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| //===-- ObjectLinkingLayer.h - JITLink-based jit linking layer --*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Contains the definition for an JITLink-based, in-process object linking
// layer.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H
#define LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/JITLink/JITLink.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "llvm/ExecutionEngine/Orc/Layer.h"
#include "llvm/Support/Error.h"
#include <algorithm>
#include <cassert>
#include <functional>
#include <list>
#include <memory>
#include <string>
#include <utility>
#include <vector>
namespace llvm {
namespace jitlink {
class EHFrameRegistrar;
} // namespace jitlink
namespace object {
class ObjectFile;
} // namespace object
namespace orc {
class ObjectLinkingLayerJITLinkContext;
/// An ObjectLayer implementation built on JITLink.
///
/// Clients can use this class to add relocatable object files to an
/// ExecutionSession, and it typically serves as the base layer (underneath
/// a compiling layer like IRCompileLayer) for the rest of the JIT.
class ObjectLinkingLayer : public ObjectLayer {
friend class ObjectLinkingLayerJITLinkContext;
public:
/// Plugin instances can be added to the ObjectLinkingLayer to receive
/// callbacks when code is loaded or emitted, and when JITLink is being
/// configured.
class Plugin {
public:
virtual ~Plugin();
virtual void modifyPassConfig(MaterializationResponsibility &MR,
const Triple &TT,
jitlink::PassConfiguration &Config) {}
virtual void notifyLoaded(MaterializationResponsibility &MR) {}
virtual Error notifyEmitted(MaterializationResponsibility &MR) {
return Error::success();
}
virtual Error notifyRemovingModule(VModuleKey K) {
return Error::success();
}
virtual Error notifyRemovingAllModules() { return Error::success(); }
};
using ReturnObjectBufferFunction =
std::function<void(std::unique_ptr<MemoryBuffer>)>;
/// Construct an ObjectLinkingLayer with the given NotifyLoaded,
/// and NotifyEmitted functors.
ObjectLinkingLayer(ExecutionSession &ES,
jitlink::JITLinkMemoryManager &MemMgr);
/// Destruct an ObjectLinkingLayer.
~ObjectLinkingLayer();
/// Set an object buffer return function. By default object buffers are
/// deleted once the JIT has linked them. If a return function is set then
/// it will be called to transfer ownership of the buffer instead.
void setReturnObjectBuffer(ReturnObjectBufferFunction ReturnObjectBuffer) {
this->ReturnObjectBuffer = std::move(ReturnObjectBuffer);
}
/// Add a pass-config modifier.
ObjectLinkingLayer &addPlugin(std::unique_ptr<Plugin> P) {
std::lock_guard<std::mutex> Lock(LayerMutex);
Plugins.push_back(std::move(P));
return *this;
}
/// Emit the object.
void emit(MaterializationResponsibility R,
std::unique_ptr<MemoryBuffer> O) override;
/// Instructs this ObjectLinkingLayer instance to override the symbol flags
/// found in the AtomGraph with the flags supplied by the
/// MaterializationResponsibility instance. This is a workaround to support
/// symbol visibility in COFF, which does not use the libObject's
/// SF_Exported flag. Use only when generating / adding COFF object files.
///
/// FIXME: We should be able to remove this if/when COFF properly tracks
/// exported symbols.
ObjectLinkingLayer &
setOverrideObjectFlagsWithResponsibilityFlags(bool OverrideObjectFlags) {
this->OverrideObjectFlags = OverrideObjectFlags;
return *this;
}
/// If set, this ObjectLinkingLayer instance will claim responsibility
/// for any symbols provided by a given object file that were not already in
/// the MaterializationResponsibility instance. Setting this flag allows
/// higher-level program representations (e.g. LLVM IR) to be added based on
/// only a subset of the symbols they provide, without having to write
/// intervening layers to scan and add the additional symbols. This trades
/// diagnostic quality for convenience however: If all symbols are enumerated
/// up-front then clashes can be detected and reported early (and usually
/// deterministically). If this option is set, clashes for the additional
/// symbols may not be detected until late, and detection may depend on
/// the flow of control through JIT'd code. Use with care.
ObjectLinkingLayer &
setAutoClaimResponsibilityForObjectSymbols(bool AutoClaimObjectSymbols) {
this->AutoClaimObjectSymbols = AutoClaimObjectSymbols;
return *this;
}
private:
using AllocPtr = std::unique_ptr<jitlink::JITLinkMemoryManager::Allocation>;
void modifyPassConfig(MaterializationResponsibility &MR, const Triple &TT,
jitlink::PassConfiguration &PassConfig);
void notifyLoaded(MaterializationResponsibility &MR);
Error notifyEmitted(MaterializationResponsibility &MR, AllocPtr Alloc);
Error removeModule(VModuleKey K);
Error removeAllModules();
mutable std::mutex LayerMutex;
jitlink::JITLinkMemoryManager &MemMgr;
bool OverrideObjectFlags = false;
bool AutoClaimObjectSymbols = false;
ReturnObjectBufferFunction ReturnObjectBuffer;
DenseMap<VModuleKey, AllocPtr> TrackedAllocs;
std::vector<AllocPtr> UntrackedAllocs;
std::vector<std::unique_ptr<Plugin>> Plugins;
};
class EHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin {
public:
EHFrameRegistrationPlugin(jitlink::EHFrameRegistrar &Registrar);
Error notifyEmitted(MaterializationResponsibility &MR) override;
void modifyPassConfig(MaterializationResponsibility &MR, const Triple &TT,
jitlink::PassConfiguration &PassConfig) override;
Error notifyRemovingModule(VModuleKey K) override;
Error notifyRemovingAllModules() override;
private:
struct EHFrameRange {
JITTargetAddress Addr = 0;
size_t Size;
};
jitlink::EHFrameRegistrar &Registrar;
DenseMap<MaterializationResponsibility *, EHFrameRange> InProcessLinks;
DenseMap<VModuleKey, EHFrameRange> TrackedEHFrameRanges;
std::vector<EHFrameRange> UntrackedEHFrameRanges;
};
} // end namespace orc
} // end namespace llvm
#endif // LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H
|