[PATCH v10 03/13] kbuild: add tristate checker

@@ -52,6 +52,7 @@
 *.zst
 Module.symvers
 modules.order
+check-tristates.objs
 
 #
 # Top-level generic files

@@ -183,6 +183,7 @@ modules.builtin
 modules.builtin.*
 modules.nsdeps
 modules.order
+check-tristates.objs
 modversions.h*
 nconf
 nconf-cfg

@@ -1689,6 +1689,7 @@ help:
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  '  clang-analyzer  - Check with clang static analyzer'
 	@echo  '  clang-tidy      - Check with clang-tidy'
+	@echo  '  tristatecheck   - Check for non-tristates with MODULE_ declarations'
 	@echo  ''
 	@echo  'Tools:'
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'

@@ -2012,7 +2013,7 @@ clean: $(clean-dirs)
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
 		-o -name '*.symtypes' -o -name 'modules.order' \
-		-o -name '.tmp_*' \
+		-o -name 'check-tristates.objs' -o -name '.tmp_*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
 		-o -name '*.gcno' \

@@ -2082,7 +2083,25 @@ coccicheck:
 export_report:
 	$(PERL) $(srctree)/scripts/export_report.pl
 
-PHONY += checkstack kernelrelease kernelversion image_name
+tristatecheck: SHELL=/bin/bash
+tristatecheck: check-tristates.objs modules.builtin.objs
+	$(Q) for name in $$(comm -23 <(sed 's,:,,' modules.builtin.objs | tr ' ' '\n' | sort -u) \
+				    <(sed 's,:,,' check-tristates.objs | tr ' ' '\n' | sort -u)); do \
+		grep -w $$name modules.builtin.objs | while read -r line; do \
+			case $$line in \
+			$$name:\ ) printf "%s " "$$line" | sed 's,: ,,';; \
+			$$name:\ *) printf "%s " "$$line" | sed 's,^.*: ,,';; \
+			*) echo $$name;; \
+			esac; \
+		done; \
+	     done | tr ' ' '\n' | sort -u | while read -r name; do \
+		test -f $${name%.o}.c && echo $${name%.o}.c; \
+	     done | xargs grep -l '^ *MODULE_' || true
+
+check-tristates.objs: $(build-dir)
+	$(Q)$(MAKE) $(tristatecheck)=$^ tristates-file=$@
+
+PHONY += checkstack kernelrelease kernelversion image_name tristatecheck
 
 # UML needs a little special treatment here.  It wants to use the host
 # toolchain, so needs $(SUBARCH) passed to checkstack.pl.  Everyone

@@ -78,6 +78,12 @@ endef
 # $(Q)$(MAKE) $(build)=dir
 build := -f $(srctree)/scripts/Makefile.build obj
 
+###
+# Shorthand for $(Q)$(MAKE) -f scripts/check-tristates.mk need-tristates=1 obj=
+# Usage:
+# $(Q)$(MAKE) $(tristatecheck)=dir
+tristatecheck := -f $(srctree)/scripts/check-tristates.mk need-tristates=1 obj
+
 ###
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
 # Usage:

@@ -39,11 +39,17 @@ else
 obj-m := $(filter-out %/, $(obj-m))
 endif
 
-ifdef need-builtin
+ifdef need-tristates
+subdir-ym	:= $(sort $(subdir-y) $(subdir-m) \
+			$(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m) $(obj-Y) $(obj-M))))
 obj-y		:= $(patsubst %/, %/built-in.a, $(obj-y))
 else
+ifdef need-builtin
+obj-y          := $(patsubst %/, %/built-in.a, $(obj-y))
+else
 obj-y		:= $(filter-out %/, $(obj-y))
 endif
+endif
 
 # Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
 suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))

@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+# ==========================================================================
+# Generating check-tristates.objs
+# ==========================================================================
+
+src := $(obj)
+
+PHONY := __tristates
+__tristates:
+
+include include/config/auto.conf
+# tristate.conf sets tristate variables to uppercase 'Y' or 'M'
+# That way, we get the list of built-in modules in obj-Y
+include include/config/tristate.conf
+
+include scripts/Kbuild.include
+
+ifdef building_out_of_srctree
+# Create output directory if not already present
+_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
+endif
+
+# The filename Kbuild has precedence over Makefile
+kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
+kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
+include $(kbuild-file)
+
+include scripts/Makefile.lib
+
+check-tristates-subdirs := $(patsubst %,%/check-tristates.objs, $(subdir-ym))
+check-tristates-target  := $(obj)/check-tristates.objs
+
+__tristates: $(obj)/$(tristates-file) $(subdir-ym)
+	@:
+
+$(check-tristates-target): $(subdir-ym) FORCE
+	$(Q) rm -f $@
+	$(Q) $(foreach mod-o, $(filter %.o,$(obj-Y)),\
+		printf "%s: " $(addprefix $(obj)/,$(mod-o)) >> $@; \
+		printf " %s" $(sort $(strip $(addprefix $(obj)/,$($(mod-o:.o=-objs)) \
+			$($(mod-o:.o=-y)) $($(mod-o:.o=-Y))))) >> $@; \
+		printf "\n" >> $@; ) \
+	cat /dev/null $(check-tristates-subdirs) >> $@;
+
+PHONY += FORCE
+
+FORCE:
+
+# Descending
+# ---------------------------------------------------------------------------
+
+PHONY += $(subdir-ym)
+$(subdir-ym):
+	$(Q)$(MAKE) $(tristatecheck)=$@ tristates-file=$(tristates-file)
+
+.PHONY: $(PHONY)