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Commit f77bf014 authored by Sam Ravnborg's avatar Sam Ravnborg
Browse files

kbuild: introduce ccflags-y, asflags-y and ldflags-y 



Introduce ccflags-y, asflags-y and ldflags-y so we soon can
deprecate use of EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS.
This patch does not touch any in-tree users - thats next round.
Lets get this committed first and then fix the users of the
soon to be deprecated variants next.

The rationale behind this change is to introduce support for
makefile fragments like:

ccflags-$(CONFIG_WHATEVER_DEBUG) := -DDEBUG

As a replacement for the uglier:
ifeq ($(CONFIG_WHATEVER_DEBUG),y)
        EXTRA_CFLAGS := -DDEBUG
endif

Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent 06c5040c

Documentation/kbuild/makefiles.txt

+18 −19
Original line number Diff line number Diff line
@@ -276,40 +276,39 @@ more details, with real examples. 


--- 3.7 Compilation flags



    EXTRA_CFLAGS, EXTRA_AFLAGS, EXTRA_LDFLAGS

    ccflags-y, asflags-y and ldflags-y

	The three flags listed above applies only to the kbuild makefile

	where they are assigned. They are used for all the normal

	cc, as and ld invocation happenign during a recursive build.

	Note: Flags with the same behaviour were previously named:

	EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS.

	They are yet supported but their use are deprecated.



	All the EXTRA_ variables apply only to the kbuild makefile

	where they are assigned. The EXTRA_ variables apply to all

	commands executed in the kbuild makefile.



	$(EXTRA_CFLAGS) specifies options for compiling C files with

	$(CC).

	ccflags-y specifies options for compiling C files with $(CC).



	Example:

		# drivers/sound/emu10k1/Makefile

		EXTRA_CFLAGS += -I$(obj)

		ifdef DEBUG

		    EXTRA_CFLAGS += -DEMU10K1_DEBUG

		endif

		ccflags-y += -I$(obj)

		ccflags-$(DEBUG) += -DEMU10K1_DEBUG





	This variable is necessary because the top Makefile owns the

	variable $(KBUILD_CFLAGS) and uses it for compilation flags for the

	entire tree.



	$(EXTRA_AFLAGS) is a similar string for per-directory options

	asflags-y is a similar string for per-directory options

	when compiling assembly language source.



	Example:

		#arch/x86_64/kernel/Makefile

		EXTRA_AFLAGS := -traditional

		asflags-y := -traditional





	$(EXTRA_LDFLAGS) is a string for per-directory options to $(LD).

	ldflags-y is a string for per-directory options to $(LD).



	Example:

		#arch/m68k/fpsp040/Makefile

		EXTRA_LDFLAGS := -x

		ldflags-y := -x



    CFLAGS_$@, AFLAGS_$@
@@ -495,9 +494,9 @@ more details, with real examples. 


	Example:

		#fs/reiserfs/Makefile

		EXTRA_CFLAGS := $(call cc-ifversion, -lt, 0402, -O1)

		ccflags-y := $(call cc-ifversion, -lt, 0402, -O1)



	In this example, EXTRA_CFLAGS will be assigned the value -O1 if the

	In this example, ccflags-y 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
@@ -783,7 +782,7 @@ When kbuild executes, the following steps are followed (roughly): 
	Example:

		#arch/s390/Makefile

		LDFLAGS         := -m elf_s390

	Note: EXTRA_LDFLAGS can be used to further customise

	Note: ldflags-y can be used to further customise

	the flags used. See chapter 3.7.



    LDFLAGS_MODULE	Options for $(LD) when linking modules
@@ -1100,7 +1099,7 @@ When kbuild executes, the following steps are followed (roughly): 


	When building the *.lds target, kbuild uses the variables:

	KBUILD_CPPFLAGS	: Set in top-level Makefile

	EXTRA_CPPFLAGS	: May be set in the kbuild makefile

	cppflags-y	: May be set in the kbuild makefile

	CPPFLAGS_$(@F)  : Target specific flags.

	                  Note that the full filename is used in this

	                  assignment.

scripts/Makefile.build

+4 −0
Original line number Diff line number Diff line
@@ -22,6 +22,10 @@ EXTRA_AFLAGS := 
EXTRA_CFLAGS   :=

EXTRA_CPPFLAGS :=

EXTRA_LDFLAGS  :=

asflags-y  :=

ccflags-y  :=

cppflags-y :=

ldflags-y  :=



# Read .config if it exist, otherwise ignore

-include include/config/auto.conf

scripts/Makefile.lib

+11 −5
Original line number Diff line number Diff line 
# Backward compatibility

asflags-y  += $(EXTRA_AFLAGS)

ccflags-y  += $(EXTRA_CFLAGS)

cppflags-y += $(EXTRA_CPPFLAGS)

ldflags-y  += $(EXTRA_LDFLAGS)



# Figure out what we need to build from the various variables

# ===========================================================================
@@ -84,9 +90,9 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))" 
modname_flags  = $(if $(filter 1,$(words $(modname))),\

                 -D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")



_c_flags       = $(KBUILD_CFLAGS) $(EXTRA_CFLAGS) $(CFLAGS_$(basetarget).o)

_a_flags       = $(KBUILD_AFLAGS) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)

_cpp_flags     = $(KBUILD_CPPFLAGS) $(EXTRA_CPPFLAGS) $(CPPFLAGS_$(@F))

_c_flags       = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(basetarget).o)

_a_flags       = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(basetarget).o)

_cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))



# If building the kernel in a separate objtree expand all occurrences

# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
@@ -115,7 +121,7 @@ a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \ 


cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(__cpp_flags)



ld_flags       = $(LDFLAGS) $(EXTRA_LDFLAGS)

ld_flags       = $(LDFLAGS) $(ldflags-y)



# Finds the multi-part object the current object will be linked into

modname-multi = $(sort $(foreach m,$(multi-used),\
@@ -145,7 +151,7 @@ $(obj)/%:: $(src)/%_shipped 
# ---------------------------------------------------------------------------



quiet_cmd_ld = LD      $@

cmd_ld = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_$(@F)) \

cmd_ld = $(LD) $(LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F)) \

	       $(filter-out FORCE,$^) -o $@ 



# Objcopy

scripts/makelst

+2 −2
Original line number Diff line number Diff line
@@ -3,8 +3,8 @@ 
# with correct relocations from System.map

# Requires the following lines in makefile:

#%.lst: %.c

#	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $(CFLAGS_$@) -g -c -o $*.o $<

#	$(srctree)/scripts/makelst $*.o $(objtree)/System.map $(OBJDUMP)

#	$(CC) $(c_flags) -g -c -o $*.o $< &&

#	$(srctree)/scripts/makelst $*.o System.map $(OBJDUMP) > $@

#

# Copyright (C) 2000 IBM Corporation

# Author(s): DJ Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)