Record a correct deoptimization environment for slow-path code.

runtime/vm/locations.cc

 // Copyright (c) 2013, 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/assembler.h"
 #include "vm/il_printer.h"
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/stack_frame.h"
 
 namespace dart {
 
+intptr_t RegisterSet::RegisterCount(intptr_t registers) {
+  // Brian Kernighan's algorithm for counting the bits set.
+  intptr_t count = 0;
+  while (registers != 0) {
+    ++count;
+    registers &= (registers - 1);  // Clear the least significant bit set.
+  }
+  return count;
+}
+
+
 LocationSummary::LocationSummary(intptr_t input_count,
                                  intptr_t temp_count,
                                  LocationSummary::ContainsCall contains_call)
     : input_locations_(input_count),
       temp_locations_(temp_count),
       output_location_(),
       stack_bitmap_(NULL),
       contains_call_(contains_call),
       live_registers_() {
   for (intptr_t i = 0; i < input_count; i++) {
@@ skipping 159 matching lines @@
 
   if (!out().IsInvalid()) {
     f->Print(" => ");
     out().PrintTo(f);
   }
 
   if (always_calls()) f->Print(" C");
 }
 
 }  // namespace dart