Adding GetHandleEnum and GetHandleEnumForTypes cDAC APIs by rcj1 · Pull Request #124760 · dotnet/runtime

rcj1 · 2026-02-23T18:56:39Z

dotnet-policy-service · 2026-02-23T18:57:48Z

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Copilot

Pull request overview

This pull request implements the GetHandleEnum and GetHandleEnumForTypes cDAC APIs, enabling enumeration of GC handles through the contract-based data access interface. The implementation adds handle enumeration support that can operate independently of the legacy DAC while maintaining backward compatibility for validation in DEBUG builds.

Changes:

Implements SOSHandleEnum class that wraps handle data retrieval from the GC contract and provides COM enumeration semantics
Adds GC contract methods GetHandles and GetSupportedHandleTypes to retrieve handle information from handle table structures
Extends ComWrappers contract with GetRefCount and IsHandleWeak methods to support refcounted handle interrogation

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
SOSDacImpl.cs	Implements SOSHandleEnum class and GetHandleEnum/GetHandleEnumForTypes interface methods with legacy DAC comparison in DEBUG builds
ISOSDacInterface.cs	Defines ISOSHandleEnum interface and SOSHandleData structure; updates GetHandleEnum/GetHandleEnumForTypes signatures to use typed interfaces instead of void pointers
GC_1.cs	Implements GetHandles and GetSupportedHandleTypes methods that traverse handle table structures and populate handle data including COM refcount info
GCFactory.cs	Updates GC_1 constructor to receive handle-related global constants
ComWrappers_1.cs	Adds GetRefCount and IsHandleWeak methods to interrogate COM call wrapper properties
TableSegment.cs	New data structure representing a segment of the handle table with handle block metadata
SimpleComCallWrapper.cs	New data structure containing COM wrapper refcount and flags
HandleTableMap.cs	New data structure representing the handle table map with bucket array
HandleTableBucket.cs	New data structure representing a handle table bucket
HandleTable.cs	New data structure representing a handle table with segment list
ComCallWrapper.cs	New data structure representing a COM call wrapper with pointer to SimpleComCallWrapper
datadescriptor.inc (VM)	Adds data descriptors for ComCallWrapper and SimpleComCallWrapper types; adds feature flags and ComRefcountMask global
datadescriptor.h (VM)	Includes comcallablewrapper.h for cdac_data template specializations
comcallablewrapper.h	Adds cdac_data friend declarations and template specializations for ComCallWrapper and SimpleComCallWrapper offset definitions
datadescriptor.inc (GC)	Adds data descriptors for handle table structures and related globals
datadescriptor.h (GC)	Includes handletablepriv.h for handle table structure definitions
Constants.cs	Adds global constant names for feature flags, handle table configuration, and COM refcount mask
DataType.cs	Adds enum values for new handle table and COM wrapper data types
IGC.cs	Adds HandleData record struct and GetHandles/GetSupportedHandleTypes interface methods
IComWrappers.cs	Adds GetRefCount and IsHandleWeak interface methods
GC.md	Documents GetHandles and GetSupportedHandleTypes contract methods with implementation details
ComWrappers.md	Documents GetRefCount and IsHandleWeak contract methods

...ative/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/HandleTableMap.cs

...ve/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/HandleTableBucket.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/HandleTable.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

docs/design/datacontracts/GC.md

src/coreclr/gc/datadescriptor/datadescriptor.inc

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 3 comments.

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs

docs/design/datacontracts/GC.md

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 7 comments.

docs/design/datacontracts/ComWrappers.md

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

src/coreclr/vm/datadescriptor/datadescriptor.inc

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs

docs/design/datacontracts/GC.md

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 8 comments.

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

...ative/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/ComCallWrapper.cs

...ve/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GCFactory.cs

src/coreclr/vm/datadescriptor/datadescriptor.inc

...managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/SimpleComCallWrapper.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/TableSegment.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 27 out of 27 changed files in this pull request and generated 11 comments.

...ve/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GCFactory.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

Copilot · 2026-02-24T22:26:36Z

docs/design/datacontracts/GC.md

+List<HandleData> IGC.GetHandles(uint[] types)
+{
+    List<HandleData> handles = new();
+    TargetPointer handleTableMap = target.ReadGlobalPointer("HandleTableMap");
+    // for each handleTableMap in the linked list


The GetHandles design snippet is out of sync with the implementation: the API was added as IGC.GetHandles(HandleType[] types), but the docs show uint[] types. Also HandleTableMap is a CDAC_GLOBAL_POINTER(&g_HandleTableMap), so the sample should dereference the global pointer once before treating it as a HandleTableMap*.

...ative/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/ContractRegistry.cs

src/native/managed/cdac/tests/DumpTests/WorkstationGCDumpTests.cs

docs/design/datacontracts/ComWrappers.md

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader/CachingContractRegistry.cs

Copilot · 2026-02-24T22:26:38Z

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

+                (uint)HandleType_1.RefCounted => HandleType.RefCounted,
+                (uint)HandleType_1.Dependent => HandleType.Dependent,
+                (uint)HandleType_1.WeakInteriorPointer => HandleType.WeakInteriorPointer,
+                (uint)HandleType_1.CrossReference => HandleType.CrossReference,
+                _ => throw new InvalidOperationException($"Unknown handle type {type}"),


GetHandleTypes throws for unrecognized handle type values. The native DAC typemask builder accepts arbitrary type values (< 32) and just results in “no handles” for unsupported types; throwing here can break forward-compat callers. Prefer ignoring unknown types (or filtering to known/supported ones) instead of throwing.

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 31 out of 31 changed files in this pull request and generated 3 comments.

docs/design/datacontracts/BuiltInCOM.md

docs/design/datacontracts/GC.md

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

Copilot

Pull request overview

Copilot reviewed 33 out of 33 changed files in this pull request and generated 6 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/datadescriptor/datadescriptor.inc:1204

CDAC_GLOBAL_CONTRACT(BuiltInCOM, 1) is currently unconditional, but the contract implementation and its data descriptors/globals are only valid when FEATURE_COMINTEROP is enabled. Consider guarding this contract registration with #if FEATURE_COMINTEROP (similar to ComWrappers) so targets that don't support built-in COM don't advertise a non-functional contract.


CDAC_GLOBAL_CONTRACT(BuiltInCOM, 1)
CDAC_GLOBAL_CONTRACT(CodeVersions, 1)
#ifdef FEATURE_COMWRAPPERS
CDAC_GLOBAL_CONTRACT(ComWrappers, 1)
#endif // FEATURE_COMWRAPPERS

...tive/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/BuiltInCOM.cs

src/coreclr/gc/gcinterface.h

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/GC/GC_1.cs

src/native/managed/cdac/tests/DumpTests/WorkstationGCDumpTests.cs

docs/design/datacontracts/ComWrappers.md

Copilot

Pull request overview

Copilot reviewed 33 out of 33 changed files in this pull request and generated 3 comments.

...ative/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/HandleTableMap.cs

src/coreclr/vm/datadescriptor/datadescriptor.inc

docs/design/datacontracts/BuiltInCOM.md

Co-authored-by: Copilot <[email protected]>

Copilot

Pull request overview

Copilot reviewed 33 out of 33 changed files in this pull request and generated no new comments.

adding GetHandleForEnum cDAC API

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Merge branch 'main' into GetHandleEnum

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rcj1 mentioned this pull request Feb 25, 2026

GC handle enumeration bug #124872

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rcj1 commented Feb 23, 2026 •

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