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authorMasahiro Yamada <yamada.masahiro@socionext.com>2018-05-28 18:22:08 +0900
committerMasahiro Yamada <yamada.masahiro@socionext.com>2018-06-11 09:16:28 +0900
commit8373b7d9d174d577d93c6d4de46ae207f0b8d55b (patch)
treeb69faa7e0a334125491cc0184d9efe760dd8f462 /Documentation/kbuild
parentcaa91ba53eb1c92d00abdf5b6c67a310d2b4c2d9 (diff)
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Documentation: kconfig: add recommended way to describe compiler support
It would be nice if the source code is written in the same style. This proposes the convention for describing the compiler capability in Kconfig. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'Documentation/kbuild')
-rw-r--r--Documentation/kbuild/kconfig-language.txt18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index 0e966e8f9ec7..a4eb01843c04 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -473,6 +473,24 @@ config option to 'y' no matter the dependencies.
The dependencies are moved to the symbol GENERIC_IOMAP and we avoid the
situation where select forces a symbol equals to 'y'.
+Adding features that need compiler support
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+There are several features that need compiler support. The recommended way
+to describe the dependency on the compiler feature is to use "depends on"
+followed by a test macro.
+
+config CC_STACKPROTECTOR
+ bool "Stack Protector buffer overflow detection"
+ depends on $(cc-option,-fstack-protector)
+ ...
+
+If you need to expose a compiler capability to makefiles and/or C source files,
+CC_HAS_ is the recommended prefix for the config option.
+
+config CC_HAS_STACKPROTECTOR_NONE
+ def_bool $(cc-option,-fno-stack-protector)
+
Build as module only
~~~~~~~~~~~~~~~~~~~~
To restrict a component build to module-only, qualify its config symbol
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