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/Constants.h" 00018 #include "llvm/DerivedTypes.h" 00019 #include "llvm/Instructions.h" 00020 #include "llvm/Function.h" 00021 #include "ValueMapper.h" 00022 using namespace llvm; 00023 00024 // CloneBasicBlock - See comments in Cloning.h 00025 BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, 00026 std::map<const Value*, Value*> &ValueMap, 00027 const char *NameSuffix, Function *F, 00028 ClonedCodeInfo *CodeInfo) { 00029 BasicBlock *NewBB = new BasicBlock("", F); 00030 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix); 00031 00032 bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false; 00033 00034 // Loop over all instructions, and copy them over. 00035 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); 00036 II != IE; ++II) { 00037 Instruction *NewInst = II->clone(); 00038 if (II->hasName()) 00039 NewInst->setName(II->getName()+NameSuffix); 00040 NewBB->getInstList().push_back(NewInst); 00041 ValueMap[II] = NewInst; // Add instruction map to value. 00042 00043 hasCalls |= isa<CallInst>(II); 00044 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) { 00045 if (isa<ConstantInt>(AI->getArraySize())) 00046 hasStaticAllocas = true; 00047 else 00048 hasDynamicAllocas = true; 00049 } 00050 } 00051 00052 if (CodeInfo) { 00053 CodeInfo->ContainsCalls |= hasCalls; 00054 CodeInfo->ContainsUnwinds |= isa<UnwindInst>(BB->getTerminator()); 00055 CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas; 00056 CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas && 00057 BB != &BB->getParent()->front(); 00058 } 00059 return NewBB; 00060 } 00061 00062 // Clone OldFunc into NewFunc, transforming the old arguments into references to 00063 // ArgMap values. 00064 // 00065 void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 00066 std::map<const Value*, Value*> &ValueMap, 00067 std::vector<ReturnInst*> &Returns, 00068 const char *NameSuffix, ClonedCodeInfo *CodeInfo) { 00069 assert(NameSuffix && "NameSuffix cannot be null!"); 00070 00071 #ifndef NDEBUG 00072 for (Function::const_arg_iterator I = OldFunc->arg_begin(), 00073 E = OldFunc->arg_end(); I != E; ++I) 00074 assert(ValueMap.count(I) && "No mapping from source argument specified!"); 00075 #endif 00076 00077 // Loop over all of the basic blocks in the function, cloning them as 00078 // appropriate. Note that we save BE this way in order to handle cloning of 00079 // recursive functions into themselves. 00080 // 00081 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end(); 00082 BI != BE; ++BI) { 00083 const BasicBlock &BB = *BI; 00084 00085 // Create a new basic block and copy instructions into it! 00086 BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix, NewFunc, 00087 CodeInfo); 00088 ValueMap[&BB] = CBB; // Add basic block mapping. 00089 00090 if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator())) 00091 Returns.push_back(RI); 00092 } 00093 00094 // Loop over all of the instructions in the function, fixing up operand 00095 // references as we go. This uses ValueMap to do all the hard work. 00096 // 00097 for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]), 00098 BE = NewFunc->end(); BB != BE; ++BB) 00099 // Loop over all instructions, fixing each one as we find it... 00100 for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II) 00101 RemapInstruction(II, ValueMap); 00102 } 00103 00104 /// CloneFunction - Return a copy of the specified function, but without 00105 /// embedding the function into another module. Also, any references specified 00106 /// in the ValueMap are changed to refer to their mapped value instead of the 00107 /// original one. If any of the arguments to the function are in the ValueMap, 00108 /// the arguments are deleted from the resultant function. The ValueMap is 00109 /// updated to include mappings from all of the instructions and basicblocks in 00110 /// the function from their old to new values. 00111 /// 00112 Function *llvm::CloneFunction(const Function *F, 00113 std::map<const Value*, Value*> &ValueMap, 00114 ClonedCodeInfo *CodeInfo) { 00115 std::vector<const Type*> ArgTypes; 00116 00117 // The user might be deleting arguments to the function by specifying them in 00118 // the ValueMap. If so, we need to not add the arguments to the arg ty vector 00119 // 00120 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end(); 00121 I != E; ++I) 00122 if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet? 00123 ArgTypes.push_back(I->getType()); 00124 00125 // Create a new function type... 00126 FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(), 00127 ArgTypes, F->getFunctionType()->isVarArg()); 00128 00129 // Create the new function... 00130 Function *NewF = new Function(FTy, F->getLinkage(), F->getName()); 00131 00132 // Loop over the arguments, copying the names of the mapped arguments over... 00133 Function::arg_iterator DestI = NewF->arg_begin(); 00134 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end(); 00135 I != E; ++I) 00136 if (ValueMap.count(I) == 0) { // Is this argument preserved? 00137 DestI->setName(I->getName()); // Copy the name over... 00138 ValueMap[I] = DestI++; // Add mapping to ValueMap 00139 } 00140 00141 std::vector<ReturnInst*> Returns; // Ignore returns cloned... 00142 CloneFunctionInto(NewF, F, ValueMap, Returns, "", CodeInfo); 00143 return NewF; 00144 } 00145