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diff --git a/js/src/frontend/LabelEmitter.h b/js/src/frontend/LabelEmitter.h
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+++ b/js/src/frontend/LabelEmitter.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef frontend_LabelEmitter_h
+#define frontend_LabelEmitter_h
+
+#include "mozilla/Attributes.h"  // MOZ_MUST_USE, MOZ_STACK_CLASS
+#include "mozilla/Maybe.h"       // Maybe
+
+#include "frontend/BytecodeControlStructures.h"  // LabelControl
+#include "frontend/BytecodeOffset.h"             // BytecodeOffset
+#include "frontend/JumpList.h"                   // JumpList
+#include "js/TypeDecls.h"                        // JSAtom
+
+namespace js {
+namespace frontend {
+
+struct BytecodeEmitter;
+
+// Class for emitting labeled statement.
+//
+// Usage: (check for the return value is omitted for simplicity)
+//
+//   `label: expr;`
+//     LabelEmitter le(this);
+//     le.emitLabel(name_of_label);
+//     emit(expr);
+//     le.emitEnd();
+//
+class MOZ_STACK_CLASS LabelEmitter {
+  BytecodeEmitter* bce_;
+
+  mozilla::Maybe<LabelControl> controlInfo_;
+
+#ifdef DEBUG
+  // The state of this emitter.
+  //
+  // +-------+ emitLabel +-------+ emitEnd +-----+
+  // | Start |---------->| Label |-------->| End |
+  // +-------+           +-------+         +-----+
+  enum class State {
+    // The initial state.
+    Start,
+
+    // After calling emitLabel.
+    Label,
+
+    // After calling emitEnd.
+    End
+  };
+  State state_ = State::Start;
+#endif
+
+ public:
+  explicit LabelEmitter(BytecodeEmitter* bce) : bce_(bce) {}
+
+  void emitLabel(const ParserAtom* name);
+  MOZ_MUST_USE bool emitEnd();
+};
+
+} /* namespace frontend */
+} /* namespace js */
+
+#endif /* frontend_LabelEmitter_h */