6674600: (Escape Analysis) Optimize memory graph for instance's fields
Summary: EA gives opportunite to do more aggressive memory optimizations.
Reviewed-by: never, jrose
--- a/hotspot/src/share/vm/opto/callnode.cpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/callnode.cpp Thu Mar 20 15:11:44 2008 -0700
@@ -625,8 +625,8 @@
}
//
-// Determine whether the call could modify a memory value of the
-// specified address type
+// Determine whether the call could modify the field of the specified
+// instance at the specified offset.
//
bool CallNode::may_modify(const TypePtr *addr_t, PhaseTransform *phase) {
const TypeOopPtr *adrInst_t = addr_t->isa_oopptr();
@@ -638,9 +638,24 @@
Compile *C = phase->C;
int offset = adrInst_t->offset();
assert(offset >= 0, "should be valid offset");
- assert(addr_t->isa_instptr() || addr_t->isa_aryptr(), "only instances or arrays are expected");
+ ciKlass* adr_k = adrInst_t->klass();
+ assert(adr_k->is_loaded() &&
+ adr_k->is_java_klass() &&
+ !adr_k->is_interface(),
+ "only non-abstract classes are expected");
int base_idx = C->get_alias_index(adrInst_t);
+ int size = BytesPerLong; // If we don't know the size, assume largest.
+ if (adrInst_t->isa_instptr()) {
+ ciField* field = C->alias_type(base_idx)->field();
+ if (field != NULL) {
+ size = field->size_in_bytes();
+ }
+ } else {
+ assert(adrInst_t->isa_aryptr(), "only arrays are expected");
+ size = type2aelembytes(adr_k->as_array_klass()->element_type()->basic_type());
+ }
+
ciMethod * meth = is_CallStaticJava() ? as_CallStaticJava()->method() : NULL;
BCEscapeAnalyzer *bcea = (meth != NULL) ? meth->get_bcea() : NULL;
@@ -656,14 +671,19 @@
if (!arg->is_top() && (t->isa_oopptr() != NULL ||
t->isa_ptr() && at_ptr != NULL)) {
assert(at_ptr != NULL, "expecting an OopPtr");
- // If we have found an argument matching adr_base_t, check if the field
- // at the specified offset is modified. Since we don't know the size,
- // assume 8.
- int at_idx = C->get_alias_index(at_ptr->add_offset(offset)->isa_oopptr());
- if (base_idx == at_idx &&
- (bcea == NULL ||
- bcea->is_arg_modified(i - TypeFunc::Parms, offset, 8))) {
- return true;
+ ciKlass* at_k = at_ptr->klass();
+ if ((adrInst_t->base() == at_ptr->base()) &&
+ at_k->is_loaded() &&
+ at_k->is_java_klass() &&
+ !at_k->is_interface()) {
+ // If we have found an argument matching addr_t, check if the field
+ // at the specified offset is modified.
+ int at_idx = C->get_alias_index(at_ptr->add_offset(offset)->isa_oopptr());
+ if (base_idx == at_idx &&
+ (bcea == NULL ||
+ bcea->is_arg_modified(i - TypeFunc::Parms, offset, size))) {
+ return true;
+ }
}
}
}
--- a/hotspot/src/share/vm/opto/callnode.hpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/callnode.hpp Thu Mar 20 15:11:44 2008 -0700
@@ -419,7 +419,7 @@
uint _first_index; // First input edge index of a SafePoint node where
// states of the scalarized object fields are collected.
uint _n_fields; // Number of non-static fields of the scalarized object.
- DEBUG_ONLY(AllocateNode* _alloc);
+ DEBUG_ONLY(AllocateNode* _alloc;)
public:
SafePointScalarObjectNode(const TypeOopPtr* tp,
#ifdef ASSERT
--- a/hotspot/src/share/vm/opto/cfgnode.cpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/cfgnode.cpp Thu Mar 20 15:11:44 2008 -0700
@@ -704,6 +704,61 @@
return mem;
}
+//------------------------split_out_instance-----------------------------------
+// Split out an instance type from a bottom phi.
+PhiNode* PhiNode::split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const {
+ assert(type() == Type::MEMORY && (adr_type() == TypePtr::BOTTOM ||
+ adr_type() == TypeRawPtr::BOTTOM) , "bottom or raw memory required");
+
+ // Check if an appropriate node already exists.
+ Node *region = in(0);
+ for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
+ Node* use = region->fast_out(k);
+ if( use->is_Phi()) {
+ PhiNode *phi2 = use->as_Phi();
+ if (phi2->type() == Type::MEMORY && phi2->adr_type() == at) {
+ return phi2;
+ }
+ }
+ }
+ Compile *C = igvn->C;
+ Arena *a = Thread::current()->resource_area();
+ Node_Array node_map = new Node_Array(a);
+ Node_Stack stack(a, C->unique() >> 4);
+ PhiNode *nphi = slice_memory(at);
+ igvn->register_new_node_with_optimizer( nphi );
+ node_map.map(_idx, nphi);
+ stack.push((Node *)this, 1);
+ while(!stack.is_empty()) {
+ PhiNode *ophi = stack.node()->as_Phi();
+ uint i = stack.index();
+ assert(i >= 1, "not control edge");
+ stack.pop();
+ nphi = node_map[ophi->_idx]->as_Phi();
+ for (; i < ophi->req(); i++) {
+ Node *in = ophi->in(i);
+ if (in == NULL || igvn->type(in) == Type::TOP)
+ continue;
+ Node *opt = MemNode::optimize_simple_memory_chain(in, at, igvn);
+ PhiNode *optphi = opt->is_Phi() ? opt->as_Phi() : NULL;
+ if (optphi != NULL && optphi->adr_type() == TypePtr::BOTTOM) {
+ opt = node_map[optphi->_idx];
+ if (opt == NULL) {
+ stack.push(ophi, i);
+ nphi = optphi->slice_memory(at);
+ igvn->register_new_node_with_optimizer( nphi );
+ node_map.map(optphi->_idx, nphi);
+ ophi = optphi;
+ i = 0; // will get incremented at top of loop
+ continue;
+ }
+ }
+ nphi->set_req(i, opt);
+ }
+ }
+ return nphi;
+}
+
//------------------------verify_adr_type--------------------------------------
#ifdef ASSERT
void PhiNode::verify_adr_type(VectorSet& visited, const TypePtr* at) const {
@@ -1736,6 +1791,18 @@
return result;
}
}
+ //
+ // Other optimizations on the memory chain
+ //
+ const TypePtr* at = adr_type();
+ for( uint i=1; i<req(); ++i ) {// For all paths in
+ Node *ii = in(i);
+ Node *new_in = MemNode::optimize_memory_chain(ii, at, phase);
+ if (ii != new_in ) {
+ set_req(i, new_in);
+ progress = this;
+ }
+ }
}
return progress; // Return any progress
--- a/hotspot/src/share/vm/opto/cfgnode.hpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/cfgnode.hpp Thu Mar 20 15:11:44 2008 -0700
@@ -148,6 +148,7 @@
static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL );
// create a new phi with narrowed memory type
PhiNode* slice_memory(const TypePtr* adr_type) const;
+ PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const;
// like make(r, x), but does not initialize the in edges to x
static PhiNode* make_blank( Node* r, Node* x );
--- a/hotspot/src/share/vm/opto/graphKit.cpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/graphKit.cpp Thu Mar 20 15:11:44 2008 -0700
@@ -2922,10 +2922,22 @@
const TypeOopPtr* oop_type = tklass->as_instance_type();
// Now generate allocation code
+
+ // With escape analysis, the entire memory state is needed to be able to
+ // eliminate the allocation. If the allocations cannot be eliminated, this
+ // will be optimized to the raw slice when the allocation is expanded.
+ Node *mem;
+ if (C->do_escape_analysis()) {
+ mem = reset_memory();
+ set_all_memory(mem);
+ } else {
+ mem = memory(Compile::AliasIdxRaw);
+ }
+
AllocateNode* alloc
= new (C, AllocateNode::ParmLimit)
AllocateNode(C, AllocateNode::alloc_type(),
- control(), memory(Compile::AliasIdxRaw), i_o(),
+ control(), mem, i_o(),
size, klass_node,
initial_slow_test);
@@ -3056,11 +3068,23 @@
}
// Now generate allocation code
+
+ // With escape analysis, the entire memory state is needed to be able to
+ // eliminate the allocation. If the allocations cannot be eliminated, this
+ // will be optimized to the raw slice when the allocation is expanded.
+ Node *mem;
+ if (C->do_escape_analysis()) {
+ mem = reset_memory();
+ set_all_memory(mem);
+ } else {
+ mem = memory(Compile::AliasIdxRaw);
+ }
+
// Create the AllocateArrayNode and its result projections
AllocateArrayNode* alloc
= new (C, AllocateArrayNode::ParmLimit)
AllocateArrayNode(C, AllocateArrayNode::alloc_type(),
- control(), memory(Compile::AliasIdxRaw), i_o(),
+ control(), mem, i_o(),
size, klass_node,
initial_slow_test,
length);
--- a/hotspot/src/share/vm/opto/memnode.cpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/memnode.cpp Thu Mar 20 15:11:44 2008 -0700
@@ -29,6 +29,8 @@
#include "incls/_precompiled.incl"
#include "incls/_memnode.cpp.incl"
+static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st);
+
//=============================================================================
uint MemNode::size_of() const { return sizeof(*this); }
@@ -87,6 +89,60 @@
#endif
+Node *MemNode::optimize_simple_memory_chain(Node *mchain, const TypePtr *t_adr, PhaseGVN *phase) {
+ const TypeOopPtr *tinst = t_adr->isa_oopptr();
+ if (tinst == NULL || !tinst->is_instance_field())
+ return mchain; // don't try to optimize non-instance types
+ uint instance_id = tinst->instance_id();
+ Node *prev = NULL;
+ Node *result = mchain;
+ while (prev != result) {
+ prev = result;
+ // 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_Call()) {
+ CallNode *call = proj_in->as_Call();
+ if (!call->may_modify(t_adr, phase)) {
+ 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 != 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()) {
+ result = step_through_mergemem(phase, result->as_MergeMem(), t_adr, NULL, tty);
+ }
+ }
+ return result;
+}
+
+Node *MemNode::optimize_memory_chain(Node *mchain, const TypePtr *t_adr, PhaseGVN *phase) {
+ const TypeOopPtr *t_oop = t_adr->isa_oopptr();
+ bool is_instance = (t_oop != NULL) && t_oop->is_instance_field();
+ PhaseIterGVN *igvn = phase->is_IterGVN();
+ Node *result = mchain;
+ result = optimize_simple_memory_chain(result, t_adr, phase);
+ if (is_instance && igvn != NULL && result->is_Phi()) {
+ PhiNode *mphi = result->as_Phi();
+ assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
+ const TypePtr *t = mphi->adr_type();
+ if (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM) {
+ // clone the Phi with our address type
+ result = mphi->split_out_instance(t_adr, igvn);
+ } else {
+ assert(phase->C->get_alias_index(t) == phase->C->get_alias_index(t_adr), "correct memory chain");
+ }
+ }
+ return result;
+}
+
static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st) {
uint alias_idx = phase->C->get_alias_index(tp);
Node *mem = mmem;
@@ -266,6 +322,8 @@
if (offset == Type::OffsetBot)
return NULL; // cannot unalias unless there are precise offsets
+ const TypeOopPtr *addr_t = adr->bottom_type()->isa_oopptr();
+
intptr_t size_in_bytes = memory_size();
Node* mem = in(MemNode::Memory); // start searching here...
@@ -345,6 +403,22 @@
return mem; // let caller handle steps (c), (d)
}
+ } else if (addr_t != NULL && addr_t->is_instance_field()) {
+ // Can't use optimize_simple_memory_chain() since it needs PhaseGVN.
+ if (mem->is_Proj() && mem->in(0)->is_Call()) {
+ CallNode *call = mem->in(0)->as_Call();
+ if (!call->may_modify(addr_t, phase)) {
+ mem = call->in(TypeFunc::Memory);
+ continue; // (a) advance through independent call memory
+ }
+ } else if (mem->is_Proj() && mem->in(0)->is_MemBar()) {
+ mem = mem->in(0)->in(TypeFunc::Memory);
+ continue; // (a) advance through independent MemBar memory
+ } else if (mem->is_MergeMem()) {
+ int alias_idx = phase->C->get_alias_index(adr_type());
+ mem = mem->as_MergeMem()->memory_at(alias_idx);
+ continue; // (a) advance through independent MergeMem memory
+ }
}
// Unless there is an explicit 'continue', we must bail out here,
@@ -1011,6 +1085,122 @@
}
}
+ Node* mem = in(MemNode::Memory);
+ const TypePtr *addr_t = phase->type(address)->isa_ptr();
+
+ if (addr_t != NULL) {
+ // try to optimize our memory input
+ Node* opt_mem = MemNode::optimize_memory_chain(mem, addr_t, phase);
+ if (opt_mem != mem) {
+ set_req(MemNode::Memory, opt_mem);
+ return this;
+ }
+ const TypeOopPtr *t_oop = addr_t->isa_oopptr();
+ if (can_reshape && opt_mem->is_Phi() &&
+ (t_oop != NULL) && t_oop->is_instance_field()) {
+ assert(t_oop->offset() != Type::OffsetBot && t_oop->offset() != Type::OffsetTop, "");
+ Node *region = opt_mem->in(0);
+ uint cnt = opt_mem->req();
+ for( uint i = 1; i < cnt; i++ ) {
+ Node *in = opt_mem->in(i);
+ if( in == NULL ) {
+ region = NULL; // Wait stable graph
+ break;
+ }
+ }
+ if (region != NULL) {
+ // Check for loop invariant.
+ if (cnt == 3) {
+ for( uint i = 1; i < cnt; i++ ) {
+ Node *in = opt_mem->in(i);
+ Node* m = MemNode::optimize_memory_chain(in, addr_t, phase);
+ if (m == opt_mem) {
+ set_req(MemNode::Memory, opt_mem->in(cnt - i)); // Skip this phi.
+ return this;
+ }
+ }
+ }
+ // Split through Phi (see original code in loopopts.cpp).
+ assert(phase->C->have_alias_type(addr_t), "instance should have alias type");
+ const Type* this_type = this->bottom_type();
+ int this_index = phase->C->get_alias_index(addr_t);
+ int this_offset = addr_t->offset();
+ int this_iid = addr_t->is_oopptr()->instance_id();
+ int wins = 0;
+ PhaseIterGVN *igvn = phase->is_IterGVN();
+ Node *phi = new (igvn->C, region->req()) PhiNode(region, this_type, NULL, this_iid, this_index, this_offset);
+ for( uint i = 1; i < region->req(); i++ ) {
+ Node *x;
+ Node* the_clone = NULL;
+ if( region->in(i) == phase->C->top() ) {
+ x = phase->C->top(); // Dead path? Use a dead data op
+ } else {
+ x = this->clone(); // Else clone up the data op
+ the_clone = x; // Remember for possible deletion.
+ // Alter data node to use pre-phi inputs
+ if( this->in(0) == region ) {
+ x->set_req( 0, region->in(i) );
+ } else {
+ x->set_req( 0, NULL );
+ }
+ for( uint j = 1; j < this->req(); j++ ) {
+ Node *in = this->in(j);
+ if( in->is_Phi() && in->in(0) == region )
+ x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone
+ }
+ }
+ // Check for a 'win' on some paths
+ const Type *t = x->Value(igvn);
+
+ bool singleton = t->singleton();
+
+ // See comments in PhaseIdealLoop::split_thru_phi().
+ if( singleton && t == Type::TOP ) {
+ singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
+ }
+
+ if( singleton ) {
+ wins++;
+ x = igvn->makecon(t);
+ } else {
+ // We now call Identity to try to simplify the cloned node.
+ // Note that some Identity methods call phase->type(this).
+ // Make sure that the type array is big enough for
+ // our new node, even though we may throw the node away.
+ // (This tweaking with igvn only works because x is a new node.)
+ igvn->set_type(x, t);
+ Node *y = x->Identity(igvn);
+ if( y != x ) {
+ wins++;
+ x = y;
+ } else {
+ y = igvn->hash_find(x);
+ if( y ) {
+ wins++;
+ x = y;
+ } else {
+ // Else x is a new node we are keeping
+ // We do not need register_new_node_with_optimizer
+ // because set_type has already been called.
+ igvn->_worklist.push(x);
+ }
+ }
+ }
+ if (x != the_clone && the_clone != NULL)
+ igvn->remove_dead_node(the_clone);
+ phi->set_req(i, x);
+ }
+ if( wins > 0 ) {
+ // Record Phi
+ igvn->register_new_node_with_optimizer(phi);
+ return phi;
+ } else {
+ igvn->remove_dead_node(phi);
+ }
+ }
+ }
+ }
+
// Check for prior store with a different base or offset; make Load
// independent. Skip through any number of them. Bail out if the stores
// are in an endless dead cycle and report no progress. This is a key
--- a/hotspot/src/share/vm/opto/memnode.hpp Thu Mar 20 13:51:55 2008 -0700
+++ b/hotspot/src/share/vm/opto/memnode.hpp Thu Mar 20 15:11:44 2008 -0700
@@ -67,6 +67,8 @@
PhaseTransform* phase);
static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);
+ static Node *optimize_simple_memory_chain(Node *mchain, const TypePtr *t_adr, PhaseGVN *phase);
+ static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, PhaseGVN *phase);
// This one should probably be a phase-specific function:
static bool detect_dominating_control(Node* dom, Node* sub);