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      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 
     12 import lldb
     13 import commands
     14 import optparse
     15 import shlex
     16 
     17 def 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
     20 does something useful, follows best practices, and exploits the SB API.
     21 Specifically, this command computes the aggregate and average size of the variables in the current frame
     22 and 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 
     31 def 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 
     68 def __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