Currently the version of ASM bundled in Clojure is pretty old (circa 2005). There are some documented performance improvements in newer versions of ASM that should speed up some things in Clojure. We would like to move to the latest stable version of ASM (4.1); the current Clojure code uses 3.3.1.
It may not be the desired approach, but CLJ-713 has a patch related to this.
Open Questions to Resolve
Some open questions:
- Should we use ASM jar as is (make the dependency public) or use re-rooted versions that cannot conflict?
- Scala: 2.10+ uses ASM 4.1, subsetted, and rerooted to scala.tools.asm
- Groovy: 2.1 (latest stable) uses ASM 4.0 external, 2.2 (next) uses ASM 4.1 external
- JRuby: 1.7.4 (latest stable) uses ASM 4.1 (I think), subsetted, and rerooted to org.jruby.org.objectweb.asm
- Recommend: re-root to avoid conflicts
- What (if anything) needs to be done with computing stack frames to satisfy bytecode verification changes in JDK 7?
- If using a re-rooted version should that version be provided in a separate jar for separability in environments which do not need it?
- If re-rooted, should we subset the jar and only include what we use rather than the whole jar?