Author: Shoaib Meenai Date: 2021-01-12T18:30:56-08:00 New Revision: 0066a09579ca90f60cb1947691e5a441f9f57a5d
URL: https://github.com/llvm/llvm-project/commit/0066a09579ca90f60cb1947691e5a441f9f57a5d DIFF: https://github.com/llvm/llvm-project/commit/0066a09579ca90f60cb1947691e5a441f9f57a5d.diff LOG: [libc++] Give extern templates default visibility on gcc Contrary to the current visibility macro documentation, it appears that gcc does handle visibility attribute on extern templates correctly, e.g. https://godbolt.org/g/EejuV7. We need this so that extern template instantiations of classes not marked _LIBCPP_TEMPLATE_VIS (e.g. __vector_base_common) are correctly exported with gcc when building with hidden visibility. Reviewed By: ldionne Differential Revision: https://reviews.llvm.org/D35388 Added: Modified: libcxx/docs/DesignDocs/VisibilityMacros.rst libcxx/include/__config Removed: ################################################################################ diff --git a/libcxx/docs/DesignDocs/VisibilityMacros.rst b/libcxx/docs/DesignDocs/VisibilityMacros.rst index d0d4f0adb220..20237b74de6a 100644 --- a/libcxx/docs/DesignDocs/VisibilityMacros.rst +++ b/libcxx/docs/DesignDocs/VisibilityMacros.rst @@ -131,12 +131,6 @@ Visibility Macros specified on the primary template and to export the member functions produced by the explicit instantiation in the dylib. - **GCC Behavior**: GCC ignores visibility attributes applied the type in - extern template declarations and applying an attribute results in a warning. - However since `_LIBCPP_TEMPLATE_VIS` is the same as - `__attribute__((visibility("default"))` the visibility is already correct. - The macro has an empty definition with GCC. - **Windows Behavior**: `extern template` and `dllexport` are fundamentally incompatible *on a class template* on Windows; the former suppresses instantiation, while the latter forces it. Specifying both on the same diff --git a/libcxx/include/__config b/libcxx/include/__config index f1606c6d3b1c..a6ed66857d75 100644 --- a/libcxx/include/__config +++ b/libcxx/include/__config @@ -718,7 +718,7 @@ typedef __char32_t char32_t; #endif #ifndef _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS -# if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__) +# if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) # define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__visibility__("default"))) # else # define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
