1 /* 2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "c1/c1_Canonicalizer.hpp" 27 #include "c1/c1_InstructionPrinter.hpp" 28 #include "c1/c1_ValueStack.hpp" 29 #include "ci/ciArray.hpp" 30 #include "runtime/sharedRuntime.hpp" 31 32 33 class PrintValueVisitor: public ValueVisitor { 34 void visit(Value* vp) { 35 (*vp)->print_line(); 36 } 37 }; 38 39 void Canonicalizer::set_canonical(Value x) { 40 assert(x != NULL, "value must exist"); 41 // Note: we can not currently substitute root nodes which show up in 42 // the instruction stream (because the instruction list is embedded 43 // in the instructions). 44 if (canonical() != x) { 45 #ifndef PRODUCT 46 if (!x->has_printable_bci()) { 47 x->set_printable_bci(bci()); 48 } 49 #endif 50 if (PrintCanonicalization) { 51 PrintValueVisitor do_print_value; 52 canonical()->input_values_do(&do_print_value); 53 canonical()->print_line(); 54 tty->print_cr("canonicalized to:"); 55 x->input_values_do(&do_print_value); 56 x->print_line(); 57 tty->cr(); 58 } 59 assert(_canonical->type()->tag() == x->type()->tag(), "types must match"); 60 _canonical = x; 61 } 62 } 63 64 65 void Canonicalizer::move_const_to_right(Op2* x) { 66 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands(); 67 } 68 69 70 void Canonicalizer::do_Op2(Op2* x) { 71 if (x->x() == x->y()) { 72 switch (x->op()) { 73 case Bytecodes::_isub: set_constant(0); return; 74 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return; 75 case Bytecodes::_iand: // fall through 76 case Bytecodes::_land: // fall through 77 case Bytecodes::_ior : // fall through 78 case Bytecodes::_lor : set_canonical(x->x()); return; 79 case Bytecodes::_ixor: set_constant(0); return; 80 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return; 81 default : break; 82 } 83 } 84 85 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) { 86 // do constant folding for selected operations 87 switch (x->type()->tag()) { 88 case intTag: 89 { jint a = x->x()->type()->as_IntConstant()->value(); 90 jint b = x->y()->type()->as_IntConstant()->value(); 91 switch (x->op()) { 92 case Bytecodes::_iadd: set_constant(a + b); return; 93 case Bytecodes::_isub: set_constant(a - b); return; 94 case Bytecodes::_imul: set_constant(a * b); return; 95 case Bytecodes::_idiv: 96 if (b != 0) { 97 if (a == min_jint && b == -1) { 98 set_constant(min_jint); 99 } else { 100 set_constant(a / b); 101 } 102 return; 103 } 104 break; 105 case Bytecodes::_irem: 106 if (b != 0) { 107 if (a == min_jint && b == -1) { 108 set_constant(0); 109 } else { 110 set_constant(a % b); 111 } 112 return; 113 } 114 break; 115 case Bytecodes::_iand: set_constant(a & b); return; 116 case Bytecodes::_ior : set_constant(a | b); return; 117 case Bytecodes::_ixor: set_constant(a ^ b); return; 118 default : break; 119 } 120 } 121 break; 122 case longTag: 123 { jlong a = x->x()->type()->as_LongConstant()->value(); 124 jlong b = x->y()->type()->as_LongConstant()->value(); 125 switch (x->op()) { 126 case Bytecodes::_ladd: set_constant(a + b); return; 127 case Bytecodes::_lsub: set_constant(a - b); return; 128 case Bytecodes::_lmul: set_constant(a * b); return; 129 case Bytecodes::_ldiv: 130 if (b != 0) { 131 set_constant(SharedRuntime::ldiv(b, a)); 132 return; 133 } 134 break; 135 case Bytecodes::_lrem: 136 if (b != 0) { 137 set_constant(SharedRuntime::lrem(b, a)); 138 return; 139 } 140 break; 141 case Bytecodes::_land: set_constant(a & b); return; 142 case Bytecodes::_lor : set_constant(a | b); return; 143 case Bytecodes::_lxor: set_constant(a ^ b); return; 144 default : break; 145 } 146 } 147 break; 148 default: 149 // other cases not implemented (must be extremely careful with floats & doubles!) 150 break; 151 } 152 } 153 // make sure constant is on the right side, if any 154 move_const_to_right(x); 155 156 if (x->y()->type()->is_constant()) { 157 // do constant folding for selected operations 158 switch (x->type()->tag()) { 159 case intTag: 160 if (x->y()->type()->as_IntConstant()->value() == 0) { 161 switch (x->op()) { 162 case Bytecodes::_iadd: set_canonical(x->x()); return; 163 case Bytecodes::_isub: set_canonical(x->x()); return; 164 case Bytecodes::_imul: set_constant(0); return; 165 // Note: for div and rem, make sure that C semantics 166 // corresponds to Java semantics! 167 case Bytecodes::_iand: set_constant(0); return; 168 case Bytecodes::_ior : set_canonical(x->x()); return; 169 default : break; 170 } 171 } 172 break; 173 case longTag: 174 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) { 175 switch (x->op()) { 176 case Bytecodes::_ladd: set_canonical(x->x()); return; 177 case Bytecodes::_lsub: set_canonical(x->x()); return; 178 case Bytecodes::_lmul: set_constant((jlong)0); return; 179 // Note: for div and rem, make sure that C semantics 180 // corresponds to Java semantics! 181 case Bytecodes::_land: set_constant((jlong)0); return; 182 case Bytecodes::_lor : set_canonical(x->x()); return; 183 default : break; 184 } 185 } 186 break; 187 default: 188 break; 189 } 190 } 191 } 192 193 194 void Canonicalizer::do_Phi (Phi* x) {} 195 void Canonicalizer::do_Constant (Constant* x) {} 196 void Canonicalizer::do_Local (Local* x) {} 197 void Canonicalizer::do_LoadField (LoadField* x) {} 198 199 // checks if v is in the block that is currently processed by 200 // GraphBuilder. This is the only block that has not BlockEnd yet. 201 static bool in_current_block(Value v) { 202 int max_distance = 4; 203 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) { 204 v = v->next(); 205 max_distance--; 206 } 207 return v == NULL; 208 } 209 210 void Canonicalizer::do_StoreField (StoreField* x) { 211 // If a value is going to be stored into a field or array some of 212 // the conversions emitted by javac are unneeded because the fields 213 // are packed to their natural size. 214 Convert* conv = x->value()->as_Convert(); 215 if (conv) { 216 Value value = NULL; 217 BasicType type = x->field()->type()->basic_type(); 218 switch (conv->op()) { 219 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break; 220 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break; 221 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break; 222 default : break; 223 } 224 // limit this optimization to current block 225 if (value != NULL && in_current_block(conv)) { 226 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(), 227 x->state_before(), x->needs_patching())); 228 return; 229 } 230 } 231 232 } 233 234 void Canonicalizer::do_ArrayLength (ArrayLength* x) { 235 NewArray* na; 236 Constant* ct; 237 LoadField* lf; 238 239 if ((na = x->array()->as_NewArray()) != NULL) { 240 // New arrays might have the known length. 241 // Do not use the Constant itself, but create a new Constant 242 // with same value Otherwise a Constant is live over multiple 243 // blocks without being registered in a state array. 244 Constant* length; 245 if (na->length() != NULL && 246 (length = na->length()->as_Constant()) != NULL) { 247 assert(length->type()->as_IntConstant() != NULL, "array length must be integer"); 248 set_constant(length->type()->as_IntConstant()->value()); 249 } 250 251 } else if ((ct = x->array()->as_Constant()) != NULL) { 252 // Constant arrays have constant lengths. 253 ArrayConstant* cnst = ct->type()->as_ArrayConstant(); 254 if (cnst != NULL) { 255 set_constant(cnst->value()->length()); 256 } 257 258 } else if ((lf = x->array()->as_LoadField()) != NULL) { 259 ciField* field = lf->field(); 260 if (field->is_static_constant()) { 261 // Constant field loads are usually folded during parsing. 262 // But it doesn't happen with PatchALot, ScavengeRootsInCode < 2, or when 263 // holder class is being initialized during parsing (for static fields). 264 ciObject* c = field->constant_value().as_object(); 265 if (!c->is_null_object()) { 266 set_constant(c->as_array()->length()); 267 } 268 } 269 } 270 } 271 272 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) { 273 StableArrayConstant* array = x->array()->type()->as_StableArrayConstant(); 274 IntConstant* index = x->index()->type()->as_IntConstant(); 275 276 assert(array == NULL || FoldStableValues, "not enabled"); 277 278 // Constant fold loads from stable arrays. 279 if (!x->mismatched() && array != NULL && index != NULL) { 280 jint idx = index->value(); 281 if (idx < 0 || idx >= array->value()->length()) { 282 // Leave the load as is. The range check will handle it. 283 return; 284 } 285 286 ciConstant field_val = array->value()->element_value(idx); 287 if (!field_val.is_null_or_zero()) { 288 jint dimension = array->dimension(); 289 assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info"); 290 ValueType* value = NULL; 291 if (dimension > 1) { 292 // Preserve information about the dimension for the element. 293 assert(field_val.as_object()->is_array(), "not an array"); 294 value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1); 295 } else { 296 assert(dimension == 1, "sanity"); 297 value = as_ValueType(field_val); 298 } 299 set_canonical(new Constant(value)); 300 } 301 } 302 } 303 304 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) { 305 // If a value is going to be stored into a field or array some of 306 // the conversions emitted by javac are unneeded because the fields 307 // are packed to their natural size. 308 Convert* conv = x->value()->as_Convert(); 309 if (conv) { 310 Value value = NULL; 311 BasicType type = x->elt_type(); 312 switch (conv->op()) { 313 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break; 314 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break; 315 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break; 316 default : break; 317 } 318 // limit this optimization to current block 319 if (value != NULL && in_current_block(conv)) { 320 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(), 321 x->elt_type(), value, x->state_before(), 322 x->check_boolean())); 323 return; 324 } 325 } 326 } 327 328 329 void Canonicalizer::do_NegateOp(NegateOp* x) { 330 ValueType* t = x->x()->type(); 331 if (t->is_constant()) { 332 switch (t->tag()) { 333 case intTag : set_constant(-t->as_IntConstant ()->value()); return; 334 case longTag : set_constant(-t->as_LongConstant ()->value()); return; 335 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return; 336 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return; 337 default : ShouldNotReachHere(); 338 } 339 } 340 } 341 342 343 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); } 344 345 346 void Canonicalizer::do_ShiftOp (ShiftOp* x) { 347 ValueType* t = x->x()->type(); 348 ValueType* t2 = x->y()->type(); 349 if (t->is_constant()) { 350 switch (t->tag()) { 351 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break; 352 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break; 353 default : ShouldNotReachHere(); 354 } 355 if (t2->is_constant()) { 356 if (t->tag() == intTag) { 357 int value = t->as_IntConstant()->value(); 358 int shift = t2->as_IntConstant()->value() & 31; 359 jint mask = ~(~0 << (32 - shift)); 360 if (shift == 0) mask = ~0; 361 switch (x->op()) { 362 case Bytecodes::_ishl: set_constant(value << shift); return; 363 case Bytecodes::_ishr: set_constant(value >> shift); return; 364 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return; 365 default: break; 366 } 367 } else if (t->tag() == longTag) { 368 jlong value = t->as_LongConstant()->value(); 369 int shift = t2->as_IntConstant()->value() & 63; 370 jlong mask = ~(~jlong_cast(0) << (64 - shift)); 371 if (shift == 0) mask = ~jlong_cast(0); 372 switch (x->op()) { 373 case Bytecodes::_lshl: set_constant(value << shift); return; 374 case Bytecodes::_lshr: set_constant(value >> shift); return; 375 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return; 376 default: break; 377 } 378 } 379 } 380 } 381 if (t2->is_constant()) { 382 switch (t2->tag()) { 383 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return; 384 case longTag : if (t2->as_LongConstant()->value() == (jlong)0) set_canonical(x->x()); return; 385 default : ShouldNotReachHere(); return; 386 } 387 } 388 } 389 390 391 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); } 392 void Canonicalizer::do_CompareOp (CompareOp* x) { 393 if (x->x() == x->y()) { 394 switch (x->x()->type()->tag()) { 395 case longTag: set_constant(0); break; 396 case floatTag: { 397 FloatConstant* fc = x->x()->type()->as_FloatConstant(); 398 if (fc) { 399 if (g_isnan(fc->value())) { 400 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1); 401 } else { 402 set_constant(0); 403 } 404 } 405 break; 406 } 407 case doubleTag: { 408 DoubleConstant* dc = x->x()->type()->as_DoubleConstant(); 409 if (dc) { 410 if (g_isnan(dc->value())) { 411 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1); 412 } else { 413 set_constant(0); 414 } 415 } 416 break; 417 } 418 default: 419 break; 420 } 421 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) { 422 switch (x->x()->type()->tag()) { 423 case longTag: { 424 jlong vx = x->x()->type()->as_LongConstant()->value(); 425 jlong vy = x->y()->type()->as_LongConstant()->value(); 426 if (vx == vy) 427 set_constant(0); 428 else if (vx < vy) 429 set_constant(-1); 430 else 431 set_constant(1); 432 break; 433 } 434 435 case floatTag: { 436 float vx = x->x()->type()->as_FloatConstant()->value(); 437 float vy = x->y()->type()->as_FloatConstant()->value(); 438 if (g_isnan(vx) || g_isnan(vy)) 439 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1); 440 else if (vx == vy) 441 set_constant(0); 442 else if (vx < vy) 443 set_constant(-1); 444 else 445 set_constant(1); 446 break; 447 } 448 449 case doubleTag: { 450 double vx = x->x()->type()->as_DoubleConstant()->value(); 451 double vy = x->y()->type()->as_DoubleConstant()->value(); 452 if (g_isnan(vx) || g_isnan(vy)) 453 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1); 454 else if (vx == vy) 455 set_constant(0); 456 else if (vx < vy) 457 set_constant(-1); 458 else 459 set_constant(1); 460 break; 461 } 462 463 default: 464 break; 465 } 466 } 467 } 468 469 470 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {} 471 472 void Canonicalizer::do_IfOp(IfOp* x) { 473 // Caution: do not use do_Op2(x) here for now since 474 // we map the condition to the op for now! 475 move_const_to_right(x); 476 } 477 478 479 void Canonicalizer::do_Intrinsic (Intrinsic* x) { 480 switch (x->id()) { 481 case vmIntrinsics::_floatToRawIntBits : { 482 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant(); 483 if (c != NULL) { 484 JavaValue v; 485 v.set_jfloat(c->value()); 486 set_constant(v.get_jint()); 487 } 488 break; 489 } 490 case vmIntrinsics::_intBitsToFloat : { 491 IntConstant* c = x->argument_at(0)->type()->as_IntConstant(); 492 if (c != NULL) { 493 JavaValue v; 494 v.set_jint(c->value()); 495 set_constant(v.get_jfloat()); 496 } 497 break; 498 } 499 case vmIntrinsics::_doubleToRawLongBits : { 500 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant(); 501 if (c != NULL) { 502 JavaValue v; 503 v.set_jdouble(c->value()); 504 set_constant(v.get_jlong()); 505 } 506 break; 507 } 508 case vmIntrinsics::_longBitsToDouble : { 509 LongConstant* c = x->argument_at(0)->type()->as_LongConstant(); 510 if (c != NULL) { 511 JavaValue v; 512 v.set_jlong(c->value()); 513 set_constant(v.get_jdouble()); 514 } 515 break; 516 } 517 case vmIntrinsics::_isInstance : { 518 assert(x->number_of_arguments() == 2, "wrong type"); 519 520 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant(); 521 if (c != NULL && !c->value()->is_null_object()) { 522 // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors 523 ciType* t = c->value()->java_mirror_type(); 524 if (t->is_klass()) { 525 // substitute cls.isInstance(obj) of a constant Class into 526 // an InstantOf instruction 527 InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before()); 528 set_canonical(i); 529 // and try to canonicalize even further 530 do_InstanceOf(i); 531 } else { 532 assert(t->is_primitive_type(), "should be a primitive type"); 533 // cls.isInstance(obj) always returns false for primitive classes 534 set_constant(0); 535 } 536 } 537 break; 538 } 539 case vmIntrinsics::_isPrimitive : { 540 assert(x->number_of_arguments() == 1, "wrong type"); 541 542 // Class.isPrimitive is known on constant classes: 543 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant(); 544 if (c != NULL && !c->value()->is_null_object()) { 545 ciType* t = c->value()->java_mirror_type(); 546 set_constant(t->is_primitive_type()); 547 } 548 break; 549 } 550 default: 551 break; 552 } 553 } 554 555 void Canonicalizer::do_Convert (Convert* x) { 556 if (x->value()->type()->is_constant()) { 557 switch (x->op()) { 558 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break; 559 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break; 560 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break; 561 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break; 562 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break; 563 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break; 564 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break; 565 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break; 566 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break; 567 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break; 568 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break; 569 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break; 570 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break; 571 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break; 572 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break; 573 default: 574 ShouldNotReachHere(); 575 } 576 } 577 578 Value value = x->value(); 579 BasicType type = T_ILLEGAL; 580 LoadField* lf = value->as_LoadField(); 581 if (lf) { 582 type = lf->field_type(); 583 } else { 584 LoadIndexed* li = value->as_LoadIndexed(); 585 if (li) { 586 type = li->elt_type(); 587 } else { 588 Convert* conv = value->as_Convert(); 589 if (conv) { 590 switch (conv->op()) { 591 case Bytecodes::_i2b: type = T_BYTE; break; 592 case Bytecodes::_i2s: type = T_SHORT; break; 593 case Bytecodes::_i2c: type = T_CHAR; break; 594 default : break; 595 } 596 } 597 } 598 } 599 if (type != T_ILLEGAL) { 600 switch (x->op()) { 601 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break; 602 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break; 603 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break; 604 default : break; 605 } 606 } else { 607 Op2* op2 = x->value()->as_Op2(); 608 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) { 609 jint safebits = 0; 610 jint mask = op2->y()->type()->as_IntConstant()->value(); 611 switch (x->op()) { 612 case Bytecodes::_i2b: safebits = 0x7f; break; 613 case Bytecodes::_i2s: safebits = 0x7fff; break; 614 case Bytecodes::_i2c: safebits = 0xffff; break; 615 default : break; 616 } 617 // When casting a masked integer to a smaller signed type, if 618 // the mask doesn't include the sign bit the cast isn't needed. 619 if (safebits && (mask & ~safebits) == 0) { 620 set_canonical(x->value()); 621 } 622 } 623 } 624 625 } 626 627 void Canonicalizer::do_NullCheck (NullCheck* x) { 628 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) { 629 set_canonical(x->obj()); 630 } else { 631 Constant* con = x->obj()->as_Constant(); 632 if (con) { 633 ObjectType* c = con->type()->as_ObjectType(); 634 if (c && c->is_loaded()) { 635 ObjectConstant* oc = c->as_ObjectConstant(); 636 if (!oc || !oc->value()->is_null_object()) { 637 set_canonical(con); 638 } 639 } 640 } 641 } 642 } 643 644 void Canonicalizer::do_TypeCast (TypeCast* x) {} 645 void Canonicalizer::do_Invoke (Invoke* x) {} 646 void Canonicalizer::do_NewInstance (NewInstance* x) {} 647 void Canonicalizer::do_NewValueTypeInstance(NewValueTypeInstance* x) {} 648 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {} 649 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {} 650 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {} 651 void Canonicalizer::do_WithField (WithField* x) {} 652 void Canonicalizer::do_DefaultValue (DefaultValue* x) {} 653 void Canonicalizer::do_CheckCast (CheckCast* x) { 654 if (x->klass()->is_loaded() && !x->is_never_null()) { 655 // Don't canonicalize for non-nullable types -- we need to throw NPE. 656 Value obj = x->obj(); 657 ciType* klass = obj->exact_type(); 658 if (klass == NULL) { 659 klass = obj->declared_type(); 660 } 661 if (klass != NULL && klass->is_loaded()) { 662 bool is_interface = klass->is_instance_klass() && 663 klass->as_instance_klass()->is_interface(); 664 // Interface casts can't be statically optimized away since verifier doesn't 665 // enforce interface types in bytecode. 666 if (!is_interface && klass->is_subtype_of(x->klass())) { 667 set_canonical(obj); 668 return; 669 } 670 } 671 // checkcast of null returns null 672 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) { 673 set_canonical(obj); 674 } 675 } 676 } 677 void Canonicalizer::do_InstanceOf (InstanceOf* x) { 678 if (x->klass()->is_loaded()) { 679 Value obj = x->obj(); 680 ciType* exact = obj->exact_type(); 681 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) { 682 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0); 683 return; 684 } 685 // instanceof null returns false 686 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) { 687 set_constant(0); 688 } 689 } 690 691 } 692 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {} 693 void Canonicalizer::do_MonitorExit (MonitorExit* x) {} 694 void Canonicalizer::do_BlockBegin (BlockBegin* x) {} 695 void Canonicalizer::do_Goto (Goto* x) {} 696 697 698 static bool is_true(jlong x, If::Condition cond, jlong y) { 699 switch (cond) { 700 case If::eql: return x == y; 701 case If::neq: return x != y; 702 case If::lss: return x < y; 703 case If::leq: return x <= y; 704 case If::gtr: return x > y; 705 case If::geq: return x >= y; 706 default: 707 ShouldNotReachHere(); 708 return false; 709 } 710 } 711 712 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) { 713 // An Instruction with multiple successors, x, is replaced by a Goto 714 // to a single successor, sux. Is a safepoint check needed = was the 715 // instruction being replaced a safepoint and the single remaining 716 // successor a back branch? 717 return x->is_safepoint() && (sux->bci() < x->state_before()->bci()); 718 } 719 720 void Canonicalizer::do_If(If* x) { 721 // move const to right 722 if (x->x()->type()->is_constant()) x->swap_operands(); 723 // simplify 724 const Value l = x->x(); ValueType* lt = l->type(); 725 const Value r = x->y(); ValueType* rt = r->type(); 726 727 if (l == r && !lt->is_float_kind()) { 728 // pattern: If (a cond a) => simplify to Goto 729 BlockBegin* sux = NULL; 730 switch (x->cond()) { 731 case If::eql: sux = x->sux_for(true); break; 732 case If::neq: sux = x->sux_for(false); break; 733 case If::lss: sux = x->sux_for(false); break; 734 case If::leq: sux = x->sux_for(true); break; 735 case If::gtr: sux = x->sux_for(false); break; 736 case If::geq: sux = x->sux_for(true); break; 737 default: ShouldNotReachHere(); 738 } 739 // If is a safepoint then the debug information should come from the state_before of the If. 740 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 741 return; 742 } 743 744 if (lt->is_constant() && rt->is_constant()) { 745 if (x->x()->as_Constant() != NULL) { 746 // pattern: If (lc cond rc) => simplify to: Goto 747 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(), 748 x->sux_for(true), 749 x->sux_for(false)); 750 if (sux != NULL) { 751 // If is a safepoint then the debug information should come from the state_before of the If. 752 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 753 } 754 } 755 } else if (rt->as_IntConstant() != NULL) { 756 // pattern: If (l cond rc) => investigate further 757 const jint rc = rt->as_IntConstant()->value(); 758 if (l->as_CompareOp() != NULL) { 759 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto 760 CompareOp* cmp = l->as_CompareOp(); 761 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl; 762 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b 763 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b 764 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b 765 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered 766 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are 767 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either 768 // lss_sux or gtr_sux. 769 if (lss_sux == eql_sux && eql_sux == gtr_sux) { 770 // all successors identical => simplify to: Goto 771 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint())); 772 } else { 773 // two successors differ and two successors are the same => simplify to: If (x cmp y) 774 // determine new condition & successors 775 If::Condition cond = If::eql; 776 BlockBegin* tsux = NULL; 777 BlockBegin* fsux = NULL; 778 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; } 779 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; } 780 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; } 781 else { ShouldNotReachHere(); } 782 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint()); 783 if (cmp->x() == cmp->y()) { 784 do_If(canon); 785 } else { 786 if (compilation()->profile_branches() || compilation()->count_backedges()) { 787 // TODO: If profiling, leave floating point comparisons unoptimized. 788 // We currently do not support profiling of the unordered case. 789 switch(cmp->op()) { 790 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg: 791 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg: 792 set_canonical(x); 793 return; 794 default: 795 break; 796 } 797 } 798 set_bci(cmp->state_before()->bci()); 799 set_canonical(canon); 800 } 801 } 802 } else if (l->as_InstanceOf() != NULL) { 803 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf 804 // instruction in the graph (it is pinned). Need to fix this at some point. 805 // It should also be left in the graph when generating a profiled method version or Goto 806 // has to know that it was an InstanceOf. 807 return; 808 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto 809 InstanceOf* inst = l->as_InstanceOf(); 810 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1 811 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0 812 if (is_inst_sux == no_inst_sux && inst->is_loaded()) { 813 // both successors identical and klass is loaded => simplify to: Goto 814 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint())); 815 } else { 816 // successors differ => simplify to: IfInstanceOf 817 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux)); 818 } 819 } 820 } else if (rt == objectNull && 821 (l->as_NewInstance() || l->as_NewArray() || 822 (l->as_Local() && l->as_Local()->is_receiver()))) { 823 if (x->cond() == Instruction::eql) { 824 BlockBegin* sux = x->fsux(); 825 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 826 } else { 827 assert(x->cond() == Instruction::neq, "only other valid case"); 828 BlockBegin* sux = x->tsux(); 829 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 830 } 831 } 832 } 833 834 835 void Canonicalizer::do_TableSwitch(TableSwitch* x) { 836 if (x->tag()->type()->is_constant()) { 837 int v = x->tag()->type()->as_IntConstant()->value(); 838 BlockBegin* sux = x->default_sux(); 839 if (v >= x->lo_key() && v <= x->hi_key()) { 840 sux = x->sux_at(v - x->lo_key()); 841 } 842 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 843 } else if (x->number_of_sux() == 1) { 844 // NOTE: Code permanently disabled for now since the switch statement's 845 // tag expression may produce side-effects in which case it must 846 // be executed. 847 return; 848 // simplify to Goto 849 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint())); 850 } else if (x->number_of_sux() == 2) { 851 // NOTE: Code permanently disabled for now since it produces two new nodes 852 // (Constant & If) and the Canonicalizer cannot return them correctly 853 // yet. For now we copied the corresponding code directly into the 854 // GraphBuilder (i.e., we should never reach here). 855 return; 856 // simplify to If 857 assert(x->lo_key() == x->hi_key(), "keys must be the same"); 858 Constant* key = new Constant(new IntConstant(x->lo_key())); 859 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint())); 860 } 861 } 862 863 864 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) { 865 if (x->tag()->type()->is_constant()) { 866 int v = x->tag()->type()->as_IntConstant()->value(); 867 BlockBegin* sux = x->default_sux(); 868 for (int i = 0; i < x->length(); i++) { 869 if (v == x->key_at(i)) { 870 sux = x->sux_at(i); 871 } 872 } 873 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux))); 874 } else if (x->number_of_sux() == 1) { 875 // NOTE: Code permanently disabled for now since the switch statement's 876 // tag expression may produce side-effects in which case it must 877 // be executed. 878 return; 879 // simplify to Goto 880 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint())); 881 } else if (x->number_of_sux() == 2) { 882 // NOTE: Code permanently disabled for now since it produces two new nodes 883 // (Constant & If) and the Canonicalizer cannot return them correctly 884 // yet. For now we copied the corresponding code directly into the 885 // GraphBuilder (i.e., we should never reach here). 886 return; 887 // simplify to If 888 assert(x->length() == 1, "length must be the same"); 889 Constant* key = new Constant(new IntConstant(x->key_at(0))); 890 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint())); 891 } 892 } 893 894 895 void Canonicalizer::do_Return (Return* x) {} 896 void Canonicalizer::do_Throw (Throw* x) {} 897 void Canonicalizer::do_Base (Base* x) {} 898 void Canonicalizer::do_OsrEntry (OsrEntry* x) {} 899 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {} 900 901 static bool match_index_and_scale(Instruction* instr, 902 Instruction** index, 903 int* log2_scale) { 904 // Skip conversion ops. This works only on 32bit because of the implicit l2i that the 905 // unsafe performs. 906 #ifndef _LP64 907 Convert* convert = instr->as_Convert(); 908 if (convert != NULL && convert->op() == Bytecodes::_i2l) { 909 assert(convert->value()->type() == intType, "invalid input type"); 910 instr = convert->value(); 911 } 912 #endif 913 914 ShiftOp* shift = instr->as_ShiftOp(); 915 if (shift != NULL) { 916 if (shift->op() == Bytecodes::_lshl) { 917 assert(shift->x()->type() == longType, "invalid input type"); 918 } else { 919 #ifndef _LP64 920 if (shift->op() == Bytecodes::_ishl) { 921 assert(shift->x()->type() == intType, "invalid input type"); 922 } else { 923 return false; 924 } 925 #else 926 return false; 927 #endif 928 } 929 930 931 // Constant shift value? 932 Constant* con = shift->y()->as_Constant(); 933 if (con == NULL) return false; 934 // Well-known type and value? 935 IntConstant* val = con->type()->as_IntConstant(); 936 assert(val != NULL, "Should be an int constant"); 937 938 *index = shift->x(); 939 int tmp_scale = val->value(); 940 if (tmp_scale >= 0 && tmp_scale < 4) { 941 *log2_scale = tmp_scale; 942 return true; 943 } else { 944 return false; 945 } 946 } 947 948 ArithmeticOp* arith = instr->as_ArithmeticOp(); 949 if (arith != NULL) { 950 // See if either arg is a known constant 951 Constant* con = arith->x()->as_Constant(); 952 if (con != NULL) { 953 *index = arith->y(); 954 } else { 955 con = arith->y()->as_Constant(); 956 if (con == NULL) return false; 957 *index = arith->x(); 958 } 959 long const_value; 960 // Check for integer multiply 961 if (arith->op() == Bytecodes::_lmul) { 962 assert((*index)->type() == longType, "invalid input type"); 963 LongConstant* val = con->type()->as_LongConstant(); 964 assert(val != NULL, "expecting a long constant"); 965 const_value = val->value(); 966 } else { 967 #ifndef _LP64 968 if (arith->op() == Bytecodes::_imul) { 969 assert((*index)->type() == intType, "invalid input type"); 970 IntConstant* val = con->type()->as_IntConstant(); 971 assert(val != NULL, "expecting an int constant"); 972 const_value = val->value(); 973 } else { 974 return false; 975 } 976 #else 977 return false; 978 #endif 979 } 980 switch (const_value) { 981 case 1: *log2_scale = 0; return true; 982 case 2: *log2_scale = 1; return true; 983 case 4: *log2_scale = 2; return true; 984 case 8: *log2_scale = 3; return true; 985 default: return false; 986 } 987 } 988 989 // Unknown instruction sequence; don't touch it 990 return false; 991 } 992 993 994 static bool match(UnsafeRawOp* x, 995 Instruction** base, 996 Instruction** index, 997 int* log2_scale) { 998 ArithmeticOp* root = x->base()->as_ArithmeticOp(); 999 if (root == NULL) return false; 1000 // Limit ourselves to addition for now 1001 if (root->op() != Bytecodes::_ladd) return false; 1002 1003 bool match_found = false; 1004 // Try to find shift or scale op 1005 if (match_index_and_scale(root->y(), index, log2_scale)) { 1006 *base = root->x(); 1007 match_found = true; 1008 } else if (match_index_and_scale(root->x(), index, log2_scale)) { 1009 *base = root->y(); 1010 match_found = true; 1011 } else if (NOT_LP64(root->y()->as_Convert() != NULL) LP64_ONLY(false)) { 1012 // Skipping i2l works only on 32bit because of the implicit l2i that the unsafe performs. 1013 // 64bit needs a real sign-extending conversion. 1014 Convert* convert = root->y()->as_Convert(); 1015 if (convert->op() == Bytecodes::_i2l) { 1016 assert(convert->value()->type() == intType, "should be an int"); 1017 // pick base and index, setting scale at 1 1018 *base = root->x(); 1019 *index = convert->value(); 1020 *log2_scale = 0; 1021 match_found = true; 1022 } 1023 } 1024 // The default solution 1025 if (!match_found) { 1026 *base = root->x(); 1027 *index = root->y(); 1028 *log2_scale = 0; 1029 } 1030 1031 // If the value is pinned then it will be always be computed so 1032 // there's no profit to reshaping the expression. 1033 return !root->is_pinned(); 1034 } 1035 1036 1037 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) { 1038 Instruction* base = NULL; 1039 Instruction* index = NULL; 1040 int log2_scale; 1041 1042 if (match(x, &base, &index, &log2_scale)) { 1043 x->set_base(base); 1044 x->set_index(index); 1045 x->set_log2_scale(log2_scale); 1046 if (PrintUnsafeOptimization) { 1047 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d", 1048 x->id(), x->base()->id(), x->index()->id(), x->log2_scale()); 1049 } 1050 } 1051 } 1052 1053 void Canonicalizer::do_RoundFP(RoundFP* x) {} 1054 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); } 1055 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); } 1056 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {} 1057 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {} 1058 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {} 1059 void Canonicalizer::do_ProfileCall(ProfileCall* x) {} 1060 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {} 1061 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {} 1062 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {} 1063 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {} 1064 #ifdef ASSERT 1065 void Canonicalizer::do_Assert(Assert* x) {} 1066 #endif 1067 void Canonicalizer::do_MemBar(MemBar* x) {}