Fine. Return from LibraryContext without logging if the cycle is already loaded.

It writes too much, and with fine grained dependencies this is especially
prominent, we don't do analysis for most of files afterwards.

Change-Id: Idccef82f3b46980b6942c403871f588e21e128c1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/408680
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/library_context.dart

@@ -196,15 +196,20 @@ class LibraryContext {
       }
     }
 
+    var libraryCycle = performance.run('libraryCycle', (performance) {
+      fileSystemState.newFileOperationPerformance = performance;
+      try {
+        return targetLibrary.libraryCycle;
+      } finally {
+        fileSystemState.newFileOperationPerformance = null;
+      }
+    });
+
+    if (loadedBundles.contains(libraryCycle)) {
+      return;
+    }
+
     logger.run('Prepare linked bundles', () {
-      var libraryCycle = performance.run('libraryCycle', (performance) {
-        fileSystemState.newFileOperationPerformance = performance;
-        try {
-          return targetLibrary.libraryCycle;
-        } finally {
-          fileSystemState.newFileOperationPerformance = null;
-        }
-      });
       loadBundle(libraryCycle);
       logger.writeln(
         '[librariesTotal: $librariesTotal]'