symbol.c

   1 /*
   2  * Symbol lookup and handling.
   3  *
   4  * Copyright (C) 2003 Transmeta Corp.
   5  *               2003-2004 Linus Torvalds
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include "lib.h"
  30 #include "allocate.h"
  31 #include "token.h"
  32 #include "parse.h"
  33 #include "symbol.h"
  34 #include "scope.h"
  35 #include "expression.h"
  36
  37 #include "target.h"
  38
  39 /*
  40  * Secondary symbol list for stuff that needs to be output because it
  41  * was used.
  42  */
  43 struct symbol_list *translation_unit_used_list = NULL;
  44
  45 /*
  46  * If the symbol is an inline symbol, add it to the list of symbols to parse
  47  */
  48 void access_symbol(struct symbol *sym)
  49 {
  50         if (sym->ctype.modifiers & MOD_INLINE) {
  51                 if (!(sym->ctype.modifiers & MOD_ACCESSED)) {
  52                         add_symbol(&translation_unit_used_list, sym);
  53                         sym->ctype.modifiers |= MOD_ACCESSED;
  54                 }
  55         }
  56 }
  57
  58 struct symbol *lookup_symbol(struct ident *ident, enum namespace ns)
  59 {
  60         struct symbol *sym;
  61
  62         for (sym = ident->symbols; sym; sym = sym->next_id) {
  63                 if (sym->namespace & ns) {
  64                         sym->used = 1;
  65                         return sym;
  66                 }
  67         }
  68         return NULL;
  69 }
  70
  71 struct context *alloc_context(void)
  72 {
  73         return __alloc_context(0);
  74 }
  75
  76 struct symbol *alloc_symbol(struct position pos, int type)
  77 {
  78         struct symbol *sym = __alloc_symbol(0);
  79         sym->type = type;
  80         sym->pos = pos;
  81         sym->endpos.type = 0;
  82         sym->ctype.attribute = &null_attr;
  83         return sym;
  84 }
  85
  86 struct struct_union_info {
  87         unsigned long max_align;
  88         unsigned long bit_size;
  89         int align_size;
  90         int is_packed;
  91 };
  92
  93 /*
  94  * Unions are fairly easy to lay out ;)
  95  */
  96 static void lay_out_union(struct symbol *sym, struct struct_union_info *info)
  97 {
  98         examine_symbol_type(sym);
  99
 100         // Unnamed bitfields do not affect alignment.
 101         if (sym->ident || !is_bitfield_type(sym)) {
 102                 if (sym->ctype.alignment > info->max_align)
 103                         info->max_align = sym->ctype.alignment;
 104         }
 105
 106         if (sym->bit_size > info->bit_size)
 107                 info->bit_size = sym->bit_size;
 108
 109         sym->offset = 0;
 110 }
 111
 112 static int bitfield_base_size(struct symbol *sym)
 113 {
 114         if (sym->type == SYM_NODE)
 115                 sym = sym->ctype.base_type;
 116         if (sym->type == SYM_BITFIELD)
 117                 sym = sym->ctype.base_type;
 118         return sym->bit_size;
 119 }
 120
 121 /*
 122  * Structures are a bit more interesting to lay out
 123  */
 124 static void lay_out_struct(struct symbol *sym, struct struct_union_info *info)
 125 {
 126         unsigned long bit_size, align_bit_mask;
 127         int base_size;
 128
 129         examine_symbol_type(sym);
 130
 131         // Unnamed bitfields do not affect alignment.
 132         if (sym->ident || !is_bitfield_type(sym)) {
 133                 if (!info->is_packed && sym->ctype.alignment > info->max_align)
 134                         info->max_align = sym->ctype.alignment;
 135         }
 136
 137         bit_size = info->bit_size;
 138         base_size = sym->bit_size;
 139
 140         /*
 141          * Unsized arrays cause us to not align the resulting
 142          * structure size
 143          */
 144         if (base_size < 0) {
 145                 info->align_size = 0;
 146                 base_size = 0;
 147         }
 148
 149         if (info->is_packed)
 150                 align_bit_mask = 0;
 151         else
 152                 align_bit_mask = bytes_to_bits(sym->ctype.alignment) - 1;
 153
 154         /*
 155          * Bitfields have some very special rules..
 156          */
 157         if (is_bitfield_type (sym)) {
 158                 unsigned long bit_offset = bit_size & align_bit_mask;
 159                 int room = bitfield_base_size(sym) - bit_offset;
 160                 // Zero-width fields just fill up the unit.
 161                 int width = base_size ? : (bit_offset ? room : 0);
 162
 163                 if (width > room) {
 164                         bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
 165                         bit_offset = 0;
 166                 }
 167                 sym->offset = bits_to_bytes(bit_size - bit_offset);
 168                 sym->bit_offset = bit_offset;
 169                 sym->ctype.base_type->bit_offset = bit_offset;
 170                 info->bit_size = bit_size + width;
 171                 // warning (sym->pos, "bitfield: offset=%d:%d  size=:%d", sym->offset, sym->bit_offset, width);
 172
 173                 return;
 174         }
 175
 176         /*
 177          * Otherwise, just align it right and add it up..
 178          */
 179         bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
 180         sym->offset = bits_to_bytes(bit_size);
 181
 182         info->bit_size = bit_size + base_size;
 183         // warning (sym->pos, "regular: offset=%d", sym->offset);
 184 }
 185
 186 static struct symbol * examine_struct_union_type(struct symbol *sym, int advance)
 187 {
 188         struct struct_union_info info = {
 189                 .max_align = 1,
 190                 .bit_size = 0,
 191                 .align_size = 1
 192         };
 193         unsigned long bit_size, bit_align;
 194         void (*fn)(struct symbol *, struct struct_union_info *);
 195         struct symbol *member;
 196
 197         info.is_packed = sym->ctype.attribute->is_packed;
 198         fn = advance ? lay_out_struct : lay_out_union;
 199         FOR_EACH_PTR(sym->symbol_list, member) {
 200                 fn(member, &info);
 201         } END_FOR_EACH_PTR(member);
 202
 203         if (!sym->ctype.alignment)
 204                 sym->ctype.alignment = info.max_align;
 205         bit_size = info.bit_size;
 206         if (info.align_size) {
 207                 bit_align = bytes_to_bits(sym->ctype.alignment)-1;
 208                 bit_size = (bit_size + bit_align) & ~bit_align;
 209         }
 210         sym->bit_size = bit_size;
 211         return sym;
 212 }
 213
 214 static struct symbol *examine_base_type(struct symbol *sym)
 215 {
 216         struct symbol *base_type;
 217
 218         /* Check the base type */
 219         base_type = examine_symbol_type(sym->ctype.base_type);
 220         if (!base_type || base_type->type == SYM_PTR)
 221                 return base_type;
 222         sym->ctype.modifiers |= base_type->ctype.modifiers & MOD_PTRINHERIT;
 223
 224         merge_attr(&sym->ctype, &base_type->ctype);
 225
 226         if (base_type->type == SYM_NODE) {
 227                 base_type = base_type->ctype.base_type;
 228                 sym->ctype.base_type = base_type;
 229         }
 230         return base_type;
 231 }
 232
 233 static struct symbol * examine_array_type(struct symbol *sym)
 234 {
 235         struct symbol *base_type = examine_base_type(sym);
 236         unsigned long bit_size = -1, alignment;
 237         struct expression *array_size = sym->array_size;
 238
 239         if (!base_type)
 240                 return sym;
 241
 242         if (array_size) {
 243                 bit_size = array_element_offset(base_type->bit_size,
 244                                                 get_expression_value_silent(array_size));
 245                 if (array_size->type != EXPR_VALUE) {
 246                         if (Wvla)
 247                                 warning(array_size->pos, "Variable length array is used.");
 248                         bit_size = -1;
 249                 }
 250         }
 251         alignment = base_type->ctype.alignment;
 252         if (!sym->ctype.alignment)
 253                 sym->ctype.alignment = alignment;
 254         sym->bit_size = bit_size;
 255         return sym;
 256 }
 257
 258 static struct symbol *examine_bitfield_type(struct symbol *sym)
 259 {
 260         struct symbol *base_type = examine_base_type(sym);
 261         unsigned long bit_size, alignment, modifiers;
 262
 263         if (!base_type)
 264                 return sym;
 265         bit_size = base_type->bit_size;
 266         if (sym->bit_size > bit_size)
 267                 warning(sym->pos, "impossible field-width, %d, for this type",  sym->bit_size);
 268
 269         alignment = base_type->ctype.alignment;
 270         if (!sym->ctype.alignment)
 271                 sym->ctype.alignment = alignment;
 272         modifiers = base_type->ctype.modifiers;
 273
 274         /* Bitfields are unsigned, unless the base type was explicitly signed */
 275         if (!(modifiers & MOD_EXPLICITLY_SIGNED))
 276                 modifiers = (modifiers & ~MOD_SIGNED) | MOD_UNSIGNED;
 277         sym->ctype.modifiers |= modifiers & MOD_SIGNEDNESS;
 278         return sym;
 279 }
 280
 281 /*
 282  * "typeof" will have to merge the types together
 283  */
 284 void merge_type(struct symbol *sym, struct symbol *base_type)
 285 {
 286         sym->ctype.modifiers |= (base_type->ctype.modifiers & ~MOD_STORAGE);
 287         merge_attr(&sym->ctype, &base_type->ctype);
 288         sym->ctype.base_type = base_type->ctype.base_type;
 289         if (sym->ctype.base_type->type == SYM_NODE)
 290                 merge_type(sym, sym->ctype.base_type);
 291 }
 292
 293 static int count_array_initializer(struct symbol *t, struct expression *expr)
 294 {
 295         int nr = 0;
 296         int is_char = 0;
 297
 298         /*
 299          * Arrays of character types are special; they can be initialized by
 300          * string literal _or_ by string literal in braces.  The latter means
 301          * that with T x[] = {<string literal>} number of elements in x depends
 302          * on T - if it's a character type, we get the length of string literal
 303          * (including NUL), otherwise we have one element here.
 304          */
 305         if (t->ctype.base_type == &int_type && t->ctype.modifiers & MOD_CHAR)
 306                 is_char = 1;
 307
 308         switch (expr->type) {
 309         case EXPR_INITIALIZER: {
 310                 struct expression *entry;
 311                 int count = 0;
 312                 int str_len = 0;
 313                 FOR_EACH_PTR(expr->expr_list, entry) {
 314                         count++;
 315                         switch (entry->type) {
 316                         case EXPR_INDEX:
 317                                 if (entry->idx_to >= nr)
 318                                         nr = entry->idx_to+1;
 319                                 break;
 320                         case EXPR_PREOP: {
 321                                 struct expression *e = entry;
 322                                 if (is_char) {
 323                                         while (e && e->type == EXPR_PREOP && e->op == '(')
 324                                                 e = e->unop;
 325                                         if (e && e->type == EXPR_STRING) {
 326                                                 entry = e;
 327                         case EXPR_STRING:
 328                                                 if (is_char)
 329                                                         str_len = entry->string->length;
 330                                         }
 331
 332
 333                                 }
 334                         }
 335                         default:
 336                                 nr++;
 337                         }
 338                 } END_FOR_EACH_PTR(entry);
 339                 if (count == 1 && str_len)
 340                         nr = str_len;
 341                 break;
 342         }
 343         case EXPR_PREOP:
 344                 if (is_char) {
 345                         struct expression *e = expr;
 346                         while (e && e->type == EXPR_PREOP && e->op == '(')
 347                                 e = e->unop;
 348                         if (e && e->type == EXPR_STRING) {
 349                                 expr = e;
 350         case EXPR_STRING:
 351                                 if (is_char)
 352                                         nr = expr->string->length;
 353                         }
 354                 }
 355                 break;
 356         default:
 357                 break;
 358         }
 359         return nr;
 360 }
 361
 362 static struct expression *get_symbol_initializer(struct symbol *sym)
 363 {
 364         do {
 365                 if (sym->initializer)
 366                         return sym->initializer;
 367         } while ((sym = sym->same_symbol) != NULL);
 368         return NULL;
 369 }
 370
 371 static struct symbol * examine_node_type(struct symbol *sym)
 372 {
 373         struct symbol *base_type = examine_base_type(sym);
 374         int bit_size;
 375         unsigned long alignment;
 376
 377         /* SYM_NODE - figure out what the type of the node was.. */
 378         bit_size = 0;
 379         alignment = 0;
 380         if (!base_type)
 381                 return sym;
 382
 383         bit_size = base_type->bit_size;
 384         alignment = base_type->ctype.alignment;
 385
 386         /* Pick up signedness information into the node */
 387         sym->ctype.modifiers |= (MOD_SIGNEDNESS & base_type->ctype.modifiers);
 388
 389         if (!sym->ctype.alignment)
 390                 sym->ctype.alignment = alignment;
 391
 392         /* Unsized array? The size might come from the initializer.. */
 393         if (bit_size < 0 && base_type->type == SYM_ARRAY) {
 394                 struct expression *initializer = get_symbol_initializer(sym);
 395                 if (initializer) {
 396                         struct symbol *node_type = base_type->ctype.base_type;
 397                         int count = count_array_initializer(node_type, initializer);
 398
 399                         if (node_type && node_type->bit_size >= 0)
 400                                 bit_size = node_type->bit_size * count;
 401                 }
 402         }
 403
 404         sym->bit_size = bit_size;
 405         return sym;
 406 }
 407
 408 static struct symbol *examine_enum_type(struct symbol *sym)
 409 {
 410         struct symbol *base_type = examine_base_type(sym);
 411
 412         sym->ctype.modifiers |= (base_type->ctype.modifiers & MOD_SIGNEDNESS);
 413         sym->bit_size = bits_in_enum;
 414         if (base_type->bit_size > sym->bit_size)
 415                 sym->bit_size = base_type->bit_size;
 416         sym->ctype.alignment = enum_alignment;
 417         if (base_type->ctype.alignment > sym->ctype.alignment)
 418                 sym->ctype.alignment = base_type->ctype.alignment;
 419         return sym;
 420 }
 421
 422 static struct symbol *examine_pointer_type(struct symbol *sym)
 423 {
 424         /*
 425          * We need to set the pointer size first, and
 426          * examine the thing we point to only afterwards.
 427          * That's because this pointer type may end up
 428          * being needed for the base type size evaluation.
 429          */
 430         if (!sym->bit_size)
 431                 sym->bit_size = bits_in_pointer;
 432         if (!sym->ctype.alignment)
 433                 sym->ctype.alignment = pointer_alignment;
 434         return sym;
 435 }
 436
 437 /*
 438  * Fill in type size and alignment information for
 439  * regular SYM_TYPE things.
 440  */
 441 struct symbol *examine_symbol_type(struct symbol * sym)
 442 {
 443         if (!sym)
 444                 return sym;
 445
 446         /* Already done? */
 447         if (sym->examined)
 448                 return sym;
 449         sym->examined = 1;
 450
 451         switch (sym->type) {
 452         case SYM_FN:
 453         case SYM_NODE:
 454                 return examine_node_type(sym);
 455         case SYM_ARRAY:
 456                 return examine_array_type(sym);
 457         case SYM_STRUCT:
 458                 return examine_struct_union_type(sym, 1);
 459         case SYM_UNION:
 460                 return examine_struct_union_type(sym, 0);
 461         case SYM_PTR:
 462                 return examine_pointer_type(sym);
 463         case SYM_ENUM:
 464                 return examine_enum_type(sym);
 465         case SYM_BITFIELD:
 466                 return examine_bitfield_type(sym);
 467         case SYM_BASETYPE:
 468                 /* Size and alignment had better already be set up */
 469                 return sym;
 470         case SYM_TYPEOF: {
 471                 struct symbol *base = evaluate_expression(sym->initializer);
 472                 if (base) {
 473                         if (is_bitfield_type(base))
 474                                 warning(base->pos, "typeof applied to bitfield type");
 475                         if (base->type == SYM_NODE)
 476                                 base = base->ctype.base_type;
 477                         sym->type = SYM_NODE;
 478                         sym->ctype.modifiers = 0;
 479                         sym->ctype.base_type = base;
 480                         return examine_node_type(sym);
 481                 }
 482                 break;
 483         }
 484         case SYM_PREPROCESSOR:
 485                 sparse_error(sym->pos, "ctype on preprocessor command? (%s)", show_ident(sym->ident));
 486                 return NULL;
 487         case SYM_UNINITIALIZED:
 488 //              sparse_error(sym->pos, "ctype on uninitialized symbol %p", sym);
 489                 return NULL;
 490         case SYM_RESTRICT:
 491                 examine_base_type(sym);
 492                 return sym;
 493         case SYM_FOULED:
 494                 examine_base_type(sym);
 495                 return sym;
 496         default:
 497                 sparse_error(sym->pos, "Examining unknown symbol type %d", sym->type);
 498                 break;
 499         }
 500         return sym;
 501 }
 502
 503 const char* get_type_name(enum type type)
 504 {
 505         const char *type_lookup[] = {
 506         [SYM_UNINITIALIZED] = "uninitialized",
 507         [SYM_PREPROCESSOR] = "preprocessor",
 508         [SYM_BASETYPE] = "basetype",
 509         [SYM_NODE] = "node",
 510         [SYM_PTR] = "pointer",
 511         [SYM_FN] = "function",
 512         [SYM_ARRAY] = "array",
 513         [SYM_STRUCT] = "struct",
 514         [SYM_UNION] = "union",
 515         [SYM_ENUM] = "enum",
 516         [SYM_TYPEDEF] = "typedef",
 517         [SYM_TYPEOF] = "typeof",
 518         [SYM_MEMBER] = "member",
 519         [SYM_BITFIELD] = "bitfield",
 520         [SYM_LABEL] = "label",
 521         [SYM_RESTRICT] = "restrict",
 522         [SYM_FOULED] = "fouled",
 523         [SYM_KEYWORD] = "keyword",
 524         [SYM_BAD] = "bad"};
 525
 526         if (type <= SYM_BAD)
 527                 return type_lookup[type];
 528         else
 529                 return NULL;
 530 }
 531
 532 struct symbol *examine_pointer_target(struct symbol *sym)
 533 {
 534         return examine_base_type(sym);
 535 }
 536
 537 static struct symbol_list *restr, *fouled;
 538
 539 void create_fouled(struct symbol *type)
 540 {
 541         if (type->bit_size < bits_in_int) {
 542                 struct symbol *new = alloc_symbol(type->pos, type->type);
 543                 *new = *type;
 544                 new->bit_size = bits_in_int;
 545                 new->type = SYM_FOULED;
 546                 new->ctype.base_type = type;
 547                 add_symbol(&restr, type);
 548                 add_symbol(&fouled, new);
 549         }
 550 }
 551
 552 struct symbol *befoul(struct symbol *type)
 553 {
 554         struct symbol *t1, *t2;
 555         while (type->type == SYM_NODE)
 556                 type = type->ctype.base_type;
 557         PREPARE_PTR_LIST(restr, t1);
 558         PREPARE_PTR_LIST(fouled, t2);
 559         for (;;) {
 560                 if (t1 == type)
 561                         return t2;
 562                 if (!t1)
 563                         break;
 564                 NEXT_PTR_LIST(t1);
 565                 NEXT_PTR_LIST(t2);
 566         }
 567         FINISH_PTR_LIST(t2);
 568         FINISH_PTR_LIST(t1);
 569         return NULL;
 570 }
 571
 572 void check_declaration(struct symbol *sym)
 573 {
 574         int warned = 0;
 575         struct symbol *next = sym;
 576
 577         while ((next = next->next_id) != NULL) {
 578                 if (next->namespace != sym->namespace)
 579                         continue;
 580                 if (sym->scope == next->scope) {
 581                         sym->same_symbol = next;
 582                         return;
 583                 }
 584                 /* Extern in block level matches a TOPLEVEL non-static symbol */
 585                 if (sym->ctype.modifiers & MOD_EXTERN) {
 586                         if ((next->ctype.modifiers & (MOD_TOPLEVEL|MOD_STATIC)) == MOD_TOPLEVEL) {
 587                                 sym->same_symbol = next;
 588                                 return;
 589                         }
 590                 }
 591
 592                 if (!Wshadow || warned)
 593                         continue;
 594                 if (get_sym_type(next) == SYM_FN)
 595                         continue;
 596                 warned = 1;
 597                 warning(sym->pos, "symbol '%s' shadows an earlier one", show_ident(sym->ident));
 598                 info(next->pos, "originally declared here");
 599         }
 600 }
 601
 602 void bind_symbol(struct symbol *sym, struct ident *ident, enum namespace ns)
 603 {
 604         struct scope *scope;
 605         if (sym->bound) {
 606                 sparse_error(sym->pos, "internal error: symbol type already bound");
 607                 return;
 608         }
 609         if (ident->reserved && (ns & (NS_TYPEDEF | NS_STRUCT | NS_LABEL | NS_SYMBOL))) {
 610                 sparse_error(sym->pos, "Trying to use reserved word '%s' as identifier", show_ident(ident));
 611                 return;
 612         }
 613         sym->namespace = ns;
 614         sym->next_id = ident->symbols;
 615         ident->symbols = sym;
 616         if (sym->ident && sym->ident != ident)
 617                 warning(sym->pos, "Symbol '%s' already bound", show_ident(sym->ident));
 618         sym->ident = ident;
 619         sym->bound = 1;
 620
 621         scope = block_scope;
 622         if (ns == NS_SYMBOL && toplevel(scope)) {
 623                 unsigned mod = MOD_ADDRESSABLE | MOD_TOPLEVEL;
 624
 625                 scope = global_scope;
 626                 if (sym->ctype.modifiers & MOD_STATIC ||
 627                     is_extern_inline(sym)) {
 628                         scope = file_scope;
 629                         mod = MOD_TOPLEVEL;
 630                 }
 631                 sym->ctype.modifiers |= mod;
 632         }
 633         if (ns == NS_MACRO)
 634                 scope = file_scope;
 635         if (ns == NS_LABEL)
 636                 scope = function_scope;
 637         bind_scope(sym, scope);
 638 }
 639
 640 struct symbol *create_symbol(int stream, const char *name, int type, int namespace)
 641 {
 642         struct token *token = built_in_token(stream, name);
 643         struct symbol *sym = alloc_symbol(token->pos, type);
 644
 645         bind_symbol(sym, token->ident, namespace);
 646         return sym;
 647 }
 648
 649 static int evaluate_to_integer(struct expression *expr)
 650 {
 651         expr->ctype = &int_ctype;
 652         return 1;
 653 }
 654
 655 static int evaluate_expect(struct expression *expr)
 656 {
 657         /* Should we evaluate it to return the type of the first argument? */
 658         expr->ctype = &int_ctype;
 659         return 1;
 660 }
 661
 662 static int arguments_choose(struct expression *expr)
 663 {
 664         struct expression_list *arglist = expr->args;
 665         struct expression *arg;
 666         int i = 0;
 667
 668         FOR_EACH_PTR (arglist, arg) {
 669                 if (!evaluate_expression(arg))
 670                         return 0;
 671                 i++;
 672         } END_FOR_EACH_PTR(arg);
 673         if (i < 3) {
 674                 sparse_error(expr->pos,
 675                              "not enough arguments for __builtin_choose_expr");
 676                 return 0;
 677         } if (i > 3) {
 678                 sparse_error(expr->pos,
 679                              "too many arguments for __builtin_choose_expr");
 680                 return 0;
 681         }
 682         return 1;
 683 }
 684
 685 static int evaluate_choose(struct expression *expr)
 686 {
 687         struct expression_list *list = expr->args;
 688         struct expression *arg, *args[3];
 689         int n = 0;
 690
 691         /* there will be exactly 3; we'd already verified that */
 692         FOR_EACH_PTR(list, arg) {
 693                 args[n++] = arg;
 694         } END_FOR_EACH_PTR(arg);
 695
 696         *expr = get_expression_value(args[0]) ? *args[1] : *args[2];
 697
 698         return 1;
 699 }
 700
 701 static int expand_expect(struct expression *expr, int cost)
 702 {
 703         struct expression *arg = first_ptr_list((struct ptr_list *) expr->args);
 704
 705         if (arg)
 706                 *expr = *arg;
 707         return 0;
 708 }
 709
 710 /*
 711  * __builtin_warning() has type "int" and always returns 1,
 712  * so that you can use it in conditionals or whatever
 713  */
 714 static int expand_warning(struct expression *expr, int cost)
 715 {
 716         struct expression *arg;
 717         struct expression_list *arglist = expr->args;
 718
 719         FOR_EACH_PTR (arglist, arg) {
 720                 /*
 721                  * Constant strings get printed out as a warning. By the
 722                  * time we get here, the EXPR_STRING has been fully
 723                  * evaluated, so by now it's an anonymous symbol with a
 724                  * string initializer.
 725                  *
 726                  * Just for the heck of it, allow any constant string
 727                  * symbol.
 728                  */
 729                 if (arg->type == EXPR_SYMBOL) {
 730                         struct symbol *sym = arg->symbol;
 731                         if (sym->initializer && sym->initializer->type == EXPR_STRING) {
 732                                 struct string *string = sym->initializer->string;
 733                                 warning(expr->pos, "%*s", string->length-1, string->data);
 734                         }
 735                         continue;
 736                 }
 737
 738                 /*
 739                  * Any other argument is a conditional. If it's
 740                  * non-constant, or it is false, we exit and do
 741                  * not print any warning.
 742                  */
 743                 if (arg->type != EXPR_VALUE)
 744                         goto out;
 745                 if (!arg->value)
 746                         goto out;
 747         } END_FOR_EACH_PTR(arg);
 748 out:
 749         expr->type = EXPR_VALUE;
 750         expr->value = 1;
 751         expr->taint = 0;
 752         return 0;
 753 }
 754
 755 static struct symbol_op constant_p_op = {
 756         .evaluate = evaluate_to_integer,
 757         .expand = expand_constant_p
 758 };
 759
 760 static struct symbol_op safe_p_op = {
 761         .evaluate = evaluate_to_integer,
 762         .expand = expand_safe_p
 763 };
 764
 765 static struct symbol_op warning_op = {
 766         .evaluate = evaluate_to_integer,
 767         .expand = expand_warning
 768 };
 769
 770 static struct symbol_op expect_op = {
 771         .evaluate = evaluate_expect,
 772         .expand = expand_expect
 773 };
 774
 775 static struct symbol_op choose_op = {
 776         .evaluate = evaluate_choose,
 777         .args = arguments_choose,
 778 };
 779
 780 /*
 781  * Builtin functions
 782  */
 783 static struct symbol builtin_fn_type = { .type = SYM_FN /* , .variadic =1 */ };
 784 static struct sym_init {
 785         const char *name;
 786         struct symbol *base_type;
 787         unsigned int modifiers;
 788         struct symbol_op *op;
 789 } eval_init_table[] = {
 790         { "__builtin_constant_p", &builtin_fn_type, MOD_TOPLEVEL, &constant_p_op },
 791         { "__builtin_safe_p", &builtin_fn_type, MOD_TOPLEVEL, &safe_p_op },
 792         { "__builtin_warning", &builtin_fn_type, MOD_TOPLEVEL, &warning_op },
 793         { "__builtin_expect", &builtin_fn_type, MOD_TOPLEVEL, &expect_op },
 794         { "__builtin_choose_expr", &builtin_fn_type, MOD_TOPLEVEL, &choose_op },
 795         { NULL,         NULL,           0 }
 796 };
 797
 798 /*
 799  * Default empty attribute
 800  */
 801 struct attribute null_attr = {};
 802
 803 /*
 804  * Abstract types
 805  */
 806 struct symbol   int_type,
 807                 fp_type;
 808
 809 /*
 810  * C types (i.e. actual instances that the abstract types
 811  * can map onto)
 812  */
 813 struct symbol   bool_ctype, void_ctype, type_ctype,
 814                 char_ctype, schar_ctype, uchar_ctype,
 815                 short_ctype, sshort_ctype, ushort_ctype,
 816                 int_ctype, sint_ctype, uint_ctype,
 817                 long_ctype, slong_ctype, ulong_ctype,
 818                 llong_ctype, sllong_ctype, ullong_ctype,
 819                 lllong_ctype, slllong_ctype, ulllong_ctype,
 820                 float_ctype, double_ctype, ldouble_ctype,
 821                 string_ctype, ptr_ctype, lazy_ptr_ctype,
 822                 incomplete_ctype, label_ctype, bad_ctype,
 823                 null_ctype;
 824
 825 struct symbol   zero_int;
 826
 827 #define __INIT_IDENT(str, res) { .len = sizeof(str)-1, .name = str, .reserved = res }
 828 #define __IDENT(n,str,res) \
 829         struct ident n  = __INIT_IDENT(str,res)
 830
 831 #include "ident-list.h"
 832
 833 void init_symbols(void)
 834 {
 835         int stream = init_stream("builtin", -1, includepath);
 836         struct sym_init *ptr;
 837
 838 #define __IDENT(n,str,res) \
 839         hash_ident(&n)
 840 #include "ident-list.h"
 841
 842         init_parser(stream);
 843
 844         builtin_fn_type.variadic = 1;
 845         builtin_fn_type.ctype.attribute = &null_attr;
 846         for (ptr = eval_init_table; ptr->name; ptr++) {
 847                 struct symbol *sym;
 848                 sym = create_symbol(stream, ptr->name, SYM_NODE, NS_SYMBOL);
 849                 sym->ctype.base_type = ptr->base_type;
 850                 sym->ctype.modifiers = ptr->modifiers;
 851                 sym->ctype.attribute = &null_attr;
 852                 sym->op = ptr->op;
 853         }
 854 }
 855
 856 #ifdef __CHAR_UNSIGNED__
 857 #define CHAR_SIGNEDNESS MOD_UNSIGNED
 858 #else
 859 #define CHAR_SIGNEDNESS MOD_SIGNED
 860 #endif
 861
 862 #define MOD_ESIGNED (MOD_SIGNED | MOD_EXPLICITLY_SIGNED)
 863 #define MOD_LL (MOD_LONG | MOD_LONGLONG)
 864 #define MOD_LLL MOD_LONGLONGLONG
 865 static const struct ctype_declare {
 866         struct symbol *ptr;
 867         enum type type;
 868         unsigned long modifiers;
 869         int *bit_size;
 870         int *maxalign;
 871         struct symbol *base_type;
 872 } ctype_declaration[] = {
 873         { &bool_ctype,      SYM_BASETYPE, MOD_UNSIGNED,             &bits_in_bool,           &max_int_alignment, &int_type },
 874         { &void_ctype,      SYM_BASETYPE, 0,                        NULL,            NULL,               NULL },
 875         { &type_ctype,      SYM_BASETYPE, MOD_TYPE,                 NULL,                    NULL,               NULL },
 876         { &incomplete_ctype,SYM_BASETYPE, 0,                        NULL,                    NULL,               NULL },
 877         { &bad_ctype,       SYM_BASETYPE, 0,                        NULL,                    NULL,               NULL },
 878
 879         { &char_ctype,      SYM_BASETYPE, CHAR_SIGNEDNESS | MOD_CHAR,    &bits_in_char,      &max_int_alignment, &int_type },
 880         { &schar_ctype,     SYM_BASETYPE, MOD_ESIGNED | MOD_CHAR,   &bits_in_char,           &max_int_alignment, &int_type },
 881         { &uchar_ctype,     SYM_BASETYPE, MOD_UNSIGNED | MOD_CHAR,  &bits_in_char,           &max_int_alignment, &int_type },
 882         { &short_ctype,     SYM_BASETYPE, MOD_SIGNED | MOD_SHORT,   &bits_in_short,          &max_int_alignment, &int_type },
 883         { &sshort_ctype,    SYM_BASETYPE, MOD_ESIGNED | MOD_SHORT,  &bits_in_short,          &max_int_alignment, &int_type },
 884         { &ushort_ctype,    SYM_BASETYPE, MOD_UNSIGNED | MOD_SHORT, &bits_in_short,          &max_int_alignment, &int_type },
 885         { &int_ctype,       SYM_BASETYPE, MOD_SIGNED,               &bits_in_int,            &max_int_alignment, &int_type },
 886         { &sint_ctype,      SYM_BASETYPE, MOD_ESIGNED,              &bits_in_int,            &max_int_alignment, &int_type },
 887         { &uint_ctype,      SYM_BASETYPE, MOD_UNSIGNED,             &bits_in_int,            &max_int_alignment, &int_type },
 888         { &long_ctype,      SYM_BASETYPE, MOD_SIGNED | MOD_LONG,    &bits_in_long,           &max_int_alignment, &int_type },
 889         { &slong_ctype,     SYM_BASETYPE, MOD_ESIGNED | MOD_LONG,   &bits_in_long,           &max_int_alignment, &int_type },
 890         { &ulong_ctype,     SYM_BASETYPE, MOD_UNSIGNED | MOD_LONG,  &bits_in_long,           &max_int_alignment, &int_type },
 891         { &llong_ctype,     SYM_BASETYPE, MOD_SIGNED | MOD_LL,      &bits_in_longlong,       &max_int_alignment, &int_type },
 892         { &sllong_ctype,    SYM_BASETYPE, MOD_ESIGNED | MOD_LL,     &bits_in_longlong,       &max_int_alignment, &int_type },
 893         { &ullong_ctype,    SYM_BASETYPE, MOD_UNSIGNED | MOD_LL,    &bits_in_longlong,       &max_int_alignment, &int_type },
 894         { &lllong_ctype,    SYM_BASETYPE, MOD_SIGNED | MOD_LLL,     &bits_in_longlonglong,   &max_int_alignment, &int_type },
 895         { &slllong_ctype,   SYM_BASETYPE, MOD_ESIGNED | MOD_LLL,    &bits_in_longlonglong,   &max_int_alignment, &int_type },
 896         { &ulllong_ctype,   SYM_BASETYPE, MOD_UNSIGNED | MOD_LLL,   &bits_in_longlonglong,   &max_int_alignment, &int_type },
 897
 898         { &float_ctype,     SYM_BASETYPE,  0,                       &bits_in_float,          &max_fp_alignment,  &fp_type },
 899         { &double_ctype,    SYM_BASETYPE, MOD_LONG,                 &bits_in_double,         &max_fp_alignment,  &fp_type },
 900         { &ldouble_ctype,   SYM_BASETYPE, MOD_LONG | MOD_LONGLONG,  &bits_in_longdouble,     &max_fp_alignment,  &fp_type },
 901
 902         { &string_ctype,    SYM_PTR,      0,                        &bits_in_pointer,        &pointer_alignment, &char_ctype },
 903         { &ptr_ctype,       SYM_PTR,      0,                        &bits_in_pointer,        &pointer_alignment, &void_ctype },
 904         { &null_ctype,      SYM_PTR,      0,                        &bits_in_pointer,        &pointer_alignment, &void_ctype },
 905         { &label_ctype,     SYM_PTR,      0,                        &bits_in_pointer,        &pointer_alignment, &void_ctype },
 906         { &lazy_ptr_ctype,  SYM_PTR,      0,                        &bits_in_pointer,        &pointer_alignment, &void_ctype },
 907         { NULL, }
 908 };
 909 #undef MOD_LLL
 910 #undef MOD_LL
 911 #undef MOD_ESIGNED
 912
 913 void init_ctype(void)
 914 {
 915         const struct ctype_declare *ctype;
 916
 917         for (ctype = ctype_declaration ; ctype->ptr; ctype++) {
 918                 struct symbol *sym = ctype->ptr;
 919                 unsigned long bit_size = ctype->bit_size ? *ctype->bit_size : -1;
 920                 unsigned long maxalign = ctype->maxalign ? *ctype->maxalign : 0;
 921                 unsigned long alignment = bits_to_bytes(bit_size);
 922
 923                 if (alignment > maxalign)
 924                         alignment = maxalign;
 925                 sym->type = ctype->type;
 926                 sym->bit_size = bit_size;
 927                 sym->ctype.alignment = alignment;
 928                 sym->ctype.base_type = ctype->base_type;
 929                 sym->ctype.modifiers = ctype->modifiers;
 930                 sym->ctype.attribute = &null_attr;
 931         }
 932 }