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/Serialization/ASTReaderStmt.cpp b/lib/Serialization/ASTReaderStmt.cpp
index 73b5ab7..9eda98c 100644
--- a/lib/Serialization/ASTReaderStmt.cpp
+++ b/lib/Serialization/ASTReaderStmt.cpp
@@ -1074,7 +1074,8 @@
 
 void ASTStmtReader::VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
   VisitCallExpr(E);
-  E->setOperator((OverloadedOperatorKind)Record[Idx++]);
+  E->Operator = (OverloadedOperatorKind)Record[Idx++];
+  E->Range = Reader.ReadSourceRange(F, Record, Idx);
 }
 
 void ASTStmtReader::VisitCXXConstructExpr(CXXConstructExpr *E) {