Added def-use chain to the intermediate language.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/locations.h"
 #include "vm/object.h"
 #include "vm/os.h"
 #include "vm/scopes.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, enable_type_checks);
 
+UseVal::UseVal(Definition* definition)
+    : definition_(definition), next_use_(NULL), previous_use_(NULL) {
+  AddToDefUseChain();
+}
+
+void UseVal::set_definition(Definition* definition) {
+  ASSERT(definition != NULL);
+  RemoveFromDefUseChain();
+  definition_ = definition;
+  AddToDefUseChain();
+}
+
+void UseVal::RemoveFromDefUseChain() {
+  ASSERT(definition_ != NULL);
+  if (previous_use_ == NULL) {
+    ASSERT(definition_->def_use_chain() == this);
+    definition_->set_def_use_chain(next_use_);
+  } else {
+    previous_use_->next_use_ = next_use_;
+  }
+  if (next_use_ != NULL) {
+    next_use_->previous_use_ = previous_use_;
+  }
+  previous_use_ = next_use_ = NULL;
+  definition_ = NULL;
+}
+
+void UseVal::AddToDefUseChain() {
+  ASSERT(next_use_ == NULL && previous_use_ == NULL && definition_ != NULL);
+  UseVal* chain = definition_->def_use_chain();
+  if (chain != NULL) {
+    next_use_ = chain;
+    chain->previous_use_ = this;
+  }
+  definition_->set_def_use_chain(this);
+}
+
+
+
 
 MethodRecognizer::Kind MethodRecognizer::RecognizeKind(
     const Function& function) {
   // Only core library methods can be recognized.
   const Library& core_lib = Library::Handle(Library::CoreLibrary());
   const Library& core_impl_lib = Library::Handle(Library::CoreImplLibrary());
   const Class& function_class = Class::Handle(function.owner());
   if ((function_class.library() != core_lib.raw()) &&
       (function_class.library() != core_impl_lib.raw())) {
     return kUnknown;
@@ skipping 1177 matching lines @@
         locations_[i] = Location::NoLocation();
       }
     }
   }
 }
 
 
 #undef __
 
 }  // namespace dart