Extending analysis to parametric case

Reviewed By: mbouaziz

Differential Revision: D7179463

fbshipit-source-id: 1711a0e

infer/src/bufferoverrun/bufferOverrunChecker.ml

@@ -308,6 +308,8 @@ end
 module Analyzer = AbstractInterpreter.Make (ProcCfg.Normal) (TransferFunctions)
 module CFG = Analyzer.TransferFunctions.CFG
 
+type invariant_map = Analyzer.invariant_map
+
 module Report = struct
   (* I'd like to avoid rebuilding this :(
     Everything depend on CFG only because of `get_allocsite` *)
@@ -543,6 +545,13 @@ module Report = struct
     PO.ConditionSet.check_all ~report cond_set
 end
 
+let compute_invariant_map : Callbacks.proc_callback_args -> Analyzer.invariant_map =
+ fun {proc_desc; tenv; get_proc_desc} ->
+  Preanal.do_preanalysis proc_desc tenv ;
+  let pdata = ProcData.make proc_desc tenv get_proc_desc in
+  Analyzer.exec_pdesc ~initial:Dom.Mem.init pdata
+
+
 let extract_post inv_map node =
   let id = CFG.id node in
   Analyzer.extract_post id inv_map

infer/src/bufferoverrun/bufferOverrunChecker.mli

@@ -10,3 +10,9 @@
 open! IStd
 
 val checker : Callbacks.proc_callback_t
+
+type invariant_map
+
+val compute_invariant_map : Callbacks.proc_callback_args -> invariant_map
+
+val extract_post : invariant_map -> Procdesc.Node.t -> BufferOverrunDomain.Mem.astate option

infer/src/checkers/cost.ml

@@ -38,9 +38,7 @@ module TransferFunctionsSemantics (CFG : ProcCfg.S) = struct
   module CFG = CFG
   module Domain = CostDomain.SemanticDomain
 
-  type extras = ProcData.no_extras
+  let _exec_instr ((env, alias) as astate: Domain.astate) {ProcData.tenv} _ instr =
-
-  let exec_instr ((env, alias) as astate: Domain.astate) {ProcData.tenv} _ instr =
     let astate' =
       match instr with
       | Sil.Store (lhs, {Typ.desc= Tint _}, rhs, _) ->
@@ -86,9 +84,6 @@ module TransferFunctionsSemantics (CFG : ProcCfg.S) = struct
     astate'
 end
 
-(* TODO: use inferbo for the parametric version *)
-module AnalyzerSemantics = AbstractInterpreter.Make (CFG) (TransferFunctionsSemantics)
-
 (* Map associating to each node a bound on the number of times it can be executed.
    This bound is computed using environments (map: val -> values), using the following
    observation: the number of environments associated with a program point is an upperbound
@@ -111,34 +106,71 @@ module BoundMap = struct
     L.(debug Analysis Medium) "@\n******* END Bound Map **** @\n\n"
 
 
+  let convert (mem: BufferOverrunDomain.Mem.astate) : CostDomain.EnvDomainBO.astate =
+    let open AbstractDomain.Types in
+    match mem with
+    | Bottom ->
+        assert false
+    | NonBottom {BufferOverrunDomain.MemReach.heap} ->
+        let env =
+          BufferOverrunDomain.Heap.fold
+            (fun loc data acc ->
+              match loc with
+              | AbsLoc.Loc.Var Var.LogicalVar id ->
+                  let key = Exp.Var id in
+                  CostDomain.EnvDomain.add key (BufferOverrunDomain.Val.get_itv data) acc
+              | AbsLoc.Loc.Var Var.ProgramVar v ->
+                  let key = Exp.Lvar v in
+                  CostDomain.EnvDomain.add key (BufferOverrunDomain.Val.get_itv data) acc
+              | _ ->
+                  acc )
+            heap CostDomain.EnvDomainBO.empty
+        in
+        env
+
+
   let compute_upperbound_map cfg invariant_map =
+    let range itv =
+      let rng = Itv._range itv in
+      match Itv.Bound.is_const rng with
+      | Some r ->
+          CostDomain.Cost.nth r
+      | _ ->
+          (* TODO: write code for the non constant case *)
+          L.(debug Analysis Medium)
+            "@\n [Range computation]: Can't determine a range for itv = %a. Returning Top@\n"
+            Itv.Bound.pp rng ;
+          Top
+    in
     let compute_node_upper_bound node =
       let node_id = Procdesc.Node.get_id node in
+      let entry_mem_opt = BufferOverrunChecker.extract_post invariant_map node in
       match Procdesc.Node.get_kind node with
       | Procdesc.Node.Exit_node _ ->
           bound_map := Int.Map.set !bound_map ~key:(node_id :> int) ~data:CostDomain.Cost.one
       | _ ->
-        match AnalyzerSemantics.extract_post node_id invariant_map with
+        match entry_mem_opt with
-        | Some (env, _) ->
+        | Some entry_mem ->
+            let env = convert entry_mem in
             (* bound = env(v1) *... * env(vn) *)
             let bound =
-              CostDomain.EnvDomain.fold
+              CostDomain.EnvDomainBO.fold
                 (fun exp itv acc ->
                   let itv' =
                     match exp with
                     | Exp.Lvar _ ->
                         itv
                     | Exp.Var _ ->
-                        CostDomain.ItvPureCost.of_int 1
+                        Itv.one
                     (* For temp var we give [1,1] so it doesn't count*)
                     | _ ->
                         assert false
                   in
-                  let itv_range = CostDomain.ItvPureCost.range itv' in
+                  let itv_range = range itv' in
                   L.(debug Analysis Medium)
-                    "@\n>>>LB =%a and UB =%a UB-LB =%a for node = %i @\n\n" CostDomain.Cost.pp
+                    "@\n>>>For node = %i :   itv=%a  range=%a  @\n\n"
-                    (fst itv') CostDomain.Cost.pp (snd itv') CostDomain.Cost.pp itv_range
+                    (node_id :> int)
-                    (node_id :> int) ;
+                    Itv.pp itv' CostDomain.Cost.pp itv_range ;
                   CostDomain.Cost.mult acc itv_range )
                 env CostDomain.Cost.one
             in
@@ -430,6 +462,7 @@ module TransferFunctionsNodesBasicCost (CFG : ProcCfg.S) = struct
 end
 
 module AnalyzerNodesBasicCost = AbstractInterpreter.Make (CFG) (TransferFunctionsNodesBasicCost)
+module RepSet = AbstractDomain.FiniteSet (Int)
 
 (* Calculate the final Worst Case Execution Time predicted for each node.
    It uses the basic cost of the nodes (computed previously by AnalyzerNodesBasicCost)
@@ -437,93 +470,114 @@ module AnalyzerNodesBasicCost = AbstractInterpreter.Make (CFG) (TransferFunction
 *)
 module TransferFunctionsWCET (CFG : ProcCfg.S) = struct
   module CFG = CFG
-  module Domain = CostDomain.CostSingleIteration
+  module CSI = CostDomain.CostSingleIteration
+  module Domain = AbstractDomain.Pair (CSI) (RepSet)
 
   type extras =
     (* extras: (map with basic costs, min trees map, summary ) *)
     AnalyzerNodesBasicCost.invariant_map * CostDomain.Cost.astate Int.Map.t * Specs.summary
 
-  let report_cost summary instr cost =
+  let report_cost summary instr cost nid reported_so_far =
+    match cost with
+    | Top ->
+        (cost, reported_so_far)
+        (* We don't report when the cost Top as it corresponds to 'don't know'*)
+    | _ ->
+        let above_expensive_threshold = not (CSI.( <= ) ~lhs:cost ~rhs:expensive_threshold) in
         match instr with
-    | Sil.Call (_, _, _, loc, _) when not (Domain.( <= ) ~lhs:cost ~rhs:expensive_threshold) ->
+        | Sil.Call (_, _, _, loc, _) when above_expensive_threshold ->
             let ltr = [Errlog.make_trace_element 0 loc "" []] in
             let message =
               F.asprintf
                 "This instruction is expensive (estimated cost %a). Its execution time is likely \
-             above the acceptable treshold " Domain.pp cost
+                 above the acceptable treshold " CSI.pp cost
             in
             let exn =
               Exceptions.Checkers
                 (IssueType.expensive_execution_time_call, Localise.verbatim_desc message)
             in
-        Reporting.log_error summary ~loc ~ltr exn
+            Reporting.log_error summary ~loc ~ltr exn ;
+            (cost, RepSet.add nid reported_so_far)
         | Sil.Load (_, _, _, loc)
         | Sil.Store (_, _, _, loc)
         | Sil.Call (_, _, _, loc, _)
         | Sil.Prune (_, loc, _, _)
-      when not (Domain.( <= ) ~lhs:cost ~rhs:expensive_threshold) ->
+          when above_expensive_threshold ->
             let ltr = [Errlog.make_trace_element 0 loc "" []] in
             let message =
               F.asprintf
                 "The execution time from the beginning of the function is above the acceptable \
-             treshold (estimated cost %a up to here)" Domain.pp cost
+                 treshold (estimated cost %a up to here)" CSI.pp cost
             in
             let exn =
               Exceptions.Checkers
                 (IssueType.expensive_execution_time_call, Localise.verbatim_desc message)
             in
-        Reporting.log_error summary ~loc ~ltr exn
+            Reporting.log_error summary ~loc ~ltr exn ;
+            (cost, RepSet.add nid reported_so_far)
         | _ ->
-        ()
+            (cost, reported_so_far)
+
+
+  (* get a list of nodes and check if we have already reported for at
+   least one of them. In that case no need to report again. *)
+  let should_report preds reported_so_far =
+    List.for_all
+      ~f:(fun n ->
+        let n_id = (Procdesc.Node.get_id n :> int) in
+        not (RepSet.mem n_id reported_so_far) )
+      preds
 
 
-  let exec_instr (_: Domain.astate) {ProcData.extras} (node: CFG.node) instr : Domain.astate =
+  let exec_instr (astate: Domain.astate) {ProcData.extras} (node: CFG.node) instr : Domain.astate =
     let invariant_map_cost, trees, summary = extras in
-    let map_cost m : Domain.astate =
+    let und_node = CFG.underlying_node node in
+    let node_id = Procdesc.Node.get_id und_node in
+    let preds = Procdesc.Node.get_preds und_node in
+    let map_cost m : CSI.astate =
       CostDomain.NodeInstructionToCostMap.fold
         (fun (nid, idx) c acc ->
           match Int.Map.find trees nid with
           | Some t ->
-              let c_node = Domain.mult c t in
+              let c_node = CSI.mult c t in
               L.(debug Analysis Medium)
-                "@\n  [AnalizerWCTE] Adding cost: (%i,%i) --> c =%a  t = %a @\n" nid idx Domain.pp
+                "@\n  [AnalizerWCTE] Adding cost: (%i,%i) --> c =%a  t = %a @\n" nid idx CSI.pp c
-                c Domain.pp t ;
+                CSI.pp t ;
-              let c_node' = Domain.plus acc c_node in
+              let c_node' = CSI.plus acc c_node in
               L.(debug Analysis Medium)
                 "@\n  [AnalizerWCTE] Adding cost: (%i,%i) --> c_node=%a  cost = %a @\n" nid idx
-                Domain.pp c_node Domain.pp c_node' ;
+                CSI.pp c_node CSI.pp c_node' ;
-              report_cost summary instr c_node' ;
               c_node'
           | _ ->
               assert false )
-        m Domain.zero
+        m CSI.zero
     in
-    let astate' =
+    let cost_node =
-      let node_id = Procdesc.Node.get_id (CFG.underlying_node node) in
       match AnalyzerNodesBasicCost.extract_post node_id invariant_map_cost with
       | Some node_map ->
           L.(debug Analysis Medium)
             "@\n AnalizerWCTE] Final map for node: %a @\n" Procdesc.Node.pp_id node_id ;
-          let map_cost = map_cost node_map in
+          map_cost node_map
-          map_cost
       | _ ->
           assert false
     in
     L.(debug Analysis Medium)
-      "@\n>>>AnalizerWCTE] Instr: %a   Cost: %a@\n" (Sil.pp_instr Pp.text) instr Domain.pp astate' ;
+      "@\n>>>AnalizerWCTE] Instr: %a   Cost: %a@\n" (Sil.pp_instr Pp.text) instr CSI.pp cost_node ;
+    let reported_so_far = snd astate in
+    let astate' =
+      if should_report (und_node :: preds) reported_so_far then
+        report_cost summary instr cost_node (node_id :> int) reported_so_far
+      else (cost_node, reported_so_far)
+    in
     astate'
 end
 
 module AnalyzerWCET = AbstractInterpreter.Make (CFG) (TransferFunctionsWCET)
 
-let checker {Callbacks.tenv; summary; proc_desc} : Specs.summary =
+let checker ({Callbacks.tenv; summary; proc_desc} as proc_callback_args) : Specs.summary =
   let cfg = CFG.from_pdesc proc_desc in
   (* computes the semantics: node -> (environment, alias map) *)
-  let semantics_invariant_map =
+  let semantics_invariant_map = BufferOverrunChecker.compute_invariant_map proc_callback_args in
-    AnalyzerSemantics.exec_cfg cfg
-      (ProcData.make_default proc_desc tenv)
-      ~initial:(CostDomain.EnvDomain.empty, []) ~debug:true
-  in
   (* given the semantics computes the upper bound on the number of times a node could be executed *)
   BoundMap.compute_upperbound_map cfg semantics_invariant_map ;
   let constraints = StructuralConstraints.compute_structural_constraints cfg in
@@ -542,14 +596,15 @@ let checker {Callbacks.tenv; summary; proc_desc} : Specs.summary =
       (ProcData.make_default proc_desc tenv)
       ~initial:CostDomain.NodeInstructionToCostMap.empty ~debug:true
   in
+  let initWCET = (CostDomain.CostSingleIteration.zero, RepSet.empty) in
   let invariant_map_WCETFinal =
     (* Final map with nodes cost *)
     AnalyzerWCET.exec_cfg cfg
       (ProcData.make proc_desc tenv (invariant_map_NodesBasicCost, trees_valuation, summary))
-      ~initial:CostDomain.CostSingleIteration.zero ~debug:true
+      ~initial:initWCET ~debug:true
   in
   match AnalyzerWCET.extract_post (CFG.id (CFG.exit_node cfg)) invariant_map_WCETFinal with
-  | Some exit_cost ->
+  | Some (exit_cost, _) ->
       Summary.update_summary {post= exit_cost} summary
   | None ->
       if Procdesc.Node.get_succs (Procdesc.get_start_node proc_desc) <> [] then (

infer/src/checkers/costDomain.ml

@@ -187,6 +187,7 @@ module ItvPureCost = struct
 end
 
 module EnvDomain = AbstractDomain.Map (Exp) (ItvPureCost)
+module EnvDomainBO = AbstractDomain.Map (Exp) (Itv)
 
 module SemanticDomain = struct
   include AbstractDomain.Pair (EnvDomain) (Alias)
@@ -346,9 +347,6 @@ module SemanticDomain = struct
     | _ ->
         L.die InternalError " @\n Incomplete Sem function. Dies with e= %a @\n" Exp.pp e
 
-
-  let pp fmt (env, alias) =
-    F.fprintf fmt "@\n env: %a @\n alias: [ %a ] @\n" EnvDomain.pp env Alias.pp alias
 end
 
 type summary = {post: Cost.astate}

infer/tests/codetoanalyze/c/performance/Makefile

@@ -0,0 +1,20 @@
+# Copyright (c) 2018 - present Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+TESTS_DIR = ../../..
+
+ANALYZER = checkers
+# see explanations in cpp/errors/Makefile for the custom isystem
+CLANG_OPTIONS = -c
+INFER_OPTIONS = --cost-only --debug-exceptions --project-root $(TESTS_DIR)
+INFERPRINT_OPTIONS = --issues-tests
+
+SOURCES = $(wildcard *.c)
+
+include $(TESTS_DIR)/clang.make
+
+infer-out/report.json: $(MAKEFILE_LIST)

infer/tests/codetoanalyze/c/performance/cost_test.c

@@ -6,7 +6,8 @@
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
  */
-int foo() {
+// Cost: 5
+int foo_OK() {
   int i, j;
   i = 17;
   j = 31;
@@ -14,31 +15,34 @@ int foo() {
   return i + j + 3 + 7;
 }
 
-int bar() {
+// Cost: 17
+int bar_OK() {
 
   int j = 0;
 
   j++;
   j++;
   j++;
-  j = foo();
+  j = foo_OK();
   j++;
 
   return j;
 }
 
-int cond(int i) {
+// Cost: 25
+int cond_OK(int i) {
   int x;
 
   if (i < 0) {
-    x = bar();
+    x = bar_OK();
   } else {
     x = 1;
   }
   return x;
 }
 
-void alias() {
+// Cost: 5
+void alias_OK() {
 
   int i, j;
 
@@ -46,7 +50,8 @@ void alias() {
   i = ++i;
 }
 
-void alias2() {
+// Cost: 6
+void alias2_OK() {
 
   int i, j, z;
 
@@ -57,20 +62,45 @@ void alias2() {
   i = z;
 }
 
-int loop0() {
+// Cost: 1004
+int loop0_bad() {
 
   for (int i = 0; i < 100; i++) {
-    alias2();
+    alias2_OK();
   }
   return 0;
 }
 
-int main() {
+// Cost: 1006
+int loop1_bad() {
+
+  int k = 100;
+  for (int i = 0; i < k; i++) {
+    alias2_OK();
+  }
+  return 0;
+}
+
+// This is currently evaluated to Top as the analysis is not powerful enough
+int FN_loop2(int k) {
 
-  int k;
+  for (int i = 0; i < k; i++) {
+    alias2_OK();
+  }
+  return 0;
+}
+
+// Cost: 218
+// Shows that calling many times non expensive function can
+// result in an expensive computation
+int main() {
 
-  cond(2);
+  int k1, k2, k3, k4;
-  k = bar() + foo() * 2;
 
+  cond_OK(2);
+  k1 = bar_OK() + foo_OK() + cond_OK(15) * 2;
+  k2 = bar_OK() + foo_OK() + cond_OK(17) * 3;
+  k3 = bar_OK() + foo_OK() + cond_OK(11) * 3;
+  k4 = bar_OK() + foo_OK() + cond_OK(19) * 3;
   return 0;
 }

infer/tests/codetoanalyze/c/performance/issues.exp

@@ -0,0 +1,7 @@
+codetoanalyze/c/performance/cost_test.c, loop0_bad, 2, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, loop0_bad, 3, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, loop0_bad, 5, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, loop1_bad, 3, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, loop1_bad, 4, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, loop1_bad, 6, EXPENSIVE_EXECUTION_TIME_CALL, []
+codetoanalyze/c/performance/cost_test.c, main, 8, EXPENSIVE_EXECUTION_TIME_CALL, []