Swift: fix diagnostic source creation being called really once

Author: redsun82

swift/extractor/main.cpp

@@ -220,7 +220,6 @@ int main(int argc, char** argv, char** envp) {
     codeql::Logger logger{"main"};
     LOG_INFO("calling extractor with arguments \"{}\"", argDump(argc, argv));
     LOG_DEBUG("environment:\n{}\n", envDump(envp));
-    DIAGNOSE_ERROR(internal_error, "prout {}", 42);
   }
 
   auto openInterception = codeql::setupFileInterception(configuration);

swift/log/SwiftDiagnostics.h

@@ -83,4 +83,11 @@ inline void internal_error() {
 }
 }  // namespace diagnostics
 
+namespace detail {
+template <void (*Func)()>
+inline void createSwiftDiagnosticsSourceOnce() {
+  static int ignore = (Func(), 0);
+  std::ignore = ignore;
+}
+}  // namespace detail
 }  // namespace codeql

swift/log/SwiftLogging.h

@@ -50,11 +50,10 @@
 #define DIAGNOSE_CRITICAL(ID, ...) DIAGNOSE_WITH_LEVEL(critical, ID, __VA_ARGS__)
 #define DIAGNOSE_ERROR(ID, ...) DIAGNOSE_WITH_LEVEL(error, ID, __VA_ARGS__)
 
-#define DIAGNOSE_WITH_LEVEL(LEVEL, ID, ...)              \
-  do {                                                   \
-    static int _ignore = (codeql::diagnostics::ID(), 0); \
-    std::ignore = _ignore;                               \
-    LOG_WITH_LEVEL_AND_CATEGORY(LEVEL, ID, __VA_ARGS__); \
+#define DIAGNOSE_WITH_LEVEL(LEVEL, ID, ...)                                      \
+  do {                                                                           \
+    codeql::detail::createSwiftDiagnosticsSourceOnce<codeql::diagnostics::ID>(); \
+    LOG_WITH_LEVEL_AND_CATEGORY(LEVEL, ID, __VA_ARGS__);                         \
   } while (false)
 
 // avoid calling into binlog's original macros