smeenai updated this revision to Diff 90108.
smeenai edited the summary of this revision.
smeenai added a comment.
Addressing comments
https://reviews.llvm.org/D29157
Files:
docs/DesignDocs/VisibilityMacros.rst
include/__config
include/locale
include/string
Index: include/string
===================================================================
--- include/string
+++ include/string
@@ -792,6 +792,7 @@
basic_string(const basic_string& __str, size_type __pos,
const _Allocator& __a = _Allocator());
template<class _Tp>
+ _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
basic_string(const _Tp& __t, size_type __pos, size_type __n,
const allocator_type& __a = allocator_type(),
typename enable_if<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, void>::type* = 0);
Index: include/locale
===================================================================
--- include/locale
+++ include/locale
@@ -623,16 +623,19 @@
~num_get() {}
template <class _Fp>
+ _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
iter_type __do_get_floating_point
(iter_type __b, iter_type __e, ios_base& __iob,
ios_base::iostate& __err, _Fp& __v) const;
template <class _Signed>
+ _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
iter_type __do_get_signed
(iter_type __b, iter_type __e, ios_base& __iob,
ios_base::iostate& __err, _Signed& __v) const;
template <class _Unsigned>
+ _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
iter_type __do_get_unsigned
(iter_type __b, iter_type __e, ios_base& __iob,
ios_base::iostate& __err, _Unsigned& __v) const;
Index: include/__config
===================================================================
--- include/__config
+++ include/__config
@@ -591,6 +591,7 @@
#define _LIBCPP_EXTERN_VIS _LIBCPP_DLL_VIS
#define _LIBCPP_EXCEPTION_ABI _LIBCPP_DLL_VIS
#define _LIBCPP_HIDDEN
+#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
#define _LIBCPP_TEMPLATE_VIS
#define _LIBCPP_FUNC_VIS_ONLY
#define _LIBCPP_ENUM_VIS
@@ -614,6 +615,8 @@
#endif
#endif
+#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_HIDDEN
+
#ifndef _LIBCPP_FUNC_VIS
#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#define _LIBCPP_FUNC_VIS __attribute__ ((__visibility__("default")))
@@ -668,7 +671,7 @@
#ifndef _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
# if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
-# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__type_visibility__("default")))
+# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__visibility__("default")))
# else
# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
# endif
Index: docs/DesignDocs/VisibilityMacros.rst
===================================================================
--- docs/DesignDocs/VisibilityMacros.rst
+++ docs/DesignDocs/VisibilityMacros.rst
@@ -110,6 +110,35 @@
the extern template declaration) as exported on Windows, as discussed above.
On all other platforms, this macro has an empty definition.
+**_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS**
+ Mark a symbol as hidden so it will not be exported from shared libraries. This
+ is intended specifically for method templates of either classes marked with
+ `_LIBCPP_TYPE_VIS` or classes with an extern template instantiation
+ declaration marked with `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS`.
+
+ When building libc++ with hidden visibility, we want explicit template
+ instantiations to export members, which is consistent with existing Windows
+ behavior. We also want classes annotated with `_LIBCPP_TYPE_VIS` to export
+ their members, which is again consistent with existing Windows behavior.
+ Both these changes are necessary for clients to be able to link against a
+ libc++ DSO built with hidden visibility without encountering missing symbols.
+
+ An unfortunate side effect, however, is that method templates of classes
+ either marked `_LIBCPP_TYPE_VIS` or with extern template instantiation
+ declarations marked with `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` also get default
+ visibility when instantiated. These methods are often implicitly instantiated
+ inside other libraries which use the libc++ headers, and will therefore end up
+ being exported from those libraries, since those implicit instantiations will
+ receive default visibility. This is not acceptable for libraries that wish to
+ control their visibility, and led to PR30642.
+
+ Consequently, all such problematic method templates are explicitly marked
+ either hidden (via this macro) or inline, so that they don't leak into client
+ libraries. The problematic methods were found by running
+ `bad-visibility-finder <https://github.com/smeenai/bad-visibility-finder>`_
+ against the libc++ headers after making `_LIBCPP_TYPE_VIS` and
+ `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` expand to default visibility.
+
**_LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY**
Mark a member function of a class template as visible and always inline. This
macro should only be applied to member functions of class templates that are
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
