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

 /*

  * Copyright 1997-2009 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);

     // this may invalidate cached cons so reset the cache

     init_con_caches();

   }

   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 {

  private:

   bool _delay_transform;  // When true simply register the node when calling transform

                           // instead of actually optimizing it

   // 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 );

   // Replace old node with new one.

   void replace_node( Node *old, Node *nn ) {

     add_users_to_worklist(old);

     hash_delete(old);

     subsume_node(old, nn);

   }

   bool delay_transform() const { return _delay_transform; }

   void set_delay_transform(bool delay) {

     _delay_transform = delay;

   }

 #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

 };