There used to be many cases where addends for Elf_Rel were not emitted in
the final object file (mostly when building for MIPS64 since the input .o
files use RELA but the output uses REL). These cases have been fixed since,
but this patch adds a check to ensure that the written values are correct.
It is based on a previous patch that I added to the CHERI fork of LLD since
we were using MIPS64 as a baseline. The work has now almost entirely
shifted to RISC-V and Arm Morello (which use Elf_Rela), but I thought
it would be useful to upstream our local changes anyway.
This patch adds a (hidden) command line flag --check-dynamic-relocations
that can be used to enable these checks. It is also on by default in
assertions builds for targets that handle all dynamic relocations kinds
that LLD can emit in Target::getImplicitAddend(). Currently this is
enabled for ARM, MIPS, and I386.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D101450
It allows handling cases when we have SHT_REL[A] sections before target
sections in objects.
This fixes https://bugs.llvm.org/show_bug.cgi?id=46632
which says: "Normally it is not what compilers would emit. We have to support it,
because some custom tools might want to use this feature, which is not restricted by ELF gABI"
Differential revision: https://reviews.llvm.org/D83469
Alex Richardson