[OpenCL] Allow for variadic macros in C++ for OpenCL

[olestrohm]

Summary

C++ for OpenCL intends to support variadic macros, a decision motivated by OpenCL 3.0. This patch simply skips the warning when compiling in C++ for OpenCL mode.

[Anastasia]

Can you extend test test/Preprocessor/macro_variadic.cl to cover C++ for OpenCL mode, otherwise LGTM!

[olestrohm]

I have amended the relevant test to validate this behaviour in C++ for OpenCL.

[Anastasia]

LGTM! Thanks

clang/lib/Lex/PPDirectives.cpp

case tok::r_paren:
       return true;
     case tok::ellipsis:  // #define X(... -> C99 varargs
       if (!LangOpts.C99)
         Diag(Tok, LangOpts.CPlusPlus11 ?
              diag::warn_cxx98_compat_variadic_macro :
              diag::ext_variadic_macro);
 
       // OpenCL v1.2 s6.9.e: variadic macros are not supported.
-      if (LangOpts.OpenCL) {
+      if (LangOpts.OpenCL && !LangOpts.OpenCLCPlusPlus) {
         Diag(Tok, diag::ext_pp_opencl_variadic_macros);
       }
 
       // Lex the token after the identifier.
       LexUnexpandedToken(Tok);
       if (Tok.isNot(tok::r_paren)) {
         Diag(Tok, diag::err_pp_missing_rparen_in_macro_def);
         return true;

clang/test/Preprocessor/macro_variadic.cl

 // RUN: %clang_cc1 -verify %s -cl-std=CL1.2
 // RUN: %clang_cc1 -verify %s -pedantic -DPEDANTIC -cl-std=CL1.2
+// RUN: %clang_cc1 -verify %s -cl-std=CLC++
+// RUN: %clang_cc1 -verify %s -pedantic -cl-std=CLC++
 
 
 #define NO_VAR_FUNC(...)  5
 #define VAR_FUNC(...) func(__VA_ARGS__);
 #define VAR_PRINTF(str, ...) printf(str, __VA_ARGS__);
 #ifdef PEDANTIC
 // expected-warning@-4{{variadic macros are a Clang extension in OpenCL}}
 // expected-warning@-4{{variadic macros are a Clang extension in OpenCL}}
 // expected-warning@-4{{variadic macros are a Clang extension in OpenCL}}
 #endif
 
 int printf(__constant const char *st, ...);
 
 void foo() {
   NO_VAR_FUNC(1, 2, 3);
-  VAR_FUNC(1, 2, 3); //expected-error{{implicit declaration of function 'func' is invalid in OpenCL}}
+  VAR_FUNC(1, 2, 3);
+#if !__OPENCL_CPP_VERSION__
+// expected-error@-2{{implicit declaration of function 'func' is invalid in OpenCL}}
+#else
+// expected-error@-4{{use of undeclared identifier 'func'}}
+#endif
   VAR_PRINTF("%i", 1);
 }