--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/opto/cfgnode.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,481 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// 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;
+};
+
+//------------------------------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.
+  // 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 a unique non-trivial input, if any.
+  // Ignore casts if it helps.  Return NULL on failure.
+  Node* unique_input(PhaseTransform *phase);
+  // 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 )
+    : TypeNode(t,r->req()), _adr_type(at) {
+    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;
+  // 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!
+  }
+
+  // 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() 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; }
+  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) {
+    init_flags(Flag_is_Goto);
+  }
+  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);
+  }
+};
+
+//------------------------------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 const RegMask &out_RegMask() const;
+  void dominated_by(Node* prev_dom, PhaseIterGVN* igvn);
+  int is_range_check(Node* &range, Node* &index, jint &offset);
+  static Node* up_one_dom(Node* curr, bool linear_only = false);
+
+#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; }
+};
+
+//------------------------------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 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
+};