1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_MEMNODE_HPP
  26 #define SHARE_VM_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 protected:
  46 #ifdef ASSERT
  47   const TypePtr* _adr_type;     // What kind of memory is being addressed?
  48 #endif
  49   virtual uint size_of() const;
  50 public:
  51   enum { Control,               // When is it safe to do this load?
  52          Memory,                // Chunk of memory is being loaded from
  53          Address,               // Actually address, derived from base
  54          ValueIn,               // Value to store
  55          OopStore               // Preceeding oop store, only in StoreCM
  56   };
  57   typedef enum { unordered = 0,
  58                  acquire,       // Load has to acquire or be succeeded by MemBarAcquire.
  59                  release,       // Store has to release or be preceded by MemBarRelease.
  60                  seqcst,        // LoadStore has to have both acquire and release semantics.
  61                  unset          // The memory ordering is not set (used for testing)
  62   } MemOrd;
  63 protected:
  64   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at )
  65     : Node(c0,c1,c2   ), _unaligned_access(false), _mismatched_access(false) {
  66     init_class_id(Class_Mem);
  67     debug_only(_adr_type=at; adr_type();)
  68   }
  69   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 )
  70     : Node(c0,c1,c2,c3), _unaligned_access(false), _mismatched_access(false) {
  71     init_class_id(Class_Mem);
  72     debug_only(_adr_type=at; adr_type();)
  73   }
  74   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4)
  75     : Node(c0,c1,c2,c3,c4), _unaligned_access(false), _mismatched_access(false) {
  76     init_class_id(Class_Mem);
  77     debug_only(_adr_type=at; adr_type();)
  78   }
  79 
  80   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { return NULL; }
  81 
  82 public:
  83   // Helpers for the optimizer.  Documented in memnode.cpp.
  84   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
  85                                       Node* p2, AllocateNode* a2,
  86                                       PhaseTransform* phase);
  87   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
  88 
  89   static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
  90   static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
  91   // This one should probably be a phase-specific function:
  92   static bool all_controls_dominate(Node* dom, Node* sub);
  93 
  94   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
  95 
  96   // Shared code for Ideal methods:
  97   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.
  98 
  99   // Helper function for adr_type() implementations.
 100   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);
 101 
 102   // Raw access function, to allow copying of adr_type efficiently in
 103   // product builds and retain the debug info for debug builds.
 104   const TypePtr *raw_adr_type() const {
 105 #ifdef ASSERT
 106     return _adr_type;
 107 #else
 108     return 0;
 109 #endif
 110   }
 111 
 112   // Map a load or store opcode to its corresponding store opcode.
 113   // (Return -1 if unknown.)
 114   virtual Opcodes store_Opcode() const { return Opcodes::MaxVal; }
 115 
 116   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 117   virtual BasicType memory_type() const = 0;
 118   virtual int memory_size() const {
 119 #ifdef ASSERT
 120     return type2aelembytes(memory_type(), true);
 121 #else
 122     return type2aelembytes(memory_type());
 123 #endif
 124   }
 125 
 126   // Search through memory states which precede this node (load or store).
 127   // Look for an exact match for the address, with no intervening
 128   // aliased stores.
 129   Node* find_previous_store(PhaseTransform* phase);
 130 
 131   // Can this node (load or store) accurately see a stored value in
 132   // the given memory state?  (The state may or may not be in(Memory).)
 133   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;
 134 
 135   void set_unaligned_access() { _unaligned_access = true; }
 136   bool is_unaligned_access() const { return _unaligned_access; }
 137   void set_mismatched_access() { _mismatched_access = true; }
 138   bool is_mismatched_access() const { return _mismatched_access; }
 139 
 140 #ifndef PRODUCT
 141   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 142   virtual void dump_spec(outputStream *st) const;
 143 #endif
 144 };
 145 
 146 //------------------------------LoadNode---------------------------------------
 147 // Load value; requires Memory and Address
 148 class LoadNode : public MemNode {
 149 public:
 150   // Some loads (from unsafe) should be pinned: they don't depend only
 151   // on the dominating test.  The field _control_dependency below records
 152   // whether that node depends only on the dominating test.
 153   // Methods used to build LoadNodes pass an argument of type enum
 154   // ControlDependency instead of a boolean because those methods
 155   // typically have multiple boolean parameters with default values:
 156   // passing the wrong boolean to one of these parameters by mistake
 157   // goes easily unnoticed. Using an enum, the compiler can check that
 158   // the type of a value and the type of the parameter match.
 159   enum ControlDependency {
 160     Pinned,
 161     DependsOnlyOnTest
 162   };
 163 private:
 164   // LoadNode::hash() doesn't take the _control_dependency field
 165   // into account: If the graph already has a non-pinned LoadNode and
 166   // we add a pinned LoadNode with the same inputs, it's safe for GVN
 167   // to replace the pinned LoadNode with the non-pinned LoadNode,
 168   // otherwise it wouldn't be safe to have a non pinned LoadNode with
 169   // those inputs in the first place. If the graph already has a
 170   // pinned LoadNode and we add a non pinned LoadNode with the same
 171   // inputs, it's safe (but suboptimal) for GVN to replace the
 172   // non-pinned LoadNode by the pinned LoadNode.
 173   ControlDependency _control_dependency;
 174 
 175   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 176   // loads that can be reordered, and such requiring acquire semantics to
 177   // adhere to the Java specification.  The required behaviour is stored in
 178   // this field.
 179   const MemOrd _mo;
 180 
 181 protected:
 182   virtual uint cmp(const Node &n) const;
 183   virtual uint size_of() const; // Size is bigger
 184   // Should LoadNode::Ideal() attempt to remove control edges?
 185   virtual bool can_remove_control() const;
 186   const Type* const _type;      // What kind of value is loaded?
 187 
 188   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const;
 189 public:
 190 
 191   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo, ControlDependency control_dependency)
 192     : MemNode(c,mem,adr,at), _type(rt), _mo(mo), _control_dependency(control_dependency) {
 193     init_class_id(Class_Load);
 194   }
 195   inline bool is_unordered() const { return !is_acquire(); }
 196   inline bool is_acquire() const {
 197     assert(_mo == unordered || _mo == acquire, "unexpected");
 198     return _mo == acquire;
 199   }
 200   inline bool is_unsigned() const {
 201     Opcodes lop = Opcode();
 202     return (lop == Opcodes::Op_LoadUB) || (lop == Opcodes::Op_LoadUS);
 203   }
 204 
 205   // Polymorphic factory method:
 206   static Node* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 207                     const TypePtr* at, const Type *rt, BasicType bt,
 208                     MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 209                     bool unaligned = false, bool mismatched = false);
 210 
 211   virtual uint hash()   const;  // Check the type
 212 
 213   // Handle algebraic identities here.  If we have an identity, return the Node
 214   // we are equivalent to.  We look for Load of a Store.
 215   virtual Node* Identity(PhaseGVN* phase);
 216 
 217   // If the load is from Field memory and the pointer is non-null, it might be possible to
 218   // zero out the control input.
 219   // If the offset is constant and the base is an object allocation,
 220   // try to hook me up to the exact initializing store.
 221   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 222 
 223   // Split instance field load through Phi.
 224   Node* split_through_phi(PhaseGVN *phase);
 225 
 226   // Recover original value from boxed values
 227   Node *eliminate_autobox(PhaseGVN *phase);
 228 
 229   // Compute a new Type for this node.  Basically we just do the pre-check,
 230   // then call the virtual add() to set the type.
 231   virtual const Type* Value(PhaseGVN* phase) const;
 232 
 233   // Common methods for LoadKlass and LoadNKlass nodes.
 234   const Type* klass_value_common(PhaseGVN* phase) const;
 235   Node* klass_identity_common(PhaseGVN* phase);
 236 
 237   virtual Opcodes ideal_reg() const;
 238   virtual const Type *bottom_type() const;
 239   // Following method is copied from TypeNode:
 240   void set_type(const Type* t) {
 241     assert(t != NULL, "sanity");
 242     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 243     *(const Type**)&_type = t;   // cast away const-ness
 244     // If this node is in the hash table, make sure it doesn't need a rehash.
 245     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 246   }
 247   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
 248 
 249   // Do not match memory edge
 250   virtual uint match_edge(uint idx) const;
 251 
 252   // Map a load opcode to its corresponding store opcode.
 253   virtual Opcodes store_Opcode() const = 0;
 254 
 255   // Check if the load's memory input is a Phi node with the same control.
 256   bool is_instance_field_load_with_local_phi(Node* ctrl);
 257 
 258   Node* convert_to_unsigned_load(PhaseGVN& gvn);
 259   Node* convert_to_signed_load(PhaseGVN& gvn);
 260 
 261 #ifndef PRODUCT
 262   virtual void dump_spec(outputStream *st) const;
 263 #endif
 264 #ifdef ASSERT
 265   // Helper function to allow a raw load without control edge for some cases
 266   static bool is_immutable_value(Node* adr);
 267 #endif
 268 protected:
 269   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 270                                      ciKlass* klass) const;
 271 
 272   Node* can_see_arraycopy_value(Node* st, PhaseTransform* phase) const;
 273 
 274   // depends_only_on_test is almost always true, and needs to be almost always
 275   // true to enable key hoisting & commoning optimizations.  However, for the
 276   // special case of RawPtr loads from TLS top & end, and other loads performed by
 277   // GC barriers, the control edge carries the dependence preventing hoisting past
 278   // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
 279   // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
 280   // which produce results (new raw memory state) inside of loops preventing all
 281   // manner of other optimizations).  Basically, it's ugly but so is the alternative.
 282   // See comment in macro.cpp, around line 125 expand_allocate_common().
 283   virtual bool depends_only_on_test() const {
 284     return adr_type() != TypeRawPtr::BOTTOM && _control_dependency == DependsOnlyOnTest;
 285   }
 286 };
 287 
 288 //------------------------------LoadBNode--------------------------------------
 289 // Load a byte (8bits signed) from memory
 290 class LoadBNode : public LoadNode {
 291 public:
 292   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 293     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 294   virtual Opcodes Opcode() const;
 295   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegI; }
 296   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 297   virtual const Type* Value(PhaseGVN* phase) const;
 298   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreB; }
 299   virtual BasicType memory_type() const { return T_BYTE; }
 300 };
 301 
 302 //------------------------------LoadUBNode-------------------------------------
 303 // Load a unsigned byte (8bits unsigned) from memory
 304 class LoadUBNode : public LoadNode {
 305 public:
 306   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 307     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 308   virtual Opcodes Opcode() const;
 309   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegI; }
 310   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 311   virtual const Type* Value(PhaseGVN* phase) const;
 312   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreB; }
 313   virtual BasicType memory_type() const { return T_BYTE; }
 314 };
 315 
 316 //------------------------------LoadUSNode-------------------------------------
 317 // Load an unsigned short/char (16bits unsigned) from memory
 318 class LoadUSNode : public LoadNode {
 319 public:
 320   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 321     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 322   virtual Opcodes Opcode() const;
 323   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegI; }
 324   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 325   virtual const Type* Value(PhaseGVN* phase) const;
 326   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreC; }
 327   virtual BasicType memory_type() const { return T_CHAR; }
 328 };
 329 
 330 //------------------------------LoadSNode--------------------------------------
 331 // Load a short (16bits signed) from memory
 332 class LoadSNode : public LoadNode {
 333 public:
 334   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 335     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 336   virtual Opcodes Opcode() const;
 337   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegI; }
 338   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 339   virtual const Type* Value(PhaseGVN* phase) const;
 340   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreC; }
 341   virtual BasicType memory_type() const { return T_SHORT; }
 342 };
 343 
 344 //------------------------------LoadINode--------------------------------------
 345 // Load an integer from memory
 346 class LoadINode : public LoadNode {
 347 public:
 348   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 349     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 350   virtual Opcodes Opcode() const;
 351   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegI; }
 352   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreI; }
 353   virtual BasicType memory_type() const { return T_INT; }
 354 };
 355 
 356 //------------------------------LoadRangeNode----------------------------------
 357 // Load an array length from the array
 358 class LoadRangeNode : public LoadINode {
 359 public:
 360   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 361     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
 362   virtual Opcodes Opcode() const;
 363   virtual const Type* Value(PhaseGVN* phase) const;
 364   virtual Node* Identity(PhaseGVN* phase);
 365   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 366 };
 367 
 368 //------------------------------LoadLNode--------------------------------------
 369 // Load a long from memory
 370 class LoadLNode : public LoadNode {
 371   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 372   virtual uint cmp( const Node &n ) const {
 373     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 374       && LoadNode::cmp(n);
 375   }
 376   virtual uint size_of() const { return sizeof(*this); }
 377   const bool _require_atomic_access;  // is piecewise load forbidden?
 378 
 379 public:
 380   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 381             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 382     : LoadNode(c, mem, adr, at, tl, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 383   virtual Opcodes Opcode() const;
 384   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegL; }
 385   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreL; }
 386   virtual BasicType memory_type() const { return T_LONG; }
 387   bool require_atomic_access() const { return _require_atomic_access; }
 388   static LoadLNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 389                                 const Type* rt, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 390                                 bool unaligned = false, bool mismatched = false);
 391 #ifndef PRODUCT
 392   virtual void dump_spec(outputStream *st) const {
 393     LoadNode::dump_spec(st);
 394     if (_require_atomic_access)  st->print(" Atomic!");
 395   }
 396 #endif
 397 };
 398 
 399 //------------------------------LoadL_unalignedNode----------------------------
 400 // Load a long from unaligned memory
 401 class LoadL_unalignedNode : public LoadLNode {
 402 public:
 403   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 404     : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo, control_dependency) {}
 405   virtual Opcodes Opcode() const;
 406 };
 407 
 408 //------------------------------LoadFNode--------------------------------------
 409 // Load a float (64 bits) from memory
 410 class LoadFNode : public LoadNode {
 411 public:
 412   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 413     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 414   virtual Opcodes Opcode() const;
 415   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegF; }
 416   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreF; }
 417   virtual BasicType memory_type() const { return T_FLOAT; }
 418 };
 419 
 420 //------------------------------LoadDNode--------------------------------------
 421 // Load a double (64 bits) from memory
 422 class LoadDNode : public LoadNode {
 423   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 424   virtual uint cmp( const Node &n ) const {
 425     return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
 426       && LoadNode::cmp(n);
 427   }
 428   virtual uint size_of() const { return sizeof(*this); }
 429   const bool _require_atomic_access;  // is piecewise load forbidden?
 430 
 431 public:
 432   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
 433             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 434     : LoadNode(c, mem, adr, at, t, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 435   virtual Opcodes Opcode() const;
 436   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegD; }
 437   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreD; }
 438   virtual BasicType memory_type() const { return T_DOUBLE; }
 439   bool require_atomic_access() const { return _require_atomic_access; }
 440   static LoadDNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 441                                 const Type* rt, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 442                                 bool unaligned = false, bool mismatched = false);
 443 #ifndef PRODUCT
 444   virtual void dump_spec(outputStream *st) const {
 445     LoadNode::dump_spec(st);
 446     if (_require_atomic_access)  st->print(" Atomic!");
 447   }
 448 #endif
 449 };
 450 
 451 //------------------------------LoadD_unalignedNode----------------------------
 452 // Load a double from unaligned memory
 453 class LoadD_unalignedNode : public LoadDNode {
 454 public:
 455   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 456     : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo, control_dependency) {}
 457   virtual Opcodes Opcode() const;
 458 };
 459 
 460 //------------------------------LoadPNode--------------------------------------
 461 // Load a pointer from memory (either object or array)
 462 class LoadPNode : public LoadNode {
 463 public:
 464   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 465     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 466   virtual Opcodes Opcode() const;
 467   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegP; }
 468   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreP; }
 469   virtual BasicType memory_type() const { return T_ADDRESS; }
 470 };
 471 
 472 
 473 //------------------------------LoadNNode--------------------------------------
 474 // Load a narrow oop from memory (either object or array)
 475 class LoadNNode : public LoadNode {
 476 public:
 477   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 478     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 479   virtual Opcodes Opcode() const;
 480   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegN; }
 481   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreN; }
 482   virtual BasicType memory_type() const { return T_NARROWOOP; }
 483 };
 484 
 485 //------------------------------LoadKlassNode----------------------------------
 486 // Load a Klass from an object
 487 class LoadKlassNode : public LoadPNode {
 488 protected:
 489   // In most cases, LoadKlassNode does not have the control input set. If the control
 490   // input is set, it must not be removed (by LoadNode::Ideal()).
 491   virtual bool can_remove_control() const;
 492 public:
 493   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
 494     : LoadPNode(c, mem, adr, at, tk, mo) {}
 495   virtual Opcodes Opcode() const;
 496   virtual const Type* Value(PhaseGVN* phase) const;
 497   virtual Node* Identity(PhaseGVN* phase);
 498   virtual bool depends_only_on_test() const { return true; }
 499 
 500   // Polymorphic factory method:
 501   static Node* make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at,
 502                     const TypeKlassPtr* tk = TypeKlassPtr::OBJECT);
 503 };
 504 
 505 //------------------------------LoadNKlassNode---------------------------------
 506 // Load a narrow Klass from an object.
 507 class LoadNKlassNode : public LoadNNode {
 508 public:
 509   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, MemOrd mo)
 510     : LoadNNode(c, mem, adr, at, tk, mo) {}
 511   virtual Opcodes Opcode() const;
 512   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegN; }
 513   virtual Opcodes store_Opcode() const { return Opcodes::Op_StoreNKlass; }
 514   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 515 
 516   virtual const Type* Value(PhaseGVN* phase) const;
 517   virtual Node* Identity(PhaseGVN* phase);
 518   virtual bool depends_only_on_test() const { return true; }
 519 };
 520 
 521 
 522 //------------------------------StoreNode--------------------------------------
 523 // Store value; requires Store, Address and Value
 524 class StoreNode : public MemNode {
 525 private:
 526   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 527   // stores that can be reordered, and such requiring release semantics to
 528   // adhere to the Java specification.  The required behaviour is stored in
 529   // this field.
 530   const MemOrd _mo;
 531   // Needed for proper cloning.
 532   virtual uint size_of() const { return sizeof(*this); }
 533 protected:
 534   virtual uint cmp( const Node &n ) const;
 535   virtual bool depends_only_on_test() const { return false; }
 536 
 537   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 538   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 539 
 540 public:
 541   // We must ensure that stores of object references will be visible
 542   // only after the object's initialization. So the callers of this
 543   // procedure must indicate that the store requires `release'
 544   // semantics, if the stored value is an object reference that might
 545   // point to a new object and may become externally visible.
 546   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 547     : MemNode(c, mem, adr, at, val), _mo(mo) {
 548     init_class_id(Class_Store);
 549   }
 550   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 551     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 552     init_class_id(Class_Store);
 553   }
 554 
 555   inline bool is_unordered() const { return !is_release(); }
 556   inline bool is_release() const {
 557     assert((_mo == unordered || _mo == release), "unexpected");
 558     return _mo == release;
 559   }
 560 
 561   // Conservatively release stores of object references in order to
 562   // ensure visibility of object initialization.
 563   static inline MemOrd release_if_reference(const BasicType t) {
 564 #ifdef AARCH64
 565     // AArch64 doesn't need a release store here because object
 566     // initialization contains the necessary barriers.
 567     return unordered;
 568 #else
 569     const MemOrd mo = (t == T_ARRAY ||
 570                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 571                        t == T_OBJECT) ? release : unordered;
 572     return mo;
 573 #endif
 574   }
 575 
 576   // Polymorphic factory method
 577   //
 578   // We must ensure that stores of object references will be visible
 579   // only after the object's initialization. So the callers of this
 580   // procedure must indicate that the store requires `release'
 581   // semantics, if the stored value is an object reference that might
 582   // point to a new object and may become externally visible.
 583   static StoreNode* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 584                          const TypePtr* at, Node *val, BasicType bt, MemOrd mo);
 585 
 586   virtual uint hash() const;    // Check the type
 587 
 588   // If the store is to Field memory and the pointer is non-null, we can
 589   // zero out the control input.
 590   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 591 
 592   // Compute a new Type for this node.  Basically we just do the pre-check,
 593   // then call the virtual add() to set the type.
 594   virtual const Type* Value(PhaseGVN* phase) const;
 595 
 596   // Check for identity function on memory (Load then Store at same address)
 597   virtual Node* Identity(PhaseGVN* phase);
 598 
 599   // Do not match memory edge
 600   virtual uint match_edge(uint idx) const;
 601 
 602   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 603 
 604   // Map a store opcode to its corresponding own opcode, trivially.
 605   virtual Opcodes store_Opcode() const { return Opcode(); }
 606 
 607   // have all possible loads of the value stored been optimized away?
 608   bool value_never_loaded(PhaseTransform *phase) const;
 609 };
 610 
 611 //------------------------------StoreBNode-------------------------------------
 612 // Store byte to memory
 613 class StoreBNode : public StoreNode {
 614 public:
 615   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 616     : StoreNode(c, mem, adr, at, val, mo) {}
 617   virtual Opcodes Opcode() const;
 618   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 619   virtual BasicType memory_type() const { return T_BYTE; }
 620 };
 621 
 622 //------------------------------StoreCNode-------------------------------------
 623 // Store char/short to memory
 624 class StoreCNode : public StoreNode {
 625 public:
 626   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 627     : StoreNode(c, mem, adr, at, val, mo) {}
 628   virtual Opcodes Opcode() const;
 629   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 630   virtual BasicType memory_type() const { return T_CHAR; }
 631 };
 632 
 633 //------------------------------StoreINode-------------------------------------
 634 // Store int to memory
 635 class StoreINode : public StoreNode {
 636 public:
 637   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 638     : StoreNode(c, mem, adr, at, val, mo) {}
 639   virtual Opcodes Opcode() const;
 640   virtual BasicType memory_type() const { return T_INT; }
 641 };
 642 
 643 //------------------------------StoreLNode-------------------------------------
 644 // Store long to memory
 645 class StoreLNode : public StoreNode {
 646   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 647   virtual uint cmp( const Node &n ) const {
 648     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 649       && StoreNode::cmp(n);
 650   }
 651   virtual uint size_of() const { return sizeof(*this); }
 652   const bool _require_atomic_access;  // is piecewise store forbidden?
 653 
 654 public:
 655   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 656     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 657   virtual Opcodes Opcode() const;
 658   virtual BasicType memory_type() const { return T_LONG; }
 659   bool require_atomic_access() const { return _require_atomic_access; }
 660   static StoreLNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 661 #ifndef PRODUCT
 662   virtual void dump_spec(outputStream *st) const {
 663     StoreNode::dump_spec(st);
 664     if (_require_atomic_access)  st->print(" Atomic!");
 665   }
 666 #endif
 667 };
 668 
 669 //------------------------------StoreFNode-------------------------------------
 670 // Store float to memory
 671 class StoreFNode : public StoreNode {
 672 public:
 673   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 674     : StoreNode(c, mem, adr, at, val, mo) {}
 675   virtual Opcodes Opcode() const;
 676   virtual BasicType memory_type() const { return T_FLOAT; }
 677 };
 678 
 679 //------------------------------StoreDNode-------------------------------------
 680 // Store double to memory
 681 class StoreDNode : public StoreNode {
 682   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 683   virtual uint cmp( const Node &n ) const {
 684     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 685       && StoreNode::cmp(n);
 686   }
 687   virtual uint size_of() const { return sizeof(*this); }
 688   const bool _require_atomic_access;  // is piecewise store forbidden?
 689 public:
 690   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 691              MemOrd mo, bool require_atomic_access = false)
 692     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 693   virtual Opcodes Opcode() const;
 694   virtual BasicType memory_type() const { return T_DOUBLE; }
 695   bool require_atomic_access() const { return _require_atomic_access; }
 696   static StoreDNode* make_atomic(Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 697 #ifndef PRODUCT
 698   virtual void dump_spec(outputStream *st) const {
 699     StoreNode::dump_spec(st);
 700     if (_require_atomic_access)  st->print(" Atomic!");
 701   }
 702 #endif
 703 
 704 };
 705 
 706 //------------------------------StorePNode-------------------------------------
 707 // Store pointer to memory
 708 class StorePNode : public StoreNode {
 709 public:
 710   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 711     : StoreNode(c, mem, adr, at, val, mo) {}
 712   virtual Opcodes Opcode() const;
 713   virtual BasicType memory_type() const { return T_ADDRESS; }
 714 };
 715 
 716 //------------------------------StoreNNode-------------------------------------
 717 // Store narrow oop to memory
 718 class StoreNNode : public StoreNode {
 719 public:
 720   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 721     : StoreNode(c, mem, adr, at, val, mo) {}
 722   virtual Opcodes Opcode() const;
 723   virtual BasicType memory_type() const { return T_NARROWOOP; }
 724 };
 725 
 726 //------------------------------StoreNKlassNode--------------------------------------
 727 // Store narrow klass to memory
 728 class StoreNKlassNode : public StoreNNode {
 729 public:
 730   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 731     : StoreNNode(c, mem, adr, at, val, mo) {}
 732   virtual Opcodes Opcode() const;
 733   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 734 };
 735 
 736 //------------------------------StoreCMNode-----------------------------------
 737 // Store card-mark byte to memory for CM
 738 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store
 739 // Preceeding equivalent StoreCMs may be eliminated.
 740 class StoreCMNode : public StoreNode {
 741  private:
 742   virtual uint hash() const { return StoreNode::hash() + _oop_alias_idx; }
 743   virtual uint cmp( const Node &n ) const {
 744     return _oop_alias_idx == ((StoreCMNode&)n)._oop_alias_idx
 745       && StoreNode::cmp(n);
 746   }
 747   virtual uint size_of() const { return sizeof(*this); }
 748   int _oop_alias_idx;   // The alias_idx of OopStore
 749 
 750 public:
 751   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, int oop_alias_idx ) :
 752     StoreNode(c, mem, adr, at, val, oop_store, MemNode::release),
 753     _oop_alias_idx(oop_alias_idx) {
 754     assert(_oop_alias_idx >= Compile::AliasIdxRaw ||
 755            _oop_alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
 756            "bad oop alias idx");
 757   }
 758   virtual Opcodes Opcode() const;
 759   virtual Node* Identity(PhaseGVN* phase);
 760   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 761   virtual const Type* Value(PhaseGVN* phase) const;
 762   virtual BasicType memory_type() const { return T_VOID; } // unspecific
 763   int oop_alias_idx() const { return _oop_alias_idx; }
 764 };
 765 
 766 //------------------------------LoadPLockedNode---------------------------------
 767 // Load-locked a pointer from memory (either object or array).
 768 // On Sparc & Intel this is implemented as a normal pointer load.
 769 // On PowerPC and friends it's a real load-locked.
 770 class LoadPLockedNode : public LoadPNode {
 771 public:
 772   LoadPLockedNode(Node *c, Node *mem, Node *adr, MemOrd mo)
 773     : LoadPNode(c, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM, mo) {}
 774   virtual Opcodes Opcode() const;
 775   virtual Opcodes store_Opcode() const { return Opcodes::Op_StorePConditional; }
 776   virtual bool depends_only_on_test() const { return true; }
 777 };
 778 
 779 //------------------------------SCMemProjNode---------------------------------------
 780 // This class defines a projection of the memory  state of a store conditional node.
 781 // These nodes return a value, but also update memory.
 782 class SCMemProjNode : public ProjNode {
 783 public:
 784   enum {SCMEMPROJCON = (uint)-2};
 785   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 786   virtual Opcodes Opcode() const;
 787   virtual bool      is_CFG() const  { return false; }
 788   virtual const Type *bottom_type() const {return Type::MEMORY;}
 789   virtual const TypePtr *adr_type() const {
 790     Node* ctrl = in(0);
 791     if (ctrl == NULL)  return NULL; // node is dead
 792     return ctrl->in(MemNode::Memory)->adr_type();
 793   }
 794   virtual Opcodes ideal_reg() const { return Opcodes::Op_Node;} // memory projections don't have a register
 795   virtual const Type* Value(PhaseGVN* phase) const;
 796 #ifndef PRODUCT
 797   virtual void dump_spec(outputStream *st) const {};
 798 #endif
 799 };
 800 
 801 //------------------------------LoadStoreNode---------------------------
 802 // Note: is_Mem() method returns 'true' for this class.
 803 class LoadStoreNode : public Node {
 804 private:
 805   const Type* const _type;      // What kind of value is loaded?
 806   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 807   virtual uint size_of() const; // Size is bigger
 808 public:
 809   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 810   virtual bool depends_only_on_test() const { return false; }
 811   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 812 
 813   virtual const Type *bottom_type() const { return _type; }
 814   virtual Opcodes ideal_reg() const;
 815   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 816 
 817   bool result_not_used() const;
 818 };
 819 
 820 class LoadStoreConditionalNode : public LoadStoreNode {
 821 public:
 822   enum {
 823     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 824   };
 825   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 826 };
 827 
 828 //------------------------------StorePConditionalNode---------------------------
 829 // Conditionally store pointer to memory, if no change since prior
 830 // load-locked.  Sets flags for success or failure of the store.
 831 class StorePConditionalNode : public LoadStoreConditionalNode {
 832 public:
 833   StorePConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 834   virtual Opcodes Opcode() const;
 835   // Produces flags
 836   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegFlags; }
 837 };
 838 
 839 //------------------------------StoreIConditionalNode---------------------------
 840 // Conditionally store int to memory, if no change since prior
 841 // load-locked.  Sets flags for success or failure of the store.
 842 class StoreIConditionalNode : public LoadStoreConditionalNode {
 843 public:
 844   StoreIConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ii ) : LoadStoreConditionalNode(c, mem, adr, val, ii) { }
 845   virtual Opcodes Opcode() const;
 846   // Produces flags
 847   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegFlags; }
 848 };
 849 
 850 //------------------------------StoreLConditionalNode---------------------------
 851 // Conditionally store long to memory, if no change since prior
 852 // load-locked.  Sets flags for success or failure of the store.
 853 class StoreLConditionalNode : public LoadStoreConditionalNode {
 854 public:
 855   StoreLConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 856   virtual Opcodes Opcode() const;
 857   // Produces flags
 858   virtual Opcodes ideal_reg() const { return Opcodes::Op_RegFlags; }
 859 };
 860 
 861 class CompareAndSwapNode : public LoadStoreConditionalNode {
 862 private:
 863   const MemNode::MemOrd _mem_ord;
 864 public:
 865   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) {}
 866   MemNode::MemOrd order() const {
 867     return _mem_ord;
 868   }
 869 };
 870 
 871 class CompareAndExchangeNode : public LoadStoreNode {
 872 private:
 873   const MemNode::MemOrd _mem_ord;
 874 public:
 875   enum {
 876     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 877   };
 878   CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
 879     LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
 880      init_req(ExpectedIn, ex );
 881   }
 882 
 883   MemNode::MemOrd order() const {
 884     return _mem_ord;
 885   }
 886 };
 887 
 888 //------------------------------CompareAndSwapBNode---------------------------
 889 class CompareAndSwapBNode : public CompareAndSwapNode {
 890 public:
 891   CompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 892   virtual Opcodes Opcode() const;
 893 };
 894 
 895 //------------------------------CompareAndSwapSNode---------------------------
 896 class CompareAndSwapSNode : public CompareAndSwapNode {
 897 public:
 898   CompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 899   virtual Opcodes Opcode() const;
 900 };
 901 
 902 //------------------------------CompareAndSwapINode---------------------------
 903 class CompareAndSwapINode : public CompareAndSwapNode {
 904 public:
 905   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 906   virtual Opcodes Opcode() const;
 907 };
 908 
 909 //------------------------------CompareAndSwapLNode---------------------------
 910 class CompareAndSwapLNode : public CompareAndSwapNode {
 911 public:
 912   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 913   virtual Opcodes Opcode() const;
 914 };
 915 
 916 //------------------------------CompareAndSwapPNode---------------------------
 917 class CompareAndSwapPNode : public CompareAndSwapNode {
 918 public:
 919   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 920   virtual Opcodes Opcode() const;
 921 };
 922 
 923 //------------------------------CompareAndSwapNNode---------------------------
 924 class CompareAndSwapNNode : public CompareAndSwapNode {
 925 public:
 926   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 927   virtual Opcodes Opcode() const;
 928 };
 929 
 930 //------------------------------WeakCompareAndSwapBNode---------------------------
 931 class WeakCompareAndSwapBNode : public CompareAndSwapNode {
 932 public:
 933   WeakCompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 934   virtual Opcodes Opcode() const;
 935 };
 936 
 937 //------------------------------WeakCompareAndSwapSNode---------------------------
 938 class WeakCompareAndSwapSNode : public CompareAndSwapNode {
 939 public:
 940   WeakCompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 941   virtual Opcodes Opcode() const;
 942 };
 943 
 944 //------------------------------WeakCompareAndSwapINode---------------------------
 945 class WeakCompareAndSwapINode : public CompareAndSwapNode {
 946 public:
 947   WeakCompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 948   virtual Opcodes Opcode() const;
 949 };
 950 
 951 //------------------------------WeakCompareAndSwapLNode---------------------------
 952 class WeakCompareAndSwapLNode : public CompareAndSwapNode {
 953 public:
 954   WeakCompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 955   virtual Opcodes Opcode() const;
 956 };
 957 
 958 //------------------------------WeakCompareAndSwapPNode---------------------------
 959 class WeakCompareAndSwapPNode : public CompareAndSwapNode {
 960 public:
 961   WeakCompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 962   virtual Opcodes Opcode() const;
 963 };
 964 
 965 //------------------------------WeakCompareAndSwapNNode---------------------------
 966 class WeakCompareAndSwapNNode : public CompareAndSwapNode {
 967 public:
 968   WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 969   virtual Opcodes Opcode() const;
 970 };
 971 
 972 //------------------------------CompareAndExchangeBNode---------------------------
 973 class CompareAndExchangeBNode : public CompareAndExchangeNode {
 974 public:
 975   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) { }
 976   virtual Opcodes Opcode() const;
 977 };
 978 
 979 
 980 //------------------------------CompareAndExchangeSNode---------------------------
 981 class CompareAndExchangeSNode : public CompareAndExchangeNode {
 982 public:
 983   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) { }
 984   virtual Opcodes Opcode() const;
 985 };
 986 
 987 //------------------------------CompareAndExchangeLNode---------------------------
 988 class CompareAndExchangeLNode : public CompareAndExchangeNode {
 989 public:
 990   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) { }
 991   virtual Opcodes Opcode() const;
 992 };
 993 
 994 
 995 //------------------------------CompareAndExchangeINode---------------------------
 996 class CompareAndExchangeINode : public CompareAndExchangeNode {
 997 public:
 998   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) { }
 999   virtual Opcodes Opcode() const;
1000 };
1001 
1002 
1003 //------------------------------CompareAndExchangePNode---------------------------
1004 class CompareAndExchangePNode : public CompareAndExchangeNode {
1005 public:
1006   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) { }
1007   virtual Opcodes Opcode() const;
1008 };
1009 
1010 //------------------------------CompareAndExchangeNNode---------------------------
1011 class CompareAndExchangeNNode : public CompareAndExchangeNode {
1012 public:
1013   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) { }
1014   virtual Opcodes Opcode() const;
1015 };
1016 
1017 //------------------------------GetAndAddBNode---------------------------
1018 class GetAndAddBNode : public LoadStoreNode {
1019 public:
1020   GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1021   virtual Opcodes Opcode() const;
1022 };
1023 
1024 //------------------------------GetAndAddSNode---------------------------
1025 class GetAndAddSNode : public LoadStoreNode {
1026 public:
1027   GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1028   virtual Opcodes Opcode() const;
1029 };
1030 
1031 //------------------------------GetAndAddINode---------------------------
1032 class GetAndAddINode : public LoadStoreNode {
1033 public:
1034   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1035   virtual Opcodes Opcode() const;
1036 };
1037 
1038 //------------------------------GetAndAddLNode---------------------------
1039 class GetAndAddLNode : public LoadStoreNode {
1040 public:
1041   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1042   virtual Opcodes Opcode() const;
1043 };
1044 
1045 //------------------------------GetAndSetBNode---------------------------
1046 class GetAndSetBNode : public LoadStoreNode {
1047 public:
1048   GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1049   virtual Opcodes Opcode() const;
1050 };
1051 
1052 //------------------------------GetAndSetSNode---------------------------
1053 class GetAndSetSNode : public LoadStoreNode {
1054 public:
1055   GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1056   virtual Opcodes Opcode() const;
1057 };
1058 
1059 //------------------------------GetAndSetINode---------------------------
1060 class GetAndSetINode : public LoadStoreNode {
1061 public:
1062   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1063   virtual Opcodes Opcode() const;
1064 };
1065 
1066 //------------------------------GetAndSetLNode---------------------------
1067 class GetAndSetLNode : public LoadStoreNode {
1068 public:
1069   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1070   virtual Opcodes Opcode() const;
1071 };
1072 
1073 //------------------------------GetAndSetPNode---------------------------
1074 class GetAndSetPNode : public LoadStoreNode {
1075 public:
1076   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1077   virtual Opcodes Opcode() const;
1078 };
1079 
1080 //------------------------------GetAndSetNNode---------------------------
1081 class GetAndSetNNode : public LoadStoreNode {
1082 public:
1083   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1084   virtual Opcodes Opcode() const;
1085 };
1086 
1087 //------------------------------ClearArray-------------------------------------
1088 class ClearArrayNode: public Node {
1089 private:
1090   bool _is_large;
1091 public:
1092   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, bool is_large)
1093     : Node(ctrl,arymem,word_cnt,base), _is_large(is_large) {
1094     init_class_id(Class_ClearArray);
1095   }
1096   virtual Opcodes     Opcode() const;
1097   virtual const Type *bottom_type() const { return Type::MEMORY; }
1098   // ClearArray modifies array elements, and so affects only the
1099   // array memory addressed by the bottom_type of its base address.
1100   virtual const class TypePtr *adr_type() const;
1101   virtual Node* Identity(PhaseGVN* phase);
1102   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1103   virtual uint match_edge(uint idx) const;
1104   bool is_large() const { return _is_large; }
1105 
1106   // Clear the given area of an object or array.
1107   // The start offset must always be aligned mod BytesPerInt.
1108   // The end offset must always be aligned mod BytesPerLong.
1109   // Return the new memory.
1110   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1111                             intptr_t start_offset,
1112                             intptr_t end_offset,
1113                             PhaseGVN* phase);
1114   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1115                             intptr_t start_offset,
1116                             Node* end_offset,
1117                             PhaseGVN* phase);
1118   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1119                             Node* start_offset,
1120                             Node* end_offset,
1121                             PhaseGVN* phase);
1122   // Return allocation input memory edge if it is different instance
1123   // or itself if it is the one we are looking for.
1124   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
1125 };
1126 
1127 //------------------------------MemBar-----------------------------------------
1128 // There are different flavors of Memory Barriers to match the Java Memory
1129 // Model.  Monitor-enter and volatile-load act as Aquires: no following ref
1130 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
1131 // volatile-load.  Monitor-exit and volatile-store act as Release: no
1132 // preceding ref can be moved to after them.  We insert a MemBar-Release
1133 // before a FastUnlock or volatile-store.  All volatiles need to be
1134 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
1135 // separate it from any following volatile-load.
1136 class MemBarNode: public MultiNode {
1137   virtual uint hash() const ;                  // { return NO_HASH; }
1138   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
1139 
1140   virtual uint size_of() const { return sizeof(*this); }
1141   // Memory type this node is serializing.  Usually either rawptr or bottom.
1142   const TypePtr* _adr_type;
1143 
1144 public:
1145   enum {
1146     Precedent = TypeFunc::Parms  // optional edge to force precedence
1147   };
1148   MemBarNode(Compile* C, int alias_idx, Node* precedent);
1149   virtual Opcodes Opcode() const = 0;
1150   virtual const class TypePtr *adr_type() const { return _adr_type; }
1151   virtual const Type* Value(PhaseGVN* phase) const;
1152   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1153   virtual uint match_edge(uint idx) const { return 0; }
1154   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
1155   virtual Node *match( const ProjNode *proj, const Matcher *m );
1156   // Factory method.  Builds a wide or narrow membar.
1157   // Optional 'precedent' becomes an extra edge if not null.
1158   static MemBarNode* make(Compile* C, Opcodes opcode,
1159                           int alias_idx = Compile::AliasIdxBot,
1160                           Node* precedent = NULL);
1161 };
1162 
1163 // "Acquire" - no following ref can move before (but earlier refs can
1164 // follow, like an early Load stalled in cache).  Requires multi-cpu
1165 // visibility.  Inserted after a volatile load.
1166 class MemBarAcquireNode: public MemBarNode {
1167 public:
1168   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1169     : MemBarNode(C, alias_idx, precedent) {}
1170   virtual Opcodes Opcode() const;
1171 };
1172 
1173 // "Acquire" - no following ref can move before (but earlier refs can
1174 // follow, like an early Load stalled in cache).  Requires multi-cpu
1175 // visibility.  Inserted independ of any load, as required
1176 // for intrinsic Unsafe.loadFence().
1177 class LoadFenceNode: public MemBarNode {
1178 public:
1179   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
1180     : MemBarNode(C, alias_idx, precedent) {}
1181   virtual Opcodes Opcode() const;
1182 };
1183 
1184 // "Release" - no earlier ref can move after (but later refs can move
1185 // up, like a speculative pipelined cache-hitting Load).  Requires
1186 // multi-cpu visibility.  Inserted before a volatile store.
1187 class MemBarReleaseNode: public MemBarNode {
1188 public:
1189   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1190     : MemBarNode(C, alias_idx, precedent) {}
1191   virtual Opcodes Opcode() const;
1192 };
1193 
1194 // "Release" - no earlier ref can move after (but later refs can move
1195 // up, like a speculative pipelined cache-hitting Load).  Requires
1196 // multi-cpu visibility.  Inserted independent of any store, as required
1197 // for intrinsic Unsafe.storeFence().
1198 class StoreFenceNode: public MemBarNode {
1199 public:
1200   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1201     : MemBarNode(C, alias_idx, precedent) {}
1202   virtual Opcodes Opcode() const;
1203 };
1204 
1205 // "Acquire" - no following ref can move before (but earlier refs can
1206 // follow, like an early Load stalled in cache).  Requires multi-cpu
1207 // visibility.  Inserted after a FastLock.
1208 class MemBarAcquireLockNode: public MemBarNode {
1209 public:
1210   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1211     : MemBarNode(C, alias_idx, precedent) {}
1212   virtual Opcodes Opcode() const;
1213 };
1214 
1215 // "Release" - no earlier ref can move after (but later refs can move
1216 // up, like a speculative pipelined cache-hitting Load).  Requires
1217 // multi-cpu visibility.  Inserted before a FastUnLock.
1218 class MemBarReleaseLockNode: public MemBarNode {
1219 public:
1220   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1221     : MemBarNode(C, alias_idx, precedent) {}
1222   virtual Opcodes Opcode() const;
1223 };
1224 
1225 class MemBarStoreStoreNode: public MemBarNode {
1226 public:
1227   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1228     : MemBarNode(C, alias_idx, precedent) {
1229     init_class_id(Class_MemBarStoreStore);
1230   }
1231   virtual Opcodes Opcode() const;
1232 };
1233 
1234 // Ordering between a volatile store and a following volatile load.
1235 // Requires multi-CPU visibility?
1236 class MemBarVolatileNode: public MemBarNode {
1237 public:
1238   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1239     : MemBarNode(C, alias_idx, precedent) {}
1240   virtual Opcodes Opcode() const;
1241 };
1242 
1243 // Ordering within the same CPU.  Used to order unsafe memory references
1244 // inside the compiler when we lack alias info.  Not needed "outside" the
1245 // compiler because the CPU does all the ordering for us.
1246 class MemBarCPUOrderNode: public MemBarNode {
1247 public:
1248   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1249     : MemBarNode(C, alias_idx, precedent) {}
1250   virtual Opcodes Opcode() const;
1251   virtual Opcodes ideal_reg() const { return Opcodes::Op_Node; } // not matched in the AD file
1252 };
1253 
1254 class OnSpinWaitNode: public MemBarNode {
1255 public:
1256   OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
1257     : MemBarNode(C, alias_idx, precedent) {}
1258   virtual Opcodes Opcode() const;
1259 };
1260 
1261 // Isolation of object setup after an AllocateNode and before next safepoint.
1262 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1263 class InitializeNode: public MemBarNode {
1264   friend class AllocateNode;
1265 
1266   enum {
1267     Incomplete    = 0,
1268     Complete      = 1,
1269     WithArraycopy = 2
1270   };
1271   int _is_complete;
1272 
1273   bool _does_not_escape;
1274 
1275 public:
1276   enum {
1277     Control    = TypeFunc::Control,
1278     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1279     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1280     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1281   };
1282 
1283   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1284   virtual Opcodes Opcode() const;
1285   virtual uint size_of() const { return sizeof(*this); }
1286   virtual Opcodes ideal_reg() const { return Opcodes::Op_Node; } // not matched in the AD file
1287   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1288 
1289   // Manage incoming memory edges via a MergeMem on in(Memory):
1290   Node* memory(uint alias_idx);
1291 
1292   // The raw memory edge coming directly from the Allocation.
1293   // The contents of this memory are *always* all-zero-bits.
1294   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1295 
1296   // Return the corresponding allocation for this initialization (or null if none).
1297   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1298   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1299   AllocateNode* allocation();
1300 
1301   // Anything other than zeroing in this init?
1302   bool is_non_zero();
1303 
1304   // An InitializeNode must completed before macro expansion is done.
1305   // Completion requires that the AllocateNode must be followed by
1306   // initialization of the new memory to zero, then to any initializers.
1307   bool is_complete() { return _is_complete != Incomplete; }
1308   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1309 
1310   // Mark complete.  (Must not yet be complete.)
1311   void set_complete(PhaseGVN* phase);
1312   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1313 
1314   bool does_not_escape() { return _does_not_escape; }
1315   void set_does_not_escape() { _does_not_escape = true; }
1316 
1317 #ifdef ASSERT
1318   // ensure all non-degenerate stores are ordered and non-overlapping
1319   bool stores_are_sane(PhaseTransform* phase);
1320 #endif //ASSERT
1321 
1322   // See if this store can be captured; return offset where it initializes.
1323   // Return 0 if the store cannot be moved (any sort of problem).
1324   intptr_t can_capture_store(StoreNode* st, PhaseTransform* phase, bool can_reshape);
1325 
1326   // Capture another store; reformat it to write my internal raw memory.
1327   // Return the captured copy, else NULL if there is some sort of problem.
1328   Node* capture_store(StoreNode* st, intptr_t start, PhaseTransform* phase, bool can_reshape);
1329 
1330   // Find captured store which corresponds to the range [start..start+size).
1331   // Return my own memory projection (meaning the initial zero bits)
1332   // if there is no such store.  Return NULL if there is a problem.
1333   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);
1334 
1335   // Called when the associated AllocateNode is expanded into CFG.
1336   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1337                         intptr_t header_size, Node* size_in_bytes,
1338                         PhaseGVN* phase);
1339 
1340  private:
1341   void remove_extra_zeroes();
1342 
1343   // Find out where a captured store should be placed (or already is placed).
1344   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1345                                      PhaseTransform* phase);
1346 
1347   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);
1348 
1349   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);
1350 
1351   bool detect_init_independence(Node* n, int& count);
1352 
1353   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1354                                PhaseGVN* phase);
1355 
1356   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1357 };
1358 
1359 //------------------------------MergeMem---------------------------------------
1360 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1361 class MergeMemNode: public Node {
1362   virtual uint hash() const ;                  // { return NO_HASH; }
1363   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
1364   friend class MergeMemStream;
1365   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1366 
1367 public:
1368   // If the input is a whole memory state, clone it with all its slices intact.
1369   // Otherwise, make a new memory state with just that base memory input.
1370   // In either case, the result is a newly created MergeMem.
1371   static MergeMemNode* make(Node* base_memory);
1372 
1373   virtual Opcodes Opcode() const;
1374   virtual Node* Identity(PhaseGVN* phase);
1375   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1376   virtual Opcodes ideal_reg() const { return Opcodes::NotAMachineReg; }
1377   virtual uint match_edge(uint idx) const { return 0; }
1378   virtual const RegMask &out_RegMask() const;
1379   virtual const Type *bottom_type() const { return Type::MEMORY; }
1380   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1381   // sparse accessors
1382   // Fetch the previously stored "set_memory_at", or else the base memory.
1383   // (Caller should clone it if it is a phi-nest.)
1384   Node* memory_at(uint alias_idx) const;
1385   // set the memory, regardless of its previous value
1386   void set_memory_at(uint alias_idx, Node* n);
1387   // the "base" is the memory that provides the non-finite support
1388   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1389   // warning: setting the base can implicitly set any of the other slices too
1390   void set_base_memory(Node* def);
1391   // sentinel value which denotes a copy of the base memory:
1392   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1393   static Node* make_empty_memory(); // where the sentinel comes from
1394   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1395   // hook for the iterator, to perform any necessary setup
1396   void iteration_setup(const MergeMemNode* other = NULL);
1397   // push sentinels until I am at least as long as the other (semantic no-op)
1398   void grow_to_match(const MergeMemNode* other);
1399   bool verify_sparse() const PRODUCT_RETURN0;
1400 #ifndef PRODUCT
1401   virtual void dump_spec(outputStream *st) const;
1402 #endif
1403 };
1404 
1405 class MergeMemStream : public StackObj {
1406  private:
1407   MergeMemNode*       _mm;
1408   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1409   Node*               _mm_base;  // loop-invariant base memory of _mm
1410   int                 _idx;
1411   int                 _cnt;
1412   Node*               _mem;
1413   Node*               _mem2;
1414   int                 _cnt2;
1415 
1416   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {
1417     // subsume_node will break sparseness at times, whenever a memory slice
1418     // folds down to a copy of the base ("fat") memory.  In such a case,
1419     // the raw edge will update to base, although it should be top.
1420     // This iterator will recognize either top or base_memory as an
1421     // "empty" slice.  See is_empty, is_empty2, and next below.
1422     //
1423     // The sparseness property is repaired in MergeMemNode::Ideal.
1424     // As long as access to a MergeMem goes through this iterator
1425     // or the memory_at accessor, flaws in the sparseness will
1426     // never be observed.
1427     //
1428     // Also, iteration_setup repairs sparseness.
1429     assert(mm->verify_sparse(), "please, no dups of base");
1430     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");
1431 
1432     _mm  = mm;
1433     _mm_base = mm->base_memory();
1434     _mm2 = mm2;
1435     _cnt = mm->req();
1436     _idx = Compile::AliasIdxBot-1; // start at the base memory
1437     _mem = NULL;
1438     _mem2 = NULL;
1439   }
1440 
1441 #ifdef ASSERT
1442   Node* check_memory() const {
1443     if (at_base_memory())
1444       return _mm->base_memory();
1445     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1446       return _mm->memory_at(_idx);
1447     else
1448       return _mm_base;
1449   }
1450   Node* check_memory2() const {
1451     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1452   }
1453 #endif
1454 
1455   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1456   void assert_synch() const {
1457     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1458            "no side-effects except through the stream");
1459   }
1460 
1461  public:
1462 
1463   // expected usages:
1464   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1465   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1466 
1467   // iterate over one merge
1468   MergeMemStream(MergeMemNode* mm) {
1469     mm->iteration_setup();
1470     init(mm);
1471     debug_only(_cnt2 = 999);
1472   }
1473   // iterate in parallel over two merges
1474   // only iterates through non-empty elements of mm2
1475   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1476     assert(mm2, "second argument must be a MergeMem also");
1477     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1478     mm->iteration_setup(mm2);
1479     init(mm, mm2);
1480     _cnt2 = mm2->req();
1481   }
1482 #ifdef ASSERT
1483   ~MergeMemStream() {
1484     assert_synch();
1485   }
1486 #endif
1487 
1488   MergeMemNode* all_memory() const {
1489     return _mm;
1490   }
1491   Node* base_memory() const {
1492     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1493     return _mm_base;
1494   }
1495   const MergeMemNode* all_memory2() const {
1496     assert(_mm2 != NULL, "");
1497     return _mm2;
1498   }
1499   bool at_base_memory() const {
1500     return _idx == Compile::AliasIdxBot;
1501   }
1502   int alias_idx() const {
1503     assert(_mem, "must call next 1st");
1504     return _idx;
1505   }
1506 
1507   const TypePtr* adr_type() const {
1508     return Compile::current()->get_adr_type(alias_idx());
1509   }
1510 
1511   const TypePtr* adr_type(Compile* C) const {
1512     return C->get_adr_type(alias_idx());
1513   }
1514   bool is_empty() const {
1515     assert(_mem, "must call next 1st");
1516     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1517     return _mem->is_top();
1518   }
1519   bool is_empty2() const {
1520     assert(_mem2, "must call next 1st");
1521     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1522     return _mem2->is_top();
1523   }
1524   Node* memory() const {
1525     assert(!is_empty(), "must not be empty");
1526     assert_synch();
1527     return _mem;
1528   }
1529   // get the current memory, regardless of empty or non-empty status
1530   Node* force_memory() const {
1531     assert(!is_empty() || !at_base_memory(), "");
1532     // Use _mm_base to defend against updates to _mem->base_memory().
1533     Node *mem = _mem->is_top() ? _mm_base : _mem;
1534     assert(mem == check_memory(), "");
1535     return mem;
1536   }
1537   Node* memory2() const {
1538     assert(_mem2 == check_memory2(), "");
1539     return _mem2;
1540   }
1541   void set_memory(Node* mem) {
1542     if (at_base_memory()) {
1543       // Note that this does not change the invariant _mm_base.
1544       _mm->set_base_memory(mem);
1545     } else {
1546       _mm->set_memory_at(_idx, mem);
1547     }
1548     _mem = mem;
1549     assert_synch();
1550   }
1551 
1552   // Recover from a side effect to the MergeMemNode.
1553   void set_memory() {
1554     _mem = _mm->in(_idx);
1555   }
1556 
1557   bool next()  { return next(false); }
1558   bool next2() { return next(true); }
1559 
1560   bool next_non_empty()  { return next_non_empty(false); }
1561   bool next_non_empty2() { return next_non_empty(true); }
1562   // next_non_empty2 can yield states where is_empty() is true
1563 
1564  private:
1565   // find the next item, which might be empty
1566   bool next(bool have_mm2) {
1567     assert((_mm2 != NULL) == have_mm2, "use other next");
1568     assert_synch();
1569     if (++_idx < _cnt) {
1570       // Note:  This iterator allows _mm to be non-sparse.
1571       // It behaves the same whether _mem is top or base_memory.
1572       _mem = _mm->in(_idx);
1573       if (have_mm2)
1574         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1575       return true;
1576     }
1577     return false;
1578   }
1579 
1580   // find the next non-empty item
1581   bool next_non_empty(bool have_mm2) {
1582     while (next(have_mm2)) {
1583       if (!is_empty()) {
1584         // make sure _mem2 is filled in sensibly
1585         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1586         return true;
1587       } else if (have_mm2 && !is_empty2()) {
1588         return true;   // is_empty() == true
1589       }
1590     }
1591     return false;
1592   }
1593 };
1594 
1595 //------------------------------Prefetch---------------------------------------
1596 
1597 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1598 class PrefetchAllocationNode : public Node {
1599 public:
1600   PrefetchAllocationNode(Node *mem, Node *adr) : Node(0,mem,adr) {}
1601   virtual Opcodes Opcode() const;
1602   virtual Opcodes ideal_reg() const { return Opcodes::NotAMachineReg; }
1603   virtual uint match_edge(uint idx) const { return idx==2; }
1604   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1605 };
1606 
1607 #endif // SHARE_VM_OPTO_MEMNODE_HPP