57 lines
2.0 KiB
C++
57 lines
2.0 KiB
C++
/*
|
|
* Copyright (C) 2022 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_COMPILER_OPTIMIZING_WRITE_BARRIER_ELIMINATION_H_
|
|
#define ART_COMPILER_OPTIMIZING_WRITE_BARRIER_ELIMINATION_H_
|
|
|
|
#include "base/macros.h"
|
|
#include "optimization.h"
|
|
|
|
namespace art HIDDEN {
|
|
|
|
// Eliminates unnecessary write barriers from InstanceFieldSet, StaticFieldSet, and ArraySet.
|
|
//
|
|
// We can eliminate redundant write barriers as we don't need several for the same receiver. For
|
|
// example:
|
|
// MyObject o;
|
|
// o.inner_obj = io;
|
|
// o.inner_obj2 = io2;
|
|
// o.inner_obj3 = io3;
|
|
// We can keep the write barrier for `inner_obj` and remove the other two.
|
|
//
|
|
// In order to do this, we set the WriteBarrierKind of the instruction. The instruction's kind are
|
|
// set to kEmitNoNullCheck (if this write barrier coalesced other write barriers, we don't want to
|
|
// perform the null check optimization), or to kDontEmit (if the write barrier as a whole is not
|
|
// needed).
|
|
class WriteBarrierElimination : public HOptimization {
|
|
public:
|
|
WriteBarrierElimination(HGraph* graph,
|
|
OptimizingCompilerStats* stats,
|
|
const char* name = kWBEPassName)
|
|
: HOptimization(graph, name, stats) {}
|
|
|
|
bool Run() override;
|
|
|
|
static constexpr const char* kWBEPassName = "write_barrier_elimination";
|
|
|
|
private:
|
|
DISALLOW_COPY_AND_ASSIGN(WriteBarrierElimination);
|
|
};
|
|
|
|
} // namespace art
|
|
|
|
#endif // ART_COMPILER_OPTIMIZING_WRITE_BARRIER_ELIMINATION_H_
|