RFR: 8293170: Improve encoding of the debuginfo nmethod section [v5]

[Evgeny Astigeevich]

On Thu, 13 Oct 2022 09:42:54 GMT, Boris Ulasevich <bulasevich at openjdk.org> wrote:

>> The nmethod "scopes data" section is 10% of the size of nmethod. Now the data is compressed using the Pack200 algorithm, which is good for encoding small integers (LineNumberTable, etc). Using the fact that half of the data in the partition contains zeros, I reduce its size by another 30%.
>>  
>> Testing: jtreg hotspot&jdk, Renaissance benchmarks
>
> Boris Ulasevich has updated the pull request incrementally with one additional commit since the last revision:
> 
>   cleanup and rename

src/hotspot/share/code/compressedStream.cpp line 182:

> 180:     return;
> 181:   }
> 182:   int bit0 = 0x80; // first byte upper bit is set to indicate a value is not zero

This is untraditional and confusing. In a byte we are preparing it is bit 7. The same comment is about `bit1`.

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PR: https://git.openjdk.org/jdk/pull/10025