Re: [patch/rfc] Generate makefile dependencies

Andrew Cagney
2004-03-11T17:23:42Z

>> Er, that's a postive - the dependency list is guarenteed to always match the shipped source.
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> Might be too big a step, depending on how expensive it is.
> I think this has been experimented with before, and was abandoned
> because there are a lot of header files on which -everything- depends.
> If the makefile dependencies are -too- correct, then touching any
> of those files causes everything to rebuild. Sometimes you want
> that -- but sometimes you don't.

The oposite is true. Per:

> # "system" headers. Using these in dependencies is a rather personal
> # choice. (-rich, summer 1993)
> # (Why would we not want to depend on them? If one of these changes in a
> # non-binary-compatible way, it is a real pain to remake the right stuff
> # without these dependencies -kingdon, 13 Mar 1994)

People have always tried to keep the dependencies correct (but have
unfortunatly had to do it by hand). With 6.0 the dependencies were
checked and updated mechanically, and with this patch that mechanism
becomes the default. No longer a need to hand generate this stuff.

Andrew

> Can I suggest maybe having a separate make target for
> generating the dependencies? And maybe a second one for
> reverting them? Then you could choose when to do it.

>>> It's like regenerating configure; we try not to run
>>> autoconf during the build process, and not just because autoconf is so
>>> finicky.
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>> Andrew
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