add overrider for virtual function to avoid warning (#21503)

* add overrider for virtual function; test=develop

* fix layer.h OutputName bug; test=develop

paddle/fluid/imperative/layer.h

@@ -230,14 +230,14 @@ class DygraphExecutionContext : public framework::ExecutionContext {
         var_base_map_out_(var_base_map_out),
         attrs_(attrs) {}
 
-  std::string InputName(const std::string& name) const {
+  std::string InputName(const std::string& name) const override {
     auto it = var_base_map_in_.find(name);
     PADDLE_ENFORCE_NE(it, var_base_map_in_.end(),
                       platform::errors::PreconditionNotMet(
                           "Can not find [%s] in Input", name));
     return it->second[0]->Name();
   }
-  std::vector<std::string> InputNames(const std::string& name) const {
+  std::vector<std::string> InputNames(const std::string& name) const override {
     auto it = var_base_map_in_.find(name);
     PADDLE_ENFORCE_NE(
         it, var_base_map_in_.end(),
@@ -250,7 +250,7 @@ class DygraphExecutionContext : public framework::ExecutionContext {
     return vec_res;
   }
 
-  std::string OuputName(const std::string& name) const {
+  std::string OutputName(const std::string& name) const override {
     auto it = var_base_map_out_.find(name);
     PADDLE_ENFORCE_NE(
         it, var_base_map_out_.end(),
@@ -258,7 +258,7 @@ class DygraphExecutionContext : public framework::ExecutionContext {
     return it->second[0]->Name();
   }
 
-  std::vector<std::string> OutputNames(const std::string& name) const {
+  std::vector<std::string> OutputNames(const std::string& name) const override {
     auto it = var_base_map_out_.find(name);
     PADDLE_ENFORCE_NE(
         it, var_base_map_out_.end(),
@@ -271,11 +271,13 @@ class DygraphExecutionContext : public framework::ExecutionContext {
     return vec_res;
   }
 
-  bool HasAttr(const std::string& name) const { return attrs_->count(name); }
+  bool HasAttr(const std::string& name) const override {
+    return attrs_->count(name);
+  }
 
-  const framework::AttributeMap& Attrs() const { return *attrs_; }
+  const framework::AttributeMap& Attrs() const override { return *attrs_; }
 
-  const framework::Attribute& GetAttr(const std::string& name) const {
+  const framework::Attribute& GetAttr(const std::string& name) const override {
     auto it = attrs_->find(name);
 
     PADDLE_ENFORCE_NE(
@@ -285,7 +287,7 @@ class DygraphExecutionContext : public framework::ExecutionContext {
     return it->second;
   }
 
-  std::vector<std::string> InNameList() const {
+  std::vector<std::string> InNameList() const override {
     std::vector<std::string> vec_temp;
     vec_temp.reserve(var_base_map_in_.size());
 
@@ -295,21 +297,21 @@ class DygraphExecutionContext : public framework::ExecutionContext {
 
     return vec_temp;
   }
-  bool HasInput(const std::string& name) const {
+  bool HasInput(const std::string& name) const override {
     auto it = var_base_map_in_.find(name);
     return (it != var_base_map_in_.end() && it->second.size() > 0);
   }
 
-  virtual bool HasOutput(const std::string& name) const {
+  bool HasOutput(const std::string& name) const override {
     auto it = var_base_map_out_.find(name);
     return (it != var_base_map_out_.end() && it->second.size() > 0);
   }
 
-  size_t InputSize(const std::string& name) const {
+  size_t InputSize(const std::string& name) const override {
     return InputNames(name).size();
   }
 
-  size_t OutputSize(const std::string& name) const {
+  size_t OutputSize(const std::string& name) const override {
     return OutputNames(name).size();
   }
 
@@ -322,7 +324,7 @@ class DygraphExecutionContext : public framework::ExecutionContext {
     return it->second.empty() ? nullptr : it->second[0]->MutableVar();
   }
 
-  Variable* OutputVar(const std::string& name) const {
+  Variable* OutputVar(const std::string& name) const override {
     auto it = var_base_map_out_.find(name);
     if (it == var_base_map_out_.end()) {
       return nullptr;