Hello, Ahmad, On Mon, Apr 19, 2021 at 09:58:06AM +0200, Ahmad Fatoum wrote: > Hello Peter, > > On 7/8/20 11:02 PM, Peter Mamonov wrote: > >>> I tried to build MicroPython using barebox toolchain and found a number of > >>> conflicts between barebox and compiler headers. Below you will find the patch > >>> which demostrates some of them. In this particular example the problem arises > >>> due to simultaneous inclusion of some compiler headers along with barebox > >>> version of `strings.h`, which in turn includes barebox analogs of those headers > >>> from `include/linux`. I belive there should be a segregation between headers in > >>> `include` and in `include/linux`, i.e. headers from `include/` should not > >>> reference <linux/*.h> headers. Yet I understand this is somewhat problematic. > >>> What do you think? > >> > >> barebox code shouldn't make use of any compiler headers at all, except for <stdarg.h>. > >> The only exception are arch/sandbox/os and scripts/, which reference libc headers. > >> Everything else should comes out of barebox' include/ directory. > >> > >> If you have foreign code that you want to port into barebox, either modify it > >> to use barebox headers or change the include order when building it to use _local_ > >> versions of the headers it requires. > > > > Ok, I've got your point. Yet I want to point out that addition of *unmodified* > > code in a form of git submodule would greatly simplify further support of this > > port. Unfortunately modifying include order will not help in this case, since, > > for example, both `barebox/include/linux/stddef.h` (included from > > `barebox/include/string.h` via <linux/string.h>, etc.) and > > `/usr/lib/gcc-cross/<ARCH>-linux-gnu/X/include/stdbool.h` define `true`/`false` > > macros. On the other hand `/usr/include/linux/stddef.h` and > > `/usr/lib/gcc/<ARCH>-linux-gnu/X/include/stdbool.h` coexist in GNU/Linux system > > nicely, since no header from `/usr/include/` does reference <linux/*.h> > > headers. > > Even if our headers didn't clash, our symbols might. You want to use the > same declaration/prototype everywhere a symbol is used. > > If you have external code that uses, say, <string.h>. You write your own string.h, > and ensure it's first in include path for all the code in the HAL (or w/e) directory > you have. In that file you could have your wrappers and then #include_next <stdio.h> > if needed. > > If you have global symbols clashing in incompatible ways, you could perhaps > postprocess the micropython object code with objcopy to give all symbols a > micropython_ prefix..? > > The proper abstraction is probably to have a module, but that seems only supported > on ARM. > > >>> diff --git a/commands/types_conflict.c b/commands/types_conflict.c > >>> new file mode 100644 > >>> index 0000000000..70fee8d6f4 > >>> --- /dev/null > >>> +++ b/commands/types_conflict.c > >>> @@ -0,0 +1,12 @@ > >>> +#include <stdbool.h> > >>> +#include <stdint.h> > >>> +#include <stddef.h> > >>> + > >>> +#include <string.h> > >> > >> barebox (except sandbox) is meant to be compiled with freestanding C implementations > >> that aren't required to provide a <string.h>. So no barebox code should depend on > >> compiler-provided <string.h>. > > > > Actually `string.h` comes from barebox's `include/` dir, while `std*.h` come > > from compiler's include dir. > > > > > > PS: By the way, do you think Barebox will benefit from importing MicroPython > > (https://micropython.org/) and exposing some of Barebox APIs to it? > > We have setjmp/longjmp on all architectures now, so it should make porting MicroPython > easier. I probably wouldn't use it, but I guess it could have some educational value > for people interested to go from MicroPython + Microcontroller to an > application processor..? > > It'd be cool to have for sure ;) Looks like it requires considerable amount of effort, yet no obvious benefit for the community is to be achieved, so I opt to abandon it. Regards, Peter > > Cheers, > Ahmad > > > Regards, > > Peter > > -- > Pengutronix e.K. | | > Steuerwalder Str. 21 | http://www.pengutronix.de/ | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
