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[ELF] Delete relOff from TargetInfo::writePLT 

This change only affects EM_386. relOff can be computed from `index`
easily, so it is unnecessarily passed as a parameter.

Both in.plt and in.iplt entries are written by writePLT. For in.iplt,
the instruction `push reloc_offset` will change because `index` is now
different. Fortunately, this does not matter because `push; jmp` is only
used by PLT. IPLT does not need the code sequence.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D71518
This commit is contained in:
Fangrui Song 2019-12-14 15:09:43 -08:00
parent 98afa2c1f1
commit 90d195d026
14 changed files with 40 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lld/ELF/Arch/AArch64.cpp
View File

@ -38,7 +38,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
uint64_t branchAddr, const Symbol &s,
int64_t a) const override;
@ -214,8 +214,7 @@ void AArch64::writePltHeader(uint8_t *buf) const {
}
void AArch64::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) 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]))]
@ -570,7 +569,7 @@ public:
AArch64BtiPac();
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;
int32_t index) const override;
private:
bool btiHeader; // bti instruction needed in PLT Header
@ -630,8 +629,7 @@ void AArch64BtiPac::writePltHeader(uint8_t *buf) const {
}
void AArch64BtiPac::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
// The PLT entry is of the form:
// [btiData] addrInst (pacBr | stdBr) [nopData]
const uint8_t btiData[] = { 0x5f, 0x24, 0x03, 0xd5 }; // bti c

10
lld/ELF/Arch/ARM.cpp
View File

@ -35,7 +35,7 @@ public:
void writeIgotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
void addPltSymbols(InputSection &isec, uint64_t off) const override;
void addPltHeaderSymbols(InputSection &isd) const override;
bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
@ -216,8 +216,7 @@ void ARM::addPltHeaderSymbols(InputSection &isec) const {
// Long form PLT entries that do not have any restrictions on the displacement
// of the .plt from the .plt.got.
static void writePltLong(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) {
uint64_t pltEntryAddr) {
const uint8_t pltData[] = {
0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2
0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc
@ -232,8 +231,7 @@ static void writePltLong(uint8_t *buf, uint64_t gotPltEntryAddr,
// The default PLT entries require the .plt.got to be within 128 Mb of the
// .plt in the positive direction.
void ARM::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t /*index*/) const {
// The PLT entry is similar to the example given in Appendix A of ELF for
// the Arm Architecture. Instead of using the Group Relocations to find the
// optimal rotation for the 8-bit immediate used in the add instructions we
@ -248,7 +246,7 @@ void ARM::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t offset = gotPltEntryAddr - pltEntryAddr - 8;
if (!llvm::isUInt<27>(offset)) {
// We cannot encode the Offset, use the long form.
writePltLong(buf, gotPltEntryAddr, pltEntryAddr, index, relOff);
writePltLong(buf, gotPltEntryAddr, pltEntryAddr);
return;
}
write32le(buf + 0, pltData[0] | ((offset >> 20) & 0xff));

5
lld/ELF/Arch/Hexagon.cpp
View File

@ -34,7 +34,7 @@ public:
void relocateOne(uint8_t *loc, RelType type, uint64_t val) 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;
int32_t index) const override;
};
} // namespace
@ -303,8 +303,7 @@ void Hexagon::writePltHeader(uint8_t *buf) const {
}
void Hexagon::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
const uint8_t inst[] = {
0x00, 0x40, 0x00, 0x00, // { immext (#0)
0x0e, 0xc0, 0x49, 0x6a, // r14 = add (pc, ##GOTn@PCREL) }

5
lld/ELF/Arch/Mips.cpp
View File

@ -33,7 +33,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
uint64_t branchAddr, const Symbol &s,
int64_t a) const override;
@ -319,8 +319,7 @@ template <class ELFT> void MIPS<ELFT>::writePltHeader(uint8_t *buf) const {
template <class ELFT>
void MIPS<ELFT>::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t /*index*/) const {
if (isMicroMips()) {
// Overwrite trap instructions written by Writer::writeTrapInstr.
memset(buf, 0, pltEntrySize);

2
lld/ELF/Arch/PPC.cpp
View File

@ -32,7 +32,7 @@ public:
llvm_unreachable("should call writePPC32GlinkSection() instead");
}
void writePlt(uint8_t *buf, uint64_t gotPltEntryAddr, uint64_t pltEntryAddr,
int32_t index, unsigned relOff) const override {
int32_t index) const override {
llvm_unreachable("should call writePPC32GlinkSection() instead");
}
void writeGotPlt(uint8_t *buf, const Symbol &s) const override;

5
lld/ELF/Arch/PPC64.cpp
View File

@ -201,7 +201,7 @@ public:
RelType getDynRel(RelType type) 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;
int32_t index) const override;
void relocateOne(uint8_t *loc, RelType type, uint64_t val) const override;
void writeGotHeader(uint8_t *buf) const override;
bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
@ -669,8 +669,7 @@ void PPC64::writePltHeader(uint8_t *buf) const {
}
void PPC64::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
int32_t offset = pltHeaderSize + index * pltEntrySize;
// bl __glink_PLTresolve
write32(buf, 0x48000000 | ((-offset) & 0x03FFFFFc));

5
lld/ELF/Arch/RISCV.cpp
View File

@ -28,7 +28,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
RelType getDynRel(RelType type) const override;
RelExpr getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const override;
@ -163,8 +163,7 @@ void RISCV::writePltHeader(uint8_t *buf) const {
}
void RISCV::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t /*index*/) const {
// 1: auipc t3, %pcrel_hi(f@.got.plt)
// l[wd] t3, %pcrel_lo(1b)(t3)
// jalr t1, t3

5
lld/ELF/Arch/SPARCV9.cpp
View File

@ -27,7 +27,7 @@ public:
RelExpr getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const override;
void writePlt(uint8_t *buf, uint64_t gotEntryAddr, uint64_t pltEntryAddr,
int32_t index, unsigned relOff) const override;
int32_t index) const override;
void relocateOne(uint8_t *loc, RelType type, uint64_t val) const override;
};
} // namespace
@ -125,8 +125,7 @@ void SPARCV9::relocateOne(uint8_t *loc, RelType type, uint64_t val) const {
}
void SPARCV9::writePlt(uint8_t *buf, uint64_t gotEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
const uint8_t pltData[] = {
0x03, 0x00, 0x00, 0x00, // sethi (. - .PLT0), %g1
0x30, 0x68, 0x00, 0x00, // ba,a %xcc, .PLT1

18
lld/ELF/Arch/X86.cpp
View File

@ -34,7 +34,7 @@ public:
void writeIgotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
void relocateOne(uint8_t *loc, RelType type, uint64_t val) const override;
RelExpr adjustRelaxExpr(RelType type, const uint8_t *data,
@ -214,8 +214,8 @@ void X86::writePltHeader(uint8_t *buf) const {
}
void X86::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
unsigned relOff = in.relaPlt->entsize * index;
if (config->isPic) {
const uint8_t inst[] = {
0xff, 0xa3, 0, 0, 0, 0, // jmp *foo@GOT(%ebx)
@ -416,7 +416,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
};
class RetpolineNoPic : public X86 {
@ -425,7 +425,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
};
} // namespace
@ -460,8 +460,8 @@ void RetpolinePic::writePltHeader(uint8_t *buf) const {
}
void RetpolinePic::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
unsigned relOff = in.relaPlt->entsize * index;
const uint8_t insn[] = {
0x50, // pushl %eax
0x8b, 0x83, 0, 0, 0, 0, // mov foo@GOT(%ebx), %eax
@ -518,8 +518,8 @@ void RetpolineNoPic::writePltHeader(uint8_t *buf) const {
}
void RetpolineNoPic::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
unsigned relOff = in.relaPlt->entsize * index;
const uint8_t insn[] = {
0x50, // 0: pushl %eax
0xa1, 0, 0, 0, 0, // 1: mov foo_in_GOT, %eax

15
lld/ELF/Arch/X86_64.cpp
View File

@ -34,7 +34,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
void relocateOne(uint8_t *loc, RelType type, uint64_t val) const override;
RelExpr adjustRelaxExpr(RelType type, const uint8_t *data,
@ -156,8 +156,7 @@ void X86_64::writePltHeader(uint8_t *buf) const {
}
void X86_64::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
const uint8_t inst[] = {
0xff, 0x25, 0, 0, 0, 0, // jmpq *got(%rip)
0x68, 0, 0, 0, 0, // pushq <relocation index>
@ -584,7 +583,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
};
class RetpolineZNow : public X86_64 {
@ -593,7 +592,7 @@ public:
void writeGotPlt(uint8_t *buf, const Symbol &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;
int32_t index) const override;
};
} // namespace
@ -629,8 +628,7 @@ void Retpoline::writePltHeader(uint8_t *buf) const {
}
void Retpoline::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
const uint8_t insn[] = {
0x4c, 0x8b, 0x1d, 0, 0, 0, 0, // 0: mov foo@GOTPLT(%rip), %r11
0xe8, 0, 0, 0, 0, // 7: callq plt+0x20
@ -672,8 +670,7 @@ void RetpolineZNow::writePltHeader(uint8_t *buf) const {
}
void RetpolineZNow::writePlt(uint8_t *buf, uint64_t gotPltEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {
uint64_t pltEntryAddr, int32_t index) const {
const uint8_t insn[] = {
0x4c, 0x8b, 0x1d, 0, 0, 0, 0, // mov foo@GOTPLT(%rip), %r11
0xe9, 0, 0, 0, 0, // jmp plt+0

8
lld/ELF/SyntheticSections.cpp
View File

@ -2471,17 +2471,11 @@ void PltSection::writeTo(uint8_t *buf) {
target->writePltHeader(buf);
size_t off = headerSize;
RelocationBaseSection *relSec = isIplt ? in.relaIplt : in.relaPlt;
// The IPlt is immediately after the Plt, account for this in relOff
size_t pltOff = isIplt ? in.plt->getSize() : 0;
for (size_t i = 0, e = entries.size(); i != e; ++i) {
const Symbol *b = entries[i];
unsigned relOff = relSec->entsize * i + pltOff;
uint64_t got = b->getGotPltVA();
uint64_t plt = this->getVA() + off;
target->writePlt(buf + off, got, plt, b->pltIndex, relOff);
target->writePlt(buf + off, got, plt, b->pltIndex);
off += target->pltEntrySize;
}
}

3
lld/ELF/Target.h
View File

@ -42,8 +42,7 @@ public:
virtual void writePltHeader(uint8_t *buf) const {}
virtual void writePlt(uint8_t *buf, uint64_t gotEntryAddr,
uint64_t pltEntryAddr, int32_t index,
unsigned relOff) const {}
uint64_t pltEntryAddr, int32_t index) const {}
virtual void addPltHeaderSymbols(InputSection &isec) const {}
virtual void addPltSymbols(InputSection &isec, uint64_t off) const {}

4
lld/test/ELF/gnu-ifunc-i386.s
View File

@ -122,11 +122,11 @@
// DISASM-EMPTY:
// DISASM-NEXT: foo:
// DISASM-NEXT: 401100: jmpl *4202784
// DISASM-NEXT: pushl $16
// DISASM-NEXT: pushl $0
// DISASM-NEXT: jmp -32 <_start+0xa>
// DISASM: bar:
// DISASM-NEXT: 401110: jmpl *4202788
// DISASM-NEXT: pushl $24
// DISASM-NEXT: pushl $8
// DISASM-NEXT: jmp -48 <_start+0xa>
.text

4
lld/test/ELF/gnu-ifunc-plt-i386.s
View File

@ -62,10 +62,10 @@
// DISASM-NEXT: pushl $8
// DISASM-NEXT: jmp -48 <.plt>
// DISASM-NEXT: jmpl *4207276
// DISASM-NEXT: pushl $48
// DISASM-NEXT: pushl $0
// DISASM-NEXT: jmp -32 <zed2@plt>
// DISASM-NEXT: jmpl *4207280
// DISASM-NEXT: pushl $56
// DISASM-NEXT: pushl $8
// DISASM-NEXT: jmp -48 <zed2@plt>
.text