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

 /*

  * Copyright (c) 2005, 2011, 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 "libadt/vectset.hpp"

 #include "memory/allocation.hpp"

 #include "opto/c2compiler.hpp"

 #include "opto/callnode.hpp"

 #include "opto/cfgnode.hpp"

 #include "opto/compile.hpp"

 #include "opto/escape.hpp"

 #include "opto/phaseX.hpp"

 #include "opto/rootnode.hpp"

 void PointsToNode::add_edge(uint targIdx, PointsToNode::EdgeType et) {

   uint v = (targIdx << EdgeShift) + ((uint) et);

   if (_edges == NULL) {

      Arena *a = Compile::current()->comp_arena();

     _edges = new(a) GrowableArray<uint>(a, INITIAL_EDGE_COUNT, 0, 0);

   }

   _edges->append_if_missing(v);

 }

 void PointsToNode::remove_edge(uint targIdx, PointsToNode::EdgeType et) {

   uint v = (targIdx << EdgeShift) + ((uint) et);

   _edges->remove(v);

 }

 #ifndef PRODUCT

 static const char *node_type_names[] = {

   "UnknownType",

   "JavaObject",

   "LocalVar",

   "Field"

 };

 static const char *esc_names[] = {

   "UnknownEscape",

   "NoEscape",

   "ArgEscape",

   "GlobalEscape"

 };

 static const char *edge_type_suffix[] = {

  "?", // UnknownEdge

  "P", // PointsToEdge

  "D", // DeferredEdge

  "F"  // FieldEdge

 };

 void PointsToNode::dump(bool print_state) const {

   NodeType nt = node_type();

   tty->print("%s ", node_type_names[(int) nt]);

   if (print_state) {

     EscapeState es = escape_state();

     tty->print("%s %s ", esc_names[(int) es], _scalar_replaceable ? "":"NSR");

   }

   tty->print("[[");

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

     tty->print(" %d%s", edge_target(i), edge_type_suffix[(int) edge_type(i)]);

   }

   tty->print("]]  ");

   if (_node == NULL)

     tty->print_cr("<null>");

   else

     _node->dump();

 }

 #endif

 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :

   _nodes(C->comp_arena(), C->unique(), C->unique(), PointsToNode()),

   _processed(C->comp_arena()),

   pt_ptset(C->comp_arena()),

   pt_visited(C->comp_arena()),

   pt_worklist(C->comp_arena(), 4, 0, 0),

   _collecting(true),

   _progress(false),

   _compile(C),

   _igvn(igvn),

   _node_map(C->comp_arena()) {

   _phantom_object = C->top()->_idx,

   add_node(C->top(), PointsToNode::JavaObject, PointsToNode::GlobalEscape,true);

   // Add ConP(#NULL) and ConN(#NULL) nodes.

   Node* oop_null = igvn->zerocon(T_OBJECT);

   _oop_null = oop_null->_idx;

   assert(_oop_null < nodes_size(), "should be created already");

   add_node(oop_null, PointsToNode::JavaObject, PointsToNode::NoEscape, true);

   if (UseCompressedOops) {

     Node* noop_null = igvn->zerocon(T_NARROWOOP);

     _noop_null = noop_null->_idx;

     assert(_noop_null < nodes_size(), "should be created already");

     add_node(noop_null, PointsToNode::JavaObject, PointsToNode::NoEscape, true);

   } else {

     _noop_null = _oop_null; // Should be initialized

   }

   _pcmp_neq = NULL; // Should be initialized

   _pcmp_eq  = NULL;

 }

 void ConnectionGraph::add_pointsto_edge(uint from_i, uint to_i) {

   PointsToNode *f = ptnode_adr(from_i);

   PointsToNode *t = ptnode_adr(to_i);

   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");

   assert(f->node_type() == PointsToNode::LocalVar || f->node_type() == PointsToNode::Field, "invalid source of PointsTo edge");

   assert(t->node_type() == PointsToNode::JavaObject, "invalid destination of PointsTo edge");

   add_edge(f, to_i, PointsToNode::PointsToEdge);

 }

 void ConnectionGraph::add_deferred_edge(uint from_i, uint to_i) {

   PointsToNode *f = ptnode_adr(from_i);

   PointsToNode *t = ptnode_adr(to_i);

   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");

   assert(f->node_type() == PointsToNode::LocalVar || f->node_type() == PointsToNode::Field, "invalid source of Deferred edge");

   assert(t->node_type() == PointsToNode::LocalVar || t->node_type() == PointsToNode::Field, "invalid destination of Deferred edge");

   // don't add a self-referential edge, this can occur during removal of

   // deferred edges

   if (from_i != to_i)

     add_edge(f, to_i, PointsToNode::DeferredEdge);

 }

 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {

   const Type *adr_type = phase->type(adr);

   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&

       adr->in(AddPNode::Address)->is_Proj() &&

       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {

     // We are computing a raw address for a store captured by an Initialize

     // compute an appropriate address type. AddP cases #3 and #5 (see below).

     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);

     assert(offs != Type::OffsetBot ||

            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),

            "offset must be a constant or it is initialization of array");

     return offs;

   }

   const TypePtr *t_ptr = adr_type->isa_ptr();

   assert(t_ptr != NULL, "must be a pointer type");

   return t_ptr->offset();

 }

 void ConnectionGraph::add_field_edge(uint from_i, uint to_i, int offset) {

   PointsToNode *f = ptnode_adr(from_i);

   PointsToNode *t = ptnode_adr(to_i);

   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");

   assert(f->node_type() == PointsToNode::JavaObject, "invalid destination of Field edge");

   assert(t->node_type() == PointsToNode::Field, "invalid destination of Field edge");

   assert (t->offset() == -1 || t->offset() == offset, "conflicting field offsets");

   t->set_offset(offset);

   add_edge(f, to_i, PointsToNode::FieldEdge);

 }

 void ConnectionGraph::set_escape_state(uint ni, PointsToNode::EscapeState es) {

   // Don't change non-escaping state of NULL pointer.

   if (ni == _noop_null || ni == _oop_null)

     return;

   PointsToNode *npt = ptnode_adr(ni);

   PointsToNode::EscapeState old_es = npt->escape_state();

   if (es > old_es)

     npt->set_escape_state(es);

 }

 void ConnectionGraph::add_node(Node *n, PointsToNode::NodeType nt,

                                PointsToNode::EscapeState es, bool done) {

   PointsToNode* ptadr = ptnode_adr(n->_idx);

   ptadr->_node = n;

   ptadr->set_node_type(nt);

   // inline set_escape_state(idx, es);

   PointsToNode::EscapeState old_es = ptadr->escape_state();

   if (es > old_es)

     ptadr->set_escape_state(es);

   if (done)

     _processed.set(n->_idx);

 }

 PointsToNode::EscapeState ConnectionGraph::escape_state(Node *n) {

   uint idx = n->_idx;

   PointsToNode::EscapeState es;

   // If we are still collecting or there were no non-escaping allocations

   // we don't know the answer yet

   if (_collecting)

     return PointsToNode::UnknownEscape;

   // if the node was created after the escape computation, return

   // UnknownEscape

   if (idx >= nodes_size())

     return PointsToNode::UnknownEscape;

   es = ptnode_adr(idx)->escape_state();

   // if we have already computed a value, return it

   if (es != PointsToNode::UnknownEscape &&

       ptnode_adr(idx)->node_type() == PointsToNode::JavaObject)

     return es;

   // PointsTo() calls n->uncast() which can return a new ideal node.

   if (n->uncast()->_idx >= nodes_size())

     return PointsToNode::UnknownEscape;

   PointsToNode::EscapeState orig_es = es;

   // compute max escape state of anything this node could point to

   for(VectorSetI i(PointsTo(n)); i.test() && es != PointsToNode::GlobalEscape; ++i) {

     uint pt = i.elem;

     PointsToNode::EscapeState pes = ptnode_adr(pt)->escape_state();

     if (pes > es)

       es = pes;

   }

   if (orig_es != es) {

     // cache the computed escape state

     assert(es > orig_es, "should have computed an escape state");

     set_escape_state(idx, es);

   } // orig_es could be PointsToNode::UnknownEscape

   return es;

 }

 VectorSet* ConnectionGraph::PointsTo(Node * n) {

   pt_ptset.Reset();

   pt_visited.Reset();

   pt_worklist.clear();

 #ifdef ASSERT

   Node *orig_n = n;

 #endif

   n = n->uncast();

   PointsToNode* npt = ptnode_adr(n->_idx);

   // If we have a JavaObject, return just that object

   if (npt->node_type() == PointsToNode::JavaObject) {

     pt_ptset.set(n->_idx);

     return &pt_ptset;

   }

 #ifdef ASSERT

   if (npt->_node == NULL) {

     if (orig_n != n)

       orig_n->dump();

     n->dump();

     assert(npt->_node != NULL, "unregistered node");

   }

 #endif

   pt_worklist.push(n->_idx);

   while(pt_worklist.length() > 0) {

     int ni = pt_worklist.pop();

     if (pt_visited.test_set(ni))

       continue;

     PointsToNode* pn = ptnode_adr(ni);

     // ensure that all inputs of a Phi have been processed

     assert(!_collecting || !pn->_node->is_Phi() || _processed.test(ni),"");

     int edges_processed = 0;

     uint e_cnt = pn->edge_count();

     for (uint e = 0; e < e_cnt; e++) {

       uint etgt = pn->edge_target(e);

       PointsToNode::EdgeType et = pn->edge_type(e);

       if (et == PointsToNode::PointsToEdge) {

         pt_ptset.set(etgt);

         edges_processed++;

       } else if (et == PointsToNode::DeferredEdge) {

         pt_worklist.push(etgt);

         edges_processed++;

       } else {

         assert(false,"neither PointsToEdge or DeferredEdge");

       }

     }

     if (edges_processed == 0) {

       // no deferred or pointsto edges found.  Assume the value was set

       // outside this method.  Add the phantom object to the pointsto set.

       pt_ptset.set(_phantom_object);

     }

   }

   return &pt_ptset;

 }

 void ConnectionGraph::remove_deferred(uint ni, GrowableArray<uint>* deferred_edges, VectorSet* visited) {

   // This method is most expensive during ConnectionGraph construction.

   // Reuse vectorSet and an additional growable array for deferred edges.

   deferred_edges->clear();

   visited->Reset();

   visited->set(ni);

   PointsToNode *ptn = ptnode_adr(ni);

   if (ptn->edge_count() == 0) {

     // No deferred or pointsto edges found.  Assume the value was set

     // outside this method.  Add edge to phantom object.

     add_pointsto_edge(ni, _phantom_object);

   }

   // Mark current edges as visited and move deferred edges to separate array.

   for (uint i = 0; i < ptn->edge_count(); ) {

     uint t = ptn->edge_target(i);

 #ifdef ASSERT

     assert(!visited->test_set(t), "expecting no duplications");

 #else

     visited->set(t);

 #endif

     if (ptn->edge_type(i) == PointsToNode::DeferredEdge) {

       ptn->remove_edge(t, PointsToNode::DeferredEdge);

       deferred_edges->append(t);

     } else {

       i++;

     }

   }

   for (int next = 0; next < deferred_edges->length(); ++next) {

     uint t = deferred_edges->at(next);

     PointsToNode *ptt = ptnode_adr(t);

     uint e_cnt = ptt->edge_count();

     if (e_cnt == 0) {

       // No deferred or pointsto edges found.  Assume the value was set

       // outside this method.  Add edge to phantom object.

       add_pointsto_edge(t, _phantom_object);

       add_pointsto_edge(ni, _phantom_object);

     }

     for (uint e = 0; e < e_cnt; e++) {

       uint etgt = ptt->edge_target(e);

       if (visited->test_set(etgt))

         continue;

       PointsToNode::EdgeType et = ptt->edge_type(e);

       if (et == PointsToNode::PointsToEdge) {

         add_pointsto_edge(ni, etgt);

         if(etgt == _phantom_object) {

           // Special case - field set outside (globally escaping).

           set_escape_state(ni, PointsToNode::GlobalEscape);

         }

       } else if (et == PointsToNode::DeferredEdge) {

         deferred_edges->append(etgt);

       } else {

         assert(false,"invalid connection graph");

       }

     }

   }

 }

 //  Add an edge to node given by "to_i" from any field of adr_i whose offset

 //  matches "offset"  A deferred edge is added if to_i is a LocalVar, and

 //  a pointsto edge is added if it is a JavaObject

 void ConnectionGraph::add_edge_from_fields(uint adr_i, uint to_i, int offs) {

   PointsToNode* an = ptnode_adr(adr_i);

   PointsToNode* to = ptnode_adr(to_i);

   bool deferred = (to->node_type() == PointsToNode::LocalVar);

   for (uint fe = 0; fe < an->edge_count(); fe++) {

     assert(an->edge_type(fe) == PointsToNode::FieldEdge, "expecting a field edge");

     int fi = an->edge_target(fe);

     PointsToNode* pf = ptnode_adr(fi);

     int po = pf->offset();

     if (po == offs || po == Type::OffsetBot || offs == Type::OffsetBot) {

       if (deferred)

         add_deferred_edge(fi, to_i);

       else

         add_pointsto_edge(fi, to_i);

     }

   }

 }

 // Add a deferred  edge from node given by "from_i" to any field of adr_i

 // whose offset matches "offset".

 void ConnectionGraph::add_deferred_edge_to_fields(uint from_i, uint adr_i, int offs) {

   PointsToNode* an = ptnode_adr(adr_i);

   bool is_alloc = an->_node->is_Allocate();

   for (uint fe = 0; fe < an->edge_count(); fe++) {

     assert(an->edge_type(fe) == PointsToNode::FieldEdge, "expecting a field edge");

     int fi = an->edge_target(fe);

     PointsToNode* pf = ptnode_adr(fi);

     int offset = pf->offset();

     if (!is_alloc) {

       // Assume the field was set outside this method if it is not Allocation

       add_pointsto_edge(fi, _phantom_object);

     }

     if (offset == offs || offset == Type::OffsetBot || offs == Type::OffsetBot) {

       add_deferred_edge(from_i, fi);

     }

   }

   // Some fields references (AddP) may still be missing

   // until Connection Graph construction is complete.

   // For example, loads from RAW pointers with offset 0

   // which don't have AddP.

   // A reference to phantom_object will be added if

   // a field reference is still missing after completing

   // Connection Graph (see remove_deferred()).

 }

 // Helper functions

 static Node* get_addp_base(Node *addp) {

   assert(addp->is_AddP(), "must be AddP");

   //

   // AddP cases for Base and Address inputs:

   // case #1. Direct object's field reference:

   //     Allocate

   //       |

   //     Proj #5 ( oop result )

   //       |

   //     CheckCastPP (cast to instance type)

   //      | |

   //     AddP  ( base == address )

   //

   // case #2. Indirect object's field reference:

   //      Phi

   //       |

   //     CastPP (cast to instance type)

   //      | |

   //     AddP  ( base == address )

   //

   // case #3. Raw object's field reference for Initialize node:

   //      Allocate

   //        |

   //      Proj #5 ( oop result )

   //  top   |

   //     \  |

   //     AddP  ( base == top )

   //

   // case #4. Array's element reference:

   //   {CheckCastPP | CastPP}

   //     |  | |

   //     |  AddP ( array's element offset )

   //     |  |

   //     AddP ( array's offset )

   //

   // case #5. Raw object's field reference for arraycopy stub call:

   //          The inline_native_clone() case when the arraycopy stub is called

   //          after the allocation before Initialize and CheckCastPP nodes.

   //      Allocate

   //        |

   //      Proj #5 ( oop result )

   //       | |

   //       AddP  ( base == address )

   //

   // case #6. Constant Pool, ThreadLocal, CastX2P or

   //          Raw object's field reference:

   //      {ConP, ThreadLocal, CastX2P, raw Load}

   //  top   |

   //     \  |

   //     AddP  ( base == top )

   //

   // case #7. Klass's field reference.

   //      LoadKlass

   //       | |

   //       AddP  ( base == address )

   //

   // case #8. narrow Klass's field reference.

   //      LoadNKlass

   //       |

   //      DecodeN

   //       | |

   //       AddP  ( base == address )

   //

   Node *base = addp->in(AddPNode::Base)->uncast();

   if (base->is_top()) { // The AddP case #3 and #6.

     base = addp->in(AddPNode::Address)->uncast();

     while (base->is_AddP()) {

       // Case #6 (unsafe access) may have several chained AddP nodes.

       assert(base->in(AddPNode::Base)->is_top(), "expected unsafe access address only");

       base = base->in(AddPNode::Address)->uncast();

     }

     assert(base->Opcode() == Op_ConP || base->Opcode() == Op_ThreadLocal ||

            base->Opcode() == Op_CastX2P || base->is_DecodeN() ||

            (base->is_Mem() && base->bottom_type() == TypeRawPtr::NOTNULL) ||

            (base->is_Proj() && base->in(0)->is_Allocate()), "sanity");

   }

   return base;

 }

 static Node* find_second_addp(Node* addp, Node* n) {

   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");

   Node* addp2 = addp->raw_out(0);

   if (addp->outcnt() == 1 && addp2->is_AddP() &&

       addp2->in(AddPNode::Base) == n &&

       addp2->in(AddPNode::Address) == addp) {

     assert(addp->in(AddPNode::Base) == n, "expecting the same base");

     //

     // Find array's offset to push it on worklist first and

     // as result process an array's element offset first (pushed second)

     // to avoid CastPP for the array's offset.

     // Otherwise the inserted CastPP (LocalVar) will point to what

     // the AddP (Field) points to. Which would be wrong since

     // the algorithm expects the CastPP has the same point as

     // as AddP's base CheckCastPP (LocalVar).

     //

     //    ArrayAllocation

     //     |

     //    CheckCastPP

     //     |

     //    memProj (from ArrayAllocation CheckCastPP)

     //     |  ||

     //     |  ||   Int (element index)

     //     |  ||    |   ConI (log(element size))

     //     |  ||    |   /

     //     |  ||   LShift

     //     |  ||  /

     //     |  AddP (array's element offset)

     //     |  |

     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))

     //     | / /

     //     AddP (array's offset)

     //      |

     //     Load/Store (memory operation on array's element)

     //

     return addp2;

   }

   return NULL;

 }

 //

 // Adjust the type and inputs of an AddP which computes the

 // address of a field of an instance

 //

 bool ConnectionGraph::split_AddP(Node *addp, Node *base,  PhaseGVN  *igvn) {

   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();

   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");

   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();

   if (t == NULL) {

     // We are computing a raw address for a store captured by an Initialize

     // compute an appropriate address type (cases #3 and #5).

     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");

     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");

     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);

     assert(offs != Type::OffsetBot, "offset must be a constant");

     t = base_t->add_offset(offs)->is_oopptr();

   }

   int inst_id =  base_t->instance_id();

   assert(!t->is_known_instance() || t->instance_id() == inst_id,

                              "old type must be non-instance or match new type");

   // The type 't' could be subclass of 'base_t'.

   // As result t->offset() could be large then base_t's size and it will

   // cause the failure in add_offset() with narrow oops since TypeOopPtr()

   // constructor verifies correctness of the offset.

   //

   // It could happened on subclass's branch (from the type profiling

   // inlining) which was not eliminated during parsing since the exactness

   // of the allocation type was not propagated to the subclass type check.

   //

   // Or the type 't' could be not related to 'base_t' at all.

   // It could happened when CHA type is different from MDO type on a dead path

   // (for example, from instanceof check) which is not collapsed during parsing.

   //

   // Do nothing for such AddP node and don't process its users since

   // this code branch will go away.

   //

   if (!t->is_known_instance() &&

       !base_t->klass()->is_subtype_of(t->klass())) {

      return false; // bail out

   }

   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();

   // Do NOT remove the next line: ensure a new alias index is allocated

   // for the instance type. Note: C++ will not remove it since the call

   // has side effect.

   int alias_idx = _compile->get_alias_index(tinst);

   igvn->set_type(addp, tinst);

   // record the allocation in the node map

   assert(ptnode_adr(addp->_idx)->_node != NULL, "should be registered");

   set_map(addp->_idx, get_map(base->_idx));

   // Set addp's Base and Address to 'base'.

   Node *abase = addp->in(AddPNode::Base);

   Node *adr   = addp->in(AddPNode::Address);

   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&

       adr->in(0)->_idx == (uint)inst_id) {

     // Skip AddP cases #3 and #5.

   } else {

     assert(!abase->is_top(), "sanity"); // AddP case #3

     if (abase != base) {

       igvn->hash_delete(addp);

       addp->set_req(AddPNode::Base, base);

       if (abase == adr) {

         addp->set_req(AddPNode::Address, base);

       } else {

         // AddP case #4 (adr is array's element offset AddP node)

 #ifdef ASSERT

         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();

         assert(adr->is_AddP() && atype != NULL &&

                atype->instance_id() == inst_id, "array's element offset should be processed first");

 #endif

       }

       igvn->hash_insert(addp);

     }

   }

   // Put on IGVN worklist since at least addp's type was changed above.

   record_for_optimizer(addp);

   return true;

 }

 //

 // Create a new version of orig_phi if necessary. Returns either the newly

 // created phi or an existing phi.  Sets create_new to indicate whether a new

 // phi was created.  Cache the last newly created phi in the node map.

 //

 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn, bool &new_created) {

   Compile *C = _compile;

   new_created = false;

   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());

   // nothing to do if orig_phi is bottom memory or matches alias_idx

   if (phi_alias_idx == alias_idx) {

     return orig_phi;

   }

   // Have we recently created a Phi for this alias index?

   PhiNode *result = get_map_phi(orig_phi->_idx);

   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {

     return result;

   }

   // Previous check may fail when the same wide memory Phi was split into Phis

   // for different memory slices. Search all Phis for this region.

   if (result != NULL) {

     Node* region = orig_phi->in(0);

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

       Node* phi = region->fast_out(i);

       if (phi->is_Phi() &&

           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {

         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");

         return phi->as_Phi();

       }

     }

   }

   if ((int)C->unique() + 2*NodeLimitFudgeFactor > MaxNodeLimit) {

     if (C->do_escape_analysis() == true && !C->failing()) {

       // Retry compilation without escape analysis.

       // If this is the first failure, the sentinel string will "stick"

       // to the Compile object, and the C2Compiler will see it and retry.

       C->record_failure(C2Compiler::retry_no_escape_analysis());

     }

     return NULL;

   }

   orig_phi_worklist.append_if_missing(orig_phi);

   const TypePtr *atype = C->get_adr_type(alias_idx);

   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);

   C->copy_node_notes_to(result, orig_phi);

   igvn->set_type(result, result->bottom_type());

   record_for_optimizer(result);

   debug_only(Node* pn = ptnode_adr(orig_phi->_idx)->_node;)

   assert(pn == NULL || pn == orig_phi, "wrong node");

   set_map(orig_phi->_idx, result);

   ptnode_adr(orig_phi->_idx)->_node = orig_phi;

   new_created = true;

   return result;

 }

 //

 // Return a new version of Memory Phi "orig_phi" with the inputs having the

 // specified alias index.

 //

 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn) {

   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");

   Compile *C = _compile;

   bool new_phi_created;

   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, igvn, new_phi_created);

   if (!new_phi_created) {

     return result;

   }

   GrowableArray<PhiNode *>  phi_list;

   GrowableArray<uint>  cur_input;

   PhiNode *phi = orig_phi;

   uint idx = 1;

   bool finished = false;

   while(!finished) {

     while (idx < phi->req()) {

       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, igvn);

       if (mem != NULL && mem->is_Phi()) {

         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, igvn, new_phi_created);

         if (new_phi_created) {

           // found an phi for which we created a new split, push current one on worklist and begin

           // processing new one

           phi_list.push(phi);

           cur_input.push(idx);

           phi = mem->as_Phi();

           result = newphi;

           idx = 1;

           continue;

         } else {

           mem = newphi;

         }

       }

       if (C->failing()) {

         return NULL;

       }

       result->set_req(idx++, mem);

     }

 #ifdef ASSERT

     // verify that the new Phi has an input for each input of the original

     assert( phi->req() == result->req(), "must have same number of inputs.");

     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");

 #endif

     // Check if all new phi's inputs have specified alias index.

     // Otherwise use old phi.

     for (uint i = 1; i < phi->req(); i++) {

       Node* in = result->in(i);

       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");

     }

     // we have finished processing a Phi, see if there are any more to do

     finished = (phi_list.length() == 0 );

     if (!finished) {

       phi = phi_list.pop();

       idx = cur_input.pop();

       PhiNode *prev_result = get_map_phi(phi->_idx);

       prev_result->set_req(idx++, result);

       result = prev_result;

     }

   }

   return result;

 }

 //

 // The next methods are derived from methods in MemNode.

 //

 static Node *step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {

   Node *mem = mmem;

   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally

   // means an array I have not precisely typed yet.  Do not do any

   // alias stuff with it any time soon.

   if( toop->base() != Type::AnyPtr &&

       !(toop->klass() != NULL &&

         toop->klass()->is_java_lang_Object() &&

         toop->offset() == Type::OffsetBot) ) {

     mem = mmem->memory_at(alias_idx);

     // Update input if it is progress over what we have now

   }

   return mem;

 }

 //

 // Move memory users to their memory slices.

 //

 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis, PhaseGVN *igvn) {

   Compile* C = _compile;

   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();

   assert(tp != NULL, "ptr type");

   int alias_idx = C->get_alias_index(tp);

   int general_idx = C->get_general_index(alias_idx);

   // Move users first

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

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

     if (use->is_MergeMem()) {

       MergeMemNode* mmem = use->as_MergeMem();

       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");

       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {

         continue; // Nothing to do

       }

       // Replace previous general reference to mem node.

       uint orig_uniq = C->unique();

       Node* m = find_inst_mem(n, general_idx, orig_phis, igvn);

       assert(orig_uniq == C->unique(), "no new nodes");

       mmem->set_memory_at(general_idx, m);

       --imax;

       --i;

     } else if (use->is_MemBar()) {

       assert(!use->is_Initialize(), "initializing stores should not be moved");

       if (use->req() > MemBarNode::Precedent &&

           use->in(MemBarNode::Precedent) == n) {

         // Don't move related membars.

         record_for_optimizer(use);

         continue;

       }

       tp = use->as_MemBar()->adr_type()->isa_ptr();

       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||

           alias_idx == general_idx) {

         continue; // Nothing to do

       }

       // Move to general memory slice.

       uint orig_uniq = C->unique();

       Node* m = find_inst_mem(n, general_idx, orig_phis, igvn);

       assert(orig_uniq == C->unique(), "no new nodes");

       igvn->hash_delete(use);

       imax -= use->replace_edge(n, m);

       igvn->hash_insert(use);

       record_for_optimizer(use);

       --i;

 #ifdef ASSERT

     } else if (use->is_Mem()) {

       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {

         // Don't move related cardmark.

         continue;

       }

       // Memory nodes should have new memory input.

       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();

       assert(tp != NULL, "ptr type");

       int idx = C->get_alias_index(tp);

       assert(get_map(use->_idx) != NULL || idx == alias_idx,

              "Following memory nodes should have new memory input or be on the same memory slice");

     } else if (use->is_Phi()) {

       // Phi nodes should be split and moved already.

       tp = use->as_Phi()->adr_type()->isa_ptr();

       assert(tp != NULL, "ptr type");

       int idx = C->get_alias_index(tp);

       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");

     } else {

       use->dump();

       assert(false, "should not be here");

 #endif

     }

   }

 }

 //

 // Search memory chain of "mem" to find a MemNode whose address

 // is the specified alias index.

 //

 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, PhaseGVN *phase) {

   if (orig_mem == NULL)

     return orig_mem;

   Compile* C = phase->C;

   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();

   bool is_instance = (toop != NULL) && toop->is_known_instance();

   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);

   Node *prev = NULL;

   Node *result = orig_mem;

   while (prev != result) {

     prev = result;

     if (result == start_mem)

       break;  // hit one of our sentinels

     if (result->is_Mem()) {

       const Type *at = phase->type(result->in(MemNode::Address));

       if (at == Type::TOP)

         break; // Dead

       assert (at->isa_ptr() != NULL, "pointer type required.");

       int idx = C->get_alias_index(at->is_ptr());

       if (idx == alias_idx)

         break; // Found

       if (!is_instance && (at->isa_oopptr() == NULL ||

                            !at->is_oopptr()->is_known_instance())) {

         break; // Do not skip store to general memory slice.

       }

       result = result->in(MemNode::Memory);

     }

     if (!is_instance)

       continue;  // don't search further for non-instance types

     // skip over a call which does not affect this memory slice

     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {

       Node *proj_in = result->in(0);

       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {

         break;  // hit one of our sentinels

       } else if (proj_in->is_Call()) {

         CallNode *call = proj_in->as_Call();

         if (!call->may_modify(toop, phase)) {

           result = call->in(TypeFunc::Memory);

         }

       } else if (proj_in->is_Initialize()) {

         AllocateNode* alloc = proj_in->as_Initialize()->allocation();

         // Stop if this is the initialization for the object instance which

         // which contains this memory slice, otherwise skip over it.

         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {

           result = proj_in->in(TypeFunc::Memory);

         }

       } else if (proj_in->is_MemBar()) {

         result = proj_in->in(TypeFunc::Memory);

       }

     } else if (result->is_MergeMem()) {

       MergeMemNode *mmem = result->as_MergeMem();

       result = step_through_mergemem(mmem, alias_idx, toop);

       if (result == mmem->base_memory()) {

         // Didn't find instance memory, search through general slice recursively.

         result = mmem->memory_at(C->get_general_index(alias_idx));

         result = find_inst_mem(result, alias_idx, orig_phis, phase);

         if (C->failing()) {

           return NULL;

         }

         mmem->set_memory_at(alias_idx, result);

       }

     } else if (result->is_Phi() &&

                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {

       Node *un = result->as_Phi()->unique_input(phase);

       if (un != NULL) {

         orig_phis.append_if_missing(result->as_Phi());

         result = un;

       } else {

         break;

       }

     } else if (result->is_ClearArray()) {

       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), phase)) {

         // Can not bypass initialization of the instance

         // we are looking for.

         break;

       }

       // Otherwise skip it (the call updated 'result' value).

     } else if (result->Opcode() == Op_SCMemProj) {

       assert(result->in(0)->is_LoadStore(), "sanity");

       const Type *at = phase->type(result->in(0)->in(MemNode::Address));

       if (at != Type::TOP) {

         assert (at->isa_ptr() != NULL, "pointer type required.");

         int idx = C->get_alias_index(at->is_ptr());

         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");

         break;

       }

       result = result->in(0)->in(MemNode::Memory);

     }

   }

   if (result->is_Phi()) {

     PhiNode *mphi = result->as_Phi();

     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");

     const TypePtr *t = mphi->adr_type();

     if (!is_instance) {

       // Push all non-instance Phis on the orig_phis worklist to update inputs

       // during Phase 4 if needed.

       orig_phis.append_if_missing(mphi);

     } else if (C->get_alias_index(t) != alias_idx) {

       // Create a new Phi with the specified alias index type.

       result = split_memory_phi(mphi, alias_idx, orig_phis, phase);

     }

   }

   // the result is either MemNode, PhiNode, InitializeNode.

   return result;

 }

 //

 //  Convert the types of unescaped object to instance types where possible,

 //  propagate the new type information through the graph, and update memory

 //  edges and MergeMem inputs to reflect the new type.

 //

 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.

 //  The processing is done in 4 phases:

 //

 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance

 //            types for the CheckCastPP for allocations where possible.

 //            Propagate the the new types through users as follows:

 //               casts and Phi:  push users on alloc_worklist

 //               AddP:  cast Base and Address inputs to the instance type

 //                      push any AddP users on alloc_worklist and push any memnode

 //                      users onto memnode_worklist.

 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and

 //            search the Memory chain for a store with the appropriate type

 //            address type.  If a Phi is found, create a new version with

 //            the appropriate memory slices from each of the Phi inputs.

 //            For stores, process the users as follows:

 //               MemNode:  push on memnode_worklist

 //               MergeMem: push on mergemem_worklist

 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice

 //            moving the first node encountered of each  instance type to the

 //            the input corresponding to its alias index.

 //            appropriate memory slice.

 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.

 //

 // In the following example, the CheckCastPP nodes are the cast of allocation

 // results and the allocation of node 29 is unescaped and eligible to be an

 // instance type.

 //

 // We start with:

 //

 //     7 Parm #memory

 //    10  ConI  "12"

 //    19  CheckCastPP   "Foo"

 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4

 //    29  CheckCastPP   "Foo"

 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4

 //

 //    40  StoreP  25   7  20   ... alias_index=4

 //    50  StoreP  35  40  30   ... alias_index=4

 //    60  StoreP  45  50  20   ... alias_index=4

 //    70  LoadP    _  60  30   ... alias_index=4

 //    80  Phi     75  50  60   Memory alias_index=4

 //    90  LoadP    _  80  30   ... alias_index=4

 //   100  LoadP    _  80  20   ... alias_index=4

 //

 //

 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24

 // and creating a new alias index for node 30.  This gives:

 //

 //     7 Parm #memory

 //    10  ConI  "12"

 //    19  CheckCastPP   "Foo"

 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4

 //    29  CheckCastPP   "Foo"  iid=24

 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24

 //

 //    40  StoreP  25   7  20   ... alias_index=4

 //    50  StoreP  35  40  30   ... alias_index=6

 //    60  StoreP  45  50  20   ... alias_index=4

 //    70  LoadP    _  60  30   ... alias_index=6

 //    80  Phi     75  50  60   Memory alias_index=4

 //    90  LoadP    _  80  30   ... alias_index=6

 //   100  LoadP    _  80  20   ... alias_index=4

 //

 // In phase 2, new memory inputs are computed for the loads and stores,

 // And a new version of the phi is created.  In phase 4, the inputs to

 // node 80 are updated and then the memory nodes are updated with the

 // values computed in phase 2.  This results in:

 //

 //     7 Parm #memory

 //    10  ConI  "12"

 //    19  CheckCastPP   "Foo"

 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4

 //    29  CheckCastPP   "Foo"  iid=24

 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24

 //

 //    40  StoreP  25  7   20   ... alias_index=4

 //    50  StoreP  35  7   30   ... alias_index=6

 //    60  StoreP  45  40  20   ... alias_index=4

 //    70  LoadP    _  50  30   ... alias_index=6

 //    80  Phi     75  40  60   Memory alias_index=4

 //   120  Phi     75  50  50   Memory alias_index=6

 //    90  LoadP    _ 120  30   ... alias_index=6

 //   100  LoadP    _  80  20   ... alias_index=4

 //

 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {

   GrowableArray<Node *>  memnode_worklist;

   GrowableArray<PhiNode *>  orig_phis;

   PhaseIterGVN  *igvn = _igvn;

   uint new_index_start = (uint) _compile->num_alias_types();

   Arena* arena = Thread::current()->resource_area();

   VectorSet visited(arena);

   //  Phase 1:  Process possible allocations from alloc_worklist.

   //  Create instance types for the CheckCastPP for allocations where possible.

   //

   // (Note: don't forget to change the order of the second AddP node on

   //  the alloc_worklist if the order of the worklist processing is changed,

   //  see the comment in find_second_addp().)

   //

   while (alloc_worklist.length() != 0) {

     Node *n = alloc_worklist.pop();

     uint ni = n->_idx;

     const TypeOopPtr* tinst = NULL;

     if (n->is_Call()) {

       CallNode *alloc = n->as_Call();

       // copy escape information to call node

       PointsToNode* ptn = ptnode_adr(alloc->_idx);

       PointsToNode::EscapeState es = escape_state(alloc);

       // We have an allocation or call which returns a Java object,

       // see if it is unescaped.

       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())

         continue;

       // Find CheckCastPP for the allocate or for the return value of a call

       n = alloc->result_cast();

       if (n == NULL) {            // No uses except Initialize node

         if (alloc->is_Allocate()) {

           // Set the scalar_replaceable flag for allocation

           // so it could be eliminated if it has no uses.

           alloc->as_Allocate()->_is_scalar_replaceable = true;

         }

         continue;

       }

       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.

         assert(!alloc->is_Allocate(), "allocation should have unique type");

         continue;

       }

       // The inline code for Object.clone() casts the allocation result to

       // java.lang.Object and then to the actual type of the allocated

       // object. Detect this case and use the second cast.

       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when

       // the allocation result is cast to java.lang.Object and then

       // to the actual Array type.

       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL

           && (alloc->is_AllocateArray() ||

               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {

         Node *cast2 = NULL;

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

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

           if (use->is_CheckCastPP()) {

             cast2 = use;

             break;

           }

         }

         if (cast2 != NULL) {

           n = cast2;

         } else {

           // Non-scalar replaceable if the allocation type is unknown statically

           // (reflection allocation), the object can't be restored during

           // deoptimization without precise type.

           continue;

         }

       }

       if (alloc->is_Allocate()) {

         // Set the scalar_replaceable flag for allocation

         // so it could be eliminated.

         alloc->as_Allocate()->_is_scalar_replaceable = true;

       }

       set_escape_state(n->_idx, es); // CheckCastPP escape state

       // in order for an object to be scalar-replaceable, it must be:

       //   - a direct allocation (not a call returning an object)

       //   - non-escaping

       //   - eligible to be a unique type

       //   - not determined to be ineligible by escape analysis

       assert(ptnode_adr(alloc->_idx)->_node != NULL &&

              ptnode_adr(n->_idx)->_node != NULL, "should be registered");

       set_map(alloc->_idx, n);

       set_map(n->_idx, alloc);

       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();

       if (t == NULL)

         continue;  // not a TypeOopPtr

       tinst = t->cast_to_exactness(true)->is_oopptr()->cast_to_instance_id(ni);

       igvn->hash_delete(n);

       igvn->set_type(n,  tinst);

       n->raise_bottom_type(tinst);

       igvn->hash_insert(n);

       record_for_optimizer(n);

       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {

         // First, put on the worklist all Field edges from Connection Graph

         // which is more accurate then putting immediate users from Ideal Graph.

         for (uint e = 0; e < ptn->edge_count(); e++) {

           Node *use = ptnode_adr(ptn->edge_target(e))->_node;

           assert(ptn->edge_type(e) == PointsToNode::FieldEdge && use->is_AddP(),

                  "only AddP nodes are Field edges in CG");

           if (use->outcnt() > 0) { // Don't process dead nodes

             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));

             if (addp2 != NULL) {

               assert(alloc->is_AllocateArray(),"array allocation was expected");

               alloc_worklist.append_if_missing(addp2);

             }

             alloc_worklist.append_if_missing(use);

           }

         }

         // An allocation may have an Initialize which has raw stores. Scan

         // the users of the raw allocation result and push AddP users

         // on alloc_worklist.

         Node *raw_result = alloc->proj_out(TypeFunc::Parms);

         assert (raw_result != NULL, "must have an allocation result");

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

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

           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes

             Node* addp2 = find_second_addp(use, raw_result);

             if (addp2 != NULL) {

               assert(alloc->is_AllocateArray(),"array allocation was expected");

               alloc_worklist.append_if_missing(addp2);

             }

             alloc_worklist.append_if_missing(use);

           } else if (use->is_MemBar()) {

             memnode_worklist.append_if_missing(use);

           }

         }

       }

     } else if (n->is_AddP()) {

       VectorSet* ptset = PointsTo(get_addp_base(n));

       assert(ptset->Size() == 1, "AddP address is unique");

       uint elem = ptset->getelem(); // Allocation node's index

       if (elem == _phantom_object) {

         assert(false, "escaped allocation");

         continue; // Assume the value was set outside this method.

       }

       Node *base = get_map(elem);  // CheckCastPP node

       if (!split_AddP(n, base, igvn)) continue; // wrong type from dead path

       tinst = igvn->type(base)->isa_oopptr();

     } else if (n->is_Phi() ||

                n->is_CheckCastPP() ||

                n->is_EncodeP() ||

                n->is_DecodeN() ||

                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {

       if (visited.test_set(n->_idx)) {

         assert(n->is_Phi(), "loops only through Phi's");

         continue;  // already processed

       }

       VectorSet* ptset = PointsTo(n);

       if (ptset->Size() == 1) {

         uint elem = ptset->getelem(); // Allocation node's index

         if (elem == _phantom_object) {

           assert(false, "escaped allocation");

           continue; // Assume the value was set outside this method.

         }

         Node *val = get_map(elem);   // CheckCastPP node

         TypeNode *tn = n->as_Type();

         tinst = igvn->type(val)->isa_oopptr();

         assert(tinst != NULL && tinst->is_known_instance() &&

                (uint)tinst->instance_id() == elem , "instance type expected.");

         const Type *tn_type = igvn->type(tn);

         const TypeOopPtr *tn_t;

         if (tn_type->isa_narrowoop()) {

           tn_t = tn_type->make_ptr()->isa_oopptr();

         } else {

           tn_t = tn_type->isa_oopptr();

         }

         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {

           if (tn_type->isa_narrowoop()) {

             tn_type = tinst->make_narrowoop();

           } else {

             tn_type = tinst;

           }

           igvn->hash_delete(tn);

           igvn->set_type(tn, tn_type);

           tn->set_type(tn_type);

           igvn->hash_insert(tn);

           record_for_optimizer(n);

         } else {

           assert(tn_type == TypePtr::NULL_PTR ||

                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),

                  "unexpected type");

           continue; // Skip dead path with different type

         }

       }

     } else {

       debug_only(n->dump();)

       assert(false, "EA: unexpected node");

       continue;

     }

     // push allocation's users on appropriate worklist

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

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

       if(use->is_Mem() && use->in(MemNode::Address) == n) {

         // Load/store to instance's field

         memnode_worklist.append_if_missing(use);

       } else if (use->is_MemBar()) {

         memnode_worklist.append_if_missing(use);

       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes

         Node* addp2 = find_second_addp(use, n);

         if (addp2 != NULL) {

           alloc_worklist.append_if_missing(addp2);

         }

         alloc_worklist.append_if_missing(use);

       } else if (use->is_Phi() ||

                  use->is_CheckCastPP() ||

                  use->is_EncodeP() ||

                  use->is_DecodeN() ||

                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {

         alloc_worklist.append_if_missing(use);

 #ifdef ASSERT

       } else if (use->is_Mem()) {

         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");

       } else if (use->is_MergeMem()) {

         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");

       } else if (use->is_SafePoint()) {

         // Look for MergeMem nodes for calls which reference unique allocation

         // (through CheckCastPP nodes) even for debug info.

         Node* m = use->in(TypeFunc::Memory);

         if (m->is_MergeMem()) {

           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");

         }

       } else {

         uint op = use->Opcode();

         if (!(op == Op_CmpP || op == Op_Conv2B ||

               op == Op_CastP2X || op == Op_StoreCM ||

               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||

               op == Op_StrEquals || op == Op_StrIndexOf)) {

           n->dump();

           use->dump();

           assert(false, "EA: missing allocation reference path");

         }

 #endif

       }

     }

   }

   // New alias types were created in split_AddP().

   uint new_index_end = (uint) _compile->num_alias_types();

   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and

   //            compute new values for Memory inputs  (the Memory inputs are not

   //            actually updated until phase 4.)

   if (memnode_worklist.length() == 0)

     return;  // nothing to do

   while (memnode_worklist.length() != 0) {

     Node *n = memnode_worklist.pop();

     if (visited.test_set(n->_idx))

       continue;

     if (n->is_Phi() || n->is_ClearArray()) {

       // we don't need to do anything, but the users must be pushed

     } else if (n->is_MemBar()) { // Initialize, MemBar nodes

       // we don't need to do anything, but the users must be pushed

       n = n->as_MemBar()->proj_out(TypeFunc::Memory);

       if (n == NULL)

         continue;

     } else {

       assert(n->is_Mem(), "memory node required.");

       Node *addr = n->in(MemNode::Address);

       const Type *addr_t = igvn->type(addr);

       if (addr_t == Type::TOP)

         continue;

       assert (addr_t->isa_ptr() != NULL, "pointer type required.");

       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());

       assert ((uint)alias_idx < new_index_end, "wrong alias index");

       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis, igvn);

       if (_compile->failing()) {

         return;

       }

       if (mem != n->in(MemNode::Memory)) {

         // We delay the memory edge update since we need old one in

         // MergeMem code below when instances memory slices are separated.

         debug_only(Node* pn = ptnode_adr(n->_idx)->_node;)

         assert(pn == NULL || pn == n, "wrong node");

         set_map(n->_idx, mem);

         ptnode_adr(n->_idx)->_node = n;

       }

       if (n->is_Load()) {

         continue;  // don't push users

       } else if (n->is_LoadStore()) {

         // get the memory projection

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

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

           if (use->Opcode() == Op_SCMemProj) {

             n = use;

             break;

           }

         }

         assert(n->Opcode() == Op_SCMemProj, "memory projection required");

       }

     }

     // push user on appropriate worklist

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

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

       if (use->is_Phi() || use->is_ClearArray()) {

         memnode_worklist.append_if_missing(use);

       } else if(use->is_Mem() && use->in(MemNode::Memory) == n) {

         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores

           continue;

         memnode_worklist.append_if_missing(use);

       } else if (use->is_MemBar()) {

         memnode_worklist.append_if_missing(use);

 #ifdef ASSERT

       } else if(use->is_Mem()) {

         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");

       } else if (use->is_MergeMem()) {

         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");

       } else {

         uint op = use->Opcode();

         if (!(op == Op_StoreCM ||

               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&

                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||

               op == Op_AryEq || op == Op_StrComp ||

               op == Op_StrEquals || op == Op_StrIndexOf)) {

           n->dump();

           use->dump();

           assert(false, "EA: missing memory path");

         }

 #endif

       }

     }

   }

   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.

   //            Walk each memory slice moving the first node encountered of each

   //            instance type to the the input corresponding to its alias index.

   uint length = _mergemem_worklist.length();

   for( uint next = 0; next < length; ++next ) {

     MergeMemNode* nmm = _mergemem_worklist.at(next);

     assert(!visited.test_set(nmm->_idx), "should not be visited before");

     // Note: we don't want to use MergeMemStream here because we only want to

     // scan inputs which exist at the start, not ones we add during processing.

     // Note 2: MergeMem may already contains instance memory slices added

     // during find_inst_mem() call when memory nodes were processed above.

     igvn->hash_delete(nmm);

     uint nslices = nmm->req();

     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {

       Node* mem = nmm->in(i);

       Node* cur = NULL;

       if (mem == NULL || mem->is_top())

         continue;

       // First, update mergemem by moving memory nodes to corresponding slices

       // if their type became more precise since this mergemem was created.

       while (mem->is_Mem()) {

         const Type *at = igvn->type(mem->in(MemNode::Address));

         if (at != Type::TOP) {

           assert (at->isa_ptr() != NULL, "pointer type required.");

           uint idx = (uint)_compile->get_alias_index(at->is_ptr());

           if (idx == i) {

             if (cur == NULL)

               cur = mem;

           } else {

             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {

               nmm->set_memory_at(idx, mem);

             }

           }

         }

         mem = mem->in(MemNode::Memory);

       }

       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);

       // Find any instance of the current type if we haven't encountered

       // already a memory slice of the instance along the memory chain.

       for (uint ni = new_index_start; ni < new_index_end; ni++) {

         if((uint)_compile->get_general_index(ni) == i) {

           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);

           if (nmm->is_empty_memory(m)) {

             Node* result = find_inst_mem(mem, ni, orig_phis, igvn);

             if (_compile->failing()) {

               return;

             }

             nmm->set_memory_at(ni, result);

           }

         }

       }

     }

     // Find the rest of instances values

     for (uint ni = new_index_start; ni < new_index_end; ni++) {

       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();

       Node* result = step_through_mergemem(nmm, ni, tinst);

       if (result == nmm->base_memory()) {

         // Didn't find instance memory, search through general slice recursively.

         result = nmm->memory_at(_compile->get_general_index(ni));

         result = find_inst_mem(result, ni, orig_phis, igvn);

         if (_compile->failing()) {

           return;

         }

         nmm->set_memory_at(ni, result);

       }

     }

     igvn->hash_insert(nmm);

     record_for_optimizer(nmm);

   }

   //  Phase 4:  Update the inputs of non-instance memory Phis and

   //            the Memory input of memnodes

   // First update the inputs of any non-instance Phi's from

   // which we split out an instance Phi.  Note we don't have

   // to recursively process Phi's encounted on the input memory

   // chains as is done in split_memory_phi() since they  will

   // also be processed here.

   for (int j = 0; j < orig_phis.length(); j++) {

     PhiNode *phi = orig_phis.at(j);

     int alias_idx = _compile->get_alias_index(phi->adr_type());

     igvn->hash_delete(phi);

     for (uint i = 1; i < phi->req(); i++) {

       Node *mem = phi->in(i);

       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis, igvn);

       if (_compile->failing()) {

         return;

       }

       if (mem != new_mem) {

         phi->set_req(i, new_mem);

       }

     }

     igvn->hash_insert(phi);

     record_for_optimizer(phi);

   }

   // Update the memory inputs of MemNodes with the value we computed

   // in Phase 2 and move stores memory users to corresponding memory slices.

   // Disable memory split verification code until the fix for 6984348.

   // Currently it produces false negative results since it does not cover all cases.

 #if 0 // ifdef ASSERT

   visited.Reset();

   Node_Stack old_mems(arena, _compile->unique() >> 2);

 #endif

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

     Node *nmem = get_map(i);

     if (nmem != NULL) {

       Node *n = ptnode_adr(i)->_node;

       assert(n != NULL, "sanity");

       if (n->is_Mem()) {

 #if 0 // ifdef ASSERT

         Node* old_mem = n->in(MemNode::Memory);

         if (!visited.test_set(old_mem->_idx)) {

           old_mems.push(old_mem, old_mem->outcnt());

         }

 #endif

         assert(n->in(MemNode::Memory) != nmem, "sanity");

         if (!n->is_Load()) {

           // Move memory users of a store first.

           move_inst_mem(n, orig_phis, igvn);

         }

         // Now update memory input

         igvn->hash_delete(n);

         n->set_req(MemNode::Memory, nmem);

         igvn->hash_insert(n);

         record_for_optimizer(n);

       } else {

         assert(n->is_Allocate() || n->is_CheckCastPP() ||

                n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");

       }

     }

   }

 #if 0 // ifdef ASSERT

   // Verify that memory was split correctly

   while (old_mems.is_nonempty()) {

     Node* old_mem = old_mems.node();

     uint  old_cnt = old_mems.index();

     old_mems.pop();

     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");

   }

 #endif

 }

 bool ConnectionGraph::has_candidates(Compile *C) {

   // EA brings benefits only when the code has allocations and/or locks which

   // are represented by ideal Macro nodes.

   int cnt = C->macro_count();

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

     Node *n = C->macro_node(i);

     if ( n->is_Allocate() )

       return true;

     if( n->is_Lock() ) {

       Node* obj = n->as_Lock()->obj_node()->uncast();

       if( !(obj->is_Parm() || obj->is_Con()) )

         return true;

     }

   }

   return false;

 }

 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {

   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction

   // to create space for them in ConnectionGraph::_nodes[].

   Node* oop_null = igvn->zerocon(T_OBJECT);

   Node* noop_null = igvn->zerocon(T_NARROWOOP);

   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);

   // Perform escape analysis

   if (congraph->compute_escape()) {

     // There are non escaping objects.

     C->set_congraph(congraph);

   }

   // Cleanup.

   if (oop_null->outcnt() == 0)

     igvn->hash_delete(oop_null);

   if (noop_null->outcnt() == 0)

     igvn->hash_delete(noop_null);

 }

 bool ConnectionGraph::compute_escape() {

   Compile* C = _compile;

   // 1. Populate Connection Graph (CG) with Ideal nodes.

   Unique_Node_List worklist_init;

   worklist_init.map(C->unique(), NULL);  // preallocate space

   // Initialize worklist

   if (C->root() != NULL) {

     worklist_init.push(C->root());

   }

   GrowableArray<Node*> alloc_worklist;

   GrowableArray<Node*> addp_worklist;

   GrowableArray<Node*> ptr_cmp_worklist;

   PhaseGVN* igvn = _igvn;

   bool has_allocations = false;

   // Push all useful nodes onto CG list and set their type.

   for( uint next = 0; next < worklist_init.size(); ++next ) {

     Node* n = worklist_init.at(next);

     record_for_escape_analysis(n, igvn);

     // Only allocations and java static calls results are checked

     // for an escape status. See process_call_result() below.

     if (n->is_Allocate() || n->is_CallStaticJava() &&

         ptnode_adr(n->_idx)->node_type() == PointsToNode::JavaObject) {

       has_allocations = true;

       if (n->is_Allocate())

         alloc_worklist.append(n);

     } else if(n->is_AddP()) {

       // Collect address nodes. Use them during stage 3 below

       // to build initial connection graph field edges.

       addp_worklist.append(n);

     } else if (n->is_MergeMem()) {

       // Collect all MergeMem nodes to add memory slices for

       // scalar replaceable objects in split_unique_types().

       _mergemem_worklist.append(n->as_MergeMem());

     } else if (OptimizePtrCompare && n->is_Cmp() &&

                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {

       // Compare pointers nodes

       ptr_cmp_worklist.append(n);

     }

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

       Node* m = n->fast_out(i);   // Get user

       worklist_init.push(m);

     }

   }

   if (!has_allocations) {

     _collecting = false;

     return false; // Nothing to do.

   }

   // 2. First pass to create simple CG edges (doesn't require to walk CG).

   uint delayed_size = _delayed_worklist.size();

   for( uint next = 0; next < delayed_size; ++next ) {

     Node* n = _delayed_worklist.at(next);

     build_connection_graph(n, igvn);

   }

   // 3. Pass to create initial fields edges (JavaObject -F-> AddP)

   //    to reduce number of iterations during stage 4 below.

   uint addp_length = addp_worklist.length();

   for( uint next = 0; next < addp_length; ++next ) {

     Node* n = addp_worklist.at(next);

     Node* base = get_addp_base(n);

     if (base->is_Proj() && base->in(0)->is_Call())

       base = base->in(0);

     PointsToNode::NodeType nt = ptnode_adr(base->_idx)->node_type();

     if (nt == PointsToNode::JavaObject) {

       build_connection_graph(n, igvn);

     }

   }

   GrowableArray<int> cg_worklist;

   cg_worklist.append(_phantom_object);

   GrowableArray<uint>  worklist;

   // 4. Build Connection Graph which need

   //    to walk the connection graph.

   _progress = false;

   for (uint ni = 0; ni < nodes_size(); ni++) {

     PointsToNode* ptn = ptnode_adr(ni);

     Node *n = ptn->_node;

     if (n != NULL) { // Call, AddP, LoadP, StoreP

       build_connection_graph(n, igvn);

       if (ptn->node_type() != PointsToNode::UnknownType)

         cg_worklist.append(n->_idx); // Collect CG nodes

       if (!_processed.test(n->_idx))

         worklist.append(n->_idx); // Collect C/A/L/S nodes

     }

   }

   // After IGVN user nodes may have smaller _idx than

   // their inputs so they will be processed first in

   // previous loop. Because of that not all Graph

   // edges will be created. Walk over interesting

   // nodes again until no new edges are created.

   //

   // Normally only 1-3 passes needed to build

   // Connection Graph depending on graph complexity.

   // Observed 8 passes in jvm2008 compiler.compiler.

   // Set limit to 20 to catch situation when something

   // did go wrong and recompile the method without EA.

 #define CG_BUILD_ITER_LIMIT 20

   uint length = worklist.length();

   int iterations = 0;

   while(_progress && (iterations++ < CG_BUILD_ITER_LIMIT)) {

     _progress = false;

     for( uint next = 0; next < length; ++next ) {

       int ni = worklist.at(next);

       PointsToNode* ptn = ptnode_adr(ni);

       Node* n = ptn->_node;

       assert(n != NULL, "should be known node");

       build_connection_graph(n, igvn);

     }

   }

   if (iterations >= CG_BUILD_ITER_LIMIT) {

     assert(iterations < CG_BUILD_ITER_LIMIT,

            err_msg("infinite EA connection graph build with %d nodes and worklist size %d",

            nodes_size(), length));

     // Possible infinite build_connection_graph loop,

     // retry compilation without escape analysis.

     C->record_failure(C2Compiler::retry_no_escape_analysis());

     _collecting = false;

     return false;

   }

 #undef CG_BUILD_ITER_LIMIT

   Arena* arena = Thread::current()->resource_area();

   VectorSet visited(arena);

   // 5. Find fields initializing values for not escaped allocations

   uint alloc_length = alloc_worklist.length();

   for (uint next = 0; next < alloc_length; ++next) {

     Node* n = alloc_worklist.at(next);

     if (ptnode_adr(n->_idx)->escape_state() == PointsToNode::NoEscape) {

       find_init_values(n, &visited, igvn);

     }

   }

   worklist.clear();

   // 6. Remove deferred edges from the graph.

   uint cg_length = cg_worklist.length();

   for (uint next = 0; next < cg_length; ++next) {

     int ni = cg_worklist.at(next);

     PointsToNode* ptn = ptnode_adr(ni);

     PointsToNode::NodeType nt = ptn->node_type();

     if (nt == PointsToNode::LocalVar || nt == PointsToNode::Field) {

       remove_deferred(ni, &worklist, &visited);

     }

   }

   // 7. Adjust escape state of nonescaping objects.

   for (uint next = 0; next < addp_length; ++next) {

     Node* n = addp_worklist.at(next);

     adjust_escape_state(n);

   }

   // 8. Propagate escape states.

   worklist.clear();

   // mark all nodes reachable from GlobalEscape nodes

   (void)propagate_escape_state(&cg_worklist, &worklist, PointsToNode::GlobalEscape);

   // mark all nodes reachable from ArgEscape nodes

   bool has_non_escaping_obj = propagate_escape_state(&cg_worklist, &worklist, PointsToNode::ArgEscape);

   // push all NoEscape nodes on the worklist

   for( uint next = 0; next < cg_length; ++next ) {

     int nk = cg_worklist.at(next);

     if (ptnode_adr(nk)->escape_state() == PointsToNode::NoEscape)

       worklist.push(nk);

   }

   alloc_worklist.clear();

   // mark all nodes reachable from NoEscape nodes

   while(worklist.length() > 0) {

     uint nk = worklist.pop();

     PointsToNode* ptn = ptnode_adr(nk);

     if (ptn->node_type() == PointsToNode::JavaObject &&

         !(nk == _noop_null || nk == _oop_null))

       has_non_escaping_obj = true; // Non Escape

     Node* n = ptn->_node;

     bool scalar_replaceable = ptn->scalar_replaceable();

     if (n->is_Allocate() && scalar_replaceable) {

       // Push scalar replaceable allocations on alloc_worklist

       // for processing in split_unique_types(). Note,

       // following code may change scalar_replaceable value.

       alloc_worklist.append(n);

     }

     uint e_cnt = ptn->edge_count();

     for (uint ei = 0; ei < e_cnt; ei++) {

       uint npi = ptn->edge_target(ei);

       PointsToNode *np = ptnode_adr(npi);

       if (np->escape_state() < PointsToNode::NoEscape) {

         set_escape_state(npi, PointsToNode::NoEscape);

         if (!scalar_replaceable) {

           np->set_scalar_replaceable(false);

         }

         worklist.push(npi);

       } else if (np->scalar_replaceable() && !scalar_replaceable) {

         // Propagate scalar_replaceable value.

         np->set_scalar_replaceable(false);

         worklist.push(npi);

       }

     }

   }

   _collecting = false;

   assert(C->unique() == nodes_size(), "there should be no new ideal nodes during ConnectionGraph build");

   assert(ptnode_adr(_oop_null)->escape_state() == PointsToNode::NoEscape, "sanity");

   if (UseCompressedOops) {

     assert(ptnode_adr(_noop_null)->escape_state() == PointsToNode::NoEscape, "sanity");

   }

   if (EliminateLocks && has_non_escaping_obj) {

     // Mark locks before changing ideal graph.

     int cnt = C->macro_count();

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

       Node *n = C->macro_node(i);

       if (n->is_AbstractLock()) { // Lock and Unlock nodes

         AbstractLockNode* alock = n->as_AbstractLock();

         if (!alock->is_eliminated()) {

           PointsToNode::EscapeState es = escape_state(alock->obj_node());

           assert(es != PointsToNode::UnknownEscape, "should know");

           if (es != PointsToNode::UnknownEscape && es != PointsToNode::GlobalEscape) {

             // Mark it eliminated

             alock->set_eliminated();

           }

         }

       }

     }

   }

   if (OptimizePtrCompare && has_non_escaping_obj) {

     // Add ConI(#CC_GT) and ConI(#CC_EQ).

     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);

     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);

     // Optimize objects compare.

     while (ptr_cmp_worklist.length() != 0) {

       Node *n = ptr_cmp_worklist.pop();

       Node *res = optimize_ptr_compare(n);

       if (res != NULL) {

 #ifndef PRODUCT

         if (PrintOptimizePtrCompare) {

           tty->print_cr("++++ Replaced: %d %s(%d,%d) --> %s", n->_idx, (n->Opcode() == Op_CmpP ? "CmpP" : "CmpN"), n->in(1)->_idx, n->in(2)->_idx, (res == _pcmp_eq ? "EQ" : "NotEQ"));

           if (Verbose) {

             n->dump(1);

           }

         }

 #endif

         _igvn->replace_node(n, res);

       }

     }

     // cleanup

     if (_pcmp_neq->outcnt() == 0)

       igvn->hash_delete(_pcmp_neq);

     if (_pcmp_eq->outcnt()  == 0)

       igvn->hash_delete(_pcmp_eq);

   }

 #ifndef PRODUCT

   if (PrintEscapeAnalysis) {

     dump(); // Dump ConnectionGraph

   }

 #endif

   bool has_scalar_replaceable_candidates = false;

   alloc_length = alloc_worklist.length();

   for (uint next = 0; next < alloc_length; ++next) {

     Node* n = alloc_worklist.at(next);

     PointsToNode* ptn = ptnode_adr(n->_idx);

     assert(ptn->escape_state() == PointsToNode::NoEscape, "sanity");

     if (ptn->scalar_replaceable()) {

       has_scalar_replaceable_candidates = true;

       break;

     }

   }

   if ( has_scalar_replaceable_candidates &&

        C->AliasLevel() >= 3 && EliminateAllocations ) {

     // Now use the escape information to create unique types for

     // scalar replaceable objects.

     split_unique_types(alloc_worklist);

     if (C->failing())  return false;

     C->print_method("After Escape Analysis", 2);

 #ifdef ASSERT

   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {

     tty->print("=== No allocations eliminated for ");

     C->method()->print_short_name();

     if(!EliminateAllocations) {

       tty->print(" since EliminateAllocations is off ===");

     } else if(!has_scalar_replaceable_candidates) {

       tty->print(" since there are no scalar replaceable candidates ===");

     } else if(C->AliasLevel() < 3) {

       tty->print(" since AliasLevel < 3 ===");

     }

     tty->cr();

 #endif

   }

   return has_non_escaping_obj;

 }

 // Find fields initializing values for allocations.

 void ConnectionGraph::find_init_values(Node* alloc, VectorSet* visited, PhaseTransform* phase) {

   assert(alloc->is_Allocate(), "Should be called for Allocate nodes only");

   PointsToNode* pta = ptnode_adr(alloc->_idx);

   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");

   InitializeNode* ini = alloc->as_Allocate()->initialization();

   Compile* C = _compile;

   visited->Reset();

   // Check if a oop field's initializing value is recorded and add

   // a corresponding NULL field's value if it is not recorded.

   // Connection Graph does not record a default initialization by NULL

   // captured by Initialize node.

   //

   uint ae_cnt = pta->edge_count();

   for (uint ei = 0; ei < ae_cnt; ei++) {

     uint nidx = pta->edge_target(ei); // Field (AddP)

     PointsToNode* ptn = ptnode_adr(nidx);

     assert(ptn->_node->is_AddP(), "Should be AddP nodes only");

     int offset = ptn->offset();

     if (offset != Type::OffsetBot &&

         offset != oopDesc::klass_offset_in_bytes() &&

         !visited->test_set(offset)) {

       // Check only oop fields.

       const Type* adr_type = ptn->_node->as_AddP()->bottom_type();

       BasicType basic_field_type = T_INT;

       if (adr_type->isa_instptr()) {

         ciField* field = C->alias_type(adr_type->isa_instptr())->field();

         if (field != NULL) {

           basic_field_type = field->layout_type();

         } else {

           // Ignore non field load (for example, klass load)

         }

       } else if (adr_type->isa_aryptr()) {

         if (offset != arrayOopDesc::length_offset_in_bytes()) {

           const Type* elemtype = adr_type->isa_aryptr()->elem();

           basic_field_type = elemtype->array_element_basic_type();

         } else {

           // Ignore array length load

         }

 #ifdef ASSERT

       } else {

         // Raw pointers are used for initializing stores so skip it

         // since it should be recorded already

         Node* base = get_addp_base(ptn->_node);

         assert(adr_type->isa_rawptr() && base->is_Proj() &&

                (base->in(0) == alloc),"unexpected pointer type");

 #endif

       }

       if (basic_field_type == T_OBJECT ||

           basic_field_type == T_NARROWOOP ||

           basic_field_type == T_ARRAY) {

         Node* value = NULL;

         if (ini != NULL) {

           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_OBJECT;

           Node* store = ini->find_captured_store(offset, type2aelembytes(ft), phase);

           if (store != NULL && store->is_Store()) {

             value = store->in(MemNode::ValueIn);

           } else if (ptn->edge_count() > 0) { // Are there oop stores?

             // Check for a store which follows allocation without branches.

             // For example, a volatile field store is not collected

             // by Initialize node. TODO: it would be nice to use idom() here.

             //

             // Search all references to the same field which use different

             // AddP nodes, for example, in the next case:

             //

             //    Point p[] = new Point[1];

             //    if ( x ) { p[0] = new Point(); p[0].x = x; }

             //    if ( p[0] != null ) { y = p[0].x; } // has CastPP

             //

             for (uint next = ei; (next < ae_cnt) && (value == NULL); next++) {

               uint fpi = pta->edge_target(next); // Field (AddP)

               PointsToNode *ptf = ptnode_adr(fpi);

               if (ptf->offset() == offset) {

                 Node* nf = ptf->_node;

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

                   store = nf->fast_out(i);

                   if (store->is_Store() && store->in(0) != NULL) {

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

                     while(!(ctrl == ini || ctrl == alloc || ctrl == NULL ||

                             ctrl == C->root() || ctrl == C->top() || ctrl->is_Region() ||

                             ctrl->is_IfTrue() || ctrl->is_IfFalse())) {

                        ctrl = ctrl->in(0);

                     }

                     if (ctrl == ini || ctrl == alloc) {

                       value = store->in(MemNode::ValueIn);

                       break;

                     }

                   }

                 }

               }

             }

           }

         }

         if (value == NULL || value != ptnode_adr(value->_idx)->_node) {

           // A field's initializing value was not recorded. Add NULL.

           uint null_idx = UseCompressedOops ? _noop_null : _oop_null;

           add_edge_from_fields(alloc->_idx, null_idx, offset);

         }

       }

     }

   }

 }

 // Adjust escape state after Connection Graph is built.

 void ConnectionGraph::adjust_escape_state(Node* n) {

   PointsToNode* ptn = ptnode_adr(n->_idx);

   assert(n->is_AddP(), "Should be called for AddP nodes only");

   // Search for objects which are not scalar replaceable

   // and mark them to propagate the state to referenced objects.

   //

   int offset = ptn->offset();

   Node* base = get_addp_base(n);

   VectorSet* ptset = PointsTo(base);

   int ptset_size = ptset->Size();

   // An object is not scalar replaceable if the field which may point

   // to it has unknown offset (unknown element of an array of objects).

   //

   if (offset == Type::OffsetBot) {

     uint e_cnt = ptn->edge_count();

     for (uint ei = 0; ei < e_cnt; ei++) {

       uint npi = ptn->edge_target(ei);

       ptnode_adr(npi)->set_scalar_replaceable(false);

     }

   }

   // Currently an object is not scalar replaceable if a LoadStore node

   // access its field since the field value is unknown after it.

   //

   bool has_LoadStore = false;

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

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

     if (use->is_LoadStore()) {

       has_LoadStore = true;

       break;

     }

   }

   // An object is not scalar replaceable if the address points

   // to unknown field (unknown element for arrays, offset is OffsetBot).

   //

   // Or the address may point to more then one object. This may produce

   // the false positive result (set not scalar replaceable)

   // since the flow-insensitive escape analysis can't separate

   // the case when stores overwrite the field's value from the case

   // when stores happened on different control branches.

   //

   // Note: it will disable scalar replacement in some cases:

   //

   //    Point p[] = new Point[1];

   //    p[0] = new Point(); // Will be not scalar replaced

   //

   // but it will save us from incorrect optimizations in next cases:

   //

   //    Point p[] = new Point[1];

   //    if ( x ) p[0] = new Point(); // Will be not scalar replaced

   //

   if (ptset_size > 1 || ptset_size != 0 &&

       (has_LoadStore || offset == Type::OffsetBot)) {

     for( VectorSetI j(ptset); j.test(); ++j ) {

       ptnode_adr(j.elem)->set_scalar_replaceable(false);

     }

   }

 }

 // Propagate escape states to referenced nodes.

 bool ConnectionGraph::propagate_escape_state(GrowableArray<int>* cg_worklist,

                                              GrowableArray<uint>* worklist,

                                              PointsToNode::EscapeState esc_state) {

   bool has_java_obj = false;

   // push all nodes with the same escape state on the worklist

   uint cg_length = cg_worklist->length();

   for (uint next = 0; next < cg_length; ++next) {

     int nk = cg_worklist->at(next);

     if (ptnode_adr(nk)->escape_state() == esc_state)

       worklist->push(nk);

   }

   // mark all reachable nodes

   while (worklist->length() > 0) {

     PointsToNode* ptn = ptnode_adr(worklist->pop());

     if (ptn->node_type() == PointsToNode::JavaObject) {

       has_java_obj = true;

     }

     uint e_cnt = ptn->edge_count();

     for (uint ei = 0; ei < e_cnt; ei++) {

       uint npi = ptn->edge_target(ei);

       PointsToNode *np = ptnode_adr(npi);

       if (np->escape_state() < esc_state) {

         set_escape_state(npi, esc_state);

         worklist->push(npi);

       }

     }

   }

   // Has not escaping java objects

   return has_java_obj && (esc_state < PointsToNode::GlobalEscape);

 }

 // Optimize objects compare.

 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {

   assert(OptimizePtrCompare, "sanity");

   // Clone returned Set since PointsTo() returns pointer

   // to the same structure ConnectionGraph.pt_ptset.

   VectorSet ptset1 = *PointsTo(n->in(1));

   VectorSet ptset2 = *PointsTo(n->in(2));

   // Check simple cases first.

   if (ptset1.Size() == 1) {

     uint pt1 = ptset1.getelem();

     PointsToNode* ptn1 = ptnode_adr(pt1);

     if (ptn1->escape_state() == PointsToNode::NoEscape) {

       if (ptset2.Size() == 1 && ptset2.getelem() == pt1) {

         // Comparing the same not escaping object.

         return _pcmp_eq;

       }

       Node* obj = ptn1->_node;

       // Comparing not escaping allocation.

       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&

           !ptset2.test(pt1)) {

         return _pcmp_neq; // This includes nullness check.

       }

     }

   } else if (ptset2.Size() == 1) {

     uint pt2 = ptset2.getelem();

     PointsToNode* ptn2 = ptnode_adr(pt2);

     if (ptn2->escape_state() == PointsToNode::NoEscape) {

       Node* obj = ptn2->_node;

       // Comparing not escaping allocation.

       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&

           !ptset1.test(pt2)) {

         return _pcmp_neq; // This includes nullness check.

       }

     }

   }

   if (!ptset1.disjoint(ptset2)) {

     return NULL; // Sets are not disjoint

   }

   // Sets are disjoint.

   bool set1_has_unknown_ptr = ptset1.test(_phantom_object) != 0;

   bool set2_has_unknown_ptr = ptset2.test(_phantom_object) != 0;

   bool set1_has_null_ptr   = (ptset1.test(_oop_null) | ptset1.test(_noop_null)) != 0;

   bool set2_has_null_ptr   = (ptset2.test(_oop_null) | ptset2.test(_noop_null)) != 0;

   if (set1_has_unknown_ptr && set2_has_null_ptr ||

       set2_has_unknown_ptr && set1_has_null_ptr) {

     // Check nullness of unknown object.

     return NULL;

   }

   // Disjointness by itself is not sufficient since

   // alias analysis is not complete for escaped objects.

   // Disjoint sets are definitely unrelated only when

   // at least one set has only not escaping objects.

   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {

     bool has_only_non_escaping_alloc = true;

     for (VectorSetI i(&ptset1); i.test(); ++i) {

       uint pt = i.elem;

       PointsToNode* ptn = ptnode_adr(pt);

       Node* obj = ptn->_node;

       if (ptn->escape_state() != PointsToNode::NoEscape ||

           !(obj->is_Allocate() || obj->is_CallStaticJava())) {

         has_only_non_escaping_alloc = false;

         break;

       }

     }

     if (has_only_non_escaping_alloc) {

       return _pcmp_neq;

     }

   }

   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {

     bool has_only_non_escaping_alloc = true;

     for (VectorSetI i(&ptset2); i.test(); ++i) {

       uint pt = i.elem;

       PointsToNode* ptn = ptnode_adr(pt);

       Node* obj = ptn->_node;

       if (ptn->escape_state() != PointsToNode::NoEscape ||

           !(obj->is_Allocate() || obj->is_CallStaticJava())) {

         has_only_non_escaping_alloc = false;

         break;

       }

     }

     if (has_only_non_escaping_alloc) {

       return _pcmp_neq;

     }

   }

   return NULL;

 }

 void ConnectionGraph::process_call_arguments(CallNode *call, PhaseTransform *phase) {

     switch (call->Opcode()) {

 #ifdef ASSERT

     case Op_Allocate:

     case Op_AllocateArray:

     case Op_Lock:

     case Op_Unlock:

       assert(false, "should be done already");

       break;

 #endif

     case Op_CallLeaf:

     case Op_CallLeafNoFP:

     {

       // Stub calls, objects do not escape but they are not scale replaceable.

       // Adjust escape state for outgoing arguments.

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

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

         const Type* at = d->field_at(i);

         Node *arg = call->in(i)->uncast();

         const Type *aat = phase->type(arg);

         if (!arg->is_top() && at->isa_ptr() && aat->isa_ptr() &&

             ptnode_adr(arg->_idx)->escape_state() < PointsToNode::ArgEscape) {

           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||

                  aat->isa_ptr() != NULL, "expecting an Ptr");

 #ifdef ASSERT

           if (!(call->Opcode() == Op_CallLeafNoFP &&

                 call->as_CallLeaf()->_name != NULL &&

                 (strstr(call->as_CallLeaf()->_name, "arraycopy")  != 0) ||

                 call->as_CallLeaf()->_name != NULL &&

                 (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||

                  strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ))

           ) {

             call->dump();

             assert(false, "EA: unexpected CallLeaf");

           }

 #endif

           set_escape_state(arg->_idx, PointsToNode::ArgEscape);

           if (arg->is_AddP()) {

             //

             // The inline_native_clone() case when the arraycopy stub is called

             // after the allocation before Initialize and CheckCastPP nodes.

             //

             // Set AddP's base (Allocate) as not scalar replaceable since

             // pointer to the base (with offset) is passed as argument.

             //

             arg = get_addp_base(arg);

           }

           for( VectorSetI j(PointsTo(arg)); j.test(); ++j ) {

             uint pt = j.elem;

             set_escape_state(pt, PointsToNode::ArgEscape);

           }

         }

       }

       break;

     }

     case Op_CallStaticJava:

     // For a static call, we know exactly what method is being called.

     // Use bytecode estimator to record the call's escape affects

     {

       ciMethod *meth = call->as_CallJava()->method();

       BCEscapeAnalyzer *call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;

       // fall-through if not a Java method or no analyzer information

       if (call_analyzer != NULL) {

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

         bool copy_dependencies = false;

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

           const Type* at = d->field_at(i);

           int k = i - TypeFunc::Parms;

           Node *arg = call->in(i)->uncast();

           if (at->isa_oopptr() != NULL &&

               ptnode_adr(arg->_idx)->escape_state() < PointsToNode::GlobalEscape) {

             bool global_escapes = false;

             bool fields_escapes = false;

             if (!call_analyzer->is_arg_stack(k)) {

               // The argument global escapes, mark everything it could point to

               set_escape_state(arg->_idx, PointsToNode::GlobalEscape);

               global_escapes = true;

             } else {

               if (!call_analyzer->is_arg_local(k)) {

                 // The argument itself doesn't escape, but any fields might

                 fields_escapes = true;

               }

               set_escape_state(arg->_idx, PointsToNode::ArgEscape);

               copy_dependencies = true;

             }

             for( VectorSetI j(PointsTo(arg)); j.test(); ++j ) {

               uint pt = j.elem;

               if (global_escapes) {

                 //The argument global escapes, mark everything it could point to

                 set_escape_state(pt, PointsToNode::GlobalEscape);

               } else {

                 if (fields_escapes) {

                   // The argument itself doesn't escape, but any fields might

                   add_edge_from_fields(pt, _phantom_object, Type::OffsetBot);

                 }

                 set_escape_state(pt, PointsToNode::ArgEscape);

               }

             }

           }

         }

         if (copy_dependencies)

           call_analyzer->copy_dependencies(_compile->dependencies());

         break;

       }

     }

     default:

     // Fall-through here if not a Java method or no analyzer information

     // or some other type of call, assume the worst case: all arguments

     // globally escape.

     {

       // adjust escape state for  outgoing arguments

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

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

         const Type* at = d->field_at(i);

         if (at->isa_oopptr() != NULL) {

           Node *arg = call->in(i)->uncast();

           set_escape_state(arg->_idx, PointsToNode::GlobalEscape);

           for( VectorSetI j(PointsTo(arg)); j.test(); ++j ) {

             uint pt = j.elem;

             set_escape_state(pt, PointsToNode::GlobalEscape);

           }

         }

       }

     }

   }

 }

 void ConnectionGraph::process_call_result(ProjNode *resproj, PhaseTransform *phase) {

   CallNode   *call = resproj->in(0)->as_Call();

   uint    call_idx = call->_idx;

   uint resproj_idx = resproj->_idx;

   switch (call->Opcode()) {

     case Op_Allocate:

     {

       Node *k = call->in(AllocateNode::KlassNode);

       const TypeKlassPtr *kt = k->bottom_type()->isa_klassptr();

       assert(kt != NULL, "TypeKlassPtr  required.");

       ciKlass* cik = kt->klass();

       PointsToNode::EscapeState es;

       uint edge_to;

       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||

          !cik->is_instance_klass() || // StressReflectiveCode

           cik->as_instance_klass()->has_finalizer()) {

         es = PointsToNode::GlobalEscape;

         edge_to = _phantom_object; // Could not be worse

       } else {

         es = PointsToNode::NoEscape;

         edge_to = call_idx;

         assert(ptnode_adr(call_idx)->scalar_replaceable(), "sanity");

       }

       set_escape_state(call_idx, es);

       add_pointsto_edge(resproj_idx, edge_to);

       _processed.set(resproj_idx);

       break;

     }

     case Op_AllocateArray:

     {

       Node *k = call->in(AllocateNode::KlassNode);

       const TypeKlassPtr *kt = k->bottom_type()->isa_klassptr();

       assert(kt != NULL, "TypeKlassPtr  required.");

       ciKlass* cik = kt->klass();

       PointsToNode::EscapeState es;

       uint edge_to;

       if (!cik->is_array_klass()) { // StressReflectiveCode

         es = PointsToNode::GlobalEscape;

         edge_to = _phantom_object;

       } else {

         es = PointsToNode::NoEscape;

         edge_to = call_idx;

         assert(ptnode_adr(call_idx)->scalar_replaceable(), "sanity");

         int length = call->in(AllocateNode::ALength)->find_int_con(-1);

         if (length < 0 || length > EliminateAllocationArraySizeLimit) {

           // Not scalar replaceable if the length is not constant or too big.

           ptnode_adr(call_idx)->set_scalar_replaceable(false);

         }

       }

       set_escape_state(call_idx, es);

       add_pointsto_edge(resproj_idx, edge_to);

       _processed.set(resproj_idx);

       break;

     }

     case Op_CallStaticJava:

     // For a static call, we know exactly what method is being called.

     // Use bytecode estimator to record whether the call's return value escapes

     {

       bool done = true;

       const TypeTuple *r = call->tf()->range();

       const Type* ret_type = NULL;

       if (r->cnt() > TypeFunc::Parms)

         ret_type = r->field_at(TypeFunc::Parms);

       // Note:  we use isa_ptr() instead of isa_oopptr()  here because the

       //        _multianewarray functions return a TypeRawPtr.

       if (ret_type == NULL || ret_type->isa_ptr() == NULL) {

         _processed.set(resproj_idx);

         break;  // doesn't return a pointer type

       }

       ciMethod *meth = call->as_CallJava()->method();

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

       if (meth == NULL) {

         // not a Java method, assume global escape

         set_escape_state(call_idx, PointsToNode::GlobalEscape);

         add_pointsto_edge(resproj_idx, _phantom_object);

       } else {

         BCEscapeAnalyzer *call_analyzer = meth->get_bcea();

         bool copy_dependencies = false;

         if (call_analyzer->is_return_allocated()) {

           // Returns a newly allocated unescaped object, simply

           // update dependency information.

           // Mark it as NoEscape so that objects referenced by

           // it's fields will be marked as NoEscape at least.

           set_escape_state(call_idx, PointsToNode::NoEscape);

           ptnode_adr(call_idx)->set_scalar_replaceable(false);

           add_pointsto_edge(resproj_idx, call_idx);

           copy_dependencies = true;

         } else if (call_analyzer->is_return_local()) {

           // determine whether any arguments are returned

           set_escape_state(call_idx, PointsToNode::ArgEscape);

           bool ret_arg = false;

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

             const Type* at = d->field_at(i);

             if (at->isa_oopptr() != NULL) {

               Node *arg = call->in(i)->uncast();

               if (call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {

                 ret_arg = true;

                 PointsToNode *arg_esp = ptnode_adr(arg->_idx);

                 if (arg_esp->node_type() == PointsToNode::UnknownType)

                   done = false;

                 else if (arg_esp->node_type() == PointsToNode::JavaObject)

                   add_pointsto_edge(resproj_idx, arg->_idx);

                 else

                   add_deferred_edge(resproj_idx, arg->_idx);

               }

             }

           }

           if (done && !ret_arg) {

             // Returns unknown object.

             set_escape_state(call_idx, PointsToNode::GlobalEscape);

             add_pointsto_edge(resproj_idx, _phantom_object);

           }

           if (done) {

             copy_dependencies = true;

           }

         } else {

           set_escape_state(call_idx, PointsToNode::GlobalEscape);

           add_pointsto_edge(resproj_idx, _phantom_object);

         }

         if (copy_dependencies)

           call_analyzer->copy_dependencies(_compile->dependencies());

       }

       if (done)

         _processed.set(resproj_idx);

       break;

     }

     default:

     // Some other type of call, assume the worst case that the

     // returned value, if any, globally escapes.

     {

       const TypeTuple *r = call->tf()->range();

       if (r->cnt() > TypeFunc::Parms) {

         const Type* ret_type = r->field_at(TypeFunc::Parms);

         // Note:  we use isa_ptr() instead of isa_oopptr()  here because the

         //        _multianewarray functions return a TypeRawPtr.

         if (ret_type->isa_ptr() != NULL) {

           set_escape_state(call_idx, PointsToNode::GlobalEscape);

           add_pointsto_edge(resproj_idx, _phantom_object);

         }

       }

       _processed.set(resproj_idx);

     }

   }

 }

 // Populate Connection Graph with Ideal nodes and create simple

 // connection graph edges (do not need to check the node_type of inputs

 // or to call PointsTo() to walk the connection graph).

 void ConnectionGraph::record_for_escape_analysis(Node *n, PhaseTransform *phase) {

   if (_processed.test(n->_idx))

     return; // No need to redefine node's state.

   if (n->is_Call()) {

     // Arguments to allocation and locking don't escape.

     if (n->is_Allocate()) {

       add_node(n, PointsToNode::JavaObject, PointsToNode::UnknownEscape, true);

       record_for_optimizer(n);

     } else if (n->is_Lock() || n->is_Unlock()) {

       // Put Lock and Unlock nodes on IGVN worklist to process them during

       // the first IGVN optimization when escape information is still available.

       record_for_optimizer(n);

       _processed.set(n->_idx);

     } else {

       // Don't mark as processed since call's arguments have to be processed.

       PointsToNode::NodeType nt = PointsToNode::UnknownType;

       PointsToNode::EscapeState es = PointsToNode::UnknownEscape;

       // Check if a call returns an object.

       const TypeTuple *r = n->as_Call()->tf()->range();

       if (r->cnt() > TypeFunc::Parms &&

           r->field_at(TypeFunc::Parms)->isa_ptr() &&

           n->as_Call()->proj_out(TypeFunc::Parms) != NULL) {

         nt = PointsToNode::JavaObject;

         if (!n->is_CallStaticJava()) {

           // Since the called mathod is statically unknown assume

           // the worst case that the returned value globally escapes.

           es = PointsToNode::GlobalEscape;

         }

       }

       add_node(n, nt, es, false);

     }

     return;

   }

   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because

   // ThreadLocal has RawPrt type.

   switch (n->Opcode()) {

     case Op_AddP:

     {

       add_node(n, PointsToNode::Field, PointsToNode::UnknownEscape, false);

       break;

     }

     case Op_CastX2P:

     { // "Unsafe" memory access.

       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);

       break;

     }

     case Op_CastPP:

     case Op_CheckCastPP:

     case Op_EncodeP:

     case Op_DecodeN:

     {

       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);

       int ti = n->in(1)->_idx;

       PointsToNode::NodeType nt = ptnode_adr(ti)->node_type();

       if (nt == PointsToNode::UnknownType) {

         _delayed_worklist.push(n); // Process it later.

         break;

       } else if (nt == PointsToNode::JavaObject) {

         add_pointsto_edge(n->_idx, ti);

       } else {

         add_deferred_edge(n->_idx, ti);

       }

       _processed.set(n->_idx);

       break;

     }

     case Op_ConP:

     {

       // assume all pointer constants globally escape except for null

       PointsToNode::EscapeState es;

       if (phase->type(n) == TypePtr::NULL_PTR)

         es = PointsToNode::NoEscape;

       else

         es = PointsToNode::GlobalEscape;

       add_node(n, PointsToNode::JavaObject, es, true);

       break;

     }

     case Op_ConN:

     {

       // assume all narrow oop constants globally escape except for null

       PointsToNode::EscapeState es;

       if (phase->type(n) == TypeNarrowOop::NULL_PTR)

         es = PointsToNode::NoEscape;

       else

         es = PointsToNode::GlobalEscape;

       add_node(n, PointsToNode::JavaObject, es, true);

       break;

     }

     case Op_CreateEx:

     {

       // assume that all exception objects globally escape

       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);

       break;

     }

     case Op_LoadKlass:

     case Op_LoadNKlass:

     {

       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);

       break;

     }

     case Op_LoadP:

     case Op_LoadN:

     {

       const Type *t = phase->type(n);

       if (t->make_ptr() == NULL) {

         _processed.set(n->_idx);

         return;

       }

       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);

       break;

     }

     case Op_Parm:

     {

       _processed.set(n->_idx); // No need to redefine it state.

       uint con = n->as_Proj()->_con;

       if (con < TypeFunc::Parms)

         return;

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

       if (t->isa_ptr() == NULL)

         return;

       // We have to assume all input parameters globally escape

       // (Note: passing 'false' since _processed is already set).

       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, false);

       break;

     }

     case Op_PartialSubtypeCheck:

     { // Produces Null or notNull and is used in CmpP.

       add_node(n, PointsToNode::JavaObject, PointsToNode::ArgEscape, true);

       break;

     }

     case Op_Phi:

     {

       const Type *t = n->as_Phi()->type();

       if (t->make_ptr() == NULL) {

         // nothing to do if not an oop or narrow oop

         _processed.set(n->_idx);

         return;

       }

       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);

       uint i;

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

         Node* in = n->in(i);

         if (in == NULL)

           continue;  // ignore NULL

         in = in->uncast();

         if (in->is_top() || in == n)

           continue;  // ignore top or inputs which go back this node

         int ti = in->_idx;

         PointsToNode::NodeType nt = ptnode_adr(ti)->node_type();

         if (nt == PointsToNode::UnknownType) {

           break;

         } else if (nt == PointsToNode::JavaObject) {

           add_pointsto_edge(n->_idx, ti);

         } else {

           add_deferred_edge(n->_idx, ti);

         }

       }

       if (i >= n->req())

         _processed.set(n->_idx);

       else

         _delayed_worklist.push(n);

       break;

     }

     case Op_Proj:

     {

       // we are only interested in the oop result projection from a call

       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() ) {

         const TypeTuple *r = n->in(0)->as_Call()->tf()->range();

         assert(r->cnt() > TypeFunc::Parms, "sanity");

         if (r->field_at(TypeFunc::Parms)->isa_ptr() != NULL) {

           add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);

           int ti = n->in(0)->_idx;

           // The call may not be registered yet (since not all its inputs are registered)

           // if this is the projection from backbranch edge of Phi.

           if (ptnode_adr(ti)->node_type() != PointsToNode::UnknownType) {

             process_call_result(n->as_Proj(), phase);

           }

           if (!_processed.test(n->_idx)) {

             // The call's result may need to be processed later if the call

             // returns it's argument and the argument is not processed yet.

             _delayed_worklist.push(n);

           }

           break;

         }

       }

       _processed.set(n->_idx);

       break;

     }

     case Op_Return:

     {

       if( n->req() > TypeFunc::Parms &&

           phase->type(n->in(TypeFunc::Parms))->isa_oopptr() ) {

         // Treat Return value as LocalVar with GlobalEscape escape state.

         add_node(n, PointsToNode::LocalVar, PointsToNode::GlobalEscape, false);