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| author | Shoaib Meenai <smeenai@fb.com> | 2021-01-12 10:29:03 -0800 |
|---|---|---|
| committer | Shoaib Meenai <smeenai@fb.com> | 2021-01-12 18:30:56 -0800 |
| commit | 0066a09579ca90f60cb1947691e5a441f9f57a5d (patch) | |
| tree | db7c2abf9ad0b34a4055e52848bbed4bf9c3e519 /libcxx | |
| parent | acea470c167fc40990d9a0f06d625a34d8a4a146 (diff) | |
| download | llvm-0066a09579ca90f60cb1947691e5a441f9f57a5d.zip llvm-0066a09579ca90f60cb1947691e5a441f9f57a5d.tar.gz llvm-0066a09579ca90f60cb1947691e5a441f9f57a5d.tar.bz2 | |
[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
Diffstat (limited to 'libcxx')
| -rw-r--r-- | libcxx/docs/DesignDocs/VisibilityMacros.rst | 6 | ||||
| -rw-r--r-- | libcxx/include/__config | 2 |
2 files changed, 1 insertions, 7 deletions
diff --git a/libcxx/docs/DesignDocs/VisibilityMacros.rst b/libcxx/docs/DesignDocs/VisibilityMacros.rst index d0d4f0a..20237b7 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 f1606c6..a6ed668 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 |