[runtime stats] Fix crash when RCS are enabled dynamically.

src/counters.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/counters.h"
 
 #include <iomanip>
 
 #include "src/base/platform/platform.h"
 #include "src/isolate.h"
@@ skipping 291 matching lines @@
     // accurate, just avoid crashing by keeping the chain intact.
     RuntimeCallTimer* next = stats->current_timer_.Value();
     while (next->parent() != timer) next = next->parent();
     next->parent_.SetValue(timer->Stop());
   }
 }
 
 // static
 void RuntimeCallStats::CorrectCurrentCounterId(RuntimeCallStats* stats,
                                                CounterId counter_id) {
-  DCHECK_NOT_NULL(stats->current_timer_.Value());
-  RuntimeCallCounter* counter = &(stats->*counter_id);
-  stats->current_timer_.Value()->counter_ = counter;
+  RuntimeCallTimer* timer = stats->current_timer_.Value();
+  // When RCS are enabled dynamically there might be no current timer set up.
+  if (timer == nullptr) return;
+  timer->counter_ = &(stats->*counter_id);
 }
 
 void RuntimeCallStats::Print(std::ostream& os) {
   RuntimeCallStatEntries entries;
   if (current_timer_.Value() != nullptr) {
     current_timer_.Value()->Elapsed();
   }
 
 #define PRINT_COUNTER(name) entries.Add(&this->name);
   FOR_EACH_MANUAL_COUNTER(PRINT_COUNTER)
@@ skipping 71 matching lines @@
 #define DUMP_COUNTER(name) \
   if (this->Handler_##name.count > 0) this->Handler_##name.Dump(value);
   FOR_EACH_HANDLER_COUNTER(DUMP_COUNTER)
 #undef DUMP_COUNTER
 
   in_use_ = false;
 }
 
 }  // namespace internal
 }  // namespace v8