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 `_ + 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 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: include/locale =================================================================== --- include/locale +++ include/locale @@ -623,16 +623,19 @@ ~num_get() {} template + _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 + _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 + _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/string =================================================================== --- include/string +++ include/string @@ -792,6 +792,7 @@ basic_string(const basic_string& __str, size_type __pos, const _Allocator& __a = _Allocator()); template + _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); @@ -927,7 +928,8 @@ basic_string& append(__self_view __sv) { return append(__sv.data(), __sv.size()); } basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, basic_string& @@ -937,9 +939,11 @@ basic_string& append(const value_type* __s); basic_string& append(size_type __n, value_type __c); template - inline basic_string& __append_forward_unsafe(_ForwardIterator, _ForwardIterator); + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + basic_string& __append_forward_unsafe(_ForwardIterator, _ForwardIterator); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_exactly_input_iterator<_InputIterator>::value || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value, @@ -952,7 +956,8 @@ return *this; } template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_forward_iterator<_ForwardIterator>::value && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value, @@ -988,7 +993,8 @@ #endif basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, basic_string& @@ -998,7 +1004,8 @@ basic_string& assign(const value_type* __s); basic_string& assign(size_type __n, value_type __c); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_exactly_input_iterator<_InputIterator>::value || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value, @@ -1006,7 +1013,8 @@ >::type assign(_InputIterator __first, _InputIterator __last); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_forward_iterator<_ForwardIterator>::value && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value, @@ -1023,7 +1031,8 @@ _LIBCPP_INLINE_VISIBILITY basic_string& insert(size_type __pos1, __self_view __sv) { return insert(__pos1, __sv.data(), __sv.size()); } template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, basic_string& @@ -1037,7 +1046,8 @@ _LIBCPP_INLINE_VISIBILITY iterator insert(const_iterator __pos, size_type __n, value_type __c); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_exactly_input_iterator<_InputIterator>::value || !__libcpp_string_gets_noexcept_iterator<_InputIterator>::value, @@ -1045,7 +1055,8 @@ >::type insert(const_iterator __pos, _InputIterator __first, _InputIterator __last); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_forward_iterator<_ForwardIterator>::value && __libcpp_string_gets_noexcept_iterator<_ForwardIterator>::value, @@ -1070,7 +1081,8 @@ basic_string& replace(size_type __pos1, size_type __n1, __self_view __sv) { return replace(__pos1, __n1, __sv.data(), __sv.size()); } basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, basic_string& @@ -1090,7 +1102,8 @@ _LIBCPP_INLINE_VISIBILITY basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c); template - inline typename enable_if + _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS + typename enable_if < __is_input_iterator<_InputIterator>::value, basic_string&