Re-apply: Initial check-in of an optimizing compiler.

The classes and the names are very much inspired by V8/Dart.
It currently only supports the RETURN_VOID dex instruction,
and there is a pretty printer to check if the building of the
graph is correct.

Change-Id: I28e125dfee86ae6ec9b3fec6aa1859523b92a893
diff --git a/compiler/optimizing/builder.h b/compiler/optimizing/builder.h
new file mode 100644
index 0000000..3e94fba
--- /dev/null
+++ b/compiler/optimizing/builder.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_COMPILER_OPTIMIZING_BUILDER_H_
+#define ART_COMPILER_OPTIMIZING_BUILDER_H_
+
+#include "utils/allocation.h"
+
+namespace art {
+
+class ArenaAllocator;
+class Instruction;
+class HBasicBlock;
+class HGraph;
+
+class HGraphBuilder : public ValueObject {
+ public:
+  explicit HGraphBuilder(ArenaAllocator* arena)
+      : arena_(arena),
+        entry_block_(nullptr),
+        exit_block_(nullptr),
+        current_block_(nullptr),
+        graph_(nullptr) { }
+
+  HGraph* BuildGraph(const uint16_t* start, const uint16_t* end);
+
+ private:
+  // Analyzes the dex instruction and adds HInstruction to the graph
+  // to execute that instruction. Returns whether the instruction can
+  // be handled.
+  bool AnalyzeDexInstruction(const Instruction& instruction);
+
+  ArenaAllocator* const arena_;
+  HBasicBlock* entry_block_;
+  HBasicBlock* exit_block_;
+  HBasicBlock* current_block_;
+  HGraph* graph_;
+
+  DISALLOW_COPY_AND_ASSIGN(HGraphBuilder);
+};
+
+}  // namespace art
+
+#endif  // ART_COMPILER_OPTIMIZING_BUILDER_H_