[PATCH] Fix PR gcov-profile/54487 (profiledbootstrap intermittent failures) (issue6496113)

[Teresa Johnson]

On Wed, Sep 12, 2012 at 1:54 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Sep 12, 2012 at 01:45:12PM -0700, Teresa Johnson wrote:
>> This fixes PR gcov-profile/54487 where the gcda files were not locked
>> by the profile-use read, enabling writes by other instrumented compiles
>> to change the profile in the middle of the profile use read. The GCOV_LOCKED
>> macro was not set because it was guarded by HOST_HAS_F_SETLKW, which was
>> never set. The fix is to add a compile test in the configure to set it.
>>
>> Tested with bootstrap and profiledbootstrap on x86_64-unknown-linux-gnu.
>> Ok for trunk?
>>
>> Thanks,
>> Teresa
>>
>> 2012-09-12  Teresa Johnson  <tejohnson@google.com>
>>
>
> Please include
>         PR gcov-profile/54487
> here in the ChangeLog entry.
>
>>       * configure.ac(HOST_HAS_F_SETLKW): Set based on compile
>
> Space before (.
>
>>       test using F_SETLKW with fcntl.
>>       * configure, config.in: Regenerate.
>>
>> --- configure.ac      (revision 191225)
>> +++ configure.ac      (working copy)
>> @@ -1159,6 +1159,16 @@ if test $gcc_cv_type_clock_t = yes; then
>>    [Define if <time.h> defines clock_t.])
>>  fi
>>
>> +# Check if F_SETLKW is supported by fcntl.
>> +AC_CACHE_CHECK(for F_SETLKW, ac_cv_f_setlkw, [
>> +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
>> +#include "fcntl.h"
>
> Please use
> #include <fcntl.h>
> instead.
>
>> +]], [[struct flock fl; fl.l_whence = 0; fl.l_start = 0; fl.l_len = 0; fl.l_pid = 0; return fcntl (1, F_SETLKW, &fl);]])],[ac_cv_f_setlkw=yes],[ac_cv_f_setlkw=no])])
>
> And split this overlong line, there is no reason why you can't use a newline
> e.g. after every ; in the test proglet.
>
>> +if test $ac_cv_f_setlkw = yes; then
>> +  AC_DEFINE(HOST_HAS_F_SETLKW, 1,
>> +  [Define if F_SETLKW supported by fcntl.])
>> +fi
>> +
>>  # Restore CFLAGS, CXXFLAGS from before the gcc_AC_NEED_DECLARATIONS tests.
>>  CFLAGS="$saved_CFLAGS"
>>  CXXFLAGS="$saved_CXXFLAGS"
>
> Ok for trunk with those changes, IMHO it would be worthwhile to put this
> into 4.7 too, I've seen several unexplained profiledbootstrap errors on
> that branch in the past already when using make -jN with high N.

Ok, thanks. I will fix the issues you pointed out above and retest
before committing. I'll prepare a backport patch for 4.7 as well.

Teresa

>
>         Jakub



-- 
Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413