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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>
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 In the above example, -Wno-unused-but-set-variable will be added to
KBUILD_CFLAGS only if gcc really accepts it. 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
cc-ifversion tests the version of $(CC) and equals the fourth parameter 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 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-disable-warning = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
# cc-version
cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
# cc-ifversion # cc-ifversion
# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) # 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 # cc-ldoption
# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)