tree f1b14b4f913339978a8e3a6c1d0146f63abfa25e
parent 49042c57ce1b49a303adc0ed2ccc1b1763cfe0bc
author Peter Collingbourne <peter@pcc.me.uk> 1569874980 +0000
committer Peter Collingbourne <peter@pcc.me.uk> 1569874980 +0000

ELF: Don't merge SHF_LINK_ORDER sections for different output sections in relocatable links.

Merging SHF_LINK_ORDER sections can affect semantics if the sh_link
fields point to different sections.

Specifically, for SHF_LINK_ORDER sections, the sh_link field acts as a reverse
dependency from the linked section, causing the SHF_LINK_ORDER section to
be included if the linked section is included. Merging sections with different
sh_link fields will cause the entire contents of the SHF_LINK_ORDER section
to be associated with a single (arbitrarily chosen) output section, whereas the
correct semantics are for the individual pieces of the SHF_LINK_ORDER section
to be associated with their linked output sections. As a result we can end up
incorrectly dropping SHF_LINK_ORDER section contents or including the wrong
section contents, depending on which linked sections were chosen.

Differential Revision: https://reviews.llvm.org/D68094

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@373255 91177308-0d34-0410-b5e6-96231b3b80d8