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/macros.h" 21 #include "base/scoped_arena_allocator.h" 22 #include "base/scoped_arena_containers.h" 23 #include "dex/code_item_accessors.h" 24 #include "dex/dex_file.h" 25 #include "nodes.h" 26 27 namespace art HIDDEN { 28 29 class HBasicBlockBuilder : public ValueObject { 30 public: 31 HBasicBlockBuilder(HGraph* graph, 32 const DexFile* const dex_file, 33 const CodeItemDebugInfoAccessor& accessor, 34 ScopedArenaAllocator* local_allocator); 35 36 // Creates basic blocks in `graph_` at branch target dex_pc positions of the 37 // `code_item_`. Blocks are connected but left unpopulated with instructions. 38 // TryBoundary blocks are inserted at positions where control-flow enters/ 39 // exits a try block. 40 bool Build(); 41 42 // Creates basic blocks in `graph_` for compiling an intrinsic. 43 void BuildIntrinsic(); 44 GetNumberOfBranches()45 size_t GetNumberOfBranches() const { return number_of_branches_; } GetBlockAt(uint32_t dex_pc)46 HBasicBlock* GetBlockAt(uint32_t dex_pc) const { return branch_targets_[dex_pc]; } 47 48 size_t GetQuickenIndex(uint32_t dex_pc) const; 49 50 private: 51 // Creates a basic block starting at given `dex_pc`. 52 HBasicBlock* MaybeCreateBlockAt(uint32_t dex_pc); 53 54 // Creates a basic block for bytecode instructions at `semantic_dex_pc` and 55 // stores it under the `store_dex_pc` key. This is used when multiple blocks 56 // share the same semantic dex_pc, e.g. when building switch decision trees. 57 HBasicBlock* MaybeCreateBlockAt(uint32_t semantic_dex_pc, uint32_t store_dex_pc); 58 59 bool CreateBranchTargets(); 60 void ConnectBasicBlocks(); 61 void InsertTryBoundaryBlocks(); 62 63 // To ensure branches with negative offsets can always OSR jump to compiled 64 // code, we insert synthesized loops before each block that is the target of a 65 // negative branch. 66 void InsertSynthesizedLoopsForOsr(); 67 68 // Helper method which decides whether `catch_block` may have live normal 69 // predecessors and thus whether a synthetic catch block needs to be created 70 // to avoid mixing normal and exceptional predecessors. 71 // Should only be called during InsertTryBoundaryBlocks on blocks at catch 72 // handler dex_pcs. 73 bool MightHaveLiveNormalPredecessors(HBasicBlock* catch_block); 74 75 ArenaAllocator* const allocator_; 76 HGraph* const graph_; 77 78 const DexFile* const dex_file_; 79 CodeItemDataAccessor code_item_accessor_; // null code item for intrinsic graph. 80 81 ScopedArenaAllocator* const local_allocator_; 82 ScopedArenaVector<HBasicBlock*> branch_targets_; 83 ScopedArenaVector<HBasicBlock*> throwing_blocks_; 84 size_t number_of_branches_; 85 86 // A table to quickly find the quicken index for the first instruction of a basic block. 87 ScopedArenaSafeMap<uint32_t, uint32_t> quicken_index_for_dex_pc_; 88 89 static constexpr size_t kDefaultNumberOfThrowingBlocks = 2u; 90 91 DISALLOW_COPY_AND_ASSIGN(HBasicBlockBuilder); 92 }; 93 94 } // namespace art 95 96 #endif // ART_COMPILER_OPTIMIZING_BLOCK_BUILDER_H_ 97