The Shape of Code

I have been rather remiss in revisiting the predictions I made for 2009 to see how they fared. Only two out of the six predictions were sufficiently precise to enable an assessment one year later; the other four talking more about trends. What of these two predictions?

The LLVM project will die. Ok, the project is still going and at the end of December the compiler could build itself but the build is not yet in a state to self host (i.e., llvm compiler creates an executable of itself from its own source and this executable can build an executable from source that is identical to itself {modulo date/time stamps etc}). Self hosting is a major event and on some of the projects I have worked on it has been a contractual payment milestone.

Is llvm competition for gcc? While there might not be much commercial competition as such (would Apple be providing funding to gcc if it were not involved in llvm?), I’m sure that developers working on both projects want their respective compiler to be the better one. According to some llvm benchmarks they compile code twice as fast as gcc. If this performance difference holds up across lots of source how might the gcc folk respond? Is gcc compiler time performance an issue that developers care about or is quality of generated code more important? For me the latter is more important and I have not been able to find a reliable, recent, performance comparison. I understand that almost all gcc funding is targeted at code generation related development, so if compile time is an issue gcc may be in a hole.

I still don’t see the logic behind Apple funding this project and continue to think that this funding will be withdrawn sometime, perhaps I was just a year off. I do wish the llvm developers well and look forward to them celebrating a self hosted compiler.

Static analysis will go mainstream. Ok, I was overly optimistic here. There do not seem to have been any casualties in 2009 among the commercial vendors selling static analysis tools and the growth of PHP has resulted in a number of companies selling tools that scan for source security vulnerabilities (.e.g, SQL injection attacks).

I was hoping that the availability of Treehydra would spark the development of static analysis plugins for gcc. Perhaps the neatness of the idea blinded me to what I already knew; many developers dislike the warnings generated by the -Wall option and therefore might be expected to dislike any related kind of warning. One important usability issue is that Treehydra operates on the abstract syntax tree representation used internally by gcc, GIMPLE. Learning about this representation requires a big investment before a plugin developer becomes productive.

One tool that did experience a lot of growth in 2009 was Coccinelle, at least judged by the traffic on its mailing list. The Coccinelle developers continue to improve it and are responsive the questions. Don’t be put off by the low version number (currently 0.2), it is much better than most tools with larger version numbers.