---
title: Lab5: RTOS modifications
toc: no
...

預期目標
-------
* 搭配`第五周</embedded/2012w4>`_課程進度

Code Coverage
--------------
- GNU code coverage tool `gcov<http://gcc.gnu.org/onlinedocs/gcc/Gcov.html>`_ is generally used to dump the coverage data when the program exits
  * for some embedded systems or for server processes you need a means to dump coverage data of particular situations, i.e. when a client connects.
- Code quality analysis for embedded systems
  * Memory management with Valgrind
  * Code coverage testing with Gcov

- `Code Quality Analysis Toolset for Embedded Systems<http://www.eclipsecon.org/2008/sub/attachments/Code_Quality_Analysis_Toolset_for_Embedded_Systems.pdf>`_
- `Using gcov and lcov<http://www.slideshare.net/maguschen/using-gcov-and-lcov>`_

Dumping gcov data at runtime
----------------------------
- `Dumping gcov data at runtime - a simple example<https://www.osadl.org/fileadmin/dam/interface/docbook/howtos/coverage.pdf>`_
- Instructions for invoking gcov

.. code-block:: prettyprint

  make
  make run
  gcov hello

- Reference output

.. code-block:: prettyprint

  File ’hello.c’
  Lines executed:100.00% of 15
  hello.c:creating ’hello.c.gcov’

- Analyze gcov output

.. code-block:: prettyprint

    tail hello.c.gcov

- Reference output

.. code-block:: prettyprint

    1:
    34: new_action.sa_flags = 0;
    -:
    35:
    1:
    36: sigaction(SIGUSR1, NULL, &old_action);
    1:
    37: if (old_action.sa_handler != SIG_IGN)
    1:
    38:
    sigaction (SIGUSR1, &new_action, NULL);
    -:
    39:
    -:
    40: /* infinite loop - to exemplify dumping coverage data while program runs */
    186275468151:
    41: for(n = 0; ; n++)
    372550936302:
    42:
    i++;
    -:
    43:}