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Diffstat (limited to 'cil/src/ext/usedef.ml')
| -rwxr-xr-x | cil/src/ext/usedef.ml | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/cil/src/ext/usedef.ml b/cil/src/ext/usedef.ml new file mode 100755 index 0000000..57f226a --- /dev/null +++ b/cil/src/ext/usedef.ml @@ -0,0 +1,188 @@ +(* MODIF: Loop constructor replaced by 3 constructors: While, DoWhile, For. *) + + +open Cil +open Pretty + +(** compute use/def information *) + +module VS = Set.Make (struct + type t = Cil.varinfo + let compare v1 v2 = Pervasives.compare v1.vid v2.vid + end) + +(** Set this global to how you want to handle function calls *) +let getUseDefFunctionRef: (exp -> VS.t * VS.t) ref = + ref (fun _ -> (VS.empty, VS.empty)) + +(** Say if you want to consider a variable use *) +let considerVariableUse: (varinfo -> bool) ref = + ref (fun _ -> true) + + +(** Say if you want to consider a variable def *) +let considerVariableDef: (varinfo -> bool) ref = + ref (fun _ -> true) + +(** Save if you want to consider a variable addrof as a use *) +let considerVariableAddrOfAsUse: (varinfo -> bool) ref = + ref (fun _ -> true) + +(* When this is true, only definitions of a variable without + an offset are counted as definitions. So: + a = 5; would be a definition, but + a[1] = 5; would not *) +let onlyNoOffsetsAreDefs: bool ref = ref false + +let varUsed: VS.t ref = ref VS.empty +let varDefs: VS.t ref = ref VS.empty + +class useDefVisitorClass : cilVisitor = object (self) + inherit nopCilVisitor + + (** this will be invoked on variable definitions only because we intercept + * all uses of variables in expressions ! *) + method vvrbl (v: varinfo) = + if (!considerVariableDef) v && + not(!onlyNoOffsetsAreDefs) then + varDefs := VS.add v !varDefs; + SkipChildren + + (** If onlyNoOffsetsAreDefs is true, then we need to see the + * varinfo in an lval along with the offset. Otherwise just + * DoChildren *) + method vlval (l: lval) = + if !onlyNoOffsetsAreDefs then + match l with + (Var vi, NoOffset) -> + if (!considerVariableDef) vi then + varDefs := VS.add vi !varDefs; + SkipChildren + | _ -> DoChildren + else DoChildren + + method vexpr = function + Lval (Var v, off) -> + ignore (visitCilOffset (self :> cilVisitor) off); + if (!considerVariableUse) v then + varUsed := VS.add v !varUsed; + SkipChildren (* So that we do not see the v *) + + | AddrOf (Var v, off) + | StartOf (Var v, off) -> + ignore (visitCilOffset (self :> cilVisitor) off); + if (!considerVariableAddrOfAsUse) v then + varUsed := VS.add v !varUsed; + SkipChildren + + | _ -> DoChildren + + (* For function calls, do the transitive variable read/defs *) + method vinst = function + Call (_, f, _, _) -> begin + (* we will call DoChildren to compute the use and def that appear in + * this instruction. We also add in the stuff computed by + * getUseDefFunctionRef *) + let use, def = !getUseDefFunctionRef f in + varUsed := VS.union !varUsed use; + varDefs := VS.union !varDefs def; + DoChildren; + end + | Asm(_,_,slvl,_,_,_) -> List.iter (fun (s,lv) -> + match lv with (Var v, off) -> + if s.[0] = '+' then + varUsed := VS.add v !varUsed; + | _ -> ()) slvl; + DoChildren + | _ -> DoChildren + +end + +let useDefVisitor = new useDefVisitorClass + +(** Compute the use information for an expression (accumulate to an existing + * set) *) +let computeUseExp ?(acc=VS.empty) (e: exp) : VS.t = + varUsed := acc; + ignore (visitCilExpr useDefVisitor e); + !varUsed + + +(** Compute the use/def information for an instruction *) +let computeUseDefInstr ?(acc_used=VS.empty) + ?(acc_defs=VS.empty) + (i: instr) : VS.t * VS.t = + varUsed := acc_used; + varDefs := acc_defs; + ignore (visitCilInstr useDefVisitor i); + !varUsed, !varDefs + + +(** Compute the use/def information for a statement kind. Do not descend into + * the nested blocks. *) +let computeUseDefStmtKind ?(acc_used=VS.empty) + ?(acc_defs=VS.empty) + (sk: stmtkind) : VS.t * VS.t = + varUsed := acc_used; + varDefs := acc_defs; + let ve e = ignore (visitCilExpr useDefVisitor e) in + let _ = + match sk with + Return (None, _) -> () + | Return (Some e, _) -> ve e + | If (e, _, _, _) -> ve e + | Break _ | Goto _ | Continue _ -> () +(* + | Loop (_, _, _, _) -> () +*) + | While _ | DoWhile _ | For _ -> () + | Switch (e, _, _, _) -> ve e + | Instr il -> + List.iter (fun i -> ignore (visitCilInstr useDefVisitor i)) il + | TryExcept _ | TryFinally _ -> () + | Block _ -> () + in + !varUsed, !varDefs + +(* Compute the use/def information for a statement kind. + DO descend into nested blocks *) +let rec computeDeepUseDefStmtKind ?(acc_used=VS.empty) + ?(acc_defs=VS.empty) + (sk: stmtkind) : VS.t * VS.t = + let handle_block b = + List.fold_left (fun (u,d) s -> + let u',d' = computeDeepUseDefStmtKind s.skind in + (VS.union u u', VS.union d d')) (VS.empty, VS.empty) + b.bstmts + in + varUsed := acc_used; + varDefs := acc_defs; + let ve e = ignore (visitCilExpr useDefVisitor e) in + match sk with + Return (None, _) -> !varUsed, !varDefs + | Return (Some e, _) -> + let _ = ve e in + !varUsed, !varDefs + | If (e, tb, fb, _) -> + let _ = ve e in + let u, d = !varUsed, !varDefs in + let u', d' = handle_block tb in + let u'', d'' = handle_block fb in + (VS.union (VS.union u u') u'', VS.union (VS.union d d') d'') + | Break _ | Goto _ | Continue _ -> !varUsed, !varDefs +(* + | Loop (b, _, _, _) -> handle_block b +*) + | While (_, b, _) -> handle_block b + | DoWhile (_, b, _) -> handle_block b + | For (_, _, _, b, _) -> handle_block b + | Switch (e, b, _, _) -> + let _ = ve e in + let u, d = !varUsed, !varDefs in + let u', d' = handle_block b in + (VS.union u u', VS.union d d') + | Instr il -> + List.iter (fun i -> ignore (visitCilInstr useDefVisitor i)) il; + !varUsed, !varDefs + | TryExcept _ | TryFinally _ -> !varUsed, !varDefs + | Block b -> handle_block b |