Update: I've now merged the wip to our master and pushed it to the ASF gitox repo.
I think we already came pretty far and it looks really promising. So there is a high chance that we succeed, although there is still plenty of work in front of us. How it works: Basically there are 2 sets of information in the PCEnhancer right now: _managed: the BCClass version of the original class _pc: the BCClass of the generated/modified class. Might be the same as _managed but in case of subclassing or interface case it is different. In those cases _managed represents the original class and _pc the subclass/concrete implementation. managed and pc are the ASM variants of _managed and _pc. The main entry point for debugging into it is PCEnhancer#run() There are a few methods in ASMHelper to update from BCClass -> ASM and vice versa: AsmHelper.readIntoBCClass(pc, _pc); takes all the information from the ASM pc, creates a class byte[] and reads that back into the existing _pc instance. pc = AsmHelper.toClassNode(_pc); is the corresponding method in the other direction. from BCClass to ASM. Right now we have the following methods left to migrate in PCEnhancer addAttachDetachCode(); addSerializationCode(); addCloningCode(); runAuxiliaryEnhancers(); I'll be off for a week on holidays in Venice. If someone want's to join in with the effort then please go on! You might want to compare the current PCEnhancer code with an older version to get an idea how it can be done and to see some patterns I've used. As a quick hint: Java is basically a stack based virtual CPU. The 'this' pointer is on position 0 of the stack, so ALOAD 0. After that comes the parameters. The size of the param on the stack depends on the type. Mostly 1, but for long eg 2 positions. So ALOAD 1 is the 1st method parameter, ALOAD 2 the 2nd (except 1st param was a 2-pos type). In case of a static method there is ofc no 'this' on the stack, so the parameters start with zero offset. After all the parameters there are the unnamed 'local' variables. I tried to consistently name them xxxVarPos. See also the various helper methods in ASMHelper. For example for the various LOAD, RETURN, STORE operations which depends based on the type (ALOAD vs ILOAD vs IALOAD etc) Also read the guide to ASM PDF from objectweb. I'll be mostly offline till Sunday, but will try to answer mails if there are some questions. txs and LieGrue, strub > Am 19.06.2023 um 17:11 schrieb Matt Pavlovich <mattr...@gmail.com>: > > +1 thanks for tackling this, Mark! > > ASM definitely more widely used going forward. > > -Matt > >> On Jun 17, 2023, at 3:01 PM, Mark Struberg <strub...@yahoo.de.INVALID> wrote: >> >> Small update: >> >> I've worked on it over the last few weeks, and I'm getting closer >> >> >> https://github.com/struberg/openjpa/tree/fb_asmEnhance >> >> contains the latest work on the PCEnhancer. Right in the middle of replacing >> Serp with native ASM code. >> >> Note that I also had to modify a few interfaces with a few more to follow >> from BCClass to ASM ClassNode. >> >> Happy to get some feedback! >> >> If anybody wants to help with this effort I'm happy to also push this >> feature branch to our ASF repo. It looks reasonably promising already. >> >> LieGrue, >> strub >> >> >>> Am 25.05.2023 um 18:36 schrieb Mark Struberg <strub...@yahoo.de.INVALID>: >>> >>> Hi! >>> >>> Right now I'm trying to get rid of serp step by step. >>> The code is right now at my own github repo in the fb_asmEnhance branch: >>> https://github.com/struberg/openjpa/tree/fb_asmEnhance >>> >>> >>> >>> The approach I took for now is to create a few methods in AsmHelper to be >>> able to move from BCClass -> ASM ClassWriter and the other way around. That >>> way we should be able to replace functionality part by part but still keep >>> all things afloat. >>> >>> For now I've started with the PCSubclassValidator. >>> Right now this evaluates the attributs using Serp plus ASM and then compare >>> the results. >>> If something is fishy, you'll see the following >>> throw new IllegalStateException("MSX ASMTODO " + bcField + " " + field); >>> >>> >>> It would be extremely helpful, if you could go through your projects and >>> let it run and report how it's going. >>> If you see that "MSX ASMTODO" somewhere then we know I messed something up. >>> >>> I'll gonna finally remove the BCClass handling from those parts in a few >>> days. Current commit is >>> https://github.com/struberg/openjpa/commit/3ea2412003028d37f2a69971a47bb20abf589f8b >>> >>> txs and LieGrue, >>> strub >>> >>> >>> >>> >> >
