Optimize size of PackedFieldDescriptor struct from 16 bytes to 8

Author: SergeiPavlov

Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs

@@ -1,4 +1,4 @@
-// Copyright (C) 2013-2021 Xtensive LLC.
+// Copyright (C) 2013-2022 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Denis Krjuchkov
@@ -10,6 +10,8 @@ namespace Xtensive.Tuples.Packed
 {
   internal abstract class PackedFieldAccessor
   {
+    public static readonly PackedFieldAccessor[] All = new PackedFieldAccessor[20];
+
     /// <summary>
     /// Getter delegate.
     /// </summary>
@@ -33,6 +35,7 @@ internal abstract class PackedFieldAccessor
     public readonly int Rank;
     public readonly int ValueBitCount;
     protected readonly long ValueBitMask;
+    public readonly byte Index;
 
     public void SetValue<T>(PackedTuple tuple, ref PackedFieldDescriptor descriptor, bool isNullable, T value)
     {
@@ -70,9 +73,14 @@ public abstract bool ValueEquals(PackedTuple left, ref PackedFieldDescriptor lef
 
     public abstract int GetValueHashCode(PackedTuple tuple, ref PackedFieldDescriptor descriptor);
 
-    protected PackedFieldAccessor(int rank)
+    protected PackedFieldAccessor(int rank, byte index)
     {
       Rank = rank;
+      Index = index;
+      if (All[Index] != null) {
+        throw new IndexOutOfRangeException($"Duplicated Index {Index} of PackedFieldAccessor instance");
+      }
+      All[Index] = this;
       ValueBitCount = 1 << Rank;
 
       // What we want here is to shift 1L by ValueBitCount to left and then subtract 1
@@ -128,7 +136,7 @@ public override int GetValueHashCode(PackedTuple tuple, ref PackedFieldDescripto
     }
 
     public ObjectFieldAccessor()
-      : base(-1)
+      : base(-1, 19)
     { }
   }
 
@@ -146,8 +154,8 @@ private static int GetRank(int bitSize)
       return rank;
     }
 
-    protected ValueFieldAccessor(int bitCount)
-      : base(GetRank(bitCount))
+    protected ValueFieldAccessor(int bitCount, byte index)
+      : base(GetRank(bitCount), index)
     {}
   }
 
@@ -255,8 +263,8 @@ private T Load(PackedTuple tuple, ref PackedFieldDescriptor d)
       return Decode(encoded);
     }
 
-    protected ValueFieldAccessor(int bits)
-      : base(bits)
+    protected ValueFieldAccessor(int bits, byte index)
+      : base(bits, index)
     {
       FieldType = typeof(T);
       Getter = (GetValueDelegate<T>) GetValue;
@@ -280,7 +288,7 @@ protected override bool Decode(long value)
     }
 
     public BooleanFieldAccessor()
-      : base(1)
+      : base(1, 1)
     {
     }
   }
@@ -303,7 +311,7 @@ protected override float Decode(long value)
     }
 
     public FloatFieldAccessor()
-      : base(sizeof(float) * 8)
+      : base(sizeof(float) * 8, 2)
     {
     }
   }
@@ -321,7 +329,7 @@ protected override double Decode(long value)
     }
 
     public DoubleFieldAccessor()
-      : base(sizeof(double) * 8)
+      : base(sizeof(double) * 8, 3)
     {
     }
   }
@@ -339,7 +347,7 @@ protected override TimeSpan Decode(long value)
     }
 
     public TimeSpanFieldAccessor()
-      : base(sizeof(long) * 8)
+      : base(sizeof(long) * 8, 4)
     {
     }
   }
@@ -357,7 +365,7 @@ protected override DateTime Decode(long value)
     }
 
     public DateTimeFieldAccessor()
-      : base(sizeof(long) * 8)
+      : base(sizeof(long) * 8, 5)
     {
     }
   }
@@ -375,7 +383,7 @@ protected override byte Decode(long value)
     }
 
     public ByteFieldAccessor()
-      : base(sizeof(byte) * 8)
+      : base(sizeof(byte) * 8, 6)
     {
     }
   }
@@ -393,7 +401,7 @@ protected override sbyte Decode(long value)
     }
 
     public SByteFieldAccessor()
-      : base(sizeof(sbyte) * 8)
+      : base(sizeof(sbyte) * 8, 7)
     {
     }
   }
@@ -411,7 +419,7 @@ protected override short Decode(long value)
     }
 
     public ShortFieldAccessor()
-      : base(sizeof(short) * 8)
+      : base(sizeof(short) * 8, 8)
     {
     }
   }
@@ -429,7 +437,7 @@ protected override ushort Decode(long value)
     }
 
     public UShortFieldAccessor()
-      : base(sizeof(ushort) * 8)
+      : base(sizeof(ushort) * 8, 9)
     {
     }
   }
@@ -447,7 +455,7 @@ protected override int Decode(long value)
     }
 
     public IntFieldAccessor()
-      : base(sizeof(int) * 8)
+      : base(sizeof(int) * 8, 10)
     {
     }
   }
@@ -465,7 +473,7 @@ protected override uint Decode(long value)
     }
 
     public UIntFieldAccessor()
-      : base(sizeof(uint) * 8)
+      : base(sizeof(uint) * 8, 11)
     {
     }
   }
@@ -483,7 +491,7 @@ protected override long Decode(long value)
     }
 
     public LongFieldAccessor()
-      : base(sizeof(long) * 8)
+      : base(sizeof(long) * 8, 12)
     {
     }
   }
@@ -501,7 +509,7 @@ protected override ulong Decode(long value)
     }
 
     public ULongFieldAccessor()
-      : base(sizeof(ulong) * 8)
+      : base(sizeof(ulong) * 8, 13)
     {
     }
   }
@@ -530,7 +538,7 @@ private static unsafe int GetSize()
     }
 
     public GuidFieldAccessor()
-      : base(GetSize() * 8)
+      : base(GetSize() * 8, 14)
     {
     }
   }
@@ -553,7 +561,7 @@ protected override void Encode(decimal value, long[] values, int offset)
       }
     }
     public DecimalFieldAccessor()
-      : base(sizeof(decimal) * 8)
+      : base(sizeof(decimal) * 8, 15)
     {
     }
   }
@@ -582,7 +590,7 @@ private static unsafe int GetSize()
     }
 
     public DateTimeOffsetFieldAccessor()
-       : base(GetSize() * 8)
+       : base(GetSize() * 8, 16)
     { }
   }
 }

Orm/Xtensive.Orm/Tuples/Packed/PackedFieldDescriptor.cs

@@ -1,6 +1,6 @@
-// Copyright (C) 2003-2012 Xtensive LLC.
-// All rights reserved.
-// For conditions of distribution and use, see license.
+// Copyright (C) 2003-2022 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
 // Created by: Denis Krjuchkov
 // Created:    2012.12.29
 
@@ -15,10 +15,12 @@ internal struct PackedFieldDescriptor
     private const int OffsetMask = (1 << OffsetBitCount) - 1;
 
     internal int DataPosition;
-    internal int StatePosition;
+    internal ushort StatePosition;
 
     [NonSerialized]
-    public PackedFieldAccessor Accessor;
+    internal byte AccessorIndex;
+
+    public PackedFieldAccessor Accessor => PackedFieldAccessor.All[AccessorIndex];
 
     public bool IsObjectField => Accessor.Rank < 0;
 

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

@@ -111,15 +111,15 @@ ValueFieldAccessor ResolveByNullableType(Type type)
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void ConfigureFieldAccessor(ref PackedFieldDescriptor descriptor, Type fieldType) =>
-      descriptor.Accessor = (PackedFieldAccessor) ValueFieldAccessorResolver.GetValue(fieldType) ?? ObjectAccessor;
+      descriptor.AccessorIndex = ((PackedFieldAccessor)ValueFieldAccessorResolver.GetValue(fieldType) ?? ObjectAccessor).Index;
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void ConfigureLen1(Type[] fieldTypes, ref PackedFieldDescriptor descriptor, out int valuesLength,
       out int objectsLength)
     {
       var valueAccessor = ValueFieldAccessorResolver.GetValue(fieldTypes[0]);
       if (valueAccessor != null) {
-        descriptor.Accessor = valueAccessor;
+        descriptor.AccessorIndex = valueAccessor.Index;
         descriptor.DataPosition = Val064BitCount;
 
         valuesLength = (valueAccessor.ValueBitCount  + ((Val064BitCount * 2) - 1)) >> Val064Rank;
@@ -128,7 +128,7 @@ public static void ConfigureLen1(Type[] fieldTypes, ref PackedFieldDescriptor de
         return;
       }
 
-      descriptor.Accessor = ObjectAccessor;
+      descriptor.AccessorIndex = ObjectAccessor.Index;
       valuesLength = 1;
       objectsLength = 1;
     }
@@ -234,19 +234,19 @@ private static void UpdateDescriptorPosition(ref PackedFieldDescriptor descripto
     private static void ConfigureFieldPhase1(ref PackedFieldDescriptor descriptor, ref Counters counters,
       Type[] fieldTypes, int fieldIndex)
     {
-      descriptor.StatePosition = fieldIndex << 1;
+      descriptor.StatePosition = checked((ushort)(fieldIndex << 1));
 
       var valueAccessor = ValueFieldAccessorResolver.GetValue(fieldTypes[fieldIndex]);
       if (valueAccessor != null) {
-        descriptor.Accessor = valueAccessor;
+        descriptor.AccessorIndex = valueAccessor.Index;
 
         IncrementerByRank[valueAccessor.Rank].Invoke(ref counters);
 
         fieldTypes[fieldIndex] = valueAccessor.FieldType;
         return;
       }
 
-      descriptor.Accessor = ObjectAccessor;
+      descriptor.AccessorIndex = ObjectAccessor.Index;
       descriptor.DataPosition = counters.ObjectCounter++;
     }