Implement a new JIT for Arm devices (#6057)

* Implement a new JIT for Arm devices

* Auto-format

* Make a lot of Assembler members read-only

* More read-only

* Fix more warnings

* ObjectDisposedException.ThrowIf

* New JIT cache for platforms that enforce W^X, currently unused

* Remove unused using

* Fix assert

* Pass memory manager type around

* Safe memory manager mode support + other improvements

* Actual safe memory manager mode masking support

* PR feedback

src/Ryujinx.Cpu/LightningJit/State/NativeContext.cs

@@ -0,0 +1,173 @@
+using ARMeilleure.Memory;
+using ARMeilleure.State;
+using System;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Cpu.LightningJit.State
+{
+    class NativeContext : IDisposable
+    {
+        private unsafe struct NativeCtxStorage
+        {
+            public fixed ulong X[32];
+            public fixed ulong V[64];
+            public uint Flags;
+            public uint FpFlags;
+            public long TpidrEl0;
+            public long TpidrroEl0;
+            public int Counter;
+            public uint HostFpFlags;
+            public ulong DispatchAddress;
+            public int Running;
+        }
+
+        private static NativeCtxStorage _dummyStorage = new();
+
+        private readonly IJitMemoryBlock _block;
+
+        public IntPtr BasePtr => _block.Pointer;
+
+        public NativeContext(IJitMemoryAllocator allocator)
+        {
+            _block = allocator.Allocate((ulong)Unsafe.SizeOf<NativeCtxStorage>());
+        }
+
+        public ulong GetPc()
+        {
+            // TODO: More precise tracking of PC value.
+            return GetStorage().DispatchAddress;
+        }
+
+        public unsafe ulong GetX(int index)
+        {
+            if ((uint)index >= 32)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            return GetStorage().X[index];
+        }
+
+        public unsafe void SetX(int index, ulong value)
+        {
+            if ((uint)index >= 32)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            GetStorage().X[index] = value;
+        }
+
+        public unsafe V128 GetV(int index)
+        {
+            if ((uint)index >= 32)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            return new V128(GetStorage().V[index * 2 + 0], GetStorage().V[index * 2 + 1]);
+        }
+
+        public unsafe void SetV(int index, V128 value)
+        {
+            if ((uint)index >= 32)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            GetStorage().V[index * 2 + 0] = value.Extract<ulong>(0);
+            GetStorage().V[index * 2 + 1] = value.Extract<ulong>(1);
+        }
+
+        public unsafe uint GetPstate()
+        {
+            return GetStorage().Flags;
+        }
+
+        public unsafe void SetPstate(uint value)
+        {
+            GetStorage().Flags = value;
+        }
+
+        public unsafe uint GetFPState(uint mask = uint.MaxValue)
+        {
+            return GetStorage().FpFlags & mask;
+        }
+
+        public unsafe void SetFPState(uint value, uint mask = uint.MaxValue)
+        {
+            GetStorage().FpFlags = (value & mask) | (GetStorage().FpFlags & ~mask);
+        }
+
+        public long GetTpidrEl0() => GetStorage().TpidrEl0;
+        public void SetTpidrEl0(long value) => GetStorage().TpidrEl0 = value;
+
+        public long GetTpidrroEl0() => GetStorage().TpidrroEl0;
+        public void SetTpidrroEl0(long value) => GetStorage().TpidrroEl0 = value;
+
+        public int GetCounter() => GetStorage().Counter;
+        public void SetCounter(int value) => GetStorage().Counter = value;
+
+        public bool GetRunning() => GetStorage().Running != 0;
+        public void SetRunning(bool value) => GetStorage().Running = value ? 1 : 0;
+
+        public unsafe static int GetXOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.X[0]);
+        }
+
+        public unsafe static int GetVOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.V[0]);
+        }
+
+        public static int GetFlagsOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.Flags);
+        }
+
+        public static int GetFpFlagsOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.FpFlags);
+        }
+
+        public static int GetTpidrEl0Offset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.TpidrEl0);
+        }
+
+        public static int GetTpidrroEl0Offset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.TpidrroEl0);
+        }
+
+        public static int GetCounterOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.Counter);
+        }
+
+        public static int GetHostFpFlagsOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.HostFpFlags);
+        }
+
+        public static int GetDispatchAddressOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.DispatchAddress);
+        }
+
+        public static int GetRunningOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.Running);
+        }
+
+        private static int StorageOffset<T>(ref NativeCtxStorage storage, ref T target)
+        {
+            return (int)Unsafe.ByteOffset(ref Unsafe.As<NativeCtxStorage, T>(ref storage), ref target);
+        }
+
+        private unsafe ref NativeCtxStorage GetStorage() => ref Unsafe.AsRef<NativeCtxStorage>((void*)_block.Pointer);
+
+        public void Dispose() => _block.Dispose();
+    }
+}