Re: gcc possibly generating invalid assembler

[Michael Jeanson <mjeanson@ubuntu.com>]

On Thu, Apr 13, 2017 at 01:08:59PM +0200, John Paul Adrian Glaubitz wrote:
> 
> I have unsuccessfully been trying to build liburcu on Debian/m68k. After
> adding "m68k" as a detected architecture in configure.ac, the build
> fails with the assembler generating syntax error messages [1]:
> 
> gcc -DHAVE_CONFIG_H -I. -I../.. -I../../urcu   -Wdate-time -D_FORTIFY_SOURCE=2 -I../.. -I../.. -I../../tests/common -g -g -O2
> -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -pthread -c -o test_urcu_defer.o test_urcu_defer.c
> /tmp/ccXHVXOc.s: Assembler messages:
> /tmp/ccXHVXOc.s:312: Error: syntax error -- statement `add.l %d1,nr_writes@TLSLE+4(%a0)' ignored
> /tmp/ccXHVXOc.s:440: Error: syntax error -- statement `add.l %d1,nr_writes@TLSLE+4(%a0)' ignored

The invalid asm is related to Thread Local Storage and liburcu has a
compat layer that can be enabled at configure for platforms that don't
have it.

With './configure --disable-compiler-tls' the build succeeds and the
regression test suite completes without having to disable optimisations.

Hope this helps,

Michael