1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "ci/bcEscapeAnalyzer.hpp"
  27 #include "compiler/oopMap.hpp"
  28 #include "opto/callGenerator.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/escape.hpp"
  31 #include "opto/locknode.hpp"
  32 #include "opto/machnode.hpp"
  33 #include "opto/matcher.hpp"
  34 #include "opto/parse.hpp"
  35 #include "opto/regalloc.hpp"
  36 #include "opto/regmask.hpp"
  37 #include "opto/rootnode.hpp"
  38 #include "opto/runtime.hpp"
  39 
  40 // Portions of code courtesy of Clifford Click
  41 
  42 // Optimization - Graph Style
  43 
  44 //=============================================================================
  45 uint StartNode::size_of() const { return sizeof(*this); }
  46 uint StartNode::cmp( const Node &n ) const
  47 { return _domain == ((StartNode&)n)._domain; }
  48 const Type *StartNode::bottom_type() const { return _domain; }
  49 const Type *StartNode::Value(PhaseTransform *phase) const { return _domain; }
  50 #ifndef PRODUCT
  51 void StartNode::dump_spec(outputStream *st) const { st->print(" #"); _domain->dump_on(st);}
  52 #endif
  53 
  54 //------------------------------Ideal------------------------------------------
  55 Node *StartNode::Ideal(PhaseGVN *phase, bool can_reshape){
  56   return remove_dead_region(phase, can_reshape) ? this : NULL;
  57 }
  58 
  59 //------------------------------calling_convention-----------------------------
  60 void StartNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
  61   Matcher::calling_convention( sig_bt, parm_regs, argcnt, false );
  62 }
  63 
  64 //------------------------------Registers--------------------------------------
  65 const RegMask &StartNode::in_RegMask(uint) const {
  66   return RegMask::Empty;
  67 }
  68 
  69 //------------------------------match------------------------------------------
  70 // Construct projections for incoming parameters, and their RegMask info
  71 Node *StartNode::match( const ProjNode *proj, const Matcher *match ) {
  72   switch (proj->_con) {
  73   case TypeFunc::Control:
  74   case TypeFunc::I_O:
  75   case TypeFunc::Memory:
  76     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
  77   case TypeFunc::FramePtr:
  78     return new (match->C) MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);
  79   case TypeFunc::ReturnAdr:
  80     return new (match->C) MachProjNode(this,proj->_con,match->_return_addr_mask,Op_RegP);
  81   case TypeFunc::Parms:
  82   default: {
  83       uint parm_num = proj->_con - TypeFunc::Parms;
  84       const Type *t = _domain->field_at(proj->_con);
  85       if (t->base() == Type::Half)  // 2nd half of Longs and Doubles
  86         return new (match->C) ConNode(Type::TOP);
  87       uint ideal_reg = t->ideal_reg();
  88       RegMask &rm = match->_calling_convention_mask[parm_num];
  89       return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);
  90     }
  91   }
  92   return NULL;
  93 }
  94 
  95 //------------------------------StartOSRNode----------------------------------
  96 // The method start node for an on stack replacement adapter
  97 
  98 //------------------------------osr_domain-----------------------------
  99 const TypeTuple *StartOSRNode::osr_domain() {
 100   const Type **fields = TypeTuple::fields(2);
 101   fields[TypeFunc::Parms+0] = TypeRawPtr::BOTTOM;  // address of osr buffer
 102 
 103   return TypeTuple::make(TypeFunc::Parms+1, fields);
 104 }
 105 
 106 //=============================================================================
 107 const char * const ParmNode::names[TypeFunc::Parms+1] = {
 108   "Control", "I_O", "Memory", "FramePtr", "ReturnAdr", "Parms"
 109 };
 110 
 111 #ifndef PRODUCT
 112 void ParmNode::dump_spec(outputStream *st) const {
 113   if( _con < TypeFunc::Parms ) {
 114     st->print(names[_con]);
 115   } else {
 116     st->print("Parm%d: ",_con-TypeFunc::Parms);
 117     // Verbose and WizardMode dump bottom_type for all nodes
 118     if( !Verbose && !WizardMode )   bottom_type()->dump_on(st);
 119   }
 120 }
 121 #endif
 122 
 123 uint ParmNode::ideal_reg() const {
 124   switch( _con ) {
 125   case TypeFunc::Control  : // fall through
 126   case TypeFunc::I_O      : // fall through
 127   case TypeFunc::Memory   : return 0;
 128   case TypeFunc::FramePtr : // fall through
 129   case TypeFunc::ReturnAdr: return Op_RegP;
 130   default                 : assert( _con > TypeFunc::Parms, "" );
 131     // fall through
 132   case TypeFunc::Parms    : {
 133     // Type of argument being passed
 134     const Type *t = in(0)->as_Start()->_domain->field_at(_con);
 135     return t->ideal_reg();
 136   }
 137   }
 138   ShouldNotReachHere();
 139   return 0;
 140 }
 141 
 142 //=============================================================================
 143 ReturnNode::ReturnNode(uint edges, Node *cntrl, Node *i_o, Node *memory, Node *frameptr, Node *retadr ) : Node(edges) {
 144   init_req(TypeFunc::Control,cntrl);
 145   init_req(TypeFunc::I_O,i_o);
 146   init_req(TypeFunc::Memory,memory);
 147   init_req(TypeFunc::FramePtr,frameptr);
 148   init_req(TypeFunc::ReturnAdr,retadr);
 149 }
 150 
 151 Node *ReturnNode::Ideal(PhaseGVN *phase, bool can_reshape){
 152   return remove_dead_region(phase, can_reshape) ? this : NULL;
 153 }
 154 
 155 const Type *ReturnNode::Value( PhaseTransform *phase ) const {
 156   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
 157     ? Type::TOP
 158     : Type::BOTTOM;
 159 }
 160 
 161 // Do we Match on this edge index or not?  No edges on return nodes
 162 uint ReturnNode::match_edge(uint idx) const {
 163   return 0;
 164 }
 165 
 166 
 167 #ifndef PRODUCT
 168 void ReturnNode::dump_req(outputStream *st) const {
 169   // Dump the required inputs, enclosed in '(' and ')'
 170   uint i;                       // Exit value of loop
 171   for (i = 0; i < req(); i++) {    // For all required inputs
 172     if (i == TypeFunc::Parms) st->print("returns");
 173     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 174     else st->print("_ ");
 175   }
 176 }
 177 #endif
 178 
 179 //=============================================================================
 180 RethrowNode::RethrowNode(
 181   Node* cntrl,
 182   Node* i_o,
 183   Node* memory,
 184   Node* frameptr,
 185   Node* ret_adr,
 186   Node* exception
 187 ) : Node(TypeFunc::Parms + 1) {
 188   init_req(TypeFunc::Control  , cntrl    );
 189   init_req(TypeFunc::I_O      , i_o      );
 190   init_req(TypeFunc::Memory   , memory   );
 191   init_req(TypeFunc::FramePtr , frameptr );
 192   init_req(TypeFunc::ReturnAdr, ret_adr);
 193   init_req(TypeFunc::Parms    , exception);
 194 }
 195 
 196 Node *RethrowNode::Ideal(PhaseGVN *phase, bool can_reshape){
 197   return remove_dead_region(phase, can_reshape) ? this : NULL;
 198 }
 199 
 200 const Type *RethrowNode::Value( PhaseTransform *phase ) const {
 201   return (phase->type(in(TypeFunc::Control)) == Type::TOP)
 202     ? Type::TOP
 203     : Type::BOTTOM;
 204 }
 205 
 206 uint RethrowNode::match_edge(uint idx) const {
 207   return 0;
 208 }
 209 
 210 #ifndef PRODUCT
 211 void RethrowNode::dump_req(outputStream *st) const {
 212   // Dump the required inputs, enclosed in '(' and ')'
 213   uint i;                       // Exit value of loop
 214   for (i = 0; i < req(); i++) {    // For all required inputs
 215     if (i == TypeFunc::Parms) st->print("exception");
 216     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 217     else st->print("_ ");
 218   }
 219 }
 220 #endif
 221 
 222 //=============================================================================
 223 // Do we Match on this edge index or not?  Match only target address & method
 224 uint TailCallNode::match_edge(uint idx) const {
 225   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 226 }
 227 
 228 //=============================================================================
 229 // Do we Match on this edge index or not?  Match only target address & oop
 230 uint TailJumpNode::match_edge(uint idx) const {
 231   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 232 }
 233 
 234 //=============================================================================
 235 JVMState::JVMState(ciMethod* method, JVMState* caller) :
 236   _method(method) {
 237   assert(method != NULL, "must be valid call site");
 238   _reexecute = Reexecute_Undefined;
 239   debug_only(_bci = -99);  // random garbage value
 240   debug_only(_map = (SafePointNode*)-1);
 241   _caller = caller;
 242   _depth  = 1 + (caller == NULL ? 0 : caller->depth());
 243   _locoff = TypeFunc::Parms;
 244   _stkoff = _locoff + _method->max_locals();
 245   _monoff = _stkoff + _method->max_stack();
 246   _scloff = _monoff;
 247   _endoff = _monoff;
 248   _sp = 0;
 249 }
 250 JVMState::JVMState(int stack_size) :
 251   _method(NULL) {
 252   _bci = InvocationEntryBci;
 253   _reexecute = Reexecute_Undefined;
 254   debug_only(_map = (SafePointNode*)-1);
 255   _caller = NULL;
 256   _depth  = 1;
 257   _locoff = TypeFunc::Parms;
 258   _stkoff = _locoff;
 259   _monoff = _stkoff + stack_size;
 260   _scloff = _monoff;
 261   _endoff = _monoff;
 262   _sp = 0;
 263 }
 264 
 265 //--------------------------------of_depth-------------------------------------
 266 JVMState* JVMState::of_depth(int d) const {
 267   const JVMState* jvmp = this;
 268   assert(0 < d && (uint)d <= depth(), "oob");
 269   for (int skip = depth() - d; skip > 0; skip--) {
 270     jvmp = jvmp->caller();
 271   }
 272   assert(jvmp->depth() == (uint)d, "found the right one");
 273   return (JVMState*)jvmp;
 274 }
 275 
 276 //-----------------------------same_calls_as-----------------------------------
 277 bool JVMState::same_calls_as(const JVMState* that) const {
 278   if (this == that)                    return true;
 279   if (this->depth() != that->depth())  return false;
 280   const JVMState* p = this;
 281   const JVMState* q = that;
 282   for (;;) {
 283     if (p->_method != q->_method)    return false;
 284     if (p->_method == NULL)          return true;   // bci is irrelevant
 285     if (p->_bci    != q->_bci)       return false;
 286     if (p->_reexecute != q->_reexecute)  return false;
 287     p = p->caller();
 288     q = q->caller();
 289     if (p == q)                      return true;
 290     assert(p != NULL && q != NULL, "depth check ensures we don't run off end");
 291   }
 292 }
 293 
 294 //------------------------------debug_start------------------------------------
 295 uint JVMState::debug_start()  const {
 296   debug_only(JVMState* jvmroot = of_depth(1));
 297   assert(jvmroot->locoff() <= this->locoff(), "youngest JVMState must be last");
 298   return of_depth(1)->locoff();
 299 }
 300 
 301 //-------------------------------debug_end-------------------------------------
 302 uint JVMState::debug_end() const {
 303   debug_only(JVMState* jvmroot = of_depth(1));
 304   assert(jvmroot->endoff() <= this->endoff(), "youngest JVMState must be last");
 305   return endoff();
 306 }
 307 
 308 //------------------------------debug_depth------------------------------------
 309 uint JVMState::debug_depth() const {
 310   uint total = 0;
 311   for (const JVMState* jvmp = this; jvmp != NULL; jvmp = jvmp->caller()) {
 312     total += jvmp->debug_size();
 313   }
 314   return total;
 315 }
 316 
 317 #ifndef PRODUCT
 318 
 319 //------------------------------format_helper----------------------------------
 320 // Given an allocation (a Chaitin object) and a Node decide if the Node carries
 321 // any defined value or not.  If it does, print out the register or constant.
 322 static void format_helper( PhaseRegAlloc *regalloc, outputStream* st, Node *n, const char *msg, uint i, GrowableArray<SafePointScalarObjectNode*> *scobjs ) {
 323   if (n == NULL) { st->print(" NULL"); return; }
 324   if (n->is_SafePointScalarObject()) {
 325     // Scalar replacement.
 326     SafePointScalarObjectNode* spobj = n->as_SafePointScalarObject();
 327     scobjs->append_if_missing(spobj);
 328     int sco_n = scobjs->find(spobj);
 329     assert(sco_n >= 0, "");
 330     st->print(" %s%d]=#ScObj" INT32_FORMAT, msg, i, sco_n);
 331     return;
 332   }
 333   if (regalloc->node_regs_max_index() > 0 &&
 334       OptoReg::is_valid(regalloc->get_reg_first(n))) { // Check for undefined
 335     char buf[50];
 336     regalloc->dump_register(n,buf);
 337     st->print(" %s%d]=%s",msg,i,buf);
 338   } else {                      // No register, but might be constant
 339     const Type *t = n->bottom_type();
 340     switch (t->base()) {
 341     case Type::Int:
 342       st->print(" %s%d]=#"INT32_FORMAT,msg,i,t->is_int()->get_con());
 343       break;
 344     case Type::AnyPtr:
 345       assert( t == TypePtr::NULL_PTR || n->in_dump(), "" );
 346       st->print(" %s%d]=#NULL",msg,i);
 347       break;
 348     case Type::AryPtr:
 349     case Type::InstPtr:
 350       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->isa_oopptr()->const_oop());
 351       break;
 352     case Type::KlassPtr:
 353       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_klassptr()->klass());
 354       break;
 355     case Type::MetadataPtr:
 356       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_metadataptr()->metadata());
 357       break;
 358     case Type::NarrowOop:
 359       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_oopptr()->const_oop());
 360       break;
 361     case Type::RawPtr:
 362       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,t->is_rawptr());
 363       break;
 364     case Type::DoubleCon:
 365       st->print(" %s%d]=#%fD",msg,i,t->is_double_constant()->_d);
 366       break;
 367     case Type::FloatCon:
 368       st->print(" %s%d]=#%fF",msg,i,t->is_float_constant()->_f);
 369       break;
 370     case Type::Long:
 371       st->print(" %s%d]=#"INT64_FORMAT,msg,i,t->is_long()->get_con());
 372       break;
 373     case Type::Half:
 374     case Type::Top:
 375       st->print(" %s%d]=_",msg,i);
 376       break;
 377     default: ShouldNotReachHere();
 378     }
 379   }
 380 }
 381 
 382 //------------------------------format-----------------------------------------
 383 void JVMState::format(PhaseRegAlloc *regalloc, const Node *n, outputStream* st) const {
 384   st->print("        #");
 385   if (_method) {
 386     _method->print_short_name(st);
 387     st->print(" @ bci:%d ",_bci);
 388   } else {
 389     st->print_cr(" runtime stub ");
 390     return;
 391   }
 392   if (n->is_MachSafePoint()) {
 393     GrowableArray<SafePointScalarObjectNode*> scobjs;
 394     MachSafePointNode *mcall = n->as_MachSafePoint();
 395     uint i;
 396     // Print locals
 397     for (i = 0; i < (uint)loc_size(); i++)
 398       format_helper(regalloc, st, mcall->local(this, i), "L[", i, &scobjs);
 399     // Print stack
 400     for (i = 0; i < (uint)stk_size(); i++) {
 401       if ((uint)(_stkoff + i) >= mcall->len())
 402         st->print(" oob ");
 403       else
 404        format_helper(regalloc, st, mcall->stack(this, i), "STK[", i, &scobjs);
 405     }
 406     for (i = 0; (int)i < nof_monitors(); i++) {
 407       Node *box = mcall->monitor_box(this, i);
 408       Node *obj = mcall->monitor_obj(this, i);
 409       if (regalloc->node_regs_max_index() > 0 &&
 410           OptoReg::is_valid(regalloc->get_reg_first(box))) {
 411         box = BoxLockNode::box_node(box);
 412         format_helper(regalloc, st, box, "MON-BOX[", i, &scobjs);
 413       } else {
 414         OptoReg::Name box_reg = BoxLockNode::reg(box);
 415         st->print(" MON-BOX%d=%s+%d",
 416                    i,
 417                    OptoReg::regname(OptoReg::c_frame_pointer),
 418                    regalloc->reg2offset(box_reg));
 419       }
 420       const char* obj_msg = "MON-OBJ[";
 421       if (EliminateLocks) {
 422         if (BoxLockNode::box_node(box)->is_eliminated())
 423           obj_msg = "MON-OBJ(LOCK ELIMINATED)[";
 424       }
 425       format_helper(regalloc, st, obj, obj_msg, i, &scobjs);
 426     }
 427 
 428     for (i = 0; i < (uint)scobjs.length(); i++) {
 429       // Scalar replaced objects.
 430       st->print_cr("");
 431       st->print("        # ScObj" INT32_FORMAT " ", i);
 432       SafePointScalarObjectNode* spobj = scobjs.at(i);
 433       ciKlass* cik = spobj->bottom_type()->is_oopptr()->klass();
 434       assert(cik->is_instance_klass() ||
 435              cik->is_array_klass(), "Not supported allocation.");
 436       ciInstanceKlass *iklass = NULL;
 437       if (cik->is_instance_klass()) {
 438         cik->print_name_on(st);
 439         iklass = cik->as_instance_klass();
 440       } else if (cik->is_type_array_klass()) {
 441         cik->as_array_klass()->base_element_type()->print_name_on(st);
 442         st->print("[%d]", spobj->n_fields());
 443       } else if (cik->is_obj_array_klass()) {
 444         ciKlass* cie = cik->as_obj_array_klass()->base_element_klass();
 445         if (cie->is_instance_klass()) {
 446           cie->print_name_on(st);
 447         } else if (cie->is_type_array_klass()) {
 448           cie->as_array_klass()->base_element_type()->print_name_on(st);
 449         } else {
 450           ShouldNotReachHere();
 451         }
 452         st->print("[%d]", spobj->n_fields());
 453         int ndim = cik->as_array_klass()->dimension() - 1;
 454         while (ndim-- > 0) {
 455           st->print("[]");
 456         }
 457       }
 458       st->print("={");
 459       uint nf = spobj->n_fields();
 460       if (nf > 0) {
 461         uint first_ind = spobj->first_index(mcall->jvms());
 462         Node* fld_node = mcall->in(first_ind);
 463         ciField* cifield;
 464         if (iklass != NULL) {
 465           st->print(" [");
 466           cifield = iklass->nonstatic_field_at(0);
 467           cifield->print_name_on(st);
 468           format_helper(regalloc, st, fld_node, ":", 0, &scobjs);
 469         } else {
 470           format_helper(regalloc, st, fld_node, "[", 0, &scobjs);
 471         }
 472         for (uint j = 1; j < nf; j++) {
 473           fld_node = mcall->in(first_ind+j);
 474           if (iklass != NULL) {
 475             st->print(", [");
 476             cifield = iklass->nonstatic_field_at(j);
 477             cifield->print_name_on(st);
 478             format_helper(regalloc, st, fld_node, ":", j, &scobjs);
 479           } else {
 480             format_helper(regalloc, st, fld_node, ", [", j, &scobjs);
 481           }
 482         }
 483       }
 484       st->print(" }");
 485     }
 486   }
 487   st->print_cr("");
 488   if (caller() != NULL) caller()->format(regalloc, n, st);
 489 }
 490 
 491 
 492 void JVMState::dump_spec(outputStream *st) const {
 493   if (_method != NULL) {
 494     bool printed = false;
 495     if (!Verbose) {
 496       // The JVMS dumps make really, really long lines.
 497       // Take out the most boring parts, which are the package prefixes.
 498       char buf[500];
 499       stringStream namest(buf, sizeof(buf));
 500       _method->print_short_name(&namest);
 501       if (namest.count() < sizeof(buf)) {
 502         const char* name = namest.base();
 503         if (name[0] == ' ')  ++name;
 504         const char* endcn = strchr(name, ':');  // end of class name
 505         if (endcn == NULL)  endcn = strchr(name, '(');
 506         if (endcn == NULL)  endcn = name + strlen(name);
 507         while (endcn > name && endcn[-1] != '.' && endcn[-1] != '/')
 508           --endcn;
 509         st->print(" %s", endcn);
 510         printed = true;
 511       }
 512     }
 513     if (!printed)
 514       _method->print_short_name(st);
 515     st->print(" @ bci:%d",_bci);
 516     if(_reexecute == Reexecute_True)
 517       st->print(" reexecute");
 518   } else {
 519     st->print(" runtime stub");
 520   }
 521   if (caller() != NULL)  caller()->dump_spec(st);
 522 }
 523 
 524 
 525 void JVMState::dump_on(outputStream* st) const {
 526   bool print_map = _map && !((uintptr_t)_map & 1) &&
 527                   ((caller() == NULL) || (caller()->map() != _map));
 528   if (print_map) {
 529     if (_map->len() > _map->req()) {  // _map->has_exceptions()
 530       Node* ex = _map->in(_map->req());  // _map->next_exception()
 531       // skip the first one; it's already being printed
 532       while (ex != NULL && ex->len() > ex->req()) {
 533         ex = ex->in(ex->req());  // ex->next_exception()
 534         ex->dump(1);
 535       }
 536     }
 537     _map->dump(Verbose ? 2 : 1);
 538   }
 539   if (caller() != NULL) {
 540     caller()->dump_on(st);
 541   }
 542   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=",
 543              depth(), locoff(), stkoff(), argoff(), monoff(), scloff(), endoff(), monitor_depth(), sp(), bci(), should_reexecute()?"true":"false");
 544   if (_method == NULL) {
 545     st->print_cr("(none)");
 546   } else {
 547     _method->print_name(st);
 548     st->cr();
 549     if (bci() >= 0 && bci() < _method->code_size()) {
 550       st->print("    bc: ");
 551       _method->print_codes_on(bci(), bci()+1, st);
 552     }
 553   }
 554 }
 555 
 556 // Extra way to dump a jvms from the debugger,
 557 // to avoid a bug with C++ member function calls.
 558 void dump_jvms(JVMState* jvms) {
 559   jvms->dump();
 560 }
 561 #endif
 562 
 563 //--------------------------clone_shallow--------------------------------------
 564 JVMState* JVMState::clone_shallow(Compile* C) const {
 565   JVMState* n = has_method() ? new (C) JVMState(_method, _caller) : new (C) JVMState(0);
 566   n->set_bci(_bci);
 567   n->_reexecute = _reexecute;
 568   n->set_locoff(_locoff);
 569   n->set_stkoff(_stkoff);
 570   n->set_monoff(_monoff);
 571   n->set_scloff(_scloff);
 572   n->set_endoff(_endoff);
 573   n->set_sp(_sp);
 574   n->set_map(_map);
 575   return n;
 576 }
 577 
 578 //---------------------------clone_deep----------------------------------------
 579 JVMState* JVMState::clone_deep(Compile* C) const {
 580   JVMState* n = clone_shallow(C);
 581   for (JVMState* p = n; p->_caller != NULL; p = p->_caller) {
 582     p->_caller = p->_caller->clone_shallow(C);
 583   }
 584   assert(n->depth() == depth(), "sanity");
 585   assert(n->debug_depth() == debug_depth(), "sanity");
 586   return n;
 587 }
 588 
 589 /**
 590  * Reset map for all callers
 591  */
 592 void JVMState::set_map_deep(SafePointNode* map) {
 593   for (JVMState* p = this; p->_caller != NULL; p = p->_caller) {
 594     p->set_map(map);
 595   }
 596 }
 597 
 598 // Adapt offsets in in-array after adding or removing an edge.
 599 // Prerequisite is that the JVMState is used by only one node.
 600 void JVMState::adapt_position(int delta) {
 601   for (JVMState* jvms = this; jvms != NULL; jvms = jvms->caller()) {
 602     jvms->set_locoff(jvms->locoff() + delta);
 603     jvms->set_stkoff(jvms->stkoff() + delta);
 604     jvms->set_monoff(jvms->monoff() + delta);
 605     jvms->set_scloff(jvms->scloff() + delta);
 606     jvms->set_endoff(jvms->endoff() + delta);
 607   }
 608 }
 609 
 610 //=============================================================================
 611 uint CallNode::cmp( const Node &n ) const
 612 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }
 613 #ifndef PRODUCT
 614 void CallNode::dump_req(outputStream *st) const {
 615   // Dump the required inputs, enclosed in '(' and ')'
 616   uint i;                       // Exit value of loop
 617   for (i = 0; i < req(); i++) {    // For all required inputs
 618     if (i == TypeFunc::Parms) st->print("(");
 619     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 620     else st->print("_ ");
 621   }
 622   st->print(")");
 623 }
 624 
 625 void CallNode::dump_spec(outputStream *st) const {
 626   st->print(" ");
 627   tf()->dump_on(st);
 628   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);
 629   if (jvms() != NULL)  jvms()->dump_spec(st);
 630 }
 631 #endif
 632 
 633 const Type *CallNode::bottom_type() const { return tf()->range(); }
 634 const Type *CallNode::Value(PhaseTransform *phase) const {
 635   if (phase->type(in(0)) == Type::TOP)  return Type::TOP;
 636   return tf()->range();
 637 }
 638 
 639 //------------------------------calling_convention-----------------------------
 640 void CallNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 641   // Use the standard compiler calling convention
 642   Matcher::calling_convention( sig_bt, parm_regs, argcnt, true );
 643 }
 644 
 645 
 646 //------------------------------match------------------------------------------
 647 // Construct projections for control, I/O, memory-fields, ..., and
 648 // return result(s) along with their RegMask info
 649 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {
 650   switch (proj->_con) {
 651   case TypeFunc::Control:
 652   case TypeFunc::I_O:
 653   case TypeFunc::Memory:
 654     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
 655 
 656   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns
 657     assert(tf()->_range->field_at(TypeFunc::Parms+1) == Type::HALF, "");
 658     // 2nd half of doubles and longs
 659     return new (match->C) MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);
 660 
 661   case TypeFunc::Parms: {       // Normal returns
 662     uint ideal_reg = tf()->range()->field_at(TypeFunc::Parms)->ideal_reg();
 663     OptoRegPair regs = is_CallRuntime()
 664       ? match->c_return_value(ideal_reg,true)  // Calls into C runtime
 665       : match->  return_value(ideal_reg,true); // Calls into compiled Java code
 666     RegMask rm = RegMask(regs.first());
 667     if( OptoReg::is_valid(regs.second()) )
 668       rm.Insert( regs.second() );
 669     return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);
 670   }
 671 
 672   case TypeFunc::ReturnAdr:
 673   case TypeFunc::FramePtr:
 674   default:
 675     ShouldNotReachHere();
 676   }
 677   return NULL;
 678 }
 679 
 680 // Do we Match on this edge index or not?  Match no edges
 681 uint CallNode::match_edge(uint idx) const {
 682   return 0;
 683 }
 684 
 685 //
 686 // Determine whether the call could modify the field of the specified
 687 // instance at the specified offset.
 688 //
 689 bool CallNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 690   assert((t_oop != NULL), "sanity");
 691   if (t_oop->is_known_instance()) {
 692     // The instance_id is set only for scalar-replaceable allocations which
 693     // are not passed as arguments according to Escape Analysis.
 694     return false;
 695   }
 696   if (t_oop->is_ptr_to_boxed_value()) {
 697     ciKlass* boxing_klass = t_oop->klass();
 698     if (is_CallStaticJava() && as_CallStaticJava()->is_boxing_method()) {
 699       // Skip unrelated boxing methods.
 700       Node* proj = proj_out(TypeFunc::Parms);
 701       if ((proj == NULL) || (phase->type(proj)->is_instptr()->klass() != boxing_klass)) {
 702         return false;
 703       }
 704     }
 705     if (is_CallJava() && as_CallJava()->method() != NULL) {
 706       ciMethod* meth = as_CallJava()->method();
 707       if (meth->is_accessor()) {
 708         return false;
 709       }
 710       // May modify (by reflection) if an boxing object is passed
 711       // as argument or returned.
 712       if (returns_pointer() && (proj_out(TypeFunc::Parms) != NULL)) {
 713         Node* proj = proj_out(TypeFunc::Parms);
 714         const TypeInstPtr* inst_t = phase->type(proj)->isa_instptr();
 715         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 716                                  (inst_t->klass() == boxing_klass))) {
 717           return true;
 718         }
 719       }
 720       const TypeTuple* d = tf()->domain();
 721       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 722         const TypeInstPtr* inst_t = d->field_at(i)->isa_instptr();
 723         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 724                                  (inst_t->klass() == boxing_klass))) {
 725           return true;
 726         }
 727       }
 728       return false;
 729     }
 730   }
 731   return true;
 732 }
 733 
 734 // Does this call have a direct reference to n other than debug information?
 735 bool CallNode::has_non_debug_use(Node *n) {
 736   const TypeTuple * d = tf()->domain();
 737   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 738     Node *arg = in(i);
 739     if (arg == n) {
 740       return true;
 741     }
 742   }
 743   return false;
 744 }
 745 
 746 // Returns the unique CheckCastPP of a call
 747 // or 'this' if there are several CheckCastPP
 748 // or returns NULL if there is no one.
 749 Node *CallNode::result_cast() {
 750   Node *cast = NULL;
 751 
 752   Node *p = proj_out(TypeFunc::Parms);
 753   if (p == NULL)
 754     return NULL;
 755 
 756   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {
 757     Node *use = p->fast_out(i);
 758     if (use->is_CheckCastPP()) {
 759       if (cast != NULL) {
 760         return this;  // more than 1 CheckCastPP
 761       }
 762       cast = use;
 763     }
 764   }
 765   return cast;
 766 }
 767 
 768 
 769 void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj) {
 770   projs->fallthrough_proj      = NULL;
 771   projs->fallthrough_catchproj = NULL;
 772   projs->fallthrough_ioproj    = NULL;
 773   projs->catchall_ioproj       = NULL;
 774   projs->catchall_catchproj    = NULL;
 775   projs->fallthrough_memproj   = NULL;
 776   projs->catchall_memproj      = NULL;
 777   projs->resproj               = NULL;
 778   projs->exobj                 = NULL;
 779 
 780   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 781     ProjNode *pn = fast_out(i)->as_Proj();
 782     if (pn->outcnt() == 0) continue;
 783     switch (pn->_con) {
 784     case TypeFunc::Control:
 785       {
 786         // For Control (fallthrough) and I_O (catch_all_index) we have CatchProj -> Catch -> Proj
 787         projs->fallthrough_proj = pn;
 788         DUIterator_Fast jmax, j = pn->fast_outs(jmax);
 789         const Node *cn = pn->fast_out(j);
 790         if (cn->is_Catch()) {
 791           ProjNode *cpn = NULL;
 792           for (DUIterator_Fast kmax, k = cn->fast_outs(kmax); k < kmax; k++) {
 793             cpn = cn->fast_out(k)->as_Proj();
 794             assert(cpn->is_CatchProj(), "must be a CatchProjNode");
 795             if (cpn->_con == CatchProjNode::fall_through_index)
 796               projs->fallthrough_catchproj = cpn;
 797             else {
 798               assert(cpn->_con == CatchProjNode::catch_all_index, "must be correct index.");
 799               projs->catchall_catchproj = cpn;
 800             }
 801           }
 802         }
 803         break;
 804       }
 805     case TypeFunc::I_O:
 806       if (pn->_is_io_use)
 807         projs->catchall_ioproj = pn;
 808       else
 809         projs->fallthrough_ioproj = pn;
 810       for (DUIterator j = pn->outs(); pn->has_out(j); j++) {
 811         Node* e = pn->out(j);
 812         if (e->Opcode() == Op_CreateEx && e->in(0)->is_CatchProj() && e->outcnt() > 0) {
 813           assert(projs->exobj == NULL, "only one");
 814           projs->exobj = e;
 815         }
 816       }
 817       break;
 818     case TypeFunc::Memory:
 819       if (pn->_is_io_use)
 820         projs->catchall_memproj = pn;
 821       else
 822         projs->fallthrough_memproj = pn;
 823       break;
 824     case TypeFunc::Parms:
 825       projs->resproj = pn;
 826       break;
 827     default:
 828       assert(false, "unexpected projection from allocation node.");
 829     }
 830   }
 831 
 832   // The resproj may not exist because the result couuld be ignored
 833   // and the exception object may not exist if an exception handler
 834   // swallows the exception but all the other must exist and be found.
 835   assert(projs->fallthrough_proj      != NULL, "must be found");
 836   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_catchproj != NULL, "must be found");
 837   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_memproj   != NULL, "must be found");
 838   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_ioproj    != NULL, "must be found");
 839   assert(Compile::current()->inlining_incrementally() || projs->catchall_catchproj    != NULL, "must be found");
 840   if (separate_io_proj) {
 841     assert(Compile::current()->inlining_incrementally() || projs->catchall_memproj    != NULL, "must be found");
 842     assert(Compile::current()->inlining_incrementally() || projs->catchall_ioproj     != NULL, "must be found");
 843   }
 844 }
 845 
 846 Node *CallNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 847   CallGenerator* cg = generator();
 848   if (can_reshape && cg != NULL && cg->is_mh_late_inline() && !cg->already_attempted()) {
 849     // Check whether this MH handle call becomes a candidate for inlining
 850     ciMethod* callee = cg->method();
 851     vmIntrinsics::ID iid = callee->intrinsic_id();
 852     if (iid == vmIntrinsics::_invokeBasic) {
 853       if (in(TypeFunc::Parms)->Opcode() == Op_ConP) {
 854         phase->C->prepend_late_inline(cg);
 855         set_generator(NULL);
 856       }
 857     } else {
 858       assert(callee->has_member_arg(), "wrong type of call?");
 859       if (in(TypeFunc::Parms + callee->arg_size() - 1)->Opcode() == Op_ConP) {
 860         phase->C->prepend_late_inline(cg);
 861         set_generator(NULL);
 862       }
 863     }
 864   }
 865   return SafePointNode::Ideal(phase, can_reshape);
 866 }
 867 
 868 
 869 //=============================================================================
 870 uint CallJavaNode::size_of() const { return sizeof(*this); }
 871 uint CallJavaNode::cmp( const Node &n ) const {
 872   CallJavaNode &call = (CallJavaNode&)n;
 873   return CallNode::cmp(call) && _method == call._method;
 874 }
 875 #ifndef PRODUCT
 876 void CallJavaNode::dump_spec(outputStream *st) const {
 877   if( _method ) _method->print_short_name(st);
 878   CallNode::dump_spec(st);
 879 }
 880 #endif
 881 
 882 //=============================================================================
 883 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }
 884 uint CallStaticJavaNode::cmp( const Node &n ) const {
 885   CallStaticJavaNode &call = (CallStaticJavaNode&)n;
 886   return CallJavaNode::cmp(call);
 887 }
 888 
 889 //----------------------------uncommon_trap_request----------------------------
 890 // If this is an uncommon trap, return the request code, else zero.
 891 int CallStaticJavaNode::uncommon_trap_request() const {
 892   if (_name != NULL && !strcmp(_name, "uncommon_trap")) {
 893     return extract_uncommon_trap_request(this);
 894   }
 895   return 0;
 896 }
 897 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {
 898 #ifndef PRODUCT
 899   if (!(call->req() > TypeFunc::Parms &&
 900         call->in(TypeFunc::Parms) != NULL &&
 901         call->in(TypeFunc::Parms)->is_Con())) {
 902     assert(in_dump() != 0, "OK if dumping");
 903     tty->print("[bad uncommon trap]");
 904     return 0;
 905   }
 906 #endif
 907   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();
 908 }
 909 
 910 #ifndef PRODUCT
 911 void CallStaticJavaNode::dump_spec(outputStream *st) const {
 912   st->print("# Static ");
 913   if (_name != NULL) {
 914     st->print("%s", _name);
 915     int trap_req = uncommon_trap_request();
 916     if (trap_req != 0) {
 917       char buf[100];
 918       st->print("(%s)",
 919                  Deoptimization::format_trap_request(buf, sizeof(buf),
 920                                                      trap_req));
 921     }
 922     st->print(" ");
 923   }
 924   CallJavaNode::dump_spec(st);
 925 }
 926 #endif
 927 
 928 //=============================================================================
 929 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }
 930 uint CallDynamicJavaNode::cmp( const Node &n ) const {
 931   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;
 932   return CallJavaNode::cmp(call);
 933 }
 934 #ifndef PRODUCT
 935 void CallDynamicJavaNode::dump_spec(outputStream *st) const {
 936   st->print("# Dynamic ");
 937   CallJavaNode::dump_spec(st);
 938 }
 939 #endif
 940 
 941 //=============================================================================
 942 uint CallRuntimeNode::size_of() const { return sizeof(*this); }
 943 uint CallRuntimeNode::cmp( const Node &n ) const {
 944   CallRuntimeNode &call = (CallRuntimeNode&)n;
 945   return CallNode::cmp(call) && !strcmp(_name,call._name);
 946 }
 947 #ifndef PRODUCT
 948 void CallRuntimeNode::dump_spec(outputStream *st) const {
 949   st->print("# ");
 950   st->print(_name);
 951   CallNode::dump_spec(st);
 952 }
 953 #endif
 954 
 955 //------------------------------calling_convention-----------------------------
 956 void CallRuntimeNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 957   Matcher::c_calling_convention( sig_bt, parm_regs, argcnt );
 958 }
 959 
 960 //=============================================================================
 961 //------------------------------calling_convention-----------------------------
 962 
 963 
 964 //=============================================================================
 965 #ifndef PRODUCT
 966 void CallLeafNode::dump_spec(outputStream *st) const {
 967   st->print("# ");
 968   st->print(_name);
 969   CallNode::dump_spec(st);
 970 }
 971 #endif
 972 
 973 //=============================================================================
 974 
 975 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {
 976   assert(verify_jvms(jvms), "jvms must match");
 977   int loc = jvms->locoff() + idx;
 978   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {
 979     // If current local idx is top then local idx - 1 could
 980     // be a long/double that needs to be killed since top could
 981     // represent the 2nd half ofthe long/double.
 982     uint ideal = in(loc -1)->ideal_reg();
 983     if (ideal == Op_RegD || ideal == Op_RegL) {
 984       // set other (low index) half to top
 985       set_req(loc - 1, in(loc));
 986     }
 987   }
 988   set_req(loc, c);
 989 }
 990 
 991 uint SafePointNode::size_of() const { return sizeof(*this); }
 992 uint SafePointNode::cmp( const Node &n ) const {
 993   return (&n == this);          // Always fail except on self
 994 }
 995 
 996 //-------------------------set_next_exception----------------------------------
 997 void SafePointNode::set_next_exception(SafePointNode* n) {
 998   assert(n == NULL || n->Opcode() == Op_SafePoint, "correct value for next_exception");
 999   if (len() == req()) {
1000     if (n != NULL)  add_prec(n);
1001   } else {
1002     set_prec(req(), n);
1003   }
1004 }
1005 
1006 
1007 //----------------------------next_exception-----------------------------------
1008 SafePointNode* SafePointNode::next_exception() const {
1009   if (len() == req()) {
1010     return NULL;
1011   } else {
1012     Node* n = in(req());
1013     assert(n == NULL || n->Opcode() == Op_SafePoint, "no other uses of prec edges");
1014     return (SafePointNode*) n;
1015   }
1016 }
1017 
1018 
1019 //------------------------------Ideal------------------------------------------
1020 // Skip over any collapsed Regions
1021 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1022   return remove_dead_region(phase, can_reshape) ? this : NULL;
1023 }
1024 
1025 //------------------------------Identity---------------------------------------
1026 // Remove obviously duplicate safepoints
1027 Node *SafePointNode::Identity( PhaseTransform *phase ) {
1028 
1029   // If you have back to back safepoints, remove one
1030   if( in(TypeFunc::Control)->is_SafePoint() )
1031     return in(TypeFunc::Control);
1032 
1033   if( in(0)->is_Proj() ) {
1034     Node *n0 = in(0)->in(0);
1035     // Check if he is a call projection (except Leaf Call)
1036     if( n0->is_Catch() ) {
1037       n0 = n0->in(0)->in(0);
1038       assert( n0->is_Call(), "expect a call here" );
1039     }
1040     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {
1041       // Useless Safepoint, so remove it
1042       return in(TypeFunc::Control);
1043     }
1044   }
1045 
1046   return this;
1047 }
1048 
1049 //------------------------------Value------------------------------------------
1050 const Type *SafePointNode::Value( PhaseTransform *phase ) const {
1051   if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
1052   if( phase->eqv( in(0), this ) ) return Type::TOP; // Dead infinite loop
1053   return Type::CONTROL;
1054 }
1055 
1056 #ifndef PRODUCT
1057 void SafePointNode::dump_spec(outputStream *st) const {
1058   st->print(" SafePoint ");
1059 }
1060 #endif
1061 
1062 const RegMask &SafePointNode::in_RegMask(uint idx) const {
1063   if( idx < TypeFunc::Parms ) return RegMask::Empty;
1064   // Values outside the domain represent debug info
1065   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1066 }
1067 const RegMask &SafePointNode::out_RegMask() const {
1068   return RegMask::Empty;
1069 }
1070 
1071 
1072 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {
1073   assert((int)grow_by > 0, "sanity");
1074   int monoff = jvms->monoff();
1075   int scloff = jvms->scloff();
1076   int endoff = jvms->endoff();
1077   assert(endoff == (int)req(), "no other states or debug info after me");
1078   Node* top = Compile::current()->top();
1079   for (uint i = 0; i < grow_by; i++) {
1080     ins_req(monoff, top);
1081   }
1082   jvms->set_monoff(monoff + grow_by);
1083   jvms->set_scloff(scloff + grow_by);
1084   jvms->set_endoff(endoff + grow_by);
1085 }
1086 
1087 void SafePointNode::push_monitor(const FastLockNode *lock) {
1088   // Add a LockNode, which points to both the original BoxLockNode (the
1089   // stack space for the monitor) and the Object being locked.
1090   const int MonitorEdges = 2;
1091   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1092   assert(req() == jvms()->endoff(), "correct sizing");
1093   int nextmon = jvms()->scloff();
1094   if (GenerateSynchronizationCode) {
1095     ins_req(nextmon,   lock->box_node());
1096     ins_req(nextmon+1, lock->obj_node());
1097   } else {
1098     Node* top = Compile::current()->top();
1099     ins_req(nextmon, top);
1100     ins_req(nextmon, top);
1101   }
1102   jvms()->set_scloff(nextmon + MonitorEdges);
1103   jvms()->set_endoff(req());
1104 }
1105 
1106 void SafePointNode::pop_monitor() {
1107   // Delete last monitor from debug info
1108   debug_only(int num_before_pop = jvms()->nof_monitors());
1109   const int MonitorEdges = 2;
1110   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1111   int scloff = jvms()->scloff();
1112   int endoff = jvms()->endoff();
1113   int new_scloff = scloff - MonitorEdges;
1114   int new_endoff = endoff - MonitorEdges;
1115   jvms()->set_scloff(new_scloff);
1116   jvms()->set_endoff(new_endoff);
1117   while (scloff > new_scloff)  del_req_ordered(--scloff);
1118   assert(jvms()->nof_monitors() == num_before_pop-1, "");
1119 }
1120 
1121 Node *SafePointNode::peek_monitor_box() const {
1122   int mon = jvms()->nof_monitors() - 1;
1123   assert(mon >= 0, "most have a monitor");
1124   return monitor_box(jvms(), mon);
1125 }
1126 
1127 Node *SafePointNode::peek_monitor_obj() const {
1128   int mon = jvms()->nof_monitors() - 1;
1129   assert(mon >= 0, "most have a monitor");
1130   return monitor_obj(jvms(), mon);
1131 }
1132 
1133 // Do we Match on this edge index or not?  Match no edges
1134 uint SafePointNode::match_edge(uint idx) const {
1135   if( !needs_polling_address_input() )
1136     return 0;
1137 
1138   return (TypeFunc::Parms == idx);
1139 }
1140 
1141 //==============  SafePointScalarObjectNode  ==============
1142 
1143 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp,
1144 #ifdef ASSERT
1145                                                      AllocateNode* alloc,
1146 #endif
1147                                                      uint first_index,
1148                                                      uint n_fields) :
1149   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
1150 #ifdef ASSERT
1151   _alloc(alloc),
1152 #endif
1153   _first_index(first_index),
1154   _n_fields(n_fields)
1155 {
1156   init_class_id(Class_SafePointScalarObject);
1157 }
1158 
1159 // Do not allow value-numbering for SafePointScalarObject node.
1160 uint SafePointScalarObjectNode::hash() const { return NO_HASH; }
1161 uint SafePointScalarObjectNode::cmp( const Node &n ) const {
1162   return (&n == this); // Always fail except on self
1163 }
1164 
1165 uint SafePointScalarObjectNode::ideal_reg() const {
1166   return 0; // No matching to machine instruction
1167 }
1168 
1169 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {
1170   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1171 }
1172 
1173 const RegMask &SafePointScalarObjectNode::out_RegMask() const {
1174   return RegMask::Empty;
1175 }
1176 
1177 uint SafePointScalarObjectNode::match_edge(uint idx) const {
1178   return 0;
1179 }
1180 
1181 SafePointScalarObjectNode*
1182 SafePointScalarObjectNode::clone(Dict* sosn_map) const {
1183   void* cached = (*sosn_map)[(void*)this];
1184   if (cached != NULL) {
1185     return (SafePointScalarObjectNode*)cached;
1186   }
1187   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();
1188   sosn_map->Insert((void*)this, (void*)res);
1189   return res;
1190 }
1191 
1192 
1193 #ifndef PRODUCT
1194 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {
1195   st->print(" # fields@[%d..%d]", first_index(),
1196              first_index() + n_fields() - 1);
1197 }
1198 
1199 #endif
1200 
1201 //=============================================================================
1202 uint AllocateNode::size_of() const { return sizeof(*this); }
1203 
1204 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,
1205                            Node *ctrl, Node *mem, Node *abio,
1206                            Node *size, Node *klass_node, Node *initial_test)
1207   : CallNode(atype, NULL, TypeRawPtr::BOTTOM)
1208 {
1209   init_class_id(Class_Allocate);
1210   init_flags(Flag_is_macro);
1211   _is_scalar_replaceable = false;
1212   _is_non_escaping = false;
1213   Node *topnode = C->top();
1214 
1215   init_req( TypeFunc::Control  , ctrl );
1216   init_req( TypeFunc::I_O      , abio );
1217   init_req( TypeFunc::Memory   , mem );
1218   init_req( TypeFunc::ReturnAdr, topnode );
1219   init_req( TypeFunc::FramePtr , topnode );
1220   init_req( AllocSize          , size);
1221   init_req( KlassNode          , klass_node);
1222   init_req( InitialTest        , initial_test);
1223   init_req( ALength            , topnode);
1224   C->add_macro_node(this);
1225 }
1226 
1227 //=============================================================================
1228 Node* AllocateArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1229   if (remove_dead_region(phase, can_reshape))  return this;
1230   // Don't bother trying to transform a dead node
1231   if (in(0) && in(0)->is_top())  return NULL;
1232 
1233   const Type* type = phase->type(Ideal_length());
1234   if (type->isa_int() && type->is_int()->_hi < 0) {
1235     if (can_reshape) {
1236       PhaseIterGVN *igvn = phase->is_IterGVN();
1237       // Unreachable fall through path (negative array length),
1238       // the allocation can only throw so disconnect it.
1239       Node* proj = proj_out(TypeFunc::Control);
1240       Node* catchproj = NULL;
1241       if (proj != NULL) {
1242         for (DUIterator_Fast imax, i = proj->fast_outs(imax); i < imax; i++) {
1243           Node *cn = proj->fast_out(i);
1244           if (cn->is_Catch()) {
1245             catchproj = cn->as_Multi()->proj_out(CatchProjNode::fall_through_index);
1246             break;
1247           }
1248         }
1249       }
1250       if (catchproj != NULL && catchproj->outcnt() > 0 &&
1251           (catchproj->outcnt() > 1 ||
1252            catchproj->unique_out()->Opcode() != Op_Halt)) {
1253         assert(catchproj->is_CatchProj(), "must be a CatchProjNode");
1254         Node* nproj = catchproj->clone();
1255         igvn->register_new_node_with_optimizer(nproj);
1256 
1257         Node *frame = new (phase->C) ParmNode( phase->C->start(), TypeFunc::FramePtr );
1258         frame = phase->transform(frame);
1259         // Halt & Catch Fire
1260         Node *halt = new (phase->C) HaltNode( nproj, frame );
1261         phase->C->root()->add_req(halt);
1262         phase->transform(halt);
1263 
1264         igvn->replace_node(catchproj, phase->C->top());
1265         return this;
1266       }
1267     } else {
1268       // Can't correct it during regular GVN so register for IGVN
1269       phase->C->record_for_igvn(this);
1270     }
1271   }
1272   return NULL;
1273 }
1274 
1275 // Retrieve the length from the AllocateArrayNode. Narrow the type with a
1276 // CastII, if appropriate.  If we are not allowed to create new nodes, and
1277 // a CastII is appropriate, return NULL.
1278 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseTransform *phase, bool allow_new_nodes) {
1279   Node *length = in(AllocateNode::ALength);
1280   assert(length != NULL, "length is not null");
1281 
1282   const TypeInt* length_type = phase->find_int_type(length);
1283   const TypeAryPtr* ary_type = oop_type->isa_aryptr();
1284 
1285   if (ary_type != NULL && length_type != NULL) {
1286     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);
1287     if (narrow_length_type != length_type) {
1288       // Assert one of:
1289       //   - the narrow_length is 0
1290       //   - the narrow_length is not wider than length
1291       assert(narrow_length_type == TypeInt::ZERO ||
1292              length_type->is_con() && narrow_length_type->is_con() &&
1293                 (narrow_length_type->_hi <= length_type->_lo) ||
1294              (narrow_length_type->_hi <= length_type->_hi &&
1295               narrow_length_type->_lo >= length_type->_lo),
1296              "narrow type must be narrower than length type");
1297 
1298       // Return NULL if new nodes are not allowed
1299       if (!allow_new_nodes) return NULL;
1300       // Create a cast which is control dependent on the initialization to
1301       // propagate the fact that the array length must be positive.
1302       length = new (phase->C) CastIINode(length, narrow_length_type);
1303       length->set_req(0, initialization()->proj_out(0));
1304     }
1305   }
1306 
1307   return length;
1308 }
1309 
1310 //=============================================================================
1311 uint LockNode::size_of() const { return sizeof(*this); }
1312 
1313 // Redundant lock elimination
1314 //
1315 // There are various patterns of locking where we release and
1316 // immediately reacquire a lock in a piece of code where no operations
1317 // occur in between that would be observable.  In those cases we can
1318 // skip releasing and reacquiring the lock without violating any
1319 // fairness requirements.  Doing this around a loop could cause a lock
1320 // to be held for a very long time so we concentrate on non-looping
1321 // control flow.  We also require that the operations are fully
1322 // redundant meaning that we don't introduce new lock operations on
1323 // some paths so to be able to eliminate it on others ala PRE.  This
1324 // would probably require some more extensive graph manipulation to
1325 // guarantee that the memory edges were all handled correctly.
1326 //
1327 // Assuming p is a simple predicate which can't trap in any way and s
1328 // is a synchronized method consider this code:
1329 //
1330 //   s();
1331 //   if (p)
1332 //     s();
1333 //   else
1334 //     s();
1335 //   s();
1336 //
1337 // 1. The unlocks of the first call to s can be eliminated if the
1338 // locks inside the then and else branches are eliminated.
1339 //
1340 // 2. The unlocks of the then and else branches can be eliminated if
1341 // the lock of the final call to s is eliminated.
1342 //
1343 // Either of these cases subsumes the simple case of sequential control flow
1344 //
1345 // Addtionally we can eliminate versions without the else case:
1346 //
1347 //   s();
1348 //   if (p)
1349 //     s();
1350 //   s();
1351 //
1352 // 3. In this case we eliminate the unlock of the first s, the lock
1353 // and unlock in the then case and the lock in the final s.
1354 //
1355 // Note also that in all these cases the then/else pieces don't have
1356 // to be trivial as long as they begin and end with synchronization
1357 // operations.
1358 //
1359 //   s();
1360 //   if (p)
1361 //     s();
1362 //     f();
1363 //     s();
1364 //   s();
1365 //
1366 // The code will work properly for this case, leaving in the unlock
1367 // before the call to f and the relock after it.
1368 //
1369 // A potentially interesting case which isn't handled here is when the
1370 // locking is partially redundant.
1371 //
1372 //   s();
1373 //   if (p)
1374 //     s();
1375 //
1376 // This could be eliminated putting unlocking on the else case and
1377 // eliminating the first unlock and the lock in the then side.
1378 // Alternatively the unlock could be moved out of the then side so it
1379 // was after the merge and the first unlock and second lock
1380 // eliminated.  This might require less manipulation of the memory
1381 // state to get correct.
1382 //
1383 // Additionally we might allow work between a unlock and lock before
1384 // giving up eliminating the locks.  The current code disallows any
1385 // conditional control flow between these operations.  A formulation
1386 // similar to partial redundancy elimination computing the
1387 // availability of unlocking and the anticipatability of locking at a
1388 // program point would allow detection of fully redundant locking with
1389 // some amount of work in between.  I'm not sure how often I really
1390 // think that would occur though.  Most of the cases I've seen
1391 // indicate it's likely non-trivial work would occur in between.
1392 // There may be other more complicated constructs where we could
1393 // eliminate locking but I haven't seen any others appear as hot or
1394 // interesting.
1395 //
1396 // Locking and unlocking have a canonical form in ideal that looks
1397 // roughly like this:
1398 //
1399 //              <obj>
1400 //                | \\------+
1401 //                |  \       \
1402 //                | BoxLock   \
1403 //                |  |   |     \
1404 //                |  |    \     \
1405 //                |  |   FastLock
1406 //                |  |   /
1407 //                |  |  /
1408 //                |  |  |
1409 //
1410 //               Lock
1411 //                |
1412 //            Proj #0
1413 //                |
1414 //            MembarAcquire
1415 //                |
1416 //            Proj #0
1417 //
1418 //            MembarRelease
1419 //                |
1420 //            Proj #0
1421 //                |
1422 //              Unlock
1423 //                |
1424 //            Proj #0
1425 //
1426 //
1427 // This code proceeds by processing Lock nodes during PhaseIterGVN
1428 // and searching back through its control for the proper code
1429 // patterns.  Once it finds a set of lock and unlock operations to
1430 // eliminate they are marked as eliminatable which causes the
1431 // expansion of the Lock and Unlock macro nodes to make the operation a NOP
1432 //
1433 //=============================================================================
1434 
1435 //
1436 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:
1437 //   - copy regions.  (These may not have been optimized away yet.)
1438 //   - eliminated locking nodes
1439 //
1440 static Node *next_control(Node *ctrl) {
1441   if (ctrl == NULL)
1442     return NULL;
1443   while (1) {
1444     if (ctrl->is_Region()) {
1445       RegionNode *r = ctrl->as_Region();
1446       Node *n = r->is_copy();
1447       if (n == NULL)
1448         break;  // hit a region, return it
1449       else
1450         ctrl = n;
1451     } else if (ctrl->is_Proj()) {
1452       Node *in0 = ctrl->in(0);
1453       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {
1454         ctrl = in0->in(0);
1455       } else {
1456         break;
1457       }
1458     } else {
1459       break; // found an interesting control
1460     }
1461   }
1462   return ctrl;
1463 }
1464 //
1465 // Given a control, see if it's the control projection of an Unlock which
1466 // operating on the same object as lock.
1467 //
1468 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,
1469                                             GrowableArray<AbstractLockNode*> &lock_ops) {
1470   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : NULL;
1471   if (ctrl_proj != NULL && ctrl_proj->_con == TypeFunc::Control) {
1472     Node *n = ctrl_proj->in(0);
1473     if (n != NULL && n->is_Unlock()) {
1474       UnlockNode *unlock = n->as_Unlock();
1475       if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1476           BoxLockNode::same_slot(lock->box_node(), unlock->box_node()) &&
1477           !unlock->is_eliminated()) {
1478         lock_ops.append(unlock);
1479         return true;
1480       }
1481     }
1482   }
1483   return false;
1484 }
1485 
1486 //
1487 // Find the lock matching an unlock.  Returns null if a safepoint
1488 // or complicated control is encountered first.
1489 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {
1490   LockNode *lock_result = NULL;
1491   // find the matching lock, or an intervening safepoint
1492   Node *ctrl = next_control(unlock->in(0));
1493   while (1) {
1494     assert(ctrl != NULL, "invalid control graph");
1495     assert(!ctrl->is_Start(), "missing lock for unlock");
1496     if (ctrl->is_top()) break;  // dead control path
1497     if (ctrl->is_Proj()) ctrl = ctrl->in(0);
1498     if (ctrl->is_SafePoint()) {
1499         break;  // found a safepoint (may be the lock we are searching for)
1500     } else if (ctrl->is_Region()) {
1501       // Check for a simple diamond pattern.  Punt on anything more complicated
1502       if (ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(2) != NULL) {
1503         Node *in1 = next_control(ctrl->in(1));
1504         Node *in2 = next_control(ctrl->in(2));
1505         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||
1506              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {
1507           ctrl = next_control(in1->in(0)->in(0));
1508         } else {
1509           break;
1510         }
1511       } else {
1512         break;
1513       }
1514     } else {
1515       ctrl = next_control(ctrl->in(0));  // keep searching
1516     }
1517   }
1518   if (ctrl->is_Lock()) {
1519     LockNode *lock = ctrl->as_Lock();
1520     if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1521         BoxLockNode::same_slot(lock->box_node(), unlock->box_node())) {
1522       lock_result = lock;
1523     }
1524   }
1525   return lock_result;
1526 }
1527 
1528 // This code corresponds to case 3 above.
1529 
1530 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,
1531                                                        GrowableArray<AbstractLockNode*> &lock_ops) {
1532   Node* if_node = node->in(0);
1533   bool  if_true = node->is_IfTrue();
1534 
1535   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {
1536     Node *lock_ctrl = next_control(if_node->in(0));
1537     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {
1538       Node* lock1_node = NULL;
1539       ProjNode* proj = if_node->as_If()->proj_out(!if_true);
1540       if (if_true) {
1541         if (proj->is_IfFalse() && proj->outcnt() == 1) {
1542           lock1_node = proj->unique_out();
1543         }
1544       } else {
1545         if (proj->is_IfTrue() && proj->outcnt() == 1) {
1546           lock1_node = proj->unique_out();
1547         }
1548       }
1549       if (lock1_node != NULL && lock1_node->is_Lock()) {
1550         LockNode *lock1 = lock1_node->as_Lock();
1551         if (lock->obj_node()->eqv_uncast(lock1->obj_node()) &&
1552             BoxLockNode::same_slot(lock->box_node(), lock1->box_node()) &&
1553             !lock1->is_eliminated()) {
1554           lock_ops.append(lock1);
1555           return true;
1556         }
1557       }
1558     }
1559   }
1560 
1561   lock_ops.trunc_to(0);
1562   return false;
1563 }
1564 
1565 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,
1566                                GrowableArray<AbstractLockNode*> &lock_ops) {
1567   // check each control merging at this point for a matching unlock.
1568   // in(0) should be self edge so skip it.
1569   for (int i = 1; i < (int)region->req(); i++) {
1570     Node *in_node = next_control(region->in(i));
1571     if (in_node != NULL) {
1572       if (find_matching_unlock(in_node, lock, lock_ops)) {
1573         // found a match so keep on checking.
1574         continue;
1575       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {
1576         continue;
1577       }
1578 
1579       // If we fall through to here then it was some kind of node we
1580       // don't understand or there wasn't a matching unlock, so give
1581       // up trying to merge locks.
1582       lock_ops.trunc_to(0);
1583       return false;
1584     }
1585   }
1586   return true;
1587 
1588 }
1589 
1590 #ifndef PRODUCT
1591 //
1592 // Create a counter which counts the number of times this lock is acquired
1593 //
1594 void AbstractLockNode::create_lock_counter(JVMState* state) {
1595   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);
1596 }
1597 
1598 void AbstractLockNode::set_eliminated_lock_counter() {
1599   if (_counter) {
1600     // Update the counter to indicate that this lock was eliminated.
1601     // The counter update code will stay around even though the
1602     // optimizer will eliminate the lock operation itself.
1603     _counter->set_tag(NamedCounter::EliminatedLockCounter);
1604   }
1605 }
1606 #endif
1607 
1608 //=============================================================================
1609 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1610 
1611   // perform any generic optimizations first (returns 'this' or NULL)
1612   Node *result = SafePointNode::Ideal(phase, can_reshape);
1613   if (result != NULL)  return result;
1614   // Don't bother trying to transform a dead node
1615   if (in(0) && in(0)->is_top())  return NULL;
1616 
1617   // Now see if we can optimize away this lock.  We don't actually
1618   // remove the locking here, we simply set the _eliminate flag which
1619   // prevents macro expansion from expanding the lock.  Since we don't
1620   // modify the graph, the value returned from this function is the
1621   // one computed above.
1622   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1623     //
1624     // If we are locking an unescaped object, the lock/unlock is unnecessary
1625     //
1626     ConnectionGraph *cgr = phase->C->congraph();
1627     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1628       assert(!is_eliminated() || is_coarsened(), "sanity");
1629       // The lock could be marked eliminated by lock coarsening
1630       // code during first IGVN before EA. Replace coarsened flag
1631       // to eliminate all associated locks/unlocks.
1632       this->set_non_esc_obj();
1633       return result;
1634     }
1635 
1636     //
1637     // Try lock coarsening
1638     //
1639     PhaseIterGVN* iter = phase->is_IterGVN();
1640     if (iter != NULL && !is_eliminated()) {
1641 
1642       GrowableArray<AbstractLockNode*>   lock_ops;
1643 
1644       Node *ctrl = next_control(in(0));
1645 
1646       // now search back for a matching Unlock
1647       if (find_matching_unlock(ctrl, this, lock_ops)) {
1648         // found an unlock directly preceding this lock.  This is the
1649         // case of single unlock directly control dependent on a
1650         // single lock which is the trivial version of case 1 or 2.
1651       } else if (ctrl->is_Region() ) {
1652         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {
1653         // found lock preceded by multiple unlocks along all paths
1654         // joining at this point which is case 3 in description above.
1655         }
1656       } else {
1657         // see if this lock comes from either half of an if and the
1658         // predecessors merges unlocks and the other half of the if
1659         // performs a lock.
1660         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {
1661           // found unlock splitting to an if with locks on both branches.
1662         }
1663       }
1664 
1665       if (lock_ops.length() > 0) {
1666         // add ourselves to the list of locks to be eliminated.
1667         lock_ops.append(this);
1668 
1669   #ifndef PRODUCT
1670         if (PrintEliminateLocks) {
1671           int locks = 0;
1672           int unlocks = 0;
1673           for (int i = 0; i < lock_ops.length(); i++) {
1674             AbstractLockNode* lock = lock_ops.at(i);
1675             if (lock->Opcode() == Op_Lock)
1676               locks++;
1677             else
1678               unlocks++;
1679             if (Verbose) {
1680               lock->dump(1);
1681             }
1682           }
1683           tty->print_cr("***Eliminated %d unlocks and %d locks", unlocks, locks);
1684         }
1685   #endif
1686 
1687         // for each of the identified locks, mark them
1688         // as eliminatable
1689         for (int i = 0; i < lock_ops.length(); i++) {
1690           AbstractLockNode* lock = lock_ops.at(i);
1691 
1692           // Mark it eliminated by coarsening and update any counters
1693           lock->set_coarsened();
1694         }
1695       } else if (ctrl->is_Region() &&
1696                  iter->_worklist.member(ctrl)) {
1697         // We weren't able to find any opportunities but the region this
1698         // lock is control dependent on hasn't been processed yet so put
1699         // this lock back on the worklist so we can check again once any
1700         // region simplification has occurred.
1701         iter->_worklist.push(this);
1702       }
1703     }
1704   }
1705 
1706   return result;
1707 }
1708 
1709 //=============================================================================
1710 bool LockNode::is_nested_lock_region() {
1711   BoxLockNode* box = box_node()->as_BoxLock();
1712   int stk_slot = box->stack_slot();
1713   if (stk_slot <= 0)
1714     return false; // External lock or it is not Box (Phi node).
1715 
1716   // Ignore complex cases: merged locks or multiple locks.
1717   Node* obj = obj_node();
1718   LockNode* unique_lock = NULL;
1719   if (!box->is_simple_lock_region(&unique_lock, obj) ||
1720       (unique_lock != this)) {
1721     return false;
1722   }
1723 
1724   // Look for external lock for the same object.
1725   SafePointNode* sfn = this->as_SafePoint();
1726   JVMState* youngest_jvms = sfn->jvms();
1727   int max_depth = youngest_jvms->depth();
1728   for (int depth = 1; depth <= max_depth; depth++) {
1729     JVMState* jvms = youngest_jvms->of_depth(depth);
1730     int num_mon  = jvms->nof_monitors();
1731     // Loop over monitors
1732     for (int idx = 0; idx < num_mon; idx++) {
1733       Node* obj_node = sfn->monitor_obj(jvms, idx);
1734       BoxLockNode* box_node = sfn->monitor_box(jvms, idx)->as_BoxLock();
1735       if ((box_node->stack_slot() < stk_slot) && obj_node->eqv_uncast(obj)) {
1736         return true;
1737       }
1738     }
1739   }
1740   return false;
1741 }
1742 
1743 //=============================================================================
1744 uint UnlockNode::size_of() const { return sizeof(*this); }
1745 
1746 //=============================================================================
1747 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1748 
1749   // perform any generic optimizations first (returns 'this' or NULL)
1750   Node *result = SafePointNode::Ideal(phase, can_reshape);
1751   if (result != NULL)  return result;
1752   // Don't bother trying to transform a dead node
1753   if (in(0) && in(0)->is_top())  return NULL;
1754 
1755   // Now see if we can optimize away this unlock.  We don't actually
1756   // remove the unlocking here, we simply set the _eliminate flag which
1757   // prevents macro expansion from expanding the unlock.  Since we don't
1758   // modify the graph, the value returned from this function is the
1759   // one computed above.
1760   // Escape state is defined after Parse phase.
1761   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1762     //
1763     // If we are unlocking an unescaped object, the lock/unlock is unnecessary.
1764     //
1765     ConnectionGraph *cgr = phase->C->congraph();
1766     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1767       assert(!is_eliminated() || is_coarsened(), "sanity");
1768       // The lock could be marked eliminated by lock coarsening
1769       // code during first IGVN before EA. Replace coarsened flag
1770       // to eliminate all associated locks/unlocks.
1771       this->set_non_esc_obj();
1772     }
1773   }
1774   return result;
1775 }