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