smatch_expressions.c

   1 #include "smatch.h"
   2 #include "smatch_extra.h"
   3
   4 DECLARE_ALLOCATOR(sname);
   5 __ALLOCATOR(struct expression, "temporary expr", tmp_expression);
   6
   7 static struct position get_cur_pos(void)
   8 {
   9         static struct position pos;
  10         static struct position none;
  11         struct expression *expr;
  12         struct statement *stmt;
  13
  14         expr = last_ptr_list((struct ptr_list *)big_expression_stack);
  15         stmt = last_ptr_list((struct ptr_list *)big_statement_stack);
  16         if (expr)
  17                 pos = expr->pos;
  18         else if (stmt)
  19                 pos = stmt->pos;
  20         else
  21                 pos = none;
  22         return pos;
  23 }
  24
  25 struct expression *alloc_tmp_expression(struct position pos, int type)
  26 {
  27         struct expression *expr;
  28
  29         expr = __alloc_tmp_expression(0);
  30         expr->smatch_flags |= Tmp;
  31         expr->type = type;
  32         expr->pos = pos;
  33         return expr;
  34 }
  35
  36 void free_tmp_expressions(void)
  37 {
  38         clear_tmp_expression_alloc();
  39 }
  40
  41 struct expression *zero_expr(void)
  42 {
  43         struct expression *zero;
  44
  45         zero = alloc_tmp_expression(get_cur_pos(), EXPR_VALUE);
  46         zero->value = 0;
  47         zero->ctype = &int_ctype;
  48         return zero;
  49 }
  50
  51 struct expression *value_expr(long long val)
  52 {
  53         struct expression *expr;
  54
  55         if (!val)
  56                 return zero_expr();
  57
  58         expr = alloc_tmp_expression(get_cur_pos(), EXPR_VALUE);
  59         expr->value = val;
  60         expr->ctype = &llong_ctype;
  61         return expr;
  62 }
  63
  64 struct expression *member_expression(struct expression *deref, int op, struct ident *member)
  65 {
  66         struct expression *expr;
  67
  68         expr = alloc_tmp_expression(deref->pos, EXPR_DEREF);
  69         expr->op = op;
  70         expr->deref = deref;
  71         expr->member = member;
  72         expr->member_offset = -1;
  73         return expr;
  74 }
  75
  76 struct expression *preop_expression(struct expression *expr, int op)
  77 {
  78         struct expression *preop;
  79
  80         preop = alloc_tmp_expression(expr->pos, EXPR_PREOP);
  81         preop->unop = expr;
  82         preop->op = op;
  83         return preop;
  84 }
  85
  86 struct expression *deref_expression(struct expression *expr)
  87 {
  88         if (expr->type == EXPR_BINOP)
  89                 expr = preop_expression(expr, '(');
  90         return preop_expression(expr, '*');
  91 }
  92
  93 struct expression *assign_expression(struct expression *left, int op, struct expression *right)
  94 {
  95         struct expression *expr;
  96
  97         if (!right)
  98                 return NULL;
  99
 100         /* FIXME: make this a tmp expression. */
 101         expr = alloc_expression(right->pos, EXPR_ASSIGNMENT);
 102         expr->op = op;
 103         expr->left = left;
 104         expr->right = right;
 105         return expr;
 106 }
 107
 108 struct expression *binop_expression(struct expression *left, int op, struct expression *right)
 109 {
 110         struct expression *expr;
 111
 112         expr = alloc_tmp_expression(right->pos, EXPR_BINOP);
 113         expr->op = op;
 114         expr->left = left;
 115         expr->right = right;
 116         return expr;
 117 }
 118
 119 struct expression *array_element_expression(struct expression *array, struct expression *offset)
 120 {
 121         struct expression *expr;
 122
 123         expr = binop_expression(array, '+', offset);
 124         return deref_expression(expr);
 125 }
 126
 127 struct expression *symbol_expression(struct symbol *sym)
 128 {
 129         struct expression *expr;
 130
 131         expr = alloc_tmp_expression(sym->pos, EXPR_SYMBOL);
 132         expr->symbol = sym;
 133         expr->symbol_name = sym->ident;
 134         return expr;
 135 }
 136
 137 struct expression *compare_expression(struct expression *left, int op, struct expression *right)
 138 {
 139         struct expression *expr;
 140
 141         expr = alloc_tmp_expression(get_cur_pos(), EXPR_COMPARE);
 142         expr->op = op;
 143         expr->left = left;
 144         expr->right = right;
 145         return expr;
 146 }
 147
 148 struct expression *gen_string_expression(char *str)
 149 {
 150         struct expression *ret;
 151         struct string *string;
 152         int len;
 153
 154         len = strlen(str) + 1;
 155         string = (void *)__alloc_sname(4 + len);
 156         string->length = len;
 157         string->immutable = 0;
 158         memcpy(string->data, str, len);
 159
 160         ret = alloc_tmp_expression(get_cur_pos(), EXPR_STRING);
 161         ret->wide = 0;
 162         ret->string = string;
 163
 164         return ret;
 165 }
 166
 167 struct expression *call_expression(struct expression *fn, struct expression_list *args)
 168 {
 169         struct expression *expr;
 170
 171         expr = alloc_tmp_expression(fn->pos, EXPR_CALL);
 172         expr->fn = fn;
 173         expr->args = args;
 174
 175         return expr;
 176 }
 177
 178 static struct expression *get_expression_from_base_and_str(struct expression *base, const char *addition)
 179 {
 180         struct expression *ret = NULL;
 181         struct token *token, *prev, *end;
 182         char *alloc;
 183
 184         if (addition[0] == '\0')
 185                 return base;
 186
 187         alloc = alloc_string_newline(addition);
 188
 189         token = tokenize_buffer(alloc, strlen(alloc), &end);
 190         if (!token)
 191                 goto free;
 192         if (token_type(token) != TOKEN_STREAMBEGIN)
 193                 goto free;
 194         token = token->next;
 195
 196         ret = base;
 197         while (token_type(token) == TOKEN_SPECIAL &&
 198                (token->special == SPECIAL_DEREFERENCE || token->special == '.')) {
 199                 prev = token;
 200                 token = token->next;
 201                 if (token_type(token) != TOKEN_IDENT)
 202                         goto free;
 203                 switch (prev->special) {
 204                 case SPECIAL_DEREFERENCE:
 205                         ret = deref_expression(ret);
 206                         ret = member_expression(ret, '*', token->ident);
 207                         break;
 208                 case '.':
 209                         ret = member_expression(ret, '.', token->ident);
 210                         break;
 211                 default:
 212                         goto free;
 213                 }
 214                 token = token->next;
 215         }
 216
 217         if (token_type(token) != TOKEN_STREAMEND)
 218                 goto free;
 219
 220 free:
 221         free_string(alloc);
 222
 223         return ret;
 224 }
 225
 226 static struct expression *gen_expression_from_name_sym_helper(const char *name, struct symbol *sym)
 227 {
 228         struct expression *ret;
 229         int skip = 0;
 230
 231         if (name[0] == '&' ||
 232             name[0] == '*' ||
 233             name[0] == '(') {
 234                 ret = gen_expression_from_name_sym_helper(name + 1, sym);
 235                 return preop_expression(ret, name[0]);
 236         }
 237         while (name[skip] != '\0' && name[skip] != '.' && name[skip] != '-')
 238                 skip++;
 239
 240         return get_expression_from_base_and_str(symbol_expression(sym), name + skip);
 241 }
 242
 243 struct expression *gen_expression_from_name_sym(const char *name, struct symbol *sym)
 244 {
 245         struct expression *ret;
 246
 247         ret = gen_expression_from_name_sym_helper(name, sym);
 248         if (ret) {
 249                 char *new = expr_to_str(ret);
 250
 251                 /*
 252                  * FIXME: this sometimes changes "foo->bar.a.b->c" into
 253                  * "foo->bar.a.b.c".  I don't know why...  :(
 254                  *
 255                  */
 256                 if (!new || strcmp(name, new) != 0)
 257                         return NULL;
 258         }
 259         return ret;
 260 }
 261
 262 struct expression *gen_expression_from_key(struct expression *arg, const char *key)
 263 {
 264         struct expression *ret;
 265         struct token *token, *prev, *end;
 266         const char *p = key;
 267         char buf[4095];
 268         char *alloc;
 269         size_t len;
 270
 271         /* The idea is that we can parse either $0->foo or $->foo */
 272         if (key[0] != '$')
 273                 return NULL;
 274         p++;
 275         while (*p >= '0' && *p <= '9')
 276                 p++;
 277         len = snprintf(buf, sizeof(buf), "%s\n", p);
 278         alloc = alloc_string(buf);
 279
 280         token = tokenize_buffer(alloc, len, &end);
 281         if (!token)
 282                 return NULL;
 283         if (token_type(token) != TOKEN_STREAMBEGIN)
 284                 return NULL;
 285         token = token->next;
 286
 287         ret = arg;
 288         while (token_type(token) == TOKEN_SPECIAL &&
 289                (token->special == SPECIAL_DEREFERENCE || token->special == '.')) {
 290                 prev = token;
 291                 token = token->next;
 292                 if (token_type(token) != TOKEN_IDENT)
 293                         return NULL;
 294                 ret = deref_expression(ret);
 295                 ret = member_expression(ret,
 296                                         (prev->special == SPECIAL_DEREFERENCE) ? '*' : '.',
 297                                         token->ident);
 298                 token = token->next;
 299         }
 300
 301         if (token_type(token) != TOKEN_STREAMEND)
 302                 return NULL;
 303
 304         return ret;
 305 }
 306
 307 struct expression *gen_expr_from_param_key(struct expression *expr, int param, const char *key)
 308 {
 309         struct expression *ret = NULL;
 310         struct symbol *sym;
 311         char *name;
 312
 313         name = get_name_sym_from_key(expr, param, key, &sym);
 314         if (!name || !sym)
 315                 goto free;
 316
 317         ret = gen_expression_from_name_sym(name, sym);
 318 free:
 319         free_string(name);
 320         return ret;
 321 }
 322
 323 bool is_fake_var(struct expression *expr)
 324 {
 325         if (expr && (expr->smatch_flags & Fake))
 326                 return true;
 327         return false;
 328 }
 329
 330 struct expression *fake_variable(struct symbol *type, const char *name)
 331 {
 332         struct symbol *sym, *node;
 333         struct expression *ret;
 334         struct ident *ident;
 335
 336         if (!type)
 337                 type = &llong_ctype;
 338
 339         ident = alloc_ident(name, strlen(name));
 340
 341         sym = alloc_symbol(get_cur_pos(), type->type);
 342         sym->ident = ident;
 343         sym->ctype.base_type = type;
 344         sym->ctype.modifiers |= MOD_AUTO;
 345
 346         node = alloc_symbol(get_cur_pos(), SYM_NODE);
 347         node->ident = ident;
 348         node->ctype.base_type = type;
 349         node->ctype.modifiers |= MOD_AUTO;
 350
 351         ret = symbol_expression(node);
 352         ret->smatch_flags |= Fake;
 353
 354         return ret;
 355 }
 356
 357 void expr_set_parent_expr(struct expression *expr, struct expression *parent)
 358 {
 359         if (!expr)
 360                 return;
 361         if (parent && parent->smatch_flags & Tmp)
 362                 return;
 363
 364         expr->parent = (unsigned long)parent | 0x1UL;
 365 }
 366
 367 void expr_set_parent_stmt(struct expression *expr, struct statement *parent)
 368 {
 369         if (!expr)
 370                 return;
 371         expr->parent = (unsigned long)parent;
 372 }
 373
 374 struct expression *expr_get_parent_expr(struct expression *expr)
 375 {
 376         struct expression *parent;
 377
 378         if (!expr)
 379                 return NULL;
 380         if (!(expr->parent & 0x1UL))
 381                 return NULL;
 382
 383         parent = (struct expression *)(expr->parent & ~0x1UL);
 384         if (parent && (parent->smatch_flags & Fake))
 385                 return expr_get_parent_expr(parent);
 386         return parent;
 387 }
 388
 389 struct expression *expr_get_fake_parent_expr(struct expression *expr)
 390 {
 391         struct expression *parent;
 392
 393         if (!expr)
 394                 return NULL;
 395         if (!(expr->parent & 0x1UL))
 396                 return NULL;
 397
 398         parent = (struct expression *)(expr->parent & ~0x1UL);
 399         if (parent && (parent->smatch_flags & Fake))
 400                 return parent;
 401         return NULL;
 402 }
 403
 404 struct statement *expr_get_parent_stmt(struct expression *expr)
 405 {
 406         if (!expr)
 407                 return NULL;
 408         if (expr->parent & 0x1UL)
 409                 return NULL;
 410         return (struct statement *)expr->parent;
 411 }
 412