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