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