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delete old preanalysis code

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Reviewed By: jvillard

Differential Revision: D3293103

fbshipit-source-id: 83b5ea8
master
Sam Blackshear 9 years ago committed by Facebook Github Bot 5
parent 3b6fa0939b
commit 6e75c1e33f
1 changed files with 1 additions and 338 deletions
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337
infer/src/backend/preanal.ml
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@ -10,332 +10,6 @@
open! Utils
module L = Logging
(** find all the predecessors of nodes, using exception links *)
module AllPreds = struct
module NodeHash = Cfg.NodeHash
let preds_table = NodeHash.create 3 (* table from node to set of predecessors *)
let clear_table () =
NodeHash.clear preds_table
let mk_table cfg =
let do_pdesc _ pdesc =
let exit_node = Cfg.Procdesc.get_exit_node pdesc in
let add_edge is_exn nfrom nto =
if is_exn && Cfg.Node.equal nto exit_node then ()
else
try
let preds = NodeHash.find preds_table nto in
let preds' = Cfg.NodeSet.add nfrom preds in
NodeHash.replace preds_table nto preds'
with Not_found ->
NodeHash.add preds_table nto (Cfg.NodeSet.singleton nfrom) in
let do_node n =
IList.iter (add_edge false n) (Cfg.Node.get_succs n);
IList.iter (add_edge true n) (Cfg.Node.get_exn n) in
let proc_nodes = Cfg.Procdesc.get_nodes pdesc in
IList.iter do_node proc_nodes in
clear_table ();
Cfg.iter_proc_desc cfg do_pdesc
let get_preds n =
try
let preds = NodeHash.find preds_table n in
Cfg.NodeSet.elements preds
with Not_found ->
Cfg.Node.get_preds n
end
module Vset = AddressTaken.PvarSet
let is_not_function cfg x =
let pname = Procname.from_string_c_fun (Mangled.to_string (Pvar.get_name x)) in
Cfg.Procdesc.find_from_name cfg pname = None
(** variables read in the expression *)
let rec use_exp cfg pdesc (exp: Sil.exp) acc =
match exp with
| Sil.Var _ | Sil.Sizeof _ -> acc
| Sil.Const (Cclosure { captured_vars; }) ->
IList.fold_left
(fun vset_acc (_, captured_pvar, _) -> Vset.add captured_pvar vset_acc)
acc
captured_vars
| Sil.Const
(Cint _ | Cfun _ | Cstr _ | Cfloat _ | Cattribute _ | Cexn _ | Cclass _ | Cptr_to_fld _) ->
acc
| Sil.Lvar x -> Vset.add x acc
| Sil.Cast (_, e) | Sil.UnOp (_, e, _) | Sil.Lfield (e, _, _) -> use_exp cfg pdesc e acc
| Sil.BinOp (_, e1, e2) | Sil.Lindex (e1, e2) -> use_exp cfg pdesc e1 (use_exp cfg pdesc e2 acc)
and use_etl cfg pdesc (etl: (Sil.exp * Sil.typ) list) acc =
IList.fold_left (fun acc (e, _) -> use_exp cfg pdesc e acc) acc etl
and use_instr cfg (pdesc: Cfg.Procdesc.t) (instr: Sil.instr) acc =
match instr with
| Sil.Set (_, _, e, _)
| Sil.Letderef (_, e, _, _) -> use_exp cfg pdesc e acc
| Sil.Prune (e, _, _, _) -> use_exp cfg pdesc e acc
| Sil.Call (_, _, etl, _, _) -> use_etl cfg pdesc etl acc
| Sil.Nullify _ -> acc
| Sil.Abstract _ | Sil.Remove_temps _ | Sil.Stackop _ | Sil.Declare_locals _ -> acc
(** variables written in the expression *)
let rec def_exp cfg (exp: Sil.exp) acc =
match exp with
| Sil.Lvar x -> if is_not_function cfg x then Vset.add x acc else acc
| Sil.Cast (_, e) -> def_exp cfg e acc
| _ -> acc
let rec def_instr cfg (instr: Sil.instr) acc =
match instr with
| Sil.Set (e, _, _, _) -> def_exp cfg e acc
| Sil.Call _ | Sil.Letderef _ | Sil.Prune _ -> acc
| Sil.Nullify (x, _) ->
if is_not_function cfg x then Vset.add x acc else acc
| Sil.Abstract _ | Sil.Remove_temps _ | Sil.Stackop _ | Sil.Declare_locals _ -> acc
and def_instrl cfg instrs acc =
IList.fold_left (fun acc' i -> def_instr cfg i acc') acc instrs
(** variables written by instructions in the node *)
let def_node cfg node acc =
match Cfg.Node.get_kind node with
| Cfg.Node.Start_node _ | Cfg.Node.Exit_node _ | Cfg.Node.Join_node | Cfg.Node.Skip_node _ -> acc
| Cfg.Node.Prune_node _
| Cfg.Node.Stmt_node _ ->
def_instrl cfg (Cfg.Node.get_instrs node) acc
let compute_live_instr cfg pdesc s instr =
use_instr cfg pdesc instr (Vset.diff s (def_instr cfg instr Vset.empty))
let compute_live_instrl cfg pdesc instrs livel =
IList.fold_left (compute_live_instr cfg pdesc) livel (IList.rev instrs)
module Worklist = struct
module S = Cfg.NodeSet
let worklist = ref S.empty
let reset _ = worklist := S.empty
let add node = worklist := S.add node !worklist
let pick () =
let min = S.min_elt !worklist in
worklist := S.remove min !worklist;
min
end
(** table of live variables *)
module Table: sig
val reset: unit -> unit
(** variables live after the last instruction in the current node *)
val get_live: Cfg.node -> Vset.t
(** propagate live variables to predecessor nodes *)
val propagate_to_preds: Vset.t -> Cfg.node list -> unit
val iter: Vset.t -> (Cfg.node -> Vset.t -> Vset.t -> unit) -> unit
end = struct
module H = Cfg.NodeHash
let table = H.create 1024
let reset _ = H.clear table
let get_live node = try H.find table node with Not_found -> Vset.empty
let replace node set = H.replace table node set
let propagate_to_preds set preds =
let do_node node =
try
let oldset = H.find table node in
let newset = Vset.union set oldset in
replace node newset;
if not (Vset.equal oldset newset) then Worklist.add node
with Not_found ->
replace node set; Worklist.add node in
IList.iter do_node preds
let iter init f =
let get_live_preds init node = (** nodes live at predecessors *)
match AllPreds.get_preds node with
| [] -> init
| preds -> IList.fold_left Vset.union Vset.empty (IList.map get_live preds) in
H.iter (fun node live -> f node (get_live_preds init node) live) table
end
(** Compute condidate nullable variables amongst formals and locals *)
let compute_candidates procdesc : Vset.t * (Vset.t -> Vset.elt list) =
let candidates = ref Vset.empty in
let struct_array_cand = ref Vset.empty in
let typ_is_struct_array = function
| Sil.Tstruct _ | Sil.Tarray _ -> true
| _ -> false in
let add_vi (pvar, typ) =
let pv = Pvar.mk pvar (Cfg.Procdesc.get_proc_name procdesc) in
candidates := Vset.add pv !candidates;
if typ_is_struct_array typ then struct_array_cand := Vset.add pv !struct_array_cand in
IList.iter add_vi (Cfg.Procdesc.get_formals procdesc);
IList.iter add_vi (Cfg.Procdesc.get_locals procdesc);
let get_sorted_candidates vs =
let priority, no_pri =
IList.partition
(fun pv -> Vset.mem pv !struct_array_cand)
(Vset.elements vs) in
IList.rev_append (IList.rev priority) no_pri in
!candidates, get_sorted_candidates
(** Construct a table wich associates to each node a set of live variables *)
let analyze_proc cfg pdesc cand =
let exit_node = Cfg.Procdesc.get_exit_node pdesc in
Worklist.reset ();
Table.reset ();
Worklist.add exit_node;
try
while true do
let node = Worklist.pick () in
let curr_live = Table.get_live node in
let preds = AllPreds.get_preds node in
let live_at_predecessors =
match Cfg.Node.get_kind node with
| Cfg.Node.Start_node _
| Cfg.Node.Exit_node _
| Cfg.Node.Join_node
| Cfg.Node.Skip_node _ -> curr_live
| Cfg.Node.Prune_node _
| Cfg.Node.Stmt_node _ ->
compute_live_instrl cfg pdesc (Cfg.Node.get_instrs node) curr_live in
Table.propagate_to_preds (Vset.inter live_at_predecessors cand) preds
done
with Not_found -> ()
(* Instruction i is nullifying a block variable *)
let is_block_nullify i =
match i with
| Sil.Nullify(pvar, _) -> Sil.is_block_pvar pvar
| _ -> false
(** Add nullify instructions to the node given dead program variables *)
let node_add_nullify_instrs n dead_vars_after dead_vars_before =
let loc = Cfg.Node.get_last_loc n in
let move_tmp_pvars_first pvars =
let pvars_tmp, pvars_notmp = IList.partition Errdesc.pvar_is_frontend_tmp pvars in
pvars_tmp @ pvars_notmp in
let instrs_after =
IList.map
(fun pvar -> Sil.Nullify (pvar, loc))
(move_tmp_pvars_first dead_vars_after) in
let instrs_before =
IList.map
(fun pvar -> Sil.Nullify (pvar, loc))
(move_tmp_pvars_first dead_vars_before) in
(* Nullify(bloc_var,_,true) can be placed in the middle
of the block because when we add this instruction*)
(* we don't have already all the instructions of the node.
Here we reorder the instructions to move *)
(* nullification of blocks at the end of existing instructions. *)
let block_nullify, no_block_nullify = IList.partition is_block_nullify (Cfg.Node.get_instrs n) in
Cfg.Node.replace_instrs n (no_block_nullify @ block_nullify);
Cfg.Node.append_instrs n instrs_after;
Cfg.Node.prepend_instrs n instrs_before
(** return true if the node does not assign any variables *)
let node_assigns_no_variables cfg node =
let instrs = Cfg.Node.get_instrs node in
let assign_set = def_instrl cfg instrs (Vset.empty) in
Vset.is_empty assign_set
(** Set the dead variables of a node, by default as dead_after.
If the node is a prune or a join node, propagate as dead_before in the successors *)
let add_dead_pvars_after_conditionals_join cfg n deads =
(* L.out " node %d: %a@." (Cfg.Node.get_id n) (Sil.pp_list pe_text) deads; *)
let seen = ref Cfg.NodeSet.empty in
let rec add_after_prune_join is_after node =
if Cfg.NodeSet.mem node !seen (* gone through a loop in the cfg *)
then Cfg.Node.set_dead_pvars n true deads
else
begin
seen := Cfg.NodeSet.add node !seen;
let node_is_exit n = match Cfg.Node.get_kind n with
| Cfg.Node.Exit_node _ -> true
| _ -> false in
let next_is_exit n = match Cfg.Node.get_succs n with
| [n'] -> node_is_exit n'
| _ -> false in
match Cfg.Node.get_kind node with
| Cfg.Node.Prune_node _
| Cfg.Node.Join_node
when node_assigns_no_variables cfg node && not (next_is_exit node) ->
(* cannot push nullify instructions after an assignment,
as they could nullify the same variable *)
let succs = Cfg.Node.get_succs node in
IList.iter (add_after_prune_join false) succs
| _ ->
let new_dead_pvs =
let old_pvs = Cfg.Node.get_dead_pvars node is_after in
let pv_is_new pv = not (IList.exists (Pvar.equal pv) old_pvs) in
(IList.filter pv_is_new deads) @ old_pvs in
Cfg.Node.set_dead_pvars node is_after new_dead_pvs
end in
add_after_prune_join true n
(** Find the set of dead variables for the procedure pname and add nullify instructions.
The variables whose addresses may be taken are only considered just before the exit node. *)
let analyze_and_annotate_proc cfg tenv pname pdesc =
let exit_node = Cfg.Procdesc.get_exit_node pdesc in
let exit_node_is_succ node =
match Cfg.Node.get_succs node with
| [en] -> Cfg.Node.equal en exit_node
| _ -> false in
let cand, get_sorted_cand = compute_candidates pdesc in
let addr_taken_vars =
if !Config.curr_language = Config.Java
then Vset.empty
else
match AddressTaken.Analyzer.compute_post (ProcData.make_default pdesc tenv) with
| Some post -> post
| None -> Vset.empty in
analyze_proc cfg pdesc cand;
let dead_pvars_added = ref 0 in
let dead_pvars_limit = 100000 in
let incr_dead_pvars_added pvars =
let num = IList.length pvars in
dead_pvars_added := num + !dead_pvars_added;
if !dead_pvars_added > dead_pvars_limit && !dead_pvars_added - num <= dead_pvars_limit
then
L.err "WARNING: liveness: more than %d dead pvars added in procedure %a, stopping@."
dead_pvars_limit Procname.pp pname in
Table.iter cand (fun n live_at_predecessors live_current -> (* set dead variables on nodes *)
(* live before, or assigned to *)
let nonnull_pvars = Vset.inter (def_node cfg n live_at_predecessors) cand in
(* only nullify when variables become live *)
let dead_pvars = Vset.diff nonnull_pvars live_current in
let dead_pvars_no_addr_taken = get_sorted_cand (Vset.diff dead_pvars addr_taken_vars) in
let dead_pvars_to_add =
if exit_node_is_succ n (* add dead address taken vars just before the exit node *)
then dead_pvars_no_addr_taken @ (get_sorted_cand (Vset.inter cand addr_taken_vars))
else dead_pvars_no_addr_taken in
incr_dead_pvars_added dead_pvars_to_add;
if !dead_pvars_added < dead_pvars_limit
then add_dead_pvars_after_conditionals_join cfg n dead_pvars_to_add);
IList.iter
(fun n -> (* generate nullify instructions *)
match Cfg.Node.get_kind n with
| Cfg.Node.Start_node _ ->
(* avoid nullifying declared locals/params *)
()
| _ ->
let dead_pvs_after = Cfg.Node.get_dead_pvars n true in
let dead_pvs_before = Cfg.Node.get_dead_pvars n false in
node_add_nullify_instrs n dead_pvs_after dead_pvs_before)
(Cfg.Procdesc.get_nodes pdesc);
Table.reset ()
(** mutate the cfg/cg to add dynamic dispatch handling *)
let add_dispatch_calls cfg cg tenv f_translate_typ_opt =
let pname_translate_types pname =
@ -493,7 +167,6 @@ module NullifyTransferFunctions = struct
failwith "Should not add nullify instructions before running nullify analysis!"
end
module NullifyAnalysis =
AbstractInterpreter.Make
(ProcCfg.Exceptional)
@ -560,17 +233,7 @@ let add_nullify_instrs tenv _ pdesc =
let exit_node = ProcCfg.Exceptional.exit_node nullify_proc_cfg in
node_add_nullify_instructions exit_node (AddressTaken.Domain.elements address_taken_vars)
let old_nullify_analysis = false
let doit ?(f_translate_typ=None) cfg cg tenv =
if old_nullify_analysis
then
begin
AllPreds.mk_table cfg;
Cfg.iter_proc_desc cfg (analyze_and_annotate_proc cfg tenv);
AllPreds.clear_table ()
end
else
Cfg.iter_proc_desc cfg (add_nullify_instrs tenv);
if !Config.curr_language = Config.Java
then add_dispatch_calls cfg cg tenv f_translate_typ;

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