4b360292ed
The i386 glibc ld.so expects the .got.slot entry that is relocated by a R_386_IRELATIVE relocation to point directly at the ifunc resolver and not the address of the PLT entry + 6 (thus entering the lazy resolver). This is also the case for ARM and I suspect it is because these use REL relocations and can't use the addend field to store the address of the ifunc resolver. If the lazy resolver is used we get an error message stating that only R_386_JUMP_SLOT is supported. As ARM and i386 share the same code, I've removed the ARM specific test and added a writeIgotPlt() function that by default calls writeGotPlt(). ARM and i386 override this to write the address of the ifunc resolver. Differential Revision: https://reviews.llvm.org/D27581 llvm-svn: 289198
117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
//===- 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 "InputSection.h"
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include "llvm/Object/ELF.h"
|
|
|
|
#include <memory>
|
|
|
|
namespace lld {
|
|
namespace elf {
|
|
class InputFile;
|
|
class SymbolBody;
|
|
|
|
class TargetInfo {
|
|
public:
|
|
virtual bool isTlsInitialExecRel(uint32_t Type) const;
|
|
virtual bool isTlsLocalDynamicRel(uint32_t Type) const;
|
|
virtual bool isTlsGlobalDynamicRel(uint32_t Type) const;
|
|
virtual bool isPicRel(uint32_t Type) const { return true; }
|
|
virtual uint32_t getDynRel(uint32_t Type) const { return Type; }
|
|
virtual void writeGotPltHeader(uint8_t *Buf) const {}
|
|
virtual void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {};
|
|
virtual void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const;
|
|
virtual uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) 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 writePltHeader(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 only uses the low bits of a value such that
|
|
// all those bits are in in the same page. For example, if the relocation
|
|
// only uses the low 12 bits in a system with 4k pages. If this is true, the
|
|
// bits will always have the same value at runtime and we don't have to emit
|
|
// a dynamic relocation.
|
|
virtual bool usesOnlyLowPageBits(uint32_t Type) const;
|
|
|
|
// Decide whether a Thunk is needed for the relocation from File
|
|
// targeting S. Returns one of:
|
|
// Expr if there is no Thunk required
|
|
// R_THUNK_ABS if thunk is required and expression is absolute
|
|
// R_THUNK_PC if thunk is required and expression is pc rel
|
|
// R_THUNK_PLT_PC if thunk is required to PLT entry and expression is pc rel
|
|
virtual RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType,
|
|
const InputFile &File,
|
|
const SymbolBody &S) const;
|
|
virtual RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const = 0;
|
|
virtual void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const = 0;
|
|
virtual ~TargetInfo();
|
|
|
|
unsigned TlsGdRelaxSkip = 1;
|
|
unsigned PageSize = 4096;
|
|
unsigned DefaultMaxPageSize = 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.
|
|
uint64_t DefaultImageBase = 0x10000;
|
|
|
|
uint32_t CopyRel;
|
|
uint32_t GotRel;
|
|
uint32_t PltRel;
|
|
uint32_t RelativeRel;
|
|
uint32_t IRelativeRel;
|
|
uint32_t TlsDescRel;
|
|
uint32_t TlsGotRel;
|
|
uint32_t TlsModuleIndexRel;
|
|
uint32_t TlsOffsetRel;
|
|
unsigned GotEntrySize = 0;
|
|
unsigned GotPltEntrySize = 0;
|
|
unsigned PltEntrySize;
|
|
unsigned PltHeaderSize;
|
|
|
|
// At least on x86_64 positions 1 and 2 are used by the first plt entry
|
|
// to support lazy loading.
|
|
unsigned GotPltHeaderEntriesNum = 3;
|
|
|
|
// Set to 0 for variant 2
|
|
unsigned TcbSize = 0;
|
|
|
|
bool NeedsThunks = false;
|
|
|
|
virtual RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
|
|
RelExpr Expr) const;
|
|
virtual void relaxGot(uint8_t *Loc, uint64_t Val) const;
|
|
virtual void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
|
|
virtual void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
|
|
virtual void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
|
|
virtual void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
|
|
};
|
|
|
|
std::string toString(uint32_t RelType);
|
|
uint64_t getPPC64TocBase();
|
|
uint64_t getAArch64Page(uint64_t Expr);
|
|
|
|
extern TargetInfo *Target;
|
|
TargetInfo *createTarget();
|
|
}
|
|
}
|
|
|
|
#endif
|