logging: Add optional function name prefix

Extended logger to support optional log message prepending with
function name.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

doc/subsystems/logging/logger.rst

@@ -100,6 +100,8 @@ it is not set or set lower than the override value.
 :option:`CONFIG_LOG_MAX_LEVEL`: Maximal (lowest severity) level which is
 compiled in.
 
+:option:`CONFIG_LOG_FUNCTION_NAME`: Prepend log message with function name.
+
 :option:`CONFIG_LOG_PRINTK`: Redirect printk calls to the logger.
 
 :option:`CONFIG_LOG_PRINTK_MAX_STRING_LENGTH`: Maximal string length that can

include/logging/log_core.h

@@ -42,7 +42,10 @@ extern "C" {
 
 #define LOG_DEBRACKET(...) __VA_ARGS__
 
+#define __LOG_ARG_1(val, ...) val
 #define __LOG_ARG_2(ignore_this, val, ...) val
+#define __LOG_ARGS_LESS1(val, ...) __VA_ARGS__
+
 #define __LOG_ARG_2_DEBRACKET(ignore_this, val, ...) LOG_DEBRACKET val
 
 /**
@@ -72,6 +75,26 @@ extern "C" {
 #define _LOG_EVAL2(one_or_two_args, _iftrue, _iffalse) \
 	__LOG_ARG_2_DEBRACKET(one_or_two_args _iftrue, _iffalse)
 
+/**
+ * @brief Macro for condition code generation.
+ *
+ * @param _eval Parameter evaluated against 0
+ * @param _ifzero Code included if _eval is 0. Must be wrapped in brackets.
+ * @param _ifnzero Code included if _eval is not  0.
+ *		   Must be wrapped in brackets.
+ */
+
+#define _LOG_Z_EVAL(_eval, _ifzero, _ifnzero) \
+	_LOG_Z_EVAL1(_eval, _ifzero, _ifnzero)
+
+#define _LOG_Z_EVAL1(_eval, _ifzero, _ifnzero) \
+	_LOG_Z_EVAL2(_LOG_Z_ZZZZ##_eval, _ifzero, _ifnzero)
+
+#define _LOG_Z_ZZZZ0 _LOG_Z_YYYY,
+
+#define _LOG_Z_EVAL2(one_or_two_args, _ifzero, _ifnzero) \
+	__LOG_ARG_2_DEBRACKET(one_or_two_args _ifzero, _ifnzero)
+
 /** @brief Macro for getting log level for given module.
  *
  * It is evaluated to LOG_LEVEL if defined. Otherwise CONFIG_LOG_DEFAULT_LEVEL
@@ -125,6 +148,26 @@ extern "C" {
 	  (0)								     \
 	)
 
+/**
+ * @brief Macro for optional injection of function name as first argument of
+ *	  formatted string. _LOG_Z_EVAL() macro is used to handle no arguments
+ *	  case.
+ *
+ *	  The purpose of this macro is to prefix string literal with format
+ *	  specifier for function name and inject function name as first
+ *	  argument. In order to handle string with no arguments _LOG_Z_EVAL is
+ *	  used.
+ */
+#if CONFIG_LOG_FUNCTION_NAME
+#define _LOG_STR(...) "%s: " __LOG_ARG_1(__VA_ARGS__), __func__\
+		_LOG_Z_EVAL(NUM_VA_ARGS_LESS_1(__VA_ARGS__),\
+			    (),\
+			    (, __LOG_ARGS_LESS1(__VA_ARGS__))\
+			   )
+#else
+#define _LOG_STR(...) __VA_ARGS__
+#endif
+
 /******************************************************************************/
 /****************** Internal macros for log frontend **************************/
 /******************************************************************************/
@@ -203,7 +246,7 @@ extern "C" {
 				.source_id = _id,			    \
 				.domain_id = CONFIG_LOG_DOMAIN_ID	    \
 			};						    \
-			__LOG_INTERNAL(src_level, __VA_ARGS__);		    \
+			__LOG_INTERNAL(src_level, _LOG_STR(__VA_ARGS__));   \
 		} else if (0) {						    \
 			/* Arguments checker present but never evaluated.*/ \
 			/* Placed here to ensure that __VA_ARGS__ are*/     \

subsys/logging/Kconfig

@@ -183,6 +183,12 @@ config LOG_MAX_LEVEL
 	  - 3 INFO, maximal level set to LOG_LEVEL_INFO
 	  - 4 DEBUG, maximal level set to LOG_LEVEL_DBG
 
+config LOG_FUNCTION_NAME
+	bool "Prepend log message with function name"
+	default y
+	help
+	  Prepends log message with function name.
+
 config LOG_PRINTK
 	bool "Enable processing of printk messages."
 	help

subsys/logging/log_output.c

@@ -177,7 +177,9 @@ static int ids_print(struct log_msg *msg,
 		total += print_formatted(log_output, "<%s> ", severity[level]);
 	}
 
-	total += print_formatted(log_output, "%s: ",
+	total += print_formatted(log_output,
+				IS_ENABLED(CONFIG_LOG_FUNCTION_NAME) ?
+				"%s." : "%s: ",
 				log_source_name_get(domain_id, source_id));
 
 	return total;

tests/subsys/logging/log_core/prj.conf

@@ -12,3 +12,4 @@ CONFIG_LOG_STRDUP_MAX_STRING=8
 CONFIG_KERNEL_LOG_LEVEL_OFF=y
 CONFIG_SOC_LOG_LEVEL_OFF=y
 CONFIG_ARCH_LOG_LEVEL_OFF=y
+CONFIG_LOG_FUNCTION_NAME=n