Add support for TTD in GDB MI adapter (#1019)

Author: xusheng6

core/adapters/gdbmiadapter.cpp

@@ -542,6 +542,27 @@ bool GdbMiAdapter::Connect(const std::string& server, uint32_t port) {
 		}
 	}
 
+	// Detect reverse debugging / TTD support by probing the remote server's qSupported capabilities.
+	// Servers like udbserver and rr advertise ReverseContinue+ and ReverseStep+ in qSupported.
+	m_canReverseContinue = false;
+	m_canReverseStep = false;
+	{
+		std::string qSupportedResponse = InvokeBackendCommand(
+			"maintenance packet qSupported:ReverseContinue+;ReverseStep+");
+		if (!qSupportedResponse.empty())
+		{
+			if (qSupportedResponse.find("ReverseContinue+") != std::string::npos)
+				m_canReverseContinue = true;
+			if (qSupportedResponse.find("ReverseStep+") != std::string::npos)
+				m_canReverseStep = true;
+		}
+
+		if (m_canReverseContinue && m_canReverseStep)
+			LogInfo("Reverse debugging support detected (TTD enabled)");
+		else
+			LogInfo("No reverse debugging support detected");
+	}
+
 	// AFTER we are connected and stopped, populate the cache for the first time.
 	LogInfo("Populating initial state cache...");
 	ScheduleStateRefresh();
@@ -1031,6 +1052,30 @@ bool GdbMiAdapter::StepReturn() {
 	return (m_mi->SendCommand("-exec-finish").command == "running");
 }
 
+bool GdbMiAdapter::GoReverse() {
+	if (!m_mi || m_targetRunningAtomic || !m_canReverseContinue) return false;
+
+	return (m_mi->SendCommand("-exec-continue --reverse").command == "running");
+}
+
+bool GdbMiAdapter::StepIntoReverse() {
+	if (!m_mi || m_targetRunningAtomic || !m_canReverseStep) return false;
+
+	return (m_mi->SendCommand("-exec-step-instruction --reverse").command == "running");
+}
+
+bool GdbMiAdapter::StepOverReverse() {
+	if (!m_mi || m_targetRunningAtomic || !m_canReverseStep) return false;
+
+	return (m_mi->SendCommand("-exec-next-instruction --reverse").command == "running");
+}
+
+bool GdbMiAdapter::StepReturnReverse() {
+	if (!m_mi || m_targetRunningAtomic || !m_canReverseStep) return false;
+
+	return (m_mi->SendCommand("-exec-finish --reverse").command == "running");
+}
+
 uint64_t GdbMiAdapter::GetInstructionOffset() {
 	std::string ipRegisterName;
 	if ((m_remoteArch == "x86") || (m_remoteArch == "i386"))
@@ -1091,9 +1136,10 @@ std::string GdbMiAdapter::GetTargetArchitecture() { return m_remoteArch; }
 bool GdbMiAdapter::SupportFeature(DebugAdapterCapacity feature) {
     switch (feature) {
         case DebugAdapterSupportStepOver: return true;
+        case DebugAdapterSupportStepOverReverse: return m_canReverseContinue && m_canReverseStep;
         case DebugAdapterSupportModules: return true;
         case DebugAdapterSupportThreads: return true;
-        case DebugAdapterSupportTTD: return false;
+        case DebugAdapterSupportTTD: return m_canReverseContinue && m_canReverseStep;
         default: return false;
     }
 }

core/adapters/gdbmiadapter.h

@@ -14,6 +14,10 @@ class GdbMiAdapter : public BinaryNinjaDebugger::DebugAdapter
     bool m_connected = false;
     std::string m_remoteArch;
     std::vector<std::string> m_registerNames; // In GDB's order
+
+    // TTD / reverse debugging capability flags (set during Connect)
+    bool m_canReverseContinue = false;
+    bool m_canReverseStep = false;
     BinaryNinjaDebugger::DebugStopReason m_lastStopReason;
     std::atomic<bool> m_targetRunningAtomic{false};
     uint64_t m_exitCode = 0;
@@ -100,6 +104,11 @@ class GdbMiAdapter : public BinaryNinjaDebugger::DebugAdapter
     bool StepOver() override;
 	bool StepReturn() override;
 
+    bool GoReverse() override;
+    bool StepIntoReverse() override;
+    bool StepOverReverse() override;
+    bool StepReturnReverse() override;
+
 	std::uint32_t GetActivePID() override { return 0; }
 
     std::string InvokeBackendCommand(const std::string& command) override;

core/debuggercontroller.cpp

@@ -501,10 +501,6 @@ bool DebuggerController::CreateDebugAdapter()
 	// Binary View object
 	m_adapter->SetController(this);
 
-	m_adapterSupportsStepOver = m_adapter->SupportFeature(DebugAdapterSupportStepOver);
-	m_adapterSupportsStepOverReverse = m_adapter->SupportFeature(DebugAdapterSupportStepOverReverse);
-	m_adapterSupportsTTD = m_adapter->SupportFeature(DebugAdapterSupportTTD);
-
 	ApplyBreakpoints();
 
 	// Forward the DebuggerEvent from the adapters to the controller
@@ -1688,7 +1684,7 @@ DebugStopReason DebuggerController::StepOverAndWaitInternal()
 {
 	m_userRequestedBreak = false;
 
-	if (m_adapterSupportsStepOver)
+	if (m_adapter && m_adapter->SupportFeature(DebugAdapterSupportStepOver))
 	{
 		return ExecuteAdapterAndWait(DebugAdapterStepOver);
 	}
@@ -1703,7 +1699,7 @@ DebugStopReason DebuggerController::StepOverReverseAndWaitInternal()
 {
 	m_userRequestedBreak = false;
 
-	if (m_adapterSupportsStepOverReverse)
+	if (m_adapter && m_adapter->SupportFeature(DebugAdapterSupportStepOverReverse))
 	{
 		return ExecuteAdapterAndWait(DebugAdapterStepOverReverse);
 	}
@@ -3147,7 +3143,7 @@ std::vector<TTDEvent> DebuggerController::GetAllTTDEvents()
 
 void DebuggerController::RecordTTDPosition()
 {
-	if (!m_adapterSupportsTTD || !m_adapter || m_suppressTTDPositionRecording)
+	if (!m_adapter || !m_adapter->SupportFeature(DebugAdapterSupportTTD) || m_suppressTTDPositionRecording)
 		return;
 
 	TTDPosition position = m_adapter->GetCurrentTTDPosition();
@@ -3199,13 +3195,13 @@ bool DebuggerController::TTDNavigateForward()
 
 bool DebuggerController::CanTTDNavigateBack() const
 {
-	return m_adapterSupportsTTD && m_ttdPositionHistoryIndex > 0;
+	return m_adapter && m_adapter->SupportFeature(DebugAdapterSupportTTD) && m_ttdPositionHistoryIndex > 0;
 }
 
 
 bool DebuggerController::CanTTDNavigateForward() const
 {
-	return m_adapterSupportsTTD
+	return m_adapter && m_adapter->SupportFeature(DebugAdapterSupportTTD)
 		&& m_ttdPositionHistoryIndex >= 0
 		&& m_ttdPositionHistoryIndex < static_cast<int>(m_ttdPositionHistory.size()) - 1;
 }

core/debuggercontroller.h

@@ -189,12 +189,6 @@ namespace BinaryNinjaDebugger {
 
 		void DetectLoadedModule();
 
-		bool m_adapterSupportsStepOver = false;
-		bool m_adapterSupportsStepOverReverse = false;
-		// bool m_adapterSupportsModules = false;
-		// bool m_adapterSupportsThreads = false;
-		bool m_adapterSupportsTTD = false;
-
 		std::mutex m_eventsMutex;
 		std::condition_variable m_cv;
 		std::queue<std::shared_ptr<PendingEvent>> m_eventQueue;