Refactor to support multiple outputs in location summary

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)
+                                 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_() {
   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());
   }
+  // 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();
   }
 }
 
 
 LocationSummary* LocationSummary::Make(
     intptr_t input_count,
     Location out,
     LocationSummary::ContainsCall contains_call) {
   LocationSummary* summary = new LocationSummary(input_count, 0, contains_call);
   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;
 }
 
 
 Location Location::RegisterOrConstant(Value* value) {
   ConstantInstr* constant = value->definition()->AsConstant();
   return ((constant != NULL) && Assembler::IsSafe(constant->value()))
       ? Location::Constant(constant->value())
       : Location::RequiresRegister();
 }
@@ skipping 121 matching lines @@
 
   if (temp_count() > 0) {
     f->Print(" [");
     for (intptr_t i = 0; i < temp_count(); i++) {
       if (i != 0) f->Print(", ");
       temp(i).PrintTo(f);
     }
     f->Print("]");
   }
 
-  if (!out().IsInvalid()) {
+  if (!out(0).IsInvalid()) {
     f->Print(" => ");
-    out().PrintTo(f);
+    out(0).PrintTo(f);
   }
 
   if (always_calls()) f->Print(" C");
 }
 
 }  // namespace dart