maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/lld/ELF/Arch/Mips.cpp

798 lines
26 KiB
C++
Raw Blame History

//===- MIPS.cpp -----------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "InputFiles.h"
#include "OutputSections.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "Target.h"
#include "Thunks.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;
namespace {
template <class ELFT> class MIPS final : public TargetInfo {
public:
MIPS();
uint32_t calcEFlags() const override;
RelExpr getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const override;
int64_t getImplicitAddend(const uint8_t *buf, RelType type) const override;
RelType getDynRel(RelType type) const override;
void writeGotPlt(uint8_t *buf, const Symbol &s) const override;
void writePltHeader(uint8_t *buf) const override;
void writePlt(uint8_t *buf, const Symbol &sym,
uint64_t pltEntryAddr) const override;
bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
uint64_t branchAddr, const Symbol &s,
int64_t a) const override;
void relocate(uint8_t *loc, const Relocation &rel,
uint64_t val) const override;
bool usesOnlyLowPageBits(RelType type) const override;
};
} // namespace
template <class ELFT> MIPS<ELFT>::MIPS() {
gotPltHeaderEntriesNum = 2;
defaultMaxPageSize = 65536;
gotBaseSymInGotPlt = false;
pltEntrySize = 16;
pltHeaderSize = 32;
copyRel = R_MIPS_COPY;
noneRel = R_MIPS_NONE;
pltRel = R_MIPS_JUMP_SLOT;
needsThunks = true;
// Set `sigrie 1` as a trap instruction.
write32(trapInstr.data(), 0x04170001);
if (ELFT::Is64Bits) {
relativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32;
symbolicRel = R_MIPS_64;
tlsGotRel = R_MIPS_TLS_TPREL64;
tlsModuleIndexRel = R_MIPS_TLS_DTPMOD64;
tlsOffsetRel = R_MIPS_TLS_DTPREL64;
} else {
relativeRel = R_MIPS_REL32;
symbolicRel = R_MIPS_32;
tlsGotRel = R_MIPS_TLS_TPREL32;
tlsModuleIndexRel = R_MIPS_TLS_DTPMOD32;
tlsOffsetRel = R_MIPS_TLS_DTPREL32;
}
}
template <class ELFT> uint32_t MIPS<ELFT>::calcEFlags() const {
return calcMipsEFlags<ELFT>();
}
template <class ELFT>
RelExpr MIPS<ELFT>::getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const {
// See comment in the calculateMipsRelChain.
if (ELFT::Is64Bits || config->mipsN32Abi)
type &= 0xff;
switch (type) {
case R_MIPS_JALR:
// Older versions of clang would erroneously emit this relocation not only
// against functions (loaded from the GOT) but also against data symbols
// (e.g. a table of function pointers). When we encounter this, ignore the
// relocation and emit a warning instead.
if (!s.isFunc() && s.type != STT_NOTYPE) {
warn(getErrorLocation(loc) +
"found R_MIPS_JALR relocation against non-function symbol " +
toString(s) + ". This is invalid and most likely a compiler bug.");
return R_NONE;
}
// If the target symbol is not preemptible and is not microMIPS,
// it might be possible to replace jalr/jr instruction by bal/b.
// It depends on the target symbol's offset.
if (!s.isPreemptible && !(s.getVA() & 0x1))
return R_PC;
return R_NONE;
case R_MICROMIPS_JALR:
return R_NONE;
case R_MIPS_GPREL16:
case R_MIPS_GPREL32:
case R_MICROMIPS_GPREL16:
case R_MICROMIPS_GPREL7_S2:
return R_MIPS_GOTREL;
case R_MIPS_26:
case R_MICROMIPS_26_S1:
return R_PLT;
case R_MICROMIPS_PC26_S1:
return R_PLT_PC;
case R_MIPS_HI16:
case R_MIPS_LO16:
case R_MIPS_HIGHER:
case R_MIPS_HIGHEST:
case R_MICROMIPS_HI16:
case R_MICROMIPS_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;
LLVM_FALLTHROUGH;
case R_MIPS_32:
case R_MIPS_64:
case R_MIPS_GOT_OFST:
case R_MIPS_SUB:
case R_MIPS_TLS_DTPREL_HI16:
case R_MIPS_TLS_DTPREL_LO16:
case R_MIPS_TLS_DTPREL32:
case R_MIPS_TLS_DTPREL64:
case R_MICROMIPS_TLS_DTPREL_HI16:
case R_MICROMIPS_TLS_DTPREL_LO16:
return R_ABS;
case R_MIPS_TLS_TPREL_HI16:
case R_MIPS_TLS_TPREL_LO16:
case R_MIPS_TLS_TPREL32:
case R_MIPS_TLS_TPREL64:
case R_MICROMIPS_TLS_TPREL_HI16:
case R_MICROMIPS_TLS_TPREL_LO16:
return R_TPREL;
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:
case R_MICROMIPS_PC7_S1:
case R_MICROMIPS_PC10_S1:
case R_MICROMIPS_PC16_S1:
case R_MICROMIPS_PC18_S3:
case R_MICROMIPS_PC19_S2:
case R_MICROMIPS_PC23_S2:
case R_MICROMIPS_PC21_S1:
return R_PC;
case R_MIPS_GOT16:
case R_MICROMIPS_GOT16:
if (s.isLocal())
return R_MIPS_GOT_LOCAL_PAGE;
LLVM_FALLTHROUGH;
case R_MIPS_CALL16:
case R_MIPS_GOT_DISP:
case R_MIPS_TLS_GOTTPREL:
case R_MICROMIPS_CALL16:
case R_MICROMIPS_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:
case R_MICROMIPS_CALL_HI16:
case R_MICROMIPS_CALL_LO16:
case R_MICROMIPS_GOT_HI16:
case R_MICROMIPS_GOT_LO16:
return R_MIPS_GOT_OFF32;
case R_MIPS_GOT_PAGE:
return R_MIPS_GOT_LOCAL_PAGE;
case R_MIPS_TLS_GD:
case R_MICROMIPS_TLS_GD:
return R_MIPS_TLSGD;
case R_MIPS_TLS_LDM:
case R_MICROMIPS_TLS_LDM:
return R_MIPS_TLSLD;
case R_MIPS_NONE:
return R_NONE;
default:
error(getErrorLocation(loc) + "unknown relocation (" + Twine(type) +
") against symbol " + toString(s));
return R_NONE;
}
}
template <class ELFT> RelType MIPS<ELFT>::getDynRel(RelType type) const {
if (type == symbolicRel)
return type;
return R_MIPS_NONE;
}
template <class ELFT>
void MIPS<ELFT>::writeGotPlt(uint8_t *buf, const Symbol &) const {
uint64_t va = in.plt->getVA();
if (isMicroMips())
va |= 1;
write32(buf, va);
}
template <endianness E> static uint32_t readShuffle(const uint8_t *loc) {
// The major opcode of a microMIPS instruction needs to appear
// in the first 16-bit word (lowest address) for efficient hardware
// decode so that it knows if the instruction is 16-bit or 32-bit
// as early as possible. To do so, little-endian binaries keep 16-bit
// words in a big-endian order. That is why we have to swap these
// words to get a correct value.
uint32_t v = read32(loc);
if (E == support::little)
return (v << 16) | (v >> 16);
return v;
}
static void writeValue(uint8_t *loc, uint64_t v, uint8_t bitsSize,
uint8_t shift) {
uint32_t instr = read32(loc);
uint32_t mask = 0xffffffff >> (32 - bitsSize);
uint32_t data = (instr & ~mask) | ((v >> shift) & mask);
write32(loc, data);
}
template <endianness E>
static void writeShuffleValue(uint8_t *loc, uint64_t v, uint8_t bitsSize,
uint8_t shift) {
// See comments in readShuffle for purpose of this code.
uint16_t *words = (uint16_t *)loc;
if (E == support::little)
std::swap(words[0], words[1]);
writeValue(loc, v, bitsSize, shift);
if (E == support::little)
std::swap(words[0], words[1]);
}
template <endianness E>
static void writeMicroRelocation16(uint8_t *loc, uint64_t v, uint8_t bitsSize,
uint8_t shift) {
uint16_t instr = read16(loc);
uint16_t mask = 0xffff >> (16 - bitsSize);
uint16_t data = (instr & ~mask) | ((v >> shift) & mask);
write16(loc, data);
}
template <class ELFT> void MIPS<ELFT>::writePltHeader(uint8_t *buf) const {
if (isMicroMips()) {
uint64_t gotPlt = in.gotPlt->getVA();
uint64_t plt = in.plt->getVA();
// Overwrite trap instructions written by Writer::writeTrapInstr.
memset(buf, 0, pltHeaderSize);
write16(buf, isMipsR6() ? 0x7860 : 0x7980); // addiupc v1, (GOTPLT) - .
write16(buf + 4, 0xff23); // lw $25, 0($3)
write16(buf + 8, 0x0535); // subu16 $2, $2, $3
write16(buf + 10, 0x2525); // srl16 $2, $2, 2
write16(buf + 12, 0x3302); // addiu $24, $2, -2
write16(buf + 14, 0xfffe);
write16(buf + 16, 0x0dff); // move $15, $31
if (isMipsR6()) {
write16(buf + 18, 0x0f83); // move $28, $3
write16(buf + 20, 0x472b); // jalrc $25
write16(buf + 22, 0x0c00); // nop
relocateNoSym(buf, R_MICROMIPS_PC19_S2, gotPlt - plt);
} else {
write16(buf + 18, 0x45f9); // jalrc $25
write16(buf + 20, 0x0f83); // move $28, $3
write16(buf + 22, 0x0c00); // nop
relocateNoSym(buf, R_MICROMIPS_PC23_S2, gotPlt - plt);
}
return;
}
if (config->mipsN32Abi) {
write32(buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0])
write32(buf + 4, 0x8dd90000); // lw $25, %lo(&GOTPLT[0])($14)
write32(buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0])
write32(buf + 12, 0x030ec023); // subu $24, $24, $14
write32(buf + 16, 0x03e07825); // move $15, $31
write32(buf + 20, 0x0018c082); // srl $24, $24, 2
} else if (ELFT::Is64Bits) {
write32(buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0])
write32(buf + 4, 0xddd90000); // ld $25, %lo(&GOTPLT[0])($14)
write32(buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0])
write32(buf + 12, 0x030ec023); // subu $24, $24, $14
write32(buf + 16, 0x03e07825); // move $15, $31
write32(buf + 20, 0x0018c0c2); // srl $24, $24, 3
} else {
write32(buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0])
write32(buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28)
write32(buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0])
write32(buf + 12, 0x031cc023); // subu $24, $24, $28
write32(buf + 16, 0x03e07825); // move $15, $31
write32(buf + 20, 0x0018c082); // srl $24, $24, 2
}
uint32_t jalrInst = config->zHazardplt ? 0x0320fc09 : 0x0320f809;
write32(buf + 24, jalrInst); // jalr.hb $25 or jalr $25
write32(buf + 28, 0x2718fffe); // subu $24, $24, 2
uint64_t gotPlt = in.gotPlt->getVA();
writeValue(buf, gotPlt + 0x8000, 16, 16);
writeValue(buf + 4, gotPlt, 16, 0);
writeValue(buf + 8, gotPlt, 16, 0);
}
template <class ELFT>
void MIPS<ELFT>::writePlt(uint8_t *buf, const Symbol &sym,
uint64_t pltEntryAddr) const {
uint64_t gotPltEntryAddr = sym.getGotPltVA();
if (isMicroMips()) {
// Overwrite trap instructions written by Writer::writeTrapInstr.
memset(buf, 0, pltEntrySize);
if (isMipsR6()) {
write16(buf, 0x7840); // addiupc $2, (GOTPLT) - .
write16(buf + 4, 0xff22); // lw $25, 0($2)
write16(buf + 8, 0x0f02); // move $24, $2
write16(buf + 10, 0x4723); // jrc $25 / jr16 $25
relocateNoSym(buf, R_MICROMIPS_PC19_S2, gotPltEntryAddr - pltEntryAddr);
} else {
write16(buf, 0x7900); // addiupc $2, (GOTPLT) - .
write16(buf + 4, 0xff22); // lw $25, 0($2)
write16(buf + 8, 0x4599); // jrc $25 / jr16 $25
write16(buf + 10, 0x0f02); // move $24, $2
relocateNoSym(buf, R_MICROMIPS_PC23_S2, gotPltEntryAddr - pltEntryAddr);
}
return;
}
uint32_t loadInst = ELFT::Is64Bits ? 0xddf90000 : 0x8df90000;
uint32_t jrInst = isMipsR6() ? (config->zHazardplt ? 0x03200409 : 0x03200009)
: (config->zHazardplt ? 0x03200408 : 0x03200008);
uint32_t addInst = ELFT::Is64Bits ? 0x65f80000 : 0x25f80000;
write32(buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry)
write32(buf + 4, loadInst); // l[wd] $25, %lo(.got.plt entry)($15)
write32(buf + 8, jrInst); // jr $25 / jr.hb $25
write32(buf + 12, addInst); // [d]addiu $24, $15, %lo(.got.plt entry)
writeValue(buf, gotPltEntryAddr + 0x8000, 16, 16);
writeValue(buf + 4, gotPltEntryAddr, 16, 0);
writeValue(buf + 12, gotPltEntryAddr, 16, 0);
}
template <class ELFT>
bool MIPS<ELFT>::needsThunk(RelExpr expr, RelType type, const InputFile *file,
uint64_t branchAddr, const Symbol &s,
int64_t /*a*/) 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 && type != R_MIPS_PC26_S2 &&
type != R_MICROMIPS_26_S1 && type != R_MICROMIPS_PC26_S1)
return false;
auto *f = dyn_cast_or_null<ObjFile<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<Defined>(&s);
// LA25 is required if target file has PIC code
// or target symbol is a PIC symbol.
return d && isMipsPIC<ELFT>(d);
}
template <class ELFT>
int64_t MIPS<ELFT>::getImplicitAddend(const uint8_t *buf, RelType type) const {
const endianness e = ELFT::TargetEndianness;
switch (type) {
case R_MIPS_32:
case R_MIPS_REL32:
case R_MIPS_GPREL32:
case R_MIPS_TLS_DTPREL32:
case R_MIPS_TLS_DTPMOD32:
case R_MIPS_TLS_TPREL32:
return SignExtend64<32>(read32(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(buf) << 2);
case R_MIPS_CALL_HI16:
case R_MIPS_GOT16:
case R_MIPS_GOT_HI16:
case R_MIPS_HI16:
case R_MIPS_PCHI16:
return SignExtend64<16>(read32(buf)) << 16;
case R_MIPS_CALL16:
case R_MIPS_CALL_LO16:
case R_MIPS_GOT_LO16:
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_GD:
case R_MIPS_TLS_GOTTPREL:
case R_MIPS_TLS_LDM:
case R_MIPS_TLS_TPREL_HI16:
case R_MIPS_TLS_TPREL_LO16:
return SignExtend64<16>(read32(buf));
case R_MICROMIPS_GOT16:
case R_MICROMIPS_HI16:
return SignExtend64<16>(readShuffle<e>(buf)) << 16;
case R_MICROMIPS_CALL16:
case R_MICROMIPS_GPREL16:
case R_MICROMIPS_LO16:
case R_MICROMIPS_TLS_DTPREL_HI16:
case R_MICROMIPS_TLS_DTPREL_LO16:
case R_MICROMIPS_TLS_GD:
case R_MICROMIPS_TLS_GOTTPREL:
case R_MICROMIPS_TLS_LDM:
case R_MICROMIPS_TLS_TPREL_HI16:
case R_MICROMIPS_TLS_TPREL_LO16:
return SignExtend64<16>(readShuffle<e>(buf));
case R_MICROMIPS_GPREL7_S2:
return SignExtend64<9>(readShuffle<e>(buf) << 2);
case R_MIPS_PC16:
return SignExtend64<18>(read32(buf) << 2);
case R_MIPS_PC19_S2:
return SignExtend64<21>(read32(buf) << 2);
case R_MIPS_PC21_S2:
return SignExtend64<23>(read32(buf) << 2);
case R_MIPS_PC26_S2:
return SignExtend64<28>(read32(buf) << 2);
case R_MIPS_PC32:
return SignExtend64<32>(read32(buf));
case R_MICROMIPS_26_S1:
return SignExtend64<27>(readShuffle<e>(buf) << 1);
case R_MICROMIPS_PC7_S1:
return SignExtend64<8>(read16(buf) << 1);
case R_MICROMIPS_PC10_S1:
return SignExtend64<11>(read16(buf) << 1);
case R_MICROMIPS_PC16_S1:
return SignExtend64<17>(readShuffle<e>(buf) << 1);
case R_MICROMIPS_PC18_S3:
return SignExtend64<21>(readShuffle<e>(buf) << 3);
case R_MICROMIPS_PC19_S2:
return SignExtend64<21>(readShuffle<e>(buf) << 2);
case R_MICROMIPS_PC21_S1:
return SignExtend64<22>(readShuffle<e>(buf) << 1);
case R_MICROMIPS_PC23_S2:
return SignExtend64<25>(readShuffle<e>(buf) << 2);
case R_MICROMIPS_PC26_S1:
return SignExtend64<27>(readShuffle<e>(buf) << 1);
case R_MIPS_64:
case R_MIPS_TLS_DTPMOD64:
case R_MIPS_TLS_DTPREL64:
case R_MIPS_TLS_TPREL64:
case (R_MIPS_64 << 8) | R_MIPS_REL32:
return read64(buf);
case R_MIPS_COPY:
return config->is64 ? read64(buf) : read32(buf);
case R_MIPS_NONE:
case R_MIPS_JUMP_SLOT:
case R_MIPS_JALR:
// These relocations are defined as not having an implicit addend.
return 0;
default:
internalLinkerError(getErrorLocation(buf),
"cannot read addend for relocation " + toString(type));
return 0;
}
}
static std::pair<uint32_t, uint64_t>
calculateMipsRelChain(uint8_t *loc, RelType 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
RelType type2 = (type >> 8) & 0xff;
RelType 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);
}
static bool isBranchReloc(RelType type) {
return type == R_MIPS_26 || type == R_MIPS_PC26_S2 ||
type == R_MIPS_PC21_S2 || type == R_MIPS_PC16;
}
static bool isMicroBranchReloc(RelType type) {
return type == R_MICROMIPS_26_S1 || type == R_MICROMIPS_PC16_S1 ||
type == R_MICROMIPS_PC10_S1 || type == R_MICROMIPS_PC7_S1;
}
template <class ELFT>
static uint64_t fixupCrossModeJump(uint8_t *loc, RelType type, uint64_t val) {
// Here we need to detect jump/branch from regular MIPS code
// to a microMIPS target and vice versa. In that cases jump
// instructions need to be replaced by their "cross-mode"
// equivalents.
const endianness e = ELFT::TargetEndianness;
bool isMicroTgt = val & 0x1;
bool isCrossJump = (isMicroTgt && isBranchReloc(type)) ||
(!isMicroTgt && isMicroBranchReloc(type));
if (!isCrossJump)
return val;
switch (type) {
case R_MIPS_26: {
uint32_t inst = read32(loc) >> 26;
if (inst == 0x3 || inst == 0x1d) { // JAL or JALX
writeValue(loc, 0x1d << 26, 32, 0);
return val;
}
break;
}
case R_MICROMIPS_26_S1: {
uint32_t inst = readShuffle<e>(loc) >> 26;
if (inst == 0x3d || inst == 0x3c) { // JAL32 or JALX32
val >>= 1;
writeShuffleValue<e>(loc, 0x3c << 26, 32, 0);
return val;
}
break;
}
case R_MIPS_PC26_S2:
case R_MIPS_PC21_S2:
case R_MIPS_PC16:
case R_MICROMIPS_PC16_S1:
case R_MICROMIPS_PC10_S1:
case R_MICROMIPS_PC7_S1:
// FIXME (simon): Support valid branch relocations.
break;
default:
llvm_unreachable("unexpected jump/branch relocation");
}
error(getErrorLocation(loc) +
"unsupported jump/branch instruction between ISA modes referenced by " +
toString(type) + " relocation");
return val;
}
template <class ELFT>
void MIPS<ELFT>::relocate(uint8_t *loc, const Relocation &rel,
uint64_t val) const {
const endianness e = ELFT::TargetEndianness;
RelType type = rel.type;
if (ELFT::Is64Bits || config->mipsN32Abi)
std::tie(type, val) = calculateMipsRelChain(loc, type, val);
// Detect cross-mode jump/branch and fix instruction.
val = fixupCrossModeJump<ELFT>(loc, type, val);
// 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 ||
type == R_MICROMIPS_TLS_DTPREL_HI16 ||
type == R_MICROMIPS_TLS_DTPREL_LO16) {
val -= 0x8000;
}
switch (type) {
case R_MIPS_32:
case R_MIPS_GPREL32:
case R_MIPS_TLS_DTPREL32:
case R_MIPS_TLS_TPREL32:
write32(loc, val);
break;
case R_MIPS_64:
case R_MIPS_TLS_DTPREL64:
case R_MIPS_TLS_TPREL64:
write64(loc, val);
break;
case R_MIPS_26:
writeValue(loc, val, 26, 2);
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) {
writeValue(loc, val + 0x8000, 16, 16);
} else {
checkInt(loc, val, 16, rel);
writeValue(loc, val, 16, 0);
}
break;
case R_MICROMIPS_GOT16:
if (config->relocatable) {
writeShuffleValue<e>(loc, val + 0x8000, 16, 16);
} else {
checkInt(loc, val, 16, rel);
writeShuffleValue<e>(loc, val, 16, 0);
}
break;
case R_MIPS_CALL16:
case R_MIPS_GOT_DISP:
case R_MIPS_GOT_PAGE:
case R_MIPS_GPREL16:
case R_MIPS_TLS_GD:
case R_MIPS_TLS_GOTTPREL:
case R_MIPS_TLS_LDM:
checkInt(loc, val, 16, rel);
LLVM_FALLTHROUGH;
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_TPREL_LO16:
writeValue(loc, val, 16, 0);
break;
case R_MICROMIPS_GPREL16:
case R_MICROMIPS_TLS_GD:
case R_MICROMIPS_TLS_LDM:
checkInt(loc, val, 16, rel);
writeShuffleValue<e>(loc, val, 16, 0);
break;
case R_MICROMIPS_CALL16:
case R_MICROMIPS_CALL_LO16:
case R_MICROMIPS_LO16:
case R_MICROMIPS_TLS_DTPREL_LO16:
case R_MICROMIPS_TLS_GOTTPREL:
case R_MICROMIPS_TLS_TPREL_LO16:
writeShuffleValue<e>(loc, val, 16, 0);
break;
case R_MICROMIPS_GPREL7_S2:
checkInt(loc, val, 7, rel);
writeShuffleValue<e>(loc, val, 7, 2);
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:
writeValue(loc, val + 0x8000, 16, 16);
break;
case R_MICROMIPS_CALL_HI16:
case R_MICROMIPS_GOT_HI16:
case R_MICROMIPS_HI16:
case R_MICROMIPS_TLS_DTPREL_HI16:
case R_MICROMIPS_TLS_TPREL_HI16:
writeShuffleValue<e>(loc, val + 0x8000, 16, 16);
break;
case R_MIPS_HIGHER:
writeValue(loc, val + 0x80008000, 16, 32);
break;
case R_MIPS_HIGHEST:
writeValue(loc, val + 0x800080008000, 16, 48);
break;
case R_MIPS_JALR:
val -= 4;
// Replace jalr/jr instructions by bal/b if the target
// offset fits into the 18-bit range.
if (isInt<18>(val)) {
switch (read32(loc)) {
case 0x0320f809: // jalr $25 => bal sym
write32(loc, 0x04110000 | ((val >> 2) & 0xffff));
break;
case 0x03200008: // jr $25 => b sym
write32(loc, 0x10000000 | ((val >> 2) & 0xffff));
break;
}
}
break;
case R_MICROMIPS_JALR:
// Ignore this optimization relocation for now
break;
case R_MIPS_PC16:
checkAlignment(loc, val, 4, rel);
checkInt(loc, val, 18, rel);
writeValue(loc, val, 16, 2);
break;
case R_MIPS_PC19_S2:
checkAlignment(loc, val, 4, rel);
checkInt(loc, val, 21, rel);
writeValue(loc, val, 19, 2);
break;
case R_MIPS_PC21_S2:
checkAlignment(loc, val, 4, rel);
checkInt(loc, val, 23, rel);
writeValue(loc, val, 21, 2);
break;
case R_MIPS_PC26_S2:
checkAlignment(loc, val, 4, rel);
checkInt(loc, val, 28, rel);
writeValue(loc, val, 26, 2);
break;
case R_MIPS_PC32:
writeValue(loc, val, 32, 0);
break;
case R_MICROMIPS_26_S1:
case R_MICROMIPS_PC26_S1:
checkInt(loc, val, 27, rel);
writeShuffleValue<e>(loc, val, 26, 1);
break;
case R_MICROMIPS_PC7_S1:
checkInt(loc, val, 8, rel);
writeMicroRelocation16<e>(loc, val, 7, 1);
break;
case R_MICROMIPS_PC10_S1:
checkInt(loc, val, 11, rel);
writeMicroRelocation16<e>(loc, val, 10, 1);
break;
case R_MICROMIPS_PC16_S1:
checkInt(loc, val, 17, rel);
writeShuffleValue<e>(loc, val, 16, 1);
break;
case R_MICROMIPS_PC18_S3:
checkInt(loc, val, 21, rel);
writeShuffleValue<e>(loc, val, 18, 3);
break;
case R_MICROMIPS_PC19_S2:
checkInt(loc, val, 21, rel);
writeShuffleValue<e>(loc, val, 19, 2);
break;
case R_MICROMIPS_PC21_S1:
checkInt(loc, val, 22, rel);
writeShuffleValue<e>(loc, val, 21, 1);
break;
case R_MICROMIPS_PC23_S2:
checkInt(loc, val, 25, rel);
writeShuffleValue<e>(loc, val, 23, 2);
break;
default:
llvm_unreachable("unknown relocation");
}
}
template <class ELFT> bool MIPS<ELFT>::usesOnlyLowPageBits(RelType type) const {
return type == R_MIPS_LO16 || type == R_MIPS_GOT_OFST ||
type == R_MICROMIPS_LO16;
}
// Return true if the symbol is a PIC function.
template <class ELFT> bool elf::isMipsPIC(const Defined *sym) {
if (!sym->isFunc())
return false;
if (sym->stOther & STO_MIPS_PIC)
return true;
if (!sym->section)
return false;
ObjFile<ELFT> *file =
cast<InputSectionBase>(sym->section)->template getFile<ELFT>();
if (!file)
return false;
return file->getObj().getHeader().e_flags & EF_MIPS_PIC;
}
template <class ELFT> TargetInfo *elf::getMipsTargetInfo() {
static MIPS<ELFT> target;
return &target;
}
template TargetInfo *elf::getMipsTargetInfo<ELF32LE>();
template TargetInfo *elf::getMipsTargetInfo<ELF32BE>();
template TargetInfo *elf::getMipsTargetInfo<ELF64LE>();
template TargetInfo *elf::getMipsTargetInfo<ELF64BE>();
template bool elf::isMipsPIC<ELF32LE>(const Defined *);
template bool elf::isMipsPIC<ELF32BE>(const Defined *);
template bool elf::isMipsPIC<ELF64LE>(const Defined *);
template bool elf::isMipsPIC<ELF64BE>(const Defined *);
Reference in New Issue View Git Blame Copy Permalink