Fix two read barrier bugs introduced in CL 97882.
Bug: 12687968
Change-Id: Ib28da4c33977cc58b09913ef5b738dec75365714
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 1436810..ea02ab1 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -2563,8 +2563,9 @@
for (auto it = class_table_.lower_bound(hash), end = class_table_.end(); it != end && it->first == hash;
++it) {
- mirror::Class* entry = it->second;
- if (entry == existing) {
+ mirror::Class** root = &it->second;
+ mirror::Class* klass = ReadBarrier::BarrierForRoot<mirror::Class, kWithReadBarrier>(root);
+ if (klass == existing) {
class_table_.erase(it);
break;
}
diff --git a/runtime/mirror/class.cc b/runtime/mirror/class.cc
index be05fb8..b499a5d 100644
--- a/runtime/mirror/class.cc
+++ b/runtime/mirror/class.cc
@@ -834,13 +834,42 @@
}
}
+// The pre-fence visitor for Class::CopyOf().
+class CopyClassVisitor {
+ public:
+ explicit CopyClassVisitor(Thread* self, Handle<mirror::Class>* orig,
+ size_t new_length, size_t copy_bytes)
+ : self_(self), orig_(orig), new_length_(new_length),
+ copy_bytes_(copy_bytes) {
+ }
+
+ void operator()(Object* obj, size_t usable_size) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ UNUSED(usable_size);
+ mirror::Class* new_class_obj = obj->AsClass();
+ mirror::Object::CopyObject(self_, new_class_obj, orig_->Get(), copy_bytes_);
+ new_class_obj->SetStatus(Class::kStatusResolving, self_);
+ new_class_obj->PopulateEmbeddedImtAndVTable();
+ new_class_obj->SetClassSize(new_length_);
+ }
+
+ private:
+ Thread* const self_;
+ Handle<mirror::Class>* const orig_;
+ const size_t new_length_;
+ const size_t copy_bytes_;
+ DISALLOW_COPY_AND_ASSIGN(CopyClassVisitor);
+};
+
Class* Class::CopyOf(Thread* self, int32_t new_length) {
DCHECK_GE(new_length, static_cast<int32_t>(sizeof(Class)));
// We may get copied by a compacting GC.
StackHandleScope<1> hs(self);
Handle<mirror::Class> h_this(hs.NewHandle(this));
gc::Heap* heap = Runtime::Current()->GetHeap();
- InitializeClassVisitor visitor(new_length);
+ // The num_bytes (3rd param) is sizeof(Class) as opposed to SizeOf()
+ // to skip copying the tail part that we will overwrite here.
+ CopyClassVisitor visitor(self, &h_this, new_length, sizeof(Class));
mirror::Object* new_class =
kMovingClasses ? heap->AllocObject<true>(self, java_lang_Class_, new_length, visitor)
@@ -850,17 +879,7 @@
return NULL;
}
- mirror::Class* new_class_obj = new_class->AsClass();
- memcpy(new_class_obj, h_this.Get(), sizeof(Class));
-
- new_class_obj->SetStatus(kStatusResolving, self);
- new_class_obj->PopulateEmbeddedImtAndVTable();
- // Correct some fields.
- new_class_obj->SetLockWord(LockWord(), false);
- new_class_obj->SetClassSize(new_length);
-
- Runtime::Current()->GetHeap()->WriteBarrierEveryFieldOf(new_class_obj);
- return new_class_obj;
+ return new_class->AsClass();
}
} // namespace mirror
diff --git a/runtime/mirror/object.cc b/runtime/mirror/object.cc
index 5f88d54..97d88cf 100644
--- a/runtime/mirror/object.cc
+++ b/runtime/mirror/object.cc
@@ -65,8 +65,8 @@
Object* const dest_obj_;
};
-static Object* CopyObject(Thread* self, mirror::Object* dest, mirror::Object* src, size_t num_bytes)
- SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+Object* Object::CopyObject(Thread* self, mirror::Object* dest, mirror::Object* src,
+ size_t num_bytes) {
// Copy instance data. We assume memcpy copies by words.
// TODO: expose and use move32.
byte* src_bytes = reinterpret_cast<byte*>(src);
@@ -107,7 +107,7 @@
void operator()(Object* obj, size_t usable_size) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
UNUSED(usable_size);
- CopyObject(self_, obj, orig_->Get(), num_bytes_);
+ Object::CopyObject(self_, obj, orig_->Get(), num_bytes_);
}
private:
diff --git a/runtime/mirror/object.h b/runtime/mirror/object.h
index 4fae470..a6b6227 100644
--- a/runtime/mirror/object.h
+++ b/runtime/mirror/object.h
@@ -370,6 +370,13 @@
// Generate an identity hash code.
static int32_t GenerateIdentityHashCode();
+ // A utility function that copies an object in a read barrier and
+ // write barrier-aware way. This is internally used by Clone() and
+ // Class::CopyOf().
+ static Object* CopyObject(Thread* self, mirror::Object* dest, mirror::Object* src,
+ size_t num_bytes)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
// The Class representing the type of the object.
HeapReference<Class> klass_;
// Monitor and hash code information.
@@ -386,6 +393,8 @@
friend class art::ImageWriter;
friend class art::Monitor;
friend struct art::ObjectOffsets; // for verifying offset information
+ friend class CopyObjectVisitor; // for CopyObject().
+ friend class CopyClassVisitor; // for CopyObject().
DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
};