On 03/23/18 06:04, Masahiro Yamada wrote: > GNU Make automatically deletes intermediate files that are updated > in a chain of pattern rules. > > Example 1) %.dtb.o <- %.dtb.S <- %.dtb.S <- %.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. > > .SECONDARY > Prerequisites of this special target are treated as intermediate > files but are never automatically deleted. > > .PRECIOUS > 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. > > Another difference is that .PRECIOUS works with pattern rules whereas > .SECONDARY does not. > > .PRECIOUS: $(obj)/%.lex.c > > works, but > > .SECONDARY: $(obj)/%.lex.c > > has no effect. However, for the reason above, I do not want to use > .PRECIOUS to avoid obscure build breakage. > > The targets specified as .SECONDARY must be explicit. $(targets) > contains all targets that need to include .*.cmd files. So, the > intermediates you want to keep are likely to be contained in > $(targets). So, mark it as .SECONDARY. The exception is when they > are created by $(call cmd,...) instead of $(call if_changed,...) > since the former does not need to include .*.cmd file. In this > case, makefiles need to mark them .SECONDARY by themselves, like > arch/arm(64)/crypto/Makefile. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Acked-by: Frank Rowand <frowand.list@xxxxxxxxx> -Frank > --- > > arch/arc/boot/dts/Makefile | 2 -- > arch/arm/crypto/Makefile | 2 +- > arch/arm64/crypto/Makefile | 2 +- > arch/metag/boot/dts/Makefile | 2 -- > drivers/of/unittest-data/Makefile | 4 ---- > scripts/Makefile.build | 6 ++++-- > scripts/Makefile.lib | 3 --- > 7 files changed, 6 insertions(+), 15 deletions(-) > > diff --git a/arch/arc/boot/dts/Makefile b/arch/arc/boot/dts/Makefile > index 22a4c5d..a83c4f5 100644 > --- a/arch/arc/boot/dts/Makefile > +++ b/arch/arc/boot/dts/Makefile > @@ -9,8 +9,6 @@ endif > obj-y += $(builtindtb-y).dtb.o > dtb-y := $(builtindtb-y).dtb > > -.SECONDARY: $(obj)/$(builtindtb-y).dtb.S > - > # for CONFIG_OF_ALL_DTBS test > dtstree := $(srctree)/$(src) > dtb- := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts)) > diff --git a/arch/arm/crypto/Makefile b/arch/arm/crypto/Makefile > index 30ef8e2..3d59567 100644 > --- a/arch/arm/crypto/Makefile > +++ b/arch/arm/crypto/Makefile > @@ -63,4 +63,4 @@ $(src)/sha256-core.S_shipped: $(src)/sha256-armv4.pl > $(src)/sha512-core.S_shipped: $(src)/sha512-armv4.pl > $(call cmd,perl) > > -.PRECIOUS: $(obj)/sha256-core.S $(obj)/sha512-core.S > +.SECONDARY: $(obj)/sha256-core.S $(obj)/sha512-core.S > diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile > index cee9b8d9..fceb638 100644 > --- a/arch/arm64/crypto/Makefile > +++ b/arch/arm64/crypto/Makefile > @@ -76,4 +76,4 @@ $(src)/sha256-core.S_shipped: $(src)/sha512-armv8.pl > $(src)/sha512-core.S_shipped: $(src)/sha512-armv8.pl > $(call cmd,perlasm) > > -.PRECIOUS: $(obj)/sha256-core.S $(obj)/sha512-core.S > +.SECONDARY: $(obj)/sha256-core.S $(obj)/sha512-core.S > diff --git a/arch/metag/boot/dts/Makefile b/arch/metag/boot/dts/Makefile > index f0a180f..16505aa 100644 > --- a/arch/metag/boot/dts/Makefile > +++ b/arch/metag/boot/dts/Makefile > @@ -12,5 +12,3 @@ endif > > dtb-$(CONFIG_METAG_BUILTIN_DTB) += $(builtindtb-y).dtb > obj-$(CONFIG_METAG_BUILTIN_DTB) += $(builtindtb-y).dtb.o > - > -.SECONDARY: $(obj)/$(builtindtb-y).dtb.S > diff --git a/drivers/of/unittest-data/Makefile b/drivers/of/unittest-data/Makefile > index 333bc4c..0fb87cb 100644 > --- a/drivers/of/unittest-data/Makefile > +++ b/drivers/of/unittest-data/Makefile > @@ -12,7 +12,3 @@ DTC_FLAGS_overlay := -@ > DTC_FLAGS_overlay_bad_phandle := -@ > DTC_FLAGS_overlay_bad_symbol := -@ > DTC_FLAGS_overlay_base := -@ > - > -.PRECIOUS: \ > - $(obj)/%.dtb.S \ > - $(obj)/%.dtb > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index cc081af..4397adb 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -430,8 +430,6 @@ 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 FORCE > $(call if_changed,asn1_compiler) > @@ -590,6 +588,10 @@ $(shell mkdir -p $(obj-dirs)) > endif > endif > > +# Some contained in $(targets) are intermediate artifacts. > +# We never want them to be removed automatically. > +.SECONDARY: $(targets) > + > # Declare the contents of the .PHONY variable as phony. We keep that > # information in a variable se we can use it in if_changed and friends. > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index 7a1fa92..c114ce5 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -183,7 +183,6 @@ endef > quiet_cmd_flex = LEX $@ > cmd_flex = $(LEX) -o$@ -L $< > > -.PRECIOUS: $(obj)/%.lex.c > $(obj)/%.lex.c: $(src)/%.l FORCE > $(call if_changed,flex) > > @@ -192,14 +191,12 @@ $(obj)/%.lex.c: $(src)/%.l FORCE > quiet_cmd_bison = YACC $@ > cmd_bison = $(YACC) -o$@ -t -l $< > > -.PRECIOUS: $(obj)/%.tab.c > $(obj)/%.tab.c: $(src)/%.y FORCE > $(call if_changed,bison) > > quiet_cmd_bison_h = YACC $@ > cmd_bison_h = bison -o/dev/null --defines=$@ -t -l $< > > -.PRECIOUS: $(obj)/%.tab.h > $(obj)/%.tab.h: $(src)/%.y FORCE > $(call if_changed,bison_h) > > -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
