llvm::GlobalVariable* JitCodeSpecializer::_clone_global_variable(SpecializationContext& context,
const llvm::GlobalVariable& global_variable) const {
// If the global variable already exists in the module, there is no point in cloning it again
if (auto global = context.module->getGlobalVariable(global_variable.getName())) {
return global;
}
// Create a new global variable with the same type, attributes, and properties
const auto cloned_global = llvm::dyn_cast<llvm::GlobalVariable>(
context.module->getOrInsertGlobal(global_variable.getName(), global_variable.getValueType()));
cloned_global->setLinkage(global_variable.getLinkage());
cloned_global->setThreadLocalMode(global_variable.getThreadLocalMode());
cloned_global->copyAttributesFrom(&global_variable);
if (!global_variable.isDeclaration()) {
if (global_variable.hasInitializer()) {
// Instruct LLVM to perform the cloning of the actual value (i.e., initializer) of the variable
cloned_global->setInitializer(llvm::MapValue(global_variable.getInitializer(), context.llvm_value_map));
}
// Clone LLVM metadata for the global variable
llvm::SmallVector<std::pair<uint32_t, llvm::MDNode*>, 1> metadata_nodes;
global_variable.getAllMetadata(metadata_nodes);
for (const auto& metadata_node : metadata_nodes) {
cloned_global->addMetadata(metadata_node.first,
*MapMetadata(metadata_node.second, context.llvm_value_map, llvm::RF_MoveDistinctMDs));
}
}
return cloned_global;
}
void cloneModuleFlagsMetadata(Module &Dst, const Module &Src,
ValueToValueMapTy &VMap) {
auto *MFs = Src.getModuleFlagsMetadata();
if (!MFs)
return;
for (auto *MF : MFs->operands())
Dst.addModuleFlag(MapMetadata(MF, VMap));
}
void CloneSubModule(llvm::Module &Dst, const Module &Src,
HandleGlobalVariableFtor HandleGlobalVariable,
HandleFunctionFtor HandleFunction, bool CloneInlineAsm) {
ValueToValueMapTy VMap;
if (CloneInlineAsm)
Dst.appendModuleInlineAsm(Src.getModuleInlineAsm());
// Copy global variables (but not initializers, yet).
for (Module::const_global_iterator I = Src.global_begin(), E = Src.global_end();
I != E; ++I) {
GlobalVariable *GV = new GlobalVariable(
Dst, I->getType()->getElementType(), 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 (Module::const_iterator I = Src.begin(), E = Src.end(); I != E; ++I) {
Function *NF =
Function::Create(cast<FunctionType>(I->getType()->getElementType()),
I->getLinkage(), I->getName(), &Dst);
NF->copyAttributesFrom(I);
VMap[I] = NF;
}
// Loop over the aliases in the module
for (Module::const_alias_iterator I = Src.alias_begin(), E = Src.alias_end();
I != E; ++I) {
auto *PTy = cast<PointerType>(I->getType());
auto *GA =
GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
I->getLinkage(), I->getName(), &Dst);
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 = Src.global_begin(), E = Src.global_end();
I != E; ++I) {
GlobalVariable &GV = *cast<GlobalVariable>(VMap[I]);
HandleGlobalVariable(GV, *I, VMap);
}
// Similarly, copy over function bodies now...
//
for (Module::const_iterator I = Src.begin(), E = Src.end(); I != E; ++I) {
Function &F = *cast<Function>(VMap[I]);
HandleFunction(F, *I, VMap);
}
// And aliases
for (Module::const_alias_iterator I = Src.alias_begin(), E = Src.alias_end();
I != E; ++I) {
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 = Src.named_metadata_begin(),
E = Src.named_metadata_end();
I != E; ++I) {
const NamedMDNode &NMD = *I;
NamedMDNode *NewNMD = Dst.getOrInsertNamedMetadata(NMD.getName());
for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
}
}
