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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_GC_COLLECTOR_SEMI_SPACE_INL_H_
     18 #define ART_RUNTIME_GC_COLLECTOR_SEMI_SPACE_INL_H_
     19 
     20 #include "semi_space.h"
     21 
     22 #include "gc/accounting/heap_bitmap.h"
     23 #include "mirror/object-inl.h"
     24 
     25 namespace art {
     26 namespace gc {
     27 namespace collector {
     28 
     29 class BitmapSetSlowPathVisitor {
     30  public:
     31   explicit BitmapSetSlowPathVisitor(SemiSpace* semi_space) : semi_space_(semi_space) {
     32   }
     33 
     34   void operator()(const mirror::Object* obj) const {
     35     CHECK(!semi_space_->to_space_->HasAddress(obj)) << "Marking " << obj << " in to_space_";
     36     // Marking a large object, make sure its aligned as a sanity check.
     37     CHECK(IsAligned<kPageSize>(obj));
     38   }
     39 
     40  private:
     41   SemiSpace* const semi_space_;
     42 };
     43 
     44 inline mirror::Object* SemiSpace::GetForwardingAddressInFromSpace(mirror::Object* obj) const {
     45   DCHECK(from_space_->HasAddress(obj));
     46   LockWord lock_word = obj->GetLockWord(false);
     47   if (lock_word.GetState() != LockWord::kForwardingAddress) {
     48     return nullptr;
     49   }
     50   return reinterpret_cast<mirror::Object*>(lock_word.ForwardingAddress());
     51 }
     52 
     53 // Used to mark and copy objects. Any newly-marked objects who are in the from space Get moved to
     54 // the to-space and have their forward address updated. Objects which have been newly marked are
     55 // pushed on the mark stack.
     56 template<bool kPoisonReferences>
     57 inline void SemiSpace::MarkObject(
     58     mirror::ObjectReference<kPoisonReferences, mirror::Object>* obj_ptr) {
     59   mirror::Object* obj = obj_ptr->AsMirrorPtr();
     60   if (obj == nullptr) {
     61     return;
     62   }
     63   if (kUseBakerOrBrooksReadBarrier) {
     64     // Verify all the objects have the correct forward pointer installed.
     65     obj->AssertReadBarrierPointer();
     66   }
     67   if (from_space_->HasAddress(obj)) {
     68     mirror::Object* forward_address = GetForwardingAddressInFromSpace(obj);
     69     // If the object has already been moved, return the new forward address.
     70     if (UNLIKELY(forward_address == nullptr)) {
     71       forward_address = MarkNonForwardedObject(obj);
     72       DCHECK(forward_address != nullptr);
     73       // Make sure to only update the forwarding address AFTER you copy the object so that the
     74       // monitor word doesn't Get stomped over.
     75       obj->SetLockWord(
     76           LockWord::FromForwardingAddress(reinterpret_cast<size_t>(forward_address)), false);
     77       // Push the object onto the mark stack for later processing.
     78       MarkStackPush(forward_address);
     79     }
     80     obj_ptr->Assign(forward_address);
     81   } else if (!collect_from_space_only_ && !immune_region_.ContainsObject(obj)) {
     82     BitmapSetSlowPathVisitor visitor(this);
     83     if (!mark_bitmap_->Set(obj, visitor)) {
     84       // This object was not previously marked.
     85       MarkStackPush(obj);
     86     }
     87   }
     88 }
     89 
     90 }  // namespace collector
     91 }  // namespace gc
     92 }  // namespace art
     93 
     94 #endif  // ART_RUNTIME_GC_COLLECTOR_SEMI_SPACE_INL_H_
     95