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

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  * published by the Free Software Foundation.

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  * 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).

  *

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

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 #ifndef SHARE_VM_OPTO_CFGNODE_HPP

 #define SHARE_VM_OPTO_CFGNODE_HPP

 #include "opto/multnode.hpp"

 #include "opto/node.hpp"

 #include "opto/opcodes.hpp"

 #include "opto/type.hpp"

 // Portions of code courtesy of Clifford Click

 // Optimization - Graph Style

 class Matcher;

 class Node;

 class   RegionNode;

 class   TypeNode;

 class     PhiNode;

 class   GotoNode;

 class   MultiNode;

 class     MultiBranchNode;

 class       IfNode;

 class       PCTableNode;

 class         JumpNode;

 class         CatchNode;

 class       NeverBranchNode;

 class   ProjNode;

 class     CProjNode;

 class       IfTrueNode;

 class       IfFalseNode;

 class       CatchProjNode;

 class     JProjNode;

 class       JumpProjNode;

 class     SCMemProjNode;

 class PhaseIdealLoop;

 //------------------------------RegionNode-------------------------------------

 // The class of RegionNodes, which can be mapped to basic blocks in the

 // program.  Their inputs point to Control sources.  PhiNodes (described

 // below) have an input point to a RegionNode.  Merged data inputs to PhiNodes

 // correspond 1-to-1 with RegionNode inputs.  The zero input of a PhiNode is

 // the RegionNode, and the zero input of the RegionNode is itself.

 class RegionNode : public Node {

 public:

   // Node layout (parallels PhiNode):

   enum { Region,                // Generally points to self.

          Control                // Control arcs are [1..len)

   };

   RegionNode( uint required ) : Node(required) {

     init_class_id(Class_Region);

     init_req(0,this);

   }

   Node* is_copy() const {

     const Node* r = _in[Region];

     if (r == NULL)

       return nonnull_req();

     return NULL;  // not a copy!

   }

   PhiNode* has_phi() const;        // returns an arbitrary phi user, or NULL

   PhiNode* has_unique_phi() const; // returns the unique phi user, or NULL

   // Is this region node unreachable from root?

   bool is_unreachable_region(PhaseGVN *phase) const;

   virtual int Opcode() const;

   virtual bool pinned() const { return (const Node *)in(0) == this; }

   virtual bool  is_CFG   () const { return true; }

   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash

   virtual bool depends_only_on_test() const { return false; }

   virtual const Type *bottom_type() const { return Type::CONTROL; }

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual Node *Identity( PhaseTransform *phase );

   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   virtual const RegMask &out_RegMask() const;

   bool try_clean_mem_phi(PhaseGVN *phase);

 };

 //------------------------------JProjNode--------------------------------------

 // jump projection for node that produces multiple control-flow paths

 class JProjNode : public ProjNode {

  public:

   JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {}

   virtual int Opcode() const;

   virtual bool  is_CFG() const { return true; }

   virtual uint  hash() const { return NO_HASH; }  // CFG nodes do not hash

   virtual const Node* is_block_proj() const { return in(0); }

   virtual const RegMask& out_RegMask() const;

   virtual uint  ideal_reg() const { return 0; }

 };

 //------------------------------PhiNode----------------------------------------

 // PhiNodes merge values from different Control paths.  Slot 0 points to the

 // controlling RegionNode.  Other slots map 1-for-1 with incoming control flow

 // paths to the RegionNode.  For speed reasons (to avoid another pass) we

 // can turn PhiNodes into copys in-place by NULL'ing out their RegionNode

 // input in slot 0.

 class PhiNode : public TypeNode {

   const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes.

   const int _inst_id;     // Instance id of the memory slice.

   const int _inst_index;  // Alias index of the instance memory slice.

   // Array elements references have the same alias_idx but different offset.

   const int _inst_offset; // Offset of the instance memory slice.

   // Size is bigger to hold the _adr_type field.

   virtual uint hash() const;    // Check the type

   virtual uint cmp( const Node &n ) const;

   virtual uint size_of() const { return sizeof(*this); }

   // Determine if CMoveNode::is_cmove_id can be used at this join point.

   Node* is_cmove_id(PhaseTransform* phase, int true_path);

 public:

   // Node layout (parallels RegionNode):

   enum { Region,                // Control input is the Phi's region.

          Input                  // Input values are [1..len)

   };

   PhiNode( Node *r, const Type *t, const TypePtr* at = NULL,

            const int iid = TypeOopPtr::InstanceTop,

            const int iidx = Compile::AliasIdxTop,

            const int ioffs = Type::OffsetTop )

     : TypeNode(t,r->req()),

       _adr_type(at),

       _inst_id(iid),

       _inst_index(iidx),

       _inst_offset(ioffs)

   {

     init_class_id(Class_Phi);

     init_req(0, r);

     verify_adr_type();

   }

   // create a new phi with in edges matching r and set (initially) to x

   static PhiNode* make( Node* r, Node* x );

   // extra type arguments override the new phi's bottom_type and adr_type

   static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL );

   // create a new phi with narrowed memory type

   PhiNode* slice_memory(const TypePtr* adr_type) const;

   PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;

   // like make(r, x), but does not initialize the in edges to x

   static PhiNode* make_blank( Node* r, Node* x );

   // Accessors

   RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; }

   Node* is_copy() const {

     // The node is a real phi if _in[0] is a Region node.

     DEBUG_ONLY(const Node* r = _in[Region];)

     assert(r != NULL && r->is_Region(), "Not valid control");

     return NULL;  // not a copy!

   }

   bool is_tripcount() const;

   // Determine a unique non-trivial input, if any.

   // Ignore casts if it helps.  Return NULL on failure.

   Node* unique_input(PhaseTransform *phase);

   // Check for a simple dead loop.

   enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop };

   LoopSafety simple_data_loop_check(Node *in) const;

   // Is it unsafe data loop? It becomes a dead loop if this phi node removed.

   bool is_unsafe_data_reference(Node *in) const;

   int  is_diamond_phi(bool check_control_only = false) const;

   virtual int Opcode() const;

   virtual bool pinned() const { return in(0) != 0; }

   virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; }

   const int inst_id()     const { return _inst_id; }

   const int inst_index()  const { return _inst_index; }

   const int inst_offset() const { return _inst_offset; }

   bool is_same_inst_field(const Type* tp, int id, int index, int offset) {

     return type()->basic_type() == tp->basic_type() &&

            inst_id()     == id     &&

            inst_index()  == index  &&

            inst_offset() == offset &&

            type()->higher_equal(tp);

   }

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual Node *Identity( PhaseTransform *phase );

   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   virtual const RegMask &out_RegMask() const;

   virtual const RegMask &in_RegMask(uint) const;

 #ifndef PRODUCT

   virtual void dump_spec(outputStream *st) const;

 #endif

 #ifdef ASSERT

   void verify_adr_type(VectorSet& visited, const TypePtr* at) const;

   void verify_adr_type(bool recursive = false) const;

 #else //ASSERT

   void verify_adr_type(bool recursive = false) const {}

 #endif //ASSERT

 };

 //------------------------------GotoNode---------------------------------------

 // GotoNodes perform direct branches.

 class GotoNode : public Node {

 public:

   GotoNode( Node *control ) : Node(control) {}

   virtual int Opcode() const;

   virtual bool pinned() const { return true; }

   virtual bool  is_CFG() const { return true; }

   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash

   virtual const Node *is_block_proj() const { return this; }

   virtual bool depends_only_on_test() const { return false; }

   virtual const Type *bottom_type() const { return Type::CONTROL; }

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual Node *Identity( PhaseTransform *phase );

   virtual const RegMask &out_RegMask() const;

 };

 //------------------------------CProjNode--------------------------------------

 // control projection for node that produces multiple control-flow paths

 class CProjNode : public ProjNode {

 public:

   CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {}

   virtual int Opcode() const;

   virtual bool  is_CFG() const { return true; }

   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash

   virtual const Node *is_block_proj() const { return in(0); }

   virtual const RegMask &out_RegMask() const;

   virtual uint ideal_reg() const { return 0; }

 };

 //---------------------------MultiBranchNode-----------------------------------

 // This class defines a MultiBranchNode, a MultiNode which yields multiple

 // control values. These are distinguished from other types of MultiNodes

 // which yield multiple values, but control is always and only projection #0.

 class MultiBranchNode : public MultiNode {

 public:

   MultiBranchNode( uint required ) : MultiNode(required) {

     init_class_id(Class_MultiBranch);

   }

   // returns required number of users to be well formed.

   virtual int required_outcnt() const = 0;

 };

 //------------------------------IfNode-----------------------------------------

 // Output selected Control, based on a boolean test

 class IfNode : public MultiBranchNode {

   // Size is bigger to hold the probability field.  However, _prob does not

   // change the semantics so it does not appear in the hash & cmp functions.

   virtual uint size_of() const { return sizeof(*this); }

 public:

   // Degrees of branch prediction probability by order of magnitude:

   // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance.

   // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N)

 #define PROB_UNLIKELY_MAG(N)    (1e- ## N ## f)

 #define PROB_LIKELY_MAG(N)      (1.0f-PROB_UNLIKELY_MAG(N))

   // Maximum and minimum branch prediction probabilties

   // 1 in 1,000,000 (magnitude 6)

   //

   // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX

   // they are used to distinguish different situations:

   //

   // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to

   // very likely (unlikely) but with a concrete possibility of a rare

   // contrary case.  These constants would be used for pinning

   // measurements, and as measures for assertions that have high

   // confidence, but some evidence of occasional failure.

   //

   // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which

   // there is no evidence at all that the contrary case has ever occurred.

 #define PROB_NEVER              PROB_UNLIKELY_MAG(6)

 #define PROB_ALWAYS             PROB_LIKELY_MAG(6)

 #define PROB_MIN                PROB_UNLIKELY_MAG(6)

 #define PROB_MAX                PROB_LIKELY_MAG(6)

   // Static branch prediction probabilities

   // 1 in 10 (magnitude 1)

 #define PROB_STATIC_INFREQUENT  PROB_UNLIKELY_MAG(1)

 #define PROB_STATIC_FREQUENT    PROB_LIKELY_MAG(1)

   // Fair probability 50/50

 #define PROB_FAIR               (0.5f)

   // Unknown probability sentinel

 #define PROB_UNKNOWN            (-1.0f)

   // Probability "constructors", to distinguish as a probability any manifest

   // constant without a names

 #define PROB_LIKELY(x)          ((float) (x))

 #define PROB_UNLIKELY(x)        (1.0f - (float)(x))

   // Other probabilities in use, but without a unique name, are documented

   // here for lack of a better place:

   //

   // 1 in 1000 probabilities (magnitude 3):

   //     threshold for converting to conditional move

   //     likelihood of null check failure if a null HAS been seen before

   //     likelihood of slow path taken in library calls

   //

   // 1 in 10,000 probabilities (magnitude 4):

   //     threshold for making an uncommon trap probability more extreme

   //     threshold for for making a null check implicit

   //     likelihood of needing a gc if eden top moves during an allocation

   //     likelihood of a predicted call failure

   //

   // 1 in 100,000 probabilities (magnitude 5):

   //     threshold for ignoring counts when estimating path frequency

   //     likelihood of FP clipping failure

   //     likelihood of catching an exception from a try block

   //     likelihood of null check failure if a null has NOT been seen before

   //

   // Magic manifest probabilities such as 0.83, 0.7, ... can be found in

   // gen_subtype_check() and catch_inline_exceptions().

   float _prob;                  // Probability of true path being taken.

   float _fcnt;                  // Frequency counter

   IfNode( Node *control, Node *b, float p, float fcnt )

     : MultiBranchNode(2), _prob(p), _fcnt(fcnt) {

     init_class_id(Class_If);

     init_req(0,control);

     init_req(1,b);

   }

   virtual int Opcode() const;

   virtual bool pinned() const { return true; }

   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }

   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual int required_outcnt() const { return 2; }

   virtual const RegMask &out_RegMask() const;

   void dominated_by(Node* prev_dom, PhaseIterGVN* igvn);

   int is_range_check(Node* &range, Node* &index, jint &offset);

   Node* fold_compares(PhaseGVN* phase);

   static Node* up_one_dom(Node* curr, bool linear_only = false);

   // Takes the type of val and filters it through the test represented

   // by if_proj and returns a more refined type if one is produced.

   // Returns NULL is it couldn't improve the type.

   static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj);

 #ifndef PRODUCT

   virtual void dump_spec(outputStream *st) const;

 #endif

 };

 class IfTrueNode : public CProjNode {

 public:

   IfTrueNode( IfNode *ifnode ) : CProjNode(ifnode,1) {

     init_class_id(Class_IfTrue);

   }

   virtual int Opcode() const;

   virtual Node *Identity( PhaseTransform *phase );

 };

 class IfFalseNode : public CProjNode {

 public:

   IfFalseNode( IfNode *ifnode ) : CProjNode(ifnode,0) {

     init_class_id(Class_IfFalse);

   }

   virtual int Opcode() const;

   virtual Node *Identity( PhaseTransform *phase );

 };

 //------------------------------PCTableNode------------------------------------

 // Build an indirect branch table.  Given a control and a table index,

 // control is passed to the Projection matching the table index.  Used to

 // implement switch statements and exception-handling capabilities.

 // Undefined behavior if passed-in index is not inside the table.

 class PCTableNode : public MultiBranchNode {

   virtual uint hash() const;    // Target count; table size

   virtual uint cmp( const Node &n ) const;

   virtual uint size_of() const { return sizeof(*this); }

 public:

   const uint _size;             // Number of targets

   PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) {

     init_class_id(Class_PCTable);

     init_req(0, ctrl);

     init_req(1, idx);

   }

   virtual int Opcode() const;

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   virtual const Type *bottom_type() const;

   virtual bool pinned() const { return true; }

   virtual int required_outcnt() const { return _size; }

 };

 //------------------------------JumpNode---------------------------------------

 // Indirect branch.  Uses PCTable above to implement a switch statement.

 // It emits as a table load and local branch.

 class JumpNode : public PCTableNode {

 public:

   JumpNode( Node* control, Node* switch_val, uint size) : PCTableNode(control, switch_val, size) {

     init_class_id(Class_Jump);

   }

   virtual int   Opcode() const;

   virtual const RegMask& out_RegMask() const;

   virtual const Node* is_block_proj() const { return this; }

 };

 class JumpProjNode : public JProjNode {

   virtual uint hash() const;

   virtual uint cmp( const Node &n ) const;

   virtual uint size_of() const { return sizeof(*this); }

  private:

   const int  _dest_bci;

   const uint _proj_no;

   const int  _switch_val;

  public:

   JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val)

     : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) {

     init_class_id(Class_JumpProj);

   }

   virtual int Opcode() const;

   virtual const Type* bottom_type() const { return Type::CONTROL; }

   int  dest_bci()    const { return _dest_bci; }

   int  switch_val()  const { return _switch_val; }

   uint proj_no()     const { return _proj_no; }

 #ifndef PRODUCT

   virtual void dump_spec(outputStream *st) const;

 #endif

 };

 //------------------------------CatchNode--------------------------------------

 // Helper node to fork exceptions.  "Catch" catches any exceptions thrown by

 // a just-prior call.  Looks like a PCTableNode but emits no code - just the

 // table.  The table lookup and branch is implemented by RethrowNode.

 class CatchNode : public PCTableNode {

 public:

   CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){

     init_class_id(Class_Catch);

   }

   virtual int Opcode() const;

   virtual const Type *Value( PhaseTransform *phase ) const;

 };

 // CatchProjNode controls which exception handler is targetted after a call.

 // It is passed in the bci of the target handler, or no_handler_bci in case

 // the projection doesn't lead to an exception handler.

 class CatchProjNode : public CProjNode {

   virtual uint hash() const;

   virtual uint cmp( const Node &n ) const;

   virtual uint size_of() const { return sizeof(*this); }

 private:

   const int _handler_bci;

 public:

   enum {

     fall_through_index =  0,      // the fall through projection index

     catch_all_index    =  1,      // the projection index for catch-alls

     no_handler_bci     = -1       // the bci for fall through or catch-all projs

   };

   CatchProjNode(Node* catchnode, uint proj_no, int handler_bci)

     : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) {

     init_class_id(Class_CatchProj);

     assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0");

   }

   virtual int Opcode() const;

   virtual Node *Identity( PhaseTransform *phase );

   virtual const Type *bottom_type() const { return Type::CONTROL; }

   int  handler_bci() const        { return _handler_bci; }

   bool is_handler_proj() const    { return _handler_bci >= 0; }

 #ifndef PRODUCT

   virtual void dump_spec(outputStream *st) const;

 #endif

 };

 //---------------------------------CreateExNode--------------------------------

 // Helper node to create the exception coming back from a call

 class CreateExNode : public TypeNode {

 public:

   CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) {

     init_req(0, control);

     init_req(1, i_o);

   }

   virtual int Opcode() const;

   virtual Node *Identity( PhaseTransform *phase );

   virtual bool pinned() const { return true; }

   uint match_edge(uint idx) const { return 0; }

   virtual uint ideal_reg() const { return Op_RegP; }

 };

 //------------------------------NeverBranchNode-------------------------------

 // The never-taken branch.  Used to give the appearance of exiting infinite

 // loops to those algorithms that like all paths to be reachable.  Encodes

 // empty.

 class NeverBranchNode : public MultiBranchNode {

 public:

   NeverBranchNode( Node *ctrl ) : MultiBranchNode(1) { init_req(0,ctrl); }

   virtual int Opcode() const;

   virtual bool pinned() const { return true; };

   virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; }

   virtual const Type *Value( PhaseTransform *phase ) const;

   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   virtual int required_outcnt() const { return 2; }

   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { }

   virtual uint size(PhaseRegAlloc *ra_) const { return 0; }

 #ifndef PRODUCT

   virtual void format( PhaseRegAlloc *, outputStream *st ) const;

 #endif

 };

 #endif // SHARE_VM_OPTO_CFGNODE_HPP