Bug 721344 (libatomic-linking)

Summary:	[Tracker] Libatomic-related build failures on 32-bit arches (non-x86) and riscv
Product:	Gentoo Linux	Reporter:	Sam James <sam>
Component:	Current packages	Assignee:	Gentoo's Team for Core System packages <base-system>
Status:	CONFIRMED ---
Severity:	normal	CC:	gyakovlev, toolchain
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Other
URL:	https://www.mail-archive.com/bug-autoconf@gnu.org/msg04294.html
See Also:	https://bugs.debian.org/907277 https://bugs.gentoo.org/show_bug.cgi?id=543984 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81358 https://gitlab.kitware.com/cmake/cmake/-/merge_requests/8756 https://github.com/mesonbuild/meson/issues/10621 https://github.com/mesonbuild/meson/pull/11445
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:	551956, 734606, 770748, 802162, 820104, 902777, 911759, 918981, 923177, 926265, 453704, 518582, 639678, 668002, 688574, 719662, 720806, 727546, 727652, 734628, 738642, 740464, 764662, 778455, 782811, 790590, 790689, 803470, 803473, 806472, 809830, 820095, 820101, 827203, 828065, 830286, 832675, 832816, 833372, 835003, 836125, 836951, 837740, 847904, 857804, 860078, 864421, 872959, 895308, 906638, 912341
Bug Blocks:	807721

Description Sam James archtester

2020-05-07 01:23:57 UTC

Typical errors look like:
>proto_http.c:(.text+0xbfc): undefined reference to `__atomic_fetch_add_8'

gyakovlev has investigated this here: https://bugs.gentoo.org/719662#c3.

The gist is that libatomic is not always part of libstdc++. It looks like this is the case on non-x86 32 bit arches, but arm in at least some of these bugs has already been identified by upstream and handled in their build system.

Patches should be trivial in just adding -latomic on ppc/other 32-bit arches. With --as-needed in LDFLAGS, it shouldn't matter if we add it when it's unnecessary, I think.

We may need to come up with a neat macro/conditional to cleanly match only e.g. ppc and not ppc64.

Comment 1 Sam James archtester

2020-05-07 01:32:21 UTC

I have assigned this to base-system@ for now because it seems to be an autoconf bug exposed by newer versions of GCC (>= 8).

Please reassign if you feel this is not appropriate.

Comment 2 Georgy Yakovlev archtester

2020-05-07 01:44:02 UTC

ppc32 check should generally be

> defined(__powerpc__) && !defined(__powerpc64__)

because __powerpc__ also defined on ppc64 hosts.