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_MEMNODE_HPP
  26 #define SHARE_OPTO_MEMNODE_HPP
  27 
  28 #include "opto/multnode.hpp"
  29 #include "opto/node.hpp"
  30 #include "opto/opcodes.hpp"
  31 #include "opto/type.hpp"
  32 
  33 // Portions of code courtesy of Clifford Click
  34 
  35 class MultiNode;
  36 class PhaseCCP;
  37 class PhaseTransform;
  38 
  39 //------------------------------MemNode----------------------------------------
  40 // Load or Store, possibly throwing a NULL pointer exception
  41 class MemNode : public Node {
  42 private:
  43   bool _unaligned_access; // Unaligned access from unsafe
  44   bool _mismatched_access; // Mismatched access from unsafe: byte read in integer array for instance
  45   bool _unsafe_access;     // Access of unsafe origin.
  46 protected:
  47 #ifdef ASSERT
  48   const TypePtr* _adr_type;     // What kind of memory is being addressed?
  49 #endif
  50   virtual uint size_of() const;
  51 public:
  52   enum { Control,               // When is it safe to do this load?
  53          Memory,                // Chunk of memory is being loaded from
  54          Address,               // Actually address, derived from base
  55          ValueIn,               // Value to store
  56          OopStore               // Preceeding oop store, only in StoreCM
  57   };
  58   typedef enum { unordered = 0,
  59                  acquire,       // Load has to acquire or be succeeded by MemBarAcquire.
  60                  release,       // Store has to release or be preceded by MemBarRelease.
  61                  seqcst,        // LoadStore has to have both acquire and release semantics.
  62                  unset          // The memory ordering is not set (used for testing)
  63   } MemOrd;
  64 protected:
  65   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at )
  66     : Node(c0,c1,c2   ), _unaligned_access(false), _mismatched_access(false), _unsafe_access(false) {
  67     init_class_id(Class_Mem);
  68     debug_only(_adr_type=at; adr_type();)
  69   }
  70   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 )
  71     : Node(c0,c1,c2,c3), _unaligned_access(false), _mismatched_access(false), _unsafe_access(false) {
  72     init_class_id(Class_Mem);
  73     debug_only(_adr_type=at; adr_type();)
  74   }
  75   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4)
  76     : Node(c0,c1,c2,c3,c4), _unaligned_access(false), _mismatched_access(false), _unsafe_access(false) {
  77     init_class_id(Class_Mem);
  78     debug_only(_adr_type=at; adr_type();)
  79   }
  80 
  81   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { return NULL; }
  82   static bool check_if_adr_maybe_raw(Node* adr);
  83 
  84 public:
  85   // Helpers for the optimizer.  Documented in memnode.cpp.
  86   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
  87                                       Node* p2, AllocateNode* a2,
  88                                       PhaseTransform* phase);
  89   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
  90 
  91   static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
  92   static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
  93   // This one should probably be a phase-specific function:
  94   static bool all_controls_dominate(Node* dom, Node* sub);
  95 
  96   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
  97 
  98   // Shared code for Ideal methods:
  99   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.
 100 
 101   // Helper function for adr_type() implementations.
 102   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);
 103 
 104   // Raw access function, to allow copying of adr_type efficiently in
 105   // product builds and retain the debug info for debug builds.
 106   const TypePtr *raw_adr_type() const {
 107 #ifdef ASSERT
 108     return _adr_type;
 109 #else
 110     return 0;
 111 #endif
 112   }
 113 
 114   // Map a load or store opcode to its corresponding store opcode.
 115   // (Return -1 if unknown.)
 116   virtual int store_Opcode() const { return -1; }
 117 
 118   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 119   virtual BasicType memory_type() const = 0;
 120   virtual int memory_size() const {
 121 #ifdef ASSERT
 122     return type2aelembytes(memory_type(), true);
 123 #else
 124     return type2aelembytes(memory_type());
 125 #endif
 126   }
 127 
 128   // Search through memory states which precede this node (load or store).
 129   // Look for an exact match for the address, with no intervening
 130   // aliased stores.
 131   Node* find_previous_store(PhaseTransform* phase);
 132 
 133   // Can this node (load or store) accurately see a stored value in
 134   // the given memory state?  (The state may or may not be in(Memory).)
 135   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;
 136 
 137   void set_unaligned_access() { _unaligned_access = true; }
 138   bool is_unaligned_access() const { return _unaligned_access; }
 139   void set_mismatched_access() { _mismatched_access = true; }
 140   bool is_mismatched_access() const { return _mismatched_access; }
 141   void set_unsafe_access() { _unsafe_access = true; }
 142   bool is_unsafe_access() const { return _unsafe_access; }
 143 
 144 #ifndef PRODUCT
 145   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 146   virtual void dump_spec(outputStream *st) const;
 147 #endif
 148 };
 149 
 150 //------------------------------LoadNode---------------------------------------
 151 // Load value; requires Memory and Address
 152 class LoadNode : public MemNode {
 153 public:
 154   // Some loads (from unsafe) should be pinned: they don't depend only
 155   // on the dominating test.  The field _control_dependency below records
 156   // whether that node depends only on the dominating test.
 157   // Methods used to build LoadNodes pass an argument of type enum
 158   // ControlDependency instead of a boolean because those methods
 159   // typically have multiple boolean parameters with default values:
 160   // passing the wrong boolean to one of these parameters by mistake
 161   // goes easily unnoticed. Using an enum, the compiler can check that
 162   // the type of a value and the type of the parameter match.
 163   enum ControlDependency {
 164     Pinned,
 165     DependsOnlyOnTest
 166   };
 167 
 168 private:
 169   // LoadNode::hash() doesn't take the _control_dependency field
 170   // into account: If the graph already has a non-pinned LoadNode and
 171   // we add a pinned LoadNode with the same inputs, it's safe for GVN
 172   // to replace the pinned LoadNode with the non-pinned LoadNode,
 173   // otherwise it wouldn't be safe to have a non pinned LoadNode with
 174   // those inputs in the first place. If the graph already has a
 175   // pinned LoadNode and we add a non pinned LoadNode with the same
 176   // inputs, it's safe (but suboptimal) for GVN to replace the
 177   // non-pinned LoadNode by the pinned LoadNode.
 178   ControlDependency _control_dependency;
 179 
 180   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 181   // loads that can be reordered, and such requiring acquire semantics to
 182   // adhere to the Java specification.  The required behaviour is stored in
 183   // this field.
 184   const MemOrd _mo;
 185 
 186   uint _barrier; // Bit field with barrier information
 187 
 188 protected:
 189   virtual bool cmp(const Node &n) const;
 190   virtual uint size_of() const; // Size is bigger
 191   // Should LoadNode::Ideal() attempt to remove control edges?
 192   virtual bool can_remove_control() const;
 193   const Type* const _type;      // What kind of value is loaded?
 194 
 195   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const;
 196 public:
 197 
 198   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo, ControlDependency control_dependency)
 199     : MemNode(c,mem,adr,at), _control_dependency(control_dependency), _mo(mo), _barrier(0), _type(rt) {
 200     init_class_id(Class_Load);
 201   }
 202   inline bool is_unordered() const { return !is_acquire(); }
 203   inline bool is_acquire() const {
 204     assert(_mo == unordered || _mo == acquire, "unexpected");
 205     return _mo == acquire;
 206   }
 207   inline bool is_unsigned() const {
 208     int lop = Opcode();
 209     return (lop == Op_LoadUB) || (lop == Op_LoadUS);
 210   }
 211 
 212   // Polymorphic factory method:
 213   static Node* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 214                     const TypePtr* at, const Type *rt, BasicType bt,
 215                     MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 216                     bool unaligned = false, bool mismatched = false, bool unsafe = false);
 217 
 218   virtual uint hash()   const;  // Check the type
 219 
 220   // Handle algebraic identities here.  If we have an identity, return the Node
 221   // we are equivalent to.  We look for Load of a Store.
 222   virtual Node* Identity(PhaseGVN* phase);
 223 
 224   // If the load is from Field memory and the pointer is non-null, it might be possible to
 225   // zero out the control input.
 226   // If the offset is constant and the base is an object allocation,
 227   // try to hook me up to the exact initializing store.
 228   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 229 
 230   // Split instance field load through Phi.
 231   Node* split_through_phi(PhaseGVN *phase);
 232 
 233   // Recover original value from boxed values
 234   Node *eliminate_autobox(PhaseGVN *phase);
 235 
 236   // Compute a new Type for this node.  Basically we just do the pre-check,
 237   // then call the virtual add() to set the type.
 238   virtual const Type* Value(PhaseGVN* phase) const;
 239 
 240   // Common methods for LoadKlass and LoadNKlass nodes.
 241   const Type* klass_value_common(PhaseGVN* phase) const;
 242   Node* klass_identity_common(PhaseGVN* phase);
 243 
 244   virtual uint ideal_reg() const;
 245   virtual const Type *bottom_type() const;
 246   // Following method is copied from TypeNode:
 247   void set_type(const Type* t) {
 248     assert(t != NULL, "sanity");
 249     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 250     *(const Type**)&_type = t;   // cast away const-ness
 251     // If this node is in the hash table, make sure it doesn't need a rehash.
 252     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 253   }
 254   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
 255 
 256   // Do not match memory edge
 257   virtual uint match_edge(uint idx) const;
 258 
 259   // Map a load opcode to its corresponding store opcode.
 260   virtual int store_Opcode() const = 0;
 261 
 262   // Check if the load's memory input is a Phi node with the same control.
 263   bool is_instance_field_load_with_local_phi(Node* ctrl);
 264 
 265   Node* convert_to_unsigned_load(PhaseGVN& gvn);
 266   Node* convert_to_signed_load(PhaseGVN& gvn);
 267 
 268   void copy_barrier_info(const Node* src) { _barrier = src->as_Load()->_barrier; }
 269   uint barrier_data() { return _barrier; }
 270   void set_barrier_data(uint barrier_data) { _barrier |= barrier_data; }
 271 
 272 #ifndef PRODUCT
 273   virtual void dump_spec(outputStream *st) const;
 274 #endif
 275 #ifdef ASSERT
 276   // Helper function to allow a raw load without control edge for some cases
 277   static bool is_immutable_value(Node* adr);
 278 #endif
 279 protected:
 280   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 281                                      ciKlass* klass) const;
 282 
 283   Node* can_see_arraycopy_value(Node* st, PhaseGVN* phase) const;
 284 
 285   // depends_only_on_test is almost always true, and needs to be almost always
 286   // true to enable key hoisting & commoning optimizations.  However, for the
 287   // special case of RawPtr loads from TLS top & end, and other loads performed by
 288   // GC barriers, the control edge carries the dependence preventing hoisting past
 289   // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
 290   // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
 291   // which produce results (new raw memory state) inside of loops preventing all
 292   // manner of other optimizations).  Basically, it's ugly but so is the alternative.
 293   // See comment in macro.cpp, around line 125 expand_allocate_common().
 294   virtual bool depends_only_on_test() const {
 295     return adr_type() != TypeRawPtr::BOTTOM && _control_dependency == DependsOnlyOnTest;
 296   }
 297 };
 298 
 299 //------------------------------LoadBNode--------------------------------------
 300 // Load a byte (8bits signed) from memory
 301 class LoadBNode : public LoadNode {
 302 public:
 303   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 304     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 305   virtual int Opcode() const;
 306   virtual uint ideal_reg() const { return Op_RegI; }
 307   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 308   virtual const Type* Value(PhaseGVN* phase) const;
 309   virtual int store_Opcode() const { return Op_StoreB; }
 310   virtual BasicType memory_type() const { return T_BYTE; }
 311 };
 312 
 313 //------------------------------LoadUBNode-------------------------------------
 314 // Load a unsigned byte (8bits unsigned) from memory
 315 class LoadUBNode : public LoadNode {
 316 public:
 317   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 318     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 319   virtual int Opcode() const;
 320   virtual uint ideal_reg() const { return Op_RegI; }
 321   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 322   virtual const Type* Value(PhaseGVN* phase) const;
 323   virtual int store_Opcode() const { return Op_StoreB; }
 324   virtual BasicType memory_type() const { return T_BYTE; }
 325 };
 326 
 327 //------------------------------LoadUSNode-------------------------------------
 328 // Load an unsigned short/char (16bits unsigned) from memory
 329 class LoadUSNode : public LoadNode {
 330 public:
 331   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 332     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 333   virtual int Opcode() const;
 334   virtual uint ideal_reg() const { return Op_RegI; }
 335   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 336   virtual const Type* Value(PhaseGVN* phase) const;
 337   virtual int store_Opcode() const { return Op_StoreC; }
 338   virtual BasicType memory_type() const { return T_CHAR; }
 339 };
 340 
 341 //------------------------------LoadSNode--------------------------------------
 342 // Load a short (16bits signed) from memory
 343 class LoadSNode : public LoadNode {
 344 public:
 345   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 346     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 347   virtual int Opcode() const;
 348   virtual uint ideal_reg() const { return Op_RegI; }
 349   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 350   virtual const Type* Value(PhaseGVN* phase) const;
 351   virtual int store_Opcode() const { return Op_StoreC; }
 352   virtual BasicType memory_type() const { return T_SHORT; }
 353 };
 354 
 355 //------------------------------LoadINode--------------------------------------
 356 // Load an integer from memory
 357 class LoadINode : public LoadNode {
 358 public:
 359   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 360     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 361   virtual int Opcode() const;
 362   virtual uint ideal_reg() const { return Op_RegI; }
 363   virtual int store_Opcode() const { return Op_StoreI; }
 364   virtual BasicType memory_type() const { return T_INT; }
 365 };
 366 
 367 //------------------------------LoadRangeNode----------------------------------
 368 // Load an array length from the array
 369 class LoadRangeNode : public LoadINode {
 370 public:
 371   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 372     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
 373   virtual int Opcode() const;
 374   virtual const Type* Value(PhaseGVN* phase) const;
 375   virtual Node* Identity(PhaseGVN* phase);
 376   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 377 };
 378 
 379 //------------------------------LoadLNode--------------------------------------
 380 // Load a long from memory
 381 class LoadLNode : public LoadNode {
 382   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 383   virtual bool cmp( const Node &n ) const {
 384     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 385       && LoadNode::cmp(n);
 386   }
 387   virtual uint size_of() const { return sizeof(*this); }
 388   const bool _require_atomic_access;  // is piecewise load forbidden?
 389 
 390 public:
 391   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 392             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 393     : LoadNode(c, mem, adr, at, tl, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 394   virtual int Opcode() const;
 395   virtual uint ideal_reg() const { return Op_RegL; }
 396   virtual int store_Opcode() const { return Op_StoreL; }
 397   virtual BasicType memory_type() const { return T_LONG; }
 398   bool require_atomic_access() const { return _require_atomic_access; }
 399   static LoadLNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 400                                 const Type* rt, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 401                                 bool unaligned = false, bool mismatched = false, bool unsafe = false);
 402 #ifndef PRODUCT
 403   virtual void dump_spec(outputStream *st) const {
 404     LoadNode::dump_spec(st);
 405     if (_require_atomic_access)  st->print(" Atomic!");
 406   }
 407 #endif
 408 };
 409 
 410 //------------------------------LoadL_unalignedNode----------------------------
 411 // Load a long from unaligned memory
 412 class LoadL_unalignedNode : public LoadLNode {
 413 public:
 414   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 415     : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo, control_dependency) {}
 416   virtual int Opcode() const;
 417 };
 418 
 419 //------------------------------LoadFNode--------------------------------------
 420 // Load a float (64 bits) from memory
 421 class LoadFNode : public LoadNode {
 422 public:
 423   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 424     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 425   virtual int Opcode() const;
 426   virtual uint ideal_reg() const { return Op_RegF; }
 427   virtual int store_Opcode() const { return Op_StoreF; }
 428   virtual BasicType memory_type() const { return T_FLOAT; }
 429 };
 430 
 431 //------------------------------LoadDNode--------------------------------------
 432 // Load a double (64 bits) from memory
 433 class LoadDNode : public LoadNode {
 434   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 435   virtual bool cmp( const Node &n ) const {
 436     return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
 437       && LoadNode::cmp(n);
 438   }
 439   virtual uint size_of() const { return sizeof(*this); }
 440   const bool _require_atomic_access;  // is piecewise load forbidden?
 441 
 442 public:
 443   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
 444             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 445     : LoadNode(c, mem, adr, at, t, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 446   virtual int Opcode() const;
 447   virtual uint ideal_reg() const { return Op_RegD; }
 448   virtual int store_Opcode() const { return Op_StoreD; }
 449   virtual BasicType memory_type() const { return T_DOUBLE; }
 450   bool require_atomic_access() const { return _require_atomic_access; }
 451   static LoadDNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 452                                 const Type* rt, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 453                                 bool unaligned = false, bool mismatched = false, bool unsafe = false);
 454 #ifndef PRODUCT
 455   virtual void dump_spec(outputStream *st) const {
 456     LoadNode::dump_spec(st);
 457     if (_require_atomic_access)  st->print(" Atomic!");
 458   }
 459 #endif
 460 };
 461 
 462 //------------------------------LoadD_unalignedNode----------------------------
 463 // Load a double from unaligned memory
 464 class LoadD_unalignedNode : public LoadDNode {
 465 public:
 466   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 467     : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo, control_dependency) {}
 468   virtual int Opcode() const;
 469 };
 470 
 471 //------------------------------LoadPNode--------------------------------------
 472 // Load a pointer from memory (either object or array)
 473 class LoadPNode : public LoadNode {
 474 public:
 475   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 476     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 477   virtual int Opcode() const;
 478   virtual uint ideal_reg() const { return Op_RegP; }
 479   virtual int store_Opcode() const { return Op_StoreP; }
 480   virtual BasicType memory_type() const { return T_ADDRESS; }
 481 };
 482 
 483 
 484 //------------------------------LoadNNode--------------------------------------
 485 // Load a narrow oop from memory (either object or array)
 486 class LoadNNode : public LoadNode {
 487 public:
 488   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 489     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 490   virtual int Opcode() const;
 491   virtual uint ideal_reg() const { return Op_RegN; }
 492   virtual int store_Opcode() const { return Op_StoreN; }
 493   virtual BasicType memory_type() const { return T_NARROWOOP; }
 494 };
 495 
 496 //------------------------------LoadKlassNode----------------------------------
 497 // Load a Klass from an object
 498 class LoadKlassNode : public LoadPNode {
 499 protected:
 500   // In most cases, LoadKlassNode does not have the control input set. If the control
 501   // input is set, it must not be removed (by LoadNode::Ideal()).
 502   virtual bool can_remove_control() const;
 503 public:
 504   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
 505     : LoadPNode(c, mem, adr, at, tk, mo) {}
 506   virtual int Opcode() const;
 507   virtual const Type* Value(PhaseGVN* phase) const;
 508   virtual Node* Identity(PhaseGVN* phase);
 509   virtual bool depends_only_on_test() const { return true; }
 510 
 511   // Polymorphic factory method:
 512   static Node* make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at,
 513                     const TypeKlassPtr* tk = TypeKlassPtr::OBJECT);
 514 };
 515 
 516 //------------------------------LoadNKlassNode---------------------------------
 517 // Load a narrow Klass from an object.
 518 class LoadNKlassNode : public LoadNNode {
 519 public:
 520   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, MemOrd mo)
 521     : LoadNNode(c, mem, adr, at, tk, mo) {}
 522   virtual int Opcode() const;
 523   virtual uint ideal_reg() const { return Op_RegN; }
 524   virtual int store_Opcode() const { return Op_StoreNKlass; }
 525   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 526 
 527   virtual const Type* Value(PhaseGVN* phase) const;
 528   virtual Node* Identity(PhaseGVN* phase);
 529   virtual bool depends_only_on_test() const { return true; }
 530 };
 531 
 532 
 533 //------------------------------StoreNode--------------------------------------
 534 // Store value; requires Store, Address and Value
 535 class StoreNode : public MemNode {
 536 private:
 537   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 538   // stores that can be reordered, and such requiring release semantics to
 539   // adhere to the Java specification.  The required behaviour is stored in
 540   // this field.
 541   const MemOrd _mo;
 542   // Needed for proper cloning.
 543   virtual uint size_of() const { return sizeof(*this); }
 544 protected:
 545   virtual bool cmp( const Node &n ) const;
 546   virtual bool depends_only_on_test() const { return false; }
 547 
 548   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 549   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 550 
 551 public:
 552   // We must ensure that stores of object references will be visible
 553   // only after the object's initialization. So the callers of this
 554   // procedure must indicate that the store requires `release'
 555   // semantics, if the stored value is an object reference that might
 556   // point to a new object and may become externally visible.
 557   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 558     : MemNode(c, mem, adr, at, val), _mo(mo) {
 559     init_class_id(Class_Store);
 560   }
 561   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 562     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 563     init_class_id(Class_Store);
 564   }
 565 
 566   inline bool is_unordered() const { return !is_release(); }
 567   inline bool is_release() const {
 568     assert((_mo == unordered || _mo == release), "unexpected");
 569     return _mo == release;
 570   }
 571 
 572   // Conservatively release stores of object references in order to
 573   // ensure visibility of object initialization.
 574   static inline MemOrd release_if_reference(const BasicType t) {
 575 #ifdef AARCH64
 576     // AArch64 doesn't need a release store here because object
 577     // initialization contains the necessary barriers.
 578     return unordered;
 579 #else
 580     const MemOrd mo = (t == T_ARRAY ||
 581                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 582                        t == T_OBJECT) ? release : unordered;
 583     return mo;
 584 #endif
 585   }
 586 
 587   // Polymorphic factory method
 588   //
 589   // We must ensure that stores of object references will be visible
 590   // only after the object's initialization. So the callers of this
 591   // procedure must indicate that the store requires `release'
 592   // semantics, if the stored value is an object reference that might
 593   // point to a new object and may become externally visible.
 594   static StoreNode* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 595                          const TypePtr* at, Node *val, BasicType bt, MemOrd mo);
 596 
 597   virtual uint hash() const;    // Check the type
 598 
 599   // If the store is to Field memory and the pointer is non-null, we can
 600   // zero out the control input.
 601   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 602 
 603   // Compute a new Type for this node.  Basically we just do the pre-check,
 604   // then call the virtual add() to set the type.
 605   virtual const Type* Value(PhaseGVN* phase) const;
 606 
 607   // Check for identity function on memory (Load then Store at same address)
 608   virtual Node* Identity(PhaseGVN* phase);
 609 
 610   // Do not match memory edge
 611   virtual uint match_edge(uint idx) const;
 612 
 613   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 614 
 615   // Map a store opcode to its corresponding own opcode, trivially.
 616   virtual int store_Opcode() const { return Opcode(); }
 617 
 618   // have all possible loads of the value stored been optimized away?
 619   bool value_never_loaded(PhaseTransform *phase) const;
 620 
 621   MemBarNode* trailing_membar() const;
 622 };
 623 
 624 //------------------------------StoreBNode-------------------------------------
 625 // Store byte to memory
 626 class StoreBNode : public StoreNode {
 627 public:
 628   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 629     : StoreNode(c, mem, adr, at, val, mo) {}
 630   virtual int Opcode() const;
 631   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 632   virtual BasicType memory_type() const { return T_BYTE; }
 633 };
 634 
 635 //------------------------------StoreCNode-------------------------------------
 636 // Store char/short to memory
 637 class StoreCNode : public StoreNode {
 638 public:
 639   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 640     : StoreNode(c, mem, adr, at, val, mo) {}
 641   virtual int Opcode() const;
 642   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 643   virtual BasicType memory_type() const { return T_CHAR; }
 644 };
 645 
 646 //------------------------------StoreINode-------------------------------------
 647 // Store int to memory
 648 class StoreINode : public StoreNode {
 649 public:
 650   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 651     : StoreNode(c, mem, adr, at, val, mo) {}
 652   virtual int Opcode() const;
 653   virtual BasicType memory_type() const { return T_INT; }
 654 };
 655 
 656 //------------------------------StoreLNode-------------------------------------
 657 // Store long to memory
 658 class StoreLNode : public StoreNode {
 659   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 660   virtual bool cmp( const Node &n ) const {
 661     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 662       && StoreNode::cmp(n);
 663   }
 664   virtual uint size_of() const { return sizeof(*this); }
 665   const bool _require_atomic_access;  // is piecewise store forbidden?
 666 
 667 public:
 668   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 669     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 670   virtual int Opcode() const;
 671   virtual BasicType memory_type() const { return T_LONG; }
 672   bool require_atomic_access() const { return _require_atomic_access; }
 673   static StoreLNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 674 #ifndef PRODUCT
 675   virtual void dump_spec(outputStream *st) const {
 676     StoreNode::dump_spec(st);
 677     if (_require_atomic_access)  st->print(" Atomic!");
 678   }
 679 #endif
 680 };
 681 
 682 //------------------------------StoreFNode-------------------------------------
 683 // Store float to memory
 684 class StoreFNode : public StoreNode {
 685 public:
 686   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 687     : StoreNode(c, mem, adr, at, val, mo) {}
 688   virtual int Opcode() const;
 689   virtual BasicType memory_type() const { return T_FLOAT; }
 690 };
 691 
 692 //------------------------------StoreDNode-------------------------------------
 693 // Store double to memory
 694 class StoreDNode : public StoreNode {
 695   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 696   virtual bool cmp( const Node &n ) const {
 697     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 698       && StoreNode::cmp(n);
 699   }
 700   virtual uint size_of() const { return sizeof(*this); }
 701   const bool _require_atomic_access;  // is piecewise store forbidden?
 702 public:
 703   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 704              MemOrd mo, bool require_atomic_access = false)
 705     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 706   virtual int Opcode() const;
 707   virtual BasicType memory_type() const { return T_DOUBLE; }
 708   bool require_atomic_access() const { return _require_atomic_access; }
 709   static StoreDNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 710 #ifndef PRODUCT
 711   virtual void dump_spec(outputStream *st) const {
 712     StoreNode::dump_spec(st);
 713     if (_require_atomic_access)  st->print(" Atomic!");
 714   }
 715 #endif
 716 
 717 };
 718 
 719 //------------------------------StorePNode-------------------------------------
 720 // Store pointer to memory
 721 class StorePNode : public StoreNode {
 722 public:
 723   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 724     : StoreNode(c, mem, adr, at, val, mo) {}
 725   virtual int Opcode() const;
 726   virtual BasicType memory_type() const { return T_ADDRESS; }
 727 };
 728 
 729 //------------------------------StoreNNode-------------------------------------
 730 // Store narrow oop to memory
 731 class StoreNNode : public StoreNode {
 732 public:
 733   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 734     : StoreNode(c, mem, adr, at, val, mo) {}
 735   virtual int Opcode() const;
 736   virtual BasicType memory_type() const { return T_NARROWOOP; }
 737 };
 738 
 739 //------------------------------StoreNKlassNode--------------------------------------
 740 // Store narrow klass to memory
 741 class StoreNKlassNode : public StoreNNode {
 742 public:
 743   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 744     : StoreNNode(c, mem, adr, at, val, mo) {}
 745   virtual int Opcode() const;
 746   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 747 };
 748 
 749 //------------------------------StoreCMNode-----------------------------------
 750 // Store card-mark byte to memory for CM
 751 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store
 752 // Preceeding equivalent StoreCMs may be eliminated.
 753 class StoreCMNode : public StoreNode {
 754  private:
 755   virtual uint hash() const { return StoreNode::hash() + _oop_alias_idx; }
 756   virtual bool cmp( const Node &n ) const {
 757     return _oop_alias_idx == ((StoreCMNode&)n)._oop_alias_idx
 758       && StoreNode::cmp(n);
 759   }
 760   virtual uint size_of() const { return sizeof(*this); }
 761   int _oop_alias_idx;   // The alias_idx of OopStore
 762 
 763 public:
 764   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, int oop_alias_idx ) :
 765     StoreNode(c, mem, adr, at, val, oop_store, MemNode::release),
 766     _oop_alias_idx(oop_alias_idx) {
 767     assert(_oop_alias_idx >= Compile::AliasIdxRaw ||
 768            _oop_alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
 769            "bad oop alias idx");
 770   }
 771   virtual int Opcode() const;
 772   virtual Node* Identity(PhaseGVN* phase);
 773   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 774   virtual const Type* Value(PhaseGVN* phase) const;
 775   virtual BasicType memory_type() const { return T_VOID; } // unspecific
 776   int oop_alias_idx() const { return _oop_alias_idx; }
 777 };
 778 
 779 //------------------------------LoadPLockedNode---------------------------------
 780 // Load-locked a pointer from memory (either object or array).
 781 // On Sparc & Intel this is implemented as a normal pointer load.
 782 // On PowerPC and friends it's a real load-locked.
 783 class LoadPLockedNode : public LoadPNode {
 784 public:
 785   LoadPLockedNode(Node *c, Node *mem, Node *adr, MemOrd mo)
 786     : LoadPNode(c, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM, mo) {}
 787   virtual int Opcode() const;
 788   virtual int store_Opcode() const { return Op_StorePConditional; }
 789   virtual bool depends_only_on_test() const { return true; }
 790 };
 791 
 792 //------------------------------SCMemProjNode---------------------------------------
 793 // This class defines a projection of the memory  state of a store conditional node.
 794 // These nodes return a value, but also update memory.
 795 class SCMemProjNode : public ProjNode {
 796 public:
 797   enum {SCMEMPROJCON = (uint)-2};
 798   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 799   virtual int Opcode() const;
 800   virtual bool      is_CFG() const  { return false; }
 801   virtual const Type *bottom_type() const {return Type::MEMORY;}
 802   virtual const TypePtr *adr_type() const {
 803     Node* ctrl = in(0);
 804     if (ctrl == NULL)  return NULL; // node is dead
 805     return ctrl->in(MemNode::Memory)->adr_type();
 806   }
 807   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 808   virtual const Type* Value(PhaseGVN* phase) const;
 809 #ifndef PRODUCT
 810   virtual void dump_spec(outputStream *st) const {};
 811 #endif
 812 };
 813 
 814 //------------------------------LoadStoreNode---------------------------
 815 // Note: is_Mem() method returns 'true' for this class.
 816 class LoadStoreNode : public Node {
 817 private:
 818   const Type* const _type;      // What kind of value is loaded?
 819   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 820   bool _has_barrier;
 821   virtual uint size_of() const; // Size is bigger
 822 public:
 823   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 824   virtual bool depends_only_on_test() const { return false; }
 825   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 826 
 827   virtual const Type *bottom_type() const { return _type; }
 828   virtual uint ideal_reg() const;
 829   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 830 
 831   bool result_not_used() const;
 832   MemBarNode* trailing_membar() const;
 833   void set_has_barrier() { _has_barrier = true; };
 834   bool has_barrier() const { return _has_barrier; };
 835 };
 836 
 837 class LoadStoreConditionalNode : public LoadStoreNode {
 838 public:
 839   enum {
 840     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 841   };
 842   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 843 };
 844 
 845 //------------------------------StorePConditionalNode---------------------------
 846 // Conditionally store pointer to memory, if no change since prior
 847 // load-locked.  Sets flags for success or failure of the store.
 848 class StorePConditionalNode : public LoadStoreConditionalNode {
 849 public:
 850   StorePConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 851   virtual int Opcode() const;
 852   // Produces flags
 853   virtual uint ideal_reg() const { return Op_RegFlags; }
 854 };
 855 
 856 //------------------------------StoreIConditionalNode---------------------------
 857 // Conditionally store int to memory, if no change since prior
 858 // load-locked.  Sets flags for success or failure of the store.
 859 class StoreIConditionalNode : public LoadStoreConditionalNode {
 860 public:
 861   StoreIConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ii ) : LoadStoreConditionalNode(c, mem, adr, val, ii) { }
 862   virtual int Opcode() const;
 863   // Produces flags
 864   virtual uint ideal_reg() const { return Op_RegFlags; }
 865 };
 866 
 867 //------------------------------StoreLConditionalNode---------------------------
 868 // Conditionally store long to memory, if no change since prior
 869 // load-locked.  Sets flags for success or failure of the store.
 870 class StoreLConditionalNode : public LoadStoreConditionalNode {
 871 public:
 872   StoreLConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 873   virtual int Opcode() const;
 874   // Produces flags
 875   virtual uint ideal_reg() const { return Op_RegFlags; }
 876 };
 877 
 878 class CompareAndSwapNode : public LoadStoreConditionalNode {
 879 private:
 880   const MemNode::MemOrd _mem_ord;
 881 public:
 882   CompareAndSwapNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : LoadStoreConditionalNode(c, mem, adr, val, ex), _mem_ord(mem_ord) {}
 883   MemNode::MemOrd order() const {
 884     return _mem_ord;
 885   }
 886 };
 887 
 888 class CompareAndExchangeNode : public LoadStoreNode {
 889 private:
 890   const MemNode::MemOrd _mem_ord;
 891 public:
 892   enum {
 893     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 894   };
 895   CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
 896     LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
 897      init_req(ExpectedIn, ex );
 898   }
 899 
 900   MemNode::MemOrd order() const {
 901     return _mem_ord;
 902   }
 903 };
 904 
 905 //------------------------------CompareAndSwapBNode---------------------------
 906 class CompareAndSwapBNode : public CompareAndSwapNode {
 907 public:
 908   CompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 909   virtual int Opcode() const;
 910 };
 911 
 912 //------------------------------CompareAndSwapSNode---------------------------
 913 class CompareAndSwapSNode : public CompareAndSwapNode {
 914 public:
 915   CompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 916   virtual int Opcode() const;
 917 };
 918 
 919 //------------------------------CompareAndSwapINode---------------------------
 920 class CompareAndSwapINode : public CompareAndSwapNode {
 921 public:
 922   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 923   virtual int Opcode() const;
 924 };
 925 
 926 //------------------------------CompareAndSwapLNode---------------------------
 927 class CompareAndSwapLNode : public CompareAndSwapNode {
 928 public:
 929   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 930   virtual int Opcode() const;
 931 };
 932 
 933 //------------------------------CompareAndSwapPNode---------------------------
 934 class CompareAndSwapPNode : public CompareAndSwapNode {
 935 public:
 936   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 937   virtual int Opcode() const;
 938 };
 939 
 940 //------------------------------CompareAndSwapNNode---------------------------
 941 class CompareAndSwapNNode : public CompareAndSwapNode {
 942 public:
 943   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 944   virtual int Opcode() const;
 945 };
 946 
 947 //------------------------------WeakCompareAndSwapBNode---------------------------
 948 class WeakCompareAndSwapBNode : public CompareAndSwapNode {
 949 public:
 950   WeakCompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 951   virtual int Opcode() const;
 952 };
 953 
 954 //------------------------------WeakCompareAndSwapSNode---------------------------
 955 class WeakCompareAndSwapSNode : public CompareAndSwapNode {
 956 public:
 957   WeakCompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 958   virtual int Opcode() const;
 959 };
 960 
 961 //------------------------------WeakCompareAndSwapINode---------------------------
 962 class WeakCompareAndSwapINode : public CompareAndSwapNode {
 963 public:
 964   WeakCompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 965   virtual int Opcode() const;
 966 };
 967 
 968 //------------------------------WeakCompareAndSwapLNode---------------------------
 969 class WeakCompareAndSwapLNode : public CompareAndSwapNode {
 970 public:
 971   WeakCompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 972   virtual int Opcode() const;
 973 };
 974 
 975 //------------------------------WeakCompareAndSwapPNode---------------------------
 976 class WeakCompareAndSwapPNode : public CompareAndSwapNode {
 977 public:
 978   WeakCompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 979   virtual int Opcode() const;
 980 };
 981 
 982 //------------------------------WeakCompareAndSwapNNode---------------------------
 983 class WeakCompareAndSwapNNode : public CompareAndSwapNode {
 984 public:
 985   WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 986   virtual int Opcode() const;
 987 };
 988 
 989 //------------------------------CompareAndExchangeBNode---------------------------
 990 class CompareAndExchangeBNode : public CompareAndExchangeNode {
 991 public:
 992   CompareAndExchangeBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::BYTE) { }
 993   virtual int Opcode() const;
 994 };
 995 
 996 
 997 //------------------------------CompareAndExchangeSNode---------------------------
 998 class CompareAndExchangeSNode : public CompareAndExchangeNode {
 999 public:
1000   CompareAndExchangeSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::SHORT) { }
1001   virtual int Opcode() const;
1002 };
1003 
1004 //------------------------------CompareAndExchangeLNode---------------------------
1005 class CompareAndExchangeLNode : public CompareAndExchangeNode {
1006 public:
1007   CompareAndExchangeLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeLong::LONG) { }
1008   virtual int Opcode() const;
1009 };
1010 
1011 
1012 //------------------------------CompareAndExchangeINode---------------------------
1013 class CompareAndExchangeINode : public CompareAndExchangeNode {
1014 public:
1015   CompareAndExchangeINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::INT) { }
1016   virtual int Opcode() const;
1017 };
1018 
1019 
1020 //------------------------------CompareAndExchangePNode---------------------------
1021 class CompareAndExchangePNode : public CompareAndExchangeNode {
1022 public:
1023   CompareAndExchangePNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
1024   virtual int Opcode() const;
1025 };
1026 
1027 //------------------------------CompareAndExchangeNNode---------------------------
1028 class CompareAndExchangeNNode : public CompareAndExchangeNode {
1029 public:
1030   CompareAndExchangeNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
1031   virtual int Opcode() const;
1032 };
1033 
1034 //------------------------------GetAndAddBNode---------------------------
1035 class GetAndAddBNode : public LoadStoreNode {
1036 public:
1037   GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1038   virtual int Opcode() const;
1039 };
1040 
1041 //------------------------------GetAndAddSNode---------------------------
1042 class GetAndAddSNode : public LoadStoreNode {
1043 public:
1044   GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1045   virtual int Opcode() const;
1046 };
1047 
1048 //------------------------------GetAndAddINode---------------------------
1049 class GetAndAddINode : public LoadStoreNode {
1050 public:
1051   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1052   virtual int Opcode() const;
1053 };
1054 
1055 //------------------------------GetAndAddLNode---------------------------
1056 class GetAndAddLNode : public LoadStoreNode {
1057 public:
1058   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1059   virtual int Opcode() const;
1060 };
1061 
1062 //------------------------------GetAndSetBNode---------------------------
1063 class GetAndSetBNode : public LoadStoreNode {
1064 public:
1065   GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1066   virtual int Opcode() const;
1067 };
1068 
1069 //------------------------------GetAndSetSNode---------------------------
1070 class GetAndSetSNode : public LoadStoreNode {
1071 public:
1072   GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1073   virtual int Opcode() const;
1074 };
1075 
1076 //------------------------------GetAndSetINode---------------------------
1077 class GetAndSetINode : public LoadStoreNode {
1078 public:
1079   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1080   virtual int Opcode() const;
1081 };
1082 
1083 //------------------------------GetAndSetLNode---------------------------
1084 class GetAndSetLNode : public LoadStoreNode {
1085 public:
1086   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1087   virtual int Opcode() const;
1088 };
1089 
1090 //------------------------------GetAndSetPNode---------------------------
1091 class GetAndSetPNode : public LoadStoreNode {
1092 public:
1093   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1094   virtual int Opcode() const;
1095 };
1096 
1097 //------------------------------GetAndSetNNode---------------------------
1098 class GetAndSetNNode : public LoadStoreNode {
1099 public:
1100   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1101   virtual int Opcode() const;
1102 };
1103 
1104 //------------------------------ClearArray-------------------------------------
1105 class ClearArrayNode: public Node {
1106 private:
1107   bool _is_large;
1108 public:
1109   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, bool is_large)
1110     : Node(ctrl,arymem,word_cnt,base), _is_large(is_large) {
1111     init_class_id(Class_ClearArray);
1112   }
1113   virtual int         Opcode() const;
1114   virtual const Type *bottom_type() const { return Type::MEMORY; }
1115   // ClearArray modifies array elements, and so affects only the
1116   // array memory addressed by the bottom_type of its base address.
1117   virtual const class TypePtr *adr_type() const;
1118   virtual Node* Identity(PhaseGVN* phase);
1119   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1120   virtual uint match_edge(uint idx) const;
1121   bool is_large() const { return _is_large; }
1122 
1123   // Clear the given area of an object or array.
1124   // The start offset must always be aligned mod BytesPerInt.
1125   // The end offset must always be aligned mod BytesPerLong.
1126   // Return the new memory.
1127   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1128                             intptr_t start_offset,
1129                             intptr_t end_offset,
1130                             PhaseGVN* phase);
1131   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1132                             intptr_t start_offset,
1133                             Node* end_offset,
1134                             PhaseGVN* phase);
1135   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1136                             Node* start_offset,
1137                             Node* end_offset,
1138                             PhaseGVN* phase);
1139   // Return allocation input memory edge if it is different instance
1140   // or itself if it is the one we are looking for.
1141   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
1142 };
1143 
1144 //------------------------------MemBar-----------------------------------------
1145 // There are different flavors of Memory Barriers to match the Java Memory
1146 // Model.  Monitor-enter and volatile-load act as Aquires: no following ref
1147 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
1148 // volatile-load.  Monitor-exit and volatile-store act as Release: no
1149 // preceding ref can be moved to after them.  We insert a MemBar-Release
1150 // before a FastUnlock or volatile-store.  All volatiles need to be
1151 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
1152 // separate it from any following volatile-load.
1153 class MemBarNode: public MultiNode {
1154   virtual uint hash() const ;                  // { return NO_HASH; }
1155   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1156 
1157   virtual uint size_of() const { return sizeof(*this); }
1158   // Memory type this node is serializing.  Usually either rawptr or bottom.
1159   const TypePtr* _adr_type;
1160 
1161   // How is this membar related to a nearby memory access?
1162   enum {
1163     Standalone,
1164     TrailingLoad,
1165     TrailingStore,
1166     LeadingStore,
1167     TrailingLoadStore,
1168     LeadingLoadStore
1169   } _kind;
1170 
1171 #ifdef ASSERT
1172   uint _pair_idx;
1173 #endif
1174 
1175 public:
1176   enum {
1177     Precedent = TypeFunc::Parms  // optional edge to force precedence
1178   };
1179   MemBarNode(Compile* C, int alias_idx, Node* precedent);
1180   virtual int Opcode() const = 0;
1181   virtual const class TypePtr *adr_type() const { return _adr_type; }
1182   virtual const Type* Value(PhaseGVN* phase) const;
1183   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1184   virtual uint match_edge(uint idx) const { return 0; }
1185   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
1186   virtual Node *match( const ProjNode *proj, const Matcher *m );
1187   // Factory method.  Builds a wide or narrow membar.
1188   // Optional 'precedent' becomes an extra edge if not null.
1189   static MemBarNode* make(Compile* C, int opcode,
1190                           int alias_idx = Compile::AliasIdxBot,
1191                           Node* precedent = NULL);
1192 
1193   MemBarNode* trailing_membar() const;
1194   MemBarNode* leading_membar() const;
1195 
1196   void set_trailing_load() { _kind = TrailingLoad; }
1197   bool trailing_load() const { return _kind == TrailingLoad; }
1198   bool trailing_store() const { return _kind == TrailingStore; }
1199   bool leading_store() const { return _kind == LeadingStore; }
1200   bool trailing_load_store() const { return _kind == TrailingLoadStore; }
1201   bool leading_load_store() const { return _kind == LeadingLoadStore; }
1202   bool trailing() const { return _kind == TrailingLoad || _kind == TrailingStore || _kind == TrailingLoadStore; }
1203   bool leading() const { return _kind == LeadingStore || _kind == LeadingLoadStore; }
1204   bool standalone() const { return _kind == Standalone; }
1205 
1206   static void set_store_pair(MemBarNode* leading, MemBarNode* trailing);
1207   static void set_load_store_pair(MemBarNode* leading, MemBarNode* trailing);
1208 
1209   void remove(PhaseIterGVN *igvn);
1210 };
1211 
1212 // "Acquire" - no following ref can move before (but earlier refs can
1213 // follow, like an early Load stalled in cache).  Requires multi-cpu
1214 // visibility.  Inserted after a volatile load.
1215 class MemBarAcquireNode: public MemBarNode {
1216 public:
1217   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1218     : MemBarNode(C, alias_idx, precedent) {}
1219   virtual int Opcode() const;
1220 };
1221 
1222 // "Acquire" - no following ref can move before (but earlier refs can
1223 // follow, like an early Load stalled in cache).  Requires multi-cpu
1224 // visibility.  Inserted independ of any load, as required
1225 // for intrinsic Unsafe.loadFence().
1226 class LoadFenceNode: public MemBarNode {
1227 public:
1228   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
1229     : MemBarNode(C, alias_idx, precedent) {}
1230   virtual int Opcode() const;
1231 };
1232 
1233 // "Release" - no earlier ref can move after (but later refs can move
1234 // up, like a speculative pipelined cache-hitting Load).  Requires
1235 // multi-cpu visibility.  Inserted before a volatile store.
1236 class MemBarReleaseNode: public MemBarNode {
1237 public:
1238   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1239     : MemBarNode(C, alias_idx, precedent) {}
1240   virtual int Opcode() const;
1241 };
1242 
1243 // "Release" - no earlier ref can move after (but later refs can move
1244 // up, like a speculative pipelined cache-hitting Load).  Requires
1245 // multi-cpu visibility.  Inserted independent of any store, as required
1246 // for intrinsic Unsafe.storeFence().
1247 class StoreFenceNode: public MemBarNode {
1248 public:
1249   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1250     : MemBarNode(C, alias_idx, precedent) {}
1251   virtual int Opcode() const;
1252 };
1253 
1254 // "Acquire" - no following ref can move before (but earlier refs can
1255 // follow, like an early Load stalled in cache).  Requires multi-cpu
1256 // visibility.  Inserted after a FastLock.
1257 class MemBarAcquireLockNode: public MemBarNode {
1258 public:
1259   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1260     : MemBarNode(C, alias_idx, precedent) {}
1261   virtual int Opcode() const;
1262 };
1263 
1264 // "Release" - no earlier ref can move after (but later refs can move
1265 // up, like a speculative pipelined cache-hitting Load).  Requires
1266 // multi-cpu visibility.  Inserted before a FastUnLock.
1267 class MemBarReleaseLockNode: public MemBarNode {
1268 public:
1269   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1270     : MemBarNode(C, alias_idx, precedent) {}
1271   virtual int Opcode() const;
1272 };
1273 
1274 class MemBarStoreStoreNode: public MemBarNode {
1275 public:
1276   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1277     : MemBarNode(C, alias_idx, precedent) {
1278     init_class_id(Class_MemBarStoreStore);
1279   }
1280   virtual int Opcode() const;
1281 };
1282 
1283 // Ordering between a volatile store and a following volatile load.
1284 // Requires multi-CPU visibility?
1285 class MemBarVolatileNode: public MemBarNode {
1286 public:
1287   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1288     : MemBarNode(C, alias_idx, precedent) {}
1289   virtual int Opcode() const;
1290 };
1291 
1292 // Ordering within the same CPU.  Used to order unsafe memory references
1293 // inside the compiler when we lack alias info.  Not needed "outside" the
1294 // compiler because the CPU does all the ordering for us.
1295 class MemBarCPUOrderNode: public MemBarNode {
1296 public:
1297   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1298     : MemBarNode(C, alias_idx, precedent) {}
1299   virtual int Opcode() const;
1300   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1301 };
1302 
1303 class OnSpinWaitNode: public MemBarNode {
1304 public:
1305   OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
1306     : MemBarNode(C, alias_idx, precedent) {}
1307   virtual int Opcode() const;
1308 };
1309 
1310 // Isolation of object setup after an AllocateNode and before next safepoint.
1311 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1312 class InitializeNode: public MemBarNode {
1313   friend class AllocateNode;
1314 
1315   enum {
1316     Incomplete    = 0,
1317     Complete      = 1,
1318     WithArraycopy = 2
1319   };
1320   int _is_complete;
1321 
1322   bool _does_not_escape;
1323 
1324 public:
1325   enum {
1326     Control    = TypeFunc::Control,
1327     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1328     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1329     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1330   };
1331 
1332   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1333   virtual int Opcode() const;
1334   virtual uint size_of() const { return sizeof(*this); }
1335   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1336   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1337 
1338   // Manage incoming memory edges via a MergeMem on in(Memory):
1339   Node* memory(uint alias_idx);
1340 
1341   // The raw memory edge coming directly from the Allocation.
1342   // The contents of this memory are *always* all-zero-bits.
1343   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1344 
1345   // Return the corresponding allocation for this initialization (or null if none).
1346   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1347   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1348   AllocateNode* allocation();
1349 
1350   // Anything other than zeroing in this init?
1351   bool is_non_zero();
1352 
1353   // An InitializeNode must completed before macro expansion is done.
1354   // Completion requires that the AllocateNode must be followed by
1355   // initialization of the new memory to zero, then to any initializers.
1356   bool is_complete() { return _is_complete != Incomplete; }
1357   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1358 
1359   // Mark complete.  (Must not yet be complete.)
1360   void set_complete(PhaseGVN* phase);
1361   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1362 
1363   bool does_not_escape() { return _does_not_escape; }
1364   void set_does_not_escape() { _does_not_escape = true; }
1365 
1366 #ifdef ASSERT
1367   // ensure all non-degenerate stores are ordered and non-overlapping
1368   bool stores_are_sane(PhaseTransform* phase);
1369 #endif //ASSERT
1370 
1371   // See if this store can be captured; return offset where it initializes.
1372   // Return 0 if the store cannot be moved (any sort of problem).
1373   intptr_t can_capture_store(StoreNode* st, PhaseTransform* phase, bool can_reshape);
1374 
1375   // Capture another store; reformat it to write my internal raw memory.
1376   // Return the captured copy, else NULL if there is some sort of problem.
1377   Node* capture_store(StoreNode* st, intptr_t start, PhaseTransform* phase, bool can_reshape);
1378 
1379   // Find captured store which corresponds to the range [start..start+size).
1380   // Return my own memory projection (meaning the initial zero bits)
1381   // if there is no such store.  Return NULL if there is a problem.
1382   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);
1383 
1384   // Called when the associated AllocateNode is expanded into CFG.
1385   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1386                         intptr_t header_size, Node* size_in_bytes,
1387                         PhaseGVN* phase);
1388 
1389  private:
1390   void remove_extra_zeroes();
1391 
1392   // Find out where a captured store should be placed (or already is placed).
1393   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1394                                      PhaseTransform* phase);
1395 
1396   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);
1397 
1398   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);
1399 
1400   bool detect_init_independence(Node* n, int& count);
1401 
1402   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1403                                PhaseGVN* phase);
1404 
1405   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1406 };
1407 
1408 //------------------------------MergeMem---------------------------------------
1409 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1410 class MergeMemNode: public Node {
1411   virtual uint hash() const ;                  // { return NO_HASH; }
1412   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1413   friend class MergeMemStream;
1414   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1415 
1416 public:
1417   // If the input is a whole memory state, clone it with all its slices intact.
1418   // Otherwise, make a new memory state with just that base memory input.
1419   // In either case, the result is a newly created MergeMem.
1420   static MergeMemNode* make(Node* base_memory);
1421 
1422   virtual int Opcode() const;
1423   virtual Node* Identity(PhaseGVN* phase);
1424   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1425   virtual uint ideal_reg() const { return NotAMachineReg; }
1426   virtual uint match_edge(uint idx) const { return 0; }
1427   virtual const RegMask &out_RegMask() const;
1428   virtual const Type *bottom_type() const { return Type::MEMORY; }
1429   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1430   // sparse accessors
1431   // Fetch the previously stored "set_memory_at", or else the base memory.
1432   // (Caller should clone it if it is a phi-nest.)
1433   Node* memory_at(uint alias_idx) const;
1434   // set the memory, regardless of its previous value
1435   void set_memory_at(uint alias_idx, Node* n);
1436   // the "base" is the memory that provides the non-finite support
1437   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1438   // warning: setting the base can implicitly set any of the other slices too
1439   void set_base_memory(Node* def);
1440   // sentinel value which denotes a copy of the base memory:
1441   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1442   static Node* make_empty_memory(); // where the sentinel comes from
1443   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1444   // hook for the iterator, to perform any necessary setup
1445   void iteration_setup(const MergeMemNode* other = NULL);
1446   // push sentinels until I am at least as long as the other (semantic no-op)
1447   void grow_to_match(const MergeMemNode* other);
1448   bool verify_sparse() const PRODUCT_RETURN0;
1449 #ifndef PRODUCT
1450   virtual void dump_spec(outputStream *st) const;
1451 #endif
1452 };
1453 
1454 class MergeMemStream : public StackObj {
1455  private:
1456   MergeMemNode*       _mm;
1457   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1458   Node*               _mm_base;  // loop-invariant base memory of _mm
1459   int                 _idx;
1460   int                 _cnt;
1461   Node*               _mem;
1462   Node*               _mem2;
1463   int                 _cnt2;
1464 
1465   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {
1466     // subsume_node will break sparseness at times, whenever a memory slice
1467     // folds down to a copy of the base ("fat") memory.  In such a case,
1468     // the raw edge will update to base, although it should be top.
1469     // This iterator will recognize either top or base_memory as an
1470     // "empty" slice.  See is_empty, is_empty2, and next below.
1471     //
1472     // The sparseness property is repaired in MergeMemNode::Ideal.
1473     // As long as access to a MergeMem goes through this iterator
1474     // or the memory_at accessor, flaws in the sparseness will
1475     // never be observed.
1476     //
1477     // Also, iteration_setup repairs sparseness.
1478     assert(mm->verify_sparse(), "please, no dups of base");
1479     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");
1480 
1481     _mm  = mm;
1482     _mm_base = mm->base_memory();
1483     _mm2 = mm2;
1484     _cnt = mm->req();
1485     _idx = Compile::AliasIdxBot-1; // start at the base memory
1486     _mem = NULL;
1487     _mem2 = NULL;
1488   }
1489 
1490 #ifdef ASSERT
1491   Node* check_memory() const {
1492     if (at_base_memory())
1493       return _mm->base_memory();
1494     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1495       return _mm->memory_at(_idx);
1496     else
1497       return _mm_base;
1498   }
1499   Node* check_memory2() const {
1500     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1501   }
1502 #endif
1503 
1504   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1505   void assert_synch() const {
1506     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1507            "no side-effects except through the stream");
1508   }
1509 
1510  public:
1511 
1512   // expected usages:
1513   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1514   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1515 
1516   // iterate over one merge
1517   MergeMemStream(MergeMemNode* mm) {
1518     mm->iteration_setup();
1519     init(mm);
1520     debug_only(_cnt2 = 999);
1521   }
1522   // iterate in parallel over two merges
1523   // only iterates through non-empty elements of mm2
1524   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1525     assert(mm2, "second argument must be a MergeMem also");
1526     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1527     mm->iteration_setup(mm2);
1528     init(mm, mm2);
1529     _cnt2 = mm2->req();
1530   }
1531 #ifdef ASSERT
1532   ~MergeMemStream() {
1533     assert_synch();
1534   }
1535 #endif
1536 
1537   MergeMemNode* all_memory() const {
1538     return _mm;
1539   }
1540   Node* base_memory() const {
1541     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1542     return _mm_base;
1543   }
1544   const MergeMemNode* all_memory2() const {
1545     assert(_mm2 != NULL, "");
1546     return _mm2;
1547   }
1548   bool at_base_memory() const {
1549     return _idx == Compile::AliasIdxBot;
1550   }
1551   int alias_idx() const {
1552     assert(_mem, "must call next 1st");
1553     return _idx;
1554   }
1555 
1556   const TypePtr* adr_type() const {
1557     return Compile::current()->get_adr_type(alias_idx());
1558   }
1559 
1560   const TypePtr* adr_type(Compile* C) const {
1561     return C->get_adr_type(alias_idx());
1562   }
1563   bool is_empty() const {
1564     assert(_mem, "must call next 1st");
1565     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1566     return _mem->is_top();
1567   }
1568   bool is_empty2() const {
1569     assert(_mem2, "must call next 1st");
1570     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1571     return _mem2->is_top();
1572   }
1573   Node* memory() const {
1574     assert(!is_empty(), "must not be empty");
1575     assert_synch();
1576     return _mem;
1577   }
1578   // get the current memory, regardless of empty or non-empty status
1579   Node* force_memory() const {
1580     assert(!is_empty() || !at_base_memory(), "");
1581     // Use _mm_base to defend against updates to _mem->base_memory().
1582     Node *mem = _mem->is_top() ? _mm_base : _mem;
1583     assert(mem == check_memory(), "");
1584     return mem;
1585   }
1586   Node* memory2() const {
1587     assert(_mem2 == check_memory2(), "");
1588     return _mem2;
1589   }
1590   void set_memory(Node* mem) {
1591     if (at_base_memory()) {
1592       // Note that this does not change the invariant _mm_base.
1593       _mm->set_base_memory(mem);
1594     } else {
1595       _mm->set_memory_at(_idx, mem);
1596     }
1597     _mem = mem;
1598     assert_synch();
1599   }
1600 
1601   // Recover from a side effect to the MergeMemNode.
1602   void set_memory() {
1603     _mem = _mm->in(_idx);
1604   }
1605 
1606   bool next()  { return next(false); }
1607   bool next2() { return next(true); }
1608 
1609   bool next_non_empty()  { return next_non_empty(false); }
1610   bool next_non_empty2() { return next_non_empty(true); }
1611   // next_non_empty2 can yield states where is_empty() is true
1612 
1613  private:
1614   // find the next item, which might be empty
1615   bool next(bool have_mm2) {
1616     assert((_mm2 != NULL) == have_mm2, "use other next");
1617     assert_synch();
1618     if (++_idx < _cnt) {
1619       // Note:  This iterator allows _mm to be non-sparse.
1620       // It behaves the same whether _mem is top or base_memory.
1621       _mem = _mm->in(_idx);
1622       if (have_mm2)
1623         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1624       return true;
1625     }
1626     return false;
1627   }
1628 
1629   // find the next non-empty item
1630   bool next_non_empty(bool have_mm2) {
1631     while (next(have_mm2)) {
1632       if (!is_empty()) {
1633         // make sure _mem2 is filled in sensibly
1634         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1635         return true;
1636       } else if (have_mm2 && !is_empty2()) {
1637         return true;   // is_empty() == true
1638       }
1639     }
1640     return false;
1641   }
1642 };
1643 
1644 //------------------------------Prefetch---------------------------------------
1645 
1646 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1647 class PrefetchAllocationNode : public Node {
1648 public:
1649   PrefetchAllocationNode(Node *mem, Node *adr) : Node(0,mem,adr) {}
1650   virtual int Opcode() const;
1651   virtual uint ideal_reg() const { return NotAMachineReg; }
1652   virtual uint match_edge(uint idx) const { return idx==2; }
1653   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1654 };
1655 
1656 #endif // SHARE_OPTO_MEMNODE_HPP