Hi Jani > Sometimes it's useful to be able to explicitly ensure certain headers > remain self-contained, i.e. that they are compilable as standalone > units, by including and/or forward declaring everything they depend on. > > Add special target header-test-y where individual Makefiles can add > headers to be tested if CONFIG_HEADER_TEST is enabled. This will > generate a dummy C file per header that gets built as part of extra-y. Very useful, thanks. I have cooked up something ad-hoc a couple of times but having it as a standard feature in the build system is much better. The we can let some of our infrastructure pick up an issues automatically. > > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > Cc: Michal Marek <michal.lkml@xxxxxxxxxxx> > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> > --- > Documentation/kbuild/makefiles.txt | 7 +++++++ > init/Kconfig | 9 +++++++++ > scripts/Makefile.build | 10 ++++++++++ > scripts/Makefile.lib | 3 +++ > 4 files changed, 29 insertions(+) > > diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt > index 03c065855eaf..73df58e5ea0c 100644 > --- a/Documentation/kbuild/makefiles.txt > +++ b/Documentation/kbuild/makefiles.txt > @@ -1036,6 +1036,13 @@ When kbuild executes, the following steps are followed (roughly): > In this example, extra-y is used to list object files that > shall be built, but shall not be linked as part of built-in.a. > > + header-test-y > + > + header-test-y specifies headers (*.h) in the current directory that > + should be compile tested to ensure they are self-contained, > + i.e. compilable as standalone units. If CONFIG_HEADER_TEST is enabled, > + this autogenerates dummy sources to include the headers, and builds them > + as part of extra-y. Do we want to restrict this to current directory only? Sometimes we could use this for headers in include/ but let it trigger for the relevant subsystem. So for example drivers/gpu/drm/Makefile will include the rules for all headers in include/drm/* The alternative would be Makefiles (of Kbuild files) scattered in the directories with headers and then some infrastructure to visit those. Follow patch extend the header-test feature to work with headers in include/ Example: # Header files from this directory header-test-y += drm_crtc_helper_internal.h header-test-y += drm_crtc_internal.h .. . # Header files from include/drm header-test-y += drm/amd_asic_type.h header-test-y += drm/ati_pcigart.h ... In the patch $* is used to get the "stem" from the pattern. This is the filname of the header file without extension. Sam diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 4d4bf698467a..ca132ab3a551 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -295,11 +295,10 @@ $(obj)/%.lst: $(src)/%.c FORCE # --------------------------------------------------------------------------- quiet_cmd_header_test = HDRTEST $@ - cmd_header_test = echo "\#include \"$(<F)\"" > $@ + cmd_header_test = echo "\#include <$(2).h>" > $@ -# FIXME: would be nice to be able to limit this implicit rule to header-test-y -$(obj)/%.header_test.c: $(src)/%.h FORCE - $(call if_changed,header_test) +$(obj)/%.header_test.c: + $(call cmd,header_test,$*) # Compile assembler sources (.S) # ---------------------------------------------------------------------------
