src/mesa/program/symbol_table.c

   1 /*
   2  * Copyright © 2008 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include "main/imports.h"
  25 #include "symbol_table.h"
  26 #include "hash_table.h"
  27
  28 struct symbol {
  29     /**
  30      * Link to the next symbol in the table with the same name
  31      *
  32      * The linked list of symbols with the same name is ordered by scope
  33      * from inner-most to outer-most.
  34      */
  35     struct symbol *next_with_same_name;
  36
  37
  38     /**
  39      * Link to the next symbol in the table with the same scope
  40      *
  41      * The linked list of symbols with the same scope is unordered.  Symbols
  42      * in this list my have unique names.
  43      */
  44     struct symbol *next_with_same_scope;
  45
  46
  47     /**
  48      * Header information for the list of symbols with the same name.
  49      */
  50     struct symbol_header *hdr;
  51
  52
  53     /**
  54      * Name space of the symbol
  55      *
  56      * Name space are arbitrary user assigned integers.  No two symbols can
  57      * exist in the same name space at the same scope level.
  58      */
  59     int name_space;
  60
  61     /** Scope depth where this symbol was defined. */
  62     unsigned depth;
  63
  64     /**
  65      * Arbitrary user supplied data.
  66      */
  67     void *data;
  68 };
  69
  70
  71 /**
  72  */
  73 struct symbol_header {
  74     /** Linkage in list of all headers in a given symbol table. */
  75     struct symbol_header *next;
  76
  77     /** Symbol name. */
  78     char *name;
  79
  80     /** Linked list of symbols with the same name. */
  81     struct symbol *symbols;
  82 };
  83
  84
  85 /**
  86  * Element of the scope stack.
  87  */
  88 struct scope_level {
  89     /** Link to next (inner) scope level. */
  90     struct scope_level *next;
  91
  92     /** Linked list of symbols with the same scope. */
  93     struct symbol *symbols;
  94 };
  95
  96
  97 /**
  98  *
  99  */
 100 struct _mesa_symbol_table {
 101     /** Hash table containing all symbols in the symbol table. */
 102     struct hash_table *ht;
 103
 104     /** Top of scope stack. */
 105     struct scope_level *current_scope;
 106
 107     /** List of all symbol headers in the table. */
 108     struct symbol_header *hdr;
 109
 110     /** Current scope depth. */
 111     unsigned depth;
 112 };
 113
 114
 115 static void
 116 check_symbol_table(struct _mesa_symbol_table *table)
 117 {
 118 #if !defined(NDEBUG)
 119     struct scope_level *scope;
 120
 121     for (scope = table->current_scope; scope != NULL; scope = scope->next) {
 122         struct symbol *sym;
 123
 124         for (sym = scope->symbols
 125              ; sym != NULL
 126              ; sym = sym->next_with_same_name) {
 127             const struct symbol_header *const hdr = sym->hdr;
 128             struct symbol *sym2;
 129
 130             for (sym2 = hdr->symbols
 131                  ; sym2 != NULL
 132                  ; sym2 = sym2->next_with_same_name) {
 133                 assert(sym2->hdr == hdr);
 134             }
 135         }
 136     }
 137 #else
 138     (void) table;
 139 #endif /* !defined(NDEBUG) */
 140 }
 141
 142 void
 143 _mesa_symbol_table_pop_scope(struct _mesa_symbol_table *table)
 144 {
 145     struct scope_level *const scope = table->current_scope;
 146     struct symbol *sym = scope->symbols;
 147
 148     table->current_scope = scope->next;
 149     table->depth--;
 150
 151     free(scope);
 152
 153     while (sym != NULL) {
 154         struct symbol *const next = sym->next_with_same_scope;
 155         struct symbol_header *const hdr = sym->hdr;
 156
 157         assert(hdr->symbols == sym);
 158
 159         hdr->symbols = sym->next_with_same_name;
 160
 161         free(sym);
 162
 163         sym = next;
 164     }
 165
 166     check_symbol_table(table);
 167 }
 168
 169
 170 void
 171 _mesa_symbol_table_push_scope(struct _mesa_symbol_table *table)
 172 {
 173     struct scope_level *const scope = calloc(1, sizeof(*scope));
 174
 175     if (scope == NULL) {
 176        _mesa_error_no_memory(__func__);
 177        return;
 178     }
 179
 180     scope->next = table->current_scope;
 181     table->current_scope = scope;
 182     table->depth++;
 183 }
 184
 185
 186 static struct symbol_header *
 187 find_symbol(struct _mesa_symbol_table *table, const char *name)
 188 {
 189     return (struct symbol_header *) hash_table_find(table->ht, name);
 190 }
 191
 192
 193 /**
 194  * Determine the scope "distance" of a symbol from the current scope
 195  *
 196  * \return
 197  * A non-negative number for the number of scopes between the current scope
 198  * and the scope where a symbol was defined.  A value of zero means the current
 199  * scope.  A negative number if the symbol does not exist.
 200  */
 201 int
 202 _mesa_symbol_table_symbol_scope(struct _mesa_symbol_table *table,
 203                                 int name_space, const char *name)
 204 {
 205     struct symbol_header *const hdr = find_symbol(table, name);
 206     struct symbol *sym;
 207
 208     if (hdr != NULL) {
 209        for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {
 210           assert(sym->hdr == hdr);
 211
 212           if ((name_space == -1) || (sym->name_space == name_space)) {
 213              assert(sym->depth <= table->depth);
 214              return sym->depth - table->depth;
 215           }
 216        }
 217     }
 218
 219     return -1;
 220 }
 221
 222
 223 void *
 224 _mesa_symbol_table_find_symbol(struct _mesa_symbol_table *table,
 225                                int name_space, const char *name)
 226 {
 227     struct symbol_header *const hdr = find_symbol(table, name);
 228
 229     if (hdr != NULL) {
 230         struct symbol *sym;
 231
 232
 233         for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {
 234             assert(sym->hdr == hdr);
 235
 236             if ((name_space == -1) || (sym->name_space == name_space)) {
 237                 return sym->data;
 238             }
 239         }
 240     }
 241
 242     return NULL;
 243 }
 244
 245
 246 int
 247 _mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,
 248                               int name_space, const char *name,
 249                               void *declaration)
 250 {
 251     struct symbol_header *hdr;
 252     struct symbol *sym;
 253
 254     check_symbol_table(table);
 255
 256     hdr = find_symbol(table, name);
 257
 258     check_symbol_table(table);
 259
 260     if (hdr == NULL) {
 261        hdr = calloc(1, sizeof(*hdr));
 262        if (hdr == NULL) {
 263           _mesa_error_no_memory(__func__);
 264           return -1;
 265        }
 266
 267        hdr->name = strdup(name);
 268        if (hdr->name == NULL) {
 269           free(hdr);
 270           _mesa_error_no_memory(__func__);
 271           return -1;
 272        }
 273
 274        hash_table_insert(table->ht, hdr, hdr->name);
 275        hdr->next = table->hdr;
 276        table->hdr = hdr;
 277     }
 278
 279     check_symbol_table(table);
 280
 281     /* If the symbol already exists in this namespace at this scope, it cannot
 282      * be added to the table.
 283      */
 284     for (sym = hdr->symbols
 285          ; (sym != NULL) && (sym->name_space != name_space)
 286          ; sym = sym->next_with_same_name) {
 287        /* empty */
 288     }
 289
 290     if (sym && (sym->depth == table->depth))
 291        return -1;
 292
 293     sym = calloc(1, sizeof(*sym));
 294     if (sym == NULL) {
 295        _mesa_error_no_memory(__func__);
 296        return -1;
 297     }
 298
 299     sym->next_with_same_name = hdr->symbols;
 300     sym->next_with_same_scope = table->current_scope->symbols;
 301     sym->hdr = hdr;
 302     sym->name_space = name_space;
 303     sym->data = declaration;
 304     sym->depth = table->depth;
 305
 306     assert(sym->hdr == hdr);
 307
 308     hdr->symbols = sym;
 309     table->current_scope->symbols = sym;
 310
 311     check_symbol_table(table);
 312     return 0;
 313 }
 314
 315
 316 int
 317 _mesa_symbol_table_add_global_symbol(struct _mesa_symbol_table *table,
 318                                      int name_space, const char *name,
 319                                      void *declaration)
 320 {
 321     struct symbol_header *hdr;
 322     struct symbol *sym;
 323     struct symbol *curr;
 324     struct scope_level *top_scope;
 325
 326     check_symbol_table(table);
 327
 328     hdr = find_symbol(table, name);
 329
 330     check_symbol_table(table);
 331
 332     if (hdr == NULL) {
 333         hdr = calloc(1, sizeof(*hdr));
 334         if (hdr == NULL) {
 335            _mesa_error_no_memory(__func__);
 336            return -1;
 337         }
 338
 339         hdr->name = strdup(name);
 340
 341         hash_table_insert(table->ht, hdr, hdr->name);
 342         hdr->next = table->hdr;
 343         table->hdr = hdr;
 344     }
 345
 346     check_symbol_table(table);
 347
 348     /* If the symbol already exists in this namespace at this scope, it cannot
 349      * be added to the table.
 350      */
 351     for (sym = hdr->symbols
 352          ; (sym != NULL) && (sym->name_space != name_space)
 353          ; sym = sym->next_with_same_name) {
 354        /* empty */
 355     }
 356
 357     if (sym && sym->depth == 0)
 358        return -1;
 359
 360     /* Find the top-level scope */
 361     for (top_scope = table->current_scope
 362          ; top_scope->next != NULL
 363          ; top_scope = top_scope->next) {
 364        /* empty */
 365     }
 366
 367     sym = calloc(1, sizeof(*sym));
 368     if (sym == NULL) {
 369        _mesa_error_no_memory(__func__);
 370        return -1;
 371     }
 372
 373     sym->next_with_same_scope = top_scope->symbols;
 374     sym->hdr = hdr;
 375     sym->name_space = name_space;
 376     sym->data = declaration;
 377
 378     assert(sym->hdr == hdr);
 379
 380     /* Since next_with_same_name is ordered by scope, we need to append the
 381      * new symbol to the _end_ of the list.
 382      */
 383     if (hdr->symbols == NULL) {
 384        hdr->symbols = sym;
 385     } else {
 386        for (curr = hdr->symbols
 387             ; curr->next_with_same_name != NULL
 388             ; curr = curr->next_with_same_name) {
 389           /* empty */
 390        }
 391        curr->next_with_same_name = sym;
 392     }
 393     top_scope->symbols = sym;
 394
 395     check_symbol_table(table);
 396     return 0;
 397 }
 398
 399
 400
 401 struct _mesa_symbol_table *
 402 _mesa_symbol_table_ctor(void)
 403 {
 404     struct _mesa_symbol_table *table = calloc(1, sizeof(*table));
 405
 406     if (table != NULL) {
 407        table->ht = hash_table_ctor(32, hash_table_string_hash,
 408                                    hash_table_string_compare);
 409
 410        _mesa_symbol_table_push_scope(table);
 411     }
 412
 413     return table;
 414 }
 415
 416
 417 void
 418 _mesa_symbol_table_dtor(struct _mesa_symbol_table *table)
 419 {
 420    struct symbol_header *hdr;
 421    struct symbol_header *next;
 422
 423    while (table->current_scope != NULL) {
 424       _mesa_symbol_table_pop_scope(table);
 425    }
 426
 427    for (hdr = table->hdr; hdr != NULL; hdr = next) {
 428        next = hdr->next;
 429        free(hdr->name);
 430        free(hdr);
 431    }
 432
 433    hash_table_dtor(table->ht);
 434    free(table);
 435 }