# llnode **Repository Path**: mirrors_nodejs/llnode ## Basic Information - **Project Name**: llnode - **Description**: An lldb plugin for Node.js and V8, which enables inspection of JavaScript states for insights into Node.js processes and their core dumps. - **Primary Language**: Unknown - **License**: MIT - **Default Branch**: main - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2020-08-19 - **Last Updated**: 2026-01-17 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README

llnode

[![npm](https://img.shields.io/npm/v/llnode.svg?style=flat-square)](https://npmjs.org/package/llnode) ![ci](https://img.shields.io/github/workflow/status/nodejs/llnode/on%20push%20or%20pull_request/main?style=flat-square) [![coverage](https://img.shields.io/coveralls/github/nodejs/llnode/mmain?style=flat-square)](https://coveralls.io/github/nodejs/llnode) Node.js v10.x+ C++ plugin for the [LLDB](http://lldb.llvm.org) debugger. The llnode plugin adds the ability to inspect JavaScript stack frames, objects, source code and more to the standard C/C++ debugging facilities when working with Node.js processes or core dumps in LLDB. ## Demo https://asciinema.org/a/29589 ## Quick start Start an LLDB session with the llnode plugin automatically loaded: ```bash npm install -g llnode llnode `which node` -c /path/to/core/dump ``` - Never install llnode with `sudo` as it can easily lead to errors during installation and execution. - For more details on starting llnode see the [Usage](#usage) section. - To get started with the llnode commands see the [Commands](#commands) section. ## Install Instructions ### Prerequisites: Official, active Node.js version `llnode` only supports currently active Node.js versions installed via official channels. We recommend installing Node.js with [nvm](https://github.com/nvm-sh/nvm) as it allows users to install global packages without `sudo` by default, and it always installs the official executables from https://nodejs.org. **Do not install Node.js from the default Ubuntu/Debian apt repositories (or from the default repositories of other Linux distributions), llnode is not compatible with Node.js installed that way**. If you still want to install Node.js via `apt-get`, take a look at [nodesource/distributions](https://github.com/nodesource/distributions). ### Prerequisites: Install LLDB and its Library To use llnode you need to have the LLDB debugger installed. The recommended version is LLDB 3.9 and above. - OS X/macOS - You can install [Xcode](https://developer.apple.com/xcode/) and use the LLDB that comes with it. - Optionally, you can install newer versions of lldb using Homebrew with ```bash brew update && brew install --with-lldb --with-toolchain llvm ``` and make sure `/usr/local/opt/llvm/bin` gets searched before `/usr/bin/` on your `PATH`. llnode will link to the LLDB installation returned by `llvm-config` if available. - Linux - You can install the lldb package using the package manager of your distribution. You may need to install additional packages for `liblldb` as well. - For example, on Ubuntu 18.04 you can install the prerequisites with ```bash apt-get install lldb-8 liblldb-8-dev ``` - FreeBSD ```bash # Install llvm with lldb and headers pkg install llvm39 rm -f /usr/bin/lldb ln -s /usr/local/bin/lldb39 /usr/bin/lldb ``` - Windows - You can install a [binary distribution of LLVM](http://releases.llvm.org/download.html) directly or using [Chocolatey](https://chocolatey.org/install#installing-chocolatey): ```bat cinst -y visualstudio2017buildtools visualstudio2017-workload-vctools llvm git ``` Visual Studio is required for MSBuild and headers when building llnode. Git is required to download the lldb headers. - Android / Termux (Experimental) - Install Termux (https://termux.com) - Install Termux Packages - pkg install clang lldb lldb-dev make - pkg install nodejs-lts nodejs-lts-dev - To debug: ``` llnode -- /data/data/com.termux/files/usr/bin/node --abort_on_uncaught_exception script.js (llnode) run ``` ### Install the Plugin #### Install llnode globally via npm If you have `lldb` available on your `PATH`, simply run: ```bash npm install -g llnode ``` To build llnode against a specific lldb version matching an lldb executable, use the `--lldb_exe` npm option. For example, on Linux the executable on the `PATH` might be `lldb-3.9`: ```bash npm install --lldb_exe=`which lldb-3.9` -g llnode ``` After installing with npm, `llnode` should be available on your `PATH` as a shortcut for running LLDB with the llnode plugin. #### Optional: Install with Homebrew (OS X/macOS) ```bash brew install llnode ``` ## Loading the llnode Plugin There are several ways to load the llnode plugin: ### 1. Using the llnode shortcut If you install llnode globally via npm (`npm install -g llnode`), you can use the `llnode` shortcut script. This starts `lldb` and automatically issues the `plugin load` command. All parameters to the llnode script are passed directly to lldb. If you it's not a local installation, the shortcut will be in `node_modules/.bin/llnode`. ### 2. Using `~/.lldbinit` to load the Plugin Automatically To tell LLDB to load llnode automatically regardless of the version of lldb that you are running, add this line to `~/.lldbinit`: ``` plugin load /path/to/the/llnode/plugin ``` The path to the llnode plugin should be printed when the installation is finished. On OS X/macOS the plugin is typically `node_modules/llnode/llnode.dylib`, on Linux it's `node_modules/llnode/llnode.so`. ### 3. Loading the Plugin Manually The llnode plugin can also be manually loaded into LLDB using the `plugin load` command within lldb. It does not matter whether the `plugin load` command is issued before or after loading a core dump or attaching to a process. ### 4. Install the Plugin to the LLDB System Plugin Directory Similar to the `~/.lldbinit` approach, this way LLDB will also load the plugin automatically on start-up. Doing this may require additional permissions to be able to copy the plugin library to the system plugin directory. On Linux, run `make install-linux` in the project directory, or if installing with npm, copy `node_modules/llnode/llnode.so` to `/usr/lib/lldb/plugins` or create a link there. On OS X/macOS, run `make install-osx` in the project directory, or if installing with npm, copy `node_modules/llnode/llnode.dylib` to `~/Library/Application\ Support/LLDB/PlugIns/` or create a link there. # Usage To use llnode with a core dump the core dump needs to be loaded into lldb along with the exact executable that created the core dump. The executable contains information that lldb and the llnode plugin need to make sense of the data in the core dump. To load a core dump when starting llnode use: ``` llnode /path/to/bin/node -c /path/to/core ``` or to load the core dump after starting lldb: ``` (llnode) target create /path/to/bin/node -c /path/to/core ``` To use llnode against a live process: ``` llnode -- /path/to/bin/node script.js (llnode) run ``` This is ideal for debugging an npm package with native code. To debug a Node.js crash on uncaught exception: ``` llnode -- /path/to/bin/node --abort_on_uncaught_exception script.js (llnode) run ``` lldb will stop your process when it crashes. To see where it stopped use the v8 bt command. See the [Commands](#commands) section below for more commands. ### Commands ``` (llnode) v8 help Node.js helpers Syntax: v8 The following subcommands are supported: bt -- Show a backtrace with node.js JavaScript functions and their args. An optional argument is accepted; if that argument is a number, it specifies the number of frames to display. Otherwise all frames will be dumped. Syntax: v8 bt [number] findjsinstances -- List every object with the specified type name. Use -v or --verbose to display detailed `v8 inspect` output for each object. Accepts the same options as `v8 inspect` findjsobjects -- List all object types and instance counts grouped by typename and sorted by instance count. Use -d or --detailed to get an output grouped by type name, properties, and array length, as well as more information regarding each type. findrefs -- Finds all the object properties which meet the search criteria. The default is to list all the object properties that reference the specified value. Flags: * -v, --value expr - all properties that refer to the specified JavaScript object (default) * -n, --name name - all properties with the specified name * -s, --string string - all properties that refer to the specified JavaScript string value getactivehandles -- Print all pending handles in the queue. Equivalent to running process._getActiveHandles() on the living process. getactiverequests -- Print all pending requests in the queue. Equivalent to running process._getActiveRequests() on the living process. inspect -- Print detailed description and contents of the JavaScript value. Possible flags (all optional): * -F, --full-string - print whole string without adding ellipsis * -m, --print-map - print object's map address * -s, --print-source - print source code for function objects * -l num, --length num - print maximum of `num` elements from string/array Syntax: v8 inspect [flags] expr nodeinfo -- Print information about Node.js print -- Print short description of the JavaScript value. Syntax: v8 print expr source list -- Print source lines around the currently selected JavaScript frame. Syntax: v8 source list [flags] Flags: * -l - Print source code below line . For more help on any particular subcommand, type 'help '. ``` ## Develop and Test ### Configure and Build The easiest way to build the plugin: ```bash # Clone this repo git clone https://github.com/nodejs/llnode.git && cd llnode # Configure and build the plugin with npm npm install # To configure and build the plugin without npm node scripts/configure.js && node scripts/install.js && node scripts/cleanup.js # Or use make make plugin # To configure and build both the plugin and the addon npm install --llnode_build_addon=true # To configure and build with a specific path to headers npm install --llnode_lldb_include_dir=/path/to/lldb/include # Without npm LLNODE_BUILD_ADDON=true node scripts/configure.js && node scripts/install.js && node scripts/cleanup.js # Or use make make addon # Builds the addon make # Builds both the addon and the plugin ``` To configure the build yourself: ```bash # Detect available lldb installation and download headers if necessary node scripts/configure.js # To build the addon, set the environment variable LLNODE_BUILD_ADDON=true # To configure with the detected lldb installation node-gyp configure # To configure with a specified path to headers, where `$lldb_include_dir` # contains the headers node-gyp configure -- -Dlldb_include_dir=/usr/local/Cellar/llvm/5.0.0/include # To configure with a specified path to the libraries, where `$lldb_lib_dir` # contains `liblldb.so` or `liblldb.dylib` node-gyp configure -- -Dlldb_lib_dir=/usr/lib/llvm-3.9/lib # Build the plugin (and the addon if LLNODE_BUILD_ADDON=true) node-gyp build # Move the built plugin to the project directory node scripts/cleanup.js ``` ### Test To run the tests, if `lldb` is an executable on the `PATH`: ```bash npm run test-all # Run both addon and plugin tests npm run test-plugin # Run plugin tests npm run test-addon # Run addon tests ``` If the LLDB executable is named differently, point `TEST_LLDB_BINARY` to it before running the tests: ```bash TEST_LLDB_BINARY=`which lldb-4.0` npm run test-all ``` ### Useful Environment Variables * `LLNODE_DEBUG=true` to see additional debug info from llnode * `TEST_LLNODE_DEBUG=true` to see additional debug info coming from the tests * `LLNODE_CORE=/path/to/core/dump LLNODE_NODE_EXE=/path/to/node` to use a prepared core dump instead of generating one on-the-fly when running the tests. For example, to inspect the process of `inspect-scenario.js`, run: ```bash LLNODE_DEBUG=true lldb -- \ node --abort_on_uncaught_exception --expose_externalize_string \ test/fixtures/inspect-scenario.js (lldb) run ``` To debug `test/scan-test.js` with a prepared core dump: ``` LLNODE_DEBUG=true TEST_LLNODE_DEBUG=true \ LLNODE_CORE=/path/to/core/dump/of/inspect/scenario.js \ LLNODE_NODE_EXE=/path/to/node \ node test/scan-test.js ``` ## LICENSE This software is licensed under the MIT License. Copyright Fedor Indutny, 2016. 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.