For
add %reg1, name@GOTTPOFF(%rip), %reg2
add name@GOTTPOFF(%rip), %reg1, %reg2
{nf} add %reg1, name@GOTTPOFF(%rip), %reg2
{nf} add name@GOTTPOFF(%rip), %reg1, %reg2
{nf} add name@GOTTPOFF(%rip), %reg
add
`R_X86_64_CODE_6_GOTTPOFF` = 50
if the instruction starts at 6 bytes before the relocation offset. It's
similar to R_X86_64_GOTTPOFF.
Linker can treat `R_X86_64_CODE_6_GOTTPOFF` as `R_X86_64_GOTTPOFF` or
convert the instructions above to
add $name@tpoff, %reg1, %reg2
add $name@tpoff, %reg1, %reg2
{nf} add $name@tpoff, %reg1, %reg2
{nf} add $name@tpoff, %reg1, %reg2
{nf} add $name@tpoff, %reg
if the first byte of the instruction at the relocation `offset - 6` is
`0xd5` (namely, encoded w/REX2 prefix) when possible.
Binutils patch:
5bc71c2a6b
Binutils mailthread:
https://sourceware.org/pipermail/binutils/2024-February/132351.html
ABI discussion:
https://groups.google.com/g/x86-64-abi/c/FhEZjCtDLFw/m/VHDjN4orAgAJ
Blog: https://kanrobert.github.io/rfc/All-about-APX-relocation
ab4e06667d