On Windows, osd_break_into_debugger() will now dump a stack crawl

if there's no debugger attached. This means that asserts should have
a full crawl now, for easier debugging.

src/osd/windows/winmain.c

@@ -118,11 +118,12 @@ class stack_walker
 {
 public:
 	stack_walker();
-
+	
 	FPTR ip() const { return m_stackframe.AddrPC.Offset; }
 	FPTR sp() const { return m_stackframe.AddrStack.Offset; }
 	FPTR frame() const { return m_stackframe.AddrFrame.Offset; }
 
+	bool reset();
 	void reset(CONTEXT &context, HANDLE thread);
 	bool unwind();
 
@@ -138,6 +139,7 @@ private:
 	dynamic_bind<BOOL (WINAPI *)(HANDLE, LPCTSTR, BOOL)> m_sym_initialize;
 	dynamic_bind<PVOID (WINAPI *)(HANDLE, DWORD64)> m_sym_function_table_access_64;
 	dynamic_bind<DWORD64 (WINAPI *)(HANDLE, DWORD64)> m_sym_get_module_base_64;
+	dynamic_bind<VOID (WINAPI *)(PCONTEXT)> m_rtl_capture_context;
 
 	static bool		s_initialized;
 };
@@ -392,11 +394,15 @@ int main(int argc, char *argv[])
 	// allocate symbols
 	symbol_manager local_symbols(argv[0]);
 	symbols = &local_symbols;
-
+	
 	// set up exception handling
 	pass_thru_filter = SetUnhandledExceptionFilter(exception_filter);
 	SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
 
+	// enable stack crawls for asserts
+	extern void (*s_debugger_stack_crawler)();
+	s_debugger_stack_crawler = winmain_dump_stack;
+
 	// if we're a GUI app, out errors to message boxes
 	if (win_is_gui_application() || is_double_click_start(argc))
 	{
@@ -582,6 +588,23 @@ static void osd_exit(running_machine &machine)
 }
 
 
+//============================================================
+//  winmain_dump_stack
+//============================================================
+
+void winmain_dump_stack()
+{
+	// set up the stack walker
+	stack_walker walker;
+	if (!walker.reset())
+		return;
+
+	// walk the stack
+	while (walker.unwind())
+		fprintf(stderr, "  %p: %p%s\n", (void *)walker.frame(), (void *)walker.ip(), (symbols == NULL) ? "" : symbols->symbol_for_address(walker.ip()));
+}
+
+
 //============================================================
 //  check_for_double_click_start
 //============================================================
@@ -755,14 +778,13 @@ static LONG WINAPI exception_filter(struct _EXCEPTION_POINTERS *info)
 
 	// walk the stack
 	while (walker.unwind())
-		fprintf(stderr, "  %p: %p%s\n", (void *)walker.frame(), (void *)walker.ip(), symbols->symbol_for_address(walker.ip()));
+		fprintf(stderr, "  %p: %p%s\n", (void *)walker.frame(), (void *)walker.ip(), (symbols == NULL) ? "" : symbols->symbol_for_address(walker.ip()));
 
 	// exit
 	return EXCEPTION_CONTINUE_SEARCH;
 }
 
 
-
 //**************************************************************************
 //  STACK WALKER
 //**************************************************************************
@@ -778,7 +800,8 @@ stack_walker::stack_walker()
 	  m_stack_walk_64(TEXT("dbghelp.dll"), "StackWalk64"),
 	  m_sym_initialize(TEXT("dbghelp.dll"), "SymInitialize"),
 	  m_sym_function_table_access_64(TEXT("dbghelp.dll"), "SymFunctionTableAccess64"),
-	  m_sym_get_module_base_64(TEXT("dbghelp.dll"), "SymGetModuleBase64")
+	  m_sym_get_module_base_64(TEXT("dbghelp.dll"), "SymGetModuleBase64"),
+	  m_rtl_capture_context(TEXT("kernel32.dll"), "RtlCaptureContext")
 {
 	// zap the structs
 	memset(&m_stackframe, 0, sizeof(m_stackframe));
@@ -797,6 +820,34 @@ stack_walker::stack_walker()
 //  reset - set up a new context
 //-------------------------------------------------
 
+bool stack_walker::reset()
+{
+	// set up the initial state
+	if (!m_rtl_capture_context)
+		return false;
+	(*m_rtl_capture_context)(&m_context);
+	m_thread = GetCurrentThread();
+	m_first = true;
+
+	// initialize the stackframe
+	memset(&m_stackframe, 0, sizeof(m_stackframe));
+	m_stackframe.AddrPC.Mode = AddrModeFlat;
+	m_stackframe.AddrFrame.Mode = AddrModeFlat;
+	m_stackframe.AddrStack.Mode = AddrModeFlat;
+
+	// pull architecture-specific fields from the context
+#ifdef PTR64
+	m_stackframe.AddrPC.Offset = m_context.Rip;
+	m_stackframe.AddrFrame.Offset = m_context.Rsp;
+	m_stackframe.AddrStack.Offset = m_context.Rsp;
+#else
+	m_stackframe.AddrPC.Offset = m_context.Eip;
+	m_stackframe.AddrFrame.Offset = m_context.Ebp;
+	m_stackframe.AddrStack.Offset = m_context.Esp;
+#endif
+	return true;
+}
+
 void stack_walker::reset(CONTEXT &initial, HANDLE thread)
 {
 	// set up the initial state

src/osd/windows/winmain.h

@@ -149,3 +149,4 @@ void CLIB_DECL mame_printf_verbose(const char *text, ...) ATTR_PRINTF(1,2);
 
 // use this to ping the watchdog
 void winmain_watchdog_ping(void);
+void winmain_dump_stack();

src/osd/windows/winmisc.c

@@ -50,6 +50,7 @@
 // MAMEOS headers
 #include "winutf8.h"
 #include "strconv.h"
+#include "strconv.h"
 
 
 //============================================================
@@ -67,6 +68,14 @@
 
 
 
+//============================================================
+//  GLOBAL VARIABLES
+//============================================================
+
+void (*s_debugger_stack_crawler)() = NULL;
+
+
+
 //============================================================
 //  osd_malloc
 //============================================================
@@ -167,4 +176,6 @@ void osd_break_into_debugger(const char *message)
 		win_output_debug_string_utf8(message);
 		DebugBreak();
 	}
+	else if (s_debugger_stack_crawler != NULL)
+		(*s_debugger_stack_crawler)();
 }