Build and use stack maps in the SSA compiler.

runtime/vm/locations.h

 // 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.
 
 #ifndef VM_LOCATIONS_H_
 #define VM_LOCATIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/bitfield.h"
@@ skipping 250 matching lines @@
   Location* out_slot() {
     return &output_location_;
   }
 
 
   void set_out(Location loc) {
     ASSERT(!is_call() || loc.IsRegister());
     output_location_ = loc;
   }
 
+  BitmapBuilder* stack_bitmap() const { return stack_bitmap_; }
+
   bool is_call() const {
     return is_call_;
   }
 
   void PrintTo(BufferFormatter* f) const;
 
   static LocationSummary* Make(intptr_t input_count,
                                Location out,
                                LocationSummary::ContainsCall contains_call);
 
  private:
   // TODO(vegorov): replace with ZoneArray.
   GrowableArray<Location> input_locations_;
   GrowableArray<Location> temp_locations_;
   Location output_location_;
-
+  BitmapBuilder* stack_bitmap_;
   const bool is_call_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_LOCATIONS_H_