Re: ccache, MSVC, and meson

On Tue, May 24, 2022 at 01:30:39PM -0700, Andres Freund wrote:
> On 2022-05-24 14:52:02 -0500, Justin Pryzby wrote:
> > > The spurious message should be fixed, of course. I suspect you dont need a
> > > wrapper, you can just set CC='ccache cl.exe' or similar? Afaics it's not
> > > meaningful to do 'CC=ccache.exe' alone, because then it'll interpret arguments
> > > as ccache options, rather than compiler options.
> > 
> > if meson didn't crash CC=ccache.exe might have worked, because I had set
> > CCACHE_COMPILER.
> 
> Did you report the issue? Should be simple enough to fix.
> 
> I seriously doubt it's a good idea to use CCACHE_COMPILER - there's no way
> meson (or autoconf or ..) can rely on the results of compiler tests that way,
> since CCACHE_COMPILER can change at any time.

This updated patch doesn't use CCACHE_COMPILER.

cache misses are several times slower (12 minute build time vs 2:30 with ninja,
without ccache), so it's possible that can be *slower* if the hit ratio is
inadequate.  ninja on cirrus builds 3x faster with ccache, but msbuild is only
~2x faster, so I recommend using it only with ninja.

There's still warts requires using "plain" with /Z7 /MDd.