[dpdk-dev] [PATCH v4 1/7] eal: introduce portable format attribute

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

When using __attribute__((format(...)) on functions, GCC on Windows
assumes MS-specific format string by default, even if the underlying
stdio implementation is ANSI-compliant (either MS Unicersal CRT
or MinGW implementation). Wrap attribute into a macro that forces
GNU-specific format string when using GCC.

Use this new attribute for logging and panic messages in EAL
and for output strings in cmdline library.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
 lib/librte_cmdline/cmdline.h                |  4 +++-
 lib/librte_eal/common/include/rte_common.h  | 17 ++++++++++++++++-
 lib/librte_eal/common/include/rte_debug.h   |  2 +-
 lib/librte_eal/common/include/rte_devargs.h |  2 +-
 lib/librte_eal/common/include/rte_log.h     |  4 ++--
 5 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/lib/librte_cmdline/cmdline.h b/lib/librte_cmdline/cmdline.h
index 27d2effdf..243f99d20 100644
--- a/lib/librte_cmdline/cmdline.h
+++ b/lib/librte_cmdline/cmdline.h
@@ -7,6 +7,8 @@
 #ifndef _CMDLINE_H_
 #define _CMDLINE_H_
 
+#include <rte_common.h>
+
 #include <termios.h>
 #include <cmdline_rdline.h>
 #include <cmdline_parse.h>
@@ -34,7 +36,7 @@ struct cmdline *cmdline_new(cmdline_parse_ctx_t *ctx, const char *prompt, int s_
 void cmdline_set_prompt(struct cmdline *cl, const char *prompt);
 void cmdline_free(struct cmdline *cl);
 void cmdline_printf(const struct cmdline *cl, const char *fmt, ...)
-	__attribute__((format(printf,2,3)));
+	__rte_format_printf(2, 3);
 int cmdline_in(struct cmdline *cl, const char *buf, int size);
 int cmdline_write_char(struct rdline *rdl, char c);
 
diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 4b5f3a31f..226c1a011 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -89,6 +89,21 @@ typedef uint16_t unaligned_uint16_t;
  */
 #define RTE_SET_USED(x) (void)(x)
 
+/**
+ * Check format string and its arguments at compile-time.
+ *
+ * GCC on Windows assumes MS-specific format string by default,
+ * even if the underlying stdio implementation is ANSI-compliant,
+ * so this must be overridden.
+ */
+#if defined(RTE_TOOLCHAIN_GCC)
+#define __rte_format_printf(format_index, first_arg) \
+	__attribute__((format(gnu_printf, format_index, first_arg)))
+#else
+#define __rte_format_printf(format_index, first_arg) \
+	__attribute__((format(printf, format_index, first_arg)))
+#endif
+
 #define RTE_PRIORITY_LOG 101
 #define RTE_PRIORITY_BUS 110
 #define RTE_PRIORITY_CLASS 120
@@ -784,7 +799,7 @@ rte_str_to_size(const char *str)
 void
 rte_exit(int exit_code, const char *format, ...)
 	__attribute__((noreturn))
-	__attribute__((format(printf, 2, 3)));
+	__rte_format_printf(2, 3);
 
 #ifdef __cplusplus
 }
diff --git a/lib/librte_eal/common/include/rte_debug.h b/lib/librte_eal/common/include/rte_debug.h
index 748d32c80..7edd4b89c 100644
--- a/lib/librte_eal/common/include/rte_debug.h
+++ b/lib/librte_eal/common/include/rte_debug.h
@@ -73,7 +73,7 @@ void __rte_panic(const char *funcname , const char *format, ...)
 #endif
 #endif
 	__attribute__((noreturn))
-	__attribute__((format(printf, 2, 3)));
+	__rte_format_printf(2, 3);
 
 #ifdef __cplusplus
 }
diff --git a/lib/librte_eal/common/include/rte_devargs.h b/lib/librte_eal/common/include/rte_devargs.h
index 882dfa0ab..898efa0d6 100644
--- a/lib/librte_eal/common/include/rte_devargs.h
+++ b/lib/librte_eal/common/include/rte_devargs.h
@@ -137,7 +137,7 @@ rte_devargs_parse(struct rte_devargs *da, const char *dev);
 int
 rte_devargs_parsef(struct rte_devargs *da,
 		   const char *format, ...)
-__attribute__((format(printf, 2, 0)));
+__rte_format_printf(2, 0);
 
 /**
  * Insert an rte_devargs in the global list.
diff --git a/lib/librte_eal/common/include/rte_log.h b/lib/librte_eal/common/include/rte_log.h
index 1bb0e6694..a0d1f4837 100644
--- a/lib/librte_eal/common/include/rte_log.h
+++ b/lib/librte_eal/common/include/rte_log.h
@@ -282,7 +282,7 @@ int rte_log(uint32_t level, uint32_t logtype, const char *format, ...)
 	__attribute__((cold))
 #endif
 #endif
-	__attribute__((format(printf, 3, 4)));
+	__rte_format_printf(3, 4);
 
 /**
  * Generates a log message.
@@ -311,7 +311,7 @@ int rte_log(uint32_t level, uint32_t logtype, const char *format, ...)
  *   - Negative on error.
  */
 int rte_vlog(uint32_t level, uint32_t logtype, const char *format, va_list ap)
-	__attribute__((format(printf,3,0)));
+	__rte_format_printf(3, 0);
 
 /**
  * Generates a log message.
-- 
2.25.1