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

Pedro Alves
2017-06-22T10:52:29Z

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);
--
2.5.5