[ccache] Why not cache link commands?
ams at codesourcery.com
Tue Sep 18 09:27:21 MDT 2012
On 18/09/12 15:31, Justin Lebar wrote:
>> So, again, before I waste my time implementing this feature, are there any
>> other fundamental gotchas that would prevent it ever working or ever being
> On a large project with many inputs to ld, you'd have to hash a /lot/
> of object files, increasing the overhead of ccache substantially. I
> understand that this isn't your particular use-case, but it's the
> common one.
Yes, that's true, but those are also the most expensive link commands,
so maybe it's not so bad.
I realise that there's some risk that a cache miss can be expensive, and
that a cache hit might be only a very little cheaper than the real link,
but I'm prepared to take that risk. What I'm looking for is more
concrete roadblocks I haven't considered.
Incidentally, I'm also considering the possibility of caching the hashes
and using the inode/size/mtime etc. to short-cut that process (perhaps
as a "sloppiness" option), not only for objects, but also for sources.
> If you're on Linux, have you tried the gold linker?
Let's limit this discussion to what can be done with ccache, please. I
assure you, we know about the toolchain options.
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