String concatenation tweaks

Maurizio Cimadamore maurizio.cimadamore at
Thu Jun 4 12:35:13 UTC 2015

On 04/06/15 13:12, Aleksey Shipilev wrote:
> On 06/04/2015 03:01 PM, Maurizio Cimadamore wrote:
>> One more question. I guess baseline is vanilla javac, while all the
>> others are using indy (as you explain in your notes very well). How
>> about also running a benchmark with the original patch proposed in this
>> thread, which doesn't do indy, but only precomputes sizes where possible?
> Yes, the baseline is vanilla javac.
> I don't think Louis had provided a patch, but just described what is
> being done there, and then asking if he should prepare the patch. I
> think it would be better to let Louis et al. forward-port their javac
> changes to StringConcatFactory -- that would be the improvement for our
> (quite naive) concat translation strategies. This JEP is about letting
> the development happen without messing with javac all the time :)
Well, yes - but adding a new indy is not something that comes for free. 
We are currently fighting to get specialization to work correctly with 
lambdas, and it turns out that having an indy, as Brian said, is like 
having an entirely new bytecode - so, for every new 'officially 
supported' bootstrap that we add, we will need to find ways to make that 
work with whatever new feature XYZ we could come up in the future.

So, my question remains: how much of that speedup can be obtained w/o 
indy? I think that's a fair question for the JEP you are filing.

> Thanks,
> -Aleksey.

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