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//===- Target.h -------------------------------------------------*- C++ -*-===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_ELF_TARGET_H
#define LLD_ELF_TARGET_H
#include "llvm/ADT/StringRef.h"
#include "llvm/Object/ELF.h"
#include <memory>
namespace lld {
namespace elf {
class SymbolBody;
class TargetInfo {
public:
uint64_t getVAStart() const;
virtual bool isTlsInitialExecRel(uint32_t Type) const;
virtual bool pointsToLocalDynamicGotEntry(uint32_t Type) const;
virtual bool isTlsLocalDynamicRel(uint32_t Type) const;
virtual bool isTlsGlobalDynamicRel(uint32_t Type) const;
virtual uint32_t getDynRel(uint32_t Type) const { return Type; }
virtual uint32_t getTlsGotRel(uint32_t Type) const { return TlsGotRel; }
virtual void writeGotHeader(uint8_t *Buf) const {}
virtual void writeGotPltHeader(uint8_t *Buf) const {}
virtual void writeGotPlt(uint8_t *Buf, uint64_t Plt) const {};
// If lazy binding is supported, the first entry of the PLT has code
// to call the dynamic linker to resolve PLT entries the first time
// they are called. This function writes that code.
virtual void writePltZero(uint8_t *Buf) const {}
virtual void writePlt(uint8_t *Buf, uint64_t GotEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {}
// Returns true if a relocation is just a hint for linker to make for example
// some code optimization. Such relocations should not be handled as a regular
// ones and lead to dynamic relocation creation etc.
virtual bool isHintRel(uint32_t Type) const;
// Returns true if a relocation is relative to the place being relocated,
// such as relocations used for PC-relative instructions. Such relocations
// need not be fixed up if an image is loaded to a different address than
// the link-time address. So we don't have to emit a relocation for the
// dynamic linker if isRelRelative returns true.
virtual bool isRelRelative(uint32_t Type) const;
virtual bool isSizeRel(uint32_t Type) const;
virtual bool needsDynRelative(uint32_t Type) const { return false; }
virtual bool needsGot(uint32_t Type, SymbolBody &S) const;
virtual bool refersToGotEntry(uint32_t Type) const;
enum PltNeed { Plt_No, Plt_Explicit, Plt_Implicit };
template <class ELFT>
PltNeed needsPlt(uint32_t Type, const SymbolBody &S) const;
virtual void relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
uint64_t P, uint64_t SA, uint64_t ZA = 0,
uint8_t *PairedLoc = nullptr) const = 0;
virtual bool isGotRelative(uint32_t Type) const;
bool canRelaxTls(uint32_t Type, const SymbolBody *S) const;
template <class ELFT>
bool needsCopyRel(uint32_t Type, const SymbolBody &S) const;
size_t relaxTls(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type, uint64_t P,
uint64_t SA, const SymbolBody &S) const;
virtual ~TargetInfo();
unsigned PageSize = 4096;
// On freebsd x86_64 the first page cannot be mmaped.
// On linux that is controled by vm.mmap_min_addr. At least on some x86_64
// installs that is 65536, so the first 15 pages cannot be used.
// Given that, the smallest value that can be used in here is 0x10000.
// If using 2MB pages, the smallest page aligned address that works is
// 0x200000, but it looks like every OS uses 4k pages for executables.
uint64_t VAStart = 0x10000;
uint32_t CopyRel;
uint32_t GotRel;
uint32_t PltRel;
uint32_t RelativeRel;
uint32_t IRelativeRel;
uint32_t TlsGotRel = 0;
uint32_t TlsModuleIndexRel;
uint32_t TlsOffsetRel;
unsigned PltEntrySize = 8;
unsigned PltZeroSize = 0;
unsigned GotHeaderEntriesNum = 0;
unsigned GotPltHeaderEntriesNum = 3;
bool UseLazyBinding = false;
private:
virtual bool needsCopyRelImpl(uint32_t Type) const;
virtual bool needsPltImpl(uint32_t Type) const;
virtual size_t relaxTlsGdToIe(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
uint64_t P, uint64_t SA) const;
virtual size_t relaxTlsGdToLe(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
uint64_t P, uint64_t SA) const;
virtual size_t relaxTlsIeToLe(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
uint64_t P, uint64_t SA) const;
virtual size_t relaxTlsLdToLe(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
uint64_t P, uint64_t SA) const;
};
uint64_t getPPC64TocBase();
template <class ELFT> typename ELFT::uint getMipsGpAddr();
extern TargetInfo *Target;
TargetInfo *createTarget();
}
}
#endif