From 838296ccb63bb76b1d2d672f0794bab8e5678cd7 Mon Sep 17 00:00:00 2001
From: Coxxs <58-coxxs@users.noreply.git.ryujinx.app>
Date: Mon, 23 Jun 2025 07:00:48 +0800
Subject: [PATCH] gdb: Support precise tracking of PC value when GDB Stub is
 enabled

---
 src/ARMeilleure/State/ExecutionContext.cs | 10 ++++++++++
 src/ARMeilleure/State/NativeContext.cs    | 15 +++++++++++++++
 src/ARMeilleure/Translation/Translator.cs | 18 ++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/src/ARMeilleure/State/ExecutionContext.cs b/src/ARMeilleure/State/ExecutionContext.cs
index cdf6f56c5..fa1a4a032 100644
--- a/src/ARMeilleure/State/ExecutionContext.cs
+++ b/src/ARMeilleure/State/ExecutionContext.cs
@@ -164,11 +164,21 @@ namespace ARMeilleure.State
 
         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);
         }
 
diff --git a/src/ARMeilleure/State/NativeContext.cs b/src/ARMeilleure/State/NativeContext.cs
index c90e522a9..25b5e51c3 100644
--- a/src/ARMeilleure/State/NativeContext.cs
+++ b/src/ARMeilleure/State/NativeContext.cs
@@ -22,6 +22,11 @@ namespace ARMeilleure.State
             public ulong ExclusiveValueHigh;
             public int Running;
             public long Tpidr2El0;
+            
+            /// <summary>
+            /// This is only set when Optimizations.EnableDebugging is true.
+            /// </summary>
+            public ulong CurrentPc;
         }
 
         private static NativeCtxStorage _dummyStorage = new();
@@ -39,6 +44,11 @@ namespace ARMeilleure.State
 
         public ulong GetPc()
         {
+            if (Optimizations.EnableDebugging)
+            {
+                return GetStorage().CurrentPc;
+            }
+
             // TODO: More precise tracking of PC value.
             return GetStorage().DispatchAddress;
         }
@@ -268,6 +278,11 @@ namespace ARMeilleure.State
             return StorageOffset(ref _dummyStorage, ref _dummyStorage.Running);
         }
 
+        public static int GetCurrentPcOffset()
+        {
+            return StorageOffset(ref _dummyStorage, ref _dummyStorage.CurrentPc);
+        }
+
         private static int StorageOffset<T>(ref NativeCtxStorage storage, ref T target)
         {
             return (int)Unsafe.ByteOffset(ref Unsafe.As<NativeCtxStorage, T>(ref storage), ref target);
diff --git a/src/ARMeilleure/Translation/Translator.cs b/src/ARMeilleure/Translation/Translator.cs
index 343e361a5..351ee34f1 100644
--- a/src/ARMeilleure/Translation/Translator.cs
+++ b/src/ARMeilleure/Translation/Translator.cs
@@ -388,6 +388,11 @@ namespace ARMeilleure.Translation
                     // Return to managed rather than tail call.
                     bool useReturns = Optimizations.EnableDebugging;
 
+                    if (Optimizations.EnableDebugging)
+                    {
+                        EmitPcUpdate(context, block.Address);
+                    }
+
                     InstEmitFlowHelper.EmitVirtualJump(context, Const(block.Address), isReturn: useReturns);
                 }
                 else
@@ -410,6 +415,11 @@ namespace ARMeilleure.Translation
                             }
                         }
 
+                        if (Optimizations.EnableDebugging)
+                        {
+                            EmitPcUpdate(context, opCode.Address);
+                        }
+
                         Operand lblPredicateSkip = default;
 
                         if (context.IsInIfThenBlock && context.CurrentIfThenBlockCond != Condition.Al)
@@ -506,6 +516,14 @@ namespace ARMeilleure.Translation
             context.MarkLabel(lblExit);
         }
 
+        internal static void EmitPcUpdate(EmitterContext context, ulong address)
+        {
+            long currentPcOffs = NativeContext.GetCurrentPcOffset();
+
+            Operand currentPcAddr = context.Add(context.LoadArgument(OperandType.I64, 0), Const(currentPcOffs));
+            context.Store(currentPcAddr, Const(address));
+        }
+
         public void InvalidateJitCacheRegion(ulong address, ulong size)
         {
             ulong[] overlapAddresses = [];