Re: [Minios-devel] Add "-nostdinc" to gcc when HAVE_LIBC is not enabled

[Huang Shijie <shijie.huang@xxxxxxx>]

On Wed, Dec 13, 2017 at 09:34:15AM +0100, Samuel Thibault wrote:
> Huang Shijie, on mer. 13 déc. 2017 03:26:12 +0000, wrote:
> > On Tue, Dec 12, 2017 at 10:55:31AM +0100, Samuel Thibault wrote:
> > > Huang Shijie, on mar. 12 déc. 2017 09:50:20 +0000, wrote:
> > > >     I am trying to add the DTC to the mini-os by coping its code to 
> > > > minios.
> > > >
> > > >     I added the "-nostdinc" to gcc when the HAVE_LIBC
> > > >     is not enabled, and I copied the headers from the FreeBSD code.
> > > >
> > > >     (Of course, I copied many headers from the FreeBSD code, such as 
> > > > stddef.h, stdarg.h..)
> > > >
> > > >     It is a big patch for the mini-os. So is this a good idea, or a bad 
> > > > idea?
> > >
> > > These should be provided by the compiler, not libc. You need to add the
> > > compiler header search path along -nostdinc.
> > okay.
> > But the gcc compiler header is GPL v2,
>
> I'm not saying to copy the gcc headers, but just add the search path
> with -I.

I have dropped the "-nostdinc" option now, the following is what I did:

  1.) Use a patch to copy the libfdt to mini-os.

        ---
         Makefile                     |   15 +
         lib/libfdt/Makefile.libfdt   |   11 +
         lib/libfdt/TODO              |    3 +
         lib/libfdt/fdt.c             |  251 ++++++
         lib/libfdt/fdt.h             |  111 +++
         lib/libfdt/fdt_addresses.c   |   96 +++
         lib/libfdt/fdt_empty_tree.c  |   83 ++
         lib/libfdt/fdt_overlay.c     |  861 +++++++++++++++++++
         lib/libfdt/fdt_ro.c          |  703 ++++++++++++++++
         lib/libfdt/fdt_rw.c          |  505 +++++++++++
         lib/libfdt/fdt_strerror.c    |  102 +++
         lib/libfdt/fdt_sw.c          |  300 +++++++
         lib/libfdt/fdt_wip.c         |  139 ++++
         lib/libfdt/libfdt.h          | 1899 
++++++++++++++++++++++++++++++++++++++++++
         lib/libfdt/libfdt_env.h      |  139 ++++
         lib/libfdt/libfdt_internal.h |   95 +++
         lib/libfdt/version.lds       |   71 ++
        ---

  2.) Use a patch to fix the build issue for libfdt.
      The patch is like this:

       ------------------------- patch begin -----------------------------------
        We will meet the compilor error when the HAVE_LIBC is not enabled:
          --------------------------------------------------------------------
        In file included from /usr/include/aarch64-linux-gnu/sys/select.h:45:0,
                         from /usr/include/aarch64-linux-gnu/sys/types.h:219,
                         from /usr/include/stdlib.h:314,
                         from lib/libfdt/libfdt_env.h:57,
                         from lib/libfdt/fdt.c:51:
        /usr/include/aarch64-linux-gnu/bits/time.h:30:8: error: redefinition of 
‘struct timeval’
         struct timeval
                ^
        In file included from /root/mini-os/include/time.h:49:0,
                         from /usr/include/aarch64-linux-gnu/sys/types.h:132,
                         from /usr/include/stdlib.h:314,
                         from lib/libfdt/libfdt_env.h:57,
                         from lib/libfdt/fdt.c:51:
        /root/mini-os/include/sys/time.h:35:8: note: originally defined here
         struct timeval {
                ^
        minios.mk:68: recipe for target '/root/mini-os/lib/libfdt/fdt.o' failed
        make: *** [/root/mini-os/lib/libfdt/fdt.o] Error 1
          --------------------------------------------------------------------

        This patch changes the libfdt_env.h, and fix the compiler error.

        Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx>
        ---
         lib/libfdt/libfdt_env.h | 4 ++++
         1 file changed, 4 insertions(+)

        diff --git a/lib/libfdt/libfdt_env.h b/lib/libfdt/libfdt_env.h
        index bd24746..a78d01f 100644
        --- a/lib/libfdt/libfdt_env.h
        +++ b/lib/libfdt/libfdt_env.h
        @@ -54,7 +54,11 @@

         #include <stddef.h>
         #include <stdint.h>
        +
        +#ifdef HAVE_LIBC
         #include <stdlib.h>
        +#endif
        +
         #include <string.h>

         #ifdef __CHECKER__
        --
       ------------------------- patch end  -----------------------------------

 If there is any issue, please tell me. Thanks.

Thanks
Huang Shijie
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