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//===- lib/FileFormat/MachO/ArchHandler.h ---------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MachONormalizedFile.h"
#include "lld/Core/LLVM.h"
#include "lld/Core/Reference.h"
#include "lld/Core/Simple.h"
#include "lld/ReaderWriter/MachOLinkingContext.h"
#include "llvm/ADT/Triple.h"
#ifndef LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
#define LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
namespace lld {
namespace mach_o {
///
/// The ArchHandler class handles all architecture specific aspects of
/// mach-o linking.
///
class ArchHandler {
public:
virtual ~ArchHandler();
/// There is no public interface to subclasses of ArchHandler, so this
/// is the only way to instantiate an ArchHandler.
static std::unique_ptr<ArchHandler> create(MachOLinkingContext::Arch arch);
/// Get (arch specific) kind strings used by Registry.
virtual const Registry::KindStrings *kindStrings() = 0;
/// Convert mach-o Arch to Reference::KindArch.
virtual Reference::KindArch kindArch() = 0;
/// Used by StubPass to update References to shared library functions
/// to be references to a stub.
virtual bool isCallSite(const Reference &) = 0;
/// Used by GOTPass to locate GOT References
virtual bool isGOTAccess(const Reference &, bool &canBypassGOT) {
return false;
}
/// Used by GOTPass to update GOT References
virtual void updateReferenceToGOT(const Reference *, bool targetIsNowGOT) {}
/// Used by normalizedFromAtoms() to know where to generated rebasing and
/// binding info in final executables.
virtual bool isPointer(const Reference &) = 0;
/// Used by normalizedFromAtoms() to know where to generated lazy binding
/// info in final executables.
virtual bool isLazyPointer(const Reference &);
/// Returns true if the specified relocation is paired to the next relocation.
virtual bool isPairedReloc(const normalized::Relocation &) = 0;
/// Prototype for a helper function. Given a sectionIndex and address,
/// finds the atom and offset with that atom of that address.
typedef std::function<std::error_code (uint32_t sectionIndex, uint64_t addr,
const lld::Atom **, Reference::Addend *)>
FindAtomBySectionAndAddress;
/// Prototype for a helper function. Given a symbolIndex, finds the atom
/// representing that symbol.
typedef std::function<std::error_code (uint32_t symbolIndex,
const lld::Atom **)> FindAtomBySymbolIndex;
/// Analyzes a relocation from a .o file and returns the info
/// (kind, target, addend) needed to instantiate a Reference.
/// Two helper functions are passed as parameters to find the target atom
/// given a symbol index or address.
virtual std::error_code
getReferenceInfo(const normalized::Relocation &reloc,
const DefinedAtom *inAtom,
uint32_t offsetInAtom,
uint64_t fixupAddress, bool swap,
FindAtomBySectionAndAddress atomFromAddress,
FindAtomBySymbolIndex atomFromSymbolIndex,
Reference::KindValue *kind,
const lld::Atom **target,
Reference::Addend *addend) = 0;
/// Analyzes a pair of relocations from a .o file and returns the info
/// (kind, target, addend) needed to instantiate a Reference.
/// Two helper functions are passed as parameters to find the target atom
/// given a symbol index or address.
virtual std::error_code
getPairReferenceInfo(const normalized::Relocation &reloc1,
const normalized::Relocation &reloc2,
const DefinedAtom *inAtom,
uint32_t offsetInAtom,
uint64_t fixupAddress, bool swap,
FindAtomBySectionAndAddress atomFromAddress,
FindAtomBySymbolIndex atomFromSymbolIndex,
Reference::KindValue *kind,
const lld::Atom **target,
Reference::Addend *addend) = 0;
/// Prototype for a helper function. Given an atom, finds the symbol table
/// index for it in the output file.
typedef std::function<uint32_t (const Atom &atom)> FindSymbolIndexForAtom;
/// Prototype for a helper function. Given an atom, finds the index
/// of the section that will contain the atom.
typedef std::function<uint32_t (const Atom &atom)> FindSectionIndexForAtom;
/// Prototype for a helper function. Given an atom, finds the address
/// assigned to it in the output file.
typedef std::function<uint64_t (const Atom &atom)> FindAddressForAtom;
/// Some architectures require local symbols on anonymous atoms.
virtual bool needsLocalSymbolInRelocatableFile(const DefinedAtom *atom) {
return false;
}
/// Copy raw content then apply all fixup References on an Atom.
virtual void generateAtomContent(const DefinedAtom &atom, bool relocatable,
FindAddressForAtom findAddress,
uint8_t *atomContentBuffer) = 0;
/// Used in -r mode to convert a Reference to a mach-o relocation.
virtual void appendSectionRelocations(const DefinedAtom &atom,
uint64_t atomSectionOffset,
const Reference &ref,
FindSymbolIndexForAtom,
FindSectionIndexForAtom,
FindAddressForAtom,
normalized::Relocations&) = 0;
struct ReferenceInfo {
Reference::KindArch arch;
uint16_t kind;
uint32_t offset;
int32_t addend;
};
/// Table of architecture specific information for creating stubs.
struct StubInfo {
const char* binderSymbolName;
ReferenceInfo lazyPointerReferenceToHelper;
ReferenceInfo lazyPointerReferenceToFinal;
ReferenceInfo nonLazyPointerReferenceToBinder;
uint8_t codeAlignment;
uint32_t stubSize;
uint8_t stubBytes[16];
ReferenceInfo stubReferenceToLP;
uint32_t stubHelperSize;
uint8_t stubHelperBytes[16];
ReferenceInfo stubHelperReferenceToImm;
ReferenceInfo stubHelperReferenceToHelperCommon;
uint32_t stubHelperCommonSize;
uint8_t stubHelperCommonBytes[36];
ReferenceInfo stubHelperCommonReferenceToCache;
ReferenceInfo stubHelperCommonReferenceToBinder;
};
virtual const StubInfo &stubInfo() = 0;
protected:
ArchHandler();
static std::unique_ptr<mach_o::ArchHandler> create_x86_64();
static std::unique_ptr<mach_o::ArchHandler> create_x86();
static std::unique_ptr<mach_o::ArchHandler> create_arm();
// Handy way to pack mach-o r_type and other bit fields into one 16-bit value.
typedef uint16_t RelocPattern;
enum {
rScattered = 0x8000,
rPcRel = 0x4000,
rExtern = 0x2000,
rLength1 = 0x0000,
rLength2 = 0x0100,
rLength4 = 0x0200,
rLength8 = 0x0300,
rLenArmLo = rLength1,
rLenArmHi = rLength2,
rLenThmbLo = rLength4,
rLenThmbHi = rLength8
};
/// Extract RelocPattern from normalized mach-o relocation.
static RelocPattern relocPattern(const normalized::Relocation &reloc);
/// Create normalized Relocation initialized from pattern.
static normalized::Relocation relocFromPattern(RelocPattern pattern);
/// One liner to add a relocation.
static void appendReloc(normalized::Relocations &relocs, uint32_t offset,
uint32_t symbol, uint32_t value,
RelocPattern pattern);
static int16_t readS16(bool swap, const uint8_t *addr);
static int32_t readS32(bool swap, const uint8_t *addr);
static uint32_t readU32(bool swap, const uint8_t *addr);
static int64_t readS64(bool swap, const uint8_t *addr);
};
} // namespace mach_o
} // namespace lld
#endif // LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
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