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[GC] Ensure JSFunctions with flushed bytecode are flushed during GC.

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When bytecode is flushed from a SFI, the JSFunctions still retain their
FeedbackVector's and point to the interpreter entry trampoline. They are
reset if re-executed, however if not they could hold onto the feedback
vector indefinetly. This CL adds a pass the GC to detect JSFunctions that
need to be reset, and performs the reset at the end of GC.

BUG=v8:8395

Change-Id: I3de8655aff9ff80f912b4fd51dee43eb98cfd519
Reviewed-on: https://chromium-review.googlesource.com/c/1393292
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58775}
This commit is contained in:
Ross McIlroy 2019-01-14 10:57:31 +00:00 committed by Commit Bot
parent ca4c236fd3
commit f5729f1cda
11 changed files with 95 additions and 39 deletions
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1
src/heap-symbols.h
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@ -383,6 +383,7 @@
TOP_MC_SCOPES(F) \
F(MC_CLEAR_DEPENDENT_CODE) \
F(MC_CLEAR_FLUSHABLE_BYTECODE) \
F(MC_CLEAR_FLUSHED_JS_FUNCTIONS) \
F(MC_CLEAR_MAPS) \
F(MC_CLEAR_SLOTS_BUFFER) \
F(MC_CLEAR_STORE_BUFFER) \

12
src/heap/concurrent-marking.cc
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@ -387,6 +387,17 @@ class ConcurrentMarkingVisitor final
return size;
}
int VisitJSFunction(Map map, JSFunction object) {
int size = VisitJSObjectSubclass(map, object);
// Check if the JSFunction needs reset due to bytecode being flushed.
if (object->NeedsResetDueToFlushedBytecode()) {
weak_objects_->flushed_js_functions.Push(task_id_, object);
}
return size;
}
int VisitMap(Map meta_map, Map map) {
if (!ShouldVisit(map)) return 0;
int size = Map::BodyDescriptor::SizeOf(meta_map, map);
@ -825,6 +836,7 @@ void ConcurrentMarking::Run(int task_id, TaskState* task_state) {
weak_objects_->js_weak_cells.FlushToGlobal(task_id);
weak_objects_->weak_objects_in_code.FlushToGlobal(task_id);
weak_objects_->bytecode_flushing_candidates.FlushToGlobal(task_id);
weak_objects_->flushed_js_functions.FlushToGlobal(task_id);
base::AsAtomicWord::Relaxed_Store<size_t>(&task_state->marked_bytes, 0);
total_marked_bytes_ += marked_bytes;

17
src/heap/mark-compact-inl.h
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@ -93,6 +93,19 @@ int MarkingVisitor<fixed_array_mode, retaining_path_mode, MarkingState>::
return size;
}
template <FixedArrayVisitationMode fixed_array_mode,
TraceRetainingPathMode retaining_path_mode, typename MarkingState>
int MarkingVisitor<fixed_array_mode, retaining_path_mode,
MarkingState>::VisitJSFunction(Map map, JSFunction object) {
int size = Parent::VisitJSFunction(map, object);
// Check if the JSFunction needs reset due to bytecode being flushed.
if (FLAG_flush_bytecode && object->NeedsResetDueToFlushedBytecode()) {
collector_->AddFlushedJSFunction(object);
}
return size;
}
template <FixedArrayVisitationMode fixed_array_mode,
TraceRetainingPathMode retaining_path_mode, typename MarkingState>
int MarkingVisitor<fixed_array_mode, retaining_path_mode,
@ -486,6 +499,10 @@ void MarkCompactCollector::AddBytecodeFlushingCandidate(
weak_objects_.bytecode_flushing_candidates.Push(kMainThread, flush_candidate);
}
void MarkCompactCollector::AddFlushedJSFunction(JSFunction flushed_function) {
weak_objects_.flushed_js_functions.Push(kMainThread, flushed_function);
}
template <LiveObjectIterationMode mode>
LiveObjectRange<mode>::iterator::iterator(MemoryChunk* chunk, Bitmap* bitmap,
Address start)

16
src/heap/mark-compact.cc
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@ -1906,6 +1906,11 @@ void MarkCompactCollector::ClearNonLiveReferences() {
ClearOldBytecodeCandidates();
}
{
TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_CLEAR_FLUSHED_JS_FUNCTIONS);
ClearFlushedJsFunctions();
}
{
TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_CLEAR_WEAK_LISTS);
// Process the weak references.
@ -1935,6 +1940,7 @@ void MarkCompactCollector::ClearNonLiveReferences() {
DCHECK(weak_objects_.js_weak_refs.IsEmpty());
DCHECK(weak_objects_.js_weak_cells.IsEmpty());
DCHECK(weak_objects_.bytecode_flushing_candidates.IsEmpty());
DCHECK(weak_objects_.flushed_js_functions.IsEmpty());
}
void MarkCompactCollector::MarkDependentCodeForDeoptimization() {
@ -2073,6 +2079,15 @@ void MarkCompactCollector::ClearOldBytecodeCandidates() {
}
}
void MarkCompactCollector::ClearFlushedJsFunctions() {
DCHECK(FLAG_flush_bytecode || weak_objects_.flushed_js_functions.IsEmpty());
JSFunction flushed_js_function;
while (weak_objects_.flushed_js_functions.Pop(kMainThread,
&flushed_js_function)) {
flushed_js_function->ResetIfBytecodeFlushed();
}
}
void MarkCompactCollector::ClearFullMapTransitions() {
TransitionArray array;
while (weak_objects_.transition_arrays.Pop(kMainThread, &array)) {
@ -2330,6 +2345,7 @@ void MarkCompactCollector::AbortWeakObjects() {
weak_objects_.js_weak_refs.Clear();
weak_objects_.js_weak_cells.Clear();
weak_objects_.bytecode_flushing_candidates.Clear();
weak_objects_.flushed_js_functions.Clear();
}
bool MarkCompactCollector::IsOnEvacuationCandidate(MaybeObject obj) {

6
src/heap/mark-compact.h
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@ -449,6 +449,7 @@ struct WeakObjects {
Worklist<JSWeakCell, 64> js_weak_cells;
Worklist<SharedFunctionInfo, 64> bytecode_flushing_candidates;
Worklist<JSFunction, 64> flushed_js_functions;
};
struct EphemeronMarking {
@ -662,6 +663,7 @@ class MarkCompactCollector final : public MarkCompactCollectorBase {
}
inline void AddBytecodeFlushingCandidate(SharedFunctionInfo flush_candidate);
inline void AddFlushedJSFunction(JSFunction flushed_function);
void AddNewlyDiscovered(HeapObject object) {
if (ephemeron_marking_.newly_discovered_overflowed) return;
@ -793,6 +795,9 @@ class MarkCompactCollector final : public MarkCompactCollectorBase {
// collections.
void ClearOldBytecodeCandidates();
// Resets any JSFunctions which have had their bytecode flushed.
void ClearFlushedJsFunctions();
// Compact every array in the global list of transition arrays and
// trim the corresponding descriptor array if a transition target is non-live.
void ClearFullMapTransitions();
@ -927,6 +932,7 @@ class MarkingVisitor final
V8_INLINE int VisitFixedArray(Map map, FixedArray object);
V8_INLINE int VisitJSApiObject(Map map, JSObject object);
V8_INLINE int VisitJSArrayBuffer(Map map, JSArrayBuffer object);
V8_INLINE int VisitJSFunction(Map map, JSFunction object);
V8_INLINE int VisitJSDataView(Map map, JSDataView object);
V8_INLINE int VisitJSTypedArray(Map map, JSTypedArray object);
V8_INLINE int VisitMap(Map map, Map object);

1
src/heap/objects-visiting.h
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@ -55,6 +55,7 @@ class WasmInstanceObject;
V(FixedTypedArrayBase, FixedTypedArrayBase) \
V(JSArrayBuffer, JSArrayBuffer) \
V(JSDataView, JSDataView) \
V(JSFunction, JSFunction) \
V(JSObject, JSObject) \
V(JSTypedArray, JSTypedArray) \
V(JSWeakCell, JSWeakCell) \

24
src/objects-body-descriptors-inl.h
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@ -197,30 +197,6 @@ class JSObject::FastBodyDescriptor final : public BodyDescriptorBase {
}
};
class JSFunction::BodyDescriptor final : public BodyDescriptorBase {
public:
static bool IsValidSlot(Map map, HeapObject obj, int offset) {
if (offset < kSizeWithoutPrototype) return true;
if (offset < kSizeWithPrototype && map->has_prototype_slot()) {
return true;
}
return IsValidJSObjectSlotImpl(map, obj, offset);
}
template <typename ObjectVisitor>
static inline void IterateBody(Map map, HeapObject obj, int object_size,
ObjectVisitor* v) {
int header_size = JSFunction::GetHeaderSize(map->has_prototype_slot());
DCHECK_EQ(header_size, JSObject::GetHeaderSize(map));
IteratePointers(obj, kPropertiesOrHashOffset, header_size, v);
IterateJSObjectBodyImpl(map, obj, header_size, object_size, v);
}
static inline int SizeOf(Map map, HeapObject object) {
return map->instance_size();
}
};
class JSWeakCell::BodyDescriptor final : public BodyDescriptorBase {
public:
static bool IsValidSlot(Map map, HeapObject obj, int offset) {

4
src/objects.cc
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@ -3214,6 +3214,9 @@ VisitorId Map::GetVisitorId(Map map) {
case JS_DATA_VIEW_TYPE:
return kVisitJSDataView;
case JS_FUNCTION_TYPE:
return kVisitJSFunction;
case JS_TYPED_ARRAY_TYPE:
return kVisitJSTypedArray;
@ -3254,7 +3257,6 @@ VisitorId Map::GetVisitorId(Map map) {
case JS_DATE_TYPE:
case JS_ARRAY_ITERATOR_TYPE:
case JS_ARRAY_TYPE:
case JS_FUNCTION_TYPE:
case JS_GLOBAL_PROXY_TYPE:
case JS_GLOBAL_OBJECT_TYPE:
case JS_MESSAGE_OBJECT_TYPE:

49
src/objects/js-objects-inl.h
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@ -459,7 +459,6 @@ ACCESSORS(JSBoundFunction, bound_target_function, JSReceiver,
ACCESSORS(JSBoundFunction, bound_this, Object, kBoundThisOffset)
ACCESSORS(JSBoundFunction, bound_arguments, FixedArray, kBoundArgumentsOffset)
ACCESSORS(JSFunction, shared, SharedFunctionInfo, kSharedFunctionInfoOffset)
ACCESSORS(JSFunction, raw_feedback_cell, FeedbackCell, kFeedbackCellOffset)
ACCESSORS(JSGlobalObject, native_context, Context, kNativeContextOffset)
@ -542,18 +541,29 @@ AbstractCode JSFunction::abstract_code() {
}
Code JSFunction::code() const {
return Code::cast(READ_FIELD(*this, kCodeOffset));
return Code::cast(RELAXED_READ_FIELD(*this, kCodeOffset));
}
void JSFunction::set_code(Code value) {
DCHECK(!Heap::InNewSpace(value));
WRITE_FIELD(*this, kCodeOffset, value);
RELAXED_WRITE_FIELD(*this, kCodeOffset, value);
MarkingBarrier(*this, RawField(kCodeOffset), value);
}
void JSFunction::set_code_no_write_barrier(Code value) {
DCHECK(!Heap::InNewSpace(value));
WRITE_FIELD(*this, kCodeOffset, value);
RELAXED_WRITE_FIELD(*this, kCodeOffset, value);
}
SharedFunctionInfo JSFunction::shared() const {
return SharedFunctionInfo::cast(
RELAXED_READ_FIELD(*this, kSharedFunctionInfoOffset));
}
void JSFunction::set_shared(SharedFunctionInfo value, WriteBarrierMode mode) {
// Release semantics to support acquire read in NeedsResetDueToFlushedBytecode
RELEASE_WRITE_FIELD(*this, kSharedFunctionInfoOffset, value);
CONDITIONAL_WRITE_BARRIER(*this, kSharedFunctionInfoOffset, value, mode);
}
void JSFunction::ClearOptimizedCodeSlot(const char* reason) {
@ -659,17 +669,32 @@ bool JSFunction::is_compiled() const {
shared()->is_compiled();
}
bool JSFunction::NeedsResetDueToFlushedBytecode() {
if (!FLAG_flush_bytecode) return false;
// Do a raw read for shared and code fields here since this function may be
// called on a concurrent thread and the JSFunction might not be fully
// initialized yet.
Object maybe_shared = ACQUIRE_READ_FIELD(*this, kSharedFunctionInfoOffset);
Object maybe_code = RELAXED_READ_FIELD(*this, kCodeOffset);
if (!maybe_shared->IsSharedFunctionInfo() || !maybe_code->IsCode()) {
return false;
}
SharedFunctionInfo shared = SharedFunctionInfo::cast(maybe_shared);
Code code = Code::cast(maybe_code);
return !shared->is_compiled() &&
code->builtin_index() != Builtins::kCompileLazy;
}
void JSFunction::ResetIfBytecodeFlushed() {
if (!shared()->is_compiled()) {
if (NeedsResetDueToFlushedBytecode()) {
// Bytecode was flushed and function is now uncompiled, reset JSFunction
// by setting code to CompileLazy and clearing the feedback vector.
if (code()->builtin_index() != Builtins::kCompileLazy) {
set_code(GetIsolate()->builtins()->builtin(i::Builtins::kCompileLazy));
}
if (raw_feedback_cell()->value()->IsFeedbackVector()) {
raw_feedback_cell()->set_value(
ReadOnlyRoots(GetIsolate()).undefined_value());
}
set_code(GetIsolate()->builtins()->builtin(i::Builtins::kCompileLazy));
raw_feedback_cell()->set_value(
ReadOnlyRoots(GetIsolate()).undefined_value());
}
}

3
src/objects/js-objects.h
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@ -1042,6 +1042,7 @@ class JSFunction : public JSObject {
void ClearTypeFeedbackInfo();
// Resets function to clear compiled data after bytecode has been flushed.
inline bool NeedsResetDueToFlushedBytecode();
inline void ResetIfBytecodeFlushed();
inline bool has_prototype_slot() const;
@ -1097,8 +1098,6 @@ class JSFunction : public JSObject {
int* instance_size,
int* in_object_properties);
class BodyDescriptor;
// Dispatched behavior.
DECL_PRINTER(JSFunction)
DECL_VERIFIER(JSFunction)

1
src/objects/map.h
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@ -43,6 +43,7 @@ enum InstanceType : uint16_t;
V(JSApiObject) \
V(JSArrayBuffer) \
V(JSDataView) \
V(JSFunction) \
V(JSObject) \
V(JSObjectFast) \
V(JSTypedArray) \