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    llnode

    3.2.0 • Public • Published

    llnode

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    Node.js v10.x+ C++ plugin for the LLDB 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:

    npm install -g llnode
    llnode `which node` -c /path/to/core/dump
    • For more details on starting llnode see the Usage section.
    • To get started with the llnode commands see the Commands section.

    Install Instructions

    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 and use the LLDB that comes with it.

      • Optionally, you can install newer versions of lldb using Homebrew with

        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 16.04 you can install the prerequisites with

        apt-get install lldb-4.0 liblldb-4.0-dev
    • FreeBSD

      # 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 directly or using Chocolatey:

        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:

    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:

    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)

    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 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 <line> - Print source code below line <line>.
    
    For more help on any particular subcommand, type 'help <command> <subcommand>'.
    

    Develop and Test

    Configure and Build

    The easiest way to build the plugin:

    # 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:

    # 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 `$lldb_include_dir` 
    # contains the <lldb/*/*.h> headers 
    node-gyp configure -- -Dlldb_include_dir=/usr/local/Cellar/llvm/5.0.0/include
    # To configure with a specified path to the libraries, where `$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:

    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:

    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:

    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.

    Install

    npm i llnode

    DownloadsWeekly Downloads

    180

    Version

    3.2.0

    License

    MIT

    Unpacked Size

    369 kB

    Total Files

    47

    Last publish

    Collaborators

    • hhellyer
    • indutny
    • joyeecheung
    • nodejs-foundation
    • rnchamberlain