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 class AliasAnalysis; 47 class AssumptionCacheTracker; 48 49 /// CloneModule - Return an exact copy of the specified module 50 /// 51 Module *CloneModule(const Module *M); 52 Module *CloneModule(const Module *M, ValueToValueMapTy &VMap); 53 54 /// ClonedCodeInfo - This struct can be used to capture information about code 55 /// being cloned, while it is being cloned. 56 struct ClonedCodeInfo { 57 /// ContainsCalls - This is set to true if the cloned code contains a normal 58 /// call instruction. 59 bool ContainsCalls; 60 61 /// ContainsDynamicAllocas - This is set to true if the cloned code contains 62 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in 63 /// the entry block or they are in the entry block but are not a constant 64 /// size. 65 bool ContainsDynamicAllocas; 66 ClonedCodeInfoClonedCodeInfo67 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {} 68 }; 69 70 /// CloneBasicBlock - Return a copy of the specified basic block, but without 71 /// embedding the block into a particular function. The block returned is an 72 /// exact copy of the specified basic block, without any remapping having been 73 /// performed. Because of this, this is only suitable for applications where 74 /// the basic block will be inserted into the same function that it was cloned 75 /// from (loop unrolling would use this, for example). 76 /// 77 /// Also, note that this function makes a direct copy of the basic block, and 78 /// can thus produce illegal LLVM code. In particular, it will copy any PHI 79 /// nodes from the original block, even though there are no predecessors for the 80 /// newly cloned block (thus, phi nodes will have to be updated). Also, this 81 /// block will branch to the old successors of the original block: these 82 /// successors will have to have any PHI nodes updated to account for the new 83 /// incoming edges. 84 /// 85 /// The correlation between instructions in the source and result basic blocks 86 /// is recorded in the VMap map. 87 /// 88 /// If you have a particular suffix you'd like to use to add to any cloned 89 /// names, specify it as the optional third parameter. 90 /// 91 /// If you would like the basic block to be auto-inserted into the end of a 92 /// function, you can specify it as the optional fourth parameter. 93 /// 94 /// If you would like to collect additional information about the cloned 95 /// function, you can specify a ClonedCodeInfo object with the optional fifth 96 /// parameter. 97 /// 98 BasicBlock *CloneBasicBlock(const BasicBlock *BB, 99 ValueToValueMapTy &VMap, 100 const Twine &NameSuffix = "", Function *F = nullptr, 101 ClonedCodeInfo *CodeInfo = nullptr); 102 103 /// CloneFunction - Return a copy of the specified function, but without 104 /// embedding the function into another module. Also, any references specified 105 /// in the VMap are changed to refer to their mapped value instead of the 106 /// original one. If any of the arguments to the function are in the VMap, 107 /// the arguments are deleted from the resultant function. The VMap is 108 /// updated to include mappings from all of the instructions and basicblocks in 109 /// the function from their old to new values. The final argument captures 110 /// information about the cloned code if non-null. 111 /// 112 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 113 /// mappings, and debug info metadata will not be cloned. 114 /// 115 Function *CloneFunction(const Function *F, 116 ValueToValueMapTy &VMap, 117 bool ModuleLevelChanges, 118 ClonedCodeInfo *CodeInfo = nullptr); 119 120 /// Clone OldFunc into NewFunc, transforming the old arguments into references 121 /// to VMap values. Note that if NewFunc already has basic blocks, the ones 122 /// cloned into it will be added to the end of the function. This function 123 /// fills in a list of return instructions, and can optionally remap types 124 /// and/or append the specified suffix to all values cloned. 125 /// 126 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 127 /// mappings. 128 /// 129 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 130 ValueToValueMapTy &VMap, 131 bool ModuleLevelChanges, 132 SmallVectorImpl<ReturnInst*> &Returns, 133 const char *NameSuffix = "", 134 ClonedCodeInfo *CodeInfo = nullptr, 135 ValueMapTypeRemapper *TypeMapper = nullptr, 136 ValueMaterializer *Materializer = nullptr); 137 138 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, 139 /// except that it does some simple constant prop and DCE on the fly. The 140 /// effect of this is to copy significantly less code in cases where (for 141 /// example) a function call with constant arguments is inlined, and those 142 /// constant arguments cause a significant amount of code in the callee to be 143 /// dead. Since this doesn't produce an exactly copy of the input, it can't be 144 /// used for things like CloneFunction or CloneModule. 145 /// 146 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 147 /// mappings. 148 /// 149 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, 150 ValueToValueMapTy &VMap, 151 bool ModuleLevelChanges, 152 SmallVectorImpl<ReturnInst*> &Returns, 153 const char *NameSuffix = "", 154 ClonedCodeInfo *CodeInfo = nullptr, 155 const DataLayout *DL = nullptr, 156 Instruction *TheCall = nullptr); 157 158 /// InlineFunctionInfo - This class captures the data input to the 159 /// InlineFunction call, and records the auxiliary results produced by it. 160 class InlineFunctionInfo { 161 public: 162 explicit InlineFunctionInfo(CallGraph *cg = nullptr, 163 const DataLayout *DL = nullptr, 164 AliasAnalysis *AA = nullptr, 165 AssumptionCacheTracker *ACT = nullptr) CG(cg)166 : CG(cg), DL(DL), AA(AA), ACT(ACT) {} 167 168 /// CG - If non-null, InlineFunction will update the callgraph to reflect the 169 /// changes it makes. 170 CallGraph *CG; 171 const DataLayout *DL; 172 AliasAnalysis *AA; 173 AssumptionCacheTracker *ACT; 174 175 /// StaticAllocas - InlineFunction fills this in with all static allocas that 176 /// get copied into the caller. 177 SmallVector<AllocaInst*, 4> StaticAllocas; 178 179 /// InlinedCalls - InlineFunction fills this in with callsites that were 180 /// inlined from the callee. This is only filled in if CG is non-null. 181 SmallVector<WeakVH, 8> InlinedCalls; 182 reset()183 void reset() { 184 StaticAllocas.clear(); 185 InlinedCalls.clear(); 186 } 187 }; 188 189 /// InlineFunction - This function inlines the called function into the basic 190 /// block of the caller. This returns false if it is not possible to inline 191 /// this call. The program is still in a well defined state if this occurs 192 /// though. 193 /// 194 /// Note that this only does one level of inlining. For example, if the 195 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 196 /// exists in the instruction stream. Similarly this will inline a recursive 197 /// function by one level. 198 /// 199 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, bool InsertLifetime = true); 200 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime = true); 201 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime = true); 202 203 } // End llvm namespace 204 205 #endif 206