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/ValueMap.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/ADT/Twine.h" 24 #include "llvm/Support/ValueHandle.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 TargetData; 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 /// ContainsUnwinds - This is set to true if the cloned code contains an 60 /// unwind instruction. 61 bool ContainsUnwinds; 62 63 /// ContainsDynamicAllocas - This is set to true if the cloned code contains 64 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in 65 /// the entry block or they are in the entry block but are not a constant 66 /// size. 67 bool ContainsDynamicAllocas; 68 69 ClonedCodeInfo() { 70 ContainsCalls = false; 71 ContainsUnwinds = false; 72 ContainsDynamicAllocas = false; 73 } 74 }; 75 76 77 /// CloneBasicBlock - Return a copy of the specified basic block, but without 78 /// embedding the block into a particular function. The block returned is an 79 /// exact copy of the specified basic block, without any remapping having been 80 /// performed. Because of this, this is only suitable for applications where 81 /// the basic block will be inserted into the same function that it was cloned 82 /// from (loop unrolling would use this, for example). 83 /// 84 /// Also, note that this function makes a direct copy of the basic block, and 85 /// can thus produce illegal LLVM code. In particular, it will copy any PHI 86 /// nodes from the original block, even though there are no predecessors for the 87 /// newly cloned block (thus, phi nodes will have to be updated). Also, this 88 /// block will branch to the old successors of the original block: these 89 /// successors will have to have any PHI nodes updated to account for the new 90 /// incoming edges. 91 /// 92 /// The correlation between instructions in the source and result basic blocks 93 /// is recorded in the VMap map. 94 /// 95 /// If you have a particular suffix you'd like to use to add to any cloned 96 /// names, specify it as the optional third parameter. 97 /// 98 /// If you would like the basic block to be auto-inserted into the end of a 99 /// function, you can specify it as the optional fourth parameter. 100 /// 101 /// If you would like to collect additional information about the cloned 102 /// function, you can specify a ClonedCodeInfo object with the optional fifth 103 /// parameter. 104 /// 105 BasicBlock *CloneBasicBlock(const BasicBlock *BB, 106 ValueToValueMapTy &VMap, 107 const Twine &NameSuffix = "", Function *F = 0, 108 ClonedCodeInfo *CodeInfo = 0); 109 110 /// CloneFunction - Return a copy of the specified function, but without 111 /// embedding the function into another module. Also, any references specified 112 /// in the VMap are changed to refer to their mapped value instead of the 113 /// original one. If any of the arguments to the function are in the VMap, 114 /// the arguments are deleted from the resultant function. The VMap is 115 /// updated to include mappings from all of the instructions and basicblocks in 116 /// the function from their old to new values. The final argument captures 117 /// information about the cloned code if non-null. 118 /// 119 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 120 /// mappings. 121 /// 122 Function *CloneFunction(const Function *F, 123 ValueToValueMapTy &VMap, 124 bool ModuleLevelChanges, 125 ClonedCodeInfo *CodeInfo = 0); 126 127 /// CloneFunction - Version of the function that doesn't need the VMap. 128 /// 129 inline Function *CloneFunction(const Function *F, ClonedCodeInfo *CodeInfo = 0){ 130 ValueToValueMapTy VMap; 131 return CloneFunction(F, VMap, CodeInfo); 132 } 133 134 /// Clone OldFunc into NewFunc, transforming the old arguments into references 135 /// to VMap values. Note that if NewFunc already has basic blocks, the ones 136 /// cloned into it will be added to the end of the function. This function 137 /// fills in a list of return instructions, and can optionally append the 138 /// specified suffix to all values cloned. 139 /// 140 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 141 /// mappings. 142 /// 143 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 144 ValueToValueMapTy &VMap, 145 bool ModuleLevelChanges, 146 SmallVectorImpl<ReturnInst*> &Returns, 147 const char *NameSuffix = "", 148 ClonedCodeInfo *CodeInfo = 0); 149 150 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, 151 /// except that it does some simple constant prop and DCE on the fly. The 152 /// effect of this is to copy significantly less code in cases where (for 153 /// example) a function call with constant arguments is inlined, and those 154 /// constant arguments cause a significant amount of code in the callee to be 155 /// dead. Since this doesn't produce an exactly copy of the input, it can't be 156 /// used for things like CloneFunction or CloneModule. 157 /// 158 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 159 /// mappings. 160 /// 161 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, 162 ValueToValueMapTy &VMap, 163 bool ModuleLevelChanges, 164 SmallVectorImpl<ReturnInst*> &Returns, 165 const char *NameSuffix = "", 166 ClonedCodeInfo *CodeInfo = 0, 167 const TargetData *TD = 0, 168 Instruction *TheCall = 0); 169 170 171 /// InlineFunctionInfo - This class captures the data input to the 172 /// InlineFunction call, and records the auxiliary results produced by it. 173 class InlineFunctionInfo { 174 public: 175 explicit InlineFunctionInfo(CallGraph *cg = 0, const TargetData *td = 0) 176 : CG(cg), TD(td) {} 177 178 /// CG - If non-null, InlineFunction will update the callgraph to reflect the 179 /// changes it makes. 180 CallGraph *CG; 181 const TargetData *TD; 182 183 /// StaticAllocas - InlineFunction fills this in with all static allocas that 184 /// get copied into the caller. 185 SmallVector<AllocaInst*, 4> StaticAllocas; 186 187 /// InlinedCalls - InlineFunction fills this in with callsites that were 188 /// inlined from the callee. This is only filled in if CG is non-null. 189 SmallVector<WeakVH, 8> InlinedCalls; 190 191 void reset() { 192 StaticAllocas.clear(); 193 InlinedCalls.clear(); 194 } 195 }; 196 197 /// InlineFunction - This function inlines the called function into the basic 198 /// block of the caller. This returns false if it is not possible to inline 199 /// this call. The program is still in a well defined state if this occurs 200 /// though. 201 /// 202 /// Note that this only does one level of inlining. For example, if the 203 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 204 /// exists in the instruction stream. Similarly this will inline a recursive 205 /// function by one level. 206 /// 207 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI); 208 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI); 209 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI); 210 211 } // End llvm namespace 212 213 #endif 214
