smatch_function_hooks.c

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