Unity IL2CPP构建报错：CIL Linker致命错误与System文件夹冲突求助

问题详情 #

使用Unity 2021.2.11f1版本进行IL2CPP构建时失败，Mono构建可正常完成。报错核心为Unity CIL链接器处理System.Windows.Forms.dll中的System.Windows.Forms.XplatUIX11.SetDisplay(IntPtr)方法时，无法解析程序集Mono.Posix, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null，最终导致ManagedStripped构建环节失败。

完整报错堆栈：

Building Library\Bee\artifacts\WinPlayerBuildProgram\ManagedStripped failed with output:
C:\Programms\Unity\Editors\2021.2.11f1\Editor\Data\il2cpp\build\deploy\UnityLinker.exe @Library\Bee\artifacts\rsp\16461770786374037127.rsp
Fatal error in Unity CIL Linker
Mono.Linker.LinkerFatalErrorException: ILLink: error IL1005: System.Windows.Forms.XplatUIX11.SetDisplay(IntPtr): Error processing method 'System.Windows.Forms.XplatUIX11.SetDisplay(IntPtr)' in assembly 'System.Windows.Forms.dll'
 ---> Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: 'Mono.Posix, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null'
   at Unity.IL2CPP.Common.MissingMethodStubber.GetTypeModule(TypeReference type, IEnumerable`1 assemblies)
   at Unity.Linker.Steps.AddUnresolvedStubsStep.MarkAssemblyOfType(UnityLinkContext context, TypeReference type)
   at Unity.Linker.Steps.Marking.UnresolvedStubMarking.HandleUnresolvedType(TypeReference reference)
   at Unity.Linker.Steps.UnityMarkStep.HandleUnresolvedType(TypeReference reference)
   at Mono.Linker.Steps.MarkStep.MarkType(TypeReference reference, DependencyInfo reason, IMemberDefinition sourceLocationMember)
   at Mono.Linker.Steps.MarkStep.MarkMethodBody(MethodBody body)
   at Unity.Linker.Steps.UnityMarkStep.MarkMethodBody(MethodBody body)
   at Mono.Linker.Steps.MarkStep.ProcessMethod(MethodDefinition method, DependencyInfo& reason)
   at Unity.Linker.Steps.UnityMarkStep.ProcessMethod(MethodDefinition method, DependencyInfo& reason)
   at Mono.Linker.Steps.MarkStep.ProcessQueue()
   --- End of inner exception stack trace ---
   at Mono.Linker.Steps.MarkStep.ProcessQueue()
   at Mono.Linker.Steps.MarkStep.ProcessPrimaryQueue()
   at Mono.Linker.Steps.MarkStep.Process()
   at Mono.Linker.Steps.MarkStep.Process(LinkContext context)
   at Unity.Linker.Steps.UnityMarkStep.Process(LinkContext context)
   at Unity.Linker.UnityPipeline.ProcessStep(LinkContext context, IStep step)
   at Mono.Linker.Pipeline.Process(LinkContext context)
   at Unity.Linker.UnityDriver.UnityRun(Boolean noProfilerAllowed, ILogger customLogger)
   at Unity.Linker.UnityDriver.RunDriverWithoutErrorHandling(ILogger customLogger, Boolean noProfilerAllowed)
   at Unity.Linker.UnityDriver.RunDriver()
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

解决方案 #

• 移除无用的System.Windows.Forms引用：如果项目并未使用Windows Forms功能，直接删除Assets目录下的System.Windows.Forms.dll文件，或在Player Settings中检查是否意外添加了该程序集的引用，取消关联即可。
• 手动添加Mono.Posix程序集：获取与Unity 2021.2兼容的Mono.Posix.dll（版本2.0.0.0），将其放入项目的Plugins文件夹，并在Inspector面板中设置正确的平台兼容选项（勾选Windows平台，其他平台排除）。
• 调整链接器剥离策略：
  1. 打开Player Settings，进入Other Settings -> Configuration，将Managed Stripping Level从High改为Medium或Low，降低链接器的代码剥离强度。
  2. 或在Assets根目录创建link.xml文件，强制链接器保留相关程序集：

     <linker>
       <assembly fullname="System.Windows.Forms" preserve="all"/>
       <assembly fullname="Mono.Posix" preserve="all"/>
     </linker>
     

• 清理缓存并重建：删除项目根目录的Library文件夹，等待Unity重新生成项目缓存后，再次尝试IL2CPP构建。
• 升级Unity版本：Unity 2021.2.11f1存在部分IL2CPP构建的已知问题，可升级至同系列的补丁版本（如2021.2.22f1），或降级到更稳定的版本（如2020.3 LTS）。

内容的提问来源于stack exchange，提问作者Олександр Пономаренко