#1682, #1949 and #2394: Added basic algorithm of IsInterfaceImplementationRuntimeHelper

ICSharpCode.Decompiler.Tests/TestCases/Pretty/MemberTests.cs

@@ -24,19 +24,57 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 {
 	internal class MemberTests
 	{
+#if CS72
+		public interface IC
+		{
+			int MMM(in int x);
+		}
+
+		public class C : IC
+		{
+			public int MMM(in int x)
+			{
+				return x;
+			}
+		}
+
+		public interface IC2
+		{
+			object MMM(in object x);
+			int MMM2(ref int x);
+		}
+
+		public class C2 : IC2
+		{
+			public object MMM(in dynamic x)
+			{
+				return x;
+			}
+
+			public int MMM2(in int x)
+			{
+				return x;
+			}
+
+			int IC2.MMM2(ref int x)
+			{
+				return MMM2(in x);
+			}
+		}
+#endif
 		public class IndexerNonDefaultName
 		{
 			[IndexerName("Foo")]
 #if ROSLYN
 			public int this[int index] => 0;
 #else
-			#pragma warning disable format
+#pragma warning disable format
 			public int this[int index] {
 				get {
 					return 0;
 				}
 			}
-			#pragma warning restore format
+#pragma warning restore format
 #endif
 		}
 

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -22,6 +22,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Reflection.Metadata;
+using System.Reflection.Metadata.Ecma335;
 using System.Reflection.PortableExecutable;
 using System.Text.RegularExpressions;
 using System.Threading;
@@ -284,6 +285,8 @@ namespace ICSharpCode.Decompiler.CSharp
 					var methodSemantics = module.MethodSemanticsLookup.GetSemantics(methodHandle).Item2;
 					if (methodSemantics != 0 && methodSemantics != System.Reflection.MethodSemanticsAttributes.Other)
 						return true;
+					if (IsInterfaceImplementationRuntimeHelper(module, methodHandle, methodSemantics))
+						return true;
 					if (settings.LocalFunctions && LocalFunctionDecompiler.IsLocalFunctionMethod(module, methodHandle))
 						return true;
 					if (settings.AnonymousMethods && methodHandle.HasGeneratedName(metadata) && methodHandle.IsCompilerGenerated(metadata))
@@ -376,6 +379,135 @@ namespace ICSharpCode.Decompiler.CSharp
 			return false;
 		}
 
+		static bool IsInterfaceImplementationRuntimeHelper(PEFile module, MethodDefinitionHandle handle, System.Reflection.MethodSemanticsAttributes methodSemantics)
+		{
+			var metadata = module.Metadata;
+			var method = metadata.GetMethodDefinition(handle);
+			if ((method.Attributes & System.Reflection.MethodAttributes.Static) != 0)
+				return false;
+			string rawName = metadata.GetString(method.Name);
+			int dot = rawName.LastIndexOf('.');
+			if (dot < 0)
+				return false;
+			string name = rawName.Substring(dot + 1);
+			if (handle.GetMethodImplementations(metadata).Length == 0)
+				return false;
+			if (method.RelativeVirtualAddress == 0)
+				return false;
+			var signature = metadata.GetBlobReader(method.Signature);
+			(int genericParameterCount, int parameterCount) = SignatureBlobComparer.ReadParameterCount(ref signature);
+			if (genericParameterCount == -1 || parameterCount == -1)
+				return false;
+			signature.Reset();
+
+			int maximumMethodSize = 4 * (parameterCount + 1) + 5 + 1;
+
+			var body = module.Reader.GetMethodBody(method.RelativeVirtualAddress);
+			var reader = body.GetILReader();
+
+			if (reader.RemainingBytes > maximumMethodSize)
+				return false;
+
+			for (int i = 0; i < parameterCount + 1; i++)
+			{
+				int index;
+				switch (reader.DecodeOpCode())
+				{
+					case ILOpCode.Ldarg:
+						index = reader.ReadUInt16();
+						if (index != i)
+							return false;
+						break;
+					case ILOpCode.Ldarg_s:
+						index = reader.ReadByte();
+						if (index != i)
+							return false;
+						break;
+					case ILOpCode.Ldarg_0:
+						if (i != 0)
+							return false;
+						break;
+					case ILOpCode.Ldarg_1:
+						if (i != 1)
+							return false;
+						break;
+					case ILOpCode.Ldarg_2:
+						if (i != 2)
+							return false;
+						break;
+					case ILOpCode.Ldarg_3:
+						if (i != 3)
+							return false;
+						break;
+					default:
+						return false;
+				}
+			}
+
+			if (reader.DecodeOpCode() != ILOpCode.Call)
+				return false;
+
+			EntityHandle targetHandle = MetadataTokenHelpers.EntityHandleOrNil(reader.ReadInt32());
+			if (targetHandle.IsNil)
+				return false;
+
+			if (reader.DecodeOpCode() != ILOpCode.Ret)
+				return false;
+
+			if (reader.RemainingBytes != 0)
+				return false;
+
+			BlobReader signature2;
+			string otherName;
+
+			switch (targetHandle.Kind)
+			{
+				case HandleKind.MethodDefinition:
+					if (genericParameterCount != 0)
+						return false;
+					var methodDef = metadata.GetMethodDefinition((MethodDefinitionHandle)targetHandle);
+					signature2 = metadata.GetBlobReader(methodDef.Signature);
+					otherName = metadata.GetString(methodDef.Name);
+					break;
+				case HandleKind.MethodSpecification:
+					if (genericParameterCount == 0)
+						return false;
+					var methodSpec = metadata.GetMethodSpecification((MethodSpecificationHandle)targetHandle);
+					var instantiation = methodSpec.DecodeSignature(MetadataExtensions.MinimalSignatureTypeProvider, default);
+					switch (methodSpec.Method.Kind)
+					{
+						case HandleKind.MethodDefinition:
+							var methodSpecDef = metadata.GetMethodDefinition((MethodDefinitionHandle)methodSpec.Method);
+							signature2 = metadata.GetBlobReader(methodSpecDef.Signature);
+							otherName = metadata.GetString(methodSpecDef.Name);
+							break;
+						case HandleKind.MemberReference:
+							var methodSpecRef = metadata.GetMemberReference((MemberReferenceHandle)methodSpec.Method);
+							if (methodSpecRef.GetKind() != MemberReferenceKind.Method)
+								return false;
+							signature2 = metadata.GetBlobReader(methodSpecRef.Signature);
+							otherName = metadata.GetString(methodSpecRef.Name);
+							break;
+						default:
+							return false;
+					}
+					break;
+				case HandleKind.MemberReference:
+					var methodRef = metadata.GetMemberReference((MemberReferenceHandle)targetHandle);
+					if (methodRef.GetKind() != MemberReferenceKind.Method)
+						return false;
+					signature2 = metadata.GetBlobReader(methodRef.Signature);
+					otherName = metadata.GetString(methodRef.Name);
+					break;
+				default:
+					return false;
+			}
+
+			if (otherName != name)
+				return false;
+			return SignatureBlobComparer.EqualsMethodSignature(signature, signature2, metadata, metadata);
+		}
+
 		static bool IsSwitchOnStringCache(SRM.FieldDefinition field, MetadataReader metadata)
 		{
 			return metadata.GetString(field.Name).StartsWith("<>f__switch", StringComparison.Ordinal);

ICSharpCode.Decompiler/Metadata/SignatureBlobComparer.cs

@@ -22,12 +22,41 @@ namespace ICSharpCode.Decompiler.Metadata
 {
 	public static class SignatureBlobComparer
 	{
+		internal static (int GenericParameterCount, int ParameterCount) ReadParameterCount(ref BlobReader reader)
+		{
+			if (reader.RemainingBytes == 0)
+				return (-1, -1);
+
+			var header = reader.ReadSignatureHeader();
+			int gp;
+			if (header.IsGeneric)
+			{
+				if (!reader.TryReadCompressedInteger(out gp))
+					gp = -1;
+			}
+			else
+			{
+				gp = 0;
+			}
+
+			if (!reader.TryReadCompressedInteger(out int p))
+				p = -1;
+
+			return (gp, p);
+		}
+
 		public static bool EqualsMethodSignature(BlobReader a, BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
 		{
-			return EqualsMethodSignature(ref a, ref b, contextForA, contextForB);
+			return EqualsMethodSignature(ref a, ref b, contextForA, contextForB, false);
 		}
 
-		static bool EqualsMethodSignature(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
+		public static bool EqualsMethodSignature(BlobReader a, BlobReader b, MetadataReader contextForA, MetadataReader contextForB, bool skipModifiers)
+		{
+			return EqualsMethodSignature(ref a, ref b, contextForA, contextForB, skipModifiers);
+		}
+
+		static bool EqualsMethodSignature(ref BlobReader a, ref BlobReader b,
+			MetadataReader contextForA, MetadataReader contextForB, bool skipModifiers)
 		{
 			SignatureHeader header;
 			// compare signature headers
@@ -44,7 +73,7 @@ namespace ICSharpCode.Decompiler.Metadata
 				return false;
 			if (!IsSameCompressedInteger(ref a, ref b, out int typeCode))
 				return false;
-			if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+			if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 				return false;
 			int i = 0;
 			for (; i < totalParameterCount; i++)
@@ -54,14 +83,14 @@ namespace ICSharpCode.Decompiler.Metadata
 				// varargs sentinel
 				if (typeCode == 65)
 					break;
-				if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+				if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 					return false;
 			}
 			for (; i < totalParameterCount; i++)
 			{
 				if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 					return false;
-				if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+				if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 					return false;
 			}
 			return true;
@@ -76,7 +105,7 @@ namespace ICSharpCode.Decompiler.Metadata
 		{
 			if (!IsSameCompressedInteger(ref a, ref b, out int typeCode))
 				return false;
-			return TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode);
+			return TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, false);
 		}
 
 		static bool IsSameCompressedInteger(ref BlobReader a, ref BlobReader b, out int value)
@@ -89,7 +118,7 @@ namespace ICSharpCode.Decompiler.Metadata
 			return a.TryReadCompressedSignedInteger(out value) && b.TryReadCompressedSignedInteger(out int otherValue) && value == otherValue;
 		}
 
-		static bool TypesAreEqual(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB, int typeCode)
+		static bool TypesAreEqual(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB, int typeCode, bool skipModifiers)
 		{
 			switch (typeCode)
 			{
@@ -118,18 +147,18 @@ namespace ICSharpCode.Decompiler.Metadata
 				case 0x1D: // ELEMENT_TYPE_SZARRAY
 					if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 						return false;
-					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 						return false;
 					return true;
 				case 0x1B: // ELEMENT_TYPE_FNPTR 
-					if (!EqualsMethodSignature(ref a, ref b, contextForA, contextForB))
+					if (!EqualsMethodSignature(ref a, ref b, contextForA, contextForB, skipModifiers))
 						return false;
 					return true;
 				case 0x14: // ELEMENT_TYPE_ARRAY 
 						   // element type
 					if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 						return false;
-					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 						return false;
 					// rank
 					if (!IsSameCompressedInteger(ref a, ref b, out _))
@@ -154,19 +183,19 @@ namespace ICSharpCode.Decompiler.Metadata
 				case 0x1F: // ELEMENT_TYPE_CMOD_REQD 
 				case 0x20: // ELEMENT_TYPE_CMOD_OPT 
 						   // modifier
-					if (!TypeHandleEquals(ref a, ref b, contextForA, contextForB))
+					if (!TypeHandleEquals(ref a, ref b, contextForA, contextForB) && !skipModifiers)
 						return false;
 					// unmodified type
 					if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 						return false;
-					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 						return false;
 					return true;
 				case 0x15: // ELEMENT_TYPE_GENERICINST 
 						   // generic type
 					if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 						return false;
-					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+					if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 						return false;
 					if (!IsSameCompressedInteger(ref a, ref b, out int numOfArguments))
 						return false;
@@ -174,7 +203,7 @@ namespace ICSharpCode.Decompiler.Metadata
 					{
 						if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
 							return false;
-						if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
+						if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode, skipModifiers))
 							return false;
 					}
 					return true;
@@ -200,6 +229,8 @@ namespace ICSharpCode.Decompiler.Metadata
 			var typeB = b.ReadTypeHandle();
 			if (typeA.IsNil || typeB.IsNil)
 				return false;
+			if (contextForA == contextForB)
+				return typeA.Equals(typeB);
 			return typeA.GetFullTypeName(contextForA) == typeB.GetFullTypeName(contextForB);
 		}
 	}