/* * Copyright (c) 1997, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "memory/allocation.inline.hpp" #include "opto/block.hpp" #include "opto/callnode.hpp" #include "opto/cfgnode.hpp" #include "opto/connode.hpp" #include "opto/idealGraphPrinter.hpp" #include "opto/loopnode.hpp" #include "opto/machnode.hpp" #include "opto/opcodes.hpp" #include "opto/phaseX.hpp" #include "opto/regalloc.hpp" #include "opto/rootnode.hpp" //============================================================================= #define NODE_HASH_MINIMUM_SIZE 255 //------------------------------NodeHash--------------------------------------- NodeHash::NodeHash(uint est_max_size) : _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), _a(Thread::current()->resource_area()), _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ), _inserts(0), _insert_limit( insert_limit() ), _look_probes(0), _lookup_hits(0), _lookup_misses(0), _total_insert_probes(0), _total_inserts(0), _insert_probes(0), _grows(0) { // _sentinel must be in the current node space _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control); memset(_table,0,sizeof(Node*)*_max); } //------------------------------NodeHash--------------------------------------- NodeHash::NodeHash(Arena *arena, uint est_max_size) : _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), _a(arena), _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), _inserts(0), _insert_limit( insert_limit() ), _look_probes(0), _lookup_hits(0), _lookup_misses(0), _delete_probes(0), _delete_hits(0), _delete_misses(0), _total_insert_probes(0), _total_inserts(0), _insert_probes(0), _grows(0) { // _sentinel must be in the current node space _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control); memset(_table,0,sizeof(Node*)*_max); } //------------------------------NodeHash--------------------------------------- NodeHash::NodeHash(NodeHash *nh) { debug_only(_table = (Node**)badAddress); // interact correctly w/ operator= // just copy in all the fields *this = *nh; // nh->_sentinel must be in the current node space } void NodeHash::replace_with(NodeHash *nh) { debug_only(_table = (Node**)badAddress); // interact correctly w/ operator= // just copy in all the fields *this = *nh; // nh->_sentinel must be in the current node space } //------------------------------hash_find-------------------------------------- // Find in hash table Node *NodeHash::hash_find( const Node *n ) { // ((Node*)n)->set_hash( n->hash() ); uint hash = n->hash(); if (hash == Node::NO_HASH) { debug_only( _lookup_misses++ ); return NULL; } uint key = hash & (_max-1); uint stride = key | 0x01; debug_only( _look_probes++ ); Node *k = _table[key]; // Get hashed value if( !k ) { // ?Miss? debug_only( _lookup_misses++ ); return NULL; // Miss! } int op = n->Opcode(); uint req = n->req(); while( 1 ) { // While probing hash table if( k->req() == req && // Same count of inputs k->Opcode() == op ) { // Same Opcode for( uint i=0; iin(i)!=k->in(i)) // Different inputs? goto collision; // "goto" is a speed hack... if( n->cmp(*k) ) { // Check for any special bits debug_only( _lookup_hits++ ); return k; // Hit! } } collision: debug_only( _look_probes++ ); key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime k = _table[key]; // Get hashed value if( !k ) { // ?Miss? debug_only( _lookup_misses++ ); return NULL; // Miss! } } ShouldNotReachHere(); return NULL; } //------------------------------hash_find_insert------------------------------- // Find in hash table, insert if not already present // Used to preserve unique entries in hash table Node *NodeHash::hash_find_insert( Node *n ) { // n->set_hash( ); uint hash = n->hash(); if (hash == Node::NO_HASH) { debug_only( _lookup_misses++ ); return NULL; } uint key = hash & (_max-1); uint stride = key | 0x01; // stride must be relatively prime to table siz uint first_sentinel = 0; // replace a sentinel if seen. debug_only( _look_probes++ ); Node *k = _table[key]; // Get hashed value if( !k ) { // ?Miss? debug_only( _lookup_misses++ ); _table[key] = n; // Insert into table! debug_only(n->enter_hash_lock()); // Lock down the node while in the table. check_grow(); // Grow table if insert hit limit return NULL; // Miss! } else if( k == _sentinel ) { first_sentinel = key; // Can insert here } int op = n->Opcode(); uint req = n->req(); while( 1 ) { // While probing hash table if( k->req() == req && // Same count of inputs k->Opcode() == op ) { // Same Opcode for( uint i=0; iin(i)!=k->in(i)) // Different inputs? goto collision; // "goto" is a speed hack... if( n->cmp(*k) ) { // Check for any special bits debug_only( _lookup_hits++ ); return k; // Hit! } } collision: debug_only( _look_probes++ ); key = (key + stride) & (_max-1); // Stride through table w/ relative prime k = _table[key]; // Get hashed value if( !k ) { // ?Miss? debug_only( _lookup_misses++ ); key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel? _table[key] = n; // Insert into table! debug_only(n->enter_hash_lock()); // Lock down the node while in the table. check_grow(); // Grow table if insert hit limit return NULL; // Miss! } else if( first_sentinel == 0 && k == _sentinel ) { first_sentinel = key; // Can insert here } } ShouldNotReachHere(); return NULL; } //------------------------------hash_insert------------------------------------ // Insert into hash table void NodeHash::hash_insert( Node *n ) { // // "conflict" comments -- print nodes that conflict // bool conflict = false; // n->set_hash(); uint hash = n->hash(); if (hash == Node::NO_HASH) { return; } check_grow(); uint key = hash & (_max-1); uint stride = key | 0x01; while( 1 ) { // While probing hash table debug_only( _insert_probes++ ); Node *k = _table[key]; // Get hashed value if( !k || (k == _sentinel) ) break; // Found a slot assert( k != n, "already inserted" ); // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; } key = (key + stride) & (_max-1); // Stride through table w/ relative prime } _table[key] = n; // Insert into table! debug_only(n->enter_hash_lock()); // Lock down the node while in the table. // if( conflict ) { n->dump(); } } //------------------------------hash_delete------------------------------------ // Replace in hash table with sentinel bool NodeHash::hash_delete( const Node *n ) { Node *k; uint hash = n->hash(); if (hash == Node::NO_HASH) { debug_only( _delete_misses++ ); return false; } uint key = hash & (_max-1); uint stride = key | 0x01; debug_only( uint counter = 0; ); for( ; /* (k != NULL) && (k != _sentinel) */; ) { debug_only( counter++ ); debug_only( _delete_probes++ ); k = _table[key]; // Get hashed value if( !k ) { // Miss? debug_only( _delete_misses++ ); #ifdef ASSERT if( VerifyOpto ) { for( uint i=0; i < _max; i++ ) assert( _table[i] != n, "changed edges with rehashing" ); } #endif return false; // Miss! Not in chain } else if( n == k ) { debug_only( _delete_hits++ ); _table[key] = _sentinel; // Hit! Label as deleted entry debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table. return true; } else { // collision: move through table with prime offset key = (key + stride/*7*/) & (_max-1); assert( counter <= _insert_limit, "Cycle in hash-table"); } } ShouldNotReachHere(); return false; } //------------------------------round_up--------------------------------------- // Round up to nearest power of 2 uint NodeHash::round_up( uint x ) { x += (x>>2); // Add 25% slop if( x <16 ) return 16; // Small stuff uint i=16; while( i < x ) i <<= 1; // Double to fit return i; // Return hash table size } //------------------------------grow------------------------------------------- // Grow _table to next power of 2 and insert old entries void NodeHash::grow() { // Record old state uint old_max = _max; Node **old_table = _table; // Construct new table with twice the space _grows++; _total_inserts += _inserts; _total_insert_probes += _insert_probes; _inserts = 0; _insert_probes = 0; _max = _max << 1; _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) ); memset(_table,0,sizeof(Node*)*_max); _insert_limit = insert_limit(); // Insert old entries into the new table for( uint i = 0; i < old_max; i++ ) { Node *m = *old_table++; if( !m || m == _sentinel ) continue; debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table. hash_insert(m); } } //------------------------------clear------------------------------------------ // Clear all entries in _table to NULL but keep storage void NodeHash::clear() { #ifdef ASSERT // Unlock all nodes upon removal from table. for (uint i = 0; i < _max; i++) { Node* n = _table[i]; if (!n || n == _sentinel) continue; n->exit_hash_lock(); } #endif memset( _table, 0, _max * sizeof(Node*) ); } //-----------------------remove_useless_nodes---------------------------------- // Remove useless nodes from value table, // implementation does not depend on hash function void NodeHash::remove_useless_nodes(VectorSet &useful) { // Dead nodes in the hash table inherited from GVN should not replace // existing nodes, remove dead nodes. uint max = size(); Node *sentinel_node = sentinel(); for( uint i = 0; i < max; ++i ) { Node *n = at(i); if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) { debug_only(n->exit_hash_lock()); // Unlock the node when removed _table[i] = sentinel_node; // Replace with placeholder } } } void NodeHash::check_no_speculative_types() { #ifdef ASSERT uint max = size(); Node *sentinel_node = sentinel(); for (uint i = 0; i < max; ++i) { Node *n = at(i); if(n != NULL && n != sentinel_node && n->is_Type()) { TypeNode* tn = n->as_Type(); const Type* t = tn->type(); const Type* t_no_spec = t->remove_speculative(); assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup"); } } #endif } #ifndef PRODUCT //------------------------------dump------------------------------------------- // Dump statistics for the hash table void NodeHash::dump() { _total_inserts += _inserts; _total_insert_probes += _insert_probes; if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) { if (WizardMode) { for (uint i=0; i<_max; i++) { if (_table[i]) tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx); } } tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max); tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0); tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses)); tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts); // sentinels increase lookup cost, but not insert cost assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function"); assert( _inserts+(_inserts>>3) < _max, "table too full" ); assert( _inserts*3+100 >= _insert_probes, "bad hash function" ); } } Node *NodeHash::find_index(uint idx) { // For debugging // Find an entry by its index value for( uint i = 0; i < _max; i++ ) { Node *m = _table[i]; if( !m || m == _sentinel ) continue; if( m->_idx == (uint)idx ) return m; } return NULL; } #endif #ifdef ASSERT NodeHash::~NodeHash() { // Unlock all nodes upon destruction of table. if (_table != (Node**)badAddress) clear(); } void NodeHash::operator=(const NodeHash& nh) { // Unlock all nodes upon replacement of table. if (&nh == this) return; if (_table != (Node**)badAddress) clear(); memcpy(this, &nh, sizeof(*this)); // Do not increment hash_lock counts again. // Instead, be sure we never again use the source table. ((NodeHash*)&nh)->_table = (Node**)badAddress; } #endif //============================================================================= //------------------------------PhaseRemoveUseless----------------------------- // 1) Use a breadthfirst walk to collect useful nodes reachable from root. PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN *gvn, Unique_Node_List *worklist, PhaseNumber phase_num) : Phase(phase_num), _useful(Thread::current()->resource_area()) { // Implementation requires 'UseLoopSafepoints == true' and an edge from root // to each SafePointNode at a backward branch. Inserted in add_safepoint(). if( !UseLoopSafepoints || !OptoRemoveUseless ) return; // Identify nodes that are reachable from below, useful. C->identify_useful_nodes(_useful); // Update dead node list C->update_dead_node_list(_useful); // Remove all useless nodes from PhaseValues' recorded types // Must be done before disconnecting nodes to preserve hash-table-invariant gvn->remove_useless_nodes(_useful.member_set()); // Remove all useless nodes from future worklist worklist->remove_useless_nodes(_useful.member_set()); // Disconnect 'useless' nodes that are adjacent to useful nodes C->remove_useless_nodes(_useful); // Remove edges from "root" to each SafePoint at a backward branch. // They were inserted during parsing (see add_safepoint()) to make infinite // loops without calls or exceptions visible to root, i.e., useful. Node *root = C->root(); if( root != NULL ) { for( uint i = root->req(); i < root->len(); ++i ) { Node *n = root->in(i); if( n != NULL && n->is_SafePoint() ) { root->rm_prec(i); --i; } } } } //============================================================================= //------------------------------PhaseRenumberLive------------------------------ // First, remove useless nodes (equivalent to identifying live nodes). // Then, renumber live nodes. // // The set of live nodes is returned by PhaseRemoveUseless in the _useful structure. // If the number of live nodes is 'x' (where 'x' == _useful.size()), then the // PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique // value in the range [0, x). // // At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is // updated to 'x' and the list of dead nodes is reset (as there are no dead nodes). // // The PhaseRenumberLive phase updates two data structures with the new node IDs. // (1) The worklist is used by the PhaseIterGVN phase to identify nodes that must be // processed. A new worklist (with the updated node IDs) is returned in 'new_worklist'. // (2) Type information (the field PhaseGVN::_types) maps type information to each // node ID. The mapping is updated to use the new node IDs as well. Updated type // information is returned in PhaseGVN::_types. // // The PhaseRenumberLive phase does not preserve the order of elements in the worklist. // // Other data structures used by the compiler are not updated. The hash table for value // numbering (the field PhaseGVN::_table) is not updated because computing the hash // values is not based on node IDs. The field PhaseGVN::_nodes is not updated either // because it is empty wherever PhaseRenumberLive is used. PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn, Unique_Node_List* worklist, Unique_Node_List* new_worklist, PhaseNumber phase_num) : PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live) { assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place"); assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes"); assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point"); uint old_unique_count = C->unique(); uint live_node_count = C->live_nodes(); uint worklist_size = worklist->size(); // Storage for the updated type information. Type_Array new_type_array(C->comp_arena()); // Iterate over the set of live nodes. uint current_idx = 0; // The current new node ID. Incremented after every assignment. for (uint i = 0; i < _useful.size(); i++) { Node* n = _useful.at(i); // Sanity check that fails if we ever decide to execute this phase after EA assert(!n->is_Phi() || n->as_Phi()->inst_mem_id() == -1, "should not be linked to data Phi"); const Type* type = gvn->type_or_null(n); new_type_array.map(current_idx, type); bool in_worklist = false; if (worklist->member(n)) { in_worklist = true; } n->set_idx(current_idx); // Update node ID. if (in_worklist) { new_worklist->push(n); } current_idx++; } assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist"); assert(live_node_count == current_idx, "all live nodes must be processed"); // Replace the compiler's type information with the updated type information. gvn->replace_types(new_type_array); // Update the unique node count of the compilation to the number of currently live nodes. C->set_unique(live_node_count); // Set the dead node count to 0 and reset dead node list. C->reset_dead_node_list(); } //============================================================================= //------------------------------PhaseTransform--------------------------------- PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum), _arena(Thread::current()->resource_area()), _nodes(_arena), _types(_arena) { init_con_caches(); #ifndef PRODUCT clear_progress(); clear_transforms(); set_allow_progress(true); #endif // Force allocation for currently existing nodes _types.map(C->unique(), NULL); } //------------------------------PhaseTransform--------------------------------- PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum), _arena(arena), _nodes(arena), _types(arena) { init_con_caches(); #ifndef PRODUCT clear_progress(); clear_transforms(); set_allow_progress(true); #endif // Force allocation for currently existing nodes _types.map(C->unique(), NULL); } //------------------------------PhaseTransform--------------------------------- // Initialize with previously generated type information PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum), _arena(pt->_arena), _nodes(pt->_nodes), _types(pt->_types) { init_con_caches(); #ifndef PRODUCT clear_progress(); clear_transforms(); set_allow_progress(true); #endif } void PhaseTransform::init_con_caches() { memset(_icons,0,sizeof(_icons)); memset(_lcons,0,sizeof(_lcons)); memset(_zcons,0,sizeof(_zcons)); } //--------------------------------find_int_type-------------------------------- const TypeInt* PhaseTransform::find_int_type(Node* n) { if (n == NULL) return NULL; // Call type_or_null(n) to determine node's type since we might be in // parse phase and call n->Value() may return wrong type. // (For example, a phi node at the beginning of loop parsing is not ready.) const Type* t = type_or_null(n); if (t == NULL) return NULL; return t->isa_int(); } //-------------------------------find_long_type-------------------------------- const TypeLong* PhaseTransform::find_long_type(Node* n) { if (n == NULL) return NULL; // (See comment above on type_or_null.) const Type* t = type_or_null(n); if (t == NULL) return NULL; return t->isa_long(); } #ifndef PRODUCT void PhaseTransform::dump_old2new_map() const { _nodes.dump(); } void PhaseTransform::dump_new( uint nidx ) const { for( uint i=0; i<_nodes.Size(); i++ ) if( _nodes[i] && _nodes[i]->_idx == nidx ) { _nodes[i]->dump(); tty->cr(); tty->print_cr("Old index= %d",i); return; } tty->print_cr("Node %d not found in the new indices", nidx); } //------------------------------dump_types------------------------------------- void PhaseTransform::dump_types( ) const { _types.dump(); } //------------------------------dump_nodes_and_types--------------------------- void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) { VectorSet visited(Thread::current()->resource_area()); dump_nodes_and_types_recur( root, depth, only_ctrl, visited ); } //------------------------------dump_nodes_and_types_recur--------------------- void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) { if( !n ) return; if( depth == 0 ) return; if( visited.test_set(n->_idx) ) return; for( uint i=0; ilen(); i++ ) { if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue; dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited ); } n->dump(); if (type_or_null(n) != NULL) { tty->print(" "); type(n)->dump(); tty->cr(); } } #endif //============================================================================= //------------------------------PhaseValues------------------------------------ // Set minimum table size to "255" PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) { NOT_PRODUCT( clear_new_values(); ) } //------------------------------PhaseValues------------------------------------ // Set minimum table size to "255" PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ), _table(&ptv->_table) { NOT_PRODUCT( clear_new_values(); ) } //------------------------------PhaseValues------------------------------------ // Used by +VerifyOpto. Clear out hash table but copy _types array. PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ), _table(ptv->arena(),ptv->_table.size()) { NOT_PRODUCT( clear_new_values(); ) } //------------------------------~PhaseValues----------------------------------- #ifndef PRODUCT PhaseValues::~PhaseValues() { _table.dump(); // Statistics for value progress and efficiency if( PrintCompilation && Verbose && WizardMode ) { tty->print("\n%sValues: %d nodes ---> %d/%d (%d)", is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values()); if( made_transforms() != 0 ) { tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() ); } else { tty->cr(); } } } #endif //------------------------------makecon---------------------------------------- ConNode* PhaseTransform::makecon(const Type *t) { assert(t->singleton(), "must be a constant"); assert(!t->empty() || t == Type::TOP, "must not be vacuous range"); switch (t->base()) { // fast paths case Type::Half: case Type::Top: return (ConNode*) C->top(); case Type::Int: return intcon( t->is_int()->get_con() ); case Type::Long: return longcon( t->is_long()->get_con() ); } if (t->is_zero_type()) return zerocon(t->basic_type()); return uncached_makecon(t); } //--------------------------uncached_makecon----------------------------------- // Make an idealized constant - one of ConINode, ConPNode, etc. ConNode* PhaseValues::uncached_makecon(const Type *t) { assert(t->singleton(), "must be a constant"); ConNode* x = ConNode::make(C, t); ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering if (k == NULL) { set_type(x, t); // Missed, provide type mapping GrowableArray* nna = C->node_note_array(); if (nna != NULL) { Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true); loc->clear(); // do not put debug info on constants } } else { x->destruct(); // Hit, destroy duplicate constant x = k; // use existing constant } return x; } //------------------------------intcon----------------------------------------- // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))" ConINode* PhaseTransform::intcon(int i) { // Small integer? Check cache! Check that cached node is not dead if (i >= _icon_min && i <= _icon_max) { ConINode* icon = _icons[i-_icon_min]; if (icon != NULL && icon->in(TypeFunc::Control) != NULL) return icon; } ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i)); assert(icon->is_Con(), ""); if (i >= _icon_min && i <= _icon_max) _icons[i-_icon_min] = icon; // Cache small integers return icon; } //------------------------------longcon---------------------------------------- // Fast long constant. ConLNode* PhaseTransform::longcon(jlong l) { // Small integer? Check cache! Check that cached node is not dead if (l >= _lcon_min && l <= _lcon_max) { ConLNode* lcon = _lcons[l-_lcon_min]; if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL) return lcon; } ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l)); assert(lcon->is_Con(), ""); if (l >= _lcon_min && l <= _lcon_max) _lcons[l-_lcon_min] = lcon; // Cache small integers return lcon; } //------------------------------zerocon----------------------------------------- // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))" ConNode* PhaseTransform::zerocon(BasicType bt) { assert((uint)bt <= _zcon_max, "domain check"); ConNode* zcon = _zcons[bt]; if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL) return zcon; zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt)); _zcons[bt] = zcon; return zcon; } //============================================================================= //------------------------------transform-------------------------------------- // Return a node which computes the same function as this node, but in a // faster or cheaper fashion. Node *PhaseGVN::transform( Node *n ) { return transform_no_reclaim(n); } //------------------------------transform-------------------------------------- // Return a node which computes the same function as this node, but // in a faster or cheaper fashion. Node *PhaseGVN::transform_no_reclaim( Node *n ) { NOT_PRODUCT( set_transforms(); ) // Apply the Ideal call in a loop until it no longer applies Node *k = n; NOT_PRODUCT( uint loop_count = 0; ) while( 1 ) { Node *i = k->Ideal(this, /*can_reshape=*/false); if( !i ) break; assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" ); k = i; assert(loop_count++ < K, "infinite loop in PhaseGVN::transform"); } NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } ) // If brand new node, make space in type array. ensure_type_or_null(k); // Since I just called 'Value' to compute the set of run-time values // for this Node, and 'Value' is non-local (and therefore expensive) I'll // cache Value. Later requests for the local phase->type of this Node can // use the cached Value instead of suffering with 'bottom_type'. const Type *t = k->Value(this); // Get runtime Value set assert(t != NULL, "value sanity"); if (type_or_null(k) != t) { #ifndef PRODUCT // Do not count initial visit to node as a transformation if (type_or_null(k) == NULL) { inc_new_values(); set_progress(); } #endif set_type(k, t); // If k is a TypeNode, capture any more-precise type permanently into Node k->raise_bottom_type(t); } if( t->singleton() && !k->is_Con() ) { NOT_PRODUCT( set_progress(); ) return makecon(t); // Turn into a constant } // Now check for Identities Node *i = k->Identity(this); // Look for a nearby replacement if( i != k ) { // Found? Return replacement! NOT_PRODUCT( set_progress(); ) return i; } // Global Value Numbering i = hash_find_insert(k); // Insert if new if( i && (i != k) ) { // Return the pre-existing node NOT_PRODUCT( set_progress(); ) return i; } // Return Idealized original return k; } #ifdef ASSERT //------------------------------dead_loop_check-------------------------------- // Check for a simple dead loop when a data node references itself directly // or through an other data node excluding cons and phis. void PhaseGVN::dead_loop_check( Node *n ) { // Phi may reference itself in a loop if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) { // Do 2 levels check and only data inputs. bool no_dead_loop = true; uint cnt = n->req(); for (uint i = 1; i < cnt && no_dead_loop; i++) { Node *in = n->in(i); if (in == n) { no_dead_loop = false; } else if (in != NULL && !in->is_dead_loop_safe()) { uint icnt = in->req(); for (uint j = 1; j < icnt && no_dead_loop; j++) { if (in->in(j) == n || in->in(j) == in) no_dead_loop = false; } } } if (!no_dead_loop) n->dump(3); assert(no_dead_loop, "dead loop detected"); } } #endif //============================================================================= //------------------------------PhaseIterGVN----------------------------------- // Initialize hash table to fresh and clean for +VerifyOpto PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ), _stack(C->live_nodes() >> 1), _delay_transform(false) { } //------------------------------PhaseIterGVN----------------------------------- // Initialize with previous PhaseIterGVN info; used by PhaseCCP PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn), _worklist( igvn->_worklist ), _stack( igvn->_stack ), _delay_transform(igvn->_delay_transform) { } //------------------------------PhaseIterGVN----------------------------------- // Initialize with previous PhaseGVN info from Parser PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn), _worklist(*C->for_igvn()), // TODO: Before incremental inlining it was allocated only once and it was fine. Now that // the constructor is used in incremental inlining, this consumes too much memory: // _stack(C->live_nodes() >> 1), // So, as a band-aid, we replace this by: _stack(C->comp_arena(), 32), _delay_transform(false) { uint max; // Dead nodes in the hash table inherited from GVN were not treated as // roots during def-use info creation; hence they represent an invisible // use. Clear them out. max = _table.size(); for( uint i = 0; i < max; ++i ) { Node *n = _table.at(i); if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) { if( n->is_top() ) continue; assert( false, "Parse::remove_useless_nodes missed this node"); hash_delete(n); } } // Any Phis or Regions on the worklist probably had uses that could not // make more progress because the uses were made while the Phis and Regions // were in half-built states. Put all uses of Phis and Regions on worklist. max = _worklist.size(); for( uint j = 0; j < max; j++ ) { Node *n = _worklist.at(j); uint uop = n->Opcode(); if( uop == Op_Phi || uop == Op_Region || n->is_Type() || n->is_Mem() ) add_users_to_worklist(n); } } #ifndef PRODUCT void PhaseIterGVN::verify_step(Node* n) { _verify_window[_verify_counter % _verify_window_size] = n; ++_verify_counter; ResourceMark rm; ResourceArea *area = Thread::current()->resource_area(); VectorSet old_space(area), new_space(area); if (C->unique() < 1000 || 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) { ++_verify_full_passes; Node::verify_recur(C->root(), -1, old_space, new_space); } const int verify_depth = 4; for ( int i = 0; i < _verify_window_size; i++ ) { Node* n = _verify_window[i]; if ( n == NULL ) continue; if( n->in(0) == NodeSentinel ) { // xform_idom _verify_window[i] = n->in(1); --i; continue; } // Typical fanout is 1-2, so this call visits about 6 nodes. Node::verify_recur(n, verify_depth, old_space, new_space); } } #endif //------------------------------init_worklist---------------------------------- // Initialize worklist for each node. void PhaseIterGVN::init_worklist( Node *n ) { if( _worklist.member(n) ) return; _worklist.push(n); uint cnt = n->req(); for( uint i =0 ; i < cnt; i++ ) { Node *m = n->in(i); if( m ) init_worklist(m); } } //------------------------------optimize--------------------------------------- void PhaseIterGVN::optimize() { debug_only(uint num_processed = 0;); #ifndef PRODUCT { _verify_counter = 0; _verify_full_passes = 0; for ( int i = 0; i < _verify_window_size; i++ ) { _verify_window[i] = NULL; } } #endif #ifdef ASSERT Node* prev = NULL; uint rep_cnt = 0; #endif uint loop_count = 0; // Pull from worklist; transform node; // If node has changed: update edge info and put uses on worklist. while( _worklist.size() ) { if (C->check_node_count(NodeLimitFudgeFactor * 2, "out of nodes optimizing method")) { return; } Node *n = _worklist.pop(); if (++loop_count >= K * C->live_nodes()) { debug_only(n->dump(4);) assert(false, "infinite loop in PhaseIterGVN::optimize"); C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize"); return; } #ifdef ASSERT if (n == prev) { if (++rep_cnt > 3) { n->dump(4); assert(false, "loop in Ideal transformation"); } } else { rep_cnt = 0; } prev = n; #endif if (TraceIterativeGVN && Verbose) { tty->print(" Pop "); NOT_PRODUCT( n->dump(); ) debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();) } if (n->outcnt() != 0) { #ifndef PRODUCT uint wlsize = _worklist.size(); const Type* oldtype = type_or_null(n); #endif //PRODUCT Node *nn = transform_old(n); #ifndef PRODUCT if (TraceIterativeGVN) { const Type* newtype = type_or_null(n); if (nn != n) { // print old node tty->print("< "); if (oldtype != newtype && oldtype != NULL) { oldtype->dump(); } do { tty->print("\t"); } while (tty->position() < 16); tty->print("<"); n->dump(); } if (oldtype != newtype || nn != n) { // print new node and/or new type if (oldtype == NULL) { tty->print("* "); } else if (nn != n) { tty->print("> "); } else { tty->print("= "); } if (newtype == NULL) { tty->print("null"); } else { newtype->dump(); } do { tty->print("\t"); } while (tty->position() < 16); nn->dump(); } if (Verbose && wlsize < _worklist.size()) { tty->print(" Push {"); while (wlsize != _worklist.size()) { Node* pushed = _worklist.at(wlsize++); tty->print(" %d", pushed->_idx); } tty->print_cr(" }"); } } if( VerifyIterativeGVN && nn != n ) { verify_step((Node*) NULL); // ignore n, it might be subsumed } #endif } else if (!n->is_top()) { remove_dead_node(n); } } #ifndef PRODUCT C->verify_graph_edges(); if( VerifyOpto && allow_progress() ) { // Must turn off allow_progress to enable assert and break recursion C->root()->verify(); { // Check if any progress was missed using IterGVN // Def-Use info enables transformations not attempted in wash-pass // e.g. Region/Phi cleanup, ... // Null-check elision -- may not have reached fixpoint // do not propagate to dominated nodes ResourceMark rm; PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean! // Fill worklist completely igvn2.init_worklist(C->root()); igvn2.set_allow_progress(false); igvn2.optimize(); igvn2.set_allow_progress(true); } } if ( VerifyIterativeGVN && PrintOpto ) { if ( _verify_counter == _verify_full_passes ) tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes", (int) _verify_full_passes); else tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes", (int) _verify_counter, (int) _verify_full_passes); } #endif } //------------------register_new_node_with_optimizer--------------------------- // Register a new node with the optimizer. Update the types array, the def-use // info. Put on worklist. Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) { set_type_bottom(n); _worklist.push(n); if (orig != NULL) C->copy_node_notes_to(n, orig); return n; } //------------------------------transform-------------------------------------- // Non-recursive: idealize Node 'n' with respect to its inputs and its value Node *PhaseIterGVN::transform( Node *n ) { if (_delay_transform) { // Register the node but don't optimize for now register_new_node_with_optimizer(n); return n; } // If brand new node, make space in type array, and give it a type. ensure_type_or_null(n); if (type_or_null(n) == NULL) { set_type_bottom(n); } return transform_old(n); } //------------------------------transform_old---------------------------------- Node *PhaseIterGVN::transform_old( Node *n ) { #ifndef PRODUCT debug_only(uint loop_count = 0;); set_transforms(); #endif // Remove 'n' from hash table in case it gets modified _table.hash_delete(n); if( VerifyIterativeGVN ) { assert( !_table.find_index(n->_idx), "found duplicate entry in table"); } // Apply the Ideal call in a loop until it no longer applies Node *k = n; DEBUG_ONLY(dead_loop_check(k);) DEBUG_ONLY(bool is_new = (k->outcnt() == 0);) Node *i = k->Ideal(this, /*can_reshape=*/true); assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); #ifndef PRODUCT if( VerifyIterativeGVN ) verify_step(k); if( i && VerifyOpto ) { if( !allow_progress() ) { if (i->is_Add() && i->outcnt() == 1) { // Switched input to left side because this is the only use } else if( i->is_If() && (i->in(0) == NULL) ) { // This IF is dead because it is dominated by an equivalent IF When // dominating if changed, info is not propagated sparsely to 'this' // Propagating this info further will spuriously identify other // progress. return i; } else set_progress(); } else set_progress(); } #endif while( i ) { #ifndef PRODUCT debug_only( if( loop_count >= K ) i->dump(4); ) assert(loop_count < K, "infinite loop in PhaseIterGVN::transform"); debug_only( loop_count++; ) #endif assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes"); // Made a change; put users of original Node on worklist add_users_to_worklist( k ); // Replacing root of transform tree? if( k != i ) { // Make users of old Node now use new. subsume_node( k, i ); k = i; } DEBUG_ONLY(dead_loop_check(k);) // Try idealizing again DEBUG_ONLY(is_new = (k->outcnt() == 0);) i = k->Ideal(this, /*can_reshape=*/true); assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); #ifndef PRODUCT if( VerifyIterativeGVN ) verify_step(k); if( i && VerifyOpto ) set_progress(); #endif } // If brand new node, make space in type array. ensure_type_or_null(k); // See what kind of values 'k' takes on at runtime const Type *t = k->Value(this); assert(t != NULL, "value sanity"); // Since I just called 'Value' to compute the set of run-time values // for this Node, and 'Value' is non-local (and therefore expensive) I'll // cache Value. Later requests for the local phase->type of this Node can // use the cached Value instead of suffering with 'bottom_type'. if (t != type_or_null(k)) { NOT_PRODUCT( set_progress(); ) NOT_PRODUCT( inc_new_values();) set_type(k, t); // If k is a TypeNode, capture any more-precise type permanently into Node k->raise_bottom_type(t); // Move users of node to worklist add_users_to_worklist( k ); } // If 'k' computes a constant, replace it with a constant if( t->singleton() && !k->is_Con() ) { NOT_PRODUCT( set_progress(); ) Node *con = makecon(t); // Make a constant add_users_to_worklist( k ); subsume_node( k, con ); // Everybody using k now uses con return con; } // Now check for Identities i = k->Identity(this); // Look for a nearby replacement if( i != k ) { // Found? Return replacement! NOT_PRODUCT( set_progress(); ) add_users_to_worklist( k ); subsume_node( k, i ); // Everybody using k now uses i return i; } // Global Value Numbering i = hash_find_insert(k); // Check for pre-existing node if( i && (i != k) ) { // Return the pre-existing node if it isn't dead NOT_PRODUCT( set_progress(); ) add_users_to_worklist( k ); subsume_node( k, i ); // Everybody using k now uses i return i; } // Return Idealized original return k; } //---------------------------------saturate------------------------------------ const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type, const Type* limit_type) const { return new_type->narrow(old_type); } //------------------------------remove_globally_dead_node---------------------- // Kill a globally dead Node. All uses are also globally dead and are // aggressively trimmed. void PhaseIterGVN::remove_globally_dead_node( Node *dead ) { enum DeleteProgress { PROCESS_INPUTS, PROCESS_OUTPUTS }; assert(_stack.is_empty(), "not empty"); _stack.push(dead, PROCESS_INPUTS); while (_stack.is_nonempty()) { dead = _stack.node(); uint progress_state = _stack.index(); assert(dead != C->root(), "killing root, eh?"); assert(!dead->is_top(), "add check for top when pushing"); NOT_PRODUCT( set_progress(); ) if (progress_state == PROCESS_INPUTS) { // After following inputs, continue to outputs _stack.set_index(PROCESS_OUTPUTS); if (!dead->is_Con()) { // Don't kill cons but uses bool recurse = false; // Remove from hash table _table.hash_delete( dead ); // Smash all inputs to 'dead', isolating him completely for (uint i = 0; i < dead->req(); i++) { Node *in = dead->in(i); if (in != NULL && in != C->top()) { // Points to something? int nrep = dead->replace_edge(in, NULL); // Kill edges assert((nrep > 0), "sanity"); if (in->outcnt() == 0) { // Made input go dead? _stack.push(in, PROCESS_INPUTS); // Recursively remove recurse = true; } else if (in->outcnt() == 1 && in->has_special_unique_user()) { _worklist.push(in->unique_out()); } else if (in->outcnt() <= 2 && dead->is_Phi()) { if (in->Opcode() == Op_Region) { _worklist.push(in); } else if (in->is_Store()) { DUIterator_Fast imax, i = in->fast_outs(imax); _worklist.push(in->fast_out(i)); i++; if (in->outcnt() == 2) { _worklist.push(in->fast_out(i)); i++; } assert(!(i < imax), "sanity"); } } if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory && in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) { // A Load that directly follows an InitializeNode is // going away. The Stores that follow are candidates // again to be captured by the InitializeNode. for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) { Node *n = in->fast_out(j); if (n->is_Store()) { _worklist.push(n); } } } } // if (in != NULL && in != C->top()) } // for (uint i = 0; i < dead->req(); i++) if (recurse) { continue; } } // if (!dead->is_Con()) } // if (progress_state == PROCESS_INPUTS) // Aggressively kill globally dead uses // (Rather than pushing all the outs at once, we push one at a time, // plus the parent to resume later, because of the indefinite number // of edge deletions per loop trip.) if (dead->outcnt() > 0) { // Recursively remove output edges _stack.push(dead->raw_out(0), PROCESS_INPUTS); } else { // Finished disconnecting all input and output edges. _stack.pop(); // Remove dead node from iterative worklist _worklist.remove(dead); // Constant node that has no out-edges and has only one in-edge from // root is usually dead. However, sometimes reshaping walk makes // it reachable by adding use edges. So, we will NOT count Con nodes // as dead to be conservative about the dead node count at any // given time. if (!dead->is_Con()) { C->record_dead_node(dead->_idx); } if (dead->is_macro()) { C->remove_macro_node(dead); } if (dead->is_expensive()) { C->remove_expensive_node(dead); } CastIINode* cast = dead->isa_CastII(); if (cast != NULL && cast->has_range_check()) { C->remove_range_check_cast(cast); } } } // while (_stack.is_nonempty()) } //------------------------------subsume_node----------------------------------- // Remove users from node 'old' and add them to node 'nn'. void PhaseIterGVN::subsume_node( Node *old, Node *nn ) { assert( old != hash_find(old), "should already been removed" ); assert( old != C->top(), "cannot subsume top node"); // Copy debug or profile information to the new version: C->copy_node_notes_to(nn, old); // Move users of node 'old' to node 'nn' for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) { Node* use = old->last_out(i); // for each use... // use might need re-hashing (but it won't if it's a new node) bool is_in_table = _table.hash_delete( use ); // Update use-def info as well // We remove all occurrences of old within use->in, // so as to avoid rehashing any node more than once. // The hash table probe swamps any outer loop overhead. uint num_edges = 0; for (uint jmax = use->len(), j = 0; j < jmax; j++) { if (use->in(j) == old) { use->set_req(j, nn); ++num_edges; } } // Insert into GVN hash table if unique // If a duplicate, 'use' will be cleaned up when pulled off worklist if( is_in_table ) { hash_find_insert(use); } i -= num_edges; // we deleted 1 or more copies of this edge } // Search for instance field data PhiNodes in the same region pointing to the old // memory PhiNode and update their instance memory ids to point to the new node. if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) { Node* region = old->in(0); for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { PhiNode* phi = region->fast_out(i)->isa_Phi(); if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) { phi->set_inst_mem_id((int)nn->_idx); } } } // Smash all inputs to 'old', isolating him completely Node *temp = new (C) Node(1); temp->init_req(0,nn); // Add a use to nn to prevent him from dying remove_dead_node( old ); temp->del_req(0); // Yank bogus edge #ifndef PRODUCT if( VerifyIterativeGVN ) { for ( int i = 0; i < _verify_window_size; i++ ) { if ( _verify_window[i] == old ) _verify_window[i] = nn; } } #endif _worklist.remove(temp); // this can be necessary temp->destruct(); // reuse the _idx of this little guy } //------------------------------add_users_to_worklist-------------------------- void PhaseIterGVN::add_users_to_worklist0( Node *n ) { for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { _worklist.push(n->fast_out(i)); // Push on worklist } } // Return counted loop Phi if as a counted loop exit condition, cmp // compares the the induction variable with n static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) { for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) { Node* bol = cmp->fast_out(i); for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) { Node* iff = bol->fast_out(i2); if (iff->is_CountedLoopEnd()) { CountedLoopEndNode* cle = iff->as_CountedLoopEnd(); if (cle->limit() == n) { PhiNode* phi = cle->phi(); if (phi != NULL) { return phi; } } } } } return NULL; } void PhaseIterGVN::add_users_to_worklist( Node *n ) { add_users_to_worklist0(n); // Move users of node to worklist for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { Node* use = n->fast_out(i); // Get use if( use->is_Multi() || // Multi-definer? Push projs on worklist use->is_Store() ) // Enable store/load same address add_users_to_worklist0(use); // If we changed the receiver type to a call, we need to revisit // the Catch following the call. It's looking for a non-NULL // receiver to know when to enable the regular fall-through path // in addition to the NullPtrException path. if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) { Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control); if (p != NULL) { add_users_to_worklist0(p); } } uint use_op = use->Opcode(); if(use->is_Cmp()) { // Enable CMP/BOOL optimization add_users_to_worklist(use); // Put Bool on worklist if (use->outcnt() > 0) { Node* bol = use->raw_out(0); if (bol->outcnt() > 0) { Node* iff = bol->raw_out(0); if (iff->outcnt() == 2) { // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the // phi merging either 0 or 1 onto the worklist Node* ifproj0 = iff->raw_out(0); Node* ifproj1 = iff->raw_out(1); if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) { Node* region0 = ifproj0->raw_out(0); Node* region1 = ifproj1->raw_out(0); if( region0 == region1 ) add_users_to_worklist0(region0); } } } } if (use_op == Op_CmpI) { Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n); if (phi != NULL) { // If an opaque node feeds into the limit condition of a // CountedLoop, we need to process the Phi node for the // induction variable when the opaque node is removed: // the range of values taken by the Phi is now known and // so its type is also known. _worklist.push(phi); } Node* in1 = use->in(1); for (uint i = 0; i < in1->outcnt(); i++) { if (in1->raw_out(i)->Opcode() == Op_CastII) { Node* castii = in1->raw_out(i); if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) { Node* ifnode = castii->in(0)->in(0); if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) { // Reprocess a CastII node that may depend on an // opaque node value when the opaque node is // removed. In case it carries a dependency we can do // a better job of computing its type. _worklist.push(castii); } } } } } } // If changed Cast input, check Phi users for simple cycles if( use->is_ConstraintCast() || use->is_CheckCastPP() ) { for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { Node* u = use->fast_out(i2); if (u->is_Phi()) _worklist.push(u); } } // If changed LShift inputs, check RShift users for useless sign-ext if( use_op == Op_LShiftI ) { for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { Node* u = use->fast_out(i2); if (u->Opcode() == Op_RShiftI) _worklist.push(u); } } // If changed AddI/SubI inputs, check CmpU for range check optimization. if (use_op == Op_AddI || use_op == Op_SubI) { for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { Node* u = use->fast_out(i2); if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) { _worklist.push(u); } } } // If changed AddP inputs, check Stores for loop invariant if( use_op == Op_AddP ) { for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { Node* u = use->fast_out(i2); if (u->is_Mem()) _worklist.push(u); } } // If changed initialization activity, check dependent Stores if (use_op == Op_Allocate || use_op == Op_AllocateArray) { InitializeNode* init = use->as_Allocate()->initialization(); if (init != NULL) { Node* imem = init->proj_out(TypeFunc::Memory); if (imem != NULL) add_users_to_worklist0(imem); } } if (use_op == Op_Initialize) { Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory); if (imem != NULL) add_users_to_worklist0(imem); } } } /** * Remove the speculative part of all types that we know of */ void PhaseIterGVN::remove_speculative_types() { assert(UseTypeSpeculation, "speculation is off"); for (uint i = 0; i < _types.Size(); i++) { const Type* t = _types.fast_lookup(i); if (t != NULL) { _types.map(i, t->remove_speculative()); } } _table.check_no_speculative_types(); } //============================================================================= #ifndef PRODUCT uint PhaseCCP::_total_invokes = 0; uint PhaseCCP::_total_constants = 0; #endif //------------------------------PhaseCCP--------------------------------------- // Conditional Constant Propagation, ala Wegman & Zadeck PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) { NOT_PRODUCT( clear_constants(); ) assert( _worklist.size() == 0, "" ); // Clear out _nodes from IterGVN. Must be clear to transform call. _nodes.clear(); // Clear out from IterGVN analyze(); } #ifndef PRODUCT //------------------------------~PhaseCCP-------------------------------------- PhaseCCP::~PhaseCCP() { inc_invokes(); _total_constants += count_constants(); } #endif #ifdef ASSERT static bool ccp_type_widens(const Type* t, const Type* t0) { assert(t->meet(t0) == t, "Not monotonic"); switch (t->base() == t0->base() ? t->base() : Type::Top) { case Type::Int: assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases"); break; case Type::Long: assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases"); break; } return true; } #endif //ASSERT //------------------------------analyze---------------------------------------- void PhaseCCP::analyze() { // Initialize all types to TOP, optimistic analysis for (int i = C->unique() - 1; i >= 0; i--) { _types.map(i,Type::TOP); } // Push root onto worklist Unique_Node_List worklist; worklist.push(C->root()); // Pull from worklist; compute new value; push changes out. // This loop is the meat of CCP. while( worklist.size() ) { Node *n = worklist.pop(); const Type *t = n->Value(this); if (t != type(n)) { assert(ccp_type_widens(t, type(n)), "ccp type must widen"); #ifndef PRODUCT if( TracePhaseCCP ) { t->dump(); do { tty->print("\t"); } while (tty->position() < 16); n->dump(); } #endif set_type(n, t); for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { Node* m = n->fast_out(i); // Get user if (m->is_Region()) { // New path to Region? Must recheck Phis too for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { Node* p = m->fast_out(i2); // Propagate changes to uses if (p->bottom_type() != type(p)) { // If not already bottomed out worklist.push(p); // Propagate change to user } } } // If we changed the receiver type to a call, we need to revisit // the Catch following the call. It's looking for a non-NULL // receiver to know when to enable the regular fall-through path // in addition to the NullPtrException path if (m->is_Call()) { for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { Node* p = m->fast_out(i2); // Propagate changes to uses if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) { worklist.push(p->unique_out()); } } } if (m->bottom_type() != type(m)) { // If not already bottomed out worklist.push(m); // Propagate change to user } // CmpU nodes can get their type information from two nodes up in the // graph (instead of from the nodes immediately above). Make sure they // are added to the worklist if nodes they depend on are updated, since // they could be missed and get wrong types otherwise. uint m_op = m->Opcode(); if (m_op == Op_AddI || m_op == Op_SubI) { for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { Node* p = m->fast_out(i2); // Propagate changes to uses if (p->Opcode() == Op_CmpU) { // Got a CmpU which might need the new type information from node n. if(p->bottom_type() != type(p)) { // If not already bottomed out worklist.push(p); // Propagate change to user } } } } // If n is used in a counted loop exit condition then the type // of the counted loop's Phi depends on the type of n. See // PhiNode::Value(). if (m_op == Op_CmpI) { PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n); if (phi != NULL) { worklist.push(phi); } } } } } } //------------------------------do_transform----------------------------------- // Top level driver for the recursive transformer void PhaseCCP::do_transform() { // Correct leaves of new-space Nodes; they point to old-space. C->set_root( transform(C->root())->as_Root() ); assert( C->top(), "missing TOP node" ); assert( C->root(), "missing root" ); } //------------------------------transform-------------------------------------- // Given a Node in old-space, clone him into new-space. // Convert any of his old-space children into new-space children. Node *PhaseCCP::transform( Node *n ) { Node *new_node = _nodes[n->_idx]; // Check for transformed node if( new_node != NULL ) return new_node; // Been there, done that, return old answer new_node = transform_once(n); // Check for constant _nodes.map( n->_idx, new_node ); // Flag as having been cloned // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc GrowableArray trstack(C->live_nodes() >> 1); trstack.push(new_node); // Process children of cloned node while ( trstack.is_nonempty() ) { Node *clone = trstack.pop(); uint cnt = clone->req(); for( uint i = 0; i < cnt; i++ ) { // For all inputs do Node *input = clone->in(i); if( input != NULL ) { // Ignore NULLs Node *new_input = _nodes[input->_idx]; // Check for cloned input node if( new_input == NULL ) { new_input = transform_once(input); // Check for constant _nodes.map( input->_idx, new_input );// Flag as having been cloned trstack.push(new_input); } assert( new_input == clone->in(i), "insanity check"); } } } return new_node; } //------------------------------transform_once--------------------------------- // For PhaseCCP, transformation is IDENTITY unless Node computed a constant. Node *PhaseCCP::transform_once( Node *n ) { const Type *t = type(n); // Constant? Use constant Node instead if( t->singleton() ) { Node *nn = n; // Default is to return the original constant if( t == Type::TOP ) { // cache my top node on the Compile instance if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) { C->set_cached_top_node( ConNode::make(C, Type::TOP) ); set_type(C->top(), Type::TOP); } nn = C->top(); } if( !n->is_Con() ) { if( t != Type::TOP ) { nn = makecon(t); // ConNode::make(t); NOT_PRODUCT( inc_constants(); ) } else if( n->is_Region() ) { // Unreachable region // Note: nn == C->top() n->set_req(0, NULL); // Cut selfreference // Eagerly remove dead phis to avoid phis copies creation. for (DUIterator i = n->outs(); n->has_out(i); i++) { Node* m = n->out(i); if( m->is_Phi() ) { assert(type(m) == Type::TOP, "Unreachable region should not have live phis."); replace_node(m, nn); --i; // deleted this phi; rescan starting with next position } } } replace_node(n,nn); // Update DefUse edges for new constant } return nn; } // If x is a TypeNode, capture any more-precise type permanently into Node if (t != n->bottom_type()) { hash_delete(n); // changing bottom type may force a rehash n->raise_bottom_type(t); _worklist.push(n); // n re-enters the hash table via the worklist } // Idealize graph using DU info. Must clone() into new-space. // DU info is generally used to show profitability, progress or safety // (but generally not needed for correctness). Node *nn = n->Ideal_DU_postCCP(this); // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks switch( n->Opcode() ) { case Op_FastLock: // Revisit FastLocks for lock coarsening case Op_If: case Op_CountedLoopEnd: case Op_Region: case Op_Loop: case Op_CountedLoop: case Op_Conv2B: case Op_Opaque1: case Op_Opaque2: _worklist.push(n); break; default: break; } if( nn ) { _worklist.push(n); // Put users of 'n' onto worklist for second igvn transform add_users_to_worklist(n); return nn; } return n; } //---------------------------------saturate------------------------------------ const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type, const Type* limit_type) const { const Type* wide_type = new_type->widen(old_type, limit_type); if (wide_type != new_type) { // did we widen? // If so, we may have widened beyond the limit type. Clip it back down. new_type = wide_type->filter(limit_type); } return new_type; } //------------------------------print_statistics------------------------------- #ifndef PRODUCT void PhaseCCP::print_statistics() { tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants); } #endif //============================================================================= #ifndef PRODUCT uint PhasePeephole::_total_peepholes = 0; #endif //------------------------------PhasePeephole---------------------------------- // Conditional Constant Propagation, ala Wegman & Zadeck PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg ) : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) { NOT_PRODUCT( clear_peepholes(); ) } #ifndef PRODUCT //------------------------------~PhasePeephole--------------------------------- PhasePeephole::~PhasePeephole() { _total_peepholes += count_peepholes(); } #endif //------------------------------transform-------------------------------------- Node *PhasePeephole::transform( Node *n ) { ShouldNotCallThis(); return NULL; } //------------------------------do_transform----------------------------------- void PhasePeephole::do_transform() { bool method_name_not_printed = true; // Examine each basic block for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) { Block* block = _cfg.get_block(block_number); bool block_not_printed = true; // and each instruction within a block uint end_index = block->number_of_nodes(); // block->end_idx() not valid after PhaseRegAlloc for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) { Node *n = block->get_node(instruction_index); if( n->is_Mach() ) { MachNode *m = n->as_Mach(); int deleted_count = 0; // check for peephole opportunities MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C ); if( m2 != NULL ) { #ifndef PRODUCT if( PrintOptoPeephole ) { // Print method, first time only if( C->method() && method_name_not_printed ) { C->method()->print_short_name(); tty->cr(); method_name_not_printed = false; } // Print this block if( Verbose && block_not_printed) { tty->print_cr("in block"); block->dump(); block_not_printed = false; } // Print instructions being deleted for( int i = (deleted_count - 1); i >= 0; --i ) { block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr(); } tty->print_cr("replaced with"); // Print new instruction m2->format(_regalloc); tty->print("\n\n"); } #endif // Remove old nodes from basic block and update instruction_index // (old nodes still exist and may have edges pointing to them // as register allocation info is stored in the allocator using // the node index to live range mappings.) uint safe_instruction_index = (instruction_index - deleted_count); for( ; (instruction_index > safe_instruction_index); --instruction_index ) { block->remove_node( instruction_index ); } // install new node after safe_instruction_index block->insert_node(m2, safe_instruction_index + 1); end_index = block->number_of_nodes() - 1; // Recompute new block size NOT_PRODUCT( inc_peepholes(); ) } } } } } //------------------------------print_statistics------------------------------- #ifndef PRODUCT void PhasePeephole::print_statistics() { tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes); } #endif //============================================================================= //------------------------------set_req_X-------------------------------------- void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) { assert( is_not_dead(n), "can not use dead node"); assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" ); Node *old = in(i); set_req(i, n); // old goes dead? if( old ) { switch (old->outcnt()) { case 0: // Put into the worklist to kill later. We do not kill it now because the // recursive kill will delete the current node (this) if dead-loop exists if (!old->is_top()) igvn->_worklist.push( old ); break; case 1: if( old->is_Store() || old->has_special_unique_user() ) igvn->add_users_to_worklist( old ); break; case 2: if( old->is_Store() ) igvn->add_users_to_worklist( old ); if( old->Opcode() == Op_Region ) igvn->_worklist.push(old); break; case 3: if( old->Opcode() == Op_Region ) { igvn->_worklist.push(old); igvn->add_users_to_worklist( old ); } break; default: break; } } } //-------------------------------replace_by----------------------------------- // Using def-use info, replace one node for another. Follow the def-use info // to all users of the OLD node. Then make all uses point to the NEW node. void Node::replace_by(Node *new_node) { assert(!is_top(), "top node has no DU info"); for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) { Node* use = last_out(i); uint uses_found = 0; for (uint j = 0; j < use->len(); j++) { if (use->in(j) == this) { if (j < use->req()) use->set_req(j, new_node); else use->set_prec(j, new_node); uses_found++; } } i -= uses_found; // we deleted 1 or more copies of this edge } } //============================================================================= //----------------------------------------------------------------------------- void Type_Array::grow( uint i ) { if( !_max ) { _max = 1; _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) ); _types[0] = NULL; } uint old = _max; while( i >= _max ) _max <<= 1; // Double to fit _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*)); memset( &_types[old], 0, (_max-old)*sizeof(Type*) ); } //------------------------------dump------------------------------------------- #ifndef PRODUCT void Type_Array::dump() const { uint max = Size(); for( uint i = 0; i < max; i++ ) { if( _types[i] != NULL ) { tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr(); } } } #endif