Use 'override/final' instead of 'virtual' for overridden methods

The patch is generated using clang-tidy misc-use-override check.

This command was used:

  tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
    -checks='-*,misc-use-override' -header-filter='llvm|clang' \
    -j=32 -fix -format

http://reviews.llvm.org/D8925

llvm-svn: 234679
diff --git a/llvm/examples/Kaleidoscope/Chapter7/toy.cpp b/llvm/examples/Kaleidoscope/Chapter7/toy.cpp
index ce5e1dd..53ea51c 100644
--- a/llvm/examples/Kaleidoscope/Chapter7/toy.cpp
+++ b/llvm/examples/Kaleidoscope/Chapter7/toy.cpp
@@ -138,7 +138,7 @@
 
 public:
   NumberExprAST(double val) : Val(val) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// VariableExprAST - Expression class for referencing a variable, like "a".
@@ -148,7 +148,7 @@
 public:
   VariableExprAST(const std::string &name) : Name(name) {}
   const std::string &getName() const { return Name; }
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// UnaryExprAST - Expression class for a unary operator.
@@ -159,7 +159,7 @@
 public:
   UnaryExprAST(char opcode, ExprAST *operand)
       : Opcode(opcode), Operand(operand) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// BinaryExprAST - Expression class for a binary operator.
@@ -170,7 +170,7 @@
 public:
   BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
       : Op(op), LHS(lhs), RHS(rhs) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// CallExprAST - Expression class for function calls.
@@ -181,7 +181,7 @@
 public:
   CallExprAST(const std::string &callee, std::vector<ExprAST *> &args)
       : Callee(callee), Args(args) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// IfExprAST - Expression class for if/then/else.
@@ -191,7 +191,7 @@
 public:
   IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
       : Cond(cond), Then(then), Else(_else) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// ForExprAST - Expression class for for/in.
@@ -203,7 +203,7 @@
   ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
              ExprAST *step, ExprAST *body)
       : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// VarExprAST - Expression class for var/in
@@ -216,7 +216,7 @@
              ExprAST *body)
       : VarNames(varnames), Body(body) {}
 
-  virtual Value *Codegen();
+  Value *Codegen() override;
 };
 
 /// PrototypeAST - This class represents the "prototype" for a function,