[cfe-dev] Allowing checkers to mark symbols as live

[Ted Kremenek]

On Aug 9, 2010, at 12:31 PM, Jordy Rose wrote:

> 1. Look up the strlen of some string.
> 2. Conjure a symbol to represent it if we don't have one.
> 3. At the end of the statement, symbols are cleaned. Any information about
> the strlen is now lost.

I don't see how these symbols are getting lost.  This is the code from SymbolManager::isLive()

  if (const SymbolExtent *extent = dyn_cast<SymbolExtent>(sym)) {
    const MemRegion *Base = extent->getRegion()->getBaseRegion();
    if (const VarRegion *VR = dyn_cast<VarRegion>(Base))
      return isLive(VR);
    if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Base))
      return isLive(SR->getSymbol());
    return false;
  }

As long as the SymbolicRegion 'SR' is live, the symbol representing the extent should be live.  In your example, 'x' binds to a SymbolicRegion.  Since 'x' is live, so is that binding, and thus so is the symbol representing the extent.  If this not working?