Commit c16b137e authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Tom Rini
Browse files

kbuild: add .SECONDARY special target to scripts/Kbuild.include

Based on the following Linux commits:

 - 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove
   .PRECIOUS markers")

 - 8e9b61b293d9 ("kbuild: move .SECONDARY special target to

GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.

Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped

A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.

    Prerequisites of this special target are treated as intermediate
    files but are never automatically deleted.

    When make is interrupted during execution, it may delete the target
    file it is updating if the file was modified since make started.
    If you mark the file as precious, make will never delete the file
    if interrupted.

Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.

The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.

.SECONDARY with no prerequisites causes all targets to be treated as
secondary. This agrees the policy of Kbuild.

scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada's avatarMasahiro Yamada <>
parent 368a0dfb
......@@ -43,9 +43,6 @@ endif
$(Q)$(MAKE) $(build)=$(ARCH_PATH) dtbs
.SECONDARY: $(obj)/dt.dtb.S $(obj)/dt-spl.dtb.S
ifeq ($(CONFIG_SPL_BUILD),y)
obj-$(CONFIG_OF_EMBED) := dt-spl.dtb.o
# support "out-of-tree" build for dtb-spl
......@@ -26,7 +26,6 @@ LIB = $(obj)/libstubs.o
LIBOBJS-$(CONFIG_PPC) += ppc_longjmp.o ppc_setjmp.o
LIBOBJS-y += stubs.o
.SECONDARY: $(call objectify,$(COBJS))
targets += $(patsubst $(obj)/%,%,$(LIB)) $(COBJS) $(LIBOBJS-y)
LIBOBJS := $(addprefix $(obj)/,$(LIBOBJS-y))
......@@ -11,9 +11,6 @@ targets += $(objs-before-objcopy)
$(foreach m, $(objs-before-objcopy), $(eval CFLAGS_REMOVE_$m := -msoft-float))
ccflags-y := -mhard-float -fkeep-inline-functions
# Do not delete intermidiate files (*.o)
.SECONDARY: $(call objectify, $(objs-before-objcopy))
obj-y := $(objs-before-objcopy:.o=_.o)
OBJCOPYFLAGS := -R .gnu.attributes
......@@ -318,6 +318,9 @@ endif
# delete partially updated (i.e. corrupted) files on error
# do not delete intermediate files automatically
SPL_ := SPL_
ifeq ($(CONFIG_TPL_BUILD),y)
......@@ -331,8 +331,6 @@ quiet_cmd_asn1_compiler = ASN.1 $@
cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
$(subst .h,.c,$@) $(subst .c,.h,$@)
.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
$(call cmd,asn1_compiler)
......@@ -214,7 +214,6 @@ endef
quiet_cmd_flex = LEX $@
cmd_flex = $(LEX) -o$@ -L $<
.PRECIOUS: $(obj)/%.lex.c
$(obj)/%.lex.c: $(src)/%.l FORCE
$(call if_changed,flex)
......@@ -223,14 +222,12 @@ $(obj)/%.lex.c: $(src)/%.l FORCE
quiet_cmd_bison = YACC $@
cmd_bison = $(YACC) -o$@ -t -l $<
.PRECIOUS: $(obj)/
$(obj)/ $(src)/%.y FORCE
$(call if_changed,bison)
quiet_cmd_bison_h = YACC $@
cmd_bison_h = $(YACC) -o/dev/null --defines=$@ -t -l $<
.PRECIOUS: $(obj)/
$(obj)/ $(src)/%.y FORCE
$(call if_changed,bison_h)
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