Generate single interface dispatch map per canonical form (#76362)

The dispatch maps are identical because canonically-equivalent types have the same vtable layouts.
dotnet · Sep 29, 2022 · e5d2c3e · e5d2c3e
1 parent ed9afa8
commit e5d2c3e
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Showing 3 changed files with 5 additions and 2 deletions.
diff --git a/...oreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ConstructedEETypeNode.cs b/...oreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ConstructedEETypeNode.cs
@@ -38,7 +38,8 @@ protected override DependencyList ComputeNonRelocationBasedDependencies(NodeFact
 
             if (MightHaveInterfaceDispatchMap(factory))
             {
-                dependencyList.Add(factory.InterfaceDispatchMap(_type), "Interface dispatch map");
+                TypeDesc canonType = _type.ConvertToCanonForm(CanonicalFormKind.Specific);
+                dependencyList.Add(factory.InterfaceDispatchMap(canonType), "Interface dispatch map");
             }
 
             if (_type.IsArray)

diff --git a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/EETypeNode.cs b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/EETypeNode.cs
@@ -1056,7 +1056,8 @@ protected internal virtual void ComputeOptionalEETypeFields(NodeFactory factory,
         {
             if (!relocsOnly && MightHaveInterfaceDispatchMap(factory))
             {
-                _optionalFieldsBuilder.SetFieldValue(EETypeOptionalFieldTag.DispatchMap, checked((uint)factory.InterfaceDispatchMapIndirection(Type).IndexFromBeginningOfArray));
+                TypeDesc canonType = _type.ConvertToCanonForm(CanonicalFormKind.Specific);
+                _optionalFieldsBuilder.SetFieldValue(EETypeOptionalFieldTag.DispatchMap, checked((uint)factory.InterfaceDispatchMapIndirection(canonType).IndexFromBeginningOfArray));
             }
 
             ComputeRareFlags(factory, relocsOnly);

diff --git a/...clr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/InterfaceDispatchMapNode.cs b/...clr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/InterfaceDispatchMapNode.cs
@@ -22,6 +22,7 @@ public InterfaceDispatchMapNode(NodeFactory factory, TypeDesc type)
             // Pointer arrays also follow the same path
             Debug.Assert(!type.IsArrayTypeWithoutGenericInterfaces());
             Debug.Assert(MightHaveInterfaceDispatchMap(type, factory));
+            Debug.Assert(type.ConvertToCanonForm(CanonicalFormKind.Specific) == type);
 
             _type = type;
         }