Make structs readonly when applicable (#4002)

* Make all structs readonly when applicable. It should reduce amount of needless defensive copies

* Make structs with trivial boilerplate equality code record structs

* Remove unnecessary readonly modifiers from TextureCreateInfo

* Make BitMap structs readonly too

Ryujinx.Graphics.Shader/CodeGen/Glsl/Instructions/InstInfo.cs

@@ -1,6 +1,6 @@
 namespace Ryujinx.Graphics.Shader.CodeGen.Glsl.Instructions
 {
-    struct InstInfo
+    readonly struct InstInfo
     {
         public InstType Type { get; }
 

Ryujinx.Graphics.Shader/CodeGen/Glsl/OperandManager.cs

@@ -13,7 +13,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
     {
         private static readonly string[] StagePrefixes = new string[] { "cp", "vp", "tcp", "tep", "gp", "fp" };
 
-        private struct BuiltInAttribute
+        private readonly struct BuiltInAttribute
         {
             public string Name { get; }
 

Ryujinx.Graphics.Shader/CodeGen/Spirv/OperationResult.cs

@@ -3,7 +3,7 @@ using Spv.Generator;
 
 namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 {
-    struct OperationResult
+    readonly struct OperationResult
     {
         public static OperationResult Invalid => new OperationResult(AggregateType.Invalid, null);
 

Ryujinx.Graphics.Shader/CodeGen/Spirv/SpirvDelegates.cs

@@ -8,7 +8,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
     /// <summary>
     /// Delegate cache for SPIR-V instruction generators. Avoids delegate allocation when passing generators as arguments.
     /// </summary>
-    internal struct SpirvDelegates
+    internal readonly struct SpirvDelegates
     {
         // Unary
         public readonly FuncUnaryInstruction GlslFAbs;

Ryujinx.Graphics.Shader/CodeGen/Spirv/TextureMeta.cs

@@ -1,33 +1,4 @@
-using System;
-
-namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
+namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 {
-    struct TextureMeta : IEquatable<TextureMeta>
-    {
-        public int CbufSlot { get; }
-        public int Handle { get; }
-        public TextureFormat Format { get; }
-
-        public TextureMeta(int cbufSlot, int handle, TextureFormat format)
-        {
-            CbufSlot = cbufSlot;
-            Handle = handle;
-            Format = format;
-        }
-
-        public override bool Equals(object obj)
-        {
-            return obj is TextureMeta other && Equals(other);
-        }
-
-        public bool Equals(TextureMeta other)
-        {
-            return CbufSlot == other.CbufSlot && Handle == other.Handle && Format == other.Format;
-        }
-
-        public override int GetHashCode()
-        {
-            return HashCode.Combine(CbufSlot, Handle, Format);
-        }
-    }
+    readonly record struct TextureMeta(int CbufSlot, int Handle, TextureFormat Format);
 }

Ryujinx.Graphics.Shader/Decoders/Block.cs

@@ -17,7 +17,7 @@ namespace Ryujinx.Graphics.Shader.Decoders
         }
     }
 
-    struct SyncTarget
+    readonly struct SyncTarget
     {
         public PushOpInfo PushOpInfo { get; }
         public int PushOpId { get; }

Ryujinx.Graphics.Shader/Decoders/DecodedProgram.cs

@@ -4,7 +4,7 @@ using System.Collections.Generic;
 
 namespace Ryujinx.Graphics.Shader.Decoders
 {
-    struct DecodedProgram : IEnumerable<DecodedFunction>
+    readonly struct DecodedProgram : IEnumerable<DecodedFunction>
     {
         public DecodedFunction MainFunction { get; }
         private readonly IReadOnlyDictionary<ulong, DecodedFunction> _functions;

Ryujinx.Graphics.Shader/Decoders/Decoder.cs

@@ -473,7 +473,7 @@ namespace Ryujinx.Graphics.Shader.Decoders
             op = Unsafe.As<ulong, T>(ref rawOp);
         }
 
-        private struct BlockLocation
+        private readonly struct BlockLocation
         {
             public Block Block { get; }
             public int Index { get; }

Ryujinx.Graphics.Shader/Decoders/InstTable.cs

@@ -6,7 +6,7 @@ namespace Ryujinx.Graphics.Shader.Decoders
     {
         private const int EncodingBits = 14;
 
-        private struct TableEntry
+        private readonly struct TableEntry
         {
             public InstName Name { get; }
             public InstEmitter Emitter { get; }

Ryujinx.Graphics.Shader/Decoders/Register.cs

@@ -2,7 +2,7 @@ using System;
 
 namespace Ryujinx.Graphics.Shader.Decoders
 {
-    struct Register : IEquatable<Register>
+    readonly struct Register : IEquatable<Register>
     {
         public int Index { get; }
 

Ryujinx.Graphics.Shader/StructuredIr/InstructionInfo.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Shader.StructuredIr
 {
     static class InstructionInfo
     {
-        private struct InstInfo
+        private readonly struct InstInfo
         {
             public VariableType DestType { get; }
 

Ryujinx.Graphics.Shader/StructuredIr/StructuredProgramInfo.cs

@@ -2,7 +2,7 @@ using System.Collections.Generic;
 
 namespace Ryujinx.Graphics.Shader.StructuredIr
 {
-    struct TransformFeedbackOutput
+    readonly struct TransformFeedbackOutput
     {
         public readonly bool Valid;
         public readonly int Buffer;

Ryujinx.Graphics.Shader/Translation/AttributeInfo.cs

@@ -2,7 +2,7 @@
 
 namespace Ryujinx.Graphics.Shader.Translation
 {
-    struct AttributeInfo
+    readonly struct AttributeInfo
     {
         private static readonly Dictionary<int, AttributeInfo> _builtInAttributes = new Dictionary<int, AttributeInfo>()
         {

Ryujinx.Graphics.Shader/Translation/EmitterContext.cs

@@ -21,7 +21,7 @@ namespace Ryujinx.Graphics.Shader.Translation
 
         public int OperationsCount => _operations.Count;
 
-        private struct BrxTarget
+        private readonly struct BrxTarget
         {
             public readonly Operand Selector;
             public readonly int ExpectedValue;

Ryujinx.Graphics.Shader/Translation/FunctionMatch.cs

@@ -87,7 +87,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             }
         }
 
-        private struct TreeNodeUse
+        private readonly struct TreeNodeUse
         {
             public TreeNode Node { get; }
             public int Index { get; }
@@ -345,7 +345,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             bool Matches(in InstOp opInfo);
         }
 
-        private struct PatternTreeNodeUse
+        private readonly struct PatternTreeNodeUse
         {
             public IPatternTreeNode Node { get; }
             public int Index { get; }

Ryujinx.Graphics.Shader/Translation/RegisterUsage.cs

@@ -114,7 +114,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             }
         }
 
-        public struct FunctionRegisterUsage
+        public readonly struct FunctionRegisterUsage
         {
             public Register[] InArguments { get; }
             public Register[] OutArguments { get; }

Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs

@@ -69,36 +69,7 @@ namespace Ryujinx.Graphics.Shader.Translation
         private int _usedStorageBuffers;
         private int _usedStorageBuffersWrite;
 
-        private struct TextureInfo : IEquatable<TextureInfo>
-        {
-            public int CbufSlot { get; }
-            public int Handle { get; }
-            public bool Indexed { get; }
-            public TextureFormat Format { get; }
-
-            public TextureInfo(int cbufSlot, int handle, bool indexed, TextureFormat format)
-            {
-                CbufSlot = cbufSlot;
-                Handle = handle;
-                Indexed = indexed;
-                Format = format;
-            }
-
-            public override bool Equals(object obj)
-            {
-                return obj is TextureInfo other && Equals(other);
-            }
-
-            public bool Equals(TextureInfo other)
-            {
-                return CbufSlot == other.CbufSlot && Handle == other.Handle && Indexed == other.Indexed && Format == other.Format;
-            }
-
-            public override int GetHashCode()
-            {
-                return HashCode.Combine(CbufSlot, Handle, Indexed, Format);
-            }
-        }
+        private readonly record struct TextureInfo(int CbufSlot, int Handle, bool Indexed, TextureFormat Format);
 
         private struct TextureMeta
         {

Ryujinx.Graphics.Shader/Translation/ShaderHeader.cs

@@ -12,7 +12,7 @@ namespace Ryujinx.Graphics.Shader.Translation
         ScreenLinear = 3
     }
 
-    struct ImapPixelType
+    readonly struct ImapPixelType
     {
         public PixelImap X { get; }
         public PixelImap Y { get; }

Ryujinx.Graphics.Shader/Translation/Ssa.cs

@@ -108,7 +108,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             }
         }
 
-        private struct Definition
+        private readonly struct Definition
         {
             public BasicBlock Block { get; }
             public Operand    Local { get; }

Ryujinx.Graphics.Shader/Translation/TranslationOptions.cs

@@ -1,6 +1,6 @@
 namespace Ryujinx.Graphics.Shader.Translation
 {
-    public struct TranslationOptions
+    public readonly struct TranslationOptions
     {
         public TargetLanguage TargetLanguage { get; }
         public TargetApi TargetApi { get; }

Ryujinx.Graphics.Shader/Translation/Translator.cs

@@ -14,7 +14,7 @@ namespace Ryujinx.Graphics.Shader.Translation
     {
         private const int HeaderSize = 0x50;
 
-        internal struct FunctionCode
+        internal readonly struct FunctionCode
         {
             public Operation[] Code { get; }