[Buildroot] [PATCH 2/2] package/pixman: fix build failure due to gcc bug 101737

[Giulio Benetti]

Hi Arnout, Thomas,

> Il giorno 4 ago 2021, alle ore 22:28, Arnout Vandecappelle <arnout at mind.be> ha scritto:
> 
>  Hi Giulio,
> 
>> On 03/08/2021 10:42, Giulio Benetti wrote:
>> The pixman package exhibits gcc bug 101737 when built for the SH4
>> architecture with optimization enabled, which causes a build failure.
>> 
>> As done for other packages in Buildroot work around this gcc bug by
>> setting optimization to -O0 if BR2_TOOLCHAIN_HAS_GCC_BUG_101737=y.
>> Also let's add PIXMAN_CFLAGS and pass the Codesourcery work around CFLAGS
>> to it for consistency like we do for the rest of the packages.
>> 
>> Fixes:
>> http://autobuild.buildroot.net/results/b20/b20869bbb48edb1f0a847ea9e2e1a0462d6350be/
>> 
>> Signed-off-by: Giulio Benetti <giulio.benetti at benettiengineering.com>
>> ---
>> package/pixman/pixman.mk | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>> 
>> diff --git a/package/pixman/pixman.mk b/package/pixman/pixman.mk
>> index d99005ecb7..6fab539593 100644
>> --- a/package/pixman/pixman.mk
>> +++ b/package/pixman/pixman.mk
>> @@ -44,12 +44,20 @@ ifneq ($(BR2_iwmmxt),y)
>> PIXMAN_CONF_OPTS += --disable-arm-iwmmxt
>> endif
>> 
>> +PIXMAN_CFLAGS = $(TARGET_CFLAGS)
>> +
>> # toolchain gets confused about TLS access through GOT (PIC), so disable TLS
>> # movhi    r4, %got_hiadj(%tls_ldo(fast_path_cache))
>> # {standard input}:172: Error: bad expression
>> ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_NIOSII),y)
>> -PIXMAN_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -DPIXMAN_NO_TLS"
>> +PIXMAN_CFLAGS += -DPIXMAN_NO_TLS
>> +endif
>> +
>> +ifeq ($(BR2_TOOLCHAIN_HAS_GCC_BUG_101737),y)
> 
> I believe Thomas's experiments showed that it only occurs under -Os. So I think
> we should do this conditionally under BR2_OPTIMIZE_S, and use -O2 rather than -O0.

Yes, you’re right, but at a certain point, if I remember correctly, we’ve decided to uniform this kind work-arounds using -O0,
 indeed some other gcc bug could be solved differently but we kept -O0 way to have a “standard” solution.

What do you think about it?

Otherwise I do as you’ve described above, no problem.

Best regards
Giulio Benetti

> 
> 
> Regards,
> Arnout
> 
>> +PIXMAN_CFLAGS += -O0
>> endif
>> 
>> +PIXMAN_CONF_OPTS += CFLAGS="$(PIXMAN_CFLAGS)"
>> +
>> $(eval $(autotools-package))
>> $(eval $(host-autotools-package))
>>