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 static 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                 append(buf, expr->member->name, len);
 126
 127                 return;
 128         case EXPR_SYMBOL:
 129                 if (expr->symbol_name)
 130                         append(buf, expr->symbol_name->name, len);
 131                 if (sym_ptr) {
 132                         if (*sym_ptr)
 133                                 *complicated = 1;
 134                         *sym_ptr = expr->symbol;
 135                 }
 136                 return;
 137         case EXPR_PREOP: {
 138                 const char *tmp;
 139
 140                 if (get_expression_statement(expr)) {
 141                         *complicated = 2;
 142                         return;
 143                 }
 144
 145                 if (expr->op == '(') {
 146                         if (!no_parens)
 147                                 append(buf, "(", len);
 148                 } else if (expr->op != '*' || !get_array_expr(expr->unop)) {
 149                         tmp = show_special(expr->op);
 150                         append(buf, tmp, len);
 151                 }
 152                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 153                                                  len, complicated, no_parens);
 154
 155                 if (expr->op == '(' && !no_parens)
 156                         append(buf, ")", len);
 157
 158                 if (expr->op == SPECIAL_DECREMENT ||
 159                                 expr->op == SPECIAL_INCREMENT ||
 160                                 expr->op == '&')
 161                         *complicated = 1;
 162
 163                 return;
 164         }
 165         case EXPR_POSTOP: {
 166                 const char *tmp;
 167
 168                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 169                                                  len, complicated, no_parens);
 170                 tmp = show_special(expr->op);
 171                 append(buf, tmp, len);
 172
 173                 if (expr->op == SPECIAL_DECREMENT || expr->op == SPECIAL_INCREMENT)
 174                         *complicated = 1;
 175                 return;
 176         }
 177         case EXPR_ASSIGNMENT:
 178         case EXPR_COMPARE:
 179         case EXPR_LOGICAL:
 180         case EXPR_BINOP: {
 181                 char tmp[10];
 182                 struct expression *array_expr;
 183
 184                 *complicated = 1;
 185                 array_expr = get_array_expr(expr);
 186                 if (array_expr) {
 187                         __get_variable_from_expr(sym_ptr, buf, array_expr, len, complicated, no_parens);
 188                         append(buf, "[", len);
 189                 } else {
 190                         __get_variable_from_expr(sym_ptr, buf, expr->left, len, complicated, no_parens);
 191                         snprintf(tmp, sizeof(tmp), " %s ", show_special(expr->op));
 192                         append(buf, tmp, len);
 193                 }
 194                 __get_variable_from_expr(NULL, buf, expr->right, len, complicated, no_parens);
 195                 if (array_expr)
 196                         append(buf, "]", len);
 197                 return;
 198         }
 199         case EXPR_VALUE: {
 200                 char tmp[25];
 201
 202                 *complicated = 1;
 203                 snprintf(tmp, 25, "%lld", expr->value);
 204                 append(buf, tmp, len);
 205                 return;
 206         }
 207         case EXPR_STRING:
 208                 append(buf, "\"", len);
 209                 append(buf, expr->string->data, len);
 210                 append(buf, "\"", len);
 211                 return;
 212         case EXPR_CALL: {
 213                 struct expression *tmp;
 214                 int i;
 215
 216                 *complicated = 1;
 217                 __get_variable_from_expr(NULL, buf, expr->fn, len, complicated, no_parens);
 218                 append(buf, "(", len);
 219                 i = 0;
 220                 FOR_EACH_PTR(expr->args, tmp) {
 221                         if (i++)
 222                                 append(buf, ", ", len);
 223                         __get_variable_from_expr(NULL, buf, tmp, len, complicated, no_parens);
 224                 } END_FOR_EACH_PTR(tmp);
 225                 append(buf, ")", len);
 226                 return;
 227         }
 228         case EXPR_CAST:
 229                 __get_variable_from_expr(sym_ptr, buf,
 230                                          expr->cast_expression, len,
 231                                          complicated, no_parens);
 232                 return;
 233         case EXPR_SIZEOF: {
 234                 int size;
 235                 char tmp[25];
 236
 237                 if (expr->cast_type && get_base_type(expr->cast_type)) {
 238                         size = (get_base_type(expr->cast_type))->bit_size;
 239                         snprintf(tmp, 25, "%d", bits_to_bytes(size));
 240                         append(buf, tmp, len);
 241                 }
 242                 return;
 243         }
 244         default:
 245                 *complicated = 1;
 246                 //printf("unknown type = %d\n", expr->type);
 247                 return;
 248         }
 249 }
 250
 251 /*
 252  * This is returns a stylized "c looking" representation of the
 253  * variable name.
 254  *
 255  * It uses the same buffer every time so you have to save the result
 256  * yourself if you want to keep it.
 257  *
 258  */
 259
 260 char *expr_to_str_sym(struct expression *expr, struct symbol **sym_ptr)
 261 {
 262         static char var_name[VAR_LEN];
 263         int complicated = 0;
 264
 265         if (sym_ptr)
 266                 *sym_ptr = NULL;
 267         var_name[0] = '\0';
 268
 269         if (!expr)
 270                 return NULL;
 271         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 272                                  &complicated, 0);
 273         if (complicated < 2)
 274                 return alloc_string(var_name);
 275         else
 276                 return NULL;
 277 }
 278
 279 char *expr_to_str(struct expression *expr)
 280 {
 281         return expr_to_str_sym(expr, NULL);
 282 }
 283
 284 /*
 285  * get_variable_from_expr_simple() only returns simple variables.
 286  * If it's a complicated variable like a->foo[x] instead of just 'a->foo'
 287  * then it returns NULL.
 288  */
 289 char *expr_to_var_sym(struct expression *expr,
 290                                     struct symbol **sym_ptr)
 291 {
 292         static char var_name[VAR_LEN];
 293         int complicated = 0;
 294
 295         if (sym_ptr)
 296                 *sym_ptr = NULL;
 297         var_name[0] = '\0';
 298
 299         if (!expr)
 300                 return NULL;
 301         expr = strip_expr(expr);
 302         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 303                                  &complicated, 1);
 304
 305         if (complicated) {
 306                 if (sym_ptr)
 307                         *sym_ptr = NULL;
 308                 return NULL;
 309         }
 310         return alloc_string(var_name);
 311 }
 312
 313 char *expr_to_var(struct expression *expr)
 314 {
 315         return expr_to_var_sym(expr, NULL);
 316 }
 317
 318 int sym_name_is(const char *name, struct expression *expr)
 319 {
 320         if (!expr)
 321                 return 0;
 322         if (expr->type != EXPR_SYMBOL)
 323                 return 0;
 324         if (!strcmp(expr->symbol_name->name, name))
 325                 return 1;
 326         return 0;
 327 }
 328
 329 int is_zero(struct expression *expr)
 330 {
 331         sval_t sval;
 332
 333         if (get_value(expr, &sval) && sval.value == 0)
 334                 return 1;
 335         return 0;
 336 }
 337
 338 int is_array(struct expression *expr)
 339 {
 340         expr = strip_expr(expr);
 341         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 342                 return 0;
 343         expr = expr->unop;
 344         if (expr->op != '+')
 345                 return 0;
 346         return 1;
 347 }
 348
 349 struct expression *get_array_name(struct expression *expr)
 350 {
 351         if (!is_array(expr))
 352                 return NULL;
 353         return strip_expr(expr->unop->left);
 354 }
 355
 356 struct expression *get_array_offset(struct expression *expr)
 357 {
 358         if (!is_array(expr))
 359                 return NULL;
 360         return expr->unop->right;
 361 }
 362
 363 const char *show_state(struct smatch_state *state)
 364 {
 365         if (!state)
 366                 return NULL;
 367         return state->name;
 368 }
 369
 370 struct statement *get_expression_statement(struct expression *expr)
 371 {
 372         /* What are those things called? if (({....; ret;})) { ...*/
 373
 374         if (expr->type != EXPR_PREOP)
 375                 return NULL;
 376         if (expr->op != '(')
 377                 return NULL;
 378         if (expr->unop->type != EXPR_STATEMENT)
 379                 return NULL;
 380         if (expr->unop->statement->type != STMT_COMPOUND)
 381                 return NULL;
 382         return expr->unop->statement;
 383 }
 384
 385 struct expression *strip_parens(struct expression *expr)
 386 {
 387         if (!expr)
 388                 return NULL;
 389
 390         if (expr->type == EXPR_PREOP) {
 391                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 392                         expr->unop->statement->type == STMT_COMPOUND)
 393                         return expr;
 394                 if (expr->op == '(')
 395                         return strip_parens(expr->unop);
 396         }
 397         return expr;
 398 }
 399
 400 struct expression *strip_expr(struct expression *expr)
 401 {
 402         if (!expr)
 403                 return NULL;
 404
 405         switch (expr->type) {
 406         case EXPR_FORCE_CAST:
 407         case EXPR_CAST:
 408                 return strip_expr(expr->cast_expression);
 409         case EXPR_PREOP:
 410                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 411                         expr->unop->statement->type == STMT_COMPOUND)
 412                         return expr;
 413                 if (expr->op == '(')
 414                         return strip_expr(expr->unop);
 415         }
 416         return expr;
 417 }
 418
 419 static void delete_state_tracker(struct tracker *t)
 420 {
 421         delete_state(t->owner, t->name, t->sym);
 422         __free_tracker(t);
 423 }
 424
 425 void scoped_state(int my_id, const char *name, struct symbol *sym)
 426 {
 427         struct tracker *t;
 428
 429         t = alloc_tracker(my_id, name, sym);
 430         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 431 }
 432
 433 int is_error_return(struct expression *expr)
 434 {
 435         struct symbol *cur_func = cur_func_sym;
 436         sval_t sval;
 437
 438         if (!expr)
 439                 return 0;
 440         if (cur_func->type != SYM_NODE)
 441                 return 0;
 442         cur_func = get_base_type(cur_func);
 443         if (cur_func->type != SYM_FN)
 444                 return 0;
 445         cur_func = get_base_type(cur_func);
 446         if (cur_func == &void_ctype)
 447                 return 0;
 448         if (!get_value(expr, &sval))
 449                 return 0;
 450         if (sval_cmp_val(sval, 0) < 0)
 451                 return 1;
 452         if (cur_func->type == SYM_PTR && sval.value == 0)
 453                 return 1;
 454         return 0;
 455 }
 456
 457 int getting_address(void)
 458 {
 459         struct expression *tmp;
 460         int i = 0;
 461         int dot_ops = 0;
 462
 463         FOR_EACH_PTR_REVERSE(big_expression_stack, tmp) {
 464                 if (!i++)
 465                         continue;
 466                 if (tmp->type == EXPR_PREOP && tmp->op == '(')
 467                         continue;
 468                 if (tmp->op == '.' && !dot_ops++)
 469                         continue;
 470                 if (tmp->op == '&')
 471                         return 1;
 472                 return 0;
 473         } END_FOR_EACH_PTR_REVERSE(tmp);
 474         return 0;
 475 }
 476
 477 char *get_member_name(struct expression *expr)
 478 {
 479         char buf[256];
 480         struct symbol *sym;
 481
 482         expr = strip_expr(expr);
 483         if (expr->type != EXPR_DEREF)
 484                 return NULL;
 485         sym = get_type(expr->deref);
 486         if (!sym || !sym->ident)
 487                 return NULL;
 488         snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, expr->member->name);
 489         return alloc_string(buf);
 490 }
 491
 492 int positions_eq(struct position pos1, struct position pos2)
 493 {
 494         if (pos1.line != pos2.line)
 495                 return 0;
 496         if (pos1.pos != pos2.pos)
 497                 return 0;
 498         if (pos1.stream != pos2.stream)
 499                 return 0;
 500         return 1;
 501 }
 502
 503 struct statement *get_current_statement(void)
 504 {
 505         struct statement *prev, *tmp;
 506
 507         prev = last_ptr_list((struct ptr_list *)big_statement_stack);
 508
 509         if (!prev || !get_macro_name(prev->pos))
 510                 return prev;
 511
 512         FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
 513                 if (positions_eq(tmp->pos, prev->pos))
 514                         continue;
 515                 if (prev->pos.line > tmp->pos.line)
 516                         return prev;
 517                 return tmp;
 518         } END_FOR_EACH_PTR_REVERSE(tmp);
 519         return prev;
 520 }
 521
 522 int get_param_num_from_sym(struct symbol *sym)
 523 {
 524         struct symbol *tmp;
 525         int i;
 526
 527         if (!cur_func_sym)
 528                 return -1;
 529
 530         i = 0;
 531         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, tmp) {
 532                 if (tmp == sym)
 533                         return i;
 534                 i++;
 535         } END_FOR_EACH_PTR(tmp);
 536         return -1;
 537 }
 538
 539 int ms_since(struct timeval *start)
 540 {
 541         struct timeval end;
 542         double diff;
 543
 544         gettimeofday(&end, NULL);
 545         diff = (end.tv_sec - start->tv_sec) * 1000.0;
 546         diff += (end.tv_usec - start->tv_usec) / 1000.0;
 547         return (int)diff;
 548 }
 549