[Buildroot] [PATCH 1/2] boost: revert b20c5ca3b8c5b180a6ee87556d0c87d474e86cde

[Buildroot] [PATCH 1/2] boost: revert b20c5ca3b8c5b180a6ee87556d0c87d474e86cde

[Fabrice Fontaine]

mutex is available on gcc <= 4.7.x, the issue is that boost does not
correctly detect it because -std=c++11 is missing

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 package/boost/Config.in | 1 -
 1 file changed, 1 deletion(-)

diff --git a/package/boost/Config.in b/package/boost/Config.in
index 965d198ebf..beddc8280c 100644
--- a/package/boost/Config.in
+++ b/package/boost/Config.in
@@ -83,7 +83,6 @@ config BR2_PACKAGE_BOOST_CONTEXT
 	bool "boost-context"
 	depends on BR2_PACKAGE_BOOST_CONTEXT_ARCH_SUPPORTS
 	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735
-	select BR2_PACKAGE_BOOST_THREAD if !BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
 	help
 	  C++11 context switching library.
 
-- 
2.14.1

[Buildroot] [PATCH 2/2] boost: context needs C++11

[Fabrice Fontaine]

Without this flag, mutex is not always correctly detected with gcc 4.x
or 5.x. As a result, boost_thread is wrongly selected by boost_context.

Fixes:
 - http://autobuild.buildroot.net/results/fb046c04fe18bec973d120e4ab33971f32ba5769
 - http://autobuild.buildroot.net/results/99f1a255b78a973faeb8bf3b94d78efc54426a8b

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 package/boost/boost.mk | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/package/boost/boost.mk b/package/boost/boost.mk
index 14f6162003..a09dd3cf45 100644
--- a/package/boost/boost.mk
+++ b/package/boost/boost.mk
@@ -61,6 +61,11 @@ else
 BOOST_FLAGS += --without-icu
 endif
 
+# boost-context needs C++11
+ifeq ($(BR2_PACKAGE_BOOST_CONTEXT),y)
+BOOST_TARGET_CXXFLAGS += -std=c++11
+endif
+
 ifeq ($(BR2_PACKAGE_BOOST_IOSTREAMS),y)
 BOOST_DEPENDENCIES += bzip2 zlib
 endif
-- 
2.14.1

[Buildroot] [PATCH 2/2] boost: context needs C++11

[Thomas Petazzoni]

Hello,

On Mon, 20 Aug 2018 18:55:55 +0200, Fabrice Fontaine wrote:
> Without this flag, mutex is not always correctly detected with gcc 4.x
> or 5.x. As a result, boost_thread is wrongly selected by boost_context.
> 
> Fixes:
>  - http://autobuild.buildroot.net/results/fb046c04fe18bec973d120e4ab33971f32ba5769
>  - http://autobuild.buildroot.net/results/99f1a255b78a973faeb8bf3b94d78efc54426a8b
> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> ---
>  package/boost/boost.mk | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/package/boost/boost.mk b/package/boost/boost.mk
> index 14f6162003..a09dd3cf45 100644
> --- a/package/boost/boost.mk
> +++ b/package/boost/boost.mk
> @@ -61,6 +61,11 @@ else
>  BOOST_FLAGS += --without-icu
>  endif
>  
> +# boost-context needs C++11
> +ifeq ($(BR2_PACKAGE_BOOST_CONTEXT),y)
> +BOOST_TARGET_CXXFLAGS += -std=c++11
> +endif

I was about to apply, but... C++11 requires at least gcc 4.8 or 4.9
depending on the features being used, and I don't see any dependency on
a gcc version in the definition of BR2_PACKAGE_BOOST_CONTEXT. There are
also other Boost options that say they are related to C++11.

Don't we have a problem with gcc 4.7 or older compilers ?

https://git.buildroot.org/buildroot/tree/support/config-fragments/autobuild/powerpc-ctng_e500v2-linux-gnuspe.config
has a 4.7 compiler.

I'm not sure we have a gcc 4.6 compiler. Perhaps we should add that to
the autobuilders.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

[Buildroot] [PATCH 2/2] boost: context needs C++11

[Bernd Kuhls]

Am Mon, 20 Aug 2018 22:50:58 +0200 schrieb Thomas Petazzoni:

> I'm not sure we have a gcc 4.6 compiler. Perhaps we should add that to
> the autobuilders.

Hi Thomas,

sounds good, and while being at it do we have a gcc-8.2 toolchain and
another glibc-2.28-based toolchain for the autobuilders as well?

Regards, Bernd

[Buildroot] [PATCH 2/2] boost: context needs C++11

[Fabrice Fontaine]

Dear Thomas,

Le lun. 20 ao?t 2018 ? 22:51, Thomas Petazzoni <thomas.petazzoni@bootlin.com>
a ?crit :

> Hello,
>
> On Mon, 20 Aug 2018 18:55:55 +0200, Fabrice Fontaine wrote:
> > Without this flag, mutex is not always correctly detected with gcc 4.x
> > or 5.x. As a result, boost_thread is wrongly selected by boost_context.
> >
> > Fixes:
> >  -
> http://autobuild.buildroot.net/results/fb046c04fe18bec973d120e4ab33971f32ba5769
> >  -
> http://autobuild.buildroot.net/results/99f1a255b78a973faeb8bf3b94d78efc54426a8b
> >
> > Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> > ---
> >  package/boost/boost.mk | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/package/boost/boost.mk b/package/boost/boost.mk
> > index 14f6162003..a09dd3cf45 100644
> > --- a/package/boost/boost.mk
> > +++ b/package/boost/boost.mk
> > @@ -61,6 +61,11 @@ else
> >  BOOST_FLAGS += --without-icu
> >  endif
> >
> > +# boost-context needs C++11
> > +ifeq ($(BR2_PACKAGE_BOOST_CONTEXT),y)
> > +BOOST_TARGET_CXXFLAGS += -std=c++11
> > +endif
>
> I was about to apply, but... C++11 requires at least gcc 4.8 or 4.9
>
That's not right, C++11 requires at least gcc 4.7 (see libcec, jsoncpp,
poppler, yaml-cpp, ...)

> depending on the features being used, and I don't see any dependency on
> a gcc version in the definition of BR2_PACKAGE_BOOST_CONTEXT.

But you're right, we should update first patch to select
BR2_PACKAGE_BOOST_THREAD if gcc version is lower than 4.7 (and not 4.8). I
will send a v2.

> There are
> also other Boost options that say they are related to C++11.
>
I did not check if we should add -std=c++11 for those other boost options.
At least, it does not cause any build failures but perhaps some features
are wrongly disabled with some older versions of gcc.

>
> Don't we have a problem with gcc 4.7 or older compilers ?
>
std=c++11 works with gcc 4.7, I did not take time to test with older
versions.

>
>
> https://git.buildroot.org/buildroot/tree/support/config-fragments/autobuild/powerpc-ctng_e500v2-linux-gnuspe.config
> has a 4.7 compiler.
>
>  I'm not sure we have a gcc 4.6 compiler. Perhaps we should add that to

> the autobuilders.
>
Yes, it's a good idea.

>
> Best regards,
>
> Thomas
> --
> Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
> Embedded Linux and Kernel engineering
> https://bootlin.com

Best Regards,

Fabrice
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.busybox.net/pipermail/buildroot/attachments/20180820/69f4d010/attachment.html>

[Buildroot] [PATCH 2/2] boost: context needs C++11

[Thomas Petazzoni]

Hello Fabrice,

On Mon, 20 Aug 2018 23:33:14 +0200, Fabrice Fontaine wrote:

> > I was about to apply, but... C++11 requires at least gcc 4.8 or 4.9
> >  
> That's not right, C++11 requires at least gcc 4.7 (see libcec, jsoncpp,
> poppler, yaml-cpp, ...)

OK. It in fact depends on which C++11 features you depend on, see
https://gcc.gnu.org/projects/cxx-status.html#cxx11. Some C++11 features
only got added in 4.8.

> > depending on the features being used, and I don't see any dependency on
> > a gcc version in the definition of BR2_PACKAGE_BOOST_CONTEXT.  
> 
> But you're right, we should update first patch to select
> BR2_PACKAGE_BOOST_THREAD if gcc version is lower than 4.7 (and not 4.8). I
> will send a v2.

Well, see above. C++11 support is not as clear-cut as: gcc < 4.7
doesn't have it, gcc >= 4.7 has it.

> > There are
> > also other Boost options that say they are related to C++11.
> >  
> I did not check if we should add -std=c++11 for those other boost options.
> At least, it does not cause any build failures but perhaps some features
> are wrongly disabled with some older versions of gcc.
> 
> >
> > Don't we have a problem with gcc 4.7 or older compilers ?
> >  
> std=c++11 works with gcc 4.7, I did not take time to test with older
> versions.

So what are you going to do ? Add std=c++11 unconditionally, without
knowing if this is going to be accepted by older gcc versions ?

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com