Merged r19834, r19843 into 3.23 branch.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 1e9091b30d8bf00cc3907a51b9f5cb0e269f5fa6..d9dc8c19b07b11dae0d76bf6fe32fcab94be3ff1 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -561,6 +561,9 @@ 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;