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         struct symbol *type;
 168
 169         type = one.type;
 170         if (sval_positive_bits(two) > sval_positive_bits(one))
 171                 type = two.type;
 172         if (type_bits(type) < 31)
 173                 type = &int_ctype;
 174
 175         one = sval_cast(type, one);
 176         two = sval_cast(type, two);
 177
 178         if (type_unsigned(type)) {
 179                 if (one.uvalue < two.uvalue)
 180                         return -1;
 181                 if (one.uvalue == two.uvalue)
 182                         return 0;
 183                 return 1;
 184         }
 185         /* fix me handle type promotion and unsigned values */
 186         if (one.value < two.value)
 187                 return -1;
 188         if (one.value == two.value)
 189                 return 0;
 190         return 1;
 191 }
 192
 193 int sval_cmp_t(struct symbol *type, sval_t one, sval_t two)
 194 {
 195         sval_t one_cast, two_cast;
 196
 197         one_cast = sval_cast(type, one);
 198         two_cast = sval_cast(type, two);
 199         return sval_cmp(one_cast, two_cast);
 200 }
 201
 202 int sval_cmp_val(sval_t one, long long val)
 203 {
 204         if (one.value < val)
 205                 return -1;
 206         if (one.value == val)
 207                 return 0;
 208         return 1;
 209 }
 210
 211 sval_t sval_cast(struct symbol *type, sval_t sval)
 212 {
 213         sval_t ret;
 214
 215         if (!type)
 216                 type = &llong_ctype;
 217
 218         ret.type = type;
 219         switch (sval_bits(ret)) {
 220         case 8:
 221                 if (sval_unsigned(ret))
 222                         ret.value = (long long)(unsigned char)sval.value;
 223                 else
 224                         ret.value = (long long)(char)sval.value;
 225                 break;
 226         case 16:
 227                 if (sval_unsigned(ret))
 228                         ret.value = (long long)(unsigned short)sval.value;
 229                 else
 230                         ret.value = (long long)(short)sval.value;
 231                 break;
 232         case 32:
 233                 if (sval_unsigned(ret))
 234                         ret.value = (long long)(unsigned int)sval.value;
 235                 else
 236                         ret.value = (long long)(int)sval.value;
 237                 break;
 238         default:
 239                 ret.value = sval.value;
 240         }
 241         return ret;
 242
 243 }
 244
 245 sval_t sval_preop(sval_t sval, int op)
 246 {
 247         switch (op) {
 248         case '!':
 249                 sval.value = !sval.value;
 250                 break;
 251         case '~':
 252                 sval.value = ~sval.value;
 253                 /* fixme: should probably cast this here */
 254                 break;
 255         case '-':
 256                 sval.value = -sval.value;
 257                 break;
 258         }
 259         return sval;
 260 }
 261
 262 static sval_t sval_binop_unsigned(struct symbol *type, sval_t left, int op, sval_t right)
 263 {
 264         sval_t ret;
 265
 266         ret.type = type;
 267         switch (op) {
 268         case '*':
 269                 ret.uvalue =  left.uvalue * right.uvalue;
 270                 break;
 271         case '/':
 272                 if (right.uvalue == 0) {
 273                         sm_msg("debug: %s: divide by zero", __func__);
 274                         ret.uvalue = 123456789;
 275                 } else {
 276                         ret.uvalue = left.uvalue / right.uvalue;
 277                 }
 278                 break;
 279         case '+':
 280                 ret.uvalue = left.uvalue + right.uvalue;
 281                 break;
 282         case '-':
 283                 ret.uvalue = left.uvalue - right.uvalue;
 284                 break;
 285         case '%':
 286                 if (right.uvalue == 0) {
 287                         sm_msg("internal error: %s: MOD by zero", __func__);
 288                         ret.uvalue = 123456789;
 289                 } else {
 290                         ret.uvalue = left.uvalue % right.uvalue;
 291                 }
 292                 break;
 293         case '|':
 294                 ret.uvalue = left.uvalue | right.uvalue;
 295                 break;
 296         case '&':
 297                 ret.uvalue = left.uvalue & right.uvalue;
 298                 break;
 299         case SPECIAL_RIGHTSHIFT:
 300                 ret.uvalue = left.uvalue >> right.uvalue;
 301                 break;
 302         case SPECIAL_LEFTSHIFT:
 303                 ret.uvalue = left.uvalue << right.uvalue;
 304                 break;
 305         case '^':
 306                 ret.uvalue = left.uvalue ^ right.uvalue;
 307                 break;
 308         default:
 309                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 310                        show_special(op));
 311                 ret.uvalue = 1234567;
 312         }
 313         return ret;
 314 }
 315
 316
 317 static sval_t sval_binop_signed(struct symbol *type, sval_t left, int op, sval_t right)
 318 {
 319         sval_t ret;
 320
 321         ret.type = type;
 322         switch (op) {
 323         case '*':
 324                 ret.value =  left.value * right.value;
 325                 break;
 326         case '/':
 327                 if (right.value == 0) {
 328                         sm_msg("debug: %s: divide by zero", __func__);
 329                         ret.value = 123456789;
 330                 } else if (left.value == LLONG_MIN && right.value == -1) {
 331                         sm_msg("debug: %s: invalid divide LLONG_MIN/-1", __func__);
 332                         ret.value = 12345678;
 333                 } else {
 334                         ret.value = left.value / right.value;
 335                 }
 336                 break;
 337         case '+':
 338                 ret.value = left.value + right.value;
 339                 break;
 340         case '-':
 341                 ret.value = left.value - right.value;
 342                 break;
 343         case '%':
 344                 if (right.value == 0) {
 345                         sm_msg("internal error: %s: MOD by zero", __func__);
 346                         ret.value = 123456789;
 347                 } else {
 348                         ret.value = left.value % right.value;
 349                 }
 350                 break;
 351         case '|':
 352                 ret.value = left.value | right.value;
 353                 break;
 354         case '&':
 355                 ret.value = left.value & right.value;
 356                 break;
 357         case SPECIAL_RIGHTSHIFT:
 358                 ret.value = left.value >> right.value;
 359                 break;
 360         case SPECIAL_LEFTSHIFT:
 361                 ret.value = left.value << right.value;
 362                 break;
 363         case '^':
 364                 ret.value = left.value ^ right.value;
 365                 break;
 366         default:
 367                 sm_msg("internal error: %s: unhandled binop %s", __func__,
 368                        show_special(op));
 369                 ret.value = 1234567;
 370         }
 371         return ret;
 372 }
 373
 374 sval_t sval_binop(sval_t left, int op, sval_t right)
 375 {
 376         struct symbol *type;
 377         sval_t ret;
 378
 379         type = left.type;
 380         if (sval_positive_bits(right) > sval_positive_bits(left))
 381                 type = right.type;
 382         if (type_positive_bits(type) < 31)
 383                 type = &int_ctype;
 384
 385         if (type_unsigned(type))
 386                 ret = sval_binop_unsigned(type, left, op, right);
 387         else
 388                 ret = sval_binop_signed(type, left, op, right);
 389         return ret;
 390 }
 391
 392 const char *sval_to_str(sval_t sval)
 393 {
 394         char buf[30];
 395
 396         if (sval_unsigned(sval) && sval.value == ULLONG_MAX)
 397                 return "u64max";
 398         if (sval.value == LLONG_MAX)
 399                 return "s64max";
 400         if (sval_unsigned(sval) && sval.value == UINT_MAX)
 401                 return "u32max";
 402         if (sval.value == INT_MAX)
 403                 return "s32max";
 404         if (sval_unsigned(sval) && sval.value == USHRT_MAX)
 405                 return "u16max";
 406
 407         if (sval_signed(sval) && sval.value == SHRT_MIN)
 408                 return "s16min";
 409         if (sval_signed(sval) && sval.value == INT_MIN)
 410                 return "s32min";
 411         if (sval_signed(sval) && sval.value == LLONG_MIN)
 412                 return "s64min";
 413
 414         if (sval_unsigned(sval))
 415                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 416         else if (sval.value < 0)
 417                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 418         else
 419                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 420
 421         return alloc_sname(buf);
 422 }
 423
 424 const char *sval_to_numstr(sval_t sval)
 425 {
 426         char buf[30];
 427
 428         if (sval_unsigned(sval))
 429                 snprintf(buf, sizeof(buf), "%llu", sval.value);
 430         else if (sval.value < 0)
 431                 snprintf(buf, sizeof(buf), "(%lld)", sval.value);
 432         else
 433                 snprintf(buf, sizeof(buf), "%lld", sval.value);
 434
 435         return alloc_sname(buf);
 436 }
 437
 438 sval_t ll_to_sval(long long val)
 439 {
 440         sval_t ret;
 441
 442         ret.type = &llong_ctype;
 443         ret.value = val;
 444         return ret;
 445 }
 446
 447 static void free_svals(struct symbol *sym)
 448 {
 449         clear_sval_alloc();
 450 }
 451
 452 void register_sval(int my_id)
 453 {
 454         add_hook(&free_svals, END_FUNC_HOOK);
 455 }