Is there any way to take advantage of Microsoft's SAL, e.g. through a C parser that preserves this information? Or is it made by Microsoft, for Microsoft's internal use only?
It would be immensely useful for a lot of tasks, such as creating C library bindings for other languages.
Not sure what you mean by "take advantage of", but currently the VS 2011 Beta uses the SAL annotations when performing code analysis, via the the /analyze option. the annotations are just pure macro's from sal.h which Microsoft encourages the use of (at least in a VS environment).
If you just want to preserve the info after a preprocessing step, you could just make the macro's expand to themselves or just alter one of the exisitng open-source pre-processors to exclude the symbols (VS also has a few expansion options from the SAL macro's), but using the information provided by the annotations will require something along the lines of a custom LLVM pre-pass or GCC plugin to do this (if compiling the code, though you can at the same time use them for binding generation).
SAL annotations can find tons of bugs with static analysis.
http://msdn.microsoft.com/en-us/library/windows/hardware/hh454825(v=vs.85).aspx
I have never had to set it from scratch, but my development environment will use prefast to do static analysis everytime I build something. Finding bugs at compile time is better than finding them at runtime.
Source annotations as far as my own personal experience has seen, is a useful way to quickly see how parameters are supposed to be passed or how they are assumed to be passed. As far as taking advantage of that, I agree that a prepass might be the only way to take real advantage, and might i suggest writing your own if you have specific needs or expectations on it's output. Hope I helped..
