Bugalua

Bugalua is an extension for WinDbg for debugging LuaJIT

It currently allows the user to:

• See the memory usage of a given lua_State object

Bugalua requires the symbols of the LuaJIT library to be loaded.

Using Bugalua

To use Bugalua you need to firs load the file bugalua/bugalua.js from this repository to WinDbg. This can be done by running:

0:000> .scriptload "C:\path_to_Bugalua_repo\bugalua\bugalua.js"
JavaScript script successfully loaded from 'C:\path_to_Bugalua_repo\bugalua\bugalua.js'

Alternatively, you can install Bugalua so that it will be automatically loaded when you run !lua. See next section.

After Bugalua is successfully loaded, you can use it by running !lua <address>:

0:000> !lua 0x25b50378
(lua_State*)0x25b50378                 : 0x25b50378 : [object Object] [Type: lua_State *]
    [<Raw View>]     [Type: lua_State]
    MemoryUsage      : 26.10 KiB (26,724 B)

Or, by just looking at an object of type lua_State*:

0:000> dx (lua_State*)0x25b50378
(lua_State*)0x25b50378                 : 0x25b50378 : [object Object] [Type: lua_State *]
    [<Raw View>]     [Type: lua_State]
    MemoryUsage      : 26.10 KiB (26,724 B)

Installing Bugalua

If you would like to have !lua loaded every time your debugger starts instead of loading the Bugalua manually follow the below steps:

1. Clone this GitHub repository,

2. If you want to install it in the default location (C:\Program Files (x86)\Windows Kits\10\Debuggers\x64), run the file Insttall.ps1 in the root directory of the repository. For any other location, run .\Install.ps1 C:\the_path_to_your_windbg\windbg.exe. This will also work on WinDbg Preview (i.e. WinDbgX.exe).

Compatibility

Bugalua is currently only officialy compatible with these Lua versions:

• LuaJIT 2.0.5 default build (i.e. no LJ_64)

Nevertheless, it might work with other versions as well, if their internal implementation is similar enough.