[cfe-dev] evaluating a LAnd expr in the static checker

[McDowell, Raymond C. via cfe-dev]

I am trying to construct a constraint that says 0 <= Offset <= Size, for two SVals Offset and Size.  Here's what I did:

  ASTContext &ACtx = ChCtx.getASTContext();
  SValBuilder &SVBldr = St->getStateManager().getSValBuilder();
  SVal Zero = SVBldr.makeZeroVal(ACtx.getSizeType());
  SVal OffsetIsNonNeg = SVBldr.evalBinOpNN(St, BO_LE, Zero.castAs<NonLoc>(), Offset.castAs<NonLoc>(), ACtx.BoolTy);
  SVal OffsetIsWithinSize = SVBldr.evalBinOpNN(St, BO_LE, Offset.castAs<NonLoc>(), BuffSize.castAs<NonLoc>(), ACtx.BoolTy);
  SVal OffsetIsWithinBounds = SVBldr.evalBinOpNN(St, BO_LAnd, OffsetIsNonNeg.castAs<NonLoc>(), OffsetIsWithinSize.castAs<NonLoc>(), ACtx.BoolTy);


When I run this code, it fails with an error: Assertion `false && "Invalid Opcode."' failed.  This is coming from evalAPSInt in BasicValueFactory.cpp.  This function contains a comment that says "Land, LOr, Comma are handled specially by higher-level logic."  Land does not seem to be handled by higher-level logic in this case.  I intend to work around this by asserting these as two separate constraints instead of combining them into one.  But this looks like a bug to me, so thought I should raise the issue here.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20160603/c23bdd8d/attachment.html>