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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/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 <utility>
#include <vector>
namespace llvm {
namespace jitlink {
class EHFrameRegistrar;
class LinkGraph;
class Symbol;
} // namespace jitlink
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 RTTIExtends<ObjectLinkingLayer, ObjectLayer>,
private ResourceManager {
friend class ObjectLinkingLayerJITLinkContext;
public:
static char ID;
/// 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:
using JITLinkSymbolSet = DenseSet<jitlink::Symbol *>;
using SyntheticSymbolDependenciesMap =
DenseMap<SymbolStringPtr, JITLinkSymbolSet>;
virtual ~Plugin();
virtual void modifyPassConfig(MaterializationResponsibility &MR,
jitlink::LinkGraph &G,
jitlink::PassConfiguration &Config) {}
// Deprecated. Don't use this in new code. There will be a proper mechanism
// for capturing object buffers.
virtual void notifyMaterializing(MaterializationResponsibility &MR,
jitlink::LinkGraph &G,
jitlink::JITLinkContext &Ctx,
MemoryBufferRef InputObject) {}
virtual void notifyLoaded(MaterializationResponsibility &MR) {}
virtual Error notifyEmitted(MaterializationResponsibility &MR) {
return Error::success();
}
virtual Error notifyFailed(MaterializationResponsibility &MR) = 0;
virtual Error notifyRemovingResources(JITDylib &JD, ResourceKey K) = 0;
virtual void notifyTransferringResources(JITDylib &JD, ResourceKey DstKey,
ResourceKey SrcKey) = 0;
/// Return any dependencies that synthetic symbols (e.g. init symbols)
/// have on symbols in the LinkGraph.
/// This is used by the ObjectLinkingLayer to update the dependencies for
/// the synthetic symbols.
virtual SyntheticSymbolDependenciesMap
getSyntheticSymbolDependencies(MaterializationResponsibility &MR) {
return SyntheticSymbolDependenciesMap();
}
};
using ReturnObjectBufferFunction =
std::function<void(std::unique_ptr<MemoryBuffer>)>;
/// Construct an ObjectLinkingLayer using the ExecutorProcessControl
/// instance's memory manager.
ObjectLinkingLayer(ExecutionSession &ES);
/// Construct an ObjectLinkingLayer using a custom memory manager.
ObjectLinkingLayer(ExecutionSession &ES,
jitlink::JITLinkMemoryManager &MemMgr);
/// Construct an ObjectLinkingLayer. Takes ownership of the given
/// JITLinkMemoryManager. This method is a temporary hack to simplify
/// co-existence with RTDyldObjectLinkingLayer (which also owns its
/// allocators).
ObjectLinkingLayer(ExecutionSession &ES,
std::unique_ptr<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 plugin.
ObjectLinkingLayer &addPlugin(std::shared_ptr<Plugin> P) {
std::lock_guard<std::mutex> Lock(LayerMutex);
Plugins.push_back(std::move(P));
return *this;
}
/// Remove a plugin. This remove applies only to subsequent links (links
/// already underway will continue to use the plugin), and does not of itself
/// destroy the plugin -- destruction will happen once all shared pointers
/// (including those held by in-progress links) are destroyed.
void removePlugin(Plugin &P) {
std::lock_guard<std::mutex> Lock(LayerMutex);
auto I = llvm::find_if(Plugins, [&](const std::shared_ptr<Plugin> &Elem) {
return Elem.get() == &P;
});
assert(I != Plugins.end() && "Plugin not present");
Plugins.erase(I);
}
/// Add a LinkGraph to the JITDylib targeted by the given tracker.
Error add(ResourceTrackerSP, std::unique_ptr<jitlink::LinkGraph> G);
/// Add a LinkGraph to the given JITDylib.
Error add(JITDylib &JD, std::unique_ptr<jitlink::LinkGraph> G) {
return add(JD.getDefaultResourceTracker(), std::move(G));
}
// Un-hide ObjectLayer add methods.
using ObjectLayer::add;
/// Emit an object file.
void emit(std::unique_ptr<MaterializationResponsibility> R,
std::unique_ptr<MemoryBuffer> O) override;
/// Emit a LinkGraph.
void emit(std::unique_ptr<MaterializationResponsibility> R,
std::unique_ptr<jitlink::LinkGraph> G);
/// 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 FinalizedAlloc = jitlink::JITLinkMemoryManager::FinalizedAlloc;
Error recordFinalizedAlloc(MaterializationResponsibility &MR,
FinalizedAlloc FA);
Error handleRemoveResources(JITDylib &JD, ResourceKey K) override;
void handleTransferResources(JITDylib &JD, ResourceKey DstKey,
ResourceKey SrcKey) override;
mutable std::mutex LayerMutex;
jitlink::JITLinkMemoryManager &MemMgr;
std::unique_ptr<jitlink::JITLinkMemoryManager> MemMgrOwnership;
bool OverrideObjectFlags = false;
bool AutoClaimObjectSymbols = false;
ReturnObjectBufferFunction ReturnObjectBuffer;
DenseMap<ResourceKey, std::vector<FinalizedAlloc>> Allocs;
std::vector<std::shared_ptr<Plugin>> Plugins;
};
class EHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin {
public:
EHFrameRegistrationPlugin(
ExecutionSession &ES,
std::unique_ptr<jitlink::EHFrameRegistrar> Registrar);
void modifyPassConfig(MaterializationResponsibility &MR,
jitlink::LinkGraph &G,
jitlink::PassConfiguration &PassConfig) override;
Error notifyEmitted(MaterializationResponsibility &MR) override;
Error notifyFailed(MaterializationResponsibility &MR) override;
Error notifyRemovingResources(JITDylib &JD, ResourceKey K) override;
void notifyTransferringResources(JITDylib &JD, ResourceKey DstKey,
ResourceKey SrcKey) override;
private:
std::mutex EHFramePluginMutex;
ExecutionSession &ES;
std::unique_ptr<jitlink::EHFrameRegistrar> Registrar;
DenseMap<MaterializationResponsibility *, ExecutorAddrRange> InProcessLinks;
DenseMap<ResourceKey, std::vector<ExecutorAddrRange>> EHFrameRanges;
};
} // end namespace orc
} // end namespace llvm
#endif // LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H
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