Summary:
Due to missing relocation support in libdwarf for powerpc64, handling of dwarf
info on unlinked objects was bogus.
Examining raw dwarf data on objects compiled on ppc64 with a modern compiler
(in-tree gcc tends to hide the issue, since it only rarely generates relocations
in .debug_info and uses DW_FORM_str instead of DW_FORM_strp for everything), you
will find that the dwarf data appears corrupt, with repeated references to the
compiler version where things like types and function names should appear.
This happens because the 0 offset of .debug_str contains the compiler version,
and without applying the relocations, *all* indirect strings in .dwarf_info will
end up pointing to it.
This corruption then propogates to the CTF data, as ctfconvert relies on
libdwarf to read the dwarf info, for every compiled object (when building a
kernel.)
However, if you examine the dwarf data on a compiled executable, it will appear
correct, because during final link the relocations get applied and baked in by
the linker.
Submitted by: Brandon Bergren
Reviewed By: emaste
Differential Revision: https://reviews.freebsd.org/D20367
This fixes build failures on older releases that lack various
definitions such as EM_AARCH64 (which was unfixed before this).
Revert all of the recent compatibility changes that worked around this
problem.
This uses the same method of using the in-tree header as lib/libelf,
lib/libdwarf and usr.bin/readelf.
Reviewed by: emaste
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D6734
Highlights (upstream revisions):
- Fix SHT_GROUP handling in elfcopy/strip (3206 3220 3221)
- Misc elfcopy / strip bug fixes (3215 3216 3217)
- Many C++ demangler improvements (3199 3200 3201 3202 3203 3204 3205
3208 3210 3211 3212)
- Improve GNU binutils compatibility in elfcopy / strip (3213 3214)
- Add -g option to readelf(1): dump contents of section groups (3219)
- Add EM_IAMCU 32-bit Intel MCU (3198)
Also add a compat #define for building with older FreeBSD ELF headers.
The GRP_COMDAT flag was added to elf_common.h in r283110, but it's not
available during the bootstrap build. It is also convenient to be able
to build on older hosts.
Thanks to antoine@ for tracking down issues through multiple exp-runs
and to kaiw@ for fixing.
PR: 198611 (exp-run), 200350
Sponsored by: The FreeBSD Foundation
