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Copy pathArrayBuffer.cpp
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803 lines (688 loc) · 30.2 KB
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/*
* Copyright (C) 2009-2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "ArrayBuffer.h"
#include "JSArrayBufferView.h"
#include "JSArrayBufferViewInlines.h"
#include "JSCellInlines.h"
#include "JSWebAssemblyInstance.h"
#include "WaiterListManager.h"
#include "WeakInlines.h"
#include <wtf/FastMalloc.h>
#include <wtf/MathExtras.h>
#include <wtf/OSAllocator.h>
#include <wtf/PageBlock.h>
#if ENABLE(WEBASSEMBLY)
#include "WasmMemory.h"
#endif
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
namespace ArrayBufferInternal {
static constexpr bool verbose = false;
}
static void zeroFill(void* base, size_t size)
{
constexpr size_t largeZeroFillThreshold = 1 * MB;
if (size >= largeZeroFillThreshold) {
size_t pageSizeValue = WTF::pageSize();
uintptr_t begin = reinterpret_cast<uintptr_t>(base);
uintptr_t end = begin + size;
uintptr_t pageAlignedBegin = roundUpToMultipleOf(pageSizeValue, begin);
uintptr_t pageAlignedEnd = roundDownToMultipleOf(pageSizeValue, end);
if (pageAlignedEnd > pageAlignedBegin) {
if (begin != pageAlignedBegin)
memset(base, 0, pageAlignedBegin - begin);
OSAllocator::zeroFill(reinterpret_cast<void*>(pageAlignedBegin), pageAlignedEnd - pageAlignedBegin);
if (end != pageAlignedEnd)
memset(reinterpret_cast<void*>(pageAlignedEnd), 0, end - pageAlignedEnd);
} else
memset(base, 0, size);
} else
memset(base, 0, size);
}
Ref<SharedTask<void(void*)>> ArrayBuffer::primitiveGigacageDestructor()
{
static LazyNeverDestroyed<Ref<SharedTask<void(void*)>>> destructor;
static std::once_flag onceKey;
std::call_once(onceKey, [&] {
destructor.construct(createSharedTask<void(void*)>([] (void* p) { Gigacage::free(Gigacage::Primitive, p); }));
});
return destructor.get().copyRef();
}
template<typename Func>
static bool tryAllocate(VM* vm, NOESCAPE const Func& allocate)
{
unsigned numTries = 2;
bool success = false;
for (unsigned i = 0; i < numTries && !success; ++i) {
switch (allocate()) {
case BufferMemoryResult::Kind::Success:
success = true;
break;
case BufferMemoryResult::Kind::SuccessAndNotifyMemoryPressure:
if (vm)
vm->heap.collectAsync(CollectionScope::Full);
success = true;
break;
case BufferMemoryResult::Kind::SyncTryToReclaimMemory:
if (i + 1 == numTries)
break;
if (vm)
vm->heap.collectSync(CollectionScope::Full);
break;
}
}
return success;
}
static RefPtr<BufferMemoryHandle> tryAllocateResizableMemory(VM* vm, size_t sizeInBytes, size_t maxByteLength)
{
// Make sure malloc actually allocates something, but not too much. We use null to mean that the buffer is detached.
size_t initialBytes = roundUpToMultipleOf<PageCount::pageSize>(sizeInBytes);
if (!initialBytes)
initialBytes = PageCount::pageSize;
size_t maximumBytes = roundUpToMultipleOf<PageCount::pageSize>(maxByteLength);
if (!maximumBytes)
maximumBytes = PageCount::pageSize;
// The whole maximum is reserved up front while only the initial size is charged against the
// physical budget, so without this a single buffer could claim all the address space there is.
if (static_cast<uint64_t>(maximumBytes) > maxGrowableBufferReservationBytes)
return nullptr;
bool done = tryAllocate(vm,
[&] () -> BufferMemoryResult::Kind {
return BufferMemoryManager::singleton().tryAllocatePhysicalBytes(initialBytes);
});
if (!done)
return nullptr;
char* slowMemory = nullptr;
tryAllocate(vm,
[&] () -> BufferMemoryResult::Kind {
auto result = BufferMemoryManager::singleton().tryAllocateGrowableBoundsCheckingMemory(maximumBytes);
slowMemory = std::bit_cast<char*>(result.basePtr);
return result.kind;
});
if (!slowMemory) {
BufferMemoryManager::singleton().freePhysicalBytes(initialBytes);
return nullptr;
}
#if OS(WINDOWS)
if (!BufferMemoryManager::tryMakeReadableAndWritable(slowMemory, initialBytes)) {
BufferMemoryManager::singleton().freeGrowableBoundsCheckingMemory(slowMemory, maximumBytes);
BufferMemoryManager::singleton().freePhysicalBytes(initialBytes);
return nullptr;
}
#endif
constexpr bool readable = false;
constexpr bool writable = false;
OSAllocator::protect(slowMemory + initialBytes, maximumBytes - initialBytes, readable, writable);
return adoptRef(*new BufferMemoryHandle(slowMemory, initialBytes, maximumBytes, PageCount::fromBytes(initialBytes), PageCount::fromBytes(maximumBytes), MemorySharingMode::Shared, MemoryMode::BoundsChecking));
}
ArrayBufferContents::ArrayBufferContents(void* data, size_t sizeInBytes, std::optional<size_t> maxByteLength, ArrayBufferDestructorFunction&& destructor)
: m_data(data)
, m_destructor(WTF::move(destructor))
, m_sizeInBytes(sizeInBytes)
, m_maxByteLength(maxByteLength.value_or(sizeInBytes))
, m_hasMaxByteLength(!!maxByteLength)
{
RELEASE_ASSERT(m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
}
ArrayBufferContents::ArrayBufferContents(std::span<const uint8_t> data, std::optional<size_t> maxByteLength, ArrayBufferDestructorFunction&& destructor)
: ArrayBufferContents(const_cast<uint8_t*>(data.data()), data.size(), maxByteLength, WTF::move(destructor))
{
}
ArrayBufferContents::ArrayBufferContents(Ref<SharedArrayBufferContents>&& shared, bool forceFixedLengthIfWasm)
: m_shared(WTF::move(shared))
, m_memoryHandle(m_shared->memoryHandle())
, m_sizeInBytes(m_shared->sizeInBytes(std::memory_order_seq_cst))
{
RELEASE_ASSERT(m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
bool adjustedForceFixedLengthIfWasm = forceFixedLengthIfWasm || !Options::useWasmMemoryToBufferAPIs();
if (m_shared->mode() == SharedArrayBufferContents::Mode::WebAssembly && adjustedForceFixedLengthIfWasm) {
m_hasMaxByteLength = false;
m_maxByteLength = m_sizeInBytes;
} else {
m_hasMaxByteLength = !!m_shared->maxByteLength();
m_maxByteLength = m_shared->maxByteLength().value_or(m_sizeInBytes);
}
// data() cannot destroy m_shared here so the code is safe as is so avoid
// refing for performance reasons.
SUPPRESS_UNCOUNTED_ARG m_data = DataType { m_shared->data() };
}
ArrayBufferContents::ArrayBufferContents(void* data, size_t sizeInBytes, size_t maxByteLength, Ref<BufferMemoryHandle>&& memoryHandle)
: m_data(data)
, m_memoryHandle(WTF::move(memoryHandle))
, m_sizeInBytes(sizeInBytes)
, m_maxByteLength(maxByteLength)
, m_hasMaxByteLength(true)
{
RELEASE_ASSERT(m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
}
void ArrayBufferContents::tryAllocate(size_t numElements, unsigned elementByteSize, InitializationPolicy policy)
{
CheckedSize sizeInBytes = numElements;
sizeInBytes *= elementByteSize;
if (sizeInBytes.hasOverflowed() || sizeInBytes.value() > MAX_ARRAY_BUFFER_SIZE) {
reset();
return;
}
size_t allocationSize = sizeInBytes.value();
if (!allocationSize)
allocationSize = 1; // Make sure malloc actually allocates something, but not too much. We use null to mean that the buffer is detached.
void* data = nullptr;
if (policy == InitializationPolicy::ZeroInitialize)
data = Gigacage::tryZeroedMalloc(Gigacage::Primitive, allocationSize);
else
data = Gigacage::tryMalloc(Gigacage::Primitive, allocationSize);
m_data = DataType(data);
if (!data) {
reset();
return;
}
m_sizeInBytes = sizeInBytes.value();
RELEASE_ASSERT(m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
m_maxByteLength = m_sizeInBytes;
m_hasMaxByteLength = false;
m_destructor = ArrayBuffer::primitiveGigacageDestructor();
}
void ArrayBufferContents::makeShared()
{
m_shared = SharedArrayBufferContents::create(mutableSpan(), maxByteLength(), m_memoryHandle, WTF::move(m_destructor), SharedArrayBufferContents::Mode::Default);
m_destructor = nullptr;
}
SharedArrayBufferContents::~SharedArrayBufferContents()
{
WaiterListManager::singleton().unregister(std::bit_cast<uint8_t*>(data()), m_sizeInBytes);
if (RefPtr destructor = m_destructor) {
// FIXME: we shouldn't use getUnsafe here https://bugs.webkit.org/show_bug.cgi?id=197698
destructor->run(m_data.getUnsafe());
}
}
void ArrayBufferContents::copyTo(ArrayBufferContents& other)
{
ASSERT(!other.m_data);
other.tryAllocate(m_sizeInBytes, sizeof(char), ArrayBufferContents::InitializationPolicy::DontInitialize);
if (!other.m_data)
return;
memcpy(other.data(), data(), m_sizeInBytes);
other.m_sizeInBytes = m_sizeInBytes;
RELEASE_ASSERT(other.m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
ASSERT(other.m_maxByteLength <= MAX_ARRAY_BUFFER_SIZE);
}
void ArrayBufferContents::shareWith(ArrayBufferContents& other) const
{
ASSERT(!other.m_data);
ASSERT(m_shared);
other.m_data = m_data;
other.m_destructor = nullptr;
other.m_shared = m_shared;
other.m_memoryHandle = m_memoryHandle;
other.m_sizeInBytes = m_sizeInBytes;
other.m_maxByteLength = m_maxByteLength;
other.m_hasMaxByteLength = m_hasMaxByteLength;
RELEASE_ASSERT(other.m_sizeInBytes <= MAX_ARRAY_BUFFER_SIZE);
ASSERT(other.m_maxByteLength <= MAX_ARRAY_BUFFER_SIZE);
}
Ref<ArrayBuffer> ArrayBuffer::create(size_t numElements, unsigned elementByteSize)
{
auto buffer = tryCreate(numElements, elementByteSize);
if (!buffer)
CRASH();
return buffer.releaseNonNull();
}
Ref<ArrayBuffer> ArrayBuffer::create(ArrayBuffer& other)
{
return ArrayBuffer::create(other.span());
}
Ref<ArrayBuffer> ArrayBuffer::create(std::span<const uint8_t> span)
{
auto buffer = tryCreate(span);
if (!buffer)
CRASH();
return buffer.releaseNonNull();
}
Ref<ArrayBuffer> ArrayBuffer::create(ArrayBufferContents&& contents)
{
return adoptRef(*new ArrayBuffer(WTF::move(contents)));
}
// FIXME: We cannot use this except if the memory comes from the cage.
// Current this is only used from:
// - JSGenericTypedArrayView<>::slowDownAndWasteMemory. But in that case, the memory should have already come
// from the cage.
Ref<ArrayBuffer> ArrayBuffer::createAdopted(std::span<const uint8_t> data)
{
ASSERT(!Gigacage::isEnabled() || (Gigacage::contains(data.data()) && Gigacage::contains(data.data() + data.size() - 1)));
return createFromBytes(data, ArrayBuffer::primitiveGigacageDestructor());
}
// FIXME: We cannot use this except if the memory comes from the cage.
// Currently this is only used from:
// - The C API. We could support that by either having the system switch to a mode where typed arrays are no
// longer caged, or we could introduce a new set of typed array types that are uncaged and get accessed
// differently.
// - WebAssembly. Wasm should allocate from the cage.
Ref<ArrayBuffer> ArrayBuffer::createFromBytes(std::span<const uint8_t> data, ArrayBufferDestructorFunction&& destructor)
{
if (data.data() && !Gigacage::isCaged(Gigacage::Primitive, data.data()))
Gigacage::disablePrimitiveGigacage();
ArrayBufferContents contents(data, std::nullopt, WTF::move(destructor));
return create(WTF::move(contents));
}
Ref<ArrayBuffer> ArrayBuffer::createShared(Ref<SharedArrayBufferContents>&& shared, bool forceFixedLengthIfWasm)
{
ArrayBufferContents contents(WTF::move(shared), forceFixedLengthIfWasm);
return create(WTF::move(contents));
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreate(size_t numElements, unsigned elementByteSize, std::optional<size_t> maxByteLength)
{
return tryCreate(numElements, elementByteSize, maxByteLength, ArrayBufferContents::InitializationPolicy::ZeroInitialize);
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreate(ArrayBuffer& other)
{
return tryCreate(other.span());
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreate(std::span<const uint8_t> span)
{
ArrayBufferContents contents;
contents.tryAllocate(span.size(), 1, ArrayBufferContents::InitializationPolicy::DontInitialize);
if (!contents.m_data)
return nullptr;
return createInternal(WTF::move(contents), span.data(), span.size());
}
Ref<ArrayBuffer> ArrayBuffer::createUninitialized(size_t numElements, unsigned elementByteSize)
{
return create(numElements, elementByteSize, ArrayBufferContents::InitializationPolicy::DontInitialize);
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreateUninitialized(size_t numElements, unsigned elementByteSize)
{
return tryCreate(numElements, elementByteSize, std::nullopt, ArrayBufferContents::InitializationPolicy::DontInitialize);
}
Ref<ArrayBuffer> ArrayBuffer::create(size_t numElements, unsigned elementByteSize, ArrayBufferContents::InitializationPolicy policy)
{
auto buffer = tryCreate(numElements, elementByteSize, std::nullopt, policy);
if (!buffer)
CRASH();
return buffer.releaseNonNull();
}
Ref<ArrayBuffer> ArrayBuffer::createInternal(ArrayBufferContents&& contents, const void* source, size_t byteLength)
{
auto buffer = adoptRef(*new ArrayBuffer(WTF::move(contents)));
if (byteLength) {
ASSERT(source);
memcpy(buffer->data(), source, byteLength);
}
return buffer;
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreate(size_t numElements, unsigned elementByteSize, std::optional<size_t> maxByteLength, ArrayBufferContents::InitializationPolicy policy)
{
if (!maxByteLength) {
ArrayBufferContents contents;
contents.tryAllocate(numElements, elementByteSize, policy);
if (!contents.m_data)
return nullptr;
return adoptRef(*new ArrayBuffer(WTF::move(contents)));
}
CheckedSize sizeInBytes = numElements;
sizeInBytes *= elementByteSize;
if (sizeInBytes.hasOverflowed() || sizeInBytes.value() > MAX_ARRAY_BUFFER_SIZE)
return nullptr;
if (sizeInBytes.value() > maxByteLength.value() || maxByteLength.value() > MAX_ARRAY_BUFFER_SIZE)
return nullptr;
auto handle = tryAllocateResizableMemory(nullptr, sizeInBytes.value(), maxByteLength.value());
if (!handle)
return nullptr;
void* memory = handle->memory();
ArrayBufferContents contents(memory, sizeInBytes.value(), maxByteLength.value(), handle.releaseNonNull());
return create(WTF::move(contents));
}
ArrayBuffer::ArrayBuffer(ArrayBufferContents&& contents)
: m_contents(WTF::move(contents))
{
}
size_t ArrayBuffer::clampValue(double x, size_t left, size_t right)
{
ASSERT(left <= right);
if (x < left)
x = left;
if (right < x)
x = right;
return x;
}
size_t ArrayBuffer::clampIndex(double index) const
{
size_t currentLength = byteLength();
if (index < 0)
index = currentLength + index;
return clampValue(index, 0, currentLength);
}
RefPtr<ArrayBuffer> ArrayBuffer::slice(double begin, double end) const
{
return sliceWithClampedIndex(clampIndex(begin), clampIndex(end));
}
RefPtr<ArrayBuffer> ArrayBuffer::slice(double begin) const
{
return sliceWithClampedIndex(clampIndex(begin), byteLength());
}
RefPtr<ArrayBuffer> ArrayBuffer::sliceWithClampedIndex(size_t begin, size_t end) const
{
size_t size = begin <= end ? end - begin : 0;
auto result = ArrayBuffer::tryCreate(span().subspan(begin, size));
if (result)
result->setSharingMode(sharingMode());
return result;
}
void ArrayBuffer::makeShared()
{
m_contents.makeShared();
pinAndLock();
ASSERT(!isDetached());
}
void ArrayBuffer::makeWasmMemory()
{
m_isWasmMemory = true;
pinAndLock();
ASSERT(!isDetachable());
}
void ArrayBuffer::refreshAfterWasmMemoryGrow(Wasm::Memory* memory)
{
ASSERT(isWasmMemory());
void* oldData = m_contents.data();
m_contents.refreshAfterWasmMemoryGrow(memory);
void* newData = m_contents.data();
if (newData == oldData)
return;
// JSArrayBufferViews (typed arrays) effectively cache their buffer's data pointer.
for (size_t i = numberOfIncomingReferences(); i--;) {
JSCell* cell = incomingReferenceAt(i);
auto* view = dynamicDowncast<JSArrayBufferView>(cell);
if (view)
view->refreshVector(newData);
}
}
void ArrayBuffer::setSharingMode(ArrayBufferSharingMode newSharingMode)
{
if (newSharingMode == sharingMode())
return;
RELEASE_ASSERT(!isShared()); // Cannot revert sharing.
RELEASE_ASSERT(newSharingMode == ArrayBufferSharingMode::Shared);
makeShared();
}
bool ArrayBuffer::shareWith(ArrayBufferContents& result)
{
if (!m_contents.m_data || !isShared()) {
result.m_data = nullptr;
return false;
}
m_contents.shareWith(result);
return true;
}
bool ArrayBuffer::transferTo(VM& vm, ArrayBufferContents& result)
{
Ref<ArrayBuffer> protect(*this);
if (!m_contents.m_data) {
result.m_data = nullptr;
return false;
}
if (isShared()) {
m_contents.shareWith(result);
return true;
}
if (!isDetachable()) {
m_contents.copyTo(result);
if (!result.m_data)
return false;
return true;
}
result = m_contents.detach();
notifyDetaching(vm);
return true;
}
// We allow detaching wasm memory ArrayBuffers even though they are locked.
void ArrayBuffer::detach(VM& vm)
{
ASSERT(isWasmMemory());
auto unused = m_contents.detach();
notifyDetaching(vm);
}
void ArrayBuffer::notifyDetaching(VM& vm)
{
for (size_t i = numberOfIncomingReferences(); i--;) {
JSCell* cell = incomingReferenceAt(i);
if (JSArrayBufferView* view = dynamicDowncast<JSArrayBufferView>(cell))
view->detachFromArrayBuffer();
}
m_detachingWatchpointSet.fireAll(vm, "Array buffer was detached");
}
// Wasm JS API redefines the abstract operation HostGrowSharedArrayBuffer as follows:
// https://webassembly.github.io/threads/js-api/index.html#abstract-operation-hostgrowsharedarraybuffer
std::expected<int64_t, GrowFailReason> ArrayBuffer::grow(VM& vm, size_t newByteLength)
{
auto shared = m_contents.m_shared;
if (!shared) [[unlikely]]
return makeUnexpected(GrowFailReason::GrowSharedUnavailable);
const bool requirePageMultiple = isWasmMemory();
auto result = shared->grow(vm, newByteLength, requirePageMultiple);
if (result && result.value() > 0)
vm.heap.reportExtraMemoryAllocated(static_cast<JSCell*>(nullptr), result.value());
return result;
}
std::expected<int64_t, GrowFailReason> ArrayBuffer::resize(VM& vm, size_t newByteLength)
{
RELEASE_ASSERT(!isWasmMemory());
auto memoryHandle = m_contents.m_memoryHandle;
if (!memoryHandle || m_contents.m_shared) [[unlikely]]
return makeUnexpected(GrowFailReason::GrowSharedUnavailable);
// A non-shared buffer that is not a Wasm memory owns its handle outright and is reachable only
// from its own agent's thread, so the handle's lock has nothing to guard here.
// Keep in mind that newByteLength may not be page-size-aligned.
if (m_contents.m_maxByteLength < newByteLength)
return makeUnexpected(GrowFailReason::InvalidGrowSize);
int64_t deltaByteLength = static_cast<int64_t>(newByteLength) - static_cast<int64_t>(m_contents.m_sizeInBytes);
if (!deltaByteLength)
return 0;
// A buffer's maxByteLength may exceed the region actually mapped for it, so growth is bounded by
// the mapping.
if (newByteLength > memoryHandle->mappedCapacity())
return makeUnexpected(GrowFailReason::WouldExceedMaximum);
auto newPageCount = PageCount::fromBytesWithRoundUp(newByteLength);
auto oldPageCount = PageCount::fromBytes(memoryHandle->size()); // MemoryHandle's size is always page-size aligned.
if (newPageCount.bytes() > MAX_ARRAY_BUFFER_SIZE)
return makeUnexpected(GrowFailReason::WouldExceedMaximum);
if (newPageCount != oldPageCount) {
ASSERT(memoryHandle->maximum() >= newPageCount);
size_t desiredSize = newPageCount.bytes();
RELEASE_ASSERT(desiredSize <= MAX_ARRAY_BUFFER_SIZE);
if (desiredSize > memoryHandle->size()) {
size_t bytesToAdd = desiredSize - memoryHandle->size();
ASSERT(bytesToAdd);
ASSERT(roundUpToMultipleOf<PageCount::pageSize>(bytesToAdd) == bytesToAdd);
bool allocationSuccess = tryAllocate(&vm,
[&] () -> BufferMemoryResult::Kind {
return BufferMemoryManager::singleton().tryAllocatePhysicalBytes(bytesToAdd);
});
if (!allocationSuccess)
return makeUnexpected(GrowFailReason::OutOfMemory);
void* memory = memoryHandle->memory();
RELEASE_ASSERT(memory);
// Signaling memory must have been pre-allocated virtually.
uint8_t* startAddress = static_cast<uint8_t*>(memory) + memoryHandle->size();
dataLogLnIf(ArrayBufferInternal::verbose, "Marking memory's ", RawPointer(memory), " as read+write in range [", RawPointer(startAddress), ", ", RawPointer(startAddress + bytesToAdd), ")");
if (!BufferMemoryManager::tryMakeReadableAndWritable(startAddress, bytesToAdd)) {
BufferMemoryManager::singleton().freePhysicalBytes(bytesToAdd);
return makeUnexpected(GrowFailReason::OutOfMemory);
}
} else {
size_t bytesToSubtract = memoryHandle->size() - desiredSize;
ASSERT(bytesToSubtract);
ASSERT(roundUpToMultipleOf<PageCount::pageSize>(bytesToSubtract) == bytesToSubtract);
BufferMemoryManager::singleton().freePhysicalBytes(bytesToSubtract);
void* memory = memoryHandle->memory();
RELEASE_ASSERT(memory);
// Signaling memory must have been pre-allocated virtually.
uint8_t* startAddress = static_cast<uint8_t*>(memory) + desiredSize;
dataLogLnIf(ArrayBufferInternal::verbose, "Marking memory's ", RawPointer(memory), " as none in range [", RawPointer(startAddress), ", ", RawPointer(startAddress + bytesToSubtract), ")");
constexpr bool readable = false;
constexpr bool writable = false;
OSAllocator::protect(startAddress, bytesToSubtract, readable, writable);
}
memoryHandle->updateSize(desiredSize);
}
if (m_contents.m_sizeInBytes < newByteLength)
zeroFill(std::bit_cast<uint8_t*>(data()) + m_contents.m_sizeInBytes, newByteLength - m_contents.m_sizeInBytes);
m_contents.m_sizeInBytes = newByteLength;
if (deltaByteLength > 0)
vm.heap.reportExtraMemoryAllocated(static_cast<JSCell*>(nullptr), deltaByteLength);
return deltaByteLength;
}
RefPtr<ArrayBuffer> ArrayBuffer::tryCreateShared(VM& vm, size_t numElements, unsigned elementByteSize, size_t maxByteLength)
{
CheckedSize sizeInBytes = numElements;
sizeInBytes *= elementByteSize;
if (sizeInBytes.hasOverflowed() || sizeInBytes.value() > maxByteLength || maxByteLength > MAX_ARRAY_BUFFER_SIZE)
return nullptr;
auto handle = tryAllocateResizableMemory(&vm, sizeInBytes.value(), maxByteLength);
if (!handle)
return nullptr;
auto* memory = static_cast<uint8_t*>(handle->memory());
return createShared(SharedArrayBufferContents::create({ memory, sizeInBytes.value() }, maxByteLength, WTF::move(handle), nullptr, SharedArrayBufferContents::Mode::Default));
}
ArrayBuffer::~ArrayBuffer() { }
std::expected<int64_t, GrowFailReason> SharedArrayBufferContents::grow(VM& vm, size_t newByteLength, bool requirePageMultiple)
{
if (!m_hasMaxByteLength)
return makeUnexpected(GrowFailReason::GrowSharedUnavailable);
ASSERT(m_memoryHandle);
// Collections happen with the lock released, because asking for one can run finalizers on this
// thread; a retry therefore starts over, since another agent may have grown this buffer meanwhile.
constexpr unsigned maximumAttempts = 2;
for (unsigned attempt = 1; ; ++attempt) {
auto collection = BufferMemoryResult::Kind::Success;
std::expected<int64_t, GrowFailReason> result;
{
Locker locker { m_memoryHandle->lock() };
result = tryGrow(locker, newByteLength, requirePageMultiple, collection);
}
switch (collection) {
case BufferMemoryResult::Kind::Success:
return result;
case BufferMemoryResult::Kind::SuccessAndNotifyMemoryPressure:
vm.heap.collectAsync(CollectionScope::Full);
return result;
case BufferMemoryResult::Kind::SyncTryToReclaimMemory:
if (attempt == maximumAttempts)
return makeUnexpected(GrowFailReason::OutOfMemory);
vm.heap.collectSync(CollectionScope::Full);
break;
}
}
}
std::expected<int64_t, GrowFailReason> SharedArrayBufferContents::tryGrow(const AbstractLocker& locker, size_t newByteLength, bool requirePageMultiple, BufferMemoryResult::Kind& collection)
{
// Keep in mind that newByteLength may not be page-size-aligned. If the buffer is a Wasm memory, that is an error.
size_t sizeInBytes = m_sizeInBytes.load(std::memory_order_seq_cst);
if (sizeInBytes > newByteLength || m_maxByteLength < newByteLength)
return makeUnexpected(GrowFailReason::InvalidGrowSize);
int64_t deltaByteLength = newByteLength - sizeInBytes;
#if ENABLE(WEBASSEMBLY)
if (Options::useWasmMemoryToBufferAPIs()) {
if (requirePageMultiple && deltaByteLength % PageCount::pageSize)
return makeUnexpected(GrowFailReason::InvalidGrowSize);
}
#else
UNUSED_PARAM(requirePageMultiple);
#endif
if (!deltaByteLength)
return 0;
// A buffer's maxByteLength may exceed the region actually mapped for it, so growth is bounded by
// the mapping.
if (newByteLength > m_memoryHandle->mappedCapacity())
return makeUnexpected(GrowFailReason::WouldExceedMaximum);
auto newPageCount = PageCount::fromBytesWithRoundUp(newByteLength);
auto oldPageCount = PageCount::fromBytes(m_memoryHandle->size()); // MemoryHandle's size is always page-size aligned.
if (newPageCount.bytes() > MAX_ARRAY_BUFFER_SIZE)
return makeUnexpected(GrowFailReason::WouldExceedMaximum);
RefPtr memoryHandle = m_memoryHandle;
if (newPageCount != oldPageCount) {
ASSERT(memoryHandle->maximum() >= newPageCount);
size_t desiredSize = newPageCount.bytes();
RELEASE_ASSERT(desiredSize <= MAX_ARRAY_BUFFER_SIZE);
RELEASE_ASSERT(desiredSize > memoryHandle->size());
size_t extraBytes = desiredSize - memoryHandle->size();
RELEASE_ASSERT(extraBytes);
collection = BufferMemoryManager::singleton().tryAllocatePhysicalBytes(extraBytes);
if (collection == BufferMemoryResult::Kind::SyncTryToReclaimMemory)
return makeUnexpected(GrowFailReason::OutOfMemory);
void* memory = memoryHandle->memory();
RELEASE_ASSERT(memory);
// Signaling memory must have been pre-allocated virtually.
uint8_t* startAddress = static_cast<uint8_t*>(memory) + memoryHandle->size();
dataLogLnIf(ArrayBufferInternal::verbose, "Marking memory's ", RawPointer(memory), " as read+write in range [", RawPointer(startAddress), ", ", RawPointer(startAddress + extraBytes), ")");
if (!BufferMemoryManager::tryMakeReadableAndWritable(startAddress, extraBytes)) {
BufferMemoryManager::singleton().freePhysicalBytes(extraBytes);
return makeUnexpected(GrowFailReason::OutOfMemory);
}
memoryHandle->updateSize(desiredSize);
}
zeroFill(std::bit_cast<uint8_t*>(data()) + sizeInBytes, newByteLength - sizeInBytes);
updateSize(newByteLength);
UNUSED_PARAM(locker);
#if ENABLE(WEBASSEMBLY)
// Update cache for instance
for (Ref anchor : memoryHandle->anchors(locker)) {
Locker locker { anchor->m_lock };
if (JSWebAssemblyInstance* instance = anchor->instance())
instance->updateMatchingCachedMemoriesConcurrently(*this);
}
#endif
return deltaByteLength;
}
ASCIILiteral errorMessageForTransfer(ArrayBuffer* buffer)
{
ASSERT(!buffer->isDetachable());
if (buffer->isShared())
return "Cannot transfer a SharedArrayBuffer"_s;
if (buffer->isWasmMemory())
return "Cannot transfer a WebAssembly.Memory"_s;
return "Cannot transfer an ArrayBuffer whose backing store has been accessed by the JavaScriptCore C API"_s;
}
std::optional<ArrayBufferContents> ArrayBufferContents::fromSpan(std::span<const uint8_t> data)
{
void* buffer = Gigacage::tryMalloc(Gigacage::Primitive, data.size_bytes());
if (!buffer)
return std::nullopt;
memcpy(buffer, data.data(), data.size_bytes());
return ArrayBufferContents { buffer, data.size_bytes(), std::nullopt, ArrayBuffer::primitiveGigacageDestructor() };
}
void ArrayBufferContents::refreshAfterWasmMemoryGrow(Wasm::Memory* memory)
{
#if ENABLE(WEBASSEMBLY)
ASSERT(isResizableNonShared());
// If the memory is BoundChecking, the memory's handle is replaced with a different one when it grows.
m_memoryHandle = memory->handle();
m_data = memory->basePointer();
m_sizeInBytes = m_memoryHandle->size();
#else
UNUSED_PARAM(memory);
#endif
}
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END