Use ref var to avoid field descriptor copying to stack and also to avoid repeating array indexing

Author: AlexUstinov

Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs

@@ -46,14 +46,15 @@ public override bool Equals(Tuple other)
       var fieldDescriptors = PackedDescriptor.FieldDescriptors;
       var count = Count;
       for (int i = 0; i < count; i++) {
-        var thisState = GetFieldState(ref fieldDescriptors[i]);
-        var otherState = packedOther.GetFieldState(ref fieldDescriptors[i]);
+        ref var descriptor = ref fieldDescriptors[i];
+        var thisState = GetFieldState(ref descriptor);
+        var otherState = packedOther.GetFieldState(ref descriptor);
         if (thisState!=otherState)
           return false;
         if (thisState!=TupleFieldState.Available)
           continue;
-        var accessor = fieldDescriptors[i].Accessor;
-        if (!accessor.ValueEquals(this, ref fieldDescriptors[i], packedOther, ref fieldDescriptors[i]))
+        var accessor = descriptor.Accessor;
+        if (!accessor.ValueEquals(this, ref descriptor, packedOther, ref descriptor))
           return false;
       }
 
@@ -66,10 +67,11 @@ public override int GetHashCode()
       var fieldDescriptors = PackedDescriptor.FieldDescriptors;
       int result = 0;
       for (int i = 0; i < count; i++) {
-        var accessor = fieldDescriptors[i].Accessor;
+        ref var descriptor = ref fieldDescriptors[i];
+        var accessor = descriptor.Accessor;
         var state = GetFieldState(ref fieldDescriptors[i]);
         var fieldHash = state==TupleFieldState.Available
-          ? accessor.GetValueHashCode(this, ref fieldDescriptors[i])
+          ? accessor.GetValueHashCode(this, ref descriptor)
           : 0;
         result = HashCodeMultiplier * result ^ fieldHash;
       }
@@ -83,23 +85,23 @@ public override TupleFieldState GetFieldState(int fieldIndex)
 
     protected internal override void SetFieldState(int fieldIndex, TupleFieldState fieldState)
     {
-      if (fieldState==TupleFieldState.Null)
-        throw new ArgumentOutOfRangeException("fieldState");
+      if (fieldState==TupleFieldState.Null) {
+        throw new ArgumentOutOfRangeException(nameof(fieldState));
+      }
 
-      var fieldDescriptors = PackedDescriptor.FieldDescriptors;
-      SetFieldState(ref fieldDescriptors[fieldIndex], fieldState);
+      SetFieldState(ref PackedDescriptor.FieldDescriptors[fieldIndex], fieldState);
     }
 
     public override object GetValue(int fieldIndex, out TupleFieldState fieldState)
     {
-      var fieldDescriptors = PackedDescriptor.FieldDescriptors;
-      return fieldDescriptors[fieldIndex].Accessor.GetUntypedValue(this, ref fieldDescriptors[fieldIndex], out fieldState);
+      ref var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
+      return descriptor.Accessor.GetUntypedValue(this, ref descriptor, out fieldState);
     }
 
     public override void SetValue(int fieldIndex, object fieldValue)
     {
-      var fieldDescriptors = PackedDescriptor.FieldDescriptors;
-      fieldDescriptors[fieldIndex].Accessor.SetUntypedValue(this, ref fieldDescriptors[fieldIndex], fieldValue);
+      ref var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
+      descriptor.Accessor.SetUntypedValue(this, ref descriptor, fieldValue);
     }
 
     public void SetFieldState(ref PackedFieldDescriptor d, TupleFieldState fieldState)

Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs

@@ -234,7 +234,12 @@ public static void Configure(Type[] fieldTypes, PackedFieldDescriptor[] fieldDes
       totalBitCount += prevCount;
 
       for (var fieldIndex = 0; fieldIndex < fieldCount; fieldIndex++) {
-        ConfigureFieldPhase2(ref fieldDescriptors[fieldIndex], ref counters);
+        ref var descriptor = ref fieldDescriptors[fieldIndex];
+        if (descriptor.IsObjectField) {
+          continue;
+        }
+
+        PositionUpdaterByRank[descriptor.Accessor.Rank].Invoke(ref descriptor, ref counters);
       }
 
       valuesLength = (totalBitCount + (Val064BitCount - 1)) >> Val064Rank;
@@ -268,16 +273,6 @@ private static void ConfigureFieldPhase1(ref PackedFieldDescriptor descriptor, r
       descriptor.DataPosition = counters.ObjectCounter++;
     }
 
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static void ConfigureFieldPhase2(ref PackedFieldDescriptor descriptor, ref Counters counters)
-    {
-      if (descriptor.IsObjectField) {
-        return;
-      }
-
-      PositionUpdaterByRank[descriptor.Accessor.Rank].Invoke(ref descriptor, ref counters);
-    }
-
     static TupleLayout()
     {
       IncrementerByRank = new CounterIncrementer[] {

Orm/Xtensive.Orm/Tuples/Tuple.cs

@@ -112,13 +112,13 @@ public T GetValue<T>(int fieldIndex, out TupleFieldState fieldState)
       var isNullable = null==default(T); // Is nullable value type or class
 
       if (this is PackedTuple packedTuple) {
-        var descriptor = packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
+        ref var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
         return descriptor.Accessor.GetValue<T>(packedTuple, ref descriptor, isNullable, out fieldState);
       }
 
       var mappedContainer = GetMappedContainer(fieldIndex, false);
       if (mappedContainer.First is PackedTuple mappedTuple) {
-        var descriptor = mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
+        ref var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
         return descriptor.Accessor.GetValue<T>(mappedTuple, ref descriptor, isNullable, out fieldState);
       }
 
@@ -187,14 +187,14 @@ public void SetValue<T>(int fieldIndex, T fieldValue)
       var isNullable = null==default(T); // Is nullable value type or class
 
       if (this is PackedTuple packedTuple) {
-        var descriptor = packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
+        ref var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
         descriptor.Accessor.SetValue(packedTuple, ref descriptor, isNullable, fieldValue);
         return;
       }
 
       var mappedContainer = GetMappedContainer(fieldIndex, true);
       if (mappedContainer.First is PackedTuple mappedTuple) {
-        var descriptor = mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
+        ref var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
         descriptor.Accessor.SetValue(mappedTuple, ref descriptor, isNullable, fieldValue);
         return;
       }

Orm/Xtensive.Orm/Tuples/TupleExtensions.cs

@@ -437,27 +437,29 @@ private static void CopyValue(Tuple source, int sourceIndex, Tuple target, int t
 
     private static void CopyPackedValue(PackedTuple source, int sourceIndex, PackedTuple target, int targetIndex)
     {
-      var sourceDescriptors = source.PackedDescriptor.FieldDescriptors;
-      var targetDescriptors = target.PackedDescriptor.FieldDescriptors;
+      ref var sourceDescriptor = ref source.PackedDescriptor.FieldDescriptors[sourceIndex];
+      ref var targetDescriptor = ref target.PackedDescriptor.FieldDescriptors[targetIndex];
 
-      var fieldState = source.GetFieldState(ref sourceDescriptors[sourceIndex]);
-      if (!fieldState.IsAvailable())
+      var fieldState = source.GetFieldState(ref sourceDescriptor);
+      if (!fieldState.IsAvailable()) {
         return;
+      }
 
       if (fieldState.IsAvailableAndNull()) {
         target.SetValue(targetIndex, null);
         return;
       }
 
-      var accessor = sourceDescriptors[sourceIndex].Accessor;
-      if (accessor!=targetDescriptors[targetIndex].Accessor)
+      var accessor = sourceDescriptor.Accessor;
+      if (accessor != targetDescriptor.Accessor) {
         throw new InvalidOperationException(string.Format(
           Strings.ExInvalidCast,
           source.PackedDescriptor[sourceIndex],
           target.PackedDescriptor[targetIndex]));
+      }
 
       target.SetFieldState(targetIndex, TupleFieldState.Available);
-      accessor.CopyValue(source, ref sourceDescriptors[sourceIndex], target, ref targetDescriptors[targetIndex]);
+      accessor.CopyValue(source, ref sourceDescriptor, target, ref targetDescriptor);
     }
 
     private static void PartiallyCopyTupleSlow(Tuple source, Tuple target, int sourceStartIndex, int targetStartIndex, int length)