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

7 files changed, 21 insertions, 19 deletions

diff --git a/src/ARMeilleure/Common/AddressTable.cs b/src/ARMeilleure/Common/AddressTable.cs
index c9b0062b..fcab3a20 100644
--- a/src/ARMeilleure/Common/AddressTable.cs
+++ b/src/ARMeilleure/Common/AddressTable.cs
@@ -9,7 +9,7 @@ namespace ARMeilleure.Common
     /// Represents a table of guest address to a value.
     /// </summary>
     /// <typeparam name="TEntry">Type of the value</typeparam>
-    unsafe class AddressTable<TEntry> : IDisposable where TEntry : unmanaged
+    public unsafe class AddressTable<TEntry> : IDisposable where TEntry : unmanaged
     {
         /// <summary>
         /// Represents a level in an <see cref="AddressTable{TEntry}"/>.
diff --git a/src/ARMeilleure/Memory/IJitMemoryBlock.cs b/src/ARMeilleure/Memory/IJitMemoryBlock.cs
index cd49f314..c103fe8d 100644
--- a/src/ARMeilleure/Memory/IJitMemoryBlock.cs
+++ b/src/ARMeilleure/Memory/IJitMemoryBlock.cs
@@ -8,6 +8,7 @@ namespace ARMeilleure.Memory
 
         void Commit(ulong offset, ulong size);
 
+        void MapAsRw(ulong offset, ulong size);
         void MapAsRx(ulong offset, ulong size);
         void MapAsRwx(ulong offset, ulong size);
     }
diff --git a/src/ARMeilleure/Memory/ReservedRegion.cs b/src/ARMeilleure/Memory/ReservedRegion.cs
index d0ffa8f1..3870d4c8 100644
--- a/src/ARMeilleure/Memory/ReservedRegion.cs
+++ b/src/ARMeilleure/Memory/ReservedRegion.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace ARMeilleure.Memory
 {
-    class ReservedRegion
+    public class ReservedRegion
     {
         public const int DefaultGranularity = 65536; // Mapping granularity in Windows.
 
diff --git a/src/ARMeilleure/Native/JitSupportDarwin.cs b/src/ARMeilleure/Native/JitSupportDarwin.cs
index ed347b9c..33946039 100644
--- a/src/ARMeilleure/Native/JitSupportDarwin.cs
+++ b/src/ARMeilleure/Native/JitSupportDarwin.cs
@@ -5,7 +5,7 @@ using System.Runtime.Versioning;
 namespace ARMeilleure.Native
 {
     [SupportedOSPlatform("macos")]
-    internal static partial class JitSupportDarwin
+    static partial class JitSupportDarwin
     {
         [LibraryImport("libarmeilleure-jitsupport", EntryPoint = "armeilleure_jit_memcpy")]
         public static partial void Copy(IntPtr dst, IntPtr src, ulong n);
diff --git a/src/ARMeilleure/Translation/IntervalTree.cs b/src/ARMeilleure/Translation/IntervalTree.cs
index da29d6a6..a5f9b5d5 100644
--- a/src/ARMeilleure/Translation/IntervalTree.cs
+++ b/src/ARMeilleure/Translation/IntervalTree.cs
@@ -8,7 +8,7 @@ namespace ARMeilleure.Translation
     /// </summary>
     /// <typeparam name="TK">Key</typeparam>
     /// <typeparam name="TV">Value</typeparam>
-    class IntervalTree<TK, TV> where TK : IComparable<TK>
+    public class IntervalTree<TK, TV> where TK : IComparable<TK>
     {
         private const int ArrayGrowthSize = 32;
 
diff --git a/src/ARMeilleure/Translation/Translator.cs b/src/ARMeilleure/Translation/Translator.cs
index 48c1a575..014b1203 100644
--- a/src/ARMeilleure/Translation/Translator.cs
+++ b/src/ARMeilleure/Translation/Translator.cs
@@ -73,7 +73,7 @@ namespace ARMeilleure.Translation
             CountTable = new EntryTable<uint>();
             Functions = new TranslatorCache<TranslatedFunction>();
             FunctionTable = new AddressTable<ulong>(for64Bits ? _levels64Bit : _levels32Bit);
-            Stubs = new TranslatorStubs(this);
+            Stubs = new TranslatorStubs(FunctionTable);
 
             FunctionTable.Fill = (ulong)Stubs.SlowDispatchStub;
         }
diff --git a/src/ARMeilleure/Translation/TranslatorStubs.cs b/src/ARMeilleure/Translation/TranslatorStubs.cs
index bbe48c16..d80823a8 100644
--- a/src/ARMeilleure/Translation/TranslatorStubs.cs
+++ b/src/ARMeilleure/Translation/TranslatorStubs.cs
@@ -1,3 +1,4 @@
+using ARMeilleure.Common;
 using ARMeilleure.Instructions;
 using ARMeilleure.IntermediateRepresentation;
 using ARMeilleure.State;
@@ -14,11 +15,11 @@ namespace ARMeilleure.Translation
     /// </summary>
     class TranslatorStubs : IDisposable
     {
-        private static readonly Lazy<IntPtr> _slowDispatchStub = new(GenerateSlowDispatchStub, isThreadSafe: true);
+        private readonly Lazy<IntPtr> _slowDispatchStub;
 
         private bool _disposed;
 
-        private readonly Translator _translator;
+        private readonly AddressTable<ulong> _functionTable;
         private readonly Lazy<IntPtr> _dispatchStub;
         private readonly Lazy<DispatcherFunction> _dispatchLoop;
         private readonly Lazy<WrapperFunction> _contextWrapper;
@@ -83,13 +84,14 @@ namespace ARMeilleure.Translation
         /// Initializes a new instance of the <see cref="TranslatorStubs"/> class with the specified
         /// <see cref="Translator"/> instance.
         /// </summary>
-        /// <param name="translator"><see cref="Translator"/> instance to use</param>
+        /// <param name="functionTable">Function table used to store pointers to the functions that the guest code will call</param>
         /// <exception cref="ArgumentNullException"><paramref name="translator"/> is null</exception>
-        public TranslatorStubs(Translator translator)
+        public TranslatorStubs(AddressTable<ulong> functionTable)
         {
-            ArgumentNullException.ThrowIfNull(translator);
+            ArgumentNullException.ThrowIfNull(functionTable);
 
-            _translator = translator;
+            _functionTable = functionTable;
+            _slowDispatchStub = new(GenerateSlowDispatchStub, isThreadSafe: true);
             _dispatchStub = new(GenerateDispatchStub, isThreadSafe: true);
             _dispatchLoop = new(GenerateDispatchLoop, isThreadSafe: true);
             _contextWrapper = new(GenerateContextWrapper, isThreadSafe: true);
@@ -151,15 +153,15 @@ namespace ARMeilleure.Translation
                 context.Add(nativeContext, Const((ulong)NativeContext.GetDispatchAddressOffset())));
 
             // Check if guest address is within range of the AddressTable.
-            Operand masked = context.BitwiseAnd(guestAddress, Const(~_translator.FunctionTable.Mask));
+            Operand masked = context.BitwiseAnd(guestAddress, Const(~_functionTable.Mask));
             context.BranchIfTrue(lblFallback, masked);
 
             Operand index = default;
-            Operand page = Const((long)_translator.FunctionTable.Base);
+            Operand page = Const((long)_functionTable.Base);
 
-            for (int i = 0; i < _translator.FunctionTable.Levels.Length; i++)
+            for (int i = 0; i < _functionTable.Levels.Length; i++)
             {
-                ref var level = ref _translator.FunctionTable.Levels[i];
+                ref var level = ref _functionTable.Levels[i];
 
                 // level.Mask is not used directly because it is more often bigger than 32-bits, so it will not
                 // be encoded as an immediate on x86's bitwise and operation.
@@ -167,7 +169,7 @@ namespace ARMeilleure.Translation
 
                 index = context.BitwiseAnd(context.ShiftRightUI(guestAddress, Const(level.Index)), mask);
 
-                if (i < _translator.FunctionTable.Levels.Length - 1)
+                if (i < _functionTable.Levels.Length - 1)
                 {
                     page = context.Load(OperandType.I64, context.Add(page, context.ShiftLeft(index, Const(3))));
                     context.BranchIfFalse(lblFallback, page);
@@ -196,7 +198,7 @@ namespace ARMeilleure.Translation
         /// Generates a <see cref="SlowDispatchStub"/>.
         /// </summary>
         /// <returns>Generated <see cref="SlowDispatchStub"/></returns>
-        private static IntPtr GenerateSlowDispatchStub()
+        private IntPtr GenerateSlowDispatchStub()
         {
             var context = new EmitterContext();
 
@@ -205,8 +207,7 @@ namespace ARMeilleure.Translation
             Operand guestAddress = context.Load(OperandType.I64,
                 context.Add(nativeContext, Const((ulong)NativeContext.GetDispatchAddressOffset())));
 
-            MethodInfo getFuncAddress = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFunctionAddress));
-            Operand hostAddress = context.Call(getFuncAddress, guestAddress);
+            Operand hostAddress = context.Call(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFunctionAddress)), guestAddress);
             context.Tailcall(hostAddress, nativeContext);
 
             var cfg = context.GetControlFlowGraph();