[cfe-dev] Attempting to modify SimpleStreamChecker for a different file API

[Peeter Joot]

I'm interested in trying out clang based code analysis.  I saw the
following slides:

http://llvm.org/devmtg/2012-11/Zaks-Rose-Checker24Hours.pdf

So thought I'd try
using tools/clang/lib/StaticAnalyzer/Checkers/SimpleStreamChecker.cpp as a
base for a similar check using our products' internal file API.

In the sample, there's the following code to get the close parameter:

void SimpleStreamChecker::checkPreCall
...
  // Get the symbolic value corresponding to the file handle.
  SymbolRef FileDesc = Call.getArgSVal(0).getAsSymbol();

I'll want to do the same thing, with a small difference.  My close API
looks like:

struct my_filehandle { int fh ; ... } ;

int myclose( my_filehandle & fh )

so once I get the close parameter symbol, I have the task of looking up the
actual file descriptor.

I'm guessing that I have to:

1) check it for -1 instead of NULL (hardcoding the assumption for now that
I'm only running this checking on Unix)

I've changed:

ConditionTruthVal OpenFailed = CMgr.isNull(State, Sym);

to call isNegative(), which I think will do the trick, provided I first:

2) find the symbol that the myclose() parameter is a reference to.
3) look up the my_filehandle::fh value out of that symbol.
4) put that ::fh symbol in the checker stream instead of the FILE*.

Anybody willing to give any tips on how to do 2-3 above.

-- 
Peeter
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