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