5611f70b3d
This is a reland of bc33f5aeba
Contributed by titzer@chromium.org
Original change's description:
> [arraybuffer] Rearchitect backing store ownership
>
> This CL completely rearchitects the ownership of array buffer backing stores,
> consolidating ownership into a {BackingStore} C++ object that is tracked
> throughout V8 using unique_ptr and shared_ptr where appropriate.
>
> Overall, lifetime management is simpler and more explicit. The numerous
> ways that array buffers were initialized have been streamlined to one
> Attach() method on JSArrayBuffer. The array buffer tracker in the
> GC implementation now manages std::shared_ptr<BackingStore> pointers,
> and the construction and destruction of the BackingStore object itself
> handles the underlying page or embedder-allocated memory.
>
> The embedder API remains unchanged for now. We use the
> v8::ArrayBuffer::Contents struct to hide an additional shared_ptr to
> keep the backing store alive properly, even in the case of aliases
> from live heap objects. Thus the embedder has a lower chance of making
> a mistake. Long-term, we should move the embedder to a model where they
> manage backing stores using shared_ptr to an opaque backing store object.
TBR=yangguo@chromium.org
BUG=v8:9380,v8:9221,chromium:986318
Change-Id: If671a4a9ca0476e8f084efae46e0d2bf99ed99ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1731005
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63041}
35 lines
1.0 KiB
C++
35 lines
1.0 KiB
C++
// Copyright 2019 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef V8_CCTEST_MANUALLY_EXTERNALIZED_BUFFER_H_
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#define V8_CCTEST_MANUALLY_EXTERNALIZED_BUFFER_H_
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#include "src/api/api-inl.h"
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namespace v8 {
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namespace internal {
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namespace testing {
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// Utility to free the allocated memory for a buffer that is manually
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// externalized in a test.
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struct ManuallyExternalizedBuffer {
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Handle<JSArrayBuffer> buffer_;
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v8::ArrayBuffer::Contents contents_;
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explicit ManuallyExternalizedBuffer(Handle<JSArrayBuffer> buffer)
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: buffer_(buffer),
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contents_(v8::Utils::ToLocal(buffer_)->Externalize()) {}
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~ManuallyExternalizedBuffer() {
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contents_.Deleter()(contents_.Data(), contents_.ByteLength(),
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contents_.DeleterData());
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}
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void* backing_store() { return contents_.Data(); }
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};
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} // namespace testing
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} // namespace internal
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} // namespace v8
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#endif // V8_CCTEST_MANUALLY_EXTERNALIZED_BUFFER_H_
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