Add a host tool to pack R_ARM_RELATIVE relocations in libchrome.<ver>.so.

tools/relocation_packer/src/run_length_encoder_unittest.cc

+// Copyright 2014 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 "run_length_encoder.h"
+
+#include <vector>
+#include "elf.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+void AddRelocation(Elf32_Addr addr, std::vector<Elf32_Rel>* relocations) {
+  Elf32_Rel relocation = {addr, R_ARM_RELATIVE};
+  relocations->push_back(relocation);
+}
+
+bool CheckRelocation(Elf32_Addr addr, const Elf32_Rel& relocation) {
+  return relocation.r_offset == addr && relocation.r_info == R_ARM_RELATIVE;
+}
+
+}  // namespace
+
+namespace relocation_packer {
+
+TEST(Rle, Encode) {
+  std::vector<Elf32_Rel> relocations;
+  std::vector<Elf32_Word> packed;
+
+  RelocationRunLengthCodec codec;
+
+  packed.clear();
+  codec.Encode(relocations, &packed);
+
+  EXPECT_EQ(0u, packed.size());
+
+  // Add one relocation (insufficient data to encode).
+  AddRelocation(0xf00d0000, &relocations);
+
+  packed.clear();
+  codec.Encode(relocations, &packed);
+
+  EXPECT_EQ(0u, packed.size());
+
+  // Add a second relocation, 4 byte delta (minimum data to encode).
+  AddRelocation(0xf00d0004, &relocations);
+
+  packed.clear();
+  codec.Encode(relocations, &packed);
+
+  EXPECT_EQ(4u, packed.size());
+  // One count-delta pair present.
+  EXPECT_EQ(1u, packed[0]);
+  // Initial relocation.
+  EXPECT_EQ(0xf00d0000, packed[1]);
+  // Run of a single relocation, 4 byte delta.
+  EXPECT_EQ(1u, packed[2]);
+  EXPECT_EQ(4u, packed[3]);
+
+  // Add a third relocation, 4 byte delta.
+  AddRelocation(0xf00d0008, &relocations);
+
+  // Add three more relocations, 8 byte deltas.
+  AddRelocation(0xf00d0010, &relocations);
+  AddRelocation(0xf00d0018, &relocations);
+  AddRelocation(0xf00d0020, &relocations);
+
+  packed.clear();
+  codec.Encode(relocations, &packed);
+
+  EXPECT_EQ(6u, packed.size());
+  // Two count-delta pairs present.
+  EXPECT_EQ(2u, packed[0]);
+  // Initial relocation.
+  EXPECT_EQ(0xf00d0000, packed[1]);
+  // Run of two relocations, 4 byte deltas.
+  EXPECT_EQ(2u, packed[2]);
+  EXPECT_EQ(4u, packed[3]);
+  // Run of three relocations, 8 byte deltas.
+  EXPECT_EQ(3u, packed[4]);
+  EXPECT_EQ(8u, packed[5]);
+}
+
+TEST(Rle, Decode) {
+  std::vector<Elf32_Word> packed;
+  std::vector<Elf32_Rel> relocations;
+
+  RelocationRunLengthCodec codec;
+  codec.Decode(packed, &relocations);
+
+  EXPECT_EQ(0u, relocations.size());
+
+  // Two count-delta pairs.
+  packed.push_back(2u);
+  // Initial relocation.
+  packed.push_back(0xc0de0000);
+  // Run of two relocations, 4 byte deltas.
+  packed.push_back(2u);
+  packed.push_back(4u);
+  // Run of three relocations, 8 byte deltas.
+  packed.push_back(3u);
+  packed.push_back(8u);
+
+  relocations.clear();
+  codec.Decode(packed, &relocations);
+
+  EXPECT_EQ(6u, relocations.size());
+  // Initial relocation.
+  EXPECT_TRUE(CheckRelocation(0xc0de0000, relocations[0]));
+  // Two relocations, 4 byte deltas.
+  EXPECT_TRUE(CheckRelocation(0xc0de0004, relocations[1]));
+  EXPECT_TRUE(CheckRelocation(0xc0de0008, relocations[2]));
+  // Three relocations, 8 byte deltas.
+  EXPECT_TRUE(CheckRelocation(0xc0de0010, relocations[3]));
+  EXPECT_TRUE(CheckRelocation(0xc0de0018, relocations[4]));
+  EXPECT_TRUE(CheckRelocation(0xc0de0020, relocations[5]));
+}
+
+}  // namespace relocation_packer