1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_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 protected:
  43 #ifdef ASSERT
  44   const TypePtr* _adr_type;     // What kind of memory is being addressed?
  45 #endif
  46   virtual uint size_of() const; // Size is bigger (ASSERT only)
  47 public:
  48   enum { Control,               // When is it safe to do this load?
  49          Memory,                // Chunk of memory is being loaded from
  50          Address,               // Actually address, derived from base
  51          ValueIn,               // Value to store
  52          OopStore               // Preceeding oop store, only in StoreCM
  53   };
  54   typedef enum { unordered = 0,
  55                  acquire,       // Load has to acquire or be succeeded by MemBarAcquire.
  56                  release        // Store has to release or be preceded by MemBarRelease.
  57   } MemOrd;
  58 protected:
  59   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at )
  60     : Node(c0,c1,c2   ) {
  61     init_class_id(Class_Mem);
  62     debug_only(_adr_type=at; adr_type();)
  63   }
  64   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 )
  65     : Node(c0,c1,c2,c3) {
  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, Node *c4)
  70     : Node(c0,c1,c2,c3,c4) {
  71     init_class_id(Class_Mem);
  72     debug_only(_adr_type=at; adr_type();)
  73   }
  74 
  75 public:
  76   // Helpers for the optimizer.  Documented in memnode.cpp.
  77   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
  78                                       Node* p2, AllocateNode* a2,
  79                                       PhaseTransform* phase);
  80   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
  81 
  82   static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
  83   static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
  84   // This one should probably be a phase-specific function:
  85   static bool all_controls_dominate(Node* dom, Node* sub);
  86 
  87   // Find any cast-away of null-ness and keep its control.
  88   static  Node *Ideal_common_DU_postCCP( PhaseCCP *ccp, Node* n, Node* adr );
  89   virtual Node *Ideal_DU_postCCP( PhaseCCP *ccp );
  90 
  91   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
  92 
  93   // Shared code for Ideal methods:
  94   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.
  95 
  96   // Helper function for adr_type() implementations.
  97   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);
  98 
  99   // Raw access function, to allow copying of adr_type efficiently in
 100   // product builds and retain the debug info for debug builds.
 101   const TypePtr *raw_adr_type() const {
 102 #ifdef ASSERT
 103     return _adr_type;
 104 #else
 105     return 0;
 106 #endif
 107   }
 108 
 109   // Map a load or store opcode to its corresponding store opcode.
 110   // (Return -1 if unknown.)
 111   virtual int store_Opcode() const { return -1; }
 112 
 113   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 114   virtual BasicType memory_type() const = 0;
 115   virtual int memory_size() const {
 116 #ifdef ASSERT
 117     return type2aelembytes(memory_type(), true);
 118 #else
 119     return type2aelembytes(memory_type());
 120 #endif
 121   }
 122 
 123   // Search through memory states which precede this node (load or store).
 124   // Look for an exact match for the address, with no intervening
 125   // aliased stores.
 126   Node* find_previous_store(PhaseTransform* phase);
 127 
 128   // Can this node (load or store) accurately see a stored value in
 129   // the given memory state?  (The state may or may not be in(Memory).)
 130   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;
 131 
 132 #ifndef PRODUCT
 133   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 134   virtual void dump_spec(outputStream *st) const;
 135 #endif
 136 };
 137 
 138 //------------------------------LoadNode---------------------------------------
 139 // Load value; requires Memory and Address
 140 class LoadNode : public MemNode {
 141 private:
 142   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 143   // loads that can be reordered, and such requiring acquire semantics to
 144   // adhere to the Java specification.  The required behaviour is stored in
 145   // this field.
 146   const MemOrd _mo;
 147 
 148 protected:
 149   virtual uint cmp(const Node &n) const;
 150   virtual uint size_of() const; // Size is bigger
 151   const Type* const _type;      // What kind of value is loaded?
 152 public:
 153 
 154   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo)
 155     : MemNode(c,mem,adr,at), _type(rt), _mo(mo) {
 156     init_class_id(Class_Load);
 157   }
 158   inline bool is_unordered() const { return !is_acquire(); }
 159   inline bool is_acquire() const {
 160     assert(_mo == unordered || _mo == acquire, "unexpected");
 161     return _mo == acquire;
 162   }
 163 
 164   // Polymorphic factory method:
 165    static Node* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 166                      const TypePtr* at, const Type *rt, BasicType bt, MemOrd mo);
 167 
 168   virtual uint hash()   const;  // Check the type
 169 
 170   // Handle algebraic identities here.  If we have an identity, return the Node
 171   // we are equivalent to.  We look for Load of a Store.
 172   virtual Node *Identity( PhaseTransform *phase );
 173 
 174   // If the load is from Field memory and the pointer is non-null, we can
 175   // zero out the control input.
 176   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 177 
 178   // Split instance field load through Phi.
 179   Node* split_through_phi(PhaseGVN *phase);
 180 
 181   // Recover original value from boxed values
 182   Node *eliminate_autobox(PhaseGVN *phase);
 183 
 184   // Compute a new Type for this node.  Basically we just do the pre-check,
 185   // then call the virtual add() to set the type.
 186   virtual const Type *Value( PhaseTransform *phase ) const;
 187 
 188   // Common methods for LoadKlass and LoadNKlass nodes.
 189   const Type *klass_value_common( PhaseTransform *phase ) const;
 190   Node *klass_identity_common( PhaseTransform *phase );
 191 
 192   virtual uint ideal_reg() const;
 193   virtual const Type *bottom_type() const;
 194   // Following method is copied from TypeNode:
 195   void set_type(const Type* t) {
 196     assert(t != NULL, "sanity");
 197     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 198     *(const Type**)&_type = t;   // cast away const-ness
 199     // If this node is in the hash table, make sure it doesn't need a rehash.
 200     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 201   }
 202   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
 203 
 204   // Do not match memory edge
 205   virtual uint match_edge(uint idx) const;
 206 
 207   // Map a load opcode to its corresponding store opcode.
 208   virtual int store_Opcode() const = 0;
 209 
 210   // Check if the load's memory input is a Phi node with the same control.
 211   bool is_instance_field_load_with_local_phi(Node* ctrl);
 212 
 213 #ifndef PRODUCT
 214   virtual void dump_spec(outputStream *st) const;
 215 #endif
 216 #ifdef ASSERT
 217   // Helper function to allow a raw load without control edge for some cases
 218   static bool is_immutable_value(Node* adr);
 219 #endif
 220 protected:
 221   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 222                                      ciKlass* klass) const;
 223   // depends_only_on_test is almost always true, and needs to be almost always
 224   // true to enable key hoisting & commoning optimizations.  However, for the
 225   // special case of RawPtr loads from TLS top & end, and other loads performed by
 226   // GC barriers, the control edge carries the dependence preventing hoisting past
 227   // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
 228   // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
 229   // which produce results (new raw memory state) inside of loops preventing all
 230   // manner of other optimizations).  Basically, it's ugly but so is the alternative.
 231   // See comment in macro.cpp, around line 125 expand_allocate_common().
 232   virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
 233 
 234 };
 235 
 236 //------------------------------LoadBNode--------------------------------------
 237 // Load a byte (8bits signed) from memory
 238 class LoadBNode : public LoadNode {
 239 public:
 240   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo)
 241     : LoadNode(c, mem, adr, at, ti, mo) {}
 242   virtual int Opcode() const;
 243   virtual uint ideal_reg() const { return Op_RegI; }
 244   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 245   virtual const Type *Value(PhaseTransform *phase) const;
 246   virtual int store_Opcode() const { return Op_StoreB; }
 247   virtual BasicType memory_type() const { return T_BYTE; }
 248 };
 249 
 250 //------------------------------LoadUBNode-------------------------------------
 251 // Load a unsigned byte (8bits unsigned) from memory
 252 class LoadUBNode : public LoadNode {
 253 public:
 254   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo)
 255     : LoadNode(c, mem, adr, at, ti, mo) {}
 256   virtual int Opcode() const;
 257   virtual uint ideal_reg() const { return Op_RegI; }
 258   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 259   virtual const Type *Value(PhaseTransform *phase) const;
 260   virtual int store_Opcode() const { return Op_StoreB; }
 261   virtual BasicType memory_type() const { return T_BYTE; }
 262 };
 263 
 264 //------------------------------LoadUSNode-------------------------------------
 265 // Load an unsigned short/char (16bits unsigned) from memory
 266 class LoadUSNode : public LoadNode {
 267 public:
 268   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo)
 269     : LoadNode(c, mem, adr, at, ti, mo) {}
 270   virtual int Opcode() const;
 271   virtual uint ideal_reg() const { return Op_RegI; }
 272   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 273   virtual const Type *Value(PhaseTransform *phase) const;
 274   virtual int store_Opcode() const { return Op_StoreC; }
 275   virtual BasicType memory_type() const { return T_CHAR; }
 276 };
 277 
 278 //------------------------------LoadSNode--------------------------------------
 279 // Load a short (16bits signed) from memory
 280 class LoadSNode : public LoadNode {
 281 public:
 282   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo)
 283     : LoadNode(c, mem, adr, at, ti, mo) {}
 284   virtual int Opcode() const;
 285   virtual uint ideal_reg() const { return Op_RegI; }
 286   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 287   virtual const Type *Value(PhaseTransform *phase) const;
 288   virtual int store_Opcode() const { return Op_StoreC; }
 289   virtual BasicType memory_type() const { return T_SHORT; }
 290 };
 291 
 292 //------------------------------LoadINode--------------------------------------
 293 // Load an integer from memory
 294 class LoadINode : public LoadNode {
 295 public:
 296   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo)
 297     : LoadNode(c, mem, adr, at, ti, mo) {}
 298   virtual int Opcode() const;
 299   virtual uint ideal_reg() const { return Op_RegI; }
 300   virtual int store_Opcode() const { return Op_StoreI; }
 301   virtual BasicType memory_type() const { return T_INT; }
 302 };
 303 
 304 //------------------------------LoadRangeNode----------------------------------
 305 // Load an array length from the array
 306 class LoadRangeNode : public LoadINode {
 307 public:
 308   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 309     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
 310   virtual int Opcode() const;
 311   virtual const Type *Value( PhaseTransform *phase ) const;
 312   virtual Node *Identity( PhaseTransform *phase );
 313   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 314 };
 315 
 316 //------------------------------LoadLNode--------------------------------------
 317 // Load a long from memory
 318 class LoadLNode : public LoadNode {
 319   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 320   virtual uint cmp( const Node &n ) const {
 321     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 322       && LoadNode::cmp(n);
 323   }
 324   virtual uint size_of() const { return sizeof(*this); }
 325   const bool _require_atomic_access;  // is piecewise load forbidden?
 326 
 327 public:
 328   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 329             MemOrd mo, bool require_atomic_access = false)
 330     : LoadNode(c, mem, adr, at, tl, mo), _require_atomic_access(require_atomic_access) {}
 331   virtual int Opcode() const;
 332   virtual uint ideal_reg() const { return Op_RegL; }
 333   virtual int store_Opcode() const { return Op_StoreL; }
 334   virtual BasicType memory_type() const { return T_LONG; }
 335   bool require_atomic_access() { return _require_atomic_access; }
 336   static LoadLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 337                                 const Type* rt, MemOrd mo);
 338 #ifndef PRODUCT
 339   virtual void dump_spec(outputStream *st) const {
 340     LoadNode::dump_spec(st);
 341     if (_require_atomic_access)  st->print(" Atomic!");
 342   }
 343 #endif
 344 };
 345 
 346 //------------------------------LoadL_unalignedNode----------------------------
 347 // Load a long from unaligned memory
 348 class LoadL_unalignedNode : public LoadLNode {
 349 public:
 350   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo)
 351     : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo) {}
 352   virtual int Opcode() const;
 353 };
 354 
 355 //------------------------------LoadFNode--------------------------------------
 356 // Load a float (64 bits) from memory
 357 class LoadFNode : public LoadNode {
 358 public:
 359   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo)
 360     : LoadNode(c, mem, adr, at, t, mo) {}
 361   virtual int Opcode() const;
 362   virtual uint ideal_reg() const { return Op_RegF; }
 363   virtual int store_Opcode() const { return Op_StoreF; }
 364   virtual BasicType memory_type() const { return T_FLOAT; }
 365 };
 366 
 367 //------------------------------LoadDNode--------------------------------------
 368 // Load a double (64 bits) from memory
 369 class LoadDNode : public LoadNode {
 370   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 371   virtual uint cmp( const Node &n ) const {
 372     return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
 373       && LoadNode::cmp(n);
 374   }
 375   virtual uint size_of() const { return sizeof(*this); }
 376   const bool _require_atomic_access;  // is piecewise load forbidden?
 377 
 378 public:
 379   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
 380             MemOrd mo, bool require_atomic_access = false)
 381     : LoadNode(c, mem, adr, at, t, mo), _require_atomic_access(require_atomic_access) {}
 382   virtual int Opcode() const;
 383   virtual uint ideal_reg() const { return Op_RegD; }
 384   virtual int store_Opcode() const { return Op_StoreD; }
 385   virtual BasicType memory_type() const { return T_DOUBLE; }
 386   bool require_atomic_access() { return _require_atomic_access; }
 387   static LoadDNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 388                                 const Type* rt, MemOrd mo);
 389 #ifndef PRODUCT
 390   virtual void dump_spec(outputStream *st) const {
 391     LoadNode::dump_spec(st);
 392     if (_require_atomic_access)  st->print(" Atomic!");
 393   }
 394 #endif
 395 };
 396 
 397 //------------------------------LoadD_unalignedNode----------------------------
 398 // Load a double from unaligned memory
 399 class LoadD_unalignedNode : public LoadDNode {
 400 public:
 401   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo)
 402     : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo) {}
 403   virtual int Opcode() const;
 404 };
 405 
 406 //------------------------------LoadPNode--------------------------------------
 407 // Load a pointer from memory (either object or array)
 408 class LoadPNode : public LoadNode {
 409 public:
 410   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo)
 411     : LoadNode(c, mem, adr, at, t, mo) {}
 412   virtual int Opcode() const;
 413   virtual uint ideal_reg() const { return Op_RegP; }
 414   virtual int store_Opcode() const { return Op_StoreP; }
 415   virtual BasicType memory_type() const { return T_ADDRESS; }
 416 };
 417 
 418 
 419 //------------------------------LoadNNode--------------------------------------
 420 // Load a narrow oop from memory (either object or array)
 421 class LoadNNode : public LoadNode {
 422 public:
 423   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo)
 424     : LoadNode(c, mem, adr, at, t, mo) {}
 425   virtual int Opcode() const;
 426   virtual uint ideal_reg() const { return Op_RegN; }
 427   virtual int store_Opcode() const { return Op_StoreN; }
 428   virtual BasicType memory_type() const { return T_NARROWOOP; }
 429 };
 430 
 431 //------------------------------LoadKlassNode----------------------------------
 432 // Load a Klass from an object
 433 class LoadKlassNode : public LoadPNode {
 434 public:
 435   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
 436     : LoadPNode(c, mem, adr, at, tk, mo) {}
 437   virtual int Opcode() const;
 438   virtual const Type *Value( PhaseTransform *phase ) const;
 439   virtual Node *Identity( PhaseTransform *phase );
 440   virtual bool depends_only_on_test() const { return true; }
 441 
 442   // Polymorphic factory method:
 443   static Node* make( PhaseGVN& gvn, Node *mem, Node *adr, const TypePtr* at,
 444                      const TypeKlassPtr *tk = TypeKlassPtr::OBJECT );
 445 };
 446 
 447 //------------------------------LoadNKlassNode---------------------------------
 448 // Load a narrow Klass from an object.
 449 class LoadNKlassNode : public LoadNNode {
 450 public:
 451   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, MemOrd mo)
 452     : LoadNNode(c, mem, adr, at, tk, mo) {}
 453   virtual int Opcode() const;
 454   virtual uint ideal_reg() const { return Op_RegN; }
 455   virtual int store_Opcode() const { return Op_StoreNKlass; }
 456   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 457 
 458   virtual const Type *Value( PhaseTransform *phase ) const;
 459   virtual Node *Identity( PhaseTransform *phase );
 460   virtual bool depends_only_on_test() const { return true; }
 461 };
 462 
 463 
 464 //------------------------------StoreNode--------------------------------------
 465 // Store value; requires Store, Address and Value
 466 class StoreNode : public MemNode {
 467 private:
 468   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 469   // stores that can be reordered, and such requiring release semantics to
 470   // adhere to the Java specification.  The required behaviour is stored in
 471   // this field.
 472   const MemOrd _mo;
 473   // Needed for proper cloning.
 474   virtual uint size_of() const { return sizeof(*this); }
 475 protected:
 476   virtual uint cmp( const Node &n ) const;
 477   virtual bool depends_only_on_test() const { return false; }
 478 
 479   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 480   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 481 
 482 public:
 483   // We must ensure that stores of object references will be visible
 484   // only after the object's initialization. So the callers of this
 485   // procedure must indicate that the store requires `release'
 486   // semantics, if the stored value is an object reference that might
 487   // point to a new object and may become externally visible.
 488   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 489     : MemNode(c, mem, adr, at, val), _mo(mo) {
 490     init_class_id(Class_Store);
 491   }
 492   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 493     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 494     init_class_id(Class_Store);
 495   }
 496 
 497   inline bool is_unordered() const { return !is_release(); }
 498   inline bool is_release() const {
 499     assert((_mo == unordered || _mo == release), "unexpected");
 500     return _mo == release;
 501   }
 502 
 503   // Conservatively release stores of object references in order to
 504   // ensure visibility of object initialization.
 505   static inline MemOrd release_if_reference(const BasicType t) {
 506     const MemOrd mo = (t == T_ARRAY ||
 507                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 508                        t == T_OBJECT) ? release : unordered;
 509     return mo;
 510   }
 511 
 512   // Polymorphic factory method
 513   //
 514   // We must ensure that stores of object references will be visible
 515   // only after the object's initialization. So the callers of this
 516   // procedure must indicate that the store requires `release'
 517   // semantics, if the stored value is an object reference that might
 518   // point to a new object and may become externally visible.
 519   static StoreNode* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 520                          const TypePtr* at, Node *val, BasicType bt, MemOrd mo);
 521 
 522   virtual uint hash() const;    // Check the type
 523 
 524   // If the store is to Field memory and the pointer is non-null, we can
 525   // zero out the control input.
 526   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 527 
 528   // Compute a new Type for this node.  Basically we just do the pre-check,
 529   // then call the virtual add() to set the type.
 530   virtual const Type *Value( PhaseTransform *phase ) const;
 531 
 532   // Check for identity function on memory (Load then Store at same address)
 533   virtual Node *Identity( PhaseTransform *phase );
 534 
 535   // Do not match memory edge
 536   virtual uint match_edge(uint idx) const;
 537 
 538   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 539 
 540   // Map a store opcode to its corresponding own opcode, trivially.
 541   virtual int store_Opcode() const { return Opcode(); }
 542 
 543   // have all possible loads of the value stored been optimized away?
 544   bool value_never_loaded(PhaseTransform *phase) const;
 545 };
 546 
 547 //------------------------------StoreBNode-------------------------------------
 548 // Store byte to memory
 549 class StoreBNode : public StoreNode {
 550 public:
 551   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 552     : StoreNode(c, mem, adr, at, val, mo) {}
 553   virtual int Opcode() const;
 554   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 555   virtual BasicType memory_type() const { return T_BYTE; }
 556 };
 557 
 558 //------------------------------StoreCNode-------------------------------------
 559 // Store char/short to memory
 560 class StoreCNode : public StoreNode {
 561 public:
 562   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 563     : StoreNode(c, mem, adr, at, val, mo) {}
 564   virtual int Opcode() const;
 565   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 566   virtual BasicType memory_type() const { return T_CHAR; }
 567 };
 568 
 569 //------------------------------StoreINode-------------------------------------
 570 // Store int to memory
 571 class StoreINode : public StoreNode {
 572 public:
 573   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 574     : StoreNode(c, mem, adr, at, val, mo) {}
 575   virtual int Opcode() const;
 576   virtual BasicType memory_type() const { return T_INT; }
 577 };
 578 
 579 //------------------------------StoreLNode-------------------------------------
 580 // Store long to memory
 581 class StoreLNode : public StoreNode {
 582   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 583   virtual uint cmp( const Node &n ) const {
 584     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 585       && StoreNode::cmp(n);
 586   }
 587   virtual uint size_of() const { return sizeof(*this); }
 588   const bool _require_atomic_access;  // is piecewise store forbidden?
 589 
 590 public:
 591   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 592     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 593   virtual int Opcode() const;
 594   virtual BasicType memory_type() const { return T_LONG; }
 595   bool require_atomic_access() { return _require_atomic_access; }
 596   static StoreLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 597 #ifndef PRODUCT
 598   virtual void dump_spec(outputStream *st) const {
 599     StoreNode::dump_spec(st);
 600     if (_require_atomic_access)  st->print(" Atomic!");
 601   }
 602 #endif
 603 };
 604 
 605 //------------------------------StoreFNode-------------------------------------
 606 // Store float to memory
 607 class StoreFNode : public StoreNode {
 608 public:
 609   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 610     : StoreNode(c, mem, adr, at, val, mo) {}
 611   virtual int Opcode() const;
 612   virtual BasicType memory_type() const { return T_FLOAT; }
 613 };
 614 
 615 //------------------------------StoreDNode-------------------------------------
 616 // Store double to memory
 617 class StoreDNode : public StoreNode {
 618   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 619   virtual uint cmp( const Node &n ) const {
 620     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 621       && StoreNode::cmp(n);
 622   }
 623   virtual uint size_of() const { return sizeof(*this); }
 624   const bool _require_atomic_access;  // is piecewise store forbidden?
 625 public:
 626   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 627              MemOrd mo, bool require_atomic_access = false)
 628     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 629   virtual int Opcode() const;
 630   virtual BasicType memory_type() const { return T_DOUBLE; }
 631   bool require_atomic_access() { return _require_atomic_access; }
 632   static StoreDNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, MemOrd mo);
 633 #ifndef PRODUCT
 634   virtual void dump_spec(outputStream *st) const {
 635     StoreNode::dump_spec(st);
 636     if (_require_atomic_access)  st->print(" Atomic!");
 637   }
 638 #endif
 639 
 640 };
 641 
 642 //------------------------------StorePNode-------------------------------------
 643 // Store pointer to memory
 644 class StorePNode : public StoreNode {
 645 public:
 646   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 647     : StoreNode(c, mem, adr, at, val, mo) {}
 648   virtual int Opcode() const;
 649   virtual BasicType memory_type() const { return T_ADDRESS; }
 650 };
 651 
 652 //------------------------------StoreNNode-------------------------------------
 653 // Store narrow oop to memory
 654 class StoreNNode : public StoreNode {
 655 public:
 656   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 657     : StoreNode(c, mem, adr, at, val, mo) {}
 658   virtual int Opcode() const;
 659   virtual BasicType memory_type() const { return T_NARROWOOP; }
 660 };
 661 
 662 //------------------------------StoreNKlassNode--------------------------------------
 663 // Store narrow klass to memory
 664 class StoreNKlassNode : public StoreNNode {
 665 public:
 666   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 667     : StoreNNode(c, mem, adr, at, val, mo) {}
 668   virtual int Opcode() const;
 669   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 670 };
 671 
 672 //------------------------------StoreCMNode-----------------------------------
 673 // Store card-mark byte to memory for CM
 674 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store
 675 // Preceeding equivalent StoreCMs may be eliminated.
 676 class StoreCMNode : public StoreNode {
 677  private:
 678   virtual uint hash() const { return StoreNode::hash() + _oop_alias_idx; }
 679   virtual uint cmp( const Node &n ) const {
 680     return _oop_alias_idx == ((StoreCMNode&)n)._oop_alias_idx
 681       && StoreNode::cmp(n);
 682   }
 683   virtual uint size_of() const { return sizeof(*this); }
 684   int _oop_alias_idx;   // The alias_idx of OopStore
 685 
 686 public:
 687   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, int oop_alias_idx ) :
 688     StoreNode(c, mem, adr, at, val, oop_store, MemNode::release),
 689     _oop_alias_idx(oop_alias_idx) {
 690     assert(_oop_alias_idx >= Compile::AliasIdxRaw ||
 691            _oop_alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
 692            "bad oop alias idx");
 693   }
 694   virtual int Opcode() const;
 695   virtual Node *Identity( PhaseTransform *phase );
 696   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 697   virtual const Type *Value( PhaseTransform *phase ) const;
 698   virtual BasicType memory_type() const { return T_VOID; } // unspecific
 699   int oop_alias_idx() const { return _oop_alias_idx; }
 700 };
 701 
 702 //------------------------------LoadPLockedNode---------------------------------
 703 // Load-locked a pointer from memory (either object or array).
 704 // On Sparc & Intel this is implemented as a normal pointer load.
 705 // On PowerPC and friends it's a real load-locked.
 706 class LoadPLockedNode : public LoadPNode {
 707 public:
 708   LoadPLockedNode(Node *c, Node *mem, Node *adr, MemOrd mo)
 709     : LoadPNode(c, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM, mo) {}
 710   virtual int Opcode() const;
 711   virtual int store_Opcode() const { return Op_StorePConditional; }
 712   virtual bool depends_only_on_test() const { return true; }
 713 };
 714 
 715 //------------------------------SCMemProjNode---------------------------------------
 716 // This class defines a projection of the memory  state of a store conditional node.
 717 // These nodes return a value, but also update memory.
 718 class SCMemProjNode : public ProjNode {
 719 public:
 720   enum {SCMEMPROJCON = (uint)-2};
 721   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 722   virtual int Opcode() const;
 723   virtual bool      is_CFG() const  { return false; }
 724   virtual const Type *bottom_type() const {return Type::MEMORY;}
 725   virtual const TypePtr *adr_type() const { return in(0)->in(MemNode::Memory)->adr_type();}
 726   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 727   virtual const Type *Value( PhaseTransform *phase ) const;
 728 #ifndef PRODUCT
 729   virtual void dump_spec(outputStream *st) const {};
 730 #endif
 731 };
 732 
 733 //------------------------------LoadStoreNode---------------------------
 734 // Note: is_Mem() method returns 'true' for this class.
 735 class LoadStoreNode : public Node {
 736 private:
 737   const Type* const _type;      // What kind of value is loaded?
 738   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 739   virtual uint size_of() const; // Size is bigger
 740 public:
 741   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 742   virtual bool depends_only_on_test() const { return false; }
 743   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 744 
 745   virtual const Type *bottom_type() const { return _type; }
 746   virtual uint ideal_reg() const;
 747   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 748 
 749   bool result_not_used() const;
 750 };
 751 
 752 class LoadStoreConditionalNode : public LoadStoreNode {
 753 public:
 754   enum {
 755     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 756   };
 757   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 758 };
 759 
 760 //------------------------------StorePConditionalNode---------------------------
 761 // Conditionally store pointer to memory, if no change since prior
 762 // load-locked.  Sets flags for success or failure of the store.
 763 class StorePConditionalNode : public LoadStoreConditionalNode {
 764 public:
 765   StorePConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 766   virtual int Opcode() const;
 767   // Produces flags
 768   virtual uint ideal_reg() const { return Op_RegFlags; }
 769 };
 770 
 771 //------------------------------StoreIConditionalNode---------------------------
 772 // Conditionally store int to memory, if no change since prior
 773 // load-locked.  Sets flags for success or failure of the store.
 774 class StoreIConditionalNode : public LoadStoreConditionalNode {
 775 public:
 776   StoreIConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ii ) : LoadStoreConditionalNode(c, mem, adr, val, ii) { }
 777   virtual int Opcode() const;
 778   // Produces flags
 779   virtual uint ideal_reg() const { return Op_RegFlags; }
 780 };
 781 
 782 //------------------------------StoreLConditionalNode---------------------------
 783 // Conditionally store long to memory, if no change since prior
 784 // load-locked.  Sets flags for success or failure of the store.
 785 class StoreLConditionalNode : public LoadStoreConditionalNode {
 786 public:
 787   StoreLConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 788   virtual int Opcode() const;
 789   // Produces flags
 790   virtual uint ideal_reg() const { return Op_RegFlags; }
 791 };
 792 
 793 
 794 //------------------------------CompareAndSwapLNode---------------------------
 795 class CompareAndSwapLNode : public LoadStoreConditionalNode {
 796 public:
 797   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 798   virtual int Opcode() const;
 799 };
 800 
 801 
 802 //------------------------------CompareAndSwapINode---------------------------
 803 class CompareAndSwapINode : public LoadStoreConditionalNode {
 804 public:
 805   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 806   virtual int Opcode() const;
 807 };
 808 
 809 
 810 //------------------------------CompareAndSwapPNode---------------------------
 811 class CompareAndSwapPNode : public LoadStoreConditionalNode {
 812 public:
 813   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 814   virtual int Opcode() const;
 815 };
 816 
 817 //------------------------------CompareAndSwapNNode---------------------------
 818 class CompareAndSwapNNode : public LoadStoreConditionalNode {
 819 public:
 820   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 821   virtual int Opcode() const;
 822 };
 823 
 824 //------------------------------GetAndAddINode---------------------------
 825 class GetAndAddINode : public LoadStoreNode {
 826 public:
 827   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
 828   virtual int Opcode() const;
 829 };
 830 
 831 //------------------------------GetAndAddLNode---------------------------
 832 class GetAndAddLNode : public LoadStoreNode {
 833 public:
 834   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
 835   virtual int Opcode() const;
 836 };
 837 
 838 
 839 //------------------------------GetAndSetINode---------------------------
 840 class GetAndSetINode : public LoadStoreNode {
 841 public:
 842   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
 843   virtual int Opcode() const;
 844 };
 845 
 846 //------------------------------GetAndSetINode---------------------------
 847 class GetAndSetLNode : public LoadStoreNode {
 848 public:
 849   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
 850   virtual int Opcode() const;
 851 };
 852 
 853 //------------------------------GetAndSetPNode---------------------------
 854 class GetAndSetPNode : public LoadStoreNode {
 855 public:
 856   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
 857   virtual int Opcode() const;
 858 };
 859 
 860 //------------------------------GetAndSetNNode---------------------------
 861 class GetAndSetNNode : public LoadStoreNode {
 862 public:
 863   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
 864   virtual int Opcode() const;
 865 };
 866 
 867 //------------------------------ClearArray-------------------------------------
 868 class ClearArrayNode: public Node {
 869 public:
 870   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base )
 871     : Node(ctrl,arymem,word_cnt,base) {
 872     init_class_id(Class_ClearArray);
 873   }
 874   virtual int         Opcode() const;
 875   virtual const Type *bottom_type() const { return Type::MEMORY; }
 876   // ClearArray modifies array elements, and so affects only the
 877   // array memory addressed by the bottom_type of its base address.
 878   virtual const class TypePtr *adr_type() const;
 879   virtual Node *Identity( PhaseTransform *phase );
 880   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 881   virtual uint match_edge(uint idx) const;
 882 
 883   // Clear the given area of an object or array.
 884   // The start offset must always be aligned mod BytesPerInt.
 885   // The end offset must always be aligned mod BytesPerLong.
 886   // Return the new memory.
 887   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 888                             intptr_t start_offset,
 889                             intptr_t end_offset,
 890                             PhaseGVN* phase);
 891   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 892                             intptr_t start_offset,
 893                             Node* end_offset,
 894                             PhaseGVN* phase);
 895   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 896                             Node* start_offset,
 897                             Node* end_offset,
 898                             PhaseGVN* phase);
 899   // Return allocation input memory edge if it is different instance
 900   // or itself if it is the one we are looking for.
 901   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
 902 };
 903 
 904 //------------------------------MemBar-----------------------------------------
 905 // There are different flavors of Memory Barriers to match the Java Memory
 906 // Model.  Monitor-enter and volatile-load act as Aquires: no following ref
 907 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
 908 // volatile-load.  Monitor-exit and volatile-store act as Release: no
 909 // preceding ref can be moved to after them.  We insert a MemBar-Release
 910 // before a FastUnlock or volatile-store.  All volatiles need to be
 911 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
 912 // separate it from any following volatile-load.
 913 class MemBarNode: public MultiNode {
 914   virtual uint hash() const ;                  // { return NO_HASH; }
 915   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
 916 
 917   virtual uint size_of() const { return sizeof(*this); }
 918   // Memory type this node is serializing.  Usually either rawptr or bottom.
 919   const TypePtr* _adr_type;
 920 
 921 public:
 922   enum {
 923     Precedent = TypeFunc::Parms  // optional edge to force precedence
 924   };
 925   MemBarNode(Compile* C, int alias_idx, Node* precedent);
 926   virtual int Opcode() const = 0;
 927   virtual const class TypePtr *adr_type() const { return _adr_type; }
 928   virtual const Type *Value( PhaseTransform *phase ) const;
 929   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 930   virtual uint match_edge(uint idx) const { return 0; }
 931   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
 932   virtual Node *match( const ProjNode *proj, const Matcher *m );
 933   // Factory method.  Builds a wide or narrow membar.
 934   // Optional 'precedent' becomes an extra edge if not null.
 935   static MemBarNode* make(Compile* C, int opcode,
 936                           int alias_idx = Compile::AliasIdxBot,
 937                           Node* precedent = NULL);
 938 };
 939 
 940 // "Acquire" - no following ref can move before (but earlier refs can
 941 // follow, like an early Load stalled in cache).  Requires multi-cpu
 942 // visibility.  Inserted after a volatile load.
 943 class MemBarAcquireNode: public MemBarNode {
 944 public:
 945   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
 946     : MemBarNode(C, alias_idx, precedent) {}
 947   virtual int Opcode() const;
 948 };
 949 
 950 // "Acquire" - no following ref can move before (but earlier refs can
 951 // follow, like an early Load stalled in cache).  Requires multi-cpu
 952 // visibility.  Inserted independ of any load, as required
 953 // for intrinsic sun.misc.Unsafe.loadFence().
 954 class LoadFenceNode: public MemBarNode {
 955 public:
 956   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
 957     : MemBarNode(C, alias_idx, precedent) {}
 958   virtual int Opcode() const;
 959 };
 960 
 961 // "Release" - no earlier ref can move after (but later refs can move
 962 // up, like a speculative pipelined cache-hitting Load).  Requires
 963 // multi-cpu visibility.  Inserted before a volatile store.
 964 class MemBarReleaseNode: public MemBarNode {
 965 public:
 966   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
 967     : MemBarNode(C, alias_idx, precedent) {}
 968   virtual int Opcode() const;
 969 };
 970 
 971 // "Release" - no earlier ref can move after (but later refs can move
 972 // up, like a speculative pipelined cache-hitting Load).  Requires
 973 // multi-cpu visibility.  Inserted independent of any store, as required
 974 // for intrinsic sun.misc.Unsafe.storeFence().
 975 class StoreFenceNode: public MemBarNode {
 976 public:
 977   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
 978     : MemBarNode(C, alias_idx, precedent) {}
 979   virtual int Opcode() const;
 980 };
 981 
 982 // "Acquire" - no following ref can move before (but earlier refs can
 983 // follow, like an early Load stalled in cache).  Requires multi-cpu
 984 // visibility.  Inserted after a FastLock.
 985 class MemBarAcquireLockNode: public MemBarNode {
 986 public:
 987   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
 988     : MemBarNode(C, alias_idx, precedent) {}
 989   virtual int Opcode() const;
 990 };
 991 
 992 // "Release" - no earlier ref can move after (but later refs can move
 993 // up, like a speculative pipelined cache-hitting Load).  Requires
 994 // multi-cpu visibility.  Inserted before a FastUnLock.
 995 class MemBarReleaseLockNode: public MemBarNode {
 996 public:
 997   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
 998     : MemBarNode(C, alias_idx, precedent) {}
 999   virtual int Opcode() const;
1000 };
1001 
1002 class MemBarStoreStoreNode: public MemBarNode {
1003 public:
1004   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1005     : MemBarNode(C, alias_idx, precedent) {
1006     init_class_id(Class_MemBarStoreStore);
1007   }
1008   virtual int Opcode() const;
1009 };
1010 
1011 // Ordering between a volatile store and a following volatile load.
1012 // Requires multi-CPU visibility?
1013 class MemBarVolatileNode: public MemBarNode {
1014 public:
1015   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1016     : MemBarNode(C, alias_idx, precedent) {}
1017   virtual int Opcode() const;
1018 };
1019 
1020 // Ordering within the same CPU.  Used to order unsafe memory references
1021 // inside the compiler when we lack alias info.  Not needed "outside" the
1022 // compiler because the CPU does all the ordering for us.
1023 class MemBarCPUOrderNode: public MemBarNode {
1024 public:
1025   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1026     : MemBarNode(C, alias_idx, precedent) {}
1027   virtual int Opcode() const;
1028   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1029 };
1030 
1031 // Isolation of object setup after an AllocateNode and before next safepoint.
1032 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1033 class InitializeNode: public MemBarNode {
1034   friend class AllocateNode;
1035 
1036   enum {
1037     Incomplete    = 0,
1038     Complete      = 1,
1039     WithArraycopy = 2
1040   };
1041   int _is_complete;
1042 
1043   bool _does_not_escape;
1044 
1045 public:
1046   enum {
1047     Control    = TypeFunc::Control,
1048     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1049     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1050     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1051   };
1052 
1053   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1054   virtual int Opcode() const;
1055   virtual uint size_of() const { return sizeof(*this); }
1056   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1057   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1058 
1059   // Manage incoming memory edges via a MergeMem on in(Memory):
1060   Node* memory(uint alias_idx);
1061 
1062   // The raw memory edge coming directly from the Allocation.
1063   // The contents of this memory are *always* all-zero-bits.
1064   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1065 
1066   // Return the corresponding allocation for this initialization (or null if none).
1067   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1068   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1069   AllocateNode* allocation();
1070 
1071   // Anything other than zeroing in this init?
1072   bool is_non_zero();
1073 
1074   // An InitializeNode must completed before macro expansion is done.
1075   // Completion requires that the AllocateNode must be followed by
1076   // initialization of the new memory to zero, then to any initializers.
1077   bool is_complete() { return _is_complete != Incomplete; }
1078   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1079 
1080   // Mark complete.  (Must not yet be complete.)
1081   void set_complete(PhaseGVN* phase);
1082   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1083 
1084   bool does_not_escape() { return _does_not_escape; }
1085   void set_does_not_escape() { _does_not_escape = true; }
1086 
1087 #ifdef ASSERT
1088   // ensure all non-degenerate stores are ordered and non-overlapping
1089   bool stores_are_sane(PhaseTransform* phase);
1090 #endif //ASSERT
1091 
1092   // See if this store can be captured; return offset where it initializes.
1093   // Return 0 if the store cannot be moved (any sort of problem).
1094   intptr_t can_capture_store(StoreNode* st, PhaseTransform* phase, bool can_reshape);
1095 
1096   // Capture another store; reformat it to write my internal raw memory.
1097   // Return the captured copy, else NULL if there is some sort of problem.
1098   Node* capture_store(StoreNode* st, intptr_t start, PhaseTransform* phase, bool can_reshape);
1099 
1100   // Find captured store which corresponds to the range [start..start+size).
1101   // Return my own memory projection (meaning the initial zero bits)
1102   // if there is no such store.  Return NULL if there is a problem.
1103   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);
1104 
1105   // Called when the associated AllocateNode is expanded into CFG.
1106   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1107                         intptr_t header_size, Node* size_in_bytes,
1108                         PhaseGVN* phase);
1109 
1110  private:
1111   void remove_extra_zeroes();
1112 
1113   // Find out where a captured store should be placed (or already is placed).
1114   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1115                                      PhaseTransform* phase);
1116 
1117   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);
1118 
1119   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);
1120 
1121   bool detect_init_independence(Node* n, int& count);
1122 
1123   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1124                                PhaseGVN* phase);
1125 
1126   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1127 };
1128 
1129 //------------------------------MergeMem---------------------------------------
1130 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1131 class MergeMemNode: public Node {
1132   virtual uint hash() const ;                  // { return NO_HASH; }
1133   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
1134   friend class MergeMemStream;
1135   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1136 
1137 public:
1138   // If the input is a whole memory state, clone it with all its slices intact.
1139   // Otherwise, make a new memory state with just that base memory input.
1140   // In either case, the result is a newly created MergeMem.
1141   static MergeMemNode* make(Compile* C, Node* base_memory);
1142 
1143   virtual int Opcode() const;
1144   virtual Node *Identity( PhaseTransform *phase );
1145   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1146   virtual uint ideal_reg() const { return NotAMachineReg; }
1147   virtual uint match_edge(uint idx) const { return 0; }
1148   virtual const RegMask &out_RegMask() const;
1149   virtual const Type *bottom_type() const { return Type::MEMORY; }
1150   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1151   // sparse accessors
1152   // Fetch the previously stored "set_memory_at", or else the base memory.
1153   // (Caller should clone it if it is a phi-nest.)
1154   Node* memory_at(uint alias_idx) const;
1155   // set the memory, regardless of its previous value
1156   void set_memory_at(uint alias_idx, Node* n);
1157   // the "base" is the memory that provides the non-finite support
1158   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1159   // warning: setting the base can implicitly set any of the other slices too
1160   void set_base_memory(Node* def);
1161   // sentinel value which denotes a copy of the base memory:
1162   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1163   static Node* make_empty_memory(); // where the sentinel comes from
1164   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1165   // hook for the iterator, to perform any necessary setup
1166   void iteration_setup(const MergeMemNode* other = NULL);
1167   // push sentinels until I am at least as long as the other (semantic no-op)
1168   void grow_to_match(const MergeMemNode* other);
1169   bool verify_sparse() const PRODUCT_RETURN0;
1170 #ifndef PRODUCT
1171   virtual void dump_spec(outputStream *st) const;
1172 #endif
1173 };
1174 
1175 class MergeMemStream : public StackObj {
1176  private:
1177   MergeMemNode*       _mm;
1178   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1179   Node*               _mm_base;  // loop-invariant base memory of _mm
1180   int                 _idx;
1181   int                 _cnt;
1182   Node*               _mem;
1183   Node*               _mem2;
1184   int                 _cnt2;
1185 
1186   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {
1187     // subsume_node will break sparseness at times, whenever a memory slice
1188     // folds down to a copy of the base ("fat") memory.  In such a case,
1189     // the raw edge will update to base, although it should be top.
1190     // This iterator will recognize either top or base_memory as an
1191     // "empty" slice.  See is_empty, is_empty2, and next below.
1192     //
1193     // The sparseness property is repaired in MergeMemNode::Ideal.
1194     // As long as access to a MergeMem goes through this iterator
1195     // or the memory_at accessor, flaws in the sparseness will
1196     // never be observed.
1197     //
1198     // Also, iteration_setup repairs sparseness.
1199     assert(mm->verify_sparse(), "please, no dups of base");
1200     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");
1201 
1202     _mm  = mm;
1203     _mm_base = mm->base_memory();
1204     _mm2 = mm2;
1205     _cnt = mm->req();
1206     _idx = Compile::AliasIdxBot-1; // start at the base memory
1207     _mem = NULL;
1208     _mem2 = NULL;
1209   }
1210 
1211 #ifdef ASSERT
1212   Node* check_memory() const {
1213     if (at_base_memory())
1214       return _mm->base_memory();
1215     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1216       return _mm->memory_at(_idx);
1217     else
1218       return _mm_base;
1219   }
1220   Node* check_memory2() const {
1221     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1222   }
1223 #endif
1224 
1225   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1226   void assert_synch() const {
1227     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1228            "no side-effects except through the stream");
1229   }
1230 
1231  public:
1232 
1233   // expected usages:
1234   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1235   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1236 
1237   // iterate over one merge
1238   MergeMemStream(MergeMemNode* mm) {
1239     mm->iteration_setup();
1240     init(mm);
1241     debug_only(_cnt2 = 999);
1242   }
1243   // iterate in parallel over two merges
1244   // only iterates through non-empty elements of mm2
1245   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1246     assert(mm2, "second argument must be a MergeMem also");
1247     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1248     mm->iteration_setup(mm2);
1249     init(mm, mm2);
1250     _cnt2 = mm2->req();
1251   }
1252 #ifdef ASSERT
1253   ~MergeMemStream() {
1254     assert_synch();
1255   }
1256 #endif
1257 
1258   MergeMemNode* all_memory() const {
1259     return _mm;
1260   }
1261   Node* base_memory() const {
1262     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1263     return _mm_base;
1264   }
1265   const MergeMemNode* all_memory2() const {
1266     assert(_mm2 != NULL, "");
1267     return _mm2;
1268   }
1269   bool at_base_memory() const {
1270     return _idx == Compile::AliasIdxBot;
1271   }
1272   int alias_idx() const {
1273     assert(_mem, "must call next 1st");
1274     return _idx;
1275   }
1276 
1277   const TypePtr* adr_type() const {
1278     return Compile::current()->get_adr_type(alias_idx());
1279   }
1280 
1281   const TypePtr* adr_type(Compile* C) const {
1282     return C->get_adr_type(alias_idx());
1283   }
1284   bool is_empty() const {
1285     assert(_mem, "must call next 1st");
1286     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1287     return _mem->is_top();
1288   }
1289   bool is_empty2() const {
1290     assert(_mem2, "must call next 1st");
1291     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1292     return _mem2->is_top();
1293   }
1294   Node* memory() const {
1295     assert(!is_empty(), "must not be empty");
1296     assert_synch();
1297     return _mem;
1298   }
1299   // get the current memory, regardless of empty or non-empty status
1300   Node* force_memory() const {
1301     assert(!is_empty() || !at_base_memory(), "");
1302     // Use _mm_base to defend against updates to _mem->base_memory().
1303     Node *mem = _mem->is_top() ? _mm_base : _mem;
1304     assert(mem == check_memory(), "");
1305     return mem;
1306   }
1307   Node* memory2() const {
1308     assert(_mem2 == check_memory2(), "");
1309     return _mem2;
1310   }
1311   void set_memory(Node* mem) {
1312     if (at_base_memory()) {
1313       // Note that this does not change the invariant _mm_base.
1314       _mm->set_base_memory(mem);
1315     } else {
1316       _mm->set_memory_at(_idx, mem);
1317     }
1318     _mem = mem;
1319     assert_synch();
1320   }
1321 
1322   // Recover from a side effect to the MergeMemNode.
1323   void set_memory() {
1324     _mem = _mm->in(_idx);
1325   }
1326 
1327   bool next()  { return next(false); }
1328   bool next2() { return next(true); }
1329 
1330   bool next_non_empty()  { return next_non_empty(false); }
1331   bool next_non_empty2() { return next_non_empty(true); }
1332   // next_non_empty2 can yield states where is_empty() is true
1333 
1334  private:
1335   // find the next item, which might be empty
1336   bool next(bool have_mm2) {
1337     assert((_mm2 != NULL) == have_mm2, "use other next");
1338     assert_synch();
1339     if (++_idx < _cnt) {
1340       // Note:  This iterator allows _mm to be non-sparse.
1341       // It behaves the same whether _mem is top or base_memory.
1342       _mem = _mm->in(_idx);
1343       if (have_mm2)
1344         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1345       return true;
1346     }
1347     return false;
1348   }
1349 
1350   // find the next non-empty item
1351   bool next_non_empty(bool have_mm2) {
1352     while (next(have_mm2)) {
1353       if (!is_empty()) {
1354         // make sure _mem2 is filled in sensibly
1355         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1356         return true;
1357       } else if (have_mm2 && !is_empty2()) {
1358         return true;   // is_empty() == true
1359       }
1360     }
1361     return false;
1362   }
1363 };
1364 
1365 //------------------------------Prefetch---------------------------------------
1366 
1367 // Non-faulting prefetch load.  Prefetch for many reads.
1368 class PrefetchReadNode : public Node {
1369 public:
1370   PrefetchReadNode(Node *abio, Node *adr) : Node(0,abio,adr) {}
1371   virtual int Opcode() const;
1372   virtual uint ideal_reg() const { return NotAMachineReg; }
1373   virtual uint match_edge(uint idx) const { return idx==2; }
1374   virtual const Type *bottom_type() const { return Type::ABIO; }
1375 };
1376 
1377 // Non-faulting prefetch load.  Prefetch for many reads & many writes.
1378 class PrefetchWriteNode : public Node {
1379 public:
1380   PrefetchWriteNode(Node *abio, Node *adr) : Node(0,abio,adr) {}
1381   virtual int Opcode() const;
1382   virtual uint ideal_reg() const { return NotAMachineReg; }
1383   virtual uint match_edge(uint idx) const { return idx==2; }
1384   virtual const Type *bottom_type() const { return Type::ABIO; }
1385 };
1386 
1387 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1388 class PrefetchAllocationNode : public Node {
1389 public:
1390   PrefetchAllocationNode(Node *mem, Node *adr) : Node(0,mem,adr) {}
1391   virtual int Opcode() const;
1392   virtual uint ideal_reg() const { return NotAMachineReg; }
1393   virtual uint match_edge(uint idx) const { return idx==2; }
1394   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1395 };
1396 
1397 #endif // SHARE_VM_OPTO_MEMNODE_HPP