[PATCH] D95730: [MC] Support SHF_GNU_RETAIN as section flag 'R'

[Peter Smith via Phabricator via llvm-commits]

peter.smith added a comment.

> Is there any feature triggering ELFOSABI_ARM / ELFOSABI_ARM_AEABI? If there is and such an object file also uses STT_GNU_IFUNC, the single value EI_OSABI is indeed insufficient.

I can't find any. It looks like ELFOSABI_ARM used to be for pre EABI objects, but that seems to not be the case anymore and 0 gets used instead in all versions of GCC that anyone is likely to have used in the past 10 years. There is a use of ELFOSABI_ARM_FDPIC for the FDPIC variant (Linux in a single address space), but that isn't supported in LLVM anyway.

| ELFOSABI_ARM_FDPIC (65) | The object uses relocations in the private range, with semantics defined by [FDPIC]. |
|

The ELFOSABI_ARM_EABI is documented as:

| ELFOSABI_ARM_AEABI (64) | The object contains symbol versioning extensions as described in Symbol Versioning. |  |
|

where the extensions are the GNU extensions, which seem to be universally supported by Arm toolchains, so it is probably redundant now in practice.

The use of OSABI gnu seems to be relatively recent in GCC. My old GCC8 versions set the OSABI to 0 even when ifunc is used.

Anyway I don't think that we need to hold this up over OSABI. It can be done in a separate patch if need be.


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https://reviews.llvm.org/D95730