Re: Jimple Canonical Form

[Patrick LAM <plam@sable.mcgill.ca>]

On Fri, 5 Sep 2003, Venkatesh Prasad Ranganath wrote:

> Sorry, I used the wrong term.  I meant "deterministic".  However, the
> question is to what extent is the creation of Jimple deterministic?  As
> you said, all else being equal or same across the 2 runs, can the user
> assume the following?

>   1> Identical identifiers represent the same variable, i.e., $r0 in the
> both bodies of a method identify the same variable.

>   2> Given a Stmt object AssignStmt(Local($r1) = Local($r2) +
> Local($r3)), one can obtain the use/def boxes as a List via
> getUseDefBoxes() call and the order of the boxes in the list will be
> same for the same statement in different bodies of the same method.

>   3> The order of the statements in different bodies of a method are
> identical.

Yes.  This is the desired behaviour of Soot.  If this is not the actual
behaviour of Soot, then it is a bug; please tell us about it, or supply a
patch.

We needed determinism to make our regression tests work; otherwise it was
quite difficult to compare Jimple output across runs.  I think Raja's
thesis has a small section on how he created DeterministicHashMap to fix
the main part of the problem here.

pat