1 /*
   2  * Copyright (c) 1997, 2025, 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 "compiler/compileLog.hpp"
  26 #include "ci/bcEscapeAnalyzer.hpp"
  27 #include "compiler/oopMap.hpp"
  28 #include "gc/shared/barrierSet.hpp"
  29 #include "gc/shared/c2/barrierSetC2.hpp"
  30 #include "interpreter/interpreter.hpp"
  31 #include "opto/callGenerator.hpp"
  32 #include "opto/callnode.hpp"
  33 #include "opto/castnode.hpp"
  34 #include "opto/convertnode.hpp"
  35 #include "opto/escape.hpp"
  36 #include "opto/locknode.hpp"
  37 #include "opto/machnode.hpp"
  38 #include "opto/matcher.hpp"
  39 #include "opto/parse.hpp"
  40 #include "opto/regalloc.hpp"
  41 #include "opto/regmask.hpp"
  42 #include "opto/rootnode.hpp"
  43 #include "opto/runtime.hpp"
  44 #include "runtime/sharedRuntime.hpp"
  45 #include "utilities/powerOfTwo.hpp"
  46 #include "code/vmreg.hpp"
  47 
  48 // Portions of code courtesy of Clifford Click
  49 
  50 // Optimization - Graph Style
  51 
  52 //=============================================================================
  53 uint StartNode::size_of() const { return sizeof(*this); }
  54 bool StartNode::cmp( const Node &n ) const
  55 { return _domain == ((StartNode&)n)._domain; }
  56 const Type *StartNode::bottom_type() const { return _domain; }
  57 const Type* StartNode::Value(PhaseGVN* phase) const { return _domain; }
  58 #ifndef PRODUCT
  59 void StartNode::dump_spec(outputStream *st) const { st->print(" #"); _domain->dump_on(st);}
  60 void StartNode::dump_compact_spec(outputStream *st) const { /* empty */ }
  61 #endif
  62 
  63 //------------------------------Ideal------------------------------------------
  64 Node *StartNode::Ideal(PhaseGVN *phase, bool can_reshape){
  65   return remove_dead_region(phase, can_reshape) ? this : nullptr;
  66 }
  67 
  68 //------------------------------calling_convention-----------------------------
  69 void StartNode::calling_convention(BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt) const {
  70   SharedRuntime::java_calling_convention(sig_bt, parm_regs, argcnt);
  71 }
  72 
  73 //------------------------------Registers--------------------------------------
  74 const RegMask &StartNode::in_RegMask(uint) const {
  75   return RegMask::Empty;
  76 }
  77 
  78 //------------------------------match------------------------------------------
  79 // Construct projections for incoming parameters, and their RegMask info
  80 Node *StartNode::match( const ProjNode *proj, const Matcher *match ) {
  81   switch (proj->_con) {
  82   case TypeFunc::Control:
  83   case TypeFunc::I_O:
  84   case TypeFunc::Memory:
  85     return new MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
  86   case TypeFunc::FramePtr:
  87     return new MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);
  88   case TypeFunc::ReturnAdr:
  89     return new MachProjNode(this,proj->_con,match->_return_addr_mask,Op_RegP);
  90   case TypeFunc::Parms:
  91   default: {
  92       uint parm_num = proj->_con - TypeFunc::Parms;
  93       const Type *t = _domain->field_at(proj->_con);
  94       if (t->base() == Type::Half)  // 2nd half of Longs and Doubles
  95         return new ConNode(Type::TOP);
  96       uint ideal_reg = t->ideal_reg();
  97       RegMask &rm = match->_calling_convention_mask[parm_num];
  98       return new MachProjNode(this,proj->_con,rm,ideal_reg);
  99     }
 100   }
 101   return nullptr;
 102 }
 103 
 104 //------------------------------StartOSRNode----------------------------------
 105 // The method start node for an on stack replacement adapter
 106 
 107 //------------------------------osr_domain-----------------------------
 108 const TypeTuple *StartOSRNode::osr_domain() {
 109   const Type **fields = TypeTuple::fields(2);
 110   fields[TypeFunc::Parms+0] = TypeRawPtr::BOTTOM;  // address of osr buffer
 111 
 112   return TypeTuple::make(TypeFunc::Parms+1, fields);
 113 }
 114 
 115 //=============================================================================
 116 const char * const ParmNode::names[TypeFunc::Parms+1] = {
 117   "Control", "I_O", "Memory", "FramePtr", "ReturnAdr", "Parms"
 118 };
 119 
 120 #ifndef PRODUCT
 121 void ParmNode::dump_spec(outputStream *st) const {
 122   if( _con < TypeFunc::Parms ) {
 123     st->print("%s", names[_con]);
 124   } else {
 125     st->print("Parm%d: ",_con-TypeFunc::Parms);
 126     // Verbose and WizardMode dump bottom_type for all nodes
 127     if( !Verbose && !WizardMode )   bottom_type()->dump_on(st);
 128   }
 129 }
 130 
 131 void ParmNode::dump_compact_spec(outputStream *st) const {
 132   if (_con < TypeFunc::Parms) {
 133     st->print("%s", names[_con]);
 134   } else {
 135     st->print("%d:", _con-TypeFunc::Parms);
 136     // unconditionally dump bottom_type
 137     bottom_type()->dump_on(st);
 138   }
 139 }
 140 #endif
 141 
 142 uint ParmNode::ideal_reg() const {
 143   switch( _con ) {
 144   case TypeFunc::Control  : // fall through
 145   case TypeFunc::I_O      : // fall through
 146   case TypeFunc::Memory   : return 0;
 147   case TypeFunc::FramePtr : // fall through
 148   case TypeFunc::ReturnAdr: return Op_RegP;
 149   default                 : assert( _con > TypeFunc::Parms, "" );
 150     // fall through
 151   case TypeFunc::Parms    : {
 152     // Type of argument being passed
 153     const Type *t = in(0)->as_Start()->_domain->field_at(_con);
 154     return t->ideal_reg();
 155   }
 156   }
 157   ShouldNotReachHere();
 158   return 0;
 159 }
 160 
 161 //=============================================================================
 162 ReturnNode::ReturnNode(uint edges, Node *cntrl, Node *i_o, Node *memory, Node *frameptr, Node *retadr ) : Node(edges) {
 163   init_req(TypeFunc::Control,cntrl);
 164   init_req(TypeFunc::I_O,i_o);
 165   init_req(TypeFunc::Memory,memory);
 166   init_req(TypeFunc::FramePtr,frameptr);
 167   init_req(TypeFunc::ReturnAdr,retadr);
 168 }
 169 
 170 Node *ReturnNode::Ideal(PhaseGVN *phase, bool can_reshape){
 171   return remove_dead_region(phase, can_reshape) ? this : nullptr;
 172 }
 173 
 174 const Type* ReturnNode::Value(PhaseGVN* phase) const {
 175   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
 176     ? Type::TOP
 177     : Type::BOTTOM;
 178 }
 179 
 180 // Do we Match on this edge index or not?  No edges on return nodes
 181 uint ReturnNode::match_edge(uint idx) const {
 182   return 0;
 183 }
 184 
 185 
 186 #ifndef PRODUCT
 187 void ReturnNode::dump_req(outputStream *st, DumpConfig* dc) const {
 188   // Dump the required inputs, after printing "returns"
 189   uint i;                       // Exit value of loop
 190   for (i = 0; i < req(); i++) {    // For all required inputs
 191     if (i == TypeFunc::Parms) st->print("returns ");
 192     Node* p = in(i);
 193     if (p != nullptr) {
 194       p->dump_idx(false, st, dc);
 195       st->print(" ");
 196     } else {
 197       st->print("_ ");
 198     }
 199   }
 200 }
 201 #endif
 202 
 203 //=============================================================================
 204 RethrowNode::RethrowNode(
 205   Node* cntrl,
 206   Node* i_o,
 207   Node* memory,
 208   Node* frameptr,
 209   Node* ret_adr,
 210   Node* exception
 211 ) : Node(TypeFunc::Parms + 1) {
 212   init_req(TypeFunc::Control  , cntrl    );
 213   init_req(TypeFunc::I_O      , i_o      );
 214   init_req(TypeFunc::Memory   , memory   );
 215   init_req(TypeFunc::FramePtr , frameptr );
 216   init_req(TypeFunc::ReturnAdr, ret_adr);
 217   init_req(TypeFunc::Parms    , exception);
 218 }
 219 
 220 Node *RethrowNode::Ideal(PhaseGVN *phase, bool can_reshape){
 221   return remove_dead_region(phase, can_reshape) ? this : nullptr;
 222 }
 223 
 224 const Type* RethrowNode::Value(PhaseGVN* phase) const {
 225   return (phase->type(in(TypeFunc::Control)) == Type::TOP)
 226     ? Type::TOP
 227     : Type::BOTTOM;
 228 }
 229 
 230 uint RethrowNode::match_edge(uint idx) const {
 231   return 0;
 232 }
 233 
 234 #ifndef PRODUCT
 235 void RethrowNode::dump_req(outputStream *st, DumpConfig* dc) const {
 236   // Dump the required inputs, after printing "exception"
 237   uint i;                       // Exit value of loop
 238   for (i = 0; i < req(); i++) {    // For all required inputs
 239     if (i == TypeFunc::Parms) st->print("exception ");
 240     Node* p = in(i);
 241     if (p != nullptr) {
 242       p->dump_idx(false, st, dc);
 243       st->print(" ");
 244     } else {
 245       st->print("_ ");
 246     }
 247   }
 248 }
 249 #endif
 250 
 251 //=============================================================================
 252 // Do we Match on this edge index or not?  Match only target address & method
 253 uint TailCallNode::match_edge(uint idx) const {
 254   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 255 }
 256 
 257 //=============================================================================
 258 // Do we Match on this edge index or not?  Match only target address & oop
 259 uint TailJumpNode::match_edge(uint idx) const {
 260   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 261 }
 262 
 263 //=============================================================================
 264 JVMState::JVMState(ciMethod* method, JVMState* caller) :
 265   _method(method) {
 266   assert(method != nullptr, "must be valid call site");
 267   _bci = InvocationEntryBci;
 268   _reexecute = Reexecute_Undefined;
 269   debug_only(_bci = -99);  // random garbage value
 270   debug_only(_map = (SafePointNode*)-1);
 271   _caller = caller;
 272   _depth  = 1 + (caller == nullptr ? 0 : caller->depth());
 273   _locoff = TypeFunc::Parms;
 274   _stkoff = _locoff + _method->max_locals();
 275   _monoff = _stkoff + _method->max_stack();
 276   _scloff = _monoff;
 277   _endoff = _monoff;
 278   _sp = 0;
 279 }
 280 JVMState::JVMState(int stack_size) :
 281   _method(nullptr) {
 282   _bci = InvocationEntryBci;
 283   _reexecute = Reexecute_Undefined;
 284   debug_only(_map = (SafePointNode*)-1);
 285   _caller = nullptr;
 286   _depth  = 1;
 287   _locoff = TypeFunc::Parms;
 288   _stkoff = _locoff;
 289   _monoff = _stkoff + stack_size;
 290   _scloff = _monoff;
 291   _endoff = _monoff;
 292   _sp = 0;
 293 }
 294 
 295 //--------------------------------of_depth-------------------------------------
 296 JVMState* JVMState::of_depth(int d) const {
 297   const JVMState* jvmp = this;
 298   assert(0 < d && (uint)d <= depth(), "oob");
 299   for (int skip = depth() - d; skip > 0; skip--) {
 300     jvmp = jvmp->caller();
 301   }
 302   assert(jvmp->depth() == (uint)d, "found the right one");
 303   return (JVMState*)jvmp;
 304 }
 305 
 306 //-----------------------------same_calls_as-----------------------------------
 307 bool JVMState::same_calls_as(const JVMState* that) const {
 308   if (this == that)                    return true;
 309   if (this->depth() != that->depth())  return false;
 310   const JVMState* p = this;
 311   const JVMState* q = that;
 312   for (;;) {
 313     if (p->_method != q->_method)    return false;
 314     if (p->_method == nullptr)       return true;   // bci is irrelevant
 315     if (p->_bci    != q->_bci)       return false;
 316     if (p->_reexecute != q->_reexecute)  return false;
 317     p = p->caller();
 318     q = q->caller();
 319     if (p == q)                      return true;
 320     assert(p != nullptr && q != nullptr, "depth check ensures we don't run off end");
 321   }
 322 }
 323 
 324 //------------------------------debug_start------------------------------------
 325 uint JVMState::debug_start()  const {
 326   debug_only(JVMState* jvmroot = of_depth(1));
 327   assert(jvmroot->locoff() <= this->locoff(), "youngest JVMState must be last");
 328   return of_depth(1)->locoff();
 329 }
 330 
 331 //-------------------------------debug_end-------------------------------------
 332 uint JVMState::debug_end() const {
 333   debug_only(JVMState* jvmroot = of_depth(1));
 334   assert(jvmroot->endoff() <= this->endoff(), "youngest JVMState must be last");
 335   return endoff();
 336 }
 337 
 338 //------------------------------debug_depth------------------------------------
 339 uint JVMState::debug_depth() const {
 340   uint total = 0;
 341   for (const JVMState* jvmp = this; jvmp != nullptr; jvmp = jvmp->caller()) {
 342     total += jvmp->debug_size();
 343   }
 344   return total;
 345 }
 346 
 347 #ifndef PRODUCT
 348 
 349 //------------------------------format_helper----------------------------------
 350 // Given an allocation (a Chaitin object) and a Node decide if the Node carries
 351 // any defined value or not.  If it does, print out the register or constant.
 352 static void format_helper( PhaseRegAlloc *regalloc, outputStream* st, Node *n, const char *msg, uint i, GrowableArray<SafePointScalarObjectNode*> *scobjs ) {
 353   if (n == nullptr) { st->print(" null"); return; }
 354   if (n->is_SafePointScalarObject()) {
 355     // Scalar replacement.
 356     SafePointScalarObjectNode* spobj = n->as_SafePointScalarObject();
 357     scobjs->append_if_missing(spobj);
 358     int sco_n = scobjs->find(spobj);
 359     assert(sco_n >= 0, "");
 360     st->print(" %s%d]=#ScObj" INT32_FORMAT, msg, i, sco_n);
 361     return;
 362   }
 363   if (regalloc->node_regs_max_index() > 0 &&
 364       OptoReg::is_valid(regalloc->get_reg_first(n))) { // Check for undefined
 365     char buf[50];
 366     regalloc->dump_register(n,buf,sizeof(buf));
 367     st->print(" %s%d]=%s",msg,i,buf);
 368   } else {                      // No register, but might be constant
 369     const Type *t = n->bottom_type();
 370     switch (t->base()) {
 371     case Type::Int:
 372       st->print(" %s%d]=#" INT32_FORMAT,msg,i,t->is_int()->get_con());
 373       break;
 374     case Type::AnyPtr:
 375       assert( t == TypePtr::NULL_PTR || n->in_dump(), "" );
 376       st->print(" %s%d]=#null",msg,i);
 377       break;
 378     case Type::AryPtr:
 379     case Type::InstPtr:
 380       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->isa_oopptr()->const_oop()));
 381       break;
 382     case Type::KlassPtr:
 383     case Type::AryKlassPtr:
 384     case Type::InstKlassPtr:
 385       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_klassptr()->exact_klass()));
 386       break;
 387     case Type::MetadataPtr:
 388       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_metadataptr()->metadata()));
 389       break;
 390     case Type::NarrowOop:
 391       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_oopptr()->const_oop()));
 392       break;
 393     case Type::RawPtr:
 394       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,p2i(t->is_rawptr()));
 395       break;
 396     case Type::DoubleCon:
 397       st->print(" %s%d]=#%fD",msg,i,t->is_double_constant()->_d);
 398       break;
 399     case Type::FloatCon:
 400       st->print(" %s%d]=#%fF",msg,i,t->is_float_constant()->_f);
 401       break;
 402     case Type::Long:
 403       st->print(" %s%d]=#" INT64_FORMAT,msg,i,(int64_t)(t->is_long()->get_con()));
 404       break;
 405     case Type::Half:
 406     case Type::Top:
 407       st->print(" %s%d]=_",msg,i);
 408       break;
 409     default: ShouldNotReachHere();
 410     }
 411   }
 412 }
 413 
 414 //---------------------print_method_with_lineno--------------------------------
 415 void JVMState::print_method_with_lineno(outputStream* st, bool show_name) const {
 416   if (show_name) _method->print_short_name(st);
 417 
 418   int lineno = _method->line_number_from_bci(_bci);
 419   if (lineno != -1) {
 420     st->print(" @ bci:%d (line %d)", _bci, lineno);
 421   } else {
 422     st->print(" @ bci:%d", _bci);
 423   }
 424 }
 425 
 426 //------------------------------format-----------------------------------------
 427 void JVMState::format(PhaseRegAlloc *regalloc, const Node *n, outputStream* st) const {
 428   st->print("        #");
 429   if (_method) {
 430     print_method_with_lineno(st, true);
 431   } else {
 432     st->print_cr(" runtime stub ");
 433     return;
 434   }
 435   if (n->is_MachSafePoint()) {
 436     GrowableArray<SafePointScalarObjectNode*> scobjs;
 437     MachSafePointNode *mcall = n->as_MachSafePoint();
 438     uint i;
 439     // Print locals
 440     for (i = 0; i < (uint)loc_size(); i++)
 441       format_helper(regalloc, st, mcall->local(this, i), "L[", i, &scobjs);
 442     // Print stack
 443     for (i = 0; i < (uint)stk_size(); i++) {
 444       if ((uint)(_stkoff + i) >= mcall->len())
 445         st->print(" oob ");
 446       else
 447        format_helper(regalloc, st, mcall->stack(this, i), "STK[", i, &scobjs);
 448     }
 449     for (i = 0; (int)i < nof_monitors(); i++) {
 450       Node *box = mcall->monitor_box(this, i);
 451       Node *obj = mcall->monitor_obj(this, i);
 452       if (regalloc->node_regs_max_index() > 0 &&
 453           OptoReg::is_valid(regalloc->get_reg_first(box))) {
 454         box = BoxLockNode::box_node(box);
 455         format_helper(regalloc, st, box, "MON-BOX[", i, &scobjs);
 456       } else {
 457         OptoReg::Name box_reg = BoxLockNode::reg(box);
 458         st->print(" MON-BOX%d=%s+%d",
 459                    i,
 460                    OptoReg::regname(OptoReg::c_frame_pointer),
 461                    regalloc->reg2offset(box_reg));
 462       }
 463       const char* obj_msg = "MON-OBJ[";
 464       if (EliminateLocks) {
 465         if (BoxLockNode::box_node(box)->is_eliminated())
 466           obj_msg = "MON-OBJ(LOCK ELIMINATED)[";
 467       }
 468       format_helper(regalloc, st, obj, obj_msg, i, &scobjs);
 469     }
 470 
 471     for (i = 0; i < (uint)scobjs.length(); i++) {
 472       // Scalar replaced objects.
 473       st->cr();
 474       st->print("        # ScObj" INT32_FORMAT " ", i);
 475       SafePointScalarObjectNode* spobj = scobjs.at(i);
 476       ciKlass* cik = spobj->bottom_type()->is_oopptr()->exact_klass();
 477       assert(cik->is_instance_klass() ||
 478              cik->is_array_klass(), "Not supported allocation.");
 479       ciInstanceKlass *iklass = nullptr;
 480       if (cik->is_instance_klass()) {
 481         cik->print_name_on(st);
 482         iklass = cik->as_instance_klass();
 483       } else if (cik->is_type_array_klass()) {
 484         cik->as_array_klass()->base_element_type()->print_name_on(st);
 485         st->print("[%d]", spobj->n_fields());
 486       } else if (cik->is_obj_array_klass()) {
 487         ciKlass* cie = cik->as_obj_array_klass()->base_element_klass();
 488         if (cie->is_instance_klass()) {
 489           cie->print_name_on(st);
 490         } else if (cie->is_type_array_klass()) {
 491           cie->as_array_klass()->base_element_type()->print_name_on(st);
 492         } else {
 493           ShouldNotReachHere();
 494         }
 495         st->print("[%d]", spobj->n_fields());
 496         int ndim = cik->as_array_klass()->dimension() - 1;
 497         while (ndim-- > 0) {
 498           st->print("[]");
 499         }
 500       }
 501       st->print("={");
 502       uint nf = spobj->n_fields();
 503       if (nf > 0) {
 504         uint first_ind = spobj->first_index(mcall->jvms());
 505         Node* fld_node = mcall->in(first_ind);
 506         ciField* cifield;
 507         if (iklass != nullptr) {
 508           st->print(" [");
 509           cifield = iklass->nonstatic_field_at(0);
 510           cifield->print_name_on(st);
 511           format_helper(regalloc, st, fld_node, ":", 0, &scobjs);
 512         } else {
 513           format_helper(regalloc, st, fld_node, "[", 0, &scobjs);
 514         }
 515         for (uint j = 1; j < nf; j++) {
 516           fld_node = mcall->in(first_ind+j);
 517           if (iklass != nullptr) {
 518             st->print(", [");
 519             cifield = iklass->nonstatic_field_at(j);
 520             cifield->print_name_on(st);
 521             format_helper(regalloc, st, fld_node, ":", j, &scobjs);
 522           } else {
 523             format_helper(regalloc, st, fld_node, ", [", j, &scobjs);
 524           }
 525         }
 526       }
 527       st->print(" }");
 528     }
 529   }
 530   st->cr();
 531   if (caller() != nullptr) caller()->format(regalloc, n, st);
 532 }
 533 
 534 
 535 void JVMState::dump_spec(outputStream *st) const {
 536   if (_method != nullptr) {
 537     bool printed = false;
 538     if (!Verbose) {
 539       // The JVMS dumps make really, really long lines.
 540       // Take out the most boring parts, which are the package prefixes.
 541       char buf[500];
 542       stringStream namest(buf, sizeof(buf));
 543       _method->print_short_name(&namest);
 544       if (namest.count() < sizeof(buf)) {
 545         const char* name = namest.base();
 546         if (name[0] == ' ')  ++name;
 547         const char* endcn = strchr(name, ':');  // end of class name
 548         if (endcn == nullptr)  endcn = strchr(name, '(');
 549         if (endcn == nullptr)  endcn = name + strlen(name);
 550         while (endcn > name && endcn[-1] != '.' && endcn[-1] != '/')
 551           --endcn;
 552         st->print(" %s", endcn);
 553         printed = true;
 554       }
 555     }
 556     print_method_with_lineno(st, !printed);
 557     if(_reexecute == Reexecute_True)
 558       st->print(" reexecute");
 559   } else {
 560     st->print(" runtime stub");
 561   }
 562   if (caller() != nullptr)  caller()->dump_spec(st);
 563 }
 564 
 565 
 566 void JVMState::dump_on(outputStream* st) const {
 567   bool print_map = _map && !((uintptr_t)_map & 1) &&
 568                   ((caller() == nullptr) || (caller()->map() != _map));
 569   if (print_map) {
 570     if (_map->len() > _map->req()) {  // _map->has_exceptions()
 571       Node* ex = _map->in(_map->req());  // _map->next_exception()
 572       // skip the first one; it's already being printed
 573       while (ex != nullptr && ex->len() > ex->req()) {
 574         ex = ex->in(ex->req());  // ex->next_exception()
 575         ex->dump(1);
 576       }
 577     }
 578     _map->dump(Verbose ? 2 : 1);
 579   }
 580   if (caller() != nullptr) {
 581     caller()->dump_on(st);
 582   }
 583   st->print("JVMS depth=%d loc=%d stk=%d arg=%d mon=%d scalar=%d end=%d mondepth=%d sp=%d bci=%d reexecute=%s method=",
 584              depth(), locoff(), stkoff(), argoff(), monoff(), scloff(), endoff(), monitor_depth(), sp(), bci(), should_reexecute()?"true":"false");
 585   if (_method == nullptr) {
 586     st->print_cr("(none)");
 587   } else {
 588     _method->print_name(st);
 589     st->cr();
 590     if (bci() >= 0 && bci() < _method->code_size()) {
 591       st->print("    bc: ");
 592       _method->print_codes_on(bci(), bci()+1, st);
 593     }
 594   }
 595 }
 596 
 597 // Extra way to dump a jvms from the debugger,
 598 // to avoid a bug with C++ member function calls.
 599 void dump_jvms(JVMState* jvms) {
 600   jvms->dump();
 601 }
 602 #endif
 603 
 604 //--------------------------clone_shallow--------------------------------------
 605 JVMState* JVMState::clone_shallow(Compile* C) const {
 606   JVMState* n = has_method() ? new (C) JVMState(_method, _caller) : new (C) JVMState(0);
 607   n->set_bci(_bci);
 608   n->_reexecute = _reexecute;
 609   n->set_locoff(_locoff);
 610   n->set_stkoff(_stkoff);
 611   n->set_monoff(_monoff);
 612   n->set_scloff(_scloff);
 613   n->set_endoff(_endoff);
 614   n->set_sp(_sp);
 615   n->set_map(_map);
 616   return n;
 617 }
 618 
 619 //---------------------------clone_deep----------------------------------------
 620 JVMState* JVMState::clone_deep(Compile* C) const {
 621   JVMState* n = clone_shallow(C);
 622   for (JVMState* p = n; p->_caller != nullptr; p = p->_caller) {
 623     p->_caller = p->_caller->clone_shallow(C);
 624   }
 625   assert(n->depth() == depth(), "sanity");
 626   assert(n->debug_depth() == debug_depth(), "sanity");
 627   return n;
 628 }
 629 
 630 /**
 631  * Reset map for all callers
 632  */
 633 void JVMState::set_map_deep(SafePointNode* map) {
 634   for (JVMState* p = this; p != nullptr; p = p->_caller) {
 635     p->set_map(map);
 636   }
 637 }
 638 
 639 // unlike set_map(), this is two-way setting.
 640 void JVMState::bind_map(SafePointNode* map) {
 641   set_map(map);
 642   _map->set_jvms(this);
 643 }
 644 
 645 // Adapt offsets in in-array after adding or removing an edge.
 646 // Prerequisite is that the JVMState is used by only one node.
 647 void JVMState::adapt_position(int delta) {
 648   for (JVMState* jvms = this; jvms != nullptr; jvms = jvms->caller()) {
 649     jvms->set_locoff(jvms->locoff() + delta);
 650     jvms->set_stkoff(jvms->stkoff() + delta);
 651     jvms->set_monoff(jvms->monoff() + delta);
 652     jvms->set_scloff(jvms->scloff() + delta);
 653     jvms->set_endoff(jvms->endoff() + delta);
 654   }
 655 }
 656 
 657 // Mirror the stack size calculation in the deopt code
 658 // How much stack space would we need at this point in the program in
 659 // case of deoptimization?
 660 int JVMState::interpreter_frame_size() const {
 661   const JVMState* jvms = this;
 662   int size = 0;
 663   int callee_parameters = 0;
 664   int callee_locals = 0;
 665   int extra_args = method()->max_stack() - stk_size();
 666 
 667   while (jvms != nullptr) {
 668     int locks = jvms->nof_monitors();
 669     int temps = jvms->stk_size();
 670     bool is_top_frame = (jvms == this);
 671     ciMethod* method = jvms->method();
 672 
 673     int frame_size = BytesPerWord * Interpreter::size_activation(method->max_stack(),
 674                                                                  temps + callee_parameters,
 675                                                                  extra_args,
 676                                                                  locks,
 677                                                                  callee_parameters,
 678                                                                  callee_locals,
 679                                                                  is_top_frame);
 680     size += frame_size;
 681 
 682     callee_parameters = method->size_of_parameters();
 683     callee_locals = method->max_locals();
 684     extra_args = 0;
 685     jvms = jvms->caller();
 686   }
 687   return size + Deoptimization::last_frame_adjust(0, callee_locals) * BytesPerWord;
 688 }
 689 
 690 //=============================================================================
 691 bool CallNode::cmp( const Node &n ) const
 692 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }
 693 #ifndef PRODUCT
 694 void CallNode::dump_req(outputStream *st, DumpConfig* dc) const {
 695   // Dump the required inputs, enclosed in '(' and ')'
 696   uint i;                       // Exit value of loop
 697   for (i = 0; i < req(); i++) {    // For all required inputs
 698     if (i == TypeFunc::Parms) st->print("(");
 699     Node* p = in(i);
 700     if (p != nullptr) {
 701       p->dump_idx(false, st, dc);
 702       st->print(" ");
 703     } else {
 704       st->print("_ ");
 705     }
 706   }
 707   st->print(")");
 708 }
 709 
 710 void CallNode::dump_spec(outputStream *st) const {
 711   st->print(" ");
 712   if (tf() != nullptr)  tf()->dump_on(st);
 713   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);
 714   if (jvms() != nullptr)  jvms()->dump_spec(st);
 715 }
 716 
 717 void AllocateNode::dump_spec(outputStream* st) const {
 718   st->print(" ");
 719   if (tf() != nullptr) {
 720     tf()->dump_on(st);
 721   }
 722   if (_cnt != COUNT_UNKNOWN) {
 723     st->print(" C=%f", _cnt);
 724   }
 725   const Node* const klass_node = in(KlassNode);
 726   if (klass_node != nullptr) {
 727     const TypeKlassPtr* const klass_ptr = klass_node->bottom_type()->isa_klassptr();
 728 
 729     if (klass_ptr != nullptr && klass_ptr->klass_is_exact()) {
 730       st->print(" allocationKlass:");
 731       klass_ptr->exact_klass()->print_name_on(st);
 732     }
 733   }
 734   if (jvms() != nullptr) {
 735     jvms()->dump_spec(st);
 736   }
 737 }
 738 #endif
 739 
 740 const Type *CallNode::bottom_type() const { return tf()->range(); }
 741 const Type* CallNode::Value(PhaseGVN* phase) const {
 742   if (in(0) == nullptr || phase->type(in(0)) == Type::TOP) {
 743     return Type::TOP;
 744   }
 745   return tf()->range();
 746 }
 747 
 748 //------------------------------calling_convention-----------------------------
 749 void CallNode::calling_convention(BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt) const {
 750   // Use the standard compiler calling convention
 751   SharedRuntime::java_calling_convention(sig_bt, parm_regs, argcnt);
 752 }
 753 
 754 
 755 //------------------------------match------------------------------------------
 756 // Construct projections for control, I/O, memory-fields, ..., and
 757 // return result(s) along with their RegMask info
 758 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {
 759   switch (proj->_con) {
 760   case TypeFunc::Control:
 761   case TypeFunc::I_O:
 762   case TypeFunc::Memory:
 763     return new MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
 764 
 765   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns
 766     assert(tf()->range()->field_at(TypeFunc::Parms+1) == Type::HALF, "");
 767     // 2nd half of doubles and longs
 768     return new MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);
 769 
 770   case TypeFunc::Parms: {       // Normal returns
 771     uint ideal_reg = tf()->range()->field_at(TypeFunc::Parms)->ideal_reg();
 772     OptoRegPair regs = Opcode() == Op_CallLeafVector
 773       ? match->vector_return_value(ideal_reg)      // Calls into assembly vector routine
 774       : is_CallRuntime()
 775         ? match->c_return_value(ideal_reg)  // Calls into C runtime
 776         : match->  return_value(ideal_reg); // Calls into compiled Java code
 777     RegMask rm = RegMask(regs.first());
 778 
 779     if (Opcode() == Op_CallLeafVector) {
 780       // If the return is in vector, compute appropriate regmask taking into account the whole range
 781       if(ideal_reg >= Op_VecA && ideal_reg <= Op_VecZ) {
 782         if(OptoReg::is_valid(regs.second())) {
 783           for (OptoReg::Name r = regs.first(); r <= regs.second(); r = OptoReg::add(r, 1)) {
 784             rm.Insert(r);
 785           }
 786         }
 787       }
 788     }
 789 
 790     if( OptoReg::is_valid(regs.second()) )
 791       rm.Insert( regs.second() );
 792     return new MachProjNode(this,proj->_con,rm,ideal_reg);
 793   }
 794 
 795   case TypeFunc::ReturnAdr:
 796   case TypeFunc::FramePtr:
 797   default:
 798     ShouldNotReachHere();
 799   }
 800   return nullptr;
 801 }
 802 
 803 // Do we Match on this edge index or not?  Match no edges
 804 uint CallNode::match_edge(uint idx) const {
 805   return 0;
 806 }
 807 
 808 //
 809 // Determine whether the call could modify the field of the specified
 810 // instance at the specified offset.
 811 //
 812 bool CallNode::may_modify(const TypeOopPtr* t_oop, PhaseValues* phase) {
 813   assert((t_oop != nullptr), "sanity");
 814   if (is_call_to_arraycopystub() && strcmp(_name, "unsafe_arraycopy") != 0) {
 815     const TypeTuple* args = _tf->domain();
 816     Node* dest = nullptr;
 817     // Stubs that can be called once an ArrayCopyNode is expanded have
 818     // different signatures. Look for the second pointer argument,
 819     // that is the destination of the copy.
 820     for (uint i = TypeFunc::Parms, j = 0; i < args->cnt(); i++) {
 821       if (args->field_at(i)->isa_ptr()) {
 822         j++;
 823         if (j == 2) {
 824           dest = in(i);
 825           break;
 826         }
 827       }
 828     }
 829     guarantee(dest != nullptr, "Call had only one ptr in, broken IR!");
 830     if (!dest->is_top() && may_modify_arraycopy_helper(phase->type(dest)->is_oopptr(), t_oop, phase)) {
 831       return true;
 832     }
 833     return false;
 834   }
 835   if (t_oop->is_known_instance()) {
 836     // The instance_id is set only for scalar-replaceable allocations which
 837     // are not passed as arguments according to Escape Analysis.
 838     return false;
 839   }
 840   if (t_oop->is_ptr_to_boxed_value()) {
 841     ciKlass* boxing_klass = t_oop->is_instptr()->instance_klass();
 842     if (is_CallStaticJava() && as_CallStaticJava()->is_boxing_method()) {
 843       // Skip unrelated boxing methods.
 844       Node* proj = proj_out_or_null(TypeFunc::Parms);
 845       if ((proj == nullptr) || (phase->type(proj)->is_instptr()->instance_klass() != boxing_klass)) {
 846         return false;
 847       }
 848     }
 849     if (is_CallJava() && as_CallJava()->method() != nullptr) {
 850       ciMethod* meth = as_CallJava()->method();
 851       if (meth->is_getter()) {
 852         return false;
 853       }
 854       // May modify (by reflection) if an boxing object is passed
 855       // as argument or returned.
 856       Node* proj = returns_pointer() ? proj_out_or_null(TypeFunc::Parms) : nullptr;
 857       if (proj != nullptr) {
 858         const TypeInstPtr* inst_t = phase->type(proj)->isa_instptr();
 859         if ((inst_t != nullptr) && (!inst_t->klass_is_exact() ||
 860                                    (inst_t->instance_klass() == boxing_klass))) {
 861           return true;
 862         }
 863       }
 864       const TypeTuple* d = tf()->domain();
 865       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 866         const TypeInstPtr* inst_t = d->field_at(i)->isa_instptr();
 867         if ((inst_t != nullptr) && (!inst_t->klass_is_exact() ||
 868                                  (inst_t->instance_klass() == boxing_klass))) {
 869           return true;
 870         }
 871       }
 872       return false;
 873     }
 874   }
 875   return true;
 876 }
 877 
 878 // Does this call have a direct reference to n other than debug information?
 879 bool CallNode::has_non_debug_use(Node *n) {
 880   const TypeTuple * d = tf()->domain();
 881   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 882     Node *arg = in(i);
 883     if (arg == n) {
 884       return true;
 885     }
 886   }
 887   return false;
 888 }
 889 
 890 // Returns the unique CheckCastPP of a call
 891 // or 'this' if there are several CheckCastPP or unexpected uses
 892 // or returns null if there is no one.
 893 Node *CallNode::result_cast() {
 894   Node *cast = nullptr;
 895 
 896   Node *p = proj_out_or_null(TypeFunc::Parms);
 897   if (p == nullptr)
 898     return nullptr;
 899 
 900   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {
 901     Node *use = p->fast_out(i);
 902     if (use->is_CheckCastPP()) {
 903       if (cast != nullptr) {
 904         return this;  // more than 1 CheckCastPP
 905       }
 906       cast = use;
 907     } else if (!use->is_Initialize() &&
 908                !use->is_AddP() &&
 909                use->Opcode() != Op_MemBarStoreStore) {
 910       // Expected uses are restricted to a CheckCastPP, an Initialize
 911       // node, a MemBarStoreStore (clone) and AddP nodes. If we
 912       // encounter any other use (a Phi node can be seen in rare
 913       // cases) return this to prevent incorrect optimizations.
 914       return this;
 915     }
 916   }
 917   return cast;
 918 }
 919 
 920 
 921 void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj, bool do_asserts) {
 922   projs->fallthrough_proj      = nullptr;
 923   projs->fallthrough_catchproj = nullptr;
 924   projs->fallthrough_ioproj    = nullptr;
 925   projs->catchall_ioproj       = nullptr;
 926   projs->catchall_catchproj    = nullptr;
 927   projs->fallthrough_memproj   = nullptr;
 928   projs->catchall_memproj      = nullptr;
 929   projs->resproj               = nullptr;
 930   projs->exobj                 = nullptr;
 931 
 932   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 933     ProjNode *pn = fast_out(i)->as_Proj();
 934     if (pn->outcnt() == 0) continue;
 935     switch (pn->_con) {
 936     case TypeFunc::Control:
 937       {
 938         // For Control (fallthrough) and I_O (catch_all_index) we have CatchProj -> Catch -> Proj
 939         projs->fallthrough_proj = pn;
 940         const Node* cn = pn->unique_ctrl_out_or_null();
 941         if (cn != nullptr && cn->is_Catch()) {
 942           ProjNode *cpn = nullptr;
 943           for (DUIterator_Fast kmax, k = cn->fast_outs(kmax); k < kmax; k++) {
 944             cpn = cn->fast_out(k)->as_Proj();
 945             assert(cpn->is_CatchProj(), "must be a CatchProjNode");
 946             if (cpn->_con == CatchProjNode::fall_through_index)
 947               projs->fallthrough_catchproj = cpn;
 948             else {
 949               assert(cpn->_con == CatchProjNode::catch_all_index, "must be correct index.");
 950               projs->catchall_catchproj = cpn;
 951             }
 952           }
 953         }
 954         break;
 955       }
 956     case TypeFunc::I_O:
 957       if (pn->_is_io_use)
 958         projs->catchall_ioproj = pn;
 959       else
 960         projs->fallthrough_ioproj = pn;
 961       for (DUIterator j = pn->outs(); pn->has_out(j); j++) {
 962         Node* e = pn->out(j);
 963         if (e->Opcode() == Op_CreateEx && e->in(0)->is_CatchProj() && e->outcnt() > 0) {
 964           assert(projs->exobj == nullptr, "only one");
 965           projs->exobj = e;
 966         }
 967       }
 968       break;
 969     case TypeFunc::Memory:
 970       if (pn->_is_io_use)
 971         projs->catchall_memproj = pn;
 972       else
 973         projs->fallthrough_memproj = pn;
 974       break;
 975     case TypeFunc::Parms:
 976       projs->resproj = pn;
 977       break;
 978     default:
 979       assert(false, "unexpected projection from allocation node.");
 980     }
 981   }
 982 
 983   // The resproj may not exist because the result could be ignored
 984   // and the exception object may not exist if an exception handler
 985   // swallows the exception but all the other must exist and be found.
 986   assert(projs->fallthrough_proj      != nullptr, "must be found");
 987   do_asserts = do_asserts && !Compile::current()->inlining_incrementally();
 988   assert(!do_asserts || projs->fallthrough_catchproj != nullptr, "must be found");
 989   assert(!do_asserts || projs->fallthrough_memproj   != nullptr, "must be found");
 990   assert(!do_asserts || projs->fallthrough_ioproj    != nullptr, "must be found");
 991   assert(!do_asserts || projs->catchall_catchproj    != nullptr, "must be found");
 992   if (separate_io_proj) {
 993     assert(!do_asserts || projs->catchall_memproj    != nullptr, "must be found");
 994     assert(!do_asserts || projs->catchall_ioproj     != nullptr, "must be found");
 995   }
 996 }
 997 
 998 Node* CallNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 999 #ifdef ASSERT
1000   // Validate attached generator
1001   CallGenerator* cg = generator();
1002   if (cg != nullptr) {
1003     assert((is_CallStaticJava()  && cg->is_mh_late_inline()) ||
1004            (is_CallDynamicJava() && cg->is_virtual_late_inline()), "mismatch");
1005   }
1006 #endif // ASSERT
1007   return SafePointNode::Ideal(phase, can_reshape);
1008 }
1009 
1010 bool CallNode::is_call_to_arraycopystub() const {
1011   if (_name != nullptr && strstr(_name, "arraycopy") != nullptr) {
1012     return true;
1013   }
1014   return false;
1015 }
1016 
1017 //=============================================================================
1018 uint CallJavaNode::size_of() const { return sizeof(*this); }
1019 bool CallJavaNode::cmp( const Node &n ) const {
1020   CallJavaNode &call = (CallJavaNode&)n;
1021   return CallNode::cmp(call) && _method == call._method &&
1022          _override_symbolic_info == call._override_symbolic_info;
1023 }
1024 
1025 void CallJavaNode::copy_call_debug_info(PhaseIterGVN* phase, SafePointNode* sfpt) {
1026   // Copy debug information and adjust JVMState information
1027   uint old_dbg_start = sfpt->is_Call() ? sfpt->as_Call()->tf()->domain()->cnt() : (uint)TypeFunc::Parms+1;
1028   uint new_dbg_start = tf()->domain()->cnt();
1029   int jvms_adj  = new_dbg_start - old_dbg_start;
1030   assert (new_dbg_start == req(), "argument count mismatch");
1031   Compile* C = phase->C;
1032 
1033   // SafePointScalarObject node could be referenced several times in debug info.
1034   // Use Dict to record cloned nodes.
1035   Dict* sosn_map = new Dict(cmpkey,hashkey);
1036   for (uint i = old_dbg_start; i < sfpt->req(); i++) {
1037     Node* old_in = sfpt->in(i);
1038     // Clone old SafePointScalarObjectNodes, adjusting their field contents.
1039     if (old_in != nullptr && old_in->is_SafePointScalarObject()) {
1040       SafePointScalarObjectNode* old_sosn = old_in->as_SafePointScalarObject();
1041       bool new_node;
1042       Node* new_in = old_sosn->clone(sosn_map, new_node);
1043       if (new_node) { // New node?
1044         new_in->set_req(0, C->root()); // reset control edge
1045         new_in = phase->transform(new_in); // Register new node.
1046       }
1047       old_in = new_in;
1048     }
1049     add_req(old_in);
1050   }
1051 
1052   // JVMS may be shared so clone it before we modify it
1053   set_jvms(sfpt->jvms() != nullptr ? sfpt->jvms()->clone_deep(C) : nullptr);
1054   for (JVMState *jvms = this->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1055     jvms->set_map(this);
1056     jvms->set_locoff(jvms->locoff()+jvms_adj);
1057     jvms->set_stkoff(jvms->stkoff()+jvms_adj);
1058     jvms->set_monoff(jvms->monoff()+jvms_adj);
1059     jvms->set_scloff(jvms->scloff()+jvms_adj);
1060     jvms->set_endoff(jvms->endoff()+jvms_adj);
1061   }
1062 }
1063 
1064 #ifdef ASSERT
1065 bool CallJavaNode::validate_symbolic_info() const {
1066   if (method() == nullptr) {
1067     return true; // call into runtime or uncommon trap
1068   }
1069   ciMethod* symbolic_info = jvms()->method()->get_method_at_bci(jvms()->bci());
1070   ciMethod* callee = method();
1071   if (symbolic_info->is_method_handle_intrinsic() && !callee->is_method_handle_intrinsic()) {
1072     assert(override_symbolic_info(), "should be set");
1073   }
1074   assert(ciMethod::is_consistent_info(symbolic_info, callee), "inconsistent info");
1075   return true;
1076 }
1077 #endif
1078 
1079 #ifndef PRODUCT
1080 void CallJavaNode::dump_spec(outputStream* st) const {
1081   if( _method ) _method->print_short_name(st);
1082   CallNode::dump_spec(st);
1083 }
1084 
1085 void CallJavaNode::dump_compact_spec(outputStream* st) const {
1086   if (_method) {
1087     _method->print_short_name(st);
1088   } else {
1089     st->print("<?>");
1090   }
1091 }
1092 #endif
1093 
1094 //=============================================================================
1095 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }
1096 bool CallStaticJavaNode::cmp( const Node &n ) const {
1097   CallStaticJavaNode &call = (CallStaticJavaNode&)n;
1098   return CallJavaNode::cmp(call);
1099 }
1100 
1101 Node* CallStaticJavaNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1102   CallGenerator* cg = generator();
1103   if (can_reshape && cg != nullptr) {
1104     assert(IncrementalInlineMH, "required");
1105     assert(cg->call_node() == this, "mismatch");
1106     assert(cg->is_mh_late_inline(), "not virtual");
1107 
1108     // Check whether this MH handle call becomes a candidate for inlining.
1109     ciMethod* callee = cg->method();
1110     vmIntrinsics::ID iid = callee->intrinsic_id();
1111     if (iid == vmIntrinsics::_invokeBasic) {
1112       if (in(TypeFunc::Parms)->Opcode() == Op_ConP) {
1113         phase->C->prepend_late_inline(cg);
1114         set_generator(nullptr);
1115       }
1116     } else if (iid == vmIntrinsics::_linkToNative) {
1117       // never retry
1118     } else {
1119       assert(callee->has_member_arg(), "wrong type of call?");
1120       if (in(TypeFunc::Parms + callee->arg_size() - 1)->Opcode() == Op_ConP) {
1121         phase->C->prepend_late_inline(cg);
1122         set_generator(nullptr);
1123       }
1124     }
1125   }
1126   return CallNode::Ideal(phase, can_reshape);
1127 }
1128 
1129 //----------------------------is_uncommon_trap----------------------------
1130 // Returns true if this is an uncommon trap.
1131 bool CallStaticJavaNode::is_uncommon_trap() const {
1132   return (_name != nullptr && !strcmp(_name, "uncommon_trap"));
1133 }
1134 
1135 //----------------------------uncommon_trap_request----------------------------
1136 // If this is an uncommon trap, return the request code, else zero.
1137 int CallStaticJavaNode::uncommon_trap_request() const {
1138   return is_uncommon_trap() ? extract_uncommon_trap_request(this) : 0;
1139 }
1140 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {
1141 #ifndef PRODUCT
1142   if (!(call->req() > TypeFunc::Parms &&
1143         call->in(TypeFunc::Parms) != nullptr &&
1144         call->in(TypeFunc::Parms)->is_Con() &&
1145         call->in(TypeFunc::Parms)->bottom_type()->isa_int())) {
1146     assert(in_dump() != 0, "OK if dumping");
1147     tty->print("[bad uncommon trap]");
1148     return 0;
1149   }
1150 #endif
1151   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();
1152 }
1153 
1154 #ifndef PRODUCT
1155 void CallStaticJavaNode::dump_spec(outputStream *st) const {
1156   st->print("# Static ");
1157   if (_name != nullptr) {
1158     st->print("%s", _name);
1159     int trap_req = uncommon_trap_request();
1160     if (trap_req != 0) {
1161       char buf[100];
1162       st->print("(%s)",
1163                  Deoptimization::format_trap_request(buf, sizeof(buf),
1164                                                      trap_req));
1165     }
1166     st->print(" ");
1167   }
1168   CallJavaNode::dump_spec(st);
1169 }
1170 
1171 void CallStaticJavaNode::dump_compact_spec(outputStream* st) const {
1172   if (_method) {
1173     _method->print_short_name(st);
1174   } else if (_name) {
1175     st->print("%s", _name);
1176   } else {
1177     st->print("<?>");
1178   }
1179 }
1180 #endif
1181 
1182 //=============================================================================
1183 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }
1184 bool CallDynamicJavaNode::cmp( const Node &n ) const {
1185   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;
1186   return CallJavaNode::cmp(call);
1187 }
1188 
1189 Node* CallDynamicJavaNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1190   CallGenerator* cg = generator();
1191   if (can_reshape && cg != nullptr) {
1192     assert(IncrementalInlineVirtual, "required");
1193     assert(cg->call_node() == this, "mismatch");
1194     assert(cg->is_virtual_late_inline(), "not virtual");
1195 
1196     // Recover symbolic info for method resolution.
1197     ciMethod* caller = jvms()->method();
1198     ciBytecodeStream iter(caller);
1199     iter.force_bci(jvms()->bci());
1200 
1201     bool             not_used1;
1202     ciSignature*     not_used2;
1203     ciMethod*        orig_callee  = iter.get_method(not_used1, &not_used2);  // callee in the bytecode
1204     ciKlass*         holder       = iter.get_declared_method_holder();
1205     if (orig_callee->is_method_handle_intrinsic()) {
1206       assert(_override_symbolic_info, "required");
1207       orig_callee = method();
1208       holder = method()->holder();
1209     }
1210 
1211     ciInstanceKlass* klass = ciEnv::get_instance_klass_for_declared_method_holder(holder);
1212 
1213     Node* receiver_node = in(TypeFunc::Parms);
1214     const TypeOopPtr* receiver_type = phase->type(receiver_node)->isa_oopptr();
1215 
1216     int  not_used3;
1217     bool call_does_dispatch;
1218     ciMethod* callee = phase->C->optimize_virtual_call(caller, klass, holder, orig_callee, receiver_type, true /*is_virtual*/,
1219                                                        call_does_dispatch, not_used3);  // out-parameters
1220     if (!call_does_dispatch) {
1221       // Register for late inlining.
1222       cg->set_callee_method(callee);
1223       phase->C->prepend_late_inline(cg); // MH late inlining prepends to the list, so do the same
1224       set_generator(nullptr);
1225     }
1226   }
1227   return CallNode::Ideal(phase, can_reshape);
1228 }
1229 
1230 #ifndef PRODUCT
1231 void CallDynamicJavaNode::dump_spec(outputStream *st) const {
1232   st->print("# Dynamic ");
1233   CallJavaNode::dump_spec(st);
1234 }
1235 #endif
1236 
1237 //=============================================================================
1238 uint CallRuntimeNode::size_of() const { return sizeof(*this); }
1239 bool CallRuntimeNode::cmp( const Node &n ) const {
1240   CallRuntimeNode &call = (CallRuntimeNode&)n;
1241   return CallNode::cmp(call) && !strcmp(_name,call._name);
1242 }
1243 #ifndef PRODUCT
1244 void CallRuntimeNode::dump_spec(outputStream *st) const {
1245   st->print("# ");
1246   st->print("%s", _name);
1247   CallNode::dump_spec(st);
1248 }
1249 #endif
1250 uint CallLeafVectorNode::size_of() const { return sizeof(*this); }
1251 bool CallLeafVectorNode::cmp( const Node &n ) const {
1252   CallLeafVectorNode &call = (CallLeafVectorNode&)n;
1253   return CallLeafNode::cmp(call) && _num_bits == call._num_bits;
1254 }
1255 
1256 //------------------------------calling_convention-----------------------------
1257 void CallRuntimeNode::calling_convention(BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt) const {
1258   SharedRuntime::c_calling_convention(sig_bt, parm_regs, argcnt);
1259 }
1260 
1261 void CallLeafVectorNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
1262 #ifdef ASSERT
1263   assert(tf()->range()->field_at(TypeFunc::Parms)->is_vect()->length_in_bytes() * BitsPerByte == _num_bits,
1264          "return vector size must match");
1265   const TypeTuple* d = tf()->domain();
1266   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1267     Node* arg = in(i);
1268     assert(arg->bottom_type()->is_vect()->length_in_bytes() * BitsPerByte == _num_bits,
1269            "vector argument size must match");
1270   }
1271 #endif
1272 
1273   SharedRuntime::vector_calling_convention(parm_regs, _num_bits, argcnt);
1274 }
1275 
1276 //=============================================================================
1277 //------------------------------calling_convention-----------------------------
1278 
1279 
1280 //=============================================================================
1281 #ifndef PRODUCT
1282 void CallLeafNode::dump_spec(outputStream *st) const {
1283   st->print("# ");
1284   st->print("%s", _name);
1285   CallNode::dump_spec(st);
1286 }
1287 #endif
1288 
1289 //=============================================================================
1290 
1291 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {
1292   assert(verify_jvms(jvms), "jvms must match");
1293   int loc = jvms->locoff() + idx;
1294   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {
1295     // If current local idx is top then local idx - 1 could
1296     // be a long/double that needs to be killed since top could
1297     // represent the 2nd half of the long/double.
1298     uint ideal = in(loc -1)->ideal_reg();
1299     if (ideal == Op_RegD || ideal == Op_RegL) {
1300       // set other (low index) half to top
1301       set_req(loc - 1, in(loc));
1302     }
1303   }
1304   set_req(loc, c);
1305 }
1306 
1307 uint SafePointNode::size_of() const { return sizeof(*this); }
1308 bool SafePointNode::cmp( const Node &n ) const {
1309   return (&n == this);          // Always fail except on self
1310 }
1311 
1312 //-------------------------set_next_exception----------------------------------
1313 void SafePointNode::set_next_exception(SafePointNode* n) {
1314   assert(n == nullptr || n->Opcode() == Op_SafePoint, "correct value for next_exception");
1315   if (len() == req()) {
1316     if (n != nullptr)  add_prec(n);
1317   } else {
1318     set_prec(req(), n);
1319   }
1320 }
1321 
1322 
1323 //----------------------------next_exception-----------------------------------
1324 SafePointNode* SafePointNode::next_exception() const {
1325   if (len() == req()) {
1326     return nullptr;
1327   } else {
1328     Node* n = in(req());
1329     assert(n == nullptr || n->Opcode() == Op_SafePoint, "no other uses of prec edges");
1330     return (SafePointNode*) n;
1331   }
1332 }
1333 
1334 
1335 //------------------------------Ideal------------------------------------------
1336 // Skip over any collapsed Regions
1337 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1338   assert(_jvms == nullptr || ((uintptr_t)_jvms->map() & 1) || _jvms->map() == this, "inconsistent JVMState");
1339   return remove_dead_region(phase, can_reshape) ? this : nullptr;
1340 }
1341 
1342 //------------------------------Identity---------------------------------------
1343 // Remove obviously duplicate safepoints
1344 Node* SafePointNode::Identity(PhaseGVN* phase) {
1345 
1346   // If you have back to back safepoints, remove one
1347   if (in(TypeFunc::Control)->is_SafePoint()) {
1348     Node* out_c = unique_ctrl_out_or_null();
1349     // This can be the safepoint of an outer strip mined loop if the inner loop's backedge was removed. Replacing the
1350     // outer loop's safepoint could confuse removal of the outer loop.
1351     if (out_c != nullptr && !out_c->is_OuterStripMinedLoopEnd()) {
1352       return in(TypeFunc::Control);
1353     }
1354   }
1355 
1356   // Transforming long counted loops requires a safepoint node. Do not
1357   // eliminate a safepoint until loop opts are over.
1358   if (in(0)->is_Proj() && !phase->C->major_progress()) {
1359     Node *n0 = in(0)->in(0);
1360     // Check if he is a call projection (except Leaf Call)
1361     if( n0->is_Catch() ) {
1362       n0 = n0->in(0)->in(0);
1363       assert( n0->is_Call(), "expect a call here" );
1364     }
1365     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {
1366       // Don't remove a safepoint belonging to an OuterStripMinedLoopEndNode.
1367       // If the loop dies, they will be removed together.
1368       if (has_out_with(Op_OuterStripMinedLoopEnd)) {
1369         return this;
1370       }
1371       // Useless Safepoint, so remove it
1372       return in(TypeFunc::Control);
1373     }
1374   }
1375 
1376   return this;
1377 }
1378 
1379 //------------------------------Value------------------------------------------
1380 const Type* SafePointNode::Value(PhaseGVN* phase) const {
1381   if (phase->type(in(0)) == Type::TOP) {
1382     return Type::TOP;
1383   }
1384   if (in(0) == this) {
1385     return Type::TOP; // Dead infinite loop
1386   }
1387   return Type::CONTROL;
1388 }
1389 
1390 #ifndef PRODUCT
1391 void SafePointNode::dump_spec(outputStream *st) const {
1392   st->print(" SafePoint ");
1393   _replaced_nodes.dump(st);
1394 }
1395 #endif
1396 
1397 const RegMask &SafePointNode::in_RegMask(uint idx) const {
1398   if( idx < TypeFunc::Parms ) return RegMask::Empty;
1399   // Values outside the domain represent debug info
1400   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1401 }
1402 const RegMask &SafePointNode::out_RegMask() const {
1403   return RegMask::Empty;
1404 }
1405 
1406 
1407 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {
1408   assert((int)grow_by > 0, "sanity");
1409   int monoff = jvms->monoff();
1410   int scloff = jvms->scloff();
1411   int endoff = jvms->endoff();
1412   assert(endoff == (int)req(), "no other states or debug info after me");
1413   Node* top = Compile::current()->top();
1414   for (uint i = 0; i < grow_by; i++) {
1415     ins_req(monoff, top);
1416   }
1417   jvms->set_monoff(monoff + grow_by);
1418   jvms->set_scloff(scloff + grow_by);
1419   jvms->set_endoff(endoff + grow_by);
1420 }
1421 
1422 void SafePointNode::push_monitor(const FastLockNode *lock) {
1423   // Add a LockNode, which points to both the original BoxLockNode (the
1424   // stack space for the monitor) and the Object being locked.
1425   const int MonitorEdges = 2;
1426   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1427   assert(req() == jvms()->endoff(), "correct sizing");
1428   int nextmon = jvms()->scloff();
1429   if (GenerateSynchronizationCode) {
1430     ins_req(nextmon,   lock->box_node());
1431     ins_req(nextmon+1, lock->obj_node());
1432   } else {
1433     Node* top = Compile::current()->top();
1434     ins_req(nextmon, top);
1435     ins_req(nextmon, top);
1436   }
1437   jvms()->set_scloff(nextmon + MonitorEdges);
1438   jvms()->set_endoff(req());
1439 }
1440 
1441 void SafePointNode::pop_monitor() {
1442   // Delete last monitor from debug info
1443   debug_only(int num_before_pop = jvms()->nof_monitors());
1444   const int MonitorEdges = 2;
1445   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1446   int scloff = jvms()->scloff();
1447   int endoff = jvms()->endoff();
1448   int new_scloff = scloff - MonitorEdges;
1449   int new_endoff = endoff - MonitorEdges;
1450   jvms()->set_scloff(new_scloff);
1451   jvms()->set_endoff(new_endoff);
1452   while (scloff > new_scloff)  del_req_ordered(--scloff);
1453   assert(jvms()->nof_monitors() == num_before_pop-1, "");
1454 }
1455 
1456 Node *SafePointNode::peek_monitor_box() const {
1457   int mon = jvms()->nof_monitors() - 1;
1458   assert(mon >= 0, "must have a monitor");
1459   return monitor_box(jvms(), mon);
1460 }
1461 
1462 Node *SafePointNode::peek_monitor_obj() const {
1463   int mon = jvms()->nof_monitors() - 1;
1464   assert(mon >= 0, "must have a monitor");
1465   return monitor_obj(jvms(), mon);
1466 }
1467 
1468 Node* SafePointNode::peek_operand(uint off) const {
1469   assert(jvms()->sp() > 0, "must have an operand");
1470   assert(off < jvms()->sp(), "off is out-of-range");
1471   return stack(jvms(), jvms()->sp() - off - 1);
1472 }
1473 
1474 // Do we Match on this edge index or not?  Match no edges
1475 uint SafePointNode::match_edge(uint idx) const {
1476   return (TypeFunc::Parms == idx);
1477 }
1478 
1479 void SafePointNode::disconnect_from_root(PhaseIterGVN *igvn) {
1480   assert(Opcode() == Op_SafePoint, "only value for safepoint in loops");
1481   int nb = igvn->C->root()->find_prec_edge(this);
1482   if (nb != -1) {
1483     igvn->delete_precedence_of(igvn->C->root(), nb);
1484   }
1485 }
1486 
1487 //==============  SafePointScalarObjectNode  ==============
1488 
1489 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp, Node* alloc, uint first_index, uint depth, uint n_fields) :
1490   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
1491   _first_index(first_index),
1492   _depth(depth),
1493   _n_fields(n_fields),
1494   _alloc(alloc)
1495 {
1496 #ifdef ASSERT
1497   if (!alloc->is_Allocate() && !(alloc->Opcode() == Op_VectorBox)) {
1498     alloc->dump();
1499     assert(false, "unexpected call node");
1500   }
1501 #endif
1502   init_class_id(Class_SafePointScalarObject);
1503 }
1504 
1505 // Do not allow value-numbering for SafePointScalarObject node.
1506 uint SafePointScalarObjectNode::hash() const { return NO_HASH; }
1507 bool SafePointScalarObjectNode::cmp( const Node &n ) const {
1508   return (&n == this); // Always fail except on self
1509 }
1510 
1511 uint SafePointScalarObjectNode::ideal_reg() const {
1512   return 0; // No matching to machine instruction
1513 }
1514 
1515 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {
1516   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1517 }
1518 
1519 const RegMask &SafePointScalarObjectNode::out_RegMask() const {
1520   return RegMask::Empty;
1521 }
1522 
1523 uint SafePointScalarObjectNode::match_edge(uint idx) const {
1524   return 0;
1525 }
1526 
1527 SafePointScalarObjectNode*
1528 SafePointScalarObjectNode::clone(Dict* sosn_map, bool& new_node) const {
1529   void* cached = (*sosn_map)[(void*)this];
1530   if (cached != nullptr) {
1531     new_node = false;
1532     return (SafePointScalarObjectNode*)cached;
1533   }
1534   new_node = true;
1535   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();
1536   sosn_map->Insert((void*)this, (void*)res);
1537   return res;
1538 }
1539 
1540 
1541 #ifndef PRODUCT
1542 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {
1543   st->print(" # fields@[%d..%d]", first_index(), first_index() + n_fields() - 1);
1544 }
1545 #endif
1546 
1547 //==============  SafePointScalarMergeNode  ==============
1548 
1549 SafePointScalarMergeNode::SafePointScalarMergeNode(const TypeOopPtr* tp, int merge_pointer_idx) :
1550   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
1551   _merge_pointer_idx(merge_pointer_idx)
1552 {
1553   init_class_id(Class_SafePointScalarMerge);
1554 }
1555 
1556 // Do not allow value-numbering for SafePointScalarMerge node.
1557 uint SafePointScalarMergeNode::hash() const { return NO_HASH; }
1558 bool SafePointScalarMergeNode::cmp( const Node &n ) const {
1559   return (&n == this); // Always fail except on self
1560 }
1561 
1562 uint SafePointScalarMergeNode::ideal_reg() const {
1563   return 0; // No matching to machine instruction
1564 }
1565 
1566 const RegMask &SafePointScalarMergeNode::in_RegMask(uint idx) const {
1567   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1568 }
1569 
1570 const RegMask &SafePointScalarMergeNode::out_RegMask() const {
1571   return RegMask::Empty;
1572 }
1573 
1574 uint SafePointScalarMergeNode::match_edge(uint idx) const {
1575   return 0;
1576 }
1577 
1578 SafePointScalarMergeNode*
1579 SafePointScalarMergeNode::clone(Dict* sosn_map, bool& new_node) const {
1580   void* cached = (*sosn_map)[(void*)this];
1581   if (cached != nullptr) {
1582     new_node = false;
1583     return (SafePointScalarMergeNode*)cached;
1584   }
1585   new_node = true;
1586   SafePointScalarMergeNode* res = (SafePointScalarMergeNode*)Node::clone();
1587   sosn_map->Insert((void*)this, (void*)res);
1588   return res;
1589 }
1590 
1591 #ifndef PRODUCT
1592 void SafePointScalarMergeNode::dump_spec(outputStream *st) const {
1593   st->print(" # merge_pointer_idx=%d, scalarized_objects=%d", _merge_pointer_idx, req()-1);
1594 }
1595 #endif
1596 
1597 //=============================================================================
1598 uint AllocateNode::size_of() const { return sizeof(*this); }
1599 
1600 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,
1601                            Node *ctrl, Node *mem, Node *abio,
1602                            Node *size, Node *klass_node, Node *initial_test)
1603   : CallNode(atype, nullptr, TypeRawPtr::BOTTOM)
1604 {
1605   init_class_id(Class_Allocate);
1606   init_flags(Flag_is_macro);
1607   _is_scalar_replaceable = false;
1608   _is_non_escaping = false;
1609   _is_allocation_MemBar_redundant = false;
1610   Node *topnode = C->top();
1611 
1612   init_req( TypeFunc::Control  , ctrl );
1613   init_req( TypeFunc::I_O      , abio );
1614   init_req( TypeFunc::Memory   , mem );
1615   init_req( TypeFunc::ReturnAdr, topnode );
1616   init_req( TypeFunc::FramePtr , topnode );
1617   init_req( AllocSize          , size);
1618   init_req( KlassNode          , klass_node);
1619   init_req( InitialTest        , initial_test);
1620   init_req( ALength            , topnode);
1621   init_req( ValidLengthTest    , topnode);
1622   C->add_macro_node(this);
1623 }
1624 
1625 void AllocateNode::compute_MemBar_redundancy(ciMethod* initializer)
1626 {
1627   assert(initializer != nullptr && initializer->is_object_initializer(),
1628          "unexpected initializer method");
1629   BCEscapeAnalyzer* analyzer = initializer->get_bcea();
1630   if (analyzer == nullptr) {
1631     return;
1632   }
1633 
1634   // Allocation node is first parameter in its initializer
1635   if (analyzer->is_arg_stack(0) || analyzer->is_arg_local(0)) {
1636     _is_allocation_MemBar_redundant = true;
1637   }
1638 }
1639 Node *AllocateNode::make_ideal_mark(PhaseGVN *phase, Node* obj, Node* control, Node* mem) {
1640   Node* mark_node = nullptr;
1641   if (UseCompactObjectHeaders) {
1642     Node* klass_node = in(AllocateNode::KlassNode);
1643     Node* proto_adr = phase->transform(new AddPNode(klass_node, klass_node, phase->MakeConX(in_bytes(Klass::prototype_header_offset()))));
1644     mark_node = LoadNode::make(*phase, control, mem, proto_adr, TypeRawPtr::BOTTOM, TypeX_X, TypeX_X->basic_type(), MemNode::unordered);
1645   } else {
1646     // For now only enable fast locking for non-array types
1647     mark_node = phase->MakeConX(markWord::prototype().value());
1648   }
1649   return mark_node;
1650 }
1651 
1652 // Retrieve the length from the AllocateArrayNode. Narrow the type with a
1653 // CastII, if appropriate.  If we are not allowed to create new nodes, and
1654 // a CastII is appropriate, return null.
1655 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseValues* phase, bool allow_new_nodes) {
1656   Node *length = in(AllocateNode::ALength);
1657   assert(length != nullptr, "length is not null");
1658 
1659   const TypeInt* length_type = phase->find_int_type(length);
1660   const TypeAryPtr* ary_type = oop_type->isa_aryptr();
1661 
1662   if (ary_type != nullptr && length_type != nullptr) {
1663     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);
1664     if (narrow_length_type != length_type) {
1665       // Assert one of:
1666       //   - the narrow_length is 0
1667       //   - the narrow_length is not wider than length
1668       assert(narrow_length_type == TypeInt::ZERO ||
1669              (length_type->is_con() && narrow_length_type->is_con() &&
1670               (narrow_length_type->_hi <= length_type->_lo)) ||
1671              (narrow_length_type->_hi <= length_type->_hi &&
1672               narrow_length_type->_lo >= length_type->_lo),
1673              "narrow type must be narrower than length type");
1674 
1675       // Return null if new nodes are not allowed
1676       if (!allow_new_nodes) {
1677         return nullptr;
1678       }
1679       // Create a cast which is control dependent on the initialization to
1680       // propagate the fact that the array length must be positive.
1681       InitializeNode* init = initialization();
1682       if (init != nullptr) {
1683         length = new CastIINode(init->proj_out_or_null(TypeFunc::Control), length, narrow_length_type);
1684       }
1685     }
1686   }
1687 
1688   return length;
1689 }
1690 
1691 //=============================================================================
1692 const TypeFunc* LockNode::_lock_type_Type = nullptr;
1693 
1694 uint LockNode::size_of() const { return sizeof(*this); }
1695 
1696 // Redundant lock elimination
1697 //
1698 // There are various patterns of locking where we release and
1699 // immediately reacquire a lock in a piece of code where no operations
1700 // occur in between that would be observable.  In those cases we can
1701 // skip releasing and reacquiring the lock without violating any
1702 // fairness requirements.  Doing this around a loop could cause a lock
1703 // to be held for a very long time so we concentrate on non-looping
1704 // control flow.  We also require that the operations are fully
1705 // redundant meaning that we don't introduce new lock operations on
1706 // some paths so to be able to eliminate it on others ala PRE.  This
1707 // would probably require some more extensive graph manipulation to
1708 // guarantee that the memory edges were all handled correctly.
1709 //
1710 // Assuming p is a simple predicate which can't trap in any way and s
1711 // is a synchronized method consider this code:
1712 //
1713 //   s();
1714 //   if (p)
1715 //     s();
1716 //   else
1717 //     s();
1718 //   s();
1719 //
1720 // 1. The unlocks of the first call to s can be eliminated if the
1721 // locks inside the then and else branches are eliminated.
1722 //
1723 // 2. The unlocks of the then and else branches can be eliminated if
1724 // the lock of the final call to s is eliminated.
1725 //
1726 // Either of these cases subsumes the simple case of sequential control flow
1727 //
1728 // Additionally we can eliminate versions without the else case:
1729 //
1730 //   s();
1731 //   if (p)
1732 //     s();
1733 //   s();
1734 //
1735 // 3. In this case we eliminate the unlock of the first s, the lock
1736 // and unlock in the then case and the lock in the final s.
1737 //
1738 // Note also that in all these cases the then/else pieces don't have
1739 // to be trivial as long as they begin and end with synchronization
1740 // operations.
1741 //
1742 //   s();
1743 //   if (p)
1744 //     s();
1745 //     f();
1746 //     s();
1747 //   s();
1748 //
1749 // The code will work properly for this case, leaving in the unlock
1750 // before the call to f and the relock after it.
1751 //
1752 // A potentially interesting case which isn't handled here is when the
1753 // locking is partially redundant.
1754 //
1755 //   s();
1756 //   if (p)
1757 //     s();
1758 //
1759 // This could be eliminated putting unlocking on the else case and
1760 // eliminating the first unlock and the lock in the then side.
1761 // Alternatively the unlock could be moved out of the then side so it
1762 // was after the merge and the first unlock and second lock
1763 // eliminated.  This might require less manipulation of the memory
1764 // state to get correct.
1765 //
1766 // Additionally we might allow work between a unlock and lock before
1767 // giving up eliminating the locks.  The current code disallows any
1768 // conditional control flow between these operations.  A formulation
1769 // similar to partial redundancy elimination computing the
1770 // availability of unlocking and the anticipatability of locking at a
1771 // program point would allow detection of fully redundant locking with
1772 // some amount of work in between.  I'm not sure how often I really
1773 // think that would occur though.  Most of the cases I've seen
1774 // indicate it's likely non-trivial work would occur in between.
1775 // There may be other more complicated constructs where we could
1776 // eliminate locking but I haven't seen any others appear as hot or
1777 // interesting.
1778 //
1779 // Locking and unlocking have a canonical form in ideal that looks
1780 // roughly like this:
1781 //
1782 //              <obj>
1783 //                | \\------+
1784 //                |  \       \
1785 //                | BoxLock   \
1786 //                |  |   |     \
1787 //                |  |    \     \
1788 //                |  |   FastLock
1789 //                |  |   /
1790 //                |  |  /
1791 //                |  |  |
1792 //
1793 //               Lock
1794 //                |
1795 //            Proj #0
1796 //                |
1797 //            MembarAcquire
1798 //                |
1799 //            Proj #0
1800 //
1801 //            MembarRelease
1802 //                |
1803 //            Proj #0
1804 //                |
1805 //              Unlock
1806 //                |
1807 //            Proj #0
1808 //
1809 //
1810 // This code proceeds by processing Lock nodes during PhaseIterGVN
1811 // and searching back through its control for the proper code
1812 // patterns.  Once it finds a set of lock and unlock operations to
1813 // eliminate they are marked as eliminatable which causes the
1814 // expansion of the Lock and Unlock macro nodes to make the operation a NOP
1815 //
1816 //=============================================================================
1817 
1818 //
1819 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:
1820 //   - copy regions.  (These may not have been optimized away yet.)
1821 //   - eliminated locking nodes
1822 //
1823 static Node *next_control(Node *ctrl) {
1824   if (ctrl == nullptr)
1825     return nullptr;
1826   while (1) {
1827     if (ctrl->is_Region()) {
1828       RegionNode *r = ctrl->as_Region();
1829       Node *n = r->is_copy();
1830       if (n == nullptr)
1831         break;  // hit a region, return it
1832       else
1833         ctrl = n;
1834     } else if (ctrl->is_Proj()) {
1835       Node *in0 = ctrl->in(0);
1836       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {
1837         ctrl = in0->in(0);
1838       } else {
1839         break;
1840       }
1841     } else {
1842       break; // found an interesting control
1843     }
1844   }
1845   return ctrl;
1846 }
1847 //
1848 // Given a control, see if it's the control projection of an Unlock which
1849 // operating on the same object as lock.
1850 //
1851 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,
1852                                             GrowableArray<AbstractLockNode*> &lock_ops) {
1853   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : nullptr;
1854   if (ctrl_proj != nullptr && ctrl_proj->_con == TypeFunc::Control) {
1855     Node *n = ctrl_proj->in(0);
1856     if (n != nullptr && n->is_Unlock()) {
1857       UnlockNode *unlock = n->as_Unlock();
1858       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1859       Node* lock_obj = bs->step_over_gc_barrier(lock->obj_node());
1860       Node* unlock_obj = bs->step_over_gc_barrier(unlock->obj_node());
1861       if (lock_obj->eqv_uncast(unlock_obj) &&
1862           BoxLockNode::same_slot(lock->box_node(), unlock->box_node()) &&
1863           !unlock->is_eliminated()) {
1864         lock_ops.append(unlock);
1865         return true;
1866       }
1867     }
1868   }
1869   return false;
1870 }
1871 
1872 //
1873 // Find the lock matching an unlock.  Returns null if a safepoint
1874 // or complicated control is encountered first.
1875 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {
1876   LockNode *lock_result = nullptr;
1877   // find the matching lock, or an intervening safepoint
1878   Node *ctrl = next_control(unlock->in(0));
1879   while (1) {
1880     assert(ctrl != nullptr, "invalid control graph");
1881     assert(!ctrl->is_Start(), "missing lock for unlock");
1882     if (ctrl->is_top()) break;  // dead control path
1883     if (ctrl->is_Proj()) ctrl = ctrl->in(0);
1884     if (ctrl->is_SafePoint()) {
1885         break;  // found a safepoint (may be the lock we are searching for)
1886     } else if (ctrl->is_Region()) {
1887       // Check for a simple diamond pattern.  Punt on anything more complicated
1888       if (ctrl->req() == 3 && ctrl->in(1) != nullptr && ctrl->in(2) != nullptr) {
1889         Node *in1 = next_control(ctrl->in(1));
1890         Node *in2 = next_control(ctrl->in(2));
1891         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||
1892              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {
1893           ctrl = next_control(in1->in(0)->in(0));
1894         } else {
1895           break;
1896         }
1897       } else {
1898         break;
1899       }
1900     } else {
1901       ctrl = next_control(ctrl->in(0));  // keep searching
1902     }
1903   }
1904   if (ctrl->is_Lock()) {
1905     LockNode *lock = ctrl->as_Lock();
1906     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1907     Node* lock_obj = bs->step_over_gc_barrier(lock->obj_node());
1908     Node* unlock_obj = bs->step_over_gc_barrier(unlock->obj_node());
1909     if (lock_obj->eqv_uncast(unlock_obj) &&
1910         BoxLockNode::same_slot(lock->box_node(), unlock->box_node())) {
1911       lock_result = lock;
1912     }
1913   }
1914   return lock_result;
1915 }
1916 
1917 // This code corresponds to case 3 above.
1918 
1919 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,
1920                                                        GrowableArray<AbstractLockNode*> &lock_ops) {
1921   Node* if_node = node->in(0);
1922   bool  if_true = node->is_IfTrue();
1923 
1924   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {
1925     Node *lock_ctrl = next_control(if_node->in(0));
1926     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {
1927       Node* lock1_node = nullptr;
1928       ProjNode* proj = if_node->as_If()->proj_out(!if_true);
1929       if (if_true) {
1930         if (proj->is_IfFalse() && proj->outcnt() == 1) {
1931           lock1_node = proj->unique_out();
1932         }
1933       } else {
1934         if (proj->is_IfTrue() && proj->outcnt() == 1) {
1935           lock1_node = proj->unique_out();
1936         }
1937       }
1938       if (lock1_node != nullptr && lock1_node->is_Lock()) {
1939         LockNode *lock1 = lock1_node->as_Lock();
1940         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1941         Node* lock_obj = bs->step_over_gc_barrier(lock->obj_node());
1942         Node* lock1_obj = bs->step_over_gc_barrier(lock1->obj_node());
1943         if (lock_obj->eqv_uncast(lock1_obj) &&
1944             BoxLockNode::same_slot(lock->box_node(), lock1->box_node()) &&
1945             !lock1->is_eliminated()) {
1946           lock_ops.append(lock1);
1947           return true;
1948         }
1949       }
1950     }
1951   }
1952 
1953   lock_ops.trunc_to(0);
1954   return false;
1955 }
1956 
1957 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,
1958                                GrowableArray<AbstractLockNode*> &lock_ops) {
1959   // check each control merging at this point for a matching unlock.
1960   // in(0) should be self edge so skip it.
1961   for (int i = 1; i < (int)region->req(); i++) {
1962     Node *in_node = next_control(region->in(i));
1963     if (in_node != nullptr) {
1964       if (find_matching_unlock(in_node, lock, lock_ops)) {
1965         // found a match so keep on checking.
1966         continue;
1967       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {
1968         continue;
1969       }
1970 
1971       // If we fall through to here then it was some kind of node we
1972       // don't understand or there wasn't a matching unlock, so give
1973       // up trying to merge locks.
1974       lock_ops.trunc_to(0);
1975       return false;
1976     }
1977   }
1978   return true;
1979 
1980 }
1981 
1982 // Check that all locks/unlocks associated with object come from balanced regions.
1983 bool AbstractLockNode::is_balanced() {
1984   Node* obj = obj_node();
1985   for (uint j = 0; j < obj->outcnt(); j++) {
1986     Node* n = obj->raw_out(j);
1987     if (n->is_AbstractLock() &&
1988         n->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
1989       BoxLockNode* n_box = n->as_AbstractLock()->box_node()->as_BoxLock();
1990       if (n_box->is_unbalanced()) {
1991         return false;
1992       }
1993     }
1994   }
1995   return true;
1996 }
1997 
1998 const char* AbstractLockNode::_kind_names[] = {"Regular", "NonEscObj", "Coarsened", "Nested"};
1999 
2000 const char * AbstractLockNode::kind_as_string() const {
2001   return _kind_names[_kind];
2002 }
2003 
2004 #ifndef PRODUCT
2005 //
2006 // Create a counter which counts the number of times this lock is acquired
2007 //
2008 void AbstractLockNode::create_lock_counter(JVMState* state) {
2009   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);
2010 }
2011 
2012 void AbstractLockNode::set_eliminated_lock_counter() {
2013   if (_counter) {
2014     // Update the counter to indicate that this lock was eliminated.
2015     // The counter update code will stay around even though the
2016     // optimizer will eliminate the lock operation itself.
2017     _counter->set_tag(NamedCounter::EliminatedLockCounter);
2018   }
2019 }
2020 
2021 void AbstractLockNode::dump_spec(outputStream* st) const {
2022   st->print("%s ", _kind_names[_kind]);
2023   CallNode::dump_spec(st);
2024 }
2025 
2026 void AbstractLockNode::dump_compact_spec(outputStream* st) const {
2027   st->print("%s", _kind_names[_kind]);
2028 }
2029 #endif
2030 
2031 //=============================================================================
2032 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2033 
2034   // perform any generic optimizations first (returns 'this' or null)
2035   Node *result = SafePointNode::Ideal(phase, can_reshape);
2036   if (result != nullptr)  return result;
2037   // Don't bother trying to transform a dead node
2038   if (in(0) && in(0)->is_top())  return nullptr;
2039 
2040   // Now see if we can optimize away this lock.  We don't actually
2041   // remove the locking here, we simply set the _eliminate flag which
2042   // prevents macro expansion from expanding the lock.  Since we don't
2043   // modify the graph, the value returned from this function is the
2044   // one computed above.
2045   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
2046     //
2047     // If we are locking an non-escaped object, the lock/unlock is unnecessary
2048     //
2049     ConnectionGraph *cgr = phase->C->congraph();
2050     if (cgr != nullptr && cgr->can_eliminate_lock(this)) {
2051       assert(!is_eliminated() || is_coarsened(), "sanity");
2052       // The lock could be marked eliminated by lock coarsening
2053       // code during first IGVN before EA. Replace coarsened flag
2054       // to eliminate all associated locks/unlocks.
2055 #ifdef ASSERT
2056       this->log_lock_optimization(phase->C,"eliminate_lock_set_non_esc1");
2057 #endif
2058       this->set_non_esc_obj();
2059       return result;
2060     }
2061 
2062     if (!phase->C->do_locks_coarsening()) {
2063       return result; // Compiling without locks coarsening
2064     }
2065     //
2066     // Try lock coarsening
2067     //
2068     PhaseIterGVN* iter = phase->is_IterGVN();
2069     if (iter != nullptr && !is_eliminated()) {
2070 
2071       GrowableArray<AbstractLockNode*>   lock_ops;
2072 
2073       Node *ctrl = next_control(in(0));
2074 
2075       // now search back for a matching Unlock
2076       if (find_matching_unlock(ctrl, this, lock_ops)) {
2077         // found an unlock directly preceding this lock.  This is the
2078         // case of single unlock directly control dependent on a
2079         // single lock which is the trivial version of case 1 or 2.
2080       } else if (ctrl->is_Region() ) {
2081         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {
2082         // found lock preceded by multiple unlocks along all paths
2083         // joining at this point which is case 3 in description above.
2084         }
2085       } else {
2086         // see if this lock comes from either half of an if and the
2087         // predecessors merges unlocks and the other half of the if
2088         // performs a lock.
2089         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {
2090           // found unlock splitting to an if with locks on both branches.
2091         }
2092       }
2093 
2094       if (lock_ops.length() > 0) {
2095         // add ourselves to the list of locks to be eliminated.
2096         lock_ops.append(this);
2097 
2098   #ifndef PRODUCT
2099         if (PrintEliminateLocks) {
2100           int locks = 0;
2101           int unlocks = 0;
2102           if (Verbose) {
2103             tty->print_cr("=== Locks coarsening ===");
2104             tty->print("Obj: ");
2105             obj_node()->dump();
2106           }
2107           for (int i = 0; i < lock_ops.length(); i++) {
2108             AbstractLockNode* lock = lock_ops.at(i);
2109             if (lock->Opcode() == Op_Lock)
2110               locks++;
2111             else
2112               unlocks++;
2113             if (Verbose) {
2114               tty->print("Box %d: ", i);
2115               box_node()->dump();
2116               tty->print(" %d: ", i);
2117               lock->dump();
2118             }
2119           }
2120           tty->print_cr("=== Coarsened %d unlocks and %d locks", unlocks, locks);
2121         }
2122   #endif
2123 
2124         // for each of the identified locks, mark them
2125         // as eliminatable
2126         for (int i = 0; i < lock_ops.length(); i++) {
2127           AbstractLockNode* lock = lock_ops.at(i);
2128 
2129           // Mark it eliminated by coarsening and update any counters
2130 #ifdef ASSERT
2131           lock->log_lock_optimization(phase->C, "eliminate_lock_set_coarsened");
2132 #endif
2133           lock->set_coarsened();
2134         }
2135         // Record this coarsened group.
2136         phase->C->add_coarsened_locks(lock_ops);
2137       } else if (ctrl->is_Region() &&
2138                  iter->_worklist.member(ctrl)) {
2139         // We weren't able to find any opportunities but the region this
2140         // lock is control dependent on hasn't been processed yet so put
2141         // this lock back on the worklist so we can check again once any
2142         // region simplification has occurred.
2143         iter->_worklist.push(this);
2144       }
2145     }
2146   }
2147 
2148   return result;
2149 }
2150 
2151 //=============================================================================
2152 bool LockNode::is_nested_lock_region() {
2153   return is_nested_lock_region(nullptr);
2154 }
2155 
2156 // p is used for access to compilation log; no logging if null
2157 bool LockNode::is_nested_lock_region(Compile * c) {
2158   BoxLockNode* box = box_node()->as_BoxLock();
2159   int stk_slot = box->stack_slot();
2160   if (stk_slot <= 0) {
2161 #ifdef ASSERT
2162     this->log_lock_optimization(c, "eliminate_lock_INLR_1");
2163 #endif
2164     return false; // External lock or it is not Box (Phi node).
2165   }
2166 
2167   // Ignore complex cases: merged locks or multiple locks.
2168   Node* obj = obj_node();
2169   LockNode* unique_lock = nullptr;
2170   Node* bad_lock = nullptr;
2171   if (!box->is_simple_lock_region(&unique_lock, obj, &bad_lock)) {
2172 #ifdef ASSERT
2173     this->log_lock_optimization(c, "eliminate_lock_INLR_2a", bad_lock);
2174 #endif
2175     return false;
2176   }
2177   if (unique_lock != this) {
2178 #ifdef ASSERT
2179     this->log_lock_optimization(c, "eliminate_lock_INLR_2b", (unique_lock != nullptr ? unique_lock : bad_lock));
2180     if (PrintEliminateLocks && Verbose) {
2181       tty->print_cr("=============== unique_lock != this ============");
2182       tty->print(" this: ");
2183       this->dump();
2184       tty->print(" box: ");
2185       box->dump();
2186       tty->print(" obj: ");
2187       obj->dump();
2188       if (unique_lock != nullptr) {
2189         tty->print(" unique_lock: ");
2190         unique_lock->dump();
2191       }
2192       if (bad_lock != nullptr) {
2193         tty->print(" bad_lock: ");
2194         bad_lock->dump();
2195       }
2196       tty->print_cr("===============");
2197     }
2198 #endif
2199     return false;
2200   }
2201 
2202   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2203   obj = bs->step_over_gc_barrier(obj);
2204   // Look for external lock for the same object.
2205   SafePointNode* sfn = this->as_SafePoint();
2206   JVMState* youngest_jvms = sfn->jvms();
2207   int max_depth = youngest_jvms->depth();
2208   for (int depth = 1; depth <= max_depth; depth++) {
2209     JVMState* jvms = youngest_jvms->of_depth(depth);
2210     int num_mon  = jvms->nof_monitors();
2211     // Loop over monitors
2212     for (int idx = 0; idx < num_mon; idx++) {
2213       Node* obj_node = sfn->monitor_obj(jvms, idx);
2214       obj_node = bs->step_over_gc_barrier(obj_node);
2215       BoxLockNode* box_node = sfn->monitor_box(jvms, idx)->as_BoxLock();
2216       if ((box_node->stack_slot() < stk_slot) && obj_node->eqv_uncast(obj)) {
2217         box->set_nested();
2218         return true;
2219       }
2220     }
2221   }
2222 #ifdef ASSERT
2223   this->log_lock_optimization(c, "eliminate_lock_INLR_3");
2224 #endif
2225   return false;
2226 }
2227 
2228 //=============================================================================
2229 uint UnlockNode::size_of() const { return sizeof(*this); }
2230 
2231 //=============================================================================
2232 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2233 
2234   // perform any generic optimizations first (returns 'this' or null)
2235   Node *result = SafePointNode::Ideal(phase, can_reshape);
2236   if (result != nullptr)  return result;
2237   // Don't bother trying to transform a dead node
2238   if (in(0) && in(0)->is_top())  return nullptr;
2239 
2240   // Now see if we can optimize away this unlock.  We don't actually
2241   // remove the unlocking here, we simply set the _eliminate flag which
2242   // prevents macro expansion from expanding the unlock.  Since we don't
2243   // modify the graph, the value returned from this function is the
2244   // one computed above.
2245   // Escape state is defined after Parse phase.
2246   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
2247     //
2248     // If we are unlocking an non-escaped object, the lock/unlock is unnecessary.
2249     //
2250     ConnectionGraph *cgr = phase->C->congraph();
2251     if (cgr != nullptr && cgr->can_eliminate_lock(this)) {
2252       assert(!is_eliminated() || is_coarsened(), "sanity");
2253       // The lock could be marked eliminated by lock coarsening
2254       // code during first IGVN before EA. Replace coarsened flag
2255       // to eliminate all associated locks/unlocks.
2256 #ifdef ASSERT
2257       this->log_lock_optimization(phase->C, "eliminate_lock_set_non_esc2");
2258 #endif
2259       this->set_non_esc_obj();
2260     }
2261   }
2262   return result;
2263 }
2264 
2265 void AbstractLockNode::log_lock_optimization(Compile *C, const char * tag, Node* bad_lock)  const {
2266   if (C == nullptr) {
2267     return;
2268   }
2269   CompileLog* log = C->log();
2270   if (log != nullptr) {
2271     Node* box = box_node();
2272     Node* obj = obj_node();
2273     int box_id = box != nullptr ? box->_idx : -1;
2274     int obj_id = obj != nullptr ? obj->_idx : -1;
2275 
2276     log->begin_head("%s compile_id='%d' lock_id='%d' class='%s' kind='%s' box_id='%d' obj_id='%d' bad_id='%d'",
2277           tag, C->compile_id(), this->_idx,
2278           is_Unlock() ? "unlock" : is_Lock() ? "lock" : "?",
2279           kind_as_string(), box_id, obj_id, (bad_lock != nullptr ? bad_lock->_idx : -1));
2280     log->stamp();
2281     log->end_head();
2282     JVMState* p = is_Unlock() ? (as_Unlock()->dbg_jvms()) : jvms();
2283     while (p != nullptr) {
2284       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
2285       p = p->caller();
2286     }
2287     log->tail(tag);
2288   }
2289 }
2290 
2291 bool CallNode::may_modify_arraycopy_helper(const TypeOopPtr* dest_t, const TypeOopPtr* t_oop, PhaseValues* phase) {
2292   if (dest_t->is_known_instance() && t_oop->is_known_instance()) {
2293     return dest_t->instance_id() == t_oop->instance_id();
2294   }
2295 
2296   if (dest_t->isa_instptr() && !dest_t->is_instptr()->instance_klass()->equals(phase->C->env()->Object_klass())) {
2297     // clone
2298     if (t_oop->isa_aryptr()) {
2299       return false;
2300     }
2301     if (!t_oop->isa_instptr()) {
2302       return true;
2303     }
2304     if (dest_t->maybe_java_subtype_of(t_oop) || t_oop->maybe_java_subtype_of(dest_t)) {
2305       return true;
2306     }
2307     // unrelated
2308     return false;
2309   }
2310 
2311   if (dest_t->isa_aryptr()) {
2312     // arraycopy or array clone
2313     if (t_oop->isa_instptr()) {
2314       return false;
2315     }
2316     if (!t_oop->isa_aryptr()) {
2317       return true;
2318     }
2319 
2320     const Type* elem = dest_t->is_aryptr()->elem();
2321     if (elem == Type::BOTTOM) {
2322       // An array but we don't know what elements are
2323       return true;
2324     }
2325 
2326     dest_t = dest_t->add_offset(Type::OffsetBot)->is_oopptr();
2327     uint dest_alias = phase->C->get_alias_index(dest_t);
2328     uint t_oop_alias = phase->C->get_alias_index(t_oop);
2329 
2330     return dest_alias == t_oop_alias;
2331   }
2332 
2333   return true;
2334 }