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From:   Geert Uytterhoeven <geert+renesas@glider.be>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Jonathan Corbet <corbet@lwn.net>, Arnd Bergmann <arnd@arndb.de>
Cc:     linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 1/2] Documentation/kbuild: Document COMPILE_TEST dependencies
Date:   Tue,  8 Dec 2020 16:28:56 +0100
Message-Id: <20201208152857.2162093-2-geert+renesas@glider.be>
In-Reply-To: <20201208152857.2162093-1-geert+renesas@glider.be>
References: <20201208152857.2162093-1-geert+renesas@glider.be>
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Document best practises for using COMPILE_TEST dependencies.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 Documentation/kbuild/kconfig-language.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 1cf1aebdd6cdf8fa..2b746332d8aa6bce 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -553,6 +553,17 @@ with "depends on m".  E.g.::
 
 limits FOO to module (=m) or disabled (=n).
 
+Compile-testing
+~~~~~~~~~~~~~~~
+If a config symbol has a dependency, but the code controlled by the config
+symbol can still be compiled if the dependency is not met, it is encouraged to
+increase build coverage by adding an "|| COMPILE_TEST" clause to the
+dependency.  This is especially useful for drivers for more exotic hardware, as
+it allows continuous-integration systems to compile-test the code on a more
+common system, and detect bugs that way.
+Note that compile-tested code should avoid crashing when run on a system where
+the dependency is not met.
+
 Kconfig recursive dependency limitations
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-- 
2.25.1