name : lldb_commands.py # Copyright 2017 the V8 project authors. All rights reserved. # Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. # Load this file by adding this to your ~/.lldbinit: # command script import <this_dir>/lldb_commands.py # for py2/py3 compatibility from __future__ import print_function import os import re import lldb ##################### # Helper functions. # ##################### def current_thread(debugger): return debugger.GetSelectedTarget().GetProcess().GetSelectedThread() def current_frame(debugger): return current_thread(debugger).GetSelectedFrame() def no_arg_cmd(debugger, cmd, print_error=True): cast_to_void_expr = '(void) {}'.format(cmd) evaluate_result = current_frame(debugger).EvaluateExpression(cast_to_void_expr) # When a void function is called the return value type is 0x1001 which # is specified in http://tiny.cc/bigskz. This does not indicate # an error so we check for that value below. kNoResult = 0x1001 result = evaluate_result.GetError() is_success = not result.fail or result.value == kNoResult if not is_success: if print_error: print("Failed to evaluate command {} :".format(cmd)) print(result.description) else: print("") return (is_success, result, cmd) def ptr_arg_cmd(debugger, name, param, cmd, print_error=True): if not param: print("'{}' requires an argument".format(name)) return (False, None, "") param = '(void*)({})'.format(param) return no_arg_cmd(debugger, cmd.format(param), print_error) def print_handle(debugger, command_name, param, print_func): value = current_frame(debugger).EvaluateExpression(param) result = print_func(value) if not result[0]: print("{} cannot print a value of type {}".format(command_name, value.type.name)) return result def print_direct(debugger, command_name, value): CMD = "_v8_internal_Print_Object((v8::internal::Address*)({}))" return ptr_arg_cmd(debugger, command_name, value, CMD.format(value)) def print_indirect(debugger, command_name, value): CMD = "_v8_internal_Print_Object(*(v8::internal::Object**)({}))" return ptr_arg_cmd(debugger, command_name, value, CMD.format(value)) V8_LLDB_COMMANDS = [] def lldbCommand(fn): V8_LLDB_COMMANDS.append(fn.__name__) return fn ##################### # lldb commands. # ##################### @lldbCommand def job(debugger, param, *args): """Print a v8 heap object""" ptr_arg_cmd(debugger, 'job', param, "_v8_internal_Print_Object({})") @lldbCommand def jh(debugger, param, *args): """Print v8::internal::(Maybe)?(Direct|Indirect)?Handle value""" def print_func(value): # Indirect handles contain a location_. field = value.GetValueForExpressionPath(".location_") if field.IsValid(): return print_indirect(debugger, 'jh', field.value) # Direct handles contain a obj_. field = value.GetValueForExpressionPath(".obj_") if field.IsValid(): return print_indirect(debugger, 'jh', field.value) # We don't know how to print this... return (False, None, "") return print_handle(debugger, 'jh', param, print_func) @lldbCommand def jlh(debugger, param, *args): """Print v8::(Maybe)?Local value""" def print_func(value): # After https://crrev.com/c/4335544, v8::MaybeLocal contains a local_. field = value.GetValueForExpressionPath(".local_") if field.IsValid(): value = field # After https://crrev.com/c/4335544, v8::Local contains a location_. field = value.GetValueForExpressionPath(".location_") if field.IsValid(): return print_indirect(debugger, 'jlh', field.value) # Before https://crrev.com/c/4335544, v8::Local contained a val_. field = value.GetValueForExpressionPath(".val_") if field.IsValid(): return print_indirect(debugger, 'jlh', field.value) # With v8_enable_direct_local=true, v8::Local contains a ptr_. field = value.GetValueForExpressionPath(".ptr_") if field.IsValid(): return print_direct(debugger, 'jlh', field.value) # We don't know how to print this... return (False, None, "") return print_handle(debugger, 'jlh', param, print_func) @lldbCommand def jl(debugger, param, *args): """Print v8::Local handle value""" return jlh(debugger, param, *args) @lldbCommand def jco(debugger, param, *args): """Print the code object at the given pc (default: current pc)""" if not param: param = str(current_frame(debugger).FindRegister("pc").value) ptr_arg_cmd(debugger, 'jco', param, "_v8_internal_Print_Code({})") @lldbCommand def jtt(debugger, param, *args): """Print the transition tree of a v8 Map""" ptr_arg_cmd(debugger, 'jtt', param, "_v8_internal_Print_TransitionTree({})") @lldbCommand def jst(debugger, *args): """Print the current JavaScript stack trace""" no_arg_cmd(debugger, "_v8_internal_Print_StackTrace()") @lldbCommand def jss(debugger, *args): """Skip the jitted stack on x64 to where we entered JS last""" frame = current_frame(debugger) js_entry_sp = frame.EvaluateExpression( "v8::internal::Isolate::Current()->thread_local_top()->js_entry_sp_;") \ .GetValue() sizeof_void = frame.EvaluateExpression("sizeof(void*)").GetValue() rbp = frame.FindRegister("rbp") rsp = frame.FindRegister("rsp") pc = frame.FindRegister("pc") rbp = js_entry_sp rsp = js_entry_sp + 2 *sizeof_void pc.value = js_entry_sp + sizeof_void @lldbCommand def bta(debugger, *args): """Print stack trace with assertion scopes""" func_name_re = re.compile("([^(<]+)(?:\(.+\))?") assert_re = re.compile( "^v8::internal::Per\w+AssertType::(\w+)_ASSERT, (false|true)>") thread = current_thread(debugger) for frame in thread: functionSignature = frame.GetDisplayFunctionName() if functionSignature is None: continue functionName = func_name_re.match(functionSignature) line = frame.GetLineEntry().GetLine() sourceFile = frame.GetLineEntry().GetFileSpec().GetFilename() if line: sourceFile = sourceFile + ":" + str(line) if sourceFile is None: sourceFile = "" print("[%-2s] %-60s %-40s" % (frame.GetFrameID(), functionName.group(1), sourceFile)) match = assert_re.match(str(functionSignature)) if match: if match.group(3) == "false": prefix = "Disallow" color = "\033[91m" else: prefix = "Allow" color = "\033[92m" print("%s -> %s %s (%s)\033[0m" % ( color, prefix, match.group(2), match.group(1))) def setup_source_map_for_relative_paths(debugger): # Copied from Chromium's tools/lldb/lldbinit.py. # When relative paths are used for debug symbols, lldb cannot find source # files. Set up a source map to point to V8's root. this_dir = os.path.dirname(os.path.abspath(__file__)) source_dir = os.path.join(this_dir, os.pardir) debugger.HandleCommand( 'settings set target.source-map ../.. ' + source_dir) def __lldb_init_module(debugger, dict): setup_source_map_for_relative_paths(debugger) debugger.HandleCommand('settings set target.x86-disassembly-flavor intel') for cmd in V8_LLDB_COMMANDS: debugger.HandleCommand( 'command script add -f lldb_commands.{} {}'.format(cmd, cmd))