On Wed, 8 Mar 2023 15:50:05 GMT, Coleen Phillimore <cole...@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. > > src/hotspot/share/classfile/classFileParser.cpp line 1608: > >> 1606: fflags.update_injected(true); >> 1607: AccessFlags aflags; >> 1608: FieldInfo fi(aflags, (u2)(injected[n].name_index), >> (u2)(injected[n].signature_index), 0, fflags); > > I don't know why there's a cast here until I read more. If the FieldInfo > name_index and signature_index fields are only u2 sized, could you pass this > as an int and then in the constructor assert that the value doesn't overflow > u2 instead? The type of name_index and signature_index is const vmSymbolID, because they names and signatures of injected fields do not come from a constant pool, but from the vmSymbol array. ------------- PR: https://git.openjdk.org/jdk/pull/12855
