[PATCH] D92260: [ELF] Error for undefined foo at v1

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, jhenderson, psmith.
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MaskRay requested review of this revision.

If an object file has an undefined foo at v1, we emit a dynamic symbol foo.
This is incorrect if at runtime a shared object provides the non-default version foo at v1
(the undefined foo may bind to foo@@v2, for example).

GNU ld issues an error for this case, even if foo at v1 is undefined weak
(https://sourceware.org/bugzilla/show_bug.cgi?id=3351). This behavior makes
sense because to represent an undefined foo at v1, we have to construct a Verneed
entry. However, without knowing the defining filename, we cannot construct a
Verneed entry.

This patch implements the error.

Depends on D92258 <https://reviews.llvm.org/D92258>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92260

Files:
  lld/ELF/Relocations.cpp
  lld/test/ELF/lto/version-script2.ll
  lld/test/ELF/symver.s

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