1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_OPTO_MEMNODE_HPP
  26 #define SHARE_OPTO_MEMNODE_HPP
  27 
  28 #include "opto/multnode.hpp"
  29 #include "opto/node.hpp"
  30 #include "opto/opcodes.hpp"
  31 #include "opto/type.hpp"
  32 
  33 // Portions of code courtesy of Clifford Click
  34 
  35 class MultiNode;
  36 class PhaseCCP;
  37 class PhaseTransform;
  38 
  39 //------------------------------MemNode----------------------------------------
  40 // Load or Store, possibly throwing a NULL pointer exception
  41 class MemNode : public Node {
  42 private:
  43   bool _unaligned_access; // Unaligned access from unsafe
  44   bool _mismatched_access; // Mismatched access from unsafe: byte read in integer array for instance
  45   bool _unsafe_access;     // Access of unsafe origin.
  46   uint8_t _barrier_data;   // Bit field with barrier information
  47 
  48 protected:
  49 #ifdef ASSERT
  50   const TypePtr* _adr_type;     // What kind of memory is being addressed?
  51 #endif
  52   virtual uint size_of() const;
  53 public:
  54   enum { Control,               // When is it safe to do this load?
  55          Memory,                // Chunk of memory is being loaded from
  56          Address,               // Actually address, derived from base
  57          ValueIn,               // Value to store
  58          OopStore               // Preceding oop store, only in StoreCM
  59   };
  60   typedef enum { unordered = 0,
  61                  acquire,       // Load has to acquire or be succeeded by MemBarAcquire.
  62                  release,       // Store has to release or be preceded by MemBarRelease.
  63                  seqcst,        // LoadStore has to have both acquire and release semantics.
  64                  unset          // The memory ordering is not set (used for testing)
  65   } MemOrd;
  66 protected:
  67   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at ) :
  68       Node(c0,c1,c2),
  69       _unaligned_access(false),
  70       _mismatched_access(false),
  71       _unsafe_access(false),
  72       _barrier_data(0) {
  73     init_class_id(Class_Mem);
  74     debug_only(_adr_type=at; adr_type();)
  75   }
  76   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 ) :
  77       Node(c0,c1,c2,c3),
  78       _unaligned_access(false),
  79       _mismatched_access(false),
  80       _unsafe_access(false),
  81       _barrier_data(0) {
  82     init_class_id(Class_Mem);
  83     debug_only(_adr_type=at; adr_type();)
  84   }
  85   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4) :
  86       Node(c0,c1,c2,c3,c4),
  87       _unaligned_access(false),
  88       _mismatched_access(false),
  89       _unsafe_access(false),
  90       _barrier_data(0) {
  91     init_class_id(Class_Mem);
  92     debug_only(_adr_type=at; adr_type();)
  93   }
  94 
  95   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { return NULL; }
  96   ArrayCopyNode* find_array_copy_clone(PhaseTransform* phase, Node* ld_alloc, Node* mem) const;
  97   static bool check_if_adr_maybe_raw(Node* adr);
  98 
  99 public:
 100   // Helpers for the optimizer.  Documented in memnode.cpp.
 101   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
 102                                       Node* p2, AllocateNode* a2,
 103                                       PhaseTransform* phase);
 104   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
 105 
 106   static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
 107   static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
 108   // This one should probably be a phase-specific function:
 109   static bool all_controls_dominate(Node* dom, Node* sub);
 110 
 111   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
 112 
 113   // Shared code for Ideal methods:
 114   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.
 115 
 116   // Helper function for adr_type() implementations.
 117   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);
 118 
 119   // Raw access function, to allow copying of adr_type efficiently in
 120   // product builds and retain the debug info for debug builds.
 121   const TypePtr *raw_adr_type() const {
 122 #ifdef ASSERT
 123     return _adr_type;
 124 #else
 125     return 0;
 126 #endif
 127   }
 128 
 129 #ifdef ASSERT
 130   void set_adr_type(const TypePtr* adr_type) { _adr_type = adr_type; }
 131 #endif
 132 
 133   // Map a load or store opcode to its corresponding store opcode.
 134   // (Return -1 if unknown.)
 135   virtual int store_Opcode() const { return -1; }
 136 
 137   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 138   virtual BasicType memory_type() const = 0;
 139   virtual int memory_size() const {
 140 #ifdef ASSERT
 141     return type2aelembytes(memory_type(), true);
 142 #else
 143     return type2aelembytes(memory_type());
 144 #endif
 145   }
 146 
 147   uint8_t barrier_data() { return _barrier_data; }
 148   void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
 149 
 150   // Search through memory states which precede this node (load or store).
 151   // Look for an exact match for the address, with no intervening
 152   // aliased stores.
 153   Node* find_previous_store(PhaseTransform* phase);
 154 
 155   // Can this node (load or store) accurately see a stored value in
 156   // the given memory state?  (The state may or may not be in(Memory).)
 157   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;
 158 
 159   void set_unaligned_access() { _unaligned_access = true; }
 160   bool is_unaligned_access() const { return _unaligned_access; }
 161   void set_mismatched_access() { _mismatched_access = true; }
 162   bool is_mismatched_access() const { return _mismatched_access; }
 163   void set_unsafe_access() { _unsafe_access = true; }
 164   bool is_unsafe_access() const { return _unsafe_access; }
 165 
 166 #ifndef PRODUCT
 167   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 168   virtual void dump_spec(outputStream *st) const;
 169 #endif
 170 };
 171 
 172 //------------------------------LoadNode---------------------------------------
 173 // Load value; requires Memory and Address
 174 class LoadNode : public MemNode {
 175 public:
 176   // Some loads (from unsafe) should be pinned: they don't depend only
 177   // on the dominating test.  The field _control_dependency below records
 178   // whether that node depends only on the dominating test.
 179   // Pinned and UnknownControl are similar, but differ in that Pinned
 180   // loads are not allowed to float across safepoints, whereas UnknownControl
 181   // loads are allowed to do that. Therefore, Pinned is stricter.
 182   enum ControlDependency {
 183     Pinned,
 184     UnknownControl,
 185     DependsOnlyOnTest
 186   };
 187 
 188 private:
 189   // LoadNode::hash() doesn't take the _control_dependency field
 190   // into account: If the graph already has a non-pinned LoadNode and
 191   // we add a pinned LoadNode with the same inputs, it's safe for GVN
 192   // to replace the pinned LoadNode with the non-pinned LoadNode,
 193   // otherwise it wouldn't be safe to have a non pinned LoadNode with
 194   // those inputs in the first place. If the graph already has a
 195   // pinned LoadNode and we add a non pinned LoadNode with the same
 196   // inputs, it's safe (but suboptimal) for GVN to replace the
 197   // non-pinned LoadNode by the pinned LoadNode.
 198   ControlDependency _control_dependency;
 199 
 200   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 201   // loads that can be reordered, and such requiring acquire semantics to
 202   // adhere to the Java specification.  The required behaviour is stored in
 203   // this field.
 204   const MemOrd _mo;
 205 
 206   AllocateNode* is_new_object_mark_load(PhaseGVN *phase) const;
 207 
 208 protected:
 209   virtual bool cmp(const Node &n) const;
 210   virtual uint size_of() const; // Size is bigger
 211   // Should LoadNode::Ideal() attempt to remove control edges?
 212   virtual bool can_remove_control() const;
 213   const Type* const _type;      // What kind of value is loaded?
 214 
 215   virtual Node* find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const;
 216 public:
 217 
 218   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo, ControlDependency control_dependency)
 219     : MemNode(c,mem,adr,at), _control_dependency(control_dependency), _mo(mo), _type(rt) {
 220     init_class_id(Class_Load);
 221   }
 222   inline bool is_unordered() const { return !is_acquire(); }
 223   inline bool is_acquire() const {
 224     assert(_mo == unordered || _mo == acquire, "unexpected");
 225     return _mo == acquire;
 226   }
 227   inline bool is_unsigned() const {
 228     int lop = Opcode();
 229     return (lop == Op_LoadUB) || (lop == Op_LoadUS);
 230   }
 231 
 232   // Polymorphic factory method:
 233   static Node* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
 234                     const TypePtr* at, const Type* rt, BasicType bt,
 235                     MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 236                     bool require_atomic_access = false, bool unaligned = false, bool mismatched = false, bool unsafe = false,
 237                     uint8_t barrier_data = 0);
 238 
 239   virtual uint hash()   const;  // Check the type
 240 
 241   // Handle algebraic identities here.  If we have an identity, return the Node
 242   // we are equivalent to.  We look for Load of a Store.
 243   virtual Node* Identity(PhaseGVN* phase);
 244 
 245   // If the load is from Field memory and the pointer is non-null, it might be possible to
 246   // zero out the control input.
 247   // If the offset is constant and the base is an object allocation,
 248   // try to hook me up to the exact initializing store.
 249   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 250 
 251   // Split instance field load through Phi.
 252   Node* split_through_phi(PhaseGVN *phase);
 253 
 254   // Recover original value from boxed values
 255   Node *eliminate_autobox(PhaseIterGVN *igvn);
 256 
 257   // Compute a new Type for this node.  Basically we just do the pre-check,
 258   // then call the virtual add() to set the type.
 259   virtual const Type* Value(PhaseGVN* phase) const;
 260 
 261   // Common methods for LoadKlass and LoadNKlass nodes.
 262   const Type* klass_value_common(PhaseGVN* phase) const;
 263   Node* klass_identity_common(PhaseGVN* phase);
 264 
 265   virtual uint ideal_reg() const;
 266   virtual const Type *bottom_type() const;
 267   // Following method is copied from TypeNode:
 268   void set_type(const Type* t) {
 269     assert(t != NULL, "sanity");
 270     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 271     *(const Type**)&_type = t;   // cast away const-ness
 272     // If this node is in the hash table, make sure it doesn't need a rehash.
 273     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 274   }
 275   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };
 276 
 277   // Do not match memory edge
 278   virtual uint match_edge(uint idx) const;
 279 
 280   // Map a load opcode to its corresponding store opcode.
 281   virtual int store_Opcode() const = 0;
 282 
 283   // Check if the load's memory input is a Phi node with the same control.
 284   bool is_instance_field_load_with_local_phi(Node* ctrl);
 285 
 286   Node* convert_to_unsigned_load(PhaseGVN& gvn);
 287   Node* convert_to_signed_load(PhaseGVN& gvn);
 288 
 289   bool  has_reinterpret_variant(const Type* rt);
 290   Node* convert_to_reinterpret_load(PhaseGVN& gvn, const Type* rt);
 291 
 292   ControlDependency control_dependency() {return _control_dependency; }
 293 
 294   bool has_unknown_control_dependency() const { return _control_dependency == UnknownControl; }
 295 
 296 #ifndef PRODUCT
 297   virtual void dump_spec(outputStream *st) const;
 298 #endif
 299 #ifdef ASSERT
 300   // Helper function to allow a raw load without control edge for some cases
 301   static bool is_immutable_value(Node* adr);
 302 #endif
 303 protected:
 304   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 305                                      ciKlass* klass) const;
 306 
 307   Node* can_see_arraycopy_value(Node* st, PhaseGVN* phase) const;
 308 
 309   // depends_only_on_test is almost always true, and needs to be almost always
 310   // true to enable key hoisting & commoning optimizations.  However, for the
 311   // special case of RawPtr loads from TLS top & end, and other loads performed by
 312   // GC barriers, the control edge carries the dependence preventing hoisting past
 313   // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
 314   // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
 315   // which produce results (new raw memory state) inside of loops preventing all
 316   // manner of other optimizations).  Basically, it's ugly but so is the alternative.
 317   // See comment in macro.cpp, around line 125 expand_allocate_common().
 318   virtual bool depends_only_on_test() const {
 319     return adr_type() != TypeRawPtr::BOTTOM && _control_dependency == DependsOnlyOnTest;
 320   }
 321 };
 322 
 323 //------------------------------LoadBNode--------------------------------------
 324 // Load a byte (8bits signed) from memory
 325 class LoadBNode : public LoadNode {
 326 public:
 327   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 328     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 329   virtual int Opcode() const;
 330   virtual uint ideal_reg() const { return Op_RegI; }
 331   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 332   virtual const Type* Value(PhaseGVN* phase) const;
 333   virtual int store_Opcode() const { return Op_StoreB; }
 334   virtual BasicType memory_type() const { return T_BYTE; }
 335 };
 336 
 337 //------------------------------LoadUBNode-------------------------------------
 338 // Load a unsigned byte (8bits unsigned) from memory
 339 class LoadUBNode : public LoadNode {
 340 public:
 341   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 342     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 343   virtual int Opcode() const;
 344   virtual uint ideal_reg() const { return Op_RegI; }
 345   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 346   virtual const Type* Value(PhaseGVN* phase) const;
 347   virtual int store_Opcode() const { return Op_StoreB; }
 348   virtual BasicType memory_type() const { return T_BYTE; }
 349 };
 350 
 351 //------------------------------LoadUSNode-------------------------------------
 352 // Load an unsigned short/char (16bits unsigned) from memory
 353 class LoadUSNode : public LoadNode {
 354 public:
 355   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 356     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 357   virtual int Opcode() const;
 358   virtual uint ideal_reg() const { return Op_RegI; }
 359   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 360   virtual const Type* Value(PhaseGVN* phase) const;
 361   virtual int store_Opcode() const { return Op_StoreC; }
 362   virtual BasicType memory_type() const { return T_CHAR; }
 363 };
 364 
 365 //------------------------------LoadSNode--------------------------------------
 366 // Load a short (16bits signed) from memory
 367 class LoadSNode : public LoadNode {
 368 public:
 369   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 370     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 371   virtual int Opcode() const;
 372   virtual uint ideal_reg() const { return Op_RegI; }
 373   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 374   virtual const Type* Value(PhaseGVN* phase) const;
 375   virtual int store_Opcode() const { return Op_StoreC; }
 376   virtual BasicType memory_type() const { return T_SHORT; }
 377 };
 378 
 379 //------------------------------LoadINode--------------------------------------
 380 // Load an integer from memory
 381 class LoadINode : public LoadNode {
 382 public:
 383   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 384     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 385   virtual int Opcode() const;
 386   virtual uint ideal_reg() const { return Op_RegI; }
 387   virtual int store_Opcode() const { return Op_StoreI; }
 388   virtual BasicType memory_type() const { return T_INT; }
 389 };
 390 
 391 //------------------------------LoadRangeNode----------------------------------
 392 // Load an array length from the array
 393 class LoadRangeNode : public LoadINode {
 394 public:
 395   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 396     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
 397   virtual int Opcode() const;
 398   virtual const Type* Value(PhaseGVN* phase) const;
 399   virtual Node* Identity(PhaseGVN* phase);
 400   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 401 };
 402 
 403 //------------------------------LoadLNode--------------------------------------
 404 // Load a long from memory
 405 class LoadLNode : public LoadNode {
 406   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 407   virtual bool cmp( const Node &n ) const {
 408     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 409       && LoadNode::cmp(n);
 410   }
 411   virtual uint size_of() const { return sizeof(*this); }
 412   const bool _require_atomic_access;  // is piecewise load forbidden?
 413 
 414 public:
 415   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 416             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 417     : LoadNode(c, mem, adr, at, tl, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 418   virtual int Opcode() const;
 419   virtual uint ideal_reg() const { return Op_RegL; }
 420   virtual int store_Opcode() const { return Op_StoreL; }
 421   virtual BasicType memory_type() const { return T_LONG; }
 422   bool require_atomic_access() const { return _require_atomic_access; }
 423 
 424 #ifndef PRODUCT
 425   virtual void dump_spec(outputStream *st) const {
 426     LoadNode::dump_spec(st);
 427     if (_require_atomic_access)  st->print(" Atomic!");
 428   }
 429 #endif
 430 };
 431 
 432 //------------------------------LoadL_unalignedNode----------------------------
 433 // Load a long from unaligned memory
 434 class LoadL_unalignedNode : public LoadLNode {
 435 public:
 436   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 437     : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo, control_dependency) {}
 438   virtual int Opcode() const;
 439 };
 440 
 441 //------------------------------LoadFNode--------------------------------------
 442 // Load a float (64 bits) from memory
 443 class LoadFNode : public LoadNode {
 444 public:
 445   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 446     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 447   virtual int Opcode() const;
 448   virtual uint ideal_reg() const { return Op_RegF; }
 449   virtual int store_Opcode() const { return Op_StoreF; }
 450   virtual BasicType memory_type() const { return T_FLOAT; }
 451 };
 452 
 453 //------------------------------LoadDNode--------------------------------------
 454 // Load a double (64 bits) from memory
 455 class LoadDNode : public LoadNode {
 456   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 457   virtual bool cmp( const Node &n ) const {
 458     return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
 459       && LoadNode::cmp(n);
 460   }
 461   virtual uint size_of() const { return sizeof(*this); }
 462   const bool _require_atomic_access;  // is piecewise load forbidden?
 463 
 464 public:
 465   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
 466             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 467     : LoadNode(c, mem, adr, at, t, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 468   virtual int Opcode() const;
 469   virtual uint ideal_reg() const { return Op_RegD; }
 470   virtual int store_Opcode() const { return Op_StoreD; }
 471   virtual BasicType memory_type() const { return T_DOUBLE; }
 472   bool require_atomic_access() const { return _require_atomic_access; }
 473 
 474 #ifndef PRODUCT
 475   virtual void dump_spec(outputStream *st) const {
 476     LoadNode::dump_spec(st);
 477     if (_require_atomic_access)  st->print(" Atomic!");
 478   }
 479 #endif
 480 };
 481 
 482 //------------------------------LoadD_unalignedNode----------------------------
 483 // Load a double from unaligned memory
 484 class LoadD_unalignedNode : public LoadDNode {
 485 public:
 486   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 487     : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo, control_dependency) {}
 488   virtual int Opcode() const;
 489 };
 490 
 491 //------------------------------LoadPNode--------------------------------------
 492 // Load a pointer from memory (either object or array)
 493 class LoadPNode : public LoadNode {
 494 public:
 495   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 496     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 497   virtual int Opcode() const;
 498   virtual uint ideal_reg() const { return Op_RegP; }
 499   virtual int store_Opcode() const { return Op_StoreP; }
 500   virtual BasicType memory_type() const { return T_ADDRESS; }
 501 };
 502 
 503 
 504 //------------------------------LoadNNode--------------------------------------
 505 // Load a narrow oop from memory (either object or array)
 506 class LoadNNode : public LoadNode {
 507 public:
 508   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 509     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 510   virtual int Opcode() const;
 511   virtual uint ideal_reg() const { return Op_RegN; }
 512   virtual int store_Opcode() const { return Op_StoreN; }
 513   virtual BasicType memory_type() const { return T_NARROWOOP; }
 514 };
 515 
 516 //------------------------------LoadKlassNode----------------------------------
 517 // Load a Klass from an object
 518 class LoadKlassNode : public LoadPNode {
 519 protected:
 520   // In most cases, LoadKlassNode does not have the control input set. If the control
 521   // input is set, it must not be removed (by LoadNode::Ideal()).
 522   virtual bool can_remove_control() const;
 523 public:
 524   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
 525     : LoadPNode(c, mem, adr, at, tk, mo) {}
 526   virtual int Opcode() const;
 527   virtual const Type* Value(PhaseGVN* phase) const;
 528   virtual Node* Identity(PhaseGVN* phase);
 529   virtual bool depends_only_on_test() const { return true; }
 530 
 531   // Polymorphic factory method:
 532   static Node* make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at,
 533                     const TypeKlassPtr* tk = TypeInstKlassPtr::OBJECT);
 534 };
 535 
 536 //------------------------------LoadNKlassNode---------------------------------
 537 // Load a narrow Klass from an object.
 538 class LoadNKlassNode : public LoadNNode {
 539 public:
 540   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, MemOrd mo)
 541     : LoadNNode(c, mem, adr, at, tk, mo) {}
 542   virtual int Opcode() const;
 543   virtual uint ideal_reg() const { return Op_RegN; }
 544   virtual int store_Opcode() const { return Op_StoreNKlass; }
 545   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 546 
 547   virtual const Type* Value(PhaseGVN* phase) const;
 548   virtual Node* Identity(PhaseGVN* phase);
 549   virtual bool depends_only_on_test() const { return true; }
 550 };
 551 
 552 //------------------------------StoreNode--------------------------------------
 553 // Store value; requires Store, Address and Value
 554 class StoreNode : public MemNode {
 555 private:
 556   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 557   // stores that can be reordered, and such requiring release semantics to
 558   // adhere to the Java specification.  The required behaviour is stored in
 559   // this field.
 560   const MemOrd _mo;
 561   // Needed for proper cloning.
 562   virtual uint size_of() const { return sizeof(*this); }
 563 protected:
 564   virtual bool cmp( const Node &n ) const;
 565   virtual bool depends_only_on_test() const { return false; }
 566 
 567   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 568   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 569 
 570 public:
 571   // We must ensure that stores of object references will be visible
 572   // only after the object's initialization. So the callers of this
 573   // procedure must indicate that the store requires `release'
 574   // semantics, if the stored value is an object reference that might
 575   // point to a new object and may become externally visible.
 576   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 577     : MemNode(c, mem, adr, at, val), _mo(mo) {
 578     init_class_id(Class_Store);
 579   }
 580   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 581     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 582     init_class_id(Class_Store);
 583   }
 584 
 585   inline bool is_unordered() const { return !is_release(); }
 586   inline bool is_release() const {
 587     assert((_mo == unordered || _mo == release), "unexpected");
 588     return _mo == release;
 589   }
 590 
 591   // Conservatively release stores of object references in order to
 592   // ensure visibility of object initialization.
 593   static inline MemOrd release_if_reference(const BasicType t) {
 594 #ifdef AARCH64
 595     // AArch64 doesn't need a release store here because object
 596     // initialization contains the necessary barriers.
 597     return unordered;
 598 #else
 599     const MemOrd mo = (t == T_ARRAY ||
 600                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 601                        t == T_OBJECT) ? release : unordered;
 602     return mo;
 603 #endif
 604   }
 605 
 606   // Polymorphic factory method
 607   //
 608   // We must ensure that stores of object references will be visible
 609   // only after the object's initialization. So the callers of this
 610   // procedure must indicate that the store requires `release'
 611   // semantics, if the stored value is an object reference that might
 612   // point to a new object and may become externally visible.
 613   static StoreNode* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
 614                          const TypePtr* at, Node* val, BasicType bt,
 615                          MemOrd mo, bool require_atomic_access = false);
 616 
 617   virtual uint hash() const;    // Check the type
 618 
 619   // If the store is to Field memory and the pointer is non-null, we can
 620   // zero out the control input.
 621   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 622 
 623   // Compute a new Type for this node.  Basically we just do the pre-check,
 624   // then call the virtual add() to set the type.
 625   virtual const Type* Value(PhaseGVN* phase) const;
 626 
 627   // Check for identity function on memory (Load then Store at same address)
 628   virtual Node* Identity(PhaseGVN* phase);
 629 
 630   // Do not match memory edge
 631   virtual uint match_edge(uint idx) const;
 632 
 633   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 634 
 635   // Map a store opcode to its corresponding own opcode, trivially.
 636   virtual int store_Opcode() const { return Opcode(); }
 637 
 638   // have all possible loads of the value stored been optimized away?
 639   bool value_never_loaded(PhaseTransform *phase) const;
 640 
 641   bool  has_reinterpret_variant(const Type* vt);
 642   Node* convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt);
 643 
 644   MemBarNode* trailing_membar() const;
 645 };
 646 
 647 //------------------------------StoreBNode-------------------------------------
 648 // Store byte to memory
 649 class StoreBNode : public StoreNode {
 650 public:
 651   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 652     : StoreNode(c, mem, adr, at, val, mo) {}
 653   virtual int Opcode() const;
 654   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 655   virtual BasicType memory_type() const { return T_BYTE; }
 656 };
 657 
 658 //------------------------------StoreCNode-------------------------------------
 659 // Store char/short to memory
 660 class StoreCNode : public StoreNode {
 661 public:
 662   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 663     : StoreNode(c, mem, adr, at, val, mo) {}
 664   virtual int Opcode() const;
 665   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 666   virtual BasicType memory_type() const { return T_CHAR; }
 667 };
 668 
 669 //------------------------------StoreINode-------------------------------------
 670 // Store int to memory
 671 class StoreINode : public StoreNode {
 672 public:
 673   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 674     : StoreNode(c, mem, adr, at, val, mo) {}
 675   virtual int Opcode() const;
 676   virtual BasicType memory_type() const { return T_INT; }
 677 };
 678 
 679 //------------------------------StoreLNode-------------------------------------
 680 // Store long to memory
 681 class StoreLNode : public StoreNode {
 682   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 683   virtual bool cmp( const Node &n ) const {
 684     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 685       && StoreNode::cmp(n);
 686   }
 687   virtual uint size_of() const { return sizeof(*this); }
 688   const bool _require_atomic_access;  // is piecewise store forbidden?
 689 
 690 public:
 691   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 692     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 693   virtual int Opcode() const;
 694   virtual BasicType memory_type() const { return T_LONG; }
 695   bool require_atomic_access() const { return _require_atomic_access; }
 696 
 697 #ifndef PRODUCT
 698   virtual void dump_spec(outputStream *st) const {
 699     StoreNode::dump_spec(st);
 700     if (_require_atomic_access)  st->print(" Atomic!");
 701   }
 702 #endif
 703 };
 704 
 705 //------------------------------StoreFNode-------------------------------------
 706 // Store float to memory
 707 class StoreFNode : public StoreNode {
 708 public:
 709   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 710     : StoreNode(c, mem, adr, at, val, mo) {}
 711   virtual int Opcode() const;
 712   virtual BasicType memory_type() const { return T_FLOAT; }
 713 };
 714 
 715 //------------------------------StoreDNode-------------------------------------
 716 // Store double to memory
 717 class StoreDNode : public StoreNode {
 718   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 719   virtual bool cmp( const Node &n ) const {
 720     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 721       && StoreNode::cmp(n);
 722   }
 723   virtual uint size_of() const { return sizeof(*this); }
 724   const bool _require_atomic_access;  // is piecewise store forbidden?
 725 public:
 726   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 727              MemOrd mo, bool require_atomic_access = false)
 728     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 729   virtual int Opcode() const;
 730   virtual BasicType memory_type() const { return T_DOUBLE; }
 731   bool require_atomic_access() const { return _require_atomic_access; }
 732 
 733 #ifndef PRODUCT
 734   virtual void dump_spec(outputStream *st) const {
 735     StoreNode::dump_spec(st);
 736     if (_require_atomic_access)  st->print(" Atomic!");
 737   }
 738 #endif
 739 
 740 };
 741 
 742 //------------------------------StorePNode-------------------------------------
 743 // Store pointer to memory
 744 class StorePNode : public StoreNode {
 745 public:
 746   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 747     : StoreNode(c, mem, adr, at, val, mo) {}
 748   virtual int Opcode() const;
 749   virtual BasicType memory_type() const { return T_ADDRESS; }
 750 };
 751 
 752 //------------------------------StoreNNode-------------------------------------
 753 // Store narrow oop to memory
 754 class StoreNNode : public StoreNode {
 755 public:
 756   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 757     : StoreNode(c, mem, adr, at, val, mo) {}
 758   virtual int Opcode() const;
 759   virtual BasicType memory_type() const { return T_NARROWOOP; }
 760 };
 761 
 762 //------------------------------StoreNKlassNode--------------------------------------
 763 // Store narrow klass to memory
 764 class StoreNKlassNode : public StoreNNode {
 765 public:
 766   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 767     : StoreNNode(c, mem, adr, at, val, mo) {}
 768   virtual int Opcode() const;
 769   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 770 };
 771 
 772 //------------------------------StoreCMNode-----------------------------------
 773 // Store card-mark byte to memory for CM
 774 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store
 775 // Preceding equivalent StoreCMs may be eliminated.
 776 class StoreCMNode : public StoreNode {
 777  private:
 778   virtual uint hash() const { return StoreNode::hash() + _oop_alias_idx; }
 779   virtual bool cmp( const Node &n ) const {
 780     return _oop_alias_idx == ((StoreCMNode&)n)._oop_alias_idx
 781       && StoreNode::cmp(n);
 782   }
 783   virtual uint size_of() const { return sizeof(*this); }
 784   int _oop_alias_idx;   // The alias_idx of OopStore
 785 
 786 public:
 787   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, int oop_alias_idx ) :
 788     StoreNode(c, mem, adr, at, val, oop_store, MemNode::release),
 789     _oop_alias_idx(oop_alias_idx) {
 790     assert(_oop_alias_idx >= Compile::AliasIdxRaw ||
 791            _oop_alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
 792            "bad oop alias idx");
 793   }
 794   virtual int Opcode() const;
 795   virtual Node* Identity(PhaseGVN* phase);
 796   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 797   virtual const Type* Value(PhaseGVN* phase) const;
 798   virtual BasicType memory_type() const { return T_VOID; } // unspecific
 799   int oop_alias_idx() const { return _oop_alias_idx; }
 800 };
 801 
 802 //------------------------------SCMemProjNode---------------------------------------
 803 // This class defines a projection of the memory  state of a store conditional node.
 804 // These nodes return a value, but also update memory.
 805 class SCMemProjNode : public ProjNode {
 806 public:
 807   enum {SCMEMPROJCON = (uint)-2};
 808   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 809   virtual int Opcode() const;
 810   virtual bool      is_CFG() const  { return false; }
 811   virtual const Type *bottom_type() const {return Type::MEMORY;}
 812   virtual const TypePtr *adr_type() const {
 813     Node* ctrl = in(0);
 814     if (ctrl == NULL)  return NULL; // node is dead
 815     return ctrl->in(MemNode::Memory)->adr_type();
 816   }
 817   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 818   virtual const Type* Value(PhaseGVN* phase) const;
 819 #ifndef PRODUCT
 820   virtual void dump_spec(outputStream *st) const {};
 821 #endif
 822 };
 823 
 824 //------------------------------LoadStoreNode---------------------------
 825 // Note: is_Mem() method returns 'true' for this class.
 826 class LoadStoreNode : public Node {
 827 private:
 828   const Type* const _type;      // What kind of value is loaded?
 829   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 830   uint8_t _barrier_data;        // Bit field with barrier information
 831   virtual uint size_of() const; // Size is bigger
 832 public:
 833   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 834   virtual bool depends_only_on_test() const { return false; }
 835   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 836 
 837   virtual const Type *bottom_type() const { return _type; }
 838   virtual uint ideal_reg() const;
 839   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 840   virtual const Type* Value(PhaseGVN* phase) const;
 841 
 842   bool result_not_used() const;
 843   MemBarNode* trailing_membar() const;
 844 
 845   uint8_t barrier_data() { return _barrier_data; }
 846   void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
 847 };
 848 
 849 class LoadStoreConditionalNode : public LoadStoreNode {
 850 public:
 851   enum {
 852     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 853   };
 854   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 855   virtual const Type* Value(PhaseGVN* phase) const;
 856 };
 857 
 858 class CompareAndSwapNode : public LoadStoreConditionalNode {
 859 private:
 860   const MemNode::MemOrd _mem_ord;
 861 public:
 862   CompareAndSwapNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : LoadStoreConditionalNode(c, mem, adr, val, ex), _mem_ord(mem_ord) {}
 863   MemNode::MemOrd order() const {
 864     return _mem_ord;
 865   }
 866   virtual uint size_of() const { return sizeof(*this); }
 867 };
 868 
 869 class CompareAndExchangeNode : public LoadStoreNode {
 870 private:
 871   const MemNode::MemOrd _mem_ord;
 872 public:
 873   enum {
 874     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 875   };
 876   CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
 877     LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
 878      init_req(ExpectedIn, ex );
 879   }
 880 
 881   MemNode::MemOrd order() const {
 882     return _mem_ord;
 883   }
 884   virtual uint size_of() const { return sizeof(*this); }
 885 };
 886 
 887 //------------------------------CompareAndSwapBNode---------------------------
 888 class CompareAndSwapBNode : public CompareAndSwapNode {
 889 public:
 890   CompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 891   virtual int Opcode() const;
 892 };
 893 
 894 //------------------------------CompareAndSwapSNode---------------------------
 895 class CompareAndSwapSNode : public CompareAndSwapNode {
 896 public:
 897   CompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 898   virtual int Opcode() const;
 899 };
 900 
 901 //------------------------------CompareAndSwapINode---------------------------
 902 class CompareAndSwapINode : public CompareAndSwapNode {
 903 public:
 904   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 905   virtual int Opcode() const;
 906 };
 907 
 908 //------------------------------CompareAndSwapLNode---------------------------
 909 class CompareAndSwapLNode : public CompareAndSwapNode {
 910 public:
 911   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 912   virtual int Opcode() const;
 913 };
 914 
 915 //------------------------------CompareAndSwapPNode---------------------------
 916 class CompareAndSwapPNode : public CompareAndSwapNode {
 917 public:
 918   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 919   virtual int Opcode() const;
 920 };
 921 
 922 //------------------------------CompareAndSwapNNode---------------------------
 923 class CompareAndSwapNNode : public CompareAndSwapNode {
 924 public:
 925   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 926   virtual int Opcode() const;
 927 };
 928 
 929 //------------------------------WeakCompareAndSwapBNode---------------------------
 930 class WeakCompareAndSwapBNode : public CompareAndSwapNode {
 931 public:
 932   WeakCompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 933   virtual int Opcode() const;
 934 };
 935 
 936 //------------------------------WeakCompareAndSwapSNode---------------------------
 937 class WeakCompareAndSwapSNode : public CompareAndSwapNode {
 938 public:
 939   WeakCompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 940   virtual int Opcode() const;
 941 };
 942 
 943 //------------------------------WeakCompareAndSwapINode---------------------------
 944 class WeakCompareAndSwapINode : public CompareAndSwapNode {
 945 public:
 946   WeakCompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 947   virtual int Opcode() const;
 948 };
 949 
 950 //------------------------------WeakCompareAndSwapLNode---------------------------
 951 class WeakCompareAndSwapLNode : public CompareAndSwapNode {
 952 public:
 953   WeakCompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 954   virtual int Opcode() const;
 955 };
 956 
 957 //------------------------------WeakCompareAndSwapPNode---------------------------
 958 class WeakCompareAndSwapPNode : public CompareAndSwapNode {
 959 public:
 960   WeakCompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 961   virtual int Opcode() const;
 962 };
 963 
 964 //------------------------------WeakCompareAndSwapNNode---------------------------
 965 class WeakCompareAndSwapNNode : public CompareAndSwapNode {
 966 public:
 967   WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 968   virtual int Opcode() const;
 969 };
 970 
 971 //------------------------------CompareAndExchangeBNode---------------------------
 972 class CompareAndExchangeBNode : public CompareAndExchangeNode {
 973 public:
 974   CompareAndExchangeBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::BYTE) { }
 975   virtual int Opcode() const;
 976 };
 977 
 978 
 979 //------------------------------CompareAndExchangeSNode---------------------------
 980 class CompareAndExchangeSNode : public CompareAndExchangeNode {
 981 public:
 982   CompareAndExchangeSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::SHORT) { }
 983   virtual int Opcode() const;
 984 };
 985 
 986 //------------------------------CompareAndExchangeLNode---------------------------
 987 class CompareAndExchangeLNode : public CompareAndExchangeNode {
 988 public:
 989   CompareAndExchangeLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeLong::LONG) { }
 990   virtual int Opcode() const;
 991 };
 992 
 993 
 994 //------------------------------CompareAndExchangeINode---------------------------
 995 class CompareAndExchangeINode : public CompareAndExchangeNode {
 996 public:
 997   CompareAndExchangeINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::INT) { }
 998   virtual int Opcode() const;
 999 };
1000 
1001 
1002 //------------------------------CompareAndExchangePNode---------------------------
1003 class CompareAndExchangePNode : public CompareAndExchangeNode {
1004 public:
1005   CompareAndExchangePNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
1006   virtual int Opcode() const;
1007 };
1008 
1009 //------------------------------CompareAndExchangeNNode---------------------------
1010 class CompareAndExchangeNNode : public CompareAndExchangeNode {
1011 public:
1012   CompareAndExchangeNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
1013   virtual int Opcode() const;
1014 };
1015 
1016 //------------------------------GetAndAddBNode---------------------------
1017 class GetAndAddBNode : public LoadStoreNode {
1018 public:
1019   GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1020   virtual int Opcode() const;
1021 };
1022 
1023 //------------------------------GetAndAddSNode---------------------------
1024 class GetAndAddSNode : public LoadStoreNode {
1025 public:
1026   GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1027   virtual int Opcode() const;
1028 };
1029 
1030 //------------------------------GetAndAddINode---------------------------
1031 class GetAndAddINode : public LoadStoreNode {
1032 public:
1033   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1034   virtual int Opcode() const;
1035 };
1036 
1037 //------------------------------GetAndAddLNode---------------------------
1038 class GetAndAddLNode : public LoadStoreNode {
1039 public:
1040   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1041   virtual int Opcode() const;
1042 };
1043 
1044 //------------------------------GetAndSetBNode---------------------------
1045 class GetAndSetBNode : public LoadStoreNode {
1046 public:
1047   GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1048   virtual int Opcode() const;
1049 };
1050 
1051 //------------------------------GetAndSetSNode---------------------------
1052 class GetAndSetSNode : public LoadStoreNode {
1053 public:
1054   GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1055   virtual int Opcode() const;
1056 };
1057 
1058 //------------------------------GetAndSetINode---------------------------
1059 class GetAndSetINode : public LoadStoreNode {
1060 public:
1061   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1062   virtual int Opcode() const;
1063 };
1064 
1065 //------------------------------GetAndSetLNode---------------------------
1066 class GetAndSetLNode : public LoadStoreNode {
1067 public:
1068   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1069   virtual int Opcode() const;
1070 };
1071 
1072 //------------------------------GetAndSetPNode---------------------------
1073 class GetAndSetPNode : public LoadStoreNode {
1074 public:
1075   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1076   virtual int Opcode() const;
1077 };
1078 
1079 //------------------------------GetAndSetNNode---------------------------
1080 class GetAndSetNNode : public LoadStoreNode {
1081 public:
1082   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1083   virtual int Opcode() const;
1084 };
1085 
1086 //------------------------------ClearArray-------------------------------------
1087 class ClearArrayNode: public Node {
1088 private:
1089   bool _is_large;
1090   bool _word_copy_only;
1091 public:
1092   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, Node* val, bool is_large)
1093     : Node(ctrl, arymem, word_cnt, base, val), _is_large(is_large),
1094       _word_copy_only(val->bottom_type()->isa_long() && (!val->bottom_type()->is_long()->is_con() || val->bottom_type()->is_long()->get_con() != 0)) {
1095     init_class_id(Class_ClearArray);
1096   }
1097   virtual int         Opcode() const;
1098   virtual const Type *bottom_type() const { return Type::MEMORY; }
1099   // ClearArray modifies array elements, and so affects only the
1100   // array memory addressed by the bottom_type of its base address.
1101   virtual const class TypePtr *adr_type() const;
1102   virtual Node* Identity(PhaseGVN* phase);
1103   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1104   virtual uint match_edge(uint idx) const;
1105   bool is_large() const { return _is_large; }
1106   bool word_copy_only() const { return _word_copy_only; }
1107 
1108   // Clear the given area of an object or array.
1109   // The start offset must always be aligned mod BytesPerInt.
1110   // The end offset must always be aligned mod BytesPerLong.
1111   // Return the new memory.
1112   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1113                             Node* val,
1114                             Node* raw_val,
1115                             intptr_t start_offset,
1116                             intptr_t end_offset,
1117                             PhaseGVN* phase);
1118   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1119                             Node* val,
1120                             Node* raw_val,
1121                             intptr_t start_offset,
1122                             Node* end_offset,
1123                             PhaseGVN* phase);
1124   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1125                             Node* raw_val,
1126                             Node* start_offset,
1127                             Node* end_offset,
1128                             PhaseGVN* phase);
1129   // Return allocation input memory edge if it is different instance
1130   // or itself if it is the one we are looking for.
1131   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
1132 };
1133 
1134 //------------------------------MemBar-----------------------------------------
1135 // There are different flavors of Memory Barriers to match the Java Memory
1136 // Model.  Monitor-enter and volatile-load act as Acquires: no following ref
1137 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
1138 // volatile-load.  Monitor-exit and volatile-store act as Release: no
1139 // preceding ref can be moved to after them.  We insert a MemBar-Release
1140 // before a FastUnlock or volatile-store.  All volatiles need to be
1141 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
1142 // separate it from any following volatile-load.
1143 class MemBarNode: public MultiNode {
1144   virtual uint hash() const ;                  // { return NO_HASH; }
1145   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1146 
1147   virtual uint size_of() const { return sizeof(*this); }
1148   // Memory type this node is serializing.  Usually either rawptr or bottom.
1149   const TypePtr* _adr_type;
1150 
1151   // How is this membar related to a nearby memory access?
1152   enum {
1153     Standalone,
1154     TrailingLoad,
1155     TrailingStore,
1156     LeadingStore,
1157     TrailingLoadStore,
1158     LeadingLoadStore,
1159     TrailingPartialArrayCopy
1160   } _kind;
1161 
1162 #ifdef ASSERT
1163   uint _pair_idx;
1164 #endif
1165 
1166 public:
1167   enum {
1168     Precedent = TypeFunc::Parms  // optional edge to force precedence
1169   };
1170   MemBarNode(Compile* C, int alias_idx, Node* precedent);
1171   virtual int Opcode() const = 0;
1172   virtual const class TypePtr *adr_type() const { return _adr_type; }
1173   virtual const Type* Value(PhaseGVN* phase) const;
1174   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1175   virtual uint match_edge(uint idx) const { return 0; }
1176   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
1177   virtual Node *match(const ProjNode *proj, const Matcher *m, const RegMask* mask);
1178   // Factory method.  Builds a wide or narrow membar.
1179   // Optional 'precedent' becomes an extra edge if not null.
1180   static MemBarNode* make(Compile* C, int opcode,
1181                           int alias_idx = Compile::AliasIdxBot,
1182                           Node* precedent = NULL);
1183 
1184   MemBarNode* trailing_membar() const;
1185   MemBarNode* leading_membar() const;
1186 
1187   void set_trailing_load() { _kind = TrailingLoad; }
1188   bool trailing_load() const { return _kind == TrailingLoad; }
1189   bool trailing_store() const { return _kind == TrailingStore; }
1190   bool leading_store() const { return _kind == LeadingStore; }
1191   bool trailing_load_store() const { return _kind == TrailingLoadStore; }
1192   bool leading_load_store() const { return _kind == LeadingLoadStore; }
1193   bool trailing() const { return _kind == TrailingLoad || _kind == TrailingStore || _kind == TrailingLoadStore; }
1194   bool leading() const { return _kind == LeadingStore || _kind == LeadingLoadStore; }
1195   bool standalone() const { return _kind == Standalone; }
1196   void set_trailing_partial_array_copy() { _kind = TrailingPartialArrayCopy; }
1197   bool trailing_partial_array_copy() const { return _kind == TrailingPartialArrayCopy; }
1198 
1199   static void set_store_pair(MemBarNode* leading, MemBarNode* trailing);
1200   static void set_load_store_pair(MemBarNode* leading, MemBarNode* trailing);
1201 
1202   void remove(PhaseIterGVN *igvn);
1203 };
1204 
1205 // "Acquire" - no following ref can move before (but earlier refs can
1206 // follow, like an early Load stalled in cache).  Requires multi-cpu
1207 // visibility.  Inserted after a volatile load.
1208 class MemBarAcquireNode: public MemBarNode {
1209 public:
1210   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1211     : MemBarNode(C, alias_idx, precedent) {}
1212   virtual int Opcode() const;
1213 };
1214 
1215 // "Acquire" - no following ref can move before (but earlier refs can
1216 // follow, like an early Load stalled in cache).  Requires multi-cpu
1217 // visibility.  Inserted independent of any load, as required
1218 // for intrinsic Unsafe.loadFence().
1219 class LoadFenceNode: public MemBarNode {
1220 public:
1221   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
1222     : MemBarNode(C, alias_idx, precedent) {}
1223   virtual int Opcode() const;
1224 };
1225 
1226 // "Release" - no earlier ref can move after (but later refs can move
1227 // up, like a speculative pipelined cache-hitting Load).  Requires
1228 // multi-cpu visibility.  Inserted before a volatile store.
1229 class MemBarReleaseNode: public MemBarNode {
1230 public:
1231   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1232     : MemBarNode(C, alias_idx, precedent) {}
1233   virtual int Opcode() const;
1234 };
1235 
1236 // "Release" - no earlier ref can move after (but later refs can move
1237 // up, like a speculative pipelined cache-hitting Load).  Requires
1238 // multi-cpu visibility.  Inserted independent of any store, as required
1239 // for intrinsic Unsafe.storeFence().
1240 class StoreFenceNode: public MemBarNode {
1241 public:
1242   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1243     : MemBarNode(C, alias_idx, precedent) {}
1244   virtual int Opcode() const;
1245 };
1246 
1247 // "Acquire" - no following ref can move before (but earlier refs can
1248 // follow, like an early Load stalled in cache).  Requires multi-cpu
1249 // visibility.  Inserted after a FastLock.
1250 class MemBarAcquireLockNode: public MemBarNode {
1251 public:
1252   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1253     : MemBarNode(C, alias_idx, precedent) {}
1254   virtual int Opcode() const;
1255 };
1256 
1257 // "Release" - no earlier ref can move after (but later refs can move
1258 // up, like a speculative pipelined cache-hitting Load).  Requires
1259 // multi-cpu visibility.  Inserted before a FastUnLock.
1260 class MemBarReleaseLockNode: public MemBarNode {
1261 public:
1262   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1263     : MemBarNode(C, alias_idx, precedent) {}
1264   virtual int Opcode() const;
1265 };
1266 
1267 class MemBarStoreStoreNode: public MemBarNode {
1268 public:
1269   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1270     : MemBarNode(C, alias_idx, precedent) {
1271     init_class_id(Class_MemBarStoreStore);
1272   }
1273   virtual int Opcode() const;
1274 };
1275 
1276 class StoreStoreFenceNode: public MemBarNode {
1277 public:
1278   StoreStoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1279     : MemBarNode(C, alias_idx, precedent) {}
1280   virtual int Opcode() const;
1281 };
1282 
1283 // Ordering between a volatile store and a following volatile load.
1284 // Requires multi-CPU visibility?
1285 class MemBarVolatileNode: public MemBarNode {
1286 public:
1287   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1288     : MemBarNode(C, alias_idx, precedent) {}
1289   virtual int Opcode() const;
1290 };
1291 
1292 // Ordering within the same CPU.  Used to order unsafe memory references
1293 // inside the compiler when we lack alias info.  Not needed "outside" the
1294 // compiler because the CPU does all the ordering for us.
1295 class MemBarCPUOrderNode: public MemBarNode {
1296 public:
1297   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1298     : MemBarNode(C, alias_idx, precedent) {}
1299   virtual int Opcode() const;
1300   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1301 };
1302 
1303 class OnSpinWaitNode: public MemBarNode {
1304 public:
1305   OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
1306     : MemBarNode(C, alias_idx, precedent) {}
1307   virtual int Opcode() const;
1308 };
1309 
1310 //------------------------------BlackholeNode----------------------------
1311 // Blackhole all arguments. This node would survive through the compiler
1312 // the effects on its arguments, and would be finally matched to nothing.
1313 class BlackholeNode : public MemBarNode {
1314 public:
1315   BlackholeNode(Compile* C, int alias_idx, Node* precedent)
1316     : MemBarNode(C, alias_idx, precedent) {
1317     init_class_id(Class_Blackhole);
1318   }
1319   virtual int   Opcode() const;
1320   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1321   const RegMask &in_RegMask(uint idx) const {
1322     // Fake the incoming arguments mask for blackholes: accept all registers
1323     // and all stack slots. This would avoid any redundant register moves
1324     // for blackhole inputs.
1325     return RegMask::All;
1326   }
1327 #ifndef PRODUCT
1328   virtual void format(PhaseRegAlloc* ra, outputStream* st) const;
1329 #endif
1330 };
1331 
1332 // Isolation of object setup after an AllocateNode and before next safepoint.
1333 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1334 class InitializeNode: public MemBarNode {
1335   friend class AllocateNode;
1336 
1337   enum {
1338     Incomplete    = 0,
1339     Complete      = 1,
1340     WithArraycopy = 2
1341   };
1342   int _is_complete;
1343 
1344   bool _does_not_escape;
1345 
1346 public:
1347   enum {
1348     Control    = TypeFunc::Control,
1349     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1350     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1351     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1352   };
1353 
1354   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1355   virtual int Opcode() const;
1356   virtual uint size_of() const { return sizeof(*this); }
1357   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1358   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1359 
1360   // Manage incoming memory edges via a MergeMem on in(Memory):
1361   Node* memory(uint alias_idx);
1362 
1363   // The raw memory edge coming directly from the Allocation.
1364   // The contents of this memory are *always* all-zero-bits.
1365   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1366 
1367   // Return the corresponding allocation for this initialization (or null if none).
1368   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1369   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1370   AllocateNode* allocation();
1371 
1372   // Anything other than zeroing in this init?
1373   bool is_non_zero();
1374 
1375   // An InitializeNode must completed before macro expansion is done.
1376   // Completion requires that the AllocateNode must be followed by
1377   // initialization of the new memory to zero, then to any initializers.
1378   bool is_complete() { return _is_complete != Incomplete; }
1379   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1380 
1381   // Mark complete.  (Must not yet be complete.)
1382   void set_complete(PhaseGVN* phase);
1383   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1384 
1385   bool does_not_escape() { return _does_not_escape; }
1386   void set_does_not_escape() { _does_not_escape = true; }
1387 
1388 #ifdef ASSERT
1389   // ensure all non-degenerate stores are ordered and non-overlapping
1390   bool stores_are_sane(PhaseTransform* phase);
1391 #endif //ASSERT
1392 
1393   // See if this store can be captured; return offset where it initializes.
1394   // Return 0 if the store cannot be moved (any sort of problem).
1395   intptr_t can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape);
1396 
1397   // Capture another store; reformat it to write my internal raw memory.
1398   // Return the captured copy, else NULL if there is some sort of problem.
1399   Node* capture_store(StoreNode* st, intptr_t start, PhaseGVN* phase, bool can_reshape);
1400 
1401   // Find captured store which corresponds to the range [start..start+size).
1402   // Return my own memory projection (meaning the initial zero bits)
1403   // if there is no such store.  Return NULL if there is a problem.
1404   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);
1405 
1406   // Called when the associated AllocateNode is expanded into CFG.
1407   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1408                         intptr_t header_size, Node* size_in_bytes,
1409                         PhaseIterGVN* phase);
1410 
1411  private:
1412   void remove_extra_zeroes();
1413 
1414   // Find out where a captured store should be placed (or already is placed).
1415   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1416                                      PhaseTransform* phase);
1417 
1418   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);
1419 
1420   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);
1421 
1422   bool detect_init_independence(Node* value, PhaseGVN* phase);
1423 
1424   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1425                                PhaseGVN* phase);
1426 
1427   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1428 };
1429 
1430 //------------------------------MergeMem---------------------------------------
1431 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1432 class MergeMemNode: public Node {
1433   virtual uint hash() const ;                  // { return NO_HASH; }
1434   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1435   friend class MergeMemStream;
1436   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1437 
1438 public:
1439   // If the input is a whole memory state, clone it with all its slices intact.
1440   // Otherwise, make a new memory state with just that base memory input.
1441   // In either case, the result is a newly created MergeMem.
1442   static MergeMemNode* make(Node* base_memory);
1443 
1444   virtual int Opcode() const;
1445   virtual Node* Identity(PhaseGVN* phase);
1446   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1447   virtual uint ideal_reg() const { return NotAMachineReg; }
1448   virtual uint match_edge(uint idx) const { return 0; }
1449   virtual const RegMask &out_RegMask() const;
1450   virtual const Type *bottom_type() const { return Type::MEMORY; }
1451   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1452   // sparse accessors
1453   // Fetch the previously stored "set_memory_at", or else the base memory.
1454   // (Caller should clone it if it is a phi-nest.)
1455   Node* memory_at(uint alias_idx) const;
1456   // set the memory, regardless of its previous value
1457   void set_memory_at(uint alias_idx, Node* n);
1458   // the "base" is the memory that provides the non-finite support
1459   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1460   // warning: setting the base can implicitly set any of the other slices too
1461   void set_base_memory(Node* def);
1462   // sentinel value which denotes a copy of the base memory:
1463   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1464   static Node* make_empty_memory(); // where the sentinel comes from
1465   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1466   // hook for the iterator, to perform any necessary setup
1467   void iteration_setup(const MergeMemNode* other = NULL);
1468   // push sentinels until I am at least as long as the other (semantic no-op)
1469   void grow_to_match(const MergeMemNode* other);
1470   bool verify_sparse() const PRODUCT_RETURN0;
1471 #ifndef PRODUCT
1472   virtual void dump_spec(outputStream *st) const;
1473 #endif
1474 };
1475 
1476 class MergeMemStream : public StackObj {
1477  private:
1478   MergeMemNode*       _mm;
1479   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1480   Node*               _mm_base;  // loop-invariant base memory of _mm
1481   int                 _idx;
1482   int                 _cnt;
1483   Node*               _mem;
1484   Node*               _mem2;
1485   int                 _cnt2;
1486 
1487   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {
1488     // subsume_node will break sparseness at times, whenever a memory slice
1489     // folds down to a copy of the base ("fat") memory.  In such a case,
1490     // the raw edge will update to base, although it should be top.
1491     // This iterator will recognize either top or base_memory as an
1492     // "empty" slice.  See is_empty, is_empty2, and next below.
1493     //
1494     // The sparseness property is repaired in MergeMemNode::Ideal.
1495     // As long as access to a MergeMem goes through this iterator
1496     // or the memory_at accessor, flaws in the sparseness will
1497     // never be observed.
1498     //
1499     // Also, iteration_setup repairs sparseness.
1500     assert(mm->verify_sparse(), "please, no dups of base");
1501     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");
1502 
1503     _mm  = mm;
1504     _mm_base = mm->base_memory();
1505     _mm2 = mm2;
1506     _cnt = mm->req();
1507     _idx = Compile::AliasIdxBot-1; // start at the base memory
1508     _mem = NULL;
1509     _mem2 = NULL;
1510   }
1511 
1512 #ifdef ASSERT
1513   Node* check_memory() const {
1514     if (at_base_memory())
1515       return _mm->base_memory();
1516     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1517       return _mm->memory_at(_idx);
1518     else
1519       return _mm_base;
1520   }
1521   Node* check_memory2() const {
1522     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1523   }
1524 #endif
1525 
1526   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1527   void assert_synch() const {
1528     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1529            "no side-effects except through the stream");
1530   }
1531 
1532  public:
1533 
1534   // expected usages:
1535   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1536   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1537 
1538   // iterate over one merge
1539   MergeMemStream(MergeMemNode* mm) {
1540     mm->iteration_setup();
1541     init(mm);
1542     debug_only(_cnt2 = 999);
1543   }
1544   // iterate in parallel over two merges
1545   // only iterates through non-empty elements of mm2
1546   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1547     assert(mm2, "second argument must be a MergeMem also");
1548     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1549     mm->iteration_setup(mm2);
1550     init(mm, mm2);
1551     _cnt2 = mm2->req();
1552   }
1553 #ifdef ASSERT
1554   ~MergeMemStream() {
1555     assert_synch();
1556   }
1557 #endif
1558 
1559   MergeMemNode* all_memory() const {
1560     return _mm;
1561   }
1562   Node* base_memory() const {
1563     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1564     return _mm_base;
1565   }
1566   const MergeMemNode* all_memory2() const {
1567     assert(_mm2 != NULL, "");
1568     return _mm2;
1569   }
1570   bool at_base_memory() const {
1571     return _idx == Compile::AliasIdxBot;
1572   }
1573   int alias_idx() const {
1574     assert(_mem, "must call next 1st");
1575     return _idx;
1576   }
1577 
1578   const TypePtr* adr_type() const {
1579     return Compile::current()->get_adr_type(alias_idx());
1580   }
1581 
1582   const TypePtr* adr_type(Compile* C) const {
1583     return C->get_adr_type(alias_idx());
1584   }
1585   bool is_empty() const {
1586     assert(_mem, "must call next 1st");
1587     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1588     return _mem->is_top();
1589   }
1590   bool is_empty2() const {
1591     assert(_mem2, "must call next 1st");
1592     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1593     return _mem2->is_top();
1594   }
1595   Node* memory() const {
1596     assert(!is_empty(), "must not be empty");
1597     assert_synch();
1598     return _mem;
1599   }
1600   // get the current memory, regardless of empty or non-empty status
1601   Node* force_memory() const {
1602     assert(!is_empty() || !at_base_memory(), "");
1603     // Use _mm_base to defend against updates to _mem->base_memory().
1604     Node *mem = _mem->is_top() ? _mm_base : _mem;
1605     assert(mem == check_memory(), "");
1606     return mem;
1607   }
1608   Node* memory2() const {
1609     assert(_mem2 == check_memory2(), "");
1610     return _mem2;
1611   }
1612   void set_memory(Node* mem) {
1613     if (at_base_memory()) {
1614       // Note that this does not change the invariant _mm_base.
1615       _mm->set_base_memory(mem);
1616     } else {
1617       _mm->set_memory_at(_idx, mem);
1618     }
1619     _mem = mem;
1620     assert_synch();
1621   }
1622 
1623   // Recover from a side effect to the MergeMemNode.
1624   void set_memory() {
1625     _mem = _mm->in(_idx);
1626   }
1627 
1628   bool next()  { return next(false); }
1629   bool next2() { return next(true); }
1630 
1631   bool next_non_empty()  { return next_non_empty(false); }
1632   bool next_non_empty2() { return next_non_empty(true); }
1633   // next_non_empty2 can yield states where is_empty() is true
1634 
1635  private:
1636   // find the next item, which might be empty
1637   bool next(bool have_mm2) {
1638     assert((_mm2 != NULL) == have_mm2, "use other next");
1639     assert_synch();
1640     if (++_idx < _cnt) {
1641       // Note:  This iterator allows _mm to be non-sparse.
1642       // It behaves the same whether _mem is top or base_memory.
1643       _mem = _mm->in(_idx);
1644       if (have_mm2)
1645         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1646       return true;
1647     }
1648     return false;
1649   }
1650 
1651   // find the next non-empty item
1652   bool next_non_empty(bool have_mm2) {
1653     while (next(have_mm2)) {
1654       if (!is_empty()) {
1655         // make sure _mem2 is filled in sensibly
1656         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1657         return true;
1658       } else if (have_mm2 && !is_empty2()) {
1659         return true;   // is_empty() == true
1660       }
1661     }
1662     return false;
1663   }
1664 };
1665 
1666 // cachewb node for guaranteeing writeback of the cache line at a
1667 // given address to (non-volatile) RAM
1668 class CacheWBNode : public Node {
1669 public:
1670   CacheWBNode(Node *ctrl, Node *mem, Node *addr) : Node(ctrl, mem, addr) {}
1671   virtual int Opcode() const;
1672   virtual uint ideal_reg() const { return NotAMachineReg; }
1673   virtual uint match_edge(uint idx) const { return (idx == 2); }
1674   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1675   virtual const Type *bottom_type() const { return Type::MEMORY; }
1676 };
1677 
1678 // cachewb pre sync node for ensuring that writebacks are serialised
1679 // relative to preceding or following stores
1680 class CacheWBPreSyncNode : public Node {
1681 public:
1682   CacheWBPreSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1683   virtual int Opcode() const;
1684   virtual uint ideal_reg() const { return NotAMachineReg; }
1685   virtual uint match_edge(uint idx) const { return false; }
1686   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1687   virtual const Type *bottom_type() const { return Type::MEMORY; }
1688 };
1689 
1690 // cachewb pre sync node for ensuring that writebacks are serialised
1691 // relative to preceding or following stores
1692 class CacheWBPostSyncNode : public Node {
1693 public:
1694   CacheWBPostSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1695   virtual int Opcode() const;
1696   virtual uint ideal_reg() const { return NotAMachineReg; }
1697   virtual uint match_edge(uint idx) const { return false; }
1698   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1699   virtual const Type *bottom_type() const { return Type::MEMORY; }
1700 };
1701 
1702 //------------------------------Prefetch---------------------------------------
1703 
1704 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1705 class PrefetchAllocationNode : public Node {
1706 public:
1707   PrefetchAllocationNode(Node *mem, Node *adr) : Node(0,mem,adr) {}
1708   virtual int Opcode() const;
1709   virtual uint ideal_reg() const { return NotAMachineReg; }
1710   virtual uint match_edge(uint idx) const { return idx==2; }
1711   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1712 };
1713 
1714 #endif // SHARE_OPTO_MEMNODE_HPP