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/castnode.hpp"
  31 #include "opto/escape.hpp"
  32 #include "opto/locknode.hpp"
  33 #include "opto/machnode.hpp"
  34 #include "opto/matcher.hpp"
  35 #include "opto/parse.hpp"
  36 #include "opto/regalloc.hpp"
  37 #include "opto/regmask.hpp"
  38 #include "opto/rootnode.hpp"
  39 #include "opto/runtime.hpp"
  40 
  41 // Portions of code courtesy of Clifford Click
  42 
  43 // Optimization - Graph Style
  44 
  45 //=============================================================================
  46 uint StartNode::size_of() const { return sizeof(*this); }
  47 uint StartNode::cmp( const Node &n ) const
  48 { return _domain == ((StartNode&)n)._domain; }
  49 const Type *StartNode::bottom_type() const { return _domain; }
  50 const Type *StartNode::Value(PhaseTransform *phase) const { return _domain; }
  51 #ifndef PRODUCT
  52 void StartNode::dump_spec(outputStream *st) const { st->print(" #"); _domain->dump_on(st);}
  53 #endif
  54 
  55 //------------------------------Ideal------------------------------------------
  56 Node *StartNode::Ideal(PhaseGVN *phase, bool can_reshape){
  57   return remove_dead_region(phase, can_reshape) ? this : NULL;
  58 }
  59 
  60 //------------------------------calling_convention-----------------------------
  61 void StartNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
  62   Matcher::calling_convention( sig_bt, parm_regs, argcnt, false );
  63 }
  64 
  65 //------------------------------Registers--------------------------------------
  66 const RegMask &StartNode::in_RegMask(uint) const {
  67   return RegMask::Empty;
  68 }
  69 
  70 //------------------------------match------------------------------------------
  71 // Construct projections for incoming parameters, and their RegMask info
  72 Node *StartNode::match( const ProjNode *proj, const Matcher *match ) {
  73   switch (proj->_con) {
  74   case TypeFunc::Control:
  75   case TypeFunc::I_O:
  76   case TypeFunc::Memory:
  77     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
  78   case TypeFunc::FramePtr:
  79     return new (match->C) MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);
  80   case TypeFunc::ReturnAdr:
  81     return new (match->C) MachProjNode(this,proj->_con,match->_return_addr_mask,Op_RegP);
  82   case TypeFunc::Parms:
  83   default: {
  84       uint parm_num = proj->_con - TypeFunc::Parms;
  85       const Type *t = _domain->field_at(proj->_con);
  86       if (t->base() == Type::Half)  // 2nd half of Longs and Doubles
  87         return new (match->C) ConNode(Type::TOP);
  88       uint ideal_reg = t->ideal_reg();
  89       RegMask &rm = match->_calling_convention_mask[parm_num];
  90       return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);
  91     }
  92   }
  93   return NULL;
  94 }
  95 
  96 //------------------------------StartOSRNode----------------------------------
  97 // The method start node for an on stack replacement adapter
  98 
  99 //------------------------------osr_domain-----------------------------
 100 const TypeTuple *StartOSRNode::osr_domain() {
 101   const Type **fields = TypeTuple::fields(2);
 102   fields[TypeFunc::Parms+0] = TypeRawPtr::BOTTOM;  // address of osr buffer
 103 
 104   return TypeTuple::make(TypeFunc::Parms+1, fields);
 105 }
 106 
 107 //=============================================================================
 108 const char * const ParmNode::names[TypeFunc::Parms+1] = {
 109   "Control", "I_O", "Memory", "FramePtr", "ReturnAdr", "Parms"
 110 };
 111 
 112 #ifndef PRODUCT
 113 void ParmNode::dump_spec(outputStream *st) const {
 114   if( _con < TypeFunc::Parms ) {
 115     st->print(names[_con]);
 116   } else {
 117     st->print("Parm%d: ",_con-TypeFunc::Parms);
 118     // Verbose and WizardMode dump bottom_type for all nodes
 119     if( !Verbose && !WizardMode )   bottom_type()->dump_on(st);
 120   }
 121 }
 122 #endif
 123 
 124 uint ParmNode::ideal_reg() const {
 125   switch( _con ) {
 126   case TypeFunc::Control  : // fall through
 127   case TypeFunc::I_O      : // fall through
 128   case TypeFunc::Memory   : return 0;
 129   case TypeFunc::FramePtr : // fall through
 130   case TypeFunc::ReturnAdr: return Op_RegP;
 131   default                 : assert( _con > TypeFunc::Parms, "" );
 132     // fall through
 133   case TypeFunc::Parms    : {
 134     // Type of argument being passed
 135     const Type *t = in(0)->as_Start()->_domain->field_at(_con);
 136     return t->ideal_reg();
 137   }
 138   }
 139   ShouldNotReachHere();
 140   return 0;
 141 }
 142 
 143 //=============================================================================
 144 ReturnNode::ReturnNode(uint edges, Node *cntrl, Node *i_o, Node *memory, Node *frameptr, Node *retadr ) : Node(edges) {
 145   init_req(TypeFunc::Control,cntrl);
 146   init_req(TypeFunc::I_O,i_o);
 147   init_req(TypeFunc::Memory,memory);
 148   init_req(TypeFunc::FramePtr,frameptr);
 149   init_req(TypeFunc::ReturnAdr,retadr);
 150 }
 151 
 152 Node *ReturnNode::Ideal(PhaseGVN *phase, bool can_reshape){
 153   return remove_dead_region(phase, can_reshape) ? this : NULL;
 154 }
 155 
 156 const Type *ReturnNode::Value( PhaseTransform *phase ) const {
 157   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
 158     ? Type::TOP
 159     : Type::BOTTOM;
 160 }
 161 
 162 // Do we Match on this edge index or not?  No edges on return nodes
 163 uint ReturnNode::match_edge(uint idx) const {
 164   return 0;
 165 }
 166 
 167 
 168 #ifndef PRODUCT
 169 void ReturnNode::dump_req(outputStream *st) const {
 170   // Dump the required inputs, enclosed in '(' and ')'
 171   uint i;                       // Exit value of loop
 172   for (i = 0; i < req(); i++) {    // For all required inputs
 173     if (i == TypeFunc::Parms) st->print("returns");
 174     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 175     else st->print("_ ");
 176   }
 177 }
 178 #endif
 179 
 180 //=============================================================================
 181 RethrowNode::RethrowNode(
 182   Node* cntrl,
 183   Node* i_o,
 184   Node* memory,
 185   Node* frameptr,
 186   Node* ret_adr,
 187   Node* exception
 188 ) : Node(TypeFunc::Parms + 1) {
 189   init_req(TypeFunc::Control  , cntrl    );
 190   init_req(TypeFunc::I_O      , i_o      );
 191   init_req(TypeFunc::Memory   , memory   );
 192   init_req(TypeFunc::FramePtr , frameptr );
 193   init_req(TypeFunc::ReturnAdr, ret_adr);
 194   init_req(TypeFunc::Parms    , exception);
 195 }
 196 
 197 Node *RethrowNode::Ideal(PhaseGVN *phase, bool can_reshape){
 198   return remove_dead_region(phase, can_reshape) ? this : NULL;
 199 }
 200 
 201 const Type *RethrowNode::Value( PhaseTransform *phase ) const {
 202   return (phase->type(in(TypeFunc::Control)) == Type::TOP)
 203     ? Type::TOP
 204     : Type::BOTTOM;
 205 }
 206 
 207 uint RethrowNode::match_edge(uint idx) const {
 208   return 0;
 209 }
 210 
 211 #ifndef PRODUCT
 212 void RethrowNode::dump_req(outputStream *st) const {
 213   // Dump the required inputs, enclosed in '(' and ')'
 214   uint i;                       // Exit value of loop
 215   for (i = 0; i < req(); i++) {    // For all required inputs
 216     if (i == TypeFunc::Parms) st->print("exception");
 217     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 218     else st->print("_ ");
 219   }
 220 }
 221 #endif
 222 
 223 //=============================================================================
 224 // Do we Match on this edge index or not?  Match only target address & method
 225 uint TailCallNode::match_edge(uint idx) const {
 226   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 227 }
 228 
 229 //=============================================================================
 230 // Do we Match on this edge index or not?  Match only target address & oop
 231 uint TailJumpNode::match_edge(uint idx) const {
 232   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;
 233 }
 234 
 235 //=============================================================================
 236 JVMState::JVMState(ciMethod* method, JVMState* caller) :
 237   _method(method) {
 238   assert(method != NULL, "must be valid call site");
 239   _reexecute = Reexecute_Undefined;
 240   debug_only(_bci = -99);  // random garbage value
 241   debug_only(_map = (SafePointNode*)-1);
 242   _caller = caller;
 243   _depth  = 1 + (caller == NULL ? 0 : caller->depth());
 244   _locoff = TypeFunc::Parms;
 245   _stkoff = _locoff + _method->max_locals();
 246   _monoff = _stkoff + _method->max_stack();
 247   _scloff = _monoff;
 248   _endoff = _monoff;
 249   _sp = 0;
 250 }
 251 JVMState::JVMState(int stack_size) :
 252   _method(NULL) {
 253   _bci = InvocationEntryBci;
 254   _reexecute = Reexecute_Undefined;
 255   debug_only(_map = (SafePointNode*)-1);
 256   _caller = NULL;
 257   _depth  = 1;
 258   _locoff = TypeFunc::Parms;
 259   _stkoff = _locoff;
 260   _monoff = _stkoff + stack_size;
 261   _scloff = _monoff;
 262   _endoff = _monoff;
 263   _sp = 0;
 264 }
 265 
 266 //--------------------------------of_depth-------------------------------------
 267 JVMState* JVMState::of_depth(int d) const {
 268   const JVMState* jvmp = this;
 269   assert(0 < d && (uint)d <= depth(), "oob");
 270   for (int skip = depth() - d; skip > 0; skip--) {
 271     jvmp = jvmp->caller();
 272   }
 273   assert(jvmp->depth() == (uint)d, "found the right one");
 274   return (JVMState*)jvmp;
 275 }
 276 
 277 //-----------------------------same_calls_as-----------------------------------
 278 bool JVMState::same_calls_as(const JVMState* that) const {
 279   if (this == that)                    return true;
 280   if (this->depth() != that->depth())  return false;
 281   const JVMState* p = this;
 282   const JVMState* q = that;
 283   for (;;) {
 284     if (p->_method != q->_method)    return false;
 285     if (p->_method == NULL)          return true;   // bci is irrelevant
 286     if (p->_bci    != q->_bci)       return false;
 287     if (p->_reexecute != q->_reexecute)  return false;
 288     p = p->caller();
 289     q = q->caller();
 290     if (p == q)                      return true;
 291     assert(p != NULL && q != NULL, "depth check ensures we don't run off end");
 292   }
 293 }
 294 
 295 //------------------------------debug_start------------------------------------
 296 uint JVMState::debug_start()  const {
 297   debug_only(JVMState* jvmroot = of_depth(1));
 298   assert(jvmroot->locoff() <= this->locoff(), "youngest JVMState must be last");
 299   return of_depth(1)->locoff();
 300 }
 301 
 302 //-------------------------------debug_end-------------------------------------
 303 uint JVMState::debug_end() const {
 304   debug_only(JVMState* jvmroot = of_depth(1));
 305   assert(jvmroot->endoff() <= this->endoff(), "youngest JVMState must be last");
 306   return endoff();
 307 }
 308 
 309 //------------------------------debug_depth------------------------------------
 310 uint JVMState::debug_depth() const {
 311   uint total = 0;
 312   for (const JVMState* jvmp = this; jvmp != NULL; jvmp = jvmp->caller()) {
 313     total += jvmp->debug_size();
 314   }
 315   return total;
 316 }
 317 
 318 #ifndef PRODUCT
 319 
 320 //------------------------------format_helper----------------------------------
 321 // Given an allocation (a Chaitin object) and a Node decide if the Node carries
 322 // any defined value or not.  If it does, print out the register or constant.
 323 static void format_helper( PhaseRegAlloc *regalloc, outputStream* st, Node *n, const char *msg, uint i, GrowableArray<SafePointScalarObjectNode*> *scobjs ) {
 324   if (n == NULL) { st->print(" NULL"); return; }
 325   if (n->is_SafePointScalarObject()) {
 326     // Scalar replacement.
 327     SafePointScalarObjectNode* spobj = n->as_SafePointScalarObject();
 328     scobjs->append_if_missing(spobj);
 329     int sco_n = scobjs->find(spobj);
 330     assert(sco_n >= 0, "");
 331     st->print(" %s%d]=#ScObj" INT32_FORMAT, msg, i, sco_n);
 332     return;
 333   }
 334   if (regalloc->node_regs_max_index() > 0 &&
 335       OptoReg::is_valid(regalloc->get_reg_first(n))) { // Check for undefined
 336     char buf[50];
 337     regalloc->dump_register(n,buf);
 338     st->print(" %s%d]=%s",msg,i,buf);
 339   } else {                      // No register, but might be constant
 340     const Type *t = n->bottom_type();
 341     switch (t->base()) {
 342     case Type::Int:
 343       st->print(" %s%d]=#"INT32_FORMAT,msg,i,t->is_int()->get_con());
 344       break;
 345     case Type::AnyPtr:
 346       assert( t == TypePtr::NULL_PTR || n->in_dump(), "" );
 347       st->print(" %s%d]=#NULL",msg,i);
 348       break;
 349     case Type::AryPtr:
 350     case Type::InstPtr:
 351       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->isa_oopptr()->const_oop());
 352       break;
 353     case Type::KlassPtr:
 354       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_klassptr()->klass());
 355       break;
 356     case Type::MetadataPtr:
 357       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_metadataptr()->metadata());
 358       break;
 359     case Type::NarrowOop:
 360       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_oopptr()->const_oop());
 361       break;
 362     case Type::RawPtr:
 363       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,t->is_rawptr());
 364       break;
 365     case Type::DoubleCon:
 366       st->print(" %s%d]=#%fD",msg,i,t->is_double_constant()->_d);
 367       break;
 368     case Type::FloatCon:
 369       st->print(" %s%d]=#%fF",msg,i,t->is_float_constant()->_f);
 370       break;
 371     case Type::Long:
 372       st->print(" %s%d]=#"INT64_FORMAT,msg,i,t->is_long()->get_con());
 373       break;
 374     case Type::Half:
 375     case Type::Top:
 376       st->print(" %s%d]=_",msg,i);
 377       break;
 378     default: ShouldNotReachHere();
 379     }
 380   }
 381 }
 382 
 383 //------------------------------format-----------------------------------------
 384 void JVMState::format(PhaseRegAlloc *regalloc, const Node *n, outputStream* st) const {
 385   st->print("        #");
 386   if (_method) {
 387     _method->print_short_name(st);
 388     st->print(" @ bci:%d ",_bci);
 389   } else {
 390     st->print_cr(" runtime stub ");
 391     return;
 392   }
 393   if (n->is_MachSafePoint()) {
 394     GrowableArray<SafePointScalarObjectNode*> scobjs;
 395     MachSafePointNode *mcall = n->as_MachSafePoint();
 396     uint i;
 397     // Print locals
 398     for (i = 0; i < (uint)loc_size(); i++)
 399       format_helper(regalloc, st, mcall->local(this, i), "L[", i, &scobjs);
 400     // Print stack
 401     for (i = 0; i < (uint)stk_size(); i++) {
 402       if ((uint)(_stkoff + i) >= mcall->len())
 403         st->print(" oob ");
 404       else
 405        format_helper(regalloc, st, mcall->stack(this, i), "STK[", i, &scobjs);
 406     }
 407     for (i = 0; (int)i < nof_monitors(); i++) {
 408       Node *box = mcall->monitor_box(this, i);
 409       Node *obj = mcall->monitor_obj(this, i);
 410       if (regalloc->node_regs_max_index() > 0 &&
 411           OptoReg::is_valid(regalloc->get_reg_first(box))) {
 412         box = BoxLockNode::box_node(box);
 413         format_helper(regalloc, st, box, "MON-BOX[", i, &scobjs);
 414       } else {
 415         OptoReg::Name box_reg = BoxLockNode::reg(box);
 416         st->print(" MON-BOX%d=%s+%d",
 417                    i,
 418                    OptoReg::regname(OptoReg::c_frame_pointer),
 419                    regalloc->reg2offset(box_reg));
 420       }
 421       const char* obj_msg = "MON-OBJ[";
 422       if (EliminateLocks) {
 423         if (BoxLockNode::box_node(box)->is_eliminated())
 424           obj_msg = "MON-OBJ(LOCK ELIMINATED)[";
 425       }
 426       format_helper(regalloc, st, obj, obj_msg, i, &scobjs);
 427     }
 428 
 429     for (i = 0; i < (uint)scobjs.length(); i++) {
 430       // Scalar replaced objects.
 431       st->print_cr("");
 432       st->print("        # ScObj" INT32_FORMAT " ", i);
 433       SafePointScalarObjectNode* spobj = scobjs.at(i);
 434       ciKlass* cik = spobj->bottom_type()->is_oopptr()->klass();
 435       assert(cik->is_instance_klass() ||
 436              cik->is_array_klass(), "Not supported allocation.");
 437       ciInstanceKlass *iklass = NULL;
 438       if (cik->is_instance_klass()) {
 439         cik->print_name_on(st);
 440         iklass = cik->as_instance_klass();
 441       } else if (cik->is_type_array_klass()) {
 442         cik->as_array_klass()->base_element_type()->print_name_on(st);
 443         st->print("[%d]", spobj->n_fields());
 444       } else if (cik->is_obj_array_klass()) {
 445         ciKlass* cie = cik->as_obj_array_klass()->base_element_klass();
 446         if (cie->is_instance_klass()) {
 447           cie->print_name_on(st);
 448         } else if (cie->is_type_array_klass()) {
 449           cie->as_array_klass()->base_element_type()->print_name_on(st);
 450         } else {
 451           ShouldNotReachHere();
 452         }
 453         st->print("[%d]", spobj->n_fields());
 454         int ndim = cik->as_array_klass()->dimension() - 1;
 455         while (ndim-- > 0) {
 456           st->print("[]");
 457         }
 458       }
 459       st->print("={");
 460       uint nf = spobj->n_fields();
 461       if (nf > 0) {
 462         uint first_ind = spobj->first_index(mcall->jvms());
 463         Node* fld_node = mcall->in(first_ind);
 464         ciField* cifield;
 465         if (iklass != NULL) {
 466           st->print(" [");
 467           cifield = iklass->nonstatic_field_at(0);
 468           cifield->print_name_on(st);
 469           format_helper(regalloc, st, fld_node, ":", 0, &scobjs);
 470         } else {
 471           format_helper(regalloc, st, fld_node, "[", 0, &scobjs);
 472         }
 473         for (uint j = 1; j < nf; j++) {
 474           fld_node = mcall->in(first_ind+j);
 475           if (iklass != NULL) {
 476             st->print(", [");
 477             cifield = iklass->nonstatic_field_at(j);
 478             cifield->print_name_on(st);
 479             format_helper(regalloc, st, fld_node, ":", j, &scobjs);
 480           } else {
 481             format_helper(regalloc, st, fld_node, ", [", j, &scobjs);
 482           }
 483         }
 484       }
 485       st->print(" }");
 486     }
 487   }
 488   st->print_cr("");
 489   if (caller() != NULL) caller()->format(regalloc, n, st);
 490 }
 491 
 492 
 493 void JVMState::dump_spec(outputStream *st) const {
 494   if (_method != NULL) {
 495     bool printed = false;
 496     if (!Verbose) {
 497       // The JVMS dumps make really, really long lines.
 498       // Take out the most boring parts, which are the package prefixes.
 499       char buf[500];
 500       stringStream namest(buf, sizeof(buf));
 501       _method->print_short_name(&namest);
 502       if (namest.count() < sizeof(buf)) {
 503         const char* name = namest.base();
 504         if (name[0] == ' ')  ++name;
 505         const char* endcn = strchr(name, ':');  // end of class name
 506         if (endcn == NULL)  endcn = strchr(name, '(');
 507         if (endcn == NULL)  endcn = name + strlen(name);
 508         while (endcn > name && endcn[-1] != '.' && endcn[-1] != '/')
 509           --endcn;
 510         st->print(" %s", endcn);
 511         printed = true;
 512       }
 513     }
 514     if (!printed)
 515       _method->print_short_name(st);
 516     st->print(" @ bci:%d",_bci);
 517     if(_reexecute == Reexecute_True)
 518       st->print(" reexecute");
 519   } else {
 520     st->print(" runtime stub");
 521   }
 522   if (caller() != NULL)  caller()->dump_spec(st);
 523 }
 524 
 525 
 526 void JVMState::dump_on(outputStream* st) const {
 527   bool print_map = _map && !((uintptr_t)_map & 1) &&
 528                   ((caller() == NULL) || (caller()->map() != _map));
 529   if (print_map) {
 530     if (_map->len() > _map->req()) {  // _map->has_exceptions()
 531       Node* ex = _map->in(_map->req());  // _map->next_exception()
 532       // skip the first one; it's already being printed
 533       while (ex != NULL && ex->len() > ex->req()) {
 534         ex = ex->in(ex->req());  // ex->next_exception()
 535         ex->dump(1);
 536       }
 537     }
 538     _map->dump(Verbose ? 2 : 1);
 539   }
 540   if (caller() != NULL) {
 541     caller()->dump_on(st);
 542   }
 543   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=",
 544              depth(), locoff(), stkoff(), argoff(), monoff(), scloff(), endoff(), monitor_depth(), sp(), bci(), should_reexecute()?"true":"false");
 545   if (_method == NULL) {
 546     st->print_cr("(none)");
 547   } else {
 548     _method->print_name(st);
 549     st->cr();
 550     if (bci() >= 0 && bci() < _method->code_size()) {
 551       st->print("    bc: ");
 552       _method->print_codes_on(bci(), bci()+1, st);
 553     }
 554   }
 555 }
 556 
 557 // Extra way to dump a jvms from the debugger,
 558 // to avoid a bug with C++ member function calls.
 559 void dump_jvms(JVMState* jvms) {
 560   jvms->dump();
 561 }
 562 #endif
 563 
 564 //--------------------------clone_shallow--------------------------------------
 565 JVMState* JVMState::clone_shallow(Compile* C) const {
 566   JVMState* n = has_method() ? new (C) JVMState(_method, _caller) : new (C) JVMState(0);
 567   n->set_bci(_bci);
 568   n->_reexecute = _reexecute;
 569   n->set_locoff(_locoff);
 570   n->set_stkoff(_stkoff);
 571   n->set_monoff(_monoff);
 572   n->set_scloff(_scloff);
 573   n->set_endoff(_endoff);
 574   n->set_sp(_sp);
 575   n->set_map(_map);
 576   return n;
 577 }
 578 
 579 //---------------------------clone_deep----------------------------------------
 580 JVMState* JVMState::clone_deep(Compile* C) const {
 581   JVMState* n = clone_shallow(C);
 582   for (JVMState* p = n; p->_caller != NULL; p = p->_caller) {
 583     p->_caller = p->_caller->clone_shallow(C);
 584   }
 585   assert(n->depth() == depth(), "sanity");
 586   assert(n->debug_depth() == debug_depth(), "sanity");
 587   return n;
 588 }
 589 
 590 /**
 591  * Reset map for all callers
 592  */
 593 void JVMState::set_map_deep(SafePointNode* map) {
 594   for (JVMState* p = this; p->_caller != NULL; p = p->_caller) {
 595     p->set_map(map);
 596   }
 597 }
 598 
 599 // Adapt offsets in in-array after adding or removing an edge.
 600 // Prerequisite is that the JVMState is used by only one node.
 601 void JVMState::adapt_position(int delta) {
 602   for (JVMState* jvms = this; jvms != NULL; jvms = jvms->caller()) {
 603     jvms->set_locoff(jvms->locoff() + delta);
 604     jvms->set_stkoff(jvms->stkoff() + delta);
 605     jvms->set_monoff(jvms->monoff() + delta);
 606     jvms->set_scloff(jvms->scloff() + delta);
 607     jvms->set_endoff(jvms->endoff() + delta);
 608   }
 609 }
 610 
 611 //=============================================================================
 612 uint CallNode::cmp( const Node &n ) const
 613 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }
 614 #ifndef PRODUCT
 615 void CallNode::dump_req(outputStream *st) const {
 616   // Dump the required inputs, enclosed in '(' and ')'
 617   uint i;                       // Exit value of loop
 618   for (i = 0; i < req(); i++) {    // For all required inputs
 619     if (i == TypeFunc::Parms) st->print("(");
 620     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 621     else st->print("_ ");
 622   }
 623   st->print(")");
 624 }
 625 
 626 void CallNode::dump_spec(outputStream *st) const {
 627   st->print(" ");
 628   tf()->dump_on(st);
 629   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);
 630   if (jvms() != NULL)  jvms()->dump_spec(st);
 631 }
 632 #endif
 633 
 634 const Type *CallNode::bottom_type() const { return tf()->range(); }
 635 const Type *CallNode::Value(PhaseTransform *phase) const {
 636   if (phase->type(in(0)) == Type::TOP)  return Type::TOP;
 637   return tf()->range();
 638 }
 639 
 640 //------------------------------calling_convention-----------------------------
 641 void CallNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 642   // Use the standard compiler calling convention
 643   Matcher::calling_convention( sig_bt, parm_regs, argcnt, true );
 644 }
 645 
 646 
 647 //------------------------------match------------------------------------------
 648 // Construct projections for control, I/O, memory-fields, ..., and
 649 // return result(s) along with their RegMask info
 650 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {
 651   switch (proj->_con) {
 652   case TypeFunc::Control:
 653   case TypeFunc::I_O:
 654   case TypeFunc::Memory:
 655     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
 656 
 657   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns
 658     assert(tf()->_range->field_at(TypeFunc::Parms+1) == Type::HALF, "");
 659     // 2nd half of doubles and longs
 660     return new (match->C) MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);
 661 
 662   case TypeFunc::Parms: {       // Normal returns
 663     uint ideal_reg = tf()->range()->field_at(TypeFunc::Parms)->ideal_reg();
 664     OptoRegPair regs = is_CallRuntime()
 665       ? match->c_return_value(ideal_reg,true)  // Calls into C runtime
 666       : match->  return_value(ideal_reg,true); // Calls into compiled Java code
 667     RegMask rm = RegMask(regs.first());
 668     if( OptoReg::is_valid(regs.second()) )
 669       rm.Insert( regs.second() );
 670     return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);
 671   }
 672 
 673   case TypeFunc::ReturnAdr:
 674   case TypeFunc::FramePtr:
 675   default:
 676     ShouldNotReachHere();
 677   }
 678   return NULL;
 679 }
 680 
 681 // Do we Match on this edge index or not?  Match no edges
 682 uint CallNode::match_edge(uint idx) const {
 683   return 0;
 684 }
 685 
 686 //
 687 // Determine whether the call could modify the field of the specified
 688 // instance at the specified offset.
 689 //
 690 bool CallNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 691   assert((t_oop != NULL), "sanity");
 692   if (t_oop->is_known_instance()) {
 693     // The instance_id is set only for scalar-replaceable allocations which
 694     // are not passed as arguments according to Escape Analysis.
 695     return false;
 696   }
 697   if (t_oop->is_ptr_to_boxed_value()) {
 698     ciKlass* boxing_klass = t_oop->klass();
 699     if (is_CallStaticJava() && as_CallStaticJava()->is_boxing_method()) {
 700       // Skip unrelated boxing methods.
 701       Node* proj = proj_out(TypeFunc::Parms);
 702       if ((proj == NULL) || (phase->type(proj)->is_instptr()->klass() != boxing_klass)) {
 703         return false;
 704       }
 705     }
 706     if (is_CallJava() && as_CallJava()->method() != NULL) {
 707       ciMethod* meth = as_CallJava()->method();
 708       if (meth->is_accessor()) {
 709         return false;
 710       }
 711       // May modify (by reflection) if an boxing object is passed
 712       // as argument or returned.
 713       if (returns_pointer() && (proj_out(TypeFunc::Parms) != NULL)) {
 714         Node* proj = proj_out(TypeFunc::Parms);
 715         const TypeInstPtr* inst_t = phase->type(proj)->isa_instptr();
 716         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 717                                  (inst_t->klass() == boxing_klass))) {
 718           return true;
 719         }
 720       }
 721       const TypeTuple* d = tf()->domain();
 722       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 723         const TypeInstPtr* inst_t = d->field_at(i)->isa_instptr();
 724         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 725                                  (inst_t->klass() == boxing_klass))) {
 726           return true;
 727         }
 728       }
 729       return false;
 730     }
 731   }
 732   return true;
 733 }
 734 
 735 // Does this call have a direct reference to n other than debug information?
 736 bool CallNode::has_non_debug_use(Node *n) {
 737   const TypeTuple * d = tf()->domain();
 738   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 739     Node *arg = in(i);
 740     if (arg == n) {
 741       return true;
 742     }
 743   }
 744   return false;
 745 }
 746 
 747 // Returns the unique CheckCastPP of a call
 748 // or 'this' if there are several CheckCastPP
 749 // or returns NULL if there is no one.
 750 Node *CallNode::result_cast() {
 751   Node *cast = NULL;
 752 
 753   Node *p = proj_out(TypeFunc::Parms);
 754   if (p == NULL)
 755     return NULL;
 756 
 757   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {
 758     Node *use = p->fast_out(i);
 759     if (use->is_CheckCastPP()) {
 760       if (cast != NULL) {
 761         return this;  // more than 1 CheckCastPP
 762       }
 763       cast = use;
 764     }
 765   }
 766   return cast;
 767 }
 768 
 769 
 770 void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj) {
 771   projs->fallthrough_proj      = NULL;
 772   projs->fallthrough_catchproj = NULL;
 773   projs->fallthrough_ioproj    = NULL;
 774   projs->catchall_ioproj       = NULL;
 775   projs->catchall_catchproj    = NULL;
 776   projs->fallthrough_memproj   = NULL;
 777   projs->catchall_memproj      = NULL;
 778   projs->resproj               = NULL;
 779   projs->exobj                 = NULL;
 780 
 781   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 782     ProjNode *pn = fast_out(i)->as_Proj();
 783     if (pn->outcnt() == 0) continue;
 784     switch (pn->_con) {
 785     case TypeFunc::Control:
 786       {
 787         // For Control (fallthrough) and I_O (catch_all_index) we have CatchProj -> Catch -> Proj
 788         projs->fallthrough_proj = pn;
 789         DUIterator_Fast jmax, j = pn->fast_outs(jmax);
 790         const Node *cn = pn->fast_out(j);
 791         if (cn->is_Catch()) {
 792           ProjNode *cpn = NULL;
 793           for (DUIterator_Fast kmax, k = cn->fast_outs(kmax); k < kmax; k++) {
 794             cpn = cn->fast_out(k)->as_Proj();
 795             assert(cpn->is_CatchProj(), "must be a CatchProjNode");
 796             if (cpn->_con == CatchProjNode::fall_through_index)
 797               projs->fallthrough_catchproj = cpn;
 798             else {
 799               assert(cpn->_con == CatchProjNode::catch_all_index, "must be correct index.");
 800               projs->catchall_catchproj = cpn;
 801             }
 802           }
 803         }
 804         break;
 805       }
 806     case TypeFunc::I_O:
 807       if (pn->_is_io_use)
 808         projs->catchall_ioproj = pn;
 809       else
 810         projs->fallthrough_ioproj = pn;
 811       for (DUIterator j = pn->outs(); pn->has_out(j); j++) {
 812         Node* e = pn->out(j);
 813         if (e->Opcode() == Op_CreateEx && e->in(0)->is_CatchProj() && e->outcnt() > 0) {
 814           assert(projs->exobj == NULL, "only one");
 815           projs->exobj = e;
 816         }
 817       }
 818       break;
 819     case TypeFunc::Memory:
 820       if (pn->_is_io_use)
 821         projs->catchall_memproj = pn;
 822       else
 823         projs->fallthrough_memproj = pn;
 824       break;
 825     case TypeFunc::Parms:
 826       projs->resproj = pn;
 827       break;
 828     default:
 829       assert(false, "unexpected projection from allocation node.");
 830     }
 831   }
 832 
 833   // The resproj may not exist because the result couuld be ignored
 834   // and the exception object may not exist if an exception handler
 835   // swallows the exception but all the other must exist and be found.
 836   assert(projs->fallthrough_proj      != NULL, "must be found");
 837   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_catchproj != NULL, "must be found");
 838   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_memproj   != NULL, "must be found");
 839   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_ioproj    != NULL, "must be found");
 840   assert(Compile::current()->inlining_incrementally() || projs->catchall_catchproj    != NULL, "must be found");
 841   if (separate_io_proj) {
 842     assert(Compile::current()->inlining_incrementally() || projs->catchall_memproj    != NULL, "must be found");
 843     assert(Compile::current()->inlining_incrementally() || projs->catchall_ioproj     != NULL, "must be found");
 844   }
 845 }
 846 
 847 Node *CallNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 848   CallGenerator* cg = generator();
 849   if (can_reshape && cg != NULL && cg->is_mh_late_inline() && !cg->already_attempted()) {
 850     // Check whether this MH handle call becomes a candidate for inlining
 851     ciMethod* callee = cg->method();
 852     vmIntrinsics::ID iid = callee->intrinsic_id();
 853     if (iid == vmIntrinsics::_invokeBasic) {
 854       if (in(TypeFunc::Parms)->Opcode() == Op_ConP) {
 855         phase->C->prepend_late_inline(cg);
 856         set_generator(NULL);
 857       }
 858     } else {
 859       assert(callee->has_member_arg(), "wrong type of call?");
 860       if (in(TypeFunc::Parms + callee->arg_size() - 1)->Opcode() == Op_ConP) {
 861         phase->C->prepend_late_inline(cg);
 862         set_generator(NULL);
 863       }
 864     }
 865   }
 866   return SafePointNode::Ideal(phase, can_reshape);
 867 }
 868 
 869 
 870 //=============================================================================
 871 uint CallJavaNode::size_of() const { return sizeof(*this); }
 872 uint CallJavaNode::cmp( const Node &n ) const {
 873   CallJavaNode &call = (CallJavaNode&)n;
 874   return CallNode::cmp(call) && _method == call._method;
 875 }
 876 #ifndef PRODUCT
 877 void CallJavaNode::dump_spec(outputStream *st) const {
 878   if( _method ) _method->print_short_name(st);
 879   CallNode::dump_spec(st);
 880 }
 881 #endif
 882 
 883 //=============================================================================
 884 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }
 885 uint CallStaticJavaNode::cmp( const Node &n ) const {
 886   CallStaticJavaNode &call = (CallStaticJavaNode&)n;
 887   return CallJavaNode::cmp(call);
 888 }
 889 
 890 //----------------------------uncommon_trap_request----------------------------
 891 // If this is an uncommon trap, return the request code, else zero.
 892 int CallStaticJavaNode::uncommon_trap_request() const {
 893   if (_name != NULL && !strcmp(_name, "uncommon_trap")) {
 894     return extract_uncommon_trap_request(this);
 895   }
 896   return 0;
 897 }
 898 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {
 899 #ifndef PRODUCT
 900   if (!(call->req() > TypeFunc::Parms &&
 901         call->in(TypeFunc::Parms) != NULL &&
 902         call->in(TypeFunc::Parms)->is_Con())) {
 903     assert(in_dump() != 0, "OK if dumping");
 904     tty->print("[bad uncommon trap]");
 905     return 0;
 906   }
 907 #endif
 908   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();
 909 }
 910 
 911 #ifndef PRODUCT
 912 void CallStaticJavaNode::dump_spec(outputStream *st) const {
 913   st->print("# Static ");
 914   if (_name != NULL) {
 915     st->print("%s", _name);
 916     int trap_req = uncommon_trap_request();
 917     if (trap_req != 0) {
 918       char buf[100];
 919       st->print("(%s)",
 920                  Deoptimization::format_trap_request(buf, sizeof(buf),
 921                                                      trap_req));
 922     }
 923     st->print(" ");
 924   }
 925   CallJavaNode::dump_spec(st);
 926 }
 927 #endif
 928 
 929 //=============================================================================
 930 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }
 931 uint CallDynamicJavaNode::cmp( const Node &n ) const {
 932   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;
 933   return CallJavaNode::cmp(call);
 934 }
 935 #ifndef PRODUCT
 936 void CallDynamicJavaNode::dump_spec(outputStream *st) const {
 937   st->print("# Dynamic ");
 938   CallJavaNode::dump_spec(st);
 939 }
 940 #endif
 941 
 942 //=============================================================================
 943 uint CallRuntimeNode::size_of() const { return sizeof(*this); }
 944 uint CallRuntimeNode::cmp( const Node &n ) const {
 945   CallRuntimeNode &call = (CallRuntimeNode&)n;
 946   return CallNode::cmp(call) && !strcmp(_name,call._name);
 947 }
 948 #ifndef PRODUCT
 949 void CallRuntimeNode::dump_spec(outputStream *st) const {
 950   st->print("# ");
 951   st->print(_name);
 952   CallNode::dump_spec(st);
 953 }
 954 #endif
 955 
 956 //------------------------------calling_convention-----------------------------
 957 void CallRuntimeNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 958   Matcher::c_calling_convention( sig_bt, parm_regs, argcnt );
 959 }
 960 
 961 //=============================================================================
 962 //------------------------------calling_convention-----------------------------
 963 
 964 
 965 //=============================================================================
 966 #ifndef PRODUCT
 967 void CallLeafNode::dump_spec(outputStream *st) const {
 968   st->print("# ");
 969   st->print(_name);
 970   CallNode::dump_spec(st);
 971 }
 972 #endif
 973 
 974 //=============================================================================
 975 
 976 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {
 977   assert(verify_jvms(jvms), "jvms must match");
 978   int loc = jvms->locoff() + idx;
 979   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {
 980     // If current local idx is top then local idx - 1 could
 981     // be a long/double that needs to be killed since top could
 982     // represent the 2nd half ofthe long/double.
 983     uint ideal = in(loc -1)->ideal_reg();
 984     if (ideal == Op_RegD || ideal == Op_RegL) {
 985       // set other (low index) half to top
 986       set_req(loc - 1, in(loc));
 987     }
 988   }
 989   set_req(loc, c);
 990 }
 991 
 992 uint SafePointNode::size_of() const { return sizeof(*this); }
 993 uint SafePointNode::cmp( const Node &n ) const {
 994   return (&n == this);          // Always fail except on self
 995 }
 996 
 997 //-------------------------set_next_exception----------------------------------
 998 void SafePointNode::set_next_exception(SafePointNode* n) {
 999   assert(n == NULL || n->Opcode() == Op_SafePoint, "correct value for next_exception");
1000   if (len() == req()) {
1001     if (n != NULL)  add_prec(n);
1002   } else {
1003     set_prec(req(), n);
1004   }
1005 }
1006 
1007 
1008 //----------------------------next_exception-----------------------------------
1009 SafePointNode* SafePointNode::next_exception() const {
1010   if (len() == req()) {
1011     return NULL;
1012   } else {
1013     Node* n = in(req());
1014     assert(n == NULL || n->Opcode() == Op_SafePoint, "no other uses of prec edges");
1015     return (SafePointNode*) n;
1016   }
1017 }
1018 
1019 
1020 //------------------------------Ideal------------------------------------------
1021 // Skip over any collapsed Regions
1022 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1023   return remove_dead_region(phase, can_reshape) ? this : NULL;
1024 }
1025 
1026 //------------------------------Identity---------------------------------------
1027 // Remove obviously duplicate safepoints
1028 Node *SafePointNode::Identity( PhaseTransform *phase ) {
1029 
1030   // If you have back to back safepoints, remove one
1031   if( in(TypeFunc::Control)->is_SafePoint() )
1032     return in(TypeFunc::Control);
1033 
1034   if( in(0)->is_Proj() ) {
1035     Node *n0 = in(0)->in(0);
1036     // Check if he is a call projection (except Leaf Call)
1037     if( n0->is_Catch() ) {
1038       n0 = n0->in(0)->in(0);
1039       assert( n0->is_Call(), "expect a call here" );
1040     }
1041     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {
1042       // Useless Safepoint, so remove it
1043       return in(TypeFunc::Control);
1044     }
1045   }
1046 
1047   return this;
1048 }
1049 
1050 //------------------------------Value------------------------------------------
1051 const Type *SafePointNode::Value( PhaseTransform *phase ) const {
1052   if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
1053   if( phase->eqv( in(0), this ) ) return Type::TOP; // Dead infinite loop
1054   return Type::CONTROL;
1055 }
1056 
1057 #ifndef PRODUCT
1058 void SafePointNode::dump_spec(outputStream *st) const {
1059   st->print(" SafePoint ");
1060 }
1061 #endif
1062 
1063 const RegMask &SafePointNode::in_RegMask(uint idx) const {
1064   if( idx < TypeFunc::Parms ) return RegMask::Empty;
1065   // Values outside the domain represent debug info
1066   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1067 }
1068 const RegMask &SafePointNode::out_RegMask() const {
1069   return RegMask::Empty;
1070 }
1071 
1072 
1073 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {
1074   assert((int)grow_by > 0, "sanity");
1075   int monoff = jvms->monoff();
1076   int scloff = jvms->scloff();
1077   int endoff = jvms->endoff();
1078   assert(endoff == (int)req(), "no other states or debug info after me");
1079   Node* top = Compile::current()->top();
1080   for (uint i = 0; i < grow_by; i++) {
1081     ins_req(monoff, top);
1082   }
1083   jvms->set_monoff(monoff + grow_by);
1084   jvms->set_scloff(scloff + grow_by);
1085   jvms->set_endoff(endoff + grow_by);
1086 }
1087 
1088 void SafePointNode::push_monitor(const FastLockNode *lock) {
1089   // Add a LockNode, which points to both the original BoxLockNode (the
1090   // stack space for the monitor) and the Object being locked.
1091   const int MonitorEdges = 2;
1092   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1093   assert(req() == jvms()->endoff(), "correct sizing");
1094   int nextmon = jvms()->scloff();
1095   if (GenerateSynchronizationCode) {
1096     ins_req(nextmon,   lock->box_node());
1097     ins_req(nextmon+1, lock->obj_node());
1098   } else {
1099     Node* top = Compile::current()->top();
1100     ins_req(nextmon, top);
1101     ins_req(nextmon, top);
1102   }
1103   jvms()->set_scloff(nextmon + MonitorEdges);
1104   jvms()->set_endoff(req());
1105 }
1106 
1107 void SafePointNode::pop_monitor() {
1108   // Delete last monitor from debug info
1109   debug_only(int num_before_pop = jvms()->nof_monitors());
1110   const int MonitorEdges = 2;
1111   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1112   int scloff = jvms()->scloff();
1113   int endoff = jvms()->endoff();
1114   int new_scloff = scloff - MonitorEdges;
1115   int new_endoff = endoff - MonitorEdges;
1116   jvms()->set_scloff(new_scloff);
1117   jvms()->set_endoff(new_endoff);
1118   while (scloff > new_scloff)  del_req_ordered(--scloff);
1119   assert(jvms()->nof_monitors() == num_before_pop-1, "");
1120 }
1121 
1122 Node *SafePointNode::peek_monitor_box() const {
1123   int mon = jvms()->nof_monitors() - 1;
1124   assert(mon >= 0, "most have a monitor");
1125   return monitor_box(jvms(), mon);
1126 }
1127 
1128 Node *SafePointNode::peek_monitor_obj() const {
1129   int mon = jvms()->nof_monitors() - 1;
1130   assert(mon >= 0, "most have a monitor");
1131   return monitor_obj(jvms(), mon);
1132 }
1133 
1134 // Do we Match on this edge index or not?  Match no edges
1135 uint SafePointNode::match_edge(uint idx) const {
1136   if( !needs_polling_address_input() )
1137     return 0;
1138 
1139   return (TypeFunc::Parms == idx);
1140 }
1141 
1142 //==============  SafePointScalarObjectNode  ==============
1143 
1144 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp,
1145 #ifdef ASSERT
1146                                                      AllocateNode* alloc,
1147 #endif
1148                                                      uint first_index,
1149                                                      uint n_fields) :
1150   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
1151 #ifdef ASSERT
1152   _alloc(alloc),
1153 #endif
1154   _first_index(first_index),
1155   _n_fields(n_fields)
1156 {
1157   init_class_id(Class_SafePointScalarObject);
1158 }
1159 
1160 // Do not allow value-numbering for SafePointScalarObject node.
1161 uint SafePointScalarObjectNode::hash() const { return NO_HASH; }
1162 uint SafePointScalarObjectNode::cmp( const Node &n ) const {
1163   return (&n == this); // Always fail except on self
1164 }
1165 
1166 uint SafePointScalarObjectNode::ideal_reg() const {
1167   return 0; // No matching to machine instruction
1168 }
1169 
1170 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {
1171   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1172 }
1173 
1174 const RegMask &SafePointScalarObjectNode::out_RegMask() const {
1175   return RegMask::Empty;
1176 }
1177 
1178 uint SafePointScalarObjectNode::match_edge(uint idx) const {
1179   return 0;
1180 }
1181 
1182 SafePointScalarObjectNode*
1183 SafePointScalarObjectNode::clone(Dict* sosn_map) const {
1184   void* cached = (*sosn_map)[(void*)this];
1185   if (cached != NULL) {
1186     return (SafePointScalarObjectNode*)cached;
1187   }
1188   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();
1189   sosn_map->Insert((void*)this, (void*)res);
1190   return res;
1191 }
1192 
1193 
1194 #ifndef PRODUCT
1195 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {
1196   st->print(" # fields@[%d..%d]", first_index(),
1197              first_index() + n_fields() - 1);
1198 }
1199 
1200 #endif
1201 
1202 //=============================================================================
1203 uint AllocateNode::size_of() const { return sizeof(*this); }
1204 
1205 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,
1206                            Node *ctrl, Node *mem, Node *abio,
1207                            Node *size, Node *klass_node, Node *initial_test)
1208   : CallNode(atype, NULL, TypeRawPtr::BOTTOM)
1209 {
1210   init_class_id(Class_Allocate);
1211   init_flags(Flag_is_macro);
1212   _is_scalar_replaceable = false;
1213   _is_non_escaping = false;
1214   Node *topnode = C->top();
1215 
1216   init_req( TypeFunc::Control  , ctrl );
1217   init_req( TypeFunc::I_O      , abio );
1218   init_req( TypeFunc::Memory   , mem );
1219   init_req( TypeFunc::ReturnAdr, topnode );
1220   init_req( TypeFunc::FramePtr , topnode );
1221   init_req( AllocSize          , size);
1222   init_req( KlassNode          , klass_node);
1223   init_req( InitialTest        , initial_test);
1224   init_req( ALength            , topnode);
1225   C->add_macro_node(this);
1226 }
1227 
1228 //=============================================================================
1229 Node* AllocateArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1230   if (remove_dead_region(phase, can_reshape))  return this;
1231   // Don't bother trying to transform a dead node
1232   if (in(0) && in(0)->is_top())  return NULL;
1233 
1234   const Type* type = phase->type(Ideal_length());
1235   if (type->isa_int() && type->is_int()->_hi < 0) {
1236     if (can_reshape) {
1237       PhaseIterGVN *igvn = phase->is_IterGVN();
1238       // Unreachable fall through path (negative array length),
1239       // the allocation can only throw so disconnect it.
1240       Node* proj = proj_out(TypeFunc::Control);
1241       Node* catchproj = NULL;
1242       if (proj != NULL) {
1243         for (DUIterator_Fast imax, i = proj->fast_outs(imax); i < imax; i++) {
1244           Node *cn = proj->fast_out(i);
1245           if (cn->is_Catch()) {
1246             catchproj = cn->as_Multi()->proj_out(CatchProjNode::fall_through_index);
1247             break;
1248           }
1249         }
1250       }
1251       if (catchproj != NULL && catchproj->outcnt() > 0 &&
1252           (catchproj->outcnt() > 1 ||
1253            catchproj->unique_out()->Opcode() != Op_Halt)) {
1254         assert(catchproj->is_CatchProj(), "must be a CatchProjNode");
1255         Node* nproj = catchproj->clone();
1256         igvn->register_new_node_with_optimizer(nproj);
1257 
1258         Node *frame = new (phase->C) ParmNode( phase->C->start(), TypeFunc::FramePtr );
1259         frame = phase->transform(frame);
1260         // Halt & Catch Fire
1261         Node *halt = new (phase->C) HaltNode( nproj, frame );
1262         phase->C->root()->add_req(halt);
1263         phase->transform(halt);
1264 
1265         igvn->replace_node(catchproj, phase->C->top());
1266         return this;
1267       }
1268     } else {
1269       // Can't correct it during regular GVN so register for IGVN
1270       phase->C->record_for_igvn(this);
1271     }
1272   }
1273   return NULL;
1274 }
1275 
1276 // Retrieve the length from the AllocateArrayNode. Narrow the type with a
1277 // CastII, if appropriate.  If we are not allowed to create new nodes, and
1278 // a CastII is appropriate, return NULL.
1279 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseTransform *phase, bool allow_new_nodes) {
1280   Node *length = in(AllocateNode::ALength);
1281   assert(length != NULL, "length is not null");
1282 
1283   const TypeInt* length_type = phase->find_int_type(length);
1284   const TypeAryPtr* ary_type = oop_type->isa_aryptr();
1285 
1286   if (ary_type != NULL && length_type != NULL) {
1287     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);
1288     if (narrow_length_type != length_type) {
1289       // Assert one of:
1290       //   - the narrow_length is 0
1291       //   - the narrow_length is not wider than length
1292       assert(narrow_length_type == TypeInt::ZERO ||
1293              length_type->is_con() && narrow_length_type->is_con() &&
1294                 (narrow_length_type->_hi <= length_type->_lo) ||
1295              (narrow_length_type->_hi <= length_type->_hi &&
1296               narrow_length_type->_lo >= length_type->_lo),
1297              "narrow type must be narrower than length type");
1298 
1299       // Return NULL if new nodes are not allowed
1300       if (!allow_new_nodes) return NULL;
1301       // Create a cast which is control dependent on the initialization to
1302       // propagate the fact that the array length must be positive.
1303       length = new (phase->C) CastIINode(length, narrow_length_type);
1304       length->set_req(0, initialization()->proj_out(0));
1305     }
1306   }
1307 
1308   return length;
1309 }
1310 
1311 //=============================================================================
1312 uint LockNode::size_of() const { return sizeof(*this); }
1313 
1314 // Redundant lock elimination
1315 //
1316 // There are various patterns of locking where we release and
1317 // immediately reacquire a lock in a piece of code where no operations
1318 // occur in between that would be observable.  In those cases we can
1319 // skip releasing and reacquiring the lock without violating any
1320 // fairness requirements.  Doing this around a loop could cause a lock
1321 // to be held for a very long time so we concentrate on non-looping
1322 // control flow.  We also require that the operations are fully
1323 // redundant meaning that we don't introduce new lock operations on
1324 // some paths so to be able to eliminate it on others ala PRE.  This
1325 // would probably require some more extensive graph manipulation to
1326 // guarantee that the memory edges were all handled correctly.
1327 //
1328 // Assuming p is a simple predicate which can't trap in any way and s
1329 // is a synchronized method consider this code:
1330 //
1331 //   s();
1332 //   if (p)
1333 //     s();
1334 //   else
1335 //     s();
1336 //   s();
1337 //
1338 // 1. The unlocks of the first call to s can be eliminated if the
1339 // locks inside the then and else branches are eliminated.
1340 //
1341 // 2. The unlocks of the then and else branches can be eliminated if
1342 // the lock of the final call to s is eliminated.
1343 //
1344 // Either of these cases subsumes the simple case of sequential control flow
1345 //
1346 // Addtionally we can eliminate versions without the else case:
1347 //
1348 //   s();
1349 //   if (p)
1350 //     s();
1351 //   s();
1352 //
1353 // 3. In this case we eliminate the unlock of the first s, the lock
1354 // and unlock in the then case and the lock in the final s.
1355 //
1356 // Note also that in all these cases the then/else pieces don't have
1357 // to be trivial as long as they begin and end with synchronization
1358 // operations.
1359 //
1360 //   s();
1361 //   if (p)
1362 //     s();
1363 //     f();
1364 //     s();
1365 //   s();
1366 //
1367 // The code will work properly for this case, leaving in the unlock
1368 // before the call to f and the relock after it.
1369 //
1370 // A potentially interesting case which isn't handled here is when the
1371 // locking is partially redundant.
1372 //
1373 //   s();
1374 //   if (p)
1375 //     s();
1376 //
1377 // This could be eliminated putting unlocking on the else case and
1378 // eliminating the first unlock and the lock in the then side.
1379 // Alternatively the unlock could be moved out of the then side so it
1380 // was after the merge and the first unlock and second lock
1381 // eliminated.  This might require less manipulation of the memory
1382 // state to get correct.
1383 //
1384 // Additionally we might allow work between a unlock and lock before
1385 // giving up eliminating the locks.  The current code disallows any
1386 // conditional control flow between these operations.  A formulation
1387 // similar to partial redundancy elimination computing the
1388 // availability of unlocking and the anticipatability of locking at a
1389 // program point would allow detection of fully redundant locking with
1390 // some amount of work in between.  I'm not sure how often I really
1391 // think that would occur though.  Most of the cases I've seen
1392 // indicate it's likely non-trivial work would occur in between.
1393 // There may be other more complicated constructs where we could
1394 // eliminate locking but I haven't seen any others appear as hot or
1395 // interesting.
1396 //
1397 // Locking and unlocking have a canonical form in ideal that looks
1398 // roughly like this:
1399 //
1400 //              <obj>
1401 //                | \\------+
1402 //                |  \       \
1403 //                | BoxLock   \
1404 //                |  |   |     \
1405 //                |  |    \     \
1406 //                |  |   FastLock
1407 //                |  |   /
1408 //                |  |  /
1409 //                |  |  |
1410 //
1411 //               Lock
1412 //                |
1413 //            Proj #0
1414 //                |
1415 //            MembarAcquire
1416 //                |
1417 //            Proj #0
1418 //
1419 //            MembarRelease
1420 //                |
1421 //            Proj #0
1422 //                |
1423 //              Unlock
1424 //                |
1425 //            Proj #0
1426 //
1427 //
1428 // This code proceeds by processing Lock nodes during PhaseIterGVN
1429 // and searching back through its control for the proper code
1430 // patterns.  Once it finds a set of lock and unlock operations to
1431 // eliminate they are marked as eliminatable which causes the
1432 // expansion of the Lock and Unlock macro nodes to make the operation a NOP
1433 //
1434 //=============================================================================
1435 
1436 //
1437 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:
1438 //   - copy regions.  (These may not have been optimized away yet.)
1439 //   - eliminated locking nodes
1440 //
1441 static Node *next_control(Node *ctrl) {
1442   if (ctrl == NULL)
1443     return NULL;
1444   while (1) {
1445     if (ctrl->is_Region()) {
1446       RegionNode *r = ctrl->as_Region();
1447       Node *n = r->is_copy();
1448       if (n == NULL)
1449         break;  // hit a region, return it
1450       else
1451         ctrl = n;
1452     } else if (ctrl->is_Proj()) {
1453       Node *in0 = ctrl->in(0);
1454       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {
1455         ctrl = in0->in(0);
1456       } else {
1457         break;
1458       }
1459     } else {
1460       break; // found an interesting control
1461     }
1462   }
1463   return ctrl;
1464 }
1465 //
1466 // Given a control, see if it's the control projection of an Unlock which
1467 // operating on the same object as lock.
1468 //
1469 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,
1470                                             GrowableArray<AbstractLockNode*> &lock_ops) {
1471   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : NULL;
1472   if (ctrl_proj != NULL && ctrl_proj->_con == TypeFunc::Control) {
1473     Node *n = ctrl_proj->in(0);
1474     if (n != NULL && n->is_Unlock()) {
1475       UnlockNode *unlock = n->as_Unlock();
1476       if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1477           BoxLockNode::same_slot(lock->box_node(), unlock->box_node()) &&
1478           !unlock->is_eliminated()) {
1479         lock_ops.append(unlock);
1480         return true;
1481       }
1482     }
1483   }
1484   return false;
1485 }
1486 
1487 //
1488 // Find the lock matching an unlock.  Returns null if a safepoint
1489 // or complicated control is encountered first.
1490 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {
1491   LockNode *lock_result = NULL;
1492   // find the matching lock, or an intervening safepoint
1493   Node *ctrl = next_control(unlock->in(0));
1494   while (1) {
1495     assert(ctrl != NULL, "invalid control graph");
1496     assert(!ctrl->is_Start(), "missing lock for unlock");
1497     if (ctrl->is_top()) break;  // dead control path
1498     if (ctrl->is_Proj()) ctrl = ctrl->in(0);
1499     if (ctrl->is_SafePoint()) {
1500         break;  // found a safepoint (may be the lock we are searching for)
1501     } else if (ctrl->is_Region()) {
1502       // Check for a simple diamond pattern.  Punt on anything more complicated
1503       if (ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(2) != NULL) {
1504         Node *in1 = next_control(ctrl->in(1));
1505         Node *in2 = next_control(ctrl->in(2));
1506         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||
1507              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {
1508           ctrl = next_control(in1->in(0)->in(0));
1509         } else {
1510           break;
1511         }
1512       } else {
1513         break;
1514       }
1515     } else {
1516       ctrl = next_control(ctrl->in(0));  // keep searching
1517     }
1518   }
1519   if (ctrl->is_Lock()) {
1520     LockNode *lock = ctrl->as_Lock();
1521     if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1522         BoxLockNode::same_slot(lock->box_node(), unlock->box_node())) {
1523       lock_result = lock;
1524     }
1525   }
1526   return lock_result;
1527 }
1528 
1529 // This code corresponds to case 3 above.
1530 
1531 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,
1532                                                        GrowableArray<AbstractLockNode*> &lock_ops) {
1533   Node* if_node = node->in(0);
1534   bool  if_true = node->is_IfTrue();
1535 
1536   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {
1537     Node *lock_ctrl = next_control(if_node->in(0));
1538     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {
1539       Node* lock1_node = NULL;
1540       ProjNode* proj = if_node->as_If()->proj_out(!if_true);
1541       if (if_true) {
1542         if (proj->is_IfFalse() && proj->outcnt() == 1) {
1543           lock1_node = proj->unique_out();
1544         }
1545       } else {
1546         if (proj->is_IfTrue() && proj->outcnt() == 1) {
1547           lock1_node = proj->unique_out();
1548         }
1549       }
1550       if (lock1_node != NULL && lock1_node->is_Lock()) {
1551         LockNode *lock1 = lock1_node->as_Lock();
1552         if (lock->obj_node()->eqv_uncast(lock1->obj_node()) &&
1553             BoxLockNode::same_slot(lock->box_node(), lock1->box_node()) &&
1554             !lock1->is_eliminated()) {
1555           lock_ops.append(lock1);
1556           return true;
1557         }
1558       }
1559     }
1560   }
1561 
1562   lock_ops.trunc_to(0);
1563   return false;
1564 }
1565 
1566 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,
1567                                GrowableArray<AbstractLockNode*> &lock_ops) {
1568   // check each control merging at this point for a matching unlock.
1569   // in(0) should be self edge so skip it.
1570   for (int i = 1; i < (int)region->req(); i++) {
1571     Node *in_node = next_control(region->in(i));
1572     if (in_node != NULL) {
1573       if (find_matching_unlock(in_node, lock, lock_ops)) {
1574         // found a match so keep on checking.
1575         continue;
1576       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {
1577         continue;
1578       }
1579 
1580       // If we fall through to here then it was some kind of node we
1581       // don't understand or there wasn't a matching unlock, so give
1582       // up trying to merge locks.
1583       lock_ops.trunc_to(0);
1584       return false;
1585     }
1586   }
1587   return true;
1588 
1589 }
1590 
1591 #ifndef PRODUCT
1592 //
1593 // Create a counter which counts the number of times this lock is acquired
1594 //
1595 void AbstractLockNode::create_lock_counter(JVMState* state) {
1596   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);
1597 }
1598 
1599 void AbstractLockNode::set_eliminated_lock_counter() {
1600   if (_counter) {
1601     // Update the counter to indicate that this lock was eliminated.
1602     // The counter update code will stay around even though the
1603     // optimizer will eliminate the lock operation itself.
1604     _counter->set_tag(NamedCounter::EliminatedLockCounter);
1605   }
1606 }
1607 #endif
1608 
1609 //=============================================================================
1610 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1611 
1612   // perform any generic optimizations first (returns 'this' or NULL)
1613   Node *result = SafePointNode::Ideal(phase, can_reshape);
1614   if (result != NULL)  return result;
1615   // Don't bother trying to transform a dead node
1616   if (in(0) && in(0)->is_top())  return NULL;
1617 
1618   // Now see if we can optimize away this lock.  We don't actually
1619   // remove the locking here, we simply set the _eliminate flag which
1620   // prevents macro expansion from expanding the lock.  Since we don't
1621   // modify the graph, the value returned from this function is the
1622   // one computed above.
1623   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1624     //
1625     // If we are locking an unescaped object, the lock/unlock is unnecessary
1626     //
1627     ConnectionGraph *cgr = phase->C->congraph();
1628     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1629       assert(!is_eliminated() || is_coarsened(), "sanity");
1630       // The lock could be marked eliminated by lock coarsening
1631       // code during first IGVN before EA. Replace coarsened flag
1632       // to eliminate all associated locks/unlocks.
1633       this->set_non_esc_obj();
1634       return result;
1635     }
1636 
1637     //
1638     // Try lock coarsening
1639     //
1640     PhaseIterGVN* iter = phase->is_IterGVN();
1641     if (iter != NULL && !is_eliminated()) {
1642 
1643       GrowableArray<AbstractLockNode*>   lock_ops;
1644 
1645       Node *ctrl = next_control(in(0));
1646 
1647       // now search back for a matching Unlock
1648       if (find_matching_unlock(ctrl, this, lock_ops)) {
1649         // found an unlock directly preceding this lock.  This is the
1650         // case of single unlock directly control dependent on a
1651         // single lock which is the trivial version of case 1 or 2.
1652       } else if (ctrl->is_Region() ) {
1653         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {
1654         // found lock preceded by multiple unlocks along all paths
1655         // joining at this point which is case 3 in description above.
1656         }
1657       } else {
1658         // see if this lock comes from either half of an if and the
1659         // predecessors merges unlocks and the other half of the if
1660         // performs a lock.
1661         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {
1662           // found unlock splitting to an if with locks on both branches.
1663         }
1664       }
1665 
1666       if (lock_ops.length() > 0) {
1667         // add ourselves to the list of locks to be eliminated.
1668         lock_ops.append(this);
1669 
1670   #ifndef PRODUCT
1671         if (PrintEliminateLocks) {
1672           int locks = 0;
1673           int unlocks = 0;
1674           for (int i = 0; i < lock_ops.length(); i++) {
1675             AbstractLockNode* lock = lock_ops.at(i);
1676             if (lock->Opcode() == Op_Lock)
1677               locks++;
1678             else
1679               unlocks++;
1680             if (Verbose) {
1681               lock->dump(1);
1682             }
1683           }
1684           tty->print_cr("***Eliminated %d unlocks and %d locks", unlocks, locks);
1685         }
1686   #endif
1687 
1688         // for each of the identified locks, mark them
1689         // as eliminatable
1690         for (int i = 0; i < lock_ops.length(); i++) {
1691           AbstractLockNode* lock = lock_ops.at(i);
1692 
1693           // Mark it eliminated by coarsening and update any counters
1694           lock->set_coarsened();
1695         }
1696       } else if (ctrl->is_Region() &&
1697                  iter->_worklist.member(ctrl)) {
1698         // We weren't able to find any opportunities but the region this
1699         // lock is control dependent on hasn't been processed yet so put
1700         // this lock back on the worklist so we can check again once any
1701         // region simplification has occurred.
1702         iter->_worklist.push(this);
1703       }
1704     }
1705   }
1706 
1707   return result;
1708 }
1709 
1710 //=============================================================================
1711 bool LockNode::is_nested_lock_region() {
1712   BoxLockNode* box = box_node()->as_BoxLock();
1713   int stk_slot = box->stack_slot();
1714   if (stk_slot <= 0)
1715     return false; // External lock or it is not Box (Phi node).
1716 
1717   // Ignore complex cases: merged locks or multiple locks.
1718   Node* obj = obj_node();
1719   LockNode* unique_lock = NULL;
1720   if (!box->is_simple_lock_region(&unique_lock, obj) ||
1721       (unique_lock != this)) {
1722     return false;
1723   }
1724 
1725   // Look for external lock for the same object.
1726   SafePointNode* sfn = this->as_SafePoint();
1727   JVMState* youngest_jvms = sfn->jvms();
1728   int max_depth = youngest_jvms->depth();
1729   for (int depth = 1; depth <= max_depth; depth++) {
1730     JVMState* jvms = youngest_jvms->of_depth(depth);
1731     int num_mon  = jvms->nof_monitors();
1732     // Loop over monitors
1733     for (int idx = 0; idx < num_mon; idx++) {
1734       Node* obj_node = sfn->monitor_obj(jvms, idx);
1735       BoxLockNode* box_node = sfn->monitor_box(jvms, idx)->as_BoxLock();
1736       if ((box_node->stack_slot() < stk_slot) && obj_node->eqv_uncast(obj)) {
1737         return true;
1738       }
1739     }
1740   }
1741   return false;
1742 }
1743 
1744 //=============================================================================
1745 uint UnlockNode::size_of() const { return sizeof(*this); }
1746 
1747 //=============================================================================
1748 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1749 
1750   // perform any generic optimizations first (returns 'this' or NULL)
1751   Node *result = SafePointNode::Ideal(phase, can_reshape);
1752   if (result != NULL)  return result;
1753   // Don't bother trying to transform a dead node
1754   if (in(0) && in(0)->is_top())  return NULL;
1755 
1756   // Now see if we can optimize away this unlock.  We don't actually
1757   // remove the unlocking here, we simply set the _eliminate flag which
1758   // prevents macro expansion from expanding the unlock.  Since we don't
1759   // modify the graph, the value returned from this function is the
1760   // one computed above.
1761   // Escape state is defined after Parse phase.
1762   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1763     //
1764     // If we are unlocking an unescaped object, the lock/unlock is unnecessary.
1765     //
1766     ConnectionGraph *cgr = phase->C->congraph();
1767     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1768       assert(!is_eliminated() || is_coarsened(), "sanity");
1769       // The lock could be marked eliminated by lock coarsening
1770       // code during first IGVN before EA. Replace coarsened flag
1771       // to eliminate all associated locks/unlocks.
1772       this->set_non_esc_obj();
1773     }
1774   }
1775   return result;
1776 }