llvm-project/llvm/lib/Transforms/Utils/CloneFunction.cpp

122 lines
5.2 KiB
C++

//===- CloneFunction.cpp - Clone a function into another function ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the CloneFunctionInto interface, which is used as the
// low-level function cloner. This is used by the CloneFunction and function
// inliner to do the dirty work of copying the body of a function around.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Instructions.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "ValueMapper.h"
using namespace llvm;
// CloneBasicBlock - See comments in Cloning.h
BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
std::map<const Value*, Value*> &ValueMap,
const char *NameSuffix, Function *F) {
BasicBlock *NewBB = new BasicBlock("", F);
if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
// Loop over all instructions copying them over...
for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
II != IE; ++II) {
Instruction *NewInst = II->clone();
if (II->hasName())
NewInst->setName(II->getName()+NameSuffix);
NewBB->getInstList().push_back(NewInst);
ValueMap[II] = NewInst; // Add instruction map to value.
}
return NewBB;
}
// Clone OldFunc into NewFunc, transforming the old arguments into references to
// ArgMap values.
//
void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
std::map<const Value*, Value*> &ValueMap,
std::vector<ReturnInst*> &Returns,
const char *NameSuffix) {
assert(NameSuffix && "NameSuffix cannot be null!");
#ifndef NDEBUG
for (Function::const_aiterator I = OldFunc->abegin(), E = OldFunc->aend();
I != E; ++I)
assert(ValueMap.count(I) && "No mapping from source argument specified!");
#endif
// Loop over all of the basic blocks in the function, cloning them as
// appropriate. Note that we save BE this way in order to handle cloning of
// recursive functions into themselves.
//
for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
BI != BE; ++BI) {
const BasicBlock &BB = *BI;
// Create a new basic block and copy instructions into it!
BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix, NewFunc);
ValueMap[&BB] = CBB; // Add basic block mapping.
if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
Returns.push_back(RI);
}
// Loop over all of the instructions in the function, fixing up operand
// references as we go. This uses ValueMap to do all the hard work.
//
for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]),
BE = NewFunc->end(); BB != BE; ++BB)
// Loop over all instructions, fixing each one as we find it...
for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
RemapInstruction(II, ValueMap);
}
/// CloneFunction - Return a copy of the specified function, but without
/// embedding the function into another module. Also, any references specified
/// in the ValueMap are changed to refer to their mapped value instead of the
/// original one. If any of the arguments to the function are in the ValueMap,
/// the arguments are deleted from the resultant function. The ValueMap is
/// updated to include mappings from all of the instructions and basicblocks in
/// the function from their old to new values.
///
Function *llvm::CloneFunction(const Function *F,
std::map<const Value*, Value*> &ValueMap) {
std::vector<const Type*> ArgTypes;
// The user might be deleting arguments to the function by specifying them in
// the ValueMap. If so, we need to not add the arguments to the arg ty vector
//
for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I)
if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet?
ArgTypes.push_back(I->getType());
// Create a new function type...
FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(),
ArgTypes, F->getFunctionType()->isVarArg());
// Create the new function...
Function *NewF = new Function(FTy, F->getLinkage(), F->getName());
// Loop over the arguments, copying the names of the mapped arguments over...
Function::aiterator DestI = NewF->abegin();
for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I)
if (ValueMap.count(I) == 0) { // Is this argument preserved?
DestI->setName(I->getName()); // Copy the name over...
ValueMap[I] = DestI++; // Add mapping to ValueMap
}
std::vector<ReturnInst*> Returns; // Ignore returns cloned...
CloneFunctionInto(NewF, F, ValueMap, Returns);
return NewF;
}