smatch_flow.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 #define _GNU_SOURCE 1
  19 #include <unistd.h>
  20 #include <stdio.h>
  21 #include "token.h"
  22 #include "scope.h"
  23 #include "smatch.h"
  24 #include "smatch_expression_stacks.h"
  25 #include "smatch_extra.h"
  26 #include "smatch_slist.h"
  27
  28 int __in_fake_assign;
  29 int final_pass;
  30 int __inline_call;
  31 struct expression  *__inline_fn;
  32
  33 static int __smatch_lineno = 0;
  34
  35 static char *base_file;
  36 static const char *filename;
  37 static char *pathname;
  38 static char *full_filename;
  39 static char *cur_func;
  40 static unsigned int loop_count;
  41 int __expr_stmt_count;
  42 int __in_function_def;
  43 static struct expression_list *switch_expr_stack = NULL;
  44 static struct expression_list *post_op_stack = NULL;
  45
  46 struct expression_list *big_expression_stack;
  47 struct statement_list *big_statement_stack;
  48 int __in_pre_condition = 0;
  49 int __bail_on_rest_of_function = 0;
  50 char *get_function(void) { return cur_func; }
  51 int get_lineno(void) { return __smatch_lineno; }
  52 int inside_loop(void) { return !!loop_count; }
  53 int definitely_inside_loop(void) { return !!(loop_count & ~0x80000000); }
  54 struct expression *get_switch_expr(void) { return top_expression(switch_expr_stack); }
  55 int in_expression_statement(void) { return !!__expr_stmt_count; }
  56
  57 static void split_symlist(struct symbol_list *sym_list);
  58 static void split_declaration(struct symbol_list *sym_list);
  59 static void split_expr_list(struct expression_list *expr_list);
  60 static void add_inline_function(struct symbol *sym);
  61 static void parse_inline(struct expression *expr);
  62
  63 int option_assume_loops = 0;
  64 int option_known_conditions = 0;
  65 int option_two_passes = 0;
  66 struct symbol *cur_func_sym = NULL;
  67
  68 int outside_of_function(void)
  69 {
  70         return cur_func_sym == NULL;
  71 }
  72
  73 const char *get_filename(void)
  74 {
  75         if (option_info)
  76                 return base_file;
  77         if (option_full_path)
  78                 return full_filename;
  79         return filename;
  80 }
  81
  82 const char *get_base_file(void)
  83 {
  84         return base_file;
  85 }
  86
  87 static void set_position(struct position pos)
  88 {
  89         int len;
  90         static int prev_stream = -1;
  91
  92         if (pos.stream == 0 && pos.line == 0)
  93                 return;
  94
  95         __smatch_lineno = pos.line;
  96
  97         if (pos.stream == prev_stream)
  98                 return;
  99
 100         filename = stream_name(pos.stream);
 101
 102         free(full_filename);
 103         pathname = getcwd(NULL, 0);
 104         if (pathname) {
 105                 len = strlen(pathname) + 1 + strlen(filename) + 1;
 106                 full_filename = malloc(len);
 107                 snprintf(full_filename, len, "%s/%s", pathname, filename);
 108         } else {
 109                 full_filename = alloc_string(filename);
 110         }
 111         free(pathname);
 112 }
 113
 114 static int is_inline_func(struct expression *expr)
 115 {
 116         if (expr->type != EXPR_SYMBOL || !expr->symbol)
 117                 return 0;
 118         if (expr->symbol->ctype.modifiers & MOD_INLINE)
 119                 return 1;
 120         return 0;
 121 }
 122
 123 static int is_noreturn_func(struct expression *expr)
 124 {
 125         if (expr->type != EXPR_SYMBOL || !expr->symbol)
 126                 return 0;
 127         if (expr->symbol->ctype.modifiers & MOD_NORETURN)
 128                 return 1;
 129         return 0;
 130 }
 131
 132 int inlinable(struct expression *expr)
 133 {
 134         struct symbol *sym;
 135
 136         if (__inline_fn)  /* don't nest */
 137                 return 0;
 138
 139         if (expr->type != EXPR_SYMBOL || !expr->symbol)
 140                 return 0;
 141         if (is_no_inline_function(expr->symbol->ident->name))
 142                 return 0;
 143         sym = get_base_type(expr->symbol);
 144         if (sym->stmt && sym->stmt->type == STMT_COMPOUND) {
 145                 if (ptr_list_size((struct ptr_list *)sym->stmt->stmts) <= 10)
 146                         return 1;
 147                 return 0;
 148         }
 149         if (sym->inline_stmt && sym->inline_stmt->type == STMT_COMPOUND) {
 150                 if (ptr_list_size((struct ptr_list *)sym->inline_stmt->stmts) <= 10)
 151                         return 1;
 152                 return 0;
 153         }
 154         return 0;
 155 }
 156
 157 void __process_post_op_stack(void)
 158 {
 159         struct expression *expr;
 160
 161         FOR_EACH_PTR(post_op_stack, expr) {
 162                 __pass_to_client(expr, OP_HOOK);
 163         } END_FOR_EACH_PTR(expr);
 164
 165         __free_ptr_list((struct ptr_list **)&post_op_stack);
 166 }
 167
 168 void __split_expr(struct expression *expr)
 169 {
 170         if (!expr)
 171                 return;
 172
 173         // sm_msg(" Debug expr_type %d %s", expr->type, show_special(expr->op));
 174
 175         if (__in_fake_assign && expr->type != EXPR_ASSIGNMENT)
 176                 return;
 177         if (__in_fake_assign >= 4)  /* don't allow too much nesting */
 178                 return;
 179
 180         push_expression(&big_expression_stack, expr);
 181         set_position(expr->pos);
 182         __pass_to_client(expr, EXPR_HOOK);
 183
 184         switch (expr->type) {
 185         case EXPR_PREOP:
 186                 if (expr->op == '*')
 187                         __pass_to_client(expr, DEREF_HOOK);
 188                 __split_expr(expr->unop);
 189                 __pass_to_client(expr, OP_HOOK);
 190                 break;
 191         case EXPR_POSTOP:
 192                 __split_expr(expr->unop);
 193                 push_expression(&post_op_stack, expr);
 194                 break;
 195         case EXPR_STATEMENT:
 196                 __expr_stmt_count++;
 197                 __split_stmt(expr->statement);
 198                 __expr_stmt_count--;
 199                 break;
 200         case EXPR_LOGICAL:
 201         case EXPR_COMPARE:
 202                 __pass_to_client(expr, LOGIC_HOOK);
 203                 __handle_logic(expr);
 204                 break;
 205         case EXPR_BINOP:
 206                 __pass_to_client(expr, BINOP_HOOK);
 207         case EXPR_COMMA:
 208                 __split_expr(expr->left);
 209                 __process_post_op_stack();
 210                 __split_expr(expr->right);
 211                 break;
 212         case EXPR_ASSIGNMENT: {
 213                 struct expression *tmp;
 214
 215                 if (!expr->right)
 216                         break;
 217
 218                 __pass_to_client(expr, RAW_ASSIGNMENT_HOOK);
 219
 220                 /* foo = !bar() */
 221                 if (__handle_condition_assigns(expr))
 222                         break;
 223                 /* foo = (x < 5 ? foo : 5); */
 224                 if (__handle_select_assigns(expr))
 225                         break;
 226                 /* foo = ({frob(); frob(); frob(); 1;}) */
 227                 if (__handle_expr_statement_assigns(expr))
 228                         break;
 229
 230                 __split_expr(expr->right);
 231                 if (outside_of_function())
 232                         __pass_to_client(expr, GLOBAL_ASSIGNMENT_HOOK);
 233                 else
 234                         __pass_to_client(expr, ASSIGNMENT_HOOK);
 235
 236                 __fake_struct_member_assignments(expr);
 237
 238                 tmp = strip_expr(expr->right);
 239                 if (tmp->type == EXPR_CALL)
 240                         __pass_to_client(expr, CALL_ASSIGNMENT_HOOK);
 241                 if (get_macro_name(tmp->pos) &&
 242                     get_macro_name(expr->pos) != get_macro_name(tmp->pos))
 243                         __pass_to_client(expr, MACRO_ASSIGNMENT_HOOK);
 244                 __split_expr(expr->left);
 245                 break;
 246         }
 247         case EXPR_DEREF:
 248                 __pass_to_client(expr, DEREF_HOOK);
 249                 __split_expr(expr->deref);
 250                 break;
 251         case EXPR_SLICE:
 252                 __split_expr(expr->base);
 253                 break;
 254         case EXPR_CAST:
 255         case EXPR_FORCE_CAST:
 256                 __pass_to_client(expr, CAST_HOOK);
 257                 __split_expr(expr->cast_expression);
 258                 break;
 259         case EXPR_SIZEOF:
 260                 if (expr->cast_expression)
 261                         __pass_to_client(strip_parens(expr->cast_expression),
 262                                          SIZEOF_HOOK);
 263                 break;
 264         case EXPR_OFFSETOF:
 265         case EXPR_ALIGNOF:
 266                 evaluate_expression(expr);
 267                 break;
 268         case EXPR_CONDITIONAL:
 269         case EXPR_SELECT:
 270                 if (known_condition_true(expr->conditional)) {
 271                         __split_expr(expr->cond_true);
 272                         break;
 273                 }
 274                 if (known_condition_false(expr->conditional)) {
 275                         __split_expr(expr->cond_false);
 276                         break;
 277                 }
 278                 __pass_to_client(expr, SELECT_HOOK);
 279                 __split_whole_condition(expr->conditional);
 280                 __split_expr(expr->cond_true);
 281                 __push_true_states();
 282                 __use_false_states();
 283                 __split_expr(expr->cond_false);
 284                 __merge_true_states();
 285                 break;
 286         case EXPR_CALL:
 287                 if (sym_name_is("__builtin_constant_p", expr->fn))
 288                         break;
 289                 split_expr_list(expr->args);
 290                 __split_expr(expr->fn);
 291                 if (is_inline_func(expr->fn))
 292                         add_inline_function(expr->fn->symbol);
 293                 if (inlinable(expr->fn))
 294                         __inline_call = 1;
 295                 __process_post_op_stack();
 296                 __pass_to_client(expr, FUNCTION_CALL_HOOK);
 297                 __inline_call = 0;
 298                 if (inlinable(expr->fn)) {
 299                         parse_inline(expr);
 300                 }
 301                 __pass_to_client(expr, CALL_HOOK_AFTER_INLINE);
 302                 if (is_noreturn_func(expr->fn))
 303                         nullify_path();
 304                 break;
 305         case EXPR_INITIALIZER:
 306                 split_expr_list(expr->expr_list);
 307                 break;
 308         case EXPR_IDENTIFIER:
 309                 __split_expr(expr->ident_expression);
 310                 break;
 311         case EXPR_INDEX:
 312                 __split_expr(expr->idx_expression);
 313                 break;
 314         case EXPR_POS:
 315                 __split_expr(expr->init_expr);
 316                 break;
 317         case EXPR_SYMBOL:
 318                 __pass_to_client(expr, SYM_HOOK);
 319                 break;
 320         case EXPR_STRING:
 321                 __pass_to_client(expr, STRING_HOOK);
 322                 break;
 323         default:
 324                 break;
 325         };
 326         pop_expression(&big_expression_stack);
 327 }
 328
 329 static int is_forever_loop(struct statement *stmt)
 330 {
 331         struct expression *expr;
 332
 333         expr = strip_expr(stmt->iterator_pre_condition);
 334         if (!expr)
 335                 expr = stmt->iterator_post_condition;
 336         if (!expr) {
 337                 /* this is a for(;;) loop... */
 338                 return 1;
 339         }
 340
 341         if (expr->type == EXPR_VALUE && expr->value == 1)
 342                 return 1;
 343
 344         return 0;
 345 }
 346
 347 static int loop_num;
 348 static char *get_loop_name(int num)
 349 {
 350         char buf[256];
 351
 352         snprintf(buf, 255, "-loop%d", num);
 353         buf[255] = '\0';
 354         return alloc_sname(buf);
 355 }
 356
 357 /*
 358  * Pre Loops are while and for loops.
 359  */
 360 static void handle_pre_loop(struct statement *stmt)
 361 {
 362         int once_through; /* we go through the loop at least once */
 363         struct sm_state *extra_sm = NULL;
 364         int unchanged = 0;
 365         char *loop_name;
 366         struct state_list *slist = NULL;
 367         struct sm_state *sm = NULL;
 368
 369         loop_name = get_loop_name(loop_num);
 370         loop_num++;
 371
 372         __split_stmt(stmt->iterator_pre_statement);
 373
 374         once_through = implied_condition_true(stmt->iterator_pre_condition);
 375
 376         loop_count++;
 377         __push_continues();
 378         __push_breaks();
 379
 380         __merge_gotos(loop_name);
 381
 382         extra_sm = __extra_handle_canonical_loops(stmt, &slist);
 383         __in_pre_condition++;
 384         __pass_to_client(stmt, PRELOOP_HOOK);
 385         __split_whole_condition(stmt->iterator_pre_condition);
 386         __in_pre_condition--;
 387         FOR_EACH_PTR(slist, sm) {
 388                 set_state(sm->owner, sm->name, sm->sym, sm->state);
 389         } END_FOR_EACH_PTR(sm);
 390         free_slist(&slist);
 391         if (extra_sm)
 392                 extra_sm = get_sm_state(extra_sm->owner, extra_sm->name, extra_sm->sym);
 393
 394         if (option_assume_loops)
 395                 once_through = 1;
 396
 397         __split_stmt(stmt->iterator_statement);
 398         __warn_on_silly_pre_loops();
 399         if (is_forever_loop(stmt)) {
 400                 struct state_list *slist;
 401
 402                 __save_gotos(loop_name);
 403
 404                 __push_fake_cur_slist();
 405                 __split_stmt(stmt->iterator_post_statement);
 406                 slist = stree_to_slist(__pop_fake_cur_slist());
 407
 408                 __discard_continues();
 409                 __discard_false_states();
 410                 __use_breaks();
 411
 412                 if (!__path_is_null())
 413                         __merge_slist_into_cur(slist);
 414                 free_slist(&slist);
 415         } else {
 416                 __merge_continues();
 417                 unchanged = __iterator_unchanged(extra_sm);
 418                 __split_stmt(stmt->iterator_post_statement);
 419                 __save_gotos(loop_name);
 420                 __split_whole_condition(stmt->iterator_pre_condition);
 421                 nullify_path();
 422                 __merge_false_states();
 423                 if (once_through)
 424                         __discard_false_states();
 425                 else
 426                         __merge_false_states();
 427
 428                 if (extra_sm && unchanged)
 429                         __extra_pre_loop_hook_after(extra_sm,
 430                                                 stmt->iterator_post_statement,
 431                                                 stmt->iterator_pre_condition);
 432                 __merge_breaks();
 433         }
 434         loop_count--;
 435 }
 436
 437 /*
 438  * Post loops are do {} while();
 439  */
 440 static void handle_post_loop(struct statement *stmt)
 441 {
 442         char *loop_name;
 443
 444         loop_name = get_loop_name(loop_num);
 445         loop_num++;
 446         loop_count++;
 447
 448         __push_continues();
 449         __push_breaks();
 450         __merge_gotos(loop_name);
 451         __split_stmt(stmt->iterator_statement);
 452         __merge_continues();
 453         if (!is_zero(stmt->iterator_post_condition))
 454                 __save_gotos(loop_name);
 455
 456         if (is_forever_loop(stmt)) {
 457                 __use_breaks();
 458         } else {
 459                 __split_whole_condition(stmt->iterator_post_condition);
 460                 __use_false_states();
 461                 __merge_breaks();
 462         }
 463         loop_count--;
 464 }
 465
 466 static int empty_statement(struct statement *stmt)
 467 {
 468         if (!stmt)
 469                 return 0;
 470         if (stmt->type == STMT_EXPRESSION && !stmt->expression)
 471                 return 1;
 472         return 0;
 473 }
 474
 475 static int last_stmt_on_same_line()
 476 {
 477         struct statement *stmt;
 478         int i = 0;
 479
 480         FOR_EACH_PTR_REVERSE(big_statement_stack, stmt) {
 481                 if (!i++)
 482                         continue;
 483                 if  (stmt->pos.line == get_lineno())
 484                         return 1;
 485                 return 0;
 486         } END_FOR_EACH_PTR_REVERSE(stmt);
 487         return 0;
 488 }
 489
 490 static struct statement *last_stmt;
 491 static int is_last_stmt(struct statement *stmt)
 492 {
 493         if (stmt == last_stmt)
 494                 return 1;
 495         return 0;
 496 }
 497
 498 static void print_unreached_initializers(struct symbol_list *sym_list)
 499 {
 500         struct symbol *sym;
 501
 502         FOR_EACH_PTR(sym_list, sym) {
 503                 if (sym->initializer)
 504                         sm_msg("info: '%s' is not actually initialized (unreached code).",
 505                                 (sym->ident ? sym->ident->name : "this variable"));
 506         } END_FOR_EACH_PTR(sym);
 507 }
 508
 509 static void print_unreached(struct statement *stmt)
 510 {
 511         static int print = 1;
 512
 513         if (__inline_fn)
 514                 return;
 515
 516         if (!__path_is_null()) {
 517                 print = 1;
 518                 return;
 519         }
 520         if (!print)
 521                 return;
 522
 523         switch (stmt->type) {
 524         case STMT_COMPOUND: /* after a switch before a case stmt */
 525         case STMT_RANGE:
 526         case STMT_CASE:
 527         case STMT_LABEL:
 528                 return;
 529         case STMT_DECLARATION: /* switch (x) { int a; case foo: ... */
 530                 print_unreached_initializers(stmt->declaration);
 531                 return;
 532         case STMT_RETURN: /* gcc complains if you don't have a return statement */
 533                 if (is_last_stmt(stmt))
 534                         return;
 535                 break;
 536         case STMT_GOTO:
 537                 /* people put extra breaks inside switch statements */
 538                 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE &&
 539                     strcmp(stmt->goto_label->ident->name, "break") == 0)
 540                         return;
 541                 break;
 542         default:
 543                 break;
 544         }
 545         if (empty_statement(stmt))
 546                 return;
 547         if (!option_spammy)
 548                 return;
 549         sm_msg("info: ignoring unreachable code.");
 550         print = 0;
 551 }
 552
 553 static void split_asm_constraints(struct expression_list *expr_list)
 554 {
 555         struct expression *expr;
 556         int state = 0;
 557
 558         FOR_EACH_PTR(expr_list, expr) {
 559                 switch (state) {
 560                 case 0: /* identifier */
 561                 case 1: /* constraint */
 562                         state++;
 563                         continue;
 564                 case 2: /* expression */
 565                         state = 0;
 566                         __split_expr(expr);
 567                         continue;
 568                 }
 569         } END_FOR_EACH_PTR(expr);
 570 }
 571
 572 static int is_case_val(struct statement *stmt, sval_t sval)
 573 {
 574         sval_t case_sval;
 575
 576         if (stmt->type != STMT_CASE)
 577                 return 0;
 578         if (!stmt->case_expression) {
 579                 __set_default();
 580                 return 1;
 581         }
 582         if (!get_value(stmt->case_expression, &case_sval))
 583                 return 0;
 584         if (case_sval.value == sval.value)
 585                 return 1;
 586         return 0;
 587 }
 588
 589 static void split_known_switch(struct statement *stmt, sval_t sval)
 590 {
 591         struct statement *tmp;
 592
 593         __split_expr(stmt->switch_expression);
 594
 595         push_expression(&switch_expr_stack, stmt->switch_expression);
 596         __save_switch_states(top_expression(switch_expr_stack));
 597         nullify_path();
 598         __push_default();
 599         __push_breaks();
 600
 601         stmt = stmt->switch_statement;
 602
 603         if (!last_stmt)
 604                 last_stmt = last_ptr_list((struct ptr_list *)stmt->stmts);
 605
 606         __push_scope_hooks();
 607         FOR_EACH_PTR(stmt->stmts, tmp) {
 608                 __smatch_lineno = tmp->pos.line;
 609                 if (is_case_val(tmp, sval)) {
 610                         __merge_switches(top_expression(switch_expr_stack),
 611                                          stmt->case_expression);
 612                         __pass_case_to_client(top_expression(switch_expr_stack),
 613                                               stmt->case_expression);
 614                 }
 615                 if (__path_is_null())
 616                         continue;
 617                 __split_stmt(tmp);
 618                 if (__path_is_null()) {
 619                         __set_default();
 620                         goto out;
 621                 }
 622         } END_FOR_EACH_PTR(tmp);
 623 out:
 624         __call_scope_hooks();
 625         if (!__pop_default())
 626                 __merge_switches(top_expression(switch_expr_stack),
 627                                  NULL);
 628         __discard_switches();
 629         __merge_breaks();
 630         pop_expression(&switch_expr_stack);
 631 }
 632
 633 void __split_stmt(struct statement *stmt)
 634 {
 635         sval_t sval;
 636
 637         if (!stmt)
 638                 goto out;
 639
 640         if (out_of_memory() || __bail_on_rest_of_function) {
 641                 static char *printed = NULL;
 642
 643                 if (printed != cur_func)
 644                         sm_msg("Function too hairy.  Giving up.");
 645                 final_pass = 0;  /* turn off sm_msg() from here */
 646                 printed = cur_func;
 647                 return;
 648         }
 649
 650         add_ptr_list(&big_statement_stack, stmt);
 651         free_expression_stack(&big_expression_stack);
 652         set_position(stmt->pos);
 653         print_unreached(stmt);
 654         __pass_to_client(stmt, STMT_HOOK);
 655
 656         switch (stmt->type) {
 657         case STMT_DECLARATION:
 658                 split_declaration(stmt->declaration);
 659                 break;
 660         case STMT_RETURN:
 661                 __split_expr(stmt->ret_value);
 662                 __pass_to_client(stmt->ret_value, RETURN_HOOK);
 663                 nullify_path();
 664                 break;
 665         case STMT_EXPRESSION:
 666                 __split_expr(stmt->expression);
 667                 break;
 668         case STMT_COMPOUND: {
 669                 struct statement *tmp;
 670
 671                 if (!last_stmt)
 672                         last_stmt = last_ptr_list((struct ptr_list *)stmt->stmts);
 673                 __push_scope_hooks();
 674                 FOR_EACH_PTR(stmt->stmts, tmp) {
 675                         __split_stmt(tmp);
 676                 } END_FOR_EACH_PTR(tmp);
 677                 __call_scope_hooks();
 678                 break;
 679         }
 680         case STMT_IF:
 681                 if (known_condition_true(stmt->if_conditional)) {
 682                         __split_stmt(stmt->if_true);
 683                         break;
 684                 }
 685                 if (known_condition_false(stmt->if_conditional)) {
 686                         __split_stmt(stmt->if_false);
 687                         break;
 688                 }
 689                 if (option_known_conditions &&
 690                     implied_condition_true(stmt->if_conditional)) {
 691                         sm_info("this condition is true.");
 692                         __split_stmt(stmt->if_true);
 693                         break;
 694                 }
 695                 if (option_known_conditions &&
 696                     implied_condition_false(stmt->if_conditional)) {
 697                         sm_info("this condition is false.");
 698                         __split_stmt(stmt->if_false);
 699                         break;
 700                 }
 701                 __split_whole_condition(stmt->if_conditional);
 702                 __split_stmt(stmt->if_true);
 703                 if (empty_statement(stmt->if_true) &&
 704                         last_stmt_on_same_line() &&
 705                         !get_macro_name(stmt->if_true->pos))
 706                         sm_msg("warn: if();");
 707                 __push_true_states();
 708                 __use_false_states();
 709                 __split_stmt(stmt->if_false);
 710                 __merge_true_states();
 711                 break;
 712         case STMT_ITERATOR:
 713                 if (stmt->iterator_pre_condition)
 714                         handle_pre_loop(stmt);
 715                 else if (stmt->iterator_post_condition)
 716                         handle_post_loop(stmt);
 717                 else {
 718                         // these are for(;;) type loops.
 719                         handle_pre_loop(stmt);
 720                 }
 721                 break;
 722         case STMT_SWITCH:
 723                 if (get_value(stmt->switch_expression, &sval)) {
 724                         split_known_switch(stmt, sval);
 725                         break;
 726                 }
 727                 __split_expr(stmt->switch_expression);
 728                 push_expression(&switch_expr_stack, stmt->switch_expression);
 729                 __save_switch_states(top_expression(switch_expr_stack));
 730                 nullify_path();
 731                 __push_default();
 732                 __push_breaks();
 733                 __split_stmt(stmt->switch_statement);
 734                 if (!__pop_default())
 735                         __merge_switches(top_expression(switch_expr_stack),
 736                                       NULL);
 737                 __discard_switches();
 738                 __merge_breaks();
 739                 pop_expression(&switch_expr_stack);
 740                 break;
 741         case STMT_CASE:
 742                 __merge_switches(top_expression(switch_expr_stack),
 743                                       stmt->case_expression);
 744                 __pass_case_to_client(top_expression(switch_expr_stack),
 745                                       stmt->case_expression);
 746                 if (!stmt->case_expression)
 747                         __set_default();
 748                 __split_expr(stmt->case_expression);
 749                 __split_expr(stmt->case_to);
 750                 __split_stmt(stmt->case_statement);
 751                 break;
 752         case STMT_LABEL:
 753                 if (stmt->label_identifier &&
 754                     stmt->label_identifier->type == SYM_LABEL &&
 755                     stmt->label_identifier->ident) {
 756                         loop_count |= 0x80000000;
 757                         __merge_gotos(stmt->label_identifier->ident->name);
 758                 }
 759                 __split_stmt(stmt->label_statement);
 760                 break;
 761         case STMT_GOTO:
 762                 __split_expr(stmt->goto_expression);
 763                 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE) {
 764                         if (!strcmp(stmt->goto_label->ident->name, "break")) {
 765                                 __process_breaks();
 766                         } else if (!strcmp(stmt->goto_label->ident->name,
 767                                            "continue")) {
 768                                 __process_continues();
 769                         }
 770                 } else if (stmt->goto_label &&
 771                            stmt->goto_label->type == SYM_LABEL &&
 772                            stmt->goto_label->ident) {
 773                         __save_gotos(stmt->goto_label->ident->name);
 774                 }
 775                 nullify_path();
 776                 break;
 777         case STMT_NONE:
 778                 break;
 779         case STMT_ASM:
 780                 __pass_to_client(stmt, ASM_HOOK);
 781                 __split_expr(stmt->asm_string);
 782                 split_asm_constraints(stmt->asm_outputs);
 783                 split_asm_constraints(stmt->asm_inputs);
 784                 split_asm_constraints(stmt->asm_clobbers);
 785                 break;
 786         case STMT_CONTEXT:
 787                 break;
 788         case STMT_RANGE:
 789                 __split_expr(stmt->range_expression);
 790                 __split_expr(stmt->range_low);
 791                 __split_expr(stmt->range_high);
 792                 break;
 793         }
 794         __pass_to_client(stmt, STMT_HOOK_AFTER);
 795 out:
 796         __process_post_op_stack();
 797 }
 798
 799 static void split_expr_list(struct expression_list *expr_list)
 800 {
 801         struct expression *expr;
 802
 803         FOR_EACH_PTR(expr_list, expr) {
 804                 __split_expr(expr);
 805                 __process_post_op_stack();
 806         } END_FOR_EACH_PTR(expr);
 807 }
 808
 809 static void split_sym(struct symbol *sym)
 810 {
 811         if (!sym)
 812                 return;
 813         if (!(sym->namespace & NS_SYMBOL))
 814                 return;
 815
 816         __split_stmt(sym->stmt);
 817         __split_expr(sym->array_size);
 818         split_symlist(sym->arguments);
 819         split_symlist(sym->symbol_list);
 820         __split_stmt(sym->inline_stmt);
 821         split_symlist(sym->inline_symbol_list);
 822 }
 823
 824 static void split_symlist(struct symbol_list *sym_list)
 825 {
 826         struct symbol *sym;
 827
 828         FOR_EACH_PTR(sym_list, sym) {
 829                 split_sym(sym);
 830         } END_FOR_EACH_PTR(sym);
 831 }
 832
 833 typedef void (fake_cb)(struct expression *expr);
 834
 835 static int member_to_number(struct expression *expr, struct ident *member)
 836 {
 837         struct symbol *type, *tmp;
 838         char *name;
 839         int i;
 840
 841         if (!member)
 842                 return -1;
 843         name = member->name;
 844
 845         type = get_type(expr);
 846         if (!type || type->type != SYM_STRUCT)
 847                 return -1;
 848
 849         i = -1;
 850         FOR_EACH_PTR(type->symbol_list, tmp) {
 851                 i++;
 852                 if (!tmp->ident)
 853                         continue;
 854                 if (strcmp(name, tmp->ident->name) == 0)
 855                         return i;
 856         } END_FOR_EACH_PTR(tmp);
 857         return -1;
 858 }
 859
 860 static struct ident *number_to_member(struct expression *expr, int num)
 861 {
 862         struct symbol *type, *member;
 863         int i = 0;
 864
 865         type = get_type(expr);
 866         if (!type || type->type != SYM_STRUCT)
 867                 return NULL;
 868
 869         FOR_EACH_PTR(type->symbol_list, member) {
 870                 if (i == num)
 871                         return member->ident;
 872                 i++;
 873         } END_FOR_EACH_PTR(member);
 874         return NULL;
 875 }
 876
 877 static void fake_element_assigns_helper(struct expression *array, struct expression_list *expr_list, fake_cb *fake_cb);
 878
 879 struct member_set {
 880         struct ident *ident;
 881         int set;
 882 };
 883
 884 static struct member_set *alloc_member_set(struct symbol *type)
 885 {
 886         struct member_set *member_set;
 887         struct symbol *member;
 888         int member_count;
 889         int member_idx;
 890
 891         member_count = ptr_list_size((struct ptr_list *)type->symbol_list);
 892         member_set = malloc(member_count * sizeof(*member_set));
 893         member_idx = 0;
 894         FOR_EACH_PTR(type->symbol_list, member) {
 895                 member_set[member_idx].ident = member->ident;
 896                 member_set[member_idx].set = 0;
 897                 member_idx++;
 898         } END_FOR_EACH_PTR(member);
 899
 900         return member_set;
 901 }
 902
 903 static void mark_member_as_set(struct symbol *type, struct member_set *member_set, struct ident *ident)
 904 {
 905         int member_count = ptr_list_size((struct ptr_list *)type->symbol_list);
 906         int i;
 907
 908         for (i = 0; i < member_count; i++) {
 909                 if (member_set[i].ident == ident) {
 910                         member_set[i].set = 1;
 911                         return;
 912                 }
 913         }
 914 //      crap.  this is buggy.
 915 //      sm_msg("internal smatch error in initializer %s.%s", type->ident->name, ident->name);
 916 }
 917
 918 static void set_unset_to_zero(struct expression *symbol, struct symbol *type, struct member_set *member_set)
 919 {
 920         struct expression *deref, *assign;
 921         struct symbol *member, *member_type;
 922         int member_idx;
 923
 924         member_idx = 0;
 925         FOR_EACH_PTR(type->symbol_list, member) {
 926                 if (!member->ident || member_set[member_idx].set) {
 927                         member_idx++;
 928                         continue;
 929                 }
 930                 member_type = get_real_base_type(member);
 931                 if (!member_type || member_type->type == SYM_ARRAY) {
 932                         member_idx++;
 933                         continue;
 934                 }
 935                 /* TODO: this should be handled recursively and not ignored */
 936                 if (member_type->type == SYM_STRUCT || member_type->type == SYM_UNION) {
 937                         member_idx++;
 938                         continue;
 939                 }
 940                 deref = member_expression(symbol, '.', member->ident);
 941                 assign = assign_expression(deref, zero_expr());
 942                 __split_expr(assign);
 943                 member_idx++;
 944         } END_FOR_EACH_PTR(member);
 945
 946 }
 947
 948 static void fake_member_assigns_helper(struct expression *symbol, struct expression_list *members, fake_cb *fake_cb)
 949 {
 950         struct expression *deref, *assign, *tmp;
 951         struct symbol *struct_type, *type;
 952         struct ident *member;
 953         int member_idx;
 954         struct member_set *member_set;
 955
 956         struct_type = get_type(symbol);
 957         if (!struct_type ||
 958             (struct_type->type != SYM_STRUCT && struct_type->type != SYM_UNION))
 959                 return;
 960
 961         member_set = alloc_member_set(struct_type);
 962
 963         member_idx = 0;
 964         FOR_EACH_PTR(members, tmp) {
 965                 member = number_to_member(symbol, member_idx);
 966                 while (tmp->type == EXPR_IDENTIFIER) {
 967                         member = tmp->expr_ident;
 968                         member_idx = member_to_number(symbol, member);
 969                         tmp = tmp->ident_expression;
 970                 }
 971                 mark_member_as_set(struct_type, member_set, member);
 972                 member_idx++;
 973                 deref = member_expression(symbol, '.', member);
 974                 if (tmp->type == EXPR_INITIALIZER) {
 975                         type = get_type(deref);
 976                         if (type && type->type == SYM_ARRAY)
 977                                 fake_element_assigns_helper(deref, tmp->expr_list, fake_cb);
 978                         else
 979                                 fake_member_assigns_helper(deref, tmp->expr_list, fake_cb);
 980                 } else {
 981                         assign = assign_expression(deref, tmp);
 982                         fake_cb(assign);
 983                 }
 984         } END_FOR_EACH_PTR(tmp);
 985
 986         set_unset_to_zero(symbol, struct_type, member_set);
 987 }
 988
 989 static void fake_member_assigns(struct symbol *sym, fake_cb *fake_cb)
 990 {
 991         fake_member_assigns_helper(symbol_expression(sym),
 992                                    sym->initializer->expr_list, fake_cb);
 993 }
 994
 995 static void fake_element_assigns_helper(struct expression *array, struct expression_list *expr_list, fake_cb *fake_cb)
 996 {
 997         struct expression *offset, *binop, *assign, *tmp;
 998         struct symbol *type;
 999         int idx;
1000
1001         idx = 0;
1002         FOR_EACH_PTR(expr_list, tmp) {
1003                 if (tmp->type == EXPR_INDEX) {
1004                         if (tmp->idx_from != tmp->idx_to)
1005                                 return;
1006                         idx = tmp->idx_from;
1007                         if (!tmp->idx_expression)
1008                                 goto next;
1009                         tmp = tmp->idx_expression;
1010                 }
1011                 offset = value_expr(idx);
1012                 binop = array_element_expression(array, offset);
1013                 if (tmp->type == EXPR_INITIALIZER) {
1014                         type = get_type(binop);
1015                         if (type && type->type == SYM_ARRAY)
1016                                 fake_element_assigns_helper(binop, tmp->expr_list, fake_cb);
1017                         else
1018                                 fake_member_assigns_helper(binop, tmp->expr_list, fake_cb);
1019                 } else {
1020                         assign = assign_expression(binop, tmp);
1021                         fake_cb(assign);
1022                 }
1023 next:
1024                 idx++;
1025         } END_FOR_EACH_PTR(tmp);
1026 }
1027
1028 static void fake_element_assigns(struct symbol *sym, fake_cb *fake_cb)
1029 {
1030         fake_element_assigns_helper(symbol_expression(sym), sym->initializer->expr_list, fake_cb);
1031 }
1032
1033 static void fake_assign_expr(struct symbol *sym)
1034 {
1035         struct expression *assign, *symbol;
1036
1037         symbol = symbol_expression(sym);
1038         assign = assign_expression(symbol, sym->initializer);
1039         __split_expr(assign);
1040 }
1041
1042 static void call_split_expr(struct expression *expr)
1043 {
1044         __split_expr(expr);
1045 }
1046
1047 static void do_initializer_stuff(struct symbol *sym)
1048 {
1049         if (!sym->initializer)
1050                 return;
1051
1052         if (sym->initializer->type == EXPR_INITIALIZER) {
1053                 if (get_real_base_type(sym)->type == SYM_ARRAY)
1054                         fake_element_assigns(sym, call_split_expr);
1055                 else
1056                         fake_member_assigns(sym, call_split_expr);
1057         } else {
1058                 fake_assign_expr(sym);
1059         }
1060 }
1061
1062 static void split_declaration(struct symbol_list *sym_list)
1063 {
1064         struct symbol *sym;
1065
1066         FOR_EACH_PTR(sym_list, sym) {
1067                 __pass_to_client(sym, DECLARATION_HOOK);
1068                 do_initializer_stuff(sym);
1069                 split_sym(sym);
1070         } END_FOR_EACH_PTR(sym);
1071 }
1072
1073 static void call_global_assign_hooks(struct expression *assign)
1074 {
1075         __pass_to_client(assign, GLOBAL_ASSIGNMENT_HOOK);
1076 }
1077
1078 static void fake_global_assign(struct symbol *sym)
1079 {
1080         struct expression *assign, *symbol;
1081
1082         if (get_real_base_type(sym)->type == SYM_ARRAY) {
1083                 if (sym->initializer && sym->initializer->type == EXPR_INITIALIZER) {
1084                         fake_element_assigns(sym, call_global_assign_hooks);
1085                 } else if (sym->initializer) {
1086                         symbol = symbol_expression(sym);
1087                         assign = assign_expression(symbol, sym->initializer);
1088                         __pass_to_client(assign, GLOBAL_ASSIGNMENT_HOOK);
1089                 } else {
1090                         fake_element_assigns_helper(symbol_expression(sym), NULL, call_global_assign_hooks);
1091                 }
1092         } else if (get_real_base_type(sym)->type == SYM_STRUCT) {
1093                 if (sym->initializer && sym->initializer->type == EXPR_INITIALIZER) {
1094                         fake_member_assigns(sym, call_global_assign_hooks);
1095                 } else if (sym->initializer) {
1096                         symbol = symbol_expression(sym);
1097                         assign = assign_expression(symbol, sym->initializer);
1098                         __pass_to_client(assign, GLOBAL_ASSIGNMENT_HOOK);
1099                 } else {
1100                         fake_member_assigns_helper(symbol_expression(sym), NULL, call_global_assign_hooks);
1101                 }
1102         } else {
1103                 symbol = symbol_expression(sym);
1104                 if (sym->initializer)
1105                         assign = assign_expression(symbol, sym->initializer);
1106                 else
1107                         assign = assign_expression(symbol, zero_expr());
1108                 __pass_to_client(assign, GLOBAL_ASSIGNMENT_HOOK);
1109         }
1110 }
1111
1112 static void start_function_definition(struct symbol *sym)
1113 {
1114         __in_function_def = 1;
1115         __pass_to_client(sym, FUNC_DEF_HOOK);
1116         __in_function_def = 0;
1117         __pass_to_client(sym, AFTER_DEF_HOOK);
1118
1119 }
1120
1121 static void split_function(struct symbol *sym)
1122 {
1123         struct symbol *base_type = get_base_type(sym);
1124
1125         cur_func_sym = sym;
1126         if (sym->ident)
1127                 cur_func = sym->ident->name;
1128         __smatch_lineno = sym->pos.line;
1129         last_stmt = NULL;
1130         loop_count = 0;
1131         sm_debug("new function:  %s\n", cur_func);
1132         __slist_id = 0;
1133         if (option_two_passes) {
1134                 __unnullify_path();
1135                 loop_num = 0;
1136                 final_pass = 0;
1137                 start_function_definition(sym);
1138                 __split_stmt(base_type->stmt);
1139                 __split_stmt(base_type->inline_stmt);
1140                 nullify_path();
1141         }
1142         __unnullify_path();
1143         loop_num = 0;
1144         start_function_definition(sym);
1145         __split_stmt(base_type->stmt);
1146         __split_stmt(base_type->inline_stmt);
1147         __pass_to_client(sym, END_FUNC_HOOK);
1148         __pass_to_client(sym, AFTER_FUNC_HOOK);
1149         cur_func_sym = NULL;
1150         cur_func = NULL;
1151         clear_all_states();
1152         free_data_info_allocs();
1153         free_expression_stack(&switch_expr_stack);
1154         __free_ptr_list((struct ptr_list **)&big_statement_stack);
1155         __bail_on_rest_of_function = 0;
1156 }
1157
1158 static void parse_inline(struct expression *call)
1159 {
1160         struct symbol *base_type;
1161         int loop_num_bak = loop_num;
1162         int final_pass_bak = final_pass;
1163         char *cur_func_bak = cur_func;
1164         struct statement_list *big_statement_stack_bak = big_statement_stack;
1165         struct expression_list *big_expression_stack_bak = big_expression_stack;
1166         struct expression_list *switch_expr_stack_bak = switch_expr_stack;
1167         struct symbol *cur_func_sym_bak = cur_func_sym;
1168
1169         __pass_to_client(call, INLINE_FN_START);
1170         final_pass = 0;  /* don't print anything */
1171         __inline_fn = call;
1172
1173         base_type = get_base_type(call->fn->symbol);
1174         cur_func_sym = call->fn->symbol;
1175         if (call->fn->symbol->ident)
1176                 cur_func = call->fn->symbol->ident->name;
1177         else
1178                 cur_func = NULL;
1179         set_position(call->fn->symbol->pos);
1180
1181         save_all_states();
1182         nullify_all_states();
1183         big_statement_stack = NULL;
1184         big_expression_stack = NULL;
1185         switch_expr_stack = NULL;
1186
1187         sm_debug("inline function:  %s\n", cur_func);
1188         __unnullify_path();
1189         loop_num = 0;
1190         start_function_definition(call->fn->symbol);
1191         __split_stmt(base_type->stmt);
1192         __split_stmt(base_type->inline_stmt);
1193         __pass_to_client(call->fn->symbol, END_FUNC_HOOK);
1194         __pass_to_client(call->fn->symbol, AFTER_FUNC_HOOK);
1195
1196         free_expression_stack(&switch_expr_stack);
1197         __free_ptr_list((struct ptr_list **)&big_statement_stack);
1198         nullify_path();
1199
1200         loop_num = loop_num_bak;
1201         final_pass = final_pass_bak;
1202         cur_func_sym = cur_func_sym_bak;
1203         cur_func = cur_func_bak;
1204         big_statement_stack = big_statement_stack_bak;
1205         big_expression_stack = big_expression_stack_bak;
1206         switch_expr_stack = switch_expr_stack_bak;
1207
1208         restore_all_states();
1209         set_position(call->pos);
1210         __inline_fn = NULL;
1211         __pass_to_client(call, INLINE_FN_END);
1212 }
1213
1214 static struct symbol_list *inlines_called;
1215 static void add_inline_function(struct symbol *sym)
1216 {
1217         static struct symbol_list *already_added;
1218         struct symbol *tmp;
1219
1220         FOR_EACH_PTR(already_added, tmp) {
1221                 if (tmp == sym)
1222                         return;
1223         } END_FOR_EACH_PTR(tmp);
1224
1225         add_ptr_list(&already_added, sym);
1226         add_ptr_list(&inlines_called, sym);
1227 }
1228
1229 static void process_inlines()
1230 {
1231         struct symbol *tmp;
1232
1233         FOR_EACH_PTR(inlines_called, tmp) {
1234                 split_function(tmp);
1235         } END_FOR_EACH_PTR(tmp);
1236         free_ptr_list(&inlines_called);
1237 }
1238
1239 static struct symbol *get_last_scoped_symbol(struct symbol_list *big_list, int use_static)
1240 {
1241         struct symbol *sym;
1242
1243         FOR_EACH_PTR_REVERSE(big_list, sym) {
1244                 if (!sym->scope)
1245                         continue;
1246                 if (use_static && sym->ctype.modifiers & MOD_STATIC)
1247                         return sym;
1248                 if (!use_static && !(sym->ctype.modifiers & MOD_STATIC))
1249                         return sym;
1250         } END_FOR_EACH_PTR_REVERSE(sym);
1251
1252         return NULL;
1253 }
1254
1255 static void split_inlines_in_scope(struct symbol *sym)
1256 {
1257         struct symbol *base;
1258         struct symbol_list *scope_list;
1259         int stream;
1260
1261         scope_list = sym->scope->symbols;
1262         stream = sym->pos.stream;
1263
1264         /* find the last static symbol in the file */
1265         FOR_EACH_PTR_REVERSE(scope_list, sym) {
1266                 if (sym->pos.stream != stream)
1267                         continue;
1268                 if (sym->type != SYM_NODE)
1269                         continue;
1270                 base = get_base_type(sym);
1271                 if (!base)
1272                         continue;
1273                 if (base->type != SYM_FN)
1274                         continue;
1275                 if (!base->inline_stmt)
1276                         continue;
1277                 add_inline_function(sym);
1278         } END_FOR_EACH_PTR_REVERSE(sym);
1279
1280         process_inlines();
1281 }
1282
1283 static void split_inlines(struct symbol_list *sym_list)
1284 {
1285         struct symbol *sym;
1286
1287         sym = get_last_scoped_symbol(sym_list, 0);
1288         if (sym)
1289                 split_inlines_in_scope(sym);
1290         sym = get_last_scoped_symbol(sym_list, 1);
1291         if (sym)
1292                 split_inlines_in_scope(sym);
1293 }
1294
1295 static void split_functions(struct symbol_list *sym_list)
1296 {
1297         struct symbol *sym;
1298
1299         FOR_EACH_PTR(sym_list, sym) {
1300                 set_position(sym->pos);
1301                 if (sym->type == SYM_NODE && get_base_type(sym)->type == SYM_FN) {
1302                         split_function(sym);
1303                         process_inlines();
1304                 } else {
1305                         __pass_to_client(sym, BASE_HOOK);
1306                         fake_global_assign(sym);
1307                 }
1308         } END_FOR_EACH_PTR(sym);
1309         split_inlines(sym_list);
1310         __pass_to_client(sym_list, END_FILE_HOOK);
1311 }
1312
1313 void smatch(int argc, char **argv)
1314 {
1315
1316         struct string_list *filelist = NULL;
1317         struct symbol_list *sym_list;
1318
1319         if (argc < 2) {
1320                 printf("Usage:  smatch [--debug] <filename.c>\n");
1321                 exit(1);
1322         }
1323         sparse_initialize(argc, argv, &filelist);
1324         FOR_EACH_PTR_NOTAG(filelist, base_file) {
1325                 if (option_file_output) {
1326                         char buf[256];
1327
1328                         snprintf(buf, sizeof(buf), "%s.smatch", base_file);
1329                         sm_outfd = fopen(buf, "w");
1330                         if (!sm_outfd) {
1331                                 printf("Error:  Cannot open %s\n", base_file);
1332                                 exit(1);
1333                         }
1334                 }
1335                 sym_list = sparse_keep_tokens(base_file);
1336                 split_functions(sym_list);
1337         } END_FOR_EACH_PTR_NOTAG(base_file);
1338 }