On Tue, Mar 18, 2014 at 06:27:48 -0600, Eric Blake wrote:
On 03/18/2014 05:00 AM, Jiri Denemark wrote:
Why don't we just avoid the whole issue by removing use of abs_srcdir and abs_builddir. Can this rule:
$(abs_builddir)/cpu/cpu_map.xml: $(AM_V_GEN)ln -s $(abs_srcdir)/cpu/cpu_map.xml $@
be just changed to
cpu/cpu_map.xml: $(AM_V_GEN)ln -s $(srcdir)/cpu/cpu_map.xml $@
That's what I tried first but it does not work at all. I don't understand why but make thinks cpu/cpu_map.xml target is uptodate even though the file does not exist in builddir.
That would be VPATH rewriting at play. Does $(builddir)/cpu/cpu_map.xml fare any better?
No, that doesn't work either. ...
But maybe that's some food for thought - instead of having a rule that uses a direct file name, perhaps you can instead have a witness rule on a stamp file name, where we write the link ourselves when needed, and then have all dependencies be on the stamp (which will ALWAYS exist only in builddir):
cpu/cpu_map.xml.stamp: $(AM_V_GEN)if test -f cpu/cpu_map.xml; then \ :; else \ ln -s `cd $(srcdir) && pwd`/cpu/cpu_map.xml \ cpu/cpu_map.xml; \ fi && touch $@
OK, this seems to work. It's uglier and doesn't regenerate the link if someone removes it (the *.stamp file would need to be removed too) but if that's considered a better way compared to setting abs_*dir, I can make a proper patch out of it after testing it in all situations. Jirka