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kbuild: remove cc-version macro

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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>
This commit is contained in:
Masahiro Yamada 2019-03-01 16:10:21 +09:00
parent 00250b5219
commit d3a918c659
2 changed files with 1 additions and 21 deletions
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17
Documentation/kbuild/makefiles.txt
View File

@ -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

5
scripts/Kbuild.include
View File

@ -134,12 +134,9 @@ cc-option-yn = $(call try-run,\
cc-disable-warning = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
# cc-version
cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
# cc-ifversion
# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4))
cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
# cc-ldoption
# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)