From 4f6f7effd99d2941d419f4900e370ceef1e83621 Mon Sep 17 00:00:00 2001
From: Siegfried Pammer <siegfriedpammer@gmail.com>
Date: Sat, 29 Jan 2022 15:12:43 +0100
Subject: [PATCH] #2594: Add AnalyzerHelpers.IsPossibleReferenceTo for methods
 to speed MethodUsedByAnalyzer

---
 ILSpy/Analyzers/AnalyzerHelpers.cs            | 52 +++++++++++++++++++
 .../Analyzers/Builtin/MethodUsedByAnalyzer.cs | 18 ++++---
 2 files changed, 62 insertions(+), 8 deletions(-)
 create mode 100644 ILSpy/Analyzers/AnalyzerHelpers.cs

diff --git a/ILSpy/Analyzers/AnalyzerHelpers.cs b/ILSpy/Analyzers/AnalyzerHelpers.cs
new file mode 100644
index 000000000..a4b8c6432
--- /dev/null
+++ b/ILSpy/Analyzers/AnalyzerHelpers.cs
@@ -0,0 +1,52 @@
+// Copyright (c) 2018 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Reflection.Metadata;
+
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.ILSpy.Analyzers
+{
+	using ICSharpCode.Decompiler.TypeSystem;
+
+	internal static class AnalyzerHelpers
+	{
+		public static bool IsPossibleReferenceTo(EntityHandle member, PEFile module, IMethod analyzedMethod)
+		{
+			if (member.IsNil)
+				return false;
+			MetadataReader metadata = module.Metadata;
+			switch (member.Kind)
+			{
+				case HandleKind.MethodDefinition:
+					return member == analyzedMethod.MetadataToken
+						&& module == analyzedMethod.ParentModule.PEFile;
+				case HandleKind.MemberReference:
+					var mr = metadata.GetMemberReference((MemberReferenceHandle)member);
+					if (mr.GetKind() != MemberReferenceKind.Method)
+						return false;
+					return metadata.StringComparer.Equals(mr.Name, analyzedMethod.Name);
+				case HandleKind.MethodSpecification:
+					var ms = metadata.GetMethodSpecification((MethodSpecificationHandle)member);
+					return IsPossibleReferenceTo(ms.Method, module, analyzedMethod);
+				default:
+					return false;
+			}
+		}
+	}
+}
diff --git a/ILSpy/Analyzers/Builtin/MethodUsedByAnalyzer.cs b/ILSpy/Analyzers/Builtin/MethodUsedByAnalyzer.cs
index a94121993..80fa96326 100644
--- a/ILSpy/Analyzers/Builtin/MethodUsedByAnalyzer.cs
+++ b/ILSpy/Analyzers/Builtin/MethodUsedByAnalyzer.cs
@@ -117,7 +117,7 @@ namespace ICSharpCode.ILSpy.Analyzers.Builtin
 			var mainModule = (MetadataModule)method.ParentModule;
 			var blob = methodBody.GetILReader();
 
-			var baseMethod = InheritanceHelper.GetBaseMember(analyzedMethod);
+			var baseMethod = (IMethod)InheritanceHelper.GetBaseMember(analyzedMethod);
 			var genericContext = new Decompiler.TypeSystem.GenericContext(); // type parameters don't matter for this analyzer
 
 			while (blob.RemainingBytes > 0)
@@ -137,8 +137,13 @@ namespace ICSharpCode.ILSpy.Analyzers.Builtin
 					return false; // unexpected end of blob
 				}
 				var member = MetadataTokenHelpers.EntityHandleOrNil(blob.ReadInt32());
-				if (member.IsNil || !member.Kind.IsMemberKind())
-					continue;
+				if (!AnalyzerHelpers.IsPossibleReferenceTo(member, mainModule.PEFile, analyzedMethod))
+				{
+					if (baseMethod == null || !AnalyzerHelpers.IsPossibleReferenceTo(member, mainModule.PEFile, baseMethod))
+					{
+						continue;
+					}
+				}
 
 				IMember m;
 				try
@@ -159,12 +164,9 @@ namespace ICSharpCode.ILSpy.Analyzers.Builtin
 						return true;
 					}
 				}
-				else
+				if (IsSameMember(analyzedMethod, m))
 				{
-					if (IsSameMember(analyzedMethod, m))
-					{
-						return true;
-					}
+					return true;
 				}
 			}