X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fcompiler.h;h=760389d58461d2474249598301e2e5525ed91d52;hb=ea7655d9f9d38a3af7250de8ba0b89115b5f4a5e;hp=0d7ee9f6f27c597479f1db3d4ae5371598d1fbc0;hpb=dfeb90478917b7848c89efcc6e1674f992f1ec84;p=sliver-openvswitch.git

diff --git a/lib/compiler.h b/lib/compiler.h
index 0d7ee9f6f..760389d58 100644
--- a/lib/compiler.h
+++ b/lib/compiler.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011 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.
@@ -26,6 +26,8 @@
 #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
@@ -35,6 +37,26 @@
 #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 */