Don't create interator parameters copies for unmodified parameters

4 files changed, 64 insertions, 47 deletions

diff --git a/mcs/mcs/anonymous.cs b/mcs/mcs/anonymous.cs
index fe16344ae0d..7b7ba0b5322 100644
--- a/mcs/mcs/anonymous.cs
+++ b/mcs/mcs/anonymous.cs
@@ -569,6 +569,9 @@ namespace Mono.CSharp {
 		protected virtual void EmitHoistedParameters (EmitContext ec, List<HoistedParameter> hoisted)
 		{
 			foreach (HoistedParameter hp in hoisted) {
+				if (hp == null)
+					continue;
+
 				//
 				// Parameters could be proxied via local fields for value type storey
 				//
@@ -851,6 +854,8 @@ namespace Mono.CSharp {
 			}
 		}
 
+		public bool IsAssigned { get; set; }
+
 		public ParameterReference Parameter {
 			get {
 				return parameter;
diff --git a/mcs/mcs/expression.cs b/mcs/mcs/expression.cs
index a43e4ab7dc8..5047b891a4e 100644
--- a/mcs/mcs/expression.cs
+++ b/mcs/mcs/expression.cs
@@ -5184,6 +5184,9 @@ namespace Mono.CSharp
 
 		void SetAssigned (ResolveContext ec)
 		{
+			if (Parameter.HoistedVariant != null)
+				Parameter.HoistedVariant.IsAssigned = true;
+
 			if (HasOutModifier && ec.DoFlowAnalysis)
 				ec.CurrentBranching.SetAssigned (VariableInfo);
 		}
diff --git a/mcs/mcs/iterators.cs b/mcs/mcs/iterators.cs
index 80fb71d8267..bb7d4ab86f1 100644
--- a/mcs/mcs/iterators.cs
+++ b/mcs/mcs/iterators.cs
@@ -245,7 +245,7 @@ namespace Mono.CSharp
 
 						for (int i = 0; i < host.hoisted_params.Count; ++i) {
 							HoistedParameter hp = host.hoisted_params [i];
-							HoistedParameter hp_cp = host.hoisted_params_copy [i];
+							HoistedParameter hp_cp = host.hoisted_params_copy [i] ?? hp;
 
 							FieldExpr from = new FieldExpr (hp_cp.Field, loc);
 							from.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
@@ -482,11 +482,20 @@ namespace Mono.CSharp
 				// create same enumerator therefore we have to keep original values
 				// around for re-initialization
 				//
-				// TODO: Do it for assigned/modified parameters only
-				//
 				hoisted_params_copy = new List<HoistedParameter> (hoisted_params.Count);
 				foreach (HoistedParameter hp in hoisted_params) {
-					hoisted_params_copy.Add (new HoistedParameter (hp, "<$>" + hp.Field.Name));
+
+					//
+					// Don't create field copy for unmodified captured parameters
+ 					//
+					HoistedParameter hp_copy;
+					if (hp.IsAssigned) {
+						hp_copy = new HoistedParameter (hp, "<$>" + hp.Field.Name);
+					} else {
+						hp_copy = null;
+					}
+
+					hoisted_params_copy.Add (hp_copy);
 				}
 			}
 
diff --git a/mcs/tests/ver-il-net_4_5.xml b/mcs/tests/ver-il-net_4_5.xml
index e23c9f307b1..b41bd8cf779 100644
--- a/mcs/tests/ver-il-net_4_5.xml
+++ b/mcs/tests/ver-il-net_4_5.xml
@@ -4888,7 +4888,7 @@
   <test name="gtest-062.cs">

     <type name="X">

       <method name="IEnumerable`1 Test(Int32, Int64)" attrs="134">

-        <size>51</size>

+        <size>44</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>95</size>

@@ -7980,7 +7980,7 @@
         <size>2</size>

       </method>

       <method name="IEnumerable get_Item(Int32)" attrs="2177">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void set_Item(Int32, IEnumerable)" attrs="2177">

         <size>2</size>

@@ -8063,7 +8063,7 @@
   <test name="gtest-183.cs">

     <type name="test.Test`1[T]">

       <method name="IEnumerable`1 Lookup(T)" attrs="134">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -8299,7 +8299,7 @@
     </type>

     <type name="Test5.Test">

       <method name="IEnumerable`1 Replace[T](T)" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -8307,7 +8307,7 @@
     </type>

     <type name="Test6.Test">

       <method name="IEnumerable`1 Replace[T](T)" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -8315,7 +8315,7 @@
     </type>

     <type name="Test7.Test">

       <method name="IEnumerable`1 Replace[T](T[])" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -9229,10 +9229,10 @@
         <size>99</size>

       </method>

       <method name="IEnumerable`1 Map[Aa,Af,Rf,Rr](Fun`2[Af,Rf], IEnumerable`1)" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="IEnumerable`1 FromTo(Int32, Int32)" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="System.String &lt;Main&gt;m__0(Int32)" attrs="145">

         <size>22</size>

@@ -18440,7 +18440,7 @@
   <test name="gtest-anontype-13.cs">

     <type name="Test">

       <method name="IEnumerable`1 Select[T](System.Array, System.Func`2[System.Object,T])" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>182</size>

@@ -20252,7 +20252,7 @@
         <size>66</size>

       </method>

       <method name="IEnumerable`1 Test[T](Int32)" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -20307,7 +20307,7 @@
         <size>67</size>

       </method>

       <method name="IEnumerable`1 GetPersons[T](IEnumerable`1, Int32)" attrs="145">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Boolean Test[T](T, System.Linq.Expressions.Expression`1[System.Func`2[T,System.Boolean]])" attrs="145">

         <size>21</size>

@@ -22159,7 +22159,7 @@
         <size>30</size>

       </method>

       <method name="IEnumerable`1 Annotations(System.Type)" attrs="134">

-        <size>44</size>

+        <size>37</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>15</size>

@@ -22277,7 +22277,7 @@
         <size>32</size>

       </method>

       <method name="IEnumerable`1 TestRoutine[T](IEnumerable`1, Foo`1[T])" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -22329,7 +22329,7 @@
         <size>16</size>

       </method>

       <method name="IEnumerable`1 CreateUnfoldrIterator[TSource,TResult](TSource, System.Func`2[TSource,System.Nullable`1[System.Collections.Generic.KeyValuePair`2[TResult,TSource]]])" attrs="145">

-        <size>51</size>

+        <size>44</size>

       </method>

     </type>

     <type name="Mono.Rocks.Test">

@@ -22465,7 +22465,7 @@
   <test name="gtest-iter-09.cs">

     <type name="Test">

       <method name="IEnumerable`1 Create[T](T[,])" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>89</size>

@@ -22504,7 +22504,7 @@
   <test name="gtest-iter-10.cs">

     <type name="Test">

       <method name="IEnumerable`1 FromTo(Int32, Int32)" attrs="145">

-        <size>51</size>

+        <size>44</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>185</size>

@@ -22611,7 +22611,7 @@
         <size>2</size>

       </method>

       <method name="IEnumerable`1 Merge[T](IEnumerator`1)" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -22650,7 +22650,7 @@
         <size>20</size>

       </method>

       <method name="IEnumerable`1 Filter(System.Func`2[T,System.Boolean])" attrs="134">

-        <size>44</size>

+        <size>37</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -22795,7 +22795,7 @@
   <test name="gtest-iter-15.cs">

     <type name="C`1[TFirst]">

       <method name="IEnumerable`1 GetEnumerable[V](IEnumerable`1)" attrs="131">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -22852,7 +22852,7 @@
     </type>

     <type name="Test.Derived">

       <method name="IEnumerable`1 GetStuff(Int32)" attrs="198">

-        <size>44</size>

+        <size>37</size>

       </method>

       <method name="IEnumerable`1 &lt;GetStuff&gt;__BaseCallProxy0(Int32)" attrs="129">

         <size>15</size>

@@ -22863,7 +22863,7 @@
     </type>

     <type name="Test.SpecialDerived">

       <method name="IEnumerable`1 GetStuff(Int32)" attrs="198">

-        <size>44</size>

+        <size>37</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>65</size>

@@ -23035,7 +23035,7 @@
   <test name="gtest-iter-19.cs">

     <type name="IEnumerableTransform">

       <method name="IEnumerable`1 Transform[TOut](IEnumerable`1, IEnumerableTransform+EmitterFunc`1[TOut])" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="IEnumerableTransform+EmitterFunc`1[TOut] Emit[TOut](TOut)" attrs="150">

         <size>34</size>

@@ -23494,7 +23494,7 @@
   <test name="gtest-iter-28.cs">

     <type name="A">

       <method name="IEnumerable`1 Test(B)" attrs="134">

-        <size>44</size>

+        <size>37</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>18</size>

@@ -25777,7 +25777,7 @@
     </type>

     <type name="NameCollisionTest.Ex">

       <method name="IEnumerable`1 Foo[T,TR](IEnumerable`1, System.Func`2[T,TR])" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

     </type>

     <type name="NameCollisionTest.C">

@@ -47592,7 +47592,7 @@
     </type>

     <type name="Foo">

       <method name="IEnumerable`1 Test(Foo)" attrs="134">

-        <size>49</size>

+        <size>42</size>

       </method>

       <method name="Void Hello(Int32)" attrs="134">

         <size>20</size>

@@ -47694,7 +47694,7 @@
     </type>

     <type name="X">

       <method name="IEnumerable`1 Test(Int32)" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>62</size>

@@ -47793,7 +47793,7 @@
         <size>38</size>

       </method>

       <method name="IEnumerable`1 op_Addition(Test, Test)" attrs="2198">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="IEnumerable`1 get_Foo()" attrs="2182">

         <size>23</size>

@@ -47931,7 +47931,7 @@
   <test name="test-anon-110.cs">

     <type name="X">

       <method name="IEnumerable`1 Test[T](T, T)" attrs="134">

-        <size>51</size>

+        <size>44</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>110</size>

@@ -52021,7 +52021,7 @@
   <test name="test-anon-50.cs">

     <type name="Test">

       <method name="IEnumerable Foo(Int32)" attrs="134">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -57268,7 +57268,7 @@
   <test name="test-async-30.cs">

     <type name="C">

       <method name="IEnumerable`1 Test(System.String)" attrs="129">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="IEnumerable`1 Test2()" attrs="129">

         <size>23</size>

@@ -59477,10 +59477,10 @@
   <test name="test-iter-03.cs">

     <type name="X">

       <method name="IEnumerable GetIt(System.Int32[])" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="IEnumerable GetMulti(System.Int32[,])" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>275</size>

@@ -59545,7 +59545,7 @@
   <test name="test-iter-04.cs">

     <type name="X">

       <method name="IEnumerable GetRange(Int32, Int32)" attrs="145">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>104</size>

@@ -59651,18 +59651,18 @@
   <test name="test-iter-06.cs">

     <type name="S">

       <method name="IEnumerable Get(Int32)" attrs="134">

-        <size>49</size>

+        <size>42</size>

       </method>

       <method name="IEnumerable GetS(Int32)" attrs="150">

-        <size>37</size>

+        <size>30</size>

       </method>

     </type>

     <type name="X">

       <method name="IEnumerable Get(Int32)" attrs="129">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="IEnumerable GetS(Int32)" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>449</size>

@@ -59779,7 +59779,7 @@
   <test name="test-iter-07.cs">

     <type name="Test">

       <method name="IEnumerable Foo(Int32)" attrs="134">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -59840,7 +59840,7 @@
     </type>

     <type name="X">

       <method name="IEnumerable Test(Int32, Int32)" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>210</size>

@@ -59926,7 +59926,7 @@
         <size>2</size>

       </method>

       <method name="IEnumerable get_Item(Int32)" attrs="2177">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void set_Item(Int32, IEnumerable)" attrs="2177">

         <size>2</size>

@@ -60278,7 +60278,7 @@
   <test name="test-iter-18.cs">

     <type name="test">

       <method name="IEnumerable testen(Int32)" attrs="134">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Void .ctor()" attrs="6278">

         <size>7</size>

@@ -60393,7 +60393,7 @@
   <test name="test-iter-21.cs">

     <type name="X">

       <method name="IEnumerable GetIt(System.Int32[])" attrs="145">

-        <size>37</size>

+        <size>30</size>

       </method>

       <method name="Int32 Main()" attrs="150">

         <size>138</size>

@@ -60598,7 +60598,7 @@
   <test name="test-iter-26.cs">

     <type name="C">

       <method name="IEnumerable Test(Boolean, Int32)" attrs="150">

-        <size>51</size>

+        <size>37</size>

       </method>

       <method name="Void Main()" attrs="150">

         <size>10</size>