/* * 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 };