Report errors when hardware breakpoints fail with LLDB

core/adapters/lldbadapter.cpp

@@ -2131,13 +2131,45 @@ void LldbAdapter::EventListener()
 						{
 							// Apply the hardware breakpoint now that process is running and stopped
 							// Check addressing mode and call appropriate variant
+							bool success;
 							if (hwbp.isRelative)
 							{
-								AddHardwareBreakpoint(hwbp.location, hwbp.type, hwbp.size);
+								success = AddHardwareBreakpoint(hwbp.location, hwbp.type, hwbp.size);
 							}
 							else
 							{
-								AddHardwareBreakpoint(hwbp.address, hwbp.type, hwbp.size);
+								success = AddHardwareBreakpoint(hwbp.address, hwbp.type, hwbp.size);
+							}
+
+							if (!success)
+							{
+								uint64_t addr = hwbp.isRelative ?
+									(hwbp.location.offset + m_originalImageBase) : hwbp.address;
+
+								if (hwbp.type == HardwareExecuteBreakpoint)
+								{
+									std::string arch = GetTargetArchitecture();
+									if (arch == "x86_64" || arch == "i386")
+									{
+										LogError("Failed to add hardware execution breakpoint at 0x%" PRIx64
+											". Hardware execution breakpoints are not supported with the LLDB adapter"
+											" on x86/x64 Linux. Consider using a software breakpoint instead."
+											" See https://github.com/Vector35/debugger/issues/957 for details.",
+											addr);
+									}
+									else
+									{
+										LogError("Failed to add hardware execution breakpoint at 0x%" PRIx64
+											". The target may not support hardware breakpoints or all"
+											" hardware breakpoint slots may be in use.", addr);
+									}
+								}
+								else
+								{
+									LogError("Failed to add hardware breakpoint at 0x%" PRIx64
+										". The target may not support hardware breakpoints or all"
+										" hardware breakpoint slots may be in use.", addr);
+								}
 							}
 						}
 						m_deferredHardwareBreakpoints.clear();

core/debuggerstate.cpp

@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 #include <chrono>
+#include <inttypes.h>
 #include <thread>
 #include <utility>
 #include <filesystem>
@@ -1126,15 +1127,25 @@ void DebuggerBreakpoints::Apply()
 		else
 		{
 			// Hardware breakpoints can use either module+offset or absolute address
+			bool success;
 			if (bp.isRelative)
 			{
 				// Use module+offset - adapter will handle resolution
-				m_state->GetAdapter()->AddHardwareBreakpoint(bp.location, bp.type, bp.size);
+				success = m_state->GetAdapter()->AddHardwareBreakpoint(bp.location, bp.type, bp.size);
 			}
 			else
 			{
 				// Use absolute address
-				m_state->GetAdapter()->AddHardwareBreakpoint(bp.address, bp.type, bp.size);
+				success = m_state->GetAdapter()->AddHardwareBreakpoint(bp.address, bp.type, bp.size);
+			}
+
+			if (!success)
+			{
+				uint64_t addr = bp.isRelative ?
+					m_state->GetModules()->RelativeAddressToAbsolute(bp.location) : bp.address;
+				LogError("Failed to add hardware breakpoint at 0x%" PRIx64
+					". The target may not support this type of hardware breakpoint"
+					" or all hardware breakpoint slots may be in use.", addr);
 			}
 		}
 	}

ui/hardwarebreakpointdialog.cpp

@@ -134,6 +134,21 @@ void HardwareBreakpointDialog::addBreakpoint()
 
 	if (m_controller)
 	{
+		// Warn upfront if the user is trying to add a hardware execution breakpoint
+		// with LLDB before debugging -- it will be recorded but will fail silently later
+		if (type == HardwareExecuteBreakpoint
+			&& m_controller->GetAdapterType() == "LLDB"
+			&& !m_controller->IsConnected())
+		{
+			QMessageBox::warning(this, "Hardware Execution Breakpoint Not Supported",
+				"Hardware execution breakpoints are not supported with the LLDB adapter "
+				"on x86/x64 Linux. The breakpoint will be saved but will fail when "
+				"debugging starts.\n\n"
+				"Consider using a software breakpoint instead.\n\n"
+				"See https://github.com/Vector35/debugger/issues/957 for details.");
+			return;
+		}
+
 		bool success = false;
 
 		// Determine if we should use absolute or relative addressing
@@ -159,8 +174,25 @@ void HardwareBreakpointDialog::addBreakpoint()
 		}
 		else
 		{
-			QMessageBox::warning(this, "Failed to Add Breakpoint",
-				"Failed to add hardware breakpoint. The target may not support hardware breakpoints or all hardware breakpoint slots may be in use.");
+			QString message;
+			if (type == HardwareExecuteBreakpoint
+				&& m_controller->GetAdapterType() == "LLDB")
+			{
+				message = "Failed to add hardware execution breakpoint.\n\n"
+					"This is a known issue: LLDB does not support hardware execution "
+					"breakpoints on x86/x64 Linux. Consider using a software breakpoint "
+					"instead.\n\n"
+					"See https://github.com/Vector35/debugger/issues/957 for details.";
+			}
+			else
+			{
+				message = "Failed to add hardware breakpoint.\n\n"
+					"Possible causes:\n"
+					"  - The target does not support this type of hardware breakpoint\n"
+					"  - All hardware breakpoint slots are in use\n"
+					"  - The address is not valid for a hardware breakpoint";
+			}
+			QMessageBox::warning(this, "Failed to Add Breakpoint", message);
 		}
 	}
 }