llvm.org GIT mirror llvm / a817935 include / llvm / ExecutionEngine / Orc / RTDyldObjectLinkingLayer.h

Tree @a817935 (Download .tar.gz)

RTDyldObjectLinkingLayer.h @a817935raw · history · blame

//===- RTDyldObjectLinkingLayer.h - RTDyld-based jit linking  ---*- C++ -*-===//
//                     The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Contains the definition for an RTDyld-based, in-process object linking layer.


#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/RuntimeDyld.h"
#include "llvm/Object/ObjectFile.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 orc {

class RTDyldObjectLinkingLayerBase {

  using ObjectPtr =


  /// @brief Holds a set of objects to be allocated/linked as a unit in the JIT.
  /// An instance of this class will be created for each set of objects added
  /// via JITObjectLayer::addObject. Deleting the instance (via
  /// removeObject) frees its memory, removing all symbol definitions that
  /// had been provided by this instance. Higher level layers are responsible
  /// for taking any action required to handle the missing symbols.
  class LinkedObject {
    LinkedObject() = default;
    LinkedObject(const LinkedObject&) = delete;
    void operator=(const LinkedObject&) = delete;
    virtual ~LinkedObject() = default;

    virtual void finalize() = 0;

    virtual JITSymbol::GetAddressFtor
    getSymbolMaterializer(std::string Name) = 0;

    virtual void mapSectionAddress(const void *LocalAddress,
                                   JITTargetAddress TargetAddr) const = 0;

    JITSymbol getSymbol(StringRef Name, bool ExportedSymbolsOnly) {
      auto SymEntry = SymbolTable.find(Name);
      if (SymEntry == SymbolTable.end())
        return nullptr;
      if (!SymEntry->second.getFlags().isExported() && ExportedSymbolsOnly)
        return nullptr;
      if (!Finalized)
        return JITSymbol(getSymbolMaterializer(Name),
      return JITSymbol(SymEntry->second);

    StringMap<JITEvaluatedSymbol> SymbolTable;
    bool Finalized = false;

  using LinkedObjectListT = std::list<std::unique_ptr<LinkedObject>>;

  /// @brief Handle to a set of loaded objects.
  using ObjHandleT = LinkedObjectListT::iterator;

/// @brief Bare bones object linking layer.
///   This class is intended to be used as the base layer for a JIT. It allows
/// object files to be loaded into memory, linked, and the addresses of their
/// symbols queried. All objects added to this layer can see each other's
/// symbols.
class RTDyldObjectLinkingLayer : public RTDyldObjectLinkingLayerBase {

  using RTDyldObjectLinkingLayerBase::ObjectPtr;

  /// @brief Functor for receiving object-loaded notifications.
  using NotifyLoadedFtor = std::function<void(ObjHandleT, const ObjectPtr &Obj,
                                              const LoadedObjectInfo &)>;

  /// @brief Functor for receiving finalization notifications.
  using NotifyFinalizedFtor = std::function<void(ObjHandleT)>;


  template <typename MemoryManagerPtrT, typename SymbolResolverPtrT,
            typename FinalizerFtor>
  class ConcreteLinkedObject : public LinkedObject {
    ConcreteLinkedObject(ObjectPtr Obj, MemoryManagerPtrT MemMgr,
                         SymbolResolverPtrT Resolver,
                         FinalizerFtor Finalizer,
                         bool ProcessAllSections)
      : MemMgr(std::move(MemMgr)),
                                                   ProcessAllSections)) {

    ~ConcreteLinkedObject() override {

    void setHandle(ObjHandleT H) {
      PFC->Handle = H;

    void finalize() override {
      assert(PFC && "mapSectionAddress called on finalized LinkedObject");

      RuntimeDyld RTDyld(*MemMgr, *PFC->Resolver);
      PFC->RTDyld = &RTDyld;

      this->Finalized = true;
      PFC->Finalizer(PFC->Handle, RTDyld, std::move(PFC->Obj),
                     [&]() {

      // Release resources.
      PFC = nullptr;

    JITSymbol::GetAddressFtor getSymbolMaterializer(std::string Name) override {
        [this, Name]() {
          // The symbol may be materialized between the creation of this lambda
          // and its execution, so we need to double check.
          if (!this->Finalized)
          return this->getSymbol(Name, false).getAddress();

    void mapSectionAddress(const void *LocalAddress,
                           JITTargetAddress TargetAddr) const override {
      assert(PFC && "mapSectionAddress called on finalized LinkedObject");
      assert(PFC->RTDyld && "mapSectionAddress called on raw LinkedObject");
      PFC->RTDyld->mapSectionAddress(LocalAddress, TargetAddr);


    void buildInitialSymbolTable(const ObjectPtr &Obj) {
      for (auto &Symbol : Obj->getBinary()->symbols()) {
        if (Symbol.getFlags() & object::SymbolRef::SF_Undefined)
        Expected<StringRef> SymbolName = Symbol.getName();
        // FIXME: Raise an error for bad symbols.
        if (!SymbolName) {
        auto Flags = JITSymbolFlags::fromObjectSymbol(Symbol);
          std::make_pair(*SymbolName, JITEvaluatedSymbol(0, Flags)));

    void updateSymbolTable(const RuntimeDyld &RTDyld) {
      for (auto &SymEntry : SymbolTable)
        SymEntry.second = RTDyld.getSymbol(SymEntry.first());

    // Contains the information needed prior to finalization: the object files,
    // memory manager, resolver, and flags needed for RuntimeDyld.
    struct PreFinalizeContents {
      PreFinalizeContents(ObjectPtr Obj, SymbolResolverPtrT Resolver,
                          FinalizerFtor Finalizer, bool ProcessAllSections)
        : Obj(std::move(Obj)), Resolver(std::move(Resolver)),
          ProcessAllSections(ProcessAllSections) {}

      ObjectPtr Obj;
      SymbolResolverPtrT Resolver;
      FinalizerFtor Finalizer;
      bool ProcessAllSections;
      ObjHandleT Handle;
      RuntimeDyld *RTDyld;

    MemoryManagerPtrT MemMgr;
    std::unique_ptr<PreFinalizeContents> PFC;

  template <typename MemoryManagerPtrT, typename SymbolResolverPtrT,
            typename FinalizerFtor>
    ConcreteLinkedObject<MemoryManagerPtrT, SymbolResolverPtrT, FinalizerFtor>>
  createLinkedObject(ObjectPtr Obj, MemoryManagerPtrT MemMgr,
                     SymbolResolverPtrT Resolver,
                     FinalizerFtor Finalizer,
                     bool ProcessAllSections) {
    using LOS = ConcreteLinkedObject<MemoryManagerPtrT, SymbolResolverPtrT,
    return llvm::make_unique<LOS>(std::move(Obj), std::move(MemMgr),
                                  std::move(Resolver), std::move(Finalizer),


  /// @brief Functor for creating memory managers.
  using MemoryManagerGetter =

  /// @brief Construct an ObjectLinkingLayer with the given NotifyLoaded,
  ///        and NotifyFinalized functors.
      MemoryManagerGetter GetMemMgr,
      NotifyLoadedFtor NotifyLoaded = NotifyLoadedFtor(),
      NotifyFinalizedFtor NotifyFinalized = NotifyFinalizedFtor())
      : GetMemMgr(GetMemMgr),
        ProcessAllSections(false) {}

  /// @brief Set the 'ProcessAllSections' flag.
  /// If set to true, all sections in each object file will be allocated using
  /// the memory manager, rather than just the sections required for execution.
  /// This is kludgy, and may be removed in the future.
  void setProcessAllSections(bool ProcessAllSections) {
    this->ProcessAllSections = ProcessAllSections;

  /// @brief Add a set of objects (or archives) that will be treated as a unit
  ///        for the purposes of symbol lookup and memory management.
  /// @return A handle that can be used to refer to the loaded objects (for 
  ///         symbol searching, finalization, freeing memory, etc.).
  Expected<ObjHandleT> addObject(ObjectPtr Obj,
                                 std::shared_ptr<JITSymbolResolver> Resolver) {
    auto Finalizer = [&](ObjHandleT H, RuntimeDyld &RTDyld,
                         const ObjectPtr &ObjToLoad,
                         std::function<void()> LOSHandleLoad) {
      std::unique_ptr<RuntimeDyld::LoadedObjectInfo> Info =


      if (this->NotifyLoaded)
        this->NotifyLoaded(H, ObjToLoad, *Info);


      if (this->NotifyFinalized)

    auto LO =
      createLinkedObject(std::move(Obj), GetMemMgr(),
                         std::move(Resolver), std::move(Finalizer),
    // LOS is an owning-ptr. Keep a non-owning one so that we can set the handle
    // below.
    auto *LOPtr = LO.get();

    ObjHandleT Handle = LinkedObjList.insert(LinkedObjList.end(), std::move(LO));

    return Handle;

  /// @brief Remove the set of objects associated with handle H.
  ///   All memory allocated for the objects will be freed, and the sections and
  /// symbols they provided will no longer be available. No attempt is made to
  /// re-emit the missing symbols, and any use of these symbols (directly or
  /// indirectly) will result in undefined behavior. If dependence tracking is
  /// required to detect or resolve such issues it should be added at a higher
  /// layer.
  Error removeObject(ObjHandleT H) {
    // How do we invalidate the symbols in H?
    return Error::success();

  /// @brief Search for the given named symbol.
  /// @param Name The name of the symbol to search for.
  /// @param ExportedSymbolsOnly If true, search only for exported symbols.
  /// @return A handle for the given named symbol, if it exists.
  JITSymbol findSymbol(StringRef Name, bool ExportedSymbolsOnly) {
    for (auto I = LinkedObjList.begin(), E = LinkedObjList.end(); I != E;
      if (auto Symbol = findSymbolIn(I, Name, ExportedSymbolsOnly))
        return Symbol;

    return nullptr;

  /// @brief Search for the given named symbol in the context of the set of
  ///        loaded objects represented by the handle H.
  /// @param H The handle for the object set to search in.
  /// @param Name The name of the symbol to search for.
  /// @param ExportedSymbolsOnly If true, search only for exported symbols.
  /// @return A handle for the given named symbol, if it is found in the
  ///         given object set.
  JITSymbol findSymbolIn(ObjHandleT H, StringRef Name,
                         bool ExportedSymbolsOnly) {
    return (*H)->getSymbol(Name, ExportedSymbolsOnly);

  /// @brief Map section addresses for the objects associated with the handle H.
  void mapSectionAddress(ObjHandleT H, const void *LocalAddress,
                         JITTargetAddress TargetAddr) {
    (*H)->mapSectionAddress(LocalAddress, TargetAddr);

  /// @brief Immediately emit and finalize the object set represented by the
  ///        given handle.
  /// @param H Handle for object set to emit/finalize.
  Error emitAndFinalize(ObjHandleT H) {
    return Error::success();


  LinkedObjectListT LinkedObjList;
  MemoryManagerGetter GetMemMgr;
  NotifyLoadedFtor NotifyLoaded;
  NotifyFinalizedFtor NotifyFinalized;
  bool ProcessAllSections = false;

} // end namespace orc
} // end namespace llvm