Java example source code file (escape.cpp)
The escape.cpp Java example source code/*
* Copyright (c) 2005, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
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*/
#include "precompiled.hpp"
#include "ci/bcEscapeAnalyzer.hpp"
#include "compiler/compileLog.hpp"
#include "libadt/vectset.hpp"
#include "memory/allocation.hpp"
#include "opto/c2compiler.hpp"
#include "opto/callnode.hpp"
#include "opto/cfgnode.hpp"
#include "opto/compile.hpp"
#include "opto/escape.hpp"
#include "opto/phaseX.hpp"
#include "opto/rootnode.hpp"
ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
_nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
_collecting(true),
_verify(false),
_compile(C),
_igvn(igvn),
_node_map(C->comp_arena()) {
// Add unknown java object.
add_java_object(C->top(), PointsToNode::GlobalEscape);
phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
// Add ConP(#NULL) and ConN(#NULL) nodes.
Node* oop_null = igvn->zerocon(T_OBJECT);
assert(oop_null->_idx < nodes_size(), "should be created already");
add_java_object(oop_null, PointsToNode::NoEscape);
null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
if (UseCompressedOops) {
Node* noop_null = igvn->zerocon(T_NARROWOOP);
assert(noop_null->_idx < nodes_size(), "should be created already");
map_ideal_node(noop_null, null_obj);
}
_pcmp_neq = NULL; // Should be initialized
_pcmp_eq = NULL;
}
bool ConnectionGraph::has_candidates(Compile *C) {
// EA brings benefits only when the code has allocations and/or locks which
// are represented by ideal Macro nodes.
int cnt = C->macro_count();
for (int i = 0; i < cnt; i++) {
Node *n = C->macro_node(i);
if (n->is_Allocate())
return true;
if (n->is_Lock()) {
Node* obj = n->as_Lock()->obj_node()->uncast();
if (!(obj->is_Parm() || obj->is_Con()))
return true;
}
if (n->is_CallStaticJava() &&
n->as_CallStaticJava()->is_boxing_method()) {
return true;
}
}
return false;
}
void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
Compile::TracePhase t2("escapeAnalysis", &Phase::_t_escapeAnalysis, true);
ResourceMark rm;
// Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
// to create space for them in ConnectionGraph::_nodes[].
Node* oop_null = igvn->zerocon(T_OBJECT);
Node* noop_null = igvn->zerocon(T_NARROWOOP);
ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
// Perform escape analysis
if (congraph->compute_escape()) {
// There are non escaping objects.
C->set_congraph(congraph);
}
// Cleanup.
if (oop_null->outcnt() == 0)
igvn->hash_delete(oop_null);
if (noop_null->outcnt() == 0)
igvn->hash_delete(noop_null);
}
bool ConnectionGraph::compute_escape() {
Compile* C = _compile;
PhaseGVN* igvn = _igvn;
// Worklists used by EA.
Unique_Node_List delayed_worklist;
GrowableArray<Node*> alloc_worklist;
GrowableArray<Node*> ptr_cmp_worklist;
GrowableArray<Node*> storestore_worklist;
GrowableArray<PointsToNode*> ptnodes_worklist;
GrowableArray<JavaObjectNode*> java_objects_worklist;
GrowableArray<JavaObjectNode*> non_escaped_worklist;
GrowableArray<FieldNode*> oop_fields_worklist;
DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
{ Compile::TracePhase t3("connectionGraph", &Phase::_t_connectionGraph, true);
// 1. Populate Connection Graph (CG) with PointsTo nodes.
ideal_nodes.map(C->live_nodes(), NULL); // preallocate space
// Initialize worklist
if (C->root() != NULL) {
ideal_nodes.push(C->root());
}
for( uint next = 0; next < ideal_nodes.size(); ++next ) {
Node* n = ideal_nodes.at(next);
// Create PointsTo nodes and add them to Connection Graph. Called
// only once per ideal node since ideal_nodes is Unique_Node list.
add_node_to_connection_graph(n, &delayed_worklist);
PointsToNode* ptn = ptnode_adr(n->_idx);
if (ptn != NULL) {
ptnodes_worklist.append(ptn);
if (ptn->is_JavaObject()) {
java_objects_worklist.append(ptn->as_JavaObject());
if ((n->is_Allocate() || n->is_CallStaticJava()) &&
(ptn->escape_state() < PointsToNode::GlobalEscape)) {
// Only allocations and java static calls results are interesting.
non_escaped_worklist.append(ptn->as_JavaObject());
}
} else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
oop_fields_worklist.append(ptn->as_Field());
}
}
if (n->is_MergeMem()) {
// Collect all MergeMem nodes to add memory slices for
// scalar replaceable objects in split_unique_types().
_mergemem_worklist.append(n->as_MergeMem());
} else if (OptimizePtrCompare && n->is_Cmp() &&
(n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
// Collect compare pointers nodes.
ptr_cmp_worklist.append(n);
} else if (n->is_MemBarStoreStore()) {
// Collect all MemBarStoreStore nodes so that depending on the
// escape status of the associated Allocate node some of them
// may be eliminated.
storestore_worklist.append(n);
} else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
(n->req() > MemBarNode::Precedent)) {
record_for_optimizer(n);
#ifdef ASSERT
} else if (n->is_AddP()) {
// Collect address nodes for graph verification.
addp_worklist.append(n);
#endif
}
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node* m = n->fast_out(i); // Get user
ideal_nodes.push(m);
}
}
if (non_escaped_worklist.length() == 0) {
_collecting = false;
return false; // Nothing to do.
}
// Add final simple edges to graph.
while(delayed_worklist.size() > 0) {
Node* n = delayed_worklist.pop();
add_final_edges(n);
}
int ptnodes_length = ptnodes_worklist.length();
#ifdef ASSERT
if (VerifyConnectionGraph) {
// Verify that no new simple edges could be created and all
// local vars has edges.
_verify = true;
for (int next = 0; next < ptnodes_length; ++next) {
PointsToNode* ptn = ptnodes_worklist.at(next);
add_final_edges(ptn->ideal_node());
if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
ptn->dump();
assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
}
}
_verify = false;
}
#endif
// 2. Finish Graph construction by propagating references to all
// java objects through graph.
if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
java_objects_worklist, oop_fields_worklist)) {
// All objects escaped or hit time or iterations limits.
_collecting = false;
return false;
}
// 3. Adjust scalar_replaceable state of nonescaping objects and push
// scalar replaceable allocations on alloc_worklist for processing
// in split_unique_types().
int non_escaped_length = non_escaped_worklist.length();
for (int next = 0; next < non_escaped_length; next++) {
JavaObjectNode* ptn = non_escaped_worklist.at(next);
bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
Node* n = ptn->ideal_node();
if (n->is_Allocate()) {
n->as_Allocate()->_is_non_escaping = noescape;
}
if (n->is_CallStaticJava()) {
n->as_CallStaticJava()->_is_non_escaping = noescape;
}
if (noescape && ptn->scalar_replaceable()) {
adjust_scalar_replaceable_state(ptn);
if (ptn->scalar_replaceable()) {
alloc_worklist.append(ptn->ideal_node());
}
}
}
#ifdef ASSERT
if (VerifyConnectionGraph) {
// Verify that graph is complete - no new edges could be added or needed.
verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
java_objects_worklist, addp_worklist);
}
assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
assert(null_obj->escape_state() == PointsToNode::NoEscape &&
null_obj->edge_count() == 0 &&
!null_obj->arraycopy_src() &&
!null_obj->arraycopy_dst(), "sanity");
#endif
_collecting = false;
} // TracePhase t3("connectionGraph")
// 4. Optimize ideal graph based on EA information.
bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
if (has_non_escaping_obj) {
optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
}
#ifndef PRODUCT
if (PrintEscapeAnalysis) {
dump(ptnodes_worklist); // Dump ConnectionGraph
}
#endif
bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
#ifdef ASSERT
if (VerifyConnectionGraph) {
int alloc_length = alloc_worklist.length();
for (int next = 0; next < alloc_length; ++next) {
Node* n = alloc_worklist.at(next);
PointsToNode* ptn = ptnode_adr(n->_idx);
assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
}
}
#endif
// 5. Separate memory graph for scalar replaceable allcations.
if (has_scalar_replaceable_candidates &&
C->AliasLevel() >= 3 && EliminateAllocations) {
// Now use the escape information to create unique types for
// scalar replaceable objects.
split_unique_types(alloc_worklist);
if (C->failing()) return false;
C->print_method(PHASE_AFTER_EA, 2);
#ifdef ASSERT
} else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
tty->print("=== No allocations eliminated for ");
C->method()->print_short_name();
if(!EliminateAllocations) {
tty->print(" since EliminateAllocations is off ===");
} else if(!has_scalar_replaceable_candidates) {
tty->print(" since there are no scalar replaceable candidates ===");
} else if(C->AliasLevel() < 3) {
tty->print(" since AliasLevel < 3 ===");
}
tty->cr();
#endif
}
return has_non_escaping_obj;
}
// Utility function for nodes that load an object
void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
// Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
// ThreadLocal has RawPtr type.
const Type* t = _igvn->type(n);
if (t->make_ptr() != NULL) {
Node* adr = n->in(MemNode::Address);
#ifdef ASSERT
if (!adr->is_AddP()) {
assert(_igvn->type(adr)->isa_rawptr(), "sanity");
} else {
assert((ptnode_adr(adr->_idx) == NULL ||
ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
}
#endif
add_local_var_and_edge(n, PointsToNode::NoEscape,
adr, delayed_worklist);
}
}
// Populate Connection Graph with PointsTo nodes and create simple
// connection graph edges.
void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
assert(!_verify, "this method sould not be called for verification");
PhaseGVN* igvn = _igvn;
uint n_idx = n->_idx;
PointsToNode* n_ptn = ptnode_adr(n_idx);
if (n_ptn != NULL)
return; // No need to redefine PointsTo node during first iteration.
if (n->is_Call()) {
// Arguments to allocation and locking don't escape.
if (n->is_AbstractLock()) {
// Put Lock and Unlock nodes on IGVN worklist to process them during
// first IGVN optimization when escape information is still available.
record_for_optimizer(n);
} else if (n->is_Allocate()) {
add_call_node(n->as_Call());
record_for_optimizer(n);
} else {
if (n->is_CallStaticJava()) {
const char* name = n->as_CallStaticJava()->_name;
if (name != NULL && strcmp(name, "uncommon_trap") == 0)
return; // Skip uncommon traps
}
// Don't mark as processed since call's arguments have to be processed.
delayed_worklist->push(n);
// Check if a call returns an object.
if ((n->as_Call()->returns_pointer() &&
n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
(n->is_CallStaticJava() &&
n->as_CallStaticJava()->is_boxing_method())) {
add_call_node(n->as_Call());
}
}
return;
}
// Put this check here to process call arguments since some call nodes
// point to phantom_obj.
if (n_ptn == phantom_obj || n_ptn == null_obj)
return; // Skip predefined nodes.
int opcode = n->Opcode();
switch (opcode) {
case Op_AddP: {
Node* base = get_addp_base(n);
PointsToNode* ptn_base = ptnode_adr(base->_idx);
// Field nodes are created for all field types. They are used in
// adjust_scalar_replaceable_state() and split_unique_types().
// Note, non-oop fields will have only base edges in Connection
// Graph because such fields are not used for oop loads and stores.
int offset = address_offset(n, igvn);
add_field(n, PointsToNode::NoEscape, offset);
if (ptn_base == NULL) {
delayed_worklist->push(n); // Process it later.
} else {
n_ptn = ptnode_adr(n_idx);
add_base(n_ptn->as_Field(), ptn_base);
}
break;
}
case Op_CastX2P: {
map_ideal_node(n, phantom_obj);
break;
}
case Op_CastPP:
case Op_CheckCastPP:
case Op_EncodeP:
case Op_DecodeN:
case Op_EncodePKlass:
case Op_DecodeNKlass: {
add_local_var_and_edge(n, PointsToNode::NoEscape,
n->in(1), delayed_worklist);
break;
}
case Op_CMoveP: {
add_local_var(n, PointsToNode::NoEscape);
// Do not add edges during first iteration because some could be
// not defined yet.
delayed_worklist->push(n);
break;
}
case Op_ConP:
case Op_ConN:
case Op_ConNKlass: {
// assume all oop constants globally escape except for null
PointsToNode::EscapeState es;
const Type* t = igvn->type(n);
if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
es = PointsToNode::NoEscape;
} else {
es = PointsToNode::GlobalEscape;
}
add_java_object(n, es);
break;
}
case Op_CreateEx: {
// assume that all exception objects globally escape
add_java_object(n, PointsToNode::GlobalEscape);
break;
}
case Op_LoadKlass:
case Op_LoadNKlass: {
// Unknown class is loaded
map_ideal_node(n, phantom_obj);
break;
}
case Op_LoadP:
case Op_LoadN:
case Op_LoadPLocked: {
add_objload_to_connection_graph(n, delayed_worklist);
break;
}
case Op_Parm: {
map_ideal_node(n, phantom_obj);
break;
}
case Op_PartialSubtypeCheck: {
// Produces Null or notNull and is used in only in CmpP so
// phantom_obj could be used.
map_ideal_node(n, phantom_obj); // Result is unknown
break;
}
case Op_Phi: {
// Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
// ThreadLocal has RawPtr type.
const Type* t = n->as_Phi()->type();
if (t->make_ptr() != NULL) {
add_local_var(n, PointsToNode::NoEscape);
// Do not add edges during first iteration because some could be
// not defined yet.
delayed_worklist->push(n);
}
break;
}
case Op_Proj: {
// we are only interested in the oop result projection from a call
if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
n->in(0)->as_Call()->returns_pointer()) {
add_local_var_and_edge(n, PointsToNode::NoEscape,
n->in(0), delayed_worklist);
}
break;
}
case Op_Rethrow: // Exception object escapes
case Op_Return: {
if (n->req() > TypeFunc::Parms &&
igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
// Treat Return value as LocalVar with GlobalEscape escape state.
add_local_var_and_edge(n, PointsToNode::GlobalEscape,
n->in(TypeFunc::Parms), delayed_worklist);
}
break;
}
case Op_GetAndSetP:
case Op_GetAndSetN: {
add_objload_to_connection_graph(n, delayed_worklist);
// fallthrough
}
case Op_StoreP:
case Op_StoreN:
case Op_StoreNKlass:
case Op_StorePConditional:
case Op_CompareAndSwapP:
case Op_CompareAndSwapN: {
Node* adr = n->in(MemNode::Address);
const Type *adr_type = igvn->type(adr);
adr_type = adr_type->make_ptr();
if (adr_type == NULL) {
break; // skip dead nodes
}
if (adr_type->isa_oopptr() ||
(opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
(adr_type == TypeRawPtr::NOTNULL &&
adr->in(AddPNode::Address)->is_Proj() &&
adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
delayed_worklist->push(n); // Process it later.
#ifdef ASSERT
assert(adr->is_AddP(), "expecting an AddP");
if (adr_type == TypeRawPtr::NOTNULL) {
// Verify a raw address for a store captured by Initialize node.
int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
assert(offs != Type::OffsetBot, "offset must be a constant");
}
#endif
} else {
// Ignore copy the displaced header to the BoxNode (OSR compilation).
if (adr->is_BoxLock())
break;
// Stored value escapes in unsafe access.
if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
// Pointer stores in G1 barriers looks like unsafe access.
// Ignore such stores to be able scalar replace non-escaping
// allocations.
if (UseG1GC && adr->is_AddP()) {
Node* base = get_addp_base(adr);
if (base->Opcode() == Op_LoadP &&
base->in(MemNode::Address)->is_AddP()) {
adr = base->in(MemNode::Address);
Node* tls = get_addp_base(adr);
if (tls->Opcode() == Op_ThreadLocal) {
int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
PtrQueue::byte_offset_of_buf())) {
break; // G1 pre barier previous oop value store.
}
if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
PtrQueue::byte_offset_of_buf())) {
break; // G1 post barier card address store.
}
}
}
}
delayed_worklist->push(n); // Process unsafe access later.
break;
}
#ifdef ASSERT
n->dump(1);
assert(false, "not unsafe or G1 barrier raw StoreP");
#endif
}
break;
}
case Op_AryEq:
case Op_StrComp:
case Op_StrEquals:
case Op_StrIndexOf:
case Op_EncodeISOArray: {
add_local_var(n, PointsToNode::ArgEscape);
delayed_worklist->push(n); // Process it later.
break;
}
case Op_ThreadLocal: {
add_java_object(n, PointsToNode::ArgEscape);
break;
}
default:
; // Do nothing for nodes not related to EA.
}
return;
}
#ifdef ASSERT
#define ELSE_FAIL(name) \
/* Should not be called for not pointer type. */ \
n->dump(1); \
assert(false, name); \
break;
#else
#define ELSE_FAIL(name) \
break;
#endif
// Add final simple edges to graph.
void ConnectionGraph::add_final_edges(Node *n) {
PointsToNode* n_ptn = ptnode_adr(n->_idx);
#ifdef ASSERT
if (_verify && n_ptn->is_JavaObject())
return; // This method does not change graph for JavaObject.
#endif
if (n->is_Call()) {
process_call_arguments(n->as_Call());
return;
}
assert(n->is_Store() || n->is_LoadStore() ||
(n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
"node should be registered already");
int opcode = n->Opcode();
switch (opcode) {
case Op_AddP: {
Node* base = get_addp_base(n);
PointsToNode* ptn_base = ptnode_adr(base->_idx);
assert(ptn_base != NULL, "field's base should be registered");
add_base(n_ptn->as_Field(), ptn_base);
break;
}
case Op_CastPP:
case Op_CheckCastPP:
case Op_EncodeP:
case Op_DecodeN:
case Op_EncodePKlass:
case Op_DecodeNKlass: {
add_local_var_and_edge(n, PointsToNode::NoEscape,
n->in(1), NULL);
break;
}
case Op_CMoveP: {
for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
Node* in = n->in(i);
if (in == NULL)
continue; // ignore NULL
Node* uncast_in = in->uncast();
if (uncast_in->is_top() || uncast_in == n)
continue; // ignore top or inputs which go back this node
PointsToNode* ptn = ptnode_adr(in->_idx);
assert(ptn != NULL, "node should be registered");
add_edge(n_ptn, ptn);
}
break;
}
case Op_LoadP:
case Op_LoadN:
case Op_LoadPLocked: {
// Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
// ThreadLocal has RawPtr type.
const Type* t = _igvn->type(n);
if (t->make_ptr() != NULL) {
Node* adr = n->in(MemNode::Address);
add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
break;
}
ELSE_FAIL("Op_LoadP");
}
case Op_Phi: {
// Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
// ThreadLocal has RawPtr type.
const Type* t = n->as_Phi()->type();
if (t->make_ptr() != NULL) {
for (uint i = 1; i < n->req(); i++) {
Node* in = n->in(i);
if (in == NULL)
continue; // ignore NULL
Node* uncast_in = in->uncast();
if (uncast_in->is_top() || uncast_in == n)
continue; // ignore top or inputs which go back this node
PointsToNode* ptn = ptnode_adr(in->_idx);
assert(ptn != NULL, "node should be registered");
add_edge(n_ptn, ptn);
}
break;
}
ELSE_FAIL("Op_Phi");
}
case Op_Proj: {
// we are only interested in the oop result projection from a call
if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
n->in(0)->as_Call()->returns_pointer()) {
add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
break;
}
ELSE_FAIL("Op_Proj");
}
case Op_Rethrow: // Exception object escapes
case Op_Return: {
if (n->req() > TypeFunc::Parms &&
_igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
// Treat Return value as LocalVar with GlobalEscape escape state.
add_local_var_and_edge(n, PointsToNode::GlobalEscape,
n->in(TypeFunc::Parms), NULL);
break;
}
ELSE_FAIL("Op_Return");
}
case Op_StoreP:
case Op_StoreN:
case Op_StoreNKlass:
case Op_StorePConditional:
case Op_CompareAndSwapP:
case Op_CompareAndSwapN:
case Op_GetAndSetP:
case Op_GetAndSetN: {
Node* adr = n->in(MemNode::Address);
const Type *adr_type = _igvn->type(adr);
adr_type = adr_type->make_ptr();
#ifdef ASSERT
if (adr_type == NULL) {
n->dump(1);
assert(adr_type != NULL, "dead node should not be on list");
break;
}
#endif
if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
}
if (adr_type->isa_oopptr() ||
(opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
(adr_type == TypeRawPtr::NOTNULL &&
adr->in(AddPNode::Address)->is_Proj() &&
adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
// Point Address to Value
PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
assert(adr_ptn != NULL &&
adr_ptn->as_Field()->is_oop(), "node should be registered");
Node *val = n->in(MemNode::ValueIn);
PointsToNode* ptn = ptnode_adr(val->_idx);
assert(ptn != NULL, "node should be registered");
add_edge(adr_ptn, ptn);
break;
} else if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
// Stored value escapes in unsafe access.
Node *val = n->in(MemNode::ValueIn);
PointsToNode* ptn = ptnode_adr(val->_idx);
assert(ptn != NULL, "node should be registered");
ptn->set_escape_state(PointsToNode::GlobalEscape);
// Add edge to object for unsafe access with offset.
PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
assert(adr_ptn != NULL, "node should be registered");
if (adr_ptn->is_Field()) {
assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
add_edge(adr_ptn, ptn);
}
break;
}
ELSE_FAIL("Op_StoreP");
}
case Op_AryEq:
case Op_StrComp:
case Op_StrEquals:
case Op_StrIndexOf:
case Op_EncodeISOArray: {
// char[] arrays passed to string intrinsic do not escape but
// they are not scalar replaceable. Adjust escape state for them.
// Start from in(2) edge since in(1) is memory edge.
for (uint i = 2; i < n->req(); i++) {
Node* adr = n->in(i);
const Type* at = _igvn->type(adr);
if (!adr->is_top() && at->isa_ptr()) {
assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
at->isa_ptr() != NULL, "expecting a pointer");
if (adr->is_AddP()) {
adr = get_addp_base(adr);
}
PointsToNode* ptn = ptnode_adr(adr->_idx);
assert(ptn != NULL, "node should be registered");
add_edge(n_ptn, ptn);
}
}
break;
}
default: {
// This method should be called only for EA specific nodes which may
// miss some edges when they were created.
#ifdef ASSERT
n->dump(1);
#endif
guarantee(false, "unknown node");
}
}
return;
}
void ConnectionGraph::add_call_node(CallNode* call) {
assert(call->returns_pointer(), "only for call which returns pointer");
uint call_idx = call->_idx;
if (call->is_Allocate()) {
Node* k = call->in(AllocateNode::KlassNode);
const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
assert(kt != NULL, "TypeKlassPtr required.");
ciKlass* cik = kt->klass();
PointsToNode::EscapeState es = PointsToNode::NoEscape;
bool scalar_replaceable = true;
if (call->is_AllocateArray()) {
if (!cik->is_array_klass()) { // StressReflectiveCode
es = PointsToNode::GlobalEscape;
} else {
int length = call->in(AllocateNode::ALength)->find_int_con(-1);
if (length < 0 || length > EliminateAllocationArraySizeLimit) {
// Not scalar replaceable if the length is not constant or too big.
scalar_replaceable = false;
}
}
} else { // Allocate instance
if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
cik->is_subclass_of(_compile->env()->Reference_klass()) ||
!cik->is_instance_klass() || // StressReflectiveCode
cik->as_instance_klass()->has_finalizer()) {
es = PointsToNode::GlobalEscape;
}
}
add_java_object(call, es);
PointsToNode* ptn = ptnode_adr(call_idx);
if (!scalar_replaceable && ptn->scalar_replaceable()) {
ptn->set_scalar_replaceable(false);
}
} else if (call->is_CallStaticJava()) {
// Call nodes could be different types:
//
// 1. CallDynamicJavaNode (what happened during call is unknown):
//
// - mapped to GlobalEscape JavaObject node if oop is returned;
//
// - all oop arguments are escaping globally;
//
// 2. CallStaticJavaNode (execute bytecode analysis if possible):
//
// - the same as CallDynamicJavaNode if can't do bytecode analysis;
//
// - mapped to GlobalEscape JavaObject node if unknown oop is returned;
// - mapped to NoEscape JavaObject node if non-escaping object allocated
// during call is returned;
// - mapped to ArgEscape LocalVar node pointed to object arguments
// which are returned and does not escape during call;
//
// - oop arguments escaping status is defined by bytecode analysis;
//
// For a static call, we know exactly what method is being called.
// Use bytecode estimator to record whether the call's return value escapes.
ciMethod* meth = call->as_CallJava()->method();
if (meth == NULL) {
const char* name = call->as_CallStaticJava()->_name;
assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
// Returns a newly allocated unescaped object.
add_java_object(call, PointsToNode::NoEscape);
ptnode_adr(call_idx)->set_scalar_replaceable(false);
} else if (meth->is_boxing_method()) {
// Returns boxing object
PointsToNode::EscapeState es;
vmIntrinsics::ID intr = meth->intrinsic_id();
if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
// It does not escape if object is always allocated.
es = PointsToNode::NoEscape;
} else {
// It escapes globally if object could be loaded from cache.
es = PointsToNode::GlobalEscape;
}
add_java_object(call, es);
} else {
BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
call_analyzer->copy_dependencies(_compile->dependencies());
if (call_analyzer->is_return_allocated()) {
// Returns a newly allocated unescaped object, simply
// update dependency information.
// Mark it as NoEscape so that objects referenced by
// it's fields will be marked as NoEscape at least.
add_java_object(call, PointsToNode::NoEscape);
ptnode_adr(call_idx)->set_scalar_replaceable(false);
} else {
// Determine whether any arguments are returned.
const TypeTuple* d = call->tf()->domain();
bool ret_arg = false;
for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
if (d->field_at(i)->isa_ptr() != NULL &&
call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
ret_arg = true;
break;
}
}
if (ret_arg) {
add_local_var(call, PointsToNode::ArgEscape);
} else {
// Returns unknown object.
map_ideal_node(call, phantom_obj);
}
}
}
} else {
// An other type of call, assume the worst case:
// returned value is unknown and globally escapes.
assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
map_ideal_node(call, phantom_obj);
}
}
void ConnectionGraph::process_call_arguments(CallNode *call) {
bool is_arraycopy = false;
switch (call->Opcode()) {
#ifdef ASSERT
case Op_Allocate:
case Op_AllocateArray:
case Op_Lock:
case Op_Unlock:
assert(false, "should be done already");
break;
#endif
case Op_CallLeafNoFP:
is_arraycopy = (call->as_CallLeaf()->_name != NULL &&
strstr(call->as_CallLeaf()->_name, "arraycopy") != 0);
// fall through
case Op_CallLeaf: {
// Stub calls, objects do not escape but they are not scale replaceable.
// Adjust escape state for outgoing arguments.
const TypeTuple * d = call->tf()->domain();
bool src_has_oops = false;
for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
const Type* at = d->field_at(i);
Node *arg = call->in(i);
const Type *aat = _igvn->type(arg);
if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
continue;
if (arg->is_AddP()) {
//
// The inline_native_clone() case when the arraycopy stub is called
// after the allocation before Initialize and CheckCastPP nodes.
// Or normal arraycopy for object arrays case.
//
// Set AddP's base (Allocate) as not scalar replaceable since
// pointer to the base (with offset) is passed as argument.
//
arg = get_addp_base(arg);
}
PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
assert(arg_ptn != NULL, "should be registered");
PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
aat->isa_ptr() != NULL, "expecting an Ptr");
bool arg_has_oops = aat->isa_oopptr() &&
(aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
(aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
if (i == TypeFunc::Parms) {
src_has_oops = arg_has_oops;
}
//
// src or dst could be j.l.Object when other is basic type array:
//
// arraycopy(char[],0,Object*,0,size);
// arraycopy(Object*,0,char[],0,size);
//
// Don't add edges in such cases.
//
bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
arg_has_oops && (i > TypeFunc::Parms);
#ifdef ASSERT
if (!(is_arraycopy ||
(call->as_CallLeaf()->_name != NULL &&
(strcmp(call->as_CallLeaf()->_name, "g1_wb_pre") == 0 ||
strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0)
))) {
call->dump();
fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
}
#endif
// Always process arraycopy's destination object since
// we need to add all possible edges to references in
// source object.
if (arg_esc >= PointsToNode::ArgEscape &&
!arg_is_arraycopy_dest) {
continue;
}
set_escape_state(arg_ptn, PointsToNode::ArgEscape);
if (arg_is_arraycopy_dest) {
Node* src = call->in(TypeFunc::Parms);
if (src->is_AddP()) {
src = get_addp_base(src);
}
PointsToNode* src_ptn = ptnode_adr(src->_idx);
assert(src_ptn != NULL, "should be registered");
if (arg_ptn != src_ptn) {
// Special arraycopy edge:
// A destination object's field can't have the source object
// as base since objects escape states are not related.
// Only escape state of destination object's fields affects
// escape state of fields in source object.
add_arraycopy(call, PointsToNode::ArgEscape, src_ptn, arg_ptn);
}
}
}
}
break;
}
case Op_CallStaticJava: {
// For a static call, we know exactly what method is being called.
// Use bytecode estimator to record the call's escape affects
#ifdef ASSERT
const char* name = call->as_CallStaticJava()->_name;
assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
#endif
ciMethod* meth = call->as_CallJava()->method();
if ((meth != NULL) && meth->is_boxing_method()) {
break; // Boxing methods do not modify any oops.
}
BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
// fall-through if not a Java method or no analyzer information
if (call_analyzer != NULL) {
PointsToNode* call_ptn = ptnode_adr(call->_idx);
const TypeTuple* d = call->tf()->domain();
for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
const Type* at = d->field_at(i);
int k = i - TypeFunc::Parms;
Node* arg = call->in(i);
PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
if (at->isa_ptr() != NULL &&
call_analyzer->is_arg_returned(k)) {
// The call returns arguments.
if (call_ptn != NULL) { // Is call's result used?
assert(call_ptn->is_LocalVar(), "node should be registered");
assert(arg_ptn != NULL, "node should be registered");
add_edge(call_ptn, arg_ptn);
}
}
if (at->isa_oopptr() != NULL &&
arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
if (!call_analyzer->is_arg_stack(k)) {
// The argument global escapes
set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
} else {
set_escape_state(arg_ptn, PointsToNode::ArgEscape);
if (!call_analyzer->is_arg_local(k)) {
// The argument itself doesn't escape, but any fields might
set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
}
}
}
}
if (call_ptn != NULL && call_ptn->is_LocalVar()) {
// The call returns arguments.
assert(call_ptn->edge_count() > 0, "sanity");
if (!call_analyzer->is_return_local()) {
// Returns also unknown object.
add_edge(call_ptn, phantom_obj);
}
}
break;
}
}
default: {
// Fall-through here if not a Java method or no analyzer information
// or some other type of call, assume the worst case: all arguments
// globally escape.
const TypeTuple* d = call->tf()->domain();
for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
const Type* at = d->field_at(i);
if (at->isa_oopptr() != NULL) {
Node* arg = call->in(i);
if (arg->is_AddP()) {
arg = get_addp_base(arg);
}
assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
}
}
}
}
}
// Finish Graph construction.
bool ConnectionGraph::complete_connection_graph(
GrowableArray<PointsToNode*>& ptnodes_worklist,
GrowableArray<JavaObjectNode*>& non_escaped_worklist,
GrowableArray<JavaObjectNode*>& java_objects_worklist,
GrowableArray<FieldNode*>& oop_fields_worklist) {
// Normally only 1-3 passes needed to build Connection Graph depending
// on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
// Set limit to 20 to catch situation when something did go wrong and
// bailout Escape Analysis.
// Also limit build time to 30 sec (60 in debug VM).
#define CG_BUILD_ITER_LIMIT 20
#ifdef ASSERT
#define CG_BUILD_TIME_LIMIT 60.0
#else
#define CG_BUILD_TIME_LIMIT 30.0
#endif
// Propagate GlobalEscape and ArgEscape escape states and check that
// we still have non-escaping objects. The method pushs on _worklist
// Field nodes which reference phantom_object.
if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
return false; // Nothing to do.
}
// Now propagate references to all JavaObject nodes.
int java_objects_length = java_objects_worklist.length();
elapsedTimer time;
int new_edges = 1;
int iterations = 0;
do {
while ((new_edges > 0) &&
(iterations++ < CG_BUILD_ITER_LIMIT) &&
(time.seconds() < CG_BUILD_TIME_LIMIT)) {
time.start();
new_edges = 0;
// Propagate references to phantom_object for nodes pushed on _worklist
// by find_non_escaped_objects() and find_field_value().
new_edges += add_java_object_edges(phantom_obj, false);
for (int next = 0; next < java_objects_length; ++next) {
JavaObjectNode* ptn = java_objects_worklist.at(next);
new_edges += add_java_object_edges(ptn, true);
}
if (new_edges > 0) {
// Update escape states on each iteration if graph was updated.
if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
return false; // Nothing to do.
}
}
time.stop();
}
if ((iterations < CG_BUILD_ITER_LIMIT) &&
(time.seconds() < CG_BUILD_TIME_LIMIT)) {
time.start();
// Find fields which have unknown value.
int fields_length = oop_fields_worklist.length();
for (int next = 0; next < fields_length; next++) {
FieldNode* field = oop_fields_worklist.at(next);
if (field->edge_count() == 0) {
new_edges += find_field_value(field);
// This code may added new edges to phantom_object.
// Need an other cycle to propagate references to phantom_object.
}
}
time.stop();
} else {
new_edges = 0; // Bailout
}
} while (new_edges > 0);
// Bailout if passed limits.
if ((iterations >= CG_BUILD_ITER_LIMIT) ||
(time.seconds() >= CG_BUILD_TIME_LIMIT)) {
Compile* C = _compile;
if (C->log() != NULL) {
C->log()->begin_elem("connectionGraph_bailout reason='reached ");
C->log()->text("%s", (iterations >= CG_BUILD_ITER_LIMIT) ? "iterations" : "time");
C->log()->end_elem(" limit'");
}
assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
// Possible infinite build_connection_graph loop,
// bailout (no changes to ideal graph were made).
return false;
}
#ifdef ASSERT
if (Verbose && PrintEscapeAnalysis) {
tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
iterations, nodes_size(), ptnodes_worklist.length());
}
#endif
#undef CG_BUILD_ITER_LIMIT
#undef CG_BUILD_TIME_LIMIT
// Find fields initialized by NULL for non-escaping Allocations.
int non_escaped_length = non_escaped_worklist.length();
for (int next = 0; next < non_escaped_length; next++) {
JavaObjectNode* ptn = non_escaped_worklist.at(next);
PointsToNode::EscapeState es = ptn->escape_state();
assert(es <= PointsToNode::ArgEscape, "sanity");
if (es == PointsToNode::NoEscape) {
if (find_init_values(ptn, null_obj, _igvn) > 0) {
// Adding references to NULL object does not change escape states
// since it does not escape. Also no fields are added to NULL object.
add_java_object_edges(null_obj, false);
}
}
Node* n = ptn->ideal_node();
if (n->is_Allocate()) {
// The object allocated by this Allocate node will never be
// seen by an other thread. Mark it so that when it is
// expanded no MemBarStoreStore is added.
InitializeNode* ini = n->as_Allocate()->initialization();
if (ini != NULL)
ini->set_does_not_escape();
}
}
return true; // Finished graph construction.
}
// Propagate GlobalEscape and ArgEscape escape states to all nodes
// and check that we still have non-escaping java objects.
bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
GrowableArray<PointsToNode*> escape_worklist;
// First, put all nodes with GlobalEscape and ArgEscape states on worklist.
int ptnodes_length = ptnodes_worklist.length();
for (int next = 0; next < ptnodes_length; ++next) {
PointsToNode* ptn = ptnodes_worklist.at(next);
if (ptn->escape_state() >= PointsToNode::ArgEscape ||
ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
escape_worklist.push(ptn);
}
}
// Set escape states to referenced nodes (edges list).
while (escape_worklist.length() > 0) {
PointsToNode* ptn = escape_worklist.pop();
PointsToNode::EscapeState es = ptn->escape_state();
PointsToNode::EscapeState field_es = ptn->fields_escape_state();
if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
es >= PointsToNode::ArgEscape) {
// GlobalEscape or ArgEscape state of field means it has unknown value.
if (add_edge(ptn, phantom_obj)) {
// New edge was added
add_field_uses_to_worklist(ptn->as_Field());
}
}
for (EdgeIterator i(ptn); i.has_next(); i.next()) {
PointsToNode* e = i.get();
if (e->is_Arraycopy()) {
assert(ptn->arraycopy_dst(), "sanity");
// Propagate only fields escape state through arraycopy edge.
if (e->fields_escape_state() < field_es) {
set_fields_escape_state(e, field_es);
escape_worklist.push(e);
}
} else if (es >= field_es) {
// fields_escape_state is also set to 'es' if it is less than 'es'.
if (e->escape_state() < es) {
set_escape_state(e, es);
escape_worklist.push(e);
}
} else {
// Propagate field escape state.
bool es_changed = false;
if (e->fields_escape_state() < field_es) {
set_fields_escape_state(e, field_es);
es_changed = true;
}
if ((e->escape_state() < field_es) &&
e->is_Field() && ptn->is_JavaObject() &&
e->as_Field()->is_oop()) {
// Change escape state of referenced fileds.
set_escape_state(e, field_es);
es_changed = true;;
} else if (e->escape_state() < es) {
set_escape_state(e, es);
es_changed = true;;
}
if (es_changed) {
escape_worklist.push(e);
}
}
}
}
// Remove escaped objects from non_escaped list.
for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
JavaObjectNode* ptn = non_escaped_worklist.at(next);
if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
non_escaped_worklist.delete_at(next);
}
if (ptn->escape_state() == PointsToNode::NoEscape) {
// Find fields in non-escaped allocations which have unknown value.
find_init_values(ptn, phantom_obj, NULL);
}
}
return (non_escaped_worklist.length() > 0);
}
// Add all references to JavaObject node by walking over all uses.
int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
int new_edges = 0;
if (populate_worklist) {
// Populate _worklist by uses of jobj's uses.
for (UseIterator i(jobj); i.has_next(); i.next()) {
PointsToNode* use = i.get();
if (use->is_Arraycopy())
continue;
add_uses_to_worklist(use);
if (use->is_Field() && use->as_Field()->is_oop()) {
// Put on worklist all field's uses (loads) and
// related field nodes (same base and offset).
add_field_uses_to_worklist(use->as_Field());
}
}
}
while(_worklist.length() > 0) {
PointsToNode* use = _worklist.pop();
if (PointsToNode::is_base_use(use)) {
// Add reference from jobj to field and from field to jobj (field's base).
use = PointsToNode::get_use_node(use)->as_Field();
if (add_base(use->as_Field(), jobj)) {
new_edges++;
}
continue;
}
assert(!use->is_JavaObject(), "sanity");
if (use->is_Arraycopy()) {
if (jobj == null_obj) // NULL object does not have field edges
continue;
// Added edge from Arraycopy node to arraycopy's source java object
if (add_edge(use, jobj)) {
jobj->set_arraycopy_src();
new_edges++;
}
// and stop here.
continue;
}
if (!add_edge(use, jobj))
continue; // No new edge added, there was such edge already.
new_edges++;
if (use->is_LocalVar()) {
add_uses_to_worklist(use);
if (use->arraycopy_dst()) {
for (EdgeIterator i(use); i.has_next(); i.next()) {
PointsToNode* e = i.get();
if (e->is_Arraycopy()) {
if (jobj == null_obj) // NULL object does not have field edges
continue;
// Add edge from arraycopy's destination java object to Arraycopy node.
if (add_edge(jobj, e)) {
new_edges++;
jobj->set_arraycopy_dst();
}
}
}
}
} else {
// Added new edge to stored in field values.
// Put on worklist all field's uses (loads) and
// related field nodes (same base and offset).
add_field_uses_to_worklist(use->as_Field());
}
}
return new_edges;
}
// Put on worklist all related field nodes.
void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
assert(field->is_oop(), "sanity");
int offset = field->offset();
add_uses_to_worklist(field);
// Loop over all bases of this field and push on worklist Field nodes
// with the same offset and base (since they may reference the same field).
for (BaseIterator i(field); i.has_next(); i.next()) {
PointsToNode* base = i.get();
add_fields_to_worklist(field, base);
// Check if the base was source object of arraycopy and go over arraycopy's
// destination objects since values stored to a field of source object are
// accessable by uses (loads) of fields of destination objects.
if (base->arraycopy_src()) {
for (UseIterator j(base); j.has_next(); j.next()) {
PointsToNode* arycp = j.get();
if (arycp->is_Arraycopy()) {
for (UseIterator k(arycp); k.has_next(); k.next()) {
PointsToNode* abase = k.get();
if (abase->arraycopy_dst() && abase != base) {
// Look for the same arracopy reference.
add_fields_to_worklist(field, abase);
}
}
}
}
}
}
}
// Put on worklist all related field nodes.
void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
int offset = field->offset();
if (base->is_LocalVar()) {
for (UseIterator j(base); j.has_next(); j.next()) {
PointsToNode* f = j.get();
if (PointsToNode::is_base_use(f)) { // Field
f = PointsToNode::get_use_node(f);
if (f == field || !f->as_Field()->is_oop())
continue;
int offs = f->as_Field()->offset();
if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
add_to_worklist(f);
}
}
}
} else {
assert(base->is_JavaObject(), "sanity");
if (// Skip phantom_object since it is only used to indicate that
// this field's content globally escapes.
(base != phantom_obj) &&
// NULL object node does not have fields.
(base != null_obj)) {
for (EdgeIterator i(base); i.has_next(); i.next()) {
PointsToNode* f = i.get();
// Skip arraycopy edge since store to destination object field
// does not update value in source object field.
if (f->is_Arraycopy()) {
assert(base->arraycopy_dst(), "sanity");
continue;
}
if (f == field || !f->as_Field()->is_oop())
continue;
int offs = f->as_Field()->offset();
if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
add_to_worklist(f);
}
}
}
}
}
// Find fields which have unknown value.
int ConnectionGraph::find_field_value(FieldNode* field) {
// Escaped fields should have init value already.
assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
int new_edges = 0;
for (BaseIterator i(field); i.has_next(); i.next()) {
PointsToNode* base = i.get();
if (base->is_JavaObject()) {
// Skip Allocate's fields which will be processed later.
if (base->ideal_node()->is_Allocate())
return 0;
assert(base == null_obj, "only NULL ptr base expected here");
}
}
if (add_edge(field, phantom_obj)) {
// New edge was added
new_edges++;
add_field_uses_to_worklist(field);
}
return new_edges;
}
// Find fields initializing values for allocations.
int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
int new_edges = 0;
Node* alloc = pta->ideal_node();
if (init_val == phantom_obj) {
// Do nothing for Allocate nodes since its fields values are "known".
if (alloc->is_Allocate())
return 0;
assert(alloc->as_CallStaticJava(), "sanity");
#ifdef ASSERT
if (alloc->as_CallStaticJava()->method() == NULL) {
const char* name = alloc->as_CallStaticJava()->_name;
assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
}
#endif
// Non-escaped allocation returned from Java or runtime call have
// unknown values in fields.
for (EdgeIterator i(pta); i.has_next(); i.next()) {
PointsToNode* field = i.get();
if (field->is_Field() && field->as_Field()->is_oop()) {
if (add_edge(field, phantom_obj)) {
// New edge was added
new_edges++;
add_field_uses_to_worklist(field->as_Field());
}
}
}
return new_edges;
}
assert(init_val == null_obj, "sanity");
// Do nothing for Call nodes since its fields values are unknown.
if (!alloc->is_Allocate())
return 0;
InitializeNode* ini = alloc->as_Allocate()->initialization();
Compile* C = _compile;
bool visited_bottom_offset = false;
GrowableArray<int> offsets_worklist;
// Check if an oop field's initializing value is recorded and add
// a corresponding NULL if field's value if it is not recorded.
// Connection Graph does not record a default initialization by NULL
// captured by Initialize node.
//
for (EdgeIterator i(pta); i.has_next(); i.next()) {
PointsToNode* field = i.get(); // Field (AddP)
if (!field->is_Field() || !field->as_Field()->is_oop())
continue; // Not oop field
int offset = field->as_Field()->offset();
if (offset == Type::OffsetBot) {
if (!visited_bottom_offset) {
// OffsetBot is used to reference array's element,
// always add reference to NULL to all Field nodes since we don't
// known which element is referenced.
if (add_edge(field, null_obj)) {
// New edge was added
new_edges++;
add_field_uses_to_worklist(field->as_Field());
visited_bottom_offset = true;
}
}
} else {
// Check only oop fields.
const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
if (adr_type->isa_rawptr()) {
#ifdef ASSERT
// Raw pointers are used for initializing stores so skip it
// since it should be recorded already
Node* base = get_addp_base(field->ideal_node());
assert(adr_type->isa_rawptr() && base->is_Proj() &&
(base->in(0) == alloc),"unexpected pointer type");
#endif
continue;
}
if (!offsets_worklist.contains(offset)) {
offsets_worklist.append(offset);
Node* value = NULL;
if (ini != NULL) {
// StoreP::memory_type() == T_ADDRESS
BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
// Make sure initializing store has the same type as this AddP.
// This AddP may reference non existing field because it is on a
// dead branch of bimorphic call which is not eliminated yet.
if (store != NULL && store->is_Store() &&
store->as_Store()->memory_type() == ft) {
value = store->in(MemNode::ValueIn);
#ifdef ASSERT
if (VerifyConnectionGraph) {
// Verify that AddP already points to all objects the value points to.
PointsToNode* val = ptnode_adr(value->_idx);
assert((val != NULL), "should be processed already");
PointsToNode* missed_obj = NULL;
if (val->is_JavaObject()) {
if (!field->points_to(val->as_JavaObject())) {
missed_obj = val;
}
} else {
if (!val->is_LocalVar() || (val->edge_count() == 0)) {
tty->print_cr("----------init store has invalid value -----");
store->dump();
val->dump();
assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
}
for (EdgeIterator j(val); j.has_next(); j.next()) {
PointsToNode* obj = j.get();
if (obj->is_JavaObject()) {
if (!field->points_to(obj->as_JavaObject())) {
missed_obj = obj;
break;
}
}
}
}
if (missed_obj != NULL) {
tty->print_cr("----------field---------------------------------");
field->dump();
tty->print_cr("----------missed referernce to object-----------");
missed_obj->dump();
tty->print_cr("----------object referernced by init store -----");
store->dump();
val->dump();
assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
}
}
#endif
} else {
// There could be initializing stores which follow allocation.
// For example, a volatile field store is not collected
// by Initialize node.
//
// Need to check for dependent loads to separate such stores from
// stores which follow loads. For now, add initial value NULL so
// that compare pointers optimization works correctly.
}
}
if (value == NULL) {
// A field's initializing value was not recorded. Add NULL.
if (add_edge(field, null_obj)) {
// New edge was added
new_edges++;
add_field_uses_to_worklist(field->as_Field());
}
}
}
}
}
return new_edges;
}
// Adjust scalar_replaceable state after Connection Graph is built.
void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
// Search for non-escaping objects which are not scalar replaceable
// and mark them to propagate the state to referenced objects.
// 1. An object is not scalar replaceable if the field into which it is
// stored has unknown offset (stored into unknown element of an array).
//
for (UseIterator i(jobj); i.has_next(); i.next()) {
PointsToNode* use = i.get();
assert(!use->is_Arraycopy(), "sanity");
if (use->is_Field()) {
FieldNode* field = use->as_Field();
assert(field->is_oop() && field->scalar_replaceable() &&
field->fields_escape_state() == PointsToNode::NoEscape, "sanity");
if (field->offset() == Type::OffsetBot) {
jobj->set_scalar_replaceable(false);
return;
}
}
assert(use->is_Field() || use->is_LocalVar(), "sanity");
// 2. An object is not scalar replaceable if it is merged with other objects.
for (EdgeIterator j(use); j.has_next(); j.next()) {
PointsToNode* ptn = j.get();
if (ptn->is_JavaObject() && ptn != jobj) {
// Mark all objects.
jobj->set_scalar_replaceable(false);
ptn->set_scalar_replaceable(false);
}
}
if (!jobj->scalar_replaceable()) {
return;
}
}
for (EdgeIterator j(jobj); j.has_next(); j.next()) {
// Non-escaping object node should point only to field nodes.
FieldNode* field = j.get()->as_Field();
int offset = field->as_Field()->offset();
// 3. An object is not scalar replaceable if it has a field with unknown
// offset (array's element is accessed in loop).
if (offset == Type::OffsetBot) {
jobj->set_scalar_replaceable(false);
return;
}
// 4. Currently an object is not scalar replaceable if a LoadStore node
// access its field since the field value is unknown after it.
//
Node* n = field->ideal_node();
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
if (n->fast_out(i)->is_LoadStore()) {
jobj->set_scalar_replaceable(false);
return;
}
}
// 5. Or the address may point to more then one object. This may produce
// the false positive result (set not scalar replaceable)
// since the flow-insensitive escape analysis can't separate
// the case when stores overwrite the field's value from the case
// when stores happened on different control branches.
//
// Note: it will disable scalar replacement in some cases:
//
// Point p[] = new Point[1];
// p[0] = new Point(); // Will be not scalar replaced
//
// but it will save us from incorrect optimizations in next cases:
//
// Point p[] = new Point[1];
// if ( x ) p[0] = new Point(); // Will be not scalar replaced
//
if (field->base_count() > 1) {
for (BaseIterator i(field); i.has_next(); i.next()) {
PointsToNode* base = i.get();
// Don't take into account LocalVar nodes which
// may point to only one object which should be also
// this field's base by now.
if (base->is_JavaObject() && base != jobj) {
// Mark all bases.
jobj->set_scalar_replaceable(false);
base->set_scalar_replaceable(false);
}
}
}
}
}
#ifdef ASSERT
void ConnectionGraph::verify_connection_graph(
GrowableArray<PointsToNode*>& ptnodes_worklist,
GrowableArray<JavaObjectNode*>& non_escaped_worklist,
GrowableArray<JavaObjectNode*>& java_objects_worklist,
GrowableArray<Node*>& addp_worklist) {
// Verify that graph is complete - no new edges could be added.
int java_objects_length = java_objects_worklist.length();
int non_escaped_length = non_escaped_worklist.length();
int new_edges = 0;
for (int next = 0; next < java_objects_length; ++next) {
JavaObjectNode* ptn = java_objects_worklist.at(next);
new_edges += add_java_object_edges(ptn, true);
}
assert(new_edges == 0, "graph was not complete");
// Verify that escape state is final.
int length = non_escaped_worklist.length();
find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
assert((non_escaped_length == non_escaped_worklist.length()) &&
(non_escaped_length == length) &&
(_worklist.length() == 0), "escape state was not final");
// Verify fields information.
int addp_length = addp_worklist.length();
for (int next = 0; next < addp_length; ++next ) {
Node* n = addp_worklist.at(next);
FieldNode* field = ptnode_adr(n->_idx)->as_Field();
if (field->is_oop()) {
// Verify that field has all bases
Node* base = get_addp_base(n);
PointsToNode* ptn = ptnode_adr(base->_idx);
if (ptn->is_JavaObject()) {
assert(field->has_base(ptn->as_JavaObject()), "sanity");
} else {
assert(ptn->is_LocalVar(), "sanity");
for (EdgeIterator i(ptn); i.has_next(); i.next()) {
PointsToNode* e = i.get();
if (e->is_JavaObject()) {
assert(field->has_base(e->as_JavaObject()), "sanity");
}
}
}
// Verify that all fields have initializing values.
if (field->edge_count() == 0) {
tty->print_cr("----------field does not have references----------");
field->dump();
for (BaseIterator i(field); i.has_next(); i.next()) {
PointsToNode* base = i.get();
tty->print_cr("----------field has next base---------------------");
base->dump();
if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
tty->print_cr("----------base has fields-------------------------");
for (EdgeIterator j(base); j.has_next(); j.next()) {
j.get()->dump();
}
tty->print_cr("----------base has references---------------------");
for (UseIterator j(base); j.has_next(); j.next()) {
j.get()->dump();
}
}
}
for (UseIterator i(field); i.has_next(); i.next()) {
i.get()->dump();
}
assert(field->edge_count() > 0, "sanity");
}
}
}
}
#endif
// Optimize ideal graph.
void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
GrowableArray<Node*>& storestore_worklist) {
Compile* C = _compile;
PhaseIterGVN* igvn = _igvn;
if (EliminateLocks) {
// Mark locks before changing ideal graph.
int cnt = C->macro_count();
for( int i=0; i < cnt; i++ ) {
Node *n = C->macro_node(i);
if (n->is_AbstractLock()) { // Lock and Unlock nodes
AbstractLockNode* alock = n->as_AbstractLock();
if (!alock->is_non_esc_obj()) {
if (not_global_escape(alock->obj_node())) {
assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
// The lock could be marked eliminated by lock coarsening
// code during first IGVN before EA. Replace coarsened flag
// to eliminate all associated locks/unlocks.
alock->set_non_esc_obj();
}
}
}
}
}
if (OptimizePtrCompare) {
// Add ConI(#CC_GT) and ConI(#CC_EQ).
_pcmp_neq = igvn->makecon(TypeInt::CC_GT);
_pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
// Optimize objects compare.
while (ptr_cmp_worklist.length() != 0) {
Node *n = ptr_cmp_worklist.pop();
Node *res = optimize_ptr_compare(n);
if (res != NULL) {
#ifndef PRODUCT
if (PrintOptimizePtrCompare) {
tty->print_cr("++++ Replaced: %d %s(%d,%d) --> %s", n->_idx, (n->Opcode() == Op_CmpP ? "CmpP" : "CmpN"), n->in(1)->_idx, n->in(2)->_idx, (res == _pcmp_eq ? "EQ" : "NotEQ"));
if (Verbose) {
n->dump(1);
}
}
#endif
igvn->replace_node(n, res);
}
}
// cleanup
if (_pcmp_neq->outcnt() == 0)
igvn->hash_delete(_pcmp_neq);
if (_pcmp_eq->outcnt() == 0)
igvn->hash_delete(_pcmp_eq);
}
// For MemBarStoreStore nodes added in library_call.cpp, check
// escape status of associated AllocateNode and optimize out
// MemBarStoreStore node if the allocated object never escapes.
while (storestore_worklist.length() != 0) {
Node *n = storestore_worklist.pop();
MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
if (not_global_escape(alloc)) {
MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
igvn->register_new_node_with_optimizer(mb);
igvn->replace_node(storestore, mb);
}
}
}
// Optimize objects compare.
Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
assert(OptimizePtrCompare, "sanity");
PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
JavaObjectNode* jobj1 = unique_java_object(n->in(1));
JavaObjectNode* jobj2 = unique_java_object(n->in(2));
assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
// Check simple cases first.
if (jobj1 != NULL) {
if (jobj1->escape_state() == PointsToNode::NoEscape) {
if (jobj1 == jobj2) {
// Comparing the same not escaping object.
return _pcmp_eq;
}
Node* obj = jobj1->ideal_node();
// Comparing not escaping allocation.
if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
!ptn2->points_to(jobj1)) {
return _pcmp_neq; // This includes nullness check.
}
}
}
if (jobj2 != NULL) {
if (jobj2->escape_state() == PointsToNode::NoEscape) {
Node* obj = jobj2->ideal_node();
// Comparing not escaping allocation.
if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
!ptn1->points_to(jobj2)) {
return _pcmp_neq; // This includes nullness check.
}
}
}
if (jobj1 != NULL && jobj1 != phantom_obj &&
jobj2 != NULL && jobj2 != phantom_obj &&
jobj1->ideal_node()->is_Con() &&
jobj2->ideal_node()->is_Con()) {
// Klass or String constants compare. Need to be careful with
// compressed pointers - compare types of ConN and ConP instead of nodes.
const Type* t1 = jobj1->ideal_node()->get_ptr_type();
const Type* t2 = jobj2->ideal_node()->get_ptr_type();
if (t1->make_ptr() == t2->make_ptr()) {
return _pcmp_eq;
} else {
return _pcmp_neq;
}
}
if (ptn1->meet(ptn2)) {
return NULL; // Sets are not disjoint
}
// Sets are disjoint.
bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
bool set1_has_null_ptr = ptn1->points_to(null_obj);
bool set2_has_null_ptr = ptn2->points_to(null_obj);
if (set1_has_unknown_ptr && set2_has_null_ptr ||
set2_has_unknown_ptr && set1_has_null_ptr) {
// Check nullness of unknown object.
return NULL;
}
// Disjointness by itself is not sufficient since
// alias analysis is not complete for escaped objects.
// Disjoint sets are definitely unrelated only when
// at least one set has only not escaping allocations.
if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
if (ptn1->non_escaping_allocation()) {
return _pcmp_neq;
}
}
if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
if (ptn2->non_escaping_allocation()) {
return _pcmp_neq;
}
}
return NULL;
}
// Connection Graph constuction functions.
void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
PointsToNode* ptadr = _nodes.at(n->_idx);
if (ptadr != NULL) {
assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
return;
}
Compile* C = _compile;
ptadr = new (C->comp_arena()) LocalVarNode(C, n, es);
_nodes.at_put(n->_idx, ptadr);
}
void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
PointsToNode* ptadr = _nodes.at(n->_idx);
if (ptadr != NULL) {
assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
return;
}
Compile* C = _compile;
ptadr = new (C->comp_arena()) JavaObjectNode(C, n, es);
_nodes.at_put(n->_idx, ptadr);
}
void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
PointsToNode* ptadr = _nodes.at(n->_idx);
if (ptadr != NULL) {
assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
return;
}
bool unsafe = false;
bool is_oop = is_oop_field(n, offset, &unsafe);
if (unsafe) {
es = PointsToNode::GlobalEscape;
}
Compile* C = _compile;
FieldNode* field = new (C->comp_arena()) FieldNode(C, n, es, offset, is_oop);
_nodes.at_put(n->_idx, field);
}
void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
PointsToNode* src, PointsToNode* dst) {
assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
PointsToNode* ptadr = _nodes.at(n->_idx);
if (ptadr != NULL) {
assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
return;
}
Compile* C = _compile;
ptadr = new (C->comp_arena()) ArraycopyNode(C, n, es);
_nodes.at_put(n->_idx, ptadr);
// Add edge from arraycopy node to source object.
(void)add_edge(ptadr, src);
src->set_arraycopy_src();
// Add edge from destination object to arraycopy node.
(void)add_edge(dst, ptadr);
dst->set_arraycopy_dst();
}
bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
const Type* adr_type = n->as_AddP()->bottom_type();
BasicType bt = T_INT;
if (offset == Type::OffsetBot) {
// Check only oop fields.
if (!adr_type->isa_aryptr() ||
(adr_type->isa_aryptr()->klass() == NULL) ||
adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
// OffsetBot is used to reference array's element. Ignore first AddP.
if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
bt = T_OBJECT;
}
}
} else if (offset != oopDesc::klass_offset_in_bytes()) {
if (adr_type->isa_instptr()) {
ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
if (field != NULL) {
bt = field->layout_type();
} else {
// Check for unsafe oop field access
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
int opcode = n->fast_out(i)->Opcode();
if (opcode == Op_StoreP || opcode == Op_LoadP ||
opcode == Op_StoreN || opcode == Op_LoadN) {
bt = T_OBJECT;
(*unsafe) = true;
break;
}
}
}
} else if (adr_type->isa_aryptr()) {
if (offset == arrayOopDesc::length_offset_in_bytes()) {
// Ignore array length load.
} else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
// Ignore first AddP.
} else {
const Type* elemtype = adr_type->isa_aryptr()->elem();
bt = elemtype->array_element_basic_type();
}
} else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
// Allocation initialization, ThreadLocal field access, unsafe access
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
int opcode = n->fast_out(i)->Opcode();
if (opcode == Op_StoreP || opcode == Op_LoadP ||
opcode == Op_StoreN || opcode == Op_LoadN) {
bt = T_OBJECT;
break;
}
}
}
}
return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
}
// Returns unique pointed java object or NULL.
JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
assert(!_collecting, "should not call when contructed graph");
// If the node was created after the escape computation we can't answer.
uint idx = n->_idx;
if (idx >= nodes_size()) {
return NULL;
}
PointsToNode* ptn = ptnode_adr(idx);
if (ptn->is_JavaObject()) {
return ptn->as_JavaObject();
}
assert(ptn->is_LocalVar(), "sanity");
// Check all java objects it points to.
JavaObjectNode* jobj = NULL;
for (EdgeIterator i(ptn); i.has_next(); i.next()) {
PointsToNode* e = i.get();
if (e->is_JavaObject()) {
if (jobj == NULL) {
jobj = e->as_JavaObject();
} else if (jobj != e) {
return NULL;
}
}
}
return jobj;
}
// Return true if this node points only to non-escaping allocations.
bool PointsToNode::non_escaping_allocation() {
if (is_JavaObject()) {
Node* n = ideal_node();
if (n->is_Allocate() || n->is_CallStaticJava()) {
return (escape_state() == PointsToNode::NoEscape);
} else {
return false;
}
}
assert(is_LocalVar(), "sanity");
// Check all java objects it points to.
for (EdgeIterator i(this); i.has_next(); i.next()) {
PointsToNode* e = i.get();
if (e->is_JavaObject()) {
Node* n = e->ideal_node();
if ((e->escape_state() != PointsToNode::NoEscape) ||
!(n->is_Allocate() || n->is_CallStaticJava())) {
return false;
}
}
}
return true;
}
// Return true if we know the node does not escape globally.
bool ConnectionGraph::not_global_escape(Node *n) {
assert(!_collecting, "should not call during graph construction");
// If the node was created after the escape computation we can't answer.
uint idx = n->_idx;
if (idx >= nodes_size()) {
return false;
}
PointsToNode* ptn = ptnode_adr(idx);
PointsToNode::EscapeState es = ptn->escape_state();
// If we have already computed a value, return it.
if (es >= PointsToNode::GlobalEscape)
return false;
if (ptn->is_JavaObject()) {
return true; // (es < PointsToNode::GlobalEscape);
}
assert(ptn->is_LocalVar(), "sanity");
// Check all java objects it points to.
for (EdgeIterator i(ptn); i.has_next(); i.next()) {
if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
return false;
}
return true;
}
// Helper functions
// Return true if this node points to specified node or nodes it points to.
bool PointsToNode::points_to(JavaObjectNode* ptn) const {
if (is_JavaObject()) {
return (this == ptn);
}
assert(is_LocalVar() || is_Field(), "sanity");
for (EdgeIterator i(this); i.has_next(); i.next()) {
if (i.get() == ptn)
return true;
}
return false;
}
// Return true if one node points to an other.
bool PointsToNode::meet(PointsToNode* ptn) {
if (this == ptn) {
return true;
} else if (ptn->is_JavaObject()) {
return this->points_to(ptn->as_JavaObject());
} else if (this->is_JavaObject()) {
return ptn->points_to(this->as_JavaObject());
}
assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
int ptn_count = ptn->edge_count();
for (EdgeIterator i(this); i.has_next(); i.next()) {
PointsToNode* this_e = i.get();
for (int j = 0; j < ptn_count; j++) {
if (this_e == ptn->edge(j))
return true;
}
}
return false;
}
#ifdef ASSERT
// Return true if bases point to this java object.
bool FieldNode::has_base(JavaObjectNode* jobj) const {
for (BaseIterator i(this); i.has_next(); i.next()) {
if (i.get() == jobj)
return true;
}
return false;
}
#endif
int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
const Type *adr_type = phase->type(adr);
if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
adr->in(AddPNode::Address)->is_Proj() &&
adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
// We are computing a raw address for a store captured by an Initialize
// compute an appropriate address type. AddP cases #3 and #5 (see below).
int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
assert(offs != Type::OffsetBot ||
adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
"offset must be a constant or it is initialization of array");
return offs;
}
const TypePtr *t_ptr = adr_type->isa_ptr();
assert(t_ptr != NULL, "must be a pointer type");
return t_ptr->offset();
}
Node* ConnectionGraph::get_addp_base(Node *addp) {
assert(addp->is_AddP(), "must be AddP");
//
// AddP cases for Base and Address inputs:
// case #1. Direct object's field reference:
// Allocate
// |
// Proj #5 ( oop result )
// |
// CheckCastPP (cast to instance type)
// | |
// AddP ( base == address )
//
// case #2. Indirect object's field reference:
// Phi
// |
// CastPP (cast to instance type)
// | |
// AddP ( base == address )
//
// case #3. Raw object's field reference for Initialize node:
// Allocate
// |
// Proj #5 ( oop result )
// top |
// \ |
// AddP ( base == top )
//
// case #4. Array's element reference:
// {CheckCastPP | CastPP}
// | | |
// | AddP ( array's element offset )
// | |
// AddP ( array's offset )
//
// case #5. Raw object's field reference for arraycopy stub call:
// The inline_native_clone() case when the arraycopy stub is called
// after the allocation before Initialize and CheckCastPP nodes.
// Allocate
// |
// Proj #5 ( oop result )
// | |
// AddP ( base == address )
//
// case #6. Constant Pool, ThreadLocal, CastX2P or
// Raw object's field reference:
// {ConP, ThreadLocal, CastX2P, raw Load}
// top |
// \ |
// AddP ( base == top )
//
// case #7. Klass's field reference.
// LoadKlass
// | |
// AddP ( base == address )
//
// case #8. narrow Klass's field reference.
// LoadNKlass
// |
// DecodeN
// | |
// AddP ( base == address )
//
Node *base = addp->in(AddPNode::Base);
if (base->uncast()->is_top()) { // The AddP case #3 and #6.
base = addp->in(AddPNode::Address);
while (base->is_AddP()) {
// Case #6 (unsafe access) may have several chained AddP nodes.
assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
base = base->in(AddPNode::Address);
}
Node* uncast_base = base->uncast();
int opcode = uncast_base->Opcode();
assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
(uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
(uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
}
return base;
}
Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
Node* addp2 = addp->raw_out(0);
if (addp->outcnt() == 1 && addp2->is_AddP() &&
addp2->in(AddPNode::Base) == n &&
addp2->in(AddPNode::Address) == addp) {
assert(addp->in(AddPNode::Base) == n, "expecting the same base");
//
// Find array's offset to push it on worklist first and
// as result process an array's element offset first (pushed second)
// to avoid CastPP for the array's offset.
// Otherwise the inserted CastPP (LocalVar) will point to what
// the AddP (Field) points to. Which would be wrong since
// the algorithm expects the CastPP has the same point as
// as AddP's base CheckCastPP (LocalVar).
//
// ArrayAllocation
// |
// CheckCastPP
// |
// memProj (from ArrayAllocation CheckCastPP)
// | ||
// | || Int (element index)
// | || | ConI (log(element size))
// | || | /
// | || LShift
// | || /
// | AddP (array's element offset)
// | |
// | | ConI (array's offset: #12(32-bits) or #24(64-bits))
// | / /
// AddP (array's offset)
// |
// Load/Store (memory operation on array's element)
//
return addp2;
}
return NULL;
}
//
// Adjust the type and inputs of an AddP which computes the
// address of a field of an instance
//
bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
PhaseGVN* igvn = _igvn;
const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
if (t == NULL) {
// We are computing a raw address for a store captured by an Initialize
// compute an appropriate address type (cases #3 and #5).
assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
assert(offs != Type::OffsetBot, "offset must be a constant");
t = base_t->add_offset(offs)->is_oopptr();
}
int inst_id = base_t->instance_id();
assert(!t->is_known_instance() || t->instance_id() == inst_id,
"old type must be non-instance or match new type");
// The type 't' could be subclass of 'base_t'.
// As result t->offset() could be large then base_t's size and it will
// cause the failure in add_offset() with narrow oops since TypeOopPtr()
// constructor verifies correctness of the offset.
//
// It could happened on subclass's branch (from the type profiling
// inlining) which was not eliminated during parsing since the exactness
// of the allocation type was not propagated to the subclass type check.
//
// Or the type 't' could be not related to 'base_t' at all.
// It could happened when CHA type is different from MDO type on a dead path
// (for example, from instanceof check) which is not collapsed during parsing.
//
// Do nothing for such AddP node and don't process its users since
// this code branch will go away.
//
if (!t->is_known_instance() &&
!base_t->klass()->is_subtype_of(t->klass())) {
return false; // bail out
}
const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
// Do NOT remove the next line: ensure a new alias index is allocated
// for the instance type. Note: C++ will not remove it since the call
// has side effect.
int alias_idx = _compile->get_alias_index(tinst);
igvn->set_type(addp, tinst);
// record the allocation in the node map
set_map(addp, get_map(base->_idx));
// Set addp's Base and Address to 'base'.
Node *abase = addp->in(AddPNode::Base);
Node *adr = addp->in(AddPNode::Address);
if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
adr->in(0)->_idx == (uint)inst_id) {
// Skip AddP cases #3 and #5.
} else {
assert(!abase->is_top(), "sanity"); // AddP case #3
if (abase != base) {
igvn->hash_delete(addp);
addp->set_req(AddPNode::Base, base);
if (abase == adr) {
addp->set_req(AddPNode::Address, base);
} else {
// AddP case #4 (adr is array's element offset AddP node)
#ifdef ASSERT
const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
assert(adr->is_AddP() && atype != NULL &&
atype->instance_id() == inst_id, "array's element offset should be processed first");
#endif
}
igvn->hash_insert(addp);
}
}
// Put on IGVN worklist since at least addp's type was changed above.
record_for_optimizer(addp);
return true;
}
//
// Create a new version of orig_phi if necessary. Returns either the newly
// created phi or an existing phi. Sets create_new to indicate whether a new
// phi was created. Cache the last newly created phi in the node map.
//
PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, bool &new_created) {
Compile *C = _compile;
PhaseGVN* igvn = _igvn;
new_created = false;
int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
// nothing to do if orig_phi is bottom memory or matches alias_idx
if (phi_alias_idx == alias_idx) {
return orig_phi;
}
// Have we recently created a Phi for this alias index?
PhiNode *result = get_map_phi(orig_phi->_idx);
if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
return result;
}
// Previous check may fail when the same wide memory Phi was split into Phis
// for different memory slices. Search all Phis for this region.
if (result != NULL) {
Node* region = orig_phi->in(0);
for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
Node* phi = region->fast_out(i);
if (phi->is_Phi() &&
C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
return phi->as_Phi();
}
}
}
if ((int) (C->live_nodes() + 2*NodeLimitFudgeFactor) > MaxNodeLimit) {
if (C->do_escape_analysis() == true && !C->failing()) {
// Retry compilation without escape analysis.
// If this is the first failure, the sentinel string will "stick"
// to the Compile object, and the C2Compiler will see it and retry.
C->record_failure(C2Compiler::retry_no_escape_analysis());
}
return NULL;
}
orig_phi_worklist.append_if_missing(orig_phi);
const TypePtr *atype = C->get_adr_type(alias_idx);
result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
C->copy_node_notes_to(result, orig_phi);
igvn->set_type(result, result->bottom_type());
record_for_optimizer(result);
set_map(orig_phi, result);
new_created = true;
return result;
}
//
// Return a new version of Memory Phi "orig_phi" with the inputs having the
// specified alias index.
//
PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist) {
assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
Compile *C = _compile;
PhaseGVN* igvn = _igvn;
bool new_phi_created;
PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
if (!new_phi_created) {
return result;
}
GrowableArray<PhiNode *> phi_list;
GrowableArray<uint> cur_input;
PhiNode *phi = orig_phi;
uint idx = 1;
bool finished = false;
while(!finished) {
while (idx < phi->req()) {
Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
if (mem != NULL && mem->is_Phi()) {
PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
if (new_phi_created) {
// found an phi for which we created a new split, push current one on worklist and begin
// processing new one
phi_list.push(phi);
cur_input.push(idx);
phi = mem->as_Phi();
result = newphi;
idx = 1;
continue;
} else {
mem = newphi;
}
}
if (C->failing()) {
return NULL;
}
result->set_req(idx++, mem);
}
#ifdef ASSERT
// verify that the new Phi has an input for each input of the original
assert( phi->req() == result->req(), "must have same number of inputs.");
assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
#endif
// Check if all new phi's inputs have specified alias index.
// Otherwise use old phi.
for (uint i = 1; i < phi->req(); i++) {
Node* in = result->in(i);
assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
}
// we have finished processing a Phi, see if there are any more to do
finished = (phi_list.length() == 0 );
if (!finished) {
phi = phi_list.pop();
idx = cur_input.pop();
PhiNode *prev_result = get_map_phi(phi->_idx);
prev_result->set_req(idx++, result);
result = prev_result;
}
}
return result;
}
//
// The next methods are derived from methods in MemNode.
//
Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
Node *mem = mmem;
// TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
// means an array I have not precisely typed yet. Do not do any
// alias stuff with it any time soon.
if (toop->base() != Type::AnyPtr &&
!(toop->klass() != NULL &&
toop->klass()->is_java_lang_Object() &&
toop->offset() == Type::OffsetBot)) {
mem = mmem->memory_at(alias_idx);
// Update input if it is progress over what we have now
}
return mem;
}
//
// Move memory users to their memory slices.
//
void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *> &orig_phis) {
Compile* C = _compile;
PhaseGVN* igvn = _igvn;
const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
assert(tp != NULL, "ptr type");
int alias_idx = C->get_alias_index(tp);
int general_idx = C->get_general_index(alias_idx);
// Move users first
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node* use = n->fast_out(i);
if (use->is_MergeMem()) {
MergeMemNode* mmem = use->as_MergeMem();
assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
continue; // Nothing to do
}
// Replace previous general reference to mem node.
uint orig_uniq = C->unique();
Node* m = find_inst_mem(n, general_idx, orig_phis);
assert(orig_uniq == C->unique(), "no new nodes");
mmem->set_memory_at(general_idx, m);
--imax;
--i;
} else if (use->is_MemBar()) {
assert(!use->is_Initialize(), "initializing stores should not be moved");
if (use->req() > MemBarNode::Precedent &&
use->in(MemBarNode::Precedent) == n) {
// Don't move related membars.
record_for_optimizer(use);
continue;
}
tp = use->as_MemBar()->adr_type()->isa_ptr();
if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
alias_idx == general_idx) {
continue; // Nothing to do
}
// Move to general memory slice.
uint orig_uniq = C->unique();
Node* m = find_inst_mem(n, general_idx, orig_phis);
assert(orig_uniq == C->unique(), "no new nodes");
igvn->hash_delete(use);
imax -= use->replace_edge(n, m);
igvn->hash_insert(use);
record_for_optimizer(use);
--i;
#ifdef ASSERT
} else if (use->is_Mem()) {
if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
// Don't move related cardmark.
continue;
}
// Memory nodes should have new memory input.
tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
assert(tp != NULL, "ptr type");
int idx = C->get_alias_index(tp);
assert(get_map(use->_idx) != NULL || idx == alias_idx,
"Following memory nodes should have new memory input or be on the same memory slice");
} else if (use->is_Phi()) {
// Phi nodes should be split and moved already.
tp = use->as_Phi()->adr_type()->isa_ptr();
assert(tp != NULL, "ptr type");
int idx = C->get_alias_index(tp);
assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
} else {
use->dump();
assert(false, "should not be here");
#endif
}
}
}
//
// Search memory chain of "mem" to find a MemNode whose address
// is the specified alias index.
//
Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *> &orig_phis) {
if (orig_mem == NULL)
return orig_mem;
Compile* C = _compile;
PhaseGVN* igvn = _igvn;
const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
bool is_instance = (toop != NULL) && toop->is_known_instance();
Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
Node *prev = NULL;
Node *result = orig_mem;
while (prev != result) {
prev = result;
if (result == start_mem)
break; // hit one of our sentinels
if (result->is_Mem()) {
const Type *at = igvn->type(result->in(MemNode::Address));
if (at == Type::TOP)
break; // Dead
assert (at->isa_ptr() != NULL, "pointer type required.");
int idx = C->get_alias_index(at->is_ptr());
if (idx == alias_idx)
break; // Found
if (!is_instance && (at->isa_oopptr() == NULL ||
!at->is_oopptr()->is_known_instance())) {
break; // Do not skip store to general memory slice.
}
result = result->in(MemNode::Memory);
}
if (!is_instance)
continue; // don't search further for non-instance types
// skip over a call which does not affect this memory slice
if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
Node *proj_in = result->in(0);
if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
break; // hit one of our sentinels
} else if (proj_in->is_Call()) {
CallNode *call = proj_in->as_Call();
if (!call->may_modify(toop, igvn)) {
result = call->in(TypeFunc::Memory);
}
} else if (proj_in->is_Initialize()) {
AllocateNode* alloc = proj_in->as_Initialize()->allocation();
// Stop if this is the initialization for the object instance which
// which contains this memory slice, otherwise skip over it.
if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
result = proj_in->in(TypeFunc::Memory);
}
} else if (proj_in->is_MemBar()) {
result = proj_in->in(TypeFunc::Memory);
}
} else if (result->is_MergeMem()) {
MergeMemNode *mmem = result->as_MergeMem();
result = step_through_mergemem(mmem, alias_idx, toop);
if (result == mmem->base_memory()) {
// Didn't find instance memory, search through general slice recursively.
result = mmem->memory_at(C->get_general_index(alias_idx));
result = find_inst_mem(result, alias_idx, orig_phis);
if (C->failing()) {
return NULL;
}
mmem->set_memory_at(alias_idx, result);
}
} else if (result->is_Phi() &&
C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
Node *un = result->as_Phi()->unique_input(igvn);
if (un != NULL) {
orig_phis.append_if_missing(result->as_Phi());
result = un;
} else {
break;
}
} else if (result->is_ClearArray()) {
if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
// Can not bypass initialization of the instance
// we are looking for.
break;
}
// Otherwise skip it (the call updated 'result' value).
} else if (result->Opcode() == Op_SCMemProj) {
Node* mem = result->in(0);
Node* adr = NULL;
if (mem->is_LoadStore()) {
adr = mem->in(MemNode::Address);
} else {
assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
adr = mem->in(3); // Memory edge corresponds to destination array
}
const Type *at = igvn->type(adr);
if (at != Type::TOP) {
assert (at->isa_ptr() != NULL, "pointer type required.");
int idx = C->get_alias_index(at->is_ptr());
assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
break;
}
result = mem->in(MemNode::Memory);
}
}
if (result->is_Phi()) {
PhiNode *mphi = result->as_Phi();
assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
const TypePtr *t = mphi->adr_type();
if (!is_instance) {
// Push all non-instance Phis on the orig_phis worklist to update inputs
// during Phase 4 if needed.
orig_phis.append_if_missing(mphi);
} else if (C->get_alias_index(t) != alias_idx) {
// Create a new Phi with the specified alias index type.
result = split_memory_phi(mphi, alias_idx, orig_phis);
}
}
// the result is either MemNode, PhiNode, InitializeNode.
return result;
}
//
// Convert the types of unescaped object to instance types where possible,
// propagate the new type information through the graph, and update memory
// edges and MergeMem inputs to reflect the new type.
//
// We start with allocations (and calls which may be allocations) on alloc_worklist.
// The processing is done in 4 phases:
//
// Phase 1: Process possible allocations from alloc_worklist. Create instance
// types for the CheckCastPP for allocations where possible.
// Propagate the the new types through users as follows:
// casts and Phi: push users on alloc_worklist
// AddP: cast Base and Address inputs to the instance type
// push any AddP users on alloc_worklist and push any memnode
// users onto memnode_worklist.
// Phase 2: Process MemNode's from memnode_worklist. compute new address type and
// search the Memory chain for a store with the appropriate type
// address type. If a Phi is found, create a new version with
// the appropriate memory slices from each of the Phi inputs.
// For stores, process the users as follows:
// MemNode: push on memnode_worklist
// MergeMem: push on mergemem_worklist
// Phase 3: Process MergeMem nodes from mergemem_worklist. Walk each memory slice
// moving the first node encountered of each instance type to the
// the input corresponding to its alias index.
// appropriate memory slice.
// Phase 4: Update the inputs of non-instance memory Phis and the Memory input of memnodes.
//
// In the following example, the CheckCastPP nodes are the cast of allocation
// results and the allocation of node 29 is unescaped and eligible to be an
// instance type.
//
// We start with:
//
// 7 Parm #memory
// 10 ConI "12"
// 19 CheckCastPP "Foo"
// 20 AddP _ 19 19 10 Foo+12 alias_index=4
// 29 CheckCastPP "Foo"
// 30 AddP _ 29 29 10 Foo+12 alias_index=4
//
// 40 StoreP 25 7 20 ... alias_index=4
// 50 StoreP 35 40 30 ... alias_index=4
// 60 StoreP 45 50 20 ... alias_index=4
// 70 LoadP _ 60 30 ... alias_index=4
// 80 Phi 75 50 60 Memory alias_index=4
// 90 LoadP _ 80 30 ... alias_index=4
// 100 LoadP _ 80 20 ... alias_index=4
//
//
// Phase 1 creates an instance type for node 29 assigning it an instance id of 24
// and creating a new alias index for node 30. This gives:
//
// 7 Parm #memory
// 10 ConI "12"
// 19 CheckCastPP "Foo"
// 20 AddP _ 19 19 10 Foo+12 alias_index=4
// 29 CheckCastPP "Foo" iid=24
// 30 AddP _ 29 29 10 Foo+12 alias_index=6 iid=24
//
// 40 StoreP 25 7 20 ... alias_index=4
// 50 StoreP 35 40 30 ... alias_index=6
// 60 StoreP 45 50 20 ... alias_index=4
// 70 LoadP _ 60 30 ... alias_index=6
// 80 Phi 75 50 60 Memory alias_index=4
// 90 LoadP _ 80 30 ... alias_index=6
// 100 LoadP _ 80 20 ... alias_index=4
//
// In phase 2, new memory inputs are computed for the loads and stores,
// And a new version of the phi is created. In phase 4, the inputs to
// node 80 are updated and then the memory nodes are updated with the
// values computed in phase 2. This results in:
//
// 7 Parm #memory
// 10 ConI "12"
// 19 CheckCastPP "Foo"
// 20 AddP _ 19 19 10 Foo+12 alias_index=4
// 29 CheckCastPP "Foo" iid=24
// 30 AddP _ 29 29 10 Foo+12 alias_index=6 iid=24
//
// 40 StoreP 25 7 20 ... alias_index=4
// 50 StoreP 35 7 30 ... alias_index=6
// 60 StoreP 45 40 20 ... alias_index=4
// 70 LoadP _ 50 30 ... alias_index=6
// 80 Phi 75 40 60 Memory alias_index=4
// 120 Phi 75 50 50 Memory alias_index=6
// 90 LoadP _ 120 30 ... alias_index=6
// 100 LoadP _ 80 20 ... alias_index=4
//
void ConnectionGraph::split_unique_types(GrowableArray<Node *> &alloc_worklist) {
GrowableArray<Node *> memnode_worklist;
GrowableArray<PhiNode *> orig_phis;
PhaseIterGVN *igvn = _igvn;
uint new_index_start = (uint) _compile->num_alias_types();
Arena* arena = Thread::current()->resource_area();
VectorSet visited(arena);
ideal_nodes.clear(); // Reset for use with set_map/get_map.
uint unique_old = _compile->unique();
// Phase 1: Process possible allocations from alloc_worklist.
// Create instance types for the CheckCastPP for allocations where possible.
//
// (Note: don't forget to change the order of the second AddP node on
// the alloc_worklist if the order of the worklist processing is changed,
// see the comment in find_second_addp().)
//
while (alloc_worklist.length() != 0) {
Node *n = alloc_worklist.pop();
uint ni = n->_idx;
if (n->is_Call()) {
CallNode *alloc = n->as_Call();
// copy escape information to call node
PointsToNode* ptn = ptnode_adr(alloc->_idx);
PointsToNode::EscapeState es = ptn->escape_state();
// We have an allocation or call which returns a Java object,
// see if it is unescaped.
if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
continue;
// Find CheckCastPP for the allocate or for the return value of a call
n = alloc->result_cast();
if (n == NULL) { // No uses except Initialize node
if (alloc->is_Allocate()) {
// Set the scalar_replaceable flag for allocation
// so it could be eliminated if it has no uses.
alloc->as_Allocate()->_is_scalar_replaceable = true;
}
if (alloc->is_CallStaticJava()) {
// Set the scalar_replaceable flag for boxing method
// so it could be eliminated if it has no uses.
alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
}
continue;
}
if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
assert(!alloc->is_Allocate(), "allocation should have unique type");
continue;
}
// The inline code for Object.clone() casts the allocation result to
// java.lang.Object and then to the actual type of the allocated
// object. Detect this case and use the second cast.
// Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
// the allocation result is cast to java.lang.Object and then
// to the actual Array type.
if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
&& (alloc->is_AllocateArray() ||
igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
Node *cast2 = NULL;
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node *use = n->fast_out(i);
if (use->is_CheckCastPP()) {
cast2 = use;
break;
}
}
if (cast2 != NULL) {
n = cast2;
} else {
// Non-scalar replaceable if the allocation type is unknown statically
// (reflection allocation), the object can't be restored during
// deoptimization without precise type.
continue;
}
}
if (alloc->is_Allocate()) {
// Set the scalar_replaceable flag for allocation
// so it could be eliminated.
alloc->as_Allocate()->_is_scalar_replaceable = true;
}
if (alloc->is_CallStaticJava()) {
// Set the scalar_replaceable flag for boxing method
// so it could be eliminated.
alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
}
set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
// in order for an object to be scalar-replaceable, it must be:
// - a direct allocation (not a call returning an object)
// - non-escaping
// - eligible to be a unique type
// - not determined to be ineligible by escape analysis
set_map(alloc, n);
set_map(n, alloc);
const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
if (t == NULL)
continue; // not a TypeOopPtr
const TypeOopPtr* tinst = t->cast_to_exactness(true)->is_oopptr()->cast_to_instance_id(ni);
igvn->hash_delete(n);
igvn->set_type(n, tinst);
n->raise_bottom_type(tinst);
igvn->hash_insert(n);
record_for_optimizer(n);
if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
// First, put on the worklist all Field edges from Connection Graph
// which is more accurate then putting immediate users from Ideal Graph.
for (EdgeIterator e(ptn); e.has_next(); e.next()) {
PointsToNode* tgt = e.get();
Node* use = tgt->ideal_node();
assert(tgt->is_Field() && use->is_AddP(),
"only AddP nodes are Field edges in CG");
if (use->outcnt() > 0) { // Don't process dead nodes
Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
if (addp2 != NULL) {
assert(alloc->is_AllocateArray(),"array allocation was expected");
alloc_worklist.append_if_missing(addp2);
}
alloc_worklist.append_if_missing(use);
}
}
// An allocation may have an Initialize which has raw stores. Scan
// the users of the raw allocation result and push AddP users
// on alloc_worklist.
Node *raw_result = alloc->proj_out(TypeFunc::Parms);
assert (raw_result != NULL, "must have an allocation result");
for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
Node *use = raw_result->fast_out(i);
if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
Node* addp2 = find_second_addp(use, raw_result);
if (addp2 != NULL) {
assert(alloc->is_AllocateArray(),"array allocation was expected");
alloc_worklist.append_if_missing(addp2);
}
alloc_worklist.append_if_missing(use);
} else if (use->is_MemBar()) {
memnode_worklist.append_if_missing(use);
}
}
}
} else if (n->is_AddP()) {
JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
if (jobj == NULL || jobj == phantom_obj) {
#ifdef ASSERT
ptnode_adr(get_addp_base(n)->_idx)->dump();
ptnode_adr(n->_idx)->dump();
assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
#endif
_compile->record_failure(C2Compiler::retry_no_escape_analysis());
return;
}
Node *base = get_map(jobj->idx()); // CheckCastPP node
if (!split_AddP(n, base)) continue; // wrong type from dead path
} else if (n->is_Phi() ||
n->is_CheckCastPP() ||
n->is_EncodeP() ||
n->is_DecodeN() ||
(n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
if (visited.test_set(n->_idx)) {
assert(n->is_Phi(), "loops only through Phi's");
continue; // already processed
}
JavaObjectNode* jobj = unique_java_object(n);
if (jobj == NULL || jobj == phantom_obj) {
#ifdef ASSERT
ptnode_adr(n->_idx)->dump();
assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
#endif
_compile->record_failure(C2Compiler::retry_no_escape_analysis());
return;
} else {
Node *val = get_map(jobj->idx()); // CheckCastPP node
TypeNode *tn = n->as_Type();
const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
assert(tinst != NULL && tinst->is_known_instance() &&
tinst->instance_id() == jobj->idx() , "instance type expected.");
const Type *tn_type = igvn->type(tn);
const TypeOopPtr *tn_t;
if (tn_type->isa_narrowoop()) {
tn_t = tn_type->make_ptr()->isa_oopptr();
} else {
tn_t = tn_type->isa_oopptr();
}
if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
if (tn_type->isa_narrowoop()) {
tn_type = tinst->make_narrowoop();
} else {
tn_type = tinst;
}
igvn->hash_delete(tn);
igvn->set_type(tn, tn_type);
tn->set_type(tn_type);
igvn->hash_insert(tn);
record_for_optimizer(n);
} else {
assert(tn_type == TypePtr::NULL_PTR ||
tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
"unexpected type");
continue; // Skip dead path with different type
}
}
} else {
debug_only(n->dump();)
assert(false, "EA: unexpected node");
continue;
}
// push allocation's users on appropriate worklist
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node *use = n->fast_out(i);
if(use->is_Mem() && use->in(MemNode::Address) == n) {
// Load/store to instance's field
memnode_worklist.append_if_missing(use);
} else if (use->is_MemBar()) {
if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
memnode_worklist.append_if_missing(use);
}
} else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
Node* addp2 = find_second_addp(use, n);
if (addp2 != NULL) {
alloc_worklist.append_if_missing(addp2);
}
alloc_worklist.append_if_missing(use);
} else if (use->is_Phi() ||
use->is_CheckCastPP() ||
use->is_EncodeNarrowPtr() ||
use->is_DecodeNarrowPtr() ||
(use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
alloc_worklist.append_if_missing(use);
#ifdef ASSERT
} else if (use->is_Mem()) {
assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
} else if (use->is_MergeMem()) {
assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
} else if (use->is_SafePoint()) {
// Look for MergeMem nodes for calls which reference unique allocation
// (through CheckCastPP nodes) even for debug info.
Node* m = use->in(TypeFunc::Memory);
if (m->is_MergeMem()) {
assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
}
} else if (use->Opcode() == Op_EncodeISOArray) {
if (use->in(MemNode::Memory) == n || use->in(3) == n) {
// EncodeISOArray overwrites destination array
memnode_worklist.append_if_missing(use);
}
} else {
uint op = use->Opcode();
if (!(op == Op_CmpP || op == Op_Conv2B ||
op == Op_CastP2X || op == Op_StoreCM ||
op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
op == Op_StrEquals || op == Op_StrIndexOf)) {
n->dump();
use->dump();
assert(false, "EA: missing allocation reference path");
}
#endif
}
}
}
// New alias types were created in split_AddP().
uint new_index_end = (uint) _compile->num_alias_types();
assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
// Phase 2: Process MemNode's from memnode_worklist. compute new address type and
// compute new values for Memory inputs (the Memory inputs are not
// actually updated until phase 4.)
if (memnode_worklist.length() == 0)
return; // nothing to do
while (memnode_worklist.length() != 0) {
Node *n = memnode_worklist.pop();
if (visited.test_set(n->_idx))
continue;
if (n->is_Phi() || n->is_ClearArray()) {
// we don't need to do anything, but the users must be pushed
} else if (n->is_MemBar()) { // Initialize, MemBar nodes
// we don't need to do anything, but the users must be pushed
n = n->as_MemBar()->proj_out(TypeFunc::Memory);
if (n == NULL)
continue;
} else if (n->Opcode() == Op_EncodeISOArray) {
// get the memory projection
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node *use = n->fast_out(i);
if (use->Opcode() == Op_SCMemProj) {
n = use;
break;
}
}
assert(n->Opcode() == Op_SCMemProj, "memory projection required");
} else {
assert(n->is_Mem(), "memory node required.");
Node *addr = n->in(MemNode::Address);
const Type *addr_t = igvn->type(addr);
if (addr_t == Type::TOP)
continue;
assert (addr_t->isa_ptr() != NULL, "pointer type required.");
int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
assert ((uint)alias_idx < new_index_end, "wrong alias index");
Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
if (_compile->failing()) {
return;
}
if (mem != n->in(MemNode::Memory)) {
// We delay the memory edge update since we need old one in
// MergeMem code below when instances memory slices are separated.
set_map(n, mem);
}
if (n->is_Load()) {
continue; // don't push users
} else if (n->is_LoadStore()) {
// get the memory projection
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node *use = n->fast_out(i);
if (use->Opcode() == Op_SCMemProj) {
n = use;
break;
}
}
assert(n->Opcode() == Op_SCMemProj, "memory projection required");
}
}
// push user on appropriate worklist
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node *use = n->fast_out(i);
if (use->is_Phi() || use->is_ClearArray()) {
memnode_worklist.append_if_missing(use);
} else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
continue;
memnode_worklist.append_if_missing(use);
} else if (use->is_MemBar()) {
if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
memnode_worklist.append_if_missing(use);
}
#ifdef ASSERT
} else if(use->is_Mem()) {
assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
} else if (use->is_MergeMem()) {
assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
} else if (use->Opcode() == Op_EncodeISOArray) {
if (use->in(MemNode::Memory) == n || use->in(3) == n) {
// EncodeISOArray overwrites destination array
memnode_worklist.append_if_missing(use);
}
} else {
uint op = use->Opcode();
if (!(op == Op_StoreCM ||
(op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
op == Op_AryEq || op == Op_StrComp ||
op == Op_StrEquals || op == Op_StrIndexOf)) {
n->dump();
use->dump();
assert(false, "EA: missing memory path");
}
#endif
}
}
}
// Phase 3: Process MergeMem nodes from mergemem_worklist.
// Walk each memory slice moving the first node encountered of each
// instance type to the the input corresponding to its alias index.
uint length = _mergemem_worklist.length();
for( uint next = 0; next < length; ++next ) {
MergeMemNode* nmm = _mergemem_worklist.at(next);
assert(!visited.test_set(nmm->_idx), "should not be visited before");
// Note: we don't want to use MergeMemStream here because we only want to
// scan inputs which exist at the start, not ones we add during processing.
// Note 2: MergeMem may already contains instance memory slices added
// during find_inst_mem() call when memory nodes were processed above.
igvn->hash_delete(nmm);
uint nslices = nmm->req();
for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
Node* mem = nmm->in(i);
Node* cur = NULL;
if (mem == NULL || mem->is_top())
continue;
// First, update mergemem by moving memory nodes to corresponding slices
// if their type became more precise since this mergemem was created.
while (mem->is_Mem()) {
const Type *at = igvn->type(mem->in(MemNode::Address));
if (at != Type::TOP) {
assert (at->isa_ptr() != NULL, "pointer type required.");
uint idx = (uint)_compile->get_alias_index(at->is_ptr());
if (idx == i) {
if (cur == NULL)
cur = mem;
} else {
if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
nmm->set_memory_at(idx, mem);
}
}
}
mem = mem->in(MemNode::Memory);
}
nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
// Find any instance of the current type if we haven't encountered
// already a memory slice of the instance along the memory chain.
for (uint ni = new_index_start; ni < new_index_end; ni++) {
if((uint)_compile->get_general_index(ni) == i) {
Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
if (nmm->is_empty_memory(m)) {
Node* result = find_inst_mem(mem, ni, orig_phis);
if (_compile->failing()) {
return;
}
nmm->set_memory_at(ni, result);
}
}
}
}
// Find the rest of instances values
for (uint ni = new_index_start; ni < new_index_end; ni++) {
const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
Node* result = step_through_mergemem(nmm, ni, tinst);
if (result == nmm->base_memory()) {
// Didn't find instance memory, search through general slice recursively.
result = nmm->memory_at(_compile->get_general_index(ni));
result = find_inst_mem(result, ni, orig_phis);
if (_compile->failing()) {
return;
}
nmm->set_memory_at(ni, result);
}
}
igvn->hash_insert(nmm);
record_for_optimizer(nmm);
}
// Phase 4: Update the inputs of non-instance memory Phis and
// the Memory input of memnodes
// First update the inputs of any non-instance Phi's from
// which we split out an instance Phi. Note we don't have
// to recursively process Phi's encounted on the input memory
// chains as is done in split_memory_phi() since they will
// also be processed here.
for (int j = 0; j < orig_phis.length(); j++) {
PhiNode *phi = orig_phis.at(j);
int alias_idx = _compile->get_alias_index(phi->adr_type());
igvn->hash_delete(phi);
for (uint i = 1; i < phi->req(); i++) {
Node *mem = phi->in(i);
Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
if (_compile->failing()) {
return;
}
if (mem != new_mem) {
phi->set_req(i, new_mem);
}
}
igvn->hash_insert(phi);
record_for_optimizer(phi);
}
// Update the memory inputs of MemNodes with the value we computed
// in Phase 2 and move stores memory users to corresponding memory slices.
// Disable memory split verification code until the fix for 6984348.
// Currently it produces false negative results since it does not cover all cases.
#if 0 // ifdef ASSERT
visited.Reset();
Node_Stack old_mems(arena, _compile->unique() >> 2);
#endif
for (uint i = 0; i < ideal_nodes.size(); i++) {
Node* n = ideal_nodes.at(i);
Node* nmem = get_map(n->_idx);
assert(nmem != NULL, "sanity");
if (n->is_Mem()) {
#if 0 // ifdef ASSERT
Node* old_mem = n->in(MemNode::Memory);
if (!visited.test_set(old_mem->_idx)) {
old_mems.push(old_mem, old_mem->outcnt());
}
#endif
assert(n->in(MemNode::Memory) != nmem, "sanity");
if (!n->is_Load()) {
// Move memory users of a store first.
move_inst_mem(n, orig_phis);
}
// Now update memory input
igvn->hash_delete(n);
n->set_req(MemNode::Memory, nmem);
igvn->hash_insert(n);
record_for_optimizer(n);
} else {
assert(n->is_Allocate() || n->is_CheckCastPP() ||
n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
}
}
#if 0 // ifdef ASSERT
// Verify that memory was split correctly
while (old_mems.is_nonempty()) {
Node* old_mem = old_mems.node();
uint old_cnt = old_mems.index();
old_mems.pop();
assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
}
#endif
}
#ifndef PRODUCT
static const char *node_type_names[] = {
"UnknownType",
"JavaObject",
"LocalVar",
"Field",
"Arraycopy"
};
static const char *esc_names[] = {
"UnknownEscape",
"NoEscape",
"ArgEscape",
"GlobalEscape"
};
void PointsToNode::dump(bool print_state) const {
NodeType nt = node_type();
tty->print("%s ", node_type_names[(int) nt]);
if (print_state) {
EscapeState es = escape_state();
EscapeState fields_es = fields_escape_state();
tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
tty->print("NSR ");
}
if (is_Field()) {
FieldNode* f = (FieldNode*)this;
if (f->is_oop())
tty->print("oop ");
if (f->offset() > 0)
tty->print("+%d ", f->offset());
tty->print("(");
for (BaseIterator i(f); i.has_next(); i.next()) {
PointsToNode* b = i.get();
tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
}
tty->print(" )");
}
tty->print("[");
for (EdgeIterator i(this); i.has_next(); i.next()) {
PointsToNode* e = i.get();
tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
}
tty->print(" [");
for (UseIterator i(this); i.has_next(); i.next()) {
PointsToNode* u = i.get();
bool is_base = false;
if (PointsToNode::is_base_use(u)) {
is_base = true;
u = PointsToNode::get_use_node(u)->as_Field();
}
tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
}
tty->print(" ]] ");
if (_node == NULL)
tty->print_cr("<null>");
else
_node->dump();
}
void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
bool first = true;
int ptnodes_length = ptnodes_worklist.length();
for (int i = 0; i < ptnodes_length; i++) {
PointsToNode *ptn = ptnodes_worklist.at(i);
if (ptn == NULL || !ptn->is_JavaObject())
continue;
PointsToNode::EscapeState es = ptn->escape_state();
if ((es != PointsToNode::NoEscape) && !Verbose) {
continue;
}
Node* n = ptn->ideal_node();
if (n->is_Allocate() || (n->is_CallStaticJava() &&
n->as_CallStaticJava()->is_boxing_method())) {
if (first) {
tty->cr();
tty->print("======== Connection graph for ");
_compile->method()->print_short_name();
tty->cr();
first = false;
}
ptn->dump();
// Print all locals and fields which reference this allocation
for (UseIterator j(ptn); j.has_next(); j.next()) {
PointsToNode* use = j.get();
if (use->is_LocalVar()) {
use->dump(Verbose);
} else if (Verbose) {
use->dump();
}
}
tty->cr();
}
}
}
#endif
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