Build and use stack maps in the SSA compiler.

runtime/vm/locations.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/locations.h"
 
 #include "vm/il_printer.h"
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph_compiler.h"
 
 namespace dart {
 
 LocationSummary::LocationSummary(intptr_t input_count,
                                  intptr_t temp_count,
                                  LocationSummary::ContainsCall contains_call)
     : input_locations_(input_count),
       temp_locations_(temp_count),
       output_location_(),
-      is_call_(contains_call == LocationSummary::kCall) {
+      stack_bitmap_(NULL),
+      is_call_(contains_call == kCall) {
+  if (is_call()) stack_bitmap_ = new BitmapBuilder();
   for (intptr_t i = 0; i < input_count; i++) {
     input_locations_.Add(Location());
   }
   for (intptr_t i = 0; i < temp_count; i++) {
     temp_locations_.Add(Location());
   }
 }
 
 
 LocationSummary* LocationSummary::Make(
@@ skipping 73 matching lines @@
 
   if (!out().IsInvalid()) {
     f->Print(" => ");
     out().PrintTo(f);
   }
 
   if (is_call()) f->Print(" C");
 }
 
 }  // namespace dart