This reverts commit f4537935dc.
This reverts commit b43c26d036.
This GNU and MSVC extension turns out to be very popular. Most projects
are not using C++20, so cannot use the new __VA_OPT__ feature to be
standards conformant. The other workaround, using -std=gnu*, enables too
many language extensions and isn't viable.
Until there is a way for users to get the behavior provided by the
`, ## __VA_ARGS__` extension in the -std=c++17 and earlier language
modes, we need to revert this.
As noted in D91913, MSVC implements the GNU behavior for
, ## __VA_ARGS__ as well. Do the same when `-fms-compatibility` is used.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D95392
The GNU token paste extension that removes the comma in , ## __VA_ARGS__
conflicts with C99/C++11's requirements when a variadic macro has no
named parameters: according to the standard, an invocation as FOO()
gives it a single empty argument, and concatenation of anything with an
empty argument is well-defined. For this reason, the GNU extension was
already disabled in C99 standard-conforming mode. It was not yet
disabled in C++11 standard-conforming mode.
The associated comment suggested that GCC keeps this extension enabled
in C90/C++03 standard-conforming mode, but it actually does not, so
rather than adding a check for C++ language version, this change simply
removes the check for C language version.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D91913
is empty in a variadic macro expansion. This fixes a divergence in support for
the ", ## __VA_ARGS__" GCC extension which differed in behaviour when in strict
C99 mode (note: there is no change in behaviour has been made in the gnu99 mode
that clang uses by default). In addition, there is improved support for the
Microsoft alternative extension ", __VA_ARGS__".
llvm-svn: 167613
Reid Kleckner