Re: [PATCH] detect incompatible aliases (PR c/81854)

[Jonathan Wakely <jwakely@redhat.com>]

On 17/08/17 21:21 -0600, Martin Sebor wrote:
>Joseph, while looking into implementing enhancement your request
>pr81824 I noticed that GCC silently accepts incompatible alias
>declarations (pr81854) so as sort of a proof-concept for the
>former I enhanced the checking already done for other kinds of
>incompatibilities to also detect those mentioned in the latter
>bug.  Attached is this patch, tested on x85_64-linux.
>
>Jonathan, the patch requires suppressing the warning in libstdc++
>compatibility symbol definitions in compatibility.cc.  I couldn't
>find a way to do it without the suppression but I'd be happy to
>try again if you have an idea for how.

Doing it that way is fine, but ...

>diff --git a/libstdc++-v3/src/c++98/compatibility.cc b/libstdc++-v3/src/c++98/compatibility.cc
>index 381f4c4..5f56b9e 100644
>--- a/libstdc++-v3/src/c++98/compatibility.cc
>+++ b/libstdc++-v3/src/c++98/compatibility.cc
>@@ -213,6 +213,11 @@ _ZNSt19istreambuf_iteratorIcSt11char_traitsIcEEppEv
> _ZNSt19istreambuf_iteratorIwSt11char_traitsIwEEppEv
>  */
> 
>+// Disable warning about declaring aliases between functions with
>+// incompatible types.
>+#pragma GCC diagnostic push
>+#pragma GCC diagnostic ignored "-Wattributes"
>+

Could this be moved closer to the point where it's needed?

It's not needed until after line 361, right?

> namespace std _GLIBCXX_VISIBILITY(default)
> {
> _GLIBCXX_BEGIN_NAMESPACE_VERSION
>@@ -509,6 +514,9 @@ _GLIBCXX_MATHL_WRAPPER1 (tan, GLIBCXX_3.4);
> #endif
> #endif // _GLIBCXX_LONG_DOUBLE_COMPAT
> 
>+// Restore disable -Wattributes
>+#pragma GCC diagnostic pop
>+
> #endif
> 
> #ifdef _GLIBCXX_LONG_DOUBLE_COMPAT
>