Scale the OSR optimization threshold by loop nesting depth.

runtime/vm/il_printer.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/il_printer.h"
 
 #include "vm/intermediate_language.h"
 #include "vm/os.h"
 #include "vm/parser.h"
 
@@ skipping 843 matching lines @@
   }
 }
 
 
 void ParameterInstr::PrintOperandsTo(BufferFormatter* f) const {
   f->Print("%"Pd, index());
 }
 
 
 void CheckStackOverflowInstr::PrintOperandsTo(BufferFormatter* f) const {
-  if (in_loop()) f->Print("loop");
+  if (in_loop()) f->Print("depth %"Pd, loop_depth());
 }
 
 
 void TargetEntryInstr::PrintTo(BufferFormatter* f) const {
   f->Print("B%"Pd"[target]:%"Pd, block_id(), GetDeoptId());
   if (HasParallelMove()) {
     f->Print(" ");
     parallel_move()->PrintTo(f);
   }
 }
@@ skipping 73 matching lines @@
       f->Print(" [");
       locations_[i].PrintTo(f);
       f->Print("]");
     }
   }
   f->Print(" }");
   if (outer_ != NULL) outer_->PrintTo(f);
 }
 
 }  // namespace dart