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
