trace: initial import of a stack backtrace function for native

Sometimes the debugger just isn't fast enough to debug that pesky race
conditions. This module provides at least a little help.

cpu/native/Makefile

@@ -22,6 +22,9 @@ endif
 ifneq (,$(filter can_linux,$(USEMODULE)))
   DIRS += can
 endif
+ifneq (,$(filter trace,$(USEMODULE)))
+	DIRS += trace
+endif
 
 include $(RIOTBASE)/Makefile.base
 

cpu/native/include/trace.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    trace       Stack traceback (only under native)
+ * @ingroup     core_util
+ * @brief       Address-trace back.
+ *
+ * If you call the @ref trace_print() function a stack traceback of all return
+ * addresses up to @ref TRACE_SIZE will be printed from the point of execution.
+ *
+ * @{
+ *
+ * @file
+ * @brief
+ *
+ * @author  Martine Lenders <m.lenders@fu-berlin.de>
+ */
+#ifndef TRACE_H
+#define TRACE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Maximum number of return addresses to print
+ */
+#ifndef TRACE_SIZE
+#define TRACE_SIZE  (4U)
+#endif
+
+/**
+ * @brief   Print the last @ref TRACE_SIZE return addresses from call of this
+ *          function
+ */
+void trace_print(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* TRACE_H */
+/** @} */

cpu/native/trace/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

cpu/native/trace/trace.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2017 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @author  Martine Lenders <m.lenders@fu-berlin.de>
+ */
+
+#include <execinfo.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#include "trace.h"
+
+void trace_print(void)
+{
+    void *array[TRACE_SIZE + 1];
+    size_t size;
+
+    size = backtrace(array, TRACE_SIZE + 1);
+
+    /* skip above line's return address and start with 1 */
+    for (size_t i = 1; i < size; i++) {
+        printf("%p\n", array[i]);
+    }
+}
+
+/** @} */