[clangd] Record IO precentage for first preamble build of the instance

[adamcz]

Thanks, I was just about to fix that!

clang-tools-extra/clangd/TUScheduler.cpp

115

You're not using Label anywhere. Replace first_build below with Label.

[kadircet]

• Fix c/p error..

[kadircet]

clang-tools-extra/clangd/TUScheduler.cpp

115

oops, did that

clang-tools-extra/clangd/TUScheduler.cpp

PreambleBuildFilesystemLatency("preamble_fs_latency",
                                    trace::Metric::Distribution, "build_type");
 // Tracks latency of FS operations done during a preamble build as a ratio of
 // preamble build time. build_type is same as above.
 constexpr trace::Metric PreambleBuildFilesystemLatencyRatio(
     "preamble_fs_latency_ratio", trace::Metric::Distribution, "build_type");
 
 void reportPreambleBuild(const PreambleBuildStats &Stats,
                          bool IsFirstPreamble) {
-  static llvm::once_flag OnceFlag;
-  llvm::call_once(OnceFlag, [&] {
+  auto RecordWithLabel = [&Stats](llvm::StringRef Label) {
     PreambleBuildFilesystemLatency.record(Stats.FileSystemTime, "first_build");
-  });
-
-  const std::string Label =
-      IsFirstPreamble ? "first_build_for_file" : "rebuild";
-  PreambleBuildFilesystemLatency.record(Stats.FileSystemTime, Label);
     if (Stats.TotalBuildTime > 0) // Avoid division by zero.
       PreambleBuildFilesystemLatencyRatio.record(
-        Stats.FileSystemTime / Stats.TotalBuildTime, Label);
+          Stats.FileSystemTime / Stats.TotalBuildTime, "first_build");
+  };
+
+  static llvm::once_flag OnceFlag;
+  llvm::call_once(OnceFlag, [&] { RecordWithLabel("first_build"); });
+  RecordWithLabel(IsFirstPreamble ? "first_build_for_file" : "rebuild");
 }
 
 class ASTWorker;
 } // namespace
 
 static clang::clangd::Key<std::string> FileBeingProcessed;
 
 llvm::Optional<llvm::StringRef> TUScheduler::getFileBeingProcessedInContext() {