runtime/gc/collector/semi_space-inl.h

/*
 * Copyright (C) 2013 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_GC_COLLECTOR_SEMI_SPACE_INL_H_
#define ART_RUNTIME_GC_COLLECTOR_SEMI_SPACE_INL_H_

#include "semi_space.h"

#include "gc/accounting/heap_bitmap.h"
#include "mirror/object-inl.h"

namespace art {
namespace gc {
namespace collector {

inline mirror::Object* SemiSpace::GetForwardingAddressInFromSpace(mirror::Object* obj) const {
  DCHECK(from_space_->HasAddress(obj));
  LockWord lock_word = obj->GetLockWord();
  if (lock_word.GetState() != LockWord::kForwardingAddress) {
    return nullptr;
  }
  return reinterpret_cast<mirror::Object*>(lock_word.ForwardingAddress());
}

// Used to mark and copy objects. Any newly-marked objects who are in the from space get moved to
// the to-space and have their forward address updated. Objects which have been newly marked are
// pushed on the mark stack.
template<bool kPoisonReferences>
inline void SemiSpace::MarkObject(
    mirror::ObjectReference<kPoisonReferences, mirror::Object>* obj_ptr) {
  mirror::Object* obj = obj_ptr->AsMirrorPtr();
  if (obj == nullptr) {
    return;
  }
  if (kUseBakerOrBrooksReadBarrier) {
    // Verify all the objects have the correct forward pointer installed.
    obj->AssertReadBarrierPointer();
  }
  if (!immune_region_.ContainsObject(obj)) {
    if (from_space_->HasAddress(obj)) {
      mirror::Object* forward_address = GetForwardingAddressInFromSpace(obj);
      // If the object has already been moved, return the new forward address.
      if (forward_address == nullptr) {
        forward_address = MarkNonForwardedObject(obj);
        DCHECK(forward_address != nullptr);
        // Make sure to only update the forwarding address AFTER you copy the object so that the
        // monitor word doesn't get stomped over.
        obj->SetLockWord(LockWord::FromForwardingAddress(
            reinterpret_cast<size_t>(forward_address)));
        // Push the object onto the mark stack for later processing.
        MarkStackPush(forward_address);
      }
      obj_ptr->Assign(forward_address);
    } else {
      accounting::ContinuousSpaceBitmap* object_bitmap =
          heap_->GetMarkBitmap()->GetContinuousSpaceBitmap(obj);
      if (LIKELY(object_bitmap != nullptr)) {
        if (generational_) {
          // If a bump pointer space only collection, we should not
          // reach here as we don't/won't mark the objects in the
          // non-moving space (except for the promoted objects.)  Note
          // the non-moving space is added to the immune space.
          DCHECK(whole_heap_collection_);
        }
        if (!object_bitmap->Set(obj)) {
          // This object was not previously marked.
          MarkStackPush(obj);
        }
      } else {
        CHECK(!to_space_->HasAddress(obj)) << "Marking " << obj << " in to_space_";
        if (MarkLargeObject(obj)) {
          MarkStackPush(obj);
        }
      }
    }
  }
}

}  // namespace collector
}  // namespace gc
}  // namespace art

#endif  // ART_RUNTIME_GC_COLLECTOR_SEMI_SPACE_INL_H_