On Fri, 10 Dec 2021 at 00:39, Martin Sebor via Libstdc++
<libstd...@gcc.gnu.org> wrote:
>
> On 12/9/21 4:24 PM, Jonathan Wakely via Gcc-patches wrote:
> > These warnings are triggered by perfectly valid code using std::string.
> > They're particularly bad when --enable-fully-dynamic-string is used,
> > because even std::string().begin() will give a warning.
> >
> > Use pragmas to stop the troublesome warnings for copies done by
> > std::char_traits.
>
> I'm still experimenting with some of the approaches we discussed
> last week, but based on my findings so far this was going to be
> my suggestion at lest for now, until or unless the problem turns
> out to affect more code than just std::string.
>
> That said, I noticed a typo in the patch:
>
> >
> > libstdc++-v3/ChangeLog:
> >
> > PR libstdc++/103332
> > PR libstdc++/102958
> > PR libstdc++/103483
> > * include/bits/char_traits.h: Suppress stringop and array-bounds
> > warnings.
> > ---
> > libstdc++-v3/include/bits/char_traits.h | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/libstdc++-v3/include/bits/char_traits.h
> > b/libstdc++-v3/include/bits/char_traits.h
> > index da3e0ffffaa..3f7befcf8b2 100644
> > --- a/libstdc++-v3/include/bits/char_traits.h
> > +++ b/libstdc++-v3/include/bits/char_traits.h
> > @@ -54,6 +54,11 @@ namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
> > {
> > _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > +#pragma GCC diagnostic push
> > +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> > +#pragma GCC diagnostic ignored "-Wstringop-overread"
> > +#pragma GCC diagnostic ignored "-Warray-bounds"
>
> (Just for reference, as I mentioned in my private mail, at -O1
> the same code also triggers -Wfree-nonheap-object.)
>
> > +
> > /**
> > * @brief Mapping from character type to associated types.
> > *
> > @@ -990,6 +995,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > } // namespace __detail
> > #endif // C++20
> >
> > +#pragma GCC diagnostic push
>
> This should be pop.
Oops! thanks, fixed at r12-5888 by the attached patch. Tested
x86_64-linux, pushed to trunk.
commit db184a3453b6fe810e2d9765ef8ed9028f96e968
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Fri Dec 10 09:06:37 2021
libstdc++: Fix diagnostic pragma push that should be pop
libstdc++-v3/ChangeLog:
* include/bits/char_traits.h: Change pragma push to pop.
diff --git a/libstdc++-v3/include/bits/char_traits.h
b/libstdc++-v3/include/bits/char_traits.h
index 3f7befcf8b2..13239580622 100644
--- a/libstdc++-v3/include/bits/char_traits.h
+++ b/libstdc++-v3/include/bits/char_traits.h
@@ -995,7 +995,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
} // namespace __detail
#endif // C++20
-#pragma GCC diagnostic push
+#pragma GCC diagnostic pop
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
