Avoid some allocations during loading.

- In FieldLoader, cache boxed bools and some boxed ints.
- In FieldLoader, presize collections when parsing a List, HashSet or Dictionary.
- In FieldLoader, don't allocate a list of missing items until required.
- In FieldLoader, when a string value is passed, avoid wrapping this in a MiniYaml object by allowing both strings and yaml to be passed in the GetValue overload that does the real work.
- In Animation, avoid allocating no-op actions.
- In VxlReader, use EnsureCapcity to better size the Dictionary.
- In VxlReader change VxlElement to a struct.
- In Locomotor, presize TerrainSpeeds dictionary.

OpenRA.Game/FieldLoader.cs

@@ -112,10 +112,19 @@ namespace OpenRA
 				{ typeof(Nullable<>), ParseNullable },
 			};
 
+		static readonly object BoxedTrue = true;
+		static readonly object BoxedFalse = false;
+		static readonly object[] BoxedInts = Exts.MakeArray(33, i => (object)i);
+
 		static object ParseInt(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (Exts.TryParseIntegerInvariant(value, out var res))
+			{
+				if (res >= 0 && res < BoxedInts.Length)
+					return BoxedInts[res];
 				return res;
+			}
+
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
 
@@ -361,7 +370,7 @@ namespace OpenRA
 		static object ParseBool(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
 			if (bool.TryParse(value.ToLowerInvariant(), out var result))
-				return result;
+				return result ? BoxedTrue : BoxedFalse;
 
 			return InvalidValueAction(value, fieldType, fieldName);
 		}
@@ -469,11 +478,11 @@ namespace OpenRA
 
 		static object ParseHashSetOrList(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
-			var set = Activator.CreateInstance(fieldType);
 			if (value == null)
-				return set;
+				return Activator.CreateInstance(fieldType);
 
 			var parts = value.Split(SplitComma, StringSplitOptions.RemoveEmptyEntries);
+			var set = Activator.CreateInstance(fieldType, parts.Length);
 			var arguments = fieldType.GetGenericArguments();
 			var addMethod = fieldType.GetMethod(nameof(List<object>.Add), arguments);
 			var addArgs = new object[1];
@@ -488,7 +497,10 @@ namespace OpenRA
 
 		static object ParseDictionary(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
 		{
-			var dict = Activator.CreateInstance(fieldType);
+			if (yaml == null)
+				return Activator.CreateInstance(fieldType);
+
+			var dict = Activator.CreateInstance(fieldType, yaml.Nodes.Count);
 			var arguments = fieldType.GetGenericArguments();
 			var addMethod = fieldType.GetMethod(nameof(Dictionary<object, object>.Add), arguments);
 			var addArgs = new object[2];
@@ -527,7 +539,7 @@ namespace OpenRA
 		public static void Load(object self, MiniYaml my)
 		{
 			var loadInfo = TypeLoadInfo[self.GetType()];
-			var missing = new List<string>();
+			List<string> missing = null;
 
 			Dictionary<string, MiniYaml> md = null;
 
@@ -542,6 +554,7 @@ namespace OpenRA
 						val = fli.Loader(my);
 					else
 					{
+						missing ??= new List<string>();
 						missing.Add(fli.YamlName);
 						continue;
 					}
@@ -551,7 +564,11 @@ namespace OpenRA
 					if (!TryGetValueFromYaml(fli.YamlName, fli.Field, md, out val))
 					{
 						if (fli.Attribute.Required)
+						{
+							missing ??= new List<string>();
 							missing.Add(fli.YamlName);
+						}
+
 						continue;
 					}
 				}
@@ -559,7 +576,7 @@ namespace OpenRA
 				fli.Field.SetValue(self, val);
 			}
 
-			if (missing.Count > 0)
+			if (missing != null)
 				throw new MissingFieldsException(missing.ToArray());
 		}
 
@@ -620,12 +637,17 @@ namespace OpenRA
 
 		public static object GetValue(string fieldName, Type fieldType, string value, MemberInfo field)
 		{
-			return GetValue(fieldName, fieldType, new MiniYaml(value), field);
+			return GetValue(fieldName, fieldType, value, null, field);
 		}
 
 		public static object GetValue(string fieldName, Type fieldType, MiniYaml yaml, MemberInfo field)
 		{
-			var value = yaml.Value?.Trim();
+			return GetValue(fieldName, fieldType, yaml.Value, yaml, field);
+		}
+
+		static object GetValue(string fieldName, Type fieldType, string value, MiniYaml yaml, MemberInfo field)
+		{
+			value = value?.Trim();
 			if (fieldType.IsGenericType)
 			{
 				if (GenericTypeParsers.TryGetValue(fieldType.GetGenericTypeDefinition(), out var parseFuncGeneric))

OpenRA.Game/Graphics/Animation.cs

@@ -30,7 +30,7 @@ namespace OpenRA.Graphics
 		bool backwards;
 		bool tickAlways;
 		int timeUntilNextFrame;
-		Action tickFunc = () => { };
+		Action tickFunc;
 
 		public Animation(World world, string name)
 			: this(world, name, () => WAngle.Zero) { }
@@ -164,7 +164,7 @@ namespace OpenRA.Graphics
 				if (frame >= CurrentSequence.Length)
 				{
 					frame = CurrentSequence.Length - 1;
-					tickFunc = () => { };
+					tickFunc = null;
 					after?.Invoke();
 				}
 			};
@@ -212,13 +212,13 @@ namespace OpenRA.Graphics
 		public void Tick(int t)
 		{
 			if (tickAlways)
-				tickFunc();
+				tickFunc?.Invoke();
 			else
 			{
 				timeUntilNextFrame -= t;
 				while (timeUntilNextFrame <= 0)
 				{
-					tickFunc();
+					tickFunc?.Invoke();
 					timeUntilNextFrame += CurrentSequenceTickOrDefault();
 				}
 			}

OpenRA.Mods.Cnc/FileFormats/VxlReader.cs

@@ -15,10 +15,15 @@ using System.IO;
 namespace OpenRA.Mods.Cnc.FileFormats
 {
 	public enum NormalType { TiberianSun = 2, RedAlert2 = 4 }
-	public class VxlElement
+	public readonly struct VxlElement
 	{
-		public byte Color;
+		public readonly byte Color;
-		public byte Normal;
+		public readonly byte Normal;
+		public VxlElement(byte color, byte normal)
+		{
+			Color = color;
+			Normal = normal;
+		}
 	}
 
 	public class VxlLimb
@@ -83,20 +88,17 @@ namespace OpenRA.Mods.Cnc.FileFormats
 				var x = (byte)(i % l.Size[0]);
 				var y = (byte)(i / l.Size[0]);
 				byte z = 0;
-				l.VoxelMap[x, y] = new Dictionary<byte, VxlElement>();
+				var voxelMap = new Dictionary<byte, VxlElement>();
+				l.VoxelMap[x, y] = voxelMap;
 				do
 				{
 					z += s.ReadUInt8();
 					var count = s.ReadUInt8();
+					voxelMap.EnsureCapacity(voxelMap.Count + count);
 					for (var j = 0; j < count; j++)
 					{
-						var v = new VxlElement
+						var v = new VxlElement(s.ReadUInt8(), s.ReadUInt8());
-						{
+						voxelMap.Add(z, v);
-							Color = s.ReadUInt8(),
-							Normal = s.ReadUInt8()
-						};
-
-						l.VoxelMap[x, y].Add(z, v);
 						z++;
 					}
 

OpenRA.Mods.Cnc/Graphics/VoxelLoader.cs

@@ -57,7 +57,7 @@ namespace OpenRA.Mods.Cnc.Graphics
 			sheetBuilder = CreateSheetBuilder();
 		}
 
-		Vertex[] GenerateSlicePlane(int su, int sv, Func<int, int, VxlElement> first, Func<int, int, VxlElement> second, Func<int, int, float3> coord)
+		Vertex[] GenerateSlicePlane(int su, int sv, Func<int, int, VxlElement?> first, Func<int, int, VxlElement?> second, Func<int, int, float3> coord)
 		{
 			var colors = new byte[su * sv];
 			var normals = new byte[su * sv];
@@ -68,8 +68,8 @@ namespace OpenRA.Mods.Cnc.Graphics
 				for (var u = 0; u < su; u++)
 				{
 					var voxel = first(u, v) ?? second(u, v);
-					colors[c] = voxel == null ? (byte)0 : voxel.Color;
+					colors[c] = voxel == null ? (byte)0 : voxel.Value.Color;
-					normals[c] = voxel == null ? (byte)0 : voxel.Normal;
+					normals[c] = voxel == null ? (byte)0 : voxel.Value.Normal;
 					c++;
 				}
 			}
@@ -99,7 +99,7 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		IEnumerable<Vertex[]> GenerateSlicePlanes(VxlLimb l)
 		{
-			VxlElement Get(int x, int y, int z)
+			VxlElement? Get(int x, int y, int z)
 			{
 				if (x < 0 || y < 0 || z < 0)
 					return null;

OpenRA.Mods.Common/Traits/World/Locomotor.cs

@@ -84,8 +84,9 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected static object LoadSpeeds(MiniYaml y)
 		{
-			var ret = new Dictionary<string, TerrainInfo>();
+			var speeds = y.ToDictionary()["TerrainSpeeds"].Nodes;
-			foreach (var t in y.ToDictionary()["TerrainSpeeds"].Nodes)
+			var ret = new Dictionary<string, TerrainInfo>(speeds.Count);
+			foreach (var t in speeds)
 			{
 				var speed = FieldLoader.GetValue<int>("speed", t.Value.Value);
 				if (speed > 0)
@@ -98,6 +99,7 @@ namespace OpenRA.Mods.Common.Traits
 				}
 			}
 
+			ret.TrimExcess();
 			return ret;
 		}