Add GDB Stub

src/ARMeilleure/State/ExecutionContext.cs

@@ -1,5 +1,6 @@
 using ARMeilleure.Memory;
 using System;
+using System.Threading;
 
 namespace ARMeilleure.State
 {
@@ -11,7 +12,7 @@ namespace ARMeilleure.State
 
         internal IntPtr NativeContextPtr => _nativeContext.BasePtr;
 
-        private bool _interrupted;
+        internal bool Interrupted { get; private set; }
 
         private readonly ICounter _counter;
 
@@ -68,6 +69,8 @@ namespace ARMeilleure.State
 
         public bool IsAarch32 { get; set; }
 
+        public ulong ThreadUid { get; set; }
+
         internal ExecutionMode ExecutionMode
         {
             get
@@ -93,14 +96,19 @@ namespace ARMeilleure.State
 
         private readonly ExceptionCallbackNoArgs _interruptCallback;
         private readonly ExceptionCallback _breakCallback;
+        private readonly ExceptionCallbackNoArgs _stepCallback;
         private readonly ExceptionCallback _supervisorCallback;
         private readonly ExceptionCallback _undefinedCallback;
 
+        internal int ShouldStep;
+        public ulong DebugPc { get; set; }
+
         public ExecutionContext(
             IJitMemoryAllocator allocator,
             ICounter counter,
             ExceptionCallbackNoArgs interruptCallback = null,
             ExceptionCallback breakCallback = null,
+            ExceptionCallbackNoArgs stepCallback = null,
             ExceptionCallback supervisorCallback = null,
             ExceptionCallback undefinedCallback = null)
         {
@@ -108,6 +116,7 @@ namespace ARMeilleure.State
             _counter = counter;
             _interruptCallback = interruptCallback;
             _breakCallback = breakCallback;
+            _stepCallback = stepCallback;
             _supervisorCallback = supervisorCallback;
             _undefinedCallback = undefinedCallback;
 
@@ -130,9 +139,9 @@ namespace ARMeilleure.State
 
         internal void CheckInterrupt()
         {
-            if (_interrupted)
+            if (Interrupted)
             {
-                _interrupted = false;
+                Interrupted = false;
 
                 _interruptCallback?.Invoke(this);
             }
@@ -142,16 +151,37 @@ namespace ARMeilleure.State
 
         public void RequestInterrupt()
         {
-            _interrupted = true;
+            Interrupted = true;
+        }
+
+        public void StepHandler()
+        {
+            _stepCallback?.Invoke(this);
+        }
+
+        public void RequestDebugStep()
+        {
+            Interlocked.Exchange(ref ShouldStep, 1);
+            RequestInterrupt();
         }
 
         internal void OnBreak(ulong address, int imm)
         {
+            if (Optimizations.EnableDebugging)
+            {
+                DebugPc = Pc;
+            }
+
             _breakCallback?.Invoke(this, address, imm);
         }
 
         internal void OnSupervisorCall(ulong address, int imm)
         {
+            if (Optimizations.EnableDebugging)
+            {
+                DebugPc = Pc;
+            }
+
             _supervisorCallback?.Invoke(this, address, imm);
         }
 

src/ARMeilleure/State/NativeContext.cs

@@ -22,6 +22,12 @@ namespace ARMeilleure.State
             public ulong ExclusiveValueHigh;
             public int Running;
             public long Tpidr2El0;
+            
+            /// <summary>
+            /// Precise PC value used for debugging.
+            /// This will only be set when Optimizations.EnableDebugging is true.
+            /// </summary>
+            public ulong DebugPrecisePc;
         }
 
         private static NativeCtxStorage _dummyStorage = new();
@@ -39,6 +45,11 @@ namespace ARMeilleure.State
 
         public ulong GetPc()
         {
+            if (Optimizations.EnableDebugging)
+            {
+                return GetStorage().DebugPrecisePc;
+            }
+
             // TODO: More precise tracking of PC value.
             return GetStorage().DispatchAddress;
         }
@@ -266,6 +277,11 @@ namespace ARMeilleure.State
             return StorageOffset(ref _dummyStorage, ref _dummyStorage.Running);
         }
 
+        public static int GetDebugPrecisePcOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.DebugPrecisePc);
+        }
+
         private static int StorageOffset<T>(ref NativeCtxStorage storage, ref T target)
         {
             return (int)Unsafe.ByteOffset(ref Unsafe.As<NativeCtxStorage, T>(ref storage), ref target);