1 /*
   2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_OPTO_NODE_HPP
  26 #define SHARE_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 #include "utilities/copy.hpp"
  32 
  33 // Portions of code courtesy of Clifford Click
  34 
  35 // Optimization - Graph Style
  36 
  37 
  38 class AbstractLockNode;
  39 class AddNode;
  40 class AddPNode;
  41 class AliasInfo;
  42 class AllocateArrayNode;
  43 class AllocateNode;
  44 class ArrayCopyNode;
  45 class BaseCountedLoopNode;
  46 class BaseCountedLoopEndNode;
  47 class BlackholeNode;
  48 class Block;
  49 class BoolNode;
  50 class BoxLockNode;
  51 class CMoveNode;
  52 class CallDynamicJavaNode;
  53 class CallJavaNode;
  54 class CallLeafNode;
  55 class CallLeafNoFPNode;
  56 class CallNode;
  57 class CallRuntimeNode;
  58 class CallNativeNode;
  59 class CallStaticJavaNode;
  60 class CastFFNode;
  61 class CastDDNode;
  62 class CastVVNode;
  63 class CastIINode;
  64 class CastLLNode;
  65 class CatchNode;
  66 class CatchProjNode;
  67 class CheckCastPPNode;
  68 class ClearArrayNode;
  69 class CmpNode;
  70 class CodeBuffer;
  71 class ConstraintCastNode;
  72 class ConNode;
  73 class CompareAndSwapNode;
  74 class CompareAndExchangeNode;
  75 class CountedLoopNode;
  76 class CountedLoopEndNode;
  77 class DecodeNarrowPtrNode;
  78 class DecodeNNode;
  79 class DecodeNKlassNode;
  80 class EncodeNarrowPtrNode;
  81 class EncodePNode;
  82 class EncodePKlassNode;
  83 class FastLockNode;
  84 class FastUnlockNode;
  85 class HaltNode;
  86 class IfNode;
  87 class IfProjNode;
  88 class IfFalseNode;
  89 class IfTrueNode;
  90 class InitializeNode;
  91 class JVMState;
  92 class JumpNode;
  93 class JumpProjNode;
  94 class LoadNode;
  95 class LoadStoreNode;
  96 class LoadStoreConditionalNode;
  97 class LockNode;
  98 class LongCountedLoopNode;
  99 class LongCountedLoopEndNode;
 100 class LoopNode;
 101 class MachBranchNode;
 102 class MachCallDynamicJavaNode;
 103 class MachCallJavaNode;
 104 class MachCallLeafNode;
 105 class MachCallNode;
 106 class MachCallNativeNode;
 107 class MachCallRuntimeNode;
 108 class MachCallStaticJavaNode;
 109 class MachConstantBaseNode;
 110 class MachConstantNode;
 111 class MachGotoNode;
 112 class MachIfNode;
 113 class MachJumpNode;
 114 class MachNode;
 115 class MachNullCheckNode;
 116 class MachProjNode;
 117 class MachReturnNode;
 118 class MachSafePointNode;
 119 class MachSpillCopyNode;
 120 class MachTempNode;
 121 class MachMergeNode;
 122 class MachMemBarNode;
 123 class Matcher;
 124 class MemBarNode;
 125 class MemBarStoreStoreNode;
 126 class MemNode;
 127 class MergeMemNode;
 128 class MoveNode;
 129 class MulNode;
 130 class MultiNode;
 131 class MultiBranchNode;
 132 class NeverBranchNode;
 133 class Opaque1Node;
 134 class OuterStripMinedLoopNode;
 135 class OuterStripMinedLoopEndNode;
 136 class Node;
 137 class Node_Array;
 138 class Node_List;
 139 class Node_Stack;
 140 class OopMap;
 141 class ParmNode;
 142 class PCTableNode;
 143 class PhaseCCP;
 144 class PhaseGVN;
 145 class PhaseIterGVN;
 146 class PhaseRegAlloc;
 147 class PhaseTransform;
 148 class PhaseValues;
 149 class PhiNode;
 150 class Pipeline;
 151 class ProjNode;
 152 class RangeCheckNode;
 153 class RegMask;
 154 class RegionNode;
 155 class RootNode;
 156 class SafePointNode;
 157 class SafePointScalarObjectNode;
 158 class StartNode;
 159 class State;
 160 class StoreNode;
 161 class SubNode;
 162 class SubTypeCheckNode;
 163 class Type;
 164 class TypeNode;
 165 class UnlockNode;
 166 class VectorNode;
 167 class LoadVectorNode;
 168 class LoadVectorMaskedNode;
 169 class StoreVectorMaskedNode;
 170 class LoadVectorGatherNode;
 171 class StoreVectorNode;
 172 class StoreVectorScatterNode;
 173 class VectorMaskCmpNode;
 174 class VectorSet;
 175 
 176 // The type of all node counts and indexes.
 177 // It must hold at least 16 bits, but must also be fast to load and store.
 178 // This type, if less than 32 bits, could limit the number of possible nodes.
 179 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 180 typedef unsigned int node_idx_t;
 181 
 182 
 183 #ifndef OPTO_DU_ITERATOR_ASSERT
 184 #ifdef ASSERT
 185 #define OPTO_DU_ITERATOR_ASSERT 1
 186 #else
 187 #define OPTO_DU_ITERATOR_ASSERT 0
 188 #endif
 189 #endif //OPTO_DU_ITERATOR_ASSERT
 190 
 191 #if OPTO_DU_ITERATOR_ASSERT
 192 class DUIterator;
 193 class DUIterator_Fast;
 194 class DUIterator_Last;
 195 #else
 196 typedef uint   DUIterator;
 197 typedef Node** DUIterator_Fast;
 198 typedef Node** DUIterator_Last;
 199 #endif
 200 
 201 // Node Sentinel
 202 #define NodeSentinel (Node*)-1
 203 
 204 // Unknown count frequency
 205 #define COUNT_UNKNOWN (-1.0f)
 206 
 207 //------------------------------Node-------------------------------------------
 208 // Nodes define actions in the program.  They create values, which have types.
 209 // They are both vertices in a directed graph and program primitives.  Nodes
 210 // are labeled; the label is the "opcode", the primitive function in the lambda
 211 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 212 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 213 // the Node's function.  These inputs also define a Type equation for the Node.
 214 // Solving these Type equations amounts to doing dataflow analysis.
 215 // Control and data are uniformly represented in the graph.  Finally, Nodes
 216 // have a unique dense integer index which is used to index into side arrays
 217 // whenever I have phase-specific information.
 218 
 219 class Node {
 220   friend class VMStructs;
 221 
 222   // Lots of restrictions on cloning Nodes
 223   NONCOPYABLE(Node);
 224 
 225 public:
 226   friend class Compile;
 227   #if OPTO_DU_ITERATOR_ASSERT
 228   friend class DUIterator_Common;
 229   friend class DUIterator;
 230   friend class DUIterator_Fast;
 231   friend class DUIterator_Last;
 232   #endif
 233 
 234   // Because Nodes come and go, I define an Arena of Node structures to pull
 235   // from.  This should allow fast access to node creation & deletion.  This
 236   // field is a local cache of a value defined in some "program fragment" for
 237   // which these Nodes are just a part of.
 238 
 239   inline void* operator new(size_t x) throw() {
 240     Compile* C = Compile::current();
 241     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 242     return (void*)n;
 243   }
 244 
 245   // Delete is a NOP
 246   void operator delete( void *ptr ) {}
 247   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 248   void destruct(PhaseValues* phase);
 249 
 250   // Create a new Node.  Required is the number is of inputs required for
 251   // semantic correctness.
 252   Node( uint required );
 253 
 254   // Create a new Node with given input edges.
 255   // This version requires use of the "edge-count" new.
 256   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 257   Node( Node *n0 );
 258   Node( Node *n0, Node *n1 );
 259   Node( Node *n0, Node *n1, Node *n2 );
 260   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 261   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 262   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 263   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 264             Node *n4, Node *n5, Node *n6 );
 265 
 266   // Clone an inherited Node given only the base Node type.
 267   Node* clone() const;
 268 
 269   // Clone a Node, immediately supplying one or two new edges.
 270   // The first and second arguments, if non-null, replace in(1) and in(2),
 271   // respectively.
 272   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 273     Node* nn = clone();
 274     if (in1 != NULL)  nn->set_req(1, in1);
 275     if (in2 != NULL)  nn->set_req(2, in2);
 276     return nn;
 277   }
 278 
 279 private:
 280   // Shared setup for the above constructors.
 281   // Handles all interactions with Compile::current.
 282   // Puts initial values in all Node fields except _idx.
 283   // Returns the initial value for _idx, which cannot
 284   // be initialized by assignment.
 285   inline int Init(int req);
 286 
 287 //----------------- input edge handling
 288 protected:
 289   friend class PhaseCFG;        // Access to address of _in array elements
 290   Node **_in;                   // Array of use-def references to Nodes
 291   Node **_out;                  // Array of def-use references to Nodes
 292 
 293   // Input edges are split into two categories.  Required edges are required
 294   // for semantic correctness; order is important and NULLs are allowed.
 295   // Precedence edges are used to help determine execution order and are
 296   // added, e.g., for scheduling purposes.  They are unordered and not
 297   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 298   // are required, from _cnt to _max-1 are precedence edges.
 299   node_idx_t _cnt;              // Total number of required Node inputs.
 300 
 301   node_idx_t _max;              // Actual length of input array.
 302 
 303   // Output edges are an unordered list of def-use edges which exactly
 304   // correspond to required input edges which point from other nodes
 305   // to this one.  Thus the count of the output edges is the number of
 306   // users of this node.
 307   node_idx_t _outcnt;           // Total number of Node outputs.
 308 
 309   node_idx_t _outmax;           // Actual length of output array.
 310 
 311   // Grow the actual input array to the next larger power-of-2 bigger than len.
 312   void grow( uint len );
 313   // Grow the output array to the next larger power-of-2 bigger than len.
 314   void out_grow( uint len );
 315 
 316  public:
 317   // Each Node is assigned a unique small/dense number.  This number is used
 318   // to index into auxiliary arrays of data and bit vectors.
 319   // The field _idx is declared constant to defend against inadvertent assignments,
 320   // since it is used by clients as a naked field. However, the field's value can be
 321   // changed using the set_idx() method.
 322   //
 323   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 324   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 325   // preserved in _parse_idx.
 326   const node_idx_t _idx;
 327   DEBUG_ONLY(const node_idx_t _parse_idx;)
 328   // IGV node identifier. Two nodes, possibly in different compilation phases,
 329   // have the same IGV identifier if (and only if) they are the very same node
 330   // (same memory address) or one is "derived" from the other (by e.g.
 331   // renumbering or matching). This identifier makes it possible to follow the
 332   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 333   NOT_PRODUCT(node_idx_t _igv_idx;)
 334 
 335   // Get the (read-only) number of input edges
 336   uint req() const { return _cnt; }
 337   uint len() const { return _max; }
 338   // Get the (read-only) number of output edges
 339   uint outcnt() const { return _outcnt; }
 340 
 341 #if OPTO_DU_ITERATOR_ASSERT
 342   // Iterate over the out-edges of this node.  Deletions are illegal.
 343   inline DUIterator outs() const;
 344   // Use this when the out array might have changed to suppress asserts.
 345   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 346   // Does the node have an out at this position?  (Used for iteration.)
 347   inline bool has_out(DUIterator& i) const;
 348   inline Node*    out(DUIterator& i) const;
 349   // Iterate over the out-edges of this node.  All changes are illegal.
 350   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 351   inline Node*    fast_out(DUIterator_Fast& i) const;
 352   // Iterate over the out-edges of this node, deleting one at a time.
 353   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 354   inline Node*    last_out(DUIterator_Last& i) const;
 355   // The inline bodies of all these methods are after the iterator definitions.
 356 #else
 357   // Iterate over the out-edges of this node.  Deletions are illegal.
 358   // This iteration uses integral indexes, to decouple from array reallocations.
 359   DUIterator outs() const  { return 0; }
 360   // Use this when the out array might have changed to suppress asserts.
 361   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 362 
 363   // Reference to the i'th output Node.  Error if out of bounds.
 364   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 365   // Does the node have an out at this position?  (Used for iteration.)
 366   bool has_out(DUIterator i) const { return i < _outcnt; }
 367 
 368   // Iterate over the out-edges of this node.  All changes are illegal.
 369   // This iteration uses a pointer internal to the out array.
 370   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 371     Node** out = _out;
 372     // Assign a limit pointer to the reference argument:
 373     max = out + (ptrdiff_t)_outcnt;
 374     // Return the base pointer:
 375     return out;
 376   }
 377   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 378   // Iterate over the out-edges of this node, deleting one at a time.
 379   // This iteration uses a pointer internal to the out array.
 380   DUIterator_Last last_outs(DUIterator_Last& min) const {
 381     Node** out = _out;
 382     // Assign a limit pointer to the reference argument:
 383     min = out;
 384     // Return the pointer to the start of the iteration:
 385     return out + (ptrdiff_t)_outcnt - 1;
 386   }
 387   Node*    last_out(DUIterator_Last i) const  { return *i; }
 388 #endif
 389 
 390   // Reference to the i'th input Node.  Error if out of bounds.
 391   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 392   // Reference to the i'th input Node.  NULL if out of bounds.
 393   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 394   // Reference to the i'th output Node.  Error if out of bounds.
 395   // Use this accessor sparingly.  We are going trying to use iterators instead.
 396   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 397   // Return the unique out edge.
 398   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 399   // Delete out edge at position 'i' by moving last out edge to position 'i'
 400   void  raw_del_out(uint i) {
 401     assert(i < _outcnt,"oob");
 402     assert(_outcnt > 0,"oob");
 403     #if OPTO_DU_ITERATOR_ASSERT
 404     // Record that a change happened here.
 405     debug_only(_last_del = _out[i]; ++_del_tick);
 406     #endif
 407     _out[i] = _out[--_outcnt];
 408     // Smash the old edge so it can't be used accidentally.
 409     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 410   }
 411 
 412 #ifdef ASSERT
 413   bool is_dead() const;
 414 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 415   bool is_reachable_from_root() const;
 416 #endif
 417   // Check whether node has become unreachable
 418   bool is_unreachable(PhaseIterGVN &igvn) const;
 419 
 420   // Set a required input edge, also updates corresponding output edge
 421   void add_req( Node *n ); // Append a NEW required input
 422   void add_req( Node *n0, Node *n1 ) {
 423     add_req(n0); add_req(n1); }
 424   void add_req( Node *n0, Node *n1, Node *n2 ) {
 425     add_req(n0); add_req(n1); add_req(n2); }
 426   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 427   void del_req( uint idx ); // Delete required edge & compact
 428   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 429   void ins_req( uint i, Node *n ); // Insert a NEW required input
 430   void set_req( uint i, Node *n ) {
 431     assert( is_not_dead(n), "can not use dead node");
 432     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 433     assert( !VerifyHashTableKeys || _hash_lock == 0,
 434             "remove node from hash table before modifying it");
 435     Node** p = &_in[i];    // cache this._in, across the del_out call
 436     if (*p != NULL)  (*p)->del_out((Node *)this);
 437     (*p) = n;
 438     if (n != NULL)      n->add_out((Node *)this);
 439     Compile::current()->record_modified_node(this);
 440   }
 441   // Light version of set_req() to init inputs after node creation.
 442   void init_req( uint i, Node *n ) {
 443     assert( i == 0 && this == n ||
 444             is_not_dead(n), "can not use dead node");
 445     assert( i < _cnt, "oob");
 446     assert( !VerifyHashTableKeys || _hash_lock == 0,
 447             "remove node from hash table before modifying it");
 448     assert( _in[i] == NULL, "sanity");
 449     _in[i] = n;
 450     if (n != NULL)      n->add_out((Node *)this);
 451     Compile::current()->record_modified_node(this);
 452   }
 453   // Find first occurrence of n among my edges:
 454   int find_edge(Node* n);
 455   int find_prec_edge(Node* n) {
 456     for (uint i = req(); i < len(); i++) {
 457       if (_in[i] == n) return i;
 458       if (_in[i] == NULL) {
 459         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 460         break;
 461       }
 462     }
 463     return -1;
 464   }
 465   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = NULL);
 466   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 467   // NULL out all inputs to eliminate incoming Def-Use edges.
 468   void disconnect_inputs(Compile* C);
 469 
 470   // Quickly, return true if and only if I am Compile::current()->top().
 471   bool is_top() const {
 472     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 473     return (_out == NULL);
 474   }
 475   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 476   void setup_is_top();
 477 
 478   // Strip away casting.  (It is depth-limited.)
 479   Node* uncast(bool keep_deps = false) const;
 480   // Return whether two Nodes are equivalent, after stripping casting.
 481   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 482     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 483   }
 484 
 485   // Find out of current node that matches opcode.
 486   Node* find_out_with(int opcode);
 487   // Return true if the current node has an out that matches opcode.
 488   bool has_out_with(int opcode);
 489   // Return true if the current node has an out that matches any of the opcodes.
 490   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 491 
 492 private:
 493   static Node* uncast_helper(const Node* n, bool keep_deps);
 494 
 495   // Add an output edge to the end of the list
 496   void add_out( Node *n ) {
 497     if (is_top())  return;
 498     if( _outcnt == _outmax ) out_grow(_outcnt);
 499     _out[_outcnt++] = n;
 500   }
 501   // Delete an output edge
 502   void del_out( Node *n ) {
 503     if (is_top())  return;
 504     Node** outp = &_out[_outcnt];
 505     // Find and remove n
 506     do {
 507       assert(outp > _out, "Missing Def-Use edge");
 508     } while (*--outp != n);
 509     *outp = _out[--_outcnt];
 510     // Smash the old edge so it can't be used accidentally.
 511     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 512     // Record that a change happened here.
 513     #if OPTO_DU_ITERATOR_ASSERT
 514     debug_only(_last_del = n; ++_del_tick);
 515     #endif
 516   }
 517   // Close gap after removing edge.
 518   void close_prec_gap_at(uint gap) {
 519     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 520     uint i = gap;
 521     Node *last = NULL;
 522     for (; i < _max-1; ++i) {
 523       Node *next = _in[i+1];
 524       if (next == NULL) break;
 525       last = next;
 526     }
 527     _in[gap] = last; // Move last slot to empty one.
 528     _in[i] = NULL;   // NULL out last slot.
 529   }
 530 
 531 public:
 532   // Globally replace this node by a given new node, updating all uses.
 533   void replace_by(Node* new_node);
 534   // Globally replace this node by a given new node, updating all uses
 535   // and cutting input edges of old node.
 536   void subsume_by(Node* new_node, Compile* c) {
 537     replace_by(new_node);
 538     disconnect_inputs(c);
 539   }
 540   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 541   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 542   // Find the one non-null required input.  RegionNode only
 543   Node *nonnull_req() const;
 544   // Add or remove precedence edges
 545   void add_prec( Node *n );
 546   void rm_prec( uint i );
 547 
 548   // Note: prec(i) will not necessarily point to n if edge already exists.
 549   void set_prec( uint i, Node *n ) {
 550     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 551     assert(is_not_dead(n), "can not use dead node");
 552     assert(i >= _cnt, "not a precedence edge");
 553     // Avoid spec violation: duplicated prec edge.
 554     if (_in[i] == n) return;
 555     if (n == NULL || find_prec_edge(n) != -1) {
 556       rm_prec(i);
 557       return;
 558     }
 559     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 560     _in[i] = n;
 561     n->add_out((Node *)this);
 562   }
 563 
 564   // Set this node's index, used by cisc_version to replace current node
 565   void set_idx(uint new_idx) {
 566     const node_idx_t* ref = &_idx;
 567     *(node_idx_t*)ref = new_idx;
 568   }
 569   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 570   void swap_edges(uint i1, uint i2) {
 571     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 572     // Def-Use info is unchanged
 573     Node* n1 = in(i1);
 574     Node* n2 = in(i2);
 575     _in[i1] = n2;
 576     _in[i2] = n1;
 577     // If this node is in the hash table, make sure it doesn't need a rehash.
 578     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 579   }
 580 
 581   // Iterators over input Nodes for a Node X are written as:
 582   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 583   // NOTE: Required edges can contain embedded NULL pointers.
 584 
 585 //----------------- Other Node Properties
 586 
 587   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 588   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 589   //
 590   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 591   // the type of the node the ID represents; another subset of an ID's bits are reserved
 592   // for the superclasses of the node represented by the ID.
 593   //
 594   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 595   // returns false. A.is_A() returns true.
 596   //
 597   // If two classes, A and B, have the same superclass, a different bit of A's class id
 598   // is reserved for A's type than for B's type. That bit is specified by the third
 599   // parameter in the macro DEFINE_CLASS_ID.
 600   //
 601   // By convention, classes with deeper hierarchy are declared first. Moreover,
 602   // classes with the same hierarchy depth are sorted by usage frequency.
 603   //
 604   // The query method masks the bits to cut off bits of subclasses and then compares
 605   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 606   //
 607   //  Class_MachCall=30, ClassMask_MachCall=31
 608   // 12               8               4               0
 609   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 610   //                                  |   |   |   |
 611   //                                  |   |   |   Bit_Mach=2
 612   //                                  |   |   Bit_MachReturn=4
 613   //                                  |   Bit_MachSafePoint=8
 614   //                                  Bit_MachCall=16
 615   //
 616   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 617   // 12               8               4               0
 618   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 619   //                              |   |   |
 620   //                              |   |   Bit_Region=8
 621   //                              |   Bit_Loop=16
 622   //                              Bit_CountedLoop=32
 623 
 624   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 625   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 626   Class_##cl = Class_##supcl + Bit_##cl , \
 627   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 628 
 629   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 630   // so that its values fit into 32 bits.
 631   enum NodeClasses {
 632     Bit_Node   = 0x00000000,
 633     Class_Node = 0x00000000,
 634     ClassMask_Node = 0xFFFFFFFF,
 635 
 636     DEFINE_CLASS_ID(Multi, Node, 0)
 637       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 638         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 639           DEFINE_CLASS_ID(CallJava,         Call, 0)
 640             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 641             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 642           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 643             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 644               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 645           DEFINE_CLASS_ID(Allocate,         Call, 2)
 646             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 647           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 648             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 649             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 650           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 651           DEFINE_CLASS_ID(CallNative,       Call, 5)
 652       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 653         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 654           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 655           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 656         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 657           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 658             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 659             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 660           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 661           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 662         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 663       DEFINE_CLASS_ID(Start,       Multi, 2)
 664       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 665         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 666         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 667 
 668     DEFINE_CLASS_ID(Mach,  Node, 1)
 669       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 670         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 671           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 672             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 673               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 674               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 675             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 676               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 677             DEFINE_CLASS_ID(MachCallNative,       MachCall, 2)
 678       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 679         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 680         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 681         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 682       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 683       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 684       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 685       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 686         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 687       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 688       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 689 
 690     DEFINE_CLASS_ID(Type,  Node, 2)
 691       DEFINE_CLASS_ID(Phi,   Type, 0)
 692       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 693         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 694         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 695         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 696         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 697         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 698         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 699       DEFINE_CLASS_ID(CMove, Type, 3)
 700       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 701       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 702         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 703         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 704       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 705         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 706         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 707       DEFINE_CLASS_ID(Vector, Type, 7)
 708         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 709 
 710     DEFINE_CLASS_ID(Proj,  Node, 3)
 711       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 712       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 713       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 714         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 715         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 716       DEFINE_CLASS_ID(Parm,      Proj, 4)
 717       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 718 
 719     DEFINE_CLASS_ID(Mem, Node, 4)
 720       DEFINE_CLASS_ID(Load, Mem, 0)
 721         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 722           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 723           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 1)
 724       DEFINE_CLASS_ID(Store, Mem, 1)
 725         DEFINE_CLASS_ID(StoreVector, Store, 0)
 726           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 727           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 1)
 728       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 729         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 730           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 731         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 732 
 733     DEFINE_CLASS_ID(Region, Node, 5)
 734       DEFINE_CLASS_ID(Loop, Region, 0)
 735         DEFINE_CLASS_ID(Root,                Loop, 0)
 736         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 737           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 738           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 739         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 740 
 741     DEFINE_CLASS_ID(Sub,   Node, 6)
 742       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 743         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 744         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 745         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 746 
 747     DEFINE_CLASS_ID(MergeMem, Node, 7)
 748     DEFINE_CLASS_ID(Bool,     Node, 8)
 749     DEFINE_CLASS_ID(AddP,     Node, 9)
 750     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 751     DEFINE_CLASS_ID(Add,      Node, 11)
 752     DEFINE_CLASS_ID(Mul,      Node, 12)
 753     DEFINE_CLASS_ID(ClearArray, Node, 14)
 754     DEFINE_CLASS_ID(Halt,     Node, 15)
 755     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 756     DEFINE_CLASS_ID(Move,     Node, 17)
 757 
 758     _max_classes  = ClassMask_Move
 759   };
 760   #undef DEFINE_CLASS_ID
 761 
 762   // Flags are sorted by usage frequency.
 763   enum NodeFlags {
 764     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 765     Flag_rematerialize               = 1 << 1,
 766     Flag_needs_anti_dependence_check = 1 << 2,
 767     Flag_is_macro                    = 1 << 3,
 768     Flag_is_Con                      = 1 << 4,
 769     Flag_is_cisc_alternate           = 1 << 5,
 770     Flag_is_dead_loop_safe           = 1 << 6,
 771     Flag_may_be_short_branch         = 1 << 7,
 772     Flag_avoid_back_to_back_before   = 1 << 8,
 773     Flag_avoid_back_to_back_after    = 1 << 9,
 774     Flag_has_call                    = 1 << 10,
 775     Flag_is_reduction                = 1 << 11,
 776     Flag_is_scheduled                = 1 << 12,
 777     Flag_has_vector_mask_set         = 1 << 13,
 778     Flag_is_expensive                = 1 << 14,
 779     Flag_for_post_loop_opts_igvn     = 1 << 15,
 780     _last_flag                       = Flag_for_post_loop_opts_igvn
 781   };
 782 
 783   class PD;
 784 
 785 private:
 786   juint _class_id;
 787   juint _flags;
 788 
 789   static juint max_flags();
 790 
 791 protected:
 792   // These methods should be called from constructors only.
 793   void init_class_id(juint c) {
 794     _class_id = c; // cast out const
 795   }
 796   void init_flags(uint fl) {
 797     assert(fl <= max_flags(), "invalid node flag");
 798     _flags |= fl;
 799   }
 800   void clear_flag(uint fl) {
 801     assert(fl <= max_flags(), "invalid node flag");
 802     _flags &= ~fl;
 803   }
 804 
 805 public:
 806   const juint class_id() const { return _class_id; }
 807 
 808   const juint flags() const { return _flags; }
 809 
 810   void add_flag(juint fl) { init_flags(fl); }
 811 
 812   void remove_flag(juint fl) { clear_flag(fl); }
 813 
 814   // Return a dense integer opcode number
 815   virtual int Opcode() const;
 816 
 817   // Virtual inherited Node size
 818   virtual uint size_of() const;
 819 
 820   // Other interesting Node properties
 821   #define DEFINE_CLASS_QUERY(type)                           \
 822   bool is_##type() const {                                   \
 823     return ((_class_id & ClassMask_##type) == Class_##type); \
 824   }                                                          \
 825   type##Node *as_##type() const {                            \
 826     assert(is_##type(), "invalid node class: %s", Name()); \
 827     return (type##Node*)this;                                \
 828   }                                                          \
 829   type##Node* isa_##type() const {                           \
 830     return (is_##type()) ? as_##type() : NULL;               \
 831   }
 832 
 833   DEFINE_CLASS_QUERY(AbstractLock)
 834   DEFINE_CLASS_QUERY(Add)
 835   DEFINE_CLASS_QUERY(AddP)
 836   DEFINE_CLASS_QUERY(Allocate)
 837   DEFINE_CLASS_QUERY(AllocateArray)
 838   DEFINE_CLASS_QUERY(ArrayCopy)
 839   DEFINE_CLASS_QUERY(BaseCountedLoop)
 840   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 841   DEFINE_CLASS_QUERY(Bool)
 842   DEFINE_CLASS_QUERY(BoxLock)
 843   DEFINE_CLASS_QUERY(Call)
 844   DEFINE_CLASS_QUERY(CallNative)
 845   DEFINE_CLASS_QUERY(CallDynamicJava)
 846   DEFINE_CLASS_QUERY(CallJava)
 847   DEFINE_CLASS_QUERY(CallLeaf)
 848   DEFINE_CLASS_QUERY(CallLeafNoFP)
 849   DEFINE_CLASS_QUERY(CallRuntime)
 850   DEFINE_CLASS_QUERY(CallStaticJava)
 851   DEFINE_CLASS_QUERY(Catch)
 852   DEFINE_CLASS_QUERY(CatchProj)
 853   DEFINE_CLASS_QUERY(CheckCastPP)
 854   DEFINE_CLASS_QUERY(CastII)
 855   DEFINE_CLASS_QUERY(CastLL)
 856   DEFINE_CLASS_QUERY(ConstraintCast)
 857   DEFINE_CLASS_QUERY(ClearArray)
 858   DEFINE_CLASS_QUERY(CMove)
 859   DEFINE_CLASS_QUERY(Cmp)
 860   DEFINE_CLASS_QUERY(CountedLoop)
 861   DEFINE_CLASS_QUERY(CountedLoopEnd)
 862   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 863   DEFINE_CLASS_QUERY(DecodeN)
 864   DEFINE_CLASS_QUERY(DecodeNKlass)
 865   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 866   DEFINE_CLASS_QUERY(EncodeP)
 867   DEFINE_CLASS_QUERY(EncodePKlass)
 868   DEFINE_CLASS_QUERY(FastLock)
 869   DEFINE_CLASS_QUERY(FastUnlock)
 870   DEFINE_CLASS_QUERY(Halt)
 871   DEFINE_CLASS_QUERY(If)
 872   DEFINE_CLASS_QUERY(RangeCheck)
 873   DEFINE_CLASS_QUERY(IfProj)
 874   DEFINE_CLASS_QUERY(IfFalse)
 875   DEFINE_CLASS_QUERY(IfTrue)
 876   DEFINE_CLASS_QUERY(Initialize)
 877   DEFINE_CLASS_QUERY(Jump)
 878   DEFINE_CLASS_QUERY(JumpProj)
 879   DEFINE_CLASS_QUERY(LongCountedLoop)
 880   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 881   DEFINE_CLASS_QUERY(Load)
 882   DEFINE_CLASS_QUERY(LoadStore)
 883   DEFINE_CLASS_QUERY(LoadStoreConditional)
 884   DEFINE_CLASS_QUERY(Lock)
 885   DEFINE_CLASS_QUERY(Loop)
 886   DEFINE_CLASS_QUERY(Mach)
 887   DEFINE_CLASS_QUERY(MachBranch)
 888   DEFINE_CLASS_QUERY(MachCall)
 889   DEFINE_CLASS_QUERY(MachCallNative)
 890   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 891   DEFINE_CLASS_QUERY(MachCallJava)
 892   DEFINE_CLASS_QUERY(MachCallLeaf)
 893   DEFINE_CLASS_QUERY(MachCallRuntime)
 894   DEFINE_CLASS_QUERY(MachCallStaticJava)
 895   DEFINE_CLASS_QUERY(MachConstantBase)
 896   DEFINE_CLASS_QUERY(MachConstant)
 897   DEFINE_CLASS_QUERY(MachGoto)
 898   DEFINE_CLASS_QUERY(MachIf)
 899   DEFINE_CLASS_QUERY(MachJump)
 900   DEFINE_CLASS_QUERY(MachNullCheck)
 901   DEFINE_CLASS_QUERY(MachProj)
 902   DEFINE_CLASS_QUERY(MachReturn)
 903   DEFINE_CLASS_QUERY(MachSafePoint)
 904   DEFINE_CLASS_QUERY(MachSpillCopy)
 905   DEFINE_CLASS_QUERY(MachTemp)
 906   DEFINE_CLASS_QUERY(MachMemBar)
 907   DEFINE_CLASS_QUERY(MachMerge)
 908   DEFINE_CLASS_QUERY(Mem)
 909   DEFINE_CLASS_QUERY(MemBar)
 910   DEFINE_CLASS_QUERY(MemBarStoreStore)
 911   DEFINE_CLASS_QUERY(MergeMem)
 912   DEFINE_CLASS_QUERY(Move)
 913   DEFINE_CLASS_QUERY(Mul)
 914   DEFINE_CLASS_QUERY(Multi)
 915   DEFINE_CLASS_QUERY(MultiBranch)
 916   DEFINE_CLASS_QUERY(Opaque1)
 917   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 918   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 919   DEFINE_CLASS_QUERY(Parm)
 920   DEFINE_CLASS_QUERY(PCTable)
 921   DEFINE_CLASS_QUERY(Phi)
 922   DEFINE_CLASS_QUERY(Proj)
 923   DEFINE_CLASS_QUERY(Region)
 924   DEFINE_CLASS_QUERY(Root)
 925   DEFINE_CLASS_QUERY(SafePoint)
 926   DEFINE_CLASS_QUERY(SafePointScalarObject)
 927   DEFINE_CLASS_QUERY(Start)
 928   DEFINE_CLASS_QUERY(Store)
 929   DEFINE_CLASS_QUERY(Sub)
 930   DEFINE_CLASS_QUERY(SubTypeCheck)
 931   DEFINE_CLASS_QUERY(Type)
 932   DEFINE_CLASS_QUERY(Vector)
 933   DEFINE_CLASS_QUERY(LoadVector)
 934   DEFINE_CLASS_QUERY(LoadVectorGather)
 935   DEFINE_CLASS_QUERY(StoreVector)
 936   DEFINE_CLASS_QUERY(StoreVectorScatter)
 937   DEFINE_CLASS_QUERY(VectorMaskCmp)
 938   DEFINE_CLASS_QUERY(Unlock)
 939 
 940   #undef DEFINE_CLASS_QUERY
 941 
 942   // duplicate of is_MachSpillCopy()
 943   bool is_SpillCopy () const {
 944     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 945   }
 946 
 947   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 948   // The data node which is safe to leave in dead loop during IGVN optimization.
 949   bool is_dead_loop_safe() const;
 950 
 951   // is_Copy() returns copied edge index (0 or 1)
 952   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 953 
 954   virtual bool is_CFG() const { return false; }
 955 
 956   // If this node is control-dependent on a test, can it be
 957   // rerouted to a dominating equivalent test?  This is usually
 958   // true of non-CFG nodes, but can be false for operations which
 959   // depend for their correct sequencing on more than one test.
 960   // (In that case, hoisting to a dominating test may silently
 961   // skip some other important test.)
 962   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 963 
 964   // When building basic blocks, I need to have a notion of block beginning
 965   // Nodes, next block selector Nodes (block enders), and next block
 966   // projections.  These calls need to work on their machine equivalents.  The
 967   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 968   bool is_block_start() const {
 969     if ( is_Region() )
 970       return this == (const Node*)in(0);
 971     else
 972       return is_Start();
 973   }
 974 
 975   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 976   // Goto and Return.  This call also returns the block ending Node.
 977   virtual const Node *is_block_proj() const;
 978 
 979   // The node is a "macro" node which needs to be expanded before matching
 980   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 981   // The node is expensive: the best control is set during loop opts
 982   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 983 
 984   // An arithmetic node which accumulates a data in a loop.
 985   // It must have the loop's phi as input and provide a def to the phi.
 986   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 987 
 988   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
 989   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
 990 
 991   // Used in lcm to mark nodes that have scheduled
 992   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
 993 
 994   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
 995 
 996 //----------------- Optimization
 997 
 998   // Get the worst-case Type output for this Node.
 999   virtual const class Type *bottom_type() const;
1000 
1001   // If we find a better type for a node, try to record it permanently.
1002   // Return true if this node actually changed.
1003   // Be sure to do the hash_delete game in the "rehash" variant.
1004   void raise_bottom_type(const Type* new_type);
1005 
1006   // Get the address type with which this node uses and/or defs memory,
1007   // or NULL if none.  The address type is conservatively wide.
1008   // Returns non-null for calls, membars, loads, stores, etc.
1009   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1010   virtual const class TypePtr *adr_type() const { return NULL; }
1011 
1012   // Return an existing node which computes the same function as this node.
1013   // The optimistic combined algorithm requires this to return a Node which
1014   // is a small number of steps away (e.g., one of my inputs).
1015   virtual Node* Identity(PhaseGVN* phase);
1016 
1017   // Return the set of values this Node can take on at runtime.
1018   virtual const Type* Value(PhaseGVN* phase) const;
1019 
1020   // Return a node which is more "ideal" than the current node.
1021   // The invariants on this call are subtle.  If in doubt, read the
1022   // treatise in node.cpp above the default implemention AND TEST WITH
1023   // +VerifyIterativeGVN!
1024   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1025 
1026   // Some nodes have specific Ideal subgraph transformations only if they are
1027   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1028   // for the transformations to happen.
1029   bool has_special_unique_user() const;
1030 
1031   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1032   Node* find_exact_control(Node* ctrl);
1033 
1034   // Check if 'this' node dominates or equal to 'sub'.
1035   bool dominates(Node* sub, Node_List &nlist);
1036 
1037 protected:
1038   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1039 public:
1040 
1041   // See if there is valid pipeline info
1042   static  const Pipeline *pipeline_class();
1043   virtual const Pipeline *pipeline() const;
1044 
1045   // Compute the latency from the def to this instruction of the ith input node
1046   uint latency(uint i);
1047 
1048   // Hash & compare functions, for pessimistic value numbering
1049 
1050   // If the hash function returns the special sentinel value NO_HASH,
1051   // the node is guaranteed never to compare equal to any other node.
1052   // If we accidentally generate a hash with value NO_HASH the node
1053   // won't go into the table and we'll lose a little optimization.
1054   static const uint NO_HASH = 0;
1055   virtual uint hash() const;
1056   virtual bool cmp( const Node &n ) const;
1057 
1058   // Operation appears to be iteratively computed (such as an induction variable)
1059   // It is possible for this operation to return false for a loop-varying
1060   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1061   bool is_iteratively_computed();
1062 
1063   // Determine if a node is a counted loop induction variable.
1064   // NOTE: The method is defined in "loopnode.cpp".
1065   bool is_cloop_ind_var() const;
1066 
1067   // Return a node with opcode "opc" and same inputs as "this" if one can
1068   // be found; Otherwise return NULL;
1069   Node* find_similar(int opc);
1070 
1071   // Return the unique control out if only one. Null if none or more than one.
1072   Node* unique_ctrl_out() const;
1073 
1074   // Set control or add control as precedence edge
1075   void ensure_control_or_add_prec(Node* c);
1076 
1077 //----------------- Code Generation
1078 
1079   // Ideal register class for Matching.  Zero means unmatched instruction
1080   // (these are cloned instead of converted to machine nodes).
1081   virtual uint ideal_reg() const;
1082 
1083   static const uint NotAMachineReg;   // must be > max. machine register
1084 
1085   // Do we Match on this edge index or not?  Generally false for Control
1086   // and true for everything else.  Weird for calls & returns.
1087   virtual uint match_edge(uint idx) const;
1088 
1089   // Register class output is returned in
1090   virtual const RegMask &out_RegMask() const;
1091   // Register class input is expected in
1092   virtual const RegMask &in_RegMask(uint) const;
1093   // Should we clone rather than spill this instruction?
1094   bool rematerialize() const;
1095 
1096   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1097   virtual JVMState* jvms() const;
1098 
1099   // Print as assembly
1100   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1101   // Emit bytes starting at parameter 'ptr'
1102   // Bump 'ptr' by the number of output bytes
1103   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1104   // Size of instruction in bytes
1105   virtual uint size(PhaseRegAlloc *ra_) const;
1106 
1107   // Convenience function to extract an integer constant from a node.
1108   // If it is not an integer constant (either Con, CastII, or Mach),
1109   // return value_if_unknown.
1110   jint find_int_con(jint value_if_unknown) const {
1111     const TypeInt* t = find_int_type();
1112     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1113   }
1114   // Return the constant, knowing it is an integer constant already
1115   jint get_int() const {
1116     const TypeInt* t = find_int_type();
1117     guarantee(t != NULL, "must be con");
1118     return t->get_con();
1119   }
1120   // Here's where the work is done.  Can produce non-constant int types too.
1121   const TypeInt* find_int_type() const;
1122   const TypeInteger* find_integer_type(BasicType bt) const;
1123 
1124   // Same thing for long (and intptr_t, via type.hpp):
1125   jlong get_long() const {
1126     const TypeLong* t = find_long_type();
1127     guarantee(t != NULL, "must be con");
1128     return t->get_con();
1129   }
1130   jlong find_long_con(jint value_if_unknown) const {
1131     const TypeLong* t = find_long_type();
1132     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1133   }
1134   const TypeLong* find_long_type() const;
1135 
1136   jlong get_integer_as_long(BasicType bt) const {
1137     const TypeInteger* t = find_integer_type(bt);
1138     guarantee(t != NULL, "must be con");
1139     return t->get_con_as_long(bt);
1140   }
1141   const TypePtr* get_ptr_type() const;
1142 
1143   // These guys are called by code generated by ADLC:
1144   intptr_t get_ptr() const;
1145   intptr_t get_narrowcon() const;
1146   jdouble getd() const;
1147   jfloat getf() const;
1148 
1149   // Nodes which are pinned into basic blocks
1150   virtual bool pinned() const { return false; }
1151 
1152   // Nodes which use memory without consuming it, hence need antidependences
1153   // More specifically, needs_anti_dependence_check returns true iff the node
1154   // (a) does a load, and (b) does not perform a store (except perhaps to a
1155   // stack slot or some other unaliased location).
1156   bool needs_anti_dependence_check() const;
1157 
1158   // Return which operand this instruction may cisc-spill. In other words,
1159   // return operand position that can convert from reg to memory access
1160   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1161   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1162 
1163   // Whether this is a memory-writing machine node.
1164   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1165 
1166 //----------------- Printing, etc
1167 #ifndef PRODUCT
1168  private:
1169   int _indent;
1170 
1171  public:
1172   void set_indent(int indent) { _indent = indent; }
1173 
1174  private:
1175   static bool add_to_worklist(Node* n, Node_List* worklist, Arena* old_arena, VectorSet* old_space, VectorSet* new_space);
1176 public:
1177   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1178   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1179   void dump() const { dump("\n"); }  // Print this node.
1180   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1181   void dump(int depth) const;        // Print this node, recursively to depth d
1182   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1183   void dump_comp() const;            // Print this node in compact representation.
1184   // Print this node in compact representation.
1185   void dump_comp(const char* suffix, outputStream *st = tty) const;
1186   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1187   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1188   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1189   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1190   // Print compact per-node info
1191   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1192   void dump_related() const;             // Print related nodes (depends on node at hand).
1193   // Print related nodes up to given depths for input and output nodes.
1194   void dump_related(uint d_in, uint d_out) const;
1195   void dump_related_compact() const;     // Print related nodes in compact representation.
1196   // Collect related nodes.
1197   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1198   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1199   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1200 
1201   // Node collectors, to be used in implementations of Node::rel().
1202   // Collect the entire data input graph. Include control inputs if requested.
1203   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1204   // Collect the entire control input graph. Include data inputs if requested.
1205   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1206   // Collect the entire output graph until hitting and including control nodes.
1207   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1208 
1209   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1210   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1211 
1212   // This call defines a class-unique string used to identify class instances
1213   virtual const char *Name() const;
1214 
1215   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1216   // RegMask Print Functions
1217   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1218   void dump_out_regmask() { out_RegMask().dump(); }
1219   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1220   void fast_dump() const {
1221     tty->print("%4d: %-17s", _idx, Name());
1222     for (uint i = 0; i < len(); i++)
1223       if (in(i))
1224         tty->print(" %4d", in(i)->_idx);
1225       else
1226         tty->print(" NULL");
1227     tty->print("\n");
1228   }
1229 #endif
1230 #ifdef ASSERT
1231   void verify_construction();
1232   bool verify_jvms(const JVMState* jvms) const;
1233   int  _debug_idx;                     // Unique value assigned to every node.
1234   int   debug_idx() const              { return _debug_idx; }
1235   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1236 
1237   Node* _debug_orig;                   // Original version of this, if any.
1238   Node*  debug_orig() const            { return _debug_orig; }
1239   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1240   void   dump_orig(outputStream *st, bool print_key = true) const;
1241 
1242   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1243   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1244   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1245 
1246   static void init_NodeProperty();
1247 
1248   #if OPTO_DU_ITERATOR_ASSERT
1249   const Node* _last_del;               // The last deleted node.
1250   uint        _del_tick;               // Bumped when a deletion happens..
1251   #endif
1252 #endif
1253 public:
1254   virtual bool operates_on(BasicType bt, bool signed_int) const {
1255     assert(bt == T_INT || bt == T_LONG, "unsupported");
1256     Unimplemented();
1257     return false;
1258   }
1259 };
1260 
1261 inline bool not_a_node(const Node* n) {
1262   if (n == NULL)                   return true;
1263   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1264   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1265   return false;
1266 }
1267 
1268 //-----------------------------------------------------------------------------
1269 // Iterators over DU info, and associated Node functions.
1270 
1271 #if OPTO_DU_ITERATOR_ASSERT
1272 
1273 // Common code for assertion checking on DU iterators.
1274 class DUIterator_Common {
1275 #ifdef ASSERT
1276  protected:
1277   bool         _vdui;               // cached value of VerifyDUIterators
1278   const Node*  _node;               // the node containing the _out array
1279   uint         _outcnt;             // cached node->_outcnt
1280   uint         _del_tick;           // cached node->_del_tick
1281   Node*        _last;               // last value produced by the iterator
1282 
1283   void sample(const Node* node);    // used by c'tor to set up for verifies
1284   void verify(const Node* node, bool at_end_ok = false);
1285   void verify_resync();
1286   void reset(const DUIterator_Common& that);
1287 
1288 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1289   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1290 #else
1291   #define I_VDUI_ONLY(i,x) { }
1292 #endif //ASSERT
1293 };
1294 
1295 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1296 
1297 // Default DU iterator.  Allows appends onto the out array.
1298 // Allows deletion from the out array only at the current point.
1299 // Usage:
1300 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1301 //    Node* y = x->out(i);
1302 //    ...
1303 //  }
1304 // Compiles in product mode to a unsigned integer index, which indexes
1305 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1306 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1307 // before continuing the loop.  You must delete only the last-produced
1308 // edge.  You must delete only a single copy of the last-produced edge,
1309 // or else you must delete all copies at once (the first time the edge
1310 // is produced by the iterator).
1311 class DUIterator : public DUIterator_Common {
1312   friend class Node;
1313 
1314   // This is the index which provides the product-mode behavior.
1315   // Whatever the product-mode version of the system does to the
1316   // DUI index is done to this index.  All other fields in
1317   // this class are used only for assertion checking.
1318   uint         _idx;
1319 
1320   #ifdef ASSERT
1321   uint         _refresh_tick;    // Records the refresh activity.
1322 
1323   void sample(const Node* node); // Initialize _refresh_tick etc.
1324   void verify(const Node* node, bool at_end_ok = false);
1325   void verify_increment();       // Verify an increment operation.
1326   void verify_resync();          // Verify that we can back up over a deletion.
1327   void verify_finish();          // Verify that the loop terminated properly.
1328   void refresh();                // Resample verification info.
1329   void reset(const DUIterator& that);  // Resample after assignment.
1330   #endif
1331 
1332   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1333     { _idx = 0;                         debug_only(sample(node)); }
1334 
1335  public:
1336   // initialize to garbage; clear _vdui to disable asserts
1337   DUIterator()
1338     { /*initialize to garbage*/         debug_only(_vdui = false); }
1339 
1340   DUIterator(const DUIterator& that)
1341     { _idx = that._idx;                 debug_only(_vdui = false; reset(that)); }
1342 
1343   void operator++(int dummy_to_specify_postfix_op)
1344     { _idx++;                           VDUI_ONLY(verify_increment()); }
1345 
1346   void operator--()
1347     { VDUI_ONLY(verify_resync());       --_idx; }
1348 
1349   ~DUIterator()
1350     { VDUI_ONLY(verify_finish()); }
1351 
1352   void operator=(const DUIterator& that)
1353     { _idx = that._idx;                 debug_only(reset(that)); }
1354 };
1355 
1356 DUIterator Node::outs() const
1357   { return DUIterator(this, 0); }
1358 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1359   { I_VDUI_ONLY(i, i.refresh());        return i; }
1360 bool Node::has_out(DUIterator& i) const
1361   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1362 Node*    Node::out(DUIterator& i) const
1363   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1364 
1365 
1366 // Faster DU iterator.  Disallows insertions into the out array.
1367 // Allows deletion from the out array only at the current point.
1368 // Usage:
1369 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1370 //    Node* y = x->fast_out(i);
1371 //    ...
1372 //  }
1373 // Compiles in product mode to raw Node** pointer arithmetic, with
1374 // no reloading of pointers from the original node x.  If you delete,
1375 // you must perform "--i; --imax" just before continuing the loop.
1376 // If you delete multiple copies of the same edge, you must decrement
1377 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1378 class DUIterator_Fast : public DUIterator_Common {
1379   friend class Node;
1380   friend class DUIterator_Last;
1381 
1382   // This is the pointer which provides the product-mode behavior.
1383   // Whatever the product-mode version of the system does to the
1384   // DUI pointer is done to this pointer.  All other fields in
1385   // this class are used only for assertion checking.
1386   Node**       _outp;
1387 
1388   #ifdef ASSERT
1389   void verify(const Node* node, bool at_end_ok = false);
1390   void verify_limit();
1391   void verify_resync();
1392   void verify_relimit(uint n);
1393   void reset(const DUIterator_Fast& that);
1394   #endif
1395 
1396   // Note:  offset must be signed, since -1 is sometimes passed
1397   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1398     { _outp = node->_out + offset;      debug_only(sample(node)); }
1399 
1400  public:
1401   // initialize to garbage; clear _vdui to disable asserts
1402   DUIterator_Fast()
1403     { /*initialize to garbage*/         debug_only(_vdui = false); }
1404 
1405   DUIterator_Fast(const DUIterator_Fast& that)
1406     { _outp = that._outp;               debug_only(_vdui = false; reset(that)); }
1407 
1408   void operator++(int dummy_to_specify_postfix_op)
1409     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1410 
1411   void operator--()
1412     { VDUI_ONLY(verify_resync());       --_outp; }
1413 
1414   void operator-=(uint n)   // applied to the limit only
1415     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1416 
1417   bool operator<(DUIterator_Fast& limit) {
1418     I_VDUI_ONLY(*this, this->verify(_node, true));
1419     I_VDUI_ONLY(limit, limit.verify_limit());
1420     return _outp < limit._outp;
1421   }
1422 
1423   void operator=(const DUIterator_Fast& that)
1424     { _outp = that._outp;               debug_only(reset(that)); }
1425 };
1426 
1427 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1428   // Assign a limit pointer to the reference argument:
1429   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1430   // Return the base pointer:
1431   return DUIterator_Fast(this, 0);
1432 }
1433 Node* Node::fast_out(DUIterator_Fast& i) const {
1434   I_VDUI_ONLY(i, i.verify(this));
1435   return debug_only(i._last=) *i._outp;
1436 }
1437 
1438 
1439 // Faster DU iterator.  Requires each successive edge to be removed.
1440 // Does not allow insertion of any edges.
1441 // Usage:
1442 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1443 //    Node* y = x->last_out(i);
1444 //    ...
1445 //  }
1446 // Compiles in product mode to raw Node** pointer arithmetic, with
1447 // no reloading of pointers from the original node x.
1448 class DUIterator_Last : private DUIterator_Fast {
1449   friend class Node;
1450 
1451   #ifdef ASSERT
1452   void verify(const Node* node, bool at_end_ok = false);
1453   void verify_limit();
1454   void verify_step(uint num_edges);
1455   #endif
1456 
1457   // Note:  offset must be signed, since -1 is sometimes passed
1458   DUIterator_Last(const Node* node, ptrdiff_t offset)
1459     : DUIterator_Fast(node, offset) { }
1460 
1461   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1462   void operator<(int)                              {} // do not use
1463 
1464  public:
1465   DUIterator_Last() { }
1466   // initialize to garbage
1467 
1468   DUIterator_Last(const DUIterator_Last& that) = default;
1469 
1470   void operator--()
1471     { _outp--;              VDUI_ONLY(verify_step(1));  }
1472 
1473   void operator-=(uint n)
1474     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1475 
1476   bool operator>=(DUIterator_Last& limit) {
1477     I_VDUI_ONLY(*this, this->verify(_node, true));
1478     I_VDUI_ONLY(limit, limit.verify_limit());
1479     return _outp >= limit._outp;
1480   }
1481 
1482   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1483 };
1484 
1485 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1486   // Assign a limit pointer to the reference argument:
1487   imin = DUIterator_Last(this, 0);
1488   // Return the initial pointer:
1489   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1490 }
1491 Node* Node::last_out(DUIterator_Last& i) const {
1492   I_VDUI_ONLY(i, i.verify(this));
1493   return debug_only(i._last=) *i._outp;
1494 }
1495 
1496 #endif //OPTO_DU_ITERATOR_ASSERT
1497 
1498 #undef I_VDUI_ONLY
1499 #undef VDUI_ONLY
1500 
1501 // An Iterator that truly follows the iterator pattern.  Doesn't
1502 // support deletion but could be made to.
1503 //
1504 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1505 //     Node* m = i.get();
1506 //
1507 class SimpleDUIterator : public StackObj {
1508  private:
1509   Node* node;
1510   DUIterator_Fast i;
1511   DUIterator_Fast imax;
1512  public:
1513   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1514   bool has_next() { return i < imax; }
1515   void next() { i++; }
1516   Node* get() { return node->fast_out(i); }
1517 };
1518 
1519 
1520 //-----------------------------------------------------------------------------
1521 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1522 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1523 // Note that the constructor just zeros things, and since I use Arena
1524 // allocation I do not need a destructor to reclaim storage.
1525 class Node_Array : public ResourceObj {
1526   friend class VMStructs;
1527 protected:
1528   Arena* _a;                    // Arena to allocate in
1529   uint   _max;
1530   Node** _nodes;
1531   void   grow( uint i );        // Grow array node to fit
1532 public:
1533   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1534     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1535     clear();
1536   }
1537 
1538   Node_Array(Node_Array* na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1539   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1540   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1541   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1542   Node** adr() { return _nodes; }
1543   // Extend the mapping: index i maps to Node *n.
1544   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1545   void insert( uint i, Node *n );
1546   void remove( uint i );        // Remove, preserving order
1547   // Clear all entries in _nodes to NULL but keep storage
1548   void clear() {
1549     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1550   }
1551 
1552   uint Size() const { return _max; }
1553   void dump() const;
1554 };
1555 
1556 class Node_List : public Node_Array {
1557   friend class VMStructs;
1558   uint _cnt;
1559 public:
1560   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1561   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1562   bool contains(const Node* n) const {
1563     for (uint e = 0; e < size(); e++) {
1564       if (at(e) == n) return true;
1565     }
1566     return false;
1567   }
1568   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1569   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1570   void push( Node *b ) { map(_cnt++,b); }
1571   void yank( Node *n );         // Find and remove
1572   Node *pop() { return _nodes[--_cnt]; }
1573   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1574   void copy(const Node_List& from) {
1575     if (from._max > _max) {
1576       grow(from._max);
1577     }
1578     _cnt = from._cnt;
1579     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1580   }
1581 
1582   uint size() const { return _cnt; }
1583   void dump() const;
1584   void dump_simple() const;
1585 };
1586 
1587 //------------------------------Unique_Node_List-------------------------------
1588 class Unique_Node_List : public Node_List {
1589   friend class VMStructs;
1590   VectorSet _in_worklist;
1591   uint _clock_index;            // Index in list where to pop from next
1592 public:
1593   Unique_Node_List() : Node_List(), _clock_index(0) {}
1594   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1595 
1596   void remove( Node *n );
1597   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1598   VectorSet& member_set(){ return _in_worklist; }
1599 
1600   void push(Node* b) {
1601     if( !_in_worklist.test_set(b->_idx) )
1602       Node_List::push(b);
1603   }
1604   Node *pop() {
1605     if( _clock_index >= size() ) _clock_index = 0;
1606     Node *b = at(_clock_index);
1607     map( _clock_index, Node_List::pop());
1608     if (size() != 0) _clock_index++; // Always start from 0
1609     _in_worklist.remove(b->_idx);
1610     return b;
1611   }
1612   Node *remove(uint i) {
1613     Node *b = Node_List::at(i);
1614     _in_worklist.remove(b->_idx);
1615     map(i,Node_List::pop());
1616     return b;
1617   }
1618   void yank(Node *n) {
1619     _in_worklist.remove(n->_idx);
1620     Node_List::yank(n);
1621   }
1622   void  clear() {
1623     _in_worklist.clear();        // Discards storage but grows automatically
1624     Node_List::clear();
1625     _clock_index = 0;
1626   }
1627 
1628   // Used after parsing to remove useless nodes before Iterative GVN
1629   void remove_useless_nodes(VectorSet& useful);
1630 
1631   bool contains(const Node* n) const {
1632     fatal("use faster member() instead");
1633     return false;
1634   }
1635 
1636 #ifndef PRODUCT
1637   void print_set() const { _in_worklist.print(); }
1638 #endif
1639 };
1640 
1641 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1642 inline void Compile::record_for_igvn(Node* n) {
1643   _for_igvn->push(n);
1644 }
1645 
1646 //------------------------------Node_Stack-------------------------------------
1647 class Node_Stack {
1648   friend class VMStructs;
1649 protected:
1650   struct INode {
1651     Node *node; // Processed node
1652     uint  indx; // Index of next node's child
1653   };
1654   INode *_inode_top; // tos, stack grows up
1655   INode *_inode_max; // End of _inodes == _inodes + _max
1656   INode *_inodes;    // Array storage for the stack
1657   Arena *_a;         // Arena to allocate in
1658   void grow();
1659 public:
1660   Node_Stack(int size) {
1661     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1662     _a = Thread::current()->resource_area();
1663     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1664     _inode_max = _inodes + max;
1665     _inode_top = _inodes - 1; // stack is empty
1666   }
1667 
1668   Node_Stack(Arena *a, int size) : _a(a) {
1669     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1670     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1671     _inode_max = _inodes + max;
1672     _inode_top = _inodes - 1; // stack is empty
1673   }
1674 
1675   void pop() {
1676     assert(_inode_top >= _inodes, "node stack underflow");
1677     --_inode_top;
1678   }
1679   void push(Node *n, uint i) {
1680     ++_inode_top;
1681     if (_inode_top >= _inode_max) grow();
1682     INode *top = _inode_top; // optimization
1683     top->node = n;
1684     top->indx = i;
1685   }
1686   Node *node() const {
1687     return _inode_top->node;
1688   }
1689   Node* node_at(uint i) const {
1690     assert(_inodes + i <= _inode_top, "in range");
1691     return _inodes[i].node;
1692   }
1693   uint index() const {
1694     return _inode_top->indx;
1695   }
1696   uint index_at(uint i) const {
1697     assert(_inodes + i <= _inode_top, "in range");
1698     return _inodes[i].indx;
1699   }
1700   void set_node(Node *n) {
1701     _inode_top->node = n;
1702   }
1703   void set_index(uint i) {
1704     _inode_top->indx = i;
1705   }
1706   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1707   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1708   bool is_nonempty() const { return (_inode_top >= _inodes); }
1709   bool is_empty() const { return (_inode_top < _inodes); }
1710   void clear() { _inode_top = _inodes - 1; } // retain storage
1711 
1712   // Node_Stack is used to map nodes.
1713   Node* find(uint idx) const;
1714 };
1715 
1716 
1717 //-----------------------------Node_Notes--------------------------------------
1718 // Debugging or profiling annotations loosely and sparsely associated
1719 // with some nodes.  See Compile::node_notes_at for the accessor.
1720 class Node_Notes {
1721   friend class VMStructs;
1722   JVMState* _jvms;
1723 
1724 public:
1725   Node_Notes(JVMState* jvms = NULL) {
1726     _jvms = jvms;
1727   }
1728 
1729   JVMState* jvms()            { return _jvms; }
1730   void  set_jvms(JVMState* x) {        _jvms = x; }
1731 
1732   // True if there is nothing here.
1733   bool is_clear() {
1734     return (_jvms == NULL);
1735   }
1736 
1737   // Make there be nothing here.
1738   void clear() {
1739     _jvms = NULL;
1740   }
1741 
1742   // Make a new, clean node notes.
1743   static Node_Notes* make(Compile* C) {
1744     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1745     nn->clear();
1746     return nn;
1747   }
1748 
1749   Node_Notes* clone(Compile* C) {
1750     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1751     (*nn) = (*this);
1752     return nn;
1753   }
1754 
1755   // Absorb any information from source.
1756   bool update_from(Node_Notes* source) {
1757     bool changed = false;
1758     if (source != NULL) {
1759       if (source->jvms() != NULL) {
1760         set_jvms(source->jvms());
1761         changed = true;
1762       }
1763     }
1764     return changed;
1765   }
1766 };
1767 
1768 // Inlined accessors for Compile::node_nodes that require the preceding class:
1769 inline Node_Notes*
1770 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1771                            int idx, bool can_grow) {
1772   assert(idx >= 0, "oob");
1773   int block_idx = (idx >> _log2_node_notes_block_size);
1774   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1775   if (grow_by >= 0) {
1776     if (!can_grow) return NULL;
1777     grow_node_notes(arr, grow_by + 1);
1778   }
1779   if (arr == NULL) return NULL;
1780   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1781   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1782 }
1783 
1784 inline bool
1785 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1786   if (value == NULL || value->is_clear())
1787     return false;  // nothing to write => write nothing
1788   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1789   assert(loc != NULL, "");
1790   return loc->update_from(value);
1791 }
1792 
1793 
1794 //------------------------------TypeNode---------------------------------------
1795 // Node with a Type constant.
1796 class TypeNode : public Node {
1797 protected:
1798   virtual uint hash() const;    // Check the type
1799   virtual bool cmp( const Node &n ) const;
1800   virtual uint size_of() const; // Size is bigger
1801   const Type* const _type;
1802 public:
1803   void set_type(const Type* t) {
1804     assert(t != NULL, "sanity");
1805     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1806     *(const Type**)&_type = t;   // cast away const-ness
1807     // If this node is in the hash table, make sure it doesn't need a rehash.
1808     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1809   }
1810   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1811   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1812     init_class_id(Class_Type);
1813   }
1814   virtual const Type* Value(PhaseGVN* phase) const;
1815   virtual const Type *bottom_type() const;
1816   virtual       uint  ideal_reg() const;
1817 #ifndef PRODUCT
1818   virtual void dump_spec(outputStream *st) const;
1819   virtual void dump_compact_spec(outputStream *st) const;
1820 #endif
1821 };
1822 
1823 #endif // SHARE_OPTO_NODE_HPP