[1/2] kbuild: rename cmd_$@ to savedcmd_$@ in *.cmd files
Commit Message
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>
---
scripts/Kbuild.include | 8 ++++----
scripts/Makefile.modfinal | 2 +-
scripts/basic/fixdep.c | 4 ++--
scripts/clang-tools/gen_compile_commands.py | 2 +-
4 files changed, 8 insertions(+), 8 deletions(-)
Comments
On Thu, Dec 29, 2022 at 06:15:00PM +0900 Masahiro Yamada wrote:
> 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>
> ---
>
> scripts/Kbuild.include | 8 ++++----
> scripts/Makefile.modfinal | 2 +-
> scripts/basic/fixdep.c | 4 ++--
> scripts/clang-tools/gen_compile_commands.py | 2 +-
> 4 files changed, 8 insertions(+), 8 deletions(-)
>
Thanks for fixing this, I wasn't aware of that at all.
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
@@ -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) \
@@ -54,7 +54,7 @@ newer_prereqs_except = $(filter-out $(PHONY) $(1),$?)
# Same as if_changed, but allows to exclude specified extra dependencies
if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \
$(cmd); \
- printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
+ printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
# Re-generate module BTFs if either module's .ko or vmlinux changed
%.ko: %.o %.mod.o scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),vmlinux) FORCE
@@ -70,7 +70,7 @@
*
* It first generates a line
*
- * cmd_<target> = <cmdline>
+ * savedcmd_<target> = <cmdline>
*
* and then basically copies the .<target>.d file to stdout, in the
* process filtering out the dependency on autoconf.h and adding
@@ -344,7 +344,7 @@ int main(int argc, char *argv[])
target = argv[2];
cmdline = argv[3];
- printf("cmd_%s := %s\n\n", target, cmdline);
+ printf("savedcmd_%s := %s\n\n", target, cmdline);
buf = read_file(depfile);
parse_dep_file(buf, target);
@@ -19,7 +19,7 @@ _DEFAULT_OUTPUT = 'compile_commands.json'
_DEFAULT_LOG_LEVEL = 'WARNING'
_FILENAME_PATTERN = r'^\..*\.cmd$'
-_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c) *(;|$)'
+_LINE_PATTERN = r'^savedcmd_[^ ]*\.o := (.* )([^ ]*\.c) *(;|$)'
_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
# The tools/ directory adopts a different build system, and produces .cmd
# files in a different format. Do not support it.