From 9ce3833d5aebf0f0a663ffb2126da7440d0b50f7 Mon Sep 17 00:00:00 2001
From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Tue, 15 Feb 2011 01:37:44 -0800
Subject: [PATCH] Add some useful gccisms.

This are all named after the linux/compiler.h ones, not to get
uneccessarily creative.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
---
 drivers/tapdisk-interface.c |  2 +-
 drivers/tapdisk-interface.h |  2 +-
 drivers/tapdisk-log.c       |  3 +--
 drivers/tapdisk-log.h       | 10 ++++------
 drivers/tapdisk-stats.c     |  2 +-
 drivers/tapdisk.h           |  1 +
 include/compiler.h          | 35 +++++++++++++++++++++++++++++++++++
 7 files changed, 44 insertions(+), 11 deletions(-)
 create mode 100644 include/compiler.h

diff --git a/drivers/tapdisk-interface.c b/drivers/tapdisk-interface.c
index af3c315..49471c4 100644
--- a/drivers/tapdisk-interface.c
+++ b/drivers/tapdisk-interface.c
@@ -261,7 +261,7 @@ td_debug(td_image_t *image)
 	tapdisk_driver_debug(driver);
 }
 
-void
+__noreturn void
 td_panic(void)
 {
 	tlog_precious();
diff --git a/drivers/tapdisk-interface.h b/drivers/tapdisk-interface.h
index 4ee5424..d696681 100644
--- a/drivers/tapdisk-interface.h
+++ b/drivers/tapdisk-interface.h
@@ -50,6 +50,6 @@ void td_prep_read(struct tiocb *, int, char *, size_t,
 		  long long, td_queue_callback_t, void *);
 void td_prep_write(struct tiocb *, int, char *, size_t,
 		   long long, td_queue_callback_t, void *);
-void td_panic(void) __attribute__((noreturn));
+void td_panic(void) __noreturn;
 
 #endif
diff --git a/drivers/tapdisk-log.c b/drivers/tapdisk-log.c
index bf7cdd6..e531c3f 100644
--- a/drivers/tapdisk-log.c
+++ b/drivers/tapdisk-log.c
@@ -65,8 +65,7 @@ tlog_logfile_vprint(const char *fmt, va_list ap)
 	tapdisk_logfile_vprintf(&tapdisk_log.logfile, fmt, ap);
 }
 
-static void
-__attribute__((format(printf, 1, 2)))
+static void __printf(1, 2)
 tlog_logfile_print(const char *fmt, ...)
 {
 	va_list ap;
diff --git a/drivers/tapdisk-log.h b/drivers/tapdisk-log.h
index 678d78b..eeac304 100644
--- a/drivers/tapdisk-log.h
+++ b/drivers/tapdisk-log.h
@@ -36,12 +36,13 @@
 #define TLOG_DIR "/var/log/blktap"
 
 #include <stdarg.h>
+#include "compiler.h"
 
 int  tlog_open(const char *, int, int);
 void tlog_close(void);
 void tlog_precious(void);
 void tlog_vsyslog(int, const char *, va_list);
-void tlog_syslog(int, const char *, ...);
+void tlog_syslog(int, const char *, ...) __printf(2, 3);
 
 #include <syslog.h>
 
@@ -49,11 +50,8 @@ void tlog_syslog(int, const char *, ...);
 #define DPRINTF(_f, _a...) syslog(LOG_INFO, _f, ##_a)
 #define PERROR(_f, _a...)  EPRINTF(_f ": %s", ##_a, strerror(errno))
 
-void __tlog_write(int, const char *, ...)
-	__attribute__((format(printf, 2, 3)));
-
-void __tlog_error(const char *fmt, ...)
-	__attribute__((format(printf, 1, 2)));
+void __tlog_write(int, const char *, ...) __printf(2, 3);
+void __tlog_error(const char *fmt, ...) __printf(1, 2);
 
 #define tlog_write(_level, _f, _a...)			\
 	__tlog_write(_level, "%s: " _f,  __func__, ##_a)
diff --git a/drivers/tapdisk-stats.c b/drivers/tapdisk-stats.c
index c073fa2..42f420d 100644
--- a/drivers/tapdisk-stats.c
+++ b/drivers/tapdisk-stats.c
@@ -43,7 +43,7 @@ __stats_vsprintf(td_stats_t *st,
 	st->pos += vsnprintf(st->pos, size, fmt, ap);
 }
 
-static void __attribute__((format (printf, 2, 3)))
+static void __printf(2, 3)
 __stats_sprintf(td_stats_t *st,
 		     const char *fmt, ...)
 {
diff --git a/drivers/tapdisk.h b/drivers/tapdisk.h
index d552b28..eb454b4 100644
--- a/drivers/tapdisk.h
+++ b/drivers/tapdisk.h
@@ -60,6 +60,7 @@
 #include <stdint.h>
 
 #include "list.h"
+#include "compiler.h"
 #include "tapdisk-log.h"
 #include "tapdisk-utils.h"
 #include "tapdisk-stats.h"
diff --git a/include/compiler.h b/include/compiler.h
new file mode 100644
index 0000000..2c39fbb
--- /dev/null
+++ b/include/compiler.h
@@ -0,0 +1,35 @@
+#ifndef _BLKTAP_COMPILER_H
+#define _BLKTAP_COMPILER_H
+
+#ifdef __GNUC__
+#define likely(_cond)           __builtin_expect(!!(_cond), 1)
+#define unlikely(_cond)         __builtin_expect(!!(_cond), 0)
+#endif
+
+#ifndef likely
+#define likely(_cond)           (_cond)
+#endif
+
+#ifndef unlikely
+#define unlikely(_cond)         (_cond)
+#endif
+
+#ifdef __GNUC__
+#define __printf(_f, _a)        __attribute__((format (printf, _f, _a)))
+#define __scanf(_f, _a)         __attribute__((format (scanf, _f, _a)))
+#define __noreturn              __attribute__((noreturn))
+#endif
+
+#ifndef __printf
+#define __printf(_f, _a)
+#endif
+
+#ifndef __scanf
+#define __scanf(_f, _a)
+#endif
+
+#ifndef __noreturn
+#define __noreturn
+#endif
+
+#endif /* _BLKTAP_COMPILER_H */
-- 
2.39.5