Hi Sam, 2017-04-04 5:20 GMT+09:00 Sam Ravnborg <sam@xxxxxxxxxxxx>: > On Mon, Apr 03, 2017 at 03:25:10PM +0200, Michal Marek wrote: >> On 2017-04-03 09:42, Masahiro Yamada wrote: >> > Each Makefile knows it wants to see >> > additional headers in the source tree, or objtree. >> > >> > I am guessing the right approach in a long run is, >> > we require -I to specify $(srctree) or $(objtree) explicitly. >> > >> > ccflags-y := -I$(srctree)/foo/bar/baz >> > >> > or >> > >> > ccflags-y := -I$(objtree)/foo/bar/baz >> > >> > >> > (For the latter, we can omit $(objtree)/ as it is ./) >> > >> > >> > Then, delete $(call flags,_c_flags) after the conversion. >> >> Agreed. The addtree function is more of a hack to make things just work >> with O=, but AFAIK there is no clean way to implement VPATH for -I >> arguments. So it's sensible to get rid of the hack. It looks like it's >> going to be lot of work though: >> >> $ git grep -e '-I' -- '*Makefile*' | wc -l >> 732 >> $ git grep -e '-I *\$(\(src\|obj\)tree)' -- '*Makefile*' | wc -l >> 166 > > There was a goal long time ago that moving the kernel source should > not trigger a rebuild. > Any hardcoded path would violate this (like $(srctree), $(objtree)) Even if we avoid hard-coding $(srctree) in each Makefile, "addtree" will modify the -I paths and the modified paths will be recorded in .*.cmd files. If we really want to achieve the goal, my old patch seemed to have a point: https://patchwork.kernel.org/patch/4511991/ This was rejected due to side effects, anyway. -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
