SymbolMap: route remaining GUI-thread callers, remove internal locking

Windows/MainWindowMenu.cpp's Load/Save/Clear Symbol Map menu actions
mutated g_symbolMap directly from the WinMain thread; route them through
Core_RunOnCPUThread like the rest of the debugger. Windows/MainWindow.cpp's
WM_USER_GET_MODULE_INFO handler read it directly too; guard with
g_frameMutex. Windows/main.cpp's SortSymbols() calls turn out to already be
safe as-is - both notifications that trigger them (BOOT_DONE,
SYMBOL_MAP_UPDATED) are only ever fired from the CPU/NativeFrame thread -
so just fix the stale comment claiming reliance on the (now removed)
internal lock.

With those covered, every remaining caller is either on the CPU/NativeFrame
thread already or routes through Core_RunOnCPUThread/g_frameMutex, so
SymbolMap's internal recursive_mutex is redundant - remove it and all ~40
lock_guard call sites. Qt's mainwindow.cpp still pokes at g_symbolMap
directly and unguarded (a pre-existing issue, out of scope - Qt isn't a
maintained backend), but removing the lock doesn't change its public API,
so it still builds.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Hqm11k99viLfbJm2MkH4BH

Windows/MainWindow.cpp

@@ -725,8 +725,12 @@ namespace MainWindow {
 			{
 				return 0;
 			}
-			// Get all modules from symbol map
-			auto modules = g_symbolMap->getAllModules();
+			// Get all modules from symbol map. Reading it here on the GUI thread would otherwise
+			// race with the CPU thread - hold g_frameMutex for the duration of the read, which
+			// NativeFrame() also holds while it's actually touching that state. See g_frameMutex
+			// in Core.h.
+			std::lock_guard<std::mutex> frameGuard(g_frameMutex);
+			std::vector<LoadedModuleInfo> modules = g_symbolMap->getAllModules();
 			for (const auto& module : modules)
 			{
 				if (module.name == moduleName)

Windows/MainWindowMenu.cpp

@@ -769,34 +769,41 @@ namespace MainWindow {
 			break;
 		}
 
+		// g_symbolMap access below is routed through Core_RunOnCPUThread() instead of poking at it
+		// directly from this GUI thread - see Core_RunOnCPUThread() in Core.h. The file-browse
+		// dialogs are modal, so they stay outside the queued callback; NotifyDebuggerMapLoaded()
+		// also stays outside, since it locks g_frameMutex internally (CDisasm/CMemoryDlg's
+		// NotifyMapLoaded()) and Core_RunOnCPUThread's queue can be drained from inside a
+		// g_frameMutex-locked NativeFrame() span, so calling it from within the lambda could
+		// deadlock.
 		case ID_DEBUG_LOADMAPFILE:
 			if (W32Util::BrowseForFileName(true, hWnd, L"Load .ppmap", nullptr, nullptr, L"Maps\0*.ppmap\0All files\0*.*\0\0", L"ppmap", fn)) {
-				g_symbolMap->LoadSymbolMap(Path(fn));
+				Core_RunOnCPUThread([&] { g_symbolMap->LoadSymbolMap(Path(fn)); });
 				NotifyDebuggerMapLoaded();
 			}
 			break;
 
 		case ID_DEBUG_SAVEMAPFILE:
 			if (W32Util::BrowseForFileName(false, hWnd, L"Save .ppmap", nullptr, L"map.ppmap", L"Maps\0*.ppmap\0All files\0*.*\0\0", L"ppmap", fn)) {
-				g_symbolMap->SaveSymbolMap(Path(fn));
+				Core_RunOnCPUThread([&] { g_symbolMap->SaveSymbolMap(Path(fn)); });
 			}
 			break;
 
 		case ID_DEBUG_LOADSYMFILE:
 			if (W32Util::BrowseForFileName(true, hWnd, L"Load .sym", nullptr, nullptr, L"Symbols\0*.sym\0All files\0*.*\0\0", L"sym", fn)) {
-				g_symbolMap->LoadNocashSym(Path(fn));
+				Core_RunOnCPUThread([&] { g_symbolMap->LoadNocashSym(Path(fn)); });
 				NotifyDebuggerMapLoaded();
 			}
 			break;
 
 		case ID_DEBUG_SAVESYMFILE:
 			if (W32Util::BrowseForFileName(false, hWnd, L"Save .sym", nullptr, L"symbols.sym", L"Symbols\0*.sym\0All files\0*.*\0\0", L"sym", fn)) {
-				g_symbolMap->SaveNocashSym(Path(fn));
+				Core_RunOnCPUThread([&] { g_symbolMap->SaveNocashSym(Path(fn)); });
 			}
 			break;
 
 		case ID_DEBUG_RESETSYMBOLTABLE:
-			g_symbolMap->Clear();
+			Core_RunOnCPUThread([&] { g_symbolMap->Clear(); });
 			NotifyDebuggerMapLoaded();
 			break;
 

Windows/main.cpp

@@ -508,7 +508,7 @@ void System_Notify(SystemNotification notification) {
 	case SystemNotification::BOOT_DONE:
 	{
 		if (g_symbolMap)
-			g_symbolMap->SortSymbols();  // internal locking is performed here
+			g_symbolMap->SortSymbols();  // Always fired from the CPU/NativeFrame thread, see AGENTS.md
 		PostMessage(MainWindow::GetHWND(), WM_USER + 1, 0, 0);
 
 		if (Achievements::HardcoreModeActive()) {
@@ -548,7 +548,7 @@ void System_Notify(SystemNotification notification) {
 
 	case SystemNotification::SYMBOL_MAP_UPDATED:
 		if (g_symbolMap)
-			g_symbolMap->SortSymbols();  // internal locking is performed here
+			g_symbolMap->SortSymbols();  // Always fired from the CPU/NativeFrame thread, see AGENTS.md
 		PostMessage(MainWindow::GetHWND(), WM_USER + 1, 0, 0);
 		break;