NetBSD Problem Report #52528

From Manuel.Bouyer@lip6.fr Tue Sep 5 08:51:10 2017
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Message-Id: <20170905085004.4043EA936@armandeche.soc.lip6.fr>
Date: Tue, 5 Sep 2017 10:50:04 +0200 (MEST)
From: Manuel.Bouyer@lip6.fr
Reply-To: Manuel.Bouyer@lip6.fr
To: gnats-bugs@NetBSD.org
Subject: CPUFLAGS=-mfpu=neon-vfpv4 breaks some programs
X-Send-Pr-Version: 3.95
>Number: 52528
>Category: port-arm
>Synopsis: CPUFLAGS=-mfpu=neon-vfpv4 breaks some programs
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: port-arm-maintainer
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Tue Sep 05 08:55:00 +0000 2017
>Originator: Manuel Bouyer
>Release: NetBSD 8.0_BETA
>Organization:
>Environment:
System: NetBSD chartplotter 8.0_BETA NetBSD 8.0_BETA (CUBIEBOARD) #0: Fri Sep 1 13:15:30 CEST 2017 bouyer@bop.soc.lip6.fr:/dsk/l1/misc/bouyer/tmp/earmv7hf/obj/dsk/l1/misc/bouyer/netbsd-8/src/sys/arch/evbarm/compile/CUBIEBOARD evbarm
Architecture: earmv7hf
Machine: evbarm
>Description:
	building a release with
	./build.sh -m evbarm -a earmv7hf -V CPUFLAGS="-mfpu=neon-vfpv4" 
	(call this a earmv7hf-neonvfpv4 release) cause some programs to
	fail on the target system.
	Here is an example:
cat > /tmp/conftest.cpp << EOF
// (C) Copyright John Maddock 2001. 
// Use, modification and distribution are subject to the 
// Boost Software License, Version 1.0. (See accompanying file 
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// See http://www.boost.org/libs/config for most recent version.
// MACRO: BOOST_NO_EXCEPTIONS
// TITLE: exception handling support
// DESCRIPTION: The compiler in its current translation mode supports
// exception handling.
namespace boost_no_exceptions{
void throw_it(int i)
{
 throw i;
}
int test()
{
 try
 {
 throw_it(2);
 }
 catch(int i)
 {
 return (i == 2) ? 0 : -1;
 }
 catch(...)
 {
 return -1;
 }
 return -1;
}
}
int main(){ return boost_no_exceptions::test(); }
EOF
c++ -o conftest conftest.c
	It doens't matter if the program is built on earmv7hf-neonvfpv4 or
	plain earmv7hf. When run on earmv7hf the program runs as expected,
	on earmv7hf-neonvfpv4 it fails with:
terminate called after throwing an instance of 'int'
terminate called recursively
Abort (core dumped)
	I tracked it down to libc (running on a plain earmv7hf with the
	earmv7hf-neonvfpv4 libc is enough to make it fail), and more
	specifically to libunwind.o in libc: on a earmv7hf-neonvfpv4 system,
c++ -static -o conftest conftest.c
	gives a non-working program, but
c++ -static -o conftest conftest.c libunwind.o
	gives a working one, with libunwind.o extracted from a plain
	earmv7hf libc.a
>How-To-Repeat:
	see above.
>Fix:
	unkown.