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

tools/relocation_packer/src/packer_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 "packer.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(Packer, Pack) {
+  std::vector<Elf32_Rel> relocations;
+  std::vector<uint8_t> packed;
+
+  RelocationPacker packer;
+
+  // Initial relocation.
+  AddRelocation(0xd1ce0000, &relocations);
+  // Two more relocations, 4 byte deltas.
+  AddRelocation(0xd1ce0004, &relocations);
+  AddRelocation(0xd1ce0008, &relocations);
+  // Three more relocations, 8 byte deltas.
+  AddRelocation(0xd1ce0010, &relocations);
+  AddRelocation(0xd1ce0018, &relocations);
+  AddRelocation(0xd1ce0020, &relocations);
+
+  packed.clear();
+  packer.PackRelativeRelocations(relocations, &packed);
+
+  EXPECT_EQ(16u, packed.size());
+  // Identifier.
+  EXPECT_EQ('A', packed[0]);
+  EXPECT_EQ('P', packed[1]);
+  EXPECT_EQ('R', packed[2]);
+  EXPECT_EQ('1', packed[3]);
+  // Count-delta pairs count.
+  EXPECT_EQ(2u, packed[4]);
+  // 0xd1ce0000
+  EXPECT_EQ(128u, packed[5]);
+  EXPECT_EQ(128u, packed[6]);
+  EXPECT_EQ(184u, packed[7]);
+  EXPECT_EQ(142u, packed[8]);
+  EXPECT_EQ(13u, packed[9]);
+  // Run of two relocations, 4 byte deltas.
+  EXPECT_EQ(2u, packed[10]);
+  EXPECT_EQ(4u, packed[11]);
+  // Run of three relocations, 8 byte deltas.
+  EXPECT_EQ(3u, packed[12]);
+  EXPECT_EQ(8u, packed[13]);
+  // Padding.
+  EXPECT_EQ(0u, packed[14]);
+  EXPECT_EQ(0u, packed[15]);
+}
+
+TEST(Packer, Unpack) {
+  std::vector<uint8_t> packed;
+  std::vector<Elf32_Rel> relocations;
+
+  RelocationPacker packer;
+
+  // Identifier.
+  packed.push_back('A');
+  packed.push_back('P');
+  packed.push_back('R');
+  packed.push_back('1');
+  // Count-delta pairs count.
+  packed.push_back(2u);
+  // 0xd1ce0000
+  packed.push_back(128u);
+  packed.push_back(128u);
+  packed.push_back(184u);
+  packed.push_back(142u);
+  packed.push_back(13u);
+  // 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);
+  // Padding.
+  packed.push_back(0u);
+  packed.push_back(0u);
+
+  relocations.clear();
+  packer.UnpackRelativeRelocations(packed, &relocations);
+
+  EXPECT_EQ(6u, relocations.size());
+  // Initial relocation.
+  EXPECT_TRUE(CheckRelocation(0xd1ce0000, relocations[0]));
+  // Two relocations, 4 byte deltas.
+  EXPECT_TRUE(CheckRelocation(0xd1ce0004, relocations[1]));
+  EXPECT_TRUE(CheckRelocation(0xd1ce0008, relocations[2]));
+  // Three relocations, 8 byte deltas.
+  EXPECT_TRUE(CheckRelocation(0xd1ce0010, relocations[3]));
+  EXPECT_TRUE(CheckRelocation(0xd1ce0018, relocations[4]));
+  EXPECT_TRUE(CheckRelocation(0xd1ce0020, relocations[5]));
+}
+
+}  // namespace relocation_packer