9931f95bac
The following are the most significant peculiarities of MIPS target: - MIPS ABI requires some special tags in the dynamic table. - GOT consists of two parts local and global. The local part contains entries refer locally visible symbols. The global part contains entries refer global symbols. - Entries in the .dynsym section which have corresponded entries in the GOT should be: * Emitted at the end of .dynsym section * Sorted accordingly to theirs GOT counterparts - There are "paired" relocations. One or more R_MIPS_HI16 and R_MIPS_GOT16 relocations should be followed by R_MIPS_LO16 relocation. To calculate result of R_MIPS_HI16 and R_MIPS_GOT16 relocations we need to combine addends from these relocations and paired R_MIPS_LO16 relocation. The patch reviewed by Michael Spencer, Shankar Easwaran, Rui Ueyama. http://llvm-reviews.chandlerc.com/D2156 llvm-svn: 197342
137 lines
4.1 KiB
C++
137 lines
4.1 KiB
C++
//===- lib/ReaderWriter/ELF/TargetHandler.h -------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief These interfaces provide target specific hooks to change the linker's
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/// behaivor.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLD_READER_WRITER_ELF_TARGET_HANDLER_H
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#define LLD_READER_WRITER_ELF_TARGET_HANDLER_H
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#include "Layout.h"
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#include "lld/Core/LLVM.h"
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#include "lld/Core/LinkingContext.h"
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#include "lld/Core/STDExtras.h"
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#include "lld/ReaderWriter/ELFLinkingContext.h"
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#include "llvm/ADT/Hashing.h"
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#include "llvm/Support/FileOutputBuffer.h"
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#include <memory>
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#include <vector>
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namespace lld {
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namespace elf {
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template <class ELFT> class DynamicTable;
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template <class ELFT> class DynamicSymbolTable;
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template <class ELFT> class ELFDefinedAtom;
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template <class ELFT> class ELFReference;
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class ELFWriter;
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template <class ELFT> class ELFHeader;
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template <class ELFT> class Section;
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template <class ELFT> class TargetLayout;
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/// \brief The target registers a set of handlers for overriding target specific
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/// attributes for a DefinedAtom. The Reader uses this class to query for the
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/// type of atom and its permissions
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template <class ELFT> class TargetAtomHandler {
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public:
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typedef llvm::object::Elf_Shdr_Impl<ELFT> Elf_Shdr;
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typedef llvm::object::Elf_Sym_Impl<ELFT> Elf_Sym;
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virtual DefinedAtom::ContentType
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contentType(const ELFDefinedAtom<ELFT> *atom) const {
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return atom->contentType();
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}
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virtual DefinedAtom::ContentType
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contentType(const Elf_Shdr *shdr, const Elf_Sym *sym) const {
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return DefinedAtom::typeZeroFill;
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}
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virtual DefinedAtom::ContentPermissions
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contentPermissions(const ELFDefinedAtom<ELFT> *atom) const {
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return atom->permissions();
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}
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virtual int64_t getType(const Elf_Sym *sym) const {
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return llvm::ELF::STT_NOTYPE;
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}
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virtual ~TargetAtomHandler() {}
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};
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template <class ELFT> class TargetRelocationHandler {
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public:
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virtual error_code
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applyRelocation(ELFWriter &, llvm::FileOutputBuffer &,
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const lld::AtomLayout &, const Reference &) const = 0;
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virtual int64_t relocAddend(const Reference &)const { return 0; }
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virtual ~TargetRelocationHandler() {}
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};
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/// \brief An interface to override functions that are provided by the
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/// the default ELF Layout
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template <class ELFT> class TargetHandler : public TargetHandlerBase {
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public:
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TargetHandler(ELFLinkingContext &targetInfo) : _context(targetInfo) {}
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/// If the target overrides ELF header information, this API would
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/// return true, so that the target can set all fields specific to
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/// that target
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virtual bool doesOverrideELFHeader() = 0;
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/// Set the ELF Header information
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virtual void setELFHeader(ELFHeader<ELFT> *elfHeader) = 0;
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/// TargetLayout
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virtual TargetLayout<ELFT> &targetLayout() = 0;
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/// TargetAtomHandler
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virtual TargetAtomHandler<ELFT> &targetAtomHandler() = 0;
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virtual const TargetRelocationHandler<ELFT> &getRelocationHandler() const = 0;
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/// Create a set of Default target sections that a target might needj
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virtual void createDefaultSections() = 0;
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/// \brief Add a section to the current Layout
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virtual void addSection(Section<ELFT> *section) = 0;
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/// \brief add new symbol file
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virtual bool createImplicitFiles(std::vector<std::unique_ptr<File> > &) = 0;
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/// \brief Finalize the symbol values
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virtual void finalizeSymbolValues() = 0;
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/// \brief allocate Commons, some architectures may move small common
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/// symbols over to small data, this would also be used
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virtual void allocateCommons() = 0;
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/// \brief create dynamic table
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virtual LLD_UNIQUE_BUMP_PTR(DynamicTable<ELFT>) createDynamicTable() = 0;
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/// \brief create dynamic symbol table
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virtual LLD_UNIQUE_BUMP_PTR(DynamicSymbolTable<ELFT>)
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createDynamicSymbolTable() = 0;
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protected:
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ELFLinkingContext &_context;
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};
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} // end namespace elf
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} // end namespace lld
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#endif
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