[PATCH] D71143: [ELF][Hexagon] Add support for TLS IE relocations

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

I'd like to ask some questions which can help understand the situation better.

- Does Hexagon have a binutils port or an alternative linker?
- Is -pie and -shared used a lot on Hexagon?
- How is Hexagon's dynamic loader ld.so implemented? Is the source code available?
- How is TLS going to be used on Hexagon?
- Is text relocations acceptable?
- Is it really impossible to use a PC-relative GOT address load on Hexagon? `R_GOT` on EM_386 has severe limitations. `EM_X86_64` fixed these issues. (I don't want to see newer architectures behave like it.)

I shall also mention that this is unfortunate.

>   bool canRelax = config->emachine != EM_ARM &&
>                   config->emachine != EM_RISCV;

RISC-V TLS has several problems. Its design/implementation was copied from ARM/MIPS. The two architectures really do not provide the best reference for TLS implementations. The RISC-V TLS implementation has several defects. I've reported a few bugs on the binutils bugzilla.


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https://reviews.llvm.org/D71143