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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 "Error.h"
#include "InputFiles.h"
#include "Memory.h"
#include "OutputSections.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "Thunks.h"
#include "Writer.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
using namespace llvm::object;
using namespace llvm::support::endian;
using namespace llvm::ELF;
std::string lld::toString(uint32_t Type) {
StringRef S = getELFRelocationTypeName(elf::Config->EMachine, Type);
if (S == "Unknown")
return ("Unknown (" + Twine(Type) + ")").str();
return S;
}
namespace lld {
namespace elf {
TargetInfo *Target;
static void or32le(uint8_t *P, int32_t V) { write32le(P, read32le(P) | V); }
static void or32be(uint8_t *P, int32_t V) { write32be(P, read32be(P) | V); }
template <class ELFT> static std::string getErrorLoc(const uint8_t *Loc) {
for (InputSectionBase *D : InputSections) {
auto *IS = dyn_cast_or_null<InputSection>(D);
if (!IS || !IS->OutSec)
continue;
uint8_t *ISLoc = cast<OutputSection>(IS->OutSec)->Loc + IS->OutSecOff;
if (ISLoc <= Loc && Loc < ISLoc + IS->getSize())
return IS->template getLocation<ELFT>(Loc - ISLoc) + ": ";
}
return "";
}
static std::string getErrorLocation(const uint8_t *Loc) {
switch (Config->EKind) {
case ELF32LEKind:
return getErrorLoc<ELF32LE>(Loc);
case ELF32BEKind:
return getErrorLoc<ELF32BE>(Loc);
case ELF64LEKind:
return getErrorLoc<ELF64LE>(Loc);
case ELF64BEKind:
return getErrorLoc<ELF64BE>(Loc);
default:
llvm_unreachable("unknown ELF type");
}
}
template <unsigned N>
static void checkInt(uint8_t *Loc, int64_t V, uint32_t Type) {
if (!isInt<N>(V))
error(getErrorLocation(Loc) + "relocation " + toString(Type) +
" out of range");
}
template <unsigned N>
static void checkUInt(uint8_t *Loc, uint64_t V, uint32_t Type) {
if (!isUInt<N>(V))
error(getErrorLocation(Loc) + "relocation " + toString(Type) +
" out of range");
}
template <unsigned N>
static void checkIntUInt(uint8_t *Loc, uint64_t V, uint32_t Type) {
if (!isInt<N>(V) && !isUInt<N>(V))
error(getErrorLocation(Loc) + "relocation " + toString(Type) +
" out of range");
}
template <unsigned N>
static void checkAlignment(uint8_t *Loc, uint64_t V, uint32_t Type) {
if ((V & (N - 1)) != 0)
error(getErrorLocation(Loc) + "improper alignment for relocation " +
toString(Type));
}
namespace {
class X86TargetInfo final : public TargetInfo {
public:
X86TargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override;
void writeGotPltHeader(uint8_t *Buf) const override;
uint32_t getDynRel(uint32_t Type) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writePltHeader(uint8_t *Buf) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
RelExpr Expr) const override;
void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
};
template <class ELFT> class X86_64TargetInfo final : public TargetInfo {
public:
X86_64TargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
bool isPicRel(uint32_t Type) const override;
void writeGotPltHeader(uint8_t *Buf) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writePltHeader(uint8_t *Buf) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
RelExpr Expr) const override;
void relaxGot(uint8_t *Loc, uint64_t Val) const override;
void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
private:
void relaxGotNoPic(uint8_t *Loc, uint64_t Val, uint8_t Op,
uint8_t ModRm) const;
};
class PPCTargetInfo final : public TargetInfo {
public:
PPCTargetInfo();
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
};
class PPC64TargetInfo final : public TargetInfo {
public:
PPC64TargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
};
class AArch64TargetInfo final : public TargetInfo {
public:
AArch64TargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
bool isPicRel(uint32_t Type) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writePltHeader(uint8_t *Buf) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
bool usesOnlyLowPageBits(uint32_t Type) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
RelExpr Expr) const override;
void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
};
class AMDGPUTargetInfo final : public TargetInfo {
public:
AMDGPUTargetInfo();
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
};
class ARMTargetInfo final : public TargetInfo {
public:
ARMTargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
bool isPicRel(uint32_t Type) const override;
uint32_t getDynRel(uint32_t Type) const override;
int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writePltHeader(uint8_t *Buf) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
void addPltSymbols(InputSectionBase *IS, uint64_t Off) const override;
void addPltHeaderSymbols(InputSectionBase *ISD) const override;
bool needsThunk(RelExpr Expr, uint32_t RelocType, const InputFile *File,
const SymbolBody &S) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
};
template <class ELFT> class MipsTargetInfo final : public TargetInfo {
public:
MipsTargetInfo();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override;
int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override;
bool isPicRel(uint32_t Type) const override;
uint32_t getDynRel(uint32_t Type) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
void writePltHeader(uint8_t *Buf) const override;
void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr,
int32_t Index, unsigned RelOff) const override;
bool needsThunk(RelExpr Expr, uint32_t RelocType, const InputFile *File,
const SymbolBody &S) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
bool usesOnlyLowPageBits(uint32_t Type) const override;
};
} // anonymous namespace
TargetInfo *createTarget() {
switch (Config->EMachine) {
case EM_386:
case EM_IAMCU:
return make<X86TargetInfo>();
case EM_AARCH64:
return make<AArch64TargetInfo>();
case EM_AMDGPU:
return make<AMDGPUTargetInfo>();
case EM_ARM:
return make<ARMTargetInfo>();
case EM_MIPS:
switch (Config->EKind) {
case ELF32LEKind:
return make<MipsTargetInfo<ELF32LE>>();
case ELF32BEKind:
return make<MipsTargetInfo<ELF32BE>>();
case ELF64LEKind:
return make<MipsTargetInfo<ELF64LE>>();
case ELF64BEKind:
return make<MipsTargetInfo<ELF64BE>>();
default:
fatal("unsupported MIPS target");
}
case EM_PPC:
return make<PPCTargetInfo>();
case EM_PPC64:
return make<PPC64TargetInfo>();
case EM_X86_64:
if (Config->EKind == ELF32LEKind)
return make<X86_64TargetInfo<ELF32LE>>();
return make<X86_64TargetInfo<ELF64LE>>();
}
fatal("unknown target machine");
}
TargetInfo::~TargetInfo() {}
int64_t TargetInfo::getImplicitAddend(const uint8_t *Buf, uint32_t Type) const {
return 0;
}
bool TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { return false; }
bool TargetInfo::needsThunk(RelExpr Expr, uint32_t RelocType,
const InputFile *File, const SymbolBody &S) const {
return false;
}
void TargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const {
writeGotPlt(Buf, S);
}
RelExpr TargetInfo::adjustRelaxExpr(uint32_t 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, uint32_t Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
X86TargetInfo::X86TargetInfo() {
CopyRel = R_386_COPY;
GotRel = R_386_GLOB_DAT;
PltRel = R_386_JUMP_SLOT;
IRelativeRel = R_386_IRELATIVE;
RelativeRel = R_386_RELATIVE;
TlsGotRel = R_386_TLS_TPOFF;
TlsModuleIndexRel = R_386_TLS_DTPMOD32;
TlsOffsetRel = R_386_TLS_DTPOFF32;
GotEntrySize = 4;
GotPltEntrySize = 4;
PltEntrySize = 16;
PltHeaderSize = 16;
TlsGdRelaxSkip = 2;
// 0xCC is the "int3" (call debug exception handler) instruction.
TrapInstr = 0xcccccccc;
}
RelExpr X86TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
case R_386_8:
case R_386_16:
case R_386_32:
case R_386_TLS_LDO_32:
return R_ABS;
case R_386_TLS_GD:
return R_TLSGD;
case R_386_TLS_LDM:
return R_TLSLD;
case R_386_PLT32:
return R_PLT_PC;
case R_386_PC8:
case R_386_PC16:
case R_386_PC32:
return R_PC;
case R_386_GOTPC:
return R_GOTONLY_PC_FROM_END;
case R_386_TLS_IE:
return R_GOT;
case R_386_GOT32:
case R_386_GOT32X:
// These relocations can be calculated in two different ways.
// Usual calculation is G + A - GOT what means an offset in GOT table
// (R_GOT_FROM_END). When instruction pointed by relocation has no base
// register, then relocations can be used when PIC code is disabled. In that
// case calculation is G + A, it resolves to an address of entry in GOT
// (R_GOT) and not an offset.
//
// To check that instruction has no base register we scan ModR/M byte.
// See "Table 2-2. 32-Bit Addressing Forms with the ModR/M Byte"
// (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/
// 64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf)
if ((Loc[-1] & 0xc7) != 0x5)
return R_GOT_FROM_END;
if (Config->Pic)
error(toString(S.File) + ": relocation " + toString(Type) + " against '" +
S.getName() +
"' without base register can not be used when PIC enabled");
return R_GOT;
case R_386_TLS_GOTIE:
return R_GOT_FROM_END;
case R_386_GOTOFF:
return R_GOTREL_FROM_END;
case R_386_TLS_LE:
return R_TLS;
case R_386_TLS_LE_32:
return R_NEG_TLS;
case R_386_NONE:
return R_NONE;
default:
error(toString(S.File) + ": unknown relocation type: " + toString(Type));
return R_HINT;
}
}
RelExpr X86TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
RelExpr Expr) const {
switch (Expr) {
default:
return Expr;
case R_RELAX_TLS_GD_TO_IE:
return R_RELAX_TLS_GD_TO_IE_END;
case R_RELAX_TLS_GD_TO_LE:
return R_RELAX_TLS_GD_TO_LE_NEG;
}
}
void X86TargetInfo::writeGotPltHeader(uint8_t *Buf) const {
write32le(Buf, InX::Dynamic->getVA());
}
void X86TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {
// Entries in .got.plt initially points back to the corresponding
// PLT entries with a fixed offset to skip the first instruction.
write32le(Buf, S.getPltVA() + 6);
}
void X86TargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const {
// An x86 entry is the address of the ifunc resolver function.
write32le(Buf, S.getVA());
}
uint32_t X86TargetInfo::getDynRel(uint32_t Type) const {
if (Type == R_386_TLS_LE)
return R_386_TLS_TPOFF;
if (Type == R_386_TLS_LE_32)
return R_386_TLS_TPOFF32;
return Type;
}
void X86TargetInfo::writePltHeader(uint8_t *Buf) const {
if (Config->Pic) {
const uint8_t V[] = {
0xff, 0xb3, 0x04, 0x00, 0x00, 0x00, // pushl GOTPLT+4(%ebx)
0xff, 0xa3, 0x08, 0x00, 0x00, 0x00, // jmp *GOTPLT+8(%ebx)
0x90, 0x90, 0x90, 0x90 // nop
};
memcpy(Buf, V, sizeof(V));
uint32_t Ebx = InX::Got->getVA() + InX::Got->getSize();
uint32_t GotPlt = InX::GotPlt->getVA() - Ebx;
write32le(Buf + 2, GotPlt + 4);
write32le(Buf + 8, GotPlt + 8);
return;
}
const uint8_t PltData[] = {
0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushl (GOTPLT+4)
0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *(GOTPLT+8)
0x90, 0x90, 0x90, 0x90 // nop
};
memcpy(Buf, PltData, sizeof(PltData));
uint32_t GotPlt = InX::GotPlt->getVA();
write32le(Buf + 2, GotPlt + 4);
write32le(Buf + 8, GotPlt + 8);
}
void X86TargetInfo::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const uint8_t Inst[] = {
0xff, 0x00, 0x00, 0x00, 0x00, 0x00, // jmp *foo_in_GOT|*foo@GOT(%ebx)
0x68, 0x00, 0x00, 0x00, 0x00, // pushl $reloc_offset
0xe9, 0x00, 0x00, 0x00, 0x00 // jmp .PLT0@PC
};
memcpy(Buf, Inst, sizeof(Inst));
if (Config->Pic) {
// jmp *foo@GOT(%ebx)
uint32_t Ebx = InX::Got->getVA() + InX::Got->getSize();
Buf[1] = 0xa3;
write32le(Buf + 2, GotPltEntryAddr - Ebx);
} else {
// jmp *foo_in_GOT
Buf[1] = 0x25;
write32le(Buf + 2, GotPltEntryAddr);
}
write32le(Buf + 7, RelOff);
write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16);
}
int64_t X86TargetInfo::getImplicitAddend(const uint8_t *Buf,
uint32_t Type) const {
switch (Type) {
default:
return 0;
case R_386_8:
case R_386_PC8:
return SignExtend64<8>(*Buf);
case R_386_16:
case R_386_PC16:
return SignExtend64<16>(read16le(Buf));
case R_386_32:
case R_386_GOT32:
case R_386_GOT32X:
case R_386_GOTOFF:
case R_386_GOTPC:
case R_386_PC32:
case R_386_PLT32:
case R_386_TLS_LDO_32:
case R_386_TLS_LE:
return SignExtend64<32>(read32le(Buf));
}
}
void X86TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// R_386_{PC,}{8,16} are not part of the i386 psABI, but they are
// being used for some 16-bit programs such as boot loaders, so
// we want to support them.
switch (Type) {
case R_386_8:
checkUInt<8>(Loc, Val, Type);
*Loc = Val;
break;
case R_386_PC8:
checkInt<8>(Loc, Val, Type);
*Loc = Val;
break;
case R_386_16:
checkUInt<16>(Loc, Val, Type);
write16le(Loc, Val);
break;
case R_386_PC16:
checkInt<16>(Loc, Val, Type);
write16le(Loc, Val);
break;
default:
checkInt<32>(Loc, Val, Type);
write32le(Loc, Val);
}
}
void X86TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Convert
// leal x@tlsgd(, %ebx, 1),
// call __tls_get_addr@plt
// to
// movl %gs:0,%eax
// subl $x@ntpoff,%eax
const uint8_t Inst[] = {
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax
0x81, 0xe8, 0x00, 0x00, 0x00, 0x00 // subl 0(%ebx), %eax
};
memcpy(Loc - 3, Inst, sizeof(Inst));
write32le(Loc + 5, Val);
}
void X86TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Convert
// leal x@tlsgd(, %ebx, 1),
// call __tls_get_addr@plt
// to
// movl %gs:0, %eax
// addl x@gotntpoff(%ebx), %eax
const uint8_t Inst[] = {
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax
0x03, 0x83, 0x00, 0x00, 0x00, 0x00 // addl 0(%ebx), %eax
};
memcpy(Loc - 3, Inst, sizeof(Inst));
write32le(Loc + 5, Val);
}
// In some conditions, relocations can be optimized to avoid using GOT.
// This function does that for Initial Exec to Local Exec case.
void X86TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Ulrich's document section 6.2 says that @gotntpoff can
// be used with MOVL or ADDL instructions.
// @indntpoff is similar to @gotntpoff, but for use in
// position dependent code.
uint8_t Reg = (Loc[-1] >> 3) & 7;
if (Type == R_386_TLS_IE) {
if (Loc[-1] == 0xa1) {
// "movl foo@indntpoff,%eax" -> "movl $foo,%eax"
// This case is different from the generic case below because
// this is a 5 byte instruction while below is 6 bytes.
Loc[-1] = 0xb8;
} else if (Loc[-2] == 0x8b) {
// "movl foo@indntpoff,%reg" -> "movl $foo,%reg"
Loc[-2] = 0xc7;
Loc[-1] = 0xc0 | Reg;
} else {
// "addl foo@indntpoff,%reg" -> "addl $foo,%reg"
Loc[-2] = 0x81;
Loc[-1] = 0xc0 | Reg;
}
} else {
assert(Type == R_386_TLS_GOTIE);
if (Loc[-2] == 0x8b) {
// "movl foo@gottpoff(%rip),%reg" -> "movl $foo,%reg"
Loc[-2] = 0xc7;
Loc[-1] = 0xc0 | Reg;
} else {
// "addl foo@gotntpoff(%rip),%reg" -> "leal foo(%reg),%reg"
Loc[-2] = 0x8d;
Loc[-1] = 0x80 | (Reg << 3) | Reg;
}
}
write32le(Loc, Val);
}
void X86TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
if (Type == R_386_TLS_LDO_32) {
write32le(Loc, Val);
return;
}
// Convert
// leal foo(%reg),%eax
// call ___tls_get_addr
// to
// movl %gs:0,%eax
// nop
// leal 0(%esi,1),%esi
const uint8_t Inst[] = {
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0,%eax
0x90, // nop
0x8d, 0x74, 0x26, 0x00 // leal 0(%esi,1),%esi
};
memcpy(Loc - 2, Inst, sizeof(Inst));
}
template <class ELFT> X86_64TargetInfo<ELFT>::X86_64TargetInfo() {
CopyRel = R_X86_64_COPY;
GotRel = R_X86_64_GLOB_DAT;
PltRel = R_X86_64_JUMP_SLOT;
RelativeRel = R_X86_64_RELATIVE;
IRelativeRel = R_X86_64_IRELATIVE;
TlsGotRel = R_X86_64_TPOFF64;
TlsModuleIndexRel = R_X86_64_DTPMOD64;
TlsOffsetRel = R_X86_64_DTPOFF64;
GotEntrySize = 8;
GotPltEntrySize = 8;
PltEntrySize = 16;
PltHeaderSize = 16;
TlsGdRelaxSkip = 2;
// Align to the large page size (known as a superpage or huge page).
// FreeBSD automatically promotes large, superpage-aligned allocations.
DefaultImageBase = 0x200000;
// 0xCC is the "int3" (call debug exception handler) instruction.
TrapInstr = 0xcccccccc;
}
template <class ELFT>
RelExpr X86_64TargetInfo<ELFT>::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
case R_X86_64_8:
case R_X86_64_16:
case R_X86_64_32:
case R_X86_64_32S:
case R_X86_64_64:
case R_X86_64_DTPOFF32:
case R_X86_64_DTPOFF64:
return R_ABS;
case R_X86_64_TPOFF32:
return R_TLS;
case R_X86_64_TLSLD:
return R_TLSLD_PC;
case R_X86_64_TLSGD:
return R_TLSGD_PC;
case R_X86_64_SIZE32:
case R_X86_64_SIZE64:
return R_SIZE;
case R_X86_64_PLT32:
return R_PLT_PC;
case R_X86_64_PC32:
case R_X86_64_PC64:
return R_PC;
case R_X86_64_GOT32:
case R_X86_64_GOT64:
return R_GOT_FROM_END;
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_GOTTPOFF:
return R_GOT_PC;
case R_X86_64_NONE:
return R_NONE;
default:
error(toString(S.File) + ": unknown relocation type: " + toString(Type));
return R_HINT;
}
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::writeGotPltHeader(uint8_t *Buf) const {
// The first entry holds the value of _DYNAMIC. It is not clear why that is
// required, but it is documented in the psabi and the glibc dynamic linker
// seems to use it (note that this is relevant for linking ld.so, not any
// other program).
write64le(Buf, InX::Dynamic->getVA());
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::writeGotPlt(uint8_t *Buf,
const SymbolBody &S) const {
// See comments in X86TargetInfo::writeGotPlt.
write32le(Buf, S.getPltVA() + 6);
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const {
const uint8_t PltData[] = {
0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushq GOTPLT+8(%rip)
0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *GOTPLT+16(%rip)
0x0f, 0x1f, 0x40, 0x00 // nop
};
memcpy(Buf, PltData, sizeof(PltData));
uint64_t GotPlt = InX::GotPlt->getVA();
uint64_t Plt = InX::Plt->getVA();
write32le(Buf + 2, GotPlt - Plt + 2); // GOTPLT+8
write32le(Buf + 8, GotPlt - Plt + 4); // GOTPLT+16
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const uint8_t Inst[] = {
0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmpq *got(%rip)
0x68, 0x00, 0x00, 0x00, 0x00, // pushq <relocation index>
0xe9, 0x00, 0x00, 0x00, 0x00 // jmpq plt[0]
};
memcpy(Buf, Inst, sizeof(Inst));
write32le(Buf + 2, GotPltEntryAddr - PltEntryAddr - 6);
write32le(Buf + 7, Index);
write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16);
}
template <class ELFT>
bool X86_64TargetInfo<ELFT>::isPicRel(uint32_t Type) const {
return Type != R_X86_64_PC32 && Type != R_X86_64_32 &&
Type != R_X86_64_TPOFF32;
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Convert
// .byte 0x66
// leaq x@tlsgd(%rip), %rdi
// .word 0x6666
// rex64
// call __tls_get_addr@plt
// to
// mov %fs:0x0,%rax
// lea x@tpoff,%rax
const uint8_t Inst[] = {
0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax
0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff,%rax
};
memcpy(Loc - 4, Inst, sizeof(Inst));
// The original code used a pc relative relocation and so we have to
// compensate for the -4 in had in the addend.
write32le(Loc + 8, Val + 4);
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Convert
// .byte 0x66
// leaq x@tlsgd(%rip), %rdi
// .word 0x6666
// rex64
// call __tls_get_addr@plt
// to
// mov %fs:0x0,%rax
// addq x@tpoff,%rax
const uint8_t Inst[] = {
0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax
0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // addq x@tpoff,%rax
};
memcpy(Loc - 4, Inst, sizeof(Inst));
// Both code sequences are PC relatives, but since we are moving the constant
// forward by 8 bytes we have to subtract the value by 8.
write32le(Loc + 8, Val - 8);
}
// In some conditions, R_X86_64_GOTTPOFF relocation can be optimized to
// R_X86_64_TPOFF32 so that it does not use GOT.
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
uint8_t *Inst = Loc - 3;
uint8_t Reg = Loc[-1] >> 3;
uint8_t *RegSlot = Loc - 1;
// Note that ADD with RSP or R12 is converted to ADD instead of LEA
// because LEA with these registers needs 4 bytes to encode and thus
// wouldn't fit the space.
if (memcmp(Inst, "\x48\x03\x25", 3) == 0) {
// "addq foo@gottpoff(%rip),%rsp" -> "addq $foo,%rsp"
memcpy(Inst, "\x48\x81\xc4", 3);
} else if (memcmp(Inst, "\x4c\x03\x25", 3) == 0) {
// "addq foo@gottpoff(%rip),%r12" -> "addq $foo,%r12"
memcpy(Inst, "\x49\x81\xc4", 3);
} else if (memcmp(Inst, "\x4c\x03", 2) == 0) {
// "addq foo@gottpoff(%rip),%r[8-15]" -> "leaq foo(%r[8-15]),%r[8-15]"
memcpy(Inst, "\x4d\x8d", 2);
*RegSlot = 0x80 | (Reg << 3) | Reg;
} else if (memcmp(Inst, "\x48\x03", 2) == 0) {
// "addq foo@gottpoff(%rip),%reg -> "leaq foo(%reg),%reg"
memcpy(Inst, "\x48\x8d", 2);
*RegSlot = 0x80 | (Reg << 3) | Reg;
} else if (memcmp(Inst, "\x4c\x8b", 2) == 0) {
// "movq foo@gottpoff(%rip),%r[8-15]" -> "movq $foo,%r[8-15]"
memcpy(Inst, "\x49\xc7", 2);
*RegSlot = 0xc0 | Reg;
} else if (memcmp(Inst, "\x48\x8b", 2) == 0) {
// "movq foo@gottpoff(%rip),%reg" -> "movq $foo,%reg"
memcpy(Inst, "\x48\xc7", 2);
*RegSlot = 0xc0 | Reg;
} else {
error(getErrorLocation(Loc - 3) +
"R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only");
}
// The original code used a PC relative relocation.
// Need to compensate for the -4 it had in the addend.
write32le(Loc, Val + 4);
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// Convert
// leaq bar@tlsld(%rip), %rdi
// callq __tls_get_addr@PLT
// leaq bar@dtpoff(%rax), %rcx
// to
// .word 0x6666
// .byte 0x66
// mov %fs:0,%rax
// leaq bar@tpoff(%rax), %rcx
if (Type == R_X86_64_DTPOFF64) {
write64le(Loc, Val);
return;
}
if (Type == R_X86_64_DTPOFF32) {
write32le(Loc, Val);
return;
}
const uint8_t Inst[] = {
0x66, 0x66, // .word 0x6666
0x66, // .byte 0x66
0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax
};
memcpy(Loc - 3, Inst, sizeof(Inst));
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
switch (Type) {
case R_X86_64_8:
checkUInt<8>(Loc, Val, Type);
*Loc = Val;
break;
case R_X86_64_16:
checkUInt<16>(Loc, Val, Type);
write16le(Loc, Val);
break;
case R_X86_64_32:
checkUInt<32>(Loc, Val, Type);
write32le(Loc, Val);
break;
case R_X86_64_32S:
case R_X86_64_TPOFF32:
case R_X86_64_GOT32:
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_PC32:
case R_X86_64_GOTTPOFF:
case R_X86_64_PLT32:
case R_X86_64_TLSGD:
case R_X86_64_TLSLD:
case R_X86_64_DTPOFF32:
case R_X86_64_SIZE32:
checkInt<32>(Loc, Val, Type);
write32le(Loc, Val);
break;
case R_X86_64_64:
case R_X86_64_DTPOFF64:
case R_X86_64_GLOB_DAT:
case R_X86_64_PC64:
case R_X86_64_SIZE64:
case R_X86_64_GOT64:
write64le(Loc, Val);
break;
default:
llvm_unreachable("unexpected relocation");
}
}
template <class ELFT>
RelExpr X86_64TargetInfo<ELFT>::adjustRelaxExpr(uint32_t Type,
const uint8_t *Data,
RelExpr RelExpr) const {
if (Type != R_X86_64_GOTPCRELX && Type != R_X86_64_REX_GOTPCRELX)
return RelExpr;
const uint8_t Op = Data[-2];
const uint8_t ModRm = Data[-1];
// FIXME: When PIC is disabled and foo is defined locally in the
// lower 32 bit address space, memory operand in mov can be converted into
// immediate operand. Otherwise, mov must be changed to lea. We support only
// latter relaxation at this moment.
if (Op == 0x8b)
return R_RELAX_GOT_PC;
// Relax call and jmp.
if (Op == 0xff && (ModRm == 0x15 || ModRm == 0x25))
return R_RELAX_GOT_PC;
// Relaxation of test, adc, add, and, cmp, or, sbb, sub, xor.
// If PIC then no relaxation is available.
// We also don't relax test/binop instructions without REX byte,
// they are 32bit operations and not common to have.
assert(Type == R_X86_64_REX_GOTPCRELX);
return Config->Pic ? RelExpr : R_RELAX_GOT_PC_NOPIC;
}
// A subset of relaxations can only be applied for no-PIC. This method
// handles such relaxations. Instructions encoding information was taken from:
// "Intel 64 and IA-32 Architectures Software Developer's Manual V2"
// (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/
// 64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf)
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxGotNoPic(uint8_t *Loc, uint64_t Val,
uint8_t Op, uint8_t ModRm) const {
const uint8_t Rex = Loc[-3];
// Convert "test %reg, foo@GOTPCREL(%rip)" to "test $foo, %reg".
if (Op == 0x85) {
// See "TEST-Logical Compare" (4-428 Vol. 2B),
// TEST r/m64, r64 uses "full" ModR / M byte (no opcode extension).
// ModR/M byte has form XX YYY ZZZ, where
// YYY is MODRM.reg(register 2), ZZZ is MODRM.rm(register 1).
// XX has different meanings:
// 00: The operand's memory address is in reg1.
// 01: The operand's memory address is reg1 + a byte-sized displacement.
// 10: The operand's memory address is reg1 + a word-sized displacement.
// 11: The operand is reg1 itself.
// If an instruction requires only one operand, the unused reg2 field
// holds extra opcode bits rather than a register code
// 0xC0 == 11 000 000 binary.
// 0x38 == 00 111 000 binary.
// We transfer reg2 to reg1 here as operand.
// See "2.1.3 ModR/M and SIB Bytes" (Vol. 2A 2-3).
Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3; // ModR/M byte.
// Change opcode from TEST r/m64, r64 to TEST r/m64, imm32
// See "TEST-Logical Compare" (4-428 Vol. 2B).
Loc[-2] = 0xf7;
// Move R bit to the B bit in REX byte.
// REX byte is encoded as 0100WRXB, where
// 0100 is 4bit fixed pattern.
// REX.W When 1, a 64-bit operand size is used. Otherwise, when 0, the
// default operand size is used (which is 32-bit for most but not all
// instructions).
// REX.R This 1-bit value is an extension to the MODRM.reg field.
// REX.X This 1-bit value is an extension to the SIB.index field.
// REX.B This 1-bit value is an extension to the MODRM.rm field or the
// SIB.base field.
// See "2.2.1.2 More on REX Prefix Fields " (2-8 Vol. 2A).
Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2;
write32le(Loc, Val);
return;
}
// If we are here then we need to relax the adc, add, and, cmp, or, sbb, sub
// or xor operations.
// Convert "binop foo@GOTPCREL(%rip), %reg" to "binop $foo, %reg".
// Logic is close to one for test instruction above, but we also
// write opcode extension here, see below for details.
Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3 | (Op & 0x3c); // ModR/M byte.
// Primary opcode is 0x81, opcode extension is one of:
// 000b = ADD, 001b is OR, 010b is ADC, 011b is SBB,
// 100b is AND, 101b is SUB, 110b is XOR, 111b is CMP.
// This value was wrote to MODRM.reg in a line above.
// See "3.2 INSTRUCTIONS (A-M)" (Vol. 2A 3-15),
// "INSTRUCTION SET REFERENCE, N-Z" (Vol. 2B 4-1) for
// descriptions about each operation.
Loc[-2] = 0x81;
Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2;
write32le(Loc, Val);
}
template <class ELFT>
void X86_64TargetInfo<ELFT>::relaxGot(uint8_t *Loc, uint64_t Val) const {
const uint8_t Op = Loc[-2];
const uint8_t ModRm = Loc[-1];
// Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg".
if (Op == 0x8b) {
Loc[-2] = 0x8d;
write32le(Loc, Val);
return;
}
if (Op != 0xff) {
// We are relaxing a rip relative to an absolute, so compensate
// for the old -4 addend.
assert(!Config->Pic);
relaxGotNoPic(Loc, Val + 4, Op, ModRm);
return;
}
// Convert call/jmp instructions.
if (ModRm == 0x15) {
// ABI says we can convert "call *foo@GOTPCREL(%rip)" to "nop; call foo".
// Instead we convert to "addr32 call foo" where addr32 is an instruction
// prefix. That makes result expression to be a single instruction.
Loc[-2] = 0x67; // addr32 prefix
Loc[-1] = 0xe8; // call
write32le(Loc, Val);
return;
}
// Convert "jmp *foo@GOTPCREL(%rip)" to "jmp foo; nop".
// jmp doesn't return, so it is fine to use nop here, it is just a stub.
assert(ModRm == 0x25);
Loc[-2] = 0xe9; // jmp
Loc[3] = 0x90; // nop
write32le(Loc - 1, Val + 1);
}
// Relocation masks following the #lo(value), #hi(value), #ha(value),
// #higher(value), #highera(value), #highest(value), and #highesta(value)
// macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
// document.
static uint16_t applyPPCLo(uint64_t V) { return V; }
static uint16_t applyPPCHi(uint64_t V) { return V >> 16; }
static uint16_t applyPPCHa(uint64_t V) { return (V + 0x8000) >> 16; }
static uint16_t applyPPCHigher(uint64_t V) { return V >> 32; }
static uint16_t applyPPCHighera(uint64_t V) { return (V + 0x8000) >> 32; }
static uint16_t applyPPCHighest(uint64_t V) { return V >> 48; }
static uint16_t applyPPCHighesta(uint64_t V) { return (V + 0x8000) >> 48; }
PPCTargetInfo::PPCTargetInfo() {}
void PPCTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
switch (Type) {
case R_PPC_ADDR16_HA:
write16be(Loc, applyPPCHa(Val));
break;
case R_PPC_ADDR16_LO:
write16be(Loc, applyPPCLo(Val));
break;
case R_PPC_ADDR32:
case R_PPC_REL32:
write32be(Loc, Val);
break;
case R_PPC_REL24:
or32be(Loc, Val & 0x3FFFFFC);
break;
default:
error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
}
}
RelExpr PPCTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
case R_PPC_REL24:
case R_PPC_REL32:
return R_PC;
default:
return R_ABS;
}
}
PPC64TargetInfo::PPC64TargetInfo() {
PltRel = GotRel = R_PPC64_GLOB_DAT;
RelativeRel = R_PPC64_RELATIVE;
GotEntrySize = 8;
GotPltEntrySize = 8;
PltEntrySize = 32;
PltHeaderSize = 0;
// We need 64K pages (at least under glibc/Linux, the loader won't
// set different permissions on a finer granularity than that).
DefaultMaxPageSize = 65536;
// The PPC64 ELF ABI v1 spec, says:
//
// It is normally desirable to put segments with different characteristics
// in separate 256 Mbyte portions of the address space, to give the
// operating system full paging flexibility in the 64-bit address space.
//
// And because the lowest non-zero 256M boundary is 0x10000000, PPC64 linkers
// use 0x10000000 as the starting address.
DefaultImageBase = 0x10000000;
}
static uint64_t PPC64TocOffset = 0x8000;
uint64_t getPPC64TocBase() {
// The TOC consists of sections .got, .toc, .tocbss, .plt in that order. The
// TOC starts where the first of these sections starts. We always create a
// .got when we see a relocation that uses it, so for us the start is always
// the .got.
uint64_t TocVA = InX::Got->getVA();
// Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
// thus permitting a full 64 Kbytes segment. Note that the glibc startup
// code (crt1.o) assumes that you can get from the TOC base to the
// start of the .toc section with only a single (signed) 16-bit relocation.
return TocVA + PPC64TocOffset;
}
RelExpr PPC64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
default:
return R_ABS;
case R_PPC64_TOC16:
case R_PPC64_TOC16_DS:
case R_PPC64_TOC16_HA:
case R_PPC64_TOC16_HI:
case R_PPC64_TOC16_LO:
case R_PPC64_TOC16_LO_DS:
return R_GOTREL;
case R_PPC64_TOC:
return R_PPC_TOC;
case R_PPC64_REL24:
return R_PPC_PLT_OPD;
}
}
void PPC64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
uint64_t Off = GotPltEntryAddr - getPPC64TocBase();
// FIXME: What we should do, in theory, is get the offset of the function
// descriptor in the .opd section, and use that as the offset from %r2 (the
// TOC-base pointer). Instead, we have the GOT-entry offset, and that will
// be a pointer to the function descriptor in the .opd section. Using
// this scheme is simpler, but requires an extra indirection per PLT dispatch.
write32be(Buf, 0xf8410028); // std %r2, 40(%r1)
write32be(Buf + 4, 0x3d620000 | applyPPCHa(Off)); // addis %r11, %r2, X@ha
write32be(Buf + 8, 0xe98b0000 | applyPPCLo(Off)); // ld %r12, X@l(%r11)
write32be(Buf + 12, 0xe96c0000); // ld %r11,0(%r12)
write32be(Buf + 16, 0x7d6903a6); // mtctr %r11
write32be(Buf + 20, 0xe84c0008); // ld %r2,8(%r12)
write32be(Buf + 24, 0xe96c0010); // ld %r11,16(%r12)
write32be(Buf + 28, 0x4e800420); // bctr
}
static std::pair<uint32_t, uint64_t> toAddr16Rel(uint32_t Type, uint64_t Val) {
uint64_t V = Val - PPC64TocOffset;
switch (Type) {
case R_PPC64_TOC16:
return {R_PPC64_ADDR16, V};
case R_PPC64_TOC16_DS:
return {R_PPC64_ADDR16_DS, V};
case R_PPC64_TOC16_HA:
return {R_PPC64_ADDR16_HA, V};
case R_PPC64_TOC16_HI:
return {R_PPC64_ADDR16_HI, V};
case R_PPC64_TOC16_LO:
return {R_PPC64_ADDR16_LO, V};
case R_PPC64_TOC16_LO_DS:
return {R_PPC64_ADDR16_LO_DS, V};
default:
return {Type, Val};
}
}
void PPC64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// For a TOC-relative relocation, proceed in terms of the corresponding
// ADDR16 relocation type.
std::tie(Type, Val) = toAddr16Rel(Type, Val);
switch (Type) {
case R_PPC64_ADDR14: {
checkAlignment<4>(Loc, Val, Type);
// Preserve the AA/LK bits in the branch instruction
uint8_t AALK = Loc[3];
write16be(Loc + 2, (AALK & 3) | (Val & 0xfffc));
break;
}
case R_PPC64_ADDR16:
checkInt<16>(Loc, Val, Type);
write16be(Loc, Val);
break;
case R_PPC64_ADDR16_DS:
checkInt<16>(Loc, Val, Type);
write16be(Loc, (read16be(Loc) & 3) | (Val & ~3));
break;
case R_PPC64_ADDR16_HA:
case R_PPC64_REL16_HA:
write16be(Loc, applyPPCHa(Val));
break;
case R_PPC64_ADDR16_HI:
case R_PPC64_REL16_HI:
write16be(Loc, applyPPCHi(Val));
break;
case R_PPC64_ADDR16_HIGHER:
write16be(Loc, applyPPCHigher(Val));
break;
case R_PPC64_ADDR16_HIGHERA:
write16be(Loc, applyPPCHighera(Val));
break;
case R_PPC64_ADDR16_HIGHEST:
write16be(Loc, applyPPCHighest(Val));
break;
case R_PPC64_ADDR16_HIGHESTA:
write16be(Loc, applyPPCHighesta(Val));
break;
case R_PPC64_ADDR16_LO:
write16be(Loc, applyPPCLo(Val));
break;
case R_PPC64_ADDR16_LO_DS:
case R_PPC64_REL16_LO:
write16be(Loc, (read16be(Loc) & 3) | (applyPPCLo(Val) & ~3));
break;
case R_PPC64_ADDR32:
case R_PPC64_REL32:
checkInt<32>(Loc, Val, Type);
write32be(Loc, Val);
break;
case R_PPC64_ADDR64:
case R_PPC64_REL64:
case R_PPC64_TOC:
write64be(Loc, Val);
break;
case R_PPC64_REL24: {
uint32_t Mask = 0x03FFFFFC;
checkInt<24>(Loc, Val, Type);
write32be(Loc, (read32be(Loc) & ~Mask) | (Val & Mask));
break;
}
default:
error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
}
}
AArch64TargetInfo::AArch64TargetInfo() {
CopyRel = R_AARCH64_COPY;
RelativeRel = R_AARCH64_RELATIVE;
IRelativeRel = R_AARCH64_IRELATIVE;
GotRel = R_AARCH64_GLOB_DAT;
PltRel = R_AARCH64_JUMP_SLOT;
TlsDescRel = R_AARCH64_TLSDESC;
TlsGotRel = R_AARCH64_TLS_TPREL64;
GotEntrySize = 8;
GotPltEntrySize = 8;
PltEntrySize = 16;
PltHeaderSize = 32;
DefaultMaxPageSize = 65536;
// It doesn't seem to be documented anywhere, but tls on aarch64 uses variant
// 1 of the tls structures and the tcb size is 16.
TcbSize = 16;
}
RelExpr AArch64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
default:
return R_ABS;
case R_AARCH64_TLSDESC_ADR_PAGE21:
return R_TLSDESC_PAGE;
case R_AARCH64_TLSDESC_LD64_LO12:
case R_AARCH64_TLSDESC_ADD_LO12:
return R_TLSDESC;
case R_AARCH64_TLSDESC_CALL:
return R_TLSDESC_CALL;
case R_AARCH64_TLSLE_ADD_TPREL_HI12:
case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
return R_TLS;
case R_AARCH64_CALL26:
case R_AARCH64_CONDBR19:
case R_AARCH64_JUMP26:
case R_AARCH64_TSTBR14:
return R_PLT_PC;
case R_AARCH64_PREL16:
case R_AARCH64_PREL32:
case R_AARCH64_PREL64:
case R_AARCH64_ADR_PREL_LO21:
return R_PC;
case R_AARCH64_ADR_PREL_PG_HI21:
return R_PAGE_PC;
case R_AARCH64_LD64_GOT_LO12_NC:
case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
return R_GOT;
case R_AARCH64_ADR_GOT_PAGE:
case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
return R_GOT_PAGE_PC;
case R_AARCH64_NONE:
return R_NONE;
}
}
RelExpr AArch64TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data,
RelExpr Expr) const {
if (Expr == R_RELAX_TLS_GD_TO_IE) {
if (Type == R_AARCH64_TLSDESC_ADR_PAGE21)
return R_RELAX_TLS_GD_TO_IE_PAGE_PC;
return R_RELAX_TLS_GD_TO_IE_ABS;
}
return Expr;
}
bool AArch64TargetInfo::usesOnlyLowPageBits(uint32_t Type) const {
switch (Type) {
default:
return false;
case R_AARCH64_ADD_ABS_LO12_NC:
case R_AARCH64_LD64_GOT_LO12_NC:
case R_AARCH64_LDST128_ABS_LO12_NC:
case R_AARCH64_LDST16_ABS_LO12_NC:
case R_AARCH64_LDST32_ABS_LO12_NC:
case R_AARCH64_LDST64_ABS_LO12_NC:
case R_AARCH64_LDST8_ABS_LO12_NC:
case R_AARCH64_TLSDESC_ADD_LO12:
case R_AARCH64_TLSDESC_LD64_LO12:
case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
return true;
}
}
bool AArch64TargetInfo::isPicRel(uint32_t Type) const {
return Type == R_AARCH64_ABS32 || Type == R_AARCH64_ABS64;
}
void AArch64TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
write64le(Buf, InX::Plt->getVA());
}
// Page(Expr) is the page address of the expression Expr, defined
// as (Expr & ~0xFFF). (This applies even if the machine page size
// supported by the platform has a different value.)
uint64_t getAArch64Page(uint64_t Expr) {
return Expr & (~static_cast<uint64_t>(0xFFF));
}
void AArch64TargetInfo::writePltHeader(uint8_t *Buf) const {
const uint8_t PltData[] = {
0xf0, 0x7b, 0xbf, 0xa9, // stp x16, x30, [sp,#-16]!
0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[2]))
0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[2]))]
0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[2]))
0x20, 0x02, 0x1f, 0xd6, // br x17
0x1f, 0x20, 0x03, 0xd5, // nop
0x1f, 0x20, 0x03, 0xd5, // nop
0x1f, 0x20, 0x03, 0xd5 // nop
};
memcpy(Buf, PltData, sizeof(PltData));
uint64_t Got = InX::GotPlt->getVA();
uint64_t Plt = InX::Plt->getVA();
relocateOne(Buf + 4, R_AARCH64_ADR_PREL_PG_HI21,
getAArch64Page(Got + 16) - getAArch64Page(Plt + 4));
relocateOne(Buf + 8, R_AARCH64_LDST64_ABS_LO12_NC, Got + 16);
relocateOne(Buf + 12, R_AARCH64_ADD_ABS_LO12_NC, Got + 16);
}
void AArch64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const uint8_t Inst[] = {
0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[n]))
0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[n]))]
0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[n]))
0x20, 0x02, 0x1f, 0xd6 // br x17
};
memcpy(Buf, Inst, sizeof(Inst));
relocateOne(Buf, R_AARCH64_ADR_PREL_PG_HI21,
getAArch64Page(GotPltEntryAddr) - getAArch64Page(PltEntryAddr));
relocateOne(Buf + 4, R_AARCH64_LDST64_ABS_LO12_NC, GotPltEntryAddr);
relocateOne(Buf + 8, R_AARCH64_ADD_ABS_LO12_NC, GotPltEntryAddr);
}
static void write32AArch64Addr(uint8_t *L, uint64_t Imm) {
uint32_t ImmLo = (Imm & 0x3) << 29;
uint32_t ImmHi = (Imm & 0x1FFFFC) << 3;
uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3);
write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi);
}
// Return the bits [Start, End] from Val shifted Start bits.
// For instance, getBits(0xF0, 4, 8) returns 0xF.
static uint64_t getBits(uint64_t Val, int Start, int End) {
uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1;
return (Val >> Start) & Mask;
}
// Update the immediate field in a AARCH64 ldr, str, and add instruction.
static void or32AArch64Imm(uint8_t *L, uint64_t Imm) {
or32le(L, (Imm & 0xFFF) << 10);
}
void AArch64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
switch (Type) {
case R_AARCH64_ABS16:
case R_AARCH64_PREL16:
checkIntUInt<16>(Loc, Val, Type);
write16le(Loc, Val);
break;
case R_AARCH64_ABS32:
case R_AARCH64_PREL32:
checkIntUInt<32>(Loc, Val, Type);
write32le(Loc, Val);
break;
case R_AARCH64_ABS64:
case R_AARCH64_GLOB_DAT:
case R_AARCH64_PREL64:
write64le(Loc, Val);
break;
case R_AARCH64_ADD_ABS_LO12_NC:
or32AArch64Imm(Loc, Val);
break;
case R_AARCH64_ADR_GOT_PAGE:
case R_AARCH64_ADR_PREL_PG_HI21:
case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
case R_AARCH64_TLSDESC_ADR_PAGE21:
checkInt<33>(Loc, Val, Type);
write32AArch64Addr(Loc, Val >> 12);
break;
case R_AARCH64_ADR_PREL_LO21:
checkInt<21>(Loc, Val, Type);
write32AArch64Addr(Loc, Val);
break;
case R_AARCH64_CALL26:
case R_AARCH64_JUMP26:
checkInt<28>(Loc, Val, Type);
or32le(Loc, (Val & 0x0FFFFFFC) >> 2);
break;
case R_AARCH64_CONDBR19:
checkInt<21>(Loc, Val, Type);
or32le(Loc, (Val & 0x1FFFFC) << 3);
break;
case R_AARCH64_LD64_GOT_LO12_NC:
case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
case R_AARCH64_TLSDESC_LD64_LO12:
checkAlignment<8>(Loc, Val, Type);
or32le(Loc, (Val & 0xFF8) << 7);
break;
case R_AARCH64_LDST8_ABS_LO12_NC:
or32AArch64Imm(Loc, getBits(Val, 0, 11));
break;
case R_AARCH64_LDST16_ABS_LO12_NC:
or32AArch64Imm(Loc, getBits(Val, 1, 11));
break;
case R_AARCH64_LDST32_ABS_LO12_NC:
or32AArch64Imm(Loc, getBits(Val, 2, 11));
break;
case R_AARCH64_LDST64_ABS_LO12_NC:
or32AArch64Imm(Loc, getBits(Val, 3, 11));
break;
case R_AARCH64_LDST128_ABS_LO12_NC:
or32AArch64Imm(Loc, getBits(Val, 4, 11));
break;
case R_AARCH64_MOVW_UABS_G0_NC:
or32le(Loc, (Val & 0xFFFF) << 5);
break;
case R_AARCH64_MOVW_UABS_G1_NC:
or32le(Loc, (Val & 0xFFFF0000) >> 11);
break;
case R_AARCH64_MOVW_UABS_G2_NC:
or32le(Loc, (Val & 0xFFFF00000000) >> 27);
break;
case R_AARCH64_MOVW_UABS_G3:
or32le(Loc, (Val & 0xFFFF000000000000) >> 43);
break;
case R_AARCH64_TSTBR14:
checkInt<16>(Loc, Val, Type);
or32le(Loc, (Val & 0xFFFC) << 3);
break;
case R_AARCH64_TLSLE_ADD_TPREL_HI12:
checkInt<24>(Loc, Val, Type);
or32AArch64Imm(Loc, Val >> 12);
break;
case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
case R_AARCH64_TLSDESC_ADD_LO12:
or32AArch64Imm(Loc, Val);
break;
default:
error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
}
}
void AArch64TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// TLSDESC Global-Dynamic relocation are in the form:
// adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21]
// ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12]
// add x0, x0, :tlsdesc_los:v [R_AARCH64_TLSDESC_ADD_LO12]
// .tlsdesccall [R_AARCH64_TLSDESC_CALL]
// blr x1
// And it can optimized to:
// movz x0, #0x0, lsl #16
// movk x0, #0x10
// nop
// nop
checkUInt<32>(Loc, Val, Type);
switch (Type) {
case R_AARCH64_TLSDESC_ADD_LO12:
case R_AARCH64_TLSDESC_CALL:
write32le(Loc, 0xd503201f); // nop
return;
case R_AARCH64_TLSDESC_ADR_PAGE21:
write32le(Loc, 0xd2a00000 | (((Val >> 16) & 0xffff) << 5)); // movz
return;
case R_AARCH64_TLSDESC_LD64_LO12:
write32le(Loc, 0xf2800000 | ((Val & 0xffff) << 5)); // movk
return;
default:
llvm_unreachable("unsupported relocation for TLS GD to LE relaxation");
}
}
void AArch64TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
// TLSDESC Global-Dynamic relocation are in the form:
// adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21]
// ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12]
// add x0, x0, :tlsdesc_los:v [R_AARCH64_TLSDESC_ADD_LO12]
// .tlsdesccall [R_AARCH64_TLSDESC_CALL]
// blr x1
// And it can optimized to:
// adrp x0, :gottprel:v
// ldr x0, [x0, :gottprel_lo12:v]
// nop
// nop
switch (Type) {
case R_AARCH64_TLSDESC_ADD_LO12:
case R_AARCH64_TLSDESC_CALL:
write32le(Loc, 0xd503201f); // nop
break;
case R_AARCH64_TLSDESC_ADR_PAGE21:
write32le(Loc, 0x90000000); // adrp
relocateOne(Loc, R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21, Val);
break;
case R_AARCH64_TLSDESC_LD64_LO12:
write32le(Loc, 0xf9400000); // ldr
relocateOne(Loc, R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC, Val);
break;
default:
llvm_unreachable("unsupported relocation for TLS GD to LE relaxation");
}
}
void AArch64TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
checkUInt<32>(Loc, Val, Type);
if (Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21) {
// Generate MOVZ.
uint32_t RegNo = read32le(Loc) & 0x1f;
write32le(Loc, (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5));
return;
}
if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) {
// Generate MOVK.
uint32_t RegNo = read32le(Loc) & 0x1f;
write32le(Loc, (0xf2800000 | RegNo) | ((Val & 0xffff) << 5));
return;
}
llvm_unreachable("invalid relocation for TLS IE to LE relaxation");
}
AMDGPUTargetInfo::AMDGPUTargetInfo() {
RelativeRel = R_AMDGPU_REL64;
GotRel = R_AMDGPU_ABS64;
GotEntrySize = 8;
}
void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
switch (Type) {
case R_AMDGPU_ABS32:
case R_AMDGPU_GOTPCREL:
case R_AMDGPU_GOTPCREL32_LO:
case R_AMDGPU_REL32:
case R_AMDGPU_REL32_LO:
write32le(Loc, Val);
break;
case R_AMDGPU_ABS64:
write64le(Loc, Val);
break;
case R_AMDGPU_GOTPCREL32_HI:
case R_AMDGPU_REL32_HI:
write32le(Loc, Val >> 32);
break;
default:
error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
}
}
RelExpr AMDGPUTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
case R_AMDGPU_ABS32:
case R_AMDGPU_ABS64:
return R_ABS;
case R_AMDGPU_REL32:
case R_AMDGPU_REL32_LO:
case R_AMDGPU_REL32_HI:
return R_PC;
case R_AMDGPU_GOTPCREL:
case R_AMDGPU_GOTPCREL32_LO:
case R_AMDGPU_GOTPCREL32_HI:
return R_GOT_PC;
default:
error(toString(S.File) + ": unknown relocation type: " + toString(Type));
return R_HINT;
}
}
ARMTargetInfo::ARMTargetInfo() {
CopyRel = R_ARM_COPY;
RelativeRel = R_ARM_RELATIVE;
IRelativeRel = R_ARM_IRELATIVE;
GotRel = R_ARM_GLOB_DAT;
PltRel = R_ARM_JUMP_SLOT;
TlsGotRel = R_ARM_TLS_TPOFF32;
TlsModuleIndexRel = R_ARM_TLS_DTPMOD32;
TlsOffsetRel = R_ARM_TLS_DTPOFF32;
GotEntrySize = 4;
GotPltEntrySize = 4;
PltEntrySize = 16;
PltHeaderSize = 20;
// ARM uses Variant 1 TLS
TcbSize = 8;
NeedsThunks = true;
}
RelExpr ARMTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
switch (Type) {
default:
return R_ABS;
case R_ARM_THM_JUMP11:
return R_PC;
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PC24:
case R_ARM_PLT32:
case R_ARM_PREL31:
case R_ARM_THM_JUMP19:
case R_ARM_THM_JUMP24:
case R_ARM_THM_CALL:
return R_PLT_PC;
case R_ARM_GOTOFF32:
// (S + A) - GOT_ORG
return R_GOTREL;
case R_ARM_GOT_BREL:
// GOT(S) + A - GOT_ORG
return R_GOT_OFF;
case R_ARM_GOT_PREL:
case R_ARM_TLS_IE32:
// GOT(S) + A - P
return R_GOT_PC;
case R_ARM_TARGET1:
return Config->Target1Rel ? R_PC : R_ABS;
case R_ARM_TARGET2:
if (Config->Target2 == Target2Policy::Rel)
return R_PC;
if (Config->Target2 == Target2Policy::Abs)
return R_ABS;
return R_GOT_PC;
case R_ARM_TLS_GD32:
return R_TLSGD_PC;
case R_ARM_TLS_LDM32:
return R_TLSLD_PC;
case R_ARM_BASE_PREL:
// B(S) + A - P
// FIXME: currently B(S) assumed to be .got, this may not hold for all
// platforms.
return R_GOTONLY_PC;
case R_ARM_MOVW_PREL_NC:
case R_ARM_MOVT_PREL:
case R_ARM_REL32:
case R_ARM_THM_MOVW_PREL_NC:
case R_ARM_THM_MOVT_PREL:
return R_PC;
case R_ARM_NONE:
return R_NONE;
case R_ARM_TLS_LE32:
return R_TLS;
}
}
bool ARMTargetInfo::isPicRel(uint32_t Type) const {
return (Type == R_ARM_TARGET1 && !Config->Target1Rel) ||
(Type == R_ARM_ABS32);
}
uint32_t ARMTargetInfo::getDynRel(uint32_t Type) const {
if (Type == R_ARM_TARGET1 && !Config->Target1Rel)
return R_ARM_ABS32;
if (Type == R_ARM_ABS32)
return Type;
// Keep it going with a dummy value so that we can find more reloc errors.
return R_ARM_ABS32;
}
void ARMTargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
write32le(Buf, InX::Plt->getVA());
}
void ARMTargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const {
// An ARM entry is the address of the ifunc resolver function.
write32le(Buf, S.getVA());
}
void ARMTargetInfo::writePltHeader(uint8_t *Buf) const {
const uint8_t PltData[] = {
0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]!
0x04, 0xe0, 0x9f, 0xe5, // ldr lr, L2
0x0e, 0xe0, 0x8f, 0xe0, // L1: add lr, pc, lr
0x08, 0xf0, 0xbe, 0xe5, // ldr pc, [lr, #8]
0x00, 0x00, 0x00, 0x00, // L2: .word &(.got.plt) - L1 - 8
};
memcpy(Buf, PltData, sizeof(PltData));
uint64_t GotPlt = InX::GotPlt->getVA();
uint64_t L1 = InX::Plt->getVA() + 8;
write32le(Buf + 16, GotPlt - L1 - 8);
}
void ARMTargetInfo::addPltHeaderSymbols(InputSectionBase *ISD) const {
auto *IS = cast<InputSection>(ISD);
addSyntheticLocal<ELF32LE>("$a", STT_NOTYPE, 0, 0, IS);
addSyntheticLocal<ELF32LE>("$d", STT_NOTYPE, 16, 0, IS);
}
void ARMTargetInfo::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
// FIXME: Using simple code sequence with simple relocations.
// There is a more optimal sequence but it requires support for the group
// relocations. See ELF for the ARM Architecture Appendix A.3
const uint8_t PltData[] = {
0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2
0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc
0x00, 0xf0, 0x9c, 0xe5, // ldr pc, [ip]
0x00, 0x00, 0x00, 0x00, // L2: .word Offset(&(.plt.got) - L1 - 8
};
memcpy(Buf, PltData, sizeof(PltData));
uint64_t L1 = PltEntryAddr + 4;
write32le(Buf + 12, GotPltEntryAddr - L1 - 8);
}
void ARMTargetInfo::addPltSymbols(InputSectionBase *ISD, uint64_t Off) const {
auto *IS = cast<InputSection>(ISD);
addSyntheticLocal<ELF32LE>("$a", STT_NOTYPE, Off, 0, IS);
addSyntheticLocal<ELF32LE>("$d", STT_NOTYPE, Off + 12, 0, IS);
}
bool ARMTargetInfo::needsThunk(RelExpr Expr, uint32_t RelocType,
const InputFile *File,
const SymbolBody &S) const {
// If S is an undefined weak symbol in an executable we don't need a Thunk.
// In a DSO calls to undefined symbols, including weak ones get PLT entries
// which may need a thunk.
if (S.isUndefined() && !S.isLocal() && S.symbol()->isWeak() &&
!Config->Shared)
return false;
// A state change from ARM to Thumb and vice versa must go through an
// interworking thunk if the relocation type is not R_ARM_CALL or
// R_ARM_THM_CALL.
switch (RelocType) {
case R_ARM_PC24:
case R_ARM_PLT32:
case R_ARM_JUMP24:
// Source is ARM, all PLT entries are ARM so no interworking required.
// Otherwise we need to interwork if Symbol has bit 0 set (Thumb).
if (Expr == R_PC && ((S.getVA() & 1) == 1))
return true;
break;
case R_ARM_THM_JUMP19:
case R_ARM_THM_JUMP24:
// Source is Thumb, all PLT entries are ARM so interworking is required.
// Otherwise we need to interwork if Symbol has bit 0 clear (ARM).
if (Expr == R_PLT_PC || ((S.getVA() & 1) == 0))
return true;
break;
}
return false;
}
void ARMTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
switch (Type) {
case R_ARM_ABS32:
case R_ARM_BASE_PREL:
case R_ARM_GLOB_DAT:
case R_ARM_GOTOFF32:
case R_ARM_GOT_BREL:
case R_ARM_GOT_PREL:
case R_ARM_REL32:
case R_ARM_RELATIVE:
case R_ARM_TARGET1:
case R_ARM_TARGET2:
case R_ARM_TLS_GD32:
case R_ARM_TLS_IE32:
case R_ARM_TLS_LDM32:
case R_ARM_TLS_LDO32:
case R_ARM_TLS_LE32:
case R_ARM_TLS_TPOFF32:
case R_ARM_TLS_DTPOFF32:
write32le(Loc, Val);
break;
case R_ARM_TLS_DTPMOD32:
write32le(Loc, 1);
break;
case R_ARM_PREL31:
checkInt<31>(Loc, Val, Type);
write32le(Loc, (read32le(Loc) & 0x80000000) | (Val & ~0x80000000));
break;
case R_ARM_CALL:
// R_ARM_CALL is used for BL and BLX instructions, depending on the
// value of bit 0 of Val, we must select a BL or BLX instruction
if (Val & 1) {
// If bit 0 of Val is 1 the target is Thumb, we must select a BLX.
// The BLX encoding is 0xfa:H:imm24 where Val = imm24:H:'1'
checkInt<26>(Loc, Val, Type);
write32le(Loc, 0xfa000000 | // opcode
((Val & 2) << 23) | // H
((Val >> 2) & 0x00ffffff)); // imm24
break;
}
if ((read32le(Loc) & 0xfe000000) == 0xfa000000)
// BLX (always unconditional) instruction to an ARM Target, select an
// unconditional BL.
write32le(Loc, 0xeb000000 | (read32le(Loc) & 0x00ffffff));
// fall through as BL encoding is shared with B
LLVM_FALLTHROUGH;
case R_ARM_JUMP24:
case R_ARM_PC24:
case R_ARM_PLT32:
checkInt<26>(Loc, Val, Type);
write32le(Loc, (read32le(Loc) & ~0x00ffffff) | ((Val >> 2) & 0x00ffffff));
break;
case R_ARM_THM_JUMP11:
checkInt<12>(Loc, Val, Type);
write16le(Loc, (read32le(Loc) & 0xf800) | ((Val >> 1) & 0x07ff));
break;
case R_ARM_THM_JUMP19:
// Encoding T3: Val = S:J2:J1:imm6:imm11:0
checkInt<21>(Loc, Val, Type);
write16le(Loc,
(read16le(Loc) & 0xfbc0) | // opcode cond
((Val >> 10) & 0x0400) | // S
((Val >> 12) & 0x003f)); // imm6
write16le(Loc + 2,
0x8000 | // opcode
((Val >> 8) & 0x0800) | // J2
((Val >> 5) & 0x2000) | // J1
((Val >> 1) & 0x07ff)); // imm11
break;
case R_ARM_THM_CALL:
// R_ARM_THM_CALL is used for BL and BLX instructions, depending on the
// value of bit 0 of Val, we must select a BL or BLX instruction
if ((Val & 1) == 0) {
// Ensure BLX destination is 4-byte aligned. As BLX instruction may
// only be two byte aligned. This must be done before overflow check
Val = alignTo(Val, 4);
}
// Bit 12 is 0 for BLX, 1 for BL
write16le(Loc + 2, (read16le(Loc + 2) & ~0x1000) | (Val & 1) << 12);
// Fall through as rest of encoding is the same as B.W
LLVM_FALLTHROUGH;
case R_ARM_THM_JUMP24:
// Encoding B T4, BL T1, BLX T2: Val = S:I1:I2:imm10:imm11:0
// FIXME: Use of I1 and I2 require v6T2ops
checkInt<25>(Loc, Val, Type);
write16le(Loc,
0xf000 | // opcode
((Val >> 14) & 0x0400) | // S
((Val >> 12) & 0x03ff)); // imm10
write16le(Loc + 2,
(read16le(Loc + 2) & 0xd000) | // opcode
(((~(Val >> 10)) ^ (Val >> 11)) & 0x2000) | // J1
(((~(Val >> 11)) ^ (Val >> 13)) & 0x0800) | // J2
((Val >> 1) & 0x07ff)); // imm11
break;
case R_ARM_MOVW_ABS_NC:
case R_ARM_MOVW_PREL_NC:
write32le(Loc, (read32le(Loc) & ~0x000f0fff) | ((Val & 0xf000) << 4) |
(Val & 0x0fff));
break;
case R_ARM_MOVT_ABS:
case R_ARM_MOVT_PREL:
checkInt<32>(Loc, Val, Type);
write32le(Loc, (read32le(Loc) & ~0x000f0fff) |
(((Val >> 16) & 0xf000) << 4) | ((Val >> 16) & 0xfff));
break;
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVT_PREL:
// Encoding T1: A = imm4:i:imm3:imm8
checkInt<32>(Loc, Val, Type);
write16le(Loc,
0xf2c0 | // opcode
((Val >> 17) & 0x0400) | // i
((Val >> 28) & 0x000f)); // imm4
write16le(Loc + 2,
(read16le(Loc + 2) & 0x8f00) | // opcode
((Val >> 12) & 0x7000) | // imm3
((Val >> 16) & 0x00ff)); // imm8
break;
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_THM_MOVW_PREL_NC:
// Encoding T3: A = imm4:i:imm3:imm8
write16le(Loc,
0xf240 | // opcode
((Val >> 1) & 0x0400) | // i
((Val >> 12) & 0x000f)); // imm4
write16le(Loc + 2,
(read16le(Loc + 2) & 0x8f00) | // opcode
((Val << 4) & 0x7000) | // imm3
(Val & 0x00ff)); // imm8
break;
default:
error(getErrorLocation(Loc) + "unrecognized reloc " + Twine(Type));
}
}
int64_t ARMTargetInfo::getImplicitAddend(const uint8_t *Buf,
uint32_t Type) const {
switch (Type) {
default:
return 0;
case R_ARM_ABS32:
case R_ARM_BASE_PREL:
case R_ARM_GOTOFF32:
case R_ARM_GOT_BREL:
case R_ARM_GOT_PREL:
case R_ARM_REL32:
case R_ARM_TARGET1:
case R_ARM_TARGET2:
case R_ARM_TLS_GD32:
case R_ARM_TLS_LDM32:
case R_ARM_TLS_LDO32:
case R_ARM_TLS_IE32:
case R_ARM_TLS_LE32:
return SignExtend64<32>(read32le(Buf));
case R_ARM_PREL31:
return SignExtend64<31>(read32le(Buf));
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PC24:
case R_ARM_PLT32:
return SignExtend64<26>(read32le(Buf) << 2);
case R_ARM_THM_JUMP11:
return SignExtend64<12>(read16le(Buf) << 1);
case R_ARM_THM_JUMP19: {
// Encoding T3: A = S:J2:J1:imm10:imm6:0
uint16_t Hi = read16le(Buf);
uint16_t Lo = read16le(Buf + 2);
return SignExtend64<20>(((Hi & 0x0400) << 10) | // S
((Lo & 0x0800) << 8) | // J2
((Lo & 0x2000) << 5) | // J1
((Hi & 0x003f) << 12) | // imm6
((Lo & 0x07ff) << 1)); // imm11:0
}
case R_ARM_THM_CALL:
case R_ARM_THM_JUMP24: {
// Encoding B T4, BL T1, BLX T2: A = S:I1:I2:imm10:imm11:0
// I1 = NOT(J1 EOR S), I2 = NOT(J2 EOR S)
// FIXME: I1 and I2 require v6T2ops
uint16_t Hi = read16le(Buf);
uint16_t Lo = read16le(Buf + 2);
return SignExtend64<24>(((Hi & 0x0400) << 14) | // S
(~((Lo ^ (Hi << 3)) << 10) & 0x00800000) | // I1
(~((Lo ^ (Hi << 1)) << 11) & 0x00400000) | // I2
((Hi & 0x003ff) << 12) | // imm0
((Lo & 0x007ff) << 1)); // imm11:0
}
// ELF for the ARM Architecture 4.6.1.1 the implicit addend for MOVW and
// MOVT is in the range -32768 <= A < 32768
case R_ARM_MOVW_ABS_NC:
case R_ARM_MOVT_ABS:
case R_ARM_MOVW_PREL_NC:
case R_ARM_MOVT_PREL: {
uint64_t Val = read32le(Buf) & 0x000f0fff;
return SignExtend64<16>(((Val & 0x000f0000) >> 4) | (Val & 0x00fff));
}
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVW_PREL_NC:
case R_ARM_THM_MOVT_PREL: {
// Encoding T3: A = imm4:i:imm3:imm8
uint16_t Hi = read16le(Buf);
uint16_t Lo = read16le(Buf + 2);
return SignExtend64<16>(((Hi & 0x000f) << 12) | // imm4
((Hi & 0x0400) << 1) | // i
((Lo & 0x7000) >> 4) | // imm3
(Lo & 0x00ff)); // imm8
}
}
}
template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() {
GotPltHeaderEntriesNum = 2;
DefaultMaxPageSize = 65536;
GotEntrySize = sizeof(typename ELFT::uint);
GotPltEntrySize = sizeof(typename ELFT::uint);
PltEntrySize = 16;
PltHeaderSize = 32;
CopyRel = R_MIPS_COPY;
PltRel = R_MIPS_JUMP_SLOT;
NeedsThunks = true;
if (ELFT::Is64Bits) {
RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32;
TlsGotRel = R_MIPS_TLS_TPREL64;
TlsModuleIndexRel = R_MIPS_TLS_DTPMOD64;
TlsOffsetRel = R_MIPS_TLS_DTPREL64;
} else {
RelativeRel = R_MIPS_REL32;
TlsGotRel = R_MIPS_TLS_TPREL32;
TlsModuleIndexRel = R_MIPS_TLS_DTPMOD32;
TlsOffsetRel = R_MIPS_TLS_DTPREL32;
}
}
template <class ELFT>
RelExpr MipsTargetInfo<ELFT>::getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const {
// See comment in the calculateMipsRelChain.
if (ELFT::Is64Bits || Config->MipsN32Abi)
Type &= 0xff;
switch (Type) {
default:
return R_ABS;
case R_MIPS_JALR:
return R_HINT;
case R_MIPS_GPREL16:
case R_MIPS_GPREL32:
return R_MIPS_GOTREL;
case R_MIPS_26:
return R_PLT;
case R_MIPS_HI16:
case R_MIPS_LO16:
// R_MIPS_HI16/R_MIPS_LO16 relocations against _gp_disp calculate
// offset between start of function and 'gp' value which by default
// equal to the start of .got section. In that case we consider these
// relocations as relative.
if (&S == ElfSym::MipsGpDisp)
return R_MIPS_GOT_GP_PC;
if (&S == ElfSym::MipsLocalGp)
return R_MIPS_GOT_GP;
// fallthrough
case R_MIPS_GOT_OFST:
return R_ABS;
case R_MIPS_PC32:
case R_MIPS_PC16:
case R_MIPS_PC19_S2:
case R_MIPS_PC21_S2:
case R_MIPS_PC26_S2:
case R_MIPS_PCHI16:
case R_MIPS_PCLO16:
return R_PC;
case R_MIPS_GOT16:
if (S.isLocal())
return R_MIPS_GOT_LOCAL_PAGE;
// fallthrough
case R_MIPS_CALL16:
case R_MIPS_GOT_DISP:
case R_MIPS_TLS_GOTTPREL:
return R_MIPS_GOT_OFF;
case R_MIPS_CALL_HI16:
case R_MIPS_CALL_LO16:
case R_MIPS_GOT_HI16:
case R_MIPS_GOT_LO16:
return R_MIPS_GOT_OFF32;
case R_MIPS_GOT_PAGE:
return R_MIPS_GOT_LOCAL_PAGE;
case R_MIPS_TLS_GD:
return R_MIPS_TLSGD;
case R_MIPS_TLS_LDM:
return R_MIPS_TLSLD;
}
}
template <class ELFT> bool MipsTargetInfo<ELFT>::isPicRel(uint32_t Type) const {
return Type == R_MIPS_32 || Type == R_MIPS_64;
}
template <class ELFT>
uint32_t MipsTargetInfo<ELFT>::getDynRel(uint32_t Type) const {
return RelativeRel;
}
template <class ELFT>
void MipsTargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
write32<ELFT::TargetEndianness>(Buf, InX::Plt->getVA());
}
template <endianness E, uint8_t BSIZE, uint8_t SHIFT>
static int64_t getPcRelocAddend(const uint8_t *Loc) {
uint32_t Instr = read32<E>(Loc);
uint32_t Mask = 0xffffffff >> (32 - BSIZE);
return SignExtend64<BSIZE + SHIFT>((Instr & Mask) << SHIFT);
}
template <endianness E, uint8_t BSIZE, uint8_t SHIFT>
static void applyMipsPcReloc(uint8_t *Loc, uint32_t Type, uint64_t V) {
uint32_t Mask = 0xffffffff >> (32 - BSIZE);
uint32_t Instr = read32<E>(Loc);
if (SHIFT > 0)
checkAlignment<(1 << SHIFT)>(Loc, V, Type);
checkInt<BSIZE + SHIFT>(Loc, V, Type);
write32<E>(Loc, (Instr & ~Mask) | ((V >> SHIFT) & Mask));
}
template <endianness E> static void writeMipsHi16(uint8_t *Loc, uint64_t V) {
uint32_t Instr = read32<E>(Loc);
uint16_t Res = ((V + 0x8000) >> 16) & 0xffff;
write32<E>(Loc, (Instr & 0xffff0000) | Res);
}
template <endianness E> static void writeMipsHigher(uint8_t *Loc, uint64_t V) {
uint32_t Instr = read32<E>(Loc);
uint16_t Res = ((V + 0x80008000) >> 32) & 0xffff;
write32<E>(Loc, (Instr & 0xffff0000) | Res);
}
template <endianness E> static void writeMipsHighest(uint8_t *Loc, uint64_t V) {
uint32_t Instr = read32<E>(Loc);
uint16_t Res = ((V + 0x800080008000) >> 48) & 0xffff;
write32<E>(Loc, (Instr & 0xffff0000) | Res);
}
template <endianness E> static void writeMipsLo16(uint8_t *Loc, uint64_t V) {
uint32_t Instr = read32<E>(Loc);
write32<E>(Loc, (Instr & 0xffff0000) | (V & 0xffff));
}
template <class ELFT> static bool isMipsR6() {
const auto &FirstObj = cast<ELFFileBase<ELFT>>(*Config->FirstElf);
uint32_t Arch = FirstObj.getObj().getHeader()->e_flags & EF_MIPS_ARCH;
return Arch == EF_MIPS_ARCH_32R6 || Arch == EF_MIPS_ARCH_64R6;
}
template <class ELFT>
void MipsTargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const {
const endianness E = ELFT::TargetEndianness;
if (Config->MipsN32Abi) {
write32<E>(Buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0])
write32<E>(Buf + 4, 0x8dd90000); // lw $25, %lo(&GOTPLT[0])($14)
write32<E>(Buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0])
write32<E>(Buf + 12, 0x030ec023); // subu $24, $24, $14
} else {
write32<E>(Buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0])
write32<E>(Buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28)
write32<E>(Buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0])
write32<E>(Buf + 12, 0x031cc023); // subu $24, $24, $28
}
write32<E>(Buf + 16, 0x03e07825); // move $15, $31
write32<E>(Buf + 20, 0x0018c082); // srl $24, $24, 2
write32<E>(Buf + 24, 0x0320f809); // jalr $25
write32<E>(Buf + 28, 0x2718fffe); // subu $24, $24, 2
uint64_t GotPlt = InX::GotPlt->getVA();
writeMipsHi16<E>(Buf, GotPlt);
writeMipsLo16<E>(Buf + 4, GotPlt);
writeMipsLo16<E>(Buf + 8, GotPlt);
}
template <class ELFT>
void MipsTargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const endianness E = ELFT::TargetEndianness;
write32<E>(Buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry)
write32<E>(Buf + 4, 0x8df90000); // l[wd] $25, %lo(.got.plt entry)($15)
// jr $25
write32<E>(Buf + 8, isMipsR6<ELFT>() ? 0x03200009 : 0x03200008);
write32<E>(Buf + 12, 0x25f80000); // addiu $24, $15, %lo(.got.plt entry)
writeMipsHi16<E>(Buf, GotPltEntryAddr);
writeMipsLo16<E>(Buf + 4, GotPltEntryAddr);
writeMipsLo16<E>(Buf + 12, GotPltEntryAddr);
}
template <class ELFT>
bool MipsTargetInfo<ELFT>::needsThunk(RelExpr Expr, uint32_t Type,
const InputFile *File,
const SymbolBody &S) const {
// Any MIPS PIC code function is invoked with its address in register $t9.
// So if we have a branch instruction from non-PIC code to the PIC one
// we cannot make the jump directly and need to create a small stubs
// to save the target function address.
// See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
if (Type != R_MIPS_26)
return false;
auto *F = dyn_cast_or_null<ELFFileBase<ELFT>>(File);
if (!F)
return false;
// If current file has PIC code, LA25 stub is not required.
if (F->getObj().getHeader()->e_flags & EF_MIPS_PIC)
return false;
auto *D = dyn_cast<DefinedRegular>(&S);
// LA25 is required if target file has PIC code
// or target symbol is a PIC symbol.
return D && D->isMipsPIC<ELFT>();
}
template <class ELFT>
int64_t MipsTargetInfo<ELFT>::getImplicitAddend(const uint8_t *Buf,
uint32_t Type) const {
const endianness E = ELFT::TargetEndianness;
switch (Type) {
default:
return 0;
case R_MIPS_32:
case R_MIPS_GPREL32:
case R_MIPS_TLS_DTPREL32:
case R_MIPS_TLS_TPREL32:
return SignExtend64<32>(read32<E>(Buf));
case R_MIPS_26:
// FIXME (simon): If the relocation target symbol is not a PLT entry
// we should use another expression for calculation:
// ((A << 2) | (P & 0xf0000000)) >> 2
return SignExtend64<28>((read32<E>(Buf) & 0x3ffffff) << 2);
case R_MIPS_GPREL16:
case R_MIPS_LO16:
case R_MIPS_PCLO16:
case R_MIPS_TLS_DTPREL_HI16:
case R_MIPS_TLS_DTPREL_LO16:
case R_MIPS_TLS_TPREL_HI16:
case R_MIPS_TLS_TPREL_LO16:
return SignExtend64<16>(read32<E>(Buf));
case R_MIPS_PC16:
return getPcRelocAddend<E, 16, 2>(Buf);
case R_MIPS_PC19_S2:
return getPcRelocAddend<E, 19, 2>(Buf);
case R_MIPS_PC21_S2:
return getPcRelocAddend<E, 21, 2>(Buf);
case R_MIPS_PC26_S2:
return getPcRelocAddend<E, 26, 2>(Buf);
case R_MIPS_PC32:
return getPcRelocAddend<E, 32, 0>(Buf);
}
}
static std::pair<uint32_t, uint64_t>
calculateMipsRelChain(uint8_t *Loc, uint32_t Type, uint64_t Val) {
// MIPS N64 ABI packs multiple relocations into the single relocation
// record. In general, all up to three relocations can have arbitrary
// types. In fact, Clang and GCC uses only a few combinations. For now,
// we support two of them. That is allow to pass at least all LLVM
// test suite cases.
// <any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16
// <any relocation> / R_MIPS_64 / R_MIPS_NONE
// The first relocation is a 'real' relocation which is calculated
// using the corresponding symbol's value. The second and the third
// relocations used to modify result of the first one: extend it to
// 64-bit, extract high or low part etc. For details, see part 2.9 Relocation
// at the https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf
uint32_t Type2 = (Type >> 8) & 0xff;
uint32_t Type3 = (Type >> 16) & 0xff;
if (Type2 == R_MIPS_NONE && Type3 == R_MIPS_NONE)
return std::make_pair(Type, Val);
if (Type2 == R_MIPS_64 && Type3 == R_MIPS_NONE)
return std::make_pair(Type2, Val);
if (Type2 == R_MIPS_SUB && (Type3 == R_MIPS_HI16 || Type3 == R_MIPS_LO16))
return std::make_pair(Type3, -Val);
error(getErrorLocation(Loc) + "unsupported relocations combination " +
Twine(Type));
return std::make_pair(Type & 0xff, Val);
}
template <class ELFT>
void MipsTargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
const endianness E = ELFT::TargetEndianness;
// Thread pointer and DRP offsets from the start of TLS data area.
// https://www.linux-mips.org/wiki/NPTL
if (Type == R_MIPS_TLS_DTPREL_HI16 || Type == R_MIPS_TLS_DTPREL_LO16 ||
Type == R_MIPS_TLS_DTPREL32 || Type == R_MIPS_TLS_DTPREL64)
Val -= 0x8000;
else if (Type == R_MIPS_TLS_TPREL_HI16 || Type == R_MIPS_TLS_TPREL_LO16 ||
Type == R_MIPS_TLS_TPREL32 || Type == R_MIPS_TLS_TPREL64)
Val -= 0x7000;
if (ELFT::Is64Bits || Config->MipsN32Abi)
std::tie(Type, Val) = calculateMipsRelChain(Loc, Type, Val);
switch (Type) {
case R_MIPS_32:
case R_MIPS_GPREL32:
case R_MIPS_TLS_DTPREL32:
case R_MIPS_TLS_TPREL32:
write32<E>(Loc, Val);
break;
case R_MIPS_64:
case R_MIPS_TLS_DTPREL64:
case R_MIPS_TLS_TPREL64:
write64<E>(Loc, Val);
break;
case R_MIPS_26:
write32<E>(Loc, (read32<E>(Loc) & ~0x3ffffff) | ((Val >> 2) & 0x3ffffff));
break;
case R_MIPS_GOT16:
// The R_MIPS_GOT16 relocation's value in "relocatable" linking mode
// is updated addend (not a GOT index). In that case write high 16 bits
// to store a correct addend value.
if (Config->Relocatable)
writeMipsHi16<E>(Loc, Val);
else {
checkInt<16>(Loc, Val, Type);
writeMipsLo16<E>(Loc, Val);
}
break;
case R_MIPS_GOT_DISP:
case R_MIPS_GOT_PAGE:
case R_MIPS_GPREL16:
case R_MIPS_TLS_GD:
case R_MIPS_TLS_LDM:
checkInt<16>(Loc, Val, Type);
// fallthrough
case R_MIPS_CALL16:
case R_MIPS_CALL_LO16:
case R_MIPS_GOT_LO16:
case R_MIPS_GOT_OFST:
case R_MIPS_LO16:
case R_MIPS_PCLO16:
case R_MIPS_TLS_DTPREL_LO16:
case R_MIPS_TLS_GOTTPREL:
case R_MIPS_TLS_TPREL_LO16:
writeMipsLo16<E>(Loc, Val);
break;
case R_MIPS_CALL_HI16:
case R_MIPS_GOT_HI16:
case R_MIPS_HI16:
case R_MIPS_PCHI16:
case R_MIPS_TLS_DTPREL_HI16:
case R_MIPS_TLS_TPREL_HI16:
writeMipsHi16<E>(Loc, Val);
break;
case R_MIPS_HIGHER:
writeMipsHigher<E>(Loc, Val);
break;
case R_MIPS_HIGHEST:
writeMipsHighest<E>(Loc, Val);
break;
case R_MIPS_JALR:
// Ignore this optimization relocation for now
break;
case R_MIPS_PC16:
applyMipsPcReloc<E, 16, 2>(Loc, Type, Val);
break;
case R_MIPS_PC19_S2:
applyMipsPcReloc<E, 19, 2>(Loc, Type, Val);
break;
case R_MIPS_PC21_S2:
applyMipsPcReloc<E, 21, 2>(Loc, Type, Val);