kbuild: add support for ensuring headers are self-contained

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.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Jani Nikula 2019-06-04 15:42:48 +03:00 committed by Masahiro Yamada
parent 0315bb7a25
commit e846f0dc57
9 changed files with 32 additions and 12 deletions

1
.gitignore vendored
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@ -22,6 +22,7 @@
*.elf
*.gcno
*.gz
*.hdrtest.c
*.i
*.ko
*.lex.c

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@ -19,6 +19,7 @@
*.grep
*.grp
*.gz
*.hdrtest.c
*.html
*.i
*.jpeg

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@ -1018,6 +1018,13 @@ 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.
--- 6.7 Commands useful for building a boot image

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@ -1647,6 +1647,7 @@ clean: $(clean-dirs)
-o -name '*.dwo' -o -name '*.lst' \
-o -name '*.su' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-o -name '*.hdrtest.c' \
-o -name '*.lex.c' -o -name '*.tab.[ch]' \
-o -name '*.asn1.[ch]' \
-o -name '*.symtypes' -o -name 'modules.order' \

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@ -1 +0,0 @@
header_test_*.c

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@ -2,7 +2,7 @@
# Copyright © 2019 Intel Corporation
# Test the headers are compilable as standalone units
header_test := \
header-test-$(CONFIG_DRM_I915_WERROR) := \
i915_active_types.h \
i915_gem_context_types.h \
i915_priolist_types.h \
@ -35,13 +35,3 @@ header_test := \
intel_sprite.h \
intel_tv.h \
intel_workarounds_types.h
quiet_cmd_header_test = HDRTEST $@
cmd_header_test = echo "\#include \"$(<F)\"" > $@
header_test_%.c: %.h
$(call cmd,header_test)
i915-$(CONFIG_DRM_I915_WERROR) += $(foreach h,$(header_test),$(patsubst %.h,header_test_%.o,$(h)))
clean-files += $(foreach h,$(header_test),$(patsubst %.h,header_test_%.c,$(h)))

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@ -96,6 +96,15 @@ config COMPILE_TEST
here. If you are a user/distributor, say N here to exclude useless
drivers to be distributed.
config HEADER_TEST
bool "Compile test headers that should be standalone compilable"
help
Compile test headers listed in header-test-y target to ensure they are
self-contained, i.e. compilable as standalone units.
If you are a developer or tester and want to ensure the requested
headers are self-contained, say Y here. Otherwise, choose N.
config LOCALVERSION
string "Local version - append to kernel release"
help

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@ -294,6 +294,15 @@ quiet_cmd_cc_lst_c = MKLST $@
$(obj)/%.lst: $(src)/%.c FORCE
$(call if_changed_dep,cc_lst_c)
# Dummy C sources for header test (header-test-y target)
# ---------------------------------------------------------------------------
quiet_cmd_header_test = HDRTEST $@
cmd_header_test = echo "\#include \"$*.h\"" > $@
$(obj)/%.hdrtest.c:
$(call cmd,header_test)
# Compile assembler sources (.S)
# ---------------------------------------------------------------------------

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@ -66,6 +66,9 @@ extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
endif
# Test self-contained headers
extra-$(CONFIG_HEADER_TEST) += $(patsubst %.h,%.hdrtest.o,$(header-test-y))
# Add subdir path
extra-y := $(addprefix $(obj)/,$(extra-y))