[pulse] canonicalise attributes too

Summary:
I... kinda forgot about attributes in D25092158 (ab2813e355), which is probably why
impurity was angry that attributes were sometimes missing. Repare this
by adding together the attributes of all the values that are equal.

Reviewed By: skcho

Differential Revision: D25428405

fbshipit-source-id: e5d55b782

infer/src/pulse/PulseAbductiveDomain.ml

@@ -531,22 +531,27 @@ let incorporate_new_eqs astate new_eqs =
 let canonicalize astate =
   let open SatUnsat.Import in
   let get_var_repr v = PathCondition.get_var_repr astate.path_condition v in
-  let canonicalize_base stack heap =
+  let canonicalize_base stack heap attrs =
     let stack' = BaseStack.canonicalize ~get_var_repr stack in
     (* note: this step also de-registers addresses pointing to empty edges *)
     let+ heap' = BaseMemory.canonicalize ~get_var_repr heap in
-    (stack', heap')
+    let attrs' = BaseAddressAttributes.canonicalize ~get_var_repr attrs in
+    (stack', heap', attrs')
   in
   (* need different functions for pre and post to appease the type system *)
   let canonicalize_pre (pre : PreDomain.t) =
-    let+ stack', heap' = canonicalize_base (pre :> BaseDomain.t).stack (pre :> BaseDomain.t).heap in
-    PreDomain.update ~stack:stack' ~heap:heap' pre
+    let+ stack', heap', attrs' =
+      canonicalize_base (pre :> BaseDomain.t).stack (pre :> BaseDomain.t).heap
+        (pre :> BaseDomain.t).attrs
+    in
+    PreDomain.update ~stack:stack' ~heap:heap' ~attrs:attrs' pre
   in
   let canonicalize_post (post : PostDomain.t) =
-    let+ stack', heap' =
+    let+ stack', heap', attrs' =
       canonicalize_base (post :> BaseDomain.t).stack (post :> BaseDomain.t).heap
+        (post :> BaseDomain.t).attrs
     in
-    PostDomain.update ~stack:stack' ~heap:heap' post
+    PostDomain.update ~stack:stack' ~heap:heap' ~attrs:attrs' post
   in
   let* pre = canonicalize_pre astate.pre in
   let+ post = canonicalize_post astate.post in

infer/src/pulse/PulseBaseAddressAttributes.ml

@@ -130,3 +130,17 @@ let is_end_of_collection address attrs =
 let is_std_vector_reserved address attrs =
   Graph.find_opt address attrs
   |> Option.value_map ~default:false ~f:Attributes.is_std_vector_reserved
+
+
+let canonicalize ~get_var_repr attrs_map =
+  (* TODO: merging attributes together can produce contradictory attributes, eg [MustBeValid] +
+     [Invalid]. We could detect these and abort execution. This is not really restricted to merging
+     as it might be possible to get a contradiction by accident too so maybe here is not the best
+     place to detect these. *)
+  Graph.fold
+    (fun addr attrs g ->
+      if Attributes.is_empty attrs then g
+      else
+        let addr' = get_var_repr addr in
+        add addr' attrs g )
+    attrs_map Graph.empty

infer/src/pulse/PulseBaseAddressAttributes.mli

@@ -54,3 +54,7 @@ val pp : F.formatter -> t -> unit
 val remove_allocation_attr : AbstractValue.t -> t -> t
 
 val initialize : AbstractValue.t -> t -> t
+
+val canonicalize : get_var_repr:(AbstractValue.t -> AbstractValue.t) -> t -> t
+(** merge the attributes of all the variables that are equal according to [get_var_repr] and remove
+    non-canonical variables in favor of their rerpresentative *)