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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/js-graph.h"
#include "src/compiler/simplified-operator.h"
namespace v8 {
namespace internal {
namespace compiler {
enum IdentifyZeros { kIdentifyZeros, kDistinguishZeros };
class Truncation final {
// Constructors.
static Truncation None() {
return Truncation(TruncationKind::kNone, kIdentifyZeros);
static Truncation Bool() {
return Truncation(TruncationKind::kBool, kIdentifyZeros);
static Truncation Word32() {
return Truncation(TruncationKind::kWord32, kIdentifyZeros);
static Truncation Word64() {
return Truncation(TruncationKind::kWord64, kIdentifyZeros);
static Truncation Float64(IdentifyZeros identify_zeros = kDistinguishZeros) {
return Truncation(TruncationKind::kFloat64, identify_zeros);
static Truncation Any(IdentifyZeros identify_zeros = kDistinguishZeros) {
return Truncation(TruncationKind::kAny, identify_zeros);
static Truncation Generalize(Truncation t1, Truncation t2) {
return Truncation(
Generalize(t1.kind(), t2.kind()),
GeneralizeIdentifyZeros(t1.identify_zeros(), t2.identify_zeros()));
// Queries.
bool IsUnused() const { return kind_ == TruncationKind::kNone; }
bool IsUsedAsBool() const {
return LessGeneral(kind_, TruncationKind::kBool);
bool IsUsedAsWord32() const {
return LessGeneral(kind_, TruncationKind::kWord32);
bool IsUsedAsFloat64() const {
return LessGeneral(kind_, TruncationKind::kFloat64);
bool IdentifiesUndefinedAndZero() {
return LessGeneral(kind_, TruncationKind::kWord32) ||
LessGeneral(kind_, TruncationKind::kBool);
bool IdentifiesUndefinedAndNaN() {
return LessGeneral(kind_, TruncationKind::kFloat64) ||
LessGeneral(kind_, TruncationKind::kWord64);
bool IdentifiesZeroAndMinusZero() const {
return identify_zeros() == kIdentifyZeros;
// Operators.
bool operator==(Truncation other) const {
return kind() == other.kind() && identify_zeros() == other.identify_zeros();
bool operator!=(Truncation other) const { return !(*this == other); }
// Debug utilities.
const char* description() const;
bool IsLessGeneralThan(Truncation other) {
return LessGeneral(kind(), other.kind()) &&
LessGeneralIdentifyZeros(identify_zeros(), other.identify_zeros());
IdentifyZeros identify_zeros() const { return identify_zeros_; }
enum class TruncationKind : uint8_t {
explicit Truncation(TruncationKind kind, IdentifyZeros identify_zeros)
: kind_(kind), identify_zeros_(identify_zeros) {
DCHECK(kind == TruncationKind::kAny || kind == TruncationKind::kFloat64 ||
identify_zeros == kIdentifyZeros);
TruncationKind kind() const { return kind_; }
TruncationKind kind_;
IdentifyZeros identify_zeros_;
static TruncationKind Generalize(TruncationKind rep1, TruncationKind rep2);
static IdentifyZeros GeneralizeIdentifyZeros(IdentifyZeros i1,
IdentifyZeros i2);
static bool LessGeneral(TruncationKind rep1, TruncationKind rep2);
static bool LessGeneralIdentifyZeros(IdentifyZeros u1, IdentifyZeros u2);
enum class TypeCheckKind : uint8_t {
inline std::ostream& operator<<(std::ostream& os, TypeCheckKind type_check) {
switch (type_check) {
case TypeCheckKind::kNone:
return os << "None";
case TypeCheckKind::kSignedSmall:
return os << "SignedSmall";
case TypeCheckKind::kSigned32:
return os << "Signed32";
case TypeCheckKind::kNumber:
return os << "Number";
case TypeCheckKind::kNumberOrOddball:
return os << "NumberOrOddball";
case TypeCheckKind::kHeapObject:
return os << "HeapObject";
// The {UseInfo} class is used to describe a use of an input of a node.
// This information is used in two different ways, based on the phase:
// 1. During propagation, the use info is used to inform the input node
// about what part of the input is used (we call this truncation) and what
// is the preferred representation. For conversions that will require
// checks, we also keep track of whether a minus zero check is needed.
// 2. During lowering, the use info is used to properly convert the input
// to the preferred representation. The preferred representation might be
// insufficient to do the conversion (e.g. word32->float64 conv), so we also
// need the signedness information to produce the correct value.
class UseInfo {
UseInfo(MachineRepresentation representation, Truncation truncation,
TypeCheckKind type_check = TypeCheckKind::kNone)
: representation_(representation),
type_check_(type_check) {}
static UseInfo TruncatingWord32() {
return UseInfo(MachineRepresentation::kWord32, Truncation::Word32());
static UseInfo TruncatingWord64() {
return UseInfo(MachineRepresentation::kWord64, Truncation::Word64());
static UseInfo Bool() {
return UseInfo(MachineRepresentation::kBit, Truncation::Bool());
static UseInfo Float32() {
return UseInfo(MachineRepresentation::kFloat32, Truncation::Any());
static UseInfo TruncatingFloat64() {
return UseInfo(MachineRepresentation::kFloat64, Truncation::Float64());
static UseInfo PointerInt() {
return kPointerSize == 4 ? TruncatingWord32() : TruncatingWord64();
static UseInfo AnyTagged() {
return UseInfo(MachineRepresentation::kTagged, Truncation::Any());
static UseInfo TaggedSigned() {
return UseInfo(MachineRepresentation::kTaggedSigned, Truncation::Any());
static UseInfo TaggedPointer() {
return UseInfo(MachineRepresentation::kTaggedPointer, Truncation::Any());
// Possibly deoptimizing conversions.
static UseInfo CheckedHeapObjectAsTaggedPointer() {
return UseInfo(MachineRepresentation::kTaggedPointer, Truncation::Any(),
static UseInfo CheckedSignedSmallAsTaggedSigned() {
return UseInfo(MachineRepresentation::kTaggedSigned, Truncation::Any(),
static UseInfo CheckedSignedSmallAsWord32(IdentifyZeros identify_zeros) {
return UseInfo(MachineRepresentation::kWord32,
static UseInfo CheckedSigned32AsWord32(IdentifyZeros identify_zeros) {
return UseInfo(MachineRepresentation::kWord32,
Truncation::Any(identify_zeros), TypeCheckKind::kSigned32);
static UseInfo CheckedNumberAsFloat64() {
return UseInfo(MachineRepresentation::kFloat64, Truncation::Any(),
static UseInfo CheckedNumberAsWord32() {
return UseInfo(MachineRepresentation::kWord32, Truncation::Word32(),
static UseInfo CheckedNumberOrOddballAsFloat64() {
return UseInfo(MachineRepresentation::kFloat64, Truncation::Any(),
static UseInfo CheckedNumberOrOddballAsWord32() {
return UseInfo(MachineRepresentation::kWord32, Truncation::Word32(),
// Undetermined representation.
static UseInfo Any() {
return UseInfo(MachineRepresentation::kNone, Truncation::Any());
static UseInfo AnyTruncatingToBool() {
return UseInfo(MachineRepresentation::kNone, Truncation::Bool());
// Value not used.
static UseInfo None() {
return UseInfo(MachineRepresentation::kNone, Truncation::None());
MachineRepresentation representation() const { return representation_; }
Truncation truncation() const { return truncation_; }
TypeCheckKind type_check() const { return type_check_; }
CheckForMinusZeroMode minus_zero_check() const {
return truncation().IdentifiesZeroAndMinusZero()
? CheckForMinusZeroMode::kDontCheckForMinusZero
: CheckForMinusZeroMode::kCheckForMinusZero;
MachineRepresentation representation_;
Truncation truncation_;
TypeCheckKind type_check_;
// Contains logic related to changing the representation of values for constants
// and other nodes, as well as lowering Simplified->Machine operators.
// Eagerly folds any representation changes for constants.
class RepresentationChanger final {
RepresentationChanger(JSGraph* jsgraph, Isolate* isolate)
: jsgraph_(jsgraph),
type_error_(false) {}
// Changes representation from {output_type} to {use_rep}. The {truncation}
// parameter is only used for sanity checking - if the changer cannot figure
// out signedness for the word32->float64 conversion, then we check that the
// uses truncate to word32 (so they do not care about signedness).
Node* GetRepresentationFor(Node* node, MachineRepresentation output_rep,
Type* output_type, Node* use_node,
UseInfo use_info);
const Operator* Int32OperatorFor(IrOpcode::Value opcode);
const Operator* Int32OverflowOperatorFor(IrOpcode::Value opcode);
const Operator* TaggedSignedOperatorFor(IrOpcode::Value opcode);
const Operator* Uint32OperatorFor(IrOpcode::Value opcode);
const Operator* Uint32OverflowOperatorFor(IrOpcode::Value opcode);
const Operator* Float64OperatorFor(IrOpcode::Value opcode);
MachineType TypeForBasePointer(const FieldAccess& access) {
return access.tag() != 0 ? MachineType::AnyTagged()
: MachineType::Pointer();
MachineType TypeForBasePointer(const ElementAccess& access) {
return access.tag() != 0 ? MachineType::AnyTagged()
: MachineType::Pointer();
JSGraph* jsgraph_;
Isolate* isolate_;
friend class RepresentationChangerTester; // accesses the below fields.
bool testing_type_errors_; // If {true}, don't abort on a type error.
bool type_error_; // Set when a type error is detected.
Node* GetTaggedSignedRepresentationFor(Node* node,
MachineRepresentation output_rep,
Type* output_type, Node* use_node,
UseInfo use_info);
Node* GetTaggedPointerRepresentationFor(Node* node,
MachineRepresentation output_rep,
Type* output_type, Node* use_node,
UseInfo use_info);
Node* GetTaggedRepresentationFor(Node* node, MachineRepresentation output_rep,
Type* output_type, Truncation truncation);
Node* GetFloat32RepresentationFor(Node* node,
MachineRepresentation output_rep,
Type* output_type, Truncation truncation);
Node* GetFloat64RepresentationFor(Node* node,
MachineRepresentation output_rep,
Type* output_type, Node* use_node,
UseInfo use_info);
Node* GetWord32RepresentationFor(Node* node, MachineRepresentation output_rep,
Type* output_type, Node* use_node,
UseInfo use_info);
Node* GetBitRepresentationFor(Node* node, MachineRepresentation output_rep,
Type* output_type);
Node* GetWord64RepresentationFor(Node* node, MachineRepresentation output_rep,
Type* output_type);
Node* TypeError(Node* node, MachineRepresentation output_rep,
Type* output_type, MachineRepresentation use);
Node* MakeTruncatedInt32Constant(double value);
Node* InsertChangeBitToTagged(Node* node);
Node* InsertChangeFloat32ToFloat64(Node* node);
Node* InsertChangeFloat64ToInt32(Node* node);
Node* InsertChangeFloat64ToUint32(Node* node);
Node* InsertChangeInt32ToFloat64(Node* node);
Node* InsertChangeTaggedSignedToInt32(Node* node);
Node* InsertChangeTaggedToFloat64(Node* node);
Node* InsertChangeUint32ToFloat64(Node* node);
Node* InsertConversion(Node* node, const Operator* op, Node* use_node);
JSGraph* jsgraph() const { return jsgraph_; }
Isolate* isolate() const { return isolate_; }
Factory* factory() const { return isolate()->factory(); }
SimplifiedOperatorBuilder* simplified() { return jsgraph()->simplified(); }
MachineOperatorBuilder* machine() { return jsgraph()->machine(); }
} // namespace compiler
} // namespace internal
} // namespace v8