[jnimarshalmethod-gen] Fix type resolution crash (#706)

The TypeMover was crashing, when we cannot resolve the type during
register method optimization.

Like this:

    Value cannot be null.
    Parameter name: key
    System.ArgumentNullException: Value cannot be null.
    Parameter name: key
      at System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) [0x00175] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/debug/external/corefx/src/Common/src/CoreLib/System/Collections/Generic/Dictionary.cs:470
      at System.Collections.Generic.Dictionary`2[TKey,TValue].ContainsKey (TKey key) [0x00000] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/debug/external/corefx/src/Common/src/CoreLib/System/Collections/Generic/Dictionary.cs:286
      at Xamarin.Android.Tools.JniMarshalMethodGenerator.TypeMover.Resolve (Mono.Cecil.TypeReference type) [0x00001] in /Users/rodo/git/xa-clean/external/Java.Interop/tools/jnimarshalmethod-gen/TypeMover.cs:143
      at Xamarin.Android.Tools.JniMarshalMethodGenerator.TypeMover.GetActionConstructor (Mono.Cecil.TypeReference type, Mono.Cecil.ModuleDefinition module) [0x00012] in /Users/rodo/git/xa-clean/external/Java.Interop/tools/jnimarshalmethod-gen/TypeMover.cs:335
      at Xamarin.Android.Tools.JniMarshalMethodGenerator.TypeMover.AnalyzeAndImprove (Mono.Collections.Generic.Collection`1[T] instructions, Mono.Collections.Generic.Collection`1[T] newInstructions, System.Int32 idx, System.String typeName, System.Int32& skipCount, Mono.Cecil.ModuleDefinition module) [0x003b6] in /Users/rodo/git/xa-clean/external/Java.Interop/tools/jnimarshalmethod-gen/TypeMover.cs:417

The tool was crashing on IL like this:

    IL_0122:  ldstr      "Delegate18$1"
    IL_0127:  ldc.i4.1
    IL_0128:  call       [mscorlib]System.Type [mscorlib]System.Type::GetType(string,
                                                                              bool)

The fix makes us more error resistant. It doesn't fix the source of the problem,
which will be fixed elsewhere.

More information about the issue which led to the crash: #709

Author: radekdoulik

tools/jnimarshalmethod-gen/TypeMover.cs

@@ -15,6 +15,7 @@ public class TypeMover
 		AssemblyDefinition Destination { get; }
 		string DestinationPath { get; }
 		Dictionary<string, System.Reflection.Emit.TypeBuilder> Types { get; }
+		DirectoryAssemblyResolver Resolver { get; }
 
 		MethodReference consoleWriteLine;
 		TypeDefinitionCache cache;
@@ -25,10 +26,11 @@ public TypeMover (AssemblyDefinition source, AssemblyDefinition destination, str
 			Destination = destination;
 			DestinationPath = destinationPath;
 			Types = types;
+			Resolver = resolver;
 			this.cache = cache;
 
 			if (App.Debug) {
-				consoleWriteLine = GetSingleParameterMethod (resolver, Destination.MainModule, "mscorlib", "System.Console", "WriteLine", "System.String");
+				consoleWriteLine = GetSingleParameterMethod (Destination.MainModule, "mscorlib", "System.Console", "WriteLine", "System.String");
 				if (consoleWriteLine == null) {
 					App.Warning (Message.WarningUnableToFindSCWriteLine);
 					App.Debug = false;
@@ -400,6 +402,15 @@ bool AnalyzeAndImprove (Mono.Collections.Generic.Collection<Instruction> instruc
 						return false;
 
 					delegateType = module.GetType (delegateTypeName);
+					if (delegateType == null) {
+						var t = Type.GetType (delegateTypeName);
+						if (t == null)
+							return false;
+
+						delegateType = GetType (t.Assembly.GetName ().ToString (), delegateTypeName);
+						if (delegateType == null)
+							return false;
+					}
 
 					skipCount = 11;
 					customDelegate = true;
@@ -516,16 +527,18 @@ MethodDefinition Duplicate (MethodDefinition src, ModuleDefinition module, TypeD
 			return md;
 		}
 
-		MethodReference GetSingleParameterMethod (DirectoryAssemblyResolver resolver, ModuleDefinition module, string assemblyName, string typeName, string methodName, string parameterTypeName)
+		TypeDefinition GetType (string assemblyName, string typeName)
 		{
-			var assembly = resolver.Resolve (assemblyName);
+			var assembly = Resolver.Resolve (assemblyName);
 			if (assembly == null)
 				return null;
 
-			var typeTD = assembly.MainModule.GetType (typeName);
-			if (typeTD == null)
-				return null;
+			return assembly.MainModule.GetType (typeName);
+		}
 
+		MethodReference GetSingleParameterMethod (ModuleDefinition module, string assemblyName, string typeName, string methodName, string parameterTypeName)
+		{
+			var typeTD = GetType (assemblyName, typeName);
 			foreach (var md in typeTD.Methods)
 				if (md.Name == methodName && md.HasParameters && md.Parameters.Count == 1 && md.Parameters [0].ParameterType.FullName == parameterTypeName)
 					return GetUpdatedMethod (md, module);