RFR: 8340544: Optimize setLocalsFromArg [v2]

[Claes Redestad]

On Fri, 20 Sep 2024 16:35:05 GMT, Shaojin Wen <swen at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/classfile/impl/StackMapGenerator.java line 1069:
>> 
>>> 1067:                     localsSize += 2;
>>> 1068:                 } else {
>>> 1069:                     if (desc == CD_int || desc == CD_boolean || desc == CD_byte || desc == CD_char || desc == CD_short) {
>> 
>> An alternative would be `if (!desc.isPrimitive()) { .. } else if (desc == CD_float) { .. } else { /* INTEGER_TYPE */ }` - might be more compact at least.
>
> because ClassDesc permits PrimitiveClassDescImpl & ReferenceClassDescImpl, based on @cl4es 's suggestion, I used `instanceof ReferenceClassDescImpl` instead of `!isPrimitive()`, and now codeSize becomes 239

Great! Yeah, overrides of `isPrimitive` would probably be overall better than the current default method.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21106#discussion_r1768935058