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//===-- ELFNixPlatform.h -- Utilities for executing ELF in Orc --*- 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
//
//===----------------------------------------------------------------------===//
//
// Linux/BSD support for executing JIT'd ELF in Orc.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H
#define LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H
#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"
#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
#include "llvm/ExecutionEngine/Orc/Shared/ExecutorAddress.h"
#include <future>
#include <thread>
#include <vector>
namespace llvm {
namespace orc {
struct ELFPerObjectSectionsToRegister {
ExecutorAddrRange EHFrameSection;
ExecutorAddrRange ThreadDataSection;
};
struct ELFNixJITDylibInitializers {
using SectionList = std::vector<ExecutorAddrRange>;
ELFNixJITDylibInitializers(std::string Name, ExecutorAddr DSOHandleAddress)
: Name(std::move(Name)), DSOHandleAddress(std::move(DSOHandleAddress)) {}
std::string Name;
ExecutorAddr DSOHandleAddress;
StringMap<SectionList> InitSections;
};
class ELFNixJITDylibDeinitializers {};
using ELFNixJITDylibInitializerSequence =
std::vector<ELFNixJITDylibInitializers>;
using ELFNixJITDylibDeinitializerSequence =
std::vector<ELFNixJITDylibDeinitializers>;
/// Mediates between ELFNix initialization and ExecutionSession state.
class ELFNixPlatform : public Platform {
public:
/// Try to create a ELFNixPlatform instance, adding the ORC runtime to the
/// given JITDylib.
///
/// The ORC runtime requires access to a number of symbols in
/// libc++. It is up to the caller to ensure that the required
/// symbols can be referenced by code added to PlatformJD. The
/// standard way to achieve this is to first attach dynamic library
/// search generators for either the given process, or for the
/// specific required libraries, to PlatformJD, then to create the
/// platform instance:
///
/// \code{.cpp}
/// auto &PlatformJD = ES.createBareJITDylib("stdlib");
/// PlatformJD.addGenerator(
/// ExitOnErr(EPCDynamicLibrarySearchGenerator
/// ::GetForTargetProcess(EPC)));
/// ES.setPlatform(
/// ExitOnErr(ELFNixPlatform::Create(ES, ObjLayer, EPC, PlatformJD,
/// "/path/to/orc/runtime")));
/// \endcode
///
/// Alternatively, these symbols could be added to another JITDylib that
/// PlatformJD links against.
///
/// Clients are also responsible for ensuring that any JIT'd code that
/// depends on runtime functions (including any code using TLV or static
/// destructors) can reference the runtime symbols. This is usually achieved
/// by linking any JITDylibs containing regular code against
/// PlatformJD.
///
/// By default, ELFNixPlatform will add the set of aliases returned by the
/// standardPlatformAliases function. This includes both required aliases
/// (e.g. __cxa_atexit -> __orc_rt_elf_cxa_atexit for static destructor
/// support), and optional aliases that provide JIT versions of common
/// functions (e.g. dlopen -> __orc_rt_elf_jit_dlopen). Clients can
/// override these defaults by passing a non-None value for the
/// RuntimeAliases function, in which case the client is responsible for
/// setting up all aliases (including the required ones).
static Expected<std::unique_ptr<ELFNixPlatform>>
Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
JITDylib &PlatformJD, std::unique_ptr<DefinitionGenerator> OrcRuntime,
std::optional<SymbolAliasMap> RuntimeAliases = std::nullopt);
/// Construct using a path to the ORC runtime.
static Expected<std::unique_ptr<ELFNixPlatform>>
Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
JITDylib &PlatformJD, const char *OrcRuntimePath,
std::optional<SymbolAliasMap> RuntimeAliases = std::nullopt);
ExecutionSession &getExecutionSession() const { return ES; }
ObjectLinkingLayer &getObjectLinkingLayer() const { return ObjLinkingLayer; }
Error setupJITDylib(JITDylib &JD) override;
Error teardownJITDylib(JITDylib &JD) override;
Error notifyAdding(ResourceTracker &RT,
const MaterializationUnit &MU) override;
Error notifyRemoving(ResourceTracker &RT) override;
/// Returns an AliasMap containing the default aliases for the ELFNixPlatform.
/// This can be modified by clients when constructing the platform to add
/// or remove aliases.
static Expected<SymbolAliasMap> standardPlatformAliases(ExecutionSession &ES,
JITDylib &PlatformJD);
/// Returns the array of required CXX aliases.
static ArrayRef<std::pair<const char *, const char *>> requiredCXXAliases();
/// Returns the array of standard runtime utility aliases for ELF.
static ArrayRef<std::pair<const char *, const char *>>
standardRuntimeUtilityAliases();
private:
// The ELFNixPlatformPlugin scans/modifies LinkGraphs to support ELF
// platform features including initializers, exceptions, TLV, and language
// runtime registration.
class ELFNixPlatformPlugin : public ObjectLinkingLayer::Plugin {
public:
ELFNixPlatformPlugin(ELFNixPlatform &MP) : MP(MP) {}
void modifyPassConfig(MaterializationResponsibility &MR,
jitlink::LinkGraph &G,
jitlink::PassConfiguration &Config) override;
SyntheticSymbolDependenciesMap
getSyntheticSymbolDependencies(MaterializationResponsibility &MR) override;
// FIXME: We should be tentatively tracking scraped sections and discarding
// if the MR fails.
Error notifyFailed(MaterializationResponsibility &MR) override {
return Error::success();
}
Error notifyRemovingResources(JITDylib &JD, ResourceKey K) override {
return Error::success();
}
void notifyTransferringResources(JITDylib &JD, ResourceKey DstKey,
ResourceKey SrcKey) override {}
private:
using InitSymbolDepMap =
DenseMap<MaterializationResponsibility *, JITLinkSymbolSet>;
void addInitializerSupportPasses(MaterializationResponsibility &MR,
jitlink::PassConfiguration &Config);
void addDSOHandleSupportPasses(MaterializationResponsibility &MR,
jitlink::PassConfiguration &Config);
void addEHAndTLVSupportPasses(MaterializationResponsibility &MR,
jitlink::PassConfiguration &Config);
Error preserveInitSections(jitlink::LinkGraph &G,
MaterializationResponsibility &MR);
Error registerInitSections(jitlink::LinkGraph &G, JITDylib &JD);
Error fixTLVSectionsAndEdges(jitlink::LinkGraph &G, JITDylib &JD);
std::mutex PluginMutex;
ELFNixPlatform &MP;
InitSymbolDepMap InitSymbolDeps;
};
using SendInitializerSequenceFn =
unique_function<void(Expected<ELFNixJITDylibInitializerSequence>)>;
using SendDeinitializerSequenceFn =
unique_function<void(Expected<ELFNixJITDylibDeinitializerSequence>)>;
using SendSymbolAddressFn = unique_function<void(Expected<ExecutorAddr>)>;
static bool supportedTarget(const Triple &TT);
ELFNixPlatform(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
JITDylib &PlatformJD,
std::unique_ptr<DefinitionGenerator> OrcRuntimeGenerator,
Error &Err);
// Associate ELFNixPlatform JIT-side runtime support functions with handlers.
Error associateRuntimeSupportFunctions(JITDylib &PlatformJD);
void getInitializersBuildSequencePhase(SendInitializerSequenceFn SendResult,
JITDylib &JD,
std::vector<JITDylibSP> DFSLinkOrder);
void getInitializersLookupPhase(SendInitializerSequenceFn SendResult,
JITDylib &JD);
void rt_getInitializers(SendInitializerSequenceFn SendResult,
StringRef JDName);
void rt_getDeinitializers(SendDeinitializerSequenceFn SendResult,
ExecutorAddr Handle);
void rt_lookupSymbol(SendSymbolAddressFn SendResult, ExecutorAddr Handle,
StringRef SymbolName);
// Records the addresses of runtime symbols used by the platform.
Error bootstrapELFNixRuntime(JITDylib &PlatformJD);
Error registerInitInfo(JITDylib &JD,
ArrayRef<jitlink::Section *> InitSections);
Error registerPerObjectSections(const ELFPerObjectSectionsToRegister &POSR);
Expected<uint64_t> createPThreadKey();
ExecutionSession &ES;
ObjectLinkingLayer &ObjLinkingLayer;
SymbolStringPtr DSOHandleSymbol;
std::atomic<bool> RuntimeBootstrapped{false};
ExecutorAddr orc_rt_elfnix_platform_bootstrap;
ExecutorAddr orc_rt_elfnix_platform_shutdown;
ExecutorAddr orc_rt_elfnix_register_object_sections;
ExecutorAddr orc_rt_elfnix_create_pthread_key;
DenseMap<JITDylib *, SymbolLookupSet> RegisteredInitSymbols;
// InitSeqs gets its own mutex to avoid locking the whole session when
// aggregating data from the jitlink.
std::mutex PlatformMutex;
DenseMap<JITDylib *, ELFNixJITDylibInitializers> InitSeqs;
std::vector<ELFPerObjectSectionsToRegister> BootstrapPOSRs;
DenseMap<ExecutorAddr, JITDylib *> HandleAddrToJITDylib;
DenseMap<JITDylib *, uint64_t> JITDylibToPThreadKey;
};
namespace shared {
using SPSELFPerObjectSectionsToRegister =
SPSTuple<SPSExecutorAddrRange, SPSExecutorAddrRange>;
template <>
class SPSSerializationTraits<SPSELFPerObjectSectionsToRegister,
ELFPerObjectSectionsToRegister> {
public:
static size_t size(const ELFPerObjectSectionsToRegister &MOPOSR) {
return SPSELFPerObjectSectionsToRegister::AsArgList::size(
MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection);
}
static bool serialize(SPSOutputBuffer &OB,
const ELFPerObjectSectionsToRegister &MOPOSR) {
return SPSELFPerObjectSectionsToRegister::AsArgList::serialize(
OB, MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection);
}
static bool deserialize(SPSInputBuffer &IB,
ELFPerObjectSectionsToRegister &MOPOSR) {
return SPSELFPerObjectSectionsToRegister::AsArgList::deserialize(
IB, MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection);
}
};
using SPSNamedExecutorAddrRangeSequenceMap =
SPSSequence<SPSTuple<SPSString, SPSExecutorAddrRangeSequence>>;
using SPSELFNixJITDylibInitializers =
SPSTuple<SPSString, SPSExecutorAddr, SPSNamedExecutorAddrRangeSequenceMap>;
using SPSELFNixJITDylibInitializerSequence =
SPSSequence<SPSELFNixJITDylibInitializers>;
/// Serialization traits for ELFNixJITDylibInitializers.
template <>
class SPSSerializationTraits<SPSELFNixJITDylibInitializers,
ELFNixJITDylibInitializers> {
public:
static size_t size(const ELFNixJITDylibInitializers &MOJDIs) {
return SPSELFNixJITDylibInitializers::AsArgList::size(
MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections);
}
static bool serialize(SPSOutputBuffer &OB,
const ELFNixJITDylibInitializers &MOJDIs) {
return SPSELFNixJITDylibInitializers::AsArgList::serialize(
OB, MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections);
}
static bool deserialize(SPSInputBuffer &IB,
ELFNixJITDylibInitializers &MOJDIs) {
return SPSELFNixJITDylibInitializers::AsArgList::deserialize(
IB, MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections);
}
};
using SPSELFJITDylibDeinitializers = SPSEmpty;
using SPSELFJITDylibDeinitializerSequence =
SPSSequence<SPSELFJITDylibDeinitializers>;
template <>
class SPSSerializationTraits<SPSELFJITDylibDeinitializers,
ELFNixJITDylibDeinitializers> {
public:
static size_t size(const ELFNixJITDylibDeinitializers &MOJDDs) { return 0; }
static bool serialize(SPSOutputBuffer &OB,
const ELFNixJITDylibDeinitializers &MOJDDs) {
return true;
}
static bool deserialize(SPSInputBuffer &IB,
ELFNixJITDylibDeinitializers &MOJDDs) {
MOJDDs = ELFNixJITDylibDeinitializers();
return true;
}
};
} // end namespace shared
} // end namespace orc
} // end namespace llvm
#endif // LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H
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