Use lexing mode based on FormatStyle.Standard.

Summary:
Some valid pre-C++11 constructs change meaning when lexed in C++11
mode, e.g.
#define x(_a) printf("foo"_a);
(example from http://llvm.org/bugs/show_bug.cgi?id=16342). "foo"_a is treated as
a user-defined string literal when parsed in C++11 mode.
In order to deal with this correctly, we need to set lexing mode according to
which standard the code conforms to. We already have a configuration value for
this (FormatStyle.Standard), which seems to be appropriate to use in this case
as well.

Reviewers: klimek

CC: cfe-commits, gribozavr

Differential Revision: http://llvm-reviews.chandlerc.com/D1028

llvm-svn: 185149

1 files changed, 5 insertions, 1 deletions

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 24eeb76d068..d03b8796feb 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -218,7 +218,11 @@ tooling::Replacements reformat(const FormatStyle &Style, StringRef Code,
                                StringRef FileName = "<stdin>");
 
 /// \brief Returns the \c LangOpts that the formatter expects you to set.
-LangOptions getFormattingLangOpts();
+///
+/// \param Standard determines lexing mode: LC_Cpp11 and LS_Auto turn on C++11
+/// lexing mode, LS_Cpp03 - C++03 mode.
+LangOptions getFormattingLangOpts(FormatStyle::LanguageStandard Standard =
+                                      FormatStyle::LS_Cpp11);
 
 } // end namespace format
 } // end namespace clang