#!/usr/bin/python #---------------------------------------------------------------------- # Be sure to add the python path that points to the LLDB shared library. # # # To use this in the embedded python interpreter using "lldb" just # import it with the full path using the "command script import" # command # (lldb) command script import /path/to/cmdtemplate.py #---------------------------------------------------------------------- import commands import platform import os import sys try: # Just try for LLDB in case PYTHONPATH is already correctly setup import lldb except ImportError: lldb_python_dirs = list() # lldb is not in the PYTHONPATH, try some defaults for the current platform platform_system = platform.system() if platform_system == 'Darwin': # On Darwin, try the currently selected Xcode directory xcode_dir = commands.getoutput("xcode-select --print-path") if xcode_dir: lldb_python_dirs.append(os.path.realpath(xcode_dir + '/../SharedFrameworks/LLDB.framework/Resources/Python')) lldb_python_dirs.append(xcode_dir + '/Library/PrivateFrameworks/LLDB.framework/Resources/Python') lldb_python_dirs.append('/System/Library/PrivateFrameworks/LLDB.framework/Resources/Python') success = False for lldb_python_dir in lldb_python_dirs: if os.path.exists(lldb_python_dir): if not (sys.path.__contains__(lldb_python_dir)): sys.path.append(lldb_python_dir) try: import lldb except ImportError: pass else: print 'imported lldb from: "%s"' % (lldb_python_dir) success = True break if not success: print "error: couldn't locate the 'lldb' module, please set PYTHONPATH correctly" sys.exit(1) import commands import optparse import shlex import time def create_types_options(): usage = "usage: %prog [options]" description='''This command will help you verify that types in your program are packed efficiently by showing all types and their sizes and showing the padding bytes that waste space. ''' parser = optparse.OptionParser(description=description, prog='framestats',usage=usage) parser.add_option('-a', '--arch', type='string', dest='arch', help='The architecture to use when creating the debug target.', default=None) parser.add_option('-p', '--platform', type='string', metavar='platform', dest='platform', help='specify one platform by name') parser.add_option('-m', '--module', action='append', type='string', metavar='MODULE', dest='modules', help='Specify one or more modules which will be used to verify the types.', default=[]) parser.add_option('-t', '--type', action='append', type='string', metavar='TYPENAME', dest='typenames', help='Specify one or more type names which should be verified. If no type names are specified, all class and struct types will be verified.', default=[]) parser.add_option('-d', '--debug', action='store_true', dest='debug', help='Pause 10 seconds to wait for a debugger to attach.', default=False) parser.add_option('-v', '--verbose', action='store_true', dest='verbose', default=False) return parser def verify_type (target, type): print type typename = type.GetName() # print 'type: %s' % (typename) (end_offset, padding) = verify_type_recursive (target, type, None, 0, 0, 0) byte_size = type.GetByteSize() # if end_offset < byte_size: # last_member_padding = byte_size - end_offset # print '%+4u <%u> padding' % (end_offset, last_member_padding) # padding += last_member_padding print 'Total byte size: %u' % (byte_size) print 'Total pad bytes: %u' % (padding) if padding > 0: print 'Padding percentage: %2.2f %%' % ((float(padding) / float(byte_size)) * 100.0) def verify_type_recursive (target, type, member_name, depth, base_offset, padding): prev_end_offset = base_offset typename = type.GetName() byte_size = type.GetByteSize() if member_name and member_name != typename: print '%+4u <%3u> %s%s %s;' % (base_offset, type.GetByteSize(), ' ' * depth, typename, member_name) else: print '%+4u <%3u> %s%s' % (base_offset, type.GetByteSize(), ' ' * depth, typename) members = type.members if members: for member_idx, member in enumerate(members): member_type = member.GetType() member_canonical_type = member_type.GetCanonicalType() member_type_class = member_canonical_type.GetTypeClass() member_name = member.GetName() member_offset = member.GetOffsetInBytes() member_total_offset = member_offset + base_offset member_byte_size = member_type.GetByteSize() is_class_or_struct = False if member_type_class == lldb.eTypeClassStruct or member_type_class == lldb.eTypeClassClass: is_class_or_struct = True if member_idx == 0 and member_offset == target.GetAddressByteSize() and type.IsPolymorphicClass(): ptr_size = target.GetAddressByteSize() print '%+4u <%3u> %s__vtbl_ptr_type * _vptr;' % (prev_end_offset, ptr_size, ' ' * (depth + 1)) prev_end_offset = ptr_size else: if prev_end_offset < member_total_offset: member_padding = member_total_offset - prev_end_offset padding = padding + member_padding print '%+4u <%3u> %s' % (prev_end_offset, member_padding, ' ' * (depth + 1)) if is_class_or_struct: (prev_end_offset, padding) = verify_type_recursive (target, member_canonical_type, member_name, depth + 1, member_total_offset, padding) else: prev_end_offset = member_total_offset + member_byte_size if member.IsBitfield(): print '%+4u <%3u> %s%s:%u %s;' % (member_total_offset, member_byte_size, ' ' * (depth + 1), member_type.GetName(), member.GetBitfieldSizeInBits(), member_name) else: print '%+4u <%3u> %s%s %s;' % (member_total_offset, member_byte_size, ' ' * (depth + 1), member_type.GetName(), member_name) if prev_end_offset < byte_size: last_member_padding = byte_size - prev_end_offset print '%+4u <%3u> %s' % (prev_end_offset, last_member_padding, ' ' * (depth + 1)) padding += last_member_padding else: if type.IsPolymorphicClass(): ptr_size = target.GetAddressByteSize() print '%+4u <%3u> %s__vtbl_ptr_type * _vptr;' % (prev_end_offset, ptr_size, ' ' * (depth + 1)) prev_end_offset = ptr_size prev_end_offset = base_offset + type.GetByteSize() return (prev_end_offset, padding) def types_command (debugger, command, result, dict): # Use the Shell Lexer to properly parse up command options just like a # shell would command_args = shlex.split(command) verify_types(debugger, command_args) def verify_types (debugger, command_args): parser = create_types_options() try: (options, args) = parser.parse_args(command_args) except: # if you don't handle exceptions, passing an incorrect argument to the OptionParser will cause LLDB to exit # (courtesy of OptParse dealing with argument errors by throwing SystemExit) result.SetStatus (lldb.eReturnStatusFailed) return "option parsing failed" # returning a string is the same as returning an error whose description is the string if options.debug: print 'Waiting for debugger to attach...' for i in range(10): time.sleep(1) print '.' for path in args: # in a command - the lldb.* convenience variables are not to be used # and their values (if any) are undefined # this is the best practice to access those objects from within a command error = lldb.SBError() target = debugger.CreateTarget (path, options.arch, options.platform, True, error) if error.Fail(): print error.GetCString() continue print target modules = list() if len(options.modules) == 0: # Append just the main executable if nothing was specified module = target.modules[0] if module: modules.append(module) else: for module_name in options.modules: module = lldb.target.module[module_name] if module: modules.append(module) if modules: for module in modules: print 'module: %s' % (module.file) if options.typenames: for typename in options.typenames: print typename types = module.FindTypes(typename) if types.GetSize(): for type in types: verify_type (target, type) else: print 'error: no type matches "%s"' % (typename) else: types = module.GetTypes(lldb.eTypeClassClass | lldb.eTypeClassStruct) for type in types: verify_type (target, type) else: print 'error: no modules' if __name__ == '__main__': debugger = lldb.SBDebugger.Create() verify_types (debugger, sys.argv[1:]) elif getattr(lldb, 'debugger', None): lldb.debugger.HandleCommand('command script add -f types.types_command types') print '"types" command installed, use the "--help" option for detailed help'