mutex.m4

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# $Id: mutex.m4,v 12.26 2007/05/18 15:08:50 bostic Exp $

# POSIX pthreads tests: inter-process safe and intra-process only.
AC_DEFUN(AM_PTHREADS_SHARED, [
AC_TRY_RUN([
#include <pthread.h>
main() {
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_condattr_setpshared(&condattr, PTHREAD_PROCESS_SHARED) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_mutexattr_setpshared(&mutexattr, PTHREAD_PROCESS_SHARED) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
}], [db_cv_mutex="$1"],,
AC_TRY_LINK([
#include <pthread.h>],[
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_condattr_setpshared(&condattr, PTHREAD_PROCESS_SHARED) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_mutexattr_setpshared(&mutexattr, PTHREAD_PROCESS_SHARED) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
], [db_cv_mutex="$1"]))])
AC_DEFUN(AM_PTHREADS_PRIVATE, [
AC_TRY_RUN([
#include <pthread.h>
main() {
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
}], [db_cv_mutex="$1"],,
AC_TRY_LINK([
#include <pthread.h>],[
	pthread_cond_t cond;
	pthread_mutex_t mutex;
	pthread_condattr_t condattr;
	pthread_mutexattr_t mutexattr;
	exit (
	pthread_condattr_init(&condattr) ||
	pthread_mutexattr_init(&mutexattr) ||
	pthread_cond_init(&cond, &condattr) ||
	pthread_mutex_init(&mutex, &mutexattr) ||
	pthread_mutex_lock(&mutex) ||
	pthread_mutex_unlock(&mutex) ||
	pthread_mutex_destroy(&mutex) ||
	pthread_cond_destroy(&cond) ||
	pthread_condattr_destroy(&condattr) ||
	pthread_mutexattr_destroy(&mutexattr));
], [db_cv_mutex="$1"]))])

# Figure out mutexes for this compiler/architecture.
#
# There are 3 mutex groups in BDB: pthreads-style, test-and-set, or a hybrid
# combination of the two.   We first test for the pthreads-style mutex, and
# then for a test-and-set mutex.
AC_DEFUN(AM_DEFINE_MUTEXES, [

# Mutexes we don't test for, but want the #defines to exist for other ports.
AH_TEMPLATE(HAVE_MUTEX_VMS, [Define to 1 to use VMS mutexes.])
AH_TEMPLATE(HAVE_MUTEX_VXWORKS, [Define to 1 to use VxWorks mutexes.])

AC_CACHE_CHECK([for mutexes], db_cv_mutex, [

orig_libs=$LIBS

db_cv_mutex=no

# Mutexes can be disabled.
if test "$db_cv_build_mutexsupport" = no; then
	db_cv_mutex=disabled;
fi

# User-specified Win32 mutexes (MinGW build)
if test "$db_cv_mingw" = yes; then
	db_cv_mutex=win32/gcc
fi

if test "$db_cv_mutex" = no; then
	# User-specified POSIX or UI mutexes.
	#
	# There are two different reasons to specify mutexes: First, the
	# application is already using one type of mutex and doesn't want
	# to mix-and-match (for example, on Solaris, which has POSIX, UI
	# and LWP mutexes).  Second, the application's POSIX pthreads
	# mutexes don't support inter-process locking, but the application
	# wants to use them anyway (for example, some Linux and *BSD systems).
	#
	# Test for LWP threads before testing for UI/POSIX threads, we prefer
	# them on Solaris, for two reasons: a bug in SunOS 5.7 causes
	# applications to get pwrite, not pwrite64, if they load the C library
	# before the appropriate threads library, e.g., tclsh using dlopen to
	# load the DB library.  Second, LWP mutexes are faster than POSIX
	# pthread mutexes by some amount.
	#
	# Otherwise, test for POSIX threads before UI threads.  There are Linux
	# systems that support a UI compatibility mode, and applications are
	# more likely to be written for POSIX threads than UI threads.

	if test "$db_cv_posixmutexes" = yes; then
		db_cv_mutex=posix_only;
	fi
	if test "$db_cv_uimutexes" = yes; then
		db_cv_mutex=ui_only;
	fi

	# LWP threads: _lwp_XXX
	if test "$db_cv_mutex" = no; then
	AC_TRY_LINK([
	#include <synch.h>],[
		static lwp_mutex_t mi = SHAREDMUTEX;
		static lwp_cond_t ci = SHAREDCV;
		lwp_mutex_t mutex = mi;
		lwp_cond_t cond = ci;
		exit (
		_lwp_mutex_lock(&mutex) ||
		_lwp_mutex_unlock(&mutex));
	], [db_cv_mutex=Solaris/lwp])
	fi

	# POSIX.1 pthreads: pthread_XXX
	#
	# If the user specified we use POSIX pthreads mutexes, and we fail to
	# find the full interface, try and configure for just intra-process
	# support.
	if test "$db_cv_mutex" = no -o "$db_cv_mutex" = posix_only; then
		LIBS="$LIBS -lpthread"
		AM_PTHREADS_SHARED(POSIX/pthreads/library)
		LIBS="$orig_libs"
	fi
	if test "$db_cv_mutex" = no -o "$db_cv_mutex" = posix_only; then
		AM_PTHREADS_SHARED(POSIX/pthreads)
	fi
	if test "$db_cv_mutex" = posix_only; then
		AM_PTHREADS_PRIVATE(POSIX/pthreads/private)
	fi
	if test "$db_cv_mutex" = posix_only; then
		LIBS="$LIBS -lpthread"
		AM_PTHREADS_PRIVATE(POSIX/pthreads/library/private)
		LIBS="$orig_libs"
	fi
	if test "$db_cv_mutex" = posix_only; then
		AC_MSG_ERROR([unable to find POSIX 1003.1 mutex interfaces])
	fi

	# UI threads: thr_XXX
	if test "$db_cv_mutex" = no -o "$db_cv_mutex" = ui_only; then
	LIBS="$LIBS -lthread"
	AC_TRY_LINK([
	#include <thread.h>
	#include <synch.h>],[
		mutex_t mutex;
		cond_t cond;
		int type = USYNC_PROCESS;
		exit (
		mutex_init(&mutex, type, NULL) ||
		cond_init(&cond, type, NULL) ||
		mutex_lock(&mutex) ||
		mutex_unlock(&mutex));
	], [db_cv_mutex=UI/threads/library])
	LIBS="$orig_libs"
	fi
	if test "$db_cv_mutex" = no -o "$db_cv_mutex" = ui_only; then
	AC_TRY_LINK([
	#include <thread.h>
	#include <synch.h>],[
		mutex_t mutex;
		cond_t cond;
		int type = USYNC_PROCESS;
		exit (
		mutex_init(&mutex, type, NULL) ||
		cond_init(&cond, type, NULL) ||
		mutex_lock(&mutex) ||
		mutex_unlock(&mutex));
	], [db_cv_mutex=UI/threads])
	fi
	if test "$db_cv_mutex" = ui_only; then
		AC_MSG_ERROR([unable to find UI mutex interfaces])
	fi

	# We're done testing for pthreads-style mutexes.  Next, check for
	# test-and-set mutexes.  Check first for hybrid implementations,
	# because we check for them even if we've already found a
	# pthreads-style mutex and they're the most common architectures
	# anyway.
	#
	# x86/gcc: FreeBSD, NetBSD, BSD/OS, Linux
	AC_TRY_COMPILE(,[
	#if (defined(i386) || defined(__i386__)) && defined(__GNUC__)
		exit(0);
	#else
		FAIL TO COMPILE/LINK
	#endif
	], [db_cv_mutex="$db_cv_mutex/x86/gcc-assembly"])

	# x86_64/gcc: FreeBSD, NetBSD, BSD/OS, Linux
	AC_TRY_COMPILE(,[
	#if (defined(x86_64) || defined(__x86_64__)) && defined(__GNUC__)
		exit(0);
	#else
		FAIL TO COMPILE/LINK
	#endif
	], [db_cv_mutex="$db_cv_mutex/x86_64/gcc-assembly"])

	# Solaris is one of the systems where we can configure hybrid mutexes.
	# However, we require the membar_enter function for that, and only newer
	# Solaris releases have it.  Check to see if we can configure hybrids.
	AC_TRY_LINK([
	#include <sys/atomic.h>
	#include <sys/machlock.h>],[
		typedef lock_t tsl_t;
		lock_t x;
		_lock_try(&x);
		_lock_clear(&x);
		membar_enter();
	], [db_cv_mutex="$db_cv_mutex/Solaris/_lock_try/membar"])

	# Sparc/gcc: SunOS, Solaris
	AC_TRY_COMPILE(,[
	#if defined(__sparc__) && defined(__GNUC__)
		exit(0);
	#else
		FAIL TO COMPILE/LINK
	#endif
	], [db_cv_mutex="$db_cv_mutex/Sparc/gcc-assembly"])

	# We're done testing for any hybrid mutex implementations.  If we did
	# not find a pthreads-style mutex, but did find a test-and-set mutex,
	# we set db_cv_mutex to "no/XXX" -- clean that up.
	db_cv_mutex=`echo $db_cv_mutex | sed 's/^no\///'`
fi

# If we still don't have a mutex implementation yet, continue testing for a
# test-and-set mutex implementation.

# _lock_try/_lock_clear: Solaris
# On Solaris systems without other mutex interfaces, DB uses the undocumented
# _lock_try _lock_clear function calls instead of either the sema_trywait(3T)
# or sema_wait(3T) function calls.  This is because of problems in those
# interfaces in some releases of the Solaris C library.
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/atomic.h>
#include <sys/machlock.h>],[
	typedef lock_t tsl_t;
	lock_t x;
	_lock_try(&x);
	_lock_clear(&x);
], [db_cv_mutex=Solaris/_lock_try])
fi

# msemaphore: HPPA only
# Try HPPA before general msem test, it needs special alignment.
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/mman.h>],[
#if defined(__hppa)
	typedef msemaphore tsl_t;
	msemaphore x;
	msem_init(&x, 0);
	msem_lock(&x, 0);
	msem_unlock(&x, 0);
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex=HP/msem_init])
fi

# msemaphore: AIX, OSF/1
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/types.h>
#include <sys/mman.h>],[
	typedef msemaphore tsl_t;
	msemaphore x;
	msem_init(&x, 0);
	msem_lock(&x, 0);
	msem_unlock(&x, 0);
	exit(0);
], [db_cv_mutex=UNIX/msem_init])
fi

# ReliantUNIX
if test "$db_cv_mutex" = no; then
LIBS="$LIBS -lmproc"
AC_TRY_LINK([
#include <ulocks.h>],[
	typedef spinlock_t tsl_t;
	spinlock_t x;
	initspin(&x, 1);
	cspinlock(&x);
	spinunlock(&x);
], [db_cv_mutex=ReliantUNIX/initspin])
LIBS="$orig_libs"
fi

# SCO: UnixWare has threads in libthread, but OpenServer doesn't.
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__USLC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex=SCO/x86/cc-assembly])
fi

# abilock_t: SGI
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <abi_mutex.h>],[
	typedef abilock_t tsl_t;
	abilock_t x;
	init_lock(&x);
	acquire_lock(&x);
	release_lock(&x);
], [db_cv_mutex=SGI/init_lock])
fi

# sema_t: Solaris
# The sema_XXX calls do not work on Solaris 5.5.  I see no reason to ever
# turn this test on, unless we find some other platform that uses the old
# POSIX.1 interfaces.
if test "$db_cv_mutex" = DOESNT_WORK; then
AC_TRY_LINK([
#include <synch.h>],[
	typedef sema_t tsl_t;
	sema_t x;
	sema_init(&x, 1, USYNC_PROCESS, NULL);
	sema_wait(&x);
	sema_post(&x);
], [db_cv_mutex=UNIX/sema_init])
fi

# _check_lock/_clear_lock: AIX
if test "$db_cv_mutex" = no; then
AC_TRY_LINK([
#include <sys/atomic_op.h>],[
	int x;
	_check_lock(&x,0,1);
	_clear_lock(&x,0);
], [db_cv_mutex=AIX/_check_lock])
fi

# _spin_lock_try/_spin_unlock: Apple/Darwin
if test "$db_cv_mutex" = no; then
AC_TRY_LINK(,[
	int x;
	_spin_lock_try(&x);
	_spin_unlock(&x);
], [db_cv_mutex=Darwin/_spin_lock_try])
fi

# Tru64/cc
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__alpha) && defined(__DECC)
	exit(0);
#else
	FAIL TO COMPILE/LINK
#endif
], [db_cv_mutex=Tru64/cc-assembly])
fi

# Alpha/gcc
if test "$db_cv_mutex" = no; then
AC_TRY_COMPILE(,[
#if defined(__alpha) && defined(__GNUC__)
	exit(0);
#else
	FAIL TO COMPILE/LINK