Preserve IL for CoreCLR interpreter fallback on Apple mobile by Copilot · Pull Request #130622 · dotnet/runtime

Copilot · 2026-07-13T13:31:05Z

Apple mobile composite ReadyToRun publishing could strip IL later required by the CoreCLR interpreter when compiled code is rejected or unavailable in a custom load context.

Stripping policy
- Preserve IL for methods with per-method instruction-set support fixups.
- Retain component IL on Apple mobile targets where interpreter fallback remains possible.
Coverage
- Add focused ReadyToRun coverage for opportunistic instruction sets and Apple mobile publishing.
- Remove the temporary project-level IL-stripping opt-outs.

dotnet-policy-service · 2026-07-13T13:53:34Z

Tagging subscribers to this area: @dotnet/runtime-infrastructure
See info in area-owners.md if you want to be subscribed.

Co-authored-by: kotlarmilos <11523312+kotlarmilos@users.noreply.github.com>

kotlarmilos · 2026-07-13T15:18:12Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-07-13T15:18:42Z

Azure Pipelines successfully started running 1 pipeline(s).

jkotas · 2026-07-13T22:05:32Z

Apple mobile composite ReadyToRun publishing could strip IL later required by the CoreCLR interpreter when compiled code is rejected

This sounds like a bug in how we produce the R2R images for use with interpreter. The instruction set should be fixed in this case, and we should never reject the native code. If the actual machine supports more instruction set extensions that the fixed set, we should ignore them.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 19812166-4b05-40cc-9a81-8b80b909e10b

Copilot

Pull request overview

This PR adjusts composite ReadyToRun IL-stripping behavior so IL is retained when it may be needed at runtime (notably for interpreter fallback scenarios), and tightens instruction-set handling on “fixed instruction set” platforms (Apple mobile / browser), with added ReadyToRun test coverage.

Changes:

Removes temporary project-level PublishReadyToRunStripILBodies=false opt-outs from several test projects.
Introduces a shared “fixed instruction set platform” classification and uses it to adjust instruction set support encoding and per-method fixup generation.
Preserves IL for methods that have per-method instruction-set support fixups, and adds/extends ReadyToRun tests to validate stripping/preservation behavior across target configurations.

Show a summary per file

File	Description
src/tests/JIT/Regression/Regression_o_2.csproj	Removes a project-level opt-out from ReadyToRun IL stripping.
src/libraries/System.Reflection.Metadata/tests/System.Reflection.Metadata.Tests.csproj	Removes a project-level opt-out from ReadyToRun IL stripping.
src/libraries/System.Reflection.Metadata/tests/Metadata/Decoding/SignatureDecoderTests.cs	Updates test logic to recognize an additional stripped-IL sentinel pattern.
src/libraries/System.IO.Hashing/tests/System.IO.Hashing.Tests.csproj	Removes a project-level opt-out from ReadyToRun IL stripping.
src/coreclr/tools/Common/TypeSystem/Common/TargetDetails.cs	Adds a helper to classify fixed-instruction-set target OSes.
src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs	Skips unsupported-ISA-based per-method fixup work on fixed-instruction-set platforms; adjusts fixup support construction accordingly.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/ReadyToRunCodegenCompilation.cs	Uses a fixed-instruction-set-aware baseline instruction set support signature; plumbs per-method-fixup method set into component rewriting.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRunCodegenNodeFactory.cs	Collects methods that carry per-method instruction-set support fixups while building the compiled-method definition set.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/CopiedMethodILNode.cs	Preserves IL for methods known to have per-method instruction-set support fixups during strip-IL processing.
src/coreclr/tools/aot/ILCompiler.ReadyToRun.Tests/TestCases/RuntimeAsync/StripILBodies.cs	Adds a runtime-checked-instruction-set probe method used by strip/preserve IL tests.
src/coreclr/tools/aot/ILCompiler.ReadyToRun.Tests/TestCases/R2RTestSuites.cs	Extends strip-IL test coverage and adds an iOS-targeted validation case for fixed-instruction-set behavior.
src/coreclr/tools/aot/crossgen2/Program.cs	Centralizes fixed-instruction-set detection and uses it to disable optimistic ISA defaults and Vector optimism accordingly.

Copilot's findings

Files reviewed: 12/12 changed files
Comments generated: 1

kotlarmilos · 2026-07-14T13:23:58Z

Apple mobile composite ReadyToRun publishing could strip IL later required by the CoreCLR interpreter when compiled code is rejected

This sounds like a bug in how we produce the R2R images for use with interpreter. The instruction set should be fixed in this case, and we should never reject the native code. If the actual machine supports more instruction set extensions that the fixed set, we should ignore them.

Updated the PR to keep IL stripping enabled on Apple and fix the known fallback paths. Crossgen2 now treats Apple mobile and browser as fixed instruction-set targets, so additional runtime ISA support does not reject valid baseline native code. Non-fixed targets still preserve IL for methods with per-method ISA fixups.

Custom AssemblyLoadContext scenarios retain scoped project opt-outs which would require the assembly-level exclusion mentioned in #130620.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 19812166-4b05-40cc-9a81-8b80b909e10b

Copilot

Copilot's findings

Files reviewed: 12/12 changed files
Comments generated: 3

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 12/12 changed files
Comments generated: 1

+        /// <summary>
+        /// Returns <see langword="true"/> for target OSes where the runtime cannot JIT new code, so ISA support is treated as fixed.
+        /// </summary>
+        public static bool IsFixedInstructionSetPlatform(TargetOS operatingSystem) =>
+            operatingSystem is TargetOS.iOS or TargetOS.tvOS
+                or TargetOS.iOSSimulator or TargetOS.tvOSSimulator
+                or TargetOS.MacCatalyst or TargetOS.Browser;


kotlarmilos · 2026-07-14T14:05:22Z

/azp run runtime-extra-platforms

azure-pipelines · 2026-07-14T14:05:35Z

Azure Pipelines: Successfully started running 1 pipeline(s).

Initial plan

eacd9d2

Copilot AI assigned Copilot and kotlarmilos Jul 13, 2026

Copilot AI requested review from Copilot and removed request for Copilot July 13, 2026 13:31

Copilot started work on behalf of kotlarmilos July 13, 2026 13:31 View session

Copilot AI linked an issue Jul 13, 2026 that may be closed by this pull request

[clr-ios] Track IL-stripping issues for CoreCLR on Apple mobile #130620

Open

github-actions Bot added the area-Infrastructure label Jul 13, 2026

github-project-automation Bot added this to Runtime Infra Jul 13, 2026

Preserve IL for CoreCLR interpreter fallback

f5f5cce

Co-authored-by: kotlarmilos <11523312+kotlarmilos@users.noreply.github.com>

Copilot AI requested review from Copilot and removed request for Copilot July 13, 2026 14:07

Complete IL stripping validation

7462331

Co-authored-by: kotlarmilos <11523312+kotlarmilos@users.noreply.github.com>

Copilot AI requested review from Copilot and removed request for Copilot July 13, 2026 14:18

Copilot AI changed the title ~~[WIP] Track IL-stripping issues for CoreCLR on Apple mobile~~ Preserve IL for CoreCLR interpreter fallback on Apple mobile Jul 13, 2026

Copilot finished work on behalf of kotlarmilos July 13, 2026 14:19

Copilot AI requested a review from kotlarmilos July 13, 2026 14:19

BrzVlad reviewed Jul 13, 2026

View reviewed changes

Comment thread src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/ReadyToRunCodegenCompilation.cs Outdated

This was referenced Jul 13, 2026

slow macOS - "##[error]The job running on agent Azure Pipelines 9 ran longer than the maximum time of 60 minutes." dotnet/dnceng#1883

Open

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

Open

jkotas reviewed Jul 13, 2026

View reviewed changes

Comment thread src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/ReadyToRunCodegenCompilation.cs Outdated

Fix fixed ISA handling for stripped R2R images

bbff0da

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 19812166-4b05-40cc-9a81-8b80b909e10b

Copilot AI review requested due to automatic review settings July 14, 2026 12:08

Copilot started reviewing on behalf of kotlarmilos July 14, 2026 12:09 View session

Copilot AI reviewed Jul 14, 2026

View reviewed changes

Comment thread src/libraries/System.Reflection.Metadata/tests/Metadata/Decoding/SignatureDecoderTests.cs

Merge main into IL stripping fixes

7276e8a

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 19812166-4b05-40cc-9a81-8b80b909e10b

Copilot AI review requested due to automatic review settings July 14, 2026 13:29

kotlarmilos temporarily deployed to copilot-pat-pool July 14, 2026 13:29 — with GitHub Actions Inactive

kotlarmilos temporarily deployed to copilot-pat-pool July 14, 2026 13:30 — with GitHub Actions Inactive

Copilot started reviewing on behalf of kotlarmilos July 14, 2026 13:30 View session

Copilot AI reviewed Jul 14, 2026

View reviewed changes

Potential fix for pull request finding

6f8d7a0

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings July 14, 2026 13:49

kotlarmilos temporarily deployed to copilot-pat-pool July 14, 2026 13:49 — with GitHub Actions Inactive

Potential fix for pull request finding

12d0b93

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot started reviewing on behalf of kotlarmilos July 14, 2026 13:50 View session

kotlarmilos temporarily deployed to copilot-pat-pool July 14, 2026 13:51 — with GitHub Actions Inactive

Copilot AI reviewed Jul 14, 2026

View reviewed changes

Uh oh!

Conversation

Copilot AI commented Jul 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

dotnet-policy-service Bot commented Jul 13, 2026

Uh oh!

kotlarmilos commented Jul 13, 2026

Uh oh!

azure-pipelines Bot commented Jul 13, 2026

Uh oh!

Uh oh!

jkotas commented Jul 13, 2026

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Copilot's findings

Uh oh!

Uh oh!

kotlarmilos commented Jul 14, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Copilot's findings

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Copilot's findings

Uh oh!

kotlarmilos commented Jul 14, 2026

Uh oh!

azure-pipelines Bot commented Jul 14, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Copilot AI commented Jul 13, 2026 •

edited

Loading