Support OSR in for-in loops.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8572 matching lines @@
 #if defined(USE_SIMULATOR)
   return isolate->heap()->true_value();
 #else
   return isolate->heap()->false_value();
 #endif
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_OptimizeFunctionOnNextCall) {
   HandleScope scope(isolate);
-  ASSERT(args.length() == 1);
+  ASSERT(args.length() == 1 || args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
+
   if (!function->IsOptimizable()) return isolate->heap()->undefined_value();
   function->MarkForLazyRecompilation();
+
+  Code* unoptimized = function->shared()->code();
+  if (args.length() == 2 &&
+      unoptimized->kind() == Code::FUNCTION) {
+    CONVERT_ARG_HANDLE_CHECKED(String, type, 1);
+    CHECK(type->IsEqualTo(CStrVector("osr")));
+    isolate->runtime_profiler()->AttemptOnStackReplacement(*function);
+    unoptimized->set_allow_osr_at_loop_nesting_level(
+        Code::kMaxLoopNestingMarker);
+  }
+
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOptimizationStatus) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   // The least significant bit (after untagging) indicates whether the
   // function is currently optimized, regardless of reason.
   if (!V8::UseCrankshaft()) {
@@ skipping 5070 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal