Calculate blocks needing a frame and frame (de)construction sites.

src/compiler/frame-elider.h

+// Copyright 2015 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_FRAME_ELIDER_H_
+#define V8_COMPILER_FRAME_ELIDER_H_
+
+#include "src/compiler/instruction.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+
+// Determine which instruction blocks need a frame and where frames must be
+// constructed/deconstructed.
+class FrameElider {
+ public:
+  explicit FrameElider(InstructionSequence* code);
+  void Run();
+
+
+ private:
+  void MarkBlocks();
+  void PropagateMarks();
+  void MarkDeConstruction();
+  bool PropagateInOrder();
+  bool PropagateReversed();
+  bool PropagateIntoBlock(InstructionBlock* block);
+  const InstructionBlocks& instruction_blocks() const;
+  InstructionBlock* InstructionBlockAt(RpoNumber rpo_number) const;
+  Instruction* InstructionAt(int index) const;
+
+  InstructionSequence* const code_;
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_FRAME_ELIDER_H_