In verbose mode, log Error Prone performance details

check_api/src/main/java/com/google/errorprone/BaseErrorProneJavaCompiler.java

@@ -101,6 +101,11 @@ static void addTaskListener(
     if (refactoringCollection[0] != null) {
       javacTask.addTaskListener(new RefactoringTask(context, refactoringCollection[0]));
     }
+
+    if (Options.instance(context).isSet("-verbose")) {
+      javacTask.addTaskListener(
+          new TimingReporter(ErrorProneTimings.instance(context), Log.instance(context)));
+    }
   }
 
   @Override

check_api/src/main/java/com/google/errorprone/TimingReporter.java

@@ -0,0 +1,43 @@
+package com.google.errorprone;
+
+import static java.util.stream.Collectors.joining;
+
+import com.sun.source.util.TaskEvent;
+import com.sun.source.util.TaskEvent.Kind;
+import com.sun.source.util.TaskListener;
+import com.sun.tools.javac.util.Log;
+import java.time.Duration;
+import java.util.Map;
+
+final class TimingReporter implements TaskListener {
+  private final ErrorProneTimings errorProneTimings;
+  private final Log log;
+
+  TimingReporter(ErrorProneTimings errorProneTimings, Log log) {
+    this.errorProneTimings = errorProneTimings;
+    this.log = log;
+  }
+
+  @Override
+  public void finished(TaskEvent event) {
+    if (event.getKind() != Kind.COMPILATION) {
+      return;
+    }
+
+    Map<String, Duration> timings = errorProneTimings.timings();
+    if (timings.isEmpty()) {
+      return;
+    }
+
+    Duration totalTime = timings.values().stream().reduce(Duration.ZERO, Duration::plus);
+    String slowestChecks =
+        timings.entrySet().stream()
+            .sorted(Map.Entry.<String, Duration>comparingByValue().reversed())
+            .limit(10)
+            .map(e -> e.getValue() + ": " + e.getKey())
+            .collect(joining("\n   ", "   ", ""));
+
+    log.printVerbose(
+        "error.prone.timing", totalTime, errorProneTimings.initializationTime(), slowestChecks);
+  }
+}

check_api/src/main/java/com/google/errorprone/errors.properties

@@ -20,3 +20,5 @@ compiler.err.error.prone={0}
 compiler.err.error.prone.crash=An unhandled exception was thrown by the Error Prone static analysis plugin.\n   Please report this at https://github.com/google/error-prone/issues/new and include the following:\n\n   error-prone version: {1}\n   BugPattern: {2}\n   Stack Trace:\n   {0}
 compiler.warn.error.prone={0}
 compiler.note.error.prone={0}
+compiler.misc.verbose.error.prone.compiles.with.fix=Running `compilesWithFix` for {0} in {1}
+compiler.misc.verbose.error.prone.timing=Error Prone analysis took {0} (plus {1} for initialization); slowest checks:\n{2}

check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java

@@ -103,6 +103,7 @@
 import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
 import com.sun.tools.javac.util.Context;
 import com.sun.tools.javac.util.JCDiagnostic;
+import com.sun.tools.javac.util.Log;
 import com.sun.tools.javac.util.Options;
 import com.sun.tools.javac.util.Position;
 import java.io.IOException;
@@ -1298,6 +1299,15 @@ private static boolean compilesWithFix(
       return false;
     }
 
+    if (Options.instance(state.context).isSet("-verbose")) {
+      JCCompilationUnit compilationUnit = (JCCompilationUnit) state.getPath().getCompilationUnit();
+      Log.instance(state.context)
+          .printVerbose(
+              "error.prone.compiles.with.fix",
+              fix.toString(compilationUnit),
+              compilationUnit.sourcefile);
+    }
+
     Result compilationResult = fixCompiler.compile(extraOptions);
     URI modifiedFileUri = FixCompiler.getModifiedFileUri(state);