Andreas Schwab and Russel King noted some problems with my
first patch for the modversions.h problem: it wouldn't work
with parallel makes (due to assuming make executes dependencies
left-to-right), and it could cause excessive recompilations
(due to always updating modversions.h).
Here's Version 2 of the patch which I think addresses
all of the issues raised. In particular:
- sequencing is expressed by shell commands
- update-modverfile does the update via a temporary file,
and only touches modversions.h if it actually changed
This version has survived numerous 'make -j dep' on UP.
I didn't use a .PHONY: on modversions.h as Russel suggested,
since that would cause re-execution of that rule whenever a
target depends on modversions.h via some .{h,}depend file.
A question: Rules.make has a goal 'dep' which does the same
thing as 'fastdep', however, 'fastdep' is what the top-level
Makefile's 'dep' invokes. What's Rules.make's 'dep' for?
/Mikael
--- linux-2.4.0-test5-pre6/Makefile.~1~ Thu Jul 27 21:36:59 2000
+++ linux-2.4.0-test5-pre6/Makefile Thu Jul 27 21:37:24 2000
@@ -437,6 +437,9 @@
scripts/mkdep init/*.c > .depend
scripts/mkdep `find $(FINDHPATH) -name SCCS -prune -o -follow -name \*.h ! -name modversions.h -print` > .hdepend
$(MAKE) $(patsubst %,_sfdep_%,$(SUBDIRS)) _FASTDEP_ALL_SUB_DIRS="$(SUBDIRS)"
+ifdef CONFIG_MODVERSIONS
+ $(MAKE) update-modverfile
+endif
ifdef CONFIG_MODVERSIONS
MODVERFILE := $(TOPDIR)/include/linux/modversions.h
@@ -445,7 +448,7 @@
endif
export MODVERFILE
-depend dep: dep-files $(MODVERFILE)
+depend dep: dep-files
# make checkconfig: Prune 'scripts' directory to avoid "false positives".
checkconfig:
--- linux-2.4.0-test5-pre6/Rules.make.~1~ Sat Jul 1 00:13:51 2000
+++ linux-2.4.0-test5-pre6/Rules.make Thu Jul 27 22:46:54 2000
@@ -215,8 +215,16 @@
$(addprefix $(MODINCL)/,$(SYMTAB_OBJS:.o=.ver)): $(TOPDIR)/include/linux/autoconf.h
-$(TOPDIR)/include/linux/modversions.h: $(addprefix $(MODINCL)/,$(SYMTAB_OBJS:.o=.ver))
- @echo updating $(TOPDIR)/include/linux/modversions.h
+# updates .ver files but not modversions.h
+fastdep: $(addprefix $(MODINCL)/,$(SYMTAB_OBJS:.o=.ver))
+
+# updates .ver files and modversions.h like before (is this needed?)
+dep: fastdep update-modverfile
+
+endif # SYMTAB_OBJS
+
+# update modversions.h, but only if it would change
+update-modverfile:
@(echo "#ifndef _LINUX_MODVERSIONS_H";\
echo "#define _LINUX_MODVERSIONS_H"; \
echo "#include <linux/modsetver.h>"; \
@@ -225,11 +233,14 @@
if [ -f $$f ]; then echo "#include <linux/modules/$${f}>"; fi; \
done; \
echo "#endif"; \
- ) > $@
-
-dep fastdep: $(TOPDIR)/include/linux/modversions.h
-
-endif # SYMTAB_OBJS
+ ) > $(TOPDIR)/include/linux/modversions.h.tmp
+ @if [ -r $(TOPDIR)/include/linux/modversions.h ] && cmp -s $(TOPDIR)/include/linux/modversions.h $(TOPDIR)/include/linux/modversions.h.tmp; then \
+ echo $(TOPDIR)/include/linux/modversions.h was not updated; \
+ rm -f $(TOPDIR)/include/linux/modversions.h.tmp; \
+ else \
+ echo $(TOPDIR)/include/linux/modversions.h was updated; \
+ mv -f $(TOPDIR)/include/linux/modversions.h.tmp $(TOPDIR)/include/linux/modversions.h; \
+ fi
$(M_OBJS): $(TOPDIR)/include/linux/modversions.h
ifdef MAKING_MODULES
-
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