Re: ccache support for make buildworld/make release

On Wed, Aug 25, 2004 at 08:01:31PM -0700, Kris Kennaway wrote:
> On Thu, Aug 26, 2004 at 12:01:44AM +0300, Ruslan Ermilov wrote:
> > On Wed, Aug 25, 2004 at 11:51:57PM +0300, Maxim Sobolev wrote:
> > > Yeah, I've noticed that as well. Also, for some reason when I've re-run 
> > > make world second time all objects built after buildtools miss the 
> > > cache. Strange....
> > > 
> > Does ccache take into account that the "cc" binary may be different
> > for the same source and the command?  What will happen, assuming
> > it's made to work, if you attempt to build the native i386 world,
> > and then try to "make buildworld TARGET_ARCH=alpha"?  The cc
> > command will be the same; will ccache substitute the i386 code in
> > this case?  Also, what happens for a native build when we upgrade
> > GCC version in the base?
> 
> I believe it hashes the output of the preprocessor and uses that as
> the index into the cache.  So cross-builds should probably be fine
> (assuming the right cc is used) since they'll hash differently.
> Compiler upgrades might not work reliably since you might sometimes
> get the object file from the old compiler.
> 
I'm pretty sure the following code will preprocess identically on
all architectures, no?

: void
: foo(void)
: {
: }


Cheers,
-- 
Ruslan Ermilov
ru_at_FreeBSD.org
FreeBSD committer