From c48633571a0bd24ae0cb3184490defe67a91a192 Mon Sep 17 00:00:00 2001
From: jfrijters <jfrijters>
Date: Fri, 26 Jun 2015 11:22:19 +0000
Subject: Moved unused field removal optimization to a later stage in the
 compilation. Also made the check more strict to only remove final fields and
 not remove fields that have annotations.

---
 ikvmc/Compiler.cs             |  2 +-
 ikvmc/CompilerClassLoader.cs  |  5 -----
 runtime/ClassFile.cs          | 20 +-------------------
 runtime/ClassLoaderWrapper.cs |  9 +++++++++
 runtime/DynamicTypeWrapper.cs | 12 ++++++++++++
 5 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/ikvmc/Compiler.cs b/ikvmc/Compiler.cs
index 659d4751..159052cd 100644
--- a/ikvmc/Compiler.cs
+++ b/ikvmc/Compiler.cs
@@ -838,7 +838,7 @@ sealed class IkvmcCompiler
 				}
 				else if(s == "-opt:fields")
 				{
-					options.removeUnusedFields = true;
+					options.codegenoptions |= CodeGenOptions.RemoveUnusedFields;
 				}
 				else if(s == "-compressresources")
 				{
diff --git a/ikvmc/CompilerClassLoader.cs b/ikvmc/CompilerClassLoader.cs
index 8bae21a2..1d6e66a3 100644
--- a/ikvmc/CompilerClassLoader.cs
+++ b/ikvmc/CompilerClassLoader.cs
@@ -294,10 +294,6 @@ namespace IKVM.Internal
 						StaticCompiler.IssueMessage(options, Message.WrongClassName, name, f.Name);
 						return null;
 					}
-					if(options.removeUnusedFields)
-					{
-						f.RemoveUnusedFields();
-					}
 					if(f.IsPublic && options.privatePackages != null)
 					{
 						foreach(string p in options.privatePackages)
@@ -3475,7 +3471,6 @@ namespace IKVM.Internal
 		internal Dictionary<string, string> props;
 		internal bool noglobbing;
 		internal CodeGenOptions codegenoptions;
-		internal bool removeUnusedFields;
 		internal bool compressedResources;
 		internal string[] privatePackages;
 		internal string[] publicPackages;
diff --git a/runtime/ClassFile.cs b/runtime/ClassFile.cs
index 9dfa170f..8eeb2e85 100644
--- a/runtime/ClassFile.cs
+++ b/runtime/ClassFile.cs
@@ -1037,25 +1037,7 @@ namespace IKVM.Internal
 			}
 		}
 
-		internal void RemoveUnusedFields()
-		{
-			List<Field> list = new List<Field>();
-			foreach(Field f in fields)
-			{
-				if(f.IsPrivate && f.IsStatic && f.Name != "serialVersionUID" && !IsReferenced(f))
-				{
-					// unused, so we skip it
-					Tracer.Info(Tracer.Compiler, "Unused field {0}::{1}", this.Name, f.Name);
-				}
-				else
-				{
-					list.Add(f);
-				}
-			}
-			fields = list.ToArray();
-		}
-
-		private bool IsReferenced(Field fld)
+		internal bool IsReferenced(Field fld)
 		{
 			foreach(ConstantPoolItem cpi in constantpool)
 			{
diff --git a/runtime/ClassLoaderWrapper.cs b/runtime/ClassLoaderWrapper.cs
index a7907db2..48a60068 100644
--- a/runtime/ClassLoaderWrapper.cs
+++ b/runtime/ClassLoaderWrapper.cs
@@ -53,6 +53,7 @@ namespace IKVM.Internal
 		NoAutomagicSerialization = 32,
 		DisableDynamicBinding = 64,
 		NoRefEmitHelpers = 128,
+		RemoveUnusedFields = 256,
 	}
 
 	[Flags]
@@ -329,6 +330,14 @@ namespace IKVM.Internal
 			}
 		}
 
+		internal bool RemoveUnusedFields
+		{
+			get
+			{
+				return (codegenoptions & CodeGenOptions.RemoveUnusedFields) != 0;
+			}
+		}
+
 		internal bool WorkaroundAbstractMethodWidening
 		{
 			get
diff --git a/runtime/DynamicTypeWrapper.cs b/runtime/DynamicTypeWrapper.cs
index a1d89318..ca89df7f 100644
--- a/runtime/DynamicTypeWrapper.cs
+++ b/runtime/DynamicTypeWrapper.cs
@@ -1520,6 +1520,18 @@ namespace IKVM.Internal
 				}
 				int fieldIndex = GetFieldIndex(fw);
 #if STATIC_COMPILER
+				if (wrapper.GetClassLoader().RemoveUnusedFields
+					&& fw.IsPrivate
+					&& fw.IsStatic
+					&& fw.IsFinal
+					&& fw.Name != "serialVersionUID"
+					&& classFile.Fields[fieldIndex].Annotations == null
+					&& !classFile.IsReferenced(classFile.Fields[fieldIndex]))
+				{
+					// unused, so we skip it
+					Tracer.Info(Tracer.Compiler, "Unused field {0}::{1}", wrapper.Name, fw.Name);
+					return null;
+				}
 				// for compatibility with broken Java code that assumes that reflection returns the fields in class declaration
 				// order, we emit the fields in class declaration order in the .NET metadata (and then when we retrieve them
 				// using .NET reflection, we sort on metadata token.)
-- 
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