You can provide additional arguments for the IL2CPPA Unity-developed scripting back-end which you can use as an alternative to Mono when building projects for some platforms. More info
See in Glossary compiler using the PlayerSettings.SetAdditionalIl2CppArgs API or by setting the IL2CPP_ADDITIONAL_ARGS environment variable.
Warning: Passing additional arguments to the IL2CPP compiler is an experimental feature for debugging and optimizing IL2CPP code generation in complex projects. Like diagnostics switches, it’s intended for use by advanced developers in coordination with Unity support staff. Arguments are passed directly to the C++ compiler with no interpretation, which means there is a high risk of breaking builds. Unity reserves the right to change or remove this feature without notice.
The following table displays the arguments you can use to provide additional flags to the IL2CPP compiler:
| Argument | Description |
|---|---|
--compiler-flags="<flags>" |
Passes additional flags to the C++ compiler. Replace <flags> with the desired flags. For example, --compiler-flags=\"COMPILER_FLAG_1 COMPILER_FLAG_2\" passes the compiler flags COMPILER_FLAG_1 and COMPILER_FLAG_2 to the C++ compiler. |
--linker-flags="<flags>" |
Passes additional flags to the linker. Replace <flags> with the desired flags. For example, --linker-flags="\LINKER_FLAG_1 LINKER_FLAG_2\" passes the linker flags LINKER_FLAG_1 and LINKER_FLAG_2 to the linker. |
Multiple arguments must be space separated as follows:
PlayerSettings.SetAdditionalIl2CppArgs("--compiler-flags=\"COMPILER_FLAG_1 COMPILER_FLAG_2\" --linker-flags="\LINKER_FLAG_1 LINKER_FLAG_2\"");
Note: Calling SetAdditionalIl2CppArgs more than once overwrites any flags provided previously. Pass an empty string to this method to remove any previously provided additional arguments.
Valid compiler and linker flags differ by platform, depending on which underlying C++ compiler (msvc or clang) IL2CPP uses on that platform. For a list of valid compiler and linker options, refer to the relevant third-party documentation for msvc compiler, linker options, or clang compiler and linker options.
If your project has additional IL2CPP arguments set, then compiling for more than one platform might not work as expected, especially when cross-compiling for Linux.
To check if any additional IL2CPP arguments are already set, do one of the following:
IL2CPP_ADDITIONAL_ARGS is set.ProjectSettings/ProjectSettings.asset, check if the Editor script has a value called additionalIl2CppArgs.
Important: Additional IL2CPP arguments are globally applied to all platforms, which can cause compilation issues if set for a platform other than the desired platform. Use the IPreprocessBuildWithContext hook to ensure IL2CPP arguments are set only for the platform that requires them.
You can use the IPreprocessBuildWithContext callback to build scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
See in Glossary or the Build dialog to set the additional arguments:
class MyCustomPreprocessBuild: IPreprocessBuildWithContext
{
public int callbackOrder { get { return 0; } }
public void OnPreprocessBuild(BuildCallbackContext ctx)
{
string addlArgs = "";
if (ctx.Report.summary.platform == BuildTarget.StandaloneWindows || ctx.Report.summary.platform == BuildTarget.StandaloneWindows64)
addlArgs = "--compiler-flags=\"d2ssa-cfg-jt\"";
UnityEngine.Debug.Log($"Setting Additional IL2CPP Args = \"{addlArgs}\" for platform {report.summary.platform}");
PlayerSettings.SetAdditionalIl2CppArgs(addlArgs);
}
}