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