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[turbofan] Improve deferred code handling for polymorphic property access.

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Only mark the last fallthrough control as deferred, otherwise the
splintering will ruin the code generation for the (maybe likely)
polymorphic cases.

Drive-by-fix: Reduce overall code duplication between JSLoadNamed
and JSStoreNamed specialization.

R=jarin@chromium.org
BUG=v8:4470
LOG=n

Review URL: https://codereview.chromium.org/1424733002

Cr-Commit-Position: refs/heads/master@{#31623}
This commit is contained in:
bmeurer 2015-10-28 04:00:51 -07:00 committed by Commit bot
parent 8da26dd6df
commit 22b9ec0bcd
2 changed files with 127 additions and 240 deletions
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362
src/compiler/js-native-context-specialization.cc
View File

@ -477,10 +477,11 @@ bool JSNativeContextSpecialization::ComputePropertyAccessInfos(
}
Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadNamed, node->opcode());
NamedAccess const& p = NamedAccessOf(node->op());
Handle<Name> name = p.name();
Reduction JSNativeContextSpecialization::ReduceNamedAccess(
Node* node, Node* value, MapHandleList const& receiver_maps,
Handle<Name> name, PropertyAccessMode access_mode) {
DCHECK(node->opcode() == IrOpcode::kJSLoadNamed ||
node->opcode() == IrOpcode::kJSStoreNamed);
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* frame_state = NodeProperties::GetFrameStateInput(node, 1);
Node* effect = NodeProperties::GetEffectInput(node);
@ -489,16 +490,10 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
// Not much we can do if deoptimization support is disabled.
if (!(flags() & kDeoptimizationEnabled)) return NoChange();
// Extract receiver maps from the LOAD_IC using the LoadICNexus.
MapHandleList receiver_maps;
if (!p.feedback().IsValid()) return NoChange();
LoadICNexus nexus(p.feedback().vector(), p.feedback().slot());
if (nexus.ExtractMaps(&receiver_maps) == 0) return NoChange();
DCHECK_LT(0, receiver_maps.length());
// Compute property access infos for the receiver maps.
ZoneVector<PropertyAccessInfo> access_infos(zone());
if (!ComputePropertyAccessInfos(receiver_maps, name, kLoad, &access_infos)) {
if (!ComputePropertyAccessInfos(receiver_maps, name, access_mode,
&access_infos)) {
return NoChange();
}
@ -506,7 +501,7 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
if (access_infos.empty()) return NoChange();
// The final states for every polymorphic branch. We join them with
// Merge+Phi+EffectPhi at the bottom.
// Merge++Phi+EffectPhi at the bottom.
ZoneVector<Node*> values(zone());
ZoneVector<Node*> effects(zone());
ZoneVector<Node*> controls(zone());
@ -532,7 +527,8 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
// Generate code for the various different property access patterns.
Node* fallthrough_control = control;
for (PropertyAccessInfo const& access_info : access_infos) {
Node* this_value = receiver;
Node* this_value = value;
Node* this_receiver = receiver;
Node* this_effect = effect;
Node* this_control;
@ -546,8 +542,8 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
Node* check =
graph()->NewNode(machine()->Uint32LessThan(), receiver_instance_type,
jsgraph()->Uint32Constant(FIRST_NONSTRING_TYPE));
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, fallthrough_control);
Node* branch =
graph()->NewNode(common()->Branch(), check, fallthrough_control);
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
this_control = graph()->NewNode(common()->IfTrue(), branch);
} else {
@ -559,8 +555,8 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(Type::Internal()),
receiver_map, jsgraph()->Constant(map));
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, fallthrough_control);
Node* branch =
graph()->NewNode(common()->Branch(), check, fallthrough_control);
this_controls.push_back(graph()->NewNode(common()->IfTrue(), branch));
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
}
@ -575,44 +571,98 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
if (access_info.holder().ToHandle(&holder)) {
this_value = jsgraph()->Constant(holder);
AssumePrototypesStable(receiver_type, holder);
if (access_mode == kLoad) {
this_receiver = jsgraph()->Constant(holder);
}
}
// Generate the actual property access.
if (access_info.IsDataConstant()) {
this_value = jsgraph()->Constant(access_info.constant());
if (access_mode == kStore) {
Node* check = graph()->NewNode(
simplified()->ReferenceEqual(Type::Tagged()), value, this_value);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
exit_controls.push_back(graph()->NewNode(common()->IfFalse(), branch));
this_control = graph()->NewNode(common()->IfTrue(), branch);
}
} else {
// TODO(bmeurer): This is sort of adhoc, and must be refactored into some
// common code once we also have support for stores.
DCHECK(access_info.IsDataField());
FieldIndex const field_index = access_info.field_index();
Type* const field_type = access_info.field_type();
if (!field_index.is_inobject()) {
this_value = this_effect = graph()->NewNode(
this_receiver = this_effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectProperties()),
this_value, this_effect, this_control);
this_receiver, this_effect, this_control);
}
FieldAccess field_access;
field_access.base_is_tagged = kTaggedBase;
field_access.offset = field_index.offset();
field_access.name = name;
field_access.type = field_type;
field_access.machine_type = kMachAnyTagged;
if (field_type->Is(Type::UntaggedFloat64())) {
if (!field_index.is_inobject() || field_index.is_hidden_field() ||
!FLAG_unbox_double_fields) {
this_value = this_effect =
graph()->NewNode(simplified()->LoadField(field_access),
this_value, this_effect, this_control);
field_access.offset = HeapNumber::kValueOffset;
field_access.name = MaybeHandle<Name>();
FieldAccess field_access = {kTaggedBase, field_index.offset(), name,
field_type, kMachAnyTagged};
if (access_mode == kLoad) {
if (field_type->Is(Type::UntaggedFloat64())) {
if (!field_index.is_inobject() || field_index.is_hidden_field() ||
!FLAG_unbox_double_fields) {
this_receiver = this_effect =
graph()->NewNode(simplified()->LoadField(field_access),
this_receiver, this_effect, this_control);
field_access.offset = HeapNumber::kValueOffset;
field_access.name = MaybeHandle<Name>();
}
field_access.machine_type = kMachFloat64;
}
field_access.machine_type = kMachFloat64;
this_value = this_effect =
graph()->NewNode(simplified()->LoadField(field_access),
this_receiver, this_effect, this_control);
} else {
DCHECK_EQ(kStore, access_mode);
if (field_type->Is(Type::TaggedSigned())) {
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), value);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
exit_controls.push_back(
graph()->NewNode(common()->IfFalse(), branch));
this_control = graph()->NewNode(common()->IfTrue(), branch);
} else if (field_type->Is(Type::TaggedPointer())) {
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), value);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kFalse),
check, this_control);
exit_controls.push_back(graph()->NewNode(common()->IfTrue(), branch));
this_control = graph()->NewNode(common()->IfFalse(), branch);
if (field_type->NumClasses() > 0) {
// Emit a (sequence of) map checks for the value.
ZoneVector<Node*> this_controls(zone());
Node* value_map = this_effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForMap()), value,
this_effect, this_control);
for (auto i = field_type->Classes(); !i.Done(); i.Advance()) {
Handle<Map> field_map(i.Current());
check = graph()->NewNode(
simplified()->ReferenceEqual(Type::Internal()), value_map,
jsgraph()->Constant(field_map));
branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
this_control = graph()->NewNode(common()->IfFalse(), branch);
this_controls.push_back(
graph()->NewNode(common()->IfTrue(), branch));
}
exit_controls.push_back(this_control);
int const this_control_count =
static_cast<int>(this_controls.size());
this_control =
(this_control_count == 1)
? this_controls.front()
: graph()->NewNode(common()->Merge(this_control_count),
this_control_count,
&this_controls.front());
}
} else {
DCHECK(field_type->Is(Type::Tagged()));
}
this_effect = graph()->NewNode(simplified()->StoreField(field_access),
this_receiver, this_value, this_effect,
this_control);
}
this_value = this_effect =
graph()->NewNode(simplified()->LoadField(field_access), this_value,
this_effect, this_control);
}
// Remember the final state for this property access.
@ -622,6 +672,17 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
}
// Collect the fallthru control as final "exit" control.
if (fallthrough_control != control) {
// Mark the last fallthru branch as deferred.
Node* branch = NodeProperties::GetControlInput(fallthrough_control);
DCHECK_EQ(IrOpcode::kBranch, branch->opcode());
if (fallthrough_control->opcode() == IrOpcode::kIfTrue) {
NodeProperties::ChangeOp(branch, common()->Branch(BranchHint::kFalse));
} else {
DCHECK_EQ(IrOpcode::kIfFalse, fallthrough_control->opcode());
NodeProperties::ChangeOp(branch, common()->Branch(BranchHint::kTrue));
}
}
exit_controls.push_back(fallthrough_control);
// Generate the single "exit" point, where we get if either all map/instance
@ -641,7 +702,6 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
NodeProperties::MergeControlToEnd(graph(), common(), deoptimize);
// Generate the final merge point for all (polymorphic) branches.
Node* value;
int const control_count = static_cast<int>(controls.size());
if (control_count == 1) {
value = values.front();
@ -661,18 +721,27 @@ Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
}
Reduction JSNativeContextSpecialization::ReduceJSLoadNamed(Node* node) {
DCHECK_EQ(IrOpcode::kJSLoadNamed, node->opcode());
NamedAccess const& p = NamedAccessOf(node->op());
Node* const value = jsgraph()->Dead();
// Extract receiver maps from the LOAD_IC using the LoadICNexus.
MapHandleList receiver_maps;
if (!p.feedback().IsValid()) return NoChange();
LoadICNexus nexus(p.feedback().vector(), p.feedback().slot());
if (nexus.ExtractMaps(&receiver_maps) == 0) return NoChange();
DCHECK_LT(0, receiver_maps.length());
// Try to lower the named access based on the {receiver_maps}.
return ReduceNamedAccess(node, value, receiver_maps, p.name(), kLoad);
}
Reduction JSNativeContextSpecialization::ReduceJSStoreNamed(Node* node) {
DCHECK_EQ(IrOpcode::kJSStoreNamed, node->opcode());
NamedAccess const& p = NamedAccessOf(node->op());
Handle<Name> name = p.name();
Node* receiver = NodeProperties::GetValueInput(node, 0);
Node* value = NodeProperties::GetValueInput(node, 1);
Node* frame_state = NodeProperties::GetFrameStateInput(node, 1);
Node* effect = NodeProperties::GetEffectInput(node);
Node* control = NodeProperties::GetControlInput(node);
// Not much we can do if deoptimization support is disabled.
if (!(flags() & kDeoptimizationEnabled)) return NoChange();
Node* const value = NodeProperties::GetValueInput(node, 1);
// Extract receiver maps from the STORE_IC using the StoreICNexus.
MapHandleList receiver_maps;
@ -681,195 +750,8 @@ Reduction JSNativeContextSpecialization::ReduceJSStoreNamed(Node* node) {
if (nexus.ExtractMaps(&receiver_maps) == 0) return NoChange();
DCHECK_LT(0, receiver_maps.length());
// Compute property access infos for the receiver maps.
ZoneVector<PropertyAccessInfo> access_infos(zone());
if (!ComputePropertyAccessInfos(receiver_maps, name, kStore, &access_infos)) {
return NoChange();
}
// Nothing to do if we have no non-deprecated maps.
if (access_infos.empty()) return NoChange();
// The final states for every polymorphic branch. We join them with
// Merge+EffectPhi at the bottom.
ZoneVector<Node*> effects(zone());
ZoneVector<Node*> controls(zone());
// The list of "exiting" controls, which currently go to a single deoptimize.
// TODO(bmeurer): Consider using an IC as fallback.
Node* const exit_effect = effect;
ZoneVector<Node*> exit_controls(zone());
// Ensure that {receiver} is a heap object.
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), receiver);
Node* branch =
graph()->NewNode(common()->Branch(BranchHint::kFalse), check, control);
exit_controls.push_back(graph()->NewNode(common()->IfTrue(), branch));
control = graph()->NewNode(common()->IfFalse(), branch);
// Load the {receiver} map. The resulting effect is the dominating effect for
// all (polymorphic) branches.
Node* receiver_map = effect =
graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
receiver, effect, control);
// Generate code for the various different property access patterns.
Node* fallthrough_control = control;
for (PropertyAccessInfo const& access_info : access_infos) {
Node* this_receiver = receiver;
Node* this_effect = effect;
Node* this_control;
// Perform map check on {receiver}.
Type* receiver_type = access_info.receiver_type();
if (receiver_type->Is(Type::String())) {
// Emit an instance type check for strings.
Node* receiver_instance_type = this_effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForMapInstanceType()),
receiver_map, this_effect, fallthrough_control);
Node* check =
graph()->NewNode(machine()->Uint32LessThan(), receiver_instance_type,
jsgraph()->Uint32Constant(FIRST_NONSTRING_TYPE));
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, fallthrough_control);
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
this_control = graph()->NewNode(common()->IfTrue(), branch);
} else {
// Emit a (sequence of) map checks for other properties.
ZoneVector<Node*> this_controls(zone());
for (auto i = access_info.receiver_type()->Classes(); !i.Done();
i.Advance()) {
Handle<Map> map = i.Current();
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(Type::Internal()),
receiver_map, jsgraph()->Constant(map));
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, fallthrough_control);
this_controls.push_back(graph()->NewNode(common()->IfTrue(), branch));
fallthrough_control = graph()->NewNode(common()->IfFalse(), branch);
}
int const this_control_count = static_cast<int>(this_controls.size());
this_control =
(this_control_count == 1)
? this_controls.front()
: graph()->NewNode(common()->Merge(this_control_count),
this_control_count, &this_controls.front());
}
// Determine actual holder and perform prototype chain checks.
Handle<JSObject> holder;
if (access_info.holder().ToHandle(&holder)) {
AssumePrototypesStable(receiver_type, holder);
}
// Generate the actual property access.
if (access_info.IsDataConstant()) {
Node* check =
graph()->NewNode(simplified()->ReferenceEqual(Type::Tagged()), value,
jsgraph()->Constant(access_info.constant()));
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
exit_controls.push_back(graph()->NewNode(common()->IfFalse(), branch));
this_control = graph()->NewNode(common()->IfTrue(), branch);
} else {
// TODO(bmeurer): This is sort of adhoc, and must be refactored into some
// common code once we also have support for stores.
DCHECK(access_info.IsDataField());
FieldIndex const field_index = access_info.field_index();
Type* const field_type = access_info.field_type();
if (!field_index.is_inobject()) {
this_receiver = this_effect = graph()->NewNode(
simplified()->LoadField(AccessBuilder::ForJSObjectProperties()),
this_receiver, this_effect, this_control);
}
FieldAccess field_access;
field_access.base_is_tagged = kTaggedBase;
field_access.offset = field_index.offset();
field_access.name = name;
field_access.type = field_type;
field_access.machine_type = kMachAnyTagged;
if (field_type->Is(Type::TaggedSigned())) {
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), value);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
exit_controls.push_back(graph()->NewNode(common()->IfFalse(), branch));
this_control = graph()->NewNode(common()->IfTrue(), branch);
} else if (field_type->Is(Type::TaggedPointer())) {
Node* check = graph()->NewNode(simplified()->ObjectIsSmi(), value);
Node* branch = graph()->NewNode(common()->Branch(BranchHint::kFalse),
check, this_control);
exit_controls.push_back(graph()->NewNode(common()->IfTrue(), branch));
this_control = graph()->NewNode(common()->IfFalse(), branch);
if (field_type->NumClasses() > 0) {
// Emit a (sequence of) map checks for the value.
ZoneVector<Node*> this_controls(zone());
Node* value_map = this_effect =
graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
value, this_effect, this_control);
for (auto i = field_type->Classes(); !i.Done(); i.Advance()) {
Handle<Map> field_map(i.Current());
check =
graph()->NewNode(simplified()->ReferenceEqual(Type::Internal()),
value_map, jsgraph()->Constant(field_map));
branch = graph()->NewNode(common()->Branch(BranchHint::kTrue),
check, this_control);
this_control = graph()->NewNode(common()->IfFalse(), branch);
this_controls.push_back(
graph()->NewNode(common()->IfTrue(), branch));
}
exit_controls.push_back(this_control);
int const this_control_count = static_cast<int>(this_controls.size());
this_control = (this_control_count == 1)
? this_controls.front()
: graph()->NewNode(
common()->Merge(this_control_count),
this_control_count, &this_controls.front());
}
} else {
DCHECK(field_type->Is(Type::Tagged()));
}
this_effect =
graph()->NewNode(simplified()->StoreField(field_access),
this_receiver, value, this_effect, this_control);
}
// Remember the final state for this property access.
effects.push_back(this_effect);
controls.push_back(this_control);
}
// Collect the fallthru control as final "exit" control.
exit_controls.push_back(fallthrough_control);
// Generate the single "exit" point, where we get if either all map/instance
// type checks failed, or one of the assumptions inside one of the cases
// failes (i.e. failing prototype chain check).
// TODO(bmeurer): Consider falling back to IC here if deoptimization is
// disabled.
int const exit_control_count = static_cast<int>(exit_controls.size());
Node* exit_control =
(exit_control_count == 1)
? exit_controls.front()
: graph()->NewNode(common()->Merge(exit_control_count),
exit_control_count, &exit_controls.front());
Node* deoptimize = graph()->NewNode(common()->Deoptimize(), frame_state,
exit_effect, exit_control);
// TODO(bmeurer): This should be on the AdvancedReducer somehow.
NodeProperties::MergeControlToEnd(graph(), common(), deoptimize);
// Generate the final merge point for all (polymorphic) branches.
int const control_count = static_cast<int>(controls.size());
if (control_count == 1) {
effect = effects.front();
control = controls.front();
} else {
control = graph()->NewNode(common()->Merge(control_count), control_count,
&controls.front());
effects.push_back(control);
effect = graph()->NewNode(common()->EffectPhi(control_count),
control_count + 1, &effects.front());
}
return Replace(node, value, effect, control);
// Try to lower the named access based on the {receiver_maps}.
return ReduceNamedAccess(node, value, receiver_maps, p.name(), kStore);
}

5
src/compiler/js-native-context-specialization.h
View File

@ -68,6 +68,11 @@ class JSNativeContextSpecialization final : public AdvancedReducer {
PropertyAccessMode access_mode,
ZoneVector<PropertyAccessInfo>* access_infos);
Reduction ReduceNamedAccess(Node* node, Node* value,
MapHandleList const& receiver_maps,
Handle<Name> name,
PropertyAccessMode access_mode);
struct ScriptContextTableLookupResult;
bool LookupInScriptContextTable(Handle<Name> name,
ScriptContextTableLookupResult* result);