From 581073df44cf85411ac6cda3932fb1565f494695 Mon Sep 17 00:00:00 2001 From: Patrick Lodder Date: Mon, 12 Feb 2024 16:14:51 -0500 Subject: [PATCH] build: Update AX_PTHREAD Update build-aux/m4/ax_pthread.m4 from GNU's archive at https://www.gnu.org/software/autoconf-archive/ax_pthread.html Using commit: ac2e553eee1eb831df43f3db40b7d77f0104e823 --- build-aux/m4/ax_pthread.m4 | 267 +++++++++++++++++++++---------------- 1 file changed, 152 insertions(+), 115 deletions(-) diff --git a/build-aux/m4/ax_pthread.m4 b/build-aux/m4/ax_pthread.m4 index 4c4051ea3..9f35d1391 100644 --- a/build-aux/m4/ax_pthread.m4 +++ b/build-aux/m4/ax_pthread.m4 @@ -1,5 +1,5 @@ # =========================================================================== -# http://www.gnu.org/software/autoconf-archive/ax_pthread.html +# https://www.gnu.org/software/autoconf-archive/ax_pthread.html # =========================================================================== # # SYNOPSIS @@ -14,20 +14,24 @@ # 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.) +# Also sets PTHREAD_CC and PTHREAD_CXX to any special C compiler that is +# needed for multi-threaded programs (defaults to the value of CC +# respectively CXX otherwise). (This is necessary on e.g. AIX to use the +# special cc_r/CC_r compiler alias.) # # NOTE: You are assumed to not only compile your program with these flags, # but also to link with them as well. For example, you might link with # $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS +# $PTHREAD_CXX $CXXFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS # # If you are only building threaded programs, you may wish to use these # variables in your default LIBS, CFLAGS, and CC: # # LIBS="$PTHREAD_LIBS $LIBS" # CFLAGS="$CFLAGS $PTHREAD_CFLAGS" +# CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS" # CC="$PTHREAD_CC" +# CXX="$PTHREAD_CXX" # # In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant # has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to @@ -55,6 +59,7 @@ # # Copyright (c) 2008 Steven G. Johnson # Copyright (c) 2011 Daniel Richard G. +# Copyright (c) 2019 Marc Stevens # # This program is free software: you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by the @@ -67,7 +72,7 @@ # Public License for more details. # # You should have received a copy of the GNU General Public License along -# with this program. If not, see . +# with this program. If not, see . # # As a special exception, the respective Autoconf Macro's copyright owner # gives unlimited permission to copy, distribute and modify the configure @@ -82,7 +87,7 @@ # modified version of the Autoconf Macro, you may extend this special # exception to the GPL to apply to your modified version as well. -#serial 23 +#serial 31 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD]) AC_DEFUN([AX_PTHREAD], [ @@ -104,6 +109,7 @@ if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then ax_pthread_save_CFLAGS="$CFLAGS" ax_pthread_save_LIBS="$LIBS" AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"]) + AS_IF([test "x$PTHREAD_CXX" != "x"], [CXX="$PTHREAD_CXX"]) CFLAGS="$CFLAGS $PTHREAD_CFLAGS" LIBS="$PTHREAD_LIBS $LIBS" AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS]) @@ -123,10 +129,12 @@ fi # (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. +# Create a list of thread flags to try. Items with a "," contain both +# C compiler flags (before ",") and linker flags (after ","). Other items +# starting with a "-" are C compiler flags, and remaining 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 -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" @@ -194,14 +202,47 @@ case $host_os in # that too in a future libc.) So we'll check first for the # standard Solaris way of linking pthreads (-mt -lpthread). - ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags" + ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags" ;; esac +# Are we compiling with Clang? + +AC_CACHE_CHECK([whether $CC is Clang], + [ax_cv_PTHREAD_CLANG], + [ax_cv_PTHREAD_CLANG=no + # Note that Autoconf sets GCC=yes for Clang as well as GCC + if test "x$GCC" = "xyes"; then + AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG], + [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */ +# if defined(__clang__) && defined(__llvm__) + AX_PTHREAD_CC_IS_CLANG +# endif + ], + [ax_cv_PTHREAD_CLANG=yes]) + fi + ]) +ax_pthread_clang="$ax_cv_PTHREAD_CLANG" + + # GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC) +# Note that for GCC and Clang -pthread generally implies -lpthread, +# except when -nostdlib is passed. +# This is problematic using libtool to build C++ shared libraries with pthread: +# [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460 +# [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333 +# [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555 +# To solve this, first try -pthread together with -lpthread for GCC + AS_IF([test "x$GCC" = "xyes"], - [ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"]) + [ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"]) + +# Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first + +AS_IF([test "x$ax_pthread_clang" = "xyes"], + [ax_pthread_flags="-pthread,-lpthread -pthread"]) + # The presence of a feature test macro requesting re-entrant function # definitions is, on some systems, a strong hint that pthreads support is @@ -224,101 +265,6 @@ AS_IF([test "x$ax_pthread_check_macro" = "x--"], [ax_pthread_check_cond=0], [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"]) -# Are we compiling with Clang? - -AC_CACHE_CHECK([whether $CC is Clang], - [ax_cv_PTHREAD_CLANG], - [ax_cv_PTHREAD_CLANG=no - # Note that Autoconf sets GCC=yes for Clang as well as GCC - if test "x$GCC" = "xyes"; then - AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG], - [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */ -# if defined(__clang__) && defined(__llvm__) - AX_PTHREAD_CC_IS_CLANG -# endif - ], - [ax_cv_PTHREAD_CLANG=yes]) - fi - ]) -ax_pthread_clang="$ax_cv_PTHREAD_CLANG" - -ax_pthread_clang_warning=no - -# Clang needs special handling, because older versions handle the -pthread -# option in a rather... idiosyncratic way - -if test "x$ax_pthread_clang" = "xyes"; then - - # Clang takes -pthread; it has never supported any other flag - - # (Note 1: This will need to be revisited if a system that Clang - # supports has POSIX threads in a separate library. This tends not - # to be the way of modern systems, but it's conceivable.) - - # (Note 2: On some systems, notably Darwin, -pthread is not needed - # to get POSIX threads support; the API is always present and - # active. We could reasonably leave PTHREAD_CFLAGS empty. But - # -pthread does define _REENTRANT, and while the Darwin headers - # ignore this macro, third-party headers might not.) - - PTHREAD_CFLAGS="-pthread" - PTHREAD_LIBS= - - ax_pthread_ok=yes - - # However, older versions of Clang make a point of warning the user - # that, in an invocation where only linking and no compilation is - # taking place, the -pthread option has no effect ("argument unused - # during compilation"). They expect -pthread to be passed in only - # when source code is being compiled. - # - # Problem is, this is at odds with the way Automake and most other - # C build frameworks function, which is that the same flags used in - # compilation (CFLAGS) are also used in linking. Many systems - # supported by AX_PTHREAD require exactly this for POSIX threads - # support, and in fact it is often not straightforward to specify a - # flag that is used only in the compilation phase and not in - # linking. Such a scenario is extremely rare in practice. - # - # Even though use of the -pthread flag in linking would only print - # a warning, this can be a nuisance for well-run software projects - # that build with -Werror. So if the active version of Clang has - # this misfeature, we search for an option to squash it. - - AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread], - [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG], - [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown - # Create an alternate version of $ac_link that compiles and - # links in two steps (.c -> .o, .o -> exe) instead of one - # (.c -> exe), because the warning occurs only in the second - # step - ax_pthread_save_ac_link="$ac_link" - ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g' - ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"` - ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)" - ax_pthread_save_CFLAGS="$CFLAGS" - for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do - AS_IF([test "x$ax_pthread_try" = "xunknown"], [break]) - CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS" - ac_link="$ax_pthread_save_ac_link" - AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], - [ac_link="$ax_pthread_2step_ac_link" - AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], - [break]) - ]) - done - ac_link="$ax_pthread_save_ac_link" - CFLAGS="$ax_pthread_save_CFLAGS" - AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no]) - ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try" - ]) - - case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in - no | unknown) ;; - *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;; - esac - -fi # $ax_pthread_clang = yes if test "x$ax_pthread_ok" = "xno"; then for ax_pthread_try_flag in $ax_pthread_flags; do @@ -328,10 +274,10 @@ for ax_pthread_try_flag in $ax_pthread_flags; do AC_MSG_CHECKING([whether pthreads work without any flags]) ;; - -mt,pthread) - AC_MSG_CHECKING([whether pthreads work with -mt -lpthread]) - PTHREAD_CFLAGS="-mt" - PTHREAD_LIBS="-lpthread" + *,*) + PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"` + PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"` + AC_MSG_CHECKING([whether pthreads work with "$PTHREAD_CFLAGS" and "$PTHREAD_LIBS"]) ;; -*) @@ -371,7 +317,13 @@ for ax_pthread_try_flag in $ax_pthread_flags; do # if $ax_pthread_check_cond # error "$ax_pthread_check_macro must be defined" # endif - static void routine(void *a) { a = 0; } + static void *some_global = NULL; + static void routine(void *a) + { + /* To avoid any unused-parameter or + unused-but-set-parameter warning. */ + some_global = a; + } static void *start_routine(void *a) { return a; }], [pthread_t th; pthread_attr_t attr; pthread_create(&th, 0, start_routine, 0); @@ -393,6 +345,80 @@ for ax_pthread_try_flag in $ax_pthread_flags; do done fi + +# Clang needs special handling, because older versions handle the -pthread +# option in a rather... idiosyncratic way + +if test "x$ax_pthread_clang" = "xyes"; then + + # Clang takes -pthread; it has never supported any other flag + + # (Note 1: This will need to be revisited if a system that Clang + # supports has POSIX threads in a separate library. This tends not + # to be the way of modern systems, but it's conceivable.) + + # (Note 2: On some systems, notably Darwin, -pthread is not needed + # to get POSIX threads support; the API is always present and + # active. We could reasonably leave PTHREAD_CFLAGS empty. But + # -pthread does define _REENTRANT, and while the Darwin headers + # ignore this macro, third-party headers might not.) + + # However, older versions of Clang make a point of warning the user + # that, in an invocation where only linking and no compilation is + # taking place, the -pthread option has no effect ("argument unused + # during compilation"). They expect -pthread to be passed in only + # when source code is being compiled. + # + # Problem is, this is at odds with the way Automake and most other + # C build frameworks function, which is that the same flags used in + # compilation (CFLAGS) are also used in linking. Many systems + # supported by AX_PTHREAD require exactly this for POSIX threads + # support, and in fact it is often not straightforward to specify a + # flag that is used only in the compilation phase and not in + # linking. Such a scenario is extremely rare in practice. + # + # Even though use of the -pthread flag in linking would only print + # a warning, this can be a nuisance for well-run software projects + # that build with -Werror. So if the active version of Clang has + # this misfeature, we search for an option to squash it. + + AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread], + [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG], + [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown + # Create an alternate version of $ac_link that compiles and + # links in two steps (.c -> .o, .o -> exe) instead of one + # (.c -> exe), because the warning occurs only in the second + # step + ax_pthread_save_ac_link="$ac_link" + ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g' + ax_pthread_link_step=`AS_ECHO(["$ac_link"]) | sed "$ax_pthread_sed"` + ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)" + ax_pthread_save_CFLAGS="$CFLAGS" + for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do + AS_IF([test "x$ax_pthread_try" = "xunknown"], [break]) + CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS" + ac_link="$ax_pthread_save_ac_link" + AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], + [ac_link="$ax_pthread_2step_ac_link" + AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], + [break]) + ]) + done + ac_link="$ax_pthread_save_ac_link" + CFLAGS="$ax_pthread_save_CFLAGS" + AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no]) + ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try" + ]) + + case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in + no | unknown) ;; + *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;; + esac + +fi # $ax_pthread_clang = yes + + + # Various other checks: if test "x$ax_pthread_ok" = "xyes"; then ax_pthread_save_CFLAGS="$CFLAGS" @@ -438,7 +464,8 @@ if test "x$ax_pthread_ok" = "xyes"; then AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT], [ax_cv_PTHREAD_PRIO_INHERIT], [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include ]], - [[int i = PTHREAD_PRIO_INHERIT;]])], + [[int i = PTHREAD_PRIO_INHERIT; + return i;]])], [ax_cv_PTHREAD_PRIO_INHERIT=yes], [ax_cv_PTHREAD_PRIO_INHERIT=no]) ]) @@ -460,18 +487,28 @@ if test "x$ax_pthread_ok" = "xyes"; then [#handle absolute path differently from PATH based program lookup AS_CASE(["x$CC"], [x/*], - [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])], - [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])]) + [ + AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"]) + AS_IF([test "x${CXX}" != "x"], [AS_IF([AS_EXECUTABLE_P([${CXX}_r])],[PTHREAD_CXX="${CXX}_r"])]) + ], + [ + AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC]) + AS_IF([test "x${CXX}" != "x"], [AC_CHECK_PROGS([PTHREAD_CXX],[${CXX}_r],[$CXX])]) + ] + ) + ]) ;; esac fi fi test -n "$PTHREAD_CC" || PTHREAD_CC="$CC" +test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX" AC_SUBST([PTHREAD_LIBS]) AC_SUBST([PTHREAD_CFLAGS]) AC_SUBST([PTHREAD_CC]) +AC_SUBST([PTHREAD_CXX]) # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: if test "x$ax_pthread_ok" = "xyes"; then