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     scope->next = table->current_scope;
 176     table->current_scope = scope;
 177     table->depth++;
 178 }
 179
 180
 181 static struct symbol_header *
 182 find_symbol(struct _mesa_symbol_table *table, const char *name)
 183 {
 184     return (struct symbol_header *) hash_table_find(table->ht, name);
 185 }
 186
 187
 188 /**
 189  * Determine the scope "distance" of a symbol from the current scope
 190  *
 191  * \return
 192  * A non-negative number for the number of scopes between the current scope
 193  * and the scope where a symbol was defined.  A value of zero means the current
 194  * scope.  A negative number if the symbol does not exist.
 195  */
 196 int
 197 _mesa_symbol_table_symbol_scope(struct _mesa_symbol_table *table,
 198                                 int name_space, const char *name)
 199 {
 200     struct symbol_header *const hdr = find_symbol(table, name);
 201     struct symbol *sym;
 202
 203     if (hdr != NULL) {
 204        for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {
 205           assert(sym->hdr == hdr);
 206
 207           if ((name_space == -1) || (sym->name_space == name_space)) {
 208              assert(sym->depth <= table->depth);
 209              return sym->depth - table->depth;
 210           }
 211        }
 212     }
 213
 214     return -1;
 215 }
 216
 217
 218 void *
 219 _mesa_symbol_table_find_symbol(struct _mesa_symbol_table *table,
 220                                int name_space, const char *name)
 221 {
 222     struct symbol_header *const hdr = find_symbol(table, name);
 223
 224     if (hdr != NULL) {
 225         struct symbol *sym;
 226
 227
 228         for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {
 229             assert(sym->hdr == hdr);
 230
 231             if ((name_space == -1) || (sym->name_space == name_space)) {
 232                 return sym->data;
 233             }
 234         }
 235     }
 236
 237     return NULL;
 238 }
 239
 240
 241 int
 242 _mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,
 243                               int name_space, const char *name,
 244                               void *declaration)
 245 {
 246     struct symbol_header *hdr;
 247     struct symbol *sym;
 248
 249     check_symbol_table(table);
 250
 251     hdr = find_symbol(table, name);
 252
 253     check_symbol_table(table);
 254
 255     if (hdr == NULL) {
 256        hdr = calloc(1, sizeof(*hdr));
 257        hdr->name = strdup(name);
 258
 259        hash_table_insert(table->ht, hdr, hdr->name);
 260        hdr->next = table->hdr;
 261        table->hdr = hdr;
 262     }
 263
 264     check_symbol_table(table);
 265
 266     /* If the symbol already exists in this namespace at this scope, it cannot
 267      * be added to the table.
 268      */
 269     for (sym = hdr->symbols
 270          ; (sym != NULL) && (sym->name_space != name_space)
 271          ; sym = sym->next_with_same_name) {
 272        /* empty */
 273     }
 274
 275     if (sym && (sym->depth == table->depth))
 276        return -1;
 277
 278     sym = calloc(1, sizeof(*sym));
 279     sym->next_with_same_name = hdr->symbols;
 280     sym->next_with_same_scope = table->current_scope->symbols;
 281     sym->hdr = hdr;
 282     sym->name_space = name_space;
 283     sym->data = declaration;
 284     sym->depth = table->depth;
 285
 286     assert(sym->hdr == hdr);
 287
 288     hdr->symbols = sym;
 289     table->current_scope->symbols = sym;
 290
 291     check_symbol_table(table);
 292     return 0;
 293 }
 294
 295
 296 int
 297 _mesa_symbol_table_add_global_symbol(struct _mesa_symbol_table *table,
 298                                      int name_space, const char *name,
 299                                      void *declaration)
 300 {
 301     struct symbol_header *hdr;
 302     struct symbol *sym;
 303     struct symbol *curr;
 304     struct scope_level *top_scope;
 305
 306     check_symbol_table(table);
 307
 308     hdr = find_symbol(table, name);
 309
 310     check_symbol_table(table);
 311
 312     if (hdr == NULL) {
 313         hdr = calloc(1, sizeof(*hdr));
 314         hdr->name = strdup(name);
 315
 316         hash_table_insert(table->ht, hdr, hdr->name);
 317         hdr->next = table->hdr;
 318         table->hdr = hdr;
 319     }
 320
 321     check_symbol_table(table);
 322
 323     /* If the symbol already exists in this namespace at this scope, it cannot
 324      * be added to the table.
 325      */
 326     for (sym = hdr->symbols
 327          ; (sym != NULL) && (sym->name_space != name_space)
 328          ; sym = sym->next_with_same_name) {
 329        /* empty */
 330     }
 331
 332     if (sym && sym->depth == 0)
 333        return -1;
 334
 335     /* Find the top-level scope */
 336     for (top_scope = table->current_scope
 337          ; top_scope->next != NULL
 338          ; top_scope = top_scope->next) {
 339        /* empty */
 340     }
 341
 342     sym = calloc(1, sizeof(*sym));
 343     sym->next_with_same_scope = top_scope->symbols;
 344     sym->hdr = hdr;
 345     sym->name_space = name_space;
 346     sym->data = declaration;
 347
 348     assert(sym->hdr == hdr);
 349
 350     /* Since next_with_same_name is ordered by scope, we need to append the
 351      * new symbol to the _end_ of the list.
 352      */
 353     if (hdr->symbols == NULL) {
 354        hdr->symbols = sym;
 355     } else {
 356        for (curr = hdr->symbols
 357             ; curr->next_with_same_name != NULL
 358             ; curr = curr->next_with_same_name) {
 359           /* empty */
 360        }
 361        curr->next_with_same_name = sym;
 362     }
 363     top_scope->symbols = sym;
 364
 365     check_symbol_table(table);
 366     return 0;
 367 }
 368
 369
 370
 371 struct _mesa_symbol_table *
 372 _mesa_symbol_table_ctor(void)
 373 {
 374     struct _mesa_symbol_table *table = calloc(1, sizeof(*table));
 375
 376     if (table != NULL) {
 377        table->ht = hash_table_ctor(32, hash_table_string_hash,
 378                                    hash_table_string_compare);
 379
 380        _mesa_symbol_table_push_scope(table);
 381     }
 382
 383     return table;
 384 }
 385
 386
 387 void
 388 _mesa_symbol_table_dtor(struct _mesa_symbol_table *table)
 389 {
 390    struct symbol_header *hdr;
 391    struct symbol_header *next;
 392
 393    while (table->current_scope != NULL) {
 394       _mesa_symbol_table_pop_scope(table);
 395    }
 396
 397    for (hdr = table->hdr; hdr != NULL; hdr = next) {
 398        next = hdr->next;
 399        free(hdr->name);
 400        free(hdr);
 401    }
 402
 403    hash_table_dtor(table->ht);
 404    free(table);
 405 }