llvm-project/lld/lib/ReaderWriter/ELF/TargetHandler.h

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//===- lib/ReaderWriter/ELF/TargetHandler.h -------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief These interfaces provide target specific hooks to change the linker's
/// behaivor.
///
//===----------------------------------------------------------------------===//
#ifndef LLD_READER_WRITER_ELF_TARGET_HANDLER_H
#define LLD_READER_WRITER_ELF_TARGET_HANDLER_H
#include "Layout.h"
#include "lld/Core/InputFiles.h"
#include "lld/Core/LLVM.h"
#include "lld/Core/TargetInfo.h"
#include "lld/ReaderWriter/ELFTargetInfo.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/Support/FileOutputBuffer.h"
#include <memory>
#include <vector>
namespace lld {
namespace elf {
template <class ELFT> class ELFDefinedAtom;
template <class ELFT> class ELFReference;
class ELFWriter;
template <class ELFT> class Header;
template <class ELFT> class Section;
template <class ELFT> class TargetLayout;
/// \brief The target registers a set of handlers for overriding target specific
/// attributes for a DefinedAtom. The Reader uses this class to query for the
/// type of atom and its permissions
template <class ELFT> class TargetAtomHandler {
public:
typedef llvm::object::Elf_Shdr_Impl<ELFT> Elf_Shdr;
typedef llvm::object::Elf_Sym_Impl<ELFT> Elf_Sym;
virtual DefinedAtom::ContentType
contentType(const ELFDefinedAtom<ELFT> *atom) const {
return atom->contentType();
}
virtual DefinedAtom::ContentType
contentType(const Elf_Shdr *shdr, const Elf_Sym *sym) const {
return DefinedAtom::typeZeroFill;
}
virtual DefinedAtom::ContentPermissions
contentPermissions(const ELFDefinedAtom<ELFT> *atom) const {
return atom->permissions();
}
virtual int64_t getType(const Elf_Sym *sym) const {
return llvm::ELF::STT_NOTYPE;
}
virtual ~TargetAtomHandler() {}
};
template <class ELFT> class TargetRelocationHandler {
public:
virtual ErrorOr<void>
applyRelocation(ELFWriter &, llvm::FileOutputBuffer &,
const lld::AtomLayout &, const Reference &) const = 0;
virtual int64_t relocAddend(const Reference &)const { return 0; }
virtual ~TargetRelocationHandler() {}
};
/// \brief An interface to override functions that are provided by the
/// the default ELF Layout
template <class ELFT> class TargetHandler : public TargetHandlerBase {
public:
TargetHandler(ELFTargetInfo &targetInfo) : _targetInfo(targetInfo) {}
/// If the target overrides ELF header information, this API would
/// return true, so that the target can set all fields specific to
/// that target
virtual bool doesOverrideHeader() = 0;
/// Set the ELF Header information
virtual void setHeaderInfo(Header<ELFT> *Header) = 0;
/// TargetLayout
virtual TargetLayout<ELFT> &targetLayout() = 0;
/// TargetAtomHandler
virtual TargetAtomHandler<ELFT> &targetAtomHandler() = 0;
virtual const TargetRelocationHandler<ELFT> &getRelocationHandler() const = 0;
/// Create a set of Default target sections that a target might needj
virtual void createDefaultSections() = 0;
/// \brief Add a section to the current Layout
virtual void addSection(Section<ELFT> *section) = 0;
/// \brief add new symbol file
virtual void addFiles(InputFiles &) = 0;
/// \brief Finalize the symbol values
virtual void finalizeSymbolValues() = 0;
/// \brief allocate Commons, some architectures may move small common
/// symbols over to small data, this would also be used
virtual void allocateCommons() = 0;
protected:
const ELFTargetInfo &_targetInfo;
};
} // end namespace elf
} // end namespace lld
#endif