Unity集成Firebase后Xcode归档出现arm64符号未定义错误求助

环境信息 #

• Unity版本：2020.3.36f1
• 集成Firebase模块：认证（Auth）、分析（Analytics）、数据库（Realtime Database）
• Xcode版本：13.4.1

问题现象 #

Unity端构建完全正常，无任何报错，但将Xcode项目归档时出现链接错误，具体日志如下：

ld: warning: arm64 function not 4-byte aligned: _unwind_tester from  /Users/michael/Desktop/Reserve1/Libraries/libiPhone-lib.a(unwind_test_arm64.o)
Undefined symbols for architecture arm64:

"_OBJC_CLASS_$_FIRApp", referenced from:
  objc-class-ref in libFirebaseCppApp.a(app_ios.mm.o)
"_OBJC_CLASS_$_FIRTransactionResult", referenced from:
  objc-class-ref in libFirebaseCppDatabase.a(database_reference_ios.mm.o)
"_OBJC_CLASS_$_FIRTransactionResult", referenced from:
  objc-class-ref in libFirebaseCppDatabase.a(database_reference_ios.mm.o)
"_OBJC_CLASS_$_FIRDatabase", referenced from:
  objc-class-ref in libFirebaseCppDatabase.a(database_ios.mm.o)
"_OBJC_CLASS_$_FIRGameCenterAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRGoogleAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRPhoneAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRPhoneAuthCredential", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(user_ios.mm.o)
"_OBJC_CLASS_$_FIROptions", referenced from:
  objc-class-ref in libFirebaseCppApp.a(app_ios.mm.o)
"_OBJC_CLASS_$_FIROAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
 "_OBJC_CLASS_$_FIRConfiguration", referenced from:
  objc-class-ref in libFirebaseCppApp.a(app_ios.mm.o)
"_OBJC_CLASS_$_FIRFacebookAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRDatabaseReference", referenced from:
  objc-class-ref in libFirebaseCppDatabase.a(database_reference_ios.mm.o)
"_OBJC_CLASS_$_FIREmailAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRGitHubAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRTwitterAuthProvider", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(credential_ios.mm.o)
"_OBJC_CLASS_$_FIRAuth", referenced from:
  objc-class-ref in libFirebaseCppAuth.a(auth_ios.mm.o)
 "_FIRAuthErrorUserInfoUpdatedCredentialKey", referenced from:
  firebase::auth::SignInResultCallback(FIRAuthDataResult*, NSError*, firebase::SafeFutureHandle<firebase::auth::SignInResult>, firebase::auth::AuthData*) in libFirebaseCppAuth.a(auth_ios.mm.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

已尝试的解决方案 #

• 卸载并重新安装CocoaPods
• 修改iOS Resolver的各项设置
• 在Unity和Xcode中重新安装Firebase SDK
• 多次编辑Podfile尝试不同配置
• 遵循网络上相关教程的操作步骤

解决方案建议 #

1. 重新安装CocoaPods依赖 #

打开Xcode项目所在目录，执行以下命令彻底重置依赖：

pod deintegrate
pod clean
pod install --repo-update

完成后务必打开项目对应的.xcworkspace文件（注意不是.xcodeproj）进行归档操作。

2. 验证Firebase SDK版本兼容性 #

确保使用的Firebase SDK版本与Unity 2020.3.36f1完全匹配。Unity 2020.x版本建议搭配Firebase SDK 9.x或10.x系列，避免使用过高版本导致底层链接不兼容。

3. 调整Xcode架构与链接设置 #

• 进入Xcode项目的Build Settings
• 将Architectures设置为Standard Architectures (arm64)
• 确保Release模式下Build Active Architecture Only设置为NO
• 检查Other Linker Flags是否包含-ObjC（Firebase依赖该标志加载Objective-C类）

4. 修正Unity的iOS Resolver配置 #

• 在Unity中打开Assets > External Dependency Manager > iOS Resolver > Settings
• 勾选Auto-Update Pods和Use CocoaPods选项
• 取消勾选Disable Pods Deployment Target，保证Pod部署目标与项目一致
• 重新构建Xcode项目，让Resolver自动处理依赖关联

5. 手动引入Firebase iOS框架 #

如果CocoaPods仍未正确引入框架，可手动下载对应版本的Firebase iOS SDK，将以下框架拖入Xcode项目的Frameworks, Libraries, and Embedded Content中，并设置为Embed & Sign：

• FirebaseCore.framework
• FirebaseAuth.framework
• FirebaseDatabase.framework
• FirebaseAnalytics.framework

6. 清理缓存后重新构建 #

• 在Unity中执行Assets > Clear Cache
• 删除Xcode的DerivedData目录（路径可通过Xcode > Preferences > Locations查看）
• 重新构建Unity项目并归档Xcode工程

内容的提问来源于stack exchange，提问作者Michael Bailey