1 /*
   2  * Copyright (c) 1997, 2013, 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 "libadt/vectset.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "opto/cfgnode.hpp"
  29 #include "opto/connode.hpp"
  30 #include "opto/machnode.hpp"
  31 #include "opto/matcher.hpp"
  32 #include "opto/node.hpp"
  33 #include "opto/opcodes.hpp"
  34 #include "opto/regmask.hpp"
  35 #include "opto/type.hpp"
  36 #include "utilities/copy.hpp"
  37 
  38 class RegMask;
  39 // #include "phase.hpp"
  40 class PhaseTransform;
  41 class PhaseGVN;
  42 
  43 // Arena we are currently building Nodes in
  44 const uint Node::NotAMachineReg = 0xffff0000;
  45 
  46 #ifndef PRODUCT
  47 extern int nodes_created;
  48 #endif
  49 
  50 #ifdef ASSERT
  51 
  52 //-------------------------- construct_node------------------------------------
  53 // Set a breakpoint here to identify where a particular node index is built.
  54 void Node::verify_construction() {
  55   _debug_orig = NULL;
  56   int old_debug_idx = Compile::debug_idx();
  57   int new_debug_idx = old_debug_idx+1;
  58   if (new_debug_idx > 0) {
  59     // Arrange that the lowest five decimal digits of _debug_idx
  60     // will repeat those of _idx. In case this is somehow pathological,
  61     // we continue to assign negative numbers (!) consecutively.
  62     const int mod = 100000;
  63     int bump = (int)(_idx - new_debug_idx) % mod;
  64     if (bump < 0)  bump += mod;
  65     assert(bump >= 0 && bump < mod, "");
  66     new_debug_idx += bump;
  67   }
  68   Compile::set_debug_idx(new_debug_idx);
  69   set_debug_idx( new_debug_idx );
  70   assert(Compile::current()->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
  71   assert(Compile::current()->live_nodes() < (uint)MaxNodeLimit, "Live Node limit exceeded limit");
  72   if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (int)_idx == BreakAtNode)) {
  73     tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d", _idx, _debug_idx);
  74     BREAKPOINT;
  75   }
  76 #if OPTO_DU_ITERATOR_ASSERT
  77   _last_del = NULL;
  78   _del_tick = 0;
  79 #endif
  80   _hash_lock = 0;
  81 }
  82 
  83 
  84 // #ifdef ASSERT ...
  85 
  86 #if OPTO_DU_ITERATOR_ASSERT
  87 void DUIterator_Common::sample(const Node* node) {
  88   _vdui     = VerifyDUIterators;
  89   _node     = node;
  90   _outcnt   = node->_outcnt;
  91   _del_tick = node->_del_tick;
  92   _last     = NULL;
  93 }
  94 
  95 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
  96   assert(_node     == node, "consistent iterator source");
  97   assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
  98 }
  99 
 100 void DUIterator_Common::verify_resync() {
 101   // Ensure that the loop body has just deleted the last guy produced.
 102   const Node* node = _node;
 103   // Ensure that at least one copy of the last-seen edge was deleted.
 104   // Note:  It is OK to delete multiple copies of the last-seen edge.
 105   // Unfortunately, we have no way to verify that all the deletions delete
 106   // that same edge.  On this point we must use the Honor System.
 107   assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
 108   assert(node->_last_del == _last, "must have deleted the edge just produced");
 109   // We liked this deletion, so accept the resulting outcnt and tick.
 110   _outcnt   = node->_outcnt;
 111   _del_tick = node->_del_tick;
 112 }
 113 
 114 void DUIterator_Common::reset(const DUIterator_Common& that) {
 115   if (this == &that)  return;  // ignore assignment to self
 116   if (!_vdui) {
 117     // We need to initialize everything, overwriting garbage values.
 118     _last = that._last;
 119     _vdui = that._vdui;
 120   }
 121   // Note:  It is legal (though odd) for an iterator over some node x
 122   // to be reassigned to iterate over another node y.  Some doubly-nested
 123   // progress loops depend on being able to do this.
 124   const Node* node = that._node;
 125   // Re-initialize everything, except _last.
 126   _node     = node;
 127   _outcnt   = node->_outcnt;
 128   _del_tick = node->_del_tick;
 129 }
 130 
 131 void DUIterator::sample(const Node* node) {
 132   DUIterator_Common::sample(node);      // Initialize the assertion data.
 133   _refresh_tick = 0;                    // No refreshes have happened, as yet.
 134 }
 135 
 136 void DUIterator::verify(const Node* node, bool at_end_ok) {
 137   DUIterator_Common::verify(node, at_end_ok);
 138   assert(_idx      <  node->_outcnt + (uint)at_end_ok, "idx in range");
 139 }
 140 
 141 void DUIterator::verify_increment() {
 142   if (_refresh_tick & 1) {
 143     // We have refreshed the index during this loop.
 144     // Fix up _idx to meet asserts.
 145     if (_idx > _outcnt)  _idx = _outcnt;
 146   }
 147   verify(_node, true);
 148 }
 149 
 150 void DUIterator::verify_resync() {
 151   // Note:  We do not assert on _outcnt, because insertions are OK here.
 152   DUIterator_Common::verify_resync();
 153   // Make sure we are still in sync, possibly with no more out-edges:
 154   verify(_node, true);
 155 }
 156 
 157 void DUIterator::reset(const DUIterator& that) {
 158   if (this == &that)  return;  // self assignment is always a no-op
 159   assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
 160   assert(that._idx          == 0, "assign only the result of Node::outs()");
 161   assert(_idx               == that._idx, "already assigned _idx");
 162   if (!_vdui) {
 163     // We need to initialize everything, overwriting garbage values.
 164     sample(that._node);
 165   } else {
 166     DUIterator_Common::reset(that);
 167     if (_refresh_tick & 1) {
 168       _refresh_tick++;                  // Clear the "was refreshed" flag.
 169     }
 170     assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
 171   }
 172 }
 173 
 174 void DUIterator::refresh() {
 175   DUIterator_Common::sample(_node);     // Re-fetch assertion data.
 176   _refresh_tick |= 1;                   // Set the "was refreshed" flag.
 177 }
 178 
 179 void DUIterator::verify_finish() {
 180   // If the loop has killed the node, do not require it to re-run.
 181   if (_node->_outcnt == 0)  _refresh_tick &= ~1;
 182   // If this assert triggers, it means that a loop used refresh_out_pos
 183   // to re-synch an iteration index, but the loop did not correctly
 184   // re-run itself, using a "while (progress)" construct.
 185   // This iterator enforces the rule that you must keep trying the loop
 186   // until it "runs clean" without any need for refreshing.
 187   assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
 188 }
 189 
 190 
 191 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
 192   DUIterator_Common::verify(node, at_end_ok);
 193   Node** out    = node->_out;
 194   uint   cnt    = node->_outcnt;
 195   assert(cnt == _outcnt, "no insertions allowed");
 196   assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
 197   // This last check is carefully designed to work for NO_OUT_ARRAY.
 198 }
 199 
 200 void DUIterator_Fast::verify_limit() {
 201   const Node* node = _node;
 202   verify(node, true);
 203   assert(_outp == node->_out + node->_outcnt, "limit still correct");
 204 }
 205 
 206 void DUIterator_Fast::verify_resync() {
 207   const Node* node = _node;
 208   if (_outp == node->_out + _outcnt) {
 209     // Note that the limit imax, not the pointer i, gets updated with the
 210     // exact count of deletions.  (For the pointer it's always "--i".)
 211     assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
 212     // This is a limit pointer, with a name like "imax".
 213     // Fudge the _last field so that the common assert will be happy.
 214     _last = (Node*) node->_last_del;
 215     DUIterator_Common::verify_resync();
 216   } else {
 217     assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
 218     // A normal internal pointer.
 219     DUIterator_Common::verify_resync();
 220     // Make sure we are still in sync, possibly with no more out-edges:
 221     verify(node, true);
 222   }
 223 }
 224 
 225 void DUIterator_Fast::verify_relimit(uint n) {
 226   const Node* node = _node;
 227   assert((int)n > 0, "use imax -= n only with a positive count");
 228   // This must be a limit pointer, with a name like "imax".
 229   assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
 230   // The reported number of deletions must match what the node saw.
 231   assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
 232   // Fudge the _last field so that the common assert will be happy.
 233   _last = (Node*) node->_last_del;
 234   DUIterator_Common::verify_resync();
 235 }
 236 
 237 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
 238   assert(_outp              == that._outp, "already assigned _outp");
 239   DUIterator_Common::reset(that);
 240 }
 241 
 242 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
 243   // at_end_ok means the _outp is allowed to underflow by 1
 244   _outp += at_end_ok;
 245   DUIterator_Fast::verify(node, at_end_ok);  // check _del_tick, etc.
 246   _outp -= at_end_ok;
 247   assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
 248 }
 249 
 250 void DUIterator_Last::verify_limit() {
 251   // Do not require the limit address to be resynched.
 252   //verify(node, true);
 253   assert(_outp == _node->_out, "limit still correct");
 254 }
 255 
 256 void DUIterator_Last::verify_step(uint num_edges) {
 257   assert((int)num_edges > 0, "need non-zero edge count for loop progress");
 258   _outcnt   -= num_edges;
 259   _del_tick += num_edges;
 260   // Make sure we are still in sync, possibly with no more out-edges:
 261   const Node* node = _node;
 262   verify(node, true);
 263   assert(node->_last_del == _last, "must have deleted the edge just produced");
 264 }
 265 
 266 #endif //OPTO_DU_ITERATOR_ASSERT
 267 
 268 
 269 #endif //ASSERT
 270 
 271 
 272 // This constant used to initialize _out may be any non-null value.
 273 // The value NULL is reserved for the top node only.
 274 #define NO_OUT_ARRAY ((Node**)-1)
 275 
 276 // This funny expression handshakes with Node::operator new
 277 // to pull Compile::current out of the new node's _out field,
 278 // and then calls a subroutine which manages most field
 279 // initializations.  The only one which is tricky is the
 280 // _idx field, which is const, and so must be initialized
 281 // by a return value, not an assignment.
 282 //
 283 // (Aren't you thankful that Java finals don't require so many tricks?)
 284 #define IDX_INIT(req) this->Init((req), (Compile*) this->_out)
 285 #ifdef _MSC_VER // the IDX_INIT hack falls foul of warning C4355
 286 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
 287 #endif
 288 #ifdef __clang__
 289 #pragma clang diagnostic push
 290 #pragma GCC diagnostic ignored "-Wuninitialized"
 291 #endif
 292 
 293 // Out-of-line code from node constructors.
 294 // Executed only when extra debug info. is being passed around.
 295 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
 296   C->set_node_notes_at(idx, nn);
 297 }
 298 
 299 // Shared initialization code.
 300 inline int Node::Init(int req, Compile* C) {
 301   assert(Compile::current() == C, "must use operator new(Compile*)");
 302   int idx = C->next_unique();
 303 
 304   // Allocate memory for the necessary number of edges.
 305   if (req > 0) {
 306     // Allocate space for _in array to have double alignment.
 307     _in = (Node **) ((char *) (C->node_arena()->Amalloc_D(req * sizeof(void*))));
 308 #ifdef ASSERT
 309     _in[req-1] = this; // magic cookie for assertion check
 310 #endif
 311   }
 312   // If there are default notes floating around, capture them:
 313   Node_Notes* nn = C->default_node_notes();
 314   if (nn != NULL)  init_node_notes(C, idx, nn);
 315 
 316   // Note:  At this point, C is dead,
 317   // and we begin to initialize the new Node.
 318 
 319   _cnt = _max = req;
 320   _outcnt = _outmax = 0;
 321   _class_id = Class_Node;
 322   _flags = 0;
 323   _out = NO_OUT_ARRAY;
 324   return idx;
 325 }
 326 
 327 //------------------------------Node-------------------------------------------
 328 // Create a Node, with a given number of required edges.
 329 Node::Node(uint req)
 330   : _idx(IDX_INIT(req))
 331 {
 332   assert( req < (uint)(MaxNodeLimit - NodeLimitFudgeFactor), "Input limit exceeded" );
 333   debug_only( verify_construction() );
 334   NOT_PRODUCT(nodes_created++);
 335   if (req == 0) {
 336     assert( _in == (Node**)this, "Must not pass arg count to 'new'" );
 337     _in = NULL;
 338   } else {
 339     assert( _in[req-1] == this, "Must pass arg count to 'new'" );
 340     Node** to = _in;
 341     for(uint i = 0; i < req; i++) {
 342       to[i] = NULL;
 343     }
 344   }
 345 }
 346 
 347 //------------------------------Node-------------------------------------------
 348 Node::Node(Node *n0)
 349   : _idx(IDX_INIT(1))
 350 {
 351   debug_only( verify_construction() );
 352   NOT_PRODUCT(nodes_created++);
 353   // Assert we allocated space for input array already
 354   assert( _in[0] == this, "Must pass arg count to 'new'" );
 355   assert( is_not_dead(n0), "can not use dead node");
 356   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 357 }
 358 
 359 //------------------------------Node-------------------------------------------
 360 Node::Node(Node *n0, Node *n1)
 361   : _idx(IDX_INIT(2))
 362 {
 363   debug_only( verify_construction() );
 364   NOT_PRODUCT(nodes_created++);
 365   // Assert we allocated space for input array already
 366   assert( _in[1] == this, "Must pass arg count to 'new'" );
 367   assert( is_not_dead(n0), "can not use dead node");
 368   assert( is_not_dead(n1), "can not use dead node");
 369   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 370   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 371 }
 372 
 373 //------------------------------Node-------------------------------------------
 374 Node::Node(Node *n0, Node *n1, Node *n2)
 375   : _idx(IDX_INIT(3))
 376 {
 377   debug_only( verify_construction() );
 378   NOT_PRODUCT(nodes_created++);
 379   // Assert we allocated space for input array already
 380   assert( _in[2] == this, "Must pass arg count to 'new'" );
 381   assert( is_not_dead(n0), "can not use dead node");
 382   assert( is_not_dead(n1), "can not use dead node");
 383   assert( is_not_dead(n2), "can not use dead node");
 384   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 385   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 386   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 387 }
 388 
 389 //------------------------------Node-------------------------------------------
 390 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
 391   : _idx(IDX_INIT(4))
 392 {
 393   debug_only( verify_construction() );
 394   NOT_PRODUCT(nodes_created++);
 395   // Assert we allocated space for input array already
 396   assert( _in[3] == this, "Must pass arg count to 'new'" );
 397   assert( is_not_dead(n0), "can not use dead node");
 398   assert( is_not_dead(n1), "can not use dead node");
 399   assert( is_not_dead(n2), "can not use dead node");
 400   assert( is_not_dead(n3), "can not use dead node");
 401   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 402   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 403   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 404   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 405 }
 406 
 407 //------------------------------Node-------------------------------------------
 408 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
 409   : _idx(IDX_INIT(5))
 410 {
 411   debug_only( verify_construction() );
 412   NOT_PRODUCT(nodes_created++);
 413   // Assert we allocated space for input array already
 414   assert( _in[4] == this, "Must pass arg count to 'new'" );
 415   assert( is_not_dead(n0), "can not use dead node");
 416   assert( is_not_dead(n1), "can not use dead node");
 417   assert( is_not_dead(n2), "can not use dead node");
 418   assert( is_not_dead(n3), "can not use dead node");
 419   assert( is_not_dead(n4), "can not use dead node");
 420   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 421   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 422   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 423   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 424   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 425 }
 426 
 427 //------------------------------Node-------------------------------------------
 428 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
 429                      Node *n4, Node *n5)
 430   : _idx(IDX_INIT(6))
 431 {
 432   debug_only( verify_construction() );
 433   NOT_PRODUCT(nodes_created++);
 434   // Assert we allocated space for input array already
 435   assert( _in[5] == this, "Must pass arg count to 'new'" );
 436   assert( is_not_dead(n0), "can not use dead node");
 437   assert( is_not_dead(n1), "can not use dead node");
 438   assert( is_not_dead(n2), "can not use dead node");
 439   assert( is_not_dead(n3), "can not use dead node");
 440   assert( is_not_dead(n4), "can not use dead node");
 441   assert( is_not_dead(n5), "can not use dead node");
 442   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 443   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 444   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 445   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 446   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 447   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
 448 }
 449 
 450 //------------------------------Node-------------------------------------------
 451 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
 452                      Node *n4, Node *n5, Node *n6)
 453   : _idx(IDX_INIT(7))
 454 {
 455   debug_only( verify_construction() );
 456   NOT_PRODUCT(nodes_created++);
 457   // Assert we allocated space for input array already
 458   assert( _in[6] == this, "Must pass arg count to 'new'" );
 459   assert( is_not_dead(n0), "can not use dead node");
 460   assert( is_not_dead(n1), "can not use dead node");
 461   assert( is_not_dead(n2), "can not use dead node");
 462   assert( is_not_dead(n3), "can not use dead node");
 463   assert( is_not_dead(n4), "can not use dead node");
 464   assert( is_not_dead(n5), "can not use dead node");
 465   assert( is_not_dead(n6), "can not use dead node");
 466   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 467   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 468   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 469   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 470   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 471   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
 472   _in[6] = n6; if (n6 != NULL) n6->add_out((Node *)this);
 473 }
 474 
 475 #ifdef __clang__
 476 #pragma clang diagnostic pop
 477 #endif
 478 
 479 
 480 //------------------------------clone------------------------------------------
 481 // Clone a Node.
 482 Node *Node::clone() const {
 483   Compile* C = Compile::current();
 484   uint s = size_of();           // Size of inherited Node
 485   Node *n = (Node*)C->node_arena()->Amalloc_D(size_of() + _max*sizeof(Node*));
 486   Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
 487   // Set the new input pointer array
 488   n->_in = (Node**)(((char*)n)+s);
 489   // Cannot share the old output pointer array, so kill it
 490   n->_out = NO_OUT_ARRAY;
 491   // And reset the counters to 0
 492   n->_outcnt = 0;
 493   n->_outmax = 0;
 494   // Unlock this guy, since he is not in any hash table.
 495   debug_only(n->_hash_lock = 0);
 496   // Walk the old node's input list to duplicate its edges
 497   uint i;
 498   for( i = 0; i < len(); i++ ) {
 499     Node *x = in(i);
 500     n->_in[i] = x;
 501     if (x != NULL) x->add_out(n);
 502   }
 503   if (is_macro())
 504     C->add_macro_node(n);
 505   if (is_expensive())
 506     C->add_expensive_node(n);
 507 
 508   n->set_idx(C->next_unique()); // Get new unique index as well
 509   debug_only( n->verify_construction() );
 510   NOT_PRODUCT(nodes_created++);
 511   // Do not patch over the debug_idx of a clone, because it makes it
 512   // impossible to break on the clone's moment of creation.
 513   //debug_only( n->set_debug_idx( debug_idx() ) );
 514 
 515   C->copy_node_notes_to(n, (Node*) this);
 516 
 517   // MachNode clone
 518   uint nopnds;
 519   if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
 520     MachNode *mach  = n->as_Mach();
 521     MachNode *mthis = this->as_Mach();
 522     // Get address of _opnd_array.
 523     // It should be the same offset since it is the clone of this node.
 524     MachOper **from = mthis->_opnds;
 525     MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
 526                     pointer_delta((const void*)from,
 527                                   (const void*)(&mthis->_opnds), 1));
 528     mach->_opnds = to;
 529     for ( uint i = 0; i < nopnds; ++i ) {
 530       to[i] = from[i]->clone(C);
 531     }
 532   }
 533   // cloning CallNode may need to clone JVMState
 534   if (n->is_Call()) {
 535     n->as_Call()->clone_jvms(C);
 536   }
 537   return n;                     // Return the clone
 538 }
 539 
 540 //---------------------------setup_is_top--------------------------------------
 541 // Call this when changing the top node, to reassert the invariants
 542 // required by Node::is_top.  See Compile::set_cached_top_node.
 543 void Node::setup_is_top() {
 544   if (this == (Node*)Compile::current()->top()) {
 545     // This node has just become top.  Kill its out array.
 546     _outcnt = _outmax = 0;
 547     _out = NULL;                           // marker value for top
 548     assert(is_top(), "must be top");
 549   } else {
 550     if (_out == NULL)  _out = NO_OUT_ARRAY;
 551     assert(!is_top(), "must not be top");
 552   }
 553 }
 554 
 555 
 556 //------------------------------~Node------------------------------------------
 557 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 558 extern int reclaim_idx ;
 559 extern int reclaim_in  ;
 560 extern int reclaim_node;
 561 void Node::destruct() {
 562   // Eagerly reclaim unique Node numberings
 563   Compile* compile = Compile::current();
 564   if ((uint)_idx+1 == compile->unique()) {
 565     compile->set_unique(compile->unique()-1);
 566 #ifdef ASSERT
 567     reclaim_idx++;
 568 #endif
 569   }
 570   // Clear debug info:
 571   Node_Notes* nn = compile->node_notes_at(_idx);
 572   if (nn != NULL)  nn->clear();
 573   // Walk the input array, freeing the corresponding output edges
 574   _cnt = _max;  // forget req/prec distinction
 575   uint i;
 576   for( i = 0; i < _max; i++ ) {
 577     set_req(i, NULL);
 578     //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
 579   }
 580   assert(outcnt() == 0, "deleting a node must not leave a dangling use");
 581   // See if the input array was allocated just prior to the object
 582   int edge_size = _max*sizeof(void*);
 583   int out_edge_size = _outmax*sizeof(void*);
 584   char *edge_end = ((char*)_in) + edge_size;
 585   char *out_array = (char*)(_out == NO_OUT_ARRAY? NULL: _out);
 586   char *out_edge_end = out_array + out_edge_size;
 587   int node_size = size_of();
 588 
 589   // Free the output edge array
 590   if (out_edge_size > 0) {
 591 #ifdef ASSERT
 592     if( out_edge_end == compile->node_arena()->hwm() )
 593       reclaim_in  += out_edge_size;  // count reclaimed out edges with in edges
 594 #endif
 595     compile->node_arena()->Afree(out_array, out_edge_size);
 596   }
 597 
 598   // Free the input edge array and the node itself
 599   if( edge_end == (char*)this ) {
 600 #ifdef ASSERT
 601     if( edge_end+node_size == compile->node_arena()->hwm() ) {
 602       reclaim_in  += edge_size;
 603       reclaim_node+= node_size;
 604     }
 605 #else
 606     // It was; free the input array and object all in one hit
 607     compile->node_arena()->Afree(_in,edge_size+node_size);
 608 #endif
 609   } else {
 610 
 611     // Free just the input array
 612 #ifdef ASSERT
 613     if( edge_end == compile->node_arena()->hwm() )
 614       reclaim_in  += edge_size;
 615 #endif
 616     compile->node_arena()->Afree(_in,edge_size);
 617 
 618     // Free just the object
 619 #ifdef ASSERT
 620     if( ((char*)this) + node_size == compile->node_arena()->hwm() )
 621       reclaim_node+= node_size;
 622 #else
 623     compile->node_arena()->Afree(this,node_size);
 624 #endif
 625   }
 626   if (is_macro()) {
 627     compile->remove_macro_node(this);
 628   }
 629   if (is_expensive()) {
 630     compile->remove_expensive_node(this);
 631   }
 632 #ifdef ASSERT
 633   // We will not actually delete the storage, but we'll make the node unusable.
 634   *(address*)this = badAddress;  // smash the C++ vtbl, probably
 635   _in = _out = (Node**) badAddress;
 636   _max = _cnt = _outmax = _outcnt = 0;
 637 #endif
 638 }
 639 
 640 //------------------------------grow-------------------------------------------
 641 // Grow the input array, making space for more edges
 642 void Node::grow( uint len ) {
 643   Arena* arena = Compile::current()->node_arena();
 644   uint new_max = _max;
 645   if( new_max == 0 ) {
 646     _max = 4;
 647     _in = (Node**)arena->Amalloc(4*sizeof(Node*));
 648     Node** to = _in;
 649     to[0] = NULL;
 650     to[1] = NULL;
 651     to[2] = NULL;
 652     to[3] = NULL;
 653     return;
 654   }
 655   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
 656   // Trimming to limit allows a uint8 to handle up to 255 edges.
 657   // Previously I was using only powers-of-2 which peaked at 128 edges.
 658   //if( new_max >= limit ) new_max = limit-1;
 659   _in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
 660   Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // NULL all new space
 661   _max = new_max;               // Record new max length
 662   // This assertion makes sure that Node::_max is wide enough to
 663   // represent the numerical value of new_max.
 664   assert(_max == new_max && _max > len, "int width of _max is too small");
 665 }
 666 
 667 //-----------------------------out_grow----------------------------------------
 668 // Grow the input array, making space for more edges
 669 void Node::out_grow( uint len ) {
 670   assert(!is_top(), "cannot grow a top node's out array");
 671   Arena* arena = Compile::current()->node_arena();
 672   uint new_max = _outmax;
 673   if( new_max == 0 ) {
 674     _outmax = 4;
 675     _out = (Node **)arena->Amalloc(4*sizeof(Node*));
 676     return;
 677   }
 678   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
 679   // Trimming to limit allows a uint8 to handle up to 255 edges.
 680   // Previously I was using only powers-of-2 which peaked at 128 edges.
 681   //if( new_max >= limit ) new_max = limit-1;
 682   assert(_out != NULL && _out != NO_OUT_ARRAY, "out must have sensible value");
 683   _out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
 684   //Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // NULL all new space
 685   _outmax = new_max;               // Record new max length
 686   // This assertion makes sure that Node::_max is wide enough to
 687   // represent the numerical value of new_max.
 688   assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
 689 }
 690 
 691 #ifdef ASSERT
 692 //------------------------------is_dead----------------------------------------
 693 bool Node::is_dead() const {
 694   // Mach and pinch point nodes may look like dead.
 695   if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
 696     return false;
 697   for( uint i = 0; i < _max; i++ )
 698     if( _in[i] != NULL )
 699       return false;
 700   dump();
 701   return true;
 702 }
 703 #endif
 704 
 705 
 706 //------------------------------is_unreachable---------------------------------
 707 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
 708   assert(!is_Mach(), "doesn't work with MachNodes");
 709   return outcnt() == 0 || igvn.type(this) == Type::TOP || in(0)->is_top();
 710 }
 711 
 712 //------------------------------add_req----------------------------------------
 713 // Add a new required input at the end
 714 void Node::add_req( Node *n ) {
 715   assert( is_not_dead(n), "can not use dead node");
 716 
 717   // Look to see if I can move precedence down one without reallocating
 718   if( (_cnt >= _max) || (in(_max-1) != NULL) )
 719     grow( _max+1 );
 720 
 721   // Find a precedence edge to move
 722   if( in(_cnt) != NULL ) {       // Next precedence edge is busy?
 723     uint i;
 724     for( i=_cnt; i<_max; i++ )
 725       if( in(i) == NULL )       // Find the NULL at end of prec edge list
 726         break;                  // There must be one, since we grew the array
 727     _in[i] = in(_cnt);          // Move prec over, making space for req edge
 728   }
 729   _in[_cnt++] = n;            // Stuff over old prec edge
 730   if (n != NULL) n->add_out((Node *)this);
 731 }
 732 
 733 //---------------------------add_req_batch-------------------------------------
 734 // Add a new required input at the end
 735 void Node::add_req_batch( Node *n, uint m ) {
 736   assert( is_not_dead(n), "can not use dead node");
 737   // check various edge cases
 738   if ((int)m <= 1) {
 739     assert((int)m >= 0, "oob");
 740     if (m != 0)  add_req(n);
 741     return;
 742   }
 743 
 744   // Look to see if I can move precedence down one without reallocating
 745   if( (_cnt+m) > _max || _in[_max-m] )
 746     grow( _max+m );
 747 
 748   // Find a precedence edge to move
 749   if( _in[_cnt] != NULL ) {     // Next precedence edge is busy?
 750     uint i;
 751     for( i=_cnt; i<_max; i++ )
 752       if( _in[i] == NULL )      // Find the NULL at end of prec edge list
 753         break;                  // There must be one, since we grew the array
 754     // Slide all the precs over by m positions (assume #prec << m).
 755     Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
 756   }
 757 
 758   // Stuff over the old prec edges
 759   for(uint i=0; i<m; i++ ) {
 760     _in[_cnt++] = n;
 761   }
 762 
 763   // Insert multiple out edges on the node.
 764   if (n != NULL && !n->is_top()) {
 765     for(uint i=0; i<m; i++ ) {
 766       n->add_out((Node *)this);
 767     }
 768   }
 769 }
 770 
 771 //------------------------------del_req----------------------------------------
 772 // Delete the required edge and compact the edge array
 773 void Node::del_req( uint idx ) {
 774   assert( idx < _cnt, "oob");
 775   assert( !VerifyHashTableKeys || _hash_lock == 0,
 776           "remove node from hash table before modifying it");
 777   // First remove corresponding def-use edge
 778   Node *n = in(idx);
 779   if (n != NULL) n->del_out((Node *)this);
 780   _in[idx] = in(--_cnt);  // Compact the array
 781   _in[_cnt] = NULL;       // NULL out emptied slot
 782 }
 783 
 784 //------------------------------del_req_ordered--------------------------------
 785 // Delete the required edge and compact the edge array with preserved order
 786 void Node::del_req_ordered( uint idx ) {
 787   assert( idx < _cnt, "oob");
 788   assert( !VerifyHashTableKeys || _hash_lock == 0,
 789           "remove node from hash table before modifying it");
 790   // First remove corresponding def-use edge
 791   Node *n = in(idx);
 792   if (n != NULL) n->del_out((Node *)this);
 793   if (idx < _cnt - 1) { // Not last edge ?
 794     Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx-1)*sizeof(Node*)));
 795   }
 796   _in[--_cnt] = NULL;   // NULL out emptied slot
 797 }
 798 
 799 //------------------------------ins_req----------------------------------------
 800 // Insert a new required input at the end
 801 void Node::ins_req( uint idx, Node *n ) {
 802   assert( is_not_dead(n), "can not use dead node");
 803   add_req(NULL);                // Make space
 804   assert( idx < _max, "Must have allocated enough space");
 805   // Slide over
 806   if(_cnt-idx-1 > 0) {
 807     Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
 808   }
 809   _in[idx] = n;                            // Stuff over old required edge
 810   if (n != NULL) n->add_out((Node *)this); // Add reciprocal def-use edge
 811 }
 812 
 813 //-----------------------------find_edge---------------------------------------
 814 int Node::find_edge(Node* n) {
 815   for (uint i = 0; i < len(); i++) {
 816     if (_in[i] == n)  return i;
 817   }
 818   return -1;
 819 }
 820 
 821 //----------------------------replace_edge-------------------------------------
 822 int Node::replace_edge(Node* old, Node* neww) {
 823   if (old == neww)  return 0;  // nothing to do
 824   uint nrep = 0;
 825   for (uint i = 0; i < len(); i++) {
 826     if (in(i) == old) {
 827       if (i < req())
 828         set_req(i, neww);
 829       else
 830         set_prec(i, neww);
 831       nrep++;
 832     }
 833   }
 834   return nrep;
 835 }
 836 
 837 /**
 838  * Replace input edges in the range pointing to 'old' node.
 839  */
 840 int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end) {
 841   if (old == neww)  return 0;  // nothing to do
 842   uint nrep = 0;
 843   for (int i = start; i < end; i++) {
 844     if (in(i) == old) {
 845       set_req(i, neww);
 846       nrep++;
 847     }
 848   }
 849   return nrep;
 850 }
 851 
 852 //-------------------------disconnect_inputs-----------------------------------
 853 // NULL out all inputs to eliminate incoming Def-Use edges.
 854 // Return the number of edges between 'n' and 'this'
 855 int Node::disconnect_inputs(Node *n, Compile* C) {
 856   int edges_to_n = 0;
 857 
 858   uint cnt = req();
 859   for( uint i = 0; i < cnt; ++i ) {
 860     if( in(i) == 0 ) continue;
 861     if( in(i) == n ) ++edges_to_n;
 862     set_req(i, NULL);
 863   }
 864   // Remove precedence edges if any exist
 865   // Note: Safepoints may have precedence edges, even during parsing
 866   if( (req() != len()) && (in(req()) != NULL) ) {
 867     uint max = len();
 868     for( uint i = 0; i < max; ++i ) {
 869       if( in(i) == 0 ) continue;
 870       if( in(i) == n ) ++edges_to_n;
 871       set_prec(i, NULL);
 872     }
 873   }
 874 
 875   // Node::destruct requires all out edges be deleted first
 876   // debug_only(destruct();)   // no reuse benefit expected
 877   if (edges_to_n == 0) {
 878     C->record_dead_node(_idx);
 879   }
 880   return edges_to_n;
 881 }
 882 
 883 //-----------------------------uncast---------------------------------------
 884 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
 885 // Strip away casting.  (It is depth-limited.)
 886 Node* Node::uncast() const {
 887   // Should be inline:
 888   //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
 889   if (is_ConstraintCast() || is_CheckCastPP())
 890     return uncast_helper(this);
 891   else
 892     return (Node*) this;
 893 }
 894 
 895 //---------------------------uncast_helper-------------------------------------
 896 Node* Node::uncast_helper(const Node* p) {
 897 #ifdef ASSERT
 898   uint depth_count = 0;
 899   const Node* orig_p = p;
 900 #endif
 901 
 902   while (true) {
 903 #ifdef ASSERT
 904     if (depth_count >= K) {
 905       orig_p->dump(4);
 906       if (p != orig_p)
 907         p->dump(1);
 908     }
 909     assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
 910 #endif
 911     if (p == NULL || p->req() != 2) {
 912       break;
 913     } else if (p->is_ConstraintCast()) {
 914       p = p->in(1);
 915     } else if (p->is_CheckCastPP()) {
 916       p = p->in(1);
 917     } else {
 918       break;
 919     }
 920   }
 921   return (Node*) p;
 922 }
 923 
 924 //------------------------------add_prec---------------------------------------
 925 // Add a new precedence input.  Precedence inputs are unordered, with
 926 // duplicates removed and NULLs packed down at the end.
 927 void Node::add_prec( Node *n ) {
 928   assert( is_not_dead(n), "can not use dead node");
 929 
 930   // Check for NULL at end
 931   if( _cnt >= _max || in(_max-1) )
 932     grow( _max+1 );
 933 
 934   // Find a precedence edge to move
 935   uint i = _cnt;
 936   while( in(i) != NULL ) i++;
 937   _in[i] = n;                                // Stuff prec edge over NULL
 938   if ( n != NULL) n->add_out((Node *)this);  // Add mirror edge
 939 }
 940 
 941 //------------------------------rm_prec----------------------------------------
 942 // Remove a precedence input.  Precedence inputs are unordered, with
 943 // duplicates removed and NULLs packed down at the end.
 944 void Node::rm_prec( uint j ) {
 945 
 946   // Find end of precedence list to pack NULLs
 947   uint i;
 948   for( i=j; i<_max; i++ )
 949     if( !_in[i] )               // Find the NULL at end of prec edge list
 950       break;
 951   if (_in[j] != NULL) _in[j]->del_out((Node *)this);
 952   _in[j] = _in[--i];            // Move last element over removed guy
 953   _in[i] = NULL;                // NULL out last element
 954 }
 955 
 956 //------------------------------size_of----------------------------------------
 957 uint Node::size_of() const { return sizeof(*this); }
 958 
 959 //------------------------------ideal_reg--------------------------------------
 960 uint Node::ideal_reg() const { return 0; }
 961 
 962 //------------------------------jvms-------------------------------------------
 963 JVMState* Node::jvms() const { return NULL; }
 964 
 965 #ifdef ASSERT
 966 //------------------------------jvms-------------------------------------------
 967 bool Node::verify_jvms(const JVMState* using_jvms) const {
 968   for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
 969     if (jvms == using_jvms)  return true;
 970   }
 971   return false;
 972 }
 973 
 974 //------------------------------init_NodeProperty------------------------------
 975 void Node::init_NodeProperty() {
 976   assert(_max_classes <= max_jushort, "too many NodeProperty classes");
 977   assert(_max_flags <= max_jushort, "too many NodeProperty flags");
 978 }
 979 #endif
 980 
 981 //------------------------------format-----------------------------------------
 982 // Print as assembly
 983 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
 984 //------------------------------emit-------------------------------------------
 985 // Emit bytes starting at parameter 'ptr'.
 986 void Node::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {}
 987 //------------------------------size-------------------------------------------
 988 // Size of instruction in bytes
 989 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
 990 
 991 //------------------------------CFG Construction-------------------------------
 992 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
 993 // Goto and Return.
 994 const Node *Node::is_block_proj() const { return 0; }
 995 
 996 // Minimum guaranteed type
 997 const Type *Node::bottom_type() const { return Type::BOTTOM; }
 998 
 999 
1000 //------------------------------raise_bottom_type------------------------------
1001 // Get the worst-case Type output for this Node.
1002 void Node::raise_bottom_type(const Type* new_type) {
1003   if (is_Type()) {
1004     TypeNode *n = this->as_Type();
1005     if (VerifyAliases) {
1006       assert(new_type->higher_equal(n->type()), "new type must refine old type");
1007     }
1008     n->set_type(new_type);
1009   } else if (is_Load()) {
1010     LoadNode *n = this->as_Load();
1011     if (VerifyAliases) {
1012       assert(new_type->higher_equal(n->type()), "new type must refine old type");
1013     }
1014     n->set_type(new_type);
1015   }
1016 }
1017 
1018 //------------------------------Identity---------------------------------------
1019 // Return a node that the given node is equivalent to.
1020 Node *Node::Identity( PhaseTransform * ) {
1021   return this;                  // Default to no identities
1022 }
1023 
1024 //------------------------------Value------------------------------------------
1025 // Compute a new Type for a node using the Type of the inputs.
1026 const Type *Node::Value( PhaseTransform * ) const {
1027   return bottom_type();         // Default to worst-case Type
1028 }
1029 
1030 //------------------------------Ideal------------------------------------------
1031 //
1032 // 'Idealize' the graph rooted at this Node.
1033 //
1034 // In order to be efficient and flexible there are some subtle invariants
1035 // these Ideal calls need to hold.  Running with '+VerifyIterativeGVN' checks
1036 // these invariants, although its too slow to have on by default.  If you are
1037 // hacking an Ideal call, be sure to test with +VerifyIterativeGVN!
1038 //
1039 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1040 // pointer.  If ANY change is made, it must return the root of the reshaped
1041 // graph - even if the root is the same Node.  Example: swapping the inputs
1042 // to an AddINode gives the same answer and same root, but you still have to
1043 // return the 'this' pointer instead of NULL.
1044 //
1045 // You cannot return an OLD Node, except for the 'this' pointer.  Use the
1046 // Identity call to return an old Node; basically if Identity can find
1047 // another Node have the Ideal call make no change and return NULL.
1048 // Example: AddINode::Ideal must check for add of zero; in this case it
1049 // returns NULL instead of doing any graph reshaping.
1050 //
1051 // You cannot modify any old Nodes except for the 'this' pointer.  Due to
1052 // sharing there may be other users of the old Nodes relying on their current
1053 // semantics.  Modifying them will break the other users.
1054 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1055 // "X+3" unchanged in case it is shared.
1056 //
1057 // If you modify the 'this' pointer's inputs, you should use
1058 // 'set_req'.  If you are making a new Node (either as the new root or
1059 // some new internal piece) you may use 'init_req' to set the initial
1060 // value.  You can make a new Node with either 'new' or 'clone'.  In
1061 // either case, def-use info is correctly maintained.
1062 //
1063 // Example: reshape "(X+3)+4" into "X+7":
1064 //    set_req(1, in(1)->in(1));
1065 //    set_req(2, phase->intcon(7));
1066 //    return this;
1067 // Example: reshape "X*4" into "X<<2"
1068 //    return new (C) LShiftINode(in(1), phase->intcon(2));
1069 //
1070 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1071 // for the returned root node.  Example: reshape "X*31" with "(X<<5)-X".
1072 //    Node *shift=phase->transform(new(C)LShiftINode(in(1),phase->intcon(5)));
1073 //    return new (C) AddINode(shift, in(1));
1074 //
1075 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1076 // These forms are faster than 'phase->transform(new (C) ConNode())' and Do
1077 // The Right Thing with def-use info.
1078 //
1079 // You cannot bury the 'this' Node inside of a graph reshape.  If the reshaped
1080 // graph uses the 'this' Node it must be the root.  If you want a Node with
1081 // the same Opcode as the 'this' pointer use 'clone'.
1082 //
1083 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1084   return NULL;                  // Default to being Ideal already
1085 }
1086 
1087 // Some nodes have specific Ideal subgraph transformations only if they are
1088 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1089 // for the transformations to happen.
1090 bool Node::has_special_unique_user() const {
1091   assert(outcnt() == 1, "match only for unique out");
1092   Node* n = unique_out();
1093   int op  = Opcode();
1094   if( this->is_Store() ) {
1095     // Condition for back-to-back stores folding.
1096     return n->Opcode() == op && n->in(MemNode::Memory) == this;
1097   } else if( op == Op_AddL ) {
1098     // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1099     return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1100   } else if( op == Op_SubI || op == Op_SubL ) {
1101     // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1102     return n->Opcode() == op && n->in(2) == this;
1103   }
1104   return false;
1105 };
1106 
1107 //--------------------------find_exact_control---------------------------------
1108 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1109 Node* Node::find_exact_control(Node* ctrl) {
1110   if (ctrl == NULL && this->is_Region())
1111     ctrl = this->as_Region()->is_copy();
1112 
1113   if (ctrl != NULL && ctrl->is_CatchProj()) {
1114     if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1115       ctrl = ctrl->in(0);
1116     if (ctrl != NULL && !ctrl->is_top())
1117       ctrl = ctrl->in(0);
1118   }
1119 
1120   if (ctrl != NULL && ctrl->is_Proj())
1121     ctrl = ctrl->in(0);
1122 
1123   return ctrl;
1124 }
1125 
1126 //--------------------------dominates------------------------------------------
1127 // Helper function for MemNode::all_controls_dominate().
1128 // Check if 'this' control node dominates or equal to 'sub' control node.
1129 // We already know that if any path back to Root or Start reaches 'this',
1130 // then all paths so, so this is a simple search for one example,
1131 // not an exhaustive search for a counterexample.
1132 bool Node::dominates(Node* sub, Node_List &nlist) {
1133   assert(this->is_CFG(), "expecting control");
1134   assert(sub != NULL && sub->is_CFG(), "expecting control");
1135 
1136   // detect dead cycle without regions
1137   int iterations_without_region_limit = DominatorSearchLimit;
1138 
1139   Node* orig_sub = sub;
1140   Node* dom      = this;
1141   bool  met_dom  = false;
1142   nlist.clear();
1143 
1144   // Walk 'sub' backward up the chain to 'dom', watching for regions.
1145   // After seeing 'dom', continue up to Root or Start.
1146   // If we hit a region (backward split point), it may be a loop head.
1147   // Keep going through one of the region's inputs.  If we reach the
1148   // same region again, go through a different input.  Eventually we
1149   // will either exit through the loop head, or give up.
1150   // (If we get confused, break out and return a conservative 'false'.)
1151   while (sub != NULL) {
1152     if (sub->is_top())  break; // Conservative answer for dead code.
1153     if (sub == dom) {
1154       if (nlist.size() == 0) {
1155         // No Region nodes except loops were visited before and the EntryControl
1156         // path was taken for loops: it did not walk in a cycle.
1157         return true;
1158       } else if (met_dom) {
1159         break;          // already met before: walk in a cycle
1160       } else {
1161         // Region nodes were visited. Continue walk up to Start or Root
1162         // to make sure that it did not walk in a cycle.
1163         met_dom = true; // first time meet
1164         iterations_without_region_limit = DominatorSearchLimit; // Reset
1165      }
1166     }
1167     if (sub->is_Start() || sub->is_Root()) {
1168       // Success if we met 'dom' along a path to Start or Root.
1169       // We assume there are no alternative paths that avoid 'dom'.
1170       // (This assumption is up to the caller to ensure!)
1171       return met_dom;
1172     }
1173     Node* up = sub->in(0);
1174     // Normalize simple pass-through regions and projections:
1175     up = sub->find_exact_control(up);
1176     // If sub == up, we found a self-loop.  Try to push past it.
1177     if (sub == up && sub->is_Loop()) {
1178       // Take loop entry path on the way up to 'dom'.
1179       up = sub->in(1); // in(LoopNode::EntryControl);
1180     } else if (sub == up && sub->is_Region() && sub->req() != 3) {
1181       // Always take in(1) path on the way up to 'dom' for clone regions
1182       // (with only one input) or regions which merge > 2 paths
1183       // (usually used to merge fast/slow paths).
1184       up = sub->in(1);
1185     } else if (sub == up && sub->is_Region()) {
1186       // Try both paths for Regions with 2 input paths (it may be a loop head).
1187       // It could give conservative 'false' answer without information
1188       // which region's input is the entry path.
1189       iterations_without_region_limit = DominatorSearchLimit; // Reset
1190 
1191       bool region_was_visited_before = false;
1192       // Was this Region node visited before?
1193       // If so, we have reached it because we accidentally took a
1194       // loop-back edge from 'sub' back into the body of the loop,
1195       // and worked our way up again to the loop header 'sub'.
1196       // So, take the first unexplored path on the way up to 'dom'.
1197       for (int j = nlist.size() - 1; j >= 0; j--) {
1198         intptr_t ni = (intptr_t)nlist.at(j);
1199         Node* visited = (Node*)(ni & ~1);
1200         bool  visited_twice_already = ((ni & 1) != 0);
1201         if (visited == sub) {
1202           if (visited_twice_already) {
1203             // Visited 2 paths, but still stuck in loop body.  Give up.
1204             return false;
1205           }
1206           // The Region node was visited before only once.
1207           // (We will repush with the low bit set, below.)
1208           nlist.remove(j);
1209           // We will find a new edge and re-insert.
1210           region_was_visited_before = true;
1211           break;
1212         }
1213       }
1214 
1215       // Find an incoming edge which has not been seen yet; walk through it.
1216       assert(up == sub, "");
1217       uint skip = region_was_visited_before ? 1 : 0;
1218       for (uint i = 1; i < sub->req(); i++) {
1219         Node* in = sub->in(i);
1220         if (in != NULL && !in->is_top() && in != sub) {
1221           if (skip == 0) {
1222             up = in;
1223             break;
1224           }
1225           --skip;               // skip this nontrivial input
1226         }
1227       }
1228 
1229       // Set 0 bit to indicate that both paths were taken.
1230       nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1231     }
1232 
1233     if (up == sub) {
1234       break;    // some kind of tight cycle
1235     }
1236     if (up == orig_sub && met_dom) {
1237       // returned back after visiting 'dom'
1238       break;    // some kind of cycle
1239     }
1240     if (--iterations_without_region_limit < 0) {
1241       break;    // dead cycle
1242     }
1243     sub = up;
1244   }
1245 
1246   // Did not meet Root or Start node in pred. chain.
1247   // Conservative answer for dead code.
1248   return false;
1249 }
1250 
1251 //------------------------------remove_dead_region-----------------------------
1252 // This control node is dead.  Follow the subgraph below it making everything
1253 // using it dead as well.  This will happen normally via the usual IterGVN
1254 // worklist but this call is more efficient.  Do not update use-def info
1255 // inside the dead region, just at the borders.
1256 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1257   // Con's are a popular node to re-hit in the hash table again.
1258   if( dead->is_Con() ) return;
1259 
1260   // Can't put ResourceMark here since igvn->_worklist uses the same arena
1261   // for verify pass with +VerifyOpto and we add/remove elements in it here.
1262   Node_List  nstack(Thread::current()->resource_area());
1263 
1264   Node *top = igvn->C->top();
1265   nstack.push(dead);
1266 
1267   while (nstack.size() > 0) {
1268     dead = nstack.pop();
1269     if (dead->outcnt() > 0) {
1270       // Keep dead node on stack until all uses are processed.
1271       nstack.push(dead);
1272       // For all Users of the Dead...    ;-)
1273       for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1274         Node* use = dead->last_out(k);
1275         igvn->hash_delete(use);       // Yank from hash table prior to mod
1276         if (use->in(0) == dead) {     // Found another dead node
1277           assert (!use->is_Con(), "Control for Con node should be Root node.");
1278           use->set_req(0, top);       // Cut dead edge to prevent processing
1279           nstack.push(use);           // the dead node again.
1280         } else {                      // Else found a not-dead user
1281           for (uint j = 1; j < use->req(); j++) {
1282             if (use->in(j) == dead) { // Turn all dead inputs into TOP
1283               use->set_req(j, top);
1284             }
1285           }
1286           igvn->_worklist.push(use);
1287         }
1288         // Refresh the iterator, since any number of kills might have happened.
1289         k = dead->last_outs(kmin);
1290       }
1291     } else { // (dead->outcnt() == 0)
1292       // Done with outputs.
1293       igvn->hash_delete(dead);
1294       igvn->_worklist.remove(dead);
1295       igvn->set_type(dead, Type::TOP);
1296       if (dead->is_macro()) {
1297         igvn->C->remove_macro_node(dead);
1298       }
1299       if (dead->is_expensive()) {
1300         igvn->C->remove_expensive_node(dead);
1301       }
1302       igvn->C->record_dead_node(dead->_idx);
1303       // Kill all inputs to the dead guy
1304       for (uint i=0; i < dead->req(); i++) {
1305         Node *n = dead->in(i);      // Get input to dead guy
1306         if (n != NULL && !n->is_top()) { // Input is valid?
1307           dead->set_req(i, top);    // Smash input away
1308           if (n->outcnt() == 0) {   // Input also goes dead?
1309             if (!n->is_Con())
1310               nstack.push(n);       // Clear it out as well
1311           } else if (n->outcnt() == 1 &&
1312                      n->has_special_unique_user()) {
1313             igvn->add_users_to_worklist( n );
1314           } else if (n->outcnt() <= 2 && n->is_Store()) {
1315             // Push store's uses on worklist to enable folding optimization for
1316             // store/store and store/load to the same address.
1317             // The restriction (outcnt() <= 2) is the same as in set_req_X()
1318             // and remove_globally_dead_node().
1319             igvn->add_users_to_worklist( n );
1320           }
1321         }
1322       }
1323     } // (dead->outcnt() == 0)
1324   }   // while (nstack.size() > 0) for outputs
1325   return;
1326 }
1327 
1328 //------------------------------remove_dead_region-----------------------------
1329 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1330   Node *n = in(0);
1331   if( !n ) return false;
1332   // Lost control into this guy?  I.e., it became unreachable?
1333   // Aggressively kill all unreachable code.
1334   if (can_reshape && n->is_top()) {
1335     kill_dead_code(this, phase->is_IterGVN());
1336     return false; // Node is dead.
1337   }
1338 
1339   if( n->is_Region() && n->as_Region()->is_copy() ) {
1340     Node *m = n->nonnull_req();
1341     set_req(0, m);
1342     return true;
1343   }
1344   return false;
1345 }
1346 
1347 //------------------------------Ideal_DU_postCCP-------------------------------
1348 // Idealize graph, using DU info.  Must clone result into new-space
1349 Node *Node::Ideal_DU_postCCP( PhaseCCP * ) {
1350   return NULL;                 // Default to no change
1351 }
1352 
1353 //------------------------------hash-------------------------------------------
1354 // Hash function over Nodes.
1355 uint Node::hash() const {
1356   uint sum = 0;
1357   for( uint i=0; i<_cnt; i++ )  // Add in all inputs
1358     sum = (sum<<1)-(uintptr_t)in(i);        // Ignore embedded NULLs
1359   return (sum>>2) + _cnt + Opcode();
1360 }
1361 
1362 //------------------------------cmp--------------------------------------------
1363 // Compare special parts of simple Nodes
1364 uint Node::cmp( const Node &n ) const {
1365   return 1;                     // Must be same
1366 }
1367 
1368 //------------------------------rematerialize-----------------------------------
1369 // Should we clone rather than spill this instruction?
1370 bool Node::rematerialize() const {
1371   if ( is_Mach() )
1372     return this->as_Mach()->rematerialize();
1373   else
1374     return (_flags & Flag_rematerialize) != 0;
1375 }
1376 
1377 //------------------------------needs_anti_dependence_check---------------------
1378 // Nodes which use memory without consuming it, hence need antidependences.
1379 bool Node::needs_anti_dependence_check() const {
1380   if( req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0 )
1381     return false;
1382   else
1383     return in(1)->bottom_type()->has_memory();
1384 }
1385 
1386 
1387 // Get an integer constant from a ConNode (or CastIINode).
1388 // Return a default value if there is no apparent constant here.
1389 const TypeInt* Node::find_int_type() const {
1390   if (this->is_Type()) {
1391     return this->as_Type()->type()->isa_int();
1392   } else if (this->is_Con()) {
1393     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1394     return this->bottom_type()->isa_int();
1395   }
1396   return NULL;
1397 }
1398 
1399 // Get a pointer constant from a ConstNode.
1400 // Returns the constant if it is a pointer ConstNode
1401 intptr_t Node::get_ptr() const {
1402   assert( Opcode() == Op_ConP, "" );
1403   return ((ConPNode*)this)->type()->is_ptr()->get_con();
1404 }
1405 
1406 // Get a narrow oop constant from a ConNNode.
1407 intptr_t Node::get_narrowcon() const {
1408   assert( Opcode() == Op_ConN, "" );
1409   return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1410 }
1411 
1412 // Get a long constant from a ConNode.
1413 // Return a default value if there is no apparent constant here.
1414 const TypeLong* Node::find_long_type() const {
1415   if (this->is_Type()) {
1416     return this->as_Type()->type()->isa_long();
1417   } else if (this->is_Con()) {
1418     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1419     return this->bottom_type()->isa_long();
1420   }
1421   return NULL;
1422 }
1423 
1424 
1425 /**
1426  * Return a ptr type for nodes which should have it.
1427  */
1428 const TypePtr* Node::get_ptr_type() const {
1429   const TypePtr* tp = this->bottom_type()->make_ptr();
1430 #ifdef ASSERT
1431   if (tp == NULL) {
1432     this->dump(1);
1433     assert((tp != NULL), "unexpected node type");
1434   }
1435 #endif
1436   return tp;
1437 }
1438 
1439 // Get a double constant from a ConstNode.
1440 // Returns the constant if it is a double ConstNode
1441 jdouble Node::getd() const {
1442   assert( Opcode() == Op_ConD, "" );
1443   return ((ConDNode*)this)->type()->is_double_constant()->getd();
1444 }
1445 
1446 // Get a float constant from a ConstNode.
1447 // Returns the constant if it is a float ConstNode
1448 jfloat Node::getf() const {
1449   assert( Opcode() == Op_ConF, "" );
1450   return ((ConFNode*)this)->type()->is_float_constant()->getf();
1451 }
1452 
1453 #ifndef PRODUCT
1454 
1455 //----------------------------NotANode----------------------------------------
1456 // Used in debugging code to avoid walking across dead or uninitialized edges.
1457 static inline bool NotANode(const Node* n) {
1458   if (n == NULL)                   return true;
1459   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1460   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1461   return false;
1462 }
1463 
1464 
1465 //------------------------------find------------------------------------------
1466 // Find a neighbor of this Node with the given _idx
1467 // If idx is negative, find its absolute value, following both _in and _out.
1468 static void find_recur(Compile* C,  Node* &result, Node *n, int idx, bool only_ctrl,
1469                         VectorSet* old_space, VectorSet* new_space ) {
1470   int node_idx = (idx >= 0) ? idx : -idx;
1471   if (NotANode(n))  return;  // Gracefully handle NULL, -1, 0xabababab, etc.
1472   // Contained in new_space or old_space?   Check old_arena first since it's mostly empty.
1473   VectorSet *v = C->old_arena()->contains(n) ? old_space : new_space;
1474   if( v->test(n->_idx) ) return;
1475   if( (int)n->_idx == node_idx
1476       debug_only(|| n->debug_idx() == node_idx) ) {
1477     if (result != NULL)
1478       tty->print("find: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1479                  (uintptr_t)result, (uintptr_t)n, node_idx);
1480     result = n;
1481   }
1482   v->set(n->_idx);
1483   for( uint i=0; i<n->len(); i++ ) {
1484     if( only_ctrl && !(n->is_Region()) && (n->Opcode() != Op_Root) && (i != TypeFunc::Control) ) continue;
1485     find_recur(C, result, n->in(i), idx, only_ctrl, old_space, new_space );
1486   }
1487   // Search along forward edges also:
1488   if (idx < 0 && !only_ctrl) {
1489     for( uint j=0; j<n->outcnt(); j++ ) {
1490       find_recur(C, result, n->raw_out(j), idx, only_ctrl, old_space, new_space );
1491     }
1492   }
1493 #ifdef ASSERT
1494   // Search along debug_orig edges last, checking for cycles
1495   Node* orig = n->debug_orig();
1496   if (orig != NULL) {
1497     do {
1498       if (NotANode(orig))  break;
1499       find_recur(C, result, orig, idx, only_ctrl, old_space, new_space );
1500       orig = orig->debug_orig();
1501     } while (orig != NULL && orig != n->debug_orig());
1502   }
1503 #endif //ASSERT
1504 }
1505 
1506 // call this from debugger:
1507 Node* find_node(Node* n, int idx) {
1508   return n->find(idx);
1509 }
1510 
1511 //------------------------------find-------------------------------------------
1512 Node* Node::find(int idx) const {
1513   ResourceArea *area = Thread::current()->resource_area();
1514   VectorSet old_space(area), new_space(area);
1515   Node* result = NULL;
1516   find_recur(Compile::current(), result, (Node*) this, idx, false, &old_space, &new_space );
1517   return result;
1518 }
1519 
1520 //------------------------------find_ctrl--------------------------------------
1521 // Find an ancestor to this node in the control history with given _idx
1522 Node* Node::find_ctrl(int idx) const {
1523   ResourceArea *area = Thread::current()->resource_area();
1524   VectorSet old_space(area), new_space(area);
1525   Node* result = NULL;
1526   find_recur(Compile::current(), result, (Node*) this, idx, true, &old_space, &new_space );
1527   return result;
1528 }
1529 #endif
1530 
1531 
1532 
1533 #ifndef PRODUCT
1534 int Node::_in_dump_cnt = 0;
1535 
1536 // -----------------------------Name-------------------------------------------
1537 extern const char *NodeClassNames[];
1538 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
1539 
1540 static bool is_disconnected(const Node* n) {
1541   for (uint i = 0; i < n->req(); i++) {
1542     if (n->in(i) != NULL)  return false;
1543   }
1544   return true;
1545 }
1546 
1547 #ifdef ASSERT
1548 static void dump_orig(Node* orig, outputStream *st) {
1549   Compile* C = Compile::current();
1550   if (NotANode(orig)) orig = NULL;
1551   if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1552   if (orig == NULL) return;
1553   st->print(" !orig=");
1554   Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
1555   if (NotANode(fast)) fast = NULL;
1556   while (orig != NULL) {
1557     bool discon = is_disconnected(orig);  // if discon, print [123] else 123
1558     if (discon) st->print("[");
1559     if (!Compile::current()->node_arena()->contains(orig))
1560       st->print("o");
1561     st->print("%d", orig->_idx);
1562     if (discon) st->print("]");
1563     orig = orig->debug_orig();
1564     if (NotANode(orig)) orig = NULL;
1565     if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1566     if (orig != NULL) st->print(",");
1567     if (fast != NULL) {
1568       // Step fast twice for each single step of orig:
1569       fast = fast->debug_orig();
1570       if (NotANode(fast)) fast = NULL;
1571       if (fast != NULL && fast != orig) {
1572         fast = fast->debug_orig();
1573         if (NotANode(fast)) fast = NULL;
1574       }
1575       if (fast == orig) {
1576         st->print("...");
1577         break;
1578       }
1579     }
1580   }
1581 }
1582 
1583 void Node::set_debug_orig(Node* orig) {
1584   _debug_orig = orig;
1585   if (BreakAtNode == 0)  return;
1586   if (NotANode(orig))  orig = NULL;
1587   int trip = 10;
1588   while (orig != NULL) {
1589     if (orig->debug_idx() == BreakAtNode || (int)orig->_idx == BreakAtNode) {
1590       tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d orig._idx=%d orig._debug_idx=%d",
1591                     this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
1592       BREAKPOINT;
1593     }
1594     orig = orig->debug_orig();
1595     if (NotANode(orig))  orig = NULL;
1596     if (trip-- <= 0)  break;
1597   }
1598 }
1599 #endif //ASSERT
1600 
1601 //------------------------------dump------------------------------------------
1602 // Dump a Node
1603 void Node::dump(const char* suffix, outputStream *st) const {
1604   Compile* C = Compile::current();
1605   bool is_new = C->node_arena()->contains(this);
1606   _in_dump_cnt++;
1607   st->print("%c%d\t%s\t=== ", is_new ? ' ' : 'o', _idx, Name());
1608 
1609   // Dump the required and precedence inputs
1610   dump_req(st);
1611   dump_prec(st);
1612   // Dump the outputs
1613   dump_out(st);
1614 
1615   if (is_disconnected(this)) {
1616 #ifdef ASSERT
1617     st->print("  [%d]",debug_idx());
1618     dump_orig(debug_orig(), st);
1619 #endif
1620     st->cr();
1621     _in_dump_cnt--;
1622     return;                     // don't process dead nodes
1623   }
1624 
1625   // Dump node-specific info
1626   dump_spec(st);
1627 #ifdef ASSERT
1628   // Dump the non-reset _debug_idx
1629   if (Verbose && WizardMode) {
1630     st->print("  [%d]",debug_idx());
1631   }
1632 #endif
1633 
1634   const Type *t = bottom_type();
1635 
1636   if (t != NULL && (t->isa_instptr() || t->isa_klassptr())) {
1637     const TypeInstPtr  *toop = t->isa_instptr();
1638     const TypeKlassPtr *tkls = t->isa_klassptr();
1639     ciKlass*           klass = toop ? toop->klass() : (tkls ? tkls->klass() : NULL );
1640     if (klass && klass->is_loaded() && klass->is_interface()) {
1641       st->print("  Interface:");
1642     } else if (toop) {
1643       st->print("  Oop:");
1644     } else if (tkls) {
1645       st->print("  Klass:");
1646     }
1647     t->dump_on(st);
1648   } else if (t == Type::MEMORY) {
1649     st->print("  Memory:");
1650     MemNode::dump_adr_type(this, adr_type(), st);
1651   } else if (Verbose || WizardMode) {
1652     st->print("  Type:");
1653     if (t) {
1654       t->dump_on(st);
1655     } else {
1656       st->print("no type");
1657     }
1658   } else if (t->isa_vect() && this->is_MachSpillCopy()) {
1659     // Dump MachSpillcopy vector type.
1660     t->dump_on(st);
1661   }
1662   if (is_new) {
1663     debug_only(dump_orig(debug_orig(), st));
1664     Node_Notes* nn = C->node_notes_at(_idx);
1665     if (nn != NULL && !nn->is_clear()) {
1666       if (nn->jvms() != NULL) {
1667         st->print(" !jvms:");
1668         nn->jvms()->dump_spec(st);
1669       }
1670     }
1671   }
1672   if (suffix) st->print(suffix);
1673   _in_dump_cnt--;
1674 }
1675 
1676 //------------------------------dump_req--------------------------------------
1677 void Node::dump_req(outputStream *st) const {
1678   // Dump the required input edges
1679   for (uint i = 0; i < req(); i++) {    // For all required inputs
1680     Node* d = in(i);
1681     if (d == NULL) {
1682       st->print("_ ");
1683     } else if (NotANode(d)) {
1684       st->print("NotANode ");  // uninitialized, sentinel, garbage, etc.
1685     } else {
1686       st->print("%c%d ", Compile::current()->node_arena()->contains(d) ? ' ' : 'o', d->_idx);
1687     }
1688   }
1689 }
1690 
1691 
1692 //------------------------------dump_prec-------------------------------------
1693 void Node::dump_prec(outputStream *st) const {
1694   // Dump the precedence edges
1695   int any_prec = 0;
1696   for (uint i = req(); i < len(); i++) {       // For all precedence inputs
1697     Node* p = in(i);
1698     if (p != NULL) {
1699       if (!any_prec++) st->print(" |");
1700       if (NotANode(p)) { st->print("NotANode "); continue; }
1701       st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
1702     }
1703   }
1704 }
1705 
1706 //------------------------------dump_out--------------------------------------
1707 void Node::dump_out(outputStream *st) const {
1708   // Delimit the output edges
1709   st->print(" [[");
1710   // Dump the output edges
1711   for (uint i = 0; i < _outcnt; i++) {    // For all outputs
1712     Node* u = _out[i];
1713     if (u == NULL) {
1714       st->print("_ ");
1715     } else if (NotANode(u)) {
1716       st->print("NotANode ");
1717     } else {
1718       st->print("%c%d ", Compile::current()->node_arena()->contains(u) ? ' ' : 'o', u->_idx);
1719     }
1720   }
1721   st->print("]] ");
1722 }
1723 
1724 //------------------------------dump_nodes-------------------------------------
1725 static void dump_nodes(const Node* start, int d, bool only_ctrl) {
1726   Node* s = (Node*)start; // remove const
1727   if (NotANode(s)) return;
1728 
1729   uint depth = (uint)ABS(d);
1730   int direction = d;
1731   Compile* C = Compile::current();
1732   GrowableArray <Node *> nstack(C->unique());
1733 
1734   nstack.append(s);
1735   int begin = 0;
1736   int end = 0;
1737   for(uint i = 0; i < depth; i++) {
1738     end = nstack.length();
1739     for(int j = begin; j < end; j++) {
1740       Node* tp  = nstack.at(j);
1741       uint limit = direction > 0 ? tp->len() : tp->outcnt();
1742       for(uint k = 0; k < limit; k++) {
1743         Node* n = direction > 0 ? tp->in(k) : tp->raw_out(k);
1744 
1745         if (NotANode(n))  continue;
1746         // do not recurse through top or the root (would reach unrelated stuff)
1747         if (n->is_Root() || n->is_top())  continue;
1748         if (only_ctrl && !n->is_CFG()) continue;
1749 
1750         bool on_stack = nstack.contains(n);
1751         if (!on_stack) {
1752           nstack.append(n);
1753         }
1754       }
1755     }
1756     begin = end;
1757   }
1758   end = nstack.length();
1759   if (direction > 0) {
1760     for(int j = end-1; j >= 0; j--) {
1761       nstack.at(j)->dump();
1762     }
1763   } else {
1764     for(int j = 0; j < end; j++) {
1765       nstack.at(j)->dump();
1766     }
1767   }
1768 }
1769 
1770 //------------------------------dump-------------------------------------------
1771 void Node::dump(int d) const {
1772   dump_nodes(this, d, false);
1773 }
1774 
1775 //------------------------------dump_ctrl--------------------------------------
1776 // Dump a Node's control history to depth
1777 void Node::dump_ctrl(int d) const {
1778   dump_nodes(this, d, true);
1779 }
1780 
1781 // VERIFICATION CODE
1782 // For each input edge to a node (ie - for each Use-Def edge), verify that
1783 // there is a corresponding Def-Use edge.
1784 //------------------------------verify_edges-----------------------------------
1785 void Node::verify_edges(Unique_Node_List &visited) {
1786   uint i, j, idx;
1787   int  cnt;
1788   Node *n;
1789 
1790   // Recursive termination test
1791   if (visited.member(this))  return;
1792   visited.push(this);
1793 
1794   // Walk over all input edges, checking for correspondence
1795   for( i = 0; i < len(); i++ ) {
1796     n = in(i);
1797     if (n != NULL && !n->is_top()) {
1798       // Count instances of (Node *)this
1799       cnt = 0;
1800       for (idx = 0; idx < n->_outcnt; idx++ ) {
1801         if (n->_out[idx] == (Node *)this)  cnt++;
1802       }
1803       assert( cnt > 0,"Failed to find Def-Use edge." );
1804       // Check for duplicate edges
1805       // walk the input array downcounting the input edges to n
1806       for( j = 0; j < len(); j++ ) {
1807         if( in(j) == n ) cnt--;
1808       }
1809       assert( cnt == 0,"Mismatched edge count.");
1810     } else if (n == NULL) {
1811       assert(i >= req() || i == 0 || is_Region() || is_Phi(), "only regions or phis have null data edges");
1812     } else {
1813       assert(n->is_top(), "sanity");
1814       // Nothing to check.
1815     }
1816   }
1817   // Recursive walk over all input edges
1818   for( i = 0; i < len(); i++ ) {
1819     n = in(i);
1820     if( n != NULL )
1821       in(i)->verify_edges(visited);
1822   }
1823 }
1824 
1825 //------------------------------verify_recur-----------------------------------
1826 static const Node *unique_top = NULL;
1827 
1828 void Node::verify_recur(const Node *n, int verify_depth,
1829                         VectorSet &old_space, VectorSet &new_space) {
1830   if ( verify_depth == 0 )  return;
1831   if (verify_depth > 0)  --verify_depth;
1832 
1833   Compile* C = Compile::current();
1834 
1835   // Contained in new_space or old_space?
1836   VectorSet *v = C->node_arena()->contains(n) ? &new_space : &old_space;
1837   // Check for visited in the proper space.  Numberings are not unique
1838   // across spaces so we need a separate VectorSet for each space.
1839   if( v->test_set(n->_idx) ) return;
1840 
1841   if (n->is_Con() && n->bottom_type() == Type::TOP) {
1842     if (C->cached_top_node() == NULL)
1843       C->set_cached_top_node((Node*)n);
1844     assert(C->cached_top_node() == n, "TOP node must be unique");
1845   }
1846 
1847   for( uint i = 0; i < n->len(); i++ ) {
1848     Node *x = n->in(i);
1849     if (!x || x->is_top()) continue;
1850 
1851     // Verify my input has a def-use edge to me
1852     if (true /*VerifyDefUse*/) {
1853       // Count use-def edges from n to x
1854       int cnt = 0;
1855       for( uint j = 0; j < n->len(); j++ )
1856         if( n->in(j) == x )
1857           cnt++;
1858       // Count def-use edges from x to n
1859       uint max = x->_outcnt;
1860       for( uint k = 0; k < max; k++ )
1861         if (x->_out[k] == n)
1862           cnt--;
1863       assert( cnt == 0, "mismatched def-use edge counts" );
1864     }
1865 
1866     verify_recur(x, verify_depth, old_space, new_space);
1867   }
1868 
1869 }
1870 
1871 //------------------------------verify-----------------------------------------
1872 // Check Def-Use info for my subgraph
1873 void Node::verify() const {
1874   Compile* C = Compile::current();
1875   Node* old_top = C->cached_top_node();
1876   ResourceMark rm;
1877   ResourceArea *area = Thread::current()->resource_area();
1878   VectorSet old_space(area), new_space(area);
1879   verify_recur(this, -1, old_space, new_space);
1880   C->set_cached_top_node(old_top);
1881 }
1882 #endif
1883 
1884 
1885 //------------------------------walk-------------------------------------------
1886 // Graph walk, with both pre-order and post-order functions
1887 void Node::walk(NFunc pre, NFunc post, void *env) {
1888   VectorSet visited(Thread::current()->resource_area()); // Setup for local walk
1889   walk_(pre, post, env, visited);
1890 }
1891 
1892 void Node::walk_(NFunc pre, NFunc post, void *env, VectorSet &visited) {
1893   if( visited.test_set(_idx) ) return;
1894   pre(*this,env);               // Call the pre-order walk function
1895   for( uint i=0; i<_max; i++ )
1896     if( in(i) )                 // Input exists and is not walked?
1897       in(i)->walk_(pre,post,env,visited); // Walk it with pre & post functions
1898   post(*this,env);              // Call the post-order walk function
1899 }
1900 
1901 void Node::nop(Node &, void*) {}
1902 
1903 //------------------------------Registers--------------------------------------
1904 // Do we Match on this edge index or not?  Generally false for Control
1905 // and true for everything else.  Weird for calls & returns.
1906 uint Node::match_edge(uint idx) const {
1907   return idx;                   // True for other than index 0 (control)
1908 }
1909 
1910 static RegMask _not_used_at_all;
1911 // Register classes are defined for specific machines
1912 const RegMask &Node::out_RegMask() const {
1913   ShouldNotCallThis();
1914   return _not_used_at_all;
1915 }
1916 
1917 const RegMask &Node::in_RegMask(uint) const {
1918   ShouldNotCallThis();
1919   return _not_used_at_all;
1920 }
1921 
1922 //=============================================================================
1923 //-----------------------------------------------------------------------------
1924 void Node_Array::reset( Arena *new_arena ) {
1925   _a->Afree(_nodes,_max*sizeof(Node*));
1926   _max   = 0;
1927   _nodes = NULL;
1928   _a     = new_arena;
1929 }
1930 
1931 //------------------------------clear------------------------------------------
1932 // Clear all entries in _nodes to NULL but keep storage
1933 void Node_Array::clear() {
1934   Copy::zero_to_bytes( _nodes, _max*sizeof(Node*) );
1935 }
1936 
1937 //-----------------------------------------------------------------------------
1938 void Node_Array::grow( uint i ) {
1939   if( !_max ) {
1940     _max = 1;
1941     _nodes = (Node**)_a->Amalloc( _max * sizeof(Node*) );
1942     _nodes[0] = NULL;
1943   }
1944   uint old = _max;
1945   while( i >= _max ) _max <<= 1;        // Double to fit
1946   _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
1947   Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
1948 }
1949 
1950 //-----------------------------------------------------------------------------
1951 void Node_Array::insert( uint i, Node *n ) {
1952   if( _nodes[_max-1] ) grow(_max);      // Get more space if full
1953   Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i+1], ((_max-i-1)*sizeof(Node*)));
1954   _nodes[i] = n;
1955 }
1956 
1957 //-----------------------------------------------------------------------------
1958 void Node_Array::remove( uint i ) {
1959   Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i+1], (HeapWord*)&_nodes[i], ((_max-i-1)*sizeof(Node*)));
1960   _nodes[_max-1] = NULL;
1961 }
1962 
1963 //-----------------------------------------------------------------------------
1964 void Node_Array::sort( C_sort_func_t func) {
1965   qsort( _nodes, _max, sizeof( Node* ), func );
1966 }
1967 
1968 //-----------------------------------------------------------------------------
1969 void Node_Array::dump() const {
1970 #ifndef PRODUCT
1971   for( uint i = 0; i < _max; i++ ) {
1972     Node *nn = _nodes[i];
1973     if( nn != NULL ) {
1974       tty->print("%5d--> ",i); nn->dump();
1975     }
1976   }
1977 #endif
1978 }
1979 
1980 //--------------------------is_iteratively_computed------------------------------
1981 // Operation appears to be iteratively computed (such as an induction variable)
1982 // It is possible for this operation to return false for a loop-varying
1983 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1984 bool Node::is_iteratively_computed() {
1985   if (ideal_reg()) { // does operation have a result register?
1986     for (uint i = 1; i < req(); i++) {
1987       Node* n = in(i);
1988       if (n != NULL && n->is_Phi()) {
1989         for (uint j = 1; j < n->req(); j++) {
1990           if (n->in(j) == this) {
1991             return true;
1992           }
1993         }
1994       }
1995     }
1996   }
1997   return false;
1998 }
1999 
2000 //--------------------------find_similar------------------------------
2001 // Return a node with opcode "opc" and same inputs as "this" if one can
2002 // be found; Otherwise return NULL;
2003 Node* Node::find_similar(int opc) {
2004   if (req() >= 2) {
2005     Node* def = in(1);
2006     if (def && def->outcnt() >= 2) {
2007       for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
2008         Node* use = def->fast_out(i);
2009         if (use->Opcode() == opc &&
2010             use->req() == req()) {
2011           uint j;
2012           for (j = 0; j < use->req(); j++) {
2013             if (use->in(j) != in(j)) {
2014               break;
2015             }
2016           }
2017           if (j == use->req()) {
2018             return use;
2019           }
2020         }
2021       }
2022     }
2023   }
2024   return NULL;
2025 }
2026 
2027 
2028 //--------------------------unique_ctrl_out------------------------------
2029 // Return the unique control out if only one. Null if none or more than one.
2030 Node* Node::unique_ctrl_out() {
2031   Node* found = NULL;
2032   for (uint i = 0; i < outcnt(); i++) {
2033     Node* use = raw_out(i);
2034     if (use->is_CFG() && use != this) {
2035       if (found != NULL) return NULL;
2036       found = use;
2037     }
2038   }
2039   return found;
2040 }
2041 
2042 //=============================================================================
2043 //------------------------------yank-------------------------------------------
2044 // Find and remove
2045 void Node_List::yank( Node *n ) {
2046   uint i;
2047   for( i = 0; i < _cnt; i++ )
2048     if( _nodes[i] == n )
2049       break;
2050 
2051   if( i < _cnt )
2052     _nodes[i] = _nodes[--_cnt];
2053 }
2054 
2055 //------------------------------dump-------------------------------------------
2056 void Node_List::dump() const {
2057 #ifndef PRODUCT
2058   for( uint i = 0; i < _cnt; i++ )
2059     if( _nodes[i] ) {
2060       tty->print("%5d--> ",i);
2061       _nodes[i]->dump();
2062     }
2063 #endif
2064 }
2065 
2066 //=============================================================================
2067 //------------------------------remove-----------------------------------------
2068 void Unique_Node_List::remove( Node *n ) {
2069   if( _in_worklist[n->_idx] ) {
2070     for( uint i = 0; i < size(); i++ )
2071       if( _nodes[i] == n ) {
2072         map(i,Node_List::pop());
2073         _in_worklist >>= n->_idx;
2074         return;
2075       }
2076     ShouldNotReachHere();
2077   }
2078 }
2079 
2080 //-----------------------remove_useless_nodes----------------------------------
2081 // Remove useless nodes from worklist
2082 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
2083 
2084   for( uint i = 0; i < size(); ++i ) {
2085     Node *n = at(i);
2086     assert( n != NULL, "Did not expect null entries in worklist");
2087     if( ! useful.test(n->_idx) ) {
2088       _in_worklist >>= n->_idx;
2089       map(i,Node_List::pop());
2090       // Node *replacement = Node_List::pop();
2091       // if( i != size() ) { // Check if removing last entry
2092       //   _nodes[i] = replacement;
2093       // }
2094       --i;  // Visit popped node
2095       // If it was last entry, loop terminates since size() was also reduced
2096     }
2097   }
2098 }
2099 
2100 //=============================================================================
2101 void Node_Stack::grow() {
2102   size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
2103   size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
2104   size_t max = old_max << 1;             // max * 2
2105   _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
2106   _inode_max = _inodes + max;
2107   _inode_top = _inodes + old_top;        // restore _top
2108 }
2109 
2110 // Node_Stack is used to map nodes.
2111 Node* Node_Stack::find(uint idx) const {
2112   uint sz = size();
2113   for (uint i=0; i < sz; i++) {
2114     if (idx == index_at(i) )
2115       return node_at(i);
2116   }
2117   return NULL;
2118 }
2119 
2120 //=============================================================================
2121 uint TypeNode::size_of() const { return sizeof(*this); }
2122 #ifndef PRODUCT
2123 void TypeNode::dump_spec(outputStream *st) const {
2124   if( !Verbose && !WizardMode ) {
2125     // standard dump does this in Verbose and WizardMode
2126     st->print(" #"); _type->dump_on(st);
2127   }
2128 }
2129 #endif
2130 uint TypeNode::hash() const {
2131   return Node::hash() + _type->hash();
2132 }
2133 uint TypeNode::cmp( const Node &n ) const
2134 { return !Type::cmp( _type, ((TypeNode&)n)._type ); }
2135 const Type *TypeNode::bottom_type() const { return _type; }
2136 const Type *TypeNode::Value( PhaseTransform * ) const { return _type; }
2137 
2138 //------------------------------ideal_reg--------------------------------------
2139 uint TypeNode::ideal_reg() const {
2140   return _type->ideal_reg();
2141 }