Unreal Engine Clangd Utils

An extension for Visual Studio Code designed to configure Unreal Engine C++ projects (including UE 5.7 and 5.8) to work seamlessly with clangd IntelliSense.

Provides fast, accurate, and responsive code completion, navigation, and diagnostics for Unreal Engine C++ code, eliminating the common false-positive "red squiggles" and high CPU usage issues associated with the default Microsoft C++ IntelliSense engine.

Prerequisites

Before using this extension, please ensure your system meets the following requirements:

1. Install clangd Toolchain:
   • You need the clangd language server binary on your machine.
   • You can download the LLVM/clangd toolchain from LLVM Releases or let VS Code install it automatically.
2. Install VS Code Extensions:
   • clangd VS Code Extension (Required: this runs the language server client).
   • C/C++ Extension by Microsoft (Recommended: needed for launching/debugging your game targets, though we disable its IntelliSense engine to avoid conflicts).
3. Compile the Project At Least Once:
   • Unreal Engine relies heavily on reflection and code generation (creating *.generated.h files).
   • You must compile your project at least once via Unreal Editor or VS Code build tasks before generating the clang database. If you don't compile, clangd will report errors about missing generated headers.

Key Features

• Automated Clangd Setup: Automatically creates a custom project-specific .clangd file with optimized compiler arguments, disabled template parsing warnings, and specific diagnostic suppressions for Unreal Engine's macro systems (UCLASS, GENERATED_BODY, etc.).
• Automatic Compile Commands Generation: Locates the UnrealBuildTool executable (by scanning tasks, the registry, or standard installation paths) and runs it with -mode=GenerateClangDatabase to build compile_commands.json.
• Database Relocation: Automatically moves/copies the generated compile_commands.json database from the Engine root folder to your project root where the clangd language server can find it.
• Conflict Prevention: Disables Microsoft C/C++ extension's IntelliSense workspace engine (C_Cpp.intelliSenseEngine = disabled) to prevent duplicate diagnostics, lag, and resource conflicts.
• One-Click UI Controls:
  • Status Bar Button: Displays a Generate Clang Database shortcut button at the bottom of the window.
  • Editor Title Button: Shows a database sync icon in the top-right toolbar when editing C++ or .uproject files for quick regeneration.
• Auto-Run on Startup: Prompts you to run the initial setup automatically if your project is missing a .clangd file or compile_commands.json upon opening.

How to Use

1. First-time Setup:
   • Open your Unreal Engine C++ project directory in VS Code.
   • If it's a fresh setup, you will see a notification prompting you to configure the project. Click Setup Now.
   • Alternatively, open the Command Palette (Ctrl+Shift+P) and select Unreal Utils: Setup Project for Clangd.
2. Updating the Database:
   • Whenever you add new C++ files, rename modules, or add new plugin dependencies, the compiler paths change.
   • Simply click the Generate Clang Database button on the bottom status bar, or click the Sync Database icon in the editor toolbar (top-right of C++ files) to regenerate and copy compile_commands.json.

Troubleshooting

Issue: Missing *.generated.h files

• Cause: The project hasn't been built yet, or UBT generated the database without building files.
• Solution: Build your project inside Unreal Editor (e.g. click "Live Coding" or Compile) or run a standard build task in VS Code. Once built, restart the clangd server via the Command Palette (clangd: Restart language server).

Issue: Extension says "Could not locate UnrealBuildTool"

• Cause: Your project doesn't have generated VS Code workspace files, or the Engine is in a non-standard location not indexed by the registry.
• Solution:
  1. Open Unreal Editor and select Tools -> Generate Visual Studio Code Project.
  2. Open VS Code Settings (Ctrl+,), search for Unreal Build Tool Path, and manually paste the absolute path to your UnrealBuildTool.exe.

Issue: Duplicate Diagnostics or Slow Editing Performance

• Cause: Microsoft's C/C++ extension IntelliSense is still running.
• Solution: Ensure your workspace settings file (.vscode/settings.json) contains "C_Cpp.intelliSenseEngine": "disabled". This extension attempts to set this automatically during initial setup.

Extension Settings

This extension contributes the following settings:

• unreal-utils.unrealBuildToolPath: Custom path to the UnrealBuildTool executable. If empty, the extension will auto-resolve it from .vscode/tasks.json or registry entries.
• unreal-utils.targetName: Custom project target name (e.g. MyGameEditor). If left empty, it auto-detects based on the .Target.cs files in your Source/ folder.
• unreal-utils.buildConfiguration: The build configuration to use when generating compile commands (defaults to Development).
• unreal-utils.buildPlatform: The target platform (defaults to Win64).
• unreal-utils.autoRunOnStartup: Toggles whether the extension prompts you to run setup if configurations are missing on startup (default: true).
• unreal-utils.useNoExecCodeGenActions: Appends the -NoExecCodeGenActions flag to the UBT command to significantly speed up database generation (default: true).

License

MIT License. Copyright (c) 2026 Siddartha Gonnabattula.