Re: Finding max stack height and number of locals

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

I've added Clark Verbrugge, the author of Coffi, to the CC list of this
email.

On Thu, 18 Oct 2001, Ole Friis Ostergaard wrote:

> Does anybody know how to find the maximum stack height and the number of
> local variables for a method, as specified in the .class file?

Soot does not preserve information about the initial classfile; it is,
after all, quite difficult to analyze.  If you really want to deal with
the classfile, you can use Coffi directly.  Clark Verbrugge's web page is
at

http://www.sable.mcgill.ca/~clump/

and if you follow the research link, you'll be able to download an
un-Sootified version of Coffi.

Soot does have the Baf intermediate representation, which is
bytecode-like, but doesn't have evil representation issues.  I believe
that the maximum stack height gets computed from the Baf code.

> I need this information, and it seems that coffi retrieves this
> information during the loading of a class in ClassFile.java (line 639
> and 640 - ca.max_stack and ca.max_locals), but I (and a couple of other
> guys) cannot see if this information is thrown away by Soot, or if it is
> actually possible to retrieve it somehow.

This is not a supported Soot interface.  We do not recommend that you try
to access the Coffi libraries used by Soot as a backend.

pat