tree 56ef3e6f8a1847669e4aa92eedd9f8bee606f0ef
parent 1c897fec44a6abc6cd13c72b571a13fffbab3d90
author Fangrui Song <i@maskray.me> 1637692211 -0800
committer Copybara-Service <copybara-worker@google.com> 1637692594 -0800

[ELF] Support non-RAX/non-adjacent R_X86_64_GOTPC32_TLSDESC/R_X86_64_TLSDESC_CALL

The current TLSDESC optimization code assumes:
```
leaq x@tlsdesc(%rip), %rax
call *x@tlscall(%rax)       # adjacent
```

From https://gitlab.freedesktop.org/mesa/mesa/-/issues/5665 , it seems that the
two instructions may not be adjacent in GCC 10's output:
```
leaq x@tlsdesc(%rip), %rax
something else
call *x@tlscall(%rax)
```

This patch supports the case. While here, support non-RAX registers for
R_X86_64_GOTPC32_TLSDESC, in case the compiler generates inefficient:

```
leaq x@tlsdesc(%rip), %rcx  # or %rdx, %rbx, %rdi, ...
movq %rcx, %rax
call *x@tlscall(%rax)       # GNU ld/gold error for non-RAX
```

Differential Revision: https://reviews.llvm.org/D114416

GitOrigin-RevId: 38ed1db7e8740fce236d1893ff9e20cc22ef0ada