Emit unwinding information for TurboFan code.

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

Index: src/compiler/arm/unwinding-info-writer-arm.h
diff --git a/src/compiler/arm/unwinding-info-writer-arm.h b/src/compiler/arm/unwinding-info-writer-arm.h
new file mode 100644
index 0000000000000000000000000000000000000000..d47ca083ae077d84039f9c6c42b15dd602cbd0d3
--- /dev/null
+++ b/src/compiler/arm/unwinding-info-writer-arm.h
@@ -0,0 +1,72 @@
+// 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_ARM_UNWINDING_INFO_WRITER_H_
+#define V8_COMPILER_ARM_UNWINDING_INFO_WRITER_H_
+
+#include "src/eh-frame.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class InstructionBlock;
+
+class UnwindingInfoWriter {
+ public:
+  explicit UnwindingInfoWriter(Zone* zone)
+      : zone_(zone),
+        eh_frame_writer_(zone),
+        saved_lr_(false),
+        block_will_exit_(false),
+        block_initial_states_(zone) {
+    if (enabled()) eh_frame_writer_.Initialize();
+  }
+
+  void SetNumberOfInstructionBlocks(int number) {
+    if (enabled()) block_initial_states_.resize(number);
+  }
+
+  void BeginInstructionBlock(int pc_offset, const InstructionBlock* block);
+  void EndInstructionBlock(const InstructionBlock* block);
+
+  void MarkLinkRegisterOnTopOfStack(int pc_offset);
+  void MarkPopLinkRegisterFromTopOfStack(int pc_offset);
+
+  void MarkFrameConstructed(int at_pc);
+  void MarkFrameDeconstructed(int at_pc);
+
+  void MarkBlockWillExit() { block_will_exit_ = true; }
+
+  void Finish(int code_size) {
+    if (enabled()) eh_frame_writer_.Finish(code_size);
+  }
+
+  EhFrameWriter* eh_frame_writer() {
+    return enabled() ? &eh_frame_writer_ : nullptr;
+  }
+
+ private:
+  bool enabled() const { return FLAG_perf_prof_unwinding_info; }
+
+  class BlockInitialState : public ZoneObject {
+   public:
+    explicit BlockInitialState(bool saved_lr) : saved_lr_(saved_lr) {}
+
+    bool saved_lr_;
+  };
+
+  Zone* zone_;
+  EhFrameWriter eh_frame_writer_;
+  bool saved_lr_;
+  bool block_will_exit_;
+
+  ZoneVector<const BlockInitialState*> block_initial_states_;
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif