llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp - llvm-project - Git at Google

 //===-- RTDyldObjectLinkingLayer.cpp - RuntimeDyld backed ORC ObjectLayer -===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
 #include "llvm/Object/COFF.h"

 namespace {

 using namespace llvm;
 using namespace llvm::orc;

 class JITDylibSearchOrderResolver : public JITSymbolResolver {
 public:
   JITDylibSearchOrderResolver(MaterializationResponsibility &MR) : MR(MR) {}

   void lookup(const LookupSet &Symbols, OnResolvedFunction OnResolved) {
     auto &ES = MR.getTargetJITDylib().getExecutionSession();
     SymbolLookupSet InternedSymbols;

     // Intern the requested symbols: lookup takes interned strings.
     for (auto &S : Symbols)
       InternedSymbols.add(ES.intern(S));

     // Build an OnResolve callback to unwrap the interned strings and pass them
     // to the OnResolved callback.
     auto OnResolvedWithUnwrap =
         [OnResolved = std::move(OnResolved)](
             Expected<SymbolMap> InternedResult) mutable {
           if (!InternedResult) {
             OnResolved(InternedResult.takeError());
             return;
           }

           LookupResult Result;
           for (auto &KV : *InternedResult)
             Result[*KV.first] = std::move(KV.second);
           OnResolved(Result);
         };

     // Register dependencies for all symbols contained in this set.
     auto RegisterDependencies = [&](const SymbolDependenceMap &Deps) {
       MR.addDependenciesForAll(Deps);
     };

     JITDylibSearchOrder LinkOrder;
     MR.getTargetJITDylib().withLinkOrderDo(
         [&](const JITDylibSearchOrder &LO) { LinkOrder = LO; });
     ES.lookup(LookupKind::Static, LinkOrder, InternedSymbols,
               SymbolState::Resolved, std::move(OnResolvedWithUnwrap),
               RegisterDependencies);
   }

   Expected<LookupSet> getResponsibilitySet(const LookupSet &Symbols) {
     LookupSet Result;

     for (auto &KV : MR.getSymbols()) {
       if (Symbols.count(*KV.first))
         Result.insert(*KV.first);
     }

     return Result;
   }

 private:
   MaterializationResponsibility &MR;
 };

 } // end anonymous namespace

 namespace llvm {
 namespace orc {

 RTDyldObjectLinkingLayer::RTDyldObjectLinkingLayer(
     ExecutionSession &ES, GetMemoryManagerFunction GetMemoryManager)
     : ObjectLayer(ES), GetMemoryManager(GetMemoryManager) {}

 RTDyldObjectLinkingLayer::~RTDyldObjectLinkingLayer() {
   std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
   for (auto &MemMgr : MemMgrs) {
     for (auto *L : EventListeners)
       L->notifyFreeingObject(
           static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr.get())));
     MemMgr->deregisterEHFrames();
   }
 }

 void RTDyldObjectLinkingLayer::emit(MaterializationResponsibility R,
                                     std::unique_ptr<MemoryBuffer> O) {
   assert(O && "Object must not be null");

   // This method launches an asynchronous link step that will fulfill our
   // materialization responsibility. We need to switch R to be heap
   // allocated before that happens so it can live as long as the asynchronous
   // link needs it to (i.e. it must be able to outlive this method).
   auto SharedR = std::make_shared<MaterializationResponsibility>(std::move(R));

   auto &ES = getExecutionSession();

   auto Obj = object::ObjectFile::createObjectFile(*O);

   if (!Obj) {
     getExecutionSession().reportError(Obj.takeError());
     SharedR->failMaterialization();
     return;
   }

   // Collect the internal symbols from the object file: We will need to
   // filter these later.
   auto InternalSymbols = std::make_shared<std::set<StringRef>>();
   {
     for (auto &Sym : (*Obj)->symbols()) {

       // Skip file symbols.
       if (auto SymType = Sym.getType()) {
         if (*SymType == object::SymbolRef::ST_File)
           continue;
       } else {
         ES.reportError(SymType.takeError());
         R.failMaterialization();
         return;
       }

       Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
       if (!SymFlagsOrErr) {
         // TODO: Test this error.
         ES.reportError(SymFlagsOrErr.takeError());
         R.failMaterialization();
         return;
       }

       // Don't include symbols that aren't global.
       if (!(*SymFlagsOrErr & object::BasicSymbolRef::SF_Global)) {
         if (auto SymName = Sym.getName())
           InternalSymbols->insert(*SymName);
         else {
           ES.reportError(SymName.takeError());
           R.failMaterialization();
           return;
         }
       }
     }
   }

   auto K = R.getVModuleKey();
   RuntimeDyld::MemoryManager *MemMgr = nullptr;

   // Create a record a memory manager for this object.
   {
     auto Tmp = GetMemoryManager();
     std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
     MemMgrs.push_back(std::move(Tmp));
     MemMgr = MemMgrs.back().get();
   }

   JITDylibSearchOrderResolver Resolver(*SharedR);

   jitLinkForORC(
       object::OwningBinary<object::ObjectFile>(std::move(*Obj), std::move(O)),
       *MemMgr, Resolver, ProcessAllSections,
       [this, K, SharedR, MemMgr, InternalSymbols](
           const object::ObjectFile &Obj,
           std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
           std::map<StringRef, JITEvaluatedSymbol> ResolvedSymbols) {
         return onObjLoad(K, *SharedR, Obj, MemMgr, std::move(LoadedObjInfo),
                          ResolvedSymbols, *InternalSymbols);
       },
       [this, K, SharedR, MemMgr](object::OwningBinary<object::ObjectFile> Obj,
                                  Error Err) mutable {
         onObjEmit(K, *SharedR, std::move(Obj), MemMgr, std::move(Err));
       });
 }

 void RTDyldObjectLinkingLayer::registerJITEventListener(JITEventListener &L) {
   std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
   assert(llvm::none_of(EventListeners,
                        [&](JITEventListener *O) { return O == &L; }) &&
          "Listener has already been registered");
   EventListeners.push_back(&L);
 }

 void RTDyldObjectLinkingLayer::unregisterJITEventListener(JITEventListener &L) {
   std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
   auto I = llvm::find(EventListeners, &L);
   assert(I != EventListeners.end() && "Listener not registered");
   EventListeners.erase(I);
 }

 Error RTDyldObjectLinkingLayer::onObjLoad(
     VModuleKey K, MaterializationResponsibility &R,
     const object::ObjectFile &Obj, RuntimeDyld::MemoryManager *MemMgr,
     std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
     std::map<StringRef, JITEvaluatedSymbol> Resolved,
     std::set<StringRef> &InternalSymbols) {
   SymbolFlagsMap ExtraSymbolsToClaim;
   SymbolMap Symbols;

   // Hack to support COFF constant pool comdats introduced during compilation:
   // (See http://llvm.org/PR40074)
   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(&Obj)) {
     auto &ES = getExecutionSession();

     // For all resolved symbols that are not already in the responsibilty set:
     // check whether the symbol is in a comdat section and if so mark it as
     // weak.
     for (auto &Sym : COFFObj->symbols()) {
       // getFlags() on COFF symbols can't fail.
       uint32_t SymFlags = cantFail(Sym.getFlags());
       if (SymFlags & object::BasicSymbolRef::SF_Undefined)
         continue;
       auto Name = Sym.getName();
       if (!Name)
         return Name.takeError();
       auto I = Resolved.find(*Name);

       // Skip unresolved symbols, internal symbols, and symbols that are
       // already in the responsibility set.
       if (I == Resolved.end() || InternalSymbols.count(*Name) ||
           R.getSymbols().count(ES.intern(*Name)))
         continue;
       auto Sec = Sym.getSection();
       if (!Sec)
         return Sec.takeError();
       if (*Sec == COFFObj->section_end())
         continue;
       auto &COFFSec = *COFFObj->getCOFFSection(**Sec);
       if (COFFSec.Characteristics & COFF::IMAGE_SCN_LNK_COMDAT)
         I->second.setFlags(I->second.getFlags() | JITSymbolFlags::Weak);
     }
   }

   for (auto &KV : Resolved) {
     // Scan the symbols and add them to the Symbols map for resolution.

     // We never claim internal symbols.
     if (InternalSymbols.count(KV.first))
       continue;

     auto InternedName = getExecutionSession().intern(KV.first);
     auto Flags = KV.second.getFlags();

     // Override object flags and claim responsibility for symbols if
     // requested.
     if (OverrideObjectFlags || AutoClaimObjectSymbols) {
       auto I = R.getSymbols().find(InternedName);

       if (OverrideObjectFlags && I != R.getSymbols().end())
         Flags = I->second;
       else if (AutoClaimObjectSymbols && I == R.getSymbols().end())
         ExtraSymbolsToClaim[InternedName] = Flags;
     }

     Symbols[InternedName] = JITEvaluatedSymbol(KV.second.getAddress(), Flags);
   }

   if (!ExtraSymbolsToClaim.empty()) {
     if (auto Err = R.defineMaterializing(ExtraSymbolsToClaim))
       return Err;

     // If we claimed responsibility for any weak symbols but were rejected then
     // we need to remove them from the resolved set.
     for (auto &KV : ExtraSymbolsToClaim)
       if (KV.second.isWeak() && !R.getSymbols().count(KV.first))
         Symbols.erase(KV.first);
   }

   if (auto Err = R.notifyResolved(Symbols)) {
     R.failMaterialization();
     return Err;
   }

   if (NotifyLoaded)
     NotifyLoaded(K, Obj, *LoadedObjInfo);

   std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
   assert(!LoadedObjInfos.count(MemMgr) && "Duplicate loaded info for MemMgr");
   LoadedObjInfos[MemMgr] = std::move(LoadedObjInfo);

   return Error::success();
 }

 void RTDyldObjectLinkingLayer::onObjEmit(
     VModuleKey K, MaterializationResponsibility &R,
     object::OwningBinary<object::ObjectFile> O,
     RuntimeDyld::MemoryManager *MemMgr, Error Err) {
   if (Err) {
     getExecutionSession().reportError(std::move(Err));
     R.failMaterialization();
     return;
   }

   if (auto Err = R.notifyEmitted()) {
     getExecutionSession().reportError(std::move(Err));
     R.failMaterialization();
     return;
   }

   std::unique_ptr<object::ObjectFile> Obj;
   std::unique_ptr<MemoryBuffer> ObjBuffer;
   std::tie(Obj, ObjBuffer) = O.takeBinary();

   // Run EventListener notifyLoaded callbacks.
   {
     std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
     auto LOIItr = LoadedObjInfos.find(MemMgr);
     assert(LOIItr != LoadedObjInfos.end() && "LoadedObjInfo missing");
     for (auto *L : EventListeners)
       L->notifyObjectLoaded(
           static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr)), *Obj,
           *LOIItr->second);
     LoadedObjInfos.erase(MemMgr);
   }

   if (NotifyEmitted)
     NotifyEmitted(K, std::move(ObjBuffer));
 }

 LegacyRTDyldObjectLinkingLayer::LegacyRTDyldObjectLinkingLayer(
     ExecutionSession &ES, ResourcesGetter GetResources,
     NotifyLoadedFtor NotifyLoaded, NotifyFinalizedFtor NotifyFinalized,
     NotifyFreedFtor NotifyFreed)
     : ES(ES), GetResources(std::move(GetResources)),
       NotifyLoaded(std::move(NotifyLoaded)),
       NotifyFinalized(std::move(NotifyFinalized)),
       NotifyFreed(std::move(NotifyFreed)), ProcessAllSections(false) {}

 } // End namespace orc.
 } // End namespace llvm.
	//===-- RTDyldObjectLinkingLayer.cpp - RuntimeDyld backed ORC ObjectLayer -===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
	#include "llvm/Object/COFF.h"

	namespace {

	using namespace llvm;
	using namespace llvm::orc;

	class JITDylibSearchOrderResolver : public JITSymbolResolver {
	public:
	JITDylibSearchOrderResolver(MaterializationResponsibility &MR) : MR(MR) {}

	void lookup(const LookupSet &Symbols, OnResolvedFunction OnResolved) {
	auto &ES = MR.getTargetJITDylib().getExecutionSession();
	SymbolLookupSet InternedSymbols;

	// Intern the requested symbols: lookup takes interned strings.
	for (auto &S : Symbols)
	InternedSymbols.add(ES.intern(S));

	// Build an OnResolve callback to unwrap the interned strings and pass them
	// to the OnResolved callback.
	auto OnResolvedWithUnwrap =
	[OnResolved = std::move(OnResolved)](
	Expected<SymbolMap> InternedResult) mutable {
	if (!InternedResult) {
	OnResolved(InternedResult.takeError());
	return;
	}

	LookupResult Result;
	for (auto &KV : *InternedResult)
	Result[*KV.first] = std::move(KV.second);
	OnResolved(Result);
	};

	// Register dependencies for all symbols contained in this set.
	auto RegisterDependencies = [&](const SymbolDependenceMap &Deps) {
	MR.addDependenciesForAll(Deps);
	};

	JITDylibSearchOrder LinkOrder;
	MR.getTargetJITDylib().withLinkOrderDo(
	[&](const JITDylibSearchOrder &LO) { LinkOrder = LO; });
	ES.lookup(LookupKind::Static, LinkOrder, InternedSymbols,
	SymbolState::Resolved, std::move(OnResolvedWithUnwrap),
	RegisterDependencies);
	}

	Expected<LookupSet> getResponsibilitySet(const LookupSet &Symbols) {
	LookupSet Result;

	for (auto &KV : MR.getSymbols()) {
	if (Symbols.count(*KV.first))
	Result.insert(*KV.first);
	}

	return Result;
	}

	private:
	MaterializationResponsibility &MR;
	};

	} // end anonymous namespace

	namespace llvm {
	namespace orc {

	RTDyldObjectLinkingLayer::RTDyldObjectLinkingLayer(
	ExecutionSession &ES, GetMemoryManagerFunction GetMemoryManager)
	: ObjectLayer(ES), GetMemoryManager(GetMemoryManager) {}

	RTDyldObjectLinkingLayer::~RTDyldObjectLinkingLayer() {
	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	for (auto &MemMgr : MemMgrs) {
	for (auto *L : EventListeners)
	L->notifyFreeingObject(
	static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr.get())));
	MemMgr->deregisterEHFrames();
	}
	}

	void RTDyldObjectLinkingLayer::emit(MaterializationResponsibility R,
	std::unique_ptr<MemoryBuffer> O) {
	assert(O && "Object must not be null");

	// This method launches an asynchronous link step that will fulfill our
	// materialization responsibility. We need to switch R to be heap
	// allocated before that happens so it can live as long as the asynchronous
	// link needs it to (i.e. it must be able to outlive this method).
	auto SharedR = std::make_shared<MaterializationResponsibility>(std::move(R));

	auto &ES = getExecutionSession();

	auto Obj = object::ObjectFile::createObjectFile(*O);

	if (!Obj) {
	getExecutionSession().reportError(Obj.takeError());
	SharedR->failMaterialization();
	return;
	}

	// Collect the internal symbols from the object file: We will need to
	// filter these later.
	auto InternalSymbols = std::make_shared<std::set<StringRef>>();
	{
	for (auto &Sym : (*Obj)->symbols()) {

	// Skip file symbols.
	if (auto SymType = Sym.getType()) {
	if (*SymType == object::SymbolRef::ST_File)
	continue;
	} else {
	ES.reportError(SymType.takeError());
	R.failMaterialization();
	return;
	}

	Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
	if (!SymFlagsOrErr) {
	// TODO: Test this error.
	ES.reportError(SymFlagsOrErr.takeError());
	R.failMaterialization();
	return;
	}

	// Don't include symbols that aren't global.
	if (!(*SymFlagsOrErr & object::BasicSymbolRef::SF_Global)) {
	if (auto SymName = Sym.getName())
	InternalSymbols->insert(*SymName);
	else {
	ES.reportError(SymName.takeError());
	R.failMaterialization();
	return;
	}
	}
	}
	}

	auto K = R.getVModuleKey();
	RuntimeDyld::MemoryManager *MemMgr = nullptr;

	// Create a record a memory manager for this object.
	{
	auto Tmp = GetMemoryManager();
	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	MemMgrs.push_back(std::move(Tmp));
	MemMgr = MemMgrs.back().get();
	}

	JITDylibSearchOrderResolver Resolver(*SharedR);

	jitLinkForORC(
	object::OwningBinary<object::ObjectFile>(std::move(*Obj), std::move(O)),
	*MemMgr, Resolver, ProcessAllSections,
	[this, K, SharedR, MemMgr, InternalSymbols](
	const object::ObjectFile &Obj,
	std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
	std::map<StringRef, JITEvaluatedSymbol> ResolvedSymbols) {
	return onObjLoad(K, *SharedR, Obj, MemMgr, std::move(LoadedObjInfo),
	ResolvedSymbols, *InternalSymbols);
	},
	[this, K, SharedR, MemMgr](object::OwningBinary<object::ObjectFile> Obj,
	Error Err) mutable {
	onObjEmit(K, *SharedR, std::move(Obj), MemMgr, std::move(Err));
	});
	}

	void RTDyldObjectLinkingLayer::registerJITEventListener(JITEventListener &L) {
	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	assert(llvm::none_of(EventListeners,
	[&](JITEventListener *O) { return O == &L; }) &&
	"Listener has already been registered");
	EventListeners.push_back(&L);
	}

	void RTDyldObjectLinkingLayer::unregisterJITEventListener(JITEventListener &L) {
	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	auto I = llvm::find(EventListeners, &L);
	assert(I != EventListeners.end() && "Listener not registered");
	EventListeners.erase(I);
	}

	Error RTDyldObjectLinkingLayer::onObjLoad(
	VModuleKey K, MaterializationResponsibility &R,
	const object::ObjectFile &Obj, RuntimeDyld::MemoryManager *MemMgr,
	std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
	std::map<StringRef, JITEvaluatedSymbol> Resolved,
	std::set<StringRef> &InternalSymbols) {
	SymbolFlagsMap ExtraSymbolsToClaim;
	SymbolMap Symbols;

	// Hack to support COFF constant pool comdats introduced during compilation:
	// (See http://llvm.org/PR40074)
	if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(&Obj)) {
	auto &ES = getExecutionSession();

	// For all resolved symbols that are not already in the responsibilty set:
	// check whether the symbol is in a comdat section and if so mark it as
	// weak.
	for (auto &Sym : COFFObj->symbols()) {
	// getFlags() on COFF symbols can't fail.
	uint32_t SymFlags = cantFail(Sym.getFlags());
	if (SymFlags & object::BasicSymbolRef::SF_Undefined)
	continue;
	auto Name = Sym.getName();
	if (!Name)
	return Name.takeError();
	auto I = Resolved.find(*Name);

	// Skip unresolved symbols, internal symbols, and symbols that are
	// already in the responsibility set.
	if (I == Resolved.end() \|\| InternalSymbols.count(*Name) \|\|
	R.getSymbols().count(ES.intern(*Name)))
	continue;
	auto Sec = Sym.getSection();
	if (!Sec)
	return Sec.takeError();
	if (*Sec == COFFObj->section_end())
	continue;
	auto &COFFSec = COFFObj->getCOFFSection(*Sec);
	if (COFFSec.Characteristics & COFF::IMAGE_SCN_LNK_COMDAT)
	I->second.setFlags(I->second.getFlags() \| JITSymbolFlags::Weak);
	}
	}

	for (auto &KV : Resolved) {
	// Scan the symbols and add them to the Symbols map for resolution.

	// We never claim internal symbols.
	if (InternalSymbols.count(KV.first))
	continue;

	auto InternedName = getExecutionSession().intern(KV.first);
	auto Flags = KV.second.getFlags();

	// Override object flags and claim responsibility for symbols if
	// requested.
	if (OverrideObjectFlags \|\| AutoClaimObjectSymbols) {
	auto I = R.getSymbols().find(InternedName);

	if (OverrideObjectFlags && I != R.getSymbols().end())
	Flags = I->second;
	else if (AutoClaimObjectSymbols && I == R.getSymbols().end())
	ExtraSymbolsToClaim[InternedName] = Flags;
	}

	Symbols[InternedName] = JITEvaluatedSymbol(KV.second.getAddress(), Flags);
	}

	if (!ExtraSymbolsToClaim.empty()) {
	if (auto Err = R.defineMaterializing(ExtraSymbolsToClaim))
	return Err;

	// If we claimed responsibility for any weak symbols but were rejected then
	// we need to remove them from the resolved set.
	for (auto &KV : ExtraSymbolsToClaim)
	if (KV.second.isWeak() && !R.getSymbols().count(KV.first))
	Symbols.erase(KV.first);
	}

	if (auto Err = R.notifyResolved(Symbols)) {
	R.failMaterialization();
	return Err;
	}

	if (NotifyLoaded)
	NotifyLoaded(K, Obj, *LoadedObjInfo);

	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	assert(!LoadedObjInfos.count(MemMgr) && "Duplicate loaded info for MemMgr");
	LoadedObjInfos[MemMgr] = std::move(LoadedObjInfo);

	return Error::success();
	}

	void RTDyldObjectLinkingLayer::onObjEmit(
	VModuleKey K, MaterializationResponsibility &R,
	object::OwningBinary<object::ObjectFile> O,
	RuntimeDyld::MemoryManager *MemMgr, Error Err) {
	if (Err) {
	getExecutionSession().reportError(std::move(Err));
	R.failMaterialization();
	return;
	}

	if (auto Err = R.notifyEmitted()) {
	getExecutionSession().reportError(std::move(Err));
	R.failMaterialization();
	return;
	}

	std::unique_ptr<object::ObjectFile> Obj;
	std::unique_ptr<MemoryBuffer> ObjBuffer;
	std::tie(Obj, ObjBuffer) = O.takeBinary();

	// Run EventListener notifyLoaded callbacks.
	{
	std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
	auto LOIItr = LoadedObjInfos.find(MemMgr);
	assert(LOIItr != LoadedObjInfos.end() && "LoadedObjInfo missing");
	for (auto *L : EventListeners)
	L->notifyObjectLoaded(
	static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr)), *Obj,
	*LOIItr->second);
	LoadedObjInfos.erase(MemMgr);
	}

	if (NotifyEmitted)
	NotifyEmitted(K, std::move(ObjBuffer));
	}

	LegacyRTDyldObjectLinkingLayer::LegacyRTDyldObjectLinkingLayer(
	ExecutionSession &ES, ResourcesGetter GetResources,
	NotifyLoadedFtor NotifyLoaded, NotifyFinalizedFtor NotifyFinalized,
	NotifyFreedFtor NotifyFreed)
	: ES(ES), GetResources(std::move(GetResources)),
	NotifyLoaded(std::move(NotifyLoaded)),
	NotifyFinalized(std::move(NotifyFinalized)),
	NotifyFreed(std::move(NotifyFreed)), ProcessAllSections(false) {}

	} // End namespace orc.
	} // End namespace llvm.