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Revert "[api, global-handles] Fix moving weak Global<T>"

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This reverts commit 584f0b43b2.

Reason for revert: Breaks MSAN build - https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/24872

Original change's description:
> [api, global-handles] Fix moving weak Global<T>
> 
> v8::Global may be used as a weak reference. In the case this reference is a
> simple phantom reference, we need to update the internal state to be able to
> clear the right slot once the object refered to is dead.
> 
> Bug: chromium:924220
> Change-Id: I2ab7c3afcbe22988791faef406c284db03a43caf
> Reviewed-on: https://chromium-review.googlesource.com/c/1430101
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#59040}

TBR=ulan@chromium.org,mlippautz@chromium.org

Change-Id: I19c3e929962203df4e1f24191d054180723b1c9d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:924220
Reviewed-on: https://chromium-review.googlesource.com/c/1430833
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59046}
This commit is contained in:
Maya Lekova 2019-01-23 17:06:50 +00:00 committed by Commit Bot
parent bd019bdb72
commit 18f32ca89c
5 changed files with 18 additions and 99 deletions
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55
include/v8.h
View File

@ -758,7 +758,6 @@ class Global : public PersistentBase<T> {
* A Global with no storage cell.
*/
V8_INLINE Global() : PersistentBase<T>(nullptr) {}
/**
* Construct a Global from a Local.
* When the Local is non-empty, a new storage cell is created
@ -769,7 +768,6 @@ class Global : public PersistentBase<T> {
: PersistentBase<T>(PersistentBase<T>::New(isolate, *that)) {
TYPE_CHECK(T, S);
}
/**
* Construct a Global from a PersistentBase.
* When the Persistent is non-empty, a new storage cell is created
@ -780,20 +778,26 @@ class Global : public PersistentBase<T> {
: PersistentBase<T>(PersistentBase<T>::New(isolate, that.val_)) {
TYPE_CHECK(T, S);
}
/**
* Move constructor.
*/
V8_INLINE Global(Global&& other);
V8_INLINE Global(Global&& other) : PersistentBase<T>(other.val_) {
other.val_ = nullptr;
}
V8_INLINE ~Global() { this->Reset(); }
/**
* Move via assignment.
*/
template <class S>
V8_INLINE Global& operator=(Global<S>&& rhs);
V8_INLINE Global& operator=(Global<S>&& rhs) { // NOLINT
TYPE_CHECK(T, S);
if (this != &rhs) {
this->Reset();
this->val_ = rhs.val_;
rhs.val_ = nullptr;
}
return *this;
}
/**
* Pass allows returning uniques from functions, etc.
*/
@ -818,6 +822,7 @@ class Global : public PersistentBase<T> {
template <class T>
using UniquePersistent = Global<T>;
/**
* A stack-allocated class that governs a number of local handles.
* After a handle scope has been created, all local handles will be
@ -8560,9 +8565,7 @@ class V8_EXPORT V8 {
static internal::Address* GlobalizeReference(internal::Isolate* isolate,
internal::Address* handle);
static void MoveGlobalReference(internal::Address** from,
internal::Address** to);
static internal::Address* CopyGlobalReference(internal::Address* from);
static internal::Address* CopyPersistent(internal::Address* handle);
static void DisposeGlobal(internal::Address* global_handle);
static void MakeWeak(internal::Address* location, void* data,
WeakCallbackInfo<void>::Callback weak_callback,
@ -8582,8 +8585,6 @@ class V8_EXPORT V8 {
static void FromJustIsNothing();
static void ToLocalEmpty();
static void InternalFieldOutOfBounds(int index);
template <class T>
friend class Global;
template <class T> friend class Local;
template <class T>
friend class MaybeLocal;
@ -9511,7 +9512,7 @@ void Persistent<T, M>::Copy(const Persistent<S, M2>& that) {
this->Reset();
if (that.IsEmpty()) return;
internal::Address* p = reinterpret_cast<internal::Address*>(that.val_);
this->val_ = reinterpret_cast<T*>(V8::CopyGlobalReference(p));
this->val_ = reinterpret_cast<T*>(V8::CopyPersistent(p));
M::Copy(that, this);
}
@ -9644,32 +9645,6 @@ uint16_t PersistentBase<T>::WrapperClassId() const {
return *reinterpret_cast<uint16_t*>(addr);
}
template <class T>
Global<T>::Global(Global&& other) : PersistentBase<T>(other.val_) {
if (other.val_ != nullptr) {
V8::MoveGlobalReference(reinterpret_cast<internal::Address**>(&other.val_),
reinterpret_cast<internal::Address**>(&this->val_));
other.val_ = nullptr;
}
}
template <class T>
template <class S>
Global<T>& Global<T>::operator=(Global<S>&& rhs) {
TYPE_CHECK(T, S);
if (this != &rhs) {
this->Reset();
if (rhs.val_ != nullptr) {
this->val_ = rhs.val_;
V8::MoveGlobalReference(
reinterpret_cast<internal::Address**>(&rhs.val_),
reinterpret_cast<internal::Address**>(&this->val_));
rhs.val_ = nullptr;
}
}
return *this;
}
template <typename T>
ReturnValue<T>::ReturnValue(internal::Address* slot) : value_(slot) {}

8
src/api.cc
View File

@ -1012,15 +1012,11 @@ i::Address* V8::GlobalizeReference(i::Isolate* isolate, i::Address* obj) {
return result.location();
}
i::Address* V8::CopyGlobalReference(i::Address* from) {
i::Handle<i::Object> result = i::GlobalHandles::CopyGlobal(from);
i::Address* V8::CopyPersistent(i::Address* obj) {
i::Handle<i::Object> result = i::GlobalHandles::CopyGlobal(obj);
return result.location();
}
void V8::MoveGlobalReference(internal::Address** from, internal::Address** to) {
i::GlobalHandles::MoveGlobal(from, to);
}
void V8::RegisterExternallyReferencedObject(i::Address* location,
i::Isolate* isolate) {
isolate->heap()->RegisterExternallyReferencedObject(location);

14
src/global-handles.cc
View File

@ -625,20 +625,6 @@ Handle<Object> GlobalHandles::CopyGlobal(Address* location) {
return global_handles->Create(*location);
}
void GlobalHandles::MoveGlobal(Address** from, Address** to) {
DCHECK_NOT_NULL(*from);
DCHECK_NOT_NULL(*to);
DCHECK_EQ(*from, *to);
Node* node = Node::FromLocation(*from);
if (node->IsPhantomResetHandle()) {
node->set_parameter(to);
}
// - Strong handles do not require fixups.
// - Weak handles with finalizers and callbacks are too general to fix up. For
// those the callers need to ensure consistency.
}
void GlobalHandles::Destroy(Address* location) {
if (location != nullptr) {
NodeSpace<Node>::Release(Node::FromLocation(location));

5
src/global-handles.h
View File

@ -40,10 +40,7 @@ enum WeaknessType {
// callbacks and finalizers attached to them.
class GlobalHandles final {
public:
// Move a global handle.
static void MoveGlobal(Address** from, Address** to);
// Copy a global handle.
// Copy a global handle
static Handle<Object> CopyGlobal(Address* location);
// Destroy a global handle.

35
test/cctest/test-global-handles.cc
View File

@ -69,14 +69,6 @@ void ConstructJSObject(v8::Isolate* isolate, v8::Local<v8::Context> context,
CHECK(!flag_and_persistent->handle.IsEmpty());
}
void ConstructJSObject(v8::Isolate* isolate, v8::Global<v8::Object>* global) {
v8::HandleScope scope(isolate);
v8::Local<v8::Object> object(v8::Object::New(isolate));
CHECK(!object.IsEmpty());
*global = v8::Global<v8::Object>(isolate, object);
CHECK(!global->IsEmpty());
}
void ConstructJSApiObject(v8::Isolate* isolate, v8::Local<v8::Context> context,
FlagAndPersistent* flag_and_persistent) {
v8::HandleScope handle_scope(isolate);
@ -540,32 +532,5 @@ TEST(SecondPassPhantomCallbacks) {
CHECK(fp.flag);
}
TEST(MoveStrongGlobal) {
CcTest::InitializeVM();
v8::Isolate* isolate = CcTest::isolate();
v8::HandleScope scope(isolate);
v8::Global<v8::Object>* global = new Global<v8::Object>();
ConstructJSObject(isolate, global);
InvokeMarkSweep();
v8::Global<v8::Object> global2(std::move(*global));
delete global;
InvokeMarkSweep();
}
TEST(MoveWeakGlobal) {
CcTest::InitializeVM();
v8::Isolate* isolate = CcTest::isolate();
v8::HandleScope scope(isolate);
v8::Global<v8::Object>* global = new Global<v8::Object>();
ConstructJSObject(isolate, global);
InvokeMarkSweep();
global->SetWeak();
v8::Global<v8::Object> global2(std::move(*global));
delete global;
InvokeMarkSweep();
}
} // namespace internal
} // namespace v8