[Java.Interop.Tools.JavaCallableWrappers] use less System.Linq for CAs (

#1072)

Context: https://github.com/microsoft/dotnet-podcasts/tree/net8.0

When building the .NET Podcast sample for .NET 8, profiling an
incremental build with a `.xaml` change I noticed:

	80.42ms java.interop.tools.javacallablewrappers!Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.IsNonStaticInnerClass(...

There was a double-nested usage of System.Linq via a
`GetBaseConstructors()` method, so I "unrolled" this to a plain
`foreach` loop.

After this change:

	61.50ms java.interop.tools.javacallablewrappers!Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.IsNonStaticInnerClass(...

This made me review places using System.Linq `.Any()` calls:

	59.78ms System.Linq.il!System.Linq.Enumerable.Any(class System.Collections.Generic.IEnumerable`1<!!0>)
	15.87ms System.Linq.il!System.Linq.Enumerable.Any(class System.Collections.Generic.IEnumerable`1<!!0>,class System.Func`2<!!0,bool>)
	 1.98ms system.linq.il!System.Linq.Enumerable.Any(class System.Collections.Generic.IEnumerable`1<!!0>)

Which I was able to track down to calls to an extension method like:

	CustomAttributeProviderRocks.GetCustomAttributes().Any()

I created a new `CustomAttributeProviderRocks.AnyCustomAttributes()`
extension method, which is a bit better because:

  * We avoid a `yield return` & related compiler machinery.

  * We avoid allocating custom attribute objects in some cases, as
    System.Linq's `.Any()` will enumerate and create at least one.

Before:

	107.90ms java.interop.tools.cecil!Java.Interop.Tools.Cecil.CustomAttributeProviderRocks+<GetCustomAttributes>d__1.MoveNext()
	  3.80ms java.interop.tools.cecil!Java.Interop.Tools.Cecil.CustomAttributeProviderRocks.GetCustomAttributes(class Mono.Cecil.ICus...

After:

	 58.58ms java.interop.tools.cecil!Java.Interop.Tools.Cecil.CustomAttributeProviderRocks.AnyCustomAttributes(class Mono.Cecil.ICustomAttributeProvider,class System.Type)
	 36.01ms java.interop.tools.cecil!Java.Interop.Tools.Cecil.CustomAttributeProviderRocks+<GetCustomAttributes>d__3.MoveNext()
	  1.97ms java.interop.tools.cecil!Java.Interop.Tools.Cecil.CustomAttributeProviderRocks.GetCustomAttributes(class Mono.Cecil.ICus...

These changes are about:

  * `IsNonStaticInnerClass`: ~19ms faster
  * `CustomAttributeProviderRocks (Any)`: ~15ms faster

Overall, saves about ~34ms for incremental builds of the
.NET podcast app.

src/Java.Interop.Tools.Cecil/Java.Interop.Tools.Cecil/CustomAttributeProviderRocks.cs

@@ -8,11 +8,23 @@ namespace Java.Interop.Tools.Cecil {
 
 	public static class CustomAttributeProviderRocks
 	{
+		public static bool AnyCustomAttributes (this ICustomAttributeProvider item, Type attribute) =>
+			item.AnyCustomAttributes (attribute.FullName);
+
 		public static IEnumerable<CustomAttribute> GetCustomAttributes (this ICustomAttributeProvider item, Type attribute)
 		{
 			return item.GetCustomAttributes (attribute.FullName);
 		}
 
+		public static bool AnyCustomAttributes (this ICustomAttributeProvider item, string attribute_fullname)
+		{
+			foreach (CustomAttribute custom_attribute in item.CustomAttributes) {
+				if (custom_attribute.Constructor.DeclaringType.FullName == attribute_fullname)
+					return true;
+			}
+			return false;
+		}
+
 		public static IEnumerable<CustomAttribute> GetCustomAttributes (this ICustomAttributeProvider item, string attribute_fullname)
 		{
 			foreach (CustomAttribute custom_attribute in item.CustomAttributes) {

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/JavaCallableWrapperGenerator.cs

@@ -164,10 +164,10 @@ void AddNestedTypes (TypeDefinition type)
 				var baseRegisteredMethod = GetBaseRegisteredMethod (minfo);
 				if (baseRegisteredMethod != null)
 					AddMethod (baseRegisteredMethod, minfo);
-				else if (GetExportFieldAttributes (minfo).Any ()) {
+				else if (minfo.AnyCustomAttributes (typeof(ExportFieldAttribute))) {
 					AddMethod (null, minfo);
 					HasExport = true;
-				} else if (GetExportAttributes (minfo).Any ()) {
+				} else if (minfo.AnyCustomAttributes (typeof (ExportAttribute))) {
 					AddMethod (null, minfo);
 					HasExport = true;
 				}
@@ -205,8 +205,8 @@ void AddNestedTypes (TypeDefinition type)
 
 			var curCtors = new List<MethodDefinition> ();
 
-			foreach (MethodDefinition minfo in type.Methods.Where (m => m.IsConstructor)) {
-				if (GetExportAttributes (minfo).Any ()) {
+			foreach (MethodDefinition minfo in type.Methods) {
+				if (minfo.IsConstructor && minfo.AnyCustomAttributes (typeof (ExportAttribute))) {
 					if (minfo.IsStatic) {
 						// Diagnostic.Warning (log, "ExportAttribute does not work on static constructor");
 					}
@@ -278,8 +278,8 @@ static void ExtractJavaNames (string jniName, out string package, out string typ
 
 		void AddConstructors (TypeDefinition type, string? outerType, List<MethodDefinition>? baseCtors, List<MethodDefinition> curCtors, bool onlyRegisteredOrExportedCtors)
 		{
-			foreach (MethodDefinition ctor in type.Methods.Where (m => m.IsConstructor && !m.IsStatic))
-				if (!GetExportAttributes (ctor).Any ())
+			foreach (MethodDefinition ctor in type.Methods)
+				if (ctor.IsConstructor && !ctor.IsStatic && !ctor.AnyCustomAttributes (typeof (ExportAttribute)))
 					AddConstructor (ctor, type, outerType, baseCtors, curCtors, onlyRegisteredOrExportedCtors, false);
 		}
 
@@ -342,8 +342,7 @@ void AddConstructor (MethodDefinition ctor, TypeDefinition type, string? outerTy
 			while ((bmethod = method.GetBaseDefinition (cache)) != method) {
 				method = bmethod;
 
-				var attributes = method.GetCustomAttributes (typeof (RegisterAttribute));
-				if (attributes.Any ()) {
+				if (method.AnyCustomAttributes (typeof (RegisterAttribute))) {
 					return method;
 				}
 			}

src/Java.Interop.Tools.TypeNameMappings/Java.Interop.Tools.TypeNameMappings/JavaNativeTypeManager.cs

@@ -710,16 +710,24 @@ internal static bool IsNonStaticInnerClass (TypeDefinition? type, IMetadataResol
 			if (!type.DeclaringType.IsSubclassOf ("Java.Lang.Object", cache))
 				return false;
 
-			return GetBaseConstructors (type, cache)
-				.Any (ctor => ctor.Parameters.Any (p => p.Name == "__self"));
-		}
+			foreach (var baseType in type.GetBaseTypes (cache)) {
+				if (baseType == null)
+					continue;
+				if (!baseType.AnyCustomAttributes (typeof (RegisterAttribute)))
+					continue;
 
-		static IEnumerable<MethodDefinition> GetBaseConstructors (TypeDefinition type, IMetadataResolver cache)
-		{
-			var baseType = type.GetBaseTypes (cache).FirstOrDefault (t => t.GetCustomAttributes (typeof (RegisterAttribute)).Any ());
-			if (baseType != null)
-				return baseType.Methods.Where (m => m.IsConstructor && !m.IsStatic);
-			return Enumerable.Empty<MethodDefinition> ();
+				foreach (var method in baseType.Methods) {
+					if (!method.IsConstructor || method.IsStatic)
+						continue;
+					if (method.Parameters.Any (p => p.Name == "__self"))
+						return true;
+				}
+
+				// Stop at the first base type with [Register]
+				break;
+			}
+
+			return false;
 		}
 #endif  // HAVE_CECIL