On Sat, 20 Apr 2024 00:00:54 GMT, ExE Boss <d...@openjdk.org> wrote:
>> We can reduce overhead of first use of a switch bootstrap by moving
>> `typePairToName` into `TypePairs` and by explicitly overriding `hashCode`
>> and `equals`. The first change avoids loading and initializing the
>> `TypePairs` class in actual cases, the second remove some excess code
>> generation from happening on first use.
>
> src/java.base/share/classes/java/lang/runtime/SwitchBootstraps.java line 685:
>
>> 683: record TypePairs(Class<?> from, Class<?> to) {
>> 684:
>> 685: private static final Map<TypePairs, String> typePairToName =
>> initialize();
>
> If `TypePairs.typePairToName` is never modified after initialisation, then it
> should probably be made immutable:
> Suggestion:
>
> private static final Map<TypePairs, String> typePairToName =
> Map.copyOf(initialize());
If you really think about it, the `initialize` method itself is somewhat
problematic, as it's initializing with byte/short/char on the left, all of
which are already converted to int in the of() factory. This should be done in
a separate issue.
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PR Review Comment: https://git.openjdk.org/jdk/pull/18865#discussion_r1573195851
