Move mirror::Class to use ObjPtr

Leave the return types as non ObjPtr for now. Fixed moving GC bugs
in tests.

Test: test-art-host

Bug: 31113334

Change-Id: I5da1b5ac55dfbc5cc97a64be2c870ba9f512d9b0
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index 98d383d..02c987c 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -306,14 +306,14 @@
   SetEmbeddedVTableEntryUnchecked(i, method, pointer_size);
 }
 
-inline bool Class::Implements(Class* klass) {
+inline bool Class::Implements(ObjPtr<Class> klass) {
   DCHECK(klass != nullptr);
   DCHECK(klass->IsInterface()) << PrettyClass(this);
   // All interfaces implemented directly and by our superclass, and
   // recursively all super-interfaces of those interfaces, are listed
   // in iftable_, so we can just do a linear scan through that.
   int32_t iftable_count = GetIfTableCount();
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   for (int32_t i = 0; i < iftable_count; i++) {
     if (iftable->GetInterface(i) == klass) {
       return true;
@@ -353,7 +353,7 @@
   if (!IsArrayClass()) {
     // If "this" is not also an array, it must be Object.
     // src's super should be java_lang_Object, since it is an array.
-    Class* java_lang_Object = src->GetSuperClass();
+    ObjPtr<Class> java_lang_Object = src->GetSuperClass();
     DCHECK(java_lang_Object != nullptr) << PrettyClass(src);
     DCHECK(java_lang_Object->GetSuperClass() == nullptr) << PrettyClass(src);
     return this == java_lang_Object;
@@ -451,15 +451,20 @@
   return ResolvedFieldAccessTest<true, true>(access_to, field, field_idx, nullptr);
 }
 
-inline bool Class::CanAccessResolvedMethod(Class* access_to, ArtMethod* method,
-                                           DexCache* dex_cache, uint32_t method_idx) {
+inline bool Class::CanAccessResolvedMethod(ObjPtr<Class> access_to,
+                                           ArtMethod* method,
+                                           ObjPtr<DexCache> dex_cache,
+                                           uint32_t method_idx) {
   return ResolvedMethodAccessTest<false, false, kStatic>(access_to, method, method_idx, dex_cache);
 }
 
 template <InvokeType throw_invoke_type>
-inline bool Class::CheckResolvedMethodAccess(Class* access_to, ArtMethod* method,
+inline bool Class::CheckResolvedMethodAccess(ObjPtr<Class> access_to,
+                                             ArtMethod* method,
                                              uint32_t method_idx) {
-  return ResolvedMethodAccessTest<true, true, throw_invoke_type>(access_to, method, method_idx,
+  return ResolvedMethodAccessTest<true, true, throw_invoke_type>(access_to,
+                                                                 method,
+                                                                 method_idx,
                                                                  nullptr);
 }
 
@@ -478,13 +483,13 @@
 
 inline ArtMethod* Class::FindVirtualMethodForInterface(ArtMethod* method,
                                                        PointerSize pointer_size) {
-  Class* declaring_class = method->GetDeclaringClass();
+  ObjPtr<Class> declaring_class = method->GetDeclaringClass();
   DCHECK(declaring_class != nullptr) << PrettyClass(this);
   DCHECK(declaring_class->IsInterface()) << PrettyMethod(method);
   DCHECK(!method->IsCopied());
   // TODO cache to improve lookup speed
   const int32_t iftable_count = GetIfTableCount();
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   for (int32_t i = 0; i < iftable_count; i++) {
     if (iftable->GetInterface(i) == declaring_class) {
       return iftable->GetMethodArray(i)->GetElementPtrSize<ArtMethod*>(
@@ -526,14 +531,14 @@
 }
 
 inline int32_t Class::GetIfTableCount() {
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   if (iftable == nullptr) {
     return 0;
   }
   return iftable->Count();
 }
 
-inline void Class::SetIfTable(IfTable* new_iftable) {
+inline void Class::SetIfTable(ObjPtr<IfTable> new_iftable) {
   SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, iftable_), new_iftable);
 }
 
@@ -544,20 +549,20 @@
 
 template<VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
 inline MemberOffset Class::GetFirstReferenceInstanceFieldOffset() {
-  Class* super_class = GetSuperClass<kVerifyFlags, kReadBarrierOption>();
+  ObjPtr<Class> super_class = GetSuperClass<kVerifyFlags, kReadBarrierOption>();
   return (super_class != nullptr)
       ? MemberOffset(RoundUp(super_class->GetObjectSize<kVerifyFlags, kReadBarrierOption>(),
-                             sizeof(mirror::HeapReference<mirror::Object>)))
+                             kHeapReferenceSize))
       : ClassOffset();
 }
 
 template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
 inline MemberOffset Class::GetFirstReferenceStaticFieldOffset(PointerSize pointer_size) {
   DCHECK(IsResolved());
-  uint32_t base = sizeof(mirror::Class);  // Static fields come after the class.
+  uint32_t base = sizeof(Class);  // Static fields come after the class.
   if (ShouldHaveEmbeddedVTable<kVerifyFlags, kReadBarrierOption>()) {
     // Static fields come after the embedded tables.
-    base = mirror::Class::ComputeClassSize(
+    base = Class::ComputeClassSize(
         true, GetEmbeddedVTableLength(), 0, 0, 0, 0, 0, pointer_size);
   }
   return MemberOffset(base);
@@ -566,10 +571,10 @@
 inline MemberOffset Class::GetFirstReferenceStaticFieldOffsetDuringLinking(
     PointerSize pointer_size) {
   DCHECK(IsLoaded());
-  uint32_t base = sizeof(mirror::Class);  // Static fields come after the class.
+  uint32_t base = sizeof(Class);  // Static fields come after the class.
   if (ShouldHaveEmbeddedVTable()) {
     // Static fields come after the embedded tables.
-    base = mirror::Class::ComputeClassSize(true, GetVTableDuringLinking()->GetLength(),
+    base = Class::ComputeClassSize(true, GetVTableDuringLinking()->GetLength(),
                                            0, 0, 0, 0, 0, pointer_size);
   }
   return MemberOffset(base);
@@ -700,7 +705,7 @@
 }
 
 template<bool kIsInstrumented, bool kCheckAddFinalizer>
-inline Object* Class::Alloc(Thread* self, gc::AllocatorType allocator_type) {
+inline ObjPtr<Object> Class::Alloc(Thread* self, gc::AllocatorType allocator_type) {
   CheckObjectAlloc();
   gc::Heap* heap = Runtime::Current()->GetHeap();
   const bool add_finalizer = kCheckAddFinalizer && IsFinalizable();
@@ -708,7 +713,7 @@
     DCHECK(!IsFinalizable());
   }
   // Note that the this pointer may be invalidated after the allocation.
-  ObjPtr<mirror::Object> obj =
+  ObjPtr<Object> obj =
       heap->AllocObjectWithAllocator<kIsInstrumented, false>(self,
                                                              this,
                                                              this->object_size_,
@@ -724,11 +729,11 @@
   return obj.Ptr();
 }
 
-inline Object* Class::AllocObject(Thread* self) {
+inline ObjPtr<Object> Class::AllocObject(Thread* self) {
   return Alloc<true>(self, Runtime::Current()->GetHeap()->GetCurrentAllocator());
 }
 
-inline Object* Class::AllocNonMovableObject(Thread* self) {
+inline ObjPtr<Object> Class::AllocNonMovableObject(Thread* self) {
   return Alloc<true>(self, Runtime::Current()->GetHeap()->GetCurrentNonMovingAllocator());
 }
 
@@ -750,7 +755,7 @@
   }
 
   // Space used by reference statics.
-  size += num_ref_static_fields * sizeof(HeapReference<Object>);
+  size += num_ref_static_fields * kHeapReferenceSize;
   if (!IsAligned<8>(size) && num_64bit_static_fields > 0) {
     uint32_t gap = 8 - (size & 0x7);
     size += gap;  // will be padded
@@ -781,8 +786,8 @@
           VerifyObjectFlags kVerifyFlags,
           ReadBarrierOption kReadBarrierOption,
           typename Visitor>
-inline void Class::VisitReferences(mirror::Class* klass, const Visitor& visitor) {
-  VisitInstanceFieldsReferences<kVerifyFlags, kReadBarrierOption>(klass, visitor);
+inline void Class::VisitReferences(ObjPtr<Class> klass, const Visitor& visitor) {
+  VisitInstanceFieldsReferences<kVerifyFlags, kReadBarrierOption>(klass.Ptr(), visitor);
   // Right after a class is allocated, but not yet loaded
   // (kStatusNotReady, see ClassLinker::LoadClass()), GC may find it
   // and scan it. IsTemp() may call Class::GetAccessFlags() but may
@@ -810,7 +815,7 @@
 
 template<VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
 inline bool Class::IsClassClass() {
-  Class* java_lang_Class = GetClass<kVerifyFlags, kReadBarrierOption>()->
+  ObjPtr<Class> java_lang_Class = GetClass<kVerifyFlags, kReadBarrierOption>()->
       template GetClass<kVerifyFlags, kReadBarrierOption>();
   return this == java_lang_Class;
 }
@@ -883,12 +888,11 @@
   SetFieldBoolean<false, false>(GetSlowPathFlagOffset(), enabled);
 }
 
-inline void Class::InitializeClassVisitor::operator()(ObjPtr<mirror::Object> obj,
+inline void Class::InitializeClassVisitor::operator()(ObjPtr<Object> obj,
                                                       size_t usable_size) const {
   DCHECK_LE(class_size_, usable_size);
   // Avoid AsClass as object is not yet in live bitmap or allocation stack.
-  ObjPtr<mirror::Class> klass = ObjPtr<mirror::Class>::DownCast(obj);
-  // DCHECK(klass->IsClass());
+  ObjPtr<Class> klass = ObjPtr<Class>::DownCast(obj);
   klass->SetClassSize(class_size_);
   klass->SetPrimitiveType(Primitive::kPrimNot);  // Default to not being primitive.
   klass->SetDexClassDefIndex(DexFile::kDexNoIndex16);  // Default to no valid class def index.
@@ -920,7 +924,7 @@
   } else if (IsArrayClass()) {
     return 2;
   } else if (IsProxyClass()) {
-    mirror::ObjectArray<mirror::Class>* interfaces = GetInterfaces();
+    ObjectArray<Class>* interfaces = GetInterfaces();
     return interfaces != nullptr ? interfaces->GetLength() : 0;
   } else {
     const DexFile::TypeList* interfaces = GetInterfaceTypeList();
@@ -941,7 +945,7 @@
 }
 
 template<ReadBarrierOption kReadBarrierOption, class Visitor>
-void mirror::Class::VisitNativeRoots(Visitor& visitor, PointerSize pointer_size) {
+void Class::VisitNativeRoots(Visitor& visitor, PointerSize pointer_size) {
   for (ArtField& field : GetSFieldsUnchecked()) {
     // Visit roots first in case the declaring class gets moved.
     field.VisitRoots(visitor);
@@ -1070,7 +1074,7 @@
 }
 
 template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption, typename Visitor>
-inline void Class::FixupNativePointers(mirror::Class* dest,
+inline void Class::FixupNativePointers(Class* dest,
                                        PointerSize pointer_size,
                                        const Visitor& visitor) {
   // Update the field arrays.
@@ -1139,6 +1143,14 @@
   return this->IsInSamePackage(access_to);
 }
 
+inline bool Class::CannotBeAssignedFromOtherTypes() {
+  if (!IsArrayClass()) {
+    return IsFinal();
+  }
+  ObjPtr<Class> component = GetComponentType();
+  return component->IsPrimitive() || component->CannotBeAssignedFromOtherTypes();
+}
+
 }  // namespace mirror
 }  // namespace art
 
diff --git a/runtime/mirror/class.cc b/runtime/mirror/class.cc
index 689dd22..f93f72f 100644
--- a/runtime/mirror/class.cc
+++ b/runtime/mirror/class.cc
@@ -40,12 +40,12 @@
 
 GcRoot<Class> Class::java_lang_Class_;
 
-void Class::SetClassClass(Class* java_lang_Class) {
+void Class::SetClassClass(ObjPtr<Class> java_lang_Class) {
   CHECK(java_lang_Class_.IsNull())
       << java_lang_Class_.Read()
       << " " << java_lang_Class;
   CHECK(java_lang_Class != nullptr);
-  java_lang_Class->SetClassFlags(mirror::kClassFlagClass);
+  java_lang_Class->SetClassFlags(kClassFlagClass);
   java_lang_Class_ = GcRoot<Class>(java_lang_Class);
 }
 
@@ -58,7 +58,7 @@
   java_lang_Class_.VisitRootIfNonNull(visitor, RootInfo(kRootStickyClass));
 }
 
-inline void Class::SetVerifyError(mirror::Object* error) {
+inline void Class::SetVerifyError(ObjPtr<Object> error) {
   CHECK(error != nullptr) << PrettyClass(this);
   if (Runtime::Current()->IsActiveTransaction()) {
     SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, verify_error_), error);
@@ -140,7 +140,7 @@
   }
 }
 
-void Class::SetDexCache(DexCache* new_dex_cache) {
+void Class::SetDexCache(ObjPtr<DexCache> new_dex_cache) {
   SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_), new_dex_cache);
   SetDexCacheStrings(new_dex_cache != nullptr ? new_dex_cache->GetStrings() : nullptr);
 }
@@ -209,8 +209,8 @@
 
   Thread* const self = Thread::Current();
   StackHandleScope<2> hs(self);
-  Handle<mirror::Class> h_this(hs.NewHandle(this));
-  Handle<mirror::Class> h_super(hs.NewHandle(GetSuperClass()));
+  Handle<Class> h_this(hs.NewHandle(this));
+  Handle<Class> h_super(hs.NewHandle(GetSuperClass()));
   auto image_pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
 
   std::string temp;
@@ -231,12 +231,12 @@
   if (num_direct_interfaces > 0) {
     os << "  interfaces (" << num_direct_interfaces << "):\n";
     for (size_t i = 0; i < num_direct_interfaces; ++i) {
-      Class* interface = GetDirectInterface(self, h_this, i);
+      ObjPtr<Class> interface = GetDirectInterface(self, h_this, i);
       if (interface == nullptr) {
         os << StringPrintf("    %2zd: nullptr!\n", i);
       } else {
-        const ClassLoader* cl = interface->GetClassLoader();
-        os << StringPrintf("    %2zd: %s (cl=%p)\n", i, PrettyClass(interface).c_str(), cl);
+        ObjPtr<ClassLoader> cl = interface->GetClassLoader();
+        os << StringPrintf("    %2zd: %s (cl=%p)\n", i, PrettyClass(interface).c_str(), cl.Ptr());
       }
     }
   }
@@ -283,7 +283,7 @@
     // Sanity check that the number of bits set in the reference offset bitmap
     // agrees with the number of references
     uint32_t count = 0;
-    for (Class* c = this; c != nullptr; c = c->GetSuperClass()) {
+    for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
       count += c->NumReferenceInstanceFieldsDuringLinking();
     }
     // +1 for the Class in Object.
@@ -338,7 +338,7 @@
   return WellKnownClasses::ToClass(WellKnownClasses::java_lang_Throwable)->IsAssignableFrom(this);
 }
 
-void Class::SetClassLoader(ClassLoader* new_class_loader) {
+void Class::SetClassLoader(ObjPtr<ClassLoader> new_class_loader) {
   if (Runtime::Current()->IsActiveTransaction()) {
     SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader);
   } else {
@@ -356,7 +356,7 @@
   }
 
   int32_t iftable_count = GetIfTableCount();
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   for (int32_t i = 0; i < iftable_count; ++i) {
     method = iftable->GetInterface(i)->FindDeclaredVirtualMethod(name, signature, pointer_size);
     if (method != nullptr) {
@@ -376,7 +376,7 @@
   }
 
   int32_t iftable_count = GetIfTableCount();
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   for (int32_t i = 0; i < iftable_count; ++i) {
     method = iftable->GetInterface(i)->FindDeclaredVirtualMethod(name, signature, pointer_size);
     if (method != nullptr) {
@@ -386,7 +386,7 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindInterfaceMethod(const DexCache* dex_cache,
+ArtMethod* Class::FindInterfaceMethod(ObjPtr<DexCache> dex_cache,
                                       uint32_t dex_method_idx,
                                       PointerSize pointer_size) {
   // Check the current class before checking the interfaces.
@@ -396,7 +396,7 @@
   }
 
   int32_t iftable_count = GetIfTableCount();
-  IfTable* iftable = GetIfTable();
+  ObjPtr<IfTable> iftable = GetIfTable();
   for (int32_t i = 0; i < iftable_count; ++i) {
     method = iftable->GetInterface(i)->FindDeclaredVirtualMethod(
         dex_cache, dex_method_idx, pointer_size);
@@ -429,7 +429,7 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindDeclaredDirectMethod(const DexCache* dex_cache,
+ArtMethod* Class::FindDeclaredDirectMethod(ObjPtr<DexCache> dex_cache,
                                            uint32_t dex_method_idx,
                                            PointerSize pointer_size) {
   if (GetDexCache() == dex_cache) {
@@ -445,7 +445,7 @@
 ArtMethod* Class::FindDirectMethod(const StringPiece& name,
                                    const StringPiece& signature,
                                    PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredDirectMethod(name, signature, pointer_size);
     if (method != nullptr) {
       return method;
@@ -457,7 +457,7 @@
 ArtMethod* Class::FindDirectMethod(const StringPiece& name,
                                    const Signature& signature,
                                    PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredDirectMethod(name, signature, pointer_size);
     if (method != nullptr) {
       return method;
@@ -466,9 +466,10 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindDirectMethod(
-    const DexCache* dex_cache, uint32_t dex_method_idx, PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+ArtMethod* Class::FindDirectMethod(ObjPtr<DexCache> dex_cache,
+                                   uint32_t dex_method_idx,
+                                   PointerSize pointer_size) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredDirectMethod(dex_cache, dex_method_idx, pointer_size);
     if (method != nullptr) {
       return method;
@@ -516,7 +517,7 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindDeclaredVirtualMethod(const DexCache* dex_cache,
+ArtMethod* Class::FindDeclaredVirtualMethod(ObjPtr<DexCache> dex_cache,
                                             uint32_t dex_method_idx,
                                             PointerSize pointer_size) {
   if (GetDexCache() == dex_cache) {
@@ -540,9 +541,10 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindVirtualMethod(
-    const StringPiece& name, const StringPiece& signature, PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+ArtMethod* Class::FindVirtualMethod(const StringPiece& name,
+                                    const StringPiece& signature,
+                                    PointerSize pointer_size) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredVirtualMethod(name, signature, pointer_size);
     if (method != nullptr) {
       return method;
@@ -551,9 +553,10 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindVirtualMethod(
-    const StringPiece& name, const Signature& signature, PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+ArtMethod* Class::FindVirtualMethod(const StringPiece& name,
+                                    const Signature& signature,
+                                    PointerSize pointer_size) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredVirtualMethod(name, signature, pointer_size);
     if (method != nullptr) {
       return method;
@@ -562,9 +565,10 @@
   return nullptr;
 }
 
-ArtMethod* Class::FindVirtualMethod(
-    const DexCache* dex_cache, uint32_t dex_method_idx, PointerSize pointer_size) {
-  for (Class* klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
+ArtMethod* Class::FindVirtualMethod(ObjPtr<DexCache> dex_cache,
+                                    uint32_t dex_method_idx,
+                                    PointerSize pointer_size) {
+  for (ObjPtr<Class> klass = this; klass != nullptr; klass = klass->GetSuperClass()) {
     ArtMethod* method = klass->FindDeclaredVirtualMethod(dex_cache, dex_method_idx, pointer_size);
     if (method != nullptr) {
       return method;
@@ -591,8 +595,8 @@
 
   Thread* self = Thread::Current();
   StackHandleScope<2> hs(self);
-  MutableHandle<mirror::IfTable> iftable(hs.NewHandle(GetIfTable()));
-  MutableHandle<mirror::Class> iface(hs.NewHandle<mirror::Class>(nullptr));
+  MutableHandle<IfTable> iftable(hs.NewHandle(GetIfTable()));
+  MutableHandle<Class> iface(hs.NewHandle<Class>(nullptr));
   size_t iftable_count = GetIfTableCount();
   // Find the method. We don't need to check for conflicts because they would have been in the
   // copied virtuals of this interface.  Order matters, traverse in reverse topological order; most
@@ -696,7 +700,7 @@
   return FindFieldByNameAndType(GetIFieldsPtr(), name, type);
 }
 
-ArtField* Class::FindDeclaredInstanceField(const DexCache* dex_cache, uint32_t dex_field_idx) {
+ArtField* Class::FindDeclaredInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
   if (GetDexCache() == dex_cache) {
     for (ArtField& field : GetIFields()) {
       if (field.GetDexFieldIndex() == dex_field_idx) {
@@ -710,7 +714,7 @@
 ArtField* Class::FindInstanceField(const StringPiece& name, const StringPiece& type) {
   // Is the field in this class, or any of its superclasses?
   // Interfaces are not relevant because they can't contain instance fields.
-  for (Class* c = this; c != nullptr; c = c->GetSuperClass()) {
+  for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
     ArtField* f = c->FindDeclaredInstanceField(name, type);
     if (f != nullptr) {
       return f;
@@ -719,10 +723,10 @@
   return nullptr;
 }
 
-ArtField* Class::FindInstanceField(const DexCache* dex_cache, uint32_t dex_field_idx) {
+ArtField* Class::FindInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
   // Is the field in this class, or any of its superclasses?
   // Interfaces are not relevant because they can't contain instance fields.
-  for (Class* c = this; c != nullptr; c = c->GetSuperClass()) {
+  for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
     ArtField* f = c->FindDeclaredInstanceField(dex_cache, dex_field_idx);
     if (f != nullptr) {
       return f;
@@ -736,7 +740,7 @@
   return FindFieldByNameAndType(GetSFieldsPtr(), name, type);
 }
 
-ArtField* Class::FindDeclaredStaticField(const DexCache* dex_cache, uint32_t dex_field_idx) {
+ArtField* Class::FindDeclaredStaticField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
   if (dex_cache == GetDexCache()) {
     for (ArtField& field : GetSFields()) {
       if (field.GetDexFieldIndex() == dex_field_idx) {
@@ -747,11 +751,13 @@
   return nullptr;
 }
 
-ArtField* Class::FindStaticField(Thread* self, Handle<Class> klass, const StringPiece& name,
+ArtField* Class::FindStaticField(Thread* self,
+                                 Handle<Class> klass,
+                                 const StringPiece& name,
                                  const StringPiece& type) {
   // Is the field in this class (or its interfaces), or any of its
   // superclasses (or their interfaces)?
-  for (Class* k = klass.Get(); k != nullptr; k = k->GetSuperClass()) {
+  for (ObjPtr<Class> k = klass.Get(); k != nullptr; k = k->GetSuperClass()) {
     // Is the field in this class?
     ArtField* f = k->FindDeclaredStaticField(name, type);
     if (f != nullptr) {
@@ -759,11 +765,11 @@
     }
     // Wrap k incase it moves during GetDirectInterface.
     StackHandleScope<1> hs(self);
-    HandleWrapper<mirror::Class> h_k(hs.NewHandleWrapper(&k));
+    HandleWrapperObjPtr<Class> h_k(hs.NewHandleWrapper(&k));
     // Is this field in any of this class' interfaces?
     for (uint32_t i = 0; i < h_k->NumDirectInterfaces(); ++i) {
       StackHandleScope<1> hs2(self);
-      Handle<mirror::Class> interface(hs2.NewHandle(GetDirectInterface(self, h_k, i)));
+      Handle<Class> interface(hs2.NewHandle(GetDirectInterface(self, h_k, i)));
       f = FindStaticField(self, interface, name, type);
       if (f != nullptr) {
         return f;
@@ -774,10 +780,10 @@
 }
 
 ArtField* Class::FindStaticField(Thread* self,
-                                 Class* klass,
-                                 const DexCache* dex_cache,
+                                 ObjPtr<Class> klass,
+                                 ObjPtr<DexCache> dex_cache,
                                  uint32_t dex_field_idx) {
-  for (Class* k = klass; k != nullptr; k = k->GetSuperClass()) {
+  for (ObjPtr<Class> k = klass; k != nullptr; k = k->GetSuperClass()) {
     // Is the field in this class?
     ArtField* f = k->FindDeclaredStaticField(dex_cache, dex_field_idx);
     if (f != nullptr) {
@@ -787,10 +793,10 @@
     // from here, it takes a Handle as an argument, so we need to wrap `k`.
     ScopedAssertNoThreadSuspension ants(__FUNCTION__);
     StackHandleScope<1> hs(self);
-    Handle<mirror::Class> h_k(hs.NewHandle(k));
+    Handle<Class> h_k(hs.NewHandle(k));
     // Is this field in any of this class' interfaces?
     for (uint32_t i = 0; i < h_k->NumDirectInterfaces(); ++i) {
-      mirror::Class* interface = GetDirectInterface(self, h_k, i);
+      ObjPtr<Class> interface = GetDirectInterface(self, h_k, i);
       f = FindStaticField(self, interface, dex_cache, dex_field_idx);
       if (f != nullptr) {
         return f;
@@ -800,10 +806,12 @@
   return nullptr;
 }
 
-ArtField* Class::FindField(Thread* self, Handle<Class> klass, const StringPiece& name,
+ArtField* Class::FindField(Thread* self,
+                           Handle<Class> klass,
+                           const StringPiece& name,
                            const StringPiece& type) {
   // Find a field using the JLS field resolution order
-  for (Class* k = klass.Get(); k != nullptr; k = k->GetSuperClass()) {
+  for (ObjPtr<Class> k = klass.Get(); k != nullptr; k = k->GetSuperClass()) {
     // Is the field in this class?
     ArtField* f = k->FindDeclaredInstanceField(name, type);
     if (f != nullptr) {
@@ -815,10 +823,10 @@
     }
     // Is this field in any of this class' interfaces?
     StackHandleScope<1> hs(self);
-    HandleWrapper<mirror::Class> h_k(hs.NewHandleWrapper(&k));
+    HandleWrapperObjPtr<Class> h_k(hs.NewHandleWrapper(&k));
     for (uint32_t i = 0; i < h_k->NumDirectInterfaces(); ++i) {
       StackHandleScope<1> hs2(self);
-      Handle<mirror::Class> interface(hs2.NewHandle(GetDirectInterface(self, h_k, i)));
+      Handle<Class> interface(hs2.NewHandle(GetDirectInterface(self, h_k, i)));
       f = interface->FindStaticField(self, interface, name, type);
       if (f != nullptr) {
         return f;
@@ -874,8 +882,9 @@
   return GetInterfaceTypeList()->GetTypeItem(idx).type_idx_;
 }
 
-mirror::Class* Class::GetDirectInterface(Thread* self, Handle<mirror::Class> klass,
-                                         uint32_t idx) {
+ObjPtr<Class> Class::GetDirectInterface(Thread* self,
+                                        Handle<Class> klass,
+                                        uint32_t idx) {
   DCHECK(klass.Get() != nullptr);
   DCHECK(!klass->IsPrimitive());
   if (klass->IsArrayClass()) {
@@ -887,12 +896,12 @@
       return class_linker->FindSystemClass(self, "Ljava/io/Serializable;");
     }
   } else if (klass->IsProxyClass()) {
-    mirror::ObjectArray<mirror::Class>* interfaces = klass.Get()->GetInterfaces();
+    ObjPtr<ObjectArray<Class>> interfaces = klass.Get()->GetInterfaces();
     DCHECK(interfaces != nullptr);
     return interfaces->Get(idx);
   } else {
     uint16_t type_idx = klass->GetDirectInterfaceTypeIdx(idx);
-    mirror::Class* interface = klass->GetDexCache()->GetResolvedType(type_idx);
+    ObjPtr<Class> interface = klass->GetDexCache()->GetResolvedType(type_idx);
     if (interface == nullptr) {
       interface = Runtime::Current()->GetClassLinker()->ResolveType(klass->GetDexFile(), type_idx,
                                                                     klass.Get());
@@ -902,13 +911,13 @@
   }
 }
 
-mirror::Class* Class::GetCommonSuperClass(Handle<Class> klass) {
+ObjPtr<Class> Class::GetCommonSuperClass(Handle<Class> klass) {
   DCHECK(klass.Get() != nullptr);
   DCHECK(!klass->IsInterface());
   DCHECK(!IsInterface());
-  mirror::Class* common_super_class = this;
+  ObjPtr<Class> common_super_class = this;
   while (!common_super_class->IsAssignableFrom(klass.Get())) {
-    mirror::Class* old_common = common_super_class;
+    ObjPtr<Class> old_common = common_super_class;
     common_super_class = old_common->GetSuperClass();
     DCHECK(common_super_class != nullptr) << PrettyClass(old_common);
   }
@@ -926,7 +935,7 @@
 }
 
 std::string Class::GetLocation() {
-  mirror::DexCache* dex_cache = GetDexCache();
+  ObjPtr<DexCache> dex_cache = GetDexCache();
   if (dex_cache != nullptr && !IsProxyClass()) {
     return dex_cache->GetLocation()->ToModifiedUtf8();
   }
@@ -959,28 +968,28 @@
 
 class ReadBarrierOnNativeRootsVisitor {
  public:
-  void operator()(mirror::Object* obj ATTRIBUTE_UNUSED,
+  void operator()(ObjPtr<Object> obj ATTRIBUTE_UNUSED,
                   MemberOffset offset ATTRIBUTE_UNUSED,
                   bool is_static ATTRIBUTE_UNUSED) const {}
 
-  void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root) const
+  void VisitRootIfNonNull(CompressedReference<Object>* root) const
       REQUIRES_SHARED(Locks::mutator_lock_) {
     if (!root->IsNull()) {
       VisitRoot(root);
     }
   }
 
-  void VisitRoot(mirror::CompressedReference<mirror::Object>* root) const
+  void VisitRoot(CompressedReference<Object>* root) const
       REQUIRES_SHARED(Locks::mutator_lock_) {
-    mirror::Object* old_ref = root->AsMirrorPtr();
-    mirror::Object* new_ref = ReadBarrier::BarrierForRoot(root);
+    ObjPtr<Object> old_ref = root->AsMirrorPtr();
+    ObjPtr<Object> new_ref = ReadBarrier::BarrierForRoot(root);
     if (old_ref != new_ref) {
       // Update the field atomically. This may fail if mutator updates before us, but it's ok.
       auto* atomic_root =
-          reinterpret_cast<Atomic<mirror::CompressedReference<mirror::Object>>*>(root);
+          reinterpret_cast<Atomic<CompressedReference<Object>>*>(root);
       atomic_root->CompareExchangeStrongSequentiallyConsistent(
-          mirror::CompressedReference<mirror::Object>::FromMirrorPtr(old_ref),
-          mirror::CompressedReference<mirror::Object>::FromMirrorPtr(new_ref));
+          CompressedReference<Object>::FromMirrorPtr(old_ref.Ptr()),
+          CompressedReference<Object>::FromMirrorPtr(new_ref.Ptr()));
     }
   }
 };
@@ -989,7 +998,7 @@
 class CopyClassVisitor {
  public:
   CopyClassVisitor(Thread* self,
-                   Handle<mirror::Class>* orig,
+                   Handle<Class>* orig,
                    size_t new_length,
                    size_t copy_bytes,
                    ImTable* imt,
@@ -998,24 +1007,24 @@
         copy_bytes_(copy_bytes), imt_(imt), pointer_size_(pointer_size) {
   }
 
-  void operator()(ObjPtr<mirror::Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
+  void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
       REQUIRES_SHARED(Locks::mutator_lock_) {
     StackHandleScope<1> hs(self_);
     Handle<mirror::Class> h_new_class_obj(hs.NewHandle(obj->AsClass()));
-    mirror::Object::CopyObject(h_new_class_obj.Get(), orig_->Get(), copy_bytes_);
-    mirror::Class::SetStatus(h_new_class_obj, Class::kStatusResolving, self_);
+    Object::CopyObject(h_new_class_obj.Get(), orig_->Get(), copy_bytes_);
+    Class::SetStatus(h_new_class_obj, Class::kStatusResolving, self_);
     h_new_class_obj->PopulateEmbeddedVTable(pointer_size_);
     h_new_class_obj->SetImt(imt_, pointer_size_);
     h_new_class_obj->SetClassSize(new_length_);
     // Visit all of the references to make sure there is no from space references in the native
     // roots.
-    static_cast<mirror::Object*>(h_new_class_obj.Get())->VisitReferences(
+    ObjPtr<Object>(h_new_class_obj.Get())->VisitReferences(
         ReadBarrierOnNativeRootsVisitor(), VoidFunctor());
   }
 
  private:
   Thread* const self_;
-  Handle<mirror::Class>* const orig_;
+  Handle<Class>* const orig_;
   const size_t new_length_;
   const size_t copy_bytes_;
   ImTable* imt_;
@@ -1027,12 +1036,12 @@
   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));
+  Handle<Class> h_this(hs.NewHandle(this));
   gc::Heap* heap = Runtime::Current()->GetHeap();
   // 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), imt, pointer_size);
-  mirror::Object* new_class = kMovingClasses ?
+  ObjPtr<Object> new_class = kMovingClasses ?
       heap->AllocObject<true>(self, java_lang_Class_.Read(), new_length, visitor) :
       heap->AllocNonMovableObject<true>(self, java_lang_Class_.Read(), new_length, visitor);
   if (UNLIKELY(new_class == nullptr)) {
@@ -1049,7 +1058,7 @@
 
 // TODO: Move this to java_lang_Class.cc?
 ArtMethod* Class::GetDeclaredConstructor(
-    Thread* self, Handle<mirror::ObjectArray<mirror::Class>> args, PointerSize pointer_size) {
+    Thread* self, Handle<ObjectArray<Class>> args, PointerSize pointer_size) {
   for (auto& m : GetDirectMethods(pointer_size)) {
     // Skip <clinit> which is a static constructor, as well as non constructors.
     if (m.IsStatic() || !m.IsConstructor()) {
@@ -1068,7 +1077,7 @@
 
 uint32_t Class::Depth() {
   uint32_t depth = 0;
-  for (Class* klass = this; klass->GetSuperClass() != nullptr; klass = klass->GetSuperClass()) {
+  for (ObjPtr<Class> klass = this; klass->GetSuperClass() != nullptr; klass = klass->GetSuperClass()) {
     depth++;
   }
   return depth;
@@ -1081,10 +1090,11 @@
 }
 
 template <PointerSize kPointerSize, bool kTransactionActive>
-mirror::Method* Class::GetDeclaredMethodInternal(Thread* self,
-                                                 mirror::Class* klass,
-                                                 mirror::String* name,
-                                                 mirror::ObjectArray<mirror::Class>* args) {
+ObjPtr<Method> Class::GetDeclaredMethodInternal(
+    Thread* self,
+    ObjPtr<Class> klass,
+    ObjPtr<String> name,
+    ObjPtr<ObjectArray<Class>> args) {
   // Covariant return types permit the class to define multiple
   // methods with the same name and parameter types. Prefer to
   // return a non-synthetic method in such situations. We may
@@ -1099,12 +1109,12 @@
     return nullptr;
   }
   auto h_args = hs.NewHandle(args);
-  Handle<mirror::Class> h_klass = hs.NewHandle(klass);
+  Handle<Class> h_klass = hs.NewHandle(klass);
   ArtMethod* result = nullptr;
   for (auto& m : h_klass->GetDeclaredVirtualMethods(kPointerSize)) {
     auto* np_method = m.GetInterfaceMethodIfProxy(kPointerSize);
     // May cause thread suspension.
-    mirror::String* np_name = np_method->GetNameAsString(self);
+    ObjPtr<String> np_name = np_method->GetNameAsString(self);
     if (!np_name->Equals(h_method_name.Get()) || !np_method->EqualParameters(h_args)) {
       if (UNLIKELY(self->IsExceptionPending())) {
         return nullptr;
@@ -1113,7 +1123,7 @@
     }
     auto modifiers = m.GetAccessFlags();
     if ((modifiers & kSkipModifiers) == 0) {
-      return mirror::Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
+      return Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
     }
     if ((modifiers & kAccMiranda) == 0) {
       result = &m;  // Remember as potential result if it's not a miranda method.
@@ -1127,7 +1137,7 @@
       }
       auto* np_method = m.GetInterfaceMethodIfProxy(kPointerSize);
       // May cause thread suspension.
-      mirror::String* np_name = np_method->GetNameAsString(self);
+      ObjPtr<String> np_name = np_method->GetNameAsString(self);
       if (np_name == nullptr) {
         self->AssertPendingException();
         return nullptr;
@@ -1139,76 +1149,76 @@
         continue;
       }
       if ((modifiers & kSkipModifiers) == 0) {
-        return mirror::Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
+        return Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
       }
       // Direct methods cannot be miranda methods, so this potential result must be synthetic.
       result = &m;
     }
   }
   return result != nullptr
-      ? mirror::Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
+      ? Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
       : nullptr;
 }
 
 template
-mirror::Method* Class::GetDeclaredMethodInternal<PointerSize::k32, false>(
+ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k32, false>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::String* name,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<String> name,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Method* Class::GetDeclaredMethodInternal<PointerSize::k32, true>(
+ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k32, true>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::String* name,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<String> name,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Method* Class::GetDeclaredMethodInternal<PointerSize::k64, false>(
+ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k64, false>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::String* name,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<String> name,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Method* Class::GetDeclaredMethodInternal<PointerSize::k64, true>(
+ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k64, true>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::String* name,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<String> name,
+    ObjPtr<ObjectArray<Class>> args);
 
 template <PointerSize kPointerSize, bool kTransactionActive>
-mirror::Constructor* Class::GetDeclaredConstructorInternal(
+ObjPtr<Constructor> Class::GetDeclaredConstructorInternal(
     Thread* self,
-    mirror::Class* klass,
-    mirror::ObjectArray<mirror::Class>* args) {
+    ObjPtr<Class> klass,
+    ObjPtr<ObjectArray<Class>> args) {
   StackHandleScope<1> hs(self);
   ArtMethod* result = klass->GetDeclaredConstructor(self, hs.NewHandle(args), kPointerSize);
   return result != nullptr
-      ? mirror::Constructor::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
+      ? Constructor::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
       : nullptr;
 }
 
-// mirror::Constructor::CreateFromArtMethod<kTransactionActive>(self, result)
+// Constructor::CreateFromArtMethod<kTransactionActive>(self, result)
 
 template
-mirror::Constructor* Class::GetDeclaredConstructorInternal<PointerSize::k32, false>(
+ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k32, false>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Constructor* Class::GetDeclaredConstructorInternal<PointerSize::k32, true>(
+ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k32, true>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Constructor* Class::GetDeclaredConstructorInternal<PointerSize::k64, false>(
+ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k64, false>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<ObjectArray<Class>> args);
 template
-mirror::Constructor* Class::GetDeclaredConstructorInternal<PointerSize::k64, true>(
+ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k64, true>(
     Thread* self,
-    mirror::Class* klass,
-    mirror::ObjectArray<mirror::Class>* args);
+    ObjPtr<Class> klass,
+    ObjPtr<ObjectArray<Class>> args);
 
 int32_t Class::GetInnerClassFlags(Handle<Class> h_this, int32_t default_value) {
   if (h_this->IsProxyClass() || h_this->GetDexCache() == nullptr) {
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index 725939a..12ce014 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -56,7 +56,7 @@
 class Method;
 template <typename T> struct PACKED(8) DexCachePair;
 
-using StringDexCachePair = DexCachePair<mirror::String>;
+using StringDexCachePair = DexCachePair<String>;
 using StringDexCacheType = std::atomic<StringDexCachePair>;
 
 // C++ mirror of java.lang.Class
@@ -337,18 +337,7 @@
   // For array classes, where all the classes are final due to there being no sub-classes, an
   // Object[] may be assigned to by a String[] but a String[] may not be assigned to by other
   // types as the component is final.
-  bool CannotBeAssignedFromOtherTypes() REQUIRES_SHARED(Locks::mutator_lock_) {
-    if (!IsArrayClass()) {
-      return IsFinal();
-    } else {
-      Class* component = GetComponentType();
-      if (component->IsPrimitive()) {
-        return true;
-      } else {
-        return component->CannotBeAssignedFromOtherTypes();
-      }
-    }
-  }
+  bool CannotBeAssignedFromOtherTypes() REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Returns true if this class is the placeholder and should retire and
   // be replaced with a class with the right size for embedded imt/vtable.
@@ -473,7 +462,7 @@
            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   Class* GetComponentType() REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void SetComponentType(Class* new_component_type) REQUIRES_SHARED(Locks::mutator_lock_) {
+  void SetComponentType(ObjPtr<Class> new_component_type) REQUIRES_SHARED(Locks::mutator_lock_) {
     DCHECK(GetComponentType() == nullptr);
     DCHECK(new_component_type != nullptr);
     // Component type is invariant: use non-transactional mode without check.
@@ -508,7 +497,7 @@
   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   bool IsObjectArrayClass() REQUIRES_SHARED(Locks::mutator_lock_) {
-    mirror::Class* const component_type = GetComponentType<kVerifyFlags, kReadBarrierOption>();
+    ObjPtr<Class> const component_type = GetComponentType<kVerifyFlags, kReadBarrierOption>();
     return component_type != nullptr && !component_type->IsPrimitive();
   }
 
@@ -528,12 +517,12 @@
 
   // Creates a raw object instance but does not invoke the default constructor.
   template<bool kIsInstrumented, bool kCheckAddFinalizer = true>
-  ALWAYS_INLINE Object* Alloc(Thread* self, gc::AllocatorType allocator_type)
+  ALWAYS_INLINE ObjPtr<Object> Alloc(Thread* self, gc::AllocatorType allocator_type)
       REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
 
-  Object* AllocObject(Thread* self)
+  ObjPtr<Object> AllocObject(Thread* self)
       REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
-  Object* AllocNonMovableObject(Thread* self)
+  ObjPtr<Object> AllocNonMovableObject(Thread* self)
       REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
 
   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
@@ -638,11 +627,14 @@
   // Can this class access a resolved method?
   // Note that access to methods's class is checked and this may require looking up the class
   // referenced by the MethodId in the DexFile in case the declaring class is inaccessible.
-  bool CanAccessResolvedMethod(Class* access_to, ArtMethod* resolved_method,
-                               DexCache* dex_cache, uint32_t method_idx)
+  bool CanAccessResolvedMethod(ObjPtr<Class> access_to,
+                               ArtMethod* resolved_method,
+                               ObjPtr<DexCache> dex_cache,
+                               uint32_t method_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
   template <InvokeType throw_invoke_type>
-  bool CheckResolvedMethodAccess(Class* access_to, ArtMethod* resolved_method,
+  bool CheckResolvedMethodAccess(ObjPtr<Class> access_to,
+                                 ArtMethod* resolved_method,
                                  uint32_t method_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -661,11 +653,12 @@
 
   // Get first common super class. It will never return null.
   // `This` and `klass` must be classes.
-  Class* GetCommonSuperClass(Handle<Class> klass) REQUIRES_SHARED(Locks::mutator_lock_);
+  ObjPtr<Class> GetCommonSuperClass(Handle<Class> klass) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void SetSuperClass(Class* new_super_class) REQUIRES_SHARED(Locks::mutator_lock_) {
+  void SetSuperClass(ObjPtr<Class> new_super_class) REQUIRES_SHARED(Locks::mutator_lock_) {
     // Super class is assigned once, except during class linker initialization.
-    Class* old_super_class = GetFieldObject<Class>(OFFSET_OF_OBJECT_MEMBER(Class, super_class_));
+    ObjPtr<Class> old_super_class =
+        GetFieldObject<Class>(OFFSET_OF_OBJECT_MEMBER(Class, super_class_));
     DCHECK(old_super_class == nullptr || old_super_class == new_super_class);
     DCHECK(new_super_class != nullptr);
     SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, super_class_), new_super_class);
@@ -681,7 +674,7 @@
 
   ClassLoader* GetClassLoader() ALWAYS_INLINE REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void SetClassLoader(ClassLoader* new_cl) REQUIRES_SHARED(Locks::mutator_lock_);
+  void SetClassLoader(ObjPtr<ClassLoader> new_cl) REQUIRES_SHARED(Locks::mutator_lock_);
 
   static MemberOffset DexCacheOffset() {
     return MemberOffset(OFFSETOF_MEMBER(Class, dex_cache_));
@@ -699,7 +692,7 @@
   DexCache* GetDexCache() REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Also updates the dex_cache_strings_ variable from new_dex_cache.
-  void SetDexCache(DexCache* new_dex_cache) REQUIRES_SHARED(Locks::mutator_lock_);
+  void SetDexCache(ObjPtr<DexCache> new_dex_cache) REQUIRES_SHARED(Locks::mutator_lock_);
 
   ALWAYS_INLINE IterationRange<StrideIterator<ArtMethod>> GetDirectMethods(PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
@@ -753,15 +746,16 @@
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   template <PointerSize kPointerSize, bool kTransactionActive>
-  static Method* GetDeclaredMethodInternal(Thread* self,
-                                           mirror::Class* klass,
-                                           mirror::String* name,
-                                           mirror::ObjectArray<mirror::Class>* args)
+  static ObjPtr<Method> GetDeclaredMethodInternal(Thread* self,
+                                                  ObjPtr<Class> klass,
+                                                  ObjPtr<String> name,
+                                                  ObjPtr<ObjectArray<Class>> args)
       REQUIRES_SHARED(Locks::mutator_lock_);
+
   template <PointerSize kPointerSize, bool kTransactionActive>
-  static Constructor* GetDeclaredConstructorInternal(Thread* self,
-                                                     mirror::Class* klass,
-                                                     mirror::ObjectArray<mirror::Class>* args)
+  static ObjPtr<Constructor> GetDeclaredConstructorInternal(Thread* self,
+                                                            ObjPtr<Class> klass,
+                                                            ObjPtr<ObjectArray<Class>> args)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
@@ -894,69 +888,86 @@
   ArtMethod* FindVirtualMethodForVirtualOrInterface(ArtMethod* method, PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindInterfaceMethod(const StringPiece& name, const StringPiece& signature,
+  ArtMethod* FindInterfaceMethod(const StringPiece& name,
+                                 const StringPiece& signature,
                                  PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindInterfaceMethod(const StringPiece& name, const Signature& signature,
+  ArtMethod* FindInterfaceMethod(const StringPiece& name,
+                                 const Signature& signature,
                                  PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindInterfaceMethod(const DexCache* dex_cache, uint32_t dex_method_idx,
+  ArtMethod* FindInterfaceMethod(ObjPtr<DexCache> dex_cache,
+                                 uint32_t dex_method_idx,
                                  PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredDirectMethod(const StringPiece& name, const StringPiece& signature,
+  ArtMethod* FindDeclaredDirectMethod(const StringPiece& name,
+                                      const StringPiece& signature,
                                       PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredDirectMethod(const StringPiece& name, const Signature& signature,
+  ArtMethod* FindDeclaredDirectMethod(const StringPiece& name,
+                                      const Signature& signature,
                                       PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredDirectMethod(const DexCache* dex_cache, uint32_t dex_method_idx,
+  ArtMethod* FindDeclaredDirectMethod(ObjPtr<DexCache> dex_cache,
+                                      uint32_t dex_method_idx,
                                       PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDirectMethod(const StringPiece& name, const StringPiece& signature,
+  ArtMethod* FindDirectMethod(const StringPiece& name,
+                              const StringPiece& signature,
                               PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDirectMethod(const StringPiece& name, const Signature& signature,
+  ArtMethod* FindDirectMethod(const StringPiece& name,
+                              const Signature& signature,
                               PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDirectMethod(const DexCache* dex_cache, uint32_t dex_method_idx,
+  ArtMethod* FindDirectMethod(ObjPtr<DexCache> dex_cache,
+                              uint32_t dex_method_idx,
                               PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredVirtualMethod(const StringPiece& name, const StringPiece& signature,
+  ArtMethod* FindDeclaredVirtualMethod(const StringPiece& name,
+                                       const StringPiece& signature,
                                        PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredVirtualMethod(const StringPiece& name, const Signature& signature,
+  ArtMethod* FindDeclaredVirtualMethod(const StringPiece& name,
+                                       const Signature& signature,
                                        PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredVirtualMethod(const DexCache* dex_cache, uint32_t dex_method_idx,
+  ArtMethod* FindDeclaredVirtualMethod(ObjPtr<DexCache> dex_cache,
+                                       uint32_t dex_method_idx,
                                        PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredVirtualMethodByName(const StringPiece& name, PointerSize pointer_size)
+  ArtMethod* FindDeclaredVirtualMethodByName(const StringPiece& name,
+                                             PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindDeclaredDirectMethodByName(const StringPiece& name, PointerSize pointer_size)
+  ArtMethod* FindDeclaredDirectMethodByName(const StringPiece& name,
+                                            PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindVirtualMethod(const StringPiece& name, const StringPiece& signature,
+  ArtMethod* FindVirtualMethod(const StringPiece& name,
+                               const StringPiece& signature,
                                PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindVirtualMethod(const StringPiece& name, const Signature& signature,
+  ArtMethod* FindVirtualMethod(const StringPiece& name,
+                               const Signature& signature,
                                PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtMethod* FindVirtualMethod(const DexCache* dex_cache, uint32_t dex_method_idx,
+  ArtMethod* FindVirtualMethod(ObjPtr<DexCache> dex_cache,
+                               uint32_t dex_method_idx,
                                PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -976,7 +987,8 @@
            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   ALWAYS_INLINE IfTable* GetIfTable() REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ALWAYS_INLINE void SetIfTable(IfTable* new_iftable) REQUIRES_SHARED(Locks::mutator_lock_);
+  ALWAYS_INLINE void SetIfTable(ObjPtr<IfTable> new_iftable)
+      REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Get instance fields of the class (See also GetSFields).
   LengthPrefixedArray<ArtField>* GetIFieldsPtr() REQUIRES_SHARED(Locks::mutator_lock_);
@@ -1077,32 +1089,34 @@
 
   // Finds the given instance field in this class or a superclass, only searches classes that
   // have the same dex cache.
-  ArtField* FindInstanceField(const DexCache* dex_cache, uint32_t dex_field_idx)
+  ArtField* FindInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   ArtField* FindDeclaredInstanceField(const StringPiece& name, const StringPiece& type)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtField* FindDeclaredInstanceField(const DexCache* dex_cache, uint32_t dex_field_idx)
+  ArtField* FindDeclaredInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Finds the given static field in this class or a superclass.
-  static ArtField* FindStaticField(Thread* self, Handle<Class> klass, const StringPiece& name,
+  static ArtField* FindStaticField(Thread* self,
+                                   Handle<Class> klass,
+                                   const StringPiece& name,
                                    const StringPiece& type)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Finds the given static field in this class or superclass, only searches classes that
   // have the same dex cache.
   static ArtField* FindStaticField(Thread* self,
-                                   Class* klass,
-                                   const DexCache* dex_cache,
+                                   ObjPtr<Class> klass,
+                                   ObjPtr<DexCache> dex_cache,
                                    uint32_t dex_field_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   ArtField* FindDeclaredStaticField(const StringPiece& name, const StringPiece& type)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  ArtField* FindDeclaredStaticField(const DexCache* dex_cache, uint32_t dex_field_idx)
+  ArtField* FindDeclaredStaticField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   pid_t GetClinitThreadId() REQUIRES_SHARED(Locks::mutator_lock_) {
@@ -1148,7 +1162,7 @@
   }
 
   // Can't call this SetClass or else gets called instead of Object::SetClass in places.
-  static void SetClassClass(Class* java_lang_Class) REQUIRES_SHARED(Locks::mutator_lock_);
+  static void SetClassClass(ObjPtr<Class> java_lang_Class) REQUIRES_SHARED(Locks::mutator_lock_);
   static void ResetClass();
   static void VisitRoots(RootVisitor* visitor)
       REQUIRES_SHARED(Locks::mutator_lock_);
@@ -1178,8 +1192,9 @@
 
   uint16_t GetDirectInterfaceTypeIdx(uint32_t idx) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  static mirror::Class* GetDirectInterface(Thread* self, Handle<mirror::Class> klass,
-                                           uint32_t idx)
+  static ObjPtr<Class> GetDirectInterface(Thread* self,
+                                          Handle<Class> klass,
+                                          uint32_t idx)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   const char* GetSourceFile() REQUIRES_SHARED(Locks::mutator_lock_);
@@ -1194,7 +1209,9 @@
   void AssertInitializedOrInitializingInThread(Thread* self)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  Class* CopyOf(Thread* self, int32_t new_length, ImTable* imt,
+  Class* CopyOf(Thread* self,
+                int32_t new_length,
+                ImTable* imt,
                 PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
 
@@ -1218,8 +1235,9 @@
   }
 
   // May cause thread suspension due to EqualParameters.
-  ArtMethod* GetDeclaredConstructor(
-      Thread* self, Handle<mirror::ObjectArray<mirror::Class>> args, PointerSize pointer_size)
+  ArtMethod* GetDeclaredConstructor(Thread* self,
+                                    Handle<ObjectArray<Class>> args,
+                                    PointerSize pointer_size)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   static int32_t GetInnerClassFlags(Handle<Class> h_this, int32_t default_value)
@@ -1232,7 +1250,7 @@
     explicit InitializeClassVisitor(uint32_t class_size) : class_size_(class_size) {
     }
 
-    void operator()(ObjPtr<mirror::Object> obj, size_t usable_size) const
+    void operator()(ObjPtr<Object> obj, size_t usable_size) const
         REQUIRES_SHARED(Locks::mutator_lock_);
 
    private:
@@ -1277,14 +1295,14 @@
   template <VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
             ReadBarrierOption kReadBarrierOption = kWithReadBarrier,
             typename Visitor>
-  void FixupNativePointers(mirror::Class* dest, PointerSize pointer_size, const Visitor& visitor)
+  void FixupNativePointers(Class* dest, PointerSize pointer_size, const Visitor& visitor)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
  private:
   ALWAYS_INLINE void SetMethodsPtrInternal(LengthPrefixedArray<ArtMethod>* new_methods)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void SetVerifyError(Object* klass) REQUIRES_SHARED(Locks::mutator_lock_);
+  void SetVerifyError(ObjPtr<Object> klass) REQUIRES_SHARED(Locks::mutator_lock_);
 
   template <bool throw_on_failure, bool use_referrers_cache>
   bool ResolvedFieldAccessTest(ObjPtr<Class> access_to,
@@ -1300,7 +1318,7 @@
                                 ObjPtr<DexCache> dex_cache)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  bool Implements(Class* klass) REQUIRES_SHARED(Locks::mutator_lock_);
+  bool Implements(ObjPtr<Class> klass) REQUIRES_SHARED(Locks::mutator_lock_);
   bool IsArrayAssignableFromArray(ObjPtr<Class> klass) REQUIRES_SHARED(Locks::mutator_lock_);
   bool IsAssignableFromArray(ObjPtr<Class> klass) REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -1333,7 +1351,7 @@
             VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
             ReadBarrierOption kReadBarrierOption = kWithReadBarrier,
             typename Visitor>
-  void VisitReferences(mirror::Class* klass, const Visitor& visitor)
+  void VisitReferences(ObjPtr<Class> klass, const Visitor& visitor)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   // 'Class' Object Fields
diff --git a/runtime/mirror/field-inl.h b/runtime/mirror/field-inl.h
index 445f23f..940e824 100644
--- a/runtime/mirror/field-inl.h
+++ b/runtime/mirror/field-inl.h
@@ -48,7 +48,7 @@
       self->ClearException();
     }
   }
-  auto ret = hs.NewHandle(static_cast<Field*>(StaticClass()->AllocObject(self)));
+  auto ret = hs.NewHandle(static_cast<Field*>(StaticClass()->AllocObject(self).Ptr()));
   if (UNLIKELY(ret.Get() == nullptr)) {
     self->AssertPendingOOMException();
     return nullptr;
diff --git a/runtime/mirror/method.cc b/runtime/mirror/method.cc
index 71bac7e..7ddadda 100644
--- a/runtime/mirror/method.cc
+++ b/runtime/mirror/method.cc
@@ -54,12 +54,12 @@
 template <PointerSize kPointerSize, bool kTransactionActive>
 Method* Method::CreateFromArtMethod(Thread* self, ArtMethod* method) {
   DCHECK(!method->IsConstructor()) << PrettyMethod(method);
-  auto* ret = down_cast<Method*>(StaticClass()->AllocObject(self));
+  ObjPtr<Method> ret = ObjPtr<Method>::DownCast(StaticClass()->AllocObject(self));
   if (LIKELY(ret != nullptr)) {
-    static_cast<Executable*>(ret)->
+    ObjPtr<Executable>(ret)->
         CreateFromArtMethod<kPointerSize, kTransactionActive>(method);
   }
-  return ret;
+  return ret.Ptr();
 }
 
 template Method* Method::CreateFromArtMethod<PointerSize::k32, false>(Thread* self,
@@ -106,12 +106,12 @@
 template <PointerSize kPointerSize, bool kTransactionActive>
 Constructor* Constructor::CreateFromArtMethod(Thread* self, ArtMethod* method) {
   DCHECK(method->IsConstructor()) << PrettyMethod(method);
-  auto* ret = down_cast<Constructor*>(StaticClass()->AllocObject(self));
+  ObjPtr<Constructor> ret = ObjPtr<Constructor>::DownCast(StaticClass()->AllocObject(self));
   if (LIKELY(ret != nullptr)) {
-    static_cast<Executable*>(ret)->
+    ObjPtr<Executable>(ret)->
         CreateFromArtMethod<kPointerSize, kTransactionActive>(method);
   }
-  return ret;
+  return ret.Ptr();
 }
 
 template Constructor* Constructor::CreateFromArtMethod<PointerSize::k32, false>(
diff --git a/runtime/mirror/method_type.cc b/runtime/mirror/method_type.cc
index ba6ea5e..0b52931 100644
--- a/runtime/mirror/method_type.cc
+++ b/runtime/mirror/method_type.cc
@@ -29,7 +29,7 @@
                                        Handle<ObjectArray<Class>> param_types) {
   StackHandleScope<1> hs(self);
   Handle<mirror::MethodType> mt(
-      hs.NewHandle(static_cast<MethodType*>(StaticClass()->AllocObject(self))));
+      hs.NewHandle(ObjPtr<MethodType>::DownCast(StaticClass()->AllocObject(self))));
 
   // TODO: Do we ever create a MethodType during a transaction ? There doesn't
   // seem like a good reason to do a polymorphic invoke that results in the
diff --git a/runtime/mirror/object_test.cc b/runtime/mirror/object_test.cc
index 062afd3..60e2bf8 100644
--- a/runtime/mirror/object_test.cc
+++ b/runtime/mirror/object_test.cc
@@ -139,10 +139,10 @@
   ASSERT_TRUE(oa->GetClass() != nullptr);
   Handle<mirror::Class> klass(hs.NewHandle(oa->GetClass()));
   ASSERT_EQ(2U, klass->NumDirectInterfaces());
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "Ljava/lang/Cloneable;"),
-            mirror::Class::GetDirectInterface(soa.Self(), klass, 0));
-  EXPECT_EQ(class_linker_->FindSystemClass(soa.Self(), "Ljava/io/Serializable;"),
-            mirror::Class::GetDirectInterface(soa.Self(), klass, 1));
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "Ljava/lang/Cloneable;"),
+                    mirror::Class::GetDirectInterface(soa.Self(), klass, 0));
+  EXPECT_OBJ_PTR_EQ(class_linker_->FindSystemClass(soa.Self(), "Ljava/io/Serializable;"),
+                    mirror::Class::GetDirectInterface(soa.Self(), klass, 1));
 }
 
 TEST_F(ObjectTest, AllocArray) {
diff --git a/runtime/mirror/stack_trace_element.cc b/runtime/mirror/stack_trace_element.cc
index 96f6a53..e2050cc 100644
--- a/runtime/mirror/stack_trace_element.cc
+++ b/runtime/mirror/stack_trace_element.cc
@@ -42,8 +42,8 @@
 StackTraceElement* StackTraceElement::Alloc(Thread* self, Handle<String> declaring_class,
                                             Handle<String> method_name, Handle<String> file_name,
                                             int32_t line_number) {
-  StackTraceElement* trace =
-      down_cast<StackTraceElement*>(GetStackTraceElement()->AllocObject(self));
+  ObjPtr<StackTraceElement> trace =
+      ObjPtr<StackTraceElement>::DownCast(GetStackTraceElement()->AllocObject(self));
   if (LIKELY(trace != nullptr)) {
     if (Runtime::Current()->IsActiveTransaction()) {
       trace->Init<true>(declaring_class, method_name, file_name, line_number);
@@ -51,7 +51,7 @@
       trace->Init<false>(declaring_class, method_name, file_name, line_number);
     }
   }
-  return trace;
+  return trace.Ptr();
 }
 
 template<bool kTransactionActive>