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authorGabriel Ganne <gabriel.ganne@enea.com>2017-11-07 14:24:56 +0100
committerDamjan Marion <dmarion.lists@gmail.com>2017-11-10 20:28:45 +0000
commitbeb85cc662beda891989872b90bfd2a95e3c7a5a (patch)
treee5123053d4eb198298381e7e2b993cec56c9510b /src/vppinfra/warnings.h
parent0f85333a94e176ab915e583ff66c8774cdbda620 (diff)
add warning control macro set
Add a way to toggle on and off a warning for a specific section of code. This supports clang and gcc, and has no effect for any other compilers. This follows commit bfc29ba442dbb65599f29fe5aa44c6219ed0d3a8 and provides a generic way to handle warnings in such corner cases. To disable a warning enabled by "-Wsome-warning" for a specific code: WARN_OFF(some-warning) // disable compiler warning ; /* some code */ WARN_ON(some-warning) // enable the warning again Change-Id: I0101caa0aa775e2b905c7b3b5fef3bbdce281673 Signed-off-by: Gabriel Ganne <gabriel.ganne@enea.com>
Diffstat (limited to 'src/vppinfra/warnings.h')
-rw-r--r--src/vppinfra/warnings.h103
1 files changed, 103 insertions, 0 deletions
diff --git a/src/vppinfra/warnings.h b/src/vppinfra/warnings.h
new file mode 100644
index 00000000000..61dcc44f95a
--- /dev/null
+++ b/src/vppinfra/warnings.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+ */
+
+#ifndef __included_warnings_h__
+#define __included_warnings_h__
+
+/* Macros to check compiler version */
+#if defined(__GNUC__)
+#define COMPILER_VERSION_GTE(major, minor) \
+ (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
+#elif defined(__clang__)
+#define COMPILER_VERSION_GTE(major, minor) \
+ (__clang_major__ > (major) || \
+ (__clang_major__ == (major) && __clang_minor__ >= (minor)))
+#else /* disable all warning customization for all other compilers */
+#define COMPILER_VERSION_GTE(maj, min) 0
+#endif
+
+/* '#' needs to preceed a macro parameter */
+#define WARN_TOSTR(x) #x
+
+/*
+ * Macros to toggle off/on warnings
+ *
+ * Start by silenging pragma warnings so that we can explicitely silence
+ * a warning introduced on some compiler version and not get a warning on older
+ * versions of that same compiler.
+ *
+ * gcc corresponding warnign is "Wpargma"
+ * clang corresponding warnign is "Wunknown-warning-option"
+ *
+ * For example, Wtautological-compare is introduced in gcc-6 and this would
+ * trigger a Wpargma warning on gcc-5.
+ *
+ * Example usage to disable -Wtautological-compare warning:
+ * WARN_OFF(tautological-compare)
+ * if (...) {
+ * WARN_ON(tautological-compare)
+ * ; // conditional code
+ * }
+ */
+#if defined(__GNUC__) && COMPILER_VERSION_GTE(4, 6)
+/*
+ * GCC option to locally ignore warning was introduced in gcc-4.6
+ * gcc.gnu.org/gcc-4.6/changes.html
+ */
+#define WARN_PRAGMA(x) _Pragma (WARN_TOSTR (GCC diagnostic x))
+#define WARN_OFF(x) \
+ WARN_PRAGMA (push) WARN_PRAGMA (ignored "-Wpragmas") \
+ WARN_PRAGMA (push) WARN_PRAGMA (ignored WARN_TOSTR (-W##x))
+#define WARN_ON(x) \
+ WARN_PRAGMA (pop) \
+ WARN_PRAGMA (pop)
+
+#elif defined(__clang__) && COMPILER_VERSION_GTE(3, 3)
+/*
+ * clang option to locally ignore warning was introduced in clang-3.3
+ * releases.llvm.org/3.3/tools/clang/docs/UsersManual.html#controlling-diagnostics-via-pragmas
+ */
+#define WARN_PRAGMA(x) _Pragma (WARN_TOSTR (clang diagnostic x))
+#define WARN_OFF(x) \
+ WARN_PRAGMA (push) WARN_PRAGMA (ignored "-Wunknown-warning-option") \
+ WARN_PRAGMA (push) WARN_PRAGMA (ignored WARN_TOSTR (-W##x))
+#define WARN_ON(x) \
+ WARN_PRAGMA (pop) \
+ WARN_PRAGMA (pop)
+#else
+/* Ignore WARN_* instruction for all other compilers */
+#define WARN_OFF(x)
+#define WARN_ON(x)
+#endif
+
+/*
+ * Clang supports a wider range of warnings than gcc.
+ * Use those specific macros for the warnings that are only supported by clang
+ */
+#ifdef __clang__
+#define WARN_OFF_CLANG(x) WARN_OFF (x)
+#define WARN_ON_CLANG(x) WARN_ON (x)
+#else
+#define WARN_OFF_CLANG(x)
+#define WARN_ON_CLANG(x)
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
+#endif /* __included_warnings_h__ */