lldbutil.py

"""
This LLDB module contains miscellaneous utilities.
"""

import lldb
import sys
import StringIO

# ==========================================================
# Integer (byte size 1, 2, 4, and 8) to bytearray conversion
# ==========================================================

def int_to_bytearray(val, bytesize):
    """Utility function to convert an integer into a bytearray.

    It returns the bytearray in the little endian format.
    It is easy to get the big endian representation, just do
    ba.reverse() on the returned bytearray object.
    """
    from struct import *

    if bytesize == 1:
        return bytearray([val])

    # Little endian followed by a format character.
    template = "<%c"
    if bytesize == 2:
        fmt = template % 'h'
    elif bytesize == 4:
        fmt = template % 'i'
    elif bytesize == 4:
        fmt = template % 'q'
    else:
        return None

    packed = pack(fmt, val)
    return bytearray(map(ord, packed))

def bytearray_to_int(bytes, bytesize):
    """Utility function to convert a bytearray into an integer.

    It interprets the bytearray in the little endian format.
    It is easy to get the big endian representation, just do
    ba.reverse() on the bytearray object before passing it in.
    """
    from struct import *

    if bytesize == 1:
        return ba[0]

    # Little endian followed by a format character.
    template = "<%c"
    if bytesize == 2:
        fmt = template % 'h'
    elif bytesize == 4:
        fmt = template % 'i'
    elif bytesize == 4:
        fmt = template % 'q'
    else:
        return None

    unpacked = unpack(fmt, str(bytes))
    return unpacked[0]


# ===========================================
# Iterator for lldb aggregate data structures
# ===========================================

def lldb_iter(obj, getsize, getelem):
    """A generator adaptor for lldb aggregate data structures.

    API clients pass in an aggregate object or a container of it, the name of
    the method to get the size of the aggregate, and the name of the method to
    get the element by index.

    Example usages:

    1. Pass an aggregate as the first argument:

    def disassemble_instructions (insts):
        from lldbutil import lldb_iter
        for i in lldb_iter(insts, 'GetSize', 'GetInstructionAtIndex'):
            print i

    2. Pass a container of aggregate which provides APIs to get to the size and
       the element of the aggregate:

    # Module is a container of symbol table 
    module = target.FindModule(filespec)
    for symbol in lldb_iter(module, 'GetNumSymbols', 'GetSymbolAtIndex'):
        name = symbol.GetName()
        ...
    """
    size = getattr(obj, getsize)
    elem = getattr(obj, getelem)
    for i in range(size()):
        yield elem(i)


# =================================================
# Convert some enum value to its string counterpart
# =================================================

def StateTypeString(enum):
    """Returns the stateType string given an enum."""
    if enum == lldb.eStateInvalid:
        return "invalid"
    elif enum == lldb.eStateUnloaded:
        return "unloaded"
    elif enum == lldb.eStateAttaching:
        return "attaching"
    elif enum == lldb.eStateLaunching:
        return "launching"
    elif enum == lldb.eStateStopped:
        return "stopped"
    elif enum == lldb.eStateRunning:
        return "running"
    elif enum == lldb.eStateStepping:
        return "stepping"
    elif enum == lldb.eStateCrashed:
        return "crashed"
    elif enum == lldb.eStateDetached:
        return "detached"
    elif enum == lldb.eStateExited:
        return "exited"
    elif enum == lldb.eStateSuspended:
        return "suspended"
    else:
        raise Exception("Unknown stopReason enum")

def StopReasonString(enum):
    """Returns the stopReason string given an enum."""
    if enum == lldb.eStopReasonInvalid:
        return "invalid"
    elif enum == lldb.eStopReasonNone:
        return "none"
    elif enum == lldb.eStopReasonTrace:
        return "trace"
    elif enum == lldb.eStopReasonBreakpoint:
        return "breakpoint"
    elif enum == lldb.eStopReasonWatchpoint:
        return "watchpoint"
    elif enum == lldb.eStopReasonSignal:
        return "signal"
    elif enum == lldb.eStopReasonException:
        return "exception"
    elif enum == lldb.eStopReasonPlanComplete:
        return "plancomplete"
    else:
        raise Exception("Unknown stopReason enum")

def ValueTypeString(enum):
    """Returns the valueType string given an enum."""
    if enum == lldb.eValueTypeInvalid:
        return "invalid"
    elif enum == lldb.eValueTypeVariableGlobal:
        return "global_variable"
    elif enum == lldb.eValueTypeVariableStatic:
        return "static_variable"
    elif enum == lldb.eValueTypeVariableArgument:
        return "argument_variable"
    elif enum == lldb.eValueTypeVariableLocal:
        return "local_variable"
    elif enum == lldb.eValueTypeRegister:
        return "register"
    elif enum == lldb.eValueTypeRegisterSet:
        return "register_set"
    elif enum == lldb.eValueTypeConstResult:
        return "constant_result"
    else:
        raise Exception("Unknown valueType enum")


# ==================================================
# Utility functions related to Threads and Processes
# ==================================================

def GetFunctionNames(thread):
    """
    Returns a sequence of function names from the stack frames of this thread.
    """
    def GetFuncName(i):
        return thread.GetFrameAtIndex(i).GetFunction().GetName()

    return map(GetFuncName, range(thread.GetNumFrames()))


def GetSymbolNames(thread):
    """
    Returns a sequence of symbols for this thread.
    """
    def GetSymbol(i):
        return thread.GetFrameAtIndex(i).GetSymbol().GetName()

    return map(GetSymbol, range(thread.GetNumFrames()))


def GetPCAddresses(thread):
    """
    Returns a sequence of pc addresses for this thread.
    """
    def GetPCAddress(i):
        return thread.GetFrameAtIndex(i).GetPCAddress()

    return map(GetPCAddress, range(thread.GetNumFrames()))


def GetFilenames(thread):
    """
    Returns a sequence of file names from the stack frames of this thread.
    """
    def GetFilename(i):
        return thread.GetFrameAtIndex(i).GetLineEntry().GetFileSpec().GetFilename()

    return map(GetFilename, range(thread.GetNumFrames()))


def GetLineNumbers(thread):
    """
    Returns a sequence of line numbers from the stack frames of this thread.
    """
    def GetLineNumber(i):
        return thread.GetFrameAtIndex(i).GetLineEntry().GetLine()

    return map(GetLineNumber, range(thread.GetNumFrames()))


def GetModuleNames(thread):
    """
    Returns a sequence of module names from the stack frames of this thread.
    """
    def GetModuleName(i):
        return thread.GetFrameAtIndex(i).GetModule().GetFileSpec().GetFilename()

    return map(GetModuleName, range(thread.GetNumFrames()))


def GetStackFrames(thread):
    """
    Returns a sequence of stack frames for this thread.
    """
    def GetStackFrame(i):
        return thread.GetFrameAtIndex(i)

    return map(GetStackFrame, range(thread.GetNumFrames()))


def PrintStackTrace(thread, string_buffer = False):
    """Prints a simple stack trace of this thread."""

    output = StringIO.StringIO() if string_buffer else sys.stdout
    target = thread.GetProcess().GetTarget()

    depth = thread.GetNumFrames()

    mods = GetModuleNames(thread)
    funcs = GetFunctionNames(thread)
    symbols = GetSymbolNames(thread)
    files = GetFilenames(thread)
    lines = GetLineNumbers(thread)
    addrs = GetPCAddresses(thread)

    if thread.GetStopReason() != lldb.eStopReasonInvalid:
        desc =  "stop reason=" + StopReasonString(thread.GetStopReason())
    else:
        desc = ""
    print >> output, "Stack trace for thread id={0:#x} name={1} queue={2} ".format(
        thread.GetThreadID(), thread.GetName(), thread.GetQueueName()) + desc

    for i in range(depth):
        frame = thread.GetFrameAtIndex(i)
        function = frame.GetFunction()

        load_addr = addrs[i].GetLoadAddress(target)
        if not function.IsValid():
            file_addr = addrs[i].GetFileAddress()
            print >> output, "  frame #{num}: {addr:#016x} {mod}`{symbol} + ????".format(
                num=i, addr=load_addr, mod=mods[i], symbol=symbols[i])
        else:
            print >> output, "  frame #{num}: {addr:#016x} {mod}`{func} at {file}:{line}".format(
                num=i, addr=load_addr, mod=mods[i], func=funcs[i], file=files[i], line=lines[i])

    if string_buffer:
        return output.getvalue()


def PrintStackTraces(process, string_buffer = False):
    """Prints the stack traces of all the threads."""

    output = StringIO.StringIO() if string_buffer else sys.stdout

    print >> output, "Stack traces for " + repr(process)

    for i in range(process.GetNumThreads()):
        print >> output, PrintStackTrace(process.GetThreadAtIndex(i), string_buffer=True)

    if string_buffer:
        return output.getvalue()