Refactor to support multiple outputs in location summary

runtime/vm/locations.cc

Index: runtime/vm/locations.cc
diff --git a/runtime/vm/locations.cc b/runtime/vm/locations.cc
index e5d0fab186b7863339dbaceeafd1af02d3aa48b9..48fb2416b82bcaeb4ee720f1ff151d39fef20576 100644
--- a/runtime/vm/locations.cc
+++ b/runtime/vm/locations.cc
@@ -25,10 +25,11 @@ intptr_t RegisterSet::RegisterCount(intptr_t registers) {
 
 LocationSummary::LocationSummary(intptr_t input_count,
                                  intptr_t temp_count,
-                                 LocationSummary::ContainsCall contains_call)
+                                 LocationSummary::ContainsCall contains_call,
+                                 intptr_t output_count)
     : input_locations_(input_count),
       temp_locations_(temp_count),
-      output_location_(),
+      output_locations_(output_count),
       stack_bitmap_(NULL),
       contains_call_(contains_call),
       live_registers_() {
@@ -38,6 +39,11 @@ LocationSummary::LocationSummary(intptr_t input_count,
   for (intptr_t i = 0; i < temp_count; i++) {
     temp_locations_.Add(Location());
   }
+  // TODO(johnmccutchan): Remove this assertion.
+  ASSERT(output_count == 1);
+  for (intptr_t i = 0; i < output_count; i++) {
+    output_locations_.Add(Location());
+  }
 
   if (contains_call_ != kNoCall) {
     stack_bitmap_ = new BitmapBuilder();
@@ -53,7 +59,7 @@ LocationSummary* LocationSummary::Make(
   for (intptr_t i = 0; i < input_count; i++) {
     summary->set_in(i, Location::RequiresRegister());
   }
-  summary->set_out(out);
+  summary->set_out(0, out);
   return summary;
 }
 
@@ -195,9 +201,9 @@ void LocationSummary::PrintTo(BufferFormatter* f) const {
     f->Print("]");
   }
 
-  if (!out().IsInvalid()) {
+  if (!out(0).IsInvalid()) {
     f->Print(" => ");
-    out().PrintTo(f);
+    out(0).PrintTo(f);
   }
 
   if (always_calls()) f->Print(" C");