1#!/usr/bin/python
2
3#----------------------------------------------------------------------
4# Be sure to add the python path that points to the LLDB shared library.
5#
6# # To use this in the embedded python interpreter using "lldb" just
7# import it with the full path using the "command script import"
8# command
9#   (lldb) command script import /path/to/cmdtemplate.py
10#----------------------------------------------------------------------
11
12import lldb
13import commands
14import optparse
15import shlex
16
17def create_framestats_options():
18    usage = "usage: %prog [options]"
19    description='''This command is meant to be an example of how to make an LLDB command that
20does something useful, follows best practices, and exploits the SB API.
21Specifically, this command computes the aggregate and average size of the variables in the current frame
22and allows you to tweak exactly which variables are to be accounted in the computation.
23'''
24    parser = optparse.OptionParser(description=description, prog='framestats',usage=usage)
25    parser.add_option('-i', '--in-scope', action='store_true', dest='inscope', help='in_scope_only = True', default=False)
26    parser.add_option('-a', '--arguments', action='store_true', dest='arguments', help='arguments = True', default=False)
27    parser.add_option('-l', '--locals', action='store_true', dest='locals', help='locals = True', default=False)
28    parser.add_option('-s', '--statics', action='store_true', dest='statics', help='statics = True', default=False)
29    return parser
30
31def the_framestats_command(debugger, command, result, dict):
32    # Use the Shell Lexer to properly parse up command options just like a
33    # shell would
34    command_args = shlex.split(command)
35    parser = create_framestats_options()
36    try:
37        (options, args) = parser.parse_args(command_args)
38    except:
39        # if you don't handle exceptions, passing an incorrect argument to the OptionParser will cause LLDB to exit
40        # (courtesy of OptParse dealing with argument errors by throwing SystemExit)
41        result.SetError ("option parsing failed")
42        return
43
44    # in a command - the lldb.* convenience variables are not to be used
45    # and their values (if any) are undefined
46    # this is the best practice to access those objects from within a command
47    target = debugger.GetSelectedTarget()
48    process = target.GetProcess()
49    thread = process.GetSelectedThread()
50    frame = thread.GetSelectedFrame()
51    if not frame.IsValid():
52        return "no frame here"
53    # from now on, replace lldb.<thing>.whatever with <thing>.whatever
54    variables_list = frame.GetVariables(options.arguments, options.locals, options.statics, options.inscope)
55    variables_count = variables_list.GetSize()
56    if variables_count == 0:
57        print >> result, "no variables here"
58        return
59    total_size = 0
60    for i in range(0,variables_count):
61        variable = variables_list.GetValueAtIndex(i)
62        variable_type = variable.GetType()
63        total_size = total_size + variable_type.GetByteSize()
64    average_size = float(total_size) / variables_count
65    print >>result, "Your frame has %d variables. Their total size is %d bytes. The average size is %f bytes" % (variables_count,total_size,average_size)
66    # not returning anything is akin to returning success
67
68def __lldb_init_module (debugger, dict):
69    # This initializer is being run from LLDB in the embedded command interpreter
70    # Make the options so we can generate the help text for the new LLDB
71    # command line command prior to registering it with LLDB below
72    parser = create_framestats_options()
73    the_framestats_command.__doc__ = parser.format_help()
74    # Add any commands contained in this module to LLDB
75    debugger.HandleCommand('command script add -f cmdtemplate.the_framestats_command framestats')
76    print 'The "framestats" command has been installed, type "help framestats" or "framestats --help" for detailed help.'
77