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