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_IR.hpp"
  27 #include "c1/c1_Instruction.hpp"
  28 #include "c1/c1_InstructionPrinter.hpp"
  29 #include "c1/c1_ValueStack.hpp"
  30 #include "ci/ciObjArrayKlass.hpp"
  31 #include "ci/ciTypeArrayKlass.hpp"
  32 #include "ci/ciValueArrayKlass.hpp"
  33 #include "ci/ciValueKlass.hpp"
  34 
  35 
  36 // Implementation of Instruction
  37 
  38 
  39 int Instruction::dominator_depth() {
  40   int result = -1;
  41   if (block()) {
  42     result = block()->dominator_depth();
  43   }
  44   assert(result != -1 || this->as_Local(), "Only locals have dominator depth -1");
  45   return result;
  46 }
  47 
  48 Instruction::Condition Instruction::mirror(Condition cond) {
  49   switch (cond) {
  50     case eql: return eql;
  51     case neq: return neq;
  52     case lss: return gtr;
  53     case leq: return geq;
  54     case gtr: return lss;
  55     case geq: return leq;
  56     case aeq: return beq;
  57     case beq: return aeq;
  58   }
  59   ShouldNotReachHere();
  60   return eql;
  61 }
  62 
  63 
  64 Instruction::Condition Instruction::negate(Condition cond) {
  65   switch (cond) {
  66     case eql: return neq;
  67     case neq: return eql;
  68     case lss: return geq;
  69     case leq: return gtr;
  70     case gtr: return leq;
  71     case geq: return lss;
  72     case aeq: assert(false, "Above equal cannot be negated");
  73     case beq: assert(false, "Below equal cannot be negated");
  74   }
  75   ShouldNotReachHere();
  76   return eql;
  77 }
  78 
  79 void Instruction::update_exception_state(ValueStack* state) {
  80   if (state != NULL && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) {
  81     assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->should_retain_local_variables(), "unexpected state kind");
  82     _exception_state = state;
  83   } else {
  84     _exception_state = NULL;
  85   }
  86 }
  87 
  88 // Prev without need to have BlockBegin
  89 Instruction* Instruction::prev() {
  90   Instruction* p = NULL;
  91   Instruction* q = block();
  92   while (q != this) {
  93     assert(q != NULL, "this is not in the block's instruction list");
  94     p = q; q = q->next();
  95   }
  96   return p;
  97 }
  98 
  99 
 100 void Instruction::state_values_do(ValueVisitor* f) {
 101   if (state_before() != NULL) {
 102     state_before()->values_do(f);
 103   }
 104   if (exception_state() != NULL){
 105     exception_state()->values_do(f);
 106   }
 107 }
 108 
 109 ciType* Instruction::exact_type() const {
 110   ciType* t =  declared_type();
 111   if (t != NULL && t->is_klass()) {
 112     return t->as_klass()->exact_klass();
 113   }
 114   return NULL;
 115 }
 116 
 117 ciKlass* Instruction::as_loaded_klass_or_null() const {
 118   ciType* type = declared_type();
 119   if (type != NULL && type->is_klass()) {
 120     ciKlass* klass = type->as_klass();
 121     if (klass->is_loaded()) {
 122       return klass;
 123     }
 124   }
 125   return NULL;
 126 }
 127 
 128 // FIXME -- this is used by ValueStack::merge_types only. We should remove this function
 129 // and use a better way for handling phi nodes.
 130 bool Instruction::is_flattened_array() const {
 131   if (ValueArrayFlatten) {
 132     ciType* type = declared_type();
 133     if (type != NULL && type->is_value_array_klass()) {
 134       ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
 135       assert(element_klass->is_loaded(), "ciValueKlasses are always loaded");
 136       if (element_klass->flatten_array()) {
 137         return true;
 138       }
 139     }
 140   }
 141 
 142   return false;
 143 }
 144 
 145 bool Instruction::is_loaded_flattened_array() const {
 146   if (ValueArrayFlatten) {
 147     ciType* type = declared_type();
 148     if (type != NULL && type->is_value_array_klass()) {
 149       ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
 150       assert(element_klass->is_loaded(), "ciValueKlasses are always loaded");
 151       if (element_klass->flatten_array()) {
 152         return true;
 153       }
 154     }
 155   }
 156 
 157   return false;
 158 }
 159 
 160 bool Instruction::maybe_flattened_array() {
 161   if (ValueArrayFlatten) {
 162     ciType* type = declared_type();
 163     if (type != NULL) {
 164       if (type->is_value_array_klass()) {
 165         ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
 166         assert(element_klass->is_loaded(), "ciValueKlasses are always loaded");
 167         if (element_klass->flatten_array()) {
 168           return true;
 169         }
 170       } else if (type->is_obj_array_klass()) {
 171         ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
 172         if (!element_klass->is_loaded() || element_klass->is_java_lang_Object() || element_klass->is_interface()) {
 173           // Array covariance:
 174           //    (ValueType[] <: Object[])
 175           //    (ValueType[] <: <any interface>[])
 176           // We will add a runtime check for flat-ness.
 177           return true;
 178         }
 179       } else if (type->is_klass() && type->as_klass()->is_java_lang_Object()) {
 180         // This can happen as a parameter to System.arraycopy()
 181         return true;
 182       }
 183     } else if (as_Phi() != NULL) {
 184       // Type info gets lost during Phi merging, but we might be storing into a
 185       // flattened array, so we should do a runtime check.
 186       return true;
 187     }
 188   }
 189 
 190   return false;
 191 }
 192 
 193 #ifndef PRODUCT
 194 void Instruction::check_state(ValueStack* state) {
 195   if (state != NULL) {
 196     state->verify();
 197   }
 198 }
 199 
 200 
 201 void Instruction::print() {
 202   InstructionPrinter ip;
 203   print(ip);
 204 }
 205 
 206 
 207 void Instruction::print_line() {
 208   InstructionPrinter ip;
 209   ip.print_line(this);
 210 }
 211 
 212 
 213 void Instruction::print(InstructionPrinter& ip) {
 214   ip.print_head();
 215   ip.print_line(this);
 216   tty->cr();
 217 }
 218 #endif // PRODUCT
 219 
 220 
 221 // perform constant and interval tests on index value
 222 bool AccessIndexed::compute_needs_range_check() {
 223   if (length()) {
 224     Constant* clength = length()->as_Constant();
 225     Constant* cindex = index()->as_Constant();
 226     if (clength && cindex) {
 227       IntConstant* l = clength->type()->as_IntConstant();
 228       IntConstant* i = cindex->type()->as_IntConstant();
 229       if (l && i && i->value() < l->value() && i->value() >= 0) {
 230         return false;
 231       }
 232     }
 233   }
 234 
 235   if (!this->check_flag(NeedsRangeCheckFlag)) {
 236     return false;
 237   }
 238 
 239   return true;
 240 }
 241 
 242 
 243 ciType* Constant::exact_type() const {
 244   if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
 245     return type()->as_ObjectType()->exact_type();
 246   }
 247   return NULL;
 248 }
 249 
 250 ciType* LoadIndexed::exact_type() const {
 251   ciType* array_type = array()->exact_type();
 252   if (array_type != NULL) {
 253     assert(array_type->is_array_klass(), "what else?");
 254     ciArrayKlass* ak = (ciArrayKlass*)array_type;
 255 
 256     if (ak->element_type()->is_instance_klass()) {
 257       ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
 258       if (ik->is_loaded() && ik->is_final()) {
 259         return ik;
 260       }
 261     }
 262   }
 263   return Instruction::exact_type();
 264 }
 265 
 266 
 267 ciType* LoadIndexed::declared_type() const {
 268   ciType* array_type = array()->declared_type();
 269   if (array_type == NULL || !array_type->is_loaded()) {
 270     return NULL;
 271   }
 272   assert(array_type->is_array_klass(), "what else?");
 273   ciArrayKlass* ak = (ciArrayKlass*)array_type;
 274   return ak->element_type();
 275 }
 276 
 277 bool StoreIndexed::is_exact_flattened_array_store() const {
 278   if (array()->is_loaded_flattened_array() && value()->as_Constant() == NULL) {
 279     ciKlass* element_klass = array()->declared_type()->as_value_array_klass()->element_klass();
 280     ciKlass* actual_klass = value()->declared_type()->as_klass();
 281     if (element_klass == actual_klass) {
 282       return true;
 283     }
 284   }
 285   return false;
 286 }
 287 
 288 ciType* LoadField::declared_type() const {
 289   return field()->type();
 290 }
 291 
 292 
 293 ciType* NewTypeArray::exact_type() const {
 294   return ciTypeArrayKlass::make(elt_type());
 295 }
 296 
 297 ciType* NewObjectArray::exact_type() const {
 298   ciKlass* element_klass = klass();
 299   if (element_klass->is_valuetype()) {
 300     return ciValueArrayKlass::make(element_klass);
 301   } else {
 302     return ciObjArrayKlass::make(element_klass);
 303   }
 304 }
 305 
 306 ciType* NewMultiArray::exact_type() const {
 307   return _klass;
 308 }
 309 
 310 ciType* NewArray::declared_type() const {
 311   return exact_type();
 312 }
 313 
 314 ciType* NewInstance::exact_type() const {
 315   return klass();
 316 }
 317 
 318 ciType* NewInstance::declared_type() const {
 319   return exact_type();
 320 }
 321 
 322 Value NewValueTypeInstance::depends_on() {
 323   if (_depends_on != this) {
 324     if (_depends_on->as_NewValueTypeInstance() != NULL) {
 325       return _depends_on->as_NewValueTypeInstance()->depends_on();
 326     }
 327   }
 328   return _depends_on;
 329 }
 330 
 331 ciType* NewValueTypeInstance::exact_type() const {
 332   return klass();
 333 }
 334 
 335 ciType* NewValueTypeInstance::declared_type() const {
 336   return exact_type();
 337 }
 338 
 339 ciType* CheckCast::declared_type() const {
 340   return klass();
 341 }
 342 
 343 // Implementation of ArithmeticOp
 344 
 345 bool ArithmeticOp::is_commutative() const {
 346   switch (op()) {
 347     case Bytecodes::_iadd: // fall through
 348     case Bytecodes::_ladd: // fall through
 349     case Bytecodes::_fadd: // fall through
 350     case Bytecodes::_dadd: // fall through
 351     case Bytecodes::_imul: // fall through
 352     case Bytecodes::_lmul: // fall through
 353     case Bytecodes::_fmul: // fall through
 354     case Bytecodes::_dmul: return true;
 355     default              : return false;
 356   }
 357 }
 358 
 359 
 360 bool ArithmeticOp::can_trap() const {
 361   switch (op()) {
 362     case Bytecodes::_idiv: // fall through
 363     case Bytecodes::_ldiv: // fall through
 364     case Bytecodes::_irem: // fall through
 365     case Bytecodes::_lrem: return true;
 366     default              : return false;
 367   }
 368 }
 369 
 370 
 371 // Implementation of LogicOp
 372 
 373 bool LogicOp::is_commutative() const {
 374 #ifdef ASSERT
 375   switch (op()) {
 376     case Bytecodes::_iand: // fall through
 377     case Bytecodes::_land: // fall through
 378     case Bytecodes::_ior : // fall through
 379     case Bytecodes::_lor : // fall through
 380     case Bytecodes::_ixor: // fall through
 381     case Bytecodes::_lxor: break;
 382     default              : ShouldNotReachHere(); break;
 383   }
 384 #endif
 385   // all LogicOps are commutative
 386   return true;
 387 }
 388 
 389 
 390 // Implementation of IfOp
 391 
 392 bool IfOp::is_commutative() const {
 393   return cond() == eql || cond() == neq;
 394 }
 395 
 396 
 397 // Implementation of StateSplit
 398 
 399 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
 400   NOT_PRODUCT(bool assigned = false;)
 401   for (int i = 0; i < list.length(); i++) {
 402     BlockBegin** b = list.adr_at(i);
 403     if (*b == old_block) {
 404       *b = new_block;
 405       NOT_PRODUCT(assigned = true;)
 406     }
 407   }
 408   assert(assigned == true, "should have assigned at least once");
 409 }
 410 
 411 
 412 IRScope* StateSplit::scope() const {
 413   return _state->scope();
 414 }
 415 
 416 
 417 void StateSplit::state_values_do(ValueVisitor* f) {
 418   Instruction::state_values_do(f);
 419   if (state() != NULL) state()->values_do(f);
 420 }
 421 
 422 
 423 void BlockBegin::state_values_do(ValueVisitor* f) {
 424   StateSplit::state_values_do(f);
 425 
 426   if (is_set(BlockBegin::exception_entry_flag)) {
 427     for (int i = 0; i < number_of_exception_states(); i++) {
 428       exception_state_at(i)->values_do(f);
 429     }
 430   }
 431 }
 432 
 433 
 434 // Implementation of Invoke
 435 
 436 
 437 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
 438                int vtable_index, ciMethod* target, ValueStack* state_before, bool never_null)
 439   : StateSplit(result_type, state_before)
 440   , _code(code)
 441   , _recv(recv)
 442   , _args(args)
 443   , _vtable_index(vtable_index)
 444   , _target(target)
 445 {
 446   set_flag(TargetIsLoadedFlag,   target->is_loaded());
 447   set_flag(TargetIsFinalFlag,    target_is_loaded() && target->is_final_method());
 448   set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
 449   set_never_null(never_null);
 450 
 451   assert(args != NULL, "args must exist");
 452 #ifdef ASSERT
 453   AssertValues assert_value;
 454   values_do(&assert_value);
 455 #endif
 456 
 457   // provide an initial guess of signature size.
 458   _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
 459   if (has_receiver()) {
 460     _signature->append(as_BasicType(receiver()->type()));
 461   }
 462   for (int i = 0; i < number_of_arguments(); i++) {
 463     ValueType* t = argument_at(i)->type();
 464     BasicType bt = as_BasicType(t);
 465     _signature->append(bt);
 466   }
 467 }
 468 
 469 
 470 void Invoke::state_values_do(ValueVisitor* f) {
 471   StateSplit::state_values_do(f);
 472   if (state_before() != NULL) state_before()->values_do(f);
 473   if (state()        != NULL) state()->values_do(f);
 474 }
 475 
 476 ciType* Invoke::declared_type() const {
 477   ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
 478   ciType *t = declared_signature->return_type();
 479   assert(t->basic_type() != T_VOID, "need return value of void method?");
 480   return t;
 481 }
 482 
 483 // Implementation of Contant
 484 intx Constant::hash() const {
 485   if (state_before() == NULL) {
 486     switch (type()->tag()) {
 487     case intTag:
 488       return HASH2(name(), type()->as_IntConstant()->value());
 489     case addressTag:
 490       return HASH2(name(), type()->as_AddressConstant()->value());
 491     case longTag:
 492       {
 493         jlong temp = type()->as_LongConstant()->value();
 494         return HASH3(name(), high(temp), low(temp));
 495       }
 496     case floatTag:
 497       return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
 498     case doubleTag:
 499       {
 500         jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
 501         return HASH3(name(), high(temp), low(temp));
 502       }
 503     case objectTag:
 504       assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
 505       return HASH2(name(), type()->as_ObjectType()->constant_value());
 506     case metaDataTag:
 507       assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
 508       return HASH2(name(), type()->as_MetadataType()->constant_value());
 509     default:
 510       ShouldNotReachHere();
 511     }
 512   }
 513   return 0;
 514 }
 515 
 516 bool Constant::is_equal(Value v) const {
 517   if (v->as_Constant() == NULL) return false;
 518 
 519   switch (type()->tag()) {
 520     case intTag:
 521       {
 522         IntConstant* t1 =    type()->as_IntConstant();
 523         IntConstant* t2 = v->type()->as_IntConstant();
 524         return (t1 != NULL && t2 != NULL &&
 525                 t1->value() == t2->value());
 526       }
 527     case longTag:
 528       {
 529         LongConstant* t1 =    type()->as_LongConstant();
 530         LongConstant* t2 = v->type()->as_LongConstant();
 531         return (t1 != NULL && t2 != NULL &&
 532                 t1->value() == t2->value());
 533       }
 534     case floatTag:
 535       {
 536         FloatConstant* t1 =    type()->as_FloatConstant();
 537         FloatConstant* t2 = v->type()->as_FloatConstant();
 538         return (t1 != NULL && t2 != NULL &&
 539                 jint_cast(t1->value()) == jint_cast(t2->value()));
 540       }
 541     case doubleTag:
 542       {
 543         DoubleConstant* t1 =    type()->as_DoubleConstant();
 544         DoubleConstant* t2 = v->type()->as_DoubleConstant();
 545         return (t1 != NULL && t2 != NULL &&
 546                 jlong_cast(t1->value()) == jlong_cast(t2->value()));
 547       }
 548     case objectTag:
 549       {
 550         ObjectType* t1 =    type()->as_ObjectType();
 551         ObjectType* t2 = v->type()->as_ObjectType();
 552         return (t1 != NULL && t2 != NULL &&
 553                 t1->is_loaded() && t2->is_loaded() &&
 554                 t1->constant_value() == t2->constant_value());
 555       }
 556     case metaDataTag:
 557       {
 558         MetadataType* t1 =    type()->as_MetadataType();
 559         MetadataType* t2 = v->type()->as_MetadataType();
 560         return (t1 != NULL && t2 != NULL &&
 561                 t1->is_loaded() && t2->is_loaded() &&
 562                 t1->constant_value() == t2->constant_value());
 563       }
 564     default:
 565       return false;
 566   }
 567 }
 568 
 569 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
 570   Constant* rc = right->as_Constant();
 571   // other is not a constant
 572   if (rc == NULL) return not_comparable;
 573 
 574   ValueType* lt = type();
 575   ValueType* rt = rc->type();
 576   // different types
 577   if (lt->base() != rt->base()) return not_comparable;
 578   switch (lt->tag()) {
 579   case intTag: {
 580     int x = lt->as_IntConstant()->value();
 581     int y = rt->as_IntConstant()->value();
 582     switch (cond) {
 583     case If::eql: return x == y ? cond_true : cond_false;
 584     case If::neq: return x != y ? cond_true : cond_false;
 585     case If::lss: return x <  y ? cond_true : cond_false;
 586     case If::leq: return x <= y ? cond_true : cond_false;
 587     case If::gtr: return x >  y ? cond_true : cond_false;
 588     case If::geq: return x >= y ? cond_true : cond_false;
 589     default     : break;
 590     }
 591     break;
 592   }
 593   case longTag: {
 594     jlong x = lt->as_LongConstant()->value();
 595     jlong y = rt->as_LongConstant()->value();
 596     switch (cond) {
 597     case If::eql: return x == y ? cond_true : cond_false;
 598     case If::neq: return x != y ? cond_true : cond_false;
 599     case If::lss: return x <  y ? cond_true : cond_false;
 600     case If::leq: return x <= y ? cond_true : cond_false;
 601     case If::gtr: return x >  y ? cond_true : cond_false;
 602     case If::geq: return x >= y ? cond_true : cond_false;
 603     default     : break;
 604     }
 605     break;
 606   }
 607   case objectTag: {
 608     ciObject* xvalue = lt->as_ObjectType()->constant_value();
 609     ciObject* yvalue = rt->as_ObjectType()->constant_value();
 610     assert(xvalue != NULL && yvalue != NULL, "not constants");
 611     if (xvalue->is_loaded() && yvalue->is_loaded()) {
 612       switch (cond) {
 613       case If::eql: return xvalue == yvalue ? cond_true : cond_false;
 614       case If::neq: return xvalue != yvalue ? cond_true : cond_false;
 615       default     : break;
 616       }
 617     }
 618     break;
 619   }
 620   case metaDataTag: {
 621     ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
 622     ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
 623     assert(xvalue != NULL && yvalue != NULL, "not constants");
 624     if (xvalue->is_loaded() && yvalue->is_loaded()) {
 625       switch (cond) {
 626       case If::eql: return xvalue == yvalue ? cond_true : cond_false;
 627       case If::neq: return xvalue != yvalue ? cond_true : cond_false;
 628       default     : break;
 629       }
 630     }
 631     break;
 632   }
 633   default:
 634     break;
 635   }
 636   return not_comparable;
 637 }
 638 
 639 
 640 // Implementation of BlockBegin
 641 
 642 void BlockBegin::set_end(BlockEnd* end) {
 643   assert(end != NULL, "should not reset block end to NULL");
 644   if (end == _end) {
 645     return;
 646   }
 647   clear_end();
 648 
 649   // Set the new end
 650   _end = end;
 651 
 652   _successors.clear();
 653   // Now reset successors list based on BlockEnd
 654   for (int i = 0; i < end->number_of_sux(); i++) {
 655     BlockBegin* sux = end->sux_at(i);
 656     _successors.append(sux);
 657     sux->_predecessors.append(this);
 658   }
 659   _end->set_begin(this);
 660 }
 661 
 662 
 663 void BlockBegin::clear_end() {
 664   // Must make the predecessors/successors match up with the
 665   // BlockEnd's notion.
 666   if (_end != NULL) {
 667     // disconnect from the old end
 668     _end->set_begin(NULL);
 669 
 670     // disconnect this block from it's current successors
 671     for (int i = 0; i < _successors.length(); i++) {
 672       _successors.at(i)->remove_predecessor(this);
 673     }
 674     _end = NULL;
 675   }
 676 }
 677 
 678 
 679 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
 680   // disconnect any edges between from and to
 681 #ifndef PRODUCT
 682   if (PrintIR && Verbose) {
 683     tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
 684   }
 685 #endif
 686   for (int s = 0; s < from->number_of_sux();) {
 687     BlockBegin* sux = from->sux_at(s);
 688     if (sux == to) {
 689       int index = sux->_predecessors.find(from);
 690       if (index >= 0) {
 691         sux->_predecessors.remove_at(index);
 692       }
 693       from->_successors.remove_at(s);
 694     } else {
 695       s++;
 696     }
 697   }
 698 }
 699 
 700 
 701 void BlockBegin::disconnect_from_graph() {
 702   // disconnect this block from all other blocks
 703   for (int p = 0; p < number_of_preds(); p++) {
 704     pred_at(p)->remove_successor(this);
 705   }
 706   for (int s = 0; s < number_of_sux(); s++) {
 707     sux_at(s)->remove_predecessor(this);
 708   }
 709 }
 710 
 711 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
 712   // modify predecessors before substituting successors
 713   for (int i = 0; i < number_of_sux(); i++) {
 714     if (sux_at(i) == old_sux) {
 715       // remove old predecessor before adding new predecessor
 716       // otherwise there is a dead predecessor in the list
 717       new_sux->remove_predecessor(old_sux);
 718       new_sux->add_predecessor(this);
 719     }
 720   }
 721   old_sux->remove_predecessor(this);
 722   end()->substitute_sux(old_sux, new_sux);
 723 }
 724 
 725 
 726 
 727 // In general it is not possible to calculate a value for the field "depth_first_number"
 728 // of the inserted block, without recomputing the values of the other blocks
 729 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
 730 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
 731   int bci = sux->bci();
 732   // critical edge splitting may introduce a goto after a if and array
 733   // bound check elimination may insert a predicate between the if and
 734   // goto. The bci of the goto can't be the one of the if otherwise
 735   // the state and bci are inconsistent and a deoptimization triggered
 736   // by the predicate would lead to incorrect execution/a crash.
 737   BlockBegin* new_sux = new BlockBegin(bci);
 738 
 739   // mark this block (special treatment when block order is computed)
 740   new_sux->set(critical_edge_split_flag);
 741 
 742   // This goto is not a safepoint.
 743   Goto* e = new Goto(sux, false);
 744   new_sux->set_next(e, bci);
 745   new_sux->set_end(e);
 746   // setup states
 747   ValueStack* s = end()->state();
 748   new_sux->set_state(s->copy(s->kind(), bci));
 749   e->set_state(s->copy(s->kind(), bci));
 750   assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
 751   assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
 752   assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
 753 
 754   // link predecessor to new block
 755   end()->substitute_sux(sux, new_sux);
 756 
 757   // The ordering needs to be the same, so remove the link that the
 758   // set_end call above added and substitute the new_sux for this
 759   // block.
 760   sux->remove_predecessor(new_sux);
 761 
 762   // the successor could be the target of a switch so it might have
 763   // multiple copies of this predecessor, so substitute the new_sux
 764   // for the first and delete the rest.
 765   bool assigned = false;
 766   BlockList& list = sux->_predecessors;
 767   for (int i = 0; i < list.length(); i++) {
 768     BlockBegin** b = list.adr_at(i);
 769     if (*b == this) {
 770       if (assigned) {
 771         list.remove_at(i);
 772         // reprocess this index
 773         i--;
 774       } else {
 775         assigned = true;
 776         *b = new_sux;
 777       }
 778       // link the new block back to it's predecessors.
 779       new_sux->add_predecessor(this);
 780     }
 781   }
 782   assert(assigned == true, "should have assigned at least once");
 783   return new_sux;
 784 }
 785 
 786 
 787 void BlockBegin::remove_successor(BlockBegin* pred) {
 788   int idx;
 789   while ((idx = _successors.find(pred)) >= 0) {
 790     _successors.remove_at(idx);
 791   }
 792 }
 793 
 794 
 795 void BlockBegin::add_predecessor(BlockBegin* pred) {
 796   _predecessors.append(pred);
 797 }
 798 
 799 
 800 void BlockBegin::remove_predecessor(BlockBegin* pred) {
 801   int idx;
 802   while ((idx = _predecessors.find(pred)) >= 0) {
 803     _predecessors.remove_at(idx);
 804   }
 805 }
 806 
 807 
 808 void BlockBegin::add_exception_handler(BlockBegin* b) {
 809   assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
 810   // add only if not in the list already
 811   if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
 812 }
 813 
 814 int BlockBegin::add_exception_state(ValueStack* state) {
 815   assert(is_set(exception_entry_flag), "only for xhandlers");
 816   if (_exception_states == NULL) {
 817     _exception_states = new ValueStackStack(4);
 818   }
 819   _exception_states->append(state);
 820   return _exception_states->length() - 1;
 821 }
 822 
 823 
 824 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
 825   if (!mark.at(block_id())) {
 826     mark.at_put(block_id(), true);
 827     closure->block_do(this);
 828     BlockEnd* e = end(); // must do this after block_do because block_do may change it!
 829     { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
 830     { for (int i = e->number_of_sux            () - 1; i >= 0; i--) e->sux_at           (i)->iterate_preorder(mark, closure); }
 831   }
 832 }
 833 
 834 
 835 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
 836   if (!mark.at(block_id())) {
 837     mark.at_put(block_id(), true);
 838     BlockEnd* e = end();
 839     { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
 840     { for (int i = e->number_of_sux            () - 1; i >= 0; i--) e->sux_at           (i)->iterate_postorder(mark, closure); }
 841     closure->block_do(this);
 842   }
 843 }
 844 
 845 
 846 void BlockBegin::iterate_preorder(BlockClosure* closure) {
 847   int mark_len = number_of_blocks();
 848   boolArray mark(mark_len, mark_len, false);
 849   iterate_preorder(mark, closure);
 850 }
 851 
 852 
 853 void BlockBegin::iterate_postorder(BlockClosure* closure) {
 854   int mark_len = number_of_blocks();
 855   boolArray mark(mark_len, mark_len, false);
 856   iterate_postorder(mark, closure);
 857 }
 858 
 859 
 860 void BlockBegin::block_values_do(ValueVisitor* f) {
 861   for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
 862 }
 863 
 864 
 865 #ifndef PRODUCT
 866    #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
 867 #else
 868    #define TRACE_PHI(coce)
 869 #endif
 870 
 871 
 872 bool BlockBegin::try_merge(ValueStack* new_state) {
 873   TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
 874 
 875   // local variables used for state iteration
 876   int index;
 877   Value new_value, existing_value;
 878 
 879   ValueStack* existing_state = state();
 880   if (existing_state == NULL) {
 881     TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
 882 
 883     if (is_set(BlockBegin::was_visited_flag)) {
 884       // this actually happens for complicated jsr/ret structures
 885       return false; // BAILOUT in caller
 886     }
 887 
 888     // copy state because it is altered
 889     new_state = new_state->copy(ValueStack::BlockBeginState, bci());
 890 
 891     // Use method liveness to invalidate dead locals
 892     MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
 893     if (liveness.is_valid()) {
 894       assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
 895 
 896       for_each_local_value(new_state, index, new_value) {
 897         if (!liveness.at(index) || new_value->type()->is_illegal()) {
 898           new_state->invalidate_local(index);
 899           TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
 900         }
 901       }
 902     }
 903 
 904     if (is_set(BlockBegin::parser_loop_header_flag)) {
 905       TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
 906 
 907       for_each_stack_value(new_state, index, new_value) {
 908         new_state->setup_phi_for_stack(this, index, NULL, new_value);
 909         TRACE_PHI(tty->print_cr("creating phi-function %c%d for stack %d", new_state->stack_at(index)->type()->tchar(), new_state->stack_at(index)->id(), index));
 910       }
 911 
 912       BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
 913 
 914       for_each_local_value(new_state, index, new_value) {
 915         bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
 916         if (requires_phi || !SelectivePhiFunctions) {
 917           new_state->setup_phi_for_local(this, index, NULL, new_value);
 918           TRACE_PHI(tty->print_cr("creating phi-function %c%d for local %d", new_state->local_at(index)->type()->tchar(), new_state->local_at(index)->id(), index));
 919         }
 920       }
 921     }
 922 
 923     // initialize state of block
 924     set_state(new_state);
 925 
 926   } else if (existing_state->is_same(new_state)) {
 927     TRACE_PHI(tty->print_cr("exisiting state found"));
 928 
 929     assert(existing_state->scope() == new_state->scope(), "not matching");
 930     assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
 931     assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
 932 
 933     if (is_set(BlockBegin::was_visited_flag)) {
 934       TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
 935 
 936       if (!is_set(BlockBegin::parser_loop_header_flag)) {
 937         // this actually happens for complicated jsr/ret structures
 938         return false; // BAILOUT in caller
 939       }
 940 
 941       for_each_local_value(existing_state, index, existing_value) {
 942         Value new_value = new_state->local_at(index);
 943         if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
 944           Phi* existing_phi = existing_value->as_Phi();
 945           if (existing_phi == NULL) {
 946             return false; // BAILOUT in caller
 947           }
 948           // Invalidate the phi function here. This case is very rare except for
 949           // JVMTI capability "can_access_local_variables".
 950           // In really rare cases we will bail out in LIRGenerator::move_to_phi.
 951           existing_phi->make_illegal();
 952           existing_state->invalidate_local(index);
 953           TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
 954         }
 955       }
 956 
 957 #ifdef ASSERT
 958       // check that all necessary phi functions are present
 959       for_each_stack_value(existing_state, index, existing_value) {
 960         assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
 961       }
 962       for_each_local_value(existing_state, index, existing_value) {
 963         assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
 964       }
 965 #endif
 966 
 967     } else {
 968       TRACE_PHI(tty->print_cr("creating phi functions on demand"));
 969 
 970       // create necessary phi functions for stack
 971       for_each_stack_value(existing_state, index, existing_value) {
 972         Value new_value = new_state->stack_at(index);
 973         Phi* existing_phi = existing_value->as_Phi();
 974 
 975         if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
 976           existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
 977           TRACE_PHI(tty->print_cr("creating phi-function %c%d for stack %d", existing_state->stack_at(index)->type()->tchar(), existing_state->stack_at(index)->id(), index));
 978         }
 979       }
 980 
 981       // create necessary phi functions for locals
 982       for_each_local_value(existing_state, index, existing_value) {
 983         Value new_value = new_state->local_at(index);
 984         Phi* existing_phi = existing_value->as_Phi();
 985 
 986         if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
 987           existing_state->invalidate_local(index);
 988           TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
 989         } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
 990           existing_state->setup_phi_for_local(this, index, existing_value, new_value);
 991           TRACE_PHI(tty->print_cr("creating phi-function %c%d for local %d", existing_state->local_at(index)->type()->tchar(), existing_state->local_at(index)->id(), index));
 992         }
 993       }
 994     }
 995 
 996     assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
 997 
 998   } else {
 999     assert(false, "stack or locks not matching (invalid bytecodes)");
1000     return false;
1001   }
1002 
1003   TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
1004 
1005   return true;
1006 }
1007 
1008 
1009 #ifndef PRODUCT
1010 void BlockBegin::print_block() {
1011   InstructionPrinter ip;
1012   print_block(ip, false);
1013 }
1014 
1015 
1016 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
1017   ip.print_instr(this); tty->cr();
1018   ip.print_stack(this->state()); tty->cr();
1019   ip.print_inline_level(this);
1020   ip.print_head();
1021   for (Instruction* n = next(); n != NULL; n = n->next()) {
1022     if (!live_only || n->is_pinned() || n->use_count() > 0) {
1023       ip.print_line(n);
1024     }
1025   }
1026   tty->cr();
1027 }
1028 #endif // PRODUCT
1029 
1030 
1031 // Implementation of BlockList
1032 
1033 void BlockList::iterate_forward (BlockClosure* closure) {
1034   const int l = length();
1035   for (int i = 0; i < l; i++) closure->block_do(at(i));
1036 }
1037 
1038 
1039 void BlockList::iterate_backward(BlockClosure* closure) {
1040   for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1041 }
1042 
1043 
1044 void BlockList::blocks_do(void f(BlockBegin*)) {
1045   for (int i = length() - 1; i >= 0; i--) f(at(i));
1046 }
1047 
1048 
1049 void BlockList::values_do(ValueVisitor* f) {
1050   for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1051 }
1052 
1053 
1054 #ifndef PRODUCT
1055 void BlockList::print(bool cfg_only, bool live_only) {
1056   InstructionPrinter ip;
1057   for (int i = 0; i < length(); i++) {
1058     BlockBegin* block = at(i);
1059     if (cfg_only) {
1060       ip.print_instr(block); tty->cr();
1061     } else {
1062       block->print_block(ip, live_only);
1063     }
1064   }
1065 }
1066 #endif // PRODUCT
1067 
1068 
1069 // Implementation of BlockEnd
1070 
1071 void BlockEnd::set_begin(BlockBegin* begin) {
1072   BlockList* sux = NULL;
1073   if (begin != NULL) {
1074     sux = begin->successors();
1075   } else if (this->begin() != NULL) {
1076     // copy our sux list
1077     BlockList* sux = new BlockList(this->begin()->number_of_sux());
1078     for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1079       sux->append(this->begin()->sux_at(i));
1080     }
1081   }
1082   _sux = sux;
1083 }
1084 
1085 
1086 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1087   substitute(*_sux, old_sux, new_sux);
1088 }
1089 
1090 
1091 // Implementation of Phi
1092 
1093 // Normal phi functions take their operands from the last instruction of the
1094 // predecessor. Special handling is needed for xhanlder entries because there
1095 // the state of arbitrary instructions are needed.
1096 
1097 Value Phi::operand_at(int i) const {
1098   ValueStack* state;
1099   if (_block->is_set(BlockBegin::exception_entry_flag)) {
1100     state = _block->exception_state_at(i);
1101   } else {
1102     state = _block->pred_at(i)->end()->state();
1103   }
1104   assert(state != NULL, "");
1105 
1106   if (is_local()) {
1107     return state->local_at(local_index());
1108   } else {
1109     return state->stack_at(stack_index());
1110   }
1111 }
1112 
1113 
1114 int Phi::operand_count() const {
1115   if (_block->is_set(BlockBegin::exception_entry_flag)) {
1116     return _block->number_of_exception_states();
1117   } else {
1118     return _block->number_of_preds();
1119   }
1120 }
1121 
1122 #ifdef ASSERT
1123 // Constructor of Assert
1124 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1125   , _x(x)
1126   , _cond(cond)
1127   , _y(y)
1128 {
1129   set_flag(UnorderedIsTrueFlag, unordered_is_true);
1130   assert(x->type()->tag() == y->type()->tag(), "types must match");
1131   pin();
1132 
1133   stringStream strStream;
1134   Compilation::current()->method()->print_name(&strStream);
1135 
1136   stringStream strStream1;
1137   InstructionPrinter ip1(1, &strStream1);
1138   ip1.print_instr(x);
1139 
1140   stringStream strStream2;
1141   InstructionPrinter ip2(1, &strStream2);
1142   ip2.print_instr(y);
1143 
1144   stringStream ss;
1145   ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1146 
1147   _message = ss.as_string();
1148 }
1149 #endif
1150 
1151 void RangeCheckPredicate::check_state() {
1152   assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1153 }
1154 
1155 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1156   if (state() != NULL) state()->values_do(f);
1157 }
--- EOF ---