1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_NODE_HPP
  26 #define SHARE_VM_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 
  32 // Portions of code courtesy of Clifford Click
  33 
  34 // Optimization - Graph Style
  35 
  36 
  37 class AbstractLockNode;
  38 class AddNode;
  39 class AddPNode;
  40 class AliasInfo;
  41 class AllocateArrayNode;
  42 class AllocateNode;
  43 class ArrayCopyNode;
  44 class Block;
  45 class BoolNode;
  46 class BoxLockNode;
  47 class CMoveNode;
  48 class CallDynamicJavaNode;
  49 class CallJavaNode;
  50 class CallLeafNode;
  51 class CallNode;
  52 class CallRuntimeNode;
  53 class CallStaticJavaNode;
  54 class CatchNode;
  55 class CatchProjNode;
  56 class CheckCastPPNode;
  57 class ClearArrayNode;
  58 class CmpNode;
  59 class CodeBuffer;
  60 class ConstraintCastNode;
  61 class ConNode;
  62 class CountedLoopNode;
  63 class CountedLoopEndNode;
  64 class DecodeNarrowPtrNode;
  65 class DecodeNNode;
  66 class DecodeNKlassNode;
  67 class EncodeNarrowPtrNode;
  68 class EncodePNode;
  69 class EncodePKlassNode;
  70 class FastLockNode;
  71 class FastUnlockNode;
  72 class IfNode;
  73 class IfFalseNode;
  74 class IfTrueNode;
  75 class InitializeNode;
  76 class JVMState;
  77 class JumpNode;
  78 class JumpProjNode;
  79 class LoadNode;
  80 class LoadStoreNode;
  81 class LockNode;
  82 class LoopNode;
  83 class MachBranchNode;
  84 class MachCallDynamicJavaNode;
  85 class MachCallJavaNode;
  86 class MachCallLeafNode;
  87 class MachCallNode;
  88 class MachCallRuntimeNode;
  89 class MachCallStaticJavaNode;
  90 class MachConstantBaseNode;
  91 class MachConstantNode;
  92 class MachGotoNode;
  93 class MachIfNode;
  94 class MachNode;
  95 class MachNullCheckNode;
  96 class MachProjNode;
  97 class MachReturnNode;
  98 class MachSafePointNode;
  99 class MachSpillCopyNode;
 100 class MachTempNode;
 101 class MachMergeNode;
 102 class Matcher;
 103 class MemBarNode;
 104 class MemBarStoreStoreNode;
 105 class MemNode;
 106 class MergeMemNode;
 107 class MulNode;
 108 class MultiNode;
 109 class MultiBranchNode;
 110 class NeverBranchNode;
 111 class Node;
 112 class Node_Array;
 113 class Node_List;
 114 class Node_Stack;
 115 class NullCheckNode;
 116 class OopMap;
 117 class ParmNode;
 118 class PCTableNode;
 119 class PhaseCCP;
 120 class PhaseGVN;
 121 class PhaseIterGVN;
 122 class PhaseRegAlloc;
 123 class PhaseTransform;
 124 class PhaseValues;
 125 class PhiNode;
 126 class Pipeline;
 127 class ProjNode;
 128 class RegMask;
 129 class RegionNode;
 130 class RootNode;
 131 class SafePointNode;
 132 class SafePointScalarObjectNode;
 133 class StartNode;
 134 class State;
 135 class StoreNode;
 136 class SubNode;
 137 class Type;
 138 class TypeNode;
 139 class UnlockNode;
 140 class VectorNode;
 141 class LoadVectorNode;
 142 class StoreVectorNode;
 143 class VectorSet;
 144 typedef void (*NFunc)(Node&,void*);
 145 extern "C" {
 146   typedef int (*C_sort_func_t)(const void *, const void *);
 147 }
 148 
 149 // The type of all node counts and indexes.
 150 // It must hold at least 16 bits, but must also be fast to load and store.
 151 // This type, if less than 32 bits, could limit the number of possible nodes.
 152 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 153 typedef unsigned int node_idx_t;
 154 
 155 
 156 #ifndef OPTO_DU_ITERATOR_ASSERT
 157 #ifdef ASSERT
 158 #define OPTO_DU_ITERATOR_ASSERT 1
 159 #else
 160 #define OPTO_DU_ITERATOR_ASSERT 0
 161 #endif
 162 #endif //OPTO_DU_ITERATOR_ASSERT
 163 
 164 #if OPTO_DU_ITERATOR_ASSERT
 165 class DUIterator;
 166 class DUIterator_Fast;
 167 class DUIterator_Last;
 168 #else
 169 typedef uint   DUIterator;
 170 typedef Node** DUIterator_Fast;
 171 typedef Node** DUIterator_Last;
 172 #endif
 173 
 174 // Node Sentinel
 175 #define NodeSentinel (Node*)-1
 176 
 177 // Unknown count frequency
 178 #define COUNT_UNKNOWN (-1.0f)
 179 
 180 //------------------------------Node-------------------------------------------
 181 // Nodes define actions in the program.  They create values, which have types.
 182 // They are both vertices in a directed graph and program primitives.  Nodes
 183 // are labeled; the label is the "opcode", the primitive function in the lambda
 184 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 185 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 186 // the Node's function.  These inputs also define a Type equation for the Node.
 187 // Solving these Type equations amounts to doing dataflow analysis.
 188 // Control and data are uniformly represented in the graph.  Finally, Nodes
 189 // have a unique dense integer index which is used to index into side arrays
 190 // whenever I have phase-specific information.
 191 
 192 class Node {
 193   friend class VMStructs;
 194 
 195   // Lots of restrictions on cloning Nodes
 196   Node(const Node&);            // not defined; linker error to use these
 197   Node &operator=(const Node &rhs);
 198 
 199 public:
 200   friend class Compile;
 201   #if OPTO_DU_ITERATOR_ASSERT
 202   friend class DUIterator_Common;
 203   friend class DUIterator;
 204   friend class DUIterator_Fast;
 205   friend class DUIterator_Last;
 206   #endif
 207 
 208   // Because Nodes come and go, I define an Arena of Node structures to pull
 209   // from.  This should allow fast access to node creation & deletion.  This
 210   // field is a local cache of a value defined in some "program fragment" for
 211   // which these Nodes are just a part of.
 212 
 213   inline void* operator new(size_t x) throw() {
 214     Compile* C = Compile::current();
 215     Node* n = (Node*)C->node_arena()->Amalloc_D(x);
 216 #ifdef ASSERT
 217     n->_in = (Node**)n; // magic cookie for assertion check
 218 #endif
 219     return (void*)n;
 220   }
 221 
 222   // Delete is a NOP
 223   void operator delete( void *ptr ) {}
 224   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 225   void destruct();
 226 
 227   // Create a new Node.  Required is the number is of inputs required for
 228   // semantic correctness.
 229   Node( uint required );
 230 
 231   // Create a new Node with given input edges.
 232   // This version requires use of the "edge-count" new.
 233   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 234   Node( Node *n0 );
 235   Node( Node *n0, Node *n1 );
 236   Node( Node *n0, Node *n1, Node *n2 );
 237   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 238   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 239   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 240   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 241             Node *n4, Node *n5, Node *n6 );
 242 
 243   // Clone an inherited Node given only the base Node type.
 244   Node* clone() const;
 245 
 246   // Clone a Node, immediately supplying one or two new edges.
 247   // The first and second arguments, if non-null, replace in(1) and in(2),
 248   // respectively.
 249   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 250     Node* nn = clone();
 251     if (in1 != NULL)  nn->set_req(1, in1);
 252     if (in2 != NULL)  nn->set_req(2, in2);
 253     return nn;
 254   }
 255 
 256 private:
 257   // Shared setup for the above constructors.
 258   // Handles all interactions with Compile::current.
 259   // Puts initial values in all Node fields except _idx.
 260   // Returns the initial value for _idx, which cannot
 261   // be initialized by assignment.
 262   inline int Init(int req);
 263 
 264 //----------------- input edge handling
 265 protected:
 266   friend class PhaseCFG;        // Access to address of _in array elements
 267   Node **_in;                   // Array of use-def references to Nodes
 268   Node **_out;                  // Array of def-use references to Nodes
 269 
 270   // Input edges are split into two categories.  Required edges are required
 271   // for semantic correctness; order is important and NULLs are allowed.
 272   // Precedence edges are used to help determine execution order and are
 273   // added, e.g., for scheduling purposes.  They are unordered and not
 274   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 275   // are required, from _cnt to _max-1 are precedence edges.
 276   node_idx_t _cnt;              // Total number of required Node inputs.
 277 
 278   node_idx_t _max;              // Actual length of input array.
 279 
 280   // Output edges are an unordered list of def-use edges which exactly
 281   // correspond to required input edges which point from other nodes
 282   // to this one.  Thus the count of the output edges is the number of
 283   // users of this node.
 284   node_idx_t _outcnt;           // Total number of Node outputs.
 285 
 286   node_idx_t _outmax;           // Actual length of output array.
 287 
 288   // Grow the actual input array to the next larger power-of-2 bigger than len.
 289   void grow( uint len );
 290   // Grow the output array to the next larger power-of-2 bigger than len.
 291   void out_grow( uint len );
 292 
 293  public:
 294   // Each Node is assigned a unique small/dense number.  This number is used
 295   // to index into auxiliary arrays of data and bitvectors.
 296   // It is declared const to defend against inadvertant assignment,
 297   // since it is used by clients as a naked field.
 298   const node_idx_t _idx;
 299 
 300   // Get the (read-only) number of input edges
 301   uint req() const { return _cnt; }
 302   uint len() const { return _max; }
 303   // Get the (read-only) number of output edges
 304   uint outcnt() const { return _outcnt; }
 305 
 306 #if OPTO_DU_ITERATOR_ASSERT
 307   // Iterate over the out-edges of this node.  Deletions are illegal.
 308   inline DUIterator outs() const;
 309   // Use this when the out array might have changed to suppress asserts.
 310   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 311   // Does the node have an out at this position?  (Used for iteration.)
 312   inline bool has_out(DUIterator& i) const;
 313   inline Node*    out(DUIterator& i) const;
 314   // Iterate over the out-edges of this node.  All changes are illegal.
 315   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 316   inline Node*    fast_out(DUIterator_Fast& i) const;
 317   // Iterate over the out-edges of this node, deleting one at a time.
 318   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 319   inline Node*    last_out(DUIterator_Last& i) const;
 320   // The inline bodies of all these methods are after the iterator definitions.
 321 #else
 322   // Iterate over the out-edges of this node.  Deletions are illegal.
 323   // This iteration uses integral indexes, to decouple from array reallocations.
 324   DUIterator outs() const  { return 0; }
 325   // Use this when the out array might have changed to suppress asserts.
 326   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 327 
 328   // Reference to the i'th output Node.  Error if out of bounds.
 329   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 330   // Does the node have an out at this position?  (Used for iteration.)
 331   bool has_out(DUIterator i) const { return i < _outcnt; }
 332 
 333   // Iterate over the out-edges of this node.  All changes are illegal.
 334   // This iteration uses a pointer internal to the out array.
 335   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 336     Node** out = _out;
 337     // Assign a limit pointer to the reference argument:
 338     max = out + (ptrdiff_t)_outcnt;
 339     // Return the base pointer:
 340     return out;
 341   }
 342   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 343   // Iterate over the out-edges of this node, deleting one at a time.
 344   // This iteration uses a pointer internal to the out array.
 345   DUIterator_Last last_outs(DUIterator_Last& min) const {
 346     Node** out = _out;
 347     // Assign a limit pointer to the reference argument:
 348     min = out;
 349     // Return the pointer to the start of the iteration:
 350     return out + (ptrdiff_t)_outcnt - 1;
 351   }
 352   Node*    last_out(DUIterator_Last i) const  { return *i; }
 353 #endif
 354 
 355   // Reference to the i'th input Node.  Error if out of bounds.
 356   Node* in(uint i) const { assert(i < _max, err_msg_res("oob: i=%d, _max=%d", i, _max)); return _in[i]; }
 357   // Reference to the i'th input Node.  NULL if out of bounds.
 358   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 359   // Reference to the i'th output Node.  Error if out of bounds.
 360   // Use this accessor sparingly.  We are going trying to use iterators instead.
 361   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 362   // Return the unique out edge.
 363   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 364   // Delete out edge at position 'i' by moving last out edge to position 'i'
 365   void  raw_del_out(uint i) {
 366     assert(i < _outcnt,"oob");
 367     assert(_outcnt > 0,"oob");
 368     #if OPTO_DU_ITERATOR_ASSERT
 369     // Record that a change happened here.
 370     debug_only(_last_del = _out[i]; ++_del_tick);
 371     #endif
 372     _out[i] = _out[--_outcnt];
 373     // Smash the old edge so it can't be used accidentally.
 374     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 375   }
 376 
 377 #ifdef ASSERT
 378   bool is_dead() const;
 379 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 380 #endif
 381   // Check whether node has become unreachable
 382   bool is_unreachable(PhaseIterGVN &igvn) const;
 383 
 384   // Set a required input edge, also updates corresponding output edge
 385   void add_req( Node *n ); // Append a NEW required input
 386   void add_req( Node *n0, Node *n1 ) {
 387     add_req(n0); add_req(n1); }
 388   void add_req( Node *n0, Node *n1, Node *n2 ) {
 389     add_req(n0); add_req(n1); add_req(n2); }
 390   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 391   void del_req( uint idx ); // Delete required edge & compact
 392   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 393   void ins_req( uint i, Node *n ); // Insert a NEW required input
 394   void set_req( uint i, Node *n ) {
 395     assert( is_not_dead(n), "can not use dead node");
 396     assert( i < _cnt, err_msg_res("oob: i=%d, _cnt=%d", i, _cnt));
 397     assert( !VerifyHashTableKeys || _hash_lock == 0,
 398             "remove node from hash table before modifying it");
 399     Node** p = &_in[i];    // cache this._in, across the del_out call
 400     if (*p != NULL)  (*p)->del_out((Node *)this);
 401     (*p) = n;
 402     if (n != NULL)      n->add_out((Node *)this);
 403     Compile::current()->record_modified_node(this);
 404   }
 405   // Light version of set_req() to init inputs after node creation.
 406   void init_req( uint i, Node *n ) {
 407     assert( i == 0 && this == n ||
 408             is_not_dead(n), "can not use dead node");
 409     assert( i < _cnt, "oob");
 410     assert( !VerifyHashTableKeys || _hash_lock == 0,
 411             "remove node from hash table before modifying it");
 412     assert( _in[i] == NULL, "sanity");
 413     _in[i] = n;
 414     if (n != NULL)      n->add_out((Node *)this);
 415     Compile::current()->record_modified_node(this);
 416   }
 417   // Find first occurrence of n among my edges:
 418   int find_edge(Node* n);
 419   int replace_edge(Node* old, Node* neww);
 420   int replace_edges_in_range(Node* old, Node* neww, int start, int end);
 421   // NULL out all inputs to eliminate incoming Def-Use edges.
 422   // Return the number of edges between 'n' and 'this'
 423   int  disconnect_inputs(Node *n, Compile *c);
 424 
 425   // Quickly, return true if and only if I am Compile::current()->top().
 426   bool is_top() const {
 427     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 428     return (_out == NULL);
 429   }
 430   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 431   void setup_is_top();
 432 
 433   // Strip away casting.  (It is depth-limited.)
 434   Node* uncast() const;
 435   // Return whether two Nodes are equivalent, after stripping casting.
 436   bool eqv_uncast(const Node* n) const {
 437     return (this->uncast() == n->uncast());
 438   }
 439 
 440   // Find out of current node that matches opcode.
 441   Node* find_out_with(int opcode);
 442   // Return true if the current node has an out that matches opcode.
 443   bool has_out_with(int opcode);
 444   // Return true if the current node has an out that matches any of the opcodes.
 445   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 446 
 447 private:
 448   static Node* uncast_helper(const Node* n);
 449 
 450   // Add an output edge to the end of the list
 451   void add_out( Node *n ) {
 452     if (is_top())  return;
 453     if( _outcnt == _outmax ) out_grow(_outcnt);
 454     _out[_outcnt++] = n;
 455   }
 456   // Delete an output edge
 457   void del_out( Node *n ) {
 458     if (is_top())  return;
 459     Node** outp = &_out[_outcnt];
 460     // Find and remove n
 461     do {
 462       assert(outp > _out, "Missing Def-Use edge");
 463     } while (*--outp != n);
 464     *outp = _out[--_outcnt];
 465     // Smash the old edge so it can't be used accidentally.
 466     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 467     // Record that a change happened here.
 468     #if OPTO_DU_ITERATOR_ASSERT
 469     debug_only(_last_del = n; ++_del_tick);
 470     #endif
 471   }
 472 
 473 public:
 474   // Globally replace this node by a given new node, updating all uses.
 475   void replace_by(Node* new_node);
 476   // Globally replace this node by a given new node, updating all uses
 477   // and cutting input edges of old node.
 478   void subsume_by(Node* new_node, Compile* c) {
 479     replace_by(new_node);
 480     disconnect_inputs(NULL, c);
 481   }
 482   void set_req_X( uint i, Node *n, PhaseIterGVN *igvn );
 483   // Find the one non-null required input.  RegionNode only
 484   Node *nonnull_req() const;
 485   // Add or remove precedence edges
 486   void add_prec( Node *n );
 487   void rm_prec( uint i );
 488   void set_prec( uint i, Node *n ) {
 489     assert( is_not_dead(n), "can not use dead node");
 490     assert( i >= _cnt, "not a precedence edge");
 491     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 492     _in[i] = n;
 493     if (n != NULL) n->add_out((Node *)this);
 494   }
 495   // Set this node's index, used by cisc_version to replace current node
 496   void set_idx(uint new_idx) {
 497     const node_idx_t* ref = &_idx;
 498     *(node_idx_t*)ref = new_idx;
 499   }
 500   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 501   void swap_edges(uint i1, uint i2) {
 502     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 503     // Def-Use info is unchanged
 504     Node* n1 = in(i1);
 505     Node* n2 = in(i2);
 506     _in[i1] = n2;
 507     _in[i2] = n1;
 508     // If this node is in the hash table, make sure it doesn't need a rehash.
 509     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 510   }
 511 
 512   // Iterators over input Nodes for a Node X are written as:
 513   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 514   // NOTE: Required edges can contain embedded NULL pointers.
 515 
 516 //----------------- Other Node Properties
 517 
 518   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 519   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 520   //
 521   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 522   // the type of the node the ID represents; another subset of an ID's bits are reserved
 523   // for the superclasses of the node represented by the ID.
 524   //
 525   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 526   // returns false. A.is_A() returns true.
 527   //
 528   // If two classes, A and B, have the same superclass, a different bit of A's class id
 529   // is reserved for A's type than for B's type. That bit is specified by the third
 530   // parameter in the macro DEFINE_CLASS_ID.
 531   //
 532   // By convention, classes with deeper hierarchy are declared first. Moreover,
 533   // classes with the same hierarchy depth are sorted by usage frequency.
 534   //
 535   // The query method masks the bits to cut off bits of subclasses and then compares
 536   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 537   //
 538   //  Class_MachCall=30, ClassMask_MachCall=31
 539   // 12               8               4               0
 540   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 541   //                                  |   |   |   |
 542   //                                  |   |   |   Bit_Mach=2
 543   //                                  |   |   Bit_MachReturn=4
 544   //                                  |   Bit_MachSafePoint=8
 545   //                                  Bit_MachCall=16
 546   //
 547   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 548   // 12               8               4               0
 549   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 550   //                              |   |   |
 551   //                              |   |   Bit_Region=8
 552   //                              |   Bit_Loop=16
 553   //                              Bit_CountedLoop=32
 554 
 555   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 556   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 557   Class_##cl = Class_##supcl + Bit_##cl , \
 558   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 559 
 560   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 561   // so that it's values fits into 16 bits.
 562   enum NodeClasses {
 563     Bit_Node   = 0x0000,
 564     Class_Node = 0x0000,
 565     ClassMask_Node = 0xFFFF,
 566 
 567     DEFINE_CLASS_ID(Multi, Node, 0)
 568       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 569         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 570           DEFINE_CLASS_ID(CallJava,         Call, 0)
 571             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 572             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 573           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 574             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 575           DEFINE_CLASS_ID(Allocate,         Call, 2)
 576             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 577           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 578             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 579             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 580           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 581       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 582         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 583           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 584           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 585         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 586           DEFINE_CLASS_ID(CountedLoopEnd, If, 0)
 587         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 588       DEFINE_CLASS_ID(Start,       Multi, 2)
 589       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 590         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 591         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 592 
 593     DEFINE_CLASS_ID(Mach,  Node, 1)
 594       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 595         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 596           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 597             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 598               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 599               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 600             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 601               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 602       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 603         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 604         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 605         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 606       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 607       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 608       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 609       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 610       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 611 
 612     DEFINE_CLASS_ID(Type,  Node, 2)
 613       DEFINE_CLASS_ID(Phi,   Type, 0)
 614       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 615       DEFINE_CLASS_ID(CheckCastPP, Type, 2)
 616       DEFINE_CLASS_ID(CMove, Type, 3)
 617       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 618       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 619         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 620         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 621       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 622         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 623         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 624 
 625     DEFINE_CLASS_ID(Proj,  Node, 3)
 626       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 627       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 628       DEFINE_CLASS_ID(IfTrue,    Proj, 2)
 629       DEFINE_CLASS_ID(IfFalse,   Proj, 3)
 630       DEFINE_CLASS_ID(Parm,      Proj, 4)
 631       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 632 
 633     DEFINE_CLASS_ID(Mem,   Node, 4)
 634       DEFINE_CLASS_ID(Load,  Mem, 0)
 635         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 636       DEFINE_CLASS_ID(Store, Mem, 1)
 637         DEFINE_CLASS_ID(StoreVector, Store, 0)
 638       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 639 
 640     DEFINE_CLASS_ID(Region, Node, 5)
 641       DEFINE_CLASS_ID(Loop, Region, 0)
 642         DEFINE_CLASS_ID(Root,        Loop, 0)
 643         DEFINE_CLASS_ID(CountedLoop, Loop, 1)
 644 
 645     DEFINE_CLASS_ID(Sub,   Node, 6)
 646       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 647         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 648         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 649 
 650     DEFINE_CLASS_ID(MergeMem, Node, 7)
 651     DEFINE_CLASS_ID(Bool,     Node, 8)
 652     DEFINE_CLASS_ID(AddP,     Node, 9)
 653     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 654     DEFINE_CLASS_ID(Add,      Node, 11)
 655     DEFINE_CLASS_ID(Mul,      Node, 12)
 656     DEFINE_CLASS_ID(Vector,   Node, 13)
 657     DEFINE_CLASS_ID(ClearArray, Node, 14)
 658 
 659     _max_classes  = ClassMask_ClearArray
 660   };
 661   #undef DEFINE_CLASS_ID
 662 
 663   // Flags are sorted by usage frequency.
 664   enum NodeFlags {
 665     Flag_is_Copy                     = 0x01, // should be first bit to avoid shift
 666     Flag_rematerialize               = Flag_is_Copy << 1,
 667     Flag_needs_anti_dependence_check = Flag_rematerialize << 1,
 668     Flag_is_macro                    = Flag_needs_anti_dependence_check << 1,
 669     Flag_is_Con                      = Flag_is_macro << 1,
 670     Flag_is_cisc_alternate           = Flag_is_Con << 1,
 671     Flag_is_dead_loop_safe           = Flag_is_cisc_alternate << 1,
 672     Flag_may_be_short_branch         = Flag_is_dead_loop_safe << 1,
 673     Flag_avoid_back_to_back_before   = Flag_may_be_short_branch << 1,
 674     Flag_avoid_back_to_back_after    = Flag_avoid_back_to_back_before << 1,
 675     Flag_has_call                    = Flag_avoid_back_to_back_after << 1,
 676     Flag_is_reduction                = Flag_has_call << 1,
 677     Flag_is_scheduled                = Flag_is_reduction << 1,
 678     Flag_is_expensive                = Flag_is_scheduled << 1,
 679     _max_flags = (Flag_is_expensive << 1) - 1 // allow flags combination
 680   };
 681 
 682 private:
 683   jushort _class_id;
 684   jushort _flags;
 685 
 686 protected:
 687   // These methods should be called from constructors only.
 688   void init_class_id(jushort c) {
 689     assert(c <= _max_classes, "invalid node class");
 690     _class_id = c; // cast out const
 691   }
 692   void init_flags(jushort fl) {
 693     assert(fl <= _max_flags, "invalid node flag");
 694     _flags |= fl;
 695   }
 696   void clear_flag(jushort fl) {
 697     assert(fl <= _max_flags, "invalid node flag");
 698     _flags &= ~fl;
 699   }
 700 
 701 public:
 702   const jushort class_id() const { return _class_id; }
 703 
 704   const jushort flags() const { return _flags; }
 705 
 706   void add_flag(jushort fl) { init_flags(fl); }
 707 
 708   void remove_flag(jushort fl) { clear_flag(fl); }
 709 
 710   // Return a dense integer opcode number
 711   virtual int Opcode() const;
 712 
 713   // Virtual inherited Node size
 714   virtual uint size_of() const;
 715 
 716   // Other interesting Node properties
 717   #define DEFINE_CLASS_QUERY(type)                           \
 718   bool is_##type() const {                                   \
 719     return ((_class_id & ClassMask_##type) == Class_##type); \
 720   }                                                          \
 721   type##Node *as_##type() const {                            \
 722     assert(is_##type(), "invalid node class");               \
 723     return (type##Node*)this;                                \
 724   }                                                          \
 725   type##Node* isa_##type() const {                           \
 726     return (is_##type()) ? as_##type() : NULL;               \
 727   }
 728 
 729   DEFINE_CLASS_QUERY(AbstractLock)
 730   DEFINE_CLASS_QUERY(Add)
 731   DEFINE_CLASS_QUERY(AddP)
 732   DEFINE_CLASS_QUERY(Allocate)
 733   DEFINE_CLASS_QUERY(AllocateArray)
 734   DEFINE_CLASS_QUERY(ArrayCopy)
 735   DEFINE_CLASS_QUERY(Bool)
 736   DEFINE_CLASS_QUERY(BoxLock)
 737   DEFINE_CLASS_QUERY(Call)
 738   DEFINE_CLASS_QUERY(CallDynamicJava)
 739   DEFINE_CLASS_QUERY(CallJava)
 740   DEFINE_CLASS_QUERY(CallLeaf)
 741   DEFINE_CLASS_QUERY(CallRuntime)
 742   DEFINE_CLASS_QUERY(CallStaticJava)
 743   DEFINE_CLASS_QUERY(Catch)
 744   DEFINE_CLASS_QUERY(CatchProj)
 745   DEFINE_CLASS_QUERY(CheckCastPP)
 746   DEFINE_CLASS_QUERY(ConstraintCast)
 747   DEFINE_CLASS_QUERY(ClearArray)
 748   DEFINE_CLASS_QUERY(CMove)
 749   DEFINE_CLASS_QUERY(Cmp)
 750   DEFINE_CLASS_QUERY(CountedLoop)
 751   DEFINE_CLASS_QUERY(CountedLoopEnd)
 752   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 753   DEFINE_CLASS_QUERY(DecodeN)
 754   DEFINE_CLASS_QUERY(DecodeNKlass)
 755   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 756   DEFINE_CLASS_QUERY(EncodeP)
 757   DEFINE_CLASS_QUERY(EncodePKlass)
 758   DEFINE_CLASS_QUERY(FastLock)
 759   DEFINE_CLASS_QUERY(FastUnlock)
 760   DEFINE_CLASS_QUERY(If)
 761   DEFINE_CLASS_QUERY(IfFalse)
 762   DEFINE_CLASS_QUERY(IfTrue)
 763   DEFINE_CLASS_QUERY(Initialize)
 764   DEFINE_CLASS_QUERY(Jump)
 765   DEFINE_CLASS_QUERY(JumpProj)
 766   DEFINE_CLASS_QUERY(Load)
 767   DEFINE_CLASS_QUERY(LoadStore)
 768   DEFINE_CLASS_QUERY(Lock)
 769   DEFINE_CLASS_QUERY(Loop)
 770   DEFINE_CLASS_QUERY(Mach)
 771   DEFINE_CLASS_QUERY(MachBranch)
 772   DEFINE_CLASS_QUERY(MachCall)
 773   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 774   DEFINE_CLASS_QUERY(MachCallJava)
 775   DEFINE_CLASS_QUERY(MachCallLeaf)
 776   DEFINE_CLASS_QUERY(MachCallRuntime)
 777   DEFINE_CLASS_QUERY(MachCallStaticJava)
 778   DEFINE_CLASS_QUERY(MachConstantBase)
 779   DEFINE_CLASS_QUERY(MachConstant)
 780   DEFINE_CLASS_QUERY(MachGoto)
 781   DEFINE_CLASS_QUERY(MachIf)
 782   DEFINE_CLASS_QUERY(MachNullCheck)
 783   DEFINE_CLASS_QUERY(MachProj)
 784   DEFINE_CLASS_QUERY(MachReturn)
 785   DEFINE_CLASS_QUERY(MachSafePoint)
 786   DEFINE_CLASS_QUERY(MachSpillCopy)
 787   DEFINE_CLASS_QUERY(MachTemp)
 788   DEFINE_CLASS_QUERY(MachMerge)
 789   DEFINE_CLASS_QUERY(Mem)
 790   DEFINE_CLASS_QUERY(MemBar)
 791   DEFINE_CLASS_QUERY(MemBarStoreStore)
 792   DEFINE_CLASS_QUERY(MergeMem)
 793   DEFINE_CLASS_QUERY(Mul)
 794   DEFINE_CLASS_QUERY(Multi)
 795   DEFINE_CLASS_QUERY(MultiBranch)
 796   DEFINE_CLASS_QUERY(Parm)
 797   DEFINE_CLASS_QUERY(PCTable)
 798   DEFINE_CLASS_QUERY(Phi)
 799   DEFINE_CLASS_QUERY(Proj)
 800   DEFINE_CLASS_QUERY(Region)
 801   DEFINE_CLASS_QUERY(Root)
 802   DEFINE_CLASS_QUERY(SafePoint)
 803   DEFINE_CLASS_QUERY(SafePointScalarObject)
 804   DEFINE_CLASS_QUERY(Start)
 805   DEFINE_CLASS_QUERY(Store)
 806   DEFINE_CLASS_QUERY(Sub)
 807   DEFINE_CLASS_QUERY(Type)
 808   DEFINE_CLASS_QUERY(Vector)
 809   DEFINE_CLASS_QUERY(LoadVector)
 810   DEFINE_CLASS_QUERY(StoreVector)
 811   DEFINE_CLASS_QUERY(Unlock)
 812 
 813   #undef DEFINE_CLASS_QUERY
 814 
 815   // duplicate of is_MachSpillCopy()
 816   bool is_SpillCopy () const {
 817     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 818   }
 819 
 820   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 821   // The data node which is safe to leave in dead loop during IGVN optimization.
 822   bool is_dead_loop_safe() const {
 823     return is_Phi() || (is_Proj() && in(0) == NULL) ||
 824            ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0 &&
 825             (!is_Proj() || !in(0)->is_Allocate()));
 826   }
 827 
 828   // is_Copy() returns copied edge index (0 or 1)
 829   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 830 
 831   virtual bool is_CFG() const { return false; }
 832 
 833   // If this node is control-dependent on a test, can it be
 834   // rerouted to a dominating equivalent test?  This is usually
 835   // true of non-CFG nodes, but can be false for operations which
 836   // depend for their correct sequencing on more than one test.
 837   // (In that case, hoisting to a dominating test may silently
 838   // skip some other important test.)
 839   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 840 
 841   // When building basic blocks, I need to have a notion of block beginning
 842   // Nodes, next block selector Nodes (block enders), and next block
 843   // projections.  These calls need to work on their machine equivalents.  The
 844   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 845   bool is_block_start() const {
 846     if ( is_Region() )
 847       return this == (const Node*)in(0);
 848     else
 849       return is_Start();
 850   }
 851 
 852   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 853   // Goto and Return.  This call also returns the block ending Node.
 854   virtual const Node *is_block_proj() const;
 855 
 856   // The node is a "macro" node which needs to be expanded before matching
 857   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 858   // The node is expensive: the best control is set during loop opts
 859   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 860 
 861   // An arithmetic node which accumulates a data in a loop.
 862   // It must have the loop's phi as input and provide a def to the phi.
 863   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 864 
 865   // Used in lcm to mark nodes that have scheduled
 866   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
 867 
 868 //----------------- Optimization
 869 
 870   // Get the worst-case Type output for this Node.
 871   virtual const class Type *bottom_type() const;
 872 
 873   // If we find a better type for a node, try to record it permanently.
 874   // Return true if this node actually changed.
 875   // Be sure to do the hash_delete game in the "rehash" variant.
 876   void raise_bottom_type(const Type* new_type);
 877 
 878   // Get the address type with which this node uses and/or defs memory,
 879   // or NULL if none.  The address type is conservatively wide.
 880   // Returns non-null for calls, membars, loads, stores, etc.
 881   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
 882   virtual const class TypePtr *adr_type() const { return NULL; }
 883 
 884   // Return an existing node which computes the same function as this node.
 885   // The optimistic combined algorithm requires this to return a Node which
 886   // is a small number of steps away (e.g., one of my inputs).
 887   virtual Node *Identity( PhaseTransform *phase );
 888 
 889   // Return the set of values this Node can take on at runtime.
 890   virtual const Type *Value( PhaseTransform *phase ) const;
 891 
 892   // Return a node which is more "ideal" than the current node.
 893   // The invariants on this call are subtle.  If in doubt, read the
 894   // treatise in node.cpp above the default implemention AND TEST WITH
 895   // +VerifyIterativeGVN!
 896   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 897 
 898   // Some nodes have specific Ideal subgraph transformations only if they are
 899   // unique users of specific nodes. Such nodes should be put on IGVN worklist
 900   // for the transformations to happen.
 901   bool has_special_unique_user() const;
 902 
 903   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
 904   Node* find_exact_control(Node* ctrl);
 905 
 906   // Check if 'this' node dominates or equal to 'sub'.
 907   bool dominates(Node* sub, Node_List &nlist);
 908 
 909 protected:
 910   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
 911 public:
 912 
 913   // See if there is valid pipeline info
 914   static  const Pipeline *pipeline_class();
 915   virtual const Pipeline *pipeline() const;
 916 
 917   // Compute the latency from the def to this instruction of the ith input node
 918   uint latency(uint i);
 919 
 920   // Hash & compare functions, for pessimistic value numbering
 921 
 922   // If the hash function returns the special sentinel value NO_HASH,
 923   // the node is guaranteed never to compare equal to any other node.
 924   // If we accidentally generate a hash with value NO_HASH the node
 925   // won't go into the table and we'll lose a little optimization.
 926   enum { NO_HASH = 0 };
 927   virtual uint hash() const;
 928   virtual uint cmp( const Node &n ) const;
 929 
 930   // Operation appears to be iteratively computed (such as an induction variable)
 931   // It is possible for this operation to return false for a loop-varying
 932   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
 933   bool is_iteratively_computed();
 934 
 935   // Determine if a node is Counted loop induction variable.
 936   // The method is defined in loopnode.cpp.
 937   const Node* is_loop_iv() const;
 938 
 939   // Return a node with opcode "opc" and same inputs as "this" if one can
 940   // be found; Otherwise return NULL;
 941   Node* find_similar(int opc);
 942 
 943   // Return the unique control out if only one. Null if none or more than one.
 944   Node* unique_ctrl_out() const;
 945 
 946   // Set control or add control as precedence edge
 947   void ensure_control_or_add_prec(Node* c);
 948 
 949 //----------------- Code Generation
 950 
 951   // Ideal register class for Matching.  Zero means unmatched instruction
 952   // (these are cloned instead of converted to machine nodes).
 953   virtual uint ideal_reg() const;
 954 
 955   static const uint NotAMachineReg;   // must be > max. machine register
 956 
 957   // Do we Match on this edge index or not?  Generally false for Control
 958   // and true for everything else.  Weird for calls & returns.
 959   virtual uint match_edge(uint idx) const;
 960 
 961   // Register class output is returned in
 962   virtual const RegMask &out_RegMask() const;
 963   // Register class input is expected in
 964   virtual const RegMask &in_RegMask(uint) const;
 965   // Should we clone rather than spill this instruction?
 966   bool rematerialize() const;
 967 
 968   // Return JVM State Object if this Node carries debug info, or NULL otherwise
 969   virtual JVMState* jvms() const;
 970 
 971   // Print as assembly
 972   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
 973   // Emit bytes starting at parameter 'ptr'
 974   // Bump 'ptr' by the number of output bytes
 975   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
 976   // Size of instruction in bytes
 977   virtual uint size(PhaseRegAlloc *ra_) const;
 978 
 979   // Convenience function to extract an integer constant from a node.
 980   // If it is not an integer constant (either Con, CastII, or Mach),
 981   // return value_if_unknown.
 982   jint find_int_con(jint value_if_unknown) const {
 983     const TypeInt* t = find_int_type();
 984     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
 985   }
 986   // Return the constant, knowing it is an integer constant already
 987   jint get_int() const {
 988     const TypeInt* t = find_int_type();
 989     guarantee(t != NULL, "must be con");
 990     return t->get_con();
 991   }
 992   // Here's where the work is done.  Can produce non-constant int types too.
 993   const TypeInt* find_int_type() const;
 994 
 995   // Same thing for long (and intptr_t, via type.hpp):
 996   jlong get_long() const {
 997     const TypeLong* t = find_long_type();
 998     guarantee(t != NULL, "must be con");
 999     return t->get_con();
1000   }
1001   jlong find_long_con(jint value_if_unknown) const {
1002     const TypeLong* t = find_long_type();
1003     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1004   }
1005   const TypeLong* find_long_type() const;
1006 
1007   const TypePtr* get_ptr_type() const;
1008 
1009   // These guys are called by code generated by ADLC:
1010   intptr_t get_ptr() const;
1011   intptr_t get_narrowcon() const;
1012   jdouble getd() const;
1013   jfloat getf() const;
1014 
1015   // Nodes which are pinned into basic blocks
1016   virtual bool pinned() const { return false; }
1017 
1018   // Nodes which use memory without consuming it, hence need antidependences
1019   // More specifically, needs_anti_dependence_check returns true iff the node
1020   // (a) does a load, and (b) does not perform a store (except perhaps to a
1021   // stack slot or some other unaliased location).
1022   bool needs_anti_dependence_check() const;
1023 
1024   // Return which operand this instruction may cisc-spill. In other words,
1025   // return operand position that can convert from reg to memory access
1026   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1027   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1028 
1029 //----------------- Graph walking
1030 public:
1031   // Walk and apply member functions recursively.
1032   // Supplied (this) pointer is root.
1033   void walk(NFunc pre, NFunc post, void *env);
1034   static void nop(Node &, void*); // Dummy empty function
1035   static void packregion( Node &n, void* );
1036 private:
1037   void walk_(NFunc pre, NFunc post, void *env, VectorSet &visited);
1038 
1039 //----------------- Printing, etc
1040 public:
1041 #ifndef PRODUCT
1042   Node* find(int idx) const;         // Search the graph for the given idx.
1043   Node* find_ctrl(int idx) const;    // Search control ancestors for the given idx.
1044   void dump() const { dump("\n"); }  // Print this node.
1045   void dump(const char* suffix, outputStream *st = tty) const;// Print this node.
1046   void dump(int depth) const;        // Print this node, recursively to depth d
1047   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1048   virtual void dump_req(outputStream *st = tty) const;     // Print required-edge info
1049   virtual void dump_prec(outputStream *st = tty) const;    // Print precedence-edge info
1050   virtual void dump_out(outputStream *st = tty) const;     // Print the output edge info
1051   virtual void dump_spec(outputStream *st) const {}; // Print per-node info
1052   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1053   void verify() const;               // Check Def-Use info for my subgraph
1054   static void verify_recur(const Node *n, int verify_depth, VectorSet &old_space, VectorSet &new_space);
1055 
1056   // This call defines a class-unique string used to identify class instances
1057   virtual const char *Name() const;
1058 
1059   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1060   // RegMask Print Functions
1061   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1062   void dump_out_regmask() { out_RegMask().dump(); }
1063   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1064   void fast_dump() const {
1065     tty->print("%4d: %-17s", _idx, Name());
1066     for (uint i = 0; i < len(); i++)
1067       if (in(i))
1068         tty->print(" %4d", in(i)->_idx);
1069       else
1070         tty->print(" NULL");
1071     tty->print("\n");
1072   }
1073 #endif
1074 #ifdef ASSERT
1075   void verify_construction();
1076   bool verify_jvms(const JVMState* jvms) const;
1077   int  _debug_idx;                     // Unique value assigned to every node.
1078   int   debug_idx() const              { return _debug_idx; }
1079   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1080 
1081   Node* _debug_orig;                   // Original version of this, if any.
1082   Node*  debug_orig() const            { return _debug_orig; }
1083   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1084 
1085   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1086   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1087   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1088 
1089   static void init_NodeProperty();
1090 
1091   #if OPTO_DU_ITERATOR_ASSERT
1092   const Node* _last_del;               // The last deleted node.
1093   uint        _del_tick;               // Bumped when a deletion happens..
1094   #endif
1095 #endif
1096 };
1097 
1098 //-----------------------------------------------------------------------------
1099 // Iterators over DU info, and associated Node functions.
1100 
1101 #if OPTO_DU_ITERATOR_ASSERT
1102 
1103 // Common code for assertion checking on DU iterators.
1104 class DUIterator_Common VALUE_OBJ_CLASS_SPEC {
1105 #ifdef ASSERT
1106  protected:
1107   bool         _vdui;               // cached value of VerifyDUIterators
1108   const Node*  _node;               // the node containing the _out array
1109   uint         _outcnt;             // cached node->_outcnt
1110   uint         _del_tick;           // cached node->_del_tick
1111   Node*        _last;               // last value produced by the iterator
1112 
1113   void sample(const Node* node);    // used by c'tor to set up for verifies
1114   void verify(const Node* node, bool at_end_ok = false);
1115   void verify_resync();
1116   void reset(const DUIterator_Common& that);
1117 
1118 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1119   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1120 #else
1121   #define I_VDUI_ONLY(i,x) { }
1122 #endif //ASSERT
1123 };
1124 
1125 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1126 
1127 // Default DU iterator.  Allows appends onto the out array.
1128 // Allows deletion from the out array only at the current point.
1129 // Usage:
1130 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1131 //    Node* y = x->out(i);
1132 //    ...
1133 //  }
1134 // Compiles in product mode to a unsigned integer index, which indexes
1135 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1136 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1137 // before continuing the loop.  You must delete only the last-produced
1138 // edge.  You must delete only a single copy of the last-produced edge,
1139 // or else you must delete all copies at once (the first time the edge
1140 // is produced by the iterator).
1141 class DUIterator : public DUIterator_Common {
1142   friend class Node;
1143 
1144   // This is the index which provides the product-mode behavior.
1145   // Whatever the product-mode version of the system does to the
1146   // DUI index is done to this index.  All other fields in
1147   // this class are used only for assertion checking.
1148   uint         _idx;
1149 
1150   #ifdef ASSERT
1151   uint         _refresh_tick;    // Records the refresh activity.
1152 
1153   void sample(const Node* node); // Initialize _refresh_tick etc.
1154   void verify(const Node* node, bool at_end_ok = false);
1155   void verify_increment();       // Verify an increment operation.
1156   void verify_resync();          // Verify that we can back up over a deletion.
1157   void verify_finish();          // Verify that the loop terminated properly.
1158   void refresh();                // Resample verification info.
1159   void reset(const DUIterator& that);  // Resample after assignment.
1160   #endif
1161 
1162   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1163     { _idx = 0;                         debug_only(sample(node)); }
1164 
1165  public:
1166   // initialize to garbage; clear _vdui to disable asserts
1167   DUIterator()
1168     { /*initialize to garbage*/         debug_only(_vdui = false); }
1169 
1170   void operator++(int dummy_to_specify_postfix_op)
1171     { _idx++;                           VDUI_ONLY(verify_increment()); }
1172 
1173   void operator--()
1174     { VDUI_ONLY(verify_resync());       --_idx; }
1175 
1176   ~DUIterator()
1177     { VDUI_ONLY(verify_finish()); }
1178 
1179   void operator=(const DUIterator& that)
1180     { _idx = that._idx;                 debug_only(reset(that)); }
1181 };
1182 
1183 DUIterator Node::outs() const
1184   { return DUIterator(this, 0); }
1185 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1186   { I_VDUI_ONLY(i, i.refresh());        return i; }
1187 bool Node::has_out(DUIterator& i) const
1188   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1189 Node*    Node::out(DUIterator& i) const
1190   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1191 
1192 
1193 // Faster DU iterator.  Disallows insertions into the out array.
1194 // Allows deletion from the out array only at the current point.
1195 // Usage:
1196 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1197 //    Node* y = x->fast_out(i);
1198 //    ...
1199 //  }
1200 // Compiles in product mode to raw Node** pointer arithmetic, with
1201 // no reloading of pointers from the original node x.  If you delete,
1202 // you must perform "--i; --imax" just before continuing the loop.
1203 // If you delete multiple copies of the same edge, you must decrement
1204 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1205 class DUIterator_Fast : public DUIterator_Common {
1206   friend class Node;
1207   friend class DUIterator_Last;
1208 
1209   // This is the pointer which provides the product-mode behavior.
1210   // Whatever the product-mode version of the system does to the
1211   // DUI pointer is done to this pointer.  All other fields in
1212   // this class are used only for assertion checking.
1213   Node**       _outp;
1214 
1215   #ifdef ASSERT
1216   void verify(const Node* node, bool at_end_ok = false);
1217   void verify_limit();
1218   void verify_resync();
1219   void verify_relimit(uint n);
1220   void reset(const DUIterator_Fast& that);
1221   #endif
1222 
1223   // Note:  offset must be signed, since -1 is sometimes passed
1224   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1225     { _outp = node->_out + offset;      debug_only(sample(node)); }
1226 
1227  public:
1228   // initialize to garbage; clear _vdui to disable asserts
1229   DUIterator_Fast()
1230     { /*initialize to garbage*/         debug_only(_vdui = false); }
1231 
1232   void operator++(int dummy_to_specify_postfix_op)
1233     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1234 
1235   void operator--()
1236     { VDUI_ONLY(verify_resync());       --_outp; }
1237 
1238   void operator-=(uint n)   // applied to the limit only
1239     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1240 
1241   bool operator<(DUIterator_Fast& limit) {
1242     I_VDUI_ONLY(*this, this->verify(_node, true));
1243     I_VDUI_ONLY(limit, limit.verify_limit());
1244     return _outp < limit._outp;
1245   }
1246 
1247   void operator=(const DUIterator_Fast& that)
1248     { _outp = that._outp;               debug_only(reset(that)); }
1249 };
1250 
1251 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1252   // Assign a limit pointer to the reference argument:
1253   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1254   // Return the base pointer:
1255   return DUIterator_Fast(this, 0);
1256 }
1257 Node* Node::fast_out(DUIterator_Fast& i) const {
1258   I_VDUI_ONLY(i, i.verify(this));
1259   return debug_only(i._last=) *i._outp;
1260 }
1261 
1262 
1263 // Faster DU iterator.  Requires each successive edge to be removed.
1264 // Does not allow insertion of any edges.
1265 // Usage:
1266 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1267 //    Node* y = x->last_out(i);
1268 //    ...
1269 //  }
1270 // Compiles in product mode to raw Node** pointer arithmetic, with
1271 // no reloading of pointers from the original node x.
1272 class DUIterator_Last : private DUIterator_Fast {
1273   friend class Node;
1274 
1275   #ifdef ASSERT
1276   void verify(const Node* node, bool at_end_ok = false);
1277   void verify_limit();
1278   void verify_step(uint num_edges);
1279   #endif
1280 
1281   // Note:  offset must be signed, since -1 is sometimes passed
1282   DUIterator_Last(const Node* node, ptrdiff_t offset)
1283     : DUIterator_Fast(node, offset) { }
1284 
1285   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1286   void operator<(int)                              {} // do not use
1287 
1288  public:
1289   DUIterator_Last() { }
1290   // initialize to garbage
1291 
1292   void operator--()
1293     { _outp--;              VDUI_ONLY(verify_step(1));  }
1294 
1295   void operator-=(uint n)
1296     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1297 
1298   bool operator>=(DUIterator_Last& limit) {
1299     I_VDUI_ONLY(*this, this->verify(_node, true));
1300     I_VDUI_ONLY(limit, limit.verify_limit());
1301     return _outp >= limit._outp;
1302   }
1303 
1304   void operator=(const DUIterator_Last& that)
1305     { DUIterator_Fast::operator=(that); }
1306 };
1307 
1308 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1309   // Assign a limit pointer to the reference argument:
1310   imin = DUIterator_Last(this, 0);
1311   // Return the initial pointer:
1312   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1313 }
1314 Node* Node::last_out(DUIterator_Last& i) const {
1315   I_VDUI_ONLY(i, i.verify(this));
1316   return debug_only(i._last=) *i._outp;
1317 }
1318 
1319 #endif //OPTO_DU_ITERATOR_ASSERT
1320 
1321 #undef I_VDUI_ONLY
1322 #undef VDUI_ONLY
1323 
1324 // An Iterator that truly follows the iterator pattern.  Doesn't
1325 // support deletion but could be made to.
1326 //
1327 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1328 //     Node* m = i.get();
1329 //
1330 class SimpleDUIterator : public StackObj {
1331  private:
1332   Node* node;
1333   DUIterator_Fast i;
1334   DUIterator_Fast imax;
1335  public:
1336   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1337   bool has_next() { return i < imax; }
1338   void next() { i++; }
1339   Node* get() { return node->fast_out(i); }
1340 };
1341 
1342 
1343 //-----------------------------------------------------------------------------
1344 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1345 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1346 // Note that the constructor just zeros things, and since I use Arena
1347 // allocation I do not need a destructor to reclaim storage.
1348 class Node_Array : public ResourceObj {
1349   friend class VMStructs;
1350 protected:
1351   Arena *_a;                    // Arena to allocate in
1352   uint   _max;
1353   Node **_nodes;
1354   void   grow( uint i );        // Grow array node to fit
1355 public:
1356   Node_Array(Arena *a) : _a(a), _max(OptoNodeListSize) {
1357     _nodes = NEW_ARENA_ARRAY( a, Node *, OptoNodeListSize );
1358     for( int i = 0; i < OptoNodeListSize; i++ ) {
1359       _nodes[i] = NULL;
1360     }
1361   }
1362 
1363   Node_Array(Node_Array *na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1364   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1365   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1366   Node *at( uint i ) const { assert(i<_max,"oob"); return _nodes[i]; }
1367   Node **adr() { return _nodes; }
1368   // Extend the mapping: index i maps to Node *n.
1369   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1370   void insert( uint i, Node *n );
1371   void remove( uint i );        // Remove, preserving order
1372   void sort( C_sort_func_t func);
1373   void reset( Arena *new_a );   // Zap mapping to empty; reclaim storage
1374   void clear();                 // Set all entries to NULL, keep storage
1375   uint Size() const { return _max; }
1376   void dump() const;
1377 };
1378 
1379 class Node_List : public Node_Array {
1380   friend class VMStructs;
1381   uint _cnt;
1382 public:
1383   Node_List() : Node_Array(Thread::current()->resource_area()), _cnt(0) {}
1384   Node_List(Arena *a) : Node_Array(a), _cnt(0) {}
1385   bool contains(const Node* n) const {
1386     for (uint e = 0; e < size(); e++) {
1387       if (at(e) == n) return true;
1388     }
1389     return false;
1390   }
1391   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1392   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1393   void push( Node *b ) { map(_cnt++,b); }
1394   void yank( Node *n );         // Find and remove
1395   Node *pop() { return _nodes[--_cnt]; }
1396   Node *rpop() { Node *b = _nodes[0]; _nodes[0]=_nodes[--_cnt]; return b;}
1397   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1398   uint size() const { return _cnt; }
1399   void dump() const;
1400 };
1401 
1402 //------------------------------Unique_Node_List-------------------------------
1403 class Unique_Node_List : public Node_List {
1404   friend class VMStructs;
1405   VectorSet _in_worklist;
1406   uint _clock_index;            // Index in list where to pop from next
1407 public:
1408   Unique_Node_List() : Node_List(), _in_worklist(Thread::current()->resource_area()), _clock_index(0) {}
1409   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1410 
1411   void remove( Node *n );
1412   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1413   VectorSet &member_set(){ return _in_worklist; }
1414 
1415   void push( Node *b ) {
1416     if( !_in_worklist.test_set(b->_idx) )
1417       Node_List::push(b);
1418   }
1419   Node *pop() {
1420     if( _clock_index >= size() ) _clock_index = 0;
1421     Node *b = at(_clock_index);
1422     map( _clock_index, Node_List::pop());
1423     if (size() != 0) _clock_index++; // Always start from 0
1424     _in_worklist >>= b->_idx;
1425     return b;
1426   }
1427   Node *remove( uint i ) {
1428     Node *b = Node_List::at(i);
1429     _in_worklist >>= b->_idx;
1430     map(i,Node_List::pop());
1431     return b;
1432   }
1433   void yank( Node *n ) { _in_worklist >>= n->_idx; Node_List::yank(n); }
1434   void  clear() {
1435     _in_worklist.Clear();        // Discards storage but grows automatically
1436     Node_List::clear();
1437     _clock_index = 0;
1438   }
1439 
1440   // Used after parsing to remove useless nodes before Iterative GVN
1441   void remove_useless_nodes(VectorSet &useful);
1442 
1443 #ifndef PRODUCT
1444   void print_set() const { _in_worklist.print(); }
1445 #endif
1446 };
1447 
1448 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1449 inline void Compile::record_for_igvn(Node* n) {
1450   _for_igvn->push(n);
1451 }
1452 
1453 //------------------------------Node_Stack-------------------------------------
1454 class Node_Stack {
1455   friend class VMStructs;
1456 protected:
1457   struct INode {
1458     Node *node; // Processed node
1459     uint  indx; // Index of next node's child
1460   };
1461   INode *_inode_top; // tos, stack grows up
1462   INode *_inode_max; // End of _inodes == _inodes + _max
1463   INode *_inodes;    // Array storage for the stack
1464   Arena *_a;         // Arena to allocate in
1465   void grow();
1466 public:
1467   Node_Stack(int size) {
1468     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1469     _a = Thread::current()->resource_area();
1470     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1471     _inode_max = _inodes + max;
1472     _inode_top = _inodes - 1; // stack is empty
1473   }
1474 
1475   Node_Stack(Arena *a, int size) : _a(a) {
1476     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1477     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1478     _inode_max = _inodes + max;
1479     _inode_top = _inodes - 1; // stack is empty
1480   }
1481 
1482   void pop() {
1483     assert(_inode_top >= _inodes, "node stack underflow");
1484     --_inode_top;
1485   }
1486   void push(Node *n, uint i) {
1487     ++_inode_top;
1488     if (_inode_top >= _inode_max) grow();
1489     INode *top = _inode_top; // optimization
1490     top->node = n;
1491     top->indx = i;
1492   }
1493   Node *node() const {
1494     return _inode_top->node;
1495   }
1496   Node* node_at(uint i) const {
1497     assert(_inodes + i <= _inode_top, "in range");
1498     return _inodes[i].node;
1499   }
1500   uint index() const {
1501     return _inode_top->indx;
1502   }
1503   uint index_at(uint i) const {
1504     assert(_inodes + i <= _inode_top, "in range");
1505     return _inodes[i].indx;
1506   }
1507   void set_node(Node *n) {
1508     _inode_top->node = n;
1509   }
1510   void set_index(uint i) {
1511     _inode_top->indx = i;
1512   }
1513   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1514   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1515   bool is_nonempty() const { return (_inode_top >= _inodes); }
1516   bool is_empty() const { return (_inode_top < _inodes); }
1517   void clear() { _inode_top = _inodes - 1; } // retain storage
1518 
1519   // Node_Stack is used to map nodes.
1520   Node* find(uint idx) const;
1521 };
1522 
1523 
1524 //-----------------------------Node_Notes--------------------------------------
1525 // Debugging or profiling annotations loosely and sparsely associated
1526 // with some nodes.  See Compile::node_notes_at for the accessor.
1527 class Node_Notes VALUE_OBJ_CLASS_SPEC {
1528   friend class VMStructs;
1529   JVMState* _jvms;
1530 
1531 public:
1532   Node_Notes(JVMState* jvms = NULL) {
1533     _jvms = jvms;
1534   }
1535 
1536   JVMState* jvms()            { return _jvms; }
1537   void  set_jvms(JVMState* x) {        _jvms = x; }
1538 
1539   // True if there is nothing here.
1540   bool is_clear() {
1541     return (_jvms == NULL);
1542   }
1543 
1544   // Make there be nothing here.
1545   void clear() {
1546     _jvms = NULL;
1547   }
1548 
1549   // Make a new, clean node notes.
1550   static Node_Notes* make(Compile* C) {
1551     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1552     nn->clear();
1553     return nn;
1554   }
1555 
1556   Node_Notes* clone(Compile* C) {
1557     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1558     (*nn) = (*this);
1559     return nn;
1560   }
1561 
1562   // Absorb any information from source.
1563   bool update_from(Node_Notes* source) {
1564     bool changed = false;
1565     if (source != NULL) {
1566       if (source->jvms() != NULL) {
1567         set_jvms(source->jvms());
1568         changed = true;
1569       }
1570     }
1571     return changed;
1572   }
1573 };
1574 
1575 // Inlined accessors for Compile::node_nodes that require the preceding class:
1576 inline Node_Notes*
1577 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1578                            int idx, bool can_grow) {
1579   assert(idx >= 0, "oob");
1580   int block_idx = (idx >> _log2_node_notes_block_size);
1581   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1582   if (grow_by >= 0) {
1583     if (!can_grow)  return NULL;
1584     grow_node_notes(arr, grow_by + 1);
1585   }
1586   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1587   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1588 }
1589 
1590 inline bool
1591 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1592   if (value == NULL || value->is_clear())
1593     return false;  // nothing to write => write nothing
1594   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1595   assert(loc != NULL, "");
1596   return loc->update_from(value);
1597 }
1598 
1599 
1600 //------------------------------TypeNode---------------------------------------
1601 // Node with a Type constant.
1602 class TypeNode : public Node {
1603 protected:
1604   virtual uint hash() const;    // Check the type
1605   virtual uint cmp( const Node &n ) const;
1606   virtual uint size_of() const; // Size is bigger
1607   const Type* const _type;
1608 public:
1609   void set_type(const Type* t) {
1610     assert(t != NULL, "sanity");
1611     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1612     *(const Type**)&_type = t;   // cast away const-ness
1613     // If this node is in the hash table, make sure it doesn't need a rehash.
1614     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1615   }
1616   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1617   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1618     init_class_id(Class_Type);
1619   }
1620   virtual const Type *Value( PhaseTransform *phase ) const;
1621   virtual const Type *bottom_type() const;
1622   virtual       uint  ideal_reg() const;
1623 #ifndef PRODUCT
1624   virtual void dump_spec(outputStream *st) const;
1625 #endif
1626 };
1627 
1628 #endif // SHARE_VM_OPTO_NODE_HPP