1 /*
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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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  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) 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 Node* Ideal(PhaseGVN* phase, bool can_reshape);
 521   virtual int Opcode() const;
 522   virtual uint ideal_reg() const { return Op_RegN; }
 523   virtual int store_Opcode() const { return Op_StoreN; }
 524   virtual BasicType memory_type() const { return T_NARROWOOP; }
 525 };
 526 
 527 //------------------------------LoadKlassNode----------------------------------
 528 // Load a Klass from an object
 529 class LoadKlassNode : public LoadPNode {
 530 private:
 531   LoadKlassNode(Node* mem, Node* adr, const TypePtr* at, const TypeKlassPtr* tk, MemOrd mo)
 532     : LoadPNode(nullptr, mem, adr, at, tk, mo) {}
 533 
 534 public:
 535   virtual int Opcode() const;
 536   virtual const Type* Value(PhaseGVN* phase) const;
 537   virtual Node* Identity(PhaseGVN* phase);
 538   virtual bool depends_only_on_test() const { return true; }
 539 
 540   // Polymorphic factory method:
 541   static Node* make(PhaseGVN& gvn, Node* mem, Node* adr, const TypePtr* at,
 542                     const TypeKlassPtr* tk = TypeInstKlassPtr::OBJECT);
 543 };
 544 
 545 //------------------------------LoadNKlassNode---------------------------------
 546 // Load a narrow Klass from an object.
 547 // With compact headers, the input address (adr) does not point at the exact
 548 // header position where the (narrow) class pointer is located, but into the
 549 // middle of the mark word (see oopDesc::klass_offset_in_bytes()). This node
 550 // implicitly shifts the loaded value (markWord::klass_shift_at_offset bits) to
 551 // extract the actual class pointer. C2's type system is agnostic on whether the
 552 // input address directly points into the class pointer.
 553 class LoadNKlassNode : public LoadNNode {
 554 private:
 555   friend Node* LoadKlassNode::make(PhaseGVN&, Node*, Node*, const TypePtr*, const TypeKlassPtr*);
 556   LoadNKlassNode(Node* mem, Node* adr, const TypePtr* at, const TypeNarrowKlass* tk, MemOrd mo)
 557     : LoadNNode(nullptr, mem, adr, at, tk, mo) {}
 558 
 559 public:
 560   virtual int Opcode() const;
 561   virtual uint ideal_reg() const { return Op_RegN; }
 562   virtual int store_Opcode() const { return Op_StoreNKlass; }
 563   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 564 
 565   virtual const Type* Value(PhaseGVN* phase) const;
 566   virtual Node* Identity(PhaseGVN* phase);
 567   virtual bool depends_only_on_test() const { return true; }
 568 };
 569 
 570 //------------------------------StoreNode--------------------------------------
 571 // Store value; requires Store, Address and Value
 572 class StoreNode : public MemNode {
 573 private:
 574   // On platforms with weak memory ordering (e.g., PPC) we distinguish
 575   // stores that can be reordered, and such requiring release semantics to
 576   // adhere to the Java specification.  The required behaviour is stored in
 577   // this field.
 578   const MemOrd _mo;
 579   // Needed for proper cloning.
 580   virtual uint size_of() const { return sizeof(*this); }
 581 protected:
 582   virtual bool cmp( const Node &n ) const;
 583   virtual bool depends_only_on_test() const { return false; }
 584 
 585   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
 586   Node* Ideal_sign_extended_input(PhaseGVN* phase, int num_rejected_bits);
 587 
 588 public:
 589   // We must ensure that stores of object references will be visible
 590   // only after the object's initialization. So the callers of this
 591   // procedure must indicate that the store requires `release'
 592   // semantics, if the stored value is an object reference that might
 593   // point to a new object and may become externally visible.
 594   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 595     : MemNode(c, mem, adr, at, val), _mo(mo) {
 596     init_class_id(Class_Store);
 597   }
 598   StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
 599     : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
 600     init_class_id(Class_Store);
 601   }
 602 
 603   inline bool is_unordered() const { return !is_release(); }
 604   inline bool is_release() const {
 605     assert((_mo == unordered || _mo == release), "unexpected");
 606     return _mo == release;
 607   }
 608 
 609   // Conservatively release stores of object references in order to
 610   // ensure visibility of object initialization.
 611   static inline MemOrd release_if_reference(const BasicType t) {
 612 #ifdef AARCH64
 613     // AArch64 doesn't need a release store here because object
 614     // initialization contains the necessary barriers.
 615     return unordered;
 616 #else
 617     const MemOrd mo = (t == T_ARRAY ||
 618                        t == T_ADDRESS || // Might be the address of an object reference (`boxing').
 619                        t == T_OBJECT) ? release : unordered;
 620     return mo;
 621 #endif
 622   }
 623 
 624   // Polymorphic factory method
 625   //
 626   // We must ensure that stores of object references will be visible
 627   // only after the object's initialization. So the callers of this
 628   // procedure must indicate that the store requires `release'
 629   // semantics, if the stored value is an object reference that might
 630   // point to a new object and may become externally visible.
 631   static StoreNode* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
 632                          const TypePtr* at, Node* val, BasicType bt,
 633                          MemOrd mo, bool require_atomic_access = false);
 634 
 635   virtual uint hash() const;    // Check the type
 636 
 637   // If the store is to Field memory and the pointer is non-null, we can
 638   // zero out the control input.
 639   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 640 
 641   // Compute a new Type for this node.  Basically we just do the pre-check,
 642   // then call the virtual add() to set the type.
 643   virtual const Type* Value(PhaseGVN* phase) const;
 644 
 645   // Check for identity function on memory (Load then Store at same address)
 646   virtual Node* Identity(PhaseGVN* phase);
 647 
 648   // Do not match memory edge
 649   virtual uint match_edge(uint idx) const;
 650 
 651   virtual const Type *bottom_type() const;  // returns Type::MEMORY
 652 
 653   // Map a store opcode to its corresponding own opcode, trivially.
 654   virtual int store_Opcode() const { return Opcode(); }
 655 
 656   // have all possible loads of the value stored been optimized away?
 657   bool value_never_loaded(PhaseValues* phase) const;
 658 
 659   bool  has_reinterpret_variant(const Type* vt);
 660   Node* convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt);
 661 
 662   MemBarNode* trailing_membar() const;
 663 };
 664 
 665 //------------------------------StoreBNode-------------------------------------
 666 // Store byte to memory
 667 class StoreBNode : public StoreNode {
 668 public:
 669   StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 670     : StoreNode(c, mem, adr, at, val, mo) {}
 671   virtual int Opcode() const;
 672   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 673   virtual BasicType memory_type() const { return T_BYTE; }
 674 };
 675 
 676 //------------------------------StoreCNode-------------------------------------
 677 // Store char/short to memory
 678 class StoreCNode : public StoreNode {
 679 public:
 680   StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 681     : StoreNode(c, mem, adr, at, val, mo) {}
 682   virtual int Opcode() const;
 683   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 684   virtual BasicType memory_type() const { return T_CHAR; }
 685 };
 686 
 687 //------------------------------StoreINode-------------------------------------
 688 // Store int to memory
 689 class StoreINode : public StoreNode {
 690 public:
 691   StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 692     : StoreNode(c, mem, adr, at, val, mo) {}
 693   virtual int Opcode() const;
 694   virtual BasicType memory_type() const { return T_INT; }
 695 };
 696 
 697 //------------------------------StoreLNode-------------------------------------
 698 // Store long to memory
 699 class StoreLNode : public StoreNode {
 700   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 701   virtual bool cmp( const Node &n ) const {
 702     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
 703       && StoreNode::cmp(n);
 704   }
 705   virtual uint size_of() const { return sizeof(*this); }
 706   const bool _require_atomic_access;  // is piecewise store forbidden?
 707 
 708 public:
 709   StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
 710     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 711   virtual int Opcode() const;
 712   virtual BasicType memory_type() const { return T_LONG; }
 713   bool require_atomic_access() const { return _require_atomic_access; }
 714 
 715 #ifndef PRODUCT
 716   virtual void dump_spec(outputStream *st) const {
 717     StoreNode::dump_spec(st);
 718     if (_require_atomic_access)  st->print(" Atomic!");
 719   }
 720 #endif
 721 };
 722 
 723 // Special StoreL for flat stores that emits GC barriers for field at 'oop_off' in the backend
 724 class StoreLSpecialNode : public StoreNode {
 725 
 726 public:
 727   StoreLSpecialNode(Node* c, Node* mem, Node* adr, const TypePtr* at, Node* val, Node* oop_off, MemOrd mo)
 728     : StoreNode(c, mem, adr, at, val, mo) {
 729     set_mismatched_access();
 730     if (oop_off != nullptr) {
 731       add_req(oop_off);
 732     }
 733   }
 734   virtual int Opcode() const;
 735   virtual BasicType memory_type() const { return T_LONG; }
 736 
 737   virtual uint match_edge(uint idx) const { return idx == MemNode::Address ||
 738                                                    idx == MemNode::ValueIn ||
 739                                                    idx == MemNode::ValueIn + 1; }
 740 };
 741 
 742 //------------------------------StoreFNode-------------------------------------
 743 // Store float to memory
 744 class StoreFNode : public StoreNode {
 745 public:
 746   StoreFNode(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_FLOAT; }
 750 };
 751 
 752 //------------------------------StoreDNode-------------------------------------
 753 // Store double to memory
 754 class StoreDNode : public StoreNode {
 755   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
 756   virtual bool cmp( const Node &n ) const {
 757     return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
 758       && StoreNode::cmp(n);
 759   }
 760   virtual uint size_of() const { return sizeof(*this); }
 761   const bool _require_atomic_access;  // is piecewise store forbidden?
 762 public:
 763   StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
 764              MemOrd mo, bool require_atomic_access = false)
 765     : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
 766   virtual int Opcode() const;
 767   virtual BasicType memory_type() const { return T_DOUBLE; }
 768   bool require_atomic_access() const { return _require_atomic_access; }
 769 
 770 #ifndef PRODUCT
 771   virtual void dump_spec(outputStream *st) const {
 772     StoreNode::dump_spec(st);
 773     if (_require_atomic_access)  st->print(" Atomic!");
 774   }
 775 #endif
 776 
 777 };
 778 
 779 //------------------------------StorePNode-------------------------------------
 780 // Store pointer to memory
 781 class StorePNode : public StoreNode {
 782 public:
 783   StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 784     : StoreNode(c, mem, adr, at, val, mo) {}
 785   virtual int Opcode() const;
 786   virtual BasicType memory_type() const { return T_ADDRESS; }
 787 };
 788 
 789 //------------------------------StoreNNode-------------------------------------
 790 // Store narrow oop to memory
 791 class StoreNNode : public StoreNode {
 792 public:
 793   StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 794     : StoreNode(c, mem, adr, at, val, mo) {}
 795   virtual int Opcode() const;
 796   virtual BasicType memory_type() const { return T_NARROWOOP; }
 797 };
 798 
 799 //------------------------------StoreNKlassNode--------------------------------------
 800 // Store narrow klass to memory
 801 class StoreNKlassNode : public StoreNNode {
 802 public:
 803   StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
 804     : StoreNNode(c, mem, adr, at, val, mo) {}
 805   virtual int Opcode() const;
 806   virtual BasicType memory_type() const { return T_NARROWKLASS; }
 807 };
 808 
 809 //------------------------------SCMemProjNode---------------------------------------
 810 // This class defines a projection of the memory  state of a store conditional node.
 811 // These nodes return a value, but also update memory.
 812 class SCMemProjNode : public ProjNode {
 813 public:
 814   enum {SCMEMPROJCON = (uint)-2};
 815   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
 816   virtual int Opcode() const;
 817   virtual bool      is_CFG() const  { return false; }
 818   virtual const Type *bottom_type() const {return Type::MEMORY;}
 819   virtual const TypePtr *adr_type() const {
 820     Node* ctrl = in(0);
 821     if (ctrl == nullptr)  return nullptr; // node is dead
 822     return ctrl->in(MemNode::Memory)->adr_type();
 823   }
 824   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
 825   virtual const Type* Value(PhaseGVN* phase) const;
 826 #ifndef PRODUCT
 827   virtual void dump_spec(outputStream *st) const {};
 828 #endif
 829 };
 830 
 831 //------------------------------LoadStoreNode---------------------------
 832 // Note: is_Mem() method returns 'true' for this class.
 833 class LoadStoreNode : public Node {
 834 private:
 835   const Type* const _type;      // What kind of value is loaded?
 836   const TypePtr* _adr_type;     // What kind of memory is being addressed?
 837   uint8_t _barrier_data;        // Bit field with barrier information
 838   virtual uint size_of() const; // Size is bigger
 839 public:
 840   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
 841   virtual bool depends_only_on_test() const { return false; }
 842   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }
 843 
 844   virtual const Type *bottom_type() const { return _type; }
 845   virtual uint ideal_reg() const;
 846   virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
 847   virtual const Type* Value(PhaseGVN* phase) const;
 848 
 849   bool result_not_used() const;
 850   MemBarNode* trailing_membar() const;
 851 
 852   uint8_t barrier_data() { return _barrier_data; }
 853   void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
 854 };
 855 
 856 class LoadStoreConditionalNode : public LoadStoreNode {
 857 public:
 858   enum {
 859     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 860   };
 861   LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
 862   virtual const Type* Value(PhaseGVN* phase) const;
 863 };
 864 
 865 class CompareAndSwapNode : public LoadStoreConditionalNode {
 866 private:
 867   const MemNode::MemOrd _mem_ord;
 868 public:
 869   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) {}
 870   MemNode::MemOrd order() const {
 871     return _mem_ord;
 872   }
 873   virtual uint size_of() const { return sizeof(*this); }
 874 };
 875 
 876 class CompareAndExchangeNode : public LoadStoreNode {
 877 private:
 878   const MemNode::MemOrd _mem_ord;
 879 public:
 880   enum {
 881     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
 882   };
 883   CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
 884     LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
 885      init_req(ExpectedIn, ex );
 886   }
 887 
 888   MemNode::MemOrd order() const {
 889     return _mem_ord;
 890   }
 891   virtual uint size_of() const { return sizeof(*this); }
 892 };
 893 
 894 //------------------------------CompareAndSwapBNode---------------------------
 895 class CompareAndSwapBNode : public CompareAndSwapNode {
 896 public:
 897   CompareAndSwapBNode( 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 //------------------------------CompareAndSwapSNode---------------------------
 902 class CompareAndSwapSNode : public CompareAndSwapNode {
 903 public:
 904   CompareAndSwapSNode( 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 //------------------------------CompareAndSwapINode---------------------------
 909 class CompareAndSwapINode : public CompareAndSwapNode {
 910 public:
 911   CompareAndSwapINode( 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 //------------------------------CompareAndSwapLNode---------------------------
 916 class CompareAndSwapLNode : public CompareAndSwapNode {
 917 public:
 918   CompareAndSwapLNode( 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 //------------------------------CompareAndSwapPNode---------------------------
 923 class CompareAndSwapPNode : public CompareAndSwapNode {
 924 public:
 925   CompareAndSwapPNode( 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 //------------------------------CompareAndSwapNNode---------------------------
 930 class CompareAndSwapNNode : public CompareAndSwapNode {
 931 public:
 932   CompareAndSwapNNode( 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 //------------------------------WeakCompareAndSwapBNode---------------------------
 937 class WeakCompareAndSwapBNode : public CompareAndSwapNode {
 938 public:
 939   WeakCompareAndSwapBNode( 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 //------------------------------WeakCompareAndSwapSNode---------------------------
 944 class WeakCompareAndSwapSNode : public CompareAndSwapNode {
 945 public:
 946   WeakCompareAndSwapSNode( 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 //------------------------------WeakCompareAndSwapINode---------------------------
 951 class WeakCompareAndSwapINode : public CompareAndSwapNode {
 952 public:
 953   WeakCompareAndSwapINode( 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 //------------------------------WeakCompareAndSwapLNode---------------------------
 958 class WeakCompareAndSwapLNode : public CompareAndSwapNode {
 959 public:
 960   WeakCompareAndSwapLNode( 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 //------------------------------WeakCompareAndSwapPNode---------------------------
 965 class WeakCompareAndSwapPNode : public CompareAndSwapNode {
 966 public:
 967   WeakCompareAndSwapPNode( 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 //------------------------------WeakCompareAndSwapNNode---------------------------
 972 class WeakCompareAndSwapNNode : public CompareAndSwapNode {
 973 public:
 974   WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
 975   virtual int Opcode() const;
 976 };
 977 
 978 //------------------------------CompareAndExchangeBNode---------------------------
 979 class CompareAndExchangeBNode : public CompareAndExchangeNode {
 980 public:
 981   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) { }
 982   virtual int Opcode() const;
 983 };
 984 
 985 
 986 //------------------------------CompareAndExchangeSNode---------------------------
 987 class CompareAndExchangeSNode : public CompareAndExchangeNode {
 988 public:
 989   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) { }
 990   virtual int Opcode() const;
 991 };
 992 
 993 //------------------------------CompareAndExchangeLNode---------------------------
 994 class CompareAndExchangeLNode : public CompareAndExchangeNode {
 995 public:
 996   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) { }
 997   virtual int Opcode() const;
 998 };
 999 
1000 
1001 //------------------------------CompareAndExchangeINode---------------------------
1002 class CompareAndExchangeINode : public CompareAndExchangeNode {
1003 public:
1004   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) { }
1005   virtual int Opcode() const;
1006 };
1007 
1008 
1009 //------------------------------CompareAndExchangePNode---------------------------
1010 class CompareAndExchangePNode : public CompareAndExchangeNode {
1011 public:
1012   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) { }
1013   virtual int Opcode() const;
1014 };
1015 
1016 //------------------------------CompareAndExchangeNNode---------------------------
1017 class CompareAndExchangeNNode : public CompareAndExchangeNode {
1018 public:
1019   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) { }
1020   virtual int Opcode() const;
1021 };
1022 
1023 //------------------------------GetAndAddBNode---------------------------
1024 class GetAndAddBNode : public LoadStoreNode {
1025 public:
1026   GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1027   virtual int Opcode() const;
1028 };
1029 
1030 //------------------------------GetAndAddSNode---------------------------
1031 class GetAndAddSNode : public LoadStoreNode {
1032 public:
1033   GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1034   virtual int Opcode() const;
1035 };
1036 
1037 //------------------------------GetAndAddINode---------------------------
1038 class GetAndAddINode : public LoadStoreNode {
1039 public:
1040   GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1041   virtual int Opcode() const;
1042 };
1043 
1044 //------------------------------GetAndAddLNode---------------------------
1045 class GetAndAddLNode : public LoadStoreNode {
1046 public:
1047   GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1048   virtual int Opcode() const;
1049 };
1050 
1051 //------------------------------GetAndSetBNode---------------------------
1052 class GetAndSetBNode : public LoadStoreNode {
1053 public:
1054   GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
1055   virtual int Opcode() const;
1056 };
1057 
1058 //------------------------------GetAndSetSNode---------------------------
1059 class GetAndSetSNode : public LoadStoreNode {
1060 public:
1061   GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
1062   virtual int Opcode() const;
1063 };
1064 
1065 //------------------------------GetAndSetINode---------------------------
1066 class GetAndSetINode : public LoadStoreNode {
1067 public:
1068   GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
1069   virtual int Opcode() const;
1070 };
1071 
1072 //------------------------------GetAndSetLNode---------------------------
1073 class GetAndSetLNode : public LoadStoreNode {
1074 public:
1075   GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
1076   virtual int Opcode() const;
1077 };
1078 
1079 //------------------------------GetAndSetPNode---------------------------
1080 class GetAndSetPNode : public LoadStoreNode {
1081 public:
1082   GetAndSetPNode( 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 //------------------------------GetAndSetNNode---------------------------
1087 class GetAndSetNNode : public LoadStoreNode {
1088 public:
1089   GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
1090   virtual int Opcode() const;
1091 };
1092 
1093 //------------------------------ClearArray-------------------------------------
1094 class ClearArrayNode: public Node {
1095 private:
1096   bool _is_large;
1097   bool _word_copy_only;
1098 public:
1099   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, Node* val, bool is_large)
1100     : Node(ctrl, arymem, word_cnt, base, val), _is_large(is_large),
1101       _word_copy_only(val->bottom_type()->isa_long() && (!val->bottom_type()->is_long()->is_con() || val->bottom_type()->is_long()->get_con() != 0)) {
1102     init_class_id(Class_ClearArray);
1103   }
1104   virtual int         Opcode() const;
1105   virtual const Type *bottom_type() const { return Type::MEMORY; }
1106   // ClearArray modifies array elements, and so affects only the
1107   // array memory addressed by the bottom_type of its base address.
1108   virtual const class TypePtr *adr_type() const;
1109   virtual Node* Identity(PhaseGVN* phase);
1110   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1111   virtual uint match_edge(uint idx) const;
1112   bool is_large() const { return _is_large; }
1113   bool word_copy_only() const { return _word_copy_only; }
1114 
1115   // Clear the given area of an object or array.
1116   // The start offset must always be aligned mod BytesPerInt.
1117   // The end offset must always be aligned mod BytesPerLong.
1118   // Return the new memory.
1119   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1120                             Node* val,
1121                             Node* raw_val,
1122                             intptr_t start_offset,
1123                             intptr_t end_offset,
1124                             PhaseGVN* phase);
1125   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1126                             Node* val,
1127                             Node* raw_val,
1128                             intptr_t start_offset,
1129                             Node* end_offset,
1130                             PhaseGVN* phase);
1131   static Node* clear_memory(Node* control, Node* mem, Node* dest,
1132                             Node* raw_val,
1133                             Node* start_offset,
1134                             Node* end_offset,
1135                             PhaseGVN* phase);
1136   // Return allocation input memory edge if it is different instance
1137   // or itself if it is the one we are looking for.
1138   static bool step_through(Node** np, uint instance_id, PhaseValues* phase);
1139 };
1140 
1141 //------------------------------MemBar-----------------------------------------
1142 // There are different flavors of Memory Barriers to match the Java Memory
1143 // Model.  Monitor-enter and volatile-load act as Acquires: no following ref
1144 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
1145 // volatile-load.  Monitor-exit and volatile-store act as Release: no
1146 // preceding ref can be moved to after them.  We insert a MemBar-Release
1147 // before a FastUnlock or volatile-store.  All volatiles need to be
1148 // serialized, so we follow all volatile-stores with a MemBar-Volatile to
1149 // separate it from any following volatile-load.
1150 class MemBarNode: public MultiNode {
1151   virtual uint hash() const ;                  // { return NO_HASH; }
1152   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1153 
1154   virtual uint size_of() const { return sizeof(*this); }
1155   // Memory type this node is serializing.  Usually either rawptr or bottom.
1156   const TypePtr* _adr_type;
1157 
1158   // How is this membar related to a nearby memory access?
1159   enum {
1160     Standalone,
1161     TrailingLoad,
1162     TrailingStore,
1163     LeadingStore,
1164     TrailingLoadStore,
1165     LeadingLoadStore,
1166     TrailingPartialArrayCopy
1167   } _kind;
1168 
1169 #ifdef ASSERT
1170   uint _pair_idx;
1171 #endif
1172 
1173 public:
1174   enum {
1175     Precedent = TypeFunc::Parms  // optional edge to force precedence
1176   };
1177   MemBarNode(Compile* C, int alias_idx, Node* precedent);
1178   virtual int Opcode() const = 0;
1179   virtual const class TypePtr *adr_type() const { return _adr_type; }
1180   virtual const Type* Value(PhaseGVN* phase) const;
1181   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1182   virtual uint match_edge(uint idx) const { return 0; }
1183   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
1184   virtual Node *match(const ProjNode *proj, const Matcher *m, const RegMask* mask);
1185   // Factory method.  Builds a wide or narrow membar.
1186   // Optional 'precedent' becomes an extra edge if not null.
1187   static MemBarNode* make(Compile* C, int opcode,
1188                           int alias_idx = Compile::AliasIdxBot,
1189                           Node* precedent = nullptr);
1190 
1191   MemBarNode* trailing_membar() const;
1192   MemBarNode* leading_membar() const;
1193 
1194   void set_trailing_load() { _kind = TrailingLoad; }
1195   bool trailing_load() const { return _kind == TrailingLoad; }
1196   bool trailing_store() const { return _kind == TrailingStore; }
1197   bool leading_store() const { return _kind == LeadingStore; }
1198   bool trailing_load_store() const { return _kind == TrailingLoadStore; }
1199   bool leading_load_store() const { return _kind == LeadingLoadStore; }
1200   bool trailing() const { return _kind == TrailingLoad || _kind == TrailingStore || _kind == TrailingLoadStore; }
1201   bool leading() const { return _kind == LeadingStore || _kind == LeadingLoadStore; }
1202   bool standalone() const { return _kind == Standalone; }
1203   void set_trailing_partial_array_copy() { _kind = TrailingPartialArrayCopy; }
1204   bool trailing_partial_array_copy() const { return _kind == TrailingPartialArrayCopy; }
1205 
1206   static void set_store_pair(MemBarNode* leading, MemBarNode* trailing);
1207   static void set_load_store_pair(MemBarNode* leading, MemBarNode* trailing);
1208 
1209   void remove(PhaseIterGVN *igvn);
1210 };
1211 
1212 // "Acquire" - no following ref can move before (but earlier refs can
1213 // follow, like an early Load stalled in cache).  Requires multi-cpu
1214 // visibility.  Inserted after a volatile load.
1215 class MemBarAcquireNode: public MemBarNode {
1216 public:
1217   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
1218     : MemBarNode(C, alias_idx, precedent) {}
1219   virtual int Opcode() const;
1220 };
1221 
1222 // "Acquire" - no following ref can move before (but earlier refs can
1223 // follow, like an early Load stalled in cache).  Requires multi-cpu
1224 // visibility.  Inserted independent of any load, as required
1225 // for intrinsic Unsafe.loadFence().
1226 class LoadFenceNode: public MemBarNode {
1227 public:
1228   LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
1229     : MemBarNode(C, alias_idx, precedent) {}
1230   virtual int Opcode() const;
1231 };
1232 
1233 // "Release" - no earlier ref can move after (but later refs can move
1234 // up, like a speculative pipelined cache-hitting Load).  Requires
1235 // multi-cpu visibility.  Inserted before a volatile store.
1236 class MemBarReleaseNode: public MemBarNode {
1237 public:
1238   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
1239     : MemBarNode(C, alias_idx, precedent) {}
1240   virtual int Opcode() const;
1241 };
1242 
1243 // "Release" - no earlier ref can move after (but later refs can move
1244 // up, like a speculative pipelined cache-hitting Load).  Requires
1245 // multi-cpu visibility.  Inserted independent of any store, as required
1246 // for intrinsic Unsafe.storeFence().
1247 class StoreFenceNode: public MemBarNode {
1248 public:
1249   StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1250     : MemBarNode(C, alias_idx, precedent) {}
1251   virtual int Opcode() const;
1252 };
1253 
1254 // "Acquire" - no following ref can move before (but earlier refs can
1255 // follow, like an early Load stalled in cache).  Requires multi-cpu
1256 // visibility.  Inserted after a FastLock.
1257 class MemBarAcquireLockNode: public MemBarNode {
1258 public:
1259   MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
1260     : MemBarNode(C, alias_idx, precedent) {}
1261   virtual int Opcode() const;
1262 };
1263 
1264 // "Release" - no earlier ref can move after (but later refs can move
1265 // up, like a speculative pipelined cache-hitting Load).  Requires
1266 // multi-cpu visibility.  Inserted before a FastUnLock.
1267 class MemBarReleaseLockNode: public MemBarNode {
1268 public:
1269   MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
1270     : MemBarNode(C, alias_idx, precedent) {}
1271   virtual int Opcode() const;
1272 };
1273 
1274 class MemBarStoreStoreNode: public MemBarNode {
1275 public:
1276   MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
1277     : MemBarNode(C, alias_idx, precedent) {
1278     init_class_id(Class_MemBarStoreStore);
1279   }
1280   virtual int Opcode() const;
1281 };
1282 
1283 class StoreStoreFenceNode: public MemBarNode {
1284 public:
1285   StoreStoreFenceNode(Compile* C, int alias_idx, Node* precedent)
1286     : MemBarNode(C, alias_idx, precedent) {}
1287   virtual int Opcode() const;
1288 };
1289 
1290 // Ordering between a volatile store and a following volatile load.
1291 // Requires multi-CPU visibility?
1292 class MemBarVolatileNode: public MemBarNode {
1293 public:
1294   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
1295     : MemBarNode(C, alias_idx, precedent) {}
1296   virtual int Opcode() const;
1297 };
1298 
1299 // Ordering within the same CPU.  Used to order unsafe memory references
1300 // inside the compiler when we lack alias info.  Not needed "outside" the
1301 // compiler because the CPU does all the ordering for us.
1302 class MemBarCPUOrderNode: public MemBarNode {
1303 public:
1304   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
1305     : MemBarNode(C, alias_idx, precedent) {}
1306   virtual int Opcode() const;
1307   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1308 };
1309 
1310 class OnSpinWaitNode: public MemBarNode {
1311 public:
1312   OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
1313     : MemBarNode(C, alias_idx, precedent) {}
1314   virtual int Opcode() const;
1315 };
1316 
1317 // Isolation of object setup after an AllocateNode and before next safepoint.
1318 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
1319 class InitializeNode: public MemBarNode {
1320   friend class AllocateNode;
1321 
1322   enum {
1323     Incomplete    = 0,
1324     Complete      = 1,
1325     WithArraycopy = 2
1326   };
1327   int _is_complete;
1328 
1329   bool _does_not_escape;
1330 
1331 public:
1332   enum {
1333     Control    = TypeFunc::Control,
1334     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
1335     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
1336     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
1337   };
1338 
1339   InitializeNode(Compile* C, int adr_type, Node* rawoop);
1340   virtual int Opcode() const;
1341   virtual uint size_of() const { return sizeof(*this); }
1342   virtual uint ideal_reg() const { return 0; } // not matched in the AD file
1343   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress
1344 
1345   // Manage incoming memory edges via a MergeMem on in(Memory):
1346   Node* memory(uint alias_idx);
1347 
1348   // The raw memory edge coming directly from the Allocation.
1349   // The contents of this memory are *always* all-zero-bits.
1350   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }
1351 
1352   // Return the corresponding allocation for this initialization (or null if none).
1353   // (Note: Both InitializeNode::allocation and AllocateNode::initialization
1354   // are defined in graphKit.cpp, which sets up the bidirectional relation.)
1355   AllocateNode* allocation();
1356 
1357   // Anything other than zeroing in this init?
1358   bool is_non_zero();
1359 
1360   // An InitializeNode must completed before macro expansion is done.
1361   // Completion requires that the AllocateNode must be followed by
1362   // initialization of the new memory to zero, then to any initializers.
1363   bool is_complete() { return _is_complete != Incomplete; }
1364   bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }
1365 
1366   // Mark complete.  (Must not yet be complete.)
1367   void set_complete(PhaseGVN* phase);
1368   void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }
1369 
1370   bool does_not_escape() { return _does_not_escape; }
1371   void set_does_not_escape() { _does_not_escape = true; }
1372 
1373 #ifdef ASSERT
1374   // ensure all non-degenerate stores are ordered and non-overlapping
1375   bool stores_are_sane(PhaseValues* phase);
1376 #endif //ASSERT
1377 
1378   // See if this store can be captured; return offset where it initializes.
1379   // Return 0 if the store cannot be moved (any sort of problem).
1380   intptr_t can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape);
1381 
1382   // Capture another store; reformat it to write my internal raw memory.
1383   // Return the captured copy, else null if there is some sort of problem.
1384   Node* capture_store(StoreNode* st, intptr_t start, PhaseGVN* phase, bool can_reshape);
1385 
1386   // Find captured store which corresponds to the range [start..start+size).
1387   // Return my own memory projection (meaning the initial zero bits)
1388   // if there is no such store.  Return null if there is a problem.
1389   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseValues* phase);
1390 
1391   // Called when the associated AllocateNode is expanded into CFG.
1392   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
1393                         intptr_t header_size, Node* size_in_bytes,
1394                         PhaseIterGVN* phase);
1395 
1396  private:
1397   void remove_extra_zeroes();
1398 
1399   // Find out where a captured store should be placed (or already is placed).
1400   int captured_store_insertion_point(intptr_t start, int size_in_bytes,
1401                                      PhaseValues* phase);
1402 
1403   static intptr_t get_store_offset(Node* st, PhaseValues* phase);
1404 
1405   Node* make_raw_address(intptr_t offset, PhaseGVN* phase);
1406 
1407   bool detect_init_independence(Node* value, PhaseGVN* phase);
1408 
1409   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
1410                                PhaseGVN* phase);
1411 
1412   intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
1413 };
1414 
1415 //------------------------------MergeMem---------------------------------------
1416 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
1417 class MergeMemNode: public Node {
1418   virtual uint hash() const ;                  // { return NO_HASH; }
1419   virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
1420   friend class MergeMemStream;
1421   MergeMemNode(Node* def);  // clients use MergeMemNode::make
1422 
1423 public:
1424   // If the input is a whole memory state, clone it with all its slices intact.
1425   // Otherwise, make a new memory state with just that base memory input.
1426   // In either case, the result is a newly created MergeMem.
1427   static MergeMemNode* make(Node* base_memory);
1428 
1429   virtual int Opcode() const;
1430   virtual Node* Identity(PhaseGVN* phase);
1431   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1432   virtual uint ideal_reg() const { return NotAMachineReg; }
1433   virtual uint match_edge(uint idx) const { return 0; }
1434   virtual const RegMask &out_RegMask() const;
1435   virtual const Type *bottom_type() const { return Type::MEMORY; }
1436   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1437   // sparse accessors
1438   // Fetch the previously stored "set_memory_at", or else the base memory.
1439   // (Caller should clone it if it is a phi-nest.)
1440   Node* memory_at(uint alias_idx) const;
1441   // set the memory, regardless of its previous value
1442   void set_memory_at(uint alias_idx, Node* n);
1443   // the "base" is the memory that provides the non-finite support
1444   Node* base_memory() const       { return in(Compile::AliasIdxBot); }
1445   // warning: setting the base can implicitly set any of the other slices too
1446   void set_base_memory(Node* def);
1447   // sentinel value which denotes a copy of the base memory:
1448   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
1449   static Node* make_empty_memory(); // where the sentinel comes from
1450   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
1451   // hook for the iterator, to perform any necessary setup
1452   void iteration_setup(const MergeMemNode* other = nullptr);
1453   // push sentinels until I am at least as long as the other (semantic no-op)
1454   void grow_to_match(const MergeMemNode* other);
1455   bool verify_sparse() const PRODUCT_RETURN0;
1456 #ifndef PRODUCT
1457   virtual void dump_spec(outputStream *st) const;
1458 #endif
1459 };
1460 
1461 class MergeMemStream : public StackObj {
1462  private:
1463   MergeMemNode*       _mm;
1464   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
1465   Node*               _mm_base;  // loop-invariant base memory of _mm
1466   int                 _idx;
1467   int                 _cnt;
1468   Node*               _mem;
1469   Node*               _mem2;
1470   int                 _cnt2;
1471 
1472   void init(MergeMemNode* mm, const MergeMemNode* mm2 = nullptr) {
1473     // subsume_node will break sparseness at times, whenever a memory slice
1474     // folds down to a copy of the base ("fat") memory.  In such a case,
1475     // the raw edge will update to base, although it should be top.
1476     // This iterator will recognize either top or base_memory as an
1477     // "empty" slice.  See is_empty, is_empty2, and next below.
1478     //
1479     // The sparseness property is repaired in MergeMemNode::Ideal.
1480     // As long as access to a MergeMem goes through this iterator
1481     // or the memory_at accessor, flaws in the sparseness will
1482     // never be observed.
1483     //
1484     // Also, iteration_setup repairs sparseness.
1485     assert(mm->verify_sparse(), "please, no dups of base");
1486     assert(mm2==nullptr || mm2->verify_sparse(), "please, no dups of base");
1487 
1488     _mm  = mm;
1489     _mm_base = mm->base_memory();
1490     _mm2 = mm2;
1491     _cnt = mm->req();
1492     _idx = Compile::AliasIdxBot-1; // start at the base memory
1493     _mem = nullptr;
1494     _mem2 = nullptr;
1495   }
1496 
1497 #ifdef ASSERT
1498   Node* check_memory() const {
1499     if (at_base_memory())
1500       return _mm->base_memory();
1501     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
1502       return _mm->memory_at(_idx);
1503     else
1504       return _mm_base;
1505   }
1506   Node* check_memory2() const {
1507     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
1508   }
1509 #endif
1510 
1511   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
1512   void assert_synch() const {
1513     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
1514            "no side-effects except through the stream");
1515   }
1516 
1517  public:
1518 
1519   // expected usages:
1520   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
1521   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }
1522 
1523   // iterate over one merge
1524   MergeMemStream(MergeMemNode* mm) {
1525     mm->iteration_setup();
1526     init(mm);
1527     debug_only(_cnt2 = 999);
1528   }
1529   // iterate in parallel over two merges
1530   // only iterates through non-empty elements of mm2
1531   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
1532     assert(mm2, "second argument must be a MergeMem also");
1533     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
1534     mm->iteration_setup(mm2);
1535     init(mm, mm2);
1536     _cnt2 = mm2->req();
1537   }
1538 #ifdef ASSERT
1539   ~MergeMemStream() {
1540     assert_synch();
1541   }
1542 #endif
1543 
1544   MergeMemNode* all_memory() const {
1545     return _mm;
1546   }
1547   Node* base_memory() const {
1548     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
1549     return _mm_base;
1550   }
1551   const MergeMemNode* all_memory2() const {
1552     assert(_mm2 != nullptr, "");
1553     return _mm2;
1554   }
1555   bool at_base_memory() const {
1556     return _idx == Compile::AliasIdxBot;
1557   }
1558   int alias_idx() const {
1559     assert(_mem, "must call next 1st");
1560     return _idx;
1561   }
1562 
1563   const TypePtr* adr_type() const {
1564     return Compile::current()->get_adr_type(alias_idx());
1565   }
1566 
1567   const TypePtr* adr_type(Compile* C) const {
1568     return C->get_adr_type(alias_idx());
1569   }
1570   bool is_empty() const {
1571     assert(_mem, "must call next 1st");
1572     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
1573     return _mem->is_top();
1574   }
1575   bool is_empty2() const {
1576     assert(_mem2, "must call next 1st");
1577     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
1578     return _mem2->is_top();
1579   }
1580   Node* memory() const {
1581     assert(!is_empty(), "must not be empty");
1582     assert_synch();
1583     return _mem;
1584   }
1585   // get the current memory, regardless of empty or non-empty status
1586   Node* force_memory() const {
1587     assert(!is_empty() || !at_base_memory(), "");
1588     // Use _mm_base to defend against updates to _mem->base_memory().
1589     Node *mem = _mem->is_top() ? _mm_base : _mem;
1590     assert(mem == check_memory(), "");
1591     return mem;
1592   }
1593   Node* memory2() const {
1594     assert(_mem2 == check_memory2(), "");
1595     return _mem2;
1596   }
1597   void set_memory(Node* mem) {
1598     if (at_base_memory()) {
1599       // Note that this does not change the invariant _mm_base.
1600       _mm->set_base_memory(mem);
1601     } else {
1602       _mm->set_memory_at(_idx, mem);
1603     }
1604     _mem = mem;
1605     assert_synch();
1606   }
1607 
1608   // Recover from a side effect to the MergeMemNode.
1609   void set_memory() {
1610     _mem = _mm->in(_idx);
1611   }
1612 
1613   bool next()  { return next(false); }
1614   bool next2() { return next(true); }
1615 
1616   bool next_non_empty()  { return next_non_empty(false); }
1617   bool next_non_empty2() { return next_non_empty(true); }
1618   // next_non_empty2 can yield states where is_empty() is true
1619 
1620  private:
1621   // find the next item, which might be empty
1622   bool next(bool have_mm2) {
1623     assert((_mm2 != nullptr) == have_mm2, "use other next");
1624     assert_synch();
1625     if (++_idx < _cnt) {
1626       // Note:  This iterator allows _mm to be non-sparse.
1627       // It behaves the same whether _mem is top or base_memory.
1628       _mem = _mm->in(_idx);
1629       if (have_mm2)
1630         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
1631       return true;
1632     }
1633     return false;
1634   }
1635 
1636   // find the next non-empty item
1637   bool next_non_empty(bool have_mm2) {
1638     while (next(have_mm2)) {
1639       if (!is_empty()) {
1640         // make sure _mem2 is filled in sensibly
1641         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
1642         return true;
1643       } else if (have_mm2 && !is_empty2()) {
1644         return true;   // is_empty() == true
1645       }
1646     }
1647     return false;
1648   }
1649 };
1650 
1651 // cachewb node for guaranteeing writeback of the cache line at a
1652 // given address to (non-volatile) RAM
1653 class CacheWBNode : public Node {
1654 public:
1655   CacheWBNode(Node *ctrl, Node *mem, Node *addr) : Node(ctrl, mem, addr) {}
1656   virtual int Opcode() const;
1657   virtual uint ideal_reg() const { return NotAMachineReg; }
1658   virtual uint match_edge(uint idx) const { return (idx == 2); }
1659   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1660   virtual const Type *bottom_type() const { return Type::MEMORY; }
1661 };
1662 
1663 // cachewb pre sync node for ensuring that writebacks are serialised
1664 // relative to preceding or following stores
1665 class CacheWBPreSyncNode : public Node {
1666 public:
1667   CacheWBPreSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1668   virtual int Opcode() const;
1669   virtual uint ideal_reg() const { return NotAMachineReg; }
1670   virtual uint match_edge(uint idx) const { return false; }
1671   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1672   virtual const Type *bottom_type() const { return Type::MEMORY; }
1673 };
1674 
1675 // cachewb pre sync node for ensuring that writebacks are serialised
1676 // relative to preceding or following stores
1677 class CacheWBPostSyncNode : public Node {
1678 public:
1679   CacheWBPostSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
1680   virtual int Opcode() const;
1681   virtual uint ideal_reg() const { return NotAMachineReg; }
1682   virtual uint match_edge(uint idx) const { return false; }
1683   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
1684   virtual const Type *bottom_type() const { return Type::MEMORY; }
1685 };
1686 
1687 //------------------------------Prefetch---------------------------------------
1688 
1689 // Allocation prefetch which may fault, TLAB size have to be adjusted.
1690 class PrefetchAllocationNode : public Node {
1691 public:
1692   PrefetchAllocationNode(Node *mem, Node *adr) : Node(nullptr,mem,adr) {}
1693   virtual int Opcode() const;
1694   virtual uint ideal_reg() const { return NotAMachineReg; }
1695   virtual uint match_edge(uint idx) const { return idx==2; }
1696   virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
1697 };
1698 
1699 #endif // SHARE_OPTO_MEMNODE_HPP