Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "ci/bcEscapeAnalyzer.hpp"

 #include "compiler/oopMap.hpp"

 #include "opto/callGenerator.hpp"

 #include "opto/callnode.hpp"

 #include "opto/escape.hpp"

 #include "opto/locknode.hpp"

 #include "opto/machnode.hpp"

 #include "opto/matcher.hpp"

 #include "opto/parse.hpp"

 #include "opto/regalloc.hpp"

 #include "opto/regmask.hpp"

 #include "opto/rootnode.hpp"

 #include "opto/runtime.hpp"

 // Portions of code courtesy of Clifford Click

 // Optimization - Graph Style

 //=============================================================================

 uint StartNode::size_of() const { return sizeof(*this); }

 uint StartNode::cmp( const Node &n ) const

 { return _domain == ((StartNode&)n)._domain; }

 const Type *StartNode::bottom_type() const { return _domain; }

 const Type *StartNode::Value(PhaseTransform *phase) const { return _domain; }

 #ifndef PRODUCT

 void StartNode::dump_spec(outputStream *st) const { st->print(" #"); _domain->dump_on(st);}

 #endif

 //------------------------------Ideal------------------------------------------

 Node *StartNode::Ideal(PhaseGVN *phase, bool can_reshape){

   return remove_dead_region(phase, can_reshape) ? this : NULL;

 }

 //------------------------------calling_convention-----------------------------

 void StartNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {

   Matcher::calling_convention( sig_bt, parm_regs, argcnt, false );

 }

 //------------------------------Registers--------------------------------------

 const RegMask &StartNode::in_RegMask(uint) const {

   return RegMask::Empty;

 }

 //------------------------------match------------------------------------------

 // Construct projections for incoming parameters, and their RegMask info

 Node *StartNode::match( const ProjNode *proj, const Matcher *match ) {

   switch (proj->_con) {

   case TypeFunc::Control:

   case TypeFunc::I_O:

   case TypeFunc::Memory:

     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);

   case TypeFunc::FramePtr:

     return new (match->C) MachProjNode(this,proj->_con,Matcher::c_frame_ptr_mask, Op_RegP);

   case TypeFunc::ReturnAdr:

     return new (match->C) MachProjNode(this,proj->_con,match->_return_addr_mask,Op_RegP);

   case TypeFunc::Parms:

   default: {

       uint parm_num = proj->_con - TypeFunc::Parms;

       const Type *t = _domain->field_at(proj->_con);

       if (t->base() == Type::Half)  // 2nd half of Longs and Doubles

         return new (match->C) ConNode(Type::TOP);

       uint ideal_reg = t->ideal_reg();

       RegMask &rm = match->_calling_convention_mask[parm_num];

       return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);

     }

   }

   return NULL;

 }

 //------------------------------StartOSRNode----------------------------------

 // The method start node for an on stack replacement adapter

 //------------------------------osr_domain-----------------------------

 const TypeTuple *StartOSRNode::osr_domain() {

   const Type **fields = TypeTuple::fields(2);

   fields[TypeFunc::Parms+0] = TypeRawPtr::BOTTOM;  // address of osr buffer

   return TypeTuple::make(TypeFunc::Parms+1, fields);

 }

 //=============================================================================

 const char * const ParmNode::names[TypeFunc::Parms+1] = {

   "Control", "I_O", "Memory", "FramePtr", "ReturnAdr", "Parms"

 };

 #ifndef PRODUCT

 void ParmNode::dump_spec(outputStream *st) const {

   if( _con < TypeFunc::Parms ) {

     st->print(names[_con]);

   } else {

     st->print("Parm%d: ",_con-TypeFunc::Parms);

     // Verbose and WizardMode dump bottom_type for all nodes

     if( !Verbose && !WizardMode )   bottom_type()->dump_on(st);

   }

 }

 #endif

 uint ParmNode::ideal_reg() const {

   switch( _con ) {

   case TypeFunc::Control  : // fall through

   case TypeFunc::I_O      : // fall through

   case TypeFunc::Memory   : return 0;

   case TypeFunc::FramePtr : // fall through

   case TypeFunc::ReturnAdr: return Op_RegP;

   default                 : assert( _con > TypeFunc::Parms, "" );

     // fall through

   case TypeFunc::Parms    : {

     // Type of argument being passed

     const Type *t = in(0)->as_Start()->_domain->field_at(_con);

     return t->ideal_reg();

   }

   }

   ShouldNotReachHere();

   return 0;

 }

 //=============================================================================

 ReturnNode::ReturnNode(uint edges, Node *cntrl, Node *i_o, Node *memory, Node *frameptr, Node *retadr ) : Node(edges) {

   init_req(TypeFunc::Control,cntrl);

   init_req(TypeFunc::I_O,i_o);

   init_req(TypeFunc::Memory,memory);

   init_req(TypeFunc::FramePtr,frameptr);

   init_req(TypeFunc::ReturnAdr,retadr);

 }

 Node *ReturnNode::Ideal(PhaseGVN *phase, bool can_reshape){

   return remove_dead_region(phase, can_reshape) ? this : NULL;

 }

 const Type *ReturnNode::Value( PhaseTransform *phase ) const {

   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)

     ? Type::TOP

     : Type::BOTTOM;

 }

 // Do we Match on this edge index or not?  No edges on return nodes

 uint ReturnNode::match_edge(uint idx) const {

   return 0;

 }

 #ifndef PRODUCT

 void ReturnNode::dump_req() const {

   // Dump the required inputs, enclosed in '(' and ')'

   uint i;                       // Exit value of loop

   for( i=0; i<req(); i++ ) {    // For all required inputs

     if( i == TypeFunc::Parms ) tty->print("returns");

     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);

     else tty->print("_ ");

   }

 }

 #endif

 //=============================================================================

 RethrowNode::RethrowNode(

   Node* cntrl,

   Node* i_o,

   Node* memory,

   Node* frameptr,

   Node* ret_adr,

   Node* exception

 ) : Node(TypeFunc::Parms + 1) {

   init_req(TypeFunc::Control  , cntrl    );

   init_req(TypeFunc::I_O      , i_o      );

   init_req(TypeFunc::Memory   , memory   );

   init_req(TypeFunc::FramePtr , frameptr );

   init_req(TypeFunc::ReturnAdr, ret_adr);

   init_req(TypeFunc::Parms    , exception);

 }

 Node *RethrowNode::Ideal(PhaseGVN *phase, bool can_reshape){

   return remove_dead_region(phase, can_reshape) ? this : NULL;

 }

 const Type *RethrowNode::Value( PhaseTransform *phase ) const {

   return (phase->type(in(TypeFunc::Control)) == Type::TOP)

     ? Type::TOP

     : Type::BOTTOM;

 }

 uint RethrowNode::match_edge(uint idx) const {

   return 0;

 }

 #ifndef PRODUCT

 void RethrowNode::dump_req() const {

   // Dump the required inputs, enclosed in '(' and ')'

   uint i;                       // Exit value of loop

   for( i=0; i<req(); i++ ) {    // For all required inputs

     if( i == TypeFunc::Parms ) tty->print("exception");

     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);

     else tty->print("_ ");

   }

 }

 #endif

 //=============================================================================

 // Do we Match on this edge index or not?  Match only target address & method

 uint TailCallNode::match_edge(uint idx) const {

   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;

 }

 //=============================================================================

 // Do we Match on this edge index or not?  Match only target address & oop

 uint TailJumpNode::match_edge(uint idx) const {

   return TypeFunc::Parms <= idx  &&  idx <= TypeFunc::Parms+1;

 }

 //=============================================================================

 JVMState::JVMState(ciMethod* method, JVMState* caller) :

   _method(method) {

   assert(method != NULL, "must be valid call site");

   _reexecute = Reexecute_Undefined;

   debug_only(_bci = -99);  // random garbage value

   debug_only(_map = (SafePointNode*)-1);

   _caller = caller;

   _depth  = 1 + (caller == NULL ? 0 : caller->depth());

   _locoff = TypeFunc::Parms;

   _stkoff = _locoff + _method->max_locals();

   _monoff = _stkoff + _method->max_stack();

   _scloff = _monoff;

   _endoff = _monoff;

   _sp = 0;

 }

 JVMState::JVMState(int stack_size) :

   _method(NULL) {

   _bci = InvocationEntryBci;

   _reexecute = Reexecute_Undefined;

   debug_only(_map = (SafePointNode*)-1);

   _caller = NULL;

   _depth  = 1;

   _locoff = TypeFunc::Parms;

   _stkoff = _locoff;

   _monoff = _stkoff + stack_size;

   _scloff = _monoff;

   _endoff = _monoff;

   _sp = 0;

 }

 //--------------------------------of_depth-------------------------------------

 JVMState* JVMState::of_depth(int d) const {

   const JVMState* jvmp = this;

   assert(0 < d && (uint)d <= depth(), "oob");

   for (int skip = depth() - d; skip > 0; skip--) {

     jvmp = jvmp->caller();

   }

   assert(jvmp->depth() == (uint)d, "found the right one");

   return (JVMState*)jvmp;

 }

 //-----------------------------same_calls_as-----------------------------------

 bool JVMState::same_calls_as(const JVMState* that) const {

   if (this == that)                    return true;

   if (this->depth() != that->depth())  return false;

   const JVMState* p = this;

   const JVMState* q = that;

   for (;;) {

     if (p->_method != q->_method)    return false;

     if (p->_method == NULL)          return true;   // bci is irrelevant

     if (p->_bci    != q->_bci)       return false;

     if (p->_reexecute != q->_reexecute)  return false;

     p = p->caller();

     q = q->caller();

     if (p == q)                      return true;

     assert(p != NULL && q != NULL, "depth check ensures we don't run off end");

   }

 }

 //------------------------------debug_start------------------------------------

 uint JVMState::debug_start()  const {

   debug_only(JVMState* jvmroot = of_depth(1));

   assert(jvmroot->locoff() <= this->locoff(), "youngest JVMState must be last");

   return of_depth(1)->locoff();

 }

 //-------------------------------debug_end-------------------------------------

 uint JVMState::debug_end() const {

   debug_only(JVMState* jvmroot = of_depth(1));

   assert(jvmroot->endoff() <= this->endoff(), "youngest JVMState must be last");

   return endoff();

 }

 //------------------------------debug_depth------------------------------------

 uint JVMState::debug_depth() const {

   uint total = 0;

   for (const JVMState* jvmp = this; jvmp != NULL; jvmp = jvmp->caller()) {

     total += jvmp->debug_size();

   }

   return total;

 }

 #ifndef PRODUCT

 //------------------------------format_helper----------------------------------

 // Given an allocation (a Chaitin object) and a Node decide if the Node carries

 // any defined value or not.  If it does, print out the register or constant.

 static void format_helper( PhaseRegAlloc *regalloc, outputStream* st, Node *n, const char *msg, uint i, GrowableArray<SafePointScalarObjectNode*> *scobjs ) {

   if (n == NULL) { st->print(" NULL"); return; }

   if (n->is_SafePointScalarObject()) {

     // Scalar replacement.

     SafePointScalarObjectNode* spobj = n->as_SafePointScalarObject();

     scobjs->append_if_missing(spobj);

     int sco_n = scobjs->find(spobj);

     assert(sco_n >= 0, "");

     st->print(" %s%d]=#ScObj" INT32_FORMAT, msg, i, sco_n);

     return;

   }

   if( OptoReg::is_valid(regalloc->get_reg_first(n))) { // Check for undefined

     char buf[50];

     regalloc->dump_register(n,buf);

     st->print(" %s%d]=%s",msg,i,buf);

   } else {                      // No register, but might be constant

     const Type *t = n->bottom_type();

     switch (t->base()) {

     case Type::Int:

       st->print(" %s%d]=#"INT32_FORMAT,msg,i,t->is_int()->get_con());

       break;

     case Type::AnyPtr:

       assert( t == TypePtr::NULL_PTR, "" );

       st->print(" %s%d]=#NULL",msg,i);

       break;

     case Type::AryPtr:

     case Type::InstPtr:

       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->isa_oopptr()->const_oop());

       break;

     case Type::KlassPtr:

       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_klassptr()->klass());

       break;

     case Type::MetadataPtr:

       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_metadataptr()->metadata());

       break;

     case Type::NarrowOop:

       st->print(" %s%d]=#Ptr" INTPTR_FORMAT,msg,i,t->make_ptr()->isa_oopptr()->const_oop());

       break;

     case Type::RawPtr:

       st->print(" %s%d]=#Raw" INTPTR_FORMAT,msg,i,t->is_rawptr());

       break;

     case Type::DoubleCon:

       st->print(" %s%d]=#%fD",msg,i,t->is_double_constant()->_d);

       break;

     case Type::FloatCon:

       st->print(" %s%d]=#%fF",msg,i,t->is_float_constant()->_f);

       break;

     case Type::Long:

       st->print(" %s%d]=#"INT64_FORMAT,msg,i,t->is_long()->get_con());

       break;

     case Type::Half:

     case Type::Top:

       st->print(" %s%d]=_",msg,i);

       break;

     default: ShouldNotReachHere();

     }

   }

 }

 //------------------------------format-----------------------------------------

 void JVMState::format(PhaseRegAlloc *regalloc, const Node *n, outputStream* st) const {

   st->print("        #");

   if( _method ) {

     _method->print_short_name(st);

     st->print(" @ bci:%d ",_bci);

   } else {

     st->print_cr(" runtime stub ");

     return;

   }

   if (n->is_MachSafePoint()) {

     GrowableArray<SafePointScalarObjectNode*> scobjs;

     MachSafePointNode *mcall = n->as_MachSafePoint();

     uint i;

     // Print locals

     for( i = 0; i < (uint)loc_size(); i++ )

       format_helper( regalloc, st, mcall->local(this, i), "L[", i, &scobjs );

     // Print stack

     for (i = 0; i < (uint)stk_size(); i++) {

       if ((uint)(_stkoff + i) >= mcall->len())

         st->print(" oob ");

       else

        format_helper( regalloc, st, mcall->stack(this, i), "STK[", i, &scobjs );

     }

     for (i = 0; (int)i < nof_monitors(); i++) {

       Node *box = mcall->monitor_box(this, i);

       Node *obj = mcall->monitor_obj(this, i);

       if ( OptoReg::is_valid(regalloc->get_reg_first(box)) ) {

         box = BoxLockNode::box_node(box);

         format_helper( regalloc, st, box, "MON-BOX[", i, &scobjs );

       } else {

         OptoReg::Name box_reg = BoxLockNode::reg(box);

         st->print(" MON-BOX%d=%s+%d",

                    i,

                    OptoReg::regname(OptoReg::c_frame_pointer),

                    regalloc->reg2offset(box_reg));

       }

       const char* obj_msg = "MON-OBJ[";

       if (EliminateLocks) {

         if (BoxLockNode::box_node(box)->is_eliminated())

           obj_msg = "MON-OBJ(LOCK ELIMINATED)[";

       }

       format_helper( regalloc, st, obj, obj_msg, i, &scobjs );

     }

     for (i = 0; i < (uint)scobjs.length(); i++) {

       // Scalar replaced objects.

       st->print_cr("");

       st->print("        # ScObj" INT32_FORMAT " ", i);

       SafePointScalarObjectNode* spobj = scobjs.at(i);

       ciKlass* cik = spobj->bottom_type()->is_oopptr()->klass();

       assert(cik->is_instance_klass() ||

              cik->is_array_klass(), "Not supported allocation.");

       ciInstanceKlass *iklass = NULL;

       if (cik->is_instance_klass()) {

         cik->print_name_on(st);

         iklass = cik->as_instance_klass();

       } else if (cik->is_type_array_klass()) {

         cik->as_array_klass()->base_element_type()->print_name_on(st);

         st->print("[%d]", spobj->n_fields());

       } else if (cik->is_obj_array_klass()) {

         ciKlass* cie = cik->as_obj_array_klass()->base_element_klass();

         if (cie->is_instance_klass()) {

           cie->print_name_on(st);

         } else if (cie->is_type_array_klass()) {

           cie->as_array_klass()->base_element_type()->print_name_on(st);

         } else {

           ShouldNotReachHere();

         }

         st->print("[%d]", spobj->n_fields());

         int ndim = cik->as_array_klass()->dimension() - 1;

         while (ndim-- > 0) {

           st->print("[]");

         }

       }

       st->print("={");

       uint nf = spobj->n_fields();

       if (nf > 0) {

         uint first_ind = spobj->first_index();

         Node* fld_node = mcall->in(first_ind);

         ciField* cifield;

         if (iklass != NULL) {

           st->print(" [");

           cifield = iklass->nonstatic_field_at(0);

           cifield->print_name_on(st);

           format_helper( regalloc, st, fld_node, ":", 0, &scobjs );

         } else {

           format_helper( regalloc, st, fld_node, "[", 0, &scobjs );

         }

         for (uint j = 1; j < nf; j++) {

           fld_node = mcall->in(first_ind+j);

           if (iklass != NULL) {

             st->print(", [");

             cifield = iklass->nonstatic_field_at(j);

             cifield->print_name_on(st);

             format_helper( regalloc, st, fld_node, ":", j, &scobjs );

           } else {

             format_helper( regalloc, st, fld_node, ", [", j, &scobjs );

           }

         }

       }

       st->print(" }");

     }

   }

   st->print_cr("");

   if (caller() != NULL)  caller()->format(regalloc, n, st);

 }

 void JVMState::dump_spec(outputStream *st) const {

   if (_method != NULL) {

     bool printed = false;

     if (!Verbose) {

       // The JVMS dumps make really, really long lines.

       // Take out the most boring parts, which are the package prefixes.

       char buf[500];

       stringStream namest(buf, sizeof(buf));

       _method->print_short_name(&namest);

       if (namest.count() < sizeof(buf)) {

         const char* name = namest.base();

         if (name[0] == ' ')  ++name;

         const char* endcn = strchr(name, ':');  // end of class name

         if (endcn == NULL)  endcn = strchr(name, '(');

         if (endcn == NULL)  endcn = name + strlen(name);

         while (endcn > name && endcn[-1] != '.' && endcn[-1] != '/')

           --endcn;

         st->print(" %s", endcn);

         printed = true;

       }

     }

     if (!printed)

       _method->print_short_name(st);

     st->print(" @ bci:%d",_bci);

     if(_reexecute == Reexecute_True)

       st->print(" reexecute");

   } else {

     st->print(" runtime stub");

   }

   if (caller() != NULL)  caller()->dump_spec(st);

 }

 void JVMState::dump_on(outputStream* st) const {

   if (_map && !((uintptr_t)_map & 1)) {

     if (_map->len() > _map->req()) {  // _map->has_exceptions()

       Node* ex = _map->in(_map->req());  // _map->next_exception()

       // skip the first one; it's already being printed

       while (ex != NULL && ex->len() > ex->req()) {

         ex = ex->in(ex->req());  // ex->next_exception()

         ex->dump(1);

       }

     }

     _map->dump(2);

   }

   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=",

              depth(), locoff(), stkoff(), argoff(), monoff(), scloff(), endoff(), monitor_depth(), sp(), bci(), should_reexecute()?"true":"false");

   if (_method == NULL) {

     st->print_cr("(none)");

   } else {

     _method->print_name(st);

     st->cr();

     if (bci() >= 0 && bci() < _method->code_size()) {

       st->print("    bc: ");

       _method->print_codes_on(bci(), bci()+1, st);

     }

   }

   if (caller() != NULL) {

     caller()->dump_on(st);

   }

 }

 // Extra way to dump a jvms from the debugger,

 // to avoid a bug with C++ member function calls.

 void dump_jvms(JVMState* jvms) {

   jvms->dump();

 }

 #endif

 //--------------------------clone_shallow--------------------------------------

 JVMState* JVMState::clone_shallow(Compile* C) const {

   JVMState* n = has_method() ? new (C) JVMState(_method, _caller) : new (C) JVMState(0);

   n->set_bci(_bci);

   n->_reexecute = _reexecute;

   n->set_locoff(_locoff);

   n->set_stkoff(_stkoff);

   n->set_monoff(_monoff);

   n->set_scloff(_scloff);

   n->set_endoff(_endoff);

   n->set_sp(_sp);

   n->set_map(_map);

   return n;

 }

 //---------------------------clone_deep----------------------------------------

 JVMState* JVMState::clone_deep(Compile* C) const {

   JVMState* n = clone_shallow(C);

   for (JVMState* p = n; p->_caller != NULL; p = p->_caller) {

     p->_caller = p->_caller->clone_shallow(C);

   }

   assert(n->depth() == depth(), "sanity");

   assert(n->debug_depth() == debug_depth(), "sanity");

   return n;

 }

 //=============================================================================

 uint CallNode::cmp( const Node &n ) const

 { return _tf == ((CallNode&)n)._tf && _jvms == ((CallNode&)n)._jvms; }

 #ifndef PRODUCT

 void CallNode::dump_req() const {

   // Dump the required inputs, enclosed in '(' and ')'

   uint i;                       // Exit value of loop

   for( i=0; i<req(); i++ ) {    // For all required inputs

     if( i == TypeFunc::Parms ) tty->print("(");

     if( in(i) ) tty->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);

     else tty->print("_ ");

   }

   tty->print(")");

 }

 void CallNode::dump_spec(outputStream *st) const {

   st->print(" ");

   tf()->dump_on(st);

   if (_cnt != COUNT_UNKNOWN)  st->print(" C=%f",_cnt);

   if (jvms() != NULL)  jvms()->dump_spec(st);

 }

 #endif

 const Type *CallNode::bottom_type() const { return tf()->range(); }

 const Type *CallNode::Value(PhaseTransform *phase) const {

   if (phase->type(in(0)) == Type::TOP)  return Type::TOP;

   return tf()->range();

 }

 //------------------------------calling_convention-----------------------------

 void CallNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {

   // Use the standard compiler calling convention

   Matcher::calling_convention( sig_bt, parm_regs, argcnt, true );

 }

 //------------------------------match------------------------------------------

 // Construct projections for control, I/O, memory-fields, ..., and

 // return result(s) along with their RegMask info

 Node *CallNode::match( const ProjNode *proj, const Matcher *match ) {

   switch (proj->_con) {

   case TypeFunc::Control:

   case TypeFunc::I_O:

   case TypeFunc::Memory:

     return new (match->C) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);

   case TypeFunc::Parms+1:       // For LONG & DOUBLE returns

     assert(tf()->_range->field_at(TypeFunc::Parms+1) == Type::HALF, "");

     // 2nd half of doubles and longs

     return new (match->C) MachProjNode(this,proj->_con, RegMask::Empty, (uint)OptoReg::Bad);

   case TypeFunc::Parms: {       // Normal returns

     uint ideal_reg = tf()->range()->field_at(TypeFunc::Parms)->ideal_reg();

     OptoRegPair regs = is_CallRuntime()

       ? match->c_return_value(ideal_reg,true)  // Calls into C runtime

       : match->  return_value(ideal_reg,true); // Calls into compiled Java code

     RegMask rm = RegMask(regs.first());

     if( OptoReg::is_valid(regs.second()) )

       rm.Insert( regs.second() );

     return new (match->C) MachProjNode(this,proj->_con,rm,ideal_reg);

   }

   case TypeFunc::ReturnAdr:

   case TypeFunc::FramePtr:

   default:

     ShouldNotReachHere();

   }

   return NULL;

 }

 // Do we Match on this edge index or not?  Match no edges

 uint CallNode::match_edge(uint idx) const {

   return 0;

 }

 //

 // Determine whether the call could modify the field of the specified

 // instance at the specified offset.

 //

 bool CallNode::may_modify(const TypePtr *addr_t, PhaseTransform *phase) {

   const TypeOopPtr *adrInst_t  = addr_t->isa_oopptr();

   // If not an OopPtr or not an instance type, assume the worst.

   // Note: currently this method is called only for instance types.

   if (adrInst_t == NULL || !adrInst_t->is_known_instance()) {

     return true;

   }

   // The instance_id is set only for scalar-replaceable allocations which

   // are not passed as arguments according to Escape Analysis.

   return false;

 }

 // Does this call have a direct reference to n other than debug information?

 bool CallNode::has_non_debug_use(Node *n) {

   const TypeTuple * d = tf()->domain();

   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {

     Node *arg = in(i);

     if (arg == n) {

       return true;

     }

   }

   return false;

 }

 // Returns the unique CheckCastPP of a call

 // or 'this' if there are several CheckCastPP

 // or returns NULL if there is no one.

 Node *CallNode::result_cast() {

   Node *cast = NULL;

   Node *p = proj_out(TypeFunc::Parms);

   if (p == NULL)

     return NULL;

   for (DUIterator_Fast imax, i = p->fast_outs(imax); i < imax; i++) {

     Node *use = p->fast_out(i);

     if (use->is_CheckCastPP()) {

       if (cast != NULL) {

         return this;  // more than 1 CheckCastPP

       }

       cast = use;

     }

   }

   return cast;

 }

 void CallNode::extract_projections(CallProjections* projs, bool separate_io_proj) {

   projs->fallthrough_proj      = NULL;

   projs->fallthrough_catchproj = NULL;

   projs->fallthrough_ioproj    = NULL;

   projs->catchall_ioproj       = NULL;

   projs->catchall_catchproj    = NULL;

   projs->fallthrough_memproj   = NULL;

   projs->catchall_memproj      = NULL;

   projs->resproj               = NULL;

   projs->exobj                 = NULL;

   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {

     ProjNode *pn = fast_out(i)->as_Proj();

     if (pn->outcnt() == 0) continue;

     switch (pn->_con) {

     case TypeFunc::Control:

       {

         // For Control (fallthrough) and I_O (catch_all_index) we have CatchProj -> Catch -> Proj

         projs->fallthrough_proj = pn;

         DUIterator_Fast jmax, j = pn->fast_outs(jmax);

         const Node *cn = pn->fast_out(j);

         if (cn->is_Catch()) {

           ProjNode *cpn = NULL;

           for (DUIterator_Fast kmax, k = cn->fast_outs(kmax); k < kmax; k++) {

             cpn = cn->fast_out(k)->as_Proj();

             assert(cpn->is_CatchProj(), "must be a CatchProjNode");

             if (cpn->_con == CatchProjNode::fall_through_index)

               projs->fallthrough_catchproj = cpn;

             else {

               assert(cpn->_con == CatchProjNode::catch_all_index, "must be correct index.");

               projs->catchall_catchproj = cpn;

             }

           }

         }

         break;

       }

     case TypeFunc::I_O:

       if (pn->_is_io_use)

         projs->catchall_ioproj = pn;

       else

         projs->fallthrough_ioproj = pn;

       for (DUIterator j = pn->outs(); pn->has_out(j); j++) {

         Node* e = pn->out(j);

         if (e->Opcode() == Op_CreateEx && e->in(0)->is_CatchProj() && e->outcnt() > 0) {

           assert(projs->exobj == NULL, "only one");

           projs->exobj = e;

         }

       }

       break;

     case TypeFunc::Memory:

       if (pn->_is_io_use)

         projs->catchall_memproj = pn;

       else

         projs->fallthrough_memproj = pn;

       break;

     case TypeFunc::Parms:

       projs->resproj = pn;

       break;

     default:

       assert(false, "unexpected projection from allocation node.");

     }

   }

   // The resproj may not exist because the result couuld be ignored

   // and the exception object may not exist if an exception handler

   // swallows the exception but all the other must exist and be found.

   assert(projs->fallthrough_proj      != NULL, "must be found");

   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_catchproj != NULL, "must be found");

   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_memproj   != NULL, "must be found");

   assert(Compile::current()->inlining_incrementally() || projs->fallthrough_ioproj    != NULL, "must be found");

   assert(Compile::current()->inlining_incrementally() || projs->catchall_catchproj    != NULL, "must be found");

   if (separate_io_proj) {

     assert(Compile::current()->inlining_incrementally() || projs->catchall_memproj    != NULL, "must be found");

     assert(Compile::current()->inlining_incrementally() || projs->catchall_ioproj     != NULL, "must be found");

   }

 }

 Node *CallNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   CallGenerator* cg = generator();

   if (can_reshape && cg != NULL && cg->is_mh_late_inline() && !cg->already_attempted()) {

     // Check whether this MH handle call becomes a candidate for inlining

     ciMethod* callee = cg->method();

     vmIntrinsics::ID iid = callee->intrinsic_id();

     if (iid == vmIntrinsics::_invokeBasic) {

       if (in(TypeFunc::Parms)->Opcode() == Op_ConP) {

         phase->C->prepend_late_inline(cg);

         set_generator(NULL);

       }

     } else {

       assert(callee->has_member_arg(), "wrong type of call?");

       if (in(TypeFunc::Parms + callee->arg_size() - 1)->Opcode() == Op_ConP) {

         phase->C->prepend_late_inline(cg);

         set_generator(NULL);

       }

     }

   }

   return SafePointNode::Ideal(phase, can_reshape);

 }

 //=============================================================================

 uint CallJavaNode::size_of() const { return sizeof(*this); }

 uint CallJavaNode::cmp( const Node &n ) const {

   CallJavaNode &call = (CallJavaNode&)n;

   return CallNode::cmp(call) && _method == call._method;

 }

 #ifndef PRODUCT

 void CallJavaNode::dump_spec(outputStream *st) const {

   if( _method ) _method->print_short_name(st);

   CallNode::dump_spec(st);

 }

 #endif

 //=============================================================================

 uint CallStaticJavaNode::size_of() const { return sizeof(*this); }

 uint CallStaticJavaNode::cmp( const Node &n ) const {

   CallStaticJavaNode &call = (CallStaticJavaNode&)n;

   return CallJavaNode::cmp(call);

 }

 //----------------------------uncommon_trap_request----------------------------

 // If this is an uncommon trap, return the request code, else zero.

 int CallStaticJavaNode::uncommon_trap_request() const {

   if (_name != NULL && !strcmp(_name, "uncommon_trap")) {

     return extract_uncommon_trap_request(this);

   }

   return 0;

 }

 int CallStaticJavaNode::extract_uncommon_trap_request(const Node* call) {

 #ifndef PRODUCT

   if (!(call->req() > TypeFunc::Parms &&

         call->in(TypeFunc::Parms) != NULL &&

         call->in(TypeFunc::Parms)->is_Con())) {

     assert(_in_dump_cnt != 0, "OK if dumping");

     tty->print("[bad uncommon trap]");

     return 0;

   }

 #endif

   return call->in(TypeFunc::Parms)->bottom_type()->is_int()->get_con();

 }

 #ifndef PRODUCT

 void CallStaticJavaNode::dump_spec(outputStream *st) const {

   st->print("# Static ");

   if (_name != NULL) {

     st->print("%s", _name);

     int trap_req = uncommon_trap_request();

     if (trap_req != 0) {

       char buf[100];

       st->print("(%s)",

                  Deoptimization::format_trap_request(buf, sizeof(buf),

                                                      trap_req));

     }

     st->print(" ");

   }

   CallJavaNode::dump_spec(st);

 }

 #endif

 //=============================================================================

 uint CallDynamicJavaNode::size_of() const { return sizeof(*this); }

 uint CallDynamicJavaNode::cmp( const Node &n ) const {

   CallDynamicJavaNode &call = (CallDynamicJavaNode&)n;

   return CallJavaNode::cmp(call);

 }

 #ifndef PRODUCT

 void CallDynamicJavaNode::dump_spec(outputStream *st) const {

   st->print("# Dynamic ");

   CallJavaNode::dump_spec(st);

 }

 #endif

 //=============================================================================

 uint CallRuntimeNode::size_of() const { return sizeof(*this); }

 uint CallRuntimeNode::cmp( const Node &n ) const {

   CallRuntimeNode &call = (CallRuntimeNode&)n;

   return CallNode::cmp(call) && !strcmp(_name,call._name);

 }

 #ifndef PRODUCT

 void CallRuntimeNode::dump_spec(outputStream *st) const {

   st->print("# ");

   st->print(_name);

   CallNode::dump_spec(st);

 }

 #endif

 //------------------------------calling_convention-----------------------------

 void CallRuntimeNode::calling_convention( BasicType* sig_bt, VMRegPair *parm_regs, uint argcnt ) const {

   Matcher::c_calling_convention( sig_bt, parm_regs, argcnt );

 }

 //=============================================================================

 //------------------------------calling_convention-----------------------------

 //=============================================================================

 #ifndef PRODUCT

 void CallLeafNode::dump_spec(outputStream *st) const {

   st->print("# ");

   st->print(_name);

   CallNode::dump_spec(st);

 }

 #endif

 //=============================================================================

 void SafePointNode::set_local(JVMState* jvms, uint idx, Node *c) {

   assert(verify_jvms(jvms), "jvms must match");

   int loc = jvms->locoff() + idx;

   if (in(loc)->is_top() && idx > 0 && !c->is_top() ) {

     // If current local idx is top then local idx - 1 could

     // be a long/double that needs to be killed since top could

     // represent the 2nd half ofthe long/double.

     uint ideal = in(loc -1)->ideal_reg();

     if (ideal == Op_RegD || ideal == Op_RegL) {

       // set other (low index) half to top

       set_req(loc - 1, in(loc));

     }

   }

   set_req(loc, c);

 }

 uint SafePointNode::size_of() const { return sizeof(*this); }

 uint SafePointNode::cmp( const Node &n ) const {

   return (&n == this);          // Always fail except on self

 }

 //-------------------------set_next_exception----------------------------------

 void SafePointNode::set_next_exception(SafePointNode* n) {

   assert(n == NULL || n->Opcode() == Op_SafePoint, "correct value for next_exception");

   if (len() == req()) {

     if (n != NULL)  add_prec(n);

   } else {

     set_prec(req(), n);

   }

 }

 //----------------------------next_exception-----------------------------------

 SafePointNode* SafePointNode::next_exception() const {

   if (len() == req()) {

     return NULL;

   } else {

     Node* n = in(req());

     assert(n == NULL || n->Opcode() == Op_SafePoint, "no other uses of prec edges");

     return (SafePointNode*) n;

   }

 }

 //------------------------------Ideal------------------------------------------

 // Skip over any collapsed Regions

 Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   return remove_dead_region(phase, can_reshape) ? this : NULL;

 }

 //------------------------------Identity---------------------------------------

 // Remove obviously duplicate safepoints

 Node *SafePointNode::Identity( PhaseTransform *phase ) {

   // If you have back to back safepoints, remove one

   if( in(TypeFunc::Control)->is_SafePoint() )

     return in(TypeFunc::Control);

   if( in(0)->is_Proj() ) {

     Node *n0 = in(0)->in(0);

     // Check if he is a call projection (except Leaf Call)

     if( n0->is_Catch() ) {

       n0 = n0->in(0)->in(0);

       assert( n0->is_Call(), "expect a call here" );

     }

     if( n0->is_Call() && n0->as_Call()->guaranteed_safepoint() ) {

       // Useless Safepoint, so remove it

       return in(TypeFunc::Control);

     }

   }

   return this;

 }

 //------------------------------Value------------------------------------------

 const Type *SafePointNode::Value( PhaseTransform *phase ) const {

   if( phase->type(in(0)) == Type::TOP ) return Type::TOP;

   if( phase->eqv( in(0), this ) ) return Type::TOP; // Dead infinite loop

   return Type::CONTROL;

 }

 #ifndef PRODUCT

 void SafePointNode::dump_spec(outputStream *st) const {

   st->print(" SafePoint ");

 }

 #endif

 const RegMask &SafePointNode::in_RegMask(uint idx) const {

   if( idx < TypeFunc::Parms ) return RegMask::Empty;

   // Values outside the domain represent debug info

   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);

 }

 const RegMask &SafePointNode::out_RegMask() const {

   return RegMask::Empty;

 }

 void SafePointNode::grow_stack(JVMState* jvms, uint grow_by) {

   assert((int)grow_by > 0, "sanity");

   int monoff = jvms->monoff();

   int scloff = jvms->scloff();

   int endoff = jvms->endoff();

   assert(endoff == (int)req(), "no other states or debug info after me");

   Node* top = Compile::current()->top();

   for (uint i = 0; i < grow_by; i++) {

     ins_req(monoff, top);

   }

   jvms->set_monoff(monoff + grow_by);

   jvms->set_scloff(scloff + grow_by);

   jvms->set_endoff(endoff + grow_by);

 }

 void SafePointNode::push_monitor(const FastLockNode *lock) {

   // Add a LockNode, which points to both the original BoxLockNode (the

   // stack space for the monitor) and the Object being locked.

   const int MonitorEdges = 2;

   assert(JVMState::logMonitorEdges == exact_log2(MonitorEdges), "correct MonitorEdges");

   assert(req() == jvms()->endoff(), "correct sizing");

   int nextmon = jvms()->scloff();

   if (GenerateSynchronizationCode) {

     add_req(lock->box_node());

     add_req(lock->obj_node());

   } else {

     Node* top = Compile::current()->top();

     add_req(top);

     add_req(top);

   }

   jvms()->set_scloff(nextmon+MonitorEdges);

   jvms()->set_endoff(req());

 }

 void SafePointNode::pop_monitor() {

   // Delete last monitor from debug info

   debug_only(int num_before_pop = jvms()->nof_monitors());

   const int MonitorEdges = (1<<JVMState::logMonitorEdges);

   int scloff = jvms()->scloff();

   int endoff = jvms()->endoff();

   int new_scloff = scloff - MonitorEdges;

   int new_endoff = endoff - MonitorEdges;

   jvms()->set_scloff(new_scloff);

   jvms()->set_endoff(new_endoff);

   while (scloff > new_scloff)  del_req(--scloff);

   assert(jvms()->nof_monitors() == num_before_pop-1, "");

 }

 Node *SafePointNode::peek_monitor_box() const {

   int mon = jvms()->nof_monitors() - 1;

   assert(mon >= 0, "most have a monitor");

   return monitor_box(jvms(), mon);

 }

 Node *SafePointNode::peek_monitor_obj() const {

   int mon = jvms()->nof_monitors() - 1;

   assert(mon >= 0, "most have a monitor");

   return monitor_obj(jvms(), mon);

 }

 // Do we Match on this edge index or not?  Match no edges

 uint SafePointNode::match_edge(uint idx) const {

   if( !needs_polling_address_input() )

     return 0;

   return (TypeFunc::Parms == idx);

 }

 //==============  SafePointScalarObjectNode  ==============

 SafePointScalarObjectNode::SafePointScalarObjectNode(const TypeOopPtr* tp,

 #ifdef ASSERT

                                                      AllocateNode* alloc,

 #endif

                                                      uint first_index,

                                                      uint n_fields) :

   TypeNode(tp, 1), // 1 control input -- seems required.  Get from root.

 #ifdef ASSERT

   _alloc(alloc),

 #endif

   _first_index(first_index),

   _n_fields(n_fields)

 {

   init_class_id(Class_SafePointScalarObject);

 }

 // Do not allow value-numbering for SafePointScalarObject node.

 uint SafePointScalarObjectNode::hash() const { return NO_HASH; }

 uint SafePointScalarObjectNode::cmp( const Node &n ) const {

   return (&n == this); // Always fail except on self

 }

 uint SafePointScalarObjectNode::ideal_reg() const {

   return 0; // No matching to machine instruction

 }

 const RegMask &SafePointScalarObjectNode::in_RegMask(uint idx) const {

   return *(Compile::current()->matcher()->idealreg2debugmask[in(idx)->ideal_reg()]);

 }

 const RegMask &SafePointScalarObjectNode::out_RegMask() const {

   return RegMask::Empty;

 }

 uint SafePointScalarObjectNode::match_edge(uint idx) const {

   return 0;

 }

 SafePointScalarObjectNode*

 SafePointScalarObjectNode::clone(int jvms_adj, Dict* sosn_map) const {

   void* cached = (*sosn_map)[(void*)this];

   if (cached != NULL) {

     return (SafePointScalarObjectNode*)cached;

   }

   SafePointScalarObjectNode* res = (SafePointScalarObjectNode*)Node::clone();

   res->_first_index += jvms_adj;

   sosn_map->Insert((void*)this, (void*)res);

   return res;

 }

 #ifndef PRODUCT

 void SafePointScalarObjectNode::dump_spec(outputStream *st) const {

   st->print(" # fields@[%d..%d]", first_index(),

              first_index() + n_fields() - 1);

 }

 #endif

 //=============================================================================

 uint AllocateNode::size_of() const { return sizeof(*this); }

 AllocateNode::AllocateNode(Compile* C, const TypeFunc *atype,

                            Node *ctrl, Node *mem, Node *abio,

                            Node *size, Node *klass_node, Node *initial_test)

   : CallNode(atype, NULL, TypeRawPtr::BOTTOM)

 {

   init_class_id(Class_Allocate);

   init_flags(Flag_is_macro);

   _is_scalar_replaceable = false;

   Node *topnode = C->top();

   init_req( TypeFunc::Control  , ctrl );

   init_req( TypeFunc::I_O      , abio );

   init_req( TypeFunc::Memory   , mem );

   init_req( TypeFunc::ReturnAdr, topnode );

   init_req( TypeFunc::FramePtr , topnode );

   init_req( AllocSize          , size);

   init_req( KlassNode          , klass_node);

   init_req( InitialTest        , initial_test);

   init_req( ALength            , topnode);

   C->add_macro_node(this);

 }

 //=============================================================================

 uint AllocateArrayNode::size_of() const { return sizeof(*this); }

 Node* AllocateArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   if (remove_dead_region(phase, can_reshape))  return this;

   // Don't bother trying to transform a dead node

   if (in(0) && in(0)->is_top())  return NULL;

   const Type* type = phase->type(Ideal_length());

   if (type->isa_int() && type->is_int()->_hi < 0) {

     if (can_reshape) {

       PhaseIterGVN *igvn = phase->is_IterGVN();

       // Unreachable fall through path (negative array length),

       // the allocation can only throw so disconnect it.

       Node* proj = proj_out(TypeFunc::Control);

       Node* catchproj = NULL;

       if (proj != NULL) {

         for (DUIterator_Fast imax, i = proj->fast_outs(imax); i < imax; i++) {

           Node *cn = proj->fast_out(i);

           if (cn->is_Catch()) {

             catchproj = cn->as_Multi()->proj_out(CatchProjNode::fall_through_index);

             break;

           }

         }

       }

       if (catchproj != NULL && catchproj->outcnt() > 0 &&

           (catchproj->outcnt() > 1 ||

            catchproj->unique_out()->Opcode() != Op_Halt)) {

         assert(catchproj->is_CatchProj(), "must be a CatchProjNode");

         Node* nproj = catchproj->clone();

         igvn->register_new_node_with_optimizer(nproj);

         Node *frame = new (phase->C) ParmNode( phase->C->start(), TypeFunc::FramePtr );

         frame = phase->transform(frame);

         // Halt & Catch Fire

         Node *halt = new (phase->C) HaltNode( nproj, frame );

         phase->C->root()->add_req(halt);

         phase->transform(halt);

         igvn->replace_node(catchproj, phase->C->top());

         return this;

       }

     } else {

       // Can't correct it during regular GVN so register for IGVN

       phase->C->record_for_igvn(this);

     }

   }

   return NULL;

 }

 // Retrieve the length from the AllocateArrayNode. Narrow the type with a

 // CastII, if appropriate.  If we are not allowed to create new nodes, and

 // a CastII is appropriate, return NULL.

 Node *AllocateArrayNode::make_ideal_length(const TypeOopPtr* oop_type, PhaseTransform *phase, bool allow_new_nodes) {

   Node *length = in(AllocateNode::ALength);

   assert(length != NULL, "length is not null");

   const TypeInt* length_type = phase->find_int_type(length);

   const TypeAryPtr* ary_type = oop_type->isa_aryptr();

   if (ary_type != NULL && length_type != NULL) {

     const TypeInt* narrow_length_type = ary_type->narrow_size_type(length_type);

     if (narrow_length_type != length_type) {

       // Assert one of:

       //   - the narrow_length is 0

       //   - the narrow_length is not wider than length

       assert(narrow_length_type == TypeInt::ZERO ||

              (narrow_length_type->_hi <= length_type->_hi &&

               narrow_length_type->_lo >= length_type->_lo),

              "narrow type must be narrower than length type");

       // Return NULL if new nodes are not allowed

       if (!allow_new_nodes) return NULL;

       // Create a cast which is control dependent on the initialization to

       // propagate the fact that the array length must be positive.

       length = new (phase->C) CastIINode(length, narrow_length_type);

       length->set_req(0, initialization()->proj_out(0));

     }

   }

   return length;

 }

 //=============================================================================

 uint LockNode::size_of() const { return sizeof(*this); }

 // Redundant lock elimination

 //

 // There are various patterns of locking where we release and

 // immediately reacquire a lock in a piece of code where no operations

 // occur in between that would be observable.  In those cases we can

 // skip releasing and reacquiring the lock without violating any

 // fairness requirements.  Doing this around a loop could cause a lock

 // to be held for a very long time so we concentrate on non-looping

 // control flow.  We also require that the operations are fully

 // redundant meaning that we don't introduce new lock operations on

 // some paths so to be able to eliminate it on others ala PRE.  This

 // would probably require some more extensive graph manipulation to

 // guarantee that the memory edges were all handled correctly.

 //

 // Assuming p is a simple predicate which can't trap in any way and s

 // is a synchronized method consider this code:

 //

 //   s();

 //   if (p)

 //     s();

 //   else

 //     s();

 //   s();

 //

 // 1. The unlocks of the first call to s can be eliminated if the

 // locks inside the then and else branches are eliminated.

 //

 // 2. The unlocks of the then and else branches can be eliminated if

 // the lock of the final call to s is eliminated.

 //

 // Either of these cases subsumes the simple case of sequential control flow

 //

 // Addtionally we can eliminate versions without the else case:

 //

 //   s();

 //   if (p)

 //     s();

 //   s();

 //

 // 3. In this case we eliminate the unlock of the first s, the lock

 // and unlock in the then case and the lock in the final s.

 //

 // Note also that in all these cases the then/else pieces don't have

 // to be trivial as long as they begin and end with synchronization

 // operations.

 //

 //   s();

 //   if (p)

 //     s();

 //     f();

 //     s();

 //   s();

 //

 // The code will work properly for this case, leaving in the unlock

 // before the call to f and the relock after it.

 //

 // A potentially interesting case which isn't handled here is when the

 // locking is partially redundant.

 //

 //   s();

 //   if (p)

 //     s();

 //

 // This could be eliminated putting unlocking on the else case and

 // eliminating the first unlock and the lock in the then side.

 // Alternatively the unlock could be moved out of the then side so it

 // was after the merge and the first unlock and second lock

 // eliminated.  This might require less manipulation of the memory

 // state to get correct.

 //

 // Additionally we might allow work between a unlock and lock before

 // giving up eliminating the locks.  The current code disallows any

 // conditional control flow between these operations.  A formulation

 // similar to partial redundancy elimination computing the

 // availability of unlocking and the anticipatability of locking at a

 // program point would allow detection of fully redundant locking with

 // some amount of work in between.  I'm not sure how often I really

 // think that would occur though.  Most of the cases I've seen

 // indicate it's likely non-trivial work would occur in between.

 // There may be other more complicated constructs where we could

 // eliminate locking but I haven't seen any others appear as hot or

 // interesting.

 //

 // Locking and unlocking have a canonical form in ideal that looks

 // roughly like this:

 //

 //              <obj>

 //                | \\------+

 //                |  \       \

 //                | BoxLock   \

 //                |  |   |     \

 //                |  |    \     \

 //                |  |   FastLock

 //                |  |   /

 //                |  |  /

 //                |  |  |

 //

 //               Lock

 //                |

 //            Proj #0

 //                |

 //            MembarAcquire

 //                |

 //            Proj #0

 //

 //            MembarRelease

 //                |

 //            Proj #0

 //                |

 //              Unlock

 //                |

 //            Proj #0

 //

 //

 // This code proceeds by processing Lock nodes during PhaseIterGVN

 // and searching back through its control for the proper code

 // patterns.  Once it finds a set of lock and unlock operations to

 // eliminate they are marked as eliminatable which causes the

 // expansion of the Lock and Unlock macro nodes to make the operation a NOP

 //

 //=============================================================================

 //

 // Utility function to skip over uninteresting control nodes.  Nodes skipped are:

 //   - copy regions.  (These may not have been optimized away yet.)

 //   - eliminated locking nodes

 //

 static Node *next_control(Node *ctrl) {

   if (ctrl == NULL)

     return NULL;

   while (1) {

     if (ctrl->is_Region()) {

       RegionNode *r = ctrl->as_Region();

       Node *n = r->is_copy();

       if (n == NULL)

         break;  // hit a region, return it

       else

         ctrl = n;

     } else if (ctrl->is_Proj()) {

       Node *in0 = ctrl->in(0);

       if (in0->is_AbstractLock() && in0->as_AbstractLock()->is_eliminated()) {

         ctrl = in0->in(0);

       } else {

         break;

       }

     } else {

       break; // found an interesting control

     }

   }

   return ctrl;

 }

 //

 // Given a control, see if it's the control projection of an Unlock which

 // operating on the same object as lock.

 //

 bool AbstractLockNode::find_matching_unlock(const Node* ctrl, LockNode* lock,

                                             GrowableArray<AbstractLockNode*> &lock_ops) {

   ProjNode *ctrl_proj = (ctrl->is_Proj()) ? ctrl->as_Proj() : NULL;

   if (ctrl_proj != NULL && ctrl_proj->_con == TypeFunc::Control) {

     Node *n = ctrl_proj->in(0);

     if (n != NULL && n->is_Unlock()) {

       UnlockNode *unlock = n->as_Unlock();

       if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&

           BoxLockNode::same_slot(lock->box_node(), unlock->box_node()) &&

           !unlock->is_eliminated()) {

         lock_ops.append(unlock);

         return true;

       }

     }

   }

   return false;

 }

 //

 // Find the lock matching an unlock.  Returns null if a safepoint

 // or complicated control is encountered first.

 LockNode *AbstractLockNode::find_matching_lock(UnlockNode* unlock) {

   LockNode *lock_result = NULL;

   // find the matching lock, or an intervening safepoint

   Node *ctrl = next_control(unlock->in(0));

   while (1) {

     assert(ctrl != NULL, "invalid control graph");

     assert(!ctrl->is_Start(), "missing lock for unlock");

     if (ctrl->is_top()) break;  // dead control path

     if (ctrl->is_Proj()) ctrl = ctrl->in(0);

     if (ctrl->is_SafePoint()) {

         break;  // found a safepoint (may be the lock we are searching for)

     } else if (ctrl->is_Region()) {

       // Check for a simple diamond pattern.  Punt on anything more complicated

       if (ctrl->req() == 3 && ctrl->in(1) != NULL && ctrl->in(2) != NULL) {

         Node *in1 = next_control(ctrl->in(1));

         Node *in2 = next_control(ctrl->in(2));

         if (((in1->is_IfTrue() && in2->is_IfFalse()) ||

              (in2->is_IfTrue() && in1->is_IfFalse())) && (in1->in(0) == in2->in(0))) {

           ctrl = next_control(in1->in(0)->in(0));

         } else {

           break;

         }

       } else {

         break;

       }

     } else {

       ctrl = next_control(ctrl->in(0));  // keep searching

     }

   }

   if (ctrl->is_Lock()) {

     LockNode *lock = ctrl->as_Lock();

     if (lock->obj_node()->eqv_uncast(unlock->obj_node()) &&

         BoxLockNode::same_slot(lock->box_node(), unlock->box_node())) {

       lock_result = lock;

     }

   }

   return lock_result;

 }

 // This code corresponds to case 3 above.

 bool AbstractLockNode::find_lock_and_unlock_through_if(Node* node, LockNode* lock,

                                                        GrowableArray<AbstractLockNode*> &lock_ops) {

   Node* if_node = node->in(0);

   bool  if_true = node->is_IfTrue();

   if (if_node->is_If() && if_node->outcnt() == 2 && (if_true || node->is_IfFalse())) {

     Node *lock_ctrl = next_control(if_node->in(0));

     if (find_matching_unlock(lock_ctrl, lock, lock_ops)) {

       Node* lock1_node = NULL;

       ProjNode* proj = if_node->as_If()->proj_out(!if_true);

       if (if_true) {

         if (proj->is_IfFalse() && proj->outcnt() == 1) {

           lock1_node = proj->unique_out();

         }

       } else {

         if (proj->is_IfTrue() && proj->outcnt() == 1) {

           lock1_node = proj->unique_out();

         }

       }

       if (lock1_node != NULL && lock1_node->is_Lock()) {

         LockNode *lock1 = lock1_node->as_Lock();

         if (lock->obj_node()->eqv_uncast(lock1->obj_node()) &&

             BoxLockNode::same_slot(lock->box_node(), lock1->box_node()) &&

             !lock1->is_eliminated()) {

           lock_ops.append(lock1);

           return true;

         }

       }

     }

   }

   lock_ops.trunc_to(0);

   return false;

 }

 bool AbstractLockNode::find_unlocks_for_region(const RegionNode* region, LockNode* lock,

                                GrowableArray<AbstractLockNode*> &lock_ops) {

   // check each control merging at this point for a matching unlock.

   // in(0) should be self edge so skip it.

   for (int i = 1; i < (int)region->req(); i++) {

     Node *in_node = next_control(region->in(i));

     if (in_node != NULL) {

       if (find_matching_unlock(in_node, lock, lock_ops)) {

         // found a match so keep on checking.

         continue;

       } else if (find_lock_and_unlock_through_if(in_node, lock, lock_ops)) {

         continue;

       }

       // If we fall through to here then it was some kind of node we

       // don't understand or there wasn't a matching unlock, so give

       // up trying to merge locks.

       lock_ops.trunc_to(0);

       return false;

     }

   }

   return true;

 }

 #ifndef PRODUCT

 //

 // Create a counter which counts the number of times this lock is acquired

 //

 void AbstractLockNode::create_lock_counter(JVMState* state) {

   _counter = OptoRuntime::new_named_counter(state, NamedCounter::LockCounter);

 }

 void AbstractLockNode::set_eliminated_lock_counter() {

   if (_counter) {

     // Update the counter to indicate that this lock was eliminated.

     // The counter update code will stay around even though the

     // optimizer will eliminate the lock operation itself.

     _counter->set_tag(NamedCounter::EliminatedLockCounter);

   }

 }

 #endif

 //=============================================================================

 Node *LockNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   // perform any generic optimizations first (returns 'this' or NULL)

   Node *result = SafePointNode::Ideal(phase, can_reshape);

   if (result != NULL)  return result;

   // Don't bother trying to transform a dead node

   if (in(0) && in(0)->is_top())  return NULL;

   // Now see if we can optimize away this lock.  We don't actually

   // remove the locking here, we simply set the _eliminate flag which

   // prevents macro expansion from expanding the lock.  Since we don't

   // modify the graph, the value returned from this function is the

   // one computed above.

   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {

     //

     // If we are locking an unescaped object, the lock/unlock is unnecessary

     //

     ConnectionGraph *cgr = phase->C->congraph();

     if (cgr != NULL && cgr->not_global_escape(obj_node())) {

       assert(!is_eliminated() || is_coarsened(), "sanity");

       // The lock could be marked eliminated by lock coarsening

       // code during first IGVN before EA. Replace coarsened flag

       // to eliminate all associated locks/unlocks.

       this->set_non_esc_obj();

       return result;

     }

     //

     // Try lock coarsening

     //

     PhaseIterGVN* iter = phase->is_IterGVN();

     if (iter != NULL && !is_eliminated()) {

       GrowableArray<AbstractLockNode*>   lock_ops;

       Node *ctrl = next_control(in(0));

       // now search back for a matching Unlock

       if (find_matching_unlock(ctrl, this, lock_ops)) {

         // found an unlock directly preceding this lock.  This is the

         // case of single unlock directly control dependent on a

         // single lock which is the trivial version of case 1 or 2.

       } else if (ctrl->is_Region() ) {

         if (find_unlocks_for_region(ctrl->as_Region(), this, lock_ops)) {

         // found lock preceded by multiple unlocks along all paths

         // joining at this point which is case 3 in description above.

         }

       } else {

         // see if this lock comes from either half of an if and the

         // predecessors merges unlocks and the other half of the if

         // performs a lock.

         if (find_lock_and_unlock_through_if(ctrl, this, lock_ops)) {

           // found unlock splitting to an if with locks on both branches.

         }

       }

       if (lock_ops.length() > 0) {

         // add ourselves to the list of locks to be eliminated.

         lock_ops.append(this);

   #ifndef PRODUCT

         if (PrintEliminateLocks) {

           int locks = 0;

           int unlocks = 0;

           for (int i = 0; i < lock_ops.length(); i++) {

             AbstractLockNode* lock = lock_ops.at(i);

             if (lock->Opcode() == Op_Lock)

               locks++;

             else

               unlocks++;

             if (Verbose) {

               lock->dump(1);

             }

           }

           tty->print_cr("***Eliminated %d unlocks and %d locks", unlocks, locks);

         }

   #endif

         // for each of the identified locks, mark them

         // as eliminatable

         for (int i = 0; i < lock_ops.length(); i++) {

           AbstractLockNode* lock = lock_ops.at(i);

           // Mark it eliminated by coarsening and update any counters

           lock->set_coarsened();

         }

       } else if (ctrl->is_Region() &&

                  iter->_worklist.member(ctrl)) {

         // We weren't able to find any opportunities but the region this

         // lock is control dependent on hasn't been processed yet so put

         // this lock back on the worklist so we can check again once any

         // region simplification has occurred.

         iter->_worklist.push(this);

       }

     }

   }

   return result;

 }

 //=============================================================================

 bool LockNode::is_nested_lock_region() {

   BoxLockNode* box = box_node()->as_BoxLock();

   int stk_slot = box->stack_slot();

   if (stk_slot <= 0)

     return false; // External lock or it is not Box (Phi node).

   // Ignore complex cases: merged locks or multiple locks.

   Node* obj = obj_node();

   LockNode* unique_lock = NULL;

   if (!box->is_simple_lock_region(&unique_lock, obj) ||

       (unique_lock != this)) {

     return false;

   }

   // Look for external lock for the same object.

   SafePointNode* sfn = this->as_SafePoint();

   JVMState* youngest_jvms = sfn->jvms();

   int max_depth = youngest_jvms->depth();

   for (int depth = 1; depth <= max_depth; depth++) {

     JVMState* jvms = youngest_jvms->of_depth(depth);

     int num_mon  = jvms->nof_monitors();

     // Loop over monitors

     for (int idx = 0; idx < num_mon; idx++) {

       Node* obj_node = sfn->monitor_obj(jvms, idx);

       BoxLockNode* box_node = sfn->monitor_box(jvms, idx)->as_BoxLock();

       if ((box_node->stack_slot() < stk_slot) && obj_node->eqv_uncast(obj)) {

         return true;

       }

     }

   }

   return false;

 }

 //=============================================================================

 uint UnlockNode::size_of() const { return sizeof(*this); }

 //=============================================================================

 Node *UnlockNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   // perform any generic optimizations first (returns 'this' or NULL)

   Node *result = SafePointNode::Ideal(phase, can_reshape);

   if (result != NULL)  return result;

   // Don't bother trying to transform a dead node

   if (in(0) && in(0)->is_top())  return NULL;

   // Now see if we can optimize away this unlock.  We don't actually

   // remove the unlocking here, we simply set the _eliminate flag which

   // prevents macro expansion from expanding the unlock.  Since we don't

   // modify the graph, the value returned from this function is the

   // one computed above.

   // Escape state is defined after Parse phase.

   if (can_reshape && EliminateLocks && !is_non_esc_obj()) {

     //

     // If we are unlocking an unescaped object, the lock/unlock is unnecessary.

     //

     ConnectionGraph *cgr = phase->C->congraph();

     if (cgr != NULL && cgr->not_global_escape(obj_node())) {

       assert(!is_eliminated() || is_coarsened(), "sanity");

       // The lock could be marked eliminated by lock coarsening

       // code during first IGVN before EA. Replace coarsened flag

       // to eliminate all associated locks/unlocks.

       this->set_non_esc_obj();

     }

   }

   return result;

 }