Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 // Predefined classes

 class ciField;

 class ValueStack;

 class InstructionPrinter;

 class IRScope;

 class LIR_OprDesc;

 typedef LIR_OprDesc* LIR_Opr;

 // Instruction class hierarchy

 //

 // All leaf classes in the class hierarchy are concrete classes

 // (i.e., are instantiated). All other classes are abstract and

 // serve factoring.

 class Instruction;

 class   Phi;

 class   Local;

 class   Constant;

 class   AccessField;

 class     LoadField;

 class     StoreField;

 class   AccessArray;

 class     ArrayLength;

 class     AccessIndexed;

 class       LoadIndexed;

 class       StoreIndexed;

 class   NegateOp;

 class   Op2;

 class     ArithmeticOp;

 class     ShiftOp;

 class     LogicOp;

 class     CompareOp;

 class     IfOp;

 class   Convert;

 class   NullCheck;

 class   OsrEntry;

 class   ExceptionObject;

 class   StateSplit;

 class     Invoke;

 class     NewInstance;

 class     NewArray;

 class       NewTypeArray;

 class       NewObjectArray;

 class       NewMultiArray;

 class     TypeCheck;

 class       CheckCast;

 class       InstanceOf;

 class     AccessMonitor;

 class       MonitorEnter;

 class       MonitorExit;

 class     Intrinsic;

 class     BlockBegin;

 class     BlockEnd;

 class       Goto;

 class       If;

 class       IfInstanceOf;

 class       Switch;

 class         TableSwitch;

 class         LookupSwitch;

 class       Return;

 class       Throw;

 class       Base;

 class   RoundFP;

 class   UnsafeOp;

 class     UnsafeRawOp;

 class       UnsafeGetRaw;

 class       UnsafePutRaw;

 class     UnsafeObjectOp;

 class       UnsafeGetObject;

 class       UnsafePutObject;

 class       UnsafePrefetch;

 class         UnsafePrefetchRead;

 class         UnsafePrefetchWrite;

 class   ProfileCall;

 class   ProfileInvoke;

 // A Value is a reference to the instruction creating the value

 typedef Instruction* Value;

 define_array(ValueArray, Value)

 define_stack(Values, ValueArray)

 define_array(ValueStackArray, ValueStack*)

 define_stack(ValueStackStack, ValueStackArray)

 // BlockClosure is the base class for block traversal/iteration.

 class BlockClosure: public CompilationResourceObj {

  public:

   virtual void block_do(BlockBegin* block)       = 0;

 };

 // A simple closure class for visiting the values of an Instruction

 class ValueVisitor: public StackObj {

  public:

   virtual void visit(Value* v) = 0;

 };

 // Some array and list classes

 define_array(BlockBeginArray, BlockBegin*)

 define_stack(_BlockList, BlockBeginArray)

 class BlockList: public _BlockList {

  public:

   BlockList(): _BlockList() {}

   BlockList(const int size): _BlockList(size) {}

   BlockList(const int size, BlockBegin* init): _BlockList(size, init) {}

   void iterate_forward(BlockClosure* closure);

   void iterate_backward(BlockClosure* closure);

   void blocks_do(void f(BlockBegin*));

   void values_do(ValueVisitor* f);

   void print(bool cfg_only = false, bool live_only = false) PRODUCT_RETURN;

 };

 // InstructionVisitors provide type-based dispatch for instructions.

 // For each concrete Instruction class X, a virtual function do_X is

 // provided. Functionality that needs to be implemented for all classes

 // (e.g., printing, code generation) is factored out into a specialised

 // visitor instead of added to the Instruction classes itself.

 class InstructionVisitor: public StackObj {

  public:

   virtual void do_Phi            (Phi*             x) = 0;

   virtual void do_Local          (Local*           x) = 0;

   virtual void do_Constant       (Constant*        x) = 0;

   virtual void do_LoadField      (LoadField*       x) = 0;

   virtual void do_StoreField     (StoreField*      x) = 0;

   virtual void do_ArrayLength    (ArrayLength*     x) = 0;

   virtual void do_LoadIndexed    (LoadIndexed*     x) = 0;

   virtual void do_StoreIndexed   (StoreIndexed*    x) = 0;

   virtual void do_NegateOp       (NegateOp*        x) = 0;

   virtual void do_ArithmeticOp   (ArithmeticOp*    x) = 0;

   virtual void do_ShiftOp        (ShiftOp*         x) = 0;

   virtual void do_LogicOp        (LogicOp*         x) = 0;

   virtual void do_CompareOp      (CompareOp*       x) = 0;

   virtual void do_IfOp           (IfOp*            x) = 0;

   virtual void do_Convert        (Convert*         x) = 0;

   virtual void do_NullCheck      (NullCheck*       x) = 0;

   virtual void do_Invoke         (Invoke*          x) = 0;

   virtual void do_NewInstance    (NewInstance*     x) = 0;

   virtual void do_NewTypeArray   (NewTypeArray*    x) = 0;

   virtual void do_NewObjectArray (NewObjectArray*  x) = 0;

   virtual void do_NewMultiArray  (NewMultiArray*   x) = 0;

   virtual void do_CheckCast      (CheckCast*       x) = 0;

   virtual void do_InstanceOf     (InstanceOf*      x) = 0;

   virtual void do_MonitorEnter   (MonitorEnter*    x) = 0;

   virtual void do_MonitorExit    (MonitorExit*     x) = 0;

   virtual void do_Intrinsic      (Intrinsic*       x) = 0;

   virtual void do_BlockBegin     (BlockBegin*      x) = 0;

   virtual void do_Goto           (Goto*            x) = 0;

   virtual void do_If             (If*              x) = 0;

   virtual void do_IfInstanceOf   (IfInstanceOf*    x) = 0;

   virtual void do_TableSwitch    (TableSwitch*     x) = 0;

   virtual void do_LookupSwitch   (LookupSwitch*    x) = 0;

   virtual void do_Return         (Return*          x) = 0;

   virtual void do_Throw          (Throw*           x) = 0;

   virtual void do_Base           (Base*            x) = 0;

   virtual void do_OsrEntry       (OsrEntry*        x) = 0;

   virtual void do_ExceptionObject(ExceptionObject* x) = 0;

   virtual void do_RoundFP        (RoundFP*         x) = 0;

   virtual void do_UnsafeGetRaw   (UnsafeGetRaw*    x) = 0;

   virtual void do_UnsafePutRaw   (UnsafePutRaw*    x) = 0;

   virtual void do_UnsafeGetObject(UnsafeGetObject* x) = 0;

   virtual void do_UnsafePutObject(UnsafePutObject* x) = 0;

   virtual void do_UnsafePrefetchRead (UnsafePrefetchRead*  x) = 0;

   virtual void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) = 0;

   virtual void do_ProfileCall    (ProfileCall*     x) = 0;

   virtual void do_ProfileInvoke  (ProfileInvoke*   x) = 0;

 };

 // Hashing support

 //

 // Note: This hash functions affect the performance

 //       of ValueMap - make changes carefully!

 #define HASH1(x1            )                    ((intx)(x1))

 #define HASH2(x1, x2        )                    ((HASH1(x1        ) << 7) ^ HASH1(x2))

 #define HASH3(x1, x2, x3    )                    ((HASH2(x1, x2    ) << 7) ^ HASH1(x3))

 #define HASH4(x1, x2, x3, x4)                    ((HASH3(x1, x2, x3) << 7) ^ HASH1(x4))

 // The following macros are used to implement instruction-specific hashing.

 // By default, each instruction implements hash() and is_equal(Value), used

 // for value numbering/common subexpression elimination. The default imple-

 // mentation disables value numbering. Each instruction which can be value-

 // numbered, should define corresponding hash() and is_equal(Value) functions

 // via the macros below. The f arguments specify all the values/op codes, etc.

 // that need to be identical for two instructions to be identical.

 //

 // Note: The default implementation of hash() returns 0 in order to indicate

 //       that the instruction should not be considered for value numbering.

 //       The currently used hash functions do not guarantee that never a 0

 //       is produced. While this is still correct, it may be a performance

 //       bug (no value numbering for that node). However, this situation is

 //       so unlikely, that we are not going to handle it specially.

 #define HASHING1(class_name, enabled, f1)             \

   virtual intx hash() const {                         \

     return (enabled) ? HASH2(name(), f1) : 0;         \

   }                                                   \

   virtual bool is_equal(Value v) const {              \

     if (!(enabled)  ) return false;                   \

     class_name* _v = v->as_##class_name();            \

     if (_v == NULL  ) return false;                   \

     if (f1 != _v->f1) return false;                   \

     return true;                                      \

   }                                                   \

 #define HASHING2(class_name, enabled, f1, f2)         \

   virtual intx hash() const {                         \

     return (enabled) ? HASH3(name(), f1, f2) : 0;     \

   }                                                   \

   virtual bool is_equal(Value v) const {              \

     if (!(enabled)  ) return false;                   \

     class_name* _v = v->as_##class_name();            \

     if (_v == NULL  ) return false;                   \

     if (f1 != _v->f1) return false;                   \

     if (f2 != _v->f2) return false;                   \

     return true;                                      \

   }                                                   \

 #define HASHING3(class_name, enabled, f1, f2, f3)     \

   virtual intx hash() const {                          \

     return (enabled) ? HASH4(name(), f1, f2, f3) : 0; \

   }                                                   \

   virtual bool is_equal(Value v) const {              \

     if (!(enabled)  ) return false;                   \

     class_name* _v = v->as_##class_name();            \

     if (_v == NULL  ) return false;                   \

     if (f1 != _v->f1) return false;                   \

     if (f2 != _v->f2) return false;                   \

     if (f3 != _v->f3) return false;                   \

     return true;                                      \

   }                                                   \

 // The mother of all instructions...

 class Instruction: public CompilationResourceObj {

  private:

   int          _id;                              // the unique instruction id

 #ifndef PRODUCT

   int          _printable_bci;                   // the bci of the instruction for printing

 #endif

   int          _use_count;                       // the number of instructions refering to this value (w/o prev/next); only roots can have use count = 0 or > 1

   int          _pin_state;                       // set of PinReason describing the reason for pinning

   ValueType*   _type;                            // the instruction value type

   Instruction* _next;                            // the next instruction if any (NULL for BlockEnd instructions)

   Instruction* _subst;                           // the substitution instruction if any

   LIR_Opr      _operand;                         // LIR specific information

   unsigned int _flags;                           // Flag bits

   ValueStack*  _state_before;                    // Copy of state with input operands still on stack (or NULL)

   ValueStack*  _exception_state;                 // Copy of state for exception handling

   XHandlers*   _exception_handlers;              // Flat list of exception handlers covering this instruction

   friend class UseCountComputer;

   friend class BlockBegin;

   void update_exception_state(ValueStack* state);

   bool has_printable_bci() const                 { return NOT_PRODUCT(_printable_bci != -99) PRODUCT_ONLY(false); }

  protected:

   void set_type(ValueType* type) {

     assert(type != NULL, "type must exist");

     _type = type;

   }

  public:

   void* operator new(size_t size) {

     Compilation* c = Compilation::current();

     void* res = c->arena()->Amalloc(size);

     ((Instruction*)res)->_id = c->get_next_id();

     return res;

   }

   enum InstructionFlag {

     NeedsNullCheckFlag = 0,

     CanTrapFlag,

     DirectCompareFlag,

     IsEliminatedFlag,

     IsInitializedFlag,

     IsLoadedFlag,

     IsSafepointFlag,

     IsStaticFlag,

     IsStrictfpFlag,

     NeedsStoreCheckFlag,

     NeedsWriteBarrierFlag,

     PreservesStateFlag,

     TargetIsFinalFlag,

     TargetIsLoadedFlag,

     TargetIsStrictfpFlag,

     UnorderedIsTrueFlag,

     NeedsPatchingFlag,

     ThrowIncompatibleClassChangeErrorFlag,

     ProfileMDOFlag,

     IsLinkedInBlockFlag,

     InstructionLastFlag

   };

  public:

   bool check_flag(InstructionFlag id) const      { return (_flags & (1 << id)) != 0;    }

   void set_flag(InstructionFlag id, bool f)      { _flags = f ? (_flags | (1 << id)) : (_flags & ~(1 << id)); };

   // 'globally' used condition values

   enum Condition {

     eql, neq, lss, leq, gtr, geq

   };

   // Instructions may be pinned for many reasons and under certain conditions

   // with enough knowledge it's possible to safely unpin them.

   enum PinReason {

       PinUnknown           = 1 << 0

     , PinExplicitNullCheck = 1 << 3

     , PinStackForStateSplit= 1 << 12

     , PinStateSplitConstructor= 1 << 13

     , PinGlobalValueNumbering= 1 << 14

   };

   static Condition mirror(Condition cond);

   static Condition negate(Condition cond);

   // initialization

   static int number_of_instructions() {

     return Compilation::current()->number_of_instructions();

   }

   // creation

   Instruction(ValueType* type, ValueStack* state_before = NULL, bool type_is_constant = false)

   : _use_count(0)

 #ifndef PRODUCT

   , _printable_bci(-99)

 #endif

   , _pin_state(0)

   , _type(type)

   , _next(NULL)

   , _subst(NULL)

   , _flags(0)

   , _operand(LIR_OprFact::illegalOpr)

   , _state_before(state_before)

   , _exception_handlers(NULL)

   {

     check_state(state_before);

     assert(type != NULL && (!type->is_constant() || type_is_constant), "type must exist");

     update_exception_state(_state_before);

   }

   // accessors

   int id() const                                 { return _id; }

 #ifndef PRODUCT

   int printable_bci() const                      { assert(has_printable_bci(), "_printable_bci should have been set"); return _printable_bci; }

   void set_printable_bci(int bci)                { NOT_PRODUCT(_printable_bci = bci;) }

 #endif

   int use_count() const                          { return _use_count; }

   int pin_state() const                          { return _pin_state; }

   bool is_pinned() const                         { return _pin_state != 0 || PinAllInstructions; }

   ValueType* type() const                        { return _type; }

   Instruction* prev(BlockBegin* block);          // use carefully, expensive operation

   Instruction* next() const                      { return _next; }

   bool has_subst() const                         { return _subst != NULL; }

   Instruction* subst()                           { return _subst == NULL ? this : _subst->subst(); }

   LIR_Opr operand() const                        { return _operand; }

   void set_needs_null_check(bool f)              { set_flag(NeedsNullCheckFlag, f); }

   bool needs_null_check() const                  { return check_flag(NeedsNullCheckFlag); }

   bool is_linked() const                         { return check_flag(IsLinkedInBlockFlag); }

   bool can_be_linked()                           { return as_Local() == NULL && as_Phi() == NULL; }

   bool has_uses() const                          { return use_count() > 0; }

   ValueStack* state_before() const               { return _state_before; }

   ValueStack* exception_state() const            { return _exception_state; }

   virtual bool needs_exception_state() const     { return true; }

   XHandlers* exception_handlers() const          { return _exception_handlers; }

   // manipulation

   void pin(PinReason reason)                     { _pin_state |= reason; }

   void pin()                                     { _pin_state |= PinUnknown; }

   // DANGEROUS: only used by EliminateStores

   void unpin(PinReason reason)                   { assert((reason & PinUnknown) == 0, "can't unpin unknown state"); _pin_state &= ~reason; }

   Instruction* set_next(Instruction* next) {

     assert(next->has_printable_bci(), "_printable_bci should have been set");

     assert(next != NULL, "must not be NULL");

     assert(as_BlockEnd() == NULL, "BlockEnd instructions must have no next");

     assert(next->can_be_linked(), "shouldn't link these instructions into list");

     next->set_flag(Instruction::IsLinkedInBlockFlag, true);

     _next = next;

     return next;

   }

   Instruction* set_next(Instruction* next, int bci) {

 #ifndef PRODUCT

     next->set_printable_bci(bci);

 #endif

     return set_next(next);

   }

   void set_subst(Instruction* subst)             {

     assert(subst == NULL ||

            type()->base() == subst->type()->base() ||

            subst->type()->base() == illegalType, "type can't change");

     _subst = subst;

   }

   void set_exception_handlers(XHandlers *xhandlers) { _exception_handlers = xhandlers; }

   void set_exception_state(ValueStack* s)        { check_state(s); _exception_state = s; }

   // machine-specifics

   void set_operand(LIR_Opr operand)              { assert(operand != LIR_OprFact::illegalOpr, "operand must exist"); _operand = operand; }

   void clear_operand()                           { _operand = LIR_OprFact::illegalOpr; }

   // generic

   virtual Instruction*      as_Instruction()     { return this; } // to satisfy HASHING1 macro

   virtual Phi*           as_Phi()          { return NULL; }

   virtual Local*            as_Local()           { return NULL; }

   virtual Constant*         as_Constant()        { return NULL; }

   virtual AccessField*      as_AccessField()     { return NULL; }

   virtual LoadField*        as_LoadField()       { return NULL; }

   virtual StoreField*       as_StoreField()      { return NULL; }

   virtual AccessArray*      as_AccessArray()     { return NULL; }

   virtual ArrayLength*      as_ArrayLength()     { return NULL; }

   virtual AccessIndexed*    as_AccessIndexed()   { return NULL; }

   virtual LoadIndexed*      as_LoadIndexed()     { return NULL; }

   virtual StoreIndexed*     as_StoreIndexed()    { return NULL; }

   virtual NegateOp*         as_NegateOp()        { return NULL; }

   virtual Op2*              as_Op2()             { return NULL; }

   virtual ArithmeticOp*     as_ArithmeticOp()    { return NULL; }

   virtual ShiftOp*          as_ShiftOp()         { return NULL; }

   virtual LogicOp*          as_LogicOp()         { return NULL; }

   virtual CompareOp*        as_CompareOp()       { return NULL; }

   virtual IfOp*             as_IfOp()            { return NULL; }

   virtual Convert*          as_Convert()         { return NULL; }

   virtual NullCheck*        as_NullCheck()       { return NULL; }

   virtual OsrEntry*         as_OsrEntry()        { return NULL; }

   virtual StateSplit*       as_StateSplit()      { return NULL; }

   virtual Invoke*           as_Invoke()          { return NULL; }

   virtual NewInstance*      as_NewInstance()     { return NULL; }

   virtual NewArray*         as_NewArray()        { return NULL; }

   virtual NewTypeArray*     as_NewTypeArray()    { return NULL; }

   virtual NewObjectArray*   as_NewObjectArray()  { return NULL; }

   virtual NewMultiArray*    as_NewMultiArray()   { return NULL; }

   virtual TypeCheck*        as_TypeCheck()       { return NULL; }

   virtual CheckCast*        as_CheckCast()       { return NULL; }

   virtual InstanceOf*       as_InstanceOf()      { return NULL; }

   virtual AccessMonitor*    as_AccessMonitor()   { return NULL; }

   virtual MonitorEnter*     as_MonitorEnter()    { return NULL; }

   virtual MonitorExit*      as_MonitorExit()     { return NULL; }

   virtual Intrinsic*        as_Intrinsic()       { return NULL; }

   virtual BlockBegin*       as_BlockBegin()      { return NULL; }

   virtual BlockEnd*         as_BlockEnd()        { return NULL; }

   virtual Goto*             as_Goto()            { return NULL; }

   virtual If*               as_If()              { return NULL; }

   virtual IfInstanceOf*     as_IfInstanceOf()    { return NULL; }

   virtual TableSwitch*      as_TableSwitch()     { return NULL; }

   virtual LookupSwitch*     as_LookupSwitch()    { return NULL; }

   virtual Return*           as_Return()          { return NULL; }

   virtual Throw*            as_Throw()           { return NULL; }

   virtual Base*             as_Base()            { return NULL; }

   virtual RoundFP*          as_RoundFP()         { return NULL; }

   virtual ExceptionObject*  as_ExceptionObject() { return NULL; }

   virtual UnsafeOp*         as_UnsafeOp()        { return NULL; }

   virtual void visit(InstructionVisitor* v)      = 0;

   virtual bool can_trap() const                  { return false; }

   virtual void input_values_do(ValueVisitor* f)   = 0;

   virtual void state_values_do(ValueVisitor* f);

   virtual void other_values_do(ValueVisitor* f)   { /* usually no other - override on demand */ }

           void       values_do(ValueVisitor* f)   { input_values_do(f); state_values_do(f); other_values_do(f); }

   virtual ciType* exact_type() const             { return NULL; }

   virtual ciType* declared_type() const          { return NULL; }

   // hashing

   virtual const char* name() const               = 0;

   HASHING1(Instruction, false, id())             // hashing disabled by default

   // debugging

   static void check_state(ValueStack* state)     PRODUCT_RETURN;

   void print()                                   PRODUCT_RETURN;

   void print_line()                              PRODUCT_RETURN;

   void print(InstructionPrinter& ip)             PRODUCT_RETURN;

 };

 // The following macros are used to define base (i.e., non-leaf)

 // and leaf instruction classes. They define class-name related

 // generic functionality in one place.

 #define BASE(class_name, super_class_name)       \

   class class_name: public super_class_name {    \

    public:                                       \

     virtual class_name* as_##class_name()        { return this; }              \

 #define LEAF(class_name, super_class_name)       \

   BASE(class_name, super_class_name)             \

    public:                                       \

     virtual const char* name() const             { return #class_name; }       \

     virtual void visit(InstructionVisitor* v)    { v->do_##class_name(this); } \

 // Debugging support

 #ifdef ASSERT

 class AssertValues: public ValueVisitor {

   void visit(Value* x)             { assert((*x) != NULL, "value must exist"); }

 };

   #define ASSERT_VALUES                          { AssertValues assert_value; values_do(&assert_value); }

 #else

   #define ASSERT_VALUES

 #endif // ASSERT

 // A Phi is a phi function in the sense of SSA form. It stands for

 // the value of a local variable at the beginning of a join block.

 // A Phi consists of n operands, one for every incoming branch.

 LEAF(Phi, Instruction)

  private:

   BlockBegin* _block;    // the block to which the phi function belongs

   int         _pf_flags; // the flags of the phi function

   int         _index;    // to value on operand stack (index < 0) or to local

  public:

   // creation

   Phi(ValueType* type, BlockBegin* b, int index)

   : Instruction(type->base())

   , _pf_flags(0)

   , _block(b)

   , _index(index)

   {

     if (type->is_illegal()) {

       make_illegal();

     }

   }

   // flags

   enum Flag {

     no_flag         = 0,

     visited         = 1 << 0,

     cannot_simplify = 1 << 1

   };

   // accessors

   bool  is_local() const          { return _index >= 0; }

   bool  is_on_stack() const       { return !is_local(); }

   int   local_index() const       { assert(is_local(), ""); return _index; }

   int   stack_index() const       { assert(is_on_stack(), ""); return -(_index+1); }

   Value operand_at(int i) const;

   int   operand_count() const;

   BlockBegin* block() const       { return _block; }

   void   set(Flag f)              { _pf_flags |=  f; }

   void   clear(Flag f)            { _pf_flags &= ~f; }

   bool   is_set(Flag f) const     { return (_pf_flags & f) != 0; }

   // Invalidates phis corresponding to merges of locals of two different types

   // (these should never be referenced, otherwise the bytecodes are illegal)

   void   make_illegal() {

     set(cannot_simplify);

     set_type(illegalType);

   }

   bool is_illegal() const {

     return type()->is_illegal();

   }

   // generic

   virtual void input_values_do(ValueVisitor* f) {

   }

 };

 // A local is a placeholder for an incoming argument to a function call.

 LEAF(Local, Instruction)

  private:

   int      _java_index;                          // the local index within the method to which the local belongs

  public:

   // creation

   Local(ValueType* type, int index)

     : Instruction(type)

     , _java_index(index)

   {}

   // accessors

   int java_index() const                         { return _java_index; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { /* no values */ }

 };

 LEAF(Constant, Instruction)

  public:

   // creation

   Constant(ValueType* type):

       Instruction(type, NULL, true)

   {

     assert(type->is_constant(), "must be a constant");

   }

   Constant(ValueType* type, ValueStack* state_before):

     Instruction(type, state_before, true)

   {

     assert(state_before != NULL, "only used for constants which need patching");

     assert(type->is_constant(), "must be a constant");

     // since it's patching it needs to be pinned

     pin();

   }

   virtual bool can_trap() const                  { return state_before() != NULL; }

   virtual void input_values_do(ValueVisitor* f)   { /* no values */ }

   virtual intx hash() const;

   virtual bool is_equal(Value v) const;

   virtual BlockBegin* compare(Instruction::Condition condition, Value right,

                               BlockBegin* true_sux, BlockBegin* false_sux);

 };

 BASE(AccessField, Instruction)

  private:

   Value       _obj;

   int         _offset;

   ciField*    _field;

   NullCheck*  _explicit_null_check;              // For explicit null check elimination

  public:

   // creation

   AccessField(Value obj, int offset, ciField* field, bool is_static,

               ValueStack* state_before, bool is_loaded, bool is_initialized)

   : Instruction(as_ValueType(field->type()->basic_type()), state_before)

   , _obj(obj)

   , _offset(offset)

   , _field(field)

   , _explicit_null_check(NULL)

   {

     set_needs_null_check(!is_static);

     set_flag(IsLoadedFlag, is_loaded);

     set_flag(IsInitializedFlag, is_initialized);

     set_flag(IsStaticFlag, is_static);

     ASSERT_VALUES

       if (!is_loaded || (PatchALot && !field->is_volatile())) {

       // need to patch if the holder wasn't loaded or we're testing

       // using PatchALot.  Don't allow PatchALot for fields which are

       // known to be volatile they aren't patchable.

       set_flag(NeedsPatchingFlag, true);

     }

     // pin of all instructions with memory access

     pin();

   }

   // accessors

   Value obj() const                              { return _obj; }

   int offset() const                             { return _offset; }

   ciField* field() const                         { return _field; }

   BasicType field_type() const                   { return _field->type()->basic_type(); }

   bool is_static() const                         { return check_flag(IsStaticFlag); }

   bool is_loaded() const                         { return check_flag(IsLoadedFlag); }

   bool is_initialized() const                    { return check_flag(IsInitializedFlag); }

   NullCheck* explicit_null_check() const         { return _explicit_null_check; }

   bool needs_patching() const                    { return check_flag(NeedsPatchingFlag); }

   // manipulation

   // Under certain circumstances, if a previous NullCheck instruction

   // proved the target object non-null, we can eliminate the explicit

   // null check and do an implicit one, simply specifying the debug

   // information from the NullCheck. This field should only be consulted

   // if needs_null_check() is true.

   void set_explicit_null_check(NullCheck* check) { _explicit_null_check = check; }

   // generic

   virtual bool can_trap() const                  { return needs_null_check() || needs_patching(); }

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_obj); }

 };

 LEAF(LoadField, AccessField)

  public:

   // creation

   LoadField(Value obj, int offset, ciField* field, bool is_static,

             ValueStack* state_before, bool is_loaded, bool is_initialized)

   : AccessField(obj, offset, field, is_static, state_before, is_loaded, is_initialized)

   {}

   ciType* declared_type() const;

   ciType* exact_type() const;

   // generic

   HASHING2(LoadField, is_loaded() && !field()->is_volatile(), obj()->subst(), offset())  // cannot be eliminated if not yet loaded or if volatile

 };

 LEAF(StoreField, AccessField)

  private:

   Value _value;

  public:

   // creation

   StoreField(Value obj, int offset, ciField* field, Value value, bool is_static,

              ValueStack* state_before, bool is_loaded, bool is_initialized)

   : AccessField(obj, offset, field, is_static, state_before, is_loaded, is_initialized)

   , _value(value)

   {

     set_flag(NeedsWriteBarrierFlag, as_ValueType(field_type())->is_object());

     ASSERT_VALUES

     pin();

   }

   // accessors

   Value value() const                            { return _value; }

   bool needs_write_barrier() const               { return check_flag(NeedsWriteBarrierFlag); }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { AccessField::input_values_do(f); f->visit(&_value); }

 };

 BASE(AccessArray, Instruction)

  private:

   Value       _array;

  public:

   // creation

   AccessArray(ValueType* type, Value array, ValueStack* state_before)

   : Instruction(type, state_before)

   , _array(array)

   {

     set_needs_null_check(true);

     ASSERT_VALUES

     pin(); // instruction with side effect (null exception or range check throwing)

   }

   Value array() const                            { return _array; }

   // generic

   virtual bool can_trap() const                  { return needs_null_check(); }

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_array); }

 };

 LEAF(ArrayLength, AccessArray)

  private:

   NullCheck*  _explicit_null_check;              // For explicit null check elimination

  public:

   // creation

   ArrayLength(Value array, ValueStack* state_before)

   : AccessArray(intType, array, state_before)

   , _explicit_null_check(NULL) {}

   // accessors

   NullCheck* explicit_null_check() const         { return _explicit_null_check; }

   // setters

   // See LoadField::set_explicit_null_check for documentation

   void set_explicit_null_check(NullCheck* check) { _explicit_null_check = check; }

   // generic

   HASHING1(ArrayLength, true, array()->subst())

 };

 BASE(AccessIndexed, AccessArray)

  private:

   Value     _index;

   Value     _length;

   BasicType _elt_type;

  public:

   // creation

   AccessIndexed(Value array, Value index, Value length, BasicType elt_type, ValueStack* state_before)

   : AccessArray(as_ValueType(elt_type), array, state_before)

   , _index(index)

   , _length(length)

   , _elt_type(elt_type)

   {

     ASSERT_VALUES

   }

   // accessors

   Value index() const                            { return _index; }

   Value length() const                           { return _length; }

   BasicType elt_type() const                     { return _elt_type; }

   // perform elimination of range checks involving constants

   bool compute_needs_range_check();

   // generic

   virtual void input_values_do(ValueVisitor* f)   { AccessArray::input_values_do(f); f->visit(&_index); if (_length != NULL) f->visit(&_length); }

 };

 LEAF(LoadIndexed, AccessIndexed)

  private:

   NullCheck*  _explicit_null_check;              // For explicit null check elimination

  public:

   // creation

   LoadIndexed(Value array, Value index, Value length, BasicType elt_type, ValueStack* state_before)

   : AccessIndexed(array, index, length, elt_type, state_before)

   , _explicit_null_check(NULL) {}

   // accessors

   NullCheck* explicit_null_check() const         { return _explicit_null_check; }

   // setters

   // See LoadField::set_explicit_null_check for documentation

   void set_explicit_null_check(NullCheck* check) { _explicit_null_check = check; }

   ciType* exact_type() const;

   ciType* declared_type() const;

   // generic

   HASHING2(LoadIndexed, true, array()->subst(), index()->subst())

 };

 LEAF(StoreIndexed, AccessIndexed)

  private:

   Value       _value;

   ciMethod* _profiled_method;

   int       _profiled_bci;

  public:

   // creation

   StoreIndexed(Value array, Value index, Value length, BasicType elt_type, Value value, ValueStack* state_before)

   : AccessIndexed(array, index, length, elt_type, state_before)

   , _value(value), _profiled_method(NULL), _profiled_bci(0)

   {

     set_flag(NeedsWriteBarrierFlag, (as_ValueType(elt_type)->is_object()));

     set_flag(NeedsStoreCheckFlag, (as_ValueType(elt_type)->is_object()));

     ASSERT_VALUES

     pin();

   }

   // accessors

   Value value() const                            { return _value; }

   bool needs_write_barrier() const               { return check_flag(NeedsWriteBarrierFlag); }

   bool needs_store_check() const                 { return check_flag(NeedsStoreCheckFlag); }

   // Helpers for methodDataOop profiling

   void set_should_profile(bool value)                { set_flag(ProfileMDOFlag, value); }

   void set_profiled_method(ciMethod* method)         { _profiled_method = method;   }

   void set_profiled_bci(int bci)                     { _profiled_bci = bci;         }

   bool      should_profile() const                   { return check_flag(ProfileMDOFlag); }

   ciMethod* profiled_method() const                  { return _profiled_method;     }

   int       profiled_bci() const                     { return _profiled_bci;        }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { AccessIndexed::input_values_do(f); f->visit(&_value); }

 };

 LEAF(NegateOp, Instruction)

  private:

   Value _x;

  public:

   // creation

   NegateOp(Value x) : Instruction(x->type()->base()), _x(x) {

     ASSERT_VALUES

   }

   // accessors

   Value x() const                                { return _x; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_x); }

 };

 BASE(Op2, Instruction)

  private:

   Bytecodes::Code _op;

   Value           _x;

   Value           _y;

  public:

   // creation

   Op2(ValueType* type, Bytecodes::Code op, Value x, Value y, ValueStack* state_before = NULL)

   : Instruction(type, state_before)

   , _op(op)

   , _x(x)

   , _y(y)

   {

     ASSERT_VALUES

   }

   // accessors

   Bytecodes::Code op() const                     { return _op; }

   Value x() const                                { return _x; }

   Value y() const                                { return _y; }

   // manipulators

   void swap_operands() {

     assert(is_commutative(), "operation must be commutative");

     Value t = _x; _x = _y; _y = t;

   }

   // generic

   virtual bool is_commutative() const            { return false; }

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_x); f->visit(&_y); }

 };

 LEAF(ArithmeticOp, Op2)

  public:

   // creation

   ArithmeticOp(Bytecodes::Code op, Value x, Value y, bool is_strictfp, ValueStack* state_before)

   : Op2(x->type()->meet(y->type()), op, x, y, state_before)

   {

     set_flag(IsStrictfpFlag, is_strictfp);

     if (can_trap()) pin();

   }

   // accessors

   bool        is_strictfp() const                { return check_flag(IsStrictfpFlag); }

   // generic

   virtual bool is_commutative() const;

   virtual bool can_trap() const;

   HASHING3(Op2, true, op(), x()->subst(), y()->subst())

 };

 LEAF(ShiftOp, Op2)

  public:

   // creation

   ShiftOp(Bytecodes::Code op, Value x, Value s) : Op2(x->type()->base(), op, x, s) {}

   // generic

   HASHING3(Op2, true, op(), x()->subst(), y()->subst())

 };

 LEAF(LogicOp, Op2)

  public:

   // creation

   LogicOp(Bytecodes::Code op, Value x, Value y) : Op2(x->type()->meet(y->type()), op, x, y) {}

   // generic

   virtual bool is_commutative() const;

   HASHING3(Op2, true, op(), x()->subst(), y()->subst())

 };

 LEAF(CompareOp, Op2)

  public:

   // creation

   CompareOp(Bytecodes::Code op, Value x, Value y, ValueStack* state_before)

   : Op2(intType, op, x, y, state_before)

   {}

   // generic

   HASHING3(Op2, true, op(), x()->subst(), y()->subst())

 };

 LEAF(IfOp, Op2)

  private:

   Value _tval;

   Value _fval;

  public:

   // creation

   IfOp(Value x, Condition cond, Value y, Value tval, Value fval)

   : Op2(tval->type()->meet(fval->type()), (Bytecodes::Code)cond, x, y)

   , _tval(tval)

   , _fval(fval)

   {

     ASSERT_VALUES

     assert(tval->type()->tag() == fval->type()->tag(), "types must match");

   }

   // accessors

   virtual bool is_commutative() const;

   Bytecodes::Code op() const                     { ShouldNotCallThis(); return Bytecodes::_illegal; }

   Condition cond() const                         { return (Condition)Op2::op(); }

   Value tval() const                             { return _tval; }

   Value fval() const                             { return _fval; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { Op2::input_values_do(f); f->visit(&_tval); f->visit(&_fval); }

 };

 LEAF(Convert, Instruction)

  private:

   Bytecodes::Code _op;

   Value           _value;

  public:

   // creation

   Convert(Bytecodes::Code op, Value value, ValueType* to_type) : Instruction(to_type), _op(op), _value(value) {

     ASSERT_VALUES

   }

   // accessors

   Bytecodes::Code op() const                     { return _op; }

   Value value() const                            { return _value; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_value); }

   HASHING2(Convert, true, op(), value()->subst())

 };

 LEAF(NullCheck, Instruction)

  private:

   Value       _obj;

  public:

   // creation

   NullCheck(Value obj, ValueStack* state_before)

   : Instruction(obj->type()->base(), state_before)

   , _obj(obj)

   {

     ASSERT_VALUES

     set_can_trap(true);

     assert(_obj->type()->is_object(), "null check must be applied to objects only");

     pin(Instruction::PinExplicitNullCheck);

   }

   // accessors

   Value obj() const                              { return _obj; }

   // setters

   void set_can_trap(bool can_trap)               { set_flag(CanTrapFlag, can_trap); }

   // generic

   virtual bool can_trap() const                  { return check_flag(CanTrapFlag); /* null-check elimination sets to false */ }

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_obj); }

   HASHING1(NullCheck, true, obj()->subst())

 };

 BASE(StateSplit, Instruction)

  private:

   ValueStack* _state;

  protected:

   static void substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block);

  public:

   // creation

   StateSplit(ValueType* type, ValueStack* state_before = NULL)

   : Instruction(type, state_before)

   , _state(NULL)

   {

     pin(PinStateSplitConstructor);

   }

   // accessors

   ValueStack* state() const                      { return _state; }

   IRScope* scope() const;                        // the state's scope

   // manipulation

   void set_state(ValueStack* state)              { assert(_state == NULL, "overwriting existing state"); check_state(state); _state = state; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { /* no values */ }

   virtual void state_values_do(ValueVisitor* f);

 };

 LEAF(Invoke, StateSplit)

  private:

   Bytecodes::Code _code;

   Value           _recv;

   Values*         _args;

   BasicTypeList*  _signature;

   int             _vtable_index;

   ciMethod*       _target;

  public:

   // creation

   Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,

          int vtable_index, ciMethod* target, ValueStack* state_before);

   // accessors

   Bytecodes::Code code() const                   { return _code; }

   Value receiver() const                         { return _recv; }

   bool has_receiver() const                      { return receiver() != NULL; }

   int number_of_arguments() const                { return _args->length(); }

   Value argument_at(int i) const                 { return _args->at(i); }

   int vtable_index() const                       { return _vtable_index; }

   BasicTypeList* signature() const               { return _signature; }

   ciMethod* target() const                       { return _target; }

   // Returns false if target is not loaded

   bool target_is_final() const                   { return check_flag(TargetIsFinalFlag); }

   bool target_is_loaded() const                  { return check_flag(TargetIsLoadedFlag); }

   // Returns false if target is not loaded

   bool target_is_strictfp() const                { return check_flag(TargetIsStrictfpFlag); }

   // JSR 292 support

   bool is_invokedynamic() const                  { return code() == Bytecodes::_invokedynamic; }

   virtual bool needs_exception_state() const     { return false; }

   // generic

   virtual bool can_trap() const                  { return true; }

   virtual void input_values_do(ValueVisitor* f) {

     StateSplit::input_values_do(f);

     if (has_receiver()) f->visit(&_recv);

     for (int i = 0; i < _args->length(); i++) f->visit(_args->adr_at(i));

   }

   virtual void state_values_do(ValueVisitor *f);

 };

 LEAF(NewInstance, StateSplit)

  private:

   ciInstanceKlass* _klass;

  public:

   // creation

   NewInstance(ciInstanceKlass* klass, ValueStack* state_before)

   : StateSplit(instanceType, state_before)

   , _klass(klass)

   {}

   // accessors

   ciInstanceKlass* klass() const                 { return _klass; }

   virtual bool needs_exception_state() const     { return false; }

   // generic

   virtual bool can_trap() const                  { return true; }

   ciType* exact_type() const;

 };

 BASE(NewArray, StateSplit)

  private:

   Value       _length;

  public:

   // creation

   NewArray(Value length, ValueStack* state_before)

   : StateSplit(objectType, state_before)

   , _length(length)

   {

     // Do not ASSERT_VALUES since length is NULL for NewMultiArray

   }

   // accessors

   Value length() const                           { return _length; }

   virtual bool needs_exception_state() const     { return false; }

   // generic

   virtual bool can_trap() const                  { return true; }

   virtual void input_values_do(ValueVisitor* f)   { StateSplit::input_values_do(f); f->visit(&_length); }

 };

 LEAF(NewTypeArray, NewArray)

  private:

   BasicType _elt_type;

  public:

   // creation

   NewTypeArray(Value length, BasicType elt_type, ValueStack* state_before)

   : NewArray(length, state_before)

   , _elt_type(elt_type)

   {}

   // accessors

   BasicType elt_type() const                     { return _elt_type; }

   ciType* exact_type() const;

 };

 LEAF(NewObjectArray, NewArray)

  private:

   ciKlass* _klass;

  public:

   // creation

   NewObjectArray(ciKlass* klass, Value length, ValueStack* state_before) : NewArray(length, state_before), _klass(klass) {}

   // accessors

   ciKlass* klass() const                         { return _klass; }

   ciType* exact_type() const;

 };

 LEAF(NewMultiArray, NewArray)

  private:

   ciKlass* _klass;

   Values*  _dims;

  public:

   // creation

   NewMultiArray(ciKlass* klass, Values* dims, ValueStack* state_before) : NewArray(NULL, state_before), _klass(klass), _dims(dims) {

     ASSERT_VALUES

   }

   // accessors

   ciKlass* klass() const                         { return _klass; }

   Values* dims() const                           { return _dims; }

   int rank() const                               { return dims()->length(); }

   // generic

   virtual void input_values_do(ValueVisitor* f) {

     // NOTE: we do not call NewArray::input_values_do since "length"

     // is meaningless for a multi-dimensional array; passing the

     // zeroth element down to NewArray as its length is a bad idea

     // since there will be a copy in the "dims" array which doesn't

     // get updated, and the value must not be traversed twice. Was bug

     // - kbr 4/10/2001

     StateSplit::input_values_do(f);

     for (int i = 0; i < _dims->length(); i++) f->visit(_dims->adr_at(i));

   }

 };

 BASE(TypeCheck, StateSplit)

  private:

   ciKlass*    _klass;

   Value       _obj;

   ciMethod* _profiled_method;

   int       _profiled_bci;

  public:

   // creation

   TypeCheck(ciKlass* klass, Value obj, ValueType* type, ValueStack* state_before)

   : StateSplit(type, state_before), _klass(klass), _obj(obj),

     _profiled_method(NULL), _profiled_bci(0) {

     ASSERT_VALUES

     set_direct_compare(false);

   }

   // accessors

   ciKlass* klass() const                         { return _klass; }

   Value obj() const                              { return _obj; }

   bool is_loaded() const                         { return klass() != NULL; }

   bool direct_compare() const                    { return check_flag(DirectCompareFlag); }

   // manipulation

   void set_direct_compare(bool flag)             { set_flag(DirectCompareFlag, flag); }

   // generic

   virtual bool can_trap() const                  { return true; }

   virtual void input_values_do(ValueVisitor* f)   { StateSplit::input_values_do(f); f->visit(&_obj); }

   // Helpers for methodDataOop profiling

   void set_should_profile(bool value)                { set_flag(ProfileMDOFlag, value); }

   void set_profiled_method(ciMethod* method)         { _profiled_method = method;   }

   void set_profiled_bci(int bci)                     { _profiled_bci = bci;         }

   bool      should_profile() const                   { return check_flag(ProfileMDOFlag); }

   ciMethod* profiled_method() const                  { return _profiled_method;     }

   int       profiled_bci() const                     { return _profiled_bci;        }

 };

 LEAF(CheckCast, TypeCheck)

  public:

   // creation

   CheckCast(ciKlass* klass, Value obj, ValueStack* state_before)

   : TypeCheck(klass, obj, objectType, state_before) {}

   void set_incompatible_class_change_check() {

     set_flag(ThrowIncompatibleClassChangeErrorFlag, true);

   }

   bool is_incompatible_class_change_check() const {

     return check_flag(ThrowIncompatibleClassChangeErrorFlag);

   }

   ciType* declared_type() const;

   ciType* exact_type() const;

 };

 LEAF(InstanceOf, TypeCheck)

  public:

   // creation

   InstanceOf(ciKlass* klass, Value obj, ValueStack* state_before) : TypeCheck(klass, obj, intType, state_before) {}

   virtual bool needs_exception_state() const     { return false; }

 };

 BASE(AccessMonitor, StateSplit)

  private:

   Value       _obj;

   int         _monitor_no;

  public:

   // creation

   AccessMonitor(Value obj, int monitor_no, ValueStack* state_before = NULL)

   : StateSplit(illegalType, state_before)

   , _obj(obj)

   , _monitor_no(monitor_no)

   {

     set_needs_null_check(true);

     ASSERT_VALUES

   }

   // accessors

   Value obj() const                              { return _obj; }

   int monitor_no() const                         { return _monitor_no; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { StateSplit::input_values_do(f); f->visit(&_obj); }

 };

 LEAF(MonitorEnter, AccessMonitor)

  public:

   // creation

   MonitorEnter(Value obj, int monitor_no, ValueStack* state_before)

   : AccessMonitor(obj, monitor_no, state_before)

   {

     ASSERT_VALUES

   }

   // generic

   virtual bool can_trap() const                  { return true; }

 };

 LEAF(MonitorExit, AccessMonitor)

  public:

   // creation

   MonitorExit(Value obj, int monitor_no)

   : AccessMonitor(obj, monitor_no, NULL)

   {

     ASSERT_VALUES

   }

 };

 LEAF(Intrinsic, StateSplit)

  private:

   vmIntrinsics::ID _id;

   Values*          _args;

   Value            _recv;

  public:

   // preserves_state can be set to true for Intrinsics

   // which are guaranteed to preserve register state across any slow

   // cases; setting it to true does not mean that the Intrinsic can

   // not trap, only that if we continue execution in the same basic

   // block after the Intrinsic, all of the registers are intact. This

   // allows load elimination and common expression elimination to be

   // performed across the Intrinsic.  The default value is false.

   Intrinsic(ValueType* type,

             vmIntrinsics::ID id,

             Values* args,

             bool has_receiver,

             ValueStack* state_before,

             bool preserves_state,

             bool cantrap = true)

   : StateSplit(type, state_before)

   , _id(id)

   , _args(args)

   , _recv(NULL)

   {

     assert(args != NULL, "args must exist");

     ASSERT_VALUES

     set_flag(PreservesStateFlag, preserves_state);

     set_flag(CanTrapFlag,        cantrap);

     if (has_receiver) {

       _recv = argument_at(0);

     }

     set_needs_null_check(has_receiver);

     // some intrinsics can't trap, so don't force them to be pinned

     if (!can_trap()) {

       unpin(PinStateSplitConstructor);

     }

   }

   // accessors

   vmIntrinsics::ID id() const                    { return _id; }

   int number_of_arguments() const                { return _args->length(); }

   Value argument_at(int i) const                 { return _args->at(i); }

   bool has_receiver() const                      { return (_recv != NULL); }

   Value receiver() const                         { assert(has_receiver(), "must have receiver"); return _recv; }

   bool preserves_state() const                   { return check_flag(PreservesStateFlag); }

   // generic

   virtual bool can_trap() const                  { return check_flag(CanTrapFlag); }

   virtual void input_values_do(ValueVisitor* f) {

     StateSplit::input_values_do(f);

     for (int i = 0; i < _args->length(); i++) f->visit(_args->adr_at(i));

   }

 };

 class LIR_List;

 LEAF(BlockBegin, StateSplit)

  private:

   int        _block_id;                          // the unique block id

   int        _bci;                               // start-bci of block

   int        _depth_first_number;                // number of this block in a depth-first ordering

   int        _linear_scan_number;                // number of this block in linear-scan ordering

   int        _loop_depth;                        // the loop nesting level of this block

   int        _loop_index;                        // number of the innermost loop of this block

   int        _flags;                             // the flags associated with this block

   // fields used by BlockListBuilder

   int        _total_preds;                       // number of predecessors found by BlockListBuilder

   BitMap     _stores_to_locals;                  // bit is set when a local variable is stored in the block

   // SSA specific fields: (factor out later)

   BlockList   _successors;                       // the successors of this block

   BlockList   _predecessors;                     // the predecessors of this block

   BlockBegin* _dominator;                        // the dominator of this block

   // SSA specific ends

   BlockEnd*  _end;                               // the last instruction of this block

   BlockList  _exception_handlers;                // the exception handlers potentially invoked by this block

   ValueStackStack* _exception_states;            // only for xhandler entries: states of all instructions that have an edge to this xhandler

   int        _exception_handler_pco;             // if this block is the start of an exception handler,

                                                  // this records the PC offset in the assembly code of the

                                                  // first instruction in this block

   Label      _label;                             // the label associated with this block

   LIR_List*  _lir;                               // the low level intermediate representation for this block

   BitMap      _live_in;                          // set of live LIR_Opr registers at entry to this block

   BitMap      _live_out;                         // set of live LIR_Opr registers at exit from this block

   BitMap      _live_gen;                         // set of registers used before any redefinition in this block

   BitMap      _live_kill;                        // set of registers defined in this block

   BitMap      _fpu_register_usage;

   intArray*   _fpu_stack_state;                  // For x86 FPU code generation with UseLinearScan

   int         _first_lir_instruction_id;         // ID of first LIR instruction in this block

   int         _last_lir_instruction_id;          // ID of last LIR instruction in this block

   void iterate_preorder (boolArray& mark, BlockClosure* closure);

   void iterate_postorder(boolArray& mark, BlockClosure* closure);

   friend class SuxAndWeightAdjuster;

  public:

    void* operator new(size_t size) {

     Compilation* c = Compilation::current();

     void* res = c->arena()->Amalloc(size);

     ((BlockBegin*)res)->_id = c->get_next_id();

     ((BlockBegin*)res)->_block_id = c->get_next_block_id();

     return res;

   }

   // initialization/counting

   static int  number_of_blocks() {

     return Compilation::current()->number_of_blocks();

   }

   // creation

   BlockBegin(int bci)

   : StateSplit(illegalType)

   , _bci(bci)

   , _depth_first_number(-1)

   , _linear_scan_number(-1)

   , _loop_depth(0)

   , _flags(0)

   , _dominator(NULL)

   , _end(NULL)

   , _predecessors(2)

   , _successors(2)

   , _exception_handlers(1)

   , _exception_states(NULL)

   , _exception_handler_pco(-1)

   , _lir(NULL)

   , _loop_index(-1)

   , _live_in()

   , _live_out()

   , _live_gen()

   , _live_kill()

   , _fpu_register_usage()

   , _fpu_stack_state(NULL)

   , _first_lir_instruction_id(-1)

   , _last_lir_instruction_id(-1)

   , _total_preds(0)

   , _stores_to_locals()

   {

 #ifndef PRODUCT

     set_printable_bci(bci);

 #endif

   }

   // accessors

   int block_id() const                           { return _block_id; }

   int bci() const                                { return _bci; }

   BlockList* successors()                        { return &_successors; }

   BlockBegin* dominator() const                  { return _dominator; }

   int loop_depth() const                         { return _loop_depth; }

   int depth_first_number() const                 { return _depth_first_number; }

   int linear_scan_number() const                 { return _linear_scan_number; }

   BlockEnd* end() const                          { return _end; }

   Label* label()                                 { return &_label; }

   LIR_List* lir() const                          { return _lir; }

   int exception_handler_pco() const              { return _exception_handler_pco; }

   BitMap& live_in()                              { return _live_in;        }

   BitMap& live_out()                             { return _live_out;       }

   BitMap& live_gen()                             { return _live_gen;       }

   BitMap& live_kill()                            { return _live_kill;      }

   BitMap& fpu_register_usage()                   { return _fpu_register_usage; }

   intArray* fpu_stack_state() const              { return _fpu_stack_state;    }

   int first_lir_instruction_id() const           { return _first_lir_instruction_id; }

   int last_lir_instruction_id() const            { return _last_lir_instruction_id; }

   int total_preds() const                        { return _total_preds; }

   BitMap& stores_to_locals()                     { return _stores_to_locals; }

   // manipulation

   void set_dominator(BlockBegin* dom)            { _dominator = dom; }

   void set_loop_depth(int d)                     { _loop_depth = d; }

   void set_depth_first_number(int dfn)           { _depth_first_number = dfn; }

   void set_linear_scan_number(int lsn)           { _linear_scan_number = lsn; }

   void set_end(BlockEnd* end);

   void disconnect_from_graph();

   static void disconnect_edge(BlockBegin* from, BlockBegin* to);

   BlockBegin* insert_block_between(BlockBegin* sux);

   void substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux);

   void set_lir(LIR_List* lir)                    { _lir = lir; }

   void set_exception_handler_pco(int pco)        { _exception_handler_pco = pco; }

   void set_live_in       (BitMap map)            { _live_in = map;        }

   void set_live_out      (BitMap map)            { _live_out = map;       }

   void set_live_gen      (BitMap map)            { _live_gen = map;       }

   void set_live_kill     (BitMap map)            { _live_kill = map;      }

   void set_fpu_register_usage(BitMap map)        { _fpu_register_usage = map; }

   void set_fpu_stack_state(intArray* state)      { _fpu_stack_state = state;  }

   void set_first_lir_instruction_id(int id)      { _first_lir_instruction_id = id;  }

   void set_last_lir_instruction_id(int id)       { _last_lir_instruction_id = id;  }

   void increment_total_preds(int n = 1)          { _total_preds += n; }

   void init_stores_to_locals(int locals_count)   { _stores_to_locals = BitMap(locals_count); _stores_to_locals.clear(); }

   // generic

   virtual void state_values_do(ValueVisitor* f);

   // successors and predecessors

   int number_of_sux() const;

   BlockBegin* sux_at(int i) const;

   void add_successor(BlockBegin* sux);

   void remove_successor(BlockBegin* pred);

   bool is_successor(BlockBegin* sux) const       { return _successors.contains(sux); }

   void add_predecessor(BlockBegin* pred);

   void remove_predecessor(BlockBegin* pred);

   bool is_predecessor(BlockBegin* pred) const    { return _predecessors.contains(pred); }

   int number_of_preds() const                    { return _predecessors.length(); }

   BlockBegin* pred_at(int i) const               { return _predecessors[i]; }

   // exception handlers potentially invoked by this block

   void add_exception_handler(BlockBegin* b);

   bool is_exception_handler(BlockBegin* b) const { return _exception_handlers.contains(b); }

   int  number_of_exception_handlers() const      { return _exception_handlers.length(); }

   BlockBegin* exception_handler_at(int i) const  { return _exception_handlers.at(i); }

   // states of the instructions that have an edge to this exception handler

   int number_of_exception_states()               { assert(is_set(exception_entry_flag), "only for xhandlers"); return _exception_states == NULL ? 0 : _exception_states->length(); }

   ValueStack* exception_state_at(int idx) const  { assert(is_set(exception_entry_flag), "only for xhandlers"); return _exception_states->at(idx); }

   int add_exception_state(ValueStack* state);

   // flags

   enum Flag {

     no_flag                       = 0,

     std_entry_flag                = 1 << 0,

     osr_entry_flag                = 1 << 1,

     exception_entry_flag          = 1 << 2,

     subroutine_entry_flag         = 1 << 3,

     backward_branch_target_flag   = 1 << 4,

     is_on_work_list_flag          = 1 << 5,

     was_visited_flag              = 1 << 6,

     parser_loop_header_flag       = 1 << 7,  // set by parser to identify blocks where phi functions can not be created on demand

     critical_edge_split_flag      = 1 << 8, // set for all blocks that are introduced when critical edges are split

     linear_scan_loop_header_flag  = 1 << 9, // set during loop-detection for LinearScan

     linear_scan_loop_end_flag     = 1 << 10  // set during loop-detection for LinearScan

   };

   void set(Flag f)                               { _flags |= f; }

   void clear(Flag f)                             { _flags &= ~f; }

   bool is_set(Flag f) const                      { return (_flags & f) != 0; }

   bool is_entry_block() const {

     const int entry_mask = std_entry_flag | osr_entry_flag | exception_entry_flag;

     return (_flags & entry_mask) != 0;

   }

   // iteration

   void iterate_preorder   (BlockClosure* closure);

   void iterate_postorder  (BlockClosure* closure);

   void block_values_do(ValueVisitor* f);

   // loops

   void set_loop_index(int ix)                    { _loop_index = ix;        }

   int  loop_index() const                        { return _loop_index;      }

   // merging

   bool try_merge(ValueStack* state);             // try to merge states at block begin

   void merge(ValueStack* state)                  { bool b = try_merge(state); assert(b, "merge failed"); }

   // debugging

   void print_block()                             PRODUCT_RETURN;

   void print_block(InstructionPrinter& ip, bool live_only = false) PRODUCT_RETURN;

 };

 BASE(BlockEnd, StateSplit)

  private:

   BlockBegin* _begin;

   BlockList*  _sux;

  protected:

   BlockList* sux() const                         { return _sux; }

   void set_sux(BlockList* sux) {

 #ifdef ASSERT

     assert(sux != NULL, "sux must exist");

     for (int i = sux->length() - 1; i >= 0; i--) assert(sux->at(i) != NULL, "sux must exist");

 #endif

     _sux = sux;

   }

  public:

   // creation

   BlockEnd(ValueType* type, ValueStack* state_before, bool is_safepoint)

   : StateSplit(type, state_before)

   , _begin(NULL)

   , _sux(NULL)

   {

     set_flag(IsSafepointFlag, is_safepoint);

   }

   // accessors

   bool is_safepoint() const                      { return check_flag(IsSafepointFlag); }

   BlockBegin* begin() const                      { return _begin; }

   // manipulation

   void set_begin(BlockBegin* begin);

   // successors

   int number_of_sux() const                      { return _sux != NULL ? _sux->length() : 0; }

   BlockBegin* sux_at(int i) const                { return _sux->at(i); }

   BlockBegin* default_sux() const                { return sux_at(number_of_sux() - 1); }

   BlockBegin** addr_sux_at(int i) const          { return _sux->adr_at(i); }

   int sux_index(BlockBegin* sux) const           { return _sux->find(sux); }

   void substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux);

 };

 LEAF(Goto, BlockEnd)

  public:

   enum Direction {

     none,            // Just a regular goto

     taken, not_taken // Goto produced from If

   };

  private:

   ciMethod*   _profiled_method;

   int         _profiled_bci;

   Direction   _direction;

  public:

   // creation

   Goto(BlockBegin* sux, ValueStack* state_before, bool is_safepoint = false)

     : BlockEnd(illegalType, state_before, is_safepoint)

     , _direction(none)

     , _profiled_method(NULL)

     , _profiled_bci(0) {

     BlockList* s = new BlockList(1);

     s->append(sux);

     set_sux(s);

   }

   Goto(BlockBegin* sux, bool is_safepoint) : BlockEnd(illegalType, NULL, is_safepoint)

                                            , _direction(none)

                                            , _profiled_method(NULL)

                                            , _profiled_bci(0) {

     BlockList* s = new BlockList(1);

     s->append(sux);

     set_sux(s);

   }

   bool should_profile() const                    { return check_flag(ProfileMDOFlag); }

   ciMethod* profiled_method() const              { return _profiled_method; } // set only for profiled branches

   int profiled_bci() const                       { return _profiled_bci; }

   Direction direction() const                    { return _direction; }

   void set_should_profile(bool value)            { set_flag(ProfileMDOFlag, value); }

   void set_profiled_method(ciMethod* method)     { _profiled_method = method; }

   void set_profiled_bci(int bci)                 { _profiled_bci = bci; }

   void set_direction(Direction d)                { _direction = d; }

 };

 LEAF(If, BlockEnd)

  private:

   Value       _x;

   Condition   _cond;

   Value       _y;

   ciMethod*   _profiled_method;

   int         _profiled_bci; // Canonicalizer may alter bci of If node

   bool        _swapped;      // Is the order reversed with respect to the original If in the

                              // bytecode stream?

  public:

   // creation

   // unordered_is_true is valid for float/double compares only

   If(Value x, Condition cond, bool unordered_is_true, Value y, BlockBegin* tsux, BlockBegin* fsux, ValueStack* state_before, bool is_safepoint)

     : BlockEnd(illegalType, state_before, is_safepoint)

   , _x(x)

   , _cond(cond)

   , _y(y)

   , _profiled_method(NULL)

   , _profiled_bci(0)

   , _swapped(false)

   {

     ASSERT_VALUES

     set_flag(UnorderedIsTrueFlag, unordered_is_true);

     assert(x->type()->tag() == y->type()->tag(), "types must match");

     BlockList* s = new BlockList(2);

     s->append(tsux);

     s->append(fsux);

     set_sux(s);

   }

   // accessors

   Value x() const                                { return _x; }

   Condition cond() const                         { return _cond; }

   bool unordered_is_true() const                 { return check_flag(UnorderedIsTrueFlag); }

   Value y() const                                { return _y; }

   BlockBegin* sux_for(bool is_true) const        { return sux_at(is_true ? 0 : 1); }

   BlockBegin* tsux() const                       { return sux_for(true); }

   BlockBegin* fsux() const                       { return sux_for(false); }

   BlockBegin* usux() const                       { return sux_for(unordered_is_true()); }

   bool should_profile() const                    { return check_flag(ProfileMDOFlag); }

   ciMethod* profiled_method() const              { return _profiled_method; } // set only for profiled branches

   int profiled_bci() const                       { return _profiled_bci; }    // set for profiled branches and tiered

   bool is_swapped() const                        { return _swapped; }

   // manipulation

   void swap_operands() {

     Value t = _x; _x = _y; _y = t;

     _cond = mirror(_cond);

   }

   void swap_sux() {

     assert(number_of_sux() == 2, "wrong number of successors");

     BlockList* s = sux();

     BlockBegin* t = s->at(0); s->at_put(0, s->at(1)); s->at_put(1, t);

     _cond = negate(_cond);

     set_flag(UnorderedIsTrueFlag, !check_flag(UnorderedIsTrueFlag));

   }

   void set_should_profile(bool value)             { set_flag(ProfileMDOFlag, value); }

   void set_profiled_method(ciMethod* method)      { _profiled_method = method; }

   void set_profiled_bci(int bci)                  { _profiled_bci = bci;       }

   void set_swapped(bool value)                    { _swapped = value;         }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { BlockEnd::input_values_do(f); f->visit(&_x); f->visit(&_y); }

 };

 LEAF(IfInstanceOf, BlockEnd)

  private:

   ciKlass* _klass;

   Value    _obj;

   bool     _test_is_instance;                    // jump if instance

   int      _instanceof_bci;

  public:

   IfInstanceOf(ciKlass* klass, Value obj, bool test_is_instance, int instanceof_bci, BlockBegin* tsux, BlockBegin* fsux)

   : BlockEnd(illegalType, NULL, false) // temporary set to false

   , _klass(klass)

   , _obj(obj)

   , _test_is_instance(test_is_instance)

   , _instanceof_bci(instanceof_bci)

   {

     ASSERT_VALUES

     assert(instanceof_bci >= 0, "illegal bci");

     BlockList* s = new BlockList(2);

     s->append(tsux);

     s->append(fsux);

     set_sux(s);

   }

   // accessors

   //

   // Note 1: If test_is_instance() is true, IfInstanceOf tests if obj *is* an

   //         instance of klass; otherwise it tests if it is *not* and instance

   //         of klass.

   //

   // Note 2: IfInstanceOf instructions are created by combining an InstanceOf

   //         and an If instruction. The IfInstanceOf bci() corresponds to the

   //         bci that the If would have had; the (this->) instanceof_bci() is

   //         the bci of the original InstanceOf instruction.

   ciKlass* klass() const                         { return _klass; }

   Value obj() const                              { return _obj; }

   int instanceof_bci() const                     { return _instanceof_bci; }

   bool test_is_instance() const                  { return _test_is_instance; }

   BlockBegin* sux_for(bool is_true) const        { return sux_at(is_true ? 0 : 1); }

   BlockBegin* tsux() const                       { return sux_for(true); }

   BlockBegin* fsux() const                       { return sux_for(false); }

   // manipulation

   void swap_sux() {

     assert(number_of_sux() == 2, "wrong number of successors");

     BlockList* s = sux();

     BlockBegin* t = s->at(0); s->at_put(0, s->at(1)); s->at_put(1, t);

     _test_is_instance = !_test_is_instance;

   }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { BlockEnd::input_values_do(f); f->visit(&_obj); }

 };

 BASE(Switch, BlockEnd)

  private:

   Value       _tag;

  public:

   // creation

   Switch(Value tag, BlockList* sux, ValueStack* state_before, bool is_safepoint)

   : BlockEnd(illegalType, state_before, is_safepoint)

   , _tag(tag) {

     ASSERT_VALUES

     set_sux(sux);

   }

   // accessors

   Value tag() const                              { return _tag; }

   int length() const                             { return number_of_sux() - 1; }

   virtual bool needs_exception_state() const     { return false; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { BlockEnd::input_values_do(f); f->visit(&_tag); }

 };

 LEAF(TableSwitch, Switch)

  private:

   int _lo_key;

  public:

   // creation

   TableSwitch(Value tag, BlockList* sux, int lo_key, ValueStack* state_before, bool is_safepoint)

     : Switch(tag, sux, state_before, is_safepoint)

   , _lo_key(lo_key) {}

   // accessors

   int lo_key() const                             { return _lo_key; }

   int hi_key() const                             { return _lo_key + length() - 1; }

 };

 LEAF(LookupSwitch, Switch)

  private:

   intArray* _keys;

  public:

   // creation

   LookupSwitch(Value tag, BlockList* sux, intArray* keys, ValueStack* state_before, bool is_safepoint)

   : Switch(tag, sux, state_before, is_safepoint)

   , _keys(keys) {

     assert(keys != NULL, "keys must exist");

     assert(keys->length() == length(), "sux & keys have incompatible lengths");

   }

   // accessors

   int key_at(int i) const                        { return _keys->at(i); }

 };

 LEAF(Return, BlockEnd)

  private:

   Value _result;

  public:

   // creation

   Return(Value result) :

     BlockEnd(result == NULL ? voidType : result->type()->base(), NULL, true),

     _result(result) {}

   // accessors

   Value result() const                           { return _result; }

   bool has_result() const                        { return result() != NULL; }

   // generic

   virtual void input_values_do(ValueVisitor* f) {

     BlockEnd::input_values_do(f);

     if (has_result()) f->visit(&_result);

   }

 };

 LEAF(Throw, BlockEnd)

  private:

   Value _exception;

  public:

   // creation

   Throw(Value exception, ValueStack* state_before) : BlockEnd(illegalType, state_before, true), _exception(exception) {

     ASSERT_VALUES

   }

   // accessors

   Value exception() const                        { return _exception; }

   // generic

   virtual bool can_trap() const                  { return true; }

   virtual void input_values_do(ValueVisitor* f)   { BlockEnd::input_values_do(f); f->visit(&_exception); }

 };

 LEAF(Base, BlockEnd)

  public:

   // creation

   Base(BlockBegin* std_entry, BlockBegin* osr_entry) : BlockEnd(illegalType, NULL, false) {

     assert(std_entry->is_set(BlockBegin::std_entry_flag), "std entry must be flagged");

     assert(osr_entry == NULL || osr_entry->is_set(BlockBegin::osr_entry_flag), "osr entry must be flagged");

     BlockList* s = new BlockList(2);

     if (osr_entry != NULL) s->append(osr_entry);

     s->append(std_entry); // must be default sux!

     set_sux(s);

   }

   // accessors

   BlockBegin* std_entry() const                  { return default_sux(); }

   BlockBegin* osr_entry() const                  { return number_of_sux() < 2 ? NULL : sux_at(0); }

 };

 LEAF(OsrEntry, Instruction)

  public:

   // creation

 #ifdef _LP64

   OsrEntry() : Instruction(longType) { pin(); }

 #else

   OsrEntry() : Instruction(intType)  { pin(); }

 #endif

   // generic

   virtual void input_values_do(ValueVisitor* f)   { }

 };

 // Models the incoming exception at a catch site

 LEAF(ExceptionObject, Instruction)

  public:

   // creation

   ExceptionObject() : Instruction(objectType) {

     pin();

   }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { }

 };

 // Models needed rounding for floating-point values on Intel.

 // Currently only used to represent rounding of double-precision

 // values stored into local variables, but could be used to model

 // intermediate rounding of single-precision values as well.

 LEAF(RoundFP, Instruction)

  private:

   Value _input;             // floating-point value to be rounded

  public:

   RoundFP(Value input)

   : Instruction(input->type()) // Note: should not be used for constants

   , _input(input)

   {

     ASSERT_VALUES

   }

   // accessors

   Value input() const                            { return _input; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { f->visit(&_input); }

 };

 BASE(UnsafeOp, Instruction)

  private:

   BasicType _basic_type;    // ValueType can not express byte-sized integers

  protected:

   // creation

   UnsafeOp(BasicType basic_type, bool is_put)

   : Instruction(is_put ? voidType : as_ValueType(basic_type))

   , _basic_type(basic_type)

   {

     //Note:  Unsafe ops are not not guaranteed to throw NPE.

     // Convservatively, Unsafe operations must be pinned though we could be

     // looser about this if we wanted to..

     pin();

   }

  public:

   // accessors

   BasicType basic_type()                         { return _basic_type; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { }

 };

 BASE(UnsafeRawOp, UnsafeOp)

  private:

   Value _base;                                   // Base address (a Java long)

   Value _index;                                  // Index if computed by optimizer; initialized to NULL

   int   _log2_scale;                             // Scale factor: 0, 1, 2, or 3.

                                                  // Indicates log2 of number of bytes (1, 2, 4, or 8)

                                                  // to scale index by.

  protected:

   UnsafeRawOp(BasicType basic_type, Value addr, bool is_put)

   : UnsafeOp(basic_type, is_put)

   , _base(addr)

   , _index(NULL)

   , _log2_scale(0)

   {

     // Can not use ASSERT_VALUES because index may be NULL

     assert(addr != NULL && addr->type()->is_long(), "just checking");

   }

   UnsafeRawOp(BasicType basic_type, Value base, Value index, int log2_scale, bool is_put)

   : UnsafeOp(basic_type, is_put)

   , _base(base)

   , _index(index)

   , _log2_scale(log2_scale)

   {

   }

  public:

   // accessors

   Value base()                                   { return _base; }

   Value index()                                  { return _index; }

   bool  has_index()                              { return (_index != NULL); }

   int   log2_scale()                             { return _log2_scale; }

   // setters

   void set_base (Value base)                     { _base  = base; }

   void set_index(Value index)                    { _index = index; }

   void set_log2_scale(int log2_scale)            { _log2_scale = log2_scale; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { UnsafeOp::input_values_do(f);

                                                    f->visit(&_base);

                                                    if (has_index()) f->visit(&_index); }

 };

 LEAF(UnsafeGetRaw, UnsafeRawOp)

  private:

   bool _may_be_unaligned;  // For OSREntry

  public:

   UnsafeGetRaw(BasicType basic_type, Value addr, bool may_be_unaligned)

   : UnsafeRawOp(basic_type, addr, false) {

     _may_be_unaligned = may_be_unaligned;

   }

   UnsafeGetRaw(BasicType basic_type, Value base, Value index, int log2_scale, bool may_be_unaligned)

   : UnsafeRawOp(basic_type, base, index, log2_scale, false) {

     _may_be_unaligned = may_be_unaligned;

   }

   bool may_be_unaligned()                               { return _may_be_unaligned; }

 };

 LEAF(UnsafePutRaw, UnsafeRawOp)

  private:

   Value _value;                                  // Value to be stored

  public:

   UnsafePutRaw(BasicType basic_type, Value addr, Value value)

   : UnsafeRawOp(basic_type, addr, true)

   , _value(value)

   {

     assert(value != NULL, "just checking");

     ASSERT_VALUES

   }

   UnsafePutRaw(BasicType basic_type, Value base, Value index, int log2_scale, Value value)

   : UnsafeRawOp(basic_type, base, index, log2_scale, true)

   , _value(value)

   {

     assert(value != NULL, "just checking");

     ASSERT_VALUES

   }

   // accessors

   Value value()                                  { return _value; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { UnsafeRawOp::input_values_do(f);

                                                    f->visit(&_value); }

 };

 BASE(UnsafeObjectOp, UnsafeOp)

  private:

   Value _object;                                 // Object to be fetched from or mutated

   Value _offset;                                 // Offset within object

   bool  _is_volatile;                            // true if volatile - dl/JSR166

  public:

   UnsafeObjectOp(BasicType basic_type, Value object, Value offset, bool is_put, bool is_volatile)

     : UnsafeOp(basic_type, is_put), _object(object), _offset(offset), _is_volatile(is_volatile)

   {

   }

   // accessors

   Value object()                                 { return _object; }

   Value offset()                                 { return _offset; }

   bool  is_volatile()                            { return _is_volatile; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { UnsafeOp::input_values_do(f);

                                                    f->visit(&_object);

                                                    f->visit(&_offset); }

 };

 LEAF(UnsafeGetObject, UnsafeObjectOp)

  public:

   UnsafeGetObject(BasicType basic_type, Value object, Value offset, bool is_volatile)

   : UnsafeObjectOp(basic_type, object, offset, false, is_volatile)

   {

     ASSERT_VALUES

   }

 };

 LEAF(UnsafePutObject, UnsafeObjectOp)

  private:

   Value _value;                                  // Value to be stored

  public:

   UnsafePutObject(BasicType basic_type, Value object, Value offset, Value value, bool is_volatile)

   : UnsafeObjectOp(basic_type, object, offset, true, is_volatile)

     , _value(value)

   {

     ASSERT_VALUES

   }

   // accessors

   Value value()                                  { return _value; }

   // generic

   virtual void input_values_do(ValueVisitor* f)   { UnsafeObjectOp::input_values_do(f);

                                                    f->visit(&_value); }

 };

 BASE(UnsafePrefetch, UnsafeObjectOp)

  public:

   UnsafePrefetch(Value object, Value offset)

   : UnsafeObjectOp(T_VOID, object, offset, false, false)

   {

   }

 };

 LEAF(UnsafePrefetchRead, UnsafePrefetch)

  public:

   UnsafePrefetchRead(Value object, Value offset)

   : UnsafePrefetch(object, offset)

   {

     ASSERT_VALUES

   }

 };

 LEAF(UnsafePrefetchWrite, UnsafePrefetch)

  public:

   UnsafePrefetchWrite(Value object, Value offset)

   : UnsafePrefetch(object, offset)

   {

     ASSERT_VALUES

   }

 };

 LEAF(ProfileCall, Instruction)

  private:

   ciMethod* _method;

   int       _bci_of_invoke;

   Value     _recv;

   ciKlass*  _known_holder;

  public:

   ProfileCall(ciMethod* method, int bci, Value recv, ciKlass* known_holder)

     : Instruction(voidType)

     , _method(method)

     , _bci_of_invoke(bci)

     , _recv(recv)

     , _known_holder(known_holder)

   {

     // The ProfileCall has side-effects and must occur precisely where located

     pin();

   }

   ciMethod* method()      { return _method; }

   int bci_of_invoke()     { return _bci_of_invoke; }

   Value recv()            { return _recv; }

   ciKlass* known_holder() { return _known_holder; }

   virtual void input_values_do(ValueVisitor* f)   { if (_recv != NULL) f->visit(&_recv); }

 };

 // Use to trip invocation counter of an inlined method

 LEAF(ProfileInvoke, Instruction)

  private:

   ciMethod*   _inlinee;

   ValueStack* _state;

  public:

   ProfileInvoke(ciMethod* inlinee,  ValueStack* state)

     : Instruction(voidType)

     , _inlinee(inlinee)

     , _state(state)

   {

     // The ProfileInvoke has side-effects and must occur precisely where located QQQ???

     pin();

   }

   ciMethod* inlinee()      { return _inlinee; }

   ValueStack* state()      { return _state; }

   virtual void input_values_do(ValueVisitor*)   {}

   virtual void state_values_do(ValueVisitor*);

 };

 class BlockPair: public CompilationResourceObj {

  private:

   BlockBegin* _from;

   BlockBegin* _to;

  public:

   BlockPair(BlockBegin* from, BlockBegin* to): _from(from), _to(to) {}

   BlockBegin* from() const { return _from; }

   BlockBegin* to() const   { return _to;   }

   bool is_same(BlockBegin* from, BlockBegin* to) const { return  _from == from && _to == to; }

   bool is_same(BlockPair* p) const { return  _from == p->from() && _to == p->to(); }

   void set_to(BlockBegin* b)   { _to = b; }

   void set_from(BlockBegin* b) { _from = b; }

 };

 define_array(BlockPairArray, BlockPair*)

 define_stack(BlockPairList, BlockPairArray)

 inline int         BlockBegin::number_of_sux() const            { assert(_end == NULL || _end->number_of_sux() == _successors.length(), "mismatch"); return _successors.length(); }

 inline BlockBegin* BlockBegin::sux_at(int i) const              { assert(_end == NULL || _end->sux_at(i) == _successors.at(i), "mismatch");          return _successors.at(i); }

 inline void        BlockBegin::add_successor(BlockBegin* sux)   { assert(_end == NULL, "Would create mismatch with successors of BlockEnd");         _successors.append(sux); }

 #undef ASSERT_VALUES