Templatize AstVisitor with its subclass

src/asmjs/typing-asm.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_ASMJS_TYPING_ASM_H_
 #define V8_ASMJS_TYPING_ASM_H_
 
 #include "src/allocation.h"
 #include "src/ast/ast-type-bounds.h"
 #include "src/ast/ast.h"
 #include "src/effects.h"
 #include "src/type-info.h"
 #include "src/types.h"
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 class TypeCache;
 
-class AsmTyper : public AstVisitor {
+class AsmTyper final : public AstVisitor<AsmTyper> {
  public:
   explicit AsmTyper(Isolate* isolate, Zone* zone, Script* script,
                     FunctionLiteral* root);
   bool Validate();
   void set_allow_simd(bool simd) { allow_simd_ = simd; }
   void set_fixed_signature(bool fixed) { fixed_signature_ = fixed; }
   const char* error_message() { return error_message_; }
   const AstTypeBounds* bounds() { return &bounds_; }
 
   enum StandardMember {
@@ skipping 93 matching lines @@
 
   static const int kErrorMessageLimit = 150;
   char error_message_[kErrorMessageLimit];
 
   static const int kMaxUncombinedAdditiveSteps = 1 << 20;
   static const int kMaxUncombinedMultiplicativeSteps = 1;
 
   void InitializeStdlib();
   void InitializeStdlibSIMD();
 
-  void VisitDeclarations(ZoneList<Declaration*>* d) override;
-  void VisitStatements(ZoneList<Statement*>* s) override;
+  void VisitDeclarations(ZoneList<Declaration*>* d);
+  void VisitStatements(ZoneList<Statement*>* s);
 
   void VisitExpressionAnnotation(Expression* e, Variable* var, bool is_return);
   void VisitFunctionAnnotation(FunctionLiteral* f);
   void VisitAsmModule(FunctionLiteral* f);
 
   void VisitHeapAccess(Property* expr, bool assigning, Type* assignment_type);
 
   void CheckPolymorphicStdlibArguments(enum StandardMember standard_member,
                                        ZoneList<Expression*>* args);
 
@@ skipping 24 matching lines @@
                             const char* msg);
 
   void VisitLiteral(Literal* expr, bool is_return);
 
   void VisitIntegerBitwiseOperator(BinaryOperation* expr, Type* left_expected,
                                    Type* right_expected, Type* result_type,
                                    bool conversion);
 
   Zone* zone() const { return zone_; }
 
-#define DECLARE_VISIT(type) void Visit##type(type* node) override;
+#define DECLARE_VISIT(type) void Visit##type(type* node);
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   DISALLOW_COPY_AND_ASSIGN(AsmTyper);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TYPING_ASM_H_