Reuse metadata signature encoder

Build the cached signatures through the existing SRM encoder so the optimization stays small and preserves the established encoding path.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: simonrozsival

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/PEAssemblyBuilder.cs

@@ -159,15 +159,18 @@ public AssemblyReferenceHandle FindOrAddAssemblyRef (string assemblyName)
 	/// Adds a member reference using the reusable signature blob builder.
 	/// </summary>
 	public MemberReferenceHandle AddMemberRef (EntityHandle parent, string name, Action<BlobEncoder> encodeSig)
+		=> AddMemberRef (parent, name, GetOrAddSignature (encodeSig));
+
+	public MemberReferenceHandle AddMemberRef (EntityHandle parent, string name, BlobHandle signature)
+		=> Metadata.AddMemberReference (parent, Metadata.GetOrAddString (name), signature);
+
+	public BlobHandle GetOrAddSignature (Action<BlobEncoder> encodeSig)
 	{
 		_sigBlob.Clear ();
 		encodeSig (new BlobEncoder (_sigBlob));
-		return AddMemberRef (parent, name, Metadata.GetOrAddBlob (_sigBlob));
+		return Metadata.GetOrAddBlob (_sigBlob);
 	}
 
-	public MemberReferenceHandle AddMemberRef (EntityHandle parent, string name, BlobHandle signature)
-		=> Metadata.AddMemberReference (parent, Metadata.GetOrAddString (name), signature);
-
 	/// <summary>
 	/// Resolves a <see cref="TypeRefData"/> to a TypeReference/TypeSpecification handle, with caching.
 	/// </summary>
@@ -416,11 +419,9 @@ public MethodDefinitionHandle EmitBody (string name, MethodAttributes attrs,
 		Action<BlobEncoder> encodeSig, Action<TrackedInstructionEncoder> emitIL,
 		Action<BlobBuilder>? encodeLocals, bool useBranches)
 	{
-		_sigBlob.Clear ();
-		encodeSig (new BlobEncoder (_sigBlob));
 		// Capture the sig blob handle before emitIL, because emitIL callbacks
 		// may call AddMemberRef which clears and repopulates _sigBlob.
-		return EmitBody (name, attrs, Metadata.GetOrAddBlob (_sigBlob), emitIL, encodeLocals, useBranches);
+		return EmitBody (name, attrs, GetOrAddSignature (encodeSig), emitIL, encodeLocals, useBranches);
 	}
 
 	MethodDefinitionHandle EmitBody (string name, MethodAttributes attrs,

src/Microsoft.Android.Sdk.TrimmableTypeMap/Generator/TypeMapAssemblyEmitter.cs

@@ -974,30 +974,27 @@ MemberReferenceHandle AddActivationCtorRef (EntityHandle declaringTypeRef)
 	BlobHandle GetActivationCtorSignature ()
 	{
 		if (_activationCtorSignature.IsNil) {
-			var blob = new BlobBuilder (8);
-			blob.WriteByte ((byte) SignatureAttributes.Instance);
-			blob.WriteCompressedInteger (2);
-			blob.WriteByte ((byte) SignatureTypeCode.Void);
-			blob.WriteByte ((byte) SignatureTypeCode.IntPtr);
-			blob.WriteByte ((byte) SignatureTypeKind.ValueType);
-			blob.WriteCompressedInteger (CodedIndex.TypeDefOrRefOrSpec (_jniHandleOwnershipRef));
-			_activationCtorSignature = _pe.Metadata.GetOrAddBlob (blob);
+			_activationCtorSignature = _pe.GetOrAddSignature (
+				sig => sig.MethodSignature (isInstanceMethod: true).Parameters (2,
+					rt => rt.Void (),
+					p => {
+						p.AddParameter ().Type ().IntPtr ();
+						p.AddParameter ().Type ().Type (_jniHandleOwnershipRef, true);
+					}));
 		}
 		return _activationCtorSignature;
 	}
 
 	BlobHandle GetCreateInstanceSignature ()
 	{
 		if (_createInstanceSignature.IsNil) {
-			var blob = new BlobBuilder (8);
-			blob.WriteByte ((byte) SignatureAttributes.Instance);
-			blob.WriteCompressedInteger (2);
-			blob.WriteByte ((byte) SignatureTypeKind.Class);
-			blob.WriteCompressedInteger (CodedIndex.TypeDefOrRefOrSpec (_iJavaPeerableRef));
-			blob.WriteByte ((byte) SignatureTypeCode.IntPtr);
-			blob.WriteByte ((byte) SignatureTypeKind.ValueType);
-			blob.WriteCompressedInteger (CodedIndex.TypeDefOrRefOrSpec (_jniHandleOwnershipRef));
-			_createInstanceSignature = _pe.Metadata.GetOrAddBlob (blob);
+			_createInstanceSignature = _pe.GetOrAddSignature (
+				sig => sig.MethodSignature (isInstanceMethod: true).Parameters (2,
+					rt => rt.Type ().Type (_iJavaPeerableRef, false),
+					p => {
+						p.AddParameter ().Type ().IntPtr ();
+						p.AddParameter ().Type ().Type (_jniHandleOwnershipRef, true);
+					}));
 		}
 		return _createInstanceSignature;
 	}