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 190:

> 188:     write_byte_impl(bit1 | (next & 0x7f));
> 189:     next >>= 7;
> 190:   }

Could you please document the encoding/decoding schema in comments to the class? Could you also please include examples?
Why is it chosen to split 32 bits into 6, 7, 7, 7 and 5?

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