smatch_conditions.c

   1 /*
   2  * Copyright (C) 2006,2008 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  * The simplest type of condition is
  20  * if (a) { ...
  21  *
  22  * The next simplest kind of conditions is
  23  * if (a && b) { c;
  24  * In that case 'a' is true when we get to 'b' and both are true
  25  * when we get to c.
  26  *
  27  * Or's are a little more complicated.
  28  * if (a || b) { c;
  29  * We know 'a' is not true when we get to 'b' but it may be true
  30  * when we get to c.
  31  *
  32  * If we mix and's and or's that's even more complicated.
  33  * if (a && b && c || a && d) { d ;
  34  * 'a' is true when we evaluate 'b', and 'd'.
  35  * 'b' is true when we evaluate 'c' but otherwise we don't.
  36  *
  37  * The other thing that complicates matters is if we negate
  38  * some if conditions.
  39  * if (!a) { ...
  40  * Smatch has passes the un-negated version to the client and flip
  41  * the true and false values internally.  This makes it easier
  42  * to write checks.
  43  *
  44  * And negations can be part of a compound.
  45  * if (a && !(b || c)) { d;
  46  * In that situation we multiply the negative through to simplify
  47  * stuff so that we can remove the parens like this:
  48  * if (a && !b && !c) { d;
  49  *
  50  * One other thing is that:
  51  * if ((a) != 0){ ...
  52  * that's basically the same as testing for just 'a' and we simplify
  53  * comparisons with zero before passing it to the script.
  54  *
  55  */
  56
  57 #include "smatch.h"
  58 #include "smatch_slist.h"
  59 #include "smatch_extra.h"
  60 #include "smatch_expression_stacks.h"
  61
  62 extern int __expr_stmt_count;
  63
  64 struct expression_list *big_condition_stack;
  65
  66 static void split_conditions(struct expression *expr);
  67
  68 static int is_logical_and(struct expression *expr)
  69 {
  70         if (expr->op == SPECIAL_LOGICAL_AND)
  71                 return 1;
  72         return 0;
  73 }
  74
  75 static int handle_zero_comparisons(struct expression *expr)
  76 {
  77         struct expression *tmp = NULL;
  78
  79         // if left is zero or right is zero
  80         if (is_zero(expr->left))
  81                 tmp = expr->right;
  82         else if (is_zero(expr->right))
  83                 tmp = expr->left;
  84         else
  85                 return 0;
  86
  87         // "if (foo != 0)" is the same as "if (foo)"
  88         if (expr->op == SPECIAL_NOTEQUAL) {
  89                 split_conditions(tmp);
  90                 return 1;
  91         }
  92
  93         // "if (foo == 0)" is the same as "if (!foo)"
  94         if (expr->op == SPECIAL_EQUAL) {
  95                 split_conditions(tmp);
  96                 __negate_cond_stacks();
  97                 return 1;
  98         }
  99
 100         return 0;
 101 }
 102
 103 /*
 104  * This function is for handling calls to likely/unlikely
 105  */
 106
 107 static int ignore_builtin_expect(struct expression *expr)
 108 {
 109         if (sym_name_is("__builtin_expect", expr->fn)) {
 110                 split_conditions(first_ptr_list((struct ptr_list *) expr->args));
 111                 return 1;
 112         }
 113         return 0;
 114 }
 115
 116 /*
 117  * handle_compound_stmt() is for: foo = ({blah; blah; blah; 1})
 118  */
 119
 120 static void handle_compound_stmt(struct statement *stmt)
 121 {
 122         struct expression *expr = NULL;
 123         struct statement *last;
 124         struct statement *s;
 125
 126         last = last_ptr_list((struct ptr_list *)stmt->stmts);
 127         if (last->type == STMT_LABEL) {
 128                 if (last->label_statement &&
 129                     last->label_statement->type == STMT_EXPRESSION)
 130                         expr = last->label_statement->expression;
 131                 else
 132                         last = NULL;
 133         } else if (last->type != STMT_EXPRESSION) {
 134                 last = NULL;
 135         } else {
 136                 expr = last->expression;
 137         }
 138
 139         FOR_EACH_PTR(stmt->stmts, s) {
 140                 if (s != last)
 141                         __split_stmt(s);
 142         } END_FOR_EACH_PTR(s);
 143         if (last && last->type == STMT_LABEL)
 144                 __split_label_stmt(last);
 145         split_conditions(expr);
 146 }
 147
 148 static int handle_preop(struct expression *expr)
 149 {
 150         struct statement *stmt;
 151
 152         if (expr->op == '!') {
 153                 split_conditions(expr->unop);
 154                 __negate_cond_stacks();
 155                 return 1;
 156         }
 157         stmt = get_expression_statement(expr);
 158         if (stmt) {
 159                 handle_compound_stmt(stmt);
 160                 return 1;
 161         }
 162         return 0;
 163 }
 164
 165 static void handle_logical(struct expression *expr)
 166 {
 167         /*
 168          * If we come to an "and" expr then:
 169          * We split the left side.
 170          * We keep all the current states.
 171          * We split the right side.
 172          * We keep all the states from both true sides.
 173          *
 174          * If it's an "or" expr then:
 175          * We save the current slist.
 176          * We split the left side.
 177          * We use the false states for the right side.
 178          * We split the right side.
 179          * We save all the states that are the same on both sides.
 180          */
 181
 182         split_conditions(expr->left);
 183
 184         if (is_logical_and(expr))
 185                 __use_cond_true_states();
 186         else
 187                 __use_cond_false_states();
 188
 189         __push_cond_stacks();
 190
 191         __save_pre_cond_states();
 192         split_conditions(expr->right);
 193         __discard_pre_cond_states();
 194
 195         if (is_logical_and(expr))
 196                 __and_cond_states();
 197         else
 198                 __or_cond_states();
 199
 200         __use_cond_true_states();
 201 }
 202
 203 static struct stree *combine_strees(struct stree *orig, struct stree *fake, struct stree *new)
 204 {
 205         struct stree *ret = NULL;
 206
 207         overwrite_stree(orig, &ret);
 208         overwrite_stree(fake, &ret);
 209         overwrite_stree(new, &ret);
 210         free_stree(&new);
 211
 212         return ret;
 213 }
 214
 215 /*
 216  * handle_select()
 217  * if ((aaa()?bbb():ccc())) { ...
 218  *
 219  * This is almost the same as:
 220  * if ((aaa() && bbb()) || (!aaa() && ccc())) { ...
 221  *
 222  * It's a bit complicated because we shouldn't pass aaa()
 223  * to the clients more than once.
 224  */
 225
 226 static void handle_select(struct expression *expr)
 227 {
 228         struct stree *a_T = NULL;
 229         struct stree *a_F = NULL;
 230         struct stree *a_T_b_T = NULL;
 231         struct stree *a_T_b_F = NULL;
 232         struct stree *a_T_b_fake = NULL;
 233         struct stree *a_F_c_T = NULL;
 234         struct stree *a_F_c_F = NULL;
 235         struct stree *a_F_c_fake = NULL;
 236         struct stree *tmp;
 237         struct sm_state *sm;
 238
 239         /*
 240          * Imagine we have this:  if (a ? b : c) { ...
 241          *
 242          * The condition is true if "a" is true and "b" is true or
 243          * "a" is false and "c" is true.  It's false if "a" is true
 244          * and "b" is false or "a" is false and "c" is false.
 245          *
 246          * The variable name "a_T_b_T" stands for "a true b true" etc.
 247          *
 248          * But if we know "b" is true then we can simpilify things.
 249          * The condition is true if "a" is true or if "a" is false and
 250          * "c" is true.  The only way the condition can be false is if
 251          * "a" is false and "c" is false.
 252          *
 253          * The remaining thing is the "a_T_b_fake".  When we simplify
 254          * the equations we have to take into consideration that other
 255          * states may have changed that don't play into the true false
 256          * equation.  Take the following example:
 257          * if ({
 258          *         (flags) = __raw_local_irq_save();
 259          *         _spin_trylock(lock) ? 1 :
 260          *                 ({ raw_local_irq_restore(flags);  0; });
 261          *    })
 262          * Smatch has to record that the irq flags were restored on the
 263          * false path.
 264          *
 265          */
 266
 267         __save_pre_cond_states();
 268
 269         split_conditions(expr->conditional);
 270
 271         a_T = __copy_cond_true_states();
 272         a_F = __copy_cond_false_states();
 273
 274         __use_cond_true_states();
 275
 276         __push_cond_stacks();
 277         __push_fake_cur_stree();
 278         split_conditions(expr->cond_true);
 279         __process_post_op_stack();
 280         a_T_b_fake = __pop_fake_cur_stree();
 281         a_T_b_T = combine_strees(a_T, a_T_b_fake, __pop_cond_true_stack());
 282         a_T_b_F = combine_strees(a_T, a_T_b_fake, __pop_cond_false_stack());
 283
 284         __use_cond_false_states();
 285
 286         __push_cond_stacks();
 287         __push_fake_cur_stree();
 288         split_conditions(expr->cond_false);
 289         a_F_c_fake = __pop_fake_cur_stree();
 290         a_F_c_T = combine_strees(a_F, a_F_c_fake, __pop_cond_true_stack());
 291         a_F_c_F = combine_strees(a_F, a_F_c_fake, __pop_cond_false_stack());
 292
 293         /* We have to restore the pre condition states so that
 294            implied_condition_true() will use the right cur_stree */
 295         __use_pre_cond_states();
 296
 297         if (implied_condition_true(expr->cond_true)) {
 298                 free_stree(&a_T_b_T);
 299                 free_stree(&a_T_b_F);
 300                 a_T_b_T = clone_stree(a_T);
 301                 overwrite_stree(a_T_b_fake, &a_T_b_T);
 302         }
 303         if (implied_condition_false(expr->cond_true)) {
 304                 free_stree(&a_T_b_T);
 305                 free_stree(&a_T_b_F);
 306                 a_T_b_F = clone_stree(a_T);
 307                 overwrite_stree(a_T_b_fake, &a_T_b_F);
 308         }
 309         if (implied_condition_true(expr->cond_false)) {
 310                 free_stree(&a_F_c_T);
 311                 free_stree(&a_F_c_F);
 312                 a_F_c_T = clone_stree(a_F);
 313                 overwrite_stree(a_F_c_fake, &a_F_c_T);
 314         }
 315         if (implied_condition_false(expr->cond_false)) {
 316                 free_stree(&a_F_c_T);
 317                 free_stree(&a_F_c_F);
 318                 a_F_c_F = clone_stree(a_F);
 319                 overwrite_stree(a_F_c_fake, &a_F_c_F);
 320         }
 321
 322         merge_stree(&a_T_b_T, a_F_c_T);
 323         merge_stree(&a_T_b_F, a_F_c_F);
 324
 325         tmp = __pop_cond_true_stack();
 326         free_stree(&tmp);
 327         tmp = __pop_cond_false_stack();
 328         free_stree(&tmp);
 329
 330         __push_cond_stacks();
 331         FOR_EACH_SM(a_T_b_T, sm) {
 332                 __set_true_false_sm(sm, NULL);
 333         } END_FOR_EACH_SM(sm);
 334         FOR_EACH_SM(a_T_b_F, sm) {
 335                 __set_true_false_sm(NULL, sm);
 336         } END_FOR_EACH_SM(sm);
 337         __free_set_states();
 338
 339         free_stree(&a_T_b_fake);
 340         free_stree(&a_F_c_fake);
 341         free_stree(&a_F_c_T);
 342         free_stree(&a_F_c_F);
 343         free_stree(&a_T_b_T);
 344         free_stree(&a_T_b_F);
 345         free_stree(&a_T);
 346         free_stree(&a_F);
 347 }
 348
 349 static void handle_comma(struct expression *expr)
 350 {
 351         set_parent_expr(expr->left, expr);
 352         set_parent_expr(expr->right, expr);
 353         __split_expr(expr->left);
 354         split_conditions(expr->right);
 355 }
 356
 357 static int make_op_unsigned(int op)
 358 {
 359         switch (op) {
 360         case '<':
 361                 return SPECIAL_UNSIGNED_LT;
 362         case SPECIAL_LTE:
 363                 return SPECIAL_UNSIGNED_LTE;
 364         case '>':
 365                 return SPECIAL_UNSIGNED_GT;
 366         case SPECIAL_GTE:
 367                 return SPECIAL_UNSIGNED_GTE;
 368         }
 369         return op;
 370 }
 371
 372 static void hackup_unsigned_compares(struct expression *expr)
 373 {
 374         if (expr->type != EXPR_COMPARE)
 375                 return;
 376
 377         if (type_unsigned(get_type(expr)))
 378                 expr->op = make_op_unsigned(expr->op);
 379 }
 380
 381 static void do_condition(struct expression *expr)
 382 {
 383         __fold_in_set_states();
 384         __push_fake_cur_stree();
 385         __pass_to_client(expr, CONDITION_HOOK);
 386         __fold_in_set_states();
 387 }
 388
 389 static void split_conditions(struct expression *expr)
 390 {
 391         if (option_debug) {
 392                 char *cond = expr_to_str(expr);
 393
 394                 sm_msg("%d in split_conditions (%s)", get_lineno(), cond);
 395                 free_string(cond);
 396         }
 397
 398         expr = strip_expr(expr);
 399         if (!expr) {
 400                 __fold_in_set_states();
 401                 return;
 402         }
 403
 404         switch (expr->type) {
 405         case EXPR_LOGICAL:
 406                 __pass_to_client(expr, LOGIC_HOOK);
 407                 handle_logical(expr);
 408                 return;
 409         case EXPR_COMPARE:
 410                 hackup_unsigned_compares(expr);
 411                 if (handle_zero_comparisons(expr))
 412                         return;
 413                 break;
 414         case EXPR_CALL:
 415                 if (ignore_builtin_expect(expr))
 416                         return;
 417                 break;
 418         case EXPR_PREOP:
 419                 if (handle_preop(expr))
 420                         return;
 421                 break;
 422         case EXPR_CONDITIONAL:
 423         case EXPR_SELECT:
 424                 handle_select(expr);
 425                 return;
 426         case EXPR_COMMA:
 427                 handle_comma(expr);
 428                 return;
 429         }
 430
 431         /* fixme: this should be in smatch_flow.c
 432            but because of the funny stuff we do with conditions
 433            it's awkward to put it there.  We would need to
 434            call CONDITION_HOOK in smatch_flow as well.
 435         */
 436         push_expression(&big_expression_stack, expr);
 437         push_expression(&big_condition_stack, expr);
 438
 439         if (expr->type == EXPR_COMPARE) {
 440                 set_parent_expr(expr->left, expr);
 441                 set_parent_expr(expr->right, expr);
 442
 443                 if (expr->left->type != EXPR_POSTOP)
 444                         __split_expr(expr->left);
 445                 if (expr->right->type != EXPR_POSTOP)
 446                         __split_expr(expr->right);
 447         } else if (expr->type != EXPR_POSTOP) {
 448                 __split_expr(expr);
 449         }
 450         do_condition(expr);
 451         if (expr->type == EXPR_COMPARE) {
 452                 if (expr->left->type == EXPR_POSTOP)
 453                         __split_expr(expr->left);
 454                 if (expr->right->type == EXPR_POSTOP)
 455                         __split_expr(expr->right);
 456         } else if (expr->type == EXPR_POSTOP) {
 457                 __split_expr(expr);
 458         }
 459         __push_fake_cur_stree();
 460         __process_post_op_stack();
 461         __fold_in_set_states();
 462         pop_expression(&big_condition_stack);
 463         pop_expression(&big_expression_stack);
 464 }
 465
 466 static int inside_condition;
 467 void __split_whole_condition(struct expression *expr)
 468 {
 469         sm_debug("%d in __split_whole_condition\n", get_lineno());
 470         inside_condition++;
 471         __save_pre_cond_states();
 472         __push_cond_stacks();
 473         /* it's a hack, but it's sometimes handy to have this stuff
 474            on the big_expression_stack.  */
 475         push_expression(&big_expression_stack, expr);
 476         split_conditions(expr);
 477         __use_cond_states();
 478         __pass_to_client(expr, WHOLE_CONDITION_HOOK);
 479         pop_expression(&big_expression_stack);
 480         inside_condition--;
 481         sm_debug("%d done __split_whole_condition\n", get_lineno());
 482 }
 483
 484 void __handle_logic(struct expression *expr)
 485 {
 486         sm_debug("%d in __handle_logic\n", get_lineno());
 487         inside_condition++;
 488         __save_pre_cond_states();
 489         __push_cond_stacks();
 490         /* it's a hack, but it's sometimes handy to have this stuff
 491            on the big_expression_stack.  */
 492         push_expression(&big_expression_stack, expr);
 493         if (expr)
 494                 split_conditions(expr);
 495         __use_cond_states();
 496         __pass_to_client(expr, WHOLE_CONDITION_HOOK);
 497         pop_expression(&big_expression_stack);
 498         __merge_false_states();
 499         inside_condition--;
 500         sm_debug("%d done __handle_logic\n", get_lineno());
 501 }
 502
 503 int is_condition(struct expression *expr)
 504 {
 505
 506         expr = strip_expr(expr);
 507         if (!expr)
 508                 return 0;
 509
 510         switch (expr->type) {
 511         case EXPR_LOGICAL:
 512         case EXPR_COMPARE:
 513                 return 1;
 514         case EXPR_PREOP:
 515                 if (expr->op == '!')
 516                         return 1;
 517         }
 518         return 0;
 519 }
 520
 521 int __handle_condition_assigns(struct expression *expr)
 522 {
 523         struct expression *right;
 524         struct stree *true_stree, *false_stree, *fake_stree;
 525         struct sm_state *sm;
 526
 527         if (expr->op != '=')
 528                 return 0;
 529         right = strip_expr(expr->right);
 530         if (!is_condition(expr->right))
 531                 return 0;
 532
 533         sm_debug("%d in __handle_condition_assigns\n", get_lineno());
 534         inside_condition++;
 535         __save_pre_cond_states();
 536         __push_cond_stacks();
 537         /* it's a hack, but it's sometimes handy to have this stuff
 538            on the big_expression_stack.  */
 539         push_expression(&big_expression_stack, right);
 540         split_conditions(right);
 541         true_stree = __get_true_states();
 542         false_stree = __get_false_states();
 543         __use_cond_states();
 544         __push_fake_cur_stree();
 545         set_extra_expr_mod(expr->left, alloc_estate_sval(sval_type_val(get_type(expr->left), 1)));
 546         __pass_to_client(right, WHOLE_CONDITION_HOOK);
 547
 548         fake_stree = __pop_fake_cur_stree();
 549         FOR_EACH_SM(fake_stree, sm) {
 550                 overwrite_sm_state_stree(&true_stree, sm);
 551         } END_FOR_EACH_SM(sm);
 552         free_stree(&fake_stree);
 553
 554         pop_expression(&big_expression_stack);
 555         inside_condition--;
 556
 557         __push_true_states();
 558
 559         __use_false_states();
 560         __push_fake_cur_stree();
 561         set_extra_expr_mod(expr->left, alloc_estate_sval(sval_type_val(get_type(expr->left), 0)));
 562
 563         fake_stree = __pop_fake_cur_stree();
 564         FOR_EACH_SM(fake_stree, sm) {
 565                 overwrite_sm_state_stree(&false_stree, sm);
 566         } END_FOR_EACH_SM(sm);
 567         free_stree(&fake_stree);
 568
 569         __merge_true_states();
 570         merge_fake_stree(&true_stree, false_stree);
 571         free_stree(&false_stree);
 572         FOR_EACH_SM(true_stree, sm) {
 573                 __set_sm(sm);
 574         } END_FOR_EACH_SM(sm);
 575
 576         __pass_to_client(expr, ASSIGNMENT_HOOK);
 577         sm_debug("%d done __handle_condition_assigns\n", get_lineno());
 578         return 1;
 579 }
 580
 581 static int is_select_assign(struct expression *expr)
 582 {
 583         struct expression *right;
 584
 585         if (expr->op != '=')
 586                 return 0;
 587         right = strip_expr(expr->right);
 588         if (right->type == EXPR_CONDITIONAL)
 589                 return 1;
 590         if (right->type == EXPR_SELECT)
 591                 return 1;
 592         return 0;
 593 }
 594
 595 static void set_fake_assign(struct expression *new,
 596                         struct expression *left, int op, struct expression *right)
 597 {
 598
 599         new->pos = left->pos;
 600         new->op = op;
 601         new->type = EXPR_ASSIGNMENT;
 602         new->left = left;
 603         new->right = right;
 604 }
 605
 606 int __handle_select_assigns(struct expression *expr)
 607 {
 608         struct expression *right;
 609         struct stree *final_states = NULL;
 610         struct sm_state *sm;
 611         int is_true;
 612         int is_false;
 613
 614         if (!is_select_assign(expr))
 615                 return 0;
 616         sm_debug("%d in __handle_ternary_assigns\n", get_lineno());
 617         right = strip_expr(expr->right);
 618
 619         is_true = implied_condition_true(right->conditional);
 620         is_false = implied_condition_false(right->conditional);
 621
 622         /* hah hah.  the ultra fake out */
 623         __save_pre_cond_states();
 624         __split_whole_condition(right->conditional);
 625
 626         if (!is_false) {
 627                 struct expression fake_expr;
 628
 629                 if (right->cond_true)
 630                         set_fake_assign(&fake_expr, expr->left, expr->op, right->cond_true);
 631                 else
 632                         set_fake_assign(&fake_expr, expr->left, expr->op, right->conditional);
 633                 __split_expr(&fake_expr);
 634                 final_states = clone_stree(__get_cur_stree());
 635         }
 636
 637         __use_false_states();
 638         if (!is_true) {
 639                 struct expression fake_expr;
 640
 641                 set_fake_assign(&fake_expr, expr->left, expr->op, right->cond_false);
 642                 __split_expr(&fake_expr);
 643                 merge_stree(&final_states, __get_cur_stree());
 644         }
 645
 646         __use_pre_cond_states();
 647
 648         FOR_EACH_SM(final_states, sm) {
 649                 __set_sm(sm);
 650         } END_FOR_EACH_SM(sm);
 651
 652         free_stree(&final_states);
 653
 654         sm_debug("%d done __handle_ternary_assigns\n", get_lineno());
 655
 656         return 1;
 657 }
 658
 659 static struct statement *split_then_return_last(struct statement *stmt)
 660 {
 661         struct statement *tmp;
 662         struct statement *last_stmt;
 663
 664         last_stmt = last_ptr_list((struct ptr_list *)stmt->stmts);
 665         if (!last_stmt)
 666                 return NULL;
 667
 668         __push_scope_hooks();
 669         FOR_EACH_PTR(stmt->stmts, tmp) {
 670                 if (tmp == last_stmt) {
 671                         if (tmp->type == STMT_LABEL) {
 672                                 __split_label_stmt(tmp);
 673                                 return stmt->label_statement;
 674                         }
 675                         return last_stmt;
 676                 }
 677                 __split_stmt(tmp);
 678         } END_FOR_EACH_PTR(tmp);
 679         return NULL;
 680 }
 681
 682 int __handle_expr_statement_assigns(struct expression *expr)
 683 {
 684         struct expression *right;
 685         struct statement *stmt;
 686
 687         right = expr->right;
 688         if (right->type == EXPR_PREOP && right->op == '(')
 689                 right = right->unop;
 690         if (right->type != EXPR_STATEMENT)
 691                 return 0;
 692
 693         __expr_stmt_count++;
 694         stmt = right->statement;
 695         if (stmt->type == STMT_COMPOUND) {
 696                 struct statement *last_stmt;
 697                 struct expression fake_assign;
 698                 struct expression fake_expr_stmt;
 699
 700                 last_stmt = split_then_return_last(stmt);
 701                 if (!last_stmt) {
 702                         __expr_stmt_count--;
 703                         return 0;
 704                 }
 705
 706                 fake_expr_stmt.pos = last_stmt->pos;
 707                 fake_expr_stmt.type = EXPR_STATEMENT;
 708                 fake_expr_stmt.statement = last_stmt;
 709
 710                 fake_assign.pos = last_stmt->pos;
 711                 fake_assign.op = expr->op;
 712                 fake_assign.type = EXPR_ASSIGNMENT;
 713                 fake_assign.left = expr->left;
 714                 fake_assign.right = &fake_expr_stmt;
 715
 716                 __split_expr(&fake_assign);
 717
 718                 __call_scope_hooks();
 719         } else if (stmt->type == STMT_EXPRESSION) {
 720                 struct expression fake_assign;
 721
 722                 fake_assign.pos = stmt->pos;
 723                 fake_assign.op = expr->op;
 724                 fake_assign.type = EXPR_ASSIGNMENT;
 725                 fake_assign.left = expr->left;
 726                 fake_assign.right = stmt->expression;
 727
 728                 __split_expr(&fake_assign);
 729
 730         } else {
 731                 __split_stmt(stmt);
 732         }
 733         __expr_stmt_count--;
 734         return 1;
 735 }
 736
 737 int in_condition(void)
 738 {
 739         return inside_condition;
 740 }