LLDB utilities

.lldbinit

# Shortcuts to force execution in an Objective-C context instead of Swift (assuming current context is Swift)
command alias eobjc e -l objc
command alias pobjc e -l objc --
command alias poobjc e -l objc -O --

# Call while paused on closing } of a function to print return value
# TODO: Fix this, as $rax doesn't seem to be recognized anymore
# command alias retval p $rax

# Usage: let <variable-name> <memory-address> <type-name>
# 
#     variable-name: Name of variable to define (must start with $ to be persisted after completion of this command)
#     memory-address: Pointer to data
#     type-name: Name of type represented by the data at the given pointer
#
# Example:
#     (lldb) let $foo 0x12345 UIView
#     => Executes `e let $foo = unsafeBitCast(0x12345, to: UIView.self)`
command regex let 's/^([$A-Za-z0-9]+) +(0x[0-9a-f]+) +([A-Za-z0-9.]+)$/e let %1 = unsafeBitCast(%2, to: %3.self)/'

# Usage: j [+-]
#
#     +-: + to jump forward, - to jump backward
#     n: Number of lines to jump
#
# Example:
#     (lldb) j +2
#     => Jumps forward by 2 lines (executes `thread jump --by 2`)
#
#     (lldb) j -2
#     => Jumps backward by 2 lines (executes `thread jump --by -2`)
command regex j 's/^([\+-])([0-9]+)$/th jump --by %1%2/'

# Run AutoLayout trace on the view at the specified address
#
# Usage: autolayouttrace <memory-address>
command regex autolayouttrace 's/(.*)/e -l objc -O -- [(UIView *)%1 _autolayoutTrace]/'

# Refresh view hierarchy while paused by flushing the CATransaction queue
command alias refresh e CATransaction.flush()

command script import ~/.lldb/custom_lldb_commands.py

custom_lldb_commands.py

import lldb
import os

# Copy a variable from Swift LLDB context to Objective-C context
# Usage: swifttoobjc <variable> [<type>] [<name for objc variable>]
# E.g.,
#   swifttoobjc foo // Creates variable named `$foo` with same type as Swift variable `foo`.
#   swifttoobjc foo UIView $bar // Creates variable named `$bar` with type `UIView`.
@lldb.command("swifttoobjc")
def copy_swift_to_objc(debugger, command, exe_ctx, result, internal_dict):
    frame = exe_ctx.GetFrame()

    args = command.split(" ")
    swift_name = args[0]
    try:
        type_name = args[1]
    except IndexError:
        type_name = _get_value(
            frame.EvaluateExpression("String(describing: type(of: {0}))".format(swift_name))
        )
    try:
        objc_name = args[2]
    except IndexError:
        objc_name = swift_name if swift_name.startswith("$") else ("$" + swift_name)

    address = _get_value(
        frame.EvaluateExpression(
            "String(format: \"%p\", unsafeBitCast({0}, to: Int.self))".format(swift_name)
        )
    )

    _execute_lldb(
        debugger,
        "e -l objc -- {0} *{1} = ({0} *){2};".format(type_name, objc_name, address)
    )

    # Show confirmation of success by printing the new Objective-C variable
    _execute_lldb(
        debugger,
        "e -l objc -O -- {0}".format(objc_name)
    )

# Copy a variable from Objective-C LLDB context to Swift context
# Usage: objctoswift <variable> [<type>] [<name for swift variable>]
# E.g.,
#   objctoswift foo // Creates variable named `$foo` with same type as Objective-C variable `foo`.
#   objctoswift foo UIView $bar // Creates variable named `$bar` with type `UIView`.
@lldb.command("objctoswift")
def copy_objc_to_swift(debugger, command, exe_ctx, result, internal_dict):
    frame = exe_ctx.GetFrame()

    args = command.split(" ")
    objc_name = args[0]
    try:
        type_name = args[1]
    except IndexError:
        type_name = _get_value(
            frame.EvaluateExpression("{0}.description".format(objc_name))
        )
    try:
        swift_name = args[2]
    except IndexError:
        swift_name = objc_name if objc_name.startswith("$") else ("$" + objc_name)

    address = _get_value(
        frame.EvaluateExpression(
            "[NSString stringWithFormat:@\"%p\", {0}]".format(objc_name)
        )
    )

    _execute_lldb(
        debugger,
        "e -l swift -- let {0} = unsafeBitCast({1}, to: {2}.self)".format(swift_name, address,  type_name)
    )

    # Show confirmation of success by printing the new Swift variable
    _execute_lldb(
        debugger,
        "e -l swift -O -- {0}".format(swift_name)
    )

# Execute a Swift source file
# Usage: execute_swift <path>
# E.g.,
#   execute_swift ~/MySwiftUtilities.swift
@lldb.command("execute_swift")
def execute_swift(debugger, path, ctx, result, _):
    with open(os.path.expanduser(path)) as f:
        contents = f.read()

    print(contents)
    options = lldb.SBExpressionOptions()
    options.SetLanguage(lldb.eLanguageTypeSwift)
    ctx.frame.EvaluateExpression(contents, options)
#    _execute_lldb(debugger, "expression -l swift -- {0}".format(contents))

def index_path_summary(value, internal_dict):
    frame = value.GetFrame()
    name = value.GetName()
    section = frame.EvaluateExpression("{0}.section".format(name)).GetValueAsSigned()
    item = frame.EvaluateExpression("{0}.item".format(name)).GetValueAsSigned()
    return "(Section: {0}, Item: {1})".format(section, item)

def _get_value(sb_value):
    # Trim trailing newline and enclosing double quotes.
    return sb_value.description[1:-2]

def _execute_lldb(debugger, command):
    print(command)
    debugger.HandleCommand(command)

def __lldb_init_module(debugger, internal_dict):
    debugger.HandleCommand("type summary add -F " + __name__ + ".index_path_summary IndexPath")

license

MIT License

Copyright (c) 2022 Kevin Beaulieu

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.