1// Copyright 2020 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "include/cppgc/trace-trait.h"
6
7#include "src/heap/cppgc/gc-info-table.h"
8#include "src/heap/cppgc/heap-page.h"
9
10namespace cppgc {
11namespace internal {
12
13TraceDescriptor TraceTraitFromInnerAddressImpl::GetTraceDescriptor(
14    const void* address) {
15  // address is guaranteed to be on a normal page because this is used only for
16  // mixins.
17  const BasePage* page = BasePage::FromPayload(address);
18  page->SynchronizedLoad();
19  const HeapObjectHeader& header =
20      page->ObjectHeaderFromInnerAddress<AccessMode::kAtomic>(address);
21  return {header.ObjectStart(),
22          GlobalGCInfoTable::GCInfoFromIndex(
23              header.GetGCInfoIndex<AccessMode::kAtomic>())
24              .trace};
25}
26
27}  // namespace internal
28}  // namespace cppgc
29