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Commit 20bc88dc authored by bmeurer's avatar bmeurer Committed by Commit bot
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[turbofan] Make field indices explicit for LoadElimination. 

This makes it easier to read and maintain this code.

R=epertoso@chromium.org

Review-Url: https://codereview.chromium.org/2304093002
Cr-Commit-Position: refs/heads/master@{#39127}
parent e809937e
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Showing with 52 additions and 25 deletions
src/compiler/load-elimination.cc
View file @ 20bc88dc
......@@ -505,7 +505,8 @@ Reduction LoadElimination::ReduceCheckMaps(Node* node) {
AbstractState const* state = node_states_.Get(effect);
if (state == nullptr) return NoChange();
int const map_input_count = node->op()->ValueInputCount() - 1;
if (Node* const object_map = state->LookupField(object, 0)) {
if (Node* const object_map =
state->LookupField(object, FieldIndexOf(HeapObject::kMapOffset))) {
for (int i = 0; i < map_input_count; ++i) {
Node* map = NodeProperties::GetValueInput(node, 1 + i);
if (map == object_map) return Replace(effect);
......@@ -513,7 +514,8 @@ Reduction LoadElimination::ReduceCheckMaps(Node* node) {
}
if (map_input_count == 1) {
Node* const map0 = NodeProperties::GetValueInput(node, 1);
state = state->AddField(object, 0, map0, zone());
state = state->AddField(object, FieldIndexOf(HeapObject::kMapOffset), map0,
zone());
}
return UpdateState(node, state);
}
......@@ -525,7 +527,8 @@ Reduction LoadElimination::ReduceEnsureWritableFastElements(Node* node) {
AbstractState const* state = node_states_.Get(effect);
if (state == nullptr) return NoChange();
Node* fixed_array_map = jsgraph()->FixedArrayMapConstant();
if (Node* const elements_map = state->LookupField(elements, 0)) {
if (Node* const elements_map =
state->LookupField(elements, FieldIndexOf(HeapObject::kMapOffset))) {
// Check if the {elements} already have the fixed array map.
if (elements_map == fixed_array_map) {
ReplaceWithValue(node, elements, effect);
......@@ -533,11 +536,14 @@ Reduction LoadElimination::ReduceEnsureWritableFastElements(Node* node) {
}
}
// We know that the resulting elements have the fixed array map.
state = state->AddField(node, 0, fixed_array_map, zone());
state = state->AddField(node, FieldIndexOf(HeapObject::kMapOffset),
fixed_array_map, zone());
// Kill the previous elements on {object}.
state = state->KillField(object, 2, zone());
state =
state->KillField(object, FieldIndexOf(JSObject::kElementsOffset), zone());
// Add the new elements on {object}.
state = state->AddField(object, 2, node, zone());
state = state->AddField(object, FieldIndexOf(JSObject::kElementsOffset), node,
zone());
return UpdateState(node, state);
}
......@@ -550,20 +556,25 @@ Reduction LoadElimination::ReduceMaybeGrowFastElements(Node* node) {
if (flags & GrowFastElementsFlag::kDoubleElements) {
// We know that the resulting elements have the fixed double array map.
Node* fixed_double_array_map = jsgraph()->FixedDoubleArrayMapConstant();
state = state->AddField(node, 0, fixed_double_array_map, zone());
state = state->AddField(node, FieldIndexOf(HeapObject::kMapOffset),
fixed_double_array_map, zone());
} else {
// We know that the resulting elements have the fixed array map.
Node* fixed_array_map = jsgraph()->FixedArrayMapConstant();
state = state->AddField(node, 0, fixed_array_map, zone());
state = state->AddField(node, FieldIndexOf(HeapObject::kMapOffset),
fixed_array_map, zone());
}
if (flags & GrowFastElementsFlag::kArrayObject) {
// Kill the previous Array::length on {object}.
state = state->KillField(object, 3, zone());
state =
state->KillField(object, FieldIndexOf(JSArray::kLengthOffset), zone());
}
// Kill the previous elements on {object}.
state = state->KillField(object, 2, zone());
state =
state->KillField(object, FieldIndexOf(JSObject::kElementsOffset), zone());
// Add the new elements on {object}.
state = state->AddField(object, 2, node, zone());
state = state->AddField(object, FieldIndexOf(JSObject::kElementsOffset), node,
zone());
return UpdateState(node, state);
}
......@@ -574,18 +585,22 @@ Reduction LoadElimination::ReduceTransitionElementsKind(Node* node) {
Node* const effect = NodeProperties::GetEffectInput(node);
AbstractState const* state = node_states_.Get(effect);
if (state == nullptr) return NoChange();
if (Node* const object_map = state->LookupField(object, 0)) {
if (Node* const object_map =
state->LookupField(object, FieldIndexOf(HeapObject::kMapOffset))) {
if (target_map == object_map) {
// The {object} already has the {target_map}, so this TransitionElements
// {node} is fully redundant (independent of what {source_map} is).
return Replace(effect);
}
state = state->KillField(object, 0, zone());
state =
state->KillField(object, FieldIndexOf(HeapObject::kMapOffset), zone());
if (source_map == object_map) {
state = state->AddField(object, 0, target_map, zone());
state = state->AddField(object, FieldIndexOf(HeapObject::kMapOffset),
target_map, zone());
}
} else {
state = state->KillField(object, 0, zone());
state =
state->KillField(object, FieldIndexOf(HeapObject::kMapOffset), zone());
}
ElementsTransition transition = ElementsTransitionOf(node->op());
switch (transition) {
......@@ -593,7 +608,8 @@ Reduction LoadElimination::ReduceTransitionElementsKind(Node* node) {
break;
case ElementsTransition::kSlowTransition:
// Kill the elements as well.
state = state->KillField(object, 2, zone());
state = state->KillField(object, FieldIndexOf(JSObject::kElementsOffset),
zone());
break;
}
return UpdateState(node, state);
......@@ -812,23 +828,28 @@ LoadElimination::AbstractState const* LoadElimination::ComputeLoopState(
switch (current->opcode()) {
case IrOpcode::kEnsureWritableFastElements: {
Node* const object = NodeProperties::GetValueInput(current, 0);
state = state->KillField(object, 2, zone());
state = state->KillField(
object, FieldIndexOf(JSObject::kElementsOffset), zone());
break;
}
case IrOpcode::kMaybeGrowFastElements: {
GrowFastElementsFlags flags =
GrowFastElementsFlagsOf(current->op());
Node* const object = NodeProperties::GetValueInput(current, 0);
state = state->KillField(object, 2, zone());
state = state->KillField(
object, FieldIndexOf(JSObject::kElementsOffset), zone());
if (flags & GrowFastElementsFlag::kArrayObject) {
state = state->KillField(object, 3, zone());
state = state->KillField(
object, FieldIndexOf(JSArray::kLengthOffset), zone());
}
break;
}
case IrOpcode::kTransitionElementsKind: {
Node* const object = NodeProperties::GetValueInput(current, 0);
state = state->KillField(object, 0, zone());
state = state->KillField(object, 2, zone());
state = state->KillField(
object, FieldIndexOf(HeapObject::kMapOffset), zone());
state = state->KillField(
object, FieldIndexOf(JSObject::kElementsOffset), zone());
break;
}
case IrOpcode::kStoreField: {
......@@ -862,6 +883,14 @@ LoadElimination::AbstractState const* LoadElimination::ComputeLoopState(
return state;
}
// static
int LoadElimination::FieldIndexOf(int offset) {
DCHECK_EQ(0, offset % kPointerSize);
int field_index = offset / kPointerSize;
if (field_index >= static_cast<int>(kMaxTrackedFields)) return -1;
return field_index;
}
// static
int LoadElimination::FieldIndexOf(FieldAccess const& access) {
MachineRepresentation rep = access.machine_type.representation();
......@@ -891,10 +920,7 @@ int LoadElimination::FieldIndexOf(FieldAccess const& access) {
break;
}
DCHECK_EQ(kTaggedBase, access.base_is_tagged);
DCHECK_EQ(0, access.offset % kPointerSize);
int field_index = access.offset / kPointerSize;
if (field_index >= static_cast<int>(kMaxTrackedFields)) return -1;
return field_index;
return FieldIndexOf(access.offset);
}
CommonOperatorBuilder* LoadElimination::common() const {
......
src/compiler/load-elimination.h
View file @ 20bc88dc
......@@ -214,6 +214,7 @@ class LoadElimination final : public AdvancedReducer {
AbstractState const* ComputeLoopState(Node* node,
AbstractState const* state) const;
static int FieldIndexOf(int offset);
static int FieldIndexOf(FieldAccess const& access);
CommonOperatorBuilder* common() const;
......
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