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authorMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>2018-11-06 22:52:11 +0100
committerMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>2018-11-08 11:33:52 +0100
commit24efee412c75843755da0ddd7bbc2db2ce9129f5 (patch)
treebc483f7c64a7859cb6aa1df67eda33f94fb5eab7
parent8bd66d147c88bd441178c7b4c774ae5a185f19b8 (diff)
downloadlinux-24efee412c75843755da0ddd7bbc2db2ce9129f5.tar.bz2
Compiler Attributes: improve explanation of header
Explain better what "optional" attributes are, and avoid calling them so to avoid confusion. Simply retain "Optional" as a word to look for in the comments. Moreover, add a couple sentences to explain a bit more the intention and the documentation links. Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
-rw-r--r--include/linux/compiler_attributes.h14
1 files changed, 9 insertions, 5 deletions
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index 6b28c1b7310c..f8c400ba1929 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -4,22 +4,26 @@
/*
* The attributes in this file are unconditionally defined and they directly
- * map to compiler attribute(s) -- except those that are optional.
+ * map to compiler attribute(s), unless one of the compilers does not support
+ * the attribute. In that case, __has_attribute is used to check for support
+ * and the reason is stated in its comment ("Optional: ...").
*
* Any other "attributes" (i.e. those that depend on a configuration option,
* on a compiler, on an architecture, on plugins, on other attributes...)
* should be defined elsewhere (e.g. compiler_types.h or compiler-*.h).
+ * The intention is to keep this file as simple as possible, as well as
+ * compiler- and version-agnostic (e.g. avoiding GCC_VERSION checks).
*
* This file is meant to be sorted (by actual attribute name,
* not by #define identifier). Use the __attribute__((__name__)) syntax
* (i.e. with underscores) to avoid future collisions with other macros.
- * If an attribute is optional, state the reason in the comment.
+ * Provide links to the documentation of each supported compiler, if it exists.
*/
/*
- * To check for optional attributes, we use __has_attribute, which is supported
- * on gcc >= 5, clang >= 2.9 and icc >= 17. In the meantime, to support
- * 4.6 <= gcc < 5, we implement __has_attribute by hand.
+ * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17.
+ * In the meantime, to support 4.6 <= gcc < 5, we implement __has_attribute
+ * by hand.
*
* sparse does not support __has_attribute (yet) and defines __GNUC_MINOR__
* depending on the compiler used to build it; however, these attributes have