Add MBED_NORETURN attributes

Save some ROM space by putting MBED_NORETURN attributes on error
functions and failed asserts.

mbed_error was documented as returning an error code. It never
actually could return, so documentation updated, but return type
kept.

features/lwipstack/lwip-sys/arch/cc.h

@@ -97,7 +97,7 @@
 void lwip_mbed_tracef_debug(const char *fmt, ...);
 void lwip_mbed_tracef_error(const char *fmt, ...);
 void lwip_mbed_tracef_warn(const char *fmt, ...);
-void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file, unsigned int line);
+MBED_NORETURN void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file, unsigned int line);
 
 #define LWIP_PLATFORM_DIAG(vars)         lwip_mbed_tracef_debug vars
 #define LWIP_PLATFORM_DIAG_SEVERE(vars)  lwip_mbed_tracef_error vars
@@ -109,7 +109,7 @@ void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file,
 #else // MBED_CONF_LWIP_USE_MBED_TRACE
 #include <stdio.h>
 
-void assert_printf(char *msg, int line, char *file);
+MBED_NORETURN void assert_printf(char *msg, int line, char *file);
 
 /* Plaform specific diagnostic output */
 #define LWIP_PLATFORM_DIAG(vars) printf vars

features/lwipstack/lwip-sys/arch/lwip_sys_arch.c

@@ -589,7 +589,7 @@ void lwip_mbed_tracef_error(const char *fmt, ...)
     va_end(ap);
 }
 
-void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file, unsigned int line)
+MBED_NORETURN void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file, unsigned int line)
 {
     mbed_tracef(TRACE_LEVEL_ERROR, "lwIP", "Assertion failed: %s, function %s, file %s, line %u.", msg, func, file, line);
     exit(EXIT_FAILURE); // XXX how about abort? mbed_assert uses exit, so follow suit
@@ -605,7 +605,7 @@ void lwip_mbed_assert_fail(const char *msg, const char *func, const char *file,
     \param[in]    line  Line number in file with error
     \param[in]    file  Filename with error
  */
-void assert_printf(char *msg, int line, char *file) {
+MBED_NORETURN void assert_printf(char *msg, int line, char *file) {
     if (msg)
         error("%s:%d in file %s\n", msg, line, file);
     else

platform/mbed_assert.c

@@ -20,7 +20,7 @@
 #include "platform/mbed_critical.h"
 #include "platform/mbed_error.h"
 
-void mbed_assert_internal(const char *expr, const char *file, int line)
+MBED_NORETURN void mbed_assert_internal(const char *expr, const char *file, int line)
 {
     core_util_critical_section_enter();
     mbed_error(MBED_ERROR_ASSERTION_FAILED, expr, 0, file, line);

platform/mbed_assert.h

@@ -24,6 +24,7 @@
 #define MBED_ASSERT_H
 
 #include "mbed_preprocessor.h"
+#include "mbed_toolchain.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -37,7 +38,7 @@ extern "C" {
  *  @param file File where assertation failed.
  *  @param line Failing assertation line number.
  */
-void mbed_assert_internal(const char *expr, const char *file, int line);
+MBED_NORETURN void mbed_assert_internal(const char *expr, const char *file, int line);
 
 #ifdef __cplusplus
 }

platform/mbed_board.c

@@ -21,7 +21,7 @@
 #include "platform/mbed_retarget.h"
 #include "platform/mbed_critical.h"
 
-WEAK void mbed_die(void)
+WEAK MBED_NORETURN void mbed_die(void)
 {
 #if !defined (NRF51_H) && !defined(TARGET_EFM32)
     core_util_critical_section_enter();

platform/mbed_error.c

@@ -45,7 +45,7 @@ static mbed_error_hook_t error_hook = NULL;
 static mbed_error_status_t handle_error(mbed_error_status_t error_status, unsigned int error_value, const char *filename, int line_number, void *caller);
 
 //Helper function to halt the system
-static void mbed_halt_system(void)
+static MBED_NORETURN void mbed_halt_system(void)
 {
     // Prevent recursion if halt is called again during halt attempt - try
     // something simple instead.
@@ -66,7 +66,7 @@ static void mbed_halt_system(void)
     exit(1);
 }
 
-WEAK void error(const char *format, ...)
+WEAK MBED_NORETURN void error(const char *format, ...)
 {
     // Prevent recursion if error is called again during store+print attempt
     if (!core_util_atomic_flag_test_and_set(&error_in_progress)) {
@@ -169,14 +169,14 @@ int mbed_get_error_count(void)
     return error_count;
 }
 
-//Sets a fatal error
+//Sets a non-fatal error
 mbed_error_status_t mbed_warning(mbed_error_status_t error_status, const char *error_msg, unsigned int error_value, const char *filename, int line_number)
 {
     return handle_error(error_status, error_value, filename, line_number, MBED_CALLER_ADDR());
 }
 
 //Sets a fatal error, this function is marked WEAK to be able to override this for some tests
-WEAK mbed_error_status_t mbed_error(mbed_error_status_t error_status, const char *error_msg, unsigned int error_value, const char *filename, int line_number)
+WEAK MBED_NORETURN mbed_error_status_t mbed_error(mbed_error_status_t error_status, const char *error_msg, unsigned int error_value, const char *filename, int line_number)
 {
     // Prevent recursion if error is called again during store+print attempt
     if (!core_util_atomic_flag_test_and_set(&error_in_progress)) {
@@ -188,8 +188,6 @@ WEAK mbed_error_status_t mbed_error(mbed_error_status_t error_status, const char
     }
 
     mbed_halt_system();
-
-    return MBED_ERROR_FAILED_OPERATION;
 }
 
 //Register an application defined callback with error handling

platform/mbed_error.h

@@ -169,8 +169,7 @@ typedef int mbed_error_status_t;
  * @param  error_status     mbed_error_status_t status to be set(See mbed_error_status_t enum above for available error status values).
  * @param  error_msg        The error message to be printed out to STDIO/Serial.
  * @param  error_value      Value associated with the error status. This would depend on error code/error scenario. Only available with MBED_ERROR1
- * @return                  0 or MBED_SUCCESS.
+ * @return                  Does not return
- *                          MBED_ERROR_INVALID_ARGUMENT if called with invalid error status/codes
  *
  * @code
  *
@@ -872,7 +871,7 @@ typedef struct _mbed_error_ctx {
  *
  */
 
-void error(const char *format, ...);
+MBED_NORETURN void error(const char *format, ...);
 
 /**
  * Call this Macro to generate a mbed_error_status_t value for a System error
@@ -979,8 +978,7 @@ int mbed_get_error_count(void);
  * @param  error_value      Value associated with the error status. This would depend on error code/error scenario.
  * @param  filename         Name of the source file originating the error( Most callers can pass __FILE__ here ).
  * @param  line_number      The line number of the source file originating the error( Most callers can pass __LINE__ here ) .
- * @return                  0 or MBED_SUCCESS.
+ * @return                  Does not return.
- *                          MBED_ERROR_INVALID_ARGUMENT if called with invalid error status/codes
  *
  * @code
  *
@@ -990,7 +988,7 @@ int mbed_get_error_count(void);
  *
  * @note See MBED_WARNING/MBED_ERROR macros which provides a wrapper on this API
  */
-mbed_error_status_t mbed_error(mbed_error_status_t error_status, const char *error_msg, unsigned int error_value, const char *filename, int line_number);
+MBED_NORETURN mbed_error_status_t mbed_error(mbed_error_status_t error_status, const char *error_msg, unsigned int error_value, const char *filename, int line_number);
 
 /**
  * Registers an application defined error callback with the error handling system.

platform/mbed_interface.h

@@ -121,7 +121,7 @@ void mbed_mac_address(char *mac);
 
 /** Cause the mbed to flash the BLOD (Blue LEDs Of Death) sequence
  */
-void mbed_die(void);
+MBED_NORETURN void mbed_die(void);
 
 /** Print out an error message.  This is typically called when
  * handling a crash.