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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-03-01 16:10:21 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-03-04 22:34:59 +0900 |
| commit | d3a918c659ed0998ac668de3973e81bab81dde74 (patch) | |
| tree | 31f247bad04c26b04ed824cec7d3ada47d2bba1e /Documentation/kbuild/makefiles.txt | |
| parent | 00250b52190bc30fb83ea464d9e921b53c07aaa1 (diff) | |
| download | lwn-d3a918c659ed0998ac668de3973e81bab81dde74.tar.gz lwn-d3a918c659ed0998ac668de3973e81bab81dde74.zip | |
kbuild: remove cc-version macro
There is no more direct user of this macro; it is only used by
cc-ifversion.
Calling this macro is not efficient since it invokes the compiler to
get the compiler version. CONFIG_GCC_VERSION is already calculated in
the Kconfig stage, so Makefile can reuse it.
Here is a note about the slight difference between cc-version and
CONFIG_GCC_VERSION:
When using Clang, cc-version is evaluated to '0402' because Clang
defines __GNUC__ and __GNUC__MINOR__, and looks like GCC 4.2 in the
version point of view. On the other hand, CONFIG_GCC_VERSION=0
when $(CC) is clang.
There are currently two users of cc-ifversion:
arch/mips/loongson64/Platform
arch/powerpc/Makefile
They are not affected by this change.
The format of cc-version is <major><minor>, while CONFIG_GCC_VERSION
<major><minor><patch>. I adjusted cc-ifversion for the difference of
the number of digits.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'Documentation/kbuild/makefiles.txt')
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 48eab0bb1183..f124be6e4c3a 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -499,23 +499,6 @@ more details, with real examples. In the above example, -Wno-unused-but-set-variable will be added to KBUILD_CFLAGS only if gcc really accepts it. - cc-version - cc-version returns a numerical version of the $(CC) compiler version. - The format is <major><minor> where both are two digits. So for example - gcc 3.41 would return 0341. - cc-version is useful when a specific $(CC) version is faulty in one - area, for example -mregparm=3 was broken in some gcc versions - even though the option was accepted by gcc. - - Example: - #arch/x86/Makefile - cflags-y += $(shell \ - if [ $(cc-version) -ge 0300 ] ; then \ - echo "-mregparm=3"; fi ;) - - In the above example, -mregparm=3 is only used for gcc version greater - than or equal to gcc 3.0. - cc-ifversion cc-ifversion tests the version of $(CC) and equals the fourth parameter if version expression is true, or the fifth (if given) if the version |