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Differential D14720 Diff 40383 contrib/llvm/tools/lld/ELF/Arch/X86.cpp

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contrib/llvm/tools/lld/ELF/Arch/X86.cpp

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using namespace llvm; using namespace llvm;
using namespace llvm::support::endian; using namespace llvm::support::endian;
using namespace llvm::ELF; using namespace llvm::ELF;
using namespace lld; using namespace lld;
using namespace lld::elf; using namespace lld::elf;
namespace { namespace {
class X86 final : public TargetInfo { class X86 : public TargetInfo {
public: public:
X86(); X86();
RelExpr getRelExpr(uint32_t Type, const SymbolBody &S, RelExpr getRelExpr(uint32_t Type, const SymbolBody &S,
const uint8_t *Loc) const override; const uint8_t *Loc) const override;
int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; int64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override;
void writeGotPltHeader(uint8_t *Buf) const override; void writeGotPltHeader(uint8_t *Buf) const override;
uint32_t getDynRel(uint32_t Type) const override; uint32_t getDynRel(uint32_t Type) const override;
void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override;
▲ Show 20 Lines • Show All 320 Lines • ▼ Show 20 Linesvoid X86::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const {
const uint8_t Inst[] = { const uint8_t Inst[] = {
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0,%eax 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0,%eax
0x90, // nop 0x90, // nop
0x8d, 0x74, 0x26, 0x00 // leal 0(%esi,1),%esi 0x8d, 0x74, 0x26, 0x00 // leal 0(%esi,1),%esi
}; };
memcpy(Loc - 2, Inst, sizeof(Inst)); memcpy(Loc - 2, Inst, sizeof(Inst));
} }
namespace {
class RetpolinePic : public X86 {
public:
RetpolinePic();
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;
};
class RetpolineNoPic : public X86 {
public:
RetpolineNoPic();
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;
};
} // namespace
RetpolinePic::RetpolinePic() {
PltHeaderSize = 48;
PltEntrySize = 32;
}
void RetpolinePic::writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {
write32le(Buf, S.getPltVA() + 17);
}
void RetpolinePic::writePltHeader(uint8_t *Buf) const {
const uint8_t Insn[] = {
0xff, 0xb3, 0, 0, 0, 0, // 0: pushl GOTPLT+4(%ebx)
0x50, // 6: pushl %eax
0x8b, 0x83, 0, 0, 0, 0, // 7: mov GOTPLT+8(%ebx), %eax
0xe8, 0x0e, 0x00, 0x00, 0x00, // d: call next
0xf3, 0x90, // 12: loop: pause
0x0f, 0xae, 0xe8, // 14: lfence
0xeb, 0xf9, // 17: jmp loop
0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // 19: int3; .align 16
0x89, 0x0c, 0x24, // 20: next: mov %ecx, (%esp)
0x8b, 0x4c, 0x24, 0x04, // 23: mov 0x4(%esp), %ecx
0x89, 0x44, 0x24, 0x04, // 27: mov %eax ,0x4(%esp)
0x89, 0xc8, // 2b: mov %ecx, %eax
0x59, // 2d: pop %ecx
0xc3, // 2e: ret
0xcc, // 2f: int3
};
memcpy(Buf, Insn, sizeof(Insn));
assert(sizeof(Insn) == TargetInfo::PltHeaderSize);
uint32_t Ebx = InX::Got->getVA() + InX::Got->getSize();
uint32_t GotPlt = InX::GotPlt->getVA() - Ebx;
write32le(Buf + 2, GotPlt + 4);
write32le(Buf + 9, GotPlt + 8);
}
void RetpolinePic::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const uint8_t Insn[] = {
0x50, // pushl %eax
0x8b, 0x83, 0, 0, 0, 0, // mov foo@GOT(%ebx), %eax
0xe8, 0, 0, 0, 0, // call plt+0x20
0xe9, 0, 0, 0, 0, // jmp plt+0x12
0x68, 0, 0, 0, 0, // pushl $reloc_offset
0xe9, 0, 0, 0, 0, // jmp plt+0
0xcc, 0xcc, 0xcc, 0xcc, 0xcc,
};
memcpy(Buf, Insn, sizeof(Insn));
assert(sizeof(Insn) == TargetInfo::PltEntrySize);
uint32_t Ebx = InX::Got->getVA() + InX::Got->getSize();
write32le(Buf + 3, GotPltEntryAddr - Ebx);
write32le(Buf + 8, -Index * PltEntrySize - PltHeaderSize - 12 + 32);
write32le(Buf + 13, -Index * PltEntrySize - PltHeaderSize - 17 + 18);
write32le(Buf + 18, RelOff);
write32le(Buf + 23, -Index * PltEntrySize - PltHeaderSize - 27);
}
RetpolineNoPic::RetpolineNoPic() {
PltHeaderSize = 48;
PltEntrySize = 32;
}
void RetpolineNoPic::writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {
write32le(Buf, S.getPltVA() + 16);
}
void RetpolineNoPic::writePltHeader(uint8_t *Buf) const {
const uint8_t PltData[] = {
0xff, 0x35, 0, 0, 0, 0, // 0: pushl GOTPLT+4
0x50, // 6: pushl %eax
0xa1, 0, 0, 0, 0, // 7: mov GOTPLT+8, %eax
0xe8, 0x0f, 0x00, 0x00, 0x00, // c: call next
0xf3, 0x90, // 11: loop: pause
0x0f, 0xae, 0xe8, // 13: lfence
0xeb, 0xf9, // 16: jmp loop
0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // 18: int3
0xcc, 0xcc, 0xcc, // 1f: int3; .align 16
0x89, 0x0c, 0x24, // 20: next: mov %ecx, (%esp)
0x8b, 0x4c, 0x24, 0x04, // 23: mov 0x4(%esp), %ecx
0x89, 0x44, 0x24, 0x04, // 27: mov %eax ,0x4(%esp)
0x89, 0xc8, // 2b: mov %ecx, %eax
0x59, // 2d: pop %ecx
0xc3, // 2e: ret
0xcc, // 2f: int3
};
memcpy(Buf, PltData, sizeof(PltData));
assert(sizeof(PltData) == TargetInfo::PltHeaderSize);
uint32_t GotPlt = InX::GotPlt->getVA();
write32le(Buf + 2, GotPlt + 4);
write32le(Buf + 8, GotPlt + 8);
}
void RetpolineNoPic::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr,
uint64_t PltEntryAddr, int32_t Index,
unsigned RelOff) const {
const uint8_t Insn[] = {
0x50, // 0: pushl %eax
0xa1, 0, 0, 0, 0, // 1: mov foo_in_GOT, %eax
0xe8, 0, 0, 0, 0, // 6: call plt+0x20
0xe9, 0, 0, 0, 0, // b: jmp plt+0x11
0x68, 0, 0, 0, 0, // 10: pushl $reloc_offset
0xe9, 0, 0, 0, 0, // 15: jmp plt+0
0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc,
};
memcpy(Buf, Insn, sizeof(Insn));
assert(sizeof(Insn) == TargetInfo::PltEntrySize);
write32le(Buf + 2, GotPltEntryAddr);
write32le(Buf + 7, -Index * PltEntrySize - PltHeaderSize - 11 + 32);
write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16 + 17);
write32le(Buf + 17, RelOff);
write32le(Buf + 22, -Index * PltEntrySize - PltHeaderSize - 26);
}
TargetInfo *elf::getX86TargetInfo() { TargetInfo *elf::getX86TargetInfo() {
static X86 Target; if (Config->ZRetpolineplt) {
return &Target; if (Config->Pic) {
static RetpolinePic T;
return &T;
}
static RetpolineNoPic T;
return &T;
}
static X86 T;
return &T;
} }