Separate SyntheticEvent constructors to prevent deopts #19907
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Debugging the Flow fix is gonna be fun given Flow is broken for me locally. Sigh. |
trueadm
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Sep 25, 2020
koto
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Jun 15, 2021
* Remove arguments from hot path * Make SyntheticEvent subtypes monomorphic * Maybe fix Flow?
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Builds on #19906. (Well, really, replaces it.)
I suspect that I introduced a regression way back in #19433 when I removed the
SyntheticEvent.extendhelper. I'm not 100% sure but I think that as a result of going through differentInterfaces in the same function instance, the singleSyntheticEventconstructor has become megamorphic (because we'd set different fields in different order onthis). It is a very hot path (and even more so with the eager change) so I'm splitting these into separate function instances.With this change, I'm consistently seeing ~20% less time spent inside the constructor on average.