Ensure termination in while/for
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432dbf32dc
commit
39f938226e
4 changed files with 24 additions and 7 deletions
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@ -179,6 +179,8 @@ and node =
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node_pos: position; (* position in the source *)
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mutable node_out: arc list; (* arcs with this node as source *)
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mutable node_in: arc list; (* arcs with this node as destination *)
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mutable widen_target : bool; (* is node a candidate for widening : either head of structured loop
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or destination of goto in goto-made loop that doesn't have any widen-target *)
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}
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and arc =
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@ -231,6 +231,7 @@ let print_cfg fmt p =
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List.iter (fun a -> Format.fprintf fmt "%i " a.arc_src.node_id) n.node_in;
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Format.fprintf fmt "out:";
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List.iter (fun a -> Format.fprintf fmt "%i " a.arc_dst.node_id) n.node_out;
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if n.widen_target then Format.fprintf fmt "(widen target)";
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Format.fprintf fmt "\n";
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) p.cfg_nodes;
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Format.fprintf fmt "\n";
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@ -36,19 +36,19 @@ let node_counter = ref 0
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let nodes = ref []
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(* create a new node, with a fresh identifier and accumulate into nodes *)
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let create_node (pos:position) =
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let create_node ?(widen_target) (pos:position) =
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incr node_counter;
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let node =
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{ node_id = !node_counter;
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node_pos = pos;
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node_in = [];
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node_out = [];
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widen_target = match widen_target with | None -> false | Some b -> b;
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}
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in
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nodes := node::(!nodes);
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node
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let arcs = ref []
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let arc_counter = ref 0
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@ -456,7 +456,7 @@ let rec stat (env:env) (entry:node) (exit:node) (s:stat) : env =
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let env1, before, e = bool_expr env expr in
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(* entry --[before]--> entry1 *)
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let entry1 = append_inst entry before in
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let node_t = create_node (fst x1) in
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let node_t = create_node ~widen_target:true (fst x1) in
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(* entry1 --[expr]--> node_t *)
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add_arc entry1 node_t (CFG_guard e);
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(* entry1 --[!expr]--> node_f *)
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@ -487,7 +487,7 @@ let rec stat (env:env) (entry:node) (exit:node) (s:stat) : env =
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| Some (expr,_) -> bool_expr env1 expr
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in
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let head1 = append_inst head before in
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let node_t = create_node (fst x1) in
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let node_t = create_node ~widen_target:true (fst x1) in
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add_arc head1 node_t (CFG_guard e);
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add_arc head1 exit (CFG_guard (CFG_bool_unary (AST_NOT, e)));
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(* increment *)
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@ -550,6 +550,16 @@ and stat_list (env:env) (entry:node) (exit:node) (l:stat ext list) : env =
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stat_list env1 next exit rest
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(*
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(* Decorate a function graph with widen targets until all loops have at least one *)
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let make_widen_target (e:node) =
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List.iter (fun x -> if(x.node_id = e.node_id) then x.widen_target <- true) !nodes
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let rec ensure_widens (entry:node) =
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type color = Unseen | Opened | Visited
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let type colnode = color * node in
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()
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*)
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(* Translate a function *)
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@ -31,7 +31,8 @@ module Iterator (D : DOMAIN) = struct
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let node_abst n = try( NodeMap.find n !func_state )with Not_found -> D.bottom in
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let update_node n s =
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func_state := NodeMap.add n (D.join s (node_abst n)) !func_state in
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let acctor = if (n.widen_target) then D.widen else D.join in
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func_state := NodeMap.add n (acctor (node_abst n) s) !func_state in
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let rec iterate n = begin
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(*Format.printf "@[<h 0> Handling node %i@]@ " n.node_id;*)
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@ -40,8 +41,11 @@ module Iterator (D : DOMAIN) = struct
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let l = List.filter (fun x -> Node.equal x.arc_src n) cfg.cfg_arcs in begin
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List.iter (fun arc -> let s = do_inst curr_abst arc in
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if D.subset s (node_abst arc.arc_dst) then ()
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else (Format.printf "@[<h 0>[%i -> %i] Got node %i state %a join %a " n.node_id arc.arc_dst.node_id arc.arc_dst.node_id
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D.print (node_abst arc.arc_dst) D.print s;
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else (let str = if arc.arc_dst.widen_target then "widen" else "join" in
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Format.printf "@[<h 0>[%i -> %i] Got node %i state %a %s %a " n.node_id arc.arc_dst.node_id arc.arc_dst.node_id
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D.print (node_abst arc.arc_dst)
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str
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D.print s;
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update_node arc.arc_dst s;
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Format.printf "= %a@]@ " D.print (node_abst arc.arc_dst);
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func_dirty := NodeSet.add arc.arc_dst !func_dirty)) l;
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