1 /*
   2  * Copyright (c) 1997, 2022, 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 LShiftNode;
 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 MachReturnNode;
 119 class MachSafePointNode;
 120 class MachSpillCopyNode;
 121 class MachTempNode;
 122 class MachMergeNode;
 123 class MachMemBarNode;
 124 class Matcher;
 125 class MemBarNode;
 126 class MemBarStoreStoreNode;
 127 class MemNode;
 128 class MergeMemNode;
 129 class MoveNode;
 130 class MulNode;
 131 class MultiNode;
 132 class MultiBranchNode;
 133 class NeverBranchNode;
 134 class Opaque1Node;
 135 class OuterStripMinedLoopNode;
 136 class OuterStripMinedLoopEndNode;
 137 class Node;
 138 class Node_Array;
 139 class Node_List;
 140 class Node_Stack;
 141 class OopMap;
 142 class ParmNode;
 143 class PCTableNode;
 144 class PhaseCCP;
 145 class PhaseGVN;
 146 class PhaseIterGVN;
 147 class PhaseRegAlloc;
 148 class PhaseTransform;
 149 class PhaseValues;
 150 class PhiNode;
 151 class Pipeline;
 152 class ProjNode;
 153 class RangeCheckNode;
 154 class RegMask;
 155 class RegionNode;
 156 class RootNode;
 157 class SafePointNode;
 158 class SafePointScalarObjectNode;
 159 class StartNode;
 160 class State;
 161 class StoreNode;
 162 class SubNode;
 163 class SubTypeCheckNode;
 164 class Type;
 165 class TypeNode;
 166 class UnlockNode;
 167 class VectorNode;
 168 class LoadVectorNode;
 169 class LoadVectorMaskedNode;
 170 class StoreVectorMaskedNode;
 171 class LoadVectorGatherNode;
 172 class StoreVectorNode;
 173 class StoreVectorScatterNode;
 174 class VectorMaskCmpNode;
 175 class VectorUnboxNode;
 176 class VectorSet;
 177 class VectorReinterpretNode;
 178 class ShiftVNode;
 179 class ExpandVNode;
 180 class CompressVNode;
 181 class CompressMNode;
 182 
 183 
 184 #ifndef OPTO_DU_ITERATOR_ASSERT
 185 #ifdef ASSERT
 186 #define OPTO_DU_ITERATOR_ASSERT 1
 187 #else
 188 #define OPTO_DU_ITERATOR_ASSERT 0
 189 #endif
 190 #endif //OPTO_DU_ITERATOR_ASSERT
 191 
 192 #if OPTO_DU_ITERATOR_ASSERT
 193 class DUIterator;
 194 class DUIterator_Fast;
 195 class DUIterator_Last;
 196 #else
 197 typedef uint   DUIterator;
 198 typedef Node** DUIterator_Fast;
 199 typedef Node** DUIterator_Last;
 200 #endif
 201 
 202 // Node Sentinel
 203 #define NodeSentinel (Node*)-1
 204 
 205 // Unknown count frequency
 206 #define COUNT_UNKNOWN (-1.0f)
 207 
 208 //------------------------------Node-------------------------------------------
 209 // Nodes define actions in the program.  They create values, which have types.
 210 // They are both vertices in a directed graph and program primitives.  Nodes
 211 // are labeled; the label is the "opcode", the primitive function in the lambda
 212 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 213 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 214 // the Node's function.  These inputs also define a Type equation for the Node.
 215 // Solving these Type equations amounts to doing dataflow analysis.
 216 // Control and data are uniformly represented in the graph.  Finally, Nodes
 217 // have a unique dense integer index which is used to index into side arrays
 218 // whenever I have phase-specific information.
 219 
 220 class Node {
 221   friend class VMStructs;
 222 
 223   // Lots of restrictions on cloning Nodes
 224   NONCOPYABLE(Node);
 225 
 226 public:
 227   friend class Compile;
 228   #if OPTO_DU_ITERATOR_ASSERT
 229   friend class DUIterator_Common;
 230   friend class DUIterator;
 231   friend class DUIterator_Fast;
 232   friend class DUIterator_Last;
 233   #endif
 234 
 235   // Because Nodes come and go, I define an Arena of Node structures to pull
 236   // from.  This should allow fast access to node creation & deletion.  This
 237   // field is a local cache of a value defined in some "program fragment" for
 238   // which these Nodes are just a part of.
 239 
 240   inline void* operator new(size_t x) throw() {
 241     Compile* C = Compile::current();
 242     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 243     return (void*)n;
 244   }
 245 
 246   // Delete is a NOP
 247   void operator delete( void *ptr ) {}
 248   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 249   void destruct(PhaseValues* phase);
 250 
 251   // Create a new Node.  Required is the number is of inputs required for
 252   // semantic correctness.
 253   Node( uint required );
 254 
 255   // Create a new Node with given input edges.
 256   // This version requires use of the "edge-count" new.
 257   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 258   Node( Node *n0 );
 259   Node( Node *n0, Node *n1 );
 260   Node( Node *n0, Node *n1, Node *n2 );
 261   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 262   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 263   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 264   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 265             Node *n4, Node *n5, Node *n6 );
 266 
 267   // Clone an inherited Node given only the base Node type.
 268   Node* clone() const;
 269 
 270   // Clone a Node, immediately supplying one or two new edges.
 271   // The first and second arguments, if non-null, replace in(1) and in(2),
 272   // respectively.
 273   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 274     Node* nn = clone();
 275     if (in1 != NULL)  nn->set_req(1, in1);
 276     if (in2 != NULL)  nn->set_req(2, in2);
 277     return nn;
 278   }
 279 
 280 private:
 281   // Shared setup for the above constructors.
 282   // Handles all interactions with Compile::current.
 283   // Puts initial values in all Node fields except _idx.
 284   // Returns the initial value for _idx, which cannot
 285   // be initialized by assignment.
 286   inline int Init(int req);
 287 
 288 //----------------- input edge handling
 289 protected:
 290   friend class PhaseCFG;        // Access to address of _in array elements
 291   Node **_in;                   // Array of use-def references to Nodes
 292   Node **_out;                  // Array of def-use references to Nodes
 293 
 294   // Input edges are split into two categories.  Required edges are required
 295   // for semantic correctness; order is important and NULLs are allowed.
 296   // Precedence edges are used to help determine execution order and are
 297   // added, e.g., for scheduling purposes.  They are unordered and not
 298   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 299   // are required, from _cnt to _max-1 are precedence edges.
 300   node_idx_t _cnt;              // Total number of required Node inputs.
 301 
 302   node_idx_t _max;              // Actual length of input array.
 303 
 304   // Output edges are an unordered list of def-use edges which exactly
 305   // correspond to required input edges which point from other nodes
 306   // to this one.  Thus the count of the output edges is the number of
 307   // users of this node.
 308   node_idx_t _outcnt;           // Total number of Node outputs.
 309 
 310   node_idx_t _outmax;           // Actual length of output array.
 311 
 312   // Grow the actual input array to the next larger power-of-2 bigger than len.
 313   void grow( uint len );
 314   // Grow the output array to the next larger power-of-2 bigger than len.
 315   void out_grow( uint len );
 316 
 317  public:
 318   // Each Node is assigned a unique small/dense number.  This number is used
 319   // to index into auxiliary arrays of data and bit vectors.
 320   // The field _idx is declared constant to defend against inadvertent assignments,
 321   // since it is used by clients as a naked field. However, the field's value can be
 322   // changed using the set_idx() method.
 323   //
 324   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 325   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 326   // preserved in _parse_idx.
 327   const node_idx_t _idx;
 328   DEBUG_ONLY(const node_idx_t _parse_idx;)
 329   // IGV node identifier. Two nodes, possibly in different compilation phases,
 330   // have the same IGV identifier if (and only if) they are the very same node
 331   // (same memory address) or one is "derived" from the other (by e.g.
 332   // renumbering or matching). This identifier makes it possible to follow the
 333   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 334   NOT_PRODUCT(node_idx_t _igv_idx;)
 335 
 336   // Get the (read-only) number of input edges
 337   uint req() const { return _cnt; }
 338   uint len() const { return _max; }
 339   // Get the (read-only) number of output edges
 340   uint outcnt() const { return _outcnt; }
 341 
 342 #if OPTO_DU_ITERATOR_ASSERT
 343   // Iterate over the out-edges of this node.  Deletions are illegal.
 344   inline DUIterator outs() const;
 345   // Use this when the out array might have changed to suppress asserts.
 346   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 347   // Does the node have an out at this position?  (Used for iteration.)
 348   inline bool has_out(DUIterator& i) const;
 349   inline Node*    out(DUIterator& i) const;
 350   // Iterate over the out-edges of this node.  All changes are illegal.
 351   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 352   inline Node*    fast_out(DUIterator_Fast& i) const;
 353   // Iterate over the out-edges of this node, deleting one at a time.
 354   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 355   inline Node*    last_out(DUIterator_Last& i) const;
 356   // The inline bodies of all these methods are after the iterator definitions.
 357 #else
 358   // Iterate over the out-edges of this node.  Deletions are illegal.
 359   // This iteration uses integral indexes, to decouple from array reallocations.
 360   DUIterator outs() const  { return 0; }
 361   // Use this when the out array might have changed to suppress asserts.
 362   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 363 
 364   // Reference to the i'th output Node.  Error if out of bounds.
 365   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 366   // Does the node have an out at this position?  (Used for iteration.)
 367   bool has_out(DUIterator i) const { return i < _outcnt; }
 368 
 369   // Iterate over the out-edges of this node.  All changes are illegal.
 370   // This iteration uses a pointer internal to the out array.
 371   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 372     Node** out = _out;
 373     // Assign a limit pointer to the reference argument:
 374     max = out + (ptrdiff_t)_outcnt;
 375     // Return the base pointer:
 376     return out;
 377   }
 378   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 379   // Iterate over the out-edges of this node, deleting one at a time.
 380   // This iteration uses a pointer internal to the out array.
 381   DUIterator_Last last_outs(DUIterator_Last& min) const {
 382     Node** out = _out;
 383     // Assign a limit pointer to the reference argument:
 384     min = out;
 385     // Return the pointer to the start of the iteration:
 386     return out + (ptrdiff_t)_outcnt - 1;
 387   }
 388   Node*    last_out(DUIterator_Last i) const  { return *i; }
 389 #endif
 390 
 391   // Reference to the i'th input Node.  Error if out of bounds.
 392   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 393   // Reference to the i'th input Node.  NULL if out of bounds.
 394   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 395   // Reference to the i'th output Node.  Error if out of bounds.
 396   // Use this accessor sparingly.  We are going trying to use iterators instead.
 397   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 398   // Return the unique out edge.
 399   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 400   // Delete out edge at position 'i' by moving last out edge to position 'i'
 401   void  raw_del_out(uint i) {
 402     assert(i < _outcnt,"oob");
 403     assert(_outcnt > 0,"oob");
 404     #if OPTO_DU_ITERATOR_ASSERT
 405     // Record that a change happened here.
 406     debug_only(_last_del = _out[i]; ++_del_tick);
 407     #endif
 408     _out[i] = _out[--_outcnt];
 409     // Smash the old edge so it can't be used accidentally.
 410     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 411   }
 412 
 413 #ifdef ASSERT
 414   bool is_dead() const;
 415 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 416   bool is_reachable_from_root() const;
 417 #endif
 418   // Check whether node has become unreachable
 419   bool is_unreachable(PhaseIterGVN &igvn) const;
 420 
 421   // Set a required input edge, also updates corresponding output edge
 422   void add_req( Node *n ); // Append a NEW required input
 423   void add_req( Node *n0, Node *n1 ) {
 424     add_req(n0); add_req(n1); }
 425   void add_req( Node *n0, Node *n1, Node *n2 ) {
 426     add_req(n0); add_req(n1); add_req(n2); }
 427   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 428   void del_req( uint idx ); // Delete required edge & compact
 429   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 430   void ins_req( uint i, Node *n ); // Insert a NEW required input
 431   void set_req( uint i, Node *n ) {
 432     assert( is_not_dead(n), "can not use dead node");
 433     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 434     assert( !VerifyHashTableKeys || _hash_lock == 0,
 435             "remove node from hash table before modifying it");
 436     Node** p = &_in[i];    // cache this._in, across the del_out call
 437     if (*p != NULL)  (*p)->del_out((Node *)this);
 438     (*p) = n;
 439     if (n != NULL)      n->add_out((Node *)this);
 440     Compile::current()->record_modified_node(this);
 441   }
 442   // Light version of set_req() to init inputs after node creation.
 443   void init_req( uint i, Node *n ) {
 444     assert( i == 0 && this == n ||
 445             is_not_dead(n), "can not use dead node");
 446     assert( i < _cnt, "oob");
 447     assert( !VerifyHashTableKeys || _hash_lock == 0,
 448             "remove node from hash table before modifying it");
 449     assert( _in[i] == NULL, "sanity");
 450     _in[i] = n;
 451     if (n != NULL)      n->add_out((Node *)this);
 452     Compile::current()->record_modified_node(this);
 453   }
 454   // Find first occurrence of n among my edges:
 455   int find_edge(Node* n);
 456   int find_prec_edge(Node* n) {
 457     for (uint i = req(); i < len(); i++) {
 458       if (_in[i] == n) return i;
 459       if (_in[i] == NULL) {
 460         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 461         break;
 462       }
 463     }
 464     return -1;
 465   }
 466   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = NULL);
 467   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 468   // NULL out all inputs to eliminate incoming Def-Use edges.
 469   void disconnect_inputs(Compile* C);
 470 
 471   // Quickly, return true if and only if I am Compile::current()->top().
 472   bool is_top() const {
 473     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 474     return (_out == NULL);
 475   }
 476   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 477   void setup_is_top();
 478 
 479   // Strip away casting.  (It is depth-limited.)
 480   Node* uncast(bool keep_deps = false) const;
 481   // Return whether two Nodes are equivalent, after stripping casting.
 482   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 483     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 484   }
 485 
 486   // Find out of current node that matches opcode.
 487   Node* find_out_with(int opcode);
 488   // Return true if the current node has an out that matches opcode.
 489   bool has_out_with(int opcode);
 490   // Return true if the current node has an out that matches any of the opcodes.
 491   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 492 
 493 private:
 494   static Node* uncast_helper(const Node* n, bool keep_deps);
 495 
 496   // Add an output edge to the end of the list
 497   void add_out( Node *n ) {
 498     if (is_top())  return;
 499     if( _outcnt == _outmax ) out_grow(_outcnt);
 500     _out[_outcnt++] = n;
 501   }
 502   // Delete an output edge
 503   void del_out( Node *n ) {
 504     if (is_top())  return;
 505     Node** outp = &_out[_outcnt];
 506     // Find and remove n
 507     do {
 508       assert(outp > _out, "Missing Def-Use edge");
 509     } while (*--outp != n);
 510     *outp = _out[--_outcnt];
 511     // Smash the old edge so it can't be used accidentally.
 512     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 513     // Record that a change happened here.
 514     #if OPTO_DU_ITERATOR_ASSERT
 515     debug_only(_last_del = n; ++_del_tick);
 516     #endif
 517   }
 518   // Close gap after removing edge.
 519   void close_prec_gap_at(uint gap) {
 520     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 521     uint i = gap;
 522     Node *last = NULL;
 523     for (; i < _max-1; ++i) {
 524       Node *next = _in[i+1];
 525       if (next == NULL) break;
 526       last = next;
 527     }
 528     _in[gap] = last; // Move last slot to empty one.
 529     _in[i] = NULL;   // NULL out last slot.
 530   }
 531 
 532 public:
 533   // Globally replace this node by a given new node, updating all uses.
 534   void replace_by(Node* new_node);
 535   // Globally replace this node by a given new node, updating all uses
 536   // and cutting input edges of old node.
 537   void subsume_by(Node* new_node, Compile* c) {
 538     replace_by(new_node);
 539     disconnect_inputs(c);
 540   }
 541   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 542   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 543   // Find the one non-null required input.  RegionNode only
 544   Node *nonnull_req() const;
 545   // Add or remove precedence edges
 546   void add_prec( Node *n );
 547   void rm_prec( uint i );
 548 
 549   // Note: prec(i) will not necessarily point to n if edge already exists.
 550   void set_prec( uint i, Node *n ) {
 551     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 552     assert(is_not_dead(n), "can not use dead node");
 553     assert(i >= _cnt, "not a precedence edge");
 554     // Avoid spec violation: duplicated prec edge.
 555     if (_in[i] == n) return;
 556     if (n == NULL || find_prec_edge(n) != -1) {
 557       rm_prec(i);
 558       return;
 559     }
 560     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 561     _in[i] = n;
 562     n->add_out((Node *)this);
 563   }
 564 
 565   // Set this node's index, used by cisc_version to replace current node
 566   void set_idx(uint new_idx) {
 567     const node_idx_t* ref = &_idx;
 568     *(node_idx_t*)ref = new_idx;
 569   }
 570   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 571   void swap_edges(uint i1, uint i2) {
 572     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 573     // Def-Use info is unchanged
 574     Node* n1 = in(i1);
 575     Node* n2 = in(i2);
 576     _in[i1] = n2;
 577     _in[i2] = n1;
 578     // If this node is in the hash table, make sure it doesn't need a rehash.
 579     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 580   }
 581 
 582   // Iterators over input Nodes for a Node X are written as:
 583   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 584   // NOTE: Required edges can contain embedded NULL pointers.
 585 
 586 //----------------- Other Node Properties
 587 
 588   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 589   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 590   //
 591   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 592   // the type of the node the ID represents; another subset of an ID's bits are reserved
 593   // for the superclasses of the node represented by the ID.
 594   //
 595   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 596   // returns false. A.is_A() returns true.
 597   //
 598   // If two classes, A and B, have the same superclass, a different bit of A's class id
 599   // is reserved for A's type than for B's type. That bit is specified by the third
 600   // parameter in the macro DEFINE_CLASS_ID.
 601   //
 602   // By convention, classes with deeper hierarchy are declared first. Moreover,
 603   // classes with the same hierarchy depth are sorted by usage frequency.
 604   //
 605   // The query method masks the bits to cut off bits of subclasses and then compares
 606   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 607   //
 608   //  Class_MachCall=30, ClassMask_MachCall=31
 609   // 12               8               4               0
 610   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 611   //                                  |   |   |   |
 612   //                                  |   |   |   Bit_Mach=2
 613   //                                  |   |   Bit_MachReturn=4
 614   //                                  |   Bit_MachSafePoint=8
 615   //                                  Bit_MachCall=16
 616   //
 617   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 618   // 12               8               4               0
 619   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 620   //                              |   |   |
 621   //                              |   |   Bit_Region=8
 622   //                              |   Bit_Loop=16
 623   //                              Bit_CountedLoop=32
 624 
 625   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 626   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 627   Class_##cl = Class_##supcl + Bit_##cl , \
 628   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 629 
 630   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 631   // so that its values fit into 32 bits.
 632   enum NodeClasses {
 633     Bit_Node   = 0x00000000,
 634     Class_Node = 0x00000000,
 635     ClassMask_Node = 0xFFFFFFFF,
 636 
 637     DEFINE_CLASS_ID(Multi, Node, 0)
 638       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 639         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 640           DEFINE_CLASS_ID(CallJava,         Call, 0)
 641             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 642             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 643           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 644             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 645               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 646           DEFINE_CLASS_ID(Allocate,         Call, 2)
 647             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 648           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 649             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 650             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 651           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 652           DEFINE_CLASS_ID(CallNative,       Call, 5)
 653       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 654         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 655           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 656           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 657         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 658           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 659             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 660             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 661           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 662           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 663         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 664       DEFINE_CLASS_ID(Start,       Multi, 2)
 665       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 666         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 667         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 668 
 669     DEFINE_CLASS_ID(Mach,  Node, 1)
 670       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 671         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 672           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 673             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 674               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 675               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 676             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 677               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 678             DEFINE_CLASS_ID(MachCallNative,       MachCall, 2)
 679       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 680         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 681         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 682         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 683       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 684       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 685       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 686       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 687         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 688       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 689       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 690 
 691     DEFINE_CLASS_ID(Type,  Node, 2)
 692       DEFINE_CLASS_ID(Phi,   Type, 0)
 693       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 694         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 695         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 696         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 697         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 698         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 699         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 700       DEFINE_CLASS_ID(CMove, Type, 3)
 701       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 702       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 703         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 704         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 705       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 706         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 707         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 708       DEFINE_CLASS_ID(Vector, Type, 7)
 709         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 710         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 711         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 712         DEFINE_CLASS_ID(ShiftV, Vector, 3)
 713         DEFINE_CLASS_ID(CompressV, Vector, 4)
 714         DEFINE_CLASS_ID(ExpandV, Vector, 5)
 715         DEFINE_CLASS_ID(CompressM, Vector, 6)
 716 
 717     DEFINE_CLASS_ID(Proj,  Node, 3)
 718       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 719       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 720       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 721         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 722         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 723       DEFINE_CLASS_ID(Parm,      Proj, 4)
 724       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 725 
 726     DEFINE_CLASS_ID(Mem, Node, 4)
 727       DEFINE_CLASS_ID(Load, Mem, 0)
 728         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 729           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 730           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 1)
 731       DEFINE_CLASS_ID(Store, Mem, 1)
 732         DEFINE_CLASS_ID(StoreVector, Store, 0)
 733           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 734           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 1)
 735       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 736         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 737           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 738         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 739 
 740     DEFINE_CLASS_ID(Region, Node, 5)
 741       DEFINE_CLASS_ID(Loop, Region, 0)
 742         DEFINE_CLASS_ID(Root,                Loop, 0)
 743         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 744           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 745           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 746         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 747 
 748     DEFINE_CLASS_ID(Sub,   Node, 6)
 749       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 750         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 751         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 752         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 753 
 754     DEFINE_CLASS_ID(MergeMem, Node, 7)
 755     DEFINE_CLASS_ID(Bool,     Node, 8)
 756     DEFINE_CLASS_ID(AddP,     Node, 9)
 757     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 758     DEFINE_CLASS_ID(Add,      Node, 11)
 759     DEFINE_CLASS_ID(Mul,      Node, 12)
 760     DEFINE_CLASS_ID(ClearArray, Node, 14)
 761     DEFINE_CLASS_ID(Halt,     Node, 15)
 762     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 763     DEFINE_CLASS_ID(Move,     Node, 17)
 764     DEFINE_CLASS_ID(LShift,   Node, 18)
 765 
 766     _max_classes  = ClassMask_Move
 767   };
 768   #undef DEFINE_CLASS_ID
 769 
 770   // Flags are sorted by usage frequency.
 771   enum NodeFlags {
 772     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 773     Flag_rematerialize               = 1 << 1,
 774     Flag_needs_anti_dependence_check = 1 << 2,
 775     Flag_is_macro                    = 1 << 3,
 776     Flag_is_Con                      = 1 << 4,
 777     Flag_is_cisc_alternate           = 1 << 5,
 778     Flag_is_dead_loop_safe           = 1 << 6,
 779     Flag_may_be_short_branch         = 1 << 7,
 780     Flag_avoid_back_to_back_before   = 1 << 8,
 781     Flag_avoid_back_to_back_after    = 1 << 9,
 782     Flag_has_call                    = 1 << 10,
 783     Flag_is_reduction                = 1 << 11,
 784     Flag_is_scheduled                = 1 << 12,
 785     Flag_has_vector_mask_set         = 1 << 13,
 786     Flag_is_expensive                = 1 << 14,
 787     Flag_is_predicated_vector        = 1 << 15,
 788     Flag_for_post_loop_opts_igvn     = 1 << 16,
 789     Flag_is_removed_by_peephole      = 1 << 17,
 790     Flag_is_predicated_using_blend   = 1 << 18,
 791     _last_flag                       = Flag_is_predicated_using_blend
 792   };
 793 
 794   class PD;
 795 
 796 private:
 797   juint _class_id;
 798   juint _flags;
 799 
 800   static juint max_flags();
 801 
 802 protected:
 803   // These methods should be called from constructors only.
 804   void init_class_id(juint c) {
 805     _class_id = c; // cast out const
 806   }
 807   void init_flags(uint fl) {
 808     assert(fl <= max_flags(), "invalid node flag");
 809     _flags |= fl;
 810   }
 811   void clear_flag(uint fl) {
 812     assert(fl <= max_flags(), "invalid node flag");
 813     _flags &= ~fl;
 814   }
 815 
 816 public:
 817   const juint class_id() const { return _class_id; }
 818 
 819   const juint flags() const { return _flags; }
 820 
 821   void add_flag(juint fl) { init_flags(fl); }
 822 
 823   void remove_flag(juint fl) { clear_flag(fl); }
 824 
 825   // Return a dense integer opcode number
 826   virtual int Opcode() const;
 827 
 828   // Virtual inherited Node size
 829   virtual uint size_of() const;
 830 
 831   // Other interesting Node properties
 832   #define DEFINE_CLASS_QUERY(type)                           \
 833   bool is_##type() const {                                   \
 834     return ((_class_id & ClassMask_##type) == Class_##type); \
 835   }                                                          \
 836   type##Node *as_##type() const {                            \
 837     assert(is_##type(), "invalid node class: %s", Name()); \
 838     return (type##Node*)this;                                \
 839   }                                                          \
 840   type##Node* isa_##type() const {                           \
 841     return (is_##type()) ? as_##type() : NULL;               \
 842   }
 843 
 844   DEFINE_CLASS_QUERY(AbstractLock)
 845   DEFINE_CLASS_QUERY(Add)
 846   DEFINE_CLASS_QUERY(AddP)
 847   DEFINE_CLASS_QUERY(Allocate)
 848   DEFINE_CLASS_QUERY(AllocateArray)
 849   DEFINE_CLASS_QUERY(ArrayCopy)
 850   DEFINE_CLASS_QUERY(BaseCountedLoop)
 851   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 852   DEFINE_CLASS_QUERY(Bool)
 853   DEFINE_CLASS_QUERY(BoxLock)
 854   DEFINE_CLASS_QUERY(Call)
 855   DEFINE_CLASS_QUERY(CallNative)
 856   DEFINE_CLASS_QUERY(CallDynamicJava)
 857   DEFINE_CLASS_QUERY(CallJava)
 858   DEFINE_CLASS_QUERY(CallLeaf)
 859   DEFINE_CLASS_QUERY(CallLeafNoFP)
 860   DEFINE_CLASS_QUERY(CallRuntime)
 861   DEFINE_CLASS_QUERY(CallStaticJava)
 862   DEFINE_CLASS_QUERY(Catch)
 863   DEFINE_CLASS_QUERY(CatchProj)
 864   DEFINE_CLASS_QUERY(CheckCastPP)
 865   DEFINE_CLASS_QUERY(CastII)
 866   DEFINE_CLASS_QUERY(CastLL)
 867   DEFINE_CLASS_QUERY(ConstraintCast)
 868   DEFINE_CLASS_QUERY(ClearArray)
 869   DEFINE_CLASS_QUERY(CMove)
 870   DEFINE_CLASS_QUERY(Cmp)
 871   DEFINE_CLASS_QUERY(CountedLoop)
 872   DEFINE_CLASS_QUERY(CountedLoopEnd)
 873   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 874   DEFINE_CLASS_QUERY(DecodeN)
 875   DEFINE_CLASS_QUERY(DecodeNKlass)
 876   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 877   DEFINE_CLASS_QUERY(EncodeP)
 878   DEFINE_CLASS_QUERY(EncodePKlass)
 879   DEFINE_CLASS_QUERY(FastLock)
 880   DEFINE_CLASS_QUERY(FastUnlock)
 881   DEFINE_CLASS_QUERY(Halt)
 882   DEFINE_CLASS_QUERY(If)
 883   DEFINE_CLASS_QUERY(RangeCheck)
 884   DEFINE_CLASS_QUERY(IfProj)
 885   DEFINE_CLASS_QUERY(IfFalse)
 886   DEFINE_CLASS_QUERY(IfTrue)
 887   DEFINE_CLASS_QUERY(Initialize)
 888   DEFINE_CLASS_QUERY(Jump)
 889   DEFINE_CLASS_QUERY(JumpProj)
 890   DEFINE_CLASS_QUERY(LongCountedLoop)
 891   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 892   DEFINE_CLASS_QUERY(Load)
 893   DEFINE_CLASS_QUERY(LoadStore)
 894   DEFINE_CLASS_QUERY(LoadStoreConditional)
 895   DEFINE_CLASS_QUERY(Lock)
 896   DEFINE_CLASS_QUERY(Loop)
 897   DEFINE_CLASS_QUERY(LShift)
 898   DEFINE_CLASS_QUERY(Mach)
 899   DEFINE_CLASS_QUERY(MachBranch)
 900   DEFINE_CLASS_QUERY(MachCall)
 901   DEFINE_CLASS_QUERY(MachCallNative)
 902   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 903   DEFINE_CLASS_QUERY(MachCallJava)
 904   DEFINE_CLASS_QUERY(MachCallLeaf)
 905   DEFINE_CLASS_QUERY(MachCallRuntime)
 906   DEFINE_CLASS_QUERY(MachCallStaticJava)
 907   DEFINE_CLASS_QUERY(MachConstantBase)
 908   DEFINE_CLASS_QUERY(MachConstant)
 909   DEFINE_CLASS_QUERY(MachGoto)
 910   DEFINE_CLASS_QUERY(MachIf)
 911   DEFINE_CLASS_QUERY(MachJump)
 912   DEFINE_CLASS_QUERY(MachNullCheck)
 913   DEFINE_CLASS_QUERY(MachProj)
 914   DEFINE_CLASS_QUERY(MachReturn)
 915   DEFINE_CLASS_QUERY(MachSafePoint)
 916   DEFINE_CLASS_QUERY(MachSpillCopy)
 917   DEFINE_CLASS_QUERY(MachTemp)
 918   DEFINE_CLASS_QUERY(MachMemBar)
 919   DEFINE_CLASS_QUERY(MachMerge)
 920   DEFINE_CLASS_QUERY(Mem)
 921   DEFINE_CLASS_QUERY(MemBar)
 922   DEFINE_CLASS_QUERY(MemBarStoreStore)
 923   DEFINE_CLASS_QUERY(MergeMem)
 924   DEFINE_CLASS_QUERY(Move)
 925   DEFINE_CLASS_QUERY(Mul)
 926   DEFINE_CLASS_QUERY(Multi)
 927   DEFINE_CLASS_QUERY(MultiBranch)
 928   DEFINE_CLASS_QUERY(Opaque1)
 929   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 930   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 931   DEFINE_CLASS_QUERY(Parm)
 932   DEFINE_CLASS_QUERY(PCTable)
 933   DEFINE_CLASS_QUERY(Phi)
 934   DEFINE_CLASS_QUERY(Proj)
 935   DEFINE_CLASS_QUERY(Region)
 936   DEFINE_CLASS_QUERY(Root)
 937   DEFINE_CLASS_QUERY(SafePoint)
 938   DEFINE_CLASS_QUERY(SafePointScalarObject)
 939   DEFINE_CLASS_QUERY(Start)
 940   DEFINE_CLASS_QUERY(Store)
 941   DEFINE_CLASS_QUERY(Sub)
 942   DEFINE_CLASS_QUERY(SubTypeCheck)
 943   DEFINE_CLASS_QUERY(Type)
 944   DEFINE_CLASS_QUERY(Vector)
 945   DEFINE_CLASS_QUERY(VectorMaskCmp)
 946   DEFINE_CLASS_QUERY(VectorUnbox)
 947   DEFINE_CLASS_QUERY(VectorReinterpret)
 948   DEFINE_CLASS_QUERY(CompressV)
 949   DEFINE_CLASS_QUERY(ExpandV)
 950   DEFINE_CLASS_QUERY(CompressM)
 951   DEFINE_CLASS_QUERY(LoadVector)
 952   DEFINE_CLASS_QUERY(LoadVectorGather)
 953   DEFINE_CLASS_QUERY(StoreVector)
 954   DEFINE_CLASS_QUERY(StoreVectorScatter)
 955   DEFINE_CLASS_QUERY(ShiftV)
 956   DEFINE_CLASS_QUERY(Unlock)
 957 
 958   #undef DEFINE_CLASS_QUERY
 959 
 960   // duplicate of is_MachSpillCopy()
 961   bool is_SpillCopy () const {
 962     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 963   }
 964 
 965   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 966   // The data node which is safe to leave in dead loop during IGVN optimization.
 967   bool is_dead_loop_safe() const;
 968 
 969   // is_Copy() returns copied edge index (0 or 1)
 970   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 971 
 972   virtual bool is_CFG() const { return false; }
 973 
 974   // If this node is control-dependent on a test, can it be
 975   // rerouted to a dominating equivalent test?  This is usually
 976   // true of non-CFG nodes, but can be false for operations which
 977   // depend for their correct sequencing on more than one test.
 978   // (In that case, hoisting to a dominating test may silently
 979   // skip some other important test.)
 980   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 981 
 982   // When building basic blocks, I need to have a notion of block beginning
 983   // Nodes, next block selector Nodes (block enders), and next block
 984   // projections.  These calls need to work on their machine equivalents.  The
 985   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 986   bool is_block_start() const {
 987     if ( is_Region() )
 988       return this == (const Node*)in(0);
 989     else
 990       return is_Start();
 991   }
 992 
 993   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 994   // Goto and Return.  This call also returns the block ending Node.
 995   virtual const Node *is_block_proj() const;
 996 
 997   // The node is a "macro" node which needs to be expanded before matching
 998   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 999   // The node is expensive: the best control is set during loop opts
1000   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
1001 
1002   // An arithmetic node which accumulates a data in a loop.
1003   // It must have the loop's phi as input and provide a def to the phi.
1004   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
1005 
1006   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
1007 
1008   bool is_predicated_using_blend() const { return (_flags & Flag_is_predicated_using_blend) != 0; }
1009 
1010   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
1011   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
1012 
1013   // Used in lcm to mark nodes that have scheduled
1014   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1015 
1016   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1017 
1018 //----------------- Optimization
1019 
1020   // Get the worst-case Type output for this Node.
1021   virtual const class Type *bottom_type() const;
1022 
1023   // If we find a better type for a node, try to record it permanently.
1024   // Return true if this node actually changed.
1025   // Be sure to do the hash_delete game in the "rehash" variant.
1026   void raise_bottom_type(const Type* new_type);
1027 
1028   // Get the address type with which this node uses and/or defs memory,
1029   // or NULL if none.  The address type is conservatively wide.
1030   // Returns non-null for calls, membars, loads, stores, etc.
1031   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1032   virtual const class TypePtr *adr_type() const { return NULL; }
1033 
1034   // Return an existing node which computes the same function as this node.
1035   // The optimistic combined algorithm requires this to return a Node which
1036   // is a small number of steps away (e.g., one of my inputs).
1037   virtual Node* Identity(PhaseGVN* phase);
1038 
1039   // Return the set of values this Node can take on at runtime.
1040   virtual const Type* Value(PhaseGVN* phase) const;
1041 
1042   // Return a node which is more "ideal" than the current node.
1043   // The invariants on this call are subtle.  If in doubt, read the
1044   // treatise in node.cpp above the default implementation AND TEST WITH
1045   // +VerifyIterativeGVN!
1046   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1047 
1048   // Some nodes have specific Ideal subgraph transformations only if they are
1049   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1050   // for the transformations to happen.
1051   bool has_special_unique_user() const;
1052 
1053   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1054   Node* find_exact_control(Node* ctrl);
1055 
1056   // Check if 'this' node dominates or equal to 'sub'.
1057   bool dominates(Node* sub, Node_List &nlist);
1058 
1059 protected:
1060   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1061 public:
1062 
1063   // See if there is valid pipeline info
1064   static  const Pipeline *pipeline_class();
1065   virtual const Pipeline *pipeline() const;
1066 
1067   // Compute the latency from the def to this instruction of the ith input node
1068   uint latency(uint i);
1069 
1070   // Hash & compare functions, for pessimistic value numbering
1071 
1072   // If the hash function returns the special sentinel value NO_HASH,
1073   // the node is guaranteed never to compare equal to any other node.
1074   // If we accidentally generate a hash with value NO_HASH the node
1075   // won't go into the table and we'll lose a little optimization.
1076   static const uint NO_HASH = 0;
1077   virtual uint hash() const;
1078   virtual bool cmp( const Node &n ) const;
1079 
1080   // Operation appears to be iteratively computed (such as an induction variable)
1081   // It is possible for this operation to return false for a loop-varying
1082   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1083   bool is_iteratively_computed();
1084 
1085   // Determine if a node is a counted loop induction variable.
1086   // NOTE: The method is defined in "loopnode.cpp".
1087   bool is_cloop_ind_var() const;
1088 
1089   // Return a node with opcode "opc" and same inputs as "this" if one can
1090   // be found; Otherwise return NULL;
1091   Node* find_similar(int opc);
1092 
1093   // Return the unique control out if only one. Null if none or more than one.
1094   Node* unique_ctrl_out_or_null() const;
1095   // Return the unique control out. Asserts if none or more than one control out.
1096   Node* unique_ctrl_out() const;
1097 
1098   // Set control or add control as precedence edge
1099   void ensure_control_or_add_prec(Node* c);
1100 
1101 //----------------- Code Generation
1102 
1103   // Ideal register class for Matching.  Zero means unmatched instruction
1104   // (these are cloned instead of converted to machine nodes).
1105   virtual uint ideal_reg() const;
1106 
1107   static const uint NotAMachineReg;   // must be > max. machine register
1108 
1109   // Do we Match on this edge index or not?  Generally false for Control
1110   // and true for everything else.  Weird for calls & returns.
1111   virtual uint match_edge(uint idx) const;
1112 
1113   // Register class output is returned in
1114   virtual const RegMask &out_RegMask() const;
1115   // Register class input is expected in
1116   virtual const RegMask &in_RegMask(uint) const;
1117   // Should we clone rather than spill this instruction?
1118   bool rematerialize() const;
1119 
1120   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1121   virtual JVMState* jvms() const;
1122 
1123   // Print as assembly
1124   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1125   // Emit bytes starting at parameter 'ptr'
1126   // Bump 'ptr' by the number of output bytes
1127   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1128   // Size of instruction in bytes
1129   virtual uint size(PhaseRegAlloc *ra_) const;
1130 
1131   // Convenience function to extract an integer constant from a node.
1132   // If it is not an integer constant (either Con, CastII, or Mach),
1133   // return value_if_unknown.
1134   jint find_int_con(jint value_if_unknown) const {
1135     const TypeInt* t = find_int_type();
1136     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1137   }
1138   // Return the constant, knowing it is an integer constant already
1139   jint get_int() const {
1140     const TypeInt* t = find_int_type();
1141     guarantee(t != NULL, "must be con");
1142     return t->get_con();
1143   }
1144   // Here's where the work is done.  Can produce non-constant int types too.
1145   const TypeInt* find_int_type() const;
1146   const TypeInteger* find_integer_type(BasicType bt) const;
1147 
1148   // Same thing for long (and intptr_t, via type.hpp):
1149   jlong get_long() const {
1150     const TypeLong* t = find_long_type();
1151     guarantee(t != NULL, "must be con");
1152     return t->get_con();
1153   }
1154   jlong find_long_con(jint value_if_unknown) const {
1155     const TypeLong* t = find_long_type();
1156     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1157   }
1158   const TypeLong* find_long_type() const;
1159 
1160   jlong get_integer_as_long(BasicType bt) const {
1161     const TypeInteger* t = find_integer_type(bt);
1162     guarantee(t != NULL && t->is_con(), "must be con");
1163     return t->get_con_as_long(bt);
1164   }
1165   jlong find_integer_as_long(BasicType bt, jlong value_if_unknown) const {
1166     const TypeInteger* t = find_integer_type(bt);
1167     if (t == NULL || !t->is_con())  return value_if_unknown;
1168     return t->get_con_as_long(bt);
1169   }
1170   const TypePtr* get_ptr_type() const;
1171 
1172   // These guys are called by code generated by ADLC:
1173   intptr_t get_ptr() const;
1174   intptr_t get_narrowcon() const;
1175   jdouble getd() const;
1176   jfloat getf() const;
1177 
1178   // Nodes which are pinned into basic blocks
1179   virtual bool pinned() const { return false; }
1180 
1181   // Nodes which use memory without consuming it, hence need antidependences
1182   // More specifically, needs_anti_dependence_check returns true iff the node
1183   // (a) does a load, and (b) does not perform a store (except perhaps to a
1184   // stack slot or some other unaliased location).
1185   bool needs_anti_dependence_check() const;
1186 
1187   // Return which operand this instruction may cisc-spill. In other words,
1188   // return operand position that can convert from reg to memory access
1189   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1190   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1191 
1192   // Whether this is a memory-writing machine node.
1193   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1194 
1195 //----------------- Printing, etc
1196 #ifndef PRODUCT
1197  private:
1198   int _indent;
1199 
1200  public:
1201   void set_indent(int indent) { _indent = indent; }
1202 
1203  private:
1204   static bool add_to_worklist(Node* n, Node_List* worklist, Arena* old_arena, VectorSet* old_space, VectorSet* new_space);
1205 public:
1206   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1207   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1208   void dump() const { dump("\n"); }  // Print this node.
1209   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1210   void dump(int depth) const;        // Print this node, recursively to depth d
1211   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1212   void dump_comp() const;            // Print this node in compact representation.
1213   // Print this node in compact representation.
1214   void dump_comp(const char* suffix, outputStream *st = tty) const;
1215   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1216   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1217   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1218   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1219   // Print compact per-node info
1220   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1221   void dump_related() const;             // Print related nodes (depends on node at hand).
1222   // Print related nodes up to given depths for input and output nodes.
1223   void dump_related(uint d_in, uint d_out) const;
1224   void dump_related_compact() const;     // Print related nodes in compact representation.
1225   // Collect related nodes.
1226   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1227   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1228   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1229 
1230   // Node collectors, to be used in implementations of Node::rel().
1231   // Collect the entire data input graph. Include control inputs if requested.
1232   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1233   // Collect the entire control input graph. Include data inputs if requested.
1234   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1235   // Collect the entire output graph until hitting and including control nodes.
1236   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1237 
1238   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1239   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1240 
1241   // This call defines a class-unique string used to identify class instances
1242   virtual const char *Name() const;
1243 
1244   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1245   // RegMask Print Functions
1246   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1247   void dump_out_regmask() { out_RegMask().dump(); }
1248   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1249   void fast_dump() const {
1250     tty->print("%4d: %-17s", _idx, Name());
1251     for (uint i = 0; i < len(); i++)
1252       if (in(i))
1253         tty->print(" %4d", in(i)->_idx);
1254       else
1255         tty->print(" NULL");
1256     tty->print("\n");
1257   }
1258 #endif
1259 #ifdef ASSERT
1260   void verify_construction();
1261   bool verify_jvms(const JVMState* jvms) const;
1262 
1263   Node* _debug_orig;                   // Original version of this, if any.
1264   Node*  debug_orig() const            { return _debug_orig; }
1265   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1266   void   dump_orig(outputStream *st, bool print_key = true) const;
1267 
1268   int  _debug_idx;                     // Unique value assigned to every node.
1269   int   debug_idx() const              { return _debug_idx; }
1270   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1271 
1272   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1273   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1274   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1275 
1276   static void init_NodeProperty();
1277 
1278   #if OPTO_DU_ITERATOR_ASSERT
1279   const Node* _last_del;               // The last deleted node.
1280   uint        _del_tick;               // Bumped when a deletion happens..
1281   #endif
1282 #endif
1283 };
1284 
1285 inline bool not_a_node(const Node* n) {
1286   if (n == NULL)                   return true;
1287   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1288   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1289   return false;
1290 }
1291 
1292 //-----------------------------------------------------------------------------
1293 // Iterators over DU info, and associated Node functions.
1294 
1295 #if OPTO_DU_ITERATOR_ASSERT
1296 
1297 // Common code for assertion checking on DU iterators.
1298 class DUIterator_Common {
1299 #ifdef ASSERT
1300  protected:
1301   bool         _vdui;               // cached value of VerifyDUIterators
1302   const Node*  _node;               // the node containing the _out array
1303   uint         _outcnt;             // cached node->_outcnt
1304   uint         _del_tick;           // cached node->_del_tick
1305   Node*        _last;               // last value produced by the iterator
1306 
1307   void sample(const Node* node);    // used by c'tor to set up for verifies
1308   void verify(const Node* node, bool at_end_ok = false);
1309   void verify_resync();
1310   void reset(const DUIterator_Common& that);
1311 
1312 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1313   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1314 #else
1315   #define I_VDUI_ONLY(i,x) { }
1316 #endif //ASSERT
1317 };
1318 
1319 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1320 
1321 // Default DU iterator.  Allows appends onto the out array.
1322 // Allows deletion from the out array only at the current point.
1323 // Usage:
1324 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1325 //    Node* y = x->out(i);
1326 //    ...
1327 //  }
1328 // Compiles in product mode to a unsigned integer index, which indexes
1329 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1330 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1331 // before continuing the loop.  You must delete only the last-produced
1332 // edge.  You must delete only a single copy of the last-produced edge,
1333 // or else you must delete all copies at once (the first time the edge
1334 // is produced by the iterator).
1335 class DUIterator : public DUIterator_Common {
1336   friend class Node;
1337 
1338   // This is the index which provides the product-mode behavior.
1339   // Whatever the product-mode version of the system does to the
1340   // DUI index is done to this index.  All other fields in
1341   // this class are used only for assertion checking.
1342   uint         _idx;
1343 
1344   #ifdef ASSERT
1345   uint         _refresh_tick;    // Records the refresh activity.
1346 
1347   void sample(const Node* node); // Initialize _refresh_tick etc.
1348   void verify(const Node* node, bool at_end_ok = false);
1349   void verify_increment();       // Verify an increment operation.
1350   void verify_resync();          // Verify that we can back up over a deletion.
1351   void verify_finish();          // Verify that the loop terminated properly.
1352   void refresh();                // Resample verification info.
1353   void reset(const DUIterator& that);  // Resample after assignment.
1354   #endif
1355 
1356   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1357     { _idx = 0;                         debug_only(sample(node)); }
1358 
1359  public:
1360   // initialize to garbage; clear _vdui to disable asserts
1361   DUIterator()
1362     { /*initialize to garbage*/         debug_only(_vdui = false); }
1363 
1364   DUIterator(const DUIterator& that)
1365     { _idx = that._idx;                 debug_only(_vdui = false; reset(that)); }
1366 
1367   void operator++(int dummy_to_specify_postfix_op)
1368     { _idx++;                           VDUI_ONLY(verify_increment()); }
1369 
1370   void operator--()
1371     { VDUI_ONLY(verify_resync());       --_idx; }
1372 
1373   ~DUIterator()
1374     { VDUI_ONLY(verify_finish()); }
1375 
1376   void operator=(const DUIterator& that)
1377     { _idx = that._idx;                 debug_only(reset(that)); }
1378 };
1379 
1380 DUIterator Node::outs() const
1381   { return DUIterator(this, 0); }
1382 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1383   { I_VDUI_ONLY(i, i.refresh());        return i; }
1384 bool Node::has_out(DUIterator& i) const
1385   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1386 Node*    Node::out(DUIterator& i) const
1387   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1388 
1389 
1390 // Faster DU iterator.  Disallows insertions into the out array.
1391 // Allows deletion from the out array only at the current point.
1392 // Usage:
1393 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1394 //    Node* y = x->fast_out(i);
1395 //    ...
1396 //  }
1397 // Compiles in product mode to raw Node** pointer arithmetic, with
1398 // no reloading of pointers from the original node x.  If you delete,
1399 // you must perform "--i; --imax" just before continuing the loop.
1400 // If you delete multiple copies of the same edge, you must decrement
1401 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1402 class DUIterator_Fast : public DUIterator_Common {
1403   friend class Node;
1404   friend class DUIterator_Last;
1405 
1406   // This is the pointer which provides the product-mode behavior.
1407   // Whatever the product-mode version of the system does to the
1408   // DUI pointer is done to this pointer.  All other fields in
1409   // this class are used only for assertion checking.
1410   Node**       _outp;
1411 
1412   #ifdef ASSERT
1413   void verify(const Node* node, bool at_end_ok = false);
1414   void verify_limit();
1415   void verify_resync();
1416   void verify_relimit(uint n);
1417   void reset(const DUIterator_Fast& that);
1418   #endif
1419 
1420   // Note:  offset must be signed, since -1 is sometimes passed
1421   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1422     { _outp = node->_out + offset;      debug_only(sample(node)); }
1423 
1424  public:
1425   // initialize to garbage; clear _vdui to disable asserts
1426   DUIterator_Fast()
1427     { /*initialize to garbage*/         debug_only(_vdui = false); }
1428 
1429   DUIterator_Fast(const DUIterator_Fast& that)
1430     { _outp = that._outp;               debug_only(_vdui = false; reset(that)); }
1431 
1432   void operator++(int dummy_to_specify_postfix_op)
1433     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1434 
1435   void operator--()
1436     { VDUI_ONLY(verify_resync());       --_outp; }
1437 
1438   void operator-=(uint n)   // applied to the limit only
1439     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1440 
1441   bool operator<(DUIterator_Fast& limit) {
1442     I_VDUI_ONLY(*this, this->verify(_node, true));
1443     I_VDUI_ONLY(limit, limit.verify_limit());
1444     return _outp < limit._outp;
1445   }
1446 
1447   void operator=(const DUIterator_Fast& that)
1448     { _outp = that._outp;               debug_only(reset(that)); }
1449 };
1450 
1451 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1452   // Assign a limit pointer to the reference argument:
1453   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1454   // Return the base pointer:
1455   return DUIterator_Fast(this, 0);
1456 }
1457 Node* Node::fast_out(DUIterator_Fast& i) const {
1458   I_VDUI_ONLY(i, i.verify(this));
1459   return debug_only(i._last=) *i._outp;
1460 }
1461 
1462 
1463 // Faster DU iterator.  Requires each successive edge to be removed.
1464 // Does not allow insertion of any edges.
1465 // Usage:
1466 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1467 //    Node* y = x->last_out(i);
1468 //    ...
1469 //  }
1470 // Compiles in product mode to raw Node** pointer arithmetic, with
1471 // no reloading of pointers from the original node x.
1472 class DUIterator_Last : private DUIterator_Fast {
1473   friend class Node;
1474 
1475   #ifdef ASSERT
1476   void verify(const Node* node, bool at_end_ok = false);
1477   void verify_limit();
1478   void verify_step(uint num_edges);
1479   #endif
1480 
1481   // Note:  offset must be signed, since -1 is sometimes passed
1482   DUIterator_Last(const Node* node, ptrdiff_t offset)
1483     : DUIterator_Fast(node, offset) { }
1484 
1485   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1486   void operator<(int)                              {} // do not use
1487 
1488  public:
1489   DUIterator_Last() { }
1490   // initialize to garbage
1491 
1492   DUIterator_Last(const DUIterator_Last& that) = default;
1493 
1494   void operator--()
1495     { _outp--;              VDUI_ONLY(verify_step(1));  }
1496 
1497   void operator-=(uint n)
1498     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1499 
1500   bool operator>=(DUIterator_Last& limit) {
1501     I_VDUI_ONLY(*this, this->verify(_node, true));
1502     I_VDUI_ONLY(limit, limit.verify_limit());
1503     return _outp >= limit._outp;
1504   }
1505 
1506   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1507 };
1508 
1509 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1510   // Assign a limit pointer to the reference argument:
1511   imin = DUIterator_Last(this, 0);
1512   // Return the initial pointer:
1513   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1514 }
1515 Node* Node::last_out(DUIterator_Last& i) const {
1516   I_VDUI_ONLY(i, i.verify(this));
1517   return debug_only(i._last=) *i._outp;
1518 }
1519 
1520 #endif //OPTO_DU_ITERATOR_ASSERT
1521 
1522 #undef I_VDUI_ONLY
1523 #undef VDUI_ONLY
1524 
1525 // An Iterator that truly follows the iterator pattern.  Doesn't
1526 // support deletion but could be made to.
1527 //
1528 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1529 //     Node* m = i.get();
1530 //
1531 class SimpleDUIterator : public StackObj {
1532  private:
1533   Node* node;
1534   DUIterator_Fast i;
1535   DUIterator_Fast imax;
1536  public:
1537   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1538   bool has_next() { return i < imax; }
1539   void next() { i++; }
1540   Node* get() { return node->fast_out(i); }
1541 };
1542 
1543 
1544 //-----------------------------------------------------------------------------
1545 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1546 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1547 // Note that the constructor just zeros things, and since I use Arena
1548 // allocation I do not need a destructor to reclaim storage.
1549 class Node_Array : public ResourceObj {
1550   friend class VMStructs;
1551 protected:
1552   Arena* _a;                    // Arena to allocate in
1553   uint   _max;
1554   Node** _nodes;
1555   void   grow( uint i );        // Grow array node to fit
1556 public:
1557   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1558     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1559     clear();
1560   }
1561 
1562   Node_Array(Node_Array* na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1563   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1564   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1565   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1566   Node** adr() { return _nodes; }
1567   // Extend the mapping: index i maps to Node *n.
1568   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1569   void insert( uint i, Node *n );
1570   void remove( uint i );        // Remove, preserving order
1571   // Clear all entries in _nodes to NULL but keep storage
1572   void clear() {
1573     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1574   }
1575 
1576   uint Size() const { return _max; }
1577   void dump() const;
1578 };
1579 
1580 class Node_List : public Node_Array {
1581   friend class VMStructs;
1582   uint _cnt;
1583 public:
1584   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1585   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1586   bool contains(const Node* n) const {
1587     for (uint e = 0; e < size(); e++) {
1588       if (at(e) == n) return true;
1589     }
1590     return false;
1591   }
1592   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1593   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1594   void push( Node *b ) { map(_cnt++,b); }
1595   void yank( Node *n );         // Find and remove
1596   Node *pop() { return _nodes[--_cnt]; }
1597   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1598   void copy(const Node_List& from) {
1599     if (from._max > _max) {
1600       grow(from._max);
1601     }
1602     _cnt = from._cnt;
1603     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1604   }
1605 
1606   uint size() const { return _cnt; }
1607   void dump() const;
1608   void dump_simple() const;
1609 };
1610 
1611 //------------------------------Unique_Node_List-------------------------------
1612 class Unique_Node_List : public Node_List {
1613   friend class VMStructs;
1614   VectorSet _in_worklist;
1615   uint _clock_index;            // Index in list where to pop from next
1616 public:
1617   Unique_Node_List() : Node_List(), _clock_index(0) {}
1618   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1619 
1620   void remove( Node *n );
1621   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1622   VectorSet& member_set(){ return _in_worklist; }
1623 
1624   void push(Node* b) {
1625     if( !_in_worklist.test_set(b->_idx) )
1626       Node_List::push(b);
1627   }
1628   Node *pop() {
1629     if( _clock_index >= size() ) _clock_index = 0;
1630     Node *b = at(_clock_index);
1631     map( _clock_index, Node_List::pop());
1632     if (size() != 0) _clock_index++; // Always start from 0
1633     _in_worklist.remove(b->_idx);
1634     return b;
1635   }
1636   Node *remove(uint i) {
1637     Node *b = Node_List::at(i);
1638     _in_worklist.remove(b->_idx);
1639     map(i,Node_List::pop());
1640     return b;
1641   }
1642   void yank(Node *n) {
1643     _in_worklist.remove(n->_idx);
1644     Node_List::yank(n);
1645   }
1646   void  clear() {
1647     _in_worklist.clear();        // Discards storage but grows automatically
1648     Node_List::clear();
1649     _clock_index = 0;
1650   }
1651 
1652   // Used after parsing to remove useless nodes before Iterative GVN
1653   void remove_useless_nodes(VectorSet& useful);
1654 
1655   bool contains(const Node* n) const {
1656     fatal("use faster member() instead");
1657     return false;
1658   }
1659 
1660 #ifndef PRODUCT
1661   void print_set() const { _in_worklist.print(); }
1662 #endif
1663 };
1664 
1665 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1666 inline void Compile::record_for_igvn(Node* n) {
1667   _for_igvn->push(n);
1668 }
1669 
1670 //------------------------------Node_Stack-------------------------------------
1671 class Node_Stack {
1672   friend class VMStructs;
1673 protected:
1674   struct INode {
1675     Node *node; // Processed node
1676     uint  indx; // Index of next node's child
1677   };
1678   INode *_inode_top; // tos, stack grows up
1679   INode *_inode_max; // End of _inodes == _inodes + _max
1680   INode *_inodes;    // Array storage for the stack
1681   Arena *_a;         // Arena to allocate in
1682   void grow();
1683 public:
1684   Node_Stack(int size) {
1685     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1686     _a = Thread::current()->resource_area();
1687     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1688     _inode_max = _inodes + max;
1689     _inode_top = _inodes - 1; // stack is empty
1690   }
1691 
1692   Node_Stack(Arena *a, int size) : _a(a) {
1693     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1694     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1695     _inode_max = _inodes + max;
1696     _inode_top = _inodes - 1; // stack is empty
1697   }
1698 
1699   void pop() {
1700     assert(_inode_top >= _inodes, "node stack underflow");
1701     --_inode_top;
1702   }
1703   void push(Node *n, uint i) {
1704     ++_inode_top;
1705     if (_inode_top >= _inode_max) grow();
1706     INode *top = _inode_top; // optimization
1707     top->node = n;
1708     top->indx = i;
1709   }
1710   Node *node() const {
1711     return _inode_top->node;
1712   }
1713   Node* node_at(uint i) const {
1714     assert(_inodes + i <= _inode_top, "in range");
1715     return _inodes[i].node;
1716   }
1717   uint index() const {
1718     return _inode_top->indx;
1719   }
1720   uint index_at(uint i) const {
1721     assert(_inodes + i <= _inode_top, "in range");
1722     return _inodes[i].indx;
1723   }
1724   void set_node(Node *n) {
1725     _inode_top->node = n;
1726   }
1727   void set_index(uint i) {
1728     _inode_top->indx = i;
1729   }
1730   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1731   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1732   bool is_nonempty() const { return (_inode_top >= _inodes); }
1733   bool is_empty() const { return (_inode_top < _inodes); }
1734   void clear() { _inode_top = _inodes - 1; } // retain storage
1735 
1736   // Node_Stack is used to map nodes.
1737   Node* find(uint idx) const;
1738 };
1739 
1740 
1741 //-----------------------------Node_Notes--------------------------------------
1742 // Debugging or profiling annotations loosely and sparsely associated
1743 // with some nodes.  See Compile::node_notes_at for the accessor.
1744 class Node_Notes {
1745   friend class VMStructs;
1746   JVMState* _jvms;
1747 
1748 public:
1749   Node_Notes(JVMState* jvms = NULL) {
1750     _jvms = jvms;
1751   }
1752 
1753   JVMState* jvms()            { return _jvms; }
1754   void  set_jvms(JVMState* x) {        _jvms = x; }
1755 
1756   // True if there is nothing here.
1757   bool is_clear() {
1758     return (_jvms == NULL);
1759   }
1760 
1761   // Make there be nothing here.
1762   void clear() {
1763     _jvms = NULL;
1764   }
1765 
1766   // Make a new, clean node notes.
1767   static Node_Notes* make(Compile* C) {
1768     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1769     nn->clear();
1770     return nn;
1771   }
1772 
1773   Node_Notes* clone(Compile* C) {
1774     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1775     (*nn) = (*this);
1776     return nn;
1777   }
1778 
1779   // Absorb any information from source.
1780   bool update_from(Node_Notes* source) {
1781     bool changed = false;
1782     if (source != NULL) {
1783       if (source->jvms() != NULL) {
1784         set_jvms(source->jvms());
1785         changed = true;
1786       }
1787     }
1788     return changed;
1789   }
1790 };
1791 
1792 // Inlined accessors for Compile::node_nodes that require the preceding class:
1793 inline Node_Notes*
1794 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1795                            int idx, bool can_grow) {
1796   assert(idx >= 0, "oob");
1797   int block_idx = (idx >> _log2_node_notes_block_size);
1798   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1799   if (grow_by >= 0) {
1800     if (!can_grow) return NULL;
1801     grow_node_notes(arr, grow_by + 1);
1802   }
1803   if (arr == NULL) return NULL;
1804   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1805   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1806 }
1807 
1808 inline bool
1809 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1810   if (value == NULL || value->is_clear())
1811     return false;  // nothing to write => write nothing
1812   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1813   assert(loc != NULL, "");
1814   return loc->update_from(value);
1815 }
1816 
1817 
1818 //------------------------------TypeNode---------------------------------------
1819 // Node with a Type constant.
1820 class TypeNode : public Node {
1821 protected:
1822   virtual uint hash() const;    // Check the type
1823   virtual bool cmp( const Node &n ) const;
1824   virtual uint size_of() const; // Size is bigger
1825   const Type* const _type;
1826 public:
1827   void set_type(const Type* t) {
1828     assert(t != NULL, "sanity");
1829     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1830     *(const Type**)&_type = t;   // cast away const-ness
1831     // If this node is in the hash table, make sure it doesn't need a rehash.
1832     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1833   }
1834   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1835   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1836     init_class_id(Class_Type);
1837   }
1838   virtual const Type* Value(PhaseGVN* phase) const;
1839   virtual const Type *bottom_type() const;
1840   virtual       uint  ideal_reg() const;
1841 #ifndef PRODUCT
1842   virtual void dump_spec(outputStream *st) const;
1843   virtual void dump_compact_spec(outputStream *st) const;
1844 #endif
1845 };
1846 
1847 #include "opto/opcodes.hpp"
1848 
1849 #define Op_IL(op) \
1850   inline int Op_ ## op(BasicType bt) { \
1851   assert(bt == T_INT || bt == T_LONG, "only for int or longs"); \
1852   if (bt == T_INT) { \
1853     return Op_## op ## I; \
1854   } \
1855   return Op_## op ## L; \
1856 }
1857 
1858 Op_IL(Add)
1859 Op_IL(Sub)
1860 Op_IL(Mul)
1861 Op_IL(URShift)
1862 Op_IL(LShift)
1863 Op_IL(Xor)
1864 Op_IL(Cmp)
1865 
1866 inline int Op_ConIL(BasicType bt) {
1867   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
1868   if (bt == T_INT) {
1869     return Op_ConI;
1870   }
1871   return Op_ConL;
1872 }
1873 
1874 inline int Op_Cmp_unsigned(BasicType bt) {
1875   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
1876   if (bt == T_INT) {
1877     return Op_CmpU;
1878   }
1879   return Op_CmpUL;
1880 }
1881 
1882 inline int Op_Cast(BasicType bt) {
1883   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
1884   if (bt == T_INT) {
1885     return Op_CastII;
1886   }
1887   return Op_CastLL;
1888 }
1889 
1890 #endif // SHARE_OPTO_NODE_HPP