synchronize GTK2 minimum version in docs

[wxWidgets.git] / build / aclocal / visibility.m4

diff --git a/build/aclocal/visibility.m4 b/build/aclocal/visibility.m4
index 49ae7bb9e24644a6077f9632e39d7696837d2023..05f9b80dece0957dcc582245299ab444e2880c2d 100644 (file)
--- a/build/aclocal/visibility.m4
+++ b/build/aclocal/visibility.m4
@@ -43,7 +43,17 @@ AC_DEFUN([WX_VISIBILITY],
          #if defined(__GNUC__) && __GNUC__ < 4
          error this gcc is too old;
          #endif
-          
+
+         /* visibility only makes sense for ELF shared libs: */
+         #if !defined(__ELF__) && !defined(__APPLE__)
+         error this platform has no visibility;
+         #endif
+
+         /* at the time of Xcode 4.1 / Clang 3, Clang++ still didn't have the bugs sorted out: */
+         #if defined(__clang__)
+         clang compiler is still broken w.r.t. visibility;
+         #endif
+
          extern __attribute__((__visibility__("hidden"))) int hiddenvar;
          extern __attribute__((__visibility__("default"))) int exportedvar;
          extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
@@ -58,8 +68,65 @@ AC_DEFUN([WX_VISIBILITY],
       AC_LANG_POP()
       CXXFLAGS="$wx_save_CXXFLAGS"])
     AC_MSG_RESULT([$wx_cv_cc_visibility])
+    if test $wx_cv_cc_visibility = yes; then
+      dnl we do have basic visibility support, now check if we can use it:
+      dnl
+      dnl Debian/Ubuntu's gcc 4.1 is affected:
+      dnl https://bugs.launchpad.net/ubuntu/+source/gcc-4.1/+bug/109262
+      AC_MSG_CHECKING([for broken libstdc++ visibility])
+      AC_CACHE_VAL(wx_cv_cc_broken_libstdcxx_visibility, [
+        wx_save_CXXFLAGS="$CXXFLAGS"
+        wx_save_LDFLAGS="$LDFLAGS"
+        CXXFLAGS="$CXXFLAGS $CXXFLAGS_VISIBILITY"
+        LDFLAGS="$LDFLAGS -shared -fPIC"
+        AC_LANG_PUSH(C++)
+        AC_TRY_LINK(
+          [
+            #include <string>
+          ],
+          [
+            std::string s("hello");
+            return s.length();
+          ],
+          wx_cv_cc_broken_libstdcxx_visibility=no,
+          wx_cv_cc_broken_libstdcxx_visibility=yes)
+        AC_LANG_POP()
+        CXXFLAGS="$wx_save_CXXFLAGS"
+        LDFLAGS="$wx_save_LDFLAGS"])
+      AC_MSG_RESULT([$wx_cv_cc_broken_libstdcxx_visibility])
+
+      if test $wx_cv_cc_broken_libstdcxx_visibility = yes; then
+        AC_MSG_CHECKING([whether we can work around it])
+        AC_CACHE_VAL(wx_cv_cc_visibility_workaround, [
+          AC_LANG_PUSH(C++)
+          AC_TRY_LINK(
+            [
+              #pragma GCC visibility push(default)
+              #include <string>
+              #pragma GCC visibility pop
+            ],
+            [
+              std::string s("hello");
+              return s.length();
+            ],
+            wx_cv_cc_visibility_workaround=no,
+            wx_cv_cc_visibility_workaround=yes)
+          AC_LANG_POP()
+        ])
+        AC_MSG_RESULT([$wx_cv_cc_visibility_workaround])
+
+        if test $wx_cv_cc_visibility_workaround = no; then
+          dnl we can't use visibility at all then
+          wx_cv_cc_visibility=no
+        fi
+      fi
+    fi
+
     if test $wx_cv_cc_visibility = yes; then
       AC_DEFINE([HAVE_VISIBILITY])
+      if test $wx_cv_cc_broken_libstdcxx_visibility = yes; then
+        AC_DEFINE([HAVE_BROKEN_LIBSTDCXX_VISIBILITY])
+      fi
     else
       CFLAGS_VISIBILITY=""
       CXXFLAGS_VISIBILITY=""