[Zucchini] Create dex disassembler.

Creates Disassembler that recognises and parses DEX format. For now, it doesn't
extract any type reference, so it is equivalent to DisassemblerNoOp. Extraction
of various types of reference will be added in a follow-up CL.
BufferView::covers_array() and unittests were also added.

Change-Id: I08756244e9af899cf0f40dabd2b0059e1749328e
Reviewed-on: https://chromium-review.googlesource.com/967603
Reviewed-by: Samuel Huang <huangs@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546807}
NOKEYCHECK=True
GitOrigin-RevId: d214e2cf9e23bf055f0e0655e9564761d50206ad

1 files changed, 65 insertions, 0 deletions

diff --git a/disassembler_dex.h b/disassembler_dex.h
new file mode 100644
index 0000000..7bbe5d1
--- /dev/null
+++ b/disassembler_dex.h
@@ -0,0 +1,65 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_ZUCCHINI_DISASSEMBLER_DEX_H_
+#define COMPONENTS_ZUCCHINI_DISASSEMBLER_DEX_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "components/zucchini/disassembler.h"
+#include "components/zucchini/image_utils.h"
+#include "components/zucchini/type_dex.h"
+
+namespace zucchini {
+
+// For consistency, let "canonical order" of DEX data types be the order defined
+// in https://source.android.com/devices/tech/dalvik/dex-format "Type Codes"
+// section.
+
+class DisassemblerDex : public Disassembler {
+ public:
+  DisassemblerDex();
+  ~DisassemblerDex() override;
+
+  // Applies quick checks to determine if |image| *may* point to the start of an
+  // executable. Returns true on success.
+  static bool QuickDetect(ConstBufferView image);
+
+  // Disassembler:
+  ExecutableType GetExeType() const override;
+  std::string GetExeTypeString() const override;
+  std::vector<ReferenceGroup> MakeReferenceGroups() const override;
+
+ private:
+  friend Disassembler;
+  using MapItemMap = std::map<uint16_t, const dex::MapItem*>;
+
+  // Disassembler:
+  bool Parse(ConstBufferView image) override;
+
+  bool ParseHeader();
+
+  const dex::HeaderItem* header_ = nullptr;
+  int dex_version_ = 0;
+  MapItemMap map_item_map_ = {};
+  dex::MapItem string_map_item_ = {};
+  dex::MapItem type_map_item_ = {};
+  dex::MapItem field_map_item_ = {};
+  dex::MapItem method_map_item_ = {};
+  dex::MapItem code_map_item_ = {};
+
+  // Sorted list of offsets of code items in |image_|.
+  std::vector<offset_t> code_item_offsets_;
+
+  DISALLOW_COPY_AND_ASSIGN(DisassemblerDex);
+};
+
+}  // namespace zucchini
+
+#endif  // COMPONENTS_ZUCCHINI_DISASSEMBLER_DEX_H_