Merged r19834, r19843 into 3.24 branch.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index dfe98ec080c38009871c4f2357d532e5ec8d40d1..82cf45f74213e73d0acf28f96e832ad2839a53e8 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -590,6 +590,9 @@ void Heap::GarbageCollectionEpilogue() {
   if (FLAG_code_stats) ReportCodeStatistics("After GC");
 #endif
   if (FLAG_deopt_every_n_garbage_collections > 0) {
+    // TODO(jkummerow/ulan/jarin): This is not safe! We can't assume that
+    // the topmost optimized frame can be deoptimized safely, because it
+    // might not have a lazy bailout point right after its current PC.
     if (++gcs_since_last_deopt_ == FLAG_deopt_every_n_garbage_collections) {
       Deoptimizer::DeoptimizeAll(isolate());
       gcs_since_last_deopt_ = 0;