"This adds -fconcepts-ts as a cc1 option for enabling the

in-progress implementation of the Concepts TS. The recommended feature
test macro __cpp_experimental_concepts is set to 1 (as opposed to
201501) to indicate that the feature is enabled, but the
implementation is incomplete.

The link to the Concepts TS in cxx_status is updated to refer to the
PDTS (N4377). Additional changes related to __has_feature and
__has_extension are to follow in a later change.

Relevant tests include:

test/Lexer/cxx-features.cpp

The test file is updated with testing of the C++14 + Concepts TS mode.
The expected behaviour is the same as that of the C++14 modes except
for the case of __cpp_experimental_concepts."

- Hubert Tong.

Being committed for Hubert (as per his understanding with Richard Smith) as we start work on the concepts-ts following our preliminary strategy session earlier today. 

The patch is tiny and seems quite standard.

Thanks Hubert!

llvm-svn: 237982

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 0d97709..dfc46f4 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -453,6 +453,8 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
   }
   if (LangOpts.SizedDeallocation)
     Builder.defineMacro("__cpp_sized_deallocation", "201309");
+  if (LangOpts.ConceptsTS)
+    Builder.defineMacro("__cpp_experimental_concepts", "1");
 }
 
 static void InitializePredefinedMacros(const TargetInfo &TI,