On 09/27/2014 08:48 PM, Yi Qingliang wrote:

 https://github.com/boostorg/atomic/commit/415db7054723291042e4ff1ffa8fdd5bc8b07163

 Please, see if it helps in your case.

This is probably a good patch to apply to boost 1.56 in OE, but it's too large to qualify as "obvious".  I use neither armv6 hosts nor Boost and am not actively working OE at this time, so I can't verify that it works on the target.  Perhaps you, Dan, or somebody else will be willing to create a recipe patch, validate it, and submit it here.

Peter



On Mon, Sep 1, 2014 at 7:37 PM, Peter A. Bigot <pab@pabigot.com> wrote:
On 08/31/2014 09:31 PM, Yi Qingliang wrote:
then what's your suggestion for now?

 If the s3c6410 is ARMv6 and does not support ARMv6-K instructions, then boost 1.56 does not work for your platform.  Try downgrading to 1.55, or asking the Boost folks for a patch to update boost/atomic/detail/caps_gcc_atomic.hpp so that it supports that architecture, which lacks the byte, half-word, and double-word atomic ldrex/strex instruction variants.

If the s3c6410 does support ARMv6-K instructions, you can try making sure it builds with -march=arvm6k.

I don't know the conditions under which this becomes an OE-Core problem.  It's not a gcc problem.

Peter




On Sat, Aug 30, 2014 at 9:14 AM, Peter A. Bigot <pab@pabigot.com> wrote:
On 08/29/2014 04:18 PM, Dan McGregor wrote:
On 29 August 2014 14:58, Peter A. Bigot <pab@pabigot.com> wrote:
On 08/29/2014 03:36 PM, Dan McGregor wrote:
On 29 August 2014 05:48, Peter A. Bigot <pab@pabigot.com> wrote:
On 08/29/2014 06:28 AM, Yi Qingliang wrote:

hardware: samsung s3c6410

after updated to latest poky, the boost compile fail!

error info:
libs/atomic/src/lockpool.cpp:127:5: error: 'thread_fence' is not a member
of
'boost::atomics::detail'
libs/atomic/src/lockpool.cpp:138:5: error: 'signal_fence' is not a member
of
'boost::atomics::detail'


after dig into it, I found that:
the marco 'BOOST_ATOMIC_FLAG_LOCK_FREE' is 0, so it don't include
'operations_lockfree.hpp' which has 'thread_fence' and 'signal_fence',
but
pthread.h at line 21.

in file 'caps_gcc_atomic.hpp', 'BOOST_ATOMIC_FLAG_LOCK_FREE' is set to
'0',
the author think if '__GCC_ATOMIC_BOOL_LOCK_FREE' is 1, the atomic serial
function gcc provided is not lock free.


This is the sort of GCC internal header indicator that would have changed
value as a result of:


http://cgit.openembedded.org/openembedded-core/commit/meta/recipes-devtools/gcc/gcc-configure-common.inc?id=0ba6ab39f187ecd4261f08e768f365f461384a3a



at the end of 'caps_gcc_atomic.hpp', it defined
'BOOST_ATOMIC_THREAD_FENCE'
as 2.

so the conflict is: BOOST_ATOMIC_THREAD_FENCE and
BOOST_ATOMIC_FLAG_LOCK_FREE

I don't know it is the new poky problem, or the boost problem, any idea?


My guess is that Boost is making assumptions about what the internal GCC
predefined symbols mean that aren't entirely accurate.  There are several
flags that are used in the libstdc++ headers to indicate whether the
compiler is using lock-free instructions.

Boost-1.56 builds without error for my beaglebone target with poky at:

* 669c07d (HEAD, origin/master, origin/HEAD, master/upstream, master/dev)
[Wed Aug 27 14:24:52 2014 +0100] bitbake: build/data: Write out more
complete python run files

so it may have something to do with your target machine.
It absolutely does. I found that armv6 breaks, but armv6zk and newer work.

Interesting.  There are no armv6zk tune features I can see in poky, though
google suggests it applies to the Raspberry Pi.

The problem then must be with the first override in this:

# ARMv6+ adds atomic instructions that affect the ABI in libraries built
# with TUNE_CCARGS in gcc-runtime.  Make the compiler default to a
# compatible architecture.  armv6 and armv7a cover the minimum tune
# features used in OE.
EXTRA_OECONF_append_armv6 = " --with-arch=armv6"
EXTRA_OECONF_append_armv7a = " --with-arch=armv7-a"

ARMv6 has LDREX/STREX, but ARMv6K adds {LD,ST}REX{B,H,D}.  The same problem
addressed above is likely to happen if the libraries are built with armv6k
but the compiler doesn't default to it.

There are no armv6k tune parameters I can locate in poky.  What layers have
the tune configurations that are causing problems?

For me meta-raspberrypi failed to build. Its tuning is -march=armv6
-mtune=arm1176zjf-s by default. I forced it to -march=armv6zk
-mtune=arm1176jzf-s, and that worked.

tl;dr: for now, this can be claimed to be a boost problem, but it may rapidly become an OE problem.

OK, so there's several issues here.

Extracting the predefined symbols from gcc 4.9.1 with:

   arm-poky-linux-gnueabi-g++ -march=armv6 -dM -E -xc++ /dev/null

and similarly with -march=armv6k shows that the values of these atomic-related predefines are different (- = arvm6, + = armv6k):

-#define __GCC_ATOMIC_BOOL_LOCK_FREE 1
-#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 1
+#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
+#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
-#define __GCC_ATOMIC_CHAR_LOCK_FREE 1
+#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
-#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
+#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
-#define __GCC_ATOMIC_SHORT_LOCK_FREE 1
+#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
+#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1

(armv6zk is the same as armv6k for atomic-related capabilities.)

boost/atomic/detail/caps_gcc_atomic.hpp apparently does not provide an implementation of thread_fence or signal_fence for the armv6 configuration, only for the armv6k and later ones.

That's a boost problem.

The fact that -mtune=arm1176jzf-s apparently doesn't enable the armv6k features even though gcc's source code implies it should is an anomaly.  (Check this by substituting -mtune=arm1176jzf-s for -march=armv6 and verifying that the predefined symbols are the same for both configurations.)

If that anomaly is ever resolved, or if meta-raspberrypi chooses to switch to -march=armv6zk, then gcc-configure-common.inc almost certainly need to recognize armv6k as an override distinct from armv6: mutex-related code built for armv6k via gcc-runtime will result in a different ABI from mutex-related code built for armv6 (what gcc will produce for builds that do not use OE's tuning parameters).

If the solution to the boost problem is to change meta-raspberrypi to use -march=armv6k then gcc-configure-common.inc will need to be updated as well.  Probably OE should recognize it as a distinct ARM architecture too.


Peter
--
_______________________________________________
Openembedded-core mailing list
Openembedded-core@lists.openembedded.org
http://lists.openembedded.org/mailman/listinfo/openembedded-core