Implement automatic handling of the HasFieldRVA field attribute. (jbevain#733)

* Implement automatic handling of the HasFieldRVA field attribute.

Fixes jbevain#728

* Add FieldDefinition.HasFieldRVA

Co-authored-by: Jb Evain <jb@evain.net>

Author: jkoritzinsky

Mono.Cecil/FieldDefinition.cs

@@ -113,6 +113,7 @@ public byte [] InitialValue {
 			}
 			set {
 				initial_value = value;
+				HasFieldRVA = !initial_value.IsNullOrEmpty ();
 				rva = 0;
 			}
 		}
@@ -245,6 +246,11 @@ public bool HasDefault {
 			set { attributes = attributes.SetAttributes ((ushort) FieldAttributes.HasDefault, value); }
 		}
 
+		public bool HasFieldRVA {
+			get { return attributes.GetAttributes ((ushort) FieldAttributes.HasFieldRVA); }
+			set { attributes = attributes.SetAttributes ((ushort) FieldAttributes.HasFieldRVA, value); }
+		}
+
 		#endregion
 
 		public override bool IsDefinition {

Test/Mono.Cecil.Tests/FieldTests.cs

@@ -122,6 +122,14 @@ public void FieldRVA ()
 				Assert.AreEqual (2, buffer.ReadUInt32 ());
 				Assert.AreEqual (3, buffer.ReadUInt32 ());
 				Assert.AreEqual (4, buffer.ReadUInt32 ());
+
+				var intialValue = field.InitialValue;
+				field.InitialValue = null;
+				Assert.False (field.Attributes.HasFlag (FieldAttributes.HasFieldRVA));
+
+				field.InitialValue = intialValue;
+
+				Assert.True (field.Attributes.HasFlag (FieldAttributes.HasFieldRVA));
 			});
 		}