[gcc r11-8912] libstdc++: Define net::socket_base::message_flags operators as friends [PR 100285]

[gcc r11-8912] libstdc++: Define net::socket_base::message_flags operators as friends [PR 100285]

[Jonathan Wakely]

https://gcc.gnu.org/g:fb7ca13de4b6d267960fb2c51092343a9e731f66

commit r11-8912-gfb7ca13de4b6d267960fb2c51092343a9e731f66
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Apr 27 11:07:47 2021 +0100

    libstdc++: Define net::socket_base::message_flags operators as friends [PR 100285]
    
    The overloaded operators for socket_base::message_flags should only be
    defined when the message_flags type itself is defined. Rather than
    duplicate the preprocessor conditional, this moves the operators into
    the same scope as the type, defining them as hidden friends.
    
    As well as fixing the bug, this has all the usual advantages of hidden
    friends (they are not visible to normal name lookup for unrelated
    types).
    
    For consistency, do the same for the resolver_base::flags bitmask
    operators too.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/100285
            * include/experimental/internet (resolver_base::flags):
            Define overloaded operators as hidden friends.
            * include/experimental/socket (socket_base::message_flags):
            Likewise.
    
    (cherry picked from commit 8aadb4fedb17e7a44583a7a5a4e96b1874e1ce98)

Diff:
---
 libstdc++-v3/include/experimental/internet | 50 ++++++++++----------
 libstdc++-v3/include/experimental/socket   | 74 ++++++++++++++----------------
 2 files changed, 59 insertions(+), 65 deletions(-)

diff --git a/libstdc++-v3/include/experimental/internet b/libstdc++-v3/include/experimental/internet
index 2e3fd06ead2..11961762880 100644
--- a/libstdc++-v3/include/experimental/internet
+++ b/libstdc++-v3/include/experimental/internet
@@ -1660,38 +1660,38 @@ namespace ip
     static constexpr flags all_matching		= (flags)AI_ALL;
     static constexpr flags address_configured	= (flags)AI_ADDRCONFIG;
 
-  protected:
-    resolver_base() = default;
-    ~resolver_base() = default;
-  };
+    friend constexpr flags
+    operator&(flags __f1, flags __f2) noexcept
+    { return flags( int(__f1) & int(__f2) ); }
 
-  constexpr resolver_base::flags
-  operator&(resolver_base::flags __f1, resolver_base::flags __f2) noexcept
-  { return resolver_base::flags( int(__f1) & int(__f2) ); }
+    friend constexpr flags
+    operator|(flags __f1, flags __f2) noexcept
+    { return flags( int(__f1) | int(__f2) ); }
 
-  constexpr resolver_base::flags
-  operator|(resolver_base::flags __f1, resolver_base::flags __f2) noexcept
-  { return resolver_base::flags( int(__f1) | int(__f2) ); }
+    friend constexpr flags
+    operator^(flags __f1, flags __f2) noexcept
+    { return flags( int(__f1) ^ int(__f2) ); }
 
-  constexpr resolver_base::flags
-  operator^(resolver_base::flags __f1, resolver_base::flags __f2) noexcept
-  { return resolver_base::flags( int(__f1) ^ int(__f2) ); }
+    friend constexpr flags
+    operator~(flags __f) noexcept
+    { return flags( ~int(__f) ); }
 
-  constexpr resolver_base::flags
-  operator~(resolver_base::flags __f) noexcept
-  { return resolver_base::flags( ~int(__f) ); }
+    friend constexpr flags&
+    operator&=(flags& __f1, flags __f2) noexcept
+    { return __f1 = (__f1 & __f2); }
 
-  constexpr resolver_base::flags&
-  operator&=(resolver_base::flags& __f1, resolver_base::flags __f2) noexcept
-  { return __f1 = (__f1 & __f2); }
+    friend constexpr flags&
+    operator|=(flags& __f1, flags __f2) noexcept
+    { return __f1 = (__f1 | __f2); }
 
-  constexpr resolver_base::flags&
-  operator|=(resolver_base::flags& __f1, resolver_base::flags __f2) noexcept
-  { return __f1 = (__f1 | __f2); }
+    friend constexpr flags&
+    operator^=(flags& __f1, flags __f2) noexcept
+    { return __f1 = (__f1 ^ __f2); }
 
-  constexpr resolver_base::flags&
-  operator^=(resolver_base::flags& __f1, resolver_base::flags __f2) noexcept
-  { return __f1 = (__f1 ^ __f2); }
+  protected:
+    resolver_base() = default;
+    ~resolver_base() = default;
+  };
 
   // TODO define resolver_base::flags static constants in .so for C++14 mode
 
diff --git a/libstdc++-v3/include/experimental/socket b/libstdc++-v3/include/experimental/socket
index 18849f607f8..bf6a8c87e67 100644
--- a/libstdc++-v3/include/experimental/socket
+++ b/libstdc++-v3/include/experimental/socket
@@ -319,13 +319,38 @@ inline namespace v1
       = (message_flags)MSG_DONTROUTE;
 
     static const int max_listen_connections = SOMAXCONN;
-#endif
 
-  protected:
-    socket_base() = default;
-    ~socket_base() = default;
+    // message_flags bitmask operations are defined as hidden friends.
 
-#ifdef _GLIBCXX_HAVE_SYS_SOCKET_H
+    friend constexpr message_flags
+    operator&(message_flags __f1, message_flags __f2) noexcept
+    { return message_flags( int(__f1) & int(__f2) ); }
+
+    friend constexpr message_flags
+    operator|(message_flags __f1, message_flags __f2) noexcept
+    { return message_flags( int(__f1) | int(__f2) ); }
+
+    friend constexpr message_flags
+    operator^(message_flags __f1, message_flags __f2) noexcept
+    { return message_flags( int(__f1) ^ int(__f2) ); }
+
+    friend constexpr message_flags
+    operator~(message_flags __f) noexcept
+    { return message_flags( ~int(__f) ); }
+
+    friend constexpr message_flags&
+    operator&=(message_flags& __f1, message_flags __f2) noexcept
+    { return __f1 = (__f1 & __f2); }
+
+    friend constexpr message_flags&
+    operator|=(message_flags& __f1, message_flags __f2) noexcept
+    { return __f1 = (__f1 | __f2); }
+
+    friend constexpr message_flags&
+    operator^=(message_flags& __f1, message_flags __f2) noexcept
+    { return __f1 = (__f1 ^ __f2); }
+
+  protected:
     struct __msg_hdr : ::msghdr
     {
 #ifdef IOV_MAX
@@ -382,42 +407,11 @@ inline namespace v1
 	}
     };
 #endif
-  };
 
-  constexpr socket_base::message_flags
-  operator&(socket_base::message_flags __f1, socket_base::message_flags __f2)
-    noexcept
-  { return socket_base::message_flags( int(__f1) & int(__f2) ); }
-
-  constexpr socket_base::message_flags
-  operator|(socket_base::message_flags __f1, socket_base::message_flags __f2)
-    noexcept
-  { return socket_base::message_flags( int(__f1) | int(__f2) ); }
-
-  constexpr socket_base::message_flags
-  operator^(socket_base::message_flags __f1, socket_base::message_flags __f2)
-    noexcept
-  { return socket_base::message_flags( int(__f1) ^ int(__f2) ); }
-
-  constexpr socket_base::message_flags
-  operator~(socket_base::message_flags __f)
-    noexcept
-  { return socket_base::message_flags( ~int(__f) ); }
-
-  constexpr socket_base::message_flags&
-  operator&=(socket_base::message_flags& __f1, socket_base::message_flags __f2)
-    noexcept
-  { return __f1 = (__f1 & __f2); }
-
-  constexpr socket_base::message_flags&
-  operator|=(socket_base::message_flags& __f1, socket_base::message_flags __f2)
-    noexcept
-  { return __f1 = (__f1 | __f2); }
-
-  constexpr socket_base::message_flags&
-  operator^=(socket_base::message_flags& __f1, socket_base::message_flags __f2)
-    noexcept
-  { return __f1 = (__f1 ^ __f2); }
+  protected:
+    socket_base() = default;
+    ~socket_base() = default;
+  };
 
   // TODO define socket_base static constants in .so for C++14 mode