Debug c++ GDExtension

Sox

Haystack yes, everything works fine.

YanDaik

Can someone provide step by step instruction please?
Do i need to compile both godot and extension with dev_build=yes?
How do I set pdb files both for godot and extension in studio?

do I need to add these lines?

if env["target"] == "debug":
env.Append(CPPDEFINES=["DEBUG_ENABLED", "DEBUG_METHODS_ENABLED"])

YanDaik

I've managed to get debugging symbols in engine code by compiling it with dev_build=yes.
But cant get debugging working for extension even compiling it with dev_build=yes. Does anyone know how to make visual studio look for dll debugging symbols?

TwistedTwigleg

You may want to ask on the Godot chat in the Godot community tab on the main Godot site, as the Godot developers are more frequent there and they’d likely have more information on GDExtensions.

Haystack

Yan, did you see my previous comment in this thread? Repeated here: "You may also need to tell your debugger where to find the godot pdb file. e.g. for my gd_extension testing, I copied the godot pdb file to the same directory as my extension dll.'

Haystack

Does anyone know how to make visual studio look for dll debugging symbols?

Copying the godot pdb to your bin directory should work, but you have to do it for every project you want to debug. If you want a more general solution:

https://learn.microsoft.com/en-us/visualstudio/debugger/specify-symbol-dot-pdb-and-source-files-in-the-visual-studio-debugger?view=vs-2022

In Visual Studio 2019, select menu "Tools >> Options"
In the Options dialog, on the left-hand column, select "Debugging >> Symbols"
On the top right-hand side of the options dialog, select the "+" symbol to add a search directory. Enter the path to the 'bin' directory where you built the Godot game engine, (on my system, it's "D:\Godot\godot\bin", but it will be different on each system) (Double check that the pdb file exists in this directory. If not, rebuild Godot with symbols enabled)
Start the debugger.

YanDaik

I've figured out how to debug gdetension with Visual Studio (or Rider).
1. First you need to compile your engine and your extension with dev_build=yes
2. You'll get dll with "dev" name in it. Provide path to it i your extension file.
3. Create an empty Visual Studio solution. And an empty NMake project.
4. Setup studio to build your code for you with debug button. Type in NMake tab of project properties, in the "build command line" the command: scons dev_build=yes. This way studio will compile project for you.
5. In the Dedugger tab set launch command to "$your_path\godot.windows.editor.dev.x86_64.exe"
6. Set command line arguments with "--path" command that will tell engine to start game immediately. like this: --path "$(SolutionDir)../"
6.a. If you'll provide in argument path to your godot.project engine will start in editor mode. Thats fine if you want to debug editor, but if you'll start game from the editor the c++ debugger wont attach to it. For debugging editor I've created another NMake configuration for it.
6.b. Probably a studio bug, but in order to intell issence to see godot-cpp code it wants its path to be included in "additional include" field of c++ configuration tab which is missing in NMake configuration. you might want to switch to c++ configuration, add additional includes path that lead to godot-cpp source, and then switch back to NMake. Or you can manually edit project file in text editor by adding there something like (in my case):

<ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='GDExt|x64'">
    <ClCompile>
      <AdditionalIncludeDirectories>$(SolutionDir)godot-cpp\gdextension;$(SolutionDir)godot-cpp\include;$(SolutionDir)godot-cpp\gen\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
    </ClCompile>
  </ItemDefinitionGroup>

7. That pretty much it. you are ready to go. you can also add godot engine project to your solution if you want. this way you don't need to copy pdb anywhere (it did not work for me anyway)

whiletrue111

YanDaik
Thanks ...
Do i have to compile the godot engine ? to able to debug my extension ? isn't compiling just the godot-cpp with debug is enough?

dimon4eg

@YanDaik thanks a lot! You greatly helped me!

My little addition is just setting C++17 standard for proper work of IntelliSense:

<ItemDefinitionGroup>
    <ClCompile>
        <AdditionalIncludeDirectories>$(SolutionDir)godot-cpp\gdextension;$(SolutionDir)godot-cpp\include;$(SolutionDir)godot-cpp\gen\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
        <LanguageStandard>stdcpp17</LanguageStandard>
    </ClCompile>
</ItemDefinitionGroup>

I'm able to debug and even code in Visual Studio 😃

van800

I am finishing work on sln generation improvement for the godot itself.
https://github.com/godotengine/godot/pull/103405
Same approach can be used for the GDExtensions to use Rider outside Windows.

sian2005

For those unlucky enough to stumble upon this issue, and are using Visual Studio Code, I have set up some configurations that might help you debug your GDExtension. This is the method that works for me, which is greatly inspired by @YanDaik:

Recompile the Godot Engine using debug symbols with scons dev_build=yes

Create your custom launch.json file in the .vscode folder. Mine looks like this:

{
    "configurations": [
        {
            "name": "(Windows) Debug GDExtension",
            "type": "cppvsdbg",
            "request": "launch",
            "console": "integratedTerminal",
            "cwd": "${workspaceRoot}/demo",
            "program": "C:\\Users\\sian2005\\C\\godot\\bin\\godot.windows.editor.dev.x86_64.exe",
            "args": ["--upwards", "--headless", "--quit"],
            "stopAtEntry": false,
            "environment": [],
            "preLaunchTask": "build-scons"
        }
    ],
    "version": "2.0.0"
}

Where you will have to replace C:\\Users\\sian2005\\C\\godot\\bin\\godot.windows.editor.dev.x86_64.exe with your path to your compiled Godot Engine, and the cwd path to where your demo project is. This can be found in the godot/bin/godot.windows.editor.dev.x86_64.exe where godot is my clone of the Godot repository. Additionally, if you run Mac or Linux, you can replace cppvsdbg with cppdbg, and change the name of the configuration accordingly.

Next, as defined in the preLaunchTask, we need an additional task for compiling your GDExtension. This task is defined in the tasks.json, also in the .vscode folder. Mine looks like this:

{
    "tasks": [
        {
            "label": "build-scons",
            "type": "process",
            "command": "scons",
            "args": ["dev_build=yes"],
            "options": {
                "cwd": "${workspaceFolder}"
            }
        }
    ],
    "version": "2.0.0"
}

Which should require no changes, unless you have your SConstruct file not in your workspace root, which can be easily adjusted for by appending that path to the cwd (working directory) so scons can find it.

Finally, we'll need to update the .gdextension file in your godot project root folder. Here, you will have defined your library builds under [libraries]. Adjust your libraries to the .dev version of them. Mine look as follows:

...
[libraries]

windows.debug.x86_64 = "res://bin/libgdwfc.windows.template_debug.dev.x86_64.dll"
...

Place a breakpoint anywhere in your code, run this configuration via the run and debug panel (select dropdown at the top and press the play button to the left of it), and test if it works! It should automatically compile using scons and then run it with the debugger hooked.

Levi

sian2005 Thanks, these steps make it easy to get breakpoints working!

I'd add one bit of info though. If you update this launch configuration to run the actual editor (instead of the project directly), then breakpoints will no longer work! If you want breakpoints to work when running your game through the editor, then you'll need to attach the debugger in VSCode to the game process, rather than the editor process it'll be attached to by default.

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