Add a perf test for generating linked summaries.

pkg/front_end/tool/perf.dart

Index: pkg/front_end/tool/perf.dart
diff --git a/pkg/front_end/tool/perf.dart b/pkg/front_end/tool/perf.dart
index 4fa76ed5867abd8f575e1de9e67f7f5ebf9d64d4..be4f3d1f7fc035e1829a62872188ebb56bd78793 100644
--- a/pkg/front_end/tool/perf.dart
+++ b/pkg/front_end/tool/perf.dart
@@ -21,6 +21,7 @@ import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
+import 'package:analyzer/src/summary/link.dart';
 import 'package:analyzer/src/summary/prelink.dart';
 import 'package:analyzer/src/summary/summarize_ast.dart';
 import 'package:kernel/analyzer/loader.dart';
@@ -88,6 +89,11 @@ main(List<String> args) async {
       Set<Source> files = scanReachableFiles(entryUri);
       // TODO(sigmund): replace the warmup with instrumented snapshots.
       for (int i = 0; i < 10; i++) prelinkedSummarizeFiles(files);
+    },
+    'linked_summarize': () async {
+      Set<Source> files = scanReachableFiles(entryUri);
+      // TODO(sigmund): replace the warmup with instrumented snapshots.
+      for (int i = 0; i < 10; i++) linkedSummarizeFiles(files);
     }
   };
 
@@ -262,6 +268,61 @@ void prelinkedSummarizeFiles(Set<Source> files) {
   report('prelink', prelinkTimer.elapsedMicroseconds);
 }
 
+/// Produces linked summaries for every file in [files] and reports the time
+/// spent doing so.
+void linkedSummarizeFiles(Set<Source> files) {
+  // The code below will record again how many chars are scanned and how long it
+  // takes to scan them, even though we already did so in [scanReachableFiles].
+  // Recording and reporting this twice is unnecessary, but we do so for now to
+  // validate that the results are consistent.
+  scanTimer = new Stopwatch();
+  var old = scanTotalChars;
+  scanTotalChars = 0;
+  parseTimer = new Stopwatch();
+  unlinkedSummarizeTimer = new Stopwatch();
+  var unlinkedSummaries = <String, UnlinkedUnit>{};
+  for (var source in files) {
+    unlinkedSummaries[source.uri.toString()] = unlinkedSummarize(source);
+  }
+  var prelinkTimer = new Stopwatch()..start();
+  Set<String> libraryUris =
+      files.map((source) => source.uri.toString()).toSet();
+  UnlinkedUnit getUnit(String uri) {
+    var result = unlinkedSummaries[uri];
+    if (result == null) {
+      print('Warning: no summary found for: $uri');
+    }
+    return result;
+  }
+
+  String getDeclaredVariable(String s) => null;
+  var prelinkedLibraries =
+      setupForLink(libraryUris, getUnit, getDeclaredVariable);

[Siggi Cherem (dart-lang), 2016/12/07 23:21:29]

is there a difference between prelink and setupForLink?

If not, could we refactor the logic in prelinkedSummarizeFilzes so we can reuse
some code and only do the additional link step here?

[Paul Berry, 2016/12/07 23:54:40]

Good point.  PTAL.

+  prelinkTimer.stop();
+  var linkTimer = new Stopwatch()..start();
+  LinkedLibrary getDependency(String uri) {
+    // getDependency should never be called because all dependencies are present
+    // in [prelinkedLibraries].
+    print('Warning: getDependency called for: $uri');
+    return null;
+  }
+
+  bool strong = true;
+  relink(prelinkedLibraries, getDependency, getUnit, strong);
+  linkTimer.stop();
+
+  if (old != scanTotalChars) print('input size changed? ${old} chars');
+  report("scan", scanTimer.elapsedMicroseconds);
+  report("parse", parseTimer.elapsedMicroseconds);
+  report('unlinked summarize', unlinkedSummarizeTimer.elapsedMicroseconds);
+  report(
+      'unlinked summarize + parse',
+      unlinkedSummarizeTimer.elapsedMicroseconds +
+          parseTimer.elapsedMicroseconds);
+  report('prelink', prelinkTimer.elapsedMicroseconds);
+  report('link', linkTimer.elapsedMicroseconds);
+}
+
 /// Add to [files] all sources reachable from [start].
 void collectSources(Source start, Set<Source> files) {
   if (!files.add(start)) return;