It looks like GCC recently moved from 'char *' to 'void *'. This SO question[1] (4 years ago) quotes the GCC docs and they had 'char *'. Maybe Clang hasn't noticed the change. I'll report a bug. [1]: https://stackoverflow.com/q/35741814/6872717 On 12/9/20 8:15 PM, Alejandro Colomar (man-pages) wrote: > Hi Heinrich, > > It looks like a bug (or at least an undocumented divergence from GCC) in > Clang/LLVM. Or I couldn't find the documentation for it. > > Clang uses 'char *': > https://github.com/llvm/llvm-project/blob/7faf62a80bfc3a9dfe34133681fcc31f8e8d658b/clang/include/clang/Basic/Builtins.def#L583 > > GCC uses 'void *': > https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html > > I CCd Clang and GCC lists; maybe they know about that divergence. > > Cheers, > > Alex > > On 12/9/20 7:48 PM, Heinrich Schuchardt wrote: >> On 12/9/20 7:34 PM, Alejandro Colomar (man-pages) wrote: >>> Hi Heinrich & Michael, >>> >>> What about the following?: >>> >>> [ >>> NOTES >>> GCC provides a similar function, which may be useful on archi‐ >>> tectures that lack this system call: >>> >>> void __builtin___clear_cache(void *begin, void *end); >>> ] >> >> I just checked building with Clang/LLVM. There the arguments are of type >> (char *). See the following error output: >> >> +arch/sandbox/cpu/cache.c:19:26: error: passing 'uint8_t *' (aka >> 'unsigned char *') to parameter of type 'char *' converts between >> pointers to integer types with different sign [-Werror,-Wpointer-sign] >> + __builtin___clear_cache(state->ram_buf, >> + ^~~~~~~~~~~~~~ >> +arch/sandbox/cpu/cache.c:20:12: error: passing 'uint8_t *' (aka >> 'unsigned char *') to parameter of type 'char *' converts between >> pointers to integer types with different sign [-Werror,-Wpointer-sign] >> + state->ram_buf + state->ram_size); >> + ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> Best regards >> >> Heinrich >> >>> >>> Cheers, >>> >>> Alex >>> >>> On 12/9/20 7:04 PM, Heinrich Schuchardt wrote: >>>> Hello Michael, >>>> >>>> function cacheflush() does not exist on many architectures. >>>> >>>> It would have saved me a lot of time if the man-page had referenced >>>> GCC's >>>> >>>> void __builtin___clear_cache(void *begin, void *end) >>>> >>>> Maybe you can add it to NOTES. >>>> >>>> Best regards >>>> >>>> heirnich >>> >> > -- Alejandro Colomar Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es
