[vidarh]

You might be interested in looking at Semantic Dictionary Encoding [1]. It was professor Michael Franz' PhD thesis work. Franz' was Andreas Gals advisor on his thesis on trace trees.

SDE didn't propose starting with SSA, but could easily work with an SSA representation. SDE basically functions as a compression mechanism for an semantic IR that builds a dictionary on compression/decompression reminiscent of LZW. So instead of storing straight byte code, you store a compact higher level representation, that could very well be SSA, that is structure for you to generate code while "decompressing" it, and reuse generated code fragments as "templates" for later fragments.

An implementation was built in Oberon, compact tree representation (you could do a DAG with some adjustments) that mirrors your code generation orderand e.g. used to support PPC and M68k from the same "binares" in MacOberon. The way it was structured makes retaining arbitrary higher level structure of the programs very straight forward.

I keep wanting to do something with SDE, but life keeps intervening... I see it as a huge shame that more work didn't go into exploring that alternative to straight up bytecode, but it basically had way too little head start on Java, and I believe Franz' moved to Java for his subsequent research on code generation.

[1] https://en.wikipedia.org/wiki/Semantic_dictionary_encoding

[KMag]

Yes, I'm familiar with SDE, but thanks for mentioning it. The SafeTSA I mentioned was one of Michael Franz's later contributions to the field. SafeTSA was an SSA representation capable of expressing all of the security and other semantic constraints of the Java language. Michael Franz's group took the Jikes RVM (then known as Japapeno) and added a second front-end to the JIT that could read SafeTSA, so they could test performance of programs running Java bytecode and SafeTSA in the same process. SafeTSA both took less time to go from bytecode to native code, but also the resulting native code ran faster.

[amelius]

Interesting. Do you have a link to the thesis? The link on wikipedia seems broken, and Franz's homepage doesn't seem to contain a link.

[cybernet]

The name of the paper is "Code-Generation On-the-Fly: A Key to Portable Software" just search for it.