Fix CompilerStats aggregation: do not aggregate if there is no mutator thread (isolate shutting dow…

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 1670 matching lines @@
         ASSERT(thread->compiler_stats()->IsCleared());
         const Error& error = Error::Handle(zone,
             Compiler::CompileOptimizedFunction(thread,
                                                function,
                                                Compiler::kNoOSRDeoptId));
         // TODO(srdjan): We do not expect errors while compiling optimized
         // code, any errors should have been caught when compiling
         // unoptimized code. Any issues while optimizing are flagged by
         // making the result invalid.
         ASSERT(error.IsNull());
-        isolate->aggregate_compiler_stats()->Add(*thread->compiler_stats());
+        // We cannot aggregate stats if isolate is shutting down.
+        if (isolate->HasMutatorThread()) {
+          isolate->aggregate_compiler_stats()->Add(*thread->compiler_stats());
+        }
         thread->compiler_stats()->Clear();
         QueueElement* qelem = function_queue()->Remove();
         delete qelem;
         function = function_queue()->PeekFunction();
       }
     }
     Thread::ExitIsolateAsHelper();
     {
       // Wait to be notified when the work queue is not empty.
       MonitorLocker ml(queue_monitor_);
@@ skipping 200 matching lines @@
 }
 
 
 void BackgroundCompiler::EnsureInit(Thread* thread) {
   UNREACHABLE();
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart