EXPERIMENTAL: Metal backend (#441)

This is not a continuation of the Metal backend; this is simply bringing
the branch up to date and merging it as-is behind an experiment.

---------

Co-authored-by: Isaac Marovitz <isaacryu@icloud.com>
Co-authored-by: Samuliak <samuliak77@gmail.com>
Co-authored-by: SamoZ256 <96914946+SamoZ256@users.noreply.github.com>
Co-authored-by: Isaac Marovitz <42140194+IsaacMarovitz@users.noreply.github.com>
Co-authored-by: riperiperi <rhy3756547@hotmail.com>
Co-authored-by: Gabriel A <gab.dark.100@gmail.com>

src/Ryujinx.Graphics.Shader/CodeGen/Msl/CodeGenContext.cs

@@ -0,0 +1,108 @@
+using Ryujinx.Graphics.Shader.StructuredIr;
+using Ryujinx.Graphics.Shader.Translation;
+using System.Text;
+
+namespace Ryujinx.Graphics.Shader.CodeGen.Msl
+{
+    class CodeGenContext
+    {
+        public const string Tab = "    ";
+
+        // The number of additional arguments that every function (except for the main one) must have (for instance support_buffer)
+        public const int AdditionalArgCount = 2;
+
+        public StructuredFunction CurrentFunction { get; set; }
+
+        public StructuredProgramInfo Info { get; }
+
+        public AttributeUsage AttributeUsage { get; }
+        public ShaderDefinitions Definitions { get; }
+        public ShaderProperties Properties { get; }
+        public HostCapabilities HostCapabilities { get; }
+        public ILogger Logger { get; }
+        public TargetApi TargetApi { get; }
+
+        public OperandManager OperandManager { get; }
+
+        private readonly StringBuilder _sb;
+
+        private int _level;
+
+        private string _indentation;
+
+        public CodeGenContext(StructuredProgramInfo info, CodeGenParameters parameters)
+        {
+            Info = info;
+            AttributeUsage = parameters.AttributeUsage;
+            Definitions = parameters.Definitions;
+            Properties = parameters.Properties;
+            HostCapabilities = parameters.HostCapabilities;
+            Logger = parameters.Logger;
+            TargetApi = parameters.TargetApi;
+
+            OperandManager = new OperandManager();
+
+            _sb = new StringBuilder();
+        }
+
+        public void AppendLine()
+        {
+            _sb.AppendLine();
+        }
+
+        public void AppendLine(string str)
+        {
+            _sb.AppendLine(_indentation + str);
+        }
+
+        public string GetCode()
+        {
+            return _sb.ToString();
+        }
+
+        public void EnterScope(string prefix = "")
+        {
+            AppendLine(prefix + "{");
+
+            _level++;
+
+            UpdateIndentation();
+        }
+
+        public void LeaveScope(string suffix = "")
+        {
+            if (_level == 0)
+            {
+                return;
+            }
+
+            _level--;
+
+            UpdateIndentation();
+
+            AppendLine("}" + suffix);
+        }
+
+        public StructuredFunction GetFunction(int id)
+        {
+            return Info.Functions[id];
+        }
+
+        private void UpdateIndentation()
+        {
+            _indentation = GetIndentation(_level);
+        }
+
+        private static string GetIndentation(int level)
+        {
+            string indentation = string.Empty;
+
+            for (int index = 0; index < level; index++)
+            {
+                indentation += Tab;
+            }
+
+            return indentation;
+        }
+    }
+}