Add Linux Kernel style branch hinting

Ad likely/unlikely macros. Only added 2 obvious places. Need to
do profiling to determine other sites that would be helpful.

Author: stevegrubb

auparse/lru.c

@@ -26,6 +26,7 @@
 #include <string.h>
 #include <syslog.h>
 #include "lru.h"
+#include "gcc-attributes.h"
 
 //#define DEBUG
 
@@ -97,7 +98,7 @@ static unsigned int hash_name(const char *name)
 {
 	unsigned int h = 5381;
 	unsigned char c;
-	while ((c = *(const unsigned char *)name++))
+	while (likely((c = *(const unsigned char *)name++)))
 		h = ((h << 5) + h) + c;
 	return h;
 }

gcc-attributes.h

@@ -70,4 +70,13 @@
 # define __wur
 #endif
 
+/* Linux kernel style branch prediction hints. */
+#ifndef likely
+# define likely(x)   __builtin_expect(!!(x), 1)
+#endif
+
+#ifndef unlikely
+# define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
+
 #endif /* AUDIT_GCC_ATTRIBUTES_H */

src/auditd-event.c

@@ -354,7 +354,7 @@ static int format_raw(const struct audit_reply *rep)
 	        /* Replace \n with space so it looks nicer. */
 		ptr = format_buf;
 	        while (*ptr) {
-			if (*ptr == '\n')
+			if (unlikely(*ptr == '\n'))
 			        *ptr = ' ';
 			ptr++;
 		}