fix(libc): end the process without detach routines in _Exit on Windows

On Windows std::_Exit ends in ExitProcess, which still runs every module's
DLL_PROCESS_DETACH and TLS callbacks after the other threads are gone. A
static destructor that joins a worker then waits forever: a title that calls
_Exit while libSceVideoOut's flip queue runs (ps5-opengl's retirement
fail-stop) stays alive in FlipQueue's destructor. _Exit and libkernel's _exit
now terminate the process with TerminateProcess, as _exit ends a POSIX
process: no atexit handlers, stream flushes or module destructors.

core/libs/prx/libc/include/Shutdown.hpp

@@ -12,5 +12,6 @@ extern "C" void LibcRequestShutdown_nid_postfix();
 extern "C" void LibcRequestExit_nid_postfix(int code);
 extern "C" [[noreturn]] void LibcAwaitExit_nid_postfix();
 extern "C" [[noreturn]] void LibcExit_nid_no_patch(int code);
+extern "C" [[noreturn]] void LibcTerminate_nid_no_patch(int code);
 
 #endif

core/libs/prx/libc/src/Process.cpp

@@ -8,6 +8,9 @@
 #include <mutex>
 #include <thread>
 #include <vector>
+#ifdef _WIN32
+#include <windows.h>
+#endif
 #include <atomic>
 #include <stdexcept>
 #include "prx/libc/include/Shutdown.hpp"
@@ -106,6 +109,13 @@ extern "C" {
         std::fprintf(stderr, "[libc] _Exit(%d) called from %p\n", code, __builtin_return_address(0));
         std::fflush(stderr);
     }
+    LibcTerminate_nid_no_patch(code);
+}
+
+[[noreturn]] void LibcTerminate_nid_no_patch(int code) {
+#ifdef _WIN32
+    TerminateProcess(GetCurrentProcess(), static_cast<UINT>(code));
+#endif
     std::_Exit(code);
 }
 

core/libs/prx/libkernel/System/src/Process.cpp

@@ -208,7 +208,7 @@ void APS5_VABI exit_nid_postfix(int code) {
 }
 
 [[noreturn]] void APS5_VABI _exit_nid_postfix(int status) {
-    std::_Exit(status);
+    LibcTerminate_nid_no_patch(status);
 }
 
 int APS5_VABI system_nid_postfix(const char* command) {

core/libs/tests/GuestSystemExit.cpp

@@ -5,6 +5,9 @@
 #include <cstdlib>
 #include <stdexcept>
 #include <cstring>
+#ifdef _WIN32
+#include <windows.h>
+#endif
 extern "C" int APS5_VABI sceSystemServiceLoadExec(const char*, const char* const*);
 extern "C" void APS5_VABI _Exit_nid_postfix(int);
 extern "C" void APS5_VABI catchReturnFromMain_nid_postfix(int);
@@ -27,11 +30,18 @@ void APS5_VABI QuickFirst() {
 }
 void Require(bool value) { if (!value) std::abort(); }
 void UnexpectedCleanup() { std::_Exit(3); }
+#ifdef _WIN32
+void WINAPI UnexpectedDetach(PVOID) { TerminateProcess(GetCurrentProcess(), 4); }
+#endif
 }
 int main(int argc, char** argv) {
     if (argc > 1 && std::strcmp(argv[1], "--immediate") == 0) {
         LibcRegisterShutdown_nid_postfix(UnexpectedCleanup);
         Require(std::atexit(UnexpectedCleanup) == 0);
+#ifdef _WIN32
+        auto slot = FlsAlloc(UnexpectedDetach);
+        Require(slot != FLS_OUT_OF_INDEXES && FlsSetValue(slot, &slot));
+#endif
         _Exit_nid_postfix(0);
         return 2;
     }