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 FlatArrayCheckNode;
  86 class HaltNode;
  87 class IfNode;
  88 class IfProjNode;
  89 class IfFalseNode;
  90 class IfTrueNode;
  91 class InitializeNode;
  92 class JVMState;
  93 class JumpNode;
  94 class JumpProjNode;
  95 class LoadNode;
  96 class LoadStoreNode;
  97 class LoadStoreConditionalNode;
  98 class LockNode;
  99 class LongCountedLoopNode;
 100 class LongCountedLoopEndNode;
 101 class LoopNode;
 102 class MachBranchNode;
 103 class MachCallDynamicJavaNode;
 104 class MachCallJavaNode;
 105 class MachCallLeafNode;
 106 class MachCallNode;
 107 class MachCallNativeNode;
 108 class MachCallRuntimeNode;
 109 class MachCallStaticJavaNode;
 110 class MachConstantBaseNode;
 111 class MachConstantNode;
 112 class MachGotoNode;
 113 class MachIfNode;
 114 class MachJumpNode;
 115 class MachNode;
 116 class MachNullCheckNode;
 117 class MachProjNode;
 118 class MachPrologNode;
 119 class MachReturnNode;
 120 class MachSafePointNode;
 121 class MachSpillCopyNode;
 122 class MachTempNode;
 123 class MachMergeNode;
 124 class MachMemBarNode;
 125 class MachVEPNode;
 126 class Matcher;
 127 class MemBarNode;
 128 class MemBarStoreStoreNode;
 129 class MemNode;
 130 class MergeMemNode;
 131 class MoveNode;
 132 class MulNode;
 133 class MultiNode;
 134 class MultiBranchNode;
 135 class NeverBranchNode;
 136 class Opaque1Node;
 137 class OuterStripMinedLoopNode;
 138 class OuterStripMinedLoopEndNode;
 139 class Node;
 140 class Node_Array;
 141 class Node_List;
 142 class Node_Stack;
 143 class OopMap;
 144 class ParmNode;
 145 class PCTableNode;
 146 class PhaseCCP;
 147 class PhaseGVN;
 148 class PhaseIterGVN;
 149 class PhaseRegAlloc;
 150 class PhaseTransform;
 151 class PhaseValues;
 152 class PhiNode;
 153 class Pipeline;
 154 class ProjNode;
 155 class RangeCheckNode;
 156 class RegMask;
 157 class RegionNode;
 158 class RootNode;
 159 class SafePointNode;
 160 class SafePointScalarObjectNode;
 161 class StartNode;
 162 class State;
 163 class StoreNode;
 164 class SubNode;
 165 class SubTypeCheckNode;
 166 class Type;
 167 class TypeNode;
 168 class UnlockNode;
 169 class InlineTypeBaseNode;
 170 class InlineTypeNode;
 171 class InlineTypePtrNode;
 172 class VectorNode;
 173 class LoadVectorNode;
 174 class LoadVectorMaskedNode;
 175 class StoreVectorMaskedNode;
 176 class LoadVectorGatherNode;
 177 class StoreVectorNode;
 178 class StoreVectorScatterNode;
 179 class VectorMaskCmpNode;
 180 class VectorSet;
 181 
 182 // The type of all node counts and indexes.
 183 // It must hold at least 16 bits, but must also be fast to load and store.
 184 // This type, if less than 32 bits, could limit the number of possible nodes.
 185 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 186 typedef unsigned int node_idx_t;
 187 
 188 
 189 #ifndef OPTO_DU_ITERATOR_ASSERT
 190 #ifdef ASSERT
 191 #define OPTO_DU_ITERATOR_ASSERT 1
 192 #else
 193 #define OPTO_DU_ITERATOR_ASSERT 0
 194 #endif
 195 #endif //OPTO_DU_ITERATOR_ASSERT
 196 
 197 #if OPTO_DU_ITERATOR_ASSERT
 198 class DUIterator;
 199 class DUIterator_Fast;
 200 class DUIterator_Last;
 201 #else
 202 typedef uint   DUIterator;
 203 typedef Node** DUIterator_Fast;
 204 typedef Node** DUIterator_Last;
 205 #endif
 206 
 207 // Node Sentinel
 208 #define NodeSentinel (Node*)-1
 209 
 210 // Unknown count frequency
 211 #define COUNT_UNKNOWN (-1.0f)
 212 
 213 //------------------------------Node-------------------------------------------
 214 // Nodes define actions in the program.  They create values, which have types.
 215 // They are both vertices in a directed graph and program primitives.  Nodes
 216 // are labeled; the label is the "opcode", the primitive function in the lambda
 217 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 218 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 219 // the Node's function.  These inputs also define a Type equation for the Node.
 220 // Solving these Type equations amounts to doing dataflow analysis.
 221 // Control and data are uniformly represented in the graph.  Finally, Nodes
 222 // have a unique dense integer index which is used to index into side arrays
 223 // whenever I have phase-specific information.
 224 
 225 class Node {
 226   friend class VMStructs;
 227 
 228   // Lots of restrictions on cloning Nodes
 229   NONCOPYABLE(Node);
 230 
 231 public:
 232   friend class Compile;
 233   #if OPTO_DU_ITERATOR_ASSERT
 234   friend class DUIterator_Common;
 235   friend class DUIterator;
 236   friend class DUIterator_Fast;
 237   friend class DUIterator_Last;
 238   #endif
 239 
 240   // Because Nodes come and go, I define an Arena of Node structures to pull
 241   // from.  This should allow fast access to node creation & deletion.  This
 242   // field is a local cache of a value defined in some "program fragment" for
 243   // which these Nodes are just a part of.
 244 
 245   inline void* operator new(size_t x) throw() {
 246     Compile* C = Compile::current();
 247     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 248     return (void*)n;
 249   }
 250 
 251   // Delete is a NOP
 252   void operator delete( void *ptr ) {}
 253   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 254   void destruct(PhaseValues* phase);
 255 
 256   // Create a new Node.  Required is the number is of inputs required for
 257   // semantic correctness.
 258   Node( uint required );
 259 
 260   // Create a new Node with given input edges.
 261   // This version requires use of the "edge-count" new.
 262   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 263   Node( Node *n0 );
 264   Node( Node *n0, Node *n1 );
 265   Node( Node *n0, Node *n1, Node *n2 );
 266   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 267   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 268   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 269   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 270             Node *n4, Node *n5, Node *n6 );
 271 
 272   // Clone an inherited Node given only the base Node type.
 273   Node* clone() const;
 274 
 275   // Clone a Node, immediately supplying one or two new edges.
 276   // The first and second arguments, if non-null, replace in(1) and in(2),
 277   // respectively.
 278   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 279     Node* nn = clone();
 280     if (in1 != NULL)  nn->set_req(1, in1);
 281     if (in2 != NULL)  nn->set_req(2, in2);
 282     return nn;
 283   }
 284 
 285 private:
 286   // Shared setup for the above constructors.
 287   // Handles all interactions with Compile::current.
 288   // Puts initial values in all Node fields except _idx.
 289   // Returns the initial value for _idx, which cannot
 290   // be initialized by assignment.
 291   inline int Init(int req);
 292 
 293 //----------------- input edge handling
 294 protected:
 295   friend class PhaseCFG;        // Access to address of _in array elements
 296   Node **_in;                   // Array of use-def references to Nodes
 297   Node **_out;                  // Array of def-use references to Nodes
 298 
 299   // Input edges are split into two categories.  Required edges are required
 300   // for semantic correctness; order is important and NULLs are allowed.
 301   // Precedence edges are used to help determine execution order and are
 302   // added, e.g., for scheduling purposes.  They are unordered and not
 303   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 304   // are required, from _cnt to _max-1 are precedence edges.
 305   node_idx_t _cnt;              // Total number of required Node inputs.
 306 
 307   node_idx_t _max;              // Actual length of input array.
 308 
 309   // Output edges are an unordered list of def-use edges which exactly
 310   // correspond to required input edges which point from other nodes
 311   // to this one.  Thus the count of the output edges is the number of
 312   // users of this node.
 313   node_idx_t _outcnt;           // Total number of Node outputs.
 314 
 315   node_idx_t _outmax;           // Actual length of output array.
 316 
 317   // Grow the actual input array to the next larger power-of-2 bigger than len.
 318   void grow( uint len );
 319   // Grow the output array to the next larger power-of-2 bigger than len.
 320   void out_grow( uint len );
 321 
 322  public:
 323   // Each Node is assigned a unique small/dense number.  This number is used
 324   // to index into auxiliary arrays of data and bit vectors.
 325   // The field _idx is declared constant to defend against inadvertent assignments,
 326   // since it is used by clients as a naked field. However, the field's value can be
 327   // changed using the set_idx() method.
 328   //
 329   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 330   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 331   // preserved in _parse_idx.
 332   const node_idx_t _idx;
 333   DEBUG_ONLY(const node_idx_t _parse_idx;)
 334   // IGV node identifier. Two nodes, possibly in different compilation phases,
 335   // have the same IGV identifier if (and only if) they are the very same node
 336   // (same memory address) or one is "derived" from the other (by e.g.
 337   // renumbering or matching). This identifier makes it possible to follow the
 338   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 339   NOT_PRODUCT(node_idx_t _igv_idx;)
 340 
 341   // Get the (read-only) number of input edges
 342   uint req() const { return _cnt; }
 343   uint len() const { return _max; }
 344   // Get the (read-only) number of output edges
 345   uint outcnt() const { return _outcnt; }
 346 
 347 #if OPTO_DU_ITERATOR_ASSERT
 348   // Iterate over the out-edges of this node.  Deletions are illegal.
 349   inline DUIterator outs() const;
 350   // Use this when the out array might have changed to suppress asserts.
 351   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 352   // Does the node have an out at this position?  (Used for iteration.)
 353   inline bool has_out(DUIterator& i) const;
 354   inline Node*    out(DUIterator& i) const;
 355   // Iterate over the out-edges of this node.  All changes are illegal.
 356   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 357   inline Node*    fast_out(DUIterator_Fast& i) const;
 358   // Iterate over the out-edges of this node, deleting one at a time.
 359   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 360   inline Node*    last_out(DUIterator_Last& i) const;
 361   // The inline bodies of all these methods are after the iterator definitions.
 362 #else
 363   // Iterate over the out-edges of this node.  Deletions are illegal.
 364   // This iteration uses integral indexes, to decouple from array reallocations.
 365   DUIterator outs() const  { return 0; }
 366   // Use this when the out array might have changed to suppress asserts.
 367   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 368 
 369   // Reference to the i'th output Node.  Error if out of bounds.
 370   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 371   // Does the node have an out at this position?  (Used for iteration.)
 372   bool has_out(DUIterator i) const { return i < _outcnt; }
 373 
 374   // Iterate over the out-edges of this node.  All changes are illegal.
 375   // This iteration uses a pointer internal to the out array.
 376   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 377     Node** out = _out;
 378     // Assign a limit pointer to the reference argument:
 379     max = out + (ptrdiff_t)_outcnt;
 380     // Return the base pointer:
 381     return out;
 382   }
 383   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 384   // Iterate over the out-edges of this node, deleting one at a time.
 385   // This iteration uses a pointer internal to the out array.
 386   DUIterator_Last last_outs(DUIterator_Last& min) const {
 387     Node** out = _out;
 388     // Assign a limit pointer to the reference argument:
 389     min = out;
 390     // Return the pointer to the start of the iteration:
 391     return out + (ptrdiff_t)_outcnt - 1;
 392   }
 393   Node*    last_out(DUIterator_Last i) const  { return *i; }
 394 #endif
 395 
 396   // Reference to the i'th input Node.  Error if out of bounds.
 397   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 398   // Reference to the i'th input Node.  NULL if out of bounds.
 399   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 400   // Reference to the i'th output Node.  Error if out of bounds.
 401   // Use this accessor sparingly.  We are going trying to use iterators instead.
 402   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 403   // Return the unique out edge.
 404   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 405   // Delete out edge at position 'i' by moving last out edge to position 'i'
 406   void  raw_del_out(uint i) {
 407     assert(i < _outcnt,"oob");
 408     assert(_outcnt > 0,"oob");
 409     #if OPTO_DU_ITERATOR_ASSERT
 410     // Record that a change happened here.
 411     debug_only(_last_del = _out[i]; ++_del_tick);
 412     #endif
 413     _out[i] = _out[--_outcnt];
 414     // Smash the old edge so it can't be used accidentally.
 415     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 416   }
 417 
 418 #ifdef ASSERT
 419   bool is_dead() const;
 420 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 421   bool is_reachable_from_root() const;
 422 #endif
 423   // Check whether node has become unreachable
 424   bool is_unreachable(PhaseIterGVN &igvn) const;
 425 
 426   // Set a required input edge, also updates corresponding output edge
 427   void add_req( Node *n ); // Append a NEW required input
 428   void add_req( Node *n0, Node *n1 ) {
 429     add_req(n0); add_req(n1); }
 430   void add_req( Node *n0, Node *n1, Node *n2 ) {
 431     add_req(n0); add_req(n1); add_req(n2); }
 432   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 433   void del_req( uint idx ); // Delete required edge & compact
 434   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 435   void ins_req( uint i, Node *n ); // Insert a NEW required input
 436   void set_req( uint i, Node *n ) {
 437     assert( is_not_dead(n), "can not use dead node");
 438     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 439     assert( !VerifyHashTableKeys || _hash_lock == 0,
 440             "remove node from hash table before modifying it");
 441     Node** p = &_in[i];    // cache this._in, across the del_out call
 442     if (*p != NULL)  (*p)->del_out((Node *)this);
 443     (*p) = n;
 444     if (n != NULL)      n->add_out((Node *)this);
 445     Compile::current()->record_modified_node(this);
 446   }
 447   // Light version of set_req() to init inputs after node creation.
 448   void init_req( uint i, Node *n ) {
 449     assert( i == 0 && this == n ||
 450             is_not_dead(n), "can not use dead node");
 451     assert( i < _cnt, "oob");
 452     assert( !VerifyHashTableKeys || _hash_lock == 0,
 453             "remove node from hash table before modifying it");
 454     assert( _in[i] == NULL, "sanity");
 455     _in[i] = n;
 456     if (n != NULL)      n->add_out((Node *)this);
 457     Compile::current()->record_modified_node(this);
 458   }
 459   // Find first occurrence of n among my edges:
 460   int find_edge(Node* n);
 461   int find_prec_edge(Node* n) {
 462     for (uint i = req(); i < len(); i++) {
 463       if (_in[i] == n) return i;
 464       if (_in[i] == NULL) {
 465         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 466         break;
 467       }
 468     }
 469     return -1;
 470   }
 471   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = NULL);
 472   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 473   // NULL out all inputs to eliminate incoming Def-Use edges.
 474   void disconnect_inputs(Compile* C);
 475 
 476   // Quickly, return true if and only if I am Compile::current()->top().
 477   bool is_top() const {
 478     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 479     return (_out == NULL);
 480   }
 481   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 482   void setup_is_top();
 483 
 484   // Strip away casting.  (It is depth-limited.)
 485   Node* uncast(bool keep_deps = false) const;
 486   // Return whether two Nodes are equivalent, after stripping casting.
 487   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 488     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 489   }
 490 
 491   // Find out of current node that matches opcode.
 492   Node* find_out_with(int opcode);
 493   // Return true if the current node has an out that matches opcode.
 494   bool has_out_with(int opcode);
 495   // Return true if the current node has an out that matches any of the opcodes.
 496   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 497 
 498 private:
 499   static Node* uncast_helper(const Node* n, bool keep_deps);
 500 
 501   // Add an output edge to the end of the list
 502   void add_out( Node *n ) {
 503     if (is_top())  return;
 504     if( _outcnt == _outmax ) out_grow(_outcnt);
 505     _out[_outcnt++] = n;
 506   }
 507   // Delete an output edge
 508   void del_out( Node *n ) {
 509     if (is_top())  return;
 510     Node** outp = &_out[_outcnt];
 511     // Find and remove n
 512     do {
 513       assert(outp > _out, "Missing Def-Use edge");
 514     } while (*--outp != n);
 515     *outp = _out[--_outcnt];
 516     // Smash the old edge so it can't be used accidentally.
 517     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 518     // Record that a change happened here.
 519     #if OPTO_DU_ITERATOR_ASSERT
 520     debug_only(_last_del = n; ++_del_tick);
 521     #endif
 522   }
 523   // Close gap after removing edge.
 524   void close_prec_gap_at(uint gap) {
 525     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 526     uint i = gap;
 527     Node *last = NULL;
 528     for (; i < _max-1; ++i) {
 529       Node *next = _in[i+1];
 530       if (next == NULL) break;
 531       last = next;
 532     }
 533     _in[gap] = last; // Move last slot to empty one.
 534     _in[i] = NULL;   // NULL out last slot.
 535   }
 536 
 537 public:
 538   // Globally replace this node by a given new node, updating all uses.
 539   void replace_by(Node* new_node);
 540   // Globally replace this node by a given new node, updating all uses
 541   // and cutting input edges of old node.
 542   void subsume_by(Node* new_node, Compile* c) {
 543     replace_by(new_node);
 544     disconnect_inputs(c);
 545   }
 546   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 547   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 548   // Find the one non-null required input.  RegionNode only
 549   Node *nonnull_req() const;
 550   // Add or remove precedence edges
 551   void add_prec( Node *n );
 552   void rm_prec( uint i );
 553 
 554   // Note: prec(i) will not necessarily point to n if edge already exists.
 555   void set_prec( uint i, Node *n ) {
 556     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 557     assert(is_not_dead(n), "can not use dead node");
 558     assert(i >= _cnt, "not a precedence edge");
 559     // Avoid spec violation: duplicated prec edge.
 560     if (_in[i] == n) return;
 561     if (n == NULL || find_prec_edge(n) != -1) {
 562       rm_prec(i);
 563       return;
 564     }
 565     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 566     _in[i] = n;
 567     n->add_out((Node *)this);
 568   }
 569 
 570   // Set this node's index, used by cisc_version to replace current node
 571   void set_idx(uint new_idx) {
 572     const node_idx_t* ref = &_idx;
 573     *(node_idx_t*)ref = new_idx;
 574   }
 575   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 576   void swap_edges(uint i1, uint i2) {
 577     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 578     // Def-Use info is unchanged
 579     Node* n1 = in(i1);
 580     Node* n2 = in(i2);
 581     _in[i1] = n2;
 582     _in[i2] = n1;
 583     // If this node is in the hash table, make sure it doesn't need a rehash.
 584     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 585   }
 586 
 587   // Iterators over input Nodes for a Node X are written as:
 588   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 589   // NOTE: Required edges can contain embedded NULL pointers.
 590 
 591 //----------------- Other Node Properties
 592 
 593   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 594   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 595   //
 596   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 597   // the type of the node the ID represents; another subset of an ID's bits are reserved
 598   // for the superclasses of the node represented by the ID.
 599   //
 600   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 601   // returns false. A.is_A() returns true.
 602   //
 603   // If two classes, A and B, have the same superclass, a different bit of A's class id
 604   // is reserved for A's type than for B's type. That bit is specified by the third
 605   // parameter in the macro DEFINE_CLASS_ID.
 606   //
 607   // By convention, classes with deeper hierarchy are declared first. Moreover,
 608   // classes with the same hierarchy depth are sorted by usage frequency.
 609   //
 610   // The query method masks the bits to cut off bits of subclasses and then compares
 611   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 612   //
 613   //  Class_MachCall=30, ClassMask_MachCall=31
 614   // 12               8               4               0
 615   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 616   //                                  |   |   |   |
 617   //                                  |   |   |   Bit_Mach=2
 618   //                                  |   |   Bit_MachReturn=4
 619   //                                  |   Bit_MachSafePoint=8
 620   //                                  Bit_MachCall=16
 621   //
 622   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 623   // 12               8               4               0
 624   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 625   //                              |   |   |
 626   //                              |   |   Bit_Region=8
 627   //                              |   Bit_Loop=16
 628   //                              Bit_CountedLoop=32
 629 
 630   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 631   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 632   Class_##cl = Class_##supcl + Bit_##cl , \
 633   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 634 
 635   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 636   // so that its values fit into 32 bits.
 637   enum NodeClasses {
 638     Bit_Node   = 0x00000000,
 639     Class_Node = 0x00000000,
 640     ClassMask_Node = 0xFFFFFFFF,
 641 
 642     DEFINE_CLASS_ID(Multi, Node, 0)
 643       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 644         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 645           DEFINE_CLASS_ID(CallJava,         Call, 0)
 646             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 647             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 648           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 649             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 650               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 651           DEFINE_CLASS_ID(Allocate,         Call, 2)
 652             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 653           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 654             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 655             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 656           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 657           DEFINE_CLASS_ID(CallNative,       Call, 5)
 658       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 659         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 660           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 661           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 662         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 663           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 664             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 665             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 666           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 667           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 668         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 669       DEFINE_CLASS_ID(Start,       Multi, 2)
 670       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 671         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 672         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 673         DEFINE_CLASS_ID(Blackhole,        MemBar, 2)
 674 
 675     DEFINE_CLASS_ID(Mach,  Node, 1)
 676       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 677         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 678           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 679             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 680               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 681               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 682             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 683               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 684             DEFINE_CLASS_ID(MachCallNative,       MachCall, 2)
 685       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 686         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 687         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 688         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 689       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 690       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 691       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 692       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 693         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 694       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 695       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 696       DEFINE_CLASS_ID(MachProlog,       Mach, 8)
 697       DEFINE_CLASS_ID(MachVEP,          Mach, 9)
 698 
 699     DEFINE_CLASS_ID(Type,  Node, 2)
 700       DEFINE_CLASS_ID(Phi,   Type, 0)
 701       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 702         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 703         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 704         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 705         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 706         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 707         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 708       DEFINE_CLASS_ID(CMove, Type, 3)
 709       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 710       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 711         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 712         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 713       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 714         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 715         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 716       DEFINE_CLASS_ID(Vector, Type, 7)
 717         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 718       DEFINE_CLASS_ID(InlineTypeBase, Type, 8)
 719         DEFINE_CLASS_ID(InlineType, InlineTypeBase, 0)
 720         DEFINE_CLASS_ID(InlineTypePtr, InlineTypeBase, 1)
 721 
 722     DEFINE_CLASS_ID(Proj,  Node, 3)
 723       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 724       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 725       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 726         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 727         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 728       DEFINE_CLASS_ID(Parm,      Proj, 4)
 729       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 730 
 731     DEFINE_CLASS_ID(Mem, Node, 4)
 732       DEFINE_CLASS_ID(Load, Mem, 0)
 733         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 734           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 735           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 1)
 736       DEFINE_CLASS_ID(Store, Mem, 1)
 737         DEFINE_CLASS_ID(StoreVector, Store, 0)
 738           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 739           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 1)
 740       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 741         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 742           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 743         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 744 
 745     DEFINE_CLASS_ID(Region, Node, 5)
 746       DEFINE_CLASS_ID(Loop, Region, 0)
 747         DEFINE_CLASS_ID(Root,                Loop, 0)
 748         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 749           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 750           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 751         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 752 
 753     DEFINE_CLASS_ID(Sub,   Node, 6)
 754       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 755         DEFINE_CLASS_ID(FastLock,       Cmp, 0)
 756         DEFINE_CLASS_ID(FastUnlock,     Cmp, 1)
 757         DEFINE_CLASS_ID(SubTypeCheck,   Cmp, 2)
 758         DEFINE_CLASS_ID(FlatArrayCheck, Cmp, 3)
 759 
 760     DEFINE_CLASS_ID(MergeMem, Node, 7)
 761     DEFINE_CLASS_ID(Bool,     Node, 8)
 762     DEFINE_CLASS_ID(AddP,     Node, 9)
 763     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 764     DEFINE_CLASS_ID(Add,      Node, 11)
 765     DEFINE_CLASS_ID(Mul,      Node, 12)
 766     DEFINE_CLASS_ID(ClearArray, Node, 14)
 767     DEFINE_CLASS_ID(Halt,     Node, 15)
 768     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 769     DEFINE_CLASS_ID(Move,     Node, 17)
 770 
 771     _max_classes  = ClassMask_Move
 772   };
 773   #undef DEFINE_CLASS_ID
 774 
 775   // Flags are sorted by usage frequency.
 776   enum NodeFlags {
 777     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 778     Flag_rematerialize               = 1 << 1,
 779     Flag_needs_anti_dependence_check = 1 << 2,
 780     Flag_is_macro                    = 1 << 3,
 781     Flag_is_Con                      = 1 << 4,
 782     Flag_is_cisc_alternate           = 1 << 5,
 783     Flag_is_dead_loop_safe           = 1 << 6,
 784     Flag_may_be_short_branch         = 1 << 7,
 785     Flag_avoid_back_to_back_before   = 1 << 8,
 786     Flag_avoid_back_to_back_after    = 1 << 9,
 787     Flag_has_call                    = 1 << 10,
 788     Flag_is_reduction                = 1 << 11,
 789     Flag_is_scheduled                = 1 << 12,
 790     Flag_has_vector_mask_set         = 1 << 13,
 791     Flag_is_expensive                = 1 << 14,
 792     Flag_for_post_loop_opts_igvn     = 1 << 15,
 793     _last_flag                       = Flag_for_post_loop_opts_igvn
 794   };
 795 
 796   class PD;
 797 
 798 private:
 799   juint _class_id;
 800   juint _flags;
 801 
 802   static juint max_flags();
 803 
 804 protected:
 805   // These methods should be called from constructors only.
 806   void init_class_id(juint c) {
 807     _class_id = c; // cast out const
 808   }
 809   void init_flags(uint fl) {
 810     assert(fl <= max_flags(), "invalid node flag");
 811     _flags |= fl;
 812   }
 813   void clear_flag(uint fl) {
 814     assert(fl <= max_flags(), "invalid node flag");
 815     _flags &= ~fl;
 816   }
 817 
 818 public:
 819   const juint class_id() const { return _class_id; }
 820 
 821   const juint flags() const { return _flags; }
 822 
 823   void add_flag(juint fl) { init_flags(fl); }
 824 
 825   void remove_flag(juint fl) { clear_flag(fl); }
 826 
 827   // Return a dense integer opcode number
 828   virtual int Opcode() const;
 829 
 830   // Virtual inherited Node size
 831   virtual uint size_of() const;
 832 
 833   // Other interesting Node properties
 834   #define DEFINE_CLASS_QUERY(type)                           \
 835   bool is_##type() const {                                   \
 836     return ((_class_id & ClassMask_##type) == Class_##type); \
 837   }                                                          \
 838   type##Node *as_##type() const {                            \
 839     assert(is_##type(), "invalid node class: %s", Name()); \
 840     return (type##Node*)this;                                \
 841   }                                                          \
 842   type##Node* isa_##type() const {                           \
 843     return (is_##type()) ? as_##type() : NULL;               \
 844   }
 845 
 846   DEFINE_CLASS_QUERY(AbstractLock)
 847   DEFINE_CLASS_QUERY(Add)
 848   DEFINE_CLASS_QUERY(AddP)
 849   DEFINE_CLASS_QUERY(Allocate)
 850   DEFINE_CLASS_QUERY(AllocateArray)
 851   DEFINE_CLASS_QUERY(ArrayCopy)
 852   DEFINE_CLASS_QUERY(BaseCountedLoop)
 853   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 854   DEFINE_CLASS_QUERY(Blackhole)
 855   DEFINE_CLASS_QUERY(Bool)
 856   DEFINE_CLASS_QUERY(BoxLock)
 857   DEFINE_CLASS_QUERY(Call)
 858   DEFINE_CLASS_QUERY(CallNative)
 859   DEFINE_CLASS_QUERY(CallDynamicJava)
 860   DEFINE_CLASS_QUERY(CallJava)
 861   DEFINE_CLASS_QUERY(CallLeaf)
 862   DEFINE_CLASS_QUERY(CallLeafNoFP)
 863   DEFINE_CLASS_QUERY(CallRuntime)
 864   DEFINE_CLASS_QUERY(CallStaticJava)
 865   DEFINE_CLASS_QUERY(Catch)
 866   DEFINE_CLASS_QUERY(CatchProj)
 867   DEFINE_CLASS_QUERY(CheckCastPP)
 868   DEFINE_CLASS_QUERY(CastII)
 869   DEFINE_CLASS_QUERY(CastLL)
 870   DEFINE_CLASS_QUERY(ConstraintCast)
 871   DEFINE_CLASS_QUERY(ClearArray)
 872   DEFINE_CLASS_QUERY(CMove)
 873   DEFINE_CLASS_QUERY(Cmp)
 874   DEFINE_CLASS_QUERY(CountedLoop)
 875   DEFINE_CLASS_QUERY(CountedLoopEnd)
 876   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 877   DEFINE_CLASS_QUERY(DecodeN)
 878   DEFINE_CLASS_QUERY(DecodeNKlass)
 879   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 880   DEFINE_CLASS_QUERY(EncodeP)
 881   DEFINE_CLASS_QUERY(EncodePKlass)
 882   DEFINE_CLASS_QUERY(FastLock)
 883   DEFINE_CLASS_QUERY(FastUnlock)
 884   DEFINE_CLASS_QUERY(FlatArrayCheck)
 885   DEFINE_CLASS_QUERY(Halt)
 886   DEFINE_CLASS_QUERY(If)
 887   DEFINE_CLASS_QUERY(RangeCheck)
 888   DEFINE_CLASS_QUERY(IfProj)
 889   DEFINE_CLASS_QUERY(IfFalse)
 890   DEFINE_CLASS_QUERY(IfTrue)
 891   DEFINE_CLASS_QUERY(Initialize)
 892   DEFINE_CLASS_QUERY(Jump)
 893   DEFINE_CLASS_QUERY(JumpProj)
 894   DEFINE_CLASS_QUERY(LongCountedLoop)
 895   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 896   DEFINE_CLASS_QUERY(Load)
 897   DEFINE_CLASS_QUERY(LoadStore)
 898   DEFINE_CLASS_QUERY(LoadStoreConditional)
 899   DEFINE_CLASS_QUERY(Lock)
 900   DEFINE_CLASS_QUERY(Loop)
 901   DEFINE_CLASS_QUERY(Mach)
 902   DEFINE_CLASS_QUERY(MachBranch)
 903   DEFINE_CLASS_QUERY(MachCall)
 904   DEFINE_CLASS_QUERY(MachCallNative)
 905   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 906   DEFINE_CLASS_QUERY(MachCallJava)
 907   DEFINE_CLASS_QUERY(MachCallLeaf)
 908   DEFINE_CLASS_QUERY(MachCallRuntime)
 909   DEFINE_CLASS_QUERY(MachCallStaticJava)
 910   DEFINE_CLASS_QUERY(MachConstantBase)
 911   DEFINE_CLASS_QUERY(MachConstant)
 912   DEFINE_CLASS_QUERY(MachGoto)
 913   DEFINE_CLASS_QUERY(MachIf)
 914   DEFINE_CLASS_QUERY(MachJump)
 915   DEFINE_CLASS_QUERY(MachNullCheck)
 916   DEFINE_CLASS_QUERY(MachProj)
 917   DEFINE_CLASS_QUERY(MachProlog)
 918   DEFINE_CLASS_QUERY(MachReturn)
 919   DEFINE_CLASS_QUERY(MachSafePoint)
 920   DEFINE_CLASS_QUERY(MachSpillCopy)
 921   DEFINE_CLASS_QUERY(MachTemp)
 922   DEFINE_CLASS_QUERY(MachMemBar)
 923   DEFINE_CLASS_QUERY(MachMerge)
 924   DEFINE_CLASS_QUERY(MachVEP)
 925   DEFINE_CLASS_QUERY(Mem)
 926   DEFINE_CLASS_QUERY(MemBar)
 927   DEFINE_CLASS_QUERY(MemBarStoreStore)
 928   DEFINE_CLASS_QUERY(MergeMem)
 929   DEFINE_CLASS_QUERY(Move)
 930   DEFINE_CLASS_QUERY(Mul)
 931   DEFINE_CLASS_QUERY(Multi)
 932   DEFINE_CLASS_QUERY(MultiBranch)
 933   DEFINE_CLASS_QUERY(Opaque1)
 934   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 935   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 936   DEFINE_CLASS_QUERY(Parm)
 937   DEFINE_CLASS_QUERY(PCTable)
 938   DEFINE_CLASS_QUERY(Phi)
 939   DEFINE_CLASS_QUERY(Proj)
 940   DEFINE_CLASS_QUERY(Region)
 941   DEFINE_CLASS_QUERY(Root)
 942   DEFINE_CLASS_QUERY(SafePoint)
 943   DEFINE_CLASS_QUERY(SafePointScalarObject)
 944   DEFINE_CLASS_QUERY(Start)
 945   DEFINE_CLASS_QUERY(Store)
 946   DEFINE_CLASS_QUERY(Sub)
 947   DEFINE_CLASS_QUERY(SubTypeCheck)
 948   DEFINE_CLASS_QUERY(Type)
 949   DEFINE_CLASS_QUERY(InlineType)
 950   DEFINE_CLASS_QUERY(InlineTypeBase)
 951   DEFINE_CLASS_QUERY(InlineTypePtr)
 952   DEFINE_CLASS_QUERY(Vector)
 953   DEFINE_CLASS_QUERY(LoadVector)
 954   DEFINE_CLASS_QUERY(LoadVectorGather)
 955   DEFINE_CLASS_QUERY(StoreVector)
 956   DEFINE_CLASS_QUERY(StoreVectorScatter)
 957   DEFINE_CLASS_QUERY(VectorMaskCmp)
 958   DEFINE_CLASS_QUERY(Unlock)
 959 
 960   #undef DEFINE_CLASS_QUERY
 961 
 962   // duplicate of is_MachSpillCopy()
 963   bool is_SpillCopy () const {
 964     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 965   }
 966 
 967   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 968   // The data node which is safe to leave in dead loop during IGVN optimization.
 969   bool is_dead_loop_safe() const;
 970 
 971   // is_Copy() returns copied edge index (0 or 1)
 972   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 973 
 974   virtual bool is_CFG() const { return false; }
 975 
 976   // If this node is control-dependent on a test, can it be
 977   // rerouted to a dominating equivalent test?  This is usually
 978   // true of non-CFG nodes, but can be false for operations which
 979   // depend for their correct sequencing on more than one test.
 980   // (In that case, hoisting to a dominating test may silently
 981   // skip some other important test.)
 982   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 983 
 984   // When building basic blocks, I need to have a notion of block beginning
 985   // Nodes, next block selector Nodes (block enders), and next block
 986   // projections.  These calls need to work on their machine equivalents.  The
 987   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 988   bool is_block_start() const {
 989     if ( is_Region() )
 990       return this == (const Node*)in(0);
 991     else
 992       return is_Start();
 993   }
 994 
 995   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 996   // Goto and Return.  This call also returns the block ending Node.
 997   virtual const Node *is_block_proj() const;
 998 
 999   // The node is a "macro" node which needs to be expanded before matching
1000   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
1001   // The node is expensive: the best control is set during loop opts
1002   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
1003 
1004   // An arithmetic node which accumulates a data in a loop.
1005   // It must have the loop's phi as input and provide a def to the phi.
1006   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
1007 
1008   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
1009   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
1010 
1011   // Used in lcm to mark nodes that have scheduled
1012   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1013 
1014   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1015 
1016 //----------------- Optimization
1017 
1018   // Get the worst-case Type output for this Node.
1019   virtual const class Type *bottom_type() const;
1020 
1021   // If we find a better type for a node, try to record it permanently.
1022   // Return true if this node actually changed.
1023   // Be sure to do the hash_delete game in the "rehash" variant.
1024   void raise_bottom_type(const Type* new_type);
1025 
1026   // Get the address type with which this node uses and/or defs memory,
1027   // or NULL if none.  The address type is conservatively wide.
1028   // Returns non-null for calls, membars, loads, stores, etc.
1029   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1030   virtual const class TypePtr *adr_type() const { return NULL; }
1031 
1032   // Return an existing node which computes the same function as this node.
1033   // The optimistic combined algorithm requires this to return a Node which
1034   // is a small number of steps away (e.g., one of my inputs).
1035   virtual Node* Identity(PhaseGVN* phase);
1036 
1037   // Return the set of values this Node can take on at runtime.
1038   virtual const Type* Value(PhaseGVN* phase) const;
1039 
1040   // Return a node which is more "ideal" than the current node.
1041   // The invariants on this call are subtle.  If in doubt, read the
1042   // treatise in node.cpp above the default implemention AND TEST WITH
1043   // +VerifyIterativeGVN!
1044   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1045 
1046   // Some nodes have specific Ideal subgraph transformations only if they are
1047   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1048   // for the transformations to happen.
1049   bool has_special_unique_user() const;
1050 
1051   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1052   Node* find_exact_control(Node* ctrl);
1053 
1054   // Check if 'this' node dominates or equal to 'sub'.
1055   bool dominates(Node* sub, Node_List &nlist);
1056 
1057 protected:
1058   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1059 public:
1060 
1061   // See if there is valid pipeline info
1062   static  const Pipeline *pipeline_class();
1063   virtual const Pipeline *pipeline() const;
1064 
1065   // Compute the latency from the def to this instruction of the ith input node
1066   uint latency(uint i);
1067 
1068   // Hash & compare functions, for pessimistic value numbering
1069 
1070   // If the hash function returns the special sentinel value NO_HASH,
1071   // the node is guaranteed never to compare equal to any other node.
1072   // If we accidentally generate a hash with value NO_HASH the node
1073   // won't go into the table and we'll lose a little optimization.
1074   static const uint NO_HASH = 0;
1075   virtual uint hash() const;
1076   virtual bool cmp( const Node &n ) const;
1077 
1078   // Operation appears to be iteratively computed (such as an induction variable)
1079   // It is possible for this operation to return false for a loop-varying
1080   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1081   bool is_iteratively_computed();
1082 
1083   // Determine if a node is a counted loop induction variable.
1084   // NOTE: The method is defined in "loopnode.cpp".
1085   bool is_cloop_ind_var() const;
1086 
1087   // Return a node with opcode "opc" and same inputs as "this" if one can
1088   // be found; Otherwise return NULL;
1089   Node* find_similar(int opc);
1090 
1091   // Return the unique control out if only one. Null if none or more than one.
1092   Node* unique_ctrl_out() const;
1093 
1094   // Set control or add control as precedence edge
1095   void ensure_control_or_add_prec(Node* c);
1096 
1097 //----------------- Code Generation
1098 
1099   // Ideal register class for Matching.  Zero means unmatched instruction
1100   // (these are cloned instead of converted to machine nodes).
1101   virtual uint ideal_reg() const;
1102 
1103   static const uint NotAMachineReg;   // must be > max. machine register
1104 
1105   // Do we Match on this edge index or not?  Generally false for Control
1106   // and true for everything else.  Weird for calls & returns.
1107   virtual uint match_edge(uint idx) const;
1108 
1109   // Register class output is returned in
1110   virtual const RegMask &out_RegMask() const;
1111   // Register class input is expected in
1112   virtual const RegMask &in_RegMask(uint) const;
1113   // Should we clone rather than spill this instruction?
1114   bool rematerialize() const;
1115 
1116   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1117   virtual JVMState* jvms() const;
1118 
1119   // Print as assembly
1120   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1121   // Emit bytes starting at parameter 'ptr'
1122   // Bump 'ptr' by the number of output bytes
1123   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1124   // Size of instruction in bytes
1125   virtual uint size(PhaseRegAlloc *ra_) const;
1126 
1127   // Convenience function to extract an integer constant from a node.
1128   // If it is not an integer constant (either Con, CastII, or Mach),
1129   // return value_if_unknown.
1130   jint find_int_con(jint value_if_unknown) const {
1131     const TypeInt* t = find_int_type();
1132     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1133   }
1134   // Return the constant, knowing it is an integer constant already
1135   jint get_int() const {
1136     const TypeInt* t = find_int_type();
1137     guarantee(t != NULL, "must be con");
1138     return t->get_con();
1139   }
1140   // Here's where the work is done.  Can produce non-constant int types too.
1141   const TypeInt* find_int_type() const;
1142   const TypeInteger* find_integer_type(BasicType bt) const;
1143 
1144   // Same thing for long (and intptr_t, via type.hpp):
1145   jlong get_long() const {
1146     const TypeLong* t = find_long_type();
1147     guarantee(t != NULL, "must be con");
1148     return t->get_con();
1149   }
1150   jlong find_long_con(jint value_if_unknown) const {
1151     const TypeLong* t = find_long_type();
1152     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1153   }
1154   const TypeLong* find_long_type() const;
1155 
1156   jlong get_integer_as_long(BasicType bt) const {
1157     const TypeInteger* t = find_integer_type(bt);
1158     guarantee(t != NULL, "must be con");
1159     return t->get_con_as_long(bt);
1160   }
1161   const TypePtr* get_ptr_type() const;
1162 
1163   // These guys are called by code generated by ADLC:
1164   intptr_t get_ptr() const;
1165   intptr_t get_narrowcon() const;
1166   jdouble getd() const;
1167   jfloat getf() const;
1168 
1169   // Nodes which are pinned into basic blocks
1170   virtual bool pinned() const { return false; }
1171 
1172   // Nodes which use memory without consuming it, hence need antidependences
1173   // More specifically, needs_anti_dependence_check returns true iff the node
1174   // (a) does a load, and (b) does not perform a store (except perhaps to a
1175   // stack slot or some other unaliased location).
1176   bool needs_anti_dependence_check() const;
1177 
1178   // Return which operand this instruction may cisc-spill. In other words,
1179   // return operand position that can convert from reg to memory access
1180   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1181   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1182 
1183   // Whether this is a memory-writing machine node.
1184   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1185 
1186 //----------------- Printing, etc
1187 #ifndef PRODUCT
1188  private:
1189   int _indent;
1190 
1191  public:
1192   void set_indent(int indent) { _indent = indent; }
1193 
1194  private:
1195   static bool add_to_worklist(Node* n, Node_List* worklist, Arena* old_arena, VectorSet* old_space, VectorSet* new_space);
1196 public:
1197   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1198   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1199   void dump() const { dump("\n"); }  // Print this node.
1200   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1201   void dump(int depth) const;        // Print this node, recursively to depth d
1202   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1203   void dump_comp() const;            // Print this node in compact representation.
1204   // Print this node in compact representation.
1205   void dump_comp(const char* suffix, outputStream *st = tty) const;
1206   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1207   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1208   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1209   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1210   // Print compact per-node info
1211   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1212   void dump_related() const;             // Print related nodes (depends on node at hand).
1213   // Print related nodes up to given depths for input and output nodes.
1214   void dump_related(uint d_in, uint d_out) const;
1215   void dump_related_compact() const;     // Print related nodes in compact representation.
1216   // Collect related nodes.
1217   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1218   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1219   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1220 
1221   // Node collectors, to be used in implementations of Node::rel().
1222   // Collect the entire data input graph. Include control inputs if requested.
1223   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1224   // Collect the entire control input graph. Include data inputs if requested.
1225   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1226   // Collect the entire output graph until hitting and including control nodes.
1227   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1228 
1229   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1230   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1231 
1232   // This call defines a class-unique string used to identify class instances
1233   virtual const char *Name() const;
1234 
1235   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1236   // RegMask Print Functions
1237   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1238   void dump_out_regmask() { out_RegMask().dump(); }
1239   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1240   void fast_dump() const {
1241     tty->print("%4d: %-17s", _idx, Name());
1242     for (uint i = 0; i < len(); i++)
1243       if (in(i))
1244         tty->print(" %4d", in(i)->_idx);
1245       else
1246         tty->print(" NULL");
1247     tty->print("\n");
1248   }
1249 #endif
1250 #ifdef ASSERT
1251   void verify_construction();
1252   bool verify_jvms(const JVMState* jvms) const;
1253   int  _debug_idx;                     // Unique value assigned to every node.
1254   int   debug_idx() const              { return _debug_idx; }
1255   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1256 
1257   Node* _debug_orig;                   // Original version of this, if any.
1258   Node*  debug_orig() const            { return _debug_orig; }
1259   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1260   void   dump_orig(outputStream *st, bool print_key = true) const;
1261 
1262   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1263   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1264   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1265 
1266   static void init_NodeProperty();
1267 
1268   #if OPTO_DU_ITERATOR_ASSERT
1269   const Node* _last_del;               // The last deleted node.
1270   uint        _del_tick;               // Bumped when a deletion happens..
1271   #endif
1272 #endif
1273 public:
1274   virtual bool operates_on(BasicType bt, bool signed_int) const {
1275     assert(bt == T_INT || bt == T_LONG, "unsupported");
1276     Unimplemented();
1277     return false;
1278   }
1279 };
1280 
1281 inline bool not_a_node(const Node* n) {
1282   if (n == NULL)                   return true;
1283   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1284   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1285   return false;
1286 }
1287 
1288 //-----------------------------------------------------------------------------
1289 // Iterators over DU info, and associated Node functions.
1290 
1291 #if OPTO_DU_ITERATOR_ASSERT
1292 
1293 // Common code for assertion checking on DU iterators.
1294 class DUIterator_Common {
1295 #ifdef ASSERT
1296  protected:
1297   bool         _vdui;               // cached value of VerifyDUIterators
1298   const Node*  _node;               // the node containing the _out array
1299   uint         _outcnt;             // cached node->_outcnt
1300   uint         _del_tick;           // cached node->_del_tick
1301   Node*        _last;               // last value produced by the iterator
1302 
1303   void sample(const Node* node);    // used by c'tor to set up for verifies
1304   void verify(const Node* node, bool at_end_ok = false);
1305   void verify_resync();
1306   void reset(const DUIterator_Common& that);
1307 
1308 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1309   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1310 #else
1311   #define I_VDUI_ONLY(i,x) { }
1312 #endif //ASSERT
1313 };
1314 
1315 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1316 
1317 // Default DU iterator.  Allows appends onto the out array.
1318 // Allows deletion from the out array only at the current point.
1319 // Usage:
1320 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1321 //    Node* y = x->out(i);
1322 //    ...
1323 //  }
1324 // Compiles in product mode to a unsigned integer index, which indexes
1325 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1326 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1327 // before continuing the loop.  You must delete only the last-produced
1328 // edge.  You must delete only a single copy of the last-produced edge,
1329 // or else you must delete all copies at once (the first time the edge
1330 // is produced by the iterator).
1331 class DUIterator : public DUIterator_Common {
1332   friend class Node;
1333 
1334   // This is the index which provides the product-mode behavior.
1335   // Whatever the product-mode version of the system does to the
1336   // DUI index is done to this index.  All other fields in
1337   // this class are used only for assertion checking.
1338   uint         _idx;
1339 
1340   #ifdef ASSERT
1341   uint         _refresh_tick;    // Records the refresh activity.
1342 
1343   void sample(const Node* node); // Initialize _refresh_tick etc.
1344   void verify(const Node* node, bool at_end_ok = false);
1345   void verify_increment();       // Verify an increment operation.
1346   void verify_resync();          // Verify that we can back up over a deletion.
1347   void verify_finish();          // Verify that the loop terminated properly.
1348   void refresh();                // Resample verification info.
1349   void reset(const DUIterator& that);  // Resample after assignment.
1350   #endif
1351 
1352   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1353     { _idx = 0;                         debug_only(sample(node)); }
1354 
1355  public:
1356   // initialize to garbage; clear _vdui to disable asserts
1357   DUIterator()
1358     { /*initialize to garbage*/         debug_only(_vdui = false); }
1359 
1360   DUIterator(const DUIterator& that)
1361     { _idx = that._idx;                 debug_only(_vdui = false; reset(that)); }
1362 
1363   void operator++(int dummy_to_specify_postfix_op)
1364     { _idx++;                           VDUI_ONLY(verify_increment()); }
1365 
1366   void operator--()
1367     { VDUI_ONLY(verify_resync());       --_idx; }
1368 
1369   ~DUIterator()
1370     { VDUI_ONLY(verify_finish()); }
1371 
1372   void operator=(const DUIterator& that)
1373     { _idx = that._idx;                 debug_only(reset(that)); }
1374 };
1375 
1376 DUIterator Node::outs() const
1377   { return DUIterator(this, 0); }
1378 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1379   { I_VDUI_ONLY(i, i.refresh());        return i; }
1380 bool Node::has_out(DUIterator& i) const
1381   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1382 Node*    Node::out(DUIterator& i) const
1383   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1384 
1385 
1386 // Faster DU iterator.  Disallows insertions into the out array.
1387 // Allows deletion from the out array only at the current point.
1388 // Usage:
1389 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1390 //    Node* y = x->fast_out(i);
1391 //    ...
1392 //  }
1393 // Compiles in product mode to raw Node** pointer arithmetic, with
1394 // no reloading of pointers from the original node x.  If you delete,
1395 // you must perform "--i; --imax" just before continuing the loop.
1396 // If you delete multiple copies of the same edge, you must decrement
1397 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1398 class DUIterator_Fast : public DUIterator_Common {
1399   friend class Node;
1400   friend class DUIterator_Last;
1401 
1402   // This is the pointer which provides the product-mode behavior.
1403   // Whatever the product-mode version of the system does to the
1404   // DUI pointer is done to this pointer.  All other fields in
1405   // this class are used only for assertion checking.
1406   Node**       _outp;
1407 
1408   #ifdef ASSERT
1409   void verify(const Node* node, bool at_end_ok = false);
1410   void verify_limit();
1411   void verify_resync();
1412   void verify_relimit(uint n);
1413   void reset(const DUIterator_Fast& that);
1414   #endif
1415 
1416   // Note:  offset must be signed, since -1 is sometimes passed
1417   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1418     { _outp = node->_out + offset;      debug_only(sample(node)); }
1419 
1420  public:
1421   // initialize to garbage; clear _vdui to disable asserts
1422   DUIterator_Fast()
1423     { /*initialize to garbage*/         debug_only(_vdui = false); }
1424 
1425   DUIterator_Fast(const DUIterator_Fast& that)
1426     { _outp = that._outp;               debug_only(_vdui = false; reset(that)); }
1427 
1428   void operator++(int dummy_to_specify_postfix_op)
1429     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1430 
1431   void operator--()
1432     { VDUI_ONLY(verify_resync());       --_outp; }
1433 
1434   void operator-=(uint n)   // applied to the limit only
1435     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1436 
1437   bool operator<(DUIterator_Fast& limit) {
1438     I_VDUI_ONLY(*this, this->verify(_node, true));
1439     I_VDUI_ONLY(limit, limit.verify_limit());
1440     return _outp < limit._outp;
1441   }
1442 
1443   void operator=(const DUIterator_Fast& that)
1444     { _outp = that._outp;               debug_only(reset(that)); }
1445 };
1446 
1447 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1448   // Assign a limit pointer to the reference argument:
1449   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1450   // Return the base pointer:
1451   return DUIterator_Fast(this, 0);
1452 }
1453 Node* Node::fast_out(DUIterator_Fast& i) const {
1454   I_VDUI_ONLY(i, i.verify(this));
1455   return debug_only(i._last=) *i._outp;
1456 }
1457 
1458 
1459 // Faster DU iterator.  Requires each successive edge to be removed.
1460 // Does not allow insertion of any edges.
1461 // Usage:
1462 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1463 //    Node* y = x->last_out(i);
1464 //    ...
1465 //  }
1466 // Compiles in product mode to raw Node** pointer arithmetic, with
1467 // no reloading of pointers from the original node x.
1468 class DUIterator_Last : private DUIterator_Fast {
1469   friend class Node;
1470 
1471   #ifdef ASSERT
1472   void verify(const Node* node, bool at_end_ok = false);
1473   void verify_limit();
1474   void verify_step(uint num_edges);
1475   #endif
1476 
1477   // Note:  offset must be signed, since -1 is sometimes passed
1478   DUIterator_Last(const Node* node, ptrdiff_t offset)
1479     : DUIterator_Fast(node, offset) { }
1480 
1481   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1482   void operator<(int)                              {} // do not use
1483 
1484  public:
1485   DUIterator_Last() { }
1486   // initialize to garbage
1487 
1488   DUIterator_Last(const DUIterator_Last& that) = default;
1489 
1490   void operator--()
1491     { _outp--;              VDUI_ONLY(verify_step(1));  }
1492 
1493   void operator-=(uint n)
1494     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1495 
1496   bool operator>=(DUIterator_Last& limit) {
1497     I_VDUI_ONLY(*this, this->verify(_node, true));
1498     I_VDUI_ONLY(limit, limit.verify_limit());
1499     return _outp >= limit._outp;
1500   }
1501 
1502   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1503 };
1504 
1505 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1506   // Assign a limit pointer to the reference argument:
1507   imin = DUIterator_Last(this, 0);
1508   // Return the initial pointer:
1509   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1510 }
1511 Node* Node::last_out(DUIterator_Last& i) const {
1512   I_VDUI_ONLY(i, i.verify(this));
1513   return debug_only(i._last=) *i._outp;
1514 }
1515 
1516 #endif //OPTO_DU_ITERATOR_ASSERT
1517 
1518 #undef I_VDUI_ONLY
1519 #undef VDUI_ONLY
1520 
1521 // An Iterator that truly follows the iterator pattern.  Doesn't
1522 // support deletion but could be made to.
1523 //
1524 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1525 //     Node* m = i.get();
1526 //
1527 class SimpleDUIterator : public StackObj {
1528  private:
1529   Node* node;
1530   DUIterator_Fast i;
1531   DUIterator_Fast imax;
1532  public:
1533   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1534   bool has_next() { return i < imax; }
1535   void next() { i++; }
1536   Node* get() { return node->fast_out(i); }
1537 };
1538 
1539 
1540 //-----------------------------------------------------------------------------
1541 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1542 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1543 // Note that the constructor just zeros things, and since I use Arena
1544 // allocation I do not need a destructor to reclaim storage.
1545 class Node_Array : public ResourceObj {
1546   friend class VMStructs;
1547 protected:
1548   Arena* _a;                    // Arena to allocate in
1549   uint   _max;
1550   Node** _nodes;
1551   void   grow( uint i );        // Grow array node to fit
1552 public:
1553   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1554     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1555     clear();
1556   }
1557 
1558   Node_Array(Node_Array* na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1559   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1560   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1561   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1562   Node** adr() { return _nodes; }
1563   // Extend the mapping: index i maps to Node *n.
1564   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1565   void insert( uint i, Node *n );
1566   void remove( uint i );        // Remove, preserving order
1567   // Clear all entries in _nodes to NULL but keep storage
1568   void clear() {
1569     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1570   }
1571 
1572   uint Size() const { return _max; }
1573   void dump() const;
1574 };
1575 
1576 class Node_List : public Node_Array {
1577   friend class VMStructs;
1578   uint _cnt;
1579 public:
1580   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1581   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1582   bool contains(const Node* n) const {
1583     for (uint e = 0; e < size(); e++) {
1584       if (at(e) == n) return true;
1585     }
1586     return false;
1587   }
1588   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1589   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1590   void push( Node *b ) { map(_cnt++,b); }
1591   void yank( Node *n );         // Find and remove
1592   Node *pop() { return _nodes[--_cnt]; }
1593   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1594   void copy(const Node_List& from) {
1595     if (from._max > _max) {
1596       grow(from._max);
1597     }
1598     _cnt = from._cnt;
1599     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1600   }
1601 
1602   uint size() const { return _cnt; }
1603   void dump() const;
1604   void dump_simple() const;
1605 };
1606 
1607 //------------------------------Unique_Node_List-------------------------------
1608 class Unique_Node_List : public Node_List {
1609   friend class VMStructs;
1610   VectorSet _in_worklist;
1611   uint _clock_index;            // Index in list where to pop from next
1612 public:
1613   Unique_Node_List() : Node_List(), _clock_index(0) {}
1614   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1615 
1616   void remove( Node *n );
1617   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1618   VectorSet& member_set(){ return _in_worklist; }
1619 
1620   void push(Node* b) {
1621     if( !_in_worklist.test_set(b->_idx) )
1622       Node_List::push(b);
1623   }
1624   Node *pop() {
1625     if( _clock_index >= size() ) _clock_index = 0;
1626     Node *b = at(_clock_index);
1627     map( _clock_index, Node_List::pop());
1628     if (size() != 0) _clock_index++; // Always start from 0
1629     _in_worklist.remove(b->_idx);
1630     return b;
1631   }
1632   Node *remove(uint i) {
1633     Node *b = Node_List::at(i);
1634     _in_worklist.remove(b->_idx);
1635     map(i,Node_List::pop());
1636     return b;
1637   }
1638   void yank(Node *n) {
1639     _in_worklist.remove(n->_idx);
1640     Node_List::yank(n);
1641   }
1642   void  clear() {
1643     _in_worklist.clear();        // Discards storage but grows automatically
1644     Node_List::clear();
1645     _clock_index = 0;
1646   }
1647 
1648   // Used after parsing to remove useless nodes before Iterative GVN
1649   void remove_useless_nodes(VectorSet& useful);
1650 
1651   bool contains(const Node* n) const {
1652     fatal("use faster member() instead");
1653     return false;
1654   }
1655 
1656 #ifndef PRODUCT
1657   void print_set() const { _in_worklist.print(); }
1658 #endif
1659 };
1660 
1661 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1662 inline void Compile::record_for_igvn(Node* n) {
1663   _for_igvn->push(n);
1664 }
1665 
1666 //------------------------------Node_Stack-------------------------------------
1667 class Node_Stack {
1668   friend class VMStructs;
1669 protected:
1670   struct INode {
1671     Node *node; // Processed node
1672     uint  indx; // Index of next node's child
1673   };
1674   INode *_inode_top; // tos, stack grows up
1675   INode *_inode_max; // End of _inodes == _inodes + _max
1676   INode *_inodes;    // Array storage for the stack
1677   Arena *_a;         // Arena to allocate in
1678   void grow();
1679 public:
1680   Node_Stack(int size) {
1681     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1682     _a = Thread::current()->resource_area();
1683     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1684     _inode_max = _inodes + max;
1685     _inode_top = _inodes - 1; // stack is empty
1686   }
1687 
1688   Node_Stack(Arena *a, int size) : _a(a) {
1689     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1690     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1691     _inode_max = _inodes + max;
1692     _inode_top = _inodes - 1; // stack is empty
1693   }
1694 
1695   void pop() {
1696     assert(_inode_top >= _inodes, "node stack underflow");
1697     --_inode_top;
1698   }
1699   void push(Node *n, uint i) {
1700     ++_inode_top;
1701     if (_inode_top >= _inode_max) grow();
1702     INode *top = _inode_top; // optimization
1703     top->node = n;
1704     top->indx = i;
1705   }
1706   Node *node() const {
1707     return _inode_top->node;
1708   }
1709   Node* node_at(uint i) const {
1710     assert(_inodes + i <= _inode_top, "in range");
1711     return _inodes[i].node;
1712   }
1713   uint index() const {
1714     return _inode_top->indx;
1715   }
1716   uint index_at(uint i) const {
1717     assert(_inodes + i <= _inode_top, "in range");
1718     return _inodes[i].indx;
1719   }
1720   void set_node(Node *n) {
1721     _inode_top->node = n;
1722   }
1723   void set_index(uint i) {
1724     _inode_top->indx = i;
1725   }
1726   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1727   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1728   bool is_nonempty() const { return (_inode_top >= _inodes); }
1729   bool is_empty() const { return (_inode_top < _inodes); }
1730   void clear() { _inode_top = _inodes - 1; } // retain storage
1731 
1732   // Node_Stack is used to map nodes.
1733   Node* find(uint idx) const;
1734 };
1735 
1736 
1737 //-----------------------------Node_Notes--------------------------------------
1738 // Debugging or profiling annotations loosely and sparsely associated
1739 // with some nodes.  See Compile::node_notes_at for the accessor.
1740 class Node_Notes {
1741   friend class VMStructs;
1742   JVMState* _jvms;
1743 
1744 public:
1745   Node_Notes(JVMState* jvms = NULL) {
1746     _jvms = jvms;
1747   }
1748 
1749   JVMState* jvms()            { return _jvms; }
1750   void  set_jvms(JVMState* x) {        _jvms = x; }
1751 
1752   // True if there is nothing here.
1753   bool is_clear() {
1754     return (_jvms == NULL);
1755   }
1756 
1757   // Make there be nothing here.
1758   void clear() {
1759     _jvms = NULL;
1760   }
1761 
1762   // Make a new, clean node notes.
1763   static Node_Notes* make(Compile* C) {
1764     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1765     nn->clear();
1766     return nn;
1767   }
1768 
1769   Node_Notes* clone(Compile* C) {
1770     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1771     (*nn) = (*this);
1772     return nn;
1773   }
1774 
1775   // Absorb any information from source.
1776   bool update_from(Node_Notes* source) {
1777     bool changed = false;
1778     if (source != NULL) {
1779       if (source->jvms() != NULL) {
1780         set_jvms(source->jvms());
1781         changed = true;
1782       }
1783     }
1784     return changed;
1785   }
1786 };
1787 
1788 // Inlined accessors for Compile::node_nodes that require the preceding class:
1789 inline Node_Notes*
1790 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1791                            int idx, bool can_grow) {
1792   assert(idx >= 0, "oob");
1793   int block_idx = (idx >> _log2_node_notes_block_size);
1794   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1795   if (grow_by >= 0) {
1796     if (!can_grow) return NULL;
1797     grow_node_notes(arr, grow_by + 1);
1798   }
1799   if (arr == NULL) return NULL;
1800   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1801   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1802 }
1803 
1804 inline bool
1805 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1806   if (value == NULL || value->is_clear())
1807     return false;  // nothing to write => write nothing
1808   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1809   assert(loc != NULL, "");
1810   return loc->update_from(value);
1811 }
1812 
1813 
1814 //------------------------------TypeNode---------------------------------------
1815 // Node with a Type constant.
1816 class TypeNode : public Node {
1817 protected:
1818   virtual uint hash() const;    // Check the type
1819   virtual bool cmp( const Node &n ) const;
1820   virtual uint size_of() const; // Size is bigger
1821   const Type* const _type;
1822 public:
1823   void set_type(const Type* t) {
1824     assert(t != NULL, "sanity");
1825     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1826     *(const Type**)&_type = t;   // cast away const-ness
1827     // If this node is in the hash table, make sure it doesn't need a rehash.
1828     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1829   }
1830   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1831   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1832     init_class_id(Class_Type);
1833   }
1834   virtual const Type* Value(PhaseGVN* phase) const;
1835   virtual const Type *bottom_type() const;
1836   virtual       uint  ideal_reg() const;
1837 #ifndef PRODUCT
1838   virtual void dump_spec(outputStream *st) const;
1839   virtual void dump_compact_spec(outputStream *st) const;
1840 #endif
1841 };
1842 
1843 #endif // SHARE_OPTO_NODE_HPP