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//===- Target.cpp ---------------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Machine-specific things, such as applying relocations, creation of
// GOT or PLT entries, etc., are handled in this file.
//
// Refer the ELF spec for the single letter variables, S, A or P, used
// in this file.
//
// Some functions defined in this file has "relaxTls" as part of their names.
// They do peephole optimization for TLS variables by rewriting instructions.
// They are not part of the ABI but optional optimization, so you can skip
// them if you are not interested in how TLS variables are optimized.
// See the following paper for the details.
//
// Ulrich Drepper, ELF Handling For Thread-Local Storage
// http://www.akkadia.org/drepper/tls.pdf
//
//===----------------------------------------------------------------------===//
#include "Target.h"
#include "InputFiles.h"
#include "OutputSections.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/Object/ELF.h"
using namespace llvm;
using namespace llvm::object;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf;
TargetInfo *elf::Target;
std::string lld::toString(RelType Type) {
StringRef S = getELFRelocationTypeName(elf::Config->EMachine, Type);
if (S == "Unknown")
return ("Unknown (" + Twine(Type) + ")").str();
return S;
}
TargetInfo *elf::getTarget() {
switch (Config->EMachine) {
case EM_386:
case EM_IAMCU:
return getX86TargetInfo();
case EM_AARCH64:
return getAArch64TargetInfo();
case EM_AMDGPU:
return getAMDGPUTargetInfo();
case EM_ARM:
return getARMTargetInfo();
case EM_AVR:
return getAVRTargetInfo();
case EM_HEXAGON:
return getHexagonTargetInfo();
case EM_MIPS:
switch (Config->EKind) {
case ELF32LEKind:
return getMipsTargetInfo<ELF32LE>();
case ELF32BEKind:
return getMipsTargetInfo<ELF32BE>();
case ELF64LEKind:
return getMipsTargetInfo<ELF64LE>();
case ELF64BEKind:
return getMipsTargetInfo<ELF64BE>();
default:
fatal("unsupported MIPS target");
}
case EM_PPC:
return getPPCTargetInfo();
case EM_PPC64:
return getPPC64TargetInfo();
case EM_SPARCV9:
return getSPARCV9TargetInfo();
case EM_X86_64:
if (Config->EKind == ELF32LEKind)
return getX32TargetInfo();
return getX86_64TargetInfo();
}
fatal("unknown target machine");
}
template <class ELFT> static ErrorPlace getErrPlace(const uint8_t *Loc) {
for (InputSectionBase *D : InputSections) {
auto *IS = cast<InputSection>(D);
if (!IS->getParent())
continue;
uint8_t *ISLoc = IS->getParent()->Loc + IS->OutSecOff;
if (ISLoc <= Loc && Loc < ISLoc + IS->getSize())
return {IS, IS->template getLocation<ELFT>(Loc - ISLoc) + ": "};
}
return {};
}
ErrorPlace elf::getErrorPlace(const uint8_t *Loc) {
switch (Config->EKind) {
case ELF32LEKind:
return getErrPlace<ELF32LE>(Loc);
case ELF32BEKind:
return getErrPlace<ELF32BE>(Loc);
case ELF64LEKind:
return getErrPlace<ELF64LE>(Loc);
case ELF64BEKind:
return getErrPlace<ELF64BE>(Loc);
default:
llvm_unreachable("unknown ELF type");
}
}
TargetInfo::~TargetInfo() {}
int64_t TargetInfo::getImplicitAddend(const uint8_t *Buf, RelType Type) const {
return 0;
}
bool TargetInfo::usesOnlyLowPageBits(RelType Type) const { return false; }
bool TargetInfo::needsThunk(RelExpr Expr, RelType Type, const InputFile *File,
uint64_t BranchAddr, const Symbol &S) const {
return false;
}
bool TargetInfo::adjustPrologueForCrossSplitStack(uint8_t *Loc,
uint8_t *End) const {
llvm_unreachable("Target doesn't support split stacks.");
}
bool TargetInfo::inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const {
return true;
}
void TargetInfo::writeIgotPlt(uint8_t *Buf, const Symbol &S) const {
writeGotPlt(Buf, S);
}
RelExpr TargetInfo::adjustRelaxExpr(RelType Type, const uint8_t *Data,
RelExpr Expr) const {
return Expr;
}
void TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsGdToLe(uint8_t *Loc, RelType Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsGdToIe(uint8_t *Loc, RelType Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsIeToLe(uint8_t *Loc, RelType Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsLdToLe(uint8_t *Loc, RelType Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
uint64_t TargetInfo::getImageBase() {
// Use -image-base if set. Fall back to the target default if not.
if (Config->ImageBase)
return *Config->ImageBase;
return Config->Pic ? 0 : DefaultImageBase;
}
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