| Message ID | 20160603100713.22378-1-Wei.Chen@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
(CC Ian) Hi, On 03/06/16 11:07, Wei Chen wrote: > When we update the header files that had been included in head.S. > The build system would not re-compile the head.S. Because in the > build rules, the dependencies are setting to .*.d (eg. DEPS = .*.d) > files in the same folder as Makefile. > > But head.S is very special, it was used by the Makefile in the parent > folder: "ALL_OBJS := $(TARGET_SUBARCH)/head.o". > > In this case, the build system could not find the dependency in DEPS. > When we update the header files, the build system is unware of this > update. If we re-build the Xen without doing make clean or touching > the head.S, the build system will not recompile the head.S. > > Signed-off-by: Wei Chen <Wei.Chen@linaro.org> > --- > In my mind, the better way to fix this bug is converting the DEPS from > ALL_OBJS. But I am afraid of the impact. I am not sure whether there > are some dependencies are not generated from obj files. My knowledge of the build system is limited. Stefano, Ian, Wei, could you give a look? Regards, > --- > xen/Rules.mk | 3 ++- > xen/arch/arm/Makefile | 2 ++ > 2 files changed, 4 insertions(+), 1 deletion(-) > > diff --git a/xen/Rules.mk b/xen/Rules.mk > index 961d533..1247b61 100644 > --- a/xen/Rules.mk > +++ b/xen/Rules.mk > @@ -92,9 +92,10 @@ LDFLAGS += $(LDFLAGS-y) > > include $(BASEDIR)/arch/$(TARGET_ARCH)/Rules.mk > > +DEPS = .*.d > + > include Makefile > > -DEPS = .*.d > define gendep > ifneq ($(1),$(subst /,:,$(1))) > DEPS += $(dir $(1)).$(notdir $(1)).d > diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile > index af4d0e1..9e38da3 100644 > --- a/xen/arch/arm/Makefile > +++ b/xen/arch/arm/Makefile > @@ -51,6 +51,8 @@ endif > > ALL_OBJS := $(TARGET_SUBARCH)/head.o $(ALL_OBJS) > > +DEPS += $(TARGET_SUBARCH)/.head.o.d > + > $(TARGET): $(TARGET)-syms $(TARGET).axf > $(OBJCOPY) -O binary -S $< $@ > ifeq ($(CONFIG_ARM_64),y) >
Julien Grall writes ("Re: [RFC] xen/arm: build: add missed dependency for head.S"):
> On 03/06/16 11:07, Wei Chen wrote:
> > When we update the header files that had been included in head.S.
> > The build system would not re-compile the head.S. Because in the
> > build rules, the dependencies are setting to .*.d (eg. DEPS = .*.d)
> > files in the same folder as Makefile.
> >
> > But head.S is very special, it was used by the Makefile in the parent
> > folder: "ALL_OBJS := $(TARGET_SUBARCH)/head.o".
> >
> > In this case, the build system could not find the dependency in DEPS.
> > When we update the header files, the build system is unware of this
> > update. If we re-build the Xen without doing make clean or touching
> > the head.S, the build system will not recompile the head.S.
> >
> > Signed-off-by: Wei Chen <Wei.Chen@linaro.org>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
This should be in 4.7 and is a backport candidate.
> > In my mind, the better way to fix this bug is converting the DEPS from
> > ALL_OBJS. But I am afraid of the impact. I am not sure whether there
> > are some dependencies are not generated from obj files.
I do like this idea but I have the same worry. It might be possible
to dump ALL_OBJS out somehow and check this, but it might be
arch-dependent.
Wei Chen's patch is IMO a straightforward fix.
Thanks,
Ian.
Hi Ian, On 07/06/16 11:03, Ian Jackson wrote: > Julien Grall writes ("Re: [RFC] xen/arm: build: add missed dependency for head.S"): >> On 03/06/16 11:07, Wei Chen wrote: >>> When we update the header files that had been included in head.S. >>> The build system would not re-compile the head.S. Because in the >>> build rules, the dependencies are setting to .*.d (eg. DEPS = .*.d) >>> files in the same folder as Makefile. >>> >>> But head.S is very special, it was used by the Makefile in the parent >>> folder: "ALL_OBJS := $(TARGET_SUBARCH)/head.o". >>> >>> In this case, the build system could not find the dependency in DEPS. >>> When we update the header files, the build system is unware of this >>> update. If we re-build the Xen without doing make clean or touching >>> the head.S, the build system will not recompile the head.S. >>> >>> Signed-off-by: Wei Chen <Wei.Chen@linaro.org> > > Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> > > This should be in 4.7 and is a backport candidate. Sounds good to me. >>> In my mind, the better way to fix this bug is converting the DEPS from >>> ALL_OBJS. But I am afraid of the impact. I am not sure whether there >>> are some dependencies are not generated from obj files. > > I do like this idea but I have the same worry. It might be possible > to dump ALL_OBJS out somehow and check this, but it might be > arch-dependent. FWIW, Wei sent a new version today [1] which implement his suggestion. Although it might be too risky for Xen 4.7. Regards, [1] http://lists.xenproject.org/archives/html/xen-devel/2016-06/msg00781.html
diff --git a/xen/Rules.mk b/xen/Rules.mk index 961d533..1247b61 100644 --- a/xen/Rules.mk +++ b/xen/Rules.mk @@ -92,9 +92,10 @@ LDFLAGS += $(LDFLAGS-y) include $(BASEDIR)/arch/$(TARGET_ARCH)/Rules.mk +DEPS = .*.d + include Makefile -DEPS = .*.d define gendep ifneq ($(1),$(subst /,:,$(1))) DEPS += $(dir $(1)).$(notdir $(1)).d diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile index af4d0e1..9e38da3 100644 --- a/xen/arch/arm/Makefile +++ b/xen/arch/arm/Makefile @@ -51,6 +51,8 @@ endif ALL_OBJS := $(TARGET_SUBARCH)/head.o $(ALL_OBJS) +DEPS += $(TARGET_SUBARCH)/.head.o.d + $(TARGET): $(TARGET)-syms $(TARGET).axf $(OBJCOPY) -O binary -S $< $@ ifeq ($(CONFIG_ARM_64),y)
When we update the header files that had been included in head.S. The build system would not re-compile the head.S. Because in the build rules, the dependencies are setting to .*.d (eg. DEPS = .*.d) files in the same folder as Makefile. But head.S is very special, it was used by the Makefile in the parent folder: "ALL_OBJS := $(TARGET_SUBARCH)/head.o". In this case, the build system could not find the dependency in DEPS. When we update the header files, the build system is unware of this update. If we re-build the Xen without doing make clean or touching the head.S, the build system will not recompile the head.S. Signed-off-by: Wei Chen <Wei.Chen@linaro.org> --- In my mind, the better way to fix this bug is converting the DEPS from ALL_OBJS. But I am afraid of the impact. I am not sure whether there are some dependencies are not generated from obj files. --- xen/Rules.mk | 3 ++- xen/arch/arm/Makefile | 2 ++ 2 files changed, 4 insertions(+), 1 deletion(-)