In function ObjFile<ELFT>::shouldMerge in lld/ELF/InputFiles.cpp: if (sec.sh_size % entSize) fatal(toString(this) + ": SHF_MERGE section size must be a multiple of sh_entsize"); uint64_t flags = sec.sh_flags; if (!(flags & SHF_MERGE)) return false; Notice that the size is checked _before_ looking at whether SHF_MERGE is set. This means that the error is produced for sections that do not have SHF_MERGE set at all, which is either misleading or wrong. Judging by the report in #219717 where this was found, the BFD linker did not care about sh_entsize of non-mergeable sections. If this check is only needed for mergeable sections, then surely it should be made _after_ SHF_MERGE is checked for. Since this check is skipped when -Wl,-O0 is in effect, I do not believe it is actually necessary to check that size is a multiple of sh_entsize when not merging sections. If I'm wrong about that, though, then the check would need to be both moved to somewhere else and changed to not mention SHF_MERGE in the error message.
Would you submit an upstream bug for lld at https://bugs.llvm.org/
(I will look at this as soon as I'm able, if it's not handled upstream first.)
I don't currently have an account for upstream.
Submitted upstream as https://bugs.llvm.org/show_bug.cgi?id=45370
A commit in branch stable/12 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=2f4812936a2ccaadd260f6bbaacd677e6079d9d0 commit 2f4812936a2ccaadd260f6bbaacd677e6079d9d0 Author: Dimitry Andric <dim@FreeBSD.org> AuthorDate: 2021-11-08 10:19:59 +0000 Commit: Dimitry Andric <dim@FreeBSD.org> CommitDate: 2021-11-08 17:29:35 +0000 Fix lld warning "SHF_MERGE section size must be a multiple of sh_entsize" Merge commit 56decd982dc0 from llvm git (by Fangrui Song): [ELF] Allow invalid sh_size%sh_entsize!=0 for non-SHF_MERGE sections Fixes https://bugs.llvm.org/show_bug.cgi?id=45370 Fixes https://github.com/Clozure/ccl/issues/273 .stab holds a table of 12-byte entries. GNU as before 2.35 incorrectly sets sh_entsize(.stab) to 20 on 64-bit architectures: https://sourceware.org/bugzilla/show_bug.cgi?id=25768 We should not emit the confusing error: "SHF_MERGE section size (...) must be a multiple of sh_entsize (20) Reviewed By: grimar, psmith Differential Revision: https://reviews.llvm.org/D77368 Direct commit to stable/12, since newer branches have this fix already. PR: 245179 Reported by: andrew@tao11.riddles.org.uk contrib/llvm-project/lld/ELF/InputFiles.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)