[Mesa-dev] [PATCH 2/4] configure.ac: remove explicit -lpthread link

Emil Velikov emil.l.velikov at gmail.com
Sun Jun 4 23:04:00 UTC 2017


From: Emil Velikov <emil.velikov at collabora.com>

As mentioned in last commit - pthread manual suggests using -pthread.
Furthermore, to the best of my knowledge anything built with GCC and
Clang should just work (tm) with the said flag.

AFAICT using the Sun or Intel compiler may need special treatment, but
that is to be confirmed/dismissed.

Cc: Randy Fishel <randy.fishel at oracle.com>
Cc: Niveditha Rau <niveditha.rau at oracle.com>
Cc: Jon Turney <jon.turney at dronecode.org.uk>
Cc: Tim Rowley <timothy.o.rowley at intel.com>
Cc: Bruce Cherniak <bruce.cherniak at intel.com>
Cc: Jeremy Huddleston Sequoia <jeremyhu at apple.com>
Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
---
Ladies and gents,

Please confirm if "-pthread" works on your platform/compiler combos.
If fixup changes are needed, please send over a patch to squash.

Thanks
Emil
---
 configure.ac     |  15 +--
 m4/ax_pthread.m4 | 309 -------------------------------------------------------
 2 files changed, 2 insertions(+), 322 deletions(-)
 delete mode 100644 m4/ax_pthread.m4

diff --git a/configure.ac b/configure.ac
index 1c15eb482f9..2e4264cf592 100644
--- a/configure.ac
+++ b/configure.ac
@@ -825,23 +825,12 @@ AC_CHECK_FUNC([posix_memalign], [DEFINES="$DEFINES -DHAVE_POSIX_MEMALIGN"])
 dnl Check for zlib
 PKG_CHECK_MODULES([ZLIB], [zlib >= $ZLIB_REQUIRED])
 
-dnl Check for pthreads
-AX_PTHREAD
-if test "x$ax_pthread_ok" = xno; then
-    AC_MSG_ERROR([Building mesa on this platform requires pthreads])
-fi
-dnl AX_PTHREADS leaves PTHREAD_LIBS empty for gcc and sets PTHREAD_CFLAGS
-dnl to -pthread, which causes problems if we need -lpthread to appear in
-dnl pkgconfig files.  Since Android doesn't have a pthread lib, this check
-dnl is not valid for that platform.
-if test "x$android" = xno; then
-    test -z "$PTHREAD_LIBS" && PTHREAD_LIBS="-lpthread"
-fi
 dnl According to the manual when using pthreads, one should add -pthread to
 dnl both compile and link-time arguments.
 dnl In practise that should be sufficient for all platforms, since any
 dnl platforms build with GCC and Clang support the flag.
-PTHREAD_LIBS="$PTHREAD_LIBS -pthread"
+PTHREAD_CFLAGS="-pthread"
+PTHREAD_LIBS="-pthread"
 
 dnl pthread-stubs is mandatory on BSD platforms, due to the nature of the
 dnl project. Even then there's a notable issue as described in the project README
diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
deleted file mode 100644
index d90de34d14b..00000000000
--- a/m4/ax_pthread.m4
+++ /dev/null
@@ -1,309 +0,0 @@
-# ===========================================================================
-#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
-#
-# DESCRIPTION
-#
-#   This macro figures out how to build C programs using POSIX threads. It
-#   sets the PTHREAD_LIBS output variable to the threads library and linker
-#   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
-#   flags that are needed. (The user can also force certain compiler
-#   flags/libs to be tested by setting these environment variables.)
-#
-#   Also sets PTHREAD_CC to any special C compiler that is needed for
-#   multi-threaded programs (defaults to the value of CC otherwise). (This
-#   is necessary on AIX to use the special cc_r compiler alias.)
-#
-#   NOTE: You are assumed to not only compile your program with these flags,
-#   but also link it with them as well. e.g. you should link with
-#   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
-#
-#   If you are only building threads programs, you may wish to use these
-#   variables in your default LIBS, CFLAGS, and CC:
-#
-#     LIBS="$PTHREAD_LIBS $LIBS"
-#     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-#     CC="$PTHREAD_CC"
-#
-#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
-#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
-#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
-#
-#   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
-#   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
-#   PTHREAD_CFLAGS.
-#
-#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
-#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
-#   is not found. If ACTION-IF-FOUND is not specified, the default action
-#   will define HAVE_PTHREAD.
-#
-#   Please let the authors know if this macro fails on any platform, or if
-#   you have any other suggestions or comments. This macro was based on work
-#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
-#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
-#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
-#   grateful for the helpful feedback of numerous users.
-#
-#   Updated for Autoconf 2.68 by Daniel Richard G.
-#
-# LICENSE
-#
-#   Copyright (c) 2008 Steven G. Johnson <stevenj at alum.mit.edu>
-#   Copyright (c) 2011 Daniel Richard G. <skunk at iSKUNK.ORG>
-#
-#   This program is free software: you can redistribute it and/or modify it
-#   under the terms of the GNU General Public License as published by the
-#   Free Software Foundation, either version 3 of the License, or (at your
-#   option) any later version.
-#
-#   This program is distributed in the hope that it will be useful, but
-#   WITHOUT ANY WARRANTY; without even the implied warranty of
-#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-#   Public License for more details.
-#
-#   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
-#
-#   As a special exception, the respective Autoconf Macro's copyright owner
-#   gives unlimited permission to copy, distribute and modify the configure
-#   scripts that are the output of Autoconf when processing the Macro. You
-#   need not follow the terms of the GNU General Public License when using
-#   or distributing such scripts, even though portions of the text of the
-#   Macro appear in them. The GNU General Public License (GPL) does govern
-#   all other use of the material that constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the Autoconf
-#   Macro released by the Autoconf Archive. When you make and distribute a
-#   modified version of the Autoconf Macro, you may extend this special
-#   exception to the GPL to apply to your modified version as well.
-
-#serial 18
-
-AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
-AC_DEFUN([AX_PTHREAD], [
-AC_REQUIRE([AC_CANONICAL_HOST])
-AC_LANG_PUSH([C])
-ax_pthread_ok=no
-
-# We used to check for pthread.h first, but this fails if pthread.h
-# requires special compiler flags (e.g. on True64 or Sequent).
-# It gets checked for in the link test anyway.
-
-# First of all, check if the user has set any of the PTHREAD_LIBS,
-# etcetera environment variables, and if threads linking works using
-# them:
-if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
-        AC_TRY_LINK_FUNC(pthread_join, ax_pthread_ok=yes)
-        AC_MSG_RESULT($ax_pthread_ok)
-        if test x"$ax_pthread_ok" = xno; then
-                PTHREAD_LIBS=""
-                PTHREAD_CFLAGS=""
-        fi
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
-fi
-
-# We must check for the threads library under a number of different
-# names; the ordering is very important because some systems
-# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
-# libraries is broken (non-POSIX).
-
-# Create a list of thread flags to try.  Items starting with a "-" are
-# C compiler flags, and other items are library names, except for "none"
-# which indicates that we try without any flags at all, and "pthread-config"
-# which is a program returning the flags for the Pth emulation library.
-
-ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
-
-# The ordering *is* (sometimes) important.  Some notes on the
-# individual items follow:
-
-# pthreads: AIX (must check this before -lpthread)
-# none: in case threads are in libc; should be tried before -Kthread and
-#       other compiler flags to prevent continual compiler warnings
-# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
-# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
-# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
-# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
-# -pthreads: Solaris/gcc
-# -mthreads: Mingw32/gcc, Lynx/gcc
-# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
-#      doesn't hurt to check since this sometimes defines pthreads too;
-#      also defines -D_REENTRANT)
-#      ... -mt is also the pthreads flag for HP/aCC
-# pthread: Linux, etcetera
-# --thread-safe: KAI C++
-# pthread-config: use pthread-config program (for GNU Pth library)
-
-case ${host_os} in
-        solaris*)
-
-        # On Solaris (at least, for some versions), libc contains stubbed
-        # (non-functional) versions of the pthreads routines, so link-based
-        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
-        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
-        # a function called by this macro, so we could check for that, but
-        # who knows whether they'll stub that too in a future libc.)  So,
-        # we'll just look for -pthreads and -lpthread first:
-
-        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
-        ;;
-
-        darwin*)
-        ax_pthread_flags="-pthread $ax_pthread_flags"
-        ;;
-esac
-
-if test x"$ax_pthread_ok" = xno; then
-for flag in $ax_pthread_flags; do
-
-        case $flag in
-                none)
-                AC_MSG_CHECKING([whether pthreads work without any flags])
-                ;;
-
-                -*)
-                AC_MSG_CHECKING([whether pthreads work with $flag])
-                PTHREAD_CFLAGS="$flag"
-                ;;
-
-                pthread-config)
-                AC_CHECK_PROG(ax_pthread_config, pthread-config, yes, no)
-                if test x"$ax_pthread_config" = xno; then continue; fi
-                PTHREAD_CFLAGS="`pthread-config --cflags`"
-                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
-                ;;
-
-                *)
-                AC_MSG_CHECKING([for the pthreads library -l$flag])
-                PTHREAD_LIBS="-l$flag"
-                ;;
-        esac
-
-        save_LIBS="$LIBS"
-        save_CFLAGS="$CFLAGS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-
-        # Check for various functions.  We must include pthread.h,
-        # since some functions may be macros.  (On the Sequent, we
-        # need a special flag -Kthread to make this header compile.)
-        # We check for pthread_join because it is in -lpthread on IRIX
-        # while pthread_create is in libc.  We check for pthread_attr_init
-        # due to DEC craziness with -lpthreads.  We check for
-        # pthread_cleanup_push because it is one of the few pthread
-        # functions on Solaris that doesn't have a non-functional libc stub.
-        # We try pthread_create on general principles.
-        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_create(&th, 0, start_routine, 0);
-                        pthread_join(th, 0);
-                        pthread_attr_init(&attr);
-                        pthread_cleanup_push(routine, 0);
-                        pthread_cleanup_pop(0) /* ; */])],
-                [ax_pthread_ok=yes],
-                [])
-
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
-
-        AC_MSG_RESULT($ax_pthread_ok)
-        if test "x$ax_pthread_ok" = xyes; then
-                break;
-        fi
-
-        PTHREAD_LIBS=""
-        PTHREAD_CFLAGS=""
-done
-fi
-
-# Various other checks:
-if test "x$ax_pthread_ok" = xyes; then
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-
-        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
-        AC_MSG_CHECKING([for joinable pthread attribute])
-        attr_name=unknown
-        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
-            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
-                           [int attr = $attr; return attr /* ; */])],
-                [attr_name=$attr; break],
-                [])
-        done
-        AC_MSG_RESULT($attr_name)
-        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
-            AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
-                               [Define to necessary symbol if this constant
-                                uses a non-standard name on your system.])
-        fi
-
-        AC_MSG_CHECKING([if more special flags are required for pthreads])
-        flag=no
-        case ${host_os} in
-            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
-            osf* | hpux*) flag="-D_REENTRANT";;
-            solaris*)
-            if test "$GCC" = "yes"; then
-                flag="-D_REENTRANT"
-            else
-                flag="-mt -D_REENTRANT"
-            fi
-            ;;
-        esac
-        AC_MSG_RESULT(${flag})
-        if test "x$flag" != xno; then
-            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
-        fi
-
-        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
-            ax_cv_PTHREAD_PRIO_INHERIT, [
-                AC_LINK_IFELSE([
-                    AC_LANG_PROGRAM([[#include <pthread.h>]], [[int i = PTHREAD_PRIO_INHERIT;]])],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
-            ])
-        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
-            AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], 1, [Have PTHREAD_PRIO_INHERIT.]))
-
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
-
-        # More AIX lossage: must compile with xlc_r or cc_r
-        if test x"$GCC" != xyes; then
-          AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
-        else
-          PTHREAD_CC=$CC
-        fi
-else
-        PTHREAD_CC="$CC"
-fi
-
-AC_SUBST(PTHREAD_LIBS)
-AC_SUBST(PTHREAD_CFLAGS)
-AC_SUBST(PTHREAD_CC)
-
-# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
-if test x"$ax_pthread_ok" = xyes; then
-        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
-        :
-else
-        ax_pthread_ok=no
-        $2
-fi
-AC_LANG_POP
-])dnl AX_PTHREAD
-- 
2.13.0



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