Add --x-perf-report flag to the dartanalyzer command

pkg/analyzer_cli/lib/src/analyzer_impl.dart

Index: pkg/analyzer_cli/lib/src/analyzer_impl.dart
diff --git a/pkg/analyzer_cli/lib/src/analyzer_impl.dart b/pkg/analyzer_cli/lib/src/analyzer_impl.dart
index 84b28c50bd123501b512cfd3659fd0727fc6b4df..6a2e255e9ebf2e742dafaf67bb7d5bff9f2f5d59 100644
--- a/pkg/analyzer_cli/lib/src/analyzer_impl.dart
+++ b/pkg/analyzer_cli/lib/src/analyzer_impl.dart
@@ -121,13 +121,17 @@ class AnalyzerImpl {
 
   /// Fills [errorInfos] using [sources].
   void prepareErrors() {
-    for (Source source in sources) {
-      context.computeErrors(source);
-
-      errorInfos.add(context.getErrors(source));
-    }
+    return _prepareErrorsTag.makeCurrentWhile(() {
+      for (Source source in sources) {
+        context.computeErrors(source);
+        errorInfos.add(context.getErrors(source));

[Brian Wilkerson, 2015/12/16 15:08:43]

The original code looks weird to me. Seems like we should just have one line:

errorInfos.add(context.computeErrors(source));

[skybrian, 2015/12/17 04:20:27]

Yes that does seem strange, but I think I'd like to defer the fix to another
patch.

[Brian Wilkerson, 2015/12/17 15:05:41]

sounds good

+      }
+    });
   }
 
+  static final PerformanceTag _prepareErrorsTag =

[Brian Wilkerson, 2015/12/16 15:08:43]

Don't forget to sort and format the file before committing it.

[skybrian, 2015/12/17 04:20:27]

Formatted. It's not clear to me which order this file is sorted. What do you use
for this?

[Brian Wilkerson, 2015/12/17 15:05:41]

The sort function available from either IntelliJ or Atom.

+      new PerformanceTag("AnalyzerImpl.prepareErrors");
+
   /// Fills [sources].
   void prepareSources(LibraryElement library) {
     var units = new Set<CompilationUnitElement>();
@@ -154,15 +158,13 @@ class AnalyzerImpl {
           "${librarySource.fullName} is a part and can not be analyzed.");
       return ErrorSeverity.ERROR;
     }
-    // Resolve library.
-    var libraryElement = context.computeLibraryElement(librarySource);
-    // Prepare source and errors.
+    var libraryElement = _resolveLibrary();
     prepareSources(libraryElement);
     prepareErrors();
 
     // Print errors and performance numbers.
     if (printMode == 1) {
-      _printErrorsAndPerf();
+      _printErrors();
     } else if (printMode == 2) {
       _printColdPerf();
     }
@@ -175,6 +177,15 @@ class AnalyzerImpl {
     return status;
   }
 
+  LibraryElement _resolveLibrary() {
+    return _resolveLibraryTag.makeCurrentWhile(() {
+      return context.computeLibraryElement(librarySource);
+    });
+  }
+
+  static final PerformanceTag _resolveLibraryTag =
+      new PerformanceTag("AnalyzerImpl._resolveLibrary");
+
   bool _isDesiredError(AnalysisError error) {
     if (error.errorCode.type == ErrorType.TODO) {
       return false;
@@ -215,7 +226,7 @@ class AnalyzerImpl {
     outSink.writeln("total-cold:$totalTime");
   }
 
-  _printErrorsAndPerf() {
+  _printErrors() {
     // The following is a hack. We currently print out to stderr to ensure that
     // when in batch mode we print to stderr, this is because the prints from
     // batch are made to stderr. The reason that options.shouldBatch isn't used