1 // Copyright (c) 2018 Google LLC. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef SOURCE_OPT_STRUCT_CFG_ANALYSIS_H_ 16 #define SOURCE_OPT_STRUCT_CFG_ANALYSIS_H_ 17 18 #include <unordered_map> 19 20 #include "source/opt/function.h" 21 #include "source/util/bit_vector.h" 22 23 namespace spvtools { 24 namespace opt { 25 26 class IRContext; 27 28 // An analysis that, for each basic block, finds the constructs in which it is 29 // contained, so we can easily get headers and merge nodes. 30 class StructuredCFGAnalysis { 31 public: 32 explicit StructuredCFGAnalysis(IRContext* ctx); 33 34 // Returns the id of the header of the innermost merge construct 35 // that contains |bb_id|. Returns |0| if |bb_id| is not contained in any 36 // merge construct. 37 uint32_t ContainingConstruct(uint32_t bb_id) { 38 auto it = bb_to_construct_.find(bb_id); 39 if (it == bb_to_construct_.end()) { 40 return 0; 41 } 42 return it->second.containing_construct; 43 } 44 45 // Returns the id of the merge block of the innermost merge construct 46 // that contains |bb_id|. Returns |0| if |bb_id| is not contained in any 47 // merge construct. 48 uint32_t MergeBlock(uint32_t bb_id); 49 50 // Returns the id of the header of the innermost loop construct 51 // that contains |bb_id|. Return |0| if |bb_id| is not contained in any loop 52 // construct. 53 uint32_t ContainingLoop(uint32_t bb_id) { 54 auto it = bb_to_construct_.find(bb_id); 55 if (it == bb_to_construct_.end()) { 56 return 0; 57 } 58 return it->second.containing_loop; 59 } 60 61 // Returns the id of the merge block of the innermost loop construct 62 // that contains |bb_id|. Return |0| if |bb_id| is not contained in any loop 63 // construct. 64 uint32_t LoopMergeBlock(uint32_t bb_id); 65 66 // Returns the id of the continue block of the innermost loop construct 67 // that contains |bb_id|. Return |0| if |bb_id| is not contained in any loop 68 // construct. 69 uint32_t LoopContinueBlock(uint32_t bb_id); 70 71 bool IsContinueBlock(uint32_t bb_id); 72 bool IsMergeBlock(uint32_t bb_id); 73 74 private: 75 // Struct used to hold the information for a basic block. 76 // |containing_construct| is the header for the innermost containing 77 // construct, or 0 if no such construct exists. It could be a selection 78 // construct or a loop construct. |containing_loop| is the innermost 79 // containing loop construct, or 0 if the basic bloc is not in a loop. If the 80 // basic block is in a selection construct that is contained in a loop 81 // construct, then these two values will not be the same. 82 struct ConstructInfo { 83 uint32_t containing_construct; 84 uint32_t containing_loop; 85 }; 86 87 // Populates |bb_to_construct_| with the innermost containing merge and loop 88 // constructs for each basic block in |func|. 89 void AddBlocksInFunction(Function* func); 90 91 IRContext* context_; 92 93 // A map from a basic block to the headers of its inner most containing 94 // constructs. 95 std::unordered_map<uint32_t, ConstructInfo> bb_to_construct_; 96 utils::BitVector merge_blocks_; 97 }; 98 99 } // namespace opt 100 } // namespace spvtools 101 #endif // SOURCE_OPT_STRUCT_CFG_ANALYSIS_H_ 102
