Fix #8860: [Win32] Crashlog window wasn't reliably shown for crashes not on the main thread.

src/crashlog.h

@@ -114,6 +114,12 @@ public:
 	 */
 	static void InitialiseCrashLog();
 
+	/**
+	 * Prepare crash log handler for a newly started thread.
+	 * @note must be implemented by all implementers of CrashLog.
+	 */
+	static void InitThread();
+
 	static void SetErrorMessage(const char *message);
 	static void AfterCrashLogCleanup();
 };

src/os/macosx/crashlog_osx.cpp

@@ -257,3 +257,7 @@ void CDECL HandleCrash(int signum)
 		signal(*i, HandleCrash);
 	}
 }
+
+/* static */ void CrashLog::InitThread()
+{
+}

src/os/unix/crashlog_unix.cpp

@@ -181,3 +181,7 @@ static void CDECL HandleCrash(int signum)
 		signal(*i, HandleCrash);
 	}
 }
+
+/* static */ void CrashLog::InitThread()
+{
+}

src/os/windows/crashlog_win.cpp

@@ -537,7 +537,7 @@ static void ShowCrashlogWindow();
  * Stack pointer for use when 'starting' the crash handler.
  * Not static as gcc's inline assembly needs it that way.
  */
-void *_safe_esp = nullptr;
+thread_local void *_safe_esp = nullptr;
 
 static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 {
@@ -604,6 +604,19 @@ static void CDECL CustomAbort(int signal)
 }
 
 /* static */ void CrashLog::InitialiseCrashLog()
+{
+	CrashLog::InitThread();
+
+	/* SIGABRT is not an unhandled exception, so we need to intercept it. */
+	signal(SIGABRT, CustomAbort);
+#if defined(_MSC_VER)
+	/* Don't show abort message as we will get the crashlog window anyway. */
+	_set_abort_behavior(0, _WRITE_ABORT_MSG);
+#endif
+	SetUnhandledExceptionFilter(ExceptionHandler);
+}
+
+/* static */ void CrashLog::InitThread()
 {
 #if defined(_M_AMD64) || defined(_M_ARM64)
 	CONTEXT ctx;
@@ -613,28 +626,22 @@ static void CDECL CustomAbort(int signal)
 	 * function. As we are simulating a function call with the safe ESP value,
 	 * we need to subtract 8 for the imaginary return address otherwise stack
 	 * alignment would be wrong in the called function. */
-#if defined(_M_ARM64)
+#	if defined(_M_ARM64)
 	_safe_esp = (void *)(ctx.Sp - 8);
-#else
+#	else
 	_safe_esp = (void *)(ctx.Rsp - 8);
-#endif
+#	endif
 #else
-#if defined(_MSC_VER)
+	void *safe_esp;
+#	if defined(_MSC_VER)
 	_asm {
-		mov _safe_esp, esp
+		mov safe_esp, esp
 	}
-#else
-	asm("movl %esp, __safe_esp");
-#endif
-#endif
-
-	/* SIGABRT is not an unhandled exception, so we need to intercept it. */
-	signal(SIGABRT, CustomAbort);
-#if defined(_MSC_VER)
-	/* Don't show abort message as we will get the crashlog window anyway. */
-	_set_abort_behavior(0, _WRITE_ABORT_MSG);
+#	else
+	asm("movl %esp, _safe_esp");
+#	endif
+	_safe_esp = safe_esp;
 #endif
-	SetUnhandledExceptionFilter(ExceptionHandler);
 }
 
 /* The crash log GUI */

src/thread.h

@@ -11,6 +11,7 @@
 #define THREAD_H
 
 #include "debug.h"
+#include "crashlog.h"
 #include <system_error>
 #include <thread>
 
@@ -47,6 +48,7 @@ inline bool StartNewThread(std::thread *thr, const char *name, TFn&& _Fx, TArgs&
 	try {
 		std::thread t([] (const char *name, TFn&& F, TArgs&&... A) {
 				SetCurrentThreadName(name);
+				CrashLog::InitThread();
 				try {
 					/* Call user function with the given arguments. */
 					F(A...);