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Subject[PATCH 3/8] kbuild: refactor modversions build rules
Date
Let $(CC) compile objects into normal files *.o instead of .tmp_*.o
whether CONFIG_MODVERSIONS is enabled or not. This will help simplify
build rules a lot.

I guess the reason of using .tmp_*.o for intermediate objects was
to avoid leaving incomplete *.o file (, whose timestamp says it is
up-to-date) when the genksyms tool failed for some reasons.

It no longer matters because any targets are deleted on errors since
commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target").

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

scripts/Makefile.build | 54 ++++++++++++++++----------------------------------
1 file changed, 17 insertions(+), 37 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 7af21a8..7f3ca6e 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -154,35 +154,30 @@ $(obj)/%.ll: $(src)/%.c FORCE
# (See cmd_cc_o_c + relevant part of rule_cc_o_c)

quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
+ cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<

-ifndef CONFIG_MODVERSIONS
-cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
-
-else
+ifdef CONFIG_MODVERSIONS
# When module versioning is enabled the following steps are executed:
-# o compile a .tmp_<file>.o from <file>.c
-# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
-# not export symbols, we just rename .tmp_<file>.o to <file>.o and
-# are done.
+# o compile a <file>.o from <file>.c
+# o if <file>.o doesn't contain a __ksymtab version, i.e. does
+# not export symbols, it's done.
# o otherwise, we calculate symbol versions using the good old
# genksyms on the preprocessed source and postprocess them in a way
# that they are usable as a linker script
-# o generate <file>.o from .tmp_<file>.o using the linker to
+# o generate .tmp_<file>.o from <file>.o using the linker to
# replace the unresolved symbols __crc_exported_symbol with
# the actual value of the checksum generated by genksyms
-
-cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
+# o remove .tmp_<file>.o to <file>.o

cmd_modversions_c = \
- if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
+ if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
> $(@D)/.tmp_$(@F:.o=.ver); \
\
- $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
+ $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
-T $(@D)/.tmp_$(@F:.o=.ver); \
- rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
- else \
mv -f $(@D)/.tmp_$(@F) $@; \
+ rm -f $(@D)/.tmp_$(@F:.o=.ver); \
fi;
endif

@@ -241,19 +236,12 @@ ifneq ($(RETPOLINE_CFLAGS),)
endif
endif

-
-ifdef CONFIG_MODVERSIONS
-objtool_o = $(@D)/.tmp_$(@F)
-else
-objtool_o = $(@)
-endif
-
# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
cmd_objtool = $(if $(patsubst y%,, \
$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
- $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
+ $(__objtool_obj) $(objtool_args) $@;)
objtool_obj = $(if $(patsubst y%,, \
$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
$(__objtool_obj))
@@ -357,34 +345,26 @@ $(obj)/%.s: $(src)/%.S FORCE
$(call if_changed_dep,cpp_s_S)

quiet_cmd_as_o_S = AS $(quiet_modtag) $@
+ cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<

-ifndef CONFIG_MODVERSIONS
-cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
-
-else
+ifdef CONFIG_MODVERSIONS

ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)

-ifeq ($(ASM_PROTOTYPES),)
-cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
-
-else
+ifneq ($(ASM_PROTOTYPES),)

# versioning matches the C process described above, with difference that
# we parse asm-prototypes.h C header to get function definitions.

-cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
-
cmd_modversions_S = \
- if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
+ if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
> $(@D)/.tmp_$(@F:.o=.ver); \
\
- $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
+ $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
-T $(@D)/.tmp_$(@F:.o=.ver); \
- rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
- else \
mv -f $(@D)/.tmp_$(@F) $@; \
+ rm -f $(@D)/.tmp_$(@F:.o=.ver); \
fi;
endif
endif
--
2.7.4
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