Merged r17432, r17526, r17545, r17620, r17747 into 3.21 branch.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 47634ec22b285d3ea0485ec9748ebe564b09220e..1aa3776bde9c535c95fad2a1f556a759d57875f3 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -262,8 +262,11 @@ static bool AlwaysFullCompiler(Isolate* isolate) {
 
 void OptimizingCompiler::RecordOptimizationStats() {
   Handle<JSFunction> function = info()->closure();
-  int opt_count = function->shared()->opt_count();
-  function->shared()->set_opt_count(opt_count + 1);
+  if (!function->IsOptimized()) {
+    // Concurrent recompilation and OSR may race.  Increment only once.
+    int opt_count = function->shared()->opt_count();
+    function->shared()->set_opt_count(opt_count + 1);
+  }
   double ms_creategraph = time_taken_to_create_graph_.InMillisecondsF();
   double ms_optimize = time_taken_to_optimize_.InMillisecondsF();
   double ms_codegen = time_taken_to_codegen_.InMillisecondsF();