Reland Implement .eh_frame writer and disassembler.

test/unittests/eh-frame-iterator-unittest.cc

+// Copyright 2016 the V8 project 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 "src/eh-frame.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Test enabled only on supported architectures.
+#if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_ARM) || \
+    defined(V8_TARGET_ARCH_ARM64)
+
+using namespace v8::internal;
+
+namespace v8 {
+namespace internal {
+
+class EhFrameIteratorTest : public testing::Test {
+ protected:
+  static uint32_t DecodeULEB128(const byte* encoded, int* encoded_size) {
+    return EhFrameIterator::DecodeULEB128(encoded, encoded_size);
+  }
+
+  static int32_t DecodeSLEB128(const byte* encoded, int* encoded_size) {
+    return EhFrameIterator::DecodeSLEB128(encoded, encoded_size);
+  }
+};
+
+}  // namespace internal
+}  // namespace v8
+
+TEST_F(EhFrameIteratorTest, ULEB128Decoding) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  int size = 0;
+  uint32_t value = DecodeULEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(624485, value);
+}
+
+TEST_F(EhFrameIteratorTest, SLEB128DecodingPositive) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  int size = 0;
+  int32_t value = DecodeSLEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(624485, value);
+}
+
+TEST_F(EhFrameIteratorTest, SLEB128DecodingNegative) {
+  static const byte kEncoded[] = {0x9b, 0xf1, 0x59};
+  int size = 0;
+  int32_t value = DecodeSLEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(-624485, value);
+}
+
+#endif