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Early return. NFC. 

llvm-svn: 272973
This commit is contained in:
Rui Ueyama 2016-06-16 23:28:05 +00:00
parent bebf4897a3
commit a71ba43ed3
1 changed files with 21 additions and 21 deletions
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42
lld/ELF/Target.cpp
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@ -866,38 +866,38 @@ void X86_64TargetInfo::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.
// Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg".
if (Op == 0x8b) {
Loc[-2] = 0x8d;
relocateOne(Loc, R_X86_64_PC32, 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 (Op == 0xff) {
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 instruction
// prefix. That makes result expression to be a single instruction.
Loc[-2] = 0x67; // addr32 prefix
Loc[-1] = 0xe8; // call
} else {
assert(ModRm == 0x25);
// 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.
Loc[-2] = 0xe9; // jmp
Loc[3] = 0x90; // nop
Loc -= 1;
Val += 1;
}
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
relocateOne(Loc, R_X86_64_PC32, Val);
return;
}
assert(!Config->Pic);
// We are relaxing a rip relative to an absolute, so compensate
// for the old -4 addend.
relaxGotNoPic(Loc, Val + 4, Op, ModRm);
// 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
relocateOne(Loc - 1, R_X86_64_PC32, Val + 1);
}
// Relocation masks following the #lo(value), #hi(value), #ha(value),