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//===-- 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 SearchOrder;
MR.getTargetJITDylib().withSearchOrderDo(
[&](const JITDylibSearchOrder &JDs) { SearchOrder = JDs; });
ES.lookup(LookupKind::Static, SearchOrder, 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)
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();
// Create a MemoryBufferRef backed MemoryBuffer (i.e. shallow) copy of the
// the underlying buffer to pass into RuntimeDyld. This allows us to hold
// ownership of the real underlying buffer and return it to the user once
// the object has been emitted.
auto ObjBuffer = MemoryBuffer::getMemBuffer(O->getMemBufferRef(), false);
auto Obj = object::ObjectFile::createObjectFile(*ObjBuffer);
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()) {
if (!(Sym.getFlags() & 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(
**Obj, std::move(O), *MemMgr, Resolver, ProcessAllSections,
[this, K, SharedR, &Obj, InternalSymbols](
std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
std::map<StringRef, JITEvaluatedSymbol> ResolvedSymbols) {
return onObjLoad(K, *SharedR, **Obj, std::move(LoadedObjInfo),
ResolvedSymbols, *InternalSymbols);
},
[this, K, SharedR, O = std::move(O)](Error Err) mutable {
onObjEmit(K, std::move(O), *SharedR, std::move(Err));
});
}
Error RTDyldObjectLinkingLayer::onObjLoad(
VModuleKey K, MaterializationResponsibility &R, object::ObjectFile &Obj,
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()) {
if (Sym.getFlags() & 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);
return Error::success();
}
void RTDyldObjectLinkingLayer::onObjEmit(
VModuleKey K, std::unique_ptr<MemoryBuffer> ObjBuffer,
MaterializationResponsibility &R, 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;
}
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.