[libc][windows] remove SEH

Author: SchrodingerZhu

libc/src/__support/time/windows/clock_gettime.cpp

@@ -37,52 +37,48 @@ static long long get_ticks_per_second() {
 ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
   using namespace time_units;
   ErrorOr<int> ret = 0;
-  __try {
-    switch (clockid) {
-    default:
-      ret = cpp::unexpected(EINVAL);
-      break;
+  switch (clockid) {
+  default:
+    ret = cpp::unexpected(EINVAL);
+    break;
 
-    case CLOCK_MONOTONIC: {
-      // see
-      // https://learn.microsoft.com/en-us/windows/win32/sysinfo/acquiring-high-resolution-time-stamps
-      // Is the performance counter monotonic (non-decreasing)?
-      // Yes. QPC does not go backward.
-      UNINITIALIZED LARGE_INTEGER buffer;
-      // On systems that run Windows XP or later, the function will always
-      // succeed and will thus never return zero.
-      ::QueryPerformanceCounter(&buffer);
-      long long freq = get_ticks_per_second();
-      long long ticks = buffer.QuadPart;
-      long long tv_sec = ticks / freq;
-      long long tv_nsec = (ticks % freq) * 1_s_ns / freq;
-      ts->tv_sec = static_cast<decltype(ts->tv_sec)>(tv_sec);
-      ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(tv_nsec);
-      break;
-    }
-    case CLOCK_REALTIME: {
-      // https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime
-      // GetSystemTimePreciseAsFileTime
-      // This function is best suited for high-resolution time-of-day
-      // measurements, or time stamps that are synchronized to UTC
-      UNINITIALIZED FILETIME file_time;
-      UNINITIALIZED ULARGE_INTEGER time;
-      ::GetSystemTimePreciseAsFileTime(&file_time);
-      time.LowPart = file_time.dwLowDateTime;
-      time.HighPart = file_time.dwHighDateTime;
+  case CLOCK_MONOTONIC: {
+    // see
+    // https://learn.microsoft.com/en-us/windows/win32/sysinfo/acquiring-high-resolution-time-stamps
+    // Is the performance counter monotonic (non-decreasing)?
+    // Yes. QPC does not go backward.
+    UNINITIALIZED LARGE_INTEGER buffer;
+    // On systems that run Windows XP or later, the function will always
+    // succeed and will thus never return zero.
+    ::QueryPerformanceCounter(&buffer);
+    long long freq = get_ticks_per_second();
+    long long ticks = buffer.QuadPart;
+    long long tv_sec = ticks / freq;
+    long long tv_nsec = (ticks % freq) * 1_s_ns / freq;
+    ts->tv_sec = static_cast<decltype(ts->tv_sec)>(tv_sec);
+    ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(tv_nsec);
+    break;
+  }
+  case CLOCK_REALTIME: {
+    // https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime
+    // GetSystemTimePreciseAsFileTime
+    // This function is best suited for high-resolution time-of-day
+    // measurements, or time stamps that are synchronized to UTC
+    UNINITIALIZED FILETIME file_time;
+    UNINITIALIZED ULARGE_INTEGER time;
+    ::GetSystemTimePreciseAsFileTime(&file_time);
+    time.LowPart = file_time.dwLowDateTime;
+    time.HighPart = file_time.dwHighDateTime;
 
-      // adjust to POSIX epoch (from Jan 1, 1601 to Jan 1, 1970)
-      constexpr unsigned long long HNS_PER_SEC = 1_s_ns / 100ULL;
-      time.QuadPart -= (11644473600ULL * HNS_PER_SEC);
-      unsigned long long tv_sec = time.QuadPart / HNS_PER_SEC;
-      unsigned long long tv_nsec = (time.QuadPart % HNS_PER_SEC) * 100ULL;
-      ts->tv_sec = static_cast<decltype(ts->tv_sec)>(tv_sec);
-      ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(tv_nsec);
-      break;
-    }
-    }
-  } __except (EXCEPTION_EXECUTE_HANDLER) {
-    ret = cpp::unexpected(EFAULT);
+    // adjust to POSIX epoch (from Jan 1, 1601 to Jan 1, 1970)
+    constexpr unsigned long long HNS_PER_SEC = 1_s_ns / 100ULL;
+    time.QuadPart -= (11644473600ULL * HNS_PER_SEC);
+    unsigned long long tv_sec = time.QuadPart / HNS_PER_SEC;
+    unsigned long long tv_nsec = (time.QuadPart % HNS_PER_SEC) * 100ULL;
+    ts->tv_sec = static_cast<decltype(ts->tv_sec)>(tv_sec);
+    ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(tv_nsec);
+    break;
+  }
   }
   return ret;
 }