[PATCH] D85080: [lld-macho] Support static linking against thread-locals

[Jez Ng via Phabricator via llvm-commits]

int3 created this revision.
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Note: What ELF refers to as "TLS", Mach-O seems to refer to as "TLV", i.e.
thread-local variables.

This diff implements support for TLV relocations that reference defined
symbols. On x86_64, TLV relocations are always used with movq opcodes, so for
defined TLVs, we don't need to create a synthetic section to store the
addresses of the symbols -- we can just convert the `movq` to a `leaq`.

One notable quirk of Mach-O's TLVs is that absolute-address relocations
inside TLV-defining sections behave differently -- their addresses are
no longer absolute, but relative to the start of the target section.
(AFAICT, RIP-relative relocations are not allowed in these sections.)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85080

Files:
  lld/MachO/Arch/X86_64.cpp
  lld/MachO/InputSection.cpp
  lld/MachO/InputSection.h
  lld/MachO/SyntheticSections.cpp
  lld/MachO/Target.h
  lld/test/MachO/Inputs/MacOSX.sdk/usr/lib/libSystem.tbd
  lld/test/MachO/invalid/bad-tlv-def.s
  lld/test/MachO/invalid/bad-tlv-opcode.s
  lld/test/MachO/tlv.s

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