From 386be83f249f81bdb95bdccda473f8f1e9cad2c2 Mon Sep 17 00:00:00 2001
From: Emmanuele Bassi <ebassi@gnome.org>
Date: Mon, 17 Mar 2014 18:45:56 +0000
Subject: [PATCH] New visibility handling in Clutter

Instead of listing every public symbol inside an ancillary file, we can
use compiler annotations. This scheme is also used by GLib and GTK+.

The symbols file is left in tree until the Visual Studio rules are
fixed, but it's not used any more during distcheck.

I double-checked that the exposed ABI is the same before and after this
change, except for symbols that were never meant to be public in the
first place, and that escaped our attention when we generated the first
version of the symbols file.
---
 clutter/Makefile.am |  2 +-
 configure.ac        | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/clutter/Makefile.am b/clutter/Makefile.am
index fbea8920f..7a67ea57a 100644
--- a/clutter/Makefile.am
+++ b/clutter/Makefile.am
@@ -29,6 +29,7 @@ AM_CPPFLAGS = \
 	$(CLUTTER_DEPRECATED_CFLAGS)		\
 	$(CLUTTER_DEBUG_CFLAGS)			\
 	$(CLUTTER_PROFILE_CFLAGS)		\
+	$(CLUTTER_HIDDEN_VISIBILITY_CFLAGS)	\
 	$(NULL)
 
 AM_CFLAGS = $(CLUTTER_CFLAGS) $(MAINTAINER_CFLAGS)
@@ -850,7 +851,6 @@ libclutter_@CLUTTER_API_VERSION@_la_LDFLAGS = \
 	$(CLUTTER_LINK_FLAGS) \
 	$(CLUTTER_LT_LDFLAGS) \
 	-export-dynamic \
-	-export-symbols-regex "^(clutter|cally).*" \
 	-rpath $(libdir) \
 	$(win32_resources_ldflag) \
 	$(NULL)
diff --git a/configure.ac b/configure.ac
index 94322b56b..27e31c370 100644
--- a/configure.ac
+++ b/configure.ac
@@ -193,6 +193,36 @@ AC_ARG_ENABLE([Bsymbolic],
 AS_IF([test "x$enable_Bsymbolic" = "xyes"], [CLUTTER_LINK_FLAGS=-Wl[,]-Bsymbolic-functions])
 AC_SUBST(CLUTTER_LINK_FLAGS)
 
+# Check for the visibility flags
+CLUTTER_HIDDEN_VISIBILITY_CFLAGS=""
+case "$host" in
+  *-*-mingw*)
+    dnl on mingw32 we do -fvisibility=hidden and __declspec(dllexport)
+    AC_DEFINE([_CLUTTER_EXTERN], [__attribute__((visibility("default"))) __declspec(dllexport) extern],
+              [defines how to decorate public symbols while building])
+    CFLAGS="${CFLAGS} -fvisibility=hidden"
+    ;;
+  *)
+    dnl on other compilers, check if we can do -fvisibility=hidden
+    SAVED_CFLAGS="${CFLAGS}"
+    CFLAGS="-fvisibility=hidden"
+    AC_MSG_CHECKING([for -fvisibility=hidden compiler flag])
+    AC_TRY_COMPILE([], [int main (void) { return 0; }],
+                   AC_MSG_RESULT(yes)
+                   enable_fvisibility_hidden=yes,
+                   AC_MSG_RESULT(no)
+                   enable_fvisibility_hidden=no)
+    CFLAGS="${SAVED_CFLAGS}"
+
+    AS_IF([test "${enable_fvisibility_hidden}" = "yes"], [
+      AC_DEFINE([_CLUTTER_EXTERN], [__attribute__((visibility("default"))) extern],
+                [defines how to decorate public symbols while building])
+      CLUTTER_HIDDEN_VISIBILITY_CFLAGS="-fvisibility=hidden"
+    ])
+    ;;
+esac
+AC_SUBST(CLUTTER_HIDDEN_VISIBILITY_CFLAGS)
+
 AC_CACHE_SAVE
 
 dnl ========================================================================