[Driver] Add -fno-digraphs

Summary: Add a flag `-fno-digraphs` to disable digraphs in the lexer, similar to `-fno-operator-names` which disables alternative names for C++ operators.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: rsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D48266

llvm-svn: 337232

2 files changed, 3 insertions, 0 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 472a4163e55..853f9a422f1 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3925,6 +3925,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // Forward -f (flag) options which we can pass directly.
   Args.AddLastArg(CmdArgs, options::OPT_femit_all_decls);
   Args.AddLastArg(CmdArgs, options::OPT_fheinous_gnu_extensions);
+  Args.AddLastArg(CmdArgs, options::OPT_fdigraphs, options::OPT_fno_digraphs);
   Args.AddLastArg(CmdArgs, options::OPT_fno_operator_names);
   Args.AddLastArg(CmdArgs, options::OPT_femulated_tls,
                   options::OPT_fno_emulated_tls);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index f57f23a0d4c..d62429dc788 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2173,6 +2173,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.GNUKeywords = Args.hasFlag(OPT_fgnu_keywords, OPT_fno_gnu_keywords,
                                   Opts.GNUKeywords);
 
+  Opts.Digraphs = Args.hasFlag(OPT_fdigraphs, OPT_fno_digraphs, Opts.Digraphs);
+
   if (Args.hasArg(OPT_fno_operator_names))
     Opts.CXXOperatorNames = 0;