1 /*
   2  * Copyright (c) 1997, 2021, 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 #ifndef SHARE_OPTO_NODE_HPP
  26 #define SHARE_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 #include "utilities/copy.hpp"
  32 
  33 // Portions of code courtesy of Clifford Click
  34 
  35 // Optimization - Graph Style
  36 
  37 
  38 class AbstractLockNode;
  39 class AddNode;
  40 class AddPNode;
  41 class AliasInfo;
  42 class AllocateArrayNode;
  43 class AllocateNode;
  44 class ArrayCopyNode;
  45 class BaseCountedLoopNode;
  46 class BaseCountedLoopEndNode;
  47 class BlackholeNode;
  48 class Block;
  49 class BoolNode;
  50 class BoxLockNode;
  51 class CMoveNode;
  52 class CallDynamicJavaNode;
  53 class CallJavaNode;
  54 class CallLeafNode;
  55 class CallLeafNoFPNode;
  56 class CallNode;
  57 class CallRuntimeNode;
  58 class CallNativeNode;
  59 class CallStaticJavaNode;
  60 class CastFFNode;
  61 class CastDDNode;
  62 class CastVVNode;
  63 class CastIINode;
  64 class CastLLNode;
  65 class CatchNode;
  66 class CatchProjNode;
  67 class CheckCastPPNode;
  68 class ClearArrayNode;
  69 class CmpNode;
  70 class CodeBuffer;
  71 class ConstraintCastNode;
  72 class ConNode;
  73 class CompareAndSwapNode;
  74 class CompareAndExchangeNode;
  75 class CountedLoopNode;
  76 class CountedLoopEndNode;
  77 class DecodeNarrowPtrNode;
  78 class DecodeNNode;
  79 class DecodeNKlassNode;
  80 class EncodeNarrowPtrNode;
  81 class EncodePNode;
  82 class EncodePKlassNode;
  83 class FastLockNode;
  84 class FastUnlockNode;
  85 class HaltNode;
  86 class IfNode;
  87 class IfProjNode;
  88 class IfFalseNode;
  89 class IfTrueNode;
  90 class InitializeNode;
  91 class JVMState;
  92 class JumpNode;
  93 class JumpProjNode;
  94 class LoadNode;
  95 class LoadStoreNode;
  96 class LoadStoreConditionalNode;
  97 class LockNode;
  98 class LongCountedLoopNode;
  99 class LongCountedLoopEndNode;
 100 class LoopNode;
 101 class MachBranchNode;
 102 class MachCallDynamicJavaNode;
 103 class MachCallJavaNode;
 104 class MachCallLeafNode;
 105 class MachCallNode;
 106 class MachCallNativeNode;
 107 class MachCallRuntimeNode;
 108 class MachCallStaticJavaNode;
 109 class MachConstantBaseNode;
 110 class MachConstantNode;
 111 class MachGotoNode;
 112 class MachIfNode;
 113 class MachJumpNode;
 114 class MachNode;
 115 class MachNullCheckNode;
 116 class MachProjNode;
 117 class MachReturnNode;
 118 class MachSafePointNode;
 119 class MachSpillCopyNode;
 120 class MachTempNode;
 121 class MachMergeNode;
 122 class MachMemBarNode;
 123 class Matcher;
 124 class MemBarNode;
 125 class MemBarStoreStoreNode;
 126 class MemNode;
 127 class MergeMemNode;
 128 class MoveNode;
 129 class MulNode;
 130 class MultiNode;
 131 class MultiBranchNode;
 132 class NeverBranchNode;
 133 class Opaque1Node;
 134 class OuterStripMinedLoopNode;
 135 class OuterStripMinedLoopEndNode;
 136 class Node;
 137 class Node_Array;
 138 class Node_List;
 139 class Node_Stack;
 140 class OopMap;
 141 class ParmNode;
 142 class PCTableNode;
 143 class PhaseCCP;
 144 class PhaseGVN;
 145 class PhaseIterGVN;
 146 class PhaseRegAlloc;
 147 class PhaseTransform;
 148 class PhaseValues;
 149 class PhiNode;
 150 class Pipeline;
 151 class ProjNode;
 152 class RangeCheckNode;
 153 class RegMask;
 154 class RegionNode;
 155 class RootNode;
 156 class SafePointNode;
 157 class SafePointScalarObjectNode;
 158 class StartNode;
 159 class State;
 160 class StoreNode;
 161 class SubNode;
 162 class SubTypeCheckNode;
 163 class Type;
 164 class TypeNode;
 165 class UnlockNode;
 166 class VectorNode;
 167 class LoadVectorNode;
 168 class LoadVectorMaskedNode;
 169 class StoreVectorMaskedNode;
 170 class LoadVectorGatherNode;
 171 class StoreVectorNode;
 172 class StoreVectorScatterNode;
 173 class VectorMaskCmpNode;
 174 class VectorUnboxNode;
 175 class VectorSet;
 176 class VectorReinterpretNode;
 177 
 178 // The type of all node counts and indexes.
 179 // It must hold at least 16 bits, but must also be fast to load and store.
 180 // This type, if less than 32 bits, could limit the number of possible nodes.
 181 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 182 typedef unsigned int node_idx_t;
 183 
 184 
 185 #ifndef OPTO_DU_ITERATOR_ASSERT
 186 #ifdef ASSERT
 187 #define OPTO_DU_ITERATOR_ASSERT 1
 188 #else
 189 #define OPTO_DU_ITERATOR_ASSERT 0
 190 #endif
 191 #endif //OPTO_DU_ITERATOR_ASSERT
 192 
 193 #if OPTO_DU_ITERATOR_ASSERT
 194 class DUIterator;
 195 class DUIterator_Fast;
 196 class DUIterator_Last;
 197 #else
 198 typedef uint   DUIterator;
 199 typedef Node** DUIterator_Fast;
 200 typedef Node** DUIterator_Last;
 201 #endif
 202 
 203 // Node Sentinel
 204 #define NodeSentinel (Node*)-1
 205 
 206 // Unknown count frequency
 207 #define COUNT_UNKNOWN (-1.0f)
 208 
 209 //------------------------------Node-------------------------------------------
 210 // Nodes define actions in the program.  They create values, which have types.
 211 // They are both vertices in a directed graph and program primitives.  Nodes
 212 // are labeled; the label is the "opcode", the primitive function in the lambda
 213 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 214 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 215 // the Node's function.  These inputs also define a Type equation for the Node.
 216 // Solving these Type equations amounts to doing dataflow analysis.
 217 // Control and data are uniformly represented in the graph.  Finally, Nodes
 218 // have a unique dense integer index which is used to index into side arrays
 219 // whenever I have phase-specific information.
 220 
 221 class Node {
 222   friend class VMStructs;
 223 
 224   // Lots of restrictions on cloning Nodes
 225   NONCOPYABLE(Node);
 226 
 227 public:
 228   friend class Compile;
 229   #if OPTO_DU_ITERATOR_ASSERT
 230   friend class DUIterator_Common;
 231   friend class DUIterator;
 232   friend class DUIterator_Fast;
 233   friend class DUIterator_Last;
 234   #endif
 235 
 236   // Because Nodes come and go, I define an Arena of Node structures to pull
 237   // from.  This should allow fast access to node creation & deletion.  This
 238   // field is a local cache of a value defined in some "program fragment" for
 239   // which these Nodes are just a part of.
 240 
 241   inline void* operator new(size_t x) throw() {
 242     Compile* C = Compile::current();
 243     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 244     return (void*)n;
 245   }
 246 
 247   // Delete is a NOP
 248   void operator delete( void *ptr ) {}
 249   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 250   void destruct(PhaseValues* phase);
 251 
 252   // Create a new Node.  Required is the number is of inputs required for
 253   // semantic correctness.
 254   Node( uint required );
 255 
 256   // Create a new Node with given input edges.
 257   // This version requires use of the "edge-count" new.
 258   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 259   Node( Node *n0 );
 260   Node( Node *n0, Node *n1 );
 261   Node( Node *n0, Node *n1, Node *n2 );
 262   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 263   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 264   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 265   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 266             Node *n4, Node *n5, Node *n6 );
 267 
 268   // Clone an inherited Node given only the base Node type.
 269   Node* clone() const;
 270 
 271   // Clone a Node, immediately supplying one or two new edges.
 272   // The first and second arguments, if non-null, replace in(1) and in(2),
 273   // respectively.
 274   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 275     Node* nn = clone();
 276     if (in1 != NULL)  nn->set_req(1, in1);
 277     if (in2 != NULL)  nn->set_req(2, in2);
 278     return nn;
 279   }
 280 
 281 private:
 282   // Shared setup for the above constructors.
 283   // Handles all interactions with Compile::current.
 284   // Puts initial values in all Node fields except _idx.
 285   // Returns the initial value for _idx, which cannot
 286   // be initialized by assignment.
 287   inline int Init(int req);
 288 
 289 //----------------- input edge handling
 290 protected:
 291   friend class PhaseCFG;        // Access to address of _in array elements
 292   Node **_in;                   // Array of use-def references to Nodes
 293   Node **_out;                  // Array of def-use references to Nodes
 294 
 295   // Input edges are split into two categories.  Required edges are required
 296   // for semantic correctness; order is important and NULLs are allowed.
 297   // Precedence edges are used to help determine execution order and are
 298   // added, e.g., for scheduling purposes.  They are unordered and not
 299   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 300   // are required, from _cnt to _max-1 are precedence edges.
 301   node_idx_t _cnt;              // Total number of required Node inputs.
 302 
 303   node_idx_t _max;              // Actual length of input array.
 304 
 305   // Output edges are an unordered list of def-use edges which exactly
 306   // correspond to required input edges which point from other nodes
 307   // to this one.  Thus the count of the output edges is the number of
 308   // users of this node.
 309   node_idx_t _outcnt;           // Total number of Node outputs.
 310 
 311   node_idx_t _outmax;           // Actual length of output array.
 312 
 313   // Grow the actual input array to the next larger power-of-2 bigger than len.
 314   void grow( uint len );
 315   // Grow the output array to the next larger power-of-2 bigger than len.
 316   void out_grow( uint len );
 317 
 318  public:
 319   // Each Node is assigned a unique small/dense number.  This number is used
 320   // to index into auxiliary arrays of data and bit vectors.
 321   // The field _idx is declared constant to defend against inadvertent assignments,
 322   // since it is used by clients as a naked field. However, the field's value can be
 323   // changed using the set_idx() method.
 324   //
 325   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 326   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 327   // preserved in _parse_idx.
 328   const node_idx_t _idx;
 329   DEBUG_ONLY(const node_idx_t _parse_idx;)
 330   // IGV node identifier. Two nodes, possibly in different compilation phases,
 331   // have the same IGV identifier if (and only if) they are the very same node
 332   // (same memory address) or one is "derived" from the other (by e.g.
 333   // renumbering or matching). This identifier makes it possible to follow the
 334   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 335   NOT_PRODUCT(node_idx_t _igv_idx;)
 336 
 337   // Get the (read-only) number of input edges
 338   uint req() const { return _cnt; }
 339   uint len() const { return _max; }
 340   // Get the (read-only) number of output edges
 341   uint outcnt() const { return _outcnt; }
 342 
 343 #if OPTO_DU_ITERATOR_ASSERT
 344   // Iterate over the out-edges of this node.  Deletions are illegal.
 345   inline DUIterator outs() const;
 346   // Use this when the out array might have changed to suppress asserts.
 347   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 348   // Does the node have an out at this position?  (Used for iteration.)
 349   inline bool has_out(DUIterator& i) const;
 350   inline Node*    out(DUIterator& i) const;
 351   // Iterate over the out-edges of this node.  All changes are illegal.
 352   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 353   inline Node*    fast_out(DUIterator_Fast& i) const;
 354   // Iterate over the out-edges of this node, deleting one at a time.
 355   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 356   inline Node*    last_out(DUIterator_Last& i) const;
 357   // The inline bodies of all these methods are after the iterator definitions.
 358 #else
 359   // Iterate over the out-edges of this node.  Deletions are illegal.
 360   // This iteration uses integral indexes, to decouple from array reallocations.
 361   DUIterator outs() const  { return 0; }
 362   // Use this when the out array might have changed to suppress asserts.
 363   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 364 
 365   // Reference to the i'th output Node.  Error if out of bounds.
 366   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 367   // Does the node have an out at this position?  (Used for iteration.)
 368   bool has_out(DUIterator i) const { return i < _outcnt; }
 369 
 370   // Iterate over the out-edges of this node.  All changes are illegal.
 371   // This iteration uses a pointer internal to the out array.
 372   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 373     Node** out = _out;
 374     // Assign a limit pointer to the reference argument:
 375     max = out + (ptrdiff_t)_outcnt;
 376     // Return the base pointer:
 377     return out;
 378   }
 379   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 380   // Iterate over the out-edges of this node, deleting one at a time.
 381   // This iteration uses a pointer internal to the out array.
 382   DUIterator_Last last_outs(DUIterator_Last& min) const {
 383     Node** out = _out;
 384     // Assign a limit pointer to the reference argument:
 385     min = out;
 386     // Return the pointer to the start of the iteration:
 387     return out + (ptrdiff_t)_outcnt - 1;
 388   }
 389   Node*    last_out(DUIterator_Last i) const  { return *i; }
 390 #endif
 391 
 392   // Reference to the i'th input Node.  Error if out of bounds.
 393   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 394   // Reference to the i'th input Node.  NULL if out of bounds.
 395   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 396   // Reference to the i'th output Node.  Error if out of bounds.
 397   // Use this accessor sparingly.  We are going trying to use iterators instead.
 398   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 399   // Return the unique out edge.
 400   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 401   // Delete out edge at position 'i' by moving last out edge to position 'i'
 402   void  raw_del_out(uint i) {
 403     assert(i < _outcnt,"oob");
 404     assert(_outcnt > 0,"oob");
 405     #if OPTO_DU_ITERATOR_ASSERT
 406     // Record that a change happened here.
 407     debug_only(_last_del = _out[i]; ++_del_tick);
 408     #endif
 409     _out[i] = _out[--_outcnt];
 410     // Smash the old edge so it can't be used accidentally.
 411     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 412   }
 413 
 414 #ifdef ASSERT
 415   bool is_dead() const;
 416 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 417   bool is_reachable_from_root() const;
 418 #endif
 419   // Check whether node has become unreachable
 420   bool is_unreachable(PhaseIterGVN &igvn) const;
 421 
 422   // Set a required input edge, also updates corresponding output edge
 423   void add_req( Node *n ); // Append a NEW required input
 424   void add_req( Node *n0, Node *n1 ) {
 425     add_req(n0); add_req(n1); }
 426   void add_req( Node *n0, Node *n1, Node *n2 ) {
 427     add_req(n0); add_req(n1); add_req(n2); }
 428   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 429   void del_req( uint idx ); // Delete required edge & compact
 430   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 431   void ins_req( uint i, Node *n ); // Insert a NEW required input
 432   void set_req( uint i, Node *n ) {
 433     assert( is_not_dead(n), "can not use dead node");
 434     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 435     assert( !VerifyHashTableKeys || _hash_lock == 0,
 436             "remove node from hash table before modifying it");
 437     Node** p = &_in[i];    // cache this._in, across the del_out call
 438     if (*p != NULL)  (*p)->del_out((Node *)this);
 439     (*p) = n;
 440     if (n != NULL)      n->add_out((Node *)this);
 441     Compile::current()->record_modified_node(this);
 442   }
 443   // Light version of set_req() to init inputs after node creation.
 444   void init_req( uint i, Node *n ) {
 445     assert( i == 0 && this == n ||
 446             is_not_dead(n), "can not use dead node");
 447     assert( i < _cnt, "oob");
 448     assert( !VerifyHashTableKeys || _hash_lock == 0,
 449             "remove node from hash table before modifying it");
 450     assert( _in[i] == NULL, "sanity");
 451     _in[i] = n;
 452     if (n != NULL)      n->add_out((Node *)this);
 453     Compile::current()->record_modified_node(this);
 454   }
 455   // Find first occurrence of n among my edges:
 456   int find_edge(Node* n);
 457   int find_prec_edge(Node* n) {
 458     for (uint i = req(); i < len(); i++) {
 459       if (_in[i] == n) return i;
 460       if (_in[i] == NULL) {
 461         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 462         break;
 463       }
 464     }
 465     return -1;
 466   }
 467   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = NULL);
 468   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 469   // NULL out all inputs to eliminate incoming Def-Use edges.
 470   void disconnect_inputs(Compile* C);
 471 
 472   // Quickly, return true if and only if I am Compile::current()->top().
 473   bool is_top() const {
 474     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 475     return (_out == NULL);
 476   }
 477   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 478   void setup_is_top();
 479 
 480   // Strip away casting.  (It is depth-limited.)
 481   Node* uncast(bool keep_deps = false) const;
 482   // Return whether two Nodes are equivalent, after stripping casting.
 483   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 484     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 485   }
 486 
 487   // Find out of current node that matches opcode.
 488   Node* find_out_with(int opcode);
 489   // Return true if the current node has an out that matches opcode.
 490   bool has_out_with(int opcode);
 491   // Return true if the current node has an out that matches any of the opcodes.
 492   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 493 
 494 private:
 495   static Node* uncast_helper(const Node* n, bool keep_deps);
 496 
 497   // Add an output edge to the end of the list
 498   void add_out( Node *n ) {
 499     if (is_top())  return;
 500     if( _outcnt == _outmax ) out_grow(_outcnt);
 501     _out[_outcnt++] = n;
 502   }
 503   // Delete an output edge
 504   void del_out( Node *n ) {
 505     if (is_top())  return;
 506     Node** outp = &_out[_outcnt];
 507     // Find and remove n
 508     do {
 509       assert(outp > _out, "Missing Def-Use edge");
 510     } while (*--outp != n);
 511     *outp = _out[--_outcnt];
 512     // Smash the old edge so it can't be used accidentally.
 513     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 514     // Record that a change happened here.
 515     #if OPTO_DU_ITERATOR_ASSERT
 516     debug_only(_last_del = n; ++_del_tick);
 517     #endif
 518   }
 519   // Close gap after removing edge.
 520   void close_prec_gap_at(uint gap) {
 521     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 522     uint i = gap;
 523     Node *last = NULL;
 524     for (; i < _max-1; ++i) {
 525       Node *next = _in[i+1];
 526       if (next == NULL) break;
 527       last = next;
 528     }
 529     _in[gap] = last; // Move last slot to empty one.
 530     _in[i] = NULL;   // NULL out last slot.
 531   }
 532 
 533 public:
 534   // Globally replace this node by a given new node, updating all uses.
 535   void replace_by(Node* new_node);
 536   // Globally replace this node by a given new node, updating all uses
 537   // and cutting input edges of old node.
 538   void subsume_by(Node* new_node, Compile* c) {
 539     replace_by(new_node);
 540     disconnect_inputs(c);
 541   }
 542   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 543   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 544   // Find the one non-null required input.  RegionNode only
 545   Node *nonnull_req() const;
 546   // Add or remove precedence edges
 547   void add_prec( Node *n );
 548   void rm_prec( uint i );
 549 
 550   // Note: prec(i) will not necessarily point to n if edge already exists.
 551   void set_prec( uint i, Node *n ) {
 552     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 553     assert(is_not_dead(n), "can not use dead node");
 554     assert(i >= _cnt, "not a precedence edge");
 555     // Avoid spec violation: duplicated prec edge.
 556     if (_in[i] == n) return;
 557     if (n == NULL || find_prec_edge(n) != -1) {
 558       rm_prec(i);
 559       return;
 560     }
 561     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 562     _in[i] = n;
 563     n->add_out((Node *)this);
 564   }
 565 
 566   // Set this node's index, used by cisc_version to replace current node
 567   void set_idx(uint new_idx) {
 568     const node_idx_t* ref = &_idx;
 569     *(node_idx_t*)ref = new_idx;
 570   }
 571   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 572   void swap_edges(uint i1, uint i2) {
 573     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 574     // Def-Use info is unchanged
 575     Node* n1 = in(i1);
 576     Node* n2 = in(i2);
 577     _in[i1] = n2;
 578     _in[i2] = n1;
 579     // If this node is in the hash table, make sure it doesn't need a rehash.
 580     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 581   }
 582 
 583   // Iterators over input Nodes for a Node X are written as:
 584   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 585   // NOTE: Required edges can contain embedded NULL pointers.
 586 
 587 //----------------- Other Node Properties
 588 
 589   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 590   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 591   //
 592   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 593   // the type of the node the ID represents; another subset of an ID's bits are reserved
 594   // for the superclasses of the node represented by the ID.
 595   //
 596   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 597   // returns false. A.is_A() returns true.
 598   //
 599   // If two classes, A and B, have the same superclass, a different bit of A's class id
 600   // is reserved for A's type than for B's type. That bit is specified by the third
 601   // parameter in the macro DEFINE_CLASS_ID.
 602   //
 603   // By convention, classes with deeper hierarchy are declared first. Moreover,
 604   // classes with the same hierarchy depth are sorted by usage frequency.
 605   //
 606   // The query method masks the bits to cut off bits of subclasses and then compares
 607   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 608   //
 609   //  Class_MachCall=30, ClassMask_MachCall=31
 610   // 12               8               4               0
 611   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 612   //                                  |   |   |   |
 613   //                                  |   |   |   Bit_Mach=2
 614   //                                  |   |   Bit_MachReturn=4
 615   //                                  |   Bit_MachSafePoint=8
 616   //                                  Bit_MachCall=16
 617   //
 618   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 619   // 12               8               4               0
 620   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 621   //                              |   |   |
 622   //                              |   |   Bit_Region=8
 623   //                              |   Bit_Loop=16
 624   //                              Bit_CountedLoop=32
 625 
 626   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 627   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 628   Class_##cl = Class_##supcl + Bit_##cl , \
 629   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 630 
 631   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 632   // so that its values fit into 32 bits.
 633   enum NodeClasses {
 634     Bit_Node   = 0x00000000,
 635     Class_Node = 0x00000000,
 636     ClassMask_Node = 0xFFFFFFFF,
 637 
 638     DEFINE_CLASS_ID(Multi, Node, 0)
 639       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 640         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 641           DEFINE_CLASS_ID(CallJava,         Call, 0)
 642             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 643             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 644           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 645             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 646               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 647           DEFINE_CLASS_ID(Allocate,         Call, 2)
 648             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 649           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 650             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 651             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 652           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 653           DEFINE_CLASS_ID(CallNative,       Call, 5)
 654       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 655         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 656           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 657           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 658         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 659           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 660             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 661             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 662           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 663           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 664         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 665       DEFINE_CLASS_ID(Start,       Multi, 2)
 666       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 667         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 668         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 669 
 670     DEFINE_CLASS_ID(Mach,  Node, 1)
 671       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 672         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 673           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 674             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 675               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 676               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 677             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 678               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 679             DEFINE_CLASS_ID(MachCallNative,       MachCall, 2)
 680       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 681         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 682         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 683         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 684       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 685       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 686       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 687       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 688         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 689       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 690       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 691 
 692     DEFINE_CLASS_ID(Type,  Node, 2)
 693       DEFINE_CLASS_ID(Phi,   Type, 0)
 694       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 695         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 696         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 697         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 698         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 699         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 700         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 701       DEFINE_CLASS_ID(CMove, Type, 3)
 702       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 703       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 704         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 705         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 706       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 707         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 708         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 709       DEFINE_CLASS_ID(Vector, Type, 7)
 710         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 711         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 712         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 713 
 714     DEFINE_CLASS_ID(Proj,  Node, 3)
 715       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 716       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 717       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 718         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 719         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 720       DEFINE_CLASS_ID(Parm,      Proj, 4)
 721       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 722 
 723     DEFINE_CLASS_ID(Mem, Node, 4)
 724       DEFINE_CLASS_ID(Load, Mem, 0)
 725         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 726           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 727           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 1)
 728       DEFINE_CLASS_ID(Store, Mem, 1)
 729         DEFINE_CLASS_ID(StoreVector, Store, 0)
 730           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 731           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 1)
 732       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 733         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 734           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 735         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 736 
 737     DEFINE_CLASS_ID(Region, Node, 5)
 738       DEFINE_CLASS_ID(Loop, Region, 0)
 739         DEFINE_CLASS_ID(Root,                Loop, 0)
 740         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 741           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 742           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 743         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 744 
 745     DEFINE_CLASS_ID(Sub,   Node, 6)
 746       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 747         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 748         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 749         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 750 
 751     DEFINE_CLASS_ID(MergeMem, Node, 7)
 752     DEFINE_CLASS_ID(Bool,     Node, 8)
 753     DEFINE_CLASS_ID(AddP,     Node, 9)
 754     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 755     DEFINE_CLASS_ID(Add,      Node, 11)
 756     DEFINE_CLASS_ID(Mul,      Node, 12)
 757     DEFINE_CLASS_ID(ClearArray, Node, 14)
 758     DEFINE_CLASS_ID(Halt,     Node, 15)
 759     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 760     DEFINE_CLASS_ID(Move,     Node, 17)
 761 
 762     _max_classes  = ClassMask_Move
 763   };
 764   #undef DEFINE_CLASS_ID
 765 
 766   // Flags are sorted by usage frequency.
 767   enum NodeFlags {
 768     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 769     Flag_rematerialize               = 1 << 1,
 770     Flag_needs_anti_dependence_check = 1 << 2,
 771     Flag_is_macro                    = 1 << 3,
 772     Flag_is_Con                      = 1 << 4,
 773     Flag_is_cisc_alternate           = 1 << 5,
 774     Flag_is_dead_loop_safe           = 1 << 6,
 775     Flag_may_be_short_branch         = 1 << 7,
 776     Flag_avoid_back_to_back_before   = 1 << 8,
 777     Flag_avoid_back_to_back_after    = 1 << 9,
 778     Flag_has_call                    = 1 << 10,
 779     Flag_is_reduction                = 1 << 11,
 780     Flag_is_scheduled                = 1 << 12,
 781     Flag_has_vector_mask_set         = 1 << 13,
 782     Flag_is_expensive                = 1 << 14,
 783     Flag_is_predicated_vector        = 1 << 15,
 784     Flag_for_post_loop_opts_igvn     = 1 << 16,
 785     _last_flag                       = Flag_for_post_loop_opts_igvn
 786   };
 787 
 788   class PD;
 789 
 790 private:
 791   juint _class_id;
 792   juint _flags;
 793 
 794   static juint max_flags();
 795 
 796 protected:
 797   // These methods should be called from constructors only.
 798   void init_class_id(juint c) {
 799     _class_id = c; // cast out const
 800   }
 801   void init_flags(uint fl) {
 802     assert(fl <= max_flags(), "invalid node flag");
 803     _flags |= fl;
 804   }
 805   void clear_flag(uint fl) {
 806     assert(fl <= max_flags(), "invalid node flag");
 807     _flags &= ~fl;
 808   }
 809 
 810 public:
 811   const juint class_id() const { return _class_id; }
 812 
 813   const juint flags() const { return _flags; }
 814 
 815   void add_flag(juint fl) { init_flags(fl); }
 816 
 817   void remove_flag(juint fl) { clear_flag(fl); }
 818 
 819   // Return a dense integer opcode number
 820   virtual int Opcode() const;
 821 
 822   // Virtual inherited Node size
 823   virtual uint size_of() const;
 824 
 825   // Other interesting Node properties
 826   #define DEFINE_CLASS_QUERY(type)                           \
 827   bool is_##type() const {                                   \
 828     return ((_class_id & ClassMask_##type) == Class_##type); \
 829   }                                                          \
 830   type##Node *as_##type() const {                            \
 831     assert(is_##type(), "invalid node class: %s", Name()); \
 832     return (type##Node*)this;                                \
 833   }                                                          \
 834   type##Node* isa_##type() const {                           \
 835     return (is_##type()) ? as_##type() : NULL;               \
 836   }
 837 
 838   DEFINE_CLASS_QUERY(AbstractLock)
 839   DEFINE_CLASS_QUERY(Add)
 840   DEFINE_CLASS_QUERY(AddP)
 841   DEFINE_CLASS_QUERY(Allocate)
 842   DEFINE_CLASS_QUERY(AllocateArray)
 843   DEFINE_CLASS_QUERY(ArrayCopy)
 844   DEFINE_CLASS_QUERY(BaseCountedLoop)
 845   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 846   DEFINE_CLASS_QUERY(Bool)
 847   DEFINE_CLASS_QUERY(BoxLock)
 848   DEFINE_CLASS_QUERY(Call)
 849   DEFINE_CLASS_QUERY(CallNative)
 850   DEFINE_CLASS_QUERY(CallDynamicJava)
 851   DEFINE_CLASS_QUERY(CallJava)
 852   DEFINE_CLASS_QUERY(CallLeaf)
 853   DEFINE_CLASS_QUERY(CallLeafNoFP)
 854   DEFINE_CLASS_QUERY(CallRuntime)
 855   DEFINE_CLASS_QUERY(CallStaticJava)
 856   DEFINE_CLASS_QUERY(Catch)
 857   DEFINE_CLASS_QUERY(CatchProj)
 858   DEFINE_CLASS_QUERY(CheckCastPP)
 859   DEFINE_CLASS_QUERY(CastII)
 860   DEFINE_CLASS_QUERY(CastLL)
 861   DEFINE_CLASS_QUERY(ConstraintCast)
 862   DEFINE_CLASS_QUERY(ClearArray)
 863   DEFINE_CLASS_QUERY(CMove)
 864   DEFINE_CLASS_QUERY(Cmp)
 865   DEFINE_CLASS_QUERY(CountedLoop)
 866   DEFINE_CLASS_QUERY(CountedLoopEnd)
 867   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 868   DEFINE_CLASS_QUERY(DecodeN)
 869   DEFINE_CLASS_QUERY(DecodeNKlass)
 870   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 871   DEFINE_CLASS_QUERY(EncodeP)
 872   DEFINE_CLASS_QUERY(EncodePKlass)
 873   DEFINE_CLASS_QUERY(FastLock)
 874   DEFINE_CLASS_QUERY(FastUnlock)
 875   DEFINE_CLASS_QUERY(Halt)
 876   DEFINE_CLASS_QUERY(If)
 877   DEFINE_CLASS_QUERY(RangeCheck)
 878   DEFINE_CLASS_QUERY(IfProj)
 879   DEFINE_CLASS_QUERY(IfFalse)
 880   DEFINE_CLASS_QUERY(IfTrue)
 881   DEFINE_CLASS_QUERY(Initialize)
 882   DEFINE_CLASS_QUERY(Jump)
 883   DEFINE_CLASS_QUERY(JumpProj)
 884   DEFINE_CLASS_QUERY(LongCountedLoop)
 885   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 886   DEFINE_CLASS_QUERY(Load)
 887   DEFINE_CLASS_QUERY(LoadStore)
 888   DEFINE_CLASS_QUERY(LoadStoreConditional)
 889   DEFINE_CLASS_QUERY(Lock)
 890   DEFINE_CLASS_QUERY(Loop)
 891   DEFINE_CLASS_QUERY(Mach)
 892   DEFINE_CLASS_QUERY(MachBranch)
 893   DEFINE_CLASS_QUERY(MachCall)
 894   DEFINE_CLASS_QUERY(MachCallNative)
 895   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 896   DEFINE_CLASS_QUERY(MachCallJava)
 897   DEFINE_CLASS_QUERY(MachCallLeaf)
 898   DEFINE_CLASS_QUERY(MachCallRuntime)
 899   DEFINE_CLASS_QUERY(MachCallStaticJava)
 900   DEFINE_CLASS_QUERY(MachConstantBase)
 901   DEFINE_CLASS_QUERY(MachConstant)
 902   DEFINE_CLASS_QUERY(MachGoto)
 903   DEFINE_CLASS_QUERY(MachIf)
 904   DEFINE_CLASS_QUERY(MachJump)
 905   DEFINE_CLASS_QUERY(MachNullCheck)
 906   DEFINE_CLASS_QUERY(MachProj)
 907   DEFINE_CLASS_QUERY(MachReturn)
 908   DEFINE_CLASS_QUERY(MachSafePoint)
 909   DEFINE_CLASS_QUERY(MachSpillCopy)
 910   DEFINE_CLASS_QUERY(MachTemp)
 911   DEFINE_CLASS_QUERY(MachMemBar)
 912   DEFINE_CLASS_QUERY(MachMerge)
 913   DEFINE_CLASS_QUERY(Mem)
 914   DEFINE_CLASS_QUERY(MemBar)
 915   DEFINE_CLASS_QUERY(MemBarStoreStore)
 916   DEFINE_CLASS_QUERY(MergeMem)
 917   DEFINE_CLASS_QUERY(Move)
 918   DEFINE_CLASS_QUERY(Mul)
 919   DEFINE_CLASS_QUERY(Multi)
 920   DEFINE_CLASS_QUERY(MultiBranch)
 921   DEFINE_CLASS_QUERY(Opaque1)
 922   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 923   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 924   DEFINE_CLASS_QUERY(Parm)
 925   DEFINE_CLASS_QUERY(PCTable)
 926   DEFINE_CLASS_QUERY(Phi)
 927   DEFINE_CLASS_QUERY(Proj)
 928   DEFINE_CLASS_QUERY(Region)
 929   DEFINE_CLASS_QUERY(Root)
 930   DEFINE_CLASS_QUERY(SafePoint)
 931   DEFINE_CLASS_QUERY(SafePointScalarObject)
 932   DEFINE_CLASS_QUERY(Start)
 933   DEFINE_CLASS_QUERY(Store)
 934   DEFINE_CLASS_QUERY(Sub)
 935   DEFINE_CLASS_QUERY(SubTypeCheck)
 936   DEFINE_CLASS_QUERY(Type)
 937   DEFINE_CLASS_QUERY(Vector)
 938   DEFINE_CLASS_QUERY(VectorMaskCmp)
 939   DEFINE_CLASS_QUERY(VectorUnbox)
 940   DEFINE_CLASS_QUERY(VectorReinterpret);
 941   DEFINE_CLASS_QUERY(LoadVector)
 942   DEFINE_CLASS_QUERY(LoadVectorGather)
 943   DEFINE_CLASS_QUERY(StoreVector)
 944   DEFINE_CLASS_QUERY(StoreVectorScatter)
 945   DEFINE_CLASS_QUERY(Unlock)
 946 
 947   #undef DEFINE_CLASS_QUERY
 948 
 949   // duplicate of is_MachSpillCopy()
 950   bool is_SpillCopy () const {
 951     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 952   }
 953 
 954   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 955   // The data node which is safe to leave in dead loop during IGVN optimization.
 956   bool is_dead_loop_safe() const;
 957 
 958   // is_Copy() returns copied edge index (0 or 1)
 959   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 960 
 961   virtual bool is_CFG() const { return false; }
 962 
 963   // If this node is control-dependent on a test, can it be
 964   // rerouted to a dominating equivalent test?  This is usually
 965   // true of non-CFG nodes, but can be false for operations which
 966   // depend for their correct sequencing on more than one test.
 967   // (In that case, hoisting to a dominating test may silently
 968   // skip some other important test.)
 969   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 970 
 971   // When building basic blocks, I need to have a notion of block beginning
 972   // Nodes, next block selector Nodes (block enders), and next block
 973   // projections.  These calls need to work on their machine equivalents.  The
 974   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 975   bool is_block_start() const {
 976     if ( is_Region() )
 977       return this == (const Node*)in(0);
 978     else
 979       return is_Start();
 980   }
 981 
 982   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 983   // Goto and Return.  This call also returns the block ending Node.
 984   virtual const Node *is_block_proj() const;
 985 
 986   // The node is a "macro" node which needs to be expanded before matching
 987   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 988   // The node is expensive: the best control is set during loop opts
 989   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 990 
 991   // An arithmetic node which accumulates a data in a loop.
 992   // It must have the loop's phi as input and provide a def to the phi.
 993   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 994 
 995   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
 996 
 997   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
 998   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
 999 
1000   // Used in lcm to mark nodes that have scheduled
1001   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1002 
1003   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1004 
1005 //----------------- Optimization
1006 
1007   // Get the worst-case Type output for this Node.
1008   virtual const class Type *bottom_type() const;
1009 
1010   // If we find a better type for a node, try to record it permanently.
1011   // Return true if this node actually changed.
1012   // Be sure to do the hash_delete game in the "rehash" variant.
1013   void raise_bottom_type(const Type* new_type);
1014 
1015   // Get the address type with which this node uses and/or defs memory,
1016   // or NULL if none.  The address type is conservatively wide.
1017   // Returns non-null for calls, membars, loads, stores, etc.
1018   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1019   virtual const class TypePtr *adr_type() const { return NULL; }
1020 
1021   // Return an existing node which computes the same function as this node.
1022   // The optimistic combined algorithm requires this to return a Node which
1023   // is a small number of steps away (e.g., one of my inputs).
1024   virtual Node* Identity(PhaseGVN* phase);
1025 
1026   // Return the set of values this Node can take on at runtime.
1027   virtual const Type* Value(PhaseGVN* phase) const;
1028 
1029   // Return a node which is more "ideal" than the current node.
1030   // The invariants on this call are subtle.  If in doubt, read the
1031   // treatise in node.cpp above the default implemention AND TEST WITH
1032   // +VerifyIterativeGVN!
1033   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1034 
1035   // Some nodes have specific Ideal subgraph transformations only if they are
1036   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1037   // for the transformations to happen.
1038   bool has_special_unique_user() const;
1039 
1040   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1041   Node* find_exact_control(Node* ctrl);
1042 
1043   // Check if 'this' node dominates or equal to 'sub'.
1044   bool dominates(Node* sub, Node_List &nlist);
1045 
1046 protected:
1047   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1048 public:
1049 
1050   // See if there is valid pipeline info
1051   static  const Pipeline *pipeline_class();
1052   virtual const Pipeline *pipeline() const;
1053 
1054   // Compute the latency from the def to this instruction of the ith input node
1055   uint latency(uint i);
1056 
1057   // Hash & compare functions, for pessimistic value numbering
1058 
1059   // If the hash function returns the special sentinel value NO_HASH,
1060   // the node is guaranteed never to compare equal to any other node.
1061   // If we accidentally generate a hash with value NO_HASH the node
1062   // won't go into the table and we'll lose a little optimization.
1063   static const uint NO_HASH = 0;
1064   virtual uint hash() const;
1065   virtual bool cmp( const Node &n ) const;
1066 
1067   // Operation appears to be iteratively computed (such as an induction variable)
1068   // It is possible for this operation to return false for a loop-varying
1069   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1070   bool is_iteratively_computed();
1071 
1072   // Determine if a node is a counted loop induction variable.
1073   // NOTE: The method is defined in "loopnode.cpp".
1074   bool is_cloop_ind_var() const;
1075 
1076   // Return a node with opcode "opc" and same inputs as "this" if one can
1077   // be found; Otherwise return NULL;
1078   Node* find_similar(int opc);
1079 
1080   // Return the unique control out if only one. Null if none or more than one.
1081   Node* unique_ctrl_out() const;
1082 
1083   // Set control or add control as precedence edge
1084   void ensure_control_or_add_prec(Node* c);
1085 
1086 //----------------- Code Generation
1087 
1088   // Ideal register class for Matching.  Zero means unmatched instruction
1089   // (these are cloned instead of converted to machine nodes).
1090   virtual uint ideal_reg() const;
1091 
1092   static const uint NotAMachineReg;   // must be > max. machine register
1093 
1094   // Do we Match on this edge index or not?  Generally false for Control
1095   // and true for everything else.  Weird for calls & returns.
1096   virtual uint match_edge(uint idx) const;
1097 
1098   // Register class output is returned in
1099   virtual const RegMask &out_RegMask() const;
1100   // Register class input is expected in
1101   virtual const RegMask &in_RegMask(uint) const;
1102   // Should we clone rather than spill this instruction?
1103   bool rematerialize() const;
1104 
1105   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1106   virtual JVMState* jvms() const;
1107 
1108   // Print as assembly
1109   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1110   // Emit bytes starting at parameter 'ptr'
1111   // Bump 'ptr' by the number of output bytes
1112   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1113   // Size of instruction in bytes
1114   virtual uint size(PhaseRegAlloc *ra_) const;
1115 
1116   // Convenience function to extract an integer constant from a node.
1117   // If it is not an integer constant (either Con, CastII, or Mach),
1118   // return value_if_unknown.
1119   jint find_int_con(jint value_if_unknown) const {
1120     const TypeInt* t = find_int_type();
1121     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1122   }
1123   // Return the constant, knowing it is an integer constant already
1124   jint get_int() const {
1125     const TypeInt* t = find_int_type();
1126     guarantee(t != NULL, "must be con");
1127     return t->get_con();
1128   }
1129   // Here's where the work is done.  Can produce non-constant int types too.
1130   const TypeInt* find_int_type() const;
1131   const TypeInteger* find_integer_type(BasicType bt) const;
1132 
1133   // Same thing for long (and intptr_t, via type.hpp):
1134   jlong get_long() const {
1135     const TypeLong* t = find_long_type();
1136     guarantee(t != NULL, "must be con");
1137     return t->get_con();
1138   }
1139   jlong find_long_con(jint value_if_unknown) const {
1140     const TypeLong* t = find_long_type();
1141     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1142   }
1143   const TypeLong* find_long_type() const;
1144 
1145   jlong get_integer_as_long(BasicType bt) const {
1146     const TypeInteger* t = find_integer_type(bt);
1147     guarantee(t != NULL, "must be con");
1148     return t->get_con_as_long(bt);
1149   }
1150   const TypePtr* get_ptr_type() const;
1151 
1152   // These guys are called by code generated by ADLC:
1153   intptr_t get_ptr() const;
1154   intptr_t get_narrowcon() const;
1155   jdouble getd() const;
1156   jfloat getf() const;
1157 
1158   // Nodes which are pinned into basic blocks
1159   virtual bool pinned() const { return false; }
1160 
1161   // Nodes which use memory without consuming it, hence need antidependences
1162   // More specifically, needs_anti_dependence_check returns true iff the node
1163   // (a) does a load, and (b) does not perform a store (except perhaps to a
1164   // stack slot or some other unaliased location).
1165   bool needs_anti_dependence_check() const;
1166 
1167   // Return which operand this instruction may cisc-spill. In other words,
1168   // return operand position that can convert from reg to memory access
1169   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1170   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1171 
1172   // Whether this is a memory-writing machine node.
1173   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1174 
1175 //----------------- Printing, etc
1176 #ifndef PRODUCT
1177  private:
1178   int _indent;
1179 
1180  public:
1181   void set_indent(int indent) { _indent = indent; }
1182 
1183  private:
1184   static bool add_to_worklist(Node* n, Node_List* worklist, Arena* old_arena, VectorSet* old_space, VectorSet* new_space);
1185 public:
1186   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1187   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1188   void dump() const { dump("\n"); }  // Print this node.
1189   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1190   void dump(int depth) const;        // Print this node, recursively to depth d
1191   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1192   void dump_comp() const;            // Print this node in compact representation.
1193   // Print this node in compact representation.
1194   void dump_comp(const char* suffix, outputStream *st = tty) const;
1195   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1196   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1197   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1198   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1199   // Print compact per-node info
1200   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1201   void dump_related() const;             // Print related nodes (depends on node at hand).
1202   // Print related nodes up to given depths for input and output nodes.
1203   void dump_related(uint d_in, uint d_out) const;
1204   void dump_related_compact() const;     // Print related nodes in compact representation.
1205   // Collect related nodes.
1206   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1207   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1208   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1209 
1210   // Node collectors, to be used in implementations of Node::rel().
1211   // Collect the entire data input graph. Include control inputs if requested.
1212   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1213   // Collect the entire control input graph. Include data inputs if requested.
1214   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1215   // Collect the entire output graph until hitting and including control nodes.
1216   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1217 
1218   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1219   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1220 
1221   // This call defines a class-unique string used to identify class instances
1222   virtual const char *Name() const;
1223 
1224   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1225   // RegMask Print Functions
1226   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1227   void dump_out_regmask() { out_RegMask().dump(); }
1228   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1229   void fast_dump() const {
1230     tty->print("%4d: %-17s", _idx, Name());
1231     for (uint i = 0; i < len(); i++)
1232       if (in(i))
1233         tty->print(" %4d", in(i)->_idx);
1234       else
1235         tty->print(" NULL");
1236     tty->print("\n");
1237   }
1238 #endif
1239 #ifdef ASSERT
1240   void verify_construction();
1241   bool verify_jvms(const JVMState* jvms) const;
1242   int  _debug_idx;                     // Unique value assigned to every node.
1243   int   debug_idx() const              { return _debug_idx; }
1244   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1245 
1246   Node* _debug_orig;                   // Original version of this, if any.
1247   Node*  debug_orig() const            { return _debug_orig; }
1248   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1249   void   dump_orig(outputStream *st, bool print_key = true) const;
1250 
1251   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1252   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1253   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1254 
1255   static void init_NodeProperty();
1256 
1257   #if OPTO_DU_ITERATOR_ASSERT
1258   const Node* _last_del;               // The last deleted node.
1259   uint        _del_tick;               // Bumped when a deletion happens..
1260   #endif
1261 #endif
1262 public:
1263   virtual bool operates_on(BasicType bt, bool signed_int) const {
1264     assert(bt == T_INT || bt == T_LONG, "unsupported");
1265     Unimplemented();
1266     return false;
1267   }
1268 };
1269 
1270 inline bool not_a_node(const Node* n) {
1271   if (n == NULL)                   return true;
1272   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1273   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1274   return false;
1275 }
1276 
1277 //-----------------------------------------------------------------------------
1278 // Iterators over DU info, and associated Node functions.
1279 
1280 #if OPTO_DU_ITERATOR_ASSERT
1281 
1282 // Common code for assertion checking on DU iterators.
1283 class DUIterator_Common {
1284 #ifdef ASSERT
1285  protected:
1286   bool         _vdui;               // cached value of VerifyDUIterators
1287   const Node*  _node;               // the node containing the _out array
1288   uint         _outcnt;             // cached node->_outcnt
1289   uint         _del_tick;           // cached node->_del_tick
1290   Node*        _last;               // last value produced by the iterator
1291 
1292   void sample(const Node* node);    // used by c'tor to set up for verifies
1293   void verify(const Node* node, bool at_end_ok = false);
1294   void verify_resync();
1295   void reset(const DUIterator_Common& that);
1296 
1297 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1298   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1299 #else
1300   #define I_VDUI_ONLY(i,x) { }
1301 #endif //ASSERT
1302 };
1303 
1304 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1305 
1306 // Default DU iterator.  Allows appends onto the out array.
1307 // Allows deletion from the out array only at the current point.
1308 // Usage:
1309 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1310 //    Node* y = x->out(i);
1311 //    ...
1312 //  }
1313 // Compiles in product mode to a unsigned integer index, which indexes
1314 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1315 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1316 // before continuing the loop.  You must delete only the last-produced
1317 // edge.  You must delete only a single copy of the last-produced edge,
1318 // or else you must delete all copies at once (the first time the edge
1319 // is produced by the iterator).
1320 class DUIterator : public DUIterator_Common {
1321   friend class Node;
1322 
1323   // This is the index which provides the product-mode behavior.
1324   // Whatever the product-mode version of the system does to the
1325   // DUI index is done to this index.  All other fields in
1326   // this class are used only for assertion checking.
1327   uint         _idx;
1328 
1329   #ifdef ASSERT
1330   uint         _refresh_tick;    // Records the refresh activity.
1331 
1332   void sample(const Node* node); // Initialize _refresh_tick etc.
1333   void verify(const Node* node, bool at_end_ok = false);
1334   void verify_increment();       // Verify an increment operation.
1335   void verify_resync();          // Verify that we can back up over a deletion.
1336   void verify_finish();          // Verify that the loop terminated properly.
1337   void refresh();                // Resample verification info.
1338   void reset(const DUIterator& that);  // Resample after assignment.
1339   #endif
1340 
1341   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1342     { _idx = 0;                         debug_only(sample(node)); }
1343 
1344  public:
1345   // initialize to garbage; clear _vdui to disable asserts
1346   DUIterator()
1347     { /*initialize to garbage*/         debug_only(_vdui = false); }
1348 
1349   DUIterator(const DUIterator& that)
1350     { _idx = that._idx;                 debug_only(_vdui = false; reset(that)); }
1351 
1352   void operator++(int dummy_to_specify_postfix_op)
1353     { _idx++;                           VDUI_ONLY(verify_increment()); }
1354 
1355   void operator--()
1356     { VDUI_ONLY(verify_resync());       --_idx; }
1357 
1358   ~DUIterator()
1359     { VDUI_ONLY(verify_finish()); }
1360 
1361   void operator=(const DUIterator& that)
1362     { _idx = that._idx;                 debug_only(reset(that)); }
1363 };
1364 
1365 DUIterator Node::outs() const
1366   { return DUIterator(this, 0); }
1367 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1368   { I_VDUI_ONLY(i, i.refresh());        return i; }
1369 bool Node::has_out(DUIterator& i) const
1370   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1371 Node*    Node::out(DUIterator& i) const
1372   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1373 
1374 
1375 // Faster DU iterator.  Disallows insertions into the out array.
1376 // Allows deletion from the out array only at the current point.
1377 // Usage:
1378 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1379 //    Node* y = x->fast_out(i);
1380 //    ...
1381 //  }
1382 // Compiles in product mode to raw Node** pointer arithmetic, with
1383 // no reloading of pointers from the original node x.  If you delete,
1384 // you must perform "--i; --imax" just before continuing the loop.
1385 // If you delete multiple copies of the same edge, you must decrement
1386 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1387 class DUIterator_Fast : public DUIterator_Common {
1388   friend class Node;
1389   friend class DUIterator_Last;
1390 
1391   // This is the pointer which provides the product-mode behavior.
1392   // Whatever the product-mode version of the system does to the
1393   // DUI pointer is done to this pointer.  All other fields in
1394   // this class are used only for assertion checking.
1395   Node**       _outp;
1396 
1397   #ifdef ASSERT
1398   void verify(const Node* node, bool at_end_ok = false);
1399   void verify_limit();
1400   void verify_resync();
1401   void verify_relimit(uint n);
1402   void reset(const DUIterator_Fast& that);
1403   #endif
1404 
1405   // Note:  offset must be signed, since -1 is sometimes passed
1406   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1407     { _outp = node->_out + offset;      debug_only(sample(node)); }
1408 
1409  public:
1410   // initialize to garbage; clear _vdui to disable asserts
1411   DUIterator_Fast()
1412     { /*initialize to garbage*/         debug_only(_vdui = false); }
1413 
1414   DUIterator_Fast(const DUIterator_Fast& that)
1415     { _outp = that._outp;               debug_only(_vdui = false; reset(that)); }
1416 
1417   void operator++(int dummy_to_specify_postfix_op)
1418     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1419 
1420   void operator--()
1421     { VDUI_ONLY(verify_resync());       --_outp; }
1422 
1423   void operator-=(uint n)   // applied to the limit only
1424     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1425 
1426   bool operator<(DUIterator_Fast& limit) {
1427     I_VDUI_ONLY(*this, this->verify(_node, true));
1428     I_VDUI_ONLY(limit, limit.verify_limit());
1429     return _outp < limit._outp;
1430   }
1431 
1432   void operator=(const DUIterator_Fast& that)
1433     { _outp = that._outp;               debug_only(reset(that)); }
1434 };
1435 
1436 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1437   // Assign a limit pointer to the reference argument:
1438   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1439   // Return the base pointer:
1440   return DUIterator_Fast(this, 0);
1441 }
1442 Node* Node::fast_out(DUIterator_Fast& i) const {
1443   I_VDUI_ONLY(i, i.verify(this));
1444   return debug_only(i._last=) *i._outp;
1445 }
1446 
1447 
1448 // Faster DU iterator.  Requires each successive edge to be removed.
1449 // Does not allow insertion of any edges.
1450 // Usage:
1451 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1452 //    Node* y = x->last_out(i);
1453 //    ...
1454 //  }
1455 // Compiles in product mode to raw Node** pointer arithmetic, with
1456 // no reloading of pointers from the original node x.
1457 class DUIterator_Last : private DUIterator_Fast {
1458   friend class Node;
1459 
1460   #ifdef ASSERT
1461   void verify(const Node* node, bool at_end_ok = false);
1462   void verify_limit();
1463   void verify_step(uint num_edges);
1464   #endif
1465 
1466   // Note:  offset must be signed, since -1 is sometimes passed
1467   DUIterator_Last(const Node* node, ptrdiff_t offset)
1468     : DUIterator_Fast(node, offset) { }
1469 
1470   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1471   void operator<(int)                              {} // do not use
1472 
1473  public:
1474   DUIterator_Last() { }
1475   // initialize to garbage
1476 
1477   DUIterator_Last(const DUIterator_Last& that) = default;
1478 
1479   void operator--()
1480     { _outp--;              VDUI_ONLY(verify_step(1));  }
1481 
1482   void operator-=(uint n)
1483     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1484 
1485   bool operator>=(DUIterator_Last& limit) {
1486     I_VDUI_ONLY(*this, this->verify(_node, true));
1487     I_VDUI_ONLY(limit, limit.verify_limit());
1488     return _outp >= limit._outp;
1489   }
1490 
1491   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1492 };
1493 
1494 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1495   // Assign a limit pointer to the reference argument:
1496   imin = DUIterator_Last(this, 0);
1497   // Return the initial pointer:
1498   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1499 }
1500 Node* Node::last_out(DUIterator_Last& i) const {
1501   I_VDUI_ONLY(i, i.verify(this));
1502   return debug_only(i._last=) *i._outp;
1503 }
1504 
1505 #endif //OPTO_DU_ITERATOR_ASSERT
1506 
1507 #undef I_VDUI_ONLY
1508 #undef VDUI_ONLY
1509 
1510 // An Iterator that truly follows the iterator pattern.  Doesn't
1511 // support deletion but could be made to.
1512 //
1513 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1514 //     Node* m = i.get();
1515 //
1516 class SimpleDUIterator : public StackObj {
1517  private:
1518   Node* node;
1519   DUIterator_Fast i;
1520   DUIterator_Fast imax;
1521  public:
1522   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1523   bool has_next() { return i < imax; }
1524   void next() { i++; }
1525   Node* get() { return node->fast_out(i); }
1526 };
1527 
1528 
1529 //-----------------------------------------------------------------------------
1530 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1531 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1532 // Note that the constructor just zeros things, and since I use Arena
1533 // allocation I do not need a destructor to reclaim storage.
1534 class Node_Array : public ResourceObj {
1535   friend class VMStructs;
1536 protected:
1537   Arena* _a;                    // Arena to allocate in
1538   uint   _max;
1539   Node** _nodes;
1540   void   grow( uint i );        // Grow array node to fit
1541 public:
1542   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1543     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1544     clear();
1545   }
1546 
1547   Node_Array(Node_Array* na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1548   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1549   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1550   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1551   Node** adr() { return _nodes; }
1552   // Extend the mapping: index i maps to Node *n.
1553   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1554   void insert( uint i, Node *n );
1555   void remove( uint i );        // Remove, preserving order
1556   // Clear all entries in _nodes to NULL but keep storage
1557   void clear() {
1558     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1559   }
1560 
1561   uint Size() const { return _max; }
1562   void dump() const;
1563 };
1564 
1565 class Node_List : public Node_Array {
1566   friend class VMStructs;
1567   uint _cnt;
1568 public:
1569   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1570   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1571   bool contains(const Node* n) const {
1572     for (uint e = 0; e < size(); e++) {
1573       if (at(e) == n) return true;
1574     }
1575     return false;
1576   }
1577   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1578   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1579   void push( Node *b ) { map(_cnt++,b); }
1580   void yank( Node *n );         // Find and remove
1581   Node *pop() { return _nodes[--_cnt]; }
1582   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1583   void copy(const Node_List& from) {
1584     if (from._max > _max) {
1585       grow(from._max);
1586     }
1587     _cnt = from._cnt;
1588     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1589   }
1590 
1591   uint size() const { return _cnt; }
1592   void dump() const;
1593   void dump_simple() const;
1594 };
1595 
1596 //------------------------------Unique_Node_List-------------------------------
1597 class Unique_Node_List : public Node_List {
1598   friend class VMStructs;
1599   VectorSet _in_worklist;
1600   uint _clock_index;            // Index in list where to pop from next
1601 public:
1602   Unique_Node_List() : Node_List(), _clock_index(0) {}
1603   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1604 
1605   void remove( Node *n );
1606   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1607   VectorSet& member_set(){ return _in_worklist; }
1608 
1609   void push(Node* b) {
1610     if( !_in_worklist.test_set(b->_idx) )
1611       Node_List::push(b);
1612   }
1613   Node *pop() {
1614     if( _clock_index >= size() ) _clock_index = 0;
1615     Node *b = at(_clock_index);
1616     map( _clock_index, Node_List::pop());
1617     if (size() != 0) _clock_index++; // Always start from 0
1618     _in_worklist.remove(b->_idx);
1619     return b;
1620   }
1621   Node *remove(uint i) {
1622     Node *b = Node_List::at(i);
1623     _in_worklist.remove(b->_idx);
1624     map(i,Node_List::pop());
1625     return b;
1626   }
1627   void yank(Node *n) {
1628     _in_worklist.remove(n->_idx);
1629     Node_List::yank(n);
1630   }
1631   void  clear() {
1632     _in_worklist.clear();        // Discards storage but grows automatically
1633     Node_List::clear();
1634     _clock_index = 0;
1635   }
1636 
1637   // Used after parsing to remove useless nodes before Iterative GVN
1638   void remove_useless_nodes(VectorSet& useful);
1639 
1640   bool contains(const Node* n) const {
1641     fatal("use faster member() instead");
1642     return false;
1643   }
1644 
1645 #ifndef PRODUCT
1646   void print_set() const { _in_worklist.print(); }
1647 #endif
1648 };
1649 
1650 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1651 inline void Compile::record_for_igvn(Node* n) {
1652   _for_igvn->push(n);
1653 }
1654 
1655 //------------------------------Node_Stack-------------------------------------
1656 class Node_Stack {
1657   friend class VMStructs;
1658 protected:
1659   struct INode {
1660     Node *node; // Processed node
1661     uint  indx; // Index of next node's child
1662   };
1663   INode *_inode_top; // tos, stack grows up
1664   INode *_inode_max; // End of _inodes == _inodes + _max
1665   INode *_inodes;    // Array storage for the stack
1666   Arena *_a;         // Arena to allocate in
1667   void grow();
1668 public:
1669   Node_Stack(int size) {
1670     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1671     _a = Thread::current()->resource_area();
1672     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1673     _inode_max = _inodes + max;
1674     _inode_top = _inodes - 1; // stack is empty
1675   }
1676 
1677   Node_Stack(Arena *a, int size) : _a(a) {
1678     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1679     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1680     _inode_max = _inodes + max;
1681     _inode_top = _inodes - 1; // stack is empty
1682   }
1683 
1684   void pop() {
1685     assert(_inode_top >= _inodes, "node stack underflow");
1686     --_inode_top;
1687   }
1688   void push(Node *n, uint i) {
1689     ++_inode_top;
1690     if (_inode_top >= _inode_max) grow();
1691     INode *top = _inode_top; // optimization
1692     top->node = n;
1693     top->indx = i;
1694   }
1695   Node *node() const {
1696     return _inode_top->node;
1697   }
1698   Node* node_at(uint i) const {
1699     assert(_inodes + i <= _inode_top, "in range");
1700     return _inodes[i].node;
1701   }
1702   uint index() const {
1703     return _inode_top->indx;
1704   }
1705   uint index_at(uint i) const {
1706     assert(_inodes + i <= _inode_top, "in range");
1707     return _inodes[i].indx;
1708   }
1709   void set_node(Node *n) {
1710     _inode_top->node = n;
1711   }
1712   void set_index(uint i) {
1713     _inode_top->indx = i;
1714   }
1715   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1716   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1717   bool is_nonempty() const { return (_inode_top >= _inodes); }
1718   bool is_empty() const { return (_inode_top < _inodes); }
1719   void clear() { _inode_top = _inodes - 1; } // retain storage
1720 
1721   // Node_Stack is used to map nodes.
1722   Node* find(uint idx) const;
1723 };
1724 
1725 
1726 //-----------------------------Node_Notes--------------------------------------
1727 // Debugging or profiling annotations loosely and sparsely associated
1728 // with some nodes.  See Compile::node_notes_at for the accessor.
1729 class Node_Notes {
1730   friend class VMStructs;
1731   JVMState* _jvms;
1732 
1733 public:
1734   Node_Notes(JVMState* jvms = NULL) {
1735     _jvms = jvms;
1736   }
1737 
1738   JVMState* jvms()            { return _jvms; }
1739   void  set_jvms(JVMState* x) {        _jvms = x; }
1740 
1741   // True if there is nothing here.
1742   bool is_clear() {
1743     return (_jvms == NULL);
1744   }
1745 
1746   // Make there be nothing here.
1747   void clear() {
1748     _jvms = NULL;
1749   }
1750 
1751   // Make a new, clean node notes.
1752   static Node_Notes* make(Compile* C) {
1753     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1754     nn->clear();
1755     return nn;
1756   }
1757 
1758   Node_Notes* clone(Compile* C) {
1759     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1760     (*nn) = (*this);
1761     return nn;
1762   }
1763 
1764   // Absorb any information from source.
1765   bool update_from(Node_Notes* source) {
1766     bool changed = false;
1767     if (source != NULL) {
1768       if (source->jvms() != NULL) {
1769         set_jvms(source->jvms());
1770         changed = true;
1771       }
1772     }
1773     return changed;
1774   }
1775 };
1776 
1777 // Inlined accessors for Compile::node_nodes that require the preceding class:
1778 inline Node_Notes*
1779 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1780                            int idx, bool can_grow) {
1781   assert(idx >= 0, "oob");
1782   int block_idx = (idx >> _log2_node_notes_block_size);
1783   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1784   if (grow_by >= 0) {
1785     if (!can_grow) return NULL;
1786     grow_node_notes(arr, grow_by + 1);
1787   }
1788   if (arr == NULL) return NULL;
1789   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1790   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1791 }
1792 
1793 inline bool
1794 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1795   if (value == NULL || value->is_clear())
1796     return false;  // nothing to write => write nothing
1797   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1798   assert(loc != NULL, "");
1799   return loc->update_from(value);
1800 }
1801 
1802 
1803 //------------------------------TypeNode---------------------------------------
1804 // Node with a Type constant.
1805 class TypeNode : public Node {
1806 protected:
1807   virtual uint hash() const;    // Check the type
1808   virtual bool cmp( const Node &n ) const;
1809   virtual uint size_of() const; // Size is bigger
1810   const Type* const _type;
1811 public:
1812   void set_type(const Type* t) {
1813     assert(t != NULL, "sanity");
1814     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1815     *(const Type**)&_type = t;   // cast away const-ness
1816     // If this node is in the hash table, make sure it doesn't need a rehash.
1817     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1818   }
1819   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1820   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1821     init_class_id(Class_Type);
1822   }
1823   virtual const Type* Value(PhaseGVN* phase) const;
1824   virtual const Type *bottom_type() const;
1825   virtual       uint  ideal_reg() const;
1826 #ifndef PRODUCT
1827   virtual void dump_spec(outputStream *st) const;
1828   virtual void dump_compact_spec(outputStream *st) const;
1829 #endif
1830 };
1831 
1832 #endif // SHARE_OPTO_NODE_HPP