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/Analysis/AliasAnalysis.h" 24 #include "llvm/IR/ValueHandle.h" 25 #include "llvm/IR/ValueMap.h" 26 #include "llvm/Transforms/Utils/ValueMapper.h" 27 #include <functional> 28 29 namespace llvm { 30 31 class Module; 32 class Function; 33 class Instruction; 34 class Pass; 35 class LPPassManager; 36 class BasicBlock; 37 class Value; 38 class CallInst; 39 class InvokeInst; 40 class ReturnInst; 41 class CallSite; 42 class Trace; 43 class CallGraph; 44 class DataLayout; 45 class Loop; 46 class LoopInfo; 47 class AllocaInst; 48 class AssumptionCacheTracker; 49 class DominatorTree; 50 51 /// Return an exact copy of the specified module 52 /// 53 std::unique_ptr<Module> CloneModule(const Module *M); 54 std::unique_ptr<Module> CloneModule(const Module *M, ValueToValueMapTy &VMap); 55 56 /// Return a copy of the specified module. The ShouldCloneDefinition function 57 /// controls whether a specific GlobalValue's definition is cloned. If the 58 /// function returns false, the module copy will contain an external reference 59 /// in place of the global definition. 60 std::unique_ptr<Module> 61 CloneModule(const Module *M, ValueToValueMapTy &VMap, 62 function_ref<bool(const GlobalValue *)> ShouldCloneDefinition); 63 64 /// ClonedCodeInfo - This struct can be used to capture information about code 65 /// being cloned, while it is being cloned. 66 struct ClonedCodeInfo { 67 /// ContainsCalls - This is set to true if the cloned code contains a normal 68 /// call instruction. 69 bool ContainsCalls; 70 71 /// ContainsDynamicAllocas - This is set to true if the cloned code contains 72 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in 73 /// the entry block or they are in the entry block but are not a constant 74 /// size. 75 bool ContainsDynamicAllocas; 76 77 /// All cloned call sites that have operand bundles attached are appended to 78 /// this vector. This vector may contain nulls or undefs if some of the 79 /// originally inserted callsites were DCE'ed after they were cloned. 80 std::vector<WeakVH> OperandBundleCallSites; 81 82 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {} 83 }; 84 85 /// CloneBasicBlock - Return a copy of the specified basic block, but without 86 /// embedding the block into a particular function. The block returned is an 87 /// exact copy of the specified basic block, without any remapping having been 88 /// performed. Because of this, this is only suitable for applications where 89 /// the basic block will be inserted into the same function that it was cloned 90 /// from (loop unrolling would use this, for example). 91 /// 92 /// Also, note that this function makes a direct copy of the basic block, and 93 /// can thus produce illegal LLVM code. In particular, it will copy any PHI 94 /// nodes from the original block, even though there are no predecessors for the 95 /// newly cloned block (thus, phi nodes will have to be updated). Also, this 96 /// block will branch to the old successors of the original block: these 97 /// successors will have to have any PHI nodes updated to account for the new 98 /// incoming edges. 99 /// 100 /// The correlation between instructions in the source and result basic blocks 101 /// is recorded in the VMap map. 102 /// 103 /// If you have a particular suffix you'd like to use to add to any cloned 104 /// names, specify it as the optional third parameter. 105 /// 106 /// If you would like the basic block to be auto-inserted into the end of a 107 /// function, you can specify it as the optional fourth parameter. 108 /// 109 /// If you would like to collect additional information about the cloned 110 /// function, you can specify a ClonedCodeInfo object with the optional fifth 111 /// parameter. 112 /// 113 BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap, 114 const Twine &NameSuffix = "", Function *F = nullptr, 115 ClonedCodeInfo *CodeInfo = nullptr); 116 117 /// CloneFunction - Return a copy of the specified function and add it to that 118 /// function's module. Also, any references specified in the VMap are changed 119 /// to refer to their mapped value instead of the original one. If any of the 120 /// arguments to the function are in the VMap, the arguments are deleted from 121 /// the resultant function. The VMap is updated to include mappings from all of 122 /// the instructions and basicblocks in the function from their old to new 123 /// values. The final argument captures information about the cloned code if 124 /// non-null. 125 /// 126 /// VMap contains no non-identity GlobalValue mappings and debug info metadata 127 /// will not be cloned. 128 /// 129 Function *CloneFunction(Function *F, ValueToValueMapTy &VMap, 130 ClonedCodeInfo *CodeInfo = nullptr); 131 132 /// Clone OldFunc into NewFunc, transforming the old arguments into references 133 /// to VMap values. Note that if NewFunc already has basic blocks, the ones 134 /// cloned into it will be added to the end of the function. This function 135 /// fills in a list of return instructions, and can optionally remap types 136 /// and/or append the specified suffix to all values cloned. 137 /// 138 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 139 /// mappings. 140 /// 141 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 142 ValueToValueMapTy &VMap, bool ModuleLevelChanges, 143 SmallVectorImpl<ReturnInst*> &Returns, 144 const char *NameSuffix = "", 145 ClonedCodeInfo *CodeInfo = nullptr, 146 ValueMapTypeRemapper *TypeMapper = nullptr, 147 ValueMaterializer *Materializer = nullptr); 148 149 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, 150 const Instruction *StartingInst, 151 ValueToValueMapTy &VMap, bool ModuleLevelChanges, 152 SmallVectorImpl<ReturnInst *> &Returns, 153 const char *NameSuffix = "", 154 ClonedCodeInfo *CodeInfo = nullptr); 155 156 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, 157 /// except that it does some simple constant prop and DCE on the fly. The 158 /// effect of this is to copy significantly less code in cases where (for 159 /// example) a function call with constant arguments is inlined, and those 160 /// constant arguments cause a significant amount of code in the callee to be 161 /// dead. Since this doesn't produce an exactly copy of the input, it can't be 162 /// used for things like CloneFunction or CloneModule. 163 /// 164 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue 165 /// mappings. 166 /// 167 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, 168 ValueToValueMapTy &VMap, bool ModuleLevelChanges, 169 SmallVectorImpl<ReturnInst*> &Returns, 170 const char *NameSuffix = "", 171 ClonedCodeInfo *CodeInfo = nullptr, 172 Instruction *TheCall = nullptr); 173 174 /// InlineFunctionInfo - This class captures the data input to the 175 /// InlineFunction call, and records the auxiliary results produced by it. 176 class InlineFunctionInfo { 177 public: 178 explicit InlineFunctionInfo(CallGraph *cg = nullptr, 179 AssumptionCacheTracker *ACT = nullptr) 180 : CG(cg), ACT(ACT) {} 181 182 /// CG - If non-null, InlineFunction will update the callgraph to reflect the 183 /// changes it makes. 184 CallGraph *CG; 185 AssumptionCacheTracker *ACT; 186 187 /// StaticAllocas - InlineFunction fills this in with all static allocas that 188 /// get copied into the caller. 189 SmallVector<AllocaInst *, 4> StaticAllocas; 190 191 /// InlinedCalls - InlineFunction fills this in with callsites that were 192 /// inlined from the callee. This is only filled in if CG is non-null. 193 SmallVector<WeakVH, 8> InlinedCalls; 194 195 void reset() { 196 StaticAllocas.clear(); 197 InlinedCalls.clear(); 198 } 199 }; 200 201 /// InlineFunction - This function inlines the called function into the basic 202 /// block of the caller. This returns false if it is not possible to inline 203 /// this call. The program is still in a well defined state if this occurs 204 /// though. 205 /// 206 /// Note that this only does one level of inlining. For example, if the 207 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 208 /// exists in the instruction stream. Similarly this will inline a recursive 209 /// function by one level. 210 /// 211 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, 212 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true); 213 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, 214 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true); 215 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, 216 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true); 217 218 /// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p 219 /// Blocks. 220 /// 221 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block 222 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before. 223 /// Note: Only innermost loops are supported. 224 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB, 225 Loop *OrigLoop, ValueToValueMapTy &VMap, 226 const Twine &NameSuffix, LoopInfo *LI, 227 DominatorTree *DT, 228 SmallVectorImpl<BasicBlock *> &Blocks); 229 230 /// \brief Remaps instructions in \p Blocks using the mapping in \p VMap. 231 void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks, 232 ValueToValueMapTy &VMap); 233 234 } // End llvm namespace 235 236 #endif 237
