RFR 8203838: javac performance regression in 11+11

[Maurizio Cimadamore]

Related issues:

[1] - https://bugs.openjdk.java.net/browse/JDK-8202157

[2] - https://bugs.openjdk.java.net/browse/JDK-8201281

Maurizio


On 15/06/18 19:05, Maurizio Cimadamore wrote:
> Hi,
> this patch fixes a performance regression that has been picked up by 
> our internal test runs. Vicente did a great job at fixing some of the 
> excessive exception sharing that takes place in the compiler, as part 
> of [1], [2]. However, there's a very hot execution path 
> (Resolve::reportMC) in which we can't affort allocating a new 
> exception every time a method check fails.
>
> This patch reintroduce some flyweight pattern for that particular case 
> only (along with some documentation which explains the hack :-)).
>
> Webrev here:
>
> http://cr.openjdk.java.net/~mcimadamore/8203838/
>
> Cheers
> Maurizio
>
>