Emit unwinding information for TurboFan code.

src/compiler/x64/unwinding-info-writer-x64.h

Index: src/compiler/x64/unwinding-info-writer-x64.h
diff --git a/src/compiler/x64/unwinding-info-writer-x64.h b/src/compiler/x64/unwinding-info-writer-x64.h
new file mode 100644
index 0000000000000000000000000000000000000000..23702534eb9841711c232c795fd595f45855d82c
--- /dev/null
+++ b/src/compiler/x64/unwinding-info-writer-x64.h
@@ -0,0 +1,60 @@
+// 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_COMPILER_X64_UNWINDING_INFO_WRITER_H_
+#define V8_COMPILER_X64_UNWINDING_INFO_WRITER_H_
+
+#include <unordered_map>
+#include "src/eh-frame.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class InstructionBlock;
+
+class UnwindingInfoWriter {
+ public:
+  UnwindingInfoWriter() : tracking_fp_(false), block_will_exit_(false) {}
+
+  void MaybeIncreaseFrameBaseOffsetAt(int pc_offset, int base_delta) {
+    if (!tracking_fp_) {
+      eh_frame_writer_.AdvanceLocation(pc_offset);
+      eh_frame_writer_.IncreaseBaseAddressOffset(base_delta);
+    }
+  }
+
+  void BeginInstructionBlock(int pc_offset, const InstructionBlock* block);
+  void EndInstructionBlock(const InstructionBlock* block);
+
+  void MarkFrameConstructed(int pc_base);
+  void MarkFrameDeconstructed(int pc_base);
+
+  void MarkBlockWillExit() { block_will_exit_ = true; }
+
+  void Finish(int code_size) { eh_frame_writer_.Finish(code_size); }
+
+  EhFrameWriter* eh_frame_writer() { return &eh_frame_writer_; }
+
+ private:
+  EhFrameWriter eh_frame_writer_;
+
+  struct BlockInitialState {
+    Register register_;
+    int offset_;
+    bool tracking_fp_;
+  };
+
+  bool tracking_fp_;
+  bool block_will_exit_;
+
+  std::unordered_map<int, BlockInitialState> block_initial_states_;
+  static_assert(kIntSize >= kInt32Size, "int too small to encode a RpoNumber");
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif