From 498282206e512e179f212eb254c2956c1471af5d Mon Sep 17 00:00:00 2001
From: Rolf Bjarne Kvinge <rolf@xamarin.com>
Date: Wed, 19 Oct 2016 11:29:44 +0200
Subject: [PATCH] [registrar] Cache the System.Void type.

Duration before: 1,60s
Duration after:  1,54s
Difference:     -0,06s = -3,8%

Memory usage hardly changed (-21 kb of 540 MB), but the number of method calls
shrunk significantly.

Method calls before: 86.720.379
Method calls after:  74.390.061
Difference:         -12.330.318 = -14,2%

The call to `GetSystemVoidType` was #2 on the list of method calls (whens
sorted by 'self'), called 1072 times taking 1429 ms each time. After this
change it's only called once (and obviously pushed way down the list).
---
 tools/common/StaticRegistrar.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/common/StaticRegistrar.cs b/tools/common/StaticRegistrar.cs
index 57f3aec8b1ee..6008101b3c00 100644
--- a/tools/common/StaticRegistrar.cs
+++ b/tools/common/StaticRegistrar.cs
@@ -827,8 +827,12 @@ protected override TypeReference GetReturnType (MethodDefinition method)
 			return method.ReturnType;
 		}
 
+		TypeReference system_void;
 		protected override TypeReference GetSystemVoidType ()
 		{
+			if (system_void != null)
+				return system_void;
+			
 			// find corlib
 			AssemblyDefinition corlib = null;
 			AssemblyDefinition first = null;
@@ -847,7 +851,7 @@ protected override TypeReference GetSystemVoidType ()
 			}
 			foreach (var type in corlib.MainModule.Types) {
 				if (type.Namespace == "System" && type.Name == "Void")
-					return type;
+					return system_void = type;
 			}
 
 			throw new Exception ("Couldn't find System.Void");