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kbuild: rename cmd_$@ to savedcmd_$@ in *.cmd files

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The cmd-check macro compares $(cmd_$@) and $(cmd_$1), but a pitfall is
that you cannot use cmd_<target> as the variable name for the command.

For example, the following code will not work in the top Makefile
or ./Kbuild.

    quiet_cmd_foo = GEN     $@
          cmd_foo = touch $@

    targets += foo
    foo: FORCE
            $(call if_changed,foo)

In this case, both $@ and $1 are expanded to 'foo', so $(cmd_check)
is always empty.

We do not need to use the same prefix for cmd_$@ and cmd_$1.
Rename the former to savedcmd_$@.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
This commit is contained in:
Masahiro Yamada
2022-12-29 18:15:00 +09:00
parent 91ecf7ff1b
commit 92215e7a80
4 changed files with 8 additions and 8 deletions
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8
scripts/Kbuild.include
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@@ -170,10 +170,10 @@ cmd = @$(if $(cmd_$(1)),set -e; $($(quiet)log_print) $(delete-on-interrupt) $(cm
ifneq ($(KBUILD_NOCMDDEP),1)
# Check if both commands are the same including their order. Result is empty
# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(savedcmd_$@))), \
$(subst $(space),$(space_escape),$(strip $(cmd_$1))))
else
cmd-check = $(if $(strip $(cmd_$@)),,1)
cmd-check = $(if $(strip $(savedcmd_$@)),,1)
endif
# Replace >$< with >$$< to preserve $ when reloading the .cmd file
@@ -199,7 +199,7 @@ if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:)
cmd_and_savecmd = \
$(cmd); \
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd
printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd
# Execute the command and also postprocess generated .d dependencies file.
if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
@@ -239,7 +239,7 @@ _why = \
$(if $(wildcard $@), \
$(if $(newer-prereqs),- due to: $(newer-prereqs), \
$(if $(cmd-check), \
$(if $(cmd_$@),- due to command line change, \
$(if $(savedcmd_$@),- due to command line change, \
$(if $(filter $@, $(targets)), \
- due to missing .cmd file, \
- due to $(notdir $@) not in $$(targets) \