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   3  * Copyright (c) 2024, Alibaba Group Holding Limited. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
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  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
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  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  25 
  26 #ifndef SHARE_OPTO_MEMNODE_HPP
  27 #define SHARE_OPTO_MEMNODE_HPP
  28 
  29 #include "opto/multnode.hpp"
  30 #include "opto/node.hpp"
  31 #include "opto/opcodes.hpp"
  32 #include "opto/type.hpp"
  33 
  34 // Portions of code courtesy of Clifford Click
  35 
  36 class MultiNode;
  37 class PhaseCCP;
  38 class PhaseTransform;
  39 
  40 //------------------------------MemNode----------------------------------------
  41 // Load or Store, possibly throwing a null pointer exception
  42 class MemNode : public Node {
  43 private:
  44   bool _unaligned_access; // Unaligned access from unsafe
  45   bool _mismatched_access; // Mismatched access from unsafe: byte read in integer array for instance
  46   bool _unsafe_access;     // Access of unsafe origin.
  47   uint8_t _barrier_data;   // Bit field with barrier information
  48 
  49 protected:
  50 #ifdef ASSERT
  51   const TypePtr* _adr_type;     // What kind of memory is being addressed?
  52 #endif
  53   virtual uint size_of() const;
  54 public:
  55   enum { Control,               // When is it safe to do this load?
  56          Memory,                // Chunk of memory is being loaded from
  57          Address,               // Actually address, derived from base
  58          ValueIn                // Value to store
  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(PhaseValues* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { return nullptr; }
  96   ArrayCopyNode* find_array_copy_clone(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   // The following two should probably be phase-specific functions:
 109   static DomResult maybe_all_controls_dominate(Node* dom, Node* sub);
 110   static bool all_controls_dominate(Node* dom, Node* sub) {
 111     DomResult dom_result = maybe_all_controls_dominate(dom, sub);
 112     return dom_result == DomResult::Dominate;
 113   }
 114 
 115   virtual const class TypePtr *adr_type() const;  // returns bottom_type of address
 116 
 117   // Shared code for Ideal methods:
 118   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit null.
 119 
 120   // Helper function for adr_type() implementations.
 121   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = nullptr);
 122 
 123   // Raw access function, to allow copying of adr_type efficiently in
 124   // product builds and retain the debug info for debug builds.
 125   const TypePtr *raw_adr_type() const {
 126     return DEBUG_ONLY(_adr_type) NOT_DEBUG(nullptr);
 127   }
 128 
 129 #ifdef ASSERT
 130   void set_adr_type(const TypePtr* adr_type) { _adr_type = adr_type; }
 131 #endif
 132 
 133   // Return the barrier data of n, if available, or 0 otherwise.
 134   static uint8_t barrier_data(const Node* n);
 135 
 136   // Map a load or store opcode to its corresponding store opcode.
 137   // (Return -1 if unknown.)
 138   virtual int store_Opcode() const { return -1; }
 139 
 140   // What is the type of the value in memory?  (T_VOID mean "unspecified".)
 141   virtual BasicType memory_type() const = 0;
 142   virtual int memory_size() const {
 143 #ifdef ASSERT
 144     return type2aelembytes(memory_type(), true);
 145 #else
 146     return type2aelembytes(memory_type());
 147 #endif
 148   }
 149 
 150   uint8_t barrier_data() { return _barrier_data; }
 151   void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
 152 
 153   // Search through memory states which precede this node (load or store).
 154   // Look for an exact match for the address, with no intervening
 155   // aliased stores.
 156   Node* find_previous_store(PhaseValues* phase);
 157 
 158   // Can this node (load or store) accurately see a stored value in
 159   // the given memory state?  (The state may or may not be in(Memory).)
 160   Node* can_see_stored_value(Node* st, PhaseValues* phase) const;
 161 
 162   void set_unaligned_access() { _unaligned_access = true; }
 163   bool is_unaligned_access() const { return _unaligned_access; }
 164   void set_mismatched_access() { _mismatched_access = true; }
 165   bool is_mismatched_access() const { return _mismatched_access; }
 166   void set_unsafe_access() { _unsafe_access = true; }
 167   bool is_unsafe_access() const { return _unsafe_access; }
 168 
 169 #ifndef PRODUCT
 170   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
 171   virtual void dump_spec(outputStream *st) const;
 172 #endif
 173 };
 174 
 175 //------------------------------LoadNode---------------------------------------
 176 // Load value; requires Memory and Address
 177 class LoadNode : public MemNode {
 178 public:
 179   // Some loads (from unsafe) should be pinned: they don't depend only
 180   // on the dominating test.  The field _control_dependency below records
 181   // whether that node depends only on the dominating test.
 182   // Pinned and UnknownControl are similar, but differ in that Pinned
 183   // loads are not allowed to float across safepoints, whereas UnknownControl
 184   // loads are allowed to do that. Therefore, Pinned is stricter.
 185   enum ControlDependency {
 186     Pinned,
 187     UnknownControl,
 188     DependsOnlyOnTest
 189   };
 190 
 191 private:
 192   // LoadNode::hash() doesn't take the _control_dependency field
 193   // into account: If the graph already has a non-pinned LoadNode and
 194   // we add a pinned LoadNode with the same inputs, it's safe for GVN
 195   // to replace the pinned LoadNode with the non-pinned LoadNode,
 196   // otherwise it wouldn't be safe to have a non pinned LoadNode with
 197   // those inputs in the first place. If the graph already has a
 198   // pinned LoadNode and we add a non pinned LoadNode with the same
 199   // inputs, it's safe (but suboptimal) for GVN to replace the
 200   // non-pinned LoadNode by the pinned LoadNode.
 201   ControlDependency _control_dependency;
 202 
 203   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 204   // loads that can be reordered, and such requiring acquire semantics to
 205   // adhere to the Java specification.  The required behaviour is stored in
 206   // this field.
 207   const MemOrd _mo;
 208 
 209   AllocateNode* is_new_object_mark_load() const;
 210 
 211 protected:
 212   virtual bool cmp(const Node &n) const;
 213   virtual uint size_of() const; // Size is bigger
 214   // Should LoadNode::Ideal() attempt to remove control edges?
 215   virtual bool can_remove_control() const;
 216   const Type* const _type;      // What kind of value is loaded?
 217 
 218   virtual Node* find_previous_arraycopy(PhaseValues* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const;
 219 public:
 220 
 221   LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo, ControlDependency control_dependency)
 222     : MemNode(c,mem,adr,at), _control_dependency(control_dependency), _mo(mo), _type(rt) {
 223     init_class_id(Class_Load);
 224   }
 225   inline bool is_unordered() const { return !is_acquire(); }
 226   inline bool is_acquire() const {
 227     assert(_mo == unordered || _mo == acquire, "unexpected");
 228     return _mo == acquire;
 229   }
 230   inline bool is_unsigned() const {
 231     int lop = Opcode();
 232     return (lop == Op_LoadUB) || (lop == Op_LoadUS);
 233   }
 234 
 235   // Polymorphic factory method:
 236   static Node* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
 237                     const TypePtr* at, const Type* rt, BasicType bt,
 238                     MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
 239                     bool require_atomic_access = false, bool unaligned = false, bool mismatched = false, bool unsafe = false,
 240                     uint8_t barrier_data = 0);
 241 
 242   virtual uint hash()   const;  // Check the type
 243 
 244   // Handle algebraic identities here.  If we have an identity, return the Node
 245   // we are equivalent to.  We look for Load of a Store.
 246   virtual Node* Identity(PhaseGVN* phase);
 247 
 248   // If the load is from Field memory and the pointer is non-null, it might be possible to
 249   // zero out the control input.
 250   // If the offset is constant and the base is an object allocation,
 251   // try to hook me up to the exact initializing store.
 252   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 253 
 254   // Return true if it's possible to split the Load through a Phi merging the bases
 255   bool can_split_through_phi_base(PhaseGVN *phase);
 256 
 257   // Split instance field load through Phi.
 258   Node* split_through_phi(PhaseGVN *phase, bool ignore_missing_instance_id = false);
 259 
 260   // Recover original value from boxed values
 261   Node *eliminate_autobox(PhaseIterGVN *igvn);
 262 
 263   // Compute a new Type for this node.  Basically we just do the pre-check,
 264   // then call the virtual add() to set the type.
 265   virtual const Type* Value(PhaseGVN* phase) const;
 266 
 267   // Common methods for LoadKlass and LoadNKlass nodes.
 268   const Type* klass_value_common(PhaseGVN* phase) const;
 269   Node* klass_identity_common(PhaseGVN* phase);
 270 
 271   virtual uint ideal_reg() const;
 272   virtual const Type *bottom_type() const;
 273   // Following method is copied from TypeNode:
 274   void set_type(const Type* t) {
 275     assert(t != nullptr, "sanity");
 276     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 277     *(const Type**)&_type = t;   // cast away const-ness
 278     // If this node is in the hash table, make sure it doesn't need a rehash.
 279     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
 280   }
 281   const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };
 282 
 283   // Do not match memory edge
 284   virtual uint match_edge(uint idx) const;
 285 
 286   // Map a load opcode to its corresponding store opcode.
 287   virtual int store_Opcode() const = 0;
 288 
 289   // Check if the load's memory input is a Phi node with the same control.
 290   bool is_instance_field_load_with_local_phi(Node* ctrl);
 291 
 292   Node* convert_to_unsigned_load(PhaseGVN& gvn);
 293   Node* convert_to_signed_load(PhaseGVN& gvn);
 294 
 295   bool  has_reinterpret_variant(const Type* rt);
 296   Node* convert_to_reinterpret_load(PhaseGVN& gvn, const Type* rt);
 297 
 298   ControlDependency control_dependency() const { return _control_dependency; }
 299   bool has_unknown_control_dependency() const  { return _control_dependency == UnknownControl; }
 300   bool has_pinned_control_dependency() const   { return _control_dependency == Pinned; }
 301 
 302   LoadNode* pin_array_access_node() const;
 303 
 304 #ifndef PRODUCT
 305   virtual void dump_spec(outputStream *st) const;
 306 #endif
 307 #ifdef ASSERT
 308   // Helper function to allow a raw load without control edge for some cases
 309   static bool is_immutable_value(Node* adr);
 310 #endif
 311 protected:
 312   const Type* load_array_final_field(const TypeKlassPtr *tkls,
 313                                      ciKlass* klass) const;
 314 
 315   Node* can_see_arraycopy_value(Node* st, PhaseGVN* phase) const;
 316 
 317   // depends_only_on_test is almost always true, and needs to be almost always
 318   // true to enable key hoisting & commoning optimizations.  However, for the
 319   // special case of RawPtr loads from TLS top & end, and other loads performed by
 320   // GC barriers, the control edge carries the dependence preventing hoisting past
 321   // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
 322   // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
 323   // which produce results (new raw memory state) inside of loops preventing all
 324   // manner of other optimizations).  Basically, it's ugly but so is the alternative.
 325   // See comment in macro.cpp, around line 125 expand_allocate_common().
 326   virtual bool depends_only_on_test() const {
 327     return adr_type() != TypeRawPtr::BOTTOM && _control_dependency == DependsOnlyOnTest;
 328   }
 329 
 330   LoadNode* clone_pinned() const;
 331 };
 332 
 333 //------------------------------LoadBNode--------------------------------------
 334 // Load a byte (8bits signed) from memory
 335 class LoadBNode : public LoadNode {
 336 public:
 337   LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 338     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 339   virtual int Opcode() const;
 340   virtual uint ideal_reg() const { return Op_RegI; }
 341   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 342   virtual const Type* Value(PhaseGVN* phase) const;
 343   virtual int store_Opcode() const { return Op_StoreB; }
 344   virtual BasicType memory_type() const { return T_BYTE; }
 345 };
 346 
 347 //------------------------------LoadUBNode-------------------------------------
 348 // Load a unsigned byte (8bits unsigned) from memory
 349 class LoadUBNode : public LoadNode {
 350 public:
 351   LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 352     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 353   virtual int Opcode() const;
 354   virtual uint ideal_reg() const { return Op_RegI; }
 355   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
 356   virtual const Type* Value(PhaseGVN* phase) const;
 357   virtual int store_Opcode() const { return Op_StoreB; }
 358   virtual BasicType memory_type() const { return T_BYTE; }
 359 };
 360 
 361 //------------------------------LoadUSNode-------------------------------------
 362 // Load an unsigned short/char (16bits unsigned) from memory
 363 class LoadUSNode : public LoadNode {
 364 public:
 365   LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 366     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 367   virtual int Opcode() const;
 368   virtual uint ideal_reg() const { return Op_RegI; }
 369   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 370   virtual const Type* Value(PhaseGVN* phase) const;
 371   virtual int store_Opcode() const { return Op_StoreC; }
 372   virtual BasicType memory_type() const { return T_CHAR; }
 373 };
 374 
 375 //------------------------------LoadSNode--------------------------------------
 376 // Load a short (16bits signed) from memory
 377 class LoadSNode : public LoadNode {
 378 public:
 379   LoadSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 380     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 381   virtual int Opcode() const;
 382   virtual uint ideal_reg() const { return Op_RegI; }
 383   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 384   virtual const Type* Value(PhaseGVN* phase) const;
 385   virtual int store_Opcode() const { return Op_StoreC; }
 386   virtual BasicType memory_type() const { return T_SHORT; }
 387 };
 388 
 389 //------------------------------LoadINode--------------------------------------
 390 // Load an integer from memory
 391 class LoadINode : public LoadNode {
 392 public:
 393   LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 394     : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
 395   virtual int Opcode() const;
 396   virtual uint ideal_reg() const { return Op_RegI; }
 397   virtual int store_Opcode() const { return Op_StoreI; }
 398   virtual BasicType memory_type() const { return T_INT; }
 399 };
 400 
 401 //------------------------------LoadRangeNode----------------------------------
 402 // Load an array length from the array
 403 class LoadRangeNode : public LoadINode {
 404 public:
 405   LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
 406     : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
 407   virtual int Opcode() const;
 408   virtual const Type* Value(PhaseGVN* phase) const;
 409   virtual Node* Identity(PhaseGVN* phase);
 410   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 411 };
 412 
 413 //------------------------------LoadLNode--------------------------------------
 414 // Load a long from memory
 415 class LoadLNode : public LoadNode {
 416   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 417   virtual bool cmp( const Node &n ) const {
 418     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
 419       && LoadNode::cmp(n);
 420   }
 421   virtual uint size_of() const { return sizeof(*this); }
 422   const bool _require_atomic_access;  // is piecewise load forbidden?
 423 
 424 public:
 425   LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
 426             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 427     : LoadNode(c, mem, adr, at, tl, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 428   virtual int Opcode() const;
 429   virtual uint ideal_reg() const { return Op_RegL; }
 430   virtual int store_Opcode() const { return Op_StoreL; }
 431   virtual BasicType memory_type() const { return T_LONG; }
 432   bool require_atomic_access() const { return _require_atomic_access; }
 433 
 434 #ifndef PRODUCT
 435   virtual void dump_spec(outputStream *st) const {
 436     LoadNode::dump_spec(st);
 437     if (_require_atomic_access)  st->print(" Atomic!");
 438   }
 439 #endif
 440 };
 441 
 442 //------------------------------LoadL_unalignedNode----------------------------
 443 // Load a long from unaligned memory
 444 class LoadL_unalignedNode : public LoadLNode {
 445 public:
 446   LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 447     : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo, control_dependency) {}
 448   virtual int Opcode() const;
 449 };
 450 
 451 //------------------------------LoadFNode--------------------------------------
 452 // Load a float (64 bits) from memory
 453 class LoadFNode : public LoadNode {
 454 public:
 455   LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 456     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 457   virtual int Opcode() const;
 458   virtual uint ideal_reg() const { return Op_RegF; }
 459   virtual int store_Opcode() const { return Op_StoreF; }
 460   virtual BasicType memory_type() const { return T_FLOAT; }
 461 };
 462 
 463 //------------------------------LoadDNode--------------------------------------
 464 // Load a double (64 bits) from memory
 465 class LoadDNode : public LoadNode {
 466   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
 467   virtual bool cmp( const Node &n ) const {
 468     return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
 469       && LoadNode::cmp(n);
 470   }
 471   virtual uint size_of() const { return sizeof(*this); }
 472   const bool _require_atomic_access;  // is piecewise load forbidden?
 473 
 474 public:
 475   LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
 476             MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
 477     : LoadNode(c, mem, adr, at, t, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
 478   virtual int Opcode() const;
 479   virtual uint ideal_reg() const { return Op_RegD; }
 480   virtual int store_Opcode() const { return Op_StoreD; }
 481   virtual BasicType memory_type() const { return T_DOUBLE; }
 482   bool require_atomic_access() const { return _require_atomic_access; }
 483 
 484 #ifndef PRODUCT
 485   virtual void dump_spec(outputStream *st) const {
 486     LoadNode::dump_spec(st);
 487     if (_require_atomic_access)  st->print(" Atomic!");
 488   }
 489 #endif
 490 };
 491 
 492 //------------------------------LoadD_unalignedNode----------------------------
 493 // Load a double from unaligned memory
 494 class LoadD_unalignedNode : public LoadDNode {
 495 public:
 496   LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 497     : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo, control_dependency) {}
 498   virtual int Opcode() const;
 499 };
 500 
 501 //------------------------------LoadPNode--------------------------------------
 502 // Load a pointer from memory (either object or array)
 503 class LoadPNode : public LoadNode {
 504 public:
 505   LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 506     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 507   virtual int Opcode() const;
 508   virtual uint ideal_reg() const { return Op_RegP; }
 509   virtual int store_Opcode() const { return Op_StoreP; }
 510   virtual BasicType memory_type() const { return T_ADDRESS; }
 511 };
 512 
 513 
 514 //------------------------------LoadNNode--------------------------------------
 515 // Load a narrow oop from memory (either object or array)
 516 class LoadNNode : public LoadNode {
 517 public:
 518   LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
 519     : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
 520   virtual int Opcode() const;
 521   virtual uint ideal_reg() const { return Op_RegN; }
 522   virtual int store_Opcode() const { return Op_StoreN; }
 523   virtual BasicType memory_type() const { return T_NARROWOOP; }
 524 };
 525 
 526 //------------------------------LoadKlassNode----------------------------------
 527 // Load a Klass from an object
 528 class LoadKlassNode : public LoadPNode {
 529 protected:
 530   // In most cases, LoadKlassNode does not have the control input set. If the control
 531   // input is set, it must not be removed (by LoadNode::Ideal()).
 532   virtual bool can_remove_control() const;
 533 public:
 534   LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
 535     : LoadPNode(c, mem, adr, at, tk, mo) {}
 536   virtual int Opcode() const;
 537   virtual const Type* Value(PhaseGVN* phase) const;
 538   virtual Node* Identity(PhaseGVN* phase);
 539   virtual bool depends_only_on_test() const { return true; }
 540 
 541   // Polymorphic factory method:
 542   static Node* make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at,
 543                     const TypeKlassPtr* tk = TypeInstKlassPtr::OBJECT);
 544 };
 545 
 546 //------------------------------LoadNKlassNode---------------------------------
 547 // Load a narrow Klass from an object.
 548 class LoadNKlassNode : public LoadNNode {
 549 public:
 550   LoadNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeNarrowKlass *tk, MemOrd mo)
 551     : LoadNNode(c, mem, adr, at, tk, mo) {}
 552   virtual int Opcode() const;
 553   virtual uint ideal_reg() const { return Op_RegN; }
 554   virtual int store_Opcode() const { return Op_StoreNKlass; }
 555   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 556 
 557   virtual const Type* Value(PhaseGVN* phase) const;
 558   virtual Node* Identity(PhaseGVN* phase);
 559   virtual bool depends_only_on_test() const { return true; }
 560 };
 561 
 562 //------------------------------StoreNode--------------------------------------
 563 // Store value; requires Store, Address and Value
 564 class StoreNode : public MemNode {
 565 private:
 566   // On platforms with weak memory ordering (e.g., PPC, Ia64) we distinguish
 567   // stores that can be reordered, and such requiring release semantics to
 568   // adhere to the Java specification.  The required behaviour is stored in
 569   // this field.
 570   const MemOrd _mo;
 571   // Needed for proper cloning.
 572   virtual uint size_of() const { return sizeof(*this); }
 573 protected:
 574   virtual bool cmp( const Node &n ) const;
 575   virtual bool depends_only_on_test() const { return false; }
 576 
 577   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 578   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);
 579 
 580 public:
 581   // We must ensure that stores of object references will be visible
 582   // only after the object's initialization. So the callers of this
 583   // procedure must indicate that the store requires `release'
 584   // semantics, if the stored value is an object reference that might
 585   // point to a new object and may become externally visible.
 586   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 587     : MemNode(c, mem, adr, at, val), _mo(mo) {
 588     init_class_id(Class_Store);
 589   }
 590   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 591     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 592     init_class_id(Class_Store);
 593   }
 594 
 595   inline bool is_unordered() const { return !is_release(); }
 596   inline bool is_release() const {
 597     assert((_mo == unordered || _mo == release), "unexpected");
 598     return _mo == release;
 599   }
 600 
 601   // Conservatively release stores of object references in order to
 602   // ensure visibility of object initialization.
 603   static inline MemOrd release_if_reference(const BasicType t) {
 604 #ifdef AARCH64
 605     // AArch64 doesn't need a release store here because object
 606     // initialization contains the necessary barriers.
 607     return unordered;
 608 #else
 609     const MemOrd mo = (t == T_ARRAY ||
 610                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 611                        t == T_OBJECT) ? release : unordered;
 612     return mo;
 613 #endif
 614   }
 615 
 616   // Polymorphic factory method
 617   //
 618   // We must ensure that stores of object references will be visible
 619   // only after the object's initialization. So the callers of this
 620   // procedure must indicate that the store requires `release'
 621   // semantics, if the stored value is an object reference that might
 622   // point to a new object and may become externally visible.
 623   static StoreNode* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
 624                          const TypePtr* at, Node* val, BasicType bt,
 625                          MemOrd mo, bool require_atomic_access = false);
 626 
 627   virtual uint hash() const;    // Check the type
 628 
 629   // If the store is to Field memory and the pointer is non-null, we can
 630   // zero out the control input.
 631   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 632 
 633   // Compute a new Type for this node.  Basically we just do the pre-check,
 634   // then call the virtual add() to set the type.
 635   virtual const Type* Value(PhaseGVN* phase) const;
 636 
 637   // Check for identity function on memory (Load then Store at same address)
 638   virtual Node* Identity(PhaseGVN* phase);
 639 
 640   // Do not match memory edge
 641   virtual uint match_edge(uint idx) const;
 642 
 643   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 644 
 645   // Map a store opcode to its corresponding own opcode, trivially.
 646   virtual int store_Opcode() const { return Opcode(); }
 647 
 648   // have all possible loads of the value stored been optimized away?
 649   bool value_never_loaded(PhaseValues* phase) const;
 650 
 651   bool  has_reinterpret_variant(const Type* vt);
 652   Node* convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt);
 653 
 654   MemBarNode* trailing_membar() const;
 655 };
 656 
 657 //------------------------------StoreBNode-------------------------------------
 658 // Store byte to memory
 659 class StoreBNode : public StoreNode {
 660 public:
 661   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 662     : StoreNode(c, mem, adr, at, val, mo) {}
 663   virtual int Opcode() const;
 664   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 665   virtual BasicType memory_type() const { return T_BYTE; }
 666 };
 667 
 668 //------------------------------StoreCNode-------------------------------------
 669 // Store char/short to memory
 670 class StoreCNode : public StoreNode {
 671 public:
 672   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 673     : StoreNode(c, mem, adr, at, val, mo) {}
 674   virtual int Opcode() const;
 675   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 676   virtual BasicType memory_type() const { return T_CHAR; }
 677 };
 678 
 679 //------------------------------StoreINode-------------------------------------
 680 // Store int to memory
 681 class StoreINode : public StoreNode {
 682 public:
 683   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 684     : StoreNode(c, mem, adr, at, val, mo) {}
 685   virtual int Opcode() const;
 686   virtual BasicType memory_type() const { return T_INT; }
 687 };
 688 
 689 //------------------------------StoreLNode-------------------------------------
 690 // Store long to memory
 691 class StoreLNode : public StoreNode {
 692   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 693   virtual bool cmp( const Node &n ) const {
 694     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 695       && StoreNode::cmp(n);
 696   }
 697   virtual uint size_of() const { return sizeof(*this); }
 698   const bool _require_atomic_access;  // is piecewise store forbidden?
 699 
 700 public:
 701   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 702     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 703   virtual int Opcode() const;
 704   virtual BasicType memory_type() const { return T_LONG; }
 705   bool require_atomic_access() const { return _require_atomic_access; }
 706 
 707 #ifndef PRODUCT
 708   virtual void dump_spec(outputStream *st) const {
 709     StoreNode::dump_spec(st);
 710     if (_require_atomic_access)  st->print(" Atomic!");
 711   }
 712 #endif
 713 };
 714 
 715 //------------------------------StoreFNode-------------------------------------
 716 // Store float to memory
 717 class StoreFNode : public StoreNode {
 718 public:
 719   StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 720     : StoreNode(c, mem, adr, at, val, mo) {}
 721   virtual int Opcode() const;
 722   virtual BasicType memory_type() const { return T_FLOAT; }
 723 };
 724 
 725 //------------------------------StoreDNode-------------------------------------
 726 // Store double to memory
 727 class StoreDNode : public StoreNode {
 728   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 729   virtual bool cmp( const Node &n ) const {
 730     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 731       && StoreNode::cmp(n);
 732   }
 733   virtual uint size_of() const { return sizeof(*this); }
 734   const bool _require_atomic_access;  // is piecewise store forbidden?
 735 public:
 736   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 737              MemOrd mo, bool require_atomic_access = false)
 738     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 739   virtual int Opcode() const;
 740   virtual BasicType memory_type() const { return T_DOUBLE; }
 741   bool require_atomic_access() const { return _require_atomic_access; }
 742 
 743 #ifndef PRODUCT
 744   virtual void dump_spec(outputStream *st) const {
 745     StoreNode::dump_spec(st);
 746     if (_require_atomic_access)  st->print(" Atomic!");
 747   }
 748 #endif
 749 
 750 };
 751 
 752 //------------------------------StorePNode-------------------------------------
 753 // Store pointer to memory
 754 class StorePNode : public StoreNode {
 755 public:
 756   StorePNode(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_ADDRESS; }
 760 };
 761 
 762 //------------------------------StoreNNode-------------------------------------
 763 // Store narrow oop to memory
 764 class StoreNNode : public StoreNode {
 765 public:
 766   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 767     : StoreNode(c, mem, adr, at, val, mo) {}
 768   virtual int Opcode() const;
 769   virtual BasicType memory_type() const { return T_NARROWOOP; }
 770 };
 771 
 772 //------------------------------StoreNKlassNode--------------------------------------
 773 // Store narrow klass to memory
 774 class StoreNKlassNode : public StoreNNode {
 775 public:
 776   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 777     : StoreNNode(c, mem, adr, at, val, mo) {}
 778   virtual int Opcode() const;
 779   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 780 };
 781 
 782 //------------------------------SCMemProjNode---------------------------------------
 783 // This class defines a projection of the memory  state of a store conditional node.
 784 // These nodes return a value, but also update memory.
 785 class SCMemProjNode : public ProjNode {
 786 public:
 787   enum {SCMEMPROJCON = (uint)-2};
 788   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 789   virtual int Opcode() const;
 790   virtual bool      is_CFG() const  { return false; }
 791   virtual const Type *bottom_type() const {return Type::MEMORY;}
 792   virtual const TypePtr *adr_type() const {
 793     Node* ctrl = in(0);
 794     if (ctrl == nullptr)  return nullptr; // node is dead
 795     return ctrl->in(MemNode::Memory)->adr_type();
 796   }
 797   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 798   virtual const Type* Value(PhaseGVN* phase) const;
 799 #ifndef PRODUCT
 800   virtual void dump_spec(outputStream *st) const {};
 801 #endif
 802 };
 803 
 804 //------------------------------LoadStoreNode---------------------------
 805 // Note: is_Mem() method returns 'true' for this class.
 806 class LoadStoreNode : public Node {
 807 private:
 808   const Type* const _type;      // What kind of value is loaded?
 809   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 810   uint8_t _barrier_data;        // Bit field with barrier information
 811   virtual uint size_of() const; // Size is bigger
 812 public:
 813   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 814   virtual bool depends_only_on_test() const { return false; }
 815   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 816 
 817   virtual const Type *bottom_type() const { return _type; }
 818   virtual uint ideal_reg() const;
 819   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 820   virtual const Type* Value(PhaseGVN* phase) const;
 821 
 822   bool result_not_used() const;
 823   MemBarNode* trailing_membar() const;
 824 
 825   uint8_t barrier_data() { return _barrier_data; }
 826   void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
 827 };
 828 
 829 class LoadStoreConditionalNode : public LoadStoreNode {
 830 public:
 831   enum {
 832     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 833   };
 834   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 835   virtual const Type* Value(PhaseGVN* phase) const;
 836 };
 837 
 838 class CompareAndSwapNode : public LoadStoreConditionalNode {
 839 private:
 840   const MemNode::MemOrd _mem_ord;
 841 public:
 842   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) {}
 843   MemNode::MemOrd order() const {
 844     return _mem_ord;
 845   }
 846   virtual uint size_of() const { return sizeof(*this); }
 847 };
 848 
 849 class CompareAndExchangeNode : public LoadStoreNode {
 850 private:
 851   const MemNode::MemOrd _mem_ord;
 852 public:
 853   enum {
 854     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 855   };
 856   CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
 857     LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
 858      init_req(ExpectedIn, ex );
 859   }
 860 
 861   MemNode::MemOrd order() const {
 862     return _mem_ord;
 863   }
 864   virtual uint size_of() const { return sizeof(*this); }
 865 };
 866 
 867 //------------------------------CompareAndSwapBNode---------------------------
 868 class CompareAndSwapBNode : public CompareAndSwapNode {
 869 public:
 870   CompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 871   virtual int Opcode() const;
 872 };
 873 
 874 //------------------------------CompareAndSwapSNode---------------------------
 875 class CompareAndSwapSNode : public CompareAndSwapNode {
 876 public:
 877   CompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 878   virtual int Opcode() const;
 879 };
 880 
 881 //------------------------------CompareAndSwapINode---------------------------
 882 class CompareAndSwapINode : public CompareAndSwapNode {
 883 public:
 884   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 885   virtual int Opcode() const;
 886 };
 887 
 888 //------------------------------CompareAndSwapLNode---------------------------
 889 class CompareAndSwapLNode : public CompareAndSwapNode {
 890 public:
 891   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 892   virtual int Opcode() const;
 893 };
 894 
 895 //------------------------------CompareAndSwapPNode---------------------------
 896 class CompareAndSwapPNode : public CompareAndSwapNode {
 897 public:
 898   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 899   virtual int Opcode() const;
 900 };
 901 
 902 //------------------------------CompareAndSwapNNode---------------------------
 903 class CompareAndSwapNNode : public CompareAndSwapNode {
 904 public:
 905   CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 906   virtual int Opcode() const;
 907 };
 908 
 909 //------------------------------WeakCompareAndSwapBNode---------------------------
 910 class WeakCompareAndSwapBNode : public CompareAndSwapNode {
 911 public:
 912   WeakCompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 913   virtual int Opcode() const;
 914 };
 915 
 916 //------------------------------WeakCompareAndSwapSNode---------------------------
 917 class WeakCompareAndSwapSNode : public CompareAndSwapNode {
 918 public:
 919   WeakCompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 920   virtual int Opcode() const;
 921 };
 922 
 923 //------------------------------WeakCompareAndSwapINode---------------------------
 924 class WeakCompareAndSwapINode : public CompareAndSwapNode {
 925 public:
 926   WeakCompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 927   virtual int Opcode() const;
 928 };
 929 
 930 //------------------------------WeakCompareAndSwapLNode---------------------------
 931 class WeakCompareAndSwapLNode : public CompareAndSwapNode {
 932 public:
 933   WeakCompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 934   virtual int Opcode() const;
 935 };
 936 
 937 //------------------------------WeakCompareAndSwapPNode---------------------------
 938 class WeakCompareAndSwapPNode : public CompareAndSwapNode {
 939 public:
 940   WeakCompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 941   virtual int Opcode() const;
 942 };
 943 
 944 //------------------------------WeakCompareAndSwapNNode---------------------------
 945 class WeakCompareAndSwapNNode : public CompareAndSwapNode {
 946 public:
 947   WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 948   virtual int Opcode() const;
 949 };
 950 
 951 //------------------------------CompareAndExchangeBNode---------------------------
 952 class CompareAndExchangeBNode : public CompareAndExchangeNode {
 953 public:
 954   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) { }
 955   virtual int Opcode() const;
 956 };
 957 
 958 
 959 //------------------------------CompareAndExchangeSNode---------------------------
 960 class CompareAndExchangeSNode : public CompareAndExchangeNode {
 961 public:
 962   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) { }
 963   virtual int Opcode() const;
 964 };
 965 
 966 //------------------------------CompareAndExchangeLNode---------------------------
 967 class CompareAndExchangeLNode : public CompareAndExchangeNode {
 968 public:
 969   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) { }
 970   virtual int Opcode() const;
 971 };
 972 
 973 
 974 //------------------------------CompareAndExchangeINode---------------------------
 975 class CompareAndExchangeINode : public CompareAndExchangeNode {
 976 public:
 977   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) { }
 978   virtual int Opcode() const;
 979 };
 980 
 981 
 982 //------------------------------CompareAndExchangePNode---------------------------
 983 class CompareAndExchangePNode : public CompareAndExchangeNode {
 984 public:
 985   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) { }
 986   virtual int Opcode() const;
 987 };
 988 
 989 //------------------------------CompareAndExchangeNNode---------------------------
 990 class CompareAndExchangeNNode : public CompareAndExchangeNode {
 991 public:
 992   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) { }
 993   virtual int Opcode() const;
 994 };
 995 
 996 //------------------------------GetAndAddBNode---------------------------
 997 class GetAndAddBNode : public LoadStoreNode {
 998 public:
 999   GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1000   virtual int Opcode() const;
1001 };
1002 
1003 //------------------------------GetAndAddSNode---------------------------
1004 class GetAndAddSNode : public LoadStoreNode {
1005 public:
1006   GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1007   virtual int Opcode() const;
1008 };
1009 
1010 //------------------------------GetAndAddINode---------------------------
1011 class GetAndAddINode : public LoadStoreNode {
1012 public:
1013   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1014   virtual int Opcode() const;
1015 };
1016 
1017 //------------------------------GetAndAddLNode---------------------------
1018 class GetAndAddLNode : public LoadStoreNode {
1019 public:
1020   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1021   virtual int Opcode() const;
1022 };
1023 
1024 //------------------------------GetAndSetBNode---------------------------
1025 class GetAndSetBNode : public LoadStoreNode {
1026 public:
1027   GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1028   virtual int Opcode() const;
1029 };
1030 
1031 //------------------------------GetAndSetSNode---------------------------
1032 class GetAndSetSNode : public LoadStoreNode {
1033 public:
1034   GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1035   virtual int Opcode() const;
1036 };
1037 
1038 //------------------------------GetAndSetINode---------------------------
1039 class GetAndSetINode : public LoadStoreNode {
1040 public:
1041   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1042   virtual int Opcode() const;
1043 };
1044 
1045 //------------------------------GetAndSetLNode---------------------------
1046 class GetAndSetLNode : public LoadStoreNode {
1047 public:
1048   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1049   virtual int Opcode() const;
1050 };
1051 
1052 //------------------------------GetAndSetPNode---------------------------
1053 class GetAndSetPNode : public LoadStoreNode {
1054 public:
1055   GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1056   virtual int Opcode() const;
1057 };
1058 
1059 //------------------------------GetAndSetNNode---------------------------
1060 class GetAndSetNNode : public LoadStoreNode {
1061 public:
1062   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1063   virtual int Opcode() const;
1064 };
1065 
1066 //------------------------------ClearArray-------------------------------------
1067 class ClearArrayNode: public Node {
1068 private:
1069   bool _is_large;
1070   bool _word_copy_only;
1071 public:
1072   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, Node* val, bool is_large)
1073     : Node(ctrl, arymem, word_cnt, base, val), _is_large(is_large),
1074       _word_copy_only(val->bottom_type()->isa_long() && (!val->bottom_type()->is_long()->is_con() || val->bottom_type()->is_long()->get_con() != 0)) {
1075     init_class_id(Class_ClearArray);
1076   }
1077   virtual int         Opcode() const;
1078   virtual const Type *bottom_type() const { return Type::MEMORY; }
1079   // ClearArray modifies array elements, and so affects only the
1080   // array memory addressed by the bottom_type of its base address.
1081   virtual const class TypePtr *adr_type() const;
1082   virtual Node* Identity(PhaseGVN* phase);
1083   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1084   virtual uint match_edge(uint idx) const;
1085   bool is_large() const { return _is_large; }
1086   bool word_copy_only() const { return _word_copy_only; }
1087 
1088   // Clear the given area of an object or array.
1089   // The start offset must always be aligned mod BytesPerInt.
1090   // The end offset must always be aligned mod BytesPerLong.
1091   // Return the new memory.
1092   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1093                             Node* val,
1094                             Node* raw_val,
1095                             intptr_t start_offset,
1096                             intptr_t end_offset,
1097                             PhaseGVN* phase);
1098   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1099                             Node* val,
1100                             Node* raw_val,
1101                             intptr_t start_offset,
1102                             Node* end_offset,
1103                             PhaseGVN* phase);
1104   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1105                             Node* raw_val,
1106                             Node* start_offset,
1107                             Node* end_offset,
1108                             PhaseGVN* phase);
1109   // Return allocation input memory edge if it is different instance
1110   // or itself if it is the one we are looking for.
1111   static bool step_through(Node** np, uint instance_id, PhaseValues* phase);
1112 };
1113 
1114 //------------------------------MemBar-----------------------------------------
1115 // There are different flavors of Memory Barriers to match the Java Memory
1116 // Model.  Monitor-enter and volatile-load act as Acquires: no following ref
1117 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
1118 // volatile-load.  Monitor-exit and volatile-store act as Release: no
1119 // preceding ref can be moved to after them.  We insert a MemBar-Release
1120 // before a FastUnlock or volatile-store.  All volatiles need to be
1121 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
1122 // separate it from any following volatile-load.
1123 class MemBarNode: public MultiNode {
1124   virtual uint hash() const ;                  // { return NO_HASH; }
1125   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1126 
1127   virtual uint size_of() const { return sizeof(*this); }
1128   // Memory type this node is serializing.  Usually either rawptr or bottom.
1129   const TypePtr* _adr_type;
1130 
1131   // How is this membar related to a nearby memory access?
1132   enum {
1133     Standalone,
1134     TrailingLoad,
1135     TrailingStore,
1136     LeadingStore,
1137     TrailingLoadStore,
1138     LeadingLoadStore,
1139     TrailingPartialArrayCopy
1140   } _kind;
1141 
1142 #ifdef ASSERT
1143   uint _pair_idx;
1144 #endif
1145 
1146 public:
1147   enum {
1148     Precedent = TypeFunc::Parms  // optional edge to force precedence
1149   };
1150   MemBarNode(Compile* C, int alias_idx, Node* precedent);
1151   virtual int Opcode() const = 0;
1152   virtual const class TypePtr *adr_type() const { return _adr_type; }
1153   virtual const Type* Value(PhaseGVN* phase) const;
1154   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1155   virtual uint match_edge(uint idx) const { return 0; }
1156   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
1157   virtual Node *match(const ProjNode *proj, const Matcher *m, const RegMask* mask);
1158   // Factory method.  Builds a wide or narrow membar.
1159   // Optional 'precedent' becomes an extra edge if not null.
1160   static MemBarNode* make(Compile* C, int opcode,
1161                           int alias_idx = Compile::AliasIdxBot,
1162                           Node* precedent = nullptr);
1163 
1164   MemBarNode* trailing_membar() const;
1165   MemBarNode* leading_membar() const;
1166 
1167   void set_trailing_load() { _kind = TrailingLoad; }
1168   bool trailing_load() const { return _kind == TrailingLoad; }
1169   bool trailing_store() const { return _kind == TrailingStore; }
1170   bool leading_store() const { return _kind == LeadingStore; }
1171   bool trailing_load_store() const { return _kind == TrailingLoadStore; }
1172   bool leading_load_store() const { return _kind == LeadingLoadStore; }
1173   bool trailing() const { return _kind == TrailingLoad || _kind == TrailingStore || _kind == TrailingLoadStore; }
1174   bool leading() const { return _kind == LeadingStore || _kind == LeadingLoadStore; }
1175   bool standalone() const { return _kind == Standalone; }
1176   void set_trailing_partial_array_copy() { _kind = TrailingPartialArrayCopy; }
1177   bool trailing_partial_array_copy() const { return _kind == TrailingPartialArrayCopy; }
1178 
1179   static void set_store_pair(MemBarNode* leading, MemBarNode* trailing);
1180   static void set_load_store_pair(MemBarNode* leading, MemBarNode* trailing);
1181 
1182   void remove(PhaseIterGVN *igvn);
1183 };
1184 
1185 // "Acquire" - no following ref can move before (but earlier refs can
1186 // follow, like an early Load stalled in cache).  Requires multi-cpu
1187 // visibility.  Inserted after a volatile load.
1188 class MemBarAcquireNode: public MemBarNode {
1189 public:
1190   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1191     : MemBarNode(C, alias_idx, precedent) {}
1192   virtual int Opcode() const;
1193 };
1194 
1195 // "Acquire" - no following ref can move before (but earlier refs can
1196 // follow, like an early Load stalled in cache).  Requires multi-cpu
1197 // visibility.  Inserted independent of any load, as required
1198 // for intrinsic Unsafe.loadFence().
1199 class LoadFenceNode: public MemBarNode {
1200 public:
1201   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
1202     : MemBarNode(C, alias_idx, precedent) {}
1203   virtual int Opcode() const;
1204 };
1205 
1206 // "Release" - no earlier ref can move after (but later refs can move
1207 // up, like a speculative pipelined cache-hitting Load).  Requires
1208 // multi-cpu visibility.  Inserted before a volatile store.
1209 class MemBarReleaseNode: public MemBarNode {
1210 public:
1211   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1212     : MemBarNode(C, alias_idx, precedent) {}
1213   virtual int Opcode() const;
1214 };
1215 
1216 // "Release" - no earlier ref can move after (but later refs can move
1217 // up, like a speculative pipelined cache-hitting Load).  Requires
1218 // multi-cpu visibility.  Inserted independent of any store, as required
1219 // for intrinsic Unsafe.storeFence().
1220 class StoreFenceNode: public MemBarNode {
1221 public:
1222   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1223     : MemBarNode(C, alias_idx, precedent) {}
1224   virtual int Opcode() const;
1225 };
1226 
1227 // "Acquire" - no following ref can move before (but earlier refs can
1228 // follow, like an early Load stalled in cache).  Requires multi-cpu
1229 // visibility.  Inserted after a FastLock.
1230 class MemBarAcquireLockNode: public MemBarNode {
1231 public:
1232   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1233     : MemBarNode(C, alias_idx, precedent) {}
1234   virtual int Opcode() const;
1235 };
1236 
1237 // "Release" - no earlier ref can move after (but later refs can move
1238 // up, like a speculative pipelined cache-hitting Load).  Requires
1239 // multi-cpu visibility.  Inserted before a FastUnLock.
1240 class MemBarReleaseLockNode: public MemBarNode {
1241 public:
1242   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1243     : MemBarNode(C, alias_idx, precedent) {}
1244   virtual int Opcode() const;
1245 };
1246 
1247 class MemBarStoreStoreNode: public MemBarNode {
1248 public:
1249   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1250     : MemBarNode(C, alias_idx, precedent) {
1251     init_class_id(Class_MemBarStoreStore);
1252   }
1253   virtual int Opcode() const;
1254 };
1255 
1256 class StoreStoreFenceNode: public MemBarNode {
1257 public:
1258   StoreStoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1259     : MemBarNode(C, alias_idx, precedent) {}
1260   virtual int Opcode() const;
1261 };
1262 
1263 // Ordering between a volatile store and a following volatile load.
1264 // Requires multi-CPU visibility?
1265 class MemBarVolatileNode: public MemBarNode {
1266 public:
1267   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1268     : MemBarNode(C, alias_idx, precedent) {}
1269   virtual int Opcode() const;
1270 };
1271 
1272 // Ordering within the same CPU.  Used to order unsafe memory references
1273 // inside the compiler when we lack alias info.  Not needed "outside" the
1274 // compiler because the CPU does all the ordering for us.
1275 class MemBarCPUOrderNode: public MemBarNode {
1276 public:
1277   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1278     : MemBarNode(C, alias_idx, precedent) {}
1279   virtual int Opcode() const;
1280   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1281 };
1282 
1283 class OnSpinWaitNode: public MemBarNode {
1284 public:
1285   OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
1286     : MemBarNode(C, alias_idx, precedent) {}
1287   virtual int Opcode() const;
1288 };
1289 
1290 // Isolation of object setup after an AllocateNode and before next safepoint.
1291 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1292 class InitializeNode: public MemBarNode {
1293   friend class AllocateNode;
1294 
1295   enum {
1296     Incomplete    = 0,
1297     Complete      = 1,
1298     WithArraycopy = 2
1299   };
1300   int _is_complete;
1301 
1302   bool _does_not_escape;
1303 
1304 public:
1305   enum {
1306     Control    = TypeFunc::Control,
1307     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1308     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1309     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1310   };
1311 
1312   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1313   virtual int Opcode() const;
1314   virtual uint size_of() const { return sizeof(*this); }
1315   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1316   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1317 
1318   // Manage incoming memory edges via a MergeMem on in(Memory):
1319   Node* memory(uint alias_idx);
1320 
1321   // The raw memory edge coming directly from the Allocation.
1322   // The contents of this memory are *always* all-zero-bits.
1323   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1324 
1325   // Return the corresponding allocation for this initialization (or null if none).
1326   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1327   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1328   AllocateNode* allocation();
1329 
1330   // Anything other than zeroing in this init?
1331   bool is_non_zero();
1332 
1333   // An InitializeNode must completed before macro expansion is done.
1334   // Completion requires that the AllocateNode must be followed by
1335   // initialization of the new memory to zero, then to any initializers.
1336   bool is_complete() { return _is_complete != Incomplete; }
1337   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1338 
1339   // Mark complete.  (Must not yet be complete.)
1340   void set_complete(PhaseGVN* phase);
1341   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1342 
1343   bool does_not_escape() { return _does_not_escape; }
1344   void set_does_not_escape() { _does_not_escape = true; }
1345 
1346 #ifdef ASSERT
1347   // ensure all non-degenerate stores are ordered and non-overlapping
1348   bool stores_are_sane(PhaseValues* phase);
1349 #endif //ASSERT
1350 
1351   // See if this store can be captured; return offset where it initializes.
1352   // Return 0 if the store cannot be moved (any sort of problem).
1353   intptr_t can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape);
1354 
1355   // Capture another store; reformat it to write my internal raw memory.
1356   // Return the captured copy, else null if there is some sort of problem.
1357   Node* capture_store(StoreNode* st, intptr_t start, PhaseGVN* phase, bool can_reshape);
1358 
1359   // Find captured store which corresponds to the range [start..start+size).
1360   // Return my own memory projection (meaning the initial zero bits)
1361   // if there is no such store.  Return null if there is a problem.
1362   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseValues* phase);
1363 
1364   // Called when the associated AllocateNode is expanded into CFG.
1365   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1366                         intptr_t header_size, Node* size_in_bytes,
1367                         PhaseIterGVN* phase);
1368 
1369  private:
1370   void remove_extra_zeroes();
1371 
1372   // Find out where a captured store should be placed (or already is placed).
1373   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1374                                      PhaseValues* phase);
1375 
1376   static intptr_t get_store_offset(Node* st, PhaseValues* phase);
1377 
1378   Node* make_raw_address(intptr_t offset, PhaseGVN* phase);
1379 
1380   bool detect_init_independence(Node* value, PhaseGVN* phase);
1381 
1382   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1383                                PhaseGVN* phase);
1384 
1385   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1386 };
1387 
1388 //------------------------------MergeMem---------------------------------------
1389 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1390 class MergeMemNode: public Node {
1391   virtual uint hash() const ;                  // { return NO_HASH; }
1392   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1393   friend class MergeMemStream;
1394   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1395 
1396 public:
1397   // If the input is a whole memory state, clone it with all its slices intact.
1398   // Otherwise, make a new memory state with just that base memory input.
1399   // In either case, the result is a newly created MergeMem.
1400   static MergeMemNode* make(Node* base_memory);
1401 
1402   virtual int Opcode() const;
1403   virtual Node* Identity(PhaseGVN* phase);
1404   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1405   virtual uint ideal_reg() const { return NotAMachineReg; }
1406   virtual uint match_edge(uint idx) const { return 0; }
1407   virtual const RegMask &out_RegMask() const;
1408   virtual const Type *bottom_type() const { return Type::MEMORY; }
1409   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1410   // sparse accessors
1411   // Fetch the previously stored "set_memory_at", or else the base memory.
1412   // (Caller should clone it if it is a phi-nest.)
1413   Node* memory_at(uint alias_idx) const;
1414   // set the memory, regardless of its previous value
1415   void set_memory_at(uint alias_idx, Node* n);
1416   // the "base" is the memory that provides the non-finite support
1417   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1418   // warning: setting the base can implicitly set any of the other slices too
1419   void set_base_memory(Node* def);
1420   // sentinel value which denotes a copy of the base memory:
1421   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1422   static Node* make_empty_memory(); // where the sentinel comes from
1423   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1424   // hook for the iterator, to perform any necessary setup
1425   void iteration_setup(const MergeMemNode* other = nullptr);
1426   // push sentinels until I am at least as long as the other (semantic no-op)
1427   void grow_to_match(const MergeMemNode* other);
1428   bool verify_sparse() const PRODUCT_RETURN0;
1429 #ifndef PRODUCT
1430   virtual void dump_spec(outputStream *st) const;
1431 #endif
1432 };
1433 
1434 class MergeMemStream : public StackObj {
1435  private:
1436   MergeMemNode*       _mm;
1437   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1438   Node*               _mm_base;  // loop-invariant base memory of _mm
1439   int                 _idx;
1440   int                 _cnt;
1441   Node*               _mem;
1442   Node*               _mem2;
1443   int                 _cnt2;
1444 
1445   void init(MergeMemNode* mm, const MergeMemNode* mm2 = nullptr) {
1446     // subsume_node will break sparseness at times, whenever a memory slice
1447     // folds down to a copy of the base ("fat") memory.  In such a case,
1448     // the raw edge will update to base, although it should be top.
1449     // This iterator will recognize either top or base_memory as an
1450     // "empty" slice.  See is_empty, is_empty2, and next below.
1451     //
1452     // The sparseness property is repaired in MergeMemNode::Ideal.
1453     // As long as access to a MergeMem goes through this iterator
1454     // or the memory_at accessor, flaws in the sparseness will
1455     // never be observed.
1456     //
1457     // Also, iteration_setup repairs sparseness.
1458     assert(mm->verify_sparse(), "please, no dups of base");
1459     assert(mm2==nullptr || mm2->verify_sparse(), "please, no dups of base");
1460 
1461     _mm  = mm;
1462     _mm_base = mm->base_memory();
1463     _mm2 = mm2;
1464     _cnt = mm->req();
1465     _idx = Compile::AliasIdxBot-1; // start at the base memory
1466     _mem = nullptr;
1467     _mem2 = nullptr;
1468   }
1469 
1470 #ifdef ASSERT
1471   Node* check_memory() const {
1472     if (at_base_memory())
1473       return _mm->base_memory();
1474     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1475       return _mm->memory_at(_idx);
1476     else
1477       return _mm_base;
1478   }
1479   Node* check_memory2() const {
1480     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1481   }
1482 #endif
1483 
1484   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1485   void assert_synch() const {
1486     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1487            "no side-effects except through the stream");
1488   }
1489 
1490  public:
1491 
1492   // expected usages:
1493   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1494   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1495 
1496   // iterate over one merge
1497   MergeMemStream(MergeMemNode* mm) {
1498     mm->iteration_setup();
1499     init(mm);
1500     debug_only(_cnt2 = 999);
1501   }
1502   // iterate in parallel over two merges
1503   // only iterates through non-empty elements of mm2
1504   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1505     assert(mm2, "second argument must be a MergeMem also");
1506     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1507     mm->iteration_setup(mm2);
1508     init(mm, mm2);
1509     _cnt2 = mm2->req();
1510   }
1511 #ifdef ASSERT
1512   ~MergeMemStream() {
1513     assert_synch();
1514   }
1515 #endif
1516 
1517   MergeMemNode* all_memory() const {
1518     return _mm;
1519   }
1520   Node* base_memory() const {
1521     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1522     return _mm_base;
1523   }
1524   const MergeMemNode* all_memory2() const {
1525     assert(_mm2 != nullptr, "");
1526     return _mm2;
1527   }
1528   bool at_base_memory() const {
1529     return _idx == Compile::AliasIdxBot;
1530   }
1531   int alias_idx() const {
1532     assert(_mem, "must call next 1st");
1533     return _idx;
1534   }
1535 
1536   const TypePtr* adr_type() const {
1537     return Compile::current()->get_adr_type(alias_idx());
1538   }
1539 
1540   const TypePtr* adr_type(Compile* C) const {
1541     return C->get_adr_type(alias_idx());
1542   }
1543   bool is_empty() const {
1544     assert(_mem, "must call next 1st");
1545     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1546     return _mem->is_top();
1547   }
1548   bool is_empty2() const {
1549     assert(_mem2, "must call next 1st");
1550     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1551     return _mem2->is_top();
1552   }
1553   Node* memory() const {
1554     assert(!is_empty(), "must not be empty");
1555     assert_synch();
1556     return _mem;
1557   }
1558   // get the current memory, regardless of empty or non-empty status
1559   Node* force_memory() const {
1560     assert(!is_empty() || !at_base_memory(), "");
1561     // Use _mm_base to defend against updates to _mem->base_memory().
1562     Node *mem = _mem->is_top() ? _mm_base : _mem;
1563     assert(mem == check_memory(), "");
1564     return mem;
1565   }
1566   Node* memory2() const {
1567     assert(_mem2 == check_memory2(), "");
1568     return _mem2;
1569   }
1570   void set_memory(Node* mem) {
1571     if (at_base_memory()) {
1572       // Note that this does not change the invariant _mm_base.
1573       _mm->set_base_memory(mem);
1574     } else {
1575       _mm->set_memory_at(_idx, mem);
1576     }
1577     _mem = mem;
1578     assert_synch();
1579   }
1580 
1581   // Recover from a side effect to the MergeMemNode.
1582   void set_memory() {
1583     _mem = _mm->in(_idx);
1584   }
1585 
1586   bool next()  { return next(false); }
1587   bool next2() { return next(true); }
1588 
1589   bool next_non_empty()  { return next_non_empty(false); }
1590   bool next_non_empty2() { return next_non_empty(true); }
1591   // next_non_empty2 can yield states where is_empty() is true
1592 
1593  private:
1594   // find the next item, which might be empty
1595   bool next(bool have_mm2) {
1596     assert((_mm2 != nullptr) == have_mm2, "use other next");
1597     assert_synch();
1598     if (++_idx < _cnt) {
1599       // Note:  This iterator allows _mm to be non-sparse.
1600       // It behaves the same whether _mem is top or base_memory.
1601       _mem = _mm->in(_idx);
1602       if (have_mm2)
1603         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1604       return true;
1605     }
1606     return false;
1607   }
1608 
1609   // find the next non-empty item
1610   bool next_non_empty(bool have_mm2) {
1611     while (next(have_mm2)) {
1612       if (!is_empty()) {
1613         // make sure _mem2 is filled in sensibly
1614         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1615         return true;
1616       } else if (have_mm2 && !is_empty2()) {
1617         return true;   // is_empty() == true
1618       }
1619     }
1620     return false;
1621   }
1622 };
1623 
1624 // cachewb node for guaranteeing writeback of the cache line at a
1625 // given address to (non-volatile) RAM
1626 class CacheWBNode : public Node {
1627 public:
1628   CacheWBNode(Node *ctrl, Node *mem, Node *addr) : Node(ctrl, mem, addr) {}
1629   virtual int Opcode() const;
1630   virtual uint ideal_reg() const { return NotAMachineReg; }
1631   virtual uint match_edge(uint idx) const { return (idx == 2); }
1632   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1633   virtual const Type *bottom_type() const { return Type::MEMORY; }
1634 };
1635 
1636 // cachewb pre sync node for ensuring that writebacks are serialised
1637 // relative to preceding or following stores
1638 class CacheWBPreSyncNode : public Node {
1639 public:
1640   CacheWBPreSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1641   virtual int Opcode() const;
1642   virtual uint ideal_reg() const { return NotAMachineReg; }
1643   virtual uint match_edge(uint idx) const { return false; }
1644   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1645   virtual const Type *bottom_type() const { return Type::MEMORY; }
1646 };
1647 
1648 // cachewb pre sync node for ensuring that writebacks are serialised
1649 // relative to preceding or following stores
1650 class CacheWBPostSyncNode : public Node {
1651 public:
1652   CacheWBPostSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1653   virtual int Opcode() const;
1654   virtual uint ideal_reg() const { return NotAMachineReg; }
1655   virtual uint match_edge(uint idx) const { return false; }
1656   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1657   virtual const Type *bottom_type() const { return Type::MEMORY; }
1658 };
1659 
1660 //------------------------------Prefetch---------------------------------------
1661 
1662 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1663 class PrefetchAllocationNode : public Node {
1664 public:
1665   PrefetchAllocationNode(Node *mem, Node *adr) : Node(nullptr,mem,adr) {}
1666   virtual int Opcode() const;
1667   virtual uint ideal_reg() const { return NotAMachineReg; }
1668   virtual uint match_edge(uint idx) const { return idx==2; }
1669   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1670 };
1671 
1672 #endif // SHARE_OPTO_MEMNODE_HPP