[xen staging] build,include: rework shell script for headers++.chk

[patchbot@xxxxxxx]

commit 61ac7919a6a38a24d26fd1b57a2511beb0724e99
Author:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
AuthorDate: Thu Jun 23 09:40:12 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jun 23 09:40:12 2022 +0200

    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 so 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 "/".
    
    Also rework headers99.chk as it has a similar implementation, even if
    with only two headers to check the command line isn't too long at the
    moment.
    
    Fixes: 28e13c7f43 ("build: xen/include: use if_changed")
    Reported-by: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
    Tested-by: Michal Orzel <michal.orzel@xxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/include/Makefile | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/xen/include/Makefile b/xen/include/Makefile
index 617599df7e..510f65c92a 100644
--- a/xen/include/Makefile
+++ b/xen/include/Makefile
@@ -141,13 +141,24 @@ cmd_header_chk = \
 quiet_cmd_headers99_chk = CHK     $@
 define cmd_headers99_chk
        rm -f $@.new; \
-       $(foreach i, $(filter %.h,$^),                                        \
-           echo "#include "\"$(i)\"                                          \
+       get_prereq() {                                                        \
+           case $$1 in                                                       \
+           $(foreach i, $(filter %.h,$^),                                    \
+           $(if $($(patsubst $(srctree)/%,%,$(i))-prereq),                   \
+               $(i)$(close)                                                  \
+               echo "$(foreach j, $($(patsubst $(srctree)/%,%,$(i))-prereq), \
+                       -include $(j).h)";;))                                 \
+           *) ;;                                                             \
+           esac;                                                             \
+       };                                                                    \
+       for i in $(filter %.h,$^); do                                         \
+           echo "#include "\"$$i\"                                           \
            | $(CC) -x c -std=c99 -Wall -Werror                               \
              -include stdint.h                                               \
-             $(foreach j, $($(patsubst $(srctree)/%,%,$i)-prereq), -include 
$(j).h) \
+             $$(get_prereq $$i)                                              \
              -S -o /dev/null -                                               \
-           || exit $$?; echo $(i) >> $@.new;) \
+           || exit $$?; echo $$i >> $@.new;                                  \
+       done;                                                                 \
        mv $@.new $@
 endef
 
@@ -158,13 +169,23 @@ define cmd_headerscxx_chk
            touch $@.new;                                                     \
            exit 0;                                                           \
        fi;                                                                   \
-       $(foreach i, $(filter %.h,$^),                                        \
-           echo "#include "\"$(i)\"                                          \
+       get_prereq() {                                                        \
+           case $$1 in                                                       \
+           $(foreach i, $(filter %.h,$^),                                    \
+           $(if $($(patsubst $(srctree)/%,%,$(i))-prereq),                   \
+               $(i)$(close)                                                  \
+               echo "$(foreach j, $($(patsubst $(srctree)/%,%,$(i))-prereq), \
+                       -include c$(j))";;))                                  \
+           *) ;;                                                             \
+           esac;                                                             \
+       };                                                                    \
+       for i in $(filter %.h,$^); do                                         \
+           echo "#include "\"$$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
 
--
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