--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/opto/phaseX.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,516 @@
+/*
+ * 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.
+ *
+ */
+
+class Compile;
+class ConINode;
+class ConLNode;
+class Node;
+class Type;
+class PhaseTransform;
+class   PhaseGVN;
+class     PhaseIterGVN;
+class       PhaseCCP;
+class   PhasePeephole;
+class   PhaseRegAlloc;
+
+
+//-----------------------------------------------------------------------------
+// Expandable closed hash-table of nodes, initialized to NULL.
+// Note that the constructor just zeros things
+// Storage is reclaimed when the Arena's lifetime is over.
+class NodeHash : public StackObj {
+protected:
+  Arena *_a;                    // Arena to allocate in
+  uint   _max;                  // Size of table (power of 2)
+  uint   _inserts;              // For grow and debug, count of hash_inserts
+  uint   _insert_limit;         // 'grow' when _inserts reaches _insert_limit
+  Node **_table;                // Hash table of Node pointers
+  Node  *_sentinel;             // Replaces deleted entries in hash table
+
+public:
+  NodeHash(uint est_max_size);
+  NodeHash(Arena *arena, uint est_max_size);
+  NodeHash(NodeHash *use_this_state);
+#ifdef ASSERT
+  ~NodeHash();                  // Unlock all nodes upon destruction of table.
+  void operator=(const NodeHash&); // Unlock all nodes upon replacement of table.
+#endif
+  Node  *hash_find(const Node*);// Find an equivalent version in hash table
+  Node  *hash_find_insert(Node*);// If not in table insert else return found node
+  void   hash_insert(Node*);    // Insert into hash table
+  bool   hash_delete(const Node*);// Replace with _sentinel in hash table
+  void   check_grow() {
+    _inserts++;
+    if( _inserts == _insert_limit ) { grow(); }
+    assert( _inserts <= _insert_limit, "hash table overflow");
+    assert( _inserts < _max, "hash table overflow" );
+  }
+  static uint round_up(uint);   // Round up to nearest power of 2
+  void   grow();                // Grow _table to next power of 2 and rehash
+  // Return 75% of _max, rounded up.
+  uint   insert_limit() const { return _max - (_max>>2); }
+
+  void   clear();               // Set all entries to NULL, keep storage.
+  // Size of hash table
+  uint   size()         const { return _max; }
+  // Return Node* at index in table
+  Node  *at(uint table_index) {
+    assert(table_index < _max, "Must be within table");
+    return _table[table_index];
+  }
+
+  void   remove_useless_nodes(VectorSet &useful); // replace with sentinel
+
+  Node  *sentinel() { return _sentinel; }
+
+#ifndef PRODUCT
+  Node  *find_index(uint idx);  // For debugging
+  void   dump();                // For debugging, dump statistics
+#endif
+  uint   _grows;                // For debugging, count of table grow()s
+  uint   _look_probes;          // For debugging, count of hash probes
+  uint   _lookup_hits;          // For debugging, count of hash_finds
+  uint   _lookup_misses;        // For debugging, count of hash_finds
+  uint   _insert_probes;        // For debugging, count of hash probes
+  uint   _delete_probes;        // For debugging, count of hash probes for deletes
+  uint   _delete_hits;          // For debugging, count of hash probes for deletes
+  uint   _delete_misses;        // For debugging, count of hash probes for deletes
+  uint   _total_inserts;        // For debugging, total inserts into hash table
+  uint   _total_insert_probes;  // For debugging, total probes while inserting
+};
+
+
+//-----------------------------------------------------------------------------
+// Map dense integer indices to Types.  Uses classic doubling-array trick.
+// Abstractly provides an infinite array of Type*'s, initialized to NULL.
+// Note that the constructor just zeros things, and since I use Arena
+// allocation I do not need a destructor to reclaim storage.
+// Despite the general name, this class is customized for use by PhaseTransform.
+class Type_Array : public StackObj {
+  Arena *_a;                    // Arena to allocate in
+  uint   _max;
+  const Type **_types;
+  void grow( uint i );          // Grow array node to fit
+  const Type *operator[] ( uint i ) const // Lookup, or NULL for not mapped
+  { return (i<_max) ? _types[i] : (Type*)NULL; }
+  friend class PhaseTransform;
+public:
+  Type_Array(Arena *a) : _a(a), _max(0), _types(0) {}
+  Type_Array(Type_Array *ta) : _a(ta->_a), _max(ta->_max), _types(ta->_types) { }
+  const Type *fast_lookup(uint i) const{assert(i<_max,"oob");return _types[i];}
+  // Extend the mapping: index i maps to Type *n.
+  void map( uint i, const Type *n ) { if( i>=_max ) grow(i); _types[i] = n; }
+  uint Size() const { return _max; }
+#ifndef PRODUCT
+  void dump() const;
+#endif
+};
+
+
+//------------------------------PhaseRemoveUseless-----------------------------
+// Remove useless nodes from GVN hash-table, worklist, and graph
+class PhaseRemoveUseless : public Phase {
+protected:
+  Unique_Node_List _useful;   // Nodes reachable from root
+                              // list is allocated from current resource area
+public:
+  PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist );
+
+  Unique_Node_List *get_useful() { return &_useful; }
+};
+
+
+//------------------------------PhaseTransform---------------------------------
+// Phases that analyze, then transform.  Constructing the Phase object does any
+// global or slow analysis.  The results are cached later for a fast
+// transformation pass.  When the Phase object is deleted the cached analysis
+// results are deleted.
+class PhaseTransform : public Phase {
+protected:
+  Arena*     _arena;
+  Node_Array _nodes;           // Map old node indices to new nodes.
+  Type_Array _types;           // Map old node indices to Types.
+
+  // ConNode caches:
+  enum { _icon_min = -1 * HeapWordSize,
+         _icon_max = 16 * HeapWordSize,
+         _lcon_min = _icon_min,
+         _lcon_max = _icon_max,
+         _zcon_max = (uint)T_CONFLICT
+  };
+  ConINode* _icons[_icon_max - _icon_min + 1];   // cached jint constant nodes
+  ConLNode* _lcons[_lcon_max - _lcon_min + 1];   // cached jlong constant nodes
+  ConNode*  _zcons[_zcon_max + 1];               // cached is_zero_type nodes
+  void init_con_caches();
+
+  // Support both int and long caches because either might be an intptr_t,
+  // so they show up frequently in address computations.
+
+public:
+  PhaseTransform( PhaseNumber pnum );
+  PhaseTransform( Arena *arena, PhaseNumber pnum );
+  PhaseTransform( PhaseTransform *phase, PhaseNumber pnum );
+
+  Arena*      arena()   { return _arena; }
+  Type_Array& types()   { return _types; }
+  // _nodes is used in varying ways by subclasses, which define local accessors
+
+public:
+  // Get a previously recorded type for the node n.
+  // This type must already have been recorded.
+  // If you want the type of a very new (untransformed) node,
+  // you must use type_or_null, and test the result for NULL.
+  const Type* type(const Node* n) const {
+    const Type* t = _types.fast_lookup(n->_idx);
+    assert(t != NULL, "must set before get");
+    return t;
+  }
+  // Get a previously recorded type for the node n,
+  // or else return NULL if there is none.
+  const Type* type_or_null(const Node* n) const {
+    return _types.fast_lookup(n->_idx);
+  }
+  // Record a type for a node.
+  void    set_type(const Node* n, const Type *t) {
+    assert(t != NULL, "type must not be null");
+    _types.map(n->_idx, t);
+  }
+  // Record an initial type for a node, the node's bottom type.
+  void    set_type_bottom(const Node* n) {
+    // Use this for initialization when bottom_type() (or better) is not handy.
+    // Usually the initialization shoudl be to n->Value(this) instead,
+    // or a hand-optimized value like Type::MEMORY or Type::CONTROL.
+    assert(_types[n->_idx] == NULL, "must set the initial type just once");
+    _types.map(n->_idx, n->bottom_type());
+  }
+  // Make sure the types array is big enough to record a size for the node n.
+  // (In product builds, we never want to do range checks on the types array!)
+  void ensure_type_or_null(const Node* n) {
+    if (n->_idx >= _types.Size())
+      _types.map(n->_idx, NULL);   // Grow the types array as needed.
+  }
+
+  // Utility functions:
+  const TypeInt*  find_int_type( Node* n);
+  const TypeLong* find_long_type(Node* n);
+  jint  find_int_con( Node* n, jint  value_if_unknown) {
+    const TypeInt* t = find_int_type(n);
+    return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
+  }
+  jlong find_long_con(Node* n, jlong value_if_unknown) {
+    const TypeLong* t = find_long_type(n);
+    return (t != NULL && t->is_con()) ? t->get_con() : value_if_unknown;
+  }
+
+  // Make an idealized constant, i.e., one of ConINode, ConPNode, ConFNode, etc.
+  // Same as transform(ConNode::make(t)).
+  ConNode* makecon(const Type* t);
+  virtual ConNode* uncached_makecon(const Type* t)  // override in PhaseValues
+  { ShouldNotCallThis(); return NULL; }
+
+  // Fast int or long constant.  Same as TypeInt::make(i) or TypeLong::make(l).
+  ConINode* intcon(jint i);
+  ConLNode* longcon(jlong l);
+
+  // Fast zero or null constant.  Same as makecon(Type::get_zero_type(bt)).
+  ConNode* zerocon(BasicType bt);
+
+  // Return a node which computes the same function as this node, but
+  // in a faster or cheaper fashion.
+  virtual Node *transform( Node *n ) = 0;
+
+  // Return whether two Nodes are equivalent.
+  // Must not be recursive, since the recursive version is built from this.
+  // For pessimistic optimizations this is simply pointer equivalence.
+  bool eqv(const Node* n1, const Node* n2) const { return n1 == n2; }
+
+  // Return whether two Nodes are equivalent, after stripping casting.
+  bool eqv_uncast(const Node* n1, const Node* n2) const {
+    return eqv(n1->uncast(), n2->uncast());
+  }
+
+  // For pessimistic passes, the return type must monotonically narrow.
+  // For optimistic  passes, the return type must monotonically widen.
+  // It is possible to get into a "death march" in either type of pass,
+  // where the types are continually moving but it will take 2**31 or
+  // more steps to converge.  This doesn't happen on most normal loops.
+  //
+  // Here is an example of a deadly loop for an optimistic pass, along
+  // with a partial trace of inferred types:
+  //    x = phi(0,x'); L: x' = x+1; if (x' >= 0) goto L;
+  //    0                 1                join([0..max], 1)
+  //    [0..1]            [1..2]           join([0..max], [1..2])
+  //    [0..2]            [1..3]           join([0..max], [1..3])
+  //      ... ... ...
+  //    [0..max]          [min]u[1..max]   join([0..max], [min..max])
+  //    [0..max] ==> fixpoint
+  // We would have proven, the hard way, that the iteration space is all
+  // non-negative ints, with the loop terminating due to 32-bit overflow.
+  //
+  // Here is the corresponding example for a pessimistic pass:
+  //    x = phi(0,x'); L: x' = x-1; if (x' >= 0) goto L;
+  //    int               int              join([0..max], int)
+  //    [0..max]          [-1..max-1]      join([0..max], [-1..max-1])
+  //    [0..max-1]        [-1..max-2]      join([0..max], [-1..max-2])
+  //      ... ... ...
+  //    [0..1]            [-1..0]          join([0..max], [-1..0])
+  //    0                 -1               join([0..max], -1)
+  //    0 == fixpoint
+  // We would have proven, the hard way, that the iteration space is {0}.
+  // (Usually, other optimizations will make the "if (x >= 0)" fold up
+  // before we get into trouble.  But not always.)
+  //
+  // It's a pleasant thing to observe that the pessimistic pass
+  // will make short work of the optimistic pass's deadly loop,
+  // and vice versa.  That is a good example of the complementary
+  // purposes of the CCP (optimistic) vs. GVN (pessimistic) phases.
+  //
+  // In any case, only widen or narrow a few times before going to the
+  // correct flavor of top or bottom.
+  //
+  // This call only needs to be made once as the data flows around any
+  // given cycle.  We do it at Phis, and nowhere else.
+  // The types presented are the new type of a phi (computed by PhiNode::Value)
+  // and the previously computed type, last time the phi was visited.
+  //
+  // The third argument is upper limit for the saturated value,
+  // if the phase wishes to widen the new_type.
+  // If the phase is narrowing, the old type provides a lower limit.
+  // Caller guarantees that old_type and new_type are no higher than limit_type.
+  virtual const Type* saturate(const Type* new_type, const Type* old_type,
+                               const Type* limit_type) const
+  { ShouldNotCallThis(); return NULL; }
+
+#ifndef PRODUCT
+  void dump_old2new_map() const;
+  void dump_new( uint new_lidx ) const;
+  void dump_types() const;
+  void dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl = true);
+  void dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited);
+
+  uint   _count_progress;       // For profiling, count transforms that make progress
+  void   set_progress()        { ++_count_progress; assert( allow_progress(),"No progress allowed during verification") }
+  void   clear_progress()      { _count_progress = 0; }
+  uint   made_progress() const { return _count_progress; }
+
+  uint   _count_transforms;     // For profiling, count transforms performed
+  void   set_transforms()      { ++_count_transforms; }
+  void   clear_transforms()    { _count_transforms = 0; }
+  uint   made_transforms() const{ return _count_transforms; }
+
+  bool   _allow_progress;      // progress not allowed during verification pass
+  void   set_allow_progress(bool allow) { _allow_progress = allow; }
+  bool   allow_progress()               { return _allow_progress; }
+#endif
+};
+
+//------------------------------PhaseValues------------------------------------
+// Phase infrastructure to support values
+class PhaseValues : public PhaseTransform {
+protected:
+  NodeHash  _table;             // Hash table for value-numbering
+
+public:
+  PhaseValues( Arena *arena, uint est_max_size );
+  PhaseValues( PhaseValues *pt );
+  PhaseValues( PhaseValues *ptv, const char *dummy );
+  NOT_PRODUCT( ~PhaseValues(); )
+  virtual PhaseIterGVN *is_IterGVN() { return 0; }
+
+  // Some Ideal and other transforms delete --> modify --> insert values
+  bool   hash_delete(Node *n)     { return _table.hash_delete(n); }
+  void   hash_insert(Node *n)     { _table.hash_insert(n); }
+  Node  *hash_find_insert(Node *n){ return _table.hash_find_insert(n); }
+  Node  *hash_find(const Node *n) { return _table.hash_find(n); }
+
+  // Used after parsing to eliminate values that are no longer in program
+  void   remove_useless_nodes(VectorSet &useful) { _table.remove_useless_nodes(useful); }
+
+  virtual ConNode* uncached_makecon(const Type* t);  // override from PhaseTransform
+
+  virtual const Type* saturate(const Type* new_type, const Type* old_type,
+                               const Type* limit_type) const
+  { return new_type; }
+
+#ifndef PRODUCT
+  uint   _count_new_values;     // For profiling, count new values produced
+  void    inc_new_values()        { ++_count_new_values; }
+  void    clear_new_values()      { _count_new_values = 0; }
+  uint    made_new_values() const { return _count_new_values; }
+#endif
+};
+
+
+//------------------------------PhaseGVN---------------------------------------
+// Phase for performing local, pessimistic GVN-style optimizations.
+class PhaseGVN : public PhaseValues {
+public:
+  PhaseGVN( Arena *arena, uint est_max_size ) : PhaseValues( arena, est_max_size ) {}
+  PhaseGVN( PhaseGVN *gvn ) : PhaseValues( gvn ) {}
+  PhaseGVN( PhaseGVN *gvn, const char *dummy ) : PhaseValues( gvn, dummy ) {}
+
+  // Return a node which computes the same function as this node, but
+  // in a faster or cheaper fashion.
+  Node  *transform( Node *n );
+  Node  *transform_no_reclaim( Node *n );
+
+  // Check for a simple dead loop when a data node references itself.
+  DEBUG_ONLY(void dead_loop_check(Node *n);)
+};
+
+//------------------------------PhaseIterGVN-----------------------------------
+// Phase for iteratively performing local, pessimistic GVN-style optimizations.
+// and ideal transformations on the graph.
+class PhaseIterGVN : public PhaseGVN {
+  // Idealize old Node 'n' with respect to its inputs and its value
+  virtual Node *transform_old( Node *a_node );
+protected:
+
+  // Idealize new Node 'n' with respect to its inputs and its value
+  virtual Node *transform( Node *a_node );
+
+  // Warm up hash table, type table and initial worklist
+  void init_worklist( Node *a_root );
+
+  virtual const Type* saturate(const Type* new_type, const Type* old_type,
+                               const Type* limit_type) const;
+  // Usually returns new_type.  Returns old_type if new_type is only a slight
+  // improvement, such that it would take many (>>10) steps to reach 2**32.
+
+public:
+  PhaseIterGVN( PhaseIterGVN *igvn ); // Used by CCP constructor
+  PhaseIterGVN( PhaseGVN *gvn ); // Used after Parser
+  PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ); // Used after +VerifyOpto
+
+  virtual PhaseIterGVN *is_IterGVN() { return this; }
+
+  Unique_Node_List _worklist;       // Iterative worklist
+
+  // Given def-use info and an initial worklist, apply Node::Ideal,
+  // Node::Value, Node::Identity, hash-based value numbering, Node::Ideal_DU
+  // and dominator info to a fixed point.
+  void optimize();
+
+  // Register a new node with the iter GVN pass without transforming it.
+  // Used when we need to restructure a Region/Phi area and all the Regions
+  // and Phis need to complete this one big transform before any other
+  // transforms can be triggered on the region.
+  // Optional 'orig' is an earlier version of this node.
+  // It is significant only for debugging and profiling.
+  Node* register_new_node_with_optimizer(Node* n, Node* orig = NULL);
+
+  // Kill a globally dead Node.   It is allowed to have uses which are
+  // assumed dead and left 'in limbo'.
+  void remove_globally_dead_node( Node *dead );
+
+  // Kill all inputs to a dead node, recursively making more dead nodes.
+  // The Node must be dead locally, i.e., have no uses.
+  void remove_dead_node( Node *dead ) {
+    assert(dead->outcnt() == 0 && !dead->is_top(), "node must be dead");
+    remove_globally_dead_node(dead);
+  }
+
+  // Subsume users of node 'old' into node 'nn'
+  // If no Def-Use info existed for 'nn' it will after call.
+  void subsume_node( Node *old, Node *nn );
+
+  // Add users of 'n' to worklist
+  void add_users_to_worklist0( Node *n );
+  void add_users_to_worklist ( Node *n );
+
+#ifndef PRODUCT
+protected:
+  // Sub-quadratic implementation of VerifyIterativeGVN.
+  unsigned long _verify_counter;
+  unsigned long _verify_full_passes;
+  enum { _verify_window_size = 30 };
+  Node* _verify_window[_verify_window_size];
+  void verify_step(Node* n);
+#endif
+};
+
+//------------------------------PhaseCCP---------------------------------------
+// Phase for performing global Conditional Constant Propagation.
+// Should be replaced with combined CCP & GVN someday.
+class PhaseCCP : public PhaseIterGVN {
+  // Non-recursive.  Use analysis to transform single Node.
+  virtual Node *transform_once( Node *n );
+
+public:
+  PhaseCCP( PhaseIterGVN *igvn ); // Compute conditional constants
+  NOT_PRODUCT( ~PhaseCCP(); )
+
+  // Worklist algorithm identifies constants
+  void analyze();
+  // Recursive traversal of program.  Used analysis to modify program.
+  virtual Node *transform( Node *n );
+  // Do any transformation after analysis
+  void          do_transform();
+
+  virtual const Type* saturate(const Type* new_type, const Type* old_type,
+                               const Type* limit_type) const;
+  // Returns new_type->widen(old_type), which increments the widen bits until
+  // giving up with TypeInt::INT or TypeLong::LONG.
+  // Result is clipped to limit_type if necessary.
+
+#ifndef PRODUCT
+  static uint _total_invokes;    // For profiling, count invocations
+  void    inc_invokes()          { ++PhaseCCP::_total_invokes; }
+
+  static uint _total_constants;  // For profiling, count constants found
+  uint   _count_constants;
+  void    clear_constants()      { _count_constants = 0; }
+  void    inc_constants()        { ++_count_constants; }
+  uint    count_constants() const { return _count_constants; }
+
+  static void print_statistics();
+#endif
+};
+
+
+//------------------------------PhasePeephole----------------------------------
+// Phase for performing peephole optimizations on register allocated basic blocks.
+class PhasePeephole : public PhaseTransform {
+  PhaseRegAlloc *_regalloc;
+  PhaseCFG     &_cfg;
+  // Recursive traversal of program.  Pure function is unused in this phase
+  virtual Node *transform( Node *n );
+
+public:
+  PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg );
+  NOT_PRODUCT( ~PhasePeephole(); )
+
+  // Do any transformation after analysis
+  void          do_transform();
+
+#ifndef PRODUCT
+  static uint _total_peepholes;  // For profiling, count peephole rules applied
+  uint   _count_peepholes;
+  void    clear_peepholes()      { _count_peepholes = 0; }
+  void    inc_peepholes()        { ++_count_peepholes; }
+  uint    count_peepholes() const { return _count_peepholes; }
+
+  static void print_statistics();
+#endif
+};