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author | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2015-08-19 13:08:45 +0200 |
---|---|---|
committer | Peter Korsgaard <peter@korsgaard.com> | 2015-08-19 17:45:51 +0200 |
commit | 97e9db4332aeb58c5b83536426906df942573d4d (patch) | |
tree | e08a257a3939a994b89420493fb75d3bca7847f6 /package/libpthsem | |
parent | d9b6ad84f1787cd36dd4a346a737e5de7f4a25ee (diff) |
libpthsem: fix setjmp/longjmp detection
libpthsem has been affected since quite a while by build issues, but
occuring only on Nathaniel Roach's autobuilder. The failure message
is:
error: #error "Unsupported Linux (g)libc version and/or platform"
This message comes from pth_mctx.c file, which implements five methods
for machine context initialization:
VARIANT 1: THE STANDARDIZED SVR4/SUSv2 APPROACH
VARIANT 2: THE SIGNAL STACK TRICK
VARIANT 3: LINUX SPECIFIC JMP_BUF FIDDLING
VARIANT 4: INTERACTIVE SPECIFIC JMP_BUF FIDDLING
VARIANT 5: WIN32 SPECIFIC JMP_BUF FIDDLING
The "Unsupported (g)libc version and/or platform" only appears when
"VARIANT 4" is used, since VARIANT 4 only supports a very limited
number of platforms. So when building with Nathaniel's autobuilder,
VARIANT 4 is chosen.
However, when you build libpthsem on some other machine than
Nathaniel's autobuilder, VARIANT 2 is chosen, and works regardless of
the glibc version or architecture.
VARIANT 2 is chosen when:
!PTH_MCTX_DSP(sjljlx) &&\
!PTH_MCTX_DSP(sjljisc) &&\
!PTH_MCTX_DSP(sjljw32)
On both Nathaniel's autobuilder, and on a different machine, the
PTH_MCTX_MTH macro gives sjlj:
#define PTH_MCTX_MTH_use PTH_MCTX_MTH_sjlj
However, on a "normal" machine, the PTH_MCTX_DSP macro gives ssjlj:
#define PTH_MCTX_DSP_use PTH_MCTX_DSP_ssjlj
While on Nathaniel's autobuilder, it gives:
#define PTH_MCTX_DSP_use PTH_MCTX_DSP_sjljlx
This explains why VARIANT 4 is being used on Nathaniel's autobuilder,
while VARIANT 2 is used when building on other platforms.
The decision of the value for PTH_MCTX_DSP is derived as follows in
configure.ac:
AC_CHECK_SJLJ(sjlj=yes, sjlj=no, sjlj_type)
[...]
elif test ".$sjlj" = .yes; then
mctx_mth=sjlj
mctx_dsp=$sjlj_type
[...]
AC_DEFINE_UNQUOTED(PTH_MCTX_DSP_use, [PTH_MCTX_DSP_$mctx_dsp], [define for machine context dispatching])
So basically, the value of PTH_MCTX_DSP is $sjlj_type, as returned by
the AC_CHECK_SJLJ autoconf macro, implemented in
acinclude.m4. However, reading this macro is quite informative: it
does a number of tests that are not cross-compile
friendly. Especially, it looks at the kernel version with 'uname -r'
to decide whether the Linux system is braindead or not. If the system
runs a 2.2.x kernel or newer 2.x, or a 3.x kernel, everything is fine,
the system is not braindead, and sjlj_type is set to ssjlj. However,
if the build system runs a 4.x kernel, then it is considered as
braindead, and sjlj_type is set to sjljlx.
And indeed, Nathaniel's autobuilder is running a 4.x kernel, while all
other autobuilders run 2.x or 3.x kernels.
Since for all sane Linux systems, this AC_CHECK_SJLJ macro concludes
that the setjmp/longtmp type is ssjlj, this commit takes the simplest
route of forcing this value, skipping the broken detection.
Note that we're overriding ac_cv_check_sjlj instead of using the
--with-mctx-* options, since the latter do not work properly in the
context of Nathaniel's autobuilder, as the broken cross-compilation
tests continue to cause problems.
Fixes:
http://autobuild.buildroot.org/results/3dd/3dd66d70c2e36f2d9fb0a0fe01bbdec009d55067/
and many similar build failures
This patch has been tested by Nathaniel Roach in the context of his
autobuilder instance which was causing the original problem.
Tested-by: Nathaniel Roach <nroach44@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Diffstat (limited to 'package/libpthsem')
-rw-r--r-- | package/libpthsem/libpthsem.mk | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/package/libpthsem/libpthsem.mk b/package/libpthsem/libpthsem.mk index f9f6f7181..b8a3d7d56 100644 --- a/package/libpthsem/libpthsem.mk +++ b/package/libpthsem/libpthsem.mk @@ -13,6 +13,20 @@ LIBPTHSEM_AUTORECONF = YES LIBPTHSEM_INSTALL_STAGING = YES LIBPTHSEM_CONFIG_SCRIPTS = pthsem-config +# Force the setjmp/longjmp detection, because the test being done in +# the AC_CHECK_SJLJ macro is not cross-compilation safe: it checks the +# running kernel with 'uname -r', and checks the C library version by +# looking at /usr/include/features.h. In terms of kernel version, it +# assumes any version later than 2.2.x is fine, except that it doesn't +# recognize 4.x as a valid kernel version, recognizing such systems as +# "braindead" and therefore falling back to the 'sjljlx' value for +# ac_cv_check_sjlj. In terms of C library version, it wants +# __GLIBC_MINOR to be at least 1. Since both conditions are true for +# all Buildroot systems, we can simply force the setjmp/longjmp +# detection to ssjlj. +LIBPTHSEM_CONF_ENV += \ + ac_cv_check_sjlj=ssjlj + ifeq ($(BR2_PACKAGE_LIBPTHSEM_COMPAT),y) LIBPTHSEM_CONF_OPTS += --enable-compat LIBPTHSEM_CONFIG_SCRIPTS += pth-config |