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