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

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

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
 



-- 
Anthony PERARD