A CIL Tutorial - Department of Computer Science - ETH Zürich

CHAPTER 3. DATAFLOW ANALYSIS 31
DoChildren
method vinst i =
try let data = L.hd state list in
current state ← Some(data);
state list ← L.tl state list;
DoChildren
with Failure "hd" → DoChildren
method get cur vml () =
match current state with
| None → getOddEvens sid
| Some vml → Some vml
end
The class varUseReporterClass inherits from vmlVisitorClass. Whenever it visits a variable use,
it emits the oekind it nds for it in the current state as given by super#get cur vml().
class varUseReporterClass = object(self)
inherit vmlVisitorClass as super
method vvrbl (vi : varinfo) =
match self#get cur vml () with
| None → SkipChildren
| Some vml → begin
if L.mem assoc vi.vid vml then begin
let vm = (vi.vid, L.assoc vi.vid vml) in
E.log "%a: %a\n" d loc (!currentLoc) varmap list pretty [vm]
end;
SkipChildren
end
end
The function evenOddAnalysis computes the OddEven analysis. It then invokes the varUseReporter
visitor. Note that we have to coerce our visitor to a nopCilVisitor because we added the
get cur vml() method.
let evenOddAnalysis (fd : fundec) (loc : location) : unit =
computeOddEven fd;
let vis = ((new varUseReporterClass) :> nopCilVisitor) in
ignore(visitCilFunction vis fd)
The tut3 function is the entry point to this module. It applies evenOddAnalysis to all functions.
let tut3 (f : file) : unit =
iterGlobals f (onlyFunctions evenOddAnalysis)