RFR: 8293170: Improve encoding of the debuginfo nmethod section

[Doug Simon]

On Thu, 25 Aug 2022 14:35:32 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

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/code/CompressedSparceDataReadStream.java line 28:

> 26: import sun.jvm.hotspot.debugger.*;
> 27: 
> 28: public class CompressedSparceDataReadStream extends CompressedReadStream {

CompressedSparceDataReadStream -> CompressedSparseDataReadStream

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