Initial, rudimentary implementation of operator overloading for binary
operators. For example, one can now write "x + y" where x or y is a
class or enumeration type, and Clang will perform overload resolution
for "+" based on the overloaded operators it finds.

The other kinds of overloadable operators in C++ will follow this same
approach. 

Three major issues remain:
  1) We don't find member operators
  2) Since we don't have user-defined conversion operators, we can't
  call any of the built-in overloaded operators in C++ [over.built].
  3) Once we've done the semantic checks, we drop the overloaded
  operator on the floor; it doesn't get into the AST at all.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58821 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index cc2e3f2..f9dd257 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -630,9 +630,13 @@
                                    InitListDesignations &Designators,
                                    SourceLocation RParenLoc);
                                    
-  virtual ExprResult ActOnBinOp(SourceLocation TokLoc, tok::TokenKind Kind,
+  virtual ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc, 
+                                tok::TokenKind Kind,
                                 ExprTy *LHS,ExprTy *RHS);
-  
+  ExprResult CreateBuiltinBinOp(SourceLocation TokLoc, 
+                                unsigned Opc,
+                                Expr *lhs, Expr *rhs);
+
   /// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
   /// in the case of a the GNU conditional expr extension.
   virtual ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,