mono/mini/abcremoval.c

   1 /*
   2  * abcremoval.c: Array bounds check removal
   3  *
   4  * Author:
   5  *   Massimiliano Mantione (massi@ximian.com)
   6  *
   7  * (C) 2004 Ximian, Inc.  http://www.ximian.com
   8  */
   9 #include <string.h>
  10 #include <stdio.h>
  11
  12 #include <mono/metadata/debug-helpers.h>
  13 #include <mono/metadata/mempool.h>
  14 #include <mono/metadata/opcodes.h>
  15 #include <mono/metadata/mempool-internals.h>
  16 #include <mono/utils/mono-compiler.h>
  17
  18 #include <config.h>
  19
  20 #ifndef DISABLE_JIT
  21
  22 #include "abcremoval.h"
  23
  24 #if SIZEOF_VOID_P == 8
  25 #define OP_PCONST OP_I8CONST
  26 #else
  27 #define OP_PCONST OP_ICONST
  28 #endif
  29
  30
  31 #define TRACE_ABC_REMOVAL (verbose_level > 2)
  32 #define REPORT_ABC_REMOVAL (verbose_level > 1)
  33
  34 /*
  35  * A little hack for the verbosity level.
  36  * The verbosity level is stored in the cfg, but not all functions that must
  37  * print something see the cfg, so we store the verbosity level here at the
  38  * beginning of the algorithm.
  39  * This is not thread safe (does not handle correctly different verbosity
  40  * levels in different threads), and is not exact in case of dynamic changes
  41  * of the verbosity level...
  42  * Anyway, this is not needed, all that can happen is that something more
  43  * (or less) is logged, the result is in any case correct.
  44  */
  45 static int verbose_level;
  46
  47
  48 #define RELATION_BETWEEN_VALUES(value,related_value) (\
  49         ((value) > (related_value))? MONO_GT_RELATION :\
  50         (((value) < (related_value))? MONO_LT_RELATION : MONO_EQ_RELATION))
  51
  52 #define MAKE_VALUE_ANY(v) do{\
  53                 (v).type = MONO_ANY_SUMMARIZED_VALUE;\
  54         } while (0)
  55
  56 #define MAKE_VALUE_RELATION_ANY(r) do{\
  57                 (r)->relation = MONO_ANY_RELATION;\
  58                 MAKE_VALUE_ANY((r)->related_value);\
  59         } while (0)
  60
  61 #define INITIALIZE_VALUE_RELATION(r) do{\
  62                 MAKE_VALUE_RELATION_ANY((r));\
  63                 (r)->next = NULL;\
  64         } while (0)
  65
  66 #define MONO_NEGATED_RELATION(r) ((MonoValueRelation)((~(r))&MONO_ANY_RELATION))
  67 #define MONO_SYMMETRIC_RELATION(r) ((MonoValueRelation)(((r)&MONO_EQ_RELATION)|(((r)&MONO_LT_RELATION)<<1)|((r&MONO_GT_RELATION)>>1)))
  68
  69
  70
  71 static void
  72 print_relation (int relation) {
  73         int print_or = 0;
  74         printf ("(");
  75         if (relation & MONO_LT_RELATION) {
  76                 printf ("LT");
  77                 print_or = 1;
  78         }
  79         if (relation & MONO_EQ_RELATION) {
  80                 if (print_or) {
  81                         printf ("|");
  82                 }
  83                 printf ("EQ");
  84                 print_or = 1;
  85         }
  86         if (relation & MONO_GT_RELATION) {
  87                 if (print_or) {
  88                         printf ("|");
  89                 }
  90                 printf ("GT");
  91                 print_or = 1;
  92         }
  93         printf (")");
  94 }
  95
  96 static void
  97 print_summarized_value (MonoSummarizedValue *value) {
  98         switch (value->type) {
  99         case MONO_ANY_SUMMARIZED_VALUE:
 100                 printf ("ANY");
 101                 break;
 102         case MONO_CONSTANT_SUMMARIZED_VALUE:
 103                 printf ("CONSTANT %d", value->value.constant.value);
 104                 break;
 105         case MONO_VARIABLE_SUMMARIZED_VALUE:
 106                 printf ("VARIABLE %d, delta %d", value->value.variable.variable, value->value.variable.delta);
 107                 break;
 108         case MONO_PHI_SUMMARIZED_VALUE: {
 109                 int phi;
 110                 printf ("PHI (");
 111                 for (phi = 0; phi < value->value.phi.number_of_alternatives; phi++) {
 112                         if (phi) printf (",");
 113                         printf ("%d", value->value.phi.phi_alternatives [phi]);
 114                 }
 115                 printf (")");
 116                 break;
 117         }
 118         default:
 119                 g_assert_not_reached ();
 120         }
 121 }
 122
 123 static void
 124 print_summarized_value_relation (MonoSummarizedValueRelation *relation) {
 125         printf ("Relation ");
 126         print_relation (relation->relation);
 127         printf (" with value ");
 128         print_summarized_value (&(relation->related_value));
 129 }
 130
 131 #if 0
 132 static void
 133 print_summarized_value_relation_chain (MonoSummarizedValueRelation *relation) {
 134         printf ("Relations:\n");
 135         while (relation) {
 136                 print_summarized_value_relation (relation);
 137                 printf ("\n");
 138                 relation = relation->next;
 139         }
 140 }
 141 #endif
 142
 143 static void
 144 print_evaluation_context_status (MonoRelationsEvaluationStatus status) {
 145         if (status == MONO_RELATIONS_EVALUATION_NOT_STARTED) {
 146                 printf ("EVALUATION_NOT_STARTED");
 147         } else {
 148                 gboolean print_or = FALSE;
 149
 150                 printf ("(");
 151                 if (status & MONO_RELATIONS_EVALUATION_IN_PROGRESS) {
 152                         if (print_or) printf ("|");
 153                         printf ("EVALUATION_IN_PROGRESS");
 154                         print_or = TRUE;
 155                 }
 156                 if (status & MONO_RELATIONS_EVALUATION_COMPLETED) {
 157                         if (print_or) printf ("|");
 158                         printf ("EVALUATION_COMPLETED");
 159                         print_or = TRUE;
 160                 }
 161                 if (status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_ASCENDING) {
 162                         if (print_or) printf ("|");
 163                         printf ("RECURSIVELY_ASCENDING");
 164                         print_or = TRUE;
 165                 }
 166                 if (status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_DESCENDING) {
 167                         if (print_or) printf ("|");
 168                         printf ("RECURSIVELY_DESCENDING");
 169                         print_or = TRUE;
 170                 }
 171                 if (status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_INDEFINITE) {
 172                         if (print_or) printf ("|");
 173                         printf ("RECURSIVELY_INDEFINITE");
 174                         print_or = TRUE;
 175                 }
 176                 printf (")");
 177         }
 178 }
 179
 180
 181 static void
 182 print_evaluation_context_ranges (MonoRelationsEvaluationRanges *ranges) {
 183         printf ("(ranges: zero [%d,%d], variable [%d,%d])", ranges->zero.lower, ranges->zero.upper, ranges->variable.lower, ranges->variable.upper);
 184 }
 185
 186 static void
 187 print_evaluation_context (MonoRelationsEvaluationContext *context, MonoRelationsEvaluationStatus status) {
 188         print_evaluation_context_status (status);
 189         if (status & (MONO_RELATIONS_EVALUATION_IN_PROGRESS|MONO_RELATIONS_EVALUATION_COMPLETED)) {
 190                 print_evaluation_context_ranges (&(context->ranges));
 191         }
 192         printf ("\n");
 193 }
 194
 195 #if 0
 196 static void
 197 print_evaluation_area (MonoVariableRelationsEvaluationArea *area) {
 198         int i;
 199         printf ("Dump of evaluation area (%d variables):\n", area->cfg->num_varinfo);
 200         for (i = 0; i < area->cfg->num_varinfo; i++) {
 201                 printf ("Variable %d: ", i);
 202                 print_evaluation_context (&(area->contexts [i]));
 203                 print_summarized_value_relation_chain (&(area->relations [i]));
 204         }
 205 }
 206
 207 static void
 208 print_evaluation_area_contexts (MonoVariableRelationsEvaluationArea *area) {
 209         int i;
 210         printf ("Dump of evaluation area contexts (%d variables):\n", area->cfg->num_varinfo);
 211         for (i = 0; i < area->cfg->num_varinfo; i++) {
 212                 printf ("Variable %d: ", i);
 213                 print_evaluation_context (&(area->contexts [i]));
 214         }
 215 }
 216 #endif
 217
 218 /*
 219  * Check if the delta of an integer variable value is safe with respect
 220  * to the variable size in bytes and its kind (signed or unsigned).
 221  * If the delta is not safe, make the value an "any".
 222  */
 223 static G_GNUC_UNUSED void
 224 check_delta_safety (MonoVariableRelationsEvaluationArea *area, MonoSummarizedValue *value) {
 225         if (value->type == MONO_VARIABLE_SUMMARIZED_VALUE) {
 226                 int variable = value->value.variable.variable;
 227                 int delta = value->value.variable.delta;
 228                 if ((area->variable_value_kind [variable]) & MONO_UNSIGNED_VALUE_FLAG) {
 229                         if (delta < 0) {
 230                                 MAKE_VALUE_ANY (*value);
 231                         }
 232                 } else {
 233                         if (((area->variable_value_kind [variable]) & MONO_INTEGER_VALUE_SIZE_BITMASK) < 4) {
 234                                 MAKE_VALUE_ANY (*value);
 235                         } else if (delta > 16) {
 236                                 MAKE_VALUE_ANY (*value);
 237                         }
 238                 }
 239         }
 240 }
 241
 242 /*
 243  * get_relation_from_ins:
 244  *
 245  *   Obtain relations from a MonoInst.
 246  *
 247  * result_value_kind: the "expected" kind of result;
 248  * result: the "summarized" value
 249  * returns the "actual" kind of result, if guessable (otherwise MONO_UNKNOWN_INTEGER_VALUE)
 250  */
 251 static MonoIntegerValueKind
 252 get_relation_from_ins (MonoVariableRelationsEvaluationArea *area, MonoInst *ins, MonoSummarizedValueRelation *result, MonoIntegerValueKind result_value_kind)
 253 {
 254         MonoIntegerValueKind value_kind;
 255         MonoSummarizedValue *value = &result->related_value;
 256
 257         if (ins->type == STACK_I8) {
 258                 value_kind = MONO_INTEGER_VALUE_SIZE_8;
 259         } else if (ins->type == STACK_I4) {
 260                 value_kind = MONO_INTEGER_VALUE_SIZE_4;
 261         } else {
 262                 value_kind = MONO_UNKNOWN_INTEGER_VALUE;
 263         }
 264
 265         result->relation = MONO_EQ_RELATION;
 266         MAKE_VALUE_ANY (*value);
 267
 268         switch (ins->opcode) {
 269         case OP_ICONST:
 270                 value->type = MONO_CONSTANT_SUMMARIZED_VALUE;
 271                 value->value.constant.value = ins->inst_c0;
 272                 break;
 273         case OP_MOVE:
 274                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 275                 value->value.variable.variable = ins->sreg1;
 276                 value->value.variable.delta = 0;
 277                 break;
 278         case OP_SEXT_I4:
 279                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 280                 value->value.variable.variable = ins->sreg1;
 281                 value->value.variable.delta = 0;
 282                 value_kind = MONO_INTEGER_VALUE_SIZE_8;
 283                 break;
 284         case OP_PHI:
 285                 value->type = MONO_PHI_SUMMARIZED_VALUE;
 286                 value->value.phi.number_of_alternatives = *(ins->inst_phi_args);
 287                 value->value.phi.phi_alternatives = ins->inst_phi_args + 1;
 288                 break;
 289         case OP_IADD_IMM:
 290                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 291                 value->value.variable.variable = ins->sreg1;
 292                 value->value.variable.delta = ins->inst_imm;
 293                 /* FIXME: */
 294                 //check_delta_safety (area, result);
 295                 break;
 296         case OP_ISUB_IMM:
 297                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 298                 value->value.variable.variable = ins->sreg1;
 299                 value->value.variable.delta = -ins->inst_imm;
 300                 /* FIXME: */
 301                 //check_delta_safety (area, result);
 302                 break;
 303         case OP_IREM_UN:
 304                 /* The result of an unsigned remainder is 0 < x < the divisor */
 305                 result->relation = MONO_LT_RELATION;
 306                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 307                 value->value.variable.variable = ins->sreg2;
 308                 value->value.variable.delta = 0;
 309                 value_kind = MONO_UNSIGNED_INTEGER_VALUE_SIZE_4;
 310                 break;
 311         case OP_LDLEN:
 312                 /*
 313                  * We represent arrays by their length, so r1<-ldlen r2 is stored
 314                  * as r1 == r2 in the evaluation graph.
 315                  */
 316                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 317                 value->value.variable.variable = ins->sreg1;
 318                 value->value.variable.delta = 0;
 319                 value_kind = MONO_UNSIGNED_INTEGER_VALUE_SIZE_4;
 320                 break;
 321         case OP_NEWARR:
 322                 value->type = MONO_VARIABLE_SUMMARIZED_VALUE;
 323                 value->value.variable.variable = ins->sreg1;
 324                 value->value.variable.delta = 0;
 325                 area->defs [ins->dreg] = ins;
 326                 break;
 327         case OP_LDADDR:
 328                 /* The result is non-null */
 329                 result->relation = MONO_GT_RELATION;
 330                 value->type = MONO_CONSTANT_SUMMARIZED_VALUE;
 331                 value->value.constant.value = 0;
 332                 break;
 333
 334                 /* FIXME: Add more opcodes */
 335         default:
 336                 /* These opcodes are not currently handled while running SciMark, first
 337                  * column is the number of times the warning was shown:
 338                  *
 339                  *       1 add_imm
 340                  *       1 float_conv_to_i8
 341                  *       1 int_mul_ovf_un
 342                  *       1 int_neg
 343                  *       1 int_or
 344                  *       1 int_shr_un
 345                  *       1 localloc
 346                  *       1 long_ceq
 347                  *       1 long_rem
 348                  *       1 long_sub
 349                  *       2 int_ceq
 350                  *       2 int_conv_to_i2
 351                  *       2 int_min
 352                  *       2 lcall
 353                  *       2 long_div
 354                  *       3 int_conv_to_u2
 355                  *       3 long_shr_imm
 356                  *       4 int_rem
 357                  *       4 int_rem_imm
 358                  *       4 loadi1_membase
 359                  *       4 loadu4_membase
 360                  *       5 int_div
 361                  *       5 shl_imm
 362                  *       6 int_div_imm
 363                  *       6 int_mul
 364                  *       9 int_mul_imm
 365                  *       9 zext_i4
 366                  *      10 int_shr_imm
 367                  *      12 int_shr_un_imm
 368                  *      12 long_add_imm
 369                  *      12 outarg_vtretaddr
 370                  *      12 strlen
 371                  *      13 int_or_imm
 372                  *      23 call_membase
 373                  *      23 int_conv_to_u1
 374                  *      23 long_add
 375                  *      24 int_and_imm
 376                  *      24 int_shl_imm
 377                  *      24 loadu2_membase
 378                  *      29 loadi8_membase
 379                  *      31 llvm_outarg_vt
 380                  *      34 int_sub
 381                  *      34 loadu1_membase
 382                  *      42 int_add
 383                  *      85 ldaddr
 384                  *     116 loadi4_membase
 385                  *     159 x86_lea
 386                  *     179 sext_i4
 387                  *     291 load_membase
 388                  *     462 i8const
 389                  *     472 call
 390                  */
 391
 392                 break;
 393         }
 394         return value_kind;
 395 }
 396
 397 static MonoValueRelation
 398 get_relation_from_branch_instruction (MonoInst *ins)
 399 {
 400         if (MONO_IS_COND_BRANCH_OP (ins)) {
 401                 CompRelation rel = mono_opcode_to_cond (ins->opcode);
 402
 403                 switch (rel) {
 404                 case CMP_EQ:
 405                         return MONO_EQ_RELATION;
 406                 case CMP_NE:
 407                         return MONO_NE_RELATION;
 408                 case CMP_LE:
 409                 case CMP_LE_UN:
 410                         return MONO_LE_RELATION;
 411                 case CMP_GE:
 412                 case CMP_GE_UN:
 413                         return MONO_GE_RELATION;
 414                 case CMP_LT:
 415                 case CMP_LT_UN:
 416                         return MONO_LT_RELATION;
 417                 case CMP_GT:
 418                 case CMP_GT_UN:
 419                         return MONO_GT_RELATION;
 420                 default:
 421                         g_assert_not_reached ();
 422                         return MONO_ANY_RELATION;
 423                 }
 424         } else {
 425                 return MONO_ANY_RELATION;
 426         }
 427 }
 428
 429 /*
 430  * Given a BB, find its entry condition and put its relations in a
 431  * "MonoAdditionalVariableRelationsForBB" structure.
 432  * bb: the BB
 433  * relations: the resulting relations (entry condition of the given BB)
 434  */
 435 static void
 436 get_relations_from_previous_bb (MonoVariableRelationsEvaluationArea *area, MonoBasicBlock *bb, MonoAdditionalVariableRelationsForBB *relations)
 437 {
 438         MonoBasicBlock *in_bb;
 439         MonoInst *ins, *compare, *branch;
 440         MonoValueRelation branch_relation;
 441         MonoValueRelation symmetric_relation;
 442         gboolean code_path;
 443
 444         INITIALIZE_VALUE_RELATION (&(relations->relation1.relation));
 445         relations->relation1.relation.relation_is_static_definition = FALSE;
 446         relations->relation1.relation.next = NULL;
 447         relations->relation1.insertion_point = NULL;
 448         relations->relation1.variable = -1;
 449         INITIALIZE_VALUE_RELATION (&(relations->relation2.relation));
 450         relations->relation2.relation.relation_is_static_definition = FALSE;
 451         relations->relation2.relation.next = NULL;
 452         relations->relation2.insertion_point = NULL;
 453         relations->relation2.variable = -1;
 454
 455         if (bb->in_count == 1) { /* Should write the code to "sum" conditions... */
 456                 in_bb = bb->in_bb [0];
 457
 458                 if ((in_bb->last_ins == NULL) || (in_bb->code == in_bb->last_ins))
 459                         return;
 460
 461                 for (ins = in_bb->code; ins->next != in_bb->last_ins; ins = ins->next)
 462                         ;
 463
 464                 compare = ins;
 465                 branch = ins->next;
 466                 branch_relation = get_relation_from_branch_instruction (branch);
 467
 468                 if (branch_relation != MONO_ANY_RELATION) {
 469                         if (branch->inst_true_bb == bb) {
 470                                 code_path = TRUE;
 471                         } else if (branch->inst_false_bb == bb) {
 472                                 code_path = FALSE;
 473                         } else {
 474                                 code_path = TRUE;
 475                                 g_assert_not_reached ();
 476                         }
 477                         if (!code_path)
 478                                 branch_relation = MONO_NEGATED_RELATION (branch_relation);
 479                         symmetric_relation = MONO_SYMMETRIC_RELATION (branch_relation);
 480
 481                         /* FIXME: Other compare opcodes */
 482                         if (compare->opcode == OP_ICOMPARE) {
 483                                 relations->relation1.variable = compare->sreg1;
 484                                 relations->relation1.relation.relation = branch_relation;
 485                                 relations->relation1.relation.related_value.type = MONO_VARIABLE_SUMMARIZED_VALUE;
 486                                 relations->relation1.relation.related_value.value.variable.variable = compare->sreg2;
 487                                 relations->relation1.relation.related_value.value.variable.delta = 0;
 488
 489                                 relations->relation2.variable = compare->sreg2;
 490                                 relations->relation2.relation.relation = symmetric_relation;
 491                                 relations->relation2.relation.related_value.type = MONO_VARIABLE_SUMMARIZED_VALUE;
 492                                 relations->relation2.relation.related_value.value.variable.variable = compare->sreg1;
 493                                 relations->relation2.relation.related_value.value.variable.delta = 0;
 494                         } else if (compare->opcode == OP_ICOMPARE_IMM) {
 495                                 relations->relation1.variable = compare->sreg1;
 496                                 relations->relation1.relation.relation = branch_relation;
 497                                 relations->relation1.relation.related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
 498                                 relations->relation1.relation.related_value.value.constant.value = compare->inst_imm;
 499                         }
 500                 }
 501         }
 502 }
 503
 504 /*
 505  * Add the given relations to the evaluation area.
 506  * area: the evaluation area
 507  * change: the relations that must be added
 508  */
 509 static void
 510 apply_change_to_evaluation_area (MonoVariableRelationsEvaluationArea *area, MonoAdditionalVariableRelation *change)
 511 {
 512         MonoSummarizedValueRelation *base_relation;
 513
 514         if (change->relation.relation != MONO_ANY_RELATION) {
 515                 base_relation = &(area->relations [change->variable]);
 516                 while ((base_relation->next != NULL) && (base_relation->next->relation_is_static_definition)) {
 517                         base_relation = base_relation->next;
 518                 }
 519                 change->insertion_point = base_relation;
 520                 change->relation.next = base_relation->next;
 521                 base_relation->next = &(change->relation);
 522         }
 523 }
 524
 525 /*
 526  * Remove the given relation from the evaluation area.
 527  * change: the relation that must be removed
 528  */
 529 static void
 530 remove_change_from_evaluation_area (MonoAdditionalVariableRelation *change)
 531 {
 532         if (change->insertion_point != NULL) {
 533                 change->insertion_point->next = change->relation.next;
 534                 change->relation.next = NULL;
 535         }
 536 }
 537
 538
 539 static void
 540 clean_contexts (MonoVariableRelationsEvaluationArea *area, int number)
 541 {
 542         memset(area->statuses, MONO_RELATIONS_EVALUATION_NOT_STARTED, number * sizeof(MonoRelationsEvaluationStatus));
 543 }
 544
 545
 546 /*
 547  * Perform the intersection of a range and a constant value (taking into
 548  * account the relation that the value has with the range).
 549  * range: the range that will be intersected with the value
 550  * value: the value that will be intersected with the range
 551  * relation: the relation between the range and the value
 552  */
 553 static void
 554 intersect_value( MonoRelationsEvaluationRange *range, int value, MonoValueRelation relation )
 555 {
 556         switch (relation) {
 557         case MONO_NO_RELATION:
 558                 MONO_MAKE_RELATIONS_EVALUATION_RANGE_IMPOSSIBLE (*range);
 559                 break;
 560         case MONO_ANY_RELATION:
 561                 break;
 562         case MONO_EQ_RELATION:
 563                 MONO_UPPER_EVALUATION_RANGE_INTERSECTION (range->upper, value);
 564                 MONO_LOWER_EVALUATION_RANGE_INTERSECTION (range->lower, value);
 565                 break;
 566         case MONO_NE_RELATION: {
 567                 /* IMPROVEMENT Figure this out! (ignoring it is safe anyway) */
 568                 break;
 569         }
 570         case MONO_LT_RELATION:
 571                 MONO_UPPER_EVALUATION_RANGE_INTERSECTION (range->upper, MONO_UPPER_EVALUATION_RANGE_NOT_EQUAL (value));
 572                 break;
 573         case MONO_LE_RELATION:
 574                 MONO_UPPER_EVALUATION_RANGE_INTERSECTION (range->upper, value);
 575                 break;
 576         case MONO_GT_RELATION:
 577                 MONO_LOWER_EVALUATION_RANGE_INTERSECTION (range->lower, MONO_LOWER_EVALUATION_RANGE_NOT_EQUAL (value));
 578                 break;
 579         case MONO_GE_RELATION:
 580                 MONO_LOWER_EVALUATION_RANGE_INTERSECTION (range->lower, value);
 581                 break;
 582         default:
 583                 g_assert_not_reached();
 584         }
 585 }
 586
 587
 588 /*
 589  * Perform the intersection of two pairs of ranges (taking into account the
 590  * relation between the ranges and a given delta).
 591  * ranges: the ranges that will be intersected
 592  * other_ranges the other ranges that will be intersected
 593  * delta: the delta between the pairs of ranges
 594  * relation: the relation between the pairs of ranges
 595  */
 596 static void
 597 intersect_ranges( MonoRelationsEvaluationRanges *ranges, MonoRelationsEvaluationRanges *other_ranges, int delta, MonoValueRelation relation )
 598 {
 599         if (delta == 0) {
 600                 switch (relation) {
 601                 case MONO_NO_RELATION:
 602                         MONO_MAKE_RELATIONS_EVALUATION_RANGES_IMPOSSIBLE (*ranges);
 603                         break;
 604                 case MONO_ANY_RELATION:
 605                         break;
 606                 case MONO_EQ_RELATION:
 607                         MONO_RELATIONS_EVALUATION_RANGES_INTERSECTION (*ranges, *other_ranges);
 608                         break;
 609                 case MONO_NE_RELATION: {
 610                         /* FIXME Figure this out! (ignoring it is safe anyway) */
 611                         break;
 612                 }
 613                 case MONO_LT_RELATION:
 614                         MONO_UPPER_EVALUATION_RANGE_INTERSECTION (ranges->zero.upper, MONO_UPPER_EVALUATION_RANGE_NOT_EQUAL (other_ranges->zero.upper));
 615                         MONO_UPPER_EVALUATION_RANGE_INTERSECTION (ranges->variable.upper, MONO_UPPER_EVALUATION_RANGE_NOT_EQUAL (other_ranges->variable.upper));
 616                         break;
 617                 case MONO_LE_RELATION:
 618                         MONO_UPPER_EVALUATION_RANGE_INTERSECTION (ranges->zero.upper, other_ranges->zero.upper);
 619                         MONO_UPPER_EVALUATION_RANGE_INTERSECTION (ranges->variable.upper, other_ranges->variable.upper);
 620                         break;
 621                 case MONO_GT_RELATION:
 622                         MONO_LOWER_EVALUATION_RANGE_INTERSECTION (ranges->zero.lower, MONO_LOWER_EVALUATION_RANGE_NOT_EQUAL (other_ranges->zero.lower));
 623                         MONO_LOWER_EVALUATION_RANGE_INTERSECTION (ranges->variable.lower, MONO_LOWER_EVALUATION_RANGE_NOT_EQUAL (other_ranges->variable.lower));
 624                         break;
 625                 case MONO_GE_RELATION:
 626                         MONO_LOWER_EVALUATION_RANGE_INTERSECTION (ranges->zero.lower, other_ranges->zero.lower);
 627                         MONO_LOWER_EVALUATION_RANGE_INTERSECTION (ranges->variable.lower, other_ranges->variable.lower);
 628                         break;
 629                 default:
 630                         g_assert_not_reached();
 631                 }
 632         } else {
 633                 MonoRelationsEvaluationRanges translated_ranges = *other_ranges;
 634                 MONO_ADD_DELTA_SAFELY_TO_RANGES (translated_ranges, delta);
 635                 intersect_ranges( ranges, &translated_ranges, FALSE, relation );
 636         }
 637 }
 638
 639 /*
 640  * Recursive method that traverses the relation graph to evaluate the
 641  * relation between two variables.
 642  * At the end of the execution, the resulting ranges are in the context of
 643  * the "starting" variable.
 644  * area: the current evaluation area (it contains the relation graph and
 645  *       memory for all the evaluation contexts is already allocated)
 646  * variable: starting variable (the value ranges in its context are the result
 647  *           of the execution of this procedure)
 648  * target_variable: the variable with respect to which the starting variable
 649  *                  is evaluated (tipically the starting variable is the index
 650  *                  and the target one is the array (which means its length))
 651  * father_context: the previous evaluation context in recursive invocations
 652  *                 (or NULL for the first invocation)
 653  */
 654 static void
 655 evaluate_relation_with_target_variable (MonoVariableRelationsEvaluationArea *area, const int variable, const int target_variable, MonoRelationsEvaluationContext *father_context)
 656 {
 657         MonoRelationsEvaluationContext * const context = &(area->contexts [variable]);
 658         MonoRelationsEvaluationStatus * const status = &(area->statuses [variable]);
 659
 660         // First of all, we check the evaluation status
 661         // (what must be done is *very* different in each case)
 662         switch (*status) {
 663         case MONO_RELATIONS_EVALUATION_NOT_STARTED: {
 664                 MonoSummarizedValueRelation *relation = &(area->relations [variable]);
 665
 666                 if (TRACE_ABC_REMOVAL) {
 667                         printf ("Evaluating variable %d (target variable %d)\n", variable, target_variable);
 668                         print_summarized_value_relation (relation);
 669                         printf ("\n");
 670                 }
 671
 672                 // We properly inizialize the context
 673                 *status = MONO_RELATIONS_EVALUATION_IN_PROGRESS;
 674                 context->father = father_context;
 675                 MONO_MAKE_RELATIONS_EVALUATION_RANGES_WEAK (context->ranges);
 676
 677                 // If we have found the target variable, we can set the range
 678                 // related to it in the context to "equal" (which is [0,0])
 679                 if (variable == target_variable) {
 680                         if (TRACE_ABC_REMOVAL) {
 681                                 printf ("Target variable reached (%d), continuing to evaluate relations with constants\n", variable);
 682                         }
 683                         context->ranges.variable.lower = 0;
 684                         context->ranges.variable.upper = 0;
 685                 }
 686
 687                 // Examine all relations for this variable (scan the list)
 688                 // The contribute of each relation will be intersected (logical and)
 689                 while (relation != NULL) {
 690                         context->current_relation = relation;
 691
 692                         if (TRACE_ABC_REMOVAL) {
 693                                 printf ("Processing (%d): ", variable);
 694                                 print_summarized_value_relation (relation);
 695                                 printf ("\n");
 696                         }
 697
 698                         // We decie what to do according the the type of the related value
 699                         switch (relation->related_value.type) {
 700                         case MONO_ANY_SUMMARIZED_VALUE:
 701                                 // No added information, skip it
 702                                 break;
 703                         case MONO_CONSTANT_SUMMARIZED_VALUE:
 704                                 // Intersect range with constant (taking into account the relation)
 705                                 intersect_value (&(context->ranges.zero), relation->related_value.value.constant.value, relation->relation);
 706                                 break;
 707                         case MONO_VARIABLE_SUMMARIZED_VALUE:
 708                                 // Generally, evaluate related variable and intersect ranges.
 709                                 // However, some check is necessary...
 710
 711                                 // If the relation is "ANY", nothing to do (no added information)
 712                                 if (relation->relation != MONO_ANY_RELATION) {
 713                                         int related_variable = relation->related_value.value.variable.variable;
 714                                         MonoRelationsEvaluationContext *related_context = &(area->contexts [related_variable]);
 715                                         MonoRelationsEvaluationStatus related_status = area->statuses [related_variable];
 716
 717                                         // The second condition in the "or" avoids messing with "back edges" in the graph traversal
 718                                         // (they are simply ignored instead of triggering the handling of recursion)
 719                                         if ( (related_status == MONO_RELATIONS_EVALUATION_NOT_STARTED) || !
 720                                                         ((related_context->current_relation->related_value.type == MONO_VARIABLE_SUMMARIZED_VALUE) &&
 721                                                         (related_context->current_relation->related_value.value.variable.variable == variable))) {
 722                                                 // Evaluate the related variable
 723                                                 evaluate_relation_with_target_variable (area, related_variable, target_variable, context);
 724
 725                                                 // Check if we are part of a recursive loop
 726                                                 if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVE) {
 727                                                         if (TRACE_ABC_REMOVAL) {
 728                                                                 printf ("Recursivity detected for variable %d (target variable %d), status ", variable, target_variable);
 729                                                                 print_evaluation_context_status (*status);
 730                                                         }
 731
 732                                                         // If we are, check if the evaluation of the related variable is complete
 733                                                         if (related_status == MONO_RELATIONS_EVALUATION_COMPLETED) {
 734                                                                 // If it is complete, we are part of a recursive definition.
 735                                                                 // Since it is a *definition* (and definitions are evaluated *before*
 736                                                                 // conditions because they are first in the list), intersection is not
 737                                                                 // strictly necessary, we simply copy the ranges and apply the delta
 738                                                                 context->ranges = related_context->ranges;
 739                                                                 /* Delta has already been checked for over/under-flow when evaluating values */
 740                                                                 MONO_ADD_DELTA_SAFELY_TO_RANGES (context->ranges, relation->related_value.value.variable.delta);
 741                                                                 *status = MONO_RELATIONS_EVALUATION_COMPLETED;
 742                                                                 if (TRACE_ABC_REMOVAL) {
 743                                                                         printf (", ranges already computed, result: \n");
 744                                                                         print_evaluation_context_ranges (&(context->ranges));
 745                                                                         printf (" (delta is %d)\n", relation->related_value.value.variable.delta);
 746                                                                 }
 747                                                         } else {
 748                                                                 // If it is not complete, do nothing (we do not have enough information)
 749                                                                 if (TRACE_ABC_REMOVAL) {
 750                                                                         printf (", ranges not computed\n");
 751                                                                 }
 752                                                         }
 753                                                 } else {
 754                                                         // If we are not (the common case) intersect the result
 755                                                         intersect_ranges( &(context->ranges), &(related_context->ranges), relation->related_value.value.variable.delta, relation->relation );
 756                                                 }
 757                                         } else {
 758                                                 if (TRACE_ABC_REMOVAL) {
 759                                                         printf ("Relation is a back-edge in this traversal, skipping\n");
 760                                                 }
 761                                         }
 762                                 }
 763                                 break;
 764                         case MONO_PHI_SUMMARIZED_VALUE: {
 765                                 // We must compute all PHI alternatives, combining the results (with a union, which is a logical "or"),
 766                                 // and intersect this result with the ranges in the context; we must also take into account recursions
 767                                 // (with loops that can be ascending, descending, or indefinite)
 768                                 MonoRelationsEvaluationRanges phi_ranges;
 769                                 int phi;
 770                                 gboolean is_ascending = FALSE;
 771                                 gboolean is_descending = FALSE;
 772
 773                                 MONO_MAKE_RELATIONS_EVALUATION_RANGES_IMPOSSIBLE (phi_ranges);
 774                                 for (phi = 0; phi < relation->related_value.value.phi.number_of_alternatives; phi++) {
 775                                         int phi_alternative = relation->related_value.value.phi.phi_alternatives [phi];
 776                                         evaluate_relation_with_target_variable (area, phi_alternative, target_variable, context);
 777
 778                                         // This means we are part of a recursive loop
 779                                         if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVE) {
 780                                                 if (TRACE_ABC_REMOVAL) {
 781                                                         printf ("Recursivity detected for variable %d (target variable %d), status ", variable, target_variable);
 782                                                         print_evaluation_context_status (*status);
 783                                                         printf ("\n");
 784                                                 }
 785                                                 if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_ASCENDING) {
 786                                                         is_ascending = TRUE;
 787                                                 }
 788                                                 if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_DESCENDING) {
 789                                                         is_descending = TRUE;
 790                                                 }
 791                                                 if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_INDEFINITE) {
 792                                                         is_ascending = TRUE;
 793                                                         is_descending = TRUE;
 794                                                 }
 795
 796                                                 // Clear "recursivity" bits in the status (recursion has been handled)
 797                                                 *status = MONO_RELATIONS_EVALUATION_IN_PROGRESS;
 798                                         } else {
 799                                                 MONO_RELATIONS_EVALUATION_RANGES_UNION (phi_ranges, area->contexts [phi_alternative].ranges);
 800                                         }
 801                                 }
 802
 803                                 // Apply the effects of all recursive loops
 804                                 if (is_ascending) {
 805                                         phi_ranges.zero.upper = INT_MAX;
 806                                         phi_ranges.variable.upper = INT_MAX;
 807                                 }
 808                                 if (is_descending) {
 809                                         phi_ranges.zero.lower = INT_MIN;
 810                                         phi_ranges.variable.lower = INT_MIN;
 811                                 }
 812
 813                                 // Intersect final result
 814                                 MONO_RELATIONS_EVALUATION_RANGES_INTERSECTION (context->ranges, phi_ranges);
 815                                 break;
 816                         }
 817                         default:
 818                                 g_assert_not_reached();
 819                         }
 820
 821                         // Pass to next relation
 822                         relation = relation->next;
 823                 }
 824
 825                 // Check if any recursivity bits are still in the status, and in any case clear them
 826                 if (*status & MONO_RELATIONS_EVALUATION_IS_RECURSIVE) {
 827                         if (TRACE_ABC_REMOVAL) {
 828                                 printf ("Recursivity for variable %d (target variable %d) discards computation, status ", variable, target_variable);
 829                                 print_evaluation_context_status (*status);
 830                                 printf ("\n");
 831                         }
 832                         // If yes, we did not have enough information (most likely we were evaluated inside a PHI, but we also
 833                         // depended on the same PHI, which was still in evaluation...), so clear the status to "NOT_STARTED"
 834                         // (if we will be evaluated again, the PHI will be already done, so our evaluation will succeed)
 835                         *status = MONO_RELATIONS_EVALUATION_NOT_STARTED;
 836                 } else {
 837                         if (TRACE_ABC_REMOVAL) {
 838                                 printf ("Ranges for variable %d (target variable %d) computed: ", variable, target_variable);
 839                                 print_evaluation_context_ranges (&(context->ranges));
 840                                 printf ("\n");
 841                         }
 842                         // If not (the common case) the evaluation is complete, and the result is in the context
 843                         *status = MONO_RELATIONS_EVALUATION_COMPLETED;
 844                 }
 845                 break;
 846         }
 847         case MONO_RELATIONS_EVALUATION_IN_PROGRESS: {
 848                 // This means we are in a recursive loop
 849                 MonoRelationsEvaluationContext *current_context = father_context;
 850                 MonoRelationsEvaluationContext *last_context = context->father;
 851                 gboolean evaluation_can_be_recursive = TRUE;
 852                 gboolean evaluation_is_definition = TRUE;
 853                 int path_value = 0;
 854
 855                 if (TRACE_ABC_REMOVAL) {
 856                         printf ("Evaluation of variable %d (target variable %d) already in progress\n", variable, target_variable);
 857                         print_evaluation_context (context, *status);
 858                         print_summarized_value_relation (context->current_relation);
 859                         printf ("\n");
 860                 }
 861
 862                 // We must check if the loop can be a recursive definition (we scan the whole loop)
 863                 while (current_context != last_context) {
 864                         if (current_context == NULL) {
 865                                 printf ("Broken recursive ring in ABC removal\n");
 866                                 g_assert_not_reached ();
 867                         }
 868
 869                         if (current_context->current_relation->relation_is_static_definition) {
 870                                 if (current_context->current_relation->related_value.type == MONO_VARIABLE_SUMMARIZED_VALUE) {
 871                                         /* No need to check path_value for over/under-flow, since delta should be safe */
 872                                         path_value += current_context->current_relation->related_value.value.variable.delta;
 873                                 } else if (current_context->current_relation->related_value.type != MONO_PHI_SUMMARIZED_VALUE) {
 874                                         evaluation_can_be_recursive = FALSE;
 875                                 }
 876                         } else {
 877                                 evaluation_is_definition = FALSE;
 878                                 evaluation_can_be_recursive = FALSE;
 879                         }
 880
 881                         current_context = current_context->father;
 882                 }
 883
 884                 // If this is a recursive definition, we properly flag the status in all the involved contexts
 885                 if (evaluation_is_definition) {
 886                         MonoRelationsEvaluationStatus recursive_status;
 887                         if (evaluation_can_be_recursive) {
 888                                 if (path_value > 0) {
 889                                         recursive_status = MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_ASCENDING;
 890                                 } else if (path_value < 0) {
 891                                         recursive_status = MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_DESCENDING;
 892                                 } else {
 893                                         recursive_status = MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_INDEFINITE;
 894                                 }
 895                         } else {
 896                                 recursive_status = MONO_RELATIONS_EVALUATION_IS_RECURSIVELY_INDEFINITE;
 897                         }
 898
 899                         if (TRACE_ABC_REMOVAL) {
 900                                 printf ("Recursivity accepted (");
 901                                 print_evaluation_context_status (recursive_status);
 902                                 printf (")\n");
 903                         }
 904
 905                         current_context = father_context;
 906                         while (current_context != last_context) {
 907                                 int index = father_context - area->contexts;
 908                                 MonoRelationsEvaluationStatus *current_status = &(area->statuses [index]);
 909                                 *current_status = (MonoRelationsEvaluationStatus)(*current_status | recursive_status);
 910                                 current_context = current_context->father;
 911                         }
 912                 } else {
 913                         if (TRACE_ABC_REMOVAL) {
 914                                 printf ("Recursivity rejected (some relation in the cycle is not a defintion)\n");
 915                         }
 916                 }
 917                 break;
 918         }
 919         case MONO_RELATIONS_EVALUATION_COMPLETED: {
 920                 return;
 921         }
 922         default:
 923                 if (TRACE_ABC_REMOVAL) {
 924                         printf ("Variable %d (target variable %d) already in a recursive ring, skipping\n", variable, target_variable);
 925                         print_evaluation_context (context, *status);
 926                         print_summarized_value_relation (context->current_relation);
 927                         printf ("\n");
 928                 }
 929                 break;
 930         }
 931
 932 }
 933
 934 /*
 935  * Apply the given value kind to the given range
 936  */
 937 static void
 938 apply_value_kind_to_range (MonoRelationsEvaluationRange *range, MonoIntegerValueKind value_kind)
 939 {
 940         if (value_kind != MONO_UNKNOWN_INTEGER_VALUE) {
 941                 if (value_kind & MONO_UNSIGNED_VALUE_FLAG) {
 942                         if (range->lower < 0) {
 943                                 range->lower = 0;
 944                         }
 945                         if ((value_kind & MONO_INTEGER_VALUE_SIZE_BITMASK) == 1) {
 946                                 if (range->upper > 0xff) {
 947                                         range->upper = 0xff;
 948                                 }
 949                         } else if ((value_kind & MONO_INTEGER_VALUE_SIZE_BITMASK) == 2) {
 950                                 if (range->upper > 0xffff) {
 951                                         range->upper = 0xffff;
 952                                 }
 953                         }
 954                 } else {
 955                         if ((value_kind & MONO_INTEGER_VALUE_SIZE_BITMASK) == 1) {
 956                                 if (range->lower < -0x80) {
 957                                         range->lower = -0x80;
 958                                 }
 959                                 if (range->upper > 0x7f) {
 960                                         range->upper = 0x7f;
 961                                 }
 962                         } else if ((value_kind & MONO_INTEGER_VALUE_SIZE_BITMASK) == 2) {
 963                                 if (range->lower < -0x8000) {
 964                                         range->lower = -0x8000;
 965                                 }
 966                                 if (range->upper > 0x7fff) {
 967                                         range->upper = 0x7fff;
 968                                 }
 969                         }
 970                 }
 971         }
 972 }
 973
 974 /*
 975  * Attempt the removal of bounds checks from a MonoInst.
 976  * inst: the MonoInst
 977  * area: the current evaluation area (it contains the relation graph and
 978  *       memory for all the evaluation contexts is already allocated)
 979  */
 980 static void
 981 remove_abc_from_inst (MonoInst *ins, MonoVariableRelationsEvaluationArea *area)
 982 {
 983         /* FIXME: Add support for 'constant' arrays and constant indexes */
 984
 985         int array_variable = ins->sreg1;
 986         int index_variable = ins->sreg2;
 987         MonoRelationsEvaluationContext *array_context = &(area->contexts [array_variable]);
 988         MonoRelationsEvaluationContext *index_context = &(area->contexts [index_variable]);
 989
 990         clean_contexts (area, area->cfg->next_vreg);
 991
 992         evaluate_relation_with_target_variable (area, index_variable, array_variable, NULL);
 993         evaluate_relation_with_target_variable (area, array_variable, array_variable, NULL);
 994
 995         if ((index_context->ranges.zero.lower >=0) && ((index_context->ranges.variable.upper < 0)||(index_context->ranges.zero.upper < array_context->ranges.zero.lower))) {
 996                 if (REPORT_ABC_REMOVAL) {
 997                         printf ("ARRAY-ACCESS: removed bounds check on array %d with index %d\n",
 998                                         array_variable, index_variable);
 999                 }
1000                 NULLIFY_INS (ins);
1001         } else {
1002                 if (TRACE_ABC_REMOVAL) {
1003                         if (index_context->ranges.zero.lower >= 0) {
1004                                 printf ("ARRAY-ACCESS: Removed lower bound check on array %d with index %d\n", array_variable, index_variable);
1005                         }
1006                         if (index_context->ranges.variable.upper < 0) {
1007                                 printf ("ARRAY-ACCESS: Removed upper bound check (through variable) on array %d with index %d\n", array_variable, index_variable);
1008                         }
1009                         if (index_context->ranges.zero.upper < array_context->ranges.zero.lower) {
1010                                 printf ("ARRAY-ACCESS: Removed upper bound check (through constant) on array %d with index %d\n", array_variable, index_variable);
1011                         }
1012                 }
1013         }
1014 }
1015
1016 static gboolean
1017 eval_non_null (MonoVariableRelationsEvaluationArea *area, int reg)
1018 {
1019         MonoRelationsEvaluationContext *context = &(area->contexts [reg]);
1020
1021         clean_contexts (area, area->cfg->next_vreg);
1022         evaluate_relation_with_target_variable (area, reg, reg, NULL);
1023
1024         return context->ranges.zero.lower > 0;
1025 }
1026
1027 static void
1028 add_non_null (MonoVariableRelationsEvaluationArea *area, MonoCompile *cfg, int reg,
1029                           GSList **check_relations)
1030 {
1031         MonoAdditionalVariableRelation *rel;
1032
1033         rel = (MonoAdditionalVariableRelation *)mono_mempool_alloc0 (cfg->mempool, sizeof (MonoAdditionalVariableRelation));
1034         rel->variable = reg;
1035         rel->relation.relation = MONO_GT_RELATION;
1036         rel->relation.related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
1037         rel->relation.related_value.value.constant.value = 0;
1038
1039         apply_change_to_evaluation_area (area, rel);
1040
1041         *check_relations = g_slist_append_mempool (cfg->mempool, *check_relations, rel);
1042 }
1043
1044 /*
1045  * Process a BB removing bounds checks from array accesses.
1046  * It does the following (in sequence):
1047  * - Get the BB entry condition
1048  * - Add its relations to the relation graph in the evaluation area
1049  * - Process all the MonoInst trees in the BB
1050  * - Recursively process all the children BBs in the dominator tree
1051  * - Remove the relations previously added to the relation graph
1052  *
1053  * bb: the BB that must be processed
1054  * area: the current evaluation area (it contains the relation graph and
1055  *       memory for all the evaluation contexts is already allocated)
1056  */
1057 static void
1058 process_block (MonoCompile *cfg, MonoBasicBlock *bb, MonoVariableRelationsEvaluationArea *area) {
1059         int inst_index;
1060         MonoInst *ins;
1061         MonoAdditionalVariableRelationsForBB additional_relations;
1062         GSList *dominated_bb, *l;
1063         GSList *check_relations = NULL;
1064
1065         if (TRACE_ABC_REMOVAL) {
1066                 printf ("\nProcessing block %d [dfn %d]...\n", bb->block_num, bb->dfn);
1067         }
1068
1069         if (bb->region != -1)
1070                 return;
1071
1072         get_relations_from_previous_bb (area, bb, &additional_relations);
1073         if (TRACE_ABC_REMOVAL) {
1074                 if (additional_relations.relation1.relation.relation != MONO_ANY_RELATION) {
1075                         printf ("Adding relation 1 on variable %d: ", additional_relations.relation1.variable);
1076                         print_summarized_value_relation (&(additional_relations.relation1.relation));
1077                         printf ("\n");
1078                 }
1079                 if (additional_relations.relation2.relation.relation != MONO_ANY_RELATION) {
1080                         printf ("Adding relation 2 on variable %d: ", additional_relations.relation2.variable);
1081                         print_summarized_value_relation (&(additional_relations.relation2.relation));
1082                         printf ("\n");
1083                 }
1084         }
1085         apply_change_to_evaluation_area (area, &(additional_relations.relation1));
1086         apply_change_to_evaluation_area (area, &(additional_relations.relation2));
1087
1088         inst_index = 0;
1089         for (ins = bb->code; ins; ins = ins->next) {
1090                 MonoAdditionalVariableRelation *rel;
1091                 int array_var, index_var;
1092
1093                 if (TRACE_ABC_REMOVAL) {
1094                         printf ("Processing instruction %d\n", inst_index);
1095                         inst_index++;
1096                 }
1097
1098                 if (ins->opcode == OP_BOUNDS_CHECK) { /* Handle OP_LDELEMA2D, too */
1099                         if (TRACE_ABC_REMOVAL) {
1100                                 printf ("Attempting check removal...\n");
1101                         }
1102
1103                         array_var = ins->sreg1;
1104                         index_var = ins->sreg2;
1105
1106                         remove_abc_from_inst (ins, area);
1107
1108                         /* We can derive additional relations from the bounds check */
1109                         if (ins->opcode != OP_NOP) {
1110                                 rel = (MonoAdditionalVariableRelation *)mono_mempool_alloc0 (cfg->mempool, sizeof (MonoAdditionalVariableRelation));
1111                                 rel->variable = index_var;
1112                                 rel->relation.relation = MONO_LT_RELATION;
1113                                 rel->relation.related_value.type = MONO_VARIABLE_SUMMARIZED_VALUE;
1114                                 rel->relation.related_value.value.variable.variable = array_var;
1115                                 rel->relation.related_value.value.variable.delta = 0;
1116
1117                                 apply_change_to_evaluation_area (area, rel);
1118
1119                                 check_relations = g_slist_append_mempool (cfg->mempool, check_relations, rel);
1120
1121                                 rel = (MonoAdditionalVariableRelation *)mono_mempool_alloc0 (cfg->mempool, sizeof (MonoAdditionalVariableRelation));
1122                                 rel->variable = index_var;
1123                                 rel->relation.relation = MONO_GE_RELATION;
1124                                 rel->relation.related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
1125                                 rel->relation.related_value.value.constant.value = 0;
1126
1127                                 apply_change_to_evaluation_area (area, rel);
1128
1129                                 check_relations = g_slist_append_mempool (cfg->mempool, check_relations, rel);
1130                         }
1131                 }
1132
1133                 if (ins->opcode == OP_CHECK_THIS) {
1134                         if (eval_non_null (area, ins->sreg1)) {
1135                                 if (REPORT_ABC_REMOVAL)
1136                                         printf ("ARRAY-ACCESS: removed check_this instruction.\n");
1137                                 NULLIFY_INS (ins);
1138                         }
1139                 }
1140
1141                 if (ins->opcode == OP_NOT_NULL)
1142                         add_non_null (area, cfg, ins->sreg1, &check_relations);
1143
1144                 /*
1145                  * FIXME: abcrem equates an array with its length,
1146                  * so a = new int [100] implies a != null, but a = new int [0] doesn't.
1147                  */
1148                 /*
1149                  * Eliminate MONO_INST_FAULT flags if possible.
1150                  */
1151                 if (COMPILE_LLVM (cfg) && (ins->opcode == OP_LDLEN ||
1152                                                                    ins->opcode == OP_BOUNDS_CHECK ||
1153                                                                    ins->opcode == OP_STRLEN ||
1154                                                                    (MONO_IS_LOAD_MEMBASE (ins) && (ins->flags & MONO_INST_FAULT)) ||
1155                                                                    (MONO_IS_STORE_MEMBASE (ins) && (ins->flags & MONO_INST_FAULT)))) {
1156                         int reg;
1157
1158                         if (MONO_IS_STORE_MEMBASE (ins))
1159                                 reg = ins->inst_destbasereg;
1160                         else if (MONO_IS_LOAD_MEMBASE (ins))
1161                                 reg = ins->inst_basereg;
1162                         else
1163                                 reg = ins->sreg1;
1164
1165                         /*
1166                          * This doesn't work because LLVM can move the non-faulting loads before the faulting
1167                          * ones (test_0_llvm_moving_faulting_loads ()).
1168                          * So only do it if we know the load cannot be moved before the instruction which ensures it is not
1169                          * null (i.e. the def of its sreg).
1170                          */
1171                         if (area->defs [reg] && area->defs [reg]->opcode == OP_NEWARR) {
1172                                 if (REPORT_ABC_REMOVAL)
1173                                         printf ("ARRAY-ACCESS: removed MONO_INST_FAULT flag.\n");
1174                                 ins->flags &= ~MONO_INST_FAULT;
1175                         }
1176                         /*
1177                         if (eval_non_null (area, reg)) {
1178                                 if (REPORT_ABC_REMOVAL)
1179                                         printf ("ARRAY-ACCESS: removed MONO_INST_FAULT flag.\n");
1180                                 ins->flags &= ~MONO_INST_FAULT;
1181                         } else {
1182                                 add_non_null (area, cfg, reg, &check_relations);
1183                         }
1184                         */
1185                 }
1186         }
1187
1188         if (TRACE_ABC_REMOVAL) {
1189                 printf ("Processing block %d [dfn %d] done.\n", bb->block_num, bb->dfn);
1190         }
1191
1192         for (dominated_bb = bb->dominated; dominated_bb != NULL; dominated_bb = dominated_bb->next) {
1193                 process_block (cfg, (MonoBasicBlock*) (dominated_bb->data), area);
1194         }
1195
1196         for (l = check_relations; l; l = l->next)
1197                 remove_change_from_evaluation_area ((MonoAdditionalVariableRelation *)l->data);
1198
1199         remove_change_from_evaluation_area (&(additional_relations.relation1));
1200         remove_change_from_evaluation_area (&(additional_relations.relation2));
1201 }
1202
1203 static MonoIntegerValueKind
1204 type_to_value_kind (MonoType *type)
1205 {
1206         if (type->byref)
1207                 return MONO_UNKNOWN_INTEGER_VALUE;
1208         switch (type->type) {
1209         case MONO_TYPE_I1:
1210                 return MONO_INTEGER_VALUE_SIZE_1;
1211                 break;
1212         case MONO_TYPE_U1:
1213                 return MONO_UNSIGNED_INTEGER_VALUE_SIZE_1;
1214                 break;
1215         case MONO_TYPE_I2:
1216                 return MONO_INTEGER_VALUE_SIZE_2;
1217                 break;
1218         case MONO_TYPE_U2:
1219                 return MONO_UNSIGNED_INTEGER_VALUE_SIZE_2;
1220                 break;
1221         case MONO_TYPE_I4:
1222                 return MONO_INTEGER_VALUE_SIZE_4;
1223                 break;
1224         case MONO_TYPE_U4:
1225                 return MONO_UNSIGNED_INTEGER_VALUE_SIZE_4;
1226                 break;
1227         case MONO_TYPE_I:
1228                 return (MonoIntegerValueKind)SIZEOF_VOID_P;
1229                 break;
1230         case MONO_TYPE_U:
1231                 return (MonoIntegerValueKind)(MONO_UNSIGNED_VALUE_FLAG | SIZEOF_VOID_P);
1232                 break;
1233         case MONO_TYPE_I8:
1234                 return MONO_INTEGER_VALUE_SIZE_8;
1235                 break;
1236         case MONO_TYPE_U8:
1237                 return MONO_UNSIGNED_INTEGER_VALUE_SIZE_8;
1238         default:
1239                 return MONO_UNKNOWN_INTEGER_VALUE;
1240         }
1241 }
1242
1243 /**
1244  * mono_perform_abc_removal:
1245  * @cfg: Control Flow Graph
1246  *
1247  * Performs the ABC removal from a cfg in SSA form.
1248  * It does the following:
1249  * - Prepare the evaluation area
1250  * - Allocate memory for the relation graph in the evaluation area
1251  *   (of course, only for variable definitions) and summarize there all
1252  *   variable definitions
1253  * - Allocate memory for the evaluation contexts in the evaluation area
1254  * - Recursively process all the BBs in the dominator tree (it is enough
1255  *   to invoke the processing on the entry BB)
1256  *
1257  * cfg: the method code
1258  */
1259 void
1260 mono_perform_abc_removal (MonoCompile *cfg)
1261 {
1262         MonoVariableRelationsEvaluationArea area;
1263         MonoBasicBlock *bb;
1264         int i;
1265
1266         verbose_level = cfg->verbose_level;
1267
1268         if (TRACE_ABC_REMOVAL) {
1269                 printf ("\nRemoving array bound checks in %s\n", mono_method_full_name (cfg->method, TRUE));
1270         }
1271
1272         area.cfg = cfg;
1273         area.relations = (MonoSummarizedValueRelation *)
1274                 mono_mempool_alloc (cfg->mempool, sizeof (MonoSummarizedValueRelation) * (cfg->next_vreg) * 2);
1275
1276         area.contexts = (MonoRelationsEvaluationContext *)
1277                 mono_mempool_alloc0 (cfg->mempool, sizeof (MonoRelationsEvaluationContext) * (cfg->next_vreg));
1278
1279         area.statuses = (MonoRelationsEvaluationStatus *)
1280                 mono_mempool_alloc0 (cfg->mempool, sizeof (MonoRelationsEvaluationStatus) * (cfg->next_vreg));
1281
1282         area.variable_value_kind = (MonoIntegerValueKind *)
1283                 mono_mempool_alloc (cfg->mempool, sizeof (MonoIntegerValueKind) * (cfg->next_vreg));
1284         area.defs = (MonoInst **)mono_mempool_alloc (cfg->mempool, sizeof (MonoInst*) * cfg->next_vreg);
1285         for (i = 0; i < cfg->next_vreg; i++) {
1286                 area.variable_value_kind [i] = MONO_UNKNOWN_INTEGER_VALUE;
1287                 area.relations [i].relation = MONO_EQ_RELATION;
1288                 area.relations [i].relation_is_static_definition = TRUE;
1289                 MAKE_VALUE_ANY (area.relations [i].related_value);
1290                 area.relations [i].next = NULL;
1291                 area.defs [i] = NULL;
1292         }
1293
1294         for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
1295                 MonoInst *ins;
1296
1297                 if (TRACE_ABC_REMOVAL)
1298                         printf ("\nABCREM BLOCK %d:\n", bb->block_num);
1299
1300                 for (ins = bb->code; ins; ins = ins->next) {
1301                         const char *spec = INS_INFO (ins->opcode);
1302
1303                         if (spec [MONO_INST_DEST] == ' ' || MONO_IS_STORE_MEMBASE (ins))
1304                                 continue;
1305
1306                         if (spec [MONO_INST_DEST] == 'i') {
1307                                 MonoIntegerValueKind effective_value_kind;
1308                                 MonoRelationsEvaluationRange range;
1309                                 MonoSummarizedValueRelation *type_relation;
1310                                 MonoInst *var;
1311
1312                                 if (TRACE_ABC_REMOVAL)
1313                                         mono_print_ins (ins);
1314
1315                                 var = get_vreg_to_inst (cfg, ins->dreg);
1316                                 if (var)
1317                                         area.variable_value_kind [ins->dreg] = type_to_value_kind (var->inst_vtype);
1318
1319                                 effective_value_kind = get_relation_from_ins (&area, ins, &area.relations [ins->dreg], area.variable_value_kind [ins->dreg]);
1320
1321                                 MONO_MAKE_RELATIONS_EVALUATION_RANGE_WEAK (range);
1322                                 apply_value_kind_to_range (&range, area.variable_value_kind [ins->dreg]);
1323                                 apply_value_kind_to_range (&range, effective_value_kind);
1324
1325                                 if (range.upper < INT_MAX) {
1326                                         type_relation = (MonoSummarizedValueRelation *) mono_mempool_alloc (cfg->mempool, sizeof (MonoSummarizedValueRelation));
1327                                         type_relation->relation = MONO_LE_RELATION;
1328                                         type_relation->related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
1329                                         type_relation->related_value.value.constant.value = range.upper;
1330                                         type_relation->relation_is_static_definition = TRUE;
1331                                         type_relation->next = area.relations [ins->dreg].next;
1332                                         area.relations [ins->dreg].next = type_relation;
1333                                         if (TRACE_ABC_REMOVAL) {
1334                                                 printf ("[var%d <= %d]", ins->dreg, range.upper);
1335                                         }
1336                                 }
1337                                 if (range.lower > INT_MIN) {
1338                                         type_relation = (MonoSummarizedValueRelation *) mono_mempool_alloc (cfg->mempool, sizeof (MonoSummarizedValueRelation));
1339                                         type_relation->relation = MONO_GE_RELATION;
1340                                         type_relation->related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
1341                                         type_relation->related_value.value.constant.value = range.lower;
1342                                         type_relation->relation_is_static_definition = TRUE;
1343                                         type_relation->next = area.relations [ins->dreg].next;
1344                                         area.relations [ins->dreg].next = type_relation;
1345                                         if (TRACE_ABC_REMOVAL) {
1346                                                 printf ("[var%d >= %d]", ins->dreg, range.lower);
1347                                         }
1348                                 }
1349                                 if (TRACE_ABC_REMOVAL) {
1350                                         printf ("Summarized variable %d: ", ins->dreg);
1351                                         print_summarized_value (&(area.relations [ins->dreg].related_value));
1352                                         printf ("\n");
1353                                 }
1354                         }
1355                 }
1356         }
1357
1358         /* Add symmetric relations */
1359         for (i = 0; i < cfg->next_vreg; i++) {
1360                 if (area.relations [i].related_value.type == MONO_VARIABLE_SUMMARIZED_VALUE) {
1361                         int related_index = cfg->next_vreg + i;
1362                         int related_variable = area.relations [i].related_value.value.variable.variable;
1363
1364                         area.relations [related_index].relation = MONO_EQ_RELATION;
1365                         area.relations [related_index].relation_is_static_definition = TRUE;
1366                         area.relations [related_index].related_value.type = MONO_VARIABLE_SUMMARIZED_VALUE;
1367                         area.relations [related_index].related_value.value.variable.variable = i;
1368                         area.relations [related_index].related_value.value.variable.delta = - area.relations [i].related_value.value.variable.delta;
1369
1370                         area.relations [related_index].next = area.relations [related_variable].next;
1371                         area.relations [related_variable].next = &(area.relations [related_index]);
1372
1373                         if (TRACE_ABC_REMOVAL) {
1374                                 printf ("Added symmetric summarized value for variable variable %d (to %d): ", i, related_variable);
1375                                 print_summarized_value (&(area.relations [related_index].related_value));
1376                                 printf ("\n");
1377                         }
1378                 }
1379         }
1380
1381         process_block (cfg, cfg->bblocks [0], &area);
1382 }
1383
1384 #else /* !DISABLE_JIT */
1385
1386 MONO_EMPTY_SOURCE_FILE (abcremoval);
1387
1388 #endif /* !DISABLE_JIT */