1 /*
   2  * Copyright (c) 1997, 2012, 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 protected:
  55   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at )
  56     : Node(c0,c1,c2   ) {
  57     init_class_id(Class_Mem);
  58     debug_only(_adr_type=at; adr_type();)
  59   }
  60   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 )
  61     : Node(c0,c1,c2,c3) {
  62     init_class_id(Class_Mem);
  63     debug_only(_adr_type=at; adr_type();)
  64   }
  65   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4)
  66     : Node(c0,c1,c2,c3,c4) {
  67     init_class_id(Class_Mem);
  68     debug_only(_adr_type=at; adr_type();)
  69   }
  70 
  71 public:
  72   // Helpers for the optimizer.  Documented in memnode.cpp.
  73   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
  74                                       Node* p2, AllocateNode* a2,
  75                                       PhaseTransform* phase);
  76   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
  77 
  78   static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
  79   static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
  80   // This one should probably be a phase-specific function:
  81   static bool all_controls_dominate(Node* dom, Node* sub);
  82 
  83   // Find any cast-away of null-ness and keep its control.
  84   static  Node *Ideal_common_DU_postCCP( PhaseCCP *ccp, Node* n, Node* adr );
  85   virtual Node *Ideal_DU_postCCP( PhaseCCP *ccp );
  86 
  87   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
  88 
  89   // Shared code for Ideal methods:
  90   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.
  91 
  92   // Helper function for adr_type() implementations.
  93   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);
  94 
  95   // Raw access function, to allow copying of adr_type efficiently in
  96   // product builds and retain the debug info for debug builds.
  97   const TypePtr *raw_adr_type() const {
  98 #ifdef ASSERT
  99     return _adr_type;
 100 #else
 101     return 0;
 102 #endif
 103   }
 104 
 105   // Map a load or store opcode to its corresponding store opcode.
 106   // (Return -1 if unknown.)
 107   virtual int store_Opcode() const { return -1; }
 108 
 109   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 110   virtual BasicType memory_type() const = 0;
 111   virtual int memory_size() const {
 112 #ifdef ASSERT
 113     return type2aelembytes(memory_type(), true);
 114 #else
 115     return type2aelembytes(memory_type());
 116 #endif
 117   }
 118 
 119   // Search through memory states which precede this node (load or store).
 120   // Look for an exact match for the address, with no intervening
 121   // aliased stores.
 122   Node* find_previous_store(PhaseTransform* phase);
 123 
 124   // Can this node (load or store) accurately see a stored value in
 125   // the given memory state?  (The state may or may not be in(Memory).)
 126   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;
 127 
 128 #ifndef PRODUCT
 129   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 130   virtual void dump_spec(outputStream *st) const;
 131 #endif
 132 };
 133 
 134 //------------------------------LoadNode---------------------------------------
 135 // Load value; requires Memory and Address
 136 class LoadNode : public MemNode {
 137 public:
 138   typedef enum { unordered = 0, acquire } Sem;
 139 
 140 private:
 141   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 142   // loads that can be reordered, and such requiring acquire semantics to
 143   // adhere to the Java specification.  The required behaviour is stored in
 144   // this field.
 145   const Sem _sem;
 146 
 147 protected:
 148   virtual uint cmp(const Node &n) const;
 149   virtual uint size_of() const; // Size is bigger
 150   const Type* const _type;      // What kind of value is loaded?
 151 public:
 152 
 153   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, Sem sem)
 154     : MemNode(c,mem,adr,at), _type(rt), _sem(sem) {
 155     init_class_id(Class_Load);
 156   }
 157   inline bool is_unordered() const { return !is_acquire(); }
 158   inline bool is_acquire() const {
 159     assert(_sem == unordered || _sem == acquire, "unexpected");
 160     return _sem == acquire;
 161   }
 162 
 163   // Polymorphic factory method:
 164    static Node* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 165                      const TypePtr* at, const Type *rt, BasicType bt, Sem sem);
 166 
 167   virtual uint hash()   const;  // Check the type
 168 
 169   // Handle algebraic identities here.  If we have an identity, return the Node
 170   // we are equivalent to.  We look for Load of a Store.
 171   virtual Node *Identity( PhaseTransform *phase );
 172 
 173   // If the load is from Field memory and the pointer is non-null, we can
 174   // zero out the control input.
 175   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 176 
 177   // Split instance field load through Phi.
 178   Node* split_through_phi(PhaseGVN *phase);
 179 
 180   // Recover original value from boxed values
 181   Node *eliminate_autobox(PhaseGVN *phase);
 182 
 183   // Compute a new Type for this node.  Basically we just do the pre-check,
 184   // then call the virtual add() to set the type.
 185   virtual const Type *Value( PhaseTransform *phase ) const;
 186 
 187   // Common methods for LoadKlass and LoadNKlass nodes.
 188   const Type *klass_value_common( PhaseTransform *phase ) const;
 189   Node *klass_identity_common( PhaseTransform *phase );
 190 
 191   virtual uint ideal_reg() const;
 192   virtual const Type *bottom_type() const;
 193   // Following method is copied from TypeNode:
 194   void set_type(const Type* t) {
 195     assert(t != NULL, "sanity");
 196     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 197     *(const Type**)&_type = t;   // cast away const-ness
 198     // If this node is in the hash table, make sure it doesn't need a rehash.
 199     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 200   }
 201   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
 202 
 203   // Do not match memory edge
 204   virtual uint match_edge(uint idx) const;
 205 
 206   // Map a load opcode to its corresponding store opcode.
 207   virtual int store_Opcode() const = 0;
 208 
 209   // Check if the load's memory input is a Phi node with the same control.
 210   bool is_instance_field_load_with_local_phi(Node* ctrl);
 211 
 212 #ifndef PRODUCT
 213   virtual void dump_spec(outputStream *st) const;
 214 #endif
 215 #ifdef ASSERT
 216   // Helper function to allow a raw load without control edge for some cases
 217   static bool is_immutable_value(Node* adr);
 218 #endif
 219 protected:
 220   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 221                                      ciKlass* klass) const;
 222 };
 223 
 224 //------------------------------LoadBNode--------------------------------------
 225 // Load a byte (8bits signed) from memory
 226 class LoadBNode : public LoadNode {
 227 public:
 228   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, Sem sem)
 229     : LoadNode(c, mem, adr, at, ti, sem) {}
 230   virtual int Opcode() const;
 231   virtual uint ideal_reg() const { return Op_RegI; }
 232   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 233   virtual const Type *Value(PhaseTransform *phase) const;
 234   virtual int store_Opcode() const { return Op_StoreB; }
 235   virtual BasicType memory_type() const { return T_BYTE; }
 236 };
 237 
 238 //------------------------------LoadUBNode-------------------------------------
 239 // Load a unsigned byte (8bits unsigned) from memory
 240 class LoadUBNode : public LoadNode {
 241 public:
 242   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, Sem sem)
 243     : LoadNode(c, mem, adr, at, ti, sem) {}
 244   virtual int Opcode() const;
 245   virtual uint ideal_reg() const { return Op_RegI; }
 246   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 247   virtual const Type *Value(PhaseTransform *phase) const;
 248   virtual int store_Opcode() const { return Op_StoreB; }
 249   virtual BasicType memory_type() const { return T_BYTE; }
 250 };
 251 
 252 //------------------------------LoadUSNode-------------------------------------
 253 // Load an unsigned short/char (16bits unsigned) from memory
 254 class LoadUSNode : public LoadNode {
 255 public:
 256   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, Sem sem)
 257     : LoadNode(c, mem, adr, at, ti, sem) {}
 258   virtual int Opcode() const;
 259   virtual uint ideal_reg() const { return Op_RegI; }
 260   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 261   virtual const Type *Value(PhaseTransform *phase) const;
 262   virtual int store_Opcode() const { return Op_StoreC; }
 263   virtual BasicType memory_type() const { return T_CHAR; }
 264 };
 265 
 266 //------------------------------LoadSNode--------------------------------------
 267 // Load a short (16bits signed) from memory
 268 class LoadSNode : public LoadNode {
 269 public:
 270   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, Sem sem)
 271     : LoadNode(c, mem, adr, at, ti, sem) {}
 272   virtual int Opcode() const;
 273   virtual uint ideal_reg() const { return Op_RegI; }
 274   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 275   virtual const Type *Value(PhaseTransform *phase) const;
 276   virtual int store_Opcode() const { return Op_StoreC; }
 277   virtual BasicType memory_type() const { return T_SHORT; }
 278 };
 279 
 280 //------------------------------LoadINode--------------------------------------
 281 // Load an integer from memory
 282 class LoadINode : public LoadNode {
 283 public:
 284   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, Sem sem)
 285     : LoadNode(c, mem, adr, at, ti, sem) {}
 286   virtual int Opcode() const;
 287   virtual uint ideal_reg() const { return Op_RegI; }
 288   virtual int store_Opcode() const { return Op_StoreI; }
 289   virtual BasicType memory_type() const { return T_INT; }
 290 };
 291 
 292 //------------------------------LoadRangeNode----------------------------------
 293 // Load an array length from the array
 294 class LoadRangeNode : public LoadINode {
 295 public:
 296   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 297     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, LoadNode::unordered) {}
 298   virtual int Opcode() const;
 299   virtual const Type *Value( PhaseTransform *phase ) const;
 300   virtual Node *Identity( PhaseTransform *phase );
 301   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 302 };
 303 
 304 //------------------------------LoadLNode--------------------------------------
 305 // Load a long from memory
 306 class LoadLNode : public LoadNode {
 307   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 308   virtual uint cmp( const Node &n ) const {
 309     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 310       && LoadNode::cmp(n);
 311   }
 312   virtual uint size_of() const { return sizeof(*this); }
 313   const bool _require_atomic_access;  // is piecewise load forbidden?
 314 
 315 public:
 316   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 317             bool require_atomic_access, Sem sem)
 318     : LoadNode(c, mem, adr, at, tl, sem), _require_atomic_access(require_atomic_access) {}
 319   virtual int Opcode() const;
 320   virtual uint ideal_reg() const { return Op_RegL; }
 321   virtual int store_Opcode() const { return Op_StoreL; }
 322   virtual BasicType memory_type() const { return T_LONG; }
 323   bool require_atomic_access() { return _require_atomic_access; }
 324   static LoadLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type,
 325                                 const Type* rt, Sem sem);
 326 #ifndef PRODUCT
 327   virtual void dump_spec(outputStream *st) const {
 328     LoadNode::dump_spec(st);
 329     if (_require_atomic_access)  st->print(" Atomic!");
 330   }
 331 #endif
 332 };
 333 
 334 //------------------------------LoadL_unalignedNode----------------------------
 335 // Load a long from unaligned memory
 336 class LoadL_unalignedNode : public LoadLNode {
 337 public:
 338   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Sem sem)
 339     : LoadLNode(c, mem, adr, at, TypeLong::LONG, false, sem) {}
 340   virtual int Opcode() const;
 341 };
 342 
 343 //------------------------------LoadFNode--------------------------------------
 344 // Load a float (64 bits) from memory
 345 class LoadFNode : public LoadNode {
 346 public:
 347   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, Sem sem)
 348     : LoadNode(c, mem, adr, at, t, sem) {}
 349   virtual int Opcode() const;
 350   virtual uint ideal_reg() const { return Op_RegF; }
 351   virtual int store_Opcode() const { return Op_StoreF; }
 352   virtual BasicType memory_type() const { return T_FLOAT; }
 353 };
 354 
 355 //------------------------------LoadDNode--------------------------------------
 356 // Load a double (64 bits) from memory
 357 class LoadDNode : public LoadNode {
 358 public:
 359   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, Sem sem)
 360     : LoadNode(c, mem, adr, at, t, sem) {}
 361   virtual int Opcode() const;
 362   virtual uint ideal_reg() const { return Op_RegD; }
 363   virtual int store_Opcode() const { return Op_StoreD; }
 364   virtual BasicType memory_type() const { return T_DOUBLE; }
 365 };
 366 
 367 //------------------------------LoadD_unalignedNode----------------------------
 368 // Load a double from unaligned memory
 369 class LoadD_unalignedNode : public LoadDNode {
 370 public:
 371   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Sem sem)
 372     : LoadDNode(c, mem, adr, at, Type::DOUBLE, sem) {}
 373   virtual int Opcode() const;
 374 };
 375 
 376 //------------------------------LoadPNode--------------------------------------
 377 // Load a pointer from memory (either object or array)
 378 class LoadPNode : public LoadNode {
 379 public:
 380   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, Sem sem)
 381     : LoadNode(c, mem, adr, at, t, sem) {}
 382   virtual int Opcode() const;
 383   virtual uint ideal_reg() const { return Op_RegP; }
 384   virtual int store_Opcode() const { return Op_StoreP; }
 385   virtual BasicType memory_type() const { return T_ADDRESS; }
 386   // depends_only_on_test is almost always true, and needs to be almost always
 387   // true to enable key hoisting & commoning optimizations.  However, for the
 388   // special case of RawPtr loads from TLS top & end, the control edge carries
 389   // the dependence preventing hoisting past a Safepoint instead of the memory
 390   // edge.  (An unfortunate consequence of having Safepoints not set Raw
 391   // Memory; itself an unfortunate consequence of having Nodes which produce
 392   // results (new raw memory state) inside of loops preventing all manner of
 393   // other optimizations).  Basically, it's ugly but so is the alternative.
 394   // See comment in macro.cpp, around line 125 expand_allocate_common().
 395   virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
 396 };
 397 
 398 
 399 //------------------------------LoadNNode--------------------------------------
 400 // Load a narrow oop from memory (either object or array)
 401 class LoadNNode : public LoadNode {
 402 public:
 403   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, Sem sem)
 404     : LoadNode(c, mem, adr, at, t, sem) {}
 405   virtual int Opcode() const;
 406   virtual uint ideal_reg() const { return Op_RegN; }
 407   virtual int store_Opcode() const { return Op_StoreN; }
 408   virtual BasicType memory_type() const { return T_NARROWOOP; }
 409   // depends_only_on_test is almost always true, and needs to be almost always
 410   // true to enable key hoisting & commoning optimizations.  However, for the
 411   // special case of RawPtr loads from TLS top & end, the control edge carries
 412   // the dependence preventing hoisting past a Safepoint instead of the memory
 413   // edge.  (An unfortunate consequence of having Safepoints not set Raw
 414   // Memory; itself an unfortunate consequence of having Nodes which produce
 415   // results (new raw memory state) inside of loops preventing all manner of
 416   // other optimizations).  Basically, it's ugly but so is the alternative.
 417   // See comment in macro.cpp, around line 125 expand_allocate_common().
 418   virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
 419 };
 420 
 421 //------------------------------LoadKlassNode----------------------------------
 422 // Load a Klass from an object
 423 class LoadKlassNode : public LoadPNode {
 424 public:
 425   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, Sem sem)
 426     : LoadPNode(c, mem, adr, at, tk, sem) {}
 427   virtual int Opcode() const;
 428   virtual const Type *Value( PhaseTransform *phase ) const;
 429   virtual Node *Identity( PhaseTransform *phase );
 430   virtual bool depends_only_on_test() const { return true; }
 431 
 432   // Polymorphic factory method:
 433   static Node* make( PhaseGVN& gvn, Node *mem, Node *adr, const TypePtr* at,
 434                      const TypeKlassPtr *tk = TypeKlassPtr::OBJECT );
 435 };
 436 
 437 //------------------------------LoadNKlassNode---------------------------------
 438 // Load a narrow Klass from an object.
 439 class LoadNKlassNode : public LoadNNode {
 440 public:
 441   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, Sem sem)
 442     : LoadNNode(c, mem, adr, at, tk, sem) {}
 443   virtual int Opcode() const;
 444   virtual uint ideal_reg() const { return Op_RegN; }
 445   virtual int store_Opcode() const { return Op_StoreNKlass; }
 446   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 447 
 448   virtual const Type *Value( PhaseTransform *phase ) const;
 449   virtual Node *Identity( PhaseTransform *phase );
 450   virtual bool depends_only_on_test() const { return true; }
 451 };
 452 
 453 
 454 //------------------------------StoreNode--------------------------------------
 455 // Store value; requires Store, Address and Value
 456 class StoreNode : public MemNode {
 457 public:
 458   typedef enum { unordered = 0, release } Sem;
 459 private:
 460   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 461   // stores that can be reordered, and such requiring release semantics to
 462   // adhere to the Java specification.  The required behaviour is stored in
 463   // this field.
 464   const Sem _sem;
 465   // Needed for proper cloning.
 466   virtual uint size_of() const { return sizeof(*this); }
 467 protected:
 468   virtual uint cmp( const Node &n ) const;
 469   virtual bool depends_only_on_test() const { return false; }
 470 
 471   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 472   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 473 
 474 public:
 475   // We must ensure that stores of object references will be visible
 476   // only after the object's initialization. So the callers of this
 477   // procedure must indicate that the store requires `release'
 478   // semantics, if the stored value is an object reference that might
 479   // point to a new object and may become externally visible.
 480   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 481     : MemNode(c, mem, adr, at, val), _sem(sem) {
 482     init_class_id(Class_Store);
 483   }
 484   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, Sem sem)
 485     : MemNode(c, mem, adr, at, val, oop_store), _sem(sem) {
 486     init_class_id(Class_Store);
 487   }
 488 
 489   inline bool is_unordered() const { return !is_release(); }
 490   inline bool is_release() const {
 491     assert((_sem == unordered || _sem == release), "unexpected");
 492     return _sem == release;
 493   }
 494 
 495   // Conservatively release stores of object references in order to
 496   // ensure visibility of object initialization.
 497   static inline Sem release_if_reference(const BasicType t) {
 498     const Sem s = (t == T_ARRAY ||
 499                    t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 500                    t == T_OBJECT) ? release : unordered;
 501     return s;
 502   }
 503 
 504   // Polymorphic factory method
 505   //
 506   // We must ensure that stores of object references will be visible
 507   // only after the object's initialization. So the callers of this
 508   // procedure must indicate that the store requires `release'
 509   // semantics, if the stored value is an object reference that might
 510   // point to a new object and may become externally visible.
 511   static StoreNode* make(PhaseGVN& gvn, Node *c, Node *mem, Node *adr,
 512                          const TypePtr* at, Node *val, BasicType bt, Sem sem);
 513 
 514   virtual uint hash() const;    // Check the type
 515 
 516   // If the store is to Field memory and the pointer is non-null, we can
 517   // zero out the control input.
 518   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 519 
 520   // Compute a new Type for this node.  Basically we just do the pre-check,
 521   // then call the virtual add() to set the type.
 522   virtual const Type *Value( PhaseTransform *phase ) const;
 523 
 524   // Check for identity function on memory (Load then Store at same address)
 525   virtual Node *Identity( PhaseTransform *phase );
 526 
 527   // Do not match memory edge
 528   virtual uint match_edge(uint idx) const;
 529 
 530   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 531 
 532   // Map a store opcode to its corresponding own opcode, trivially.
 533   virtual int store_Opcode() const { return Opcode(); }
 534 
 535   // have all possible loads of the value stored been optimized away?
 536   bool value_never_loaded(PhaseTransform *phase) const;
 537 };
 538 
 539 //------------------------------StoreBNode-------------------------------------
 540 // Store byte to memory
 541 class StoreBNode : public StoreNode {
 542 public:
 543   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 544     : StoreNode(c, mem, adr, at, val, sem) {}
 545   virtual int Opcode() const;
 546   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 547   virtual BasicType memory_type() const { return T_BYTE; }
 548 };
 549 
 550 //------------------------------StoreCNode-------------------------------------
 551 // Store char/short to memory
 552 class StoreCNode : public StoreNode {
 553 public:
 554   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 555     : StoreNode(c, mem, adr, at, val, sem) {}
 556   virtual int Opcode() const;
 557   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 558   virtual BasicType memory_type() const { return T_CHAR; }
 559 };
 560 
 561 //------------------------------StoreINode-------------------------------------
 562 // Store int to memory
 563 class StoreINode : public StoreNode {
 564 public:
 565   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 566     : StoreNode(c, mem, adr, at, val, sem) {}
 567   virtual int Opcode() const;
 568   virtual BasicType memory_type() const { return T_INT; }
 569 };
 570 
 571 //------------------------------StoreLNode-------------------------------------
 572 // Store long to memory
 573 class StoreLNode : public StoreNode {
 574   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 575   virtual uint cmp( const Node &n ) const {
 576     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 577       && StoreNode::cmp(n);
 578   }
 579   virtual uint size_of() const { return sizeof(*this); }
 580   const bool _require_atomic_access;  // is piecewise store forbidden?
 581 
 582 public:
 583   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, bool require_atomic_access, Sem sem)
 584     : StoreNode(c, mem, adr, at, val, sem), _require_atomic_access(require_atomic_access) {}
 585   virtual int Opcode() const;
 586   virtual BasicType memory_type() const { return T_LONG; }
 587   bool require_atomic_access() { return _require_atomic_access; }
 588   static StoreLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, Sem sem);
 589 #ifndef PRODUCT
 590   virtual void dump_spec(outputStream *st) const {
 591     StoreNode::dump_spec(st);
 592     if (_require_atomic_access)  st->print(" Atomic!");
 593   }
 594 #endif
 595 };
 596 
 597 //------------------------------StoreFNode-------------------------------------
 598 // Store float to memory
 599 class StoreFNode : public StoreNode {
 600 public:
 601   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 602     : StoreNode(c, mem, adr, at, val, sem) {}
 603   virtual int Opcode() const;
 604   virtual BasicType memory_type() const { return T_FLOAT; }
 605 };
 606 
 607 //------------------------------StoreDNode-------------------------------------
 608 // Store double to memory
 609 class StoreDNode : public StoreNode {
 610 public:
 611   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 612     : StoreNode(c, mem, adr, at, val, sem) {}
 613   virtual int Opcode() const;
 614   virtual BasicType memory_type() const { return T_DOUBLE; }
 615 };
 616 
 617 //------------------------------StorePNode-------------------------------------
 618 // Store pointer to memory
 619 class StorePNode : public StoreNode {
 620 public:
 621   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 622     : StoreNode(c, mem, adr, at, val, sem) {}
 623   virtual int Opcode() const;
 624   virtual BasicType memory_type() const { return T_ADDRESS; }
 625 };
 626 
 627 //------------------------------StoreNNode-------------------------------------
 628 // Store narrow oop to memory
 629 class StoreNNode : public StoreNode {
 630 public:
 631   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 632     : StoreNode(c, mem, adr, at, val, sem) {}
 633   virtual int Opcode() const;
 634   virtual BasicType memory_type() const { return T_NARROWOOP; }
 635 };
 636 
 637 //------------------------------StoreNKlassNode--------------------------------------
 638 // Store narrow klass to memory
 639 class StoreNKlassNode : public StoreNNode {
 640 public:
 641   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Sem sem)
 642     : StoreNNode(c, mem, adr, at, val, sem) {}
 643   virtual int Opcode() const;
 644   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 645 };
 646 
 647 //------------------------------StoreCMNode-----------------------------------
 648 // Store card-mark byte to memory for CM
 649 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store
 650 // Preceeding equivalent StoreCMs may be eliminated.
 651 class StoreCMNode : public StoreNode {
 652  private:
 653   virtual uint hash() const { return StoreNode::hash() + _oop_alias_idx; }
 654   virtual uint cmp( const Node &n ) const {
 655     return _oop_alias_idx == ((StoreCMNode&)n)._oop_alias_idx
 656       && StoreNode::cmp(n);
 657   }
 658   virtual uint size_of() const { return sizeof(*this); }
 659   int _oop_alias_idx;   // The alias_idx of OopStore
 660 
 661 public:
 662   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, int oop_alias_idx ) :
 663     StoreNode(c, mem, adr, at, val, oop_store, StoreNode::release),
 664     _oop_alias_idx(oop_alias_idx) {
 665     assert(_oop_alias_idx >= Compile::AliasIdxRaw ||
 666            _oop_alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
 667            "bad oop alias idx");
 668   }
 669   virtual int Opcode() const;
 670   virtual Node *Identity( PhaseTransform *phase );
 671   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 672   virtual const Type *Value( PhaseTransform *phase ) const;
 673   virtual BasicType memory_type() const { return T_VOID; } // unspecific
 674   int oop_alias_idx() const { return _oop_alias_idx; }
 675 };
 676 
 677 //------------------------------LoadPLockedNode---------------------------------
 678 // Load-locked a pointer from memory (either object or array).
 679 // On Sparc & Intel this is implemented as a normal pointer load.
 680 // On PowerPC and friends it's a real load-locked.
 681 class LoadPLockedNode : public LoadPNode {
 682 public:
 683   LoadPLockedNode(Node *c, Node *mem, Node *adr, Sem sem)
 684     : LoadPNode(c, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM, sem) {}
 685   virtual int Opcode() const;
 686   virtual int store_Opcode() const { return Op_StorePConditional; }
 687   virtual bool depends_only_on_test() const { return true; }
 688 };
 689 
 690 //------------------------------SCMemProjNode---------------------------------------
 691 // This class defines a projection of the memory  state of a store conditional node.
 692 // These nodes return a value, but also update memory.
 693 class SCMemProjNode : public ProjNode {
 694 public:
 695   enum {SCMEMPROJCON = (uint)-2};
 696   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 697   virtual int Opcode() const;
 698   virtual bool      is_CFG() const  { return false; }
 699   virtual const Type *bottom_type() const {return Type::MEMORY;}
 700   virtual const TypePtr *adr_type() const { return in(0)->in(MemNode::Memory)->adr_type();}
 701   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 702   virtual const Type *Value( PhaseTransform *phase ) const;
 703 #ifndef PRODUCT
 704   virtual void dump_spec(outputStream *st) const {};
 705 #endif
 706 };
 707 
 708 //------------------------------LoadStoreNode---------------------------
 709 // Note: is_Mem() method returns 'true' for this class.
 710 class LoadStoreNode : public Node {
 711 private:
 712   const Type* const _type;      // What kind of value is loaded?
 713   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 714   virtual uint size_of() const; // Size is bigger
 715 public:
 716   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 717   virtual bool depends_only_on_test() const { return false; }
 718   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 719 
 720   virtual const Type *bottom_type() const { return _type; }
 721   virtual uint ideal_reg() const;
 722   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 723 
 724   bool result_not_used() const;
 725 };
 726 
 727 class LoadStoreConditionalNode : public LoadStoreNode {
 728 public:
 729   enum {
 730     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 731   };
 732   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 733 };
 734 
 735 //------------------------------StorePConditionalNode---------------------------
 736 // Conditionally store pointer to memory, if no change since prior
 737 // load-locked.  Sets flags for success or failure of the store.
 738 class StorePConditionalNode : public LoadStoreConditionalNode {
 739 public:
 740   StorePConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 741   virtual int Opcode() const;
 742   // Produces flags
 743   virtual uint ideal_reg() const { return Op_RegFlags; }
 744 };
 745 
 746 //------------------------------StoreIConditionalNode---------------------------
 747 // Conditionally store int to memory, if no change since prior
 748 // load-locked.  Sets flags for success or failure of the store.
 749 class StoreIConditionalNode : public LoadStoreConditionalNode {
 750 public:
 751   StoreIConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ii ) : LoadStoreConditionalNode(c, mem, adr, val, ii) { }
 752   virtual int Opcode() const;
 753   // Produces flags
 754   virtual uint ideal_reg() const { return Op_RegFlags; }
 755 };
 756 
 757 //------------------------------StoreLConditionalNode---------------------------
 758 // Conditionally store long to memory, if no change since prior
 759 // load-locked.  Sets flags for success or failure of the store.
 760 class StoreLConditionalNode : public LoadStoreConditionalNode {
 761 public:
 762   StoreLConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreConditionalNode(c, mem, adr, val, ll) { }
 763   virtual int Opcode() const;
 764   // Produces flags
 765   virtual uint ideal_reg() const { return Op_RegFlags; }
 766 };
 767 
 768 
 769 //------------------------------CompareAndSwapLNode---------------------------
 770 class CompareAndSwapLNode : public LoadStoreConditionalNode {
 771 public:
 772   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 773   virtual int Opcode() const;
 774 };
 775 
 776 
 777 //------------------------------CompareAndSwapINode---------------------------
 778 class CompareAndSwapINode : public LoadStoreConditionalNode {
 779 public:
 780   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 781   virtual int Opcode() const;
 782 };
 783 
 784 
 785 //------------------------------CompareAndSwapPNode---------------------------
 786 class CompareAndSwapPNode : public LoadStoreConditionalNode {
 787 public:
 788   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 789   virtual int Opcode() const;
 790 };
 791 
 792 //------------------------------CompareAndSwapNNode---------------------------
 793 class CompareAndSwapNNode : public LoadStoreConditionalNode {
 794 public:
 795   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreConditionalNode(c, mem, adr, val, ex) { }
 796   virtual int Opcode() const;
 797 };
 798 
 799 //------------------------------GetAndAddINode---------------------------
 800 class GetAndAddINode : public LoadStoreNode {
 801 public:
 802   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
 803   virtual int Opcode() const;
 804 };
 805 
 806 //------------------------------GetAndAddLNode---------------------------
 807 class GetAndAddLNode : public LoadStoreNode {
 808 public:
 809   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
 810   virtual int Opcode() const;
 811 };
 812 
 813 
 814 //------------------------------GetAndSetINode---------------------------
 815 class GetAndSetINode : public LoadStoreNode {
 816 public:
 817   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
 818   virtual int Opcode() const;
 819 };
 820 
 821 //------------------------------GetAndSetINode---------------------------
 822 class GetAndSetLNode : public LoadStoreNode {
 823 public:
 824   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
 825   virtual int Opcode() const;
 826 };
 827 
 828 //------------------------------GetAndSetPNode---------------------------
 829 class GetAndSetPNode : public LoadStoreNode {
 830 public:
 831   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
 832   virtual int Opcode() const;
 833 };
 834 
 835 //------------------------------GetAndSetNNode---------------------------
 836 class GetAndSetNNode : public LoadStoreNode {
 837 public:
 838   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
 839   virtual int Opcode() const;
 840 };
 841 
 842 //------------------------------ClearArray-------------------------------------
 843 class ClearArrayNode: public Node {
 844 public:
 845   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base )
 846     : Node(ctrl,arymem,word_cnt,base) {
 847     init_class_id(Class_ClearArray);
 848   }
 849   virtual int         Opcode() const;
 850   virtual const Type *bottom_type() const { return Type::MEMORY; }
 851   // ClearArray modifies array elements, and so affects only the
 852   // array memory addressed by the bottom_type of its base address.
 853   virtual const class TypePtr *adr_type() const;
 854   virtual Node *Identity( PhaseTransform *phase );
 855   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 856   virtual uint match_edge(uint idx) const;
 857 
 858   // Clear the given area of an object or array.
 859   // The start offset must always be aligned mod BytesPerInt.
 860   // The end offset must always be aligned mod BytesPerLong.
 861   // Return the new memory.
 862   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 863                             intptr_t start_offset,
 864                             intptr_t end_offset,
 865                             PhaseGVN* phase);
 866   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 867                             intptr_t start_offset,
 868                             Node* end_offset,
 869                             PhaseGVN* phase);
 870   static Node* clear_memory(Node* control, Node* mem, Node* dest,
 871                             Node* start_offset,
 872                             Node* end_offset,
 873                             PhaseGVN* phase);
 874   // Return allocation input memory edge if it is different instance
 875   // or itself if it is the one we are looking for.
 876   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
 877 };
 878 
 879 //------------------------------StrIntrinsic-------------------------------
 880 // Base class for Ideal nodes used in String instrinsic code.
 881 class StrIntrinsicNode: public Node {
 882 public:
 883   StrIntrinsicNode(Node* control, Node* char_array_mem,
 884                    Node* s1, Node* c1, Node* s2, Node* c2):
 885     Node(control, char_array_mem, s1, c1, s2, c2) {
 886   }
 887 
 888   StrIntrinsicNode(Node* control, Node* char_array_mem,
 889                    Node* s1, Node* s2, Node* c):
 890     Node(control, char_array_mem, s1, s2, c) {
 891   }
 892 
 893   StrIntrinsicNode(Node* control, Node* char_array_mem,
 894                    Node* s1, Node* s2):
 895     Node(control, char_array_mem, s1, s2) {
 896   }
 897 
 898   virtual bool depends_only_on_test() const { return false; }
 899   virtual const TypePtr* adr_type() const { return TypeAryPtr::CHARS; }
 900   virtual uint match_edge(uint idx) const;
 901   virtual uint ideal_reg() const { return Op_RegI; }
 902   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 903   virtual const Type *Value(PhaseTransform *phase) const;
 904 };
 905 
 906 //------------------------------StrComp-------------------------------------
 907 class StrCompNode: public StrIntrinsicNode {
 908 public:
 909   StrCompNode(Node* control, Node* char_array_mem,
 910               Node* s1, Node* c1, Node* s2, Node* c2):
 911     StrIntrinsicNode(control, char_array_mem, s1, c1, s2, c2) {};
 912   virtual int Opcode() const;
 913   virtual const Type* bottom_type() const { return TypeInt::INT; }
 914 };
 915 
 916 //------------------------------StrEquals-------------------------------------
 917 class StrEqualsNode: public StrIntrinsicNode {
 918 public:
 919   StrEqualsNode(Node* control, Node* char_array_mem,
 920                 Node* s1, Node* s2, Node* c):
 921     StrIntrinsicNode(control, char_array_mem, s1, s2, c) {};
 922   virtual int Opcode() const;
 923   virtual const Type* bottom_type() const { return TypeInt::BOOL; }
 924 };
 925 
 926 //------------------------------StrIndexOf-------------------------------------
 927 class StrIndexOfNode: public StrIntrinsicNode {
 928 public:
 929   StrIndexOfNode(Node* control, Node* char_array_mem,
 930               Node* s1, Node* c1, Node* s2, Node* c2):
 931     StrIntrinsicNode(control, char_array_mem, s1, c1, s2, c2) {};
 932   virtual int Opcode() const;
 933   virtual const Type* bottom_type() const { return TypeInt::INT; }
 934 };
 935 
 936 //------------------------------AryEq---------------------------------------
 937 class AryEqNode: public StrIntrinsicNode {
 938 public:
 939   AryEqNode(Node* control, Node* char_array_mem, Node* s1, Node* s2):
 940     StrIntrinsicNode(control, char_array_mem, s1, s2) {};
 941   virtual int Opcode() const;
 942   virtual const Type* bottom_type() const { return TypeInt::BOOL; }
 943 };
 944 
 945 
 946 //------------------------------EncodeISOArray--------------------------------
 947 // encode char[] to byte[] in ISO_8859_1
 948 class EncodeISOArrayNode: public Node {
 949 public:
 950   EncodeISOArrayNode(Node *control, Node* arymem, Node* s1, Node* s2, Node* c): Node(control, arymem, s1, s2, c) {};
 951   virtual int Opcode() const;
 952   virtual bool depends_only_on_test() const { return false; }
 953   virtual const Type* bottom_type() const { return TypeInt::INT; }
 954   virtual const TypePtr* adr_type() const { return TypePtr::BOTTOM; }
 955   virtual uint match_edge(uint idx) const;
 956   virtual uint ideal_reg() const { return Op_RegI; }
 957   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 958   virtual const Type *Value(PhaseTransform *phase) const;
 959 };
 960 
 961 //------------------------------MemBar-----------------------------------------
 962 // There are different flavors of Memory Barriers to match the Java Memory
 963 // Model.  Monitor-enter and volatile-load act as Aquires: no following ref
 964 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
 965 // volatile-load.  Monitor-exit and volatile-store act as Release: no
 966 // preceding ref can be moved to after them.  We insert a MemBar-Release
 967 // before a FastUnlock or volatile-store.  All volatiles need to be
 968 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
 969 // separate it from any following volatile-load.
 970 class MemBarNode: public MultiNode {
 971   virtual uint hash() const ;                  // { return NO_HASH; }
 972   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
 973 
 974   virtual uint size_of() const { return sizeof(*this); }
 975   // Memory type this node is serializing.  Usually either rawptr or bottom.
 976   const TypePtr* _adr_type;
 977 
 978 public:
 979   enum {
 980     Precedent = TypeFunc::Parms  // optional edge to force precedence
 981   };
 982   MemBarNode(Compile* C, int alias_idx, Node* precedent);
 983   virtual int Opcode() const = 0;
 984   virtual const class TypePtr *adr_type() const { return _adr_type; }
 985   virtual const Type *Value( PhaseTransform *phase ) const;
 986   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 987   virtual uint match_edge(uint idx) const { return 0; }
 988   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
 989   virtual Node *match( const ProjNode *proj, const Matcher *m );
 990   // Factory method.  Builds a wide or narrow membar.
 991   // Optional 'precedent' becomes an extra edge if not null.
 992   static MemBarNode* make(Compile* C, int opcode,
 993                           int alias_idx = Compile::AliasIdxBot,
 994                           Node* precedent = NULL);
 995 };
 996 
 997 // "Acquire" - no following ref can move before (but earlier refs can
 998 // follow, like an early Load stalled in cache).  Requires multi-cpu
 999 // visibility.  Inserted after a volatile load.
1000 class MemBarAcquireNode: public MemBarNode {
1001 public:
1002   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1003     : MemBarNode(C, alias_idx, precedent) {}
1004   virtual int Opcode() const;
1005 };
1006 
1007 // "Release" - no earlier ref can move after (but later refs can move
1008 // up, like a speculative pipelined cache-hitting Load).  Requires
1009 // multi-cpu visibility.  Inserted before a volatile store.
1010 class MemBarReleaseNode: public MemBarNode {
1011 public:
1012   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1013     : MemBarNode(C, alias_idx, precedent) {}
1014   virtual int Opcode() const;
1015 };
1016 
1017 // "Acquire" - no following ref can move before (but earlier refs can
1018 // follow, like an early Load stalled in cache).  Requires multi-cpu
1019 // visibility.  Inserted after a FastLock.
1020 class MemBarAcquireLockNode: public MemBarNode {
1021 public:
1022   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1023     : MemBarNode(C, alias_idx, precedent) {}
1024   virtual int Opcode() const;
1025 };
1026 
1027 // "Release" - no earlier ref can move after (but later refs can move
1028 // up, like a speculative pipelined cache-hitting Load).  Requires
1029 // multi-cpu visibility.  Inserted before a FastUnLock.
1030 class MemBarReleaseLockNode: public MemBarNode {
1031 public:
1032   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1033     : MemBarNode(C, alias_idx, precedent) {}
1034   virtual int Opcode() const;
1035 };
1036 
1037 class MemBarStoreStoreNode: public MemBarNode {
1038 public:
1039   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1040     : MemBarNode(C, alias_idx, precedent) {
1041     init_class_id(Class_MemBarStoreStore);
1042   }
1043   virtual int Opcode() const;
1044 };
1045 
1046 // Ordering between a volatile store and a following volatile load.
1047 // Requires multi-CPU visibility?
1048 class MemBarVolatileNode: public MemBarNode {
1049 public:
1050   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1051     : MemBarNode(C, alias_idx, precedent) {}
1052   virtual int Opcode() const;
1053 };
1054 
1055 // Ordering within the same CPU.  Used to order unsafe memory references
1056 // inside the compiler when we lack alias info.  Not needed "outside" the
1057 // compiler because the CPU does all the ordering for us.
1058 class MemBarCPUOrderNode: public MemBarNode {
1059 public:
1060   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1061     : MemBarNode(C, alias_idx, precedent) {}
1062   virtual int Opcode() const;
1063   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1064 };
1065 
1066 // Isolation of object setup after an AllocateNode and before next safepoint.
1067 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1068 class InitializeNode: public MemBarNode {
1069   friend class AllocateNode;
1070 
1071   enum {
1072     Incomplete    = 0,
1073     Complete      = 1,
1074     WithArraycopy = 2
1075   };
1076   int _is_complete;
1077 
1078   bool _does_not_escape;
1079 
1080 public:
1081   enum {
1082     Control    = TypeFunc::Control,
1083     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1084     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1085     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1086   };
1087 
1088   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1089   virtual int Opcode() const;
1090   virtual uint size_of() const { return sizeof(*this); }
1091   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1092   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1093 
1094   // Manage incoming memory edges via a MergeMem on in(Memory):
1095   Node* memory(uint alias_idx);
1096 
1097   // The raw memory edge coming directly from the Allocation.
1098   // The contents of this memory are *always* all-zero-bits.
1099   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1100 
1101   // Return the corresponding allocation for this initialization (or null if none).
1102   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1103   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1104   AllocateNode* allocation();
1105 
1106   // Anything other than zeroing in this init?
1107   bool is_non_zero();
1108 
1109   // An InitializeNode must completed before macro expansion is done.
1110   // Completion requires that the AllocateNode must be followed by
1111   // initialization of the new memory to zero, then to any initializers.
1112   bool is_complete() { return _is_complete != Incomplete; }
1113   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1114 
1115   // Mark complete.  (Must not yet be complete.)
1116   void set_complete(PhaseGVN* phase);
1117   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1118 
1119   bool does_not_escape() { return _does_not_escape; }
1120   void set_does_not_escape() { _does_not_escape = true; }
1121 
1122 #ifdef ASSERT
1123   // ensure all non-degenerate stores are ordered and non-overlapping
1124   bool stores_are_sane(PhaseTransform* phase);
1125 #endif //ASSERT
1126 
1127   // See if this store can be captured; return offset where it initializes.
1128   // Return 0 if the store cannot be moved (any sort of problem).
1129   intptr_t can_capture_store(StoreNode* st, PhaseTransform* phase, bool can_reshape);
1130 
1131   // Capture another store; reformat it to write my internal raw memory.
1132   // Return the captured copy, else NULL if there is some sort of problem.
1133   Node* capture_store(StoreNode* st, intptr_t start, PhaseTransform* phase, bool can_reshape);
1134 
1135   // Find captured store which corresponds to the range [start..start+size).
1136   // Return my own memory projection (meaning the initial zero bits)
1137   // if there is no such store.  Return NULL if there is a problem.
1138   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);
1139 
1140   // Called when the associated AllocateNode is expanded into CFG.
1141   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1142                         intptr_t header_size, Node* size_in_bytes,
1143                         PhaseGVN* phase);
1144 
1145  private:
1146   void remove_extra_zeroes();
1147 
1148   // Find out where a captured store should be placed (or already is placed).
1149   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1150                                      PhaseTransform* phase);
1151 
1152   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);
1153 
1154   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);
1155 
1156   bool detect_init_independence(Node* n, int& count);
1157 
1158   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1159                                PhaseGVN* phase);
1160 
1161   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1162 };
1163 
1164 //------------------------------MergeMem---------------------------------------
1165 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1166 class MergeMemNode: public Node {
1167   virtual uint hash() const ;                  // { return NO_HASH; }
1168   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self
1169   friend class MergeMemStream;
1170   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1171 
1172 public:
1173   // If the input is a whole memory state, clone it with all its slices intact.
1174   // Otherwise, make a new memory state with just that base memory input.
1175   // In either case, the result is a newly created MergeMem.
1176   static MergeMemNode* make(Compile* C, Node* base_memory);
1177 
1178   virtual int Opcode() const;
1179   virtual Node *Identity( PhaseTransform *phase );
1180   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1181   virtual uint ideal_reg() const { return NotAMachineReg; }
1182   virtual uint match_edge(uint idx) const { return 0; }
1183   virtual const RegMask &out_RegMask() const;
1184   virtual const Type *bottom_type() const { return Type::MEMORY; }
1185   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1186   // sparse accessors
1187   // Fetch the previously stored "set_memory_at", or else the base memory.
1188   // (Caller should clone it if it is a phi-nest.)
1189   Node* memory_at(uint alias_idx) const;
1190   // set the memory, regardless of its previous value
1191   void set_memory_at(uint alias_idx, Node* n);
1192   // the "base" is the memory that provides the non-finite support
1193   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1194   // warning: setting the base can implicitly set any of the other slices too
1195   void set_base_memory(Node* def);
1196   // sentinel value which denotes a copy of the base memory:
1197   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1198   static Node* make_empty_memory(); // where the sentinel comes from
1199   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1200   // hook for the iterator, to perform any necessary setup
1201   void iteration_setup(const MergeMemNode* other = NULL);
1202   // push sentinels until I am at least as long as the other (semantic no-op)
1203   void grow_to_match(const MergeMemNode* other);
1204   bool verify_sparse() const PRODUCT_RETURN0;
1205 #ifndef PRODUCT
1206   virtual void dump_spec(outputStream *st) const;
1207 #endif
1208 };
1209 
1210 class MergeMemStream : public StackObj {
1211  private:
1212   MergeMemNode*       _mm;
1213   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1214   Node*               _mm_base;  // loop-invariant base memory of _mm
1215   int                 _idx;
1216   int                 _cnt;
1217   Node*               _mem;
1218   Node*               _mem2;
1219   int                 _cnt2;
1220 
1221   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {
1222     // subsume_node will break sparseness at times, whenever a memory slice
1223     // folds down to a copy of the base ("fat") memory.  In such a case,
1224     // the raw edge will update to base, although it should be top.
1225     // This iterator will recognize either top or base_memory as an
1226     // "empty" slice.  See is_empty, is_empty2, and next below.
1227     //
1228     // The sparseness property is repaired in MergeMemNode::Ideal.
1229     // As long as access to a MergeMem goes through this iterator
1230     // or the memory_at accessor, flaws in the sparseness will
1231     // never be observed.
1232     //
1233     // Also, iteration_setup repairs sparseness.
1234     assert(mm->verify_sparse(), "please, no dups of base");
1235     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");
1236 
1237     _mm  = mm;
1238     _mm_base = mm->base_memory();
1239     _mm2 = mm2;
1240     _cnt = mm->req();
1241     _idx = Compile::AliasIdxBot-1; // start at the base memory
1242     _mem = NULL;
1243     _mem2 = NULL;
1244   }
1245 
1246 #ifdef ASSERT
1247   Node* check_memory() const {
1248     if (at_base_memory())
1249       return _mm->base_memory();
1250     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1251       return _mm->memory_at(_idx);
1252     else
1253       return _mm_base;
1254   }
1255   Node* check_memory2() const {
1256     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1257   }
1258 #endif
1259 
1260   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1261   void assert_synch() const {
1262     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1263            "no side-effects except through the stream");
1264   }
1265 
1266  public:
1267 
1268   // expected usages:
1269   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1270   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1271 
1272   // iterate over one merge
1273   MergeMemStream(MergeMemNode* mm) {
1274     mm->iteration_setup();
1275     init(mm);
1276     debug_only(_cnt2 = 999);
1277   }
1278   // iterate in parallel over two merges
1279   // only iterates through non-empty elements of mm2
1280   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1281     assert(mm2, "second argument must be a MergeMem also");
1282     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1283     mm->iteration_setup(mm2);
1284     init(mm, mm2);
1285     _cnt2 = mm2->req();
1286   }
1287 #ifdef ASSERT
1288   ~MergeMemStream() {
1289     assert_synch();
1290   }
1291 #endif
1292 
1293   MergeMemNode* all_memory() const {
1294     return _mm;
1295   }
1296   Node* base_memory() const {
1297     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1298     return _mm_base;
1299   }
1300   const MergeMemNode* all_memory2() const {
1301     assert(_mm2 != NULL, "");
1302     return _mm2;
1303   }
1304   bool at_base_memory() const {
1305     return _idx == Compile::AliasIdxBot;
1306   }
1307   int alias_idx() const {
1308     assert(_mem, "must call next 1st");
1309     return _idx;
1310   }
1311 
1312   const TypePtr* adr_type() const {
1313     return Compile::current()->get_adr_type(alias_idx());
1314   }
1315 
1316   const TypePtr* adr_type(Compile* C) const {
1317     return C->get_adr_type(alias_idx());
1318   }
1319   bool is_empty() const {
1320     assert(_mem, "must call next 1st");
1321     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1322     return _mem->is_top();
1323   }
1324   bool is_empty2() const {
1325     assert(_mem2, "must call next 1st");
1326     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1327     return _mem2->is_top();
1328   }
1329   Node* memory() const {
1330     assert(!is_empty(), "must not be empty");
1331     assert_synch();
1332     return _mem;
1333   }
1334   // get the current memory, regardless of empty or non-empty status
1335   Node* force_memory() const {
1336     assert(!is_empty() || !at_base_memory(), "");
1337     // Use _mm_base to defend against updates to _mem->base_memory().
1338     Node *mem = _mem->is_top() ? _mm_base : _mem;
1339     assert(mem == check_memory(), "");
1340     return mem;
1341   }
1342   Node* memory2() const {
1343     assert(_mem2 == check_memory2(), "");
1344     return _mem2;
1345   }
1346   void set_memory(Node* mem) {
1347     if (at_base_memory()) {
1348       // Note that this does not change the invariant _mm_base.
1349       _mm->set_base_memory(mem);
1350     } else {
1351       _mm->set_memory_at(_idx, mem);
1352     }
1353     _mem = mem;
1354     assert_synch();
1355   }
1356 
1357   // Recover from a side effect to the MergeMemNode.
1358   void set_memory() {
1359     _mem = _mm->in(_idx);
1360   }
1361 
1362   bool next()  { return next(false); }
1363   bool next2() { return next(true); }
1364 
1365   bool next_non_empty()  { return next_non_empty(false); }
1366   bool next_non_empty2() { return next_non_empty(true); }
1367   // next_non_empty2 can yield states where is_empty() is true
1368 
1369  private:
1370   // find the next item, which might be empty
1371   bool next(bool have_mm2) {
1372     assert((_mm2 != NULL) == have_mm2, "use other next");
1373     assert_synch();
1374     if (++_idx < _cnt) {
1375       // Note:  This iterator allows _mm to be non-sparse.
1376       // It behaves the same whether _mem is top or base_memory.
1377       _mem = _mm->in(_idx);
1378       if (have_mm2)
1379         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1380       return true;
1381     }
1382     return false;
1383   }
1384 
1385   // find the next non-empty item
1386   bool next_non_empty(bool have_mm2) {
1387     while (next(have_mm2)) {
1388       if (!is_empty()) {
1389         // make sure _mem2 is filled in sensibly
1390         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1391         return true;
1392       } else if (have_mm2 && !is_empty2()) {
1393         return true;   // is_empty() == true
1394       }
1395     }
1396     return false;
1397   }
1398 };
1399 
1400 //------------------------------Prefetch---------------------------------------
1401 
1402 // Non-faulting prefetch load.  Prefetch for many reads.
1403 class PrefetchReadNode : public Node {
1404 public:
1405   PrefetchReadNode(Node *abio, Node *adr) : Node(0,abio,adr) {}
1406   virtual int Opcode() const;
1407   virtual uint ideal_reg() const { return NotAMachineReg; }
1408   virtual uint match_edge(uint idx) const { return idx==2; }
1409   virtual const Type *bottom_type() const { return Type::ABIO; }
1410 };
1411 
1412 // Non-faulting prefetch load.  Prefetch for many reads & many writes.
1413 class PrefetchWriteNode : public Node {
1414 public:
1415   PrefetchWriteNode(Node *abio, Node *adr) : Node(0,abio,adr) {}
1416   virtual int Opcode() const;
1417   virtual uint ideal_reg() const { return NotAMachineReg; }
1418   virtual uint match_edge(uint idx) const { return idx==2; }
1419   virtual const Type *bottom_type() const { return Type::ABIO; }
1420 };
1421 
1422 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1423 class PrefetchAllocationNode : public Node {
1424 public:
1425   PrefetchAllocationNode(Node *mem, Node *adr) : Node(0,mem,adr) {}
1426   virtual int Opcode() const;
1427   virtual uint ideal_reg() const { return NotAMachineReg; }
1428   virtual uint match_edge(uint idx) const { return idx==2; }
1429   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1430 };
1431 
1432 #endif // SHARE_VM_OPTO_MEMNODE_HPP