Svadev mailing list

[Matthew Wala <wala1 AT illinois.edu>]

On Apr 5, 2011, at 11:43 PM, John Criswell wrote:

> On 4/5/2011 7:56 PM, Matthew Wala wrote:
> > Hi everyone:
> >
> > What's the purpose of the "complete" byte which is passed as an
> > argument and the end of the pool_* string
> > functions?
>
> The Complete flag is a DSA flag set on a DSNode.  It indicates that 
> the DSA information computed for the DSNode is as complete as it can 
> be: everything that can be known about the memory object has been 
> computed.

Why would the string function transform module need this information? 
Does its presence affect the guarantee of
memory safety, or is it there for some other work, or can we take it 
out?

> This is a problem unrelated to completeness.  In this case, DSA does 
> not create a DSNode for the null pointer constant.  In this instance, 
> you should create a NULL Pool handle and pass that in.  If the string 
> function is supposed to handle NULL string pointers, then your 
> run-time checks should be adjusted to take NULL pool handles and NULL 
> pointers into account.
>
> For a NULL constant pointer, you can consider it Complete since it is 
> trivial to know everything about it that we care to know.

Okay - it seems I can fix the error I'm getting by checking the pointer 
for a NULL constant and
marking it complete if it is one.
What do you mean by creating a NULL Pool handle? If I am not mistaken a 
NULL pool handle is already created
by the StringTransform module, then filled by poolalloc, for every 
string parameter. Doesn't poolalloc
already fill the pool handle for the NULL constant?

Thanks for your reply,

Matt