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 
10 namespace cppgc {
11 namespace internal {
12 
GetTraceDescriptor( const void* address)13 TraceDescriptor 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