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.Gpu/Engine/MME/IMacroEE.cs

@@ -7,7 +7,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.MME
     /// <summary>
     /// FIFO word.
     /// </summary>
-    struct FifoWord
+    readonly struct FifoWord
     {
         /// <summary>
         /// GPU virtual address where the word is located in memory.

Ryujinx.Graphics.Gpu/Engine/MME/MacroHLETable.cs

@@ -13,7 +13,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.MME
         /// <summary>
         /// Macroo High-level implementation table entry.
         /// </summary>
-        struct TableEntry
+        readonly struct TableEntry
         {
             /// <summary>
             /// Name of the Macro function.

Ryujinx.Graphics.Gpu/Engine/Threed/StateUpdateTracker.cs

@@ -11,7 +11,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
     /// <summary>
     /// State update callback entry, with the callback function and associated field names.
     /// </summary>
-    struct StateUpdateCallbackEntry
+    readonly struct StateUpdateCallbackEntry
     {
         /// <summary>
         /// Callback function, to be called if the register was written as the state needs to be updated.

Ryujinx.Graphics.Gpu/Image/FormatInfo.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// Represents texture format information.
     /// </summary>
-    struct FormatInfo
+    readonly struct FormatInfo
     {
         /// <summary>
         /// A default, generic RGBA8 texture format.

Ryujinx.Graphics.Gpu/Image/TextureBindingInfo.cs

@@ -7,7 +7,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// Texture binding information.
     /// This is used for textures that needs to be accessed from shaders.
     /// </summary>
-    struct TextureBindingInfo
+    readonly struct TextureBindingInfo
     {
         /// <summary>
         /// Shader sampler target type.

Ryujinx.Graphics.Gpu/Image/TextureCache.cs

@@ -16,7 +16,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// </summary>
     class TextureCache : IDisposable
     {
-        private struct OverlapInfo
+        private readonly struct OverlapInfo
         {
             public TextureViewCompatibility Compatibility { get; }
             public int FirstLayer { get; }

Ryujinx.Graphics.Gpu/Image/TextureGroup.cs

@@ -14,7 +14,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// An overlapping texture group with a given view compatibility.
     /// </summary>
-    struct TextureIncompatibleOverlap
+    readonly struct TextureIncompatibleOverlap
     {
         public readonly TextureGroup Group;
         public readonly TextureViewCompatibility Compatibility;

Ryujinx.Graphics.Gpu/Image/TextureInfo.cs

@@ -6,7 +6,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// Texture information.
     /// </summary>
-    struct TextureInfo
+    readonly struct TextureInfo
     {
         /// <summary>
         /// Address of the texture in GPU mapped memory.

Ryujinx.Graphics.Gpu/Memory/BufferBounds.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
     /// <summary>
     /// Memory range used for buffers.
     /// </summary>
-    struct BufferBounds
+    readonly struct BufferBounds
     {
         /// <summary>
         /// Region virtual address.

Ryujinx.Graphics.Gpu/Memory/BufferTextureBinding.cs

@@ -7,7 +7,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
     /// <summary>
     /// A buffer binding to apply to a buffer texture.
     /// </summary>
-    struct BufferTextureBinding
+    readonly struct BufferTextureBinding
     {
         /// <summary>
         /// Shader stage accessing the texture.

Ryujinx.Graphics.Gpu/Memory/CounterCache.cs

@@ -8,7 +8,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
     /// </summary>
     class CounterCache
     {
-        private struct CounterEntry
+        private readonly struct CounterEntry
         {
             public ulong Address { get; }
             public ICounterEvent Event { get; }

Ryujinx.Graphics.Gpu/Shader/DiskCache/BackgroundDiskCacheWriter.cs

@@ -24,7 +24,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         /// <summary>
         /// Represents an operation to perform on the <see cref="_fileWriterWorkerQueue"/>.
         /// </summary>
-        private struct CacheFileOperationTask
+        private readonly struct CacheFileOperationTask
         {
             /// <summary>
             /// The type of operation to perform.
@@ -46,7 +46,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         /// <summary>
         /// Background shader cache write information.
         /// </summary>
-        private struct AddShaderData
+        private readonly struct AddShaderData
         {
             /// <summary>
             /// Cached shader program.

Ryujinx.Graphics.Gpu/Shader/DiskCache/GuestCodeAndCbData.cs

@@ -3,7 +3,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
     /// <summary>
     /// Guest shader code and constant buffer data accessed by the shader.
     /// </summary>
-    struct GuestCodeAndCbData
+    readonly struct GuestCodeAndCbData
     {
         /// <summary>
         /// Maxwell binary shader code.

Ryujinx.Graphics.Gpu/Shader/DiskCache/ParallelDiskCacheLoader.cs

@@ -37,7 +37,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         /// <summary>
         /// Program validation entry.
         /// </summary>
-        private struct ProgramEntry
+        private readonly struct ProgramEntry
         {
             /// <summary>
             /// Cached shader program.
@@ -90,7 +90,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         /// <summary>
         /// Translated shader compilation entry.
         /// </summary>
-        private struct ProgramCompilation
+        private readonly struct ProgramCompilation
         {
             /// <summary>
             /// Translated shader stages.
@@ -143,7 +143,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         /// <summary>
         /// Program translation entry.
         /// </summary>
-        private struct AsyncProgramTranslation
+        private readonly struct AsyncProgramTranslation
         {
             /// <summary>
             /// Guest code for each active stage.

Ryujinx.Graphics.Gpu/Shader/GpuChannelComputeState.cs

@@ -3,7 +3,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
     /// <summary>
     /// State used by the <see cref="GpuAccessor"/>.
     /// </summary>
-    struct GpuChannelComputeState
+    readonly struct GpuChannelComputeState
     {
         // New fields should be added to the end of the struct to keep disk shader cache compatibility.
 

Ryujinx.Graphics.Gpu/Shader/GpuChannelPoolState.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
     /// <summary>
     /// State used by the <see cref="GpuAccessor"/>.
     /// </summary>
-    struct GpuChannelPoolState : IEquatable<GpuChannelPoolState>
+    readonly struct GpuChannelPoolState : IEquatable<GpuChannelPoolState>
     {
         /// <summary>
         /// GPU virtual address of the texture pool.

Ryujinx.Graphics.Gpu/Shader/HashTable/PartitionedHashTable.cs

@@ -13,7 +13,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.HashTable
         /// <summary>
         /// Entry for a given data size.
         /// </summary>
-        private struct SizeEntry
+        private readonly struct SizeEntry
         {
             /// <summary>
             /// Size for the data that will be stored on the hash table on this entry.

Ryujinx.Graphics.Gpu/Shader/ShaderCache.cs

@@ -26,7 +26,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
         /// </summary>
         public const TranslationFlags DefaultFlags = TranslationFlags.DebugMode;
 
-        private struct TranslatedShader
+        private readonly struct TranslatedShader
         {
             public readonly CachedShaderStage Shader;
             public readonly ShaderProgram Program;
@@ -38,7 +38,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
             }
         }
 
-        private struct TranslatedShaderVertexPair
+        private readonly struct TranslatedShaderVertexPair
         {
             public readonly CachedShaderStage VertexA;
             public readonly CachedShaderStage VertexB;
@@ -59,7 +59,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
         private readonly Dictionary<ulong, CachedShaderProgram> _cpPrograms;
         private readonly Dictionary<ShaderAddresses, CachedShaderProgram> _gpPrograms;
 
-        private struct ProgramToSave
+        private readonly struct ProgramToSave
         {
             public readonly CachedShaderProgram CachedProgram;
             public readonly IProgram HostProgram;

Ryujinx.Graphics.Gpu/Shader/ShaderCodeAccessor.cs

@@ -7,7 +7,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
     /// <summary>
     /// Shader code accessor.
     /// </summary>
-    struct ShaderCodeAccessor : IDataAccessor
+    readonly struct ShaderCodeAccessor : IDataAccessor
     {
         private readonly MemoryManager _memoryManager;
         private readonly ulong _baseAddress;

Ryujinx.Graphics.Gpu/Shader/ShaderDumpPaths.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
     /// <summary>
     /// Paths where shader code was dumped on disk.
     /// </summary>
-    struct ShaderDumpPaths
+    readonly struct ShaderDumpPaths
     {
         /// <summary>
         /// Path where the full shader code with header was dumped, or null if not dumped.

Ryujinx.Graphics.Gpu/Shader/ShaderSpecializationState.cs

@@ -121,7 +121,7 @@ namespace Ryujinx.Graphics.Gpu.Shader
         /// <summary>
         /// Texture binding information, used to identify each texture accessed by the shader.
         /// </summary>
-        private struct TextureKey : IEquatable<TextureKey>
+        private readonly record struct TextureKey
         {
             // New fields should be added to the end of the struct to keep disk shader cache compatibility.
 
@@ -152,21 +152,6 @@ namespace Ryujinx.Graphics.Gpu.Shader
                 Handle = handle;
                 CbufSlot = cbufSlot;
             }
-
-            public override bool Equals(object obj)
-            {
-                return obj is TextureKey textureKey && Equals(textureKey);
-            }
-
-            public bool Equals(TextureKey other)
-            {
-                return StageIndex == other.StageIndex && Handle == other.Handle && CbufSlot == other.CbufSlot;
-            }
-
-            public override int GetHashCode()
-            {
-                return HashCode.Combine(StageIndex, Handle, CbufSlot);
-            }
         }
 
         private readonly Dictionary<TextureKey, Box<TextureSpecializationState>> _textureSpecialization;

Ryujinx.Graphics.Gpu/Window.cs

@@ -20,7 +20,7 @@ namespace Ryujinx.Graphics.Gpu
         /// <summary>
         /// Texture presented on the window.
         /// </summary>
-        private struct PresentationTexture
+        private readonly struct PresentationTexture
         {
             /// <summary>
             /// Texture cache where the texture might be located.