER_UNSIGNED)) {
3008                                 errorf(pos, "signed and unsigned specifiers given");
3009                         } else if (type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
3010                                 errorf(pos, "only integer types can be signed or unsigned");
3011                         } else {
3012                                 errorf(pos, "multiple datatypes in declaration");
3013                         }
3014                         specifiers->type = type_error_type;
3015                         return;
3016                 }
3017                 }
3018
3019                 if (type_specifiers & SPECIFIER_COMPLEX) {
3020                         type = allocate_type_zero(TYPE_COMPLEX);
3021                 } else if (type_specifiers & SPECIFIER_IMAGINARY) {
3022                         type = allocate_type_zero(TYPE_IMAGINARY);
3023                 } else {
3024                         type = allocate_type_zero(TYPE_ATOMIC);
3025                 }
3026                 type->atomic.akind = atomic_type;
3027                 newtype = true;
3028         } else if (type_specifiers != 0) {
3029                 errorf(&specifiers->pos, "multiple datatypes in declaration");
3030         }
3031
3032         /* FIXME: check type qualifiers here */
3033         type->base.qualifiers = qualifiers;
3034
3035         if (newtype) {
3036                 type = identify_new_type(type);
3037         } else {
3038                 type = typehash_insert(type);
3039         }
3040
3041         if (specifiers->attributes != NULL)
3042                 type = handle_type_attributes(specifiers->attributes, type);
3043         specifiers->type = type;
3044 }
3045
3046 static type_qualifiers_t parse_type_qualifiers(void)
3047 {
3048         type_qualifiers_t qualifiers = TYPE_QUALIFIER_NONE;
3049
3050         while (true) {
3051                 switch (token.kind) {
3052                 /* type qualifiers */
3053                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
3054                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
3055                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
3056                 /* microsoft extended type modifiers */
3057                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
3058                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
3059                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
3060                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
3061                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
3062
3063                 default:
3064                         return qualifiers;
3065                 }
3066         }
3067 }
3068
3069 /**
3070  * Parses an K&R identifier list
3071  */
3072 static void parse_identifier_list(scope_t *scope)
3073 {
3074         assert(token.kind == T_IDENTIFIER);
3075         do {
3076                 entity_t *const entity = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, token.base.symbol, HERE);
3077                 /* a K&R parameter has no type, yet */
3078                 eat(T_IDENTIFIER);
3079
3080                 if (scope != NULL)
3081                         append_entity(scope, entity);
3082         } while (accept(',') && token.kind == T_IDENTIFIER);
3083 }
3084
3085 static entity_t *parse_parameter(void)
3086 {
3087         declaration_specifiers_t specifiers;
3088         parse_declaration_specifiers(&specifiers);
3089
3090         entity_t *entity = parse_declarator(&specifiers,
3091                         DECL_MAY_BE_ABSTRACT | DECL_IS_PARAMETER);
3092         anonymous_entity = NULL;
3093         return entity;
3094 }
3095
3096 static void semantic_parameter_incomplete(const entity_t *entity)
3097 {
3098         assert(entity->kind == ENTITY_PARAMETER);
3099
3100         /* §6.7.5.3:4  After adjustment, the parameters in a parameter type
3101          *             list in a function declarator that is part of a
3102          *             definition of that function shall not have
3103          *             incomplete type. */
3104         type_t *type = skip_typeref(entity->declaration.type);
3105         if (is_type_incomplete(type)) {
3106                 errorf(&entity->base.pos, "'%N' has incomplete type", entity);
3107         }
3108 }
3109
3110 static bool has_parameters(void)
3111 {
3112         /* func(void) is not a parameter */
3113         if (look_ahead(1)->kind != ')')
3114                 return true;
3115         if (token.kind == T_IDENTIFIER) {
3116                 entity_t const *const entity = get_entity(token.base.symbol, NAMESPACE_NORMAL);
3117                 if (entity == NULL)
3118                         return true;
3119                 if (entity->kind != ENTITY_TYPEDEF)
3120                         return true;
3121                 type_t const *const type = skip_typeref(entity->typedefe.type);
3122                 if (!is_type_void(type))
3123                         return true;
3124                 if (c_mode & _CXX) {
3125                         /* ISO/IEC 14882:1998(E) §8.3.5:2  It must be literally (void).  A typedef
3126                          * is not allowed. */
3127                         errorf(HERE, "empty parameter list defined with a typedef of 'void' not allowed in C++");
3128                 } else if (type->base.qualifiers != TYPE_QUALIFIER_NONE) {
3129                         /* §6.7.5.3:10  Qualification is not allowed here. */
3130                         errorf(HERE, "'void' as parameter must not have type qualifiers");
3131                 }
3132         } else if (token.kind != T_void) {
3133                 return true;
3134         }
3135         next_token();
3136         return false;
3137 }
3138
3139 /**
3140  * Parses function type parameters (and optionally creates variable_t entities
3141  * for them in a scope)
3142  */
3143 static void parse_parameters(function_type_t *type, scope_t *scope)
3144 {
3145         add_anchor_token(')');
3146         eat('(');
3147
3148         if (token.kind == T_IDENTIFIER            &&
3149             !is_typedef_symbol(token.base.symbol) &&
3150             (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
3151                 type->kr_style_parameters = true;
3152                 parse_identifier_list(scope);
3153         } else if (token.kind == ')') {
3154                 /* ISO/IEC 14882:1998(E) §C.1.6:1 */
3155                 if (!(c_mode & _CXX))
3156                         type->unspecified_parameters = true;
3157         } else if (has_parameters()) {
3158                 function_parameter_t **anchor = &type->parameters;
3159                 add_anchor_token(',');
3160                 do {
3161                         switch (token.kind) {
3162                         case T_DOTDOTDOT:
3163                                 eat(T_DOTDOTDOT);
3164                                 type->variadic = true;
3165                                 goto parameters_finished;
3166
3167                         case T_IDENTIFIER:
3168                         DECLARATION_START
3169                         {
3170                                 entity_t *entity = parse_parameter();
3171                                 if (entity->kind == ENTITY_TYPEDEF) {
3172                                         errorf(&entity->base.pos,
3173                                                         "typedef not allowed as function parameter");
3174                                         break;
3175                                 }
3176                                 assert(is_declaration(entity));
3177
3178                                 semantic_parameter_incomplete(entity);
3179
3180                                 function_parameter_t *const parameter =
3181                                         allocate_parameter(entity->declaration.type);
3182
3183                                 if (scope != NULL) {
3184                                         append_entity(scope, entity);
3185                                 }
3186
3187                                 *anchor = parameter;
3188                                 anchor  = &parameter->next;
3189                                 break;
3190                         }
3191
3192                         default:
3193                                 goto parameters_finished;
3194                         }
3195                 } while (accept(','));
3196 parameters_finished:
3197                 rem_anchor_token(',');
3198         }
3199
3200         rem_anchor_token(')');
3201         expect(')');
3202 }
3203
3204 typedef enum construct_type_kind_t {
3205         CONSTRUCT_POINTER = 1,
3206         CONSTRUCT_REFERENCE,
3207         CONSTRUCT_FUNCTION,
3208         CONSTRUCT_ARRAY
3209 } construct_type_kind_t;
3210
3211 typedef union construct_type_t construct_type_t;
3212
3213 typedef struct construct_type_base_t {
3214         construct_type_kind_t kind;
3215         position_t            pos;
3216         construct_type_t     *next;
3217 } construct_type_base_t;
3218
3219 typedef struct parsed_pointer_t {
3220         construct_type_base_t  base;
3221         type_qualifiers_t      type_qualifiers;
3222         variable_t            *base_variable;  /**< MS __based extension. */
3223 } parsed_pointer_t;
3224
3225 typedef struct parsed_reference_t {
3226         construct_type_base_t base;
3227 } parsed_reference_t;
3228
3229 typedef struct construct_function_type_t {
3230         construct_type_base_t  base;
3231         type_t                *function_type;
3232 } construct_function_type_t;
3233
3234 typedef struct parsed_array_t {
3235         construct_type_base_t  base;
3236         type_qualifiers_t      type_qualifiers;
3237         bool                   is_static;
3238         bool                   is_variable;
3239         expression_t          *size;
3240 } parsed_array_t;
3241
3242 union construct_type_t {
3243         construct_type_kind_t     kind;
3244         construct_type_base_t     base;
3245         parsed_pointer_t          pointer;
3246         parsed_reference_t        reference;
3247         construct_function_type_t function;
3248         parsed_array_t            array;
3249 };
3250
3251 static construct_type_t *allocate_declarator_zero(construct_type_kind_t const kind, size_t const size)
3252 {
3253         construct_type_t *const cons = obstack_alloc(&temp_obst, size);
3254         memset(cons, 0, size);
3255         cons->kind     = kind;
3256         cons->base.pos = *HERE;
3257         return cons;
3258 }
3259
3260 /* §6.7.5.1 */
3261 static construct_type_t *parse_pointer_declarator(void)
3262 {
3263         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_POINTER, sizeof(parsed_pointer_t));
3264         eat('*');
3265         cons->pointer.type_qualifiers = parse_type_qualifiers();
3266         //cons->pointer.base_variable   = base_variable;
3267
3268         return cons;
3269 }
3270
3271 /* ISO/IEC 14882:1998(E) §8.3.2 */
3272 static construct_type_t *parse_reference_declarator(void)
3273 {
3274         if (!(c_mode & _CXX))
3275                 errorf(HERE, "references are only available for C++");
3276
3277         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_REFERENCE, sizeof(parsed_reference_t));
3278         eat('&');
3279
3280         return cons;
3281 }
3282
3283 /* §6.7.5.2 */
3284 static construct_type_t *parse_array_declarator(void)
3285 {
3286         construct_type_t *const cons  = allocate_declarator_zero(CONSTRUCT_ARRAY, sizeof(parsed_array_t));
3287         parsed_array_t   *const array = &cons->array;
3288
3289         eat('[');
3290         add_anchor_token(']');
3291
3292         bool is_static = accept(T_static);
3293
3294         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
3295
3296         if (!is_static)
3297                 is_static = accept(T_static);
3298
3299         array->type_qualifiers = type_qualifiers;
3300         array->is_static       = is_static;
3301
3302         expression_t *size = NULL;
3303         if (token.kind == '*' && look_ahead(1)->kind == ']') {
3304                 array->is_variable = true;
3305                 eat('*');
3306         } else if (token.kind != ']') {
3307                 size = parse_assignment_expression();
3308
3309                 /* §6.7.5.2:1  Array size must have integer type */
3310                 type_t *const orig_type = size->base.type;
3311                 type_t *const type      = skip_typeref(orig_type);
3312                 if (!is_type_integer(type) && is_type_valid(type)) {
3313                         errorf(&size->base.pos,
3314                                "array size '%E' must have integer type but has type '%T'",
3315                                size, orig_type);
3316                 }
3317
3318                 array->size = size;
3319                 mark_vars_read(size, NULL);
3320         }
3321
3322         if (is_static && size == NULL)
3323                 errorf(&array->base.pos, "static array parameters require a size");
3324
3325         rem_anchor_token(']');
3326         expect(']');
3327         return cons;
3328 }
3329
3330 /* §6.7.5.3 */
3331 static construct_type_t *parse_function_declarator(scope_t *scope)
3332 {
3333         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_FUNCTION, sizeof(construct_function_type_t));
3334
3335         type_t          *type  = allocate_type_zero(TYPE_FUNCTION);
3336         function_type_t *ftype = &type->function;
3337
3338         ftype->linkage            = current_linkage;
3339         ftype->calling_convention = CC_DEFAULT;
3340
3341         parse_parameters(ftype, scope);
3342
3343         cons->function.function_type = type;
3344
3345         return cons;
3346 }
3347
3348 typedef struct parse_declarator_env_t {
3349         bool              may_be_abstract : 1;
3350         bool              must_be_abstract : 1;
3351         decl_modifiers_t  modifiers;
3352         symbol_t         *symbol;
3353         position_t        pos;
3354         scope_t           parameters;
3355         attribute_t      *attributes;
3356 } parse_declarator_env_t;
3357
3358 /* §6.7.5 */
3359 static construct_type_t *parse_inner_declarator(parse_declarator_env_t *env)
3360 {
3361         /* construct a single linked list of construct_type_t's which describe
3362          * how to construct the final declarator type */
3363         construct_type_t  *first      = NULL;
3364         construct_type_t **anchor     = &first;
3365
3366         env->attributes = parse_attributes(env->attributes);
3367
3368         for (;;) {
3369                 construct_type_t *type;
3370                 //variable_t       *based = NULL; /* MS __based extension */
3371                 switch (token.kind) {
3372                         case '&':
3373                                 type = parse_reference_declarator();
3374                                 break;
3375
3376                         case T__based: {
3377                                 panic("based not supported anymore");
3378                                 /* FALLTHROUGH */
3379                         }
3380
3381                         case '*':
3382                                 type = parse_pointer_declarator();
3383                                 break;
3384
3385                         default:
3386                                 goto ptr_operator_end;
3387                 }
3388
3389                 *anchor = type;
3390                 anchor  = &type->base.next;
3391
3392                 /* TODO: find out if this is correct */
3393                 env->attributes = parse_attributes(env->attributes);
3394         }
3395
3396 ptr_operator_end: ;
3397         construct_type_t *inner_types = NULL;
3398
3399         switch (token.kind) {
3400         case T_IDENTIFIER:
3401                 if (env->must_be_abstract) {
3402                         errorf(HERE, "no identifier expected in typename");
3403                 } else {
3404                         env->symbol = token.base.symbol;
3405                         env->pos    = *HERE;
3406                 }
3407                 eat(T_IDENTIFIER);
3408                 break;
3409
3410         case '(': {
3411                 /* Parenthesized declarator or function declarator? */
3412                 token_t const *const la1 = look_ahead(1);
3413                 switch (la1->kind) {
3414                         case T_IDENTIFIER:
3415                                 if (is_typedef_symbol(la1->base.symbol)) {
3416                         case ')':
3417                                         /* §6.7.6:2 footnote 126:  Empty parentheses in a type name are
3418                                          * interpreted as ``function with no parameter specification'', rather
3419                                          * than redundant parentheses around the omitted identifier. */
3420                         default:
3421                                         /* Function declarator. */
3422                                         if (!env->may_be_abstract) {
3423                                                 errorf(HERE, "function declarator must have a name");
3424                                         }
3425                                 } else {
3426                         case '&':
3427                         case '(':
3428                         case '*':
3429                         case '[':
3430                         case T___attribute__: /* FIXME __attribute__ might also introduce a parameter of a function declarator. */
3431                                         /* Paranthesized declarator. */
3432                                         eat('(');
3433                                         add_anchor_token(')');
3434                                         inner_types = parse_inner_declarator(env);
3435                                         if (inner_types != NULL) {
3436                                                 /* All later declarators only modify the return type */
3437                                                 env->must_be_abstract = true;
3438                                         }
3439                                         rem_anchor_token(')');
3440                                         expect(')');
3441                                 }
3442                                 break;
3443                 }
3444                 break;
3445         }
3446
3447         default:
3448                 if (env->may_be_abstract)
3449                         break;
3450                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', NULL);
3451                 eat_until_anchor();
3452                 return NULL;
3453         }
3454
3455         construct_type_t **const p = anchor;
3456
3457         for (;;) {
3458                 construct_type_t *type;
3459                 switch (token.kind) {
3460                 case '(': {
3461                         scope_t *scope = NULL;
3462                         if (!env->must_be_abstract) {
3463                                 scope = &env->parameters;
3464                         }
3465
3466                         type = parse_function_declarator(scope);
3467                         break;
3468                 }
3469                 case '[':
3470                         type = parse_array_declarator();
3471                         break;
3472                 default:
3473                         goto declarator_finished;
3474                 }
3475
3476                 /* insert in the middle of the list (at p) */
3477                 type->base.next = *p;
3478                 *p              = type;
3479                 if (anchor == p)
3480                         anchor = &type->base.next;
3481         }
3482
3483 declarator_finished:
3484         /* append inner_types at the end of the list, we don't to set anchor anymore
3485          * as it's not needed anymore */
3486         *anchor = inner_types;
3487
3488         return first;
3489 }
3490
3491 static type_t *construct_declarator_type(construct_type_t *construct_list,
3492                                          type_t *type)
3493 {
3494         construct_type_t *iter = construct_list;
3495         for (; iter != NULL; iter = iter->base.next) {
3496                 position_t const* const pos = &iter->base.pos;
3497                 switch (iter->kind) {
3498                 case CONSTRUCT_FUNCTION: {
3499                         construct_function_type_t *function      = &iter->function;
3500                         type_t                    *function_type = function->function_type;
3501
3502                         function_type->function.return_type = type;
3503
3504                         type_t *skipped_return_type = skip_typeref(type);
3505                         /* §6.7.5.3:1 */
3506                         if (is_type_function(skipped_return_type)) {
3507                                 errorf(pos, "function returning function is not allowed");
3508                         } else if (is_type_array(skipped_return_type)) {
3509                                 errorf(pos, "function returning array is not allowed");
3510                         } else {
3511                                 if (skipped_return_type->base.qualifiers != 0) {
3512                                         warningf(WARN_IGNORED_QUALIFIERS, pos, "type qualifiers in return type of function type are meaningless");
3513                                 }
3514                         }
3515
3516                         /* The function type was constructed earlier.  Freeing it here will
3517                          * destroy other types. */
3518                         type = typehash_insert(function_type);
3519                         continue;
3520                 }
3521
3522                 case CONSTRUCT_POINTER: {
3523                         if (is_type_reference(skip_typeref(type)))
3524                                 errorf(pos, "cannot declare a pointer to reference");
3525
3526                         parsed_pointer_t *pointer = &iter->pointer;
3527                         type = make_based_pointer_type(type, pointer->type_qualifiers, pointer->base_variable);
3528                         continue;
3529                 }
3530
3531                 case CONSTRUCT_REFERENCE:
3532                         if (is_type_reference(skip_typeref(type)))
3533                                 errorf(pos, "cannot declare a reference to reference");
3534
3535                         type = make_reference_type(type);
3536                         continue;
3537
3538                 case CONSTRUCT_ARRAY: {
3539                         if (is_type_reference(skip_typeref(type)))
3540                                 errorf(pos, "cannot declare an array of references");
3541
3542                         parsed_array_t *array      = &iter->array;
3543                         type_t         *array_type = allocate_type_zero(TYPE_ARRAY);
3544
3545                         expression_t *size_expression = array->size;
3546                         if (size_expression != NULL) {
3547                                 size_expression
3548                                         = create_implicit_cast(size_expression, type_size_t);
3549                         }
3550
3551                         array_type->base.qualifiers       = array->type_qualifiers;
3552                         array_type->array.element_type    = type;
3553                         array_type->array.is_static       = array->is_static;
3554                         array_type->array.is_variable     = array->is_variable;
3555                         array_type->array.size_expression = size_expression;
3556
3557                         if (size_expression != NULL) {
3558                                 switch (is_constant_expression(size_expression)) {
3559                                 case EXPR_CLASS_INTEGER_CONSTANT: {
3560                                         long const size = fold_constant_to_int(size_expression);
3561                                         array_type->array.size          = size;
3562                                         array_type->array.size_constant = true;
3563                                         /* §6.7.5.2:1  If the expression is a constant expression,
3564                                          * it shall have a value greater than zero. */
3565                                         if (size < 0) {
3566                                                 errorf(&size_expression->base.pos,
3567                                                            "size of array must be greater than zero");
3568                                         } else if (size == 0 && !GNU_MODE) {
3569                                                 errorf(&size_expression->base.pos,
3570                                                            "size of array must be greater than zero (zero length arrays are a GCC extension)");
3571                                         }
3572                                         break;
3573                                 }
3574
3575                                 case EXPR_CLASS_CONSTANT:
3576                                 case EXPR_CLASS_VARIABLE:
3577                                         array_type->array.is_vla = true;
3578                                         break;
3579
3580                                 case EXPR_CLASS_ERROR:
3581                                         break;
3582                                 }
3583                         }
3584
3585                         type_t *skipped_type = skip_typeref(type);
3586                         /* §6.7.5.2:1 */
3587                         if (is_type_incomplete(skipped_type)) {
3588                                 errorf(pos, "array of incomplete type '%T' is not allowed", type);
3589                         } else if (is_type_function(skipped_type)) {
3590                                 errorf(pos, "array of functions is not allowed");
3591                         }
3592                         type = identify_new_type(array_type);
3593                         continue;
3594                 }
3595                 }
3596                 internal_errorf(pos, "invalid type construction found");
3597         }
3598
3599         return type;
3600 }
3601
3602 static type_t *automatic_type_conversion(type_t *orig_type);
3603
3604 static type_t *semantic_parameter(const position_t *pos, type_t *type,
3605                                   const declaration_specifiers_t *specifiers,
3606                                   entity_t const *const param)
3607 {
3608         /* §6.7.5.3:7  A declaration of a parameter as ``array of type''
3609          *             shall be adjusted to ``qualified pointer to type'',
3610          *             [...]
3611          * §6.7.5.3:8  A declaration of a parameter as ``function returning
3612          *             type'' shall be adjusted to ``pointer to function
3613          *             returning type'', as in 6.3.2.1. */
3614         type = automatic_type_conversion(type);
3615
3616         if (specifiers->is_inline && is_type_valid(type)) {
3617                 errorf(pos, "'%N' declared 'inline'", param);
3618         }
3619
3620         /* §6.9.1:6  The declarations in the declaration list shall contain
3621          *           no storage-class specifier other than register and no
3622          *           initializations. */
3623         if (specifiers->thread_local || (
3624                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3625                         specifiers->storage_class != STORAGE_CLASS_REGISTER)
3626            ) {
3627                 errorf(pos, "invalid storage class for '%N'", param);
3628         }
3629
3630         /* delay test for incomplete type, because we might have (void)
3631          * which is legal but incomplete... */
3632
3633         return type;
3634 }
3635
3636 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
3637                                   declarator_flags_t flags)
3638 {
3639         parse_declarator_env_t env;
3640         memset(&env, 0, sizeof(env));
3641         env.may_be_abstract = (flags & DECL_MAY_BE_ABSTRACT) != 0;
3642
3643         construct_type_t *construct_type = parse_inner_declarator(&env);
3644         type_t           *orig_type      =
3645                 construct_declarator_type(construct_type, specifiers->type);
3646         type_t           *type           = skip_typeref(orig_type);
3647
3648         if (construct_type != NULL) {
3649                 obstack_free(&temp_obst, construct_type);
3650         }
3651
3652         attribute_t *attributes = parse_attributes(env.attributes);
3653         /* append (shared) specifier attribute behind attributes of this
3654          * declarator */
3655         attribute_t **anchor = &attributes;
3656         while (*anchor != NULL)
3657                 anchor = &(*anchor)->next;
3658         *anchor = specifiers->attributes;
3659
3660         entity_t *entity;
3661         if (specifiers->storage_class == STORAGE_CLASS_TYPEDEF) {
3662                 entity = allocate_entity_zero(ENTITY_TYPEDEF, NAMESPACE_NORMAL, env.symbol, &env.pos);
3663                 entity->typedefe.type = orig_type;
3664
3665                 if (anonymous_entity != NULL) {
3666                         if (is_type_compound(type)) {
3667                                 assert(anonymous_entity->compound.alias == NULL);
3668                                 assert(anonymous_entity->kind == ENTITY_STRUCT ||
3669                                        anonymous_entity->kind == ENTITY_UNION);
3670                                 anonymous_entity->compound.alias = entity;
3671                                 anonymous_entity = NULL;
3672                         } else if (is_type_enum(type)) {
3673                                 assert(anonymous_entity->enume.alias == NULL);
3674                                 assert(anonymous_entity->kind == ENTITY_ENUM);
3675                                 anonymous_entity->enume.alias = entity;
3676                                 anonymous_entity = NULL;
3677                         }
3678                 }
3679         } else {
3680                 /* create a declaration type entity */
3681                 position_t const *const pos = env.symbol ? &env.pos : &specifiers->pos;
3682                 if (flags & DECL_CREATE_COMPOUND_MEMBER) {
3683                         entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, env.symbol, pos);
3684
3685                         if (env.symbol != NULL) {
3686                                 if (specifiers->is_inline && is_type_valid(type)) {
3687                                         errorf(&env.pos, "'%N' declared 'inline'", entity);
3688                                 }
3689
3690                                 if (specifiers->thread_local ||
3691                                                 specifiers->storage_class != STORAGE_CLASS_NONE) {
3692                                         errorf(&env.pos, "'%N' must have no storage class", entity);
3693                                 }
3694                         }
3695                 } else if (flags & DECL_IS_PARAMETER) {
3696                         entity    = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, env.symbol, pos);
3697                         orig_type = semantic_parameter(&env.pos, orig_type, specifiers, entity);
3698                 } else if (is_type_function(type)) {
3699                         entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, env.symbol, pos);
3700                         entity->function.is_inline      = specifiers->is_inline;
3701                         entity->function.elf_visibility = default_visibility;
3702                         entity->function.parameters     = env.parameters;
3703
3704                         if (env.symbol != NULL) {
3705                                 /* this needs fixes for C++ */
3706                                 bool in_function_scope = current_function != NULL;
3707
3708                                 if (specifiers->thread_local || (
3709                                                         specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3710                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3711                                                         (in_function_scope || specifiers->storage_class != STORAGE_CLASS_STATIC)
3712                                                 )) {
3713                                         errorf(&env.pos, "invalid storage class for '%N'", entity);
3714                                 }
3715                         }
3716                 } else {
3717                         entity = allocate_entity_zero(ENTITY_VARIABLE, NAMESPACE_NORMAL, env.symbol, pos);
3718                         entity->variable.elf_visibility = default_visibility;
3719                         entity->variable.thread_local   = specifiers->thread_local;
3720
3721                         if (env.symbol != NULL) {
3722                                 if (specifiers->is_inline && is_type_valid(type)) {
3723                                         errorf(&env.pos, "'%N' declared 'inline'", entity);
3724                                 }
3725
3726                                 bool invalid_storage_class = false;
3727                                 if (current_scope == file_scope) {
3728                                         if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3729                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3730                                                         specifiers->storage_class != STORAGE_CLASS_STATIC) {
3731                                                 invalid_storage_class = true;
3732                                         }
3733                                 } else {
3734                                         if (specifiers->thread_local &&
3735                                                         specifiers->storage_class == STORAGE_CLASS_NONE) {
3736                                                 invalid_storage_class = true;
3737                                         }
3738                                 }
3739                                 if (invalid_storage_class) {
3740                                         errorf(&env.pos, "invalid storage class for '%N'", entity);
3741                                 }
3742                         }
3743                 }
3744
3745                 entity->declaration.type       = orig_type;
3746                 entity->declaration.alignment  = get_type_alignment(orig_type);
3747                 entity->declaration.modifiers  = env.modifiers;
3748                 entity->declaration.attributes = attributes;
3749
3750                 storage_class_t storage_class = specifiers->storage_class;
3751                 entity->declaration.declared_storage_class = storage_class;
3752
3753                 if (storage_class == STORAGE_CLASS_NONE && current_function != NULL)
3754                         storage_class = STORAGE_CLASS_AUTO;
3755                 entity->declaration.storage_class = storage_class;
3756         }
3757
3758         if (attributes != NULL) {
3759                 handle_entity_attributes(attributes, entity);
3760         }
3761
3762         if (entity->kind == ENTITY_FUNCTION && !freestanding) {
3763                 adapt_special_functions(&entity->function);
3764         }
3765
3766         return entity;
3767 }
3768
3769 static type_t *parse_abstract_declarator(type_t *base_type)
3770 {
3771         parse_declarator_env_t env;
3772         memset(&env, 0, sizeof(env));
3773         env.may_be_abstract = true;
3774         env.must_be_abstract = true;
3775
3776         construct_type_t *construct_type = parse_inner_declarator(&env);
3777
3778         type_t *result = construct_declarator_type(construct_type, base_type);
3779         if (construct_type != NULL) {
3780                 obstack_free(&temp_obst, construct_type);
3781         }
3782         result = handle_type_attributes(env.attributes, result);
3783
3784         return result;
3785 }
3786
3787 /**
3788  * Check if the declaration of main is suspicious.  main should be a
3789  * function with external linkage, returning int, taking either zero
3790  * arguments, two, or three arguments of appropriate types, ie.
3791  *
3792  * int main([ int argc, char **argv [, char **env ] ]).
3793  *
3794  * @param decl    the declaration to check
3795  * @param type    the function type of the declaration
3796  */
3797 static void check_main(const entity_t *entity)
3798 {
3799         const position_t *pos = &entity->base.pos;
3800         if (entity->kind != ENTITY_FUNCTION) {
3801                 warningf(WARN_MAIN, pos, "'main' is not a function");
3802                 return;
3803         }
3804
3805         if (entity->declaration.storage_class == STORAGE_CLASS_STATIC) {
3806                 warningf(WARN_MAIN, pos, "'main' is normally a non-static function");
3807         }
3808
3809         type_t *type = skip_typeref(entity->declaration.type);
3810         assert(is_type_function(type));
3811
3812         function_type_t const *const func_type = &type->function;
3813         type_t                *const ret_type  = func_type->return_type;
3814         if (!types_compatible(skip_typeref(ret_type), type_int)) {
3815                 warningf(WARN_MAIN, pos, "return type of 'main' should be 'int', but is '%T'", ret_type);
3816         }
3817         const function_parameter_t *parm = func_type->parameters;
3818         if (parm != NULL) {
3819                 type_t *const first_type        = skip_typeref(parm->type);
3820                 type_t *const first_type_unqual = get_unqualified_type(first_type);
3821                 if (!types_compatible(first_type_unqual, type_int)) {
3822                         warningf(WARN_MAIN, pos, "first argument of 'main' should be 'int', but is '%T'", parm->type);
3823                 }
3824                 parm = parm->next;
3825                 if (parm != NULL) {
3826                         type_t *const second_type = skip_typeref(parm->type);
3827                         type_t *const second_type_unqual
3828                                 = get_unqualified_type(second_type);
3829                         if (!types_compatible(second_type_unqual, type_char_ptr_ptr)) {
3830                                 warningf(WARN_MAIN, pos, "second argument of 'main' should be 'char**', but is '%T'", parm->type);
3831                         }
3832                         parm = parm->next;
3833                         if (parm != NULL) {
3834                                 type_t *const third_type = skip_typeref(parm->type);
3835                                 type_t *const third_type_unqual
3836                                         = get_unqualified_type(third_type);
3837                                 if (!types_compatible(third_type_unqual, type_char_ptr_ptr)) {
3838                                         warningf(WARN_MAIN, pos, "third argument of 'main' should be 'char**', but is '%T'", parm->type);
3839                                 }
3840                                 parm = parm->next;
3841                                 if (parm != NULL)
3842                                         goto warn_arg_count;
3843                         }
3844                 } else {
3845 warn_arg_count:
3846                         warningf(WARN_MAIN, pos, "'main' takes only zero, two or three arguments");
3847                 }
3848         }
3849 }
3850
3851 static void error_redefined_as_different_kind(const position_t *pos,
3852                 const entity_t *old, entity_kind_t new_kind)
3853 {
3854         char       const *const what = get_entity_kind_name(new_kind);
3855         position_t const *const ppos = &old->base.pos;
3856         errorf(pos, "redeclaration of '%N' as %s (declared %P)", old, what, ppos);
3857 }
3858
3859 static bool is_entity_valid(entity_t *const ent)
3860 {
3861         if (is_declaration(ent)) {
3862                 return is_type_valid(skip_typeref(ent->declaration.type));
3863         } else if (ent->kind == ENTITY_TYPEDEF) {
3864                 return is_type_valid(skip_typeref(ent->typedefe.type));
3865         }
3866         return true;
3867 }
3868
3869 static bool contains_attribute(const attribute_t *list, const attribute_t *attr)
3870 {
3871         for (const attribute_t *tattr = list; tattr != NULL; tattr = tattr->next) {
3872                 if (attributes_equal(tattr, attr))
3873                         return true;
3874         }
3875         return false;
3876 }
3877
3878 /**
3879  * Tests whether new_list contains any attributes not included in old_list
3880  */
3881 static bool has_new_attributes(const attribute_t *old_list,
3882                                const attribute_t *new_list)
3883 {
3884         for (const attribute_t *attr = new_list; attr != NULL; attr = attr->next) {
3885                 if (!contains_attribute(old_list, attr))
3886                         return true;
3887         }
3888         return false;
3889 }
3890
3891 /**
3892  * Merge in attributes from an attribute list (probably from a previous
3893  * declaration with the same name). Warning: destroys the old structure
3894  * of the attribute list - don't reuse attributes after this call.
3895  */
3896 static void merge_in_attributes(declaration_t *decl, attribute_t *attributes)
3897 {
3898         attribute_t *next;
3899         for (attribute_t *attr = attributes; attr != NULL; attr = next) {
3900                 next = attr->next;
3901                 if (contains_attribute(decl->attributes, attr))
3902                         continue;
3903
3904                 /* move attribute to new declarations attributes list */
3905                 attr->next       = decl->attributes;
3906                 decl->attributes = attr;
3907         }
3908 }
3909
3910 static bool is_main(entity_t*);
3911
3912 /**
3913  * record entities for the NAMESPACE_NORMAL, and produce error messages/warnings
3914  * for various problems that occur for multiple definitions
3915  */
3916 entity_t *record_entity(entity_t *entity, const bool is_definition)
3917 {
3918         const symbol_t *const symbol  = entity->base.symbol;
3919         const namespace_tag_t namespc = (namespace_tag_t)entity->base.namespc;
3920         const position_t     *pos     = &entity->base.pos;
3921
3922         /* can happen in error cases */
3923         if (symbol == NULL)
3924                 return entity;
3925
3926         assert(!entity->base.parent_scope);
3927         assert(current_scope);
3928         entity->base.parent_scope = current_scope;
3929
3930         entity_t *const previous_entity = get_entity(symbol, namespc);
3931         /* pushing the same entity twice will break the stack structure */
3932         assert(previous_entity != entity);
3933
3934         if (entity->kind == ENTITY_FUNCTION) {
3935                 type_t *const orig_type = entity->declaration.type;
3936                 type_t *const type      = skip_typeref(orig_type);
3937
3938                 assert(is_type_function(type));
3939                 if (type->function.unspecified_parameters &&
3940                     previous_entity == NULL               &&
3941                     !entity->declaration.implicit) {
3942                         warningf(WARN_STRICT_PROTOTYPES, pos, "function declaration '%#N' is not a prototype", entity);
3943                 }
3944
3945                 if (is_main(entity)) {
3946                         check_main(entity);
3947                 }
3948         }
3949
3950         if (is_declaration(entity)                                    &&
3951             entity->declaration.storage_class == STORAGE_CLASS_EXTERN &&
3952             current_scope != file_scope                               &&
3953             !entity->declaration.implicit) {
3954                 warningf(WARN_NESTED_EXTERNS, pos, "nested extern declaration of '%#N'", entity);
3955         }
3956
3957         if (previous_entity != NULL) {
3958                 position_t const *const ppos = &previous_entity->base.pos;
3959
3960                 if (previous_entity->base.parent_scope == &current_function->parameters &&
3961                                 previous_entity->base.parent_scope->depth + 1 == current_scope->depth) {
3962                         assert(previous_entity->kind == ENTITY_PARAMETER);
3963                         errorf(pos, "declaration of '%N' redeclares the '%N' (declared %P)", entity, previous_entity, ppos);
3964                         goto finish;
3965                 }
3966
3967                 if (previous_entity->base.parent_scope == current_scope) {
3968                         if (previous_entity->kind != entity->kind) {
3969                                 if (is_entity_valid(previous_entity) && is_entity_valid(entity)) {
3970                                         error_redefined_as_different_kind(pos, previous_entity,
3971                                                         entity->kind);
3972                                 }
3973                                 goto finish;
3974                         }
3975                         if (previous_entity->kind == ENTITY_ENUM_VALUE) {
3976                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
3977                                 goto finish;
3978                         }
3979                         if (previous_entity->kind == ENTITY_TYPEDEF) {
3980                                 type_t *const type      = skip_typeref(entity->typedefe.type);
3981                                 type_t *const prev_type
3982                                         = skip_typeref(previous_entity->typedefe.type);
3983                                 if (c_mode & _CXX) {
3984                                         /* C++ allows double typedef if they are identical
3985                                          * (after skipping typedefs) */
3986                                         if (type == prev_type)
3987                                                 goto finish;
3988                                 } else {
3989                                         /* GCC extension: redef in system headers is allowed */
3990                                         if ((pos->is_system_header || ppos->is_system_header) &&
3991                                             types_compatible(type, prev_type))
3992                                                 goto finish;
3993                                 }
3994                                 errorf(pos, "redefinition of '%N' (declared %P)",
3995                                        entity, ppos);
3996                                 goto finish;
3997                         }
3998
3999                         /* at this point we should have only VARIABLES or FUNCTIONS */
4000                         assert(is_declaration(previous_entity) && is_declaration(entity));
4001
4002                         declaration_t *const prev_decl = &previous_entity->declaration;
4003                         declaration_t *const decl      = &entity->declaration;
4004
4005                         /* can happen for K&R style declarations */
4006                         if (prev_decl->type       == NULL             &&
4007                                         previous_entity->kind == ENTITY_PARAMETER &&
4008                                         entity->kind          == ENTITY_PARAMETER) {
4009                                 prev_decl->type                   = decl->type;
4010                                 prev_decl->storage_class          = decl->storage_class;
4011                                 prev_decl->declared_storage_class = decl->declared_storage_class;
4012                                 prev_decl->modifiers              = decl->modifiers;
4013                                 return previous_entity;
4014                         }
4015
4016                         type_t *const type      = skip_typeref(decl->type);
4017                         type_t *const prev_type = skip_typeref(prev_decl->type);
4018
4019                         if (!types_compatible(type, prev_type)) {
4020                                 errorf(pos, "declaration '%#N' is incompatible with '%#N' (declared %P)", entity, previous_entity, ppos);
4021                         } else {
4022                                 unsigned old_storage_class = prev_decl->storage_class;
4023
4024                                 if (is_definition                     &&
4025                                                 !prev_decl->used                  &&
4026                                                 !(prev_decl->modifiers & DM_USED) &&
4027                                                 prev_decl->storage_class == STORAGE_CLASS_STATIC) {
4028                                         warningf(WARN_REDUNDANT_DECLS, ppos, "unnecessary static forward declaration for '%#N'", previous_entity);
4029                                 }
4030
4031                                 storage_class_t new_storage_class = decl->storage_class;
4032
4033                                 /* pretend no storage class means extern for function
4034                                  * declarations (except if the previous declaration is neither
4035                                  * none nor extern) */
4036                                 if (entity->kind == ENTITY_FUNCTION) {
4037                                         /* the previous declaration could have unspecified parameters or
4038                                          * be a typedef, so use the new type */
4039                                         if (prev_type->function.unspecified_parameters || is_definition)
4040                                                 prev_decl->type = type;
4041
4042                                         switch (old_storage_class) {
4043                                                 case STORAGE_CLASS_NONE:
4044                                                         old_storage_class = STORAGE_CLASS_EXTERN;
4045                                                         /* FALLTHROUGH */
4046
4047                                                 case STORAGE_CLASS_EXTERN:
4048                                                         if (is_definition) {
4049                                                                 if (prev_type->function.unspecified_parameters && !is_main(entity)) {
4050                                                                         warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4051                                                                 }
4052                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
4053                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
4054                                                         }
4055                                                         break;
4056
4057                                                 default:
4058                                                         break;
4059                                         }
4060                                 } else if (is_type_incomplete(prev_type)) {
4061                                         prev_decl->type = type;
4062                                 }
4063
4064                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
4065                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
4066
4067 warn_redundant_declaration: ;
4068                                         bool has_new_attrs
4069                                                 = has_new_attributes(prev_decl->attributes,
4070                                                                      decl->attributes);
4071                                         if (has_new_attrs) {
4072                                                 merge_in_attributes(decl, prev_decl->attributes);
4073                                         } else if (!is_definition && is_type_valid(prev_type)) {
4074                                                 warningf(WARN_REDUNDANT_DECLS, pos, "redundant declaration for '%N' (declared %P)", entity, ppos);
4075                                         }
4076                                 } else if (current_function == NULL) {
4077                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
4078                                                         new_storage_class == STORAGE_CLASS_STATIC) {
4079                                                 errorf(pos, "static declaration of '%N' follows non-static declaration (declared %P)", entity, ppos);
4080                                         } else if (old_storage_class == STORAGE_CLASS_EXTERN) {
4081                                                 prev_decl->storage_class          = STORAGE_CLASS_NONE;
4082                                                 prev_decl->declared_storage_class = STORAGE_CLASS_NONE;
4083                                         } else {
4084                                                 /* ISO/IEC 14882:1998(E) §C.1.2:1 */
4085                                                 if (c_mode & _CXX)
4086                                                         goto error_redeclaration;
4087                                                 goto warn_redundant_declaration;
4088                                         }
4089                                 } else if (is_type_valid(prev_type)) {
4090                                         if (old_storage_class == new_storage_class) {
4091 error_redeclaration:
4092                                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4093                                         } else {
4094                                                 errorf(pos, "redeclaration of '%N' with different linkage (declared %P)", entity, ppos);
4095                                         }
4096                                 }
4097                         }
4098
4099                         prev_decl->modifiers |= decl->modifiers;
4100                         if (entity->kind == ENTITY_FUNCTION) {
4101                                 previous_entity->function.is_inline |= entity->function.is_inline;
4102                         }
4103                         return previous_entity;
4104                 }
4105
4106                 warning_t why;
4107                 if (is_warn_on(why = WARN_SHADOW) ||
4108                     (is_warn_on(why = WARN_SHADOW_LOCAL) && previous_entity->base.parent_scope != file_scope)) {
4109                         char const *const what = get_entity_kind_name(previous_entity->kind);
4110                         warningf(why, pos, "'%N' shadows %s (declared %P)", entity, what, ppos);
4111                 }
4112         }
4113
4114         if (entity->kind == ENTITY_FUNCTION) {
4115                 if (is_definition &&
4116                                 entity->declaration.storage_class != STORAGE_CLASS_STATIC &&
4117                                 !is_main(entity)) {
4118                         if (is_warn_on(WARN_MISSING_PROTOTYPES)) {
4119                                 warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4120                         } else {
4121                                 goto warn_missing_declaration;
4122                         }
4123                 }
4124         } else if (entity->kind == ENTITY_VARIABLE) {
4125                 if (current_scope                     == file_scope &&
4126                     entity->declaration.storage_class == STORAGE_CLASS_NONE &&
4127                     !entity->declaration.implicit) {
4128 warn_missing_declaration:
4129                         if (is_type_valid(skip_typeref(entity->declaration.type)))
4130                                 warningf(WARN_MISSING_DECLARATIONS, pos, "no previous declaration for '%#N'", entity);
4131                 }
4132         }
4133
4134 finish:
4135         environment_push(entity);
4136         append_entity(current_scope, entity);
4137
4138         return entity;
4139 }
4140
4141 static void parser_error_multiple_definition(entity_t *entity,
4142                                              const position_t *pos)
4143 {
4144         errorf(pos, "redefinition of '%N' (declared %P)", entity, &entity->base.pos);
4145 }
4146
4147 static bool is_declaration_specifier(token_t const *const tk)
4148 {
4149         switch (tk->kind) {
4150                 DECLARATION_START
4151                         return true;
4152                 case T_IDENTIFIER:
4153                         return is_typedef_symbol(tk->base.symbol);
4154
4155                 default:
4156                         return false;
4157         }
4158 }
4159
4160 static void parse_init_declarator_rest(entity_t *entity)
4161 {
4162         type_t *orig_type = type_error_type;
4163
4164         if (entity->base.kind == ENTITY_TYPEDEF) {
4165                 position_t const *const pos = &entity->base.pos;
4166                 errorf(pos, "'%N' is initialized (use __typeof__ instead)", entity);
4167         } else {
4168                 assert(is_declaration(entity));
4169                 orig_type = entity->declaration.type;
4170         }
4171
4172         type_t *type = skip_typeref(orig_type);
4173
4174         if (entity->kind == ENTITY_VARIABLE
4175                         && entity->variable.initializer != NULL) {
4176                 parser_error_multiple_definition(entity, HERE);
4177         }
4178         eat('=');
4179
4180         declaration_t *const declaration = &entity->declaration;
4181         bool must_be_constant = false;
4182         if (declaration->storage_class == STORAGE_CLASS_STATIC ||
4183             entity->base.parent_scope  == file_scope) {
4184                 must_be_constant = true;
4185         }
4186
4187         if (is_type_function(type)) {
4188                 position_t const *const pos = &entity->base.pos;
4189                 errorf(pos, "'%N' is initialized like a variable", entity);
4190                 orig_type = type_error_type;
4191         }
4192
4193         parse_initializer_env_t env;
4194         env.type             = orig_type;
4195         env.must_be_constant = must_be_constant;
4196         env.entity           = entity;
4197
4198         initializer_t *initializer = parse_initializer(&env);
4199
4200         if (entity->kind == ENTITY_VARIABLE) {
4201                 /* §6.7.5:22  array initializers for arrays with unknown size
4202                  * determine the array type size */
4203                 declaration->type            = env.type;
4204                 entity->variable.initializer = initializer;
4205         }
4206 }
4207
4208 /* parse rest of a declaration without any declarator */
4209 static void parse_anonymous_declaration_rest(
4210                 const declaration_specifiers_t *specifiers)
4211 {
4212         eat(';');
4213         anonymous_entity = NULL;
4214
4215         position_t const *const pos = &specifiers->pos;
4216         if (specifiers->storage_class != STORAGE_CLASS_NONE ||
4217                         specifiers->thread_local) {
4218                 warningf(WARN_OTHER, pos, "useless storage class in empty declaration");
4219         }
4220
4221         type_t *type = specifiers->type;
4222         switch (type->kind) {
4223                 case TYPE_COMPOUND_STRUCT:
4224                 case TYPE_COMPOUND_UNION: {
4225                         if (type->compound.compound->base.symbol == NULL) {
4226                                 warningf(WARN_OTHER, pos, "unnamed struct/union that defines no instances");
4227                         }
4228                         break;
4229                 }
4230
4231                 case TYPE_ENUM:
4232                         break;
4233
4234                 default:
4235                         warningf(WARN_OTHER, pos, "empty declaration");
4236                         break;
4237         }
4238 }
4239
4240 static void check_variable_type_complete(entity_t *ent)
4241 {
4242         if (ent->kind != ENTITY_VARIABLE)
4243                 return;
4244
4245         /* §6.7:7  If an identifier for an object is declared with no linkage, the
4246          *         type for the object shall be complete [...] */
4247         declaration_t *decl = &ent->declaration;
4248         if (decl->storage_class == STORAGE_CLASS_EXTERN ||
4249                         decl->storage_class == STORAGE_CLASS_STATIC)
4250                 return;
4251
4252         type_t *const type = skip_typeref(decl->type);
4253         if (!is_type_incomplete(type))
4254                 return;
4255
4256         /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
4257          * are given length one. */
4258         if (is_type_array(type) && ent->base.parent_scope == file_scope) {
4259                 ARR_APP1(declaration_t*, incomplete_arrays, decl);
4260                 return;
4261         }
4262
4263         errorf(&ent->base.pos, "variable '%#N' has incomplete type", ent);
4264 }
4265
4266
4267 static void parse_declaration_rest(entity_t *ndeclaration,
4268                 const declaration_specifiers_t *specifiers,
4269                 parsed_declaration_func         finished_declaration,
4270                 declarator_flags_t              flags)
4271 {
4272         add_anchor_token(';');
4273         add_anchor_token(',');
4274         while (true) {
4275                 entity_t *entity = finished_declaration(ndeclaration, token.kind == '=');
4276
4277                 if (token.kind == '=') {
4278                         parse_init_declarator_rest(entity);
4279                 } else if (entity->kind == ENTITY_VARIABLE) {
4280                         /* ISO/IEC 14882:1998(E) §8.5.3:3  The initializer can be omitted
4281                          * [...] where the extern specifier is explicitly used. */
4282                         declaration_t *decl = &entity->declaration;
4283                         if (decl->storage_class != STORAGE_CLASS_EXTERN &&
4284                             is_type_reference(skip_typeref(decl->type))) {
4285                                 position_t const *const pos = &entity->base.pos;
4286                                 errorf(pos, "reference '%#N' must be initialized", entity);
4287                         }
4288                 }
4289
4290                 check_variable_type_complete(entity);
4291
4292                 if (!accept(','))
4293                         break;
4294
4295                 add_anchor_token('=');
4296                 ndeclaration = parse_declarator(specifiers, flags);
4297                 rem_anchor_token('=');
4298         }
4299         rem_anchor_token(',');
4300         rem_anchor_token(';');
4301         expect(';');
4302
4303         anonymous_entity = NULL;
4304 }
4305
4306 static entity_t *finished_kr_declaration(entity_t *entity, bool is_definition)
4307 {
4308         symbol_t *symbol = entity->base.symbol;
4309         if (symbol == NULL)
4310                 return entity;
4311
4312         assert(entity->base.namespc == NAMESPACE_NORMAL);
4313         entity_t *previous_entity = get_entity(symbol, NAMESPACE_NORMAL);
4314         if (previous_entity == NULL
4315                         || previous_entity->base.parent_scope != current_scope) {
4316                 errorf(&entity->base.pos, "expected declaration of a function parameter, found '%Y'",
4317                        symbol);
4318                 return entity;
4319         }
4320
4321         if (is_definition) {
4322                 errorf(HERE, "'%N' is initialised", entity);
4323         }
4324
4325         return record_entity(entity, false);
4326 }
4327
4328 static void parse_declaration(parsed_declaration_func finished_declaration,
4329                               declarator_flags_t      flags)
4330 {
4331         add_anchor_token(';');
4332         declaration_specifiers_t specifiers;
4333         parse_declaration_specifiers(&specifiers);
4334         rem_anchor_token(';');
4335
4336         if (token.kind == ';') {
4337                 parse_anonymous_declaration_rest(&specifiers);
4338         } else {
4339                 entity_t *entity = parse_declarator(&specifiers, flags);
4340                 parse_declaration_rest(entity, &specifiers, finished_declaration, flags);
4341         }
4342 }
4343
4344 /* §6.5.2.2:6 */
4345 static type_t *get_default_promoted_type(type_t *orig_type)
4346 {
4347         type_t *result = orig_type;
4348
4349         type_t *type = skip_typeref(orig_type);
4350         if (is_type_integer(type)) {
4351                 result = promote_integer(type);
4352         } else if (is_type_atomic(type, ATOMIC_TYPE_FLOAT)) {
4353                 result = type_double;
4354         }
4355
4356         return result;
4357 }
4358
4359 static void parse_kr_declaration_list(entity_t *entity)
4360 {
4361         if (entity->kind != ENTITY_FUNCTION)
4362                 return;
4363
4364         type_t *type = skip_typeref(entity->declaration.type);
4365         assert(is_type_function(type));
4366         if (!type->function.kr_style_parameters)
4367                 return;
4368
4369         add_anchor_token('{');
4370
4371         PUSH_SCOPE(&entity->function.parameters);
4372
4373         entity_t *parameter = entity->function.parameters.entities;
4374         for ( ; parameter != NULL; parameter = parameter->base.next) {
4375                 assert(parameter->base.parent_scope == NULL);
4376                 parameter->base.parent_scope = current_scope;
4377                 environment_push(parameter);
4378         }
4379
4380         /* parse declaration list */
4381         for (;;) {
4382                 switch (token.kind) {
4383                         DECLARATION_START
4384                         /* This covers symbols, which are no type, too, and results in
4385                          * better error messages.  The typical cases are misspelled type
4386                          * names and missing includes. */
4387                         case T_IDENTIFIER:
4388                                 parse_declaration(finished_kr_declaration, DECL_IS_PARAMETER);
4389                                 break;
4390                         default:
4391                                 goto decl_list_end;
4392                 }
4393         }
4394 decl_list_end:
4395
4396         POP_SCOPE();
4397
4398         /* update function type */
4399         type_t *new_type = duplicate_type(type);
4400
4401         function_parameter_t  *parameters = NULL;
4402         function_parameter_t **anchor     = &parameters;
4403
4404         /* did we have an earlier prototype? */
4405         entity_t *proto_type = get_entity(entity->base.symbol, NAMESPACE_NORMAL);
4406         if (proto_type != NULL && proto_type->kind != ENTITY_FUNCTION)
4407                 proto_type = NULL;
4408
4409         function_parameter_t *proto_parameter = NULL;
4410         if (proto_type != NULL) {
4411                 type_t *proto_type_type = proto_type->declaration.type;
4412                 proto_parameter         = proto_type_type->function.parameters;
4413                 /* If a K&R function definition has a variadic prototype earlier, then
4414                  * make the function definition variadic, too. This should conform to
4415                  * §6.7.5.3:15 and §6.9.1:8. */
4416                 new_type->function.variadic = proto_type_type->function.variadic;
4417         } else {
4418                 /* §6.9.1.7: A K&R style parameter list does NOT act as a function
4419                  * prototype */
4420                 new_type->function.unspecified_parameters = true;
4421         }
4422
4423         bool need_incompatible_warning = false;
4424         parameter = entity->function.parameters.entities;
4425         for (; parameter != NULL; parameter = parameter->base.next,
4426                         proto_parameter =
4427                                 proto_parameter == NULL ? NULL : proto_parameter->next) {
4428                 if (parameter->kind != ENTITY_PARAMETER)
4429                         continue;
4430
4431                 type_t *parameter_type = parameter->declaration.type;
4432                 if (parameter_type == NULL) {
4433                         position_t const* const pos = &parameter->base.pos;
4434                         if (strict_mode) {
4435                                 errorf(pos, "no type specified for function '%N'", parameter);
4436                                 parameter_type = type_error_type;
4437                         } else {
4438                                 warningf(WARN_IMPLICIT_INT, pos, "no type specified for function parameter '%N', using 'int'", parameter);
4439                                 parameter_type = type_int;
4440                         }
4441                         parameter->declaration.type = parameter_type;
4442                 }
4443
4444                 semantic_parameter_incomplete(parameter);
4445
4446                 /* we need the default promoted types for the function type */
4447                 type_t *not_promoted = parameter_type;
4448                 parameter_type       = get_default_promoted_type(parameter_type);
4449
4450                 /* gcc special: if the type of the prototype matches the unpromoted
4451                  * type don't promote */
4452                 if (!strict_mode && proto_parameter != NULL) {
4453                         type_t *proto_p_type = skip_typeref(proto_parameter->type);
4454                         type_t *promo_skip   = skip_typeref(parameter_type);
4455                         type_t *param_skip   = skip_typeref(not_promoted);
4456                         if (!types_compatible(proto_p_type, promo_skip)
4457                                 && types_compatible(proto_p_type, param_skip)) {
4458                                 /* don't promote */
4459                                 need_incompatible_warning = true;
4460                                 parameter_type = not_promoted;
4461                         }
4462                 }
4463                 function_parameter_t *const function_parameter
4464                         = allocate_parameter(parameter_type);
4465
4466                 *anchor = function_parameter;
4467                 anchor  = &function_parameter->next;
4468         }
4469
4470         new_type->function.parameters = parameters;
4471         new_type = identify_new_type(new_type);
4472
4473         if (need_incompatible_warning) {
4474                 symbol_t   const *const sym  = entity->base.symbol;
4475                 position_t const *const pos  = &entity->base.pos;
4476                 position_t const *const ppos = &proto_type->base.pos;
4477                 warningf(WARN_OTHER, pos, "declaration '%#N' is incompatible with '%#T' (declared %P)", proto_type, new_type, sym, ppos);
4478         }
4479         entity->declaration.type = new_type;
4480
4481         rem_anchor_token('{');
4482 }
4483
4484 static bool first_err = true;
4485
4486 /**
4487  * When called with first_err set, prints the name of the current function,
4488  * else does noting.
4489  */
4490 static void print_in_function(void)
4491 {
4492         if (first_err) {
4493                 first_err = false;
4494                 char const *const file = current_function->base.base.pos.input_name;
4495                 diagnosticf("%s: In '%N':\n", file, (entity_t const*)current_function);
4496         }
4497 }
4498
4499 /**
4500  * Check if all labels are defined in the current function.
4501  * Check if all labels are used in the current function.
4502  */
4503 static void check_labels(void)
4504 {
4505         for (const goto_statement_t *goto_statement = goto_first;
4506             goto_statement != NULL;
4507             goto_statement = goto_statement->next) {
4508                 label_t *label = goto_statement->label;
4509                 if (label->base.pos.input_name == NULL) {
4510                         print_in_function();
4511                         position_t const *const pos = &goto_statement->base.pos;
4512                         errorf(pos, "'%N' used but not defined", (entity_t const*)label);
4513                  }
4514         }
4515
4516         if (is_warn_on(WARN_UNUSED_LABEL)) {
4517                 for (const label_statement_t *label_statement = label_first;
4518                          label_statement != NULL;
4519                          label_statement = label_statement->next) {
4520                         label_t *label = label_statement->label;
4521
4522                         if (! label->used) {
4523                                 print_in_function();
4524                                 position_t const *const pos = &label_statement->base.pos;
4525                                 warningf(WARN_UNUSED_LABEL, pos, "'%N' defined but not used", (entity_t const*)label);
4526                         }
4527                 }
4528         }
4529 }
4530
4531 static void warn_unused_entity(warning_t const why, entity_t *entity, entity_t *const last)
4532 {
4533         entity_t const *const end = last != NULL ? last->base.next : NULL;
4534         for (; entity != end; entity = entity->base.next) {
4535                 if (!is_declaration(entity))
4536                         continue;
4537
4538                 declaration_t *declaration = &entity->declaration;
4539                 if (declaration->implicit)
4540                         continue;
4541
4542                 if (!declaration->used) {
4543                         print_in_function();
4544                         warningf(why, &entity->base.pos, "'%N' is unused", entity);
4545                 } else if (entity->kind == ENTITY_VARIABLE && !entity->variable.read) {
4546                         print_in_function();
4547                         warningf(why, &entity->base.pos, "'%N' is never read", entity);
4548                 }
4549         }
4550 }
4551
4552 static void check_unused_variables(statement_t *const stmt, void *const env)
4553 {
4554         (void)env;
4555
4556         switch (stmt->kind) {
4557                 case STATEMENT_DECLARATION: {
4558                         declaration_statement_t const *const decls = &stmt->declaration;
4559                         warn_unused_entity(WARN_UNUSED_VARIABLE, decls->declarations_begin, decls->declarations_end);
4560                         return;
4561                 }
4562
4563                 case STATEMENT_FOR:
4564                         warn_unused_entity(WARN_UNUSED_VARIABLE, stmt->fors.scope.entities, NULL);
4565                         return;
4566
4567                 default:
4568                         return;
4569         }
4570 }
4571
4572 /**
4573  * Check declarations of current_function for unused entities.
4574  */
4575 static void check_declarations(void)
4576 {
4577         if (is_warn_on(WARN_UNUSED_PARAMETER)) {
4578                 const scope_t *scope = &current_function->parameters;
4579                 warn_unused_entity(WARN_UNUSED_PARAMETER, scope->entities, NULL);
4580         }
4581         if (is_warn_on(WARN_UNUSED_VARIABLE)) {
4582                 walk_statements(current_function->body, check_unused_variables, NULL);
4583         }
4584 }
4585
4586 static int determine_truth(expression_t const* const cond)
4587 {
4588         return
4589                 is_constant_expression(cond) < EXPR_CLASS_CONSTANT ? 0 :
4590                 fold_constant_to_bool(cond)                        ? 1 :
4591                 -1;
4592 }
4593
4594 static void check_reachable(statement_t *);
4595 static bool reaches_end;
4596
4597 static bool expression_returns(expression_t const *const expr)
4598 {
4599         switch (expr->kind) {
4600                 case EXPR_CALL: {
4601                         expression_t const *const func = expr->call.function;
4602                         type_t       const *const type = skip_typeref(func->base.type);
4603                         if (type->kind == TYPE_POINTER) {
4604                                 type_t const *const points_to
4605                                         = skip_typeref(type->pointer.points_to);
4606                                 if (points_to->kind == TYPE_FUNCTION
4607                                     && points_to->function.modifiers & DM_NORETURN)
4608                                         return false;
4609                         }
4610
4611                         if (!expression_returns(func))
4612                                 return false;
4613
4614                         for (call_argument_t const* arg = expr->call.arguments; arg != NULL; arg = arg->next) {
4615                                 if (!expression_returns(arg->expression))
4616                                         return false;
4617                         }
4618
4619                         return true;
4620                 }
4621
4622                 case EXPR_REFERENCE:
4623                 case EXPR_ENUM_CONSTANT:
4624                 case EXPR_LITERAL_CASES:
4625                 case EXPR_LITERAL_CHARACTER:
4626                 case EXPR_STRING_LITERAL:
4627                 case EXPR_COMPOUND_LITERAL: // TODO descend into initialisers
4628                 case EXPR_LABEL_ADDRESS:
4629                 case EXPR_CLASSIFY_TYPE:
4630                 case EXPR_SIZEOF: // TODO handle obscure VLA case
4631                 case EXPR_ALIGNOF:
4632                 case EXPR_FUNCNAME:
4633                 case EXPR_BUILTIN_CONSTANT_P:
4634                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
4635                 case EXPR_OFFSETOF:
4636                 case EXPR_ERROR:
4637                         return true;
4638
4639                 case EXPR_STATEMENT: {
4640                         bool old_reaches_end = reaches_end;
4641                         reaches_end = false;
4642                         check_reachable(expr->statement.statement);
4643                         bool returns = reaches_end;
4644                         reaches_end = old_reaches_end;
4645                         return returns;
4646                 }
4647
4648                 case EXPR_CONDITIONAL:
4649                         // TODO handle constant expression
4650
4651                         if (!expression_returns(expr->conditional.condition))
4652                                 return false;
4653
4654                         if (expr->conditional.true_expression != NULL
4655                                         && expression_returns(expr->conditional.true_expression))
4656                                 return true;
4657
4658                         return expression_returns(expr->conditional.false_expression);
4659
4660                 case EXPR_SELECT:
4661                         return expression_returns(expr->select.compound);
4662
4663                 case EXPR_ARRAY_ACCESS:
4664                         return
4665                                 expression_returns(expr->array_access.array_ref) &&
4666                                 expression_returns(expr->array_access.index);
4667
4668                 case EXPR_VA_START:
4669                         return expression_returns(expr->va_starte.ap);
4670
4671                 case EXPR_VA_ARG:
4672                         return expression_returns(expr->va_arge.ap);
4673
4674                 case EXPR_VA_COPY:
4675                         return expression_returns(expr->va_copye.src);
4676
4677                 case EXPR_UNARY_CASES_MANDATORY:
4678                         return expression_returns(expr->unary.value);
4679
4680                 case EXPR_UNARY_THROW:
4681                         return false;
4682
4683                 case EXPR_BINARY_CASES:
4684                         // TODO handle constant lhs of && and ||
4685                         return
4686                                 expression_returns(expr->binary.left) &&
4687                                 expression_returns(expr->binary.right);
4688         }
4689
4690         panic("unhandled expression");
4691 }
4692
4693 static bool initializer_returns(initializer_t const *const init)
4694 {
4695         switch (init->kind) {
4696                 case INITIALIZER_VALUE:
4697                         return expression_returns(init->value.value);
4698
4699                 case INITIALIZER_LIST: {
4700                         initializer_t * const*       i       = init->list.initializers;
4701                         initializer_t * const* const end     = i + init->list.len;
4702                         bool                         returns = true;
4703                         for (; i != end; ++i) {
4704                                 if (!initializer_returns(*i))
4705                                         returns = false;
4706                         }
4707                         return returns;
4708                 }
4709
4710                 case INITIALIZER_STRING:
4711                 case INITIALIZER_DESIGNATOR: // designators have no payload
4712                         return true;
4713         }
4714         panic("unhandled initializer");
4715 }
4716
4717 static bool noreturn_candidate;
4718
4719 static void check_reachable(statement_t *const stmt)
4720 {
4721         if (stmt->base.reachable)
4722                 return;
4723         if (stmt->kind != STATEMENT_DO_WHILE)
4724                 stmt->base.reachable = true;
4725
4726         statement_t *last = stmt;
4727         statement_t *next;
4728         switch (stmt->kind) {
4729                 case STATEMENT_ERROR:
4730                 case STATEMENT_EMPTY:
4731                 case STATEMENT_ASM:
4732                         next = stmt->base.next;
4733                         break;
4734
4735                 case STATEMENT_DECLARATION: {
4736                         declaration_statement_t const *const decl = &stmt->declaration;
4737                         entity_t                const *      ent  = decl->declarations_begin;
4738                         entity_t                const *const last_decl = decl->declarations_end;
4739                         if (ent != NULL) {
4740                                 for (;; ent = ent->base.next) {
4741                                         if (ent->kind                 == ENTITY_VARIABLE &&
4742                                             ent->variable.initializer != NULL            &&
4743                                             !initializer_returns(ent->variable.initializer)) {
4744                                                 return;
4745                                         }
4746                                         if (ent == last_decl)
4747                                                 break;
4748                                 }
4749                         }
4750                         next = stmt->base.next;
4751                         break;
4752                 }
4753
4754                 case STATEMENT_COMPOUND:
4755                         next = stmt->compound.statements;
4756                         if (next == NULL)
4757                                 next = stmt->base.next;
4758                         break;
4759
4760                 case STATEMENT_RETURN: {
4761                         expression_t const *const val = stmt->returns.value;
4762                         if (val == NULL || expression_returns(val))
4763                                 noreturn_candidate = false;
4764                         return;
4765                 }
4766
4767                 case STATEMENT_IF: {
4768                         if_statement_t const *const ifs  = &stmt->ifs;
4769                         expression_t   const *const cond = ifs->condition;
4770
4771                         if (!expression_returns(cond))
4772                                 return;
4773
4774                         int const val = determine_truth(cond);
4775
4776                         if (val >= 0)
4777                                 check_reachable(ifs->true_statement);
4778
4779                         if (val > 0)
4780                                 return;
4781
4782                         if (ifs->false_statement != NULL) {
4783                                 check_reachable(ifs->false_statement);
4784                                 return;
4785                         }
4786
4787                         next = stmt->base.next;
4788                         break;
4789                 }
4790
4791                 case STATEMENT_SWITCH: {
4792                         switch_statement_t const *const switchs = &stmt->switchs;
4793                         expression_t       const *const expr    = switchs->expression;
4794
4795                         if (!expression_returns(expr))
4796                                 return;
4797
4798                         if (is_constant_expression(expr) >= EXPR_CLASS_CONSTANT) {
4799                                 ir_tarval              *const val      = fold_constant_to_tarval(expr);
4800                                 case_label_statement_t *      defaults = NULL;
4801                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4802                                         if (i->expression == NULL) {
4803                                                 defaults = i;
4804                                                 continue;
4805                                         }
4806
4807                                         if (i->first_case == val || i->last_case == val ||
4808                                                 ((tarval_cmp(i->first_case, val) & ir_relation_less_equal)
4809                                             && (tarval_cmp(val, i->last_case) & ir_relation_less_equal))) {
4810                                                 check_reachable((statement_t*)i);
4811                                                 return;
4812                                         }
4813                                 }
4814
4815                                 if (defaults != NULL) {
4816                                         check_reachable((statement_t*)defaults);
4817                                         return;
4818                                 }
4819                         } else {
4820                                 bool has_default = false;
4821                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4822                                         if (i->expression == NULL)
4823                                                 has_default = true;
4824
4825                                         check_reachable((statement_t*)i);
4826                                 }
4827
4828                                 if (has_default)
4829                                         return;
4830                         }
4831
4832                         next = stmt->base.next;
4833                         break;
4834                 }
4835
4836                 case STATEMENT_EXPRESSION: {
4837                         /* Check for noreturn function call */
4838                         expression_t const *const expr = stmt->expression.expression;
4839                         if (!expression_returns(expr))
4840                                 return;
4841
4842                         next = stmt->base.next;
4843                         break;
4844                 }
4845
4846                 case STATEMENT_CONTINUE:
4847                         for (statement_t *parent = stmt;;) {
4848                                 parent = parent->base.parent;
4849                                 if (parent == NULL) /* continue not within loop */
4850                                         return;
4851
4852                                 next = parent;
4853                                 switch (parent->kind) {
4854                                         case STATEMENT_DO_WHILE: goto continue_do_while;
4855                                         case STATEMENT_FOR:      goto continue_for;
4856
4857                                         default: break;
4858                                 }
4859                         }
4860
4861                 case STATEMENT_BREAK:
4862                         for (statement_t *parent = stmt;;) {
4863                                 parent = parent->base.parent;
4864                                 if (parent == NULL) /* break not within loop/switch */
4865                                         return;
4866
4867                                 switch (parent->kind) {
4868                                         case STATEMENT_SWITCH:
4869                                         case STATEMENT_DO_WHILE:
4870                                         case STATEMENT_FOR:
4871                                                 last = parent;
4872                                                 next = parent->base.next;
4873                                                 goto found_break_parent;
4874
4875                                         default: break;
4876                                 }
4877                         }
4878 found_break_parent:
4879                         break;
4880
4881                 case STATEMENT_COMPUTED_GOTO: {
4882                         if (!expression_returns(stmt->computed_goto.expression))
4883                                 return;
4884
4885                         statement_t *parent = stmt->base.parent;
4886                         if (parent == NULL) /* top level goto */
4887                                 return;
4888                         next = parent;
4889                         break;
4890                 }
4891
4892                 case STATEMENT_GOTO:
4893                         next = stmt->gotos.label->statement;
4894                         if (next == NULL) /* missing label */
4895                                 return;
4896                         break;
4897
4898                 case STATEMENT_LABEL:
4899                         next = stmt->label.statement;
4900                         break;
4901
4902                 case STATEMENT_CASE_LABEL:
4903                         next = stmt->case_label.statement;
4904                         break;
4905
4906                 case STATEMENT_DO_WHILE:
4907                         next = stmt->do_while.body;
4908                         break;
4909
4910                 case STATEMENT_FOR: {
4911                         for_statement_t *const fors = &stmt->fors;
4912
4913                         if (fors->condition_reachable)
4914                                 return;
4915                         fors->condition_reachable = true;
4916
4917                         expression_t const *const cond = fors->condition;
4918
4919                         int val;
4920                         if (cond == NULL) {
4921                                 val = 1;
4922                         } else if (expression_returns(cond)) {
4923                                 val = determine_truth(cond);
4924                         } else {
4925                                 return;
4926                         }
4927
4928                         if (val >= 0)
4929                                 check_reachable(fors->body);
4930
4931                         if (val > 0)
4932                                 return;
4933
4934                         next = stmt->base.next;
4935                         break;
4936                 }
4937
4938                 case STATEMENT_MS_TRY: {
4939                         ms_try_statement_t const *const ms_try = &stmt->ms_try;
4940                         check_reachable(ms_try->try_statement);
4941                         next = ms_try->final_statement;
4942                         break;
4943                 }
4944
4945                 case STATEMENT_LEAVE: {
4946                         statement_t *parent = stmt;
4947                         for (;;) {
4948                                 parent = parent->base.parent;
4949                                 if (parent == NULL) /* __leave not within __try */
4950                                         return;
4951
4952                                 if (parent->kind == STATEMENT_MS_TRY) {
4953                                         last = parent;
4954                                         next = parent->ms_try.final_statement;
4955                                         break;
4956                                 }
4957                         }
4958                         break;
4959                 }
4960
4961                 default:
4962                         panic("invalid statement kind");
4963         }
4964
4965         while (next == NULL) {
4966                 next = last->base.parent;
4967                 if (next == NULL) {
4968                         noreturn_candidate = false;
4969
4970                         type_t *const type = skip_typeref(current_function->base.type);
4971                         assert(is_type_function(type));
4972                         type_t *const ret  = skip_typeref(type->function.return_type);
4973                         if (!is_type_void(ret) &&
4974                             is_type_valid(ret) &&
4975                             !is_main(current_entity)) {
4976                                 position_t const *const pos = &stmt->base.pos;
4977                                 warningf(WARN_RETURN_TYPE, pos, "control reaches end of non-void function");
4978                         }
4979                         return;
4980                 }
4981
4982                 switch (next->kind) {
4983                         case STATEMENT_ERROR:
4984                         case STATEMENT_EMPTY:
4985                         case STATEMENT_DECLARATION:
4986                         case STATEMENT_EXPRESSION:
4987                         case STATEMENT_ASM:
4988                         case STATEMENT_RETURN:
4989                         case STATEMENT_CONTINUE:
4990                         case STATEMENT_BREAK:
4991                         case STATEMENT_COMPUTED_GOTO:
4992                         case STATEMENT_GOTO:
4993                         case STATEMENT_LEAVE:
4994                                 panic("invalid control flow in function");
4995
4996                         case STATEMENT_COMPOUND:
4997                                 if (next->compound.stmt_expr) {
4998                                         reaches_end = true;
4999                                         return;
5000                                 }
5001                                 /* FALLTHROUGH */
5002                         case STATEMENT_IF:
5003                         case STATEMENT_SWITCH:
5004                         case STATEMENT_LABEL:
5005                         case STATEMENT_CASE_LABEL:
5006                                 last = next;
5007                                 next = next->base.next;
5008                                 break;
5009
5010                         case STATEMENT_DO_WHILE: {
5011 continue_do_while:
5012                                 if (next->base.reachable)
5013                                         return;
5014                                 next->base.reachable = true;
5015
5016                                 do_while_statement_t const *const dw   = &next->do_while;
5017                                 expression_t         const *const cond = dw->condition;
5018
5019                                 if (!expression_returns(cond))
5020                                         return;
5021
5022                                 int const val = determine_truth(cond);
5023
5024                                 if (val >= 0)
5025                                         check_reachable(dw->body);
5026
5027                                 if (val > 0)
5028                                         return;
5029
5030                                 last = next;
5031                                 next = next->base.next;
5032                                 break;
5033                         }
5034
5035                         case STATEMENT_FOR: {
5036 continue_for:;
5037                                 for_statement_t *const fors = &next->fors;
5038
5039                                 fors->step_reachable = true;
5040
5041                                 if (fors->condition_reachable)
5042                                         return;
5043                                 fors->condition_reachable = true;
5044
5045                                 expression_t const *const cond = fors->condition;
5046
5047                                 int val;
5048                                 if (cond == NULL) {
5049                                         val = 1;
5050                                 } else if (expression_returns(cond)) {
5051                                         val = determine_truth(cond);
5052                                 } else {
5053                                         return;
5054                                 }
5055
5056                                 if (val >= 0)
5057                                         check_reachable(fors->body);
5058
5059                                 if (val > 0)
5060                                         return;
5061
5062                                 last = next;
5063                                 next = next->base.next;
5064                                 break;
5065                         }
5066
5067                         case STATEMENT_MS_TRY:
5068                                 last = next;
5069                                 next = next->ms_try.final_statement;
5070                                 break;
5071                 }
5072         }
5073
5074         check_reachable(next);
5075 }
5076
5077 static void check_unreachable(statement_t* const stmt, void *const env)
5078 {
5079         (void)env;
5080
5081         switch (stmt->kind) {
5082                 case STATEMENT_DO_WHILE:
5083                         if (!stmt->base.reachable) {
5084                                 expression_t const *const cond = stmt->do_while.condition;
5085                                 if (determine_truth(cond) >= 0) {
5086                                         position_t const *const pos = &cond->base.pos;
5087                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of do-while-loop is unreachable");
5088                                 }
5089                         }
5090                         return;
5091
5092                 case STATEMENT_FOR: {
5093                         for_statement_t const* const fors = &stmt->fors;
5094
5095                         // if init and step are unreachable, cond is unreachable, too
5096                         if (!stmt->base.reachable && !fors->step_reachable) {
5097                                 goto warn_unreachable;
5098                         } else {
5099                                 if (!stmt->base.reachable && fors->initialisation != NULL) {
5100                                         position_t const *const pos = &fors->initialisation->base.pos;
5101                                         warningf(WARN_UNREACHABLE_CODE, pos, "initialisation of for-statement is unreachable");
5102                                 }
5103
5104                                 if (!fors->condition_reachable && fors->condition != NULL) {
5105                                         position_t const *const pos = &fors->condition->base.pos;
5106                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of for-statement is unreachable");
5107                                 }
5108
5109                                 if (!fors->step_reachable && fors->step != NULL) {
5110                                         position_t const *const pos = &fors->step->base.pos;
5111                                         warningf(WARN_UNREACHABLE_CODE, pos, "step of for-statement is unreachable");
5112                                 }
5113                         }
5114                         return;
5115                 }
5116
5117                 case STATEMENT_COMPOUND:
5118                         if (stmt->compound.statements != NULL)
5119                                 return;
5120                         goto warn_unreachable;
5121
5122                 case STATEMENT_DECLARATION: {
5123                         /* Only warn if there is at least one declarator with an initializer.
5124                          * This typically occurs in switch statements. */
5125                         declaration_statement_t const *const decl = &stmt->declaration;
5126                         entity_t                const *      ent  = decl->declarations_begin;
5127                         entity_t                const *const last = decl->declarations_end;
5128                         if (ent != NULL) {
5129                                 for (;; ent = ent->base.next) {
5130                                         if (ent->kind                 == ENTITY_VARIABLE &&
5131                                                         ent->variable.initializer != NULL) {
5132                                                 goto warn_unreachable;
5133                                         }
5134                                         if (ent == last)
5135                                                 return;
5136                                 }
5137                         }
5138                 }
5139
5140                 default:
5141 warn_unreachable:
5142                         if (!stmt->base.reachable) {
5143                                 position_t const *const pos = &stmt->base.pos;
5144                                 warningf(WARN_UNREACHABLE_CODE, pos, "statement is unreachable");
5145                         }
5146                         return;
5147         }
5148 }
5149
5150 static bool is_main(entity_t *entity)
5151 {
5152         static symbol_t *sym_main = NULL;
5153         if (sym_main == NULL) {
5154                 sym_main = symbol_table_insert("main");
5155         }
5156
5157         if (entity->base.symbol != sym_main)
5158                 return false;
5159         /* must be in outermost scope */
5160         if (entity->base.parent_scope != file_scope)
5161                 return false;
5162
5163         return true;
5164 }
5165
5166 static void prepare_main_collect2(entity_t*);
5167
5168 static void parse_external_declaration(void)
5169 {
5170         /* function-definitions and declarations both start with declaration
5171          * specifiers */
5172         add_anchor_token(';');
5173         declaration_specifiers_t specifiers;
5174         parse_declaration_specifiers(&specifiers);
5175         rem_anchor_token(';');
5176
5177         /* must be a declaration */
5178         if (token.kind == ';') {
5179                 parse_anonymous_declaration_rest(&specifiers);
5180                 return;
5181         }
5182
5183         add_anchor_token(',');
5184         add_anchor_token('=');
5185         add_anchor_token(';');
5186         add_anchor_token('{');
5187
5188         /* declarator is common to both function-definitions and declarations */
5189         entity_t *ndeclaration = parse_declarator(&specifiers, DECL_FLAGS_NONE);
5190
5191         rem_anchor_token('{');
5192         rem_anchor_token(';');
5193         rem_anchor_token('=');
5194         rem_anchor_token(',');
5195
5196         /* must be a declaration */
5197         switch (token.kind) {
5198                 case ',':
5199                 case ';':
5200                 case '=':
5201                         parse_declaration_rest(ndeclaration, &specifiers, record_entity,
5202                                         DECL_FLAGS_NONE);
5203                         return;
5204         }
5205
5206         /* must be a function definition */
5207         parse_kr_declaration_list(ndeclaration);
5208
5209         if (token.kind != '{') {
5210                 parse_error_expected("while parsing function definition", '{', NULL);
5211                 eat_until_matching_token(';');
5212                 return;
5213         }
5214
5215         {
5216                 assert(is_declaration(ndeclaration));
5217                 type_t *const orig_type = ndeclaration->declaration.type;
5218                 type_t *const type      = skip_typeref(orig_type);
5219
5220                 if (!is_type_function(type)) {
5221                         if (is_type_valid(type)) {
5222                                 errorf(HERE, "declarator '%#N' has a body but is not a function type", ndeclaration);
5223                         }
5224                         eat_block();
5225                         return;
5226                 }
5227
5228                 position_t const *const pos = &ndeclaration->base.pos;
5229                 if (is_typeref(orig_type)) {
5230                         /* §6.9.1:2 */
5231                         errorf(pos, "type of function definition '%#N' is a typedef", ndeclaration);
5232                 }
5233
5234                 if (is_type_compound(skip_typeref(type->function.return_type))) {
5235                         warningf(WARN_AGGREGATE_RETURN, pos, "'%N' returns an aggregate", ndeclaration);
5236                 }
5237                 if (type->function.unspecified_parameters) {
5238                         warningf(WARN_OLD_STYLE_DEFINITION, pos, "old-style definition of '%N'", ndeclaration);
5239                 } else {
5240                         warningf(WARN_TRADITIONAL, pos, "traditional C rejects ISO C style definition of '%N'", ndeclaration);
5241                 }
5242
5243                 /* §6.7.5.3:14 a function definition with () means no
5244                  * parameters (and not unspecified parameters) */
5245                 if (type->function.unspecified_parameters &&
5246                                 type->function.parameters == NULL) {
5247                         type_t *copy                          = duplicate_type(type);
5248                         copy->function.unspecified_parameters = false;
5249                         ndeclaration->declaration.type = identify_new_type(copy);
5250                 }
5251         }
5252
5253         entity_t *const entity = record_entity(ndeclaration, true);
5254         assert(entity->kind == ENTITY_FUNCTION);
5255         assert(ndeclaration->kind == ENTITY_FUNCTION);
5256
5257         function_t *const function = &entity->function;
5258         if (ndeclaration != entity) {
5259                 function->parameters = ndeclaration->function.parameters;
5260         }
5261
5262         PUSH_SCOPE(&function->parameters);
5263
5264         entity_t *parameter = function->parameters.entities;
5265         for (; parameter != NULL; parameter = parameter->base.next) {
5266                 if (parameter->base.parent_scope == &ndeclaration->function.parameters) {
5267                         parameter->base.parent_scope = current_scope;
5268                 }
5269                 assert(parameter->base.parent_scope == NULL
5270                                 || parameter->base.parent_scope == current_scope);
5271                 parameter->base.parent_scope = current_scope;
5272                 if (parameter->base.symbol == NULL) {
5273                         errorf(&parameter->base.pos, "parameter name omitted");
5274                         continue;
5275                 }
5276                 environment_push(parameter);
5277         }
5278
5279         if (function->body != NULL) {
5280                 parser_error_multiple_definition(entity, HERE);
5281                 eat_block();
5282         } else {
5283                 /* parse function body */
5284                 int         label_stack_top      = label_top();
5285                 function_t *old_current_function = current_function;
5286                 current_function                 = function;
5287                 PUSH_CURRENT_ENTITY(entity);
5288                 PUSH_PARENT(NULL);
5289
5290                 goto_first   = NULL;
5291                 goto_anchor  = &goto_first;
5292                 label_first  = NULL;
5293                 label_anchor = &label_first;
5294
5295                 statement_t *const body = parse_compound_statement(false);
5296                 function->body = body;
5297                 first_err = true;
5298                 check_labels();
5299                 check_declarations();
5300                 if (is_warn_on(WARN_RETURN_TYPE)      ||
5301                     is_warn_on(WARN_UNREACHABLE_CODE) ||
5302                     (is_warn_on(WARN_MISSING_NORETURN) && !(function->base.modifiers & DM_NORETURN))) {
5303                         noreturn_candidate = true;
5304                         check_reachable(body);
5305                         if (is_warn_on(WARN_UNREACHABLE_CODE))
5306                                 walk_statements(body, check_unreachable, NULL);
5307                         if (noreturn_candidate &&
5308                             !(function->base.modifiers & DM_NORETURN)) {
5309                                 warningf(WARN_MISSING_NORETURN, &body->base.pos, "function '%#N' is candidate for attribute 'noreturn'", entity);
5310                         }
5311                 }
5312
5313                 if (is_main(entity)) {
5314                         /* Force main to C linkage. */
5315                         type_t *const type = entity->declaration.type;
5316                         assert(is_type_function(type));
5317                         if (type->function.linkage != LINKAGE_C) {
5318                                 type_t *new_type           = duplicate_type(type);
5319                                 new_type->function.linkage = LINKAGE_C;
5320                                 entity->declaration.type   = identify_new_type(new_type);
5321                         }
5322
5323                         if (enable_main_collect2_hack)
5324                                 prepare_main_collect2(entity);
5325                 }
5326
5327                 POP_CURRENT_ENTITY();
5328                 POP_PARENT();
5329                 assert(current_function == function);
5330                 current_function = old_current_function;
5331                 label_pop_to(label_stack_top);
5332         }
5333
5334         POP_SCOPE();
5335 }
5336
5337 static entity_t *find_compound_entry(compound_t *compound, symbol_t *symbol)
5338 {
5339         entity_t *iter = compound->members.entities;
5340         for (; iter != NULL; iter = iter->base.next) {
5341                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5342                         continue;
5343
5344                 if (iter->base.symbol == symbol) {
5345                         return iter;
5346                 } else if (iter->base.symbol == NULL) {
5347                         /* search in anonymous structs and unions */
5348                         type_t *type = skip_typeref(iter->declaration.type);
5349                         if (is_type_compound(type)) {
5350                                 if (find_compound_entry(type->compound.compound, symbol)
5351                                                 != NULL)
5352                                         return iter;
5353                         }
5354                         continue;
5355                 }
5356         }
5357
5358         return NULL;
5359 }
5360
5361 static void check_deprecated(const position_t *pos, const entity_t *entity)
5362 {
5363         if (!is_declaration(entity))
5364                 return;
5365         if ((entity->declaration.modifiers & DM_DEPRECATED) == 0)
5366                 return;
5367
5368         position_t const *const epos = &entity->base.pos;
5369         char       const *const msg  = get_deprecated_string(entity->declaration.attributes);
5370         if (msg != NULL) {
5371                 warningf(WARN_DEPRECATED_DECLARATIONS, pos, "'%N' is deprecated (declared %P): \"%s\"", entity, epos, msg);
5372         } else {
5373                 warningf(WARN_DEPRECATED_DECLARATIONS, pos, "'%N' is deprecated (declared %P)", entity, epos);
5374         }
5375 }
5376
5377
5378 static expression_t *create_select(const position_t *pos, expression_t *addr,
5379                                    type_qualifiers_t qualifiers,
5380                                                                    entity_t *entry)
5381 {
5382         assert(entry->kind == ENTITY_COMPOUND_MEMBER);
5383
5384         check_deprecated(pos, entry);
5385
5386         expression_t *select          = allocate_expression_zero(EXPR_SELECT);
5387         select->base.pos              = *pos;
5388         select->select.compound       = addr;
5389         select->select.compound_entry = entry;
5390
5391         type_t *entry_type = entry->declaration.type;
5392         type_t *res_type   = get_qualified_type(entry_type, qualifiers);
5393
5394         /* bitfields need special treatment */
5395         if (entry->compound_member.bitfield) {
5396                 unsigned bit_size = entry->compound_member.bit_size;
5397                 /* if fewer bits than an int, convert to int (see §6.3.1.1) */
5398                 if (bit_size < get_atomic_type_size(ATOMIC_TYPE_INT) * BITS_PER_BYTE) {
5399                         res_type = type_int;
5400                 }
5401         }
5402
5403         /* we always do the auto-type conversions; the & and sizeof parser contains
5404          * code to revert this! */
5405         select->base.type = automatic_type_conversion(res_type);
5406
5407
5408         return select;
5409 }
5410
5411 /**
5412  * Find entry with symbol in compound. Search anonymous structs and unions and
5413  * creates implicit select expressions for them.
5414  * Returns the adress for the innermost compound.
5415  */
5416 static expression_t *find_create_select(const position_t *pos,
5417                                         expression_t *addr,
5418                                         type_qualifiers_t qualifiers,
5419                                         compound_t *compound, symbol_t *symbol)
5420 {
5421         entity_t *iter = compound->members.entities;
5422         for (; iter != NULL; iter = iter->base.next) {
5423                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5424                         continue;
5425
5426                 symbol_t *iter_symbol = iter->base.symbol;
5427                 if (iter_symbol == NULL) {
5428                         type_t *type = iter->declaration.type;
5429                         if (!is_type_compound(type))
5430                                 continue;
5431
5432                         compound_t *sub_compound = type->compound.compound;
5433
5434                         if (find_compound_entry(sub_compound, symbol) == NULL)
5435                                 continue;
5436
5437                         expression_t *sub_addr = create_select(pos, addr, qualifiers, iter);
5438                         sub_addr->base.implicit = true;
5439                         return find_create_select(pos, sub_addr, qualifiers, sub_compound,
5440                                                   symbol);
5441                 }
5442
5443                 if (iter_symbol == symbol) {
5444                         return create_select(pos, addr, qualifiers, iter);
5445                 }
5446         }
5447
5448         return NULL;
5449 }
5450
5451 static void parse_bitfield_member(entity_t *entity)
5452 {
5453         eat(':');
5454
5455         expression_t *size = parse_constant_expression();
5456         long          size_long;
5457
5458         assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5459         type_t *type = entity->declaration.type;
5460         if (!is_type_integer(skip_typeref(type))) {
5461                 errorf(HERE, "bitfield base type '%T' is not an integer type",
5462                            type);
5463         }
5464
5465         if (is_constant_expression(size) < EXPR_CLASS_CONSTANT) {
5466                 /* error already reported by parse_constant_expression */
5467                 size_long = get_type_size(type) * 8;
5468         } else {
5469                 size_long = fold_constant_to_int(size);
5470
5471                 const symbol_t *symbol = entity->base.symbol;
5472                 const symbol_t *user_symbol
5473                         = symbol == NULL ? sym_anonymous : symbol;
5474                 unsigned bit_size = get_type_size(type) * 8;
5475                 if (size_long < 0) {
5476                         errorf(HERE, "negative width in bit-field '%Y'", user_symbol);
5477                 } else if (size_long == 0 && symbol != NULL) {
5478                         errorf(HERE, "zero width for bit-field '%Y'", user_symbol);
5479                 } else if (bit_size > 0 && (unsigned)size_long > bit_size) {
5480                         errorf(HERE, "width of bitfield '%Y' exceeds its type",
5481                                    user_symbol);
5482                 } else {
5483                         /* hope that people don't invent crazy types with more bits
5484                          * than our struct can hold */
5485                         assert(size_long <
5486                                    (1 << sizeof(entity->compound_member.bit_size)*8));
5487                 }
5488         }
5489
5490         entity->compound_member.bitfield = true;
5491         entity->compound_member.bit_size = (unsigned char)size_long;
5492 }
5493
5494 static void parse_compound_declarators(compound_t *compound,
5495                 const declaration_specifiers_t *specifiers)
5496 {
5497         add_anchor_token(';');
5498         add_anchor_token(',');
5499         do {
5500                 entity_t         *const entity = parse_declarator(specifiers, DECL_MAY_BE_ABSTRACT | DECL_CREATE_COMPOUND_MEMBER);
5501                 position_t const *const pos    = &entity->base.pos;
5502                 if (entity->kind == ENTITY_TYPEDEF) {
5503                         errorf(pos, "typedef not allowed as compound member");
5504                         continue;
5505                 }
5506
5507                 assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5508
5509                 /* make sure we don't define a symbol multiple times */
5510                 symbol_t *symbol = entity->base.symbol;
5511                 if (symbol != NULL) {
5512                         entity_t *prev = find_compound_entry(compound, symbol);
5513                         if (prev != NULL) {
5514                                 position_t const *const ppos = &prev->base.pos;
5515                                 errorf(pos, "multiple declarations of '%N' (declared %P)", entity, ppos);
5516                         }
5517                 }
5518
5519                 if (token.kind == ':') {
5520                         parse_bitfield_member(entity);
5521
5522                         attribute_t *attributes = parse_attributes(NULL);
5523                         handle_entity_attributes(attributes, entity);
5524                 } else {
5525                         type_t *orig_type = entity->declaration.type;
5526                         type_t *type      = skip_typeref(orig_type);
5527                         if (is_type_function(type)) {
5528                                 errorf(pos, "'%N' must not have function type '%T'", entity, orig_type);
5529                         } else if (is_type_incomplete(type)) {
5530                                 /* §6.7.2.1:16 flexible array member */
5531                                 if (!is_type_array(type)       ||
5532                                                 token.kind          != ';' ||
5533                                                 look_ahead(1)->kind != '}') {
5534                                         errorf(pos, "'%N' has incomplete type '%T'", entity, orig_type);
5535                                 } else if (compound->members.entities == NULL) {
5536                                         errorf(pos, "flexible array member in otherwise empty struct");
5537                                 }
5538                         }
5539                 }
5540
5541                 append_entity(&compound->members, entity);
5542         } while (accept(','));
5543         rem_anchor_token(',');
5544         rem_anchor_token(';');
5545         expect(';');
5546
5547         anonymous_entity = NULL;
5548 }
5549
5550 static void parse_compound_type_entries(compound_t *compound)
5551 {
5552         eat('{');
5553         add_anchor_token('}');
5554
5555         for (;;) {
5556                 switch (token.kind) {
5557                         DECLARATION_START
5558                         case T___extension__:
5559                         case T_IDENTIFIER: {
5560                                 PUSH_EXTENSION();
5561                                 declaration_specifiers_t specifiers;
5562                                 parse_declaration_specifiers(&specifiers);
5563                                 parse_compound_declarators(compound, &specifiers);
5564                                 POP_EXTENSION();
5565                                 break;
5566                         }
5567
5568                         default:
5569                                 rem_anchor_token('}');
5570                                 expect('}');
5571                                 /* §6.7.2.1:7 */
5572                                 compound->complete = true;
5573                                 return;
5574                 }
5575         }
5576 }
5577
5578 static type_t *parse_typename(void)
5579 {
5580         declaration_specifiers_t specifiers;
5581         parse_declaration_specifiers(&specifiers);
5582         if (specifiers.storage_class != STORAGE_CLASS_NONE
5583                         || specifiers.thread_local) {
5584                 /* TODO: improve error message, user does probably not know what a
5585                  * storage class is...
5586                  */
5587                 errorf(&specifiers.pos, "typename must not have a storage class");
5588         }
5589
5590         type_t *result = parse_abstract_declarator(specifiers.type);
5591
5592         return result;
5593 }
5594
5595
5596
5597
5598 typedef expression_t* (*parse_expression_function)(void);
5599 typedef expression_t* (*parse_expression_infix_function)(expression_t *left);
5600
5601 typedef struct expression_parser_function_t expression_parser_function_t;
5602 struct expression_parser_function_t {
5603         parse_expression_function        parser;
5604         precedence_t                     infix_precedence;
5605         parse_expression_infix_function  infix_parser;
5606 };
5607
5608 static expression_parser_function_t expression_parsers[T_LAST_TOKEN];
5609
5610 static type_t *get_string_type(string_encoding_t const enc)
5611 {
5612         bool const warn = is_warn_on(WARN_WRITE_STRINGS);
5613         switch (enc) {
5614         case STRING_ENCODING_CHAR:
5615         case STRING_ENCODING_UTF8:   return warn ? type_const_char_ptr     : type_char_ptr;
5616         case STRING_ENCODING_CHAR16: return warn ? type_char16_t_const_ptr : type_char16_t_ptr;
5617         case STRING_ENCODING_CHAR32: return warn ? type_char32_t_const_ptr : type_char32_t_ptr;
5618         case STRING_ENCODING_WIDE:   return warn ? type_const_wchar_t_ptr  : type_wchar_t_ptr;
5619         }
5620         panic("invalid string encoding");
5621 }
5622
5623 /**
5624  * Parse a string constant.
5625  */
5626 static expression_t *parse_string_literal(void)
5627 {
5628         expression_t *const expr = allocate_expression_zero(EXPR_STRING_LITERAL);
5629         expr->string_literal.value = concat_string_literals();
5630         expr->base.type            = get_string_type(expr->string_literal.value.encoding);
5631         return expr;
5632 }
5633
5634 /**
5635  * Parse a boolean constant.
5636  */
5637 static expression_t *parse_boolean_literal(bool value)
5638 {
5639         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_BOOLEAN);
5640         literal->base.type           = type_bool;
5641         literal->literal.value.begin = value ? "true" : "false";
5642         literal->literal.value.size  = value ? 4 : 5;
5643
5644         eat(value ? T_true : T_false);
5645         return literal;
5646 }
5647
5648 static void check_number_suffix(expression_t *const expr, char const *const suffix, bool const is_float)
5649 {
5650         unsigned spec = SPECIFIER_NONE;
5651         for (char const *c = suffix; *c != '\0'; ++c) {
5652                 specifiers_t add;
5653                 switch (*c) {
5654                 case 'F': case 'f':
5655                         add = SPECIFIER_FLOAT;
5656                         break;
5657
5658                 case 'L': case 'l':
5659                         add = SPECIFIER_LONG;
5660                         if (*c == c[1] && !is_float) {
5661                                 add |= SPECIFIER_LONG_LONG;
5662                                 ++c;
5663                         }
5664                         break;
5665
5666                 case 'U': case 'u':
5667                         add = SPECIFIER_UNSIGNED;
5668                         break;
5669
5670                 case 'I': case 'i':
5671                 case 'J': case 'j':
5672                         add = SPECIFIER_COMPLEX;
5673                         break;
5674
5675                 default:
5676                         goto error;
5677                 }
5678                 if (spec & add)
5679                         goto error;
5680                 spec |= add;
5681         }
5682
5683         if (!(spec & SPECIFIER_FLOAT) && is_float)
5684                 spec |= SPECIFIER_DOUBLE;
5685
5686         if (!(spec & (SPECIFIER_FLOAT | SPECIFIER_DOUBLE)) == is_float)
5687                 goto error;
5688
5689         type_t *type;
5690         switch (spec & ~SPECIFIER_COMPLEX) {
5691         case SPECIFIER_NONE:                                            type = type_int;                break;
5692         case                      SPECIFIER_LONG:                       type = type_long;               break;
5693         case                      SPECIFIER_LONG | SPECIFIER_LONG_LONG: type = type_long_long;          break;
5694         case SPECIFIER_UNSIGNED:                                        type = type_unsigned_int;       break;
5695         case SPECIFIER_UNSIGNED | SPECIFIER_LONG:                       type = type_unsigned_long;      break;
5696         case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG: type = type_unsigned_long_long; break;
5697         case SPECIFIER_FLOAT:                                           type = type_float;              break;
5698         case SPECIFIER_DOUBLE:                                          type = type_double;             break;
5699         case SPECIFIER_DOUBLE   | SPECIFIER_LONG:                       type = type_long_double;        break;
5700
5701         default:
5702 error:
5703                 errorf(HERE, "invalid suffix '%s' on %s constant", suffix, is_float ? "floatingpoint" : "integer");
5704                 return;
5705         }
5706
5707         if (spec != SPECIFIER_NONE && spec != SPECIFIER_LONG && spec != SPECIFIER_DOUBLE)
5708                 warningf(WARN_TRADITIONAL, HERE, "traditional C rejects the '%s' suffix", suffix);
5709
5710         if (spec & SPECIFIER_COMPLEX)
5711                 type = make_complex_type(get_arithmetic_akind(type), TYPE_QUALIFIER_NONE);
5712
5713         expr->base.type = type;
5714         if (!is_float) {
5715                 /* Integer type depends on the size of the number and the size
5716                  * representable by the types. The backend/codegeneration has to
5717                  * determine that. */
5718                 determine_literal_type(&expr->literal);
5719         }
5720 }
5721
5722 static expression_t *parse_number_literal(void)
5723 {
5724         string_t const *const str      = &token.literal.string;
5725         char     const *      i        = str->begin;
5726         unsigned              digits   = 0;
5727         bool                  is_float = false;
5728
5729         /* Parse base prefix. */
5730         unsigned base;
5731         if (*i == '0') {
5732                 switch (*++i) {
5733                 case 'B': case 'b': base =  2; ++i;               break;
5734                 case 'X': case 'x': base = 16; ++i;               break;
5735                 default:            base =  8; digits |= 1U << 0; break;
5736                 }
5737         } else {
5738                 base = 10;
5739         }
5740
5741         /* Parse mantissa. */
5742         for (;; ++i) {
5743                 unsigned digit;
5744                 switch (*i) {
5745                 case '.':
5746                         if (is_float) {
5747                                 errorf(HERE, "multiple decimal points in %K", &token);
5748                                 i = 0;
5749                                 goto done;
5750                         }
5751                         is_float = true;
5752                         if (base == 8)
5753                                 base = 10;
5754                         continue;
5755
5756                 case '0':           digit =  0; break;
5757                 case '1':           digit =  1; break;
5758                 case '2':           digit =  2; break;
5759                 case '3':           digit =  3; break;
5760                 case '4':           digit =  4; break;
5761                 case '5':           digit =  5; break;
5762                 case '6':           digit =  6; break;
5763                 case '7':           digit =  7; break;
5764                 case '8':           digit =  8; break;
5765                 case '9':           digit =  9; break;
5766                 case 'A': case 'a': digit = 10; break;
5767                 case 'B': case 'b': digit = 11; break;
5768                 case 'C': case 'c': digit = 12; break;
5769                 case 'D': case 'd': digit = 13; break;
5770                 case 'E': case 'e': digit = 14; break;
5771                 case 'F': case 'f': digit = 15; break;
5772
5773                 default: goto done_mantissa;
5774                 }
5775
5776                 if (digit >= 10 && base != 16)
5777                         goto done_mantissa;
5778
5779                 digits |= 1U << digit;
5780         }
5781 done_mantissa:
5782
5783         /* Parse exponent. */
5784         switch (base) {
5785         case 2:
5786                 if (is_float)
5787                         errorf(HERE, "binary floating %K not allowed", &token);
5788                 break;
5789
5790         case  8:
5791         case 10:
5792                 if (*i == 'E' || *i == 'e') {
5793                         base = 10;
5794                         goto parse_exponent;
5795                 }
5796                 break;
5797
5798         case 16:
5799                 if (*i == 'P' || *i == 'p') {
5800 parse_exponent:
5801                         ++i;
5802                         is_float = true;
5803
5804                         if (*i == '-' || *i == '+')
5805                                 ++i;
5806
5807                         if (isdigit(*i)) {
5808                                 do {
5809                                         ++i;
5810                                 } while (isdigit(*i));
5811                         } else {
5812                                 errorf(HERE, "exponent of %K has no digits", &token);
5813                         }
5814                 } else if (is_float) {
5815                         errorf(HERE, "hexadecimal floating %K requires an exponent", &token);
5816                         i = 0;
5817                 }
5818                 break;
5819
5820         default:
5821                 panic("invalid base");
5822         }
5823
5824 done:;
5825         expression_t *const expr = allocate_expression_zero(is_float ? EXPR_LITERAL_FLOATINGPOINT : EXPR_LITERAL_INTEGER);
5826         expr->literal.value = *str;
5827
5828         if (i) {
5829                 if (digits == 0) {
5830                         errorf(HERE, "%K has no digits", &token);
5831                 } else if (digits & ~((1U << base) - 1)) {
5832                         errorf(HERE, "invalid digit in %K", &token);
5833                 } else {
5834                         expr->literal.suffix = i;
5835                         check_number_suffix(expr, i, is_float);
5836                 }
5837         }
5838
5839         eat(T_NUMBER);
5840         return expr;
5841 }
5842
5843 /**
5844  * Parse a character constant.
5845  */
5846 static expression_t *parse_character_constant(void)
5847 {
5848         expression_t *const literal = allocate_expression_zero(EXPR_LITERAL_CHARACTER);
5849         literal->string_literal.value = token.literal.string;
5850
5851         size_t const size = get_string_len(&token.literal.string);
5852         switch (token.literal.string.encoding) {
5853         case STRING_ENCODING_CHAR:
5854         case STRING_ENCODING_UTF8:
5855                 literal->base.type = c_mode & _CXX ? type_char : type_int;
5856                 if (size > 1) {
5857                         if (!GNU_MODE && !(c_mode & _C99)) {
5858                                 errorf(HERE, "more than 1 character in character constant");
5859                         } else {
5860                                 literal->base.type = type_int;
5861                                 warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5862                         }
5863                 }
5864                 break;
5865
5866         case STRING_ENCODING_CHAR16: literal->base.type = type_char16_t; goto warn_multi;
5867         case STRING_ENCODING_CHAR32: literal->base.type = type_char32_t; goto warn_multi;
5868         case STRING_ENCODING_WIDE:   literal->base.type = type_wchar_t;  goto warn_multi;
5869 warn_multi:
5870                 if (size > 1) {
5871                         warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5872                 }
5873                 break;
5874         }
5875
5876         eat(T_CHARACTER_CONSTANT);
5877         return literal;
5878 }
5879
5880 static entity_t *create_implicit_function(symbol_t *symbol, position_t const *const pos)
5881 {
5882         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
5883         ntype->function.return_type            = type_int;
5884         ntype->function.unspecified_parameters = true;
5885         ntype->function.linkage                = LINKAGE_C;
5886         type_t *type                           = identify_new_type(ntype);
5887
5888         entity_t *const entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, symbol, pos);
5889         entity->declaration.storage_class          = STORAGE_CLASS_EXTERN;
5890         entity->declaration.declared_storage_class = STORAGE_CLASS_EXTERN;
5891         entity->declaration.type                   = type;
5892         entity->declaration.implicit               = true;
5893
5894         if (current_scope != NULL)
5895                 record_entity(entity, false);
5896
5897         return entity;
5898 }
5899
5900 /**
5901  * Performs automatic type cast as described in §6.3.2.1.
5902  *
5903  * @param orig_type  the original type
5904  */
5905 static type_t *automatic_type_conversion(type_t *orig_type)
5906 {
5907         type_t *type = skip_typeref(orig_type);
5908         if (is_type_array(type)) {
5909                 array_type_t *array_type   = &type->array;
5910                 type_t       *element_type = array_type->element_type;
5911                 unsigned      qualifiers   = array_type->base.qualifiers;
5912
5913                 return make_pointer_type(element_type, qualifiers);
5914         }
5915
5916         if (is_type_function(type)) {
5917                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
5918         }
5919
5920         return orig_type;
5921 }
5922
5923 /**
5924  * reverts the automatic casts of array to pointer types and function
5925  * to function-pointer types as defined §6.3.2.1
5926  */
5927 type_t *revert_automatic_type_conversion(const expression_t *expression)
5928 {
5929         switch (expression->kind) {
5930         case EXPR_REFERENCE: {
5931                 entity_t *entity = expression->reference.entity;
5932                 if (is_declaration(entity)) {
5933                         return entity->declaration.type;
5934                 } else if (entity->kind == ENTITY_ENUM_VALUE) {
5935                         return entity->enum_value.enum_type;
5936                 } else {
5937                         panic("no declaration or enum in reference");
5938                 }
5939         }
5940
5941         case EXPR_SELECT: {
5942                 entity_t *entity = expression->select.compound_entry;
5943                 assert(is_declaration(entity));
5944                 type_t   *type   = entity->declaration.type;
5945                 return get_qualified_type(type, expression->base.type->base.qualifiers);
5946         }
5947
5948         case EXPR_UNARY_DEREFERENCE: {
5949                 const expression_t *const value = expression->unary.value;
5950                 type_t             *const type  = skip_typeref(value->base.type);
5951                 if (!is_type_pointer(type))
5952                         return type_error_type;
5953                 return type->pointer.points_to;
5954         }
5955
5956         case EXPR_ARRAY_ACCESS: {
5957                 const expression_t *array_ref = expression->array_access.array_ref;
5958                 type_t             *type_left = skip_typeref(array_ref->base.type);
5959                 if (!is_type_pointer(type_left))
5960                         return type_error_type;
5961                 return type_left->pointer.points_to;
5962         }
5963
5964         case EXPR_STRING_LITERAL: {
5965                 size_t  const size = get_string_len(&expression->string_literal.value) + 1;
5966                 type_t *const elem = get_unqualified_type(expression->base.type->pointer.points_to);
5967                 return make_array_type(elem, size, TYPE_QUALIFIER_NONE);
5968         }
5969
5970         case EXPR_COMPOUND_LITERAL:
5971                 return expression->compound_literal.type;
5972
5973         default:
5974                 break;
5975         }
5976         return expression->base.type;
5977 }
5978
5979 /**
5980  * Find an entity matching a symbol in a scope.
5981  * Uses current scope if scope is NULL
5982  */
5983 static entity_t *lookup_entity(const scope_t *scope, symbol_t *symbol,
5984                                namespace_tag_t namespc)
5985 {
5986         if (scope == NULL) {
5987                 return get_entity(symbol, namespc);
5988         }
5989
5990         /* we should optimize here, if scope grows above a certain size we should
5991            construct a hashmap here... */
5992         entity_t *entity = scope->entities;
5993         for ( ; entity != NULL; entity = entity->base.next) {
5994                 if (entity->base.symbol == symbol
5995                     && (namespace_tag_t)entity->base.namespc == namespc)
5996                         break;
5997         }
5998
5999         return entity;
6000 }
6001
6002 static entity_t *parse_qualified_identifier(void)
6003 {
6004         /* namespace containing the symbol */
6005         symbol_t      *symbol;
6006         position_t     pos;
6007         const scope_t *lookup_scope = NULL;
6008
6009         if (accept(T_COLONCOLON))
6010                 lookup_scope = &unit->scope;
6011
6012         entity_t *entity;
6013         while (true) {
6014                 symbol = expect_identifier("while parsing identifier", &pos);
6015                 if (!symbol)
6016                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6017
6018                 /* lookup entity */
6019                 entity = lookup_entity(lookup_scope, symbol, NAMESPACE_NORMAL);
6020
6021                 if (!accept(T_COLONCOLON))
6022                         break;
6023
6024                 switch (entity->kind) {
6025                 case ENTITY_NAMESPACE:
6026                         lookup_scope = &entity->namespacee.members;
6027                         break;
6028                 case ENTITY_STRUCT:
6029                 case ENTITY_UNION:
6030                 case ENTITY_CLASS:
6031                         lookup_scope = &entity->compound.members;
6032                         break;
6033                 default:
6034                         errorf(&pos, "'%Y' must be a namespace, class, struct or union (but is a %s)",
6035                                symbol, get_entity_kind_name(entity->kind));
6036
6037                         /* skip further qualifications */
6038                         while (accept(T_IDENTIFIER) && accept(T_COLONCOLON)) {}
6039
6040                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6041                 }
6042         }
6043
6044         if (entity == NULL) {
6045                 if (!strict_mode && token.kind == '(') {
6046                         /* an implicitly declared function */
6047                         entity = create_implicit_function(symbol, &pos);
6048                         warningf(WARN_IMPLICIT_FUNCTION_DECLARATION, &pos, "implicit declaration of '%N'", entity);
6049                 } else {
6050                         errorf(&pos, "unknown identifier '%Y' found.", symbol);
6051                         entity = create_error_entity(symbol, ENTITY_VARIABLE);
6052                 }
6053         }
6054
6055         return entity;
6056 }
6057
6058 static expression_t *parse_reference(void)
6059 {
6060         position_t const pos    = *HERE;
6061         entity_t  *const entity = parse_qualified_identifier();
6062
6063         type_t *orig_type;
6064         if (is_declaration(entity)) {
6065                 orig_type = entity->declaration.type;
6066         } else if (entity->kind == ENTITY_ENUM_VALUE) {
6067                 orig_type = entity->enum_value.enum_type;
6068         } else {
6069                 panic("expected declaration or enum value in reference");
6070         }
6071
6072         /* we always do the auto-type conversions; the & and sizeof parser contains
6073          * code to revert this! */
6074         type_t *type = automatic_type_conversion(orig_type);
6075
6076         expression_kind_t kind = EXPR_REFERENCE;
6077         if (entity->kind == ENTITY_ENUM_VALUE)
6078                 kind = EXPR_ENUM_CONSTANT;
6079
6080         expression_t *expression     = allocate_expression_zero(kind);
6081         expression->base.pos         = pos;
6082         expression->base.type        = type;
6083         expression->reference.entity = entity;
6084
6085         /* this declaration is used */
6086         if (is_declaration(entity)) {
6087                 entity->declaration.used = true;
6088         }
6089
6090         if (entity->base.parent_scope != file_scope
6091                 && (current_function != NULL
6092                         && entity->base.parent_scope->depth < current_function->parameters.depth)
6093                 && (entity->kind == ENTITY_VARIABLE || entity->kind == ENTITY_PARAMETER)) {
6094                 /* access of a variable from an outer function */
6095                 entity->variable.address_taken = true;
6096                 current_function->need_closure = true;
6097         }
6098
6099         check_deprecated(&pos, entity);
6100
6101         return expression;
6102 }
6103
6104 static bool semantic_cast(expression_t *cast)
6105 {
6106         expression_t     *expression      = cast->unary.value;
6107         type_t           *orig_dest_type  = cast->base.type;
6108         type_t           *orig_type_right = expression->base.type;
6109         type_t     const *dst_type        = skip_typeref(orig_dest_type);
6110         type_t     const *src_type        = skip_typeref(orig_type_right);
6111         position_t const *pos             = &cast->base.pos;
6112
6113         /* §6.5.4 A (void) cast is explicitly permitted, more for documentation
6114          * than for utility. */
6115         if (is_type_void(dst_type))
6116                 return true;
6117
6118         /* only integer and pointer can be casted to pointer */
6119         if (is_type_pointer(dst_type)  &&
6120             !is_type_pointer(src_type) &&
6121             !is_type_integer(src_type) &&
6122             is_type_valid(src_type)) {
6123                 errorf(pos, "cannot convert type '%T' to a pointer type", orig_type_right);
6124                 return false;
6125         }
6126
6127         if (!is_type_scalar(dst_type) && is_type_valid(dst_type)) {
6128                 errorf(pos, "conversion to non-scalar type '%T' requested", orig_dest_type);
6129                 return false;
6130         }
6131
6132         if (!is_type_scalar(src_type) && is_type_valid(src_type)) {
6133                 errorf(pos, "conversion from non-scalar type '%T' requested", orig_type_right);
6134                 return false;
6135         }
6136
6137         if (is_type_pointer(src_type) && is_type_pointer(dst_type)) {
6138                 type_t *src = skip_typeref(src_type->pointer.points_to);
6139                 type_t *dst = skip_typeref(dst_type->pointer.points_to);
6140                 unsigned missing_qualifiers =
6141                         src->base.qualifiers & ~dst->base.qualifiers;
6142                 if (missing_qualifiers != 0) {
6143                         warningf(WARN_CAST_QUAL, pos, "cast discards qualifiers '%Q' in pointer target type of '%T'", missing_qualifiers, orig_type_right);
6144                 }
6145         }
6146         return true;
6147 }
6148
6149 static void semantic_complex_extract(unary_expression_t *extract)
6150 {
6151         type_t *orig_value_type = extract->value->base.type;
6152         type_t *value_type      = skip_typeref(orig_value_type);
6153         if (!is_type_valid(value_type)) {
6154                 extract->base.type = type_error_type;
6155                 return;
6156         }
6157
6158         type_t *type = value_type;
6159         if (!is_type_complex(type)) {
6160                 if (!is_type_arithmetic(type)) {
6161                         errorf(&extract->base.pos,
6162                                    "%s requires an argument with complex or arithmetic type, got '%T'",
6163                                    extract->base.kind == EXPR_UNARY_IMAG ? "__imag__" : "__real__",
6164                                    orig_value_type);
6165                         extract->base.type = type_error_type;
6166                         return;
6167                 }
6168                 atomic_type_kind_t const akind = get_arithmetic_akind(type);
6169                 type = make_complex_type(akind, TYPE_QUALIFIER_NONE);
6170                 extract->value = create_implicit_cast(extract->value, type);
6171         }
6172         assert(type->kind == TYPE_COMPLEX);
6173         type = make_atomic_type(type->atomic.akind, TYPE_QUALIFIER_NONE);
6174         extract->base.type = type;
6175 }
6176
6177 static expression_t *parse_compound_literal(position_t const *const pos,
6178                                             type_t *type)
6179 {
6180         expression_t *expression = allocate_expression_zero(EXPR_COMPOUND_LITERAL);
6181         expression->base.pos = *pos;
6182         bool global_scope = current_scope == file_scope;
6183
6184         parse_initializer_env_t env;
6185         env.type             = type;
6186         env.entity           = NULL;
6187         env.must_be_constant = global_scope;
6188         initializer_t *initializer = parse_initializer(&env);
6189         type = env.type;
6190
6191         expression->base.type                     = automatic_type_conversion(type);
6192         expression->compound_literal.initializer  = initializer;
6193         expression->compound_literal.type         = type;
6194         expression->compound_literal.global_scope = global_scope;
6195
6196         return expression;
6197 }
6198
6199 /**
6200  * Parse a cast expression.
6201  */
6202 static expression_t *parse_cast(void)
6203 {
6204         position_t const pos = *HERE;
6205
6206         eat('(');
6207         add_anchor_token(')');
6208
6209         type_t *type = parse_typename();
6210
6211         rem_anchor_token(')');
6212         expect(')');
6213
6214         if (token.kind == '{') {
6215                 return parse_compound_literal(&pos, type);
6216         }
6217
6218         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
6219         cast->base.pos     = pos;
6220
6221         expression_t *value = parse_subexpression(PREC_CAST);
6222         cast->base.type   = type;
6223         cast->unary.value = value;
6224
6225         if (!semantic_cast(cast)) {
6226                 cast->base.type = type_error_type;
6227         }
6228
6229         return cast;
6230 }
6231
6232 static expression_t *parse_complex_extract_expression(expression_kind_t const kind)
6233 {
6234         expression_t *extract = allocate_expression_zero(kind);
6235         next_token();
6236
6237         extract->unary.value = parse_subexpression(PREC_CAST);
6238         semantic_complex_extract(&extract->unary);
6239         return extract;
6240 }
6241
6242 /**
6243  * Parse a statement expression.
6244  */
6245 static expression_t *parse_statement_expression(void)
6246 {
6247         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
6248
6249         eat('(');
6250         add_anchor_token(')');
6251
6252         statement_t *statement          = parse_compound_statement(true);
6253         statement->compound.stmt_expr   = true;
6254         expression->statement.statement = statement;
6255
6256         /* find last statement and use its type */
6257         type_t *type = type_void;
6258         const statement_t *stmt = statement->compound.statements;
6259         if (stmt != NULL) {
6260                 while (stmt->base.next != NULL)
6261                         stmt = stmt->base.next;
6262
6263                 if (stmt->kind == STATEMENT_EXPRESSION) {
6264                         type = stmt->expression.expression->base.type;
6265                 }
6266         } else {
6267                 position_t const *const pos = &expression->base.pos;
6268                 warningf(WARN_OTHER, pos, "empty statement expression ({})");
6269         }
6270         expression->base.type = type;
6271
6272         rem_anchor_token(')');
6273         expect(')');
6274         return expression;
6275 }
6276
6277 /**
6278  * Parse a parenthesized expression.
6279  */
6280 static expression_t *parse_parenthesized_expression(void)
6281 {
6282         token_t const* const la1 = look_ahead(1);
6283         switch (la1->kind) {
6284         case '{':
6285                 /* gcc extension: a statement expression */
6286                 return parse_statement_expression();
6287
6288         case T_IDENTIFIER:
6289                 if (is_typedef_symbol(la1->base.symbol)) {
6290         DECLARATION_START
6291                         return parse_cast();
6292                 }
6293         }
6294
6295         eat('(');
6296         add_anchor_token(')');
6297         expression_t *result = parse_expression();
6298         result->base.parenthesized = true;
6299         rem_anchor_token(')');
6300         expect(')');
6301
6302         return result;
6303 }
6304
6305 static expression_t *parse_function_keyword(funcname_kind_t const kind)
6306 {
6307         if (current_function == NULL) {
6308                 errorf(HERE, "%K used outside of a function", &token);
6309         }
6310
6311         expression_t *expression  = allocate_expression_zero(EXPR_FUNCNAME);
6312         expression->base.type     = type_char_ptr;
6313         expression->funcname.kind = kind;
6314
6315         next_token();
6316
6317         return expression;
6318 }
6319
6320 static designator_t *parse_designator(void)
6321 {
6322         designator_t *const result = allocate_ast_zero(sizeof(result[0]));
6323         result->symbol = expect_identifier("while parsing member designator", &result->pos);
6324         if (!result->symbol)
6325                 return NULL;
6326
6327         designator_t *last_designator = result;
6328         while (true) {
6329                 if (accept('.')) {
6330                         designator_t *const designator = allocate_ast_zero(sizeof(result[0]));
6331                         designator->symbol = expect_identifier("while parsing member designator", &designator->pos);
6332                         if (!designator->symbol)
6333                                 return NULL;
6334
6335                         last_designator->next = designator;
6336                         last_designator       = designator;
6337                         continue;
6338                 }
6339                 if (accept('[')) {
6340                         add_anchor_token(']');
6341                         designator_t *designator = allocate_ast_zero(sizeof(result[0]));
6342                         designator->pos          = *HERE;
6343                         designator->array_index  = parse_expression();
6344                         rem_anchor_token(']');
6345                         expect(']');
6346
6347                         last_designator->next = designator;
6348                         last_designator       = designator;
6349                         continue;
6350                 }
6351                 break;
6352         }
6353
6354         return result;
6355 }
6356
6357 /**
6358  * Parse the __builtin_offsetof() expression.
6359  */
6360 static expression_t *parse_offsetof(void)
6361 {
6362         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
6363         expression->base.type    = type_size_t;
6364
6365         eat(T___builtin_offsetof);
6366
6367         add_anchor_token(')');
6368         add_anchor_token(',');
6369         expect('(');
6370         type_t *type = parse_typename();
6371         rem_anchor_token(',');
6372         expect(',');
6373         designator_t *designator = parse_designator();
6374         rem_anchor_token(')');
6375         expect(')');
6376
6377         expression->offsetofe.type       = type;
6378         expression->offsetofe.designator = designator;
6379
6380         type_path_t path;
6381         memset(&path, 0, sizeof(path));
6382         path.top_type = type;
6383         path.path     = NEW_ARR_F(type_path_entry_t, 0);
6384
6385         descend_into_subtype(&path);
6386
6387         if (!walk_designator(&path, designator, true)) {
6388                 return create_error_expression();
6389         }
6390
6391         DEL_ARR_F(path.path);
6392
6393         return expression;
6394 }
6395
6396 static bool is_last_parameter(expression_t *const param)
6397 {
6398         if (param->kind == EXPR_REFERENCE) {
6399                 entity_t *const entity = param->reference.entity;
6400                 if (entity->kind == ENTITY_PARAMETER &&
6401                     !entity->base.next               &&
6402                     entity->base.parent_scope == &current_function->parameters) {
6403                         return true;
6404                 }
6405         }
6406
6407         if (!is_type_valid(skip_typeref(param->base.type)))
6408                 return true;
6409
6410         return false;
6411 }
6412
6413 /**
6414  * Parses a __builtin_va_start() expression.
6415  */
6416 static expression_t *parse_va_start(void)
6417 {
6418         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
6419
6420         eat(T___builtin_va_start);
6421
6422         add_anchor_token(')');
6423         add_anchor_token(',');
6424         expect('(');
6425         expression->va_starte.ap = parse_assignment_expression();
6426         rem_anchor_token(',');
6427         expect(',');
6428         expression_t *const param = parse_assignment_expression();
6429         expression->va_starte.parameter = param;
6430         rem_anchor_token(')');
6431         expect(')');
6432
6433         if (!current_function) {
6434                 errorf(&expression->base.pos, "'va_start' used outside of function");
6435         } else if (!current_function->base.type->function.variadic) {
6436                 errorf(&expression->base.pos, "'va_start' used in non-variadic function");
6437         } else if (!is_last_parameter(param)) {
6438                 errorf(&param->base.pos, "second argument of 'va_start' must be last parameter of the current function");
6439         }
6440
6441         return expression;
6442 }
6443
6444 /**
6445  * Parses a __builtin_va_arg() expression.
6446  */
6447 static expression_t *parse_va_arg(void)
6448 {
6449         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
6450
6451         eat(T___builtin_va_arg);
6452
6453         add_anchor_token(')');
6454         add_anchor_token(',');
6455         expect('(');
6456         call_argument_t ap;
6457         ap.expression = parse_assignment_expression();
6458         expression->va_arge.ap = ap.expression;
6459         check_call_argument(type_valist, &ap, 1);
6460
6461         rem_anchor_token(',');
6462         expect(',');
6463         expression->base.type = parse_typename();
6464         rem_anchor_token(')');
6465         expect(')');
6466
6467         return expression;
6468 }
6469
6470 /**
6471  * Parses a __builtin_va_copy() expression.
6472  */
6473 static expression_t *parse_va_copy(void)
6474 {
6475         expression_t *expression = allocate_expression_zero(EXPR_VA_COPY);
6476
6477         eat(T___builtin_va_copy);
6478
6479         add_anchor_token(')');
6480         add_anchor_token(',');
6481         expect('(');
6482         expression_t *dst = parse_assignment_expression();
6483         assign_error_t error = semantic_assign(type_valist, dst);
6484         report_assign_error(error, type_valist, dst, "call argument 1",
6485                             &dst->base.pos);
6486         expression->va_copye.dst = dst;
6487
6488         rem_anchor_token(',');
6489         expect(',');
6490
6491         call_argument_t src;
6492         src.expression = parse_assignment_expression();
6493         check_call_argument(type_valist, &src, 2);
6494         expression->va_copye.src = src.expression;
6495         rem_anchor_token(')');
6496         expect(')');
6497
6498         return expression;
6499 }
6500
6501 /**
6502  * Parses a __builtin_constant_p() expression.
6503  */
6504 static expression_t *parse_builtin_constant(void)
6505 {
6506         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
6507
6508         eat(T___builtin_constant_p);
6509
6510         add_anchor_token(')');
6511         expect('(');
6512         expression->builtin_constant.value = parse_expression();
6513         rem_anchor_token(')');
6514         expect(')');
6515         expression->base.type = type_int;
6516
6517         return expression;
6518 }
6519
6520 /**
6521  * Parses a __builtin_types_compatible_p() expression.
6522  */
6523 static expression_t *parse_builtin_types_compatible(void)
6524 {
6525         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_TYPES_COMPATIBLE_P);
6526
6527         eat(T___builtin_types_compatible_p);
6528
6529         add_anchor_token(')');
6530         add_anchor_token(',');
6531         expect('(');
6532         expression->builtin_types_compatible.left = parse_typename();
6533         rem_anchor_token(',');
6534         expect(',');
6535         expression->builtin_types_compatible.right = parse_typename();
6536         rem_anchor_token(')');
6537         expect(')');
6538         expression->base.type = type_int;
6539
6540         return expression;
6541 }
6542
6543 /**
6544  * Parses a __builtin_is_*() compare expression.
6545  */
6546 static expression_t *parse_compare_builtin(void)
6547 {
6548         expression_kind_t kind;
6549         switch (token.kind) {
6550         case T___builtin_isgreater:      kind = EXPR_BINARY_ISGREATER;      break;
6551         case T___builtin_isgreaterequal: kind = EXPR_BINARY_ISGREATEREQUAL; break;
6552         case T___builtin_isless:         kind = EXPR_BINARY_ISLESS;         break;
6553         case T___builtin_islessequal:    kind = EXPR_BINARY_ISLESSEQUAL;    break;
6554         case T___builtin_islessgreater:  kind = EXPR_BINARY_ISLESSGREATER;  break;
6555         case T___builtin_isunordered:    kind = EXPR_BINARY_ISUNORDERED;    break;
6556         default: internal_errorf(HERE, "invalid compare builtin found");
6557         }
6558         expression_t *const expression = allocate_expression_zero(kind);
6559         next_token();
6560
6561         add_anchor_token(')');
6562         add_anchor_token(',');
6563         expect('(');
6564         expression->binary.left = parse_assignment_expression();
6565         rem_anchor_token(',');
6566         expect(',');
6567         expression->binary.right = parse_assignment_expression();
6568         rem_anchor_token(')');
6569         expect(')');
6570
6571         type_t *const orig_type_left  = expression->binary.left->base.type;
6572         type_t *const orig_type_right = expression->binary.right->base.type;
6573
6574         type_t *const type_left  = skip_typeref(orig_type_left);
6575         type_t *const type_right = skip_typeref(orig_type_right);
6576         if (!is_type_float(type_left) && !is_type_float(type_right)) {
6577                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
6578                         type_error_incompatible("invalid operands in comparison",
6579                                 &expression->base.pos, orig_type_left, orig_type_right);
6580                 }
6581         } else {
6582                 semantic_comparison(&expression->binary, true);
6583         }
6584
6585         return expression;
6586 }
6587
6588 /**
6589  * Parses a MS assume() expression.
6590  */
6591 static expression_t *parse_assume(void)
6592 {
6593         expression_t *expression = allocate_expression_zero(EXPR_UNARY_ASSUME);
6594
6595         eat(T__assume);
6596
6597         add_anchor_token(')');
6598         expect('(');
6599         expression->unary.value = parse_expression();
6600         rem_anchor_token(')');
6601         expect(')');
6602
6603         expression->base.type = type_void;
6604         return expression;
6605 }
6606
6607 /**
6608  * Return the label for the current symbol or create a new one.
6609  */
6610 static label_t *get_label(char const *const context)
6611 {
6612         assert(current_function != NULL);
6613
6614         symbol_t *const sym = expect_identifier(context, NULL);
6615         if (!sym)
6616                 return NULL;
6617
6618         entity_t *label = get_entity(sym, NAMESPACE_LABEL);
6619         /* If we find a local label, we already created the declaration. */
6620         if (label != NULL && label->kind == ENTITY_LOCAL_LABEL) {
6621                 if (label->base.parent_scope != current_scope) {
6622                         assert(label->base.parent_scope->depth < current_scope->depth);
6623                         current_function->goto_to_outer = true;
6624                 }
6625         } else if (label == NULL || label->base.parent_scope != &current_function->parameters) {
6626                 /* There is no matching label in the same function, so create a new one. */
6627                 position_t const nowhere = { NULL, 0, 0, false };
6628                 label = allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym, &nowhere);
6629                 label_push(label);
6630         }
6631
6632         return &label->label;
6633 }
6634
6635 /**
6636  * Parses a GNU && label address expression.
6637  */
6638 static expression_t *parse_label_address(void)
6639 {
6640         position_t const pos = *HERE;
6641         eat(T_ANDAND);
6642
6643         label_t *const label = get_label("while parsing label address");
6644         if (!label)
6645                 return create_error_expression();
6646
6647         label->used          = true;
6648         label->address_taken = true;
6649
6650         expression_t *expression = allocate_expression_zero(EXPR_LABEL_ADDRESS);
6651         expression->base.pos     = pos;
6652
6653         /* label address is treated as a void pointer */
6654         expression->base.type           = type_void_ptr;
6655         expression->label_address.label = label;
6656         return expression;
6657 }
6658
6659 /**
6660  * Parse a microsoft __noop expression.
6661  */
6662 static expression_t *parse_noop_expression(void)
6663 {
6664         /* the result is a (int)0 */
6665         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_MS_NOOP);
6666         literal->base.type           = type_int;
6667         literal->literal.value.begin = "__noop";
6668         literal->literal.value.size  = 6;
6669
6670         eat(T___noop);
6671
6672         if (token.kind == '(') {
6673                 /* parse arguments */
6674                 eat('(');
6675                 add_anchor_token(')');
6676                 add_anchor_token(',');
6677
6678                 if (token.kind != ')') do {
6679                         (void)parse_assignment_expression();
6680                 } while (accept(','));
6681
6682                 rem_anchor_token(',');
6683                 rem_anchor_token(')');
6684         }
6685         expect(')');
6686
6687         return literal;
6688 }
6689
6690 /**
6691  * Parses a primary expression.
6692  */
6693 static expression_t *parse_primary_expression(void)
6694 {
6695         switch (token.kind) {
6696         case T_false:                        return parse_boolean_literal(false);
6697         case T_true:                         return parse_boolean_literal(true);
6698         case T_NUMBER:                       return parse_number_literal();
6699         case T_CHARACTER_CONSTANT:           return parse_character_constant();
6700         case T_STRING_LITERAL:               return parse_string_literal();
6701         case T___func__:                     return parse_function_keyword(FUNCNAME_FUNCTION);
6702         case T___PRETTY_FUNCTION__:          return parse_function_keyword(FUNCNAME_PRETTY_FUNCTION);
6703         case T___FUNCSIG__:                  return parse_function_keyword(FUNCNAME_FUNCSIG);
6704         case T___FUNCDNAME__:                return parse_function_keyword(FUNCNAME_FUNCDNAME);
6705         case T___builtin_offsetof:           return parse_offsetof();
6706         case T___builtin_va_start:           return parse_va_start();
6707         case T___builtin_va_arg:             return parse_va_arg();
6708         case T___builtin_va_copy:            return parse_va_copy();
6709         case T___builtin_isgreater:
6710         case T___builtin_isgreaterequal:
6711         case T___builtin_isless:
6712         case T___builtin_islessequal:
6713         case T___builtin_islessgreater:
6714         case T___builtin_isunordered:        return parse_compare_builtin();
6715         case T___builtin_constant_p:         return parse_builtin_constant();
6716         case T___builtin_types_compatible_p: return parse_builtin_types_compatible();
6717         case T__assume:                      return parse_assume();
6718         case T_ANDAND:
6719                 if (GNU_MODE)
6720                         return parse_label_address();
6721                 break;
6722
6723         case '(':                            return parse_parenthesized_expression();
6724         case T___noop:                       return parse_noop_expression();
6725         case T___imag__:                     return parse_complex_extract_expression(EXPR_UNARY_IMAG);
6726         case T___real__:                     return parse_complex_extract_expression(EXPR_UNARY_REAL);
6727
6728         /* Gracefully handle type names while parsing expressions. */
6729         case T_COLONCOLON:
6730                 return parse_reference();
6731         case T_IDENTIFIER:
6732                 if (!is_typedef_symbol(token.base.symbol)) {
6733                         return parse_reference();
6734                 }
6735                 /* FALLTHROUGH */
6736         DECLARATION_START {
6737                 position_t const pos = *HERE;
6738                 declaration_specifiers_t specifiers;
6739                 parse_declaration_specifiers(&specifiers);
6740                 type_t const *const type = parse_abstract_declarator(specifiers.type);
6741                 errorf(&pos, "encountered type '%T' while parsing expression", type);
6742                 return create_error_expression();
6743         }
6744         }
6745
6746         errorf(HERE, "unexpected token %K, expected an expression", &token);
6747         eat_until_anchor();
6748         return create_error_expression();
6749 }
6750
6751 static expression_t *parse_array_expression(expression_t *left)
6752 {
6753         expression_t              *const expr = allocate_expression_zero(EXPR_ARRAY_ACCESS);
6754         array_access_expression_t *const arr  = &expr->array_access;
6755
6756         eat('[');
6757         add_anchor_token(']');
6758
6759         expression_t *const inside = parse_expression();
6760
6761         type_t *const orig_type_left   = left->base.type;
6762         type_t *const orig_type_inside = inside->base.type;
6763
6764         type_t *const type_left   = skip_typeref(orig_type_left);
6765         type_t *const type_inside = skip_typeref(orig_type_inside);
6766
6767         expression_t *ref;
6768         expression_t *idx;
6769         type_t       *idx_type;
6770         type_t       *res_type;
6771         if (is_type_pointer(type_left)) {
6772                 ref      = left;
6773                 idx      = inside;
6774                 idx_type = type_inside;
6775                 res_type = type_left->pointer.points_to;
6776                 goto check_idx;
6777         } else if (is_type_pointer(type_inside)) {
6778                 arr->flipped = true;
6779                 ref      = inside;
6780                 idx      = left;
6781                 idx_type = type_left;
6782                 res_type = type_inside->pointer.points_to;
6783 check_idx:
6784                 res_type = automatic_type_conversion(res_type);
6785                 if (!is_type_integer(idx_type)) {
6786                         if (is_type_valid(idx_type))
6787                                 errorf(&idx->base.pos, "array subscript must have integer type");
6788                 } else if (is_type_atomic(idx_type, ATOMIC_TYPE_CHAR)) {
6789                         position_t const *const pos = &idx->base.pos;
6790                         warningf(WARN_CHAR_SUBSCRIPTS, pos, "array subscript has char type");
6791                 }
6792         } else {
6793                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
6794                         errorf(&expr->base.pos, "invalid types '%T[%T]' for array access", orig_type_left, orig_type_inside);
6795                 }
6796                 res_type = type_error_type;
6797                 ref      = left;
6798                 idx      = inside;
6799         }
6800
6801         arr->array_ref = ref;
6802         arr->index     = idx;
6803         arr->base.type = res_type;
6804
6805         rem_anchor_token(']');
6806         expect(']');
6807         return expr;
6808 }
6809
6810 static bool is_bitfield(const expression_t *expression)
6811 {
6812         return expression->kind == EXPR_SELECT
6813                 && expression->select.compound_entry->compound_member.bitfield;
6814 }
6815
6816 static expression_t *parse_typeprop(expression_kind_t const kind)
6817 {
6818         expression_t  *tp_expression = allocate_expression_zero(kind);
6819         tp_expression->base.type     = type_size_t;
6820
6821         eat(kind == EXPR_SIZEOF ? T_sizeof : T__Alignof);
6822
6823         type_t       *orig_type;
6824         expression_t *expression;
6825         if (token.kind == '(' && is_declaration_specifier(look_ahead(1))) {
6826                 position_t const pos = *HERE;
6827                 eat('(');
6828                 add_anchor_token(')');
6829                 orig_type = parse_typename();
6830                 rem_anchor_token(')');
6831                 expect(')');
6832
6833                 if (token.kind == '{') {
6834                         /* It was not sizeof(type) after all.  It is sizeof of an expression
6835                          * starting with a compound literal */
6836                         expression = parse_compound_literal(&pos, orig_type);
6837                         goto typeprop_expression;
6838                 }
6839         } else {
6840                 expression = parse_subexpression(PREC_UNARY);
6841
6842 typeprop_expression:
6843                 if (is_bitfield(expression)) {
6844                         char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6845                         errorf(&tp_expression->base.pos,
6846                                    "operand of %s expression must not be a bitfield", what);
6847                 }
6848
6849                 tp_expression->typeprop.tp_expression = expression;
6850
6851                 orig_type = revert_automatic_type_conversion(expression);
6852                 expression->base.type = orig_type;
6853         }
6854
6855         tp_expression->typeprop.type   = orig_type;
6856         type_t const* const type       = skip_typeref(orig_type);
6857         char   const*       wrong_type = NULL;
6858         if (is_type_incomplete(type)) {
6859                 if (!is_type_void(type) || !GNU_MODE)
6860                         wrong_type = "incomplete";
6861         } else if (type->kind == TYPE_FUNCTION) {
6862                 if (GNU_MODE) {
6863                         /* function types are allowed (and return 1) */
6864                         position_t const *const pos  = &tp_expression->base.pos;
6865                         char       const *const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6866                         warningf(WARN_OTHER, pos, "%s expression with function argument returns invalid result", what);
6867                 } else {
6868                         wrong_type = "function";
6869                 }
6870         }
6871
6872         if (wrong_type != NULL) {
6873                 char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6874                 errorf(&tp_expression->base.pos,
6875                                 "operand of %s expression must not be of %s type '%T'",
6876                                 what, wrong_type, orig_type);
6877         }
6878
6879         return tp_expression;
6880 }
6881
6882 static expression_t *parse_sizeof(void)
6883 {
6884         return parse_typeprop(EXPR_SIZEOF);
6885 }
6886
6887 static expression_t *parse_alignof(void)
6888 {
6889         return parse_typeprop(EXPR_ALIGNOF);
6890 }
6891
6892 static expression_t *parse_select_expression(expression_t *addr)
6893 {
6894         assert(token.kind == '.' || token.kind == T_MINUSGREATER);
6895         bool select_left_arrow = (token.kind == T_MINUSGREATER);
6896         position_t const pos = *HERE;
6897         next_token();
6898
6899         symbol_t *const symbol = expect_identifier("while parsing select", NULL);
6900         if (!symbol)
6901                 return create_error_expression();
6902
6903         type_t *const orig_type = addr->base.type;
6904         type_t *const type      = skip_typeref(orig_type);
6905
6906         type_t *type_left;
6907         bool    saw_error = false;
6908         if (is_type_pointer(type)) {
6909                 if (!select_left_arrow) {
6910                         errorf(&pos,
6911                                "request for member '%Y' in something not a struct or union, but '%T'",
6912                                symbol, orig_type);
6913                         saw_error = true;
6914                 }
6915                 type_left = skip_typeref(type->pointer.points_to);
6916         } else {
6917                 if (select_left_arrow && is_type_valid(type)) {
6918                         errorf(&pos, "left hand side of '->' is not a pointer, but '%T'", orig_type);
6919                         saw_error = true;
6920                 }
6921                 type_left = type;
6922         }
6923
6924         if (!is_type_compound(type_left)) {
6925                 if (is_type_valid(type_left) && !saw_error) {
6926                         errorf(&pos,
6927                                "request for member '%Y' in something not a struct or union, but '%T'",
6928                                symbol, type_left);
6929                 }
6930                 return create_error_expression();
6931         }
6932
6933         compound_t *compound = type_left->compound.compound;
6934         if (!compound->complete) {
6935                 errorf(&pos, "request for member '%Y' in incomplete type '%T'",
6936                        symbol, type_left);
6937                 return create_error_expression();
6938         }
6939
6940         type_qualifiers_t  qualifiers = type_left->base.qualifiers;
6941         expression_t      *result     =
6942                 find_create_select(&pos, addr, qualifiers, compound, symbol);
6943
6944         if (result == NULL) {
6945                 errorf(&pos, "'%T' has no member named '%Y'", orig_type, symbol);
6946                 return create_error_expression();
6947         }
6948
6949         return result;
6950 }
6951
6952 static void check_call_argument(type_t          *expected_type,
6953                                 call_argument_t *argument, unsigned pos)
6954 {
6955         type_t         *expected_type_skip = skip_typeref(expected_type);
6956         assign_error_t  error              = ASSIGN_ERROR_INCOMPATIBLE;
6957         expression_t   *arg_expr           = argument->expression;
6958         type_t         *arg_type           = skip_typeref(arg_expr->base.type);
6959
6960         /* handle transparent union gnu extension */
6961         if (is_type_union(expected_type_skip)
6962                         && (get_type_modifiers(expected_type) & DM_TRANSPARENT_UNION)) {
6963                 compound_t *union_decl  = expected_type_skip->compound.compound;
6964                 type_t     *best_type   = NULL;
6965                 entity_t   *entry       = union_decl->members.entities;
6966                 for ( ; entry != NULL; entry = entry->base.next) {
6967                         assert(is_declaration(entry));
6968                         type_t *decl_type = entry->declaration.type;
6969                         error = semantic_assign(decl_type, arg_expr);
6970                         if (error == ASSIGN_ERROR_INCOMPATIBLE
6971                                 || error == ASSIGN_ERROR_POINTER_QUALIFIER_MISSING)
6972                                 continue;
6973
6974                         if (error == ASSIGN_SUCCESS) {
6975                                 best_type = decl_type;
6976                         } else if (best_type == NULL) {
6977                                 best_type = decl_type;
6978                         }
6979                 }
6980
6981                 if (best_type != NULL) {
6982                         expected_type = best_type;
6983                 }
6984         }
6985
6986         error                = semantic_assign(expected_type, arg_expr);
6987         argument->expression = create_implicit_cast(arg_expr, expected_type);
6988
6989         if (error != ASSIGN_SUCCESS) {
6990                 /* report exact scope in error messages (like "in argument 3") */
6991                 char buf[64];
6992                 snprintf(buf, sizeof(buf), "call argument %u", pos);
6993                 report_assign_error(error, expected_type, arg_expr, buf,
6994                                     &arg_expr->base.pos);
6995         } else {
6996                 type_t *const promoted_type = get_default_promoted_type(arg_type);
6997                 if (!types_compatible(expected_type_skip, promoted_type) &&
6998                     !types_compatible(expected_type_skip, type_void_ptr) &&
6999                     !types_compatible(type_void_ptr,      promoted_type)) {
7000                         /* Deliberately show the skipped types in this warning */
7001                         position_t const *const apos = &arg_expr->base.pos;
7002                         warningf(WARN_TRADITIONAL, apos, "passing call argument %u as '%T' rather than '%T' due to prototype", pos, expected_type_skip, promoted_type);
7003                 }
7004         }
7005 }
7006
7007 /**
7008  * Handle the semantic restrictions of builtin calls
7009  */
7010 static void handle_builtin_argument_restrictions(call_expression_t *call)
7011 {
7012         entity_t *entity = call->function->reference.entity;
7013         switch (entity->function.btk) {
7014         case BUILTIN_FIRM:
7015                 switch (entity->function.b.firm_builtin_kind) {
7016                 case ir_bk_return_address:
7017                 case ir_bk_frame_address: {
7018                         /* argument must be constant */
7019                         call_argument_t *argument = call->arguments;
7020
7021                         if (is_constant_expression(argument->expression) == EXPR_CLASS_VARIABLE) {
7022                                 errorf(&call->base.pos,
7023                                            "argument of '%Y' must be a constant expression",
7024                                            call->function->reference.entity->base.symbol);
7025                         }
7026                         break;
7027                 }
7028                 case ir_bk_prefetch:
7029                         /* second and third argument must be constant if existent */
7030                         if (call->arguments == NULL)
7031                                 break;
7032                         call_argument_t *rw = call->arguments->next;
7033                         call_argument_t *locality = NULL;
7034
7035                         if (rw != NULL) {
7036                                 if (is_constant_expression(rw->expression) == EXPR_CLASS_VARIABLE) {
7037                                         errorf(&call->base.pos,
7038                                                    "second argument of '%Y' must be a constant expression",
7039                                                    call->function->reference.entity->base.symbol);
7040                                 }
7041                                 locality = rw->next;
7042                         }
7043                         if (locality != NULL) {
7044                                 if (is_constant_expression(locality->expression) == EXPR_CLASS_VARIABLE) {
7045                                         errorf(&call->base.pos,
7046                                                    "third argument of '%Y' must be a constant expression",
7047                                                    call->function->reference.entity->base.symbol);
7048                                 }
7049                         }
7050                         break;
7051                 default:
7052                         break;
7053                 }
7054
7055         case BUILTIN_OBJECT_SIZE:
7056                 if (call->arguments == NULL)
7057                         break;
7058
7059                 call_argument_t *arg = call->arguments->next;
7060                 if (arg != NULL && is_constant_expression(arg->expression) == EXPR_CLASS_VARIABLE) {
7061                         errorf(&call->base.pos,
7062                                    "second argument of '%Y' must be a constant expression",
7063                                    call->function->reference.entity->base.symbol);
7064                 }
7065                 break;
7066         default:
7067                 break;
7068         }
7069 }
7070
7071 /**
7072  * Parse a call expression, i.e. expression '( ... )'.
7073  *
7074  * @param expression  the function address
7075  */
7076 static expression_t *parse_call_expression(expression_t *expression)
7077 {
7078         expression_t      *result = allocate_expression_zero(EXPR_CALL);
7079         call_expression_t *call   = &result->call;
7080         call->function            = expression;
7081
7082         type_t *const orig_type = expression->base.type;
7083         type_t *const type      = skip_typeref(orig_type);
7084
7085         function_type_t *function_type = NULL;
7086         if (is_type_pointer(type)) {
7087                 type_t *const to_type = skip_typeref(type->pointer.points_to);
7088
7089                 if (is_type_function(to_type)) {
7090                         function_type   = &to_type->function;
7091                         call->base.type = function_type->return_type;
7092                 }
7093         }
7094
7095         if (function_type == NULL && is_type_valid(type)) {
7096                 errorf(HERE,
7097                        "called object '%E' (type '%T') is not a pointer to a function",
7098                        expression, orig_type);
7099         }
7100
7101         /* parse arguments */
7102         eat('(');
7103         add_anchor_token(')');
7104         add_anchor_token(',');
7105
7106         if (token.kind != ')') {
7107                 call_argument_t **anchor = &call->arguments;
7108                 do {
7109                         call_argument_t *argument = allocate_ast_zero(sizeof(*argument));
7110                         argument->expression = parse_assignment_expression();
7111
7112                         *anchor = argument;
7113                         anchor  = &argument->next;
7114                 } while (accept(','));
7115         }
7116         rem_anchor_token(',');
7117         rem_anchor_token(')');
7118         expect(')');
7119
7120         if (function_type == NULL)
7121                 return result;
7122
7123         /* check type and count of call arguments */
7124         function_parameter_t *parameter = function_type->parameters;
7125         call_argument_t      *argument  = call->arguments;
7126         if (!function_type->unspecified_parameters) {
7127                 for (unsigned pos = 0; parameter != NULL && argument != NULL;
7128                                 parameter = parameter->next, argument = argument->next) {
7129                         check_call_argument(parameter->type, argument, ++pos);
7130                 }
7131
7132                 if (parameter != NULL) {
7133                         errorf(&expression->base.pos, "too few arguments to function '%E'",
7134                                expression);
7135                 } else if (argument != NULL && !function_type->variadic) {
7136                         errorf(&argument->expression->base.pos,
7137                                "too many arguments to function '%E'", expression);
7138                 }
7139         }
7140
7141         /* do default promotion for other arguments */
7142         for (; argument != NULL; argument = argument->next) {
7143                 type_t *argument_type = argument->expression->base.type;
7144                 if (!is_type_object(skip_typeref(argument_type))) {
7145                         errorf(&argument->expression->base.pos,
7146                                "call argument '%E' must not be void", argument->expression);
7147                 }
7148
7149                 argument_type = get_default_promoted_type(argument_type);
7150
7151                 argument->expression
7152                         = create_implicit_cast(argument->expression, argument_type);
7153         }
7154
7155         check_format(call);
7156
7157         if (is_type_compound(skip_typeref(function_type->return_type))) {
7158                 position_t const *const pos = &expression->base.pos;
7159                 warningf(WARN_AGGREGATE_RETURN, pos, "function call has aggregate value");
7160         }
7161
7162         if (expression->kind == EXPR_REFERENCE) {
7163                 reference_expression_t *reference = &expression->reference;
7164                 if (reference->entity->kind == ENTITY_FUNCTION &&
7165                     reference->entity->function.btk != BUILTIN_NONE)
7166                         handle_builtin_argument_restrictions(call);
7167         }
7168
7169         return result;
7170 }
7171
7172 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
7173
7174 static bool same_compound_type(const type_t *type1, const type_t *type2)
7175 {
7176         return
7177                 is_type_compound(type1) &&
7178                 type1->kind == type2->kind &&
7179                 type1->compound.compound == type2->compound.compound;
7180 }
7181
7182 static expression_t const *get_reference_address(expression_t const *expr)
7183 {
7184         bool regular_take_address = true;
7185         for (;;) {
7186                 if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7187                         expr = expr->unary.value;
7188                 } else {
7189                         regular_take_address = false;
7190                 }
7191
7192                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7193                         break;
7194
7195                 expr = expr->unary.value;
7196         }
7197
7198         if (expr->kind != EXPR_REFERENCE)
7199                 return NULL;
7200
7201         /* special case for functions which are automatically converted to a
7202          * pointer to function without an extra TAKE_ADDRESS operation */
7203         if (!regular_take_address &&
7204                         expr->reference.entity->kind != ENTITY_FUNCTION) {
7205                 return NULL;
7206         }
7207
7208         return expr;
7209 }
7210
7211 static void warn_reference_address_as_bool(expression_t const* expr)
7212 {
7213         expr = get_reference_address(expr);
7214         if (expr != NULL) {
7215                 position_t const *const pos = &expr->base.pos;
7216                 entity_t   const *const ent = expr->reference.entity;
7217                 warningf(WARN_ADDRESS, pos, "the address of '%N' will always evaluate as 'true'", ent);
7218         }
7219 }
7220
7221 static void warn_assignment_in_condition(const expression_t *const expr)
7222 {
7223         if (expr->base.kind != EXPR_BINARY_ASSIGN)
7224                 return;
7225         if (expr->base.parenthesized)
7226                 return;
7227         position_t const *const pos = &expr->base.pos;
7228         warningf(WARN_PARENTHESES, pos, "suggest parentheses around assignment used as truth value");
7229 }
7230
7231 static void semantic_condition(expression_t const *const expr,
7232                                char const *const context)
7233 {
7234         type_t *const type = skip_typeref(expr->base.type);
7235         if (is_type_scalar(type)) {
7236                 warn_reference_address_as_bool(expr);
7237                 warn_assignment_in_condition(expr);
7238         } else if (is_type_valid(type)) {
7239                 errorf(&expr->base.pos, "%s must have scalar type", context);
7240         }
7241 }
7242
7243 /**
7244  * Parse a conditional expression, i.e. 'expression ? ... : ...'.
7245  *
7246  * @param expression  the conditional expression
7247  */
7248 static expression_t *parse_conditional_expression(expression_t *expression)
7249 {
7250         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
7251
7252         conditional_expression_t *conditional = &result->conditional;
7253         conditional->condition                = expression;
7254
7255         eat('?');
7256         add_anchor_token(':');
7257
7258         /* §6.5.15:2  The first operand shall have scalar type. */
7259         semantic_condition(expression, "condition of conditional operator");
7260
7261         expression_t *true_expression = expression;
7262         bool          gnu_cond = false;
7263         if (GNU_MODE && token.kind == ':') {
7264                 gnu_cond = true;
7265         } else {
7266                 true_expression = parse_expression();
7267         }
7268         rem_anchor_token(':');
7269         expect(':');
7270         expression_t *false_expression =
7271                 parse_subexpression(c_mode & _CXX ? PREC_ASSIGNMENT : PREC_CONDITIONAL);
7272
7273         type_t *const orig_true_type  = true_expression->base.type;
7274         type_t *const orig_false_type = false_expression->base.type;
7275         type_t *const true_type       = skip_typeref(orig_true_type);
7276         type_t *const false_type      = skip_typeref(orig_false_type);
7277
7278         /* 6.5.15.3 */
7279         position_t const *const pos = &conditional->base.pos;
7280         type_t                 *result_type;
7281         if (is_type_void(true_type) || is_type_void(false_type)) {
7282                 /* ISO/IEC 14882:1998(E) §5.16:2 */
7283                 if (true_expression->kind == EXPR_UNARY_THROW) {
7284                         result_type = false_type;
7285                 } else if (false_expression->kind == EXPR_UNARY_THROW) {
7286                         result_type = true_type;
7287                 } else {
7288                         if (!is_type_void(true_type) || !is_type_void(false_type)) {
7289                                 warningf(WARN_OTHER, pos, "ISO C forbids conditional expression with only one void side");
7290                         }
7291                         result_type = type_void;
7292                 }
7293         } else if (is_type_arithmetic(true_type)
7294                    && is_type_arithmetic(false_type)) {
7295                 result_type = semantic_arithmetic(true_type, false_type);
7296         } else if (same_compound_type(true_type, false_type)) {
7297                 /* just take 1 of the 2 types */
7298                 result_type = true_type;
7299         } else if (is_type_pointer(true_type) || is_type_pointer(false_type)) {
7300                 type_t *pointer_type;
7301                 type_t *other_type;
7302                 expression_t *other_expression;
7303                 if (is_type_pointer(true_type) &&
7304                                 (!is_type_pointer(false_type) || is_null_pointer_constant(false_expression))) {
7305                         pointer_type     = true_type;
7306                         other_type       = false_type;
7307                         other_expression = false_expression;
7308                 } else {
7309                         pointer_type     = false_type;
7310                         other_type       = true_type;
7311                         other_expression = true_expression;
7312                 }
7313
7314                 if (is_null_pointer_constant(other_expression)) {
7315                         result_type = pointer_type;
7316                 } else if (is_type_pointer(other_type)) {
7317                         type_t *to1 = skip_typeref(pointer_type->pointer.points_to);
7318                         type_t *to2 = skip_typeref(other_type->pointer.points_to);
7319
7320                         type_t *to;
7321                         if (is_type_void(to1) || is_type_void(to2)) {
7322                                 to = type_void;
7323                         } else if (types_compatible(get_unqualified_type(to1),
7324                                                     get_unqualified_type(to2))) {
7325                                 to = to1;
7326                         } else {
7327                                 warningf(WARN_OTHER, pos, "pointer types '%T' and '%T' in conditional expression are incompatible", true_type, false_type);
7328                                 to = type_void;
7329                         }
7330
7331                         type_t *const type =
7332                                 get_qualified_type(to, to1->base.qualifiers | to2->base.qualifiers);
7333                         result_type = make_pointer_type(type, TYPE_QUALIFIER_NONE);
7334                 } else if (is_type_integer(other_type)) {
7335                         warningf(WARN_OTHER, pos, "pointer/integer type mismatch in conditional expression ('%T' and '%T')", true_type, false_type);
7336                         result_type = pointer_type;
7337                 } else {
7338                         goto types_incompatible;
7339                 }
7340         } else {
7341 types_incompatible:
7342                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
7343                         type_error_incompatible("while parsing conditional", pos, true_type, false_type);
7344                 }
7345                 result_type = type_error_type;
7346         }
7347
7348         conditional->true_expression
7349                 = gnu_cond ? NULL : create_implicit_cast(true_expression, result_type);
7350         conditional->false_expression
7351                 = create_implicit_cast(false_expression, result_type);
7352         conditional->base.type = result_type;
7353         return result;
7354 }
7355
7356 /**
7357  * Parse an extension expression.
7358  */
7359 static expression_t *parse_extension(void)
7360 {
7361         PUSH_EXTENSION();
7362         expression_t *expression = parse_subexpression(PREC_UNARY);
7363         POP_EXTENSION();
7364         return expression;
7365 }
7366
7367 /**
7368  * Parse a __builtin_classify_type() expression.
7369  */
7370 static expression_t *parse_builtin_classify_type(void)
7371 {
7372         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
7373         result->base.type    = type_int;
7374
7375         eat(T___builtin_classify_type);
7376
7377         add_anchor_token(')');
7378         expect('(');
7379         expression_t *expression = parse_expression();
7380         rem_anchor_token(')');
7381         expect(')');
7382         result->classify_type.type_expression = expression;
7383
7384         return result;
7385 }
7386
7387 /**
7388  * Parse a delete expression
7389  * ISO/IEC 14882:1998(E) §5.3.5
7390  */
7391 static expression_t *parse_delete(void)
7392 {
7393         expression_t *const result = allocate_expression_zero(EXPR_UNARY_DELETE);
7394         result->base.type          = type_void;
7395
7396         eat(T_delete);
7397
7398         if (accept('[')) {
7399                 result->kind = EXPR_UNARY_DELETE_ARRAY;
7400                 expect(']');
7401         }
7402
7403         expression_t *const value = parse_subexpression(PREC_CAST);
7404         result->unary.value = value;
7405
7406         type_t *const type = skip_typeref(value->base.type);
7407         if (!is_type_pointer(type)) {
7408                 if (is_type_valid(type)) {
7409                         errorf(&value->base.pos,
7410                                         "operand of delete must have pointer type");
7411                 }
7412         } else if (is_type_void(skip_typeref(type->pointer.points_to))) {
7413                 position_t const *const pos = &value->base.pos;
7414                 warningf(WARN_OTHER, pos, "deleting 'void*' is undefined");
7415         }
7416
7417         return result;
7418 }
7419
7420 /**
7421  * Parse a throw expression
7422  * ISO/IEC 14882:1998(E) §15:1
7423  */
7424 static expression_t *parse_throw(void)
7425 {
7426         expression_t *const result = allocate_expression_zero(EXPR_UNARY_THROW);
7427         result->base.type          = type_void;
7428
7429         eat(T_throw);
7430
7431         expression_t *value = NULL;
7432         switch (token.kind) {
7433                 EXPRESSION_START {
7434                         value = parse_assignment_expression();
7435                         /* ISO/IEC 14882:1998(E) §15.1:3 */
7436                         type_t *const orig_type = value->base.type;
7437                         type_t *const type      = skip_typeref(orig_type);
7438                         if (is_type_incomplete(type)) {
7439                                 errorf(&value->base.pos,
7440                                                 "cannot throw object of incomplete type '%T'", orig_type);
7441                         } else if (is_type_pointer(type)) {
7442                                 type_t *const points_to = skip_typeref(type->pointer.points_to);
7443                                 if (is_type_incomplete(points_to) && !is_type_void(points_to)) {
7444                                         errorf(&value->base.pos,
7445                                                         "cannot throw pointer to incomplete type '%T'", orig_type);
7446                                 }
7447                         }
7448                 }
7449
7450                 default:
7451                         break;
7452         }
7453         result->unary.value = value;
7454
7455         return result;
7456 }
7457
7458 static bool check_pointer_arithmetic(const position_t *pos,
7459                                      type_t *pointer_type,
7460                                      type_t *orig_pointer_type)
7461 {
7462         type_t *points_to = pointer_type->pointer.points_to;
7463         points_to = skip_typeref(points_to);
7464
7465         if (is_type_incomplete(points_to)) {
7466                 if (!GNU_MODE || !is_type_void(points_to)) {
7467                         errorf(pos,
7468                                "arithmetic with pointer to incomplete type '%T' not allowed",
7469                                orig_pointer_type);
7470                         return false;
7471                 } else {
7472                         warningf(WARN_POINTER_ARITH, pos, "pointer of type '%T' used in arithmetic", orig_pointer_type);
7473                 }
7474         } else if (is_type_function(points_to)) {
7475                 if (!GNU_MODE) {
7476                         errorf(pos,
7477                                "arithmetic with pointer to function type '%T' not allowed",
7478                                orig_pointer_type);
7479                         return false;
7480                 } else {
7481                         warningf(WARN_POINTER_ARITH, pos,
7482                                  "pointer to a function '%T' used in arithmetic",
7483                                  orig_pointer_type);
7484                 }
7485         }
7486         return true;
7487 }
7488
7489 static bool is_lvalue(const expression_t *expression)
7490 {
7491         /* TODO: doesn't seem to be consistent with §6.3.2.1:1 */
7492         switch (expression->kind) {
7493         case EXPR_ARRAY_ACCESS:
7494         case EXPR_COMPOUND_LITERAL:
7495         case EXPR_REFERENCE:
7496         case EXPR_SELECT:
7497         case EXPR_UNARY_DEREFERENCE:
7498                 return true;
7499
7500         default: {
7501                 type_t *type = skip_typeref(expression->base.type);
7502                 return
7503                         /* ISO/IEC 14882:1998(E) §3.10:3 */
7504                         is_type_reference(type) ||
7505                         /* Claim it is an lvalue, if the type is invalid.  There was a parse
7506                          * error before, which maybe prevented properly recognizing it as
7507                          * lvalue. */
7508                         !is_type_valid(type);
7509         }
7510         }
7511 }
7512
7513 static void semantic_incdec(unary_expression_t *expression)
7514 {
7515         type_t *orig_type = expression->value->base.type;
7516         type_t *type      = skip_typeref(orig_type);
7517         if (is_type_pointer(type)) {
7518                 if (!check_pointer_arithmetic(&expression->base.pos, type, orig_type)) {
7519                         return;
7520                 }
7521         } else if (!is_type_real(type) &&
7522                    (!GNU_MODE || !is_type_complex(type)) && is_type_valid(type)) {
7523                 /* TODO: improve error message */
7524                 errorf(&expression->base.pos,
7525                        "operation needs an arithmetic or pointer type");
7526                 orig_type = type = type_error_type;
7527         }
7528         if (!is_lvalue(expression->value)) {
7529                 /* TODO: improve error message */
7530                 errorf(&expression->base.pos, "lvalue required as operand");
7531         }
7532         expression->base.type = orig_type;
7533 }
7534
7535 static void promote_unary_int_expr(unary_expression_t *const expr, type_t *const type)
7536 {
7537         atomic_type_kind_t akind = get_arithmetic_akind(type);
7538         type_t *res_type;
7539         if (get_akind_rank(akind) < get_akind_rank(ATOMIC_TYPE_INT)) {
7540                 if (type->kind == TYPE_COMPLEX)
7541                         res_type = make_complex_type(ATOMIC_TYPE_INT, TYPE_QUALIFIER_NONE);
7542                 else
7543                         res_type = type_int;
7544         } else {
7545                 res_type = type;
7546         }
7547         expr->base.type = res_type;
7548         expr->value     = create_implicit_cast(expr->value, res_type);
7549 }
7550
7551 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
7552 {
7553         type_t *const orig_type = expression->value->base.type;
7554         type_t *const type      = skip_typeref(orig_type);
7555         if (!is_type_arithmetic(type)) {
7556                 if (is_type_valid(type)) {
7557                         position_t const *const pos = &expression->base.pos;
7558                         errorf(pos, "operand of unary expression must have arithmetic type, but is '%T'", orig_type);
7559                 }
7560                 return;
7561         } else if (is_type_integer(type)) {
7562                 promote_unary_int_expr(expression, type);
7563         } else {
7564                 expression->base.type = orig_type;
7565         }
7566 }
7567
7568 static void semantic_unexpr_plus(unary_expression_t *expression)
7569 {
7570         semantic_unexpr_arithmetic(expression);
7571         position_t const *const pos = &expression->base.pos;
7572         warningf(WARN_TRADITIONAL, pos, "traditional C rejects the unary plus operator");
7573 }
7574
7575 static void semantic_not(unary_expression_t *expression)
7576 {
7577         /* §6.5.3.3:1  The operand [...] of the ! operator, scalar type. */
7578         semantic_condition(expression->value, "operand of !");
7579         expression->base.type = c_mode & _CXX ? type_bool : type_int;
7580 }
7581
7582 static void semantic_complement(unary_expression_t *expression)
7583 {
7584         type_t *const orig_type = expression->value->base.type;
7585         type_t *const type      = skip_typeref(orig_type);
7586         if (!is_type_integer(type) && (!GNU_MODE || !is_type_complex(type))) {
7587                 if (is_type_valid(type)) {
7588                         errorf(&expression->base.pos, "operand of ~ must be of integer type");
7589                 }
7590                 return;
7591         }
7592
7593         if (is_type_integer(type)) {
7594                 promote_unary_int_expr(expression, type);
7595         } else {
7596                 expression->base.type = orig_type;
7597         }
7598 }
7599
7600 static void semantic_dereference(unary_expression_t *expression)
7601 {
7602         type_t *const orig_type = expression->value->base.type;
7603         type_t *const type      = skip_typeref(orig_type);
7604         if (!is_type_pointer(type)) {
7605                 if (is_type_valid(type)) {
7606                         errorf(&expression->base.pos,
7607                                "Unary '*' needs pointer or array type, but type '%T' given", orig_type);
7608                 }
7609                 return;
7610         }
7611
7612         type_t *result_type   = type->pointer.points_to;
7613         result_type           = automatic_type_conversion(result_type);
7614         expression->base.type = result_type;
7615 }
7616
7617 /**
7618  * Record that an address is taken (expression represents an lvalue).
7619  *
7620  * @param expression       the expression
7621  * @param may_be_register  if true, the expression might be an register
7622  */
7623 static void set_address_taken(expression_t *expression, bool may_be_register)
7624 {
7625         if (expression->kind != EXPR_REFERENCE)
7626                 return;
7627
7628         entity_t *const entity = expression->reference.entity;
7629
7630         if (entity->kind != ENTITY_VARIABLE && entity->kind != ENTITY_PARAMETER)
7631                 return;
7632
7633         if (entity->declaration.storage_class == STORAGE_CLASS_REGISTER
7634                         && !may_be_register) {
7635                 position_t const *const pos = &expression->base.pos;
7636                 errorf(pos, "address of register '%N' requested", entity);
7637         }
7638
7639         entity->variable.address_taken = true;
7640 }
7641
7642 /**
7643  * Check the semantic of the address taken expression.
7644  */
7645 static void semantic_take_addr(unary_expression_t *expression)
7646 {
7647         expression_t *value = expression->value;
7648         value->base.type    = revert_automatic_type_conversion(value);
7649
7650         type_t *orig_type = value->base.type;
7651         type_t *type      = skip_typeref(orig_type);
7652         if (!is_type_valid(type))
7653                 return;
7654
7655         /* §6.5.3.2 */
7656         if (!is_lvalue(value)) {
7657                 errorf(&expression->base.pos, "'&' requires an lvalue");
7658         }
7659         if (is_bitfield(value)) {
7660                 errorf(&expression->base.pos, "'&' not allowed on bitfield");
7661         }
7662
7663         set_address_taken(value, false);
7664
7665         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
7666 }
7667
7668 #define CREATE_UNARY_EXPRESSION_PARSER(token_kind, unexpression_type, sfunc) \
7669 static expression_t *parse_##unexpression_type(void)                         \
7670 {                                                                            \
7671         expression_t *unary_expression                                           \
7672                 = allocate_expression_zero(unexpression_type);                       \
7673         eat(token_kind);                                                         \
7674         unary_expression->unary.value = parse_subexpression(PREC_UNARY);         \
7675                                                                                  \
7676         sfunc(&unary_expression->unary);                                         \
7677                                                                                  \
7678         return unary_expression;                                                 \
7679 }
7680
7681 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
7682                                semantic_unexpr_arithmetic)
7683 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
7684                                semantic_unexpr_plus)
7685 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
7686                                semantic_not)
7687 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
7688                                semantic_dereference)
7689 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
7690                                semantic_take_addr)
7691 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_COMPLEMENT,
7692                                semantic_complement)
7693 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
7694                                semantic_incdec)
7695 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
7696                                semantic_incdec)
7697
7698 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_kind, unexpression_type, \
7699                                                sfunc)                         \
7700 static expression_t *parse_##unexpression_type(expression_t *left)            \
7701 {                                                                             \
7702         expression_t *unary_expression                                            \
7703                 = allocate_expression_zero(unexpression_type);                        \
7704         eat(token_kind);                                                          \
7705         unary_expression->unary.value = left;                                     \
7706                                                                                   \
7707         sfunc(&unary_expression->unary);                                          \
7708                                                                               \
7709         return unary_expression;                                                  \
7710 }
7711
7712 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
7713                                        EXPR_UNARY_POSTFIX_INCREMENT,
7714                                        semantic_incdec)
7715 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
7716                                        EXPR_UNARY_POSTFIX_DECREMENT,
7717                                        semantic_incdec)
7718
7719 static atomic_type_kind_t semantic_arithmetic_(atomic_type_kind_t kind_left,
7720                                                atomic_type_kind_t kind_right)
7721 {
7722         /* §6.3.1.8 Usual arithmetic conversions */
7723         if (kind_left == ATOMIC_TYPE_LONG_DOUBLE
7724          || kind_right == ATOMIC_TYPE_LONG_DOUBLE) {
7725                 return ATOMIC_TYPE_LONG_DOUBLE;
7726         } else if (kind_left == ATOMIC_TYPE_DOUBLE
7727                 || kind_right == ATOMIC_TYPE_DOUBLE) {
7728             return ATOMIC_TYPE_DOUBLE;
7729         } else if (kind_left == ATOMIC_TYPE_FLOAT
7730                 || kind_right == ATOMIC_TYPE_FLOAT) {
7731                 return ATOMIC_TYPE_FLOAT;
7732         }
7733
7734         unsigned       rank_left  = get_akind_rank(kind_left);
7735         unsigned       rank_right = get_akind_rank(kind_right);
7736         unsigned const rank_int   = get_akind_rank(ATOMIC_TYPE_INT);
7737         if (rank_left < rank_int) {
7738                 kind_left = ATOMIC_TYPE_INT;
7739                 rank_left = rank_int;
7740         }
7741         if (rank_right < rank_int) {
7742                 kind_right = ATOMIC_TYPE_INT;
7743                 rank_right = rank_int;
7744         }
7745         if (kind_left == kind_right)
7746                 return kind_left;
7747
7748         bool const signed_left  = is_akind_signed(kind_left);
7749         bool const signed_right = is_akind_signed(kind_right);
7750         if (signed_left == signed_right)
7751                 return rank_left >= rank_right ? kind_left : kind_right;
7752
7753         unsigned           s_rank;
7754         unsigned           u_rank;
7755         atomic_type_kind_t s_kind;
7756         atomic_type_kind_t u_kind;
7757         if (signed_left) {
7758                 s_kind = kind_left;
7759                 s_rank = rank_left;
7760                 u_kind = kind_right;
7761                 u_rank = rank_right;
7762         } else {
7763                 s_kind = kind_right;
7764                 s_rank = rank_right;
7765                 u_kind = kind_left;
7766                 u_rank = rank_left;
7767         }
7768         if (u_rank >= s_rank)
7769                 return u_kind;
7770         if (get_atomic_type_size(s_kind) > get_atomic_type_size(u_kind))
7771                 return s_kind;
7772
7773         switch (s_kind) {
7774         case ATOMIC_TYPE_INT:      return ATOMIC_TYPE_UINT;
7775         case ATOMIC_TYPE_LONG:     return ATOMIC_TYPE_ULONG;
7776         case ATOMIC_TYPE_LONGLONG: return ATOMIC_TYPE_ULONGLONG;
7777         default: panic("invalid atomic type");
7778         }
7779 }
7780
7781 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
7782 {
7783         atomic_type_kind_t kind_left  = get_arithmetic_akind(type_left);
7784         atomic_type_kind_t kind_right = get_arithmetic_akind(type_right);
7785         atomic_type_kind_t kind_res   = semantic_arithmetic_(kind_left, kind_right);
7786
7787         if (type_left->kind == TYPE_COMPLEX || type_right->kind == TYPE_COMPLEX) {
7788                 return make_complex_type(kind_res, TYPE_QUALIFIER_NONE);
7789         }
7790         return make_atomic_type(kind_res, TYPE_QUALIFIER_NONE);
7791 }
7792
7793 /**
7794  * Check the semantic restrictions for a binary expression.
7795  */
7796 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
7797 {
7798         expression_t *const left            = expression->left;
7799         expression_t *const right           = expression->right;
7800         type_t       *const orig_type_left  = left->base.type;
7801         type_t       *const orig_type_right = right->base.type;
7802         type_t       *const type_left       = skip_typeref(orig_type_left);
7803         type_t       *const type_right      = skip_typeref(orig_type_right);
7804
7805         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
7806                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7807                         position_t const *const pos = &expression->base.pos;
7808                         errorf(pos, "operands of binary expression must have arithmetic types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7809                 }
7810                 return;
7811         }
7812
7813         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7814         expression->left      = create_implicit_cast(left, arithmetic_type);
7815         expression->right     = create_implicit_cast(right, arithmetic_type);
7816         expression->base.type = arithmetic_type;
7817 }
7818
7819 static void semantic_binexpr_integer(binary_expression_t *const expression)
7820 {
7821         expression_t *const left            = expression->left;
7822         expression_t *const right           = expression->right;
7823         type_t       *const orig_type_left  = left->base.type;
7824         type_t       *const orig_type_right = right->base.type;
7825         type_t       *const type_left       = skip_typeref(orig_type_left);
7826         type_t       *const type_right      = skip_typeref(orig_type_right);
7827
7828         if (!is_type_integer(type_left) || !is_type_integer(type_right)
7829           || is_type_complex(type_left) || is_type_complex(type_right)) {
7830                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7831                         position_t const *const pos = &expression->base.pos;
7832                         errorf(pos, "operands of binary expression must have integer types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7833                 }
7834                 return;
7835         }
7836
7837         type_t *const result_type = semantic_arithmetic(type_left, type_right);
7838         expression->left      = create_implicit_cast(left, result_type);
7839         expression->right     = create_implicit_cast(right, result_type);
7840         expression->base.type = result_type;
7841 }
7842
7843 static void warn_div_by_zero(binary_expression_t const *const expression)
7844 {
7845         if (!is_type_integer(expression->base.type))
7846                 return;
7847
7848         expression_t const *const right = expression->right;
7849         /* The type of the right operand can be different for /= */
7850         if (is_type_integer(skip_typeref(right->base.type))      &&
7851             is_constant_expression(right) >= EXPR_CLASS_CONSTANT &&
7852             !fold_constant_to_bool(right)) {
7853                 position_t const *const pos = &expression->base.pos;
7854                 warningf(WARN_DIV_BY_ZERO, pos, "division by zero");
7855         }
7856 }
7857
7858 /**
7859  * Check the semantic restrictions for a div expression.
7860  */
7861 static void semantic_div(binary_expression_t *expression)
7862 {
7863         semantic_binexpr_arithmetic(expression);
7864         warn_div_by_zero(expression);
7865 }
7866
7867 /**
7868  * Check the semantic restrictions for a mod expression.
7869  */
7870 static void semantic_mod(binary_expression_t *expression)
7871 {
7872         semantic_binexpr_integer(expression);
7873         warn_div_by_zero(expression);
7874 }
7875
7876 static void warn_addsub_in_shift(const expression_t *const expr)
7877 {
7878         if (expr->base.parenthesized)
7879                 return;
7880
7881         char op;
7882         switch (expr->kind) {
7883                 case EXPR_BINARY_ADD: op = '+'; break;
7884                 case EXPR_BINARY_SUB: op = '-'; break;
7885                 default:              return;
7886         }
7887
7888         position_t const *const pos = &expr->base.pos;
7889         warningf(WARN_PARENTHESES, pos, "suggest parentheses around '%c' inside shift", op);
7890 }
7891
7892 static bool semantic_shift(binary_expression_t *expression)
7893 {
7894         expression_t *const left            = expression->left;
7895         expression_t *const right           = expression->right;
7896         type_t       *const orig_type_left  = left->base.type;
7897         type_t       *const orig_type_right = right->base.type;
7898         type_t       *      type_left       = skip_typeref(orig_type_left);
7899         type_t       *      type_right      = skip_typeref(orig_type_right);
7900
7901         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7902                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7903                         position_t const *const pos = &expression->base.pos;
7904                         errorf(pos, "operands of shift expression must have integer types, but are '%T' and '%T'", orig_type_left, orig_type_right);
7905                 }
7906                 return false;
7907         }
7908
7909         type_left = promote_integer(type_left);
7910
7911         if (is_constant_expression(right) >= EXPR_CLASS_CONSTANT) {
7912                 position_t const *const pos   = &right->base.pos;
7913                 long              const count = fold_constant_to_int(right);
7914                 if (count < 0) {
7915                         warningf(WARN_OTHER, pos, "shift count must be non-negative");
7916                 } else if ((unsigned long)count >=
7917                                 get_atomic_type_size(type_left->atomic.akind) * 8) {
7918                         warningf(WARN_OTHER, pos, "shift count must be less than type width");
7919                 }
7920         }
7921
7922         type_right        = promote_integer(type_right);
7923         expression->right = create_implicit_cast(right, type_right);
7924
7925         return true;
7926 }
7927
7928 static void semantic_shift_op(binary_expression_t *expression)
7929 {
7930         expression_t *const left  = expression->left;
7931         expression_t *const right = expression->right;
7932
7933         if (!semantic_shift(expression))
7934                 return;
7935
7936         warn_addsub_in_shift(left);
7937         warn_addsub_in_shift(right);
7938
7939         type_t *const orig_type_left = left->base.type;
7940         type_t *      type_left      = skip_typeref(orig_type_left);
7941
7942         type_left             = promote_integer(type_left);
7943         expression->left      = create_implicit_cast(left, type_left);
7944         expression->base.type = type_left;
7945 }
7946
7947 static void semantic_add(binary_expression_t *expression)
7948 {
7949         expression_t *const left            = expression->left;
7950         expression_t *const right           = expression->right;
7951         type_t       *const orig_type_left  = left->base.type;
7952         type_t       *const orig_type_right = right->base.type;
7953         type_t       *const type_left       = skip_typeref(orig_type_left);
7954         type_t       *const type_right      = skip_typeref(orig_type_right);
7955
7956         /* §6.5.6 */
7957         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7958                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7959                 expression->left  = create_implicit_cast(left, arithmetic_type);
7960                 expression->right = create_implicit_cast(right, arithmetic_type);
7961                 expression->base.type = arithmetic_type;
7962         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7963                 check_pointer_arithmetic(&expression->base.pos, type_left,
7964                                          orig_type_left);
7965                 expression->base.type = type_left;
7966         } else if (is_type_pointer(type_right) && is_type_integer(type_left)) {
7967                 check_pointer_arithmetic(&expression->base.pos, type_right,
7968                                          orig_type_right);
7969                 expression->base.type = type_right;
7970         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7971                 errorf(&expression->base.pos,
7972                        "invalid operands to binary + ('%T', '%T')",
7973                        orig_type_left, orig_type_right);
7974         }
7975 }
7976
7977 static void semantic_sub(binary_expression_t *expression)
7978 {
7979         expression_t     *const left            = expression->left;
7980         expression_t     *const right           = expression->right;
7981         type_t           *const orig_type_left  = left->base.type;
7982         type_t           *const orig_type_right = right->base.type;
7983         type_t           *const type_left       = skip_typeref(orig_type_left);
7984         type_t           *const type_right      = skip_typeref(orig_type_right);
7985         position_t const *const pos             = &expression->base.pos;
7986
7987         /* §5.6.5 */
7988         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7989                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7990                 expression->left        = create_implicit_cast(left, arithmetic_type);
7991                 expression->right       = create_implicit_cast(right, arithmetic_type);
7992                 expression->base.type =  arithmetic_type;
7993         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7994                 check_pointer_arithmetic(&expression->base.pos, type_left,
7995                                          orig_type_left);
7996                 expression->base.type = type_left;
7997         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
7998                 type_t *const unqual_left  = get_unqualified_type(skip_typeref(type_left->pointer.points_to));
7999                 type_t *const unqual_right = get_unqualified_type(skip_typeref(type_right->pointer.points_to));
8000                 if (!types_compatible(unqual_left, unqual_right)) {
8001                         errorf(pos,
8002                                "subtracting pointers to incompatible types '%T' and '%T'",
8003                                orig_type_left, orig_type_right);
8004                 } else if (!is_type_object(unqual_left)) {
8005                         if (!is_type_void(unqual_left)) {
8006                                 errorf(pos, "subtracting pointers to non-object types '%T'",
8007                                        orig_type_left);
8008                         } else {
8009                                 warningf(WARN_OTHER, pos, "subtracting pointers to void");
8010                         }
8011                 }
8012                 expression->base.type = type_ptrdiff_t;
8013         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8014                 errorf(pos, "invalid operands of types '%T' and '%T' to binary '-'",
8015                        orig_type_left, orig_type_right);
8016         }
8017 }
8018
8019 static void warn_string_literal_address(expression_t const* expr)
8020 {
8021         while (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
8022                 expr = expr->unary.value;
8023                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
8024                         return;
8025                 expr = expr->unary.value;
8026         }
8027
8028         if (expr->kind == EXPR_STRING_LITERAL) {
8029                 position_t const *const pos = &expr->base.pos;
8030                 warningf(WARN_ADDRESS, pos, "comparison with string literal results in unspecified behaviour");
8031         }
8032 }
8033
8034 static bool maybe_negative(expression_t const *const expr)
8035 {
8036         switch (is_constant_expression(expr)) {
8037                 case EXPR_CLASS_VARIABLE:         return true;
8038                 case EXPR_CLASS_ERROR:            return false;
8039                 case EXPR_CLASS_CONSTANT:
8040                 case EXPR_CLASS_INTEGER_CONSTANT: return constant_is_negative(expr);
8041         }
8042         panic("invalid expression classification");
8043 }
8044
8045 static void warn_comparison(position_t const *const pos, expression_t const *const expr, expression_t const *const other)
8046 {
8047         warn_string_literal_address(expr);
8048
8049         expression_t const* const ref = get_reference_address(expr);
8050         if (ref != NULL && is_null_pointer_constant(other)) {
8051                 entity_t const *const ent = ref->reference.entity;
8052                 warningf(WARN_ADDRESS, pos, "the address of '%N' will never be NULL", ent);
8053         }
8054
8055         if (!expr->base.parenthesized) {
8056                 switch (expr->base.kind) {
8057                         case EXPR_BINARY_LESS:
8058                         case EXPR_BINARY_GREATER:
8059                         case EXPR_BINARY_LESSEQUAL:
8060                         case EXPR_BINARY_GREATEREQUAL:
8061                         case EXPR_BINARY_NOTEQUAL:
8062                         case EXPR_BINARY_EQUAL:
8063                                 warningf(WARN_PARENTHESES, pos, "comparisons like 'x <= y < z' do not have their mathematical meaning");
8064                                 break;
8065                         default:
8066                                 break;
8067                 }
8068         }
8069 }
8070
8071 /**
8072  * Check the semantics of comparison expressions.
8073  */
8074 static void semantic_comparison(binary_expression_t *expression,
8075                                 bool is_relational)
8076 {
8077         position_t const *const pos   = &expression->base.pos;
8078         expression_t     *const left  = expression->left;
8079         expression_t     *const right = expression->right;
8080
8081         warn_comparison(pos, left, right);
8082         warn_comparison(pos, right, left);
8083
8084         type_t *orig_type_left  = left->base.type;
8085         type_t *orig_type_right = right->base.type;
8086         type_t *type_left       = skip_typeref(orig_type_left);
8087         type_t *type_right      = skip_typeref(orig_type_right);
8088
8089         /* TODO non-arithmetic types */
8090         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8091                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8092
8093                 /* test for signed vs unsigned compares */
8094                 if (is_type_integer(arithmetic_type)) {
8095                         bool const signed_left  = is_type_signed(type_left);
8096                         bool const signed_right = is_type_signed(type_right);
8097                         if (signed_left != signed_right) {
8098                                 /* FIXME long long needs better const folding magic */
8099                                 /* TODO check whether constant value can be represented by other type */
8100                                 if ((signed_left  && maybe_negative(left)) ||
8101                                                 (signed_right && maybe_negative(right))) {
8102                                         warningf(WARN_SIGN_COMPARE, pos, "comparison between signed and unsigned");
8103                                 }
8104                         }
8105                 }
8106
8107                 expression->left      = create_implicit_cast(left, arithmetic_type);
8108                 expression->right     = create_implicit_cast(right, arithmetic_type);
8109                 expression->base.type = arithmetic_type;
8110                 if (!is_relational && is_type_float(arithmetic_type)) {
8111                         warningf(WARN_FLOAT_EQUAL, pos, "comparing floating point with == or != is unsafe");
8112                 }
8113                 /* for relational ops we need real types, not just arithmetic */
8114                 if (is_relational
8115                     && (!is_type_real(type_left) || !is_type_real(type_right))) {
8116                         type_error_incompatible("invalid operands for relational operator", pos, type_left, type_right);
8117                 }
8118         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
8119                 /* TODO check compatibility */
8120         } else if (is_type_pointer(type_left)) {
8121                 expression->right = create_implicit_cast(right, type_left);
8122         } else if (is_type_pointer(type_right)) {
8123                 expression->left = create_implicit_cast(left, type_right);
8124         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8125                 type_error_incompatible("invalid operands in comparison", pos, type_left, type_right);
8126         }
8127         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8128 }
8129
8130 static void semantic_relational(binary_expression_t *expression)
8131 {
8132         semantic_comparison(expression, true);
8133 }
8134
8135 static void semantic_equality(binary_expression_t *expression)
8136 {
8137         semantic_comparison(expression, false);
8138 }
8139
8140 /**
8141  * Checks if a compound type has constant fields.
8142  */
8143 static bool has_const_fields(const compound_type_t *type)
8144 {
8145         compound_t *compound = type->compound;
8146         entity_t   *entry    = compound->members.entities;
8147
8148         for (; entry != NULL; entry = entry->base.next) {
8149                 if (!is_declaration(entry))
8150                         continue;
8151
8152                 const type_t *decl_type = skip_typeref(entry->declaration.type);
8153                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
8154                         return true;
8155         }
8156
8157         return false;
8158 }
8159
8160 static bool is_valid_assignment_lhs(expression_t const* const left)
8161 {
8162         type_t *const orig_type_left = revert_automatic_type_conversion(left);
8163         type_t *const type_left      = skip_typeref(orig_type_left);
8164
8165         if (!is_lvalue(left)) {
8166                 errorf(&left->base.pos,
8167                        "left hand side '%E' of assignment is not an lvalue", left);
8168                 return false;
8169         }
8170
8171         if (left->kind == EXPR_REFERENCE
8172                         && left->reference.entity->kind == ENTITY_FUNCTION) {
8173                 errorf(&left->base.pos, "cannot assign to function '%E'", left);
8174                 return false;
8175         }
8176
8177         if (is_type_array(type_left)) {
8178                 errorf(&left->base.pos, "cannot assign to array '%E'", left);
8179                 return false;
8180         }
8181         if (type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
8182                 errorf(&left->base.pos,
8183                        "assignment to read-only location '%E' (type '%T')", left,
8184                        orig_type_left);
8185                 return false;
8186         }
8187         if (is_type_incomplete(type_left)) {
8188                 errorf(&left->base.pos, "left-hand side '%E' of assignment has incomplete type '%T'",
8189                        left, orig_type_left);
8190                 return false;
8191         }
8192         if (is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
8193                 errorf(&left->base.pos, "cannot assign to '%E' because compound type '%T' has read-only fields",
8194                        left, orig_type_left);
8195                 return false;
8196         }
8197
8198         return true;
8199 }
8200
8201 static void semantic_arithmetic_assign(binary_expression_t *expression)
8202 {
8203         expression_t *left            = expression->left;
8204         expression_t *right           = expression->right;
8205         type_t       *orig_type_left  = left->base.type;
8206         type_t       *orig_type_right = right->base.type;
8207
8208         if (!is_valid_assignment_lhs(left))
8209                 return;
8210
8211         type_t *type_left  = skip_typeref(orig_type_left);
8212         type_t *type_right = skip_typeref(orig_type_right);
8213
8214         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
8215                 /* TODO: improve error message */
8216                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8217                         errorf(&expression->base.pos, "operation needs arithmetic types");
8218                 }
8219                 return;
8220         }
8221
8222         /* combined instructions are tricky. We can't create an implicit cast on
8223          * the left side, because we need the uncasted form for the store.
8224          * The ast2firm pass has to know that left_type must be right_type
8225          * for the arithmetic operation and create a cast by itself */
8226         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8227         expression->right       = create_implicit_cast(right, arithmetic_type);
8228         expression->base.type   = type_left;
8229 }
8230
8231 static void semantic_divmod_assign(binary_expression_t *expression)
8232 {
8233         semantic_arithmetic_assign(expression);
8234         warn_div_by_zero(expression);
8235 }
8236
8237 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
8238 {
8239         expression_t *const left            = expression->left;
8240         expression_t *const right           = expression->right;
8241         type_t       *const orig_type_left  = left->base.type;
8242         type_t       *const orig_type_right = right->base.type;
8243         type_t       *const type_left       = skip_typeref(orig_type_left);
8244         type_t       *const type_right      = skip_typeref(orig_type_right);
8245
8246         if (!is_valid_assignment_lhs(left))
8247                 return;
8248
8249         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8250                 /* combined instructions are tricky. We can't create an implicit cast on
8251                  * the left side, because we need the uncasted form for the store.
8252                  * The ast2firm pass has to know that left_type must be right_type
8253                  * for the arithmetic operation and create a cast by itself */
8254                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
8255                 expression->right     = create_implicit_cast(right, arithmetic_type);
8256                 expression->base.type = type_left;
8257         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
8258                 check_pointer_arithmetic(&expression->base.pos, type_left,
8259                                          orig_type_left);
8260                 expression->base.type = type_left;
8261         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8262                 errorf(&expression->base.pos,
8263                        "incompatible types '%T' and '%T' in assignment",
8264                        orig_type_left, orig_type_right);
8265         }
8266 }
8267
8268 static void semantic_integer_assign(binary_expression_t *expression)
8269 {
8270         expression_t *left            = expression->left;
8271         expression_t *right           = expression->right;
8272         type_t       *orig_type_left  = left->base.type;
8273         type_t       *orig_type_right = right->base.type;
8274
8275         if (!is_valid_assignment_lhs(left))
8276                 return;
8277
8278         type_t *type_left  = skip_typeref(orig_type_left);
8279         type_t *type_right = skip_typeref(orig_type_right);
8280
8281         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
8282                 /* TODO: improve error message */
8283                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8284                         errorf(&expression->base.pos, "operation needs integer types");
8285                 }
8286                 return;
8287         }
8288
8289         /* combined instructions are tricky. We can't create an implicit cast on
8290          * the left side, because we need the uncasted form for the store.
8291          * The ast2firm pass has to know that left_type must be right_type
8292          * for the arithmetic operation and create a cast by itself */
8293         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8294         expression->right       = create_implicit_cast(right, arithmetic_type);
8295         expression->base.type   = type_left;
8296 }
8297
8298 static void semantic_shift_assign(binary_expression_t *expression)
8299 {
8300         expression_t *left           = expression->left;
8301
8302         if (!is_valid_assignment_lhs(left))
8303                 return;
8304
8305         if (!semantic_shift(expression))
8306                 return;
8307
8308         expression->base.type = skip_typeref(left->base.type);
8309 }
8310
8311 static void warn_logical_and_within_or(const expression_t *const expr)
8312 {
8313         if (expr->base.kind != EXPR_BINARY_LOGICAL_AND)
8314                 return;
8315         if (expr->base.parenthesized)
8316                 return;
8317         position_t const *const pos = &expr->base.pos;
8318         warningf(WARN_PARENTHESES, pos, "suggest parentheses around && within ||");
8319 }
8320
8321 /**
8322  * Check the semantic restrictions of a logical expression.
8323  */
8324 static void semantic_logical_op(binary_expression_t *expression)
8325 {
8326         /* §6.5.13:2  Each of the operands shall have scalar type.
8327          * §6.5.14:2  Each of the operands shall have scalar type. */
8328         semantic_condition(expression->left,   "left operand of logical operator");
8329         semantic_condition(expression->right, "right operand of logical operator");
8330         if (expression->base.kind == EXPR_BINARY_LOGICAL_OR) {
8331                 warn_logical_and_within_or(expression->left);
8332                 warn_logical_and_within_or(expression->right);
8333         }
8334         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8335 }
8336
8337 /**
8338  * Check the semantic restrictions of a binary assign expression.
8339  */
8340 static void semantic_binexpr_assign(binary_expression_t *expression)
8341 {
8342         expression_t *left           = expression->left;
8343         type_t       *orig_type_left = left->base.type;
8344
8345         if (!is_valid_assignment_lhs(left))
8346                 return;
8347
8348         assign_error_t error = semantic_assign(orig_type_left, expression->right);
8349         report_assign_error(error, orig_type_left, expression->right,
8350                             "assignment", &left->base.pos);
8351         expression->right = create_implicit_cast(expression->right, orig_type_left);
8352         expression->base.type = orig_type_left;
8353 }
8354
8355 /**
8356  * Determine if the outermost operation (or parts thereof) of the given
8357  * expression has no effect in order to generate a warning about this fact.
8358  * Therefore in some cases this only examines some of the operands of the
8359  * expression (see comments in the function and examples below).
8360  * Examples:
8361  *   f() + 23;    // warning, because + has no effect
8362  *   x || f();    // no warning, because x controls execution of f()
8363  *   x ? y : f(); // warning, because y has no effect
8364  *   (void)x;     // no warning to be able to suppress the warning
8365  * This function can NOT be used for an "expression has definitely no effect"-
8366  * analysis. */
8367 static bool expression_has_effect(const expression_t *const expr)
8368 {
8369         switch (expr->kind) {
8370                 case EXPR_ERROR:                      return true; /* do NOT warn */
8371                 case EXPR_REFERENCE:                  return false;
8372                 case EXPR_ENUM_CONSTANT:              return false;
8373                 case EXPR_LABEL_ADDRESS:              return false;
8374
8375                 /* suppress the warning for microsoft __noop operations */
8376                 case EXPR_LITERAL_MS_NOOP:            return true;
8377                 case EXPR_LITERAL_BOOLEAN:
8378                 case EXPR_LITERAL_CHARACTER:
8379                 case EXPR_LITERAL_INTEGER:
8380                 case EXPR_LITERAL_FLOATINGPOINT:
8381                 case EXPR_STRING_LITERAL:             return false;
8382
8383                 case EXPR_CALL: {
8384                         const call_expression_t *const call = &expr->call;
8385                         if (call->function->kind != EXPR_REFERENCE)
8386                                 return true;
8387
8388                         switch (call->function->reference.entity->function.btk) {
8389                                 /* FIXME: which builtins have no effect? */
8390                                 default:                      return true;
8391                         }
8392                 }
8393
8394                 /* Generate the warning if either the left or right hand side of a
8395                  * conditional expression has no effect */
8396                 case EXPR_CONDITIONAL: {
8397                         conditional_expression_t const *const cond = &expr->conditional;
8398                         expression_t             const *const t    = cond->true_expression;
8399                         return
8400                                 (t == NULL || expression_has_effect(t)) &&
8401                                 expression_has_effect(cond->false_expression);
8402                 }
8403
8404                 case EXPR_SELECT:                     return false;
8405                 case EXPR_ARRAY_ACCESS:               return false;
8406                 case EXPR_SIZEOF:                     return false;
8407                 case EXPR_CLASSIFY_TYPE:              return false;
8408                 case EXPR_ALIGNOF:                    return false;
8409
8410                 case EXPR_FUNCNAME:                   return false;
8411                 case EXPR_BUILTIN_CONSTANT_P:         return false;
8412                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P: return false;
8413                 case EXPR_OFFSETOF:                   return false;
8414                 case EXPR_VA_START:                   return true;
8415                 case EXPR_VA_ARG:                     return true;
8416                 case EXPR_VA_COPY:                    return true;
8417                 case EXPR_STATEMENT:                  return true; // TODO
8418                 case EXPR_COMPOUND_LITERAL:           return false;
8419
8420                 case EXPR_UNARY_NEGATE:               return false;
8421                 case EXPR_UNARY_PLUS:                 return false;
8422                 case EXPR_UNARY_COMPLEMENT:           return false;
8423                 case EXPR_UNARY_NOT:                  return false;
8424                 case EXPR_UNARY_DEREFERENCE:          return false;
8425                 case EXPR_UNARY_TAKE_ADDRESS:         return false;
8426                 case EXPR_UNARY_REAL:                 return false;
8427                 case EXPR_UNARY_IMAG:                 return false;
8428                 case EXPR_UNARY_POSTFIX_INCREMENT:    return true;
8429                 case EXPR_UNARY_POSTFIX_DECREMENT:    return true;
8430                 case EXPR_UNARY_PREFIX_INCREMENT:     return true;
8431                 case EXPR_UNARY_PREFIX_DECREMENT:     return true;
8432
8433                 /* Treat void casts as if they have an effect in order to being able to
8434                  * suppress the warning */
8435                 case EXPR_UNARY_CAST: {
8436                         type_t *const type = skip_typeref(expr->base.type);
8437                         return is_type_void(type);
8438                 }
8439
8440                 case EXPR_UNARY_ASSUME:               return true;
8441                 case EXPR_UNARY_DELETE:               return true;
8442                 case EXPR_UNARY_DELETE_ARRAY:         return true;
8443                 case EXPR_UNARY_THROW:                return true;
8444
8445                 case EXPR_BINARY_ADD:                 return false;
8446                 case EXPR_BINARY_SUB:                 return false;
8447                 case EXPR_BINARY_MUL:                 return false;
8448                 case EXPR_BINARY_DIV:                 return false;
8449                 case EXPR_BINARY_MOD:                 return false;
8450                 case EXPR_BINARY_EQUAL:               return false;
8451                 case EXPR_BINARY_NOTEQUAL:            return false;
8452                 case EXPR_BINARY_LESS:                return false;
8453                 case EXPR_BINARY_LESSEQUAL:           return false;
8454                 case EXPR_BINARY_GREATER:             return false;
8455                 case EXPR_BINARY_GREATEREQUAL:        return false;
8456                 case EXPR_BINARY_BITWISE_AND:         return false;
8457                 case EXPR_BINARY_BITWISE_OR:          return false;
8458                 case EXPR_BINARY_BITWISE_XOR:         return false;
8459                 case EXPR_BINARY_SHIFTLEFT:           return false;
8460                 case EXPR_BINARY_SHIFTRIGHT:          return false;
8461                 case EXPR_BINARY_ASSIGN:              return true;
8462                 case EXPR_BINARY_MUL_ASSIGN:          return true;
8463                 case EXPR_BINARY_DIV_ASSIGN:          return true;
8464                 case EXPR_BINARY_MOD_ASSIGN:          return true;
8465                 case EXPR_BINARY_ADD_ASSIGN:          return true;
8466                 case EXPR_BINARY_SUB_ASSIGN:          return true;
8467                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:    return true;
8468                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:   return true;
8469                 case EXPR_BINARY_BITWISE_AND_ASSIGN:  return true;
8470                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:  return true;
8471                 case EXPR_BINARY_BITWISE_OR_ASSIGN:   return true;
8472
8473                 /* Only examine the right hand side of && and ||, because the left hand
8474                  * side already has the effect of controlling the execution of the right
8475                  * hand side */
8476                 case EXPR_BINARY_LOGICAL_AND:
8477                 case EXPR_BINARY_LOGICAL_OR:
8478                 /* Only examine the right hand side of a comma expression, because the left
8479                  * hand side has a separate warning */
8480                 case EXPR_BINARY_COMMA:
8481                         return expression_has_effect(expr->binary.right);
8482
8483                 case EXPR_BINARY_ISGREATER:           return false;
8484                 case EXPR_BINARY_ISGREATEREQUAL:      return false;
8485                 case EXPR_BINARY_ISLESS:              return false;
8486                 case EXPR_BINARY_ISLESSEQUAL:         return false;
8487                 case EXPR_BINARY_ISLESSGREATER:       return false;
8488                 case EXPR_BINARY_ISUNORDERED:         return false;
8489         }
8490
8491         internal_errorf(HERE, "unexpected expression");
8492 }
8493
8494 static void semantic_comma(binary_expression_t *expression)
8495 {
8496         const expression_t *const left = expression->left;
8497         if (!expression_has_effect(left)) {
8498                 position_t const *const pos = &left->base.pos;
8499                 warningf(WARN_UNUSED_VALUE, pos, "left-hand operand of comma expression has no effect");
8500         }
8501         expression->base.type = expression->right->base.type;
8502 }
8503
8504 /**
8505  * @param prec_r precedence of the right operand
8506  */
8507 #define CREATE_BINEXPR_PARSER(token_kind, binexpression_type, prec_r, sfunc) \
8508 static expression_t *parse_##binexpression_type(expression_t *left)          \
8509 {                                                                            \
8510         expression_t *binexpr = allocate_expression_zero(binexpression_type);    \
8511         binexpr->binary.left  = left;                                            \
8512         eat(token_kind);                                                         \
8513                                                                              \
8514         expression_t *right = parse_subexpression(prec_r);                       \
8515                                                                              \
8516         binexpr->binary.right = right;                                           \
8517         sfunc(&binexpr->binary);                                                 \
8518                                                                              \
8519         return binexpr;                                                          \
8520 }
8521
8522 CREATE_BINEXPR_PARSER('*',                    EXPR_BINARY_MUL,                PREC_CAST,           semantic_binexpr_arithmetic)
8523 CREATE_BINEXPR_PARSER('/',                    EXPR_BINARY_DIV,                PREC_CAST,           semantic_div)
8524 CREATE_BINEXPR_PARSER('%',                    EXPR_BINARY_MOD,                PREC_CAST,           semantic_mod)
8525 CREATE_BINEXPR_PARSER('+',                    EXPR_BINARY_ADD,                PREC_MULTIPLICATIVE, semantic_add)
8526 CREATE_BINEXPR_PARSER('-',                    EXPR_BINARY_SUB,                PREC_MULTIPLICATIVE, semantic_sub)
8527 CREATE_BINEXPR_PARSER(T_LESSLESS,             EXPR_BINARY_SHIFTLEFT,          PREC_ADDITIVE,       semantic_shift_op)
8528 CREATE_BINEXPR_PARSER(T_GREATERGREATER,       EXPR_BINARY_SHIFTRIGHT,         PREC_ADDITIVE,       semantic_shift_op)
8529 CREATE_BINEXPR_PARSER('<',                    EXPR_BINARY_LESS,               PREC_SHIFT,          semantic_relational)
8530 CREATE_BINEXPR_PARSER('>',                    EXPR_BINARY_GREATER,            PREC_SHIFT,          semantic_relational)
8531 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,          PREC_SHIFT,          semantic_relational)
8532 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,       PREC_SHIFT,          semantic_relational)
8533 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,           PREC_RELATIONAL,     semantic_equality)
8534 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,              PREC_RELATIONAL,     semantic_equality)
8535 CREATE_BINEXPR_PARSER('&',                    EXPR_BINARY_BITWISE_AND,        PREC_EQUALITY,       semantic_binexpr_integer)
8536 CREATE_BINEXPR_PARSER('^',                    EXPR_BINARY_BITWISE_XOR,        PREC_AND,            semantic_binexpr_integer)
8537 CREATE_BINEXPR_PARSER('|',                    EXPR_BINARY_BITWISE_OR,         PREC_XOR,            semantic_binexpr_integer)
8538 CREATE_BINEXPR_PARSER(T_ANDAND,               EXPR_BINARY_LOGICAL_AND,        PREC_OR,             semantic_logical_op)
8539 CREATE_BINEXPR_PARSER(T_PIPEPIPE,             EXPR_BINARY_LOGICAL_OR,         PREC_LOGICAL_AND,    semantic_logical_op)
8540 CREATE_BINEXPR_PARSER('=',                    EXPR_BINARY_ASSIGN,             PREC_ASSIGNMENT,     semantic_binexpr_assign)
8541 CREATE_BINEXPR_PARSER(T_PLUSEQUAL,            EXPR_BINARY_ADD_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8542 CREATE_BINEXPR_PARSER(T_MINUSEQUAL,           EXPR_BINARY_SUB_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8543 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL,        EXPR_BINARY_MUL_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_assign)
8544 CREATE_BINEXPR_PARSER(T_SLASHEQUAL,           EXPR_BINARY_DIV_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8545 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL,         EXPR_BINARY_MOD_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8546 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL,        EXPR_BINARY_SHIFTLEFT_ASSIGN,   PREC_ASSIGNMENT,     semantic_shift_assign)
8547 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL,  EXPR_BINARY_SHIFTRIGHT_ASSIGN,  PREC_ASSIGNMENT,     semantic_shift_assign)
8548 CREATE_BINEXPR_PARSER(T_ANDEQUAL,             EXPR_BINARY_BITWISE_AND_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8549 CREATE_BINEXPR_PARSER(T_PIPEEQUAL,            EXPR_BINARY_BITWISE_OR_ASSIGN,  PREC_ASSIGNMENT,     semantic_integer_assign)
8550 CREATE_BINEXPR_PARSER(T_CARETEQUAL,           EXPR_BINARY_BITWISE_XOR_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8551 CREATE_BINEXPR_PARSER(',',                    EXPR_BINARY_COMMA,              PREC_ASSIGNMENT,     semantic_comma)
8552
8553
8554 static expression_t *parse_subexpression(precedence_t precedence)
8555 {
8556         expression_parser_function_t *parser
8557                 = &expression_parsers[token.kind];
8558         expression_t                 *left;
8559
8560         if (parser->parser != NULL) {
8561                 left = parser->parser();
8562         } else {
8563                 left = parse_primary_expression();
8564         }
8565         assert(left != NULL);
8566
8567         while (true) {
8568                 parser = &expression_parsers[token.kind];
8569                 if (parser->infix_parser == NULL)
8570                         break;
8571                 if (parser->infix_precedence < precedence)
8572                         break;
8573
8574                 left = parser->infix_parser(left);
8575
8576                 assert(left != NULL);
8577         }
8578
8579         return left;
8580 }
8581
8582 /**
8583  * Parse an expression.
8584  */
8585 static expression_t *parse_expression(void)
8586 {
8587         return parse_subexpression(PREC_EXPRESSION);
8588 }
8589
8590 /**
8591  * Register a parser for a prefix-like operator.
8592  *
8593  * @param parser      the parser function
8594  * @param token_kind  the token type of the prefix token
8595  */
8596 static void register_expression_parser(parse_expression_function parser,
8597                                        int token_kind)
8598 {
8599         expression_parser_function_t *entry = &expression_parsers[token_kind];
8600
8601         assert(!entry->parser);
8602         entry->parser = parser;
8603 }
8604
8605 /**
8606  * Register a parser for an infix operator with given precedence.
8607  *
8608  * @param parser      the parser function
8609  * @param token_kind  the token type of the infix operator
8610  * @param precedence  the precedence of the operator
8611  */
8612 static void register_infix_parser(parse_expression_infix_function parser,
8613                                   int token_kind, precedence_t precedence)
8614 {
8615         expression_parser_function_t *entry = &expression_parsers[token_kind];
8616
8617         assert(!entry->infix_parser);
8618         entry->infix_parser     = parser;
8619         entry->infix_precedence = precedence;
8620 }
8621
8622 /**
8623  * Initialize the expression parsers.
8624  */
8625 static void init_expression_parsers(void)
8626 {
8627         memset(&expression_parsers, 0, sizeof(expression_parsers));
8628
8629         register_infix_parser(parse_array_expression,               '[',                    PREC_POSTFIX);
8630         register_infix_parser(parse_call_expression,                '(',                    PREC_POSTFIX);
8631         register_infix_parser(parse_select_expression,              '.',                    PREC_POSTFIX);
8632         register_infix_parser(parse_select_expression,              T_MINUSGREATER,         PREC_POSTFIX);
8633         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,   T_PLUSPLUS,             PREC_POSTFIX);
8634         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,   T_MINUSMINUS,           PREC_POSTFIX);
8635         register_infix_parser(parse_EXPR_BINARY_MUL,                '*',                    PREC_MULTIPLICATIVE);
8636         register_infix_parser(parse_EXPR_BINARY_DIV,                '/',                    PREC_MULTIPLICATIVE);
8637         register_infix_parser(parse_EXPR_BINARY_MOD,                '%',                    PREC_MULTIPLICATIVE);
8638         register_infix_parser(parse_EXPR_BINARY_ADD,                '+',                    PREC_ADDITIVE);
8639         register_infix_parser(parse_EXPR_BINARY_SUB,                '-',                    PREC_ADDITIVE);
8640         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,          T_LESSLESS,             PREC_SHIFT);
8641         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,         T_GREATERGREATER,       PREC_SHIFT);
8642         register_infix_parser(parse_EXPR_BINARY_LESS,               '<',                    PREC_RELATIONAL);
8643         register_infix_parser(parse_EXPR_BINARY_GREATER,            '>',                    PREC_RELATIONAL);
8644         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,          T_LESSEQUAL,            PREC_RELATIONAL);
8645         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL,       T_GREATEREQUAL,         PREC_RELATIONAL);
8646         register_infix_parser(parse_EXPR_BINARY_EQUAL,              T_EQUALEQUAL,           PREC_EQUALITY);
8647         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,           T_EXCLAMATIONMARKEQUAL, PREC_EQUALITY);
8648         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,        '&',                    PREC_AND);
8649         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,        '^',                    PREC_XOR);
8650         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,         '|',                    PREC_OR);
8651         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,        T_ANDAND,               PREC_LOGICAL_AND);
8652         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,         T_PIPEPIPE,             PREC_LOGICAL_OR);
8653         register_infix_parser(parse_conditional_expression,         '?',                    PREC_CONDITIONAL);
8654         register_infix_parser(parse_EXPR_BINARY_ASSIGN,             '=',                    PREC_ASSIGNMENT);
8655         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,         T_PLUSEQUAL,            PREC_ASSIGNMENT);
8656         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,         T_MINUSEQUAL,           PREC_ASSIGNMENT);
8657         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,         T_ASTERISKEQUAL,        PREC_ASSIGNMENT);
8658         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,         T_SLASHEQUAL,           PREC_ASSIGNMENT);
8659         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,         T_PERCENTEQUAL,         PREC_ASSIGNMENT);
8660         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,   T_LESSLESSEQUAL,        PREC_ASSIGNMENT);
8661         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,  T_GREATERGREATEREQUAL,  PREC_ASSIGNMENT);
8662         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN, T_ANDEQUAL,             PREC_ASSIGNMENT);
8663         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,  T_PIPEEQUAL,            PREC_ASSIGNMENT);
8664         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN, T_CARETEQUAL,           PREC_ASSIGNMENT);
8665         register_infix_parser(parse_EXPR_BINARY_COMMA,              ',',                    PREC_EXPRESSION);
8666
8667         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-');
8668         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+');
8669         register_expression_parser(parse_EXPR_UNARY_NOT,              '!');
8670         register_expression_parser(parse_EXPR_UNARY_COMPLEMENT,       '~');
8671         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*');
8672         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&');
8673         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT, T_PLUSPLUS);
8674         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT, T_MINUSMINUS);
8675         register_expression_parser(parse_sizeof,                      T_sizeof);
8676         register_expression_parser(parse_alignof,                     T__Alignof);
8677         register_expression_parser(parse_extension,                   T___extension__);
8678         register_expression_parser(parse_builtin_classify_type,       T___builtin_classify_type);
8679         register_expression_parser(parse_delete,                      T_delete);
8680         register_expression_parser(parse_throw,                       T_throw);
8681 }
8682
8683 /**
8684  * Parse a asm statement arguments specification.
8685  */
8686 static void parse_asm_arguments(asm_argument_t **anchor, bool const is_out)
8687 {
8688         if (token.kind == T_STRING_LITERAL || token.kind == '[') {
8689                 add_anchor_token(',');
8690                 do {
8691                         asm_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
8692
8693                         add_anchor_token(')');
8694                         add_anchor_token('(');
8695                         add_anchor_token(T_STRING_LITERAL);
8696
8697                         if (accept('[')) {
8698                                 add_anchor_token(']');
8699                                 argument->symbol = expect_identifier("while parsing asm argument", NULL);
8700                                 rem_anchor_token(']');
8701                                 expect(']');
8702                         }
8703
8704                         rem_anchor_token(T_STRING_LITERAL);
8705                         argument->constraints = parse_string_literals("asm argument");
8706                         rem_anchor_token('(');
8707                         expect('(');
8708                         expression_t *expression = parse_expression();
8709                         if (is_out) {
8710                                 /* Ugly GCC stuff: Allow lvalue casts.  Skip casts, when they do not
8711                                  * change size or type representation (e.g. int -> long is ok, but
8712                                  * int -> float is not) */
8713                                 if (expression->kind == EXPR_UNARY_CAST) {
8714                                         type_t      *const type = expression->base.type;
8715                                         type_kind_t  const kind = type->kind;
8716                                         if (kind == TYPE_ATOMIC || kind == TYPE_POINTER) {
8717                                                 unsigned flags;
8718                                                 unsigned size;
8719                                                 if (kind == TYPE_ATOMIC) {
8720                                                         atomic_type_kind_t const akind = type->atomic.akind;
8721                                                         flags = get_atomic_type_flags(akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8722                                                         size  = get_atomic_type_size(akind);
8723                                                 } else {
8724                                                         flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8725                                                         size  = get_type_size(type_void_ptr);
8726                                                 }
8727
8728                                                 do {
8729                                                         expression_t *const value      = expression->unary.value;
8730                                                         type_t       *const value_type = value->base.type;
8731                                                         type_kind_t   const value_kind = value_type->kind;
8732
8733                                                         unsigned value_flags;
8734                                                         unsigned value_size;
8735                                                         if (value_kind == TYPE_ATOMIC) {
8736                                                                 atomic_type_kind_t const value_akind = value_type->atomic.akind;
8737                                                                 value_flags = get_atomic_type_flags(value_akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8738                                                                 value_size  = get_atomic_type_size(value_akind);
8739                                                         } else if (value_kind == TYPE_POINTER) {
8740                                                                 value_flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8741                                                                 value_size  = get_type_size(type_void_ptr);
8742                                                         } else {
8743                                                                 break;
8744                                                         }
8745
8746                                                         if (value_flags != flags || value_size != size)
8747                                                                 break;
8748
8749                                                         expression = value;
8750                                                 } while (expression->kind == EXPR_UNARY_CAST);
8751                                         }
8752                                 }
8753
8754                                 if (!is_lvalue(expression))
8755                                         errorf(&expression->base.pos,
8756                                                "asm output argument is not an lvalue");
8757
8758                                 if (argument->constraints.begin[0] == '=')
8759                                         determine_lhs_ent(expression, NULL);
8760                                 else
8761                                         mark_vars_read(expression, NULL);
8762                         } else {
8763                                 mark_vars_read(expression, NULL);
8764                         }
8765                         argument->expression = expression;
8766                         rem_anchor_token(')');
8767                         expect(')');
8768
8769                         set_address_taken(expression, true);
8770
8771                         *anchor = argument;
8772                         anchor  = &argument->next;
8773                 } while (accept(','));
8774                 rem_anchor_token(',');
8775         }
8776 }
8777
8778 /**
8779  * Parse a asm statement clobber specification.
8780  */
8781 static void parse_asm_clobbers(asm_clobber_t **anchor)
8782 {
8783         if (token.kind == T_STRING_LITERAL) {
8784                 add_anchor_token(',');
8785                 do {
8786                         asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
8787                         clobber->clobber       = parse_string_literals(NULL);
8788
8789                         *anchor = clobber;
8790                         anchor  = &clobber->next;
8791                 } while (accept(','));
8792                 rem_anchor_token(',');
8793         }
8794 }
8795
8796 static void parse_asm_labels(asm_label_t **anchor)
8797 {
8798         if (token.kind == T_IDENTIFIER) {
8799                 add_anchor_token(',');
8800                 do {
8801                         label_t *const label = get_label("while parsing 'asm goto' labels");
8802                         if (label) {
8803                                 asm_label_t *const asm_label = allocate_ast_zero(sizeof(*asm_label));
8804                                 asm_label->label = label;
8805
8806                                 *anchor = asm_label;
8807                                 anchor  = &asm_label->next;
8808                         }
8809                 } while (accept(','));
8810                 rem_anchor_token(',');
8811         }
8812 }
8813
8814 /**
8815  * Parse an asm statement.
8816  */
8817 static statement_t *parse_asm_statement(void)
8818 {
8819         statement_t     *statement     = allocate_statement_zero(STATEMENT_ASM);
8820         asm_statement_t *asm_statement = &statement->asms;
8821
8822         eat(T_asm);
8823         add_anchor_token(')');
8824         add_anchor_token(':');
8825         add_anchor_token(T_STRING_LITERAL);
8826
8827         if (accept(T_volatile))
8828                 asm_statement->is_volatile = true;
8829
8830         bool const asm_goto = accept(T_goto);
8831
8832         expect('(');
8833         rem_anchor_token(T_STRING_LITERAL);
8834         asm_statement->asm_text = parse_string_literals("asm statement");
8835
8836         if (accept(':')) parse_asm_arguments(&asm_statement->outputs, true);
8837         if (accept(':')) parse_asm_arguments(&asm_statement->inputs, false);
8838         if (accept(':')) parse_asm_clobbers( &asm_statement->clobbers);
8839
8840         rem_anchor_token(':');
8841         if (accept(':')) {
8842                 if (!asm_goto)
8843                         warningf(WARN_OTHER, &statement->base.pos, "assembler statement with labels should be 'asm goto'");
8844                 parse_asm_labels(&asm_statement->labels);
8845                 if (asm_statement->labels)
8846                         errorf(&statement->base.pos, "'asm goto' not supported");
8847         } else {
8848                 if (asm_goto)
8849                         warningf(WARN_OTHER, &statement->base.pos, "'asm goto' without labels");
8850         }
8851
8852         rem_anchor_token(')');
8853         expect(')');
8854         expect(';');
8855
8856         if (asm_statement->outputs == NULL) {
8857                 /* GCC: An 'asm' instruction without any output operands will be treated
8858                  * identically to a volatile 'asm' instruction. */
8859                 asm_statement->is_volatile = true;
8860         }
8861
8862         return statement;
8863 }
8864
8865 static statement_t *parse_label_inner_statement(statement_t const *const label, char const *const label_kind)
8866 {
8867         statement_t *inner_stmt;
8868         switch (token.kind) {
8869                 case '}':
8870                         errorf(&label->base.pos, "%s at end of compound statement", label_kind);
8871                         inner_stmt = create_error_statement();
8872                         break;
8873
8874                 case ';':
8875                         if (label->kind == STATEMENT_LABEL) {
8876                                 /* Eat an empty statement here, to avoid the warning about an empty
8877                                  * statement after a label.  label:; is commonly used to have a label
8878                                  * before a closing brace. */
8879                                 inner_stmt = create_empty_statement();
8880                                 eat(';');
8881                                 break;
8882                         }
8883                         /* FALLTHROUGH */
8884
8885                 default:
8886                         inner_stmt = parse_statement();
8887                         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
8888                         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
8889                         if (inner_stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
8890                                 errorf(&inner_stmt->base.pos, "declaration after %s", label_kind);
8891                         }
8892                         break;
8893         }
8894         return inner_stmt;
8895 }
8896
8897 /**
8898  * Parse a case statement.
8899  */
8900 static statement_t *parse_case_statement(void)
8901 {
8902         statement_t *const statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8903         position_t  *const pos       = &statement->base.pos;
8904
8905         eat(T_case);
8906         add_anchor_token(':');
8907
8908         expression_t *expression = parse_expression();
8909         type_t *expression_type = expression->base.type;
8910         type_t *skipped         = skip_typeref(expression_type);
8911         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8912                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8913                        expression, expression_type);
8914         }
8915
8916         type_t *type = expression_type;
8917         if (current_switch != NULL) {
8918                 type_t *switch_type = current_switch->expression->base.type;
8919                 if (is_type_valid(skip_typeref(switch_type))) {
8920                         expression = create_implicit_cast(expression, switch_type);
8921                 }
8922         }
8923
8924         statement->case_label.expression = expression;
8925         expression_classification_t const expr_class = is_constant_expression(expression);
8926         if (expr_class < EXPR_CLASS_CONSTANT) {
8927                 if (expr_class != EXPR_CLASS_ERROR) {
8928                         errorf(pos, "case label does not reduce to an integer constant");
8929                 }
8930                 statement->case_label.is_bad = true;
8931         } else {
8932                 ir_tarval *val = fold_constant_to_tarval(expression);
8933                 statement->case_label.first_case = val;
8934                 statement->case_label.last_case  = val;
8935         }
8936
8937         if (GNU_MODE) {
8938                 if (accept(T_DOTDOTDOT)) {
8939                         expression_t *end_range = parse_expression();
8940                         expression_type = expression->base.type;
8941                         skipped         = skip_typeref(expression_type);
8942                         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8943                                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8944                                            expression, expression_type);
8945                         }
8946
8947                         end_range = create_implicit_cast(end_range, type);
8948                         statement->case_label.end_range = end_range;
8949                         expression_classification_t const end_class = is_constant_expression(end_range);
8950                         if (end_class < EXPR_CLASS_CONSTANT) {
8951                                 if (end_class != EXPR_CLASS_ERROR) {
8952                                         errorf(pos, "case range does not reduce to an integer constant");
8953                                 }
8954                                 statement->case_label.is_bad = true;
8955                         } else {
8956                                 ir_tarval *val = fold_constant_to_tarval(end_range);
8957                                 statement->case_label.last_case = val;
8958
8959                                 if (tarval_cmp(val, statement->case_label.first_case)
8960                                     == ir_relation_less) {
8961                                         statement->case_label.is_empty_range = true;
8962                                         warningf(WARN_OTHER, pos, "empty range specified");
8963                                 }
8964                         }
8965                 }
8966         }
8967
8968         PUSH_PARENT(statement);
8969
8970         rem_anchor_token(':');
8971         expect(':');
8972
8973         if (current_switch != NULL) {
8974                 if (! statement->case_label.is_bad) {
8975                         /* Check for duplicate case values */
8976                         case_label_statement_t *c = &statement->case_label;
8977                         for (case_label_statement_t *l = current_switch->first_case; l != NULL; l = l->next) {
8978                                 if (l->is_bad || l->is_empty_range || l->expression == NULL)
8979                                         continue;
8980
8981                                 if (c->last_case < l->first_case || c->first_case > l->last_case)
8982                                         continue;
8983
8984                                 errorf(pos, "duplicate case value (previously used %P)",
8985                                        &l->base.pos);
8986                                 break;
8987                         }
8988                 }
8989                 /* link all cases into the switch statement */
8990                 if (current_switch->last_case == NULL) {
8991                         current_switch->first_case      = &statement->case_label;
8992                 } else {
8993                         current_switch->last_case->next = &statement->case_label;
8994                 }
8995                 current_switch->last_case = &statement->case_label;
8996         } else {
8997                 errorf(pos, "case label not within a switch statement");
8998         }
8999
9000         statement->case_label.statement = parse_label_inner_statement(statement, "case label");
9001
9002         POP_PARENT();
9003         return statement;
9004 }
9005
9006 /**
9007  * Parse a default statement.
9008  */
9009 static statement_t *parse_default_statement(void)
9010 {
9011         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
9012
9013         eat(T_default);
9014
9015         PUSH_PARENT(statement);
9016
9017         expect(':');
9018
9019         if (current_switch != NULL) {
9020                 const case_label_statement_t *def_label = current_switch->default_label;
9021                 if (def_label != NULL) {
9022                         errorf(&statement->base.pos, "multiple default labels in one switch (previous declared %P)", &def_label->base.pos);
9023                 } else {
9024                         current_switch->default_label = &statement->case_label;
9025
9026                         /* link all cases into the switch statement */
9027                         if (current_switch->last_case == NULL) {
9028                                 current_switch->first_case      = &statement->case_label;
9029                         } else {
9030                                 current_switch->last_case->next = &statement->case_label;
9031                         }
9032                         current_switch->last_case = &statement->case_label;
9033                 }
9034         } else {
9035                 errorf(&statement->base.pos,
9036                        "'default' label not within a switch statement");
9037         }
9038
9039         statement->case_label.statement = parse_label_inner_statement(statement, "default label");
9040
9041         POP_PARENT();
9042         return statement;
9043 }
9044
9045 /**
9046  * Parse a label statement.
9047  */
9048 static statement_t *parse_label_statement(void)
9049 {
9050         statement_t *const statement = allocate_statement_zero(STATEMENT_LABEL);
9051         label_t     *const label     = get_label(NULL /* Cannot fail, token is T_IDENTIFIER. */);
9052         statement->label.label = label;
9053
9054         PUSH_PARENT(statement);
9055
9056         /* if statement is already set then the label is defined twice,
9057          * otherwise it was just mentioned in a goto/local label declaration so far
9058          */
9059         position_t const* const pos = &statement->base.pos;
9060         if (label->statement != NULL) {
9061                 errorf(pos, "duplicate '%N' (declared %P)", (entity_t const*)label, &label->base.pos);
9062         } else {
9063                 label->base.pos  = *pos;
9064                 label->statement = statement;
9065                 label->n_users  += 1;
9066         }
9067
9068         eat(':');
9069
9070         if (token.kind == T___attribute__ && !(c_mode & _CXX)) {
9071                 parse_attributes(NULL); // TODO process attributes
9072         }
9073
9074         statement->label.statement = parse_label_inner_statement(statement, "label");
9075
9076         /* remember the labels in a list for later checking */
9077         *label_anchor = &statement->label;
9078         label_anchor  = &statement->label.next;
9079
9080         POP_PARENT();
9081         return statement;
9082 }
9083
9084 static statement_t *parse_inner_statement(void)
9085 {
9086         statement_t *const stmt = parse_statement();
9087         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
9088         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
9089         if (stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
9090                 errorf(&stmt->base.pos, "declaration as inner statement, use {}");
9091         }
9092         return stmt;
9093 }
9094
9095 /**
9096  * Parse an expression in parentheses and mark its variables as read.
9097  */
9098 static expression_t *parse_condition(void)
9099 {
9100         add_anchor_token(')');
9101         expect('(');
9102         expression_t *const expr = parse_expression();
9103         mark_vars_read(expr, NULL);
9104         rem_anchor_token(')');
9105         expect(')');
9106         return expr;
9107 }
9108
9109 /**
9110  * Parse an if statement.
9111  */
9112 static statement_t *parse_if(void)
9113 {
9114         statement_t *statement = allocate_statement_zero(STATEMENT_IF);
9115
9116         eat(T_if);
9117
9118         PUSH_PARENT(statement);
9119         PUSH_SCOPE_STATEMENT(&statement->ifs.scope);
9120
9121         add_anchor_token(T_else);
9122
9123         expression_t *const expr = parse_condition();
9124         statement->ifs.condition = expr;
9125         /* §6.8.4.1:1  The controlling expression of an if statement shall have
9126          *             scalar type. */
9127         semantic_condition(expr, "condition of 'if'-statment");
9128
9129         statement_t *const true_stmt = parse_inner_statement();
9130         statement->ifs.true_statement = true_stmt;
9131         rem_anchor_token(T_else);
9132
9133         if (true_stmt->kind == STATEMENT_EMPTY) {
9134                 warningf(WARN_EMPTY_BODY, HERE,
9135                         "suggest braces around empty body in an ‘if’ statement");
9136         }
9137
9138         if (accept(T_else)) {
9139                 statement->ifs.false_statement = parse_inner_statement();
9140
9141                 if (statement->ifs.false_statement->kind == STATEMENT_EMPTY) {
9142                         warningf(WARN_EMPTY_BODY, HERE,
9143                                         "suggest braces around empty body in an ‘if’ statement");
9144                 }
9145         } else if (true_stmt->kind == STATEMENT_IF &&
9146                         true_stmt->ifs.false_statement != NULL) {
9147                 position_t const *const pos = &true_stmt->base.pos;
9148                 warningf(WARN_PARENTHESES, pos, "suggest explicit braces to avoid ambiguous 'else'");
9149         }
9150
9151         POP_SCOPE();
9152         POP_PARENT();
9153         return statement;
9154 }
9155
9156 /**
9157  * Check that all enums are handled in a switch.
9158  *
9159  * @param statement  the switch statement to check
9160  */
9161 static void check_enum_cases(const switch_statement_t *statement)
9162 {
9163         if (!is_warn_on(WARN_SWITCH_ENUM))
9164                 return;
9165         type_t *type = skip_typeref(statement->expression->base.type);
9166         if (! is_type_enum(type))
9167                 return;
9168         enum_type_t *enumt = &type->enumt;
9169
9170         /* if we have a default, no warnings */
9171         if (statement->default_label != NULL)
9172                 return;
9173
9174         determine_enum_values(enumt);
9175
9176         /* FIXME: calculation of value should be done while parsing */
9177         /* TODO: quadratic algorithm here. Change to an n log n one */
9178         const entity_t *entry = enumt->enume->base.next;
9179         for (; entry != NULL && entry->kind == ENTITY_ENUM_VALUE;
9180              entry = entry->base.next) {
9181                 ir_tarval *value = entry->enum_value.tv;
9182                 bool       found = false;
9183                 for (const case_label_statement_t *l = statement->first_case; l != NULL;
9184                      l = l->next) {
9185                         if (l->expression == NULL)
9186                                 continue;
9187                         if (l->first_case == l->last_case && l->first_case != value)
9188                                 continue;
9189                         if ((tarval_cmp(l->first_case, value) & ir_relation_less_equal)
9190                          && (tarval_cmp(value, l->last_case) & ir_relation_less_equal)) {
9191                                 found = true;
9192                                 break;
9193                         }
9194                 }
9195                 if (!found) {
9196                         position_t const *const pos = &statement->base.pos;
9197                         warningf(WARN_SWITCH_ENUM, pos, "'%N' not handled in switch", entry);
9198                 }
9199         }
9200 }
9201
9202 /**
9203  * Parse a switch statement.
9204  */
9205 static statement_t *parse_switch(void)
9206 {
9207         statement_t *statement = allocate_statement_zero(STATEMENT_SWITCH);
9208
9209         eat(T_switch);
9210
9211         PUSH_PARENT(statement);
9212         PUSH_SCOPE_STATEMENT(&statement->switchs.scope);
9213
9214         expression_t *const expr = parse_condition();
9215         type_t       *      type = skip_typeref(expr->base.type);
9216         if (is_type_integer(type)) {
9217                 type = promote_integer(type);
9218                 if (get_akind_rank(get_arithmetic_akind(type)) >= get_akind_rank(ATOMIC_TYPE_LONG)) {
9219                         warningf(WARN_TRADITIONAL, &expr->base.pos,
9220                                  "'%T' switch expression not converted to '%T' in ISO C",
9221                                  type, type_int);
9222                 }
9223         } else if (is_type_valid(type)) {
9224                 errorf(&expr->base.pos, "switch quantity is not an integer, but '%T'",
9225                        type);
9226                 type = type_error_type;
9227         }
9228         statement->switchs.expression = create_implicit_cast(expr, type);
9229
9230         switch_statement_t *rem = current_switch;
9231         current_switch          = &statement->switchs;
9232         statement->switchs.body = parse_inner_statement();
9233         current_switch          = rem;
9234
9235         if (statement->switchs.default_label == NULL) {
9236                 warningf(WARN_SWITCH_DEFAULT, &statement->base.pos, "switch has no default case");
9237         }
9238         check_enum_cases(&statement->switchs);
9239
9240         POP_SCOPE();
9241         POP_PARENT();
9242         return statement;
9243 }
9244
9245 static statement_t *parse_loop_body(statement_t *const loop)
9246 {
9247         statement_t *const rem = current_loop;
9248         current_loop = loop;
9249
9250         statement_t *const body = parse_inner_statement();
9251
9252         current_loop = rem;
9253         return body;
9254 }
9255
9256 /**
9257  * Parse a while statement.
9258  */
9259 static statement_t *parse_while(void)
9260 {
9261         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9262
9263         eat(T_while);
9264
9265         PUSH_PARENT(statement);
9266         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9267
9268         expression_t *const cond = parse_condition();
9269         statement->fors.condition = cond;
9270         /* §6.8.5:2    The controlling expression of an iteration statement shall
9271          *             have scalar type. */
9272         semantic_condition(cond, "condition of 'while'-statement");
9273
9274         statement->fors.body = parse_loop_body(statement);
9275
9276         POP_SCOPE();
9277         POP_PARENT();
9278         return statement;
9279 }
9280
9281 /**
9282  * Parse a do statement.
9283  */
9284 static statement_t *parse_do(void)
9285 {
9286         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
9287
9288         eat(T_do);
9289
9290         PUSH_PARENT(statement);
9291         PUSH_SCOPE_STATEMENT(&statement->do_while.scope);
9292
9293         add_anchor_token(T_while);
9294         statement->do_while.body = parse_loop_body(statement);
9295         rem_anchor_token(T_while);
9296
9297         expect(T_while);
9298         expression_t *const cond = parse_condition();
9299         statement->do_while.condition = cond;
9300         /* §6.8.5:2    The controlling expression of an iteration statement shall
9301          *             have scalar type. */
9302         semantic_condition(cond, "condition of 'do-while'-statement");
9303         expect(';');
9304
9305         POP_SCOPE();
9306         POP_PARENT();
9307         return statement;
9308 }
9309
9310 /**
9311  * Parse a for statement.
9312  */
9313 static statement_t *parse_for(void)
9314 {
9315         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9316
9317         eat(T_for);
9318
9319         PUSH_PARENT(statement);
9320         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9321
9322         add_anchor_token(')');
9323         expect('(');
9324
9325         PUSH_EXTENSION();
9326
9327         if (accept(';')) {
9328         } else if (is_declaration_specifier(&token)) {
9329                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9330         } else {
9331                 add_anchor_token(';');
9332                 expression_t *const init = parse_expression();
9333                 statement->fors.initialisation = init;
9334                 mark_vars_read(init, ENT_ANY);
9335                 if (!expression_has_effect(init)) {
9336                         warningf(WARN_UNUSED_VALUE, &init->base.pos, "initialisation of 'for'-statement has no effect");
9337                 }
9338                 rem_anchor_token(';');
9339                 expect(';');
9340         }
9341
9342         POP_EXTENSION();
9343
9344         if (token.kind != ';') {
9345                 add_anchor_token(';');
9346                 expression_t *const cond = parse_expression();
9347                 statement->fors.condition = cond;
9348                 /* §6.8.5:2    The controlling expression of an iteration statement
9349                  *             shall have scalar type. */
9350                 semantic_condition(cond, "condition of 'for'-statement");
9351                 mark_vars_read(cond, NULL);
9352                 rem_anchor_token(';');
9353         }
9354         expect(';');
9355         if (token.kind != ')') {
9356                 expression_t *const step = parse_expression();
9357                 statement->fors.step = step;
9358                 mark_vars_read(step, ENT_ANY);
9359                 if (!expression_has_effect(step)) {
9360                         warningf(WARN_UNUSED_VALUE, &step->base.pos, "step of 'for'-statement has no effect");
9361                 }
9362         }
9363         rem_anchor_token(')');
9364         expect(')');
9365         statement->fors.body = parse_loop_body(statement);
9366
9367         POP_SCOPE();
9368         POP_PARENT();
9369         return statement;
9370 }
9371
9372 /**
9373  * Parse a goto statement.
9374  */
9375 static statement_t *parse_goto(void)
9376 {
9377         statement_t *statement;
9378         if (GNU_MODE && look_ahead(1)->kind == '*') {
9379                 statement = allocate_statement_zero(STATEMENT_COMPUTED_GOTO);
9380                 eat(T_goto);
9381                 eat('*');
9382
9383                 expression_t *expression = parse_expression();
9384                 mark_vars_read(expression, NULL);
9385
9386                 /* Argh: although documentation says the expression must be of type void*,
9387                  * gcc accepts anything that can be casted into void* without error */
9388                 type_t *type = expression->base.type;
9389
9390                 if (type != type_error_type) {
9391                         if (!is_type_pointer(type) && !is_type_integer(type)) {
9392                                 errorf(&expression->base.pos, "cannot convert to a pointer type");
9393                         } else if (type != type_void_ptr) {
9394                                 warningf(WARN_OTHER, &expression->base.pos, "type of computed goto expression should be 'void*' not '%T'", type);
9395                         }
9396                         expression = create_implicit_cast(expression, type_void_ptr);
9397                 }
9398
9399                 statement->computed_goto.expression = expression;
9400         } else {
9401                 statement = allocate_statement_zero(STATEMENT_GOTO);
9402                 eat(T_goto);
9403
9404                 label_t *const label = get_label("while parsing goto");
9405                 if (label) {
9406                         label->n_users        += 1;
9407                         label->used            = true;
9408                         statement->gotos.label = label;
9409
9410                         /* remember the goto's in a list for later checking */
9411                         *goto_anchor = &statement->gotos;
9412                         goto_anchor  = &statement->gotos.next;
9413                 } else {
9414                         statement->gotos.label = &allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym_anonymous, &builtin_position)->label;
9415                 }
9416         }
9417
9418         expect(';');
9419         return statement;
9420 }
9421
9422 /**
9423  * Parse a continue statement.
9424  */
9425 static statement_t *parse_continue(void)
9426 {
9427         if (current_loop == NULL) {
9428                 errorf(HERE, "continue statement not within loop");
9429         }
9430
9431         statement_t *statement = allocate_statement_zero(STATEMENT_CONTINUE);
9432
9433         eat(T_continue);
9434         expect(';');
9435         return statement;
9436 }
9437
9438 /**
9439  * Parse a break statement.
9440  */
9441 static statement_t *parse_break(void)
9442 {
9443         if (current_switch == NULL && current_loop == NULL) {
9444                 errorf(HERE, "break statement not within loop or switch");
9445         }
9446
9447         statement_t *statement = allocate_statement_zero(STATEMENT_BREAK);
9448
9449         eat(T_break);
9450         expect(';');
9451         return statement;
9452 }
9453
9454 /**
9455  * Parse a __leave statement.
9456  */
9457 static statement_t *parse_leave_statement(void)
9458 {
9459         if (current_try == NULL) {
9460                 errorf(HERE, "__leave statement not within __try");
9461         }
9462
9463         statement_t *statement = allocate_statement_zero(STATEMENT_LEAVE);
9464
9465         eat(T___leave);
9466         expect(';');
9467         return statement;
9468 }
9469
9470 /**
9471  * Check if a given entity represents a local variable.
9472  */
9473 static bool is_local_variable(const entity_t *entity)
9474 {
9475         if (entity->kind != ENTITY_VARIABLE)
9476                 return false;
9477
9478         switch ((storage_class_tag_t) entity->declaration.storage_class) {
9479         case STORAGE_CLASS_AUTO:
9480         case STORAGE_CLASS_REGISTER: {
9481                 const type_t *type = skip_typeref(entity->declaration.type);
9482                 if (is_type_function(type)) {
9483                         return false;
9484                 } else {
9485                         return true;
9486                 }
9487         }
9488         default:
9489                 return false;
9490         }
9491 }
9492
9493 /**
9494  * Check if a given expression represents a local variable.
9495  */
9496 static bool expression_is_local_variable(const expression_t *expression)
9497 {
9498         if (expression->base.kind != EXPR_REFERENCE) {
9499                 return false;
9500         }
9501         const entity_t *entity = expression->reference.entity;
9502         return is_local_variable(entity);
9503 }
9504
9505 static void err_or_warn(position_t const *const pos, char const *const msg)
9506 {
9507         if (c_mode & _CXX || strict_mode) {
9508                 errorf(pos, msg);
9509         } else {
9510                 warningf(WARN_OTHER, pos, msg);
9511         }
9512 }
9513
9514 /**
9515  * Parse a return statement.
9516  */
9517 static statement_t *parse_return(void)
9518 {
9519         statement_t *statement = allocate_statement_zero(STATEMENT_RETURN);
9520         eat(T_return);
9521
9522         expression_t *return_value = NULL;
9523         if (token.kind != ';') {
9524                 return_value = parse_expression();
9525                 mark_vars_read(return_value, NULL);
9526         }
9527
9528         const type_t *const func_type = skip_typeref(current_function->base.type);
9529         assert(is_type_function(func_type));
9530         type_t *const return_type = skip_typeref(func_type->function.return_type);
9531
9532         position_t const *const pos = &statement->base.pos;
9533         if (return_value != NULL) {
9534                 type_t *return_value_type = skip_typeref(return_value->base.type);
9535
9536                 if (is_type_void(return_type)) {
9537                         if (!is_type_void(return_value_type)) {
9538                                 /* ISO/IEC 14882:1998(E) §6.6.3:2 */
9539                                 /* Only warn in C mode, because GCC does the same */
9540                                 err_or_warn(pos, "'return' with a value, in function returning 'void'");
9541                         } else if (!(c_mode & _CXX)) { /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9542                                 /* Only warn in C mode, because GCC does the same */
9543                                 err_or_warn(pos, "'return' with expression in function returning 'void'");
9544                         }
9545                 } else {
9546                         assign_error_t error = semantic_assign(return_type, return_value);
9547                         report_assign_error(error, return_type, return_value, "'return'",
9548                                             pos);
9549                 }
9550                 return_value = create_implicit_cast(return_value, return_type);
9551                 /* check for returning address of a local var */
9552                 if (return_value != NULL && return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
9553                         const expression_t *expression = return_value->unary.value;
9554                         if (expression_is_local_variable(expression)) {
9555                                 warningf(WARN_OTHER, pos, "function returns address of local variable");
9556                         }
9557                 }
9558         } else if (!is_type_void(return_type)) {
9559                 /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9560                 err_or_warn(pos, "'return' without value, in function returning non-void");
9561         }
9562         statement->returns.value = return_value;
9563
9564         expect(';');
9565         return statement;
9566 }
9567
9568 /**
9569  * Parse a declaration statement.
9570  */
9571 static statement_t *parse_declaration_statement(void)
9572 {
9573         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9574
9575         entity_t *before = current_scope->last_entity;
9576         if (GNU_MODE) {
9577                 parse_external_declaration();
9578         } else {
9579                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9580         }
9581
9582         declaration_statement_t *const decl  = &statement->declaration;
9583         entity_t                *const begin =
9584                 before != NULL ? before->base.next : current_scope->entities;
9585         decl->declarations_begin = begin;
9586         decl->declarations_end   = begin != NULL ? current_scope->last_entity : NULL;
9587
9588         return statement;
9589 }
9590
9591 /**
9592  * Parse an expression statement, i.e. expr ';'.
9593  */
9594 static statement_t *parse_expression_statement(void)
9595 {
9596         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
9597
9598         expression_t *const expr         = parse_expression();
9599         statement->expression.expression = expr;
9600         mark_vars_read(expr, ENT_ANY);
9601
9602         expect(';');
9603         return statement;
9604 }
9605
9606 /**
9607  * Parse a microsoft __try { } __finally { } or
9608  * __try{ } __except() { }
9609  */
9610 static statement_t *parse_ms_try_statment(void)
9611 {
9612         statement_t *statement = allocate_statement_zero(STATEMENT_MS_TRY);
9613         eat(T___try);
9614
9615         PUSH_PARENT(statement);
9616
9617         ms_try_statement_t *rem = current_try;
9618         current_try = &statement->ms_try;
9619         statement->ms_try.try_statement = parse_compound_statement(false);
9620         current_try = rem;
9621
9622         POP_PARENT();
9623
9624         if (accept(T___except)) {
9625                 expression_t *const expr = parse_condition();
9626                 type_t       *      type = skip_typeref(expr->base.type);
9627                 if (is_type_integer(type)) {
9628                         type = promote_integer(type);
9629                 } else if (is_type_valid(type)) {
9630                         errorf(&expr->base.pos,
9631                                "__expect expression is not an integer, but '%T'", type);
9632                         type = type_error_type;
9633                 }
9634                 statement->ms_try.except_expression = create_implicit_cast(expr, type);
9635         } else if (!accept(T__finally)) {
9636                 parse_error_expected("while parsing __try statement", T___except, T___finally, NULL);
9637         }
9638         statement->ms_try.final_statement = parse_compound_statement(false);
9639         return statement;
9640 }
9641
9642 static statement_t *parse_empty_statement(void)
9643 {
9644         warningf(WARN_EMPTY_STATEMENT, HERE, "statement is empty");
9645         statement_t *const statement = create_empty_statement();
9646         eat(';');
9647         return statement;
9648 }
9649
9650 static statement_t *parse_local_label_declaration(void)
9651 {
9652         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9653
9654         eat(T___label__);
9655
9656         entity_t *begin   = NULL;
9657         entity_t *end     = NULL;
9658         entity_t **anchor = &begin;
9659         add_anchor_token(';');
9660         add_anchor_token(',');
9661         do {
9662                 position_t pos;
9663                 symbol_t *const symbol = expect_identifier("while parsing local label declaration", &pos);
9664                 if (symbol) {
9665                         entity_t *entity = get_entity(symbol, NAMESPACE_LABEL);
9666                         if (entity != NULL && entity->base.parent_scope == current_scope) {
9667                                 position_t const *const ppos = &entity->base.pos;
9668                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
9669                         } else {
9670                                 entity = allocate_entity_zero(ENTITY_LOCAL_LABEL, NAMESPACE_LABEL, symbol, &pos);
9671                                 entity->base.parent_scope = current_scope;
9672
9673                                 *anchor = entity;
9674                                 anchor  = &entity->base.next;
9675                                 end     = entity;
9676
9677                                 environment_push(entity);
9678                         }
9679                 }
9680         } while (accept(','));
9681         rem_anchor_token(',');
9682         rem_anchor_token(';');
9683         expect(';');
9684         statement->declaration.declarations_begin = begin;
9685         statement->declaration.declarations_end   = end;
9686         return statement;
9687 }
9688
9689 static void parse_namespace_definition(void)
9690 {
9691         eat(T_namespace);
9692
9693         entity_t *entity = NULL;
9694         symbol_t *symbol = NULL;
9695
9696         if (token.kind == T_IDENTIFIER) {
9697                 symbol = token.base.symbol;
9698                 entity = get_entity(symbol, NAMESPACE_NORMAL);
9699                 if (entity && entity->kind != ENTITY_NAMESPACE) {
9700                         entity = NULL;
9701                         if (entity->base.parent_scope == current_scope && is_entity_valid(entity)) {
9702                                 error_redefined_as_different_kind(HERE, entity, ENTITY_NAMESPACE);
9703                         }
9704                 }
9705                 eat(T_IDENTIFIER);
9706         }
9707
9708         if (entity == NULL) {
9709                 entity = allocate_entity_zero(ENTITY_NAMESPACE, NAMESPACE_NORMAL, symbol, HERE);
9710                 entity->base.parent_scope = current_scope;
9711         }
9712
9713         if (token.kind == '=') {
9714                 /* TODO: parse namespace alias */
9715                 panic("namespace alias definition not supported yet");
9716         }
9717
9718         environment_push(entity);
9719         append_entity(current_scope, entity);
9720
9721         PUSH_SCOPE(&entity->namespacee.members);
9722         PUSH_CURRENT_ENTITY(entity);
9723
9724         add_anchor_token('}');
9725         expect('{');
9726         parse_externals();
9727         rem_anchor_token('}');
9728         expect('}');
9729
9730         POP_CURRENT_ENTITY();
9731         POP_SCOPE();
9732 }
9733
9734 /**
9735  * Parse a statement.
9736  * There's also parse_statement() which additionally checks for
9737  * "statement has no effect" warnings
9738  */
9739 static statement_t *intern_parse_statement(void)
9740 {
9741         /* declaration or statement */
9742         statement_t *statement;
9743         switch (token.kind) {
9744         case T_IDENTIFIER: {
9745                 token_kind_t la1_type = (token_kind_t)look_ahead(1)->kind;
9746                 if (la1_type == ':') {
9747                         statement = parse_label_statement();
9748                 } else if (is_typedef_symbol(token.base.symbol)) {
9749                         statement = parse_declaration_statement();
9750                 } else {
9751                         /* it's an identifier, the grammar says this must be an
9752                          * expression statement. However it is common that users mistype
9753                          * declaration types, so we guess a bit here to improve robustness
9754                          * for incorrect programs */
9755                         switch (la1_type) {
9756                         case '&':
9757                         case '*':
9758                                 if (get_entity(token.base.symbol, NAMESPACE_NORMAL) != NULL) {
9759                         default:
9760                                         statement = parse_expression_statement();
9761                                 } else {
9762                         DECLARATION_START
9763                         case T_IDENTIFIER:
9764                                         statement = parse_declaration_statement();
9765                                 }
9766                                 break;
9767                         }
9768                 }
9769                 break;
9770         }
9771
9772         case T___extension__: {
9773                 /* This can be a prefix to a declaration or an expression statement.
9774                  * We simply eat it now and parse the rest with tail recursion. */
9775                 PUSH_EXTENSION();
9776                 statement = intern_parse_statement();
9777                 POP_EXTENSION();
9778                 break;
9779         }
9780
9781         DECLARATION_START
9782                 statement = parse_declaration_statement();
9783                 break;
9784
9785         case T___label__:
9786                 statement = parse_local_label_declaration();
9787                 break;
9788
9789         case ';':         statement = parse_empty_statement();         break;
9790         case '{':         statement = parse_compound_statement(false); break;
9791         case T___leave:   statement = parse_leave_statement();         break;
9792         case T___try:     statement = parse_ms_try_statment();         break;
9793         case T_asm:       statement = parse_asm_statement();           break;
9794         case T_break:     statement = parse_break();                   break;
9795         case T_case:      statement = parse_case_statement();          break;
9796         case T_continue:  statement = parse_continue();                break;
9797         case T_default:   statement = parse_default_statement();       break;
9798         case T_do:        statement = parse_do();                      break;
9799         case T_for:       statement = parse_for();                     break;
9800         case T_goto:      statement = parse_goto();                    break;
9801         case T_if:        statement = parse_if();                      break;
9802         case T_return:    statement = parse_return();                  break;
9803         case T_switch:    statement = parse_switch();                  break;
9804         case T_while:     statement = parse_while();                   break;
9805
9806         EXPRESSION_START
9807                 statement = parse_expression_statement();
9808                 break;
9809
9810         default:
9811                 errorf(HERE, "unexpected token %K while parsing statement", &token);
9812                 statement = create_error_statement();
9813                 eat_until_anchor();
9814                 break;
9815         }
9816
9817         return statement;
9818 }
9819
9820 /**
9821  * parse a statement and emits "statement has no effect" warning if needed
9822  * (This is really a wrapper around intern_parse_statement with check for 1
9823  *  single warning. It is needed, because for statement expressions we have
9824  *  to avoid the warning on the last statement)
9825  */
9826 static statement_t *parse_statement(void)
9827 {
9828         statement_t *statement = intern_parse_statement();
9829
9830         if (statement->kind == STATEMENT_EXPRESSION) {
9831                 expression_t *expression = statement->expression.expression;
9832                 if (!expression_has_effect(expression)) {
9833                         warningf(WARN_UNUSED_VALUE, &expression->base.pos,
9834                                  "statement has no effect");
9835                 }
9836         }
9837
9838         return statement;
9839 }
9840
9841 /**
9842  * Parse a compound statement.
9843  */
9844 static statement_t *parse_compound_statement(bool inside_expression_statement)
9845 {
9846         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
9847
9848         PUSH_PARENT(statement);
9849         PUSH_SCOPE(&statement->compound.scope);
9850
9851         eat('{');
9852         add_anchor_token('}');
9853         /* tokens, which can start a statement */
9854         /* TODO MS, __builtin_FOO */
9855         add_anchor_token('!');
9856         add_anchor_token('&');
9857         add_anchor_token('(');
9858         add_anchor_token('*');
9859         add_anchor_token('+');
9860         add_anchor_token('-');
9861         add_anchor_token(';');
9862         add_anchor_token('{');
9863         add_anchor_token('~');
9864         add_anchor_token(T_CHARACTER_CONSTANT);
9865         add_anchor_token(T_COLONCOLON);
9866         add_anchor_token(T_IDENTIFIER);
9867         add_anchor_token(T_MINUSMINUS);
9868         add_anchor_token(T_NUMBER);
9869         add_anchor_token(T_PLUSPLUS);
9870         add_anchor_token(T_STRING_LITERAL);
9871         add_anchor_token(T__Alignof);
9872         add_anchor_token(T__Bool);
9873         add_anchor_token(T__Complex);
9874         add_anchor_token(T__Imaginary);
9875         add_anchor_token(T__Thread_local);
9876         add_anchor_token(T___PRETTY_FUNCTION__);
9877         add_anchor_token(T___attribute__);
9878         add_anchor_token(T___builtin_va_start);
9879         add_anchor_token(T___extension__);
9880         add_anchor_token(T___func__);
9881         add_anchor_token(T___imag__);
9882         add_anchor_token(T___label__);
9883         add_anchor_token(T___real__);
9884         add_anchor_token(T_asm);
9885         add_anchor_token(T_auto);
9886         add_anchor_token(T_bool);
9887         add_anchor_token(T_break);
9888         add_anchor_token(T_case);
9889         add_anchor_token(T_char);
9890         add_anchor_token(T_class);
9891         add_anchor_token(T_const);
9892         add_anchor_token(T_const_cast);
9893         add_anchor_token(T_continue);
9894         add_anchor_token(T_default);
9895         add_anchor_token(T_delete);
9896         add_anchor_token(T_double);
9897         add_anchor_token(T_do);
9898         add_anchor_token(T_dynamic_cast);
9899         add_anchor_token(T_enum);
9900         add_anchor_token(T_extern);
9901         add_anchor_token(T_false);
9902         add_anchor_token(T_float);
9903         add_anchor_token(T_for);
9904         add_anchor_token(T_goto);
9905         add_anchor_token(T_if);
9906         add_anchor_token(T_inline);
9907         add_anchor_token(T_int);
9908         add_anchor_token(T_long);
9909         add_anchor_token(T_new);
9910         add_anchor_token(T_operator);
9911         add_anchor_token(T_register);
9912         add_anchor_token(T_reinterpret_cast);
9913         add_anchor_token(T_restrict);
9914         add_anchor_token(T_return);
9915         add_anchor_token(T_short);
9916         add_anchor_token(T_signed);
9917         add_anchor_token(T_sizeof);
9918         add_anchor_token(T_static);
9919         add_anchor_token(T_static_cast);
9920         add_anchor_token(T_struct);
9921         add_anchor_token(T_switch);
9922         add_anchor_token(T_template);
9923         add_anchor_token(T_this);
9924         add_anchor_token(T_throw);
9925         add_anchor_token(T_true);
9926         add_anchor_token(T_try);
9927         add_anchor_token(T_typedef);
9928         add_anchor_token(T_typeid);
9929         add_anchor_token(T_typename);
9930         add_anchor_token(T_typeof);
9931         add_anchor_token(T_union);
9932         add_anchor_token(T_unsigned);
9933         add_anchor_token(T_using);
9934         add_anchor_token(T_void);
9935         add_anchor_token(T_volatile);
9936         add_anchor_token(T_wchar_t);
9937         add_anchor_token(T_while);
9938
9939         statement_t **anchor            = &statement->compound.statements;
9940         bool          only_decls_so_far = true;
9941         while (token.kind != '}' && token.kind != T_EOF) {
9942                 statement_t *sub_statement = intern_parse_statement();
9943                 if (sub_statement->kind == STATEMENT_ERROR) {
9944                         break;
9945                 }
9946
9947                 if (sub_statement->kind != STATEMENT_DECLARATION) {
9948                         only_decls_so_far = false;
9949                 } else if (!only_decls_so_far) {
9950                         position_t const *const pos = &sub_statement->base.pos;
9951                         warningf(WARN_DECLARATION_AFTER_STATEMENT, pos, "ISO C90 forbids mixed declarations and code");
9952                 }
9953
9954                 *anchor = sub_statement;
9955                 anchor  = &sub_statement->base.next;
9956         }
9957         expect('}');
9958
9959         /* look over all statements again to produce no effect warnings */
9960         if (is_warn_on(WARN_UNUSED_VALUE)) {
9961                 statement_t *sub_statement = statement->compound.statements;
9962                 for (; sub_statement != NULL; sub_statement = sub_statement->base.next) {
9963                         if (sub_statement->kind != STATEMENT_EXPRESSION)
9964                                 continue;
9965                         /* don't emit a warning for the last expression in an expression
9966                          * statement as it has always an effect */
9967                         if (inside_expression_statement && sub_statement->base.next == NULL)
9968                                 continue;
9969
9970                         expression_t *expression = sub_statement->expression.expression;
9971                         if (!expression_has_effect(expression)) {
9972                                 warningf(WARN_UNUSED_VALUE, &expression->base.pos,
9973                                          "statement has no effect");
9974                         }
9975                 }
9976         }
9977
9978         rem_anchor_token(T_while);
9979         rem_anchor_token(T_wchar_t);
9980         rem_anchor_token(T_volatile);
9981         rem_anchor_token(T_void);
9982         rem_anchor_token(T_using);
9983         rem_anchor_token(T_unsigned);
9984         rem_anchor_token(T_union);
9985         rem_anchor_token(T_typeof);
9986         rem_anchor_token(T_typename);
9987         rem_anchor_token(T_typeid);
9988         rem_anchor_token(T_typedef);
9989         rem_anchor_token(T_try);
9990         rem_anchor_token(T_true);
9991         rem_anchor_token(T_throw);
9992         rem_anchor_token(T_this);
9993         rem_anchor_token(T_template);
9994         rem_anchor_token(T_switch);
9995         rem_anchor_token(T_struct);
9996         rem_anchor_token(T_static_cast);
9997         rem_anchor_token(T_static);
9998         rem_anchor_token(T_sizeof);
9999         rem_anchor_token(T_signed);
10000         rem_anchor_token(T_short);
10001         rem_anchor_token(T_return);
10002         rem_anchor_token(T_restrict);
10003         rem_anchor_token(T_reinterpret_cast);
10004         rem_anchor_token(T_register);
10005         rem_anchor_token(T_operator);
10006         rem_anchor_token(T_new);
10007         rem_anchor_token(T_long);
10008         rem_anchor_token(T_int);
10009         rem_anchor_token(T_inline);
10010         rem_anchor_token(T_if);
10011         rem_anchor_token(T_goto);
10012         rem_anchor_token(T_for);
10013         rem_anchor_token(T_float);
10014         rem_anchor_token(T_false);
10015         rem_anchor_token(T_extern);
10016         rem_anchor_token(T_enum);
10017         rem_anchor_token(T_dynamic_cast);
10018         rem_anchor_token(T_do);
10019         rem_anchor_token(T_double);
10020         rem_anchor_token(T_delete);
10021         rem_anchor_token(T_default);
10022         rem_anchor_token(T_continue);
10023         rem_anchor_token(T_const_cast);
10024         rem_anchor_token(T_const);
10025         rem_anchor_token(T_class);
10026         rem_anchor_token(T_char);
10027         rem_anchor_token(T_case);
10028         rem_anchor_token(T_break);
10029         rem_anchor_token(T_bool);
10030         rem_anchor_token(T_auto);
10031         rem_anchor_token(T_asm);
10032         rem_anchor_token(T___real__);
10033         rem_anchor_token(T___label__);
10034         rem_anchor_token(T___imag__);
10035         rem_anchor_token(T___func__);
10036         rem_anchor_token(T___extension__);
10037         rem_anchor_token(T___builtin_va_start);
10038         rem_anchor_token(T___attribute__);
10039         rem_anchor_token(T___PRETTY_FUNCTION__);
10040         rem_anchor_token(T__Thread_local);
10041         rem_anchor_token(T__Imaginary);
10042         rem_anchor_token(T__Complex);
10043         rem_anchor_token(T__Bool);
10044         rem_anchor_token(T__Alignof);
10045         rem_anchor_token(T_STRING_LITERAL);
10046         rem_anchor_token(T_PLUSPLUS);
10047         rem_anchor_token(T_NUMBER);
10048         rem_anchor_token(T_MINUSMINUS);
10049         rem_anchor_token(T_IDENTIFIER);
10050         rem_anchor_token(T_COLONCOLON);
10051         rem_anchor_token(T_CHARACTER_CONSTANT);
10052         rem_anchor_token('~');
10053         rem_anchor_token('{');
10054         rem_anchor_token(';');
10055         rem_anchor_token('-');
10056         rem_anchor_token('+');
10057         rem_anchor_token('*');
10058         rem_anchor_token('(');
10059         rem_anchor_token('&');
10060         rem_anchor_token('!');
10061         rem_anchor_token('}');
10062
10063         POP_SCOPE();
10064         POP_PARENT();
10065         return statement;
10066 }
10067
10068 /**
10069  * Check for unused global static functions and variables
10070  */
10071 static void check_unused_globals(void)
10072 {
10073         if (!is_warn_on(WARN_UNUSED_FUNCTION) && !is_warn_on(WARN_UNUSED_VARIABLE))
10074                 return;
10075
10076         for (const entity_t *entity = file_scope->entities; entity != NULL;
10077              entity = entity->base.next) {
10078                 if (!is_declaration(entity))
10079                         continue;
10080
10081                 const declaration_t *declaration = &entity->declaration;
10082                 if (declaration->used                  ||
10083                     declaration->modifiers & DM_UNUSED ||
10084                     declaration->modifiers & DM_USED   ||
10085                     declaration->storage_class != STORAGE_CLASS_STATIC)
10086                         continue;
10087
10088                 warning_t   why;
10089                 char const *s;
10090                 if (entity->kind == ENTITY_FUNCTION) {
10091                         /* inhibit warning for static inline functions */
10092                         if (entity->function.is_inline)
10093                                 continue;
10094
10095                         why = WARN_UNUSED_FUNCTION;
10096                         s   = entity->function.body != NULL ? "defined" : "declared";
10097                 } else {
10098                         why = WARN_UNUSED_VARIABLE;
10099                         s   = "defined";
10100                 }
10101
10102                 warningf(why, &declaration->base.pos, "'%#N' %s but not used", entity, s);
10103         }
10104 }
10105
10106 static void parse_global_asm(void)
10107 {
10108         statement_t *statement = allocate_statement_zero(STATEMENT_ASM);
10109
10110         eat(T_asm);
10111         add_anchor_token(';');
10112         add_anchor_token(')');
10113         add_anchor_token(T_STRING_LITERAL);
10114         expect('(');
10115
10116         rem_anchor_token(T_STRING_LITERAL);
10117         statement->asms.asm_text = parse_string_literals("global asm");
10118         statement->base.next     = unit->global_asm;
10119         unit->global_asm         = statement;
10120
10121         rem_anchor_token(')');
10122         expect(')');
10123         rem_anchor_token(';');
10124         expect(';');
10125 }
10126
10127 static void parse_linkage_specification(void)
10128 {
10129         eat(T_extern);
10130
10131         position_t  const pos     = *HERE;
10132         char const *const linkage = parse_string_literals(NULL).begin;
10133
10134         linkage_kind_t old_linkage = current_linkage;
10135         linkage_kind_t new_linkage;
10136         if (streq(linkage, "C")) {
10137                 new_linkage = LINKAGE_C;
10138         } else if (streq(linkage, "C++")) {
10139                 new_linkage = LINKAGE_CXX;
10140         } else {
10141                 errorf(&pos, "linkage string \"%s\" not recognized", linkage);
10142                 new_linkage = LINKAGE_C;
10143         }
10144         current_linkage = new_linkage;
10145
10146         if (accept('{')) {
10147                 parse_externals();
10148                 expect('}');
10149         } else {
10150                 parse_external();
10151         }
10152
10153         assert(current_linkage == new_linkage);
10154         current_linkage = old_linkage;
10155 }
10156
10157 static void parse_external(void)
10158 {
10159         switch (token.kind) {
10160                 case T_extern:
10161                         if (look_ahead(1)->kind == T_STRING_LITERAL) {
10162                                 parse_linkage_specification();
10163                         } else {
10164                 DECLARATION_START_NO_EXTERN
10165                 case T_IDENTIFIER:
10166                 case T___extension__:
10167                 /* tokens below are for implicit int */
10168                 case '&':  /* & x; -> int& x; (and error later, because C++ has no
10169                               implicit int) */
10170                 case '*':  /* * x; -> int* x; */
10171                 case '(':  /* (x); -> int (x); */
10172                                 PUSH_EXTENSION();
10173                                 parse_external_declaration();
10174                                 POP_EXTENSION();
10175                         }
10176                         return;
10177
10178                 case T_asm:
10179                         parse_global_asm();
10180                         return;
10181
10182                 case T_namespace:
10183                         parse_namespace_definition();
10184                         return;
10185
10186                 case ';':
10187                         if (!strict_mode) {
10188                                 warningf(WARN_STRAY_SEMICOLON, HERE, "stray ';' outside of function");
10189                                 eat(';');
10190                                 return;
10191                         }
10192                         /* FALLTHROUGH */
10193
10194                 default:
10195                         errorf(HERE, "stray %K outside of function", &token);
10196                         if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10197                                 eat_until_matching_token(token.kind);
10198                         next_token();
10199                         return;
10200         }
10201 }
10202
10203 static void parse_externals(void)
10204 {
10205         add_anchor_token('}');
10206         add_anchor_token(T_EOF);
10207
10208 #ifndef NDEBUG
10209         /* make a copy of the anchor set, so we can check if it is restored after parsing */
10210         unsigned short token_anchor_copy[T_LAST_TOKEN];
10211         memcpy(token_anchor_copy, token_anchor_set, sizeof(token_anchor_copy));
10212 #endif
10213
10214         while (token.kind != T_EOF && token.kind != '}') {
10215 #ifndef NDEBUG
10216                 for (int i = 0; i < T_LAST_TOKEN; ++i) {
10217                         unsigned short count = token_anchor_set[i] - token_anchor_copy[i];
10218                         if (count != 0) {
10219                                 /* the anchor set and its copy differs */
10220                                 internal_errorf(HERE, "Leaked anchor token %k %d times", i, count);
10221                         }
10222                 }
10223                 if (in_gcc_extension) {
10224                         /* an gcc extension scope was not closed */
10225                         internal_errorf(HERE, "Leaked __extension__");
10226                 }
10227 #endif
10228
10229                 parse_external();
10230         }
10231
10232         rem_anchor_token(T_EOF);
10233         rem_anchor_token('}');
10234 }
10235
10236 /**
10237  * Parse a translation unit.
10238  */
10239 static void parse_translation_unit(void)
10240 {
10241         add_anchor_token(T_EOF);
10242
10243         while (true) {
10244                 parse_externals();
10245
10246                 if (token.kind == T_EOF)
10247                         break;
10248
10249                 errorf(HERE, "stray %K outside of function", &token);
10250                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10251                         eat_until_matching_token(token.kind);
10252                 next_token();
10253         }
10254 }
10255
10256 void set_default_visibility(elf_visibility_tag_t visibility)
10257 {
10258         default_visibility = visibility;
10259 }
10260
10261 /**
10262  * Parse the input.
10263  *
10264  * @return  the translation unit or NULL if errors occurred.
10265  */
10266 void start_parsing(void)
10267 {
10268         environment_stack = NEW_ARR_F(stack_entry_t, 0);
10269         label_stack       = NEW_ARR_F(stack_entry_t, 0);
10270
10271         print_to_file(stderr);
10272
10273         assert(unit == NULL);
10274         unit = allocate_ast_zero(sizeof(unit[0]));
10275
10276         assert(file_scope == NULL);
10277         file_scope = &unit->scope;
10278
10279         assert(current_scope == NULL);
10280         scope_push(&unit->scope);
10281
10282         create_gnu_builtins();
10283         if (c_mode & _MS)
10284                 create_microsoft_intrinsics();
10285 }
10286
10287 translation_unit_t *finish_parsing(void)
10288 {
10289         assert(current_scope == &unit->scope);
10290         scope_pop(NULL);
10291
10292         assert(file_scope == &unit->scope);
10293         check_unused_globals();
10294         file_scope = NULL;
10295
10296         DEL_ARR_F(environment_stack);
10297         DEL_ARR_F(label_stack);
10298
10299         translation_unit_t *result = unit;
10300         unit = NULL;
10301         return result;
10302 }
10303
10304 /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
10305  * are given length one. */
10306 static void complete_incomplete_arrays(void)
10307 {
10308         size_t n = ARR_LEN(incomplete_arrays);
10309         for (size_t i = 0; i != n; ++i) {
10310                 declaration_t *const decl = incomplete_arrays[i];
10311                 type_t        *const type = skip_typeref(decl->type);
10312
10313                 if (!is_type_incomplete(type))
10314                         continue;
10315
10316                 position_t const *const pos = &decl->base.pos;
10317                 warningf(WARN_OTHER, pos, "array '%#N' assumed to have one element", (entity_t const*)decl);
10318
10319                 type_t *const new_type = duplicate_type(type);
10320                 new_type->array.size_constant     = true;
10321                 new_type->array.has_implicit_size = true;
10322                 new_type->array.size              = 1;
10323
10324                 type_t *const result = identify_new_type(new_type);
10325
10326                 decl->type = result;
10327         }
10328 }
10329
10330 static void prepare_main_collect2(entity_t *const entity)
10331 {
10332         PUSH_SCOPE(&entity->function.body->compound.scope);
10333
10334         // create call to __main
10335         symbol_t *symbol         = symbol_table_insert("__main");
10336         entity_t *subsubmain_ent
10337                 = create_implicit_function(symbol, &builtin_position);
10338
10339         expression_t *ref     = allocate_expression_zero(EXPR_REFERENCE);
10340         type_t       *ftype   = subsubmain_ent->declaration.type;
10341         ref->base.pos         = builtin_position;
10342         ref->base.type        = make_pointer_type(ftype, TYPE_QUALIFIER_NONE);
10343         ref->reference.entity = subsubmain_ent;
10344
10345         expression_t *call  = allocate_expression_zero(EXPR_CALL);
10346         call->base.pos      = builtin_position;
10347         call->base.type     = type_void;
10348         call->call.function = ref;
10349
10350         statement_t *expr_statement = allocate_statement_zero(STATEMENT_EXPRESSION);
10351         expr_statement->base.pos              = builtin_position;
10352         expr_statement->expression.expression = call;
10353
10354         statement_t *const body = entity->function.body;
10355         assert(body->kind == STATEMENT_COMPOUND);
10356         compound_statement_t *compounds = &body->compound;
10357
10358         expr_statement->base.next = compounds->statements;
10359         compounds->statements     = expr_statement;
10360
10361         POP_SCOPE();
10362 }
10363
10364 void parse(void)
10365 {
10366         lookahead_bufpos = 0;
10367         for (int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
10368                 next_token();
10369         }
10370         current_linkage   = c_mode & _CXX ? LINKAGE_CXX : LINKAGE_C;
10371         incomplete_arrays = NEW_ARR_F(declaration_t*, 0);
10372         parse_translation_unit();
10373         complete_incomplete_arrays();
10374         DEL_ARR_F(incomplete_arrays);
10375         incomplete_arrays = NULL;
10376 }
10377
10378 /**
10379  * Initialize the parser.
10380  */
10381 void init_parser(void)
10382 {
10383         memset(token_anchor_set, 0, sizeof(token_anchor_set));
10384
10385         init_expression_parsers();
10386         obstack_init(&temp_obst);
10387 }
10388
10389 /**
10390  * Terminate the parser.
10391  */
10392 void exit_parser(void)
10393 {
10394         obstack_free(&temp_obst, NULL);
10395 }