Java example source code file (phaseX.cpp)
The phaseX.cpp Java example source code
/*
* Copyright (c) 1997, 2013, 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
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*/
#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; i<req; i++ )
if( n->in(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; i<req; i++ )
if( n->in(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
}
}
}
#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 ) : Phase(Remove_Useless),
_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;
}
}
}
}
//=============================================================================
//------------------------------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; i<n->len(); 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<Node_Notes*>* 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->unique() >> 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()),
_stack(C->unique() >> 1),
_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",
_verify_full_passes);
else
tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
_verify_counter, _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);
}
}
} // 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
}
// 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
}
}
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);
}
}
if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
add_users_to_worklist(use); // Put Bool on worklist
// Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
// phi merging either 0 or 1 onto the 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) {
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);
}
}
}
}
}
uint use_op = use->Opcode();
// 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 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 && t->isa_oopptr()) {
const TypeOopPtr* to = t->is_oopptr();
_types.map(i, to->remove_speculative());
}
}
}
//=============================================================================
#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
}
}
}
}
//------------------------------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 <Node *> trstack(C->unique() >> 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
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