CloneFunction.cpp revision b576c94c15af9a440f69d9d03c2afead7971118c
1//===- CloneFunction.cpp - Clone a function into another function ---------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the CloneFunctionInto interface, which is used as the 11// low-level function cloner. This is used by the CloneFunction and function 12// inliner to do the dirty work of copying the body of a function around. 13// 14//===----------------------------------------------------------------------===// 15 16#include "llvm/Transforms/Utils/Cloning.h" 17#include "llvm/iTerminators.h" 18#include "llvm/DerivedTypes.h" 19#include "llvm/Function.h" 20#include "ValueMapper.h" 21 22// RemapInstruction - Convert the instruction operands from referencing the 23// current values into those specified by ValueMap. 24// 25static inline void RemapInstruction(Instruction *I, 26 std::map<const Value *, Value*> &ValueMap) { 27 for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) { 28 const Value *Op = I->getOperand(op); 29 Value *V = MapValue(Op, ValueMap); 30#ifndef NDEBUG 31 if (!V) { 32 std::cerr << "Val = \n" << Op << "Addr = " << (void*)Op; 33 std::cerr << "\nInst = " << I; 34 } 35#endif 36 assert(V && "Referenced value not in value map!"); 37 I->setOperand(op, V); 38 } 39} 40 41// CloneBasicBlock - See comments in Cloning.h 42BasicBlock *CloneBasicBlock(const BasicBlock *BB, 43 std::map<const Value*, Value*> &ValueMap, 44 const char *NameSuffix) { 45 BasicBlock *NewBB = new BasicBlock(""); 46 if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix); 47 48 // Loop over all instructions copying them over... 49 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); 50 II != IE; ++II) { 51 Instruction *NewInst = II->clone(); 52 if (II->hasName()) 53 NewInst->setName(II->getName()+NameSuffix); 54 NewBB->getInstList().push_back(NewInst); 55 ValueMap[II] = NewInst; // Add instruction map to value. 56 } 57 return NewBB; 58} 59 60// Clone OldFunc into NewFunc, transforming the old arguments into references to 61// ArgMap values. 62// 63void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, 64 std::map<const Value*, Value*> &ValueMap, 65 std::vector<ReturnInst*> &Returns, 66 const char *NameSuffix) { 67 assert(NameSuffix && "NameSuffix cannot be null!"); 68 69#ifndef NDEBUG 70 for (Function::const_aiterator I = OldFunc->abegin(), E = OldFunc->aend(); 71 I != E; ++I) 72 assert(ValueMap.count(I) && "No mapping from source argument specified!"); 73#endif 74 75 // Loop over all of the basic blocks in the function, cloning them as 76 // appropriate. Note that we save BE this way in order to handle cloning of 77 // recursive functions into themselves. 78 // 79 for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end(); 80 BI != BE; ++BI) { 81 const BasicBlock &BB = *BI; 82 83 // Create a new basic block and copy instructions into it! 84 BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix); 85 NewFunc->getBasicBlockList().push_back(CBB); 86 ValueMap[&BB] = CBB; // Add basic block mapping. 87 88 if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator())) 89 Returns.push_back(RI); 90 } 91 92 // Loop over all of the instructions in the function, fixing up operand 93 // references as we go. This uses ValueMap to do all the hard work. 94 // 95 for (Function::const_iterator BB = OldFunc->begin(), BE = OldFunc->end(); 96 BB != BE; ++BB) { 97 BasicBlock *NBB = cast<BasicBlock>(ValueMap[BB]); 98 99 // Loop over all instructions, fixing each one as we find it... 100 for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); ++II) 101 RemapInstruction(II, ValueMap); 102 } 103} 104 105/// CloneFunction - Return a copy of the specified function, but without 106/// embedding the function into another module. Also, any references specified 107/// in the ValueMap are changed to refer to their mapped value instead of the 108/// original one. If any of the arguments to the function are in the ValueMap, 109/// the arguments are deleted from the resultant function. The ValueMap is 110/// updated to include mappings from all of the instructions and basicblocks in 111/// the function from their old to new values. 112/// 113Function *CloneFunction(const Function *F, 114 std::map<const Value*, Value*> &ValueMap) { 115 std::vector<const Type*> ArgTypes; 116 117 // The user might be deleting arguments to the function by specifying them in 118 // the ValueMap. If so, we need to not add the arguments to the arg ty vector 119 // 120 for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 121 if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet? 122 ArgTypes.push_back(I->getType()); 123 124 // Create a new function type... 125 FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(), 126 ArgTypes, F->getFunctionType()->isVarArg()); 127 128 // Create the new function... 129 Function *NewF = new Function(FTy, F->getLinkage(), F->getName()); 130 131 // Loop over the arguments, copying the names of the mapped arguments over... 132 Function::aiterator DestI = NewF->abegin(); 133 for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 134 if (ValueMap.count(I) == 0) { // Is this argument preserved? 135 DestI->setName(I->getName()); // Copy the name over... 136 ValueMap[I] = DestI++; // Add mapping to ValueMap 137 } 138 139 std::vector<ReturnInst*> Returns; // Ignore returns cloned... 140 CloneFunctionInto(NewF, F, ValueMap, Returns); 141 return NewF; 142} 143