/*

 * 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

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#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(PhaseGVN* phase) const;

  virtual Node* Identity(PhaseGVN* phase);

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

  virtual const RegMask &out_RegMask() const;

  bool try_clean_mem_phi(PhaseGVN *phase);

  bool optimize_trichotomy(PhaseIterGVN* igvn);

};

//------------------------------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.

  // The following fields are only used for data PhiNodes to indicate

  // that the PhiNode represents the value of a known instance field.

        int _inst_mem_id; // Instance memory id (node index of the memory Phi)

  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 imid = -1,

           const int iid = TypeOopPtr::InstanceTop,

           const int iidx = Compile::AliasIdxTop,

           const int ioffs = Type::OffsetTop )

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

      _adr_type(at),

      _inst_mem_id(imid),

      _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, bool uncast);

  Node* unique_input(PhaseTransform *phase) {

    Node* uin = unique_input(phase, false);

    if (uin == NULL) {

      uin = unique_input(phase, true);

    }

    return uin;

  }

  // 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; }

  void  set_inst_mem_id(int inst_mem_id) { _inst_mem_id = inst_mem_id; }

  const int inst_mem_id() const { return _inst_mem_id; }

  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 mem_id, int id, int index, int offset) {

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

           inst_mem_id() == mem_id &&

           inst_id()     == id     &&

           inst_index()  == index  &&

           inst_offset() == offset &&

           type()->higher_equal(tp);

  }

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

  virtual Node* Identity(PhaseGVN* 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 related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;

  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(PhaseGVN* phase) const;

  virtual Node* Identity(PhaseGVN* phase);

  virtual const RegMask &out_RegMask() const;

#ifndef PRODUCT

  virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;

#endif

};

//------------------------------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); }

private:

  // Helper methods for fold_compares

  bool cmpi_folds(PhaseIterGVN* igvn);

  bool is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn);

  bool has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail);

  bool has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn);

  Node* merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);

  static void improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn);

  bool is_cmp_with_loadrange(ProjNode* proj);

  bool is_null_check(ProjNode* proj, PhaseIterGVN* igvn);

  bool is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn);

  void reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn);

  ProjNode* uncommon_trap_proj(CallStaticJavaNode*& call) const;

  bool fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn);

  static bool is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc);

protected:

  ProjNode* range_check_trap_proj(int& flip, Node*& l, Node*& r);

  Node* Ideal_common(PhaseGVN *phase, bool can_reshape);

  Node* search_identical(int dist);

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(PhaseGVN* phase) const;

  virtual int required_outcnt() const { return 2; }

  virtual const RegMask &out_RegMask() const;

  Node* fold_compares(PhaseIterGVN* phase);

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

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

  // 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;

  virtual void related(GrowableArray <Node *> *in_rel, GrowableArray <Node *> *out_rel, bool compact) const;

#endif

};

class RangeCheckNode : public IfNode {

private:

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

public:

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

    : IfNode(control, b, p, fcnt) {

    init_class_id(Class_RangeCheck);

  }

  virtual int Opcode() const;

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

};

class IfProjNode : public CProjNode {

public:

  IfProjNode(IfNode *ifnode, uint idx) : CProjNode(ifnode,idx) {}

  virtual Node* Identity(PhaseGVN* phase);

protected:

  // Type of If input when this branch is always taken

  virtual bool always_taken(const TypeTuple* t) const = 0;

#ifndef PRODUCT

public:

  virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;

#endif

};

class IfTrueNode : public IfProjNode {

public:

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

    init_class_id(Class_IfTrue);

  }

  virtual int Opcode() const;

protected:

  virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFTRUE; }

};

class IfFalseNode : public IfProjNode {

public:

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

    init_class_id(Class_IfFalse);

  }

  virtual int Opcode() const;

protected:

  virtual bool always_taken(const TypeTuple* t) const { return t == TypeTuple::IFFALSE; }

};

//------------------------------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(PhaseGVN* 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 {

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

public:

  float* _probs; // probability of each projection

  float _fcnt;   // total number of times this Jump was executed

  JumpNode( Node* control, Node* switch_val, uint size, float* probs, float cnt)

    : PCTableNode(control, switch_val, size),

      _probs(probs), _fcnt(cnt) {

    init_class_id(Class_Jump);

  }

  virtual int   Opcode() const;

  virtual const RegMask& out_RegMask() const;

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

#ifndef PRODUCT

  virtual void related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;

#endif

};

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;