std::unique_ptr<Module> llvm::CloneModule( const Module *M, ValueToValueMapTy &VMap, function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) { // First off, we need to create the new module. std::unique_ptr<Module> New = llvm::make_unique<Module>(M->getModuleIdentifier(), M->getContext()); New->setDataLayout(M->getDataLayout()); New->setTargetTriple(M->getTargetTriple()); New->setModuleInlineAsm(M->getModuleInlineAsm()); // Loop over all of the global variables, making corresponding globals in the // new module. Here we add them to the VMap and to the new Module. We // don't worry about attributes or initializers, they will come later. // for (Module::const_global_iterator I = M->global_begin(), E = M->global_end(); I != E; ++I) { GlobalVariable *GV = new GlobalVariable(*New, I->getValueType(), I->isConstant(), I->getLinkage(), (Constant*) nullptr, I->getName(), (GlobalVariable*) nullptr, I->getThreadLocalMode(), I->getType()->getAddressSpace()); GV->copyAttributesFrom(&*I); VMap[&*I] = GV; } // Loop over the functions in the module, making external functions as before for (const Function &I : *M) { Function *NF = Function::Create(cast<FunctionType>(I.getValueType()), I.getLinkage(), I.getName(), New.get()); NF->copyAttributesFrom(&I); VMap[&I] = NF; } // Loop over the aliases in the module for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end(); I != E; ++I) { if (!ShouldCloneDefinition(&*I)) { // An alias cannot act as an external reference, so we need to create // either a function or a global variable depending on the value type. // FIXME: Once pointee types are gone we can probably pick one or the // other. GlobalValue *GV; if (I->getValueType()->isFunctionTy()) GV = Function::Create(cast<FunctionType>(I->getValueType()), GlobalValue::ExternalLinkage, I->getName(), New.get()); else GV = new GlobalVariable( *New, I->getValueType(), false, GlobalValue::ExternalLinkage, (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr, I->getThreadLocalMode(), I->getType()->getAddressSpace()); VMap[&*I] = GV; // We do not copy attributes (mainly because copying between different // kinds of globals is forbidden), but this is generally not required for // correctness. continue; } auto *GA = GlobalAlias::create(I->getValueType(), I->getType()->getPointerAddressSpace(), I->getLinkage(), I->getName(), New.get()); GA->copyAttributesFrom(&*I); VMap[&*I] = GA; } // Now that all of the things that global variable initializer can refer to // have been created, loop through and copy the global variable referrers // over... We also set the attributes on the global now. // for (Module::const_global_iterator I = M->global_begin(), E = M->global_end(); I != E; ++I) { if (I->isDeclaration()) continue; GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]); if (!ShouldCloneDefinition(&*I)) { // Skip after setting the correct linkage for an external reference. GV->setLinkage(GlobalValue::ExternalLinkage); continue; } if (I->hasInitializer()) GV->setInitializer(MapValue(I->getInitializer(), VMap)); SmallVector<std::pair<unsigned, MDNode *>, 1> MDs; I->getAllMetadata(MDs); for (auto MD : MDs) GV->addMetadata(MD.first, *MapMetadata(MD.second, VMap)); } // Similarly, copy over function bodies now... // for (const Function &I : *M) { if (I.isDeclaration()) continue; Function *F = cast<Function>(VMap[&I]); if (!ShouldCloneDefinition(&I)) { // Skip after setting the correct linkage for an external reference. F->setLinkage(GlobalValue::ExternalLinkage); // Personality function is not valid on a declaration. F->setPersonalityFn(nullptr); continue; } Function::arg_iterator DestI = F->arg_begin(); for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end(); ++J) { DestI->setName(J->getName()); VMap[&*J] = &*DestI++; } SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned. CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns); if (I.hasPersonalityFn()) F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap)); } // And aliases for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end(); I != E; ++I) { // We already dealt with undefined aliases above. if (!ShouldCloneDefinition(&*I)) continue; GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]); if (const Constant *C = I->getAliasee()) GA->setAliasee(MapValue(C, VMap)); } // And named metadata.... for (Module::const_named_metadata_iterator I = M->named_metadata_begin(), E = M->named_metadata_end(); I != E; ++I) { const NamedMDNode &NMD = *I; NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName()); for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i) NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap)); } return New; }