[R2R] Expand discovery of non-generic virtual methods on generic types by BrzVlad · Pull Request #128652 · dotnet/runtime

BrzVlad · 2026-05-27T15:47:59Z

We determine the full set of used generic methods by tracking all types from the app via InheritedVirtualMethodsNode and GVM callsites via GVMDependencies node. The GVMDependencies node then tries to resolve the method on all types from the app, which are a dynamic dependency for this node. This only handles generic methods so, non-generic methods on generic types are not resolved with this mechansim.

This PR completes the support. This is done by adding conditional dependencies to InheritedVirtualMethodsNode. For a generic type, we determine all virtual/interface method slots and the resolved target method. Then we add a conditional dependency that says that the resolved method is included if the slot defining method is used in the app. We detect if the slot defining method is used by creating a VirtualMethodUseNode at callsites.

Methods failing to compile before, from this set of tests: https://gist.github.com/BrzVlad/7ea5987ec494705ac7b4b6aaf1325fe7

Test1Base`1[int]:Test1Method()
Test2C`1[int]:Test2Method()
ITest3WithDim`1[int]:ITest3Base.Test3Method()
Test4A`1[int]:ITest4<T>.Test4Method()
Test5B`1[int]:Test5Method()
Test6B`1[int]:Test6Method()
ITest7`1[int]:Test7Method()

BrzVlad · 2026-05-27T15:48:47Z

/azp run runtime-coreclr crossgen2 outerloop

azure-pipelines · 2026-05-27T15:48:59Z

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Pull request overview

This PR extends crossgen2/ReadyToRun virtual-dispatch dependency discovery so that non-generic virtual method slots on generic type instantiations can trigger compilation of the correct concrete implementations (in addition to the existing GVM (generic virtual method) mechanism).

Changes:

Introduces a new VirtualMethodUseNode marker and a corresponding cache on NodeFactory.
Marks non-GVM virtual slots as “used” from MethodFixupSignature for VirtualEntry fixups.
Adds conditional static dependencies to InheritedVirtualMethodsNode to compile per-type implementations when a corresponding slot is marked used, and broadens type discovery in TypeFixupSignature to enqueue the node.

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

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File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Adds the new `VirtualMethodUseNode` source file to the project.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs	New dependency-analysis marker node representing a used non-GVM virtual slot.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRunCodegenNodeFactory.cs	Adds a node cache + factory method for `VirtualMethodUseNode`.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeFixupSignature.cs	Expands type discovery to add `InheritedVirtualMethodsNode` when virtual slots/interfaces are present.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/MethodFixupSignature.cs	Marks non-GVM virtual slots as used for `VirtualEntry` fixups to enable conditional compilation.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/InheritedVirtualMethodsNode.cs	Adds conditional static dependencies to compile implementations based on `VirtualMethodUseNode` conditions (class + interface paths).

We determine the full set of used generic methods by tracking all types from the app via InheritedVirtualMethodsNode and GVM callsites via GVMDependencies node. The GVMDependencies node then tries to resolve the method on all types from the app, which are a dynamic dependency for this node. This only handles generic methods so, non-generic methods on generic types are not resolved with this mechansim. This PR completes the support. This is done by adding conditional dependencies to InheritedVirtualMethodsNode. For a generic type, we determine all virtual/interface method slots and the resolved target method. Then we add a conditional dependency that says that the resolved method is included if the slot defining method is used in the app. We detect if the slot defining method is used by creating a VirtualMethodUseNode at callsites.

It serves the same purpose both for R2R and NativeAOT

BrzVlad · 2026-06-09T05:03:02Z

/azp run runtime-coreclr crossgen2 outerloop

azure-pipelines · 2026-06-09T05:03:11Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

src/coreclr/tools/Common/Compiler/DependencyAnalysis/VirtualMethodUseNode.cs:22

Changing VirtualMethodUseNode to public introduces new public surface area in compiler infrastructure. Unless this is intentionally a supported API, it should stay internal (and ideally be hidden behind a base return type) to avoid committing to it long-term and to avoid requiring API-approval tracking.


+        private NodeCache<MethodDesc, VirtualMethodUseNode> _virtualMethodUseNodes;
+
+        public VirtualMethodUseNode VirtualMethodUse(MethodDesc method)


            if (!_typeDesc.IsGenericDefinition &&
                !_typeDesc.IsInterface &&
                _typeDesc.IsDefType &&
                (factory.CompilationCurrentPhase == 0) &&
-                factory.CompilationModuleGroup.VersionsWithType(_typeDesc) &&
-                TypeHasGVMSlots(_typeDesc))
+                factory.CompilationModuleGroup.VersionsWithType(_typeDesc))


+            // For non-GVM virtual method calls, mark the virtual slot as used so that
+            // conditional dependencies on InheritedVirtualMethodsNode can trigger compilation
+            // of concrete implementations.
+            if (_fixupKind == ReadyToRunFixupKind.VirtualEntry &&
+                Method.IsVirtual &&


BrzVlad · 2026-06-09T05:26:11Z

+        public override IEnumerable<CombinedDependencyListEntry> SearchDynamicDependencies(List<DependencyNodeCore<NodeFactory>> markedNodes, int firstNode, NodeFactory context) => null;
+
+        public override IEnumerable<CombinedDependencyListEntry> GetConditionalStaticDependencies(NodeFactory factory)
+        {


@MichalStrehovsky this would be the equivalent of EETypeNode.GetConditionalStaticDependencies. The code here share some logic with it as well as with the resolving of target method from GVMDependenciesNode. Unfortunately, I couldn't see an easy way to reuse the pieces from there, also without degrading clarity.

Copilot AI review requested due to automatic review settings May 27, 2026 15:48

Copilot started reviewing on behalf of BrzVlad May 27, 2026 15:48 View session

github-actions Bot added the area-crossgen2-coreclr only use for closed issues label May 27, 2026

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This was referenced May 28, 2026

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

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XHarness package install failure on iOS due to devicectl NSPOSIXErrorDomain error 49 #123796

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BrzVlad force-pushed the feature-r2r-generics-non-gvm branch from 68f23ac to f924912 Compare June 8, 2026 16:22

This was referenced Jun 8, 2026

System.Text.Json.Tests fails with GC hole assert #117186

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

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BrzVlad added 2 commits June 9, 2026 08:01

Avoid code duplication of VirtualMethodUseNode

ff3d0a6

It serves the same purpose both for R2R and NativeAOT

Copilot AI review requested due to automatic review settings June 9, 2026 05:01

BrzVlad force-pushed the feature-r2r-generics-non-gvm branch from f924912 to ff3d0a6 Compare June 9, 2026 05:01

Copilot started reviewing on behalf of BrzVlad June 9, 2026 05:02 View session

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BrzVlad commented Jun 9, 2026

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BrzVlad marked this pull request as ready for review June 9, 2026 05:26

BrzVlad requested a review from MichalStrehovsky as a code owner June 9, 2026 05:26

build-analysis Bot mentioned this pull request Jun 9, 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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[R2R] Expand discovery of non-generic virtual methods on generic types#128652

[R2R] Expand discovery of non-generic virtual methods on generic types#128652
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BrzVlad:feature-r2r-generics-non-gvm

BrzVlad commented May 27, 2026 •

edited

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		private NodeCache<MethodDesc, VirtualMethodUseNode> _virtualMethodUseNodes;

		public VirtualMethodUseNode VirtualMethodUse(MethodDesc method)

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BrzVlad commented May 27, 2026 •

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