1 /*
   2  * Copyright (c) 1997, 2014, 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 MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
  78   case TypeFunc::FramePtr:
  79     return new MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);
  80   case TypeFunc::ReturnAdr:
  81     return new 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 ConNode(Type::TOP);
  88       uint ideal_reg = t->ideal_reg();
  89       RegMask &rm = match->_calling_convention_mask[parm_num];
  90       return new 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("%s", 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,p2i(t->isa_oopptr()->const_oop()));
 352       break;
 353     case Type::KlassPtr:
 354       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_klassptr()->klass()));
 355       break;
 356     case Type::MetadataPtr:
 357       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_metadataptr()->metadata()));
 358       break;
 359     case Type::NarrowOop:
 360       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,p2i(t->make_ptr()->isa_oopptr()->const_oop()));
 361       break;
 362     case Type::RawPtr:
 363       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,p2i(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,(int64_t)(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->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->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 // Mirror the stack size calculation in the deopt code
 612 // How much stack space would we need at this point in the program in
 613 // case of deoptimization?
 614 int JVMState::interpreter_frame_size() const {
 615   const JVMState* jvms = this;
 616   int size = 0;
 617   int callee_parameters = 0;
 618   int callee_locals = 0;
 619   int extra_args = method()->max_stack() - stk_size();
 620 
 621   while (jvms != NULL) {
 622     int locks = jvms->nof_monitors();
 623     int temps = jvms->stk_size();
 624     bool is_top_frame = (jvms == this);
 625     ciMethod* method = jvms->method();
 626 
 627     int frame_size = BytesPerWord * Interpreter::size_activation(method->max_stack(),
 628                                                                  temps + callee_parameters,
 629                                                                  extra_args,
 630                                                                  locks,
 631                                                                  callee_parameters,
 632                                                                  callee_locals,
 633                                                                  is_top_frame);
 634     size += frame_size;
 635 
 636     callee_parameters = method->size_of_parameters();
 637     callee_locals = method->max_locals();
 638     extra_args = 0;
 639     jvms = jvms->caller();
 640   }
 641   return size + Deoptimization::last_frame_adjust(0, callee_locals) * BytesPerWord;
 642 }
 643 
 644 //=============================================================================
 645 uint CallNode::cmp( const Node &n ) const
 646 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }
 647 #ifndef PRODUCT
 648 void CallNode::dump_req(outputStream *st) const {
 649   // Dump the required inputs, enclosed in '(' and ')'
 650   uint i;                       // Exit value of loop
 651   for (i = 0; i < req(); i++) {    // For all required inputs
 652     if (i == TypeFunc::Parms) st->print("(");
 653     if (in(i)) st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
 654     else st->print("_ ");
 655   }
 656   st->print(")");
 657 }
 658 
 659 void CallNode::dump_spec(outputStream *st) const {
 660   st->print(" ");
 661   tf()->dump_on(st);
 662   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);
 663   if (jvms() != NULL)  jvms()->dump_spec(st);
 664 }
 665 #endif
 666 
 667 const Type *CallNode::bottom_type() const { return tf()->range(); }
 668 const Type *CallNode::Value(PhaseTransform *phase) const {
 669   if (phase->type(in(0)) == Type::TOP)  return Type::TOP;
 670   return tf()->range();
 671 }
 672 
 673 //------------------------------calling_convention-----------------------------
 674 void CallNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 675   // Use the standard compiler calling convention
 676   Matcher::calling_convention( sig_bt, parm_regs, argcnt, true );
 677 }
 678 
 679 
 680 //------------------------------match------------------------------------------
 681 // Construct projections for control, I/O, memory-fields, ..., and
 682 // return result(s) along with their RegMask info
 683 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {
 684   switch (proj->_con) {
 685   case TypeFunc::Control:
 686   case TypeFunc::I_O:
 687   case TypeFunc::Memory:
 688     return new MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
 689 
 690   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns
 691     assert(tf()->range()->field_at(TypeFunc::Parms+1) == Type::HALF, "");
 692     // 2nd half of doubles and longs
 693     return new MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);
 694 
 695   case TypeFunc::Parms: {       // Normal returns
 696     uint ideal_reg = tf()->range()->field_at(TypeFunc::Parms)->ideal_reg();
 697     OptoRegPair regs = is_CallRuntime()
 698       ? match->c_return_value(ideal_reg,true)  // Calls into C runtime
 699       : match->  return_value(ideal_reg,true); // Calls into compiled Java code
 700     RegMask rm = RegMask(regs.first());
 701     if( OptoReg::is_valid(regs.second()) )
 702       rm.Insert( regs.second() );
 703     return new MachProjNode(this,proj->_con,rm,ideal_reg);
 704   }
 705 
 706   case TypeFunc::ReturnAdr:
 707   case TypeFunc::FramePtr:
 708   default:
 709     ShouldNotReachHere();
 710   }
 711   return NULL;
 712 }
 713 
 714 // Do we Match on this edge index or not?  Match no edges
 715 uint CallNode::match_edge(uint idx) const {
 716   return 0;
 717 }
 718 
 719 //
 720 // Determine whether the call could modify the field of the specified
 721 // instance at the specified offset.
 722 //
 723 bool CallNode::may_modify(const TypeOopPtr *t_oop, PhaseTransform *phase) {
 724   assert((t_oop != NULL), "sanity");
 725   if (t_oop->is_known_instance()) {
 726     // The instance_id is set only for scalar-replaceable allocations which
 727     // are not passed as arguments according to Escape Analysis.
 728     return false;
 729   }
 730   if (t_oop->is_ptr_to_boxed_value()) {
 731     ciKlass* boxing_klass = t_oop->klass();
 732     if (is_CallStaticJava() && as_CallStaticJava()->is_boxing_method()) {
 733       // Skip unrelated boxing methods.
 734       Node* proj = proj_out(TypeFunc::Parms);
 735       if ((proj == NULL) || (phase->type(proj)->is_instptr()->klass() != boxing_klass)) {
 736         return false;
 737       }
 738     }
 739     if (is_CallJava() && as_CallJava()->method() != NULL) {
 740       ciMethod* meth = as_CallJava()->method();
 741       if (meth->is_accessor()) {
 742         return false;
 743       }
 744       // May modify (by reflection) if an boxing object is passed
 745       // as argument or returned.
 746       if (returns_pointer() && (proj_out(TypeFunc::Parms) != NULL)) {
 747         Node* proj = proj_out(TypeFunc::Parms);
 748         const TypeInstPtr* inst_t = phase->type(proj)->isa_instptr();
 749         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 750                                  (inst_t->klass() == boxing_klass))) {
 751           return true;
 752         }
 753       }
 754       const TypeTuple* d = tf()->domain();
 755       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 756         const TypeInstPtr* inst_t = d->field_at(i)->isa_instptr();
 757         if ((inst_t != NULL) && (!inst_t->klass_is_exact() ||
 758                                  (inst_t->klass() == boxing_klass))) {
 759           return true;
 760         }
 761       }
 762       return false;
 763     }
 764   }
 765   return true;
 766 }
 767 
 768 // Does this call have a direct reference to n other than debug information?
 769 bool CallNode::has_non_debug_use(Node *n) {
 770   const TypeTuple * d = tf()->domain();
 771   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 772     Node *arg = in(i);
 773     if (arg == n) {
 774       return true;
 775     }
 776   }
 777   return false;
 778 }
 779 
 780 // Returns the unique CheckCastPP of a call
 781 // or 'this' if there are several CheckCastPP
 782 // or returns NULL if there is no one.
 783 Node *CallNode::result_cast() {
 784   Node *cast = NULL;
 785 
 786   Node *p = proj_out(TypeFunc::Parms);
 787   if (p == NULL)
 788     return NULL;
 789 
 790   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {
 791     Node *use = p->fast_out(i);
 792     if (use->is_CheckCastPP()) {
 793       if (cast != NULL) {
 794         return this;  // more than 1 CheckCastPP
 795       }
 796       cast = use;
 797     }
 798   }
 799   return cast;
 800 }
 801 
 802 
 803 void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj) {
 804   projs->fallthrough_proj      = NULL;
 805   projs->fallthrough_catchproj = NULL;
 806   projs->fallthrough_ioproj    = NULL;
 807   projs->catchall_ioproj       = NULL;
 808   projs->catchall_catchproj    = NULL;
 809   projs->fallthrough_memproj   = NULL;
 810   projs->catchall_memproj      = NULL;
 811   projs->resproj               = NULL;
 812   projs->exobj                 = NULL;
 813 
 814   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 815     ProjNode *pn = fast_out(i)->as_Proj();
 816     if (pn->outcnt() == 0) continue;
 817     switch (pn->_con) {
 818     case TypeFunc::Control:
 819       {
 820         // For Control (fallthrough) and I_O (catch_all_index) we have CatchProj -> Catch -> Proj
 821         projs->fallthrough_proj = pn;
 822         DUIterator_Fast jmax, j = pn->fast_outs(jmax);
 823         const Node *cn = pn->fast_out(j);
 824         if (cn->is_Catch()) {
 825           ProjNode *cpn = NULL;
 826           for (DUIterator_Fast kmax, k = cn->fast_outs(kmax); k < kmax; k++) {
 827             cpn = cn->fast_out(k)->as_Proj();
 828             assert(cpn->is_CatchProj(), "must be a CatchProjNode");
 829             if (cpn->_con == CatchProjNode::fall_through_index)
 830               projs->fallthrough_catchproj = cpn;
 831             else {
 832               assert(cpn->_con == CatchProjNode::catch_all_index, "must be correct index.");
 833               projs->catchall_catchproj = cpn;
 834             }
 835           }
 836         }
 837         break;
 838       }
 839     case TypeFunc::I_O:
 840       if (pn->_is_io_use)
 841         projs->catchall_ioproj = pn;
 842       else
 843         projs->fallthrough_ioproj = pn;
 844       for (DUIterator j = pn->outs(); pn->has_out(j); j++) {
 845         Node* e = pn->out(j);
 846         if (e->Opcode() == Op_CreateEx && e->in(0)->is_CatchProj() && e->outcnt() > 0) {
 847           assert(projs->exobj == NULL, "only one");
 848           projs->exobj = e;
 849         }
 850       }
 851       break;
 852     case TypeFunc::Memory:
 853       if (pn->_is_io_use)
 854         projs->catchall_memproj = pn;
 855       else
 856         projs->fallthrough_memproj = pn;
 857       break;
 858     case TypeFunc::Parms:
 859       projs->resproj = pn;
 860       break;
 861     default:
 862       assert(false, "unexpected projection from allocation node.");
 863     }
 864   }
 865 
 866   // The resproj may not exist because the result couuld be ignored
 867   // and the exception object may not exist if an exception handler
 868   // swallows the exception but all the other must exist and be found.
 869   assert(projs->fallthrough_proj      != NULL, "must be found");
 870   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_catchproj != NULL, "must be found");
 871   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_memproj   != NULL, "must be found");
 872   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_ioproj    != NULL, "must be found");
 873   assert(Compile::current()->inlining_incrementally() || projs->catchall_catchproj    != NULL, "must be found");
 874   if (separate_io_proj) {
 875     assert(Compile::current()->inlining_incrementally() || projs->catchall_memproj    != NULL, "must be found");
 876     assert(Compile::current()->inlining_incrementally() || projs->catchall_ioproj     != NULL, "must be found");
 877   }
 878 }
 879 
 880 Node *CallNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 881   CallGenerator* cg = generator();
 882   if (can_reshape && cg != NULL && cg->is_mh_late_inline() && !cg->already_attempted()) {
 883     // Check whether this MH handle call becomes a candidate for inlining
 884     ciMethod* callee = cg->method();
 885     vmIntrinsics::ID iid = callee->intrinsic_id();
 886     if (iid == vmIntrinsics::_invokeBasic) {
 887       if (in(TypeFunc::Parms)->Opcode() == Op_ConP) {
 888         phase->C->prepend_late_inline(cg);
 889         set_generator(NULL);
 890       }
 891     } else {
 892       assert(callee->has_member_arg(), "wrong type of call?");
 893       if (in(TypeFunc::Parms + callee->arg_size() - 1)->Opcode() == Op_ConP) {
 894         phase->C->prepend_late_inline(cg);
 895         set_generator(NULL);
 896       }
 897     }
 898   }
 899   return SafePointNode::Ideal(phase, can_reshape);
 900 }
 901 
 902 
 903 //=============================================================================
 904 uint CallJavaNode::size_of() const { return sizeof(*this); }
 905 uint CallJavaNode::cmp( const Node &n ) const {
 906   CallJavaNode &call = (CallJavaNode&)n;
 907   return CallNode::cmp(call) && _method == call._method;
 908 }
 909 #ifndef PRODUCT
 910 void CallJavaNode::dump_spec(outputStream *st) const {
 911   if( _method ) _method->print_short_name(st);
 912   CallNode::dump_spec(st);
 913 }
 914 #endif
 915 
 916 //=============================================================================
 917 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }
 918 uint CallStaticJavaNode::cmp( const Node &n ) const {
 919   CallStaticJavaNode &call = (CallStaticJavaNode&)n;
 920   return CallJavaNode::cmp(call);
 921 }
 922 
 923 //----------------------------uncommon_trap_request----------------------------
 924 // If this is an uncommon trap, return the request code, else zero.
 925 int CallStaticJavaNode::uncommon_trap_request() const {
 926   if (_name != NULL && !strcmp(_name, "uncommon_trap")) {
 927     return extract_uncommon_trap_request(this);
 928   }
 929   return 0;
 930 }
 931 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {
 932 #ifndef PRODUCT
 933   if (!(call->req() > TypeFunc::Parms &&
 934         call->in(TypeFunc::Parms) != NULL &&
 935         call->in(TypeFunc::Parms)->is_Con())) {
 936     assert(in_dump() != 0, "OK if dumping");
 937     tty->print("[bad uncommon trap]");
 938     return 0;
 939   }
 940 #endif
 941   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();
 942 }
 943 
 944 #ifndef PRODUCT
 945 void CallStaticJavaNode::dump_spec(outputStream *st) const {
 946   st->print("# Static ");
 947   if (_name != NULL) {
 948     st->print("%s", _name);
 949     int trap_req = uncommon_trap_request();
 950     if (trap_req != 0) {
 951       char buf[100];
 952       st->print("(%s)",
 953                  Deoptimization::format_trap_request(buf, sizeof(buf),
 954                                                      trap_req));
 955     }
 956     st->print(" ");
 957   }
 958   CallJavaNode::dump_spec(st);
 959 }
 960 #endif
 961 
 962 //=============================================================================
 963 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }
 964 uint CallDynamicJavaNode::cmp( const Node &n ) const {
 965   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;
 966   return CallJavaNode::cmp(call);
 967 }
 968 #ifndef PRODUCT
 969 void CallDynamicJavaNode::dump_spec(outputStream *st) const {
 970   st->print("# Dynamic ");
 971   CallJavaNode::dump_spec(st);
 972 }
 973 #endif
 974 
 975 //=============================================================================
 976 uint CallRuntimeNode::size_of() const { return sizeof(*this); }
 977 uint CallRuntimeNode::cmp( const Node &n ) const {
 978   CallRuntimeNode &call = (CallRuntimeNode&)n;
 979   return CallNode::cmp(call) && !strcmp(_name,call._name);
 980 }
 981 #ifndef PRODUCT
 982 void CallRuntimeNode::dump_spec(outputStream *st) const {
 983   st->print("# ");
 984   st->print("%s", _name);
 985   CallNode::dump_spec(st);
 986 }
 987 #endif
 988 
 989 //------------------------------calling_convention-----------------------------
 990 void CallRuntimeNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {
 991   Matcher::c_calling_convention( sig_bt, parm_regs, argcnt );
 992 }
 993 
 994 //=============================================================================
 995 //------------------------------calling_convention-----------------------------
 996 
 997 
 998 //=============================================================================
 999 #ifndef PRODUCT
1000 void CallLeafNode::dump_spec(outputStream *st) const {
1001   st->print("# ");
1002   st->print("%s", _name);
1003   CallNode::dump_spec(st);
1004 }
1005 #endif
1006 
1007 //=============================================================================
1008 
1009 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {
1010   assert(verify_jvms(jvms), "jvms must match");
1011   int loc = jvms->locoff() + idx;
1012   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {
1013     // If current local idx is top then local idx - 1 could
1014     // be a long/double that needs to be killed since top could
1015     // represent the 2nd half ofthe long/double.
1016     uint ideal = in(loc -1)->ideal_reg();
1017     if (ideal == Op_RegD || ideal == Op_RegL) {
1018       // set other (low index) half to top
1019       set_req(loc - 1, in(loc));
1020     }
1021   }
1022   set_req(loc, c);
1023 }
1024 
1025 uint SafePointNode::size_of() const { return sizeof(*this); }
1026 uint SafePointNode::cmp( const Node &n ) const {
1027   return (&n == this);          // Always fail except on self
1028 }
1029 
1030 //-------------------------set_next_exception----------------------------------
1031 void SafePointNode::set_next_exception(SafePointNode* n) {
1032   assert(n == NULL || n->Opcode() == Op_SafePoint, "correct value for next_exception");
1033   if (len() == req()) {
1034     if (n != NULL)  add_prec(n);
1035   } else {
1036     set_prec(req(), n);
1037   }
1038 }
1039 
1040 
1041 //----------------------------next_exception-----------------------------------
1042 SafePointNode* SafePointNode::next_exception() const {
1043   if (len() == req()) {
1044     return NULL;
1045   } else {
1046     Node* n = in(req());
1047     assert(n == NULL || n->Opcode() == Op_SafePoint, "no other uses of prec edges");
1048     return (SafePointNode*) n;
1049   }
1050 }
1051 
1052 
1053 //------------------------------Ideal------------------------------------------
1054 // Skip over any collapsed Regions
1055 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1056   return remove_dead_region(phase, can_reshape) ? this : NULL;
1057 }
1058 
1059 //------------------------------Identity---------------------------------------
1060 // Remove obviously duplicate safepoints
1061 Node *SafePointNode::Identity( PhaseTransform *phase ) {
1062 
1063   // If you have back to back safepoints, remove one
1064   if( in(TypeFunc::Control)->is_SafePoint() )
1065     return in(TypeFunc::Control);
1066 
1067   if( in(0)->is_Proj() ) {
1068     Node *n0 = in(0)->in(0);
1069     // Check if he is a call projection (except Leaf Call)
1070     if( n0->is_Catch() ) {
1071       n0 = n0->in(0)->in(0);
1072       assert( n0->is_Call(), "expect a call here" );
1073     }
1074     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {
1075       // Useless Safepoint, so remove it
1076       return in(TypeFunc::Control);
1077     }
1078   }
1079 
1080   return this;
1081 }
1082 
1083 //------------------------------Value------------------------------------------
1084 const Type *SafePointNode::Value( PhaseTransform *phase ) const {
1085   if( phase->type(in(0)) == Type::TOP ) return Type::TOP;
1086   if( phase->eqv( in(0), this ) ) return Type::TOP; // Dead infinite loop
1087   return Type::CONTROL;
1088 }
1089 
1090 #ifndef PRODUCT
1091 void SafePointNode::dump_spec(outputStream *st) const {
1092   st->print(" SafePoint ");
1093   _replaced_nodes.dump(st);
1094 }
1095 #endif
1096 
1097 const RegMask &SafePointNode::in_RegMask(uint idx) const {
1098   if( idx < TypeFunc::Parms ) return RegMask::Empty;
1099   // Values outside the domain represent debug info
1100   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1101 }
1102 const RegMask &SafePointNode::out_RegMask() const {
1103   return RegMask::Empty;
1104 }
1105 
1106 
1107 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {
1108   assert((int)grow_by > 0, "sanity");
1109   int monoff = jvms->monoff();
1110   int scloff = jvms->scloff();
1111   int endoff = jvms->endoff();
1112   assert(endoff == (int)req(), "no other states or debug info after me");
1113   Node* top = Compile::current()->top();
1114   for (uint i = 0; i < grow_by; i++) {
1115     ins_req(monoff, top);
1116   }
1117   jvms->set_monoff(monoff + grow_by);
1118   jvms->set_scloff(scloff + grow_by);
1119   jvms->set_endoff(endoff + grow_by);
1120 }
1121 
1122 void SafePointNode::push_monitor(const FastLockNode *lock) {
1123   // Add a LockNode, which points to both the original BoxLockNode (the
1124   // stack space for the monitor) and the Object being locked.
1125   const int MonitorEdges = 2;
1126   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1127   assert(req() == jvms()->endoff(), "correct sizing");
1128   int nextmon = jvms()->scloff();
1129   if (GenerateSynchronizationCode) {
1130     ins_req(nextmon,   lock->box_node());
1131     ins_req(nextmon+1, lock->obj_node());
1132   } else {
1133     Node* top = Compile::current()->top();
1134     ins_req(nextmon, top);
1135     ins_req(nextmon, top);
1136   }
1137   jvms()->set_scloff(nextmon + MonitorEdges);
1138   jvms()->set_endoff(req());
1139 }
1140 
1141 void SafePointNode::pop_monitor() {
1142   // Delete last monitor from debug info
1143   debug_only(int num_before_pop = jvms()->nof_monitors());
1144   const int MonitorEdges = 2;
1145   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");
1146   int scloff = jvms()->scloff();
1147   int endoff = jvms()->endoff();
1148   int new_scloff = scloff - MonitorEdges;
1149   int new_endoff = endoff - MonitorEdges;
1150   jvms()->set_scloff(new_scloff);
1151   jvms()->set_endoff(new_endoff);
1152   while (scloff > new_scloff)  del_req_ordered(--scloff);
1153   assert(jvms()->nof_monitors() == num_before_pop-1, "");
1154 }
1155 
1156 Node *SafePointNode::peek_monitor_box() const {
1157   int mon = jvms()->nof_monitors() - 1;
1158   assert(mon >= 0, "most have a monitor");
1159   return monitor_box(jvms(), mon);
1160 }
1161 
1162 Node *SafePointNode::peek_monitor_obj() const {
1163   int mon = jvms()->nof_monitors() - 1;
1164   assert(mon >= 0, "most have a monitor");
1165   return monitor_obj(jvms(), mon);
1166 }
1167 
1168 // Do we Match on this edge index or not?  Match no edges
1169 uint SafePointNode::match_edge(uint idx) const {
1170   if( !needs_polling_address_input() )
1171     return 0;
1172 
1173   return (TypeFunc::Parms == idx);
1174 }
1175 
1176 //==============  SafePointScalarObjectNode  ==============
1177 
1178 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp,
1179 #ifdef ASSERT
1180                                                      AllocateNode* alloc,
1181 #endif
1182                                                      uint first_index,
1183                                                      uint n_fields) :
1184   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.
1185 #ifdef ASSERT
1186   _alloc(alloc),
1187 #endif
1188   _first_index(first_index),
1189   _n_fields(n_fields)
1190 {
1191   init_class_id(Class_SafePointScalarObject);
1192 }
1193 
1194 // Do not allow value-numbering for SafePointScalarObject node.
1195 uint SafePointScalarObjectNode::hash() const { return NO_HASH; }
1196 uint SafePointScalarObjectNode::cmp( const Node &n ) const {
1197   return (&n == this); // Always fail except on self
1198 }
1199 
1200 uint SafePointScalarObjectNode::ideal_reg() const {
1201   return 0; // No matching to machine instruction
1202 }
1203 
1204 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {
1205   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);
1206 }
1207 
1208 const RegMask &SafePointScalarObjectNode::out_RegMask() const {
1209   return RegMask::Empty;
1210 }
1211 
1212 uint SafePointScalarObjectNode::match_edge(uint idx) const {
1213   return 0;
1214 }
1215 
1216 SafePointScalarObjectNode*
1217 SafePointScalarObjectNode::clone(Dict* sosn_map) const {
1218   void* cached = (*sosn_map)[(void*)this];
1219   if (cached != NULL) {
1220     return (SafePointScalarObjectNode*)cached;
1221   }
1222   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();
1223   sosn_map->Insert((void*)this, (void*)res);
1224   return res;
1225 }
1226 
1227 
1228 #ifndef PRODUCT
1229 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {
1230   st->print(" # fields@[%d..%d]", first_index(),
1231              first_index() + n_fields() - 1);
1232 }
1233 
1234 #endif
1235 
1236 //=============================================================================
1237 uint AllocateNode::size_of() const { return sizeof(*this); }
1238 
1239 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,
1240                            Node *ctrl, Node *mem, Node *abio,
1241                            Node *size, Node *klass_node, Node *initial_test)
1242   : CallNode(atype, NULL, TypeRawPtr::BOTTOM)
1243 {
1244   init_class_id(Class_Allocate);
1245   init_flags(Flag_is_macro);
1246   _is_scalar_replaceable = false;
1247   _is_non_escaping = false;
1248   Node *topnode = C->top();
1249 
1250   init_req( TypeFunc::Control  , ctrl );
1251   init_req( TypeFunc::I_O      , abio );
1252   init_req( TypeFunc::Memory   , mem );
1253   init_req( TypeFunc::ReturnAdr, topnode );
1254   init_req( TypeFunc::FramePtr , topnode );
1255   init_req( AllocSize          , size);
1256   init_req( KlassNode          , klass_node);
1257   init_req( InitialTest        , initial_test);
1258   init_req( ALength            , topnode);
1259   C->add_macro_node(this);
1260 }
1261 
1262 //=============================================================================
1263 Node* AllocateArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1264   if (remove_dead_region(phase, can_reshape))  return this;
1265   // Don't bother trying to transform a dead node
1266   if (in(0) && in(0)->is_top())  return NULL;
1267 
1268   const Type* type = phase->type(Ideal_length());
1269   if (type->isa_int() && type->is_int()->_hi < 0) {
1270     if (can_reshape) {
1271       PhaseIterGVN *igvn = phase->is_IterGVN();
1272       // Unreachable fall through path (negative array length),
1273       // the allocation can only throw so disconnect it.
1274       Node* proj = proj_out(TypeFunc::Control);
1275       Node* catchproj = NULL;
1276       if (proj != NULL) {
1277         for (DUIterator_Fast imax, i = proj->fast_outs(imax); i < imax; i++) {
1278           Node *cn = proj->fast_out(i);
1279           if (cn->is_Catch()) {
1280             catchproj = cn->as_Multi()->proj_out(CatchProjNode::fall_through_index);
1281             break;
1282           }
1283         }
1284       }
1285       if (catchproj != NULL && catchproj->outcnt() > 0 &&
1286           (catchproj->outcnt() > 1 ||
1287            catchproj->unique_out()->Opcode() != Op_Halt)) {
1288         assert(catchproj->is_CatchProj(), "must be a CatchProjNode");
1289         Node* nproj = catchproj->clone();
1290         igvn->register_new_node_with_optimizer(nproj);
1291 
1292         Node *frame = new ParmNode( phase->C->start(), TypeFunc::FramePtr );
1293         frame = phase->transform(frame);
1294         // Halt & Catch Fire
1295         Node *halt = new HaltNode( nproj, frame );
1296         phase->C->root()->add_req(halt);
1297         phase->transform(halt);
1298 
1299         igvn->replace_node(catchproj, phase->C->top());
1300         return this;
1301       }
1302     } else {
1303       // Can't correct it during regular GVN so register for IGVN
1304       phase->C->record_for_igvn(this);
1305     }
1306   }
1307   return NULL;
1308 }
1309 
1310 // Retrieve the length from the AllocateArrayNode. Narrow the type with a
1311 // CastII, if appropriate.  If we are not allowed to create new nodes, and
1312 // a CastII is appropriate, return NULL.
1313 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseTransform *phase, bool allow_new_nodes) {
1314   Node *length = in(AllocateNode::ALength);
1315   assert(length != NULL, "length is not null");
1316 
1317   const TypeInt* length_type = phase->find_int_type(length);
1318   const TypeAryPtr* ary_type = oop_type->isa_aryptr();
1319 
1320   if (ary_type != NULL && length_type != NULL) {
1321     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);
1322     if (narrow_length_type != length_type) {
1323       // Assert one of:
1324       //   - the narrow_length is 0
1325       //   - the narrow_length is not wider than length
1326       assert(narrow_length_type == TypeInt::ZERO ||
1327              length_type->is_con() && narrow_length_type->is_con() &&
1328                 (narrow_length_type->_hi <= length_type->_lo) ||
1329              (narrow_length_type->_hi <= length_type->_hi &&
1330               narrow_length_type->_lo >= length_type->_lo),
1331              "narrow type must be narrower than length type");
1332 
1333       // Return NULL if new nodes are not allowed
1334       if (!allow_new_nodes) return NULL;
1335       // Create a cast which is control dependent on the initialization to
1336       // propagate the fact that the array length must be positive.
1337       length = new CastIINode(length, narrow_length_type);
1338       length->set_req(0, initialization()->proj_out(0));
1339     }
1340   }
1341 
1342   return length;
1343 }
1344 
1345 //=============================================================================
1346 uint LockNode::size_of() const { return sizeof(*this); }
1347 
1348 // Redundant lock elimination
1349 //
1350 // There are various patterns of locking where we release and
1351 // immediately reacquire a lock in a piece of code where no operations
1352 // occur in between that would be observable.  In those cases we can
1353 // skip releasing and reacquiring the lock without violating any
1354 // fairness requirements.  Doing this around a loop could cause a lock
1355 // to be held for a very long time so we concentrate on non-looping
1356 // control flow.  We also require that the operations are fully
1357 // redundant meaning that we don't introduce new lock operations on
1358 // some paths so to be able to eliminate it on others ala PRE.  This
1359 // would probably require some more extensive graph manipulation to
1360 // guarantee that the memory edges were all handled correctly.
1361 //
1362 // Assuming p is a simple predicate which can't trap in any way and s
1363 // is a synchronized method consider this code:
1364 //
1365 //   s();
1366 //   if (p)
1367 //     s();
1368 //   else
1369 //     s();
1370 //   s();
1371 //
1372 // 1. The unlocks of the first call to s can be eliminated if the
1373 // locks inside the then and else branches are eliminated.
1374 //
1375 // 2. The unlocks of the then and else branches can be eliminated if
1376 // the lock of the final call to s is eliminated.
1377 //
1378 // Either of these cases subsumes the simple case of sequential control flow
1379 //
1380 // Addtionally we can eliminate versions without the else case:
1381 //
1382 //   s();
1383 //   if (p)
1384 //     s();
1385 //   s();
1386 //
1387 // 3. In this case we eliminate the unlock of the first s, the lock
1388 // and unlock in the then case and the lock in the final s.
1389 //
1390 // Note also that in all these cases the then/else pieces don't have
1391 // to be trivial as long as they begin and end with synchronization
1392 // operations.
1393 //
1394 //   s();
1395 //   if (p)
1396 //     s();
1397 //     f();
1398 //     s();
1399 //   s();
1400 //
1401 // The code will work properly for this case, leaving in the unlock
1402 // before the call to f and the relock after it.
1403 //
1404 // A potentially interesting case which isn't handled here is when the
1405 // locking is partially redundant.
1406 //
1407 //   s();
1408 //   if (p)
1409 //     s();
1410 //
1411 // This could be eliminated putting unlocking on the else case and
1412 // eliminating the first unlock and the lock in the then side.
1413 // Alternatively the unlock could be moved out of the then side so it
1414 // was after the merge and the first unlock and second lock
1415 // eliminated.  This might require less manipulation of the memory
1416 // state to get correct.
1417 //
1418 // Additionally we might allow work between a unlock and lock before
1419 // giving up eliminating the locks.  The current code disallows any
1420 // conditional control flow between these operations.  A formulation
1421 // similar to partial redundancy elimination computing the
1422 // availability of unlocking and the anticipatability of locking at a
1423 // program point would allow detection of fully redundant locking with
1424 // some amount of work in between.  I'm not sure how often I really
1425 // think that would occur though.  Most of the cases I've seen
1426 // indicate it's likely non-trivial work would occur in between.
1427 // There may be other more complicated constructs where we could
1428 // eliminate locking but I haven't seen any others appear as hot or
1429 // interesting.
1430 //
1431 // Locking and unlocking have a canonical form in ideal that looks
1432 // roughly like this:
1433 //
1434 //              <obj>
1435 //                | \\------+
1436 //                |  \       \
1437 //                | BoxLock   \
1438 //                |  |   |     \
1439 //                |  |    \     \
1440 //                |  |   FastLock
1441 //                |  |   /
1442 //                |  |  /
1443 //                |  |  |
1444 //
1445 //               Lock
1446 //                |
1447 //            Proj #0
1448 //                |
1449 //            MembarAcquire
1450 //                |
1451 //            Proj #0
1452 //
1453 //            MembarRelease
1454 //                |
1455 //            Proj #0
1456 //                |
1457 //              Unlock
1458 //                |
1459 //            Proj #0
1460 //
1461 //
1462 // This code proceeds by processing Lock nodes during PhaseIterGVN
1463 // and searching back through its control for the proper code
1464 // patterns.  Once it finds a set of lock and unlock operations to
1465 // eliminate they are marked as eliminatable which causes the
1466 // expansion of the Lock and Unlock macro nodes to make the operation a NOP
1467 //
1468 //=============================================================================
1469 
1470 //
1471 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:
1472 //   - copy regions.  (These may not have been optimized away yet.)
1473 //   - eliminated locking nodes
1474 //
1475 static Node *next_control(Node *ctrl) {
1476   if (ctrl == NULL)
1477     return NULL;
1478   while (1) {
1479     if (ctrl->is_Region()) {
1480       RegionNode *r = ctrl->as_Region();
1481       Node *n = r->is_copy();
1482       if (n == NULL)
1483         break;  // hit a region, return it
1484       else
1485         ctrl = n;
1486     } else if (ctrl->is_Proj()) {
1487       Node *in0 = ctrl->in(0);
1488       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {
1489         ctrl = in0->in(0);
1490       } else {
1491         break;
1492       }
1493     } else {
1494       break; // found an interesting control
1495     }
1496   }
1497   return ctrl;
1498 }
1499 //
1500 // Given a control, see if it's the control projection of an Unlock which
1501 // operating on the same object as lock.
1502 //
1503 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,
1504                                             GrowableArray<AbstractLockNode*> &lock_ops) {
1505   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : NULL;
1506   if (ctrl_proj != NULL && ctrl_proj->_con == TypeFunc::Control) {
1507     Node *n = ctrl_proj->in(0);
1508     if (n != NULL && n->is_Unlock()) {
1509       UnlockNode *unlock = n->as_Unlock();
1510       if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1511           BoxLockNode::same_slot(lock->box_node(), unlock->box_node()) &&
1512           !unlock->is_eliminated()) {
1513         lock_ops.append(unlock);
1514         return true;
1515       }
1516     }
1517   }
1518   return false;
1519 }
1520 
1521 //
1522 // Find the lock matching an unlock.  Returns null if a safepoint
1523 // or complicated control is encountered first.
1524 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {
1525   LockNode *lock_result = NULL;
1526   // find the matching lock, or an intervening safepoint
1527   Node *ctrl = next_control(unlock->in(0));
1528   while (1) {
1529     assert(ctrl != NULL, "invalid control graph");
1530     assert(!ctrl->is_Start(), "missing lock for unlock");
1531     if (ctrl->is_top()) break;  // dead control path
1532     if (ctrl->is_Proj()) ctrl = ctrl->in(0);
1533     if (ctrl->is_SafePoint()) {
1534         break;  // found a safepoint (may be the lock we are searching for)
1535     } else if (ctrl->is_Region()) {
1536       // Check for a simple diamond pattern.  Punt on anything more complicated
1537       if (ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(2) != NULL) {
1538         Node *in1 = next_control(ctrl->in(1));
1539         Node *in2 = next_control(ctrl->in(2));
1540         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||
1541              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {
1542           ctrl = next_control(in1->in(0)->in(0));
1543         } else {
1544           break;
1545         }
1546       } else {
1547         break;
1548       }
1549     } else {
1550       ctrl = next_control(ctrl->in(0));  // keep searching
1551     }
1552   }
1553   if (ctrl->is_Lock()) {
1554     LockNode *lock = ctrl->as_Lock();
1555     if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&
1556         BoxLockNode::same_slot(lock->box_node(), unlock->box_node())) {
1557       lock_result = lock;
1558     }
1559   }
1560   return lock_result;
1561 }
1562 
1563 // This code corresponds to case 3 above.
1564 
1565 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,
1566                                                        GrowableArray<AbstractLockNode*> &lock_ops) {
1567   Node* if_node = node->in(0);
1568   bool  if_true = node->is_IfTrue();
1569 
1570   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {
1571     Node *lock_ctrl = next_control(if_node->in(0));
1572     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {
1573       Node* lock1_node = NULL;
1574       ProjNode* proj = if_node->as_If()->proj_out(!if_true);
1575       if (if_true) {
1576         if (proj->is_IfFalse() && proj->outcnt() == 1) {
1577           lock1_node = proj->unique_out();
1578         }
1579       } else {
1580         if (proj->is_IfTrue() && proj->outcnt() == 1) {
1581           lock1_node = proj->unique_out();
1582         }
1583       }
1584       if (lock1_node != NULL && lock1_node->is_Lock()) {
1585         LockNode *lock1 = lock1_node->as_Lock();
1586         if (lock->obj_node()->eqv_uncast(lock1->obj_node()) &&
1587             BoxLockNode::same_slot(lock->box_node(), lock1->box_node()) &&
1588             !lock1->is_eliminated()) {
1589           lock_ops.append(lock1);
1590           return true;
1591         }
1592       }
1593     }
1594   }
1595 
1596   lock_ops.trunc_to(0);
1597   return false;
1598 }
1599 
1600 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,
1601                                GrowableArray<AbstractLockNode*> &lock_ops) {
1602   // check each control merging at this point for a matching unlock.
1603   // in(0) should be self edge so skip it.
1604   for (int i = 1; i < (int)region->req(); i++) {
1605     Node *in_node = next_control(region->in(i));
1606     if (in_node != NULL) {
1607       if (find_matching_unlock(in_node, lock, lock_ops)) {
1608         // found a match so keep on checking.
1609         continue;
1610       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {
1611         continue;
1612       }
1613 
1614       // If we fall through to here then it was some kind of node we
1615       // don't understand or there wasn't a matching unlock, so give
1616       // up trying to merge locks.
1617       lock_ops.trunc_to(0);
1618       return false;
1619     }
1620   }
1621   return true;
1622 
1623 }
1624 
1625 #ifndef PRODUCT
1626 //
1627 // Create a counter which counts the number of times this lock is acquired
1628 //
1629 void AbstractLockNode::create_lock_counter(JVMState* state) {
1630   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);
1631 }
1632 
1633 void AbstractLockNode::set_eliminated_lock_counter() {
1634   if (_counter) {
1635     // Update the counter to indicate that this lock was eliminated.
1636     // The counter update code will stay around even though the
1637     // optimizer will eliminate the lock operation itself.
1638     _counter->set_tag(NamedCounter::EliminatedLockCounter);
1639   }
1640 }
1641 #endif
1642 
1643 //=============================================================================
1644 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1645 
1646   // perform any generic optimizations first (returns 'this' or NULL)
1647   Node *result = SafePointNode::Ideal(phase, can_reshape);
1648   if (result != NULL)  return result;
1649   // Don't bother trying to transform a dead node
1650   if (in(0) && in(0)->is_top())  return NULL;
1651 
1652   // Now see if we can optimize away this lock.  We don't actually
1653   // remove the locking here, we simply set the _eliminate flag which
1654   // prevents macro expansion from expanding the lock.  Since we don't
1655   // modify the graph, the value returned from this function is the
1656   // one computed above.
1657   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1658     //
1659     // If we are locking an unescaped object, the lock/unlock is unnecessary
1660     //
1661     ConnectionGraph *cgr = phase->C->congraph();
1662     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1663       assert(!is_eliminated() || is_coarsened(), "sanity");
1664       // The lock could be marked eliminated by lock coarsening
1665       // code during first IGVN before EA. Replace coarsened flag
1666       // to eliminate all associated locks/unlocks.
1667       this->set_non_esc_obj();
1668       return result;
1669     }
1670 
1671     //
1672     // Try lock coarsening
1673     //
1674     PhaseIterGVN* iter = phase->is_IterGVN();
1675     if (iter != NULL && !is_eliminated()) {
1676 
1677       GrowableArray<AbstractLockNode*>   lock_ops;
1678 
1679       Node *ctrl = next_control(in(0));
1680 
1681       // now search back for a matching Unlock
1682       if (find_matching_unlock(ctrl, this, lock_ops)) {
1683         // found an unlock directly preceding this lock.  This is the
1684         // case of single unlock directly control dependent on a
1685         // single lock which is the trivial version of case 1 or 2.
1686       } else if (ctrl->is_Region() ) {
1687         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {
1688         // found lock preceded by multiple unlocks along all paths
1689         // joining at this point which is case 3 in description above.
1690         }
1691       } else {
1692         // see if this lock comes from either half of an if and the
1693         // predecessors merges unlocks and the other half of the if
1694         // performs a lock.
1695         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {
1696           // found unlock splitting to an if with locks on both branches.
1697         }
1698       }
1699 
1700       if (lock_ops.length() > 0) {
1701         // add ourselves to the list of locks to be eliminated.
1702         lock_ops.append(this);
1703 
1704   #ifndef PRODUCT
1705         if (PrintEliminateLocks) {
1706           int locks = 0;
1707           int unlocks = 0;
1708           for (int i = 0; i < lock_ops.length(); i++) {
1709             AbstractLockNode* lock = lock_ops.at(i);
1710             if (lock->Opcode() == Op_Lock)
1711               locks++;
1712             else
1713               unlocks++;
1714             if (Verbose) {
1715               lock->dump(1);
1716             }
1717           }
1718           tty->print_cr("***Eliminated %d unlocks and %d locks", unlocks, locks);
1719         }
1720   #endif
1721 
1722         // for each of the identified locks, mark them
1723         // as eliminatable
1724         for (int i = 0; i < lock_ops.length(); i++) {
1725           AbstractLockNode* lock = lock_ops.at(i);
1726 
1727           // Mark it eliminated by coarsening and update any counters
1728           lock->set_coarsened();
1729         }
1730       } else if (ctrl->is_Region() &&
1731                  iter->_worklist.member(ctrl)) {
1732         // We weren't able to find any opportunities but the region this
1733         // lock is control dependent on hasn't been processed yet so put
1734         // this lock back on the worklist so we can check again once any
1735         // region simplification has occurred.
1736         iter->_worklist.push(this);
1737       }
1738     }
1739   }
1740 
1741   return result;
1742 }
1743 
1744 //=============================================================================
1745 bool LockNode::is_nested_lock_region() {
1746   BoxLockNode* box = box_node()->as_BoxLock();
1747   int stk_slot = box->stack_slot();
1748   if (stk_slot <= 0)
1749     return false; // External lock or it is not Box (Phi node).
1750 
1751   // Ignore complex cases: merged locks or multiple locks.
1752   Node* obj = obj_node();
1753   LockNode* unique_lock = NULL;
1754   if (!box->is_simple_lock_region(&unique_lock, obj) ||
1755       (unique_lock != this)) {
1756     return false;
1757   }
1758 
1759   // Look for external lock for the same object.
1760   SafePointNode* sfn = this->as_SafePoint();
1761   JVMState* youngest_jvms = sfn->jvms();
1762   int max_depth = youngest_jvms->depth();
1763   for (int depth = 1; depth <= max_depth; depth++) {
1764     JVMState* jvms = youngest_jvms->of_depth(depth);
1765     int num_mon  = jvms->nof_monitors();
1766     // Loop over monitors
1767     for (int idx = 0; idx < num_mon; idx++) {
1768       Node* obj_node = sfn->monitor_obj(jvms, idx);
1769       BoxLockNode* box_node = sfn->monitor_box(jvms, idx)->as_BoxLock();
1770       if ((box_node->stack_slot() < stk_slot) && obj_node->eqv_uncast(obj)) {
1771         return true;
1772       }
1773     }
1774   }
1775   return false;
1776 }
1777 
1778 //=============================================================================
1779 uint UnlockNode::size_of() const { return sizeof(*this); }
1780 
1781 //=============================================================================
1782 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1783 
1784   // perform any generic optimizations first (returns 'this' or NULL)
1785   Node *result = SafePointNode::Ideal(phase, can_reshape);
1786   if (result != NULL)  return result;
1787   // Don't bother trying to transform a dead node
1788   if (in(0) && in(0)->is_top())  return NULL;
1789 
1790   // Now see if we can optimize away this unlock.  We don't actually
1791   // remove the unlocking here, we simply set the _eliminate flag which
1792   // prevents macro expansion from expanding the unlock.  Since we don't
1793   // modify the graph, the value returned from this function is the
1794   // one computed above.
1795   // Escape state is defined after Parse phase.
1796   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {
1797     //
1798     // If we are unlocking an unescaped object, the lock/unlock is unnecessary.
1799     //
1800     ConnectionGraph *cgr = phase->C->congraph();
1801     if (cgr != NULL && cgr->not_global_escape(obj_node())) {
1802       assert(!is_eliminated() || is_coarsened(), "sanity");
1803       // The lock could be marked eliminated by lock coarsening
1804       // code during first IGVN before EA. Replace coarsened flag
1805       // to eliminate all associated locks/unlocks.
1806       this->set_non_esc_obj();
1807     }
1808   }
1809   return result;
1810 }