Make Value not a subclass of Computation.

runtime/vm/flow_graph.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.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/intermediate_language.h"
 #include "vm/longjump.h"
@@ skipping 253 matching lines @@
 
   // Initialize start environment.
   GrowableArray<Definition*> start_env(variable_count());
   for (intptr_t i = 0; i < parameter_count(); ++i) {
     ParameterInstr* param = new ParameterInstr(i);
     param->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
     start_env.Add(param);
   }
 
   // All locals are initialized with #null.
-  Definition* null_defn = new BindInstr(BindInstr::kUsed,
-                                        new ConstantVal(Object::ZoneHandle()));
+  Definition* null_defn =
+      new BindInstr(BindInstr::kUsed,
+                    new MaterializeComp(new ConstantVal(Object::ZoneHandle())));
   // The null definition should not appear in input positions.
   ASSERT(null_defn->ssa_temp_index() == -1);
   while (start_env.length() < variable_count()) {
     start_env.Add(null_defn);
   }
   graph_entry_->set_start_env(
       new Environment(start_env, non_copied_parameter_count_));
 
   BlockEntryInstr* normal_entry = graph_entry_->SuccessorAt(0);
   ASSERT(normal_entry != NULL);  // Must have entry.
   GrowableArray<Definition*> env(variable_count());
   env.AddArray(start_env);
   RenameRecursive(normal_entry, &env, live_phis);
 }
 
 
 // Helper to either use the constant value of a definition or the definition.
 static Value* UseDefinition(Definition* defn) {
-  if (defn->IsBind() && defn->AsBind()->computation()->IsConstant()) {
-    return defn->AsBind()->computation()->AsConstant();
+  if (defn->IsBind() && defn->AsBind()->computation()->IsMaterialize()) {
+    return defn->AsBind()->computation()->AsMaterialize()->constant_val();
   } else {
     return new UseVal(defn);
   }
 }
 
 
 void FlowGraph::RenameRecursive(BlockEntryInstr* block_entry,
                                 GrowableArray<Definition*>* env,
                                 GrowableArray<PhiInstr*>* live_phis) {
   // 1. Process phis first.
@@ skipping 157 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart