[libc++] Fix and document visibility attributes for Clang, GCC and Windows.
Summary:
This patch fixes a number of problems with the visibility macros across GCC (on Unix) and Windows (DLL import/export semantics). All of the visibility macros are now documented under `DesignDocs/VisibilityMacros.rst`. Now I'll no longer forget the subtleties of each!
This patch adds two new visibility macros:
* `_LIBCPP_ENUM_VIS` for controlling the typeinfo of enum types. Only Clang supports this.
* `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` for redefining visibility on explicit instantiation declarations. Clang and Windows require this.
After applying this patch GCC only emits one -Wattribute warning opposed to 30+.
Reviewers: mclow.lists, EricWF
Subscribers: beanz, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D24602
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@281673 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/streambuf b/include/streambuf
index 7544aaf..3ffe413 100644
--- a/include/streambuf
+++ b/include/streambuf
@@ -574,11 +574,11 @@
return traits_type::eof();
}
-_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_streambuf<char>)
-_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_streambuf<wchar_t>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<wchar_t>)
-_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_ios<char>)
-_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_TYPE_VIS basic_ios<wchar_t>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<wchar_t>)
_LIBCPP_END_NAMESPACE_STD
