1 //===- CloneModule.cpp - Clone an entire module ---------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the CloneModule interface which makes a copy of an
13 //===----------------------------------------------------------------------===//
15 #include "llvm/IR/Constant.h"
16 #include "llvm/IR/DerivedTypes.h"
17 #include "llvm/IR/Module.h"
18 #include "llvm/Transforms/Utils/Cloning.h"
19 #include "llvm/Transforms/Utils/ValueMapper.h"
22 static void copyComdat(GlobalObject *Dst, const GlobalObject *Src) {
23 const Comdat *SC = Src->getComdat();
26 Comdat *DC = Dst->getParent()->getOrInsertComdat(SC->getName());
27 DC->setSelectionKind(SC->getSelectionKind());
31 /// This is not as easy as it might seem because we have to worry about making
32 /// copies of global variables and functions, and making their (initializers and
33 /// references, respectively) refer to the right globals.
35 std::unique_ptr<Module> llvm::CloneModule(const Module *M) {
36 // Create the value map that maps things from the old module over to the new
38 ValueToValueMapTy VMap;
39 return CloneModule(M, VMap);
42 std::unique_ptr<Module> llvm::CloneModule(const Module *M,
43 ValueToValueMapTy &VMap) {
44 return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
47 std::unique_ptr<Module> llvm::CloneModule(
48 const Module *M, ValueToValueMapTy &VMap,
49 function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
50 // First off, we need to create the new module.
51 std::unique_ptr<Module> New =
52 llvm::make_unique<Module>(M->getModuleIdentifier(), M->getContext());
53 New->setDataLayout(M->getDataLayout());
54 New->setTargetTriple(M->getTargetTriple());
55 New->setModuleInlineAsm(M->getModuleInlineAsm());
57 // Loop over all of the global variables, making corresponding globals in the
58 // new module. Here we add them to the VMap and to the new Module. We
59 // don't worry about attributes or initializers, they will come later.
61 for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
63 GlobalVariable *GV = new GlobalVariable(*New,
65 I->isConstant(), I->getLinkage(),
66 (Constant*) nullptr, I->getName(),
67 (GlobalVariable*) nullptr,
68 I->getThreadLocalMode(),
69 I->getType()->getAddressSpace());
70 GV->copyAttributesFrom(&*I);
74 // Loop over the functions in the module, making external functions as before
75 for (const Function &I : *M) {
76 Function *NF = Function::Create(cast<FunctionType>(I.getValueType()),
77 I.getLinkage(), I.getName(), New.get());
78 NF->copyAttributesFrom(&I);
82 // Loop over the aliases in the module
83 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
85 if (!ShouldCloneDefinition(&*I)) {
86 // An alias cannot act as an external reference, so we need to create
87 // either a function or a global variable depending on the value type.
88 // FIXME: Once pointee types are gone we can probably pick one or the
91 if (I->getValueType()->isFunctionTy())
92 GV = Function::Create(cast<FunctionType>(I->getValueType()),
93 GlobalValue::ExternalLinkage, I->getName(),
96 GV = new GlobalVariable(
97 *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
98 nullptr, I->getName(), nullptr,
99 I->getThreadLocalMode(), I->getType()->getAddressSpace());
101 // We do not copy attributes (mainly because copying between different
102 // kinds of globals is forbidden), but this is generally not required for
106 auto *GA = GlobalAlias::create(I->getValueType(),
107 I->getType()->getPointerAddressSpace(),
108 I->getLinkage(), I->getName(), New.get());
109 GA->copyAttributesFrom(&*I);
113 // Now that all of the things that global variable initializer can refer to
114 // have been created, loop through and copy the global variable referrers
115 // over... We also set the attributes on the global now.
117 for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
119 if (I->isDeclaration())
122 GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
123 if (!ShouldCloneDefinition(&*I)) {
124 // Skip after setting the correct linkage for an external reference.
125 GV->setLinkage(GlobalValue::ExternalLinkage);
128 if (I->hasInitializer())
129 GV->setInitializer(MapValue(I->getInitializer(), VMap));
131 SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
132 I->getAllMetadata(MDs);
134 GV->addMetadata(MD.first,
135 *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
140 // Similarly, copy over function bodies now...
142 for (const Function &I : *M) {
143 if (I.isDeclaration())
146 Function *F = cast<Function>(VMap[&I]);
147 if (!ShouldCloneDefinition(&I)) {
148 // Skip after setting the correct linkage for an external reference.
149 F->setLinkage(GlobalValue::ExternalLinkage);
150 // Personality function is not valid on a declaration.
151 F->setPersonalityFn(nullptr);
155 Function::arg_iterator DestI = F->arg_begin();
156 for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
158 DestI->setName(J->getName());
159 VMap[&*J] = &*DestI++;
162 SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
163 CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns);
165 if (I.hasPersonalityFn())
166 F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
172 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
174 // We already dealt with undefined aliases above.
175 if (!ShouldCloneDefinition(&*I))
177 GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
178 if (const Constant *C = I->getAliasee())
179 GA->setAliasee(MapValue(C, VMap));
182 // And named metadata....
183 for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
184 E = M->named_metadata_end(); I != E; ++I) {
185 const NamedMDNode &NMD = *I;
186 NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
187 for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
188 NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
196 LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
197 return wrap(CloneModule(unwrap(M)).release());