[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
4 files changed
tree: 56ef3e6f8a1847669e4aa92eedd9f8bee606f0ef
  1. cmake/
  2. COFF/
  3. Common/
  4. docs/
  5. ELF/
  6. include/
  7. lib/
  8. MachO/
  9. MinGW/
  10. test/
  11. tools/
  12. unittests/
  13. utils/
  14. wasm/
  15. .clang-format
  16. .clang-tidy
  17. .gitignore
  18. CMakeLists.txt
  19. CODE_OWNERS.TXT
  20. LICENSE.TXT
  21. README.md
README.md

LLVM Linker (lld)

This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.

lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.

Benchmarking

In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.

It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz

The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.