[PATCH] D157331: [clang] Implement C23 <stdckdint.h>

Wed Oct 18 00:00:47 PDT 2023

mstorsjo added a comment.

This change broke building a recent version of gettext. Gettext uses gnulib for polyfilling various utility functions. Since not long ago, these functions internally use `<stdckdint.h>`, https://git.savannah.gnu.org/cgit/gnulib.git/commit/lib/malloca.c?id=ef5a4088d9236a55283d1eb576f560aa39c09e6f. If the toolchain doesn't provide the header, gnulib provides a fallback version of its own: https://git.savannah.gnu.org/cgit/gnulib.git/tree/lib/stdckdint.in.h

Now since Clang provides it since this commit, gnulib doesn't provide their own fallback, but goes on to use `ckd_add`. This fails with Clang's `<stdckdint.h>` implementation, since gnulib isn't built in C23 mode but still wants to use `<stdckdint.h>`:

  i686-w64-mingw32-clang -DHAVE_CONFIG_H -DEXEEXT=\".exe\" -I. -I../../../gettext-runtime/gnulib-lib -I..  -I../intl -I../../../gettext-runtime/intl -DDEPENDS_ON_LIBICONV=1 -DDEPENDS_ON_LIBINTL=1 -I/home/martin/fate/vlc/src/contrib/i686-w64-mingw32/include  -Wno-cast-qual -Wno-conversion -Wno-float-equal -Wno-sign-compare -Wno-undef -Wno-unused-function -Wno-unused-parameter -Wno-float-conversion -Wimplicit-fallthrough -Wno-pedantic -Wno-sign-conversion -Wno-type-limits -I/home/martin/fate/vlc/src/contrib/i686-w64-mingw32/include -g -O2 -c -o libgrt_a-malloca.o `test -f 'malloca.c' || echo '../../../gettext-runtime/gnulib-lib/'`malloca.c
  ../../../gettext-runtime/gnulib-lib/malloca.c:53:8: error: call to undeclared function 'ckd_add'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     53 |   if (!ckd_add (&nplus, n, plus) && !xalloc_oversized (nplus, 1))
        |        ^
  1 error generated.
  make: *** [Makefile:2246: libgrt_a-malloca.o] Error 1

It seems like GCC's version of this header exposes the functionality even if compiled in an older language mode: https://github.com/gcc-mirror/gcc/blob/f019251ac9be017aaf3c58f87f43d88b974d21cf/gcc/ginclude/stdckdint.h

Would you consider changing the Clang version to do the same? Otherwise we would need to convince gnulib to not try to use/polyfill this header unless gnulib itself is compiled in C23 mode.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157331/new/

https://reviews.llvm.org/D157331