lldbutil.py

"""
This LLDB module contains miscellaneous utilities.
Some of the test suite takes advantage of the utility functions defined here.
They can also be useful for general purpose lldb scripting.
"""

import lldb
import os, sys
import StringIO

# ===================================================
# Utilities for locating/checking executable programs
# ===================================================

def is_exe(fpath):
    """Returns True if fpath is an executable."""
    return os.path.isfile(fpath) and os.access(fpath, os.X_OK)

def which(program):
    """Returns the full path to a program; None otherwise."""
    fpath, fname = os.path.split(program)
    if fpath:
        if is_exe(program):
            return program
    else:
        for path in os.environ["PATH"].split(os.pathsep):
            exe_file = os.path.join(path, program)
            if is_exe(exe_file):
                return exe_file
    return None

# ===================================================
# Disassembly for an SBFunction or an SBSymbol object
# ===================================================

def disassemble(target, function_or_symbol):
    """Disassemble the function or symbol given a target.

    It returns the disassembly content in a string object.
    """
    buf = StringIO.StringIO()
    insts = function_or_symbol.GetInstructions(target)
    for i in insts:
        print >> buf, i
    return buf.getvalue()


# ==========================================================
# 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 format, just do ba.reverse() on the returned object.
    """
    import struct

    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 = struct.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. For a big endian
    bytearray, just do ba.reverse() on the object before passing it in.
    """
    import struct

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


# ==============================================================
# Get the description of an lldb object or None if not available
# ==============================================================
def get_description(obj, option=None):
    """Calls lldb_obj.GetDescription() and returns a string, or None.

    For SBTarget and SBBreakpointLocation lldb objects, an extra option can be
    passed in to describe the detailed level of description desired:
        o lldb.eDescriptionLevelBrief
        o lldb.eDescriptionLevelFull
        o lldb.eDescriptionLevelVerbose
    """
    method = getattr(obj, 'GetDescription')
    if not method:
        return None
    if isinstance(obj, lldb.SBTarget) or isinstance(obj, lldb.SBBreakpointLocation):
        if option is None:
            option = lldb.eDescriptionLevelBrief

    stream = lldb.SBStream()
    if option is None:
        success = method(stream)
    else:
        success = method(stream, option)
    if not success:
        return None
    return stream.GetData()
        

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

def state_type_to_str(enum):
    """Returns the stateType string given an enum."""
    if enum == lldb.eStateInvalid:
        return "invalid"
    elif enum == lldb.eStateUnloaded:
        return "unloaded"
    elif enum == lldb.eStateConnected:
        return "connected"
    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 StateType enum")

def stop_reason_to_str(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 value_type_to_str(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 get_stopped_threads(process, reason):
    """Returns the thread(s) with the specified stop reason in a list."""
    threads = []
    for t in process:
        if t.GetStopReason() == reason:
            threads.append(t)
    return threads

def get_stopped_thread(process, reason):
    """A convenience function which returns the first thread with the given stop
    reason or None.

    Example usages:

    1. Get the stopped thread due to a breakpoint condition

    ...
        from lldbutil import get_stopped_thread
        thread = get_stopped_thread(self.process, lldb.eStopReasonPlanComplete)
        self.assertTrue(thread != None, "There should be a thread stopped due to breakpoint condition")
    ...

    2. Get the thread stopped due to a breakpoint

    ...
        from lldbutil import get_stopped_thread
        thread = get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
        self.assertTrue(thread != None, "There should be a thread stopped due to breakpoint")
    ...

    """
    threads = get_stopped_threads(process, reason)
    if len(threads) == 0:
        return None
    return threads[0]

def get_threads_stopped_at_breakpoint (process, bkpt):
    """ For a stopped process returns the thread stopped at the breakpoint passed in bkpt"""
    stopped_threads = []
    threads = []

    stopped_threads = get_stopped_threads (process, lldb.eStopReasonBreakpoint)

    if len(stopped_threads) == 0:
        return threads
    
    for thread in stopped_threads:
    # Make sure we've hit our breakpoint...
        break_id = thread.GetStopReasonDataAtIndex (0)
        if break_id == bkpt.GetID():
            threads.append(thread)

    return threads

def continue_to_breakpoint (process, bkpt):
    """ Continues the process, if it stops, returns the threads stopped at bkpt; otherwise, returns None"""
    process.Continue()
    if process.GetState() != lldb.eStateStopped:
        return None
    else:
        return get_threads_stopped_at_breakpoint (process, bkpt)

def get_caller_symbol(thread):
    """
    Returns the symbol name for the call site of the leaf function.
    """
    depth = thread.GetNumFrames()
    if depth <= 1:
        return None
    caller = thread.GetFrameAtIndex(1).GetSymbol()
    if caller:
        return caller.GetName()
    else:
        return None


def get_function_names(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 get_symbol_names(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 get_pc_addresses(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 get_filenames(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 get_line_numbers(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 get_module_names(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 get_stack_frames(thread):
    """
    Returns a sequence of stack frames for this thread.
    """
    def GetStackFrame(i):
        return thread.GetFrameAtIndex(i)

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


def print_stacktrace(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 = get_module_names(thread)
    funcs = get_function_names(thread)
    symbols = get_symbol_names(thread)
    files = get_filenames(thread)
    lines = get_line_numbers(thread)
    addrs = get_pc_addresses(thread)

    if thread.GetStopReason() != lldb.eStopReasonInvalid:
        desc =  "stop reason=" + stop_reason_to_str(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 print_stacktraces(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 thread in process:
        print >> output, print_stacktrace(thread, string_buffer=True)

    if string_buffer:
        return output.getvalue()

# ===================================
# Utility functions related to Frames
# ===================================

def get_parent_frame(frame):
    """
    Returns the parent frame of the input frame object; None if not available.
    """
    thread = frame.GetThread()
    parent_found = False
    for f in thread:
        if parent_found:
            return f
        if f.GetFrameID() == frame.GetFrameID():
            parent_found = True

    # If we reach here, no parent has been found, return None.
    return None

def get_args_as_string(frame):
    """
    Returns the args of the input frame object as a string.
    """
    # arguments     => True
    # locals        => False
    # statics       => False
    # in_scope_only => True
    vars = frame.GetVariables(True, False, False, True) # type of SBValueList
    args = [] # list of strings
    for var in vars:
        args.append("(%s)%s=%s" % (var.GetTypeName(),
                                   var.GetName(),
                                   var.GetValue(frame)))
    if frame.GetFunction().IsValid():
        name = frame.GetFunction().GetName()
    elif frame.GetSymbol().IsValid():
        name = frame.GetSymbol().GetName()
    else:
        name = ""
    return "%s(%s)" % (name, ", ".join(args))

def print_registers(frame, string_buffer = False):
    """Prints all the register sets of the frame."""

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

    print >> output, "Register sets for " + repr(frame)

    registerSet = frame.GetRegisters() # Return type of SBValueList.
    print >> output, "Frame registers (size of register set = %d):" % registerSet.GetSize()
    for value in registerSet:
        #print >> output, value 
        print >> output, "%s (number of children = %d):" % (value.GetName(), value.GetNumChildren())
        for child in value:
            print >> output, "Name: %s, Value: %s" % (child.GetName(), child.GetValue(frame))

    if string_buffer:
        return output.getvalue()

def get_registers(frame, kind):
    """Returns the registers given the frame and the kind of registers desired.

    Returns None if there's no such kind.
    """
    registerSet = frame.GetRegisters() # Return type of SBValueList.
    for value in registerSet:
        if kind.lower() in value.GetName().lower():
            return value

    return None

def get_GPRs(frame):
    """Returns the general purpose registers of the frame as an SBValue.

    The returned SBValue object is iterable.  An example:
        ...
        from lldbutil import get_GPRs
        regs = get_GPRs(frame)
        for reg in regs:
            print "%s => %s" % (reg.GetName(), reg.GetValue())
        ...
    """
    return get_registers(frame, "general purpose")

def get_FPRs(frame):
    """Returns the floating point registers of the frame as an SBValue.

    The returned SBValue object is iterable.  An example:
        ...
        from lldbutil import get_FPRs
        regs = get_FPRs(frame)
        for reg in regs:
            print "%s => %s" % (reg.GetName(), reg.GetValue())
        ...
    """
    return get_registers(frame, "floating point")

def get_ESRs(frame):
    """Returns the exception state registers of the frame as an SBValue.

    The returned SBValue object is iterable.  An example:
        ...
        from lldbutil import get_ESRs
        regs = get_ESRs(frame)
        for reg in regs:
            print "%s => %s" % (reg.GetName(), reg.GetValue())
        ...
    """
    return get_registers(frame, "exception state")