RFR: 8347471: Provide valid flags and mask in AccessFlag.Location [v9]

[Roger Riggs]

On Mon, 28 Apr 2025 20:20:28 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Some AccessFlag parsing methods throw IAE because a flag mask is not valid in a location. However, there is no easy way to check what flag mask bits or what flags are valid for a location. We need such APIs to check, specific to each class file format version.
>> 
>> Also in the investigation, it's noted that `ACC_SYNTHETIC` is incorrectly represented - it is available since release 5.0 instead of release 7. This bug is fixed together for implementation simplicity.
>> 
>> The new methods are all in `AccessFlag.Location`:
>> - `Set<AccessFlag> flags()`
>> - `int flagsMask()`
>> - `Set<AccessFlag> flags(ClassFileFormatVersion)`
>> - `int flagsMask(ClassFileFormatVersion)`
>> 
>> Also there is some simplification to `AccessFlag` itself to remove the anonymous classes, which should be more startup-friendly.
>> 
>> Testing: Tier 1-3
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Wording updates, thanks Roger

The "kinds of constructs" phrase can be replaced by "Locations" and improve readability.

In AccessFlag.java: 326, there is a pre-existing "integer" that could be removed to be consistent with the other mentions of the mask.

src/java.base/share/classes/java/lang/reflect/AccessFlag.java line 342:

> 340:     /**
> 341:      * {@return kinds of constructs this flag can be applied to in the
> 342:      * current class file format version}

Suggestion:

     * {@return Locations this flag can be applied to in the
     * current class file format version}

src/java.base/share/classes/java/lang/reflect/AccessFlag.java line 352:

> 350: 
> 351:     /**
> 352:      * {@return kinds of constructs this flag can be applied to in the

Suggestion:

     * {@return Locations this flag can be applied to in the

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PR Review: https://git.openjdk.org/jdk/pull/23095#pullrequestreview-2801073592
PR Review Comment: https://git.openjdk.org/jdk/pull/23095#discussion_r2064846060
PR Review Comment: https://git.openjdk.org/jdk/pull/23095#discussion_r2064847670