runtime/mirror/object-refvisitor-inl.h

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ART_RUNTIME_MIRROR_OBJECT_REFVISITOR_INL_H_
#define ART_RUNTIME_MIRROR_OBJECT_REFVISITOR_INL_H_

#include "object-inl.h"

#include "class-refvisitor-inl.h"
#include "class_loader-inl.h"
#include "dex_cache-inl.h"

namespace art HIDDEN {
namespace mirror {

template <VerifyObjectFlags kVerifyFlags,
          ReadBarrierOption kReadBarrierOption>
static void CheckNoReferenceField(ObjPtr<mirror::Class> klass)
    REQUIRES_SHARED(art::Locks::mutator_lock_) {
  if (!kIsDebugBuild) {
    return;
  }
  CHECK(!klass->IsClassClass<kVerifyFlags>());
  CHECK((!klass->IsObjectArrayClass<kVerifyFlags, kReadBarrierOption>()));
  // String still has instance fields for reflection purposes but these don't exist in
  // actual string instances.
  if (!klass->IsStringClass<kVerifyFlags>()) {
    size_t total_reference_instance_fields = 0;
    ObjPtr<Class> super_class = klass;
    do {
      total_reference_instance_fields +=
          super_class->NumReferenceInstanceFields<kVerifyFlags>();
      super_class = super_class->GetSuperClass<kVerifyFlags, kReadBarrierOption>();
    } while (super_class != nullptr);
    // The only reference field should be the object's class.
    CHECK_EQ(total_reference_instance_fields, 1u);
  }
}

template <VerifyObjectFlags kVerifyFlags>
static void CheckNormalClass(ObjPtr<mirror::Class> klass)
    REQUIRES_SHARED(art::Locks::mutator_lock_) {
  DCHECK(!klass->IsVariableSize<kVerifyFlags>());
  DCHECK(!klass->IsClassClass<kVerifyFlags>());
  DCHECK(!klass->IsStringClass<kVerifyFlags>());
  DCHECK(!klass->IsClassLoaderClass<kVerifyFlags>());
  DCHECK(!klass->IsArrayClass<kVerifyFlags>());
}

template <bool kVisitNativeRoots,
          VerifyObjectFlags kVerifyFlags,
          ReadBarrierOption kReadBarrierOption,
          typename Visitor,
          typename JavaLangRefVisitor>
inline void Object::FastVisitReferences(const Visitor& visitor,
                                        const JavaLangRefVisitor& ref_visitor) {
  visitor(this, ClassOffset(), /* is_static= */ false);
  ObjPtr<Class> klass = GetClass<kVerifyFlags, kReadBarrierOption>();
  const uint32_t class_flags = klass->GetClassFlags<kVerifyNone>();
  DCHECK_NE(class_flags & (kClassFlagNormal | kClassFlagNoReferenceFields),
            kClassFlagNormal | kClassFlagNoReferenceFields);
  if ((class_flags & kClassFlagNoReferenceFields) != 0) {
    CheckNoReferenceField<kVerifyFlags, kReadBarrierOption>(klass);
    return;
  }
  DCHECK(!klass->IsStringClass<kVerifyFlags>());

  if ((class_flags & kClassFlagObjectArray) != 0) {
    DCHECK((klass->IsObjectArrayClass<kVerifyFlags, kReadBarrierOption>()));
    AsObjectArray<mirror::Object, kVerifyNone>()->VisitReferences(visitor);
    return;
  }

  VisitInstanceFieldsReferences<kVerifyFlags, kReadBarrierOption>(klass, visitor);
  // Record with no references will return from previous if block.
  if ((class_flags & (kClassFlagNormal | kClassFlagRecord)) != 0) {
    CheckNormalClass<kVerifyFlags>(klass);
    DCHECK(klass->IsInstantiableNonArray()) << klass->PrettyDescriptor();
    return;
  }

  if ((class_flags & kClassFlagClass) != 0) {
    DCHECK(klass->IsClassClass<kVerifyFlags>());
    DCHECK(klass->IsInstantiableNonArray()) << klass->PrettyDescriptor();
    ObjPtr<Class> as_klass = AsClass<kVerifyNone>();
    as_klass->VisitReferences<kVisitNativeRoots,
                              /*kVisitInstanceFieldsRefs=*/false,
                              kVerifyFlags,
                              kReadBarrierOption>(klass, visitor);
    return;
  }

  if ((class_flags & kClassFlagReference) != 0) {
    DCHECK(klass->IsInstantiableNonArray()) << klass->PrettyDescriptor();
    ref_visitor(klass, AsReference<kVerifyFlags, kReadBarrierOption>());
    return;
  }

  if (!kVisitNativeRoots) {
    return;
  }

  if (UNLIKELY((class_flags & kClassFlagDexCache) != 0)) {
    DCHECK(klass->IsInstantiableNonArray()) << klass->PrettyDescriptor();
    DCHECK(klass->IsDexCacheClass<kVerifyFlags>());
    ObjPtr<mirror::DexCache> const dex_cache = AsDexCache<kVerifyFlags, kReadBarrierOption>();
    auto should_visit = [](void* ptr) { return ptr != nullptr; };
    dex_cache->VisitNativeRoots<kVerifyFlags, kReadBarrierOption>(visitor, should_visit);
    return;
  }

  if (UNLIKELY((class_flags & kClassFlagClassLoader) != 0)) {
    DCHECK(klass->IsInstantiableNonArray()) << klass->PrettyDescriptor();
    DCHECK(klass->IsClassLoaderClass<kVerifyFlags>());
    ObjPtr<mirror::ClassLoader> const class_loader =
        AsClassLoader<kVerifyFlags, kReadBarrierOption>();
    class_loader->VisitNativeRoots<kVerifyFlags>(visitor);
    return;
  }

  LOG(FATAL) << "Unexpected class flags: " << std::hex << class_flags
            << " for " << klass->PrettyClass();
}

}  // namespace mirror
}  // namespace art

#endif  // ART_RUNTIME_MIRROR_OBJECT_REFVISITOR_INL_H_