Table of Contents
Introduction
The lldb-vscode tool creates a command line tool that implements the Visual
Studio Code Debug API.
It can be installed as an extension for the Visual Studio Code and Nuclide IDE.
The protocol is easy to run remotely and also can allow other tools and IDEs to
get a full featured debugger with a well defined protocol.
Installation for Visual Studio Code
Installing the plug-in involves creating a directory in the ~/.vscode/extensions folder and copying the package.json file that is in the same directory as this
documentation into it, and copying to symlinking a lldb-vscode binary into
the bin directory inside the plug-in directory.
If you want to make a stand alone plug-in that you can send to others on unix systems:
$ mkdir -p ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ cp package.json ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0
$ cd ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ cp /path/to/a/built/lldb-vscode .
$ cp /path/to/a/built/liblldb.so .
If you want to make a stand alone plug-in that you can send to others on macOS systems:
$ mkdir -p ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ cp package.json ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0
$ cd ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ cp /path/to/a/built/lldb-vscode .
$ rsync -av /path/to/a/built/LLDB.framework LLDB.framework
You might need to create additional directories for the liblldb.so or LLDB.framework inside or next to the bin folder depending on how the rpath is set in your lldb-vscode binary. By default the Debug builds of LLDB usually includes
the current executable directory in the rpath, so these steps should work for most people.
To create a plug-in that symlinks into your lldb-vscode in your build directory:
$ mkdir -p ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ cp package.json ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0
$ cd ~/.vscode/extensions/llvm-org.lldb-vscode-0.1.0/bin
$ ln -s /path/to/a/built/lldb-vscode
This is handy if you want to debug and develope the lldb-vscode executable when adding features or fixing bugs.
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
- Attach to an existing process using the process ID
- Attach to an existing process by name
- 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 porgram. Setting this value to ${command:pickMyProcess} will allow interactive process selection in the IDE. |
|
| 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
}