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 26 namespace llvm { 27 28 class Module; 29 class Function; 30 class Instruction; 31 class Pass; 32 class LPPassManager; 33 class BasicBlock; 34 class Value; 35 class CallInst; 36 class InvokeInst; 37 class ReturnInst; 38 class CallSite; 39 class Trace; 40 class CallGraph; 41 class TargetData; 42 class Loop; 43 class LoopInfo; 44 class AllocaInst; 45 46 /// CloneModule - Return an exact copy of the specified module 47 /// 48 Module *CloneModule(const Module *M); 49 Module *CloneModule(const Module *M, ValueMap<const Value*, Value*> &VMap); 50 51 /// ClonedCodeInfo - This struct can be used to capture information about code 52 /// being cloned, while it is being cloned. 53 struct ClonedCodeInfo { 54 /// ContainsCalls - This is set to true if the cloned code contains a normal 55 /// call instruction. 56 bool ContainsCalls; 57 58 /// ContainsUnwinds - This is set to true if the cloned code contains an 59 /// unwind instruction. 60 bool ContainsUnwinds; 61 62 /// ContainsDynamicAllocas - This is set to true if the cloned code contains 63 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in 64 /// the entry block or they are in the entry block but are not a constant 65 /// size. 66 bool ContainsDynamicAllocas; 67 ClonedCodeInfoClonedCodeInfo68 ClonedCodeInfo() { 69 ContainsCalls = false; 70 ContainsUnwinds = false; 71 ContainsDynamicAllocas = false; 72 } 73 }; 74 75 76 /// CloneBasicBlock - Return a copy of the specified basic block, but without 77 /// embedding the block into a particular function. The block returned is an 78 /// exact copy of the specified basic block, without any remapping having been 79 /// performed. Because of this, this is only suitable for applications where 80 /// the basic block will be inserted into the same function that it was cloned 81 /// from (loop unrolling would use this, for example). 82 /// 83 /// Also, note that this function makes a direct copy of the basic block, and 84 /// can thus produce illegal LLVM code. In particular, it will copy any PHI 85 /// nodes from the original block, even though there are no predecessors for the 86 /// newly cloned block (thus, phi nodes will have to be updated). Also, this 87 /// block will branch to the old successors of the original block: these 88 /// successors will have to have any PHI nodes updated to account for the new 89 /// incoming edges. 90 /// 91 /// The correlation between instructions in the source and result basic blocks 92 /// is recorded in the VMap map. 93 /// 94 /// If you have a particular suffix you'd like to use to add to any cloned 95 /// names, specify it as the optional third parameter. 96 /// 97 /// If you would like the basic block to be auto-inserted into the end of a 98 /// function, you can specify it as the optional fourth parameter. 99 /// 100 /// If you would like to collect additional information about the cloned 101 /// function, you can specify a ClonedCodeInfo object with the optional fifth 102 /// parameter. 103 /// 104 BasicBlock *CloneBasicBlock(const BasicBlock *BB, 105 ValueMap<const Value*, Value*> &VMap, 106 const Twine &NameSuffix = "", Function *F = 0, 107 ClonedCodeInfo *CodeInfo = 0); 108 109 110 /// CloneLoop - Clone Loop. Clone dominator info for loop insiders. Populate 111 /// VMap using old blocks to new blocks mapping. 112 Loop *CloneLoop(Loop *L, LPPassManager *LPM, LoopInfo *LI, 113 ValueMap<const Value *, Value *> &VMap, Pass *P); 114 115 /// CloneFunction - Return a copy of the specified function, but without 116 /// embedding the function into another module. Also, any references specified 117 /// in the VMap are changed to refer to their mapped value instead of the 118 /// original one. If any of the arguments to the function are in the VMap, 119 /// the arguments are deleted from the resultant function. The VMap is 120 /// updated to include mappings from all of the instructions and basicblocks in 121 /// the function from their old to new values. The final argument captures 122 /// information about the cloned code if non-null. 123 /// 124 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 125 /// mappings. 126 /// 127 Function *CloneFunction(const Function *F, 128 ValueMap<const Value*, Value*> &VMap, 129 bool ModuleLevelChanges, 130 ClonedCodeInfo *CodeInfo = 0); 131 132 /// CloneFunction - Version of the function that doesn't need the VMap. 133 /// 134 inline Function *CloneFunction(const Function *F, ClonedCodeInfo *CodeInfo = 0){ 135 ValueMap<const Value*, Value*> VMap; 136 return CloneFunction(F, VMap, CodeInfo); 137 } 138 139 /// Clone OldFunc into NewFunc, transforming the old arguments into references 140 /// to VMap values. Note that if NewFunc already has basic blocks, the ones 141 /// cloned into it will be added to the end of the function. This function 142 /// fills in a list of return instructions, and can optionally append the 143 /// specified suffix to all values cloned. 144 /// 145 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 146 /// mappings. 147 /// 148 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 149 ValueMap<const Value*, Value*> &VMap, 150 bool ModuleLevelChanges, 151 SmallVectorImpl<ReturnInst*> &Returns, 152 const char *NameSuffix = "", 153 ClonedCodeInfo *CodeInfo = 0); 154 155 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, 156 /// except that it does some simple constant prop and DCE on the fly. The 157 /// effect of this is to copy significantly less code in cases where (for 158 /// example) a function call with constant arguments is inlined, and those 159 /// constant arguments cause a significant amount of code in the callee to be 160 /// dead. Since this doesn't produce an exactly copy of the input, it can't be 161 /// used for things like CloneFunction or CloneModule. 162 /// 163 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 164 /// mappings. 165 /// 166 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, 167 ValueMap<const Value*, Value*> &VMap, 168 bool ModuleLevelChanges, 169 SmallVectorImpl<ReturnInst*> &Returns, 170 const char *NameSuffix = "", 171 ClonedCodeInfo *CodeInfo = 0, 172 const TargetData *TD = 0, 173 Instruction *TheCall = 0); 174 175 176 /// InlineFunctionInfo - This class captures the data input to the 177 /// InlineFunction call, and records the auxiliary results produced by it. 178 class InlineFunctionInfo { 179 public: 180 explicit InlineFunctionInfo(CallGraph *cg = 0, const TargetData *td = 0) CG(cg)181 : CG(cg), TD(td) {} 182 183 /// CG - If non-null, InlineFunction will update the callgraph to reflect the 184 /// changes it makes. 185 CallGraph *CG; 186 const TargetData *TD; 187 188 /// StaticAllocas - InlineFunction fills this in with all static allocas that 189 /// get copied into the caller. 190 SmallVector<AllocaInst*, 4> StaticAllocas; 191 192 /// InlinedCalls - InlineFunction fills this in with callsites that were 193 /// inlined from the callee. This is only filled in if CG is non-null. 194 SmallVector<WeakVH, 8> InlinedCalls; 195 reset()196 void reset() { 197 StaticAllocas.clear(); 198 InlinedCalls.clear(); 199 } 200 }; 201 202 /// InlineFunction - This function inlines the called function into the basic 203 /// block of the caller. This returns false if it is not possible to inline 204 /// this call. The program is still in a well defined state if this occurs 205 /// though. 206 /// 207 /// Note that this only does one level of inlining. For example, if the 208 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 209 /// exists in the instruction stream. Similiarly this will inline a recursive 210 /// function by one level. 211 /// 212 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI); 213 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI); 214 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI); 215 216 } // End llvm namespace 217 218 #endif 219