* Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote: > 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. > > .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 which could cause 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 mostly in there. Therefore, mark > $(targets) as .SECONDARY. It means primary targets are also marked > as .SECONDARY, but I do not see any drawback for this. > > I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This > will make Kbuild search for non-existing .*.cmd files, but this is > not a noticeable performance issue. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > Acked-by: Frank Rowand <frowand.list@xxxxxxxxx> > --- > arch/arc/boot/dts/Makefile | 2 -- > arch/arm/crypto/Makefile | 2 +- > arch/arm64/crypto/Makefile | 2 +- > arch/metag/boot/dts/Makefile | 2 -- > arch/sparc/vdso/Makefile | 4 +--- > arch/x86/entry/vdso/Makefile | 4 +--- Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
