1 /*
   2  * Copyright (c) 2005, 2019, 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/rootnode.hpp"
  37 
  38 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  39   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  40   _in_worklist(C->comp_arena()),
  41   _next_pidx(0),
  42   _collecting(true),
  43   _verify(false),
  44   _compile(C),
  45   _igvn(igvn),
  46   _node_map(C->comp_arena()) {
  47   // Add unknown java object.
  48   add_java_object(C->top(), PointsToNode::GlobalEscape);
  49   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  50   // Add ConP(#NULL) and ConN(#NULL) nodes.
  51   Node* oop_null = igvn->zerocon(T_OBJECT);
  52   assert(oop_null->_idx < nodes_size(), "should be created already");
  53   add_java_object(oop_null, PointsToNode::NoEscape);
  54   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  55   if (UseCompressedOops) {
  56     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  57     assert(noop_null->_idx < nodes_size(), "should be created already");
  58     map_ideal_node(noop_null, null_obj);
  59   }
  60   _pcmp_neq = NULL; // Should be initialized
  61   _pcmp_eq  = NULL;
  62 }
  63 
  64 bool ConnectionGraph::has_candidates(Compile *C) {
  65   // EA brings benefits only when the code has allocations and/or locks which
  66   // are represented by ideal Macro nodes.
  67   int cnt = C->macro_count();
  68   for (int i = 0; i < cnt; i++) {
  69     Node *n = C->macro_node(i);
  70     if (n->is_Allocate())
  71       return true;
  72     if (n->is_Lock()) {
  73       Node* obj = n->as_Lock()->obj_node()->uncast();
  74       if (!(obj->is_Parm() || obj->is_Con()))
  75         return true;
  76     }
  77     if (n->is_CallStaticJava() &&
  78         n->as_CallStaticJava()->is_boxing_method()) {
  79       return true;
  80     }
  81   }
  82   return false;
  83 }
  84 
  85 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  86   Compile::TracePhase t2("escapeAnalysis", &Phase::_t_escapeAnalysis, true);
  87   ResourceMark rm;
  88 
  89   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  90   // to create space for them in ConnectionGraph::_nodes[].
  91   Node* oop_null = igvn->zerocon(T_OBJECT);
  92   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  93   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
  94   // Perform escape analysis
  95   if (congraph->compute_escape()) {
  96     // There are non escaping objects.
  97     C->set_congraph(congraph);
  98   }
  99   // Cleanup.
 100   if (oop_null->outcnt() == 0)
 101     igvn->hash_delete(oop_null);
 102   if (noop_null->outcnt() == 0)
 103     igvn->hash_delete(noop_null);
 104 }
 105 
 106 bool ConnectionGraph::compute_escape() {
 107   Compile* C = _compile;
 108   PhaseGVN* igvn = _igvn;
 109 
 110   // Worklists used by EA.
 111   Unique_Node_List delayed_worklist;
 112   GrowableArray<Node*> alloc_worklist;
 113   GrowableArray<Node*> ptr_cmp_worklist;
 114   GrowableArray<Node*> storestore_worklist;
 115   GrowableArray<PointsToNode*>   ptnodes_worklist;
 116   GrowableArray<JavaObjectNode*> java_objects_worklist;
 117   GrowableArray<JavaObjectNode*> non_escaped_worklist;
 118   GrowableArray<FieldNode*>      oop_fields_worklist;
 119   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 120 
 121   { Compile::TracePhase t3("connectionGraph", &Phase::_t_connectionGraph, true);
 122 
 123   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 124   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
 125   // Initialize worklist
 126   if (C->root() != NULL) {
 127     ideal_nodes.push(C->root());
 128   }
 129   // Processed ideal nodes are unique on ideal_nodes list
 130   // but several ideal nodes are mapped to the phantom_obj.
 131   // To avoid duplicated entries on the following worklists
 132   // add the phantom_obj only once to them.
 133   ptnodes_worklist.append(phantom_obj);
 134   java_objects_worklist.append(phantom_obj);
 135   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 136     Node* n = ideal_nodes.at(next);
 137     // Create PointsTo nodes and add them to Connection Graph. Called
 138     // only once per ideal node since ideal_nodes is Unique_Node list.
 139     add_node_to_connection_graph(n, &delayed_worklist);
 140     PointsToNode* ptn = ptnode_adr(n->_idx);
 141     if (ptn != NULL && ptn != phantom_obj) {
 142       ptnodes_worklist.append(ptn);
 143       if (ptn->is_JavaObject()) {
 144         java_objects_worklist.append(ptn->as_JavaObject());
 145         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 146             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 147           // Only allocations and java static calls results are interesting.
 148           non_escaped_worklist.append(ptn->as_JavaObject());
 149         }
 150       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 151         oop_fields_worklist.append(ptn->as_Field());
 152       }
 153     }
 154     if (n->is_MergeMem()) {
 155       // Collect all MergeMem nodes to add memory slices for
 156       // scalar replaceable objects in split_unique_types().
 157       _mergemem_worklist.append(n->as_MergeMem());
 158     } else if (OptimizePtrCompare && n->is_Cmp() &&
 159                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
 160       // Collect compare pointers nodes.
 161       ptr_cmp_worklist.append(n);
 162     } else if (n->is_MemBarStoreStore()) {
 163       // Collect all MemBarStoreStore nodes so that depending on the
 164       // escape status of the associated Allocate node some of them
 165       // may be eliminated.
 166       storestore_worklist.append(n);
 167     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
 168                (n->req() > MemBarNode::Precedent)) {
 169       record_for_optimizer(n);
 170 #ifdef ASSERT
 171     } else if (n->is_AddP()) {
 172       // Collect address nodes for graph verification.
 173       addp_worklist.append(n);
 174 #endif
 175     }
 176     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 177       Node* m = n->fast_out(i);   // Get user
 178       ideal_nodes.push(m);
 179     }
 180   }
 181   if (non_escaped_worklist.length() == 0) {
 182     _collecting = false;
 183     return false; // Nothing to do.
 184   }
 185   // Add final simple edges to graph.
 186   while(delayed_worklist.size() > 0) {
 187     Node* n = delayed_worklist.pop();
 188     add_final_edges(n);
 189   }
 190   int ptnodes_length = ptnodes_worklist.length();
 191 
 192 #ifdef ASSERT
 193   if (VerifyConnectionGraph) {
 194     // Verify that no new simple edges could be created and all
 195     // local vars has edges.
 196     _verify = true;
 197     for (int next = 0; next < ptnodes_length; ++next) {
 198       PointsToNode* ptn = ptnodes_worklist.at(next);
 199       add_final_edges(ptn->ideal_node());
 200       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 201         ptn->dump();
 202         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 203       }
 204     }
 205     _verify = false;
 206   }
 207 #endif
 208   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 209   // processing, calls to CI to resolve symbols (types, fields, methods)
 210   // referenced in bytecode. During symbol resolution VM may throw
 211   // an exception which CI cleans and converts to compilation failure.
 212   if (C->failing())  return false;
 213 
 214   // 2. Finish Graph construction by propagating references to all
 215   //    java objects through graph.
 216   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 217                                  java_objects_worklist, oop_fields_worklist)) {
 218     // All objects escaped or hit time or iterations limits.
 219     _collecting = false;
 220     return false;
 221   }
 222 
 223   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 224   //    scalar replaceable allocations on alloc_worklist for processing
 225   //    in split_unique_types().
 226   int non_escaped_length = non_escaped_worklist.length();
 227   for (int next = 0; next < non_escaped_length; next++) {
 228     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 229     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 230     Node* n = ptn->ideal_node();
 231     if (n->is_Allocate()) {
 232       n->as_Allocate()->_is_non_escaping = noescape;
 233     }
 234     if (n->is_CallStaticJava()) {
 235       n->as_CallStaticJava()->_is_non_escaping = noescape;
 236     }
 237     if (noescape && ptn->scalar_replaceable()) {
 238       adjust_scalar_replaceable_state(ptn);
 239       if (ptn->scalar_replaceable()) {
 240         alloc_worklist.append(ptn->ideal_node());
 241       }
 242     }
 243   }
 244 
 245 #ifdef ASSERT
 246   if (VerifyConnectionGraph) {
 247     // Verify that graph is complete - no new edges could be added or needed.
 248     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 249                             java_objects_worklist, addp_worklist);
 250   }
 251   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 252   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 253          null_obj->edge_count() == 0 &&
 254          !null_obj->arraycopy_src() &&
 255          !null_obj->arraycopy_dst(), "sanity");
 256 #endif
 257 
 258   _collecting = false;
 259 
 260   } // TracePhase t3("connectionGraph")
 261 
 262   // 4. Optimize ideal graph based on EA information.
 263   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 264   if (has_non_escaping_obj) {
 265     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 266   }
 267 
 268 #ifndef PRODUCT
 269   if (PrintEscapeAnalysis) {
 270     dump(ptnodes_worklist); // Dump ConnectionGraph
 271   }
 272 #endif
 273 
 274   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 275 #ifdef ASSERT
 276   if (VerifyConnectionGraph) {
 277     int alloc_length = alloc_worklist.length();
 278     for (int next = 0; next < alloc_length; ++next) {
 279       Node* n = alloc_worklist.at(next);
 280       PointsToNode* ptn = ptnode_adr(n->_idx);
 281       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 282     }
 283   }
 284 #endif
 285 
 286   // 5. Separate memory graph for scalar replaceable allcations.
 287   if (has_scalar_replaceable_candidates &&
 288       C->AliasLevel() >= 3 && EliminateAllocations) {
 289     // Now use the escape information to create unique types for
 290     // scalar replaceable objects.
 291     split_unique_types(alloc_worklist);
 292     if (C->failing())  return false;
 293     C->print_method(PHASE_AFTER_EA, 2);
 294 
 295 #ifdef ASSERT
 296   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 297     tty->print("=== No allocations eliminated for ");
 298     C->method()->print_short_name();
 299     if(!EliminateAllocations) {
 300       tty->print(" since EliminateAllocations is off ===");
 301     } else if(!has_scalar_replaceable_candidates) {
 302       tty->print(" since there are no scalar replaceable candidates ===");
 303     } else if(C->AliasLevel() < 3) {
 304       tty->print(" since AliasLevel < 3 ===");
 305     }
 306     tty->cr();
 307 #endif
 308   }
 309   return has_non_escaping_obj;
 310 }
 311 
 312 // Utility function for nodes that load an object
 313 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 314   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 315   // ThreadLocal has RawPtr type.
 316   const Type* t = _igvn->type(n);
 317   if (t->make_ptr() != NULL) {
 318     Node* adr = n->in(MemNode::Address);
 319 #ifdef ASSERT
 320     if (!adr->is_AddP()) {
 321       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 322     } else {
 323       assert((ptnode_adr(adr->_idx) == NULL ||
 324               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 325     }
 326 #endif
 327     add_local_var_and_edge(n, PointsToNode::NoEscape,
 328                            adr, delayed_worklist);
 329   }
 330 }
 331 
 332 // Populate Connection Graph with PointsTo nodes and create simple
 333 // connection graph edges.
 334 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 335   assert(!_verify, "this method sould not be called for verification");
 336   PhaseGVN* igvn = _igvn;
 337   uint n_idx = n->_idx;
 338   PointsToNode* n_ptn = ptnode_adr(n_idx);
 339   if (n_ptn != NULL)
 340     return; // No need to redefine PointsTo node during first iteration.
 341 
 342   if (n->is_Call()) {
 343     // Arguments to allocation and locking don't escape.
 344     if (n->is_AbstractLock()) {
 345       // Put Lock and Unlock nodes on IGVN worklist to process them during
 346       // first IGVN optimization when escape information is still available.
 347       record_for_optimizer(n);
 348     } else if (n->is_Allocate()) {
 349       add_call_node(n->as_Call());
 350       record_for_optimizer(n);
 351     } else {
 352       if (n->is_CallStaticJava()) {
 353         const char* name = n->as_CallStaticJava()->_name;
 354         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 355           return; // Skip uncommon traps
 356       }
 357       // Don't mark as processed since call's arguments have to be processed.
 358       delayed_worklist->push(n);
 359       // Check if a call returns an object.
 360       if ((n->as_Call()->returns_pointer() &&
 361            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
 362           (n->is_CallStaticJava() &&
 363            n->as_CallStaticJava()->is_boxing_method())) {
 364         add_call_node(n->as_Call());
 365       }
 366     }
 367     return;
 368   }
 369   // Put this check here to process call arguments since some call nodes
 370   // point to phantom_obj.
 371   if (n_ptn == phantom_obj || n_ptn == null_obj)
 372     return; // Skip predefined nodes.
 373 
 374   int opcode = n->Opcode();
 375   switch (opcode) {
 376     case Op_AddP: {
 377       Node* base = get_addp_base(n);
 378       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 379       // Field nodes are created for all field types. They are used in
 380       // adjust_scalar_replaceable_state() and split_unique_types().
 381       // Note, non-oop fields will have only base edges in Connection
 382       // Graph because such fields are not used for oop loads and stores.
 383       int offset = address_offset(n, igvn);
 384       add_field(n, PointsToNode::NoEscape, offset);
 385       if (ptn_base == NULL) {
 386         delayed_worklist->push(n); // Process it later.
 387       } else {
 388         n_ptn = ptnode_adr(n_idx);
 389         add_base(n_ptn->as_Field(), ptn_base);
 390       }
 391       break;
 392     }
 393     case Op_CastX2P: {
 394       map_ideal_node(n, phantom_obj);
 395       break;
 396     }
 397     case Op_CastPP:
 398     case Op_CheckCastPP:
 399     case Op_EncodeP:
 400     case Op_DecodeN:
 401     case Op_EncodePKlass:
 402     case Op_DecodeNKlass: {
 403       add_local_var_and_edge(n, PointsToNode::NoEscape,
 404                              n->in(1), delayed_worklist);
 405       break;
 406     }
 407     case Op_CMoveP: {
 408       add_local_var(n, PointsToNode::NoEscape);
 409       // Do not add edges during first iteration because some could be
 410       // not defined yet.
 411       delayed_worklist->push(n);
 412       break;
 413     }
 414     case Op_ConP:
 415     case Op_ConN:
 416     case Op_ConNKlass: {
 417       // assume all oop constants globally escape except for null
 418       PointsToNode::EscapeState es;
 419       const Type* t = igvn->type(n);
 420       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 421         es = PointsToNode::NoEscape;
 422       } else {
 423         es = PointsToNode::GlobalEscape;
 424       }
 425       add_java_object(n, es);
 426       break;
 427     }
 428     case Op_CreateEx: {
 429       // assume that all exception objects globally escape
 430       map_ideal_node(n, phantom_obj);
 431       break;
 432     }
 433     case Op_LoadKlass:
 434     case Op_LoadNKlass: {
 435       // Unknown class is loaded
 436       map_ideal_node(n, phantom_obj);
 437       break;
 438     }
 439     case Op_LoadP:
 440     case Op_LoadN:
 441     case Op_LoadPLocked: {
 442       add_objload_to_connection_graph(n, delayed_worklist);
 443       break;
 444     }
 445     case Op_Parm: {
 446       map_ideal_node(n, phantom_obj);
 447       break;
 448     }
 449     case Op_PartialSubtypeCheck: {
 450       // Produces Null or notNull and is used in only in CmpP so
 451       // phantom_obj could be used.
 452       map_ideal_node(n, phantom_obj); // Result is unknown
 453       break;
 454     }
 455     case Op_Phi: {
 456       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 457       // ThreadLocal has RawPtr type.
 458       const Type* t = n->as_Phi()->type();
 459       if (t->make_ptr() != NULL) {
 460         add_local_var(n, PointsToNode::NoEscape);
 461         // Do not add edges during first iteration because some could be
 462         // not defined yet.
 463         delayed_worklist->push(n);
 464       }
 465       break;
 466     }
 467     case Op_Proj: {
 468       // we are only interested in the oop result projection from a call
 469       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 470           n->in(0)->as_Call()->returns_pointer()) {
 471         add_local_var_and_edge(n, PointsToNode::NoEscape,
 472                                n->in(0), delayed_worklist);
 473       }
 474       break;
 475     }
 476     case Op_Rethrow: // Exception object escapes
 477     case Op_Return: {
 478       if (n->req() > TypeFunc::Parms &&
 479           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 480         // Treat Return value as LocalVar with GlobalEscape escape state.
 481         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 482                                n->in(TypeFunc::Parms), delayed_worklist);
 483       }
 484       break;
 485     }
 486     case Op_GetAndSetP:
 487     case Op_GetAndSetN: {
 488       add_objload_to_connection_graph(n, delayed_worklist);
 489       // fallthrough
 490     }
 491     case Op_StoreP:
 492     case Op_StoreN:
 493     case Op_StoreNKlass:
 494     case Op_StorePConditional:
 495     case Op_CompareAndSwapP:
 496     case Op_CompareAndSwapN: {
 497       Node* adr = n->in(MemNode::Address);
 498       const Type *adr_type = igvn->type(adr);
 499       adr_type = adr_type->make_ptr();
 500       if (adr_type == NULL) {
 501         break; // skip dead nodes
 502       }
 503       if (adr_type->isa_oopptr() ||
 504           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 505                         (adr_type == TypeRawPtr::NOTNULL &&
 506                          adr->in(AddPNode::Address)->is_Proj() &&
 507                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 508         delayed_worklist->push(n); // Process it later.
 509 #ifdef ASSERT
 510         assert(adr->is_AddP(), "expecting an AddP");
 511         if (adr_type == TypeRawPtr::NOTNULL) {
 512           // Verify a raw address for a store captured by Initialize node.
 513           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 514           assert(offs != Type::OffsetBot, "offset must be a constant");
 515         }
 516 #endif
 517       } else {
 518         // Ignore copy the displaced header to the BoxNode (OSR compilation).
 519         if (adr->is_BoxLock())
 520           break;
 521         // Stored value escapes in unsafe access.
 522         if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
 523           // Pointer stores in G1 barriers looks like unsafe access.
 524           // Ignore such stores to be able scalar replace non-escaping
 525           // allocations.
 526           if (UseG1GC && adr->is_AddP()) {
 527             Node* base = get_addp_base(adr);
 528             if (base->Opcode() == Op_LoadP &&
 529                 base->in(MemNode::Address)->is_AddP()) {
 530               adr = base->in(MemNode::Address);
 531               Node* tls = get_addp_base(adr);
 532               if (tls->Opcode() == Op_ThreadLocal) {
 533                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 534                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
 535                                      PtrQueue::byte_offset_of_buf())) {
 536                   break; // G1 pre barier previous oop value store.
 537                 }
 538                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
 539                                      PtrQueue::byte_offset_of_buf())) {
 540                   break; // G1 post barier card address store.
 541                 }
 542               }
 543             }
 544           }
 545           delayed_worklist->push(n); // Process unsafe access later.
 546           break;
 547         }
 548 #ifdef ASSERT
 549         n->dump(1);
 550         assert(false, "not unsafe or G1 barrier raw StoreP");
 551 #endif
 552       }
 553       break;
 554     }
 555     case Op_AryEq:
 556     case Op_StrComp:
 557     case Op_StrEquals:
 558     case Op_StrIndexOf:
 559     case Op_EncodeISOArray: {
 560       add_local_var(n, PointsToNode::ArgEscape);
 561       delayed_worklist->push(n); // Process it later.
 562       break;
 563     }
 564     case Op_ThreadLocal: {
 565       add_java_object(n, PointsToNode::ArgEscape);
 566       break;
 567     }
 568     default:
 569       ; // Do nothing for nodes not related to EA.
 570   }
 571   return;
 572 }
 573 
 574 #ifdef ASSERT
 575 #define ELSE_FAIL(name)                               \
 576       /* Should not be called for not pointer type. */  \
 577       n->dump(1);                                       \
 578       assert(false, name);                              \
 579       break;
 580 #else
 581 #define ELSE_FAIL(name) \
 582       break;
 583 #endif
 584 
 585 // Add final simple edges to graph.
 586 void ConnectionGraph::add_final_edges(Node *n) {
 587   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 588 #ifdef ASSERT
 589   if (_verify && n_ptn->is_JavaObject())
 590     return; // This method does not change graph for JavaObject.
 591 #endif
 592 
 593   if (n->is_Call()) {
 594     process_call_arguments(n->as_Call());
 595     return;
 596   }
 597   assert(n->is_Store() || n->is_LoadStore() ||
 598          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 599          "node should be registered already");
 600   int opcode = n->Opcode();
 601   switch (opcode) {
 602     case Op_AddP: {
 603       Node* base = get_addp_base(n);
 604       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 605       assert(ptn_base != NULL, "field's base should be registered");
 606       add_base(n_ptn->as_Field(), ptn_base);
 607       break;
 608     }
 609     case Op_CastPP:
 610     case Op_CheckCastPP:
 611     case Op_EncodeP:
 612     case Op_DecodeN:
 613     case Op_EncodePKlass:
 614     case Op_DecodeNKlass: {
 615       add_local_var_and_edge(n, PointsToNode::NoEscape,
 616                              n->in(1), NULL);
 617       break;
 618     }
 619     case Op_CMoveP: {
 620       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 621         Node* in = n->in(i);
 622         if (in == NULL)
 623           continue;  // ignore NULL
 624         Node* uncast_in = in->uncast();
 625         if (uncast_in->is_top() || uncast_in == n)
 626           continue;  // ignore top or inputs which go back this node
 627         PointsToNode* ptn = ptnode_adr(in->_idx);
 628         assert(ptn != NULL, "node should be registered");
 629         add_edge(n_ptn, ptn);
 630       }
 631       break;
 632     }
 633     case Op_LoadP:
 634     case Op_LoadN:
 635     case Op_LoadPLocked: {
 636       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 637       // ThreadLocal has RawPtr type.
 638       const Type* t = _igvn->type(n);
 639       if (t->make_ptr() != NULL) {
 640         Node* adr = n->in(MemNode::Address);
 641         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 642         break;
 643       }
 644       ELSE_FAIL("Op_LoadP");
 645     }
 646     case Op_Phi: {
 647       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 648       // ThreadLocal has RawPtr type.
 649       const Type* t = n->as_Phi()->type();
 650       if (t->make_ptr() != NULL) {
 651         for (uint i = 1; i < n->req(); i++) {
 652           Node* in = n->in(i);
 653           if (in == NULL)
 654             continue;  // ignore NULL
 655           Node* uncast_in = in->uncast();
 656           if (uncast_in->is_top() || uncast_in == n)
 657             continue;  // ignore top or inputs which go back this node
 658           PointsToNode* ptn = ptnode_adr(in->_idx);
 659           assert(ptn != NULL, "node should be registered");
 660           add_edge(n_ptn, ptn);
 661         }
 662         break;
 663       }
 664       ELSE_FAIL("Op_Phi");
 665     }
 666     case Op_Proj: {
 667       // we are only interested in the oop result projection from a call
 668       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 669           n->in(0)->as_Call()->returns_pointer()) {
 670         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 671         break;
 672       }
 673       ELSE_FAIL("Op_Proj");
 674     }
 675     case Op_Rethrow: // Exception object escapes
 676     case Op_Return: {
 677       if (n->req() > TypeFunc::Parms &&
 678           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 679         // Treat Return value as LocalVar with GlobalEscape escape state.
 680         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 681                                n->in(TypeFunc::Parms), NULL);
 682         break;
 683       }
 684       ELSE_FAIL("Op_Return");
 685     }
 686     case Op_StoreP:
 687     case Op_StoreN:
 688     case Op_StoreNKlass:
 689     case Op_StorePConditional:
 690     case Op_CompareAndSwapP:
 691     case Op_CompareAndSwapN:
 692     case Op_GetAndSetP:
 693     case Op_GetAndSetN: {
 694       Node* adr = n->in(MemNode::Address);
 695       const Type *adr_type = _igvn->type(adr);
 696       adr_type = adr_type->make_ptr();
 697 #ifdef ASSERT
 698       if (adr_type == NULL) {
 699         n->dump(1);
 700         assert(adr_type != NULL, "dead node should not be on list");
 701         break;
 702       }
 703 #endif
 704       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
 705         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 706       }
 707       if (adr_type->isa_oopptr() ||
 708           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 709                         (adr_type == TypeRawPtr::NOTNULL &&
 710                          adr->in(AddPNode::Address)->is_Proj() &&
 711                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 712         // Point Address to Value
 713         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 714         assert(adr_ptn != NULL &&
 715                adr_ptn->as_Field()->is_oop(), "node should be registered");
 716         Node *val = n->in(MemNode::ValueIn);
 717         PointsToNode* ptn = ptnode_adr(val->_idx);
 718         assert(ptn != NULL, "node should be registered");
 719         add_edge(adr_ptn, ptn);
 720         break;
 721       } else if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
 722         // Stored value escapes in unsafe access.
 723         Node *val = n->in(MemNode::ValueIn);
 724         PointsToNode* ptn = ptnode_adr(val->_idx);
 725         assert(ptn != NULL, "node should be registered");
 726         set_escape_state(ptn, PointsToNode::GlobalEscape);
 727         // Add edge to object for unsafe access with offset.
 728         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 729         assert(adr_ptn != NULL, "node should be registered");
 730         if (adr_ptn->is_Field()) {
 731           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 732           add_edge(adr_ptn, ptn);
 733         }
 734         break;
 735       }
 736       ELSE_FAIL("Op_StoreP");
 737     }
 738     case Op_AryEq:
 739     case Op_StrComp:
 740     case Op_StrEquals:
 741     case Op_StrIndexOf:
 742     case Op_EncodeISOArray: {
 743       // char[] arrays passed to string intrinsic do not escape but
 744       // they are not scalar replaceable. Adjust escape state for them.
 745       // Start from in(2) edge since in(1) is memory edge.
 746       for (uint i = 2; i < n->req(); i++) {
 747         Node* adr = n->in(i);
 748         const Type* at = _igvn->type(adr);
 749         if (!adr->is_top() && at->isa_ptr()) {
 750           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 751                  at->isa_ptr() != NULL, "expecting a pointer");
 752           if (adr->is_AddP()) {
 753             adr = get_addp_base(adr);
 754           }
 755           PointsToNode* ptn = ptnode_adr(adr->_idx);
 756           assert(ptn != NULL, "node should be registered");
 757           add_edge(n_ptn, ptn);
 758         }
 759       }
 760       break;
 761     }
 762     default: {
 763       // This method should be called only for EA specific nodes which may
 764       // miss some edges when they were created.
 765 #ifdef ASSERT
 766       n->dump(1);
 767 #endif
 768       guarantee(false, "unknown node");
 769     }
 770   }
 771   return;
 772 }
 773 
 774 void ConnectionGraph::add_call_node(CallNode* call) {
 775   assert(call->returns_pointer(), "only for call which returns pointer");
 776   uint call_idx = call->_idx;
 777   if (call->is_Allocate()) {
 778     Node* k = call->in(AllocateNode::KlassNode);
 779     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 780     assert(kt != NULL, "TypeKlassPtr  required.");
 781     ciKlass* cik = kt->klass();
 782     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 783     bool scalar_replaceable = true;
 784     if (call->is_AllocateArray()) {
 785       if (!cik->is_array_klass()) { // StressReflectiveCode
 786         es = PointsToNode::GlobalEscape;
 787       } else {
 788         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 789         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 790           // Not scalar replaceable if the length is not constant or too big.
 791           scalar_replaceable = false;
 792         }
 793       }
 794     } else {  // Allocate instance
 795       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 796           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 797          !cik->is_instance_klass() || // StressReflectiveCode
 798           cik->as_instance_klass()->has_finalizer()) {
 799         es = PointsToNode::GlobalEscape;
 800       }
 801     }
 802     add_java_object(call, es);
 803     PointsToNode* ptn = ptnode_adr(call_idx);
 804     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 805       ptn->set_scalar_replaceable(false);
 806     }
 807   } else if (call->is_CallStaticJava()) {
 808     // Call nodes could be different types:
 809     //
 810     // 1. CallDynamicJavaNode (what happened during call is unknown):
 811     //
 812     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 813     //
 814     //    - all oop arguments are escaping globally;
 815     //
 816     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 817     //
 818     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 819     //
 820     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 821     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 822     //      during call is returned;
 823     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 824     //      which are returned and does not escape during call;
 825     //
 826     //    - oop arguments escaping status is defined by bytecode analysis;
 827     //
 828     // For a static call, we know exactly what method is being called.
 829     // Use bytecode estimator to record whether the call's return value escapes.
 830     ciMethod* meth = call->as_CallJava()->method();
 831     if (meth == NULL) {
 832       const char* name = call->as_CallStaticJava()->_name;
 833       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 834       // Returns a newly allocated unescaped object.
 835       add_java_object(call, PointsToNode::NoEscape);
 836       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 837     } else if (meth->is_boxing_method()) {
 838       // Returns boxing object
 839       PointsToNode::EscapeState es;
 840       vmIntrinsics::ID intr = meth->intrinsic_id();
 841       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 842         // It does not escape if object is always allocated.
 843         es = PointsToNode::NoEscape;
 844       } else {
 845         // It escapes globally if object could be loaded from cache.
 846         es = PointsToNode::GlobalEscape;
 847       }
 848       add_java_object(call, es);
 849     } else {
 850       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 851       call_analyzer->copy_dependencies(_compile->dependencies());
 852       if (call_analyzer->is_return_allocated()) {
 853         // Returns a newly allocated unescaped object, simply
 854         // update dependency information.
 855         // Mark it as NoEscape so that objects referenced by
 856         // it's fields will be marked as NoEscape at least.
 857         add_java_object(call, PointsToNode::NoEscape);
 858         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 859       } else {
 860         // Determine whether any arguments are returned.
 861         const TypeTuple* d = call->tf()->domain();
 862         bool ret_arg = false;
 863         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 864           if (d->field_at(i)->isa_ptr() != NULL &&
 865               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 866             ret_arg = true;
 867             break;
 868           }
 869         }
 870         if (ret_arg) {
 871           add_local_var(call, PointsToNode::ArgEscape);
 872         } else {
 873           // Returns unknown object.
 874           map_ideal_node(call, phantom_obj);
 875         }
 876       }
 877     }
 878   } else {
 879     // An other type of call, assume the worst case:
 880     // returned value is unknown and globally escapes.
 881     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 882     map_ideal_node(call, phantom_obj);
 883   }
 884 }
 885 
 886 void ConnectionGraph::process_call_arguments(CallNode *call) {
 887     bool is_arraycopy = false;
 888     switch (call->Opcode()) {
 889 #ifdef ASSERT
 890     case Op_Allocate:
 891     case Op_AllocateArray:
 892     case Op_Lock:
 893     case Op_Unlock:
 894       assert(false, "should be done already");
 895       break;
 896 #endif
 897     case Op_CallLeafNoFP:
 898       is_arraycopy = (call->as_CallLeaf()->_name != NULL &&
 899                       strstr(call->as_CallLeaf()->_name, "arraycopy") != 0);
 900       // fall through
 901     case Op_CallLeaf: {
 902       // Stub calls, objects do not escape but they are not scale replaceable.
 903       // Adjust escape state for outgoing arguments.
 904       const TypeTuple * d = call->tf()->domain();
 905       bool src_has_oops = false;
 906       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 907         const Type* at = d->field_at(i);
 908         Node *arg = call->in(i);
 909         const Type *aat = _igvn->type(arg);
 910         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 911           continue;
 912         if (arg->is_AddP()) {
 913           //
 914           // The inline_native_clone() case when the arraycopy stub is called
 915           // after the allocation before Initialize and CheckCastPP nodes.
 916           // Or normal arraycopy for object arrays case.
 917           //
 918           // Set AddP's base (Allocate) as not scalar replaceable since
 919           // pointer to the base (with offset) is passed as argument.
 920           //
 921           arg = get_addp_base(arg);
 922         }
 923         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 924         assert(arg_ptn != NULL, "should be registered");
 925         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 926         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 927           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 928                  aat->isa_ptr() != NULL, "expecting an Ptr");
 929           bool arg_has_oops = aat->isa_oopptr() &&
 930                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 931                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 932           if (i == TypeFunc::Parms) {
 933             src_has_oops = arg_has_oops;
 934           }
 935           //
 936           // src or dst could be j.l.Object when other is basic type array:
 937           //
 938           //   arraycopy(char[],0,Object*,0,size);
 939           //   arraycopy(Object*,0,char[],0,size);
 940           //
 941           // Don't add edges in such cases.
 942           //
 943           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 944                                        arg_has_oops && (i > TypeFunc::Parms);
 945 #ifdef ASSERT
 946           if (!(is_arraycopy ||
 947                 (call->as_CallLeaf()->_name != NULL &&
 948                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
 949                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
 950                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 951                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 952                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 953                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 954                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 955                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 956                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 957                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 958                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 959                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 960                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 961                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 962                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 963                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
 964                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
 965                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
 966                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0)
 967                  ))) {
 968             call->dump();
 969             fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
 970           }
 971 #endif
 972           // Always process arraycopy's destination object since
 973           // we need to add all possible edges to references in
 974           // source object.
 975           if (arg_esc >= PointsToNode::ArgEscape &&
 976               !arg_is_arraycopy_dest) {
 977             continue;
 978           }
 979           set_escape_state(arg_ptn, PointsToNode::ArgEscape);
 980           if (arg_is_arraycopy_dest) {
 981             Node* src = call->in(TypeFunc::Parms);
 982             if (src->is_AddP()) {
 983               src = get_addp_base(src);
 984             }
 985             PointsToNode* src_ptn = ptnode_adr(src->_idx);
 986             assert(src_ptn != NULL, "should be registered");
 987             if (arg_ptn != src_ptn) {
 988               // Special arraycopy edge:
 989               // A destination object's field can't have the source object
 990               // as base since objects escape states are not related.
 991               // Only escape state of destination object's fields affects
 992               // escape state of fields in source object.
 993               add_arraycopy(call, PointsToNode::ArgEscape, src_ptn, arg_ptn);
 994             }
 995           }
 996         }
 997       }
 998       break;
 999     }
1000     case Op_CallStaticJava: {
1001       // For a static call, we know exactly what method is being called.
1002       // Use bytecode estimator to record the call's escape affects
1003 #ifdef ASSERT
1004       const char* name = call->as_CallStaticJava()->_name;
1005       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1006 #endif
1007       ciMethod* meth = call->as_CallJava()->method();
1008       if ((meth != NULL) && meth->is_boxing_method()) {
1009         break; // Boxing methods do not modify any oops.
1010       }
1011       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1012       // fall-through if not a Java method or no analyzer information
1013       if (call_analyzer != NULL) {
1014         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1015         const TypeTuple* d = call->tf()->domain();
1016         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1017           const Type* at = d->field_at(i);
1018           int k = i - TypeFunc::Parms;
1019           Node* arg = call->in(i);
1020           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1021           if (at->isa_ptr() != NULL &&
1022               call_analyzer->is_arg_returned(k)) {
1023             // The call returns arguments.
1024             if (call_ptn != NULL) { // Is call's result used?
1025               assert(call_ptn->is_LocalVar(), "node should be registered");
1026               assert(arg_ptn != NULL, "node should be registered");
1027               add_edge(call_ptn, arg_ptn);
1028             }
1029           }
1030           if (at->isa_oopptr() != NULL &&
1031               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1032             if (!call_analyzer->is_arg_stack(k)) {
1033               // The argument global escapes
1034               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1035             } else {
1036               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1037               if (!call_analyzer->is_arg_local(k)) {
1038                 // The argument itself doesn't escape, but any fields might
1039                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1040               }
1041             }
1042           }
1043         }
1044         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1045           // The call returns arguments.
1046           assert(call_ptn->edge_count() > 0, "sanity");
1047           if (!call_analyzer->is_return_local()) {
1048             // Returns also unknown object.
1049             add_edge(call_ptn, phantom_obj);
1050           }
1051         }
1052         break;
1053       }
1054     }
1055     default: {
1056       // Fall-through here if not a Java method or no analyzer information
1057       // or some other type of call, assume the worst case: all arguments
1058       // globally escape.
1059       const TypeTuple* d = call->tf()->domain();
1060       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1061         const Type* at = d->field_at(i);
1062         if (at->isa_oopptr() != NULL) {
1063           Node* arg = call->in(i);
1064           if (arg->is_AddP()) {
1065             arg = get_addp_base(arg);
1066           }
1067           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1068           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1069         }
1070       }
1071     }
1072   }
1073 }
1074 
1075 
1076 // Finish Graph construction.
1077 bool ConnectionGraph::complete_connection_graph(
1078                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1079                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1080                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1081                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1082   // Normally only 1-3 passes needed to build Connection Graph depending
1083   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1084   // Set limit to 20 to catch situation when something did go wrong and
1085   // bailout Escape Analysis.
1086   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1087 #define CG_BUILD_ITER_LIMIT 20
1088 
1089   // Propagate GlobalEscape and ArgEscape escape states and check that
1090   // we still have non-escaping objects. The method pushs on _worklist
1091   // Field nodes which reference phantom_object.
1092   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1093     return false; // Nothing to do.
1094   }
1095   // Now propagate references to all JavaObject nodes.
1096   int java_objects_length = java_objects_worklist.length();
1097   elapsedTimer time;
1098   bool timeout = false;
1099   int new_edges = 1;
1100   int iterations = 0;
1101   do {
1102     while ((new_edges > 0) &&
1103            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1104       double start_time = time.seconds();
1105       time.start();
1106       new_edges = 0;
1107       // Propagate references to phantom_object for nodes pushed on _worklist
1108       // by find_non_escaped_objects() and find_field_value().
1109       new_edges += add_java_object_edges(phantom_obj, false);
1110       for (int next = 0; next < java_objects_length; ++next) {
1111         JavaObjectNode* ptn = java_objects_worklist.at(next);
1112         new_edges += add_java_object_edges(ptn, true);
1113 
1114 #define SAMPLE_SIZE 4
1115         if ((next % SAMPLE_SIZE) == 0) {
1116           // Each 4 iterations calculate how much time it will take
1117           // to complete graph construction.
1118           time.stop();
1119           // Poll for requests from shutdown mechanism to quiesce compiler
1120           // because Connection graph construction may take long time.
1121           CompileBroker::maybe_block();
1122           double stop_time = time.seconds();
1123           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1124           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1125           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1126             timeout = true;
1127             break; // Timeout
1128           }
1129           start_time = stop_time;
1130           time.start();
1131         }
1132 #undef SAMPLE_SIZE
1133 
1134       }
1135       if (timeout) break;
1136       if (new_edges > 0) {
1137         // Update escape states on each iteration if graph was updated.
1138         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1139           return false; // Nothing to do.
1140         }
1141       }
1142       time.stop();
1143       if (time.seconds() >= EscapeAnalysisTimeout) {
1144         timeout = true;
1145         break;
1146       }
1147     }
1148     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1149       time.start();
1150       // Find fields which have unknown value.
1151       int fields_length = oop_fields_worklist.length();
1152       for (int next = 0; next < fields_length; next++) {
1153         FieldNode* field = oop_fields_worklist.at(next);
1154         if (field->edge_count() == 0) {
1155           new_edges += find_field_value(field);
1156           // This code may added new edges to phantom_object.
1157           // Need an other cycle to propagate references to phantom_object.
1158         }
1159       }
1160       time.stop();
1161       if (time.seconds() >= EscapeAnalysisTimeout) {
1162         timeout = true;
1163         break;
1164       }
1165     } else {
1166       new_edges = 0; // Bailout
1167     }
1168   } while (new_edges > 0);
1169 
1170   // Bailout if passed limits.
1171   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1172     Compile* C = _compile;
1173     if (C->log() != NULL) {
1174       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1175       C->log()->text("%s", timeout ? "time" : "iterations");
1176       C->log()->end_elem(" limit'");
1177     }
1178     assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1179            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
1180     // Possible infinite build_connection_graph loop,
1181     // bailout (no changes to ideal graph were made).
1182     return false;
1183   }
1184 #ifdef ASSERT
1185   if (Verbose && PrintEscapeAnalysis) {
1186     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1187                   iterations, nodes_size(), ptnodes_worklist.length());
1188   }
1189 #endif
1190 
1191 #undef CG_BUILD_ITER_LIMIT
1192 
1193   // Find fields initialized by NULL for non-escaping Allocations.
1194   int non_escaped_length = non_escaped_worklist.length();
1195   for (int next = 0; next < non_escaped_length; next++) {
1196     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1197     PointsToNode::EscapeState es = ptn->escape_state();
1198     assert(es <= PointsToNode::ArgEscape, "sanity");
1199     if (es == PointsToNode::NoEscape) {
1200       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1201         // Adding references to NULL object does not change escape states
1202         // since it does not escape. Also no fields are added to NULL object.
1203         add_java_object_edges(null_obj, false);
1204       }
1205     }
1206     Node* n = ptn->ideal_node();
1207     if (n->is_Allocate()) {
1208       // The object allocated by this Allocate node will never be
1209       // seen by an other thread. Mark it so that when it is
1210       // expanded no MemBarStoreStore is added.
1211       InitializeNode* ini = n->as_Allocate()->initialization();
1212       if (ini != NULL)
1213         ini->set_does_not_escape();
1214     }
1215   }
1216   return true; // Finished graph construction.
1217 }
1218 
1219 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1220 // and check that we still have non-escaping java objects.
1221 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1222                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1223   GrowableArray<PointsToNode*> escape_worklist;
1224   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1225   int ptnodes_length = ptnodes_worklist.length();
1226   for (int next = 0; next < ptnodes_length; ++next) {
1227     PointsToNode* ptn = ptnodes_worklist.at(next);
1228     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1229         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1230       escape_worklist.push(ptn);
1231     }
1232   }
1233   // Set escape states to referenced nodes (edges list).
1234   while (escape_worklist.length() > 0) {
1235     PointsToNode* ptn = escape_worklist.pop();
1236     PointsToNode::EscapeState es  = ptn->escape_state();
1237     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1238     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1239         es >= PointsToNode::ArgEscape) {
1240       // GlobalEscape or ArgEscape state of field means it has unknown value.
1241       if (add_edge(ptn, phantom_obj)) {
1242         // New edge was added
1243         add_field_uses_to_worklist(ptn->as_Field());
1244       }
1245     }
1246     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1247       PointsToNode* e = i.get();
1248       if (e->is_Arraycopy()) {
1249         assert(ptn->arraycopy_dst(), "sanity");
1250         // Propagate only fields escape state through arraycopy edge.
1251         if (e->fields_escape_state() < field_es) {
1252           set_fields_escape_state(e, field_es);
1253           escape_worklist.push(e);
1254         }
1255       } else if (es >= field_es) {
1256         // fields_escape_state is also set to 'es' if it is less than 'es'.
1257         if (e->escape_state() < es) {
1258           set_escape_state(e, es);
1259           escape_worklist.push(e);
1260         }
1261       } else {
1262         // Propagate field escape state.
1263         bool es_changed = false;
1264         if (e->fields_escape_state() < field_es) {
1265           set_fields_escape_state(e, field_es);
1266           es_changed = true;
1267         }
1268         if ((e->escape_state() < field_es) &&
1269             e->is_Field() && ptn->is_JavaObject() &&
1270             e->as_Field()->is_oop()) {
1271           // Change escape state of referenced fileds.
1272           set_escape_state(e, field_es);
1273           es_changed = true;;
1274         } else if (e->escape_state() < es) {
1275           set_escape_state(e, es);
1276           es_changed = true;;
1277         }
1278         if (es_changed) {
1279           escape_worklist.push(e);
1280         }
1281       }
1282     }
1283   }
1284   // Remove escaped objects from non_escaped list.
1285   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1286     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1287     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1288       non_escaped_worklist.delete_at(next);
1289     }
1290     if (ptn->escape_state() == PointsToNode::NoEscape) {
1291       // Find fields in non-escaped allocations which have unknown value.
1292       find_init_values(ptn, phantom_obj, NULL);
1293     }
1294   }
1295   return (non_escaped_worklist.length() > 0);
1296 }
1297 
1298 // Add all references to JavaObject node by walking over all uses.
1299 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1300   int new_edges = 0;
1301   if (populate_worklist) {
1302     // Populate _worklist by uses of jobj's uses.
1303     for (UseIterator i(jobj); i.has_next(); i.next()) {
1304       PointsToNode* use = i.get();
1305       if (use->is_Arraycopy())
1306         continue;
1307       add_uses_to_worklist(use);
1308       if (use->is_Field() && use->as_Field()->is_oop()) {
1309         // Put on worklist all field's uses (loads) and
1310         // related field nodes (same base and offset).
1311         add_field_uses_to_worklist(use->as_Field());
1312       }
1313     }
1314   }
1315   for (int l = 0; l < _worklist.length(); l++) {
1316     PointsToNode* use = _worklist.at(l);
1317     if (PointsToNode::is_base_use(use)) {
1318       // Add reference from jobj to field and from field to jobj (field's base).
1319       use = PointsToNode::get_use_node(use)->as_Field();
1320       if (add_base(use->as_Field(), jobj)) {
1321         new_edges++;
1322       }
1323       continue;
1324     }
1325     assert(!use->is_JavaObject(), "sanity");
1326     if (use->is_Arraycopy()) {
1327       if (jobj == null_obj) // NULL object does not have field edges
1328         continue;
1329       // Added edge from Arraycopy node to arraycopy's source java object
1330       if (add_edge(use, jobj)) {
1331         jobj->set_arraycopy_src();
1332         new_edges++;
1333       }
1334       // and stop here.
1335       continue;
1336     }
1337     if (!add_edge(use, jobj))
1338       continue; // No new edge added, there was such edge already.
1339     new_edges++;
1340     if (use->is_LocalVar()) {
1341       add_uses_to_worklist(use);
1342       if (use->arraycopy_dst()) {
1343         for (EdgeIterator i(use); i.has_next(); i.next()) {
1344           PointsToNode* e = i.get();
1345           if (e->is_Arraycopy()) {
1346             if (jobj == null_obj) // NULL object does not have field edges
1347               continue;
1348             // Add edge from arraycopy's destination java object to Arraycopy node.
1349             if (add_edge(jobj, e)) {
1350               new_edges++;
1351               jobj->set_arraycopy_dst();
1352             }
1353           }
1354         }
1355       }
1356     } else {
1357       // Added new edge to stored in field values.
1358       // Put on worklist all field's uses (loads) and
1359       // related field nodes (same base and offset).
1360       add_field_uses_to_worklist(use->as_Field());
1361     }
1362   }
1363   _worklist.clear();
1364   _in_worklist.Reset();
1365   return new_edges;
1366 }
1367 
1368 // Put on worklist all related field nodes.
1369 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1370   assert(field->is_oop(), "sanity");
1371   int offset = field->offset();
1372   add_uses_to_worklist(field);
1373   // Loop over all bases of this field and push on worklist Field nodes
1374   // with the same offset and base (since they may reference the same field).
1375   for (BaseIterator i(field); i.has_next(); i.next()) {
1376     PointsToNode* base = i.get();
1377     add_fields_to_worklist(field, base);
1378     // Check if the base was source object of arraycopy and go over arraycopy's
1379     // destination objects since values stored to a field of source object are
1380     // accessable by uses (loads) of fields of destination objects.
1381     if (base->arraycopy_src()) {
1382       for (UseIterator j(base); j.has_next(); j.next()) {
1383         PointsToNode* arycp = j.get();
1384         if (arycp->is_Arraycopy()) {
1385           for (UseIterator k(arycp); k.has_next(); k.next()) {
1386             PointsToNode* abase = k.get();
1387             if (abase->arraycopy_dst() && abase != base) {
1388               // Look for the same arracopy reference.
1389               add_fields_to_worklist(field, abase);
1390             }
1391           }
1392         }
1393       }
1394     }
1395   }
1396 }
1397 
1398 // Put on worklist all related field nodes.
1399 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1400   int offset = field->offset();
1401   if (base->is_LocalVar()) {
1402     for (UseIterator j(base); j.has_next(); j.next()) {
1403       PointsToNode* f = j.get();
1404       if (PointsToNode::is_base_use(f)) { // Field
1405         f = PointsToNode::get_use_node(f);
1406         if (f == field || !f->as_Field()->is_oop())
1407           continue;
1408         int offs = f->as_Field()->offset();
1409         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1410           add_to_worklist(f);
1411         }
1412       }
1413     }
1414   } else {
1415     assert(base->is_JavaObject(), "sanity");
1416     if (// Skip phantom_object since it is only used to indicate that
1417         // this field's content globally escapes.
1418         (base != phantom_obj) &&
1419         // NULL object node does not have fields.
1420         (base != null_obj)) {
1421       for (EdgeIterator i(base); i.has_next(); i.next()) {
1422         PointsToNode* f = i.get();
1423         // Skip arraycopy edge since store to destination object field
1424         // does not update value in source object field.
1425         if (f->is_Arraycopy()) {
1426           assert(base->arraycopy_dst(), "sanity");
1427           continue;
1428         }
1429         if (f == field || !f->as_Field()->is_oop())
1430           continue;
1431         int offs = f->as_Field()->offset();
1432         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1433           add_to_worklist(f);
1434         }
1435       }
1436     }
1437   }
1438 }
1439 
1440 // Find fields which have unknown value.
1441 int ConnectionGraph::find_field_value(FieldNode* field) {
1442   // Escaped fields should have init value already.
1443   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1444   int new_edges = 0;
1445   for (BaseIterator i(field); i.has_next(); i.next()) {
1446     PointsToNode* base = i.get();
1447     if (base->is_JavaObject()) {
1448       // Skip Allocate's fields which will be processed later.
1449       if (base->ideal_node()->is_Allocate())
1450         return 0;
1451       assert(base == null_obj, "only NULL ptr base expected here");
1452     }
1453   }
1454   if (add_edge(field, phantom_obj)) {
1455     // New edge was added
1456     new_edges++;
1457     add_field_uses_to_worklist(field);
1458   }
1459   return new_edges;
1460 }
1461 
1462 // Find fields initializing values for allocations.
1463 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1464   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1465   int new_edges = 0;
1466   Node* alloc = pta->ideal_node();
1467   if (init_val == phantom_obj) {
1468     // Do nothing for Allocate nodes since its fields values are "known".
1469     if (alloc->is_Allocate())
1470       return 0;
1471     assert(alloc->as_CallStaticJava(), "sanity");
1472 #ifdef ASSERT
1473     if (alloc->as_CallStaticJava()->method() == NULL) {
1474       const char* name = alloc->as_CallStaticJava()->_name;
1475       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1476     }
1477 #endif
1478     // Non-escaped allocation returned from Java or runtime call have
1479     // unknown values in fields.
1480     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1481       PointsToNode* field = i.get();
1482       if (field->is_Field() && field->as_Field()->is_oop()) {
1483         if (add_edge(field, phantom_obj)) {
1484           // New edge was added
1485           new_edges++;
1486           add_field_uses_to_worklist(field->as_Field());
1487         }
1488       }
1489     }
1490     return new_edges;
1491   }
1492   assert(init_val == null_obj, "sanity");
1493   // Do nothing for Call nodes since its fields values are unknown.
1494   if (!alloc->is_Allocate())
1495     return 0;
1496 
1497   InitializeNode* ini = alloc->as_Allocate()->initialization();
1498   Compile* C = _compile;
1499   bool visited_bottom_offset = false;
1500   GrowableArray<int> offsets_worklist;
1501 
1502   // Check if an oop field's initializing value is recorded and add
1503   // a corresponding NULL if field's value if it is not recorded.
1504   // Connection Graph does not record a default initialization by NULL
1505   // captured by Initialize node.
1506   //
1507   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1508     PointsToNode* field = i.get(); // Field (AddP)
1509     if (!field->is_Field() || !field->as_Field()->is_oop())
1510       continue; // Not oop field
1511     int offset = field->as_Field()->offset();
1512     if (offset == Type::OffsetBot) {
1513       if (!visited_bottom_offset) {
1514         // OffsetBot is used to reference array's element,
1515         // always add reference to NULL to all Field nodes since we don't
1516         // known which element is referenced.
1517         if (add_edge(field, null_obj)) {
1518           // New edge was added
1519           new_edges++;
1520           add_field_uses_to_worklist(field->as_Field());
1521           visited_bottom_offset = true;
1522         }
1523       }
1524     } else {
1525       // Check only oop fields.
1526       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1527       if (adr_type->isa_rawptr()) {
1528 #ifdef ASSERT
1529         // Raw pointers are used for initializing stores so skip it
1530         // since it should be recorded already
1531         Node* base = get_addp_base(field->ideal_node());
1532         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1533                (base->in(0) == alloc),"unexpected pointer type");
1534 #endif
1535         continue;
1536       }
1537       if (!offsets_worklist.contains(offset)) {
1538         offsets_worklist.append(offset);
1539         Node* value = NULL;
1540         if (ini != NULL) {
1541           // StoreP::memory_type() == T_ADDRESS
1542           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1543           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1544           // Make sure initializing store has the same type as this AddP.
1545           // This AddP may reference non existing field because it is on a
1546           // dead branch of bimorphic call which is not eliminated yet.
1547           if (store != NULL && store->is_Store() &&
1548               store->as_Store()->memory_type() == ft) {
1549             value = store->in(MemNode::ValueIn);
1550 #ifdef ASSERT
1551             if (VerifyConnectionGraph) {
1552               // Verify that AddP already points to all objects the value points to.
1553               PointsToNode* val = ptnode_adr(value->_idx);
1554               assert((val != NULL), "should be processed already");
1555               PointsToNode* missed_obj = NULL;
1556               if (val->is_JavaObject()) {
1557                 if (!field->points_to(val->as_JavaObject())) {
1558                   missed_obj = val;
1559                 }
1560               } else {
1561                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1562                   tty->print_cr("----------init store has invalid value -----");
1563                   store->dump();
1564                   val->dump();
1565                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1566                 }
1567                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1568                   PointsToNode* obj = j.get();
1569                   if (obj->is_JavaObject()) {
1570                     if (!field->points_to(obj->as_JavaObject())) {
1571                       missed_obj = obj;
1572                       break;
1573                     }
1574                   }
1575                 }
1576               }
1577               if (missed_obj != NULL) {
1578                 tty->print_cr("----------field---------------------------------");
1579                 field->dump();
1580                 tty->print_cr("----------missed referernce to object-----------");
1581                 missed_obj->dump();
1582                 tty->print_cr("----------object referernced by init store -----");
1583                 store->dump();
1584                 val->dump();
1585                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1586               }
1587             }
1588 #endif
1589           } else {
1590             // There could be initializing stores which follow allocation.
1591             // For example, a volatile field store is not collected
1592             // by Initialize node.
1593             //
1594             // Need to check for dependent loads to separate such stores from
1595             // stores which follow loads. For now, add initial value NULL so
1596             // that compare pointers optimization works correctly.
1597           }
1598         }
1599         if (value == NULL) {
1600           // A field's initializing value was not recorded. Add NULL.
1601           if (add_edge(field, null_obj)) {
1602             // New edge was added
1603             new_edges++;
1604             add_field_uses_to_worklist(field->as_Field());
1605           }
1606         }
1607       }
1608     }
1609   }
1610   return new_edges;
1611 }
1612 
1613 // Adjust scalar_replaceable state after Connection Graph is built.
1614 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1615   // Search for non-escaping objects which are not scalar replaceable
1616   // and mark them to propagate the state to referenced objects.
1617 
1618   // 1. An object is not scalar replaceable if the field into which it is
1619   // stored has unknown offset (stored into unknown element of an array).
1620   //
1621   for (UseIterator i(jobj); i.has_next(); i.next()) {
1622     PointsToNode* use = i.get();
1623     assert(!use->is_Arraycopy(), "sanity");
1624     if (use->is_Field()) {
1625       FieldNode* field = use->as_Field();
1626       assert(field->is_oop() && field->scalar_replaceable() &&
1627              field->fields_escape_state() == PointsToNode::NoEscape, "sanity");
1628       if (field->offset() == Type::OffsetBot) {
1629         jobj->set_scalar_replaceable(false);
1630         return;
1631       }
1632       // 2. An object is not scalar replaceable if the field into which it is
1633       // stored has multiple bases one of which is null.
1634       if (field->base_count() > 1) {
1635         for (BaseIterator i(field); i.has_next(); i.next()) {
1636           PointsToNode* base = i.get();
1637           if (base == null_obj) {
1638             jobj->set_scalar_replaceable(false);
1639             return;
1640           }
1641         }
1642       }
1643     }
1644     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1645     // 3. An object is not scalar replaceable if it is merged with other objects.
1646     for (EdgeIterator j(use); j.has_next(); j.next()) {
1647       PointsToNode* ptn = j.get();
1648       if (ptn->is_JavaObject() && ptn != jobj) {
1649         // Mark all objects.
1650         jobj->set_scalar_replaceable(false);
1651          ptn->set_scalar_replaceable(false);
1652       }
1653     }
1654     if (!jobj->scalar_replaceable()) {
1655       return;
1656     }
1657   }
1658 
1659   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1660     // Non-escaping object node should point only to field nodes.
1661     FieldNode* field = j.get()->as_Field();
1662     int offset = field->as_Field()->offset();
1663 
1664     // 4. An object is not scalar replaceable if it has a field with unknown
1665     // offset (array's element is accessed in loop).
1666     if (offset == Type::OffsetBot) {
1667       jobj->set_scalar_replaceable(false);
1668       return;
1669     }
1670     // 5. Currently an object is not scalar replaceable if a LoadStore node
1671     // access its field since the field value is unknown after it.
1672     //
1673     Node* n = field->ideal_node();
1674     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1675       if (n->fast_out(i)->is_LoadStore()) {
1676         jobj->set_scalar_replaceable(false);
1677         return;
1678       }
1679     }
1680 
1681     // 6. Or the address may point to more then one object. This may produce
1682     // the false positive result (set not scalar replaceable)
1683     // since the flow-insensitive escape analysis can't separate
1684     // the case when stores overwrite the field's value from the case
1685     // when stores happened on different control branches.
1686     //
1687     // Note: it will disable scalar replacement in some cases:
1688     //
1689     //    Point p[] = new Point[1];
1690     //    p[0] = new Point(); // Will be not scalar replaced
1691     //
1692     // but it will save us from incorrect optimizations in next cases:
1693     //
1694     //    Point p[] = new Point[1];
1695     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1696     //
1697     if (field->base_count() > 1) {
1698       for (BaseIterator i(field); i.has_next(); i.next()) {
1699         PointsToNode* base = i.get();
1700         // Don't take into account LocalVar nodes which
1701         // may point to only one object which should be also
1702         // this field's base by now.
1703         if (base->is_JavaObject() && base != jobj) {
1704           // Mark all bases.
1705           jobj->set_scalar_replaceable(false);
1706           base->set_scalar_replaceable(false);
1707         }
1708       }
1709     }
1710   }
1711 }
1712 
1713 #ifdef ASSERT
1714 void ConnectionGraph::verify_connection_graph(
1715                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1716                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1717                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1718                          GrowableArray<Node*>& addp_worklist) {
1719   // Verify that graph is complete - no new edges could be added.
1720   int java_objects_length = java_objects_worklist.length();
1721   int non_escaped_length  = non_escaped_worklist.length();
1722   int new_edges = 0;
1723   for (int next = 0; next < java_objects_length; ++next) {
1724     JavaObjectNode* ptn = java_objects_worklist.at(next);
1725     new_edges += add_java_object_edges(ptn, true);
1726   }
1727   assert(new_edges == 0, "graph was not complete");
1728   // Verify that escape state is final.
1729   int length = non_escaped_worklist.length();
1730   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1731   assert((non_escaped_length == non_escaped_worklist.length()) &&
1732          (non_escaped_length == length) &&
1733          (_worklist.length() == 0), "escape state was not final");
1734 
1735   // Verify fields information.
1736   int addp_length = addp_worklist.length();
1737   for (int next = 0; next < addp_length; ++next ) {
1738     Node* n = addp_worklist.at(next);
1739     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1740     if (field->is_oop()) {
1741       // Verify that field has all bases
1742       Node* base = get_addp_base(n);
1743       PointsToNode* ptn = ptnode_adr(base->_idx);
1744       if (ptn->is_JavaObject()) {
1745         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1746       } else {
1747         assert(ptn->is_LocalVar(), "sanity");
1748         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1749           PointsToNode* e = i.get();
1750           if (e->is_JavaObject()) {
1751             assert(field->has_base(e->as_JavaObject()), "sanity");
1752           }
1753         }
1754       }
1755       // Verify that all fields have initializing values.
1756       if (field->edge_count() == 0) {
1757         tty->print_cr("----------field does not have references----------");
1758         field->dump();
1759         for (BaseIterator i(field); i.has_next(); i.next()) {
1760           PointsToNode* base = i.get();
1761           tty->print_cr("----------field has next base---------------------");
1762           base->dump();
1763           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1764             tty->print_cr("----------base has fields-------------------------");
1765             for (EdgeIterator j(base); j.has_next(); j.next()) {
1766               j.get()->dump();
1767             }
1768             tty->print_cr("----------base has references---------------------");
1769             for (UseIterator j(base); j.has_next(); j.next()) {
1770               j.get()->dump();
1771             }
1772           }
1773         }
1774         for (UseIterator i(field); i.has_next(); i.next()) {
1775           i.get()->dump();
1776         }
1777         assert(field->edge_count() > 0, "sanity");
1778       }
1779     }
1780   }
1781 }
1782 #endif
1783 
1784 // Optimize ideal graph.
1785 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1786                                            GrowableArray<Node*>& storestore_worklist) {
1787   Compile* C = _compile;
1788   PhaseIterGVN* igvn = _igvn;
1789   if (EliminateLocks) {
1790     // Mark locks before changing ideal graph.
1791     int cnt = C->macro_count();
1792     for( int i=0; i < cnt; i++ ) {
1793       Node *n = C->macro_node(i);
1794       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1795         AbstractLockNode* alock = n->as_AbstractLock();
1796         if (!alock->is_non_esc_obj()) {
1797           if (not_global_escape(alock->obj_node())) {
1798             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1799             // The lock could be marked eliminated by lock coarsening
1800             // code during first IGVN before EA. Replace coarsened flag
1801             // to eliminate all associated locks/unlocks.
1802 #ifdef ASSERT
1803             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1804 #endif
1805             alock->set_non_esc_obj();
1806           }
1807         }
1808       }
1809     }
1810   }
1811 
1812   if (OptimizePtrCompare) {
1813     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1814     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1815     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1816     // Optimize objects compare.
1817     while (ptr_cmp_worklist.length() != 0) {
1818       Node *n = ptr_cmp_worklist.pop();
1819       Node *res = optimize_ptr_compare(n);
1820       if (res != NULL) {
1821 #ifndef PRODUCT
1822         if (PrintOptimizePtrCompare) {
1823           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"));
1824           if (Verbose) {
1825             n->dump(1);
1826           }
1827         }
1828 #endif
1829         igvn->replace_node(n, res);
1830       }
1831     }
1832     // cleanup
1833     if (_pcmp_neq->outcnt() == 0)
1834       igvn->hash_delete(_pcmp_neq);
1835     if (_pcmp_eq->outcnt()  == 0)
1836       igvn->hash_delete(_pcmp_eq);
1837   }
1838 
1839   // For MemBarStoreStore nodes added in library_call.cpp, check
1840   // escape status of associated AllocateNode and optimize out
1841   // MemBarStoreStore node if the allocated object never escapes.
1842   while (storestore_worklist.length() != 0) {
1843     Node *n = storestore_worklist.pop();
1844     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1845     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1846     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1847     if (not_global_escape(alloc)) {
1848       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1849       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1850       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1851       igvn->register_new_node_with_optimizer(mb);
1852       igvn->replace_node(storestore, mb);
1853     }
1854   }
1855 }
1856 
1857 // Optimize objects compare.
1858 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1859   assert(OptimizePtrCompare, "sanity");
1860   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1861   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1862   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1863   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1864   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1865   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1866 
1867   // Check simple cases first.
1868   if (jobj1 != NULL) {
1869     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1870       if (jobj1 == jobj2) {
1871         // Comparing the same not escaping object.
1872         return _pcmp_eq;
1873       }
1874       Node* obj = jobj1->ideal_node();
1875       // Comparing not escaping allocation.
1876       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1877           !ptn2->points_to(jobj1)) {
1878         return _pcmp_neq; // This includes nullness check.
1879       }
1880     }
1881   }
1882   if (jobj2 != NULL) {
1883     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1884       Node* obj = jobj2->ideal_node();
1885       // Comparing not escaping allocation.
1886       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1887           !ptn1->points_to(jobj2)) {
1888         return _pcmp_neq; // This includes nullness check.
1889       }
1890     }
1891   }
1892   if (jobj1 != NULL && jobj1 != phantom_obj &&
1893       jobj2 != NULL && jobj2 != phantom_obj &&
1894       jobj1->ideal_node()->is_Con() &&
1895       jobj2->ideal_node()->is_Con()) {
1896     // Klass or String constants compare. Need to be careful with
1897     // compressed pointers - compare types of ConN and ConP instead of nodes.
1898     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1899     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1900     if (t1->make_ptr() == t2->make_ptr()) {
1901       return _pcmp_eq;
1902     } else {
1903       return _pcmp_neq;
1904     }
1905   }
1906   if (ptn1->meet(ptn2)) {
1907     return NULL; // Sets are not disjoint
1908   }
1909 
1910   // Sets are disjoint.
1911   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1912   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1913   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1914   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1915   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1916       set2_has_unknown_ptr && set1_has_null_ptr) {
1917     // Check nullness of unknown object.
1918     return NULL;
1919   }
1920 
1921   // Disjointness by itself is not sufficient since
1922   // alias analysis is not complete for escaped objects.
1923   // Disjoint sets are definitely unrelated only when
1924   // at least one set has only not escaping allocations.
1925   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1926     if (ptn1->non_escaping_allocation()) {
1927       return _pcmp_neq;
1928     }
1929   }
1930   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1931     if (ptn2->non_escaping_allocation()) {
1932       return _pcmp_neq;
1933     }
1934   }
1935   return NULL;
1936 }
1937 
1938 // Connection Graph constuction functions.
1939 
1940 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1941   PointsToNode* ptadr = _nodes.at(n->_idx);
1942   if (ptadr != NULL) {
1943     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1944     return;
1945   }
1946   Compile* C = _compile;
1947   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
1948   _nodes.at_put(n->_idx, ptadr);
1949 }
1950 
1951 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
1952   PointsToNode* ptadr = _nodes.at(n->_idx);
1953   if (ptadr != NULL) {
1954     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
1955     return;
1956   }
1957   Compile* C = _compile;
1958   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
1959   _nodes.at_put(n->_idx, ptadr);
1960 }
1961 
1962 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
1963   PointsToNode* ptadr = _nodes.at(n->_idx);
1964   if (ptadr != NULL) {
1965     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
1966     return;
1967   }
1968   bool unsafe = false;
1969   bool is_oop = is_oop_field(n, offset, &unsafe);
1970   if (unsafe) {
1971     es = PointsToNode::GlobalEscape;
1972   }
1973   Compile* C = _compile;
1974   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
1975   _nodes.at_put(n->_idx, field);
1976 }
1977 
1978 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
1979                                     PointsToNode* src, PointsToNode* dst) {
1980   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
1981   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
1982   PointsToNode* ptadr = _nodes.at(n->_idx);
1983   if (ptadr != NULL) {
1984     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
1985     return;
1986   }
1987   Compile* C = _compile;
1988   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
1989   _nodes.at_put(n->_idx, ptadr);
1990   // Add edge from arraycopy node to source object.
1991   (void)add_edge(ptadr, src);
1992   src->set_arraycopy_src();
1993   // Add edge from destination object to arraycopy node.
1994   (void)add_edge(dst, ptadr);
1995   dst->set_arraycopy_dst();
1996 }
1997 
1998 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
1999   const Type* adr_type = n->as_AddP()->bottom_type();
2000   BasicType bt = T_INT;
2001   if (offset == Type::OffsetBot) {
2002     // Check only oop fields.
2003     if (!adr_type->isa_aryptr() ||
2004         (adr_type->isa_aryptr()->klass() == NULL) ||
2005          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2006       // OffsetBot is used to reference array's element. Ignore first AddP.
2007       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2008         bt = T_OBJECT;
2009       }
2010     }
2011   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2012     if (adr_type->isa_instptr()) {
2013       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2014       if (field != NULL) {
2015         bt = field->layout_type();
2016       } else {
2017         // Check for unsafe oop field access
2018         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2019           int opcode = n->fast_out(i)->Opcode();
2020           if (opcode == Op_StoreP          || opcode == Op_StoreN ||
2021               opcode == Op_LoadP           || opcode == Op_LoadN  ||
2022               opcode == Op_GetAndSetP      || opcode == Op_GetAndSetN ||
2023               opcode == Op_CompareAndSwapP || opcode == Op_CompareAndSwapN) {
2024             bt = T_OBJECT;
2025             (*unsafe) = true;
2026             break;
2027           }
2028         }
2029       }
2030     } else if (adr_type->isa_aryptr()) {
2031       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2032         // Ignore array length load.
2033       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2034         // Ignore first AddP.
2035       } else {
2036         const Type* elemtype = adr_type->isa_aryptr()->elem();
2037         bt = elemtype->array_element_basic_type();
2038       }
2039     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2040       // Allocation initialization, ThreadLocal field access, unsafe access
2041       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2042         int opcode = n->fast_out(i)->Opcode();
2043         if (opcode == Op_StoreP          || opcode == Op_StoreN ||
2044             opcode == Op_LoadP           || opcode == Op_LoadN  ||
2045             opcode == Op_GetAndSetP      || opcode == Op_GetAndSetN ||
2046             opcode == Op_CompareAndSwapP || opcode == Op_CompareAndSwapN) {
2047           bt = T_OBJECT;
2048           break;
2049         }
2050       }
2051     }
2052   }
2053   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2054 }
2055 
2056 // Returns unique pointed java object or NULL.
2057 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2058   assert(!_collecting, "should not call when contructed graph");
2059   // If the node was created after the escape computation we can't answer.
2060   uint idx = n->_idx;
2061   if (idx >= nodes_size()) {
2062     return NULL;
2063   }
2064   PointsToNode* ptn = ptnode_adr(idx);
2065   if (ptn == NULL) {
2066     return NULL;
2067   }
2068   if (ptn->is_JavaObject()) {
2069     return ptn->as_JavaObject();
2070   }
2071   assert(ptn->is_LocalVar(), "sanity");
2072   // Check all java objects it points to.
2073   JavaObjectNode* jobj = NULL;
2074   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2075     PointsToNode* e = i.get();
2076     if (e->is_JavaObject()) {
2077       if (jobj == NULL) {
2078         jobj = e->as_JavaObject();
2079       } else if (jobj != e) {
2080         return NULL;
2081       }
2082     }
2083   }
2084   return jobj;
2085 }
2086 
2087 // Return true if this node points only to non-escaping allocations.
2088 bool PointsToNode::non_escaping_allocation() {
2089   if (is_JavaObject()) {
2090     Node* n = ideal_node();
2091     if (n->is_Allocate() || n->is_CallStaticJava()) {
2092       return (escape_state() == PointsToNode::NoEscape);
2093     } else {
2094       return false;
2095     }
2096   }
2097   assert(is_LocalVar(), "sanity");
2098   // Check all java objects it points to.
2099   for (EdgeIterator i(this); i.has_next(); i.next()) {
2100     PointsToNode* e = i.get();
2101     if (e->is_JavaObject()) {
2102       Node* n = e->ideal_node();
2103       if ((e->escape_state() != PointsToNode::NoEscape) ||
2104           !(n->is_Allocate() || n->is_CallStaticJava())) {
2105         return false;
2106       }
2107     }
2108   }
2109   return true;
2110 }
2111 
2112 // Return true if we know the node does not escape globally.
2113 bool ConnectionGraph::not_global_escape(Node *n) {
2114   assert(!_collecting, "should not call during graph construction");
2115   // If the node was created after the escape computation we can't answer.
2116   uint idx = n->_idx;
2117   if (idx >= nodes_size()) {
2118     return false;
2119   }
2120   PointsToNode* ptn = ptnode_adr(idx);
2121   if (ptn == NULL) {
2122     return false; // not in congraph (e.g. ConI)
2123   }
2124   PointsToNode::EscapeState es = ptn->escape_state();
2125   // If we have already computed a value, return it.
2126   if (es >= PointsToNode::GlobalEscape)
2127     return false;
2128   if (ptn->is_JavaObject()) {
2129     return true; // (es < PointsToNode::GlobalEscape);
2130   }
2131   assert(ptn->is_LocalVar(), "sanity");
2132   // Check all java objects it points to.
2133   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2134     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2135       return false;
2136   }
2137   return true;
2138 }
2139 
2140 
2141 // Helper functions
2142 
2143 // Return true if this node points to specified node or nodes it points to.
2144 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2145   if (is_JavaObject()) {
2146     return (this == ptn);
2147   }
2148   assert(is_LocalVar() || is_Field(), "sanity");
2149   for (EdgeIterator i(this); i.has_next(); i.next()) {
2150     if (i.get() == ptn)
2151       return true;
2152   }
2153   return false;
2154 }
2155 
2156 // Return true if one node points to an other.
2157 bool PointsToNode::meet(PointsToNode* ptn) {
2158   if (this == ptn) {
2159     return true;
2160   } else if (ptn->is_JavaObject()) {
2161     return this->points_to(ptn->as_JavaObject());
2162   } else if (this->is_JavaObject()) {
2163     return ptn->points_to(this->as_JavaObject());
2164   }
2165   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2166   int ptn_count =  ptn->edge_count();
2167   for (EdgeIterator i(this); i.has_next(); i.next()) {
2168     PointsToNode* this_e = i.get();
2169     for (int j = 0; j < ptn_count; j++) {
2170       if (this_e == ptn->edge(j))
2171         return true;
2172     }
2173   }
2174   return false;
2175 }
2176 
2177 #ifdef ASSERT
2178 // Return true if bases point to this java object.
2179 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2180   for (BaseIterator i(this); i.has_next(); i.next()) {
2181     if (i.get() == jobj)
2182       return true;
2183   }
2184   return false;
2185 }
2186 #endif
2187 
2188 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2189   const Type *adr_type = phase->type(adr);
2190   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2191       adr->in(AddPNode::Address)->is_Proj() &&
2192       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2193     // We are computing a raw address for a store captured by an Initialize
2194     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2195     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2196     assert(offs != Type::OffsetBot ||
2197            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2198            "offset must be a constant or it is initialization of array");
2199     return offs;
2200   }
2201   const TypePtr *t_ptr = adr_type->isa_ptr();
2202   assert(t_ptr != NULL, "must be a pointer type");
2203   return t_ptr->offset();
2204 }
2205 
2206 Node* ConnectionGraph::get_addp_base(Node *addp) {
2207   assert(addp->is_AddP(), "must be AddP");
2208   //
2209   // AddP cases for Base and Address inputs:
2210   // case #1. Direct object's field reference:
2211   //     Allocate
2212   //       |
2213   //     Proj #5 ( oop result )
2214   //       |
2215   //     CheckCastPP (cast to instance type)
2216   //      | |
2217   //     AddP  ( base == address )
2218   //
2219   // case #2. Indirect object's field reference:
2220   //      Phi
2221   //       |
2222   //     CastPP (cast to instance type)
2223   //      | |
2224   //     AddP  ( base == address )
2225   //
2226   // case #3. Raw object's field reference for Initialize node:
2227   //      Allocate
2228   //        |
2229   //      Proj #5 ( oop result )
2230   //  top   |
2231   //     \  |
2232   //     AddP  ( base == top )
2233   //
2234   // case #4. Array's element reference:
2235   //   {CheckCastPP | CastPP}
2236   //     |  | |
2237   //     |  AddP ( array's element offset )
2238   //     |  |
2239   //     AddP ( array's offset )
2240   //
2241   // case #5. Raw object's field reference for arraycopy stub call:
2242   //          The inline_native_clone() case when the arraycopy stub is called
2243   //          after the allocation before Initialize and CheckCastPP nodes.
2244   //      Allocate
2245   //        |
2246   //      Proj #5 ( oop result )
2247   //       | |
2248   //       AddP  ( base == address )
2249   //
2250   // case #6. Constant Pool, ThreadLocal, CastX2P or
2251   //          Raw object's field reference:
2252   //      {ConP, ThreadLocal, CastX2P, raw Load}
2253   //  top   |
2254   //     \  |
2255   //     AddP  ( base == top )
2256   //
2257   // case #7. Klass's field reference.
2258   //      LoadKlass
2259   //       | |
2260   //       AddP  ( base == address )
2261   //
2262   // case #8. narrow Klass's field reference.
2263   //      LoadNKlass
2264   //       |
2265   //      DecodeN
2266   //       | |
2267   //       AddP  ( base == address )
2268   //
2269   Node *base = addp->in(AddPNode::Base);
2270   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2271     base = addp->in(AddPNode::Address);
2272     while (base->is_AddP()) {
2273       // Case #6 (unsafe access) may have several chained AddP nodes.
2274       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2275       base = base->in(AddPNode::Address);
2276     }
2277     Node* uncast_base = base->uncast();
2278     int opcode = uncast_base->Opcode();
2279     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2280            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2281            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2282            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2283   }
2284   return base;
2285 }
2286 
2287 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2288   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2289   Node* addp2 = addp->raw_out(0);
2290   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2291       addp2->in(AddPNode::Base) == n &&
2292       addp2->in(AddPNode::Address) == addp) {
2293     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2294     //
2295     // Find array's offset to push it on worklist first and
2296     // as result process an array's element offset first (pushed second)
2297     // to avoid CastPP for the array's offset.
2298     // Otherwise the inserted CastPP (LocalVar) will point to what
2299     // the AddP (Field) points to. Which would be wrong since
2300     // the algorithm expects the CastPP has the same point as
2301     // as AddP's base CheckCastPP (LocalVar).
2302     //
2303     //    ArrayAllocation
2304     //     |
2305     //    CheckCastPP
2306     //     |
2307     //    memProj (from ArrayAllocation CheckCastPP)
2308     //     |  ||
2309     //     |  ||   Int (element index)
2310     //     |  ||    |   ConI (log(element size))
2311     //     |  ||    |   /
2312     //     |  ||   LShift
2313     //     |  ||  /
2314     //     |  AddP (array's element offset)
2315     //     |  |
2316     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2317     //     | / /
2318     //     AddP (array's offset)
2319     //      |
2320     //     Load/Store (memory operation on array's element)
2321     //
2322     return addp2;
2323   }
2324   return NULL;
2325 }
2326 
2327 //
2328 // Adjust the type and inputs of an AddP which computes the
2329 // address of a field of an instance
2330 //
2331 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2332   PhaseGVN* igvn = _igvn;
2333   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2334   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2335   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2336   if (t == NULL) {
2337     // We are computing a raw address for a store captured by an Initialize
2338     // compute an appropriate address type (cases #3 and #5).
2339     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2340     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2341     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2342     assert(offs != Type::OffsetBot, "offset must be a constant");
2343     t = base_t->add_offset(offs)->is_oopptr();
2344   }
2345   int inst_id =  base_t->instance_id();
2346   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2347                              "old type must be non-instance or match new type");
2348 
2349   // The type 't' could be subclass of 'base_t'.
2350   // As result t->offset() could be large then base_t's size and it will
2351   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2352   // constructor verifies correctness of the offset.
2353   //
2354   // It could happened on subclass's branch (from the type profiling
2355   // inlining) which was not eliminated during parsing since the exactness
2356   // of the allocation type was not propagated to the subclass type check.
2357   //
2358   // Or the type 't' could be not related to 'base_t' at all.
2359   // It could happened when CHA type is different from MDO type on a dead path
2360   // (for example, from instanceof check) which is not collapsed during parsing.
2361   //
2362   // Do nothing for such AddP node and don't process its users since
2363   // this code branch will go away.
2364   //
2365   if (!t->is_known_instance() &&
2366       !base_t->klass()->is_subtype_of(t->klass())) {
2367      return false; // bail out
2368   }
2369   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2370   // Do NOT remove the next line: ensure a new alias index is allocated
2371   // for the instance type. Note: C++ will not remove it since the call
2372   // has side effect.
2373   int alias_idx = _compile->get_alias_index(tinst);
2374   igvn->set_type(addp, tinst);
2375   // record the allocation in the node map
2376   set_map(addp, get_map(base->_idx));
2377   // Set addp's Base and Address to 'base'.
2378   Node *abase = addp->in(AddPNode::Base);
2379   Node *adr   = addp->in(AddPNode::Address);
2380   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2381       adr->in(0)->_idx == (uint)inst_id) {
2382     // Skip AddP cases #3 and #5.
2383   } else {
2384     assert(!abase->is_top(), "sanity"); // AddP case #3
2385     if (abase != base) {
2386       igvn->hash_delete(addp);
2387       addp->set_req(AddPNode::Base, base);
2388       if (abase == adr) {
2389         addp->set_req(AddPNode::Address, base);
2390       } else {
2391         // AddP case #4 (adr is array's element offset AddP node)
2392 #ifdef ASSERT
2393         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2394         assert(adr->is_AddP() && atype != NULL &&
2395                atype->instance_id() == inst_id, "array's element offset should be processed first");
2396 #endif
2397       }
2398       igvn->hash_insert(addp);
2399     }
2400   }
2401   // Put on IGVN worklist since at least addp's type was changed above.
2402   record_for_optimizer(addp);
2403   return true;
2404 }
2405 
2406 //
2407 // Create a new version of orig_phi if necessary. Returns either the newly
2408 // created phi or an existing phi.  Sets create_new to indicate whether a new
2409 // phi was created.  Cache the last newly created phi in the node map.
2410 //
2411 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2412   Compile *C = _compile;
2413   PhaseGVN* igvn = _igvn;
2414   new_created = false;
2415   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2416   // nothing to do if orig_phi is bottom memory or matches alias_idx
2417   if (phi_alias_idx == alias_idx) {
2418     return orig_phi;
2419   }
2420   // Have we recently created a Phi for this alias index?
2421   PhiNode *result = get_map_phi(orig_phi->_idx);
2422   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2423     return result;
2424   }
2425   // Previous check may fail when the same wide memory Phi was split into Phis
2426   // for different memory slices. Search all Phis for this region.
2427   if (result != NULL) {
2428     Node* region = orig_phi->in(0);
2429     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2430       Node* phi = region->fast_out(i);
2431       if (phi->is_Phi() &&
2432           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2433         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2434         return phi->as_Phi();
2435       }
2436     }
2437   }
2438   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2439     if (C->do_escape_analysis() == true && !C->failing()) {
2440       // Retry compilation without escape analysis.
2441       // If this is the first failure, the sentinel string will "stick"
2442       // to the Compile object, and the C2Compiler will see it and retry.
2443       C->record_failure(C2Compiler::retry_no_escape_analysis());
2444     }
2445     return NULL;
2446   }
2447   orig_phi_worklist.append_if_missing(orig_phi);
2448   const TypePtr *atype = C->get_adr_type(alias_idx);
2449   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2450   C->copy_node_notes_to(result, orig_phi);
2451   igvn->set_type(result, result->bottom_type());
2452   record_for_optimizer(result);
2453   set_map(orig_phi, result);
2454   new_created = true;
2455   return result;
2456 }
2457 
2458 //
2459 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2460 // specified alias index.
2461 //
2462 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2463   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2464   Compile *C = _compile;
2465   PhaseGVN* igvn = _igvn;
2466   bool new_phi_created;
2467   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2468   if (!new_phi_created) {
2469     return result;
2470   }
2471   GrowableArray<PhiNode *>  phi_list;
2472   GrowableArray<uint>  cur_input;
2473   PhiNode *phi = orig_phi;
2474   uint idx = 1;
2475   bool finished = false;
2476   while(!finished) {
2477     while (idx < phi->req()) {
2478       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2479       if (mem != NULL && mem->is_Phi()) {
2480         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2481         if (new_phi_created) {
2482           // found an phi for which we created a new split, push current one on worklist and begin
2483           // processing new one
2484           phi_list.push(phi);
2485           cur_input.push(idx);
2486           phi = mem->as_Phi();
2487           result = newphi;
2488           idx = 1;
2489           continue;
2490         } else {
2491           mem = newphi;
2492         }
2493       }
2494       if (C->failing()) {
2495         return NULL;
2496       }
2497       result->set_req(idx++, mem);
2498     }
2499 #ifdef ASSERT
2500     // verify that the new Phi has an input for each input of the original
2501     assert( phi->req() == result->req(), "must have same number of inputs.");
2502     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2503 #endif
2504     // Check if all new phi's inputs have specified alias index.
2505     // Otherwise use old phi.
2506     for (uint i = 1; i < phi->req(); i++) {
2507       Node* in = result->in(i);
2508       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2509     }
2510     // we have finished processing a Phi, see if there are any more to do
2511     finished = (phi_list.length() == 0 );
2512     if (!finished) {
2513       phi = phi_list.pop();
2514       idx = cur_input.pop();
2515       PhiNode *prev_result = get_map_phi(phi->_idx);
2516       prev_result->set_req(idx++, result);
2517       result = prev_result;
2518     }
2519   }
2520   return result;
2521 }
2522 
2523 //
2524 // The next methods are derived from methods in MemNode.
2525 //
2526 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2527   Node *mem = mmem;
2528   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2529   // means an array I have not precisely typed yet.  Do not do any
2530   // alias stuff with it any time soon.
2531   if (toop->base() != Type::AnyPtr &&
2532       !(toop->klass() != NULL &&
2533         toop->klass()->is_java_lang_Object() &&
2534         toop->offset() == Type::OffsetBot)) {
2535     mem = mmem->memory_at(alias_idx);
2536     // Update input if it is progress over what we have now
2537   }
2538   return mem;
2539 }
2540 
2541 //
2542 // Move memory users to their memory slices.
2543 //
2544 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2545   Compile* C = _compile;
2546   PhaseGVN* igvn = _igvn;
2547   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2548   assert(tp != NULL, "ptr type");
2549   int alias_idx = C->get_alias_index(tp);
2550   int general_idx = C->get_general_index(alias_idx);
2551 
2552   // Move users first
2553   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2554     Node* use = n->fast_out(i);
2555     if (use->is_MergeMem()) {
2556       MergeMemNode* mmem = use->as_MergeMem();
2557       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2558       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2559         continue; // Nothing to do
2560       }
2561       // Replace previous general reference to mem node.
2562       uint orig_uniq = C->unique();
2563       Node* m = find_inst_mem(n, general_idx, orig_phis);
2564       assert(orig_uniq == C->unique(), "no new nodes");
2565       mmem->set_memory_at(general_idx, m);
2566       --imax;
2567       --i;
2568     } else if (use->is_MemBar()) {
2569       assert(!use->is_Initialize(), "initializing stores should not be moved");
2570       if (use->req() > MemBarNode::Precedent &&
2571           use->in(MemBarNode::Precedent) == n) {
2572         // Don't move related membars.
2573         record_for_optimizer(use);
2574         continue;
2575       }
2576       tp = use->as_MemBar()->adr_type()->isa_ptr();
2577       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2578           alias_idx == general_idx) {
2579         continue; // Nothing to do
2580       }
2581       // Move to general memory slice.
2582       uint orig_uniq = C->unique();
2583       Node* m = find_inst_mem(n, general_idx, orig_phis);
2584       assert(orig_uniq == C->unique(), "no new nodes");
2585       igvn->hash_delete(use);
2586       imax -= use->replace_edge(n, m);
2587       igvn->hash_insert(use);
2588       record_for_optimizer(use);
2589       --i;
2590 #ifdef ASSERT
2591     } else if (use->is_Mem()) {
2592       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2593         // Don't move related cardmark.
2594         continue;
2595       }
2596       // Memory nodes should have new memory input.
2597       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2598       assert(tp != NULL, "ptr type");
2599       int idx = C->get_alias_index(tp);
2600       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2601              "Following memory nodes should have new memory input or be on the same memory slice");
2602     } else if (use->is_Phi()) {
2603       // Phi nodes should be split and moved already.
2604       tp = use->as_Phi()->adr_type()->isa_ptr();
2605       assert(tp != NULL, "ptr type");
2606       int idx = C->get_alias_index(tp);
2607       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2608     } else {
2609       use->dump();
2610       assert(false, "should not be here");
2611 #endif
2612     }
2613   }
2614 }
2615 
2616 //
2617 // Search memory chain of "mem" to find a MemNode whose address
2618 // is the specified alias index.
2619 //
2620 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2621   if (orig_mem == NULL)
2622     return orig_mem;
2623   Compile* C = _compile;
2624   PhaseGVN* igvn = _igvn;
2625   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2626   bool is_instance = (toop != NULL) && toop->is_known_instance();
2627   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2628   Node *prev = NULL;
2629   Node *result = orig_mem;
2630   while (prev != result) {
2631     prev = result;
2632     if (result == start_mem)
2633       break;  // hit one of our sentinels
2634     if (result->is_Mem()) {
2635       const Type *at = igvn->type(result->in(MemNode::Address));
2636       if (at == Type::TOP)
2637         break; // Dead
2638       assert (at->isa_ptr() != NULL, "pointer type required.");
2639       int idx = C->get_alias_index(at->is_ptr());
2640       if (idx == alias_idx)
2641         break; // Found
2642       if (!is_instance && (at->isa_oopptr() == NULL ||
2643                            !at->is_oopptr()->is_known_instance())) {
2644         break; // Do not skip store to general memory slice.
2645       }
2646       result = result->in(MemNode::Memory);
2647     }
2648     if (!is_instance)
2649       continue;  // don't search further for non-instance types
2650     // skip over a call which does not affect this memory slice
2651     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2652       Node *proj_in = result->in(0);
2653       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2654         break;  // hit one of our sentinels
2655       } else if (proj_in->is_Call()) {
2656         CallNode *call = proj_in->as_Call();
2657         if (!call->may_modify(toop, igvn)) {
2658           result = call->in(TypeFunc::Memory);
2659         }
2660       } else if (proj_in->is_Initialize()) {
2661         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2662         // Stop if this is the initialization for the object instance which
2663         // which contains this memory slice, otherwise skip over it.
2664         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2665           result = proj_in->in(TypeFunc::Memory);
2666         }
2667       } else if (proj_in->is_MemBar()) {
2668         result = proj_in->in(TypeFunc::Memory);
2669       }
2670     } else if (result->is_MergeMem()) {
2671       MergeMemNode *mmem = result->as_MergeMem();
2672       result = step_through_mergemem(mmem, alias_idx, toop);
2673       if (result == mmem->base_memory()) {
2674         // Didn't find instance memory, search through general slice recursively.
2675         result = mmem->memory_at(C->get_general_index(alias_idx));
2676         result = find_inst_mem(result, alias_idx, orig_phis);
2677         if (C->failing()) {
2678           return NULL;
2679         }
2680         mmem->set_memory_at(alias_idx, result);
2681       }
2682     } else if (result->is_Phi() &&
2683                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2684       Node *un = result->as_Phi()->unique_input(igvn);
2685       if (un != NULL) {
2686         orig_phis.append_if_missing(result->as_Phi());
2687         result = un;
2688       } else {
2689         break;
2690       }
2691     } else if (result->is_ClearArray()) {
2692       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2693         // Can not bypass initialization of the instance
2694         // we are looking for.
2695         break;
2696       }
2697       // Otherwise skip it (the call updated 'result' value).
2698     } else if (result->Opcode() == Op_SCMemProj) {
2699       Node* mem = result->in(0);
2700       Node* adr = NULL;
2701       if (mem->is_LoadStore()) {
2702         adr = mem->in(MemNode::Address);
2703       } else {
2704         assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
2705         adr = mem->in(3); // Memory edge corresponds to destination array
2706       }
2707       const Type *at = igvn->type(adr);
2708       if (at != Type::TOP) {
2709         assert (at->isa_ptr() != NULL, "pointer type required.");
2710         int idx = C->get_alias_index(at->is_ptr());
2711         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
2712         break;
2713       }
2714       result = mem->in(MemNode::Memory);
2715     }
2716   }
2717   if (result->is_Phi()) {
2718     PhiNode *mphi = result->as_Phi();
2719     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2720     const TypePtr *t = mphi->adr_type();
2721     if (!is_instance) {
2722       // Push all non-instance Phis on the orig_phis worklist to update inputs
2723       // during Phase 4 if needed.
2724       orig_phis.append_if_missing(mphi);
2725     } else if (C->get_alias_index(t) != alias_idx) {
2726       // Create a new Phi with the specified alias index type.
2727       result = split_memory_phi(mphi, alias_idx, orig_phis);
2728     }
2729   }
2730   // the result is either MemNode, PhiNode, InitializeNode.
2731   return result;
2732 }
2733 
2734 //
2735 //  Convert the types of unescaped object to instance types where possible,
2736 //  propagate the new type information through the graph, and update memory
2737 //  edges and MergeMem inputs to reflect the new type.
2738 //
2739 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2740 //  The processing is done in 4 phases:
2741 //
2742 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2743 //            types for the CheckCastPP for allocations where possible.
2744 //            Propagate the the new types through users as follows:
2745 //               casts and Phi:  push users on alloc_worklist
2746 //               AddP:  cast Base and Address inputs to the instance type
2747 //                      push any AddP users on alloc_worklist and push any memnode
2748 //                      users onto memnode_worklist.
2749 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2750 //            search the Memory chain for a store with the appropriate type
2751 //            address type.  If a Phi is found, create a new version with
2752 //            the appropriate memory slices from each of the Phi inputs.
2753 //            For stores, process the users as follows:
2754 //               MemNode:  push on memnode_worklist
2755 //               MergeMem: push on mergemem_worklist
2756 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2757 //            moving the first node encountered of each  instance type to the
2758 //            the input corresponding to its alias index.
2759 //            appropriate memory slice.
2760 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2761 //
2762 // In the following example, the CheckCastPP nodes are the cast of allocation
2763 // results and the allocation of node 29 is unescaped and eligible to be an
2764 // instance type.
2765 //
2766 // We start with:
2767 //
2768 //     7 Parm #memory
2769 //    10  ConI  "12"
2770 //    19  CheckCastPP   "Foo"
2771 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2772 //    29  CheckCastPP   "Foo"
2773 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2774 //
2775 //    40  StoreP  25   7  20   ... alias_index=4
2776 //    50  StoreP  35  40  30   ... alias_index=4
2777 //    60  StoreP  45  50  20   ... alias_index=4
2778 //    70  LoadP    _  60  30   ... alias_index=4
2779 //    80  Phi     75  50  60   Memory alias_index=4
2780 //    90  LoadP    _  80  30   ... alias_index=4
2781 //   100  LoadP    _  80  20   ... alias_index=4
2782 //
2783 //
2784 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2785 // and creating a new alias index for node 30.  This gives:
2786 //
2787 //     7 Parm #memory
2788 //    10  ConI  "12"
2789 //    19  CheckCastPP   "Foo"
2790 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2791 //    29  CheckCastPP   "Foo"  iid=24
2792 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2793 //
2794 //    40  StoreP  25   7  20   ... alias_index=4
2795 //    50  StoreP  35  40  30   ... alias_index=6
2796 //    60  StoreP  45  50  20   ... alias_index=4
2797 //    70  LoadP    _  60  30   ... alias_index=6
2798 //    80  Phi     75  50  60   Memory alias_index=4
2799 //    90  LoadP    _  80  30   ... alias_index=6
2800 //   100  LoadP    _  80  20   ... alias_index=4
2801 //
2802 // In phase 2, new memory inputs are computed for the loads and stores,
2803 // And a new version of the phi is created.  In phase 4, the inputs to
2804 // node 80 are updated and then the memory nodes are updated with the
2805 // values computed in phase 2.  This results in:
2806 //
2807 //     7 Parm #memory
2808 //    10  ConI  "12"
2809 //    19  CheckCastPP   "Foo"
2810 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2811 //    29  CheckCastPP   "Foo"  iid=24
2812 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2813 //
2814 //    40  StoreP  25  7   20   ... alias_index=4
2815 //    50  StoreP  35  7   30   ... alias_index=6
2816 //    60  StoreP  45  40  20   ... alias_index=4
2817 //    70  LoadP    _  50  30   ... alias_index=6
2818 //    80  Phi     75  40  60   Memory alias_index=4
2819 //   120  Phi     75  50  50   Memory alias_index=6
2820 //    90  LoadP    _ 120  30   ... alias_index=6
2821 //   100  LoadP    _  80  20   ... alias_index=4
2822 //
2823 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {
2824   GrowableArray<Node *>  memnode_worklist;
2825   GrowableArray<PhiNode *>  orig_phis;
2826   PhaseIterGVN  *igvn = _igvn;
2827   uint new_index_start = (uint) _compile->num_alias_types();
2828   Arena* arena = Thread::current()->resource_area();
2829   VectorSet visited(arena);
2830   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2831   uint unique_old = _compile->unique();
2832 
2833   //  Phase 1:  Process possible allocations from alloc_worklist.
2834   //  Create instance types for the CheckCastPP for allocations where possible.
2835   //
2836   // (Note: don't forget to change the order of the second AddP node on
2837   //  the alloc_worklist if the order of the worklist processing is changed,
2838   //  see the comment in find_second_addp().)
2839   //
2840   while (alloc_worklist.length() != 0) {
2841     Node *n = alloc_worklist.pop();
2842     uint ni = n->_idx;
2843     if (n->is_Call()) {
2844       CallNode *alloc = n->as_Call();
2845       // copy escape information to call node
2846       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2847       PointsToNode::EscapeState es = ptn->escape_state();
2848       // We have an allocation or call which returns a Java object,
2849       // see if it is unescaped.
2850       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2851         continue;
2852       // Find CheckCastPP for the allocate or for the return value of a call
2853       n = alloc->result_cast();
2854       if (n == NULL) {            // No uses except Initialize node
2855         if (alloc->is_Allocate()) {
2856           // Set the scalar_replaceable flag for allocation
2857           // so it could be eliminated if it has no uses.
2858           alloc->as_Allocate()->_is_scalar_replaceable = true;
2859         }
2860         if (alloc->is_CallStaticJava()) {
2861           // Set the scalar_replaceable flag for boxing method
2862           // so it could be eliminated if it has no uses.
2863           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2864         }
2865         continue;
2866       }
2867       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2868         assert(!alloc->is_Allocate(), "allocation should have unique type");
2869         continue;
2870       }
2871 
2872       // The inline code for Object.clone() casts the allocation result to
2873       // java.lang.Object and then to the actual type of the allocated
2874       // object. Detect this case and use the second cast.
2875       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2876       // the allocation result is cast to java.lang.Object and then
2877       // to the actual Array type.
2878       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2879           && (alloc->is_AllocateArray() ||
2880               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2881         Node *cast2 = NULL;
2882         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2883           Node *use = n->fast_out(i);
2884           if (use->is_CheckCastPP()) {
2885             cast2 = use;
2886             break;
2887           }
2888         }
2889         if (cast2 != NULL) {
2890           n = cast2;
2891         } else {
2892           // Non-scalar replaceable if the allocation type is unknown statically
2893           // (reflection allocation), the object can't be restored during
2894           // deoptimization without precise type.
2895           continue;
2896         }
2897       }
2898 
2899       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2900       if (t == NULL)
2901         continue;  // not a TypeOopPtr
2902       if (!t->klass_is_exact())
2903         continue; // not an unique type
2904 
2905       if (alloc->is_Allocate()) {
2906         // Set the scalar_replaceable flag for allocation
2907         // so it could be eliminated.
2908         alloc->as_Allocate()->_is_scalar_replaceable = true;
2909       }
2910       if (alloc->is_CallStaticJava()) {
2911         // Set the scalar_replaceable flag for boxing method
2912         // so it could be eliminated.
2913         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2914       }
2915       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2916       // in order for an object to be scalar-replaceable, it must be:
2917       //   - a direct allocation (not a call returning an object)
2918       //   - non-escaping
2919       //   - eligible to be a unique type
2920       //   - not determined to be ineligible by escape analysis
2921       set_map(alloc, n);
2922       set_map(n, alloc);
2923       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2924       igvn->hash_delete(n);
2925       igvn->set_type(n,  tinst);
2926       n->raise_bottom_type(tinst);
2927       igvn->hash_insert(n);
2928       record_for_optimizer(n);
2929       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2930 
2931         // First, put on the worklist all Field edges from Connection Graph
2932         // which is more accurate then putting immediate users from Ideal Graph.
2933         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2934           PointsToNode* tgt = e.get();
2935           Node* use = tgt->ideal_node();
2936           assert(tgt->is_Field() && use->is_AddP(),
2937                  "only AddP nodes are Field edges in CG");
2938           if (use->outcnt() > 0) { // Don't process dead nodes
2939             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
2940             if (addp2 != NULL) {
2941               assert(alloc->is_AllocateArray(),"array allocation was expected");
2942               alloc_worklist.append_if_missing(addp2);
2943             }
2944             alloc_worklist.append_if_missing(use);
2945           }
2946         }
2947 
2948         // An allocation may have an Initialize which has raw stores. Scan
2949         // the users of the raw allocation result and push AddP users
2950         // on alloc_worklist.
2951         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
2952         assert (raw_result != NULL, "must have an allocation result");
2953         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
2954           Node *use = raw_result->fast_out(i);
2955           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
2956             Node* addp2 = find_second_addp(use, raw_result);
2957             if (addp2 != NULL) {
2958               assert(alloc->is_AllocateArray(),"array allocation was expected");
2959               alloc_worklist.append_if_missing(addp2);
2960             }
2961             alloc_worklist.append_if_missing(use);
2962           } else if (use->is_MemBar()) {
2963             memnode_worklist.append_if_missing(use);
2964           }
2965         }
2966       }
2967     } else if (n->is_AddP()) {
2968       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
2969       if (jobj == NULL || jobj == phantom_obj) {
2970 #ifdef ASSERT
2971         ptnode_adr(get_addp_base(n)->_idx)->dump();
2972         ptnode_adr(n->_idx)->dump();
2973         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
2974 #endif
2975         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
2976         return;
2977       }
2978       Node *base = get_map(jobj->idx());  // CheckCastPP node
2979       if (!split_AddP(n, base)) continue; // wrong type from dead path
2980     } else if (n->is_Phi() ||
2981                n->is_CheckCastPP() ||
2982                n->is_EncodeP() ||
2983                n->is_DecodeN() ||
2984                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
2985       if (visited.test_set(n->_idx)) {
2986         assert(n->is_Phi(), "loops only through Phi's");
2987         continue;  // already processed
2988       }
2989       JavaObjectNode* jobj = unique_java_object(n);
2990       if (jobj == NULL || jobj == phantom_obj) {
2991 #ifdef ASSERT
2992         ptnode_adr(n->_idx)->dump();
2993         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
2994 #endif
2995         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
2996         return;
2997       } else {
2998         Node *val = get_map(jobj->idx());   // CheckCastPP node
2999         TypeNode *tn = n->as_Type();
3000         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3001         assert(tinst != NULL && tinst->is_known_instance() &&
3002                tinst->instance_id() == jobj->idx() , "instance type expected.");
3003 
3004         const Type *tn_type = igvn->type(tn);
3005         const TypeOopPtr *tn_t;
3006         if (tn_type->isa_narrowoop()) {
3007           tn_t = tn_type->make_ptr()->isa_oopptr();
3008         } else {
3009           tn_t = tn_type->isa_oopptr();
3010         }
3011         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3012           if (tn_type->isa_narrowoop()) {
3013             tn_type = tinst->make_narrowoop();
3014           } else {
3015             tn_type = tinst;
3016           }
3017           igvn->hash_delete(tn);
3018           igvn->set_type(tn, tn_type);
3019           tn->set_type(tn_type);
3020           igvn->hash_insert(tn);
3021           record_for_optimizer(n);
3022         } else {
3023           assert(tn_type == TypePtr::NULL_PTR ||
3024                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3025                  "unexpected type");
3026           continue; // Skip dead path with different type
3027         }
3028       }
3029     } else {
3030       debug_only(n->dump();)
3031       assert(false, "EA: unexpected node");
3032       continue;
3033     }
3034     // push allocation's users on appropriate worklist
3035     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3036       Node *use = n->fast_out(i);
3037       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3038         // Load/store to instance's field
3039         memnode_worklist.append_if_missing(use);
3040       } else if (use->is_MemBar()) {
3041         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3042           memnode_worklist.append_if_missing(use);
3043         }
3044       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3045         Node* addp2 = find_second_addp(use, n);
3046         if (addp2 != NULL) {
3047           alloc_worklist.append_if_missing(addp2);
3048         }
3049         alloc_worklist.append_if_missing(use);
3050       } else if (use->is_Phi() ||
3051                  use->is_CheckCastPP() ||
3052                  use->is_EncodeNarrowPtr() ||
3053                  use->is_DecodeNarrowPtr() ||
3054                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3055         alloc_worklist.append_if_missing(use);
3056 #ifdef ASSERT
3057       } else if (use->is_Mem()) {
3058         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3059       } else if (use->is_MergeMem()) {
3060         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3061       } else if (use->is_SafePoint()) {
3062         // Look for MergeMem nodes for calls which reference unique allocation
3063         // (through CheckCastPP nodes) even for debug info.
3064         Node* m = use->in(TypeFunc::Memory);
3065         if (m->is_MergeMem()) {
3066           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3067         }
3068       } else if (use->Opcode() == Op_EncodeISOArray) {
3069         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3070           // EncodeISOArray overwrites destination array
3071           memnode_worklist.append_if_missing(use);
3072         }
3073       } else {
3074         uint op = use->Opcode();
3075         if (!(op == Op_CmpP || op == Op_Conv2B ||
3076               op == Op_CastP2X || op == Op_StoreCM ||
3077               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
3078               op == Op_StrEquals || op == Op_StrIndexOf)) {
3079           n->dump();
3080           use->dump();
3081           assert(false, "EA: missing allocation reference path");
3082         }
3083 #endif
3084       }
3085     }
3086 
3087   }
3088   // New alias types were created in split_AddP().
3089   uint new_index_end = (uint) _compile->num_alias_types();
3090   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3091 
3092   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3093   //            compute new values for Memory inputs  (the Memory inputs are not
3094   //            actually updated until phase 4.)
3095   if (memnode_worklist.length() == 0)
3096     return;  // nothing to do
3097   while (memnode_worklist.length() != 0) {
3098     Node *n = memnode_worklist.pop();
3099     if (visited.test_set(n->_idx))
3100       continue;
3101     if (n->is_Phi() || n->is_ClearArray()) {
3102       // we don't need to do anything, but the users must be pushed
3103     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3104       // we don't need to do anything, but the users must be pushed
3105       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3106       if (n == NULL)
3107         continue;
3108     } else if (n->Opcode() == Op_EncodeISOArray) {
3109       // get the memory projection
3110       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3111         Node *use = n->fast_out(i);
3112         if (use->Opcode() == Op_SCMemProj) {
3113           n = use;
3114           break;
3115         }
3116       }
3117       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3118     } else {
3119       assert(n->is_Mem(), "memory node required.");
3120       Node *addr = n->in(MemNode::Address);
3121       const Type *addr_t = igvn->type(addr);
3122       if (addr_t == Type::TOP)
3123         continue;
3124       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3125       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3126       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3127       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3128       if (_compile->failing()) {
3129         return;
3130       }
3131       if (mem != n->in(MemNode::Memory)) {
3132         // We delay the memory edge update since we need old one in
3133         // MergeMem code below when instances memory slices are separated.
3134         set_map(n, mem);
3135       }
3136       if (n->is_Load()) {
3137         continue;  // don't push users
3138       } else if (n->is_LoadStore()) {
3139         // get the memory projection
3140         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3141           Node *use = n->fast_out(i);
3142           if (use->Opcode() == Op_SCMemProj) {
3143             n = use;
3144             break;
3145           }
3146         }
3147         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3148       }
3149     }
3150     // push user on appropriate worklist
3151     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3152       Node *use = n->fast_out(i);
3153       if (use->is_Phi() || use->is_ClearArray()) {
3154         memnode_worklist.append_if_missing(use);
3155       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3156         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3157           continue;
3158         memnode_worklist.append_if_missing(use);
3159       } else if (use->is_MemBar()) {
3160         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3161           memnode_worklist.append_if_missing(use);
3162         }
3163 #ifdef ASSERT
3164       } else if(use->is_Mem()) {
3165         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3166       } else if (use->is_MergeMem()) {
3167         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3168       } else if (use->Opcode() == Op_EncodeISOArray) {
3169         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3170           // EncodeISOArray overwrites destination array
3171           memnode_worklist.append_if_missing(use);
3172         }
3173       } else {
3174         uint op = use->Opcode();
3175         if (!(op == Op_StoreCM ||
3176               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3177                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3178               op == Op_AryEq || op == Op_StrComp ||
3179               op == Op_StrEquals || op == Op_StrIndexOf)) {
3180           n->dump();
3181           use->dump();
3182           assert(false, "EA: missing memory path");
3183         }
3184 #endif
3185       }
3186     }
3187   }
3188 
3189   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3190   //            Walk each memory slice moving the first node encountered of each
3191   //            instance type to the the input corresponding to its alias index.
3192   uint length = _mergemem_worklist.length();
3193   for( uint next = 0; next < length; ++next ) {
3194     MergeMemNode* nmm = _mergemem_worklist.at(next);
3195     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3196     // Note: we don't want to use MergeMemStream here because we only want to
3197     // scan inputs which exist at the start, not ones we add during processing.
3198     // Note 2: MergeMem may already contains instance memory slices added
3199     // during find_inst_mem() call when memory nodes were processed above.
3200     igvn->hash_delete(nmm);
3201     uint nslices = MIN2(nmm->req(), new_index_start);
3202     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3203       Node* mem = nmm->in(i);
3204       Node* cur = NULL;
3205       if (mem == NULL || mem->is_top())
3206         continue;
3207       // First, update mergemem by moving memory nodes to corresponding slices
3208       // if their type became more precise since this mergemem was created.
3209       while (mem->is_Mem()) {
3210         const Type *at = igvn->type(mem->in(MemNode::Address));
3211         if (at != Type::TOP) {
3212           assert (at->isa_ptr() != NULL, "pointer type required.");
3213           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3214           if (idx == i) {
3215             if (cur == NULL)
3216               cur = mem;
3217           } else {
3218             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3219               nmm->set_memory_at(idx, mem);
3220             }
3221           }
3222         }
3223         mem = mem->in(MemNode::Memory);
3224       }
3225       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3226       // Find any instance of the current type if we haven't encountered
3227       // already a memory slice of the instance along the memory chain.
3228       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3229         if((uint)_compile->get_general_index(ni) == i) {
3230           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3231           if (nmm->is_empty_memory(m)) {
3232             Node* result = find_inst_mem(mem, ni, orig_phis);
3233             if (_compile->failing()) {
3234               return;
3235             }
3236             nmm->set_memory_at(ni, result);
3237           }
3238         }
3239       }
3240     }
3241     // Find the rest of instances values
3242     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3243       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3244       Node* result = step_through_mergemem(nmm, ni, tinst);
3245       if (result == nmm->base_memory()) {
3246         // Didn't find instance memory, search through general slice recursively.
3247         result = nmm->memory_at(_compile->get_general_index(ni));
3248         result = find_inst_mem(result, ni, orig_phis);
3249         if (_compile->failing()) {
3250           return;
3251         }
3252         nmm->set_memory_at(ni, result);
3253       }
3254     }
3255     igvn->hash_insert(nmm);
3256     record_for_optimizer(nmm);
3257   }
3258 
3259   //  Phase 4:  Update the inputs of non-instance memory Phis and
3260   //            the Memory input of memnodes
3261   // First update the inputs of any non-instance Phi's from
3262   // which we split out an instance Phi.  Note we don't have
3263   // to recursively process Phi's encounted on the input memory
3264   // chains as is done in split_memory_phi() since they  will
3265   // also be processed here.
3266   for (int j = 0; j < orig_phis.length(); j++) {
3267     PhiNode *phi = orig_phis.at(j);
3268     int alias_idx = _compile->get_alias_index(phi->adr_type());
3269     igvn->hash_delete(phi);
3270     for (uint i = 1; i < phi->req(); i++) {
3271       Node *mem = phi->in(i);
3272       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3273       if (_compile->failing()) {
3274         return;
3275       }
3276       if (mem != new_mem) {
3277         phi->set_req(i, new_mem);
3278       }
3279     }
3280     igvn->hash_insert(phi);
3281     record_for_optimizer(phi);
3282   }
3283 
3284   // Update the memory inputs of MemNodes with the value we computed
3285   // in Phase 2 and move stores memory users to corresponding memory slices.
3286   // Disable memory split verification code until the fix for 6984348.
3287   // Currently it produces false negative results since it does not cover all cases.
3288 #if 0 // ifdef ASSERT
3289   visited.Reset();
3290   Node_Stack old_mems(arena, _compile->unique() >> 2);
3291 #endif
3292   for (uint i = 0; i < ideal_nodes.size(); i++) {
3293     Node*    n = ideal_nodes.at(i);
3294     Node* nmem = get_map(n->_idx);
3295     assert(nmem != NULL, "sanity");
3296     if (n->is_Mem()) {
3297 #if 0 // ifdef ASSERT
3298       Node* old_mem = n->in(MemNode::Memory);
3299       if (!visited.test_set(old_mem->_idx)) {
3300         old_mems.push(old_mem, old_mem->outcnt());
3301       }
3302 #endif
3303       assert(n->in(MemNode::Memory) != nmem, "sanity");
3304       if (!n->is_Load()) {
3305         // Move memory users of a store first.
3306         move_inst_mem(n, orig_phis);
3307       }
3308       // Now update memory input
3309       igvn->hash_delete(n);
3310       n->set_req(MemNode::Memory, nmem);
3311       igvn->hash_insert(n);
3312       record_for_optimizer(n);
3313     } else {
3314       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3315              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3316     }
3317   }
3318 #if 0 // ifdef ASSERT
3319   // Verify that memory was split correctly
3320   while (old_mems.is_nonempty()) {
3321     Node* old_mem = old_mems.node();
3322     uint  old_cnt = old_mems.index();
3323     old_mems.pop();
3324     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3325   }
3326 #endif
3327 }
3328 
3329 #ifndef PRODUCT
3330 static const char *node_type_names[] = {
3331   "UnknownType",
3332   "JavaObject",
3333   "LocalVar",
3334   "Field",
3335   "Arraycopy"
3336 };
3337 
3338 static const char *esc_names[] = {
3339   "UnknownEscape",
3340   "NoEscape",
3341   "ArgEscape",
3342   "GlobalEscape"
3343 };
3344 
3345 void PointsToNode::dump(bool print_state) const {
3346   NodeType nt = node_type();
3347   tty->print("%s ", node_type_names[(int) nt]);
3348   if (print_state) {
3349     EscapeState es = escape_state();
3350     EscapeState fields_es = fields_escape_state();
3351     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3352     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3353       tty->print("NSR ");
3354   }
3355   if (is_Field()) {
3356     FieldNode* f = (FieldNode*)this;
3357     if (f->is_oop())
3358       tty->print("oop ");
3359     if (f->offset() > 0)
3360       tty->print("+%d ", f->offset());
3361     tty->print("(");
3362     for (BaseIterator i(f); i.has_next(); i.next()) {
3363       PointsToNode* b = i.get();
3364       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3365     }
3366     tty->print(" )");
3367   }
3368   tty->print("[");
3369   for (EdgeIterator i(this); i.has_next(); i.next()) {
3370     PointsToNode* e = i.get();
3371     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3372   }
3373   tty->print(" [");
3374   for (UseIterator i(this); i.has_next(); i.next()) {
3375     PointsToNode* u = i.get();
3376     bool is_base = false;
3377     if (PointsToNode::is_base_use(u)) {
3378       is_base = true;
3379       u = PointsToNode::get_use_node(u)->as_Field();
3380     }
3381     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3382   }
3383   tty->print(" ]]  ");
3384   if (_node == NULL)
3385     tty->print_cr("<null>");
3386   else
3387     _node->dump();
3388 }
3389 
3390 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3391   bool first = true;
3392   int ptnodes_length = ptnodes_worklist.length();
3393   for (int i = 0; i < ptnodes_length; i++) {
3394     PointsToNode *ptn = ptnodes_worklist.at(i);
3395     if (ptn == NULL || !ptn->is_JavaObject())
3396       continue;
3397     PointsToNode::EscapeState es = ptn->escape_state();
3398     if ((es != PointsToNode::NoEscape) && !Verbose) {
3399       continue;
3400     }
3401     Node* n = ptn->ideal_node();
3402     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3403                              n->as_CallStaticJava()->is_boxing_method())) {
3404       if (first) {
3405         tty->cr();
3406         tty->print("======== Connection graph for ");
3407         _compile->method()->print_short_name();
3408         tty->cr();
3409         first = false;
3410       }
3411       ptn->dump();
3412       // Print all locals and fields which reference this allocation
3413       for (UseIterator j(ptn); j.has_next(); j.next()) {
3414         PointsToNode* use = j.get();
3415         if (use->is_LocalVar()) {
3416           use->dump(Verbose);
3417         } else if (Verbose) {
3418           use->dump();
3419         }
3420       }
3421       tty->cr();
3422     }
3423   }
3424 }
3425 #endif