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 /// CloneModule - Return an exact copy of the specified module. This is not as
24 /// easy as it might seem because we have to worry about making copies of global
25 /// variables and functions, and making their (initializers and references,
26 /// respectively) refer to the right globals.
28 Module *llvm::CloneModule(const Module *M) {
29 // Create the value map that maps things from the old module over to the new
31 ValueToValueMapTy VMap;
32 return CloneModule(M, VMap);
35 Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
36 return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
39 Module *llvm::CloneModule(
40 const Module *M, ValueToValueMapTy &VMap,
41 std::function<bool(const GlobalValue *)> ShouldCloneDefinition) {
42 // First off, we need to create the new module.
43 Module *New = new Module(M->getModuleIdentifier(), M->getContext());
44 New->setDataLayout(M->getDataLayout());
45 New->setTargetTriple(M->getTargetTriple());
46 New->setModuleInlineAsm(M->getModuleInlineAsm());
48 // Loop over all of the global variables, making corresponding globals in the
49 // new module. Here we add them to the VMap and to the new Module. We
50 // don't worry about attributes or initializers, they will come later.
52 for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
54 GlobalVariable *GV = new GlobalVariable(*New,
55 I->getType()->getElementType(),
56 I->isConstant(), I->getLinkage(),
57 (Constant*) nullptr, I->getName(),
58 (GlobalVariable*) nullptr,
59 I->getThreadLocalMode(),
60 I->getType()->getAddressSpace());
61 GV->copyAttributesFrom(I);
65 // Loop over the functions in the module, making external functions as before
66 for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
68 Function::Create(cast<FunctionType>(I->getType()->getElementType()),
69 I->getLinkage(), I->getName(), New);
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(), New);
87 GV = new GlobalVariable(
88 *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
89 (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr,
90 I->getThreadLocalMode(), I->getType()->getAddressSpace());
92 // We do not copy attributes (mainly because copying between different
93 // kinds of globals is forbidden), but this is generally not required for
97 auto *PTy = cast<PointerType>(I->getType());
99 GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
100 I->getLinkage(), I->getName(), New);
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 GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
112 if (!ShouldCloneDefinition(I)) {
113 // Skip after setting the correct linkage for an external reference.
114 GV->setLinkage(GlobalValue::ExternalLinkage);
117 if (I->hasInitializer())
118 GV->setInitializer(MapValue(I->getInitializer(), VMap));
121 // Similarly, copy over function bodies now...
123 for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
124 Function *F = cast<Function>(VMap[I]);
125 if (!ShouldCloneDefinition(I)) {
126 // Skip after setting the correct linkage for an external reference.
127 F->setLinkage(GlobalValue::ExternalLinkage);
130 if (!I->isDeclaration()) {
131 Function::arg_iterator DestI = F->arg_begin();
132 for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
134 DestI->setName(J->getName());
138 SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
139 CloneFunctionInto(F, I, VMap, /*ModuleLevelChanges=*/true, Returns);
143 if (I->hasPersonalityFn())
144 F->setPersonalityFn(MapValue(I->getPersonalityFn(), VMap));
148 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
150 // We already dealt with undefined aliases above.
151 if (!ShouldCloneDefinition(I))
153 GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
154 if (const Constant *C = I->getAliasee())
155 GA->setAliasee(MapValue(C, VMap));
158 // And named metadata....
159 for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
160 E = M->named_metadata_end(); I != E; ++I) {
161 const NamedMDNode &NMD = *I;
162 NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
163 for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
164 NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
172 LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
173 return wrap(CloneModule(unwrap(M)));