[PATCH] D94329: [lld-macho] Fix TLV data initialization

[Jez Ng via Phabricator via llvm-commits]

int3 created this revision.
int3 added a reviewer: lld-macho.
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We were mishandling the case where both __tbss and __thread_data sections were
present.

TLVP relocations should be encoded as offsets from the start of `__thread_data`,
even if the symbol is actually located in `__thread_bss`. Previously, we were
writing the offset from the start of the containing section, which doesn't
really make sense since there's no way `tlv_get_addr()` can know which section a
given `tlv$init` symbol is in at runtime.

In addition, this patch ensures that we place `__thread_data` immediately before
`__thread_bss`. This is what ld64 does, likely for performance reasons. Zerofill
sections must also be at the end of their segments; we were already doing this,
but now we ensure that `__thread_bss` occurs before `__bss`, so that it's always
possible to have it contiguous with `__thread_data`.

Fixes llvm.org/PR48657.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94329

Files:
  lld/MachO/InputSection.cpp
  lld/MachO/InputSection.h
  lld/MachO/Writer.cpp
  lld/MachO/Writer.h
  lld/test/MachO/bss.s
  lld/test/MachO/tlv.s

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