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