[libcxx] r307966 - [libc++] Mark string operator+ _LIBCPP_FUNC_VIS

[Shoaib Meenai via cfe-commits]

Author: smeenai
Date: Thu Jul 13 14:35:52 2017
New Revision: 307966

URL: http://llvm.org/viewvc/llvm-project?rev=307966&view=rev
Log:
[libc++] Mark string operator+ _LIBCPP_FUNC_VIS

It has an extern template instantiation declaration in the headers and a
corresponding instantiation definition in the library, so we must mark
it with _LIBCPP_FUNC_VIS to make it available outside the library.

This doesn't cause any ABI changes as-is since we don't build libc++
with hidden visibility (so the function is exported anyway). It's needed
for building libc++ with hidden visibility, however.

Clarify the Windows behavior for extern function templates while I'm
here, since this exercises that behavior.

Modified:
    libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst
    libcxx/trunk/include/string

Modified: libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst?rev=307966&r1=307965&r2=307966&view=diff
==============================================================================
--- libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst (original)
+++ libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst Thu Jul 13 14:35:52 2017
@@ -98,7 +98,8 @@ Visibility Macros
   explicit instantiations themselves are marked as exported. Note that this
   applies *only* to extern *class* templates. Extern *function* templates obey
   regular import/export semantics, and applying `dllexport` directly to the
-  extern template declaration is the correct thing to do for them.
+  extern template declaration (i.e. using `_LIBCPP_FUNC_VIS`) is the correct
+  thing to do for them.
 
 **_LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS**
   Mark the member functions, typeinfo, and vtable of an explicit instantiation

Modified: libcxx/trunk/include/string
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/string?rev=307966&r1=307965&r2=307966&view=diff
==============================================================================
--- libcxx/trunk/include/string (original)
+++ libcxx/trunk/include/string Thu Jul 13 14:35:52 2017
@@ -4006,7 +4006,7 @@ basic_string<_CharT, _Traits, _Allocator
 
 _LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_string<char>)
 _LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_string<wchar_t>)
-_LIBCPP_EXTERN_TEMPLATE(string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
 
 #if _LIBCPP_STD_VER > 11 
 // Literal suffixes for basic_string [basic.string.literals]