1 //===- CloneModule.cpp - Clone an entire module ---------------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file implements the CloneModule interface which makes a copy of an
12 //===----------------------------------------------------------------------===//
14 #include "llvm/IR/DerivedTypes.h"
15 #include "llvm/IR/Module.h"
16 #include "llvm/Transforms/Utils/Cloning.h"
17 #include "llvm/Transforms/Utils/ValueMapper.h"
24 static void copyComdat(GlobalObject *Dst, const GlobalObject *Src) {
25 const Comdat *SC = Src->getComdat();
28 Comdat *DC = Dst->getParent()->getOrInsertComdat(SC->getName());
29 DC->setSelectionKind(SC->getSelectionKind());
33 /// This is not as easy as it might seem because we have to worry about making
34 /// copies of global variables and functions, and making their (initializers and
35 /// references, respectively) refer to the right globals.
37 std::unique_ptr<Module> llvm::CloneModule(const Module &M) {
38 // Create the value map that maps things from the old module over to the new
40 ValueToValueMapTy VMap;
41 return CloneModule(M, VMap);
44 std::unique_ptr<Module> llvm::CloneModule(const Module &M,
45 ValueToValueMapTy &VMap) {
46 return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
49 std::unique_ptr<Module> llvm::CloneModule(
50 const Module &M, ValueToValueMapTy &VMap,
51 function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
52 // First off, we need to create the new module.
53 std::unique_ptr<Module> New =
54 std::make_unique<Module>(M.getModuleIdentifier(), M.getContext());
55 New->setSourceFileName(M.getSourceFileName());
56 New->setDataLayout(M.getDataLayout());
57 New->setTargetTriple(M.getTargetTriple());
58 New->setModuleInlineAsm(M.getModuleInlineAsm());
60 // Loop over all of the global variables, making corresponding globals in the
61 // new module. Here we add them to the VMap and to the new Module. We
62 // don't worry about attributes or initializers, they will come later.
64 for (const GlobalVariable &I : M.globals()) {
65 GlobalVariable *NewGV = new GlobalVariable(
66 *New, I.getValueType(), I.isConstant(), I.getLinkage(),
67 (Constant *)nullptr, I.getName(), (GlobalVariable *)nullptr,
68 I.getThreadLocalMode(), I.getType()->getAddressSpace());
69 NewGV->copyAttributesFrom(&I);
73 // Loop over the functions in the module, making external functions as before
74 for (const Function &I : M) {
76 Function::Create(cast<FunctionType>(I.getValueType()), I.getLinkage(),
77 I.getAddressSpace(), I.getName(), New.get());
78 NF->copyAttributesFrom(&I);
82 // Loop over the aliases in the module
83 for (const GlobalAlias &I : M.aliases()) {
84 if (!ShouldCloneDefinition(&I)) {
85 // An alias cannot act as an external reference, so we need to create
86 // either a function or a global variable depending on the value type.
87 // FIXME: Once pointee types are gone we can probably pick one or the
90 if (I.getValueType()->isFunctionTy())
91 GV = Function::Create(cast<FunctionType>(I.getValueType()),
92 GlobalValue::ExternalLinkage, I.getAddressSpace(),
93 I.getName(), New.get());
95 GV = new GlobalVariable(*New, I.getValueType(), false,
96 GlobalValue::ExternalLinkage, nullptr,
97 I.getName(), nullptr, I.getThreadLocalMode(),
98 I.getType()->getAddressSpace());
100 // We do not copy attributes (mainly because copying between different
101 // kinds of globals is forbidden), but this is generally not required for
105 auto *GA = GlobalAlias::create(I.getValueType(),
106 I.getType()->getPointerAddressSpace(),
107 I.getLinkage(), I.getName(), New.get());
108 GA->copyAttributesFrom(&I);
112 // Now that all of the things that global variable initializer can refer to
113 // have been created, loop through and copy the global variable referrers
114 // over... We also set the attributes on the global now.
116 for (const GlobalVariable &G : M.globals()) {
117 GlobalVariable *GV = cast<GlobalVariable>(VMap[&G]);
119 SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
120 G.getAllMetadata(MDs);
122 GV->addMetadata(MD.first, *MapMetadata(MD.second, VMap));
124 if (G.isDeclaration())
127 if (!ShouldCloneDefinition(&G)) {
128 // Skip after setting the correct linkage for an external reference.
129 GV->setLinkage(GlobalValue::ExternalLinkage);
132 if (G.hasInitializer())
133 GV->setInitializer(MapValue(G.getInitializer(), VMap));
138 // Similarly, copy over function bodies now...
140 for (const Function &I : M) {
141 Function *F = cast<Function>(VMap[&I]);
143 if (I.isDeclaration()) {
144 // Copy over metadata for declarations since we're not doing it below in
145 // CloneFunctionInto().
146 SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
147 I.getAllMetadata(MDs);
149 F->addMetadata(MD.first, *MapMetadata(MD.second, VMap));
153 if (!ShouldCloneDefinition(&I)) {
154 // Skip after setting the correct linkage for an external reference.
155 F->setLinkage(GlobalValue::ExternalLinkage);
156 // Personality function is not valid on a declaration.
157 F->setPersonalityFn(nullptr);
161 Function::arg_iterator DestI = F->arg_begin();
162 for (const Argument &J : I.args()) {
163 DestI->setName(J.getName());
164 VMap[&J] = &*DestI++;
167 SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
168 CloneFunctionInto(F, &I, VMap, CloneFunctionChangeType::ClonedModule,
171 if (I.hasPersonalityFn())
172 F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
178 for (const GlobalAlias &I : M.aliases()) {
179 // We already dealt with undefined aliases above.
180 if (!ShouldCloneDefinition(&I))
182 GlobalAlias *GA = cast<GlobalAlias>(VMap[&I]);
183 if (const Constant *C = I.getAliasee())
184 GA->setAliasee(MapValue(C, VMap));
187 // And named metadata....
188 for (const NamedMDNode &NMD : M.named_metadata()) {
189 NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
190 for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
191 NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
199 LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
200 return wrap(CloneModule(*unwrap(M)).release());