Skip to contentSkip to conversation

boost: revert b20c5ca3b8c5b180a6ee87556d0c87d474e86cde

PATCH New Fabrice Fontaine 3 participants 6 messages Aug 20, 2018

lore
Share & tools
lore

Fabrice Fontaine

author
#0 lore raw

PATCH 1/2 boost: revert b20c5ca3b8c5b180a6ee87556d0c87d474e86cde

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 <[email protected]>
---
 package/boost/Config.in | 1 -
 1 file changed, 1 deletion(-)
package/boost/Config.in +0 -1
index 965d198ebf..beddc8280c 100644
@@ -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.
Signature · 1 line
2.14.1
author
#1 lore raw

PATCH 2/2 boost: context needs C++11

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 <[email protected]>
---
 package/boost/boost.mk | 5 +++++
 1 file changed, 5 insertions(+)
package/boost/boost.mk +5 -0
index 14f6162003..a09dd3cf45 100644
@@ -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
Signature · 1 line
2.14.1
#2 lore raw

PATCH 2/2 boost: context needs C++11

Hello,

Quoted 17 lines · 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 <[email protected]>
---
 package/boost/boost.mk | 5 +++++
 1 file changed, 5 insertions(+)
package/boost/boost.mk +0 -0
index 14f6162003..a09dd3cf45 100644

package/boost/boost.mk else · line 67

Quoted 7 lines
package/boost/boost.mk +4 -0
@@ -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

Signature · 3 lines
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
#3 lore raw

PATCH 2/2 boost: context needs C++11

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

Quoted 2 lines

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

author
#4 lore raw

PATCH 2/2 boost: context needs C++11

In reply to Thomas Petazzoni

Dear Thomas,

Le lun. 20 ao?t 2018 ? 22:51, Thomas Petazzoni <[email protected]> a ?crit :

Quoted 25 lines

Hello,

Quoted 5 lines · 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

Quoted 1 line

-

http://autobuild.buildroot.net/results/99f1a255b78a973faeb8bf3b94d78efc54426a8b

Quoted 14 lines
Signed-off-by Fabrice Fontaine <[email protected]>
---
 package/boost/boost.mk | 5 +++++
 1 file changed, 5 insertions(+)
package/boost/boost.mk +0 -0
index 14f6162003..a09dd3cf45 100644
@@ -61,6 +61,11 @@ else
 BOOST_FLAGS += --without-icu
 endif
Quoted 7 lines

package/boost/boost.mk else · line 67

Quoted 4 lines
package/boost/boost.mk +4 -0
+# 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, ...)

Quoted 2 lines

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.

Quoted 3 lines

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.

Quoted 3 lines

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.

Quoted 9 lines

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.

Quoted 8 lines

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>

#5 lore raw

PATCH 2/2 boost: context needs C++11

Hello Fabrice,

Quoted 4 lines · Fabrice Fontaine
Quoted 2 lines

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.

Quoted 6 lines
Quoted 2 lines

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.

Quoted 8 lines
Quoted 3 lines

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.

Quoted 1 line
Quoted 4 lines
Quoted 2 lines

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

Signature · 3 lines
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com