| Message ID | 20200117105358.607910-12-anthony.perard@citrix.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen: Build system improvements | expand |
On 17.01.2020 11:53, Anthony PERARD wrote: > We are going to want $(CFLAGS) to be static and never change during > the build, so introduce new variables that can be use to change the > flags of a single target or of a whole directory. I'm again struggling with the "why": What problem is there with e.g. CFLAGS += -fshort-wchar in a particular Makefile? This doesn't alter the when-to-expand aspect of $(CFLAGS) at all. I have to admit that I'm also a little puzzled by the naming, no matter that it's taken from Linux. It doesn't really seem to fit CFLAGS/AFLAGS and c_flags/a_flags. Jan
On Thu, Jan 30, 2020 at 02:39:43PM +0100, Jan Beulich wrote: > On 17.01.2020 11:53, Anthony PERARD wrote: > I have to admit that I'm also a little puzzled by the naming, no > matter that it's taken from Linux. It doesn't really seem to fit > CFLAGS/AFLAGS and c_flags/a_flags. So I've look into the history of Linux, ccflags-y was introduce to get rid of EXTRA_CFLAGS and especially to have the -y part in the name of the variable. So, instead of ccflags-y and the like, we could use CFLAGS-y in Makefile of subdirectories. For makefiles in subdir, Linux has: CFLAGS_$@ CFLAGS_REMOVE_$@ ccflags-y subdir-ccflags-y so CFLAGS-y would be better (and we can think about the subdir one later).
On 03.02.2020 15:23, Anthony PERARD wrote: > On Thu, Jan 30, 2020 at 02:39:43PM +0100, Jan Beulich wrote: >> On 17.01.2020 11:53, Anthony PERARD wrote: >> I have to admit that I'm also a little puzzled by the naming, no >> matter that it's taken from Linux. It doesn't really seem to fit >> CFLAGS/AFLAGS and c_flags/a_flags. > > So I've look into the history of Linux, ccflags-y was introduce to get > rid of EXTRA_CFLAGS and especially to have the -y part in the name of > the variable. > > So, instead of ccflags-y and the like, we could use CFLAGS-y in Makefile > of subdirectories. > > For makefiles in subdir, Linux has: > CFLAGS_$@ > CFLAGS_REMOVE_$@ > ccflags-y > subdir-ccflags-y > so CFLAGS-y would be better (and we can think about the subdir one > later). In case this doesn't conflict with uses of CFLAGS-y anywhere else (not sure if any are left by this point of the series) - sounds good. Jan
diff --git a/xen/Rules.mk b/xen/Rules.mk index c98d5372f3db..f0111f2bc1b4 100644 --- a/xen/Rules.mk +++ b/xen/Rules.mk @@ -39,6 +39,7 @@ ALL_OBJS-$(CONFIG_CRYPTO) += $(BASEDIR)/crypto/built_in.o # Initialise some variables CFLAGS_UBSAN := +ccflags-y := ifeq ($(CONFIG_DEBUG),y) CFLAGS += -O1 @@ -137,9 +138,13 @@ endif # Always build obj-bin files as binary even if they come from C source. $(obj-bin-y): CFLAGS := $(filter-out -flto,$(CFLAGS)) +# target with its suffix stripped +target-stem = $(basename $@) + c_flags = -MMD -MF $(@D)/.$(@F).d \ $(CFLAGS) \ - '-D__OBJECT_FILE__="$@"' + '-D__OBJECT_FILE__="$@"' \ + $(ccflags-y) $(CFLAGS_$(target-stem).o) a_flags = -MMD -MF $(@D)/.$(@F).d \ $(AFLAGS) diff --git a/xen/arch/arm/efi/Makefile b/xen/arch/arm/efi/Makefile index d34c9168914a..e4aaba3e074b 100644 --- a/xen/arch/arm/efi/Makefile +++ b/xen/arch/arm/efi/Makefile @@ -1,4 +1,4 @@ -CFLAGS += -fshort-wchar +ccflags-y += -fshort-wchar obj-y += boot.init.o runtime.o obj-$(CONFIG_ACPI) += efi-dom0.init.o diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile index 472e3fadb719..acf4c145c896 100644 --- a/xen/arch/x86/Makefile +++ b/xen/arch/x86/Makefile @@ -174,14 +174,14 @@ EFI_LDFLAGS += --major-subsystem-version=2 --minor-subsystem-version=0 export XEN_BUILD_EFI := $(shell $(CC) $(filter-out $(CFLAGS-y) .%.d,$(CFLAGS)) -c efi/check.c -o efi/check.o 2>/dev/null && echo y) # Check if the linker supports PE. XEN_BUILD_PE := $(if $(XEN_BUILD_EFI),$(shell $(LD) -mi386pep --subsystem=10 -o efi/check.efi efi/check.o 2>/dev/null && echo y)) -CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI +ccflags-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI $(TARGET).efi: VIRT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A VIRT_START$$,,p') $(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A ALT_START$$,,p') ifneq ($(build_id_linker),) ifeq ($(call ld-ver-build-id,$(LD) $(filter -m%,$(EFI_LDFLAGS))),y) -CFLAGS += -DBUILD_ID_EFI +ccflags-y += -DBUILD_ID_EFI EFI_LDFLAGS += $(build_id_linker) note_file := efi/buildid.o # NB: this must be the last input in the linker call, because inputs following @@ -227,7 +227,7 @@ efi/boot.init.o efi/runtime.o efi/compat.o efi/buildid.o efi/relocs-dummy.o: ; asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c $(BASEDIR)/include/asm-x86/asm-macros.h $(CC) $(filter-out -Wa$(comma)% -flto,$(c_flags)) -S -o $@ $< -asm-macros.i: CFLAGS += -D__ASSEMBLY__ -P +CFLAGS_asm-macros.o += -D__ASSEMBLY__ -P $(BASEDIR)/include/asm-x86/asm-macros.h: asm-macros.i Makefile echo '#if 0' >$@.new diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile index 4bc0a196e9ca..2cbb3de3a8ab 100644 --- a/xen/arch/x86/efi/Makefile +++ b/xen/arch/x86/efi/Makefile @@ -1,4 +1,4 @@ -CFLAGS += -fshort-wchar +ccflags-y += -fshort-wchar %.o: %.ihex $(OBJCOPY) -I ihex -O binary $< $@ diff --git a/xen/common/libelf/Makefile b/xen/common/libelf/Makefile index 3d9e38f27e65..9a433f01fbd4 100644 --- a/xen/common/libelf/Makefile +++ b/xen/common/libelf/Makefile @@ -3,7 +3,7 @@ nocov-y += libelf.o SECTIONS := text data $(SPECIAL_DATA_SECTIONS) -CFLAGS += -Wno-pointer-sign +ccflags-y += -Wno-pointer-sign libelf.o: libelf-temp.o Makefile $(OBJCOPY) $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@ diff --git a/xen/common/libfdt/Makefile b/xen/common/libfdt/Makefile index c075bbf5462a..9ea5c696d52a 100644 --- a/xen/common/libfdt/Makefile +++ b/xen/common/libfdt/Makefile @@ -5,7 +5,7 @@ SECTIONS := text data $(SPECIAL_DATA_SECTIONS) obj-y += libfdt.o nocov-y += libfdt.o -CFLAGS += -I$(BASEDIR)/include/xen/libfdt/ +ccflags-y += -I$(BASEDIR)/include/xen/libfdt/ libfdt.o: libfdt-temp.o Makefile $(OBJCOPY) $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@ diff --git a/xen/xsm/flask/Makefile b/xen/xsm/flask/Makefile index b1fd45421993..3bf0a6fa0456 100644 --- a/xen/xsm/flask/Makefile +++ b/xen/xsm/flask/Makefile @@ -4,7 +4,7 @@ obj-y += flask_op.o obj-y += ss/ -CFLAGS += -I./include +ccflags-y += -I./include AWK = awk diff --git a/xen/xsm/flask/ss/Makefile b/xen/xsm/flask/ss/Makefile index 046ce8f53326..30f910a9c9c1 100644 --- a/xen/xsm/flask/ss/Makefile +++ b/xen/xsm/flask/ss/Makefile @@ -8,4 +8,4 @@ obj-y += services.o obj-y += conditional.o obj-y += mls.o -CFLAGS += -I../include +ccflags-y += -I../include
We are going to want $(CFLAGS) to be static and never change during the build, so introduce new variables that can be use to change the flags of a single target or of a whole directory. Those two variables are taken from Kbuild, in Linux v5.4. Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> --- xen/Rules.mk | 7 ++++++- xen/arch/arm/efi/Makefile | 2 +- xen/arch/x86/Makefile | 6 +++--- xen/arch/x86/efi/Makefile | 2 +- xen/common/libelf/Makefile | 2 +- xen/common/libfdt/Makefile | 2 +- xen/xsm/flask/Makefile | 2 +- xen/xsm/flask/ss/Makefile | 2 +- 8 files changed, 15 insertions(+), 10 deletions(-)