Profiling compilation time
Yang Zhang
yanghatespam@gmail.com
Tue Mar 24 19:27:00 GMT 2009
Ian Lance Taylor wrote:
> Yang Zhang <yanghatespam@gmail.com> writes:
>
>> Ian Lance Taylor wrote:
>>> Use the -ftime-report option.
>> Neat! Is there something similar for breaking down the time into time
>> spent on individual files so that I can see which #included files are
>> the most costly? (If you treat the compiler as a template language
>> interpreter then you can even imagine getting call-graph profiling
>> results.)
>
> That's a good idea. Unfortunately, I don't think there is anything like
> that at present. It would be hard, and perhaps meaningless, to do that
> for the IPA passes, but it could be done for the frontends and for the
> general optimization passes (where I suppose the time for inlined
> functions would go the function into which they are inlined.)
>
> Ian
For me, -ftime-report shows that compilation time is by far dominated by
parsing, so that's what I'm most interested in. To that end, would a
valid poor man's profiling approach be to simply measure the time of
#including individual files into an otherwise empty source file? Or
would it be necessary to actually "trigger" the parsing somehow by using
the headers' contents (particularly for templated entities)?
--
Yang Zhang
http://www.mit.edu/~y_z/
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