Allocate the environment's location backing store during register allocation.

runtime/vm/flow_graph_allocator.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/flow_graph_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 644 matching lines @@
     // Any value mentioned in the deoptimization environment should survive
     // until the end of instruction but it does not need to be in the register.
     // Expected shape of live range:
     //
     //                 i  i'
     //      value    -----*
     //
 
     Environment* env = current->env();
     const GrowableArray<Value*>& values = env->values();
-
+    env->InitializeLocations();

[srdjan, 2012/08/06 22:49:25]

I would move the loop below into InitializeLocation. Since InitializeLocations
only allocates locations, initialization is occurring below.

     for (intptr_t j = 0; j < values.length(); j++) {
       Value* val = values[j];
+      Location* loc = env->LocationSlotAt(j);
       if (val->IsUse()) {
-        env->AddLocation(Location::Any());
+        *loc = Location::Any();
         const intptr_t vreg = val->AsUse()->definition()->ssa_temp_index();
 
         LiveRange* range = GetLiveRange(vreg);
         range->AddUseInterval(block->start_pos(), pos + 1);
-        range->AddUse(pos + 1, env->LocationSlotAt(j));
+        range->AddUse(pos + 1, loc);
       } else {
         ASSERT(val->IsConstant());
-        env->AddLocation(Location::NoLocation());
+        *loc = Location::NoLocation();
       }
     }
   }
 
   // Process inputs.
   // Skip the first input if output is specified with kSameAsFirstInput policy,
   // they will be processed together at the very end.
   for (intptr_t j = output_same_as_first_input ? 1 : 0;
        j < current->InputCount();
        j++) {
@@ skipping 1194 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(Function::Handle(), block_order_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart