1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_OPTO_NODE_HPP
  26 #define SHARE_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 
  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 GetFPNode;
  76 class IfNode;
  77 class IfProjNode;
  78 class IfFalseNode;
  79 class IfTrueNode;
  80 class InitializeNode;
  81 class JVMState;
  82 class JumpNode;
  83 class JumpProjNode;
  84 class LoadNode;
  85 class LoadBarrierNode;
  86 class LoadBarrierSlowRegNode;
  87 class LoadStoreNode;
  88 class LoadStoreConditionalNode;
  89 class LockNode;
  90 class LoopNode;
  91 class MachBranchNode;
  92 class MachCallDynamicJavaNode;
  93 class MachCallJavaNode;
  94 class MachCallLeafNode;
  95 class MachCallNode;
  96 class MachCallRuntimeNode;
  97 class MachCallStaticJavaNode;
  98 class MachConstantBaseNode;
  99 class MachConstantNode;
 100 class MachGotoNode;
 101 class MachIfNode;
 102 class MachJumpNode;
 103 class MachNode;
 104 class MachNullCheckNode;
 105 class MachProjNode;
 106 class MachReturnNode;
 107 class MachSafePointNode;
 108 class MachSpillCopyNode;
 109 class MachTempNode;
 110 class MachMergeNode;
 111 class MachMemBarNode;
 112 class Matcher;
 113 class MemBarNode;
 114 class MemBarStoreStoreNode;
 115 class MemNode;
 116 class MergeMemNode;
 117 class MulNode;
 118 class MultiNode;
 119 class MultiBranchNode;
 120 class NeverBranchNode;
 121 class OuterStripMinedLoopNode;
 122 class OuterStripMinedLoopEndNode;
 123 class Node;
 124 class Node_Array;
 125 class Node_List;
 126 class Node_Stack;
 127 class NullCheckNode;
 128 class OopMap;
 129 class ParmNode;
 130 class PCTableNode;
 131 class PhaseCCP;
 132 class PhaseGVN;
 133 class PhaseIterGVN;
 134 class PhaseRegAlloc;
 135 class PhaseTransform;
 136 class PhaseValues;
 137 class PhiNode;
 138 class Pipeline;
 139 class ProjNode;
 140 class RangeCheckNode;
 141 class RegMask;
 142 class RegionNode;
 143 class RootNode;
 144 class SafePointNode;
 145 class SafePointScalarObjectNode;
 146 class StartNode;
 147 class State;
 148 class StoreNode;
 149 class SubNode;
 150 class Type;
 151 class TypeNode;
 152 class UnlockNode;
 153 class VectorNode;
 154 class LoadVectorNode;
 155 class StoreVectorNode;
 156 class VectorSet;
 157 typedef void (*NFunc)(Node&,void*);
 158 extern "C" {
 159   typedef int (*C_sort_func_t)(const void *, const void *);
 160 }
 161 
 162 // The type of all node counts and indexes.
 163 // It must hold at least 16 bits, but must also be fast to load and store.
 164 // This type, if less than 32 bits, could limit the number of possible nodes.
 165 // (To make this type platform-specific, move to globalDefinitions_xxx.hpp.)
 166 typedef unsigned int node_idx_t;
 167 
 168 
 169 #ifndef OPTO_DU_ITERATOR_ASSERT
 170 #ifdef ASSERT
 171 #define OPTO_DU_ITERATOR_ASSERT 1
 172 #else
 173 #define OPTO_DU_ITERATOR_ASSERT 0
 174 #endif
 175 #endif //OPTO_DU_ITERATOR_ASSERT
 176 
 177 #if OPTO_DU_ITERATOR_ASSERT
 178 class DUIterator;
 179 class DUIterator_Fast;
 180 class DUIterator_Last;
 181 #else
 182 typedef uint   DUIterator;
 183 typedef Node** DUIterator_Fast;
 184 typedef Node** DUIterator_Last;
 185 #endif
 186 
 187 // Node Sentinel
 188 #define NodeSentinel (Node*)-1
 189 
 190 // Unknown count frequency
 191 #define COUNT_UNKNOWN (-1.0f)
 192 
 193 //------------------------------Node-------------------------------------------
 194 // Nodes define actions in the program.  They create values, which have types.
 195 // They are both vertices in a directed graph and program primitives.  Nodes
 196 // are labeled; the label is the "opcode", the primitive function in the lambda
 197 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 198 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 199 // the Node's function.  These inputs also define a Type equation for the Node.
 200 // Solving these Type equations amounts to doing dataflow analysis.
 201 // Control and data are uniformly represented in the graph.  Finally, Nodes
 202 // have a unique dense integer index which is used to index into side arrays
 203 // whenever I have phase-specific information.
 204 
 205 class Node {
 206   friend class VMStructs;
 207 
 208   // Lots of restrictions on cloning Nodes
 209   Node(const Node&);            // not defined; linker error to use these
 210   Node &operator=(const Node &rhs);
 211 
 212 public:
 213   friend class Compile;
 214   #if OPTO_DU_ITERATOR_ASSERT
 215   friend class DUIterator_Common;
 216   friend class DUIterator;
 217   friend class DUIterator_Fast;
 218   friend class DUIterator_Last;
 219   #endif
 220 
 221   // Because Nodes come and go, I define an Arena of Node structures to pull
 222   // from.  This should allow fast access to node creation & deletion.  This
 223   // field is a local cache of a value defined in some "program fragment" for
 224   // which these Nodes are just a part of.
 225 
 226   inline void* operator new(size_t x) throw() {
 227     Compile* C = Compile::current();
 228     Node* n = (Node*)C->node_arena()->Amalloc_D(x);
 229     return (void*)n;
 230   }
 231 
 232   // Delete is a NOP
 233   void operator delete( void *ptr ) {}
 234   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 235   void destruct();
 236 
 237   // Create a new Node.  Required is the number is of inputs required for
 238   // semantic correctness.
 239   Node( uint required );
 240 
 241   // Create a new Node with given input edges.
 242   // This version requires use of the "edge-count" new.
 243   // E.g.  new (C,3) FooNode( C, NULL, left, right );
 244   Node( Node *n0 );
 245   Node( Node *n0, Node *n1 );
 246   Node( Node *n0, Node *n1, Node *n2 );
 247   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 248   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 249   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 250   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 251             Node *n4, Node *n5, Node *n6 );
 252 
 253   // Clone an inherited Node given only the base Node type.
 254   Node* clone() const;
 255 
 256   // Clone a Node, immediately supplying one or two new edges.
 257   // The first and second arguments, if non-null, replace in(1) and in(2),
 258   // respectively.
 259   Node* clone_with_data_edge(Node* in1, Node* in2 = NULL) const {
 260     Node* nn = clone();
 261     if (in1 != NULL)  nn->set_req(1, in1);
 262     if (in2 != NULL)  nn->set_req(2, in2);
 263     return nn;
 264   }
 265 
 266 private:
 267   // Shared setup for the above constructors.
 268   // Handles all interactions with Compile::current.
 269   // Puts initial values in all Node fields except _idx.
 270   // Returns the initial value for _idx, which cannot
 271   // be initialized by assignment.
 272   inline int Init(int req);
 273 
 274 //----------------- input edge handling
 275 protected:
 276   friend class PhaseCFG;        // Access to address of _in array elements
 277   Node **_in;                   // Array of use-def references to Nodes
 278   Node **_out;                  // Array of def-use references to Nodes
 279 
 280   // Input edges are split into two categories.  Required edges are required
 281   // for semantic correctness; order is important and NULLs are allowed.
 282   // Precedence edges are used to help determine execution order and are
 283   // added, e.g., for scheduling purposes.  They are unordered and not
 284   // duplicated; they have no embedded NULLs.  Edges from 0 to _cnt-1
 285   // are required, from _cnt to _max-1 are precedence edges.
 286   node_idx_t _cnt;              // Total number of required Node inputs.
 287 
 288   node_idx_t _max;              // Actual length of input array.
 289 
 290   // Output edges are an unordered list of def-use edges which exactly
 291   // correspond to required input edges which point from other nodes
 292   // to this one.  Thus the count of the output edges is the number of
 293   // users of this node.
 294   node_idx_t _outcnt;           // Total number of Node outputs.
 295 
 296   node_idx_t _outmax;           // Actual length of output array.
 297 
 298   // Grow the actual input array to the next larger power-of-2 bigger than len.
 299   void grow( uint len );
 300   // Grow the output array to the next larger power-of-2 bigger than len.
 301   void out_grow( uint len );
 302 
 303  public:
 304   // Each Node is assigned a unique small/dense number.  This number is used
 305   // to index into auxiliary arrays of data and bit vectors.
 306   // The field _idx is declared constant to defend against inadvertent assignments,
 307   // since it is used by clients as a naked field. However, the field's value can be
 308   // changed using the set_idx() method.
 309   //
 310   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 311   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 312   // preserved in _parse_idx.
 313   const node_idx_t _idx;
 314   DEBUG_ONLY(const node_idx_t _parse_idx;)
 315 
 316   // Get the (read-only) number of input edges
 317   uint req() const { return _cnt; }
 318   uint len() const { return _max; }
 319   // Get the (read-only) number of output edges
 320   uint outcnt() const { return _outcnt; }
 321 
 322 #if OPTO_DU_ITERATOR_ASSERT
 323   // Iterate over the out-edges of this node.  Deletions are illegal.
 324   inline DUIterator outs() const;
 325   // Use this when the out array might have changed to suppress asserts.
 326   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 327   // Does the node have an out at this position?  (Used for iteration.)
 328   inline bool has_out(DUIterator& i) const;
 329   inline Node*    out(DUIterator& i) const;
 330   // Iterate over the out-edges of this node.  All changes are illegal.
 331   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 332   inline Node*    fast_out(DUIterator_Fast& i) const;
 333   // Iterate over the out-edges of this node, deleting one at a time.
 334   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 335   inline Node*    last_out(DUIterator_Last& i) const;
 336   // The inline bodies of all these methods are after the iterator definitions.
 337 #else
 338   // Iterate over the out-edges of this node.  Deletions are illegal.
 339   // This iteration uses integral indexes, to decouple from array reallocations.
 340   DUIterator outs() const  { return 0; }
 341   // Use this when the out array might have changed to suppress asserts.
 342   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 343 
 344   // Reference to the i'th output Node.  Error if out of bounds.
 345   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 346   // Does the node have an out at this position?  (Used for iteration.)
 347   bool has_out(DUIterator i) const { return i < _outcnt; }
 348 
 349   // Iterate over the out-edges of this node.  All changes are illegal.
 350   // This iteration uses a pointer internal to the out array.
 351   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 352     Node** out = _out;
 353     // Assign a limit pointer to the reference argument:
 354     max = out + (ptrdiff_t)_outcnt;
 355     // Return the base pointer:
 356     return out;
 357   }
 358   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 359   // Iterate over the out-edges of this node, deleting one at a time.
 360   // This iteration uses a pointer internal to the out array.
 361   DUIterator_Last last_outs(DUIterator_Last& min) const {
 362     Node** out = _out;
 363     // Assign a limit pointer to the reference argument:
 364     min = out;
 365     // Return the pointer to the start of the iteration:
 366     return out + (ptrdiff_t)_outcnt - 1;
 367   }
 368   Node*    last_out(DUIterator_Last i) const  { return *i; }
 369 #endif
 370 
 371   // Reference to the i'th input Node.  Error if out of bounds.
 372   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 373   // Reference to the i'th input Node.  NULL if out of bounds.
 374   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : NULL); }
 375   // Reference to the i'th output Node.  Error if out of bounds.
 376   // Use this accessor sparingly.  We are going trying to use iterators instead.
 377   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 378   // Return the unique out edge.
 379   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 380   // Delete out edge at position 'i' by moving last out edge to position 'i'
 381   void  raw_del_out(uint i) {
 382     assert(i < _outcnt,"oob");
 383     assert(_outcnt > 0,"oob");
 384     #if OPTO_DU_ITERATOR_ASSERT
 385     // Record that a change happened here.
 386     debug_only(_last_del = _out[i]; ++_del_tick);
 387     #endif
 388     _out[i] = _out[--_outcnt];
 389     // Smash the old edge so it can't be used accidentally.
 390     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 391   }
 392 
 393 #ifdef ASSERT
 394   bool is_dead() const;
 395 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 396 #endif
 397   // Check whether node has become unreachable
 398   bool is_unreachable(PhaseIterGVN &igvn) const;
 399 
 400   // Set a required input edge, also updates corresponding output edge
 401   void add_req( Node *n ); // Append a NEW required input
 402   void add_req( Node *n0, Node *n1 ) {
 403     add_req(n0); add_req(n1); }
 404   void add_req( Node *n0, Node *n1, Node *n2 ) {
 405     add_req(n0); add_req(n1); add_req(n2); }
 406   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 407   void del_req( uint idx ); // Delete required edge & compact
 408   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 409   void ins_req( uint i, Node *n ); // Insert a NEW required input
 410   void set_req( uint i, Node *n ) {
 411     assert( is_not_dead(n), "can not use dead node");
 412     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 413     assert( !VerifyHashTableKeys || _hash_lock == 0,
 414             "remove node from hash table before modifying it");
 415     Node** p = &_in[i];    // cache this._in, across the del_out call
 416     if (*p != NULL)  (*p)->del_out((Node *)this);
 417     (*p) = n;
 418     if (n != NULL)      n->add_out((Node *)this);
 419     Compile::current()->record_modified_node(this);
 420   }
 421   // Light version of set_req() to init inputs after node creation.
 422   void init_req( uint i, Node *n ) {
 423     assert( i == 0 && this == n ||
 424             is_not_dead(n), "can not use dead node");
 425     assert( i < _cnt, "oob");
 426     assert( !VerifyHashTableKeys || _hash_lock == 0,
 427             "remove node from hash table before modifying it");
 428     assert( _in[i] == NULL, "sanity");
 429     _in[i] = n;
 430     if (n != NULL)      n->add_out((Node *)this);
 431     Compile::current()->record_modified_node(this);
 432   }
 433   // Find first occurrence of n among my edges:
 434   int find_edge(Node* n);
 435   int find_prec_edge(Node* n) {
 436     for (uint i = req(); i < len(); i++) {
 437       if (_in[i] == n) return i;
 438       if (_in[i] == NULL) {
 439         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == NULL, "Gap in prec edges!"); )
 440         break;
 441       }
 442     }
 443     return -1;
 444   }
 445   int replace_edge(Node* old, Node* neww);
 446   int replace_edges_in_range(Node* old, Node* neww, int start, int end);
 447   // NULL out all inputs to eliminate incoming Def-Use edges.
 448   // Return the number of edges between 'n' and 'this'
 449   int  disconnect_inputs(Node *n, Compile *c);
 450 
 451   // Quickly, return true if and only if I am Compile::current()->top().
 452   bool is_top() const {
 453     assert((this == (Node*) Compile::current()->top()) == (_out == NULL), "");
 454     return (_out == NULL);
 455   }
 456   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 457   void setup_is_top();
 458 
 459   // Strip away casting.  (It is depth-limited.)
 460   Node* uncast(bool keep_deps = false) const;
 461   // Return whether two Nodes are equivalent, after stripping casting.
 462   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 463     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 464   }
 465 
 466   // Find out of current node that matches opcode.
 467   Node* find_out_with(int opcode);
 468   // Return true if the current node has an out that matches opcode.
 469   bool has_out_with(int opcode);
 470   // Return true if the current node has an out that matches any of the opcodes.
 471   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 472 
 473 private:
 474   static Node* uncast_helper(const Node* n, bool keep_deps);
 475 
 476   // Add an output edge to the end of the list
 477   void add_out( Node *n ) {
 478     if (is_top())  return;
 479     if( _outcnt == _outmax ) out_grow(_outcnt);
 480     _out[_outcnt++] = n;
 481   }
 482   // Delete an output edge
 483   void del_out( Node *n ) {
 484     if (is_top())  return;
 485     Node** outp = &_out[_outcnt];
 486     // Find and remove n
 487     do {
 488       assert(outp > _out, "Missing Def-Use edge");
 489     } while (*--outp != n);
 490     *outp = _out[--_outcnt];
 491     // Smash the old edge so it can't be used accidentally.
 492     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 493     // Record that a change happened here.
 494     #if OPTO_DU_ITERATOR_ASSERT
 495     debug_only(_last_del = n; ++_del_tick);
 496     #endif
 497   }
 498   // Close gap after removing edge.
 499   void close_prec_gap_at(uint gap) {
 500     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 501     uint i = gap;
 502     Node *last = NULL;
 503     for (; i < _max-1; ++i) {
 504       Node *next = _in[i+1];
 505       if (next == NULL) break;
 506       last = next;
 507     }
 508     _in[gap] = last; // Move last slot to empty one.
 509     _in[i] = NULL;   // NULL out last slot.
 510   }
 511 
 512 public:
 513   // Globally replace this node by a given new node, updating all uses.
 514   void replace_by(Node* new_node);
 515   // Globally replace this node by a given new node, updating all uses
 516   // and cutting input edges of old node.
 517   void subsume_by(Node* new_node, Compile* c) {
 518     replace_by(new_node);
 519     disconnect_inputs(NULL, c);
 520   }
 521   void set_req_X( uint i, Node *n, PhaseIterGVN *igvn );
 522   // Find the one non-null required input.  RegionNode only
 523   Node *nonnull_req() const;
 524   // Add or remove precedence edges
 525   void add_prec( Node *n );
 526   void rm_prec( uint i );
 527 
 528   // Note: prec(i) will not necessarily point to n if edge already exists.
 529   void set_prec( uint i, Node *n ) {
 530     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 531     assert(is_not_dead(n), "can not use dead node");
 532     assert(i >= _cnt, "not a precedence edge");
 533     // Avoid spec violation: duplicated prec edge.
 534     if (_in[i] == n) return;
 535     if (n == NULL || find_prec_edge(n) != -1) {
 536       rm_prec(i);
 537       return;
 538     }
 539     if (_in[i] != NULL) _in[i]->del_out((Node *)this);
 540     _in[i] = n;
 541     if (n != NULL) n->add_out((Node *)this);
 542   }
 543 
 544   // Set this node's index, used by cisc_version to replace current node
 545   void set_idx(uint new_idx) {
 546     const node_idx_t* ref = &_idx;
 547     *(node_idx_t*)ref = new_idx;
 548   }
 549   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 550   void swap_edges(uint i1, uint i2) {
 551     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 552     // Def-Use info is unchanged
 553     Node* n1 = in(i1);
 554     Node* n2 = in(i2);
 555     _in[i1] = n2;
 556     _in[i2] = n1;
 557     // If this node is in the hash table, make sure it doesn't need a rehash.
 558     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 559   }
 560 
 561   // Iterators over input Nodes for a Node X are written as:
 562   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 563   // NOTE: Required edges can contain embedded NULL pointers.
 564 
 565 //----------------- Other Node Properties
 566 
 567   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 568   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 569   //
 570   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 571   // the type of the node the ID represents; another subset of an ID's bits are reserved
 572   // for the superclasses of the node represented by the ID.
 573   //
 574   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 575   // returns false. A.is_A() returns true.
 576   //
 577   // If two classes, A and B, have the same superclass, a different bit of A's class id
 578   // is reserved for A's type than for B's type. That bit is specified by the third
 579   // parameter in the macro DEFINE_CLASS_ID.
 580   //
 581   // By convention, classes with deeper hierarchy are declared first. Moreover,
 582   // classes with the same hierarchy depth are sorted by usage frequency.
 583   //
 584   // The query method masks the bits to cut off bits of subclasses and then compares
 585   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 586   //
 587   //  Class_MachCall=30, ClassMask_MachCall=31
 588   // 12               8               4               0
 589   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 590   //                                  |   |   |   |
 591   //                                  |   |   |   Bit_Mach=2
 592   //                                  |   |   Bit_MachReturn=4
 593   //                                  |   Bit_MachSafePoint=8
 594   //                                  Bit_MachCall=16
 595   //
 596   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 597   // 12               8               4               0
 598   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 599   //                              |   |   |
 600   //                              |   |   Bit_Region=8
 601   //                              |   Bit_Loop=16
 602   //                              Bit_CountedLoop=32
 603 
 604   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 605   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 606   Class_##cl = Class_##supcl + Bit_##cl , \
 607   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 608 
 609   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 610   // so that it's values fits into 16 bits.
 611   enum NodeClasses {
 612     Bit_Node   = 0x0000,
 613     Class_Node = 0x0000,
 614     ClassMask_Node = 0xFFFF,
 615 
 616     DEFINE_CLASS_ID(Multi, Node, 0)
 617       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 618         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 619           DEFINE_CLASS_ID(CallJava,         Call, 0)
 620             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 621             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 622           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 623             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 624           DEFINE_CLASS_ID(Allocate,         Call, 2)
 625             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 626           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 627             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 628             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 629           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 630       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 631         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 632           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 633           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 634         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 635           DEFINE_CLASS_ID(CountedLoopEnd,         If, 0)
 636           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 637           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 638         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 639       DEFINE_CLASS_ID(Start,       Multi, 2)
 640       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 641         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 642         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 643       DEFINE_CLASS_ID(LoadBarrier, Multi, 4)
 644 
 645     DEFINE_CLASS_ID(Mach,  Node, 1)
 646       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 647         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 648           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 649             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 650               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 651               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 652             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 653               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 654       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 655         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 656         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 657         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 658       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 659       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 660       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 661       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 662         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 663       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 664       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 665 
 666     DEFINE_CLASS_ID(Type,  Node, 2)
 667       DEFINE_CLASS_ID(Phi,   Type, 0)
 668       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 669         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 670         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 671       DEFINE_CLASS_ID(CMove, Type, 3)
 672       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 673       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 674         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 675         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 676       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 677         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 678         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 679       DEFINE_CLASS_ID(LoadBarrierSlowReg, Type, 7)
 680 
 681     DEFINE_CLASS_ID(Proj,  Node, 3)
 682       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 683       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 684       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 685         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 686         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 687       DEFINE_CLASS_ID(Parm,      Proj, 4)
 688       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 689 
 690     DEFINE_CLASS_ID(Mem,   Node, 4)
 691       DEFINE_CLASS_ID(Load,  Mem, 0)
 692         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 693       DEFINE_CLASS_ID(Store, Mem, 1)
 694         DEFINE_CLASS_ID(StoreVector, Store, 0)
 695       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 696         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 697           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 698         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 699 
 700     DEFINE_CLASS_ID(Region, Node, 5)
 701       DEFINE_CLASS_ID(Loop, Region, 0)
 702         DEFINE_CLASS_ID(Root,                Loop, 0)
 703         DEFINE_CLASS_ID(CountedLoop,         Loop, 1)
 704         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 705 
 706     DEFINE_CLASS_ID(Sub,   Node, 6)
 707       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 708         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 709         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 710 
 711     DEFINE_CLASS_ID(MergeMem, Node, 7)
 712     DEFINE_CLASS_ID(Bool,     Node, 8)
 713     DEFINE_CLASS_ID(AddP,     Node, 9)
 714     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 715     DEFINE_CLASS_ID(Add,      Node, 11)
 716     DEFINE_CLASS_ID(Mul,      Node, 12)
 717     DEFINE_CLASS_ID(Vector,   Node, 13)
 718     DEFINE_CLASS_ID(ClearArray, Node, 14)
 719     DEFINE_CLASS_ID(GetFP,    Node, 15)
 720 
 721     _max_classes  = ClassMask_ClearArray
 722   };
 723   #undef DEFINE_CLASS_ID
 724 
 725   // Flags are sorted by usage frequency.
 726   enum NodeFlags {
 727     Flag_is_Copy                     = 0x01, // should be first bit to avoid shift
 728     Flag_rematerialize               = Flag_is_Copy << 1,
 729     Flag_needs_anti_dependence_check = Flag_rematerialize << 1,
 730     Flag_is_macro                    = Flag_needs_anti_dependence_check << 1,
 731     Flag_is_Con                      = Flag_is_macro << 1,
 732     Flag_is_cisc_alternate           = Flag_is_Con << 1,
 733     Flag_is_dead_loop_safe           = Flag_is_cisc_alternate << 1,
 734     Flag_may_be_short_branch         = Flag_is_dead_loop_safe << 1,
 735     Flag_avoid_back_to_back_before   = Flag_may_be_short_branch << 1,
 736     Flag_avoid_back_to_back_after    = Flag_avoid_back_to_back_before << 1,
 737     Flag_has_call                    = Flag_avoid_back_to_back_after << 1,
 738     Flag_is_reduction                = Flag_has_call << 1,
 739     Flag_is_scheduled                = Flag_is_reduction << 1,
 740     Flag_has_vector_mask_set         = Flag_is_scheduled << 1,
 741     Flag_is_expensive                = Flag_has_vector_mask_set << 1,
 742     _max_flags = (Flag_is_expensive << 1) - 1 // allow flags combination
 743   };
 744 
 745 private:
 746   jushort _class_id;
 747   jushort _flags;
 748 
 749 protected:
 750   // These methods should be called from constructors only.
 751   void init_class_id(jushort c) {
 752     assert(c <= _max_classes, "invalid node class");
 753     _class_id = c; // cast out const
 754   }
 755   void init_flags(jushort fl) {
 756     assert(fl <= _max_flags, "invalid node flag");
 757     _flags |= fl;
 758   }
 759   void clear_flag(jushort fl) {
 760     assert(fl <= _max_flags, "invalid node flag");
 761     _flags &= ~fl;
 762   }
 763 
 764 public:
 765   const jushort class_id() const { return _class_id; }
 766 
 767   const jushort flags() const { return _flags; }
 768 
 769   void add_flag(jushort fl) { init_flags(fl); }
 770 
 771   void remove_flag(jushort fl) { clear_flag(fl); }
 772 
 773   // Return a dense integer opcode number
 774   virtual int Opcode() const;
 775 
 776   // Virtual inherited Node size
 777   virtual uint size_of() const;
 778 
 779   // Other interesting Node properties
 780   #define DEFINE_CLASS_QUERY(type)                           \
 781   bool is_##type() const {                                   \
 782     return ((_class_id & ClassMask_##type) == Class_##type); \
 783   }                                                          \
 784   type##Node *as_##type() const {                            \
 785     assert(is_##type(), "invalid node class");               \
 786     return (type##Node*)this;                                \
 787   }                                                          \
 788   type##Node* isa_##type() const {                           \
 789     return (is_##type()) ? as_##type() : NULL;               \
 790   }
 791 
 792   DEFINE_CLASS_QUERY(AbstractLock)
 793   DEFINE_CLASS_QUERY(Add)
 794   DEFINE_CLASS_QUERY(AddP)
 795   DEFINE_CLASS_QUERY(Allocate)
 796   DEFINE_CLASS_QUERY(AllocateArray)
 797   DEFINE_CLASS_QUERY(ArrayCopy)
 798   DEFINE_CLASS_QUERY(Bool)
 799   DEFINE_CLASS_QUERY(BoxLock)
 800   DEFINE_CLASS_QUERY(Call)
 801   DEFINE_CLASS_QUERY(CallDynamicJava)
 802   DEFINE_CLASS_QUERY(CallJava)
 803   DEFINE_CLASS_QUERY(CallLeaf)
 804   DEFINE_CLASS_QUERY(CallRuntime)
 805   DEFINE_CLASS_QUERY(CallStaticJava)
 806   DEFINE_CLASS_QUERY(Catch)
 807   DEFINE_CLASS_QUERY(CatchProj)
 808   DEFINE_CLASS_QUERY(CheckCastPP)
 809   DEFINE_CLASS_QUERY(CastII)
 810   DEFINE_CLASS_QUERY(ConstraintCast)
 811   DEFINE_CLASS_QUERY(ClearArray)
 812   DEFINE_CLASS_QUERY(CMove)
 813   DEFINE_CLASS_QUERY(Cmp)
 814   DEFINE_CLASS_QUERY(CountedLoop)
 815   DEFINE_CLASS_QUERY(CountedLoopEnd)
 816   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 817   DEFINE_CLASS_QUERY(DecodeN)
 818   DEFINE_CLASS_QUERY(DecodeNKlass)
 819   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 820   DEFINE_CLASS_QUERY(EncodeP)
 821   DEFINE_CLASS_QUERY(EncodePKlass)
 822   DEFINE_CLASS_QUERY(FastLock)
 823   DEFINE_CLASS_QUERY(FastUnlock)
 824   DEFINE_CLASS_QUERY(If)
 825   DEFINE_CLASS_QUERY(RangeCheck)
 826   DEFINE_CLASS_QUERY(IfProj)
 827   DEFINE_CLASS_QUERY(IfFalse)
 828   DEFINE_CLASS_QUERY(IfTrue)
 829   DEFINE_CLASS_QUERY(Initialize)
 830   DEFINE_CLASS_QUERY(Jump)
 831   DEFINE_CLASS_QUERY(JumpProj)
 832   DEFINE_CLASS_QUERY(Load)
 833   DEFINE_CLASS_QUERY(LoadStore)
 834   DEFINE_CLASS_QUERY(LoadStoreConditional)
 835   DEFINE_CLASS_QUERY(LoadBarrier)
 836   DEFINE_CLASS_QUERY(LoadBarrierSlowReg)
 837   DEFINE_CLASS_QUERY(Lock)
 838   DEFINE_CLASS_QUERY(Loop)
 839   DEFINE_CLASS_QUERY(Mach)
 840   DEFINE_CLASS_QUERY(MachBranch)
 841   DEFINE_CLASS_QUERY(MachCall)
 842   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 843   DEFINE_CLASS_QUERY(MachCallJava)
 844   DEFINE_CLASS_QUERY(MachCallLeaf)
 845   DEFINE_CLASS_QUERY(MachCallRuntime)
 846   DEFINE_CLASS_QUERY(MachCallStaticJava)
 847   DEFINE_CLASS_QUERY(MachConstantBase)
 848   DEFINE_CLASS_QUERY(MachConstant)
 849   DEFINE_CLASS_QUERY(MachGoto)
 850   DEFINE_CLASS_QUERY(MachIf)
 851   DEFINE_CLASS_QUERY(MachJump)
 852   DEFINE_CLASS_QUERY(MachNullCheck)
 853   DEFINE_CLASS_QUERY(MachProj)
 854   DEFINE_CLASS_QUERY(MachReturn)
 855   DEFINE_CLASS_QUERY(MachSafePoint)
 856   DEFINE_CLASS_QUERY(MachSpillCopy)
 857   DEFINE_CLASS_QUERY(MachTemp)
 858   DEFINE_CLASS_QUERY(MachMemBar)
 859   DEFINE_CLASS_QUERY(MachMerge)
 860   DEFINE_CLASS_QUERY(Mem)
 861   DEFINE_CLASS_QUERY(MemBar)
 862   DEFINE_CLASS_QUERY(MemBarStoreStore)
 863   DEFINE_CLASS_QUERY(MergeMem)
 864   DEFINE_CLASS_QUERY(Mul)
 865   DEFINE_CLASS_QUERY(Multi)
 866   DEFINE_CLASS_QUERY(MultiBranch)
 867   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 868   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 869   DEFINE_CLASS_QUERY(Parm)
 870   DEFINE_CLASS_QUERY(PCTable)
 871   DEFINE_CLASS_QUERY(Phi)
 872   DEFINE_CLASS_QUERY(Proj)
 873   DEFINE_CLASS_QUERY(Region)
 874   DEFINE_CLASS_QUERY(Root)
 875   DEFINE_CLASS_QUERY(SafePoint)
 876   DEFINE_CLASS_QUERY(SafePointScalarObject)
 877   DEFINE_CLASS_QUERY(Start)
 878   DEFINE_CLASS_QUERY(Store)
 879   DEFINE_CLASS_QUERY(Sub)
 880   DEFINE_CLASS_QUERY(Type)
 881   DEFINE_CLASS_QUERY(Vector)
 882   DEFINE_CLASS_QUERY(LoadVector)
 883   DEFINE_CLASS_QUERY(StoreVector)
 884   DEFINE_CLASS_QUERY(Unlock)
 885 
 886   #undef DEFINE_CLASS_QUERY
 887 
 888   // duplicate of is_MachSpillCopy()
 889   bool is_SpillCopy () const {
 890     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 891   }
 892 
 893   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 894   // The data node which is safe to leave in dead loop during IGVN optimization.
 895   bool is_dead_loop_safe() const {
 896     return is_Phi() || (is_Proj() && in(0) == NULL) ||
 897            ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0 &&
 898             (!is_Proj() || !in(0)->is_Allocate()));
 899   }
 900 
 901   // is_Copy() returns copied edge index (0 or 1)
 902   uint is_Copy() const { return (_flags & Flag_is_Copy); }
 903 
 904   virtual bool is_CFG() const { return false; }
 905 
 906   // If this node is control-dependent on a test, can it be
 907   // rerouted to a dominating equivalent test?  This is usually
 908   // true of non-CFG nodes, but can be false for operations which
 909   // depend for their correct sequencing on more than one test.
 910   // (In that case, hoisting to a dominating test may silently
 911   // skip some other important test.)
 912   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
 913 
 914   // When building basic blocks, I need to have a notion of block beginning
 915   // Nodes, next block selector Nodes (block enders), and next block
 916   // projections.  These calls need to work on their machine equivalents.  The
 917   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
 918   bool is_block_start() const {
 919     if ( is_Region() )
 920       return this == (const Node*)in(0);
 921     else
 922       return is_Start();
 923   }
 924 
 925   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
 926   // Goto and Return.  This call also returns the block ending Node.
 927   virtual const Node *is_block_proj() const;
 928 
 929   // The node is a "macro" node which needs to be expanded before matching
 930   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
 931   // The node is expensive: the best control is set during loop opts
 932   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != NULL; }
 933 
 934   // An arithmetic node which accumulates a data in a loop.
 935   // It must have the loop's phi as input and provide a def to the phi.
 936   bool is_reduction() const { return (_flags & Flag_is_reduction) != 0; }
 937 
 938   // The node is a CountedLoopEnd with a mask annotation so as to emit a restore context
 939   bool has_vector_mask_set() const { return (_flags & Flag_has_vector_mask_set) != 0; }
 940 
 941   // Used in lcm to mark nodes that have scheduled
 942   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
 943 
 944 //----------------- Optimization
 945 
 946   // Get the worst-case Type output for this Node.
 947   virtual const class Type *bottom_type() const;
 948 
 949   // If we find a better type for a node, try to record it permanently.
 950   // Return true if this node actually changed.
 951   // Be sure to do the hash_delete game in the "rehash" variant.
 952   void raise_bottom_type(const Type* new_type);
 953 
 954   // Get the address type with which this node uses and/or defs memory,
 955   // or NULL if none.  The address type is conservatively wide.
 956   // Returns non-null for calls, membars, loads, stores, etc.
 957   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
 958   virtual const class TypePtr *adr_type() const { return NULL; }
 959 
 960   // Return an existing node which computes the same function as this node.
 961   // The optimistic combined algorithm requires this to return a Node which
 962   // is a small number of steps away (e.g., one of my inputs).
 963   virtual Node* Identity(PhaseGVN* phase);
 964 
 965   // Return the set of values this Node can take on at runtime.
 966   virtual const Type* Value(PhaseGVN* phase) const;
 967 
 968   // Return a node which is more "ideal" than the current node.
 969   // The invariants on this call are subtle.  If in doubt, read the
 970   // treatise in node.cpp above the default implemention AND TEST WITH
 971   // +VerifyIterativeGVN!
 972   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 973 
 974   // Some nodes have specific Ideal subgraph transformations only if they are
 975   // unique users of specific nodes. Such nodes should be put on IGVN worklist
 976   // for the transformations to happen.
 977   bool has_special_unique_user() const;
 978 
 979   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
 980   Node* find_exact_control(Node* ctrl);
 981 
 982   // Check if 'this' node dominates or equal to 'sub'.
 983   bool dominates(Node* sub, Node_List &nlist);
 984 
 985 protected:
 986   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
 987 public:
 988 
 989   // See if there is valid pipeline info
 990   static  const Pipeline *pipeline_class();
 991   virtual const Pipeline *pipeline() const;
 992 
 993   // Compute the latency from the def to this instruction of the ith input node
 994   uint latency(uint i);
 995 
 996   // Hash & compare functions, for pessimistic value numbering
 997 
 998   // If the hash function returns the special sentinel value NO_HASH,
 999   // the node is guaranteed never to compare equal to any other node.
1000   // If we accidentally generate a hash with value NO_HASH the node
1001   // won't go into the table and we'll lose a little optimization.
1002   static const uint NO_HASH = 0;
1003   virtual uint hash() const;
1004   virtual bool cmp( const Node &n ) const;
1005 
1006   // Operation appears to be iteratively computed (such as an induction variable)
1007   // It is possible for this operation to return false for a loop-varying
1008   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1009   bool is_iteratively_computed();
1010 
1011   // Determine if a node is a counted loop induction variable.
1012   // NOTE: The method is defined in "loopnode.cpp".
1013   bool is_cloop_ind_var() const;
1014 
1015   // Return a node with opcode "opc" and same inputs as "this" if one can
1016   // be found; Otherwise return NULL;
1017   Node* find_similar(int opc);
1018 
1019   // Return the unique control out if only one. Null if none or more than one.
1020   Node* unique_ctrl_out() const;
1021 
1022   // Set control or add control as precedence edge
1023   void ensure_control_or_add_prec(Node* c);
1024 
1025 //----------------- Code Generation
1026 
1027   // Ideal register class for Matching.  Zero means unmatched instruction
1028   // (these are cloned instead of converted to machine nodes).
1029   virtual uint ideal_reg() const;
1030 
1031   static const uint NotAMachineReg;   // must be > max. machine register
1032 
1033   // Do we Match on this edge index or not?  Generally false for Control
1034   // and true for everything else.  Weird for calls & returns.
1035   virtual uint match_edge(uint idx) const;
1036 
1037   // Register class output is returned in
1038   virtual const RegMask &out_RegMask() const;
1039   // Register class input is expected in
1040   virtual const RegMask &in_RegMask(uint) const;
1041   // Should we clone rather than spill this instruction?
1042   bool rematerialize() const;
1043 
1044   // Return JVM State Object if this Node carries debug info, or NULL otherwise
1045   virtual JVMState* jvms() const;
1046 
1047   // Print as assembly
1048   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1049   // Emit bytes starting at parameter 'ptr'
1050   // Bump 'ptr' by the number of output bytes
1051   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1052   // Size of instruction in bytes
1053   virtual uint size(PhaseRegAlloc *ra_) const;
1054 
1055   // Convenience function to extract an integer constant from a node.
1056   // If it is not an integer constant (either Con, CastII, or Mach),
1057   // return value_if_unknown.
1058   jint find_int_con(jint value_if_unknown) const {
1059     const TypeInt* t = find_int_type();
1060     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1061   }
1062   // Return the constant, knowing it is an integer constant already
1063   jint get_int() const {
1064     const TypeInt* t = find_int_type();
1065     guarantee(t != NULL, "must be con");
1066     return t->get_con();
1067   }
1068   // Here's where the work is done.  Can produce non-constant int types too.
1069   const TypeInt* find_int_type() const;
1070 
1071   // Same thing for long (and intptr_t, via type.hpp):
1072   jlong get_long() const {
1073     const TypeLong* t = find_long_type();
1074     guarantee(t != NULL, "must be con");
1075     return t->get_con();
1076   }
1077   jlong find_long_con(jint value_if_unknown) const {
1078     const TypeLong* t = find_long_type();
1079     return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
1080   }
1081   const TypeLong* find_long_type() const;
1082 
1083   const TypePtr* get_ptr_type() const;
1084 
1085   // These guys are called by code generated by ADLC:
1086   intptr_t get_ptr() const;
1087   intptr_t get_narrowcon() const;
1088   jdouble getd() const;
1089   jfloat getf() const;
1090 
1091   // Nodes which are pinned into basic blocks
1092   virtual bool pinned() const { return false; }
1093 
1094   // Nodes which use memory without consuming it, hence need antidependences
1095   // More specifically, needs_anti_dependence_check returns true iff the node
1096   // (a) does a load, and (b) does not perform a store (except perhaps to a
1097   // stack slot or some other unaliased location).
1098   bool needs_anti_dependence_check() const;
1099 
1100   // Return which operand this instruction may cisc-spill. In other words,
1101   // return operand position that can convert from reg to memory access
1102   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1103   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1104 
1105 //----------------- Graph walking
1106 public:
1107   // Walk and apply member functions recursively.
1108   // Supplied (this) pointer is root.
1109   void walk(NFunc pre, NFunc post, void *env);
1110   static void nop(Node &, void*); // Dummy empty function
1111   static void packregion( Node &n, void* );
1112 private:
1113   void walk_(NFunc pre, NFunc post, void *env, VectorSet &visited);
1114 
1115 //----------------- Printing, etc
1116 public:
1117 #ifndef PRODUCT
1118   Node* find(int idx) const;         // Search the graph for the given idx.
1119   Node* find_ctrl(int idx) const;    // Search control ancestors for the given idx.
1120   void dump() const { dump("\n"); }  // Print this node.
1121   void dump(const char* suffix, bool mark = false, outputStream *st = tty) const; // Print this node.
1122   void dump(int depth) const;        // Print this node, recursively to depth d
1123   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1124   void dump_comp() const;            // Print this node in compact representation.
1125   // Print this node in compact representation.
1126   void dump_comp(const char* suffix, outputStream *st = tty) const;
1127   virtual void dump_req(outputStream *st = tty) const;    // Print required-edge info
1128   virtual void dump_prec(outputStream *st = tty) const;   // Print precedence-edge info
1129   virtual void dump_out(outputStream *st = tty) const;    // Print the output edge info
1130   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1131   // Print compact per-node info
1132   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1133   void dump_related() const;             // Print related nodes (depends on node at hand).
1134   // Print related nodes up to given depths for input and output nodes.
1135   void dump_related(uint d_in, uint d_out) const;
1136   void dump_related_compact() const;     // Print related nodes in compact representation.
1137   // Collect related nodes.
1138   virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;
1139   // Collect nodes starting from this node, explicitly including/excluding control and data links.
1140   void collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const;
1141 
1142   // Node collectors, to be used in implementations of Node::rel().
1143   // Collect the entire data input graph. Include control inputs if requested.
1144   void collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const;
1145   // Collect the entire control input graph. Include data inputs if requested.
1146   void collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const;
1147   // Collect the entire output graph until hitting and including control nodes.
1148   void collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const;
1149 
1150   void verify_edges(Unique_Node_List &visited); // Verify bi-directional edges
1151   void verify() const;               // Check Def-Use info for my subgraph
1152   static void verify_recur(const Node *n, int verify_depth, VectorSet &old_space, VectorSet &new_space);
1153 
1154   // This call defines a class-unique string used to identify class instances
1155   virtual const char *Name() const;
1156 
1157   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1158   // RegMask Print Functions
1159   void dump_in_regmask(int idx) { in_RegMask(idx).dump(); }
1160   void dump_out_regmask() { out_RegMask().dump(); }
1161   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; }
1162   void fast_dump() const {
1163     tty->print("%4d: %-17s", _idx, Name());
1164     for (uint i = 0; i < len(); i++)
1165       if (in(i))
1166         tty->print(" %4d", in(i)->_idx);
1167       else
1168         tty->print(" NULL");
1169     tty->print("\n");
1170   }
1171 #endif
1172 #ifdef ASSERT
1173   void verify_construction();
1174   bool verify_jvms(const JVMState* jvms) const;
1175   int  _debug_idx;                     // Unique value assigned to every node.
1176   int   debug_idx() const              { return _debug_idx; }
1177   void  set_debug_idx( int debug_idx ) { _debug_idx = debug_idx; }
1178 
1179   Node* _debug_orig;                   // Original version of this, if any.
1180   Node*  debug_orig() const            { return _debug_orig; }
1181   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1182 
1183   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1184   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1185   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1186 
1187   static void init_NodeProperty();
1188 
1189   #if OPTO_DU_ITERATOR_ASSERT
1190   const Node* _last_del;               // The last deleted node.
1191   uint        _del_tick;               // Bumped when a deletion happens..
1192   #endif
1193 #endif
1194 };
1195 
1196 
1197 #ifndef PRODUCT
1198 
1199 // Used in debugging code to avoid walking across dead or uninitialized edges.
1200 inline bool NotANode(const Node* n) {
1201   if (n == NULL)                   return true;
1202   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1203   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1204   return false;
1205 }
1206 
1207 #endif
1208 
1209 
1210 //-----------------------------------------------------------------------------
1211 // Iterators over DU info, and associated Node functions.
1212 
1213 #if OPTO_DU_ITERATOR_ASSERT
1214 
1215 // Common code for assertion checking on DU iterators.
1216 class DUIterator_Common {
1217 #ifdef ASSERT
1218  protected:
1219   bool         _vdui;               // cached value of VerifyDUIterators
1220   const Node*  _node;               // the node containing the _out array
1221   uint         _outcnt;             // cached node->_outcnt
1222   uint         _del_tick;           // cached node->_del_tick
1223   Node*        _last;               // last value produced by the iterator
1224 
1225   void sample(const Node* node);    // used by c'tor to set up for verifies
1226   void verify(const Node* node, bool at_end_ok = false);
1227   void verify_resync();
1228   void reset(const DUIterator_Common& that);
1229 
1230 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1231   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1232 #else
1233   #define I_VDUI_ONLY(i,x) { }
1234 #endif //ASSERT
1235 };
1236 
1237 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1238 
1239 // Default DU iterator.  Allows appends onto the out array.
1240 // Allows deletion from the out array only at the current point.
1241 // Usage:
1242 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1243 //    Node* y = x->out(i);
1244 //    ...
1245 //  }
1246 // Compiles in product mode to a unsigned integer index, which indexes
1247 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1248 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1249 // before continuing the loop.  You must delete only the last-produced
1250 // edge.  You must delete only a single copy of the last-produced edge,
1251 // or else you must delete all copies at once (the first time the edge
1252 // is produced by the iterator).
1253 class DUIterator : public DUIterator_Common {
1254   friend class Node;
1255 
1256   // This is the index which provides the product-mode behavior.
1257   // Whatever the product-mode version of the system does to the
1258   // DUI index is done to this index.  All other fields in
1259   // this class are used only for assertion checking.
1260   uint         _idx;
1261 
1262   #ifdef ASSERT
1263   uint         _refresh_tick;    // Records the refresh activity.
1264 
1265   void sample(const Node* node); // Initialize _refresh_tick etc.
1266   void verify(const Node* node, bool at_end_ok = false);
1267   void verify_increment();       // Verify an increment operation.
1268   void verify_resync();          // Verify that we can back up over a deletion.
1269   void verify_finish();          // Verify that the loop terminated properly.
1270   void refresh();                // Resample verification info.
1271   void reset(const DUIterator& that);  // Resample after assignment.
1272   #endif
1273 
1274   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1275     { _idx = 0;                         debug_only(sample(node)); }
1276 
1277  public:
1278   // initialize to garbage; clear _vdui to disable asserts
1279   DUIterator()
1280     { /*initialize to garbage*/         debug_only(_vdui = false); }
1281 
1282   void operator++(int dummy_to_specify_postfix_op)
1283     { _idx++;                           VDUI_ONLY(verify_increment()); }
1284 
1285   void operator--()
1286     { VDUI_ONLY(verify_resync());       --_idx; }
1287 
1288   ~DUIterator()
1289     { VDUI_ONLY(verify_finish()); }
1290 
1291   void operator=(const DUIterator& that)
1292     { _idx = that._idx;                 debug_only(reset(that)); }
1293 };
1294 
1295 DUIterator Node::outs() const
1296   { return DUIterator(this, 0); }
1297 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1298   { I_VDUI_ONLY(i, i.refresh());        return i; }
1299 bool Node::has_out(DUIterator& i) const
1300   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1301 Node*    Node::out(DUIterator& i) const
1302   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1303 
1304 
1305 // Faster DU iterator.  Disallows insertions into the out array.
1306 // Allows deletion from the out array only at the current point.
1307 // Usage:
1308 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1309 //    Node* y = x->fast_out(i);
1310 //    ...
1311 //  }
1312 // Compiles in product mode to raw Node** pointer arithmetic, with
1313 // no reloading of pointers from the original node x.  If you delete,
1314 // you must perform "--i; --imax" just before continuing the loop.
1315 // If you delete multiple copies of the same edge, you must decrement
1316 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1317 class DUIterator_Fast : public DUIterator_Common {
1318   friend class Node;
1319   friend class DUIterator_Last;
1320 
1321   // This is the pointer which provides the product-mode behavior.
1322   // Whatever the product-mode version of the system does to the
1323   // DUI pointer is done to this pointer.  All other fields in
1324   // this class are used only for assertion checking.
1325   Node**       _outp;
1326 
1327   #ifdef ASSERT
1328   void verify(const Node* node, bool at_end_ok = false);
1329   void verify_limit();
1330   void verify_resync();
1331   void verify_relimit(uint n);
1332   void reset(const DUIterator_Fast& that);
1333   #endif
1334 
1335   // Note:  offset must be signed, since -1 is sometimes passed
1336   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1337     { _outp = node->_out + offset;      debug_only(sample(node)); }
1338 
1339  public:
1340   // initialize to garbage; clear _vdui to disable asserts
1341   DUIterator_Fast()
1342     { /*initialize to garbage*/         debug_only(_vdui = false); }
1343 
1344   void operator++(int dummy_to_specify_postfix_op)
1345     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1346 
1347   void operator--()
1348     { VDUI_ONLY(verify_resync());       --_outp; }
1349 
1350   void operator-=(uint n)   // applied to the limit only
1351     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1352 
1353   bool operator<(DUIterator_Fast& limit) {
1354     I_VDUI_ONLY(*this, this->verify(_node, true));
1355     I_VDUI_ONLY(limit, limit.verify_limit());
1356     return _outp < limit._outp;
1357   }
1358 
1359   void operator=(const DUIterator_Fast& that)
1360     { _outp = that._outp;               debug_only(reset(that)); }
1361 };
1362 
1363 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1364   // Assign a limit pointer to the reference argument:
1365   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1366   // Return the base pointer:
1367   return DUIterator_Fast(this, 0);
1368 }
1369 Node* Node::fast_out(DUIterator_Fast& i) const {
1370   I_VDUI_ONLY(i, i.verify(this));
1371   return debug_only(i._last=) *i._outp;
1372 }
1373 
1374 
1375 // Faster DU iterator.  Requires each successive edge to be removed.
1376 // Does not allow insertion of any edges.
1377 // Usage:
1378 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1379 //    Node* y = x->last_out(i);
1380 //    ...
1381 //  }
1382 // Compiles in product mode to raw Node** pointer arithmetic, with
1383 // no reloading of pointers from the original node x.
1384 class DUIterator_Last : private DUIterator_Fast {
1385   friend class Node;
1386 
1387   #ifdef ASSERT
1388   void verify(const Node* node, bool at_end_ok = false);
1389   void verify_limit();
1390   void verify_step(uint num_edges);
1391   #endif
1392 
1393   // Note:  offset must be signed, since -1 is sometimes passed
1394   DUIterator_Last(const Node* node, ptrdiff_t offset)
1395     : DUIterator_Fast(node, offset) { }
1396 
1397   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1398   void operator<(int)                              {} // do not use
1399 
1400  public:
1401   DUIterator_Last() { }
1402   // initialize to garbage
1403 
1404   void operator--()
1405     { _outp--;              VDUI_ONLY(verify_step(1));  }
1406 
1407   void operator-=(uint n)
1408     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1409 
1410   bool operator>=(DUIterator_Last& limit) {
1411     I_VDUI_ONLY(*this, this->verify(_node, true));
1412     I_VDUI_ONLY(limit, limit.verify_limit());
1413     return _outp >= limit._outp;
1414   }
1415 
1416   void operator=(const DUIterator_Last& that)
1417     { DUIterator_Fast::operator=(that); }
1418 };
1419 
1420 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1421   // Assign a limit pointer to the reference argument:
1422   imin = DUIterator_Last(this, 0);
1423   // Return the initial pointer:
1424   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1425 }
1426 Node* Node::last_out(DUIterator_Last& i) const {
1427   I_VDUI_ONLY(i, i.verify(this));
1428   return debug_only(i._last=) *i._outp;
1429 }
1430 
1431 #endif //OPTO_DU_ITERATOR_ASSERT
1432 
1433 #undef I_VDUI_ONLY
1434 #undef VDUI_ONLY
1435 
1436 // An Iterator that truly follows the iterator pattern.  Doesn't
1437 // support deletion but could be made to.
1438 //
1439 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1440 //     Node* m = i.get();
1441 //
1442 class SimpleDUIterator : public StackObj {
1443  private:
1444   Node* node;
1445   DUIterator_Fast i;
1446   DUIterator_Fast imax;
1447  public:
1448   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1449   bool has_next() { return i < imax; }
1450   void next() { i++; }
1451   Node* get() { return node->fast_out(i); }
1452 };
1453 
1454 
1455 //-----------------------------------------------------------------------------
1456 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1457 // Abstractly provides an infinite array of Node*'s, initialized to NULL.
1458 // Note that the constructor just zeros things, and since I use Arena
1459 // allocation I do not need a destructor to reclaim storage.
1460 class Node_Array : public ResourceObj {
1461   friend class VMStructs;
1462 protected:
1463   Arena *_a;                    // Arena to allocate in
1464   uint   _max;
1465   Node **_nodes;
1466   void   grow( uint i );        // Grow array node to fit
1467 public:
1468   Node_Array(Arena *a) : _a(a), _max(OptoNodeListSize) {
1469     _nodes = NEW_ARENA_ARRAY( a, Node *, OptoNodeListSize );
1470     for( int i = 0; i < OptoNodeListSize; i++ ) {
1471       _nodes[i] = NULL;
1472     }
1473   }
1474 
1475   Node_Array(Node_Array *na) : _a(na->_a), _max(na->_max), _nodes(na->_nodes) {}
1476   Node *operator[] ( uint i ) const // Lookup, or NULL for not mapped
1477   { return (i<_max) ? _nodes[i] : (Node*)NULL; }
1478   Node *at( uint i ) const { assert(i<_max,"oob"); return _nodes[i]; }
1479   Node **adr() { return _nodes; }
1480   // Extend the mapping: index i maps to Node *n.
1481   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1482   void insert( uint i, Node *n );
1483   void remove( uint i );        // Remove, preserving order
1484   void sort( C_sort_func_t func);
1485   void reset( Arena *new_a );   // Zap mapping to empty; reclaim storage
1486   void clear();                 // Set all entries to NULL, keep storage
1487   uint Size() const { return _max; }
1488   void dump() const;
1489 };
1490 
1491 class Node_List : public Node_Array {
1492   friend class VMStructs;
1493   uint _cnt;
1494 public:
1495   Node_List() : Node_Array(Thread::current()->resource_area()), _cnt(0) {}
1496   Node_List(Arena *a) : Node_Array(a), _cnt(0) {}
1497   bool contains(const Node* n) const {
1498     for (uint e = 0; e < size(); e++) {
1499       if (at(e) == n) return true;
1500     }
1501     return false;
1502   }
1503   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1504   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1505   void push( Node *b ) { map(_cnt++,b); }
1506   void yank( Node *n );         // Find and remove
1507   Node *pop() { return _nodes[--_cnt]; }
1508   Node *rpop() { Node *b = _nodes[0]; _nodes[0]=_nodes[--_cnt]; return b;}
1509   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1510   uint size() const { return _cnt; }
1511   void dump() const;
1512   void dump_simple() const;
1513 };
1514 
1515 //------------------------------Unique_Node_List-------------------------------
1516 class Unique_Node_List : public Node_List {
1517   friend class VMStructs;
1518   VectorSet _in_worklist;
1519   uint _clock_index;            // Index in list where to pop from next
1520 public:
1521   Unique_Node_List() : Node_List(), _in_worklist(Thread::current()->resource_area()), _clock_index(0) {}
1522   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1523 
1524   void remove( Node *n );
1525   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1526   VectorSet &member_set(){ return _in_worklist; }
1527 
1528   void push( Node *b ) {
1529     if( !_in_worklist.test_set(b->_idx) )
1530       Node_List::push(b);
1531   }
1532   Node *pop() {
1533     if( _clock_index >= size() ) _clock_index = 0;
1534     Node *b = at(_clock_index);
1535     map( _clock_index, Node_List::pop());
1536     if (size() != 0) _clock_index++; // Always start from 0
1537     _in_worklist >>= b->_idx;
1538     return b;
1539   }
1540   Node *remove( uint i ) {
1541     Node *b = Node_List::at(i);
1542     _in_worklist >>= b->_idx;
1543     map(i,Node_List::pop());
1544     return b;
1545   }
1546   void yank( Node *n ) { _in_worklist >>= n->_idx; Node_List::yank(n); }
1547   void  clear() {
1548     _in_worklist.Clear();        // Discards storage but grows automatically
1549     Node_List::clear();
1550     _clock_index = 0;
1551   }
1552 
1553   // Used after parsing to remove useless nodes before Iterative GVN
1554   void remove_useless_nodes(VectorSet &useful);
1555 
1556 #ifndef PRODUCT
1557   void print_set() const { _in_worklist.print(); }
1558 #endif
1559 };
1560 
1561 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1562 inline void Compile::record_for_igvn(Node* n) {
1563   _for_igvn->push(n);
1564 }
1565 
1566 //------------------------------Node_Stack-------------------------------------
1567 class Node_Stack {
1568   friend class VMStructs;
1569 protected:
1570   struct INode {
1571     Node *node; // Processed node
1572     uint  indx; // Index of next node's child
1573   };
1574   INode *_inode_top; // tos, stack grows up
1575   INode *_inode_max; // End of _inodes == _inodes + _max
1576   INode *_inodes;    // Array storage for the stack
1577   Arena *_a;         // Arena to allocate in
1578   void grow();
1579 public:
1580   Node_Stack(int size) {
1581     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1582     _a = Thread::current()->resource_area();
1583     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1584     _inode_max = _inodes + max;
1585     _inode_top = _inodes - 1; // stack is empty
1586   }
1587 
1588   Node_Stack(Arena *a, int size) : _a(a) {
1589     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1590     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1591     _inode_max = _inodes + max;
1592     _inode_top = _inodes - 1; // stack is empty
1593   }
1594 
1595   void pop() {
1596     assert(_inode_top >= _inodes, "node stack underflow");
1597     --_inode_top;
1598   }
1599   void push(Node *n, uint i) {
1600     ++_inode_top;
1601     if (_inode_top >= _inode_max) grow();
1602     INode *top = _inode_top; // optimization
1603     top->node = n;
1604     top->indx = i;
1605   }
1606   Node *node() const {
1607     return _inode_top->node;
1608   }
1609   Node* node_at(uint i) const {
1610     assert(_inodes + i <= _inode_top, "in range");
1611     return _inodes[i].node;
1612   }
1613   uint index() const {
1614     return _inode_top->indx;
1615   }
1616   uint index_at(uint i) const {
1617     assert(_inodes + i <= _inode_top, "in range");
1618     return _inodes[i].indx;
1619   }
1620   void set_node(Node *n) {
1621     _inode_top->node = n;
1622   }
1623   void set_index(uint i) {
1624     _inode_top->indx = i;
1625   }
1626   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1627   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1628   bool is_nonempty() const { return (_inode_top >= _inodes); }
1629   bool is_empty() const { return (_inode_top < _inodes); }
1630   void clear() { _inode_top = _inodes - 1; } // retain storage
1631 
1632   // Node_Stack is used to map nodes.
1633   Node* find(uint idx) const;
1634 };
1635 
1636 
1637 //-----------------------------Node_Notes--------------------------------------
1638 // Debugging or profiling annotations loosely and sparsely associated
1639 // with some nodes.  See Compile::node_notes_at for the accessor.
1640 class Node_Notes {
1641   friend class VMStructs;
1642   JVMState* _jvms;
1643 
1644 public:
1645   Node_Notes(JVMState* jvms = NULL) {
1646     _jvms = jvms;
1647   }
1648 
1649   JVMState* jvms()            { return _jvms; }
1650   void  set_jvms(JVMState* x) {        _jvms = x; }
1651 
1652   // True if there is nothing here.
1653   bool is_clear() {
1654     return (_jvms == NULL);
1655   }
1656 
1657   // Make there be nothing here.
1658   void clear() {
1659     _jvms = NULL;
1660   }
1661 
1662   // Make a new, clean node notes.
1663   static Node_Notes* make(Compile* C) {
1664     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1665     nn->clear();
1666     return nn;
1667   }
1668 
1669   Node_Notes* clone(Compile* C) {
1670     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1671     (*nn) = (*this);
1672     return nn;
1673   }
1674 
1675   // Absorb any information from source.
1676   bool update_from(Node_Notes* source) {
1677     bool changed = false;
1678     if (source != NULL) {
1679       if (source->jvms() != NULL) {
1680         set_jvms(source->jvms());
1681         changed = true;
1682       }
1683     }
1684     return changed;
1685   }
1686 };
1687 
1688 // Inlined accessors for Compile::node_nodes that require the preceding class:
1689 inline Node_Notes*
1690 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1691                            int idx, bool can_grow) {
1692   assert(idx >= 0, "oob");
1693   int block_idx = (idx >> _log2_node_notes_block_size);
1694   int grow_by = (block_idx - (arr == NULL? 0: arr->length()));
1695   if (grow_by >= 0) {
1696     if (!can_grow) return NULL;
1697     grow_node_notes(arr, grow_by + 1);
1698   }
1699   if (arr == NULL) return NULL;
1700   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1701   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1702 }
1703 
1704 inline bool
1705 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1706   if (value == NULL || value->is_clear())
1707     return false;  // nothing to write => write nothing
1708   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1709   assert(loc != NULL, "");
1710   return loc->update_from(value);
1711 }
1712 
1713 
1714 //------------------------------TypeNode---------------------------------------
1715 // Node with a Type constant.
1716 class TypeNode : public Node {
1717 protected:
1718   virtual uint hash() const;    // Check the type
1719   virtual bool cmp( const Node &n ) const;
1720   virtual uint size_of() const; // Size is bigger
1721   const Type* const _type;
1722 public:
1723   void set_type(const Type* t) {
1724     assert(t != NULL, "sanity");
1725     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1726     *(const Type**)&_type = t;   // cast away const-ness
1727     // If this node is in the hash table, make sure it doesn't need a rehash.
1728     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1729   }
1730   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
1731   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1732     init_class_id(Class_Type);
1733   }
1734   virtual const Type* Value(PhaseGVN* phase) const;
1735   virtual const Type *bottom_type() const;
1736   virtual       uint  ideal_reg() const;
1737 #ifndef PRODUCT
1738   virtual void dump_spec(outputStream *st) const;
1739   virtual void dump_compact_spec(outputStream *st) const;
1740 #endif
1741 };
1742 
1743 #endif // SHARE_OPTO_NODE_HPP