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//===- CloneModule.cpp - Clone an entire module ---------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the CloneModule interface which makes a copy of an
// entire module.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Constant.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Module.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
using namespace llvm;
static void copyComdat(GlobalObject *Dst, const GlobalObject *Src) {
const Comdat *SC = Src->getComdat();
if (!SC)
return;
Comdat *DC = Dst->getParent()->getOrInsertComdat(SC->getName());
DC->setSelectionKind(SC->getSelectionKind());
Dst->setComdat(DC);
}
/// This is not as easy as it might seem because we have to worry about making
/// copies of global variables and functions, and making their (initializers and
/// references, respectively) refer to the right globals.
///
std::unique_ptr<Module> llvm::CloneModule(const Module &M) {
// Create the value map that maps things from the old module over to the new
// module.
ValueToValueMapTy VMap;
return CloneModule(M, VMap);
}
std::unique_ptr<Module> llvm::CloneModule(const Module &M,
ValueToValueMapTy &VMap) {
return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
}
std::unique_ptr<Module> llvm::CloneModule(
const Module &M, ValueToValueMapTy &VMap,
function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
// First off, we need to create the new module.
std::unique_ptr<Module> New =
std::make_unique<Module>(M.getModuleIdentifier(), M.getContext());
New->setSourceFileName(M.getSourceFileName());
New->setDataLayout(M.getDataLayout());
New->setTargetTriple(M.getTargetTriple());
New->setModuleInlineAsm(M.getModuleInlineAsm());
// Loop over all of the global variables, making corresponding globals in the
// new module. Here we add them to the VMap and to the new Module. We
// don't worry about attributes or initializers, they will come later.
//
for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I) {
GlobalVariable *GV = new GlobalVariable(*New,
I->getValueType(),
I->isConstant(), I->getLinkage(),
(Constant*) nullptr, I->getName(),
(GlobalVariable*) nullptr,
I->getThreadLocalMode(),
I->getType()->getAddressSpace());
GV->copyAttributesFrom(&*I);
VMap[&*I] = GV;
}
// Loop over the functions in the module, making external functions as before
for (const Function &I : M) {
Function *NF =
Function::Create(cast<FunctionType>(I.getValueType()), I.getLinkage(),
I.getAddressSpace(), I.getName(), New.get());
NF->copyAttributesFrom(&I);
VMap[&I] = NF;
}
// Loop over the aliases in the module
for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I) {
if (!ShouldCloneDefinition(&*I)) {
// An alias cannot act as an external reference, so we need to create
// either a function or a global variable depending on the value type.
// FIXME: Once pointee types are gone we can probably pick one or the
// other.
GlobalValue *GV;
if (I->getValueType()->isFunctionTy())
GV = Function::Create(cast<FunctionType>(I->getValueType()),
GlobalValue::ExternalLinkage,
I->getAddressSpace(), I->getName(), New.get());
else
GV = new GlobalVariable(
*New, I->getValueType(), false, GlobalValue::ExternalLinkage,
nullptr, I->getName(), nullptr,
I->getThreadLocalMode(), I->getType()->getAddressSpace());
VMap[&*I] = GV;
// We do not copy attributes (mainly because copying between different
// kinds of globals is forbidden), but this is generally not required for
// correctness.
continue;
}
auto *GA = GlobalAlias::create(I->getValueType(),
I->getType()->getPointerAddressSpace(),
I->getLinkage(), I->getName(), New.get());
GA->copyAttributesFrom(&*I);
VMap[&*I] = GA;
}
// Now that all of the things that global variable initializer can refer to
// have been created, loop through and copy the global variable referrers
// over... We also set the attributes on the global now.
//
for (const GlobalVariable &G : M.globals()) {
GlobalVariable *GV = cast<GlobalVariable>(VMap[&G]);
SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
G.getAllMetadata(MDs);
for (auto MD : MDs)
GV->addMetadata(MD.first, *MapMetadata(MD.second, VMap));
if (G.isDeclaration())
continue;
if (!ShouldCloneDefinition(&G)) {
// Skip after setting the correct linkage for an external reference.
GV->setLinkage(GlobalValue::ExternalLinkage);
continue;
}
if (G.hasInitializer())
GV->setInitializer(MapValue(G.getInitializer(), VMap));
copyComdat(GV, &G);
}
// Similarly, copy over function bodies now...
//
for (const Function &I : M) {
if (I.isDeclaration())
continue;
Function *F = cast<Function>(VMap[&I]);
if (!ShouldCloneDefinition(&I)) {
// Skip after setting the correct linkage for an external reference.
F->setLinkage(GlobalValue::ExternalLinkage);
// Personality function is not valid on a declaration.
F->setPersonalityFn(nullptr);
continue;
}
Function::arg_iterator DestI = F->arg_begin();
for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
++J) {
DestI->setName(J->getName());
VMap[&*J] = &*DestI++;
}
SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
CloneFunctionInto(F, &I, VMap, CloneFunctionChangeType::ClonedModule,
Returns);
if (I.hasPersonalityFn())
F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
copyComdat(F, &I);
}
// And aliases
for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I) {
// We already dealt with undefined aliases above.
if (!ShouldCloneDefinition(&*I))
continue;
GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
if (const Constant *C = I->getAliasee())
GA->setAliasee(MapValue(C, VMap));
}
// And named metadata....
for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
E = M.named_metadata_end();
I != E; ++I) {
const NamedMDNode &NMD = *I;
NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
}
return New;
}
extern "C" {
LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
return wrap(CloneModule(*unwrap(M)).release());
}
}
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