[heap] Minor MC: Add marking

src/heap/gc-tracer.cc

Index: src/heap/gc-tracer.cc
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index f7c67ace2b65f48f920f2fee6eddcf5bd3b58300..dd31fd715d2738bfc2ebd310bafb40ca333c89c6 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -503,15 +503,25 @@ void GCTracer::PrintNVP() const {
           heap_->semi_space_copied_rate_,
           NewSpaceAllocationThroughputInBytesPerMillisecond(),
           ContextDisposalRateInMilliseconds());
+#ifdef VERIFY_HEAP
+      // Fall through to allow printing minor MC numbers in case of verifying.
+      if (!FLAG_verify_minor_mc_marking) break;
+#else
       break;
+#endif  // VERIFY_HEAP
     case Event::MINOR_MARK_COMPACTOR:
       heap_->isolate()->PrintWithTimestamp(
           "pause=%.1f "
           "mutator=%.1f "
           "gc=%s "
-          "reduce_memory=%d\n",
-          duration, spent_in_mutator, current_.TypeName(true),
-          current_.reduce_memory);
+          "reduce_memory=%d "
+          "mark=%.2f "
+          "mark.roots=%.2f "
+          "mark.old_to_new=%.2f\n",
+          duration, spent_in_mutator, "mmc", current_.reduce_memory,
+          current_.scopes[Scope::MINOR_MC_MARK],
+          current_.scopes[Scope::MINOR_MC_MARK_ROOTS],
+          current_.scopes[Scope::MINOR_MC_MARK_OLD_TO_NEW_POINTERS]);
       break;
     case Event::MARK_COMPACTOR:
     case Event::INCREMENTAL_MARK_COMPACTOR: