1 // Copyright (c) 2017 The Khronos Group Inc. 2 // Copyright (c) 2017 Valve Corporation 3 // Copyright (c) 2017 LunarG Inc. 4 // 5 // Licensed under the Apache License, Version 2.0 (the "License"); 6 // you may not use this file except in compliance with the License. 7 // You may obtain a copy of the License at 8 // 9 // http://www.apache.org/licenses/LICENSE-2.0 10 // 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 17 #ifndef SOURCE_OPT_MEM_PASS_H_ 18 #define SOURCE_OPT_MEM_PASS_H_ 19 20 #include <algorithm> 21 #include <list> 22 #include <map> 23 #include <queue> 24 #include <unordered_map> 25 #include <unordered_set> 26 #include <utility> 27 28 #include "source/opt/basic_block.h" 29 #include "source/opt/def_use_manager.h" 30 #include "source/opt/dominator_analysis.h" 31 #include "source/opt/module.h" 32 #include "source/opt/pass.h" 33 34 namespace spvtools { 35 namespace opt { 36 37 // A common base class for mem2reg-type passes. Provides common 38 // utility functions and supporting state. 39 class MemPass : public Pass { 40 public: 41 virtual ~MemPass() = default; 42 43 // Returns an undef value for the given |var_id|'s type. GetUndefVal(uint32_t var_id)44 uint32_t GetUndefVal(uint32_t var_id) { 45 return Type2Undef(GetPointeeTypeId(get_def_use_mgr()->GetDef(var_id))); 46 } 47 48 // Given a load or store |ip|, return the pointer instruction. 49 // Also return the base variable's id in |varId|. If no base variable is 50 // found, |varId| will be 0. 51 Instruction* GetPtr(Instruction* ip, uint32_t* varId); 52 53 // Return true if |varId| is a previously identified target variable. 54 // Return false if |varId| is a previously identified non-target variable. 55 // 56 // Non-target variables are variable of function scope of a target type that 57 // are accessed with constant-index access chains. not accessed with 58 // non-constant-index access chains. Also cache non-target variables. 59 // 60 // If variable is not cached, return true if variable is a function scope 61 // variable of target type, false otherwise. Updates caches of target and 62 // non-target variables. 63 bool IsTargetVar(uint32_t varId); 64 65 // Collect target SSA variables. This traverses all the loads and stores in 66 // function |func| looking for variables that can be replaced with SSA IDs. It 67 // populates the sets |seen_target_vars_| and |seen_non_target_vars_|. 68 void CollectTargetVars(Function* func); 69 70 protected: 71 MemPass(); 72 73 // Returns true if |typeInst| is a scalar type 74 // or a vector or matrix 75 bool IsBaseTargetType(const Instruction* typeInst) const; 76 77 // Returns true if |typeInst| is a math type or a struct or array 78 // of a math type. 79 // TODO(): Add more complex types to convert 80 bool IsTargetType(const Instruction* typeInst) const; 81 82 // Returns true if |opcode| is a non-ptr access chain op 83 bool IsNonPtrAccessChain(const SpvOp opcode) const; 84 85 // Given the id |ptrId|, return true if the top-most non-CopyObj is 86 // a variable, a non-ptr access chain or a parameter of pointer type. 87 bool IsPtr(uint32_t ptrId); 88 89 // Given the id of a pointer |ptrId|, return the top-most non-CopyObj. 90 // Also return the base variable's id in |varId|. If no base variable is 91 // found, |varId| will be 0. 92 Instruction* GetPtr(uint32_t ptrId, uint32_t* varId); 93 94 // Return true if all uses of |id| are only name or decorate ops. 95 bool HasOnlyNamesAndDecorates(uint32_t id) const; 96 97 // Kill all instructions in block |bp|. Whether or not to kill the label is 98 // indicated by |killLabel|. 99 void KillAllInsts(BasicBlock* bp, bool killLabel = true); 100 101 // Return true if any instruction loads from |varId| 102 bool HasLoads(uint32_t varId) const; 103 104 // Return true if |varId| is not a function variable or if it has 105 // a load 106 bool IsLiveVar(uint32_t varId) const; 107 108 // Add stores using |ptr_id| to |insts| 109 void AddStores(uint32_t ptr_id, std::queue<Instruction*>* insts); 110 111 // Delete |inst| and iterate DCE on all its operands if they are now 112 // useless. If a load is deleted and its variable has no other loads, 113 // delete all its variable's stores. 114 void DCEInst(Instruction* inst, const std::function<void(Instruction*)>&); 115 116 // Call all the cleanup helper functions on |func|. 117 bool CFGCleanup(Function* func); 118 119 // Return true if |op| is supported decorate. IsNonTypeDecorate(uint32_t op)120 inline bool IsNonTypeDecorate(uint32_t op) const { 121 return (op == SpvOpDecorate || op == SpvOpDecorateId); 122 } 123 124 // Return undef in function for type. Create and insert an undef after the 125 // first non-variable in the function if it doesn't already exist. Add 126 // undef to function undef map. 127 uint32_t Type2Undef(uint32_t type_id); 128 129 // Cache of verified target vars 130 std::unordered_set<uint32_t> seen_target_vars_; 131 132 // Cache of verified non-target vars 133 std::unordered_set<uint32_t> seen_non_target_vars_; 134 135 private: 136 // Return true if all uses of |varId| are only through supported reference 137 // operations ie. loads and store. Also cache in supported_ref_vars_. 138 // TODO(dnovillo): This function is replicated in other passes and it's 139 // slightly different in every pass. Is it possible to make one common 140 // implementation? 141 bool HasOnlySupportedRefs(uint32_t varId); 142 143 // Remove all the unreachable basic blocks in |func|. 144 bool RemoveUnreachableBlocks(Function* func); 145 146 // Remove the block pointed by the iterator |*bi|. This also removes 147 // all the instructions in the pointed-to block. 148 void RemoveBlock(Function::iterator* bi); 149 150 // Remove Phi operands in |phi| that are coming from blocks not in 151 // |reachable_blocks|. 152 void RemovePhiOperands( 153 Instruction* phi, 154 const std::unordered_set<BasicBlock*>& reachable_blocks); 155 156 // Map from type to undef 157 std::unordered_map<uint32_t, uint32_t> type2undefs_; 158 }; 159 160 } // namespace opt 161 } // namespace spvtools 162 163 #endif // SOURCE_OPT_MEM_PASS_H_ 164