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