lkml.org 
[lkml]   [2018]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 01/21] kbuild: remove kbuild cache
On Mon, Mar 26, 2018 at 10:29 PM, Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
> The kbuild cache was introduced to remember the result of shell
> commands, some of which are expensive to compute, such as
> $(call cc-option,...).
>
> However, this turned out not so clever as I had first expected.
> Actually, it is problematic. For example, "$(CC) -print-file-name"
> is cached. If the compiler is updated, the stale search path causes
> build error, which is difficult to figure out. Another problem
> scenario is cache files could be touched while install targets are
> running under the root permission. We can patch them if desired,
> but the build infrastructure is getting uglier and uglier.
>
> Now, we are going to move compiler flag tests to the configuration
> phase. If this is completed, the result of compiler tests will be
> naturally cached in the .config file. We will not have performance
> issues of incremental building since this testing only happens at
> Kconfig time.
>
> To start this work with a cleaner code base, remove the kbuild
> cache first.
>
> Revert the following commits:
> Commit 9a234a2e3843 ("kbuild: create directory for make cache only when necessary")
> Commit e17c400ae194 ("kbuild: shrink .cache.mk when it exceeds 1000 lines")
> Commit 4e56207130ed ("kbuild: Cache a few more calls to the compiler")
> Commit 3298b690b21c ("kbuild: Add a cache for generated variables")
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

--
Kees Cook
Pixel Security

\
 
 \ /
  Last update: 2018-03-28 05:27    [W:0.370 / U:1.740 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site