On Fri, 3 Mar 2023 14:50:34 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. This pull request has now been integrated. Changeset: bfb812a8 Author: Frederic Parain <fpar...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/bfb812a8ff8bca70aed7695c73f019ae66ac6f33 Stats: 1790 lines in 54 files changed: 927 ins; 483 del; 380 mod 8292818: replace 96-bit representation for field metadata with variable-sized streams Co-authored-by: John R Rose <jr...@openjdk.org> Co-authored-by: Chris Plummer <cjplum...@openjdk.org> Reviewed-by: dholmes, coleenp, cjplummer, dnsimon ------------- PR: https://git.openjdk.org/jdk/pull/12855
