mingw/info/gdb/Debug-Session.html

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  12 Node:<a name="Debug%20Session">Debug Session</a>,
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  17
  18 <h4 class="subsection">Putting it all together</h4>
  19
  20    <p>In summary, when your program is ready to debug, you must follow these
  21 steps.
  22
  23      <ol type=1 start=1>
  24 <li>Make sure you have defined the supporting low-level routines
  25 (see <a href="Bootstrapping.html#Bootstrapping">What you must do for the stub</a>):
  26      <pre class="display">          <code>getDebugChar</code>, <code>putDebugChar</code>,
  27           <code>flush_i_cache</code>, <code>memset</code>, <code>exceptionHandler</code>.
  28           </pre>
  29
  30      <li>Insert these lines near the top of your program:
  31
  32      <pre class="example">          set_debug_traps();
  33           breakpoint();
  34           </pre>
  35
  36      <li>For the 680x0 stub only, you need to provide a variable called
  37 <code>exceptionHook</code>.  Normally you just use:
  38
  39      <pre class="example">          void (*exceptionHook)() = 0;
  40           </pre>
  41
  42      <p>but if before calling <code>set_debug_traps</code>, you set it to point to a
  43 function in your program, that function is called when
  44 <code>GDB</code> continues after stopping on a trap (for example, bus
  45 error).  The function indicated by <code>exceptionHook</code> is called with
  46 one parameter: an <code>int</code> which is the exception number.
  47
  48      </p><li>Compile and link together: your program, the GDB debugging stub for
  49 your target architecture, and the supporting subroutines.
  50
  51      <li>Make sure you have a serial connection between your target machine and
  52 the GDB host, and identify the serial port on the host.
  53
  54      <li>Download your program to your target machine (or get it there by
  55 whatever means the manufacturer provides), and start it.
  56
  57      <li>To start remote debugging, run GDB on the host machine, and specify
  58 as an executable file the program that is running in the remote machine.
  59 This tells GDB how to find your program's symbols and the contents
  60 of its pure text.
  61
  62      <li>Establish communication using the <code>target remote</code> command.
  63 Its argument specifies how to communicate with the target
  64 machine--either via a devicename attached to a direct serial line, or a
  65 TCP port (usually to a terminal server which in turn has a serial line
  66 to the target).  For example, to use a serial line connected to the
  67 device named <code>/dev/ttyb</code>:
  68
  69      <pre class="example">          target remote /dev/ttyb
  70           </pre>
  71
  72      <p>To use a TCP connection, use an argument of the form
  73 <code></code><var>host</var><code>:port</code>.  For example, to connect to port 2828 on a
  74 terminal server named <code>manyfarms</code>:
  75
  76      <pre class="example">          target remote manyfarms:2828
  77           </pre>
  78
  79      <p>If your remote target is actually running on the same machine as
  80 your debugger session (e.g. a simulator of your target running on
  81 the same host), you can omit the hostname.  For example, to connect
  82 to port 1234 on your local machine:
  83
  84      <pre class="example">          target remote :1234
  85           </pre>
  86
  87      <p>Note that the colon is still required here.
  88         </ol>
  89
  90    <p>Now you can use all the usual commands to examine and change data and to
  91 step and continue the remote program.
  92
  93    <p>To resume the remote program and stop debugging it, use the <code>detach</code>
  94 command.
  95
  96    <p>Whenever GDB is waiting for the remote program, if you type the
  97 interrupt character (often &lt;C-C&gt;), GDB attempts to stop the
  98 program.  This may or may not succeed, depending in part on the hardware
  99 and the serial drivers the remote system uses.  If you type the
 100 interrupt character once again, GDB displays this prompt:
 101
 102 <pre class="example">     Interrupted while waiting for the program.
 103      Give up (and stop debugging it)?  (y or n)
 104      </pre>
 105
 106    <p>If you type <kbd>y</kbd>, GDB abandons the remote debugging session.
 107 (If you decide you want to try again later, you can use <code>target
 108 remote</code> again to connect once more.)  If you type <kbd>n</kbd>, GDB
 109 goes back to waiting.
 110
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