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[vm] Finer labeling of roots in heap snapshots.

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Add missing object id zone roots, which should have been part of ffbbdb5a10 when they switched from weak to strong.

TEST=examine snapshot after using inspect
Bug: https://github.com/dart-lang/sdk/issues/61036
Change-Id: I3bea765e4ae487babfd86eccbaa87bab80320dcf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/439160
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
This commit is contained in:
Ryan Macnak
2025-07-07 17:02:17 -07:00
committed by Commit Queue
parent cc5f351c34
commit d8117e1b08
13 changed files with 193 additions and 130 deletions
Download Patch File Download Diff File Expand all files Collapse all files
runtime/vm/heap/become.cc
-9
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@@ -365,15 +365,6 @@ void Become::FollowForwardingPointers(Thread* thread) {
// C++ pointers.
isolate_group->VisitObjectPointers(&pointer_visitor,
ValidationPolicy::kValidateFrames);
#ifndef PRODUCT
isolate_group->ForEachIsolate(
[&](Isolate* isolate) {
for (intptr_t i = 0; i < isolate->NumServiceIdZones(); ++i) {
isolate->GetServiceIdZone(i)->VisitPointers(pointer_visitor);
}
},
/*at_safepoint=*/true);
#endif // !PRODUCT
// Weak persistent handles.
ForwardHeapPointersHandleVisitor handle_visitor;
runtime/vm/heap/compactor.cc
-13
View File
@@ -469,19 +469,6 @@ void CompactorTask::RunEnteredIsolateGroup() {
isolate_group_->VisitWeakPersistentHandles(compactor_);
break;
}
#ifndef PRODUCT
case 4: {
TIMELINE_FUNCTION_GC_DURATION(thread, "ForwardObjectIdRing");
isolate_group_->ForEachIsolate(
[&](Isolate* isolate) {
for (intptr_t i = 0; i < isolate->NumServiceIdZones(); ++i) {
isolate->GetServiceIdZone(i)->VisitPointers(*compactor_);
}
},
/*at_safepoint=*/true);
break;
}
#endif // !PRODUCT
default:
more_forwarding_tasks = false;
}
runtime/vm/heap/incremental_compactor.cc
-13
View File
@@ -574,7 +574,6 @@ class EpilogueState {
bool TakeOOM() { return oom_slice_.exchange(false); }
bool TakeWeakHandles() { return weak_handles_slice_.exchange(false); }
bool TakeWeakTables() { return weak_tables_slice_.exchange(false); }
bool TakeIdRing() { return id_ring_slice_.exchange(false); }
bool TakeRoots() { return roots_slice_.exchange(false); }
bool TakeResetProgressBars() {
return reset_progress_bars_slice_.exchange(false);
@@ -634,18 +633,6 @@ class EpilogueTask : public SafepointTask {
TIMELINE_FUNCTION_GC_DURATION(thread, "WeakTables");
isolate_group_->heap()->ForwardWeakTables(&visitor);
}
#ifndef PRODUCT
if (state_->TakeIdRing()) {
TIMELINE_FUNCTION_GC_DURATION(thread, "IdRing");
isolate_group_->ForEachIsolate(
[&](Isolate* isolate) {
for (intptr_t i = 0; i < isolate->NumServiceIdZones(); ++i) {
isolate->GetServiceIdZone(i)->VisitPointers(visitor);
}
},
/*at_safepoint=*/true);
}
#endif // !PRODUCT
barrier_->Sync();
runtime/vm/heap/marker.cc
+2 -8
View File
@@ -751,8 +751,7 @@ void GCMarker::Epilogue() {}
enum RootSlices {
kIsolate = 0,
kObjectIdRing = 1,
kNumFixedRootSlices = 2,
kNumFixedRootSlices = 1,
};
void GCMarker::ResetSlices() {
@@ -774,18 +773,13 @@ void GCMarker::IterateRoots(ObjectPointerVisitor* visitor) {
switch (slice) {
case kIsolate: {
// TODO(gc): Split this by isolate?
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(),
"ProcessIsolateGroupRoots");
isolate_group_->VisitObjectPointers(
visitor, ValidationPolicy::kDontValidateFrames);
break;
}
case kObjectIdRing: {
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(),
"ProcessObjectIdTable");
isolate_group_->VisitPointersInAllServiceIdZones(*visitor);
break;
}
}
MonitorLocker ml(&root_slices_monitor_);
runtime/vm/heap/scavenger.cc
+3 -14
View File
@@ -1192,33 +1192,22 @@ void Scavenger::IterateRememberedCards(ScavengerVisitor* visitor) {
heap_->old_space()->VisitRememberedCards(visitor);
}
void Scavenger::IterateObjectIdTable(ObjectPointerVisitor* visitor) {
#ifndef PRODUCT
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(), "IterateObjectIdTable");
heap_->isolate_group()->VisitPointersInAllServiceIdZones(*visitor);
#endif // !PRODUCT
}
enum RootSlices {
kIsolate = 0,
kObjectIdRing,
kNumRootSlices,
kNumFixedRootSlices = 1,
};
void Scavenger::IterateRoots(ScavengerVisitor* visitor) {
for (;;) {
intptr_t slice = root_slices_started_.fetch_add(1);
if (slice >= kNumRootSlices) {
if (slice >= kNumFixedRootSlices) {
break; // No more slices.
}
switch (slice) {
case kIsolate:
// TODO(gc): Split this by isolate?
IterateIsolateRoots(visitor);
break;
case kObjectIdRing:
IterateObjectIdTable(visitor);
break;
default:
UNREACHABLE();
}
runtime/vm/heap/scavenger.h
-1
View File
@@ -281,7 +281,6 @@ class Scavenger {
void IterateIsolateRoots(ObjectPointerVisitor* visitor);
void IterateStoreBuffers(ScavengerVisitor* visitor);
void IterateRememberedCards(ScavengerVisitor* visitor);
void IterateObjectIdTable(ObjectPointerVisitor* visitor);
void IterateRoots(ScavengerVisitor* visitor);
void IterateWeak();
void MournWeakHandles();
runtime/vm/isolate.cc
+83 -52
View File
@@ -2935,53 +2935,95 @@ void IsolateGroup::VisitObjectPointers(ObjectPointerVisitor* visitor,
VisitStackPointers(visitor, validate_frames);
}
void IsolateGroup::VisitSharedPointers(ObjectPointerVisitor* visitor) {
// Visit objects in the class table.
class_table()->VisitObjectPointers(visitor);
if (heap_walk_class_table() != class_table()) {
heap_walk_class_table()->VisitObjectPointers(visitor);
}
api_state()->VisitObjectPointersUnlocked(visitor);
// Visit objects in the object store.
if (object_store() != nullptr) {
object_store()->VisitObjectPointers(visitor);
}
visitor->VisitPointer(reinterpret_cast<ObjectPtr*>(&saved_unlinked_calls_));
initial_field_table()->VisitObjectPointers(visitor);
sentinel_field_table()->VisitObjectPointers(visitor);
shared_initial_field_table()->VisitObjectPointers(visitor);
shared_field_table()->VisitObjectPointers(visitor);
// Visit the boxed_field_list_.
// 'boxed_field_list_' access via mutator and background compilation threads
// is guarded with a monitor. This means that we can visit it only
// when at safepoint or the field_list_mutex_ lock has been taken.
visitor->VisitPointer(reinterpret_cast<ObjectPtr*>(&boxed_field_list_));
NOT_IN_PRECOMPILED(background_compiler()->VisitPointers(visitor));
void IsolateGroup::VisitSharedPointers(ObjectPointerVisitor* visitor,
intptr_t slice) {
switch (slice) {
case kClassTable:
class_table()->VisitObjectPointers(visitor);
if (heap_walk_class_table() != class_table()) {
heap_walk_class_table()->VisitObjectPointers(visitor);
}
break;
case kApiState:
api_state()->VisitObjectPointersUnlocked(visitor);
break;
case kObjectStore:
if (object_store() != nullptr) {
object_store()->VisitObjectPointers(visitor);
}
break;
case kSavedUnlinkedCalls:
visitor->VisitPointer(
reinterpret_cast<ObjectPtr*>(&saved_unlinked_calls_));
break;
case kInitialFieldTable:
initial_field_table()->VisitObjectPointers(visitor);
break;
case kSentinelFieldTable:
sentinel_field_table()->VisitObjectPointers(visitor);
break;
case kSharedInitialFieldTable:
shared_initial_field_table()->VisitObjectPointers(visitor);
break;
case kSharedFieldTable:
shared_field_table()->VisitObjectPointers(visitor);
break;
case kBoxedFieldList:
// Visit the boxed_field_list_.
// 'boxed_field_list_' access via mutator and background compilation
// threads is guarded with a monitor. This means that we can visit it only
// when at safepoint or the field_list_mutex_ lock has been taken.
visitor->VisitPointer(reinterpret_cast<ObjectPtr*>(&boxed_field_list_));
break;
case kBackgroundCompiler:
NOT_IN_PRECOMPILED(background_compiler()->VisitPointers(visitor));
break;
case kDebugger:
#if !defined(PRODUCT)
if (debugger() != nullptr) {
debugger()->VisitObjectPointers(visitor);
}
if (debugger() != nullptr) {
debugger()->VisitObjectPointers(visitor);
}
#endif
break;
case kReloadContext:
#if !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
// Visit objects that are being used for isolate reload.
if (program_reload_context() != nullptr) {
program_reload_context()->VisitObjectPointers(visitor);
program_reload_context()->group_reload_context()->VisitObjectPointers(
visitor);
}
if (program_reload_context() != nullptr) {
program_reload_context()->VisitObjectPointers(visitor);
program_reload_context()->group_reload_context()->VisitObjectPointers(
visitor);
}
#endif // !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
if (source()->loaded_blobs_ != nullptr) {
visitor->VisitPointer(
reinterpret_cast<ObjectPtr*>(&(source()->loaded_blobs_)));
break;
case kLoadedBlobs:
if (source()->loaded_blobs_ != nullptr) {
visitor->VisitPointer(
reinterpret_cast<ObjectPtr*>(&(source()->loaded_blobs_)));
}
break;
case kBecome:
if (become() != nullptr) {
become()->VisitObjectPointers(visitor);
}
break;
case kObjectIdZones:
#if !defined(PRODUCT)
if (visitor->trace_object_id_rings()) {
for (Isolate* isolate : isolates_) {
for (intptr_t i = 0; i < isolate->NumServiceIdZones(); ++i) {
isolate->GetServiceIdZone(i)->VisitPointers(visitor);
}
}
}
#endif // !defined(PRODUCT)
break;
default:
UNREACHABLE();
}
}
if (become() != nullptr) {
become()->VisitObjectPointers(visitor);
void IsolateGroup::VisitSharedPointers(ObjectPointerVisitor* visitor) {
for (intptr_t i = 0; i < kNumRootSlices; i++) {
VisitSharedPointers(visitor, static_cast<RootSlice>(i));
}
}
@@ -3002,17 +3044,6 @@ void IsolateGroup::VisitStackPointers(ObjectPointerVisitor* visitor,
visitor->clear_gc_root_type();
}
void IsolateGroup::VisitPointersInAllServiceIdZones(
ObjectPointerVisitor& visitor) {
#if !defined(PRODUCT)
for (Isolate* isolate : isolates_) {
for (intptr_t i = 0; i < isolate->NumServiceIdZones(); ++i) {
isolate->GetServiceIdZone(i)->VisitPointers(visitor);
}
}
#endif // !defined(PRODUCT)
}
void IsolateGroup::VisitWeakPersistentHandles(HandleVisitor* visitor) {
api_state()->VisitWeakHandlesUnlocked(visitor);
}
runtime/vm/isolate.h
+58 -1
View File
@@ -262,6 +262,63 @@ class MutatorThreadPool : public ThreadPool {
IsolateGroup* isolate_group_ = nullptr;
};
enum RootSlice : intptr_t {
kClassTable,
kApiState,
kObjectStore,
kSavedUnlinkedCalls,
kInitialFieldTable,
kSentinelFieldTable,
kSharedInitialFieldTable,
kSharedFieldTable,
kBoxedFieldList,
kBackgroundCompiler,
kDebugger,
kReloadContext,
kLoadedBlobs,
kBecome,
kObjectIdZones,
kNumRootSlices,
};
inline const char* RootSliceToCString(intptr_t slice) {
switch (slice) {
case kClassTable:
return "class table";
case kApiState:
return "api state";
case kObjectStore:
return "group object store";
case kSavedUnlinkedCalls:
return "saved unlinked calls";
case kInitialFieldTable:
return "initial field table";
case kSentinelFieldTable:
return "sentinel field table";
case kSharedInitialFieldTable:
return "shared initial field table";
case kSharedFieldTable:
return "shared field table";
case kBoxedFieldList:
return "boxed field list";
case kBackgroundCompiler:
return "background compiler";
case kDebugger:
return "debugger";
case kReloadContext:
return "reload context";
case kLoadedBlobs:
return "loaded blobs";
case kBecome:
return "become";
case kObjectIdZones:
return "object id zones";
default:
return "?";
}
}
// Represents an isolate group and is shared among all isolates within a group.
class IsolateGroup : public IntrusiveDListEntry<IsolateGroup> {
public:
@@ -692,9 +749,9 @@ class IsolateGroup : public IntrusiveDListEntry<IsolateGroup> {
void VisitObjectPointers(ObjectPointerVisitor* visitor,
ValidationPolicy validate_frames);
void VisitSharedPointers(ObjectPointerVisitor* visitor);
void VisitSharedPointers(ObjectPointerVisitor* visitor, intptr_t slice);
void VisitStackPointers(ObjectPointerVisitor* visitor,
ValidationPolicy validate_frames);
void VisitPointersInAllServiceIdZones(ObjectPointerVisitor& visitor);
void VisitWeakPersistentHandles(HandleVisitor* visitor);
// In precompilation we finalize all regular classes before compiling.
runtime/vm/object_graph.cc
+39 -13
View File
@@ -184,6 +184,7 @@ class ObjectGraph::Stack : public ObjectPointerVisitor {
}
bool trace_values_through_fields() const override { return true; }
bool trace_object_id_rings() const override { return false; }
// Marks and pushes. Used to initialize this stack with roots.
// We can use ObjectIdTable normally used by serializers because it
@@ -660,6 +661,7 @@ class InboundReferencesVisitor : public ObjectVisitor,
}
bool trace_values_through_fields() const override { return true; }
bool trace_object_id_rings() const override { return false; }
intptr_t length() const { return length_; }
@@ -1106,9 +1108,10 @@ static constexpr intptr_t kMaxStringElements = 128;
enum ExtraCids {
kRootExtraCid = 1, // 1-origin
kImagePageExtraCid = 2,
kIsolateExtraCid = 3,
kRootSliceExtraCid = 3,
kIsolateExtraCid = 4,
kNumExtraCids = 3,
kNumExtraCids = 4,
};
class Pass2Visitor : public ObjectVisitor,
@@ -1552,7 +1555,16 @@ void HeapSnapshotWriter::Write() {
WriteUnsigned(0); // Field count
}
{
ASSERT(kIsolateExtraCid == 3);
ASSERT(kRootSliceExtraCid == 3);
WriteUnsigned(0); // Flags
WriteUtf8("Root slice"); // Name
WriteUtf8(""); // Library name
WriteUtf8(""); // Library uri
WriteUtf8(""); // Reserved
WriteUnsigned(0); // Field count
}
{
ASSERT(kIsolateExtraCid == 4);
WriteUnsigned(0); // Flags
WriteUtf8("Isolate"); // Name
WriteUtf8(""); // Library name
@@ -1570,7 +1582,6 @@ void HeapSnapshotWriter::Write() {
}
}
ASSERT(kNumExtraCids == 3);
for (intptr_t cid = 1; cid <= class_count_; cid++) {
if (!class_table->HasValidClassAt(cid)) {
WriteUnsigned(0); // Flags
@@ -1626,7 +1637,6 @@ void HeapSnapshotWriter::Write() {
// Root "objects".
{
++object_count_;
isolate_group()->VisitSharedPointers(&visitor);
}
{
++object_count_;
@@ -1635,6 +1645,10 @@ void HeapSnapshotWriter::Write() {
num_image_objects = visitor.count();
CountReferences(num_image_objects);
}
for (intptr_t i = 0; i < kNumRootSlices; i++) {
++object_count_;
isolate_group()->VisitSharedPointers(&visitor, static_cast<RootSlice>(i));
}
{
isolate_group()->ForEachIsolate(
[&](Isolate* isolate) {
@@ -1647,8 +1661,9 @@ void HeapSnapshotWriter::Write() {
},
/*at_safepoint=*/true);
}
CountReferences(1); // Root -> Image Pages
CountReferences(num_isolates); // Root -> Isolate
CountReferences(1); // Root -> Image Pages
CountReferences(kNumRootSlices); // Root -> Root slices
CountReferences(num_isolates); // Root -> Isolate
// Heap objects.
iteration.IterateVMIsolateObjects(&visitor);
@@ -1675,14 +1690,12 @@ void HeapSnapshotWriter::Write() {
WriteUnsigned(0); // shallowSize
WriteUnsigned(kNoData);
visitor.DoCount();
isolate_group()->VisitSharedPointers(&visitor);
visitor.CountExtraRefs(num_isolates + 1);
visitor.CountExtraRefs(1 + kNumRootSlices + num_isolates);
visitor.DoWrite();
isolate_group()->VisitSharedPointers(&visitor);
visitor.WriteExtraRef(2); // Root -> Image Pages
for (intptr_t i = 0; i < num_isolates; i++) {
// 0 = sentinel, 1 = root, 2 = image pages, 2+ = isolates
visitor.WriteExtraRef(i + 3);
for (intptr_t i = 0; i < num_isolates + kNumRootSlices; i++) {
// 0 = sentinel, 1 = root, 2 = image pages, 3+ = slices/isolates
visitor.WriteExtraRef(3 + i);
}
}
{
@@ -1694,6 +1707,16 @@ void HeapSnapshotWriter::Write() {
H->old_space()->VisitObjectsImagePages(&visitor);
DEBUG_ASSERT(visitor.count() == num_image_objects);
}
for (intptr_t i = 0; i < kNumRootSlices; i++) {
WriteUnsigned(kRootSliceExtraCid);
WriteUnsigned(0); // shallowSize
WriteUnsigned(kNameData);
WriteUtf8(RootSliceToCString(i));
visitor.DoCount();
isolate_group()->VisitSharedPointers(&visitor, i);
visitor.DoWrite();
isolate_group()->VisitSharedPointers(&visitor, i);
}
isolate_group()->ForEachIsolate(
[&](Isolate* isolate) {
WriteUnsigned(kIsolateExtraCid);
@@ -1741,6 +1764,9 @@ void HeapSnapshotWriter::Write() {
WriteUnsigned(0); // Root fake object.
WriteUnsigned(0); // Image pages fake object.
for (intptr_t i = 0; i < kNumRootSlices; i++) {
WriteUnsigned(0); // Root slice fake object.
}
isolate_group()->ForEachIsolate(
[&](Isolate* isolate) {
WriteUnsigned(0); // Isolate fake object.
runtime/vm/object_id_ring.cc
+3 -2
View File
@@ -68,8 +68,9 @@ ObjectPtr ObjectIdRing::GetObjectForId(int32_t id, LookupResult* kind) {
}
void ObjectIdRing::VisitPointers(ObjectPointerVisitor* visitor) const {
ASSERT(table_ != nullptr);
visitor->VisitPointers(table_, capacity_);
if (table_ != nullptr) {
visitor->VisitPointers(table_, capacity_);
}
}
void ObjectIdRing::PrintJSON(JSONStream* js) {
runtime/vm/service.cc
+2 -2
View File
@@ -446,8 +446,8 @@ void RingServiceIdZone::Invalidate() {
ring_.Invalidate();
}
void RingServiceIdZone::VisitPointers(ObjectPointerVisitor& visitor) const {
ring_.VisitPointers(&visitor);
void RingServiceIdZone::VisitPointers(ObjectPointerVisitor* visitor) const {
ring_.VisitPointers(visitor);
}
void RingServiceIdZone::PrintJSON(JSONStream& js) const {
runtime/vm/service.h
+2 -2
View File
@@ -57,7 +57,7 @@ class ServiceIdZone {
virtual char* GetServiceId(const Object& obj) = 0;
// Invalidate all the Service IDs currently living in this zone.
virtual void Invalidate() = 0;
virtual void VisitPointers(ObjectPointerVisitor& visitor) const = 0;
virtual void VisitPointers(ObjectPointerVisitor* visitor) const = 0;
virtual void PrintJSON(JSONStream& js) const = 0;
@@ -91,7 +91,7 @@ class RingServiceIdZone final : public ServiceIdZone {
// Returned string will be zone allocated.
char* GetServiceId(const Object& obj) final;
void Invalidate() final;
void VisitPointers(ObjectPointerVisitor& visitor) const final;
void VisitPointers(ObjectPointerVisitor* visitor) const final;
void PrintJSON(JSONStream& js) const final;
runtime/vm/visitor.h
+1
View File
@@ -67,6 +67,7 @@ class ObjectPointerVisitor {
// through fields.
// Otherwise trace field values through isolate's field_table.
virtual bool trace_values_through_fields() const { return false; }
virtual bool trace_object_id_rings() const { return true; }
const ClassTable* class_table() const { return class_table_; }