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/Transforms/Utils/Cloning.h"
16 #include "llvm/IR/Constant.h"
17 #include "llvm/IR/DerivedTypes.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/Transforms/Utils/ValueMapper.h"
20 #include "llvm-c/Core.h"
23 /// This is not as easy as it might seem because we have to worry about making
24 /// copies of global variables and functions, and making their (initializers and
25 /// references, respectively) refer to the right globals.
27 std::unique_ptr<Module> llvm::CloneModule(const Module *M) {
28 // Create the value map that maps things from the old module over to the new
30 ValueToValueMapTy VMap;
31 return CloneModule(M, VMap);
34 std::unique_ptr<Module> llvm::CloneModule(const Module *M,
35 ValueToValueMapTy &VMap) {
36 return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
39 std::unique_ptr<Module> llvm::CloneModule(
40 const Module *M, ValueToValueMapTy &VMap,
41 function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
42 // First off, we need to create the new module.
43 std::unique_ptr<Module> New =
44 llvm::make_unique<Module>(M->getModuleIdentifier(), M->getContext());
45 New->setDataLayout(M->getDataLayout());
46 New->setTargetTriple(M->getTargetTriple());
47 New->setModuleInlineAsm(M->getModuleInlineAsm());
49 // Loop over all of the global variables, making corresponding globals in the
50 // new module. Here we add them to the VMap and to the new Module. We
51 // don't worry about attributes or initializers, they will come later.
53 for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
55 GlobalVariable *GV = new GlobalVariable(*New,
57 I->isConstant(), I->getLinkage(),
58 (Constant*) nullptr, I->getName(),
59 (GlobalVariable*) nullptr,
60 I->getThreadLocalMode(),
61 I->getType()->getAddressSpace());
62 GV->copyAttributesFrom(&*I);
66 // Loop over the functions in the module, making external functions as before
67 for (const Function &I : *M) {
68 Function *NF = Function::Create(cast<FunctionType>(I.getValueType()),
69 I.getLinkage(), I.getName(), New.get());
70 NF->copyAttributesFrom(&I);
74 // Loop over the aliases in the module
75 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
77 if (!ShouldCloneDefinition(&*I)) {
78 // An alias cannot act as an external reference, so we need to create
79 // either a function or a global variable depending on the value type.
80 // FIXME: Once pointee types are gone we can probably pick one or the
83 if (I->getValueType()->isFunctionTy())
84 GV = Function::Create(cast<FunctionType>(I->getValueType()),
85 GlobalValue::ExternalLinkage, I->getName(),
88 GV = new GlobalVariable(
89 *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
90 (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr,
91 I->getThreadLocalMode(), I->getType()->getAddressSpace());
93 // We do not copy attributes (mainly because copying between different
94 // kinds of globals is forbidden), but this is generally not required for
98 auto *GA = GlobalAlias::create(I->getValueType(),
99 I->getType()->getPointerAddressSpace(),
100 I->getLinkage(), I->getName(), New.get());
101 GA->copyAttributesFrom(&*I);
105 // Now that all of the things that global variable initializer can refer to
106 // have been created, loop through and copy the global variable referrers
107 // over... We also set the attributes on the global now.
109 for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
111 if (I->isDeclaration())
114 GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
115 if (!ShouldCloneDefinition(&*I)) {
116 // Skip after setting the correct linkage for an external reference.
117 GV->setLinkage(GlobalValue::ExternalLinkage);
120 if (I->hasInitializer())
121 GV->setInitializer(MapValue(I->getInitializer(), VMap));
124 // Similarly, copy over function bodies now...
126 for (const Function &I : *M) {
127 if (I.isDeclaration())
130 Function *F = cast<Function>(VMap[&I]);
131 if (!ShouldCloneDefinition(&I)) {
132 // Skip after setting the correct linkage for an external reference.
133 F->setLinkage(GlobalValue::ExternalLinkage);
134 // Personality function is not valid on a declaration.
135 F->setPersonalityFn(nullptr);
139 Function::arg_iterator DestI = F->arg_begin();
140 for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
142 DestI->setName(J->getName());
143 VMap[&*J] = &*DestI++;
146 SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
147 CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns);
149 if (I.hasPersonalityFn())
150 F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
154 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
156 // We already dealt with undefined aliases above.
157 if (!ShouldCloneDefinition(&*I))
159 GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
160 if (const Constant *C = I->getAliasee())
161 GA->setAliasee(MapValue(C, VMap));
164 // And named metadata....
165 for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
166 E = M->named_metadata_end(); I != E; ++I) {
167 const NamedMDNode &NMD = *I;
168 NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
169 for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
170 NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
178 LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
179 return wrap(CloneModule(unwrap(M)).release());