Re: trunk -D_GLIBCXX_DEBUG #include <regex> fails

[Jonathan Wakely <jwakely@redhat.com>]

On Mon, 9 Aug 2021 at 10:51, Stephan Bergmann via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Not sure why I started to experience this now with a recent
> GCC/libstdc++ trunk build:
>
> > $ cat test.cc
> > #include <regex>
>
> > $ gcc/trunk/inst/bin/g++ -D_GLIBCXX_DEBUG -fsyntax-only test.cc
> > In file included from /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/bits/regex_automaton.h:401,
> >                  from /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/regex:60,
> >                  from test.cc:1:
> > /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/bits/regex_automaton.tcc: In member function ‘std::__detail::_StateSeq<_TraitsT> std::__detail::_StateSeq<_TraitsT>::_M_clone()’:
> > /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/bits/regex_automaton.tcc:197:12: error: ‘map’ is not a member of ‘std’
> >   197 |       std::map<_StateIdT, _StateIdT> __m;
> >       |            ^~~
> [...]
> > In file included from /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/regex:62,
> >                  from test.cc:1:
> > /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/bits/regex_compiler.h: At global scope:
> > /home/sbergman/gcc/trunk/inst/include/c++/12.0.0/bits/regex_compiler.h:541:12: error: ‘vector’ in namespace ‘std’ does not name a template type
> >   541 |       std::vector<_CharT>                       _M_char_set;
> >       |            ^~~~~~
> [...]
>
> where neither the use of std::map in bits/regex_automaton.tcc nor the
> use of std::vector in bits/regex_compiler.h are in _GLIBCXX_DEBUG-only
> code (but compiling without -D_GLIBCXX_DEBUG succeeded).

With that flag the container implementations are defined in namespace
__gnu_cxx1998, and std::map is supposed to refer to __gnu_debug::map.
But the debug map is declared in a header which isn't included by
<regex> since I replaced <map> with <bits/stl_map.h>.



>
> Anyway, what would apparently fix it for me is
>
> > diff --git a/libstdc++-v3/include/std/regex b/libstdc++-v3/include/std/regex
> > index 04fb8b2d971..29fd2956fd0 100644
> > --- a/libstdc++-v3/include/std/regex
> > +++ b/libstdc++-v3/include/std/regex
> > @@ -42,6 +42,11 @@
> >  #include <stdexcept>
> >  #include <string>
> >
> > +#if defined _GLIBCXX_DEBUG
> > +#include <map>
> > +#include <vector>
> > +#endif
> > +

I think we can do this instead:

--- a/libstdc++-v3/include/std/regex
+++ b/libstdc++-v3/include/std/regex
@@ -63,6 +63,11 @@
#include <bits/regex.h>
#include <bits/regex_executor.h>

+#ifdef _GLIBCXX_DEBUG
+# include <debug/map>
+# include <debug/vector>
+#endif
+
#if __cplusplus >= 201703L && _GLIBCXX_USE_CXX11_ABI
namespace std _GLIBCXX_VISIBILITY(default)
{


I'll test it, thanks for the report.