On Tue, 14 Jun 2022 02:32:54 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 incrementally with one additional > commit since the last revision: > > Respond to review feedback. src/java.base/share/classes/java/lang/reflect/AccessFlag.java line 104: > 102: */ > 103: PROTECTED(Modifier.PROTECTED, true, > 104: Set.of(Location.FIELD, Location.METHOD, > Location.INNER_CLASS)), In both space and startup time, creating separate sets for the same set of Locations is inefficient. src/java.base/share/classes/java/lang/reflect/AccessFlag.java line 213: > 211: * <code>{@value "0x%04x" Modifier#STRICT}</code>. > 212: */ > 213: STRICT(Modifier.STRICT, true, Set.of(Location.METHOD)), ACC_STRICT is defined for class files and appears in the Class.getModifiers() before class file version 46. Also it is included in Modifer.classModifiers(); Modifer.CLASS_MODIFIERS. it might be worth a note saying it is class file version specific. ------------- PR: https://git.openjdk.org/jdk/pull/7445
