smatch_sval.c

   1 /*
   2  * smatch/smatch_sval.c
   3  *
   4  * Copyright (C) 2012 Oracle.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  *
   9  * Basically the point of sval is that it can hold both ULLONG_MAX and
  10  * LLONG_MIN.  If it is an unsigned type then we use sval.uvalue or if it is
  11  * signed we use sval.value.
  12  *
  13  * I considered just using one bit to store whether the value was signed vs
  14  * unsigned but I think it might help to have the type information so we know
  15  * how to do type promotion.
  16  *
  17  */
  18
  19 #include "smatch.h"
  20 #include "smatch_slist.h"
  21 #include "smatch_extra.h"
  22
  23 __ALLOCATOR(sval_t, "svals", sval);
  24
  25 sval_t *sval_alloc(sval_t sval)
  26 {
  27         sval_t *ret;
  28
  29         ret = __alloc_sval(0);
  30         *ret = sval;
  31         return ret;
  32 }
  33
  34 sval_t *sval_alloc_permanent(sval_t sval)
  35 {
  36         sval_t *ret;
  37
  38         ret = malloc(sizeof(*ret));
  39         *ret = sval;
  40         return ret;
  41 }
  42
  43 sval_t sval_blank(struct expression *expr)
  44 {
  45         sval_t ret;
  46
  47         ret.type = get_type(expr);
  48         if (!ret.type)
  49                 ret.type = &llong_ctype;
  50         ret.value = 123456789;
  51
  52         return ret;
  53 }
  54
  55 sval_t sval_type_val(struct symbol *type, long long val)
  56 {
  57         sval_t ret;
  58
  59         ret.type = type;
  60         ret.value = val;
  61         return ret;
  62 }
  63
  64 sval_t sval_from_val(struct expression *expr, long long val)
  65 {
  66         sval_t ret;
  67
  68         ret = sval_blank(expr);
  69         ret.value = val;
  70         ret = sval_cast(get_type(expr), ret);
  71
  72         return ret;
  73 }
  74
  75 int sval_unsigned(sval_t sval)
  76 {
  77         return type_unsigned(sval.type);
  78 }
  79
  80 int sval_signed(sval_t sval)
  81 {
  82         return !type_unsigned(sval.type);
  83 }
  84
  85 int sval_bits(sval_t sval)
  86 {
  87         return type_bits(sval.type);
  88 }
  89
  90 int sval_positive_bits(sval_t sval)
  91 {
  92         return type_positive_bits(sval.type);
  93 }
  94
  95 int sval_bits_used(sval_t sval)
  96 {
  97         int i;
  98
  99         for (i = 64; i >= 1; i--) {
 100                 if (sval.uvalue & (1ULL << (i - 1)))
 101                         return i;
 102         }
 103         return 0;
 104 }
 105
 106 int sval_is_negative(sval_t sval)
 107 {
 108         if (sval_cmp_val(sval, 0) < 0)
 109                 return 1;
 110         return 0;
 111 }
 112
 113 int sval_is_positive(sval_t sval)
 114 {
 115         return !sval_is_negative(sval);
 116 }
 117
 118 int sval_is_min(sval_t sval)
 119 {
 120         sval_t min = sval_type_min(sval.type);
 121
 122         if (sval_unsigned(sval)) {
 123                 if (sval.uvalue == 0)
 124                         return 1;
 125                 return 0;
 126         }
 127         /* return true for less than min as well */
 128         return (sval.value <= min.value);
 129 }
 130
 131 int sval_is_max(sval_t sval)
 132 {
 133         sval_t max = sval_type_max(sval.type);
 134
 135         if (sval_unsigned(sval))
 136                 return (sval.uvalue >= max.value);
 137         return (sval.value >= max.value);
 138 }
 139
 140 int sval_is_a_min(sval_t sval)
 141 {
 142         if (sval_signed(sval) && sval.value == SHRT_MIN)
 143                 return 1;
 144         if (sval_signed(sval) && sval.value == INT_MIN)
 145                 return 1;
 146         if (sval_signed(sval) && sval.value == LLONG_MIN)
 147                 return 1;
 148         return 0;
 149 }
 150
 151 int sval_is_a_max(sval_t sval)
 152 {
 153         if (sval.uvalue == SHRT_MAX)
 154                 return 1;
 155         if (sval.uvalue == INT_MAX)
 156                 return 1;
 157         if (sval.uvalue == LLONG_MAX)
 158                 return 1;
 159         if (sval.uvalue == USHRT_MAX)
 160                 return 1;
 161         if (sval.uvalue == UINT_MAX)
 162                 return 1;
 163         if (sval_unsigned(sval) && sval.uvalue == ULLONG_MAX)
 164                 return 1;
 165         return 0;
 166 }
 167
 168 /*
 169  * Returns -1 if one is smaller, 0 if they are the same and 1 if two is larger.
 170  */
 171 int sval_cmp(sval_t one, sval_t two)
 172 {
 173         struct symbol *type;
 174
 175         type = one.type;
 176         if (sval_positive_bits(two) > sval_positive_bits(one))
 177                 type = two.type;
 178         if (type_bits(type) < 31)
 179                 type = &int_ctype;
 180
 181         one = sval_cast(type, one);
 182         two = sval_cast(type, two);
 183
 184         if (type_unsigned(type)) {
 185                 if (one.uvalue < two.uvalue)
 186                         return -1;
 187                 if (one.uvalue == two.uvalue)
 188                         return 0;
 189                 return 1;
 190         }
 191         /* fix me handle type promotion and unsigned values */
 192         if (one.value < two.value)
 193                 return -1;
 194         if (one.value == two.value)
 195                 return 0;
 196         return 1;
 197 }
 198
 199 int sval_cmp_t(struct symbol *type, sval_t one, sval_t two)
 200 {
 201         sval_t one_cast, two_cast;
 202
 203         one_cast = sval_cast(type, one);
 204         two_cast = sval_cast(type, two);
 205         return sval_cmp(one_cast, two_cast);
 206 }
 207
 208 int sval_cmp_val(sval_t one, long long val)
 209 {
 210         sval_t sval;
 211
 212         sval = sval_type_val(&llong_ctype, val);
 213         return sval_cmp(one, sval);
 214 }
 215
 216 sval_t sval_cast(struct symbol *type, sval_t sval)
 217 {
 218         sval_t ret;
 219
 220         if (!type)
 221                 type = &llong_ctype;
 222
 223         ret.type = type;
 224         switch (sval_bits(ret)) {
 225         case 8:
 226                 if (sval_unsigned(ret))
 227                         ret.value = (long long)(unsigned char)sval.value;
 228                 else
 229                         ret.value = (long long)(char)sval.value;
 230                 break;
 231         case 16:
 232                 if (sval_unsigned(ret))
 233                         ret.value = (long long)(unsigned short)sval.value;
 234                 else
 235                         ret.value = (long long)(short)sval.value;
 236                 break;
 237         case 32:
 238                 if (sval_unsigned(ret))
 239                         ret.value = (long long)(unsigned int)sval.value;
 240                 else
 241                         ret.value = (long long)(int)sval.value;
 242                 break;
 243         default:
 244                 ret.value = sval.value;
 245         }
 246         return ret;
 247
 248 }
 249
 250 sval_t sval_preop(sval_t sval, int op)
 251 {
 252         switch (op) {
 253         case '!':
 254                 sval.value = !sval.value;
 255                 break;
 256         case '~':
 257                 sval.value = ~sval.value;
 258                 /* fixme: should probably cast this here */
 259                 break;
 260         case '-':
 261                 sval.value = -sval.value;
 262                 break;
 263         }
 264         return sval;
 265 }
 266
 267 static sval_t sval_binop_unsigned(struct symbol *type, sval_t left, int op, sval_t right)
 268 {
 269         sval_t ret;
 270
 271         ret.type = type;
 272         switch (op) {
 273         case '*':
 274                 ret.uvalue =  left.uvalue * right.uvalue;
 275                 break;
 276         case '/':
 277                 if (right.uvalue == 0) {
 278                         sm_msg("debug: %s: divide by zero", __func__);
 279                         ret.uvalue = 123456789;
 280                 } else {
 281                         ret.uvalue = left.uvalue / right.uvalue;
 282                 }
 283                 break;
 284         case '+':
 285                 ret.uvalue = left.uvalue + right.uvalue;
 286                 break;
 287         case '-':
 288                 ret.uvalue = left.uvalue - right.uvalue;
 289                 break;
 290         case '%':
 291                 if (right.uvalue == 0) {
 292                         sm_msg("internal error: %s: MOD by zero", __func__);
 293                         ret.uvalue = 123456789;
 294                 } else {
 295                         ret.uvalue = left.uvalue % right.uvalue;
 296                 }
 297                 break;
 298         case '|':
 299                 ret.uvalue = left.uvalue | right.uvalue;
 300                 break;
 301         case '&':
 302                 ret.uvalue = left.uvalue & right.uvalue;
 303                 break;
 304         case SPECIAL_RIGHTSHIFT:
 305                 ret.uvalue = left.uvalue >> right.uvalue;
 306                 break;
 307         case SPECIAL_LEFTSHIFT:
 308                 ret.uvalue = left.uvalue << right.uvalue;
 309                 break;
 310         case '^':
 311                 ret.uvalue = left.uvalue ^ right.uvalue;
 312                 break;
 313         default:
 314                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 315                        show_special(op));
 316                 ret.uvalue = 1234567;
 317         }
 318         return ret;
 319 }
 320
 321
 322 static sval_t sval_binop_signed(struct symbol *type, sval_t left, int op, sval_t right)
 323 {
 324         sval_t ret;
 325
 326         ret.type = type;
 327         switch (op) {
 328         case '*':
 329                 ret.value =  left.value * right.value;
 330                 break;
 331         case '/':
 332                 if (right.value == 0) {
 333                         sm_msg("debug: %s: divide by zero", __func__);
 334                         ret.value = 123456789;
 335                 } else if (left.value == LLONG_MIN && right.value == -1) {
 336                         sm_msg("debug: %s: invalid divide LLONG_MIN/-1", __func__);
 337                         ret.value = 12345678;
 338                 } else {
 339                         ret.value = left.value / right.value;
 340                 }
 341                 break;
 342         case '+':
 343                 ret.value = left.value + right.value;
 344                 break;
 345         case '-':
 346                 ret.value = left.value - right.value;
 347                 break;
 348         case '%':
 349                 if (right.value == 0) {
 350                         sm_msg("internal error: %s: MOD by zero", __func__);
 351                         ret.value = 123456789;
 352                 } else {
 353                         ret.value = left.value % right.value;
 354                 }
 355                 break;
 356         case '|':
 357                 ret.value = left.value | right.value;
 358                 break;
 359         case '&':
 360                 ret.value = left.value & right.value;
 361                 break;
 362         case SPECIAL_RIGHTSHIFT:
 363                 ret.value = left.value >> right.value;
 364                 break;
 365         case SPECIAL_LEFTSHIFT:
 366                 ret.value = left.value << right.value;
 367                 break;
 368         case '^':
 369                 ret.value = left.value ^ right.value;
 370                 break;
 371         default:
 372                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 373                        show_special(op));
 374                 ret.value = 1234567;
 375         }
 376         return ret;
 377 }
 378
 379 sval_t sval_binop(sval_t left, int op, sval_t right)
 380 {
 381         struct symbol *type;
 382         sval_t ret;
 383
 384         type = left.type;
 385         if (sval_positive_bits(right) > sval_positive_bits(left))
 386                 type = right.type;
 387         if (type_positive_bits(type) < 31)
 388                 type = &int_ctype;
 389
 390         if (type_unsigned(type))
 391                 ret = sval_binop_unsigned(type, left, op, right);
 392         else
 393                 ret = sval_binop_signed(type, left, op, right);
 394         return ret;
 395 }
 396
 397 const char *sval_to_str(sval_t sval)
 398 {
 399         char buf[30];
 400
 401         if (sval_unsigned(sval) && sval.value == ULLONG_MAX)
 402                 return "u64max";
 403         if (sval.value == LLONG_MAX)
 404                 return "s64max";
 405         if (sval_unsigned(sval) && sval.value == UINT_MAX)
 406                 return "u32max";
 407         if (sval.value == INT_MAX)
 408                 return "s32max";
 409         if (sval_unsigned(sval) && sval.value == USHRT_MAX)
 410                 return "u16max";
 411
 412         if (sval_signed(sval) && sval.value == SHRT_MIN)
 413                 return "s16min";
 414         if (sval_signed(sval) && sval.value == INT_MIN)
 415                 return "s32min";
 416         if (sval_signed(sval) && sval.value == LLONG_MIN)
 417                 return "s64min";
 418
 419         if (sval_unsigned(sval))
 420                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 421         else if (sval.value < 0)
 422                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 423         else
 424                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 425
 426         return alloc_sname(buf);
 427 }
 428
 429 const char *sval_to_numstr(sval_t sval)
 430 {
 431         char buf[30];
 432
 433         if (sval_unsigned(sval))
 434                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 435         else if (sval.value < 0)
 436                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 437         else
 438                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 439
 440         return alloc_sname(buf);
 441 }
 442
 443 sval_t ll_to_sval(long long val)
 444 {
 445         sval_t ret;
 446
 447         ret.type = &llong_ctype;
 448         ret.value = val;
 449         return ret;
 450 }
 451
 452 static void free_svals(struct symbol *sym)
 453 {
 454         clear_sval_alloc();
 455 }
 456
 457 void register_sval(int my_id)
 458 {
 459         add_hook(&free_svals, END_FUNC_HOOK);
 460 }