Update stepping through MulticastDelegate under the Debugger (#108414)

* macOS stepping with multicast delegates

* remove one call of  MulticastDebuggerTraceHelper

* change int to INT_PTR

* change to QCall and optimize

* styling and cleanup

src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs

@@ -1583,8 +1583,14 @@ internal static void ValidateObject(object obj, IntPtr pMD)
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern IntPtr GetStubContext();
 
-        [MethodImpl(MethodImplOptions.InternalCall)]
-        internal static extern void MulticastDebuggerTraceHelper(object o, int count);
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        internal static void MulticastDebuggerTraceHelper(object o, int count)
+        {
+            MulticastDebuggerTraceHelperQCall(ObjectHandleOnStack.Create(ref o), count);
+        }
+
+        [LibraryImport(RuntimeHelpers.QCall, EntryPoint="StubHelpers_MulticastDebuggerTraceHelper")]
+        private static partial void MulticastDebuggerTraceHelperQCall(ObjectHandleOnStack obj, int count);
 
         [Intrinsic]
         [MethodImpl(MethodImplOptions.InternalCall)]

src/coreclr/debug/ee/controller.cpp

@@ -943,7 +943,8 @@ DebuggerController::DebuggerController(Thread * pThread, AppDomain * pAppDomain)
     m_unwindFP(LEAF_MOST_FRAME),
     m_eventQueuedCount(0),
     m_deleted(false),
-    m_fEnableMethodEnter(false)
+    m_fEnableMethodEnter(false),
+    m_multicastDelegateHelper(false)
 {
     CONTRACTL
     {
@@ -1133,6 +1134,8 @@ void DebuggerController::DisableAll()
             DisableTraceCall();
         if (m_fEnableMethodEnter)
             DisableMethodEnter();
+        if (m_multicastDelegateHelper)
+            DisableMultiCastDelegate();
     }
 }
 
@@ -2279,6 +2282,7 @@ static bool _AddrIsJITHelper(PCODE addr)
 // method & return true.
 //
 // Return true if we set a patch, else false
+#ifndef DACCESS_COMPILE
 bool DebuggerController::PatchTrace(TraceDestination *trace,
                                     FramePointer fp,
                                     bool fStopInUnmanaged)
@@ -2364,7 +2368,7 @@ bool DebuggerController::PatchTrace(TraceDestination *trace,
 
     case TRACE_FRAME_PUSH:
         LOG((LF_CORDB, LL_INFO10000,
-             "Setting frame patch at 0x%p(%p)\n", trace->GetAddress(), fp.GetSPValue()));
+             "Setting frame patch at %p(%p)\n", trace->GetAddress(), fp.GetSPValue()));
 
         AddAndActivateNativePatchForAddress((CORDB_ADDRESS_TYPE *)trace->GetAddress(),
                  fp,
@@ -2374,13 +2378,12 @@ bool DebuggerController::PatchTrace(TraceDestination *trace,
 
     case TRACE_MGR_PUSH:
         LOG((LF_CORDB, LL_INFO10000,
-             "Setting frame patch (TRACE_MGR_PUSH) at 0x%p(%p)\n",
-             trace->GetAddress(), fp.GetSPValue()));
-
+            "Setting frame patch (TRACE_MGR_PUSH) at %p(%p)\n",
+            trace->GetAddress(), fp.GetSPValue()));
         dcp = AddAndActivateNativePatchForAddress((CORDB_ADDRESS_TYPE *)trace->GetAddress(),
-                       LEAF_MOST_FRAME, // But Mgr_push can't have fp affinity!
-                       TRUE,
-                       DPT_DEFAULT_TRACE_TYPE); // TRACE_OTHER
+                    LEAF_MOST_FRAME, // But Mgr_push can't have fp affinity!
+                    TRUE,
+                    DPT_DEFAULT_TRACE_TYPE); // TRACE_OTHER
         // Now copy over the trace field since TriggerPatch will expect this
         // to be set for this case.
         if (dcp != NULL)
@@ -2390,6 +2393,10 @@ bool DebuggerController::PatchTrace(TraceDestination *trace,
 
         return true;
 
+    case TRACE_MULTICAST_DELEGATE_HELPER:
+        EnableMultiCastDelegate();
+        return true;
+
     case TRACE_OTHER:
         LOG((LF_CORDB, LL_INFO10000,
              "Can't set a trace patch for TRACE_OTHER...\n"));
@@ -2400,6 +2407,7 @@ bool DebuggerController::PatchTrace(TraceDestination *trace,
         return false;
     }
 }
+#endif
 
 //-----------------------------------------------------------------------------
 // Checks if the patch matches the context + thread.
@@ -3879,6 +3887,73 @@ void DebuggerController::DispatchMethodEnter(void * pIP, FramePointer fp)
 
 }
 
+void DebuggerController::EnableMultiCastDelegate()
+{
+    CONTRACTL
+    {
+        NOTHROW;
+        GC_NOTRIGGER;
+    }
+    CONTRACTL_END;
+
+    ControllerLockHolder chController;
+    if (!m_multicastDelegateHelper)
+    {
+        LOG((LF_CORDB, LL_INFO1000000, "DC::EnableMultiCastDel, this=%p, previously disabled\n", this));
+        m_multicastDelegateHelper = true;
+        g_multicastDelegateTraceActiveCount += 1;
+    }
+    else
+    {
+        LOG((LF_CORDB, LL_INFO1000000, "DC::EnableMultiCastDel, this=%p, already set\n", this));
+    }
+}
+
+void DebuggerController::DisableMultiCastDelegate()
+{
+    CONTRACTL
+    {
+        NOTHROW;
+        GC_NOTRIGGER;
+    }
+    CONTRACTL_END;
+
+    ControllerLockHolder chController;
+    if (m_multicastDelegateHelper)
+    {
+        LOG((LF_CORDB, LL_INFO10000, "DC::DisableMultiCastDelegate, this=%p, previously set\n", this));
+        m_multicastDelegateHelper = false;
+        g_multicastDelegateTraceActiveCount -= 1;
+    }
+    else
+    {
+        LOG((LF_CORDB, LL_INFO10000, "DC::DisableMultiCastDelegate, this=%p, already disabled\n", this));
+    }
+}
+
+// Loop through controllers and dispatch TriggerMulticastDelegate
+void DebuggerController::DispatchMulticastDelegate(DELEGATEREF pbDel, INT32 countDel)
+{
+    LOG((LF_CORDB, LL_INFO10000, "DC::DispatchMulticastDelegate\n"));
+
+    Thread * pThread = g_pEEInterface->GetThread();
+    _ASSERTE(pThread  != NULL);
+
+    ControllerLockHolder lockController;
+
+    DebuggerController *p = g_controllers;
+    while (p != NULL)
+    {
+        if (p->m_multicastDelegateHelper)
+        {
+            if ((p->GetThread() == NULL) || (p->GetThread() == pThread))
+            {
+                p->TriggerMulticastDelegate(pbDel, countDel);
+            }
+        }
+        p = p->m_next;
+    }
+}
 //
 // AddProtection adds page protection to (at least) the given range of
 // addresses
@@ -4023,6 +4098,10 @@ void DebuggerController::DispatchFuncEvalExit(Thread * thread)
 
 
 }
+void DebuggerController::TriggerMulticastDelegate(DELEGATEREF pDel, INT32 delegateCount)
+{
+    _ASSERTE(!"This code should be unreachable. If your controller enables MulticastDelegateHelper events,it should also override this callback to do something useful when the event arrives.");
+}
 
 
 #ifdef _DEBUG
@@ -6283,7 +6362,7 @@ void DebuggerStepper::TrapStepOut(ControllerStackInfo *info, bool fForceTraditio
                 && g_pEEInterface->FollowTrace(&trace)
                 && PatchTrace(&trace, info->m_activeFrame.fp,
                               true))
-                break;
+                continue;
         }
         else if (info->m_activeFrame.md != nullptr && info->m_activeFrame.md->IsILStub() &&
                  info->m_activeFrame.md->AsDynamicMethodDesc()->GetILStubType() == DynamicMethodDesc::StubTailCallCallTarget)
@@ -7553,6 +7632,21 @@ void DebuggerStepper::TriggerUnwind(Thread *thread,
     m_reason = unwindReason;
 }
 
+void DebuggerStepper::TriggerMulticastDelegate(DELEGATEREF pDel, INT32 delegateCount)
+{
+    TraceDestination trace;
+    FramePointer fp = LEAF_MOST_FRAME;
+
+    PTRARRAYREF pDelInvocationList = (PTRARRAYREF) pDel->GetInvocationList();
+    DELEGATEREF pCurrentInvokeDel = (DELEGATEREF) pDelInvocationList->GetAt(delegateCount);
+
+    StubLinkStubManager::TraceDelegateObject((BYTE*)OBJECTREFToObject(pCurrentInvokeDel), &trace);
+
+    g_pEEInterface->FollowTrace(&trace);
+    //fStopInUnmanaged only matters for TRACE_UNMANAGED
+    PatchTrace(&trace, fp, /*fStopInUnmanaged*/false);
+    this->DisableMultiCastDelegate();
+}
 
 // Prepare for sending an event.
 // This is called 1:1 w/ SendEvent, but this method can be called in a GC_TRIGGERABLE context

src/coreclr/debug/ee/controller.h

@@ -1089,6 +1089,7 @@ class DebuggerController
     // pIP is the ip right after the prolog of the method we've entered.
     // fp is the frame pointer for that method.
     static void DispatchMethodEnter(void * pIP, FramePointer fp);
+    static void DispatchMulticastDelegate(DELEGATEREF pbDel, INT32 countDel);
 
 
     // Delete any patches that exist for a specific module and optionally a specific AppDomain.
@@ -1299,6 +1300,9 @@ class DebuggerController
     void EnableMethodEnter();
     void DisableMethodEnter();
 
+    void EnableMultiCastDelegate();
+    void DisableMultiCastDelegate();
+
     void DisableAll();
 
     virtual DEBUGGER_CONTROLLER_TYPE GetDCType( void )
@@ -1398,6 +1402,7 @@ class DebuggerController
                                     const BYTE * ip,
                                     FramePointer fp);
 
+    virtual void TriggerMulticastDelegate(DELEGATEREF pDel, INT32 delegateCount);
 
     // Send the managed debug event.
     // This is called after TriggerPatch/TriggerSingleStep actually trigger.
@@ -1437,6 +1442,7 @@ class DebuggerController
     int                 m_eventQueuedCount;
     bool                m_deleted;
     bool                m_fEnableMethodEnter;
+    bool                m_multicastDelegateHelper;
 
 #endif // !DACCESS_COMPILE
 };
@@ -1638,7 +1644,7 @@ class DebuggerStepper : public DebuggerController
 
 
     virtual void TriggerMethodEnter(Thread * thread, DebuggerJitInfo * dji, const BYTE * ip, FramePointer fp);
-
+    void TriggerMulticastDelegate(DELEGATEREF pDel, INT32 delegateCount);
 
     void ResetRange();
 

src/coreclr/debug/ee/debugger.cpp

@@ -26,6 +26,7 @@
 #include "../../vm/dwreport.h"
 #include "../../vm/eepolicy.h"
 #include "../../vm/excep.h"
+
 #if defined(FEATURE_DBGIPC_TRANSPORT_VM)
 #include "dbgtransportsession.h"
 #endif // FEATURE_DBGIPC_TRANSPORT_VM
@@ -12588,7 +12589,7 @@ bool Debugger::IsThreadAtSafePlace(Thread *thread)
     // any thread handling a SO is not at a safe place.
     // NOTE: don't check for thread->IsExceptionInProgress(), SO has special handling
     // that directly sets the last thrown object without ever creating a tracker.
-    // (Tracker is what thread->IsExceptionInProgress() checks for)   
+    // (Tracker is what thread->IsExceptionInProgress() checks for)
     if (g_pEEInterface->GetThreadException(thread) == CLRException::GetPreallocatedStackOverflowExceptionHandle())
     {
         return false;
@@ -16775,6 +16776,12 @@ BOOL Debugger::IsOutOfProcessSetContextEnabled()
 }
 #endif // OUT_OF_PROCESS_SETTHREADCONTEXT
 #endif // DACCESS_COMPILE
+#ifndef DACCESS_COMPILE
+void Debugger::MulticastTraceNextStep(DELEGATEREF pbDel, INT32 count)
+{
+    DebuggerController::DispatchMulticastDelegate(pbDel, count);
+}
+#endif //DACCESS_COMPILE
 
 #endif //DEBUGGING_SUPPORTED
 

src/coreclr/debug/ee/debugger.h

@@ -2610,6 +2610,9 @@ class Debugger : public DebugInterface
     bool ThisIsHelperThread(void);
 
     HRESULT ReDaclEvents(PSECURITY_DESCRIPTOR securityDescriptor);
+#ifndef DACCESS_COMPILE
+    void MulticastTraceNextStep(DELEGATEREF pbDel, INT32 count);
+#endif
 
 #ifdef DACCESS_COMPILE
     virtual void EnumMemoryRegions(CLRDataEnumMemoryFlags flags);

src/coreclr/vm/comdelegate.cpp

@@ -2137,18 +2137,30 @@ extern "C" PCODE QCALLTYPE Delegate_GetMulticastInvokeSlow(MethodTable* pDelegat
             dwReturnValNum = pCode->NewLocal(sig.GetRetTypeHandleNT());
 
         ILCodeLabel *nextDelegate = pCode->NewCodeLabel();
-        ILCodeLabel *checkCount = pCode->NewCodeLabel();
 
         // initialize counter
         pCode->EmitLDC(0);
         pCode->EmitSTLOC(dwLoopCounterNum);
 
-        // Make the shape of the loop similar to what C# compiler emits
-        pCode->EmitBR(checkCount);
-
         //Label_nextDelegate:
         pCode->EmitLabel(nextDelegate);
 
+#ifdef DEBUGGING_SUPPORTED
+        ILCodeLabel *invokeTraceHelper = pCode->NewCodeLabel();
+        ILCodeLabel *debuggerCheckEnd = pCode->NewCodeLabel();
+
+        // Call MulticastDebuggerTraceHelper only if we have a controller subscribing to the event
+        pCode->EmitLDC((DWORD_PTR)&g_multicastDelegateTraceActiveCount);
+        pCode->EmitCONV_I();
+        pCode->EmitLDIND_I4();
+        // g_multicastDelegateTraceActiveCount != 0
+        pCode->EmitLDC(0);
+        pCode->EmitCEQ();
+        pCode->EmitBRFALSE(invokeTraceHelper);
+
+        pCode->EmitLabel(debuggerCheckEnd);
+#endif // DEBUGGING_SUPPORTED
+
         // Load next delegate from array using LoopCounter as index
         pCode->EmitLoadThis();
         pCode->EmitLDFLD(pCode->GetToken(CoreLibBinder::GetField(FIELD__MULTICAST_DELEGATE__INVOCATION_LIST)));
@@ -2172,26 +2184,6 @@ extern "C" PCODE QCALLTYPE Delegate_GetMulticastInvokeSlow(MethodTable* pDelegat
         pCode->EmitADD();
         pCode->EmitSTLOC(dwLoopCounterNum);
 
-        //Label_checkCount
-        pCode->EmitLabel(checkCount);
-
-#ifdef DEBUGGING_SUPPORTED
-        ILCodeLabel *invokeTraceHelper = pCode->NewCodeLabel();
-        ILCodeLabel *debuggerCheckEnd = pCode->NewCodeLabel();
-
-        // Call MulticastDebuggerTraceHelper only if any debugger is attached
-        pCode->EmitLDC((DWORD_PTR)&g_CORDebuggerControlFlags);
-        pCode->EmitCONV_I();
-        pCode->EmitLDIND_I4();
-
-        // (g_CORDebuggerControlFlags & DBCF_ATTACHED) != 0
-        pCode->EmitLDC(DBCF_ATTACHED);
-        pCode->EmitAND();
-        pCode->EmitBRTRUE(invokeTraceHelper);
-
-        pCode->EmitLabel(debuggerCheckEnd);
-#endif // DEBUGGING_SUPPORTED
-
         // compare LoopCounter with InvocationCount. If less then branch to nextDelegate
         pCode->EmitLDLOC(dwLoopCounterNum);
         pCode->EmitLoadThis();

src/coreclr/vm/dbginterface.h

@@ -408,6 +408,7 @@ class DebugInterface
 #ifndef DACCESS_COMPILE
     virtual HRESULT DeoptimizeMethod(Module* pModule, mdMethodDef methodDef) = 0;
     virtual HRESULT IsMethodDeoptimized(Module *pModule, mdMethodDef methodDef, BOOL *pResult) = 0;
+    virtual void MulticastTraceNextStep(DELEGATEREF pbDel, INT32 count) = 0;
 #endif //DACCESS_COMPILE
 };
 

src/coreclr/vm/ecalllist.h

@@ -386,7 +386,6 @@ FCFuncStart(gStubHelperFuncs)
     FCFuncElement("CalcVaListSize", StubHelpers::CalcVaListSize)
     FCFuncElement("LogPinnedArgument", StubHelpers::LogPinnedArgument)
     FCFuncElement("GetStubContext", StubHelpers::GetStubContext)
-    FCFuncElement("MulticastDebuggerTraceHelper", StubHelpers::MulticastDebuggerTraceHelper)
     FCFuncElement("NextCallReturnAddress", StubHelpers::NextCallReturnAddress)
 FCFuncEnd()
 

src/coreclr/vm/qcallentrypoints.cpp

@@ -466,6 +466,7 @@ static const Entry s_QCall[] =
     DllImportEntry(StubHelpers_MarshalToUnmanagedVaList)
     DllImportEntry(StubHelpers_ValidateObject)
     DllImportEntry(StubHelpers_ValidateByref)
+    DllImportEntry(StubHelpers_MulticastDebuggerTraceHelper)
 #ifdef PROFILING_SUPPORTED
     DllImportEntry(StubHelpers_ProfilerBeginTransitionCallback)
     DllImportEntry(StubHelpers_ProfilerEndTransitionCallback)