David Brazdil | 86ea7ee | 2016-02-16 09:26:07 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_ |
| 18 | #define ART_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_ |
| 19 | |
| 20 | #include "base/arena_containers.h" |
| 21 | #include "base/arena_object.h" |
| 22 | #include "dex_file.h" |
| 23 | #include "nodes.h" |
| 24 | |
| 25 | namespace art { |
| 26 | |
| 27 | class HBasicBlockBuilder : public ValueObject { |
| 28 | public: |
| 29 | HBasicBlockBuilder(HGraph* graph, |
| 30 | const DexFile* const dex_file, |
| 31 | const DexFile::CodeItem& code_item) |
| 32 | : arena_(graph->GetArena()), |
| 33 | graph_(graph), |
| 34 | dex_file_(dex_file), |
| 35 | code_item_(code_item), |
| 36 | branch_targets_(code_item.insns_size_in_code_units_, |
| 37 | nullptr, |
| 38 | arena_->Adapter(kArenaAllocGraphBuilder)), |
| 39 | throwing_blocks_(kDefaultNumberOfThrowingBlocks, arena_->Adapter(kArenaAllocGraphBuilder)), |
| 40 | number_of_branches_(0u) {} |
| 41 | |
| 42 | // Creates basic blocks in `graph_` at branch target dex_pc positions of the |
| 43 | // `code_item_`. Blocks are connected but left unpopulated with instructions. |
| 44 | // TryBoundary blocks are inserted at positions where control-flow enters/ |
| 45 | // exits a try block. |
| 46 | bool Build(); |
| 47 | |
| 48 | size_t GetNumberOfBranches() const { return number_of_branches_; } |
| 49 | HBasicBlock* GetBlockAt(uint32_t dex_pc) const { return branch_targets_[dex_pc]; } |
| 50 | |
| 51 | private: |
| 52 | // Creates a basic block starting at given `dex_pc`. |
| 53 | HBasicBlock* MaybeCreateBlockAt(uint32_t dex_pc); |
| 54 | |
| 55 | // Creates a basic block for bytecode instructions at `semantic_dex_pc` and |
| 56 | // stores it under the `store_dex_pc` key. This is used when multiple blocks |
| 57 | // share the same semantic dex_pc, e.g. when building switch decision trees. |
| 58 | HBasicBlock* MaybeCreateBlockAt(uint32_t semantic_dex_pc, uint32_t store_dex_pc); |
| 59 | |
| 60 | bool CreateBranchTargets(); |
| 61 | void ConnectBasicBlocks(); |
| 62 | void InsertTryBoundaryBlocks(); |
| 63 | |
| 64 | // Helper method which decides whether `catch_block` may have live normal |
| 65 | // predecessors and thus whether a synthetic catch block needs to be created |
| 66 | // to avoid mixing normal and exceptional predecessors. |
| 67 | // Should only be called during InsertTryBoundaryBlocks on blocks at catch |
| 68 | // handler dex_pcs. |
| 69 | bool MightHaveLiveNormalPredecessors(HBasicBlock* catch_block); |
| 70 | |
| 71 | ArenaAllocator* const arena_; |
| 72 | HGraph* const graph_; |
| 73 | |
| 74 | const DexFile* const dex_file_; |
| 75 | const DexFile::CodeItem& code_item_; |
| 76 | |
| 77 | ArenaVector<HBasicBlock*> branch_targets_; |
| 78 | ArenaVector<HBasicBlock*> throwing_blocks_; |
| 79 | size_t number_of_branches_; |
| 80 | |
| 81 | static constexpr size_t kDefaultNumberOfThrowingBlocks = 2u; |
| 82 | |
| 83 | DISALLOW_COPY_AND_ASSIGN(HBasicBlockBuilder); |
| 84 | }; |
| 85 | |
| 86 | } // namespace art |
| 87 | |
| 88 | #endif // ART_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_ |