From 31f7b55306a92f97dbc3a88f42b4a8f8661ad689 Mon Sep 17 00:00:00 2001 From: Ting-Wei Lan Date: Wed, 3 Jan 2018 01:25:49 +0800 Subject: [PATCH] configure: Don't declare functions in AC_TRY_COMPILE and AC_LANG_PROGRAM Both AC_TRY_COMPILE and AC_LANG_PROGRAM put code passed to their second arguments to the body of the main function. This means that we cannot and should not declare functions there, or we end up checking whether the compiler support nested functions instead of whether a compiler or linker flag is supported. GCC supports nested functions and tests succeed. Clang doesn't support nested functions, so tests fail and -fvisibility=hidden won't be used. This means that functions which are not intended to be used by other programs, such as gtk_menu_tracker*, gtk_action_observ*, gtk_menu_muxer_*, become global symbols with default visibility. GNOME Shell has a private library libgnome-shell-menu.so, which also has symbols gtk_menu_tracker*, gtk_action_observ*, gtk_menu_muxer_* that are intended to be used by GNOME Shell itself. When GNOME Shell still used Autotools build system, the executable gnome-shell explicitly linked to libgnome-shell-menu.so, so the linker loaded libgnome-shell-menu.so before libgtk-3.so.0 and GNOME Shell used correct symbols from its private library. However, after GNOME Shell switched to Meson build system, gnome-shell executable no longer lists libgnome-shell-menu.so as its dependency. Even if we adds it to the build file, it won't be listed in DT_NEEDED of gnome-shell because Meson uses -Wl,--as-needed by default. This causes the runtime linker to load libgtk-3.so.0 before libgnome-shell-menu.so and symbols gtk_menu_tracker*, gtk_action_observ*, gtk_menu_muxer_* are bound to libgtk-3.so.0 instead of libgnome-shell-menu.so. GNOME Shell hangs when opening more than one window because it uses functions from the wrong library. This problem is already fixed in OpenBSD ports. The article describing it can be found on OpenBSD Journal with this link: https://undeadly.org/cgi?action=article;sid=20170930133438 https://bugzilla.gnome.org/show_bug.cgi?id=791943 --- configure.ac | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/configure.ac b/configure.ac index 904b2ba50b..16e011d5fa 100644 --- a/configure.ac +++ b/configure.ac @@ -1820,7 +1820,7 @@ case "$host" in SAVED_CFLAGS="${CFLAGS}" CFLAGS="-fvisibility=hidden" AC_MSG_CHECKING([for -fvisibility=hidden compiler flag]) - AC_TRY_COMPILE([], [int main (void) { return 0; }], + AC_TRY_COMPILE([], [return 0], AC_MSG_RESULT(yes) enable_fvisibility_hidden=yes, AC_MSG_RESULT(no) @@ -1901,8 +1901,7 @@ AC_ARG_ENABLE(Bsymbolic, [SAVED_LDFLAGS="${LDFLAGS}" AC_MSG_CHECKING([for -Bsymbolic-functions linker flag]) LDFLAGS=-Wl,-Bsymbolic-functions - AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], - [[int main (void) { return 0; }]])], + AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[return 0]])], [AC_MSG_RESULT(yes) enable_Bsymbolic=yes], [AC_MSG_RESULT(no)