text: //===- ObjectTransformLayer.h - Run all objects through functor -*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // Run all objects passed in through a user supplied functor.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_EXECUTIONENGINE_ORC_OBJECTTRANSFORMLAYER_H
  #define LLVM_EXECUTIONENGINE_ORC_OBJECTTRANSFORMLAYER_H
  
  #include "llvm/ExecutionEngine/JITSymbol.h"
  #include "llvm/ExecutionEngine/Orc/Layer.h"
  #include <algorithm>
  #include <memory>
  #include <string>
  
  namespace llvm {
  namespace orc {
  
  class ObjectTransformLayer : public ObjectLayer {
  public:
    using TransformFunction =
        std::function<Expected<std::unique_ptr<MemoryBuffer>>(
            std::unique_ptr<MemoryBuffer>)>;
  
    ObjectTransformLayer(ExecutionSession &ES, ObjectLayer &BaseLayer,
                         TransformFunction Transform);
  
    void emit(MaterializationResponsibility R,
              std::unique_ptr<MemoryBuffer> O) override;
  
  private:
    ObjectLayer &BaseLayer;
    TransformFunction Transform;
  };
  
  /// Object mutating layer.
  ///
  ///   This layer accepts sets of ObjectFiles (via addObject). It
  /// immediately applies the user supplied functor to each object, then adds
  /// the set of transformed objects to the layer below.
  template <typename BaseLayerT, typename TransformFtor>
  class LegacyObjectTransformLayer {
  public:
    /// Construct an ObjectTransformLayer with the given BaseLayer
    LegacyObjectTransformLayer(BaseLayerT &BaseLayer,
                               TransformFtor Transform = TransformFtor())
        : BaseLayer(BaseLayer), Transform(std::move(Transform)) {}
  
    /// Apply the transform functor to each object in the object set, then
    ///        add the resulting set of objects to the base layer, along with the
    ///        memory manager and symbol resolver.
    ///
    /// @return A handle for the added objects.
    template <typename ObjectPtr> Error addObject(VModuleKey K, ObjectPtr Obj) {
      return BaseLayer.addObject(std::move(K), Transform(std::move(Obj)));
    }
  
    /// Remove the object set associated with the VModuleKey K.
    Error removeObject(VModuleKey K) { return BaseLayer.removeObject(K); }
  
    /// 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(const std::string &Name, bool ExportedSymbolsOnly) {
      return BaseLayer.findSymbol(Name, ExportedSymbolsOnly);
    }
  
    /// Get the address of the given symbol in the context of the set of
    ///        objects represented by the VModuleKey K. This call is forwarded to
    ///        the base layer's implementation.
    /// @param K The VModuleKey associated with 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(VModuleKey K, const std::string &Name,
                           bool ExportedSymbolsOnly) {
      return BaseLayer.findSymbolIn(K, Name, ExportedSymbolsOnly);
    }
  
    /// Immediately emit and finalize the object set represented by the
    ///        given VModuleKey K.
    Error emitAndFinalize(VModuleKey K) { return BaseLayer.emitAndFinalize(K); }
  
    /// Map section addresses for the objects associated with the
    /// VModuleKey K.
    void mapSectionAddress(VModuleKey K, const void *LocalAddress,
                           JITTargetAddress TargetAddr) {
      BaseLayer.mapSectionAddress(K, LocalAddress, TargetAddr);
    }
  
    /// Access the transform functor directly.
    TransformFtor &getTransform() { return Transform; }
  
    /// Access the mumate functor directly.
    const TransformFtor &getTransform() const { return Transform; }
  
  private:
    BaseLayerT &BaseLayer;
    TransformFtor Transform;
  };
  
  } // end namespace orc
  } // end namespace llvm
  
  #endif // LLVM_EXECUTIONENGINE_ORC_OBJECTTRANSFORMLAYER_H
  