From 3e53b5198349c4d31f59c95aefece14ed6543933 Mon Sep 17 00:00:00 2001 From: Alexey Brodkin Date: Fri, 16 Nov 2018 14:26:18 +0300 Subject: [PATCH] package/gcc: enable __cxa_atexit This is what GCC manual says [1]: -------------------------->8---------------------- --enable-__cxa_atexit Define if you want to use __cxa_atexit, rather than atexit, to register C++ destructors for local statics and global objects. This is essential for fully standards-compliant handling of destructors, but requires __cxa_atexit in libc. This option is currently only available on systems with GNU libc ... -------------------------->8---------------------- Important disadvantages of a simple atexit() are that [2]: -------------------------->8---------------------- 1999 C Standard only requires that the implementation support 32 registered functions, although most implementations support many more. More important it does not deal at all with the ability in most implementations to remove DSOs from a running program image by calling dlclose prior to program termination. -------------------------->8---------------------- Also it seems like all libc's we support in Buildroot (Glibc, uClibc and musl) support __cxa_at_exit() so enable it unconditionally. FWIW if we look around we'll see: 1. In OpenEmbedded it is enabled for everything except gcc-cross-initial: [3], [4] 2. In Crosstool-NG it is enabled by default: [5] 3. In OpenWrt it is disabled only for uClibc, otherwise enabled: [6] So I think we should be good with it as well. [1] https://gcc.gnu.org/install/configure.html [2] https://itanium-cxx-abi.github.io/cxx-abi/abi.html#dso-dtor-motivation [3] https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-devtools/gcc/gcc-configure-common.inc#L59 [4] https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-devtools/gcc/gcc-cross-initial.inc#L23 [5] https://github.com/crosstool-ng/crosstool-ng/blob/master/config/cc/gcc.in#L270 [6] https://github.com/openwrt/openwrt/blob/master/toolchain/gcc/common.mk#L170 Signed-off-by: Alexey Brodkin Cc: Nicolas Cavallari Cc: Thomas Petazzoni Cc: Mark Corbin Cc: Romain Naour Cc: Peter Korsgaard Cc: Bernd Kuhls Cc: Claudiu Zissulescu Cc: Cupertino Miranda Cc: Vineet Gupta Reviewed-by: Arnout Vandecappelle (Essensium/Mind) Signed-off-by: Thomas Petazzoni --- package/gcc/gcc.mk | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk index e47435677e..5901624ea5 100644 --- a/package/gcc/gcc.mk +++ b/package/gcc/gcc.mk @@ -87,7 +87,7 @@ HOST_GCC_COMMON_DEPENDENCIES = \ HOST_GCC_COMMON_CONF_OPTS = \ --target=$(GNU_TARGET_NAME) \ --with-sysroot=$(STAGING_DIR) \ - --disable-__cxa_atexit \ + --enable-__cxa_atexit \ --with-gnu-ld \ --disable-libssp \ --disable-multilib \ -- 2.30.2