[v2] environ-selftests: Ignore -Wself-move warning

  On 06/22/2017 10:51 AM, Pedro Alves wrote:
> On 06/22/2017 09:31 AM, Simon Marchi wrote:
>> +#if defined (__clang__)
>> +
>> +#define DIAG_PUSH_IGNORE_SELF_MOVE \
>> +  _Pragma("clang diagnostic push") \
>> +  _Pragma("clang diagnostic ignored \"-Wself-move\"")
>> +#define DIAG_POP_IGNORE_SELF_MOVE _Pragma("clang diagnostic pop")
>> +
>> +#else
>> +
>> +#define DIAG_PUSH_IGNORE_SELF_MOVE
>> +#define DIAG_POP_IGNORE_SELF_MOVE
>> +
>> +#endif
> 
> 
> Let me try writing a quick patch that puts a "STRINGIZE" macro
> in common/preprocessor.h, so we can write the above like I had
> suggested before, which is a bit more generic.  There are several
> copies in the tree of such a macro, so that'll be a good thing
> on its own anyway, IMO.
> 
> I'm not sure whether the single push-ignore macro is a good idea,
> since if we follow the pattern going forward, it requires more
> boilerplace if we need different warnings around the same code:

This is what I had in mind.  I think it should work with clang,
though I haven't tried it.


Subject: [PATCH] environ-selftests: Ignore -Wself-move warning

---
 gdb/common/diagnostics.h          | 40 +++++++++++++++++++++++++++++++++++++++
 gdb/unittests/environ-selftests.c |  8 ++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 gdb/common/diagnostics.h
  

On 2017-06-22 12:52, Pedro Alves wrote:
> On 06/22/2017 10:51 AM, Pedro Alves wrote:
>> On 06/22/2017 09:31 AM, Simon Marchi wrote:
>>> +#if defined (__clang__)
>>> +
>>> +#define DIAG_PUSH_IGNORE_SELF_MOVE \
>>> +  _Pragma("clang diagnostic push") \
>>> +  _Pragma("clang diagnostic ignored \"-Wself-move\"")
>>> +#define DIAG_POP_IGNORE_SELF_MOVE _Pragma("clang diagnostic pop")
>>> +
>>> +#else
>>> +
>>> +#define DIAG_PUSH_IGNORE_SELF_MOVE
>>> +#define DIAG_POP_IGNORE_SELF_MOVE
>>> +
>>> +#endif
>> 
>> 
>> Let me try writing a quick patch that puts a "STRINGIZE" macro
>> in common/preprocessor.h, so we can write the above like I had
>> suggested before, which is a bit more generic.  There are several
>> copies in the tree of such a macro, so that'll be a good thing
>> on its own anyway, IMO.
>> 
>> I'm not sure whether the single push-ignore macro is a good idea,
>> since if we follow the pattern going forward, it requires more
>> boilerplace if we need different warnings around the same code:
> 
> This is what I had in mind.  I think it should work with clang,
> though I haven't tried it.
> 
> 
> Subject: [PATCH] environ-selftests: Ignore -Wself-move warning
> 
> ---
>  gdb/common/diagnostics.h          | 40 
> +++++++++++++++++++++++++++++++++++++++
>  gdb/unittests/environ-selftests.c |  8 ++++++++
>  2 files changed, 48 insertions(+)
>  create mode 100644 gdb/common/diagnostics.h
> 
> diff --git a/gdb/common/diagnostics.h b/gdb/common/diagnostics.h
> new file mode 100644
> index 0000000..5a63bfd
> --- /dev/null
> +++ b/gdb/common/diagnostics.h
> @@ -0,0 +1,40 @@
> +/* Copyright (C) 2017 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or 
> modify
> +   it under the terms of the GNU General Public License as published 
> by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see 
> <http://www.gnu.org/licenses/>.  */
> +
> +#ifndef COMMON_DIAGNOSTICS_H
> +#define COMMON_DIAGNOSTICS_H
> +
> +#include "common/preprocessor.h"
> +
> +#ifdef __GNUC__
> +# define DIAGNOSTIC_PUSH _Pragma ("GCC diagnostic push")
> +# define DIAGNOSTIC_POP _Pragma ("GCC diagnostic pop")
> +# define DIAGNOSTIC_IGNORE(option) \
> +  _Pragma (STRINGIFY (GCC diagnostic ignored option))
> +#else
> +# define DIAGNOSTIC_PUSH
> +# define DIAGNOSTIC_POP
> +# define DIAGNOSTIC_IGNORE(option)
> +#endif
> +
> +#ifdef __clang__
> +# define DIAGNOSTIC_IGNORE_SELF_MOVE DIAGNOSTIC_IGNORE ("-Wself-move")
> +#else
> +# define DIAGNOSTIC_IGNORE_SELF_MOVE
> +#endif
> +
> +#endif /* COMMON_DIAGNOSTICS_H */
> diff --git a/gdb/unittests/environ-selftests.c
> b/gdb/unittests/environ-selftests.c
> index ecc3955..28b16f8 100644
> --- a/gdb/unittests/environ-selftests.c
> +++ b/gdb/unittests/environ-selftests.c
> @@ -20,6 +20,7 @@
>  #include "defs.h"
>  #include "selftest.h"
>  #include "common/environ.h"
> +#include "common/diagnostics.h"
> 
>  namespace selftests {
>  namespace gdb_environ_tests {
> @@ -136,7 +137,14 @@ run_tests ()
>    env.clear ();
>    env.set ("A", "1");
>    SELF_CHECK (strcmp (env.get ("A"), "1") == 0);
> +
> +  /* Some compilers warn about moving to self, but that's precisely
> what we want
> +     to test here, so turn this warning off.  */
> +  DIAGNOSTIC_PUSH
> +  DIAGNOSTIC_IGNORE_SELF_MOVE
>    env = std::move (env);
> +  DIAGNOSTIC_POP
> +
>    SELF_CHECK (strcmp (env.get ("A"), "1") == 0);
>    SELF_CHECK (strcmp (env.envp ()[0], "A=1") == 0);
>    SELF_CHECK (env.envp ()[1] == NULL);

I didn't understand how it would work to conditionally define the pragma 
based on the compiler, but now that I see it I understand.  LTGM.
  

On 06/22/2017 11:57 AM, Simon Marchi wrote:

> I didn't understand how it would work to conditionally define the pragma
> based on the compiler, but now that I see it I understand.  LTGM.

Great, now pushed.

Thanks,
Pedro Alves