[Zucchini] Add DEX Reference read / write for basic types.

(Committing on behalf of etiennep@).

This CL adds DEX References read / write for 11 basic types. Details:
- Add InstructionParser to visit DEX instructions in the insns member
  of a CodeItem, taking care to skip non-instruction "payloads".
- Add InstructionReferenceReader to visit CodeItem References found in
  |[lo, hi)|, using provided callbacks to apply type filters and
  extract targets.
- Add ItemReferenceReader to visit fixed-sized items to extract
  Referenes from a "member variable of interest", using a callback
  to extract targets.
- DisassemblerDex: Add MakeRead*() and MakeWrite*() to return a visitor
  to read / write supported DEX References.
- Add DEX unit test to audit the error-prone look-up table from
  DisassemblerDex::MakeReferenceGroups().

Change-Id: Ice12a867aab4fdcb4a152bb1946ea7515ad426ef
Reviewed-on: https://chromium-review.googlesource.com/994066
Reviewed-by: Samuel Huang <huangs@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549178}
NOKEYCHECK=True
GitOrigin-RevId: 7b249ec48aa0f1058496a1b7f095b0f126011bf6

1 files changed, 51 insertions, 0 deletions

diff --git a/disassembler_dex_unittest.cc b/disassembler_dex_unittest.cc
new file mode 100644
index 0000000..04fe6eb
--- /dev/null
+++ b/disassembler_dex_unittest.cc
@@ -0,0 +1,51 @@
+// 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.
+
+#include "components/zucchini/disassembler_dex.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <algorithm>
+#include <set>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace zucchini {
+
+namespace {
+
+template <typename T>
+size_t CountDistinct(const std::vector<T>& v) {
+  return std::set<T>(v.begin(), v.end()).size();
+}
+
+}  // namespace
+
+// Ensures that ReferenceGroups from DisassemblerDex::MakeReferenceGroups()
+// cover each non-sentinel element in ReferenceType in order, exactly once. Also
+// ensures that the ReferenceType elements are grouped by ReferencePool, and
+// listed in increasing order.
+TEST(DisassemblerDexTest, ReferenceGroups) {
+  std::vector<uint32_t> pool_list;
+  std::vector<uint32_t> type_list;
+  DisassemblerDex dis;
+  for (ReferenceGroup group : dis.MakeReferenceGroups()) {
+    pool_list.push_back(static_cast<uint32_t>(group.pool_tag().value()));
+    type_list.push_back(static_cast<uint32_t>(group.type_tag().value()));
+  }
+
+  // Check ReferenceByte coverage.
+  constexpr size_t kNumTypes = DisassemblerDex::kNumTypes;
+  EXPECT_EQ(kNumTypes, type_list.size());
+  EXPECT_EQ(kNumTypes, CountDistinct(type_list));
+  EXPECT_TRUE(std::is_sorted(type_list.begin(), type_list.end()));
+
+  // Check that ReferenceType elements are grouped by ReferencePool. Note that
+  // repeats can occur, and pools can be skipped.
+  EXPECT_TRUE(std::is_sorted(pool_list.begin(), pool_list.end()));
+}
+
+}  // namespace zucchini