Re: [XEN PATCH 1/4] build: xen/include: use if_changed

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Anthony,

> On 9 Jun 2022, at 13:55, Anthony PERARD <anthony.perard@xxxxxxxxxx> wrote:
> 
> On Thu, Jun 09, 2022 at 11:51:20AM +0000, Bertrand Marquis wrote:
>> Hi,
>> 
>>> On 9 Jun 2022, at 11:26, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>> 
>>> On 09.06.2022 12:16, Bertrand Marquis wrote:
>>>> With this change, compiling for x86 is now ending up in:
>>>> CHK     include/headers99.chk
>>>> make[9]: execvp: /bin/sh: Argument list too long
>>>> make[9]: *** [include/Makefile:181: include/headers++.chk] Error 127
>>>> 
>>>> Not quite sure yet why but I wanted to signal it early as other might be 
>>>> impacted.
>>>> 
>>>> Arm and arm64 builds are not impacted.
>>> 
>>> Hmm, that patch has passed the smoke push gate already, so there likely is
>>> more to it than there being an unconditional issue. I did build-test this
>>> before pushing, and I've just re-tested on a 2nd system without seeing an
>>> issue.
>> 
>> I have the problem only when building using Yocto, I did a normal build and 
>> the
>> issue is not coming.
>> 
> 
> Will the following patch help?
> 
> 
> From 0f32f749304b233c0d5574dc6b14f66e8709feba Mon Sep 17 00:00:00 2001
> From: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> Date: Thu, 9 Jun 2022 13:42:52 +0100
> Subject: [XEN PATCH] build,include: rework shell script for headers++.chk
> 
> The command line generated for headers++.chk by make is quite long,
> and in some environment it is too long. This issue have been seen in
> Yocto build environment.
> 
> Error messages:
>    make[9]: execvp: /bin/sh: Argument list too long
>    make[9]: *** [include/Makefile:181: include/headers++.chk] Error 127
> 
> Rework to that we do the foreach loop in shell rather that make to
> reduce the command line size by a lot. We also need a way to get
> headers prerequisite for some public headers so we use a switch "case"
> in shell to be able to do some simple pattern matching. Variables
> alone in POSIX shell don't allow to work with associative array or
> variables with "/".
> 
> Reported-by: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
> Fixes: 28e13c7f43 ("build: xen/include: use if_changed")
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> ---
> xen/include/Makefile | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/include/Makefile b/xen/include/Makefile
> index 6d9bcc19b0..ca5e868f38 100644
> --- a/xen/include/Makefile
> +++ b/xen/include/Makefile
> @@ -158,13 +158,22 @@ define cmd_headerscxx_chk
>           touch $@.new;                                                     \
>           exit 0;                                                           \
>       fi;                                                                   \
> -     $(foreach i, $(filter %.h,$^),                                        \
> -         echo "#include "\"$(i)\"                                          \
> +     get_prereq() {                                                        \
> +         case $$1 in                                                       \
> +         $(foreach i, $(filter %.h,$^),                                    \
> +         $(if $($(patsubst $(srctree)/%,%,$i)-prereq),                     \
> +             $(patsubst $(srctree)/%,%,$i)$(close)                         \
> +             echo "$(foreach j, $($(patsubst $(srctree)/%,%,$i)-prereq),   \
> +                     -include c$(j))";;))                                  \
> +         esac;                                                             \
> +     };                                                                    \
> +     for i in $(filter %.h,$^); do                                         \
> +         echo "#include "\"$$i\"                                           \
>           | $(CXX) -x c++ -std=gnu++98 -Wall -Werror -D__XEN_TOOLS__        \
>             -include stdint.h -include $(srcdir)/public/xen.h               \
> -           $(foreach j, $($(patsubst $(srctree)/%,%,$i)-prereq), -include 
> c$(j)) \
> +           `get_prereq $$i`                                                \
>             -S -o /dev/null -                                               \
> -         || exit $$?; echo $(i) >> $@.new;) \
> +         || exit $$?; echo $$i >> $@.new; done;                            \
>       mv $@.new $@
> endef
> 

Just a small reminder that you need to push this patch officially :-)

Cheers
Bertrand