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         if (!sval.type)
  88                 return 32;
  89         return sval.type->bit_size;
  90 }
  91
  92 int sval_positive_bits(sval_t sval)
  93 {
  94         if (!sval.type)
  95                 return 31;
  96         if (sval_signed(sval))
  97                 return sval.type->bit_size - 1;
  98         return sval.type->bit_size;
  99 }
 100
 101 int sval_bits_used(sval_t sval)
 102 {
 103         int i;
 104
 105         for (i = 64; i >= 1; i--) {
 106                 if (sval.uvalue & (1ULL << (i - 1)))
 107                         return i;
 108         }
 109         return 0;
 110 }
 111
 112 int sval_is_min(sval_t sval)
 113 {
 114         sval_t min = sval_type_min(sval.type);
 115
 116         if (sval_unsigned(sval)) {
 117                 if (sval.uvalue == 0)
 118                         return 1;
 119                 return 0;
 120         }
 121         /* return true for less than min as well */
 122         return (sval.value <= min.value);
 123 }
 124
 125 int sval_is_max(sval_t sval)
 126 {
 127         sval_t max = sval_type_max(sval.type);
 128
 129         if (sval_unsigned(sval))
 130                 return (sval.uvalue >= max.value);
 131         return (sval.value >= max.value);
 132 }
 133
 134 int sval_is_a_min(sval_t sval)
 135 {
 136         if (sval_signed(sval) && sval.value == SHRT_MIN)
 137                 return 1;
 138         if (sval_signed(sval) && sval.value == INT_MIN)
 139                 return 1;
 140         if (sval_signed(sval) && sval.value == LLONG_MIN)
 141                 return 1;
 142         return 0;
 143 }
 144
 145 int sval_is_a_max(sval_t sval)
 146 {
 147         if (sval.uvalue == SHRT_MAX)
 148                 return 1;
 149         if (sval.uvalue == INT_MAX)
 150                 return 1;
 151         if (sval.uvalue == LLONG_MAX)
 152                 return 1;
 153         if (sval.uvalue == USHRT_MAX)
 154                 return 1;
 155         if (sval.uvalue == UINT_MAX)
 156                 return 1;
 157         if (sval_unsigned(sval) && sval.uvalue == ULLONG_MAX)
 158                 return 1;
 159         return 0;
 160 }
 161
 162 /*
 163  * Returns -1 if one is smaller, 0 if they are the same and 1 if two is larger.
 164  */
 165 int sval_cmp(sval_t one, sval_t two)
 166 {
 167         sval_t tmp;
 168
 169         tmp = one;
 170         if (sval_positive_bits(two) > sval_positive_bits(one))
 171                 tmp = two;
 172         if (sval_bits(tmp) >= 32 && sval_unsigned(tmp)) {
 173                 if (one.uvalue < two.uvalue)
 174                         return -1;
 175                 if (one.uvalue == two.uvalue)
 176                         return 0;
 177                 return 1;
 178         }
 179         /* fix me handle type promotion and unsigned values */
 180         if (one.value < two.value)
 181                 return -1;
 182         if (one.value == two.value)
 183                 return 0;
 184         return 1;
 185 }
 186
 187 int sval_cmp_t(struct symbol *type, sval_t one, sval_t two)
 188 {
 189         sval_t one_cast, two_cast;
 190
 191         one_cast = sval_cast(type, one);
 192         two_cast = sval_cast(type, two);
 193         return sval_cmp(one_cast, two_cast);
 194 }
 195
 196 int sval_cmp_val(sval_t one, long long val)
 197 {
 198         if (one.value < val)
 199                 return -1;
 200         if (one.value == val)
 201                 return 0;
 202         return 1;
 203 }
 204
 205 sval_t sval_cast(struct symbol *type, sval_t sval)
 206 {
 207         sval_t ret;
 208
 209         if (!type)
 210                 type = &llong_ctype;
 211
 212         ret.type = type;
 213         switch (sval_bits(ret)) {
 214         case 8:
 215                 if (sval_unsigned(ret))
 216                         ret.value = (long long)(unsigned char)sval.value;
 217                 else
 218                         ret.value = (long long)(char)sval.value;
 219                 break;
 220         case 16:
 221                 if (sval_unsigned(ret))
 222                         ret.value = (long long)(unsigned short)sval.value;
 223                 else
 224                         ret.value = (long long)(short)sval.value;
 225                 break;
 226         case 32:
 227                 if (sval_unsigned(ret))
 228                         ret.value = (long long)(unsigned int)sval.value;
 229                 else
 230                         ret.value = (long long)(int)sval.value;
 231                 break;
 232         default:
 233                 ret.value = sval.value;
 234         }
 235         return ret;
 236
 237 }
 238
 239 sval_t sval_preop(sval_t sval, int op)
 240 {
 241         switch (op) {
 242         case '!':
 243                 sval.value = !sval.value;
 244                 break;
 245         case '~':
 246                 sval.value = ~sval.value;
 247                 /* fixme: should probably cast this here */
 248                 break;
 249         case '-':
 250                 sval.value = -sval.value;
 251                 break;
 252         }
 253         return sval;
 254 }
 255
 256 static sval_t sval_binop_unsigned(struct symbol *type, sval_t left, int op, sval_t right)
 257 {
 258         sval_t ret;
 259
 260         ret.type = type;
 261         switch (op) {
 262         case '*':
 263                 ret.uvalue =  left.uvalue * right.uvalue;
 264                 break;
 265         case '/':
 266                 if (right.uvalue == 0) {
 267                         sm_msg("debug: %s: divide by zero", __func__);
 268                         ret.uvalue = 123456789;
 269                 } else {
 270                         ret.uvalue = left.uvalue / right.uvalue;
 271                 }
 272                 break;
 273         case '+':
 274                 ret.uvalue = left.uvalue + right.uvalue;
 275                 break;
 276         case '-':
 277                 ret.uvalue = left.uvalue - right.uvalue;
 278                 break;
 279         case '%':
 280                 if (right.uvalue == 0) {
 281                         sm_msg("internal error: %s: MOD by zero", __func__);
 282                         ret.uvalue = 123456789;
 283                 } else {
 284                         ret.uvalue = left.uvalue % right.uvalue;
 285                 }
 286                 break;
 287         case '|':
 288                 ret.uvalue = left.uvalue | right.uvalue;
 289                 break;
 290         case '&':
 291                 ret.uvalue = left.uvalue & right.uvalue;
 292                 break;
 293         case SPECIAL_RIGHTSHIFT:
 294                 ret.uvalue = left.uvalue >> right.uvalue;
 295                 break;
 296         case SPECIAL_LEFTSHIFT:
 297                 ret.uvalue = left.uvalue << right.uvalue;
 298                 break;
 299         case '^':
 300                 ret.uvalue = left.uvalue ^ right.uvalue;
 301                 break;
 302         default:
 303                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 304                        show_special(op));
 305                 ret.uvalue = 1234567;
 306         }
 307         return ret;
 308 }
 309
 310
 311 static sval_t sval_binop_signed(struct symbol *type, sval_t left, int op, sval_t right)
 312 {
 313         sval_t ret;
 314
 315         ret.type = type;
 316         switch (op) {
 317         case '*':
 318                 ret.value =  left.value * right.value;
 319                 break;
 320         case '/':
 321                 if (right.value == 0) {
 322                         sm_msg("debug: %s: divide by zero", __func__);
 323                         ret.value = 123456789;
 324                 } else if (left.value == LLONG_MIN && right.value == -1) {
 325                         sm_msg("debug: %s: invalid divide LLONG_MIN/-1", __func__);
 326                         ret.value = 12345678;
 327                 } else {
 328                         ret.value = left.value / right.value;
 329                 }
 330                 break;
 331         case '+':
 332                 ret.value = left.value + right.value;
 333                 break;
 334         case '-':
 335                 ret.value = left.value - right.value;
 336                 break;
 337         case '%':
 338                 if (right.value == 0) {
 339                         sm_msg("internal error: %s: MOD by zero", __func__);
 340                         ret.value = 123456789;
 341                 } else {
 342                         ret.value = left.value % right.value;
 343                 }
 344                 break;
 345         case '|':
 346                 ret.value = left.value | right.value;
 347                 break;
 348         case '&':
 349                 ret.value = left.value & right.value;
 350                 break;
 351         case SPECIAL_RIGHTSHIFT:
 352                 ret.value = left.value >> right.value;
 353                 break;
 354         case SPECIAL_LEFTSHIFT:
 355                 ret.value = left.value << right.value;
 356                 break;
 357         case '^':
 358                 ret.value = left.value ^ right.value;
 359                 break;
 360         default:
 361                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 362                        show_special(op));
 363                 ret.value = 1234567;
 364         }
 365         return ret;
 366 }
 367
 368 sval_t sval_binop(sval_t left, int op, sval_t right)
 369 {
 370         struct symbol *type;
 371         sval_t ret;
 372
 373         type = left.type;
 374         if (sval_positive_bits(right) > sval_positive_bits(left))
 375                 type = right.type;
 376         if (type_positive_bits(type) < 31)
 377                 type = &int_ctype;
 378
 379         if (type_unsigned(type))
 380                 ret = sval_binop_unsigned(type, left, op, right);
 381         else
 382                 ret = sval_binop_signed(type, left, op, right);
 383         return ret;
 384 }
 385
 386 const char *sval_to_str(sval_t sval)
 387 {
 388         char buf[30];
 389
 390         if (sval_unsigned(sval) && sval.value == ULLONG_MAX)
 391                 return "u64max";
 392         if (sval.value == LLONG_MAX)
 393                 return "s64max";
 394         if (sval_unsigned(sval) && sval.value == UINT_MAX)
 395                 return "u32max";
 396         if (sval.value == INT_MAX)
 397                 return "s32max";
 398         if (sval_unsigned(sval) && sval.value == USHRT_MAX)
 399                 return "u16max";
 400
 401         if (sval_signed(sval) && sval.value == SHRT_MIN)
 402                 return "s16min";
 403         if (sval_signed(sval) && sval.value == INT_MIN)
 404                 return "s32min";
 405         if (sval_signed(sval) && sval.value == LLONG_MIN)
 406                 return "s64min";
 407
 408         if (sval_unsigned(sval))
 409                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 410         else if (sval.value < 0)
 411                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 412         else
 413                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 414
 415         return alloc_sname(buf);
 416 }
 417
 418 const char *sval_to_numstr(sval_t sval)
 419 {
 420         char buf[30];
 421
 422         if (sval_unsigned(sval))
 423                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 424         else if (sval.value < 0)
 425                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 426         else
 427                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 428
 429         return alloc_sname(buf);
 430 }
 431
 432 sval_t ll_to_sval(long long val)
 433 {
 434         sval_t ret;
 435
 436         ret.type = &llong_ctype;
 437         ret.value = val;
 438         return ret;
 439 }
 440
 441 static void free_svals(struct symbol *sym)
 442 {
 443         clear_sval_alloc();
 444 }
 445
 446 void register_sval(int my_id)
 447 {
 448         add_hook(&free_svals, END_FUNC_HOOK);
 449 }