[v6,5/8] kbuild: add fine grained build dependencies for exported symbols

Message ID alpine.LFD.2.20.1603161050160.30579@knanqh.ubzr
State New
Headers show

Commit Message

Nicolas Pitre March 16, 2016, 3:05 p.m.
On Wed, 16 Mar 2016, Michal Marek wrote:

> On 2016-03-16 00:14, Nicolas Pitre wrote:

> > On Tue, 15 Mar 2016, Michal Marek wrote:

> > 

> >> Dne 14.3.2016 v 03:42 Nicolas Pitre napsal(a):

> >>> +# Filter out exported kernel symbol names from the preprocessor output.

> >>> +# See also __KSYM_DEPS__ in include/linux/export.h.

> >>> +# We disable the depfile generation here, so as not to overwrite the existing

> >>> +# depfile while fixdep is parsing it

> >>> +flags_nodeps = $(filter-out -Wp$(comma)-M%, $($(1)))

> >>> +ksym_dep_filter =                                                            \

> >>> +	case "$(1)" in                                                       \

> >>> +	cc_*_c) $(CPP) $(call flags_nodeps,c_flags) -D__KSYM_DEPS__ $< ;;    \

> >>> +	as_*_S) $(CPP) $(call flags_nodeps,a_flags) -D__KSYM_DEPS__ $< ;;    \

> >>> +	cpp_lds_S) : ;;                                                      \

> >>> +	*) echo "Don't know how to preprocess $(1)" >&2; false ;;            \

> >>> +	esac | sed -rn 's/^.*=== __KSYM_(.*) ===.*$$/KSYM_\1/p'

> >>> +

> >>> +cmd_and_fixdep =                                                             \

> >>> +	$(echo-cmd) $(cmd_$(1));                                             \

> >>> +	$(ksym_dep_filter) |                                                 \

> >>> +		scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)'          \

> >>> +			> $(dot-target).tmp;	                             \

> >>> +	rm -f $(depfile);                                                    \

> >>> +	mv -f $(dot-target).tmp $(dot-target).cmd;

> >>> +

> >>> +endif

> >>

> >> Not sure what happened this time, but I got

> >>

> >> drivers/md/.dm-round-robin.mod.o.cmd:5: *** unterminated call to

> >> function 'wildcard': missing ')'.  Stop.

> >>

> >> The depfile is indeed corrupt (truncated):

> >> tail drivers/md/.dm-round-robin.mod.o.cmd

> >>   arch/x86/include/asm/disabled-features.h \

> >>     $(wildcard include/config/x86/intel/mpx.h) \

> >>   arch/x86/include/asm/rmwcc.h \

> >>   arch/x86/include/asm/barrier.h \

> >>     $(wildcard include/config/x86/ppro/fence.h) \

> >>   arch/x86/include/asm/nops.h \

> >>     $(wildcard include/config/mk7.h) \

> >>   include/asm-generic/barrier.h \

> >>   include/asm-generic/bitops/find.h \

> >>     $(wildcard include/config/generic/

> >>

> >> The file is exactly 8kB long:

> >> $ ls -l drivers/md/.dm-round-robin.mod.o.cmd

> >> -rw-r--r-- 1 mmarek users 8192 Mar  8 13:33

> >> drivers/md/.dm-round-robin.mod.o.cmd

> > 

> > [...]

> > 

> >> Forgot to add: This was an allmodconfig build without

> >> CONFIG_TRIM_UNUSED_SYMS.

> > 

> > If CONFIG_TRIM_UNUSED_SYMS is actually not selected, then I really don't 

> > see how my changes can be involved in this failure.

> 

> I have no idea either.

> 

> 

> > And I cannot reproduce here so far. I didn't receive anything from 

> > kbuild test robot since February 15 either. Is this something that you 

> > are able to reproduce on your side?

> 

> I started a build loop now.

> 

> 

> > If so, do you get suspicious output on stderr during the build?  Maybe 

> > fixdep exits prematurelywith "fixdep: bad data on stdin"?  However, that 

> > cannot happen if CONFIG_TRIM_UNUSED_SYMS=n.

> > 

> > Did you test my git branch, or did you apply the posted patches to your 

> > tree?  If the later, could you publish a branch for it so I could test 

> > the same tree as you do?

> 

> I applied the patches to my -rc1 based kbuild branch and yes, there was

> a conflict with 2aedcd098a94 ("kbuild: suppress annoying "... is up to

> date." message"). So it's possible that I screwed it up. I pushed the

> branch to

> 

> git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild.git

> tmp.autoksyms6


As far as I can see, the conflict resolution is correct.

Testing your branch now. No failure so far.

I did notice spurious error messages after cleaning my build tree.  
They're unrelated to your failure case though. Regardless, here's a 
patch to silence them.

----- >8
From: Nicolas Pitre <nicolas.pitre@linaro.org>

Subject: kbuild: don't complain about existing if_changed_dep targets

There are more if_changed_dep cases for which we know there is no
ksyms to parse. Add them to the list.

Also add a full stop to the comment.

Signed-off-by: Nicolas Pitre <nico@linaro.org>

Patch

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index f8631a935e..a09927e027 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -271,13 +271,13 @@  else
 # Filter out exported kernel symbol names from the preprocessor output.
 # See also __KSYM_DEPS__ in include/linux/export.h.
 # We disable the depfile generation here, so as not to overwrite the existing
-# depfile while fixdep is parsing it
+# depfile while fixdep is parsing it.
 flags_nodeps = $(filter-out -Wp$(comma)-M%, $($(1)))
 ksym_dep_filter =                                                            \
 	case "$(1)" in                                                       \
 	cc_*_c) $(CPP) $(call flags_nodeps,c_flags) -D__KSYM_DEPS__ $< ;;    \
 	as_*_S) $(CPP) $(call flags_nodeps,a_flags) -D__KSYM_DEPS__ $< ;;    \
-	cpp_lds_S) : ;;                                                      \
+	boot*|build*|*cpp_lds_S|dtc|host*|vdso*) : ;;                        \
 	*) echo "Don't know how to preprocess $(1)" >&2; false ;;            \
 	esac | sed -rn 's/^.*=== __KSYM_(.*) ===.*$$/KSYM_\1/p'