tvos-arm64 Mono AOT precompilation fails with Invalid IL code for multiple test assemblies

[kotlarmilos]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1362636
Build error leg or test failing: System.Net.NameResolution.Functional.Tests.WorkItemExecution, System.Reflection.Context.Tests.WorkItemExecution, System.Text.Encoding.Extensions.Tests.WorkItemExecution
Pull request: #125441

Affected CI jobs: build_tvos_arm64_Release_AllSubsets_Mono

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "Precompiling failed",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Summary

On tvos-arm64 Mono Release (AOT mode), the Mono AOT compiler fails to precompile test assemblies with "Invalid IL code" errors:

Precompiling failed for aot-instances.dll with exit code 134
Unable to compile method ... due to: 'Invalid IL code in ...: IL_0000: ret'

3 work items affected:

• System.Net.NameResolution.Functional.Tests
• System.Reflection.Context.Tests
• System.Text.Encoding.Extensions.Tests

Note

This issue was filed with the assistance of GitHub Copilot.

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1362636
Error message validated: [Precompiling failed]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 4/2/2026 10:17:08 AM UTC

Report

Build	Repository	Test	Pull Request
1552139	dotnet/runtime	System.Diagnostics.StackTrace.Tests.WorkItemExecution
1552144	dotnet/runtime	System.Runtime.Tests.WorkItemExecution
1551997	dotnet/runtime	System.Globalization.Calendars.Tests.WorkItemExecution
1551570	dotnet/runtime	System.Composition.Runtime.Tests.WorkItemExecution
1551205	dotnet/runtime	System.Formats.Asn1.Tests.WorkItemExecution
1551216	dotnet/runtime	System.Runtime.Tests.WorkItemExecution	#132255
1550103	dotnet/runtime	System.IO.Packaging.Tests.WorkItemExecution
1550470	dotnet/runtime	System.Runtime.Tests.WorkItemExecution	#132160
1549807	dotnet/runtime	System.Globalization.CalendarsWithConfigSwitch.Tests.WorkItemExecution
1548190	dotnet/runtime	System.IO.Compression.Brotli.Tests.WorkItemExecution
1546722	dotnet/runtime	System.Composition.Runtime.Tests.WorkItemExecution
1546713	dotnet/runtime	System.Diagnostics.DiagnosticSource.Switches.Tests.WorkItemExecution
1546377	dotnet/runtime	Microsoft.Extensions.Configuration.Ini.Tests.WorkItemExecution
1542613	dotnet/runtime	System.Composition.Hosting.Tests.WorkItemExecution
1541064	dotnet/runtime	Microsoft.Extensions.Primitives.Tests.WorkItemExecution	#131209

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	6	15

[dotnet-policy-service]

Tagging subscribers to 'os-tvos': @vitek-karas, @kotlarmilos, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[BrzVlad]

@kotlarmilos Any idea about this ? I seem to remember you fixed something similar at some point, with the issue being that we were passing the wrong processed assemblies to the compiler, some issue on the infrastructure side.

Looking at some logs seems like this might match on unrelated issues. Ex:

/tmp/helix/working/9699087B/p/build/apple/AppleBuild.targets(260,5): error : Precompiling failed for /tmp/helix/working/9699087B/w/B61009D4/e/publish/JsonSchema.Net.dll with exit code 1. [/private/tmp/helix/working/9699087B/w/B61009D4/e/publish/ProxyProjecUnhandled exception: Unhandled exception: No space left on device

[kotlarmilos]

This happens on Helix retries. I think the ILLinker runs on the first attempt, and if the job fails, it tries trimming again on the same payload, which has already been trimmed. Although the error message is too generic