[WIP] Actual code generator

Squash everything into a single commit, for easier rebasing
on the `marshal-methods-generator` branch

Author: grendello

src/Xamarin.Android.Build.Tasks/Tasks/GenerateJavaStubs.cs

@@ -237,6 +237,7 @@ void Run (DirectoryAssemblyResolver res)
 					string managedKey = type.FullName.Replace ('/', '.');
 					string javaKey = JavaNativeTypeManager.ToJniName (type, cache).Replace ('/', '.');
 
+					Console.WriteLine ($"##G2: {type.FullName} -> {javaKey}");
 					acw_map.Write (type.GetPartialAssemblyQualifiedName (cache));
 					acw_map.Write (';');
 					acw_map.Write (javaKey);
@@ -384,6 +385,7 @@ bool CreateJavaSources (IEnumerable<TypeDefinition> javaTypes, TypeDefinitionCac
 
 			bool ok = true;
 			foreach (var t in javaTypes) {
+				Console.WriteLine ($"##G0: JCW for {t.FullName}");
 				if (t.IsInterface) {
 					// Interfaces are in typemap but they shouldn't have JCW generated for them
 					continue;

src/Xamarin.Android.Build.Tasks/Utilities/LlvmIrGenerator/Arm32LlvmIrGenerator.cs

@@ -16,6 +16,12 @@ class Arm32LlvmIrGenerator : LlvmIrGenerator
 		public override int PointerSize   => 4;
 		protected override string Triple     => "armv7-unknown-linux-android"; // NDK appends API level, we don't need that
 
+		static readonly LlvmFunctionAttributeSet commonAttributes = new LlvmFunctionAttributeSet {
+			new FramePointerFunctionAttribute ("all"),
+			new TargetCpuFunctionAttribute ("generic"),
+			new TargetFeaturesFunctionAttribute ("+armv7-a,+d32,+dsp,+fp64,+neon,+thumb-mode,+vfp2,+vfp2sp,+vfp3,+vfp3d16,+vfp3d16sp,+vfp3sp,-aes,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fullfp16,-sha2,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp"),
+		};
+
 		public Arm32LlvmIrGenerator (AndroidTargetArch arch, StreamWriter output, string fileName)
 			: base (arch, output, fileName)
 		{}
@@ -25,5 +31,13 @@ protected override void AddModuleFlagsMetadata (List<LlvmIrMetadataItem> flagsFi
 			base.AddModuleFlagsMetadata (flagsFields);
 			flagsFields.Add (MetadataManager.AddNumbered (LlvmIrModuleMergeBehavior.Error, "min_enum_size", 4));
 		}
+
+		protected override void InitFunctionAttributes ()
+		{
+			base.InitFunctionAttributes ();
+
+			FunctionAttributes[FunctionAttributesXamarinAppInit].Add (commonAttributes);
+			FunctionAttributes[FunctionAttributesJniMethods].Add (commonAttributes);
+		}
 	}
 }

src/Xamarin.Android.Build.Tasks/Utilities/LlvmIrGenerator/Arm64LlvmIrGenerator.cs

@@ -16,6 +16,12 @@ class Arm64LlvmIrGenerator : LlvmIrGenerator
 		public override int PointerSize   => 8;
 		protected override string Triple     => "aarch64-unknown-linux-android"; // NDK appends API level, we don't need that
 
+		static readonly LlvmFunctionAttributeSet commonAttributes = new LlvmFunctionAttributeSet {
+			new FramePointerFunctionAttribute ("non-leaf"),
+			new TargetCpuFunctionAttribute ("generic"),
+			new TargetFeaturesFunctionAttribute ("+neon,+outline-atomics"),
+		};
+
 		public Arm64LlvmIrGenerator (AndroidTargetArch arch, StreamWriter output, string fileName)
 			: base (arch, output, fileName)
 		{}
@@ -29,5 +35,13 @@ protected override void AddModuleFlagsMetadata (List<LlvmIrMetadataItem> flagsFi
 			flagsFields.Add (MetadataManager.AddNumbered (LlvmIrModuleMergeBehavior.Error, "sign-return-address-all", 0));
 			flagsFields.Add (MetadataManager.AddNumbered (LlvmIrModuleMergeBehavior.Error, "sign-return-address-with-bkey", 0));
 		}
+
+		protected override void InitFunctionAttributes ()
+		{
+			base.InitFunctionAttributes ();
+
+			FunctionAttributes[FunctionAttributesXamarinAppInit].Add (commonAttributes);
+			FunctionAttributes[FunctionAttributesJniMethods].Add (commonAttributes);
+		}
 	}
 }