diff options
Diffstat (limited to 'depsver.mf')
| -rw-r--r-- | depsver.mf | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/depsver.mf b/depsver.mf new file mode 100644 index 000000000000..3e4a6185a13c --- /dev/null +++ b/depsver.mf @@ -0,0 +1,67 @@ +$(DEPDIR)/deps-ver: $(top_srcdir)/deps-ver + @[ -f $@ ] || \ + cp $(top_srcdir)/deps-ver $@ + @[ -w $@ ] || \ + chmod ug+w $@ + @cmp $(top_srcdir)/deps-ver $@ > /dev/null || ( \ + $(MAKE) clean && \ + echo -n "Prior $(subdir)/$(DEPDIR) version " && \ + cat $@ && \ + rm -rf $(DEPDIR) && \ + mkdir $(DEPDIR) && \ + case "$(top_builddir)" in \ + .) \ + ./config.status Makefile depfiles \ + ;; \ + ..) \ + cd .. && \ + ./config.status $(subdir)/Makefile depfiles && \ + cd $(subdir) \ + ;; \ + *) \ + echo 'Fatal: depsver.mf Automake fragment limited' \ + 'to immediate subdirectories.' && \ + echo "top_builddir: $(top_builddir)" && \ + echo "subdir: $(subdir)" && \ + exit 1 \ + ;; \ + esac && \ + echo -n "Cleaned $(subdir)/$(DEPDIR) version " && \ + cat $(top_srcdir)/deps-ver \ + ) + cp $(top_srcdir)/deps-ver $@ + +.deps-ver: $(top_srcdir)/deps-ver + @[ ! -d $(DEPDIR) ] || $(MAKE) $(DEPDIR)/deps-ver + @touch $@ + +BUILT_SOURCES += .deps-ver +CLEANFILES += .deps-ver + +# +# depsver.mf included in Makefile.am for directories with .deps +# +# When building in the same directory with sources that change over +# time, such as when tracking using bk, the .deps files can become +# stale with respect to moved, deleted, or superceded headers. Most +# commonly, this would exhibit as make reporting a failure to make a +# header file which is no longer in the location given. To address +# this issue, we use a deps-ver file which is updated with each change +# that breaks old .deps files. A copy of deps-ver is made into +# $(DEPDIR) if not already present. If $(DEPDIR)/deps-ver is present +# with different contents than deps-ver, we make clean to ensure all +# .o files built before the incompatible change are rebuilt along with +# their updated .deps files, then remove $(DEPDIR) and recreate it as +# empty stubs. +# +# It is normal when configured with --disable-dependency-tracking for +# the DEPDIR to not have been created. For this reason, we use the +# intermediate target .deps-ver, which invokes make recursively if +# DEPDIR exists. +# +# If you modify depsver.mf, please make the changes to the master +# copy, the one in sntp is copied by the bootstrap script from it. +# +# This comment block follows rather than leads the related code so that +# it stays with it in the generated Makefile.in and Makefile. +# |