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cppgc: Add GetWriteBarrierType that ignores slots

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GetWriteBarrierType used to consider the slot so that a barrier is not
triggered for on-stack slots. For strongifying weak collections we want
the write barrier to trigger even if the backing store is only reachable
from stack.

Blink counterpart: crrev.com/c/3162170

Bug: chromium:1244057
Change-Id: I75b1ca62ad5de7bae3d2f4c1a9acce839f3ccdc1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3162127
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76872}
This commit is contained in:
Omer Katz 2021-09-16 13:49:37 +02:00 committed by V8 LUCI CQ
parent b2fa5f335d
commit ed0459770f
2 changed files with 54 additions and 4 deletions
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17
include/cppgc/heap-consistency.h
View File

@ -68,6 +68,23 @@ class HeapConsistency final {
return internal::WriteBarrier::GetWriteBarrierType(slot, params, callback);
}
/**
* Gets the required write barrier type for a specific write.
* This version is meant to be used in conjunction with with a marking write
* barrier barrier which doesn't consider the slot.
*
* \param value The pointer to the object. May be an interior pointer to an
* interface of the actual object.
* \param params Parameters that may be used for actual write barrier calls.
* Only filled if return value indicates that a write barrier is needed. The
* contents of the `params` are an implementation detail.
* \returns whether a write barrier is needed and which barrier to invoke.
*/
static V8_INLINE WriteBarrierType
GetWriteBarrierType(const void* value, WriteBarrierParams& params) {
return internal::WriteBarrier::GetWriteBarrierType(value, params);
}
/**
* Conservative Dijkstra-style write barrier that processes an object if it
* has not yet been processed.

41
include/cppgc/internal/write-barrier.h
View File

@ -67,6 +67,8 @@ class V8_EXPORT WriteBarrier final {
template <typename HeapHandleCallback>
static V8_INLINE Type GetWriteBarrierType(const void* slot, Params& params,
HeapHandleCallback callback);
// Returns the required write barrier for a given `value`.
static V8_INLINE Type GetWriteBarrierType(const void* value, Params& params);
template <typename HeapHandleCallback>
static V8_INLINE Type GetWriteBarrierTypeForExternallyReferencedObject(
@ -148,9 +150,27 @@ class V8_EXPORT WriteBarrierTypeForCagedHeapPolicy final {
return ValueModeDispatch<value_mode>::Get(slot, value, params, callback);
}
template <WriteBarrier::ValueMode value_mode, typename HeapHandleCallback>
static V8_INLINE WriteBarrier::Type Get(const void* value,
WriteBarrier::Params& params,
HeapHandleCallback callback) {
return GetNoSlot(value, params, callback);
}
template <typename HeapHandleCallback>
static V8_INLINE WriteBarrier::Type GetForExternallyReferenced(
const void* value, WriteBarrier::Params& params, HeapHandleCallback) {
const void* value, WriteBarrier::Params& params,
HeapHandleCallback callback) {
return GetNoSlot(value, params, callback);
}
private:
WriteBarrierTypeForCagedHeapPolicy() = delete;
template <typename HeapHandleCallback>
static V8_INLINE WriteBarrier::Type GetNoSlot(const void* value,
WriteBarrier::Params& params,
HeapHandleCallback) {
if (!TryGetCagedHeap(value, value, params)) {
return WriteBarrier::Type::kNone;
}
@ -160,9 +180,6 @@ class V8_EXPORT WriteBarrierTypeForCagedHeapPolicy final {
return SetAndReturnType<WriteBarrier::Type::kNone>(params);
}
private:
WriteBarrierTypeForCagedHeapPolicy() = delete;
template <WriteBarrier::ValueMode value_mode>
struct ValueModeDispatch;
@ -261,6 +278,15 @@ class V8_EXPORT WriteBarrierTypeForNonCagedHeapPolicy final {
return ValueModeDispatch<value_mode>::Get(slot, value, params, callback);
}
template <WriteBarrier::ValueMode value_mode, typename HeapHandleCallback>
static V8_INLINE WriteBarrier::Type Get(const void* value,
WriteBarrier::Params& params,
HeapHandleCallback callback) {
// The slot will never be used in `Get()` below.
return Get<WriteBarrier::ValueMode::kValuePresent>(nullptr, value, params,
callback);
}
template <typename HeapHandleCallback>
static V8_INLINE WriteBarrier::Type GetForExternallyReferenced(
const void* value, WriteBarrier::Params& params,
@ -334,6 +360,13 @@ WriteBarrier::Type WriteBarrier::GetWriteBarrierType(
slot, nullptr, params, callback);
}
// static
WriteBarrier::Type WriteBarrier::GetWriteBarrierType(
const void* value, WriteBarrier::Params& params) {
return WriteBarrierTypePolicy::Get<ValueMode::kValuePresent>(value, params,
[]() {});
}
// static
template <typename HeapHandleCallback>
WriteBarrier::Type