1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_NODE_HPP
  26 #define SHARE_VM_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 
  32 // Portions of code courtesy of Clifford Click
  33 
  34 // Optimization - Graph Style
  35 
  36 
  37 class AbstractLockNode;
  38 class AddNode;
  39 class AddPNode;
  40 class AliasInfo;
  41 class AllocateArrayNode;
  42 class AllocateNode;
  43 class ArrayCopyNode;
  44 class Block;
  45 class BoolNode;
  46 class BoxLockNode;
  47 class CMoveNode;
  48 class CallDynamicJavaNode;
  49 class CallJavaNode;
  50 class CallLeafNode;
  51 class CallNode;
  52 class CallRuntimeNode;
  53 class CallStaticJavaNode;
  54 class CastIINode;
  55 class CatchNode;
  56 class CatchProjNode;
  57 class CheckCastPPNode;
  58 class ClearArrayNode;
  59 class CmpNode;
  60 class CodeBuffer;
  61 class ConstraintCastNode;
  62 class ConNode;
  63 class CompareAndSwapNode;
  64 class CompareAndExchangeNode;
  65 class CountedLoopNode;
  66 class CountedLoopEndNode;
  67 class DecodeNarrowPtrNode;
  68 class DecodeNNode;
  69 class DecodeNKlassNode;
  70 class EncodeNarrowPtrNode;
  71 class EncodePNode;
  72 class EncodePKlassNode;
  73 class FastLockNode;
  74 class FastUnlockNode;
  75 class IfNode;
  76 class IfFalseNode;
  77 class IfTrueNode;
  78 class InitializeNode;
  79 class JVMState;
  80 class JumpNode;
  81 class JumpProjNode;
  82 class LoadNode;
  83 class LoadStoreNode;
  84 class LockNode;
  85 class LoopNode;
  86 class MachBranchNode;
  87 class MachCallDynamicJavaNode;
  88 class MachCallJavaNode;
  89 class MachCallLeafNode;
  90 class MachCallNode;
  91 class MachCallRuntimeNode;
  92 class MachCallStaticJavaNode;
  93 class MachConstantBaseNode;
  94 class MachConstantNode;
  95 class MachGotoNode;
  96 class MachIfNode;
  97 class MachNode;
  98 class MachNullCheckNode;
  99 class MachProjNode;
 100 class MachReturnNode;
 101 class MachSafePointNode;
 102 class MachSpillCopyNode;
 103 class MachTempNode;
 104 class MachMergeNode;
 105 class Matcher;
 106 class MemBarNode;
 107 class MemBarStoreStoreNode;
 108 class MemNode;
 109 class MergeMemNode;
 110 class MulNode;
 111 class MultiNode;
 112 class MultiBranchNode;
 113 class NeverBranchNode;
 114 class Node;
 115 class Node_Array;
 116 class Node_List;
 117 class Node_Stack;
 118 class NullCheckNode;
 119 class OopMap;
 120 class ParmNode;
 121 class PCTableNode;
 122 class PhaseCCP;
 123 class PhaseGVN;
 124 class PhaseIterGVN;
 125 class PhaseRegAlloc;
 126 class PhaseTransform;
 127 class PhaseValues;
 128 class PhiNode;
 129 class Pipeline;
 130 class ProjNode;
 131 class RangeCheckNode;
 132 class RegMask;
 133 class RegionNode;
 134 class RootNode;
 135 class SafePointNode;
 136 class SafePointScalarObjectNode;
 137 class StartNode;
 138 class State;
 139 class StoreNode;
 140 class SubNode;
 141 class Type;
 142 class TypeNode;
 143 class UnlockNode;
 144 class VectorNode;
 145 class LoadVectorNode;
 146 class StoreVectorNode;
 147 class VectorSet;
 148 typedef void (*NFunc)(Node&,void*);
 149 extern "C" {
 150   typedef int (*C_sort_func_t)(const void *, const void *);
 151 }
 152 
 153 // The type of all node counts and indexes.
 154 // It must hold at least 16 bits, but must also be fast to load and store.
 155 // This type, if less than 32 bits, could limit the number of possible nodes.
 156 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 157 typedef unsigned int node_idx_t;
 158 
 159 
 160 #ifndef OPTO_DU_ITERATOR_ASSERT
 161 #ifdef ASSERT
 162 #define OPTO_DU_ITERATOR_ASSERT 1
 163 #else
 164 #define OPTO_DU_ITERATOR_ASSERT 0
 165 #endif
 166 #endif //OPTO_DU_ITERATOR_ASSERT
 167 
 168 #if OPTO_DU_ITERATOR_ASSERT
 169 class DUIterator;
 170 class DUIterator_Fast;
 171 class DUIterator_Last;
 172 #else
 173 typedef uint   DUIterator;
 174 typedef Node** DUIterator_Fast;
 175 typedef Node** DUIterator_Last;
 176 #endif
 177 
 178 // Node Sentinel
 179 #define NodeSentinel (Node*)-1
 180 
 181 // Unknown count frequency
 182 #define COUNT_UNKNOWN (-1.0f)
 183 
 184 //------------------------------Node-------------------------------------------
 185 // Nodes define actions in the program.  They create values, which have types.
 186 // They are both vertices in a directed graph and program primitives.  Nodes
 187 // are labeled; the label is the "opcode", the primitive function in the lambda
 188 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 189 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 190 // the Node's function.  These inputs also define a Type equation for the Node.
 191 // Solving these Type equations amounts to doing dataflow analysis.
 192 // Control and data are uniformly represented in the graph.  Finally, Nodes
 193 // have a unique dense integer index which is used to index into side arrays
 194 // whenever I have phase-specific information.
 195 
 196 class Node {
 197   friend class VMStructs;
 198 
 199   // Lots of restrictions on cloning Nodes
 200   Node(const Node&);            // not defined; linker error to use these
 201   Node &operator=(const Node &rhs);
 202 
 203 public:
 204   friend class Compile;
 205   #if OPTO_DU_ITERATOR_ASSERT
 206   friend class DUIterator_Common;
 207   friend class DUIterator;
 208   friend class DUIterator_Fast;
 209   friend class DUIterator_Last;
 210   #endif
 211 
 212   // Because Nodes come and go, I define an Arena of Node structures to pull
 213   // from.  This should allow fast access to node creation & deletion.  This
 214   // field is a local cache of a value defined in some "program fragment" for
 215   // which these Nodes are just a part of.
 216 
 217   inline void* operator new(size_t x) throw() {
 218     Compile* C = Compile::current();
 219     Node* n = (Node*)C->node_arena()->Amalloc_D(x);
 220 #ifdef ASSERT
 221     n->_in = (Node**)n; // magic cookie for assertion check
 222 #endif
 223     return (void*)n;
 224   }
 225 
 226   // Delete is a NOP
 227   void operator delete( void *ptr ) {}
 228   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 229   void destruct();
 230 
 231   // Create a new Node.  Required is the number is of inputs required for
 232   // semantic correctness.
 233   Node( uint required );
 234 
 235   // Create a new Node with given input edges.
 236   // This version requires use of the "edge-count" new.
 237   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 238   Node( Node *n0 );
 239   Node( Node *n0, Node *n1 );
 240   Node( Node *n0, Node *n1, Node *n2 );
 241   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 242   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 243   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 244   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 245             Node *n4, Node *n5, Node *n6 );
 246 
 247   // Clone an inherited Node given only the base Node type.
 248   Node* clone() const;
 249 
 250   // Clone a Node, immediately supplying one or two new edges.
 251   // The first and second arguments, if non-null, replace in(1) and in(2),
 252   // respectively.
 253   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 254     Node* nn = clone();
 255     if (in1 != NULL)  nn->set_req(1, in1);
 256     if (in2 != NULL)  nn->set_req(2, in2);
 257     return nn;
 258   }
 259 
 260 private:
 261   // Shared setup for the above constructors.
 262   // Handles all interactions with Compile::current.
 263   // Puts initial values in all Node fields except _idx.
 264   // Returns the initial value for _idx, which cannot
 265   // be initialized by assignment.
 266   inline int Init(int req);
 267 
 268 //----------------- input edge handling
 269 protected:
 270   friend class PhaseCFG;        // Access to address of _in array elements
 271   Node **_in;                   // Array of use-def references to Nodes
 272   Node **_out;                  // Array of def-use references to Nodes
 273 
 274   // Input edges are split into two categories.  Required edges are required
 275   // for semantic correctness; order is important and NULLs are allowed.
 276   // Precedence edges are used to help determine execution order and are
 277   // added, e.g., for scheduling purposes.  They are unordered and not
 278   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 279   // are required, from _cnt to _max-1 are precedence edges.
 280   node_idx_t _cnt;              // Total number of required Node inputs.
 281 
 282   node_idx_t _max;              // Actual length of input array.
 283 
 284   // Output edges are an unordered list of def-use edges which exactly
 285   // correspond to required input edges which point from other nodes
 286   // to this one.  Thus the count of the output edges is the number of
 287   // users of this node.
 288   node_idx_t _outcnt;           // Total number of Node outputs.
 289 
 290   node_idx_t _outmax;           // Actual length of output array.
 291 
 292   // Grow the actual input array to the next larger power-of-2 bigger than len.
 293   void grow( uint len );
 294   // Grow the output array to the next larger power-of-2 bigger than len.
 295   void out_grow( uint len );
 296 
 297  public:
 298   // Each Node is assigned a unique small/dense number.  This number is used
 299   // to index into auxiliary arrays of data and bit vectors.
 300   // The field _idx is declared constant to defend against inadvertent assignments,
 301   // since it is used by clients as a naked field. However, the field's value can be
 302   // changed using the set_idx() method.
 303   //
 304   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 305   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 306   // preserved in _parse_idx.
 307   const node_idx_t _idx;
 308   DEBUG_ONLY(const node_idx_t _parse_idx;)
 309 
 310   // Get the (read-only) number of input edges
 311   uint req() const { return _cnt; }
 312   uint len() const { return _max; }
 313   // Get the (read-only) number of output edges
 314   uint outcnt() const { return _outcnt; }
 315 
 316 #if OPTO_DU_ITERATOR_ASSERT
 317   // Iterate over the out-edges of this node.  Deletions are illegal.
 318   inline DUIterator outs() const;
 319   // Use this when the out array might have changed to suppress asserts.
 320   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 321   // Does the node have an out at this position?  (Used for iteration.)
 322   inline bool has_out(DUIterator& i) const;
 323   inline Node*    out(DUIterator& i) const;
 324   // Iterate over the out-edges of this node.  All changes are illegal.
 325   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 326   inline Node*    fast_out(DUIterator_Fast& i) const;
 327   // Iterate over the out-edges of this node, deleting one at a time.
 328   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 329   inline Node*    last_out(DUIterator_Last& i) const;
 330   // The inline bodies of all these methods are after the iterator definitions.
 331 #else
 332   // Iterate over the out-edges of this node.  Deletions are illegal.
 333   // This iteration uses integral indexes, to decouple from array reallocations.
 334   DUIterator outs() const  { return 0; }
 335   // Use this when the out array might have changed to suppress asserts.
 336   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 337 
 338   // Reference to the i'th output Node.  Error if out of bounds.
 339   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 340   // Does the node have an out at this position?  (Used for iteration.)
 341   bool has_out(DUIterator i) const { return i < _outcnt; }
 342 
 343   // Iterate over the out-edges of this node.  All changes are illegal.
 344   // This iteration uses a pointer internal to the out array.
 345   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 346     Node** out = _out;
 347     // Assign a limit pointer to the reference argument:
 348     max = out + (ptrdiff_t)_outcnt;
 349     // Return the base pointer:
 350     return out;
 351   }
 352   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 353   // Iterate over the out-edges of this node, deleting one at a time.
 354   // This iteration uses a pointer internal to the out array.
 355   DUIterator_Last last_outs(DUIterator_Last& min) const {
 356     Node** out = _out;
 357     // Assign a limit pointer to the reference argument:
 358     min = out;
 359     // Return the pointer to the start of the iteration:
 360     return out + (ptrdiff_t)_outcnt - 1;
 361   }
 362   Node*    last_out(DUIterator_Last i) const  { return *i; }
 363 #endif
 364 
 365   // Reference to the i'th input Node.  Error if out of bounds.
 366   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 367   // Reference to the i'th input Node.  NULL if out of bounds.
 368   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 369   // Reference to the i'th output Node.  Error if out of bounds.
 370   // Use this accessor sparingly.  We are going trying to use iterators instead.
 371   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 372   // Return the unique out edge.
 373   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 374   // Delete out edge at position 'i' by moving last out edge to position 'i'
 375   void  raw_del_out(uint i) {
 376     assert(i < _outcnt,"oob");
 377     assert(_outcnt > 0,"oob");
 378     #if OPTO_DU_ITERATOR_ASSERT
 379     // Record that a change happened here.
 380     debug_only(_last_del = _out[i]; ++_del_tick);
 381     #endif
 382     _out[i] = _out[--_outcnt];
 383     // Smash the old edge so it can't be used accidentally.
 384     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 385   }
 386 
 387 #ifdef ASSERT
 388   bool is_dead() const;
 389 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 390 #endif
 391   // Check whether node has become unreachable
 392   bool is_unreachable(PhaseIterGVN &igvn) const;
 393 
 394   // Set a required input edge, also updates corresponding output edge
 395   void add_req( Node *n ); // Append a NEW required input
 396   void add_req( Node *n0, Node *n1 ) {
 397     add_req(n0); add_req(n1); }
 398   void add_req( Node *n0, Node *n1, Node *n2 ) {
 399     add_req(n0); add_req(n1); add_req(n2); }
 400   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 401   void del_req( uint idx ); // Delete required edge & compact
 402   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 403   void ins_req( uint i, Node *n ); // Insert a NEW required input
 404   void set_req( uint i, Node *n ) {
 405     assert( is_not_dead(n), "can not use dead node");
 406     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 407     assert( !VerifyHashTableKeys || _hash_lock == 0,
 408             "remove node from hash table before modifying it");
 409     Node** p = &_in[i];    // cache this._in, across the del_out call
 410     if (*p != NULL)  (*p)->del_out((Node *)this);
 411     (*p) = n;
 412     if (n != NULL)      n->add_out((Node *)this);
 413     Compile::current()->record_modified_node(this);
 414   }
 415   // Light version of set_req() to init inputs after node creation.
 416   void init_req( uint i, Node *n ) {
 417     assert( i == 0 && this == n ||
 418             is_not_dead(n), "can not use dead node");
 419     assert( i < _cnt, "oob");
 420     assert( !VerifyHashTableKeys || _hash_lock == 0,
 421             "remove node from hash table before modifying it");
 422     assert( _in[i] == NULL, "sanity");
 423     _in[i] = n;
 424     if (n != NULL)      n->add_out((Node *)this);
 425     Compile::current()->record_modified_node(this);
 426   }
 427   // Find first occurrence of n among my edges:
 428   int find_edge(Node* n);
 429   int find_prec_edge(Node* n) {
 430     for (uint i = req(); i < len(); i++) {
 431       if (_in[i] == n) return i;
 432       if (_in[i] == NULL) {
 433         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 434         break;
 435       }
 436     }
 437     return -1;
 438   }
 439   int replace_edge(Node* old, Node* neww);
 440   int replace_edges_in_range(Node* old, Node* neww, int start, int end);
 441   // NULL out all inputs to eliminate incoming Def-Use edges.
 442   // Return the number of edges between 'n' and 'this'
 443   int  disconnect_inputs(Node *n, Compile *c);
 444 
 445   // Quickly, return true if and only if I am Compile::current()->top().
 446   bool is_top() const {
 447     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 448     return (_out == NULL);
 449   }
 450   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 451   void setup_is_top();
 452 
 453   // Strip away casting.  (It is depth-limited.)
 454   Node* uncast() const;
 455   // Return whether two Nodes are equivalent, after stripping casting.
 456   bool eqv_uncast(const Node* n) const {
 457     return (this->uncast() == n->uncast());
 458   }
 459 
 460   // Find out of current node that matches opcode.
 461   Node* find_out_with(uint opcode);
 462   // Return true if the current node has an out that matches opcode.
 463   bool has_out_with(uint opcode);
 464   // Return true if the current node has an out that matches any of the opcodes.
 465   bool has_out_with(uint opcode1, uint opcode2, uint opcode3, uint opcode4);
 466 
 467 private:
 468   static Node* uncast_helper(const Node* n);
 469 
 470   // Add an output edge to the end of the list
 471   void add_out( Node *n ) {
 472     if (is_top())  return;
 473     if( _outcnt == _outmax ) out_grow(_outcnt);
 474     _out[_outcnt++] = n;
 475   }
 476   // Delete an output edge
 477   void del_out( Node *n ) {
 478     if (is_top())  return;
 479     Node** outp = &_out[_outcnt];
 480     // Find and remove n
 481     do {
 482       assert(outp > _out, "Missing Def-Use edge");
 483     } while (*--outp != n);
 484     *outp = _out[--_outcnt];
 485     // Smash the old edge so it can't be used accidentally.
 486     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 487     // Record that a change happened here.
 488     #if OPTO_DU_ITERATOR_ASSERT
 489     debug_only(_last_del = n; ++_del_tick);
 490     #endif
 491   }
 492   // Close gap after removing edge.
 493   void close_prec_gap_at(uint gap) {
 494     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 495     uint i = gap;
 496     Node *last = NULL;
 497     for (; i < _max-1; ++i) {
 498       Node *next = _in[i+1];
 499       if (next == NULL) break;
 500       last = next;
 501     }
 502     _in[gap] = last; // Move last slot to empty one.
 503     _in[i] = NULL;   // NULL out last slot.
 504   }
 505 
 506 public:
 507   // Globally replace this node by a given new node, updating all uses.
 508   void replace_by(Node* new_node);
 509   // Globally replace this node by a given new node, updating all uses
 510   // and cutting input edges of old node.
 511   void subsume_by(Node* new_node, Compile* c) {
 512     replace_by(new_node);
 513     disconnect_inputs(NULL, c);
 514   }
 515   void set_req_X( uint i, Node *n, PhaseIterGVN *igvn );
 516   // Find the one non-null required input.  RegionNode only
 517   Node *nonnull_req() const;
 518   // Add or remove precedence edges
 519   void add_prec( Node *n );
 520   void rm_prec( uint i );
 521 
 522   // Note: prec(i) will not necessarily point to n if edge already exists.
 523   void set_prec( uint i, Node *n ) {
 524     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 525     assert(is_not_dead(n), "can not use dead node");
 526     assert(i >= _cnt, "not a precedence edge");
 527     // Avoid spec violation: duplicated prec edge.
 528     if (_in[i] == n) return;
 529     if (n == NULL || find_prec_edge(n) != -1) {
 530       rm_prec(i);
 531       return;
 532     }
 533     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 534     _in[i] = n;
 535     if (n != NULL) n->add_out((Node *)this);
 536   }
 537 
 538   // Set this node's index, used by cisc_version to replace current node
 539   void set_idx(uint new_idx) {
 540     const node_idx_t* ref = &_idx;
 541     *(node_idx_t*)ref = new_idx;
 542   }
 543   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 544   void swap_edges(uint i1, uint i2) {
 545     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 546     // Def-Use info is unchanged
 547     Node* n1 = in(i1);
 548     Node* n2 = in(i2);
 549     _in[i1] = n2;
 550     _in[i2] = n1;
 551     // If this node is in the hash table, make sure it doesn't need a rehash.
 552     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 553   }
 554 
 555   // Iterators over input Nodes for a Node X are written as:
 556   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 557   // NOTE: Required edges can contain embedded NULL pointers.
 558 
 559 //----------------- Other Node Properties
 560 
 561   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 562   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 563   //
 564   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 565   // the type of the node the ID represents; another subset of an ID's bits are reserved
 566   // for the superclasses of the node represented by the ID.
 567   //
 568   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 569   // returns false. A.is_A() returns true.
 570   //
 571   // If two classes, A and B, have the same superclass, a different bit of A's class id
 572   // is reserved for A's type than for B's type. That bit is specified by the third
 573   // parameter in the macro DEFINE_CLASS_ID.
 574   //
 575   // By convention, classes with deeper hierarchy are declared first. Moreover,
 576   // classes with the same hierarchy depth are sorted by usage frequency.
 577   //
 578   // The query method masks the bits to cut off bits of subclasses and then compares
 579   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 580   //
 581   //  Class_MachCall=30, ClassMask_MachCall=31
 582   // 12               8               4               0
 583   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 584   //                                  |   |   |   |
 585   //                                  |   |   |   Bit_Mach=2
 586   //                                  |   |   Bit_MachReturn=4
 587   //                                  |   Bit_MachSafePoint=8
 588   //                                  Bit_MachCall=16
 589   //
 590   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 591   // 12               8               4               0
 592   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 593   //                              |   |   |
 594   //                              |   |   Bit_Region=8
 595   //                              |   Bit_Loop=16
 596   //                              Bit_CountedLoop=32
 597 
 598   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 599   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 600   Class_##cl = Class_##supcl + Bit_##cl , \
 601   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 602 
 603   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 604   // so that it's values fits into 16 bits.
 605   enum NodeClasses {
 606     Bit_Node   = 0x0000,
 607     Class_Node = 0x0000,
 608     ClassMask_Node = 0xFFFF,
 609 
 610     DEFINE_CLASS_ID(Multi, Node, 0)
 611       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 612         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 613           DEFINE_CLASS_ID(CallJava,         Call, 0)
 614             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 615             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 616           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 617             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 618           DEFINE_CLASS_ID(Allocate,         Call, 2)
 619             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 620           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 621             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 622             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 623           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 624       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 625         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 626           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 627           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 628         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 629           DEFINE_CLASS_ID(CountedLoopEnd, If, 0)
 630           DEFINE_CLASS_ID(RangeCheck, If, 1)
 631         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 632       DEFINE_CLASS_ID(Start,       Multi, 2)
 633       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 634         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 635         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 636 
 637     DEFINE_CLASS_ID(Mach,  Node, 1)
 638       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 639         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 640           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 641             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 642               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 643               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 644             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 645               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 646       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 647         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 648         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 649         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 650       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 651       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 652       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 653       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 654       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 655 
 656     DEFINE_CLASS_ID(Type,  Node, 2)
 657       DEFINE_CLASS_ID(Phi,   Type, 0)
 658       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 659         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 660         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 661       DEFINE_CLASS_ID(CMove, Type, 3)
 662       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 663       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 664         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 665         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 666       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 667         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 668         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 669 
 670     DEFINE_CLASS_ID(Proj,  Node, 3)
 671       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 672       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 673       DEFINE_CLASS_ID(IfTrue,    Proj, 2)
 674       DEFINE_CLASS_ID(IfFalse,   Proj, 3)
 675       DEFINE_CLASS_ID(Parm,      Proj, 4)
 676       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 677 
 678     DEFINE_CLASS_ID(Mem,   Node, 4)
 679       DEFINE_CLASS_ID(Load,  Mem, 0)
 680         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 681       DEFINE_CLASS_ID(Store, Mem, 1)
 682         DEFINE_CLASS_ID(StoreVector, Store, 0)
 683       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 684         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 685           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 686         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 687 
 688     DEFINE_CLASS_ID(Region, Node, 5)
 689       DEFINE_CLASS_ID(Loop, Region, 0)
 690         DEFINE_CLASS_ID(Root,        Loop, 0)
 691         DEFINE_CLASS_ID(CountedLoop, Loop, 1)
 692 
 693     DEFINE_CLASS_ID(Sub,   Node, 6)
 694       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 695         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 696         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 697 
 698     DEFINE_CLASS_ID(MergeMem, Node, 7)
 699     DEFINE_CLASS_ID(Bool,     Node, 8)
 700     DEFINE_CLASS_ID(AddP,     Node, 9)
 701     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 702     DEFINE_CLASS_ID(Add,      Node, 11)
 703     DEFINE_CLASS_ID(Mul,      Node, 12)
 704     DEFINE_CLASS_ID(Vector,   Node, 13)
 705     DEFINE_CLASS_ID(ClearArray, Node, 14)
 706 
 707     _max_classes  = ClassMask_ClearArray
 708   };
 709   #undef DEFINE_CLASS_ID
 710 
 711   // Flags are sorted by usage frequency.
 712   enum NodeFlags {
 713     Flag_is_Copy                     = 0x01, // should be first bit to avoid shift
 714     Flag_rematerialize               = Flag_is_Copy << 1,
 715     Flag_needs_anti_dependence_check = Flag_rematerialize << 1,
 716     Flag_is_macro                    = Flag_needs_anti_dependence_check << 1,
 717     Flag_is_Con                      = Flag_is_macro << 1,
 718     Flag_is_cisc_alternate           = Flag_is_Con << 1,
 719     Flag_is_dead_loop_safe           = Flag_is_cisc_alternate << 1,
 720     Flag_may_be_short_branch         = Flag_is_dead_loop_safe << 1,
 721     Flag_avoid_back_to_back_before   = Flag_may_be_short_branch << 1,
 722     Flag_avoid_back_to_back_after    = Flag_avoid_back_to_back_before << 1,
 723     Flag_has_call                    = Flag_avoid_back_to_back_after << 1,
 724     Flag_is_reduction                = Flag_has_call << 1,
 725     Flag_is_scheduled                = Flag_is_reduction << 1,
 726     Flag_has_vector_mask_set         = Flag_is_scheduled << 1,
 727     Flag_is_expensive                = Flag_has_vector_mask_set << 1,
 728     _max_flags = (Flag_is_expensive << 1) - 1 // allow flags combination
 729   };
 730 
 731 private:
 732   jushort _class_id;
 733   jushort _flags;
 734 
 735 protected:
 736   // These methods should be called from constructors only.
 737   void init_class_id(jushort c) {
 738     assert(c <= _max_classes, "invalid node class");
 739     _class_id = c; // cast out const
 740   }
 741   void init_flags(jushort fl) {
 742     assert(fl <= _max_flags, "invalid node flag");
 743     _flags |= fl;
 744   }
 745   void clear_flag(jushort fl) {
 746     assert(fl <= _max_flags, "invalid node flag");
 747     _flags &= ~fl;
 748   }
 749 
 750 public:
 751   const jushort class_id() const { return _class_id; }
 752 
 753   const jushort flags() const { return _flags; }
 754 
 755   void add_flag(jushort fl) { init_flags(fl); }
 756 
 757   void remove_flag(jushort fl) { clear_flag(fl); }
 758 
 759   // Return a dense integer opcode number
 760   virtual uint Opcode() const;
 761 
 762   // Virtual inherited Node size
 763   virtual uint size_of() const;
 764 
 765   // Other interesting Node properties
 766   #define DEFINE_CLASS_QUERY(type)                           \
 767   bool is_##type() const {                                   \
 768     return ((_class_id & ClassMask_##type) == Class_##type); \
 769   }                                                          \
 770   type##Node *as_##type() const {                            \
 771     assert(is_##type(), "invalid node class");               \
 772     return (type##Node*)this;                                \
 773   }                                                          \
 774   type##Node* isa_##type() const {                           \
 775     return (is_##type()) ? as_##type() : NULL;               \
 776   }
 777 
 778   DEFINE_CLASS_QUERY(AbstractLock)
 779   DEFINE_CLASS_QUERY(Add)
 780   DEFINE_CLASS_QUERY(AddP)
 781   DEFINE_CLASS_QUERY(Allocate)
 782   DEFINE_CLASS_QUERY(AllocateArray)
 783   DEFINE_CLASS_QUERY(ArrayCopy)
 784   DEFINE_CLASS_QUERY(Bool)
 785   DEFINE_CLASS_QUERY(BoxLock)
 786   DEFINE_CLASS_QUERY(Call)
 787   DEFINE_CLASS_QUERY(CallDynamicJava)
 788   DEFINE_CLASS_QUERY(CallJava)
 789   DEFINE_CLASS_QUERY(CallLeaf)
 790   DEFINE_CLASS_QUERY(CallRuntime)
 791   DEFINE_CLASS_QUERY(CallStaticJava)
 792   DEFINE_CLASS_QUERY(Catch)
 793   DEFINE_CLASS_QUERY(CatchProj)
 794   DEFINE_CLASS_QUERY(CheckCastPP)
 795   DEFINE_CLASS_QUERY(CastII)
 796   DEFINE_CLASS_QUERY(ConstraintCast)
 797   DEFINE_CLASS_QUERY(ClearArray)
 798   DEFINE_CLASS_QUERY(CMove)
 799   DEFINE_CLASS_QUERY(Cmp)
 800   DEFINE_CLASS_QUERY(CountedLoop)
 801   DEFINE_CLASS_QUERY(CountedLoopEnd)
 802   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 803   DEFINE_CLASS_QUERY(DecodeN)
 804   DEFINE_CLASS_QUERY(DecodeNKlass)
 805   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 806   DEFINE_CLASS_QUERY(EncodeP)
 807   DEFINE_CLASS_QUERY(EncodePKlass)
 808   DEFINE_CLASS_QUERY(FastLock)
 809   DEFINE_CLASS_QUERY(FastUnlock)
 810   DEFINE_CLASS_QUERY(If)
 811   DEFINE_CLASS_QUERY(RangeCheck)
 812   DEFINE_CLASS_QUERY(IfFalse)
 813   DEFINE_CLASS_QUERY(IfTrue)
 814   DEFINE_CLASS_QUERY(Initialize)
 815   DEFINE_CLASS_QUERY(Jump)
 816   DEFINE_CLASS_QUERY(JumpProj)
 817   DEFINE_CLASS_QUERY(Load)
 818   DEFINE_CLASS_QUERY(LoadStore)
 819   DEFINE_CLASS_QUERY(Lock)
 820   DEFINE_CLASS_QUERY(Loop)
 821   DEFINE_CLASS_QUERY(Mach)
 822   DEFINE_CLASS_QUERY(MachBranch)
 823   DEFINE_CLASS_QUERY(MachCall)
 824   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 825   DEFINE_CLASS_QUERY(MachCallJava)
 826   DEFINE_CLASS_QUERY(MachCallLeaf)
 827   DEFINE_CLASS_QUERY(MachCallRuntime)
 828   DEFINE_CLASS_QUERY(MachCallStaticJava)
 829   DEFINE_CLASS_QUERY(MachConstantBase)
 830   DEFINE_CLASS_QUERY(MachConstant)
 831   DEFINE_CLASS_QUERY(MachGoto)
 832   DEFINE_CLASS_QUERY(MachIf)
 833   DEFINE_CLASS_QUERY(MachNullCheck)
 834   DEFINE_CLASS_QUERY(MachProj)
 835   DEFINE_CLASS_QUERY(MachReturn)
 836   DEFINE_CLASS_QUERY(MachSafePoint)
 837   DEFINE_CLASS_QUERY(MachSpillCopy)
 838   DEFINE_CLASS_QUERY(MachTemp)
 839   DEFINE_CLASS_QUERY(MachMerge)
 840   DEFINE_CLASS_QUERY(Mem)
 841   DEFINE_CLASS_QUERY(MemBar)
 842   DEFINE_CLASS_QUERY(MemBarStoreStore)
 843   DEFINE_CLASS_QUERY(MergeMem)
 844   DEFINE_CLASS_QUERY(Mul)
 845   DEFINE_CLASS_QUERY(Multi)
 846   DEFINE_CLASS_QUERY(MultiBranch)
 847   DEFINE_CLASS_QUERY(Parm)
 848   DEFINE_CLASS_QUERY(PCTable)
 849   DEFINE_CLASS_QUERY(Phi)
 850   DEFINE_CLASS_QUERY(Proj)
 851   DEFINE_CLASS_QUERY(Region)
 852   DEFINE_CLASS_QUERY(Root)
 853   DEFINE_CLASS_QUERY(SafePoint)
 854   DEFINE_CLASS_QUERY(SafePointScalarObject)
 855   DEFINE_CLASS_QUERY(Start)
 856   DEFINE_CLASS_QUERY(Store)
 857   DEFINE_CLASS_QUERY(Sub)
 858   DEFINE_CLASS_QUERY(Type)
 859   DEFINE_CLASS_QUERY(Vector)
 860   DEFINE_CLASS_QUERY(LoadVector)
 861   DEFINE_CLASS_QUERY(StoreVector)
 862   DEFINE_CLASS_QUERY(Unlock)
 863 
 864   #undef DEFINE_CLASS_QUERY
 865 
 866   // duplicate of is_MachSpillCopy()
 867   bool is_SpillCopy () const {
 868     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 869   }
 870 
 871   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 872   // The data node which is safe to leave in dead loop during IGVN optimization.
 873   bool is_dead_loop_safe() const {
 874     return is_Phi() || (is_Proj() && in(0) == NULL) ||
 875            ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0 &&
 876             (!is_Proj() || !in(0)->is_Allocate()));
 877   }
 878 
 879   // is_Copy() returns copied edge index (0 or 1)
 880   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 881 
 882   virtual bool is_CFG() const { return false; }
 883 
 884   // If this node is control-dependent on a test, can it be
 885   // rerouted to a dominating equivalent test?  This is usually
 886   // true of non-CFG nodes, but can be false for operations which
 887   // depend for their correct sequencing on more than one test.
 888   // (In that case, hoisting to a dominating test may silently
 889   // skip some other important test.)
 890   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 891 
 892   // When building basic blocks, I need to have a notion of block beginning
 893   // Nodes, next block selector Nodes (block enders), and next block
 894   // projections.  These calls need to work on their machine equivalents.  The
 895   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 896   bool is_block_start() const {
 897     if ( is_Region() )
 898       return this == (const Node*)in(0);
 899     else
 900       return is_Start();
 901   }
 902 
 903   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 904   // Goto and Return.  This call also returns the block ending Node.
 905   virtual const Node *is_block_proj() const;
 906 
 907   // The node is a "macro" node which needs to be expanded before matching
 908   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 909   // The node is expensive: the best control is set during loop opts
 910   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 911 
 912   // An arithmetic node which accumulates a data in a loop.
 913   // It must have the loop's phi as input and provide a def to the phi.
 914   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 915 
 916   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
 917   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
 918 
 919   // Used in lcm to mark nodes that have scheduled
 920   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
 921 
 922 //----------------- Optimization
 923 
 924   // Get the worst-case Type output for this Node.
 925   virtual const class Type *bottom_type() const;
 926 
 927   // If we find a better type for a node, try to record it permanently.
 928   // Return true if this node actually changed.
 929   // Be sure to do the hash_delete game in the "rehash" variant.
 930   void raise_bottom_type(const Type* new_type);
 931 
 932   // Get the address type with which this node uses and/or defs memory,
 933   // or NULL if none.  The address type is conservatively wide.
 934   // Returns non-null for calls, membars, loads, stores, etc.
 935   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
 936   virtual const class TypePtr *adr_type() const { return NULL; }
 937 
 938   // Return an existing node which computes the same function as this node.
 939   // The optimistic combined algorithm requires this to return a Node which
 940   // is a small number of steps away (e.g., one of my inputs).
 941   virtual Node* Identity(PhaseGVN* phase);
 942 
 943   // Return the set of values this Node can take on at runtime.
 944   virtual const Type* Value(PhaseGVN* phase) const;
 945 
 946   // Return a node which is more "ideal" than the current node.
 947   // The invariants on this call are subtle.  If in doubt, read the
 948   // treatise in node.cpp above the default implemention AND TEST WITH
 949   // +VerifyIterativeGVN!
 950   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 951 
 952   // Some nodes have specific Ideal subgraph transformations only if they are
 953   // unique users of specific nodes. Such nodes should be put on IGVN worklist
 954   // for the transformations to happen.
 955   bool has_special_unique_user() const;
 956 
 957   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
 958   Node* find_exact_control(Node* ctrl);
 959 
 960   // Check if 'this' node dominates or equal to 'sub'.
 961   bool dominates(Node* sub, Node_List &nlist);
 962 
 963 protected:
 964   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
 965 public:
 966 
 967   // See if there is valid pipeline info
 968   static  const Pipeline *pipeline_class();
 969   virtual const Pipeline *pipeline() const;
 970 
 971   // Compute the latency from the def to this instruction of the ith input node
 972   uint latency(uint i);
 973 
 974   // Hash & compare functions, for pessimistic value numbering
 975 
 976   // If the hash function returns the special sentinel value NO_HASH,
 977   // the node is guaranteed never to compare equal to any other node.
 978   // If we accidentally generate a hash with value NO_HASH the node
 979   // won't go into the table and we'll lose a little optimization.
 980   enum { NO_HASH = 0 };
 981   virtual uint hash() const;
 982   virtual uint cmp( const Node &n ) const;
 983 
 984   // Operation appears to be iteratively computed (such as an induction variable)
 985   // It is possible for this operation to return false for a loop-varying
 986   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
 987   bool is_iteratively_computed();
 988 
 989   // Determine if a node is Counted loop induction variable.
 990   // The method is defined in loopnode.cpp.
 991   const Node* is_loop_iv() const;
 992 
 993   // Return a node with opcode "opc" and same inputs as "this" if one can
 994   // be found; Otherwise return NULL;
 995   Node* find_similar(uint opc);
 996 
 997   // Return the unique control out if only one. Null if none or more than one.
 998   Node* unique_ctrl_out() const;
 999 
1000   // Set control or add control as precedence edge
1001   void ensure_control_or_add_prec(Node* c);
1002 
1003 //----------------- Code Generation
1004 
1005   // Ideal register class for Matching.  Zero means unmatched instruction
1006   // (these are cloned instead of converted to machine nodes).
1007   virtual uint ideal_reg() const;
1008 
1009   static const uint NotAMachineReg;   // must be > max. machine register
1010 
1011   // Do we Match on this edge index or not?  Generally false for Control
1012   // and true for everything else.  Weird for calls & returns.
1013   virtual uint match_edge(uint idx) const;
1014 
1015   // Register class output is returned in
1016   virtual const RegMask &out_RegMask() const;
1017   // Register class input is expected in
1018   virtual const RegMask &in_RegMask(uint) const;
1019   // Should we clone rather than spill this instruction?
1020   bool rematerialize() const;
1021 
1022   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1023   virtual JVMState* jvms() const;
1024 
1025   // Print as assembly
1026   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1027   // Emit bytes starting at parameter 'ptr'
1028   // Bump 'ptr' by the number of output bytes
1029   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1030   // Size of instruction in bytes
1031   virtual uint size(PhaseRegAlloc *ra_) const;
1032 
1033   // Convenience function to extract an integer constant from a node.
1034   // If it is not an integer constant (either Con, CastII, or Mach),
1035   // return value_if_unknown.
1036   jint find_int_con(jint value_if_unknown) const {
1037     const TypeInt* t = find_int_type();
1038     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1039   }
1040   // Return the constant, knowing it is an integer constant already
1041   jint get_int() const {
1042     const TypeInt* t = find_int_type();
1043     guarantee(t != NULL, "must be con");
1044     return t->get_con();
1045   }
1046   // Here's where the work is done.  Can produce non-constant int types too.
1047   const TypeInt* find_int_type() const;
1048 
1049   // Same thing for long (and intptr_t, via type.hpp):
1050   jlong get_long() const {
1051     const TypeLong* t = find_long_type();
1052     guarantee(t != NULL, "must be con");
1053     return t->get_con();
1054   }
1055   jlong find_long_con(jint value_if_unknown) const {
1056     const TypeLong* t = find_long_type();
1057     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1058   }
1059   const TypeLong* find_long_type() const;
1060 
1061   const TypePtr* get_ptr_type() const;
1062 
1063   // These guys are called by code generated by ADLC:
1064   intptr_t get_ptr() const;
1065   intptr_t get_narrowcon() const;
1066   jdouble getd() const;
1067   jfloat getf() const;
1068 
1069   // Nodes which are pinned into basic blocks
1070   virtual bool pinned() const { return false; }
1071 
1072   // Nodes which use memory without consuming it, hence need antidependences
1073   // More specifically, needs_anti_dependence_check returns true iff the node
1074   // (a) does a load, and (b) does not perform a store (except perhaps to a
1075   // stack slot or some other unaliased location).
1076   bool needs_anti_dependence_check() const;
1077 
1078   // Return which operand this instruction may cisc-spill. In other words,
1079   // return operand position that can convert from reg to memory access
1080   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1081   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1082 
1083 //----------------- Graph walking
1084 public:
1085   // Walk and apply member functions recursively.
1086   // Supplied (this) pointer is root.
1087   void walk(NFunc pre, NFunc post, void *env);
1088   static void nop(Node &, void*); // Dummy empty function
1089   static void packregion( Node &n, void* );
1090 private:
1091   void walk_(NFunc pre, NFunc post, void *env, VectorSet &visited);
1092 
1093 //----------------- Printing, etc
1094 public:
1095 #ifndef PRODUCT
1096   Node* find(int idx) const;         // Search the graph for the given idx.
1097   Node* find_ctrl(int idx) const;    // Search control ancestors for the given idx.
1098   void dump() const { dump("\n"); }  // Print this node.
1099   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1100   void dump(int depth) const;        // Print this node, recursively to depth d
1101   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1102   void dump_comp() const;            // Print this node in compact representation.
1103   // Print this node in compact representation.
1104   void dump_comp(const char* suffix, outputStream *st = tty) const;
1105   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1106   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1107   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1108   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1109   // Print compact per-node info
1110   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1111   void dump_related() const;             // Print related nodes (depends on node at hand).
1112   // Print related nodes up to given depths for input and output nodes.
1113   void dump_related(uint d_in, uint d_out) const;
1114   void dump_related_compact() const;     // Print related nodes in compact representation.
1115   // Collect related nodes.
1116   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1117   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1118   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1119 
1120   // Node collectors, to be used in implementations of Node::rel().
1121   // Collect the entire data input graph. Include control inputs if requested.
1122   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1123   // Collect the entire control input graph. Include data inputs if requested.
1124   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1125   // Collect the entire output graph until hitting and including control nodes.
1126   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1127 
1128   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1129   void verify() const;               // Check Def-Use info for my subgraph
1130   static void verify_recur(const Node *n, int verify_depth, VectorSet &old_space, VectorSet &new_space);
1131 
1132   // This call defines a class-unique string used to identify class instances
1133   virtual const char *Name() const;
1134 
1135   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1136   // RegMask Print Functions
1137   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1138   void dump_out_regmask() { out_RegMask().dump(); }
1139   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1140   void fast_dump() const {
1141     tty->print("%4d: %-17s", _idx, Name());
1142     for (uint i = 0; i < len(); i++)
1143       if (in(i))
1144         tty->print(" %4d", in(i)->_idx);
1145       else
1146         tty->print(" NULL");
1147     tty->print("\n");
1148   }
1149 #endif
1150 #ifdef ASSERT
1151   void verify_construction();
1152   bool verify_jvms(const JVMState* jvms) const;
1153   int  _debug_idx;                     // Unique value assigned to every node.
1154   int   debug_idx() const              { return _debug_idx; }
1155   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1156 
1157   Node* _debug_orig;                   // Original version of this, if any.
1158   Node*  debug_orig() const            { return _debug_orig; }
1159   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1160 
1161   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1162   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1163   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1164 
1165   static void init_NodeProperty();
1166 
1167   #if OPTO_DU_ITERATOR_ASSERT
1168   const Node* _last_del;               // The last deleted node.
1169   uint        _del_tick;               // Bumped when a deletion happens..
1170   #endif
1171 #endif
1172 };
1173 
1174 
1175 #ifndef PRODUCT
1176 
1177 // Used in debugging code to avoid walking across dead or uninitialized edges.
1178 inline bool NotANode(const Node* n) {
1179   if (n == NULL)                   return true;
1180   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1181   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1182   return false;
1183 }
1184 
1185 #endif
1186 
1187 
1188 //-----------------------------------------------------------------------------
1189 // Iterators over DU info, and associated Node functions.
1190 
1191 #if OPTO_DU_ITERATOR_ASSERT
1192 
1193 // Common code for assertion checking on DU iterators.
1194 class DUIterator_Common VALUE_OBJ_CLASS_SPEC {
1195 #ifdef ASSERT
1196  protected:
1197   bool         _vdui;               // cached value of VerifyDUIterators
1198   const Node*  _node;               // the node containing the _out array
1199   uint         _outcnt;             // cached node->_outcnt
1200   uint         _del_tick;           // cached node->_del_tick
1201   Node*        _last;               // last value produced by the iterator
1202 
1203   void sample(const Node* node);    // used by c'tor to set up for verifies
1204   void verify(const Node* node, bool at_end_ok = false);
1205   void verify_resync();
1206   void reset(const DUIterator_Common& that);
1207 
1208 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1209   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1210 #else
1211   #define I_VDUI_ONLY(i,x) { }
1212 #endif //ASSERT
1213 };
1214 
1215 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1216 
1217 // Default DU iterator.  Allows appends onto the out array.
1218 // Allows deletion from the out array only at the current point.
1219 // Usage:
1220 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1221 //    Node* y = x->out(i);
1222 //    ...
1223 //  }
1224 // Compiles in product mode to a unsigned integer index, which indexes
1225 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1226 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1227 // before continuing the loop.  You must delete only the last-produced
1228 // edge.  You must delete only a single copy of the last-produced edge,
1229 // or else you must delete all copies at once (the first time the edge
1230 // is produced by the iterator).
1231 class DUIterator : public DUIterator_Common {
1232   friend class Node;
1233 
1234   // This is the index which provides the product-mode behavior.
1235   // Whatever the product-mode version of the system does to the
1236   // DUI index is done to this index.  All other fields in
1237   // this class are used only for assertion checking.
1238   uint         _idx;
1239 
1240   #ifdef ASSERT
1241   uint         _refresh_tick;    // Records the refresh activity.
1242 
1243   void sample(const Node* node); // Initialize _refresh_tick etc.
1244   void verify(const Node* node, bool at_end_ok = false);
1245   void verify_increment();       // Verify an increment operation.
1246   void verify_resync();          // Verify that we can back up over a deletion.
1247   void verify_finish();          // Verify that the loop terminated properly.
1248   void refresh();                // Resample verification info.
1249   void reset(const DUIterator& that);  // Resample after assignment.
1250   #endif
1251 
1252   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1253     { _idx = 0;                         debug_only(sample(node)); }
1254 
1255  public:
1256   // initialize to garbage; clear _vdui to disable asserts
1257   DUIterator()
1258     { /*initialize to garbage*/         debug_only(_vdui = false); }
1259 
1260   void operator++(int dummy_to_specify_postfix_op)
1261     { _idx++;                           VDUI_ONLY(verify_increment()); }
1262 
1263   void operator--()
1264     { VDUI_ONLY(verify_resync());       --_idx; }
1265 
1266   ~DUIterator()
1267     { VDUI_ONLY(verify_finish()); }
1268 
1269   void operator=(const DUIterator& that)
1270     { _idx = that._idx;                 debug_only(reset(that)); }
1271 };
1272 
1273 DUIterator Node::outs() const
1274   { return DUIterator(this, 0); }
1275 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1276   { I_VDUI_ONLY(i, i.refresh());        return i; }
1277 bool Node::has_out(DUIterator& i) const
1278   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1279 Node*    Node::out(DUIterator& i) const
1280   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1281 
1282 
1283 // Faster DU iterator.  Disallows insertions into the out array.
1284 // Allows deletion from the out array only at the current point.
1285 // Usage:
1286 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1287 //    Node* y = x->fast_out(i);
1288 //    ...
1289 //  }
1290 // Compiles in product mode to raw Node** pointer arithmetic, with
1291 // no reloading of pointers from the original node x.  If you delete,
1292 // you must perform "--i; --imax" just before continuing the loop.
1293 // If you delete multiple copies of the same edge, you must decrement
1294 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1295 class DUIterator_Fast : public DUIterator_Common {
1296   friend class Node;
1297   friend class DUIterator_Last;
1298 
1299   // This is the pointer which provides the product-mode behavior.
1300   // Whatever the product-mode version of the system does to the
1301   // DUI pointer is done to this pointer.  All other fields in
1302   // this class are used only for assertion checking.
1303   Node**       _outp;
1304 
1305   #ifdef ASSERT
1306   void verify(const Node* node, bool at_end_ok = false);
1307   void verify_limit();
1308   void verify_resync();
1309   void verify_relimit(uint n);
1310   void reset(const DUIterator_Fast& that);
1311   #endif
1312 
1313   // Note:  offset must be signed, since -1 is sometimes passed
1314   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1315     { _outp = node->_out + offset;      debug_only(sample(node)); }
1316 
1317  public:
1318   // initialize to garbage; clear _vdui to disable asserts
1319   DUIterator_Fast()
1320     { /*initialize to garbage*/         debug_only(_vdui = false); }
1321 
1322   void operator++(int dummy_to_specify_postfix_op)
1323     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1324 
1325   void operator--()
1326     { VDUI_ONLY(verify_resync());       --_outp; }
1327 
1328   void operator-=(uint n)   // applied to the limit only
1329     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1330 
1331   bool operator<(DUIterator_Fast& limit) {
1332     I_VDUI_ONLY(*this, this->verify(_node, true));
1333     I_VDUI_ONLY(limit, limit.verify_limit());
1334     return _outp < limit._outp;
1335   }
1336 
1337   void operator=(const DUIterator_Fast& that)
1338     { _outp = that._outp;               debug_only(reset(that)); }
1339 };
1340 
1341 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1342   // Assign a limit pointer to the reference argument:
1343   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1344   // Return the base pointer:
1345   return DUIterator_Fast(this, 0);
1346 }
1347 Node* Node::fast_out(DUIterator_Fast& i) const {
1348   I_VDUI_ONLY(i, i.verify(this));
1349   return debug_only(i._last=) *i._outp;
1350 }
1351 
1352 
1353 // Faster DU iterator.  Requires each successive edge to be removed.
1354 // Does not allow insertion of any edges.
1355 // Usage:
1356 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1357 //    Node* y = x->last_out(i);
1358 //    ...
1359 //  }
1360 // Compiles in product mode to raw Node** pointer arithmetic, with
1361 // no reloading of pointers from the original node x.
1362 class DUIterator_Last : private DUIterator_Fast {
1363   friend class Node;
1364 
1365   #ifdef ASSERT
1366   void verify(const Node* node, bool at_end_ok = false);
1367   void verify_limit();
1368   void verify_step(uint num_edges);
1369   #endif
1370 
1371   // Note:  offset must be signed, since -1 is sometimes passed
1372   DUIterator_Last(const Node* node, ptrdiff_t offset)
1373     : DUIterator_Fast(node, offset) { }
1374 
1375   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1376   void operator<(int)                              {} // do not use
1377 
1378  public:
1379   DUIterator_Last() { }
1380   // initialize to garbage
1381 
1382   void operator--()
1383     { _outp--;              VDUI_ONLY(verify_step(1));  }
1384 
1385   void operator-=(uint n)
1386     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1387 
1388   bool operator>=(DUIterator_Last& limit) {
1389     I_VDUI_ONLY(*this, this->verify(_node, true));
1390     I_VDUI_ONLY(limit, limit.verify_limit());
1391     return _outp >= limit._outp;
1392   }
1393 
1394   void operator=(const DUIterator_Last& that)
1395     { DUIterator_Fast::operator=(that); }
1396 };
1397 
1398 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1399   // Assign a limit pointer to the reference argument:
1400   imin = DUIterator_Last(this, 0);
1401   // Return the initial pointer:
1402   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1403 }
1404 Node* Node::last_out(DUIterator_Last& i) const {
1405   I_VDUI_ONLY(i, i.verify(this));
1406   return debug_only(i._last=) *i._outp;
1407 }
1408 
1409 #endif //OPTO_DU_ITERATOR_ASSERT
1410 
1411 #undef I_VDUI_ONLY
1412 #undef VDUI_ONLY
1413 
1414 // An Iterator that truly follows the iterator pattern.  Doesn't
1415 // support deletion but could be made to.
1416 //
1417 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1418 //     Node* m = i.get();
1419 //
1420 class SimpleDUIterator : public StackObj {
1421  private:
1422   Node* node;
1423   DUIterator_Fast i;
1424   DUIterator_Fast imax;
1425  public:
1426   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1427   bool has_next() { return i < imax; }
1428   void next() { i++; }
1429   Node* get() { return node->fast_out(i); }
1430 };
1431 
1432 
1433 //-----------------------------------------------------------------------------
1434 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1435 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1436 // Note that the constructor just zeros things, and since I use Arena
1437 // allocation I do not need a destructor to reclaim storage.
1438 class Node_Array : public ResourceObj {
1439   friend class VMStructs;
1440 protected:
1441   Arena *_a;                    // Arena to allocate in
1442   uint   _max;
1443   Node **_nodes;
1444   void   grow( uint i );        // Grow array node to fit
1445 public:
1446   Node_Array(Arena *a) : _a(a), _max(OptoNodeListSize) {
1447     _nodes = NEW_ARENA_ARRAY( a, Node *, OptoNodeListSize );
1448     for( int i = 0; i < OptoNodeListSize; i++ ) {
1449       _nodes[i] = NULL;
1450     }
1451   }
1452 
1453   Node_Array(Node_Array *na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1454   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1455   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1456   Node *at( uint i ) const { assert(i<_max,"oob"); return _nodes[i]; }
1457   Node **adr() { return _nodes; }
1458   // Extend the mapping: index i maps to Node *n.
1459   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1460   void insert( uint i, Node *n );
1461   void remove( uint i );        // Remove, preserving order
1462   void sort( C_sort_func_t func);
1463   void reset( Arena *new_a );   // Zap mapping to empty; reclaim storage
1464   void clear();                 // Set all entries to NULL, keep storage
1465   uint Size() const { return _max; }
1466   void dump() const;
1467 };
1468 
1469 class Node_List : public Node_Array {
1470   friend class VMStructs;
1471   uint _cnt;
1472 public:
1473   Node_List() : Node_Array(Thread::current()->resource_area()), _cnt(0) {}
1474   Node_List(Arena *a) : Node_Array(a), _cnt(0) {}
1475   bool contains(const Node* n) const {
1476     for (uint e = 0; e < size(); e++) {
1477       if (at(e) == n) return true;
1478     }
1479     return false;
1480   }
1481   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1482   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1483   void push( Node *b ) { map(_cnt++,b); }
1484   void yank( Node *n );         // Find and remove
1485   Node *pop() { return _nodes[--_cnt]; }
1486   Node *rpop() { Node *b = _nodes[0]; _nodes[0]=_nodes[--_cnt]; return b;}
1487   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1488   uint size() const { return _cnt; }
1489   void dump() const;
1490   void dump_simple() const;
1491 };
1492 
1493 //------------------------------Unique_Node_List-------------------------------
1494 class Unique_Node_List : public Node_List {
1495   friend class VMStructs;
1496   VectorSet _in_worklist;
1497   uint _clock_index;            // Index in list where to pop from next
1498 public:
1499   Unique_Node_List() : Node_List(), _in_worklist(Thread::current()->resource_area()), _clock_index(0) {}
1500   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1501 
1502   void remove( Node *n );
1503   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1504   VectorSet &member_set(){ return _in_worklist; }
1505 
1506   void push( Node *b ) {
1507     if( !_in_worklist.test_set(b->_idx) )
1508       Node_List::push(b);
1509   }
1510   Node *pop() {
1511     if( _clock_index >= size() ) _clock_index = 0;
1512     Node *b = at(_clock_index);
1513     map( _clock_index, Node_List::pop());
1514     if (size() != 0) _clock_index++; // Always start from 0
1515     _in_worklist >>= b->_idx;
1516     return b;
1517   }
1518   Node *remove( uint i ) {
1519     Node *b = Node_List::at(i);
1520     _in_worklist >>= b->_idx;
1521     map(i,Node_List::pop());
1522     return b;
1523   }
1524   void yank( Node *n ) { _in_worklist >>= n->_idx; Node_List::yank(n); }
1525   void  clear() {
1526     _in_worklist.Clear();        // Discards storage but grows automatically
1527     Node_List::clear();
1528     _clock_index = 0;
1529   }
1530 
1531   // Used after parsing to remove useless nodes before Iterative GVN
1532   void remove_useless_nodes(VectorSet &useful);
1533 
1534 #ifndef PRODUCT
1535   void print_set() const { _in_worklist.print(); }
1536 #endif
1537 };
1538 
1539 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1540 inline void Compile::record_for_igvn(Node* n) {
1541   _for_igvn->push(n);
1542 }
1543 
1544 //------------------------------Node_Stack-------------------------------------
1545 class Node_Stack {
1546   friend class VMStructs;
1547 protected:
1548   struct INode {
1549     Node *node; // Processed node
1550     uint  indx; // Index of next node's child
1551   };
1552   INode *_inode_top; // tos, stack grows up
1553   INode *_inode_max; // End of _inodes == _inodes + _max
1554   INode *_inodes;    // Array storage for the stack
1555   Arena *_a;         // Arena to allocate in
1556   void grow();
1557 public:
1558   Node_Stack(int size) {
1559     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1560     _a = Thread::current()->resource_area();
1561     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1562     _inode_max = _inodes + max;
1563     _inode_top = _inodes - 1; // stack is empty
1564   }
1565 
1566   Node_Stack(Arena *a, int size) : _a(a) {
1567     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1568     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1569     _inode_max = _inodes + max;
1570     _inode_top = _inodes - 1; // stack is empty
1571   }
1572 
1573   void pop() {
1574     assert(_inode_top >= _inodes, "node stack underflow");
1575     --_inode_top;
1576   }
1577   void push(Node *n, uint i) {
1578     ++_inode_top;
1579     if (_inode_top >= _inode_max) grow();
1580     INode *top = _inode_top; // optimization
1581     top->node = n;
1582     top->indx = i;
1583   }
1584   Node *node() const {
1585     return _inode_top->node;
1586   }
1587   Node* node_at(uint i) const {
1588     assert(_inodes + i <= _inode_top, "in range");
1589     return _inodes[i].node;
1590   }
1591   uint index() const {
1592     return _inode_top->indx;
1593   }
1594   uint index_at(uint i) const {
1595     assert(_inodes + i <= _inode_top, "in range");
1596     return _inodes[i].indx;
1597   }
1598   void set_node(Node *n) {
1599     _inode_top->node = n;
1600   }
1601   void set_index(uint i) {
1602     _inode_top->indx = i;
1603   }
1604   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1605   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1606   bool is_nonempty() const { return (_inode_top >= _inodes); }
1607   bool is_empty() const { return (_inode_top < _inodes); }
1608   void clear() { _inode_top = _inodes - 1; } // retain storage
1609 
1610   // Node_Stack is used to map nodes.
1611   Node* find(uint idx) const;
1612 };
1613 
1614 
1615 //-----------------------------Node_Notes--------------------------------------
1616 // Debugging or profiling annotations loosely and sparsely associated
1617 // with some nodes.  See Compile::node_notes_at for the accessor.
1618 class Node_Notes VALUE_OBJ_CLASS_SPEC {
1619   friend class VMStructs;
1620   JVMState* _jvms;
1621 
1622 public:
1623   Node_Notes(JVMState* jvms = NULL) {
1624     _jvms = jvms;
1625   }
1626 
1627   JVMState* jvms()            { return _jvms; }
1628   void  set_jvms(JVMState* x) {        _jvms = x; }
1629 
1630   // True if there is nothing here.
1631   bool is_clear() {
1632     return (_jvms == NULL);
1633   }
1634 
1635   // Make there be nothing here.
1636   void clear() {
1637     _jvms = NULL;
1638   }
1639 
1640   // Make a new, clean node notes.
1641   static Node_Notes* make(Compile* C) {
1642     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1643     nn->clear();
1644     return nn;
1645   }
1646 
1647   Node_Notes* clone(Compile* C) {
1648     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1649     (*nn) = (*this);
1650     return nn;
1651   }
1652 
1653   // Absorb any information from source.
1654   bool update_from(Node_Notes* source) {
1655     bool changed = false;
1656     if (source != NULL) {
1657       if (source->jvms() != NULL) {
1658         set_jvms(source->jvms());
1659         changed = true;
1660       }
1661     }
1662     return changed;
1663   }
1664 };
1665 
1666 // Inlined accessors for Compile::node_nodes that require the preceding class:
1667 inline Node_Notes*
1668 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1669                            int idx, bool can_grow) {
1670   assert(idx >= 0, "oob");
1671   int block_idx = (idx >> _log2_node_notes_block_size);
1672   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1673   if (grow_by >= 0) {
1674     if (!can_grow)  return NULL;
1675     grow_node_notes(arr, grow_by + 1);
1676   }
1677   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1678   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1679 }
1680 
1681 inline bool
1682 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1683   if (value == NULL || value->is_clear())
1684     return false;  // nothing to write => write nothing
1685   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1686   assert(loc != NULL, "");
1687   return loc->update_from(value);
1688 }
1689 
1690 
1691 //------------------------------TypeNode---------------------------------------
1692 // Node with a Type constant.
1693 class TypeNode : public Node {
1694 protected:
1695   virtual uint hash() const;    // Check the type
1696   virtual uint cmp( const Node &n ) const;
1697   virtual uint size_of() const; // Size is bigger
1698   const Type* const _type;
1699 public:
1700   void set_type(const Type* t) {
1701     assert(t != NULL, "sanity");
1702     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1703     *(const Type**)&_type = t;   // cast away const-ness
1704     // If this node is in the hash table, make sure it doesn't need a rehash.
1705     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1706   }
1707   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1708   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1709     init_class_id(Class_Type);
1710   }
1711   virtual const Type* Value(PhaseGVN* phase) const;
1712   virtual const Type *bottom_type() const;
1713   virtual       uint  ideal_reg() const;
1714 #ifndef PRODUCT
1715   virtual void dump_spec(outputStream *st) const;
1716   virtual void dump_compact_spec(outputStream *st) const;
1717 #endif
1718 };
1719 
1720 #endif // SHARE_VM_OPTO_NODE_HPP