| Message ID | bb246053-f49b-58af-5381-fe0674f645de@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | build: fix dependency tracking for preprocessed files | expand |
On 04/06/2020 11:22, Jan Beulich wrote: > While the issue is more general, I noticed that asm-macros.i not getting > re-generated as needed. This was due to its .*.d file mentioning > asm-macros.o instead of asm-macros.i. Use -MQ here as well, and while at > it also use -MQ to avoid the somewhat fragile sed-ary on the *.lds > dependency tracking files. While there, further avoid open-coding $(CPP) > and drop the bogus -Ui386. Its not bogus. It really is needed to prevent OUTPUT_ARCH(i386:x86-64) being preprocessed to OUTPUT_ARCH(1:x86-64) This explodes properly with 32bit builds, but we might get away with it now on a 64bit build (preprocessing without -m32 does appear to skip this transformation). However, the robust way to deal with it is: /* Don't clobber the ld directive */ #undef i386 unconditionally in xen.lds.S > Signed-off-by: Jan Beulich <jbeulich@suse.com> > > --- a/xen/Rules.mk > +++ b/xen/Rules.mk > @@ -201,13 +201,13 @@ $(filter %.init.o,$(obj-y) $(obj-bin-y) > $(call if_changed,obj_init_o) > > quiet_cmd_cpp_i_c = CPP $@ > -cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ > +cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ -MQ $@ Please can -MQ come before $<, so the input and output files are still at the end of the command. It is a very useful property of the current setup, when playing build system surgery. If you're happy with both of these suggestions, Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> to save another round trip. Alternatively, I'm happy to submit the i386 as a prereq patch, seeing as it isn't now such a trivial change any more. ~Andrew
On 04.06.2020 13:35, Andrew Cooper wrote: > On 04/06/2020 11:22, Jan Beulich wrote: >> While the issue is more general, I noticed that asm-macros.i not getting >> re-generated as needed. This was due to its .*.d file mentioning >> asm-macros.o instead of asm-macros.i. Use -MQ here as well, and while at >> it also use -MQ to avoid the somewhat fragile sed-ary on the *.lds >> dependency tracking files. While there, further avoid open-coding $(CPP) >> and drop the bogus -Ui386. > > Its not bogus. It really is needed to prevent OUTPUT_ARCH(i386:x86-64) > being preprocessed to OUTPUT_ARCH(1:x86-64) > > This explodes properly with 32bit builds, but we might get away with it > now on a 64bit build (preprocessing without -m32 does appear to skip > this transformation). We haven't been doing 32-bit builds for quite a while, hence I continue to assert the -U option is bogus; I'm not claiming it always has been (that's true just for Arm). > However, the robust way to deal with it is: > > /* Don't clobber the ld directive */ > #undef i386 > > unconditionally in xen.lds.S This would mean to add code with no effect, which I'd prefer to avoid. >> --- a/xen/Rules.mk >> +++ b/xen/Rules.mk >> @@ -201,13 +201,13 @@ $(filter %.init.o,$(obj-y) $(obj-bin-y) >> $(call if_changed,obj_init_o) >> >> quiet_cmd_cpp_i_c = CPP $@ >> -cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ >> +cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ -MQ $@ > > Please can -MQ come before $<, so the input and output files are still > at the end of the command. It is a very useful property of the current > setup, when playing build system surgery. Ah yes, but then I'll make it " -MQ $@ -o $@ $<", better matching the .lds rules (where I'll also move -MQ ahead of -o). > If you're happy with both of these suggestions, Reviewed-by: Andrew > Cooper <andrew.cooper3@citrix.com> to save another round trip. As per above, only the latter, so for now I won't put it into the patch. > Alternatively, I'm happy to submit the i386 as a prereq patch, seeing as > it isn't now such a trivial change any more. As per above, I don't think such an adjustment is wanted or needed. Jan
--- a/xen/Rules.mk +++ b/xen/Rules.mk @@ -201,13 +201,13 @@ $(filter %.init.o,$(obj-y) $(obj-bin-y) $(call if_changed,obj_init_o) quiet_cmd_cpp_i_c = CPP $@ -cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ +cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@ -MQ $@ quiet_cmd_cc_s_c = CC $@ cmd_cc_s_c = $(CC) $(filter-out -Wa$(comma)%,$(c_flags)) -S $< -o $@ quiet_cmd_s_S = CPP $@ -cmd_s_S = $(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) $< -o $@ +cmd_s_S = $(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) $< -o $@ -MQ $@ %.i: %.c FORCE $(call if_changed,cpp_i_c) --- a/xen/arch/arm/Makefile +++ b/xen/arch/arm/Makefile @@ -123,9 +123,7 @@ asm-offsets.s: $(TARGET_SUBARCH)/asm-off $(CC) $(filter-out -flto,$(c_flags)) -S -o $@ $< xen.lds: xen.lds.S - $(CC) -P -E -Ui386 $(a_flags) -o $@ $< - sed -e 's/xen\.lds\.o:/xen\.lds:/g' <.xen.lds.d >.xen.lds.d.new - mv -f .xen.lds.d.new .xen.lds.d + $(CPP) -P $(a_flags) -o $@ -MQ $@ $< dtb.o: $(CONFIG_DTB_FILE) --- a/xen/arch/x86/Makefile +++ b/xen/arch/x86/Makefile @@ -244,9 +244,7 @@ $(BASEDIR)/include/asm-x86/asm-macros.h: efi.lds: AFLAGS-y += -DEFI xen.lds efi.lds: xen.lds.S - $(CC) -P -E -Ui386 $(filter-out -Wa$(comma)%,$(a_flags)) -o $@ $< - sed -e 's/.*\.lds\.o:/$(@F):/g' <.$(@F).d >.$(@F).d.new - mv -f .$(@F).d.new .$(@F).d + $(CPP) -P $(filter-out -Wa$(comma)%,$(a_flags)) -o $@ -MQ $@ $< boot/mkelf32: boot/mkelf32.c $(HOSTCC) $(HOSTCFLAGS) -o $@ $<
While the issue is more general, I noticed that asm-macros.i not getting re-generated as needed. This was due to its .*.d file mentioning asm-macros.o instead of asm-macros.i. Use -MQ here as well, and while at it also use -MQ to avoid the somewhat fragile sed-ary on the *.lds dependency tracking files. While there, further avoid open-coding $(CPP) and drop the bogus -Ui386. Signed-off-by: Jan Beulich <jbeulich@suse.com>