| c16b137e | 11-Jan-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
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")
- 8
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
Kbuild.include")
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.
.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 <yamada.masahiro@socionext.com>
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| 368a0dfb | 11-Jan-2019 |
Masahiro Yamada <yamada.masahiro@socionext.com> |
kbuild: add .DELETE_ON_ERROR special target
Linux commit 9c2af1c7377a8a6ef86e5cabf80978f3dbbb25c0
If Make gets a fatal signal while a shell is executing, it may delete
the target file that the reci
kbuild: add .DELETE_ON_ERROR special target
Linux commit 9c2af1c7377a8a6ef86e5cabf80978f3dbbb25c0
If Make gets a fatal signal while a shell is executing, it may delete
the target file that the recipe was supposed to update. This is needed
to make sure that it is remade from scratch when Make is next run; if
Make is interrupted after the recipe has begun to write the target file,
it results in an incomplete file whose time stamp is newer than that
of the prerequisites files. Make automatically deletes the incomplete
file on interrupt unless the target is marked .PRECIOUS.
The situation is just the same as when the shell fails for some reasons.
Usually when a recipe line fails, if it has changed the target file at
all, the file is corrupted, or at least it is not completely updated.
Yet the file’s time stamp says that it is now up to date, so the next
time Make runs, it will not try to update that file.
However, Make does not cater to delete the incomplete target file in
this case. We need to add .DELETE_ON_ERROR somewhere in the Makefile
to request it.
scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
show more ...
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