What does Coverity/clang static analysis actually do?

[Walter Bright]

Rainer Schuetze wrote:
> I've run the analysis on the dmd source code, but deactivated some
> warnings regarding memory leaks and variable hiding to not get flooded
> with messages. After that, code analysis added about 150 warnings to the
> 1000 already issued by the compiler (mostly "signed/unsigned mismatch"
> and "unreferenced local variable").

Could you turn it all on, run it through the dmd source code, and send 
me the results? I'd like to see if it detected any real bugs.