/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#ifndef COMPILER_H
#define COMPILER_H 1
-#ifdef __GNUC__
+#if __GNUC__ && !__CHECKER__
#define NO_RETURN __attribute__((__noreturn__))
#define OVS_UNUSED __attribute__((__unused__))
#define PRINTF_FORMAT(FMT, ARG1) __attribute__((__format__(printf, FMT, ARG1)))
#define MALLOC_LIKE __attribute__((__malloc__))
#define ALWAYS_INLINE __attribute__((always_inline))
#define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
+#define SENTINEL(N) __attribute__((sentinel(N)))
+#define OVS_LIKELY(CONDITION) __builtin_expect(!!(CONDITION), 1)
+#define OVS_UNLIKELY(CONDITION) __builtin_expect(!!(CONDITION), 0)
#else
#define NO_RETURN
#define OVS_UNUSED
#define MALLOC_LIKE
#define ALWAYS_INLINE
#define WARN_UNUSED_RESULT
+#define SENTINEL(N)
+#define OVS_LIKELY(CONDITION) (!!(CONDITION))
+#define OVS_UNLIKELY(CONDITION) (!!(CONDITION))
+#endif
+
+/* ISO C says that a C implementation may choose any integer type for an enum
+ * that is sufficient to hold all of its values. Common ABIs (such as the
+ * System V ABI used on i386 GNU/Linux) always use a full-sized "int", even
+ * when a smaller type would suffice.
+ *
+ * In GNU C, "enum __attribute__((packed)) name { ... }" defines 'name' as an
+ * enum compatible with a type that is no bigger than necessary. This is the
+ * intended use of OVS_PACKED_ENUM.
+ *
+ * OVS_PACKED_ENUM is intended for use only as a space optimization, since it
+ * only works with GCC. That means that it must not be used in wire protocols
+ * or otherwise exposed outside of a single process. */
+#if __GNUC__ && !__CHECKER__
+#define OVS_PACKED_ENUM __attribute__((__packed__))
+#else
+#define OVS_PACKED_ENUM
#endif
#endif /* compiler.h */