[PATCH] D53906: [ELF] Allow configuring the TLS layout for an Android executable

[Peter Smith via Phabricator via llvm-commits]

peter.smith added a comment.

Increasing the alignment of the TLS segment is an interesting idea as it allows the possibility of a larger TCB and in theory could also be used by the loader to detect compatible ELF files (reject those without the alignment).

One possible way to achieve this without linker changes would be for the Android startup equivalent crt0.s to have a zero sized TLS .data section with 16 byte alignment. This would have the problem that all executables and shared libraries that didn't use TLS would get a 0 sized TLS segment.

If changes were made to the linker I think it probably would be best to search for the TLS segment and increase its alignment to 16 if it exists. That would work with both arbitrary linker scripts where the author may forget to increase the alignment; and the "internal" linker script which in theory we could just up the alignment to 16.


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D53906