On Mon, 13 Mar 2023 18:51:17 GMT, Frederic Parain <fpar...@openjdk.org> wrote:

>> Please review this change re-implementing the FieldInfo data structure.
>> 
>> The FieldInfo array is an old data structure storing fields metadata. It has 
>> poor extension capabilities, a complex management code because of lack of 
>> strong typing and semantic overloading, and a poor memory efficiency.
>> 
>> The new implementation uses a compressed stream to store those metadata, 
>> achieving better memory density and providing flexible extensibility, while 
>> exposing a strongly typed set of data when uncompressed. The stream is 
>> compressed using the unsigned5 encoding, which alreay present in the JDK 
>> (because of pack200) and the JVM (because JIT compulers use it to comrpess 
>> debugging information).
>> 
>> More technical details are available in the CR: 
>> https://bugs.openjdk.org/browse/JDK-8292818
>> 
>> Those changes include a re-organisation of fields' flags, splitting the 
>> previous heterogeneous AccessFlags field into three distincts flag 
>> categories: immutable flags from the class file, immutable fields defined by 
>> the JVM, and finally mutable flags defined by the JVM.
>> 
>> The SA, CI, and JVMCI, which all used to access the old FieldInfo array, 
>> have been updated too to deal with the new FieldInfo format.
>> 
>> Tested with mach5, tier 1 to 7.
>> 
>> Thank you.
>
> Frederic Parain has updated the pull request incrementally with one 
> additional commit since the last revision:
> 
>   Fixes includes and style

All my comments are addressed. Thank you! This is significant work.

-------------

Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12855

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