nsz Git - cparser/blob - parser.c

   1 /*
   2  * This file is part of cparser.
   3  * Copyright (C) 2007-2009 Matthias Braun <matze@braunis.de>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18  * 02111-1307, USA.
  19  */
  20 #include <config.h>
  21
  22 #include <assert.h>
  23 #include <stdarg.h>
  24 #include <stdbool.h>
  25
  26 #include "adt/strutil.h"
  27 #include "parser.h"
  28 #include "diagnostic.h"
  29 #include "format_check.h"
  30 #include "lexer.h"
  31 #include "symbol_t.h"
  32 #include "token_t.h"
  33 #include "types.h"
  34 #include "type_t.h"
  35 #include "type_hash.h"
  36 #include "ast_t.h"
  37 #include "entity_t.h"
  38 #include "attribute_t.h"
  39 #include "lang_features.h"
  40 #include "walk.h"
  41 #include "warning.h"
  42 #include "printer.h"
  43 #include "adt/bitfiddle.h"
  44 #include "adt/error.h"
  45 #include "adt/array.h"
  46
  47 //#define PRINT_TOKENS
  48 #define MAX_LOOKAHEAD 1
  49
  50 typedef struct {
  51         entity_t           *old_entity;
  52         symbol_t           *symbol;
  53         entity_namespace_t  namespc;
  54 } stack_entry_t;
  55
  56 typedef struct declaration_specifiers_t  declaration_specifiers_t;
  57 struct declaration_specifiers_t {
  58         source_position_t  source_position;
  59         storage_class_t    storage_class;
  60         unsigned char      alignment;         /**< Alignment, 0 if not set. */
  61         bool               is_inline    : 1;
  62         bool               thread_local : 1;  /**< GCC __thread */
  63         attribute_t       *attributes;        /**< list of attributes */
  64         type_t            *type;
  65 };
  66
  67 /**
  68  * An environment for parsing initializers (and compound literals).
  69  */
  70 typedef struct parse_initializer_env_t {
  71         type_t     *type;   /**< the type of the initializer. In case of an
  72                                  array type with unspecified size this gets
  73                                  adjusted to the actual size. */
  74         entity_t   *entity; /**< the variable that is initialized if any */
  75         bool        must_be_constant;
  76 } parse_initializer_env_t;
  77
  78 typedef entity_t* (*parsed_declaration_func) (entity_t *declaration, bool is_definition);
  79
  80 /** The current token. */
  81 static token_t              token;
  82 /** The lookahead ring-buffer. */
  83 static token_t              lookahead_buffer[MAX_LOOKAHEAD];
  84 /** Position of the next token in the lookahead buffer. */
  85 static size_t               lookahead_bufpos;
  86 static stack_entry_t       *environment_stack = NULL;
  87 static stack_entry_t       *label_stack       = NULL;
  88 static scope_t             *file_scope        = NULL;
  89 static scope_t             *current_scope     = NULL;
  90 /** Point to the current function declaration if inside a function. */
  91 static function_t          *current_function  = NULL;
  92 static entity_t            *current_entity    = NULL;
  93 static switch_statement_t  *current_switch    = NULL;
  94 static statement_t         *current_loop      = NULL;
  95 static statement_t         *current_parent    = NULL;
  96 static ms_try_statement_t  *current_try       = NULL;
  97 static linkage_kind_t       current_linkage;
  98 static goto_statement_t    *goto_first        = NULL;
  99 static goto_statement_t   **goto_anchor       = NULL;
 100 static label_statement_t   *label_first       = NULL;
 101 static label_statement_t  **label_anchor      = NULL;
 102 /** current translation unit. */
 103 static translation_unit_t  *unit              = NULL;
 104 /** true if we are in an __extension__ context. */
 105 static bool                 in_gcc_extension  = false;
 106 static struct obstack       temp_obst;
 107 static entity_t            *anonymous_entity;
 108 static declaration_t      **incomplete_arrays;
 109 static elf_visibility_tag_t default_visibility = ELF_VISIBILITY_DEFAULT;
 110
 111
 112 #define PUSH_CURRENT_ENTITY(entity) \
 113         entity_t *const new_current_entity = (entity); \
 114         entity_t *const old_current_entity = current_entity; \
 115         ((void)(current_entity = new_current_entity))
 116 #define POP_CURRENT_ENTITY() (assert(current_entity == new_current_entity), (void)(current_entity = old_current_entity))
 117
 118 #define PUSH_PARENT(stmt) \
 119         statement_t *const new_parent = (stmt); \
 120         statement_t *const old_parent = current_parent; \
 121         ((void)(current_parent = new_parent))
 122 #define POP_PARENT() (assert(current_parent == new_parent), (void)(current_parent = old_parent))
 123
 124 #define PUSH_SCOPE(scope) \
 125         size_t   const top       = environment_top(); \
 126         scope_t *const new_scope = (scope); \
 127         scope_t *const old_scope = (new_scope ? scope_push(new_scope) : NULL)
 128 #define PUSH_SCOPE_STATEMENT(scope) PUSH_SCOPE(c_mode & (_C99 | _CXX) ? (scope) : NULL)
 129 #define POP_SCOPE() (new_scope ? assert(current_scope == new_scope), scope_pop(old_scope), environment_pop_to(top) : (void)0)
 130
 131 #define PUSH_EXTENSION() \
 132         (void)0; \
 133         bool const old_gcc_extension = in_gcc_extension; \
 134         while (next_if(T___extension__)) { \
 135                 in_gcc_extension = true; \
 136         } \
 137         do {} while (0)
 138 #define POP_EXTENSION() \
 139         ((void)(in_gcc_extension = old_gcc_extension))
 140
 141 /** special symbol used for anonymous entities. */
 142 static symbol_t *sym_anonymous = NULL;
 143
 144 /** The token anchor set */
 145 static unsigned short token_anchor_set[T_LAST_TOKEN];
 146
 147 /** The current source position. */
 148 #define HERE (&token.base.source_position)
 149
 150 /** true if we are in GCC mode. */
 151 #define GNU_MODE ((c_mode & _GNUC) || in_gcc_extension)
 152
 153 static statement_t *parse_compound_statement(bool inside_expression_statement);
 154 static statement_t *parse_statement(void);
 155
 156 static expression_t *parse_subexpression(precedence_t);
 157 static expression_t *parse_expression(void);
 158 static type_t       *parse_typename(void);
 159 static void          parse_externals(void);
 160 static void          parse_external(void);
 161
 162 static void parse_compound_type_entries(compound_t *compound_declaration);
 163
 164 static void check_call_argument(type_t          *expected_type,
 165                                                                 call_argument_t *argument, unsigned pos);
 166
 167 typedef enum declarator_flags_t {
 168         DECL_FLAGS_NONE             = 0,
 169         DECL_MAY_BE_ABSTRACT        = 1U << 0,
 170         DECL_CREATE_COMPOUND_MEMBER = 1U << 1,
 171         DECL_IS_PARAMETER           = 1U << 2
 172 } declarator_flags_t;
 173
 174 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
 175                                   declarator_flags_t flags);
 176
 177 static void semantic_comparison(binary_expression_t *expression);
 178
 179 #define STORAGE_CLASSES       \
 180         STORAGE_CLASSES_NO_EXTERN \
 181         case T_extern:
 182
 183 #define STORAGE_CLASSES_NO_EXTERN \
 184         case T_typedef:         \
 185         case T_static:          \
 186         case T_auto:            \
 187         case T_register:        \
 188         case T___thread:
 189
 190 #define TYPE_QUALIFIERS     \
 191         case T_const:           \
 192         case T_restrict:        \
 193         case T_volatile:        \
 194         case T_inline:          \
 195         case T__forceinline:    \
 196         case T___attribute__:
 197
 198 #define COMPLEX_SPECIFIERS  \
 199         case T__Complex:
 200 #define IMAGINARY_SPECIFIERS \
 201         case T__Imaginary:
 202
 203 #define TYPE_SPECIFIERS       \
 204         case T__Bool:             \
 205         case T___builtin_va_list: \
 206         case T___typeof__:        \
 207         case T__declspec:         \
 208         case T_bool:              \
 209         case T_char:              \
 210         case T_double:            \
 211         case T_enum:              \
 212         case T_float:             \
 213         case T_int:               \
 214         case T_long:              \
 215         case T_short:             \
 216         case T_signed:            \
 217         case T_struct:            \
 218         case T_union:             \
 219         case T_unsigned:          \
 220         case T_void:              \
 221         case T_wchar_t:           \
 222         case T__int8:             \
 223         case T__int16:            \
 224         case T__int32:            \
 225         case T__int64:            \
 226         case T__int128:           \
 227         COMPLEX_SPECIFIERS        \
 228         IMAGINARY_SPECIFIERS
 229
 230 #define DECLARATION_START   \
 231         STORAGE_CLASSES         \
 232         TYPE_QUALIFIERS         \
 233         TYPE_SPECIFIERS
 234
 235 #define DECLARATION_START_NO_EXTERN \
 236         STORAGE_CLASSES_NO_EXTERN       \
 237         TYPE_QUALIFIERS                 \
 238         TYPE_SPECIFIERS
 239
 240 #define EXPRESSION_START              \
 241         case '!':                         \
 242         case '&':                         \
 243         case '(':                         \
 244         case '*':                         \
 245         case '+':                         \
 246         case '-':                         \
 247         case '~':                         \
 248         case T_ANDAND:                    \
 249         case T_CHARACTER_CONSTANT:        \
 250         case T_FLOATINGPOINT:             \
 251         case T_INTEGER:                   \
 252         case T_MINUSMINUS:                \
 253         case T_PLUSPLUS:                  \
 254         case T_STRING_LITERAL:            \
 255         case T___FUNCDNAME__:             \
 256         case T___FUNCSIG__:               \
 257         case T___PRETTY_FUNCTION__:       \
 258         case T___alignof__:               \
 259         case T___builtin_classify_type:   \
 260         case T___builtin_constant_p:      \
 261         case T___builtin_isgreater:       \
 262         case T___builtin_isgreaterequal:  \
 263         case T___builtin_isless:          \
 264         case T___builtin_islessequal:     \
 265         case T___builtin_islessgreater:   \
 266         case T___builtin_isunordered:     \
 267         case T___builtin_offsetof:        \
 268         case T___builtin_va_arg:          \
 269         case T___builtin_va_copy:         \
 270         case T___builtin_va_start:        \
 271         case T___func__:                  \
 272         case T___noop:                    \
 273         case T__assume:                   \
 274         case T_delete:                    \
 275         case T_false:                     \
 276         case T_sizeof:                    \
 277         case T_throw:                     \
 278         case T_true:
 279
 280 /**
 281  * Returns the size of a statement node.
 282  *
 283  * @param kind  the statement kind
 284  */
 285 static size_t get_statement_struct_size(statement_kind_t kind)
 286 {
 287         static const size_t sizes[] = {
 288                 [STATEMENT_ERROR]         = sizeof(statement_base_t),
 289                 [STATEMENT_EMPTY]         = sizeof(statement_base_t),
 290                 [STATEMENT_COMPOUND]      = sizeof(compound_statement_t),
 291                 [STATEMENT_RETURN]        = sizeof(return_statement_t),
 292                 [STATEMENT_DECLARATION]   = sizeof(declaration_statement_t),
 293                 [STATEMENT_IF]            = sizeof(if_statement_t),
 294                 [STATEMENT_SWITCH]        = sizeof(switch_statement_t),
 295                 [STATEMENT_EXPRESSION]    = sizeof(expression_statement_t),
 296                 [STATEMENT_CONTINUE]      = sizeof(statement_base_t),
 297                 [STATEMENT_BREAK]         = sizeof(statement_base_t),
 298                 [STATEMENT_COMPUTED_GOTO] = sizeof(computed_goto_statement_t),
 299                 [STATEMENT_GOTO]          = sizeof(goto_statement_t),
 300                 [STATEMENT_LABEL]         = sizeof(label_statement_t),
 301                 [STATEMENT_CASE_LABEL]    = sizeof(case_label_statement_t),
 302                 [STATEMENT_WHILE]         = sizeof(while_statement_t),
 303                 [STATEMENT_DO_WHILE]      = sizeof(do_while_statement_t),
 304                 [STATEMENT_FOR]           = sizeof(for_statement_t),
 305                 [STATEMENT_ASM]           = sizeof(asm_statement_t),
 306                 [STATEMENT_MS_TRY]        = sizeof(ms_try_statement_t),
 307                 [STATEMENT_LEAVE]         = sizeof(leave_statement_t)
 308         };
 309         assert((size_t)kind < lengthof(sizes));
 310         assert(sizes[kind] != 0);
 311         return sizes[kind];
 312 }
 313
 314 /**
 315  * Returns the size of an expression node.
 316  *
 317  * @param kind  the expression kind
 318  */
 319 static size_t get_expression_struct_size(expression_kind_t kind)
 320 {
 321         static const size_t sizes[] = {
 322                 [EXPR_ERROR]                      = sizeof(expression_base_t),
 323                 [EXPR_REFERENCE]                  = sizeof(reference_expression_t),
 324                 [EXPR_ENUM_CONSTANT]              = sizeof(reference_expression_t),
 325                 [EXPR_LITERAL_BOOLEAN]            = sizeof(literal_expression_t),
 326                 [EXPR_LITERAL_INTEGER]            = sizeof(literal_expression_t),
 327                 [EXPR_LITERAL_FLOATINGPOINT]      = sizeof(literal_expression_t),
 328                 [EXPR_LITERAL_CHARACTER]          = sizeof(string_literal_expression_t),
 329                 [EXPR_LITERAL_WIDE_CHARACTER]     = sizeof(string_literal_expression_t),
 330                 [EXPR_STRING_LITERAL]             = sizeof(string_literal_expression_t),
 331                 [EXPR_COMPOUND_LITERAL]           = sizeof(compound_literal_expression_t),
 332                 [EXPR_CALL]                       = sizeof(call_expression_t),
 333                 [EXPR_UNARY_FIRST]                = sizeof(unary_expression_t),
 334                 [EXPR_BINARY_FIRST]               = sizeof(binary_expression_t),
 335                 [EXPR_CONDITIONAL]                = sizeof(conditional_expression_t),
 336                 [EXPR_SELECT]                     = sizeof(select_expression_t),
 337                 [EXPR_ARRAY_ACCESS]               = sizeof(array_access_expression_t),
 338                 [EXPR_SIZEOF]                     = sizeof(typeprop_expression_t),
 339                 [EXPR_ALIGNOF]                    = sizeof(typeprop_expression_t),
 340                 [EXPR_CLASSIFY_TYPE]              = sizeof(classify_type_expression_t),
 341                 [EXPR_FUNCNAME]                   = sizeof(funcname_expression_t),
 342                 [EXPR_BUILTIN_CONSTANT_P]         = sizeof(builtin_constant_expression_t),
 343                 [EXPR_BUILTIN_TYPES_COMPATIBLE_P] = sizeof(builtin_types_compatible_expression_t),
 344                 [EXPR_OFFSETOF]                   = sizeof(offsetof_expression_t),
 345                 [EXPR_VA_START]                   = sizeof(va_start_expression_t),
 346                 [EXPR_VA_ARG]                     = sizeof(va_arg_expression_t),
 347                 [EXPR_VA_COPY]                    = sizeof(va_copy_expression_t),
 348                 [EXPR_STATEMENT]                  = sizeof(statement_expression_t),
 349                 [EXPR_LABEL_ADDRESS]              = sizeof(label_address_expression_t),
 350         };
 351         if (kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
 352                 return sizes[EXPR_UNARY_FIRST];
 353         }
 354         if (kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
 355                 return sizes[EXPR_BINARY_FIRST];
 356         }
 357         assert((size_t)kind < lengthof(sizes));
 358         assert(sizes[kind] != 0);
 359         return sizes[kind];
 360 }
 361
 362 /**
 363  * Allocate a statement node of given kind and initialize all
 364  * fields with zero. Sets its source position to the position
 365  * of the current token.
 366  */
 367 static statement_t *allocate_statement_zero(statement_kind_t kind)
 368 {
 369         size_t       size = get_statement_struct_size(kind);
 370         statement_t *res  = allocate_ast_zero(size);
 371
 372         res->base.kind            = kind;
 373         res->base.parent          = current_parent;
 374         res->base.source_position = *HERE;
 375         return res;
 376 }
 377
 378 /**
 379  * Allocate an expression node of given kind and initialize all
 380  * fields with zero.
 381  *
 382  * @param kind  the kind of the expression to allocate
 383  */
 384 static expression_t *allocate_expression_zero(expression_kind_t kind)
 385 {
 386         size_t        size = get_expression_struct_size(kind);
 387         expression_t *res  = allocate_ast_zero(size);
 388
 389         res->base.kind            = kind;
 390         res->base.type            = type_error_type;
 391         res->base.source_position = *HERE;
 392         return res;
 393 }
 394
 395 /**
 396  * Creates a new invalid expression at the source position
 397  * of the current token.
 398  */
 399 static expression_t *create_error_expression(void)
 400 {
 401         expression_t *expression = allocate_expression_zero(EXPR_ERROR);
 402         expression->base.type = type_error_type;
 403         return expression;
 404 }
 405
 406 /**
 407  * Creates a new invalid statement.
 408  */
 409 static statement_t *create_error_statement(void)
 410 {
 411         return allocate_statement_zero(STATEMENT_ERROR);
 412 }
 413
 414 /**
 415  * Allocate a new empty statement.
 416  */
 417 static statement_t *create_empty_statement(void)
 418 {
 419         return allocate_statement_zero(STATEMENT_EMPTY);
 420 }
 421
 422 /**
 423  * Returns the size of an initializer node.
 424  *
 425  * @param kind  the initializer kind
 426  */
 427 static size_t get_initializer_size(initializer_kind_t kind)
 428 {
 429         static const size_t sizes[] = {
 430                 [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
 431                 [INITIALIZER_STRING]      = sizeof(initializer_string_t),
 432                 [INITIALIZER_WIDE_STRING] = sizeof(initializer_wide_string_t),
 433                 [INITIALIZER_LIST]        = sizeof(initializer_list_t),
 434                 [INITIALIZER_DESIGNATOR]  = sizeof(initializer_designator_t)
 435         };
 436         assert((size_t)kind < lengthof(sizes));
 437         assert(sizes[kind] != 0);
 438         return sizes[kind];
 439 }
 440
 441 /**
 442  * Allocate an initializer node of given kind and initialize all
 443  * fields with zero.
 444  */
 445 static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 446 {
 447         initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
 448         result->kind          = kind;
 449
 450         return result;
 451 }
 452
 453 /**
 454  * Returns the index of the top element of the environment stack.
 455  */
 456 static size_t environment_top(void)
 457 {
 458         return ARR_LEN(environment_stack);
 459 }
 460
 461 /**
 462  * Returns the index of the top element of the global label stack.
 463  */
 464 static size_t label_top(void)
 465 {
 466         return ARR_LEN(label_stack);
 467 }
 468
 469 /**
 470  * Return the next token.
 471  */
 472 static inline void next_token(void)
 473 {
 474         token                              = lookahead_buffer[lookahead_bufpos];
 475         lookahead_buffer[lookahead_bufpos] = lexer_token;
 476         lexer_next_token();
 477
 478         lookahead_bufpos = (lookahead_bufpos + 1) % MAX_LOOKAHEAD;
 479
 480 #ifdef PRINT_TOKENS
 481         print_token(stderr, &token);
 482         fprintf(stderr, "\n");
 483 #endif
 484 }
 485
 486 #define eat(token_kind) (assert(token.kind == (token_kind)), next_token())
 487
 488 static inline bool next_if(token_kind_t const type)
 489 {
 490         if (token.kind == type) {
 491                 eat(type);
 492                 return true;
 493         } else {
 494                 return false;
 495         }
 496 }
 497
 498 /**
 499  * Return the next token with a given lookahead.
 500  */
 501 static inline const token_t *look_ahead(size_t num)
 502 {
 503         assert(0 < num && num <= MAX_LOOKAHEAD);
 504         size_t pos = (lookahead_bufpos + num - 1) % MAX_LOOKAHEAD;
 505         return &lookahead_buffer[pos];
 506 }
 507
 508 /**
 509  * Adds a token type to the token type anchor set (a multi-set).
 510  */
 511 static void add_anchor_token(token_kind_t const token_kind)
 512 {
 513         assert(token_kind < T_LAST_TOKEN);
 514         ++token_anchor_set[token_kind];
 515 }
 516
 517 /**
 518  * Remove a token type from the token type anchor set (a multi-set).
 519  */
 520 static void rem_anchor_token(token_kind_t const token_kind)
 521 {
 522         assert(token_kind < T_LAST_TOKEN);
 523         assert(token_anchor_set[token_kind] != 0);
 524         --token_anchor_set[token_kind];
 525 }
 526
 527 /**
 528  * Eat tokens until a matching token type is found.
 529  */
 530 static void eat_until_matching_token(token_kind_t const type)
 531 {
 532         token_kind_t end_token;
 533         switch (type) {
 534                 case '(': end_token = ')';  break;
 535                 case '{': end_token = '}';  break;
 536                 case '[': end_token = ']';  break;
 537                 default:  end_token = type; break;
 538         }
 539
 540         unsigned parenthesis_count = 0;
 541         unsigned brace_count       = 0;
 542         unsigned bracket_count     = 0;
 543         while (token.kind        != end_token ||
 544                parenthesis_count != 0         ||
 545                brace_count       != 0         ||
 546                bracket_count     != 0) {
 547                 switch (token.kind) {
 548                 case T_EOF: return;
 549                 case '(': ++parenthesis_count; break;
 550                 case '{': ++brace_count;       break;
 551                 case '[': ++bracket_count;     break;
 552
 553                 case ')':
 554                         if (parenthesis_count > 0)
 555                                 --parenthesis_count;
 556                         goto check_stop;
 557
 558                 case '}':
 559                         if (brace_count > 0)
 560                                 --brace_count;
 561                         goto check_stop;
 562
 563                 case ']':
 564                         if (bracket_count > 0)
 565                                 --bracket_count;
 566 check_stop:
 567                         if (token.kind        == end_token &&
 568                             parenthesis_count == 0         &&
 569                             brace_count       == 0         &&
 570                             bracket_count     == 0)
 571                                 return;
 572                         break;
 573
 574                 default:
 575                         break;
 576                 }
 577                 next_token();
 578         }
 579 }
 580
 581 /**
 582  * Eat input tokens until an anchor is found.
 583  */
 584 static void eat_until_anchor(void)
 585 {
 586         while (token_anchor_set[token.kind] == 0) {
 587                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
 588                         eat_until_matching_token(token.kind);
 589                 next_token();
 590         }
 591 }
 592
 593 /**
 594  * Eat a whole block from input tokens.
 595  */
 596 static void eat_block(void)
 597 {
 598         eat_until_matching_token('{');
 599         next_if('}');
 600 }
 601
 602 /**
 603  * Report a parse error because an expected token was not found.
 604  */
 605 static
 606 #if defined __GNUC__ && __GNUC__ >= 4
 607 __attribute__((sentinel))
 608 #endif
 609 void parse_error_expected(const char *message, ...)
 610 {
 611         if (message != NULL) {
 612                 errorf(HERE, "%s", message);
 613         }
 614         va_list ap;
 615         va_start(ap, message);
 616         errorf(HERE, "got %K, expected %#k", &token, &ap, ", ");
 617         va_end(ap);
 618 }
 619
 620 /**
 621  * Report an incompatible type.
 622  */
 623 static void type_error_incompatible(const char *msg,
 624                 const source_position_t *source_position, type_t *type1, type_t *type2)
 625 {
 626         errorf(source_position, "%s, incompatible types: '%T' - '%T'",
 627                msg, type1, type2);
 628 }
 629
 630 static bool skip_till(token_kind_t const expected, char const *const context)
 631 {
 632         if (UNLIKELY(token.kind != expected)) {
 633                 parse_error_expected(context, expected, NULL);
 634                 add_anchor_token(expected);
 635                 eat_until_anchor();
 636                 rem_anchor_token(expected);
 637                 if (token.kind != expected)
 638                         return false;
 639         }
 640         return true;
 641 }
 642
 643 /**
 644  * Expect the current token is the expected token.
 645  * If not, generate an error and skip until the next anchor.
 646  */
 647 static void expect(token_kind_t const expected)
 648 {
 649         if (skip_till(expected, NULL))
 650                 eat(expected);
 651 }
 652
 653 static symbol_t *expect_identifier(char const *const context, source_position_t *const pos)
 654 {
 655         if (!skip_till(T_IDENTIFIER, context))
 656                 return NULL;
 657         symbol_t *const sym = token.base.symbol;
 658         if (pos)
 659                 *pos = *HERE;
 660         eat(T_IDENTIFIER);
 661         return sym;
 662 }
 663
 664 /**
 665  * Push a given scope on the scope stack and make it the
 666  * current scope
 667  */
 668 static scope_t *scope_push(scope_t *new_scope)
 669 {
 670         if (current_scope != NULL) {
 671                 new_scope->depth = current_scope->depth + 1;
 672         }
 673
 674         scope_t *old_scope = current_scope;
 675         current_scope      = new_scope;
 676         return old_scope;
 677 }
 678
 679 /**
 680  * Pop the current scope from the scope stack.
 681  */
 682 static void scope_pop(scope_t *old_scope)
 683 {
 684         current_scope = old_scope;
 685 }
 686
 687 /**
 688  * Search an entity by its symbol in a given namespace.
 689  */
 690 static entity_t *get_entity(const symbol_t *const symbol,
 691                             namespace_tag_t namespc)
 692 {
 693         entity_t *entity = symbol->entity;
 694         for (; entity != NULL; entity = entity->base.symbol_next) {
 695                 if ((namespace_tag_t)entity->base.namespc == namespc)
 696                         return entity;
 697         }
 698
 699         return NULL;
 700 }
 701
 702 /* §6.2.3:1 24)  There is only one name space for tags even though three are
 703  * possible. */
 704 static entity_t *get_tag(symbol_t const *const symbol,
 705                          entity_kind_tag_t const kind)
 706 {
 707         entity_t *entity = get_entity(symbol, NAMESPACE_TAG);
 708         if (entity != NULL && (entity_kind_tag_t)entity->kind != kind) {
 709                 errorf(HERE,
 710                                 "'%Y' defined as wrong kind of tag (previous definition %P)",
 711                                 symbol, &entity->base.source_position);
 712                 entity = NULL;
 713         }
 714         return entity;
 715 }
 716
 717 /**
 718  * pushs an entity on the environment stack and links the corresponding symbol
 719  * it.
 720  */
 721 static void stack_push(stack_entry_t **stack_ptr, entity_t *entity)
 722 {
 723         symbol_t           *symbol  = entity->base.symbol;
 724         entity_namespace_t  namespc = entity->base.namespc;
 725         assert(namespc != 0);
 726
 727         /* replace/add entity into entity list of the symbol */
 728         entity_t **anchor;
 729         entity_t  *iter;
 730         for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 731                 iter = *anchor;
 732                 if (iter == NULL)
 733                         break;
 734
 735                 /* replace an entry? */
 736                 if (iter->base.namespc == namespc) {
 737                         entity->base.symbol_next = iter->base.symbol_next;
 738                         break;
 739                 }
 740         }
 741         *anchor = entity;
 742
 743         /* remember old declaration */
 744         stack_entry_t entry;
 745         entry.symbol     = symbol;
 746         entry.old_entity = iter;
 747         entry.namespc    = namespc;
 748         ARR_APP1(stack_entry_t, *stack_ptr, entry);
 749 }
 750
 751 /**
 752  * Push an entity on the environment stack.
 753  */
 754 static void environment_push(entity_t *entity)
 755 {
 756         assert(entity->base.source_position.input_name != NULL);
 757         assert(entity->base.parent_scope != NULL);
 758         stack_push(&environment_stack, entity);
 759 }
 760
 761 /**
 762  * Push a declaration on the global label stack.
 763  *
 764  * @param declaration  the declaration
 765  */
 766 static void label_push(entity_t *label)
 767 {
 768         /* we abuse the parameters scope as parent for the labels */
 769         label->base.parent_scope = &current_function->parameters;
 770         stack_push(&label_stack, label);
 771 }
 772
 773 /**
 774  * pops symbols from the environment stack until @p new_top is the top element
 775  */
 776 static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 777 {
 778         stack_entry_t *stack = *stack_ptr;
 779         size_t         top   = ARR_LEN(stack);
 780         size_t         i;
 781
 782         assert(new_top <= top);
 783         if (new_top == top)
 784                 return;
 785
 786         for (i = top; i > new_top; --i) {
 787                 stack_entry_t *entry = &stack[i - 1];
 788
 789                 entity_t           *old_entity = entry->old_entity;
 790                 symbol_t           *symbol     = entry->symbol;
 791                 entity_namespace_t  namespc    = entry->namespc;
 792
 793                 /* replace with old_entity/remove */
 794                 entity_t **anchor;
 795                 entity_t  *iter;
 796                 for (anchor = &symbol->entity; ; anchor = &iter->base.symbol_next) {
 797                         iter = *anchor;
 798                         assert(iter != NULL);
 799                         /* replace an entry? */
 800                         if (iter->base.namespc == namespc)
 801                                 break;
 802                 }
 803
 804                 /* restore definition from outer scopes (if there was one) */
 805                 if (old_entity != NULL) {
 806                         old_entity->base.symbol_next = iter->base.symbol_next;
 807                         *anchor                      = old_entity;
 808                 } else {
 809                         /* remove entry from list */
 810                         *anchor = iter->base.symbol_next;
 811                 }
 812         }
 813
 814         ARR_SHRINKLEN(*stack_ptr, new_top);
 815 }
 816
 817 /**
 818  * Pop all entries from the environment stack until the new_top
 819  * is reached.
 820  *
 821  * @param new_top  the new stack top
 822  */
 823 static void environment_pop_to(size_t new_top)
 824 {
 825         stack_pop_to(&environment_stack, new_top);
 826 }
 827
 828 /**
 829  * Pop all entries from the global label stack until the new_top
 830  * is reached.
 831  *
 832  * @param new_top  the new stack top
 833  */
 834 static void label_pop_to(size_t new_top)
 835 {
 836         stack_pop_to(&label_stack, new_top);
 837 }
 838
 839 static atomic_type_kind_t get_akind(const type_t *type)
 840 {
 841         assert(type->kind == TYPE_ATOMIC || type->kind == TYPE_COMPLEX
 842                || type->kind == TYPE_IMAGINARY || type->kind == TYPE_ENUM);
 843         return type->atomic.akind;
 844 }
 845
 846 /**
 847  * §6.3.1.1:2  Do integer promotion for a given type.
 848  *
 849  * @param type  the type to promote
 850  * @return the promoted type
 851  */
 852 static type_t *promote_integer(type_t *type)
 853 {
 854         if (get_akind_rank(get_akind(type)) < get_akind_rank(ATOMIC_TYPE_INT))
 855                 type = type_int;
 856
 857         return type;
 858 }
 859
 860 /**
 861  * Check if a given expression represents a null pointer constant.
 862  *
 863  * @param expression  the expression to check
 864  */
 865 static bool is_null_pointer_constant(const expression_t *expression)
 866 {
 867         /* skip void* cast */
 868         if (expression->kind == EXPR_UNARY_CAST) {
 869                 type_t *const type = skip_typeref(expression->base.type);
 870                 if (types_compatible(type, type_void_ptr))
 871                         expression = expression->unary.value;
 872         }
 873
 874         type_t *const type = skip_typeref(expression->base.type);
 875         if (!is_type_integer(type))
 876                 return false;
 877         switch (is_constant_expression(expression)) {
 878                 case EXPR_CLASS_ERROR:    return true;
 879                 case EXPR_CLASS_CONSTANT: return !fold_constant_to_bool(expression);
 880                 default:                  return false;
 881         }
 882 }
 883
 884 /**
 885  * Create an implicit cast expression.
 886  *
 887  * @param expression  the expression to cast
 888  * @param dest_type   the destination type
 889  */
 890 static expression_t *create_implicit_cast(expression_t *expression,
 891                                           type_t *dest_type)
 892 {
 893         type_t *const source_type = expression->base.type;
 894
 895         if (source_type == dest_type)
 896                 return expression;
 897
 898         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
 899         cast->unary.value   = expression;
 900         cast->base.type     = dest_type;
 901         cast->base.implicit = true;
 902
 903         return cast;
 904 }
 905
 906 typedef enum assign_error_t {
 907         ASSIGN_SUCCESS,
 908         ASSIGN_ERROR_INCOMPATIBLE,
 909         ASSIGN_ERROR_POINTER_QUALIFIER_MISSING,
 910         ASSIGN_WARNING_POINTER_INCOMPATIBLE,
 911         ASSIGN_WARNING_POINTER_FROM_INT,
 912         ASSIGN_WARNING_INT_FROM_POINTER
 913 } assign_error_t;
 914
 915 static void report_assign_error(assign_error_t error, type_t *orig_type_left, expression_t const *const right, char const *const context, source_position_t const *const pos)
 916 {
 917         type_t *const orig_type_right = right->base.type;
 918         type_t *const type_left       = skip_typeref(orig_type_left);
 919         type_t *const type_right      = skip_typeref(orig_type_right);
 920
 921         switch (error) {
 922         case ASSIGN_SUCCESS:
 923                 return;
 924         case ASSIGN_ERROR_INCOMPATIBLE:
 925                 errorf(pos, "destination type '%T' in %s is incompatible with type '%T'", orig_type_left, context, orig_type_right);
 926                 return;
 927
 928         case ASSIGN_ERROR_POINTER_QUALIFIER_MISSING: {
 929                 type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
 930                 type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 931
 932                 /* the left type has all qualifiers from the right type */
 933                 unsigned missing_qualifiers = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 934                 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);
 935                 return;
 936         }
 937
 938         case ASSIGN_WARNING_POINTER_INCOMPATIBLE:
 939                 warningf(WARN_OTHER, pos, "destination type '%T' in %s is incompatible with '%E' of type '%T'", orig_type_left, context, right, orig_type_right);
 940                 return;
 941
 942         case ASSIGN_WARNING_POINTER_FROM_INT:
 943                 warningf(WARN_OTHER, pos, "%s makes pointer '%T' from integer '%T' without a cast", context, orig_type_left, orig_type_right);
 944                 return;
 945
 946         case ASSIGN_WARNING_INT_FROM_POINTER:
 947                 warningf(WARN_OTHER, pos, "%s makes integer '%T' from pointer '%T' without a cast", context, orig_type_left, orig_type_right);
 948                 return;
 949
 950         default:
 951                 panic("invalid error value");
 952         }
 953 }
 954
 955 /** Implements the rules from §6.5.16.1 */
 956 static assign_error_t semantic_assign(type_t *orig_type_left,
 957                                       const expression_t *const right)
 958 {
 959         type_t *const orig_type_right = right->base.type;
 960         type_t *const type_left       = skip_typeref(orig_type_left);
 961         type_t *const type_right      = skip_typeref(orig_type_right);
 962
 963         if (is_type_pointer(type_left)) {
 964                 if (is_null_pointer_constant(right)) {
 965                         return ASSIGN_SUCCESS;
 966                 } else if (is_type_pointer(type_right)) {
 967                         type_t *points_to_left
 968                                 = skip_typeref(type_left->pointer.points_to);
 969                         type_t *points_to_right
 970                                 = skip_typeref(type_right->pointer.points_to);
 971                         assign_error_t res = ASSIGN_SUCCESS;
 972
 973                         /* the left type has all qualifiers from the right type */
 974                         unsigned missing_qualifiers
 975                                 = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
 976                         if (missing_qualifiers != 0) {
 977                                 res = ASSIGN_ERROR_POINTER_QUALIFIER_MISSING;
 978                         }
 979
 980                         points_to_left  = get_unqualified_type(points_to_left);
 981                         points_to_right = get_unqualified_type(points_to_right);
 982
 983                         if (is_type_void(points_to_left))
 984                                 return res;
 985
 986                         if (is_type_void(points_to_right)) {
 987                                 /* ISO/IEC 14882:1998(E) §C.1.2:6 */
 988                                 return c_mode & _CXX ? ASSIGN_ERROR_INCOMPATIBLE : res;
 989                         }
 990
 991                         if (!types_compatible(points_to_left, points_to_right)) {
 992                                 return ASSIGN_WARNING_POINTER_INCOMPATIBLE;
 993                         }
 994
 995                         return res;
 996                 } else if (is_type_integer(type_right)) {
 997                         return ASSIGN_WARNING_POINTER_FROM_INT;
 998                 }
 999         } else if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
1000                         (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
1001                                 && is_type_pointer(type_right))) {
1002                 return ASSIGN_SUCCESS;
1003         } else if (is_type_compound(type_left) && is_type_compound(type_right)) {
1004                 type_t *const unqual_type_left  = get_unqualified_type(type_left);
1005                 type_t *const unqual_type_right = get_unqualified_type(type_right);
1006                 if (types_compatible(unqual_type_left, unqual_type_right)) {
1007                         return ASSIGN_SUCCESS;
1008                 }
1009         } else if (is_type_integer(type_left) && is_type_pointer(type_right)) {
1010                 return ASSIGN_WARNING_INT_FROM_POINTER;
1011         }
1012
1013         if (!is_type_valid(type_left) || !is_type_valid(type_right))
1014                 return ASSIGN_SUCCESS;
1015
1016         return ASSIGN_ERROR_INCOMPATIBLE;
1017 }
1018
1019 static expression_t *parse_constant_expression(void)
1020 {
1021         expression_t *result = parse_subexpression(PREC_CONDITIONAL);
1022
1023         if (is_constant_expression(result) == EXPR_CLASS_VARIABLE) {
1024                 errorf(&result->base.source_position,
1025                        "expression '%E' is not constant", result);
1026         }
1027
1028         return result;
1029 }
1030
1031 static expression_t *parse_assignment_expression(void)
1032 {
1033         return parse_subexpression(PREC_ASSIGNMENT);
1034 }
1035
1036 static void append_string(string_t const *const s)
1037 {
1038         /* FIXME Using the ast_obstack is a hack.  Using the symbol_obstack is not
1039          * possible, because other tokens are grown there alongside. */
1040         obstack_grow(&ast_obstack, s->begin, s->size);
1041 }
1042
1043 static string_t finish_string(void)
1044 {
1045         obstack_1grow(&ast_obstack, '\0');
1046         size_t      const size   = obstack_object_size(&ast_obstack) - 1;
1047         char const *const string = obstack_finish(&ast_obstack);
1048         return (string_t){ string, size };
1049 }
1050
1051 static string_t concat_string_literals(string_encoding_t *const out_enc)
1052 {
1053         assert(token.kind == T_STRING_LITERAL);
1054
1055         string_t          result;
1056         string_encoding_t enc = token.string.encoding;
1057         if (look_ahead(1)->kind == T_STRING_LITERAL) {
1058                 append_string(&token.string.string);
1059                 eat(T_STRING_LITERAL);
1060                 warningf(WARN_TRADITIONAL, HERE, "traditional C rejects string constant concatenation");
1061                 do {
1062                         if (token.string.encoding != STRING_ENCODING_CHAR) {
1063                                 enc = token.string.encoding;
1064                         }
1065                         append_string(&token.string.string);
1066                         eat(T_STRING_LITERAL);
1067                 } while (token.kind == T_STRING_LITERAL);
1068                 result = finish_string();
1069         } else {
1070                 result = token.string.string;
1071                 eat(T_STRING_LITERAL);
1072         }
1073
1074         *out_enc = enc;
1075         return result;
1076 }
1077
1078 static string_t parse_string_literals(char const *const context)
1079 {
1080         if (!skip_till(T_STRING_LITERAL, context))
1081                 return (string_t){ "", 0 };
1082
1083         string_encoding_t       enc;
1084         source_position_t const pos = *HERE;
1085         string_t          const res = concat_string_literals(&enc);
1086
1087         if (enc != STRING_ENCODING_CHAR) {
1088                 errorf(&pos, "expected plain string literal, got wide string literal");
1089         }
1090
1091         return res;
1092 }
1093
1094 static attribute_t *allocate_attribute_zero(attribute_kind_t kind)
1095 {
1096         attribute_t *attribute = allocate_ast_zero(sizeof(*attribute));
1097         attribute->kind            = kind;
1098         attribute->source_position = *HERE;
1099         return attribute;
1100 }
1101
1102 /**
1103  * Parse (gcc) attribute argument. From gcc comments in gcc source:
1104  *
1105  *  attribute:
1106  *    __attribute__ ( ( attribute-list ) )
1107  *
1108  *  attribute-list:
1109  *    attrib
1110  *    attribute_list , attrib
1111  *
1112  *  attrib:
1113  *    empty
1114  *    any-word
1115  *    any-word ( identifier )
1116  *    any-word ( identifier , nonempty-expr-list )
1117  *    any-word ( expr-list )
1118  *
1119  *  where the "identifier" must not be declared as a type, and
1120  *  "any-word" may be any identifier (including one declared as a
1121  *  type), a reserved word storage class specifier, type specifier or
1122  *  type qualifier.  ??? This still leaves out most reserved keywords
1123  *  (following the old parser), shouldn't we include them, and why not
1124  *  allow identifiers declared as types to start the arguments?
1125  *
1126  *  Matze: this all looks confusing and little systematic, so we're even less
1127  *  strict and parse any list of things which are identifiers or
1128  *  (assignment-)expressions.
1129  */
1130 static attribute_argument_t *parse_attribute_arguments(void)
1131 {
1132         attribute_argument_t  *first  = NULL;
1133         attribute_argument_t **anchor = &first;
1134         if (token.kind != ')') do {
1135                 attribute_argument_t *argument = allocate_ast_zero(sizeof(*argument));
1136
1137                 /* is it an identifier */
1138                 if (token.kind == T_IDENTIFIER
1139                                 && (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
1140                         argument->kind     = ATTRIBUTE_ARGUMENT_SYMBOL;
1141                         argument->v.symbol = token.base.symbol;
1142                         eat(T_IDENTIFIER);
1143                 } else {
1144                         /* must be an expression */
1145                         expression_t *expression = parse_assignment_expression();
1146
1147                         argument->kind         = ATTRIBUTE_ARGUMENT_EXPRESSION;
1148                         argument->v.expression = expression;
1149                 }
1150
1151                 /* append argument */
1152                 *anchor = argument;
1153                 anchor  = &argument->next;
1154         } while (next_if(','));
1155         expect(')');
1156         return first;
1157 }
1158
1159 static attribute_t *parse_attribute_asm(void)
1160 {
1161         attribute_t *attribute = allocate_attribute_zero(ATTRIBUTE_GNU_ASM);
1162         eat(T_asm);
1163         expect('(');
1164         attribute->a.arguments = parse_attribute_arguments();
1165         return attribute;
1166 }
1167
1168 static attribute_t *parse_attribute_gnu_single(void)
1169 {
1170         /* parse "any-word" */
1171         symbol_t *const symbol = token.base.symbol;
1172         if (symbol == NULL) {
1173                 parse_error_expected("while parsing attribute((", T_IDENTIFIER, NULL);
1174                 return NULL;
1175         }
1176
1177         attribute_kind_t  kind;
1178         char const *const name = symbol->string;
1179         for (kind = ATTRIBUTE_GNU_FIRST;; ++kind) {
1180                 if (kind > ATTRIBUTE_GNU_LAST) {
1181                         warningf(WARN_ATTRIBUTE, HERE, "unknown attribute '%s' ignored", name);
1182                         /* TODO: we should still save the attribute in the list... */
1183                         kind = ATTRIBUTE_UNKNOWN;
1184                         break;
1185                 }
1186
1187                 const char *attribute_name = get_attribute_name(kind);
1188                 if (attribute_name != NULL && streq_underscore(attribute_name, name))
1189                         break;
1190         }
1191
1192         attribute_t *attribute = allocate_attribute_zero(kind);
1193         next_token();
1194
1195         /* parse arguments */
1196         if (next_if('('))
1197                 attribute->a.arguments = parse_attribute_arguments();
1198
1199         return attribute;
1200 }
1201
1202 static attribute_t *parse_attribute_gnu(void)
1203 {
1204         attribute_t  *first  = NULL;
1205         attribute_t **anchor = &first;
1206
1207         eat(T___attribute__);
1208         add_anchor_token(')');
1209         add_anchor_token(',');
1210         expect('(');
1211         expect('(');
1212
1213         if (token.kind != ')') do {
1214                 attribute_t *attribute = parse_attribute_gnu_single();
1215                 if (attribute) {
1216                         *anchor = attribute;
1217                         anchor  = &attribute->next;
1218                 }
1219         } while (next_if(','));
1220         rem_anchor_token(',');
1221         rem_anchor_token(')');
1222
1223         expect(')');
1224         expect(')');
1225         return first;
1226 }
1227
1228 /** Parse attributes. */
1229 static attribute_t *parse_attributes(attribute_t *first)
1230 {
1231         attribute_t **anchor = &first;
1232         for (;;) {
1233                 while (*anchor != NULL)
1234                         anchor = &(*anchor)->next;
1235
1236                 attribute_t *attribute;
1237                 switch (token.kind) {
1238                 case T___attribute__:
1239                         attribute = parse_attribute_gnu();
1240                         if (attribute == NULL)
1241                                 continue;
1242                         break;
1243
1244                 case T_asm:
1245                         attribute = parse_attribute_asm();
1246                         break;
1247
1248                 case T_cdecl:
1249                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_CDECL);
1250                         eat(T_cdecl);
1251                         break;
1252
1253                 case T__fastcall:
1254                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FASTCALL);
1255                         eat(T__fastcall);
1256                         break;
1257
1258                 case T__forceinline:
1259                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_FORCEINLINE);
1260                         eat(T__forceinline);
1261                         break;
1262
1263                 case T__stdcall:
1264                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_STDCALL);
1265                         eat(T__stdcall);
1266                         break;
1267
1268                 case T___thiscall:
1269                         /* TODO record modifier */
1270                         warningf(WARN_OTHER, HERE, "Ignoring declaration modifier %K", &token);
1271                         attribute = allocate_attribute_zero(ATTRIBUTE_MS_THISCALL);
1272                         eat(T___thiscall);
1273                         break;
1274
1275                 default:
1276                         return first;
1277                 }
1278
1279                 *anchor = attribute;
1280                 anchor  = &attribute->next;
1281         }
1282 }
1283
1284 static void mark_vars_read(expression_t *expr, entity_t *lhs_ent);
1285
1286 static entity_t *determine_lhs_ent(expression_t *const expr,
1287                                    entity_t *lhs_ent)
1288 {
1289         switch (expr->kind) {
1290                 case EXPR_REFERENCE: {
1291                         entity_t *const entity = expr->reference.entity;
1292                         /* we should only find variables as lvalues... */
1293                         if (entity->base.kind != ENTITY_VARIABLE
1294                                         && entity->base.kind != ENTITY_PARAMETER)
1295                                 return NULL;
1296
1297                         return entity;
1298                 }
1299
1300                 case EXPR_ARRAY_ACCESS: {
1301                         expression_t *const ref = expr->array_access.array_ref;
1302                         entity_t     *      ent = NULL;
1303                         if (is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1304                                 ent     = determine_lhs_ent(ref, lhs_ent);
1305                                 lhs_ent = ent;
1306                         } else {
1307                                 mark_vars_read(ref, lhs_ent);
1308                         }
1309                         mark_vars_read(expr->array_access.index, lhs_ent);
1310                         return ent;
1311                 }
1312
1313                 case EXPR_SELECT: {
1314                         mark_vars_read(expr->select.compound, lhs_ent);
1315                         if (is_type_compound(skip_typeref(expr->base.type)))
1316                                 return determine_lhs_ent(expr->select.compound, lhs_ent);
1317                         return NULL;
1318                 }
1319
1320                 case EXPR_UNARY_DEREFERENCE: {
1321                         expression_t *const val = expr->unary.value;
1322                         if (val->kind == EXPR_UNARY_TAKE_ADDRESS) {
1323                                 /* *&x is a NOP */
1324                                 return determine_lhs_ent(val->unary.value, lhs_ent);
1325                         } else {
1326                                 mark_vars_read(val, NULL);
1327                                 return NULL;
1328                         }
1329                 }
1330
1331                 default:
1332                         mark_vars_read(expr, NULL);
1333                         return NULL;
1334         }
1335 }
1336
1337 #define ENT_ANY ((entity_t*)-1)
1338
1339 /**
1340  * Mark declarations, which are read.  This is used to detect variables, which
1341  * are never read.
1342  * Example:
1343  * x = x + 1;
1344  *   x is not marked as "read", because it is only read to calculate its own new
1345  *   value.
1346  *
1347  * x += y; y += x;
1348  *   x and y are not detected as "not read", because multiple variables are
1349  *   involved.
1350  */
1351 static void mark_vars_read(expression_t *const expr, entity_t *lhs_ent)
1352 {
1353         switch (expr->kind) {
1354                 case EXPR_REFERENCE: {
1355                         entity_t *const entity = expr->reference.entity;
1356                         if (entity->kind != ENTITY_VARIABLE
1357                                         && entity->kind != ENTITY_PARAMETER)
1358                                 return;
1359
1360                         if (lhs_ent != entity && lhs_ent != ENT_ANY) {
1361                                 entity->variable.read = true;
1362                         }
1363                         return;
1364                 }
1365
1366                 case EXPR_CALL:
1367                         // TODO respect pure/const
1368                         mark_vars_read(expr->call.function, NULL);
1369                         for (call_argument_t *arg = expr->call.arguments; arg != NULL; arg = arg->next) {
1370                                 mark_vars_read(arg->expression, NULL);
1371                         }
1372                         return;
1373
1374                 case EXPR_CONDITIONAL:
1375                         // TODO lhs_decl should depend on whether true/false have an effect
1376                         mark_vars_read(expr->conditional.condition, NULL);
1377                         if (expr->conditional.true_expression != NULL)
1378                                 mark_vars_read(expr->conditional.true_expression, lhs_ent);
1379                         mark_vars_read(expr->conditional.false_expression, lhs_ent);
1380                         return;
1381
1382                 case EXPR_SELECT:
1383                         if (lhs_ent == ENT_ANY
1384                                         && !is_type_compound(skip_typeref(expr->base.type)))
1385                                 lhs_ent = NULL;
1386                         mark_vars_read(expr->select.compound, lhs_ent);
1387                         return;
1388
1389                 case EXPR_ARRAY_ACCESS: {
1390                         mark_vars_read(expr->array_access.index, lhs_ent);
1391                         expression_t *const ref = expr->array_access.array_ref;
1392                         if (!is_type_array(skip_typeref(revert_automatic_type_conversion(ref)))) {
1393                                 if (lhs_ent == ENT_ANY)
1394                                         lhs_ent = NULL;
1395                         }
1396                         mark_vars_read(ref, lhs_ent);
1397                         return;
1398                 }
1399
1400                 case EXPR_VA_ARG:
1401                         mark_vars_read(expr->va_arge.ap, lhs_ent);
1402                         return;
1403
1404                 case EXPR_VA_COPY:
1405                         mark_vars_read(expr->va_copye.src, lhs_ent);
1406                         return;
1407
1408                 case EXPR_UNARY_CAST:
1409                         /* Special case: Use void cast to mark a variable as "read" */
1410                         if (is_type_void(skip_typeref(expr->base.type)))
1411                                 lhs_ent = NULL;
1412                         goto unary;
1413
1414
1415                 case EXPR_UNARY_THROW:
1416                         if (expr->unary.value == NULL)
1417                                 return;
1418                         /* FALLTHROUGH */
1419                 case EXPR_UNARY_DEREFERENCE:
1420                 case EXPR_UNARY_DELETE:
1421                 case EXPR_UNARY_DELETE_ARRAY:
1422                         if (lhs_ent == ENT_ANY)
1423                                 lhs_ent = NULL;
1424                         goto unary;
1425
1426                 case EXPR_UNARY_NEGATE:
1427                 case EXPR_UNARY_PLUS:
1428                 case EXPR_UNARY_BITWISE_NEGATE:
1429                 case EXPR_UNARY_NOT:
1430                 case EXPR_UNARY_TAKE_ADDRESS:
1431                 case EXPR_UNARY_POSTFIX_INCREMENT:
1432                 case EXPR_UNARY_POSTFIX_DECREMENT:
1433                 case EXPR_UNARY_PREFIX_INCREMENT:
1434                 case EXPR_UNARY_PREFIX_DECREMENT:
1435                 case EXPR_UNARY_ASSUME:
1436 unary:
1437                         mark_vars_read(expr->unary.value, lhs_ent);
1438                         return;
1439
1440                 case EXPR_BINARY_ADD:
1441                 case EXPR_BINARY_SUB:
1442                 case EXPR_BINARY_MUL:
1443                 case EXPR_BINARY_DIV:
1444                 case EXPR_BINARY_MOD:
1445                 case EXPR_BINARY_EQUAL:
1446                 case EXPR_BINARY_NOTEQUAL:
1447                 case EXPR_BINARY_LESS:
1448                 case EXPR_BINARY_LESSEQUAL:
1449                 case EXPR_BINARY_GREATER:
1450                 case EXPR_BINARY_GREATEREQUAL:
1451                 case EXPR_BINARY_BITWISE_AND:
1452                 case EXPR_BINARY_BITWISE_OR:
1453                 case EXPR_BINARY_BITWISE_XOR:
1454                 case EXPR_BINARY_LOGICAL_AND:
1455                 case EXPR_BINARY_LOGICAL_OR:
1456                 case EXPR_BINARY_SHIFTLEFT:
1457                 case EXPR_BINARY_SHIFTRIGHT:
1458                 case EXPR_BINARY_COMMA:
1459                 case EXPR_BINARY_ISGREATER:
1460                 case EXPR_BINARY_ISGREATEREQUAL:
1461                 case EXPR_BINARY_ISLESS:
1462                 case EXPR_BINARY_ISLESSEQUAL:
1463                 case EXPR_BINARY_ISLESSGREATER:
1464                 case EXPR_BINARY_ISUNORDERED:
1465                         mark_vars_read(expr->binary.left,  lhs_ent);
1466                         mark_vars_read(expr->binary.right, lhs_ent);
1467                         return;
1468
1469                 case EXPR_BINARY_ASSIGN:
1470                 case EXPR_BINARY_MUL_ASSIGN:
1471                 case EXPR_BINARY_DIV_ASSIGN:
1472                 case EXPR_BINARY_MOD_ASSIGN:
1473                 case EXPR_BINARY_ADD_ASSIGN:
1474                 case EXPR_BINARY_SUB_ASSIGN:
1475                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:
1476                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:
1477                 case EXPR_BINARY_BITWISE_AND_ASSIGN:
1478                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:
1479                 case EXPR_BINARY_BITWISE_OR_ASSIGN: {
1480                         if (lhs_ent == ENT_ANY)
1481                                 lhs_ent = NULL;
1482                         lhs_ent = determine_lhs_ent(expr->binary.left, lhs_ent);
1483                         mark_vars_read(expr->binary.right, lhs_ent);
1484                         return;
1485                 }
1486
1487                 case EXPR_VA_START:
1488                         determine_lhs_ent(expr->va_starte.ap, lhs_ent);
1489                         return;
1490
1491                 case EXPR_LITERAL_CASES:
1492                 case EXPR_LITERAL_CHARACTER:
1493                 case EXPR_LITERAL_WIDE_CHARACTER:
1494                 case EXPR_ERROR:
1495                 case EXPR_STRING_LITERAL:
1496                 case EXPR_COMPOUND_LITERAL: // TODO init?
1497                 case EXPR_SIZEOF:
1498                 case EXPR_CLASSIFY_TYPE:
1499                 case EXPR_ALIGNOF:
1500                 case EXPR_FUNCNAME:
1501                 case EXPR_BUILTIN_CONSTANT_P:
1502                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
1503                 case EXPR_OFFSETOF:
1504                 case EXPR_STATEMENT: // TODO
1505                 case EXPR_LABEL_ADDRESS:
1506                 case EXPR_ENUM_CONSTANT:
1507                         return;
1508         }
1509
1510         panic("unhandled expression");
1511 }
1512
1513 static designator_t *parse_designation(void)
1514 {
1515         designator_t  *result = NULL;
1516         designator_t **anchor = &result;
1517
1518         for (;;) {
1519                 designator_t *designator;
1520                 switch (token.kind) {
1521                 case '[':
1522                         designator = allocate_ast_zero(sizeof(designator[0]));
1523                         designator->source_position = *HERE;
1524                         eat('[');
1525                         add_anchor_token(']');
1526                         designator->array_index = parse_constant_expression();
1527                         rem_anchor_token(']');
1528                         expect(']');
1529                         break;
1530                 case '.':
1531                         designator = allocate_ast_zero(sizeof(designator[0]));
1532                         designator->source_position = *HERE;
1533                         eat('.');
1534                         designator->symbol = expect_identifier("while parsing designator", NULL);
1535                         if (!designator->symbol)
1536                                 return NULL;
1537                         break;
1538                 default:
1539                         expect('=');
1540                         return result;
1541                 }
1542
1543                 assert(designator != NULL);
1544                 *anchor = designator;
1545                 anchor  = &designator->next;
1546         }
1547 }
1548
1549 static initializer_t *initializer_from_string(array_type_t *const type,
1550                                               const string_t *const string)
1551 {
1552         /* TODO: check len vs. size of array type */
1553         (void) type;
1554
1555         initializer_t *initializer = allocate_initializer_zero(INITIALIZER_STRING);
1556         initializer->string.string = *string;
1557
1558         return initializer;
1559 }
1560
1561 static initializer_t *initializer_from_wide_string(array_type_t *const type,
1562                                                    const string_t *const string)
1563 {
1564         /* TODO: check len vs. size of array type */
1565         (void) type;
1566
1567         initializer_t *const initializer =
1568                 allocate_initializer_zero(INITIALIZER_WIDE_STRING);
1569         initializer->wide_string.string = *string;
1570
1571         return initializer;
1572 }
1573
1574 /**
1575  * Build an initializer from a given expression.
1576  */
1577 static initializer_t *initializer_from_expression(type_t *orig_type,
1578                                                   expression_t *expression)
1579 {
1580         /* TODO check that expression is a constant expression */
1581
1582         /* §6.7.8.14/15 char array may be initialized by string literals */
1583         type_t *type           = skip_typeref(orig_type);
1584         type_t *expr_type_orig = expression->base.type;
1585         type_t *expr_type      = skip_typeref(expr_type_orig);
1586
1587         if (is_type_array(type) && expr_type->kind == TYPE_POINTER) {
1588                 array_type_t *const array_type   = &type->array;
1589                 type_t       *const element_type = skip_typeref(array_type->element_type);
1590
1591                 if (element_type->kind == TYPE_ATOMIC && expression->kind == EXPR_STRING_LITERAL) {
1592                         switch (expression->string_literal.encoding) {
1593                         case STRING_ENCODING_CHAR: {
1594                                 atomic_type_kind_t const akind = element_type->atomic.akind;
1595                                 if (akind == ATOMIC_TYPE_CHAR
1596                                                 || akind == ATOMIC_TYPE_SCHAR
1597                                                 || akind == ATOMIC_TYPE_UCHAR) {
1598                                         return initializer_from_string(array_type,
1599                                                         &expression->string_literal.value);
1600                                 }
1601                                 break;
1602                         }
1603
1604                         case STRING_ENCODING_WIDE: {
1605                                 type_t *bare_wchar_type = skip_typeref(type_wchar_t);
1606                                 if (get_unqualified_type(element_type) == bare_wchar_type) {
1607                                         return initializer_from_wide_string(array_type,
1608                                                         &expression->string_literal.value);
1609                                 }
1610                                 break;
1611                         }
1612                         }
1613                 }
1614         }
1615
1616         assign_error_t error = semantic_assign(type, expression);
1617         if (error == ASSIGN_ERROR_INCOMPATIBLE)
1618                 return NULL;
1619         report_assign_error(error, type, expression, "initializer",
1620                             &expression->base.source_position);
1621
1622         initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
1623         result->value.value = create_implicit_cast(expression, type);
1624
1625         return result;
1626 }
1627
1628 /**
1629  * Parses an scalar initializer.
1630  *
1631  * §6.7.8.11; eat {} without warning
1632  */
1633 static initializer_t *parse_scalar_initializer(type_t *type,
1634                                                bool must_be_constant)
1635 {
1636         /* there might be extra {} hierarchies */
1637         int braces = 0;
1638         if (token.kind == '{') {
1639                 warningf(WARN_OTHER, HERE, "extra curly braces around scalar initializer");
1640                 do {
1641                         eat('{');
1642                         ++braces;
1643                 } while (token.kind == '{');
1644         }
1645
1646         expression_t *expression = parse_assignment_expression();
1647         mark_vars_read(expression, NULL);
1648         if (must_be_constant && !is_linker_constant(expression)) {
1649                 errorf(&expression->base.source_position,
1650                        "initialisation expression '%E' is not constant",
1651                        expression);
1652         }
1653
1654         initializer_t *initializer = initializer_from_expression(type, expression);
1655
1656         if (initializer == NULL) {
1657                 errorf(&expression->base.source_position,
1658                        "expression '%E' (type '%T') doesn't match expected type '%T'",
1659                        expression, expression->base.type, type);
1660                 /* TODO */
1661                 return NULL;
1662         }
1663
1664         bool additional_warning_displayed = false;
1665         while (braces > 0) {
1666                 next_if(',');
1667                 if (token.kind != '}') {
1668                         if (!additional_warning_displayed) {
1669                                 warningf(WARN_OTHER, HERE, "additional elements in scalar initializer");
1670                                 additional_warning_displayed = true;
1671                         }
1672                 }
1673                 eat_block();
1674                 braces--;
1675         }
1676
1677         return initializer;
1678 }
1679
1680 /**
1681  * An entry in the type path.
1682  */
1683 typedef struct type_path_entry_t type_path_entry_t;
1684 struct type_path_entry_t {
1685         type_t *type;       /**< the upper top type. restored to path->top_tye if this entry is popped. */
1686         union {
1687                 size_t         index;          /**< For array types: the current index. */
1688                 declaration_t *compound_entry; /**< For compound types: the current declaration. */
1689         } v;
1690 };
1691
1692 /**
1693  * A type path expression a position inside compound or array types.
1694  */
1695 typedef struct type_path_t type_path_t;
1696 struct type_path_t {
1697         type_path_entry_t *path;         /**< An flexible array containing the current path. */
1698         type_t            *top_type;     /**< type of the element the path points */
1699         size_t             max_index;    /**< largest index in outermost array */
1700 };
1701
1702 /**
1703  * Prints a type path for debugging.
1704  */
1705 static __attribute__((unused)) void debug_print_type_path(
1706                 const type_path_t *path)
1707 {
1708         size_t len = ARR_LEN(path->path);
1709
1710         for (size_t i = 0; i < len; ++i) {
1711                 const type_path_entry_t *entry = & path->path[i];
1712
1713                 type_t *type = skip_typeref(entry->type);
1714                 if (is_type_compound(type)) {
1715                         /* in gcc mode structs can have no members */
1716                         if (entry->v.compound_entry == NULL) {
1717                                 assert(i == len-1);
1718                                 continue;
1719                         }
1720                         fprintf(stderr, ".%s",
1721                                 entry->v.compound_entry->base.symbol->string);
1722                 } else if (is_type_array(type)) {
1723                         fprintf(stderr, "[%u]", (unsigned) entry->v.index);
1724                 } else {
1725                         fprintf(stderr, "-INVALID-");
1726                 }
1727         }
1728         if (path->top_type != NULL) {
1729                 fprintf(stderr, "  (");
1730                 print_type(path->top_type);
1731                 fprintf(stderr, ")");
1732         }
1733 }
1734
1735 /**
1736  * Return the top type path entry, ie. in a path
1737  * (type).a.b returns the b.
1738  */
1739 static type_path_entry_t *get_type_path_top(const type_path_t *path)
1740 {
1741         size_t len = ARR_LEN(path->path);
1742         assert(len > 0);
1743         return &path->path[len-1];
1744 }
1745
1746 /**
1747  * Enlarge the type path by an (empty) element.
1748  */
1749 static type_path_entry_t *append_to_type_path(type_path_t *path)
1750 {
1751         size_t len = ARR_LEN(path->path);
1752         ARR_RESIZE(type_path_entry_t, path->path, len+1);
1753
1754         type_path_entry_t *result = & path->path[len];
1755         memset(result, 0, sizeof(result[0]));
1756         return result;
1757 }
1758
1759 /**
1760  * Descending into a sub-type. Enter the scope of the current top_type.
1761  */
1762 static void descend_into_subtype(type_path_t *path)
1763 {
1764         type_t *orig_top_type = path->top_type;
1765         type_t *top_type      = skip_typeref(orig_top_type);
1766
1767         type_path_entry_t *top = append_to_type_path(path);
1768         top->type              = top_type;
1769
1770         if (is_type_compound(top_type)) {
1771                 compound_t *const compound = top_type->compound.compound;
1772                 entity_t   *const entry    = skip_unnamed_bitfields(compound->members.entities);
1773
1774                 if (entry != NULL) {
1775                         top->v.compound_entry = &entry->declaration;
1776                         path->top_type = entry->declaration.type;
1777                 } else {
1778                         path->top_type = NULL;
1779                 }
1780         } else if (is_type_array(top_type)) {
1781                 top->v.index   = 0;
1782                 path->top_type = top_type->array.element_type;
1783         } else {
1784                 assert(!is_type_valid(top_type));
1785         }
1786 }
1787
1788 /**
1789  * Pop an entry from the given type path, ie. returning from
1790  * (type).a.b to (type).a
1791  */
1792 static void ascend_from_subtype(type_path_t *path)
1793 {
1794         type_path_entry_t *top = get_type_path_top(path);
1795
1796         path->top_type = top->type;
1797
1798         size_t len = ARR_LEN(path->path);
1799         ARR_RESIZE(type_path_entry_t, path->path, len-1);
1800 }
1801
1802 /**
1803  * Pop entries from the given type path until the given
1804  * path level is reached.
1805  */
1806 static void ascend_to(type_path_t *path, size_t top_path_level)
1807 {
1808         size_t len = ARR_LEN(path->path);
1809
1810         while (len > top_path_level) {
1811                 ascend_from_subtype(path);
1812                 len = ARR_LEN(path->path);
1813         }
1814 }
1815
1816 static bool walk_designator(type_path_t *path, const designator_t *designator,
1817                             bool used_in_offsetof)
1818 {
1819         for (; designator != NULL; designator = designator->next) {
1820                 type_path_entry_t *top       = get_type_path_top(path);
1821                 type_t            *orig_type = top->type;
1822
1823                 type_t *type = skip_typeref(orig_type);
1824
1825                 if (designator->symbol != NULL) {
1826                         symbol_t *symbol = designator->symbol;
1827                         if (!is_type_compound(type)) {
1828                                 if (is_type_valid(type)) {
1829                                         errorf(&designator->source_position,
1830                                                "'.%Y' designator used for non-compound type '%T'",
1831                                                symbol, orig_type);
1832                                 }
1833
1834                                 top->type             = type_error_type;
1835                                 top->v.compound_entry = NULL;
1836                                 orig_type             = type_error_type;
1837                         } else {
1838                                 compound_t *compound = type->compound.compound;
1839                                 entity_t   *iter     = compound->members.entities;
1840                                 for (; iter != NULL; iter = iter->base.next) {
1841                                         if (iter->base.symbol == symbol) {
1842                                                 break;
1843                                         }
1844                                 }
1845                                 if (iter == NULL) {
1846                                         errorf(&designator->source_position,
1847                                                "'%T' has no member named '%Y'", orig_type, symbol);
1848                                         return false;
1849                                 }
1850                                 assert(iter->kind == ENTITY_COMPOUND_MEMBER);
1851                                 if (used_in_offsetof && iter->compound_member.bitfield) {
1852                                         errorf(&designator->source_position,
1853                                                    "offsetof designator '%Y' must not specify bitfield",
1854                                                    symbol);
1855                                         return false;
1856                                 }
1857
1858                                 top->type             = orig_type;
1859                                 top->v.compound_entry = &iter->declaration;
1860                                 orig_type             = iter->declaration.type;
1861                         }
1862                 } else {
1863                         expression_t *array_index = designator->array_index;
1864                         if (is_constant_expression(array_index) != EXPR_CLASS_CONSTANT)
1865                                 return true;
1866
1867                         if (!is_type_array(type)) {
1868                                 if (is_type_valid(type)) {
1869                                         errorf(&designator->source_position,
1870                                                "[%E] designator used for non-array type '%T'",
1871                                                array_index, orig_type);
1872                                 }
1873                                 return false;
1874                         }
1875
1876                         long index = fold_constant_to_int(array_index);
1877                         if (!used_in_offsetof) {
1878                                 if (index < 0) {
1879                                         errorf(&designator->source_position,
1880                                                "array index [%E] must be positive", array_index);
1881                                 } else if (type->array.size_constant) {
1882                                         long array_size = type->array.size;
1883                                         if (index >= array_size) {
1884                                                 errorf(&designator->source_position,
1885                                                        "designator [%E] (%d) exceeds array size %d",
1886                                                        array_index, index, array_size);
1887                                         }
1888                                 }
1889                         }
1890
1891                         top->type    = orig_type;
1892                         top->v.index = (size_t) index;
1893                         orig_type    = type->array.element_type;
1894                 }
1895                 path->top_type = orig_type;
1896
1897                 if (designator->next != NULL) {
1898                         descend_into_subtype(path);
1899                 }
1900         }
1901         return true;
1902 }
1903
1904 static void advance_current_object(type_path_t *path, size_t top_path_level)
1905 {
1906         type_path_entry_t *top = get_type_path_top(path);
1907
1908         type_t *type = skip_typeref(top->type);
1909         if (is_type_union(type)) {
1910                 /* in unions only the first element is initialized */
1911                 top->v.compound_entry = NULL;
1912         } else if (is_type_struct(type)) {
1913                 declaration_t *entry = top->v.compound_entry;
1914
1915                 entity_t *const next_entity = skip_unnamed_bitfields(entry->base.next);
1916                 if (next_entity != NULL) {
1917                         assert(is_declaration(next_entity));
1918                         entry = &next_entity->declaration;
1919                 } else {
1920                         entry = NULL;
1921                 }
1922
1923                 top->v.compound_entry = entry;
1924                 if (entry != NULL) {
1925                         path->top_type = entry->type;
1926                         return;
1927                 }
1928         } else if (is_type_array(type)) {
1929                 assert(is_type_array(type));
1930
1931                 top->v.index++;
1932
1933                 if (!type->array.size_constant || top->v.index < type->array.size) {
1934                         return;
1935                 }
1936         } else {
1937                 assert(!is_type_valid(type));
1938                 return;
1939         }
1940
1941         /* we're past the last member of the current sub-aggregate, try if we
1942          * can ascend in the type hierarchy and continue with another subobject */
1943         size_t len = ARR_LEN(path->path);
1944
1945         if (len > top_path_level) {
1946                 ascend_from_subtype(path);
1947                 advance_current_object(path, top_path_level);
1948         } else {
1949                 path->top_type = NULL;
1950         }
1951 }
1952
1953 /**
1954  * skip any {...} blocks until a closing bracket is reached.
1955  */
1956 static void skip_initializers(void)
1957 {
1958         next_if('{');
1959
1960         while (token.kind != '}') {
1961                 if (token.kind == T_EOF)
1962                         return;
1963                 if (token.kind == '{') {
1964                         eat_block();
1965                         continue;
1966                 }
1967                 next_token();
1968         }
1969 }
1970
1971 static initializer_t *create_empty_initializer(void)
1972 {
1973         static initializer_t empty_initializer
1974                 = { .list = { { INITIALIZER_LIST }, 0 } };
1975         return &empty_initializer;
1976 }
1977
1978 /**
1979  * Parse a part of an initialiser for a struct or union,
1980  */
1981 static initializer_t *parse_sub_initializer(type_path_t *path,
1982                 type_t *outer_type, size_t top_path_level,
1983                 parse_initializer_env_t *env)
1984 {
1985         if (token.kind == '}') {
1986                 /* empty initializer */
1987                 return create_empty_initializer();
1988         }
1989
1990         type_t *orig_type = path->top_type;
1991         type_t *type      = NULL;
1992
1993         if (orig_type == NULL) {
1994                 /* We are initializing an empty compound. */
1995         } else {
1996                 type = skip_typeref(orig_type);
1997         }
1998
1999         initializer_t **initializers = NEW_ARR_F(initializer_t*, 0);
2000
2001         while (true) {
2002                 designator_t *designator = NULL;
2003                 if (token.kind == '.' || token.kind == '[') {
2004                         designator = parse_designation();
2005                         goto finish_designator;
2006                 } else if (token.kind == T_IDENTIFIER && look_ahead(1)->kind == ':') {
2007                         /* GNU-style designator ("identifier: value") */
2008                         designator = allocate_ast_zero(sizeof(designator[0]));
2009                         designator->source_position = *HERE;
2010                         designator->symbol          = token.base.symbol;
2011                         eat(T_IDENTIFIER);
2012                         eat(':');
2013
2014 finish_designator:
2015                         /* reset path to toplevel, evaluate designator from there */
2016                         ascend_to(path, top_path_level);
2017                         if (!walk_designator(path, designator, false)) {
2018                                 /* can't continue after designation error */
2019                                 goto end_error;
2020                         }
2021
2022                         initializer_t *designator_initializer
2023                                 = allocate_initializer_zero(INITIALIZER_DESIGNATOR);
2024                         designator_initializer->designator.designator = designator;
2025                         ARR_APP1(initializer_t*, initializers, designator_initializer);
2026
2027                         orig_type = path->top_type;
2028                         type      = orig_type != NULL ? skip_typeref(orig_type) : NULL;
2029                 }
2030
2031                 initializer_t *sub;
2032
2033                 if (token.kind == '{') {
2034                         if (type != NULL && is_type_scalar(type)) {
2035                                 sub = parse_scalar_initializer(type, env->must_be_constant);
2036                         } else {
2037                                 if (type == NULL) {
2038                                         if (env->entity != NULL) {
2039                                                 errorf(HERE, "extra brace group at end of initializer for '%N'", env->entity);
2040                                         } else {
2041                                                 errorf(HERE, "extra brace group at end of initializer");
2042                                         }
2043                                         eat('{');
2044                                 } else {
2045                                         eat('{');
2046                                         descend_into_subtype(path);
2047                                 }
2048
2049                                 add_anchor_token('}');
2050                                 sub = parse_sub_initializer(path, orig_type, top_path_level+1,
2051                                                             env);
2052                                 rem_anchor_token('}');
2053
2054                                 expect('}');
2055
2056                                 if (!type)
2057                                         goto error_parse_next;
2058
2059                                 ascend_from_subtype(path);
2060                         }
2061                 } else {
2062                         /* must be an expression */
2063                         expression_t *expression = parse_assignment_expression();
2064                         mark_vars_read(expression, NULL);
2065
2066                         if (env->must_be_constant && !is_linker_constant(expression)) {
2067                                 errorf(&expression->base.source_position,
2068                                        "Initialisation expression '%E' is not constant",
2069                                        expression);
2070                         }
2071
2072                         if (type == NULL) {
2073                                 /* we are already outside, ... */
2074                                 if (outer_type == NULL)
2075                                         goto error_parse_next;
2076                                 type_t *const outer_type_skip = skip_typeref(outer_type);
2077                                 if (is_type_compound(outer_type_skip) &&
2078                                                 !outer_type_skip->compound.compound->complete) {
2079                                         goto error_parse_next;
2080                                 }
2081
2082                                 source_position_t const* const pos = &expression->base.source_position;
2083                                 if (env->entity != NULL) {
2084                                         warningf(WARN_OTHER, pos, "excess elements in initializer for '%N'", env->entity);
2085                                 } else {
2086                                         warningf(WARN_OTHER, pos, "excess elements in initializer");
2087                                 }
2088                                 goto error_parse_next;
2089                         }
2090
2091                         /* handle { "string" } special case */
2092                         if (expression->kind == EXPR_STRING_LITERAL && outer_type != NULL) {
2093                                 sub = initializer_from_expression(outer_type, expression);
2094                                 if (sub != NULL) {
2095                                         next_if(',');
2096                                         if (token.kind != '}') {
2097                                                 warningf(WARN_OTHER, HERE, "excessive elements in initializer for type '%T'", orig_type);
2098                                         }
2099                                         /* TODO: eat , ... */
2100                                         return sub;
2101                                 }
2102                         }
2103
2104                         /* descend into subtypes until expression matches type */
2105                         while (true) {
2106                                 orig_type = path->top_type;
2107                                 type      = skip_typeref(orig_type);
2108
2109                                 sub = initializer_from_expression(orig_type, expression);
2110                                 if (sub != NULL) {
2111                                         break;
2112                                 }
2113                                 if (!is_type_valid(type)) {
2114                                         goto end_error;
2115                                 }
2116                                 if (is_type_scalar(type)) {
2117                                         errorf(&expression->base.source_position,
2118                                                         "expression '%E' doesn't match expected type '%T'",
2119                                                         expression, orig_type);
2120                                         goto end_error;
2121                                 }
2122
2123                                 descend_into_subtype(path);
2124                         }
2125                 }
2126
2127                 /* update largest index of top array */
2128                 const type_path_entry_t *first      = &path->path[0];
2129                 type_t                  *first_type = first->type;
2130                 first_type                          = skip_typeref(first_type);
2131                 if (is_type_array(first_type)) {
2132                         size_t index = first->v.index;
2133                         if (index > path->max_index)
2134                                 path->max_index = index;
2135                 }
2136
2137                 /* append to initializers list */
2138                 ARR_APP1(initializer_t*, initializers, sub);
2139
2140 error_parse_next:
2141                 if (token.kind == '}') {
2142                         break;
2143                 }
2144                 add_anchor_token('}');
2145                 expect(',');
2146                 rem_anchor_token('}');
2147                 if (token.kind == '}') {
2148                         break;
2149                 }
2150
2151                 if (type != NULL) {
2152                         /* advance to the next declaration if we are not at the end */
2153                         advance_current_object(path, top_path_level);
2154                         orig_type = path->top_type;
2155                         if (orig_type != NULL)
2156                                 type = skip_typeref(orig_type);
2157                         else
2158                                 type = NULL;
2159                 }
2160         }
2161
2162         size_t len  = ARR_LEN(initializers);
2163         size_t size = sizeof(initializer_list_t) + len * sizeof(initializers[0]);
2164         initializer_t *result = allocate_ast_zero(size);
2165         result->kind          = INITIALIZER_LIST;
2166         result->list.len      = len;
2167         memcpy(&result->list.initializers, initializers,
2168                len * sizeof(initializers[0]));
2169
2170         DEL_ARR_F(initializers);
2171         ascend_to(path, top_path_level+1);
2172
2173         return result;
2174
2175 end_error:
2176         skip_initializers();
2177         DEL_ARR_F(initializers);
2178         ascend_to(path, top_path_level+1);
2179         return NULL;
2180 }
2181
2182 static expression_t *make_size_literal(size_t value)
2183 {
2184         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_INTEGER);
2185         literal->base.type    = type_size_t;
2186
2187         char buf[128];
2188         snprintf(buf, sizeof(buf), "%u", (unsigned) value);
2189         literal->literal.value = make_string(buf);
2190
2191         return literal;
2192 }
2193
2194 /**
2195  * Parses an initializer. Parsers either a compound literal
2196  * (env->declaration == NULL) or an initializer of a declaration.
2197  */
2198 static initializer_t *parse_initializer(parse_initializer_env_t *env)
2199 {
2200         type_t        *type      = skip_typeref(env->type);
2201         size_t         max_index = 0;
2202         initializer_t *result;
2203
2204         if (is_type_scalar(type)) {
2205                 result = parse_scalar_initializer(type, env->must_be_constant);
2206         } else if (token.kind == '{') {
2207                 eat('{');
2208
2209                 type_path_t path;
2210                 memset(&path, 0, sizeof(path));
2211                 path.top_type = env->type;
2212                 path.path     = NEW_ARR_F(type_path_entry_t, 0);
2213
2214                 descend_into_subtype(&path);
2215
2216                 add_anchor_token('}');
2217                 result = parse_sub_initializer(&path, env->type, 1, env);
2218                 rem_anchor_token('}');
2219
2220                 max_index = path.max_index;
2221                 DEL_ARR_F(path.path);
2222
2223                 expect('}');
2224         } else {
2225                 /* parse_scalar_initializer() also works in this case: we simply
2226                  * have an expression without {} around it */
2227                 result = parse_scalar_initializer(type, env->must_be_constant);
2228         }
2229
2230         /* §6.7.8:22 array initializers for arrays with unknown size determine
2231          * the array type size */
2232         if (is_type_array(type) && type->array.size_expression == NULL
2233                         && result != NULL) {
2234                 size_t size;
2235                 switch (result->kind) {
2236                 case INITIALIZER_LIST:
2237                         assert(max_index != 0xdeadbeaf);
2238                         size = max_index + 1;
2239                         break;
2240
2241                 case INITIALIZER_STRING:
2242                         size = result->string.string.size + 1;
2243                         break;
2244
2245                 case INITIALIZER_WIDE_STRING:
2246                         size = result->wide_string.string.size;
2247                         break;
2248
2249                 case INITIALIZER_DESIGNATOR:
2250                 case INITIALIZER_VALUE:
2251                         /* can happen for parse errors */
2252                         size = 0;
2253                         break;
2254
2255                 default:
2256                         internal_errorf(HERE, "invalid initializer type");
2257                 }
2258
2259                 type_t *new_type = duplicate_type(type);
2260
2261                 new_type->array.size_expression   = make_size_literal(size);
2262                 new_type->array.size_constant     = true;
2263                 new_type->array.has_implicit_size = true;
2264                 new_type->array.size              = size;
2265                 env->type = new_type;
2266         }
2267
2268         return result;
2269 }
2270
2271 static void append_entity(scope_t *scope, entity_t *entity)
2272 {
2273         if (scope->last_entity != NULL) {
2274                 scope->last_entity->base.next = entity;
2275         } else {
2276                 scope->entities = entity;
2277         }
2278         entity->base.parent_entity = current_entity;
2279         scope->last_entity         = entity;
2280 }
2281
2282
2283 static compound_t *parse_compound_type_specifier(bool is_struct)
2284 {
2285         source_position_t const pos = *HERE;
2286         eat(is_struct ? T_struct : T_union);
2287
2288         symbol_t    *symbol     = NULL;
2289         entity_t    *entity     = NULL;
2290         attribute_t *attributes = NULL;
2291
2292         if (token.kind == T___attribute__) {
2293                 attributes = parse_attributes(NULL);
2294         }
2295
2296         entity_kind_tag_t const kind = is_struct ? ENTITY_STRUCT : ENTITY_UNION;
2297         if (token.kind == T_IDENTIFIER) {
2298                 /* the compound has a name, check if we have seen it already */
2299                 symbol = token.base.symbol;
2300                 entity = get_tag(symbol, kind);
2301                 eat(T_IDENTIFIER);
2302
2303                 if (entity != NULL) {
2304                         if (entity->base.parent_scope != current_scope &&
2305                             (token.kind == '{' || token.kind == ';')) {
2306                                 /* we're in an inner scope and have a definition. Shadow
2307                                  * existing definition in outer scope */
2308                                 entity = NULL;
2309                         } else if (entity->compound.complete && token.kind == '{') {
2310                                 source_position_t const *const ppos = &entity->base.source_position;
2311                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2312                                 /* clear members in the hope to avoid further errors */
2313                                 entity->compound.members.entities = NULL;
2314                         }
2315                 }
2316         } else if (token.kind != '{') {
2317                 char const *const msg =
2318                         is_struct ? "while parsing struct type specifier" :
2319                                     "while parsing union type specifier";
2320                 parse_error_expected(msg, T_IDENTIFIER, '{', NULL);
2321
2322                 return NULL;
2323         }
2324
2325         if (entity == NULL) {
2326                 entity = allocate_entity_zero(kind, NAMESPACE_TAG, symbol, &pos);
2327                 entity->compound.alignment = 1;
2328                 entity->base.parent_scope  = current_scope;
2329                 if (symbol != NULL) {
2330                         environment_push(entity);
2331                 }
2332                 append_entity(current_scope, entity);
2333         }
2334
2335         if (token.kind == '{') {
2336                 parse_compound_type_entries(&entity->compound);
2337
2338                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2339                 if (symbol == NULL) {
2340                         assert(anonymous_entity == NULL);
2341                         anonymous_entity = entity;
2342                 }
2343         }
2344
2345         if (attributes != NULL) {
2346                 handle_entity_attributes(attributes, entity);
2347         }
2348
2349         return &entity->compound;
2350 }
2351
2352 static void parse_enum_entries(type_t *const enum_type)
2353 {
2354         eat('{');
2355
2356         if (token.kind == '}') {
2357                 errorf(HERE, "empty enum not allowed");
2358                 eat('}');
2359                 return;
2360         }
2361
2362         add_anchor_token('}');
2363         add_anchor_token(',');
2364         do {
2365                 add_anchor_token('=');
2366                 source_position_t pos;
2367                 symbol_t *const symbol = expect_identifier("while parsing enum entry", &pos);
2368                 entity_t *const entity = allocate_entity_zero(ENTITY_ENUM_VALUE, NAMESPACE_NORMAL, symbol, &pos);
2369                 entity->enum_value.enum_type = enum_type;
2370                 rem_anchor_token('=');
2371
2372                 if (next_if('=')) {
2373                         expression_t *value = parse_constant_expression();
2374
2375                         value = create_implicit_cast(value, enum_type);
2376                         entity->enum_value.value = value;
2377
2378                         /* TODO semantic */
2379                 }
2380
2381                 record_entity(entity, false);
2382         } while (next_if(',') && token.kind != '}');
2383         rem_anchor_token(',');
2384         rem_anchor_token('}');
2385
2386         expect('}');
2387 }
2388
2389 static type_t *parse_enum_specifier(void)
2390 {
2391         source_position_t const pos = *HERE;
2392         entity_t               *entity;
2393         symbol_t               *symbol;
2394
2395         eat(T_enum);
2396         switch (token.kind) {
2397                 case T_IDENTIFIER:
2398                         symbol = token.base.symbol;
2399                         entity = get_tag(symbol, ENTITY_ENUM);
2400                         eat(T_IDENTIFIER);
2401
2402                         if (entity != NULL) {
2403                                 if (entity->base.parent_scope != current_scope &&
2404                                                 (token.kind == '{' || token.kind == ';')) {
2405                                         /* we're in an inner scope and have a definition. Shadow
2406                                          * existing definition in outer scope */
2407                                         entity = NULL;
2408                                 } else if (entity->enume.complete && token.kind == '{') {
2409                                         source_position_t const *const ppos = &entity->base.source_position;
2410                                         errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
2411                                 }
2412                         }
2413                         break;
2414
2415                 case '{':
2416                         entity = NULL;
2417                         symbol = NULL;
2418                         break;
2419
2420                 default:
2421                         parse_error_expected("while parsing enum type specifier",
2422                                         T_IDENTIFIER, '{', NULL);
2423                         return NULL;
2424         }
2425
2426         if (entity == NULL) {
2427                 entity = allocate_entity_zero(ENTITY_ENUM, NAMESPACE_TAG, symbol, &pos);
2428                 entity->base.parent_scope = current_scope;
2429         }
2430
2431         type_t *const type     = allocate_type_zero(TYPE_ENUM);
2432         type->enumt.enume      = &entity->enume;
2433         type->enumt.base.akind = ATOMIC_TYPE_INT;
2434
2435         if (token.kind == '{') {
2436                 if (symbol != NULL) {
2437                         environment_push(entity);
2438                 }
2439                 append_entity(current_scope, entity);
2440                 entity->enume.complete = true;
2441
2442                 parse_enum_entries(type);
2443                 parse_attributes(NULL);
2444
2445                 /* ISO/IEC 14882:1998(E) §7.1.3:5 */
2446                 if (symbol == NULL) {
2447                         assert(anonymous_entity == NULL);
2448                         anonymous_entity = entity;
2449                 }
2450         } else if (!entity->enume.complete && !(c_mode & _GNUC)) {
2451                 errorf(HERE, "'%T' used before definition (incomplete enums are a GNU extension)", type);
2452         }
2453
2454         return type;
2455 }
2456
2457 /**
2458  * if a symbol is a typedef to another type, return true
2459  */
2460 static bool is_typedef_symbol(symbol_t *symbol)
2461 {
2462         const entity_t *const entity = get_entity(symbol, NAMESPACE_NORMAL);
2463         return entity != NULL && entity->kind == ENTITY_TYPEDEF;
2464 }
2465
2466 static type_t *parse_typeof(void)
2467 {
2468         eat(T___typeof__);
2469
2470         type_t *type;
2471
2472         add_anchor_token(')');
2473         expect('(');
2474
2475         expression_t *expression  = NULL;
2476
2477         switch (token.kind) {
2478         case T_IDENTIFIER:
2479                 if (is_typedef_symbol(token.base.symbol)) {
2480         DECLARATION_START
2481                         type = parse_typename();
2482                 } else {
2483         default:
2484                         expression = parse_expression();
2485                         type       = revert_automatic_type_conversion(expression);
2486                 }
2487                 break;
2488         }
2489
2490         rem_anchor_token(')');
2491         expect(')');
2492
2493         type_t *typeof_type              = allocate_type_zero(TYPE_TYPEOF);
2494         typeof_type->typeoft.expression  = expression;
2495         typeof_type->typeoft.typeof_type = type;
2496
2497         return typeof_type;
2498 }
2499
2500 typedef enum specifiers_t {
2501         SPECIFIER_SIGNED    = 1 << 0,
2502         SPECIFIER_UNSIGNED  = 1 << 1,
2503         SPECIFIER_LONG      = 1 << 2,
2504         SPECIFIER_INT       = 1 << 3,
2505         SPECIFIER_DOUBLE    = 1 << 4,
2506         SPECIFIER_CHAR      = 1 << 5,
2507         SPECIFIER_WCHAR_T   = 1 << 6,
2508         SPECIFIER_SHORT     = 1 << 7,
2509         SPECIFIER_LONG_LONG = 1 << 8,
2510         SPECIFIER_FLOAT     = 1 << 9,
2511         SPECIFIER_BOOL      = 1 << 10,
2512         SPECIFIER_VOID      = 1 << 11,
2513         SPECIFIER_INT8      = 1 << 12,
2514         SPECIFIER_INT16     = 1 << 13,
2515         SPECIFIER_INT32     = 1 << 14,
2516         SPECIFIER_INT64     = 1 << 15,
2517         SPECIFIER_INT128    = 1 << 16,
2518         SPECIFIER_COMPLEX   = 1 << 17,
2519         SPECIFIER_IMAGINARY = 1 << 18,
2520 } specifiers_t;
2521
2522 static type_t *get_typedef_type(symbol_t *symbol)
2523 {
2524         entity_t *entity = get_entity(symbol, NAMESPACE_NORMAL);
2525         if (entity == NULL || entity->kind != ENTITY_TYPEDEF)
2526                 return NULL;
2527
2528         type_t *type            = allocate_type_zero(TYPE_TYPEDEF);
2529         type->typedeft.typedefe = &entity->typedefe;
2530
2531         return type;
2532 }
2533
2534 static attribute_t *parse_attribute_ms_property(attribute_t *attribute)
2535 {
2536         attribute_property_argument_t *const property = allocate_ast_zero(sizeof(*property));
2537
2538         add_anchor_token(')');
2539         add_anchor_token(',');
2540         expect('(');
2541
2542         do {
2543                 add_anchor_token('=');
2544                 source_position_t pos;
2545                 symbol_t *const prop_sym = expect_identifier("while parsing property declspec", &pos);
2546                 rem_anchor_token('=');
2547
2548                 symbol_t **prop = NULL;
2549                 if (prop_sym) {
2550                         if (streq(prop_sym->string, "put")) {
2551                                 prop = &property->put_symbol;
2552                         } else if (streq(prop_sym->string, "get")) {
2553                                 prop = &property->get_symbol;
2554                         } else {
2555                                 errorf(&pos, "expected put or get in property declspec, but got '%Y'", prop_sym);
2556                         }
2557                 }
2558
2559                 add_anchor_token(T_IDENTIFIER);
2560                 expect('=');
2561                 rem_anchor_token(T_IDENTIFIER);
2562
2563                 symbol_t *const sym = expect_identifier("while parsing property declspec", NULL);
2564                 if (prop != NULL)
2565                         *prop = sym ? sym : sym_anonymous;
2566         } while (next_if(','));
2567         rem_anchor_token(',');
2568         rem_anchor_token(')');
2569
2570         attribute->a.property = property;
2571
2572         expect(')');
2573         return attribute;
2574 }
2575
2576 static attribute_t *parse_microsoft_extended_decl_modifier_single(void)
2577 {
2578         attribute_kind_t kind = ATTRIBUTE_UNKNOWN;
2579         if (next_if(T_restrict)) {
2580                 kind = ATTRIBUTE_MS_RESTRICT;
2581         } else if (token.kind == T_IDENTIFIER) {
2582                 char const *const name = token.base.symbol->string;
2583                 for (attribute_kind_t k = ATTRIBUTE_MS_FIRST; k <= ATTRIBUTE_MS_LAST;
2584                      ++k) {
2585                         const char *attribute_name = get_attribute_name(k);
2586                         if (attribute_name != NULL && streq(attribute_name, name)) {
2587                                 kind = k;
2588                                 break;
2589                         }
2590                 }
2591
2592                 if (kind == ATTRIBUTE_UNKNOWN) {
2593                         warningf(WARN_ATTRIBUTE, HERE, "unknown __declspec '%s' ignored", name);
2594                 }
2595         } else {
2596                 parse_error_expected("while parsing __declspec", T_IDENTIFIER, NULL);
2597                 return NULL;
2598         }
2599
2600         attribute_t *attribute = allocate_attribute_zero(kind);
2601         eat(T_IDENTIFIER);
2602
2603         if (kind == ATTRIBUTE_MS_PROPERTY) {
2604                 return parse_attribute_ms_property(attribute);
2605         }
2606
2607         /* parse arguments */
2608         if (next_if('('))
2609                 attribute->a.arguments = parse_attribute_arguments();
2610
2611         return attribute;
2612 }
2613
2614 static attribute_t *parse_microsoft_extended_decl_modifier(attribute_t *first)
2615 {
2616         eat(T__declspec);
2617
2618         add_anchor_token(')');
2619         expect('(');
2620         if (token.kind != ')') {
2621                 attribute_t **anchor = &first;
2622                 do {
2623                         while (*anchor != NULL)
2624                                 anchor = &(*anchor)->next;
2625
2626                         attribute_t *attribute
2627                                 = parse_microsoft_extended_decl_modifier_single();
2628                         if (attribute == NULL)
2629                                 break;
2630
2631                         *anchor = attribute;
2632                         anchor  = &attribute->next;
2633                 } while (next_if(','));
2634         }
2635         rem_anchor_token(')');
2636         expect(')');
2637         return first;
2638 }
2639
2640 static entity_t *create_error_entity(symbol_t *symbol, entity_kind_tag_t kind)
2641 {
2642         entity_t *const entity = allocate_entity_zero(kind, NAMESPACE_NORMAL, symbol, HERE);
2643         if (is_declaration(entity)) {
2644                 entity->declaration.type     = type_error_type;
2645                 entity->declaration.implicit = true;
2646         } else if (kind == ENTITY_TYPEDEF) {
2647                 entity->typedefe.type    = type_error_type;
2648                 entity->typedefe.builtin = true;
2649         }
2650         if (kind != ENTITY_COMPOUND_MEMBER)
2651                 record_entity(entity, false);
2652         return entity;
2653 }
2654
2655 static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
2656 {
2657         type_t            *type            = NULL;
2658         type_qualifiers_t  qualifiers      = TYPE_QUALIFIER_NONE;
2659         unsigned           type_specifiers = 0;
2660         bool               newtype         = false;
2661         bool               saw_error       = false;
2662
2663         memset(specifiers, 0, sizeof(*specifiers));
2664         specifiers->source_position = *HERE;
2665
2666         while (true) {
2667                 specifiers->attributes = parse_attributes(specifiers->attributes);
2668
2669                 switch (token.kind) {
2670                 /* storage class */
2671 #define MATCH_STORAGE_CLASS(token, class)                                  \
2672                 case token:                                                        \
2673                         if (specifiers->storage_class != STORAGE_CLASS_NONE) {         \
2674                                 errorf(HERE, "multiple storage classes in declaration specifiers"); \
2675                         }                                                              \
2676                         specifiers->storage_class = class;                             \
2677                         if (specifiers->thread_local)                                  \
2678                                 goto check_thread_storage_class;                           \
2679                         eat(token); \
2680                         break;
2681
2682                 MATCH_STORAGE_CLASS(T_typedef,  STORAGE_CLASS_TYPEDEF)
2683                 MATCH_STORAGE_CLASS(T_extern,   STORAGE_CLASS_EXTERN)
2684                 MATCH_STORAGE_CLASS(T_static,   STORAGE_CLASS_STATIC)
2685                 MATCH_STORAGE_CLASS(T_auto,     STORAGE_CLASS_AUTO)
2686                 MATCH_STORAGE_CLASS(T_register, STORAGE_CLASS_REGISTER)
2687
2688                 case T__declspec:
2689                         specifiers->attributes
2690                                 = parse_microsoft_extended_decl_modifier(specifiers->attributes);
2691                         break;
2692
2693                 case T___thread:
2694                         if (specifiers->thread_local) {
2695                                 errorf(HERE, "duplicate '__thread'");
2696                         } else {
2697                                 specifiers->thread_local = true;
2698 check_thread_storage_class:
2699                                 switch (specifiers->storage_class) {
2700                                         case STORAGE_CLASS_EXTERN:
2701                                         case STORAGE_CLASS_NONE:
2702                                         case STORAGE_CLASS_STATIC:
2703                                                 break;
2704
2705                                                 char const* wrong;
2706                                         case STORAGE_CLASS_AUTO:     wrong = "auto";     goto wrong_thread_storage_class;
2707                                         case STORAGE_CLASS_REGISTER: wrong = "register"; goto wrong_thread_storage_class;
2708                                         case STORAGE_CLASS_TYPEDEF:  wrong = "typedef";  goto wrong_thread_storage_class;
2709 wrong_thread_storage_class:
2710                                                 errorf(HERE, "'__thread' used with '%s'", wrong);
2711                                                 break;
2712                                 }
2713                         }
2714                         next_token();
2715                         break;
2716
2717                 /* type qualifiers */
2718 #define MATCH_TYPE_QUALIFIER(token, qualifier)                          \
2719                 case token:                                                     \
2720                         qualifiers |= qualifier;                                    \
2721                         eat(token); \
2722                         break
2723
2724                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
2725                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
2726                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
2727                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
2728                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
2729                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
2730                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
2731                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
2732
2733                 /* type specifiers */
2734 #define MATCH_SPECIFIER(token, specifier, name)                         \
2735                 case token:                                                     \
2736                         if (type_specifiers & specifier) {                           \
2737                                 errorf(HERE, "multiple " name " type specifiers given"); \
2738                         } else {                                                    \
2739                                 type_specifiers |= specifier;                           \
2740                         }                                                           \
2741                         eat(token); \
2742                         break
2743
2744                 MATCH_SPECIFIER(T__Bool,      SPECIFIER_BOOL,      "_Bool");
2745                 MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex");
2746                 MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary");
2747                 MATCH_SPECIFIER(T__int128,    SPECIFIER_INT128,    "_int128");
2748                 MATCH_SPECIFIER(T__int16,     SPECIFIER_INT16,     "_int16");
2749                 MATCH_SPECIFIER(T__int32,     SPECIFIER_INT32,     "_int32");
2750                 MATCH_SPECIFIER(T__int64,     SPECIFIER_INT64,     "_int64");
2751                 MATCH_SPECIFIER(T__int8,      SPECIFIER_INT8,      "_int8");
2752                 MATCH_SPECIFIER(T_bool,       SPECIFIER_BOOL,      "bool");
2753                 MATCH_SPECIFIER(T_char,       SPECIFIER_CHAR,      "char");
2754                 MATCH_SPECIFIER(T_double,     SPECIFIER_DOUBLE,    "double");
2755                 MATCH_SPECIFIER(T_float,      SPECIFIER_FLOAT,     "float");
2756                 MATCH_SPECIFIER(T_int,        SPECIFIER_INT,       "int");
2757                 MATCH_SPECIFIER(T_short,      SPECIFIER_SHORT,     "short");
2758                 MATCH_SPECIFIER(T_signed,     SPECIFIER_SIGNED,    "signed");
2759                 MATCH_SPECIFIER(T_unsigned,   SPECIFIER_UNSIGNED,  "unsigned");
2760                 MATCH_SPECIFIER(T_void,       SPECIFIER_VOID,      "void");
2761                 MATCH_SPECIFIER(T_wchar_t,    SPECIFIER_WCHAR_T,   "wchar_t");
2762
2763                 case T_inline:
2764                         eat(T_inline);
2765                         specifiers->is_inline = true;
2766                         break;
2767
2768 #if 0
2769                 case T__forceinline:
2770                         eat(T__forceinline);
2771                         specifiers->modifiers |= DM_FORCEINLINE;
2772                         break;
2773 #endif
2774
2775                 case T_long:
2776                         if (type_specifiers & SPECIFIER_LONG_LONG) {
2777                                 errorf(HERE, "too many long type specifiers given");
2778                         } else if (type_specifiers & SPECIFIER_LONG) {
2779                                 type_specifiers |= SPECIFIER_LONG_LONG;
2780                         } else {
2781                                 type_specifiers |= SPECIFIER_LONG;
2782                         }
2783                         eat(T_long);
2784                         break;
2785
2786 #define CHECK_DOUBLE_TYPE() \
2787         (type != NULL ? errorf(HERE, "multiple types in declaration specifiers") : (void)0)
2788
2789                 case T_struct:
2790                         CHECK_DOUBLE_TYPE();
2791                         type = allocate_type_zero(TYPE_COMPOUND_STRUCT);
2792
2793                         type->compound.compound = parse_compound_type_specifier(true);
2794                         break;
2795                 case T_union:
2796                         CHECK_DOUBLE_TYPE();
2797                         type = allocate_type_zero(TYPE_COMPOUND_UNION);
2798                         type->compound.compound = parse_compound_type_specifier(false);
2799                         break;
2800                 case T_enum:
2801                         CHECK_DOUBLE_TYPE();
2802                         type = parse_enum_specifier();
2803                         break;
2804                 case T___typeof__:
2805                         CHECK_DOUBLE_TYPE();
2806                         type = parse_typeof();
2807                         break;
2808                 case T___builtin_va_list:
2809                         CHECK_DOUBLE_TYPE();
2810                         type = duplicate_type(type_valist);
2811                         eat(T___builtin_va_list);
2812                         break;
2813
2814                 case T_IDENTIFIER: {
2815                         /* only parse identifier if we haven't found a type yet */
2816                         if (type != NULL || type_specifiers != 0) {
2817                                 /* Be somewhat resilient to typos like 'unsigned lng* f()' in a
2818                                  * declaration, so it doesn't generate errors about expecting '(' or
2819                                  * '{' later on. */
2820                                 switch (look_ahead(1)->kind) {
2821                                         STORAGE_CLASSES
2822                                         TYPE_SPECIFIERS
2823                                         case T_const:
2824                                         case T_restrict:
2825                                         case T_volatile:
2826                                         case T_inline:
2827                                         case T__forceinline: /* ^ DECLARATION_START except for __attribute__ */
2828                                         case T_IDENTIFIER:
2829                                         case '&':
2830                                         case '*':
2831                                                 errorf(HERE, "discarding stray %K in declaration specifier", &token);
2832                                                 eat(T_IDENTIFIER);
2833                                                 continue;
2834
2835                                         default:
2836                                                 goto finish_specifiers;
2837                                 }
2838                         }
2839
2840                         type_t *const typedef_type = get_typedef_type(token.base.symbol);
2841                         if (typedef_type == NULL) {
2842                                 /* Be somewhat resilient to typos like 'vodi f()' at the beginning of a
2843                                  * declaration, so it doesn't generate 'implicit int' followed by more
2844                                  * errors later on. */
2845                                 token_kind_t const la1_type = (token_kind_t)look_ahead(1)->kind;
2846                                 switch (la1_type) {
2847                                         DECLARATION_START
2848                                         case T_IDENTIFIER:
2849                                         case '&':
2850                                         case '*': {
2851                                                 errorf(HERE, "%K does not name a type", &token);
2852
2853                                                 entity_t *const entity = create_error_entity(token.base.symbol, ENTITY_TYPEDEF);
2854
2855                                                 type = allocate_type_zero(TYPE_TYPEDEF);
2856                                                 type->typedeft.typedefe = &entity->typedefe;
2857
2858                                                 eat(T_IDENTIFIER);
2859                                                 saw_error = true;
2860                                                 continue;
2861                                         }
2862
2863                                         default:
2864                                                 goto finish_specifiers;
2865                                 }
2866                         }
2867
2868                         eat(T_IDENTIFIER);
2869                         type = typedef_type;
2870                         break;
2871                 }
2872
2873                 /* function specifier */
2874                 default:
2875                         goto finish_specifiers;
2876                 }
2877         }
2878
2879 finish_specifiers:
2880         specifiers->attributes = parse_attributes(specifiers->attributes);
2881
2882         if (type == NULL || (saw_error && type_specifiers != 0)) {
2883                 atomic_type_kind_t atomic_type;
2884
2885                 /* match valid basic types */
2886                 switch (type_specifiers) {
2887                 case SPECIFIER_VOID:
2888                         atomic_type = ATOMIC_TYPE_VOID;
2889                         break;
2890                 case SPECIFIER_WCHAR_T:
2891                         atomic_type = ATOMIC_TYPE_WCHAR_T;
2892                         break;
2893                 case SPECIFIER_CHAR:
2894                         atomic_type = ATOMIC_TYPE_CHAR;
2895                         break;
2896                 case SPECIFIER_SIGNED | SPECIFIER_CHAR:
2897                         atomic_type = ATOMIC_TYPE_SCHAR;
2898                         break;
2899                 case SPECIFIER_UNSIGNED | SPECIFIER_CHAR:
2900                         atomic_type = ATOMIC_TYPE_UCHAR;
2901                         break;
2902                 case SPECIFIER_SHORT:
2903                 case SPECIFIER_SIGNED | SPECIFIER_SHORT:
2904                 case SPECIFIER_SHORT | SPECIFIER_INT:
2905                 case SPECIFIER_SIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2906                         atomic_type = ATOMIC_TYPE_SHORT;
2907                         break;
2908                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT:
2909                 case SPECIFIER_UNSIGNED | SPECIFIER_SHORT | SPECIFIER_INT:
2910                         atomic_type = ATOMIC_TYPE_USHORT;
2911                         break;
2912                 case SPECIFIER_INT:
2913                 case SPECIFIER_SIGNED:
2914                 case SPECIFIER_SIGNED | SPECIFIER_INT:
2915                         atomic_type = ATOMIC_TYPE_INT;
2916                         break;
2917                 case SPECIFIER_UNSIGNED:
2918                 case SPECIFIER_UNSIGNED | SPECIFIER_INT:
2919                         atomic_type = ATOMIC_TYPE_UINT;
2920                         break;
2921                 case SPECIFIER_LONG:
2922                 case SPECIFIER_SIGNED | SPECIFIER_LONG:
2923                 case SPECIFIER_LONG | SPECIFIER_INT:
2924                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2925                         atomic_type = ATOMIC_TYPE_LONG;
2926                         break;
2927                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG:
2928                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_INT:
2929                         atomic_type = ATOMIC_TYPE_ULONG;
2930                         break;
2931
2932                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2933                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2934                 case SPECIFIER_LONG | SPECIFIER_LONG_LONG | SPECIFIER_INT:
2935                 case SPECIFIER_SIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2936                         | SPECIFIER_INT:
2937                         atomic_type = ATOMIC_TYPE_LONGLONG;
2938                         goto warn_about_long_long;
2939
2940                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG:
2941                 case SPECIFIER_UNSIGNED | SPECIFIER_LONG | SPECIFIER_LONG_LONG
2942                         | SPECIFIER_INT:
2943                         atomic_type = ATOMIC_TYPE_ULONGLONG;
2944 warn_about_long_long:
2945                         warningf(WARN_LONG_LONG, &specifiers->source_position, "ISO C90 does not support 'long long'");
2946                         break;
2947
2948                 case SPECIFIER_UNSIGNED | SPECIFIER_INT8:
2949                         atomic_type = unsigned_int8_type_kind;
2950                         break;
2951
2952                 case SPECIFIER_UNSIGNED | SPECIFIER_INT16:
2953                         atomic_type = unsigned_int16_type_kind;
2954                         break;
2955
2956                 case SPECIFIER_UNSIGNED | SPECIFIER_INT32:
2957                         atomic_type = unsigned_int32_type_kind;
2958                         break;
2959
2960                 case SPECIFIER_UNSIGNED | SPECIFIER_INT64:
2961                         atomic_type = unsigned_int64_type_kind;
2962                         break;
2963
2964                 case SPECIFIER_UNSIGNED | SPECIFIER_INT128:
2965                         atomic_type = unsigned_int128_type_kind;
2966                         break;
2967
2968                 case SPECIFIER_INT8:
2969                 case SPECIFIER_SIGNED | SPECIFIER_INT8:
2970                         atomic_type = int8_type_kind;
2971                         break;
2972
2973                 case SPECIFIER_INT16:
2974                 case SPECIFIER_SIGNED | SPECIFIER_INT16:
2975                         atomic_type = int16_type_kind;
2976                         break;
2977
2978                 case SPECIFIER_INT32:
2979                 case SPECIFIER_SIGNED | SPECIFIER_INT32:
2980                         atomic_type = int32_type_kind;
2981                         break;
2982
2983                 case SPECIFIER_INT64:
2984                 case SPECIFIER_SIGNED | SPECIFIER_INT64:
2985                         atomic_type = int64_type_kind;
2986                         break;
2987
2988                 case SPECIFIER_INT128:
2989                 case SPECIFIER_SIGNED | SPECIFIER_INT128:
2990                         atomic_type = int128_type_kind;
2991                         break;
2992
2993                 case SPECIFIER_FLOAT:
2994                         atomic_type = ATOMIC_TYPE_FLOAT;
2995                         break;
2996                 case SPECIFIER_DOUBLE:
2997                         atomic_type = ATOMIC_TYPE_DOUBLE;
2998                         break;
2999                 case SPECIFIER_LONG | SPECIFIER_DOUBLE:
3000                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
3001                         break;
3002                 case SPECIFIER_BOOL:
3003                         atomic_type = ATOMIC_TYPE_BOOL;
3004                         break;
3005                 case SPECIFIER_FLOAT | SPECIFIER_COMPLEX:
3006                 case SPECIFIER_FLOAT | SPECIFIER_IMAGINARY:
3007                         atomic_type = ATOMIC_TYPE_FLOAT;
3008                         break;
3009                 case SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
3010                 case SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
3011                         atomic_type = ATOMIC_TYPE_DOUBLE;
3012                         break;
3013                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_COMPLEX:
3014                 case SPECIFIER_LONG | SPECIFIER_DOUBLE | SPECIFIER_IMAGINARY:
3015                         atomic_type = ATOMIC_TYPE_LONG_DOUBLE;
3016                         break;
3017                 default: {
3018                         /* invalid specifier combination, give an error message */
3019                         source_position_t const* const pos = &specifiers->source_position;
3020                         if (type_specifiers == 0) {
3021                                 if (!saw_error) {
3022                                         /* ISO/IEC 14882:1998(E) §C.1.5:4 */
3023                                         if (!(c_mode & _CXX) && !strict_mode) {
3024                                                 warningf(WARN_IMPLICIT_INT, pos, "no type specifiers in declaration, using 'int'");
3025                                                 atomic_type = ATOMIC_TYPE_INT;
3026                                                 break;
3027                                         } else {
3028                                                 errorf(pos, "no type specifiers given in declaration");
3029                                         }
3030                                 }
3031                         } else if ((type_specifiers & SPECIFIER_SIGNED) &&
3032                                   (type_specifiers & SPECIFIER_UNSIGNED)) {
3033                                 errorf(pos, "signed and unsigned specifiers given");
3034                         } else if (type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
3035                                 errorf(pos, "only integer types can be signed or unsigned");
3036                         } else {
3037                                 errorf(pos, "multiple datatypes in declaration");
3038                         }
3039                         goto end_error;
3040                 }
3041                 }
3042
3043                 if (type_specifiers & SPECIFIER_COMPLEX) {
3044                         type = allocate_type_zero(TYPE_COMPLEX);
3045                 } else if (type_specifiers & SPECIFIER_IMAGINARY) {
3046                         type = allocate_type_zero(TYPE_IMAGINARY);
3047                 } else {
3048                         type = allocate_type_zero(TYPE_ATOMIC);
3049                 }
3050                 type->atomic.akind = atomic_type;
3051                 newtype = true;
3052         } else if (type_specifiers != 0) {
3053                 errorf(&specifiers->source_position, "multiple datatypes in declaration");
3054         }
3055
3056         /* FIXME: check type qualifiers here */
3057         type->base.qualifiers = qualifiers;
3058
3059         if (newtype) {
3060                 type = identify_new_type(type);
3061         } else {
3062                 type = typehash_insert(type);
3063         }
3064
3065         if (specifiers->attributes != NULL)
3066                 type = handle_type_attributes(specifiers->attributes, type);
3067         specifiers->type = type;
3068         return;
3069
3070 end_error:
3071         specifiers->type = type_error_type;
3072 }
3073
3074 static type_qualifiers_t parse_type_qualifiers(void)
3075 {
3076         type_qualifiers_t qualifiers = TYPE_QUALIFIER_NONE;
3077
3078         while (true) {
3079                 switch (token.kind) {
3080                 /* type qualifiers */
3081                 MATCH_TYPE_QUALIFIER(T_const,    TYPE_QUALIFIER_CONST);
3082                 MATCH_TYPE_QUALIFIER(T_restrict, TYPE_QUALIFIER_RESTRICT);
3083                 MATCH_TYPE_QUALIFIER(T_volatile, TYPE_QUALIFIER_VOLATILE);
3084                 /* microsoft extended type modifiers */
3085                 MATCH_TYPE_QUALIFIER(T__w64,     TYPE_QUALIFIER_W64);
3086                 MATCH_TYPE_QUALIFIER(T___ptr32,  TYPE_QUALIFIER_PTR32);
3087                 MATCH_TYPE_QUALIFIER(T___ptr64,  TYPE_QUALIFIER_PTR64);
3088                 MATCH_TYPE_QUALIFIER(T___uptr,   TYPE_QUALIFIER_UPTR);
3089                 MATCH_TYPE_QUALIFIER(T___sptr,   TYPE_QUALIFIER_SPTR);
3090
3091                 default:
3092                         return qualifiers;
3093                 }
3094         }
3095 }
3096
3097 /**
3098  * Parses an K&R identifier list
3099  */
3100 static void parse_identifier_list(scope_t *scope)
3101 {
3102         assert(token.kind == T_IDENTIFIER);
3103         do {
3104                 entity_t *const entity = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, token.base.symbol, HERE);
3105                 /* a K&R parameter has no type, yet */
3106                 eat(T_IDENTIFIER);
3107
3108                 if (scope != NULL)
3109                         append_entity(scope, entity);
3110         } while (next_if(',') && token.kind == T_IDENTIFIER);
3111 }
3112
3113 static entity_t *parse_parameter(void)
3114 {
3115         declaration_specifiers_t specifiers;
3116         parse_declaration_specifiers(&specifiers);
3117
3118         entity_t *entity = parse_declarator(&specifiers,
3119                         DECL_MAY_BE_ABSTRACT | DECL_IS_PARAMETER);
3120         anonymous_entity = NULL;
3121         return entity;
3122 }
3123
3124 static void semantic_parameter_incomplete(const entity_t *entity)
3125 {
3126         assert(entity->kind == ENTITY_PARAMETER);
3127
3128         /* §6.7.5.3:4  After adjustment, the parameters in a parameter type
3129          *             list in a function declarator that is part of a
3130          *             definition of that function shall not have
3131          *             incomplete type. */
3132         type_t *type = skip_typeref(entity->declaration.type);
3133         if (is_type_incomplete(type)) {
3134                 errorf(&entity->base.source_position, "'%N' has incomplete type", entity);
3135         }
3136 }
3137
3138 static bool has_parameters(void)
3139 {
3140         /* func(void) is not a parameter */
3141         if (look_ahead(1)->kind != ')')
3142                 return true;
3143         if (token.kind == T_IDENTIFIER) {
3144                 entity_t const *const entity = get_entity(token.base.symbol, NAMESPACE_NORMAL);
3145                 if (entity == NULL)
3146                         return true;
3147                 if (entity->kind != ENTITY_TYPEDEF)
3148                         return true;
3149                 type_t const *const type = skip_typeref(entity->typedefe.type);
3150                 if (!is_type_void(type))
3151                         return true;
3152                 if (c_mode & _CXX) {
3153                         /* ISO/IEC 14882:1998(E) §8.3.5:2  It must be literally (void).  A typedef
3154                          * is not allowed. */
3155                         errorf(HERE, "empty parameter list defined with a typedef of 'void' not allowed in C++");
3156                 } else if (type->base.qualifiers != TYPE_QUALIFIER_NONE) {
3157                         /* §6.7.5.3:10  Qualification is not allowed here. */
3158                         errorf(HERE, "'void' as parameter must not have type qualifiers");
3159                 }
3160         } else if (token.kind != T_void) {
3161                 return true;
3162         }
3163         next_token();
3164         return false;
3165 }
3166
3167 /**
3168  * Parses function type parameters (and optionally creates variable_t entities
3169  * for them in a scope)
3170  */
3171 static void parse_parameters(function_type_t *type, scope_t *scope)
3172 {
3173         add_anchor_token(')');
3174         eat('(');
3175
3176         if (token.kind == T_IDENTIFIER            &&
3177             !is_typedef_symbol(token.base.symbol) &&
3178             (look_ahead(1)->kind == ',' || look_ahead(1)->kind == ')')) {
3179                 type->kr_style_parameters = true;
3180                 parse_identifier_list(scope);
3181         } else if (token.kind == ')') {
3182                 /* ISO/IEC 14882:1998(E) §C.1.6:1 */
3183                 if (!(c_mode & _CXX))
3184                         type->unspecified_parameters = true;
3185         } else if (has_parameters()) {
3186                 function_parameter_t **anchor = &type->parameters;
3187                 add_anchor_token(',');
3188                 do {
3189                         switch (token.kind) {
3190                         case T_DOTDOTDOT:
3191                                 eat(T_DOTDOTDOT);
3192                                 type->variadic = true;
3193                                 goto parameters_finished;
3194
3195                         case T_IDENTIFIER:
3196                         DECLARATION_START
3197                         {
3198                                 entity_t *entity = parse_parameter();
3199                                 if (entity->kind == ENTITY_TYPEDEF) {
3200                                         errorf(&entity->base.source_position,
3201                                                         "typedef not allowed as function parameter");
3202                                         break;
3203                                 }
3204                                 assert(is_declaration(entity));
3205
3206                                 semantic_parameter_incomplete(entity);
3207
3208                                 function_parameter_t *const parameter =
3209                                         allocate_parameter(entity->declaration.type);
3210
3211                                 if (scope != NULL) {
3212                                         append_entity(scope, entity);
3213                                 }
3214
3215                                 *anchor = parameter;
3216                                 anchor  = &parameter->next;
3217                                 break;
3218                         }
3219
3220                         default:
3221                                 goto parameters_finished;
3222                         }
3223                 } while (next_if(','));
3224 parameters_finished:
3225                 rem_anchor_token(',');
3226         }
3227
3228         rem_anchor_token(')');
3229         expect(')');
3230 }
3231
3232 typedef enum construct_type_kind_t {
3233         CONSTRUCT_POINTER = 1,
3234         CONSTRUCT_REFERENCE,
3235         CONSTRUCT_FUNCTION,
3236         CONSTRUCT_ARRAY
3237 } construct_type_kind_t;
3238
3239 typedef union construct_type_t construct_type_t;
3240
3241 typedef struct construct_type_base_t {
3242         construct_type_kind_t  kind;
3243         source_position_t      pos;
3244         construct_type_t      *next;
3245 } construct_type_base_t;
3246
3247 typedef struct parsed_pointer_t {
3248         construct_type_base_t  base;
3249         type_qualifiers_t      type_qualifiers;
3250         variable_t            *base_variable;  /**< MS __based extension. */
3251 } parsed_pointer_t;
3252
3253 typedef struct parsed_reference_t {
3254         construct_type_base_t base;
3255 } parsed_reference_t;
3256
3257 typedef struct construct_function_type_t {
3258         construct_type_base_t  base;
3259         type_t                *function_type;
3260 } construct_function_type_t;
3261
3262 typedef struct parsed_array_t {
3263         construct_type_base_t  base;
3264         type_qualifiers_t      type_qualifiers;
3265         bool                   is_static;
3266         bool                   is_variable;
3267         expression_t          *size;
3268 } parsed_array_t;
3269
3270 union construct_type_t {
3271         construct_type_kind_t     kind;
3272         construct_type_base_t     base;
3273         parsed_pointer_t          pointer;
3274         parsed_reference_t        reference;
3275         construct_function_type_t function;
3276         parsed_array_t            array;
3277 };
3278
3279 static construct_type_t *allocate_declarator_zero(construct_type_kind_t const kind, size_t const size)
3280 {
3281         construct_type_t *const cons = obstack_alloc(&temp_obst, size);
3282         memset(cons, 0, size);
3283         cons->kind     = kind;
3284         cons->base.pos = *HERE;
3285         return cons;
3286 }
3287
3288 /* §6.7.5.1 */
3289 static construct_type_t *parse_pointer_declarator(void)
3290 {
3291         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_POINTER, sizeof(parsed_pointer_t));
3292         eat('*');
3293         cons->pointer.type_qualifiers = parse_type_qualifiers();
3294         //cons->pointer.base_variable   = base_variable;
3295
3296         return cons;
3297 }
3298
3299 /* ISO/IEC 14882:1998(E) §8.3.2 */
3300 static construct_type_t *parse_reference_declarator(void)
3301 {
3302         if (!(c_mode & _CXX))
3303                 errorf(HERE, "references are only available for C++");
3304
3305         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_REFERENCE, sizeof(parsed_reference_t));
3306         eat('&');
3307
3308         return cons;
3309 }
3310
3311 /* §6.7.5.2 */
3312 static construct_type_t *parse_array_declarator(void)
3313 {
3314         construct_type_t *const cons  = allocate_declarator_zero(CONSTRUCT_ARRAY, sizeof(parsed_array_t));
3315         parsed_array_t   *const array = &cons->array;
3316
3317         eat('[');
3318         add_anchor_token(']');
3319
3320         bool is_static = next_if(T_static);
3321
3322         type_qualifiers_t type_qualifiers = parse_type_qualifiers();
3323
3324         if (!is_static)
3325                 is_static = next_if(T_static);
3326
3327         array->type_qualifiers = type_qualifiers;
3328         array->is_static       = is_static;
3329
3330         expression_t *size = NULL;
3331         if (token.kind == '*' && look_ahead(1)->kind == ']') {
3332                 array->is_variable = true;
3333                 eat('*');
3334         } else if (token.kind != ']') {
3335                 size = parse_assignment_expression();
3336
3337                 /* §6.7.5.2:1  Array size must have integer type */
3338                 type_t *const orig_type = size->base.type;
3339                 type_t *const type      = skip_typeref(orig_type);
3340                 if (!is_type_integer(type) && is_type_valid(type)) {
3341                         errorf(&size->base.source_position,
3342                                "array size '%E' must have integer type but has type '%T'",
3343                                size, orig_type);
3344                 }
3345
3346                 array->size = size;
3347                 mark_vars_read(size, NULL);
3348         }
3349
3350         if (is_static && size == NULL)
3351                 errorf(&array->base.pos, "static array parameters require a size");
3352
3353         rem_anchor_token(']');
3354         expect(']');
3355         return cons;
3356 }
3357
3358 /* §6.7.5.3 */
3359 static construct_type_t *parse_function_declarator(scope_t *scope)
3360 {
3361         construct_type_t *const cons = allocate_declarator_zero(CONSTRUCT_FUNCTION, sizeof(construct_function_type_t));
3362
3363         type_t          *type  = allocate_type_zero(TYPE_FUNCTION);
3364         function_type_t *ftype = &type->function;
3365
3366         ftype->linkage            = current_linkage;
3367         ftype->calling_convention = CC_DEFAULT;
3368
3369         parse_parameters(ftype, scope);
3370
3371         cons->function.function_type = type;
3372
3373         return cons;
3374 }
3375
3376 typedef struct parse_declarator_env_t {
3377         bool               may_be_abstract : 1;
3378         bool               must_be_abstract : 1;
3379         decl_modifiers_t   modifiers;
3380         symbol_t          *symbol;
3381         source_position_t  source_position;
3382         scope_t            parameters;
3383         attribute_t       *attributes;
3384 } parse_declarator_env_t;
3385
3386 /* §6.7.5 */
3387 static construct_type_t *parse_inner_declarator(parse_declarator_env_t *env)
3388 {
3389         /* construct a single linked list of construct_type_t's which describe
3390          * how to construct the final declarator type */
3391         construct_type_t  *first      = NULL;
3392         construct_type_t **anchor     = &first;
3393
3394         env->attributes = parse_attributes(env->attributes);
3395
3396         for (;;) {
3397                 construct_type_t *type;
3398                 //variable_t       *based = NULL; /* MS __based extension */
3399                 switch (token.kind) {
3400                         case '&':
3401                                 type = parse_reference_declarator();
3402                                 break;
3403
3404                         case T__based: {
3405                                 panic("based not supported anymore");
3406                                 /* FALLTHROUGH */
3407                         }
3408
3409                         case '*':
3410                                 type = parse_pointer_declarator();
3411                                 break;
3412
3413                         default:
3414                                 goto ptr_operator_end;
3415                 }
3416
3417                 *anchor = type;
3418                 anchor  = &type->base.next;
3419
3420                 /* TODO: find out if this is correct */
3421                 env->attributes = parse_attributes(env->attributes);
3422         }
3423
3424 ptr_operator_end: ;
3425         construct_type_t *inner_types = NULL;
3426
3427         switch (token.kind) {
3428         case T_IDENTIFIER:
3429                 if (env->must_be_abstract) {
3430                         errorf(HERE, "no identifier expected in typename");
3431                 } else {
3432                         env->symbol          = token.base.symbol;
3433                         env->source_position = *HERE;
3434                 }
3435                 eat(T_IDENTIFIER);
3436                 break;
3437
3438         case '(': {
3439                 /* Parenthesized declarator or function declarator? */
3440                 token_t const *const la1 = look_ahead(1);
3441                 switch (la1->kind) {
3442                         case T_IDENTIFIER:
3443                                 if (is_typedef_symbol(la1->base.symbol)) {
3444                         case ')':
3445                                         /* §6.7.6:2 footnote 126:  Empty parentheses in a type name are
3446                                          * interpreted as ``function with no parameter specification'', rather
3447                                          * than redundant parentheses around the omitted identifier. */
3448                         default:
3449                                         /* Function declarator. */
3450                                         if (!env->may_be_abstract) {
3451                                                 errorf(HERE, "function declarator must have a name");
3452                                         }
3453                                 } else {
3454                         case '&':
3455                         case '(':
3456                         case '*':
3457                         case '[':
3458                         case T___attribute__: /* FIXME __attribute__ might also introduce a parameter of a function declarator. */
3459                                         /* Paranthesized declarator. */
3460                                         eat('(');
3461                                         add_anchor_token(')');
3462                                         inner_types = parse_inner_declarator(env);
3463                                         if (inner_types != NULL) {
3464                                                 /* All later declarators only modify the return type */
3465                                                 env->must_be_abstract = true;
3466                                         }
3467                                         rem_anchor_token(')');
3468                                         expect(')');
3469                                 }
3470                                 break;
3471                 }
3472                 break;
3473         }
3474
3475         default:
3476                 if (env->may_be_abstract)
3477                         break;
3478                 parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', NULL);
3479                 eat_until_anchor();
3480                 return NULL;
3481         }
3482
3483         construct_type_t **const p = anchor;
3484
3485         for (;;) {
3486                 construct_type_t *type;
3487                 switch (token.kind) {
3488                 case '(': {
3489                         scope_t *scope = NULL;
3490                         if (!env->must_be_abstract) {
3491                                 scope = &env->parameters;
3492                         }
3493
3494                         type = parse_function_declarator(scope);
3495                         break;
3496                 }
3497                 case '[':
3498                         type = parse_array_declarator();
3499                         break;
3500                 default:
3501                         goto declarator_finished;
3502                 }
3503
3504                 /* insert in the middle of the list (at p) */
3505                 type->base.next = *p;
3506                 *p              = type;
3507                 if (anchor == p)
3508                         anchor = &type->base.next;
3509         }
3510
3511 declarator_finished:
3512         /* append inner_types at the end of the list, we don't to set anchor anymore
3513          * as it's not needed anymore */
3514         *anchor = inner_types;
3515
3516         return first;
3517 }
3518
3519 static type_t *construct_declarator_type(construct_type_t *construct_list,
3520                                          type_t *type)
3521 {
3522         construct_type_t *iter = construct_list;
3523         for (; iter != NULL; iter = iter->base.next) {
3524                 source_position_t const* const pos = &iter->base.pos;
3525                 switch (iter->kind) {
3526                 case CONSTRUCT_FUNCTION: {
3527                         construct_function_type_t *function      = &iter->function;
3528                         type_t                    *function_type = function->function_type;
3529
3530                         function_type->function.return_type = type;
3531
3532                         type_t *skipped_return_type = skip_typeref(type);
3533                         /* §6.7.5.3:1 */
3534                         if (is_type_function(skipped_return_type)) {
3535                                 errorf(pos, "function returning function is not allowed");
3536                         } else if (is_type_array(skipped_return_type)) {
3537                                 errorf(pos, "function returning array is not allowed");
3538                         } else {
3539                                 if (skipped_return_type->base.qualifiers != 0) {
3540                                         warningf(WARN_IGNORED_QUALIFIERS, pos, "type qualifiers in return type of function type are meaningless");
3541                                 }
3542                         }
3543
3544                         /* The function type was constructed earlier.  Freeing it here will
3545                          * destroy other types. */
3546                         type = typehash_insert(function_type);
3547                         continue;
3548                 }
3549
3550                 case CONSTRUCT_POINTER: {
3551                         if (is_type_reference(skip_typeref(type)))
3552                                 errorf(pos, "cannot declare a pointer to reference");
3553
3554                         parsed_pointer_t *pointer = &iter->pointer;
3555                         type = make_based_pointer_type(type, pointer->type_qualifiers, pointer->base_variable);
3556                         continue;
3557                 }
3558
3559                 case CONSTRUCT_REFERENCE:
3560                         if (is_type_reference(skip_typeref(type)))
3561                                 errorf(pos, "cannot declare a reference to reference");
3562
3563                         type = make_reference_type(type);
3564                         continue;
3565
3566                 case CONSTRUCT_ARRAY: {
3567                         if (is_type_reference(skip_typeref(type)))
3568                                 errorf(pos, "cannot declare an array of references");
3569
3570                         parsed_array_t *array      = &iter->array;
3571                         type_t         *array_type = allocate_type_zero(TYPE_ARRAY);
3572
3573                         expression_t *size_expression = array->size;
3574                         if (size_expression != NULL) {
3575                                 size_expression
3576                                         = create_implicit_cast(size_expression, type_size_t);
3577                         }
3578
3579                         array_type->base.qualifiers       = array->type_qualifiers;
3580                         array_type->array.element_type    = type;
3581                         array_type->array.is_static       = array->is_static;
3582                         array_type->array.is_variable     = array->is_variable;
3583                         array_type->array.size_expression = size_expression;
3584
3585                         if (size_expression != NULL) {
3586                                 switch (is_constant_expression(size_expression)) {
3587                                 case EXPR_CLASS_CONSTANT: {
3588                                         long const size = fold_constant_to_int(size_expression);
3589                                         array_type->array.size          = size;
3590                                         array_type->array.size_constant = true;
3591                                         /* §6.7.5.2:1  If the expression is a constant expression,
3592                                          * it shall have a value greater than zero. */
3593                                         if (size < 0) {
3594                                                 errorf(&size_expression->base.source_position,
3595                                                            "size of array must be greater than zero");
3596                                         } else if (size == 0 && !GNU_MODE) {
3597                                                 errorf(&size_expression->base.source_position,
3598                                                            "size of array must be greater than zero (zero length arrays are a GCC extension)");
3599                                         }
3600                                         break;
3601                                 }
3602
3603                                 case EXPR_CLASS_VARIABLE:
3604                                         array_type->array.is_vla = true;
3605                                         break;
3606
3607                                 case EXPR_CLASS_ERROR:
3608                                         break;
3609                                 }
3610                         }
3611
3612                         type_t *skipped_type = skip_typeref(type);
3613                         /* §6.7.5.2:1 */
3614                         if (is_type_incomplete(skipped_type)) {
3615                                 errorf(pos, "array of incomplete type '%T' is not allowed", type);
3616                         } else if (is_type_function(skipped_type)) {
3617                                 errorf(pos, "array of functions is not allowed");
3618                         }
3619                         type = identify_new_type(array_type);
3620                         continue;
3621                 }
3622                 }
3623                 internal_errorf(pos, "invalid type construction found");
3624         }
3625
3626         return type;
3627 }
3628
3629 static type_t *automatic_type_conversion(type_t *orig_type);
3630
3631 static type_t *semantic_parameter(const source_position_t *pos,
3632                                   type_t *type,
3633                                   const declaration_specifiers_t *specifiers,
3634                                   entity_t const *const param)
3635 {
3636         /* §6.7.5.3:7  A declaration of a parameter as ``array of type''
3637          *             shall be adjusted to ``qualified pointer to type'',
3638          *             [...]
3639          * §6.7.5.3:8  A declaration of a parameter as ``function returning
3640          *             type'' shall be adjusted to ``pointer to function
3641          *             returning type'', as in 6.3.2.1. */
3642         type = automatic_type_conversion(type);
3643
3644         if (specifiers->is_inline && is_type_valid(type)) {
3645                 errorf(pos, "'%N' declared 'inline'", param);
3646         }
3647
3648         /* §6.9.1:6  The declarations in the declaration list shall contain
3649          *           no storage-class specifier other than register and no
3650          *           initializations. */
3651         if (specifiers->thread_local || (
3652                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3653                         specifiers->storage_class != STORAGE_CLASS_REGISTER)
3654            ) {
3655                 errorf(pos, "invalid storage class for '%N'", param);
3656         }
3657
3658         /* delay test for incomplete type, because we might have (void)
3659          * which is legal but incomplete... */
3660
3661         return type;
3662 }
3663
3664 static entity_t *parse_declarator(const declaration_specifiers_t *specifiers,
3665                                   declarator_flags_t flags)
3666 {
3667         parse_declarator_env_t env;
3668         memset(&env, 0, sizeof(env));
3669         env.may_be_abstract = (flags & DECL_MAY_BE_ABSTRACT) != 0;
3670
3671         construct_type_t *construct_type = parse_inner_declarator(&env);
3672         type_t           *orig_type      =
3673                 construct_declarator_type(construct_type, specifiers->type);
3674         type_t           *type           = skip_typeref(orig_type);
3675
3676         if (construct_type != NULL) {
3677                 obstack_free(&temp_obst, construct_type);
3678         }
3679
3680         attribute_t *attributes = parse_attributes(env.attributes);
3681         /* append (shared) specifier attribute behind attributes of this
3682          * declarator */
3683         attribute_t **anchor = &attributes;
3684         while (*anchor != NULL)
3685                 anchor = &(*anchor)->next;
3686         *anchor = specifiers->attributes;
3687
3688         entity_t *entity;
3689         if (specifiers->storage_class == STORAGE_CLASS_TYPEDEF) {
3690                 entity = allocate_entity_zero(ENTITY_TYPEDEF, NAMESPACE_NORMAL, env.symbol, &env.source_position);
3691                 entity->typedefe.type = orig_type;
3692
3693                 if (anonymous_entity != NULL) {
3694                         if (is_type_compound(type)) {
3695                                 assert(anonymous_entity->compound.alias == NULL);
3696                                 assert(anonymous_entity->kind == ENTITY_STRUCT ||
3697                                        anonymous_entity->kind == ENTITY_UNION);
3698                                 anonymous_entity->compound.alias = entity;
3699                                 anonymous_entity = NULL;
3700                         } else if (is_type_enum(type)) {
3701                                 assert(anonymous_entity->enume.alias == NULL);
3702                                 assert(anonymous_entity->kind == ENTITY_ENUM);
3703                                 anonymous_entity->enume.alias = entity;
3704                                 anonymous_entity = NULL;
3705                         }
3706                 }
3707         } else {
3708                 /* create a declaration type entity */
3709                 source_position_t const *const pos = env.symbol ? &env.source_position : &specifiers->source_position;
3710                 if (flags & DECL_CREATE_COMPOUND_MEMBER) {
3711                         entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, env.symbol, pos);
3712
3713                         if (env.symbol != NULL) {
3714                                 if (specifiers->is_inline && is_type_valid(type)) {
3715                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3716                                 }
3717
3718                                 if (specifiers->thread_local ||
3719                                                 specifiers->storage_class != STORAGE_CLASS_NONE) {
3720                                         errorf(&env.source_position, "'%N' must have no storage class", entity);
3721                                 }
3722                         }
3723                 } else if (flags & DECL_IS_PARAMETER) {
3724                         entity    = allocate_entity_zero(ENTITY_PARAMETER, NAMESPACE_NORMAL, env.symbol, pos);
3725                         orig_type = semantic_parameter(&env.source_position, orig_type, specifiers, entity);
3726                 } else if (is_type_function(type)) {
3727                         entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, env.symbol, pos);
3728                         entity->function.is_inline      = specifiers->is_inline;
3729                         entity->function.elf_visibility = default_visibility;
3730                         entity->function.parameters     = env.parameters;
3731
3732                         if (env.symbol != NULL) {
3733                                 /* this needs fixes for C++ */
3734                                 bool in_function_scope = current_function != NULL;
3735
3736                                 if (specifiers->thread_local || (
3737                                                         specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3738                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3739                                                         (in_function_scope || specifiers->storage_class != STORAGE_CLASS_STATIC)
3740                                                 )) {
3741                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3742                                 }
3743                         }
3744                 } else {
3745                         entity = allocate_entity_zero(ENTITY_VARIABLE, NAMESPACE_NORMAL, env.symbol, pos);
3746                         entity->variable.elf_visibility = default_visibility;
3747                         entity->variable.thread_local   = specifiers->thread_local;
3748
3749                         if (env.symbol != NULL) {
3750                                 if (specifiers->is_inline && is_type_valid(type)) {
3751                                         errorf(&env.source_position, "'%N' declared 'inline'", entity);
3752                                 }
3753
3754                                 bool invalid_storage_class = false;
3755                                 if (current_scope == file_scope) {
3756                                         if (specifiers->storage_class != STORAGE_CLASS_EXTERN &&
3757                                                         specifiers->storage_class != STORAGE_CLASS_NONE   &&
3758                                                         specifiers->storage_class != STORAGE_CLASS_STATIC) {
3759                                                 invalid_storage_class = true;
3760                                         }
3761                                 } else {
3762                                         if (specifiers->thread_local &&
3763                                                         specifiers->storage_class == STORAGE_CLASS_NONE) {
3764                                                 invalid_storage_class = true;
3765                                         }
3766                                 }
3767                                 if (invalid_storage_class) {
3768                                         errorf(&env.source_position, "invalid storage class for '%N'", entity);
3769                                 }
3770                         }
3771                 }
3772
3773                 entity->declaration.type       = orig_type;
3774                 entity->declaration.alignment  = get_type_alignment(orig_type);
3775                 entity->declaration.modifiers  = env.modifiers;
3776                 entity->declaration.attributes = attributes;
3777
3778                 storage_class_t storage_class = specifiers->storage_class;
3779                 entity->declaration.declared_storage_class = storage_class;
3780
3781                 if (storage_class == STORAGE_CLASS_NONE && current_function != NULL)
3782                         storage_class = STORAGE_CLASS_AUTO;
3783                 entity->declaration.storage_class = storage_class;
3784         }
3785
3786         if (attributes != NULL) {
3787                 handle_entity_attributes(attributes, entity);
3788         }
3789
3790         if (entity->kind == ENTITY_FUNCTION && !freestanding) {
3791                 adapt_special_functions(&entity->function);
3792         }
3793
3794         return entity;
3795 }
3796
3797 static type_t *parse_abstract_declarator(type_t *base_type)
3798 {
3799         parse_declarator_env_t env;
3800         memset(&env, 0, sizeof(env));
3801         env.may_be_abstract = true;
3802         env.must_be_abstract = true;
3803
3804         construct_type_t *construct_type = parse_inner_declarator(&env);
3805
3806         type_t *result = construct_declarator_type(construct_type, base_type);
3807         if (construct_type != NULL) {
3808                 obstack_free(&temp_obst, construct_type);
3809         }
3810         result = handle_type_attributes(env.attributes, result);
3811
3812         return result;
3813 }
3814
3815 /**
3816  * Check if the declaration of main is suspicious.  main should be a
3817  * function with external linkage, returning int, taking either zero
3818  * arguments, two, or three arguments of appropriate types, ie.
3819  *
3820  * int main([ int argc, char **argv [, char **env ] ]).
3821  *
3822  * @param decl    the declaration to check
3823  * @param type    the function type of the declaration
3824  */
3825 static void check_main(const entity_t *entity)
3826 {
3827         const source_position_t *pos = &entity->base.source_position;
3828         if (entity->kind != ENTITY_FUNCTION) {
3829                 warningf(WARN_MAIN, pos, "'main' is not a function");
3830                 return;
3831         }
3832
3833         if (entity->declaration.storage_class == STORAGE_CLASS_STATIC) {
3834                 warningf(WARN_MAIN, pos, "'main' is normally a non-static function");
3835         }
3836
3837         type_t *type = skip_typeref(entity->declaration.type);
3838         assert(is_type_function(type));
3839
3840         function_type_t const *const func_type = &type->function;
3841         type_t                *const ret_type  = func_type->return_type;
3842         if (!types_compatible(skip_typeref(ret_type), type_int)) {
3843                 warningf(WARN_MAIN, pos, "return type of 'main' should be 'int', but is '%T'", ret_type);
3844         }
3845         const function_parameter_t *parm = func_type->parameters;
3846         if (parm != NULL) {
3847                 type_t *const first_type        = skip_typeref(parm->type);
3848                 type_t *const first_type_unqual = get_unqualified_type(first_type);
3849                 if (!types_compatible(first_type_unqual, type_int)) {
3850                         warningf(WARN_MAIN, pos, "first argument of 'main' should be 'int', but is '%T'", parm->type);
3851                 }
3852                 parm = parm->next;
3853                 if (parm != NULL) {
3854                         type_t *const second_type = skip_typeref(parm->type);
3855                         type_t *const second_type_unqual
3856                                 = get_unqualified_type(second_type);
3857                         if (!types_compatible(second_type_unqual, type_char_ptr_ptr)) {
3858                                 warningf(WARN_MAIN, pos, "second argument of 'main' should be 'char**', but is '%T'", parm->type);
3859                         }
3860                         parm = parm->next;
3861                         if (parm != NULL) {
3862                                 type_t *const third_type = skip_typeref(parm->type);
3863                                 type_t *const third_type_unqual
3864                                         = get_unqualified_type(third_type);
3865                                 if (!types_compatible(third_type_unqual, type_char_ptr_ptr)) {
3866                                         warningf(WARN_MAIN, pos, "third argument of 'main' should be 'char**', but is '%T'", parm->type);
3867                                 }
3868                                 parm = parm->next;
3869                                 if (parm != NULL)
3870                                         goto warn_arg_count;
3871                         }
3872                 } else {
3873 warn_arg_count:
3874                         warningf(WARN_MAIN, pos, "'main' takes only zero, two or three arguments");
3875                 }
3876         }
3877 }
3878
3879 static void error_redefined_as_different_kind(const source_position_t *pos,
3880                 const entity_t *old, entity_kind_t new_kind)
3881 {
3882         char              const *const what = get_entity_kind_name(new_kind);
3883         source_position_t const *const ppos = &old->base.source_position;
3884         errorf(pos, "redeclaration of '%N' as %s (declared %P)", old, what, ppos);
3885 }
3886
3887 static bool is_entity_valid(entity_t *const ent)
3888 {
3889         if (is_declaration(ent)) {
3890                 return is_type_valid(skip_typeref(ent->declaration.type));
3891         } else if (ent->kind == ENTITY_TYPEDEF) {
3892                 return is_type_valid(skip_typeref(ent->typedefe.type));
3893         }
3894         return true;
3895 }
3896
3897 static bool contains_attribute(const attribute_t *list, const attribute_t *attr)
3898 {
3899         for (const attribute_t *tattr = list; tattr != NULL; tattr = tattr->next) {
3900                 if (attributes_equal(tattr, attr))
3901                         return true;
3902         }
3903         return false;
3904 }
3905
3906 /**
3907  * test wether new_list contains any attributes not included in old_list
3908  */
3909 static bool has_new_attributes(const attribute_t *old_list,
3910                                const attribute_t *new_list)
3911 {
3912         for (const attribute_t *attr = new_list; attr != NULL; attr = attr->next) {
3913                 if (!contains_attribute(old_list, attr))
3914                         return true;
3915         }
3916         return false;
3917 }
3918
3919 /**
3920  * Merge in attributes from an attribute list (probably from a previous
3921  * declaration with the same name). Warning: destroys the old structure
3922  * of the attribute list - don't reuse attributes after this call.
3923  */
3924 static void merge_in_attributes(declaration_t *decl, attribute_t *attributes)
3925 {
3926         attribute_t *next;
3927         for (attribute_t *attr = attributes; attr != NULL; attr = next) {
3928                 next = attr->next;
3929                 if (contains_attribute(decl->attributes, attr))
3930                         continue;
3931
3932                 /* move attribute to new declarations attributes list */
3933                 attr->next       = decl->attributes;
3934                 decl->attributes = attr;
3935         }
3936 }
3937
3938 static bool is_main(entity_t*);
3939
3940 /**
3941  * record entities for the NAMESPACE_NORMAL, and produce error messages/warnings
3942  * for various problems that occur for multiple definitions
3943  */
3944 entity_t *record_entity(entity_t *entity, const bool is_definition)
3945 {
3946         const symbol_t *const    symbol  = entity->base.symbol;
3947         const namespace_tag_t    namespc = (namespace_tag_t)entity->base.namespc;
3948         const source_position_t *pos     = &entity->base.source_position;
3949
3950         /* can happen in error cases */
3951         if (symbol == NULL)
3952                 return entity;
3953
3954         assert(!entity->base.parent_scope);
3955         assert(current_scope);
3956         entity->base.parent_scope = current_scope;
3957
3958         entity_t *const previous_entity = get_entity(symbol, namespc);
3959         /* pushing the same entity twice will break the stack structure */
3960         assert(previous_entity != entity);
3961
3962         if (entity->kind == ENTITY_FUNCTION) {
3963                 type_t *const orig_type = entity->declaration.type;
3964                 type_t *const type      = skip_typeref(orig_type);
3965
3966                 assert(is_type_function(type));
3967                 if (type->function.unspecified_parameters &&
3968                     previous_entity == NULL               &&
3969                     !entity->declaration.implicit) {
3970                         warningf(WARN_STRICT_PROTOTYPES, pos, "function declaration '%#N' is not a prototype", entity);
3971                 }
3972
3973                 if (is_main(entity)) {
3974                         check_main(entity);
3975                 }
3976         }
3977
3978         if (is_declaration(entity)                                    &&
3979             entity->declaration.storage_class == STORAGE_CLASS_EXTERN &&
3980             current_scope != file_scope                               &&
3981             !entity->declaration.implicit) {
3982                 warningf(WARN_NESTED_EXTERNS, pos, "nested extern declaration of '%#N'", entity);
3983         }
3984
3985         if (previous_entity != NULL) {
3986                 source_position_t const *const ppos = &previous_entity->base.source_position;
3987
3988                 if (previous_entity->base.parent_scope == &current_function->parameters &&
3989                                 previous_entity->base.parent_scope->depth + 1 == current_scope->depth) {
3990                         assert(previous_entity->kind == ENTITY_PARAMETER);
3991                         errorf(pos, "declaration of '%N' redeclares the '%N' (declared %P)", entity, previous_entity, ppos);
3992                         goto finish;
3993                 }
3994
3995                 if (previous_entity->base.parent_scope == current_scope) {
3996                         if (previous_entity->kind != entity->kind) {
3997                                 if (is_entity_valid(previous_entity) && is_entity_valid(entity)) {
3998                                         error_redefined_as_different_kind(pos, previous_entity,
3999                                                         entity->kind);
4000                                 }
4001                                 goto finish;
4002                         }
4003                         if (previous_entity->kind == ENTITY_ENUM_VALUE) {
4004                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4005                                 goto finish;
4006                         }
4007                         if (previous_entity->kind == ENTITY_TYPEDEF) {
4008                                 type_t *const type      = skip_typeref(entity->typedefe.type);
4009                                 type_t *const prev_type
4010                                         = skip_typeref(previous_entity->typedefe.type);
4011                                 if (c_mode & _CXX) {
4012                                         /* C++ allows double typedef if they are identical
4013                                          * (after skipping typedefs) */
4014                                         if (type == prev_type)
4015                                                 goto finish;
4016                                 } else {
4017                                         /* GCC extension: redef in system headers is allowed */
4018                                         if ((pos->is_system_header || ppos->is_system_header) &&
4019                                             types_compatible(type, prev_type))
4020                                                 goto finish;
4021                                 }
4022                                 errorf(pos, "redefinition of '%N' (declared %P)",
4023                                        entity, ppos);
4024                                 goto finish;
4025                         }
4026
4027                         /* at this point we should have only VARIABLES or FUNCTIONS */
4028                         assert(is_declaration(previous_entity) && is_declaration(entity));
4029
4030                         declaration_t *const prev_decl = &previous_entity->declaration;
4031                         declaration_t *const decl      = &entity->declaration;
4032
4033                         /* can happen for K&R style declarations */
4034                         if (prev_decl->type       == NULL             &&
4035                                         previous_entity->kind == ENTITY_PARAMETER &&
4036                                         entity->kind          == ENTITY_PARAMETER) {
4037                                 prev_decl->type                   = decl->type;
4038                                 prev_decl->storage_class          = decl->storage_class;
4039                                 prev_decl->declared_storage_class = decl->declared_storage_class;
4040                                 prev_decl->modifiers              = decl->modifiers;
4041                                 return previous_entity;
4042                         }
4043
4044                         type_t *const type      = skip_typeref(decl->type);
4045                         type_t *const prev_type = skip_typeref(prev_decl->type);
4046
4047                         if (!types_compatible(type, prev_type)) {
4048                                 errorf(pos, "declaration '%#N' is incompatible with '%#N' (declared %P)", entity, previous_entity, ppos);
4049                         } else {
4050                                 unsigned old_storage_class = prev_decl->storage_class;
4051
4052                                 if (is_definition                     &&
4053                                                 !prev_decl->used                  &&
4054                                                 !(prev_decl->modifiers & DM_USED) &&
4055                                                 prev_decl->storage_class == STORAGE_CLASS_STATIC) {
4056                                         warningf(WARN_REDUNDANT_DECLS, ppos, "unnecessary static forward declaration for '%#N'", previous_entity);
4057                                 }
4058
4059                                 storage_class_t new_storage_class = decl->storage_class;
4060
4061                                 /* pretend no storage class means extern for function
4062                                  * declarations (except if the previous declaration is neither
4063                                  * none nor extern) */
4064                                 if (entity->kind == ENTITY_FUNCTION) {
4065                                         /* the previous declaration could have unspecified parameters or
4066                                          * be a typedef, so use the new type */
4067                                         if (prev_type->function.unspecified_parameters || is_definition)
4068                                                 prev_decl->type = type;
4069
4070                                         switch (old_storage_class) {
4071                                                 case STORAGE_CLASS_NONE:
4072                                                         old_storage_class = STORAGE_CLASS_EXTERN;
4073                                                         /* FALLTHROUGH */
4074
4075                                                 case STORAGE_CLASS_EXTERN:
4076                                                         if (is_definition) {
4077                                                                 if (prev_type->function.unspecified_parameters && !is_main(entity)) {
4078                                                                         warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4079                                                                 }
4080                                                         } else if (new_storage_class == STORAGE_CLASS_NONE) {
4081                                                                 new_storage_class = STORAGE_CLASS_EXTERN;
4082                                                         }
4083                                                         break;
4084
4085                                                 default:
4086                                                         break;
4087                                         }
4088                                 } else if (is_type_incomplete(prev_type)) {
4089                                         prev_decl->type = type;
4090                                 }
4091
4092                                 if (old_storage_class == STORAGE_CLASS_EXTERN &&
4093                                                 new_storage_class == STORAGE_CLASS_EXTERN) {
4094
4095 warn_redundant_declaration: ;
4096                                         bool has_new_attrs
4097                                                 = has_new_attributes(prev_decl->attributes,
4098                                                                      decl->attributes);
4099                                         if (has_new_attrs) {
4100                                                 merge_in_attributes(decl, prev_decl->attributes);
4101                                         } else if (!is_definition        &&
4102                                                         is_type_valid(prev_type) &&
4103                                                         !pos->is_system_header) {
4104                                                 warningf(WARN_REDUNDANT_DECLS, pos, "redundant declaration for '%N' (declared %P)", entity, ppos);
4105                                         }
4106                                 } else if (current_function == NULL) {
4107                                         if (old_storage_class != STORAGE_CLASS_STATIC &&
4108                                                         new_storage_class == STORAGE_CLASS_STATIC) {
4109                                                 errorf(pos, "static declaration of '%N' follows non-static declaration (declared %P)", entity, ppos);
4110                                         } else if (old_storage_class == STORAGE_CLASS_EXTERN) {
4111                                                 prev_decl->storage_class          = STORAGE_CLASS_NONE;
4112                                                 prev_decl->declared_storage_class = STORAGE_CLASS_NONE;
4113                                         } else {
4114                                                 /* ISO/IEC 14882:1998(E) §C.1.2:1 */
4115                                                 if (c_mode & _CXX)
4116                                                         goto error_redeclaration;
4117                                                 goto warn_redundant_declaration;
4118                                         }
4119                                 } else if (is_type_valid(prev_type)) {
4120                                         if (old_storage_class == new_storage_class) {
4121 error_redeclaration:
4122                                                 errorf(pos, "redeclaration of '%N' (declared %P)", entity, ppos);
4123                                         } else {
4124                                                 errorf(pos, "redeclaration of '%N' with different linkage (declared %P)", entity, ppos);
4125                                         }
4126                                 }
4127                         }
4128
4129                         prev_decl->modifiers |= decl->modifiers;
4130                         if (entity->kind == ENTITY_FUNCTION) {
4131                                 previous_entity->function.is_inline |= entity->function.is_inline;
4132                         }
4133                         return previous_entity;
4134                 }
4135
4136                 warning_t why;
4137                 if (is_warn_on(why = WARN_SHADOW) ||
4138                     (is_warn_on(why = WARN_SHADOW_LOCAL) && previous_entity->base.parent_scope != file_scope)) {
4139                         char const *const what = get_entity_kind_name(previous_entity->kind);
4140                         warningf(why, pos, "'%N' shadows %s (declared %P)", entity, what, ppos);
4141                 }
4142         }
4143
4144         if (entity->kind == ENTITY_FUNCTION) {
4145                 if (is_definition &&
4146                                 entity->declaration.storage_class != STORAGE_CLASS_STATIC &&
4147                                 !is_main(entity)) {
4148                         if (is_warn_on(WARN_MISSING_PROTOTYPES)) {
4149                                 warningf(WARN_MISSING_PROTOTYPES, pos, "no previous prototype for '%#N'", entity);
4150                         } else {
4151                                 goto warn_missing_declaration;
4152                         }
4153                 }
4154         } else if (entity->kind == ENTITY_VARIABLE) {
4155                 if (current_scope                     == file_scope &&
4156                                 entity->declaration.storage_class == STORAGE_CLASS_NONE &&
4157                                 !entity->declaration.implicit) {
4158 warn_missing_declaration:
4159                         warningf(WARN_MISSING_DECLARATIONS, pos, "no previous declaration for '%#N'", entity);
4160                 }
4161         }
4162
4163 finish:
4164         environment_push(entity);
4165         append_entity(current_scope, entity);
4166
4167         return entity;
4168 }
4169
4170 static void parser_error_multiple_definition(entity_t *entity,
4171                 const source_position_t *source_position)
4172 {
4173         errorf(source_position, "redefinition of '%N' (declared %P)", entity, &entity->base.source_position);
4174 }
4175
4176 static bool is_declaration_specifier(const token_t *token)
4177 {
4178         switch (token->kind) {
4179                 DECLARATION_START
4180                         return true;
4181                 case T_IDENTIFIER:
4182                         return is_typedef_symbol(token->base.symbol);
4183
4184                 default:
4185                         return false;
4186         }
4187 }
4188
4189 static void parse_init_declarator_rest(entity_t *entity)
4190 {
4191         type_t *orig_type = type_error_type;
4192
4193         if (entity->base.kind == ENTITY_TYPEDEF) {
4194                 source_position_t const *const pos = &entity->base.source_position;
4195                 errorf(pos, "'%N' is initialized (use __typeof__ instead)", entity);
4196         } else {
4197                 assert(is_declaration(entity));
4198                 orig_type = entity->declaration.type;
4199         }
4200
4201         type_t *type = skip_typeref(orig_type);
4202
4203         if (entity->kind == ENTITY_VARIABLE
4204                         && entity->variable.initializer != NULL) {
4205                 parser_error_multiple_definition(entity, HERE);
4206         }
4207         eat('=');
4208
4209         declaration_t *const declaration = &entity->declaration;
4210         bool must_be_constant = false;
4211         if (declaration->storage_class == STORAGE_CLASS_STATIC ||
4212             entity->base.parent_scope  == file_scope) {
4213                 must_be_constant = true;
4214         }
4215
4216         if (is_type_function(type)) {
4217                 source_position_t const *const pos = &entity->base.source_position;
4218                 errorf(pos, "'%N' is initialized like a variable", entity);
4219                 orig_type = type_error_type;
4220         }
4221
4222         parse_initializer_env_t env;
4223         env.type             = orig_type;
4224         env.must_be_constant = must_be_constant;
4225         env.entity           = entity;
4226
4227         initializer_t *initializer = parse_initializer(&env);
4228
4229         if (entity->kind == ENTITY_VARIABLE) {
4230                 /* §6.7.5:22  array initializers for arrays with unknown size
4231                  * determine the array type size */
4232                 declaration->type            = env.type;
4233                 entity->variable.initializer = initializer;
4234         }
4235 }
4236
4237 /* parse rest of a declaration without any declarator */
4238 static void parse_anonymous_declaration_rest(
4239                 const declaration_specifiers_t *specifiers)
4240 {
4241         eat(';');
4242         anonymous_entity = NULL;
4243
4244         source_position_t const *const pos = &specifiers->source_position;
4245         if (specifiers->storage_class != STORAGE_CLASS_NONE ||
4246                         specifiers->thread_local) {
4247                 warningf(WARN_OTHER, pos, "useless storage class in empty declaration");
4248         }
4249
4250         type_t *type = specifiers->type;
4251         switch (type->kind) {
4252                 case TYPE_COMPOUND_STRUCT:
4253                 case TYPE_COMPOUND_UNION: {
4254                         if (type->compound.compound->base.symbol == NULL) {
4255                                 warningf(WARN_OTHER, pos, "unnamed struct/union that defines no instances");
4256                         }
4257                         break;
4258                 }
4259
4260                 case TYPE_ENUM:
4261                         break;
4262
4263                 default:
4264                         warningf(WARN_OTHER, pos, "empty declaration");
4265                         break;
4266         }
4267 }
4268
4269 static void check_variable_type_complete(entity_t *ent)
4270 {
4271         if (ent->kind != ENTITY_VARIABLE)
4272                 return;
4273
4274         /* §6.7:7  If an identifier for an object is declared with no linkage, the
4275          *         type for the object shall be complete [...] */
4276         declaration_t *decl = &ent->declaration;
4277         if (decl->storage_class == STORAGE_CLASS_EXTERN ||
4278                         decl->storage_class == STORAGE_CLASS_STATIC)
4279                 return;
4280
4281         type_t *const type = skip_typeref(decl->type);
4282         if (!is_type_incomplete(type))
4283                 return;
4284
4285         /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
4286          * are given length one. */
4287         if (is_type_array(type) && ent->base.parent_scope == file_scope) {
4288                 ARR_APP1(declaration_t*, incomplete_arrays, decl);
4289                 return;
4290         }
4291
4292         errorf(&ent->base.source_position, "variable '%#N' has incomplete type", ent);
4293 }
4294
4295
4296 static void parse_declaration_rest(entity_t *ndeclaration,
4297                 const declaration_specifiers_t *specifiers,
4298                 parsed_declaration_func         finished_declaration,
4299                 declarator_flags_t              flags)
4300 {
4301         add_anchor_token(';');
4302         add_anchor_token(',');
4303         while (true) {
4304                 entity_t *entity = finished_declaration(ndeclaration, token.kind == '=');
4305
4306                 if (token.kind == '=') {
4307                         parse_init_declarator_rest(entity);
4308                 } else if (entity->kind == ENTITY_VARIABLE) {
4309                         /* ISO/IEC 14882:1998(E) §8.5.3:3  The initializer can be omitted
4310                          * [...] where the extern specifier is explicitly used. */
4311                         declaration_t *decl = &entity->declaration;
4312                         if (decl->storage_class != STORAGE_CLASS_EXTERN &&
4313                             is_type_reference(skip_typeref(decl->type))) {
4314                                 source_position_t const *const pos = &entity->base.source_position;
4315                                 errorf(pos, "reference '%#N' must be initialized", entity);
4316                         }
4317                 }
4318
4319                 check_variable_type_complete(entity);
4320
4321                 if (!next_if(','))
4322                         break;
4323
4324                 add_anchor_token('=');
4325                 ndeclaration = parse_declarator(specifiers, flags);
4326                 rem_anchor_token('=');
4327         }
4328         rem_anchor_token(',');
4329         rem_anchor_token(';');
4330         expect(';');
4331
4332         anonymous_entity = NULL;
4333 }
4334
4335 static entity_t *finished_kr_declaration(entity_t *entity, bool is_definition)
4336 {
4337         symbol_t *symbol = entity->base.symbol;
4338         if (symbol == NULL)
4339                 return entity;
4340
4341         assert(entity->base.namespc == NAMESPACE_NORMAL);
4342         entity_t *previous_entity = get_entity(symbol, NAMESPACE_NORMAL);
4343         if (previous_entity == NULL
4344                         || previous_entity->base.parent_scope != current_scope) {
4345                 errorf(&entity->base.source_position, "expected declaration of a function parameter, found '%Y'",
4346                        symbol);
4347                 return entity;
4348         }
4349
4350         if (is_definition) {
4351                 errorf(HERE, "'%N' is initialised", entity);
4352         }
4353
4354         return record_entity(entity, false);
4355 }
4356
4357 static void parse_declaration(parsed_declaration_func finished_declaration,
4358                               declarator_flags_t      flags)
4359 {
4360         add_anchor_token(';');
4361         declaration_specifiers_t specifiers;
4362         parse_declaration_specifiers(&specifiers);
4363         rem_anchor_token(';');
4364
4365         if (token.kind == ';') {
4366                 parse_anonymous_declaration_rest(&specifiers);
4367         } else {
4368                 entity_t *entity = parse_declarator(&specifiers, flags);
4369                 parse_declaration_rest(entity, &specifiers, finished_declaration, flags);
4370         }
4371 }
4372
4373 /* §6.5.2.2:6 */
4374 static type_t *get_default_promoted_type(type_t *orig_type)
4375 {
4376         type_t *result = orig_type;
4377
4378         type_t *type = skip_typeref(orig_type);
4379         if (is_type_integer(type)) {
4380                 result = promote_integer(type);
4381         } else if (is_type_atomic(type, ATOMIC_TYPE_FLOAT)) {
4382                 result = type_double;
4383         }
4384
4385         return result;
4386 }
4387
4388 static void parse_kr_declaration_list(entity_t *entity)
4389 {
4390         if (entity->kind != ENTITY_FUNCTION)
4391                 return;
4392
4393         type_t *type = skip_typeref(entity->declaration.type);
4394         assert(is_type_function(type));
4395         if (!type->function.kr_style_parameters)
4396                 return;
4397
4398         add_anchor_token('{');
4399
4400         PUSH_SCOPE(&entity->function.parameters);
4401
4402         entity_t *parameter = entity->function.parameters.entities;
4403         for ( ; parameter != NULL; parameter = parameter->base.next) {
4404                 assert(parameter->base.parent_scope == NULL);
4405                 parameter->base.parent_scope = current_scope;
4406                 environment_push(parameter);
4407         }
4408
4409         /* parse declaration list */
4410         for (;;) {
4411                 switch (token.kind) {
4412                         DECLARATION_START
4413                         /* This covers symbols, which are no type, too, and results in
4414                          * better error messages.  The typical cases are misspelled type
4415                          * names and missing includes. */
4416                         case T_IDENTIFIER:
4417                                 parse_declaration(finished_kr_declaration, DECL_IS_PARAMETER);
4418                                 break;
4419                         default:
4420                                 goto decl_list_end;
4421                 }
4422         }
4423 decl_list_end:
4424
4425         POP_SCOPE();
4426
4427         /* update function type */
4428         type_t *new_type = duplicate_type(type);
4429
4430         function_parameter_t  *parameters = NULL;
4431         function_parameter_t **anchor     = &parameters;
4432
4433         /* did we have an earlier prototype? */
4434         entity_t *proto_type = get_entity(entity->base.symbol, NAMESPACE_NORMAL);
4435         if (proto_type != NULL && proto_type->kind != ENTITY_FUNCTION)
4436                 proto_type = NULL;
4437
4438         function_parameter_t *proto_parameter = NULL;
4439         if (proto_type != NULL) {
4440                 type_t *proto_type_type = proto_type->declaration.type;
4441                 proto_parameter         = proto_type_type->function.parameters;
4442                 /* If a K&R function definition has a variadic prototype earlier, then
4443                  * make the function definition variadic, too. This should conform to
4444                  * §6.7.5.3:15 and §6.9.1:8. */
4445                 new_type->function.variadic = proto_type_type->function.variadic;
4446         } else {
4447                 /* §6.9.1.7: A K&R style parameter list does NOT act as a function
4448                  * prototype */
4449                 new_type->function.unspecified_parameters = true;
4450         }
4451
4452         bool need_incompatible_warning = false;
4453         parameter = entity->function.parameters.entities;
4454         for (; parameter != NULL; parameter = parameter->base.next,
4455                         proto_parameter =
4456                                 proto_parameter == NULL ? NULL : proto_parameter->next) {
4457                 if (parameter->kind != ENTITY_PARAMETER)
4458                         continue;
4459
4460                 type_t *parameter_type = parameter->declaration.type;
4461                 if (parameter_type == NULL) {
4462                         source_position_t const* const pos = &parameter->base.source_position;
4463                         if (strict_mode) {
4464                                 errorf(pos, "no type specified for function '%N'", parameter);
4465                                 parameter_type = type_error_type;
4466                         } else {
4467                                 warningf(WARN_IMPLICIT_INT, pos, "no type specified for function parameter '%N', using 'int'", parameter);
4468                                 parameter_type = type_int;
4469                         }
4470                         parameter->declaration.type = parameter_type;
4471                 }
4472
4473                 semantic_parameter_incomplete(parameter);
4474
4475                 /* we need the default promoted types for the function type */
4476                 type_t *not_promoted = parameter_type;
4477                 parameter_type       = get_default_promoted_type(parameter_type);
4478
4479                 /* gcc special: if the type of the prototype matches the unpromoted
4480                  * type don't promote */
4481                 if (!strict_mode && proto_parameter != NULL) {
4482                         type_t *proto_p_type = skip_typeref(proto_parameter->type);
4483                         type_t *promo_skip   = skip_typeref(parameter_type);
4484                         type_t *param_skip   = skip_typeref(not_promoted);
4485                         if (!types_compatible(proto_p_type, promo_skip)
4486                                 && types_compatible(proto_p_type, param_skip)) {
4487                                 /* don't promote */
4488                                 need_incompatible_warning = true;
4489                                 parameter_type = not_promoted;
4490                         }
4491                 }
4492                 function_parameter_t *const function_parameter
4493                         = allocate_parameter(parameter_type);
4494
4495                 *anchor = function_parameter;
4496                 anchor  = &function_parameter->next;
4497         }
4498
4499         new_type->function.parameters = parameters;
4500         new_type = identify_new_type(new_type);
4501
4502         if (need_incompatible_warning) {
4503                 symbol_t          const *const sym  = entity->base.symbol;
4504                 source_position_t const *const pos  = &entity->base.source_position;
4505                 source_position_t const *const ppos = &proto_type->base.source_position;
4506                 warningf(WARN_OTHER, pos, "declaration '%#N' is incompatible with '%#T' (declared %P)", proto_type, new_type, sym, ppos);
4507         }
4508         entity->declaration.type = new_type;
4509
4510         rem_anchor_token('{');
4511 }
4512
4513 static bool first_err = true;
4514
4515 /**
4516  * When called with first_err set, prints the name of the current function,
4517  * else does noting.
4518  */
4519 static void print_in_function(void)
4520 {
4521         if (first_err) {
4522                 first_err = false;
4523                 char const *const file = current_function->base.base.source_position.input_name;
4524                 diagnosticf("%s: In '%N':\n", file, (entity_t const*)current_function);
4525         }
4526 }
4527
4528 /**
4529  * Check if all labels are defined in the current function.
4530  * Check if all labels are used in the current function.
4531  */
4532 static void check_labels(void)
4533 {
4534         for (const goto_statement_t *goto_statement = goto_first;
4535             goto_statement != NULL;
4536             goto_statement = goto_statement->next) {
4537                 label_t *label = goto_statement->label;
4538                 if (label->base.source_position.input_name == NULL) {
4539                         print_in_function();
4540                         source_position_t const *const pos = &goto_statement->base.source_position;
4541                         errorf(pos, "'%N' used but not defined", (entity_t const*)label);
4542                  }
4543         }
4544
4545         if (is_warn_on(WARN_UNUSED_LABEL)) {
4546                 for (const label_statement_t *label_statement = label_first;
4547                          label_statement != NULL;
4548                          label_statement = label_statement->next) {
4549                         label_t *label = label_statement->label;
4550
4551                         if (! label->used) {
4552                                 print_in_function();
4553                                 source_position_t const *const pos = &label_statement->base.source_position;
4554                                 warningf(WARN_UNUSED_LABEL, pos, "'%N' defined but not used", (entity_t const*)label);
4555                         }
4556                 }
4557         }
4558 }
4559
4560 static void warn_unused_entity(warning_t const why, entity_t *entity, entity_t *const last)
4561 {
4562         entity_t const *const end = last != NULL ? last->base.next : NULL;
4563         for (; entity != end; entity = entity->base.next) {
4564                 if (!is_declaration(entity))
4565                         continue;
4566
4567                 declaration_t *declaration = &entity->declaration;
4568                 if (declaration->implicit)
4569                         continue;
4570
4571                 if (!declaration->used) {
4572                         print_in_function();
4573                         warningf(why, &entity->base.source_position, "'%N' is unused", entity);
4574                 } else if (entity->kind == ENTITY_VARIABLE && !entity->variable.read) {
4575                         print_in_function();
4576                         warningf(why, &entity->base.source_position, "'%N' is never read", entity);
4577                 }
4578         }
4579 }
4580
4581 static void check_unused_variables(statement_t *const stmt, void *const env)
4582 {
4583         (void)env;
4584
4585         switch (stmt->kind) {
4586                 case STATEMENT_DECLARATION: {
4587                         declaration_statement_t const *const decls = &stmt->declaration;
4588                         warn_unused_entity(WARN_UNUSED_VARIABLE, decls->declarations_begin, decls->declarations_end);
4589                         return;
4590                 }
4591
4592                 case STATEMENT_FOR:
4593                         warn_unused_entity(WARN_UNUSED_VARIABLE, stmt->fors.scope.entities, NULL);
4594                         return;
4595
4596                 default:
4597                         return;
4598         }
4599 }
4600
4601 /**
4602  * Check declarations of current_function for unused entities.
4603  */
4604 static void check_declarations(void)
4605 {
4606         if (is_warn_on(WARN_UNUSED_PARAMETER)) {
4607                 const scope_t *scope = &current_function->parameters;
4608                 warn_unused_entity(WARN_UNUSED_PARAMETER, scope->entities, NULL);
4609         }
4610         if (is_warn_on(WARN_UNUSED_VARIABLE)) {
4611                 walk_statements(current_function->statement, check_unused_variables,
4612                                 NULL);
4613         }
4614 }
4615
4616 static int determine_truth(expression_t const* const cond)
4617 {
4618         return
4619                 is_constant_expression(cond) != EXPR_CLASS_CONSTANT ? 0 :
4620                 fold_constant_to_bool(cond)                         ? 1 :
4621                 -1;
4622 }
4623
4624 static void check_reachable(statement_t *);
4625 static bool reaches_end;
4626
4627 static bool expression_returns(expression_t const *const expr)
4628 {
4629         switch (expr->kind) {
4630                 case EXPR_CALL: {
4631                         expression_t const *const func = expr->call.function;
4632                         type_t       const *const type = skip_typeref(func->base.type);
4633                         if (type->kind == TYPE_POINTER) {
4634                                 type_t const *const points_to
4635                                         = skip_typeref(type->pointer.points_to);
4636                                 if (points_to->kind == TYPE_FUNCTION
4637                                     && points_to->function.modifiers & DM_NORETURN)
4638                                         return false;
4639                         }
4640
4641                         if (!expression_returns(func))
4642                                 return false;
4643
4644                         for (call_argument_t const* arg = expr->call.arguments; arg != NULL; arg = arg->next) {
4645                                 if (!expression_returns(arg->expression))
4646                                         return false;
4647                         }
4648
4649                         return true;
4650                 }
4651
4652                 case EXPR_REFERENCE:
4653                 case EXPR_ENUM_CONSTANT:
4654                 case EXPR_LITERAL_CASES:
4655                 case EXPR_LITERAL_CHARACTER:
4656                 case EXPR_LITERAL_WIDE_CHARACTER:
4657                 case EXPR_STRING_LITERAL:
4658                 case EXPR_COMPOUND_LITERAL: // TODO descend into initialisers
4659                 case EXPR_LABEL_ADDRESS:
4660                 case EXPR_CLASSIFY_TYPE:
4661                 case EXPR_SIZEOF: // TODO handle obscure VLA case
4662                 case EXPR_ALIGNOF:
4663                 case EXPR_FUNCNAME:
4664                 case EXPR_BUILTIN_CONSTANT_P:
4665                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P:
4666                 case EXPR_OFFSETOF:
4667                 case EXPR_ERROR:
4668                         return true;
4669
4670                 case EXPR_STATEMENT: {
4671                         bool old_reaches_end = reaches_end;
4672                         reaches_end = false;
4673                         check_reachable(expr->statement.statement);
4674                         bool returns = reaches_end;
4675                         reaches_end = old_reaches_end;
4676                         return returns;
4677                 }
4678
4679                 case EXPR_CONDITIONAL:
4680                         // TODO handle constant expression
4681
4682                         if (!expression_returns(expr->conditional.condition))
4683                                 return false;
4684
4685                         if (expr->conditional.true_expression != NULL
4686                                         && expression_returns(expr->conditional.true_expression))
4687                                 return true;
4688
4689                         return expression_returns(expr->conditional.false_expression);
4690
4691                 case EXPR_SELECT:
4692                         return expression_returns(expr->select.compound);
4693
4694                 case EXPR_ARRAY_ACCESS:
4695                         return
4696                                 expression_returns(expr->array_access.array_ref) &&
4697                                 expression_returns(expr->array_access.index);
4698
4699                 case EXPR_VA_START:
4700                         return expression_returns(expr->va_starte.ap);
4701
4702                 case EXPR_VA_ARG:
4703                         return expression_returns(expr->va_arge.ap);
4704
4705                 case EXPR_VA_COPY:
4706                         return expression_returns(expr->va_copye.src);
4707
4708                 case EXPR_UNARY_CASES_MANDATORY:
4709                         return expression_returns(expr->unary.value);
4710
4711                 case EXPR_UNARY_THROW:
4712                         return false;
4713
4714                 case EXPR_BINARY_CASES:
4715                         // TODO handle constant lhs of && and ||
4716                         return
4717                                 expression_returns(expr->binary.left) &&
4718                                 expression_returns(expr->binary.right);
4719         }
4720
4721         panic("unhandled expression");
4722 }
4723
4724 static bool initializer_returns(initializer_t const *const init)
4725 {
4726         switch (init->kind) {
4727                 case INITIALIZER_VALUE:
4728                         return expression_returns(init->value.value);
4729
4730                 case INITIALIZER_LIST: {
4731                         initializer_t * const*       i       = init->list.initializers;
4732                         initializer_t * const* const end     = i + init->list.len;
4733                         bool                         returns = true;
4734                         for (; i != end; ++i) {
4735                                 if (!initializer_returns(*i))
4736                                         returns = false;
4737                         }
4738                         return returns;
4739                 }
4740
4741                 case INITIALIZER_STRING:
4742                 case INITIALIZER_WIDE_STRING:
4743                 case INITIALIZER_DESIGNATOR: // designators have no payload
4744                         return true;
4745         }
4746         panic("unhandled initializer");
4747 }
4748
4749 static bool noreturn_candidate;
4750
4751 static void check_reachable(statement_t *const stmt)
4752 {
4753         if (stmt->base.reachable)
4754                 return;
4755         if (stmt->kind != STATEMENT_DO_WHILE)
4756                 stmt->base.reachable = true;
4757
4758         statement_t *last = stmt;
4759         statement_t *next;
4760         switch (stmt->kind) {
4761                 case STATEMENT_ERROR:
4762                 case STATEMENT_EMPTY:
4763                 case STATEMENT_ASM:
4764                         next = stmt->base.next;
4765                         break;
4766
4767                 case STATEMENT_DECLARATION: {
4768                         declaration_statement_t const *const decl = &stmt->declaration;
4769                         entity_t                const *      ent  = decl->declarations_begin;
4770                         entity_t                const *const last_decl = decl->declarations_end;
4771                         if (ent != NULL) {
4772                                 for (;; ent = ent->base.next) {
4773                                         if (ent->kind                 == ENTITY_VARIABLE &&
4774                                             ent->variable.initializer != NULL            &&
4775                                             !initializer_returns(ent->variable.initializer)) {
4776                                                 return;
4777                                         }
4778                                         if (ent == last_decl)
4779                                                 break;
4780                                 }
4781                         }
4782                         next = stmt->base.next;
4783                         break;
4784                 }
4785
4786                 case STATEMENT_COMPOUND:
4787                         next = stmt->compound.statements;
4788                         if (next == NULL)
4789                                 next = stmt->base.next;
4790                         break;
4791
4792                 case STATEMENT_RETURN: {
4793                         expression_t const *const val = stmt->returns.value;
4794                         if (val == NULL || expression_returns(val))
4795                                 noreturn_candidate = false;
4796                         return;
4797                 }
4798
4799                 case STATEMENT_IF: {
4800                         if_statement_t const *const ifs  = &stmt->ifs;
4801                         expression_t   const *const cond = ifs->condition;
4802
4803                         if (!expression_returns(cond))
4804                                 return;
4805
4806                         int const val = determine_truth(cond);
4807
4808                         if (val >= 0)
4809                                 check_reachable(ifs->true_statement);
4810
4811                         if (val > 0)
4812                                 return;
4813
4814                         if (ifs->false_statement != NULL) {
4815                                 check_reachable(ifs->false_statement);
4816                                 return;
4817                         }
4818
4819                         next = stmt->base.next;
4820                         break;
4821                 }
4822
4823                 case STATEMENT_SWITCH: {
4824                         switch_statement_t const *const switchs = &stmt->switchs;
4825                         expression_t       const *const expr    = switchs->expression;
4826
4827                         if (!expression_returns(expr))
4828                                 return;
4829
4830                         if (is_constant_expression(expr) == EXPR_CLASS_CONSTANT) {
4831                                 long                    const val      = fold_constant_to_int(expr);
4832                                 case_label_statement_t *      defaults = NULL;
4833                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4834                                         if (i->expression == NULL) {
4835                                                 defaults = i;
4836                                                 continue;
4837                                         }
4838
4839                                         if (i->first_case <= val && val <= i->last_case) {
4840                                                 check_reachable((statement_t*)i);
4841                                                 return;
4842                                         }
4843                                 }
4844
4845                                 if (defaults != NULL) {
4846                                         check_reachable((statement_t*)defaults);
4847                                         return;
4848                                 }
4849                         } else {
4850                                 bool has_default = false;
4851                                 for (case_label_statement_t *i = switchs->first_case; i != NULL; i = i->next) {
4852                                         if (i->expression == NULL)
4853                                                 has_default = true;
4854
4855                                         check_reachable((statement_t*)i);
4856                                 }
4857
4858                                 if (has_default)
4859                                         return;
4860                         }
4861
4862                         next = stmt->base.next;
4863                         break;
4864                 }
4865
4866                 case STATEMENT_EXPRESSION: {
4867                         /* Check for noreturn function call */
4868                         expression_t const *const expr = stmt->expression.expression;
4869                         if (!expression_returns(expr))
4870                                 return;
4871
4872                         next = stmt->base.next;
4873                         break;
4874                 }
4875
4876                 case STATEMENT_CONTINUE:
4877                         for (statement_t *parent = stmt;;) {
4878                                 parent = parent->base.parent;
4879                                 if (parent == NULL) /* continue not within loop */
4880                                         return;
4881
4882                                 next = parent;
4883                                 switch (parent->kind) {
4884                                         case STATEMENT_WHILE:    goto continue_while;
4885                                         case STATEMENT_DO_WHILE: goto continue_do_while;
4886                                         case STATEMENT_FOR:      goto continue_for;
4887
4888                                         default: break;
4889                                 }
4890                         }
4891
4892                 case STATEMENT_BREAK:
4893                         for (statement_t *parent = stmt;;) {
4894                                 parent = parent->base.parent;
4895                                 if (parent == NULL) /* break not within loop/switch */
4896                                         return;
4897
4898                                 switch (parent->kind) {
4899                                         case STATEMENT_SWITCH:
4900                                         case STATEMENT_WHILE:
4901                                         case STATEMENT_DO_WHILE:
4902                                         case STATEMENT_FOR:
4903                                                 last = parent;
4904                                                 next = parent->base.next;
4905                                                 goto found_break_parent;
4906
4907                                         default: break;
4908                                 }
4909                         }
4910 found_break_parent:
4911                         break;
4912
4913                 case STATEMENT_COMPUTED_GOTO: {
4914                         if (!expression_returns(stmt->computed_goto.expression))
4915                                 return;
4916
4917                         statement_t *parent = stmt->base.parent;
4918                         if (parent == NULL) /* top level goto */
4919                                 return;
4920                         next = parent;
4921                         break;
4922                 }
4923
4924                 case STATEMENT_GOTO:
4925                         next = stmt->gotos.label->statement;
4926                         if (next == NULL) /* missing label */
4927                                 return;
4928                         break;
4929
4930                 case STATEMENT_LABEL:
4931                         next = stmt->label.statement;
4932                         break;
4933
4934                 case STATEMENT_CASE_LABEL:
4935                         next = stmt->case_label.statement;
4936                         break;
4937
4938                 case STATEMENT_WHILE: {
4939                         while_statement_t const *const whiles = &stmt->whiles;
4940                         expression_t      const *const cond   = whiles->condition;
4941
4942                         if (!expression_returns(cond))
4943                                 return;
4944
4945                         int const val = determine_truth(cond);
4946
4947                         if (val >= 0)
4948                                 check_reachable(whiles->body);
4949
4950                         if (val > 0)
4951                                 return;
4952
4953                         next = stmt->base.next;
4954                         break;
4955                 }
4956
4957                 case STATEMENT_DO_WHILE:
4958                         next = stmt->do_while.body;
4959                         break;
4960
4961                 case STATEMENT_FOR: {
4962                         for_statement_t *const fors = &stmt->fors;
4963
4964                         if (fors->condition_reachable)
4965                                 return;
4966                         fors->condition_reachable = true;
4967
4968                         expression_t const *const cond = fors->condition;
4969
4970                         int val;
4971                         if (cond == NULL) {
4972                                 val = 1;
4973                         } else if (expression_returns(cond)) {
4974                                 val = determine_truth(cond);
4975                         } else {
4976                                 return;
4977                         }
4978
4979                         if (val >= 0)
4980                                 check_reachable(fors->body);
4981
4982                         if (val > 0)
4983                                 return;
4984
4985                         next = stmt->base.next;
4986                         break;
4987                 }
4988
4989                 case STATEMENT_MS_TRY: {
4990                         ms_try_statement_t const *const ms_try = &stmt->ms_try;
4991                         check_reachable(ms_try->try_statement);
4992                         next = ms_try->final_statement;
4993                         break;
4994                 }
4995
4996                 case STATEMENT_LEAVE: {
4997                         statement_t *parent = stmt;
4998                         for (;;) {
4999                                 parent = parent->base.parent;
5000                                 if (parent == NULL) /* __leave not within __try */
5001                                         return;
5002
5003                                 if (parent->kind == STATEMENT_MS_TRY) {
5004                                         last = parent;
5005                                         next = parent->ms_try.final_statement;
5006                                         break;
5007                                 }
5008                         }
5009                         break;
5010                 }
5011
5012                 default:
5013                         panic("invalid statement kind");
5014         }
5015
5016         while (next == NULL) {
5017                 next = last->base.parent;
5018                 if (next == NULL) {
5019                         noreturn_candidate = false;
5020
5021                         type_t *const type = skip_typeref(current_function->base.type);
5022                         assert(is_type_function(type));
5023                         type_t *const ret  = skip_typeref(type->function.return_type);
5024                         if (!is_type_void(ret) &&
5025                             is_type_valid(ret) &&
5026                             !is_main(current_entity)) {
5027                                 source_position_t const *const pos = &stmt->base.source_position;
5028                                 warningf(WARN_RETURN_TYPE, pos, "control reaches end of non-void function");
5029                         }
5030                         return;
5031                 }
5032
5033                 switch (next->kind) {
5034                         case STATEMENT_ERROR:
5035                         case STATEMENT_EMPTY:
5036                         case STATEMENT_DECLARATION:
5037                         case STATEMENT_EXPRESSION:
5038                         case STATEMENT_ASM:
5039                         case STATEMENT_RETURN:
5040                         case STATEMENT_CONTINUE:
5041                         case STATEMENT_BREAK:
5042                         case STATEMENT_COMPUTED_GOTO:
5043                         case STATEMENT_GOTO:
5044                         case STATEMENT_LEAVE:
5045                                 panic("invalid control flow in function");
5046
5047                         case STATEMENT_COMPOUND:
5048                                 if (next->compound.stmt_expr) {
5049                                         reaches_end = true;
5050                                         return;
5051                                 }
5052                                 /* FALLTHROUGH */
5053                         case STATEMENT_IF:
5054                         case STATEMENT_SWITCH:
5055                         case STATEMENT_LABEL:
5056                         case STATEMENT_CASE_LABEL:
5057                                 last = next;
5058                                 next = next->base.next;
5059                                 break;
5060
5061                         case STATEMENT_WHILE: {
5062 continue_while:
5063                                 if (next->base.reachable)
5064                                         return;
5065                                 next->base.reachable = true;
5066
5067                                 while_statement_t const *const whiles = &next->whiles;
5068                                 expression_t      const *const cond   = whiles->condition;
5069
5070                                 if (!expression_returns(cond))
5071                                         return;
5072
5073                                 int const val = determine_truth(cond);
5074
5075                                 if (val >= 0)
5076                                         check_reachable(whiles->body);
5077
5078                                 if (val > 0)
5079                                         return;
5080
5081                                 last = next;
5082                                 next = next->base.next;
5083                                 break;
5084                         }
5085
5086                         case STATEMENT_DO_WHILE: {
5087 continue_do_while:
5088                                 if (next->base.reachable)
5089                                         return;
5090                                 next->base.reachable = true;
5091
5092                                 do_while_statement_t const *const dw   = &next->do_while;
5093                                 expression_t         const *const cond = dw->condition;
5094
5095                                 if (!expression_returns(cond))
5096                                         return;
5097
5098                                 int const val = determine_truth(cond);
5099
5100                                 if (val >= 0)
5101                                         check_reachable(dw->body);
5102
5103                                 if (val > 0)
5104                                         return;
5105
5106                                 last = next;
5107                                 next = next->base.next;
5108                                 break;
5109                         }
5110
5111                         case STATEMENT_FOR: {
5112 continue_for:;
5113                                 for_statement_t *const fors = &next->fors;
5114
5115                                 fors->step_reachable = true;
5116
5117                                 if (fors->condition_reachable)
5118                                         return;
5119                                 fors->condition_reachable = true;
5120
5121                                 expression_t const *const cond = fors->condition;
5122
5123                                 int val;
5124                                 if (cond == NULL) {
5125                                         val = 1;
5126                                 } else if (expression_returns(cond)) {
5127                                         val = determine_truth(cond);
5128                                 } else {
5129                                         return;
5130                                 }
5131
5132                                 if (val >= 0)
5133                                         check_reachable(fors->body);
5134
5135                                 if (val > 0)
5136                                         return;
5137
5138                                 last = next;
5139                                 next = next->base.next;
5140                                 break;
5141                         }
5142
5143                         case STATEMENT_MS_TRY:
5144                                 last = next;
5145                                 next = next->ms_try.final_statement;
5146                                 break;
5147                 }
5148         }
5149
5150         check_reachable(next);
5151 }
5152
5153 static void check_unreachable(statement_t* const stmt, void *const env)
5154 {
5155         (void)env;
5156
5157         switch (stmt->kind) {
5158                 case STATEMENT_DO_WHILE:
5159                         if (!stmt->base.reachable) {
5160                                 expression_t const *const cond = stmt->do_while.condition;
5161                                 if (determine_truth(cond) >= 0) {
5162                                         source_position_t const *const pos = &cond->base.source_position;
5163                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of do-while-loop is unreachable");
5164                                 }
5165                         }
5166                         return;
5167
5168                 case STATEMENT_FOR: {
5169                         for_statement_t const* const fors = &stmt->fors;
5170
5171                         // if init and step are unreachable, cond is unreachable, too
5172                         if (!stmt->base.reachable && !fors->step_reachable) {
5173                                 goto warn_unreachable;
5174                         } else {
5175                                 if (!stmt->base.reachable && fors->initialisation != NULL) {
5176                                         source_position_t const *const pos = &fors->initialisation->base.source_position;
5177                                         warningf(WARN_UNREACHABLE_CODE, pos, "initialisation of for-statement is unreachable");
5178                                 }
5179
5180                                 if (!fors->condition_reachable && fors->condition != NULL) {
5181                                         source_position_t const *const pos = &fors->condition->base.source_position;
5182                                         warningf(WARN_UNREACHABLE_CODE, pos, "condition of for-statement is unreachable");
5183                                 }
5184
5185                                 if (!fors->step_reachable && fors->step != NULL) {
5186                                         source_position_t const *const pos = &fors->step->base.source_position;
5187                                         warningf(WARN_UNREACHABLE_CODE, pos, "step of for-statement is unreachable");
5188                                 }
5189                         }
5190                         return;
5191                 }
5192
5193                 case STATEMENT_COMPOUND:
5194                         if (stmt->compound.statements != NULL)
5195                                 return;
5196                         goto warn_unreachable;
5197
5198                 case STATEMENT_DECLARATION: {
5199                         /* Only warn if there is at least one declarator with an initializer.
5200                          * This typically occurs in switch statements. */
5201                         declaration_statement_t const *const decl = &stmt->declaration;
5202                         entity_t                const *      ent  = decl->declarations_begin;
5203                         entity_t                const *const last = decl->declarations_end;
5204                         if (ent != NULL) {
5205                                 for (;; ent = ent->base.next) {
5206                                         if (ent->kind                 == ENTITY_VARIABLE &&
5207                                                         ent->variable.initializer != NULL) {
5208                                                 goto warn_unreachable;
5209                                         }
5210                                         if (ent == last)
5211                                                 return;
5212                                 }
5213                         }
5214                 }
5215
5216                 default:
5217 warn_unreachable:
5218                         if (!stmt->base.reachable) {
5219                                 source_position_t const *const pos = &stmt->base.source_position;
5220                                 warningf(WARN_UNREACHABLE_CODE, pos, "statement is unreachable");
5221                         }
5222                         return;
5223         }
5224 }
5225
5226 static bool is_main(entity_t *entity)
5227 {
5228         static symbol_t *sym_main = NULL;
5229         if (sym_main == NULL) {
5230                 sym_main = symbol_table_insert("main");
5231         }
5232
5233         if (entity->base.symbol != sym_main)
5234                 return false;
5235         /* must be in outermost scope */
5236         if (entity->base.parent_scope != file_scope)
5237                 return false;
5238
5239         return true;
5240 }
5241
5242 static void prepare_main_collect2(entity_t*);
5243
5244 static void parse_external_declaration(void)
5245 {
5246         /* function-definitions and declarations both start with declaration
5247          * specifiers */
5248         add_anchor_token(';');
5249         declaration_specifiers_t specifiers;
5250         parse_declaration_specifiers(&specifiers);
5251         rem_anchor_token(';');
5252
5253         /* must be a declaration */
5254         if (token.kind == ';') {
5255                 parse_anonymous_declaration_rest(&specifiers);
5256                 return;
5257         }
5258
5259         add_anchor_token(',');
5260         add_anchor_token('=');
5261         add_anchor_token(';');
5262         add_anchor_token('{');
5263
5264         /* declarator is common to both function-definitions and declarations */
5265         entity_t *ndeclaration = parse_declarator(&specifiers, DECL_FLAGS_NONE);
5266
5267         rem_anchor_token('{');
5268         rem_anchor_token(';');
5269         rem_anchor_token('=');
5270         rem_anchor_token(',');
5271
5272         /* must be a declaration */
5273         switch (token.kind) {
5274                 case ',':
5275                 case ';':
5276                 case '=':
5277                         parse_declaration_rest(ndeclaration, &specifiers, record_entity,
5278                                         DECL_FLAGS_NONE);
5279                         return;
5280         }
5281
5282         /* must be a function definition */
5283         parse_kr_declaration_list(ndeclaration);
5284
5285         if (token.kind != '{') {
5286                 parse_error_expected("while parsing function definition", '{', NULL);
5287                 eat_until_matching_token(';');
5288                 return;
5289         }
5290
5291         assert(is_declaration(ndeclaration));
5292         type_t *const orig_type = ndeclaration->declaration.type;
5293         type_t *      type      = skip_typeref(orig_type);
5294
5295         if (!is_type_function(type)) {
5296                 if (is_type_valid(type)) {
5297                         errorf(HERE, "declarator '%#N' has a body but is not a function type", ndeclaration);
5298                 }
5299                 eat_block();
5300                 return;
5301         }
5302
5303         source_position_t const *const pos = &ndeclaration->base.source_position;
5304         if (is_typeref(orig_type)) {
5305                 /* §6.9.1:2 */
5306                 errorf(pos, "type of function definition '%#N' is a typedef", ndeclaration);
5307         }
5308
5309         if (is_type_compound(skip_typeref(type->function.return_type))) {
5310                 warningf(WARN_AGGREGATE_RETURN, pos, "'%N' returns an aggregate", ndeclaration);
5311         }
5312         if (type->function.unspecified_parameters) {
5313                 warningf(WARN_OLD_STYLE_DEFINITION, pos, "old-style definition of '%N'", ndeclaration);
5314         } else {
5315                 warningf(WARN_TRADITIONAL, pos, "traditional C rejects ISO C style definition of '%N'", ndeclaration);
5316         }
5317
5318         /* §6.7.5.3:14 a function definition with () means no
5319          * parameters (and not unspecified parameters) */
5320         if (type->function.unspecified_parameters &&
5321                         type->function.parameters == NULL) {
5322                 type_t *copy                          = duplicate_type(type);
5323                 copy->function.unspecified_parameters = false;
5324                 type                                  = identify_new_type(copy);
5325
5326                 ndeclaration->declaration.type = type;
5327         }
5328
5329         entity_t *const entity = record_entity(ndeclaration, true);
5330         assert(entity->kind == ENTITY_FUNCTION);
5331         assert(ndeclaration->kind == ENTITY_FUNCTION);
5332
5333         function_t *const function = &entity->function;
5334         if (ndeclaration != entity) {
5335                 function->parameters = ndeclaration->function.parameters;
5336         }
5337
5338         PUSH_SCOPE(&function->parameters);
5339
5340         entity_t *parameter = function->parameters.entities;
5341         for (; parameter != NULL; parameter = parameter->base.next) {
5342                 if (parameter->base.parent_scope == &ndeclaration->function.parameters) {
5343                         parameter->base.parent_scope = current_scope;
5344                 }
5345                 assert(parameter->base.parent_scope == NULL
5346                                 || parameter->base.parent_scope == current_scope);
5347                 parameter->base.parent_scope = current_scope;
5348                 if (parameter->base.symbol == NULL) {
5349                         errorf(&parameter->base.source_position, "parameter name omitted");
5350                         continue;
5351                 }
5352                 environment_push(parameter);
5353         }
5354
5355         if (function->statement != NULL) {
5356                 parser_error_multiple_definition(entity, HERE);
5357                 eat_block();
5358         } else {
5359                 /* parse function body */
5360                 int         label_stack_top      = label_top();
5361                 function_t *old_current_function = current_function;
5362                 current_function                 = function;
5363                 PUSH_CURRENT_ENTITY(entity);
5364                 PUSH_PARENT(NULL);
5365
5366                 goto_first   = NULL;
5367                 goto_anchor  = &goto_first;
5368                 label_first  = NULL;
5369                 label_anchor = &label_first;
5370
5371                 statement_t *const body = parse_compound_statement(false);
5372                 function->statement = body;
5373                 first_err = true;
5374                 check_labels();
5375                 check_declarations();
5376                 if (is_warn_on(WARN_RETURN_TYPE)      ||
5377                     is_warn_on(WARN_UNREACHABLE_CODE) ||
5378                     (is_warn_on(WARN_MISSING_NORETURN) && !(function->base.modifiers & DM_NORETURN))) {
5379                         noreturn_candidate = true;
5380                         check_reachable(body);
5381                         if (is_warn_on(WARN_UNREACHABLE_CODE))
5382                                 walk_statements(body, check_unreachable, NULL);
5383                         if (noreturn_candidate &&
5384                             !(function->base.modifiers & DM_NORETURN)) {
5385                                 source_position_t const *const pos = &body->base.source_position;
5386                                 warningf(WARN_MISSING_NORETURN, pos, "function '%#N' is candidate for attribute 'noreturn'", entity);
5387                         }
5388                 }
5389
5390                 if (is_main(entity)) {
5391                         /* Force main to C linkage. */
5392                         type_t *const type = entity->declaration.type;
5393                         assert(is_type_function(type));
5394                         if (type->function.linkage != LINKAGE_C) {
5395                                 type_t *new_type           = duplicate_type(type);
5396                                 new_type->function.linkage = LINKAGE_C;
5397                                 entity->declaration.type   = identify_new_type(new_type);
5398                         }
5399
5400                         if (enable_main_collect2_hack)
5401                                 prepare_main_collect2(entity);
5402                 }
5403
5404                 POP_CURRENT_ENTITY();
5405                 POP_PARENT();
5406                 assert(current_function == function);
5407                 current_function = old_current_function;
5408                 label_pop_to(label_stack_top);
5409         }
5410
5411         POP_SCOPE();
5412 }
5413
5414 static entity_t *find_compound_entry(compound_t *compound, symbol_t *symbol)
5415 {
5416         entity_t *iter = compound->members.entities;
5417         for (; iter != NULL; iter = iter->base.next) {
5418                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5419                         continue;
5420
5421                 if (iter->base.symbol == symbol) {
5422                         return iter;
5423                 } else if (iter->base.symbol == NULL) {
5424                         /* search in anonymous structs and unions */
5425                         type_t *type = skip_typeref(iter->declaration.type);
5426                         if (is_type_compound(type)) {
5427                                 if (find_compound_entry(type->compound.compound, symbol)
5428                                                 != NULL)
5429                                         return iter;
5430                         }
5431                         continue;
5432                 }
5433         }
5434
5435         return NULL;
5436 }
5437
5438 static void check_deprecated(const source_position_t *source_position,
5439                              const entity_t *entity)
5440 {
5441         if (!is_declaration(entity))
5442                 return;
5443         if ((entity->declaration.modifiers & DM_DEPRECATED) == 0)
5444                 return;
5445
5446         source_position_t const *const epos = &entity->base.source_position;
5447         char              const *const msg  = get_deprecated_string(entity->declaration.attributes);
5448         if (msg != NULL) {
5449                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P): \"%s\"", entity, epos, msg);
5450         } else {
5451                 warningf(WARN_DEPRECATED_DECLARATIONS, source_position, "'%N' is deprecated (declared %P)", entity, epos);
5452         }
5453 }
5454
5455
5456 static expression_t *create_select(const source_position_t *pos,
5457                                    expression_t *addr,
5458                                    type_qualifiers_t qualifiers,
5459                                                                    entity_t *entry)
5460 {
5461         assert(entry->kind == ENTITY_COMPOUND_MEMBER);
5462
5463         check_deprecated(pos, entry);
5464
5465         expression_t *select          = allocate_expression_zero(EXPR_SELECT);
5466         select->select.compound       = addr;
5467         select->select.compound_entry = entry;
5468
5469         type_t *entry_type = entry->declaration.type;
5470         type_t *res_type   = get_qualified_type(entry_type, qualifiers);
5471
5472         /* bitfields need special treatment */
5473         if (entry->compound_member.bitfield) {
5474                 unsigned bit_size = entry->compound_member.bit_size;
5475                 /* if fewer bits than an int, convert to int (see §6.3.1.1) */
5476                 if (bit_size < get_atomic_type_size(ATOMIC_TYPE_INT) * BITS_PER_BYTE) {
5477                         res_type = type_int;
5478                 }
5479         }
5480
5481         /* we always do the auto-type conversions; the & and sizeof parser contains
5482          * code to revert this! */
5483         select->base.type = automatic_type_conversion(res_type);
5484
5485
5486         return select;
5487 }
5488
5489 /**
5490  * Find entry with symbol in compound. Search anonymous structs and unions and
5491  * creates implicit select expressions for them.
5492  * Returns the adress for the innermost compound.
5493  */
5494 static expression_t *find_create_select(const source_position_t *pos,
5495                                         expression_t *addr,
5496                                         type_qualifiers_t qualifiers,
5497                                         compound_t *compound, symbol_t *symbol)
5498 {
5499         entity_t *iter = compound->members.entities;
5500         for (; iter != NULL; iter = iter->base.next) {
5501                 if (iter->kind != ENTITY_COMPOUND_MEMBER)
5502                         continue;
5503
5504                 symbol_t *iter_symbol = iter->base.symbol;
5505                 if (iter_symbol == NULL) {
5506                         type_t *type = iter->declaration.type;
5507                         if (type->kind != TYPE_COMPOUND_STRUCT
5508                                         && type->kind != TYPE_COMPOUND_UNION)
5509                                 continue;
5510
5511                         compound_t *sub_compound = type->compound.compound;
5512
5513                         if (find_compound_entry(sub_compound, symbol) == NULL)
5514                                 continue;
5515
5516                         expression_t *sub_addr = create_select(pos, addr, qualifiers, iter);
5517                         sub_addr->base.source_position = *pos;
5518                         sub_addr->base.implicit        = true;
5519                         return find_create_select(pos, sub_addr, qualifiers, sub_compound,
5520                                                   symbol);
5521                 }
5522
5523                 if (iter_symbol == symbol) {
5524                         return create_select(pos, addr, qualifiers, iter);
5525                 }
5526         }
5527
5528         return NULL;
5529 }
5530
5531 static void parse_bitfield_member(entity_t *entity)
5532 {
5533         eat(':');
5534
5535         expression_t *size = parse_constant_expression();
5536         long          size_long;
5537
5538         assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5539         type_t *type = entity->declaration.type;
5540         if (!is_type_integer(skip_typeref(type))) {
5541                 errorf(HERE, "bitfield base type '%T' is not an integer type",
5542                            type);
5543         }
5544
5545         if (is_constant_expression(size) != EXPR_CLASS_CONSTANT) {
5546                 /* error already reported by parse_constant_expression */
5547                 size_long = get_type_size(type) * 8;
5548         } else {
5549                 size_long = fold_constant_to_int(size);
5550
5551                 const symbol_t *symbol = entity->base.symbol;
5552                 const symbol_t *user_symbol
5553                         = symbol == NULL ? sym_anonymous : symbol;
5554                 unsigned bit_size = get_type_size(type) * 8;
5555                 if (size_long < 0) {
5556                         errorf(HERE, "negative width in bit-field '%Y'", user_symbol);
5557                 } else if (size_long == 0 && symbol != NULL) {
5558                         errorf(HERE, "zero width for bit-field '%Y'", user_symbol);
5559                 } else if (bit_size > 0 && (unsigned)size_long > bit_size) {
5560                         errorf(HERE, "width of bitfield '%Y' exceeds its type",
5561                                    user_symbol);
5562                 } else {
5563                         /* hope that people don't invent crazy types with more bits
5564                          * than our struct can hold */
5565                         assert(size_long <
5566                                    (1 << sizeof(entity->compound_member.bit_size)*8));
5567                 }
5568         }
5569
5570         entity->compound_member.bitfield = true;
5571         entity->compound_member.bit_size = (unsigned char)size_long;
5572 }
5573
5574 static void parse_compound_declarators(compound_t *compound,
5575                 const declaration_specifiers_t *specifiers)
5576 {
5577         add_anchor_token(';');
5578         add_anchor_token(',');
5579         do {
5580                 entity_t *entity;
5581
5582                 if (token.kind == ':') {
5583                         /* anonymous bitfield */
5584                         type_t *type = specifiers->type;
5585                         entity_t *const entity = allocate_entity_zero(ENTITY_COMPOUND_MEMBER, NAMESPACE_NORMAL, NULL, HERE);
5586                         entity->declaration.declared_storage_class = STORAGE_CLASS_NONE;
5587                         entity->declaration.storage_class          = STORAGE_CLASS_NONE;
5588                         entity->declaration.type                   = type;
5589
5590                         parse_bitfield_member(entity);
5591
5592                         attribute_t  *attributes = parse_attributes(NULL);
5593                         attribute_t **anchor     = &attributes;
5594                         while (*anchor != NULL)
5595                                 anchor = &(*anchor)->next;
5596                         *anchor = specifiers->attributes;
5597                         if (attributes != NULL) {
5598                                 handle_entity_attributes(attributes, entity);
5599                         }
5600                         entity->declaration.attributes = attributes;
5601
5602                         append_entity(&compound->members, entity);
5603                 } else {
5604                         entity = parse_declarator(specifiers,
5605                                         DECL_MAY_BE_ABSTRACT | DECL_CREATE_COMPOUND_MEMBER);
5606                         source_position_t const *const pos = &entity->base.source_position;
5607                         if (entity->kind == ENTITY_TYPEDEF) {
5608                                 errorf(pos, "typedef not allowed as compound member");
5609                         } else {
5610                                 assert(entity->kind == ENTITY_COMPOUND_MEMBER);
5611
5612                                 /* make sure we don't define a symbol multiple times */
5613                                 symbol_t *symbol = entity->base.symbol;
5614                                 if (symbol != NULL) {
5615                                         entity_t *prev = find_compound_entry(compound, symbol);
5616                                         if (prev != NULL) {
5617                                                 source_position_t const *const ppos = &prev->base.source_position;
5618                                                 errorf(pos, "multiple declarations of '%N' (declared %P)", entity, ppos);
5619                                         }
5620                                 }
5621
5622                                 if (token.kind == ':') {
5623                                         parse_bitfield_member(entity);
5624
5625                                         attribute_t *attributes = parse_attributes(NULL);
5626                                         handle_entity_attributes(attributes, entity);
5627                                 } else {
5628                                         type_t *orig_type = entity->declaration.type;
5629                                         type_t *type      = skip_typeref(orig_type);
5630                                         if (is_type_function(type)) {
5631                                                 errorf(pos, "'%N' must not have function type '%T'", entity, orig_type);
5632                                         } else if (is_type_incomplete(type)) {
5633                                                 /* §6.7.2.1:16 flexible array member */
5634                                                 if (!is_type_array(type)       ||
5635                                                                 token.kind          != ';' ||
5636                                                                 look_ahead(1)->kind != '}') {
5637                                                         errorf(pos, "'%N' has incomplete type '%T'", entity, orig_type);
5638                                                 } else if (compound->members.entities == NULL) {
5639                                                         errorf(pos, "flexible array member in otherwise empty struct");
5640                                                 }
5641                                         }
5642                                 }
5643
5644                                 append_entity(&compound->members, entity);
5645                         }
5646                 }
5647         } while (next_if(','));
5648         rem_anchor_token(',');
5649         rem_anchor_token(';');
5650         expect(';');
5651
5652         anonymous_entity = NULL;
5653 }
5654
5655 static void parse_compound_type_entries(compound_t *compound)
5656 {
5657         eat('{');
5658         add_anchor_token('}');
5659
5660         for (;;) {
5661                 switch (token.kind) {
5662                         DECLARATION_START
5663                         case T___extension__:
5664                         case T_IDENTIFIER: {
5665                                 PUSH_EXTENSION();
5666                                 declaration_specifiers_t specifiers;
5667                                 parse_declaration_specifiers(&specifiers);
5668                                 parse_compound_declarators(compound, &specifiers);
5669                                 POP_EXTENSION();
5670                                 break;
5671                         }
5672
5673                         default:
5674                                 rem_anchor_token('}');
5675                                 expect('}');
5676                                 /* §6.7.2.1:7 */
5677                                 compound->complete = true;
5678                                 return;
5679                 }
5680         }
5681 }
5682
5683 static type_t *parse_typename(void)
5684 {
5685         declaration_specifiers_t specifiers;
5686         parse_declaration_specifiers(&specifiers);
5687         if (specifiers.storage_class != STORAGE_CLASS_NONE
5688                         || specifiers.thread_local) {
5689                 /* TODO: improve error message, user does probably not know what a
5690                  * storage class is...
5691                  */
5692                 errorf(&specifiers.source_position, "typename must not have a storage class");
5693         }
5694
5695         type_t *result = parse_abstract_declarator(specifiers.type);
5696
5697         return result;
5698 }
5699
5700
5701
5702
5703 typedef expression_t* (*parse_expression_function)(void);
5704 typedef expression_t* (*parse_expression_infix_function)(expression_t *left);
5705
5706 typedef struct expression_parser_function_t expression_parser_function_t;
5707 struct expression_parser_function_t {
5708         parse_expression_function        parser;
5709         precedence_t                     infix_precedence;
5710         parse_expression_infix_function  infix_parser;
5711 };
5712
5713 static expression_parser_function_t expression_parsers[T_LAST_TOKEN];
5714
5715 static type_t *get_string_type(string_encoding_t const enc)
5716 {
5717         bool const warn = is_warn_on(WARN_WRITE_STRINGS);
5718         switch (enc) {
5719         case STRING_ENCODING_CHAR: return warn ? type_const_char_ptr    : type_char_ptr;
5720         case STRING_ENCODING_WIDE: return warn ? type_const_wchar_t_ptr : type_wchar_t_ptr;
5721         }
5722         panic("invalid string encoding");
5723 }
5724
5725 /**
5726  * Parse a string constant.
5727  */
5728 static expression_t *parse_string_literal(void)
5729 {
5730         expression_t *const expr = allocate_expression_zero(EXPR_STRING_LITERAL);
5731         expr->string_literal.value = concat_string_literals(&expr->string_literal.encoding);
5732         expr->base.type            = get_string_type(expr->string_literal.encoding);
5733         return expr;
5734 }
5735
5736 /**
5737  * Parse a boolean constant.
5738  */
5739 static expression_t *parse_boolean_literal(bool value)
5740 {
5741         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_BOOLEAN);
5742         literal->base.type           = type_bool;
5743         literal->literal.value.begin = value ? "true" : "false";
5744         literal->literal.value.size  = value ? 4 : 5;
5745
5746         eat(value ? T_true : T_false);
5747         return literal;
5748 }
5749
5750 static void warn_traditional_suffix(void)
5751 {
5752         warningf(WARN_TRADITIONAL, HERE, "traditional C rejects the '%S' suffix",
5753                  &token.number.suffix);
5754 }
5755
5756 static void check_integer_suffix(void)
5757 {
5758         const string_t *suffix = &token.number.suffix;
5759         if (suffix->size == 0)
5760                 return;
5761
5762         bool not_traditional = false;
5763         const char *c = suffix->begin;
5764         if (*c == 'l' || *c == 'L') {
5765                 ++c;
5766                 if (*c == *(c-1)) {
5767                         not_traditional = true;
5768                         ++c;
5769                         if (*c == 'u' || *c == 'U') {
5770                                 ++c;
5771                         }
5772                 } else if (*c == 'u' || *c == 'U') {
5773                         not_traditional = true;
5774                         ++c;
5775                 }
5776         } else if (*c == 'u' || *c == 'U') {
5777                 not_traditional = true;
5778                 ++c;
5779                 if (*c == 'l' || *c == 'L') {
5780                         ++c;
5781                         if (*c == *(c-1)) {
5782                                 ++c;
5783                         }
5784                 }
5785         }
5786         if (*c != '\0') {
5787                 errorf(HERE, "invalid suffix '%S' on integer constant", suffix);
5788         } else if (not_traditional) {
5789                 warn_traditional_suffix();
5790         }
5791 }
5792
5793 static type_t *check_floatingpoint_suffix(void)
5794 {
5795         const string_t *suffix = &token.number.suffix;
5796         type_t         *type   = type_double;
5797         if (suffix->size == 0)
5798                 return type;
5799
5800         bool not_traditional = false;
5801         const char *c = suffix->begin;
5802         if (*c == 'f' || *c == 'F') {
5803                 ++c;
5804                 type = type_float;
5805         } else if (*c == 'l' || *c == 'L') {
5806                 ++c;
5807                 type = type_long_double;
5808         }
5809         if (*c != '\0') {
5810                 errorf(HERE, "invalid suffix '%S' on floatingpoint constant", suffix);
5811         } else if (not_traditional) {
5812                 warn_traditional_suffix();
5813         }
5814
5815         return type;
5816 }
5817
5818 /**
5819  * Parse an integer constant.
5820  */
5821 static expression_t *parse_number_literal(void)
5822 {
5823         expression_kind_t  kind;
5824         type_t            *type;
5825
5826         switch (token.kind) {
5827         case T_INTEGER:
5828                 kind = EXPR_LITERAL_INTEGER;
5829                 check_integer_suffix();
5830                 type = type_int;
5831                 break;
5832
5833         case T_FLOATINGPOINT:
5834                 kind = EXPR_LITERAL_FLOATINGPOINT;
5835                 type = check_floatingpoint_suffix();
5836                 break;
5837
5838         default:
5839                 panic("unexpected token type in parse_number_literal");
5840         }
5841
5842         expression_t *literal = allocate_expression_zero(kind);
5843         literal->base.type      = type;
5844         literal->literal.value  = token.number.number;
5845         literal->literal.suffix = token.number.suffix;
5846         next_token();
5847
5848         /* integer type depends on the size of the number and the size
5849          * representable by the types. The backend/codegeneration has to determine
5850          * that
5851          */
5852         determine_literal_type(&literal->literal);
5853         return literal;
5854 }
5855
5856 /**
5857  * Parse a character constant.
5858  */
5859 static expression_t *parse_character_constant(void)
5860 {
5861         expression_t *literal;
5862         switch (token.string.encoding) {
5863         case STRING_ENCODING_CHAR: {
5864                 literal = allocate_expression_zero(EXPR_LITERAL_CHARACTER);
5865                 literal->base.type            = c_mode & _CXX ? type_char : type_int;
5866                 literal->string_literal.value = token.string.string;
5867
5868                 if (literal->string_literal.value.size > 1) {
5869                         if (!GNU_MODE && !(c_mode & _C99)) {
5870                                 errorf(HERE, "more than 1 character in character constant");
5871                         } else {
5872                                 literal->base.type = type_int;
5873                                 warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5874                         }
5875                 }
5876                 break;
5877         }
5878
5879         case STRING_ENCODING_WIDE: {
5880                 literal = allocate_expression_zero(EXPR_LITERAL_WIDE_CHARACTER);
5881                 literal->base.type            = type_int;
5882                 literal->string_literal.value = token.string.string;
5883
5884                 if (wstrlen(&literal->string_literal.value) > 1) {
5885                         warningf(WARN_MULTICHAR, HERE, "multi-character character constant");
5886                 }
5887                 break;
5888         }
5889         }
5890
5891         eat(T_CHARACTER_CONSTANT);
5892         return literal;
5893 }
5894
5895 static entity_t *create_implicit_function(symbol_t *symbol, source_position_t const *const pos)
5896 {
5897         type_t *ntype                          = allocate_type_zero(TYPE_FUNCTION);
5898         ntype->function.return_type            = type_int;
5899         ntype->function.unspecified_parameters = true;
5900         ntype->function.linkage                = LINKAGE_C;
5901         type_t *type                           = identify_new_type(ntype);
5902
5903         entity_t *const entity = allocate_entity_zero(ENTITY_FUNCTION, NAMESPACE_NORMAL, symbol, pos);
5904         entity->declaration.storage_class          = STORAGE_CLASS_EXTERN;
5905         entity->declaration.declared_storage_class = STORAGE_CLASS_EXTERN;
5906         entity->declaration.type                   = type;
5907         entity->declaration.implicit               = true;
5908
5909         if (current_scope != NULL)
5910                 record_entity(entity, false);
5911
5912         return entity;
5913 }
5914
5915 /**
5916  * Performs automatic type cast as described in §6.3.2.1.
5917  *
5918  * @param orig_type  the original type
5919  */
5920 static type_t *automatic_type_conversion(type_t *orig_type)
5921 {
5922         type_t *type = skip_typeref(orig_type);
5923         if (is_type_array(type)) {
5924                 array_type_t *array_type   = &type->array;
5925                 type_t       *element_type = array_type->element_type;
5926                 unsigned      qualifiers   = array_type->base.qualifiers;
5927
5928                 return make_pointer_type(element_type, qualifiers);
5929         }
5930
5931         if (is_type_function(type)) {
5932                 return make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
5933         }
5934
5935         return orig_type;
5936 }
5937
5938 /**
5939  * reverts the automatic casts of array to pointer types and function
5940  * to function-pointer types as defined §6.3.2.1
5941  */
5942 type_t *revert_automatic_type_conversion(const expression_t *expression)
5943 {
5944         switch (expression->kind) {
5945         case EXPR_REFERENCE: {
5946                 entity_t *entity = expression->reference.entity;
5947                 if (is_declaration(entity)) {
5948                         return entity->declaration.type;
5949                 } else if (entity->kind == ENTITY_ENUM_VALUE) {
5950                         return entity->enum_value.enum_type;
5951                 } else {
5952                         panic("no declaration or enum in reference");
5953                 }
5954         }
5955
5956         case EXPR_SELECT: {
5957                 entity_t *entity = expression->select.compound_entry;
5958                 assert(is_declaration(entity));
5959                 type_t   *type   = entity->declaration.type;
5960                 return get_qualified_type(type, expression->base.type->base.qualifiers);
5961         }
5962
5963         case EXPR_UNARY_DEREFERENCE: {
5964                 const expression_t *const value = expression->unary.value;
5965                 type_t             *const type  = skip_typeref(value->base.type);
5966                 if (!is_type_pointer(type))
5967                         return type_error_type;
5968                 return type->pointer.points_to;
5969         }
5970
5971         case EXPR_ARRAY_ACCESS: {
5972                 const expression_t *array_ref = expression->array_access.array_ref;
5973                 type_t             *type_left = skip_typeref(array_ref->base.type);
5974                 if (!is_type_pointer(type_left))
5975                         return type_error_type;
5976                 return type_left->pointer.points_to;
5977         }
5978
5979         case EXPR_STRING_LITERAL: {
5980                 size_t  const size = expression->string_literal.value.size + 1;
5981                 type_t *const elem = get_unqualified_type(expression->base.type->pointer.points_to);
5982                 return make_array_type(elem, size, TYPE_QUALIFIER_NONE);
5983         }
5984
5985         case EXPR_COMPOUND_LITERAL:
5986                 return expression->compound_literal.type;
5987
5988         default:
5989                 break;
5990         }
5991         return expression->base.type;
5992 }
5993
5994 /**
5995  * Find an entity matching a symbol in a scope.
5996  * Uses current scope if scope is NULL
5997  */
5998 static entity_t *lookup_entity(const scope_t *scope, symbol_t *symbol,
5999                                namespace_tag_t namespc)
6000 {
6001         if (scope == NULL) {
6002                 return get_entity(symbol, namespc);
6003         }
6004
6005         /* we should optimize here, if scope grows above a certain size we should
6006            construct a hashmap here... */
6007         entity_t *entity = scope->entities;
6008         for ( ; entity != NULL; entity = entity->base.next) {
6009                 if (entity->base.symbol == symbol
6010                     && (namespace_tag_t)entity->base.namespc == namespc)
6011                         break;
6012         }
6013
6014         return entity;
6015 }
6016
6017 static entity_t *parse_qualified_identifier(void)
6018 {
6019         /* namespace containing the symbol */
6020         symbol_t          *symbol;
6021         source_position_t  pos;
6022         const scope_t     *lookup_scope = NULL;
6023
6024         if (next_if(T_COLONCOLON))
6025                 lookup_scope = &unit->scope;
6026
6027         entity_t *entity;
6028         while (true) {
6029                 symbol = expect_identifier("while parsing identifier", &pos);
6030                 if (!symbol)
6031                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6032
6033                 /* lookup entity */
6034                 entity = lookup_entity(lookup_scope, symbol, NAMESPACE_NORMAL);
6035
6036                 if (!next_if(T_COLONCOLON))
6037                         break;
6038
6039                 switch (entity->kind) {
6040                 case ENTITY_NAMESPACE:
6041                         lookup_scope = &entity->namespacee.members;
6042                         break;
6043                 case ENTITY_STRUCT:
6044                 case ENTITY_UNION:
6045                 case ENTITY_CLASS:
6046                         lookup_scope = &entity->compound.members;
6047                         break;
6048                 default:
6049                         errorf(&pos, "'%Y' must be a namespace, class, struct or union (but is a %s)",
6050                                symbol, get_entity_kind_name(entity->kind));
6051
6052                         /* skip further qualifications */
6053                         while (next_if(T_IDENTIFIER) && next_if(T_COLONCOLON)) {}
6054
6055                         return create_error_entity(sym_anonymous, ENTITY_VARIABLE);
6056                 }
6057         }
6058
6059         if (entity == NULL) {
6060                 if (!strict_mode && token.kind == '(') {
6061                         /* an implicitly declared function */
6062                         entity = create_implicit_function(symbol, &pos);
6063                         warningf(WARN_IMPLICIT_FUNCTION_DECLARATION, &pos, "implicit declaration of '%N'", entity);
6064                 } else {
6065                         errorf(&pos, "unknown identifier '%Y' found.", symbol);
6066                         entity = create_error_entity(symbol, ENTITY_VARIABLE);
6067                 }
6068         }
6069
6070         return entity;
6071 }
6072
6073 static expression_t *parse_reference(void)
6074 {
6075         source_position_t const pos    = *HERE;
6076         entity_t         *const entity = parse_qualified_identifier();
6077
6078         type_t *orig_type;
6079         if (is_declaration(entity)) {
6080                 orig_type = entity->declaration.type;
6081         } else if (entity->kind == ENTITY_ENUM_VALUE) {
6082                 orig_type = entity->enum_value.enum_type;
6083         } else {
6084                 panic("expected declaration or enum value in reference");
6085         }
6086
6087         /* we always do the auto-type conversions; the & and sizeof parser contains
6088          * code to revert this! */
6089         type_t *type = automatic_type_conversion(orig_type);
6090
6091         expression_kind_t kind = EXPR_REFERENCE;
6092         if (entity->kind == ENTITY_ENUM_VALUE)
6093                 kind = EXPR_ENUM_CONSTANT;
6094
6095         expression_t *expression         = allocate_expression_zero(kind);
6096         expression->base.source_position = pos;
6097         expression->base.type            = type;
6098         expression->reference.entity     = entity;
6099
6100         /* this declaration is used */
6101         if (is_declaration(entity)) {
6102                 entity->declaration.used = true;
6103         }
6104
6105         if (entity->base.parent_scope != file_scope
6106                 && (current_function != NULL
6107                         && entity->base.parent_scope->depth < current_function->parameters.depth)
6108                 && (entity->kind == ENTITY_VARIABLE || entity->kind == ENTITY_PARAMETER)) {
6109                 /* access of a variable from an outer function */
6110                 entity->variable.address_taken = true;
6111                 current_function->need_closure = true;
6112         }
6113
6114         check_deprecated(&pos, entity);
6115
6116         return expression;
6117 }
6118
6119 static bool semantic_cast(expression_t *cast)
6120 {
6121         expression_t            *expression      = cast->unary.value;
6122         type_t                  *orig_dest_type  = cast->base.type;
6123         type_t                  *orig_type_right = expression->base.type;
6124         type_t            const *dst_type        = skip_typeref(orig_dest_type);
6125         type_t            const *src_type        = skip_typeref(orig_type_right);
6126         source_position_t const *pos             = &cast->base.source_position;
6127
6128         /* §6.5.4 A (void) cast is explicitly permitted, more for documentation than for utility. */
6129         if (is_type_void(dst_type))
6130                 return true;
6131
6132         /* only integer and pointer can be casted to pointer */
6133         if (is_type_pointer(dst_type)  &&
6134             !is_type_pointer(src_type) &&
6135             !is_type_integer(src_type) &&
6136             is_type_valid(src_type)) {
6137                 errorf(pos, "cannot convert type '%T' to a pointer type", orig_type_right);
6138                 return false;
6139         }
6140
6141         if (!is_type_scalar(dst_type) && is_type_valid(dst_type)) {
6142                 errorf(pos, "conversion to non-scalar type '%T' requested", orig_dest_type);
6143                 return false;
6144         }
6145
6146         if (!is_type_scalar(src_type) && is_type_valid(src_type)) {
6147                 errorf(pos, "conversion from non-scalar type '%T' requested", orig_type_right);
6148                 return false;
6149         }
6150
6151         if (is_type_pointer(src_type) && is_type_pointer(dst_type)) {
6152                 type_t *src = skip_typeref(src_type->pointer.points_to);
6153                 type_t *dst = skip_typeref(dst_type->pointer.points_to);
6154                 unsigned missing_qualifiers =
6155                         src->base.qualifiers & ~dst->base.qualifiers;
6156                 if (missing_qualifiers != 0) {
6157                         warningf(WARN_CAST_QUAL, pos, "cast discards qualifiers '%Q' in pointer target type of '%T'", missing_qualifiers, orig_type_right);
6158                 }
6159         }
6160         return true;
6161 }
6162
6163 static expression_t *parse_compound_literal(source_position_t const *const pos, type_t *type)
6164 {
6165         expression_t *expression = allocate_expression_zero(EXPR_COMPOUND_LITERAL);
6166         expression->base.source_position = *pos;
6167
6168         parse_initializer_env_t env;
6169         env.type             = type;
6170         env.entity           = NULL;
6171         env.must_be_constant = false;
6172         initializer_t *initializer = parse_initializer(&env);
6173         type = env.type;
6174
6175         expression->compound_literal.initializer = initializer;
6176         expression->compound_literal.type        = type;
6177         expression->base.type                    = automatic_type_conversion(type);
6178
6179         return expression;
6180 }
6181
6182 /**
6183  * Parse a cast expression.
6184  */
6185 static expression_t *parse_cast(void)
6186 {
6187         source_position_t const pos = *HERE;
6188
6189         eat('(');
6190         add_anchor_token(')');
6191
6192         type_t *type = parse_typename();
6193
6194         rem_anchor_token(')');
6195         expect(')');
6196
6197         if (token.kind == '{') {
6198                 return parse_compound_literal(&pos, type);
6199         }
6200
6201         expression_t *cast = allocate_expression_zero(EXPR_UNARY_CAST);
6202         cast->base.source_position = pos;
6203
6204         expression_t *value = parse_subexpression(PREC_CAST);
6205         cast->base.type   = type;
6206         cast->unary.value = value;
6207
6208         if (! semantic_cast(cast)) {
6209                 /* TODO: record the error in the AST. else it is impossible to detect it */
6210         }
6211
6212         return cast;
6213 }
6214
6215 /**
6216  * Parse a statement expression.
6217  */
6218 static expression_t *parse_statement_expression(void)
6219 {
6220         expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
6221
6222         eat('(');
6223         add_anchor_token(')');
6224
6225         statement_t *statement          = parse_compound_statement(true);
6226         statement->compound.stmt_expr   = true;
6227         expression->statement.statement = statement;
6228
6229         /* find last statement and use its type */
6230         type_t *type = type_void;
6231         const statement_t *stmt = statement->compound.statements;
6232         if (stmt != NULL) {
6233                 while (stmt->base.next != NULL)
6234                         stmt = stmt->base.next;
6235
6236                 if (stmt->kind == STATEMENT_EXPRESSION) {
6237                         type = stmt->expression.expression->base.type;
6238                 }
6239         } else {
6240                 source_position_t const *const pos = &expression->base.source_position;
6241                 warningf(WARN_OTHER, pos, "empty statement expression ({})");
6242         }
6243         expression->base.type = type;
6244
6245         rem_anchor_token(')');
6246         expect(')');
6247         return expression;
6248 }
6249
6250 /**
6251  * Parse a parenthesized expression.
6252  */
6253 static expression_t *parse_parenthesized_expression(void)
6254 {
6255         token_t const* const la1 = look_ahead(1);
6256         switch (la1->kind) {
6257         case '{':
6258                 /* gcc extension: a statement expression */
6259                 return parse_statement_expression();
6260
6261         case T_IDENTIFIER:
6262                 if (is_typedef_symbol(la1->base.symbol)) {
6263         DECLARATION_START
6264                         return parse_cast();
6265                 }
6266         }
6267
6268         eat('(');
6269         add_anchor_token(')');
6270         expression_t *result = parse_expression();
6271         result->base.parenthesized = true;
6272         rem_anchor_token(')');
6273         expect(')');
6274
6275         return result;
6276 }
6277
6278 static expression_t *parse_function_keyword(funcname_kind_t const kind)
6279 {
6280         if (current_function == NULL) {
6281                 errorf(HERE, "'%K' used outside of a function", &token);
6282         }
6283
6284         expression_t *expression  = allocate_expression_zero(EXPR_FUNCNAME);
6285         expression->base.type     = type_char_ptr;
6286         expression->funcname.kind = kind;
6287
6288         next_token();
6289
6290         return expression;
6291 }
6292
6293 static designator_t *parse_designator(void)
6294 {
6295         designator_t *const result = allocate_ast_zero(sizeof(result[0]));
6296         result->symbol = expect_identifier("while parsing member designator", &result->source_position);
6297         if (!result->symbol)
6298                 return NULL;
6299
6300         designator_t *last_designator = result;
6301         while (true) {
6302                 if (next_if('.')) {
6303                         designator_t *const designator = allocate_ast_zero(sizeof(result[0]));
6304                         designator->symbol = expect_identifier("while parsing member designator", &designator->source_position);
6305                         if (!designator->symbol)
6306                                 return NULL;
6307
6308                         last_designator->next = designator;
6309                         last_designator       = designator;
6310                         continue;
6311                 }
6312                 if (next_if('[')) {
6313                         add_anchor_token(']');
6314                         designator_t *designator    = allocate_ast_zero(sizeof(result[0]));
6315                         designator->source_position = *HERE;
6316                         designator->array_index     = parse_expression();
6317                         rem_anchor_token(']');
6318                         expect(']');
6319                         if (designator->array_index == NULL) {
6320                                 return NULL;
6321                         }
6322
6323                         last_designator->next = designator;
6324                         last_designator       = designator;
6325                         continue;
6326                 }
6327                 break;
6328         }
6329
6330         return result;
6331 }
6332
6333 /**
6334  * Parse the __builtin_offsetof() expression.
6335  */
6336 static expression_t *parse_offsetof(void)
6337 {
6338         expression_t *expression = allocate_expression_zero(EXPR_OFFSETOF);
6339         expression->base.type    = type_size_t;
6340
6341         eat(T___builtin_offsetof);
6342
6343         add_anchor_token(')');
6344         add_anchor_token(',');
6345         expect('(');
6346         type_t *type = parse_typename();
6347         rem_anchor_token(',');
6348         expect(',');
6349         designator_t *designator = parse_designator();
6350         rem_anchor_token(')');
6351         expect(')');
6352
6353         expression->offsetofe.type       = type;
6354         expression->offsetofe.designator = designator;
6355
6356         type_path_t path;
6357         memset(&path, 0, sizeof(path));
6358         path.top_type = type;
6359         path.path     = NEW_ARR_F(type_path_entry_t, 0);
6360
6361         descend_into_subtype(&path);
6362
6363         if (!walk_designator(&path, designator, true)) {
6364                 return create_error_expression();
6365         }
6366
6367         DEL_ARR_F(path.path);
6368
6369         return expression;
6370 }
6371
6372 static bool is_last_parameter(expression_t *const param)
6373 {
6374         if (param->kind == EXPR_REFERENCE) {
6375                 entity_t *const entity = param->reference.entity;
6376                 if (entity->kind == ENTITY_PARAMETER &&
6377                     !entity->base.next               &&
6378                     entity->base.parent_scope == &current_function->parameters) {
6379                         return true;
6380                 }
6381         }
6382
6383         if (!is_type_valid(skip_typeref(param->base.type)))
6384                 return true;
6385
6386         return false;
6387 }
6388
6389 /**
6390  * Parses a __builtin_va_start() expression.
6391  */
6392 static expression_t *parse_va_start(void)
6393 {
6394         expression_t *expression = allocate_expression_zero(EXPR_VA_START);
6395
6396         eat(T___builtin_va_start);
6397
6398         add_anchor_token(')');
6399         add_anchor_token(',');
6400         expect('(');
6401         expression->va_starte.ap = parse_assignment_expression();
6402         rem_anchor_token(',');
6403         expect(',');
6404         expression_t *const param = parse_assignment_expression();
6405         expression->va_starte.parameter = param;
6406         rem_anchor_token(')');
6407         expect(')');
6408
6409         if (!current_function) {
6410                 errorf(&expression->base.source_position, "'va_start' used outside of function");
6411         } else if (!current_function->base.type->function.variadic) {
6412                 errorf(&expression->base.source_position, "'va_start' used in non-variadic function");
6413         } else if (!is_last_parameter(param)) {
6414                 errorf(&param->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
6415         }
6416
6417         return expression;
6418 }
6419
6420 /**
6421  * Parses a __builtin_va_arg() expression.
6422  */
6423 static expression_t *parse_va_arg(void)
6424 {
6425         expression_t *expression = allocate_expression_zero(EXPR_VA_ARG);
6426
6427         eat(T___builtin_va_arg);
6428
6429         add_anchor_token(')');
6430         add_anchor_token(',');
6431         expect('(');
6432         call_argument_t ap;
6433         ap.expression = parse_assignment_expression();
6434         expression->va_arge.ap = ap.expression;
6435         check_call_argument(type_valist, &ap, 1);
6436
6437         rem_anchor_token(',');
6438         expect(',');
6439         expression->base.type = parse_typename();
6440         rem_anchor_token(')');
6441         expect(')');
6442
6443         return expression;
6444 }
6445
6446 /**
6447  * Parses a __builtin_va_copy() expression.
6448  */
6449 static expression_t *parse_va_copy(void)
6450 {
6451         expression_t *expression = allocate_expression_zero(EXPR_VA_COPY);
6452
6453         eat(T___builtin_va_copy);
6454
6455         add_anchor_token(')');
6456         add_anchor_token(',');
6457         expect('(');
6458         expression_t *dst = parse_assignment_expression();
6459         assign_error_t error = semantic_assign(type_valist, dst);
6460         report_assign_error(error, type_valist, dst, "call argument 1",
6461                             &dst->base.source_position);
6462         expression->va_copye.dst = dst;
6463
6464         rem_anchor_token(',');
6465         expect(',');
6466
6467         call_argument_t src;
6468         src.expression = parse_assignment_expression();
6469         check_call_argument(type_valist, &src, 2);
6470         expression->va_copye.src = src.expression;
6471         rem_anchor_token(')');
6472         expect(')');
6473
6474         return expression;
6475 }
6476
6477 /**
6478  * Parses a __builtin_constant_p() expression.
6479  */
6480 static expression_t *parse_builtin_constant(void)
6481 {
6482         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
6483
6484         eat(T___builtin_constant_p);
6485
6486         add_anchor_token(')');
6487         expect('(');
6488         expression->builtin_constant.value = parse_assignment_expression();
6489         rem_anchor_token(')');
6490         expect(')');
6491         expression->base.type = type_int;
6492
6493         return expression;
6494 }
6495
6496 /**
6497  * Parses a __builtin_types_compatible_p() expression.
6498  */
6499 static expression_t *parse_builtin_types_compatible(void)
6500 {
6501         expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_TYPES_COMPATIBLE_P);
6502
6503         eat(T___builtin_types_compatible_p);
6504
6505         add_anchor_token(')');
6506         add_anchor_token(',');
6507         expect('(');
6508         expression->builtin_types_compatible.left = parse_typename();
6509         rem_anchor_token(',');
6510         expect(',');
6511         expression->builtin_types_compatible.right = parse_typename();
6512         rem_anchor_token(')');
6513         expect(')');
6514         expression->base.type = type_int;
6515
6516         return expression;
6517 }
6518
6519 /**
6520  * Parses a __builtin_is_*() compare expression.
6521  */
6522 static expression_t *parse_compare_builtin(void)
6523 {
6524         expression_kind_t kind;
6525         switch (token.kind) {
6526         case T___builtin_isgreater:      kind = EXPR_BINARY_ISGREATER;      break;
6527         case T___builtin_isgreaterequal: kind = EXPR_BINARY_ISGREATEREQUAL; break;
6528         case T___builtin_isless:         kind = EXPR_BINARY_ISLESS;         break;
6529         case T___builtin_islessequal:    kind = EXPR_BINARY_ISLESSEQUAL;    break;
6530         case T___builtin_islessgreater:  kind = EXPR_BINARY_ISLESSGREATER;  break;
6531         case T___builtin_isunordered:    kind = EXPR_BINARY_ISUNORDERED;    break;
6532         default: internal_errorf(HERE, "invalid compare builtin found");
6533         }
6534         expression_t *const expression = allocate_expression_zero(kind);
6535         next_token();
6536
6537         add_anchor_token(')');
6538         add_anchor_token(',');
6539         expect('(');
6540         expression->binary.left = parse_assignment_expression();
6541         rem_anchor_token(',');
6542         expect(',');
6543         expression->binary.right = parse_assignment_expression();
6544         rem_anchor_token(')');
6545         expect(')');
6546
6547         type_t *const orig_type_left  = expression->binary.left->base.type;
6548         type_t *const orig_type_right = expression->binary.right->base.type;
6549
6550         type_t *const type_left  = skip_typeref(orig_type_left);
6551         type_t *const type_right = skip_typeref(orig_type_right);
6552         if (!is_type_float(type_left) && !is_type_float(type_right)) {
6553                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
6554                         type_error_incompatible("invalid operands in comparison",
6555                                 &expression->base.source_position, orig_type_left, orig_type_right);
6556                 }
6557         } else {
6558                 semantic_comparison(&expression->binary);
6559         }
6560
6561         return expression;
6562 }
6563
6564 /**
6565  * Parses a MS assume() expression.
6566  */
6567 static expression_t *parse_assume(void)
6568 {
6569         expression_t *expression = allocate_expression_zero(EXPR_UNARY_ASSUME);
6570
6571         eat(T__assume);
6572
6573         add_anchor_token(')');
6574         expect('(');
6575         expression->unary.value = parse_assignment_expression();
6576         rem_anchor_token(')');
6577         expect(')');
6578
6579         expression->base.type = type_void;
6580         return expression;
6581 }
6582
6583 /**
6584  * Return the label for the current symbol or create a new one.
6585  */
6586 static label_t *get_label(char const *const context)
6587 {
6588         assert(current_function != NULL);
6589
6590         symbol_t *const sym = expect_identifier(context, NULL);
6591         if (!sym)
6592                 return NULL;
6593
6594         entity_t *label = get_entity(sym, NAMESPACE_LABEL);
6595         /* If we find a local label, we already created the declaration. */
6596         if (label != NULL && label->kind == ENTITY_LOCAL_LABEL) {
6597                 if (label->base.parent_scope != current_scope) {
6598                         assert(label->base.parent_scope->depth < current_scope->depth);
6599                         current_function->goto_to_outer = true;
6600                 }
6601         } else if (label == NULL || label->base.parent_scope != &current_function->parameters) {
6602                 /* There is no matching label in the same function, so create a new one. */
6603                 source_position_t const nowhere = { NULL, 0, 0, false };
6604                 label = allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym, &nowhere);
6605                 label_push(label);
6606         }
6607
6608         return &label->label;
6609 }
6610
6611 /**
6612  * Parses a GNU && label address expression.
6613  */
6614 static expression_t *parse_label_address(void)
6615 {
6616         source_position_t const source_position = *HERE;
6617         eat(T_ANDAND);
6618
6619         label_t *const label = get_label("while parsing label address");
6620         if (!label)
6621                 return create_error_expression();
6622
6623         label->used          = true;
6624         label->address_taken = true;
6625
6626         expression_t *expression = allocate_expression_zero(EXPR_LABEL_ADDRESS);
6627         expression->base.source_position = source_position;
6628
6629         /* label address is treated as a void pointer */
6630         expression->base.type           = type_void_ptr;
6631         expression->label_address.label = label;
6632         return expression;
6633 }
6634
6635 /**
6636  * Parse a microsoft __noop expression.
6637  */
6638 static expression_t *parse_noop_expression(void)
6639 {
6640         /* the result is a (int)0 */
6641         expression_t *literal = allocate_expression_zero(EXPR_LITERAL_MS_NOOP);
6642         literal->base.type           = type_int;
6643         literal->literal.value.begin = "__noop";
6644         literal->literal.value.size  = 6;
6645
6646         eat(T___noop);
6647
6648         if (token.kind == '(') {
6649                 /* parse arguments */
6650                 eat('(');
6651                 add_anchor_token(')');
6652                 add_anchor_token(',');
6653
6654                 if (token.kind != ')') do {
6655                         (void)parse_assignment_expression();
6656                 } while (next_if(','));
6657
6658                 rem_anchor_token(',');
6659                 rem_anchor_token(')');
6660         }
6661         expect(')');
6662
6663         return literal;
6664 }
6665
6666 /**
6667  * Parses a primary expression.
6668  */
6669 static expression_t *parse_primary_expression(void)
6670 {
6671         switch (token.kind) {
6672         case T_false:                        return parse_boolean_literal(false);
6673         case T_true:                         return parse_boolean_literal(true);
6674         case T_INTEGER:
6675         case T_FLOATINGPOINT:                return parse_number_literal();
6676         case T_CHARACTER_CONSTANT:           return parse_character_constant();
6677         case T_STRING_LITERAL:               return parse_string_literal();
6678         case T___func__:                     return parse_function_keyword(FUNCNAME_FUNCTION);
6679         case T___PRETTY_FUNCTION__:          return parse_function_keyword(FUNCNAME_PRETTY_FUNCTION);
6680         case T___FUNCSIG__:                  return parse_function_keyword(FUNCNAME_FUNCSIG);
6681         case T___FUNCDNAME__:                return parse_function_keyword(FUNCNAME_FUNCDNAME);
6682         case T___builtin_offsetof:           return parse_offsetof();
6683         case T___builtin_va_start:           return parse_va_start();
6684         case T___builtin_va_arg:             return parse_va_arg();
6685         case T___builtin_va_copy:            return parse_va_copy();
6686         case T___builtin_isgreater:
6687         case T___builtin_isgreaterequal:
6688         case T___builtin_isless:
6689         case T___builtin_islessequal:
6690         case T___builtin_islessgreater:
6691         case T___builtin_isunordered:        return parse_compare_builtin();
6692         case T___builtin_constant_p:         return parse_builtin_constant();
6693         case T___builtin_types_compatible_p: return parse_builtin_types_compatible();
6694         case T__assume:                      return parse_assume();
6695         case T_ANDAND:
6696                 if (GNU_MODE)
6697                         return parse_label_address();
6698                 break;
6699
6700         case '(':                            return parse_parenthesized_expression();
6701         case T___noop:                       return parse_noop_expression();
6702
6703         /* Gracefully handle type names while parsing expressions. */
6704         case T_COLONCOLON:
6705                 return parse_reference();
6706         case T_IDENTIFIER:
6707                 if (!is_typedef_symbol(token.base.symbol)) {
6708                         return parse_reference();
6709                 }
6710                 /* FALLTHROUGH */
6711         DECLARATION_START {
6712                 source_position_t const  pos = *HERE;
6713                 declaration_specifiers_t specifiers;
6714                 parse_declaration_specifiers(&specifiers);
6715                 type_t const *const type = parse_abstract_declarator(specifiers.type);
6716                 errorf(&pos, "encountered type '%T' while parsing expression", type);
6717                 return create_error_expression();
6718         }
6719         }
6720
6721         errorf(HERE, "unexpected token %K, expected an expression", &token);
6722         eat_until_anchor();
6723         return create_error_expression();
6724 }
6725
6726 static expression_t *parse_array_expression(expression_t *left)
6727 {
6728         expression_t              *const expr = allocate_expression_zero(EXPR_ARRAY_ACCESS);
6729         array_access_expression_t *const arr  = &expr->array_access;
6730
6731         eat('[');
6732         add_anchor_token(']');
6733
6734         expression_t *const inside = parse_expression();
6735
6736         type_t *const orig_type_left   = left->base.type;
6737         type_t *const orig_type_inside = inside->base.type;
6738
6739         type_t *const type_left   = skip_typeref(orig_type_left);
6740         type_t *const type_inside = skip_typeref(orig_type_inside);
6741
6742         expression_t *ref;
6743         expression_t *idx;
6744         type_t       *idx_type;
6745         type_t       *res_type;
6746         if (is_type_pointer(type_left)) {
6747                 ref      = left;
6748                 idx      = inside;
6749                 idx_type = type_inside;
6750                 res_type = type_left->pointer.points_to;
6751                 goto check_idx;
6752         } else if (is_type_pointer(type_inside)) {
6753                 arr->flipped = true;
6754                 ref      = inside;
6755                 idx      = left;
6756                 idx_type = type_left;
6757                 res_type = type_inside->pointer.points_to;
6758 check_idx:
6759                 res_type = automatic_type_conversion(res_type);
6760                 if (!is_type_integer(idx_type)) {
6761                         errorf(&idx->base.source_position, "array subscript must have integer type");
6762                 } else if (is_type_atomic(idx_type, ATOMIC_TYPE_CHAR)) {
6763                         source_position_t const *const pos = &idx->base.source_position;
6764                         warningf(WARN_CHAR_SUBSCRIPTS, pos, "array subscript has char type");
6765                 }
6766         } else {
6767                 if (is_type_valid(type_left) && is_type_valid(type_inside)) {
6768                         errorf(&expr->base.source_position, "invalid types '%T[%T]' for array access", orig_type_left, orig_type_inside);
6769                 }
6770                 res_type = type_error_type;
6771                 ref      = left;
6772                 idx      = inside;
6773         }
6774
6775         arr->array_ref = ref;
6776         arr->index     = idx;
6777         arr->base.type = res_type;
6778
6779         rem_anchor_token(']');
6780         expect(']');
6781         return expr;
6782 }
6783
6784 static bool is_bitfield(const expression_t *expression)
6785 {
6786         return expression->kind == EXPR_SELECT
6787                 && expression->select.compound_entry->compound_member.bitfield;
6788 }
6789
6790 static expression_t *parse_typeprop(expression_kind_t const kind)
6791 {
6792         expression_t  *tp_expression = allocate_expression_zero(kind);
6793         tp_expression->base.type     = type_size_t;
6794
6795         eat(kind == EXPR_SIZEOF ? T_sizeof : T___alignof__);
6796
6797         type_t       *orig_type;
6798         expression_t *expression;
6799         if (token.kind == '(' && is_declaration_specifier(look_ahead(1))) {
6800                 source_position_t const pos = *HERE;
6801                 eat('(');
6802                 add_anchor_token(')');
6803                 orig_type = parse_typename();
6804                 rem_anchor_token(')');
6805                 expect(')');
6806
6807                 if (token.kind == '{') {
6808                         /* It was not sizeof(type) after all.  It is sizeof of an expression
6809                          * starting with a compound literal */
6810                         expression = parse_compound_literal(&pos, orig_type);
6811                         goto typeprop_expression;
6812                 }
6813         } else {
6814                 expression = parse_subexpression(PREC_UNARY);
6815
6816 typeprop_expression:
6817                 if (is_bitfield(expression)) {
6818                         char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6819                         errorf(&tp_expression->base.source_position,
6820                                    "operand of %s expression must not be a bitfield", what);
6821                 }
6822
6823                 tp_expression->typeprop.tp_expression = expression;
6824
6825                 orig_type = revert_automatic_type_conversion(expression);
6826                 expression->base.type = orig_type;
6827         }
6828
6829         tp_expression->typeprop.type   = orig_type;
6830         type_t const* const type       = skip_typeref(orig_type);
6831         char   const*       wrong_type = NULL;
6832         if (is_type_incomplete(type)) {
6833                 if (!is_type_void(type) || !GNU_MODE)
6834                         wrong_type = "incomplete";
6835         } else if (type->kind == TYPE_FUNCTION) {
6836                 if (GNU_MODE) {
6837                         /* function types are allowed (and return 1) */
6838                         source_position_t const *const pos  = &tp_expression->base.source_position;
6839                         char              const *const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6840                         warningf(WARN_OTHER, pos, "%s expression with function argument returns invalid result", what);
6841                 } else {
6842                         wrong_type = "function";
6843                 }
6844         }
6845
6846         if (wrong_type != NULL) {
6847                 char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
6848                 errorf(&tp_expression->base.source_position,
6849                                 "operand of %s expression must not be of %s type '%T'",
6850                                 what, wrong_type, orig_type);
6851         }
6852
6853         return tp_expression;
6854 }
6855
6856 static expression_t *parse_sizeof(void)
6857 {
6858         return parse_typeprop(EXPR_SIZEOF);
6859 }
6860
6861 static expression_t *parse_alignof(void)
6862 {
6863         return parse_typeprop(EXPR_ALIGNOF);
6864 }
6865
6866 static expression_t *parse_select_expression(expression_t *addr)
6867 {
6868         assert(token.kind == '.' || token.kind == T_MINUSGREATER);
6869         bool select_left_arrow = (token.kind == T_MINUSGREATER);
6870         source_position_t const pos = *HERE;
6871         next_token();
6872
6873         symbol_t *const symbol = expect_identifier("while parsing select", NULL);
6874         if (!symbol)
6875                 return create_error_expression();
6876
6877         type_t *const orig_type = addr->base.type;
6878         type_t *const type      = skip_typeref(orig_type);
6879
6880         type_t *type_left;
6881         bool    saw_error = false;
6882         if (is_type_pointer(type)) {
6883                 if (!select_left_arrow) {
6884                         errorf(&pos,
6885                                "request for member '%Y' in something not a struct or union, but '%T'",
6886                                symbol, orig_type);
6887                         saw_error = true;
6888                 }
6889                 type_left = skip_typeref(type->pointer.points_to);
6890         } else {
6891                 if (select_left_arrow && is_type_valid(type)) {
6892                         errorf(&pos, "left hand side of '->' is not a pointer, but '%T'", orig_type);
6893                         saw_error = true;
6894                 }
6895                 type_left = type;
6896         }
6897
6898         if (type_left->kind != TYPE_COMPOUND_STRUCT &&
6899             type_left->kind != TYPE_COMPOUND_UNION) {
6900
6901                 if (is_type_valid(type_left) && !saw_error) {
6902                         errorf(&pos,
6903                                "request for member '%Y' in something not a struct or union, but '%T'",
6904                                symbol, type_left);
6905                 }
6906                 return create_error_expression();
6907         }
6908
6909         compound_t *compound = type_left->compound.compound;
6910         if (!compound->complete) {
6911                 errorf(&pos, "request for member '%Y' in incomplete type '%T'",
6912                        symbol, type_left);
6913                 return create_error_expression();
6914         }
6915
6916         type_qualifiers_t  qualifiers = type_left->base.qualifiers;
6917         expression_t      *result     =
6918                 find_create_select(&pos, addr, qualifiers, compound, symbol);
6919
6920         if (result == NULL) {
6921                 errorf(&pos, "'%T' has no member named '%Y'", orig_type, symbol);
6922                 return create_error_expression();
6923         }
6924
6925         return result;
6926 }
6927
6928 static void check_call_argument(type_t          *expected_type,
6929                                 call_argument_t *argument, unsigned pos)
6930 {
6931         type_t         *expected_type_skip = skip_typeref(expected_type);
6932         assign_error_t  error              = ASSIGN_ERROR_INCOMPATIBLE;
6933         expression_t   *arg_expr           = argument->expression;
6934         type_t         *arg_type           = skip_typeref(arg_expr->base.type);
6935
6936         /* handle transparent union gnu extension */
6937         if (is_type_union(expected_type_skip)
6938                         && (get_type_modifiers(expected_type) & DM_TRANSPARENT_UNION)) {
6939                 compound_t *union_decl  = expected_type_skip->compound.compound;
6940                 type_t     *best_type   = NULL;
6941                 entity_t   *entry       = union_decl->members.entities;
6942                 for ( ; entry != NULL; entry = entry->base.next) {
6943                         assert(is_declaration(entry));
6944                         type_t *decl_type = entry->declaration.type;
6945                         error = semantic_assign(decl_type, arg_expr);
6946                         if (error == ASSIGN_ERROR_INCOMPATIBLE
6947                                 || error == ASSIGN_ERROR_POINTER_QUALIFIER_MISSING)
6948                                 continue;
6949
6950                         if (error == ASSIGN_SUCCESS) {
6951                                 best_type = decl_type;
6952                         } else if (best_type == NULL) {
6953                                 best_type = decl_type;
6954                         }
6955                 }
6956
6957                 if (best_type != NULL) {
6958                         expected_type = best_type;
6959                 }
6960         }
6961
6962         error                = semantic_assign(expected_type, arg_expr);
6963         argument->expression = create_implicit_cast(arg_expr, expected_type);
6964
6965         if (error != ASSIGN_SUCCESS) {
6966                 /* report exact scope in error messages (like "in argument 3") */
6967                 char buf[64];
6968                 snprintf(buf, sizeof(buf), "call argument %u", pos);
6969                 report_assign_error(error, expected_type, arg_expr, buf,
6970                                     &arg_expr->base.source_position);
6971         } else {
6972                 type_t *const promoted_type = get_default_promoted_type(arg_type);
6973                 if (!types_compatible(expected_type_skip, promoted_type) &&
6974                     !types_compatible(expected_type_skip, type_void_ptr) &&
6975                     !types_compatible(type_void_ptr,      promoted_type)) {
6976                         /* Deliberately show the skipped types in this warning */
6977                         source_position_t const *const apos = &arg_expr->base.source_position;
6978                         warningf(WARN_TRADITIONAL, apos, "passing call argument %u as '%T' rather than '%T' due to prototype", pos, expected_type_skip, promoted_type);
6979                 }
6980         }
6981 }
6982
6983 /**
6984  * Handle the semantic restrictions of builtin calls
6985  */
6986 static void handle_builtin_argument_restrictions(call_expression_t *call)
6987 {
6988         entity_t *entity = call->function->reference.entity;
6989         switch (entity->function.btk) {
6990         case BUILTIN_FIRM:
6991                 switch (entity->function.b.firm_builtin_kind) {
6992                 case ir_bk_return_address:
6993                 case ir_bk_frame_address: {
6994                         /* argument must be constant */
6995                         call_argument_t *argument = call->arguments;
6996
6997                         if (is_constant_expression(argument->expression) == EXPR_CLASS_VARIABLE) {
6998                                 errorf(&call->base.source_position,
6999                                            "argument of '%Y' must be a constant expression",
7000                                            call->function->reference.entity->base.symbol);
7001                         }
7002                         break;
7003                 }
7004                 case ir_bk_prefetch:
7005                         /* second and third argument must be constant if existent */
7006                         if (call->arguments == NULL)
7007                                 break;
7008                         call_argument_t *rw = call->arguments->next;
7009                         call_argument_t *locality = NULL;
7010
7011                         if (rw != NULL) {
7012                                 if (is_constant_expression(rw->expression) == EXPR_CLASS_VARIABLE) {
7013                                         errorf(&call->base.source_position,
7014                                                    "second argument of '%Y' must be a constant expression",
7015                                                    call->function->reference.entity->base.symbol);
7016                                 }
7017                                 locality = rw->next;
7018                         }
7019                         if (locality != NULL) {
7020                                 if (is_constant_expression(locality->expression) == EXPR_CLASS_VARIABLE) {
7021                                         errorf(&call->base.source_position,
7022                                                    "third argument of '%Y' must be a constant expression",
7023                                                    call->function->reference.entity->base.symbol);
7024                                 }
7025                                 locality = rw->next;
7026                         }
7027                         break;
7028                 default:
7029                         break;
7030                 }
7031
7032         case BUILTIN_OBJECT_SIZE:
7033                 if (call->arguments == NULL)
7034                         break;
7035
7036                 call_argument_t *arg = call->arguments->next;
7037                 if (arg != NULL && is_constant_expression(arg->expression) == EXPR_CLASS_VARIABLE) {
7038                         errorf(&call->base.source_position,
7039                                    "second argument of '%Y' must be a constant expression",
7040                                    call->function->reference.entity->base.symbol);
7041                 }
7042                 break;
7043         default:
7044                 break;
7045         }
7046 }
7047
7048 /**
7049  * Parse a call expression, ie. expression '( ... )'.
7050  *
7051  * @param expression  the function address
7052  */
7053 static expression_t *parse_call_expression(expression_t *expression)
7054 {
7055         expression_t      *result = allocate_expression_zero(EXPR_CALL);
7056         call_expression_t *call   = &result->call;
7057         call->function            = expression;
7058
7059         type_t *const orig_type = expression->base.type;
7060         type_t *const type      = skip_typeref(orig_type);
7061
7062         function_type_t *function_type = NULL;
7063         if (is_type_pointer(type)) {
7064                 type_t *const to_type = skip_typeref(type->pointer.points_to);
7065
7066                 if (is_type_function(to_type)) {
7067                         function_type   = &to_type->function;
7068                         call->base.type = function_type->return_type;
7069                 }
7070         }
7071
7072         if (function_type == NULL && is_type_valid(type)) {
7073                 errorf(HERE,
7074                        "called object '%E' (type '%T') is not a pointer to a function",
7075                        expression, orig_type);
7076         }
7077
7078         /* parse arguments */
7079         eat('(');
7080         add_anchor_token(')');
7081         add_anchor_token(',');
7082
7083         if (token.kind != ')') {
7084                 call_argument_t **anchor = &call->arguments;
7085                 do {
7086                         call_argument_t *argument = allocate_ast_zero(sizeof(*argument));
7087                         argument->expression = parse_assignment_expression();
7088
7089                         *anchor = argument;
7090                         anchor  = &argument->next;
7091                 } while (next_if(','));
7092         }
7093         rem_anchor_token(',');
7094         rem_anchor_token(')');
7095         expect(')');
7096
7097         if (function_type == NULL)
7098                 return result;
7099
7100         /* check type and count of call arguments */
7101         function_parameter_t *parameter = function_type->parameters;
7102         call_argument_t      *argument  = call->arguments;
7103         if (!function_type->unspecified_parameters) {
7104                 for (unsigned pos = 0; parameter != NULL && argument != NULL;
7105                                 parameter = parameter->next, argument = argument->next) {
7106                         check_call_argument(parameter->type, argument, ++pos);
7107                 }
7108
7109                 if (parameter != NULL) {
7110                         errorf(&expression->base.source_position, "too few arguments to function '%E'", expression);
7111                 } else if (argument != NULL && !function_type->variadic) {
7112                         errorf(&argument->expression->base.source_position, "too many arguments to function '%E'", expression);
7113                 }
7114         }
7115
7116         /* do default promotion for other arguments */
7117         for (; argument != NULL; argument = argument->next) {
7118                 type_t *argument_type = argument->expression->base.type;
7119                 if (!is_type_object(skip_typeref(argument_type))) {
7120                         errorf(&argument->expression->base.source_position,
7121                                "call argument '%E' must not be void", argument->expression);
7122                 }
7123
7124                 argument_type = get_default_promoted_type(argument_type);
7125
7126                 argument->expression
7127                         = create_implicit_cast(argument->expression, argument_type);
7128         }
7129
7130         check_format(call);
7131
7132         if (is_type_compound(skip_typeref(function_type->return_type))) {
7133                 source_position_t const *const pos = &expression->base.source_position;
7134                 warningf(WARN_AGGREGATE_RETURN, pos, "function call has aggregate value");
7135         }
7136
7137         if (expression->kind == EXPR_REFERENCE) {
7138                 reference_expression_t *reference = &expression->reference;
7139                 if (reference->entity->kind == ENTITY_FUNCTION &&
7140                     reference->entity->function.btk != BUILTIN_NONE)
7141                         handle_builtin_argument_restrictions(call);
7142         }
7143
7144         return result;
7145 }
7146
7147 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
7148
7149 static bool same_compound_type(const type_t *type1, const type_t *type2)
7150 {
7151         return
7152                 is_type_compound(type1) &&
7153                 type1->kind == type2->kind &&
7154                 type1->compound.compound == type2->compound.compound;
7155 }
7156
7157 static expression_t const *get_reference_address(expression_t const *expr)
7158 {
7159         bool regular_take_address = true;
7160         for (;;) {
7161                 if (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7162                         expr = expr->unary.value;
7163                 } else {
7164                         regular_take_address = false;
7165                 }
7166
7167                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7168                         break;
7169
7170                 expr = expr->unary.value;
7171         }
7172
7173         if (expr->kind != EXPR_REFERENCE)
7174                 return NULL;
7175
7176         /* special case for functions which are automatically converted to a
7177          * pointer to function without an extra TAKE_ADDRESS operation */
7178         if (!regular_take_address &&
7179                         expr->reference.entity->kind != ENTITY_FUNCTION) {
7180                 return NULL;
7181         }
7182
7183         return expr;
7184 }
7185
7186 static void warn_reference_address_as_bool(expression_t const* expr)
7187 {
7188         expr = get_reference_address(expr);
7189         if (expr != NULL) {
7190                 source_position_t const *const pos = &expr->base.source_position;
7191                 entity_t          const *const ent = expr->reference.entity;
7192                 warningf(WARN_ADDRESS, pos, "the address of '%N' will always evaluate as 'true'", ent);
7193         }
7194 }
7195
7196 static void warn_assignment_in_condition(const expression_t *const expr)
7197 {
7198         if (expr->base.kind != EXPR_BINARY_ASSIGN)
7199                 return;
7200         if (expr->base.parenthesized)
7201                 return;
7202         source_position_t const *const pos = &expr->base.source_position;
7203         warningf(WARN_PARENTHESES, pos, "suggest parentheses around assignment used as truth value");
7204 }
7205
7206 static void semantic_condition(expression_t const *const expr,
7207                                char const *const context)
7208 {
7209         type_t *const type = skip_typeref(expr->base.type);
7210         if (is_type_scalar(type)) {
7211                 warn_reference_address_as_bool(expr);
7212                 warn_assignment_in_condition(expr);
7213         } else if (is_type_valid(type)) {
7214                 errorf(&expr->base.source_position,
7215                                 "%s must have scalar type", context);
7216         }
7217 }
7218
7219 /**
7220  * Parse a conditional expression, ie. 'expression ? ... : ...'.
7221  *
7222  * @param expression  the conditional expression
7223  */
7224 static expression_t *parse_conditional_expression(expression_t *expression)
7225 {
7226         expression_t *result = allocate_expression_zero(EXPR_CONDITIONAL);
7227
7228         conditional_expression_t *conditional = &result->conditional;
7229         conditional->condition                = expression;
7230
7231         eat('?');
7232         add_anchor_token(':');
7233
7234         /* §6.5.15:2  The first operand shall have scalar type. */
7235         semantic_condition(expression, "condition of conditional operator");
7236
7237         expression_t *true_expression = expression;
7238         bool          gnu_cond = false;
7239         if (GNU_MODE && token.kind == ':') {
7240                 gnu_cond = true;
7241         } else {
7242                 true_expression = parse_expression();
7243         }
7244         rem_anchor_token(':');
7245         expect(':');
7246         expression_t *false_expression =
7247                 parse_subexpression(c_mode & _CXX ? PREC_ASSIGNMENT : PREC_CONDITIONAL);
7248
7249         type_t *const orig_true_type  = true_expression->base.type;
7250         type_t *const orig_false_type = false_expression->base.type;
7251         type_t *const true_type       = skip_typeref(orig_true_type);
7252         type_t *const false_type      = skip_typeref(orig_false_type);
7253
7254         /* 6.5.15.3 */
7255         source_position_t const *const pos = &conditional->base.source_position;
7256         type_t                        *result_type;
7257         if (is_type_void(true_type) || is_type_void(false_type)) {
7258                 /* ISO/IEC 14882:1998(E) §5.16:2 */
7259                 if (true_expression->kind == EXPR_UNARY_THROW) {
7260                         result_type = false_type;
7261                 } else if (false_expression->kind == EXPR_UNARY_THROW) {
7262                         result_type = true_type;
7263                 } else {
7264                         if (!is_type_void(true_type) || !is_type_void(false_type)) {
7265                                 warningf(WARN_OTHER, pos, "ISO C forbids conditional expression with only one void side");
7266                         }
7267                         result_type = type_void;
7268                 }
7269         } else if (is_type_arithmetic(true_type)
7270                    && is_type_arithmetic(false_type)) {
7271                 result_type = semantic_arithmetic(true_type, false_type);
7272         } else if (same_compound_type(true_type, false_type)) {
7273                 /* just take 1 of the 2 types */
7274                 result_type = true_type;
7275         } else if (is_type_pointer(true_type) || is_type_pointer(false_type)) {
7276                 type_t *pointer_type;
7277                 type_t *other_type;
7278                 expression_t *other_expression;
7279                 if (is_type_pointer(true_type) &&
7280                                 (!is_type_pointer(false_type) || is_null_pointer_constant(false_expression))) {
7281                         pointer_type     = true_type;
7282                         other_type       = false_type;
7283                         other_expression = false_expression;
7284                 } else {
7285                         pointer_type     = false_type;
7286                         other_type       = true_type;
7287                         other_expression = true_expression;
7288                 }
7289
7290                 if (is_null_pointer_constant(other_expression)) {
7291                         result_type = pointer_type;
7292                 } else if (is_type_pointer(other_type)) {
7293                         type_t *to1 = skip_typeref(pointer_type->pointer.points_to);
7294                         type_t *to2 = skip_typeref(other_type->pointer.points_to);
7295
7296                         type_t *to;
7297                         if (is_type_void(to1) || is_type_void(to2)) {
7298                                 to = type_void;
7299                         } else if (types_compatible(get_unqualified_type(to1),
7300                                                     get_unqualified_type(to2))) {
7301                                 to = to1;
7302                         } else {
7303                                 warningf(WARN_OTHER, pos, "pointer types '%T' and '%T' in conditional expression are incompatible", true_type, false_type);
7304                                 to = type_void;
7305                         }
7306
7307                         type_t *const type =
7308                                 get_qualified_type(to, to1->base.qualifiers | to2->base.qualifiers);
7309                         result_type = make_pointer_type(type, TYPE_QUALIFIER_NONE);
7310                 } else if (is_type_integer(other_type)) {
7311                         warningf(WARN_OTHER, pos, "pointer/integer type mismatch in conditional expression ('%T' and '%T')", true_type, false_type);
7312                         result_type = pointer_type;
7313                 } else {
7314                         goto types_incompatible;
7315                 }
7316         } else {
7317 types_incompatible:
7318                 if (is_type_valid(true_type) && is_type_valid(false_type)) {
7319                         type_error_incompatible("while parsing conditional", pos, true_type, false_type);
7320                 }
7321                 result_type = type_error_type;
7322         }
7323
7324         conditional->true_expression
7325                 = gnu_cond ? NULL : create_implicit_cast(true_expression, result_type);
7326         conditional->false_expression
7327                 = create_implicit_cast(false_expression, result_type);
7328         conditional->base.type = result_type;
7329         return result;
7330 }
7331
7332 /**
7333  * Parse an extension expression.
7334  */
7335 static expression_t *parse_extension(void)
7336 {
7337         PUSH_EXTENSION();
7338         expression_t *expression = parse_subexpression(PREC_UNARY);
7339         POP_EXTENSION();
7340         return expression;
7341 }
7342
7343 /**
7344  * Parse a __builtin_classify_type() expression.
7345  */
7346 static expression_t *parse_builtin_classify_type(void)
7347 {
7348         expression_t *result = allocate_expression_zero(EXPR_CLASSIFY_TYPE);
7349         result->base.type    = type_int;
7350
7351         eat(T___builtin_classify_type);
7352
7353         add_anchor_token(')');
7354         expect('(');
7355         expression_t *expression = parse_expression();
7356         rem_anchor_token(')');
7357         expect(')');
7358         result->classify_type.type_expression = expression;
7359
7360         return result;
7361 }
7362
7363 /**
7364  * Parse a delete expression
7365  * ISO/IEC 14882:1998(E) §5.3.5
7366  */
7367 static expression_t *parse_delete(void)
7368 {
7369         expression_t *const result = allocate_expression_zero(EXPR_UNARY_DELETE);
7370         result->base.type          = type_void;
7371
7372         eat(T_delete);
7373
7374         if (next_if('[')) {
7375                 result->kind = EXPR_UNARY_DELETE_ARRAY;
7376                 expect(']');
7377         }
7378
7379         expression_t *const value = parse_subexpression(PREC_CAST);
7380         result->unary.value = value;
7381
7382         type_t *const type = skip_typeref(value->base.type);
7383         if (!is_type_pointer(type)) {
7384                 if (is_type_valid(type)) {
7385                         errorf(&value->base.source_position,
7386                                         "operand of delete must have pointer type");
7387                 }
7388         } else if (is_type_void(skip_typeref(type->pointer.points_to))) {
7389                 source_position_t const *const pos = &value->base.source_position;
7390                 warningf(WARN_OTHER, pos, "deleting 'void*' is undefined");
7391         }
7392
7393         return result;
7394 }
7395
7396 /**
7397  * Parse a throw expression
7398  * ISO/IEC 14882:1998(E) §15:1
7399  */
7400 static expression_t *parse_throw(void)
7401 {
7402         expression_t *const result = allocate_expression_zero(EXPR_UNARY_THROW);
7403         result->base.type          = type_void;
7404
7405         eat(T_throw);
7406
7407         expression_t *value = NULL;
7408         switch (token.kind) {
7409                 EXPRESSION_START {
7410                         value = parse_assignment_expression();
7411                         /* ISO/IEC 14882:1998(E) §15.1:3 */
7412                         type_t *const orig_type = value->base.type;
7413                         type_t *const type      = skip_typeref(orig_type);
7414                         if (is_type_incomplete(type)) {
7415                                 errorf(&value->base.source_position,
7416                                                 "cannot throw object of incomplete type '%T'", orig_type);
7417                         } else if (is_type_pointer(type)) {
7418                                 type_t *const points_to = skip_typeref(type->pointer.points_to);
7419                                 if (is_type_incomplete(points_to) && !is_type_void(points_to)) {
7420                                         errorf(&value->base.source_position,
7421                                                         "cannot throw pointer to incomplete type '%T'", orig_type);
7422                                 }
7423                         }
7424                 }
7425
7426                 default:
7427                         break;
7428         }
7429         result->unary.value = value;
7430
7431         return result;
7432 }
7433
7434 static bool check_pointer_arithmetic(const source_position_t *source_position,
7435                                      type_t *pointer_type,
7436                                      type_t *orig_pointer_type)
7437 {
7438         type_t *points_to = pointer_type->pointer.points_to;
7439         points_to = skip_typeref(points_to);
7440
7441         if (is_type_incomplete(points_to)) {
7442                 if (!GNU_MODE || !is_type_void(points_to)) {
7443                         errorf(source_position,
7444                                "arithmetic with pointer to incomplete type '%T' not allowed",
7445                                orig_pointer_type);
7446                         return false;
7447                 } else {
7448                         warningf(WARN_POINTER_ARITH, source_position, "pointer of type '%T' used in arithmetic", orig_pointer_type);
7449                 }
7450         } else if (is_type_function(points_to)) {
7451                 if (!GNU_MODE) {
7452                         errorf(source_position,
7453                                "arithmetic with pointer to function type '%T' not allowed",
7454                                orig_pointer_type);
7455                         return false;
7456                 } else {
7457                         warningf(WARN_POINTER_ARITH, source_position, "pointer to a function '%T' used in arithmetic", orig_pointer_type);
7458                 }
7459         }
7460         return true;
7461 }
7462
7463 static bool is_lvalue(const expression_t *expression)
7464 {
7465         /* TODO: doesn't seem to be consistent with §6.3.2.1:1 */
7466         switch (expression->kind) {
7467         case EXPR_ARRAY_ACCESS:
7468         case EXPR_COMPOUND_LITERAL:
7469         case EXPR_REFERENCE:
7470         case EXPR_SELECT:
7471         case EXPR_UNARY_DEREFERENCE:
7472                 return true;
7473
7474         default: {
7475                 type_t *type = skip_typeref(expression->base.type);
7476                 return
7477                         /* ISO/IEC 14882:1998(E) §3.10:3 */
7478                         is_type_reference(type) ||
7479                         /* Claim it is an lvalue, if the type is invalid.  There was a parse
7480                          * error before, which maybe prevented properly recognizing it as
7481                          * lvalue. */
7482                         !is_type_valid(type);
7483         }
7484         }
7485 }
7486
7487 static void semantic_incdec(unary_expression_t *expression)
7488 {
7489         type_t *const orig_type = expression->value->base.type;
7490         type_t *const type      = skip_typeref(orig_type);
7491         if (is_type_pointer(type)) {
7492                 if (!check_pointer_arithmetic(&expression->base.source_position,
7493                                               type, orig_type)) {
7494                         return;
7495                 }
7496         } else if (!is_type_real(type) && is_type_valid(type)) {
7497                 /* TODO: improve error message */
7498                 errorf(&expression->base.source_position,
7499                        "operation needs an arithmetic or pointer type");
7500                 return;
7501         }
7502         if (!is_lvalue(expression->value)) {
7503                 /* TODO: improve error message */
7504                 errorf(&expression->base.source_position, "lvalue required as operand");
7505         }
7506         expression->base.type = orig_type;
7507 }
7508
7509 static void promote_unary_int_expr(unary_expression_t *const expr, type_t *const type)
7510 {
7511         type_t *const res_type = promote_integer(type);
7512         expr->base.type = res_type;
7513         expr->value     = create_implicit_cast(expr->value, res_type);
7514 }
7515
7516 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
7517 {
7518         type_t *const orig_type = expression->value->base.type;
7519         type_t *const type      = skip_typeref(orig_type);
7520         if (!is_type_arithmetic(type)) {
7521                 if (is_type_valid(type)) {
7522                         /* TODO: improve error message */
7523                         errorf(&expression->base.source_position,
7524                                 "operation needs an arithmetic type");
7525                 }
7526                 return;
7527         } else if (is_type_integer(type)) {
7528                 promote_unary_int_expr(expression, type);
7529         } else {
7530                 expression->base.type = orig_type;
7531         }
7532 }
7533
7534 static void semantic_unexpr_plus(unary_expression_t *expression)
7535 {
7536         semantic_unexpr_arithmetic(expression);
7537         source_position_t const *const pos = &expression->base.source_position;
7538         warningf(WARN_TRADITIONAL, pos, "traditional C rejects the unary plus operator");
7539 }
7540
7541 static void semantic_not(unary_expression_t *expression)
7542 {
7543         /* §6.5.3.3:1  The operand [...] of the ! operator, scalar type. */
7544         semantic_condition(expression->value, "operand of !");
7545         expression->base.type = c_mode & _CXX ? type_bool : type_int;
7546 }
7547
7548 static void semantic_unexpr_integer(unary_expression_t *expression)
7549 {
7550         type_t *const orig_type = expression->value->base.type;
7551         type_t *const type      = skip_typeref(orig_type);
7552         if (!is_type_integer(type)) {
7553                 if (is_type_valid(type)) {
7554                         errorf(&expression->base.source_position,
7555                                "operand of ~ must be of integer type");
7556                 }
7557                 return;
7558         }
7559
7560         promote_unary_int_expr(expression, type);
7561 }
7562
7563 static void semantic_dereference(unary_expression_t *expression)
7564 {
7565         type_t *const orig_type = expression->value->base.type;
7566         type_t *const type      = skip_typeref(orig_type);
7567         if (!is_type_pointer(type)) {
7568                 if (is_type_valid(type)) {
7569                         errorf(&expression->base.source_position,
7570                                "Unary '*' needs pointer or array type, but type '%T' given", orig_type);
7571                 }
7572                 return;
7573         }
7574
7575         type_t *result_type   = type->pointer.points_to;
7576         result_type           = automatic_type_conversion(result_type);
7577         expression->base.type = result_type;
7578 }
7579
7580 /**
7581  * Record that an address is taken (expression represents an lvalue).
7582  *
7583  * @param expression       the expression
7584  * @param may_be_register  if true, the expression might be an register
7585  */
7586 static void set_address_taken(expression_t *expression, bool may_be_register)
7587 {
7588         if (expression->kind != EXPR_REFERENCE)
7589                 return;
7590
7591         entity_t *const entity = expression->reference.entity;
7592
7593         if (entity->kind != ENTITY_VARIABLE && entity->kind != ENTITY_PARAMETER)
7594                 return;
7595
7596         if (entity->declaration.storage_class == STORAGE_CLASS_REGISTER
7597                         && !may_be_register) {
7598                 source_position_t const *const pos = &expression->base.source_position;
7599                 errorf(pos, "address of register '%N' requested", entity);
7600         }
7601
7602         entity->variable.address_taken = true;
7603 }
7604
7605 /**
7606  * Check the semantic of the address taken expression.
7607  */
7608 static void semantic_take_addr(unary_expression_t *expression)
7609 {
7610         expression_t *value = expression->value;
7611         value->base.type    = revert_automatic_type_conversion(value);
7612
7613         type_t *orig_type = value->base.type;
7614         type_t *type      = skip_typeref(orig_type);
7615         if (!is_type_valid(type))
7616                 return;
7617
7618         /* §6.5.3.2 */
7619         if (!is_lvalue(value)) {
7620                 errorf(&expression->base.source_position, "'&' requires an lvalue");
7621         }
7622         if (is_bitfield(value)) {
7623                 errorf(&expression->base.source_position,
7624                        "'&' not allowed on bitfield");
7625         }
7626
7627         set_address_taken(value, false);
7628
7629         expression->base.type = make_pointer_type(orig_type, TYPE_QUALIFIER_NONE);
7630 }
7631
7632 #define CREATE_UNARY_EXPRESSION_PARSER(token_kind, unexpression_type, sfunc) \
7633 static expression_t *parse_##unexpression_type(void)                         \
7634 {                                                                            \
7635         expression_t *unary_expression                                           \
7636                 = allocate_expression_zero(unexpression_type);                       \
7637         eat(token_kind);                                                         \
7638         unary_expression->unary.value = parse_subexpression(PREC_UNARY);         \
7639                                                                                  \
7640         sfunc(&unary_expression->unary);                                         \
7641                                                                                  \
7642         return unary_expression;                                                 \
7643 }
7644
7645 CREATE_UNARY_EXPRESSION_PARSER('-', EXPR_UNARY_NEGATE,
7646                                semantic_unexpr_arithmetic)
7647 CREATE_UNARY_EXPRESSION_PARSER('+', EXPR_UNARY_PLUS,
7648                                semantic_unexpr_plus)
7649 CREATE_UNARY_EXPRESSION_PARSER('!', EXPR_UNARY_NOT,
7650                                semantic_not)
7651 CREATE_UNARY_EXPRESSION_PARSER('*', EXPR_UNARY_DEREFERENCE,
7652                                semantic_dereference)
7653 CREATE_UNARY_EXPRESSION_PARSER('&', EXPR_UNARY_TAKE_ADDRESS,
7654                                semantic_take_addr)
7655 CREATE_UNARY_EXPRESSION_PARSER('~', EXPR_UNARY_BITWISE_NEGATE,
7656                                semantic_unexpr_integer)
7657 CREATE_UNARY_EXPRESSION_PARSER(T_PLUSPLUS,   EXPR_UNARY_PREFIX_INCREMENT,
7658                                semantic_incdec)
7659 CREATE_UNARY_EXPRESSION_PARSER(T_MINUSMINUS, EXPR_UNARY_PREFIX_DECREMENT,
7660                                semantic_incdec)
7661
7662 #define CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(token_kind, unexpression_type, \
7663                                                sfunc)                         \
7664 static expression_t *parse_##unexpression_type(expression_t *left)            \
7665 {                                                                             \
7666         expression_t *unary_expression                                            \
7667                 = allocate_expression_zero(unexpression_type);                        \
7668         eat(token_kind);                                                          \
7669         unary_expression->unary.value = left;                                     \
7670                                                                                   \
7671         sfunc(&unary_expression->unary);                                          \
7672                                                                               \
7673         return unary_expression;                                                  \
7674 }
7675
7676 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_PLUSPLUS,
7677                                        EXPR_UNARY_POSTFIX_INCREMENT,
7678                                        semantic_incdec)
7679 CREATE_UNARY_POSTFIX_EXPRESSION_PARSER(T_MINUSMINUS,
7680                                        EXPR_UNARY_POSTFIX_DECREMENT,
7681                                        semantic_incdec)
7682
7683 static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
7684 {
7685         /* TODO: handle complex + imaginary types */
7686
7687         type_left  = get_unqualified_type(type_left);
7688         type_right = get_unqualified_type(type_right);
7689
7690         /* §6.3.1.8 Usual arithmetic conversions */
7691         if (type_left == type_long_double || type_right == type_long_double) {
7692                 return type_long_double;
7693         } else if (type_left == type_double || type_right == type_double) {
7694                 return type_double;
7695         } else if (type_left == type_float || type_right == type_float) {
7696                 return type_float;
7697         }
7698
7699         type_left  = promote_integer(type_left);
7700         type_right = promote_integer(type_right);
7701
7702         if (type_left == type_right)
7703                 return type_left;
7704
7705         bool     const signed_left  = is_type_signed(type_left);
7706         bool     const signed_right = is_type_signed(type_right);
7707         unsigned const rank_left    = get_akind_rank(get_akind(type_left));
7708         unsigned const rank_right   = get_akind_rank(get_akind(type_right));
7709
7710         if (signed_left == signed_right)
7711                 return rank_left >= rank_right ? type_left : type_right;
7712
7713         unsigned           s_rank;
7714         unsigned           u_rank;
7715         atomic_type_kind_t s_akind;
7716         atomic_type_kind_t u_akind;
7717         type_t *s_type;
7718         type_t *u_type;
7719         if (signed_left) {
7720                 s_type = type_left;
7721                 u_type = type_right;
7722         } else {
7723                 s_type = type_right;
7724                 u_type = type_left;
7725         }
7726         s_akind = get_akind(s_type);
7727         u_akind = get_akind(u_type);
7728         s_rank  = get_akind_rank(s_akind);
7729         u_rank  = get_akind_rank(u_akind);
7730
7731         if (u_rank >= s_rank)
7732                 return u_type;
7733
7734         if (get_atomic_type_size(s_akind) > get_atomic_type_size(u_akind))
7735                 return s_type;
7736
7737         switch (s_akind) {
7738         case ATOMIC_TYPE_INT:      return type_unsigned_int;
7739         case ATOMIC_TYPE_LONG:     return type_unsigned_long;
7740         case ATOMIC_TYPE_LONGLONG: return type_unsigned_long_long;
7741
7742         default: panic("invalid atomic type");
7743         }
7744 }
7745
7746 /**
7747  * Check the semantic restrictions for a binary expression.
7748  */
7749 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
7750 {
7751         expression_t *const left            = expression->left;
7752         expression_t *const right           = expression->right;
7753         type_t       *const orig_type_left  = left->base.type;
7754         type_t       *const orig_type_right = right->base.type;
7755         type_t       *const type_left       = skip_typeref(orig_type_left);
7756         type_t       *const type_right      = skip_typeref(orig_type_right);
7757
7758         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
7759                 /* TODO: improve error message */
7760                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7761                         errorf(&expression->base.source_position,
7762                                "operation needs arithmetic types");
7763                 }
7764                 return;
7765         }
7766
7767         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7768         expression->left      = create_implicit_cast(left, arithmetic_type);
7769         expression->right     = create_implicit_cast(right, arithmetic_type);
7770         expression->base.type = arithmetic_type;
7771 }
7772
7773 static void semantic_binexpr_integer(binary_expression_t *const expression)
7774 {
7775         expression_t *const left            = expression->left;
7776         expression_t *const right           = expression->right;
7777         type_t       *const orig_type_left  = left->base.type;
7778         type_t       *const orig_type_right = right->base.type;
7779         type_t       *const type_left       = skip_typeref(orig_type_left);
7780         type_t       *const type_right      = skip_typeref(orig_type_right);
7781
7782         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7783                 /* TODO: improve error message */
7784                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7785                         errorf(&expression->base.source_position,
7786                                "operation needs integer types");
7787                 }
7788                 return;
7789         }
7790
7791         type_t *const result_type = semantic_arithmetic(type_left, type_right);
7792         expression->left      = create_implicit_cast(left, result_type);
7793         expression->right     = create_implicit_cast(right, result_type);
7794         expression->base.type = result_type;
7795 }
7796
7797 static void warn_div_by_zero(binary_expression_t const *const expression)
7798 {
7799         if (!is_type_integer(expression->base.type))
7800                 return;
7801
7802         expression_t const *const right = expression->right;
7803         /* The type of the right operand can be different for /= */
7804         if (is_type_integer(right->base.type)                    &&
7805             is_constant_expression(right) == EXPR_CLASS_CONSTANT &&
7806             !fold_constant_to_bool(right)) {
7807                 source_position_t const *const pos = &expression->base.source_position;
7808                 warningf(WARN_DIV_BY_ZERO, pos, "division by zero");
7809         }
7810 }
7811
7812 /**
7813  * Check the semantic restrictions for a div/mod expression.
7814  */
7815 static void semantic_divmod_arithmetic(binary_expression_t *expression)
7816 {
7817         semantic_binexpr_arithmetic(expression);
7818         warn_div_by_zero(expression);
7819 }
7820
7821 static void warn_addsub_in_shift(const expression_t *const expr)
7822 {
7823         if (expr->base.parenthesized)
7824                 return;
7825
7826         char op;
7827         switch (expr->kind) {
7828                 case EXPR_BINARY_ADD: op = '+'; break;
7829                 case EXPR_BINARY_SUB: op = '-'; break;
7830                 default:              return;
7831         }
7832
7833         source_position_t const *const pos = &expr->base.source_position;
7834         warningf(WARN_PARENTHESES, pos, "suggest parentheses around '%c' inside shift", op);
7835 }
7836
7837 static bool semantic_shift(binary_expression_t *expression)
7838 {
7839         expression_t *const left            = expression->left;
7840         expression_t *const right           = expression->right;
7841         type_t       *const orig_type_left  = left->base.type;
7842         type_t       *const orig_type_right = right->base.type;
7843         type_t       *      type_left       = skip_typeref(orig_type_left);
7844         type_t       *      type_right      = skip_typeref(orig_type_right);
7845
7846         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
7847                 /* TODO: improve error message */
7848                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
7849                         errorf(&expression->base.source_position,
7850                                "operands of shift operation must have integer types");
7851                 }
7852                 return false;
7853         }
7854
7855         type_left = promote_integer(type_left);
7856
7857         if (is_constant_expression(right) == EXPR_CLASS_CONSTANT) {
7858                 source_position_t const *const pos   = &right->base.source_position;
7859                 long                     const count = fold_constant_to_int(right);
7860                 if (count < 0) {
7861                         warningf(WARN_OTHER, pos, "shift count must be non-negative");
7862                 } else if ((unsigned long)count >=
7863                                 get_atomic_type_size(type_left->atomic.akind) * 8) {
7864                         warningf(WARN_OTHER, pos, "shift count must be less than type width");
7865                 }
7866         }
7867
7868         type_right        = promote_integer(type_right);
7869         expression->right = create_implicit_cast(right, type_right);
7870
7871         return true;
7872 }
7873
7874 static void semantic_shift_op(binary_expression_t *expression)
7875 {
7876         expression_t *const left  = expression->left;
7877         expression_t *const right = expression->right;
7878
7879         if (!semantic_shift(expression))
7880                 return;
7881
7882         warn_addsub_in_shift(left);
7883         warn_addsub_in_shift(right);
7884
7885         type_t *const orig_type_left = left->base.type;
7886         type_t *      type_left      = skip_typeref(orig_type_left);
7887
7888         type_left             = promote_integer(type_left);
7889         expression->left      = create_implicit_cast(left, type_left);
7890         expression->base.type = type_left;
7891 }
7892
7893 static void semantic_add(binary_expression_t *expression)
7894 {
7895         expression_t *const left            = expression->left;
7896         expression_t *const right           = expression->right;
7897         type_t       *const orig_type_left  = left->base.type;
7898         type_t       *const orig_type_right = right->base.type;
7899         type_t       *const type_left       = skip_typeref(orig_type_left);
7900         type_t       *const type_right      = skip_typeref(orig_type_right);
7901
7902         /* §6.5.6 */
7903         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7904                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7905                 expression->left  = create_implicit_cast(left, arithmetic_type);
7906                 expression->right = create_implicit_cast(right, arithmetic_type);
7907                 expression->base.type = arithmetic_type;
7908         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7909                 check_pointer_arithmetic(&expression->base.source_position,
7910                                          type_left, orig_type_left);
7911                 expression->base.type = type_left;
7912         } else if (is_type_pointer(type_right) && is_type_integer(type_left)) {
7913                 check_pointer_arithmetic(&expression->base.source_position,
7914                                          type_right, orig_type_right);
7915                 expression->base.type = type_right;
7916         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7917                 errorf(&expression->base.source_position,
7918                        "invalid operands to binary + ('%T', '%T')",
7919                        orig_type_left, orig_type_right);
7920         }
7921 }
7922
7923 static void semantic_sub(binary_expression_t *expression)
7924 {
7925         expression_t            *const left            = expression->left;
7926         expression_t            *const right           = expression->right;
7927         type_t                  *const orig_type_left  = left->base.type;
7928         type_t                  *const orig_type_right = right->base.type;
7929         type_t                  *const type_left       = skip_typeref(orig_type_left);
7930         type_t                  *const type_right      = skip_typeref(orig_type_right);
7931         source_position_t const *const pos             = &expression->base.source_position;
7932
7933         /* §5.6.5 */
7934         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
7935                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
7936                 expression->left        = create_implicit_cast(left, arithmetic_type);
7937                 expression->right       = create_implicit_cast(right, arithmetic_type);
7938                 expression->base.type =  arithmetic_type;
7939         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
7940                 check_pointer_arithmetic(&expression->base.source_position,
7941                                          type_left, orig_type_left);
7942                 expression->base.type = type_left;
7943         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
7944                 type_t *const unqual_left  = get_unqualified_type(skip_typeref(type_left->pointer.points_to));
7945                 type_t *const unqual_right = get_unqualified_type(skip_typeref(type_right->pointer.points_to));
7946                 if (!types_compatible(unqual_left, unqual_right)) {
7947                         errorf(pos,
7948                                "subtracting pointers to incompatible types '%T' and '%T'",
7949                                orig_type_left, orig_type_right);
7950                 } else if (!is_type_object(unqual_left)) {
7951                         if (!is_type_void(unqual_left)) {
7952                                 errorf(pos, "subtracting pointers to non-object types '%T'",
7953                                        orig_type_left);
7954                         } else {
7955                                 warningf(WARN_OTHER, pos, "subtracting pointers to void");
7956                         }
7957                 }
7958                 expression->base.type = type_ptrdiff_t;
7959         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
7960                 errorf(pos, "invalid operands of types '%T' and '%T' to binary '-'",
7961                        orig_type_left, orig_type_right);
7962         }
7963 }
7964
7965 static void warn_string_literal_address(expression_t const* expr)
7966 {
7967         while (expr->kind == EXPR_UNARY_TAKE_ADDRESS) {
7968                 expr = expr->unary.value;
7969                 if (expr->kind != EXPR_UNARY_DEREFERENCE)
7970                         return;
7971                 expr = expr->unary.value;
7972         }
7973
7974         if (expr->kind == EXPR_STRING_LITERAL) {
7975                 source_position_t const *const pos = &expr->base.source_position;
7976                 warningf(WARN_ADDRESS, pos, "comparison with string literal results in unspecified behaviour");
7977         }
7978 }
7979
7980 static bool maybe_negative(expression_t const *const expr)
7981 {
7982         switch (is_constant_expression(expr)) {
7983                 case EXPR_CLASS_ERROR:    return false;
7984                 case EXPR_CLASS_CONSTANT: return constant_is_negative(expr);
7985                 default:                  return true;
7986         }
7987 }
7988
7989 static void warn_comparison(source_position_t const *const pos, expression_t const *const expr, expression_t const *const other)
7990 {
7991         warn_string_literal_address(expr);
7992
7993         expression_t const* const ref = get_reference_address(expr);
7994         if (ref != NULL && is_null_pointer_constant(other)) {
7995                 entity_t const *const ent = ref->reference.entity;
7996                 warningf(WARN_ADDRESS, pos, "the address of '%N' will never be NULL", ent);
7997         }
7998
7999         if (!expr->base.parenthesized) {
8000                 switch (expr->base.kind) {
8001                         case EXPR_BINARY_LESS:
8002                         case EXPR_BINARY_GREATER:
8003                         case EXPR_BINARY_LESSEQUAL:
8004                         case EXPR_BINARY_GREATEREQUAL:
8005                         case EXPR_BINARY_NOTEQUAL:
8006                         case EXPR_BINARY_EQUAL:
8007                                 warningf(WARN_PARENTHESES, pos, "comparisons like 'x <= y < z' do not have their mathematical meaning");
8008                                 break;
8009                         default:
8010                                 break;
8011                 }
8012         }
8013 }
8014
8015 /**
8016  * Check the semantics of comparison expressions.
8017  *
8018  * @param expression   The expression to check.
8019  */
8020 static void semantic_comparison(binary_expression_t *expression)
8021 {
8022         source_position_t const *const pos   = &expression->base.source_position;
8023         expression_t            *const left  = expression->left;
8024         expression_t            *const right = expression->right;
8025
8026         warn_comparison(pos, left, right);
8027         warn_comparison(pos, right, left);
8028
8029         type_t *orig_type_left  = left->base.type;
8030         type_t *orig_type_right = right->base.type;
8031         type_t *type_left       = skip_typeref(orig_type_left);
8032         type_t *type_right      = skip_typeref(orig_type_right);
8033
8034         /* TODO non-arithmetic types */
8035         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8036                 type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8037
8038                 /* test for signed vs unsigned compares */
8039                 if (is_type_integer(arithmetic_type)) {
8040                         bool const signed_left  = is_type_signed(type_left);
8041                         bool const signed_right = is_type_signed(type_right);
8042                         if (signed_left != signed_right) {
8043                                 /* FIXME long long needs better const folding magic */
8044                                 /* TODO check whether constant value can be represented by other type */
8045                                 if ((signed_left  && maybe_negative(left)) ||
8046                                                 (signed_right && maybe_negative(right))) {
8047                                         warningf(WARN_SIGN_COMPARE, pos, "comparison between signed and unsigned");
8048                                 }
8049                         }
8050                 }
8051
8052                 expression->left        = create_implicit_cast(left, arithmetic_type);
8053                 expression->right       = create_implicit_cast(right, arithmetic_type);
8054                 expression->base.type   = arithmetic_type;
8055                 if ((expression->base.kind == EXPR_BINARY_EQUAL ||
8056                      expression->base.kind == EXPR_BINARY_NOTEQUAL) &&
8057                     is_type_float(arithmetic_type)) {
8058                         warningf(WARN_FLOAT_EQUAL, pos, "comparing floating point with == or != is unsafe");
8059                 }
8060         } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
8061                 /* TODO check compatibility */
8062         } else if (is_type_pointer(type_left)) {
8063                 expression->right = create_implicit_cast(right, type_left);
8064         } else if (is_type_pointer(type_right)) {
8065                 expression->left = create_implicit_cast(left, type_right);
8066         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8067                 type_error_incompatible("invalid operands in comparison", pos, type_left, type_right);
8068         }
8069         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8070 }
8071
8072 /**
8073  * Checks if a compound type has constant fields.
8074  */
8075 static bool has_const_fields(const compound_type_t *type)
8076 {
8077         compound_t *compound = type->compound;
8078         entity_t   *entry    = compound->members.entities;
8079
8080         for (; entry != NULL; entry = entry->base.next) {
8081                 if (!is_declaration(entry))
8082                         continue;
8083
8084                 const type_t *decl_type = skip_typeref(entry->declaration.type);
8085                 if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
8086                         return true;
8087         }
8088
8089         return false;
8090 }
8091
8092 static bool is_valid_assignment_lhs(expression_t const* const left)
8093 {
8094         type_t *const orig_type_left = revert_automatic_type_conversion(left);
8095         type_t *const type_left      = skip_typeref(orig_type_left);
8096
8097         if (!is_lvalue(left)) {
8098                 errorf(&left->base.source_position, "left hand side '%E' of assignment is not an lvalue",
8099                        left);
8100                 return false;
8101         }
8102
8103         if (left->kind == EXPR_REFERENCE
8104                         && left->reference.entity->kind == ENTITY_FUNCTION) {
8105                 errorf(&left->base.source_position, "cannot assign to function '%E'", left);
8106                 return false;
8107         }
8108
8109         if (is_type_array(type_left)) {
8110                 errorf(&left->base.source_position, "cannot assign to array '%E'", left);
8111                 return false;
8112         }
8113         if (type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
8114                 errorf(&left->base.source_position, "assignment to read-only location '%E' (type '%T')", left,
8115                        orig_type_left);
8116                 return false;
8117         }
8118         if (is_type_incomplete(type_left)) {
8119                 errorf(&left->base.source_position, "left-hand side '%E' of assignment has incomplete type '%T'",
8120                        left, orig_type_left);
8121                 return false;
8122         }
8123         if (is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
8124                 errorf(&left->base.source_position, "cannot assign to '%E' because compound type '%T' has read-only fields",
8125                        left, orig_type_left);
8126                 return false;
8127         }
8128
8129         return true;
8130 }
8131
8132 static void semantic_arithmetic_assign(binary_expression_t *expression)
8133 {
8134         expression_t *left            = expression->left;
8135         expression_t *right           = expression->right;
8136         type_t       *orig_type_left  = left->base.type;
8137         type_t       *orig_type_right = right->base.type;
8138
8139         if (!is_valid_assignment_lhs(left))
8140                 return;
8141
8142         type_t *type_left  = skip_typeref(orig_type_left);
8143         type_t *type_right = skip_typeref(orig_type_right);
8144
8145         if (!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
8146                 /* TODO: improve error message */
8147                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8148                         errorf(&expression->base.source_position,
8149                                "operation needs arithmetic types");
8150                 }
8151                 return;
8152         }
8153
8154         /* combined instructions are tricky. We can't create an implicit cast on
8155          * the left side, because we need the uncasted form for the store.
8156          * The ast2firm pass has to know that left_type must be right_type
8157          * for the arithmetic operation and create a cast by itself */
8158         type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
8159         expression->right       = create_implicit_cast(right, arithmetic_type);
8160         expression->base.type   = type_left;
8161 }
8162
8163 static void semantic_divmod_assign(binary_expression_t *expression)
8164 {
8165         semantic_arithmetic_assign(expression);
8166         warn_div_by_zero(expression);
8167 }
8168
8169 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
8170 {
8171         expression_t *const left            = expression->left;
8172         expression_t *const right           = expression->right;
8173         type_t       *const orig_type_left  = left->base.type;
8174         type_t       *const orig_type_right = right->base.type;
8175         type_t       *const type_left       = skip_typeref(orig_type_left);
8176         type_t       *const type_right      = skip_typeref(orig_type_right);
8177
8178         if (!is_valid_assignment_lhs(left))
8179                 return;
8180
8181         if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
8182                 /* combined instructions are tricky. We can't create an implicit cast on
8183                  * the left side, because we need the uncasted form for the store.
8184                  * The ast2firm pass has to know that left_type must be right_type
8185                  * for the arithmetic operation and create a cast by itself */
8186                 type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
8187                 expression->right     = create_implicit_cast(right, arithmetic_type);
8188                 expression->base.type = type_left;
8189         } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
8190                 check_pointer_arithmetic(&expression->base.source_position,
8191                                          type_left, orig_type_left);
8192                 expression->base.type = type_left;
8193         } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
8194                 errorf(&expression->base.source_position,
8195                        "incompatible types '%T' and '%T' in assignment",
8196                        orig_type_left, orig_type_right);
8197         }
8198 }
8199
8200 static void semantic_integer_assign(binary_expression_t *expression)
8201 {
8202         expression_t *left            = expression->left;
8203         expression_t *right           = expression->right;
8204         type_t       *orig_type_left  = left->base.type;
8205         type_t       *orig_type_right = right->base.type;
8206
8207         if (!is_valid_assignment_lhs(left))
8208                 return;
8209
8210         type_t *type_left  = skip_typeref(orig_type_left);
8211         type_t *type_right = skip_typeref(orig_type_right);
8212
8213         if (!is_type_integer(type_left) || !is_type_integer(type_right)) {
8214                 /* TODO: improve error message */
8215                 if (is_type_valid(type_left) && is_type_valid(type_right)) {
8216                         errorf(&expression->base.source_position,
8217                                "operation needs integer 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_shift_assign(binary_expression_t *expression)
8232 {
8233         expression_t *left           = expression->left;
8234
8235         if (!is_valid_assignment_lhs(left))
8236                 return;
8237
8238         if (!semantic_shift(expression))
8239                 return;
8240
8241         expression->base.type = skip_typeref(left->base.type);
8242 }
8243
8244 static void warn_logical_and_within_or(const expression_t *const expr)
8245 {
8246         if (expr->base.kind != EXPR_BINARY_LOGICAL_AND)
8247                 return;
8248         if (expr->base.parenthesized)
8249                 return;
8250         source_position_t const *const pos = &expr->base.source_position;
8251         warningf(WARN_PARENTHESES, pos, "suggest parentheses around && within ||");
8252 }
8253
8254 /**
8255  * Check the semantic restrictions of a logical expression.
8256  */
8257 static void semantic_logical_op(binary_expression_t *expression)
8258 {
8259         /* §6.5.13:2  Each of the operands shall have scalar type.
8260          * §6.5.14:2  Each of the operands shall have scalar type. */
8261         semantic_condition(expression->left,   "left operand of logical operator");
8262         semantic_condition(expression->right, "right operand of logical operator");
8263         if (expression->base.kind == EXPR_BINARY_LOGICAL_OR) {
8264                 warn_logical_and_within_or(expression->left);
8265                 warn_logical_and_within_or(expression->right);
8266         }
8267         expression->base.type = c_mode & _CXX ? type_bool : type_int;
8268 }
8269
8270 /**
8271  * Check the semantic restrictions of a binary assign expression.
8272  */
8273 static void semantic_binexpr_assign(binary_expression_t *expression)
8274 {
8275         expression_t *left           = expression->left;
8276         type_t       *orig_type_left = left->base.type;
8277
8278         if (!is_valid_assignment_lhs(left))
8279                 return;
8280
8281         assign_error_t error = semantic_assign(orig_type_left, expression->right);
8282         report_assign_error(error, orig_type_left, expression->right,
8283                         "assignment", &left->base.source_position);
8284         expression->right = create_implicit_cast(expression->right, orig_type_left);
8285         expression->base.type = orig_type_left;
8286 }
8287
8288 /**
8289  * Determine if the outermost operation (or parts thereof) of the given
8290  * expression has no effect in order to generate a warning about this fact.
8291  * Therefore in some cases this only examines some of the operands of the
8292  * expression (see comments in the function and examples below).
8293  * Examples:
8294  *   f() + 23;    // warning, because + has no effect
8295  *   x || f();    // no warning, because x controls execution of f()
8296  *   x ? y : f(); // warning, because y has no effect
8297  *   (void)x;     // no warning to be able to suppress the warning
8298  * This function can NOT be used for an "expression has definitely no effect"-
8299  * analysis. */
8300 static bool expression_has_effect(const expression_t *const expr)
8301 {
8302         switch (expr->kind) {
8303                 case EXPR_ERROR:                      return true; /* do NOT warn */
8304                 case EXPR_REFERENCE:                  return false;
8305                 case EXPR_ENUM_CONSTANT:              return false;
8306                 case EXPR_LABEL_ADDRESS:              return false;
8307
8308                 /* suppress the warning for microsoft __noop operations */
8309                 case EXPR_LITERAL_MS_NOOP:            return true;
8310                 case EXPR_LITERAL_BOOLEAN:
8311                 case EXPR_LITERAL_CHARACTER:
8312                 case EXPR_LITERAL_WIDE_CHARACTER:
8313                 case EXPR_LITERAL_INTEGER:
8314                 case EXPR_LITERAL_FLOATINGPOINT:
8315                 case EXPR_STRING_LITERAL:             return false;
8316
8317                 case EXPR_CALL: {
8318                         const call_expression_t *const call = &expr->call;
8319                         if (call->function->kind != EXPR_REFERENCE)
8320                                 return true;
8321
8322                         switch (call->function->reference.entity->function.btk) {
8323                                 /* FIXME: which builtins have no effect? */
8324                                 default:                      return true;
8325                         }
8326                 }
8327
8328                 /* Generate the warning if either the left or right hand side of a
8329                  * conditional expression has no effect */
8330                 case EXPR_CONDITIONAL: {
8331                         conditional_expression_t const *const cond = &expr->conditional;
8332                         expression_t             const *const t    = cond->true_expression;
8333                         return
8334                                 (t == NULL || expression_has_effect(t)) &&
8335                                 expression_has_effect(cond->false_expression);
8336                 }
8337
8338                 case EXPR_SELECT:                     return false;
8339                 case EXPR_ARRAY_ACCESS:               return false;
8340                 case EXPR_SIZEOF:                     return false;
8341                 case EXPR_CLASSIFY_TYPE:              return false;
8342                 case EXPR_ALIGNOF:                    return false;
8343
8344                 case EXPR_FUNCNAME:                   return false;
8345                 case EXPR_BUILTIN_CONSTANT_P:         return false;
8346                 case EXPR_BUILTIN_TYPES_COMPATIBLE_P: return false;
8347                 case EXPR_OFFSETOF:                   return false;
8348                 case EXPR_VA_START:                   return true;
8349                 case EXPR_VA_ARG:                     return true;
8350                 case EXPR_VA_COPY:                    return true;
8351                 case EXPR_STATEMENT:                  return true; // TODO
8352                 case EXPR_COMPOUND_LITERAL:           return false;
8353
8354                 case EXPR_UNARY_NEGATE:               return false;
8355                 case EXPR_UNARY_PLUS:                 return false;
8356                 case EXPR_UNARY_BITWISE_NEGATE:       return false;
8357                 case EXPR_UNARY_NOT:                  return false;
8358                 case EXPR_UNARY_DEREFERENCE:          return false;
8359                 case EXPR_UNARY_TAKE_ADDRESS:         return false;
8360                 case EXPR_UNARY_POSTFIX_INCREMENT:    return true;
8361                 case EXPR_UNARY_POSTFIX_DECREMENT:    return true;
8362                 case EXPR_UNARY_PREFIX_INCREMENT:     return true;
8363                 case EXPR_UNARY_PREFIX_DECREMENT:     return true;
8364
8365                 /* Treat void casts as if they have an effect in order to being able to
8366                  * suppress the warning */
8367                 case EXPR_UNARY_CAST: {
8368                         type_t *const type = skip_typeref(expr->base.type);
8369                         return is_type_void(type);
8370                 }
8371
8372                 case EXPR_UNARY_ASSUME:               return true;
8373                 case EXPR_UNARY_DELETE:               return true;
8374                 case EXPR_UNARY_DELETE_ARRAY:         return true;
8375                 case EXPR_UNARY_THROW:                return true;
8376
8377                 case EXPR_BINARY_ADD:                 return false;
8378                 case EXPR_BINARY_SUB:                 return false;
8379                 case EXPR_BINARY_MUL:                 return false;
8380                 case EXPR_BINARY_DIV:                 return false;
8381                 case EXPR_BINARY_MOD:                 return false;
8382                 case EXPR_BINARY_EQUAL:               return false;
8383                 case EXPR_BINARY_NOTEQUAL:            return false;
8384                 case EXPR_BINARY_LESS:                return false;
8385                 case EXPR_BINARY_LESSEQUAL:           return false;
8386                 case EXPR_BINARY_GREATER:             return false;
8387                 case EXPR_BINARY_GREATEREQUAL:        return false;
8388                 case EXPR_BINARY_BITWISE_AND:         return false;
8389                 case EXPR_BINARY_BITWISE_OR:          return false;
8390                 case EXPR_BINARY_BITWISE_XOR:         return false;
8391                 case EXPR_BINARY_SHIFTLEFT:           return false;
8392                 case EXPR_BINARY_SHIFTRIGHT:          return false;
8393                 case EXPR_BINARY_ASSIGN:              return true;
8394                 case EXPR_BINARY_MUL_ASSIGN:          return true;
8395                 case EXPR_BINARY_DIV_ASSIGN:          return true;
8396                 case EXPR_BINARY_MOD_ASSIGN:          return true;
8397                 case EXPR_BINARY_ADD_ASSIGN:          return true;
8398                 case EXPR_BINARY_SUB_ASSIGN:          return true;
8399                 case EXPR_BINARY_SHIFTLEFT_ASSIGN:    return true;
8400                 case EXPR_BINARY_SHIFTRIGHT_ASSIGN:   return true;
8401                 case EXPR_BINARY_BITWISE_AND_ASSIGN:  return true;
8402                 case EXPR_BINARY_BITWISE_XOR_ASSIGN:  return true;
8403                 case EXPR_BINARY_BITWISE_OR_ASSIGN:   return true;
8404
8405                 /* Only examine the right hand side of && and ||, because the left hand
8406                  * side already has the effect of controlling the execution of the right
8407                  * hand side */
8408                 case EXPR_BINARY_LOGICAL_AND:
8409                 case EXPR_BINARY_LOGICAL_OR:
8410                 /* Only examine the right hand side of a comma expression, because the left
8411                  * hand side has a separate warning */
8412                 case EXPR_BINARY_COMMA:
8413                         return expression_has_effect(expr->binary.right);
8414
8415                 case EXPR_BINARY_ISGREATER:           return false;
8416                 case EXPR_BINARY_ISGREATEREQUAL:      return false;
8417                 case EXPR_BINARY_ISLESS:              return false;
8418                 case EXPR_BINARY_ISLESSEQUAL:         return false;
8419                 case EXPR_BINARY_ISLESSGREATER:       return false;
8420                 case EXPR_BINARY_ISUNORDERED:         return false;
8421         }
8422
8423         internal_errorf(HERE, "unexpected expression");
8424 }
8425
8426 static void semantic_comma(binary_expression_t *expression)
8427 {
8428         const expression_t *const left = expression->left;
8429         if (!expression_has_effect(left)) {
8430                 source_position_t const *const pos = &left->base.source_position;
8431                 warningf(WARN_UNUSED_VALUE, pos, "left-hand operand of comma expression has no effect");
8432         }
8433         expression->base.type = expression->right->base.type;
8434 }
8435
8436 /**
8437  * @param prec_r precedence of the right operand
8438  */
8439 #define CREATE_BINEXPR_PARSER(token_kind, binexpression_type, prec_r, sfunc) \
8440 static expression_t *parse_##binexpression_type(expression_t *left)          \
8441 {                                                                            \
8442         expression_t *binexpr = allocate_expression_zero(binexpression_type);    \
8443         binexpr->binary.left  = left;                                            \
8444         eat(token_kind);                                                         \
8445                                                                              \
8446         expression_t *right = parse_subexpression(prec_r);                       \
8447                                                                              \
8448         binexpr->binary.right = right;                                           \
8449         sfunc(&binexpr->binary);                                                 \
8450                                                                              \
8451         return binexpr;                                                          \
8452 }
8453
8454 CREATE_BINEXPR_PARSER('*',                    EXPR_BINARY_MUL,                PREC_CAST,           semantic_binexpr_arithmetic)
8455 CREATE_BINEXPR_PARSER('/',                    EXPR_BINARY_DIV,                PREC_CAST,           semantic_divmod_arithmetic)
8456 CREATE_BINEXPR_PARSER('%',                    EXPR_BINARY_MOD,                PREC_CAST,           semantic_divmod_arithmetic)
8457 CREATE_BINEXPR_PARSER('+',                    EXPR_BINARY_ADD,                PREC_MULTIPLICATIVE, semantic_add)
8458 CREATE_BINEXPR_PARSER('-',                    EXPR_BINARY_SUB,                PREC_MULTIPLICATIVE, semantic_sub)
8459 CREATE_BINEXPR_PARSER(T_LESSLESS,             EXPR_BINARY_SHIFTLEFT,          PREC_ADDITIVE,       semantic_shift_op)
8460 CREATE_BINEXPR_PARSER(T_GREATERGREATER,       EXPR_BINARY_SHIFTRIGHT,         PREC_ADDITIVE,       semantic_shift_op)
8461 CREATE_BINEXPR_PARSER('<',                    EXPR_BINARY_LESS,               PREC_SHIFT,          semantic_comparison)
8462 CREATE_BINEXPR_PARSER('>',                    EXPR_BINARY_GREATER,            PREC_SHIFT,          semantic_comparison)
8463 CREATE_BINEXPR_PARSER(T_LESSEQUAL,            EXPR_BINARY_LESSEQUAL,          PREC_SHIFT,          semantic_comparison)
8464 CREATE_BINEXPR_PARSER(T_GREATEREQUAL,         EXPR_BINARY_GREATEREQUAL,       PREC_SHIFT,          semantic_comparison)
8465 CREATE_BINEXPR_PARSER(T_EXCLAMATIONMARKEQUAL, EXPR_BINARY_NOTEQUAL,           PREC_RELATIONAL,     semantic_comparison)
8466 CREATE_BINEXPR_PARSER(T_EQUALEQUAL,           EXPR_BINARY_EQUAL,              PREC_RELATIONAL,     semantic_comparison)
8467 CREATE_BINEXPR_PARSER('&',                    EXPR_BINARY_BITWISE_AND,        PREC_EQUALITY,       semantic_binexpr_integer)
8468 CREATE_BINEXPR_PARSER('^',                    EXPR_BINARY_BITWISE_XOR,        PREC_AND,            semantic_binexpr_integer)
8469 CREATE_BINEXPR_PARSER('|',                    EXPR_BINARY_BITWISE_OR,         PREC_XOR,            semantic_binexpr_integer)
8470 CREATE_BINEXPR_PARSER(T_ANDAND,               EXPR_BINARY_LOGICAL_AND,        PREC_OR,             semantic_logical_op)
8471 CREATE_BINEXPR_PARSER(T_PIPEPIPE,             EXPR_BINARY_LOGICAL_OR,         PREC_LOGICAL_AND,    semantic_logical_op)
8472 CREATE_BINEXPR_PARSER('=',                    EXPR_BINARY_ASSIGN,             PREC_ASSIGNMENT,     semantic_binexpr_assign)
8473 CREATE_BINEXPR_PARSER(T_PLUSEQUAL,            EXPR_BINARY_ADD_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8474 CREATE_BINEXPR_PARSER(T_MINUSEQUAL,           EXPR_BINARY_SUB_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_addsubb_assign)
8475 CREATE_BINEXPR_PARSER(T_ASTERISKEQUAL,        EXPR_BINARY_MUL_ASSIGN,         PREC_ASSIGNMENT,     semantic_arithmetic_assign)
8476 CREATE_BINEXPR_PARSER(T_SLASHEQUAL,           EXPR_BINARY_DIV_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8477 CREATE_BINEXPR_PARSER(T_PERCENTEQUAL,         EXPR_BINARY_MOD_ASSIGN,         PREC_ASSIGNMENT,     semantic_divmod_assign)
8478 CREATE_BINEXPR_PARSER(T_LESSLESSEQUAL,        EXPR_BINARY_SHIFTLEFT_ASSIGN,   PREC_ASSIGNMENT,     semantic_shift_assign)
8479 CREATE_BINEXPR_PARSER(T_GREATERGREATEREQUAL,  EXPR_BINARY_SHIFTRIGHT_ASSIGN,  PREC_ASSIGNMENT,     semantic_shift_assign)
8480 CREATE_BINEXPR_PARSER(T_ANDEQUAL,             EXPR_BINARY_BITWISE_AND_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8481 CREATE_BINEXPR_PARSER(T_PIPEEQUAL,            EXPR_BINARY_BITWISE_OR_ASSIGN,  PREC_ASSIGNMENT,     semantic_integer_assign)
8482 CREATE_BINEXPR_PARSER(T_CARETEQUAL,           EXPR_BINARY_BITWISE_XOR_ASSIGN, PREC_ASSIGNMENT,     semantic_integer_assign)
8483 CREATE_BINEXPR_PARSER(',',                    EXPR_BINARY_COMMA,              PREC_ASSIGNMENT,     semantic_comma)
8484
8485
8486 static expression_t *parse_subexpression(precedence_t precedence)
8487 {
8488         expression_parser_function_t *parser
8489                 = &expression_parsers[token.kind];
8490         expression_t                 *left;
8491
8492         if (parser->parser != NULL) {
8493                 left = parser->parser();
8494         } else {
8495                 left = parse_primary_expression();
8496         }
8497         assert(left != NULL);
8498
8499         while (true) {
8500                 parser = &expression_parsers[token.kind];
8501                 if (parser->infix_parser == NULL)
8502                         break;
8503                 if (parser->infix_precedence < precedence)
8504                         break;
8505
8506                 left = parser->infix_parser(left);
8507
8508                 assert(left != NULL);
8509         }
8510
8511         return left;
8512 }
8513
8514 /**
8515  * Parse an expression.
8516  */
8517 static expression_t *parse_expression(void)
8518 {
8519         return parse_subexpression(PREC_EXPRESSION);
8520 }
8521
8522 /**
8523  * Register a parser for a prefix-like operator.
8524  *
8525  * @param parser      the parser function
8526  * @param token_kind  the token type of the prefix token
8527  */
8528 static void register_expression_parser(parse_expression_function parser,
8529                                        int token_kind)
8530 {
8531         expression_parser_function_t *entry = &expression_parsers[token_kind];
8532
8533         if (entry->parser != NULL) {
8534                 diagnosticf("for token '%k'\n", (token_kind_t)token_kind);
8535                 panic("trying to register multiple expression parsers for a token");
8536         }
8537         entry->parser = parser;
8538 }
8539
8540 /**
8541  * Register a parser for an infix operator with given precedence.
8542  *
8543  * @param parser      the parser function
8544  * @param token_kind  the token type of the infix operator
8545  * @param precedence  the precedence of the operator
8546  */
8547 static void register_infix_parser(parse_expression_infix_function parser,
8548                                   int token_kind, precedence_t precedence)
8549 {
8550         expression_parser_function_t *entry = &expression_parsers[token_kind];
8551
8552         if (entry->infix_parser != NULL) {
8553                 diagnosticf("for token '%k'\n", (token_kind_t)token_kind);
8554                 panic("trying to register multiple infix expression parsers for a "
8555                       "token");
8556         }
8557         entry->infix_parser     = parser;
8558         entry->infix_precedence = precedence;
8559 }
8560
8561 /**
8562  * Initialize the expression parsers.
8563  */
8564 static void init_expression_parsers(void)
8565 {
8566         memset(&expression_parsers, 0, sizeof(expression_parsers));
8567
8568         register_infix_parser(parse_array_expression,               '[',                    PREC_POSTFIX);
8569         register_infix_parser(parse_call_expression,                '(',                    PREC_POSTFIX);
8570         register_infix_parser(parse_select_expression,              '.',                    PREC_POSTFIX);
8571         register_infix_parser(parse_select_expression,              T_MINUSGREATER,         PREC_POSTFIX);
8572         register_infix_parser(parse_EXPR_UNARY_POSTFIX_INCREMENT,   T_PLUSPLUS,             PREC_POSTFIX);
8573         register_infix_parser(parse_EXPR_UNARY_POSTFIX_DECREMENT,   T_MINUSMINUS,           PREC_POSTFIX);
8574         register_infix_parser(parse_EXPR_BINARY_MUL,                '*',                    PREC_MULTIPLICATIVE);
8575         register_infix_parser(parse_EXPR_BINARY_DIV,                '/',                    PREC_MULTIPLICATIVE);
8576         register_infix_parser(parse_EXPR_BINARY_MOD,                '%',                    PREC_MULTIPLICATIVE);
8577         register_infix_parser(parse_EXPR_BINARY_ADD,                '+',                    PREC_ADDITIVE);
8578         register_infix_parser(parse_EXPR_BINARY_SUB,                '-',                    PREC_ADDITIVE);
8579         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT,          T_LESSLESS,             PREC_SHIFT);
8580         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT,         T_GREATERGREATER,       PREC_SHIFT);
8581         register_infix_parser(parse_EXPR_BINARY_LESS,               '<',                    PREC_RELATIONAL);
8582         register_infix_parser(parse_EXPR_BINARY_GREATER,            '>',                    PREC_RELATIONAL);
8583         register_infix_parser(parse_EXPR_BINARY_LESSEQUAL,          T_LESSEQUAL,            PREC_RELATIONAL);
8584         register_infix_parser(parse_EXPR_BINARY_GREATEREQUAL,       T_GREATEREQUAL,         PREC_RELATIONAL);
8585         register_infix_parser(parse_EXPR_BINARY_EQUAL,              T_EQUALEQUAL,           PREC_EQUALITY);
8586         register_infix_parser(parse_EXPR_BINARY_NOTEQUAL,           T_EXCLAMATIONMARKEQUAL, PREC_EQUALITY);
8587         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND,        '&',                    PREC_AND);
8588         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR,        '^',                    PREC_XOR);
8589         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR,         '|',                    PREC_OR);
8590         register_infix_parser(parse_EXPR_BINARY_LOGICAL_AND,        T_ANDAND,               PREC_LOGICAL_AND);
8591         register_infix_parser(parse_EXPR_BINARY_LOGICAL_OR,         T_PIPEPIPE,             PREC_LOGICAL_OR);
8592         register_infix_parser(parse_conditional_expression,         '?',                    PREC_CONDITIONAL);
8593         register_infix_parser(parse_EXPR_BINARY_ASSIGN,             '=',                    PREC_ASSIGNMENT);
8594         register_infix_parser(parse_EXPR_BINARY_ADD_ASSIGN,         T_PLUSEQUAL,            PREC_ASSIGNMENT);
8595         register_infix_parser(parse_EXPR_BINARY_SUB_ASSIGN,         T_MINUSEQUAL,           PREC_ASSIGNMENT);
8596         register_infix_parser(parse_EXPR_BINARY_MUL_ASSIGN,         T_ASTERISKEQUAL,        PREC_ASSIGNMENT);
8597         register_infix_parser(parse_EXPR_BINARY_DIV_ASSIGN,         T_SLASHEQUAL,           PREC_ASSIGNMENT);
8598         register_infix_parser(parse_EXPR_BINARY_MOD_ASSIGN,         T_PERCENTEQUAL,         PREC_ASSIGNMENT);
8599         register_infix_parser(parse_EXPR_BINARY_SHIFTLEFT_ASSIGN,   T_LESSLESSEQUAL,        PREC_ASSIGNMENT);
8600         register_infix_parser(parse_EXPR_BINARY_SHIFTRIGHT_ASSIGN,  T_GREATERGREATEREQUAL,  PREC_ASSIGNMENT);
8601         register_infix_parser(parse_EXPR_BINARY_BITWISE_AND_ASSIGN, T_ANDEQUAL,             PREC_ASSIGNMENT);
8602         register_infix_parser(parse_EXPR_BINARY_BITWISE_OR_ASSIGN,  T_PIPEEQUAL,            PREC_ASSIGNMENT);
8603         register_infix_parser(parse_EXPR_BINARY_BITWISE_XOR_ASSIGN, T_CARETEQUAL,           PREC_ASSIGNMENT);
8604         register_infix_parser(parse_EXPR_BINARY_COMMA,              ',',                    PREC_EXPRESSION);
8605
8606         register_expression_parser(parse_EXPR_UNARY_NEGATE,           '-');
8607         register_expression_parser(parse_EXPR_UNARY_PLUS,             '+');
8608         register_expression_parser(parse_EXPR_UNARY_NOT,              '!');
8609         register_expression_parser(parse_EXPR_UNARY_BITWISE_NEGATE,   '~');
8610         register_expression_parser(parse_EXPR_UNARY_DEREFERENCE,      '*');
8611         register_expression_parser(parse_EXPR_UNARY_TAKE_ADDRESS,     '&');
8612         register_expression_parser(parse_EXPR_UNARY_PREFIX_INCREMENT, T_PLUSPLUS);
8613         register_expression_parser(parse_EXPR_UNARY_PREFIX_DECREMENT, T_MINUSMINUS);
8614         register_expression_parser(parse_sizeof,                      T_sizeof);
8615         register_expression_parser(parse_alignof,                     T___alignof__);
8616         register_expression_parser(parse_extension,                   T___extension__);
8617         register_expression_parser(parse_builtin_classify_type,       T___builtin_classify_type);
8618         register_expression_parser(parse_delete,                      T_delete);
8619         register_expression_parser(parse_throw,                       T_throw);
8620 }
8621
8622 /**
8623  * Parse a asm statement arguments specification.
8624  */
8625 static asm_argument_t *parse_asm_arguments(bool is_out)
8626 {
8627         asm_argument_t  *result = NULL;
8628         asm_argument_t **anchor = &result;
8629
8630         while (token.kind == T_STRING_LITERAL || token.kind == '[') {
8631                 asm_argument_t *argument = allocate_ast_zero(sizeof(argument[0]));
8632
8633                 if (next_if('[')) {
8634                         add_anchor_token(']');
8635                         argument->symbol = expect_identifier("while parsing asm argument", NULL);
8636                         rem_anchor_token(']');
8637                         expect(']');
8638                         if (!argument->symbol)
8639                                 return NULL;
8640                 }
8641
8642                 argument->constraints = parse_string_literals("asm argument");
8643                 add_anchor_token(')');
8644                 expect('(');
8645                 expression_t *expression = parse_expression();
8646                 rem_anchor_token(')');
8647                 if (is_out) {
8648                         /* Ugly GCC stuff: Allow lvalue casts.  Skip casts, when they do not
8649                          * change size or type representation (e.g. int -> long is ok, but
8650                          * int -> float is not) */
8651                         if (expression->kind == EXPR_UNARY_CAST) {
8652                                 type_t      *const type = expression->base.type;
8653                                 type_kind_t  const kind = type->kind;
8654                                 if (kind == TYPE_ATOMIC || kind == TYPE_POINTER) {
8655                                         unsigned flags;
8656                                         unsigned size;
8657                                         if (kind == TYPE_ATOMIC) {
8658                                                 atomic_type_kind_t const akind = type->atomic.akind;
8659                                                 flags = get_atomic_type_flags(akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8660                                                 size  = get_atomic_type_size(akind);
8661                                         } else {
8662                                                 flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8663                                                 size  = get_type_size(type_void_ptr);
8664                                         }
8665
8666                                         do {
8667                                                 expression_t *const value      = expression->unary.value;
8668                                                 type_t       *const value_type = value->base.type;
8669                                                 type_kind_t   const value_kind = value_type->kind;
8670
8671                                                 unsigned value_flags;
8672                                                 unsigned value_size;
8673                                                 if (value_kind == TYPE_ATOMIC) {
8674                                                         atomic_type_kind_t const value_akind = value_type->atomic.akind;
8675                                                         value_flags = get_atomic_type_flags(value_akind) & ~ATOMIC_TYPE_FLAG_SIGNED;
8676                                                         value_size  = get_atomic_type_size(value_akind);
8677                                                 } else if (value_kind == TYPE_POINTER) {
8678                                                         value_flags = ATOMIC_TYPE_FLAG_INTEGER | ATOMIC_TYPE_FLAG_ARITHMETIC;
8679                                                         value_size  = get_type_size(type_void_ptr);
8680                                                 } else {
8681                                                         break;
8682                                                 }
8683
8684                                                 if (value_flags != flags || value_size != size)
8685                                                         break;
8686
8687                                                 expression = value;
8688                                         } while (expression->kind == EXPR_UNARY_CAST);
8689                                 }
8690                         }
8691
8692                         if (!is_lvalue(expression)) {
8693                                 errorf(&expression->base.source_position,
8694                                        "asm output argument is not an lvalue");
8695                         }
8696
8697                         if (argument->constraints.begin[0] == '=')
8698                                 determine_lhs_ent(expression, NULL);
8699                         else
8700                                 mark_vars_read(expression, NULL);
8701                 } else {
8702                         mark_vars_read(expression, NULL);
8703                 }
8704                 argument->expression = expression;
8705                 expect(')');
8706
8707                 set_address_taken(expression, true);
8708
8709                 *anchor = argument;
8710                 anchor  = &argument->next;
8711
8712                 if (!next_if(','))
8713                         break;
8714         }
8715
8716         return result;
8717 }
8718
8719 /**
8720  * Parse a asm statement clobber specification.
8721  */
8722 static asm_clobber_t *parse_asm_clobbers(void)
8723 {
8724         asm_clobber_t *result  = NULL;
8725         asm_clobber_t **anchor = &result;
8726
8727         while (token.kind == T_STRING_LITERAL) {
8728                 asm_clobber_t *clobber = allocate_ast_zero(sizeof(clobber[0]));
8729                 clobber->clobber       = parse_string_literals(NULL);
8730
8731                 *anchor = clobber;
8732                 anchor  = &clobber->next;
8733
8734                 if (!next_if(','))
8735                         break;
8736         }
8737
8738         return result;
8739 }
8740
8741 /**
8742  * Parse an asm statement.
8743  */
8744 static statement_t *parse_asm_statement(void)
8745 {
8746         statement_t     *statement     = allocate_statement_zero(STATEMENT_ASM);
8747         asm_statement_t *asm_statement = &statement->asms;
8748
8749         eat(T_asm);
8750         add_anchor_token(')');
8751         add_anchor_token(':');
8752         add_anchor_token(T_STRING_LITERAL);
8753
8754         if (next_if(T_volatile))
8755                 asm_statement->is_volatile = true;
8756
8757         expect('(');
8758         rem_anchor_token(T_STRING_LITERAL);
8759         asm_statement->asm_text = parse_string_literals("asm statement");
8760
8761         if (next_if(':'))
8762                 asm_statement->outputs = parse_asm_arguments(true);
8763
8764         if (next_if(':'))
8765                 asm_statement->inputs = parse_asm_arguments(false);
8766
8767         rem_anchor_token(':');
8768         if (next_if(':'))
8769                 asm_statement->clobbers = parse_asm_clobbers();
8770
8771         rem_anchor_token(')');
8772         expect(')');
8773         expect(';');
8774
8775         if (asm_statement->outputs == NULL) {
8776                 /* GCC: An 'asm' instruction without any output operands will be treated
8777                  * identically to a volatile 'asm' instruction. */
8778                 asm_statement->is_volatile = true;
8779         }
8780
8781         return statement;
8782 }
8783
8784 static statement_t *parse_label_inner_statement(statement_t const *const label, char const *const label_kind)
8785 {
8786         statement_t *inner_stmt;
8787         switch (token.kind) {
8788                 case '}':
8789                         errorf(&label->base.source_position, "%s at end of compound statement", label_kind);
8790                         inner_stmt = create_error_statement();
8791                         break;
8792
8793                 case ';':
8794                         if (label->kind == STATEMENT_LABEL) {
8795                                 /* Eat an empty statement here, to avoid the warning about an empty
8796                                  * statement after a label.  label:; is commonly used to have a label
8797                                  * before a closing brace. */
8798                                 inner_stmt = create_empty_statement();
8799                                 eat(';');
8800                                 break;
8801                         }
8802                         /* FALLTHROUGH */
8803
8804                 default:
8805                         inner_stmt = parse_statement();
8806                         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
8807                         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
8808                         if (inner_stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
8809                                 errorf(&inner_stmt->base.source_position, "declaration after %s", label_kind);
8810                         }
8811                         break;
8812         }
8813         return inner_stmt;
8814 }
8815
8816 /**
8817  * Parse a case statement.
8818  */
8819 static statement_t *parse_case_statement(void)
8820 {
8821         statement_t       *const statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8822         source_position_t *const pos       = &statement->base.source_position;
8823
8824         eat(T_case);
8825         add_anchor_token(':');
8826
8827         expression_t *expression = parse_expression();
8828         type_t *expression_type = expression->base.type;
8829         type_t *skipped         = skip_typeref(expression_type);
8830         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8831                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8832                        expression, expression_type);
8833         }
8834
8835         type_t *type = expression_type;
8836         if (current_switch != NULL) {
8837                 type_t *switch_type = current_switch->expression->base.type;
8838                 if (is_type_valid(switch_type)) {
8839                         expression = create_implicit_cast(expression, switch_type);
8840                 }
8841         }
8842
8843         statement->case_label.expression = expression;
8844         expression_classification_t const expr_class = is_constant_expression(expression);
8845         if (expr_class != EXPR_CLASS_CONSTANT) {
8846                 if (expr_class != EXPR_CLASS_ERROR) {
8847                         errorf(pos, "case label does not reduce to an integer constant");
8848                 }
8849                 statement->case_label.is_bad = true;
8850         } else {
8851                 long const val = fold_constant_to_int(expression);
8852                 statement->case_label.first_case = val;
8853                 statement->case_label.last_case  = val;
8854         }
8855
8856         if (GNU_MODE) {
8857                 if (next_if(T_DOTDOTDOT)) {
8858                         expression_t *end_range = parse_expression();
8859                         expression_type = expression->base.type;
8860                         skipped         = skip_typeref(expression_type);
8861                         if (!is_type_integer(skipped) && is_type_valid(skipped)) {
8862                                 errorf(pos, "case expression '%E' must have integer type but has type '%T'",
8863                                            expression, expression_type);
8864                         }
8865
8866                         end_range = create_implicit_cast(end_range, type);
8867                         statement->case_label.end_range = end_range;
8868                         expression_classification_t const end_class = is_constant_expression(end_range);
8869                         if (end_class != EXPR_CLASS_CONSTANT) {
8870                                 if (end_class != EXPR_CLASS_ERROR) {
8871                                         errorf(pos, "case range does not reduce to an integer constant");
8872                                 }
8873                                 statement->case_label.is_bad = true;
8874                         } else {
8875                                 long const val = fold_constant_to_int(end_range);
8876                                 statement->case_label.last_case = val;
8877
8878                                 if (val < statement->case_label.first_case) {
8879                                         statement->case_label.is_empty_range = true;
8880                                         warningf(WARN_OTHER, pos, "empty range specified");
8881                                 }
8882                         }
8883                 }
8884         }
8885
8886         PUSH_PARENT(statement);
8887
8888         rem_anchor_token(':');
8889         expect(':');
8890
8891         if (current_switch != NULL) {
8892                 if (! statement->case_label.is_bad) {
8893                         /* Check for duplicate case values */
8894                         case_label_statement_t *c = &statement->case_label;
8895                         for (case_label_statement_t *l = current_switch->first_case; l != NULL; l = l->next) {
8896                                 if (l->is_bad || l->is_empty_range || l->expression == NULL)
8897                                         continue;
8898
8899                                 if (c->last_case < l->first_case || c->first_case > l->last_case)
8900                                         continue;
8901
8902                                 errorf(pos, "duplicate case value (previously used %P)",
8903                                        &l->base.source_position);
8904                                 break;
8905                         }
8906                 }
8907                 /* link all cases into the switch statement */
8908                 if (current_switch->last_case == NULL) {
8909                         current_switch->first_case      = &statement->case_label;
8910                 } else {
8911                         current_switch->last_case->next = &statement->case_label;
8912                 }
8913                 current_switch->last_case = &statement->case_label;
8914         } else {
8915                 errorf(pos, "case label not within a switch statement");
8916         }
8917
8918         statement->case_label.statement = parse_label_inner_statement(statement, "case label");
8919
8920         POP_PARENT();
8921         return statement;
8922 }
8923
8924 /**
8925  * Parse a default statement.
8926  */
8927 static statement_t *parse_default_statement(void)
8928 {
8929         statement_t *statement = allocate_statement_zero(STATEMENT_CASE_LABEL);
8930
8931         eat(T_default);
8932
8933         PUSH_PARENT(statement);
8934
8935         expect(':');
8936
8937         if (current_switch != NULL) {
8938                 const case_label_statement_t *def_label = current_switch->default_label;
8939                 if (def_label != NULL) {
8940                         errorf(&statement->base.source_position, "multiple default labels in one switch (previous declared %P)", &def_label->base.source_position);
8941                 } else {
8942                         current_switch->default_label = &statement->case_label;
8943
8944                         /* link all cases into the switch statement */
8945                         if (current_switch->last_case == NULL) {
8946                                 current_switch->first_case      = &statement->case_label;
8947                         } else {
8948                                 current_switch->last_case->next = &statement->case_label;
8949                         }
8950                         current_switch->last_case = &statement->case_label;
8951                 }
8952         } else {
8953                 errorf(&statement->base.source_position,
8954                         "'default' label not within a switch statement");
8955         }
8956
8957         statement->case_label.statement = parse_label_inner_statement(statement, "default label");
8958
8959         POP_PARENT();
8960         return statement;
8961 }
8962
8963 /**
8964  * Parse a label statement.
8965  */
8966 static statement_t *parse_label_statement(void)
8967 {
8968         statement_t *const statement = allocate_statement_zero(STATEMENT_LABEL);
8969         label_t     *const label     = get_label(NULL /* Cannot fail, token is T_IDENTIFIER. */);
8970         statement->label.label = label;
8971
8972         PUSH_PARENT(statement);
8973
8974         /* if statement is already set then the label is defined twice,
8975          * otherwise it was just mentioned in a goto/local label declaration so far
8976          */
8977         source_position_t const* const pos = &statement->base.source_position;
8978         if (label->statement != NULL) {
8979                 errorf(pos, "duplicate '%N' (declared %P)", (entity_t const*)label, &label->base.source_position);
8980         } else {
8981                 label->base.source_position = *pos;
8982                 label->statement            = statement;
8983         }
8984
8985         eat(':');
8986
8987         if (token.kind == T___attribute__ && !(c_mode & _CXX)) {
8988                 parse_attributes(NULL); // TODO process attributes
8989         }
8990
8991         statement->label.statement = parse_label_inner_statement(statement, "label");
8992
8993         /* remember the labels in a list for later checking */
8994         *label_anchor = &statement->label;
8995         label_anchor  = &statement->label.next;
8996
8997         POP_PARENT();
8998         return statement;
8999 }
9000
9001 static statement_t *parse_inner_statement(void)
9002 {
9003         statement_t *const stmt = parse_statement();
9004         /* ISO/IEC  9899:1999(E) §6.8:1/6.8.2:1  Declarations are no statements */
9005         /* ISO/IEC 14882:1998(E) §6:1/§6.7       Declarations are statements */
9006         if (stmt->kind == STATEMENT_DECLARATION && !(c_mode & _CXX)) {
9007                 errorf(&stmt->base.source_position, "declaration as inner statement, use {}");
9008         }
9009         return stmt;
9010 }
9011
9012 /**
9013  * Parse an expression in parentheses and mark its variables as read.
9014  */
9015 static expression_t *parse_condition(void)
9016 {
9017         add_anchor_token(')');
9018         expect('(');
9019         expression_t *const expr = parse_expression();
9020         mark_vars_read(expr, NULL);
9021         rem_anchor_token(')');
9022         expect(')');
9023         return expr;
9024 }
9025
9026 /**
9027  * Parse an if statement.
9028  */
9029 static statement_t *parse_if(void)
9030 {
9031         statement_t *statement = allocate_statement_zero(STATEMENT_IF);
9032
9033         eat(T_if);
9034
9035         PUSH_PARENT(statement);
9036         PUSH_SCOPE_STATEMENT(&statement->ifs.scope);
9037
9038         add_anchor_token(T_else);
9039
9040         expression_t *const expr = parse_condition();
9041         statement->ifs.condition = expr;
9042         /* §6.8.4.1:1  The controlling expression of an if statement shall have
9043          *             scalar type. */
9044         semantic_condition(expr, "condition of 'if'-statment");
9045
9046         statement_t *const true_stmt = parse_inner_statement();
9047         statement->ifs.true_statement = true_stmt;
9048         rem_anchor_token(T_else);
9049
9050         if (true_stmt->kind == STATEMENT_EMPTY) {
9051                 warningf(WARN_EMPTY_BODY, HERE,
9052                         "suggest braces around empty body in an ‘if’ statement");
9053         }
9054
9055         if (next_if(T_else)) {
9056                 statement->ifs.false_statement = parse_inner_statement();
9057
9058                 if (statement->ifs.false_statement->kind == STATEMENT_EMPTY) {
9059                         warningf(WARN_EMPTY_BODY, HERE,
9060                                         "suggest braces around empty body in an ‘if’ statement");
9061                 }
9062         } else if (true_stmt->kind == STATEMENT_IF &&
9063                         true_stmt->ifs.false_statement != NULL) {
9064                 source_position_t const *const pos = &true_stmt->base.source_position;
9065                 warningf(WARN_PARENTHESES, pos, "suggest explicit braces to avoid ambiguous 'else'");
9066         }
9067
9068         POP_SCOPE();
9069         POP_PARENT();
9070         return statement;
9071 }
9072
9073 /**
9074  * Check that all enums are handled in a switch.
9075  *
9076  * @param statement  the switch statement to check
9077  */
9078 static void check_enum_cases(const switch_statement_t *statement)
9079 {
9080         if (!is_warn_on(WARN_SWITCH_ENUM))
9081                 return;
9082         const type_t *type = skip_typeref(statement->expression->base.type);
9083         if (! is_type_enum(type))
9084                 return;
9085         const enum_type_t *enumt = &type->enumt;
9086
9087         /* if we have a default, no warnings */
9088         if (statement->default_label != NULL)
9089                 return;
9090
9091         /* FIXME: calculation of value should be done while parsing */
9092         /* TODO: quadratic algorithm here. Change to an n log n one */
9093         long            last_value = -1;
9094         const entity_t *entry      = enumt->enume->base.next;
9095         for (; entry != NULL && entry->kind == ENTITY_ENUM_VALUE;
9096              entry = entry->base.next) {
9097                 const expression_t *expression = entry->enum_value.value;
9098                 long                value      = expression != NULL ? fold_constant_to_int(expression) : last_value + 1;
9099                 bool                found      = false;
9100                 for (const case_label_statement_t *l = statement->first_case; l != NULL; l = l->next) {
9101                         if (l->expression == NULL)
9102                                 continue;
9103                         if (l->first_case <= value && value <= l->last_case) {
9104                                 found = true;
9105                                 break;
9106                         }
9107                 }
9108                 if (!found) {
9109                         source_position_t const *const pos = &statement->base.source_position;
9110                         warningf(WARN_SWITCH_ENUM, pos, "'%N' not handled in switch", entry);
9111                 }
9112                 last_value = value;
9113         }
9114 }
9115
9116 /**
9117  * Parse a switch statement.
9118  */
9119 static statement_t *parse_switch(void)
9120 {
9121         statement_t *statement = allocate_statement_zero(STATEMENT_SWITCH);
9122
9123         eat(T_switch);
9124
9125         PUSH_PARENT(statement);
9126         PUSH_SCOPE_STATEMENT(&statement->switchs.scope);
9127
9128         expression_t *const expr = parse_condition();
9129         type_t       *      type = skip_typeref(expr->base.type);
9130         if (is_type_integer(type)) {
9131                 type = promote_integer(type);
9132                 if (get_akind_rank(get_akind(type)) >= get_akind_rank(ATOMIC_TYPE_LONG)) {
9133                         warningf(WARN_TRADITIONAL, &expr->base.source_position, "'%T' switch expression not converted to '%T' in ISO C", type, type_int);
9134                 }
9135         } else if (is_type_valid(type)) {
9136                 errorf(&expr->base.source_position,
9137                        "switch quantity is not an integer, but '%T'", type);
9138                 type = type_error_type;
9139         }
9140         statement->switchs.expression = create_implicit_cast(expr, type);
9141
9142         switch_statement_t *rem = current_switch;
9143         current_switch          = &statement->switchs;
9144         statement->switchs.body = parse_inner_statement();
9145         current_switch          = rem;
9146
9147         if (statement->switchs.default_label == NULL) {
9148                 warningf(WARN_SWITCH_DEFAULT, &statement->base.source_position, "switch has no default case");
9149         }
9150         check_enum_cases(&statement->switchs);
9151
9152         POP_SCOPE();
9153         POP_PARENT();
9154         return statement;
9155 }
9156
9157 static statement_t *parse_loop_body(statement_t *const loop)
9158 {
9159         statement_t *const rem = current_loop;
9160         current_loop = loop;
9161
9162         statement_t *const body = parse_inner_statement();
9163
9164         current_loop = rem;
9165         return body;
9166 }
9167
9168 /**
9169  * Parse a while statement.
9170  */
9171 static statement_t *parse_while(void)
9172 {
9173         statement_t *statement = allocate_statement_zero(STATEMENT_WHILE);
9174
9175         eat(T_while);
9176
9177         PUSH_PARENT(statement);
9178         PUSH_SCOPE_STATEMENT(&statement->whiles.scope);
9179
9180         expression_t *const cond = parse_condition();
9181         statement->whiles.condition = cond;
9182         /* §6.8.5:2    The controlling expression of an iteration statement shall
9183          *             have scalar type. */
9184         semantic_condition(cond, "condition of 'while'-statement");
9185
9186         statement->whiles.body = parse_loop_body(statement);
9187
9188         POP_SCOPE();
9189         POP_PARENT();
9190         return statement;
9191 }
9192
9193 /**
9194  * Parse a do statement.
9195  */
9196 static statement_t *parse_do(void)
9197 {
9198         statement_t *statement = allocate_statement_zero(STATEMENT_DO_WHILE);
9199
9200         eat(T_do);
9201
9202         PUSH_PARENT(statement);
9203         PUSH_SCOPE_STATEMENT(&statement->do_while.scope);
9204
9205         add_anchor_token(T_while);
9206         statement->do_while.body = parse_loop_body(statement);
9207         rem_anchor_token(T_while);
9208
9209         expect(T_while);
9210         expression_t *const cond = parse_condition();
9211         statement->do_while.condition = cond;
9212         /* §6.8.5:2    The controlling expression of an iteration statement shall
9213          *             have scalar type. */
9214         semantic_condition(cond, "condition of 'do-while'-statement");
9215         expect(';');
9216
9217         POP_SCOPE();
9218         POP_PARENT();
9219         return statement;
9220 }
9221
9222 /**
9223  * Parse a for statement.
9224  */
9225 static statement_t *parse_for(void)
9226 {
9227         statement_t *statement = allocate_statement_zero(STATEMENT_FOR);
9228
9229         eat(T_for);
9230
9231         PUSH_PARENT(statement);
9232         PUSH_SCOPE_STATEMENT(&statement->fors.scope);
9233
9234         add_anchor_token(')');
9235         expect('(');
9236
9237         PUSH_EXTENSION();
9238
9239         if (next_if(';')) {
9240         } else if (is_declaration_specifier(&token)) {
9241                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9242         } else {
9243                 add_anchor_token(';');
9244                 expression_t *const init = parse_expression();
9245                 statement->fors.initialisation = init;
9246                 mark_vars_read(init, ENT_ANY);
9247                 if (!expression_has_effect(init)) {
9248                         warningf(WARN_UNUSED_VALUE, &init->base.source_position, "initialisation of 'for'-statement has no effect");
9249                 }
9250                 rem_anchor_token(';');
9251                 expect(';');
9252         }
9253
9254         POP_EXTENSION();
9255
9256         if (token.kind != ';') {
9257                 add_anchor_token(';');
9258                 expression_t *const cond = parse_expression();
9259                 statement->fors.condition = cond;
9260                 /* §6.8.5:2    The controlling expression of an iteration statement
9261                  *             shall have scalar type. */
9262                 semantic_condition(cond, "condition of 'for'-statement");
9263                 mark_vars_read(cond, NULL);
9264                 rem_anchor_token(';');
9265         }
9266         expect(';');
9267         if (token.kind != ')') {
9268                 expression_t *const step = parse_expression();
9269                 statement->fors.step = step;
9270                 mark_vars_read(step, ENT_ANY);
9271                 if (!expression_has_effect(step)) {
9272                         warningf(WARN_UNUSED_VALUE, &step->base.source_position, "step of 'for'-statement has no effect");
9273                 }
9274         }
9275         rem_anchor_token(')');
9276         expect(')');
9277         statement->fors.body = parse_loop_body(statement);
9278
9279         POP_SCOPE();
9280         POP_PARENT();
9281         return statement;
9282 }
9283
9284 /**
9285  * Parse a goto statement.
9286  */
9287 static statement_t *parse_goto(void)
9288 {
9289         statement_t *statement;
9290         if (GNU_MODE && look_ahead(1)->kind == '*') {
9291                 statement = allocate_statement_zero(STATEMENT_COMPUTED_GOTO);
9292                 eat(T_goto);
9293                 eat('*');
9294
9295                 expression_t *expression = parse_expression();
9296                 mark_vars_read(expression, NULL);
9297
9298                 /* Argh: although documentation says the expression must be of type void*,
9299                  * gcc accepts anything that can be casted into void* without error */
9300                 type_t *type = expression->base.type;
9301
9302                 if (type != type_error_type) {
9303                         if (!is_type_pointer(type) && !is_type_integer(type)) {
9304                                 errorf(&expression->base.source_position,
9305                                         "cannot convert to a pointer type");
9306                         } else if (type != type_void_ptr) {
9307                                 warningf(WARN_OTHER, &expression->base.source_position, "type of computed goto expression should be 'void*' not '%T'", type);
9308                         }
9309                         expression = create_implicit_cast(expression, type_void_ptr);
9310                 }
9311
9312                 statement->computed_goto.expression = expression;
9313         } else {
9314                 statement = allocate_statement_zero(STATEMENT_GOTO);
9315                 eat(T_goto);
9316
9317                 label_t *const label = get_label("while parsing goto");
9318                 if (label) {
9319                         label->used            = true;
9320                         statement->gotos.label = label;
9321
9322                         /* remember the goto's in a list for later checking */
9323                         *goto_anchor = &statement->gotos;
9324                         goto_anchor  = &statement->gotos.next;
9325                 } else {
9326                         statement->gotos.label = &allocate_entity_zero(ENTITY_LABEL, NAMESPACE_LABEL, sym_anonymous, &builtin_source_position)->label;
9327                 }
9328         }
9329
9330         expect(';');
9331         return statement;
9332 }
9333
9334 /**
9335  * Parse a continue statement.
9336  */
9337 static statement_t *parse_continue(void)
9338 {
9339         if (current_loop == NULL) {
9340                 errorf(HERE, "continue statement not within loop");
9341         }
9342
9343         statement_t *statement = allocate_statement_zero(STATEMENT_CONTINUE);
9344
9345         eat(T_continue);
9346         expect(';');
9347         return statement;
9348 }
9349
9350 /**
9351  * Parse a break statement.
9352  */
9353 static statement_t *parse_break(void)
9354 {
9355         if (current_switch == NULL && current_loop == NULL) {
9356                 errorf(HERE, "break statement not within loop or switch");
9357         }
9358
9359         statement_t *statement = allocate_statement_zero(STATEMENT_BREAK);
9360
9361         eat(T_break);
9362         expect(';');
9363         return statement;
9364 }
9365
9366 /**
9367  * Parse a __leave statement.
9368  */
9369 static statement_t *parse_leave_statement(void)
9370 {
9371         if (current_try == NULL) {
9372                 errorf(HERE, "__leave statement not within __try");
9373         }
9374
9375         statement_t *statement = allocate_statement_zero(STATEMENT_LEAVE);
9376
9377         eat(T___leave);
9378         expect(';');
9379         return statement;
9380 }
9381
9382 /**
9383  * Check if a given entity represents a local variable.
9384  */
9385 static bool is_local_variable(const entity_t *entity)
9386 {
9387         if (entity->kind != ENTITY_VARIABLE)
9388                 return false;
9389
9390         switch ((storage_class_tag_t) entity->declaration.storage_class) {
9391         case STORAGE_CLASS_AUTO:
9392         case STORAGE_CLASS_REGISTER: {
9393                 const type_t *type = skip_typeref(entity->declaration.type);
9394                 if (is_type_function(type)) {
9395                         return false;
9396                 } else {
9397                         return true;
9398                 }
9399         }
9400         default:
9401                 return false;
9402         }
9403 }
9404
9405 /**
9406  * Check if a given expression represents a local variable.
9407  */
9408 static bool expression_is_local_variable(const expression_t *expression)
9409 {
9410         if (expression->base.kind != EXPR_REFERENCE) {
9411                 return false;
9412         }
9413         const entity_t *entity = expression->reference.entity;
9414         return is_local_variable(entity);
9415 }
9416
9417 static void err_or_warn(source_position_t const *const pos, char const *const msg)
9418 {
9419         if (c_mode & _CXX || strict_mode) {
9420                 errorf(pos, msg);
9421         } else {
9422                 warningf(WARN_OTHER, pos, msg);
9423         }
9424 }
9425
9426 /**
9427  * Parse a return statement.
9428  */
9429 static statement_t *parse_return(void)
9430 {
9431         statement_t *statement = allocate_statement_zero(STATEMENT_RETURN);
9432         eat(T_return);
9433
9434         expression_t *return_value = NULL;
9435         if (token.kind != ';') {
9436                 return_value = parse_expression();
9437                 mark_vars_read(return_value, NULL);
9438         }
9439
9440         const type_t *const func_type = skip_typeref(current_function->base.type);
9441         assert(is_type_function(func_type));
9442         type_t *const return_type = skip_typeref(func_type->function.return_type);
9443
9444         source_position_t const *const pos = &statement->base.source_position;
9445         if (return_value != NULL) {
9446                 type_t *return_value_type = skip_typeref(return_value->base.type);
9447
9448                 if (is_type_void(return_type)) {
9449                         if (!is_type_void(return_value_type)) {
9450                                 /* ISO/IEC 14882:1998(E) §6.6.3:2 */
9451                                 /* Only warn in C mode, because GCC does the same */
9452                                 err_or_warn(pos, "'return' with a value, in function returning 'void'");
9453                         } else if (!(c_mode & _CXX)) { /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9454                                 /* Only warn in C mode, because GCC does the same */
9455                                 err_or_warn(pos, "'return' with expression in function returning 'void'");
9456                         }
9457                 } else {
9458                         assign_error_t error = semantic_assign(return_type, return_value);
9459                         report_assign_error(error, return_type, return_value, "'return'",
9460                                             pos);
9461                 }
9462                 return_value = create_implicit_cast(return_value, return_type);
9463                 /* check for returning address of a local var */
9464                 if (return_value != NULL && return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
9465                         const expression_t *expression = return_value->unary.value;
9466                         if (expression_is_local_variable(expression)) {
9467                                 warningf(WARN_OTHER, pos, "function returns address of local variable");
9468                         }
9469                 }
9470         } else if (!is_type_void(return_type)) {
9471                 /* ISO/IEC 14882:1998(E) §6.6.3:3 */
9472                 err_or_warn(pos, "'return' without value, in function returning non-void");
9473         }
9474         statement->returns.value = return_value;
9475
9476         expect(';');
9477         return statement;
9478 }
9479
9480 /**
9481  * Parse a declaration statement.
9482  */
9483 static statement_t *parse_declaration_statement(void)
9484 {
9485         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9486
9487         entity_t *before = current_scope->last_entity;
9488         if (GNU_MODE) {
9489                 parse_external_declaration();
9490         } else {
9491                 parse_declaration(record_entity, DECL_FLAGS_NONE);
9492         }
9493
9494         declaration_statement_t *const decl  = &statement->declaration;
9495         entity_t                *const begin =
9496                 before != NULL ? before->base.next : current_scope->entities;
9497         decl->declarations_begin = begin;
9498         decl->declarations_end   = begin != NULL ? current_scope->last_entity : NULL;
9499
9500         return statement;
9501 }
9502
9503 /**
9504  * Parse an expression statement, ie. expr ';'.
9505  */
9506 static statement_t *parse_expression_statement(void)
9507 {
9508         statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
9509
9510         expression_t *const expr         = parse_expression();
9511         statement->expression.expression = expr;
9512         mark_vars_read(expr, ENT_ANY);
9513
9514         expect(';');
9515         return statement;
9516 }
9517
9518 /**
9519  * Parse a microsoft __try { } __finally { } or
9520  * __try{ } __except() { }
9521  */
9522 static statement_t *parse_ms_try_statment(void)
9523 {
9524         statement_t *statement = allocate_statement_zero(STATEMENT_MS_TRY);
9525         eat(T___try);
9526
9527         PUSH_PARENT(statement);
9528
9529         ms_try_statement_t *rem = current_try;
9530         current_try = &statement->ms_try;
9531         statement->ms_try.try_statement = parse_compound_statement(false);
9532         current_try = rem;
9533
9534         POP_PARENT();
9535
9536         if (next_if(T___except)) {
9537                 expression_t *const expr = parse_condition();
9538                 type_t       *      type = skip_typeref(expr->base.type);
9539                 if (is_type_integer(type)) {
9540                         type = promote_integer(type);
9541                 } else if (is_type_valid(type)) {
9542                         errorf(&expr->base.source_position,
9543                                "__expect expression is not an integer, but '%T'", type);
9544                         type = type_error_type;
9545                 }
9546                 statement->ms_try.except_expression = create_implicit_cast(expr, type);
9547         } else if (!next_if(T__finally)) {
9548                 parse_error_expected("while parsing __try statement", T___except, T___finally, NULL);
9549         }
9550         statement->ms_try.final_statement = parse_compound_statement(false);
9551         return statement;
9552 }
9553
9554 static statement_t *parse_empty_statement(void)
9555 {
9556         warningf(WARN_EMPTY_STATEMENT, HERE, "statement is empty");
9557         statement_t *const statement = create_empty_statement();
9558         eat(';');
9559         return statement;
9560 }
9561
9562 static statement_t *parse_local_label_declaration(void)
9563 {
9564         statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
9565
9566         eat(T___label__);
9567
9568         entity_t *begin   = NULL;
9569         entity_t *end     = NULL;
9570         entity_t **anchor = &begin;
9571         add_anchor_token(';');
9572         add_anchor_token(',');
9573         do {
9574                 source_position_t pos;
9575                 symbol_t *const symbol = expect_identifier("while parsing local label declaration", &pos);
9576                 if (symbol) {
9577                         entity_t *entity = get_entity(symbol, NAMESPACE_LABEL);
9578                         if (entity != NULL && entity->base.parent_scope == current_scope) {
9579                                 source_position_t const *const ppos = &entity->base.source_position;
9580                                 errorf(&pos, "multiple definitions of '%N' (previous definition %P)", entity, ppos);
9581                         } else {
9582                                 entity = allocate_entity_zero(ENTITY_LOCAL_LABEL, NAMESPACE_LABEL, symbol, &pos);
9583                                 entity->base.parent_scope = current_scope;
9584
9585                                 *anchor = entity;
9586                                 anchor  = &entity->base.next;
9587                                 end     = entity;
9588
9589                                 environment_push(entity);
9590                         }
9591                 }
9592         } while (next_if(','));
9593         rem_anchor_token(',');
9594         rem_anchor_token(';');
9595         expect(';');
9596         statement->declaration.declarations_begin = begin;
9597         statement->declaration.declarations_end   = end;
9598         return statement;
9599 }
9600
9601 static void parse_namespace_definition(void)
9602 {
9603         eat(T_namespace);
9604
9605         entity_t *entity = NULL;
9606         symbol_t *symbol = NULL;
9607
9608         if (token.kind == T_IDENTIFIER) {
9609                 symbol = token.base.symbol;
9610                 entity = get_entity(symbol, NAMESPACE_NORMAL);
9611                 if (entity && entity->kind != ENTITY_NAMESPACE) {
9612                         entity = NULL;
9613                         if (entity->base.parent_scope == current_scope && is_entity_valid(entity)) {
9614                                 error_redefined_as_different_kind(HERE, entity, ENTITY_NAMESPACE);
9615                         }
9616                 }
9617                 eat(T_IDENTIFIER);
9618         }
9619
9620         if (entity == NULL) {
9621                 entity = allocate_entity_zero(ENTITY_NAMESPACE, NAMESPACE_NORMAL, symbol, HERE);
9622                 entity->base.parent_scope = current_scope;
9623         }
9624
9625         if (token.kind == '=') {
9626                 /* TODO: parse namespace alias */
9627                 panic("namespace alias definition not supported yet");
9628         }
9629
9630         environment_push(entity);
9631         append_entity(current_scope, entity);
9632
9633         PUSH_SCOPE(&entity->namespacee.members);
9634         PUSH_CURRENT_ENTITY(entity);
9635
9636         add_anchor_token('}');
9637         expect('{');
9638         parse_externals();
9639         rem_anchor_token('}');
9640         expect('}');
9641
9642         POP_CURRENT_ENTITY();
9643         POP_SCOPE();
9644 }
9645
9646 /**
9647  * Parse a statement.
9648  * There's also parse_statement() which additionally checks for
9649  * "statement has no effect" warnings
9650  */
9651 static statement_t *intern_parse_statement(void)
9652 {
9653         /* declaration or statement */
9654         statement_t *statement;
9655         switch (token.kind) {
9656         case T_IDENTIFIER: {
9657                 token_kind_t la1_type = (token_kind_t)look_ahead(1)->kind;
9658                 if (la1_type == ':') {
9659                         statement = parse_label_statement();
9660                 } else if (is_typedef_symbol(token.base.symbol)) {
9661                         statement = parse_declaration_statement();
9662                 } else {
9663                         /* it's an identifier, the grammar says this must be an
9664                          * expression statement. However it is common that users mistype
9665                          * declaration types, so we guess a bit here to improve robustness
9666                          * for incorrect programs */
9667                         switch (la1_type) {
9668                         case '&':
9669                         case '*':
9670                                 if (get_entity(token.base.symbol, NAMESPACE_NORMAL) != NULL) {
9671                         default:
9672                                         statement = parse_expression_statement();
9673                                 } else {
9674                         DECLARATION_START
9675                         case T_IDENTIFIER:
9676                                         statement = parse_declaration_statement();
9677                                 }
9678                                 break;
9679                         }
9680                 }
9681                 break;
9682         }
9683
9684         case T___extension__: {
9685                 /* This can be a prefix to a declaration or an expression statement.
9686                  * We simply eat it now and parse the rest with tail recursion. */
9687                 PUSH_EXTENSION();
9688                 statement = intern_parse_statement();
9689                 POP_EXTENSION();
9690                 break;
9691         }
9692
9693         DECLARATION_START
9694                 statement = parse_declaration_statement();
9695                 break;
9696
9697         case T___label__:
9698                 statement = parse_local_label_declaration();
9699                 break;
9700
9701         case ';':         statement = parse_empty_statement();         break;
9702         case '{':         statement = parse_compound_statement(false); break;
9703         case T___leave:   statement = parse_leave_statement();         break;
9704         case T___try:     statement = parse_ms_try_statment();         break;
9705         case T_asm:       statement = parse_asm_statement();           break;
9706         case T_break:     statement = parse_break();                   break;
9707         case T_case:      statement = parse_case_statement();          break;
9708         case T_continue:  statement = parse_continue();                break;
9709         case T_default:   statement = parse_default_statement();       break;
9710         case T_do:        statement = parse_do();                      break;
9711         case T_for:       statement = parse_for();                     break;
9712         case T_goto:      statement = parse_goto();                    break;
9713         case T_if:        statement = parse_if();                      break;
9714         case T_return:    statement = parse_return();                  break;
9715         case T_switch:    statement = parse_switch();                  break;
9716         case T_while:     statement = parse_while();                   break;
9717
9718         EXPRESSION_START
9719                 statement = parse_expression_statement();
9720                 break;
9721
9722         default:
9723                 errorf(HERE, "unexpected token %K while parsing statement", &token);
9724                 statement = create_error_statement();
9725                 eat_until_anchor();
9726                 break;
9727         }
9728
9729         return statement;
9730 }
9731
9732 /**
9733  * parse a statement and emits "statement has no effect" warning if needed
9734  * (This is really a wrapper around intern_parse_statement with check for 1
9735  *  single warning. It is needed, because for statement expressions we have
9736  *  to avoid the warning on the last statement)
9737  */
9738 static statement_t *parse_statement(void)
9739 {
9740         statement_t *statement = intern_parse_statement();
9741
9742         if (statement->kind == STATEMENT_EXPRESSION) {
9743                 expression_t *expression = statement->expression.expression;
9744                 if (!expression_has_effect(expression)) {
9745                         warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9746                 }
9747         }
9748
9749         return statement;
9750 }
9751
9752 /**
9753  * Parse a compound statement.
9754  */
9755 static statement_t *parse_compound_statement(bool inside_expression_statement)
9756 {
9757         statement_t *statement = allocate_statement_zero(STATEMENT_COMPOUND);
9758
9759         PUSH_PARENT(statement);
9760         PUSH_SCOPE(&statement->compound.scope);
9761
9762         eat('{');
9763         add_anchor_token('}');
9764         /* tokens, which can start a statement */
9765         /* TODO MS, __builtin_FOO */
9766         add_anchor_token('!');
9767         add_anchor_token('&');
9768         add_anchor_token('(');
9769         add_anchor_token('*');
9770         add_anchor_token('+');
9771         add_anchor_token('-');
9772         add_anchor_token(';');
9773         add_anchor_token('{');
9774         add_anchor_token('~');
9775         add_anchor_token(T_CHARACTER_CONSTANT);
9776         add_anchor_token(T_COLONCOLON);
9777         add_anchor_token(T_FLOATINGPOINT);
9778         add_anchor_token(T_IDENTIFIER);
9779         add_anchor_token(T_INTEGER);
9780         add_anchor_token(T_MINUSMINUS);
9781         add_anchor_token(T_PLUSPLUS);
9782         add_anchor_token(T_STRING_LITERAL);
9783         add_anchor_token(T__Bool);
9784         add_anchor_token(T__Complex);
9785         add_anchor_token(T__Imaginary);
9786         add_anchor_token(T___PRETTY_FUNCTION__);
9787         add_anchor_token(T___alignof__);
9788         add_anchor_token(T___attribute__);
9789         add_anchor_token(T___builtin_va_start);
9790         add_anchor_token(T___extension__);
9791         add_anchor_token(T___func__);
9792         add_anchor_token(T___imag__);
9793         add_anchor_token(T___label__);
9794         add_anchor_token(T___real__);
9795         add_anchor_token(T___thread);
9796         add_anchor_token(T_asm);
9797         add_anchor_token(T_auto);
9798         add_anchor_token(T_bool);
9799         add_anchor_token(T_break);
9800         add_anchor_token(T_case);
9801         add_anchor_token(T_char);
9802         add_anchor_token(T_class);
9803         add_anchor_token(T_const);
9804         add_anchor_token(T_const_cast);
9805         add_anchor_token(T_continue);
9806         add_anchor_token(T_default);
9807         add_anchor_token(T_delete);
9808         add_anchor_token(T_double);
9809         add_anchor_token(T_do);
9810         add_anchor_token(T_dynamic_cast);
9811         add_anchor_token(T_enum);
9812         add_anchor_token(T_extern);
9813         add_anchor_token(T_false);
9814         add_anchor_token(T_float);
9815         add_anchor_token(T_for);
9816         add_anchor_token(T_goto);
9817         add_anchor_token(T_if);
9818         add_anchor_token(T_inline);
9819         add_anchor_token(T_int);
9820         add_anchor_token(T_long);
9821         add_anchor_token(T_new);
9822         add_anchor_token(T_operator);
9823         add_anchor_token(T_register);
9824         add_anchor_token(T_reinterpret_cast);
9825         add_anchor_token(T_restrict);
9826         add_anchor_token(T_return);
9827         add_anchor_token(T_short);
9828         add_anchor_token(T_signed);
9829         add_anchor_token(T_sizeof);
9830         add_anchor_token(T_static);
9831         add_anchor_token(T_static_cast);
9832         add_anchor_token(T_struct);
9833         add_anchor_token(T_switch);
9834         add_anchor_token(T_template);
9835         add_anchor_token(T_this);
9836         add_anchor_token(T_throw);
9837         add_anchor_token(T_true);
9838         add_anchor_token(T_try);
9839         add_anchor_token(T_typedef);
9840         add_anchor_token(T_typeid);
9841         add_anchor_token(T_typename);
9842         add_anchor_token(T_typeof);
9843         add_anchor_token(T_union);
9844         add_anchor_token(T_unsigned);
9845         add_anchor_token(T_using);
9846         add_anchor_token(T_void);
9847         add_anchor_token(T_volatile);
9848         add_anchor_token(T_wchar_t);
9849         add_anchor_token(T_while);
9850
9851         statement_t **anchor            = &statement->compound.statements;
9852         bool          only_decls_so_far = true;
9853         while (token.kind != '}' && token.kind != T_EOF) {
9854                 statement_t *sub_statement = intern_parse_statement();
9855                 if (sub_statement->kind == STATEMENT_ERROR) {
9856                         break;
9857                 }
9858
9859                 if (sub_statement->kind != STATEMENT_DECLARATION) {
9860                         only_decls_so_far = false;
9861                 } else if (!only_decls_so_far) {
9862                         source_position_t const *const pos = &sub_statement->base.source_position;
9863                         warningf(WARN_DECLARATION_AFTER_STATEMENT, pos, "ISO C90 forbids mixed declarations and code");
9864                 }
9865
9866                 *anchor = sub_statement;
9867                 anchor  = &sub_statement->base.next;
9868         }
9869         expect('}');
9870
9871         /* look over all statements again to produce no effect warnings */
9872         if (is_warn_on(WARN_UNUSED_VALUE)) {
9873                 statement_t *sub_statement = statement->compound.statements;
9874                 for (; sub_statement != NULL; sub_statement = sub_statement->base.next) {
9875                         if (sub_statement->kind != STATEMENT_EXPRESSION)
9876                                 continue;
9877                         /* don't emit a warning for the last expression in an expression
9878                          * statement as it has always an effect */
9879                         if (inside_expression_statement && sub_statement->base.next == NULL)
9880                                 continue;
9881
9882                         expression_t *expression = sub_statement->expression.expression;
9883                         if (!expression_has_effect(expression)) {
9884                                 warningf(WARN_UNUSED_VALUE, &expression->base.source_position, "statement has no effect");
9885                         }
9886                 }
9887         }
9888
9889         rem_anchor_token(T_while);
9890         rem_anchor_token(T_wchar_t);
9891         rem_anchor_token(T_volatile);
9892         rem_anchor_token(T_void);
9893         rem_anchor_token(T_using);
9894         rem_anchor_token(T_unsigned);
9895         rem_anchor_token(T_union);
9896         rem_anchor_token(T_typeof);
9897         rem_anchor_token(T_typename);
9898         rem_anchor_token(T_typeid);
9899         rem_anchor_token(T_typedef);
9900         rem_anchor_token(T_try);
9901         rem_anchor_token(T_true);
9902         rem_anchor_token(T_throw);
9903         rem_anchor_token(T_this);
9904         rem_anchor_token(T_template);
9905         rem_anchor_token(T_switch);
9906         rem_anchor_token(T_struct);
9907         rem_anchor_token(T_static_cast);
9908         rem_anchor_token(T_static);
9909         rem_anchor_token(T_sizeof);
9910         rem_anchor_token(T_signed);
9911         rem_anchor_token(T_short);
9912         rem_anchor_token(T_return);
9913         rem_anchor_token(T_restrict);
9914         rem_anchor_token(T_reinterpret_cast);
9915         rem_anchor_token(T_register);
9916         rem_anchor_token(T_operator);
9917         rem_anchor_token(T_new);
9918         rem_anchor_token(T_long);
9919         rem_anchor_token(T_int);
9920         rem_anchor_token(T_inline);
9921         rem_anchor_token(T_if);
9922         rem_anchor_token(T_goto);
9923         rem_anchor_token(T_for);
9924         rem_anchor_token(T_float);
9925         rem_anchor_token(T_false);
9926         rem_anchor_token(T_extern);
9927         rem_anchor_token(T_enum);
9928         rem_anchor_token(T_dynamic_cast);
9929         rem_anchor_token(T_do);
9930         rem_anchor_token(T_double);
9931         rem_anchor_token(T_delete);
9932         rem_anchor_token(T_default);
9933         rem_anchor_token(T_continue);
9934         rem_anchor_token(T_const_cast);
9935         rem_anchor_token(T_const);
9936         rem_anchor_token(T_class);
9937         rem_anchor_token(T_char);
9938         rem_anchor_token(T_case);
9939         rem_anchor_token(T_break);
9940         rem_anchor_token(T_bool);
9941         rem_anchor_token(T_auto);
9942         rem_anchor_token(T_asm);
9943         rem_anchor_token(T___thread);
9944         rem_anchor_token(T___real__);
9945         rem_anchor_token(T___label__);
9946         rem_anchor_token(T___imag__);
9947         rem_anchor_token(T___func__);
9948         rem_anchor_token(T___extension__);
9949         rem_anchor_token(T___builtin_va_start);
9950         rem_anchor_token(T___attribute__);
9951         rem_anchor_token(T___alignof__);
9952         rem_anchor_token(T___PRETTY_FUNCTION__);
9953         rem_anchor_token(T__Imaginary);
9954         rem_anchor_token(T__Complex);
9955         rem_anchor_token(T__Bool);
9956         rem_anchor_token(T_STRING_LITERAL);
9957         rem_anchor_token(T_PLUSPLUS);
9958         rem_anchor_token(T_MINUSMINUS);
9959         rem_anchor_token(T_INTEGER);
9960         rem_anchor_token(T_IDENTIFIER);
9961         rem_anchor_token(T_FLOATINGPOINT);
9962         rem_anchor_token(T_COLONCOLON);
9963         rem_anchor_token(T_CHARACTER_CONSTANT);
9964         rem_anchor_token('~');
9965         rem_anchor_token('{');
9966         rem_anchor_token(';');
9967         rem_anchor_token('-');
9968         rem_anchor_token('+');
9969         rem_anchor_token('*');
9970         rem_anchor_token('(');
9971         rem_anchor_token('&');
9972         rem_anchor_token('!');
9973         rem_anchor_token('}');
9974
9975         POP_SCOPE();
9976         POP_PARENT();
9977         return statement;
9978 }
9979
9980 /**
9981  * Check for unused global static functions and variables
9982  */
9983 static void check_unused_globals(void)
9984 {
9985         if (!is_warn_on(WARN_UNUSED_FUNCTION) && !is_warn_on(WARN_UNUSED_VARIABLE))
9986                 return;
9987
9988         for (const entity_t *entity = file_scope->entities; entity != NULL;
9989              entity = entity->base.next) {
9990                 if (!is_declaration(entity))
9991                         continue;
9992
9993                 const declaration_t *declaration = &entity->declaration;
9994                 if (declaration->used                  ||
9995                     declaration->modifiers & DM_UNUSED ||
9996                     declaration->modifiers & DM_USED   ||
9997                     declaration->storage_class != STORAGE_CLASS_STATIC)
9998                         continue;
9999
10000                 warning_t   why;
10001                 char const *s;
10002                 if (entity->kind == ENTITY_FUNCTION) {
10003                         /* inhibit warning for static inline functions */
10004                         if (entity->function.is_inline)
10005                                 continue;
10006
10007                         why = WARN_UNUSED_FUNCTION;
10008                         s   = entity->function.statement != NULL ? "defined" : "declared";
10009                 } else {
10010                         why = WARN_UNUSED_VARIABLE;
10011                         s   = "defined";
10012                 }
10013
10014                 warningf(why, &declaration->base.source_position, "'%#N' %s but not used", entity, s);
10015         }
10016 }
10017
10018 static void parse_global_asm(void)
10019 {
10020         statement_t *statement = allocate_statement_zero(STATEMENT_ASM);
10021
10022         eat(T_asm);
10023         add_anchor_token(';');
10024         add_anchor_token(')');
10025         add_anchor_token(T_STRING_LITERAL);
10026         expect('(');
10027
10028         rem_anchor_token(T_STRING_LITERAL);
10029         statement->asms.asm_text = parse_string_literals("global asm");
10030         statement->base.next     = unit->global_asm;
10031         unit->global_asm         = statement;
10032
10033         rem_anchor_token(')');
10034         expect(')');
10035         rem_anchor_token(';');
10036         expect(';');
10037 }
10038
10039 static void parse_linkage_specification(void)
10040 {
10041         eat(T_extern);
10042
10043         source_position_t const pos     = *HERE;
10044         char const       *const linkage = parse_string_literals(NULL).begin;
10045
10046         linkage_kind_t old_linkage = current_linkage;
10047         linkage_kind_t new_linkage;
10048         if (streq(linkage, "C")) {
10049                 new_linkage = LINKAGE_C;
10050         } else if (streq(linkage, "C++")) {
10051                 new_linkage = LINKAGE_CXX;
10052         } else {
10053                 errorf(&pos, "linkage string \"%s\" not recognized", linkage);
10054                 new_linkage = LINKAGE_C;
10055         }
10056         current_linkage = new_linkage;
10057
10058         if (next_if('{')) {
10059                 parse_externals();
10060                 expect('}');
10061         } else {
10062                 parse_external();
10063         }
10064
10065         assert(current_linkage == new_linkage);
10066         current_linkage = old_linkage;
10067 }
10068
10069 static void parse_external(void)
10070 {
10071         switch (token.kind) {
10072                 case T_extern:
10073                         if (look_ahead(1)->kind == T_STRING_LITERAL) {
10074                                 parse_linkage_specification();
10075                         } else {
10076                 DECLARATION_START_NO_EXTERN
10077                 case T_IDENTIFIER:
10078                 case T___extension__:
10079                 /* tokens below are for implicit int */
10080                 case '&':  /* & x; -> int& x; (and error later, because C++ has no
10081                               implicit int) */
10082                 case '*':  /* * x; -> int* x; */
10083                 case '(':  /* (x); -> int (x); */
10084                                 PUSH_EXTENSION();
10085                                 parse_external_declaration();
10086                                 POP_EXTENSION();
10087                         }
10088                         return;
10089
10090                 case T_asm:
10091                         parse_global_asm();
10092                         return;
10093
10094                 case T_namespace:
10095                         parse_namespace_definition();
10096                         return;
10097
10098                 case ';':
10099                         if (!strict_mode) {
10100                                 warningf(WARN_STRAY_SEMICOLON, HERE, "stray ';' outside of function");
10101                                 eat(';');
10102                                 return;
10103                         }
10104                         /* FALLTHROUGH */
10105
10106                 default:
10107                         errorf(HERE, "stray %K outside of function", &token);
10108                         if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10109                                 eat_until_matching_token(token.kind);
10110                         next_token();
10111                         return;
10112         }
10113 }
10114
10115 static void parse_externals(void)
10116 {
10117         add_anchor_token('}');
10118         add_anchor_token(T_EOF);
10119
10120 #ifndef NDEBUG
10121         /* make a copy of the anchor set, so we can check if it is restored after parsing */
10122         unsigned short token_anchor_copy[T_LAST_TOKEN];
10123         memcpy(token_anchor_copy, token_anchor_set, sizeof(token_anchor_copy));
10124 #endif
10125
10126         while (token.kind != T_EOF && token.kind != '}') {
10127 #ifndef NDEBUG
10128                 for (int i = 0; i < T_LAST_TOKEN; ++i) {
10129                         unsigned short count = token_anchor_set[i] - token_anchor_copy[i];
10130                         if (count != 0) {
10131                                 /* the anchor set and its copy differs */
10132                                 internal_errorf(HERE, "Leaked anchor token %k %d times", i, count);
10133                         }
10134                 }
10135                 if (in_gcc_extension) {
10136                         /* an gcc extension scope was not closed */
10137                         internal_errorf(HERE, "Leaked __extension__");
10138                 }
10139 #endif
10140
10141                 parse_external();
10142         }
10143
10144         rem_anchor_token(T_EOF);
10145         rem_anchor_token('}');
10146 }
10147
10148 /**
10149  * Parse a translation unit.
10150  */
10151 static void parse_translation_unit(void)
10152 {
10153         add_anchor_token(T_EOF);
10154
10155         while (true) {
10156                 parse_externals();
10157
10158                 if (token.kind == T_EOF)
10159                         break;
10160
10161                 errorf(HERE, "stray %K outside of function", &token);
10162                 if (token.kind == '(' || token.kind == '{' || token.kind == '[')
10163                         eat_until_matching_token(token.kind);
10164                 next_token();
10165         }
10166 }
10167
10168 void set_default_visibility(elf_visibility_tag_t visibility)
10169 {
10170         default_visibility = visibility;
10171 }
10172
10173 /**
10174  * Parse the input.
10175  *
10176  * @return  the translation unit or NULL if errors occurred.
10177  */
10178 void start_parsing(void)
10179 {
10180         environment_stack = NEW_ARR_F(stack_entry_t, 0);
10181         label_stack       = NEW_ARR_F(stack_entry_t, 0);
10182         diagnostic_count  = 0;
10183         error_count       = 0;
10184         warning_count     = 0;
10185
10186         print_to_file(stderr);
10187
10188         assert(unit == NULL);
10189         unit = allocate_ast_zero(sizeof(unit[0]));
10190
10191         assert(file_scope == NULL);
10192         file_scope = &unit->scope;
10193
10194         assert(current_scope == NULL);
10195         scope_push(&unit->scope);
10196
10197         create_gnu_builtins();
10198         if (c_mode & _MS)
10199                 create_microsoft_intrinsics();
10200 }
10201
10202 translation_unit_t *finish_parsing(void)
10203 {
10204         assert(current_scope == &unit->scope);
10205         scope_pop(NULL);
10206
10207         assert(file_scope == &unit->scope);
10208         check_unused_globals();
10209         file_scope = NULL;
10210
10211         DEL_ARR_F(environment_stack);
10212         DEL_ARR_F(label_stack);
10213
10214         translation_unit_t *result = unit;
10215         unit = NULL;
10216         return result;
10217 }
10218
10219 /* §6.9.2:2 and §6.9.2:5: At the end of the translation incomplete arrays
10220  * are given length one. */
10221 static void complete_incomplete_arrays(void)
10222 {
10223         size_t n = ARR_LEN(incomplete_arrays);
10224         for (size_t i = 0; i != n; ++i) {
10225                 declaration_t *const decl = incomplete_arrays[i];
10226                 type_t        *const type = skip_typeref(decl->type);
10227
10228                 if (!is_type_incomplete(type))
10229                         continue;
10230
10231                 source_position_t const *const pos = &decl->base.source_position;
10232                 warningf(WARN_OTHER, pos, "array '%#N' assumed to have one element", (entity_t const*)decl);
10233
10234                 type_t *const new_type = duplicate_type(type);
10235                 new_type->array.size_constant     = true;
10236                 new_type->array.has_implicit_size = true;
10237                 new_type->array.size              = 1;
10238
10239                 type_t *const result = identify_new_type(new_type);
10240
10241                 decl->type = result;
10242         }
10243 }
10244
10245 static void prepare_main_collect2(entity_t *const entity)
10246 {
10247         PUSH_SCOPE(&entity->function.statement->compound.scope);
10248
10249         // create call to __main
10250         symbol_t *symbol         = symbol_table_insert("__main");
10251         entity_t *subsubmain_ent
10252                 = create_implicit_function(symbol, &builtin_source_position);
10253
10254         expression_t *ref         = allocate_expression_zero(EXPR_REFERENCE);
10255         type_t       *ftype       = subsubmain_ent->declaration.type;
10256         ref->base.source_position = builtin_source_position;
10257         ref->base.type            = make_pointer_type(ftype, TYPE_QUALIFIER_NONE);
10258         ref->reference.entity     = subsubmain_ent;
10259
10260         expression_t *call = allocate_expression_zero(EXPR_CALL);
10261         call->base.source_position = builtin_source_position;
10262         call->base.type            = type_void;
10263         call->call.function        = ref;
10264
10265         statement_t *expr_statement = allocate_statement_zero(STATEMENT_EXPRESSION);
10266         expr_statement->base.source_position  = builtin_source_position;
10267         expr_statement->expression.expression = call;
10268
10269         statement_t *statement = entity->function.statement;
10270         assert(statement->kind == STATEMENT_COMPOUND);
10271         compound_statement_t *compounds = &statement->compound;
10272
10273         expr_statement->base.next = compounds->statements;
10274         compounds->statements     = expr_statement;
10275
10276         POP_SCOPE();
10277 }
10278
10279 void parse(void)
10280 {
10281         lookahead_bufpos = 0;
10282         for (int i = 0; i < MAX_LOOKAHEAD + 2; ++i) {
10283                 next_token();
10284         }
10285         current_linkage   = c_mode & _CXX ? LINKAGE_CXX : LINKAGE_C;
10286         incomplete_arrays = NEW_ARR_F(declaration_t*, 0);
10287         parse_translation_unit();
10288         complete_incomplete_arrays();
10289         DEL_ARR_F(incomplete_arrays);
10290         incomplete_arrays = NULL;
10291 }
10292
10293 /**
10294  * Initialize the parser.
10295  */
10296 void init_parser(void)
10297 {
10298         sym_anonymous = symbol_table_insert("<anonymous>");
10299
10300         memset(token_anchor_set, 0, sizeof(token_anchor_set));
10301
10302         init_expression_parsers();
10303         obstack_init(&temp_obst);
10304 }
10305
10306 /**
10307  * Terminate the parser.
10308  */
10309 void exit_parser(void)
10310 {
10311         obstack_free(&temp_obst, NULL);
10312 }