kbuild: make cc-version available in kbuild files
Move $(CC) support functions to Kbuild.include so they are available in the kbuild files. In addition the following was done: o as-option documented in Documentation/kbuild/makefiles.txt o Moved documentation to new section to match new scope of functions o added cc-ifversion used to conditionally select a text string dependent on actual $(CC) version o documented cc-ifversion o change so Kbuild.include is read before the kbuild file Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
This commit is contained in:
Sam Ravnborg
parent
b39927cf4c
commit
20a468b513
4 changed files with 136 additions and 102 deletions
|
|
@ -17,6 +17,7 @@ This document describes the Linux kernel Makefiles.
|
|||
--- 3.8 Command line dependency
|
||||
--- 3.9 Dependency tracking
|
||||
--- 3.10 Special Rules
|
||||
--- 3.11 $(CC) support functions
|
||||
|
||||
=== 4 Host Program support
|
||||
--- 4.1 Simple Host Program
|
||||
|
|
@ -38,7 +39,6 @@ This document describes the Linux kernel Makefiles.
|
|||
--- 6.6 Commands useful for building a boot image
|
||||
--- 6.7 Custom kbuild commands
|
||||
--- 6.8 Preprocessing linker scripts
|
||||
--- 6.9 $(CC) support functions
|
||||
|
||||
=== 7 Kbuild Variables
|
||||
=== 8 Makefile language
|
||||
|
|
@ -385,6 +385,102 @@ more details, with real examples.
|
|||
to prerequisites are referenced with $(src) (because they are not
|
||||
generated files).
|
||||
|
||||
--- 3.11 $(CC) support functions
|
||||
|
||||
The kernel may be build with several different versions of
|
||||
$(CC), each supporting a unique set of features and options.
|
||||
kbuild provide basic support to check for valid options for $(CC).
|
||||
$(CC) is useally the gcc compiler, but other alternatives are
|
||||
available.
|
||||
|
||||
as-option
|
||||
as-option is used to check if $(CC) when used to compile
|
||||
assembler (*.S) files supports the given option. An optional
|
||||
second option may be specified if first option are not supported.
|
||||
|
||||
Example:
|
||||
#arch/sh/Makefile
|
||||
cflags-y += $(call as-option,-Wa$(comma)-isa=$(isa-y),)
|
||||
|
||||
In the above example cflags-y will be assinged the the option
|
||||
-Wa$(comma)-isa=$(isa-y) if it is supported by $(CC).
|
||||
The second argument is optional, and if supplied will be used
|
||||
if first argument is not supported.
|
||||
|
||||
cc-option
|
||||
cc-option is used to check if $(CC) support a given option, and not
|
||||
supported to use an optional second option.
|
||||
|
||||
Example:
|
||||
#arch/i386/Makefile
|
||||
cflags-y += $(call cc-option,-march=pentium-mmx,-march=i586)
|
||||
|
||||
In the above example cflags-y will be assigned the option
|
||||
-march=pentium-mmx if supported by $(CC), otherwise -march-i586.
|
||||
The second argument to cc-option is optional, and if omitted
|
||||
cflags-y will be assigned no value if first option is not supported.
|
||||
|
||||
cc-option-yn
|
||||
cc-option-yn is used to check if gcc supports a given option
|
||||
and return 'y' if supported, otherwise 'n'.
|
||||
|
||||
Example:
|
||||
#arch/ppc/Makefile
|
||||
biarch := $(call cc-option-yn, -m32)
|
||||
aflags-$(biarch) += -a32
|
||||
cflags-$(biarch) += -m32
|
||||
|
||||
In the above example $(biarch) is set to y if $(CC) supports the -m32
|
||||
option. When $(biarch) equals to y the expanded variables $(aflags-y)
|
||||
and $(cflags-y) will be assigned the values -a32 and -m32.
|
||||
|
||||
cc-option-align
|
||||
gcc version >= 3.0 shifted type of options used to speify
|
||||
alignment of functions, loops etc. $(cc-option-align) whrn used
|
||||
as prefix to the align options will select the right prefix:
|
||||
gcc < 3.00
|
||||
cc-option-align = -malign
|
||||
gcc >= 3.00
|
||||
cc-option-align = -falign
|
||||
|
||||
Example:
|
||||
CFLAGS += $(cc-option-align)-functions=4
|
||||
|
||||
In the above example the option -falign-functions=4 is used for
|
||||
gcc >= 3.00. For gcc < 3.00 -malign-functions=4 is used.
|
||||
|
||||
cc-version
|
||||
cc-version return 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 the -mregparm=3 were broken in some gcc version
|
||||
even though the option was accepted by gcc.
|
||||
|
||||
Example:
|
||||
#arch/i386/Makefile
|
||||
cflags-y += $(shell \
|
||||
if [ $(call 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 test the version of $(CC) and equals last argument if
|
||||
version expression is true.
|
||||
|
||||
Example:
|
||||
#fs/reiserfs/Makefile
|
||||
EXTRA_CFLAGS := $(call cc-ifversion, -lt, 0402, -O1)
|
||||
|
||||
In this example EXTRA_CFLAGS will be assigned the value -O1 if the
|
||||
$(CC) version is less than 4.2.
|
||||
cc-ifversion takes all the shell operators:
|
||||
-eq, -ne, -lt, -le, -gt, and -ge
|
||||
The third parameter may be a text as in this example, but it may also
|
||||
be an expanded variable or a macro.
|
||||
|
||||
|
||||
=== 4 Host Program support
|
||||
|
||||
|
|
@ -973,74 +1069,6 @@ When kbuild executes the following steps are followed (roughly):
|
|||
architecture specific files.
|
||||
|
||||
|
||||
--- 6.9 $(CC) support functions
|
||||
|
||||
The kernel may be build with several different versions of
|
||||
$(CC), each supporting a unique set of features and options.
|
||||
kbuild provide basic support to check for valid options for $(CC).
|
||||
$(CC) is useally the gcc compiler, but other alternatives are
|
||||
available.
|
||||
|
||||
cc-option
|
||||
cc-option is used to check if $(CC) support a given option, and not
|
||||
supported to use an optional second option.
|
||||
|
||||
Example:
|
||||
#arch/i386/Makefile
|
||||
cflags-y += $(call cc-option,-march=pentium-mmx,-march=i586)
|
||||
|
||||
In the above example cflags-y will be assigned the option
|
||||
-march=pentium-mmx if supported by $(CC), otherwise -march-i586.
|
||||
The second argument to cc-option is optional, and if omitted
|
||||
cflags-y will be assigned no value if first option is not supported.
|
||||
|
||||
cc-option-yn
|
||||
cc-option-yn is used to check if gcc supports a given option
|
||||
and return 'y' if supported, otherwise 'n'.
|
||||
|
||||
Example:
|
||||
#arch/ppc/Makefile
|
||||
biarch := $(call cc-option-yn, -m32)
|
||||
aflags-$(biarch) += -a32
|
||||
cflags-$(biarch) += -m32
|
||||
|
||||
In the above example $(biarch) is set to y if $(CC) supports the -m32
|
||||
option. When $(biarch) equals to y the expanded variables $(aflags-y)
|
||||
and $(cflags-y) will be assigned the values -a32 and -m32.
|
||||
|
||||
cc-option-align
|
||||
gcc version >= 3.0 shifted type of options used to speify
|
||||
alignment of functions, loops etc. $(cc-option-align) whrn used
|
||||
as prefix to the align options will select the right prefix:
|
||||
gcc < 3.00
|
||||
cc-option-align = -malign
|
||||
gcc >= 3.00
|
||||
cc-option-align = -falign
|
||||
|
||||
Example:
|
||||
CFLAGS += $(cc-option-align)-functions=4
|
||||
|
||||
In the above example the option -falign-functions=4 is used for
|
||||
gcc >= 3.00. For gcc < 3.00 -malign-functions=4 is used.
|
||||
|
||||
cc-version
|
||||
cc-version return 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 the -mregparm=3 were broken in some gcc version
|
||||
even though the option was accepted by gcc.
|
||||
|
||||
Example:
|
||||
#arch/i386/Makefile
|
||||
cflags-y += $(shell \
|
||||
if [ $(call cc-version) -ge 0300 ] ; then \
|
||||
echo "-mregparm=3"; fi ;)
|
||||
|
||||
In the above example -mregparm=3 is only used for gcc version greater
|
||||
than or equal to gcc 3.0.
|
||||
|
||||
|
||||
=== 7 Kbuild Variables
|
||||
|
||||
The top Makefile exports the following variables:
|
||||
|
|
|
|||
32
Makefile
32
Makefile
|
|
@ -258,38 +258,6 @@ endif
|
|||
|
||||
export quiet Q KBUILD_VERBOSE
|
||||
|
||||
######
|
||||
# cc support functions to be used (only) in arch/$(ARCH)/Makefile
|
||||
# See documentation in Documentation/kbuild/makefiles.txt
|
||||
|
||||
# as-option
|
||||
# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
|
||||
|
||||
as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
|
||||
-xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
|
||||
else echo "$(2)"; fi ;)
|
||||
|
||||
# cc-option
|
||||
# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
|
||||
|
||||
cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
|
||||
> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
|
||||
|
||||
# cc-option-yn
|
||||
# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
|
||||
cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
|
||||
> /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
|
||||
|
||||
# cc-option-align
|
||||
# Prefix align with either -falign or -malign
|
||||
cc-option-align = $(subst -functions=0,,\
|
||||
$(call cc-option,-falign-functions=0,-malign-functions=0))
|
||||
|
||||
# cc-version
|
||||
# Usage gcc-ver := $(call cc-version $(CC))
|
||||
cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
|
||||
$(if $(1), $(1), $(CC)))
|
||||
|
||||
|
||||
# Look for make include files relative to root of kernel src
|
||||
MAKEFLAGS += --include-dir=$(srctree)
|
||||
|
|
|
|||
|
|
@ -44,6 +44,43 @@ define filechk
|
|||
fi
|
||||
endef
|
||||
|
||||
######
|
||||
# cc support functions to be used (only) in arch/$(ARCH)/Makefile
|
||||
# See documentation in Documentation/kbuild/makefiles.txt
|
||||
|
||||
# as-option
|
||||
# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
|
||||
|
||||
as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
|
||||
-xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
|
||||
else echo "$(2)"; fi ;)
|
||||
|
||||
# cc-option
|
||||
# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
|
||||
|
||||
cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
|
||||
> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
|
||||
|
||||
# cc-option-yn
|
||||
# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
|
||||
cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
|
||||
> /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
|
||||
|
||||
# cc-option-align
|
||||
# Prefix align with either -falign or -malign
|
||||
cc-option-align = $(subst -functions=0,,\
|
||||
$(call cc-option,-falign-functions=0,-malign-functions=0))
|
||||
|
||||
# cc-version
|
||||
# Usage gcc-ver := $(call cc-version, $(CC))
|
||||
cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
|
||||
$(if $(1), $(1), $(CC)))
|
||||
|
||||
# cc-ifversion
|
||||
# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
|
||||
cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
|
||||
echo $(3); fi;)
|
||||
|
||||
###
|
||||
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
|
||||
# Usage:
|
||||
|
|
|
|||
|
|
@ -10,11 +10,12 @@ __build:
|
|||
# Read .config if it exist, otherwise ignore
|
||||
-include .config
|
||||
|
||||
include scripts/Kbuild.include
|
||||
|
||||
# The filename Kbuild has precedence over Makefile
|
||||
kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
|
||||
include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)
|
||||
|
||||
include scripts/Kbuild.include
|
||||
include scripts/Makefile.lib
|
||||
|
||||
ifdef host-progs
|
||||
|
|
|
|||
Loading…
Reference in a new issue