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977 lines (785 loc) · 36 KB
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// Copyright 2017 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.
#ifndef V8_OBJECTS_FIXED_ARRAY_H_
#define V8_OBJECTS_FIXED_ARRAY_H_
#include "src/handles/maybe-handles.h"
#include "src/objects/heap-object.h"
#include "src/objects/instance-type.h"
#include "src/objects/maybe-object.h"
#include "src/objects/objects.h"
#include "src/objects/smi.h"
#include "src/objects/tagged.h"
#include "src/objects/trusted-object.h"
#include "src/roots/roots.h"
#include "src/utils/memcopy.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
#include "torque-generated/src/objects/fixed-array-tq.inc"
// Derived: must have a Smi slot at kCapacityOffset.
template <class Derived, class ShapeT, class Super = HeapObject>
class TaggedArrayBase : public Super {
static_assert(std::is_base_of<HeapObject, Super>::value);
OBJECT_CONSTRUCTORS(TaggedArrayBase, Super);
using ElementT = typename ShapeT::ElementT;
static_assert(ShapeT::kElementSize == kTaggedSize);
static_assert(is_subtype_v<ElementT, MaybeObject>);
using ElementFieldT =
TaggedField<ElementT, 0, typename ShapeT::CompressionScheme>;
template <typename ElementT>
static constexpr bool kSupportsSmiElements =
std::is_convertible_v<Smi, ElementT>;
static constexpr WriteBarrierMode kDefaultMode =
std::is_same_v<ElementT, Smi> ? SKIP_WRITE_BARRIER : UPDATE_WRITE_BARRIER;
public:
static constexpr bool kElementsAreMaybeObject = is_maybe_weak_v<ElementT>;
private:
using SlotType =
std::conditional_t<kElementsAreMaybeObject, MaybeObjectSlot, ObjectSlot>;
public:
using Shape = ShapeT;
inline int capacity() const;
inline int capacity(AcquireLoadTag) const;
inline void set_capacity(int value);
inline void set_capacity(int value, ReleaseStoreTag);
// For most arraylike objects, length equals capacity. Provide these
// convenience accessors:
template <typename T = Shape,
typename = std::enable_if<T::kLengthEqualsCapacity>>
inline int length() const;
template <typename T = Shape,
typename = std::enable_if<T::kLengthEqualsCapacity>>
inline int length(AcquireLoadTag tag) const;
template <typename T = Shape,
typename = std::enable_if<T::kLengthEqualsCapacity>>
inline void set_length(int value);
template <typename T = Shape,
typename = std::enable_if<T::kLengthEqualsCapacity>>
inline void set_length(int value, ReleaseStoreTag tag);
inline Tagged<ElementT> get(int index) const;
inline Tagged<ElementT> get(int index, RelaxedLoadTag) const;
inline Tagged<ElementT> get(int index, AcquireLoadTag) const;
inline Tagged<ElementT> get(int index, SeqCstAccessTag) const;
inline void set(int index, Tagged<ElementT> value,
WriteBarrierMode mode = kDefaultMode);
template <typename T = ElementT,
typename = std::enable_if<kSupportsSmiElements<T>>>
inline void set(int index, Tagged<Smi> value);
inline void set(int index, Tagged<ElementT> value, RelaxedStoreTag,
WriteBarrierMode mode = kDefaultMode);
template <typename T = ElementT,
typename = std::enable_if<kSupportsSmiElements<T>>>
inline void set(int index, Tagged<Smi> value, RelaxedStoreTag);
inline void set(int index, Tagged<ElementT> value, ReleaseStoreTag,
WriteBarrierMode mode = kDefaultMode);
template <typename T = ElementT,
typename = std::enable_if<kSupportsSmiElements<T>>>
inline void set(int index, Tagged<Smi> value, ReleaseStoreTag);
inline void set(int index, Tagged<ElementT> value, SeqCstAccessTag,
WriteBarrierMode mode = kDefaultMode);
template <typename T = ElementT,
typename = std::enable_if<kSupportsSmiElements<T>>>
inline void set(int index, Tagged<Smi> value, SeqCstAccessTag);
inline Tagged<ElementT> swap(int index, Tagged<ElementT> value,
SeqCstAccessTag,
WriteBarrierMode mode = kDefaultMode);
inline Tagged<ElementT> compare_and_swap(
int index, Tagged<ElementT> expected, Tagged<ElementT> value,
SeqCstAccessTag, WriteBarrierMode mode = kDefaultMode);
// Move vs. Copy behaves like memmove vs. memcpy: for Move, the memory
// regions may overlap, for Copy they must not overlap.
inline static void MoveElements(Isolate* isolate, Tagged<Derived> dst,
int dst_index, Tagged<Derived> src,
int src_index, int len,
WriteBarrierMode mode = kDefaultMode);
inline static void CopyElements(Isolate* isolate, Tagged<Derived> dst,
int dst_index, Tagged<Derived> src,
int src_index, int len,
WriteBarrierMode mode = kDefaultMode);
// Right-trim the array.
// Invariant: 0 < new_length <= length()
inline void RightTrim(Isolate* isolate, int new_capacity);
inline int AllocatedSize() const;
static inline constexpr int SizeFor(int capacity) {
return Shape::kHeaderSize + capacity * Shape::kElementSize;
}
static inline constexpr int OffsetOfElementAt(int index) {
return SizeFor(index);
}
// Gives access to raw memory which stores the array's data.
inline SlotType RawFieldOfFirstElement() const;
inline SlotType RawFieldOfElementAt(int index) const;
// Maximal allowed capacity, in number of elements. Chosen s.t. the size fits
// into a Smi which is necessary for being able to create a free space
// filler.
// TODO(jgruber): The kMaxCapacity could be larger (`(Smi::kMaxValue -
// Shape::kHeaderSize) / Shape::kElementSize`), but our tests rely on a
// smaller maximum to avoid timeouts.
static constexpr int kMaxCapacity =
128 * MB - Super::kHeaderSize / Shape::kElementSize;
static_assert(Smi::IsValid(SizeFor(kMaxCapacity)));
// Maximally allowed length for regular (non large object space) object.
static constexpr int kMaxRegularCapacity =
(kMaxRegularHeapObjectSize - Shape::kHeaderSize) / Shape::kElementSize;
static_assert(kMaxRegularCapacity < kMaxCapacity);
// Object layout.
static constexpr int kCapacityOffset = Shape::kCapacityOffset;
static constexpr int kHeaderSize = Shape::kHeaderSize;
static constexpr int kObjectsOffset = kHeaderSize;
protected:
template <class IsolateT>
static Handle<Derived> Allocate(
IsolateT* isolate, int capacity,
base::Optional<DisallowGarbageCollection>* no_gc_out,
AllocationType allocation = AllocationType::kYoung);
static constexpr int NewCapacityForIndex(int index, int old_capacity);
inline void ConditionalWriteBarrier(Tagged<HeapObject> object, int offset,
Tagged<ElementT> value,
WriteBarrierMode mode);
inline bool IsInBounds(int index) const;
inline bool IsCowArray() const;
};
class TaggedArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kTaggedSize;
using ElementT = Object;
using CompressionScheme = V8HeapCompressionScheme;
static constexpr RootIndex kMapRootIndex = RootIndex::kFixedArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kCapacityOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// FixedArray describes fixed-sized arrays with element type Object.
class FixedArray : public TaggedArrayBase<FixedArray, TaggedArrayShape> {
using Super = TaggedArrayBase<FixedArray, TaggedArrayShape>;
OBJECT_CONSTRUCTORS(FixedArray, Super);
public:
template <class IsolateT>
static inline Handle<FixedArray> New(
IsolateT* isolate, int capacity,
AllocationType allocation = AllocationType::kYoung);
using Super::CopyElements;
using Super::MoveElements;
// TODO(jgruber): Only needed for FixedArrays used as JSObject elements.
inline void MoveElements(Isolate* isolate, int dst_index, int src_index,
int len, WriteBarrierMode mode);
inline void CopyElements(Isolate* isolate, int dst_index,
Tagged<FixedArray> src, int src_index, int len,
WriteBarrierMode mode);
// Return a grown copy if the index is bigger than the array's length.
V8_EXPORT_PRIVATE static Handle<FixedArray> SetAndGrow(
Isolate* isolate, Handle<FixedArray> array, int index,
Handle<Object> value);
// Right-trim the array.
// Invariant: 0 < new_length <= length()
V8_EXPORT_PRIVATE void RightTrim(Isolate* isolate, int new_capacity);
// Right-trims the array, and canonicalizes length 0 to empty_fixed_array.
static Handle<FixedArray> RightTrimOrEmpty(Isolate* isolate,
Handle<FixedArray> array,
int new_length);
// TODO(jgruber): Only needed for FixedArrays used as JSObject elements.
inline void FillWithHoles(int from, int to);
// For compatibility with FixedDoubleArray:
// TODO(jgruber): Only needed for FixedArrays used as JSObject elements.
inline bool is_the_hole(Isolate* isolate, int index);
inline void set_the_hole(Isolate* isolate, int index);
inline void set_the_hole(ReadOnlyRoots ro_roots, int index);
static_assert(kHeaderSize == Internals::kFixedArrayHeaderSize);
DECL_CAST(FixedArray)
DECL_PRINTER(FixedArray)
DECL_VERIFIER(FixedArray)
class BodyDescriptor;
static constexpr int kLengthOffset = Shape::kCapacityOffset;
static constexpr int kMaxLength = FixedArray::kMaxCapacity;
static constexpr int kMaxRegularLength = FixedArray::kMaxRegularCapacity;
private:
inline static Handle<FixedArray> Resize(
Isolate* isolate, Handle<FixedArray> xs, int new_capacity,
AllocationType allocation = AllocationType::kYoung,
WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
};
class TrustedArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kTaggedSize;
using ElementT = Object;
using CompressionScheme = V8HeapCompressionScheme;
static constexpr RootIndex kMapRootIndex = RootIndex::kTrustedFixedArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kCapacityOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(TrustedObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// A FixedArray in trusted space and with a unique instance type.
//
// Note: while the array itself is trusted, it contains tagged pointers into
// the main pointer compression heap and therefore to _untrusted_ objects.
// If you are storing references to other trusted object (i.e. protected
// pointers), use ProtectedFixedArray.
class TrustedFixedArray
: public TaggedArrayBase<TrustedFixedArray, TrustedArrayShape,
TrustedObject> {
using Super =
TaggedArrayBase<TrustedFixedArray, TrustedArrayShape, TrustedObject>;
OBJECT_CONSTRUCTORS(TrustedFixedArray, Super);
public:
template <class IsolateT>
static inline Handle<TrustedFixedArray> New(IsolateT* isolate, int capacity);
DECL_CAST(TrustedFixedArray)
DECL_PRINTER(TrustedFixedArray)
DECL_VERIFIER(TrustedFixedArray)
class BodyDescriptor;
static constexpr int kLengthOffset =
TrustedFixedArray::Shape::kCapacityOffset;
static constexpr int kMaxLength = TrustedFixedArray::kMaxCapacity;
static constexpr int kMaxRegularLength =
TrustedFixedArray::kMaxRegularCapacity;
};
class ProtectedArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kTaggedSize;
// Elements are of type TrustedObject or Smi, so we must declare it as Object
// here.
using ElementT = Object;
using CompressionScheme = TrustedSpaceCompressionScheme;
static constexpr RootIndex kMapRootIndex = RootIndex::kProtectedFixedArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kCapacityOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(TrustedObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// A FixedArray in trusted space, holding protected pointers (to other trusted
// objects). If you want to store JS-heap references, use TrustedFixedArray.
// ProtectedFixedArray has a unique instance type.
class ProtectedFixedArray
: public TaggedArrayBase<ProtectedFixedArray, ProtectedArrayShape,
TrustedObject> {
using Super =
TaggedArrayBase<ProtectedFixedArray, ProtectedArrayShape, TrustedObject>;
OBJECT_CONSTRUCTORS(ProtectedFixedArray, Super);
public:
// Allocate a new ProtectedFixedArray of the given capacity, initialized with
// Smi::zero().
template <class IsolateT>
static inline Handle<ProtectedFixedArray> New(IsolateT* isolate,
int capacity);
DECL_CAST(ProtectedFixedArray)
DECL_PRINTER(ProtectedFixedArray)
DECL_VERIFIER(ProtectedFixedArray)
class BodyDescriptor;
static constexpr int kLengthOffset =
ProtectedFixedArray::Shape::kCapacityOffset;
static constexpr int kMaxLength = ProtectedFixedArray::kMaxCapacity;
static constexpr int kMaxRegularLength =
ProtectedFixedArray::kMaxRegularCapacity;
};
// FixedArray alias added only because of IsFixedArrayExact() predicate, which
// checks for the exact instance type FIXED_ARRAY_TYPE instead of a range
// check: [FIRST_FIXED_ARRAY_TYPE, LAST_FIXED_ARRAY_TYPE].
class FixedArrayExact final : public FixedArray {};
// Common superclass for FixedArrays that allow implementations to share common
// accessors and some code paths. Note that due to single-inheritance
// restrictions, it is not part of the actual type hierarchy. Instead, we slot
// it in with manual is_subtype specializations in tagged.h.
// TODO(jgruber): This class is really specific to FixedArrays used as
// elements backing stores and should not be part of the common FixedArray
// hierarchy.
class FixedArrayBase : public HeapObject {
OBJECT_CONSTRUCTORS(FixedArrayBase, HeapObject);
public:
// TODO(jgruber): Remove these `length` accessors once all subclasses have
// been ported to use TaggedArrayBase or similar.
inline int length() const;
inline int length(AcquireLoadTag tag) const;
inline void set_length(int value);
inline void set_length(int value, ReleaseStoreTag tag);
static constexpr int kLengthOffset = HeapObject::kHeaderSize;
static constexpr int kHeaderSize = kLengthOffset + kTaggedSize;
static constexpr int kMaxLength = FixedArray::kMaxCapacity;
static constexpr int kMaxRegularLength = FixedArray::kMaxRegularCapacity;
static int GetMaxLengthForNewSpaceAllocation(ElementsKind kind);
V8_EXPORT_PRIVATE bool IsCowArray() const;
// Maximal allowed size, in bytes, of a single FixedArrayBase. Prevents
// overflowing size computations, as well as extreme memory consumption.
static constexpr int kMaxSize = 128 * kTaggedSize * MB;
static_assert(Smi::IsValid(kMaxSize));
DECL_CAST(FixedArrayBase)
DECL_VERIFIER(FixedArrayBase)
};
// Derived: must have a Smi slot at kCapacityOffset.
template <class Derived, class ShapeT, class Super = HeapObject>
class PrimitiveArrayBase : public Super {
static_assert(std::is_base_of<HeapObject, Super>::value);
OBJECT_CONSTRUCTORS(PrimitiveArrayBase, Super);
using ElementT = typename ShapeT::ElementT;
static_assert(!is_subtype_v<ElementT, Object>);
public:
using Shape = ShapeT;
static constexpr bool kElementsAreMaybeObject = false;
inline int length() const;
inline int length(AcquireLoadTag) const;
inline void set_length(int value);
inline void set_length(int value, ReleaseStoreTag);
// For compatibility with TaggedArrayBase:
inline int capacity() const;
inline int capacity(AcquireLoadTag) const;
inline void set_capacity(int value);
inline void set_capacity(int value, ReleaseStoreTag);
inline ElementT get(int index) const;
inline void set(int index, ElementT value);
inline int AllocatedSize() const;
static inline constexpr int SizeFor(int length) {
return OBJECT_POINTER_ALIGN(OffsetOfElementAt(length));
}
static inline constexpr int OffsetOfElementAt(int index) {
return Shape::kHeaderSize + index * Shape::kElementSize;
}
// Gives access to raw memory which stores the array's data.
// Note that on 32-bit archs and on 64-bit platforms with pointer compression
// the pointers to 8-byte size elements are not guaranteed to be aligned.
inline ElementT* AddressOfElementAt(int index) const;
inline ElementT* begin() const;
inline ElementT* end() const;
inline int DataSize() const;
static inline Tagged<Derived> FromAddressOfFirstElement(Address address);
// Maximal allowed length, in number of elements. Chosen s.t. the size fits
// into a Smi which is necessary for being able to create a free space
// filler.
// TODO(jgruber): The kMaxLength could be larger (`(Smi::kMaxValue -
// Shape::kHeaderSize) / Shape::kElementSize`), but our tests rely on a
// smaller maximum to avoid timeouts.
static constexpr int kMaxLength =
(FixedArrayBase::kMaxSize - Super::kHeaderSize) / Shape::kElementSize;
static_assert(Smi::IsValid(SizeFor(kMaxLength)));
// Maximally allowed length for regular (non large object space) object.
static constexpr int kMaxRegularLength =
(kMaxRegularHeapObjectSize - Shape::kHeaderSize) / Shape::kElementSize;
static_assert(kMaxRegularLength < kMaxLength);
// Object layout.
static constexpr int kLengthOffset = Shape::kLengthOffset;
static constexpr int kHeaderSize = Shape::kHeaderSize;
protected:
template <class IsolateT>
static Handle<Derived> Allocate(
IsolateT* isolate, int length,
base::Optional<DisallowGarbageCollection>* no_gc_out,
AllocationType allocation = AllocationType::kYoung);
inline bool IsInBounds(int index) const;
};
class FixedDoubleArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kDoubleSize;
using ElementT = double;
static constexpr RootIndex kMapRootIndex = RootIndex::kFixedDoubleArrayMap;
#define FIELD_LIST(V) \
V(kLengthOffset, kTaggedSize) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// FixedDoubleArray describes fixed-sized arrays with element type double.
class FixedDoubleArray
: public PrimitiveArrayBase<FixedDoubleArray, FixedDoubleArrayShape> {
using Super = PrimitiveArrayBase<FixedDoubleArray, FixedDoubleArrayShape>;
OBJECT_CONSTRUCTORS(FixedDoubleArray, Super);
public:
// Note this returns FixedArrayBase due to canonicalization to
// empty_fixed_array.
template <class IsolateT>
static inline Handle<FixedArrayBase> New(
IsolateT* isolate, int capacity,
AllocationType allocation = AllocationType::kYoung);
// Setter and getter for elements.
inline double get_scalar(int index);
inline uint64_t get_representation(int index);
static inline Handle<Object> get(Tagged<FixedDoubleArray> array, int index,
Isolate* isolate);
inline void set(int index, double value);
inline void set_the_hole(Isolate* isolate, int index);
inline void set_the_hole(int index);
inline bool is_the_hole(Isolate* isolate, int index);
inline bool is_the_hole(int index);
inline void MoveElements(Isolate* isolate, int dst_index, int src_index,
int len, WriteBarrierMode /* unused */);
inline void FillWithHoles(int from, int to);
DECL_CAST(FixedDoubleArray)
DECL_PRINTER(FixedDoubleArray)
DECL_VERIFIER(FixedDoubleArray)
class BodyDescriptor;
static constexpr int kFloatsOffset = Shape::kHeaderSize;
};
class WeakFixedArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kTaggedSize;
using ElementT = MaybeObject;
using CompressionScheme = V8HeapCompressionScheme;
static constexpr RootIndex kMapRootIndex = RootIndex::kWeakFixedArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kCapacityOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// WeakFixedArray describes fixed-sized arrays with element type
// Tagged<MaybeObject>.
class WeakFixedArray
: public TaggedArrayBase<WeakFixedArray, WeakFixedArrayShape> {
using Super = TaggedArrayBase<WeakFixedArray, WeakFixedArrayShape>;
OBJECT_CONSTRUCTORS(WeakFixedArray, Super);
public:
template <class IsolateT>
static inline Handle<WeakFixedArray> New(
IsolateT* isolate, int capacity,
AllocationType allocation = AllocationType::kYoung);
DECL_CAST(WeakFixedArray)
DECL_PRINTER(WeakFixedArray)
DECL_VERIFIER(WeakFixedArray)
class BodyDescriptor;
static constexpr int kLengthOffset = Shape::kCapacityOffset;
};
// WeakArrayList is like a WeakFixedArray with static convenience methods for
// adding more elements. length() returns the number of elements in the list and
// capacity() returns the allocated size. The number of elements is stored at
// kLengthOffset and is updated with every insertion. The array grows
// dynamically with O(1) amortized insertion.
class WeakArrayList
: public TorqueGeneratedWeakArrayList<WeakArrayList, HeapObject> {
public:
NEVER_READ_ONLY_SPACE
DECL_PRINTER(WeakArrayList)
V8_EXPORT_PRIVATE static Handle<WeakArrayList> AddToEnd(
Isolate* isolate, Handle<WeakArrayList> array, MaybeObjectHandle value);
// A version that adds to elements. This ensures that the elements are
// inserted atomically w.r.t GC.
V8_EXPORT_PRIVATE static Handle<WeakArrayList> AddToEnd(
Isolate* isolate, Handle<WeakArrayList> array, MaybeObjectHandle value1,
Tagged<Smi> value2);
// Appends an element to the array and possibly compacts and shrinks live weak
// references to the start of the collection. Only use this method when
// indices to elements can change.
static V8_WARN_UNUSED_RESULT Handle<WeakArrayList> Append(
Isolate* isolate, Handle<WeakArrayList> array, MaybeObjectHandle value,
AllocationType allocation = AllocationType::kYoung);
// Compact weak references to the beginning of the array.
V8_EXPORT_PRIVATE void Compact(Isolate* isolate);
inline Tagged<MaybeObject> Get(int index) const;
inline Tagged<MaybeObject> Get(PtrComprCageBase cage_base, int index) const;
// TODO(jgruber): Remove this once it's no longer needed for compatibility
// with WeakFixedArray.
inline Tagged<MaybeObject> get(int index) const;
// Set the element at index to obj. The underlying array must be large enough.
// If you need to grow the WeakArrayList, use the static AddToEnd() method
// instead.
inline void Set(int index, Tagged<MaybeObject> value,
WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
inline void Set(int index, Tagged<Smi> value);
static constexpr int SizeForCapacity(int capacity) {
return SizeFor(capacity);
}
static constexpr int CapacityForLength(int length) {
return length + std::max(length / 2, 2);
}
// Gives access to raw memory which stores the array's data.
inline MaybeObjectSlot data_start();
inline void CopyElements(Isolate* isolate, int dst_index,
Tagged<WeakArrayList> src, int src_index, int len,
WriteBarrierMode mode);
V8_EXPORT_PRIVATE bool IsFull() const;
inline int AllocatedSize() const;
class BodyDescriptor;
static const int kMaxCapacity =
(FixedArrayBase::kMaxSize - kHeaderSize) / kTaggedSize;
static Handle<WeakArrayList> EnsureSpace(
Isolate* isolate, Handle<WeakArrayList> array, int length,
AllocationType allocation = AllocationType::kYoung);
// Returns the number of non-cleaned weak references in the array.
int CountLiveWeakReferences() const;
// Returns the number of non-cleaned elements in the array.
int CountLiveElements() const;
// Returns whether an entry was found and removed. Will move the elements
// around in the array - this method can only be used in cases where the user
// doesn't care about the indices! Users should make sure there are no
// duplicates.
V8_EXPORT_PRIVATE bool RemoveOne(MaybeObjectHandle value);
// Searches the array (linear time) and returns whether it contains the value.
V8_EXPORT_PRIVATE bool Contains(Tagged<MaybeObject> value);
class Iterator;
private:
static int OffsetOfElementAt(int index) {
return kHeaderSize + index * kTaggedSize;
}
TQ_OBJECT_CONSTRUCTORS(WeakArrayList)
};
class WeakArrayList::Iterator {
public:
explicit Iterator(Tagged<WeakArrayList> array) : index_(0), array_(array) {}
Iterator(const Iterator&) = delete;
Iterator& operator=(const Iterator&) = delete;
inline Tagged<HeapObject> Next();
private:
int index_;
Tagged<WeakArrayList> array_;
DISALLOW_GARBAGE_COLLECTION(no_gc_)
};
class ArrayListShape final : public AllStatic {
public:
static constexpr int kElementSize = kTaggedSize;
using ElementT = Object;
using CompressionScheme = V8HeapCompressionScheme;
static constexpr RootIndex kMapRootIndex = RootIndex::kArrayListMap;
static constexpr bool kLengthEqualsCapacity = false;
#define FIELD_LIST(V) \
V(kCapacityOffset, kTaggedSize) \
V(kLengthOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// A generic array that grows dynamically with O(1) amortized insertion.
class ArrayList : public TaggedArrayBase<ArrayList, ArrayListShape> {
using Super = TaggedArrayBase<ArrayList, ArrayListShape>;
OBJECT_CONSTRUCTORS(ArrayList, Super);
public:
using Shape = ArrayListShape;
template <class IsolateT>
static inline Handle<ArrayList> New(
IsolateT* isolate, int capacity,
AllocationType allocation = AllocationType::kYoung);
inline int length() const;
inline void set_length(int value);
V8_EXPORT_PRIVATE static Handle<ArrayList> Add(
Isolate* isolate, Handle<ArrayList> array, Tagged<Smi> obj,
AllocationType allocation = AllocationType::kYoung);
V8_EXPORT_PRIVATE static Handle<ArrayList> Add(
Isolate* isolate, Handle<ArrayList> array, Handle<Object> obj,
AllocationType allocation = AllocationType::kYoung);
V8_EXPORT_PRIVATE static Handle<ArrayList> Add(
Isolate* isolate, Handle<ArrayList> array, Handle<Object> obj0,
Handle<Object> obj1, AllocationType allocation = AllocationType::kYoung);
V8_EXPORT_PRIVATE static Handle<FixedArray> ToFixedArray(
Isolate* isolate, Handle<ArrayList> array,
AllocationType allocation = AllocationType::kYoung);
// Right-trim the array.
// Invariant: 0 < new_length <= length()
void RightTrim(Isolate* isolate, int new_capacity);
DECL_CAST(ArrayList)
DECL_PRINTER(ArrayList)
DECL_VERIFIER(ArrayList)
class BodyDescriptor;
static constexpr int kLengthOffset = Shape::kLengthOffset;
private:
static Handle<ArrayList> EnsureSpace(
Isolate* isolate, Handle<ArrayList> array, int length,
AllocationType allocation = AllocationType::kYoung);
};
enum SearchMode { ALL_ENTRIES, VALID_ENTRIES };
template <SearchMode search_mode, typename T>
inline int Search(T* array, Tagged<Name> name, int valid_entries = 0,
int* out_insertion_index = nullptr,
bool concurrent_search = false);
class ByteArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kUInt8Size;
using ElementT = uint8_t;
static constexpr RootIndex kMapRootIndex = RootIndex::kByteArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kLengthOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// ByteArray represents fixed sized arrays containing raw bytes that will not
// be scanned by the garbage collector.
class ByteArray : public PrimitiveArrayBase<ByteArray, ByteArrayShape> {
using Super = PrimitiveArrayBase<ByteArray, ByteArrayShape>;
OBJECT_CONSTRUCTORS(ByteArray, Super);
public:
using Shape = ByteArrayShape;
template <class IsolateT>
static inline Handle<ByteArray> New(
IsolateT* isolate, int capacity,
AllocationType allocation = AllocationType::kYoung);
inline uint32_t get_int(int offset) const;
inline void set_int(int offset, uint32_t value);
// Given the full object size in bytes, return the length that should be
// passed to New s.t. an object of the same size is created.
static constexpr int LengthFor(int size_in_bytes) {
DCHECK(IsAligned(size_in_bytes, kTaggedSize));
DCHECK_GE(size_in_bytes, Shape::kHeaderSize);
return size_in_bytes - Shape::kHeaderSize;
}
DECL_CAST(ByteArray)
DECL_PRINTER(ByteArray)
DECL_VERIFIER(ByteArray)
class BodyDescriptor;
static constexpr int kBytesOffset = Shape::kHeaderSize;
};
class TrustedByteArrayShape final : public AllStatic {
public:
static constexpr int kElementSize = kUInt8Size;
using ElementT = uint8_t;
static constexpr RootIndex kMapRootIndex = RootIndex::kTrustedByteArrayMap;
static constexpr bool kLengthEqualsCapacity = true;
#define FIELD_LIST(V) \
V(kLengthOffset, kTaggedSize) \
V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(TrustedObject::kHeaderSize, FIELD_LIST)
#undef FIELD_LIST
};
// A ByteArray in trusted space.
class TrustedByteArray
: public PrimitiveArrayBase<TrustedByteArray, TrustedByteArrayShape,
TrustedObject> {
using Super = PrimitiveArrayBase<TrustedByteArray, TrustedByteArrayShape,
TrustedObject>;
OBJECT_CONSTRUCTORS(TrustedByteArray, Super);
public:
using Shape = TrustedByteArrayShape;
template <class IsolateT>
static inline Handle<TrustedByteArray> New(IsolateT* isolate, int capacity);
// Given the full object size in bytes, return the length that should be
// passed to New s.t. an object of the same size is created.
static constexpr int LengthFor(int size_in_bytes) {
DCHECK(IsAligned(size_in_bytes, kTaggedSize));
DCHECK_GE(size_in_bytes, Shape::kHeaderSize);
return size_in_bytes - Shape::kHeaderSize;
}
DECL_CAST(TrustedByteArray)
DECL_PRINTER(TrustedByteArray)
DECL_VERIFIER(TrustedByteArray)
class BodyDescriptor;
static constexpr int kBytesOffset = Shape::kHeaderSize;
};
// Convenience class for treating a ByteArray as array of fixed-size integers.
template <typename T>
class FixedIntegerArray : public ByteArray {
static_assert(std::is_integral<T>::value);
public:
static Handle<FixedIntegerArray<T>> New(
Isolate* isolate, int length,
AllocationType allocation = AllocationType::kYoung);
// Get/set the contents of this array.
T get(int index) const;
void set(int index, T value);
// Code Generation support.
static constexpr int OffsetOfElementAt(int index) {
return kHeaderSize + index * sizeof(T);
}
inline int length() const;
DECL_CAST(FixedIntegerArray<T>)
OBJECT_CONSTRUCTORS(FixedIntegerArray<T>, ByteArray);
};
using FixedInt8Array = FixedIntegerArray<int8_t>;
using FixedUInt8Array = FixedIntegerArray<uint8_t>;
using FixedInt16Array = FixedIntegerArray<int16_t>;
using FixedUInt16Array = FixedIntegerArray<uint16_t>;
using FixedInt32Array = FixedIntegerArray<int32_t>;
using FixedUInt32Array = FixedIntegerArray<uint32_t>;
using FixedInt64Array = FixedIntegerArray<int64_t>;
using FixedUInt64Array = FixedIntegerArray<uint64_t>;
// Use with care! Raw addresses on the heap are not safe in combination with
// the sandbox. Use an ExternalPointerArray instead. However, this can for
// example be used to store sandboxed pointers, which is safe.
class FixedAddressArray : public FixedIntegerArray<Address> {
public:
// Get/set a sandboxed pointer from this array.
inline Address get_sandboxed_pointer(int offset) const;
inline void set_sandboxed_pointer(int offset, Address value);
static inline Handle<FixedAddressArray> New(
Isolate* isolate, int length,
AllocationType allocation = AllocationType::kYoung);
DECL_CAST(FixedAddressArray)
OBJECT_CONSTRUCTORS(FixedAddressArray, FixedIntegerArray<Address>);
};
// An array containing external pointers.
// When the sandbox is off, this will simply contain system-pointer sized words.
// Otherwise, it contains external pointer handles, i.e. indices into the
// external pointer table.
// This class uses lazily-initialized external pointer slots. As such, its
// content can simply be zero-initialized, and the external pointer table
// entries are only allocated when an element is written to for the first time.
class ExternalPointerArray : public FixedArrayBase {
public:
template <ExternalPointerTag tag>
inline Address get(int index, Isolate* isolate);
template <ExternalPointerTag tag>
inline void set(int index, Isolate* isolate, Address value);
inline void clear(int index);
static inline Handle<ExternalPointerArray> New(
Isolate* isolate, int length,
AllocationType allocation = AllocationType::kYoung);
static constexpr int SizeFor(int length) {
return kHeaderSize + length * kExternalPointerSlotSize;
}
static constexpr int OffsetOfElementAt(int index) {
return kHeaderSize + index * kExternalPointerSlotSize;
}
// Maximal length of a single ExternalPointerArray.
static const int kMaxLength = FixedArrayBase::kMaxSize - kHeaderSize;
static_assert(Internals::IsValidSmi(kMaxLength),
"ExternalPointerArray maxLength not a Smi");
class BodyDescriptor;
static constexpr int kPointersOffset = kHeaderSize;
DECL_CAST(ExternalPointerArray)
DECL_PRINTER(ExternalPointerArray)
DECL_VERIFIER(ExternalPointerArray)
OBJECT_CONSTRUCTORS(ExternalPointerArray, FixedArrayBase);
};
// Wrapper class for ByteArray which can store arbitrary C++ classes, as long
// as they can be copied with memcpy.
template <class T>
class PodArray : public ByteArray {
public:
static Handle<PodArray<T>> New(
Isolate* isolate, int length,
AllocationType allocation = AllocationType::kYoung);
static Handle<PodArray<T>> New(
LocalIsolate* isolate, int length,
AllocationType allocation = AllocationType::kOld);
void copy_out(int index, T* result, int length) {
MemCopy(result, AddressOfElementAt(index * sizeof(T)), length * sizeof(T));
}
void copy_in(int index, const T* buffer, int length) {
MemCopy(AddressOfElementAt(index * sizeof(T)), buffer, length * sizeof(T));
}
bool matches(const T* buffer, int length) {
DCHECK_LE(length, this->length());
return memcmp(begin(), buffer, length * sizeof(T)) == 0;
}
bool matches(int offset, const T* buffer, int length) {
DCHECK_LE(offset, this->length());
DCHECK_LE(offset + length, this->length());
return memcmp(begin() + sizeof(T) * offset, buffer, length * sizeof(T)) ==
0;
}
T get(int index) {
T result;
copy_out(index, &result, 1);
return result;
}
void set(int index, const T& value) { copy_in(index, &value, 1); }
inline int length() const;
DECL_CAST(PodArray<T>)
OBJECT_CONSTRUCTORS(PodArray<T>, ByteArray);
};
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_FIXED_ARRAY_H_