1 /*
   2  * Copyright (c) 1997, 2015, 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.
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  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 RangeCheckNode;
 129 class RegMask;
 130 class RegionNode;
 131 class RootNode;
 132 class SafePointNode;
 133 class SafePointScalarObjectNode;
 134 class StartNode;
 135 class State;
 136 class StoreNode;
 137 class SubNode;
 138 class Type;
 139 class TypeNode;
 140 class UnlockNode;
 141 class VectorNode;
 142 class LoadVectorNode;
 143 class StoreVectorNode;
 144 class VectorSet;
 145 typedef void (*NFunc)(Node&,void*);
 146 extern "C" {
 147   typedef int (*C_sort_func_t)(const void *, const void *);
 148 }
 149 
 150 // The type of all node counts and indexes.
 151 // It must hold at least 16 bits, but must also be fast to load and store.
 152 // This type, if less than 32 bits, could limit the number of possible nodes.
 153 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 154 typedef unsigned int node_idx_t;
 155 
 156 
 157 #ifndef OPTO_DU_ITERATOR_ASSERT
 158 #ifdef ASSERT
 159 #define OPTO_DU_ITERATOR_ASSERT 1
 160 #else
 161 #define OPTO_DU_ITERATOR_ASSERT 0
 162 #endif
 163 #endif //OPTO_DU_ITERATOR_ASSERT
 164 
 165 #if OPTO_DU_ITERATOR_ASSERT
 166 class DUIterator;
 167 class DUIterator_Fast;
 168 class DUIterator_Last;
 169 #else
 170 typedef uint   DUIterator;
 171 typedef Node** DUIterator_Fast;
 172 typedef Node** DUIterator_Last;
 173 #endif
 174 
 175 // Node Sentinel
 176 #define NodeSentinel (Node*)-1
 177 
 178 // Unknown count frequency
 179 #define COUNT_UNKNOWN (-1.0f)
 180 
 181 //------------------------------Node-------------------------------------------
 182 // Nodes define actions in the program.  They create values, which have types.
 183 // They are both vertices in a directed graph and program primitives.  Nodes
 184 // are labeled; the label is the "opcode", the primitive function in the lambda
 185 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 186 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 187 // the Node's function.  These inputs also define a Type equation for the Node.
 188 // Solving these Type equations amounts to doing dataflow analysis.
 189 // Control and data are uniformly represented in the graph.  Finally, Nodes
 190 // have a unique dense integer index which is used to index into side arrays
 191 // whenever I have phase-specific information.
 192 
 193 class Node {
 194   friend class VMStructs;
 195 
 196   // Lots of restrictions on cloning Nodes
 197   Node(const Node&);            // not defined; linker error to use these
 198   Node &operator=(const Node &rhs);
 199 
 200 public:
 201   friend class Compile;
 202   #if OPTO_DU_ITERATOR_ASSERT
 203   friend class DUIterator_Common;
 204   friend class DUIterator;
 205   friend class DUIterator_Fast;
 206   friend class DUIterator_Last;
 207   #endif
 208 
 209   // Because Nodes come and go, I define an Arena of Node structures to pull
 210   // from.  This should allow fast access to node creation & deletion.  This
 211   // field is a local cache of a value defined in some "program fragment" for
 212   // which these Nodes are just a part of.
 213 
 214   inline void* operator new(size_t x) throw() {
 215     Compile* C = Compile::current();
 216     Node* n = (Node*)C->node_arena()->Amalloc_D(x);
 217 #ifdef ASSERT
 218     n->_in = (Node**)n; // magic cookie for assertion check
 219 #endif
 220     return (void*)n;
 221   }
 222 
 223   // Delete is a NOP
 224   void operator delete( void *ptr ) {}
 225   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 226   void destruct();
 227 
 228   // Create a new Node.  Required is the number is of inputs required for
 229   // semantic correctness.
 230   Node( uint required );
 231 
 232   // Create a new Node with given input edges.
 233   // This version requires use of the "edge-count" new.
 234   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 235   Node( Node *n0 );
 236   Node( Node *n0, Node *n1 );
 237   Node( Node *n0, Node *n1, Node *n2 );
 238   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 239   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 240   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 241   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 242             Node *n4, Node *n5, Node *n6 );
 243 
 244   // Clone an inherited Node given only the base Node type.
 245   Node* clone() const;
 246 
 247   // Clone a Node, immediately supplying one or two new edges.
 248   // The first and second arguments, if non-null, replace in(1) and in(2),
 249   // respectively.
 250   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 251     Node* nn = clone();
 252     if (in1 != NULL)  nn->set_req(1, in1);
 253     if (in2 != NULL)  nn->set_req(2, in2);
 254     return nn;
 255   }
 256 
 257 private:
 258   // Shared setup for the above constructors.
 259   // Handles all interactions with Compile::current.
 260   // Puts initial values in all Node fields except _idx.
 261   // Returns the initial value for _idx, which cannot
 262   // be initialized by assignment.
 263   inline int Init(int req);
 264 
 265 //----------------- input edge handling
 266 protected:
 267   friend class PhaseCFG;        // Access to address of _in array elements
 268   Node **_in;                   // Array of use-def references to Nodes
 269   Node **_out;                  // Array of def-use references to Nodes
 270 
 271   // Input edges are split into two categories.  Required edges are required
 272   // for semantic correctness; order is important and NULLs are allowed.
 273   // Precedence edges are used to help determine execution order and are
 274   // added, e.g., for scheduling purposes.  They are unordered and not
 275   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 276   // are required, from _cnt to _max-1 are precedence edges.
 277   node_idx_t _cnt;              // Total number of required Node inputs.
 278 
 279   node_idx_t _max;              // Actual length of input array.
 280 
 281   // Output edges are an unordered list of def-use edges which exactly
 282   // correspond to required input edges which point from other nodes
 283   // to this one.  Thus the count of the output edges is the number of
 284   // users of this node.
 285   node_idx_t _outcnt;           // Total number of Node outputs.
 286 
 287   node_idx_t _outmax;           // Actual length of output array.
 288 
 289   // Grow the actual input array to the next larger power-of-2 bigger than len.
 290   void grow( uint len );
 291   // Grow the output array to the next larger power-of-2 bigger than len.
 292   void out_grow( uint len );
 293 
 294  public:
 295   // Each Node is assigned a unique small/dense number.  This number is used
 296   // to index into auxiliary arrays of data and bitvectors.
 297   // It is declared const to defend against inadvertant assignment,
 298   // since it is used by clients as a naked field.
 299   const node_idx_t _idx;
 300 
 301   // Get the (read-only) number of input edges
 302   uint req() const { return _cnt; }
 303   uint len() const { return _max; }
 304   // Get the (read-only) number of output edges
 305   uint outcnt() const { return _outcnt; }
 306 
 307 #if OPTO_DU_ITERATOR_ASSERT
 308   // Iterate over the out-edges of this node.  Deletions are illegal.
 309   inline DUIterator outs() const;
 310   // Use this when the out array might have changed to suppress asserts.
 311   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 312   // Does the node have an out at this position?  (Used for iteration.)
 313   inline bool has_out(DUIterator& i) const;
 314   inline Node*    out(DUIterator& i) const;
 315   // Iterate over the out-edges of this node.  All changes are illegal.
 316   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 317   inline Node*    fast_out(DUIterator_Fast& i) const;
 318   // Iterate over the out-edges of this node, deleting one at a time.
 319   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 320   inline Node*    last_out(DUIterator_Last& i) const;
 321   // The inline bodies of all these methods are after the iterator definitions.
 322 #else
 323   // Iterate over the out-edges of this node.  Deletions are illegal.
 324   // This iteration uses integral indexes, to decouple from array reallocations.
 325   DUIterator outs() const  { return 0; }
 326   // Use this when the out array might have changed to suppress asserts.
 327   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 328 
 329   // Reference to the i'th output Node.  Error if out of bounds.
 330   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 331   // Does the node have an out at this position?  (Used for iteration.)
 332   bool has_out(DUIterator i) const { return i < _outcnt; }
 333 
 334   // Iterate over the out-edges of this node.  All changes are illegal.
 335   // This iteration uses a pointer internal to the out array.
 336   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 337     Node** out = _out;
 338     // Assign a limit pointer to the reference argument:
 339     max = out + (ptrdiff_t)_outcnt;
 340     // Return the base pointer:
 341     return out;
 342   }
 343   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 344   // Iterate over the out-edges of this node, deleting one at a time.
 345   // This iteration uses a pointer internal to the out array.
 346   DUIterator_Last last_outs(DUIterator_Last& min) const {
 347     Node** out = _out;
 348     // Assign a limit pointer to the reference argument:
 349     min = out;
 350     // Return the pointer to the start of the iteration:
 351     return out + (ptrdiff_t)_outcnt - 1;
 352   }
 353   Node*    last_out(DUIterator_Last i) const  { return *i; }
 354 #endif
 355 
 356   // Reference to the i'th input Node.  Error if out of bounds.
 357   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 358   // Reference to the i'th input Node.  NULL if out of bounds.
 359   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 360   // Reference to the i'th output Node.  Error if out of bounds.
 361   // Use this accessor sparingly.  We are going trying to use iterators instead.
 362   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 363   // Return the unique out edge.
 364   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 365   // Delete out edge at position 'i' by moving last out edge to position 'i'
 366   void  raw_del_out(uint i) {
 367     assert(i < _outcnt,"oob");
 368     assert(_outcnt > 0,"oob");
 369     #if OPTO_DU_ITERATOR_ASSERT
 370     // Record that a change happened here.
 371     debug_only(_last_del = _out[i]; ++_del_tick);
 372     #endif
 373     _out[i] = _out[--_outcnt];
 374     // Smash the old edge so it can't be used accidentally.
 375     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 376   }
 377 
 378 #ifdef ASSERT
 379   bool is_dead() const;
 380 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 381 #endif
 382   // Check whether node has become unreachable
 383   bool is_unreachable(PhaseIterGVN &igvn) const;
 384 
 385   // Set a required input edge, also updates corresponding output edge
 386   void add_req( Node *n ); // Append a NEW required input
 387   void add_req( Node *n0, Node *n1 ) {
 388     add_req(n0); add_req(n1); }
 389   void add_req( Node *n0, Node *n1, Node *n2 ) {
 390     add_req(n0); add_req(n1); add_req(n2); }
 391   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 392   void del_req( uint idx ); // Delete required edge & compact
 393   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 394   void ins_req( uint i, Node *n ); // Insert a NEW required input
 395   void set_req( uint i, Node *n ) {
 396     assert( is_not_dead(n), "can not use dead node");
 397     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 398     assert( !VerifyHashTableKeys || _hash_lock == 0,
 399             "remove node from hash table before modifying it");
 400     Node** p = &_in[i];    // cache this._in, across the del_out call
 401     if (*p != NULL)  (*p)->del_out((Node *)this);
 402     (*p) = n;
 403     if (n != NULL)      n->add_out((Node *)this);
 404     Compile::current()->record_modified_node(this);
 405   }
 406   // Light version of set_req() to init inputs after node creation.
 407   void init_req( uint i, Node *n ) {
 408     assert( i == 0 && this == n ||
 409             is_not_dead(n), "can not use dead node");
 410     assert( i < _cnt, "oob");
 411     assert( !VerifyHashTableKeys || _hash_lock == 0,
 412             "remove node from hash table before modifying it");
 413     assert( _in[i] == NULL, "sanity");
 414     _in[i] = n;
 415     if (n != NULL)      n->add_out((Node *)this);
 416     Compile::current()->record_modified_node(this);
 417   }
 418   // Find first occurrence of n among my edges:
 419   int find_edge(Node* n);
 420   int replace_edge(Node* old, Node* neww);
 421   int replace_edges_in_range(Node* old, Node* neww, int start, int end);
 422   // NULL out all inputs to eliminate incoming Def-Use edges.
 423   // Return the number of edges between 'n' and 'this'
 424   int  disconnect_inputs(Node *n, Compile *c);
 425 
 426   // Quickly, return true if and only if I am Compile::current()->top().
 427   bool is_top() const {
 428     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 429     return (_out == NULL);
 430   }
 431   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 432   void setup_is_top();
 433 
 434   // Strip away casting.  (It is depth-limited.)
 435   Node* uncast() const;
 436   // Return whether two Nodes are equivalent, after stripping casting.
 437   bool eqv_uncast(const Node* n) const {
 438     return (this->uncast() == n->uncast());
 439   }
 440 
 441   // Find out of current node that matches opcode.
 442   Node* find_out_with(int opcode);
 443   // Return true if the current node has an out that matches opcode.
 444   bool has_out_with(int opcode);
 445   // Return true if the current node has an out that matches any of the opcodes.
 446   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 447 
 448 private:
 449   static Node* uncast_helper(const Node* n);
 450 
 451   // Add an output edge to the end of the list
 452   void add_out( Node *n ) {
 453     if (is_top())  return;
 454     if( _outcnt == _outmax ) out_grow(_outcnt);
 455     _out[_outcnt++] = n;
 456   }
 457   // Delete an output edge
 458   void del_out( Node *n ) {
 459     if (is_top())  return;
 460     Node** outp = &_out[_outcnt];
 461     // Find and remove n
 462     do {
 463       assert(outp > _out, "Missing Def-Use edge");
 464     } while (*--outp != n);
 465     *outp = _out[--_outcnt];
 466     // Smash the old edge so it can't be used accidentally.
 467     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 468     // Record that a change happened here.
 469     #if OPTO_DU_ITERATOR_ASSERT
 470     debug_only(_last_del = n; ++_del_tick);
 471     #endif
 472   }
 473 
 474 public:
 475   // Globally replace this node by a given new node, updating all uses.
 476   void replace_by(Node* new_node);
 477   // Globally replace this node by a given new node, updating all uses
 478   // and cutting input edges of old node.
 479   void subsume_by(Node* new_node, Compile* c) {
 480     replace_by(new_node);
 481     disconnect_inputs(NULL, c);
 482   }
 483   void set_req_X( uint i, Node *n, PhaseIterGVN *igvn );
 484   // Find the one non-null required input.  RegionNode only
 485   Node *nonnull_req() const;
 486   // Add or remove precedence edges
 487   void add_prec( Node *n );
 488   void rm_prec( uint i );
 489   void set_prec( uint i, Node *n ) {
 490     assert( is_not_dead(n), "can not use dead node");
 491     assert( i >= _cnt, "not a precedence edge");
 492     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 493     _in[i] = n;
 494     if (n != NULL) n->add_out((Node *)this);
 495   }
 496   // Set this node's index, used by cisc_version to replace current node
 497   void set_idx(uint new_idx) {
 498     const node_idx_t* ref = &_idx;
 499     *(node_idx_t*)ref = new_idx;
 500   }
 501   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 502   void swap_edges(uint i1, uint i2) {
 503     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 504     // Def-Use info is unchanged
 505     Node* n1 = in(i1);
 506     Node* n2 = in(i2);
 507     _in[i1] = n2;
 508     _in[i2] = n1;
 509     // If this node is in the hash table, make sure it doesn't need a rehash.
 510     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 511   }
 512 
 513   // Iterators over input Nodes for a Node X are written as:
 514   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 515   // NOTE: Required edges can contain embedded NULL pointers.
 516 
 517 //----------------- Other Node Properties
 518 
 519   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 520   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 521   //
 522   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 523   // the type of the node the ID represents; another subset of an ID's bits are reserved
 524   // for the superclasses of the node represented by the ID.
 525   //
 526   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 527   // returns false. A.is_A() returns true.
 528   //
 529   // If two classes, A and B, have the same superclass, a different bit of A's class id
 530   // is reserved for A's type than for B's type. That bit is specified by the third
 531   // parameter in the macro DEFINE_CLASS_ID.
 532   //
 533   // By convention, classes with deeper hierarchy are declared first. Moreover,
 534   // classes with the same hierarchy depth are sorted by usage frequency.
 535   //
 536   // The query method masks the bits to cut off bits of subclasses and then compares
 537   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 538   //
 539   //  Class_MachCall=30, ClassMask_MachCall=31
 540   // 12               8               4               0
 541   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 542   //                                  |   |   |   |
 543   //                                  |   |   |   Bit_Mach=2
 544   //                                  |   |   Bit_MachReturn=4
 545   //                                  |   Bit_MachSafePoint=8
 546   //                                  Bit_MachCall=16
 547   //
 548   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 549   // 12               8               4               0
 550   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 551   //                              |   |   |
 552   //                              |   |   Bit_Region=8
 553   //                              |   Bit_Loop=16
 554   //                              Bit_CountedLoop=32
 555 
 556   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 557   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 558   Class_##cl = Class_##supcl + Bit_##cl , \
 559   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 560 
 561   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 562   // so that it's values fits into 16 bits.
 563   enum NodeClasses {
 564     Bit_Node   = 0x0000,
 565     Class_Node = 0x0000,
 566     ClassMask_Node = 0xFFFF,
 567 
 568     DEFINE_CLASS_ID(Multi, Node, 0)
 569       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 570         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 571           DEFINE_CLASS_ID(CallJava,         Call, 0)
 572             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 573             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 574           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 575             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 576           DEFINE_CLASS_ID(Allocate,         Call, 2)
 577             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 578           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 579             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 580             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 581           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 582       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 583         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 584           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 585           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 586         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 587           DEFINE_CLASS_ID(CountedLoopEnd, If, 0)
 588           DEFINE_CLASS_ID(RangeCheck, If, 1)
 589         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 590       DEFINE_CLASS_ID(Start,       Multi, 2)
 591       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 592         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 593         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 594 
 595     DEFINE_CLASS_ID(Mach,  Node, 1)
 596       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 597         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 598           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 599             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 600               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 601               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 602             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 603               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 604       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 605         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 606         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 607         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 608       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 609       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 610       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 611       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 612       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 613 
 614     DEFINE_CLASS_ID(Type,  Node, 2)
 615       DEFINE_CLASS_ID(Phi,   Type, 0)
 616       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 617       DEFINE_CLASS_ID(CheckCastPP, Type, 2)
 618       DEFINE_CLASS_ID(CMove, Type, 3)
 619       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 620       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 621         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 622         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 623       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 624         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 625         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 626 
 627     DEFINE_CLASS_ID(Proj,  Node, 3)
 628       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 629       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 630       DEFINE_CLASS_ID(IfTrue,    Proj, 2)
 631       DEFINE_CLASS_ID(IfFalse,   Proj, 3)
 632       DEFINE_CLASS_ID(Parm,      Proj, 4)
 633       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 634 
 635     DEFINE_CLASS_ID(Mem,   Node, 4)
 636       DEFINE_CLASS_ID(Load,  Mem, 0)
 637         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 638       DEFINE_CLASS_ID(Store, Mem, 1)
 639         DEFINE_CLASS_ID(StoreVector, Store, 0)
 640       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 641 
 642     DEFINE_CLASS_ID(Region, Node, 5)
 643       DEFINE_CLASS_ID(Loop, Region, 0)
 644         DEFINE_CLASS_ID(Root,        Loop, 0)
 645         DEFINE_CLASS_ID(CountedLoop, Loop, 1)
 646 
 647     DEFINE_CLASS_ID(Sub,   Node, 6)
 648       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 649         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 650         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 651 
 652     DEFINE_CLASS_ID(MergeMem, Node, 7)
 653     DEFINE_CLASS_ID(Bool,     Node, 8)
 654     DEFINE_CLASS_ID(AddP,     Node, 9)
 655     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 656     DEFINE_CLASS_ID(Add,      Node, 11)
 657     DEFINE_CLASS_ID(Mul,      Node, 12)
 658     DEFINE_CLASS_ID(Vector,   Node, 13)
 659     DEFINE_CLASS_ID(ClearArray, Node, 14)
 660 
 661     _max_classes  = ClassMask_ClearArray
 662   };
 663   #undef DEFINE_CLASS_ID
 664 
 665   // Flags are sorted by usage frequency.
 666   enum NodeFlags {
 667     Flag_is_Copy                     = 0x01, // should be first bit to avoid shift
 668     Flag_rematerialize               = Flag_is_Copy << 1,
 669     Flag_needs_anti_dependence_check = Flag_rematerialize << 1,
 670     Flag_is_macro                    = Flag_needs_anti_dependence_check << 1,
 671     Flag_is_Con                      = Flag_is_macro << 1,
 672     Flag_is_cisc_alternate           = Flag_is_Con << 1,
 673     Flag_is_dead_loop_safe           = Flag_is_cisc_alternate << 1,
 674     Flag_may_be_short_branch         = Flag_is_dead_loop_safe << 1,
 675     Flag_avoid_back_to_back_before   = Flag_may_be_short_branch << 1,
 676     Flag_avoid_back_to_back_after    = Flag_avoid_back_to_back_before << 1,
 677     Flag_has_call                    = Flag_avoid_back_to_back_after << 1,
 678     Flag_is_reduction                = Flag_has_call << 1,
 679     Flag_is_scheduled                = Flag_is_reduction,
 680     Flag_is_expensive                = Flag_is_scheduled << 1,
 681     _max_flags = (Flag_is_expensive << 1) - 1 // allow flags combination
 682   };
 683 
 684 private:
 685   jushort _class_id;
 686   jushort _flags;
 687 
 688 protected:
 689   // These methods should be called from constructors only.
 690   void init_class_id(jushort c) {
 691     assert(c <= _max_classes, "invalid node class");
 692     _class_id = c; // cast out const
 693   }
 694   void init_flags(jushort fl) {
 695     assert(fl <= _max_flags, "invalid node flag");
 696     _flags |= fl;
 697   }
 698   void clear_flag(jushort fl) {
 699     assert(fl <= _max_flags, "invalid node flag");
 700     _flags &= ~fl;
 701   }
 702 
 703 public:
 704   const jushort class_id() const { return _class_id; }
 705 
 706   const jushort flags() const { return _flags; }
 707 
 708   void add_flag(jushort fl) { init_flags(fl); }
 709 
 710   void remove_flag(jushort fl) { clear_flag(fl); }
 711 
 712   // Return a dense integer opcode number
 713   virtual int Opcode() const;
 714 
 715   // Virtual inherited Node size
 716   virtual uint size_of() const;
 717 
 718   // Other interesting Node properties
 719   #define DEFINE_CLASS_QUERY(type)                           \
 720   bool is_##type() const {                                   \
 721     return ((_class_id & ClassMask_##type) == Class_##type); \
 722   }                                                          \
 723   type##Node *as_##type() const {                            \
 724     assert(is_##type(), "invalid node class");               \
 725     return (type##Node*)this;                                \
 726   }                                                          \
 727   type##Node* isa_##type() const {                           \
 728     return (is_##type()) ? as_##type() : NULL;               \
 729   }
 730 
 731   DEFINE_CLASS_QUERY(AbstractLock)
 732   DEFINE_CLASS_QUERY(Add)
 733   DEFINE_CLASS_QUERY(AddP)
 734   DEFINE_CLASS_QUERY(Allocate)
 735   DEFINE_CLASS_QUERY(AllocateArray)
 736   DEFINE_CLASS_QUERY(ArrayCopy)
 737   DEFINE_CLASS_QUERY(Bool)
 738   DEFINE_CLASS_QUERY(BoxLock)
 739   DEFINE_CLASS_QUERY(Call)
 740   DEFINE_CLASS_QUERY(CallDynamicJava)
 741   DEFINE_CLASS_QUERY(CallJava)
 742   DEFINE_CLASS_QUERY(CallLeaf)
 743   DEFINE_CLASS_QUERY(CallRuntime)
 744   DEFINE_CLASS_QUERY(CallStaticJava)
 745   DEFINE_CLASS_QUERY(Catch)
 746   DEFINE_CLASS_QUERY(CatchProj)
 747   DEFINE_CLASS_QUERY(CheckCastPP)
 748   DEFINE_CLASS_QUERY(ConstraintCast)
 749   DEFINE_CLASS_QUERY(ClearArray)
 750   DEFINE_CLASS_QUERY(CMove)
 751   DEFINE_CLASS_QUERY(Cmp)
 752   DEFINE_CLASS_QUERY(CountedLoop)
 753   DEFINE_CLASS_QUERY(CountedLoopEnd)
 754   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 755   DEFINE_CLASS_QUERY(DecodeN)
 756   DEFINE_CLASS_QUERY(DecodeNKlass)
 757   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 758   DEFINE_CLASS_QUERY(EncodeP)
 759   DEFINE_CLASS_QUERY(EncodePKlass)
 760   DEFINE_CLASS_QUERY(FastLock)
 761   DEFINE_CLASS_QUERY(FastUnlock)
 762   DEFINE_CLASS_QUERY(If)
 763   DEFINE_CLASS_QUERY(RangeCheck)
 764   DEFINE_CLASS_QUERY(IfFalse)
 765   DEFINE_CLASS_QUERY(IfTrue)
 766   DEFINE_CLASS_QUERY(Initialize)
 767   DEFINE_CLASS_QUERY(Jump)
 768   DEFINE_CLASS_QUERY(JumpProj)
 769   DEFINE_CLASS_QUERY(Load)
 770   DEFINE_CLASS_QUERY(LoadStore)
 771   DEFINE_CLASS_QUERY(Lock)
 772   DEFINE_CLASS_QUERY(Loop)
 773   DEFINE_CLASS_QUERY(Mach)
 774   DEFINE_CLASS_QUERY(MachBranch)
 775   DEFINE_CLASS_QUERY(MachCall)
 776   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 777   DEFINE_CLASS_QUERY(MachCallJava)
 778   DEFINE_CLASS_QUERY(MachCallLeaf)
 779   DEFINE_CLASS_QUERY(MachCallRuntime)
 780   DEFINE_CLASS_QUERY(MachCallStaticJava)
 781   DEFINE_CLASS_QUERY(MachConstantBase)
 782   DEFINE_CLASS_QUERY(MachConstant)
 783   DEFINE_CLASS_QUERY(MachGoto)
 784   DEFINE_CLASS_QUERY(MachIf)
 785   DEFINE_CLASS_QUERY(MachNullCheck)
 786   DEFINE_CLASS_QUERY(MachProj)
 787   DEFINE_CLASS_QUERY(MachReturn)
 788   DEFINE_CLASS_QUERY(MachSafePoint)
 789   DEFINE_CLASS_QUERY(MachSpillCopy)
 790   DEFINE_CLASS_QUERY(MachTemp)
 791   DEFINE_CLASS_QUERY(MachMerge)
 792   DEFINE_CLASS_QUERY(Mem)
 793   DEFINE_CLASS_QUERY(MemBar)
 794   DEFINE_CLASS_QUERY(MemBarStoreStore)
 795   DEFINE_CLASS_QUERY(MergeMem)
 796   DEFINE_CLASS_QUERY(Mul)
 797   DEFINE_CLASS_QUERY(Multi)
 798   DEFINE_CLASS_QUERY(MultiBranch)
 799   DEFINE_CLASS_QUERY(Parm)
 800   DEFINE_CLASS_QUERY(PCTable)
 801   DEFINE_CLASS_QUERY(Phi)
 802   DEFINE_CLASS_QUERY(Proj)
 803   DEFINE_CLASS_QUERY(Region)
 804   DEFINE_CLASS_QUERY(Root)
 805   DEFINE_CLASS_QUERY(SafePoint)
 806   DEFINE_CLASS_QUERY(SafePointScalarObject)
 807   DEFINE_CLASS_QUERY(Start)
 808   DEFINE_CLASS_QUERY(Store)
 809   DEFINE_CLASS_QUERY(Sub)
 810   DEFINE_CLASS_QUERY(Type)
 811   DEFINE_CLASS_QUERY(Vector)
 812   DEFINE_CLASS_QUERY(LoadVector)
 813   DEFINE_CLASS_QUERY(StoreVector)
 814   DEFINE_CLASS_QUERY(Unlock)
 815 
 816   #undef DEFINE_CLASS_QUERY
 817 
 818   // duplicate of is_MachSpillCopy()
 819   bool is_SpillCopy () const {
 820     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 821   }
 822 
 823   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 824   // The data node which is safe to leave in dead loop during IGVN optimization.
 825   bool is_dead_loop_safe() const {
 826     return is_Phi() || (is_Proj() && in(0) == NULL) ||
 827            ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0 &&
 828             (!is_Proj() || !in(0)->is_Allocate()));
 829   }
 830 
 831   // is_Copy() returns copied edge index (0 or 1)
 832   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 833 
 834   virtual bool is_CFG() const { return false; }
 835 
 836   // If this node is control-dependent on a test, can it be
 837   // rerouted to a dominating equivalent test?  This is usually
 838   // true of non-CFG nodes, but can be false for operations which
 839   // depend for their correct sequencing on more than one test.
 840   // (In that case, hoisting to a dominating test may silently
 841   // skip some other important test.)
 842   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 843 
 844   // When building basic blocks, I need to have a notion of block beginning
 845   // Nodes, next block selector Nodes (block enders), and next block
 846   // projections.  These calls need to work on their machine equivalents.  The
 847   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 848   bool is_block_start() const {
 849     if ( is_Region() )
 850       return this == (const Node*)in(0);
 851     else
 852       return is_Start();
 853   }
 854 
 855   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 856   // Goto and Return.  This call also returns the block ending Node.
 857   virtual const Node *is_block_proj() const;
 858 
 859   // The node is a "macro" node which needs to be expanded before matching
 860   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 861   // The node is expensive: the best control is set during loop opts
 862   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 863 
 864   // An arithmetic node which accumulates a data in a loop.
 865   // It must have the loop's phi as input and provide a def to the phi.
 866   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 867 
 868   // Used in lcm to mark nodes that have scheduled
 869   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
 870 
 871 //----------------- Optimization
 872 
 873   // Get the worst-case Type output for this Node.
 874   virtual const class Type *bottom_type() const;
 875 
 876   // If we find a better type for a node, try to record it permanently.
 877   // Return true if this node actually changed.
 878   // Be sure to do the hash_delete game in the "rehash" variant.
 879   void raise_bottom_type(const Type* new_type);
 880 
 881   // Get the address type with which this node uses and/or defs memory,
 882   // or NULL if none.  The address type is conservatively wide.
 883   // Returns non-null for calls, membars, loads, stores, etc.
 884   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
 885   virtual const class TypePtr *adr_type() const { return NULL; }
 886 
 887   // Return an existing node which computes the same function as this node.
 888   // The optimistic combined algorithm requires this to return a Node which
 889   // is a small number of steps away (e.g., one of my inputs).
 890   virtual Node *Identity( PhaseTransform *phase );
 891 
 892   // Return the set of values this Node can take on at runtime.
 893   virtual const Type *Value( PhaseTransform *phase ) const;
 894 
 895   // Return a node which is more "ideal" than the current node.
 896   // The invariants on this call are subtle.  If in doubt, read the
 897   // treatise in node.cpp above the default implemention AND TEST WITH
 898   // +VerifyIterativeGVN!
 899   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 900 
 901   // Some nodes have specific Ideal subgraph transformations only if they are
 902   // unique users of specific nodes. Such nodes should be put on IGVN worklist
 903   // for the transformations to happen.
 904   bool has_special_unique_user() const;
 905 
 906   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
 907   Node* find_exact_control(Node* ctrl);
 908 
 909   // Check if 'this' node dominates or equal to 'sub'.
 910   bool dominates(Node* sub, Node_List &nlist);
 911 
 912 protected:
 913   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
 914 public:
 915 
 916   // See if there is valid pipeline info
 917   static  const Pipeline *pipeline_class();
 918   virtual const Pipeline *pipeline() const;
 919 
 920   // Compute the latency from the def to this instruction of the ith input node
 921   uint latency(uint i);
 922 
 923   // Hash & compare functions, for pessimistic value numbering
 924 
 925   // If the hash function returns the special sentinel value NO_HASH,
 926   // the node is guaranteed never to compare equal to any other node.
 927   // If we accidentally generate a hash with value NO_HASH the node
 928   // won't go into the table and we'll lose a little optimization.
 929   enum { NO_HASH = 0 };
 930   virtual uint hash() const;
 931   virtual uint cmp( const Node &n ) const;
 932 
 933   // Operation appears to be iteratively computed (such as an induction variable)
 934   // It is possible for this operation to return false for a loop-varying
 935   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
 936   bool is_iteratively_computed();
 937 
 938   // Determine if a node is Counted loop induction variable.
 939   // The method is defined in loopnode.cpp.
 940   const Node* is_loop_iv() const;
 941 
 942   // Return a node with opcode "opc" and same inputs as "this" if one can
 943   // be found; Otherwise return NULL;
 944   Node* find_similar(int opc);
 945 
 946   // Return the unique control out if only one. Null if none or more than one.
 947   Node* unique_ctrl_out() const;
 948 
 949   // Set control or add control as precedence edge
 950   void ensure_control_or_add_prec(Node* c);
 951 
 952 //----------------- Code Generation
 953 
 954   // Ideal register class for Matching.  Zero means unmatched instruction
 955   // (these are cloned instead of converted to machine nodes).
 956   virtual uint ideal_reg() const;
 957 
 958   static const uint NotAMachineReg;   // must be > max. machine register
 959 
 960   // Do we Match on this edge index or not?  Generally false for Control
 961   // and true for everything else.  Weird for calls & returns.
 962   virtual uint match_edge(uint idx) const;
 963 
 964   // Register class output is returned in
 965   virtual const RegMask &out_RegMask() const;
 966   // Register class input is expected in
 967   virtual const RegMask &in_RegMask(uint) const;
 968   // Should we clone rather than spill this instruction?
 969   bool rematerialize() const;
 970 
 971   // Return JVM State Object if this Node carries debug info, or NULL otherwise
 972   virtual JVMState* jvms() const;
 973 
 974   // Print as assembly
 975   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
 976   // Emit bytes starting at parameter 'ptr'
 977   // Bump 'ptr' by the number of output bytes
 978   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
 979   // Size of instruction in bytes
 980   virtual uint size(PhaseRegAlloc *ra_) const;
 981 
 982   // Convenience function to extract an integer constant from a node.
 983   // If it is not an integer constant (either Con, CastII, or Mach),
 984   // return value_if_unknown.
 985   jint find_int_con(jint value_if_unknown) const {
 986     const TypeInt* t = find_int_type();
 987     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
 988   }
 989   // Return the constant, knowing it is an integer constant already
 990   jint get_int() const {
 991     const TypeInt* t = find_int_type();
 992     guarantee(t != NULL, "must be con");
 993     return t->get_con();
 994   }
 995   // Here's where the work is done.  Can produce non-constant int types too.
 996   const TypeInt* find_int_type() const;
 997 
 998   // Same thing for long (and intptr_t, via type.hpp):
 999   jlong get_long() const {
1000     const TypeLong* t = find_long_type();
1001     guarantee(t != NULL, "must be con");
1002     return t->get_con();
1003   }
1004   jlong find_long_con(jint value_if_unknown) const {
1005     const TypeLong* t = find_long_type();
1006     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1007   }
1008   const TypeLong* find_long_type() const;
1009 
1010   const TypePtr* get_ptr_type() const;
1011 
1012   // These guys are called by code generated by ADLC:
1013   intptr_t get_ptr() const;
1014   intptr_t get_narrowcon() const;
1015   jdouble getd() const;
1016   jfloat getf() const;
1017 
1018   // Nodes which are pinned into basic blocks
1019   virtual bool pinned() const { return false; }
1020 
1021   // Nodes which use memory without consuming it, hence need antidependences
1022   // More specifically, needs_anti_dependence_check returns true iff the node
1023   // (a) does a load, and (b) does not perform a store (except perhaps to a
1024   // stack slot or some other unaliased location).
1025   bool needs_anti_dependence_check() const;
1026 
1027   // Return which operand this instruction may cisc-spill. In other words,
1028   // return operand position that can convert from reg to memory access
1029   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1030   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1031 
1032 //----------------- Graph walking
1033 public:
1034   // Walk and apply member functions recursively.
1035   // Supplied (this) pointer is root.
1036   void walk(NFunc pre, NFunc post, void *env);
1037   static void nop(Node &, void*); // Dummy empty function
1038   static void packregion( Node &n, void* );
1039 private:
1040   void walk_(NFunc pre, NFunc post, void *env, VectorSet &visited);
1041 
1042 //----------------- Printing, etc
1043 public:
1044 #ifndef PRODUCT
1045   Node* find(int idx) const;         // Search the graph for the given idx.
1046   Node* find_ctrl(int idx) const;    // Search control ancestors for the given idx.
1047   void dump() const { dump("\n"); }  // Print this node.
1048   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1049   void dump(int depth) const;        // Print this node, recursively to depth d
1050   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1051   void dump_comp() const;            // Print this node in compact representation.
1052   // Print this node in compact representation.
1053   void dump_comp(const char* suffix, outputStream *st = tty) const;
1054   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1055   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1056   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1057   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1058   // Print compact per-node info
1059   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1060   void dump_related() const;             // Print related nodes (depends on node at hand).
1061   // Print related nodes up to given depths for input and output nodes.
1062   void dump_related(uint d_in, uint d_out) const;
1063   void dump_related_compact() const;     // Print related nodes in compact representation.
1064   // Collect related nodes.
1065   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1066   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1067   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1068 
1069   // Node collectors, to be used in implementations of Node::rel().
1070   // Collect the entire data input graph. Include control inputs if requested.
1071   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1072   // Collect the entire control input graph. Include data inputs if requested.
1073   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1074   // Collect the entire output graph until hitting and including control nodes.
1075   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1076 
1077   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1078   void verify() const;               // Check Def-Use info for my subgraph
1079   static void verify_recur(const Node *n, int verify_depth, VectorSet &old_space, VectorSet &new_space);
1080 
1081   // This call defines a class-unique string used to identify class instances
1082   virtual const char *Name() const;
1083 
1084   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1085   // RegMask Print Functions
1086   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1087   void dump_out_regmask() { out_RegMask().dump(); }
1088   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1089   void fast_dump() const {
1090     tty->print("%4d: %-17s", _idx, Name());
1091     for (uint i = 0; i < len(); i++)
1092       if (in(i))
1093         tty->print(" %4d", in(i)->_idx);
1094       else
1095         tty->print(" NULL");
1096     tty->print("\n");
1097   }
1098 #endif
1099 #ifdef ASSERT
1100   void verify_construction();
1101   bool verify_jvms(const JVMState* jvms) const;
1102   int  _debug_idx;                     // Unique value assigned to every node.
1103   int   debug_idx() const              { return _debug_idx; }
1104   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1105 
1106   Node* _debug_orig;                   // Original version of this, if any.
1107   Node*  debug_orig() const            { return _debug_orig; }
1108   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1109 
1110   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1111   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1112   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1113 
1114   static void init_NodeProperty();
1115 
1116   #if OPTO_DU_ITERATOR_ASSERT
1117   const Node* _last_del;               // The last deleted node.
1118   uint        _del_tick;               // Bumped when a deletion happens..
1119   #endif
1120 #endif
1121 };
1122 
1123 
1124 #ifndef PRODUCT
1125 
1126 // Used in debugging code to avoid walking across dead or uninitialized edges.
1127 inline bool NotANode(const Node* n) {
1128   if (n == NULL)                   return true;
1129   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1130   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1131   return false;
1132 }
1133 
1134 #endif
1135 
1136 
1137 //-----------------------------------------------------------------------------
1138 // Iterators over DU info, and associated Node functions.
1139 
1140 #if OPTO_DU_ITERATOR_ASSERT
1141 
1142 // Common code for assertion checking on DU iterators.
1143 class DUIterator_Common VALUE_OBJ_CLASS_SPEC {
1144 #ifdef ASSERT
1145  protected:
1146   bool         _vdui;               // cached value of VerifyDUIterators
1147   const Node*  _node;               // the node containing the _out array
1148   uint         _outcnt;             // cached node->_outcnt
1149   uint         _del_tick;           // cached node->_del_tick
1150   Node*        _last;               // last value produced by the iterator
1151 
1152   void sample(const Node* node);    // used by c'tor to set up for verifies
1153   void verify(const Node* node, bool at_end_ok = false);
1154   void verify_resync();
1155   void reset(const DUIterator_Common& that);
1156 
1157 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1158   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1159 #else
1160   #define I_VDUI_ONLY(i,x) { }
1161 #endif //ASSERT
1162 };
1163 
1164 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1165 
1166 // Default DU iterator.  Allows appends onto the out array.
1167 // Allows deletion from the out array only at the current point.
1168 // Usage:
1169 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1170 //    Node* y = x->out(i);
1171 //    ...
1172 //  }
1173 // Compiles in product mode to a unsigned integer index, which indexes
1174 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1175 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1176 // before continuing the loop.  You must delete only the last-produced
1177 // edge.  You must delete only a single copy of the last-produced edge,
1178 // or else you must delete all copies at once (the first time the edge
1179 // is produced by the iterator).
1180 class DUIterator : public DUIterator_Common {
1181   friend class Node;
1182 
1183   // This is the index which provides the product-mode behavior.
1184   // Whatever the product-mode version of the system does to the
1185   // DUI index is done to this index.  All other fields in
1186   // this class are used only for assertion checking.
1187   uint         _idx;
1188 
1189   #ifdef ASSERT
1190   uint         _refresh_tick;    // Records the refresh activity.
1191 
1192   void sample(const Node* node); // Initialize _refresh_tick etc.
1193   void verify(const Node* node, bool at_end_ok = false);
1194   void verify_increment();       // Verify an increment operation.
1195   void verify_resync();          // Verify that we can back up over a deletion.
1196   void verify_finish();          // Verify that the loop terminated properly.
1197   void refresh();                // Resample verification info.
1198   void reset(const DUIterator& that);  // Resample after assignment.
1199   #endif
1200 
1201   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1202     { _idx = 0;                         debug_only(sample(node)); }
1203 
1204  public:
1205   // initialize to garbage; clear _vdui to disable asserts
1206   DUIterator()
1207     { /*initialize to garbage*/         debug_only(_vdui = false); }
1208 
1209   void operator++(int dummy_to_specify_postfix_op)
1210     { _idx++;                           VDUI_ONLY(verify_increment()); }
1211 
1212   void operator--()
1213     { VDUI_ONLY(verify_resync());       --_idx; }
1214 
1215   ~DUIterator()
1216     { VDUI_ONLY(verify_finish()); }
1217 
1218   void operator=(const DUIterator& that)
1219     { _idx = that._idx;                 debug_only(reset(that)); }
1220 };
1221 
1222 DUIterator Node::outs() const
1223   { return DUIterator(this, 0); }
1224 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1225   { I_VDUI_ONLY(i, i.refresh());        return i; }
1226 bool Node::has_out(DUIterator& i) const
1227   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1228 Node*    Node::out(DUIterator& i) const
1229   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1230 
1231 
1232 // Faster DU iterator.  Disallows insertions into the out array.
1233 // Allows deletion from the out array only at the current point.
1234 // Usage:
1235 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1236 //    Node* y = x->fast_out(i);
1237 //    ...
1238 //  }
1239 // Compiles in product mode to raw Node** pointer arithmetic, with
1240 // no reloading of pointers from the original node x.  If you delete,
1241 // you must perform "--i; --imax" just before continuing the loop.
1242 // If you delete multiple copies of the same edge, you must decrement
1243 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1244 class DUIterator_Fast : public DUIterator_Common {
1245   friend class Node;
1246   friend class DUIterator_Last;
1247 
1248   // This is the pointer which provides the product-mode behavior.
1249   // Whatever the product-mode version of the system does to the
1250   // DUI pointer is done to this pointer.  All other fields in
1251   // this class are used only for assertion checking.
1252   Node**       _outp;
1253 
1254   #ifdef ASSERT
1255   void verify(const Node* node, bool at_end_ok = false);
1256   void verify_limit();
1257   void verify_resync();
1258   void verify_relimit(uint n);
1259   void reset(const DUIterator_Fast& that);
1260   #endif
1261 
1262   // Note:  offset must be signed, since -1 is sometimes passed
1263   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1264     { _outp = node->_out + offset;      debug_only(sample(node)); }
1265 
1266  public:
1267   // initialize to garbage; clear _vdui to disable asserts
1268   DUIterator_Fast()
1269     { /*initialize to garbage*/         debug_only(_vdui = false); }
1270 
1271   void operator++(int dummy_to_specify_postfix_op)
1272     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1273 
1274   void operator--()
1275     { VDUI_ONLY(verify_resync());       --_outp; }
1276 
1277   void operator-=(uint n)   // applied to the limit only
1278     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1279 
1280   bool operator<(DUIterator_Fast& limit) {
1281     I_VDUI_ONLY(*this, this->verify(_node, true));
1282     I_VDUI_ONLY(limit, limit.verify_limit());
1283     return _outp < limit._outp;
1284   }
1285 
1286   void operator=(const DUIterator_Fast& that)
1287     { _outp = that._outp;               debug_only(reset(that)); }
1288 };
1289 
1290 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1291   // Assign a limit pointer to the reference argument:
1292   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1293   // Return the base pointer:
1294   return DUIterator_Fast(this, 0);
1295 }
1296 Node* Node::fast_out(DUIterator_Fast& i) const {
1297   I_VDUI_ONLY(i, i.verify(this));
1298   return debug_only(i._last=) *i._outp;
1299 }
1300 
1301 
1302 // Faster DU iterator.  Requires each successive edge to be removed.
1303 // Does not allow insertion of any edges.
1304 // Usage:
1305 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1306 //    Node* y = x->last_out(i);
1307 //    ...
1308 //  }
1309 // Compiles in product mode to raw Node** pointer arithmetic, with
1310 // no reloading of pointers from the original node x.
1311 class DUIterator_Last : private DUIterator_Fast {
1312   friend class Node;
1313 
1314   #ifdef ASSERT
1315   void verify(const Node* node, bool at_end_ok = false);
1316   void verify_limit();
1317   void verify_step(uint num_edges);
1318   #endif
1319 
1320   // Note:  offset must be signed, since -1 is sometimes passed
1321   DUIterator_Last(const Node* node, ptrdiff_t offset)
1322     : DUIterator_Fast(node, offset) { }
1323 
1324   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1325   void operator<(int)                              {} // do not use
1326 
1327  public:
1328   DUIterator_Last() { }
1329   // initialize to garbage
1330 
1331   void operator--()
1332     { _outp--;              VDUI_ONLY(verify_step(1));  }
1333 
1334   void operator-=(uint n)
1335     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1336 
1337   bool operator>=(DUIterator_Last& limit) {
1338     I_VDUI_ONLY(*this, this->verify(_node, true));
1339     I_VDUI_ONLY(limit, limit.verify_limit());
1340     return _outp >= limit._outp;
1341   }
1342 
1343   void operator=(const DUIterator_Last& that)
1344     { DUIterator_Fast::operator=(that); }
1345 };
1346 
1347 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1348   // Assign a limit pointer to the reference argument:
1349   imin = DUIterator_Last(this, 0);
1350   // Return the initial pointer:
1351   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1352 }
1353 Node* Node::last_out(DUIterator_Last& i) const {
1354   I_VDUI_ONLY(i, i.verify(this));
1355   return debug_only(i._last=) *i._outp;
1356 }
1357 
1358 #endif //OPTO_DU_ITERATOR_ASSERT
1359 
1360 #undef I_VDUI_ONLY
1361 #undef VDUI_ONLY
1362 
1363 // An Iterator that truly follows the iterator pattern.  Doesn't
1364 // support deletion but could be made to.
1365 //
1366 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1367 //     Node* m = i.get();
1368 //
1369 class SimpleDUIterator : public StackObj {
1370  private:
1371   Node* node;
1372   DUIterator_Fast i;
1373   DUIterator_Fast imax;
1374  public:
1375   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1376   bool has_next() { return i < imax; }
1377   void next() { i++; }
1378   Node* get() { return node->fast_out(i); }
1379 };
1380 
1381 
1382 //-----------------------------------------------------------------------------
1383 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1384 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1385 // Note that the constructor just zeros things, and since I use Arena
1386 // allocation I do not need a destructor to reclaim storage.
1387 class Node_Array : public ResourceObj {
1388   friend class VMStructs;
1389 protected:
1390   Arena *_a;                    // Arena to allocate in
1391   uint   _max;
1392   Node **_nodes;
1393   void   grow( uint i );        // Grow array node to fit
1394 public:
1395   Node_Array(Arena *a) : _a(a), _max(OptoNodeListSize) {
1396     _nodes = NEW_ARENA_ARRAY( a, Node *, OptoNodeListSize );
1397     for( int i = 0; i < OptoNodeListSize; i++ ) {
1398       _nodes[i] = NULL;
1399     }
1400   }
1401 
1402   Node_Array(Node_Array *na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1403   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1404   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1405   Node *at( uint i ) const { assert(i<_max,"oob"); return _nodes[i]; }
1406   Node **adr() { return _nodes; }
1407   // Extend the mapping: index i maps to Node *n.
1408   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1409   void insert( uint i, Node *n );
1410   void remove( uint i );        // Remove, preserving order
1411   void sort( C_sort_func_t func);
1412   void reset( Arena *new_a );   // Zap mapping to empty; reclaim storage
1413   void clear();                 // Set all entries to NULL, keep storage
1414   uint Size() const { return _max; }
1415   void dump() const;
1416 };
1417 
1418 class Node_List : public Node_Array {
1419   friend class VMStructs;
1420   uint _cnt;
1421 public:
1422   Node_List() : Node_Array(Thread::current()->resource_area()), _cnt(0) {}
1423   Node_List(Arena *a) : Node_Array(a), _cnt(0) {}
1424   bool contains(const Node* n) const {
1425     for (uint e = 0; e < size(); e++) {
1426       if (at(e) == n) return true;
1427     }
1428     return false;
1429   }
1430   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1431   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1432   void push( Node *b ) { map(_cnt++,b); }
1433   void yank( Node *n );         // Find and remove
1434   Node *pop() { return _nodes[--_cnt]; }
1435   Node *rpop() { Node *b = _nodes[0]; _nodes[0]=_nodes[--_cnt]; return b;}
1436   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1437   uint size() const { return _cnt; }
1438   void dump() const;
1439 };
1440 
1441 //------------------------------Unique_Node_List-------------------------------
1442 class Unique_Node_List : public Node_List {
1443   friend class VMStructs;
1444   VectorSet _in_worklist;
1445   uint _clock_index;            // Index in list where to pop from next
1446 public:
1447   Unique_Node_List() : Node_List(), _in_worklist(Thread::current()->resource_area()), _clock_index(0) {}
1448   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1449 
1450   void remove( Node *n );
1451   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1452   VectorSet &member_set(){ return _in_worklist; }
1453 
1454   void push( Node *b ) {
1455     if( !_in_worklist.test_set(b->_idx) )
1456       Node_List::push(b);
1457   }
1458   Node *pop() {
1459     if( _clock_index >= size() ) _clock_index = 0;
1460     Node *b = at(_clock_index);
1461     map( _clock_index, Node_List::pop());
1462     if (size() != 0) _clock_index++; // Always start from 0
1463     _in_worklist >>= b->_idx;
1464     return b;
1465   }
1466   Node *remove( uint i ) {
1467     Node *b = Node_List::at(i);
1468     _in_worklist >>= b->_idx;
1469     map(i,Node_List::pop());
1470     return b;
1471   }
1472   void yank( Node *n ) { _in_worklist >>= n->_idx; Node_List::yank(n); }
1473   void  clear() {
1474     _in_worklist.Clear();        // Discards storage but grows automatically
1475     Node_List::clear();
1476     _clock_index = 0;
1477   }
1478 
1479   // Used after parsing to remove useless nodes before Iterative GVN
1480   void remove_useless_nodes(VectorSet &useful);
1481 
1482 #ifndef PRODUCT
1483   void print_set() const { _in_worklist.print(); }
1484 #endif
1485 };
1486 
1487 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1488 inline void Compile::record_for_igvn(Node* n) {
1489   _for_igvn->push(n);
1490 }
1491 
1492 //------------------------------Node_Stack-------------------------------------
1493 class Node_Stack {
1494   friend class VMStructs;
1495 protected:
1496   struct INode {
1497     Node *node; // Processed node
1498     uint  indx; // Index of next node's child
1499   };
1500   INode *_inode_top; // tos, stack grows up
1501   INode *_inode_max; // End of _inodes == _inodes + _max
1502   INode *_inodes;    // Array storage for the stack
1503   Arena *_a;         // Arena to allocate in
1504   void grow();
1505 public:
1506   Node_Stack(int size) {
1507     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1508     _a = Thread::current()->resource_area();
1509     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1510     _inode_max = _inodes + max;
1511     _inode_top = _inodes - 1; // stack is empty
1512   }
1513 
1514   Node_Stack(Arena *a, int size) : _a(a) {
1515     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1516     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1517     _inode_max = _inodes + max;
1518     _inode_top = _inodes - 1; // stack is empty
1519   }
1520 
1521   void pop() {
1522     assert(_inode_top >= _inodes, "node stack underflow");
1523     --_inode_top;
1524   }
1525   void push(Node *n, uint i) {
1526     ++_inode_top;
1527     if (_inode_top >= _inode_max) grow();
1528     INode *top = _inode_top; // optimization
1529     top->node = n;
1530     top->indx = i;
1531   }
1532   Node *node() const {
1533     return _inode_top->node;
1534   }
1535   Node* node_at(uint i) const {
1536     assert(_inodes + i <= _inode_top, "in range");
1537     return _inodes[i].node;
1538   }
1539   uint index() const {
1540     return _inode_top->indx;
1541   }
1542   uint index_at(uint i) const {
1543     assert(_inodes + i <= _inode_top, "in range");
1544     return _inodes[i].indx;
1545   }
1546   void set_node(Node *n) {
1547     _inode_top->node = n;
1548   }
1549   void set_index(uint i) {
1550     _inode_top->indx = i;
1551   }
1552   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1553   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1554   bool is_nonempty() const { return (_inode_top >= _inodes); }
1555   bool is_empty() const { return (_inode_top < _inodes); }
1556   void clear() { _inode_top = _inodes - 1; } // retain storage
1557 
1558   // Node_Stack is used to map nodes.
1559   Node* find(uint idx) const;
1560 };
1561 
1562 
1563 //-----------------------------Node_Notes--------------------------------------
1564 // Debugging or profiling annotations loosely and sparsely associated
1565 // with some nodes.  See Compile::node_notes_at for the accessor.
1566 class Node_Notes VALUE_OBJ_CLASS_SPEC {
1567   friend class VMStructs;
1568   JVMState* _jvms;
1569 
1570 public:
1571   Node_Notes(JVMState* jvms = NULL) {
1572     _jvms = jvms;
1573   }
1574 
1575   JVMState* jvms()            { return _jvms; }
1576   void  set_jvms(JVMState* x) {        _jvms = x; }
1577 
1578   // True if there is nothing here.
1579   bool is_clear() {
1580     return (_jvms == NULL);
1581   }
1582 
1583   // Make there be nothing here.
1584   void clear() {
1585     _jvms = NULL;
1586   }
1587 
1588   // Make a new, clean node notes.
1589   static Node_Notes* make(Compile* C) {
1590     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1591     nn->clear();
1592     return nn;
1593   }
1594 
1595   Node_Notes* clone(Compile* C) {
1596     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1597     (*nn) = (*this);
1598     return nn;
1599   }
1600 
1601   // Absorb any information from source.
1602   bool update_from(Node_Notes* source) {
1603     bool changed = false;
1604     if (source != NULL) {
1605       if (source->jvms() != NULL) {
1606         set_jvms(source->jvms());
1607         changed = true;
1608       }
1609     }
1610     return changed;
1611   }
1612 };
1613 
1614 // Inlined accessors for Compile::node_nodes that require the preceding class:
1615 inline Node_Notes*
1616 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1617                            int idx, bool can_grow) {
1618   assert(idx >= 0, "oob");
1619   int block_idx = (idx >> _log2_node_notes_block_size);
1620   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1621   if (grow_by >= 0) {
1622     if (!can_grow)  return NULL;
1623     grow_node_notes(arr, grow_by + 1);
1624   }
1625   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1626   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1627 }
1628 
1629 inline bool
1630 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1631   if (value == NULL || value->is_clear())
1632     return false;  // nothing to write => write nothing
1633   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1634   assert(loc != NULL, "");
1635   return loc->update_from(value);
1636 }
1637 
1638 
1639 //------------------------------TypeNode---------------------------------------
1640 // Node with a Type constant.
1641 class TypeNode : public Node {
1642 protected:
1643   virtual uint hash() const;    // Check the type
1644   virtual uint cmp( const Node &n ) const;
1645   virtual uint size_of() const; // Size is bigger
1646   const Type* const _type;
1647 public:
1648   void set_type(const Type* t) {
1649     assert(t != NULL, "sanity");
1650     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1651     *(const Type**)&_type = t;   // cast away const-ness
1652     // If this node is in the hash table, make sure it doesn't need a rehash.
1653     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1654   }
1655   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1656   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1657     init_class_id(Class_Type);
1658   }
1659   virtual const Type *Value( PhaseTransform *phase ) const;
1660   virtual const Type *bottom_type() const;
1661   virtual       uint  ideal_reg() const;
1662 #ifndef PRODUCT
1663   virtual void dump_spec(outputStream *st) const;
1664   virtual void dump_compact_spec(outputStream *st) const;
1665 #endif
1666 };
1667 
1668 #endif // SHARE_VM_OPTO_NODE_HPP