optimized switch implementation

src/wasm/switch-logic.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_WASM_SWITCH_LOGIC_H
+#define V8_WASM_SWITCH_LOGIC_H
+
+#include "src/zone-containers.h"
+#include "src/zone.h"
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+struct CaseNode : public ZoneObject {
+  const int begin;
+  const int end;
+  CaseNode* left;
+  CaseNode* right;
+  CaseNode(int begin, int end) : begin(begin), end(end) {
+    left = nullptr;
+    right = nullptr;
+  }
+};
+
+CaseNode* OrderCases(ZoneVector<int>* cases, Zone* zone);
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+
+#endif