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// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/compiler/diamond.h"
#include "src/compiler/js-builtin-reducer.h"
#include "src/compiler/js-graph.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/node-properties.h"
#include "src/types.h"
namespace v8 {
namespace internal {
namespace compiler {
// Helper class to access JSCallFunction nodes that are potential candidates
// for reduction when they have a BuiltinFunctionId associated with them.
class JSCallReduction {
public:
explicit JSCallReduction(Node* node) : node_(node) {}
// Determines whether the node is a JSCallFunction operation that targets a
// constant callee being a well-known builtin with a BuiltinFunctionId.
bool HasBuiltinFunctionId() {
if (node_->opcode() != IrOpcode::kJSCallFunction) return false;
HeapObjectMatcher m(NodeProperties::GetValueInput(node_, 0));
if (!m.HasValue() || !m.Value().handle()->IsJSFunction()) return false;
Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value().handle());
return function->shared()->HasBuiltinFunctionId();
}
// Retrieves the BuiltinFunctionId as described above.
BuiltinFunctionId GetBuiltinFunctionId() {
DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode());
HeapObjectMatcher m(NodeProperties::GetValueInput(node_, 0));
Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value().handle());
return function->shared()->builtin_function_id();
}
// Determines whether the call takes zero inputs.
bool InputsMatchZero() { return GetJSCallArity() == 0; }
// Determines whether the call takes one input of the given type.
bool InputsMatchOne(Type* t1) {
return GetJSCallArity() == 1 &&
NodeProperties::GetBounds(GetJSCallInput(0)).upper->Is(t1);
}
// Determines whether the call takes two inputs of the given types.
bool InputsMatchTwo(Type* t1, Type* t2) {
return GetJSCallArity() == 2 &&
NodeProperties::GetBounds(GetJSCallInput(0)).upper->Is(t1) &&
NodeProperties::GetBounds(GetJSCallInput(1)).upper->Is(t2);
}
// Determines whether the call takes inputs all of the given type.
bool InputsMatchAll(Type* t) {
for (int i = 0; i < GetJSCallArity(); i++) {
if (!NodeProperties::GetBounds(GetJSCallInput(i)).upper->Is(t)) {
return false;
}
}
return true;
}
Node* left() { return GetJSCallInput(0); }
Node* right() { return GetJSCallInput(1); }
int GetJSCallArity() {
DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode());
// Skip first (i.e. callee) and second (i.e. receiver) operand.
return node_->op()->ValueInputCount() - 2;
}
Node* GetJSCallInput(int index) {
DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode());
DCHECK_LT(index, GetJSCallArity());
// Skip first (i.e. callee) and second (i.e. receiver) operand.
return NodeProperties::GetValueInput(node_, index + 2);
}
private:
Node* node_;
};
JSBuiltinReducer::JSBuiltinReducer(Editor* editor, JSGraph* jsgraph)
: AdvancedReducer(editor),
jsgraph_(jsgraph),
simplified_(jsgraph->zone()) {}
// ECMA-262, section 15.8.2.11.
Reduction JSBuiltinReducer::ReduceMathMax(Node* node) {
JSCallReduction r(node);
if (r.InputsMatchZero()) {
// Math.max() -> -Infinity
return Replace(jsgraph()->Constant(-V8_INFINITY));
}
if (r.InputsMatchOne(Type::Number())) {
// Math.max(a:number) -> a
return Replace(r.left());
}
if (r.InputsMatchAll(Type::Integral32())) {
// Math.max(a:int32, b:int32, ...)
Node* value = r.GetJSCallInput(0);
for (int i = 1; i < r.GetJSCallArity(); i++) {
Node* const input = r.GetJSCallInput(i);
value = graph()->NewNode(
common()->Select(kMachNone),
graph()->NewNode(simplified()->NumberLessThan(), input, value), value,
input);
}
return Replace(value);
}
return NoChange();
}
// ES6 draft 08-24-14, section 20.2.2.19.
Reduction JSBuiltinReducer::ReduceMathImul(Node* node) {
JSCallReduction r(node);
if (r.InputsMatchTwo(Type::Integral32(), Type::Integral32())) {
// Math.imul(a:int32, b:int32) -> Int32Mul(a, b)
Node* value = graph()->NewNode(machine()->Int32Mul(), r.left(), r.right());
return Replace(value);
}
return NoChange();
}
// ES6 draft 08-24-14, section 20.2.2.17.
Reduction JSBuiltinReducer::ReduceMathFround(Node* node) {
JSCallReduction r(node);
if (r.InputsMatchOne(Type::Number())) {
// Math.fround(a:number) -> TruncateFloat64ToFloat32(a)
Node* value =
graph()->NewNode(machine()->TruncateFloat64ToFloat32(), r.left());
return Replace(value);
}
return NoChange();
}
Reduction JSBuiltinReducer::Reduce(Node* node) {
Reduction reduction = NoChange();
JSCallReduction r(node);
// Dispatch according to the BuiltinFunctionId if present.
if (!r.HasBuiltinFunctionId()) return NoChange();
switch (r.GetBuiltinFunctionId()) {
case kMathMax:
reduction = ReduceMathMax(node);
break;
case kMathImul:
reduction = ReduceMathImul(node);
break;
case kMathFround:
reduction = ReduceMathFround(node);
break;
default:
break;
}
// Replace builtin call assuming replacement nodes are pure values that don't
// produce an effect. Replaces {node} with {reduction} and relaxes effects.
if (reduction.Changed()) ReplaceWithValue(node, reduction.replacement());
return reduction;
}
Graph* JSBuiltinReducer::graph() const { return jsgraph()->graph(); }
CommonOperatorBuilder* JSBuiltinReducer::common() const {
return jsgraph()->common();
}
MachineOperatorBuilder* JSBuiltinReducer::machine() const {
return jsgraph()->machine();
}
} // namespace compiler
} // namespace internal
} // namespace v8
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