[PATCH] D62059: [ELF] Don't align PT_TLS's p_memsz

[Ryan Prichard via Phabricator via llvm-commits]

rprichard added a comment.

I had suggested doing something like this at https://reviews.llvm.org/D53906#1326683. I like the idea, but I think we need to fix up the variant 2 case in getTlsTpOffset:

  case EM_386:
  case EM_X86_64:
    // Variant 2. The TLS segment is located just before the thread pointer.
    return -Out::TlsPhdr->p_memsz;

e.g. If the TLS segment is 4-bytes in size with 8-byte alignment (and assuming p_vaddr % p_align == 0), then the segment will be located at TP-8 on variant 2 targets, not TP-4.

I haven't tested this, but something like this would probably work:

  return -alignTo(Out::TlsPhdr->p_memsz, Out::TlsPhdr->p_align);

Otherwise, lld and the loader will disagree about the location of TLS symbols.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D62059/new/

https://reviews.llvm.org/D62059