AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Don't record slots of objects that may contain raw values.

Browse Source 
BUG=
R=mstarzinger@chromium.org, yangguo@chromium.org

Review URL: https://codereview.chromium.org/555783002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23791 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
hpayer@chromium.org 2014-09-09 10:07:29 +00:00
parent 72e27a3d6b
commit d12834206d
4 changed files with 16 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/heap/mark-compact.cc
View File

@ -2898,10 +2898,7 @@ void MarkCompactCollector::MigrateObject(HeapObject* dst, HeapObject* src,
Memory::Object_at(dst_slot) = value;
// We special case ConstantPoolArrays below since they could contain
// integers value entries which look like tagged pointers.
// TODO(mstarzinger): restructure this code to avoid this special-casing.
if (!src->IsConstantPoolArray()) {
if (!src->MayContainRawValues()) {
RecordMigratedSlot(value, dst_slot);
}
@ -2919,6 +2916,9 @@ void MarkCompactCollector::MigrateObject(HeapObject* dst, HeapObject* src,
SlotsBuffer::IGNORE_OVERFLOW);
}
} else if (dst->IsConstantPoolArray()) {
// We special case ConstantPoolArrays since they could contain integers
// value entries which look like tagged pointers.
// TODO(mstarzinger): restructure this code to avoid this special-casing.
ConstantPoolArray* array = ConstantPoolArray::cast(dst);
ConstantPoolArray::Iterator code_iter(array, ConstantPoolArray::CODE_PTR);
while (!code_iter.is_finished()) {

2
src/heap/store-buffer.cc
View File

@ -507,7 +507,7 @@ void StoreBuffer::IteratePointersToNewSpace(ObjectSlotCallback slot_callback,
for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
heap_object = iterator.Next()) {
// We iterate over objects that contain new space pointers only.
if (heap_object->MayContainNewSpacePointers()) {
if (!heap_object->MayContainRawValues()) {
FindPointersToNewSpaceInRegion(
heap_object->address() + HeapObject::kHeaderSize,
heap_object->address() + heap_object->Size(), slot_callback,

15
src/objects-inl.h
View File

@ -1473,21 +1473,22 @@ int HeapObject::Size() {
}
bool HeapObject::MayContainNewSpacePointers() {
bool HeapObject::MayContainRawValues() {
InstanceType type = map()->instance_type();
if (type <= LAST_NAME_TYPE) {
if (type == SYMBOL_TYPE) {
return true;
return false;
}
DCHECK(type < FIRST_NONSTRING_TYPE);
// There are four string representations: sequential strings, external
// strings, cons strings, and sliced strings.
// Only the latter two contain non-map-word pointers to heap objects.
return ((type & kIsIndirectStringMask) == kIsIndirectStringTag);
// Only the former two contain raw values and no heap pointers (besides the
// map-word).
return ((type & kIsIndirectStringMask) != kIsIndirectStringTag);
}
// The ConstantPoolArray contains heap pointers, but not new space pointers.
if (type == CONSTANT_POOL_ARRAY_TYPE) return false;
return (type > LAST_DATA_TYPE);
// The ConstantPoolArray contains heap pointers, but also raw values.
if (type == CONSTANT_POOL_ARRAY_TYPE) return true;
return (type <= LAST_DATA_TYPE);
}

6
src/objects.h
View File

@ -1740,9 +1740,9 @@ class HeapObject: public Object {
// Returns the heap object's size in bytes
inline int Size();
// Returns true if this heap object may contain pointers to objects in new
// space.
inline bool MayContainNewSpacePointers();
// Returns true if this heap object may contain raw values, i.e., values that
// look like pointers to heap objects.
inline bool MayContainRawValues();
// Given a heap object's map pointer, returns the heap size in bytes
// Useful when the map pointer field is used for other purposes.