[BUG]: iOS MAUI Builds Consistently Hang when LLVM touching Microsoft.CodeAnalysis.CSharp.Workspaces.dll

[AuriR]

What happened?

See the attached logs. I don't get any exceptions - the build agent simply stops at the Microsoft.CodeAnalysis.CSharp.Workspaces.dll when running the LLVM on it (or so it seems). Then it sits there and times out. From a "detailed" log level:

Mac Studio running M3 and tool version 4.258.1
Machine has 96 GB RAM, running Catalina 15.5, and XCode 16.4
Both .NET 8 and .NET 9 ARM payloads are installed

Disabling LLVM tends to solve, but then the app has trouble launching. Solution builds fine locally on x64 Windows PC. Have not tried Mac from regular command line.

(previous tool execution worked fine)
2025-07-18T20:21:33.3922210Z Started external tool execution #233: /Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/_tool/dotnet/packs/Microsoft.NETCore.App.Runtime.AOT.osx-arm64.Cross.ios-arm64/9.0.7/Sdk/../tools/mono-aot-cross --path=/Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/1/s/src/NameWitheldToProtectInnocent.Stocklink.Maui/obj/Release/net9.0-ios/ios-arm64/linked --aot=mtriple=arm64-ios,data-outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/NameWitheldToProtectInnocent.Stocklink.Maui.aotdata,static,asmonly,dedup-skip,direct-icalls,full,readonly-value=ObjCRuntime.Runtime.Arch=i4/0,nodebug,dwarfdebug,llvm-path=/Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/_tool/dotnet/packs/Microsoft.NETCore.App.Runtime.AOT.osx-arm64.Cross.ios-arm64/9.0.7/Sdk/../tools,outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/NameWitheldToProtectInnocent.Stocklink.Maui.dll.s,llvm-outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/NameWitheldToProtectInnocent.Stocklink.Maui.dll.llvm.o --debug --llvm -O=gsharedvt /Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/1/s/src/NameWitheldToProtectInnocent.Stocklink.Maui/obj/Release/net9.0-ios/ios-arm64/linked/NameWitheldToProtectInnocent.Stocklink.Maui.dll

(enabled diagnostic mode to assist you)
2025-07-18T20:21:36.8590040Z ##[debug]Agent environment resources - Disk: / Available 862018.06 MB out of 948584.16 MB, Memory: Used 52161.00 MB out of 97418.00 MB, CPU: Usage 8.59%
2025-07-18T20:21:42.0097250Z ##[debug]Agent environment resources - Disk: / Available 862018.06 MB out of 948584.16 MB, Memory: Used 52068.00 MB out of 97410.00 MB, CPU: Usage 8.59%
2025-07-18T20:21:47.0737880Z ##[debug]Agent environment resources - Disk: / Available 862018.06 MB out of 948584.16 MB, Memory: Used 52208.00 MB out of 97419.00 MB, CPU: Usage 7.68%

(then it always hangs here)
2025-07-18T20:21:50.8817090Z Started external tool execution #234: /Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/_tool/dotnet/packs/Microsoft.NETCore.App.Runtime.AOT.osx-arm64.Cross.ios-arm64/9.0.7/Sdk/../tools/mono-aot-cross --path=/Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/1/s/src/NameWitheldToProtectInnocent.Stocklink.Maui/obj/Release/net9.0-ios/ios-arm64/linked --aot=mtriple=arm64-ios,data-outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/Microsoft.CodeAnalysis.CSharp.Workspaces.aotdata,static,asmonly,dedup-skip,direct-icalls,full,readonly-value=ObjCRuntime.Runtime.Arch=i4/0,nodebug,dwarfdebug,llvm-path=/Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/_tool/dotnet/packs/Microsoft.NETCore.App.Runtime.AOT.osx-arm64.Cross.ios-arm64/9.0.7/Sdk/../tools,outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/Microsoft.CodeAnalysis.CSharp.Workspaces.dll.s,llvm-outfile=obj/Release/net9.0-ios/ios-arm64/nativelibraries/aot-output/arm64/Microsoft.CodeAnalysis.CSharp.Workspaces.dll.llvm.o --debug --llvm -O=gsharedvt /Users/m3user/buildagents/vsts-agent-osx-arm64-4.258.1/_work/1/s/src/NameWitheldToProtectInnocent.Stocklink.Maui/obj/Release/net9.0-ios/ios-arm64/linked/Microsoft.CodeAnalysis.CSharp.Workspaces.dll

YAML:

• task: DotNetCoreCLI@2
  displayName: 'Build the iOS Binaries'
  timeoutInMinutes: 90
  inputs:
  command: 'publish'
  publishWebProjects: false
  projects: '**/src/NameWitheldToProtectInnocent.Stocklink.Maui/*.csproj'
  arguments: '-f:$(iOSVersion) -c:Release -v:n'
  zipAfterPublish: false
  env:
  DISABLE_BITCODE: 'yes'

Versions

macOS Catalina 15.5, Agent 4.258.1 ARM

Environment type (Please select at least one enviroment where you face this issue)

• Self-Hosted
• Microsoft Hosted
• VMSS Pool
• Container

Azure DevOps Server type

dev.azure.com (formerly visualstudio.com)

Azure DevOps Server Version (if applicable)

No response

Operation system

No response

Version controll system

Git (ADO)

Relevant log output

See above. Since there could be sensitive information, I'd like to share more via a private link :) Thanks!