LLVM API Documentation
00001 //===- CloneFunction.cpp - Clone a function into another function ---------===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This file implements the CloneFunctionInto interface, which is used as the 00011 // low-level function cloner. This is used by the CloneFunction and function 00012 // inliner to do the dirty work of copying the body of a function around. 00013 // 00014 //===----------------------------------------------------------------------===// 00015 00016 #include "llvm/Transforms/Utils/Cloning.h" 00017 #include "llvm/Instructions.h" 00018 #include "llvm/DerivedTypes.h" 00019 #include "llvm/Function.h" 00020 #include "ValueMapper.h" 00021 using namespace llvm; 00022 00023 // CloneBasicBlock - See comments in Cloning.h 00024 BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, 00025 std::map<const Value*, Value*> &ValueMap, 00026 const char *NameSuffix, Function *F) { 00027 BasicBlock *NewBB = new BasicBlock("", F); 00028 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix); 00029 00030 // Loop over all instructions copying them over... 00031 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); 00032 II != IE; ++II) { 00033 Instruction *NewInst = II->clone(); 00034 if (II->hasName()) 00035 NewInst->setName(II->getName()+NameSuffix); 00036 NewBB->getInstList().push_back(NewInst); 00037 ValueMap[II] = NewInst; // Add instruction map to value. 00038 } 00039 return NewBB; 00040 } 00041 00042 // Clone OldFunc into NewFunc, transforming the old arguments into references to 00043 // ArgMap values. 00044 // 00045 void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 00046 std::map<const Value*, Value*> &ValueMap, 00047 std::vector<ReturnInst*> &Returns, 00048 const char *NameSuffix) { 00049 assert(NameSuffix && "NameSuffix cannot be null!"); 00050 00051 #ifndef NDEBUG 00052 for (Function::const_aiterator I = OldFunc->abegin(), E = OldFunc->aend(); 00053 I != E; ++I) 00054 assert(ValueMap.count(I) && "No mapping from source argument specified!"); 00055 #endif 00056 00057 // Loop over all of the basic blocks in the function, cloning them as 00058 // appropriate. Note that we save BE this way in order to handle cloning of 00059 // recursive functions into themselves. 00060 // 00061 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end(); 00062 BI != BE; ++BI) { 00063 const BasicBlock &BB = *BI; 00064 00065 // Create a new basic block and copy instructions into it! 00066 BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix, NewFunc); 00067 ValueMap[&BB] = CBB; // Add basic block mapping. 00068 00069 if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator())) 00070 Returns.push_back(RI); 00071 } 00072 00073 // Loop over all of the instructions in the function, fixing up operand 00074 // references as we go. This uses ValueMap to do all the hard work. 00075 // 00076 for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]), 00077 BE = NewFunc->end(); BB != BE; ++BB) 00078 // Loop over all instructions, fixing each one as we find it... 00079 for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II) 00080 RemapInstruction(II, ValueMap); 00081 } 00082 00083 /// CloneFunction - Return a copy of the specified function, but without 00084 /// embedding the function into another module. Also, any references specified 00085 /// in the ValueMap are changed to refer to their mapped value instead of the 00086 /// original one. If any of the arguments to the function are in the ValueMap, 00087 /// the arguments are deleted from the resultant function. The ValueMap is 00088 /// updated to include mappings from all of the instructions and basicblocks in 00089 /// the function from their old to new values. 00090 /// 00091 Function *llvm::CloneFunction(const Function *F, 00092 std::map<const Value*, Value*> &ValueMap) { 00093 std::vector<const Type*> ArgTypes; 00094 00095 // The user might be deleting arguments to the function by specifying them in 00096 // the ValueMap. If so, we need to not add the arguments to the arg ty vector 00097 // 00098 for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 00099 if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet? 00100 ArgTypes.push_back(I->getType()); 00101 00102 // Create a new function type... 00103 FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(), 00104 ArgTypes, F->getFunctionType()->isVarArg()); 00105 00106 // Create the new function... 00107 Function *NewF = new Function(FTy, F->getLinkage(), F->getName()); 00108 00109 // Loop over the arguments, copying the names of the mapped arguments over... 00110 Function::aiterator DestI = NewF->abegin(); 00111 for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 00112 if (ValueMap.count(I) == 0) { // Is this argument preserved? 00113 DestI->setName(I->getName()); // Copy the name over... 00114 ValueMap[I] = DestI++; // Add mapping to ValueMap 00115 } 00116 00117 std::vector<ReturnInst*> Returns; // Ignore returns cloned... 00118 CloneFunctionInto(NewF, F, ValueMap, Returns); 00119 return NewF; 00120 } 00121