[Bug bootstrap/100731] New: GCC 11 fails to build using GCC 4.8 because of missing includes

[Bug bootstrap/100731] New: GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

            Bug ID: 100731
           Summary: GCC 11 fails to build using GCC 4.8 because of missing
                    includes
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: harald at gigawatt dot nl
  Target Milestone: ---

When building GCC 11 with GCC 4.8 on a platform without _GLIBCXX_USE_C99, the
build fails. The result is:

../../gcc-11.1.0/c++tools/server.cc: In function ‘void internal_error(const
char*, ...)’:
../../gcc-11.1.0/c++tools/server.cc:199:10: error: ‘exit’ was not declared in
this scope
   exit (2);
          ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void error(const char*,
...)’:
../../gcc-11.1.0/c++tools/server.cc:233:10: error: ‘exit’ was not declared in
this scope
   exit (1);
          ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void print_usage(int)’:
../../gcc-11.1.0/c++tools/server.cc:284:15: error: ‘exit’ was not declared in
this scope
   exit (status);
               ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void print_version()’:
../../gcc-11.1.0/c++tools/server.cc:299:10: error: ‘exit’ was not declared in
this scope
   exit (0);
          ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘int
maybe_parse_socket(std::string&, module_resolver*)’:
../../gcc-11.1.0/c++tools/server.cc:828:48: error: ‘strtoul’ was not declared
in this scope
    unsigned port = strtoul (cptr + 1, &endp, 10);
                                                ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void internal_error(const
char*, ...)’:
../../gcc-11.1.0/c++tools/server.cc:200:1: warning: ‘noreturn’ function does
return [enabled by default]
 }
 ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void print_version()’:
../../gcc-11.1.0/c++tools/server.cc:300:1: warning: ‘noreturn’ function does
return [enabled by default]
 }
 ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void print_usage(int)’:
../../gcc-11.1.0/c++tools/server.cc:285:1: warning: ‘noreturn’ function does
return [enabled by default]
 }
 ^
../../gcc-11.1.0/c++tools/server.cc: In function ‘void error(const char*,
...)’:
../../gcc-11.1.0/c++tools/server.cc:234:1: warning: ‘noreturn’ function does
return [enabled by default]
 }
 ^

If the functions from <stdlib.h> are wanted, this file should just include
<stdlib.h> directly rather than relying on C++ headers pulling it in.

This happens for me on uclibc but is reproducible on glibc by locally modifying
GCC 4.8's c++config.h to not define _GLIBCXX_USE_C99.

[Bug bootstrap/100731] GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #1 from Harald van Dijk <harald at gigawatt dot nl> ---
The full configure line I used for reproducing this on glibc, btw:

  ../gcc-11.1.0/configure --prefix=$HOME/gcc-11.1.0-run CC=gcc-4.8.5
CXX=g++-4.8.5 --enable-languages=c,c++

[Bug bootstrap/100731] GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #2 from Harald van Dijk <harald at gigawatt dot nl> ---
There are more missing or wrong includes here: looking at the code, it's also
using functions from <stdio.h> without including that, but that one gets
implicitly included for me even on this old G++ so happens to not cause an
error. It's also using strrchr from <string.h> while only including <cstring>
and not qualifying as std::strrchr, which will work on all GCC versions but is
not correct.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|GCC 11 fails to build using |[11/12 Regression] GCC 11
                   |GCC 4.8 because of missing  |fails to build using GCC
                   |includes                    |4.8 because of missing
                   |                            |includes
                 CC|                            |nathan at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
   Target Milestone|---                         |11.2
           Priority|P3                          |P2

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Since you can test a build with uclibc, can you possibly come up with a
(minimal) patch to make the build work?  It sounds like amending

// OS
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

with

#include <stdlib.h>

should do the trick?  Can you possibly post such patch to
gcc-patches@gcc.gnu.org stating how you tested it?

Thanks.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #4 from Harald van Dijk <harald at gigawatt dot nl> ---
(In reply to Richard Biener from comment #3)

Yes, including <stdlib.h> is enough to get the build to pass. My last point in
comment #2, however, means that that leaves things in an inconsistent state and
that the right fix depends on what the project wants. There are basically two
options that look equally reasonable to me: adding an include of <cstdlib>
(and, although not required to fix the build, <cstdio>) and adding std::
qualifiers to everything that needs it, or adding an include of <stdlib.h> (and
<stdio.h>) and changing the other existing <c*> includes to <*.h>. Happy to
send a patch for whichever of these is preferred.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 25 May 2021, harald at gigawatt dot nl wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731
> 
> --- Comment #4 from Harald van Dijk <harald at gigawatt dot nl> ---
> (In reply to Richard Biener from comment #3)
> 
> Yes, including <stdlib.h> is enough to get the build to pass. My last point in
> comment #2, however, means that that leaves things in an inconsistent state and
> that the right fix depends on what the project wants. There are basically two
> options that look equally reasonable to me: adding an include of <cstdlib>
> (and, although not required to fix the build, <cstdio>) and adding std::
> qualifiers to everything that needs it, or adding an include of <stdlib.h> (and
> <stdio.h>) and changing the other existing <c*> includes to <*.h>. Happy to
> send a patch for whichever of these is preferred.

At this point a minimal fix is prefered - in principle the file
should be a valid source to any C++ 11 capable host compiler, not
just GCC.  The maintainer is on leave but we do want the build to
be fixed.  Now, since the file already includes csingal/cstring and 
cstdarg I'd say using the C++ wrapper to C includes and qualifying
the calls would be consistent with existing use (thus not including
stdlib.h but cstdlib).

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #6 from Harald van Dijk <harald at gigawatt dot nl> ---
(In reply to rguenther@suse.de from comment #5)
> At this point a minimal fix is prefered - in principle the file
> should be a valid source to any C++ 11 capable host compiler, not
> just GCC.  The maintainer is on leave but we do want the build to
> be fixed.  Now, since the file already includes csingal/cstring and 
> cstdarg I'd say using the C++ wrapper to C includes and qualifying
> the calls would be consistent with existing use (thus not including
> stdlib.h but cstdlib).

The minimal fix is the other one, to change the headers to <*.h>, as none of
the calls to library functions in the file are std::-qualified. :) Alright,
I'll send a patch for that once I'm able to test that the same problem is still
present on master and that the same fix is sufficient to get things working.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:7a5e9a58fbe27d8b8f04cd18bc6e1dd736e3cd12

commit r12-1041-g7a5e9a58fbe27d8b8f04cd18bc6e1dd736e3cd12
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue May 25 16:44:35 2021 +0200

    c++tools: Include <cstdlib> for exit [PR100731]

    This TU uses exit, but doesn't include <stdlib.h> or <cstdlib> and relies
    on some other header to include it indirectly, which apparently doesn't
    happen on reporter's host.

    The other <c*> headers aren't guarded either and we rely on a compiler
    capable of C++11, so maybe we can rely on <cstdlib> being around
    unconditionally.

    2021-05-25  Jakub Jelinek  <jakub@redhat.com>

            PR bootstrap/100731
            * server.cc: Include <cstdlib>.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[harald at gigawatt dot nl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #8 from Harald van Dijk <harald at gigawatt dot nl> ---
I take it that means there's no need for me to continue with what Richard asked
me to do?

At any rate, it looks like this fix won't be enough for GCC 12, but that's an
issue with the environment, not GCC 12. In !_GLIBCXX_USE_C99 environments,
there is always going to be valid C++11 code that will be rejected and it looks
like GCC 12 started using at least one std::to_string that relies on C99 in the
underlying C library. If C++11 is a bootstrap requirement, that's fair enough,
that means I need to update my environment at some point before GCC 12 will be
released.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
r230324 changed the dependency for std::to_string from _GLIBCXX_USE_C99 to
_GLIBCXX_USE_C99_STDIO, which means it's enabled for more targets (you don't
need the full C99 math library, for example!) That change is present in GCC 6.

And r272186 removed the _GLIBCXX_C99_STDIO dependency for std::to_string, so
it's always defined now. That's in GCC 10.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I plan to add the std:: qualifications, but committed the above patch because
it works likely everywhere and has been tested already.

[Bug c++/100731] [11/12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:742b4b7a644dbb4dd4a5f26c91380db826a6de07

commit r11-8491-g742b4b7a644dbb4dd4a5f26c91380db826a6de07
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue May 25 16:44:35 2021 +0200

    c++tools: Include <cstdlib> for exit [PR100731]

    This TU uses exit, but doesn't include <stdlib.h> or <cstdlib> and relies
    on some other header to include it indirectly, which apparently doesn't
    happen on reporter's host.

    The other <c*> headers aren't guarded either and we rely on a compiler
    capable of C++11, so maybe we can rely on <cstdlib> being around
    unconditionally.

    2021-05-25  Jakub Jelinek  <jakub@redhat.com>

            PR bootstrap/100731
            * server.cc: Include <cstdlib>.

    (cherry picked from commit 7a5e9a58fbe27d8b8f04cd18bc6e1dd736e3cd12)

[Bug c++/100731] [12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[11/12 Regression] GCC 11   |[12 Regression] GCC 11
                   |fails to build using GCC    |fails to build using GCC
                   |4.8 because of missing      |4.8 because of missing
                   |includes                    |includes
                 CC|                            |jason at gcc dot gnu.org

--- Comment #12 from Jason Merrill <jason at gcc dot gnu.org> ---
Let's consider this fixed for 11.

[Bug c++/100731] [12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.2                        |11.3

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11.2 is being released, retargeting bugs to GCC 11.3

[Bug c++/100731] [12 Regression] GCC 11 fails to build using GCC 4.8 because of missing includes

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100731

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.3                        |11.2
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #14 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed in GCC 11.2.0.