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Diffstat (limited to 'cil/src/ext/oneret.ml')
| -rw-r--r-- | cil/src/ext/oneret.ml | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/cil/src/ext/oneret.ml b/cil/src/ext/oneret.ml new file mode 100644 index 00000000..b3ce4a10 --- /dev/null +++ b/cil/src/ext/oneret.ml @@ -0,0 +1,187 @@ +(* MODIF: Loop constructor replaced by 3 constructors: While, DoWhile, For. *) + +(* + * + * Copyright (c) 2001-2002, + * George C. Necula <necula@cs.berkeley.edu> + * Scott McPeak <smcpeak@cs.berkeley.edu> + * Wes Weimer <weimer@cs.berkeley.edu> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 3. The names of the contributors may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER + * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + *) + +(* Make sure that there is exactly one Return statement in the whole body. + * Replace all the other returns with Goto. This is convenient if you later + * want to insert some finalizer code, since you have a precise place where + * to put it *) +open Cil +open Pretty + +module E = Errormsg + +let dummyVisitor = new nopCilVisitor + +let oneret (f: Cil.fundec) : unit = + let fname = f.svar.vname in + (* Get the return type *) + let retTyp = + match f.svar.vtype with + TFun(rt, _, _, _) -> rt + | _ -> E.s (E.bug "Function %s does not have a function type\n" + f.svar.vname) + in + (* Does it return anything ? *) + let hasRet = match unrollType retTyp with TVoid _ -> false | _ -> true in + + (* Memoize the return result variable. Use only if hasRet *) + let lastloc = ref locUnknown in + let retVar : varinfo option ref = ref None in + let getRetVar (x: unit) : varinfo = + match !retVar with + Some rv -> rv + | None -> begin + let rv = makeLocalVar f "__retres" retTyp in (* don't collide *) + retVar := Some rv; + rv + end + in + (* Remember if we have introduced goto's *) + let haveGoto = ref false in + (* Memoize the return statement *) + let retStmt : stmt ref = ref dummyStmt in + let getRetStmt (x: unit) : stmt = + if !retStmt == dummyStmt then begin + (* Must create a statement *) + let rv = + if hasRet then Some (Lval(Var (getRetVar ()), NoOffset)) else None + in + let sr = mkStmt (Return (rv, !lastloc)) in + retStmt := sr; + sr + end else + !retStmt + in + (* Now scan all the statements. Know if you are the main body of the + * function and be prepared to add new statements at the end *) + let rec scanStmts (mainbody: bool) = function + | [] when mainbody -> (* We are at the end of the function. Now it is + * time to add the return statement *) + let rs = getRetStmt () in + if !haveGoto then + rs.labels <- (Label("return_label", !lastloc, false)) :: rs.labels; + [rs] + + | [] -> [] + + | ({skind=Return (retval, l)} as s) :: rests -> + currentLoc := l; +(* + ignore (E.log "Fixing return(%a) at %a\n" + insert + (match retval with None -> text "None" + | Some e -> d_exp () e) + d_loc l); +*) + if hasRet && retval = None then + E.s (error "Found return without value in function %s\n" fname); + if not hasRet && retval <> None then + E.s (error "Found return in subroutine %s\n" fname); + (* Keep this statement because it might have labels. But change it to + * an instruction that sets the return value (if any). *) + s.skind <- begin + match retval with + Some rval -> Instr [Set((Var (getRetVar ()), NoOffset), rval, l)] + | None -> Instr [] + end; + (* See if this is the last statement in function *) + if mainbody && rests == [] then + s :: scanStmts mainbody rests + else begin + (* Add a Goto *) + let sgref = ref (getRetStmt ()) in + let sg = mkStmt (Goto (sgref, l)) in + haveGoto := true; + s :: sg :: (scanStmts mainbody rests) + end + + | ({skind=If(eb,t,e,l)} as s) :: rests -> + currentLoc := l; + s.skind <- If(eb, scanBlock false t, scanBlock false e, l); + s :: scanStmts mainbody rests +(* + | ({skind=Loop(b,l,lb1,lb2)} as s) :: rests -> + currentLoc := l; + s.skind <- Loop(scanBlock false b, l,lb1,lb2); + s :: scanStmts mainbody rests +*) + | ({skind=While(e,b,l)} as s) :: rests -> + currentLoc := l; + s.skind <- While(e, scanBlock false b, l); + s :: scanStmts mainbody rests + | ({skind=DoWhile(e,b,l)} as s) :: rests -> + currentLoc := l; + s.skind <- DoWhile(e, scanBlock false b, l); + s :: scanStmts mainbody rests + | ({skind=For(bInit,e,bIter,b,l)} as s) :: rests -> + currentLoc := l; + s.skind <- For(scanBlock false bInit, e, scanBlock false bIter, + scanBlock false b, l); + s :: scanStmts mainbody rests + | ({skind=Switch(e, b, cases, l)} as s) :: rests -> + currentLoc := l; + s.skind <- Switch(e, scanBlock false b, cases, l); + s :: scanStmts mainbody rests + | ({skind=Block b} as s) :: rests -> + s.skind <- Block (scanBlock false b); + s :: scanStmts mainbody rests + | ({skind=(Goto _ | Instr _ | Continue _ | Break _ + | TryExcept _ | TryFinally _)} as s) + :: rests -> s :: scanStmts mainbody rests + + and scanBlock (mainbody: bool) (b: block) = + { bstmts = scanStmts mainbody b.bstmts; battrs = b.battrs; } + + in + ignore (visitCilBlock dummyVisitor f.sbody) ; (* sets CurrentLoc *) + lastloc := !currentLoc ; (* last location in the function *) + f.sbody <- scanBlock true f.sbody + + +let feature : featureDescr = + { fd_name = "oneRet"; + fd_enabled = Cilutil.doOneRet; + fd_description = "make each function have at most one 'return'" ; + fd_extraopt = []; + fd_doit = (function (f: file) -> + Cil.iterGlobals f (fun glob -> match glob with + Cil.GFun(fd,_) -> oneret fd; + | _ -> ())); + fd_post_check = true; + } |