Android symbols

To help you debug your application, Unity can generate a package that contains symbol files for native Unity libraries. Symbol files contain a table that translates active memory addresses into information you can use, like a method name. The translation process is called symbolication. You can upload a symbols package to the Google Play Console to see a human-readable stack trace on the Android Vitals dashboard.

There are two types of symbol files:

• Public: A small file that contains a symbol table. For more information, see Public symbols.
• Debug: Contains everything that a public symbol file contains, and full debugging information that you can use for more in-depth debugging. For more information, see Debugging symbols.

You can generate symbol files for the following libraries:

• libmain: Responsible for initial Unity engine loading logic.
• libunity: Unity’s engine code.
• libil2cpp: Contains C# scripts from the project converted to C++ code.

Unity generates the libmain and libunity symbol files. Gradle generates the libil2cpp symbol file.

Public symbols

A public symbol file contains information that resolves function addresses to human-readable strings. Unity uses the --strip-debug parameter to create public symbols that remove more in-depth debug information. This makes public symbol files and packages smaller than debugging symbol files and packages.

Debugging symbols

A debugging symbol file contains full debugging information and a symbol table. Use it to:

• Resolve stack traces and to debug applications that you have source code available for.
• Attach a native debugger to the application and debug the code.

Unity uses the --only-keep-debug parameter to create debugging symbols. For more information, see –only-keep-debug in the Linux user manual.

Note: If debugging symbols aren’t available, Unity places a public symbol file in your project at build time. For the libmain and libunity libraries, debugging symbols are not available and Unity always generates public symbol files.

Custom symbols

You can instruct Unity to include additional symbol files. This is useful if you use shared libraries and want your local debugger, and Google Play, to resolve the shared library stack traces if the application crashes.

To make Unity include a custom symbols file:

1. In the Project window, select a plug-in that has a .so file extension.
2. In the Inspector, find the Platform settings section.
3. Set CPU to the CPU architecture that the symbols file is compatible with.
4. Set Shared Library Type to Symbol.

Whenever Unity generates a symbols package, it adds the additional symbol files to the symbols package.

If you want to make Unity include a custom symbols file from a C# script, the UnityEditor.Android namespace includes the following APIs to set the CPU and Shared Library Type respectively:

• PluginImporter.SetAndroidCPU
• PluginImporter.SetAndroidSharedLibraryType

Note: The symbols file name must match the name of the shared library that the symbols file is for. For example, if a shared library is called mylibrary.so, the symbols file must also be named mylibrary.so. To avoid file name collisions, the symbols file and the shared library must be in separate directories.

Important: Ensure the symbols file is up to date and compatible with the shared library that contains the executable code. If you don’t, your local debugger and Google Play will fail to resolve stack traces for code in the shared library.

Generating a symbols package

There are two ways to enable symbols package generation for your application:

• In the Build Settings window:
• Open the Build Settings window (menu: File > Build Settings).
• Select the Android platform.
• Set Create symbols.zip to one of the following:
  • Public
  • Debugging
• Use the EditorUserBuildSettings.androidCreateSymbols API.

After you enable symbols package generation, building your project generates a .zip file that contains symbol files for the libmain and libunity library. If you set your scripting backend to IL2CPP, the .zip also contains a symbol file for the libil2cpp library. Unity places this symbols package within the output directory.

If you enable Export Project in the Android Build Settings, Unity doesn’t build the project. Instead, it exports the project for Android Studio, generates symbols for libmain and libunity, and places them within unityLibrary/symbols/<architecture>/ in the output directory. When you build your exported project from Android Studio, Gradle generates the libil2cpp symbol file and places it within the unityLibrary/symbols/<architecture>/ directory alongside the libmain and libunity symbol file.

Using symbols in the Google Play console

After you upload your application to Google Play, you can upload a public symbols package for it. For information on how to do this, see Google’s documentation: Deobfuscate or symbolicate crash stack traces.

Note: Google Play doesn’t symbolicate crashes that your application received before you uploaded the symbols package.