some initial metal commits cherry-picked

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

@@ -0,0 +1,17 @@
+using Ryujinx.Graphics.Shader.StructuredIr;
+using Ryujinx.Graphics.Shader.Translation;
+
+namespace Ryujinx.Graphics.Shader.CodeGen.Msl
+{
+    static class MslGenerator
+    {
+        public static string Generate(StructuredProgramInfo info, ShaderConfig config)
+        {
+            CodeGenContext context = new CodeGenContext(info, config);
+
+            Declarations.Declare(context, info);
+
+            return context.GetCode();
+        }
+    }
+}