smatch_helper.c

   1 /*
   2  * sparse/smatch_helper.c
   3  *
   4  * Copyright (C) 2006 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * Miscellaneous helper functions.
  12  */
  13
  14 #include <stdlib.h>
  15 #include <stdio.h>
  16 #include "allocate.h"
  17 #include "smatch.h"
  18
  19 #define VAR_LEN 512
  20
  21 char *alloc_string(const char *str)
  22 {
  23         char *tmp;
  24
  25         if (!str)
  26                 return NULL;
  27         tmp = malloc(strlen(str) + 1);
  28         strcpy(tmp, str);
  29         return tmp;
  30 }
  31
  32 void free_string(char *str)
  33 {
  34         free(str);
  35 }
  36
  37 void remove_parens(char *str)
  38 {
  39         char *src, *dst;
  40
  41         dst = src = str;
  42         while (*src != '\0') {
  43                 if (*src == '(' || *src == ')') {
  44                         src++;
  45                         continue;
  46                 }
  47                 *dst++ = *src++;
  48         }
  49         *dst = *src;
  50 }
  51
  52 struct smatch_state *alloc_state_num(int num)
  53 {
  54         struct smatch_state *state;
  55         static char buff[256];
  56
  57         state = __alloc_smatch_state(0);
  58         snprintf(buff, 255, "%d", num);
  59         buff[255] = '\0';
  60         state->name = alloc_string(buff);
  61         state->data = INT_PTR(num);
  62         return state;
  63 }
  64
  65 void append(char *dest, const char *data, int buff_len)
  66 {
  67         strncat(dest, data, buff_len - strlen(dest) - 1);
  68 }
  69
  70 /*
  71  * If you have "foo(a, b, 1);" then use
  72  * get_argument_from_call_expr(expr, 0) to return the expression for
  73  * a.  Yes, it does start counting from 0.
  74  */
  75 struct expression *get_argument_from_call_expr(struct expression_list *args,
  76                                                int num)
  77 {
  78         struct expression *expr;
  79         int i = 0;
  80
  81         if (!args)
  82                 return NULL;
  83
  84         FOR_EACH_PTR(args, expr) {
  85                 if (i == num)
  86                         return expr;
  87                 i++;
  88         } END_FOR_EACH_PTR(expr);
  89         return NULL;
  90 }
  91
  92 static struct expression *get_array_expr(struct expression *expr)
  93 {
  94         struct symbol *type;
  95
  96         if (expr->type != EXPR_BINOP || expr->op != '+')
  97                 return NULL;
  98
  99         type = get_type(expr->left);
 100         if (!type || type->type != SYM_ARRAY)
 101                 return NULL;
 102         return expr->left;
 103 }
 104
 105 static void __get_variable_from_expr(struct symbol **sym_ptr, char *buf,
 106                                      struct expression *expr, int len,
 107                                      int *complicated, int no_parens)
 108 {
 109         struct expression *tmp;
 110
 111         switch (expr->type) {
 112         case EXPR_DEREF:
 113                 tmp = expr->deref;
 114                 if (tmp->op == '*')
 115                         tmp = tmp->unop;
 116
 117                 __get_variable_from_expr(sym_ptr, buf, tmp, len, complicated, no_parens);
 118
 119                 tmp = expr->deref;
 120                 if (tmp->op == '*')
 121                         append(buf, "->", len);
 122                 else
 123                         append(buf, ".", len);
 124
 125                 if (expr->member && expr->member->name)
 126                         append(buf, expr->member->name, len);
 127                 else
 128                         append(buf, "unknown_member", len);
 129
 130                 return;
 131         case EXPR_SYMBOL:
 132                 if (expr->symbol_name)
 133                         append(buf, expr->symbol_name->name, len);
 134                 if (sym_ptr) {
 135                         if (*sym_ptr)
 136                                 *complicated = 1;
 137                         *sym_ptr = expr->symbol;
 138                 }
 139                 return;
 140         case EXPR_PREOP: {
 141                 const char *tmp;
 142
 143                 if (get_expression_statement(expr)) {
 144                         *complicated = 2;
 145                         return;
 146                 }
 147
 148                 if (expr->op == '(') {
 149                         if (!no_parens)
 150                                 append(buf, "(", len);
 151                 } else if (expr->op != '*' || !get_array_expr(expr->unop)) {
 152                         tmp = show_special(expr->op);
 153                         append(buf, tmp, len);
 154                 }
 155                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 156                                                  len, complicated, no_parens);
 157
 158                 if (expr->op == '(' && !no_parens)
 159                         append(buf, ")", len);
 160
 161                 if (expr->op == SPECIAL_DECREMENT ||
 162                                 expr->op == SPECIAL_INCREMENT ||
 163                                 expr->op == '&')
 164                         *complicated = 1;
 165
 166                 return;
 167         }
 168         case EXPR_POSTOP: {
 169                 const char *tmp;
 170
 171                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 172                                                  len, complicated, no_parens);
 173                 tmp = show_special(expr->op);
 174                 append(buf, tmp, len);
 175
 176                 if (expr->op == SPECIAL_DECREMENT || expr->op == SPECIAL_INCREMENT)
 177                         *complicated = 1;
 178                 return;
 179         }
 180         case EXPR_ASSIGNMENT:
 181         case EXPR_COMPARE:
 182         case EXPR_LOGICAL:
 183         case EXPR_BINOP: {
 184                 char tmp[10];
 185                 struct expression *array_expr;
 186
 187                 *complicated = 1;
 188                 array_expr = get_array_expr(expr);
 189                 if (array_expr) {
 190                         __get_variable_from_expr(sym_ptr, buf, array_expr, len, complicated, no_parens);
 191                         append(buf, "[", len);
 192                 } else {
 193                         __get_variable_from_expr(sym_ptr, buf, expr->left, len, complicated, no_parens);
 194                         snprintf(tmp, sizeof(tmp), " %s ", show_special(expr->op));
 195                         append(buf, tmp, len);
 196                 }
 197                 __get_variable_from_expr(NULL, buf, expr->right, len, complicated, no_parens);
 198                 if (array_expr)
 199                         append(buf, "]", len);
 200                 return;
 201         }
 202         case EXPR_VALUE: {
 203                 char tmp[25];
 204
 205                 *complicated = 1;
 206                 snprintf(tmp, 25, "%lld", expr->value);
 207                 append(buf, tmp, len);
 208                 return;
 209         }
 210         case EXPR_STRING:
 211                 append(buf, "\"", len);
 212                 append(buf, expr->string->data, len);
 213                 append(buf, "\"", len);
 214                 return;
 215         case EXPR_CALL: {
 216                 struct expression *tmp;
 217                 int i;
 218
 219                 *complicated = 1;
 220                 __get_variable_from_expr(NULL, buf, expr->fn, len, complicated, no_parens);
 221                 append(buf, "(", len);
 222                 i = 0;
 223                 FOR_EACH_PTR(expr->args, tmp) {
 224                         if (i++)
 225                                 append(buf, ", ", len);
 226                         __get_variable_from_expr(NULL, buf, tmp, len, complicated, no_parens);
 227                 } END_FOR_EACH_PTR(tmp);
 228                 append(buf, ")", len);
 229                 return;
 230         }
 231         case EXPR_CAST:
 232                 __get_variable_from_expr(sym_ptr, buf,
 233                                          expr->cast_expression, len,
 234                                          complicated, no_parens);
 235                 return;
 236         case EXPR_SIZEOF: {
 237                 int size;
 238                 char tmp[25];
 239
 240                 if (expr->cast_type && get_base_type(expr->cast_type)) {
 241                         size = (get_base_type(expr->cast_type))->bit_size;
 242                         snprintf(tmp, 25, "%d", bits_to_bytes(size));
 243                         append(buf, tmp, len);
 244                 }
 245                 return;
 246         }
 247         case EXPR_IDENTIFIER:
 248                 *complicated = 1;
 249                 if (expr->expr_ident && expr->expr_ident->name)
 250                         append(buf, expr->expr_ident->name, len);
 251                 return;
 252         default:
 253                 *complicated = 1;
 254                 //printf("unknown type = %d\n", expr->type);
 255                 return;
 256         }
 257 }
 258
 259 /*
 260  * This is returns a stylized "c looking" representation of the
 261  * variable name.
 262  *
 263  * It uses the same buffer every time so you have to save the result
 264  * yourself if you want to keep it.
 265  *
 266  */
 267
 268 char *expr_to_str_sym(struct expression *expr, struct symbol **sym_ptr)
 269 {
 270         static char var_name[VAR_LEN];
 271         int complicated = 0;
 272
 273         if (sym_ptr)
 274                 *sym_ptr = NULL;
 275         var_name[0] = '\0';
 276
 277         if (!expr)
 278                 return NULL;
 279         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 280                                  &complicated, 0);
 281         if (complicated < 2)
 282                 return alloc_string(var_name);
 283         else
 284                 return NULL;
 285 }
 286
 287 char *expr_to_str(struct expression *expr)
 288 {
 289         return expr_to_str_sym(expr, NULL);
 290 }
 291
 292 /*
 293  * get_variable_from_expr_simple() only returns simple variables.
 294  * If it's a complicated variable like a->foo[x] instead of just 'a->foo'
 295  * then it returns NULL.
 296  */
 297 char *expr_to_var_sym(struct expression *expr,
 298                                     struct symbol **sym_ptr)
 299 {
 300         static char var_name[VAR_LEN];
 301         int complicated = 0;
 302
 303         if (sym_ptr)
 304                 *sym_ptr = NULL;
 305         var_name[0] = '\0';
 306
 307         if (!expr)
 308                 return NULL;
 309         expr = strip_expr(expr);
 310         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 311                                  &complicated, 1);
 312
 313         if (complicated) {
 314                 if (sym_ptr)
 315                         *sym_ptr = NULL;
 316                 return NULL;
 317         }
 318         return alloc_string(var_name);
 319 }
 320
 321 char *expr_to_var(struct expression *expr)
 322 {
 323         return expr_to_var_sym(expr, NULL);
 324 }
 325
 326 int sym_name_is(const char *name, struct expression *expr)
 327 {
 328         if (!expr)
 329                 return 0;
 330         if (expr->type != EXPR_SYMBOL)
 331                 return 0;
 332         if (!strcmp(expr->symbol_name->name, name))
 333                 return 1;
 334         return 0;
 335 }
 336
 337 int is_zero(struct expression *expr)
 338 {
 339         sval_t sval;
 340
 341         if (get_value(expr, &sval) && sval.value == 0)
 342                 return 1;
 343         return 0;
 344 }
 345
 346 int is_array(struct expression *expr)
 347 {
 348         expr = strip_expr(expr);
 349         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 350                 return 0;
 351         expr = expr->unop;
 352         if (expr->op != '+')
 353                 return 0;
 354         return 1;
 355 }
 356
 357 struct expression *get_array_name(struct expression *expr)
 358 {
 359         if (!is_array(expr))
 360                 return NULL;
 361         return strip_expr(expr->unop->left);
 362 }
 363
 364 struct expression *get_array_offset(struct expression *expr)
 365 {
 366         if (!is_array(expr))
 367                 return NULL;
 368         return expr->unop->right;
 369 }
 370
 371 const char *show_state(struct smatch_state *state)
 372 {
 373         if (!state)
 374                 return NULL;
 375         return state->name;
 376 }
 377
 378 struct statement *get_expression_statement(struct expression *expr)
 379 {
 380         /* What are those things called? if (({....; ret;})) { ...*/
 381
 382         if (expr->type != EXPR_PREOP)
 383                 return NULL;
 384         if (expr->op != '(')
 385                 return NULL;
 386         if (expr->unop->type != EXPR_STATEMENT)
 387                 return NULL;
 388         if (expr->unop->statement->type != STMT_COMPOUND)
 389                 return NULL;
 390         return expr->unop->statement;
 391 }
 392
 393 struct expression *strip_parens(struct expression *expr)
 394 {
 395         if (!expr)
 396                 return NULL;
 397
 398         if (expr->type == EXPR_PREOP) {
 399                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 400                         expr->unop->statement->type == STMT_COMPOUND)
 401                         return expr;
 402                 if (expr->op == '(')
 403                         return strip_parens(expr->unop);
 404         }
 405         return expr;
 406 }
 407
 408 struct expression *strip_expr(struct expression *expr)
 409 {
 410         if (!expr)
 411                 return NULL;
 412
 413         switch (expr->type) {
 414         case EXPR_FORCE_CAST:
 415         case EXPR_CAST:
 416                 return strip_expr(expr->cast_expression);
 417         case EXPR_PREOP:
 418                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 419                         expr->unop->statement->type == STMT_COMPOUND)
 420                         return expr;
 421                 if (expr->op == '(')
 422                         return strip_expr(expr->unop);
 423         }
 424         return expr;
 425 }
 426
 427 static void delete_state_tracker(struct tracker *t)
 428 {
 429         delete_state(t->owner, t->name, t->sym);
 430         __free_tracker(t);
 431 }
 432
 433 void scoped_state(int my_id, const char *name, struct symbol *sym)
 434 {
 435         struct tracker *t;
 436
 437         t = alloc_tracker(my_id, name, sym);
 438         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 439 }
 440
 441 int is_error_return(struct expression *expr)
 442 {
 443         struct symbol *cur_func = cur_func_sym;
 444         sval_t sval;
 445
 446         if (!expr)
 447                 return 0;
 448         if (cur_func->type != SYM_NODE)
 449                 return 0;
 450         cur_func = get_base_type(cur_func);
 451         if (cur_func->type != SYM_FN)
 452                 return 0;
 453         cur_func = get_base_type(cur_func);
 454         if (cur_func == &void_ctype)
 455                 return 0;
 456         if (!get_implied_value(expr, &sval))
 457                 return 0;
 458         if (sval.value < 0)
 459                 return 1;
 460         if (cur_func->type == SYM_PTR && sval.value == 0)
 461                 return 1;
 462         return 0;
 463 }
 464
 465 int getting_address(void)
 466 {
 467         struct expression *tmp;
 468         int i = 0;
 469         int dot_ops = 0;
 470
 471         FOR_EACH_PTR_REVERSE(big_expression_stack, tmp) {
 472                 if (!i++)
 473                         continue;
 474                 if (tmp->type == EXPR_PREOP && tmp->op == '(')
 475                         continue;
 476                 if (tmp->op == '.' && !dot_ops++)
 477                         continue;
 478                 if (tmp->op == '&')
 479                         return 1;
 480                 return 0;
 481         } END_FOR_EACH_PTR_REVERSE(tmp);
 482         return 0;
 483 }
 484
 485 char *get_member_name(struct expression *expr)
 486 {
 487         char buf[256];
 488         struct symbol *sym;
 489
 490         expr = strip_expr(expr);
 491         if (expr->type != EXPR_DEREF)
 492                 return NULL;
 493         sym = get_type(expr->deref);
 494         if (!sym)
 495                 return NULL;
 496         /* FIXME: HACK! Sparse isn't storing the names of unions...  Just take last member */
 497         if (sym->type == SYM_UNION) {
 498                 struct symbol *tmp;
 499
 500                 FOR_EACH_PTR_REVERSE(sym->symbol_list, tmp) {
 501                         if (tmp->ident) {
 502                                 const char *member_name;
 503
 504                                 if (expr->member)
 505                                         member_name = expr->member->name;
 506                                 else
 507                                         member_name = "unknown_member";
 508                                 snprintf(buf, sizeof(buf), "(union hack %s)->%s", tmp->ident->name, member_name);
 509                                 return alloc_string(buf);
 510                         }
 511                 } END_FOR_EACH_PTR_REVERSE(tmp);
 512                 return NULL;
 513         }
 514         if (!sym->ident)
 515                 return NULL;
 516         snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, expr->member->name);
 517         return alloc_string(buf);
 518 }
 519
 520 int positions_eq(struct position pos1, struct position pos2)
 521 {
 522         if (pos1.line != pos2.line)
 523                 return 0;
 524         if (pos1.pos != pos2.pos)
 525                 return 0;
 526         if (pos1.stream != pos2.stream)
 527                 return 0;
 528         return 1;
 529 }
 530
 531 struct statement *get_current_statement(void)
 532 {
 533         struct statement *prev, *tmp;
 534
 535         prev = last_ptr_list((struct ptr_list *)big_statement_stack);
 536
 537         if (!prev || !get_macro_name(prev->pos))
 538                 return prev;
 539
 540         FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
 541                 if (positions_eq(tmp->pos, prev->pos))
 542                         continue;
 543                 if (prev->pos.line > tmp->pos.line)
 544                         return prev;
 545                 return tmp;
 546         } END_FOR_EACH_PTR_REVERSE(tmp);
 547         return prev;
 548 }
 549
 550 int get_param_num_from_sym(struct symbol *sym)
 551 {
 552         struct symbol *tmp;
 553         int i;
 554
 555         if (!cur_func_sym)
 556                 return -1;
 557
 558         i = 0;
 559         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, tmp) {
 560                 if (tmp == sym)
 561                         return i;
 562                 i++;
 563         } END_FOR_EACH_PTR(tmp);
 564         return -1;
 565 }
 566
 567 int ms_since(struct timeval *start)
 568 {
 569         struct timeval end;
 570         double diff;
 571
 572         gettimeofday(&end, NULL);
 573         diff = (end.tv_sec - start->tv_sec) * 1000.0;
 574         diff += (end.tv_usec - start->tv_usec) / 1000.0;
 575         return (int)diff;
 576 }
 577