libgcc/gthr-posix.h uses weak reference logic to determine if libpthread
is linked into the application or not. This is broken unless there is
special workaround with libc internal knowledge and even then static
linking needs further manual link time workaround, so this was disabled
for os/generic in libstdc++v3 and for musl in libgfortran.
The change minimizes the impact on other setups, but I think the weak
ref logic should be disabled by default, it is never entirely correct.
Conforming code can crash on a glibc setup too:
$ cat a.cpp
#include <pthread.h>
void(*f)(void) = (void(*)(void))pthread_key_create;
int main(){}
$ g++ -static a.cpp -lpthread
$ ./a.out
Segmentation fault
I reported this previously at
https://gcc.gnu.org/ml/gcc/2014-11/msg00246.html
libgfortran/Changelog:
2015-04-16 Szabolcs Nagy <szabolcs.n...@arm.com>
* acinclude.m4 (GTHREAD_USE_WEAK): Define as 0 for *-*-musl*.
* configure: Regenerate.
libstdc++v3/Changelog:
2015-04-16 Szabolcs Nagy <szabolcs.n...@arm.com>
* config/os/generic/os_defines.h (_GLIBCXX_GTHREAD_USE_WEAK): Define.
* configure.host (os_include_dir): Set to "os/generic" for linux-musl*.
diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index ba890f9..30b8b1a6 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -100,7 +100,7 @@ void foo (void);
[Define to 1 if the target supports #pragma weak])
fi
case "$host" in
- *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+ *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
AC_DEFINE(GTHREAD_USE_WEAK, 0,
[Define to 0 if the target shouldn't use #pragma weak])
;;
diff --git a/libgfortran/configure b/libgfortran/configure
index e1592f7..07542e1 100755
--- a/libgfortran/configure
+++ b/libgfortran/configure
@@ -26447,7 +26447,7 @@ $as_echo "#define SUPPORTS_WEAK 1" >>confdefs.h
fi
case "$host" in
- *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* )
+ *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
$as_echo "#define GTHREAD_USE_WEAK 0" >>confdefs.h
diff --git a/libstdc++-v3/config/os/generic/os_defines.h b/libstdc++-v3/config/os/generic/os_defines.h
index 45bf52a..103ec0e 100644
--- a/libstdc++-v3/config/os/generic/os_defines.h
+++ b/libstdc++-v3/config/os/generic/os_defines.h
@@ -33,4 +33,9 @@
// System-specific #define, typedefs, corrections, etc, go here. This
// file will come before all others.
+// Disable the weak reference logic in gthr.h for os/generic because it
+// is broken on every platform unless there is implementation specific
+// workaround in gthr-posix.h and at link-time for static linking.
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+
#endif
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index 82ddc52..a349ce3 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -271,6 +271,9 @@ case "${host_os}" in
freebsd*)
os_include_dir="os/bsd/freebsd"
;;
+ linux-musl*)
+ os_include_dir="os/generic"
+ ;;
gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
if [ "$uclibc" = "yes" ]; then
os_include_dir="os/uclibc"
