smatch_function_hooks.c

   1 /*
   2  * sparse/smatch_function_hooks.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * There are several types of function hooks:
  12  * add_function_hook()        - For any time a function is called.
  13  * add_function_assign_hook() - foo = the_function().
  14  * add_implied_return_hook()  - Calculates the implied return value.
  15  * add_macro_assign_hook()    - foo = the_macro().
  16  * return_implies_state()     - For when a return value of 1 implies locked
  17  *                              and 0 implies unlocked. etc. etc.
  18  *
  19  */
  20
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include "smatch.h"
  24 #include "smatch_slist.h"
  25 #include "smatch_extra.h"
  26 #include "smatch_function_hashtable.h"
  27
  28 struct fcall_back {
  29         int type;
  30         struct data_range *range;
  31         union {
  32                 func_hook *call_back;
  33                 implication_hook *ranged;
  34                 implied_return_hook *implied_return;
  35         } u;
  36         void *info;
  37 };
  38
  39 ALLOCATOR(fcall_back, "call backs");
  40 DECLARE_PTR_LIST(call_back_list, struct fcall_back);
  41
  42 DEFINE_FUNCTION_HASHTABLE_STATIC(callback, struct fcall_back, struct call_back_list);
  43 static struct hashtable *func_hash;
  44
  45 #define REGULAR_CALL       0
  46 #define RANGED_CALL        1
  47 #define ASSIGN_CALL        2
  48 #define IMPLIED_RETURN     3
  49 #define MACRO_ASSIGN       4
  50 #define MACRO_ASSIGN_EXTRA 5
  51
  52 struct return_implies_callback {
  53         int type;
  54         return_implies_hook *callback;
  55 };
  56 ALLOCATOR(return_implies_callback, "return_implies callbacks");
  57 DECLARE_PTR_LIST(db_implies_list, struct return_implies_callback);
  58 static struct db_implies_list *db_implies_list;
  59 static struct db_implies_list *db_return_states_list;
  60
  61 static struct fcall_back *alloc_fcall_back(int type, void *call_back,
  62                                            void *info)
  63 {
  64         struct fcall_back *cb;
  65
  66         cb = __alloc_fcall_back(0);
  67         cb->type = type;
  68         cb->u.call_back = call_back;
  69         cb->info = info;
  70         return cb;
  71 }
  72
  73 void add_function_hook(const char *look_for, func_hook *call_back, void *info)
  74 {
  75         struct fcall_back *cb;
  76
  77         cb = alloc_fcall_back(REGULAR_CALL, call_back, info);
  78         add_callback(func_hash, look_for, cb);
  79 }
  80
  81 void add_function_assign_hook(const char *look_for, func_hook *call_back,
  82                               void *info)
  83 {
  84         struct fcall_back *cb;
  85
  86         cb = alloc_fcall_back(ASSIGN_CALL, call_back, info);
  87         add_callback(func_hash, look_for, cb);
  88 }
  89
  90 void add_implied_return_hook(const char *look_for,
  91                              implied_return_hook *call_back,
  92                              void *info)
  93 {
  94         struct fcall_back *cb;
  95
  96         cb = alloc_fcall_back(IMPLIED_RETURN, call_back, info);
  97         add_callback(func_hash, look_for, cb);
  98 }
  99
 100 void add_macro_assign_hook(const char *look_for, func_hook *call_back,
 101                         void *info)
 102 {
 103         struct fcall_back *cb;
 104
 105         cb = alloc_fcall_back(MACRO_ASSIGN, call_back, info);
 106         add_callback(func_hash, look_for, cb);
 107 }
 108
 109 void add_macro_assign_hook_extra(const char *look_for, func_hook *call_back,
 110                         void *info)
 111 {
 112         struct fcall_back *cb;
 113
 114         cb = alloc_fcall_back(MACRO_ASSIGN_EXTRA, call_back, info);
 115         add_callback(func_hash, look_for, cb);
 116 }
 117
 118 void return_implies_state(const char *look_for, long long start, long long end,
 119                          implication_hook *call_back, void *info)
 120 {
 121         struct fcall_back *cb;
 122
 123         cb = alloc_fcall_back(RANGED_CALL, call_back, info);
 124         cb->range = alloc_range_perm(start, end);
 125         add_callback(func_hash, look_for, cb);
 126 }
 127
 128 void add_db_return_implies_callback(int type, return_implies_hook *callback)
 129 {
 130         struct return_implies_callback *cb = __alloc_return_implies_callback(0);
 131
 132         cb->type = type;
 133         cb->callback = callback;
 134         add_ptr_list(&db_implies_list, cb);
 135 }
 136
 137 void add_db_return_states_callback(int type, return_implies_hook *callback)
 138 {
 139         struct return_implies_callback *cb = __alloc_return_implies_callback(0);
 140
 141         cb->type = type;
 142         cb->callback = callback;
 143         add_ptr_list(&db_return_states_list, cb);
 144 }
 145
 146 static int call_call_backs(struct call_back_list *list, int type,
 147                             const char *fn, struct expression *expr)
 148 {
 149         struct fcall_back *tmp;
 150         int handled = 0;
 151
 152         FOR_EACH_PTR(list, tmp) {
 153                 if (tmp->type == type) {
 154                         (tmp->u.call_back)(fn, expr, tmp->info);
 155                         handled = 1;
 156                 }
 157         } END_FOR_EACH_PTR(tmp);
 158
 159         return handled;
 160 }
 161
 162 static void call_ranged_call_backs(struct call_back_list *list,
 163                                 const char *fn, struct expression *call_expr,
 164                                 struct expression *assign_expr)
 165 {
 166         struct fcall_back *tmp;
 167
 168         FOR_EACH_PTR(list, tmp) {
 169                 (tmp->u.ranged)(fn, call_expr, assign_expr, tmp->info);
 170         } END_FOR_EACH_PTR(tmp);
 171 }
 172
 173 static struct call_back_list *get_same_ranged_call_backs(struct call_back_list *list,
 174                                                 struct data_range *drange)
 175 {
 176         struct call_back_list *ret = NULL;
 177         struct fcall_back *tmp;
 178
 179         FOR_EACH_PTR(list, tmp) {
 180                 if (tmp->type != RANGED_CALL)
 181                         continue;
 182                 if (tmp->range->min == drange->min && tmp->range->max == drange->max)
 183                         add_ptr_list(&ret, tmp);
 184         } END_FOR_EACH_PTR(tmp);
 185         return ret;
 186 }
 187
 188 static int assign_ranged_funcs(const char *fn, struct expression *expr,
 189                                  struct call_back_list *call_backs)
 190 {
 191         struct fcall_back *tmp;
 192         struct sm_state *sm;
 193         char *var_name;
 194         struct symbol *sym;
 195         struct smatch_state *estate;
 196         struct state_list *tmp_slist;
 197         struct state_list *final_states = NULL;
 198         struct range_list *handled_ranges = NULL;
 199         struct call_back_list *same_range_call_backs = NULL;
 200         int handled = 0;
 201
 202         if (!call_backs)
 203                 return 0;
 204
 205         var_name = get_variable_from_expr(expr->left, &sym);
 206         if (!var_name || !sym)
 207                 goto free;
 208
 209         FOR_EACH_PTR(call_backs, tmp) {
 210                 if (tmp->type != RANGED_CALL)
 211                         continue;
 212                 if (in_list_exact(handled_ranges, tmp->range))
 213                         continue;
 214                 __push_fake_cur_slist();
 215                 tack_on(&handled_ranges, tmp->range);
 216
 217                 same_range_call_backs = get_same_ranged_call_backs(call_backs, tmp->range);
 218                 call_ranged_call_backs(same_range_call_backs, fn, expr->right, expr);
 219                 __free_ptr_list((struct ptr_list **)&same_range_call_backs);
 220
 221                 estate = alloc_estate_range(tmp->range->min, tmp->range->max);
 222                 set_extra_mod(var_name, sym, estate);
 223
 224                 tmp_slist = __pop_fake_cur_slist();
 225                 merge_slist(&final_states, tmp_slist);
 226                 free_slist(&tmp_slist);
 227                 handled = 1;
 228         } END_FOR_EACH_PTR(tmp);
 229
 230         FOR_EACH_PTR(final_states, sm) {
 231                 __set_sm(sm);
 232         } END_FOR_EACH_PTR(sm);
 233
 234         free_slist(&final_states);
 235 free:
 236         free_string(var_name);
 237         return handled;
 238 }
 239
 240 int call_implies_callbacks(int comparison, struct expression *expr, long long value, int left)
 241 {
 242         struct call_back_list *call_backs;
 243         struct fcall_back *tmp;
 244         const char *fn;
 245         struct data_range *value_range;
 246         struct state_list *true_states = NULL;
 247         struct state_list *false_states = NULL;
 248         struct state_list *tmp_slist;
 249         struct sm_state *sm;
 250
 251         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
 252                 return 0;
 253         fn = expr->fn->symbol->ident->name;
 254         call_backs = search_callback(func_hash, (char *)expr->fn->symbol->ident->name);
 255         if (!call_backs)
 256                 return 0;
 257         value_range = alloc_range(value, value);
 258
 259         /* set true states */
 260         __push_fake_cur_slist();
 261         FOR_EACH_PTR(call_backs, tmp) {
 262                 if (tmp->type != RANGED_CALL)
 263                         continue;
 264                 if (!true_comparison_range_lr(comparison, tmp->range, value_range, left))
 265                         continue;
 266                 (tmp->u.ranged)(fn, expr, NULL, tmp->info);
 267         } END_FOR_EACH_PTR(tmp);
 268         tmp_slist = __pop_fake_cur_slist();
 269         merge_slist(&true_states, tmp_slist);
 270         free_slist(&tmp_slist);
 271
 272         /* set false states */
 273         __push_fake_cur_slist();
 274         FOR_EACH_PTR(call_backs, tmp) {
 275                 if (tmp->type != RANGED_CALL)
 276                         continue;
 277                 if (!false_comparison_range_lr(comparison, tmp->range, value_range, left))
 278                         continue;
 279                 (tmp->u.ranged)(fn, expr, NULL, tmp->info);
 280         } END_FOR_EACH_PTR(tmp);
 281         tmp_slist = __pop_fake_cur_slist();
 282         merge_slist(&false_states, tmp_slist);
 283         free_slist(&tmp_slist);
 284
 285         FOR_EACH_PTR(true_states, sm) {
 286                 __set_true_false_sm(sm, NULL);
 287         } END_FOR_EACH_PTR(sm);
 288         FOR_EACH_PTR(false_states, sm) {
 289                 __set_true_false_sm(NULL, sm);
 290         } END_FOR_EACH_PTR(sm);
 291
 292         free_slist(&true_states);
 293         free_slist(&false_states);
 294         return 1;
 295 }
 296
 297 struct db_callback_info {
 298         int true_side;
 299         int comparison;
 300         struct expression *expr;
 301         struct range_list *rl;
 302         int left;
 303         struct state_list *slist;
 304         struct db_implies_list *callbacks;
 305 };
 306 static struct db_callback_info db_info;
 307 static int db_compare_callback(void *unused, int argc, char **argv, char **azColName)
 308 {
 309         struct range_list *ret_range;
 310         int type, param;
 311         char *key, *value;
 312         struct return_implies_callback *tmp;
 313
 314         if (argc != 5)
 315                 return 0;
 316
 317         get_value_ranges(argv[0], &ret_range);
 318         type = atoi(argv[1]);
 319         param = atoi(argv[2]);
 320         key = argv[3];
 321         value = argv[4];
 322
 323         if (db_info.true_side) {
 324                 if (!possibly_true_range_lists_rl(db_info.comparison,
 325                                                   ret_range, db_info.rl,
 326                                                   db_info.left))
 327                         return 0;
 328         } else {
 329                 if (!possibly_false_range_lists_rl(db_info.comparison,
 330                                                   ret_range, db_info.rl,
 331                                                   db_info.left))
 332                         return 0;
 333         }
 334
 335         FOR_EACH_PTR(db_info.callbacks, tmp) {
 336                 if (tmp->type == type)
 337                         tmp->callback(db_info.expr, param, key, value);
 338         } END_FOR_EACH_PTR(tmp);
 339         return 0;
 340 }
 341
 342 void compare_db_implies_callbacks(int comparison, struct expression *expr, long long value, int left)
 343 {
 344         struct symbol *sym;
 345         static char sql_filter[1024];
 346         struct state_list *true_states;
 347         struct state_list *false_states;
 348         struct sm_state *sm;
 349
 350         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
 351                 return;
 352
 353         sym = expr->fn->symbol;
 354         if (!sym)
 355                 return;
 356
 357         if (sym->ctype.modifiers & MOD_STATIC) {
 358                 snprintf(sql_filter, 1024,
 359                          "file = '%s' and function = '%s' and static = '1';",
 360                          get_filename(), sym->ident->name);
 361         } else {
 362                 snprintf(sql_filter, 1024,
 363                          "function = '%s' and static = '0';", sym->ident->name);
 364         }
 365
 366         db_info.comparison = comparison;
 367         db_info.expr = expr;
 368         db_info.rl = alloc_range_list(value, value);
 369         db_info.left = left;
 370         db_info.callbacks = db_implies_list;
 371
 372         db_info.true_side = 1;
 373         __push_fake_cur_slist();
 374         run_sql(db_compare_callback,
 375                 "select return, type, parameter, key, value from return_implies where %s",
 376                 sql_filter);
 377         true_states = __pop_fake_cur_slist();
 378
 379         db_info.true_side = 0;
 380         __push_fake_cur_slist();
 381         run_sql(db_compare_callback,
 382                 "select return, type, parameter, key, value from return_implies where %s",
 383                 sql_filter);
 384         false_states = __pop_fake_cur_slist();
 385
 386         FOR_EACH_PTR(true_states, sm) {
 387                 __set_true_false_sm(sm, NULL);
 388         } END_FOR_EACH_PTR(sm);
 389         FOR_EACH_PTR(false_states, sm) {
 390                 __set_true_false_sm(NULL, sm);
 391         } END_FOR_EACH_PTR(sm);
 392
 393         free_slist(&true_states);
 394         free_slist(&false_states);
 395 }
 396
 397 void compare_db_return_states_callbacks(int comparison, struct expression *expr, long long value, int left)
 398 {
 399         struct symbol *sym;
 400         static char sql_filter[1024];
 401         struct state_list *true_states;
 402         struct state_list *false_states;
 403         struct sm_state *sm;
 404
 405         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
 406                 return;
 407
 408         sym = expr->fn->symbol;
 409         if (!sym)
 410                 return;
 411
 412         if (sym->ctype.modifiers & MOD_STATIC) {
 413                 snprintf(sql_filter, 1024,
 414                          "file = '%s' and function = '%s' and static = '1';",
 415                          get_filename(), sym->ident->name);
 416         } else {
 417                 snprintf(sql_filter, 1024,
 418                          "function = '%s' and static = '0';", sym->ident->name);
 419         }
 420
 421         db_info.comparison = comparison;
 422         db_info.expr = expr;
 423         db_info.rl = alloc_range_list(value, value);
 424         db_info.left = left;
 425         db_info.callbacks = db_return_states_list;
 426
 427         db_info.true_side = 1;
 428         __push_fake_cur_slist();
 429         run_sql(db_compare_callback,
 430                 "select return, type, parameter, key, value from return_states where %s",
 431                 sql_filter);
 432         true_states = __pop_fake_cur_slist();
 433
 434         db_info.true_side = 0;
 435         __push_fake_cur_slist();
 436         run_sql(db_compare_callback,
 437                 "select return, type, parameter, key, value from return_states where %s",
 438                 sql_filter);
 439         false_states = __pop_fake_cur_slist();
 440
 441         FOR_EACH_PTR(true_states, sm) {
 442                 __set_true_false_sm(sm, NULL);
 443         } END_FOR_EACH_PTR(sm);
 444         FOR_EACH_PTR(false_states, sm) {
 445                 __set_true_false_sm(NULL, sm);
 446         } END_FOR_EACH_PTR(sm);
 447
 448         free_slist(&true_states);
 449         free_slist(&false_states);
 450 }
 451
 452
 453
 454 void function_comparison(int comparison, struct expression *expr,
 455                                 long long value, int left)
 456 {
 457         if (call_implies_callbacks(comparison, expr, value, left))
 458                 return;
 459         compare_db_implies_callbacks(comparison, expr, value, left);
 460         compare_db_return_states_callbacks(comparison, expr, value, left);
 461 }
 462
 463 static int db_assign_callback(void *unused, int argc, char **argv, char **azColName)
 464 {
 465         struct range_list *ret_range;
 466         int type, param;
 467         char *key, *value;
 468         struct return_implies_callback *tmp;
 469         struct state_list *slist;
 470
 471         if (argc != 5)
 472                 return 0;
 473
 474         get_value_ranges(argv[0], &ret_range);
 475         type = atoi(argv[1]);
 476         param = atoi(argv[2]);
 477         key = argv[3];
 478         value = argv[4];
 479
 480         __push_fake_cur_slist();
 481         FOR_EACH_PTR(db_implies_list, tmp) {
 482                 if (tmp->type == type)
 483                         tmp->callback(db_info.expr->right, param, key, value);
 484         } END_FOR_EACH_PTR(tmp);
 485         set_extra_expr_mod(db_info.expr->left, alloc_estate_range_list(ret_range));
 486         slist = __pop_fake_cur_slist();
 487
 488         merge_slist(&db_info.slist, slist);
 489
 490         return 0;
 491 }
 492
 493 static int db_return_implies_assign(struct expression *expr)
 494 {
 495         struct symbol *sym;
 496         static char sql_filter[1024];
 497         static struct sm_state *sm;
 498         int handled = 0;
 499
 500         if (expr->right->fn->type != EXPR_SYMBOL || !expr->right->fn->symbol)
 501                 return 0;
 502
 503         sym = expr->right->fn->symbol;
 504         if (!sym)
 505                 return 0;
 506
 507         if (sym->ctype.modifiers & MOD_STATIC) {
 508                 snprintf(sql_filter, 1024,
 509                          "file = '%s' and function = '%s' and static = '1';",
 510                          get_filename(), sym->ident->name);
 511         } else {
 512                 snprintf(sql_filter, 1024,
 513                          "function = '%s' and static = '0';", sym->ident->name);
 514         }
 515
 516         db_info.expr = expr;
 517         db_info.slist = NULL;
 518         run_sql(db_assign_callback,
 519                 "select return, type, parameter, key, value from return_implies where %s",
 520                 sql_filter);
 521
 522         FOR_EACH_PTR(db_info.slist, sm) {
 523                 __set_sm(sm);
 524                 handled = 1;
 525         } END_FOR_EACH_PTR(sm);
 526
 527         return handled;
 528 }
 529
 530 static int prev_return_id;
 531 static int db_assign_return_states_callback(void *unused, int argc, char **argv, char **azColName)
 532 {
 533         struct range_list *ret_range;
 534         int type, param;
 535         char *key, *value;
 536         struct return_implies_callback *tmp;
 537         struct state_list *slist;
 538         int return_id;
 539
 540         if (argc != 6)
 541                 return 0;
 542
 543         return_id = atoi(argv[0]);
 544         get_value_ranges(argv[1], &ret_range);
 545         if (!ret_range)
 546                 ret_range = whole_range_list();
 547         type = atoi(argv[2]);
 548         param = atoi(argv[3]);
 549         key = argv[4];
 550         value = argv[5];
 551
 552         if (prev_return_id != -1 && return_id != prev_return_id) {
 553                 slist = __pop_fake_cur_slist();
 554                 merge_slist(&db_info.slist, slist);
 555                 __push_fake_cur_slist();
 556         }
 557         prev_return_id = return_id;
 558
 559         FOR_EACH_PTR(db_return_states_list, tmp) {
 560                 if (tmp->type == type)
 561                         tmp->callback(db_info.expr, param, key, value);
 562         } END_FOR_EACH_PTR(tmp);
 563         set_extra_expr_mod(db_info.expr->left, alloc_estate_range_list(ret_range));
 564
 565         return 0;
 566 }
 567
 568 static int db_return_states_assign(struct expression *expr)
 569 {
 570         struct expression *right;
 571         struct symbol *sym;
 572         struct sm_state *sm;
 573         struct state_list *slist;
 574         static char sql_filter[1024];
 575         int handled = 0;
 576
 577         right = strip_expr(expr->right);
 578         if (right->fn->type != EXPR_SYMBOL || !right->fn->symbol)
 579                 return 0;
 580
 581         sym = right->fn->symbol;
 582         if (!sym)
 583                 return 0;
 584
 585         if (sym->ctype.modifiers & MOD_STATIC) {
 586                 snprintf(sql_filter, 1024,
 587                          "file = '%s' and function = '%s' and static = '1';",
 588                          get_filename(), sym->ident->name);
 589         } else {
 590                 snprintf(sql_filter, 1024,
 591                          "function = '%s' and static = '0';", sym->ident->name);
 592         }
 593
 594         prev_return_id = -1;
 595         db_info.expr = expr;
 596         db_info.slist = NULL;
 597         __push_fake_cur_slist();
 598         run_sql(db_assign_return_states_callback,
 599                 "select return_id, return, type, parameter, key, value from return_states where %s",
 600                 sql_filter);
 601         slist = __pop_fake_cur_slist();
 602         merge_slist(&db_info.slist, slist);
 603
 604         FOR_EACH_PTR(db_info.slist, sm) {
 605                 __set_sm(sm);
 606                 handled = 1;
 607         } END_FOR_EACH_PTR(sm);
 608
 609         return handled;
 610 }
 611
 612 static int handle_implied_return(struct expression *expr)
 613 {
 614         struct range_list *rl;
 615
 616         if (!get_implied_return(expr->right, &rl))
 617                 return 0;
 618         set_extra_expr_mod(expr->left, alloc_estate_range_list(rl));
 619         return 1;
 620 }
 621
 622 static void match_assign_call(struct expression *expr)
 623 {
 624         struct call_back_list *call_backs;
 625         const char *fn;
 626         struct expression *right;
 627         int handled = 0;
 628
 629         right = strip_expr(expr->right);
 630         if (right->fn->type != EXPR_SYMBOL || !right->fn->symbol) {
 631                 set_extra_expr_mod(expr->left, extra_undefined());
 632                 return;
 633         }
 634         fn = right->fn->symbol->ident->name;
 635
 636         /*
 637          * some of these conflict (they try to set smatch extra twice), so we
 638          * call them in order from least important to most important.
 639          */
 640
 641         call_backs = search_callback(func_hash, (char *)fn);
 642         call_call_backs(call_backs, ASSIGN_CALL, fn, expr);
 643
 644         handled |= db_return_states_assign(expr);
 645         handled |= db_return_implies_assign(expr);
 646         handled |= assign_ranged_funcs(fn, expr, call_backs);
 647         handled |= handle_implied_return(expr);
 648
 649         if (!handled)
 650                 set_extra_expr_mod(expr->left, extra_undefined());
 651 }
 652
 653 static int db_return_states_callback(void *unused, int argc, char **argv, char **azColName)
 654 {
 655         struct range_list *ret_range;
 656         int type, param;
 657         char *key, *value;
 658         struct return_implies_callback *tmp;
 659         struct state_list *slist;
 660         int return_id;
 661
 662         if (argc != 6)
 663                 return 0;
 664
 665         return_id = atoi(argv[0]);
 666         get_value_ranges(argv[1], &ret_range);
 667         type = atoi(argv[2]);
 668         param = atoi(argv[3]);
 669         key = argv[4];
 670         value = argv[5];
 671
 672         if (prev_return_id != -1 && return_id != prev_return_id) {
 673                 slist = __pop_fake_cur_slist();
 674                 merge_slist(&db_info.slist, slist);
 675                 __push_fake_cur_slist();
 676         }
 677         prev_return_id = return_id;
 678
 679         FOR_EACH_PTR(db_return_states_list, tmp) {
 680                 if (tmp->type == type)
 681                         tmp->callback(db_info.expr, param, key, value);
 682         } END_FOR_EACH_PTR(tmp);
 683
 684         return 0;
 685 }
 686
 687 static void db_return_states(struct expression *expr)
 688 {
 689         struct symbol *sym;
 690         struct sm_state *sm;
 691         struct state_list *slist;
 692         static char sql_filter[1024];
 693
 694         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
 695                 return;
 696
 697         sym = expr->fn->symbol;
 698         if (!sym)
 699                 return;
 700
 701         if (sym->ctype.modifiers & MOD_STATIC) {
 702                 snprintf(sql_filter, 1024,
 703                          "file = '%s' and function = '%s' and static = '1';",
 704                          get_filename(), sym->ident->name);
 705         } else {
 706                 snprintf(sql_filter, 1024,
 707                          "function = '%s' and static = '0';", sym->ident->name);
 708         }
 709
 710         prev_return_id = -1;
 711         db_info.expr = expr;
 712         db_info.slist = NULL;
 713         __push_fake_cur_slist();
 714         run_sql(db_return_states_callback,
 715                 "select return_id, return, type, parameter, key, value from return_states where %s",
 716                 sql_filter);
 717         slist = __pop_fake_cur_slist();
 718         merge_slist(&db_info.slist, slist);
 719
 720         FOR_EACH_PTR(db_info.slist, sm) {
 721                 __set_sm(sm);
 722         } END_FOR_EACH_PTR(sm);
 723 }
 724
 725 static int is_assigned_call(struct expression *expr)
 726 {
 727         struct expression *tmp;
 728
 729         FOR_EACH_PTR_REVERSE(big_expression_stack, tmp) {
 730                 if (tmp->type == EXPR_ASSIGNMENT && strip_expr(tmp->right) == expr)
 731                         return 1;
 732                 if (tmp->pos.line < expr->pos.line)
 733                         return 0;
 734         } END_FOR_EACH_PTR_REVERSE(tmp);
 735         return 0;
 736 }
 737
 738 static void db_return_states_call(struct expression *expr)
 739 {
 740         if (is_assigned_call(expr))
 741                 return;
 742         db_return_states(expr);
 743 }
 744
 745 static void match_function_call(struct expression *expr)
 746 {
 747         struct call_back_list *call_backs;
 748
 749         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
 750                 return;
 751         call_backs = search_callback(func_hash, (char *)expr->fn->symbol->ident->name);
 752         if (call_backs)
 753                 call_call_backs(call_backs, REGULAR_CALL,
 754                                 expr->fn->symbol->ident->name, expr);
 755         db_return_states_call(expr);
 756 }
 757
 758 static void match_macro_assign(struct expression *expr)
 759 {
 760         struct call_back_list *call_backs;
 761         const char *macro;
 762         struct expression *right;
 763
 764         right = strip_expr(expr->right);
 765         macro = get_macro_name(right->pos);
 766         call_backs = search_callback(func_hash, (char *)macro);
 767         if (!call_backs)
 768                 return;
 769         call_call_backs(call_backs, MACRO_ASSIGN, macro, expr);
 770         call_call_backs(call_backs, MACRO_ASSIGN_EXTRA, macro, expr);
 771 }
 772
 773 int get_implied_return(struct expression *expr, struct range_list **rl)
 774 {
 775         struct call_back_list *call_backs;
 776         struct fcall_back *tmp;
 777         int handled = 0;
 778         char *fn;
 779
 780         *rl = NULL;
 781
 782         expr = strip_expr(expr);
 783         fn = get_variable_from_expr(expr->fn, NULL);
 784         if (!fn)
 785                 goto out;
 786
 787         call_backs = search_callback(func_hash, fn);
 788
 789         FOR_EACH_PTR(call_backs, tmp) {
 790                 if (tmp->type == IMPLIED_RETURN) {
 791                         (tmp->u.implied_return)(expr, tmp->info, rl);
 792                         handled = 1;
 793                 }
 794         } END_FOR_EACH_PTR(tmp);
 795
 796 out:
 797         free_string(fn);
 798         return handled;
 799 }
 800
 801 void create_function_hook_hash(void)
 802 {
 803         func_hash = create_function_hashtable(5000);
 804 }
 805
 806 void register_function_hooks(int id)
 807 {
 808         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
 809         add_hook(&match_assign_call, CALL_ASSIGNMENT_HOOK);
 810         add_hook(&match_macro_assign, MACRO_ASSIGNMENT_HOOK);
 811 }