| | 1 | dnl visibility.m4 serial 1 (gettext-0.15) |
| | 2 | dnl Copyright (C) 2005 Free Software Foundation, Inc. |
| | 3 | dnl This file is free software; the Free Software Foundation |
| | 4 | dnl gives unlimited permission to copy and/or distribute it, |
| | 5 | dnl with or without modifications, as long as this notice is preserved. |
| | 6 | |
| | 7 | dnl From Bruno Haible. |
| | 8 | |
| | 9 | dnl Modified for use in wxWidgets by Vaclav Slavik: |
| | 10 | dnl - don't define HAVE_VISIBILITY (=0) if not supported |
| | 11 | dnl - use -fvisibility-inlines-hidden too |
| | 12 | dnl - test in C++ mode |
| | 13 | |
| | 14 | dnl Tests whether the compiler supports the command-line option |
| | 15 | dnl -fvisibility=hidden and the function and variable attributes |
| | 16 | dnl __attribute__((__visibility__("hidden"))) and |
| | 17 | dnl __attribute__((__visibility__("default"))). |
| | 18 | dnl Does *not* test for __visibility__("protected") - which has tricky |
| | 19 | dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on |
| | 20 | dnl MacOS X. |
| | 21 | dnl Does *not* test for __visibility__("internal") - which has processor |
| | 22 | dnl dependent semantics. |
| | 23 | dnl Does *not* test for #pragma GCC visibility push(hidden) - which is |
| | 24 | dnl "really only recommended for legacy code". |
| | 25 | dnl Set the variable CFLAG_VISIBILITY. |
| | 26 | dnl Defines and sets the variable HAVE_VISIBILITY. |
| | 27 | |
| | 28 | AC_DEFUN([WX_VISIBILITY], |
| | 29 | [ |
| | 30 | AC_REQUIRE([AC_PROG_CC]) |
| | 31 | if test -n "$GCC"; then |
| | 32 | CFLAGS_VISIBILITY="-fvisibility=hidden" |
| | 33 | CXXFLAGS_VISIBILITY="-fvisibility=hidden -fvisibility-inlines-hidden" |
| | 34 | AC_MSG_CHECKING([for symbols visibility support]) |
| | 35 | AC_CACHE_VAL(wx_cv_cc_visibility, [ |
| | 36 | wx_save_CXXFLAGS="$CXXFLAGS" |
| | 37 | CXXFLAGS="$CXXFLAGS $CXXFLAGS_VISIBILITY" |
| | 38 | AC_LANG_PUSH(C++) |
| | 39 | AC_TRY_COMPILE( |
| | 40 | [ |
| | 41 | /* we need gcc >= 4.0, older versions with visibility support |
| | 42 | didn't have class visibility: */ |
| | 43 | #if defined(__GNUC__) && __GNUC__ < 4 |
| | 44 | error this gcc is too old; |
| | 45 | #endif |
| | 46 | |
| | 47 | /* visibility only makes sense for ELF shared libs: */ |
| | 48 | #if !defined(__ELF__) && !defined(__APPLE__) |
| | 49 | error this platform has no visibility; |
| | 50 | #endif |
| | 51 | |
| | 52 | extern __attribute__((__visibility__("hidden"))) int hiddenvar; |
| | 53 | extern __attribute__((__visibility__("default"))) int exportedvar; |
| | 54 | extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void); |
| | 55 | extern __attribute__((__visibility__("default"))) int exportedfunc (void); |
| | 56 | class __attribute__((__visibility__("default"))) Foo { |
| | 57 | Foo() {} |
| | 58 | }; |
| | 59 | ], |
| | 60 | [], |
| | 61 | wx_cv_cc_visibility=yes, |
| | 62 | wx_cv_cc_visibility=no) |
| | 63 | AC_LANG_POP() |
| | 64 | CXXFLAGS="$wx_save_CXXFLAGS"]) |
| | 65 | AC_MSG_RESULT([$wx_cv_cc_visibility]) |
| | 66 | if test $wx_cv_cc_visibility = yes; then |
| | 67 | dnl we do have basic visibility support, now check if we can use it: |
| | 68 | dnl |
| | 69 | dnl Debian/Ubuntu's gcc 4.1 is affected: |
| | 70 | dnl https://bugs.launchpad.net/ubuntu/+source/gcc-4.1/+bug/109262 |
| | 71 | AC_MSG_CHECKING([for broken libstdc++ visibility]) |
| | 72 | AC_CACHE_VAL(wx_cv_cc_broken_libstdcxx_visibility, [ |
| | 73 | wx_save_CXXFLAGS="$CXXFLAGS" |
| | 74 | wx_save_LDFLAGS="$LDFLAGS" |
| | 75 | CXXFLAGS="$CXXFLAGS $CXXFLAGS_VISIBILITY" |
| | 76 | LDFLAGS="$LDFLAGS -shared -fPIC" |
| | 77 | AC_LANG_PUSH(C++) |
| | 78 | AC_TRY_LINK( |
| | 79 | [ |
| | 80 | #include <string> |
| | 81 | ], |
| | 82 | [ |
| | 83 | std::string s("hello"); |
| | 84 | return s.length(); |
| | 85 | ], |
| | 86 | wx_cv_cc_broken_libstdcxx_visibility=no, |
| | 87 | wx_cv_cc_broken_libstdcxx_visibility=yes) |
| | 88 | AC_LANG_POP() |
| | 89 | CXXFLAGS="$wx_save_CXXFLAGS" |
| | 90 | LDFLAGS="$wx_save_LDFLAGS"]) |
| | 91 | AC_MSG_RESULT([$wx_cv_cc_broken_libstdcxx_visibility]) |
| | 92 | |
| | 93 | if test $wx_cv_cc_broken_libstdcxx_visibility = yes; then |
| | 94 | AC_MSG_CHECKING([whether we can work around it]) |
| | 95 | AC_CACHE_VAL(wx_cv_cc_visibility_workaround, [ |
| | 96 | AC_LANG_PUSH(C++) |
| | 97 | AC_TRY_LINK( |
| | 98 | [ |
| | 99 | #pragma GCC visibility push(default) |
| | 100 | #include <string> |
| | 101 | #pragma GCC visibility pop |
| | 102 | ], |
| | 103 | [ |
| | 104 | std::string s("hello"); |
| | 105 | return s.length(); |
| | 106 | ], |
| | 107 | wx_cv_cc_visibility_workaround=no, |
| | 108 | wx_cv_cc_visibility_workaround=yes) |
| | 109 | AC_LANG_POP() |
| | 110 | ]) |
| | 111 | AC_MSG_RESULT([$wx_cv_cc_visibility_workaround]) |
| | 112 | |
| | 113 | if test $wx_cv_cc_visibility_workaround = no; then |
| | 114 | dnl we can't use visibility at all then |
| | 115 | wx_cv_cc_visibility=no |
| | 116 | fi |
| | 117 | fi |
| | 118 | fi |
| | 119 | |
| | 120 | if test $wx_cv_cc_visibility = yes; then |
| | 121 | AC_DEFINE([HAVE_VISIBILITY]) |
| | 122 | if test $wx_cv_cc_broken_libstdcxx_visibility = yes; then |
| | 123 | AC_DEFINE([HAVE_BROKEN_LIBSTDCXX_VISIBILITY]) |
| | 124 | fi |
| | 125 | else |
| | 126 | CFLAGS_VISIBILITY="" |
| | 127 | CXXFLAGS_VISIBILITY="" |
| | 128 | fi |
| | 129 | AC_SUBST([CFLAGS_VISIBILITY]) |
| | 130 | AC_SUBST([CXXFLAGS_VISIBILITY]) |
| | 131 | fi |
| | 132 | ]) |
projects / wxWidgets.git / blame_incremental