Adding GetObjectComWrappers cDAC API by rcj1 · Pull Request #125846 · dotnet/runtime

rcj1 · 2026-03-20T17:02:52Z

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dotnet-policy-service · 2026-03-20T17:04:14Z

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Copilot

Pull request overview

Adds cDAC surface area needed to query ComWrappers state for a managed object (RCW + MOWs) by introducing a ConditionalWeakTable contract and supporting runtime/type-system plumbing, plus dump-based integration coverage.

Changes:

Extend cDAC object/syncblock modeling to read object header sync-block state and expose TryGetHashCode.
Add ConditionalWeakTable contract (incl. GC dependent-handle “extra info” access) and implement ComWrappers APIs to retrieve MOWs and RCWs for an object.
Add dump-test debuggee + integration tests, and wire the new support into legacy SOS DAC interop (GetObjectComWrappersData).

Reviewed changes

Copilot reviewed 51 out of 51 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/native/managed/cdac/tests/MockDescriptors/MockDescriptors.cs	Adds mock `ObjectHeader` type and `SyncBlock.HashCode` field for unit-test targets.
src/native/managed/cdac/tests/MockDescriptors/MockDescriptors.Object.cs	Updates mock globals/types to use `ObjectHeader` sizing and adds sync-block hash mask global.
src/native/managed/cdac/tests/MockDescriptors/MockDescriptors.GC.cs	Adds `HandleSegmentSize` global to mock GC heap builders for new handle-extra-info logic.
src/native/managed/cdac/tests/DumpTests/README.md	Documents new ComWrappers dump-test scenario and mapping.
src/native/managed/cdac/tests/DumpTests/Debuggees/ComWrappers/Program.cs	New debuggee that creates one MOW + one RCW via `ComWrappers` then crashes for dump capture.
src/native/managed/cdac/tests/DumpTests/Debuggees/ComWrappers/ComWrappers.csproj	Declares debuggee dump type (`Full`).
src/native/managed/cdac/tests/DumpTests/ComWrappersDumpTests.cs	New dump-based integration tests for `GetMOWs` and `GetComWrappersRCWForObject`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader/CachingContractRegistry.cs	Registers the new `IConditionalWeakTable` factory.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs	Implements `ISOSDacInterface10.GetObjectComWrappersData` using new contracts (and debug-validates against legacy impl in DEBUG).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ISOSDacInterface.cs	Updates `GetObjectComWrappersData` signature to array-based marshalling.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/SyncBlock.cs	Adds `HashCode` field readout from `SyncBlock`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ObjectHeader.cs	New data model to read `SyncBlockValue` from object header.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ManagedObjectWrapperLayout.cs	Expands MOW layout reads with flags, user-defined entries, dispatch section.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ManagedObjectWrapperHolderObject.cs	Adds `Wrapper` pointer field for holder object.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/InternalComInterfaceDispatch.cs	New data model for dispatch blocks used to compute COM identity pointers.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ConditionalWeakTableObject.cs	New data model for the managed CWT object.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ConditionalWeakTableEntry.cs	New data model for CWT entries (hash/next/dep-handle).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ConditionalWeakTableContainerObject.cs	New data model for the CWT container (buckets/entries arrays).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ComInterfaceEntry.cs	New data model for reading GUID IID entries in user-defined COM interface table.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/Array.cs	Exposes `DataPointer` for array element base address.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/RuntimeTypeSystem_1.cs	Adds FieldDesc RVA flag + static-address resolution API (incl. dynamic/big RVA handling).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/Object_1.cs	Uses `ObjectHeader` type info instead of `ObjectHeaderSize` global; adds `TryGetHashCode`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ObjectFactory.cs	Plumbs sync-block bitmasks into `Object_1`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/Loader_1.cs	Adds `GetFieldAddressFromRva` and refactors RVA resolution helper.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs	Adds dependent-handle “extra info” lookup (`GetHandleExtraInfo`).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GCFactory.cs	Plumbs `HandleSegmentSize` into `GC_1`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ConditionalWeakTable_1.cs	New contract implementation to look up CWT value by key identity using dep-handles.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ConditionalWeakTableFactory.cs	New factory for `IConditionalWeakTable`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ComWrappers_1.cs	Implements `GetMOWs`, `GetIdentityForMOW`, and `GetComWrappersRCWForObject` using RTS + CWT.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Constants.cs	Removes `ObjectHeaderSize`; adds globals for hash-code mask, dynamic RVA, handle segment size.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/DataType.cs	Adds new data types (ObjectHeader, ComWrappers-related, CWT-related).
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IRuntimeTypeSystem.cs	Adds `GetFieldDescStaticAddress` API to abstractions.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IObject.cs	Adds `TryGetHashCode` API.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ILoader.cs	Adds `GetFieldAddressFromRva` API.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IGC.cs	Adds `GetHandleExtraInfo` API.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IConditionalWeakTable.cs	Introduces `IConditionalWeakTable` contract abstraction.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IComWrappers.cs	Extends contract surface with MOW/RCW lookup and identity retrieval APIs.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/ContractRegistry.cs	Adds `ConditionalWeakTable` accessor to registry.
src/coreclr/vm/syncblk.h	Adds `SyncBlock.m_dwHashCode` field to cDAC layout.
src/coreclr/vm/interoplibinterface_comwrappers.h	Adds `ManagedObjectWrapperHolderObject::_wrapper` field to cDAC layout.
src/coreclr/vm/datadescriptor/datadescriptor.inc	Adds new types/globals/contracts for ObjectHeader, CWT, ComWrappers dispatch data; removes `ObjectHeaderSize` global.
src/coreclr/vm/datadescriptor/datadescriptor.h	Includes `conditionalweaktable.h` for new cDAC data exposure.
src/coreclr/vm/conditionalweaktable.h	Exposes cDAC layout metadata for CWT container/object and entry details.
src/coreclr/interop/inc/interoplibabi.h	Adds cDAC offsets for new ComWrappers ABI structs/fields.
src/coreclr/interop/inc/interoplib.h	Annotates `CallerDefinedIUnknown` constant as contract-dependent.
src/coreclr/gc/datadescriptor/datadescriptor.inc	Adds `HandleSegmentSize` global for handle-table segment computations.
docs/design/datacontracts/Object.md	Documents `TryGetHashCode` and required descriptors/globals.
docs/design/datacontracts/Loader.md	Documents `GetFieldAddressFromRva` API and RVA helper behavior.
docs/design/datacontracts/GC.md	Documents `GetHandleExtraInfo` API and required globals.
docs/design/datacontracts/ConditionalWeakTable.md	New contract design doc for CWT lookup via dependent handles.
docs/design/datacontracts/ComWrappers.md	Documents new ComWrappers contract APIs and descriptor dependencies.

jkoritzinsky

Generally, looks good! Just a few pieces of feedback.

Removed comment about cDAC dependencies in ConditionalWeakTable_1.

Copilot

Pull request overview

Copilot reviewed 50 out of 50 changed files in this pull request and generated 4 comments.

noahfalk

👍

Copilot

Pull request overview

Copilot reviewed 50 out of 50 changed files in this pull request and generated 6 comments.

Copilot

Pull request overview

Copilot reviewed 50 out of 50 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

src/coreclr/gc/datadescriptor/datadescriptor.inc:128

GC contract versioning: HandleSegmentSize is a new required global for the managed GC contract implementation (GetHandleExtraInfo) but the GC contract is still advertised as version 1 below. If older descriptors are expected to work with newer readers, this should be version-bumped (or the reader should treat HandleSegmentSize as optional and fall back).

CDAC_GLOBAL(HandleSegmentSize, /*uint32*/, HANDLE_SEGMENT_SIZE)
CDAC_GLOBAL(HandleBlocksPerSegment, /*uint32*/, HANDLE_BLOCKS_PER_SEGMENT)
CDAC_GLOBAL(HandleMaxInternalTypes, /*uint32*/, HANDLE_MAX_INTERNAL_TYPES)
CDAC_GLOBAL(HandlesPerBlock, /*uint32*/, HANDLE_HANDLES_PER_BLOCK)
CDAC_GLOBAL(BlockInvalid, /*uint8*/, BLOCK_INVALID)

Copilot

Pull request overview

Copilot reviewed 50 out of 50 changed files in this pull request and generated no new comments.

adding GetObjectComWrappers cDAC API

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rcj1 requested review from barosiak, Copilot, jkoritzinsky, max-charlamb and noahfalk March 20, 2026 17:02

github-actions Bot added the area-Diagnostics-coreclr label Mar 20, 2026

dotnet-policy-service Bot assigned rcj1 Mar 20, 2026

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Comment thread src/coreclr/vm/conditionalweaktable.h

Comment thread ...e/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ComWrappers_1.cs Outdated

Comment thread ...e/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ComWrappers_1.cs

max-charlamb reviewed Mar 20, 2026

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Comment thread docs/design/datacontracts/Object.md Outdated

rcj1 added 2 commits March 20, 2026 16:21

code review

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Remove unnecessary newline in conditionalweaktable.h

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Copilot started reviewing on behalf of rcj1 March 20, 2026 23:24 View session

Remove cDAC dependency comment from ConditionalWeakTable_1

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Removed comment about cDAC dependencies in ConditionalWeakTable_1.

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noahfalk approved these changes Mar 21, 2026

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Comment thread .../cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ConditionalWeakTable_1.cs Outdated

code review

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build-analysis Bot mentioned this pull request Mar 21, 2026

[wasm] OpenQA.Selenium.WebDriverTimeoutException: timeout: Timed out receiving message from renderer #117486

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unit test

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rcj1 added 2 commits March 21, 2026 07:33

Update ComWrappers_1.cs

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Update ComWrappersDumpTests.cs

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Update ComWrappers_1.cs

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Comment thread ...e/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ComWrappers_1.cs Outdated

Comment thread src/coreclr/vm/datadescriptor/datadescriptor.inc

Comment thread ...e/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ComWrappers_1.cs

rcj1 added 2 commits March 21, 2026 07:49

Update ComWrappers_1.cs

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Add using directive for System.Reflection.Metadata

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rcj1 merged commit f416dc4 into dotnet:main Mar 21, 2026
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rcj1 deleted the GetObjectComWrappersData branch March 21, 2026 17:49

dotnet-maestro Bot mentioned this pull request Mar 22, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#5588

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