[gnu.gcc] use/def sets of program statements

hira@sneaky.bellcore.com (Hira Agrawal) (06/28/89)

I need to compute def and use sets of all statements in a C program. 

Def set of a statement is set of all variables (actually l-valued 
expressions) whose values could be modified by that statement. Use
set of a statement is the set of all l-valued expressions whose values 
are used in computing the def-set values of that statement. Def/use
sets of compound statements (if, while, etc.) are computed by taking
the union of def/use sets of all their constituent statements.

What are the possible ways of computing these sets while compiling a
program with gcc? One way could be to do so while parsing the program.
Is there any way I could do the same from RTL code? I am not too
familiar with internals of gcc, so I wish to investigate various
options before starting to code any one. 

I'll appreciate any help in this regard. Thanks.

-- Hira.
   hira@wind.bellcore.com