       1 /*
       2  * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
       3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       4  *
       5  * This code is free software; you can redistribute it and/or modify it
       6  * under the terms of the GNU General Public License version 2 only, as
       7  * published by the Free Software Foundation.
       8  *
       9  * This code is distributed in the hope that it will be useful, but WITHOUT
      10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      12  * version 2 for more details (a copy is included in the LICENSE file that
      13  * accompanied this code).
      14  *
      15  * You should have received a copy of the GNU General Public License version
      16  * 2 along with this work; if not, write to the Free Software Foundation,
      17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
      18  *
      19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
      20  * or visit www.oracle.com if you need additional information or have any
      21  * questions.
      22  *
      23  */
      24
      25 #include "precompiled.hpp"
      26 #include "ci/bcEscapeAnalyzer.hpp"
      27 #include "compiler/compileLog.hpp"
      28 #include "libadt/vectset.hpp"
      29 #include "memory/allocation.hpp"
      30 #include "opto/c2compiler.hpp"
      31 #include "opto/callnode.hpp"
      32 #include "opto/cfgnode.hpp"
      33 #include "opto/compile.hpp"
      34 #include "opto/escape.hpp"
      35 #include "opto/phaseX.hpp"
      36 #include "opto/movenode.hpp"
      37 #include "opto/rootnode.hpp"
      38
      39 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
      40   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
      41   _in_worklist(C->comp_arena()),
      42   _next_pidx(0),
      43   _collecting(true),
      44   _verify(false),
      45   _compile(C),
      46   _igvn(igvn),
      47   _node_map(C->comp_arena()) {
      48   // Add unknown java object.
      49   add_java_object(C->top(), PointsToNode::GlobalEscape);
      50   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
      51   // Add ConP(#NULL) and ConN(#NULL) nodes.
      52   Node* oop_null = igvn->zerocon(T_OBJECT);
      53   assert(oop_null->_idx < nodes_size(), "should be created already");
      54   add_java_object(oop_null, PointsToNode::NoEscape);
      55   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
      56   if (UseCompressedOops) {
      57     Node* noop_null = igvn->zerocon(T_NARROWOOP);
      58     assert(noop_null->_idx < nodes_size(), "should be created already");
      59     map_ideal_node(noop_null, null_obj);
      60   }
      61   _pcmp_neq = NULL; // Should be initialized
      62   _pcmp_eq  = NULL;
      63 }
      64
      65 bool ConnectionGraph::has_candidates(Compile *C) {
      66   // EA brings benefits only when the code has allocations and/or locks which
      67   // are represented by ideal Macro nodes.
      68   int cnt = C->macro_count();
      69   for (int i = 0; i < cnt; i++) {
      70     Node *n = C->macro_node(i);
      71     if (n->is_Allocate())
      72       return true;
      73     if (n->is_Lock()) {
      74       Node* obj = n->as_Lock()->obj_node()->uncast();
      75       if (!(obj->is_Parm() || obj->is_Con()))
      76         return true;
      77     }
      78     if (n->is_CallStaticJava() &&
      79         n->as_CallStaticJava()->is_boxing_method()) {
      80       return true;
      81     }
      82   }
      83   return false;
      84 }
      85
      86 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
      87   Compile::TracePhase tp("escapeAnalysis", &Phase::timers[Phase::_t_escapeAnalysis]);
      88   ResourceMark rm;
      89
      90   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
      91   // to create space for them in ConnectionGraph::_nodes[].
      92   Node* oop_null = igvn->zerocon(T_OBJECT);
      93   Node* noop_null = igvn->zerocon(T_NARROWOOP);
      94   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
      95   // Perform escape analysis
      96   if (congraph->compute_escape()) {
      97     // There are non escaping objects.
      98     C->set_congraph(congraph);
      99   }
     100   // Cleanup.
     101   if (oop_null->outcnt() == 0)
     102     igvn->hash_delete(oop_null);
     103   if (noop_null->outcnt() == 0)
     104     igvn->hash_delete(noop_null);
     105 }
     106
     107 bool ConnectionGraph::compute_escape() {
     108   Compile* C = _compile;
     109   PhaseGVN* igvn = _igvn;
     110
     111   // Worklists used by EA.
     112   Unique_Node_List delayed_worklist;
     113   GrowableArray<Node*> alloc_worklist;
     114   GrowableArray<Node*> ptr_cmp_worklist;
     115   GrowableArray<Node*> storestore_worklist;
     116   GrowableArray<PointsToNode*>   ptnodes_worklist;
     117   GrowableArray<JavaObjectNode*> java_objects_worklist;
     118   GrowableArray<JavaObjectNode*> non_escaped_worklist;
     119   GrowableArray<FieldNode*>      oop_fields_worklist;
     120   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
     121
     122   { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
     123
     124   // 1. Populate Connection Graph (CG) with PointsTo nodes.
     125   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
     126   // Initialize worklist
     127   if (C->root() != NULL) {
     128     ideal_nodes.push(C->root());
     129   }
     130   // Processed ideal nodes are unique on ideal_nodes list
     131   // but several ideal nodes are mapped to the phantom_obj.
     132   // To avoid duplicated entries on the following worklists
     133   // add the phantom_obj only once to them.
     134   ptnodes_worklist.append(phantom_obj);
     135   java_objects_worklist.append(phantom_obj);
     136   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
     137     Node* n = ideal_nodes.at(next);
     138     // Create PointsTo nodes and add them to Connection Graph. Called
     139     // only once per ideal node since ideal_nodes is Unique_Node list.
     140     add_node_to_connection_graph(n, &delayed_worklist);
     141     PointsToNode* ptn = ptnode_adr(n->_idx);
     142     if (ptn != NULL && ptn != phantom_obj) {
     143       ptnodes_worklist.append(ptn);
     144       if (ptn->is_JavaObject()) {
     145         java_objects_worklist.append(ptn->as_JavaObject());
     146         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
     147             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
     148           // Only allocations and java static calls results are interesting.
     149           non_escaped_worklist.append(ptn->as_JavaObject());
     150         }
     151       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
     152         oop_fields_worklist.append(ptn->as_Field());
     153       }
     154     }
     155     if (n->is_MergeMem()) {
     156       // Collect all MergeMem nodes to add memory slices for
     157       // scalar replaceable objects in split_unique_types().
     158       _mergemem_worklist.append(n->as_MergeMem());
     159     } else if (OptimizePtrCompare && n->is_Cmp() &&
     160                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
     161       // Collect compare pointers nodes.
     162       ptr_cmp_worklist.append(n);
     163     } else if (n->is_MemBarStoreStore()) {
     164       // Collect all MemBarStoreStore nodes so that depending on the
     165       // escape status of the associated Allocate node some of them
     166       // may be eliminated.
     167       storestore_worklist.append(n);
     168     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
     169                (n->req() > MemBarNode::Precedent)) {
     170       record_for_optimizer(n);
     171 #ifdef ASSERT
     172     } else if (n->is_AddP()) {
     173       // Collect address nodes for graph verification.
     174       addp_worklist.append(n);
     175 #endif
     176     }
     177     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
     178       Node* m = n->fast_out(i);   // Get user
     179       ideal_nodes.push(m);
     180     }
     181   }
     182   if (non_escaped_worklist.length() == 0) {
     183     _collecting = false;
     184     return false; // Nothing to do.
     185   }
     186   // Add final simple edges to graph.
     187   while(delayed_worklist.size() > 0) {
     188     Node* n = delayed_worklist.pop();
     189     add_final_edges(n);
     190   }
     191   int ptnodes_length = ptnodes_worklist.length();
     192
     193 #ifdef ASSERT
     194   if (VerifyConnectionGraph) {
     195     // Verify that no new simple edges could be created and all
     196     // local vars has edges.
     197     _verify = true;
     198     for (int next = 0; next < ptnodes_length; ++next) {
     199       PointsToNode* ptn = ptnodes_worklist.at(next);
     200       add_final_edges(ptn->ideal_node());
     201       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
     202         ptn->dump();
     203         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
     204       }
     205     }
     206     _verify = false;
     207   }
     208 #endif
     209   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
     210   // processing, calls to CI to resolve symbols (types, fields, methods)
     211   // referenced in bytecode. During symbol resolution VM may throw
     212   // an exception which CI cleans and converts to compilation failure.
     213   if (C->failing())  return false;
     214
     215   // 2. Finish Graph construction by propagating references to all
     216   //    java objects through graph.
     217   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
     218                                  java_objects_worklist, oop_fields_worklist)) {
     219     // All objects escaped or hit time or iterations limits.
     220     _collecting = false;
     221     return false;
     222   }
     223
     224   // 3. Adjust scalar_replaceable state of nonescaping objects and push
     225   //    scalar replaceable allocations on alloc_worklist for processing
     226   //    in split_unique_types().
     227   int non_escaped_length = non_escaped_worklist.length();
     228   for (int next = 0; next < non_escaped_length; next++) {
     229     JavaObjectNode* ptn = non_escaped_worklist.at(next);
     230     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
     231     Node* n = ptn->ideal_node();
     232     if (n->is_Allocate()) {
     233       n->as_Allocate()->_is_non_escaping = noescape;
     234     }
     235     if (n->is_CallStaticJava()) {
     236       n->as_CallStaticJava()->_is_non_escaping = noescape;
     237     }
     238     if (noescape && ptn->scalar_replaceable()) {
     239       adjust_scalar_replaceable_state(ptn);
     240       if (ptn->scalar_replaceable()) {
     241         alloc_worklist.append(ptn->ideal_node());
     242       }
     243     }
     244   }
     245
     246 #ifdef ASSERT
     247   if (VerifyConnectionGraph) {
     248     // Verify that graph is complete - no new edges could be added or needed.
     249     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
     250                             java_objects_worklist, addp_worklist);
     251   }
     252   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
     253   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
     254          null_obj->edge_count() == 0 &&
     255          !null_obj->arraycopy_src() &&
     256          !null_obj->arraycopy_dst(), "sanity");
     257 #endif
     258
     259   _collecting = false;
     260
     261   } // TracePhase t3("connectionGraph")
     262
     263   // 4. Optimize ideal graph based on EA information.
     264   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
     265   if (has_non_escaping_obj) {
     266     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
     267   }
     268
     269 #ifndef PRODUCT
     270   if (PrintEscapeAnalysis) {
     271     dump(ptnodes_worklist); // Dump ConnectionGraph
     272   }
     273 #endif
     274
     275   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
     276 #ifdef ASSERT
     277   if (VerifyConnectionGraph) {
     278     int alloc_length = alloc_worklist.length();
     279     for (int next = 0; next < alloc_length; ++next) {
     280       Node* n = alloc_worklist.at(next);
     281       PointsToNode* ptn = ptnode_adr(n->_idx);
     282       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
     283     }
     284   }
     285 #endif
     286
     287   // 5. Separate memory graph for scalar replaceable allcations.
     288   if (has_scalar_replaceable_candidates &&
     289       C->AliasLevel() >= 3 && EliminateAllocations) {
     290     // Now use the escape information to create unique types for
     291     // scalar replaceable objects.
     292     split_unique_types(alloc_worklist);
     293     if (C->failing())  return false;
     294     C->print_method(PHASE_AFTER_EA, 2);
     295
     296 #ifdef ASSERT
     297   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
     298     tty->print("=== No allocations eliminated for ");
     299     C->method()->print_short_name();
     300     if(!EliminateAllocations) {
     301       tty->print(" since EliminateAllocations is off ===");
     302     } else if(!has_scalar_replaceable_candidates) {
     303       tty->print(" since there are no scalar replaceable candidates ===");
     304     } else if(C->AliasLevel() < 3) {
     305       tty->print(" since AliasLevel < 3 ===");
     306     }
     307     tty->cr();
     308 #endif
     309   }
     310   return has_non_escaping_obj;
     311 }
     312
     313 // Utility function for nodes that load an object
     314 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
     315   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
     316   // ThreadLocal has RawPtr type.
     317   const Type* t = _igvn->type(n);
     318   if (t->make_ptr() != NULL) {
     319     Node* adr = n->in(MemNode::Address);
     320 #ifdef ASSERT
     321     if (!adr->is_AddP()) {
     322       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
     323     } else {
     324       assert((ptnode_adr(adr->_idx) == NULL ||
     325               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
     326     }
     327 #endif
     328     add_local_var_and_edge(n, PointsToNode::NoEscape,
     329                            adr, delayed_worklist);
     330   }
     331 }
     332
     333 // Populate Connection Graph with PointsTo nodes and create simple
     334 // connection graph edges.
     335 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
     336   assert(!_verify, "this method sould not be called for verification");
     337   PhaseGVN* igvn = _igvn;
     338   uint n_idx = n->_idx;
     339   PointsToNode* n_ptn = ptnode_adr(n_idx);
     340   if (n_ptn != NULL)
     341     return; // No need to redefine PointsTo node during first iteration.
     342
     343   if (n->is_Call()) {
     344     // Arguments to allocation and locking don't escape.
     345     if (n->is_AbstractLock()) {
     346       // Put Lock and Unlock nodes on IGVN worklist to process them during
     347       // first IGVN optimization when escape information is still available.
     348       record_for_optimizer(n);
     349     } else if (n->is_Allocate()) {
     350       add_call_node(n->as_Call());
     351       record_for_optimizer(n);
     352     } else {
     353       if (n->is_CallStaticJava()) {
     354         const char* name = n->as_CallStaticJava()->_name;
     355         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
     356           return; // Skip uncommon traps
     357       }
     358       // Don't mark as processed since call's arguments have to be processed.
     359       delayed_worklist->push(n);
     360       // Check if a call returns an object.
     361       if ((n->as_Call()->returns_pointer() &&
     362            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
     363           (n->is_CallStaticJava() &&
     364            n->as_CallStaticJava()->is_boxing_method())) {
     365         add_call_node(n->as_Call());
     366       }
     367     }
     368     return;
     369   }
     370   // Put this check here to process call arguments since some call nodes
     371   // point to phantom_obj.
     372   if (n_ptn == phantom_obj || n_ptn == null_obj)
     373     return; // Skip predefined nodes.
     374
     375   int opcode = n->Opcode();
     376   switch (opcode) {
     377     case Op_AddP: {
     378       Node* base = get_addp_base(n);
     379       PointsToNode* ptn_base = ptnode_adr(base->_idx);
     380       // Field nodes are created for all field types. They are used in
     381       // adjust_scalar_replaceable_state() and split_unique_types().
     382       // Note, non-oop fields will have only base edges in Connection
     383       // Graph because such fields are not used for oop loads and stores.
     384       int offset = address_offset(n, igvn);
     385       add_field(n, PointsToNode::NoEscape, offset);
     386       if (ptn_base == NULL) {
     387         delayed_worklist->push(n); // Process it later.
     388       } else {
     389         n_ptn = ptnode_adr(n_idx);
     390         add_base(n_ptn->as_Field(), ptn_base);
     391       }
     392       break;
     393     }
     394     case Op_CastX2P: {
     395       map_ideal_node(n, phantom_obj);
     396       break;
     397     }
     398     case Op_CastPP:
     399     case Op_CheckCastPP:
     400     case Op_EncodeP:
     401     case Op_DecodeN:
     402     case Op_EncodePKlass:
     403     case Op_DecodeNKlass: {
     404       add_local_var_and_edge(n, PointsToNode::NoEscape,
     405                              n->in(1), delayed_worklist);
     406       break;
     407     }
     408     case Op_CMoveP: {
     409       add_local_var(n, PointsToNode::NoEscape);
     410       // Do not add edges during first iteration because some could be
     411       // not defined yet.
     412       delayed_worklist->push(n);
     413       break;
     414     }
     415     case Op_ConP:
     416     case Op_ConN:
     417     case Op_ConNKlass: {
     418       // assume all oop constants globally escape except for null
     419       PointsToNode::EscapeState es;
     420       const Type* t = igvn->type(n);
     421       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
     422         es = PointsToNode::NoEscape;
     423       } else {
     424         es = PointsToNode::GlobalEscape;
     425       }
     426       add_java_object(n, es);
     427       break;
     428     }
     429     case Op_CreateEx: {
     430       // assume that all exception objects globally escape
     431       map_ideal_node(n, phantom_obj);
     432       break;
     433     }
     434     case Op_LoadKlass:
     435     case Op_LoadNKlass: {
     436       // Unknown class is loaded
     437       map_ideal_node(n, phantom_obj);
     438       break;
     439     }
     440     case Op_LoadP:
     441     case Op_LoadN:
     442     case Op_LoadPLocked: {
     443       add_objload_to_connection_graph(n, delayed_worklist);
     444       break;
     445     }
     446     case Op_Parm: {
     447       map_ideal_node(n, phantom_obj);
     448       break;
     449     }
     450     case Op_PartialSubtypeCheck: {
     451       // Produces Null or notNull and is used in only in CmpP so
     452       // phantom_obj could be used.
     453       map_ideal_node(n, phantom_obj); // Result is unknown
     454       break;
     455     }
     456     case Op_Phi: {
     457       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
     458       // ThreadLocal has RawPtr type.
     459       const Type* t = n->as_Phi()->type();
     460       if (t->make_ptr() != NULL) {
     461         add_local_var(n, PointsToNode::NoEscape);
     462         // Do not add edges during first iteration because some could be
     463         // not defined yet.
     464         delayed_worklist->push(n);
     465       }
     466       break;
     467     }
     468     case Op_Proj: {
     469       // we are only interested in the oop result projection from a call
     470       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
     471           n->in(0)->as_Call()->returns_pointer()) {
     472         add_local_var_and_edge(n, PointsToNode::NoEscape,
     473                                n->in(0), delayed_worklist);
     474       }
     475       break;
     476     }
     477     case Op_Rethrow: // Exception object escapes
     478     case Op_Return: {
     479       if (n->req() > TypeFunc::Parms &&
     480           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
     481         // Treat Return value as LocalVar with GlobalEscape escape state.
     482         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
     483                                n->in(TypeFunc::Parms), delayed_worklist);
     484       }
     485       break;
     486     }
     487     case Op_GetAndSetP:
     488     case Op_GetAndSetN: {
     489       add_objload_to_connection_graph(n, delayed_worklist);
     490       // fallthrough
     491     }
     492     case Op_StoreP:
     493     case Op_StoreN:
     494     case Op_StoreNKlass:
     495     case Op_StorePConditional:
     496     case Op_CompareAndSwapP:
     497     case Op_CompareAndSwapN: {
     498       Node* adr = n->in(MemNode::Address);
     499       const Type *adr_type = igvn->type(adr);
     500       adr_type = adr_type->make_ptr();
     501       if (adr_type == NULL) {
     502         break; // skip dead nodes
     503       }
     504       if (adr_type->isa_oopptr() ||
     505           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
     506                         (adr_type == TypeRawPtr::NOTNULL &&
     507                          adr->in(AddPNode::Address)->is_Proj() &&
     508                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
     509         delayed_worklist->push(n); // Process it later.
     510 #ifdef ASSERT
     511         assert(adr->is_AddP(), "expecting an AddP");
     512         if (adr_type == TypeRawPtr::NOTNULL) {
     513           // Verify a raw address for a store captured by Initialize node.
     514           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
     515           assert(offs != Type::OffsetBot, "offset must be a constant");
     516         }
     517 #endif
     518       } else {
     519         // Ignore copy the displaced header to the BoxNode (OSR compilation).
     520         if (adr->is_BoxLock())
     521           break;
     522         // Stored value escapes in unsafe access.
     523         if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
     524           // Pointer stores in G1 barriers looks like unsafe access.
     525           // Ignore such stores to be able scalar replace non-escaping
     526           // allocations.
     527           if (UseG1GC && adr->is_AddP()) {
     528             Node* base = get_addp_base(adr);
     529             if (base->Opcode() == Op_LoadP &&
     530                 base->in(MemNode::Address)->is_AddP()) {
     531               adr = base->in(MemNode::Address);
     532               Node* tls = get_addp_base(adr);
     533               if (tls->Opcode() == Op_ThreadLocal) {
     534                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
     535                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
     536                                      PtrQueue::byte_offset_of_buf())) {
     537                   break; // G1 pre barier previous oop value store.
     538                 }
     539                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
     540                                      PtrQueue::byte_offset_of_buf())) {
     541                   break; // G1 post barier card address store.
     542                 }
     543               }
     544             }
     545           }
     546           delayed_worklist->push(n); // Process unsafe access later.
     547           break;
     548         }
     549 #ifdef ASSERT
     550         n->dump(1);
     551         assert(false, "not unsafe or G1 barrier raw StoreP");
     552 #endif
     553       }
     554       break;
     555     }
     556     case Op_AryEq:
     557     case Op_StrComp:
     558     case Op_StrEquals:
     559     case Op_StrIndexOf:
     560     case Op_EncodeISOArray: {
     561       add_local_var(n, PointsToNode::ArgEscape);
     562       delayed_worklist->push(n); // Process it later.
     563       break;
     564     }
     565     case Op_ThreadLocal: {
     566       add_java_object(n, PointsToNode::ArgEscape);
     567       break;
     568     }
     569     default:
     570       ; // Do nothing for nodes not related to EA.
     571   }
     572   return;
     573 }
     574
     575 #ifdef ASSERT
     576 #define ELSE_FAIL(name)                               \
     577       /* Should not be called for not pointer type. */  \
     578       n->dump(1);                                       \
     579       assert(false, name);                              \
     580       break;
     581 #else
     582 #define ELSE_FAIL(name) \
     583       break;
     584 #endif
     585
     586 // Add final simple edges to graph.
     587 void ConnectionGraph::add_final_edges(Node *n) {
     588   PointsToNode* n_ptn = ptnode_adr(n->_idx);
     589 #ifdef ASSERT
     590   if (_verify && n_ptn->is_JavaObject())
     591     return; // This method does not change graph for JavaObject.
     592 #endif
     593
     594   if (n->is_Call()) {
     595     process_call_arguments(n->as_Call());
     596     return;
     597   }
     598   assert(n->is_Store() || n->is_LoadStore() ||
     599          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
     600          "node should be registered already");
     601   int opcode = n->Opcode();
     602   switch (opcode) {
     603     case Op_AddP: {
     604       Node* base = get_addp_base(n);
     605       PointsToNode* ptn_base = ptnode_adr(base->_idx);
     606       assert(ptn_base != NULL, "field's base should be registered");
     607       add_base(n_ptn->as_Field(), ptn_base);
     608       break;
     609     }
     610     case Op_CastPP:
     611     case Op_CheckCastPP:
     612     case Op_EncodeP:
     613     case Op_DecodeN:
     614     case Op_EncodePKlass:
     615     case Op_DecodeNKlass: {
     616       add_local_var_and_edge(n, PointsToNode::NoEscape,
     617                              n->in(1), NULL);
     618       break;
     619     }
     620     case Op_CMoveP: {
     621       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
     622         Node* in = n->in(i);
     623         if (in == NULL)
     624           continue;  // ignore NULL
     625         Node* uncast_in = in->uncast();
     626         if (uncast_in->is_top() || uncast_in == n)
     627           continue;  // ignore top or inputs which go back this node
     628         PointsToNode* ptn = ptnode_adr(in->_idx);
     629         assert(ptn != NULL, "node should be registered");
     630         add_edge(n_ptn, ptn);
     631       }
     632       break;
     633     }
     634     case Op_LoadP:
     635     case Op_LoadN:
     636     case Op_LoadPLocked: {
     637       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
     638       // ThreadLocal has RawPtr type.
     639       const Type* t = _igvn->type(n);
     640       if (t->make_ptr() != NULL) {
     641         Node* adr = n->in(MemNode::Address);
     642         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
     643         break;
     644       }
     645       ELSE_FAIL("Op_LoadP");
     646     }
     647     case Op_Phi: {
     648       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
     649       // ThreadLocal has RawPtr type.
     650       const Type* t = n->as_Phi()->type();
     651       if (t->make_ptr() != NULL) {
     652         for (uint i = 1; i < n->req(); i++) {
     653           Node* in = n->in(i);
     654           if (in == NULL)
     655             continue;  // ignore NULL
     656           Node* uncast_in = in->uncast();
     657           if (uncast_in->is_top() || uncast_in == n)
     658             continue;  // ignore top or inputs which go back this node
     659           PointsToNode* ptn = ptnode_adr(in->_idx);
     660           assert(ptn != NULL, "node should be registered");
     661           add_edge(n_ptn, ptn);
     662         }
     663         break;
     664       }
     665       ELSE_FAIL("Op_Phi");
     666     }
     667     case Op_Proj: {
     668       // we are only interested in the oop result projection from a call
     669       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
     670           n->in(0)->as_Call()->returns_pointer()) {
     671         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
     672         break;
     673       }
     674       ELSE_FAIL("Op_Proj");
     675     }
     676     case Op_Rethrow: // Exception object escapes
     677     case Op_Return: {
     678       if (n->req() > TypeFunc::Parms &&
     679           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
     680         // Treat Return value as LocalVar with GlobalEscape escape state.
     681         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
     682                                n->in(TypeFunc::Parms), NULL);
     683         break;
     684       }
     685       ELSE_FAIL("Op_Return");
     686     }
     687     case Op_StoreP:
     688     case Op_StoreN:
     689     case Op_StoreNKlass:
     690     case Op_StorePConditional:
     691     case Op_CompareAndSwapP:
     692     case Op_CompareAndSwapN:
     693     case Op_GetAndSetP:
     694     case Op_GetAndSetN: {
     695       Node* adr = n->in(MemNode::Address);
     696       const Type *adr_type = _igvn->type(adr);
     697       adr_type = adr_type->make_ptr();
     698 #ifdef ASSERT
     699       if (adr_type == NULL) {
     700         n->dump(1);
     701         assert(adr_type != NULL, "dead node should not be on list");
     702         break;
     703       }
     704 #endif
     705       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
     706         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
     707       }
     708       if (adr_type->isa_oopptr() ||
     709           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
     710                         (adr_type == TypeRawPtr::NOTNULL &&
     711                          adr->in(AddPNode::Address)->is_Proj() &&
     712                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
     713         // Point Address to Value
     714         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
     715         assert(adr_ptn != NULL &&
     716                adr_ptn->as_Field()->is_oop(), "node should be registered");
     717         Node *val = n->in(MemNode::ValueIn);
     718         PointsToNode* ptn = ptnode_adr(val->_idx);
     719         assert(ptn != NULL, "node should be registered");
     720         add_edge(adr_ptn, ptn);
     721         break;
     722       } else if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
     723         // Stored value escapes in unsafe access.
     724         Node *val = n->in(MemNode::ValueIn);
     725         PointsToNode* ptn = ptnode_adr(val->_idx);
     726         assert(ptn != NULL, "node should be registered");
     727         set_escape_state(ptn, PointsToNode::GlobalEscape);
     728         // Add edge to object for unsafe access with offset.
     729         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
     730         assert(adr_ptn != NULL, "node should be registered");
     731         if (adr_ptn->is_Field()) {
     732           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
     733           add_edge(adr_ptn, ptn);
     734         }
     735         break;
     736       }
     737       ELSE_FAIL("Op_StoreP");
     738     }
     739     case Op_AryEq:
     740     case Op_StrComp:
     741     case Op_StrEquals:
     742     case Op_StrIndexOf:
     743     case Op_EncodeISOArray: {
     744       // char[] arrays passed to string intrinsic do not escape but
     745       // they are not scalar replaceable. Adjust escape state for them.
     746       // Start from in(2) edge since in(1) is memory edge.
     747       for (uint i = 2; i < n->req(); i++) {
     748         Node* adr = n->in(i);
     749         const Type* at = _igvn->type(adr);
     750         if (!adr->is_top() && at->isa_ptr()) {
     751           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
     752                  at->isa_ptr() != NULL, "expecting a pointer");
     753           if (adr->is_AddP()) {
     754             adr = get_addp_base(adr);
     755           }
     756           PointsToNode* ptn = ptnode_adr(adr->_idx);
     757           assert(ptn != NULL, "node should be registered");
     758           add_edge(n_ptn, ptn);
     759         }
     760       }
     761       break;
     762     }
     763     default: {
     764       // This method should be called only for EA specific nodes which may
     765       // miss some edges when they were created.
     766 #ifdef ASSERT
     767       n->dump(1);
     768 #endif
     769       guarantee(false, "unknown node");
     770     }
     771   }
     772   return;
     773 }
     774
     775 void ConnectionGraph::add_call_node(CallNode* call) {
     776   assert(call->returns_pointer(), "only for call which returns pointer");
     777   uint call_idx = call->_idx;
     778   if (call->is_Allocate()) {
     779     Node* k = call->in(AllocateNode::KlassNode);
     780     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
     781     assert(kt != NULL, "TypeKlassPtr  required.");
     782     ciKlass* cik = kt->klass();
     783     PointsToNode::EscapeState es = PointsToNode::NoEscape;
     784     bool scalar_replaceable = true;
     785     if (call->is_AllocateArray()) {
     786       if (!cik->is_array_klass()) { // StressReflectiveCode
     787         es = PointsToNode::GlobalEscape;
     788       } else {
     789         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
     790         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
     791           // Not scalar replaceable if the length is not constant or too big.
     792           scalar_replaceable = false;
     793         }
     794       }
     795     } else {  // Allocate instance
     796       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
     797           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
     798          !cik->is_instance_klass() || // StressReflectiveCode
     799           cik->as_instance_klass()->has_finalizer()) {
     800         es = PointsToNode::GlobalEscape;
     801       }
     802     }
     803     add_java_object(call, es);
     804     PointsToNode* ptn = ptnode_adr(call_idx);
     805     if (!scalar_replaceable && ptn->scalar_replaceable()) {
     806       ptn->set_scalar_replaceable(false);
     807     }
     808   } else if (call->is_CallStaticJava()) {
     809     // Call nodes could be different types:
     810     //
     811     // 1. CallDynamicJavaNode (what happened during call is unknown):
     812     //
     813     //    - mapped to GlobalEscape JavaObject node if oop is returned;
     814     //
     815     //    - all oop arguments are escaping globally;
     816     //
     817     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
     818     //
     819     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
     820     //
     821     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
     822     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
     823     //      during call is returned;
     824     //    - mapped to ArgEscape LocalVar node pointed to object arguments
     825     //      which are returned and does not escape during call;
     826     //
     827     //    - oop arguments escaping status is defined by bytecode analysis;
     828     //
     829     // For a static call, we know exactly what method is being called.
     830     // Use bytecode estimator to record whether the call's return value escapes.
     831     ciMethod* meth = call->as_CallJava()->method();
     832     if (meth == NULL) {
     833       const char* name = call->as_CallStaticJava()->_name;
     834       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
     835       // Returns a newly allocated unescaped object.
     836       add_java_object(call, PointsToNode::NoEscape);
     837       ptnode_adr(call_idx)->set_scalar_replaceable(false);
     838     } else if (meth->is_boxing_method()) {
     839       // Returns boxing object
     840       PointsToNode::EscapeState es;
     841       vmIntrinsics::ID intr = meth->intrinsic_id();
     842       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
     843         // It does not escape if object is always allocated.
     844         es = PointsToNode::NoEscape;
     845       } else {
     846         // It escapes globally if object could be loaded from cache.
     847         es = PointsToNode::GlobalEscape;
     848       }
     849       add_java_object(call, es);
     850     } else {
     851       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
     852       call_analyzer->copy_dependencies(_compile->dependencies());
     853       if (call_analyzer->is_return_allocated()) {
     854         // Returns a newly allocated unescaped object, simply
     855         // update dependency information.
     856         // Mark it as NoEscape so that objects referenced by
     857         // it's fields will be marked as NoEscape at least.
     858         add_java_object(call, PointsToNode::NoEscape);
     859         ptnode_adr(call_idx)->set_scalar_replaceable(false);
     860       } else {
     861         // Determine whether any arguments are returned.
     862         const TypeTuple* d = call->tf()->domain();
     863         bool ret_arg = false;
     864         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
     865           if (d->field_at(i)->isa_ptr() != NULL &&
     866               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
     867             ret_arg = true;
     868             break;
     869           }
     870         }
     871         if (ret_arg) {
     872           add_local_var(call, PointsToNode::ArgEscape);
     873         } else {
     874           // Returns unknown object.
     875           map_ideal_node(call, phantom_obj);
     876         }
     877       }
     878     }
     879   } else {
     880     // An other type of call, assume the worst case:
     881     // returned value is unknown and globally escapes.
     882     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
     883     map_ideal_node(call, phantom_obj);
     884   }
     885 }
     886
     887 void ConnectionGraph::process_call_arguments(CallNode *call) {
     888     bool is_arraycopy = false;
     889     switch (call->Opcode()) {
     890 #ifdef ASSERT
     891     case Op_Allocate:
     892     case Op_AllocateArray:
     893     case Op_Lock:
     894     case Op_Unlock:
     895       assert(false, "should be done already");
     896       break;
     897 #endif
     898     case Op_ArrayCopy:
     899     case Op_CallLeafNoFP:
     900       // Most array copies are ArrayCopy nodes at this point but there
     901       // are still a few direct calls to the copy subroutines (See
     902       // PhaseStringOpts::copy_string())
     903       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
     904         (call->as_CallLeaf()->_name != NULL &&
     905          strstr(call->as_CallLeaf()->_name, "arraycopy") != 0);
     906       // fall through
     907     case Op_CallLeaf: {
     908       // Stub calls, objects do not escape but they are not scale replaceable.
     909       // Adjust escape state for outgoing arguments.
     910       const TypeTuple * d = call->tf()->domain();
     911       bool src_has_oops = false;
     912       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
     913         const Type* at = d->field_at(i);
     914         Node *arg = call->in(i);
     915         if (arg == NULL) {
     916           continue;
     917         }
     918         const Type *aat = _igvn->type(arg);
     919         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
     920           continue;
     921         if (arg->is_AddP()) {
     922           //
     923           // The inline_native_clone() case when the arraycopy stub is called
     924           // after the allocation before Initialize and CheckCastPP nodes.
     925           // Or normal arraycopy for object arrays case.
     926           //
     927           // Set AddP's base (Allocate) as not scalar replaceable since
     928           // pointer to the base (with offset) is passed as argument.
     929           //
     930           arg = get_addp_base(arg);
     931         }
     932         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
     933         assert(arg_ptn != NULL, "should be registered");
     934         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
     935         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
     936           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
     937                  aat->isa_ptr() != NULL, "expecting an Ptr");
     938           bool arg_has_oops = aat->isa_oopptr() &&
     939                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
     940                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
     941           if (i == TypeFunc::Parms) {
     942             src_has_oops = arg_has_oops;
     943           }
     944           //
     945           // src or dst could be j.l.Object when other is basic type array:
     946           //
     947           //   arraycopy(char[],0,Object*,0,size);
     948           //   arraycopy(Object*,0,char[],0,size);
     949           //
     950           // Don't add edges in such cases.
     951           //
     952           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
     953                                        arg_has_oops && (i > TypeFunc::Parms);
     954 #ifdef ASSERT
     955           if (!(is_arraycopy ||
     956                 (call->as_CallLeaf()->_name != NULL &&
     957                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
     958                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
     959                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
     960                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
     961                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
     962                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
     963                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
     964                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
     965                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
     966                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
     967                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
     968                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
     969                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
     970                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
     971                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
     972                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0)
     973                   ))) {
     974             call->dump();
     975             fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
     976           }
     977 #endif
     978           // Always process arraycopy's destination object since
     979           // we need to add all possible edges to references in
     980           // source object.
     981           if (arg_esc >= PointsToNode::ArgEscape &&
     982               !arg_is_arraycopy_dest) {
     983             continue;
     984           }
     985           set_escape_state(arg_ptn, PointsToNode::ArgEscape);
     986           if (arg_is_arraycopy_dest) {
     987             Node* src = call->in(TypeFunc::Parms);
     988             if (src->is_AddP()) {
     989               src = get_addp_base(src);
     990             }
     991             PointsToNode* src_ptn = ptnode_adr(src->_idx);
     992             assert(src_ptn != NULL, "should be registered");
     993             if (arg_ptn != src_ptn) {
     994               // Special arraycopy edge:
     995               // A destination object's field can't have the source object
     996               // as base since objects escape states are not related.
     997               // Only escape state of destination object's fields affects
     998               // escape state of fields in source object.
     999               add_arraycopy(call, PointsToNode::ArgEscape, src_ptn, arg_ptn);
    1000             }
    1001           }
    1002         }
    1003       }
    1004       break;
    1005     }
    1006     case Op_CallStaticJava: {
    1007       // For a static call, we know exactly what method is being called.
    1008       // Use bytecode estimator to record the call's escape affects
    1009 #ifdef ASSERT
    1010       const char* name = call->as_CallStaticJava()->_name;
    1011       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
    1012 #endif
    1013       ciMethod* meth = call->as_CallJava()->method();
    1014       if ((meth != NULL) && meth->is_boxing_method()) {
    1015         break; // Boxing methods do not modify any oops.
    1016       }
    1017       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
    1018       // fall-through if not a Java method or no analyzer information
    1019       if (call_analyzer != NULL) {
    1020         PointsToNode* call_ptn = ptnode_adr(call->_idx);
    1021         const TypeTuple* d = call->tf()->domain();
    1022         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
    1023           const Type* at = d->field_at(i);
    1024           int k = i - TypeFunc::Parms;
    1025           Node* arg = call->in(i);
    1026           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
    1027           if (at->isa_ptr() != NULL &&
    1028               call_analyzer->is_arg_returned(k)) {
    1029             // The call returns arguments.
    1030             if (call_ptn != NULL) { // Is call's result used?
    1031               assert(call_ptn->is_LocalVar(), "node should be registered");
    1032               assert(arg_ptn != NULL, "node should be registered");
    1033               add_edge(call_ptn, arg_ptn);
    1034             }
    1035           }
    1036           if (at->isa_oopptr() != NULL &&
    1037               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
    1038             if (!call_analyzer->is_arg_stack(k)) {
    1039               // The argument global escapes
    1040               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
    1041             } else {
    1042               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
    1043               if (!call_analyzer->is_arg_local(k)) {
    1044                 // The argument itself doesn't escape, but any fields might
    1045                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
    1046               }
    1047             }
    1048           }
    1049         }
    1050         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
    1051           // The call returns arguments.
    1052           assert(call_ptn->edge_count() > 0, "sanity");
    1053           if (!call_analyzer->is_return_local()) {
    1054             // Returns also unknown object.
    1055             add_edge(call_ptn, phantom_obj);
    1056           }
    1057         }
    1058         break;
    1059       }
    1060     }
    1061     default: {
    1062       // Fall-through here if not a Java method or no analyzer information
    1063       // or some other type of call, assume the worst case: all arguments
    1064       // globally escape.
    1065       const TypeTuple* d = call->tf()->domain();
    1066       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
    1067         const Type* at = d->field_at(i);
    1068         if (at->isa_oopptr() != NULL) {
    1069           Node* arg = call->in(i);
    1070           if (arg->is_AddP()) {
    1071             arg = get_addp_base(arg);
    1072           }
    1073           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
    1074           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
    1075         }
    1076       }
    1077     }
    1078   }
    1079 }
    1080
    1081
    1082 // Finish Graph construction.
    1083 bool ConnectionGraph::complete_connection_graph(
    1084                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
    1085                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
    1086                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
    1087                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
    1088   // Normally only 1-3 passes needed to build Connection Graph depending
    1089   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
    1090   // Set limit to 20 to catch situation when something did go wrong and
    1091   // bailout Escape Analysis.
    1092   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
    1093 #define CG_BUILD_ITER_LIMIT 20
    1094
    1095   // Propagate GlobalEscape and ArgEscape escape states and check that
    1096   // we still have non-escaping objects. The method pushs on _worklist
    1097   // Field nodes which reference phantom_object.
    1098   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
    1099     return false; // Nothing to do.
    1100   }
    1101   // Now propagate references to all JavaObject nodes.
    1102   int java_objects_length = java_objects_worklist.length();
    1103   elapsedTimer time;
    1104   bool timeout = false;
    1105   int new_edges = 1;
    1106   int iterations = 0;
    1107   do {
    1108     while ((new_edges > 0) &&
    1109            (iterations++ < CG_BUILD_ITER_LIMIT)) {
    1110       double start_time = time.seconds();
    1111       time.start();
    1112       new_edges = 0;
    1113       // Propagate references to phantom_object for nodes pushed on _worklist
    1114       // by find_non_escaped_objects() and find_field_value().
    1115       new_edges += add_java_object_edges(phantom_obj, false);
    1116       for (int next = 0; next < java_objects_length; ++next) {
    1117         JavaObjectNode* ptn = java_objects_worklist.at(next);
    1118         new_edges += add_java_object_edges(ptn, true);
    1119
    1120 #define SAMPLE_SIZE 4
    1121         if ((next % SAMPLE_SIZE) == 0) {
    1122           // Each 4 iterations calculate how much time it will take
    1123           // to complete graph construction.
    1124           time.stop();
    1125           // Poll for requests from shutdown mechanism to quiesce compiler
    1126           // because Connection graph construction may take long time.
    1127           CompileBroker::maybe_block();
    1128           double stop_time = time.seconds();
    1129           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
    1130           double time_until_end = time_per_iter * (double)(java_objects_length - next);
    1131           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
    1132             timeout = true;
    1133             break; // Timeout
    1134           }
    1135           start_time = stop_time;
    1136           time.start();
    1137         }
    1138 #undef SAMPLE_SIZE
    1139
    1140       }
    1141       if (timeout) break;
    1142       if (new_edges > 0) {
    1143         // Update escape states on each iteration if graph was updated.
    1144         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
    1145           return false; // Nothing to do.
    1146         }
    1147       }
    1148       time.stop();
    1149       if (time.seconds() >= EscapeAnalysisTimeout) {
    1150         timeout = true;
    1151         break;
    1152       }
    1153     }
    1154     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
    1155       time.start();
    1156       // Find fields which have unknown value.
    1157       int fields_length = oop_fields_worklist.length();
    1158       for (int next = 0; next < fields_length; next++) {
    1159         FieldNode* field = oop_fields_worklist.at(next);
    1160         if (field->edge_count() == 0) {
    1161           new_edges += find_field_value(field);
    1162           // This code may added new edges to phantom_object.
    1163           // Need an other cycle to propagate references to phantom_object.
    1164         }
    1165       }
    1166       time.stop();
    1167       if (time.seconds() >= EscapeAnalysisTimeout) {
    1168         timeout = true;
    1169         break;
    1170       }
    1171     } else {
    1172       new_edges = 0; // Bailout
    1173     }
    1174   } while (new_edges > 0);
    1175
    1176   // Bailout if passed limits.
    1177   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
    1178     Compile* C = _compile;
    1179     if (C->log() != NULL) {
    1180       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
    1181       C->log()->text("%s", timeout ? "time" : "iterations");
    1182       C->log()->end_elem(" limit'");
    1183     }
    1184     assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
    1185            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
    1186     // Possible infinite build_connection_graph loop,
    1187     // bailout (no changes to ideal graph were made).
    1188     return false;
    1189   }
    1190 #ifdef ASSERT
    1191   if (Verbose && PrintEscapeAnalysis) {
    1192     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
    1193                   iterations, nodes_size(), ptnodes_worklist.length());
    1194   }
    1195 #endif
    1196
    1197 #undef CG_BUILD_ITER_LIMIT
    1198
    1199   // Find fields initialized by NULL for non-escaping Allocations.
    1200   int non_escaped_length = non_escaped_worklist.length();
    1201   for (int next = 0; next < non_escaped_length; next++) {
    1202     JavaObjectNode* ptn = non_escaped_worklist.at(next);
    1203     PointsToNode::EscapeState es = ptn->escape_state();
    1204     assert(es <= PointsToNode::ArgEscape, "sanity");
    1205     if (es == PointsToNode::NoEscape) {
    1206       if (find_init_values(ptn, null_obj, _igvn) > 0) {
    1207         // Adding references to NULL object does not change escape states
    1208         // since it does not escape. Also no fields are added to NULL object.
    1209         add_java_object_edges(null_obj, false);
    1210       }
    1211     }
    1212     Node* n = ptn->ideal_node();
    1213     if (n->is_Allocate()) {
    1214       // The object allocated by this Allocate node will never be
    1215       // seen by an other thread. Mark it so that when it is
    1216       // expanded no MemBarStoreStore is added.
    1217       InitializeNode* ini = n->as_Allocate()->initialization();
    1218       if (ini != NULL)
    1219         ini->set_does_not_escape();
    1220     }
    1221   }
    1222   return true; // Finished graph construction.
    1223 }
    1224
    1225 // Propagate GlobalEscape and ArgEscape escape states to all nodes
    1226 // and check that we still have non-escaping java objects.
    1227 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
    1228                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
    1229   GrowableArray<PointsToNode*> escape_worklist;
    1230   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
    1231   int ptnodes_length = ptnodes_worklist.length();
    1232   for (int next = 0; next < ptnodes_length; ++next) {
    1233     PointsToNode* ptn = ptnodes_worklist.at(next);
    1234     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
    1235         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
    1236       escape_worklist.push(ptn);
    1237     }
    1238   }
    1239   // Set escape states to referenced nodes (edges list).
    1240   while (escape_worklist.length() > 0) {
    1241     PointsToNode* ptn = escape_worklist.pop();
    1242     PointsToNode::EscapeState es  = ptn->escape_state();
    1243     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
    1244     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
    1245         es >= PointsToNode::ArgEscape) {
    1246       // GlobalEscape or ArgEscape state of field means it has unknown value.
    1247       if (add_edge(ptn, phantom_obj)) {
    1248         // New edge was added
    1249         add_field_uses_to_worklist(ptn->as_Field());
    1250       }
    1251     }
    1252     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
    1253       PointsToNode* e = i.get();
    1254       if (e->is_Arraycopy()) {
    1255         assert(ptn->arraycopy_dst(), "sanity");
    1256         // Propagate only fields escape state through arraycopy edge.
    1257         if (e->fields_escape_state() < field_es) {
    1258           set_fields_escape_state(e, field_es);
    1259           escape_worklist.push(e);
    1260         }
    1261       } else if (es >= field_es) {
    1262         // fields_escape_state is also set to 'es' if it is less than 'es'.
    1263         if (e->escape_state() < es) {
    1264           set_escape_state(e, es);
    1265           escape_worklist.push(e);
    1266         }
    1267       } else {
    1268         // Propagate field escape state.
    1269         bool es_changed = false;
    1270         if (e->fields_escape_state() < field_es) {
    1271           set_fields_escape_state(e, field_es);
    1272           es_changed = true;
    1273         }
    1274         if ((e->escape_state() < field_es) &&
    1275             e->is_Field() && ptn->is_JavaObject() &&
    1276             e->as_Field()->is_oop()) {
    1277           // Change escape state of referenced fileds.
    1278           set_escape_state(e, field_es);
    1279           es_changed = true;;
    1280         } else if (e->escape_state() < es) {
    1281           set_escape_state(e, es);
    1282           es_changed = true;;
    1283         }
    1284         if (es_changed) {
    1285           escape_worklist.push(e);
    1286         }
    1287       }
    1288     }
    1289   }
    1290   // Remove escaped objects from non_escaped list.
    1291   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
    1292     JavaObjectNode* ptn = non_escaped_worklist.at(next);
    1293     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
    1294       non_escaped_worklist.delete_at(next);
    1295     }
    1296     if (ptn->escape_state() == PointsToNode::NoEscape) {
    1297       // Find fields in non-escaped allocations which have unknown value.
    1298       find_init_values(ptn, phantom_obj, NULL);
    1299     }
    1300   }
    1301   return (non_escaped_worklist.length() > 0);
    1302 }
    1303
    1304 // Add all references to JavaObject node by walking over all uses.
    1305 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
    1306   int new_edges = 0;
    1307   if (populate_worklist) {
    1308     // Populate _worklist by uses of jobj's uses.
    1309     for (UseIterator i(jobj); i.has_next(); i.next()) {
    1310       PointsToNode* use = i.get();
    1311       if (use->is_Arraycopy())
    1312         continue;
    1313       add_uses_to_worklist(use);
    1314       if (use->is_Field() && use->as_Field()->is_oop()) {
    1315         // Put on worklist all field's uses (loads) and
    1316         // related field nodes (same base and offset).
    1317         add_field_uses_to_worklist(use->as_Field());
    1318       }
    1319     }
    1320   }
    1321   for (int l = 0; l < _worklist.length(); l++) {
    1322     PointsToNode* use = _worklist.at(l);
    1323     if (PointsToNode::is_base_use(use)) {
    1324       // Add reference from jobj to field and from field to jobj (field's base).
    1325       use = PointsToNode::get_use_node(use)->as_Field();
    1326       if (add_base(use->as_Field(), jobj)) {
    1327         new_edges++;
    1328       }
    1329       continue;
    1330     }
    1331     assert(!use->is_JavaObject(), "sanity");
    1332     if (use->is_Arraycopy()) {
    1333       if (jobj == null_obj) // NULL object does not have field edges
    1334         continue;
    1335       // Added edge from Arraycopy node to arraycopy's source java object
    1336       if (add_edge(use, jobj)) {
    1337         jobj->set_arraycopy_src();
    1338         new_edges++;
    1339       }
    1340       // and stop here.
    1341       continue;
    1342     }
    1343     if (!add_edge(use, jobj))
    1344       continue; // No new edge added, there was such edge already.
    1345     new_edges++;
    1346     if (use->is_LocalVar()) {
    1347       add_uses_to_worklist(use);
    1348       if (use->arraycopy_dst()) {
    1349         for (EdgeIterator i(use); i.has_next(); i.next()) {
    1350           PointsToNode* e = i.get();
    1351           if (e->is_Arraycopy()) {
    1352             if (jobj == null_obj) // NULL object does not have field edges
    1353               continue;
    1354             // Add edge from arraycopy's destination java object to Arraycopy node.
    1355             if (add_edge(jobj, e)) {
    1356               new_edges++;
    1357               jobj->set_arraycopy_dst();
    1358             }
    1359           }
    1360         }
    1361       }
    1362     } else {
    1363       // Added new edge to stored in field values.
    1364       // Put on worklist all field's uses (loads) and
    1365       // related field nodes (same base and offset).
    1366       add_field_uses_to_worklist(use->as_Field());
    1367     }
    1368   }
    1369   _worklist.clear();
    1370   _in_worklist.Reset();
    1371   return new_edges;
    1372 }
    1373
    1374 // Put on worklist all related field nodes.
    1375 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
    1376   assert(field->is_oop(), "sanity");
    1377   int offset = field->offset();
    1378   add_uses_to_worklist(field);
    1379   // Loop over all bases of this field and push on worklist Field nodes
    1380   // with the same offset and base (since they may reference the same field).
    1381   for (BaseIterator i(field); i.has_next(); i.next()) {
    1382     PointsToNode* base = i.get();
    1383     add_fields_to_worklist(field, base);
    1384     // Check if the base was source object of arraycopy and go over arraycopy's
    1385     // destination objects since values stored to a field of source object are
    1386     // accessable by uses (loads) of fields of destination objects.
    1387     if (base->arraycopy_src()) {
    1388       for (UseIterator j(base); j.has_next(); j.next()) {
    1389         PointsToNode* arycp = j.get();
    1390         if (arycp->is_Arraycopy()) {
    1391           for (UseIterator k(arycp); k.has_next(); k.next()) {
    1392             PointsToNode* abase = k.get();
    1393             if (abase->arraycopy_dst() && abase != base) {
    1394               // Look for the same arracopy reference.
    1395               add_fields_to_worklist(field, abase);
    1396             }
    1397           }
    1398         }
    1399       }
    1400     }
    1401   }
    1402 }
    1403
    1404 // Put on worklist all related field nodes.
    1405 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
    1406   int offset = field->offset();
    1407   if (base->is_LocalVar()) {
    1408     for (UseIterator j(base); j.has_next(); j.next()) {
    1409       PointsToNode* f = j.get();
    1410       if (PointsToNode::is_base_use(f)) { // Field
    1411         f = PointsToNode::get_use_node(f);
    1412         if (f == field || !f->as_Field()->is_oop())
    1413           continue;
    1414         int offs = f->as_Field()->offset();
    1415         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
    1416           add_to_worklist(f);
    1417         }
    1418       }
    1419     }
    1420   } else {
    1421     assert(base->is_JavaObject(), "sanity");
    1422     if (// Skip phantom_object since it is only used to indicate that
    1423         // this field's content globally escapes.
    1424         (base != phantom_obj) &&
    1425         // NULL object node does not have fields.
    1426         (base != null_obj)) {
    1427       for (EdgeIterator i(base); i.has_next(); i.next()) {
    1428         PointsToNode* f = i.get();
    1429         // Skip arraycopy edge since store to destination object field
    1430         // does not update value in source object field.
    1431         if (f->is_Arraycopy()) {
    1432           assert(base->arraycopy_dst(), "sanity");
    1433           continue;
    1434         }
    1435         if (f == field || !f->as_Field()->is_oop())
    1436           continue;
    1437         int offs = f->as_Field()->offset();
    1438         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
    1439           add_to_worklist(f);
    1440         }
    1441       }
    1442     }
    1443   }
    1444 }
    1445
    1446 // Find fields which have unknown value.
    1447 int ConnectionGraph::find_field_value(FieldNode* field) {
    1448   // Escaped fields should have init value already.
    1449   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
    1450   int new_edges = 0;
    1451   for (BaseIterator i(field); i.has_next(); i.next()) {
    1452     PointsToNode* base = i.get();
    1453     if (base->is_JavaObject()) {
    1454       // Skip Allocate's fields which will be processed later.
    1455       if (base->ideal_node()->is_Allocate())
    1456         return 0;
    1457       assert(base == null_obj, "only NULL ptr base expected here");
    1458     }
    1459   }
    1460   if (add_edge(field, phantom_obj)) {
    1461     // New edge was added
    1462     new_edges++;
    1463     add_field_uses_to_worklist(field);
    1464   }
    1465   return new_edges;
    1466 }
    1467
    1468 // Find fields initializing values for allocations.
    1469 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
    1470   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
    1471   int new_edges = 0;
    1472   Node* alloc = pta->ideal_node();
    1473   if (init_val == phantom_obj) {
    1474     // Do nothing for Allocate nodes since its fields values are "known".
    1475     if (alloc->is_Allocate())
    1476       return 0;
    1477     assert(alloc->as_CallStaticJava(), "sanity");
    1478 #ifdef ASSERT
    1479     if (alloc->as_CallStaticJava()->method() == NULL) {
    1480       const char* name = alloc->as_CallStaticJava()->_name;
    1481       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
    1482     }
    1483 #endif
    1484     // Non-escaped allocation returned from Java or runtime call have
    1485     // unknown values in fields.
    1486     for (EdgeIterator i(pta); i.has_next(); i.next()) {
    1487       PointsToNode* field = i.get();
    1488       if (field->is_Field() && field->as_Field()->is_oop()) {
    1489         if (add_edge(field, phantom_obj)) {
    1490           // New edge was added
    1491           new_edges++;
    1492           add_field_uses_to_worklist(field->as_Field());
    1493         }
    1494       }
    1495     }
    1496     return new_edges;
    1497   }
    1498   assert(init_val == null_obj, "sanity");
    1499   // Do nothing for Call nodes since its fields values are unknown.
    1500   if (!alloc->is_Allocate())
    1501     return 0;
    1502
    1503   InitializeNode* ini = alloc->as_Allocate()->initialization();
    1504   bool visited_bottom_offset = false;
    1505   GrowableArray<int> offsets_worklist;
    1506
    1507   // Check if an oop field's initializing value is recorded and add
    1508   // a corresponding NULL if field's value if it is not recorded.
    1509   // Connection Graph does not record a default initialization by NULL
    1510   // captured by Initialize node.
    1511   //
    1512   for (EdgeIterator i(pta); i.has_next(); i.next()) {
    1513     PointsToNode* field = i.get(); // Field (AddP)
    1514     if (!field->is_Field() || !field->as_Field()->is_oop())
    1515       continue; // Not oop field
    1516     int offset = field->as_Field()->offset();
    1517     if (offset == Type::OffsetBot) {
    1518       if (!visited_bottom_offset) {
    1519         // OffsetBot is used to reference array's element,
    1520         // always add reference to NULL to all Field nodes since we don't
    1521         // known which element is referenced.
    1522         if (add_edge(field, null_obj)) {
    1523           // New edge was added
    1524           new_edges++;
    1525           add_field_uses_to_worklist(field->as_Field());
    1526           visited_bottom_offset = true;
    1527         }
    1528       }
    1529     } else {
    1530       // Check only oop fields.
    1531       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
    1532       if (adr_type->isa_rawptr()) {
    1533 #ifdef ASSERT
    1534         // Raw pointers are used for initializing stores so skip it
    1535         // since it should be recorded already
    1536         Node* base = get_addp_base(field->ideal_node());
    1537         assert(adr_type->isa_rawptr() && base->is_Proj() &&
    1538                (base->in(0) == alloc),"unexpected pointer type");
    1539 #endif
    1540         continue;
    1541       }
    1542       if (!offsets_worklist.contains(offset)) {
    1543         offsets_worklist.append(offset);
    1544         Node* value = NULL;
    1545         if (ini != NULL) {
    1546           // StoreP::memory_type() == T_ADDRESS
    1547           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
    1548           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
    1549           // Make sure initializing store has the same type as this AddP.
    1550           // This AddP may reference non existing field because it is on a
    1551           // dead branch of bimorphic call which is not eliminated yet.
    1552           if (store != NULL && store->is_Store() &&
    1553               store->as_Store()->memory_type() == ft) {
    1554             value = store->in(MemNode::ValueIn);
    1555 #ifdef ASSERT
    1556             if (VerifyConnectionGraph) {
    1557               // Verify that AddP already points to all objects the value points to.
    1558               PointsToNode* val = ptnode_adr(value->_idx);
    1559               assert((val != NULL), "should be processed already");
    1560               PointsToNode* missed_obj = NULL;
    1561               if (val->is_JavaObject()) {
    1562                 if (!field->points_to(val->as_JavaObject())) {
    1563                   missed_obj = val;
    1564                 }
    1565               } else {
    1566                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
    1567                   tty->print_cr("----------init store has invalid value -----");
    1568                   store->dump();
    1569                   val->dump();
    1570                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
    1571                 }
    1572                 for (EdgeIterator j(val); j.has_next(); j.next()) {
    1573                   PointsToNode* obj = j.get();
    1574                   if (obj->is_JavaObject()) {
    1575                     if (!field->points_to(obj->as_JavaObject())) {
    1576                       missed_obj = obj;
    1577                       break;
    1578                     }
    1579                   }
    1580                 }
    1581               }
    1582               if (missed_obj != NULL) {
    1583                 tty->print_cr("----------field---------------------------------");
    1584                 field->dump();
    1585                 tty->print_cr("----------missed referernce to object-----------");
    1586                 missed_obj->dump();
    1587                 tty->print_cr("----------object referernced by init store -----");
    1588                 store->dump();
    1589                 val->dump();
    1590                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
    1591               }
    1592             }
    1593 #endif
    1594           } else {
    1595             // There could be initializing stores which follow allocation.
    1596             // For example, a volatile field store is not collected
    1597             // by Initialize node.
    1598             //
    1599             // Need to check for dependent loads to separate such stores from
    1600             // stores which follow loads. For now, add initial value NULL so
    1601             // that compare pointers optimization works correctly.
    1602           }
    1603         }
    1604         if (value == NULL) {
    1605           // A field's initializing value was not recorded. Add NULL.
    1606           if (add_edge(field, null_obj)) {
    1607             // New edge was added
    1608             new_edges++;
    1609             add_field_uses_to_worklist(field->as_Field());
    1610           }
    1611         }
    1612       }
    1613     }
    1614   }
    1615   return new_edges;
    1616 }
    1617
    1618 // Adjust scalar_replaceable state after Connection Graph is built.
    1619 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
    1620   // Search for non-escaping objects which are not scalar replaceable
    1621   // and mark them to propagate the state to referenced objects.
    1622
    1623   // 1. An object is not scalar replaceable if the field into which it is
    1624   // stored has unknown offset (stored into unknown element of an array).
    1625   //
    1626   for (UseIterator i(jobj); i.has_next(); i.next()) {
    1627     PointsToNode* use = i.get();
    1628     assert(!use->is_Arraycopy(), "sanity");
    1629     if (use->is_Field()) {
    1630       FieldNode* field = use->as_Field();
    1631       assert(field->is_oop() && field->scalar_replaceable() &&
    1632              field->fields_escape_state() == PointsToNode::NoEscape, "sanity");
    1633       if (field->offset() == Type::OffsetBot) {
    1634         jobj->set_scalar_replaceable(false);
    1635         return;
    1636       }
    1637       // 2. An object is not scalar replaceable if the field into which it is
    1638       // stored has multiple bases one of which is null.
    1639       if (field->base_count() > 1) {
    1640         for (BaseIterator i(field); i.has_next(); i.next()) {
    1641           PointsToNode* base = i.get();
    1642           if (base == null_obj) {
    1643             jobj->set_scalar_replaceable(false);
    1644             return;
    1645           }
    1646         }
    1647       }
    1648     }
    1649     assert(use->is_Field() || use->is_LocalVar(), "sanity");
    1650     // 3. An object is not scalar replaceable if it is merged with other objects.
    1651     for (EdgeIterator j(use); j.has_next(); j.next()) {
    1652       PointsToNode* ptn = j.get();
    1653       if (ptn->is_JavaObject() && ptn != jobj) {
    1654         // Mark all objects.
    1655         jobj->set_scalar_replaceable(false);
    1656          ptn->set_scalar_replaceable(false);
    1657       }
    1658     }
    1659     if (!jobj->scalar_replaceable()) {
    1660       return;
    1661     }
    1662   }
    1663
    1664   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
    1665     // Non-escaping object node should point only to field nodes.
    1666     FieldNode* field = j.get()->as_Field();
    1667     int offset = field->as_Field()->offset();
    1668
    1669     // 4. An object is not scalar replaceable if it has a field with unknown
    1670     // offset (array's element is accessed in loop).
    1671     if (offset == Type::OffsetBot) {
    1672       jobj->set_scalar_replaceable(false);
    1673       return;
    1674     }
    1675     // 5. Currently an object is not scalar replaceable if a LoadStore node
    1676     // access its field since the field value is unknown after it.
    1677     //
    1678     Node* n = field->ideal_node();
    1679     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
    1680       if (n->fast_out(i)->is_LoadStore()) {
    1681         jobj->set_scalar_replaceable(false);
    1682         return;
    1683       }
    1684     }
    1685
    1686     // 6. Or the address may point to more then one object. This may produce
    1687     // the false positive result (set not scalar replaceable)
    1688     // since the flow-insensitive escape analysis can't separate
    1689     // the case when stores overwrite the field's value from the case
    1690     // when stores happened on different control branches.
    1691     //
    1692     // Note: it will disable scalar replacement in some cases:
    1693     //
    1694     //    Point p[] = new Point[1];
    1695     //    p[0] = new Point(); // Will be not scalar replaced
    1696     //
    1697     // but it will save us from incorrect optimizations in next cases:
    1698     //
    1699     //    Point p[] = new Point[1];
    1700     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
    1701     //
    1702     if (field->base_count() > 1) {
    1703       for (BaseIterator i(field); i.has_next(); i.next()) {
    1704         PointsToNode* base = i.get();
    1705         // Don't take into account LocalVar nodes which
    1706         // may point to only one object which should be also
    1707         // this field's base by now.
    1708         if (base->is_JavaObject() && base != jobj) {
    1709           // Mark all bases.
    1710           jobj->set_scalar_replaceable(false);
    1711           base->set_scalar_replaceable(false);
    1712         }
    1713       }
    1714     }
    1715   }
    1716 }
    1717
    1718 #ifdef ASSERT
    1719 void ConnectionGraph::verify_connection_graph(
    1720                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
    1721                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
    1722                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
    1723                          GrowableArray<Node*>& addp_worklist) {
    1724   // Verify that graph is complete - no new edges could be added.
    1725   int java_objects_length = java_objects_worklist.length();
    1726   int non_escaped_length  = non_escaped_worklist.length();
    1727   int new_edges = 0;
    1728   for (int next = 0; next < java_objects_length; ++next) {
    1729     JavaObjectNode* ptn = java_objects_worklist.at(next);
    1730     new_edges += add_java_object_edges(ptn, true);
    1731   }
    1732   assert(new_edges == 0, "graph was not complete");
    1733   // Verify that escape state is final.
    1734   int length = non_escaped_worklist.length();
    1735   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
    1736   assert((non_escaped_length == non_escaped_worklist.length()) &&
    1737          (non_escaped_length == length) &&
    1738          (_worklist.length() == 0), "escape state was not final");
    1739
    1740   // Verify fields information.
    1741   int addp_length = addp_worklist.length();
    1742   for (int next = 0; next < addp_length; ++next ) {
    1743     Node* n = addp_worklist.at(next);
    1744     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
    1745     if (field->is_oop()) {
    1746       // Verify that field has all bases
    1747       Node* base = get_addp_base(n);
    1748       PointsToNode* ptn = ptnode_adr(base->_idx);
    1749       if (ptn->is_JavaObject()) {
    1750         assert(field->has_base(ptn->as_JavaObject()), "sanity");
    1751       } else {
    1752         assert(ptn->is_LocalVar(), "sanity");
    1753         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
    1754           PointsToNode* e = i.get();
    1755           if (e->is_JavaObject()) {
    1756             assert(field->has_base(e->as_JavaObject()), "sanity");
    1757           }
    1758         }
    1759       }
    1760       // Verify that all fields have initializing values.
    1761       if (field->edge_count() == 0) {
    1762         tty->print_cr("----------field does not have references----------");
    1763         field->dump();
    1764         for (BaseIterator i(field); i.has_next(); i.next()) {
    1765           PointsToNode* base = i.get();
    1766           tty->print_cr("----------field has next base---------------------");
    1767           base->dump();
    1768           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
    1769             tty->print_cr("----------base has fields-------------------------");
    1770             for (EdgeIterator j(base); j.has_next(); j.next()) {
    1771               j.get()->dump();
    1772             }
    1773             tty->print_cr("----------base has references---------------------");
    1774             for (UseIterator j(base); j.has_next(); j.next()) {
    1775               j.get()->dump();
    1776             }
    1777           }
    1778         }
    1779         for (UseIterator i(field); i.has_next(); i.next()) {
    1780           i.get()->dump();
    1781         }
    1782         assert(field->edge_count() > 0, "sanity");
    1783       }
    1784     }
    1785   }
    1786 }
    1787 #endif
    1788
    1789 // Optimize ideal graph.
    1790 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
    1791                                            GrowableArray<Node*>& storestore_worklist) {
    1792   Compile* C = _compile;
    1793   PhaseIterGVN* igvn = _igvn;
    1794   if (EliminateLocks) {
    1795     // Mark locks before changing ideal graph.
    1796     int cnt = C->macro_count();
    1797     for( int i=0; i < cnt; i++ ) {
    1798       Node *n = C->macro_node(i);
    1799       if (n->is_AbstractLock()) { // Lock and Unlock nodes
    1800         AbstractLockNode* alock = n->as_AbstractLock();
    1801         if (!alock->is_non_esc_obj()) {
    1802           if (not_global_escape(alock->obj_node())) {
    1803             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
    1804             // The lock could be marked eliminated by lock coarsening
    1805             // code during first IGVN before EA. Replace coarsened flag
    1806             // to eliminate all associated locks/unlocks.
    1807 #ifdef ASSERT
    1808             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
    1809 #endif
    1810             alock->set_non_esc_obj();
    1811           }
    1812         }
    1813       }
    1814     }
    1815   }
    1816
    1817   if (OptimizePtrCompare) {
    1818     // Add ConI(#CC_GT) and ConI(#CC_EQ).
    1819     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
    1820     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
    1821     // Optimize objects compare.
    1822     while (ptr_cmp_worklist.length() != 0) {
    1823       Node *n = ptr_cmp_worklist.pop();
    1824       Node *res = optimize_ptr_compare(n);
    1825       if (res != NULL) {
    1826 #ifndef PRODUCT
    1827         if (PrintOptimizePtrCompare) {
    1828           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"));
    1829           if (Verbose) {
    1830             n->dump(1);
    1831           }
    1832         }
    1833 #endif
    1834         igvn->replace_node(n, res);
    1835       }
    1836     }
    1837     // cleanup
    1838     if (_pcmp_neq->outcnt() == 0)
    1839       igvn->hash_delete(_pcmp_neq);
    1840     if (_pcmp_eq->outcnt()  == 0)
    1841       igvn->hash_delete(_pcmp_eq);
    1842   }
    1843
    1844   // For MemBarStoreStore nodes added in library_call.cpp, check
    1845   // escape status of associated AllocateNode and optimize out
    1846   // MemBarStoreStore node if the allocated object never escapes.
    1847   while (storestore_worklist.length() != 0) {
    1848     Node *n = storestore_worklist.pop();
    1849     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
    1850     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
    1851     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
    1852     if (not_global_escape(alloc)) {
    1853       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
    1854       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
    1855       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
    1856       igvn->register_new_node_with_optimizer(mb);
    1857       igvn->replace_node(storestore, mb);
    1858     }
    1859   }
    1860 }
    1861
    1862 // Optimize objects compare.
    1863 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
    1864   assert(OptimizePtrCompare, "sanity");
    1865   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
    1866   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
    1867   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
    1868   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
    1869   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
    1870   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
    1871
    1872   // Check simple cases first.
    1873   if (jobj1 != NULL) {
    1874     if (jobj1->escape_state() == PointsToNode::NoEscape) {
    1875       if (jobj1 == jobj2) {
    1876         // Comparing the same not escaping object.
    1877         return _pcmp_eq;
    1878       }
    1879       Node* obj = jobj1->ideal_node();
    1880       // Comparing not escaping allocation.
    1881       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
    1882           !ptn2->points_to(jobj1)) {
    1883         return _pcmp_neq; // This includes nullness check.
    1884       }
    1885     }
    1886   }
    1887   if (jobj2 != NULL) {
    1888     if (jobj2->escape_state() == PointsToNode::NoEscape) {
    1889       Node* obj = jobj2->ideal_node();
    1890       // Comparing not escaping allocation.
    1891       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
    1892           !ptn1->points_to(jobj2)) {
    1893         return _pcmp_neq; // This includes nullness check.
    1894       }
    1895     }
    1896   }
    1897   if (jobj1 != NULL && jobj1 != phantom_obj &&
    1898       jobj2 != NULL && jobj2 != phantom_obj &&
    1899       jobj1->ideal_node()->is_Con() &&
    1900       jobj2->ideal_node()->is_Con()) {
    1901     // Klass or String constants compare. Need to be careful with
    1902     // compressed pointers - compare types of ConN and ConP instead of nodes.
    1903     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
    1904     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
    1905     if (t1->make_ptr() == t2->make_ptr()) {
    1906       return _pcmp_eq;
    1907     } else {
    1908       return _pcmp_neq;
    1909     }
    1910   }
    1911   if (ptn1->meet(ptn2)) {
    1912     return NULL; // Sets are not disjoint
    1913   }
    1914
    1915   // Sets are disjoint.
    1916   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
    1917   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
    1918   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
    1919   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
    1920   if (set1_has_unknown_ptr && set2_has_null_ptr ||
    1921       set2_has_unknown_ptr && set1_has_null_ptr) {
    1922     // Check nullness of unknown object.
    1923     return NULL;
    1924   }
    1925
    1926   // Disjointness by itself is not sufficient since
    1927   // alias analysis is not complete for escaped objects.
    1928   // Disjoint sets are definitely unrelated only when
    1929   // at least one set has only not escaping allocations.
    1930   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
    1931     if (ptn1->non_escaping_allocation()) {
    1932       return _pcmp_neq;
    1933     }
    1934   }
    1935   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
    1936     if (ptn2->non_escaping_allocation()) {
    1937       return _pcmp_neq;
    1938     }
    1939   }
    1940   return NULL;
    1941 }
    1942
    1943 // Connection Graph constuction functions.
    1944
    1945 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
    1946   PointsToNode* ptadr = _nodes.at(n->_idx);
    1947   if (ptadr != NULL) {
    1948     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
    1949     return;
    1950   }
    1951   Compile* C = _compile;
    1952   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
    1953   _nodes.at_put(n->_idx, ptadr);
    1954 }
    1955
    1956 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
    1957   PointsToNode* ptadr = _nodes.at(n->_idx);
    1958   if (ptadr != NULL) {
    1959     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
    1960     return;
    1961   }
    1962   Compile* C = _compile;
    1963   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
    1964   _nodes.at_put(n->_idx, ptadr);
    1965 }
    1966
    1967 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
    1968   PointsToNode* ptadr = _nodes.at(n->_idx);
    1969   if (ptadr != NULL) {
    1970     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
    1971     return;
    1972   }
    1973   bool unsafe = false;
    1974   bool is_oop = is_oop_field(n, offset, &unsafe);
    1975   if (unsafe) {
    1976     es = PointsToNode::GlobalEscape;
    1977   }
    1978   Compile* C = _compile;
    1979   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
    1980   _nodes.at_put(n->_idx, field);
    1981 }
    1982
    1983 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
    1984                                     PointsToNode* src, PointsToNode* dst) {
    1985   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
    1986   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
    1987   PointsToNode* ptadr = _nodes.at(n->_idx);
    1988   if (ptadr != NULL) {
    1989     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
    1990     return;
    1991   }
    1992   Compile* C = _compile;
    1993   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
    1994   _nodes.at_put(n->_idx, ptadr);
    1995   // Add edge from arraycopy node to source object.
    1996   (void)add_edge(ptadr, src);
    1997   src->set_arraycopy_src();
    1998   // Add edge from destination object to arraycopy node.
    1999   (void)add_edge(dst, ptadr);
    2000   dst->set_arraycopy_dst();
    2001 }
    2002
    2003 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
    2004   const Type* adr_type = n->as_AddP()->bottom_type();
    2005   BasicType bt = T_INT;
    2006   if (offset == Type::OffsetBot) {
    2007     // Check only oop fields.
    2008     if (!adr_type->isa_aryptr() ||
    2009         (adr_type->isa_aryptr()->klass() == NULL) ||
    2010          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
    2011       // OffsetBot is used to reference array's element. Ignore first AddP.
    2012       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
    2013         bt = T_OBJECT;
    2014       }
    2015     }
    2016   } else if (offset != oopDesc::klass_offset_in_bytes()) {
    2017     if (adr_type->isa_instptr()) {
    2018       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
    2019       if (field != NULL) {
    2020         bt = field->layout_type();
    2021       } else {
    2022         // Check for unsafe oop field access
    2023         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
    2024           bt = T_OBJECT;
    2025           (*unsafe) = true;
    2026         }
    2027       }
    2028     } else if (adr_type->isa_aryptr()) {
    2029       if (offset == arrayOopDesc::length_offset_in_bytes()) {
    2030         // Ignore array length load.
    2031       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
    2032         // Ignore first AddP.
    2033       } else {
    2034         const Type* elemtype = adr_type->isa_aryptr()->elem();
    2035         bt = elemtype->array_element_basic_type();
    2036       }
    2037     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
    2038       // Allocation initialization, ThreadLocal field access, unsafe access
    2039       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
    2040         bt = T_OBJECT;
    2041       }
    2042     }
    2043   }
    2044   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
    2045 }
    2046
    2047 // Returns unique pointed java object or NULL.
    2048 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
    2049   assert(!_collecting, "should not call when contructed graph");
    2050   // If the node was created after the escape computation we can't answer.
    2051   uint idx = n->_idx;
    2052   if (idx >= nodes_size()) {
    2053     return NULL;
    2054   }
    2055   PointsToNode* ptn = ptnode_adr(idx);
    2056   if (ptn->is_JavaObject()) {
    2057     return ptn->as_JavaObject();
    2058   }
    2059   assert(ptn->is_LocalVar(), "sanity");
    2060   // Check all java objects it points to.
    2061   JavaObjectNode* jobj = NULL;
    2062   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
    2063     PointsToNode* e = i.get();
    2064     if (e->is_JavaObject()) {
    2065       if (jobj == NULL) {
    2066         jobj = e->as_JavaObject();
    2067       } else if (jobj != e) {
    2068         return NULL;
    2069       }
    2070     }
    2071   }
    2072   return jobj;
    2073 }
    2074
    2075 // Return true if this node points only to non-escaping allocations.
    2076 bool PointsToNode::non_escaping_allocation() {
    2077   if (is_JavaObject()) {
    2078     Node* n = ideal_node();
    2079     if (n->is_Allocate() || n->is_CallStaticJava()) {
    2080       return (escape_state() == PointsToNode::NoEscape);
    2081     } else {
    2082       return false;
    2083     }
    2084   }
    2085   assert(is_LocalVar(), "sanity");
    2086   // Check all java objects it points to.
    2087   for (EdgeIterator i(this); i.has_next(); i.next()) {
    2088     PointsToNode* e = i.get();
    2089     if (e->is_JavaObject()) {
    2090       Node* n = e->ideal_node();
    2091       if ((e->escape_state() != PointsToNode::NoEscape) ||
    2092           !(n->is_Allocate() || n->is_CallStaticJava())) {
    2093         return false;
    2094       }
    2095     }
    2096   }
    2097   return true;
    2098 }
    2099
    2100 // Return true if we know the node does not escape globally.
    2101 bool ConnectionGraph::not_global_escape(Node *n) {
    2102   assert(!_collecting, "should not call during graph construction");
    2103   // If the node was created after the escape computation we can't answer.
    2104   uint idx = n->_idx;
    2105   if (idx >= nodes_size()) {
    2106     return false;
    2107   }
    2108   PointsToNode* ptn = ptnode_adr(idx);
    2109   PointsToNode::EscapeState es = ptn->escape_state();
    2110   // If we have already computed a value, return it.
    2111   if (es >= PointsToNode::GlobalEscape)
    2112     return false;
    2113   if (ptn->is_JavaObject()) {
    2114     return true; // (es < PointsToNode::GlobalEscape);
    2115   }
    2116   assert(ptn->is_LocalVar(), "sanity");
    2117   // Check all java objects it points to.
    2118   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
    2119     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
    2120       return false;
    2121   }
    2122   return true;
    2123 }
    2124
    2125
    2126 // Helper functions
    2127
    2128 // Return true if this node points to specified node or nodes it points to.
    2129 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
    2130   if (is_JavaObject()) {
    2131     return (this == ptn);
    2132   }
    2133   assert(is_LocalVar() || is_Field(), "sanity");
    2134   for (EdgeIterator i(this); i.has_next(); i.next()) {
    2135     if (i.get() == ptn)
    2136       return true;
    2137   }
    2138   return false;
    2139 }
    2140
    2141 // Return true if one node points to an other.
    2142 bool PointsToNode::meet(PointsToNode* ptn) {
    2143   if (this == ptn) {
    2144     return true;
    2145   } else if (ptn->is_JavaObject()) {
    2146     return this->points_to(ptn->as_JavaObject());
    2147   } else if (this->is_JavaObject()) {
    2148     return ptn->points_to(this->as_JavaObject());
    2149   }
    2150   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
    2151   int ptn_count =  ptn->edge_count();
    2152   for (EdgeIterator i(this); i.has_next(); i.next()) {
    2153     PointsToNode* this_e = i.get();
    2154     for (int j = 0; j < ptn_count; j++) {
    2155       if (this_e == ptn->edge(j))
    2156         return true;
    2157     }
    2158   }
    2159   return false;
    2160 }
    2161
    2162 #ifdef ASSERT
    2163 // Return true if bases point to this java object.
    2164 bool FieldNode::has_base(JavaObjectNode* jobj) const {
    2165   for (BaseIterator i(this); i.has_next(); i.next()) {
    2166     if (i.get() == jobj)
    2167       return true;
    2168   }
    2169   return false;
    2170 }
    2171 #endif
    2172
    2173 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
    2174   const Type *adr_type = phase->type(adr);
    2175   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
    2176       adr->in(AddPNode::Address)->is_Proj() &&
    2177       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
    2178     // We are computing a raw address for a store captured by an Initialize
    2179     // compute an appropriate address type. AddP cases #3 and #5 (see below).
    2180     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
    2181     assert(offs != Type::OffsetBot ||
    2182            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
    2183            "offset must be a constant or it is initialization of array");
    2184     return offs;
    2185   }
    2186   const TypePtr *t_ptr = adr_type->isa_ptr();
    2187   assert(t_ptr != NULL, "must be a pointer type");
    2188   return t_ptr->offset();
    2189 }
    2190
    2191 Node* ConnectionGraph::get_addp_base(Node *addp) {
    2192   assert(addp->is_AddP(), "must be AddP");
    2193   //
    2194   // AddP cases for Base and Address inputs:
    2195   // case #1. Direct object's field reference:
    2196   //     Allocate
    2197   //       |
    2198   //     Proj #5 ( oop result )
    2199   //       |
    2200   //     CheckCastPP (cast to instance type)
    2201   //      | |
    2202   //     AddP  ( base == address )
    2203   //
    2204   // case #2. Indirect object's field reference:
    2205   //      Phi
    2206   //       |
    2207   //     CastPP (cast to instance type)
    2208   //      | |
    2209   //     AddP  ( base == address )
    2210   //
    2211   // case #3. Raw object's field reference for Initialize node:
    2212   //      Allocate
    2213   //        |
    2214   //      Proj #5 ( oop result )
    2215   //  top   |
    2216   //     \  |
    2217   //     AddP  ( base == top )
    2218   //
    2219   // case #4. Array's element reference:
    2220   //   {CheckCastPP | CastPP}
    2221   //     |  | |
    2222   //     |  AddP ( array's element offset )
    2223   //     |  |
    2224   //     AddP ( array's offset )
    2225   //
    2226   // case #5. Raw object's field reference for arraycopy stub call:
    2227   //          The inline_native_clone() case when the arraycopy stub is called
    2228   //          after the allocation before Initialize and CheckCastPP nodes.
    2229   //      Allocate
    2230   //        |
    2231   //      Proj #5 ( oop result )
    2232   //       | |
    2233   //       AddP  ( base == address )
    2234   //
    2235   // case #6. Constant Pool, ThreadLocal, CastX2P or
    2236   //          Raw object's field reference:
    2237   //      {ConP, ThreadLocal, CastX2P, raw Load}
    2238   //  top   |
    2239   //     \  |
    2240   //     AddP  ( base == top )
    2241   //
    2242   // case #7. Klass's field reference.
    2243   //      LoadKlass
    2244   //       | |
    2245   //       AddP  ( base == address )
    2246   //
    2247   // case #8. narrow Klass's field reference.
    2248   //      LoadNKlass
    2249   //       |
    2250   //      DecodeN
    2251   //       | |
    2252   //       AddP  ( base == address )
    2253   //
    2254   Node *base = addp->in(AddPNode::Base);
    2255   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
    2256     base = addp->in(AddPNode::Address);
    2257     while (base->is_AddP()) {
    2258       // Case #6 (unsafe access) may have several chained AddP nodes.
    2259       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
    2260       base = base->in(AddPNode::Address);
    2261     }
    2262     Node* uncast_base = base->uncast();
    2263     int opcode = uncast_base->Opcode();
    2264     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
    2265            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
    2266            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
    2267            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
    2268   }
    2269   return base;
    2270 }
    2271
    2272 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
    2273   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
    2274   Node* addp2 = addp->raw_out(0);
    2275   if (addp->outcnt() == 1 && addp2->is_AddP() &&
    2276       addp2->in(AddPNode::Base) == n &&
    2277       addp2->in(AddPNode::Address) == addp) {
    2278     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
    2279     //
    2280     // Find array's offset to push it on worklist first and
    2281     // as result process an array's element offset first (pushed second)
    2282     // to avoid CastPP for the array's offset.
    2283     // Otherwise the inserted CastPP (LocalVar) will point to what
    2284     // the AddP (Field) points to. Which would be wrong since
    2285     // the algorithm expects the CastPP has the same point as
    2286     // as AddP's base CheckCastPP (LocalVar).
    2287     //
    2288     //    ArrayAllocation
    2289     //     |
    2290     //    CheckCastPP
    2291     //     |
    2292     //    memProj (from ArrayAllocation CheckCastPP)
    2293     //     |  ||
    2294     //     |  ||   Int (element index)
    2295     //     |  ||    |   ConI (log(element size))
    2296     //     |  ||    |   /
    2297     //     |  ||   LShift
    2298     //     |  ||  /
    2299     //     |  AddP (array's element offset)
    2300     //     |  |
    2301     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
    2302     //     | / /
    2303     //     AddP (array's offset)
    2304     //      |
    2305     //     Load/Store (memory operation on array's element)
    2306     //
    2307     return addp2;
    2308   }
    2309   return NULL;
    2310 }
    2311
    2312 //
    2313 // Adjust the type and inputs of an AddP which computes the
    2314 // address of a field of an instance
    2315 //
    2316 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
    2317   PhaseGVN* igvn = _igvn;
    2318   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
    2319   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
    2320   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
    2321   if (t == NULL) {
    2322     // We are computing a raw address for a store captured by an Initialize
    2323     // compute an appropriate address type (cases #3 and #5).
    2324     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
    2325     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
    2326     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
    2327     assert(offs != Type::OffsetBot, "offset must be a constant");
    2328     t = base_t->add_offset(offs)->is_oopptr();
    2329   }
    2330   int inst_id =  base_t->instance_id();
    2331   assert(!t->is_known_instance() || t->instance_id() == inst_id,
    2332                              "old type must be non-instance or match new type");
    2333
    2334   // The type 't' could be subclass of 'base_t'.
    2335   // As result t->offset() could be large then base_t's size and it will
    2336   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
    2337   // constructor verifies correctness of the offset.
    2338   //
    2339   // It could happened on subclass's branch (from the type profiling
    2340   // inlining) which was not eliminated during parsing since the exactness
    2341   // of the allocation type was not propagated to the subclass type check.
    2342   //
    2343   // Or the type 't' could be not related to 'base_t' at all.
    2344   // It could happened when CHA type is different from MDO type on a dead path
    2345   // (for example, from instanceof check) which is not collapsed during parsing.
    2346   //
    2347   // Do nothing for such AddP node and don't process its users since
    2348   // this code branch will go away.
    2349   //
    2350   if (!t->is_known_instance() &&
    2351       !base_t->klass()->is_subtype_of(t->klass())) {
    2352      return false; // bail out
    2353   }
    2354   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
    2355   // Do NOT remove the next line: ensure a new alias index is allocated
    2356   // for the instance type. Note: C++ will not remove it since the call
    2357   // has side effect.
    2358   int alias_idx = _compile->get_alias_index(tinst);
    2359   igvn->set_type(addp, tinst);
    2360   // record the allocation in the node map
    2361   set_map(addp, get_map(base->_idx));
    2362   // Set addp's Base and Address to 'base'.
    2363   Node *abase = addp->in(AddPNode::Base);
    2364   Node *adr   = addp->in(AddPNode::Address);
    2365   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
    2366       adr->in(0)->_idx == (uint)inst_id) {
    2367     // Skip AddP cases #3 and #5.
    2368   } else {
    2369     assert(!abase->is_top(), "sanity"); // AddP case #3
    2370     if (abase != base) {
    2371       igvn->hash_delete(addp);
    2372       addp->set_req(AddPNode::Base, base);
    2373       if (abase == adr) {
    2374         addp->set_req(AddPNode::Address, base);
    2375       } else {
    2376         // AddP case #4 (adr is array's element offset AddP node)
    2377 #ifdef ASSERT
    2378         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
    2379         assert(adr->is_AddP() && atype != NULL &&
    2380                atype->instance_id() == inst_id, "array's element offset should be processed first");
    2381 #endif
    2382       }
    2383       igvn->hash_insert(addp);
    2384     }
    2385   }
    2386   // Put on IGVN worklist since at least addp's type was changed above.
    2387   record_for_optimizer(addp);
    2388   return true;
    2389 }
    2390
    2391 //
    2392 // Create a new version of orig_phi if necessary. Returns either the newly
    2393 // created phi or an existing phi.  Sets create_new to indicate whether a new
    2394 // phi was created.  Cache the last newly created phi in the node map.
    2395 //
    2396 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
    2397   Compile *C = _compile;
    2398   PhaseGVN* igvn = _igvn;
    2399   new_created = false;
    2400   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
    2401   // nothing to do if orig_phi is bottom memory or matches alias_idx
    2402   if (phi_alias_idx == alias_idx) {
    2403     return orig_phi;
    2404   }
    2405   // Have we recently created a Phi for this alias index?
    2406   PhiNode *result = get_map_phi(orig_phi->_idx);
    2407   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
    2408     return result;
    2409   }
    2410   // Previous check may fail when the same wide memory Phi was split into Phis
    2411   // for different memory slices. Search all Phis for this region.
    2412   if (result != NULL) {
    2413     Node* region = orig_phi->in(0);
    2414     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
    2415       Node* phi = region->fast_out(i);
    2416       if (phi->is_Phi() &&
    2417           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
    2418         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
    2419         return phi->as_Phi();
    2420       }
    2421     }
    2422   }
    2423   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
    2424     if (C->do_escape_analysis() == true && !C->failing()) {
    2425       // Retry compilation without escape analysis.
    2426       // If this is the first failure, the sentinel string will "stick"
    2427       // to the Compile object, and the C2Compiler will see it and retry.
    2428       C->record_failure(C2Compiler::retry_no_escape_analysis());
    2429     }
    2430     return NULL;
    2431   }
    2432   orig_phi_worklist.append_if_missing(orig_phi);
    2433   const TypePtr *atype = C->get_adr_type(alias_idx);
    2434   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
    2435   C->copy_node_notes_to(result, orig_phi);
    2436   igvn->set_type(result, result->bottom_type());
    2437   record_for_optimizer(result);
    2438   set_map(orig_phi, result);
    2439   new_created = true;
    2440   return result;
    2441 }
    2442
    2443 //
    2444 // Return a new version of Memory Phi "orig_phi" with the inputs having the
    2445 // specified alias index.
    2446 //
    2447 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
    2448   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
    2449   Compile *C = _compile;
    2450   PhaseGVN* igvn = _igvn;
    2451   bool new_phi_created;
    2452   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
    2453   if (!new_phi_created) {
    2454     return result;
    2455   }
    2456   GrowableArray<PhiNode *>  phi_list;
    2457   GrowableArray<uint>  cur_input;
    2458   PhiNode *phi = orig_phi;
    2459   uint idx = 1;
    2460   bool finished = false;
    2461   while(!finished) {
    2462     while (idx < phi->req()) {
    2463       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
    2464       if (mem != NULL && mem->is_Phi()) {
    2465         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
    2466         if (new_phi_created) {
    2467           // found an phi for which we created a new split, push current one on worklist and begin
    2468           // processing new one
    2469           phi_list.push(phi);
    2470           cur_input.push(idx);
    2471           phi = mem->as_Phi();
    2472           result = newphi;
    2473           idx = 1;
    2474           continue;
    2475         } else {
    2476           mem = newphi;
    2477         }
    2478       }
    2479       if (C->failing()) {
    2480         return NULL;
    2481       }
    2482       result->set_req(idx++, mem);
    2483     }
    2484 #ifdef ASSERT
    2485     // verify that the new Phi has an input for each input of the original
    2486     assert( phi->req() == result->req(), "must have same number of inputs.");
    2487     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
    2488 #endif
    2489     // Check if all new phi's inputs have specified alias index.
    2490     // Otherwise use old phi.
    2491     for (uint i = 1; i < phi->req(); i++) {
    2492       Node* in = result->in(i);
    2493       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
    2494     }
    2495     // we have finished processing a Phi, see if there are any more to do
    2496     finished = (phi_list.length() == 0 );
    2497     if (!finished) {
    2498       phi = phi_list.pop();
    2499       idx = cur_input.pop();
    2500       PhiNode *prev_result = get_map_phi(phi->_idx);
    2501       prev_result->set_req(idx++, result);
    2502       result = prev_result;
    2503     }
    2504   }
    2505   return result;
    2506 }
    2507
    2508 //
    2509 // The next methods are derived from methods in MemNode.
    2510 //
    2511 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
    2512   Node *mem = mmem;
    2513   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
    2514   // means an array I have not precisely typed yet.  Do not do any
    2515   // alias stuff with it any time soon.
    2516   if (toop->base() != Type::AnyPtr &&
    2517       !(toop->klass() != NULL &&
    2518         toop->klass()->is_java_lang_Object() &&
    2519         toop->offset() == Type::OffsetBot)) {
    2520     mem = mmem->memory_at(alias_idx);
    2521     // Update input if it is progress over what we have now
    2522   }
    2523   return mem;
    2524 }
    2525
    2526 //
    2527 // Move memory users to their memory slices.
    2528 //
    2529 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
    2530   Compile* C = _compile;
    2531   PhaseGVN* igvn = _igvn;
    2532   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
    2533   assert(tp != NULL, "ptr type");
    2534   int alias_idx = C->get_alias_index(tp);
    2535   int general_idx = C->get_general_index(alias_idx);
    2536
    2537   // Move users first
    2538   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
    2539     Node* use = n->fast_out(i);
    2540     if (use->is_MergeMem()) {
    2541       MergeMemNode* mmem = use->as_MergeMem();
    2542       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
    2543       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
    2544         continue; // Nothing to do
    2545       }
    2546       // Replace previous general reference to mem node.
    2547       uint orig_uniq = C->unique();
    2548       Node* m = find_inst_mem(n, general_idx, orig_phis);
    2549       assert(orig_uniq == C->unique(), "no new nodes");
    2550       mmem->set_memory_at(general_idx, m);
    2551       --imax;
    2552       --i;
    2553     } else if (use->is_MemBar()) {
    2554       assert(!use->is_Initialize(), "initializing stores should not be moved");
    2555       if (use->req() > MemBarNode::Precedent &&
    2556           use->in(MemBarNode::Precedent) == n) {
    2557         // Don't move related membars.
    2558         record_for_optimizer(use);
    2559         continue;
    2560       }
    2561       tp = use->as_MemBar()->adr_type()->isa_ptr();
    2562       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
    2563           alias_idx == general_idx) {
    2564         continue; // Nothing to do
    2565       }
    2566       // Move to general memory slice.
    2567       uint orig_uniq = C->unique();
    2568       Node* m = find_inst_mem(n, general_idx, orig_phis);
    2569       assert(orig_uniq == C->unique(), "no new nodes");
    2570       igvn->hash_delete(use);
    2571       imax -= use->replace_edge(n, m);
    2572       igvn->hash_insert(use);
    2573       record_for_optimizer(use);
    2574       --i;
    2575 #ifdef ASSERT
    2576     } else if (use->is_Mem()) {
    2577       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
    2578         // Don't move related cardmark.
    2579         continue;
    2580       }
    2581       // Memory nodes should have new memory input.
    2582       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
    2583       assert(tp != NULL, "ptr type");
    2584       int idx = C->get_alias_index(tp);
    2585       assert(get_map(use->_idx) != NULL || idx == alias_idx,
    2586              "Following memory nodes should have new memory input or be on the same memory slice");
    2587     } else if (use->is_Phi()) {
    2588       // Phi nodes should be split and moved already.
    2589       tp = use->as_Phi()->adr_type()->isa_ptr();
    2590       assert(tp != NULL, "ptr type");
    2591       int idx = C->get_alias_index(tp);
    2592       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
    2593     } else {
    2594       use->dump();
    2595       assert(false, "should not be here");
    2596 #endif
    2597     }
    2598   }
    2599 }
    2600
    2601 //
    2602 // Search memory chain of "mem" to find a MemNode whose address
    2603 // is the specified alias index.
    2604 //
    2605 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
    2606   if (orig_mem == NULL)
    2607     return orig_mem;
    2608   Compile* C = _compile;
    2609   PhaseGVN* igvn = _igvn;
    2610   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
    2611   bool is_instance = (toop != NULL) && toop->is_known_instance();
    2612   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
    2613   Node *prev = NULL;
    2614   Node *result = orig_mem;
    2615   while (prev != result) {
    2616     prev = result;
    2617     if (result == start_mem)
    2618       break;  // hit one of our sentinels
    2619     if (result->is_Mem()) {
    2620       const Type *at = igvn->type(result->in(MemNode::Address));
    2621       if (at == Type::TOP)
    2622         break; // Dead
    2623       assert (at->isa_ptr() != NULL, "pointer type required.");
    2624       int idx = C->get_alias_index(at->is_ptr());
    2625       if (idx == alias_idx)
    2626         break; // Found
    2627       if (!is_instance && (at->isa_oopptr() == NULL ||
    2628                            !at->is_oopptr()->is_known_instance())) {
    2629         break; // Do not skip store to general memory slice.
    2630       }
    2631       result = result->in(MemNode::Memory);
    2632     }
    2633     if (!is_instance)
    2634       continue;  // don't search further for non-instance types
    2635     // skip over a call which does not affect this memory slice
    2636     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
    2637       Node *proj_in = result->in(0);
    2638       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
    2639         break;  // hit one of our sentinels
    2640       } else if (proj_in->is_Call()) {
    2641         CallNode *call = proj_in->as_Call();
    2642         if (!call->may_modify(toop, igvn)) {
    2643           result = call->in(TypeFunc::Memory);
    2644         }
    2645       } else if (proj_in->is_Initialize()) {
    2646         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
    2647         // Stop if this is the initialization for the object instance which
    2648         // which contains this memory slice, otherwise skip over it.
    2649         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
    2650           result = proj_in->in(TypeFunc::Memory);
    2651         }
    2652       } else if (proj_in->is_MemBar()) {
    2653         result = proj_in->in(TypeFunc::Memory);
    2654       }
    2655     } else if (result->is_MergeMem()) {
    2656       MergeMemNode *mmem = result->as_MergeMem();
    2657       result = step_through_mergemem(mmem, alias_idx, toop);
    2658       if (result == mmem->base_memory()) {
    2659         // Didn't find instance memory, search through general slice recursively.
    2660         result = mmem->memory_at(C->get_general_index(alias_idx));
    2661         result = find_inst_mem(result, alias_idx, orig_phis);
    2662         if (C->failing()) {
    2663           return NULL;
    2664         }
    2665         mmem->set_memory_at(alias_idx, result);
    2666       }
    2667     } else if (result->is_Phi() &&
    2668                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
    2669       Node *un = result->as_Phi()->unique_input(igvn);
    2670       if (un != NULL) {
    2671         orig_phis.append_if_missing(result->as_Phi());
    2672         result = un;
    2673       } else {
    2674         break;
    2675       }
    2676     } else if (result->is_ClearArray()) {
    2677       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
    2678         // Can not bypass initialization of the instance
    2679         // we are looking for.
    2680         break;
    2681       }
    2682       // Otherwise skip it (the call updated 'result' value).
    2683     } else if (result->Opcode() == Op_SCMemProj) {
    2684       Node* mem = result->in(0);
    2685       Node* adr = NULL;
    2686       if (mem->is_LoadStore()) {
    2687         adr = mem->in(MemNode::Address);
    2688       } else {
    2689         assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
    2690         adr = mem->in(3); // Memory edge corresponds to destination array
    2691       }
    2692       const Type *at = igvn->type(adr);
    2693       if (at != Type::TOP) {
    2694         assert (at->isa_ptr() != NULL, "pointer type required.");
    2695         int idx = C->get_alias_index(at->is_ptr());
    2696         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
    2697         break;
    2698       }
    2699       result = mem->in(MemNode::Memory);
    2700     }
    2701   }
    2702   if (result->is_Phi()) {
    2703     PhiNode *mphi = result->as_Phi();
    2704     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
    2705     const TypePtr *t = mphi->adr_type();
    2706     if (!is_instance) {
    2707       // Push all non-instance Phis on the orig_phis worklist to update inputs
    2708       // during Phase 4 if needed.
    2709       orig_phis.append_if_missing(mphi);
    2710     } else if (C->get_alias_index(t) != alias_idx) {
    2711       // Create a new Phi with the specified alias index type.
    2712       result = split_memory_phi(mphi, alias_idx, orig_phis);
    2713     }
    2714   }
    2715   // the result is either MemNode, PhiNode, InitializeNode.
    2716   return result;
    2717 }
    2718
    2719 //
    2720 //  Convert the types of unescaped object to instance types where possible,
    2721 //  propagate the new type information through the graph, and update memory
    2722 //  edges and MergeMem inputs to reflect the new type.
    2723 //
    2724 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
    2725 //  The processing is done in 4 phases:
    2726 //
    2727 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
    2728 //            types for the CheckCastPP for allocations where possible.
    2729 //            Propagate the the new types through users as follows:
    2730 //               casts and Phi:  push users on alloc_worklist
    2731 //               AddP:  cast Base and Address inputs to the instance type
    2732 //                      push any AddP users on alloc_worklist and push any memnode
    2733 //                      users onto memnode_worklist.
    2734 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
    2735 //            search the Memory chain for a store with the appropriate type
    2736 //            address type.  If a Phi is found, create a new version with
    2737 //            the appropriate memory slices from each of the Phi inputs.
    2738 //            For stores, process the users as follows:
    2739 //               MemNode:  push on memnode_worklist
    2740 //               MergeMem: push on mergemem_worklist
    2741 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
    2742 //            moving the first node encountered of each  instance type to the
    2743 //            the input corresponding to its alias index.
    2744 //            appropriate memory slice.
    2745 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
    2746 //
    2747 // In the following example, the CheckCastPP nodes are the cast of allocation
    2748 // results and the allocation of node 29 is unescaped and eligible to be an
    2749 // instance type.
    2750 //
    2751 // We start with:
    2752 //
    2753 //     7 Parm #memory
    2754 //    10  ConI  "12"
    2755 //    19  CheckCastPP   "Foo"
    2756 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
    2757 //    29  CheckCastPP   "Foo"
    2758 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
    2759 //
    2760 //    40  StoreP  25   7  20   ... alias_index=4
    2761 //    50  StoreP  35  40  30   ... alias_index=4
    2762 //    60  StoreP  45  50  20   ... alias_index=4
    2763 //    70  LoadP    _  60  30   ... alias_index=4
    2764 //    80  Phi     75  50  60   Memory alias_index=4
    2765 //    90  LoadP    _  80  30   ... alias_index=4
    2766 //   100  LoadP    _  80  20   ... alias_index=4
    2767 //
    2768 //
    2769 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
    2770 // and creating a new alias index for node 30.  This gives:
    2771 //
    2772 //     7 Parm #memory
    2773 //    10  ConI  "12"
    2774 //    19  CheckCastPP   "Foo"
    2775 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
    2776 //    29  CheckCastPP   "Foo"  iid=24
    2777 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
    2778 //
    2779 //    40  StoreP  25   7  20   ... alias_index=4
    2780 //    50  StoreP  35  40  30   ... alias_index=6
    2781 //    60  StoreP  45  50  20   ... alias_index=4
    2782 //    70  LoadP    _  60  30   ... alias_index=6
    2783 //    80  Phi     75  50  60   Memory alias_index=4
    2784 //    90  LoadP    _  80  30   ... alias_index=6
    2785 //   100  LoadP    _  80  20   ... alias_index=4
    2786 //
    2787 // In phase 2, new memory inputs are computed for the loads and stores,
    2788 // And a new version of the phi is created.  In phase 4, the inputs to
    2789 // node 80 are updated and then the memory nodes are updated with the
    2790 // values computed in phase 2.  This results in:
    2791 //
    2792 //     7 Parm #memory
    2793 //    10  ConI  "12"
    2794 //    19  CheckCastPP   "Foo"
    2795 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
    2796 //    29  CheckCastPP   "Foo"  iid=24
    2797 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
    2798 //
    2799 //    40  StoreP  25  7   20   ... alias_index=4
    2800 //    50  StoreP  35  7   30   ... alias_index=6
    2801 //    60  StoreP  45  40  20   ... alias_index=4
    2802 //    70  LoadP    _  50  30   ... alias_index=6
    2803 //    80  Phi     75  40  60   Memory alias_index=4
    2804 //   120  Phi     75  50  50   Memory alias_index=6
    2805 //    90  LoadP    _ 120  30   ... alias_index=6
    2806 //   100  LoadP    _  80  20   ... alias_index=4
    2807 //
    2808 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {
    2809   GrowableArray<Node *>  memnode_worklist;
    2810   GrowableArray<PhiNode *>  orig_phis;
    2811   PhaseIterGVN  *igvn = _igvn;
    2812   uint new_index_start = (uint) _compile->num_alias_types();
    2813   Arena* arena = Thread::current()->resource_area();
    2814   VectorSet visited(arena);
    2815   ideal_nodes.clear(); // Reset for use with set_map/get_map.
    2816   uint unique_old = _compile->unique();
    2817
    2818   //  Phase 1:  Process possible allocations from alloc_worklist.
    2819   //  Create instance types for the CheckCastPP for allocations where possible.
    2820   //
    2821   // (Note: don't forget to change the order of the second AddP node on
    2822   //  the alloc_worklist if the order of the worklist processing is changed,
    2823   //  see the comment in find_second_addp().)
    2824   //
    2825   while (alloc_worklist.length() != 0) {
    2826     Node *n = alloc_worklist.pop();
    2827     uint ni = n->_idx;
    2828     if (n->is_Call()) {
    2829       CallNode *alloc = n->as_Call();
    2830       // copy escape information to call node
    2831       PointsToNode* ptn = ptnode_adr(alloc->_idx);
    2832       PointsToNode::EscapeState es = ptn->escape_state();
    2833       // We have an allocation or call which returns a Java object,
    2834       // see if it is unescaped.
    2835       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
    2836         continue;
    2837       // Find CheckCastPP for the allocate or for the return value of a call
    2838       n = alloc->result_cast();
    2839       if (n == NULL) {            // No uses except Initialize node
    2840         if (alloc->is_Allocate()) {
    2841           // Set the scalar_replaceable flag for allocation
    2842           // so it could be eliminated if it has no uses.
    2843           alloc->as_Allocate()->_is_scalar_replaceable = true;
    2844         }
    2845         if (alloc->is_CallStaticJava()) {
    2846           // Set the scalar_replaceable flag for boxing method
    2847           // so it could be eliminated if it has no uses.
    2848           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
    2849         }
    2850         continue;
    2851       }
    2852       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
    2853         assert(!alloc->is_Allocate(), "allocation should have unique type");
    2854         continue;
    2855       }
    2856
    2857       // The inline code for Object.clone() casts the allocation result to
    2858       // java.lang.Object and then to the actual type of the allocated
    2859       // object. Detect this case and use the second cast.
    2860       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
    2861       // the allocation result is cast to java.lang.Object and then
    2862       // to the actual Array type.
    2863       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
    2864           && (alloc->is_AllocateArray() ||
    2865               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
    2866         Node *cast2 = NULL;
    2867         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
    2868           Node *use = n->fast_out(i);
    2869           if (use->is_CheckCastPP()) {
    2870             cast2 = use;
    2871             break;
    2872           }
    2873         }
    2874         if (cast2 != NULL) {
    2875           n = cast2;
    2876         } else {
    2877           // Non-scalar replaceable if the allocation type is unknown statically
    2878           // (reflection allocation), the object can't be restored during
    2879           // deoptimization without precise type.
    2880           continue;
    2881         }
    2882       }
    2883
    2884       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
    2885       if (t == NULL)
    2886         continue;  // not a TypeOopPtr
    2887       if (!t->klass_is_exact())
    2888         continue; // not an unique type
    2889
    2890       if (alloc->is_Allocate()) {
    2891         // Set the scalar_replaceable flag for allocation
    2892         // so it could be eliminated.
    2893         alloc->as_Allocate()->_is_scalar_replaceable = true;
    2894       }
    2895       if (alloc->is_CallStaticJava()) {
    2896         // Set the scalar_replaceable flag for boxing method
    2897         // so it could be eliminated.
    2898         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
    2899       }
    2900       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
    2901       // in order for an object to be scalar-replaceable, it must be:
    2902       //   - a direct allocation (not a call returning an object)
    2903       //   - non-escaping
    2904       //   - eligible to be a unique type
    2905       //   - not determined to be ineligible by escape analysis
    2906       set_map(alloc, n);
    2907       set_map(n, alloc);
    2908       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
    2909       igvn->hash_delete(n);
    2910       igvn->set_type(n,  tinst);
    2911       n->raise_bottom_type(tinst);
    2912       igvn->hash_insert(n);
    2913       record_for_optimizer(n);
    2914       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
    2915
    2916         // First, put on the worklist all Field edges from Connection Graph
    2917         // which is more accurate then putting immediate users from Ideal Graph.
    2918         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
    2919           PointsToNode* tgt = e.get();
    2920           Node* use = tgt->ideal_node();
    2921           assert(tgt->is_Field() && use->is_AddP(),
    2922                  "only AddP nodes are Field edges in CG");
    2923           if (use->outcnt() > 0) { // Don't process dead nodes
    2924             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
    2925             if (addp2 != NULL) {
    2926               assert(alloc->is_AllocateArray(),"array allocation was expected");
    2927               alloc_worklist.append_if_missing(addp2);
    2928             }
    2929             alloc_worklist.append_if_missing(use);
    2930           }
    2931         }
    2932
    2933         // An allocation may have an Initialize which has raw stores. Scan
    2934         // the users of the raw allocation result and push AddP users
    2935         // on alloc_worklist.
    2936         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
    2937         assert (raw_result != NULL, "must have an allocation result");
    2938         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
    2939           Node *use = raw_result->fast_out(i);
    2940           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
    2941             Node* addp2 = find_second_addp(use, raw_result);
    2942             if (addp2 != NULL) {
    2943               assert(alloc->is_AllocateArray(),"array allocation was expected");
    2944               alloc_worklist.append_if_missing(addp2);
    2945             }
    2946             alloc_worklist.append_if_missing(use);
    2947           } else if (use->is_MemBar()) {
    2948             memnode_worklist.append_if_missing(use);
    2949           }
    2950         }
    2951       }
    2952     } else if (n->is_AddP()) {
    2953       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
    2954       if (jobj == NULL || jobj == phantom_obj) {
    2955 #ifdef ASSERT
    2956         ptnode_adr(get_addp_base(n)->_idx)->dump();
    2957         ptnode_adr(n->_idx)->dump();
    2958         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
    2959 #endif
    2960         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
    2961         return;
    2962       }
    2963       Node *base = get_map(jobj->idx());  // CheckCastPP node
    2964       if (!split_AddP(n, base)) continue; // wrong type from dead path
    2965     } else if (n->is_Phi() ||
    2966                n->is_CheckCastPP() ||
    2967                n->is_EncodeP() ||
    2968                n->is_DecodeN() ||
    2969                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
    2970       if (visited.test_set(n->_idx)) {
    2971         assert(n->is_Phi(), "loops only through Phi's");
    2972         continue;  // already processed
    2973       }
    2974       JavaObjectNode* jobj = unique_java_object(n);
    2975       if (jobj == NULL || jobj == phantom_obj) {
    2976 #ifdef ASSERT
    2977         ptnode_adr(n->_idx)->dump();
    2978         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
    2979 #endif
    2980         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
    2981         return;
    2982       } else {
    2983         Node *val = get_map(jobj->idx());   // CheckCastPP node
    2984         TypeNode *tn = n->as_Type();
    2985         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
    2986         assert(tinst != NULL && tinst->is_known_instance() &&
    2987                tinst->instance_id() == jobj->idx() , "instance type expected.");
    2988
    2989         const Type *tn_type = igvn->type(tn);
    2990         const TypeOopPtr *tn_t;
    2991         if (tn_type->isa_narrowoop()) {
    2992           tn_t = tn_type->make_ptr()->isa_oopptr();
    2993         } else {
    2994           tn_t = tn_type->isa_oopptr();
    2995         }
    2996         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
    2997           if (tn_type->isa_narrowoop()) {
    2998             tn_type = tinst->make_narrowoop();
    2999           } else {
    3000             tn_type = tinst;
    3001           }
    3002           igvn->hash_delete(tn);
    3003           igvn->set_type(tn, tn_type);
    3004           tn->set_type(tn_type);
    3005           igvn->hash_insert(tn);
    3006           record_for_optimizer(n);
    3007         } else {
    3008           assert(tn_type == TypePtr::NULL_PTR ||
    3009                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
    3010                  "unexpected type");
    3011           continue; // Skip dead path with different type
    3012         }
    3013       }
    3014     } else {
    3015       debug_only(n->dump();)
    3016       assert(false, "EA: unexpected node");
    3017       continue;
    3018     }
    3019     // push allocation's users on appropriate worklist
    3020     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
    3021       Node *use = n->fast_out(i);
    3022       if(use->is_Mem() && use->in(MemNode::Address) == n) {
    3023         // Load/store to instance's field
    3024         memnode_worklist.append_if_missing(use);
    3025       } else if (use->is_MemBar()) {
    3026         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
    3027           memnode_worklist.append_if_missing(use);
    3028         }
    3029       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
    3030         Node* addp2 = find_second_addp(use, n);
    3031         if (addp2 != NULL) {
    3032           alloc_worklist.append_if_missing(addp2);
    3033         }
    3034         alloc_worklist.append_if_missing(use);
    3035       } else if (use->is_Phi() ||
    3036                  use->is_CheckCastPP() ||
    3037                  use->is_EncodeNarrowPtr() ||
    3038                  use->is_DecodeNarrowPtr() ||
    3039                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
    3040         alloc_worklist.append_if_missing(use);
    3041 #ifdef ASSERT
    3042       } else if (use->is_Mem()) {
    3043         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
    3044       } else if (use->is_MergeMem()) {
    3045         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
    3046       } else if (use->is_SafePoint()) {
    3047         // Look for MergeMem nodes for calls which reference unique allocation
    3048         // (through CheckCastPP nodes) even for debug info.
    3049         Node* m = use->in(TypeFunc::Memory);
    3050         if (m->is_MergeMem()) {
    3051           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
    3052         }
    3053       } else if (use->Opcode() == Op_EncodeISOArray) {
    3054         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
    3055           // EncodeISOArray overwrites destination array
    3056           memnode_worklist.append_if_missing(use);
    3057         }
    3058       } else {
    3059         uint op = use->Opcode();
    3060         if (!(op == Op_CmpP || op == Op_Conv2B ||
    3061               op == Op_CastP2X || op == Op_StoreCM ||
    3062               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
    3063               op == Op_StrEquals || op == Op_StrIndexOf)) {
    3064           n->dump();
    3065           use->dump();
    3066           assert(false, "EA: missing allocation reference path");
    3067         }
    3068 #endif
    3069       }
    3070     }
    3071
    3072   }
    3073   // New alias types were created in split_AddP().
    3074   uint new_index_end = (uint) _compile->num_alias_types();
    3075   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
    3076
    3077   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
    3078   //            compute new values for Memory inputs  (the Memory inputs are not
    3079   //            actually updated until phase 4.)
    3080   if (memnode_worklist.length() == 0)
    3081     return;  // nothing to do
    3082   while (memnode_worklist.length() != 0) {
    3083     Node *n = memnode_worklist.pop();
    3084     if (visited.test_set(n->_idx))
    3085       continue;
    3086     if (n->is_Phi() || n->is_ClearArray()) {
    3087       // we don't need to do anything, but the users must be pushed
    3088     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
    3089       // we don't need to do anything, but the users must be pushed
    3090       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
    3091       if (n == NULL)
    3092         continue;
    3093     } else if (n->Opcode() == Op_EncodeISOArray) {
    3094       // get the memory projection
    3095       n = n->find_out_with(Op_SCMemProj);
    3096       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
    3097     } else {
    3098       assert(n->is_Mem(), "memory node required.");
    3099       Node *addr = n->in(MemNode::Address);
    3100       const Type *addr_t = igvn->type(addr);
    3101       if (addr_t == Type::TOP)
    3102         continue;
    3103       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
    3104       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
    3105       assert ((uint)alias_idx < new_index_end, "wrong alias index");
    3106       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
    3107       if (_compile->failing()) {
    3108         return;
    3109       }
    3110       if (mem != n->in(MemNode::Memory)) {
    3111         // We delay the memory edge update since we need old one in
    3112         // MergeMem code below when instances memory slices are separated.
    3113         set_map(n, mem);
    3114       }
    3115       if (n->is_Load()) {
    3116         continue;  // don't push users
    3117       } else if (n->is_LoadStore()) {
    3118         // get the memory projection
    3119         n = n->find_out_with(Op_SCMemProj);
    3120         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
    3121       }
    3122     }
    3123     // push user on appropriate worklist
    3124     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
    3125       Node *use = n->fast_out(i);
    3126       if (use->is_Phi() || use->is_ClearArray()) {
    3127         memnode_worklist.append_if_missing(use);
    3128       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
    3129         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
    3130           continue;
    3131         memnode_worklist.append_if_missing(use);
    3132       } else if (use->is_MemBar()) {
    3133         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
    3134           memnode_worklist.append_if_missing(use);
    3135         }
    3136 #ifdef ASSERT
    3137       } else if(use->is_Mem()) {
    3138         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
    3139       } else if (use->is_MergeMem()) {
    3140         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
    3141       } else if (use->Opcode() == Op_EncodeISOArray) {
    3142         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
    3143           // EncodeISOArray overwrites destination array
    3144           memnode_worklist.append_if_missing(use);
    3145         }
    3146       } else {
    3147         uint op = use->Opcode();
    3148         if (!(op == Op_StoreCM ||
    3149               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
    3150                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
    3151               op == Op_AryEq || op == Op_StrComp ||
    3152               op == Op_StrEquals || op == Op_StrIndexOf)) {
    3153           n->dump();
    3154           use->dump();
    3155           assert(false, "EA: missing memory path");
    3156         }
    3157 #endif
    3158       }
    3159     }
    3160   }
    3161
    3162   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
    3163   //            Walk each memory slice moving the first node encountered of each
    3164   //            instance type to the the input corresponding to its alias index.
    3165   uint length = _mergemem_worklist.length();
    3166   for( uint next = 0; next < length; ++next ) {
    3167     MergeMemNode* nmm = _mergemem_worklist.at(next);
    3168     assert(!visited.test_set(nmm->_idx), "should not be visited before");
    3169     // Note: we don't want to use MergeMemStream here because we only want to
    3170     // scan inputs which exist at the start, not ones we add during processing.
    3171     // Note 2: MergeMem may already contains instance memory slices added
    3172     // during find_inst_mem() call when memory nodes were processed above.
    3173     igvn->hash_delete(nmm);
    3174     uint nslices = nmm->req();
    3175     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
    3176       Node* mem = nmm->in(i);
    3177       Node* cur = NULL;
    3178       if (mem == NULL || mem->is_top())
    3179         continue;
    3180       // First, update mergemem by moving memory nodes to corresponding slices
    3181       // if their type became more precise since this mergemem was created.
    3182       while (mem->is_Mem()) {
    3183         const Type *at = igvn->type(mem->in(MemNode::Address));
    3184         if (at != Type::TOP) {
    3185           assert (at->isa_ptr() != NULL, "pointer type required.");
    3186           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
    3187           if (idx == i) {
    3188             if (cur == NULL)
    3189               cur = mem;
    3190           } else {
    3191             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
    3192               nmm->set_memory_at(idx, mem);
    3193             }
    3194           }
    3195         }
    3196         mem = mem->in(MemNode::Memory);
    3197       }
    3198       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
    3199       // Find any instance of the current type if we haven't encountered
    3200       // already a memory slice of the instance along the memory chain.
    3201       for (uint ni = new_index_start; ni < new_index_end; ni++) {
    3202         if((uint)_compile->get_general_index(ni) == i) {
    3203           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
    3204           if (nmm->is_empty_memory(m)) {
    3205             Node* result = find_inst_mem(mem, ni, orig_phis);
    3206             if (_compile->failing()) {
    3207               return;
    3208             }
    3209             nmm->set_memory_at(ni, result);
    3210           }
    3211         }
    3212       }
    3213     }
    3214     // Find the rest of instances values
    3215     for (uint ni = new_index_start; ni < new_index_end; ni++) {
    3216       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
    3217       Node* result = step_through_mergemem(nmm, ni, tinst);
    3218       if (result == nmm->base_memory()) {
    3219         // Didn't find instance memory, search through general slice recursively.
    3220         result = nmm->memory_at(_compile->get_general_index(ni));
    3221         result = find_inst_mem(result, ni, orig_phis);
    3222         if (_compile->failing()) {
    3223           return;
    3224         }
    3225         nmm->set_memory_at(ni, result);
    3226       }
    3227     }
    3228     igvn->hash_insert(nmm);
    3229     record_for_optimizer(nmm);
    3230   }
    3231
    3232   //  Phase 4:  Update the inputs of non-instance memory Phis and
    3233   //            the Memory input of memnodes
    3234   // First update the inputs of any non-instance Phi's from
    3235   // which we split out an instance Phi.  Note we don't have
    3236   // to recursively process Phi's encounted on the input memory
    3237   // chains as is done in split_memory_phi() since they  will
    3238   // also be processed here.
    3239   for (int j = 0; j < orig_phis.length(); j++) {
    3240     PhiNode *phi = orig_phis.at(j);
    3241     int alias_idx = _compile->get_alias_index(phi->adr_type());
    3242     igvn->hash_delete(phi);
    3243     for (uint i = 1; i < phi->req(); i++) {
    3244       Node *mem = phi->in(i);
    3245       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
    3246       if (_compile->failing()) {
    3247         return;
    3248       }
    3249       if (mem != new_mem) {
    3250         phi->set_req(i, new_mem);
    3251       }
    3252     }
    3253     igvn->hash_insert(phi);
    3254     record_for_optimizer(phi);
    3255   }
    3256
    3257   // Update the memory inputs of MemNodes with the value we computed
    3258   // in Phase 2 and move stores memory users to corresponding memory slices.
    3259   // Disable memory split verification code until the fix for 6984348.
    3260   // Currently it produces false negative results since it does not cover all cases.
    3261 #if 0 // ifdef ASSERT
    3262   visited.Reset();
    3263   Node_Stack old_mems(arena, _compile->unique() >> 2);
    3264 #endif
    3265   for (uint i = 0; i < ideal_nodes.size(); i++) {
    3266     Node*    n = ideal_nodes.at(i);
    3267     Node* nmem = get_map(n->_idx);
    3268     assert(nmem != NULL, "sanity");
    3269     if (n->is_Mem()) {
    3270 #if 0 // ifdef ASSERT
    3271       Node* old_mem = n->in(MemNode::Memory);
    3272       if (!visited.test_set(old_mem->_idx)) {
    3273         old_mems.push(old_mem, old_mem->outcnt());
    3274       }
    3275 #endif
    3276       assert(n->in(MemNode::Memory) != nmem, "sanity");
    3277       if (!n->is_Load()) {
    3278         // Move memory users of a store first.
    3279         move_inst_mem(n, orig_phis);
    3280       }
    3281       // Now update memory input
    3282       igvn->hash_delete(n);
    3283       n->set_req(MemNode::Memory, nmem);
    3284       igvn->hash_insert(n);
    3285       record_for_optimizer(n);
    3286     } else {
    3287       assert(n->is_Allocate() || n->is_CheckCastPP() ||
    3288              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
    3289     }
    3290   }
    3291 #if 0 // ifdef ASSERT
    3292   // Verify that memory was split correctly
    3293   while (old_mems.is_nonempty()) {
    3294     Node* old_mem = old_mems.node();
    3295     uint  old_cnt = old_mems.index();
    3296     old_mems.pop();
    3297     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
    3298   }
    3299 #endif
    3300 }
    3301
    3302 #ifndef PRODUCT
    3303 static const char *node_type_names[] = {
    3304   "UnknownType",
    3305   "JavaObject",
    3306   "LocalVar",
    3307   "Field",
    3308   "Arraycopy"
    3309 };
    3310
    3311 static const char *esc_names[] = {
    3312   "UnknownEscape",
    3313   "NoEscape",
    3314   "ArgEscape",
    3315   "GlobalEscape"
    3316 };
    3317
    3318 void PointsToNode::dump(bool print_state) const {
    3319   NodeType nt = node_type();
    3320   tty->print("%s ", node_type_names[(int) nt]);
    3321   if (print_state) {
    3322     EscapeState es = escape_state();
    3323     EscapeState fields_es = fields_escape_state();
    3324     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
    3325     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
    3326       tty->print("NSR ");
    3327   }
    3328   if (is_Field()) {
    3329     FieldNode* f = (FieldNode*)this;
    3330     if (f->is_oop())
    3331       tty->print("oop ");
    3332     if (f->offset() > 0)
    3333       tty->print("+%d ", f->offset());
    3334     tty->print("(");
    3335     for (BaseIterator i(f); i.has_next(); i.next()) {
    3336       PointsToNode* b = i.get();
    3337       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
    3338     }
    3339     tty->print(" )");
    3340   }
    3341   tty->print("[");
    3342   for (EdgeIterator i(this); i.has_next(); i.next()) {
    3343     PointsToNode* e = i.get();
    3344     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
    3345   }
    3346   tty->print(" [");
    3347   for (UseIterator i(this); i.has_next(); i.next()) {
    3348     PointsToNode* u = i.get();
    3349     bool is_base = false;
    3350     if (PointsToNode::is_base_use(u)) {
    3351       is_base = true;
    3352       u = PointsToNode::get_use_node(u)->as_Field();
    3353     }
    3354     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
    3355   }
    3356   tty->print(" ]]  ");
    3357   if (_node == NULL)
    3358     tty->print_cr("<null>");
    3359   else
    3360     _node->dump();
    3361 }
    3362
    3363 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
    3364   bool first = true;
    3365   int ptnodes_length = ptnodes_worklist.length();
    3366   for (int i = 0; i < ptnodes_length; i++) {
    3367     PointsToNode *ptn = ptnodes_worklist.at(i);
    3368     if (ptn == NULL || !ptn->is_JavaObject())
    3369       continue;
    3370     PointsToNode::EscapeState es = ptn->escape_state();
    3371     if ((es != PointsToNode::NoEscape) && !Verbose) {
    3372       continue;
    3373     }
    3374     Node* n = ptn->ideal_node();
    3375     if (n->is_Allocate() || (n->is_CallStaticJava() &&
    3376                              n->as_CallStaticJava()->is_boxing_method())) {
    3377       if (first) {
    3378         tty->cr();
    3379         tty->print("======== Connection graph for ");
    3380         _compile->method()->print_short_name();
    3381         tty->cr();
    3382         first = false;
    3383       }
    3384       ptn->dump();
    3385       // Print all locals and fields which reference this allocation
    3386       for (UseIterator j(ptn); j.has_next(); j.next()) {
    3387         PointsToNode* use = j.get();
    3388         if (use->is_LocalVar()) {
    3389           use->dump(Verbose);
    3390         } else if (Verbose) {
    3391           use->dump();
    3392         }
    3393       }
    3394       tty->cr();
    3395     }
    3396   }
    3397 }
    3398 #endif