1 /*
   2  * Copyright 2005-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 #include "incls/_precompiled.incl"
  26 #include "incls/_escape.cpp.incl"
  27 
  28 uint PointsToNode::edge_target(uint e) const {
  29   assert(_edges != NULL && e < (uint)_edges->length(), "valid edge index");
  30   return (_edges->at(e) >> EdgeShift);
  31 }
  32 
  33 PointsToNode::EdgeType PointsToNode::edge_type(uint e) const {
  34   assert(_edges != NULL && e < (uint)_edges->length(), "valid edge index");
  35   return (EdgeType) (_edges->at(e) & EdgeMask);
  36 }
  37 
  38 void PointsToNode::add_edge(uint targIdx, PointsToNode::EdgeType et) {
  39   uint v = (targIdx << EdgeShift) + ((uint) et);
  40   if (_edges == NULL) {
  41      Arena *a = Compile::current()->comp_arena();
  42     _edges = new(a) GrowableArray<uint>(a, INITIAL_EDGE_COUNT, 0, 0);
  43   }
  44   _edges->append_if_missing(v);
  45 }
  46 
  47 void PointsToNode::remove_edge(uint targIdx, PointsToNode::EdgeType et) {
  48   uint v = (targIdx << EdgeShift) + ((uint) et);
  49 
  50   _edges->remove(v);
  51 }
  52 
  53 #ifndef PRODUCT
  54 static const char *node_type_names[] = {
  55   "UnknownType",
  56   "JavaObject",
  57   "LocalVar",
  58   "Field"
  59 };
  60 
  61 static const char *esc_names[] = {
  62   "UnknownEscape",
  63   "NoEscape",
  64   "ArgEscape",
  65   "GlobalEscape"
  66 };
  67 
  68 static const char *edge_type_suffix[] = {
  69  "?", // UnknownEdge
  70  "P", // PointsToEdge
  71  "D", // DeferredEdge
  72  "F"  // FieldEdge
  73 };
  74 
  75 void PointsToNode::dump() const {
  76   NodeType nt = node_type();
  77   EscapeState es = escape_state();
  78   tty->print("%s %s %s [[", node_type_names[(int) nt], esc_names[(int) es], _scalar_replaceable ? "" : "NSR");
  79   for (uint i = 0; i < edge_count(); i++) {
  80     tty->print(" %d%s", edge_target(i), edge_type_suffix[(int) edge_type(i)]);
  81   }
  82   tty->print("]]  ");
  83   if (_node == NULL)
  84     tty->print_cr("<null>");
  85   else
  86     _node->dump();
  87 }
  88 #endif
  89 
  90 ConnectionGraph::ConnectionGraph(Compile * C) : _processed(C->comp_arena()), _node_map(C->comp_arena()) {
  91   _collecting = true;
  92   this->_compile = C;
  93   const PointsToNode &dummy = PointsToNode();
  94   int sz = C->unique();
  95   _nodes = new(C->comp_arena()) GrowableArray<PointsToNode>(C->comp_arena(), sz, sz, dummy);
  96   _phantom_object = C->top()->_idx;
  97   PointsToNode *phn = ptnode_adr(_phantom_object);
  98   phn->_node = C->top();
  99   phn->set_node_type(PointsToNode::JavaObject);
 100   phn->set_escape_state(PointsToNode::GlobalEscape);
 101 }
 102 
 103 void ConnectionGraph::add_pointsto_edge(uint from_i, uint to_i) {
 104   PointsToNode *f = ptnode_adr(from_i);
 105   PointsToNode *t = ptnode_adr(to_i);
 106 
 107   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");
 108   assert(f->node_type() == PointsToNode::LocalVar || f->node_type() == PointsToNode::Field, "invalid source of PointsTo edge");
 109   assert(t->node_type() == PointsToNode::JavaObject, "invalid destination of PointsTo edge");
 110   f->add_edge(to_i, PointsToNode::PointsToEdge);
 111 }
 112 
 113 void ConnectionGraph::add_deferred_edge(uint from_i, uint to_i) {
 114   PointsToNode *f = ptnode_adr(from_i);
 115   PointsToNode *t = ptnode_adr(to_i);
 116 
 117   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");
 118   assert(f->node_type() == PointsToNode::LocalVar || f->node_type() == PointsToNode::Field, "invalid source of Deferred edge");
 119   assert(t->node_type() == PointsToNode::LocalVar || t->node_type() == PointsToNode::Field, "invalid destination of Deferred edge");
 120   // don't add a self-referential edge, this can occur during removal of
 121   // deferred edges
 122   if (from_i != to_i)
 123     f->add_edge(to_i, PointsToNode::DeferredEdge);
 124 }
 125 
 126 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
 127   const Type *adr_type = phase->type(adr);
 128   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
 129       adr->in(AddPNode::Address)->is_Proj() &&
 130       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
 131     // We are computing a raw address for a store captured by an Initialize
 132     // compute an appropriate address type. AddP cases #3 and #5 (see below).
 133     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 134     assert(offs != Type::OffsetBot ||
 135            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
 136            "offset must be a constant or it is initialization of array");
 137     return offs;
 138   }
 139   const TypePtr *t_ptr = adr_type->isa_ptr();
 140   assert(t_ptr != NULL, "must be a pointer type");
 141   return t_ptr->offset();
 142 }
 143 
 144 void ConnectionGraph::add_field_edge(uint from_i, uint to_i, int offset) {
 145   PointsToNode *f = ptnode_adr(from_i);
 146   PointsToNode *t = ptnode_adr(to_i);
 147 
 148   assert(f->node_type() != PointsToNode::UnknownType && t->node_type() != PointsToNode::UnknownType, "node types must be set");
 149   assert(f->node_type() == PointsToNode::JavaObject, "invalid destination of Field edge");
 150   assert(t->node_type() == PointsToNode::Field, "invalid destination of Field edge");
 151   assert (t->offset() == -1 || t->offset() == offset, "conflicting field offsets");
 152   t->set_offset(offset);
 153 
 154   f->add_edge(to_i, PointsToNode::FieldEdge);
 155 }
 156 
 157 void ConnectionGraph::set_escape_state(uint ni, PointsToNode::EscapeState es) {
 158   PointsToNode *npt = ptnode_adr(ni);
 159   PointsToNode::EscapeState old_es = npt->escape_state();
 160   if (es > old_es)
 161     npt->set_escape_state(es);
 162 }
 163 
 164 void ConnectionGraph::add_node(Node *n, PointsToNode::NodeType nt,
 165                                PointsToNode::EscapeState es, bool done) {
 166   PointsToNode* ptadr = ptnode_adr(n->_idx);
 167   ptadr->_node = n;
 168   ptadr->set_node_type(nt);
 169 
 170   // inline set_escape_state(idx, es);
 171   PointsToNode::EscapeState old_es = ptadr->escape_state();
 172   if (es > old_es)
 173     ptadr->set_escape_state(es);
 174 
 175   if (done)
 176     _processed.set(n->_idx);
 177 }
 178 
 179 PointsToNode::EscapeState ConnectionGraph::escape_state(Node *n, PhaseTransform *phase) {
 180   uint idx = n->_idx;
 181   PointsToNode::EscapeState es;
 182 
 183   // If we are still collecting or there were no non-escaping allocations
 184   // we don't know the answer yet
 185   if (_collecting || !_has_allocations)
 186     return PointsToNode::UnknownEscape;
 187 
 188   // if the node was created after the escape computation, return
 189   // UnknownEscape
 190   if (idx >= (uint)_nodes->length())
 191     return PointsToNode::UnknownEscape;
 192 
 193   es = _nodes->at_grow(idx).escape_state();
 194 
 195   // if we have already computed a value, return it
 196   if (es != PointsToNode::UnknownEscape)
 197     return es;
 198 
 199   // compute max escape state of anything this node could point to
 200   VectorSet ptset(Thread::current()->resource_area());
 201   PointsTo(ptset, n, phase);
 202   for(VectorSetI i(&ptset); i.test() && es != PointsToNode::GlobalEscape; ++i) {
 203     uint pt = i.elem;
 204     PointsToNode::EscapeState pes = _nodes->adr_at(pt)->escape_state();
 205     if (pes > es)
 206       es = pes;
 207   }
 208   // cache the computed escape state
 209   assert(es != PointsToNode::UnknownEscape, "should have computed an escape state");
 210   _nodes->adr_at(idx)->set_escape_state(es);
 211   return es;
 212 }
 213 
 214 void ConnectionGraph::PointsTo(VectorSet &ptset, Node * n, PhaseTransform *phase) {
 215   VectorSet visited(Thread::current()->resource_area());
 216   GrowableArray<uint>  worklist;
 217 
 218 #ifdef ASSERT
 219   Node *orig_n = n;
 220 #endif
 221 
 222   n = n->uncast();
 223   PointsToNode  npt = _nodes->at_grow(n->_idx);
 224 
 225   // If we have a JavaObject, return just that object
 226   if (npt.node_type() == PointsToNode::JavaObject) {
 227     ptset.set(n->_idx);
 228     return;
 229   }
 230 #ifdef ASSERT
 231   if (npt._node == NULL) {
 232     if (orig_n != n)
 233       orig_n->dump();
 234     n->dump();
 235     assert(npt._node != NULL, "unregistered node");
 236   }
 237 #endif
 238   worklist.push(n->_idx);
 239   while(worklist.length() > 0) {
 240     int ni = worklist.pop();
 241     PointsToNode pn = _nodes->at_grow(ni);
 242     if (!visited.test_set(ni)) {
 243       // ensure that all inputs of a Phi have been processed
 244       assert(!_collecting || !pn._node->is_Phi() || _processed.test(ni),"");
 245 
 246       int edges_processed = 0;
 247       for (uint e = 0; e < pn.edge_count(); e++) {
 248         uint etgt = pn.edge_target(e);
 249         PointsToNode::EdgeType et = pn.edge_type(e);
 250         if (et == PointsToNode::PointsToEdge) {
 251           ptset.set(etgt);
 252           edges_processed++;
 253         } else if (et == PointsToNode::DeferredEdge) {
 254           worklist.push(etgt);
 255           edges_processed++;
 256         } else {
 257           assert(false,"neither PointsToEdge or DeferredEdge");
 258         }
 259       }
 260       if (edges_processed == 0) {
 261         // no deferred or pointsto edges found.  Assume the value was set
 262         // outside this method.  Add the phantom object to the pointsto set.
 263         ptset.set(_phantom_object);
 264       }
 265     }
 266   }
 267 }
 268 
 269 void ConnectionGraph::remove_deferred(uint ni, GrowableArray<uint>* deferred_edges, VectorSet* visited) {
 270   // This method is most expensive during ConnectionGraph construction.
 271   // Reuse vectorSet and an additional growable array for deferred edges.
 272   deferred_edges->clear();
 273   visited->Clear();
 274 
 275   uint i = 0;
 276   PointsToNode *ptn = ptnode_adr(ni);
 277 
 278   // Mark current edges as visited and move deferred edges to separate array.
 279   while (i < ptn->edge_count()) {
 280     uint t = ptn->edge_target(i);
 281 #ifdef ASSERT
 282     assert(!visited->test_set(t), "expecting no duplications");
 283 #else
 284     visited->set(t);
 285 #endif
 286     if (ptn->edge_type(i) == PointsToNode::DeferredEdge) {
 287       ptn->remove_edge(t, PointsToNode::DeferredEdge);
 288       deferred_edges->append(t);
 289     } else {
 290       i++;
 291     }
 292   }
 293   for (int next = 0; next < deferred_edges->length(); ++next) {
 294     uint t = deferred_edges->at(next);
 295     PointsToNode *ptt = ptnode_adr(t);
 296     for (uint j = 0; j < ptt->edge_count(); j++) {
 297       uint n1 = ptt->edge_target(j);
 298       if (visited->test_set(n1))
 299         continue;
 300       switch(ptt->edge_type(j)) {
 301         case PointsToNode::PointsToEdge:
 302           add_pointsto_edge(ni, n1);
 303           if(n1 == _phantom_object) {
 304             // Special case - field set outside (globally escaping).
 305             ptn->set_escape_state(PointsToNode::GlobalEscape);
 306           }
 307           break;
 308         case PointsToNode::DeferredEdge:
 309           deferred_edges->append(n1);
 310           break;
 311         case PointsToNode::FieldEdge:
 312           assert(false, "invalid connection graph");
 313           break;
 314       }
 315     }
 316   }
 317 }
 318 
 319 
 320 //  Add an edge to node given by "to_i" from any field of adr_i whose offset
 321 //  matches "offset"  A deferred edge is added if to_i is a LocalVar, and
 322 //  a pointsto edge is added if it is a JavaObject
 323 
 324 void ConnectionGraph::add_edge_from_fields(uint adr_i, uint to_i, int offs) {
 325   PointsToNode an = _nodes->at_grow(adr_i);
 326   PointsToNode to = _nodes->at_grow(to_i);
 327   bool deferred = (to.node_type() == PointsToNode::LocalVar);
 328 
 329   for (uint fe = 0; fe < an.edge_count(); fe++) {
 330     assert(an.edge_type(fe) == PointsToNode::FieldEdge, "expecting a field edge");
 331     int fi = an.edge_target(fe);
 332     PointsToNode pf = _nodes->at_grow(fi);
 333     int po = pf.offset();
 334     if (po == offs || po == Type::OffsetBot || offs == Type::OffsetBot) {
 335       if (deferred)
 336         add_deferred_edge(fi, to_i);
 337       else
 338         add_pointsto_edge(fi, to_i);
 339     }
 340   }
 341 }
 342 
 343 // Add a deferred  edge from node given by "from_i" to any field of adr_i
 344 // whose offset matches "offset".
 345 void ConnectionGraph::add_deferred_edge_to_fields(uint from_i, uint adr_i, int offs) {
 346   PointsToNode an = _nodes->at_grow(adr_i);
 347   for (uint fe = 0; fe < an.edge_count(); fe++) {
 348     assert(an.edge_type(fe) == PointsToNode::FieldEdge, "expecting a field edge");
 349     int fi = an.edge_target(fe);
 350     PointsToNode pf = _nodes->at_grow(fi);
 351     int po = pf.offset();
 352     if (pf.edge_count() == 0) {
 353       // we have not seen any stores to this field, assume it was set outside this method
 354       add_pointsto_edge(fi, _phantom_object);
 355     }
 356     if (po == offs || po == Type::OffsetBot || offs == Type::OffsetBot) {
 357       add_deferred_edge(from_i, fi);
 358     }
 359   }
 360 }
 361 
 362 // Helper functions
 363 
 364 static Node* get_addp_base(Node *addp) {
 365   assert(addp->is_AddP(), "must be AddP");
 366   //
 367   // AddP cases for Base and Address inputs:
 368   // case #1. Direct object's field reference:
 369   //     Allocate
 370   //       |
 371   //     Proj #5 ( oop result )
 372   //       |
 373   //     CheckCastPP (cast to instance type)
 374   //      | |
 375   //     AddP  ( base == address )
 376   //
 377   // case #2. Indirect object's field reference:
 378   //      Phi
 379   //       |
 380   //     CastPP (cast to instance type)
 381   //      | |
 382   //     AddP  ( base == address )
 383   //
 384   // case #3. Raw object's field reference for Initialize node:
 385   //      Allocate
 386   //        |
 387   //      Proj #5 ( oop result )
 388   //  top   |
 389   //     \  |
 390   //     AddP  ( base == top )
 391   //
 392   // case #4. Array's element reference:
 393   //   {CheckCastPP | CastPP}
 394   //     |  | |
 395   //     |  AddP ( array's element offset )
 396   //     |  |
 397   //     AddP ( array's offset )
 398   //
 399   // case #5. Raw object's field reference for arraycopy stub call:
 400   //          The inline_native_clone() case when the arraycopy stub is called
 401   //          after the allocation before Initialize and CheckCastPP nodes.
 402   //      Allocate
 403   //        |
 404   //      Proj #5 ( oop result )
 405   //       | |
 406   //       AddP  ( base == address )
 407   //
 408   // case #6. Constant Pool, ThreadLocal, CastX2P or
 409   //          Raw object's field reference:
 410   //      {ConP, ThreadLocal, CastX2P, raw Load}
 411   //  top   |
 412   //     \  |
 413   //     AddP  ( base == top )
 414   //
 415   // case #7. Klass's field reference.
 416   //      LoadKlass
 417   //       | |
 418   //       AddP  ( base == address )
 419   //
 420   // case #8. narrow Klass's field reference.
 421   //      LoadNKlass
 422   //       |
 423   //      DecodeN
 424   //       | |
 425   //       AddP  ( base == address )
 426   //
 427   Node *base = addp->in(AddPNode::Base)->uncast();
 428   if (base->is_top()) { // The AddP case #3 and #6.
 429     base = addp->in(AddPNode::Address)->uncast();
 430     assert(base->Opcode() == Op_ConP || base->Opcode() == Op_ThreadLocal ||
 431            base->Opcode() == Op_CastX2P || base->is_DecodeN() ||
 432            (base->is_Mem() && base->bottom_type() == TypeRawPtr::NOTNULL) ||
 433            (base->is_Proj() && base->in(0)->is_Allocate()), "sanity");
 434   }
 435   return base;
 436 }
 437 
 438 static Node* find_second_addp(Node* addp, Node* n) {
 439   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
 440 
 441   Node* addp2 = addp->raw_out(0);
 442   if (addp->outcnt() == 1 && addp2->is_AddP() &&
 443       addp2->in(AddPNode::Base) == n &&
 444       addp2->in(AddPNode::Address) == addp) {
 445 
 446     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
 447     //
 448     // Find array's offset to push it on worklist first and
 449     // as result process an array's element offset first (pushed second)
 450     // to avoid CastPP for the array's offset.
 451     // Otherwise the inserted CastPP (LocalVar) will point to what
 452     // the AddP (Field) points to. Which would be wrong since
 453     // the algorithm expects the CastPP has the same point as
 454     // as AddP's base CheckCastPP (LocalVar).
 455     //
 456     //    ArrayAllocation
 457     //     |
 458     //    CheckCastPP
 459     //     |
 460     //    memProj (from ArrayAllocation CheckCastPP)
 461     //     |  ||
 462     //     |  ||   Int (element index)
 463     //     |  ||    |   ConI (log(element size))
 464     //     |  ||    |   /
 465     //     |  ||   LShift
 466     //     |  ||  /
 467     //     |  AddP (array's element offset)
 468     //     |  |
 469     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
 470     //     | / /
 471     //     AddP (array's offset)
 472     //      |
 473     //     Load/Store (memory operation on array's element)
 474     //
 475     return addp2;
 476   }
 477   return NULL;
 478 }
 479 
 480 //
 481 // Adjust the type and inputs of an AddP which computes the
 482 // address of a field of an instance
 483 //
 484 void ConnectionGraph::split_AddP(Node *addp, Node *base,  PhaseGVN  *igvn) {
 485   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
 486   assert(base_t != NULL && base_t->is_instance(), "expecting instance oopptr");
 487   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
 488   if (t == NULL) {
 489     // We are computing a raw address for a store captured by an Initialize
 490     // compute an appropriate address type.
 491     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
 492     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
 493     int offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
 494     assert(offs != Type::OffsetBot, "offset must be a constant");
 495     t = base_t->add_offset(offs)->is_oopptr();
 496   }
 497   uint inst_id =  base_t->instance_id();
 498   assert(!t->is_instance() || t->instance_id() == inst_id,
 499                              "old type must be non-instance or match new type");
 500   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
 501   // Do NOT remove the next call: ensure an new alias index is allocated
 502   // for the instance type
 503   int alias_idx = _compile->get_alias_index(tinst);
 504   igvn->set_type(addp, tinst);
 505   // record the allocation in the node map
 506   set_map(addp->_idx, get_map(base->_idx));
 507   // if the Address input is not the appropriate instance type
 508   // (due to intervening casts,) insert a cast
 509   Node *adr = addp->in(AddPNode::Address);
 510   const TypeOopPtr  *atype = igvn->type(adr)->isa_oopptr();
 511   if (atype != NULL && atype->instance_id() != inst_id) {
 512     assert(!atype->is_instance(), "no conflicting instances");
 513     const TypeOopPtr *new_atype = base_t->add_offset(atype->offset())->isa_oopptr();
 514     Node *acast = new (_compile, 2) CastPPNode(adr, new_atype);
 515     acast->set_req(0, adr->in(0));
 516     igvn->set_type(acast, new_atype);
 517     record_for_optimizer(acast);
 518     Node *bcast = acast;
 519     Node *abase = addp->in(AddPNode::Base);
 520     if (abase != adr) {
 521       bcast = new (_compile, 2) CastPPNode(abase, base_t);
 522       bcast->set_req(0, abase->in(0));
 523       igvn->set_type(bcast, base_t);
 524       record_for_optimizer(bcast);
 525     }
 526     igvn->hash_delete(addp);
 527     addp->set_req(AddPNode::Base, bcast);
 528     addp->set_req(AddPNode::Address, acast);
 529     igvn->hash_insert(addp);
 530   }
 531   // Put on IGVN worklist since at least addp's type was changed above.
 532   record_for_optimizer(addp);
 533 }
 534 
 535 //
 536 // Create a new version of orig_phi if necessary. Returns either the newly
 537 // created phi or an existing phi.  Sets create_new to indicate wheter  a new
 538 // phi was created.  Cache the last newly created phi in the node map.
 539 //
 540 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn, bool &new_created) {
 541   Compile *C = _compile;
 542   new_created = false;
 543   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
 544   // nothing to do if orig_phi is bottom memory or matches alias_idx
 545   if (phi_alias_idx == alias_idx) {
 546     return orig_phi;
 547   }
 548   // have we already created a Phi for this alias index?
 549   PhiNode *result = get_map_phi(orig_phi->_idx);
 550   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
 551     return result;
 552   }
 553   if ((int)C->unique() + 2*NodeLimitFudgeFactor > MaxNodeLimit) {
 554     if (C->do_escape_analysis() == true && !C->failing()) {
 555       // Retry compilation without escape analysis.
 556       // If this is the first failure, the sentinel string will "stick"
 557       // to the Compile object, and the C2Compiler will see it and retry.
 558       C->record_failure(C2Compiler::retry_no_escape_analysis());
 559     }
 560     return NULL;
 561   }
 562   orig_phi_worklist.append_if_missing(orig_phi);
 563   const TypePtr *atype = C->get_adr_type(alias_idx);
 564   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
 565   set_map_phi(orig_phi->_idx, result);
 566   igvn->set_type(result, result->bottom_type());
 567   record_for_optimizer(result);
 568   new_created = true;
 569   return result;
 570 }
 571 
 572 //
 573 // Return a new version  of Memory Phi "orig_phi" with the inputs having the
 574 // specified alias index.
 575 //
 576 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, PhaseGVN  *igvn) {
 577 
 578   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
 579   Compile *C = _compile;
 580   bool new_phi_created;
 581   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, igvn, new_phi_created);
 582   if (!new_phi_created) {
 583     return result;
 584   }
 585 
 586   GrowableArray<PhiNode *>  phi_list;
 587   GrowableArray<uint>  cur_input;
 588 
 589   PhiNode *phi = orig_phi;
 590   uint idx = 1;
 591   bool finished = false;
 592   while(!finished) {
 593     while (idx < phi->req()) {
 594       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, igvn);
 595       if (mem != NULL && mem->is_Phi()) {
 596         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, igvn, new_phi_created);
 597         if (new_phi_created) {
 598           // found an phi for which we created a new split, push current one on worklist and begin
 599           // processing new one
 600           phi_list.push(phi);
 601           cur_input.push(idx);
 602           phi = mem->as_Phi();
 603           result = newphi;
 604           idx = 1;
 605           continue;
 606         } else {
 607           mem = newphi;
 608         }
 609       }
 610       if (C->failing()) {
 611         return NULL;
 612       }
 613       result->set_req(idx++, mem);
 614     }
 615 #ifdef ASSERT
 616     // verify that the new Phi has an input for each input of the original
 617     assert( phi->req() == result->req(), "must have same number of inputs.");
 618     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
 619 #endif
 620     // Check if all new phi's inputs have specified alias index.
 621     // Otherwise use old phi.
 622     for (uint i = 1; i < phi->req(); i++) {
 623       Node* in = result->in(i);
 624       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
 625     }
 626     // we have finished processing a Phi, see if there are any more to do
 627     finished = (phi_list.length() == 0 );
 628     if (!finished) {
 629       phi = phi_list.pop();
 630       idx = cur_input.pop();
 631       PhiNode *prev_result = get_map_phi(phi->_idx);
 632       prev_result->set_req(idx++, result);
 633       result = prev_result;
 634     }
 635   }
 636   return result;
 637 }
 638 
 639 
 640 //
 641 // The next methods are derived from methods in MemNode.
 642 //
 643 static Node *step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *tinst) {
 644   Node *mem = mmem;
 645   // TypeInstPtr::NOTNULL+any is an OOP with unknown offset - generally
 646   // means an array I have not precisely typed yet.  Do not do any
 647   // alias stuff with it any time soon.
 648   if( tinst->base() != Type::AnyPtr &&
 649       !(tinst->klass()->is_java_lang_Object() &&
 650         tinst->offset() == Type::OffsetBot) ) {
 651     mem = mmem->memory_at(alias_idx);
 652     // Update input if it is progress over what we have now
 653   }
 654   return mem;
 655 }
 656 
 657 //
 658 // Search memory chain of "mem" to find a MemNode whose address
 659 // is the specified alias index.
 660 //
 661 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, PhaseGVN *phase) {
 662   if (orig_mem == NULL)
 663     return orig_mem;
 664   Compile* C = phase->C;
 665   const TypeOopPtr *tinst = C->get_adr_type(alias_idx)->isa_oopptr();
 666   bool is_instance = (tinst != NULL) && tinst->is_instance();
 667   Node *prev = NULL;
 668   Node *result = orig_mem;
 669   while (prev != result) {
 670     prev = result;
 671     if (result->is_Mem()) {
 672       MemNode *mem = result->as_Mem();
 673       const Type *at = phase->type(mem->in(MemNode::Address));
 674       if (at != Type::TOP) {
 675         assert (at->isa_ptr() != NULL, "pointer type required.");
 676         int idx = C->get_alias_index(at->is_ptr());
 677         if (idx == alias_idx)
 678           break;
 679       }
 680       result = mem->in(MemNode::Memory);
 681     }
 682     if (!is_instance)
 683       continue;  // don't search further for non-instance types
 684     // skip over a call which does not affect this memory slice
 685     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
 686       Node *proj_in = result->in(0);
 687       if (proj_in->is_Call()) {
 688         CallNode *call = proj_in->as_Call();
 689         if (!call->may_modify(tinst, phase)) {
 690           result = call->in(TypeFunc::Memory);
 691         }
 692       } else if (proj_in->is_Initialize()) {
 693         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
 694         // Stop if this is the initialization for the object instance which
 695         // which contains this memory slice, otherwise skip over it.
 696         if (alloc == NULL || alloc->_idx != tinst->instance_id()) {
 697           result = proj_in->in(TypeFunc::Memory);
 698         }
 699       } else if (proj_in->is_MemBar()) {
 700         result = proj_in->in(TypeFunc::Memory);
 701       }
 702     } else if (result->is_MergeMem()) {
 703       MergeMemNode *mmem = result->as_MergeMem();
 704       result = step_through_mergemem(mmem, alias_idx, tinst);
 705       if (result == mmem->base_memory()) {
 706         // Didn't find instance memory, search through general slice recursively.
 707         result = mmem->memory_at(C->get_general_index(alias_idx));
 708         result = find_inst_mem(result, alias_idx, orig_phis, phase);
 709         if (C->failing()) {
 710           return NULL;
 711         }
 712         mmem->set_memory_at(alias_idx, result);
 713       }
 714     } else if (result->is_Phi() &&
 715                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
 716       Node *un = result->as_Phi()->unique_input(phase);
 717       if (un != NULL) {
 718         result = un;
 719       } else {
 720         break;
 721       }
 722     }
 723   }
 724   if (is_instance && result->is_Phi()) {
 725     PhiNode *mphi = result->as_Phi();
 726     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
 727     const TypePtr *t = mphi->adr_type();
 728     if (C->get_alias_index(t) != alias_idx) {
 729       result = split_memory_phi(mphi, alias_idx, orig_phis, phase);
 730     }
 731   }
 732   // the result is either MemNode, PhiNode, InitializeNode.
 733   return result;
 734 }
 735 
 736 
 737 //
 738 //  Convert the types of unescaped object to instance types where possible,
 739 //  propagate the new type information through the graph, and update memory
 740 //  edges and MergeMem inputs to reflect the new type.
 741 //
 742 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
 743 //  The processing is done in 4 phases:
 744 //
 745 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
 746 //            types for the CheckCastPP for allocations where possible.
 747 //            Propagate the the new types through users as follows:
 748 //               casts and Phi:  push users on alloc_worklist
 749 //               AddP:  cast Base and Address inputs to the instance type
 750 //                      push any AddP users on alloc_worklist and push any memnode
 751 //                      users onto memnode_worklist.
 752 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
 753 //            search the Memory chain for a store with the appropriate type
 754 //            address type.  If a Phi is found, create a new version with
 755 //            the approriate memory slices from each of the Phi inputs.
 756 //            For stores, process the users as follows:
 757 //               MemNode:  push on memnode_worklist
 758 //               MergeMem: push on mergemem_worklist
 759 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
 760 //            moving the first node encountered of each  instance type to the
 761 //            the input corresponding to its alias index.
 762 //            appropriate memory slice.
 763 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
 764 //
 765 // In the following example, the CheckCastPP nodes are the cast of allocation
 766 // results and the allocation of node 29 is unescaped and eligible to be an
 767 // instance type.
 768 //
 769 // We start with:
 770 //
 771 //     7 Parm #memory
 772 //    10  ConI  "12"
 773 //    19  CheckCastPP   "Foo"
 774 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
 775 //    29  CheckCastPP   "Foo"
 776 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
 777 //
 778 //    40  StoreP  25   7  20   ... alias_index=4
 779 //    50  StoreP  35  40  30   ... alias_index=4
 780 //    60  StoreP  45  50  20   ... alias_index=4
 781 //    70  LoadP    _  60  30   ... alias_index=4
 782 //    80  Phi     75  50  60   Memory alias_index=4
 783 //    90  LoadP    _  80  30   ... alias_index=4
 784 //   100  LoadP    _  80  20   ... alias_index=4
 785 //
 786 //
 787 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
 788 // and creating a new alias index for node 30.  This gives:
 789 //
 790 //     7 Parm #memory
 791 //    10  ConI  "12"
 792 //    19  CheckCastPP   "Foo"
 793 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
 794 //    29  CheckCastPP   "Foo"  iid=24
 795 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
 796 //
 797 //    40  StoreP  25   7  20   ... alias_index=4
 798 //    50  StoreP  35  40  30   ... alias_index=6
 799 //    60  StoreP  45  50  20   ... alias_index=4
 800 //    70  LoadP    _  60  30   ... alias_index=6
 801 //    80  Phi     75  50  60   Memory alias_index=4
 802 //    90  LoadP    _  80  30   ... alias_index=6
 803 //   100  LoadP    _  80  20   ... alias_index=4
 804 //
 805 // In phase 2, new memory inputs are computed for the loads and stores,
 806 // And a new version of the phi is created.  In phase 4, the inputs to
 807 // node 80 are updated and then the memory nodes are updated with the
 808 // values computed in phase 2.  This results in:
 809 //
 810 //     7 Parm #memory
 811 //    10  ConI  "12"
 812 //    19  CheckCastPP   "Foo"
 813 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
 814 //    29  CheckCastPP   "Foo"  iid=24
 815 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
 816 //
 817 //    40  StoreP  25  7   20   ... alias_index=4
 818 //    50  StoreP  35  7   30   ... alias_index=6
 819 //    60  StoreP  45  40  20   ... alias_index=4
 820 //    70  LoadP    _  50  30   ... alias_index=6
 821 //    80  Phi     75  40  60   Memory alias_index=4
 822 //   120  Phi     75  50  50   Memory alias_index=6
 823 //    90  LoadP    _ 120  30   ... alias_index=6
 824 //   100  LoadP    _  80  20   ... alias_index=4
 825 //
 826 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {
 827   GrowableArray<Node *>  memnode_worklist;
 828   GrowableArray<Node *>  mergemem_worklist;
 829   GrowableArray<PhiNode *>  orig_phis;
 830   PhaseGVN  *igvn = _compile->initial_gvn();
 831   uint new_index_start = (uint) _compile->num_alias_types();
 832   VectorSet visited(Thread::current()->resource_area());
 833   VectorSet ptset(Thread::current()->resource_area());
 834 
 835 
 836   //  Phase 1:  Process possible allocations from alloc_worklist.
 837   //  Create instance types for the CheckCastPP for allocations where possible.
 838   while (alloc_worklist.length() != 0) {
 839     Node *n = alloc_worklist.pop();
 840     uint ni = n->_idx;
 841     const TypeOopPtr* tinst = NULL;
 842     if (n->is_Call()) {
 843       CallNode *alloc = n->as_Call();
 844       // copy escape information to call node
 845       PointsToNode* ptn = _nodes->adr_at(alloc->_idx);
 846       PointsToNode::EscapeState es = escape_state(alloc, igvn);
 847       // We have an allocation or call which returns a Java object,
 848       // see if it is unescaped.
 849       if (es != PointsToNode::NoEscape || !ptn->_scalar_replaceable)
 850         continue;
 851       if (alloc->is_Allocate()) {
 852         // Set the scalar_replaceable flag before the next check.
 853         alloc->as_Allocate()->_is_scalar_replaceable = true;
 854       }
 855       // find CheckCastPP of call return value
 856       n = alloc->result_cast();
 857       if (n == NULL ||          // No uses accept Initialize or
 858           !n->is_CheckCastPP()) // not unique CheckCastPP.
 859         continue;
 860       // The inline code for Object.clone() casts the allocation result to
 861       // java.lang.Object and then to the the actual type of the allocated
 862       // object. Detect this case and use the second cast.
 863       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
 864           && igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT) {
 865         Node *cast2 = NULL;
 866         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 867           Node *use = n->fast_out(i);
 868           if (use->is_CheckCastPP()) {
 869             cast2 = use;
 870             break;
 871           }
 872         }
 873         if (cast2 != NULL) {
 874           n = cast2;
 875         } else {
 876           continue;
 877         }
 878       }
 879       set_escape_state(n->_idx, es);
 880       // in order for an object to be stackallocatable, it must be:
 881       //   - a direct allocation (not a call returning an object)
 882       //   - non-escaping
 883       //   - eligible to be a unique type
 884       //   - not determined to be ineligible by escape analysis
 885       set_map(alloc->_idx, n);
 886       set_map(n->_idx, alloc);
 887       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
 888       if (t == NULL)
 889         continue;  // not a TypeInstPtr
 890       tinst = t->cast_to_instance(ni);
 891       igvn->hash_delete(n);
 892       igvn->set_type(n,  tinst);
 893       n->raise_bottom_type(tinst);
 894       igvn->hash_insert(n);
 895       record_for_optimizer(n);
 896       if (alloc->is_Allocate() && ptn->_scalar_replaceable &&
 897           (t->isa_instptr() || t->isa_aryptr())) {
 898 
 899         // First, put on the worklist all Field edges from Connection Graph
 900         // which is more accurate then putting immediate users from Ideal Graph.
 901         for (uint e = 0; e < ptn->edge_count(); e++) {
 902           Node *use = _nodes->adr_at(ptn->edge_target(e))->_node;
 903           assert(ptn->edge_type(e) == PointsToNode::FieldEdge && use->is_AddP(),
 904                  "only AddP nodes are Field edges in CG");
 905           if (use->outcnt() > 0) { // Don't process dead nodes
 906             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
 907             if (addp2 != NULL) {
 908               assert(alloc->is_AllocateArray(),"array allocation was expected");
 909               alloc_worklist.append_if_missing(addp2);
 910             }
 911             alloc_worklist.append_if_missing(use);
 912           }
 913         }
 914 
 915         // An allocation may have an Initialize which has raw stores. Scan
 916         // the users of the raw allocation result and push AddP users
 917         // on alloc_worklist.
 918         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
 919         assert (raw_result != NULL, "must have an allocation result");
 920         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
 921           Node *use = raw_result->fast_out(i);
 922           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
 923             Node* addp2 = find_second_addp(use, raw_result);
 924             if (addp2 != NULL) {
 925               assert(alloc->is_AllocateArray(),"array allocation was expected");
 926               alloc_worklist.append_if_missing(addp2);
 927             }
 928             alloc_worklist.append_if_missing(use);
 929           } else if (use->is_Initialize()) {
 930             memnode_worklist.append_if_missing(use);
 931           }
 932         }
 933       }
 934     } else if (n->is_AddP()) {
 935       ptset.Clear();
 936       PointsTo(ptset, get_addp_base(n), igvn);
 937       assert(ptset.Size() == 1, "AddP address is unique");
 938       uint elem = ptset.getelem(); // Allocation node's index
 939       if (elem == _phantom_object)
 940         continue; // Assume the value was set outside this method.
 941       Node *base = get_map(elem);  // CheckCastPP node
 942       split_AddP(n, base, igvn);
 943       tinst = igvn->type(base)->isa_oopptr();
 944     } else if (n->is_Phi() ||
 945                n->is_CheckCastPP() ||
 946                n->is_EncodeP() ||
 947                n->is_DecodeN() ||
 948                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
 949       if (visited.test_set(n->_idx)) {
 950         assert(n->is_Phi(), "loops only through Phi's");
 951         continue;  // already processed
 952       }
 953       ptset.Clear();
 954       PointsTo(ptset, n, igvn);
 955       if (ptset.Size() == 1) {
 956         uint elem = ptset.getelem(); // Allocation node's index
 957         if (elem == _phantom_object)
 958           continue; // Assume the value was set outside this method.
 959         Node *val = get_map(elem);   // CheckCastPP node
 960         TypeNode *tn = n->as_Type();
 961         tinst = igvn->type(val)->isa_oopptr();
 962         assert(tinst != NULL && tinst->is_instance() &&
 963                tinst->instance_id() == elem , "instance type expected.");
 964 
 965         const Type *tn_type = igvn->type(tn);
 966         const TypeOopPtr *tn_t = tn_type->make_ptr()->isa_oopptr();
 967 
 968         if (tn_t != NULL &&
 969  tinst->cast_to_instance(TypeOopPtr::UNKNOWN_INSTANCE)->higher_equal(tn_t)) {
 970           if (tn_type->isa_narrowoop()) {
 971             tn_type = tinst->make_narrowoop();
 972           } else {
 973             tn_type = tinst;
 974           }
 975           igvn->hash_delete(tn);
 976           igvn->set_type(tn, tn_type);
 977           tn->set_type(tn_type);
 978           igvn->hash_insert(tn);
 979           record_for_optimizer(n);
 980         }
 981       }
 982     } else {
 983       continue;
 984     }
 985     // push users on appropriate worklist
 986     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 987       Node *use = n->fast_out(i);
 988       if(use->is_Mem() && use->in(MemNode::Address) == n) {
 989         memnode_worklist.append_if_missing(use);
 990       } else if (use->is_Initialize()) {
 991         memnode_worklist.append_if_missing(use);
 992       } else if (use->is_MergeMem()) {
 993         mergemem_worklist.append_if_missing(use);
 994       } else if (use->is_Call() && tinst != NULL) {
 995         // Look for MergeMem nodes for calls which reference unique allocation
 996         // (through CheckCastPP nodes) even for debug info.
 997         Node* m = use->in(TypeFunc::Memory);
 998         uint iid = tinst->instance_id();
 999         while (m->is_Proj() && m->in(0)->is_Call() &&
1000                m->in(0) != use && !m->in(0)->_idx != iid) {
1001           m = m->in(0)->in(TypeFunc::Memory);
1002         }
1003         if (m->is_MergeMem()) {
1004           mergemem_worklist.append_if_missing(m);
1005         }
1006       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
1007         Node* addp2 = find_second_addp(use, n);
1008         if (addp2 != NULL) {
1009           alloc_worklist.append_if_missing(addp2);
1010         }
1011         alloc_worklist.append_if_missing(use);
1012       } else if (use->is_Phi() ||
1013                  use->is_CheckCastPP() ||
1014                  use->is_EncodeP() ||
1015                  use->is_DecodeN() ||
1016                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
1017         alloc_worklist.append_if_missing(use);
1018       }
1019     }
1020 
1021   }
1022   // New alias types were created in split_AddP().
1023   uint new_index_end = (uint) _compile->num_alias_types();
1024 
1025   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
1026   //            compute new values for Memory inputs  (the Memory inputs are not
1027   //            actually updated until phase 4.)
1028   if (memnode_worklist.length() == 0)
1029     return;  // nothing to do
1030 
1031   while (memnode_worklist.length() != 0) {
1032     Node *n = memnode_worklist.pop();
1033     if (visited.test_set(n->_idx))
1034       continue;
1035     if (n->is_Phi()) {
1036       assert(n->as_Phi()->adr_type() != TypePtr::BOTTOM, "narrow memory slice required");
1037       // we don't need to do anything, but the users must be pushed if we haven't processed
1038       // this Phi before
1039     } else if (n->is_Initialize()) {
1040       // we don't need to do anything, but the users of the memory projection must be pushed
1041       n = n->as_Initialize()->proj_out(TypeFunc::Memory);
1042       if (n == NULL)
1043         continue;
1044     } else {
1045       assert(n->is_Mem(), "memory node required.");
1046       Node *addr = n->in(MemNode::Address);
1047       assert(addr->is_AddP(), "AddP required");
1048       const Type *addr_t = igvn->type(addr);
1049       if (addr_t == Type::TOP)
1050         continue;
1051       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
1052       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
1053       assert ((uint)alias_idx < new_index_end, "wrong alias index");
1054       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis, igvn);
1055       if (_compile->failing()) {
1056         return;
1057       }
1058       if (mem != n->in(MemNode::Memory)) {
1059         set_map(n->_idx, mem);
1060         _nodes->adr_at(n->_idx)->_node = n;
1061       }
1062       if (n->is_Load()) {
1063         continue;  // don't push users
1064       } else if (n->is_LoadStore()) {
1065         // get the memory projection
1066         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1067           Node *use = n->fast_out(i);
1068           if (use->Opcode() == Op_SCMemProj) {
1069             n = use;
1070             break;
1071           }
1072         }
1073         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
1074       }
1075     }
1076     // push user on appropriate worklist
1077     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1078       Node *use = n->fast_out(i);
1079       if (use->is_Phi()) {
1080         memnode_worklist.append_if_missing(use);
1081       } else if(use->is_Mem() && use->in(MemNode::Memory) == n) {
1082         memnode_worklist.append_if_missing(use);
1083       } else if (use->is_Initialize()) {
1084         memnode_worklist.append_if_missing(use);
1085       } else if (use->is_MergeMem()) {
1086         mergemem_worklist.append_if_missing(use);
1087       }
1088     }
1089   }
1090 
1091   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
1092   //            Walk each memory moving the first node encountered of each
1093   //            instance type to the the input corresponding to its alias index.
1094   while (mergemem_worklist.length() != 0) {
1095     Node *n = mergemem_worklist.pop();
1096     assert(n->is_MergeMem(), "MergeMem node required.");
1097     if (visited.test_set(n->_idx))
1098       continue;
1099     MergeMemNode *nmm = n->as_MergeMem();
1100     // Note: we don't want to use MergeMemStream here because we only want to
1101     //  scan inputs which exist at the start, not ones we add during processing.
1102     uint nslices = nmm->req();
1103     igvn->hash_delete(nmm);
1104     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
1105       Node* mem = nmm->in(i);
1106       Node* cur = NULL;
1107       if (mem == NULL || mem->is_top())
1108         continue;
1109       while (mem->is_Mem()) {
1110         const Type *at = igvn->type(mem->in(MemNode::Address));
1111         if (at != Type::TOP) {
1112           assert (at->isa_ptr() != NULL, "pointer type required.");
1113           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
1114           if (idx == i) {
1115             if (cur == NULL)
1116               cur = mem;
1117           } else {
1118             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
1119               nmm->set_memory_at(idx, mem);
1120             }
1121           }
1122         }
1123         mem = mem->in(MemNode::Memory);
1124       }
1125       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
1126       // Find any instance of the current type if we haven't encountered
1127       // a value of the instance along the chain.
1128       for (uint ni = new_index_start; ni < new_index_end; ni++) {
1129         if((uint)_compile->get_general_index(ni) == i) {
1130           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
1131           if (nmm->is_empty_memory(m)) {
1132             Node* result = find_inst_mem(mem, ni, orig_phis, igvn);
1133             if (_compile->failing()) {
1134               return;
1135             }
1136             nmm->set_memory_at(ni, result);
1137           }
1138         }
1139       }
1140     }
1141     // Find the rest of instances values
1142     for (uint ni = new_index_start; ni < new_index_end; ni++) {
1143       const TypeOopPtr *tinst = igvn->C->get_adr_type(ni)->isa_oopptr();
1144       Node* result = step_through_mergemem(nmm, ni, tinst);
1145       if (result == nmm->base_memory()) {
1146         // Didn't find instance memory, search through general slice recursively.
1147         result = nmm->memory_at(igvn->C->get_general_index(ni));
1148         result = find_inst_mem(result, ni, orig_phis, igvn);
1149         if (_compile->failing()) {
1150           return;
1151         }
1152         nmm->set_memory_at(ni, result);
1153       }
1154     }
1155     igvn->hash_insert(nmm);
1156     record_for_optimizer(nmm);
1157 
1158     // Propagate new memory slices to following MergeMem nodes.
1159     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1160       Node *use = n->fast_out(i);
1161       if (use->is_Call()) {
1162         CallNode* in = use->as_Call();
1163         if (in->proj_out(TypeFunc::Memory) != NULL) {
1164           Node* m = in->proj_out(TypeFunc::Memory);
1165           for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
1166             Node* mm = m->fast_out(j);
1167             if (mm->is_MergeMem()) {
1168               mergemem_worklist.append_if_missing(mm);
1169             }
1170           }
1171         }
1172         if (use->is_Allocate()) {
1173           use = use->as_Allocate()->initialization();
1174           if (use == NULL) {
1175             continue;
1176           }
1177         }
1178       }
1179       if (use->is_Initialize()) {
1180         InitializeNode* in = use->as_Initialize();
1181         if (in->proj_out(TypeFunc::Memory) != NULL) {
1182           Node* m = in->proj_out(TypeFunc::Memory);
1183           for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
1184             Node* mm = m->fast_out(j);
1185             if (mm->is_MergeMem()) {
1186               mergemem_worklist.append_if_missing(mm);
1187             }
1188           }
1189         }
1190       }
1191     }
1192   }
1193 
1194   //  Phase 4:  Update the inputs of non-instance memory Phis and
1195   //            the Memory input of memnodes
1196   // First update the inputs of any non-instance Phi's from
1197   // which we split out an instance Phi.  Note we don't have
1198   // to recursively process Phi's encounted on the input memory
1199   // chains as is done in split_memory_phi() since they  will
1200   // also be processed here.
1201   while (orig_phis.length() != 0) {
1202     PhiNode *phi = orig_phis.pop();
1203     int alias_idx = _compile->get_alias_index(phi->adr_type());
1204     igvn->hash_delete(phi);
1205     for (uint i = 1; i < phi->req(); i++) {
1206       Node *mem = phi->in(i);
1207       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis, igvn);
1208       if (_compile->failing()) {
1209         return;
1210       }
1211       if (mem != new_mem) {
1212         phi->set_req(i, new_mem);
1213       }
1214     }
1215     igvn->hash_insert(phi);
1216     record_for_optimizer(phi);
1217   }
1218 
1219   // Update the memory inputs of MemNodes with the value we computed
1220   // in Phase 2.
1221   for (int i = 0; i < _nodes->length(); i++) {
1222     Node *nmem = get_map(i);
1223     if (nmem != NULL) {
1224       Node *n = _nodes->adr_at(i)->_node;
1225       if (n != NULL && n->is_Mem()) {
1226         igvn->hash_delete(n);
1227         n->set_req(MemNode::Memory, nmem);
1228         igvn->hash_insert(n);
1229         record_for_optimizer(n);
1230       }
1231     }
1232   }
1233 }
1234 
1235 void ConnectionGraph::compute_escape() {
1236 
1237   // 1. Populate Connection Graph (CG) with Ideal nodes.
1238 
1239   Unique_Node_List worklist_init;
1240   worklist_init.map(_compile->unique(), NULL);  // preallocate space
1241 
1242   // Initialize worklist
1243   if (_compile->root() != NULL) {
1244     worklist_init.push(_compile->root());
1245   }
1246 
1247   GrowableArray<int> cg_worklist;
1248   PhaseGVN* igvn = _compile->initial_gvn();
1249   bool has_allocations = false;
1250 
1251   // Push all useful nodes onto CG list and set their type.
1252   for( uint next = 0; next < worklist_init.size(); ++next ) {
1253     Node* n = worklist_init.at(next);
1254     record_for_escape_analysis(n, igvn);
1255     if (n->is_Call() &&
1256         _nodes->adr_at(n->_idx)->node_type() == PointsToNode::JavaObject) {
1257       has_allocations = true;
1258     }
1259     if(n->is_AddP())
1260       cg_worklist.append(n->_idx);
1261     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1262       Node* m = n->fast_out(i);   // Get user
1263       worklist_init.push(m);
1264     }
1265   }
1266 
1267   if (has_allocations) {
1268     _has_allocations = true;
1269   } else {
1270     _has_allocations = false;
1271     _collecting = false;
1272     return; // Nothing to do.
1273   }
1274 
1275   // 2. First pass to create simple CG edges (doesn't require to walk CG).
1276   for( uint next = 0; next < _delayed_worklist.size(); ++next ) {
1277     Node* n = _delayed_worklist.at(next);
1278     build_connection_graph(n, igvn);
1279   }
1280 
1281   // 3. Pass to create fields edges (Allocate -F-> AddP).
1282   for( int next = 0; next < cg_worklist.length(); ++next ) {
1283     int ni = cg_worklist.at(next);
1284     build_connection_graph(_nodes->adr_at(ni)->_node, igvn);
1285   }
1286 
1287   cg_worklist.clear();
1288   cg_worklist.append(_phantom_object);
1289 
1290   // 4. Build Connection Graph which need
1291   //    to walk the connection graph.
1292   for (uint ni = 0; ni < (uint)_nodes->length(); ni++) {
1293     PointsToNode* ptn = _nodes->adr_at(ni);
1294     Node *n = ptn->_node;
1295     if (n != NULL) { // Call, AddP, LoadP, StoreP
1296       build_connection_graph(n, igvn);
1297       if (ptn->node_type() != PointsToNode::UnknownType)
1298         cg_worklist.append(n->_idx); // Collect CG nodes
1299     }
1300   }
1301 
1302   VectorSet ptset(Thread::current()->resource_area());
1303   GrowableArray<Node*> alloc_worklist;
1304   GrowableArray<int>   worklist;
1305   GrowableArray<uint>  deferred_edges;
1306   VectorSet visited(Thread::current()->resource_area());
1307 
1308   // remove deferred edges from the graph and collect
1309   // information we will need for type splitting
1310   for( int next = 0; next < cg_worklist.length(); ++next ) {
1311     int ni = cg_worklist.at(next);
1312     PointsToNode* ptn = _nodes->adr_at(ni);
1313     PointsToNode::NodeType nt = ptn->node_type();
1314     Node *n = ptn->_node;
1315     if (nt == PointsToNode::LocalVar || nt == PointsToNode::Field) {
1316       remove_deferred(ni, &deferred_edges, &visited);
1317       if (n->is_AddP()) {
1318         // If this AddP computes an address which may point to more that one
1319         // object or more then one field (array's element), nothing the address
1320         // points to can be scalar replaceable.
1321         Node *base = get_addp_base(n);
1322         ptset.Clear();
1323         PointsTo(ptset, base, igvn);
1324         if (ptset.Size() > 1 ||
1325             (ptset.Size() != 0 && ptn->offset() == Type::OffsetBot)) {
1326           for( VectorSetI j(&ptset); j.test(); ++j ) {
1327             uint pt = j.elem;
1328             ptnode_adr(pt)->_scalar_replaceable = false;
1329           }
1330         }
1331       }
1332     } else if (nt == PointsToNode::JavaObject && n->is_Call()) {
1333       // Push call on alloc_worlist (alocations are calls)
1334       // for processing by split_unique_types().
1335       alloc_worklist.append(n);
1336     }
1337   }
1338 
1339   // push all GlobalEscape nodes on the worklist
1340   for( int next = 0; next < cg_worklist.length(); ++next ) {
1341     int nk = cg_worklist.at(next);
1342     if (_nodes->adr_at(nk)->escape_state() == PointsToNode::GlobalEscape)
1343       worklist.append(nk);
1344   }
1345   // mark all node reachable from GlobalEscape nodes
1346   while(worklist.length() > 0) {
1347     PointsToNode n = _nodes->at(worklist.pop());
1348     for (uint ei = 0; ei < n.edge_count(); ei++) {
1349       uint npi = n.edge_target(ei);
1350       PointsToNode *np = ptnode_adr(npi);
1351       if (np->escape_state() < PointsToNode::GlobalEscape) {
1352         np->set_escape_state(PointsToNode::GlobalEscape);
1353         worklist.append_if_missing(npi);
1354       }
1355     }
1356   }
1357 
1358   // push all ArgEscape nodes on the worklist
1359   for( int next = 0; next < cg_worklist.length(); ++next ) {
1360     int nk = cg_worklist.at(next);
1361     if (_nodes->adr_at(nk)->escape_state() == PointsToNode::ArgEscape)
1362       worklist.push(nk);
1363   }
1364   // mark all node reachable from ArgEscape nodes
1365   while(worklist.length() > 0) {
1366     PointsToNode n = _nodes->at(worklist.pop());
1367     for (uint ei = 0; ei < n.edge_count(); ei++) {
1368       uint npi = n.edge_target(ei);
1369       PointsToNode *np = ptnode_adr(npi);
1370       if (np->escape_state() < PointsToNode::ArgEscape) {
1371         np->set_escape_state(PointsToNode::ArgEscape);
1372         worklist.append_if_missing(npi);
1373       }
1374     }
1375   }
1376 
1377   // push all NoEscape nodes on the worklist
1378   for( int next = 0; next < cg_worklist.length(); ++next ) {
1379     int nk = cg_worklist.at(next);
1380     if (_nodes->adr_at(nk)->escape_state() == PointsToNode::NoEscape)
1381       worklist.push(nk);
1382   }
1383   // mark all node reachable from NoEscape nodes
1384   while(worklist.length() > 0) {
1385     PointsToNode n = _nodes->at(worklist.pop());
1386     for (uint ei = 0; ei < n.edge_count(); ei++) {
1387       uint npi = n.edge_target(ei);
1388       PointsToNode *np = ptnode_adr(npi);
1389       if (np->escape_state() < PointsToNode::NoEscape) {
1390         np->set_escape_state(PointsToNode::NoEscape);
1391         worklist.append_if_missing(npi);
1392       }
1393     }
1394   }
1395 
1396   _collecting = false;
1397 
1398   has_allocations = false; // Are there scalar replaceable allocations?
1399 
1400   for( int next = 0; next < alloc_worklist.length(); ++next ) {
1401     Node* n = alloc_worklist.at(next);
1402     uint ni = n->_idx;
1403     PointsToNode* ptn = _nodes->adr_at(ni);
1404     PointsToNode::EscapeState es = ptn->escape_state();
1405     if (ptn->escape_state() == PointsToNode::NoEscape &&
1406         ptn->_scalar_replaceable) {
1407       has_allocations = true;
1408       break;
1409     }
1410   }
1411   if (!has_allocations) {
1412     return; // Nothing to do.
1413   }
1414 
1415   if(_compile->AliasLevel() >= 3 && EliminateAllocations) {
1416     // Now use the escape information to create unique types for
1417     // unescaped objects
1418     split_unique_types(alloc_worklist);
1419     if (_compile->failing())  return;
1420 
1421     // Clean up after split unique types.
1422     ResourceMark rm;
1423     PhaseRemoveUseless pru(_compile->initial_gvn(), _compile->for_igvn());
1424 
1425 #ifdef ASSERT
1426   } else if (PrintEscapeAnalysis || PrintEliminateAllocations) {
1427     tty->print("=== No allocations eliminated for ");
1428     C()->method()->print_short_name();
1429     if(!EliminateAllocations) {
1430       tty->print(" since EliminateAllocations is off ===");
1431     } else if(_compile->AliasLevel() < 3) {
1432       tty->print(" since AliasLevel < 3 ===");
1433     }
1434     tty->cr();
1435 #endif
1436   }
1437 }
1438 
1439 void ConnectionGraph::process_call_arguments(CallNode *call, PhaseTransform *phase) {
1440 
1441     switch (call->Opcode()) {
1442 #ifdef ASSERT
1443     case Op_Allocate:
1444     case Op_AllocateArray:
1445     case Op_Lock:
1446     case Op_Unlock:
1447       assert(false, "should be done already");
1448       break;
1449 #endif
1450     case Op_CallLeafNoFP:
1451     {
1452       // Stub calls, objects do not escape but they are not scale replaceable.
1453       // Adjust escape state for outgoing arguments.
1454       const TypeTuple * d = call->tf()->domain();
1455       VectorSet ptset(Thread::current()->resource_area());
1456       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1457         const Type* at = d->field_at(i);
1458         Node *arg = call->in(i)->uncast();
1459         const Type *aat = phase->type(arg);
1460         if (!arg->is_top() && at->isa_ptr() && aat->isa_ptr()) {
1461           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
1462                  aat->isa_ptr() != NULL, "expecting an Ptr");
1463           set_escape_state(arg->_idx, PointsToNode::ArgEscape);
1464           if (arg->is_AddP()) {
1465             //
1466             // The inline_native_clone() case when the arraycopy stub is called
1467             // after the allocation before Initialize and CheckCastPP nodes.
1468             //
1469             // Set AddP's base (Allocate) as not scalar replaceable since
1470             // pointer to the base (with offset) is passed as argument.
1471             //
1472             arg = get_addp_base(arg);
1473           }
1474           ptset.Clear();
1475           PointsTo(ptset, arg, phase);
1476           for( VectorSetI j(&ptset); j.test(); ++j ) {
1477             uint pt = j.elem;
1478             set_escape_state(pt, PointsToNode::ArgEscape);
1479           }
1480         }
1481       }
1482       break;
1483     }
1484 
1485     case Op_CallStaticJava:
1486     // For a static call, we know exactly what method is being called.
1487     // Use bytecode estimator to record the call's escape affects
1488     {
1489       ciMethod *meth = call->as_CallJava()->method();
1490       BCEscapeAnalyzer *call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1491       // fall-through if not a Java method or no analyzer information
1492       if (call_analyzer != NULL) {
1493         const TypeTuple * d = call->tf()->domain();
1494         VectorSet ptset(Thread::current()->resource_area());
1495         bool copy_dependencies = false;
1496         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1497           const Type* at = d->field_at(i);
1498           int k = i - TypeFunc::Parms;
1499 
1500           if (at->isa_oopptr() != NULL) {
1501             Node *arg = call->in(i)->uncast();
1502 
1503             bool global_escapes = false;
1504             bool fields_escapes = false;
1505             if (!call_analyzer->is_arg_stack(k)) {
1506               // The argument global escapes, mark everything it could point to
1507               set_escape_state(arg->_idx, PointsToNode::GlobalEscape);
1508               global_escapes = true;
1509             } else {
1510               if (!call_analyzer->is_arg_local(k)) {
1511                 // The argument itself doesn't escape, but any fields might
1512                 fields_escapes = true;
1513               }
1514               set_escape_state(arg->_idx, PointsToNode::ArgEscape);
1515               copy_dependencies = true;
1516             }
1517 
1518             ptset.Clear();
1519             PointsTo(ptset, arg, phase);
1520             for( VectorSetI j(&ptset); j.test(); ++j ) {
1521               uint pt = j.elem;
1522               if (global_escapes) {
1523                 //The argument global escapes, mark everything it could point to
1524                 set_escape_state(pt, PointsToNode::GlobalEscape);
1525               } else {
1526                 if (fields_escapes) {
1527                   // The argument itself doesn't escape, but any fields might
1528                   add_edge_from_fields(pt, _phantom_object, Type::OffsetBot);
1529                 }
1530                 set_escape_state(pt, PointsToNode::ArgEscape);
1531               }
1532             }
1533           }
1534         }
1535         if (copy_dependencies)
1536           call_analyzer->copy_dependencies(C()->dependencies());
1537         break;
1538       }
1539     }
1540 
1541     default:
1542     // Fall-through here if not a Java method or no analyzer information
1543     // or some other type of call, assume the worst case: all arguments
1544     // globally escape.
1545     {
1546       // adjust escape state for  outgoing arguments
1547       const TypeTuple * d = call->tf()->domain();
1548       VectorSet ptset(Thread::current()->resource_area());
1549       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1550         const Type* at = d->field_at(i);
1551         if (at->isa_oopptr() != NULL) {
1552           Node *arg = call->in(i)->uncast();
1553           set_escape_state(arg->_idx, PointsToNode::GlobalEscape);
1554           ptset.Clear();
1555           PointsTo(ptset, arg, phase);
1556           for( VectorSetI j(&ptset); j.test(); ++j ) {
1557             uint pt = j.elem;
1558             set_escape_state(pt, PointsToNode::GlobalEscape);
1559             PointsToNode *ptadr = ptnode_adr(pt);
1560           }
1561         }
1562       }
1563     }
1564   }
1565 }
1566 void ConnectionGraph::process_call_result(ProjNode *resproj, PhaseTransform *phase) {
1567   PointsToNode *ptadr = ptnode_adr(resproj->_idx);
1568 
1569   CallNode *call = resproj->in(0)->as_Call();
1570   switch (call->Opcode()) {
1571     case Op_Allocate:
1572     {
1573       Node *k = call->in(AllocateNode::KlassNode);
1574       const TypeKlassPtr *kt;
1575       if (k->Opcode() == Op_LoadKlass) {
1576         kt = k->as_Load()->type()->isa_klassptr();
1577       } else {
1578         // Also works for DecodeN(LoadNKlass).
1579         kt = k->as_Type()->type()->isa_klassptr();
1580       }
1581       assert(kt != NULL, "TypeKlassPtr  required.");
1582       ciKlass* cik = kt->klass();
1583       ciInstanceKlass* ciik = cik->as_instance_klass();
1584 
1585       PointsToNode *ptadr = ptnode_adr(call->_idx);
1586       PointsToNode::EscapeState es;
1587       uint edge_to;
1588       if (cik->is_subclass_of(_compile->env()->Thread_klass()) || ciik->has_finalizer()) {
1589         es = PointsToNode::GlobalEscape;
1590         edge_to = _phantom_object; // Could not be worse
1591       } else {
1592         es = PointsToNode::NoEscape;
1593         edge_to = call->_idx;
1594       }
1595       set_escape_state(call->_idx, es);
1596       add_pointsto_edge(resproj->_idx, edge_to);
1597       _processed.set(resproj->_idx);
1598       break;
1599     }
1600 
1601     case Op_AllocateArray:
1602     {
1603       PointsToNode *ptadr = ptnode_adr(call->_idx);
1604       int length = call->in(AllocateNode::ALength)->find_int_con(-1);
1605       if (length < 0 || length > EliminateAllocationArraySizeLimit) {
1606         // Not scalar replaceable if the length is not constant or too big.
1607         ptadr->_scalar_replaceable = false;
1608       }
1609       set_escape_state(call->_idx, PointsToNode::NoEscape);
1610       add_pointsto_edge(resproj->_idx, call->_idx);
1611       _processed.set(resproj->_idx);
1612       break;
1613     }
1614 
1615     case Op_CallStaticJava:
1616     // For a static call, we know exactly what method is being called.
1617     // Use bytecode estimator to record whether the call's return value escapes
1618     {
1619       bool done = true;
1620       const TypeTuple *r = call->tf()->range();
1621       const Type* ret_type = NULL;
1622 
1623       if (r->cnt() > TypeFunc::Parms)
1624         ret_type = r->field_at(TypeFunc::Parms);
1625 
1626       // Note:  we use isa_ptr() instead of isa_oopptr()  here because the
1627       //        _multianewarray functions return a TypeRawPtr.
1628       if (ret_type == NULL || ret_type->isa_ptr() == NULL) {
1629         _processed.set(resproj->_idx);
1630         break;  // doesn't return a pointer type
1631       }
1632       ciMethod *meth = call->as_CallJava()->method();
1633       const TypeTuple * d = call->tf()->domain();
1634       if (meth == NULL) {
1635         // not a Java method, assume global escape
1636         set_escape_state(call->_idx, PointsToNode::GlobalEscape);
1637         if (resproj != NULL)
1638           add_pointsto_edge(resproj->_idx, _phantom_object);
1639       } else {
1640         BCEscapeAnalyzer *call_analyzer = meth->get_bcea();
1641         VectorSet ptset(Thread::current()->resource_area());
1642         bool copy_dependencies = false;
1643 
1644         if (call_analyzer->is_return_allocated()) {
1645           // Returns a newly allocated unescaped object, simply
1646           // update dependency information.
1647           // Mark it as NoEscape so that objects referenced by
1648           // it's fields will be marked as NoEscape at least.
1649           set_escape_state(call->_idx, PointsToNode::NoEscape);
1650           if (resproj != NULL)
1651             add_pointsto_edge(resproj->_idx, call->_idx);
1652           copy_dependencies = true;
1653         } else if (call_analyzer->is_return_local() && resproj != NULL) {
1654           // determine whether any arguments are returned
1655           set_escape_state(call->_idx, PointsToNode::NoEscape);
1656           for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1657             const Type* at = d->field_at(i);
1658 
1659             if (at->isa_oopptr() != NULL) {
1660               Node *arg = call->in(i)->uncast();
1661 
1662               if (call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
1663                 PointsToNode *arg_esp = _nodes->adr_at(arg->_idx);
1664                 if (arg_esp->node_type() == PointsToNode::UnknownType)
1665                   done = false;
1666                 else if (arg_esp->node_type() == PointsToNode::JavaObject)
1667                   add_pointsto_edge(resproj->_idx, arg->_idx);
1668                 else
1669                   add_deferred_edge(resproj->_idx, arg->_idx);
1670                 arg_esp->_hidden_alias = true;
1671               }
1672             }
1673           }
1674           copy_dependencies = true;
1675         } else {
1676           set_escape_state(call->_idx, PointsToNode::GlobalEscape);
1677           if (resproj != NULL)
1678             add_pointsto_edge(resproj->_idx, _phantom_object);
1679           for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1680             const Type* at = d->field_at(i);
1681             if (at->isa_oopptr() != NULL) {
1682               Node *arg = call->in(i)->uncast();
1683               PointsToNode *arg_esp = _nodes->adr_at(arg->_idx);
1684               arg_esp->_hidden_alias = true;
1685             }
1686           }
1687         }
1688         if (copy_dependencies)
1689           call_analyzer->copy_dependencies(C()->dependencies());
1690       }
1691       if (done)
1692         _processed.set(resproj->_idx);
1693       break;
1694     }
1695 
1696     default:
1697     // Some other type of call, assume the worst case that the
1698     // returned value, if any, globally escapes.
1699     {
1700       const TypeTuple *r = call->tf()->range();
1701       if (r->cnt() > TypeFunc::Parms) {
1702         const Type* ret_type = r->field_at(TypeFunc::Parms);
1703 
1704         // Note:  we use isa_ptr() instead of isa_oopptr()  here because the
1705         //        _multianewarray functions return a TypeRawPtr.
1706         if (ret_type->isa_ptr() != NULL) {
1707           PointsToNode *ptadr = ptnode_adr(call->_idx);
1708           set_escape_state(call->_idx, PointsToNode::GlobalEscape);
1709           if (resproj != NULL)
1710             add_pointsto_edge(resproj->_idx, _phantom_object);
1711         }
1712       }
1713       _processed.set(resproj->_idx);
1714     }
1715   }
1716 }
1717 
1718 // Populate Connection Graph with Ideal nodes and create simple
1719 // connection graph edges (do not need to check the node_type of inputs
1720 // or to call PointsTo() to walk the connection graph).
1721 void ConnectionGraph::record_for_escape_analysis(Node *n, PhaseTransform *phase) {
1722   if (_processed.test(n->_idx))
1723     return; // No need to redefine node's state.
1724 
1725   if (n->is_Call()) {
1726     // Arguments to allocation and locking don't escape.
1727     if (n->is_Allocate()) {
1728       add_node(n, PointsToNode::JavaObject, PointsToNode::UnknownEscape, true);
1729       record_for_optimizer(n);
1730     } else if (n->is_Lock() || n->is_Unlock()) {
1731       // Put Lock and Unlock nodes on IGVN worklist to process them during
1732       // the first IGVN optimization when escape information is still available.
1733       record_for_optimizer(n);
1734       _processed.set(n->_idx);
1735     } else {
1736       // Have to process call's arguments first.
1737       PointsToNode::NodeType nt = PointsToNode::UnknownType;
1738 
1739       // Check if a call returns an object.
1740       const TypeTuple *r = n->as_Call()->tf()->range();
1741       if (r->cnt() > TypeFunc::Parms &&
1742           n->as_Call()->proj_out(TypeFunc::Parms) != NULL) {
1743         // Note:  use isa_ptr() instead of isa_oopptr() here because
1744         //        the _multianewarray functions return a TypeRawPtr.
1745         if (r->field_at(TypeFunc::Parms)->isa_ptr() != NULL) {
1746           nt = PointsToNode::JavaObject;
1747         }
1748       }
1749       add_node(n, nt, PointsToNode::UnknownEscape, false);
1750     }
1751     return;
1752   }
1753 
1754   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1755   // ThreadLocal has RawPrt type.
1756   switch (n->Opcode()) {
1757     case Op_AddP:
1758     {
1759       add_node(n, PointsToNode::Field, PointsToNode::UnknownEscape, false);
1760       break;
1761     }
1762     case Op_CastX2P:
1763     { // "Unsafe" memory access.
1764       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);
1765       break;
1766     }
1767     case Op_CastPP:
1768     case Op_CheckCastPP:
1769     case Op_EncodeP:
1770     case Op_DecodeN:
1771     {
1772       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);
1773       int ti = n->in(1)->_idx;
1774       PointsToNode::NodeType nt = _nodes->adr_at(ti)->node_type();
1775       if (nt == PointsToNode::UnknownType) {
1776         _delayed_worklist.push(n); // Process it later.
1777         break;
1778       } else if (nt == PointsToNode::JavaObject) {
1779         add_pointsto_edge(n->_idx, ti);
1780       } else {
1781         add_deferred_edge(n->_idx, ti);
1782       }
1783       _processed.set(n->_idx);
1784       break;
1785     }
1786     case Op_ConP:
1787     {
1788       // assume all pointer constants globally escape except for null
1789       PointsToNode::EscapeState es;
1790       if (phase->type(n) == TypePtr::NULL_PTR)
1791         es = PointsToNode::NoEscape;
1792       else
1793         es = PointsToNode::GlobalEscape;
1794 
1795       add_node(n, PointsToNode::JavaObject, es, true);
1796       break;
1797     }
1798     case Op_ConN:
1799     {
1800       // assume all narrow oop constants globally escape except for null
1801       PointsToNode::EscapeState es;
1802       if (phase->type(n) == TypeNarrowOop::NULL_PTR)
1803         es = PointsToNode::NoEscape;
1804       else
1805         es = PointsToNode::GlobalEscape;
1806 
1807       add_node(n, PointsToNode::JavaObject, es, true);
1808       break;
1809     }
1810     case Op_CreateEx:
1811     {
1812       // assume that all exception objects globally escape
1813       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);
1814       break;
1815     }
1816     case Op_LoadKlass:
1817     case Op_LoadNKlass:
1818     {
1819       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, true);
1820       break;
1821     }
1822     case Op_LoadP:
1823     case Op_LoadN:
1824     {
1825       const Type *t = phase->type(n);
1826       if (!t->isa_narrowoop() && t->isa_ptr() == NULL) {
1827         _processed.set(n->_idx);
1828         return;
1829       }
1830       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);
1831       break;
1832     }
1833     case Op_Parm:
1834     {
1835       _processed.set(n->_idx); // No need to redefine it state.
1836       uint con = n->as_Proj()->_con;
1837       if (con < TypeFunc::Parms)
1838         return;
1839       const Type *t = n->in(0)->as_Start()->_domain->field_at(con);
1840       if (t->isa_ptr() == NULL)
1841         return;
1842       // We have to assume all input parameters globally escape
1843       // (Note: passing 'false' since _processed is already set).
1844       add_node(n, PointsToNode::JavaObject, PointsToNode::GlobalEscape, false);
1845       break;
1846     }
1847     case Op_Phi:
1848     {
1849       if (n->as_Phi()->type()->isa_ptr() == NULL) {
1850         // nothing to do if not an oop
1851         _processed.set(n->_idx);
1852         return;
1853       }
1854       add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);
1855       uint i;
1856       for (i = 1; i < n->req() ; i++) {
1857         Node* in = n->in(i);
1858         if (in == NULL)
1859           continue;  // ignore NULL
1860         in = in->uncast();
1861         if (in->is_top() || in == n)
1862           continue;  // ignore top or inputs which go back this node
1863         int ti = in->_idx;
1864         PointsToNode::NodeType nt = _nodes->adr_at(ti)->node_type();
1865         if (nt == PointsToNode::UnknownType) {
1866           break;
1867         } else if (nt == PointsToNode::JavaObject) {
1868           add_pointsto_edge(n->_idx, ti);
1869         } else {
1870           add_deferred_edge(n->_idx, ti);
1871         }
1872       }
1873       if (i >= n->req())
1874         _processed.set(n->_idx);
1875       else
1876         _delayed_worklist.push(n);
1877       break;
1878     }
1879     case Op_Proj:
1880     {
1881       // we are only interested in the result projection from a call
1882       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() ) {
1883         add_node(n, PointsToNode::LocalVar, PointsToNode::UnknownEscape, false);
1884         process_call_result(n->as_Proj(), phase);
1885         if (!_processed.test(n->_idx)) {
1886           // The call's result may need to be processed later if the call
1887           // returns it's argument and the argument is not processed yet.
1888           _delayed_worklist.push(n);
1889         }
1890       } else {
1891         _processed.set(n->_idx);
1892       }
1893       break;
1894     }
1895     case Op_Return:
1896     {
1897       if( n->req() > TypeFunc::Parms &&
1898           phase->type(n->in(TypeFunc::Parms))->isa_oopptr() ) {
1899         // Treat Return value as LocalVar with GlobalEscape escape state.
1900         add_node(n, PointsToNode::LocalVar, PointsToNode::GlobalEscape, false);
1901         int ti = n->in(TypeFunc::Parms)->_idx;
1902         PointsToNode::NodeType nt = _nodes->adr_at(ti)->node_type();
1903         if (nt == PointsToNode::UnknownType) {
1904           _delayed_worklist.push(n); // Process it later.
1905           break;
1906         } else if (nt == PointsToNode::JavaObject) {
1907           add_pointsto_edge(n->_idx, ti);
1908         } else {
1909           add_deferred_edge(n->_idx, ti);
1910         }
1911       }
1912       _processed.set(n->_idx);
1913       break;
1914     }
1915     case Op_StoreP:
1916     case Op_StoreN:
1917     {
1918       const Type *adr_type = phase->type(n->in(MemNode::Address));
1919       adr_type = adr_type->make_ptr();
1920       if (adr_type->isa_oopptr()) {
1921         add_node(n, PointsToNode::UnknownType, PointsToNode::UnknownEscape, false);
1922       } else {
1923         Node* adr = n->in(MemNode::Address);
1924         if (adr->is_AddP() && phase->type(adr) == TypeRawPtr::NOTNULL &&
1925             adr->in(AddPNode::Address)->is_Proj() &&
1926             adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
1927           add_node(n, PointsToNode::UnknownType, PointsToNode::UnknownEscape, false);
1928           // We are computing a raw address for a store captured
1929           // by an Initialize compute an appropriate address type.
1930           int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1931           assert(offs != Type::OffsetBot, "offset must be a constant");
1932         } else {
1933           _processed.set(n->_idx);
1934           return;
1935         }
1936       }
1937       break;
1938     }
1939     case Op_StorePConditional:
1940     case Op_CompareAndSwapP:
1941     case Op_CompareAndSwapN:
1942     {
1943       const Type *adr_type = phase->type(n->in(MemNode::Address));
1944       adr_type = adr_type->make_ptr();
1945       if (adr_type->isa_oopptr()) {
1946         add_node(n, PointsToNode::UnknownType, PointsToNode::UnknownEscape, false);
1947       } else {
1948         _processed.set(n->_idx);
1949         return;
1950       }
1951       break;
1952     }
1953     case Op_ThreadLocal:
1954     {
1955       add_node(n, PointsToNode::JavaObject, PointsToNode::ArgEscape, true);
1956       break;
1957     }
1958     default:
1959       ;
1960       // nothing to do
1961   }
1962   return;
1963 }
1964 
1965 void ConnectionGraph::build_connection_graph(Node *n, PhaseTransform *phase) {
1966   // Don't set processed bit for AddP, LoadP, StoreP since
1967   // they may need more then one pass to process.
1968   if (_processed.test(n->_idx))
1969     return; // No need to redefine node's state.
1970 
1971   PointsToNode *ptadr = ptnode_adr(n->_idx);
1972 
1973   if (n->is_Call()) {
1974     CallNode *call = n->as_Call();
1975     process_call_arguments(call, phase);
1976     _processed.set(n->_idx);
1977     return;
1978   }
1979 
1980   switch (n->Opcode()) {
1981     case Op_AddP:
1982     {
1983       Node *base = get_addp_base(n);
1984       // Create a field edge to this node from everything base could point to.
1985       VectorSet ptset(Thread::current()->resource_area());
1986       PointsTo(ptset, base, phase);
1987       for( VectorSetI i(&ptset); i.test(); ++i ) {
1988         uint pt = i.elem;
1989         add_field_edge(pt, n->_idx, address_offset(n, phase));
1990       }
1991       break;
1992     }
1993     case Op_CastX2P:
1994     {
1995       assert(false, "Op_CastX2P");
1996       break;
1997     }
1998     case Op_CastPP:
1999     case Op_CheckCastPP:
2000     case Op_EncodeP:
2001     case Op_DecodeN:
2002     {
2003       int ti = n->in(1)->_idx;
2004       if (_nodes->adr_at(ti)->node_type() == PointsToNode::JavaObject) {
2005         add_pointsto_edge(n->_idx, ti);
2006       } else {
2007         add_deferred_edge(n->_idx, ti);
2008       }
2009       _processed.set(n->_idx);
2010       break;
2011     }
2012     case Op_ConP:
2013     {
2014       assert(false, "Op_ConP");
2015       break;
2016     }
2017     case Op_ConN:
2018     {
2019       assert(false, "Op_ConN");
2020       break;
2021     }
2022     case Op_CreateEx:
2023     {
2024       assert(false, "Op_CreateEx");
2025       break;
2026     }
2027     case Op_LoadKlass:
2028     case Op_LoadNKlass:
2029     {
2030       assert(false, "Op_LoadKlass");
2031       break;
2032     }
2033     case Op_LoadP:
2034     case Op_LoadN:
2035     {
2036       const Type *t = phase->type(n);
2037 #ifdef ASSERT
2038       if (!t->isa_narrowoop() && t->isa_ptr() == NULL)
2039         assert(false, "Op_LoadP");
2040 #endif
2041 
2042       Node* adr = n->in(MemNode::Address)->uncast();
2043       const Type *adr_type = phase->type(adr);
2044       Node* adr_base;
2045       if (adr->is_AddP()) {
2046         adr_base = get_addp_base(adr);
2047       } else {
2048         adr_base = adr;
2049       }
2050 
2051       // For everything "adr_base" could point to, create a deferred edge from
2052       // this node to each field with the same offset.
2053       VectorSet ptset(Thread::current()->resource_area());
2054       PointsTo(ptset, adr_base, phase);
2055       int offset = address_offset(adr, phase);
2056       for( VectorSetI i(&ptset); i.test(); ++i ) {
2057         uint pt = i.elem;
2058         add_deferred_edge_to_fields(n->_idx, pt, offset);
2059       }
2060       break;
2061     }
2062     case Op_Parm:
2063     {
2064       assert(false, "Op_Parm");
2065       break;
2066     }
2067     case Op_Phi:
2068     {
2069 #ifdef ASSERT
2070       if (n->as_Phi()->type()->isa_ptr() == NULL)
2071         assert(false, "Op_Phi");
2072 #endif
2073       for (uint i = 1; i < n->req() ; i++) {
2074         Node* in = n->in(i);
2075         if (in == NULL)
2076           continue;  // ignore NULL
2077         in = in->uncast();
2078         if (in->is_top() || in == n)
2079           continue;  // ignore top or inputs which go back this node
2080         int ti = in->_idx;
2081         if (_nodes->adr_at(in->_idx)->node_type() == PointsToNode::JavaObject) {
2082           add_pointsto_edge(n->_idx, ti);
2083         } else {
2084           add_deferred_edge(n->_idx, ti);
2085         }
2086       }
2087       _processed.set(n->_idx);
2088       break;
2089     }
2090     case Op_Proj:
2091     {
2092       // we are only interested in the result projection from a call
2093       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() ) {
2094         process_call_result(n->as_Proj(), phase);
2095         assert(_processed.test(n->_idx), "all call results should be processed");
2096       } else {
2097         assert(false, "Op_Proj");
2098       }
2099       break;
2100     }
2101     case Op_Return:
2102     {
2103 #ifdef ASSERT
2104       if( n->req() <= TypeFunc::Parms ||
2105           !phase->type(n->in(TypeFunc::Parms))->isa_oopptr() ) {
2106         assert(false, "Op_Return");
2107       }
2108 #endif
2109       int ti = n->in(TypeFunc::Parms)->_idx;
2110       if (_nodes->adr_at(ti)->node_type() == PointsToNode::JavaObject) {
2111         add_pointsto_edge(n->_idx, ti);
2112       } else {
2113         add_deferred_edge(n->_idx, ti);
2114       }
2115       _processed.set(n->_idx);
2116       break;
2117     }
2118     case Op_StoreP:
2119     case Op_StoreN:
2120     case Op_StorePConditional:
2121     case Op_CompareAndSwapP:
2122     case Op_CompareAndSwapN:
2123     {
2124       Node *adr = n->in(MemNode::Address);
2125       const Type *adr_type = phase->type(adr)->make_ptr();
2126 #ifdef ASSERT
2127       if (!adr_type->isa_oopptr())
2128         assert(phase->type(adr) == TypeRawPtr::NOTNULL, "Op_StoreP");
2129 #endif
2130 
2131       assert(adr->is_AddP(), "expecting an AddP");
2132       Node *adr_base = get_addp_base(adr);
2133       Node *val = n->in(MemNode::ValueIn)->uncast();
2134       // For everything "adr_base" could point to, create a deferred edge
2135       // to "val" from each field with the same offset.
2136       VectorSet ptset(Thread::current()->resource_area());
2137       PointsTo(ptset, adr_base, phase);
2138       for( VectorSetI i(&ptset); i.test(); ++i ) {
2139         uint pt = i.elem;
2140         add_edge_from_fields(pt, val->_idx, address_offset(adr, phase));
2141       }
2142       break;
2143     }
2144     case Op_ThreadLocal:
2145     {
2146       assert(false, "Op_ThreadLocal");
2147       break;
2148     }
2149     default:
2150       ;
2151       // nothing to do
2152   }
2153 }
2154 
2155 #ifndef PRODUCT
2156 void ConnectionGraph::dump() {
2157   PhaseGVN  *igvn = _compile->initial_gvn();
2158   bool first = true;
2159 
2160   uint size = (uint)_nodes->length();
2161   for (uint ni = 0; ni < size; ni++) {
2162     PointsToNode *ptn = _nodes->adr_at(ni);
2163     PointsToNode::NodeType ptn_type = ptn->node_type();
2164 
2165     if (ptn_type != PointsToNode::JavaObject || ptn->_node == NULL)
2166       continue;
2167     PointsToNode::EscapeState es = escape_state(ptn->_node, igvn);
2168     if (ptn->_node->is_Allocate() && (es == PointsToNode::NoEscape || Verbose)) {
2169       if (first) {
2170         tty->cr();
2171         tty->print("======== Connection graph for ");
2172         C()->method()->print_short_name();
2173         tty->cr();
2174         first = false;
2175       }
2176       tty->print("%6d ", ni);
2177       ptn->dump();
2178       // Print all locals which reference this allocation
2179       for (uint li = ni; li < size; li++) {
2180         PointsToNode *ptn_loc = _nodes->adr_at(li);
2181         PointsToNode::NodeType ptn_loc_type = ptn_loc->node_type();
2182         if ( ptn_loc_type == PointsToNode::LocalVar && ptn_loc->_node != NULL &&
2183              ptn_loc->edge_count() == 1 && ptn_loc->edge_target(0) == ni ) {
2184           tty->print("%6d  LocalVar [[%d]]", li, ni);
2185           _nodes->adr_at(li)->_node->dump();
2186         }
2187       }
2188       if (Verbose) {
2189         // Print all fields which reference this allocation
2190         for (uint i = 0; i < ptn->edge_count(); i++) {
2191           uint ei = ptn->edge_target(i);
2192           tty->print("%6d  Field [[%d]]", ei, ni);
2193           _nodes->adr_at(ei)->_node->dump();
2194         }
2195       }
2196       tty->cr();
2197     }
2198   }
2199 }
2200 #endif