1 //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines various functions that are used to clone chunks of LLVM 11 // code for various purposes. This varies from copying whole modules into new 12 // modules, to cloning functions with different arguments, to inlining 13 // functions, to copying basic blocks to support loop unrolling or superblock 14 // formation, etc. 15 // 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H 19 #define LLVM_TRANSFORMS_UTILS_CLONING_H 20 21 #include "llvm/ADT/SmallVector.h" 22 #include "llvm/ADT/Twine.h" 23 #include "llvm/IR/ValueHandle.h" 24 #include "llvm/IR/ValueMap.h" 25 #include "llvm/Transforms/Utils/ValueMapper.h" 26 27 namespace llvm { 28 29 class Module; 30 class Function; 31 class Instruction; 32 class Pass; 33 class LPPassManager; 34 class BasicBlock; 35 class Value; 36 class CallInst; 37 class InvokeInst; 38 class ReturnInst; 39 class CallSite; 40 class Trace; 41 class CallGraph; 42 class DataLayout; 43 class Loop; 44 class LoopInfo; 45 class AllocaInst; 46 47 /// CloneModule - Return an exact copy of the specified module 48 /// 49 Module *CloneModule(const Module *M); 50 Module *CloneModule(const Module *M, ValueToValueMapTy &VMap); 51 52 /// ClonedCodeInfo - This struct can be used to capture information about code 53 /// being cloned, while it is being cloned. 54 struct ClonedCodeInfo { 55 /// ContainsCalls - This is set to true if the cloned code contains a normal 56 /// call instruction. 57 bool ContainsCalls; 58 59 /// ContainsDynamicAllocas - This is set to true if the cloned code contains 60 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in 61 /// the entry block or they are in the entry block but are not a constant 62 /// size. 63 bool ContainsDynamicAllocas; 64 65 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {} 66 }; 67 68 /// CloneBasicBlock - Return a copy of the specified basic block, but without 69 /// embedding the block into a particular function. The block returned is an 70 /// exact copy of the specified basic block, without any remapping having been 71 /// performed. Because of this, this is only suitable for applications where 72 /// the basic block will be inserted into the same function that it was cloned 73 /// from (loop unrolling would use this, for example). 74 /// 75 /// Also, note that this function makes a direct copy of the basic block, and 76 /// can thus produce illegal LLVM code. In particular, it will copy any PHI 77 /// nodes from the original block, even though there are no predecessors for the 78 /// newly cloned block (thus, phi nodes will have to be updated). Also, this 79 /// block will branch to the old successors of the original block: these 80 /// successors will have to have any PHI nodes updated to account for the new 81 /// incoming edges. 82 /// 83 /// The correlation between instructions in the source and result basic blocks 84 /// is recorded in the VMap map. 85 /// 86 /// If you have a particular suffix you'd like to use to add to any cloned 87 /// names, specify it as the optional third parameter. 88 /// 89 /// If you would like the basic block to be auto-inserted into the end of a 90 /// function, you can specify it as the optional fourth parameter. 91 /// 92 /// If you would like to collect additional information about the cloned 93 /// function, you can specify a ClonedCodeInfo object with the optional fifth 94 /// parameter. 95 /// 96 BasicBlock *CloneBasicBlock(const BasicBlock *BB, 97 ValueToValueMapTy &VMap, 98 const Twine &NameSuffix = "", Function *F = nullptr, 99 ClonedCodeInfo *CodeInfo = nullptr); 100 101 /// CloneFunction - Return a copy of the specified function, but without 102 /// embedding the function into another module. Also, any references specified 103 /// in the VMap are changed to refer to their mapped value instead of the 104 /// original one. If any of the arguments to the function are in the VMap, 105 /// the arguments are deleted from the resultant function. The VMap is 106 /// updated to include mappings from all of the instructions and basicblocks in 107 /// the function from their old to new values. The final argument captures 108 /// information about the cloned code if non-null. 109 /// 110 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 111 /// mappings, and debug info metadata will not be cloned. 112 /// 113 Function *CloneFunction(const Function *F, 114 ValueToValueMapTy &VMap, 115 bool ModuleLevelChanges, 116 ClonedCodeInfo *CodeInfo = nullptr); 117 118 /// Clone OldFunc into NewFunc, transforming the old arguments into references 119 /// to VMap values. Note that if NewFunc already has basic blocks, the ones 120 /// cloned into it will be added to the end of the function. This function 121 /// fills in a list of return instructions, and can optionally remap types 122 /// and/or append the specified suffix to all values cloned. 123 /// 124 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 125 /// mappings. 126 /// 127 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 128 ValueToValueMapTy &VMap, 129 bool ModuleLevelChanges, 130 SmallVectorImpl<ReturnInst*> &Returns, 131 const char *NameSuffix = "", 132 ClonedCodeInfo *CodeInfo = nullptr, 133 ValueMapTypeRemapper *TypeMapper = nullptr, 134 ValueMaterializer *Materializer = nullptr); 135 136 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, 137 /// except that it does some simple constant prop and DCE on the fly. The 138 /// effect of this is to copy significantly less code in cases where (for 139 /// example) a function call with constant arguments is inlined, and those 140 /// constant arguments cause a significant amount of code in the callee to be 141 /// dead. Since this doesn't produce an exactly copy of the input, it can't be 142 /// used for things like CloneFunction or CloneModule. 143 /// 144 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 145 /// mappings. 146 /// 147 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, 148 ValueToValueMapTy &VMap, 149 bool ModuleLevelChanges, 150 SmallVectorImpl<ReturnInst*> &Returns, 151 const char *NameSuffix = "", 152 ClonedCodeInfo *CodeInfo = nullptr, 153 const DataLayout *DL = nullptr, 154 Instruction *TheCall = nullptr); 155 156 /// InlineFunctionInfo - This class captures the data input to the 157 /// InlineFunction call, and records the auxiliary results produced by it. 158 class InlineFunctionInfo { 159 public: 160 explicit InlineFunctionInfo(CallGraph *cg = nullptr, const DataLayout *DL = nullptr) 161 : CG(cg), DL(DL) {} 162 163 /// CG - If non-null, InlineFunction will update the callgraph to reflect the 164 /// changes it makes. 165 CallGraph *CG; 166 const DataLayout *DL; 167 168 /// StaticAllocas - InlineFunction fills this in with all static allocas that 169 /// get copied into the caller. 170 SmallVector<AllocaInst*, 4> StaticAllocas; 171 172 /// InlinedCalls - InlineFunction fills this in with callsites that were 173 /// inlined from the callee. This is only filled in if CG is non-null. 174 SmallVector<WeakVH, 8> InlinedCalls; 175 176 void reset() { 177 StaticAllocas.clear(); 178 InlinedCalls.clear(); 179 } 180 }; 181 182 /// InlineFunction - This function inlines the called function into the basic 183 /// block of the caller. This returns false if it is not possible to inline 184 /// this call. The program is still in a well defined state if this occurs 185 /// though. 186 /// 187 /// Note that this only does one level of inlining. For example, if the 188 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 189 /// exists in the instruction stream. Similarly this will inline a recursive 190 /// function by one level. 191 /// 192 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, bool InsertLifetime = true); 193 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime = true); 194 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime = true); 195 196 } // End llvm namespace 197 198 #endif 199
