acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t.
2015-03-18 Jonathan Wakely <jwakely@redhat.com> Torvald Riegel <triegel@redhat.com> * acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t. * config.h.in: Regenerate. * configure: Regenerate. * include/std/shared_mutex: Check _GLIBCXX_USE_PTHREAD_RWLOCK_T. (shared_timed_mutex::_M_rwlock): Use PTHREAD_RWLOCK_INITIALIZER. (shared_timed_mutex::lock_shared()): Retry on EAGAIN. (shared_timed_mutex::try_lock_shared_until()): Retry on EAGAIN and EDEADLK. Co-Authored-By: Torvald Riegel <triegel@redhat.com> From-SVN: r221484
This commit is contained in:
Jonathan Wakely
Jonathan Wakely
parent
41cee85a34
commit
5e0216f173
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@ -1,3 +1,15 @@
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2015-03-18 Jonathan Wakely <jwakely@redhat.com>
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Torvald Riegel <triegel@redhat.com>
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* acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t.
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* config.h.in: Regenerate.
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* configure: Regenerate.
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* include/std/shared_mutex: Check _GLIBCXX_USE_PTHREAD_RWLOCK_T.
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(shared_timed_mutex::_M_rwlock): Use PTHREAD_RWLOCK_INITIALIZER.
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(shared_timed_mutex::lock_shared()): Retry on EAGAIN.
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(shared_timed_mutex::try_lock_shared_until()): Retry on EAGAIN and
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EDEADLK.
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2015-03-17 Jonathan Wakely <jwakely@redhat.com>
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* libsupc++/nested_exception.h: Do not try to derive from final
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@ -3563,6 +3563,13 @@ AC_DEFUN([GLIBCXX_CHECK_GTHREADS], [
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if test x"$ac_has_gthreads" = x"yes"; then
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AC_DEFINE(_GLIBCXX_HAS_GTHREADS, 1,
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[Define if gthreads library is available.])
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# Also check for pthread_rwlock_t for std::shared_timed_mutex in C++14
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AC_CHECK_TYPE([pthread_rwlock_t],
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[AC_DEFINE([_GLIBCXX_USE_PTHREAD_RWLOCK_T], 1,
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[Define if POSIX read/write locks are available in <gthr.h>.])],
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[],
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[#include "gthr.h"])
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fi
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CXXFLAGS="$ac_save_CXXFLAGS"
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@ -851,6 +851,9 @@
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/* Define if pthreads_num_processors_np is available in <pthread.h>. */
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#undef _GLIBCXX_USE_PTHREADS_NUM_PROCESSORS_NP
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/* Define if POSIX read/write locks are available in <gthr.h>. */
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#undef _GLIBCXX_USE_PTHREAD_RWLOCK_T
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/* Define if /dev/random and /dev/urandom are available for the random_device
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of TR1 (Chapter 5.1). */
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#undef _GLIBCXX_USE_RANDOM_TR1
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@ -2498,6 +2498,60 @@ $as_echo "$ac_res" >&6; }
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eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
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} # ac_fn_c_check_type
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# ac_fn_cxx_check_type LINENO TYPE VAR INCLUDES
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# ---------------------------------------------
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# Tests whether TYPE exists after having included INCLUDES, setting cache
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# variable VAR accordingly.
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ac_fn_cxx_check_type ()
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{
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as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
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$as_echo_n "checking for $2... " >&6; }
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if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
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$as_echo_n "(cached) " >&6
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else
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eval "$3=no"
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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$4
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int
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main ()
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{
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if (sizeof ($2))
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return 0;
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;
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return 0;
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}
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_ACEOF
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if ac_fn_cxx_try_compile "$LINENO"; then :
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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$4
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int
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main ()
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{
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if (sizeof (($2)))
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return 0;
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;
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return 0;
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}
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_ACEOF
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if ac_fn_cxx_try_compile "$LINENO"; then :
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else
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eval "$3=yes"
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fi
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rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
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fi
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rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
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fi
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eval ac_res=\$$3
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
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$as_echo "$ac_res" >&6; }
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eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
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} # ac_fn_cxx_check_type
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cat >config.log <<_ACEOF
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This file contains any messages produced by compilers while
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running configure, to aid debugging if configure makes a mistake.
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@ -11539,7 +11593,7 @@ else
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lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
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lt_status=$lt_dlunknown
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cat > conftest.$ac_ext <<_LT_EOF
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#line 11542 "configure"
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#line 11596 "configure"
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#include "confdefs.h"
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#if HAVE_DLFCN_H
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@ -11645,7 +11699,7 @@ else
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lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
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lt_status=$lt_dlunknown
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cat > conftest.$ac_ext <<_LT_EOF
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#line 11648 "configure"
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#line 11702 "configure"
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#include "confdefs.h"
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#if HAVE_DLFCN_H
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@ -15065,7 +15119,7 @@ fi
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#
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# Fake what AC_TRY_COMPILE does. XXX Look at redoing this new-style.
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cat > conftest.$ac_ext << EOF
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#line 15068 "configure"
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#line 15122 "configure"
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struct S { ~S(); };
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void bar();
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void foo()
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@ -15417,7 +15471,7 @@ $as_echo "$glibcxx_cv_atomic_long_long" >&6; }
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# Fake what AC_TRY_COMPILE does.
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cat > conftest.$ac_ext << EOF
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#line 15420 "configure"
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#line 15474 "configure"
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int main()
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{
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typedef bool atomic_type;
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@ -15452,7 +15506,7 @@ $as_echo "$glibcxx_cv_atomic_bool" >&6; }
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rm -f conftest*
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cat > conftest.$ac_ext << EOF
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#line 15455 "configure"
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#line 15509 "configure"
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int main()
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{
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typedef short atomic_type;
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@ -15487,7 +15541,7 @@ $as_echo "$glibcxx_cv_atomic_short" >&6; }
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rm -f conftest*
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cat > conftest.$ac_ext << EOF
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#line 15490 "configure"
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#line 15544 "configure"
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int main()
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{
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// NB: _Atomic_word not necessarily int.
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@ -15523,7 +15577,7 @@ $as_echo "$glibcxx_cv_atomic_int" >&6; }
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rm -f conftest*
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cat > conftest.$ac_ext << EOF
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#line 15526 "configure"
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#line 15580 "configure"
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int main()
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{
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typedef long long atomic_type;
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@ -15602,7 +15656,7 @@ $as_echo "$as_me: WARNING: Performance of certain classes will degrade as a resu
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# unnecessary for this test.
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cat > conftest.$ac_ext << EOF
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#line 15605 "configure"
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#line 15659 "configure"
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int main()
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{
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_Decimal32 d1;
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@ -15644,7 +15698,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
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# unnecessary for this test.
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cat > conftest.$ac_ext << EOF
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#line 15647 "configure"
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#line 15701 "configure"
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template<typename T1, typename T2>
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struct same
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{ typedef T2 type; };
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@ -15678,7 +15732,7 @@ $as_echo "$enable_int128" >&6; }
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rm -f conftest*
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cat > conftest.$ac_ext << EOF
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#line 15681 "configure"
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#line 15735 "configure"
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template<typename T1, typename T2>
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struct same
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{ typedef T2 type; };
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@ -78786,6 +78840,16 @@ $as_echo "$ac_has_gthreads" >&6; }
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$as_echo "#define _GLIBCXX_HAS_GTHREADS 1" >>confdefs.h
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# Also check for pthread_rwlock_t for std::shared_timed_mutex in C++14
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ac_fn_cxx_check_type "$LINENO" "pthread_rwlock_t" "ac_cv_type_pthread_rwlock_t" "#include \"gthr.h\"
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"
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if test "x$ac_cv_type_pthread_rwlock_t" = x""yes; then :
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$as_echo "#define _GLIBCXX_USE_PTHREAD_RWLOCK_T 1" >>confdefs.h
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fi
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fi
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CXXFLAGS="$ac_save_CXXFLAGS"
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@ -57,10 +57,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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/// shared_timed_mutex
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class shared_timed_mutex
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{
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#if defined(__GTHREADS_CXX0X)
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#ifdef _GLIBCXX_USE_PTHREAD_RWLOCK_T
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typedef chrono::system_clock __clock_t;
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pthread_rwlock_t _M_rwlock;
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#ifdef PTHREAD_RWLOCK_INITIALIZER
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pthread_rwlock_t _M_rwlock = PTHREAD_RWLOCK_INITIALIZER;
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public:
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shared_timed_mutex() = default;
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~shared_timed_mutex() = default;
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#else
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pthread_rwlock_t _M_rwlock;
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public:
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shared_timed_mutex()
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@ -82,6 +89,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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// Errors not handled: EBUSY, EINVAL
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_GLIBCXX_DEBUG_ASSERT(__ret == 0);
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}
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#endif
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shared_timed_mutex(const shared_timed_mutex&) = delete;
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shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
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@ -165,12 +173,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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void
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lock_shared()
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{
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int __ret = pthread_rwlock_rdlock(&_M_rwlock);
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int __ret;
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// We retry if we exceeded the maximum number of read locks supported by
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// the POSIX implementation; this can result in busy-waiting, but this
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// is okay based on the current specification of forward progress
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// guarantees by the standard.
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do
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__ret = pthread_rwlock_rdlock(&_M_rwlock);
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while (__ret == EAGAIN);
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if (__ret == EDEADLK)
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__throw_system_error(int(errc::resource_deadlock_would_occur));
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if (__ret == EAGAIN)
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// Maximum number of read locks has been exceeded.
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__throw_system_error(int(errc::device_or_resource_busy));
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// Errors not handled: EINVAL
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_GLIBCXX_DEBUG_ASSERT(__ret == 0);
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}
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@ -210,11 +222,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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static_cast<long>(__ns.count())
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};
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int __ret = pthread_rwlock_timedrdlock(&_M_rwlock, &__ts);
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// If the maximum number of read locks has been exceeded, or we would
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// deadlock, we just fail to acquire the lock. Unlike for lock(),
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// we are not allowed to throw an exception.
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if (__ret == ETIMEDOUT || __ret == EAGAIN || __ret == EDEADLK)
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int __ret;
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// Unlike for lock(), we are not allowed to throw an exception so if
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// the maximum number of read locks has been exceeded, or we would
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// deadlock, we just try to acquire the lock again (and will time out
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// eventually).
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// In cases where we would exceed the maximum number of read locks
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// throughout the whole time until the timeout, we will fail to
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// acquire the lock even if it would be logically free; however, this
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// is allowed by the standard, and we made a "strong effort"
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// (see C++14 30.4.1.4p26).
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// For cases where the implementation detects a deadlock we
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// intentionally block and timeout so that an early return isn't
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// mistaken for a spurious failure, which might help users realise
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// there is a deadlock.
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do
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__ret = pthread_rwlock_timedrdlock(&_M_rwlock, &__ts);
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while (__ret == EAGAIN || __ret == EDEADLK);
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if (__ret == ETIMEDOUT)
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return false;
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// Errors not handled: EINVAL
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_GLIBCXX_DEBUG_ASSERT(__ret == 0);
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unlock();
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}
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#else // defined(__GTHREADS_CXX0X)
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#else // ! _GLIBCXX_USE_PTHREAD_RWLOCK_T
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#if _GTHREAD_USE_MUTEX_TIMEDLOCK
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struct _Mutex : mutex, __timed_mutex_impl<_Mutex>
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_M_gate1.notify_one();
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}
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}
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#endif // !defined(__GTHREADS_CXX0X)
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#endif // ! _GLIBCXX_USE_PTHREAD_RWLOCK_T
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};
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#endif // _GLIBCXX_HAS_GTHREADS
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