src: fix AliasedBuffer memory attribution in heap snapshots

node.gyp

@@ -571,6 +571,7 @@
         'src/uv.cc',
         # headers to make for a more pleasant IDE experience
         'src/aliased_buffer.h',
+        'src/aliased_buffer-inl.h',
         'src/aliased_struct.h',
         'src/aliased_struct-inl.h',
         'src/async_wrap.h',

src/aliased_buffer-inl.h

@@ -0,0 +1,232 @@
+#ifndef SRC_ALIASED_BUFFER_INL_H_
+#define SRC_ALIASED_BUFFER_INL_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "aliased_buffer.h"
+#include "util-inl.h"
+
+namespace node {
+
+typedef size_t AliasedBufferIndex;
+
+template <typename NativeT, typename V8T>
+AliasedBufferBase<NativeT, V8T>::AliasedBufferBase(
+    v8::Isolate* isolate, const size_t count, const AliasedBufferIndex* index)
+    : isolate_(isolate), count_(count), byte_offset_(0), index_(index) {
+  CHECK_GT(count, 0);
+  if (index != nullptr) {
+    // Will be deserialized later.
+    return;
+  }
+  const v8::HandleScope handle_scope(isolate_);
+  const size_t size_in_bytes =
+      MultiplyWithOverflowCheck(sizeof(NativeT), count);
+
+  // allocate v8 ArrayBuffer
+  v8::Local<v8::ArrayBuffer> ab = v8::ArrayBuffer::New(isolate_, size_in_bytes);
+  buffer_ = static_cast<NativeT*>(ab->Data());
+
+  // allocate v8 TypedArray
+  v8::Local<V8T> js_array = V8T::New(ab, byte_offset_, count);
+  js_array_ = v8::Global<V8T>(isolate, js_array);
+}
+
+template <typename NativeT, typename V8T>
+AliasedBufferBase<NativeT, V8T>::AliasedBufferBase(
+    v8::Isolate* isolate,
+    const size_t byte_offset,
+    const size_t count,
+    const AliasedBufferBase<uint8_t, v8::Uint8Array>& backing_buffer,
+    const AliasedBufferIndex* index)
+    : isolate_(isolate),
+      count_(count),
+      byte_offset_(byte_offset),
+      index_(index) {
+  if (index != nullptr) {
+    // Will be deserialized later.
+    return;
+  }
+  const v8::HandleScope handle_scope(isolate_);
+  v8::Local<v8::ArrayBuffer> ab = backing_buffer.GetArrayBuffer();
+
+  // validate that the byte_offset is aligned with sizeof(NativeT)
+  CHECK_EQ(byte_offset & (sizeof(NativeT) - 1), 0);
+  // validate this fits inside the backing buffer
+  CHECK_LE(MultiplyWithOverflowCheck(sizeof(NativeT), count),
+           ab->ByteLength() - byte_offset);
+
+  buffer_ = reinterpret_cast<NativeT*>(
+      const_cast<uint8_t*>(backing_buffer.GetNativeBuffer() + byte_offset));
+
+  v8::Local<V8T> js_array = V8T::New(ab, byte_offset, count);
+  js_array_ = v8::Global<V8T>(isolate, js_array);
+}
+
+template <typename NativeT, typename V8T>
+AliasedBufferBase<NativeT, V8T>::AliasedBufferBase(
+    const AliasedBufferBase& that)
+    : isolate_(that.isolate_),
+      count_(that.count_),
+      byte_offset_(that.byte_offset_),
+      buffer_(that.buffer_) {
+  DCHECK_NULL(index_);
+  js_array_ = v8::Global<V8T>(that.isolate_, that.GetJSArray());
+}
+
+template <typename NativeT, typename V8T>
+AliasedBufferIndex AliasedBufferBase<NativeT, V8T>::Serialize(
+    v8::Local<v8::Context> context, v8::SnapshotCreator* creator) {
+  DCHECK_NULL(index_);
+  return creator->AddData(context, GetJSArray());
+}
+
+template <typename NativeT, typename V8T>
+inline void AliasedBufferBase<NativeT, V8T>::Deserialize(
+    v8::Local<v8::Context> context) {
+  DCHECK_NOT_NULL(index_);
+  v8::Local<V8T> arr =
+      context->GetDataFromSnapshotOnce<V8T>(*index_).ToLocalChecked();
+  // These may not hold true for AliasedBuffers that have grown, so should
+  // be removed when we expand the snapshot support.
+  DCHECK_EQ(count_, arr->Length());
+  DCHECK_EQ(byte_offset_, arr->ByteOffset());
+  uint8_t* raw = static_cast<uint8_t*>(arr->Buffer()->Data());
+  buffer_ = reinterpret_cast<NativeT*>(raw + byte_offset_);
+  js_array_.Reset(isolate_, arr);
+  index_ = nullptr;
+}
+
+template <typename NativeT, typename V8T>
+AliasedBufferBase<NativeT, V8T>& AliasedBufferBase<NativeT, V8T>::operator=(
+    AliasedBufferBase<NativeT, V8T>&& that) noexcept {
+  DCHECK_NULL(index_);
+  this->~AliasedBufferBase();
+  isolate_ = that.isolate_;
+  count_ = that.count_;
+  byte_offset_ = that.byte_offset_;
+  buffer_ = that.buffer_;
+
+  js_array_.Reset(isolate_, that.js_array_.Get(isolate_));
+
+  that.buffer_ = nullptr;
+  that.js_array_.Reset();
+  return *this;
+}
+
+template <typename NativeT, typename V8T>
+v8::Local<V8T> AliasedBufferBase<NativeT, V8T>::GetJSArray() const {
+  DCHECK_NULL(index_);
+  return js_array_.Get(isolate_);
+}
+
+template <typename NativeT, typename V8T>
+void AliasedBufferBase<NativeT, V8T>::Release() {
+  DCHECK_NULL(index_);
+  js_array_.Reset();
+}
+
+template <typename NativeT, typename V8T>
+v8::Local<v8::ArrayBuffer> AliasedBufferBase<NativeT, V8T>::GetArrayBuffer()
+    const {
+  return GetJSArray()->Buffer();
+}
+
+template <typename NativeT, typename V8T>
+inline const NativeT* AliasedBufferBase<NativeT, V8T>::GetNativeBuffer() const {
+  DCHECK_NULL(index_);
+  return buffer_;
+}
+
+template <typename NativeT, typename V8T>
+inline const NativeT* AliasedBufferBase<NativeT, V8T>::operator*() const {
+  return GetNativeBuffer();
+}
+
+template <typename NativeT, typename V8T>
+inline void AliasedBufferBase<NativeT, V8T>::SetValue(const size_t index,
+                                                      NativeT value) {
+  DCHECK_LT(index, count_);
+  DCHECK_NULL(index_);
+  buffer_[index] = value;
+}
+
+template <typename NativeT, typename V8T>
+inline const NativeT AliasedBufferBase<NativeT, V8T>::GetValue(
+    const size_t index) const {
+  DCHECK_NULL(index_);
+  DCHECK_LT(index, count_);
+  return buffer_[index];
+}
+
+template <typename NativeT, typename V8T>
+typename AliasedBufferBase<NativeT, V8T>::Reference
+AliasedBufferBase<NativeT, V8T>::operator[](size_t index) {
+  DCHECK_NULL(index_);
+  return Reference(this, index);
+}
+
+template <typename NativeT, typename V8T>
+NativeT AliasedBufferBase<NativeT, V8T>::operator[](size_t index) const {
+  return GetValue(index);
+}
+
+template <typename NativeT, typename V8T>
+size_t AliasedBufferBase<NativeT, V8T>::Length() const {
+  return count_;
+}
+
+template <typename NativeT, typename V8T>
+void AliasedBufferBase<NativeT, V8T>::reserve(size_t new_capacity) {
+  DCHECK_NULL(index_);
+  DCHECK_GE(new_capacity, count_);
+  DCHECK_EQ(byte_offset_, 0);
+  const v8::HandleScope handle_scope(isolate_);
+
+  const size_t old_size_in_bytes = sizeof(NativeT) * count_;
+  const size_t new_size_in_bytes =
+      MultiplyWithOverflowCheck(sizeof(NativeT), new_capacity);
+
+  // allocate v8 new ArrayBuffer
+  v8::Local<v8::ArrayBuffer> ab =
+      v8::ArrayBuffer::New(isolate_, new_size_in_bytes);
+
+  // allocate new native buffer
+  NativeT* new_buffer = static_cast<NativeT*>(ab->Data());
+  // copy old content
+  memcpy(new_buffer, buffer_, old_size_in_bytes);
+
+  // allocate v8 TypedArray
+  v8::Local<V8T> js_array = V8T::New(ab, byte_offset_, new_capacity);
+
+  // move over old v8 TypedArray
+  js_array_ = std::move(v8::Global<V8T>(isolate_, js_array));
+
+  buffer_ = new_buffer;
+  count_ = new_capacity;
+}
+
+template <typename NativeT, typename V8T>
+inline size_t AliasedBufferBase<NativeT, V8T>::SelfSize() const {
+  return sizeof(*this);
+}
+
+#define VM(NativeT, V8T)                                                       \
+  template <>                                                                  \
+  inline const char* AliasedBufferBase<NativeT, v8::V8T>::MemoryInfoName()     \
+      const {                                                                  \
+    return "Aliased" #V8T;                                                     \
+  }                                                                            \
+  template <>                                                                  \
+  inline void AliasedBufferBase<NativeT, v8::V8T>::MemoryInfo(                 \
+      node::MemoryTracker* tracker) const {                                    \
+    tracker->TrackField("js_array", js_array_);                                \
+  }
+ALIASED_BUFFER_LIST(VM)
+#undef VM
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_ALIASED_BUFFER_INL_H_