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/*
* Copyright (C) 2016 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_BLOCK_BUILDER_H_
#define ART_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_
#include "base/scoped_arena_allocator.h"
#include "base/scoped_arena_containers.h"
#include "dex/code_item_accessors.h"
#include "dex/dex_file.h"
#include "nodes.h"
namespace art {
class HBasicBlockBuilder : public ValueObject {
public:
HBasicBlockBuilder(HGraph* graph,
const DexFile* const dex_file,
const CodeItemDebugInfoAccessor& accessor,
ScopedArenaAllocator* local_allocator);
// Creates basic blocks in `graph_` at branch target dex_pc positions of the
// `code_item_`. Blocks are connected but left unpopulated with instructions.
// TryBoundary blocks are inserted at positions where control-flow enters/
// exits a try block.
bool Build();
// Creates basic blocks in `graph_` for compiling an intrinsic.
void BuildIntrinsic();
size_t GetNumberOfBranches() const { return number_of_branches_; }
HBasicBlock* GetBlockAt(uint32_t dex_pc) const { return branch_targets_[dex_pc]; }
size_t GetQuickenIndex(uint32_t dex_pc) const;
private:
// Creates a basic block starting at given `dex_pc`.
HBasicBlock* MaybeCreateBlockAt(uint32_t dex_pc);
// Creates a basic block for bytecode instructions at `semantic_dex_pc` and
// stores it under the `store_dex_pc` key. This is used when multiple blocks
// share the same semantic dex_pc, e.g. when building switch decision trees.
HBasicBlock* MaybeCreateBlockAt(uint32_t semantic_dex_pc, uint32_t store_dex_pc);
bool CreateBranchTargets();
void ConnectBasicBlocks();
void InsertTryBoundaryBlocks();
// To ensure branches with negative offsets can always OSR jump to compiled
// code, we insert synthesized loops before each block that is the target of a
// negative branch.
void InsertSynthesizedLoopsForOsr();
// Helper method which decides whether `catch_block` may have live normal
// predecessors and thus whether a synthetic catch block needs to be created
// to avoid mixing normal and exceptional predecessors.
// Should only be called during InsertTryBoundaryBlocks on blocks at catch
// handler dex_pcs.
bool MightHaveLiveNormalPredecessors(HBasicBlock* catch_block);
ArenaAllocator* const allocator_;
HGraph* const graph_;
const DexFile* const dex_file_;
CodeItemDataAccessor code_item_accessor_; // null code item for intrinsic graph.
ScopedArenaAllocator* const local_allocator_;
ScopedArenaVector<HBasicBlock*> branch_targets_;
ScopedArenaVector<HBasicBlock*> throwing_blocks_;
size_t number_of_branches_;
// A table to quickly find the quicken index for the first instruction of a basic block.
ScopedArenaSafeMap<uint32_t, uint32_t> quicken_index_for_dex_pc_;
static constexpr size_t kDefaultNumberOfThrowingBlocks = 2u;
DISALLOW_COPY_AND_ASSIGN(HBasicBlockBuilder);
};
} // namespace art
#endif // ART_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_