[jdk25u] RFR: 8357289: Break down the String constructor into smaller methods

[Shaojin Wen]

Through JVM Option +PrintInlining, we found that String has a constructor codeSize of 852, which is too large. This caused failed to inline.

The following is the output information of PrintInlining:

                @ 9   java.lang.String::<init> (12 bytes)   inline (hot)
!m                 @ 1   java.nio.charset.Charset::defaultCharset (52 bytes)   inline (hot)
!                  @ 8   java.lang.String::<init> (852 bytes)   failed to inline: hot method too big


In Java code, the big method that cannot be inlined is the following constructor


String(Charset charset, byte[] bytes, int offset, int length) {}

The above String constructor is too large; break it down into smaller methods with a codeSize under 325 to allow them to be inlined by the C2.

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Commit messages:
 - 8357289: Break down the String constructor into smaller methods

Changes: https://git.openjdk.org/jdk25u/pull/351/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=351&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357289
  Stats: 181 lines in 1 file changed: 62 ins; 79 del; 40 mod
  Patch: https://git.openjdk.org/jdk25u/pull/351.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/351/head:pull/351

PR: https://git.openjdk.org/jdk25u/pull/351