NOTE: This is no longer supported and deprecated

Table of Contents

• Introduction
• Installation
• Configurations
  • Launch Configuration Settings
  • Attach Configuration Settings
  • Example configurations
    • Launching
    • Attach to process using process ID
    • Attach to process by name
    • Loading a core file

Introduction

The lldb-vscode extension packages the command line tool of the same name that implements the Visual Studio Code Debug API.

lldb-vscode has two unique features. The first is that it launches lldb's CommandInterpreter in a Terminal pane instead of shoehorning the CommandInterpreter into the Debug Console as many other VSCode debug adapters do.

The second is the poorly named "LLDB: Free Launch" command. This launches lldb and just lets you have access to the command line prompt with no target. You can then use lldb as you normally would on the command line (e.g. target create a.out & b main & run) at which point VSCode will update with the current target once it's there.

NOTE: This does not work entirely properly yet. I still need to implement this in lldb itself. For now, it just checks for a file /tmp/lldbmarker and sleeps until it exists at which point it continues. I suggest adding

command alias mark script import os; os.system("touch /tmp/lldbmarker")

to your ~/.lldbinit-lldb-vscode file. With this, you can simply write

(lldb) file a.out
(lldb) b main
(lldb) r
(lldb) mark

Configurations

Launching to attaching require you to create a launch configuration. This file defines arguments that get passed to lldb-vscode and the configuration settings control how the launch or attach happens.

Launch Configuration Settings

When you launch a program with Visual Studio Code you will need to create a launch.json file that defines how your program will be run. The JSON configuration file can contain the following lldb-vscode specific launch key/value pairs:

parameter	type	req
name	string	Y	A configuration name that will be displayed in the IDE.
type	string	Y	Must be "lldb-vscode".
request	string	Y	Must be "launch".
program	string	Y	Path to the executable to launch.
args	[string]		An array of command line argument strings to be passed to the program being launched.
cwd	string		The program working directory.
env	dictionary		Environment variables to set when launching the program. The format of each environment variable string is "VAR=VALUE" for environment variables with values or just "VAR" for environment variables with no values.
stopOnEntry	boolean		Whether to stop program immediately after launching.
initCommands	[string]		LLDB commands executed upon debugger startup prior to creating the LLDB target. Commands and command output will be sent to the debugger console when they are executed.
preRunCommands	[string]		LLDB commands executed just before launching after the LLDB target has been created. Commands and command output will be sent to the debugger console when they are executed.
stopCommands	[string]		LLDB commands executed just after each stop. Commands and command output will be sent to the debugger console when they are executed.
exitCommands	[string]		LLDB commands executed when the program exits. Commands and command output will be sent to the debugger console when they are executed.
sourceMap	[string[2]]		Specify an array of path re-mappings. Each element in the array must be a two element array containing a source and destination pathname.
debuggerRoot	string		Specify a working directory to use when launching lldb-vscode. If the debug information in your executable contains relative paths, this option can be used so that lldb-vscode can find source files and object files that have relative paths.

Attaching Settings

When attaching to a process using LLDB you can attach in a few ways

1. Attach to an existing process using the process ID
2. Attach to an existing process by name
3. Attach by name by waiting for the next instance of a process to launch

The JSON configuration file can contain the following lldb-vscode specific launch key/value pairs:

parameter	type	req
name	string	Y	A configuration name that will be displayed in the IDE.
type	string	Y	Must be "lldb-vscode".
request	string	Y	Must be "attach".
program	string		Path to the executable to attach to. This value is optional but can help to resolve breakpoints prior the attaching to the program.
pid	number		The process id of the process you wish to attach to. If pid is omitted, the debugger will attempt to attach to the program by finding a process whose file name matches the file name from program.
stopOnEntry	boolean		Whether to stop program immediately after launching.
waitFor	boolean		Wait for the process to launch.
initCommands	[string]		LLDB commands executed upon debugger startup prior to creating the LLDB target. Commands and command output will be sent to the debugger console when they are executed.
preRunCommands	[string]		LLDB commands executed just before launching after the LLDB target has been created. Commands and command output will be sent to the debugger console when they are executed.
stopCommands	[string]		LLDB commands executed just after each stop. Commands and command output will be sent to the debugger console when they are executed.
exitCommands	[string]		LLDB commands executed when the program exits. Commands and command output will be sent to the debugger console when they are executed.
attachCommands	[string]		LLDB commands that will be executed after preRunCommands which take place of the code that normally does the attach. The commands can create a new target and attach or launch it however desired. This allows custom launch and attach configurations. Core files can use target create --core /path/to/core to attach to core files.

Example configurations

Launching

This will launch /tmp/a.out with arguments one, two, and three and adds FOO=1 and bar to the environment:

{
"type": "lldb-vscode",
"request": "launch",
"name": "Debug",
"program": "/tmp/a.out",
"args": [ "one", "two", "three" ],
"env": [ "FOO=1", "BAR" ],
}

Attach using PID

This will attach to a process a.out whose process ID is 123:

{
"type": "lldb-vscode",
"request": "attach",
"name": "Attach to PID",
"program": "/tmp/a.out",
"pid": 123
}

Attach by Name

This will attach to an existing process whose base name matches a.out. All we have to do is leave the pid value out of the above configuration:

{
"name": "Attach to Name",
"type": "lldb-vscode",
"request": "attach",
"program": "/tmp/a.out",
}

If you want to ignore any existing a.out processes and wait for the next instance to be launched you can add the "waitFor" key value pair:

{
"name": "Attach to Name (wait)",
"type": "lldb-vscode",
"request": "attach",
"program": "/tmp/a.out",
"waitFor": true
}

This will work as long as the architecture, vendor and OS supports waiting for processes. Currently MacOS is the only platform that supports this.

Loading a Core File

Loading a core file can use the "attach" request along with the "attachCommands" to implement a custom attach:

{
"name": "Attach to Name (wait)",
"type": "lldb-vscode",
"request": "attach",
"attachCommands": ["target create -c /path/to/123.core /path/to/executable"],
"stopOnEntry": false
}