Cache property type and field type on PropertyInfo/FieldInfo

Customer code was accessing the type of a cached property in a hot path. Always going back to metadata meant that we spent 20% of time resolving the property type.

I proactively applied the same fix to FieldInfo.

[tfs-changeset: 1689010]

2 files changed, 19 insertions, 3 deletions

diff --git a/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/FieldInfos/RuntimeFieldInfo.cs b/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/FieldInfos/RuntimeFieldInfo.cs
index 392f6db9e..31de164ab 100644
--- a/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/FieldInfos/RuntimeFieldInfo.cs
+++ b/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/FieldInfos/RuntimeFieldInfo.cs
@@ -89,7 +89,13 @@ namespace System.Reflection.Runtime.FieldInfos
         {
             get
             {
-                return this.FieldRuntimeType;
+                Type fieldType = _lazyFieldType;
+                if (fieldType == null)
+                {
+                    _lazyFieldType = fieldType = this.FieldRuntimeType;
+                }
+
+                return fieldType;
             }
         }
 
@@ -292,6 +298,8 @@ namespace System.Reflection.Runtime.FieldInfos
 
         private volatile FieldAccessor _lazyFieldAccessor = null;
 
+        private volatile Type _lazyFieldType = null;
+
         private String _debugName;
     }
 }
diff --git a/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/PropertyInfos/RuntimePropertyInfo.cs b/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/PropertyInfos/RuntimePropertyInfo.cs
index 7691902be..b8623f72c 100644
--- a/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/PropertyInfos/RuntimePropertyInfo.cs
+++ b/src/System.Private.Reflection.Core/src/System/Reflection/Runtime/PropertyInfos/RuntimePropertyInfo.cs
@@ -187,8 +187,14 @@ namespace System.Reflection.Runtime.PropertyInfos
                     ReflectionTrace.PropertyInfo_PropertyType(this);
 #endif
 
-                TypeContext typeContext = ContextTypeInfo.TypeContext;
-                return PropertyTypeHandle.Resolve(typeContext);
+                Type propertyType = _lazyPropertyType;
+                if (propertyType == null)
+                {
+                    TypeContext typeContext = ContextTypeInfo.TypeContext;
+                    _lazyPropertyType = propertyType = PropertyTypeHandle.Resolve(typeContext);
+                }
+
+                return propertyType;
             }
         }
 
@@ -402,6 +408,8 @@ namespace System.Reflection.Runtime.PropertyInfos
 
         private volatile ParameterInfo[] _lazyIndexParameters;
 
+        private volatile Type _lazyPropertyType;
+
         private String _debugName;
     }
 }