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diff --git a/lldb/www/python-reference.html b/lldb/www/python-reference.html index bde728f9a4c..cbf8921bc85 100755 --- a/lldb/www/python-reference.html +++ b/lldb/www/python-reference.html @@ -928,64 +928,11 @@ if target: <font color=green># We do have a symbol, print some info for the symbol</font> print symbol </tt></pre></code> - </div> - <div class="postfooter"></div> - </div> - - <div class="post"> - <h1 class ="postheader">Writing LLDB frame recognizers in Python</h1> - <div class="postcontent"> - - <p>Frame recognizers allow for retrieving information about special frames based on - ABI, arguments or other special properties of that frame, even without source - code or debug info. Currently, one use case is to extract function arguments - that would otherwise be unaccesible, or augment existing arguments.</p> - - <p>Adding a custom frame recognizer is done by implementing a Python class - and using the '<b>frame recognizer add</b>' command. The Python class should have a - '<b>get_recognized_arguments</b>' method and it will receive an argument of type - <b>lldb.SBFrame</b> representing the current frame that we are trying to recognize. - The method should return a (possibly empty) list of <b>lldb.SBValue</b> objects that - represent the recognized arguments.</p> - - <p>An example of a recognizer that retrieves the file descriptor values from libc - functions '<b>read</b>', '<b>write</b>' and '<b>close</b>' follows:</p> - -<code><pre><tt> class LibcFdRecognizer(object): - def get_recognized_arguments(self, frame): - if frame.name in ["read", "write", "close"]: - fd = frame.EvaluateExpression("$arg1").unsigned - value = lldb.target.CreateValueFromExpression("fd", "(int)%d" % fd) - return [value] - return [] -</tt></pre></code> - - <p>The file containing this implementation can be imported via '<b>command script - import</b>' and then we can register this recognizer with '<b>frame recognizer add</b>'. - It's important to restrict the recognizer to the libc library (which is - libsystem_kernel.dylib on macOS) to avoid matching functions with the same name in other modules:</p> - -<code><pre><tt>(lldb) <b>command script import .../fd_recognizer.py</b> -(lldb) <b>frame recognizer add -l fd_recognizer.LibcFdRecognizer -n read -s libsystem_kernel.dylib</b> -</tt></pre></code> + </div> + <div class="postfooter"></div> - <p>When the program is stopped at the beginning of the '<b>read</b>' function in libc, we - can view the recognizer arguments in '<b>frame variable</b>':</p> - -<code><pre><tt>(lldb) <b>b read</b> -(lldb) <b>r</b> -Process 1234 stopped -* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.3 - frame #0: 0x00007fff06013ca0 libsystem_kernel.dylib`read -(lldb) <b>frame variable</b> -(int) fd = 3 -</tt></pre></code> - - </div> - <div class="postfooter"></div> - </div> - - </div> + </div> + </div> </div> </body> </html> |
