Store the source range of a CXXOperatorCallExpr in the Expr object instead of
calculating it recursively.

boost::assign::tuple_list_of uses the trick of chaining call operator expressions in order to declare a "list of tuples", e.g:
    std::vector<tuple> v = boost::assign::tuple_list_of(1, "foo")(2, "bar")(3, "qqq");

Due to CXXOperatorCallExpr calculating its source range recursively we would get
significant slowdowns with a large number of chained call operator expressions and the
potential for stack overflow.

rdar://11350116

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155848 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index 8cf519c..8fbe721 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -415,7 +415,7 @@
   return SourceRange(Loc, End);
 }
 
-SourceRange CXXOperatorCallExpr::getSourceRange() const {
+SourceRange CXXOperatorCallExpr::getSourceRangeImpl() const {
   OverloadedOperatorKind Kind = getOperator();
   if (Kind == OO_PlusPlus || Kind == OO_MinusMinus) {
     if (getNumArgs() == 1)
@@ -438,7 +438,7 @@
     return SourceRange(getArg(0)->getSourceRange().getBegin(),
                        getArg(1)->getSourceRange().getEnd());
   } else {
-    return SourceRange();
+    return getOperatorLoc();
   }
 }