On Wed, 25 May 2022 00:35:24 GMT, Joe Darcy <da...@openjdk.org> wrote:

>> This is an early review of changes to better model JVM access flags, that is 
>> "modifiers" like public, protected, etc. but explicitly at a VM level.
>> Language level modifiers and JVM level access flags are closely related, but 
>> distinct. There are concepts that overlap in the two domains (public, 
>> private, etc.), others that only have a language-level modifier (sealed), 
>> and still others that only have an access flag (synthetic).
>> The existing java.lang.reflect.Modifier class is inadequate to model these 
>> subtleties. For example, the bit positions used by access flags on different 
>> kinds of elements overlap (such as "volatile" for fields and "bridge" for 
>> methods. Just having a raw integer does not provide sufficient context to 
>> decode the corresponding language-level string. Methods like 
>> Modifier.methodModifiers() were introduced to cope with this situation.
>> With additional modifiers and flags on the horizon with projects like 
>> Valhalla, addressing the existent modeling deficiency now ahead of time is 
>> reasonable before further strain is introduced.
>> This PR in its current form is meant to give the overall shape of the API. 
>> It is missing implementations to map from, say, method modifiers to access 
>> flags, taking into account overlaps in bit positions.
>> The CSR https://bugs.openjdk.java.net/browse/JDK-8281660 will be filled in 
>> once the API is further along.
> Joe Darcy has updated the pull request with a new target base due to a merge 
> or a rebase. The incremental webrev excludes the unrelated changes brought in 
> by the merge/rebase. The pull request contains 32 additional commits since 
> the last revision:
>  - Target JDK 20 rather than 19.
>  - Merge branch 'master' into JDK-8266670
>  - Add mask values to constants' javadoc.
>  - Implement review feedback from mlchung.
>  - Fix type in @throws tag.
>  - Merge branch 'master' into JDK-8266670
>  - Respond to review feedback.
>  - Merge branch 'master' into JDK-8266670
>  - Make workding changes suggested in review feedback.
>  - Merge branch 'master' into JDK-8266670
>  - ... and 22 more: 
> https://git.openjdk.java.net/jdk/compare/75552cfd...05cf2d8b

To reinforce the argument not to propagate ACC_SUPER to the new API.
It is NOT currently defined in j.l.reflect.Modifier, so there are no existing 
dependencies on a symbol.

Class.getModifiers() *never* returns ACC_SUPER; the VM explicitly removes it 
(since 2007, for all class file versions).
The note in the JVMS spec indicates it is retained only for source 
compatibility with earlier releases.
The JVMS spec considers the flag to always be set. and It is always unset in 
the modifiers returned from getModifiers().

Defining the value where it has not been defined before has no useful purpose.


PR: https://git.openjdk.java.net/jdk/pull/7445

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