1 /*
   2  * Copyright (c) 2005, 2012, 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 "libadt/vectset.hpp"
  28 #include "memory/allocation.hpp"
  29 #include "opto/c2compiler.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/compile.hpp"
  33 #include "opto/escape.hpp"
  34 #include "opto/phaseX.hpp"
  35 #include "opto/rootnode.hpp"
  36 
  37 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  38   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  39   _collecting(true),
  40   _verify(false),
  41   _compile(C),
  42   _igvn(igvn),
  43   _node_map(C->comp_arena()) {
  44 
  45   add_java_object(C->top(), PointsToNode::GlobalEscape);
  46   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  47 
  48   // Add ConP(#NULL) and ConN(#NULL) nodes.
  49   Node* oop_null = igvn->zerocon(T_OBJECT);
  50   assert(oop_null->_idx < nodes_size(), "should be created already");
  51   add_java_object(oop_null, PointsToNode::NoEscape);
  52   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  53 
  54   if (UseCompressedOops) {
  55     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  56     assert(noop_null->_idx < nodes_size(), "should be created already");
  57     map_ideal_node(noop_null, null_obj);
  58   }
  59   _pcmp_neq = NULL; // Should be initialized
  60   _pcmp_eq  = NULL;
  61 }
  62 
  63 // Connection Graph constuction functions.
  64 
  65 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
  66   PointsToNode* ptadr = _nodes.at(n->_idx);
  67   if (ptadr != NULL) {
  68     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
  69     return;
  70   }
  71   ptadr = new LocalVarNode(n, es);
  72   _nodes.at_put(n->_idx, ptadr);
  73 }
  74 
  75 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
  76   PointsToNode* ptadr = _nodes.at(n->_idx);
  77   if (ptadr != NULL) {
  78     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
  79     return;
  80   }
  81   ptadr = new JavaObjectNode(n, es);
  82   _nodes.at_put(n->_idx, ptadr);
  83 }
  84 
  85 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
  86   PointsToNode* ptadr = _nodes.at(n->_idx);
  87   if (ptadr != NULL) {
  88     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
  89     return;
  90   }
  91   bool is_oop = is_oop_field(n, offset);
  92   FieldNode* field = new FieldNode(n, es, offset, is_oop);
  93   _nodes.at_put(n->_idx, field);
  94 }
  95 
  96 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
  97                                     PointsToNode* src, PointsToNode* dst) {
  98   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
  99   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
 100   PointsToNode* ptadr = _nodes.at(n->_idx);
 101   if (ptadr != NULL) {
 102     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
 103     return;
 104   }
 105   ptadr = new ArraycopyNode(n, es);
 106   _nodes.at_put(n->_idx, ptadr);
 107   // Add edge from arraycopy node to source object.
 108   (void)add_edge(ptadr, src);
 109   src->set_arraycopy_src();
 110   // Add edge from destination object to arraycopy node.
 111   (void)add_edge(dst, ptadr);
 112   dst->set_arraycopy_dst();
 113 }
 114 
 115 bool ConnectionGraph::is_oop_field(Node* n, int offset) {
 116   const Type* adr_type = n->as_AddP()->bottom_type();
 117   BasicType bt = T_INT;
 118   if (offset == Type::OffsetBot) {
 119     // Check only oop fields.
 120     if (!adr_type->isa_aryptr() ||
 121         (adr_type->isa_aryptr()->klass() == NULL) ||
 122          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
 123       // OffsetBot is used to reference array's element. Ignore first AddP.
 124       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
 125         bt = T_OBJECT;
 126       }
 127     }
 128   } else if (offset != oopDesc::klass_offset_in_bytes()) {
 129     if (adr_type->isa_instptr()) {
 130       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
 131       if (field != NULL) {
 132         bt = field->layout_type();
 133       } else {
 134         // Ignore non field load (for example, klass load)
 135       }
 136     } else if (adr_type->isa_aryptr()) {
 137       if (offset == arrayOopDesc::length_offset_in_bytes()) {
 138         // Ignore array length load.
 139       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
 140         // Ignore first AddP.
 141       } else {
 142         const Type* elemtype = adr_type->isa_aryptr()->elem();
 143         bt = elemtype->array_element_basic_type();
 144       }
 145     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
 146       // Allocation initialization, ThreadLocal field access, unsafe access
 147       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 148         int opcode = n->fast_out(i)->Opcode();
 149         if (opcode == Op_StoreP || opcode == Op_LoadP ||
 150             opcode == Op_StoreN || opcode == Op_LoadN) {
 151           bt = T_OBJECT;
 152         }
 153       }
 154     }
 155   }
 156   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
 157 }
 158 
 159 // Add all references to JavaObject node by walking over all uses.
 160 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj,
 161                                             bool populate_worklist) {
 162   int new_edges = 0;
 163   if (populate_worklist) {
 164     // Populate _worklist by uses of jobj's uses.
 165     uint count = jobj->use_count();
 166     for (uint i = 0; i < count; i++) {
 167       PointsToNode* use = jobj->use(i);
 168       if (use->is_Arraycopy())
 169         continue;
 170 
 171       add_uses_to_worklist(use);
 172       if (use->is_Field() && use->as_Field()->is_oop()) {
 173         // Put on worklist all field's uses (loads) and
 174         // related field nodes (same base and offset).
 175         add_field_uses_to_worklist(use->as_Field());
 176       }
 177     }
 178   }
 179 
 180   while(_worklist.length() > 0) {
 181     PointsToNode* use = _worklist.pop();
 182 
 183     if (PointsToNode::is_base_use(use)) {
 184       // Add reference from jobj to field and from field to jobj (field's base).
 185       use = PointsToNode::get_use_node(use)->as_Field();
 186       if (add_base(use->as_Field(), jobj))
 187         new_edges++;
 188       continue;
 189     }
 190     assert(!use->is_JavaObject(), "sanity");
 191 
 192     if (use->is_Arraycopy()) {
 193       if (jobj == null_obj) // NULL object does not have field edges
 194         continue;
 195 
 196       // Added edge from Arraycopy node to arraycopy's source java object
 197       if (add_edge(use, jobj)) {
 198         jobj->set_arraycopy_src();
 199         new_edges++;
 200       }
 201       // and stop here.
 202       continue;
 203     }
 204 
 205     if (!add_edge(use, jobj))
 206       continue; // No new edge added, there was such edge already.
 207 
 208     new_edges++;
 209 
 210     if (use->is_LocalVar()) {
 211       add_uses_to_worklist(use);
 212       if (use->arraycopy_dst()) {
 213         uint ecnt = use->edge_count();
 214         for (uint j = 0; j < ecnt; j++) {
 215           PointsToNode* e = use->edge(j);
 216           if (e->is_Arraycopy()) {
 217             if (jobj == null_obj) // NULL object does not have field edges
 218               continue;
 219             // Add edge from arraycopy's destination java object to Arraycopy node.
 220             if (add_edge(jobj, e)) {
 221               new_edges++;
 222               jobj->set_arraycopy_dst();
 223             }
 224           }
 225         }
 226       }
 227     } else {
 228       // Added new edge to stored in field values.
 229       // Put on worklist all field's uses (loads) and
 230       // related field nodes (same base and offset).
 231       add_field_uses_to_worklist(use->as_Field());
 232     }
 233   }
 234   return new_edges;
 235 }
 236 
 237 // Put on worklist all related field nodes.
 238 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
 239   assert(field->is_oop(), "sanity");
 240   int offset = field->offset();
 241   add_uses_to_worklist(field);
 242 
 243   // Loop over all bases of this field and push on worklist Field nodes
 244   // with the same offset and base (since they may reference the same field).
 245   uint bcnt = field->base_count();
 246   for (uint i = 0; i < bcnt; i++) {
 247     PointsToNode* base = field->base(i);
 248     add_fields_to_worklist(field, base);
 249 
 250     // Check if the base was source object of arraycopy and go over arraycopy's
 251     // destination objects since values stored to a field of source object are
 252     // accessable by uses (loads) of fields of destination objects.
 253     if (base->arraycopy_src()) {
 254       uint ucnt = base->use_count();
 255       for (uint j = 0; j < ucnt; j++) {
 256         PointsToNode* arycp = base->use(j);
 257         if (arycp->is_Arraycopy()) {
 258           uint acnt = arycp->use_count();
 259           for (uint k = 0; k < acnt; k++) {
 260             PointsToNode* abase = arycp->use(k);
 261             if (abase->arraycopy_dst() && abase != base) {
 262               // Look for the same arracopy reference.
 263               add_fields_to_worklist(field, abase);
 264             }
 265           }
 266         }
 267       }
 268     }
 269   }
 270 }
 271 
 272 // Put on worklist all related field nodes.
 273 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
 274   int offset = field->offset();
 275   if (base->is_LocalVar()) {
 276     uint fcnt = base->use_count();
 277     for (uint j = 0; j < fcnt; j++) {
 278       PointsToNode* f = base->use(j);
 279       if (PointsToNode::is_base_use(f)) { // Field
 280         f = PointsToNode::get_use_node(f);
 281         if (f == field || !f->as_Field()->is_oop())
 282           continue;
 283         int offs = f->as_Field()->offset();
 284         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
 285           add_to_worklist(f);
 286         }
 287       }
 288     }
 289   } else {
 290     assert(base->is_JavaObject(), "sanity");
 291     if (// Skip phantom_object since it is only used to indicate that
 292         // this field's content globally escapes.
 293         (base != phantom_obj) &&
 294         // NULL object node does not have fields.
 295         (base != null_obj)) {
 296       uint fcnt = base->edge_count();
 297       for (uint j = 0; j < fcnt; j++) {
 298         PointsToNode* f = base->edge(j);
 299         // Skip arraycopy edge since store to destination object field
 300         // does not update value in source object field.
 301         if (f->is_Arraycopy()) {
 302           assert(base->arraycopy_dst(), "sanity");
 303           continue;
 304         }
 305         if (f == field || !f->as_Field()->is_oop())
 306           continue;
 307         int offs = f->as_Field()->offset();
 308         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
 309           add_to_worklist(f);
 310         }
 311       }
 312     }
 313   }
 314 }
 315 
 316 // Returns unique pointed java object or NULL.
 317 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
 318   assert(!_collecting, "should not call when contructed graph");
 319 
 320   // If the node was created after the escape computation we can't answer.
 321   uint idx = n->_idx;
 322   if (idx >= nodes_size())
 323     return NULL;
 324 
 325   PointsToNode* ptn = ptnode_adr(idx);
 326   if (ptn->is_JavaObject()) {
 327     return ptn->as_JavaObject();
 328   }
 329 
 330   assert(ptn->is_LocalVar(), "sanity");
 331   // Check all java objects it points to.
 332   uint count = ptn->edge_count();
 333   JavaObjectNode* jobj = NULL;
 334   for (uint i = 0; i < count; i++) {
 335     PointsToNode* e = ptn->edge(i);
 336     if (e->is_JavaObject()) {
 337       if (jobj == NULL) {
 338         jobj = e->as_JavaObject();
 339       } else if (jobj != e) {
 340         return NULL;
 341       }
 342     }
 343   }
 344   return jobj;
 345 }
 346 
 347 // Return true if nodes points only to non-escaped allocations.
 348 bool PointsToNode::not_escaped_allocation() {
 349   if (is_JavaObject()) {
 350     Node* n = ideal_node();
 351     if (n->is_Allocate() || n->is_CallStaticJava()) {
 352       return (escape_state() == PointsToNode::NoEscape);
 353     } else {
 354       return false;
 355     }
 356   }
 357   assert(is_LocalVar(), "sanity");
 358   // Check all java objects it points to.
 359   uint count = edge_count();
 360   for (uint i = 0; i < count; i++) {
 361     PointsToNode* e = edge(i);
 362     if (e->is_JavaObject()) {
 363       Node* n = e->ideal_node();
 364       if ((e->escape_state() != PointsToNode::NoEscape) ||
 365           !(n->is_Allocate() || n->is_CallStaticJava())) {
 366         return false;
 367       }
 368     }
 369   }
 370   return true;
 371 }
 372 
 373 // Return true if we know the node does not escape globally.
 374 bool ConnectionGraph::not_global_escape(Node *n) {
 375   assert(!_collecting, "should not call during graph construction");
 376 
 377   // If the node was created after the escape computation we can't answer.
 378   uint idx = n->_idx;
 379   if (idx >= nodes_size())
 380     return false;
 381 
 382   PointsToNode* ptn = ptnode_adr(idx);
 383   PointsToNode::EscapeState es = ptn->escape_state();
 384 
 385   // If we have already computed a value, return it.
 386   if (es >= PointsToNode::GlobalEscape)
 387     return false;
 388 
 389   if (ptn->is_JavaObject()) {
 390     return true; // (es < PointsToNode::GlobalEscape);
 391   }
 392 
 393   assert(ptn->is_LocalVar(), "sanity");
 394   // Check all java objects it points to.
 395   uint count = ptn->edge_count();
 396   for (uint i = 0; i < count; i++) {
 397     if (ptn->edge(i)->escape_state() >= PointsToNode::GlobalEscape)
 398       return false;
 399   }
 400   return true;
 401 }
 402 
 403 
 404 // Helper functions
 405 
 406 // Return true if this node points to specified node or nodes it points to.
 407 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
 408   if (this->is_JavaObject())
 409     return (this == ptn);
 410 
 411   assert(this->is_LocalVar(), "sanity");
 412 
 413   uint count = this->edge_count();
 414   for (uint i = 0; i < count; i++) {
 415     PointsToNode* e = this->edge(i);
 416     if (e == ptn)
 417       return true;
 418   }
 419   return false;
 420 }
 421 
 422 // Return true if one node points to an other.
 423 bool PointsToNode::meet(PointsToNode* ptn) {
 424   if (this == ptn)
 425     return true;
 426 
 427   if (ptn->is_JavaObject())
 428     return this->points_to(ptn->as_JavaObject());
 429 
 430   if (this->is_JavaObject())
 431     return ptn->points_to(this->as_JavaObject());
 432 
 433   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
 434 
 435   uint this_count = this->edge_count();
 436   uint  ptn_count =  ptn->edge_count();
 437   for (uint i = 0; i < this_count; i++) {
 438     PointsToNode* this_e = this->edge(i);
 439     for (uint j = 0; j < ptn_count; j++) {
 440       PointsToNode* ptn_e = ptn->edge(j);
 441       if (this_e == ptn_e)
 442         return true;
 443     }
 444   }
 445   return false;
 446 }
 447 
 448 #ifdef ASSERT
 449 // Return true if bases points to this java object.
 450 bool FieldNode::has_base(JavaObjectNode* jobj) const {
 451   uint count = this->base_count();
 452   for (uint i = 0; i < count; i++) {
 453     PointsToNode* b = this->base(i);
 454     if (b == jobj)
 455       return true;
 456   }
 457   return false;
 458 }
 459 #endif
 460 
 461 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
 462   const Type *adr_type = phase->type(adr);
 463   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
 464       adr->in(AddPNode::Address)->is_Proj() &&
 465       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
 466     // We are computing a raw address for a store captured by an Initialize
 467     // compute an appropriate address type. AddP cases #3 and #5 (see below).
 468     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 469     assert(offs != Type::OffsetBot ||
 470            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
 471            "offset must be a constant or it is initialization of array");
 472     return offs;
 473   }
 474   const TypePtr *t_ptr = adr_type->isa_ptr();
 475   assert(t_ptr != NULL, "must be a pointer type");
 476   return t_ptr->offset();
 477 }
 478 
 479 Node* ConnectionGraph::get_addp_base(Node *addp) {
 480   assert(addp->is_AddP(), "must be AddP");
 481   //
 482   // AddP cases for Base and Address inputs:
 483   // case #1. Direct object's field reference:
 484   //     Allocate
 485   //       |
 486   //     Proj #5 ( oop result )
 487   //       |
 488   //     CheckCastPP (cast to instance type)
 489   //      | |
 490   //     AddP  ( base == address )
 491   //
 492   // case #2. Indirect object's field reference:
 493   //      Phi
 494   //       |
 495   //     CastPP (cast to instance type)
 496   //      | |
 497   //     AddP  ( base == address )
 498   //
 499   // case #3. Raw object's field reference for Initialize node:
 500   //      Allocate
 501   //        |
 502   //      Proj #5 ( oop result )
 503   //  top   |
 504   //     \  |
 505   //     AddP  ( base == top )
 506   //
 507   // case #4. Array's element reference:
 508   //   {CheckCastPP | CastPP}
 509   //     |  | |
 510   //     |  AddP ( array's element offset )
 511   //     |  |
 512   //     AddP ( array's offset )
 513   //
 514   // case #5. Raw object's field reference for arraycopy stub call:
 515   //          The inline_native_clone() case when the arraycopy stub is called
 516   //          after the allocation before Initialize and CheckCastPP nodes.
 517   //      Allocate
 518   //        |
 519   //      Proj #5 ( oop result )
 520   //       | |
 521   //       AddP  ( base == address )
 522   //
 523   // case #6. Constant Pool, ThreadLocal, CastX2P or
 524   //          Raw object's field reference:
 525   //      {ConP, ThreadLocal, CastX2P, raw Load}
 526   //  top   |
 527   //     \  |
 528   //     AddP  ( base == top )
 529   //
 530   // case #7. Klass's field reference.
 531   //      LoadKlass
 532   //       | |
 533   //       AddP  ( base == address )
 534   //
 535   // case #8. narrow Klass's field reference.
 536   //      LoadNKlass
 537   //       |
 538   //      DecodeN
 539   //       | |
 540   //       AddP  ( base == address )
 541   //
 542   Node *base = addp->in(AddPNode::Base);
 543   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
 544     base = addp->in(AddPNode::Address);
 545     while (base->is_AddP()) {
 546       // Case #6 (unsafe access) may have several chained AddP nodes.
 547       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
 548       base = base->in(AddPNode::Address);
 549     }
 550     Node* uncast_base = base->uncast();
 551     int opcode = uncast_base->Opcode();
 552     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
 553            opcode == Op_CastX2P || uncast_base->is_DecodeN() ||
 554            (uncast_base->is_Mem() && uncast_base->bottom_type() == TypeRawPtr::NOTNULL) ||
 555            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
 556   }
 557   return base;
 558 }
 559 
 560 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
 561   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
 562 
 563   Node* addp2 = addp->raw_out(0);
 564   if (addp->outcnt() == 1 && addp2->is_AddP() &&
 565       addp2->in(AddPNode::Base) == n &&
 566       addp2->in(AddPNode::Address) == addp) {
 567 
 568     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
 569     //
 570     // Find array's offset to push it on worklist first and
 571     // as result process an array's element offset first (pushed second)
 572     // to avoid CastPP for the array's offset.
 573     // Otherwise the inserted CastPP (LocalVar) will point to what
 574     // the AddP (Field) points to. Which would be wrong since
 575     // the algorithm expects the CastPP has the same point as
 576     // as AddP's base CheckCastPP (LocalVar).
 577     //
 578     //    ArrayAllocation
 579     //     |
 580     //    CheckCastPP
 581     //     |
 582     //    memProj (from ArrayAllocation CheckCastPP)
 583     //     |  ||
 584     //     |  ||   Int (element index)
 585     //     |  ||    |   ConI (log(element size))
 586     //     |  ||    |   /
 587     //     |  ||   LShift
 588     //     |  ||  /
 589     //     |  AddP (array's element offset)
 590     //     |  |
 591     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
 592     //     | / /
 593     //     AddP (array's offset)
 594     //      |
 595     //     Load/Store (memory operation on array's element)
 596     //
 597     return addp2;
 598   }
 599   return NULL;
 600 }
 601 
 602 //
 603 // Adjust the type and inputs of an AddP which computes the
 604 // address of a field of an instance
 605 //
 606 bool ConnectionGraph::split_AddP(Node *addp, Node *base,  PhaseGVN  *igvn) {
 607   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
 608   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
 609   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
 610   if (t == NULL) {
 611     // We are computing a raw address for a store captured by an Initialize
 612     // compute an appropriate address type (cases #3 and #5).
 613     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
 614     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
 615     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
 616     assert(offs != Type::OffsetBot, "offset must be a constant");
 617     t = base_t->add_offset(offs)->is_oopptr();
 618   }
 619   int inst_id =  base_t->instance_id();
 620   assert(!t->is_known_instance() || t->instance_id() == inst_id,
 621                              "old type must be non-instance or match new type");
 622 
 623   // The type 't' could be subclass of 'base_t'.
 624   // As result t->offset() could be large then base_t's size and it will
 625   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
 626   // constructor verifies correctness of the offset.
 627   //
 628   // It could happened on subclass's branch (from the type profiling
 629   // inlining) which was not eliminated during parsing since the exactness
 630   // of the allocation type was not propagated to the subclass type check.
 631   //
 632   // Or the type 't' could be not related to 'base_t' at all.
 633   // It could happened when CHA type is different from MDO type on a dead path
 634   // (for example, from instanceof check) which is not collapsed during parsing.
 635   //
 636   // Do nothing for such AddP node and don't process its users since
 637   // this code branch will go away.
 638   //
 639   if (!t->is_known_instance() &&
 640       !base_t->klass()->is_subtype_of(t->klass())) {
 641      return false; // bail out
 642   }
 643 
 644   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
 645   // Do NOT remove the next line: ensure a new alias index is allocated
 646   // for the instance type. Note: C++ will not remove it since the call
 647   // has side effect.
 648   int alias_idx = _compile->get_alias_index(tinst);
 649   igvn->set_type(addp, tinst);
 650   // record the allocation in the node map
 651   set_map(addp, get_map(base->_idx));
 652 
 653   // Set addp's Base and Address to 'base'.
 654   Node *abase = addp->in(AddPNode::Base);
 655   Node *adr   = addp->in(AddPNode::Address);
 656   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
 657       adr->in(0)->_idx == (uint)inst_id) {
 658     // Skip AddP cases #3 and #5.
 659   } else {
 660     assert(!abase->is_top(), "sanity"); // AddP case #3
 661     if (abase != base) {
 662       igvn->hash_delete(addp);
 663       addp->set_req(AddPNode::Base, base);
 664       if (abase == adr) {
 665         addp->set_req(AddPNode::Address, base);
 666       } else {
 667         // AddP case #4 (adr is array's element offset AddP node)
 668 #ifdef ASSERT
 669         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
 670         assert(adr->is_AddP() && atype != NULL &&
 671                atype->instance_id() == inst_id, "array's element offset should be processed first");
 672 #endif
 673       }
 674       igvn->hash_insert(addp);
 675     }
 676   }
 677   // Put on IGVN worklist since at least addp's type was changed above.
 678   record_for_optimizer(addp);
 679   return true;
 680 }
 681 
 682 //
 683 // Create a new version of orig_phi if necessary. Returns either the newly
 684 // created phi or an existing phi.  Sets create_new to indicate whether a new
 685 // phi was created.  Cache the last newly created phi in the node map.
 686 //
 687 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn, bool &new_created) {
 688   Compile *C = _compile;
 689   new_created = false;
 690   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
 691   // nothing to do if orig_phi is bottom memory or matches alias_idx
 692   if (phi_alias_idx == alias_idx) {
 693     return orig_phi;
 694   }
 695   // Have we recently created a Phi for this alias index?
 696   PhiNode *result = get_map_phi(orig_phi->_idx);
 697   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
 698     return result;
 699   }
 700   // Previous check may fail when the same wide memory Phi was split into Phis
 701   // for different memory slices. Search all Phis for this region.
 702   if (result != NULL) {
 703     Node* region = orig_phi->in(0);
 704     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
 705       Node* phi = region->fast_out(i);
 706       if (phi->is_Phi() &&
 707           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
 708         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
 709         return phi->as_Phi();
 710       }
 711     }
 712   }
 713   if ((int)C->unique() + 2*NodeLimitFudgeFactor > MaxNodeLimit) {
 714     if (C->do_escape_analysis() == true && !C->failing()) {
 715       // Retry compilation without escape analysis.
 716       // If this is the first failure, the sentinel string will "stick"
 717       // to the Compile object, and the C2Compiler will see it and retry.
 718       C->record_failure(C2Compiler::retry_no_escape_analysis());
 719     }
 720     return NULL;
 721   }
 722   orig_phi_worklist.append_if_missing(orig_phi);
 723   const TypePtr *atype = C->get_adr_type(alias_idx);
 724   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
 725   C->copy_node_notes_to(result, orig_phi);
 726   igvn->set_type(result, result->bottom_type());
 727   record_for_optimizer(result);
 728 
 729   set_map(orig_phi, result);
 730 
 731   new_created = true;
 732   return result;
 733 }
 734 
 735 //
 736 // Return a new version of Memory Phi "orig_phi" with the inputs having the
 737 // specified alias index.
 738 //
 739 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn) {
 740 
 741   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
 742   Compile *C = _compile;
 743   bool new_phi_created;
 744   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, igvn, new_phi_created);
 745   if (!new_phi_created) {
 746     return result;
 747   }
 748 
 749   GrowableArray<PhiNode *>  phi_list;
 750   GrowableArray<uint>  cur_input;
 751 
 752   PhiNode *phi = orig_phi;
 753   uint idx = 1;
 754   bool finished = false;
 755   while(!finished) {
 756     while (idx < phi->req()) {
 757       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, igvn);
 758       if (mem != NULL && mem->is_Phi()) {
 759         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, igvn, new_phi_created);
 760         if (new_phi_created) {
 761           // found an phi for which we created a new split, push current one on worklist and begin
 762           // processing new one
 763           phi_list.push(phi);
 764           cur_input.push(idx);
 765           phi = mem->as_Phi();
 766           result = newphi;
 767           idx = 1;
 768           continue;
 769         } else {
 770           mem = newphi;
 771         }
 772       }
 773       if (C->failing()) {
 774         return NULL;
 775       }
 776       result->set_req(idx++, mem);
 777     }
 778 #ifdef ASSERT
 779     // verify that the new Phi has an input for each input of the original
 780     assert( phi->req() == result->req(), "must have same number of inputs.");
 781     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
 782 #endif
 783     // Check if all new phi's inputs have specified alias index.
 784     // Otherwise use old phi.
 785     for (uint i = 1; i < phi->req(); i++) {
 786       Node* in = result->in(i);
 787       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
 788     }
 789     // we have finished processing a Phi, see if there are any more to do
 790     finished = (phi_list.length() == 0 );
 791     if (!finished) {
 792       phi = phi_list.pop();
 793       idx = cur_input.pop();
 794       PhiNode *prev_result = get_map_phi(phi->_idx);
 795       prev_result->set_req(idx++, result);
 796       result = prev_result;
 797     }
 798   }
 799   return result;
 800 }
 801 
 802 
 803 //
 804 // The next methods are derived from methods in MemNode.
 805 //
 806 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
 807   Node *mem = mmem;
 808   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
 809   // means an array I have not precisely typed yet.  Do not do any
 810   // alias stuff with it any time soon.
 811   if (toop->base() != Type::AnyPtr &&
 812       !(toop->klass() != NULL &&
 813         toop->klass()->is_java_lang_Object() &&
 814         toop->offset() == Type::OffsetBot)) {
 815     mem = mmem->memory_at(alias_idx);
 816     // Update input if it is progress over what we have now
 817   }
 818   return mem;
 819 }
 820 
 821 //
 822 // Move memory users to their memory slices.
 823 //
 824 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis, PhaseGVN *igvn) {
 825   Compile* C = _compile;
 826 
 827   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
 828   assert(tp != NULL, "ptr type");
 829   int alias_idx = C->get_alias_index(tp);
 830   int general_idx = C->get_general_index(alias_idx);
 831 
 832   // Move users first
 833   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 834     Node* use = n->fast_out(i);
 835     if (use->is_MergeMem()) {
 836       MergeMemNode* mmem = use->as_MergeMem();
 837       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
 838       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
 839         continue; // Nothing to do
 840       }
 841       // Replace previous general reference to mem node.
 842       uint orig_uniq = C->unique();
 843       Node* m = find_inst_mem(n, general_idx, orig_phis, igvn);
 844       assert(orig_uniq == C->unique(), "no new nodes");
 845       mmem->set_memory_at(general_idx, m);
 846       --imax;
 847       --i;
 848     } else if (use->is_MemBar()) {
 849       assert(!use->is_Initialize(), "initializing stores should not be moved");
 850       if (use->req() > MemBarNode::Precedent &&
 851           use->in(MemBarNode::Precedent) == n) {
 852         // Don't move related membars.
 853         record_for_optimizer(use);
 854         continue;
 855       }
 856       tp = use->as_MemBar()->adr_type()->isa_ptr();
 857       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
 858           alias_idx == general_idx) {
 859         continue; // Nothing to do
 860       }
 861       // Move to general memory slice.
 862       uint orig_uniq = C->unique();
 863       Node* m = find_inst_mem(n, general_idx, orig_phis, igvn);
 864       assert(orig_uniq == C->unique(), "no new nodes");
 865       igvn->hash_delete(use);
 866       imax -= use->replace_edge(n, m);
 867       igvn->hash_insert(use);
 868       record_for_optimizer(use);
 869       --i;
 870 #ifdef ASSERT
 871     } else if (use->is_Mem()) {
 872       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
 873         // Don't move related cardmark.
 874         continue;
 875       }
 876       // Memory nodes should have new memory input.
 877       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
 878       assert(tp != NULL, "ptr type");
 879       int idx = C->get_alias_index(tp);
 880       assert(get_map(use->_idx) != NULL || idx == alias_idx,
 881              "Following memory nodes should have new memory input or be on the same memory slice");
 882     } else if (use->is_Phi()) {
 883       // Phi nodes should be split and moved already.
 884       tp = use->as_Phi()->adr_type()->isa_ptr();
 885       assert(tp != NULL, "ptr type");
 886       int idx = C->get_alias_index(tp);
 887       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
 888     } else {
 889       use->dump();
 890       assert(false, "should not be here");
 891 #endif
 892     }
 893   }
 894 }
 895 
 896 //
 897 // Search memory chain of "mem" to find a MemNode whose address
 898 // is the specified alias index.
 899 //
 900 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, PhaseGVN *phase) {
 901   if (orig_mem == NULL)
 902     return orig_mem;
 903   Compile* C = phase->C;
 904   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
 905   bool is_instance = (toop != NULL) && toop->is_known_instance();
 906   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
 907   Node *prev = NULL;
 908   Node *result = orig_mem;
 909   while (prev != result) {
 910     prev = result;
 911     if (result == start_mem)
 912       break;  // hit one of our sentinels
 913     if (result->is_Mem()) {
 914       const Type *at = phase->type(result->in(MemNode::Address));
 915       if (at == Type::TOP)
 916         break; // Dead
 917       assert (at->isa_ptr() != NULL, "pointer type required.");
 918       int idx = C->get_alias_index(at->is_ptr());
 919       if (idx == alias_idx)
 920         break; // Found
 921       if (!is_instance && (at->isa_oopptr() == NULL ||
 922                            !at->is_oopptr()->is_known_instance())) {
 923         break; // Do not skip store to general memory slice.
 924       }
 925       result = result->in(MemNode::Memory);
 926     }
 927     if (!is_instance)
 928       continue;  // don't search further for non-instance types
 929     // skip over a call which does not affect this memory slice
 930     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
 931       Node *proj_in = result->in(0);
 932       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
 933         break;  // hit one of our sentinels
 934       } else if (proj_in->is_Call()) {
 935         CallNode *call = proj_in->as_Call();
 936         if (!call->may_modify(toop, phase)) {
 937           result = call->in(TypeFunc::Memory);
 938         }
 939       } else if (proj_in->is_Initialize()) {
 940         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
 941         // Stop if this is the initialization for the object instance which
 942         // which contains this memory slice, otherwise skip over it.
 943         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
 944           result = proj_in->in(TypeFunc::Memory);
 945         }
 946       } else if (proj_in->is_MemBar()) {
 947         result = proj_in->in(TypeFunc::Memory);
 948       }
 949     } else if (result->is_MergeMem()) {
 950       MergeMemNode *mmem = result->as_MergeMem();
 951       result = step_through_mergemem(mmem, alias_idx, toop);
 952       if (result == mmem->base_memory()) {
 953         // Didn't find instance memory, search through general slice recursively.
 954         result = mmem->memory_at(C->get_general_index(alias_idx));
 955         result = find_inst_mem(result, alias_idx, orig_phis, phase);
 956         if (C->failing()) {
 957           return NULL;
 958         }
 959         mmem->set_memory_at(alias_idx, result);
 960       }
 961     } else if (result->is_Phi() &&
 962                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
 963       Node *un = result->as_Phi()->unique_input(phase);
 964       if (un != NULL) {
 965         orig_phis.append_if_missing(result->as_Phi());
 966         result = un;
 967       } else {
 968         break;
 969       }
 970     } else if (result->is_ClearArray()) {
 971       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), phase)) {
 972         // Can not bypass initialization of the instance
 973         // we are looking for.
 974         break;
 975       }
 976       // Otherwise skip it (the call updated 'result' value).
 977     } else if (result->Opcode() == Op_SCMemProj) {
 978       assert(result->in(0)->is_LoadStore(), "sanity");
 979       const Type *at = phase->type(result->in(0)->in(MemNode::Address));
 980       if (at != Type::TOP) {
 981         assert (at->isa_ptr() != NULL, "pointer type required.");
 982         int idx = C->get_alias_index(at->is_ptr());
 983         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
 984         break;
 985       }
 986       result = result->in(0)->in(MemNode::Memory);
 987     }
 988   }
 989   if (result->is_Phi()) {
 990     PhiNode *mphi = result->as_Phi();
 991     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
 992     const TypePtr *t = mphi->adr_type();
 993     if (!is_instance) {
 994       // Push all non-instance Phis on the orig_phis worklist to update inputs
 995       // during Phase 4 if needed.
 996       orig_phis.append_if_missing(mphi);
 997     } else if (C->get_alias_index(t) != alias_idx) {
 998       // Create a new Phi with the specified alias index type.
 999       result = split_memory_phi(mphi, alias_idx, orig_phis, phase);
1000     }
1001   }
1002   // the result is either MemNode, PhiNode, InitializeNode.
1003   return result;
1004 }
1005 
1006 //
1007 //  Convert the types of unescaped object to instance types where possible,
1008 //  propagate the new type information through the graph, and update memory
1009 //  edges and MergeMem inputs to reflect the new type.
1010 //
1011 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
1012 //  The processing is done in 4 phases:
1013 //
1014 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
1015 //            types for the CheckCastPP for allocations where possible.
1016 //            Propagate the the new types through users as follows:
1017 //               casts and Phi:  push users on alloc_worklist
1018 //               AddP:  cast Base and Address inputs to the instance type
1019 //                      push any AddP users on alloc_worklist and push any memnode
1020 //                      users onto memnode_worklist.
1021 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
1022 //            search the Memory chain for a store with the appropriate type
1023 //            address type.  If a Phi is found, create a new version with
1024 //            the appropriate memory slices from each of the Phi inputs.
1025 //            For stores, process the users as follows:
1026 //               MemNode:  push on memnode_worklist
1027 //               MergeMem: push on mergemem_worklist
1028 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
1029 //            moving the first node encountered of each  instance type to the
1030 //            the input corresponding to its alias index.
1031 //            appropriate memory slice.
1032 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
1033 //
1034 // In the following example, the CheckCastPP nodes are the cast of allocation
1035 // results and the allocation of node 29 is unescaped and eligible to be an
1036 // instance type.
1037 //
1038 // We start with:
1039 //
1040 //     7 Parm #memory
1041 //    10  ConI  "12"
1042 //    19  CheckCastPP   "Foo"
1043 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
1044 //    29  CheckCastPP   "Foo"
1045 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
1046 //
1047 //    40  StoreP  25   7  20   ... alias_index=4
1048 //    50  StoreP  35  40  30   ... alias_index=4
1049 //    60  StoreP  45  50  20   ... alias_index=4
1050 //    70  LoadP    _  60  30   ... alias_index=4
1051 //    80  Phi     75  50  60   Memory alias_index=4
1052 //    90  LoadP    _  80  30   ... alias_index=4
1053 //   100  LoadP    _  80  20   ... alias_index=4
1054 //
1055 //
1056 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
1057 // and creating a new alias index for node 30.  This gives:
1058 //
1059 //     7 Parm #memory
1060 //    10  ConI  "12"
1061 //    19  CheckCastPP   "Foo"
1062 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
1063 //    29  CheckCastPP   "Foo"  iid=24
1064 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
1065 //
1066 //    40  StoreP  25   7  20   ... alias_index=4
1067 //    50  StoreP  35  40  30   ... alias_index=6
1068 //    60  StoreP  45  50  20   ... alias_index=4
1069 //    70  LoadP    _  60  30   ... alias_index=6
1070 //    80  Phi     75  50  60   Memory alias_index=4
1071 //    90  LoadP    _  80  30   ... alias_index=6
1072 //   100  LoadP    _  80  20   ... alias_index=4
1073 //
1074 // In phase 2, new memory inputs are computed for the loads and stores,
1075 // And a new version of the phi is created.  In phase 4, the inputs to
1076 // node 80 are updated and then the memory nodes are updated with the
1077 // values computed in phase 2.  This results in:
1078 //
1079 //     7 Parm #memory
1080 //    10  ConI  "12"
1081 //    19  CheckCastPP   "Foo"
1082 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
1083 //    29  CheckCastPP   "Foo"  iid=24
1084 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
1085 //
1086 //    40  StoreP  25  7   20   ... alias_index=4
1087 //    50  StoreP  35  7   30   ... alias_index=6
1088 //    60  StoreP  45  40  20   ... alias_index=4
1089 //    70  LoadP    _  50  30   ... alias_index=6
1090 //    80  Phi     75  40  60   Memory alias_index=4
1091 //   120  Phi     75  50  50   Memory alias_index=6
1092 //    90  LoadP    _ 120  30   ... alias_index=6
1093 //   100  LoadP    _  80  20   ... alias_index=4
1094 //
1095 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {
1096   GrowableArray<Node *>  memnode_worklist;
1097   GrowableArray<PhiNode *>  orig_phis;
1098 
1099   PhaseIterGVN  *igvn = _igvn;
1100   uint new_index_start = (uint) _compile->num_alias_types();
1101   Arena* arena = Thread::current()->resource_area();
1102   VectorSet visited(arena);
1103 
1104   ideal_nodes.clear(); // Reset for use with set_map/get_map.
1105 
1106   uint unique_old = _compile->unique();
1107 
1108   //  Phase 1:  Process possible allocations from alloc_worklist.
1109   //  Create instance types for the CheckCastPP for allocations where possible.
1110   //
1111   // (Note: don't forget to change the order of the second AddP node on
1112   //  the alloc_worklist if the order of the worklist processing is changed,
1113   //  see the comment in find_second_addp().)
1114   //
1115   while (alloc_worklist.length() != 0) {
1116     Node *n = alloc_worklist.pop();
1117     uint ni = n->_idx;
1118     if (n->is_Call()) {
1119       CallNode *alloc = n->as_Call();
1120       // copy escape information to call node
1121       PointsToNode* ptn = ptnode_adr(alloc->_idx);
1122       PointsToNode::EscapeState es = ptn->escape_state();
1123       // We have an allocation or call which returns a Java object,
1124       // see if it is unescaped.
1125       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
1126         continue;
1127 
1128       // Find CheckCastPP for the allocate or for the return value of a call
1129       n = alloc->result_cast();
1130       if (n == NULL) {            // No uses except Initialize node
1131         if (alloc->is_Allocate()) {
1132           // Set the scalar_replaceable flag for allocation
1133           // so it could be eliminated if it has no uses.
1134           alloc->as_Allocate()->_is_scalar_replaceable = true;
1135         }
1136         continue;
1137       }
1138       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
1139         assert(!alloc->is_Allocate(), "allocation should have unique type");
1140         continue;
1141       }
1142 
1143       // The inline code for Object.clone() casts the allocation result to
1144       // java.lang.Object and then to the actual type of the allocated
1145       // object. Detect this case and use the second cast.
1146       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
1147       // the allocation result is cast to java.lang.Object and then
1148       // to the actual Array type.
1149       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
1150           && (alloc->is_AllocateArray() ||
1151               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
1152         Node *cast2 = NULL;
1153         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1154           Node *use = n->fast_out(i);
1155           if (use->is_CheckCastPP()) {
1156             cast2 = use;
1157             break;
1158           }
1159         }
1160         if (cast2 != NULL) {
1161           n = cast2;
1162         } else {
1163           // Non-scalar replaceable if the allocation type is unknown statically
1164           // (reflection allocation), the object can't be restored during
1165           // deoptimization without precise type.
1166           continue;
1167         }
1168       }
1169       if (alloc->is_Allocate()) {
1170         // Set the scalar_replaceable flag for allocation
1171         // so it could be eliminated.
1172         alloc->as_Allocate()->_is_scalar_replaceable = true;
1173       }
1174       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
1175       // in order for an object to be scalar-replaceable, it must be:
1176       //   - a direct allocation (not a call returning an object)
1177       //   - non-escaping
1178       //   - eligible to be a unique type
1179       //   - not determined to be ineligible by escape analysis
1180       set_map(alloc, n);
1181       set_map(n, alloc);
1182       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
1183       if (t == NULL)
1184         continue;  // not a TypeOopPtr
1185       const TypeOopPtr* tinst = t->cast_to_exactness(true)->is_oopptr()->cast_to_instance_id(ni);
1186       igvn->hash_delete(n);
1187       igvn->set_type(n,  tinst);
1188       n->raise_bottom_type(tinst);
1189       igvn->hash_insert(n);
1190       record_for_optimizer(n);
1191       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
1192 
1193         // First, put on the worklist all Field edges from Connection Graph
1194         // which is more accurate then putting immediate users from Ideal Graph.
1195         for (uint e = 0; e < ptn->edge_count(); e++) {
1196           PointsToNode* tgt = ptn->edge(e);
1197           Node* use = tgt->ideal_node();
1198           assert(tgt->is_Field() && use->is_AddP(),
1199                  "only AddP nodes are Field edges in CG");
1200           if (use->outcnt() > 0) { // Don't process dead nodes
1201             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
1202             if (addp2 != NULL) {
1203               assert(alloc->is_AllocateArray(),"array allocation was expected");
1204               alloc_worklist.append_if_missing(addp2);
1205             }
1206             alloc_worklist.append_if_missing(use);
1207           }
1208         }
1209 
1210         // An allocation may have an Initialize which has raw stores. Scan
1211         // the users of the raw allocation result and push AddP users
1212         // on alloc_worklist.
1213         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
1214         assert (raw_result != NULL, "must have an allocation result");
1215         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
1216           Node *use = raw_result->fast_out(i);
1217           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
1218             Node* addp2 = find_second_addp(use, raw_result);
1219             if (addp2 != NULL) {
1220               assert(alloc->is_AllocateArray(),"array allocation was expected");
1221               alloc_worklist.append_if_missing(addp2);
1222             }
1223             alloc_worklist.append_if_missing(use);
1224           } else if (use->is_MemBar()) {
1225             memnode_worklist.append_if_missing(use);
1226           }
1227         }
1228       }
1229     } else if (n->is_AddP()) {
1230       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
1231       if (jobj == NULL || jobj == phantom_obj) {
1232 #ifdef ASSERT
1233         ptnode_adr(get_addp_base(n)->_idx)->dump();
1234         ptnode_adr(n->_idx)->dump();
1235         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
1236 #endif
1237         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
1238         return;
1239       }
1240       Node *base = get_map(jobj->idx());  // CheckCastPP node
1241       if (!split_AddP(n, base, igvn)) continue; // wrong type from dead path
1242     } else if (n->is_Phi() ||
1243                n->is_CheckCastPP() ||
1244                n->is_EncodeP() ||
1245                n->is_DecodeN() ||
1246                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
1247       if (visited.test_set(n->_idx)) {
1248         assert(n->is_Phi(), "loops only through Phi's");
1249         continue;  // already processed
1250       }
1251       JavaObjectNode* jobj = unique_java_object(n);
1252       if (jobj == NULL || jobj == phantom_obj) {
1253 #ifdef ASSERT
1254         ptnode_adr(n->_idx)->dump();
1255         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
1256 #endif
1257         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
1258         return;
1259       } else {
1260         Node *val = get_map(jobj->idx());   // CheckCastPP node
1261         TypeNode *tn = n->as_Type();
1262         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
1263         assert(tinst != NULL && tinst->is_known_instance() &&
1264                tinst->instance_id() == jobj->idx() , "instance type expected.");
1265 
1266         const Type *tn_type = igvn->type(tn);
1267         const TypeOopPtr *tn_t;
1268         if (tn_type->isa_narrowoop()) {
1269           tn_t = tn_type->make_ptr()->isa_oopptr();
1270         } else {
1271           tn_t = tn_type->isa_oopptr();
1272         }
1273 
1274         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
1275           if (tn_type->isa_narrowoop()) {
1276             tn_type = tinst->make_narrowoop();
1277           } else {
1278             tn_type = tinst;
1279           }
1280           igvn->hash_delete(tn);
1281           igvn->set_type(tn, tn_type);
1282           tn->set_type(tn_type);
1283           igvn->hash_insert(tn);
1284           record_for_optimizer(n);
1285         } else {
1286           assert(tn_type == TypePtr::NULL_PTR ||
1287                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
1288                  "unexpected type");
1289           continue; // Skip dead path with different type
1290         }
1291       }
1292     } else {
1293       debug_only(n->dump();)
1294       assert(false, "EA: unexpected node");
1295       continue;
1296     }
1297     // push allocation's users on appropriate worklist
1298     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1299       Node *use = n->fast_out(i);
1300       if(use->is_Mem() && use->in(MemNode::Address) == n) {
1301         // Load/store to instance's field
1302         memnode_worklist.append_if_missing(use);
1303       } else if (use->is_MemBar()) {
1304         memnode_worklist.append_if_missing(use);
1305       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
1306         Node* addp2 = find_second_addp(use, n);
1307         if (addp2 != NULL) {
1308           alloc_worklist.append_if_missing(addp2);
1309         }
1310         alloc_worklist.append_if_missing(use);
1311       } else if (use->is_Phi() ||
1312                  use->is_CheckCastPP() ||
1313                  use->is_EncodeP() ||
1314                  use->is_DecodeN() ||
1315                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
1316         alloc_worklist.append_if_missing(use);
1317 #ifdef ASSERT
1318       } else if (use->is_Mem()) {
1319         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
1320       } else if (use->is_MergeMem()) {
1321         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
1322       } else if (use->is_SafePoint()) {
1323         // Look for MergeMem nodes for calls which reference unique allocation
1324         // (through CheckCastPP nodes) even for debug info.
1325         Node* m = use->in(TypeFunc::Memory);
1326         if (m->is_MergeMem()) {
1327           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
1328         }
1329       } else {
1330         uint op = use->Opcode();
1331         if (!(op == Op_CmpP || op == Op_Conv2B ||
1332               op == Op_CastP2X || op == Op_StoreCM ||
1333               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
1334               op == Op_StrEquals || op == Op_StrIndexOf)) {
1335           n->dump();
1336           use->dump();
1337           assert(false, "EA: missing allocation reference path");
1338         }
1339 #endif
1340       }
1341     }
1342 
1343   }
1344   // New alias types were created in split_AddP().
1345   uint new_index_end = (uint) _compile->num_alias_types();
1346 
1347   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
1348 
1349   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
1350   //            compute new values for Memory inputs  (the Memory inputs are not
1351   //            actually updated until phase 4.)
1352   if (memnode_worklist.length() == 0)
1353     return;  // nothing to do
1354 
1355   while (memnode_worklist.length() != 0) {
1356     Node *n = memnode_worklist.pop();
1357     if (visited.test_set(n->_idx))
1358       continue;
1359     if (n->is_Phi() || n->is_ClearArray()) {
1360       // we don't need to do anything, but the users must be pushed
1361     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
1362       // we don't need to do anything, but the users must be pushed
1363       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
1364       if (n == NULL)
1365         continue;
1366     } else {
1367       assert(n->is_Mem(), "memory node required.");
1368       Node *addr = n->in(MemNode::Address);
1369       const Type *addr_t = igvn->type(addr);
1370       if (addr_t == Type::TOP)
1371         continue;
1372       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
1373       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
1374       assert ((uint)alias_idx < new_index_end, "wrong alias index");
1375       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis, igvn);
1376       if (_compile->failing()) {
1377         return;
1378       }
1379       if (mem != n->in(MemNode::Memory)) {
1380         // We delay the memory edge update since we need old one in
1381         // MergeMem code below when instances memory slices are separated.
1382         set_map(n, mem);
1383       }
1384       if (n->is_Load()) {
1385         continue;  // don't push users
1386       } else if (n->is_LoadStore()) {
1387         // get the memory projection
1388         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1389           Node *use = n->fast_out(i);
1390           if (use->Opcode() == Op_SCMemProj) {
1391             n = use;
1392             break;
1393           }
1394         }
1395         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
1396       }
1397     }
1398     // push user on appropriate worklist
1399     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1400       Node *use = n->fast_out(i);
1401       if (use->is_Phi() || use->is_ClearArray()) {
1402         memnode_worklist.append_if_missing(use);
1403       } else if(use->is_Mem() && use->in(MemNode::Memory) == n) {
1404         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
1405           continue;
1406         memnode_worklist.append_if_missing(use);
1407       } else if (use->is_MemBar()) {
1408         memnode_worklist.append_if_missing(use);
1409 #ifdef ASSERT
1410       } else if(use->is_Mem()) {
1411         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
1412       } else if (use->is_MergeMem()) {
1413         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
1414       } else {
1415         uint op = use->Opcode();
1416         if (!(op == Op_StoreCM ||
1417               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
1418                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
1419               op == Op_AryEq || op == Op_StrComp ||
1420               op == Op_StrEquals || op == Op_StrIndexOf)) {
1421           n->dump();
1422           use->dump();
1423           assert(false, "EA: missing memory path");
1424         }
1425 #endif
1426       }
1427     }
1428   }
1429 
1430   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
1431   //            Walk each memory slice moving the first node encountered of each
1432   //            instance type to the the input corresponding to its alias index.
1433   uint length = _mergemem_worklist.length();
1434   for( uint next = 0; next < length; ++next ) {
1435     MergeMemNode* nmm = _mergemem_worklist.at(next);
1436     assert(!visited.test_set(nmm->_idx), "should not be visited before");
1437     // Note: we don't want to use MergeMemStream here because we only want to
1438     // scan inputs which exist at the start, not ones we add during processing.
1439     // Note 2: MergeMem may already contains instance memory slices added
1440     // during find_inst_mem() call when memory nodes were processed above.
1441     igvn->hash_delete(nmm);
1442     uint nslices = nmm->req();
1443     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
1444       Node* mem = nmm->in(i);
1445       Node* cur = NULL;
1446       if (mem == NULL || mem->is_top())
1447         continue;
1448       // First, update mergemem by moving memory nodes to corresponding slices
1449       // if their type became more precise since this mergemem was created.
1450       while (mem->is_Mem()) {
1451         const Type *at = igvn->type(mem->in(MemNode::Address));
1452         if (at != Type::TOP) {
1453           assert (at->isa_ptr() != NULL, "pointer type required.");
1454           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
1455           if (idx == i) {
1456             if (cur == NULL)
1457               cur = mem;
1458           } else {
1459             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
1460               nmm->set_memory_at(idx, mem);
1461             }
1462           }
1463         }
1464         mem = mem->in(MemNode::Memory);
1465       }
1466       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
1467       // Find any instance of the current type if we haven't encountered
1468       // already a memory slice of the instance along the memory chain.
1469       for (uint ni = new_index_start; ni < new_index_end; ni++) {
1470         if((uint)_compile->get_general_index(ni) == i) {
1471           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
1472           if (nmm->is_empty_memory(m)) {
1473             Node* result = find_inst_mem(mem, ni, orig_phis, igvn);
1474             if (_compile->failing()) {
1475               return;
1476             }
1477             nmm->set_memory_at(ni, result);
1478           }
1479         }
1480       }
1481     }
1482     // Find the rest of instances values
1483     for (uint ni = new_index_start; ni < new_index_end; ni++) {
1484       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
1485       Node* result = step_through_mergemem(nmm, ni, tinst);
1486       if (result == nmm->base_memory()) {
1487         // Didn't find instance memory, search through general slice recursively.
1488         result = nmm->memory_at(_compile->get_general_index(ni));
1489         result = find_inst_mem(result, ni, orig_phis, igvn);
1490         if (_compile->failing()) {
1491           return;
1492         }
1493         nmm->set_memory_at(ni, result);
1494       }
1495     }
1496     igvn->hash_insert(nmm);
1497     record_for_optimizer(nmm);
1498   }
1499 
1500   //  Phase 4:  Update the inputs of non-instance memory Phis and
1501   //            the Memory input of memnodes
1502   // First update the inputs of any non-instance Phi's from
1503   // which we split out an instance Phi.  Note we don't have
1504   // to recursively process Phi's encounted on the input memory
1505   // chains as is done in split_memory_phi() since they  will
1506   // also be processed here.
1507   for (int j = 0; j < orig_phis.length(); j++) {
1508     PhiNode *phi = orig_phis.at(j);
1509     int alias_idx = _compile->get_alias_index(phi->adr_type());
1510     igvn->hash_delete(phi);
1511     for (uint i = 1; i < phi->req(); i++) {
1512       Node *mem = phi->in(i);
1513       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis, igvn);
1514       if (_compile->failing()) {
1515         return;
1516       }
1517       if (mem != new_mem) {
1518         phi->set_req(i, new_mem);
1519       }
1520     }
1521     igvn->hash_insert(phi);
1522     record_for_optimizer(phi);
1523   }
1524 
1525   // Update the memory inputs of MemNodes with the value we computed
1526   // in Phase 2 and move stores memory users to corresponding memory slices.
1527 
1528   // Disable memory split verification code until the fix for 6984348.
1529   // Currently it produces false negative results since it does not cover all cases.
1530 #if 0 // ifdef ASSERT
1531   visited.Reset();
1532   Node_Stack old_mems(arena, _compile->unique() >> 2);
1533 #endif
1534   for (uint i = 0; i < ideal_nodes.size(); i++) {
1535     Node*    n = ideal_nodes.at(i);
1536     Node* nmem = get_map(n->_idx);
1537     assert(nmem != NULL, "sanity");
1538     if (n->is_Mem()) {
1539 #if 0 // ifdef ASSERT
1540       Node* old_mem = n->in(MemNode::Memory);
1541       if (!visited.test_set(old_mem->_idx)) {
1542         old_mems.push(old_mem, old_mem->outcnt());
1543       }
1544 #endif
1545       assert(n->in(MemNode::Memory) != nmem, "sanity");
1546       if (!n->is_Load()) {
1547         // Move memory users of a store first.
1548         move_inst_mem(n, orig_phis, igvn);
1549       }
1550       // Now update memory input
1551       igvn->hash_delete(n);
1552       n->set_req(MemNode::Memory, nmem);
1553       igvn->hash_insert(n);
1554       record_for_optimizer(n);
1555     } else {
1556       assert(n->is_Allocate() || n->is_CheckCastPP() ||
1557              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
1558     }
1559   }
1560 #if 0 // ifdef ASSERT
1561   // Verify that memory was split correctly
1562   while (old_mems.is_nonempty()) {
1563     Node* old_mem = old_mems.node();
1564     uint  old_cnt = old_mems.index();
1565     old_mems.pop();
1566     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
1567   }
1568 #endif
1569 }
1570 
1571 bool ConnectionGraph::has_candidates(Compile *C) {
1572   // EA brings benefits only when the code has allocations and/or locks which
1573   // are represented by ideal Macro nodes.
1574   int cnt = C->macro_count();
1575   for( int i=0; i < cnt; i++ ) {
1576     Node *n = C->macro_node(i);
1577     if ( n->is_Allocate() )
1578       return true;
1579     if( n->is_Lock() ) {
1580       Node* obj = n->as_Lock()->obj_node()->uncast();
1581       if( !(obj->is_Parm() || obj->is_Con()) )
1582         return true;
1583     }
1584   }
1585   return false;
1586 }
1587 
1588 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
1589   Compile::TracePhase t2("escapeAnalysis", &Phase::_t_escapeAnalysis, true);
1590 
1591   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
1592   // to create space for them in ConnectionGraph::_nodes[].
1593   Node* oop_null = igvn->zerocon(T_OBJECT);
1594   Node* noop_null = igvn->zerocon(T_NARROWOOP);
1595 
1596   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
1597   // Perform escape analysis
1598   if (congraph->compute_escape()) {
1599     // There are non escaping objects.
1600     C->set_congraph(congraph);
1601   }
1602 
1603   // Cleanup.
1604   if (oop_null->outcnt() == 0)
1605     igvn->hash_delete(oop_null);
1606   if (noop_null->outcnt() == 0)
1607     igvn->hash_delete(noop_null);
1608 }
1609 
1610 bool ConnectionGraph::compute_escape() {
1611   Compile* C = _compile;
1612   PhaseGVN* igvn = _igvn;
1613 
1614   // 1. Populate Connection Graph (CG) with PointsTo nodes.
1615 
1616   ideal_nodes.map(C->unique(), NULL);  // preallocate space
1617 
1618   // Initialize worklist
1619   if (C->root() != NULL) {
1620     ideal_nodes.push(C->root());
1621   }
1622 
1623   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
1624 
1625   Unique_Node_List delayed_worklist;
1626   GrowableArray<Node*> alloc_worklist;
1627   GrowableArray<Node*> ptr_cmp_worklist;
1628   GrowableArray<Node*> storestore_worklist;
1629 
1630   GrowableArray<PointsToNode*>   ptnodes_worklist;
1631   GrowableArray<JavaObjectNode*> java_objects_worklist;
1632   GrowableArray<JavaObjectNode*> non_escaped_worklist;
1633   GrowableArray<FieldNode*>      oop_fields_worklist;
1634 
1635   { Compile::TracePhase t3("connectionGraph", &Phase::_t_connectionGraph, true);
1636 
1637   // Push all useful nodes onto CG list and set their type.
1638   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
1639     Node* n = ideal_nodes.at(next);
1640 
1641     // It is called only once per node since ideal_nodes is Unique_Node list.
1642     build_connection_graph(n, &delayed_worklist, igvn);
1643 
1644     PointsToNode* ptn = ptnode_adr(n->_idx);
1645     if (ptn != NULL) {
1646       ptnodes_worklist.append(ptn);
1647       if (ptn->is_JavaObject()) {
1648         java_objects_worklist.append(ptn->as_JavaObject());
1649         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
1650             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
1651           // Only allocations and java static calls results are interesting.
1652           non_escaped_worklist.append(ptn->as_JavaObject());
1653         }
1654       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
1655         oop_fields_worklist.append(ptn->as_Field());
1656       }
1657     }
1658     if (n->is_MergeMem()) {
1659       // Collect all MergeMem nodes to add memory slices for
1660       // scalar replaceable objects in split_unique_types().
1661       _mergemem_worklist.append(n->as_MergeMem());
1662     } else if (OptimizePtrCompare && n->is_Cmp() &&
1663                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
1664       // Compare pointers nodes
1665       ptr_cmp_worklist.append(n);
1666     } else if (n->is_MemBarStoreStore()) {
1667       // Collect all MemBarStoreStore nodes so that depending on the
1668       // escape status of the associated Allocate node some of them
1669       // may be eliminated.
1670       storestore_worklist.append(n);
1671 #ifdef ASSERT
1672     } else if(n->is_AddP()) {
1673       // Collect address nodes. Use them during stage 3 below
1674       // to build initial connection graph field edges.
1675       addp_worklist.append(n);
1676 #endif
1677     }
1678     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1679       Node* m = n->fast_out(i);   // Get user
1680       ideal_nodes.push(m);
1681     }
1682   }
1683 
1684   if (non_escaped_worklist.length() == 0) {
1685     _collecting = false;
1686     return false; // Nothing to do.
1687   }
1688 
1689   // Add final simple edges.
1690   while(delayed_worklist.size() > 0) {
1691     Node* n = delayed_worklist.pop();
1692     build_connection_graph(n, NULL, igvn);
1693   }
1694 
1695   uint ptnodes_length = ptnodes_worklist.length();
1696 
1697 #ifdef ASSERT
1698   if (VerifyConnectionGraph) {
1699     // Verify that no new simple edges could be created and all
1700     // local vars has edges.
1701     _verify = true;
1702     for (uint next = 0; next < ptnodes_length; ++next) {
1703       PointsToNode* ptn = ptnodes_worklist.at(next);
1704       build_connection_graph(ptn->ideal_node(), NULL, igvn);
1705       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
1706         ptn->dump();
1707         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
1708       }
1709     }
1710     _verify = false;
1711   }
1712 #endif
1713 
1714   // 2. Finish Graph construction.
1715 
1716   // Normally only 1-3 passes needed to build
1717   // Connection Graph depending on graph complexity.
1718   // Observed 8 passes in jvm2008 compiler.compiler.
1719   // Set limit to 20 to catch situation when something
1720   // did go wrong and recompile the method without EA.
1721   // Also limit build time to 30 sec (60 in debug VM).
1722 
1723 #define CG_BUILD_ITER_LIMIT 20
1724 
1725 #ifdef ASSERT
1726 #define CG_BUILD_TIME_LIMIT 60.0
1727 #else
1728 #define CG_BUILD_TIME_LIMIT 30.0
1729 #endif
1730 
1731   int iterations = 0;
1732 
1733   // Propagate GlobalEscape and ArgEscape escape states
1734   // and check that we still have non escaped objects.
1735   // The method pushs on _worklist Field nodes which reference phantom_object.
1736   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1737     _collecting = false;
1738     return false; // Nothing to do.
1739   }
1740 
1741   // Propagate references to all JavaObject nodes.
1742   uint java_objects_length = java_objects_worklist.length();
1743 
1744   elapsedTimer time;
1745   int new_edges = 1;
1746   do {
1747     while ((new_edges > 0) &&
1748           (iterations++   < CG_BUILD_ITER_LIMIT) &&
1749           (time.seconds() < CG_BUILD_TIME_LIMIT)) {
1750       time.start();
1751       new_edges = 0;
1752       // Propagate references to phantom_object for nodes pushed on _worklist
1753       // by find_non_escaped_objects() and find_field_value().
1754       new_edges += add_java_object_edges(phantom_obj, false);
1755       for (uint next = 0; next < java_objects_length; ++next) {
1756         JavaObjectNode* ptn = java_objects_worklist.at(next);
1757         new_edges += add_java_object_edges(ptn, true);
1758       }
1759       if (new_edges > 0) {
1760         // Update escape states on each iteration if graph was updated.
1761         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1762           _collecting = false;
1763           return false; // Nothing to do.
1764         }
1765       }
1766       time.stop();
1767     }
1768 
1769     if ((iterations     < CG_BUILD_ITER_LIMIT) &&
1770         (time.seconds() < CG_BUILD_TIME_LIMIT)) {
1771       time.start();
1772       // Find fields which have unknown value.
1773       uint fields_length = oop_fields_worklist.length();
1774       for (uint next = 0; next < fields_length; next++) {
1775         FieldNode* field = oop_fields_worklist.at(next);
1776         if (field->edge_count() == 0) {
1777           new_edges += find_field_value(field);
1778           // This code may added new edges to phantom_object.
1779           // Need an other cycle to propagate references to phantom_object.
1780         }
1781       }
1782       time.stop();
1783     }
1784   } while (new_edges > 0);
1785 
1786   if ((iterations     >= CG_BUILD_ITER_LIMIT) ||
1787       (time.seconds() >= CG_BUILD_TIME_LIMIT)) {
1788     assert(false, err_msg("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1789            time.seconds(), iterations, nodes_size(), ptnodes_length));
1790     // Possible infinite build_connection_graph loop,
1791     // bailout (no changes to ideal graph were made).
1792     _collecting = false;
1793     return false;
1794   }
1795 
1796 #ifdef ASSERT
1797   if (Verbose && PrintEscapeAnalysis) {
1798     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1799                   iterations, nodes_size(), ptnodes_length);
1800   }
1801 #endif
1802 
1803 #undef CG_BUILD_ITER_LIMIT
1804 #undef CG_BUILD_TIME_LIMIT
1805 
1806 
1807   // 3. Find fields initialized by NULL for non escaped Allocations.
1808 
1809   uint non_escaped_length = non_escaped_worklist.length();
1810   for (uint next = 0; next < non_escaped_length; next++) {
1811     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1812     PointsToNode::EscapeState es = ptn->escape_state();
1813     assert(es <= PointsToNode::ArgEscape, "sanity");
1814 
1815     if (es == PointsToNode::NoEscape) {
1816       if (find_init_values(ptn, null_obj, igvn) > 0) {
1817         // Adding references to NULL object does not change escape states
1818         // since it does not escape. Also no fields are added to NULL object.
1819         add_java_object_edges(null_obj, false);
1820       }
1821     }
1822     Node* n = ptn->ideal_node();
1823     if (n->is_Allocate()) {
1824       // The object allocated by this Allocate node will never be
1825       // seen by an other thread. Mark it so that when it is
1826       // expanded no MemBarStoreStore is added.
1827       InitializeNode* ini = n->as_Allocate()->initialization();
1828       if (ini != NULL)
1829         ini->set_does_not_escape();
1830     }
1831   }
1832 
1833 #ifdef ASSERT
1834   if (VerifyConnectionGraph) {
1835     uint addp_length = addp_worklist.length();
1836     for (uint next = 0; next < addp_length; ++next ) {
1837       Node* n = addp_worklist.at(next);
1838       FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1839       if (field->is_oop()) {
1840         // Verify that field has all bases
1841         Node* base = get_addp_base(n);
1842         PointsToNode* ptn = ptnode_adr(base->_idx);
1843         if (ptn->is_JavaObject()) {
1844           assert(field->has_base(ptn->as_JavaObject()), "sanity");
1845         } else {
1846           assert(ptn->is_LocalVar(), "sanity");
1847           uint count = ptn->edge_count();
1848           for (uint i = 0; i < count; i++) {
1849             PointsToNode* e = ptn->edge(i);
1850             if (e->is_JavaObject()) {
1851               assert(field->has_base(e->as_JavaObject()), "sanity");
1852             }
1853           }
1854         }
1855         // Verify that all fields have initializing values.
1856         if (field->edge_count() == 0) {
1857           field->dump();
1858           assert(field->edge_count() > 0, "sanity");
1859         }
1860       }
1861     }
1862   }
1863 #endif
1864 
1865   // 4. Adjust scalar_replaceable state of nonescaping objects.
1866 
1867   for (uint next = 0; next < non_escaped_length; next++) {
1868     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1869     if (ptn->escape_state() == PointsToNode::NoEscape &&
1870         ptn->scalar_replaceable()) {
1871       adjust_scalar_replaceable_state(ptn);
1872 
1873       if (ptn->scalar_replaceable()) {
1874         // Push scalar replaceable allocations on alloc_worklist
1875         // for processing in split_unique_types().
1876         alloc_worklist.append(ptn->ideal_node());
1877       }
1878     }
1879   }
1880 
1881 #ifdef ASSERT
1882   if (VerifyConnectionGraph) {
1883     // Verify that graph is complete - no new edges could be added.
1884     new_edges = 0;
1885     for (uint next = 0; next < java_objects_length; ++next) {
1886       JavaObjectNode* ptn = java_objects_worklist.at(next);
1887       new_edges += add_java_object_edges(ptn, true);
1888     }
1889     assert(new_edges == 0, "graph was not complete");
1890 
1891     // Verify that escape state is final.
1892     uint length = non_escaped_worklist.length();
1893     find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1894     assert((non_escaped_length == (uint)non_escaped_worklist.length()) &&
1895            (non_escaped_length == length) &&
1896            (_worklist.length() == 0), "escape state was not final");
1897   }
1898 #endif
1899 
1900   _collecting = false;
1901   assert(C->unique() == nodes_size(), "there should be no new ideal nodes during ConnectionGraph build");
1902 
1903   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
1904          null_obj->edge_count() == 0 &&
1905          !null_obj->arraycopy_src() &&
1906          !null_obj->arraycopy_dst(), "sanity");
1907 
1908   } // TracePhase t3("connectionGraph")
1909 
1910   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
1911 
1912   if (EliminateLocks && has_non_escaping_obj) {
1913     // Mark locks before changing ideal graph.
1914     int cnt = C->macro_count();
1915     for( int i=0; i < cnt; i++ ) {
1916       Node *n = C->macro_node(i);
1917       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1918         AbstractLockNode* alock = n->as_AbstractLock();
1919         if (!alock->is_non_esc_obj()) {
1920           if (not_global_escape(alock->obj_node())) {
1921             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1922             // The lock could be marked eliminated by lock coarsening
1923             // code during first IGVN before EA. Replace coarsened flag
1924             // to eliminate all associated locks/unlocks.
1925             alock->set_non_esc_obj();
1926           }
1927         }
1928       }
1929     }
1930   }
1931 
1932   if (OptimizePtrCompare && has_non_escaping_obj) {
1933     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1934     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1935     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1936     // Optimize objects compare.
1937     while (ptr_cmp_worklist.length() != 0) {
1938       Node *n = ptr_cmp_worklist.pop();
1939       Node *res = optimize_ptr_compare(n);
1940       if (res != NULL) {
1941 #ifndef PRODUCT
1942         if (PrintOptimizePtrCompare) {
1943           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"));
1944           if (Verbose) {
1945             n->dump(1);
1946           }
1947         }
1948 #endif
1949         _igvn->replace_node(n, res);
1950       }
1951     }
1952     // cleanup
1953     if (_pcmp_neq->outcnt() == 0)
1954       igvn->hash_delete(_pcmp_neq);
1955     if (_pcmp_eq->outcnt()  == 0)
1956       igvn->hash_delete(_pcmp_eq);
1957   }
1958 
1959   // For MemBarStoreStore nodes added in library_call.cpp, check
1960   // escape status of associated AllocateNode and optimize out
1961   // MemBarStoreStore node if the allocated object never escapes.
1962   while (storestore_worklist.length() != 0) {
1963     Node *n = storestore_worklist.pop();
1964     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1965     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1966     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1967     PointsToNode::EscapeState es = ptnode_adr(alloc->_idx)->escape_state();
1968     if (es == PointsToNode::NoEscape || es == PointsToNode::ArgEscape) {
1969       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1970       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1971       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1972 
1973       _igvn->register_new_node_with_optimizer(mb);
1974       _igvn->replace_node(storestore, mb);
1975     }
1976   }
1977 
1978 #ifndef PRODUCT
1979   if (PrintEscapeAnalysis) {
1980     dump(ptnodes_worklist); // Dump ConnectionGraph
1981   }
1982 #endif
1983 
1984   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
1985 #ifdef ASSERT
1986   if (VerifyConnectionGraph) {
1987     uint alloc_length = alloc_worklist.length();
1988     for (uint next = 0; next < alloc_length; ++next) {
1989       Node* n = alloc_worklist.at(next);
1990       PointsToNode* ptn = ptnode_adr(n->_idx);
1991       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
1992     }
1993   }
1994 #endif
1995 
1996   if (has_scalar_replaceable_candidates &&
1997       C->AliasLevel() >= 3 && EliminateAllocations) {
1998 
1999     // Now use the escape information to create unique types for
2000     // scalar replaceable objects.
2001     split_unique_types(alloc_worklist);
2002 
2003     if (C->failing())  return false;
2004 
2005     C->print_method("After Escape Analysis", 2);
2006 
2007 #ifdef ASSERT
2008   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
2009     tty->print("=== No allocations eliminated for ");
2010     C->method()->print_short_name();
2011     if(!EliminateAllocations) {
2012       tty->print(" since EliminateAllocations is off ===");
2013     } else if(!has_scalar_replaceable_candidates) {
2014       tty->print(" since there are no scalar replaceable candidates ===");
2015     } else if(C->AliasLevel() < 3) {
2016       tty->print(" since AliasLevel < 3 ===");
2017     }
2018     tty->cr();
2019 #endif
2020   }
2021   return has_non_escaping_obj;
2022 }
2023 
2024 // Find fields which have unknown value.
2025 int ConnectionGraph::find_field_value(FieldNode* field) {
2026   // Escaped fields should have init value already.
2027   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
2028 
2029   int new_edges = 0;
2030 
2031   uint bcnt = field->base_count();
2032   for (uint i = 0; i < bcnt; i++) {
2033     PointsToNode* base = field->base(i);
2034     if (base->is_JavaObject()) {
2035       // Skip Allocate's fields which will be processed later.
2036       if (base->ideal_node()->is_Allocate())
2037         return 0;
2038       assert(base == null_obj, "only NULL ptr base expected here");
2039     }
2040   }
2041   if (add_edge(field, phantom_obj)) {
2042     // New edge was added
2043     new_edges++;
2044     add_field_uses_to_worklist(field);
2045   }
2046   return new_edges;
2047 }
2048 
2049 // Find fields initializing values for allocations.
2050 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
2051   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
2052 
2053   int new_edges = 0;
2054 
2055   Node* alloc = pta->ideal_node();
2056 
2057   if (init_val == phantom_obj) {
2058     // Do nothing for Allocate nodes since its fields values are "known".
2059     if (alloc->is_Allocate())
2060       return 0;
2061 
2062     assert(alloc->as_CallStaticJava(), "sanity");
2063 #ifdef ASSERT
2064     if (alloc->as_CallStaticJava()->method() == NULL) {
2065       const char* name = alloc->as_CallStaticJava()->_name;
2066       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
2067     }
2068 #endif
2069 
2070     // Non-escaped allocation returned from Java or runtime call have
2071     // unknown values in fields.
2072     uint cnt = pta->edge_count();
2073     for (uint i = 0; i < cnt; i++) {
2074       PointsToNode* ptn = pta->edge(i);
2075       if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
2076         if (add_edge(ptn, phantom_obj)) {
2077           // New edge was added
2078           new_edges++;
2079           add_field_uses_to_worklist(ptn->as_Field());
2080         }
2081       }
2082     }
2083     return new_edges;
2084   }
2085 
2086   assert(init_val == null_obj, "sanity");
2087   // Do nothing for Call nodes since its fields values are unknown.
2088   if (!alloc->is_Allocate())
2089     return 0;
2090 
2091   InitializeNode* ini = alloc->as_Allocate()->initialization();
2092 
2093   Compile* C = _compile;
2094   bool visited_bottom_offset = false;
2095   GrowableArray<int> offsets_worklist;
2096 
2097   // Check if a oop field's initializing value is recorded and add
2098   // a corresponding NULL if field's value if it is not recorded.
2099   // Connection Graph does not record a default initialization by NULL
2100   // captured by Initialize node.
2101   //
2102   uint ae_cnt = pta->edge_count();
2103   for (uint ei = 0; ei < ae_cnt; ei++) {
2104 
2105     PointsToNode* ptn = pta->edge(ei); // Field (AddP)
2106     if (!ptn->is_Field() || !ptn->as_Field()->is_oop())
2107       continue; // Not oop field
2108 
2109     int offset = ptn->as_Field()->offset();
2110     if (offset == Type::OffsetBot) {
2111       if (!visited_bottom_offset) {
2112         // OffsetBot is used to reference array's element,
2113         // always add reference to NULL to all Field nodes since we don't
2114         // known which element is referenced.
2115         if (add_edge(ptn, null_obj)) {
2116           // New edge was added
2117           new_edges++;
2118           add_field_uses_to_worklist(ptn->as_Field());
2119           visited_bottom_offset = true;
2120         }
2121       }
2122     } else {
2123       // Check only oop fields.
2124       const Type* adr_type = ptn->ideal_node()->as_AddP()->bottom_type();
2125       if (adr_type->isa_rawptr()) {
2126 #ifdef ASSERT
2127         // Raw pointers are used for initializing stores so skip it
2128         // since it should be recorded already
2129         Node* base = get_addp_base(ptn->ideal_node());
2130         assert(adr_type->isa_rawptr() && base->is_Proj() &&
2131                (base->in(0) == alloc),"unexpected pointer type");
2132 #endif
2133         continue;
2134       }
2135       if (!offsets_worklist.contains(offset)) {
2136         offsets_worklist.append(offset);
2137         Node* value = NULL;
2138         if (ini != NULL) {
2139           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_OBJECT;
2140           Node* store = ini->find_captured_store(offset, type2aelembytes(ft), phase);
2141           if (store != NULL && store->is_Store()) {
2142             value = store->in(MemNode::ValueIn);
2143           } else {
2144             // There could be initializing stores which follow allocation.
2145             // For example, a volatile field store is not collected
2146             // by Initialize node.
2147             //
2148             // Need to check for dependent loads to separate such stores from
2149             // stores which follow loads. For now, add initial value NULL so
2150             // that compare pointers optimization works correctly.
2151           }
2152         }
2153         if (value == NULL) {
2154           // A field's initializing value was not recorded. Add NULL.
2155           if (add_edge(ptn, null_obj)) {
2156             // New edge was added
2157             new_edges++;
2158             add_field_uses_to_worklist(ptn->as_Field());
2159           }
2160         }
2161       }
2162     }
2163   }
2164   return new_edges;
2165 }
2166 
2167 // Adjust scalar_replaceable state after Connection Graph is built.
2168 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
2169   // Search for non escaped objects which are not scalar replaceable
2170   // and mark them to propagate the state to referenced objects.
2171 
2172   // 1. An object is not scalar replaceable if the field into which it is
2173   // stored has unknown offset (stored into unknown element of an array).
2174   //
2175   uint count = jobj->use_count();
2176   for (uint i = 0; i < count; i++) {
2177     PointsToNode* use = jobj->use(i);
2178     assert(!use->is_Arraycopy(), "sanity");
2179     if (use->is_Field()) {
2180       FieldNode* field = use->as_Field();
2181       assert(field->is_oop() && field->scalar_replaceable() &&
2182              field->fields_escape_state() == PointsToNode::NoEscape, "sanity");
2183       if (field->offset() == Type::OffsetBot) {
2184         jobj->set_scalar_replaceable(false);
2185         return;
2186       }
2187     }
2188     assert(use->is_Field() || use->is_LocalVar(), "sanity");
2189 
2190     // 2. An object is not scalar replaceable if it is merged with other objects.
2191     uint e_count = use->edge_count();
2192     for (uint j = 0; j < e_count; j++) {
2193       PointsToNode* ptn = use->edge(j);
2194       if (ptn->is_JavaObject() && ptn != jobj) {
2195         // Mark all objects.
2196         jobj->set_scalar_replaceable(false);
2197          ptn->set_scalar_replaceable(false);
2198       }
2199     }
2200     if (!jobj->scalar_replaceable()) {
2201       return;
2202     }
2203   }
2204 
2205   count = jobj->edge_count();
2206   for (uint j = 0; j < count; j++) {
2207     // Non escaped object should points only to fields.
2208     FieldNode* field = jobj->edge(j)->as_Field();
2209     int offset = field->as_Field()->offset();
2210 
2211     // 3. An object is not scalar replaceable if it has a field with unknown
2212     // offset (array's element is accessed in loop).
2213     if (offset == Type::OffsetBot) {
2214       jobj->set_scalar_replaceable(false);
2215       return;
2216     }
2217 
2218     // 4. Currently an object is not scalar replaceable if a LoadStore node
2219     // access its field since the field value is unknown after it.
2220     //
2221     Node* n = field->ideal_node();
2222     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2223       if (n->fast_out(i)->is_LoadStore()) {
2224         jobj->set_scalar_replaceable(false);
2225         return;
2226       }
2227     }
2228 
2229     // 5. Or the address may point to more then one object. This may produce
2230     // the false positive result (set not scalar replaceable)
2231     // since the flow-insensitive escape analysis can't separate
2232     // the case when stores overwrite the field's value from the case
2233     // when stores happened on different control branches.
2234     //
2235     // Note: it will disable scalar replacement in some cases:
2236     //
2237     //    Point p[] = new Point[1];
2238     //    p[0] = new Point(); // Will be not scalar replaced
2239     //
2240     // but it will save us from incorrect optimizations in next cases:
2241     //
2242     //    Point p[] = new Point[1];
2243     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
2244     //
2245     uint bcnt = field->base_count();
2246     if (bcnt > 1) {
2247       for (uint i = 0; i < bcnt; i++) {
2248         PointsToNode* base = field->base(i);
2249         // Don't take into account LocalVar nodes which
2250         // may point to only one object which should be also
2251         // this field's base by now.
2252         if (base->is_JavaObject() && base != jobj) {
2253           // Mark all bases.
2254           jobj->set_scalar_replaceable(false);
2255           base->set_scalar_replaceable(false);
2256         }
2257       }
2258     }
2259   }
2260 }
2261 
2262 
2263 // Propagate GlobalEscape and ArgEscape escape states to all nodes
2264 // and check that we still have non escaped java objects.
2265 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
2266                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
2267   GrowableArray<PointsToNode*> escape_worklist;
2268 
2269   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
2270   uint ptnodes_length = ptnodes_worklist.length();
2271   for (uint next = 0; next < ptnodes_length; ++next) {
2272     PointsToNode* ptn = ptnodes_worklist.at(next);
2273     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
2274         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
2275       escape_worklist.push(ptn);
2276     }
2277   }
2278   // Set escape states to referenced nodes (edges list).
2279   while (escape_worklist.length() > 0) {
2280     PointsToNode* ptn = escape_worklist.pop();
2281     PointsToNode::EscapeState es  = ptn->escape_state();
2282     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
2283     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
2284         es >= PointsToNode::ArgEscape) {
2285       // GlobalEscape or ArgEscape state of field means it has unknown value.
2286       if (add_edge(ptn, phantom_obj)) {
2287         // New edge was added
2288         add_field_uses_to_worklist(ptn->as_Field());
2289       }
2290     }
2291     uint cnt = ptn->edge_count();
2292     for (uint i = 0; i < cnt; i++) {
2293       PointsToNode* e = ptn->edge(i);
2294       if (e->is_Arraycopy()) {
2295         assert(ptn->arraycopy_dst(), "sanity");
2296         // Propagate only fields escape state through arraycopy edge.
2297         if (e->fields_escape_state() < field_es) {
2298           set_fields_escape_state(e, field_es);
2299           escape_worklist.push(e);
2300         }
2301       } else if (es >= field_es) {
2302         // fields_escape_state is also set to 'es' if it is less than 'es'.
2303         if (e->escape_state() < es) {
2304           set_escape_state(e, es);
2305           escape_worklist.push(e);
2306         }
2307       } else {
2308         // Propagate field escape state.
2309         bool es_changed = false;
2310         if (e->fields_escape_state() < field_es) {
2311           set_fields_escape_state(e, field_es);
2312           es_changed = true;
2313         }
2314         if ((e->escape_state() < field_es) &&
2315             e->is_Field() && ptn->is_JavaObject() &&
2316             e->as_Field()->is_oop()) {
2317           // Change escape state of referenced fileds.
2318           set_escape_state(e, field_es);
2319           es_changed = true;;
2320         } else if (e->escape_state() < es) {
2321           set_escape_state(e, es);
2322           es_changed = true;;
2323         }
2324         if (es_changed) {
2325           escape_worklist.push(e);
2326         }
2327       }
2328     }
2329   }
2330 
2331   // Remove escaped objects from non_escaped list.
2332   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
2333     JavaObjectNode* ptn = non_escaped_worklist.at(next);
2334     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
2335       non_escaped_worklist.delete_at(next);
2336     }
2337     if (ptn->escape_state() == PointsToNode::NoEscape) {
2338       // Find fields in non-escaped allocations which have unknown value.
2339       find_init_values(ptn, phantom_obj, NULL);
2340     }
2341   }
2342 
2343   return (non_escaped_worklist.length() > 0);
2344 }
2345 
2346 // Optimize objects compare.
2347 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
2348   assert(OptimizePtrCompare, "sanity");
2349 
2350   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
2351   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
2352   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
2353   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
2354 
2355   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
2356   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
2357 
2358   // Check simple cases first.
2359   if (jobj1 != NULL) {
2360     if (jobj1->escape_state() == PointsToNode::NoEscape) {
2361       if (jobj1 == jobj2) {
2362         // Comparing the same not escaping object.
2363         return _pcmp_eq;
2364       }
2365       Node* obj = jobj1->ideal_node();
2366       // Comparing not escaping allocation.
2367       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
2368           !ptn2->points_to(jobj1)) {
2369         return _pcmp_neq; // This includes nullness check.
2370       }
2371     }
2372   }
2373   if (jobj2 != NULL) {
2374     if (jobj2->escape_state() == PointsToNode::NoEscape) {
2375       Node* obj = jobj2->ideal_node();
2376       // Comparing not escaping allocation.
2377       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
2378           !ptn1->points_to(jobj2)) {
2379         return _pcmp_neq; // This includes nullness check.
2380       }
2381     }
2382   }
2383 
2384   if (jobj1 != NULL && jobj1 != phantom_obj &&
2385       jobj2 != NULL && jobj2 != phantom_obj &&
2386       jobj1->ideal_node()->is_Con() &&
2387       jobj2->ideal_node()->is_Con()) {
2388     // Klass or String constants compare. Need to be careful with
2389     // compressed pointers - compare types of ConN and ConP instead of nodes.
2390     const Type* t1 = jobj1->ideal_node()->bottom_type()->make_ptr();
2391     const Type* t2 = jobj2->ideal_node()->bottom_type()->make_ptr();
2392     assert(t1 != NULL && t2 != NULL, "sanity");
2393     if (t1->make_ptr() == t2->make_ptr()) {
2394       return _pcmp_eq;
2395     } else {
2396       return _pcmp_neq;
2397     }
2398   }
2399 
2400   if (ptn1->meet(ptn2)) {
2401     return NULL; // Sets are not disjoint
2402   }
2403 
2404   // Sets are disjoint.
2405   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
2406   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
2407   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
2408   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
2409 
2410   if (set1_has_unknown_ptr && set2_has_null_ptr ||
2411       set2_has_unknown_ptr && set1_has_null_ptr) {
2412     // Check nullness of unknown object.
2413     return NULL;
2414   }
2415 
2416   // Disjointness by itself is not sufficient since
2417   // alias analysis is not complete for escaped objects.
2418   // Disjoint sets are definitely unrelated only when
2419   // at least one set has only not escaping allocations.
2420   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
2421     if (ptn1->not_escaped_allocation()) {
2422       return _pcmp_neq;
2423     }
2424   }
2425   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
2426     if (ptn2->not_escaped_allocation()) {
2427       return _pcmp_neq;
2428     }
2429   }
2430   return NULL;
2431 }
2432 
2433 void ConnectionGraph::process_call_arguments(CallNode *call, PhaseTransform *phase) {
2434     bool is_arraycopy = false;
2435     switch (call->Opcode()) {
2436 #ifdef ASSERT
2437     case Op_Allocate:
2438     case Op_AllocateArray:
2439     case Op_Lock:
2440     case Op_Unlock:
2441       assert(false, "should be done already");
2442       break;
2443 #endif
2444     case Op_CallLeafNoFP:
2445       is_arraycopy = (call->as_CallLeaf()->_name != NULL &&
2446                       strstr(call->as_CallLeaf()->_name, "arraycopy") != 0);
2447       // fall through
2448     case Op_CallLeaf:
2449     {
2450       // Stub calls, objects do not escape but they are not scale replaceable.
2451       // Adjust escape state for outgoing arguments.
2452       const TypeTuple * d = call->tf()->domain();
2453       bool src_has_oops = false;
2454       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2455         const Type* at = d->field_at(i);
2456         Node *arg = call->in(i);
2457         const Type *aat = phase->type(arg);
2458         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
2459           continue;
2460         if (arg->is_AddP()) {
2461           //
2462           // The inline_native_clone() case when the arraycopy stub is called
2463           // after the allocation before Initialize and CheckCastPP nodes.
2464           // Or normal arraycopy for object arrays case.
2465           //
2466           // Set AddP's base (Allocate) as not scalar replaceable since
2467           // pointer to the base (with offset) is passed as argument.
2468           //
2469           arg = get_addp_base(arg);
2470         }
2471         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2472         assert(arg_ptn != NULL, "should be registered");
2473         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
2474         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
2475           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
2476                  aat->isa_ptr() != NULL, "expecting an Ptr");
2477           bool arg_has_oops = aat->isa_oopptr() &&
2478                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
2479                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
2480           if (i == TypeFunc::Parms) {
2481             src_has_oops = arg_has_oops;
2482           }
2483           //
2484           // src or dst could be j.l.Object when other is basic type array:
2485           //
2486           //   arraycopy(char[],0,Object*,0,size);
2487           //   arraycopy(Object*,0,char[],0,size);
2488           //
2489           // Don't add edges in such cases.
2490           //
2491           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
2492                                        arg_has_oops && (i > TypeFunc::Parms);
2493 #ifdef ASSERT
2494           if (!(is_arraycopy ||
2495                 call->as_CallLeaf()->_name != NULL &&
2496                 (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
2497                  strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ))
2498           ) {
2499             call->dump();
2500             assert(false, "EA: unexpected CallLeaf");
2501           }
2502 #endif
2503           // Always process arraycopy's destination object since
2504           // we need to add all possible edges to references in
2505           // source object.
2506           if (arg_esc >= PointsToNode::ArgEscape &&
2507               !arg_is_arraycopy_dest) {
2508             continue;
2509           }
2510           set_escape_state(arg_ptn, PointsToNode::ArgEscape);
2511           if (arg_is_arraycopy_dest) {
2512             Node* src = call->in(TypeFunc::Parms);
2513             if (src->is_AddP()) {
2514               src = get_addp_base(src);
2515             }
2516             PointsToNode* src_ptn = ptnode_adr(src->_idx);
2517             assert(src_ptn != NULL, "should be registered");
2518             if (arg_ptn != src_ptn) {
2519               // Special arraycopy edge:
2520               // A destination object's field can't have the source object
2521               // as base since objects escape states are not related.
2522               // Only escape state of destination object's fields affects
2523               // escape state of fields in source object.
2524               add_arraycopy(call, PointsToNode::ArgEscape, src_ptn, arg_ptn);
2525             }
2526           }
2527         }
2528       }
2529       break;
2530     }
2531 
2532     case Op_CallStaticJava:
2533     // For a static call, we know exactly what method is being called.
2534     // Use bytecode estimator to record the call's escape affects
2535     {
2536 #ifdef ASSERT
2537       const char* name = call->as_CallStaticJava()->_name;
2538       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
2539 #endif
2540 
2541       ciMethod* meth = call->as_CallJava()->method();
2542       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
2543       // fall-through if not a Java method or no analyzer information
2544       if (call_analyzer != NULL) {
2545         PointsToNode* call_ptn = ptnode_adr(call->_idx);
2546         const TypeTuple* d = call->tf()->domain();
2547         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2548           const Type* at = d->field_at(i);
2549           int k = i - TypeFunc::Parms;
2550           Node* arg = call->in(i);
2551           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2552           if (at->isa_ptr() != NULL &&
2553               call_analyzer->is_arg_returned(k)) {
2554             // The call returns arguments.
2555             if (call_ptn != NULL) { // Is call's result used?
2556               assert(call_ptn->is_LocalVar(), "node should be registered");
2557               assert(arg_ptn != NULL, "node should be registered");
2558               add_edge(call_ptn, arg_ptn);
2559             }
2560           }
2561           if (at->isa_oopptr() != NULL &&
2562               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
2563             bool global_escapes = false;
2564             bool fields_escapes = false;
2565             if (!call_analyzer->is_arg_stack(k)) {
2566               // The argument global escapes
2567               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
2568             } else {
2569               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
2570               if (!call_analyzer->is_arg_local(k)) {
2571                 // The argument itself doesn't escape, but any fields might
2572                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
2573               }
2574             }
2575           }
2576         }
2577         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
2578           // The call returns arguments.
2579           assert(call_ptn->edge_count() > 0, "sanity");
2580           if (!call_analyzer->is_return_local()) {
2581             // Returns also unknown object.
2582             add_edge(call_ptn, phantom_obj);
2583           }
2584         }
2585         break;
2586       }
2587     }
2588 
2589     default:
2590     // Fall-through here if not a Java method or no analyzer information
2591     // or some other type of call, assume the worst case: all arguments
2592     // globally escape.
2593     {
2594       const TypeTuple* d = call->tf()->domain();
2595       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2596         const Type* at = d->field_at(i);
2597         if (at->isa_oopptr() != NULL) {
2598           Node* arg = call->in(i);
2599           if (arg->is_AddP()) {
2600             arg = get_addp_base(arg);
2601           }
2602           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
2603           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
2604         }
2605       }
2606     }
2607   }
2608 }
2609 
2610 void ConnectionGraph::add_call_node(CallNode* call) {
2611   assert(call->returns_pointer(), "only for call which returns pointer");
2612   uint    call_idx = call->_idx;
2613   if (call->is_Allocate()) {
2614     Node* k = call->in(AllocateNode::KlassNode);
2615     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
2616     assert(kt != NULL, "TypeKlassPtr  required.");
2617     ciKlass* cik = kt->klass();
2618 
2619     PointsToNode::EscapeState es = PointsToNode::NoEscape;
2620     bool scalar_replaceable = true;
2621     if (call->is_AllocateArray()) {
2622       if (!cik->is_array_klass()) { // StressReflectiveCode
2623         es = PointsToNode::GlobalEscape;
2624       } else {
2625         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
2626         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
2627           // Not scalar replaceable if the length is not constant or too big.
2628           scalar_replaceable = false;
2629         }
2630       }
2631     } else {  // Allocate instance
2632       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
2633          !cik->is_instance_klass() || // StressReflectiveCode
2634           cik->as_instance_klass()->has_finalizer()) {
2635         es = PointsToNode::GlobalEscape;
2636       }
2637     }
2638     add_java_object(call, es);
2639     PointsToNode* ptn = ptnode_adr(call_idx);
2640     if (!scalar_replaceable && ptn->scalar_replaceable())
2641       ptn->set_scalar_replaceable(false);
2642 
2643   } else if (call->is_CallStaticJava()) {
2644     // Call nodes could be different types:
2645     //
2646     // 1. CallDynamicJavaNode (what happened during call is unknown):
2647     //
2648     //    - mapped to GlobalEscape JavaObject node if oop is returned;
2649     //
2650     //    - all oop arguments are escaping globally;
2651     //
2652     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
2653     //
2654     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
2655     //
2656     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
2657     //    - mapped to NoEscape JavaObject node if non escaped object allocated
2658     //      during call is returned;
2659     //    - mapped to ArgEscape LocalVar node pointed to object arguments
2660     //      which are returned and does not escape during call;
2661     //
2662     //    - oop arguments escaping status is defined by bytecode analysis;
2663     //
2664 
2665     // For a static call, we know exactly what method is being called.
2666     // Use bytecode estimator to record whether the call's return value escapes.
2667     ciMethod* meth = call->as_CallJava()->method();
2668     if (meth == NULL) {
2669       const char* name = call->as_CallStaticJava()->_name;
2670       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
2671       // Returns a newly allocated unescaped object.
2672       add_java_object(call, PointsToNode::NoEscape);
2673       ptnode_adr(call_idx)->set_scalar_replaceable(false);
2674     } else {
2675       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
2676       call_analyzer->copy_dependencies(_compile->dependencies());
2677       if (call_analyzer->is_return_allocated()) {
2678         // Returns a newly allocated unescaped object, simply
2679         // update dependency information.
2680         // Mark it as NoEscape so that objects referenced by
2681         // it's fields will be marked as NoEscape at least.
2682         add_java_object(call, PointsToNode::NoEscape);
2683         ptnode_adr(call_idx)->set_scalar_replaceable(false);
2684       } else {
2685         // Determine whether any arguments are returned.
2686         const TypeTuple* d = call->tf()->domain();
2687         bool ret_arg = false;
2688         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2689           if (d->field_at(i)->isa_ptr() != NULL &&
2690               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
2691             ret_arg = true;
2692             break;
2693           }
2694         }
2695         if (ret_arg) {
2696           add_local_var(call, PointsToNode::ArgEscape);
2697         } else {
2698           // Returns unknown object.
2699           map_ideal_node(call, phantom_obj);
2700         }
2701       }
2702     }
2703   } else {
2704     // An other type of call, assume the worst case:
2705     // returned value is unknown and globally escapes.
2706     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
2707     map_ideal_node(call, phantom_obj);
2708   }
2709 }
2710 
2711 // Populate Connection Graph with PointsTo nodes and create simple
2712 // connection graph edges.
2713 void ConnectionGraph::build_connection_graph(Node *n,
2714                                              Unique_Node_List *delayed_worklist,
2715                                              PhaseTransform *phase) {
2716   // During first iteration create PointsTo nodes and simple edges.
2717   // During second iteration create the rest of edges.
2718   bool first_iteration = (delayed_worklist != NULL);
2719 
2720   uint n_idx = n->_idx;
2721   PointsToNode* n_ptn = ptnode_adr(n_idx);
2722   if (first_iteration && n_ptn != NULL)
2723     return; // No need to redefine PointsTo node during first iteration.
2724 
2725 #ifdef ASSERT
2726   if (_verify && n_ptn->is_JavaObject())
2727     return; // Following code for JavaObject does not change graph.
2728 #endif
2729 
2730   if (n->is_Call()) {
2731     if (!first_iteration) {
2732       process_call_arguments(n->as_Call(), phase);
2733       return;
2734     }
2735     // Arguments to allocation and locking don't escape.
2736     if (n->is_AbstractLock()) {
2737       // Put Lock and Unlock nodes on IGVN worklist to process them during
2738       // first IGVN optimization when escape information is still available.
2739       record_for_optimizer(n);
2740     } else if (n->is_Allocate()) {
2741       add_call_node(n->as_Call());
2742       record_for_optimizer(n);
2743     } else {
2744       if (n->is_CallStaticJava()) {
2745         const char* name = n->as_CallStaticJava()->_name;
2746         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
2747           return; // Skip uncommon traps
2748       }
2749       // Don't mark as processed since call's arguments have to be processed.
2750       delayed_worklist->push(n);
2751 
2752       // Check if a call returns an object.
2753       if (n->as_Call()->returns_pointer() &&
2754           n->as_Call()->proj_out(TypeFunc::Parms) != NULL) {
2755         add_call_node(n->as_Call());
2756       }
2757     }
2758     return;
2759   }
2760 
2761   // Put this check here to process call arguments since some call nodes
2762   // point to phantom_obj.
2763   if (n_ptn == phantom_obj || n_ptn == null_obj)
2764     return; // Skip predefined nodes.
2765 
2766   assert(first_iteration || n->is_Store() || n->is_LoadStore() ||
2767          n_ptn != NULL && n_ptn->ideal_node() != NULL,
2768          "node should be registered during second iteration");
2769 
2770   int opcode = n->Opcode();
2771   switch (opcode) {
2772     case Op_AddP:
2773     {
2774       Node* base = get_addp_base(n);
2775       PointsToNode* ptn = ptnode_adr(base->_idx);
2776       if (first_iteration) {
2777         // Field node is created for all field types. It will help in
2778         // split_unique_types(). Note, there will be no uses of non oop fields
2779         // in Connection Graph.
2780         int offset = address_offset(n, phase);
2781         add_field(n, PointsToNode::NoEscape, offset);
2782         if (ptn == NULL) {
2783           delayed_worklist->push(n);
2784           return; // Process it later.
2785         }
2786         n_ptn = ptnode_adr(n_idx);
2787       } else {
2788         assert(ptn != NULL, "node should be registered");
2789       }
2790       add_base(n_ptn->as_Field(), ptn);
2791       break;
2792     }
2793     case Op_CastX2P:
2794     {
2795       if (first_iteration) {
2796         // "Unsafe" memory access to unknown object.
2797         map_ideal_node(n, phantom_obj);
2798       } else {
2799         assert(false, "Op_CastX2P");
2800       }
2801       break;
2802     }
2803     case Op_CastPP:
2804     case Op_CheckCastPP:
2805     case Op_EncodeP:
2806     case Op_DecodeN:
2807     {
2808       add_local_var_and_edge(n, PointsToNode::NoEscape,
2809                              n->in(1), delayed_worklist);
2810       break;
2811     }
2812     case Op_CMoveP:
2813     {
2814       if (first_iteration) {
2815         add_local_var(n, PointsToNode::NoEscape);
2816         // Do not add edges during first iteration because some could be
2817         // not defined yet.
2818         delayed_worklist->push(n);
2819         return; // Process it later.
2820       } else {
2821         for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
2822           Node* in = n->in(i);
2823           if (in == NULL)
2824             continue;  // ignore NULL
2825           Node* uncast_in = in->uncast();
2826           if (uncast_in->is_top() || uncast_in == n)
2827             continue;  // ignore top or inputs which go back this node
2828 
2829           PointsToNode* ptn = ptnode_adr(in->_idx);
2830           assert(ptn != NULL, "node should be registered");
2831           add_edge(n_ptn, ptn);
2832         }
2833       }
2834       break;
2835     }
2836     case Op_ConP:
2837     case Op_ConN:
2838     {
2839       // assume all oop constants globally escape except for null
2840       if (first_iteration) {
2841         PointsToNode::EscapeState es;
2842         if (phase->type(n) == TypePtr::NULL_PTR ||
2843             phase->type(n) == TypeNarrowOop::NULL_PTR) {
2844           es = PointsToNode::NoEscape;
2845         } else {
2846           es = PointsToNode::GlobalEscape;
2847         }
2848         add_java_object(n, es);
2849       } else {
2850         assert(false, "Op_ConP");
2851       }
2852       break;
2853     }
2854     case Op_CreateEx:
2855     {
2856       if (first_iteration) {
2857         // assume that all exception objects globally escape
2858         add_java_object(n, PointsToNode::GlobalEscape);
2859       } else {
2860         assert(false, "Op_CreateEx");
2861       }
2862       break;
2863     }
2864     case Op_LoadKlass:
2865     case Op_LoadNKlass:
2866     {
2867       if (first_iteration) {
2868         // Unknown class is loaded
2869         map_ideal_node(n, phantom_obj);
2870       } else {
2871         assert(false, "Op_LoadKlass");
2872       }
2873       break;
2874     }
2875     case Op_LoadP:
2876     case Op_LoadN:
2877     case Op_LoadPLocked:
2878     {
2879       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
2880       // ThreadLocal has RawPrt type.
2881       const Type* t = phase->type(n);
2882       if (t->make_ptr() != NULL) {
2883         Node* adr = n->in(MemNode::Address);
2884         if (!adr->is_AddP()) {
2885           assert(phase->type(adr)->isa_rawptr(), "sanity");
2886         } else {
2887           assert((ptnode_adr(adr->_idx) == NULL ||
2888                   ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
2889         }
2890         add_local_var_and_edge(n, PointsToNode::NoEscape,
2891                                adr, delayed_worklist);
2892 #ifdef ASSERT
2893       } else if (!first_iteration) {
2894         n->dump(1);
2895         assert(false, "Op_LoadP");
2896 #endif
2897       }
2898       break;
2899     }
2900     case Op_Parm:
2901     {
2902       if (first_iteration) {
2903         // We have to assume all input parameters globally escape
2904         map_ideal_node(n, phantom_obj);
2905       } else {
2906         assert(false, "Op_Parm");
2907       }
2908       break;
2909     }
2910     case Op_PartialSubtypeCheck:
2911     {
2912       if (first_iteration) {
2913         // Produces Null or notNull and is used in only in CmpP so
2914         // phantom_obj could be used.
2915         map_ideal_node(n, phantom_obj); // Result is unknown
2916       } else {
2917         // Arguments are klasses which globally escape so do not need
2918         // to point to them.
2919         assert(false, "Op_PartialSubtypeCheck");
2920       }
2921       break;
2922     }
2923     case Op_Phi:
2924     {
2925       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
2926       // ThreadLocal has RawPrt type.
2927       const Type* t = n->as_Phi()->type();
2928       if (t->make_ptr() != NULL) {
2929         if (first_iteration) {
2930           add_local_var(n, PointsToNode::NoEscape);
2931           // Do not add edges during first iteration because some could be
2932           // not defined yet.
2933           delayed_worklist->push(n);
2934           return; // Process it later.
2935         } else {
2936           for (uint i = 1; i < n->req(); i++) {
2937             Node* in = n->in(i);
2938             if (in == NULL)
2939               continue;  // ignore NULL
2940             Node* uncast_in = in->uncast();
2941             if (uncast_in->is_top() || uncast_in == n)
2942               continue;  // ignore top or inputs which go back this node
2943 
2944             PointsToNode* ptn = ptnode_adr(in->_idx);
2945             assert(ptn != NULL, "node should be registered");
2946             add_edge(n_ptn, ptn);
2947           }
2948         }
2949 #ifdef ASSERT
2950       } else if (!first_iteration) {
2951         n->dump(1);
2952         assert(false, "Op_Phi");
2953 #endif
2954       }
2955       break;
2956     }
2957     case Op_Proj:
2958     {
2959       // we are only interested in the oop result projection from a call
2960       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
2961           n->in(0)->as_Call()->returns_pointer()) {
2962         add_local_var_and_edge(n, PointsToNode::NoEscape,
2963                                n->in(0), delayed_worklist);
2964 #ifdef ASSERT
2965       } else if (!first_iteration) {
2966         n->dump(1);
2967         assert(false, "Op_Proj");
2968 #endif
2969       }
2970       break;
2971     }
2972     case Op_Rethrow: // Exception object escapes
2973     case Op_Return:
2974     {
2975       if (n->req() > TypeFunc::Parms &&
2976           phase->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
2977         // Treat Return value as LocalVar with GlobalEscape escape state.
2978         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
2979                                n->in(TypeFunc::Parms), delayed_worklist);
2980 #ifdef ASSERT
2981       } else if (!first_iteration) {
2982         assert(false, "Op_Return");
2983 #endif
2984       }
2985       break;
2986     }
2987     case Op_StoreP:
2988     case Op_StoreN:
2989     case Op_StorePConditional:
2990     case Op_CompareAndSwapP:
2991     case Op_CompareAndSwapN:
2992     {
2993       Node* adr = n->in(MemNode::Address);
2994       const Type *adr_type = phase->type(adr);
2995       adr_type = adr_type->make_ptr();
2996       if (adr_type->isa_oopptr() ||
2997           (opcode == Op_StoreP || opcode == Op_StoreN) &&
2998                         (adr_type == TypeRawPtr::NOTNULL &&
2999                          adr->in(AddPNode::Address)->is_Proj() &&
3000                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
3001 #ifdef ASSERT
3002         assert(adr->is_AddP(), "expecting an AddP");
3003         if (adr_type == TypeRawPtr::NOTNULL) {
3004           // Verify a raw address for a store captured by Initialize node.
3005           int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
3006           assert(offs != Type::OffsetBot, "offset must be a constant");
3007         }
3008 #endif
3009         if (first_iteration) {
3010           delayed_worklist->push(n);
3011           return; // Process it later.
3012         } else {
3013           // Point Address to Value
3014           PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
3015           assert(adr_ptn != NULL &&
3016                  adr_ptn->as_Field()->is_oop(), "node should be registered");
3017           Node *val = n->in(MemNode::ValueIn);
3018           PointsToNode* ptn = ptnode_adr(val->_idx);
3019           assert(ptn != NULL, "node should be registered");
3020           add_edge(adr_ptn, ptn);
3021         }
3022 #ifdef ASSERT
3023       } else {
3024         // Ignore copy the displaced header to the BoxNode (OSR compilation).
3025         if (adr->is_BoxLock())
3026           break;
3027 
3028         if (!adr->is_AddP()) {
3029           n->dump(1);
3030           assert(adr->is_AddP(), "expecting an AddP");
3031         }
3032         // Ignore G1 barrier's stores.
3033         if (!UseG1GC || (opcode != Op_StoreP) ||
3034             (adr_type != TypeRawPtr::BOTTOM)) {
3035           n->dump(1);
3036           assert(false, "not G1 barrier raw StoreP");
3037         }
3038 #endif
3039       }
3040       break;
3041     }
3042     case Op_AryEq:
3043     case Op_StrComp:
3044     case Op_StrEquals:
3045     case Op_StrIndexOf:
3046     {
3047       if (first_iteration) {
3048         add_local_var(n, PointsToNode::ArgEscape);
3049         delayed_worklist->push(n);
3050         return; // Process it later.
3051       } else {
3052         // char[] arrays passed to string intrinsic do not escape but
3053         // they are not scalar replaceable. Adjust escape state for them.
3054         // Start from in(2) edge since in(1) is memory edge.
3055         for (uint i = 2; i < n->req(); i++) {
3056           Node* adr = n->in(i);
3057           const Type* at = phase->type(adr);
3058           if (!adr->is_top() && at->isa_ptr()) {
3059             assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
3060                    at->isa_ptr() != NULL, "expecting a pointer");
3061             if (adr->is_AddP()) {
3062               adr = get_addp_base(adr);
3063             }
3064             PointsToNode* ptn = ptnode_adr(adr->_idx);
3065             assert(ptn != NULL, "node should be registered");
3066             add_edge(n_ptn, ptn);
3067           }
3068         }
3069       }
3070       break;
3071     }
3072     case Op_ThreadLocal:
3073     {
3074       if (first_iteration) {
3075         add_java_object(n, PointsToNode::ArgEscape);
3076       } else {
3077         assert(false, "Op_ThreadLocal");
3078       }
3079       break;
3080     }
3081     default:
3082       // During first iteration (when all ideal nodes are scanned) do nothing
3083       // for nodes not related to EA. During second iteration this method
3084       // should be called only for EA specific nodes.
3085       if (!first_iteration) {
3086         ShouldNotReachHere();
3087       }
3088   }
3089   return;
3090 }
3091 
3092 #ifndef PRODUCT
3093 static const char *node_type_names[] = {
3094   "UnknownType",
3095   "JavaObject",
3096   "LocalVar",
3097   "Field",
3098   "Arraycopy"
3099 };
3100 
3101 static const char *esc_names[] = {
3102   "UnknownEscape",
3103   "NoEscape",
3104   "ArgEscape",
3105   "GlobalEscape"
3106 };
3107 
3108 void PointsToNode::dump(bool print_state) const {
3109   NodeType nt = node_type();
3110   tty->print("%s ", node_type_names[(int) nt]);
3111   if (print_state) {
3112     EscapeState es = escape_state();
3113     EscapeState fields_es = fields_escape_state();
3114     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3115     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3116       tty->print("NSR");
3117   }
3118   if (is_Field()) {
3119     FieldNode* f = (FieldNode*)this;
3120     tty->print("(");
3121     for (uint i = 0; i < f->base_count(); i++) {
3122       PointsToNode* b = f->base(i);
3123       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3124     }
3125     tty->print(" )");
3126   }
3127   tty->print("[");
3128   for (uint i = 0; i < edge_count(); i++) {
3129     PointsToNode* e = edge(i);
3130     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3131   }
3132   tty->print(" [");
3133   for (uint i = 0; i < use_count(); i++) {
3134     PointsToNode* u = use(i);
3135     bool is_base = false;
3136     if (PointsToNode::is_base_use(u)) {
3137       is_base = true;
3138       u = PointsToNode::get_use_node(u)->as_Field();
3139     }
3140     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3141   }
3142   tty->print(" ]]  ");
3143   if (_node == NULL)
3144     tty->print_cr("<null>");
3145   else
3146     _node->dump();
3147 }
3148 
3149 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3150   bool first = true;
3151 
3152   uint ptnodes_length = ptnodes_worklist.length();
3153   for (uint i = 0; i < ptnodes_length; i++) {
3154     PointsToNode *ptn = ptnodes_worklist.at(i);
3155     if (ptn == NULL || !ptn->is_JavaObject())
3156       continue;
3157     PointsToNode::EscapeState es = ptn->escape_state();
3158     if (ptn->ideal_node()->is_Allocate() && (es == PointsToNode::NoEscape || Verbose)) {
3159       if (first) {
3160         tty->cr();
3161         tty->print("======== Connection graph for ");
3162         _compile->method()->print_short_name();
3163         tty->cr();
3164         first = false;
3165       }
3166       ptn->dump();
3167       // Print all locals and fields which reference this allocation
3168       uint count = ptn->use_count();
3169       for (uint i = 0; i < count; i++) {
3170         PointsToNode* use = ptn->use(i);
3171         if (use->is_LocalVar()) {
3172           use->dump(Verbose);
3173         } else if (Verbose) {
3174           use->dump();
3175         }
3176       }
3177       tty->cr();
3178     }
3179   }
3180 }
3181 #endif