Hello Martin, Thanks for the correction! Then the prototypes that changes from 'char *' to 'void *' in r269082 were not exposed to the user, right? I guess then those are just internal implementation where GCC did use 'char *'. Where is the actual prototype exposed to the user declared? Thanks, Alex P.S.: Michael, wait for a patch revision (v6). On 12/14/20 10:13 PM, Martin Sebor wrote: > On 12/11/20 11:14 AM, Alejandro Colomar (man-pages) via Gcc wrote: >> 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 *'. > > __builtin___clear_cache in GCC has always been declared to take > void*. The signature in the manual was recently corrected to match > the implementation, i.e., from char* to void*, in r269082. > > Martin > >> 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
