Place breakpoint at luaD_throw only when break is expected there

This fixes slowdown of Lua coroutines and other uses of luaD_throw for non-error cases

Author: WheretIB

LuaDkmDebuggerComponent/AttachmentHelpers.cs

@@ -424,7 +424,7 @@ internal static ulong FindVariableAddress(DkmNativeModuleInstance nativeModuleIn
             return 0;
         }
 
-        internal static Guid? CreateTargetFunctionBreakpointAtAddress(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, ulong address)
+        internal static DkmRuntimeInstructionBreakpoint CreateTargetFunctionBreakpointObjectAtAddress(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, ulong address, bool enabled)
         {
             if (address != 0)
             {
@@ -434,9 +434,10 @@ internal static ulong FindVariableAddress(DkmNativeModuleInstance nativeModuleIn
 
                 var breakpoint = DkmRuntimeInstructionBreakpoint.Create(Guids.luaSupportBreakpointGuid, null, nativeAddress, false, null);
 
-                breakpoint.Enable();
+                if (enabled)
+                    breakpoint.Enable();
 
-                return breakpoint.UniqueId;
+                return breakpoint;
             }
             else
             {
@@ -446,7 +447,17 @@ internal static ulong FindVariableAddress(DkmNativeModuleInstance nativeModuleIn
             return null;
         }
 
-        internal static Guid? CreateTargetFunctionBreakpointAtDebugStart(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, out ulong breakAddress)
+        internal static Guid? CreateTargetFunctionBreakpointAtAddress(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, ulong address)
+        {
+            DkmRuntimeInstructionBreakpoint breakpoint = CreateTargetFunctionBreakpointObjectAtAddress(process, moduleWithLoadedLua, name, desc, address, true);
+
+            if (breakpoint != null)
+                return breakpoint.UniqueId;
+
+            return null;
+        }
+
+        internal static DkmRuntimeInstructionBreakpoint CreateTargetFunctionBreakpointObjectAtDebugStart(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, out ulong breakAddress, bool enabled)
         {
             var address = TryGetFunctionAddressAtDebugStart(moduleWithLoadedLua, name, out string error);
 
@@ -458,10 +469,11 @@ internal static ulong FindVariableAddress(DkmNativeModuleInstance nativeModuleIn
 
                 var breakpoint = DkmRuntimeInstructionBreakpoint.Create(Guids.luaSupportBreakpointGuid, null, nativeAddress, false, null);
 
-                breakpoint.Enable();
+                if (enabled)
+                    breakpoint.Enable();
 
                 breakAddress = address.Value;
-                return breakpoint.UniqueId;
+                return breakpoint;
             }
             else
             {
@@ -472,6 +484,16 @@ internal static ulong FindVariableAddress(DkmNativeModuleInstance nativeModuleIn
             return null;
         }
 
+        internal static Guid? CreateTargetFunctionBreakpointAtDebugStart(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, out ulong breakAddress)
+        {
+            DkmRuntimeInstructionBreakpoint breakpoint = CreateTargetFunctionBreakpointObjectAtDebugStart(process, moduleWithLoadedLua, name, desc, out breakAddress, true);
+
+            if (breakpoint != null)
+                return breakpoint.UniqueId;
+
+            return null;
+        }
+
         internal static Guid? CreateTargetFunctionBreakpointAtDebugEnd(DkmProcess process, DkmNativeModuleInstance moduleWithLoadedLua, string name, string desc, out ulong breakAddress)
         {
             var address = TryGetFunctionAddressAtDebugEnd(moduleWithLoadedLua, name, out string error);

LuaDkmDebuggerComponent/LocalComponent.cs

@@ -100,11 +100,10 @@ internal class LuaLocalProcessData : DkmDataItem
         public Guid breakpointLuaLoad;
 
         // Two-stage Lua exception handling
-        public bool captureNextThrow = false;
         public Guid breakpointLuaBreakError;
         public Guid breakpointLuaRuntimeError;
         public ulong breakpointLuaThrowAddress = 0;
-        public Guid breakpointLuaThrow;
+        public DkmRuntimeInstructionBreakpoint breakpointLuaThrow;
 
         public Guid breakpointLuaHelperInitialized;
 
@@ -2645,11 +2644,11 @@ void IDkmModuleInstanceLoadNotification.OnModuleInstanceLoad(DkmModuleInstance m
                     if (processData.luaLocations != null)
                     {
                         processData.breakpointLuaThrowAddress = processData.luaLocations.luaThrow;
-                        processData.breakpointLuaThrow = AttachmentHelpers.CreateTargetFunctionBreakpointAtAddress(process, processData.moduleWithLoadedLua, "luaD_throw", "Lua script error", processData.luaLocations.luaThrow).GetValueOrDefault(Guid.Empty);
+                        processData.breakpointLuaThrow = AttachmentHelpers.CreateTargetFunctionBreakpointObjectAtAddress(process, processData.moduleWithLoadedLua, "luaD_throw", "Lua script error", processData.luaLocations.luaThrow, false);
                     }
                     else
                     {
-                        processData.breakpointLuaThrow = AttachmentHelpers.CreateTargetFunctionBreakpointAtDebugStart(process, processData.moduleWithLoadedLua, "luaD_throw", "Lua script error", out processData.breakpointLuaThrowAddress).GetValueOrDefault(Guid.Empty);
+                        processData.breakpointLuaThrow = AttachmentHelpers.CreateTargetFunctionBreakpointObjectAtDebugStart(process, processData.moduleWithLoadedLua, "luaD_throw", "Lua script error", out processData.breakpointLuaThrowAddress, false);
                     }
 
                     string assemblyFolder = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
@@ -3248,20 +3247,14 @@ DkmCustomMessage IDkmCustomMessageCallbackReceiver.SendHigher(DkmCustomMessage c
 
                     log.Debug("Enabling a trap at next luaD_throw");
 
-                    processData.captureNextThrow = true;
+                    if (processData.breakpointLuaThrow != null)
+                        processData.breakpointLuaThrow.Enable();
                 }
-                else if (data.breakpointId == processData.breakpointLuaThrow)
+                else if (processData.breakpointLuaThrow != null && data.breakpointId == processData.breakpointLuaThrow.UniqueId)
                 {
                     log.Debug("Detected Lua exception throw");
 
-                    if (!processData.captureNextThrow)
-                    {
-                        log.Debug("Capture is not enabled");
-
-                        return null;
-                    }
-
-                    processData.captureNextThrow = false;
+                    processData.breakpointLuaThrow.Disable();
 
                     var inspectionSession = EvaluationHelpers.CreateInspectionSession(process, thread, data, out DkmStackWalkFrame frame);