Reland Implement .eh_frame writer and disassembler.

src/x64/eh-frame-x64.h

+// 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.
+
+#ifndef V8_X64_UNWINDING_INFO_X64_H
+#define V8_X64_UNWINDING_INFO_X64_H
+
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kInitialCFARegister = 7;
+static const int kInitialCFAOffset = kInt64Size;
+static const int kDataAlignmentFactor = -8;
+static const int kInitialStateOffsetInCIE = 19;
+
+static const byte kCIE[] = {
+    0x18, 0x00, 0x00, 0x00,  // Size of the CIE
+    0x00, 0x00, 0x00, 0x00,  // CIE identifier, always 0
+    0x03,                    // CIE version 3
+    0x7a, 0x4c, 0x52, 0x00,  // Augmentation string zLR
+    0x01,                    // Code alignment factor: 1
+    0x78,                    // Data alignment factor: -8
+    0x10,                    // Return address register: rip (r16)
+    0x02,                    // Length of augmentation data
+    0xff,                    // No LSDA
+    0x1b,                    // FDE encoding: DW_EH_PE_sdata4 | DW_EH_PE_pcrel
+    // Initial state
+    0x0c, 0x07, 0x08,  // CFA @ rsp+8
+    0x90, 0x01,        // rip saved at CFA-8
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif