Report RhpInitialDynamicInterfaceDispatch reference in gfids (#103948)

Some subset of tests is failing with control flow guard enabled because we're not able to indirectly call `RhpInitialDynamicInterfaceDispatch`. It's not clear why since we address take this method in C++ source files as well, but we should be reporting this from our object file too and doing that fixes it.

Author: MichalStrehovsky

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/ExternSymbolNode.cs

@@ -55,4 +55,12 @@ public override string ToString()
             return _name.ToString();
         }
     }
+
+    public class AddressTakenExternSymbolNode : ExternSymbolNode
+    {
+        public AddressTakenExternSymbolNode(Utf8String name)
+            : base(name) { }
+
+        public override int ClassCode => -45645737;
+    }
 }

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/InterfaceDispatchCellNode.cs

@@ -61,15 +61,7 @@ public override IEnumerable<DependencyListEntry> GetStaticDependencies(NodeFacto
 
             factory.MetadataManager.GetDependenciesDueToVirtualMethodReflectability(ref result, factory, _targetMethod);
 
-            TargetArchitecture targetArchitecture = factory.Target.Architecture;
-            if (targetArchitecture == TargetArchitecture.ARM)
-            {
-                result.Add(factory.InitialInterfaceDispatchStub, "Initial interface dispatch stub");
-            }
-            else
-            {
-                result.Add(factory.ExternSymbol("RhpInitialDynamicInterfaceDispatch"), "Initial interface dispatch stub");
-            }
+            result.Add(factory.InitialInterfaceDispatchStub, "Initial interface dispatch stub");
 
             // We counter-intuitively ask for a constructed type symbol. This is needed due to IDynamicInterfaceCastable.
             // If this dispatch cell is ever used with an object that implements IDynamicIntefaceCastable, user code will
@@ -81,15 +73,7 @@ public override IEnumerable<DependencyListEntry> GetStaticDependencies(NodeFacto
 
         public override void EncodeData(ref ObjectDataBuilder objData, NodeFactory factory, bool relocsOnly)
         {
-            TargetArchitecture targetArchitecture = factory.Target.Architecture;
-            if (targetArchitecture == TargetArchitecture.ARM)
-            {
-                objData.EmitPointerReloc(factory.InitialInterfaceDispatchStub);
-            }
-            else
-            {
-                objData.EmitPointerReloc(factory.ExternSymbol("RhpInitialDynamicInterfaceDispatch"));
-            }
+            objData.EmitPointerReloc(factory.InitialInterfaceDispatchStub);
 
             // We counter-intuitively ask for a constructed type symbol. This is needed due to IDynamicInterfaceCastable.
             // If this dispatch cell is ever used with an object that implements IDynamicIntefaceCastable, user code will

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/NodeFactory.cs

@@ -44,6 +44,11 @@ public NodeFactory(
             ObjectDataInterner dataInterner)
         {
             _target = context.Target;
+
+            InitialInterfaceDispatchStub = _target.Architecture == TargetArchitecture.ARM
+                ? new InitialInterfaceDispatchStubNode()
+                : new AddressTakenExternSymbolNode("RhpInitialDynamicInterfaceDispatch");
+
             _context = context;
             _compilationModuleGroup = compilationModuleGroup;
             _vtableSliceProvider = vtableSliceProvider;
@@ -102,6 +107,11 @@ public NameMangler NameMangler
             get;
         }
 
+        public ISymbolNode InitialInterfaceDispatchStub
+        {
+            get;
+        }
+
         public PreinitializationManager PreinitializationManager
         {
             get;

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/Target_ARM/ARMNodeFactory.cs

@@ -469,7 +469,7 @@ private void EmitObject(string objectFilePath, IReadOnlyCollection<DependencyNod
                         relocTarget.Offset);
 
                     if (_options.HasFlag(ObjectWritingOptions.ControlFlowGuard) &&
-                        relocTarget is IMethodNode or AssemblyStubNode)
+                        relocTarget is IMethodNode or AssemblyStubNode or AddressTakenExternSymbolNode)
                     {
                         // For now consider all method symbols address taken.
                         // We could restrict this in the future to those that are referenced from

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/ObjectWriter.cs

@@ -530,7 +530,6 @@
     <Compile Include="Compiler\DependencyAnalysis\StringAllocatorMethodNode.cs" />
     <Compile Include="Compiler\DependencyAnalysis\Target_X64\X64ReadyToRunGenericHelperNode.cs" />
     <Compile Include="Compiler\DependencyAnalysis\Target_ARM\ARMInitialInterfaceDispatchStubNode.cs" />
-    <Compile Include="Compiler\DependencyAnalysis\Target_ARM\ARMNodeFactory.cs" />
     <Compile Include="Compiler\DependencyAnalysis\VTableSliceNode.cs" />
     <Compile Include="Compiler\DependencyAnalysis\EETypeOptionalFieldsNode.cs" />
     <Compile Include="Compiler\DependencyAnalysis\EmbeddedObjectNode.cs" />