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