<i18n dev> RFR: 8365186: Reduce size of j.t.f.DateTimePrintContext::adjust

[Stephen Colebourne]

On Tue, 5 Aug 2025 01:23:17 GMT, Shaojin Wen <swen at openjdk.org> wrote:

> By adding the JVM startup parameters `-XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining` and analyzing the printed log information, and found that the code size of the j.t.f.DateTimePrintContext::adjust method is 382, which is greater than 325, causing inlining failure.
> 
> 
> @ 7   java.time.format.DateTimePrintContext::adjust (382 bytes)   failed to inline: hot method too big
> 
> 
> By splitting the code into `common/uncommon`, and moving the uncommon code into adjust0, the adjust method is kept small and can be inlined by the C2 optimizer.

src/java.base/share/classes/java/time/format/DateTimePrintContext.java line 152:

> 150:                 return chrono.zonedDateTime(Instant.from(temporal), overrideZone);
> 151:             }
> 152:         }

Have you tested the split at different locations? I would expect line 143 or line 130 to perform best. There may be a case for splitting multiple times. You will also need a comment to indicate why the method is split.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26633#discussion_r2256531178