Advogato blog for pnkfelix

22 Jun 2002

Sat, 22 Jun 2002 08:44:32 GMT

Well, much has changed in my life since the last time I posted to this list. I finished my thesis (register allocation), finished school, and went off to work as a compiler engineer at Green Hills Software.

And yet not that much has changed at the same time... (hint: I have not managed to escape the spectre of register allocation, though at least its on a different compiler this time)

I am trying to pursue some projects in my free time, though I have to admit that I am not doing as much as before to further the cause of free software...

Unrelated topic: you'd be better off investing your time in reading "The Art of Computer Programming" than in reading Wolfram's new book, "A New Kind of Science", but if you've already read the former a couple times, maybe you'll have the attention span to wade through the latter. C:P

15 Oct 2000

Sun, 15 Oct 2000 14:44:36 GMT

Well, at long long last I can finally get globally register allocated output that runs. Very exciting.

Needs speeding up though. Seems like I just got through hacking the local allocator into producing output in an acceptable amount of time. Also may not be entirely bug-free. sigh

6.170 has been a distraction, but it hasn't been too too bad. I've been careful not to get as sucked in this term as I did last term. Spending more time writing high-level documents to be disseminated amongst all of the students, as opposed to helping individuals like last term (though I have seen a fair share of that this term as well). Takes a long time to write up something like that and get it right, but seems to be worth it in the end; really gives me a firm grip on understanding things.

Went to mall yesterday, bought an alarm clock, and a watch. Spent some time in Borders reading a book on "Generative Programming." Thought that it was going to be cool, but ended up being disappointing; either told me things I already knew or dealt with analysis and terminology. Maybe will be better after I read "Analysis Patterns"... don't think so though.

Also seemed in many ways just geared to promote the notation that the author pushes in the book itself; I've seen plenty of that, sure. But no reason to spend the time right now emersing myself in a totally different modelling notation, especially one that doesn't seem to be a significant win over Alloy. Have to wait and see.

27 Jul 2000

Thu, 27 Jul 2000 04:49:30 GMT

Finally got the Graph Coloring subsystem to work in a compatible fashion with the Intermediate Representation... I've only tested it on an abstract assembly language, but I think the hard part is over. I've said that a lot the past few days...

At least I'm happy with the new interface I've defined for the Graph classes... its remarkable to see the differences from the old versions (which I developed a year and a half ago and seriously screwed up in terms of extensibility...) Got to some how distill that design knowledge sometime over this weekend... write it down so that I can transfer it to students this term...

The thing that sucks is that I haven't been checking the builds often enough during my work over the last three days, and somewhere in there the Compiler got broken. I strongly suspect that its my Local Register Allocator that's causing the problem (as usual), except that I thought that I tested the executables after i made my last big change to that... (update: Nope, I reverted back to a good LocalRegAlloc (I think) and it still breaks... is it possible the GraphColoring is failing? Going to revert that slightly...)

In any case, the last two hours have taught me a lot about what NOT to do when trying to work with cvs... I really would have preferred a graphical interface... didn't cyclic market a GUI layer before it went under?

The compiler's also going DOG SLOW at this point... maybe the jit got turned off... C:P (Update: even better; my $PATH was pointing at the 1.2 JDK instead of the 1.3. Amazing what a difference there is between the two...)

14 Jul 2000

Fri, 14 Jul 2000 07:32:27 GMT

Wow, it took me forever to remember what my password was...

In Java profiling hell right now... my compiler pass (that theoretically takes linear time) was identified as being 5 times slower than a similar (actually much more ambitious, though not necessarily linear) pass that my officemate hacked up.

I've managed to get the time down by a factor of 2 or so since then by playing with the order of basicblock traversals in the data-flow analyses but am not sure where the remaining hotspots are...

Continually frustrated by several aspects of Java language and libraries, but mostly by the lack of parameterized types. A student in the my group for 6.035 (Compiler Engineering) once told me that he had never seen any useful feature of parameterized types; am now convinced that anyone who would say such a thing has never coded a compiler (or perhaps any largish system?) before (I certainly know that he wasn't doing the coding for our system).

Can't wait for GJ to get integrated into Java3 or whatever.