[U-Boot] [RFC] Proposal to change include search model

[Jeroen Hofstee <dasuboot@myspectrum.nl>]

On di, 2014-06-10 at 18:53 +0300, Vasili Galka wrote:
> Hi,
> 
> Currently U-Boot has a long list of include search paths. This makes
> it hard to understand the location of each header. Moreover, it opens
> an easy opportunity for breaking build by including the wrong header.
> This is especially easy when compiling the tools directory. I found
> numerous commits dealing with such problems over the years.
> 
> What I propose is changing the way of how #include directives are
> written. For example instead of:
> 
> #include <stdlib.h>             /* From toolchain */
> #include <api_public.h>         /* include/api_public.h */
> #include <linux/mii.h>          /* include/linux/mii.h */
> #include <config.h>             /* Auto-generated somewhere */
> #include <bmp_logo.h>           /* Auto-generated somewhere */
> #include <asm/arcregs.h>        /* arch/arc/include/asm/arcregs.h */
> #include <asm/arch/emac_defs.h> /* arch/arm/include/asm/
>                                      arch-davinci/emac_defs.h */
> #include "../../../../../drivers/net/davinci_emac.h"
> 
> and let the developer guess the locations... I propose writing:
> 
> #include <stdlib.h>             /* <> means from toolchain */
> #include "inc/api_public.h"     /* From u-boot/include/ dir */
> #include "inc/linux/mii.h"
> #include "config/config.h"      /* From dedicated config dir */
> #include "generated/bmp_logo.h"
> #include "arch/asm/arcregs.h"   /* From configured architecture */
> #include "soc/emac_defs.h"      /* From configured SoC */
> #include "u-boot/drivers/net/davinci_emac.h"
> 
> This way the developer will instantly know the exact header locations.
> Moreover, the chance for ambiguities is very small which makes build
> breakages less likely.
> 
> The proposal may seem strange to you at first, as most of you are
> probably used to a different approach. But please consider its
> advantages. I've been working on projects that used similar scheme
> and it significantly simplifies the developer life.
> 
> The above can be implemented by creating
> inc/ arch/ soc/ u-boot/
> filesystem links in ${objtree}/include. Then, the only compiler flag
> required will be "-iquote ${objtree}/include". No ugly -idirafter flags,
> no long search list. Keep it simple.
> 
> I'll be glad for your opinions!
> 
This sounds way too complex if you ask me for what your are trying to
fix. For one thing #include<> versus include "" is compiler specific and
not defined in general. If I find some time I will see if I can find
another solution for it. But you're warned heads up that it might
include one additional -I for standard c libraries for the target (which
is only errno.h at the moment, afaik) ;)

Regards,
Jeroen