Share `ObjectiveCMarshal` reference-tracking logic between CoreCLR and NativeAOT by Copilot · Pull Request #128961 · dotnet/runtime

Copilot · 2026-06-03T20:13:24Z

ObjectiveCMarshal had divergent CoreCLR and NativeAOT implementations for tagged reference-tracking memory. This change moves CoreCLR to the same ConditionalWeakTable<object, ObjcTrackingInformation> model used by NativeAOT and updates diagnostics contracts accordingly.

Description
- CoreCLR managed ObjectiveCMarshal now owns tagged memory
  - Added CoreCLR-side s_objects CWT and ObjcTrackingInformation lifecycle logic in ObjectiveCMarshal.CoreCLR.cs.
  - Unified CreateReferenceTrackingHandle / GetOrCreateReferenceTrackingMemory flow to use managed CWT-backed memory for both runtimes.
  - Initialize now passes the CWT instance to native for unmanaged lookup during GC callbacks.
- CoreCLR native Objective-C interop path no longer uses syncblk tagged storage
  - Removed Objective-C-specific syncblk tagged-memory allocation/retrieval path from interoplibinterface_objc.cpp.
  - Replaced with unmanaged CWT lookup (ConditionalWeakTableObject::TryGetValue) to resolve tagged memory from managed state.
  - Split QCall responsibilities so native only allocates the ref-counted handle (ObjCMarshal_AllocateReferenceTrackingHandle).
- Unmanaged CWT accessor usage enabled in runtime path
  - Exposed ConditionalWeakTable native lookup helpers for this suspended-runtime callback scenario and clarified constraints in comments.
- cDAC ObjectiveCMarshal contract folded into version c1
  - Replaced ObjectiveCMarshal_1 implementation to read tagged memory via ObjectiveCMarshal.s_objects and CWT entries.

// CoreCLR native callback path now resolves tagged memory from managed CWT state.
CONDITIONAL_WEAK_TABLE_REF trackingTable = (CONDITIONAL_WEAK_TABLE_REF)ObjectFromHandle(g_ObjectiveCTrackingInfoTable);
OBJECTREF trackingInfoObj = NULL;
if (!trackingTable->TryGetValue(object, &trackingInfoObj))
    return false;

OBJC_TRACKING_INFO_REF trackingInfo = (OBJC_TRACKING_INFO_REF)trackingInfoObj;
void* taggedLocal = (void*)trackingInfo->_memory;

dotnet-policy-service · 2026-06-03T21:25:31Z

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AaronRobinsonMSFT · 2026-06-04T20:42:31Z

@copilot Please fold the cDAC changes into version 1. There is no backwards compat concerns here. We can change version 1 without issue.

Copilot · 2026-06-04T20:51:22Z

@copilot Please fold the cDAC changes into version 1. There is no backwards compat concerns here. We can change version 1 without issue.

Addressed in 0edf747. I folded the ObjectiveCMarshal cDAC changes into version c1, removed the c2 registration/implementation, and updated the CoreCLR data descriptor contract entry back to c1.

Co-authored-by: AaronRobinsonMSFT <30635565+AaronRobinsonMSFT@users.noreply.github.com>

- Use sizeof(TADDR) instead of sizeof(void*) in DAC for target size - Mark s_objects as readonly; use local copy for ObjectHandleOnStack - Guard gcinterface.dac.h include with DACCESS_COMPILE Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 26/26 changed files
Comments generated: 2

Add tests exercising the ConditionalWeakTable-based GetTaggedMemory path: - ObjectNotInTable: CWT exists but object not tracked - NullMemory: object tracked but memory pointer is null - HasMemory: object tracked with valid tagged memory Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bjC stubs - Use m_Array directly instead of GetGCSafeDataPtr() per review feedback - Update Mono ObjectiveCMarshal stubs to match shared API changes Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…al methods Extract the unsafe MethodTable check into a partial method on each runtime (CoreCLR, NativeAOT, Mono stub) so the shared ObjectiveCMarshal.cs no longer requires an unsafe context for the validation. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 27/27 changed files
Comments generated: 4

In DAC mode, m_Array yields a host address, but PTR_KIND requires a target address. GetDataPtr() computes the correct target address via dac_cast<PTR_BYTE>(this) + offset. This was broken by PR #128961 which changed from GetDataPtr() to m_Array, breaking debugger inspection of exception stack traces, ConditionalWeakTable lookups, and stack frame helper arrays in DAC mode. --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fixes failing OSX cDac test. I think this is a regression from #128961. This pull request updates the handling of pointer types in managed code to better align with how .NET expresses raw pointers. The main change is to allow fields typed as `IntPtr`/`UIntPtr` (reported as `"nint"`/`"nuint"`) to be treated as pointers by the contract reader, improving compatibility and correctness when reading pointer-sized fields. Improvements to pointer type handling: * Updated `AssertPointerType` in `TargetFieldExtensions.cs` to accept `"nint"` and `"nuint"` as valid pointer type names, in addition to `"pointer"`, enabling proper handling of managed fields typed as `IntPtr`/`UIntPtr`. Test and contract descriptor alignment: * Modified the test contract for the `_memory` field in `ObjectiveCMarshalTests.cs` to explicitly set its type as `"nint"`, ensuring that the pointer read path is validated against the real managed contract descriptor. --------- Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot AI self-assigned this Jun 3, 2026

Copilot AI review requested due to automatic review settings June 3, 2026 20:13

Copilot AI assigned AaronRobinsonMSFT Jun 3, 2026

Copilot AI removed the request for review from Copilot June 3, 2026 20:13

github-project-automation Bot added this to AppModel Jun 3, 2026

Copilot started work on behalf of AaronRobinsonMSFT June 3, 2026 20:13 View session

Copilot AI linked an issue Jun 3, 2026 that may be closed by this pull request

Share ObjectiveCMarshal API implementation between CoreCLR and NativeAOT #128925

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Copilot AI requested review from Copilot and removed request for Copilot June 3, 2026 20:38

Copilot AI changed the title ~~[WIP] Share ObjectiveCMarshal API implementation between CoreCLR and NativeAOT~~ Share ObjectiveCMarshal reference-tracking storage between CoreCLR and NativeAOT Jun 3, 2026

Copilot finished work on behalf of AaronRobinsonMSFT June 3, 2026 20:45

Copilot AI requested a review from AaronRobinsonMSFT June 3, 2026 20:45

github-actions Bot added the area-Diagnostics-coreclr label Jun 3, 2026

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/CoreCLRContracts.cs Outdated

noahfalk reviewed Jun 4, 2026

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Comment thread ...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ObjectiveCMarshal_2.cs Outdated

Copilot started work on behalf of AaronRobinsonMSFT June 4, 2026 20:42 View session

Copilot AI requested review from Copilot and removed request for Copilot June 4, 2026 20:50

Copilot AI changed the title ~~Share ObjectiveCMarshal reference-tracking storage between CoreCLR and NativeAOT~~ Share ObjectiveCMarshal reference-tracking storage between CoreCLR and NativeAOT (cDAC contract stays at v1) Jun 4, 2026

Copilot finished work on behalf of AaronRobinsonMSFT June 4, 2026 20:52

Copilot AI review requested due to automatic review settings June 8, 2026 18:13

Copilot started reviewing on behalf of AaronRobinsonMSFT June 8, 2026 18:14 View session

Copilot AI and others added 3 commits June 8, 2026 11:16

Initial plan

d9dfe47

Share ObjectiveCMarshal tracking implementation on CoreCLR

c0c5981

Co-authored-by: AaronRobinsonMSFT <30635565+AaronRobinsonMSFT@users.noreply.github.com>

Address review feedback on ObjectiveCMarshal sharing

a2f8c37

Co-authored-by: AaronRobinsonMSFT <30635565+AaronRobinsonMSFT@users.noreply.github.com>

Copilot AI review requested due to automatic review settings June 8, 2026 18:52

Copilot started reviewing on behalf of AaronRobinsonMSFT June 8, 2026 18:52 View session

Copilot AI reviewed Jun 8, 2026

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Comment thread ...es/System.Private.CoreLib/src/System/Runtime/InteropServices/ObjectiveC/ObjectiveCMarshal.cs

Comment thread ...ged/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ObjectiveCMarshal_1.cs

jkotas marked this pull request as ready for review June 8, 2026 19:08

jkotas requested a review from MichalStrehovsky as a code owner June 8, 2026 19:08

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Comment thread src/coreclr/vm/object.h

This was referenced Jun 8, 2026

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

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

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AaronRobinsonMSFT and others added 2 commits June 8, 2026 18:43

AaronRobinsonMSFT requested review from steveisok and vitek-karas as code owners June 9, 2026 01:54

jkotas approved these changes Jun 9, 2026

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Copilot AI review requested due to automatic review settings June 9, 2026 02:50

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AaronRobinsonMSFT approved these changes Jun 9, 2026

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Copilot AI reviewed Jun 9, 2026

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Comment thread src/coreclr/vm/object.h

Comment thread src/native/managed/cdac/tests/UnitTests/ObjectiveCMarshalTests.cs

Comment thread src/native/managed/cdac/tests/UnitTests/ObjectiveCMarshalTests.cs

Comment thread src/native/managed/cdac/tests/UnitTests/ObjectiveCMarshalTests.cs

This was referenced Jun 9, 2026

TestNativeDigits fails for ur-IN on Apple platforms (xunit v3 exposed previously non-running test) #125933

Open

CI build failure: error CS8032: An instance of analyzer Microsoft.NetCore.CSharp.Analyzers.... cannot be created #129031

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AaronRobinsonMSFT merged commit 4b6b5d0 into main Jun 9, 2026
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AaronRobinsonMSFT deleted the copilot/share-objectivecmarshal-api branch June 9, 2026 14:29

github-project-automation Bot moved this to Done in AppModel Jun 9, 2026

dotnet-maestro Bot mentioned this pull request Jun 10, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#7160

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tommcdon mentioned this pull request Jun 11, 2026

Fix Array::GetDirectPointerToNonObjectElements DAC regression #129271

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dotnet-maestro Bot mentioned this pull request Jun 11, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#7196

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leculver mentioned this pull request Jun 16, 2026

[cDac] Fix failing cDac test on OSX #129462

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Share `ObjectiveCMarshal` reference-tracking logic between CoreCLR and NativeAOT#128961

Share `ObjectiveCMarshal` reference-tracking logic between CoreCLR and NativeAOT#128961
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