Fix minor clang warnings for tflite, for toolchains with pickier configurations.

Warnings addressed:
-Wsign-conversion
-Wcovered-switch-default
-Wformat-nonliteral

PiperOrigin-RevId: 241808610

tensorflow/lite/minimal_logging.cc

@@ -35,9 +35,8 @@ const char* MinimalLogger::GetSeverityName(LogSeverity severity) {
       return "WARNING";
     case TFLITE_LOG_ERROR:
       return "ERROR";
-    default:
-      return "<Unknown severity>";
   }
+  return "<Unknown severity>";
 }
 
 }  // namespace logging_internal

tensorflow/lite/minimal_logging_default.cc

@@ -23,7 +23,10 @@ namespace logging_internal {
 void MinimalLogger::LogFormatted(LogSeverity severity, const char* format,
                                  va_list args) {
   fprintf(stderr, "%s: ", GetSeverityName(severity));
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
   vfprintf(stderr, format, args);
+#pragma clang diagnostic pop
   fputc('\n', stderr);
 }
 

tensorflow/lite/profiling/time.cc

@@ -29,9 +29,10 @@ namespace time {
 #if defined(_MSC_VER)
 
 uint64_t NowMicros() {
-  return std::chrono::duration_cast<std::chrono::microseconds>(
-             std::chrono::system_clock::now().time_since_epoch())
-      .count();
+  return static_cast<uint64_t>(
+      std::chrono::duration_cast<std::chrono::microseconds>(
+          std::chrono::system_clock::now().time_since_epoch())
+          .count());
 }
 
 void SleepForMicros(uint64_t micros) {

tensorflow/lite/util.cc

@@ -24,7 +24,8 @@ bool IsFlexOp(const char* custom_name) {
 }
 
 TfLiteIntArray* ConvertVectorToTfLiteIntArray(const std::vector<int>& input) {
-  return ConvertArrayToTfLiteIntArray(input.size(), input.data());
+  return ConvertArrayToTfLiteIntArray(static_cast<int>(input.size()),
+                                      input.data());
 }
 
 TfLiteIntArray* ConvertArrayToTfLiteIntArray(const int rank, const int* dims) {