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Module Property_status

module Property_status: sig .. end

Status of properties.

Local status

A local status (shortly, a status) of a property is a status directly set by an emitter. Thus a property may have several distinct status according to who attempts the verification.

Emitting a status

type emitted_status =
| True (*

for each execution path ep from the program entry point to s, the formula (/\_ h) ==> P(ep) is true

*)
| False_if_reachable (*

for each execution path ep from the program entry point to s, the formula (/\_ h) ==> P(ep) is false

*)
| False_and_reachable (*

it exists an execution path ep from the program entry point to s such that the formula (/\_ h) ==> P(ep) is false

*)
| Dont_know (*

any other case

*)

Type of status emitted by analyzers. Each Property is attached to a program point s and implicitly depends on an execution path from the program entry point to s. It also depends on an explicit set of hypotheses H indicating when emitting the property (see function Property_status.emit).

module Emitted_status: Datatype.S  with type t = emitted_status
exception Inconsistent_emitted_status of emitted_status * emitted_status
val emit : Emitter.t ->
       hyps:Property.t list ->
       Property.t -> ?distinct:bool -> emitted_status -> unit

emit e ~hyps p s indicates that the status of p is s, is emitted by e, and is based on the list of hypothesis hyps. If e previously emitted another status s', it must be emitted with the same hypotheses and a consistency check is performed between s and s' and the best (by default the strongest) status is kept. If distinct is true (default is false), then we consider than the given status actually merges several statuses coming from distinct execution paths. The strategy for computing the best status is changed accordingly. One example when ~distinct:true may be required is when emitting a status for a pre-condition of a function f since the status associated to a pre-condition p merges all statuses of p at each callsite of the function f.

val emit_and_get : Emitter.t ->
       hyps:Property.t list ->
       Property.t ->
       ?distinct:bool ->
       emitted_status -> emitted_status

Like Property_status.emit but also returns the computed status.

val logical_consequence : Emitter.t -> Property.t -> Property.t list -> unit

logical_consequence e ppt list indicates that the emitter e considers that ppt is a logical consequence of the conjunction of properties list. Thus it lets the kernel automatically computes it: e must not call functions emit* itself on this property, but the kernel ensures that the status will be up-to-date when getting it.

val legal_dependency_cycle : Emitter.t -> Property.Set.t -> unit

The given properties may define a legal dependency cycle for the given emitter.

val self : State.t

The state which stores the computed status.

Getting a (local) status

type emitter_with_properties = private {
   emitter : Emitter.Usable_emitter.t;
   mutable properties : Property.t list;
   logical_consequence : bool; (*

Is the emitted status automatically inferred?

*)
} 
type inconsistent = private {
   valid : emitter_with_properties list;
   invalid : emitter_with_properties list;
} 
type status = private
| Never_tried (*

Nobody tries to verify the property

*)
| Best of emitted_status * emitter_with_properties list (*

Best(s, l):

  • s: The know more precise status
  • l: who attempt the verification under which hypotheses
*)
| Inconsistent of inconsistent (*

someone locally says the property is valid and someone else says it is invalid: only the consolidated status may conclude.

*)

Type of the local status of a property.

include Datatype.S
val get : Property.t -> status

Iteration on all the individual statuses emitted for the given property.

val iter_on_statuses : (emitter_with_properties ->
        emitted_status -> unit) ->
       Property.t -> unit
val fold_on_statuses : (emitter_with_properties ->
        emitted_status -> 'a -> 'a) ->
       Property.t -> 'a -> 'a

Consolidated status

module Consolidation: sig .. end

Consolidation of a property status according to the (consolidated) status of the hypotheses of the property.

module Feedback: sig .. end

Lighter version than Consolidation

module Consolidation_graph: sig .. end

See the consolidated status of a property in a graph, which all its dependencies and their consolidated status.

Iteration over the registered properties

val iter : (Property.t -> unit) -> unit
val fold : (Property.t -> 'a -> 'a) -> 'a -> 'a
val iter_sorted : cmp:(Property.t -> Property.t -> int) -> (Property.t -> unit) -> unit
val fold_sorted : cmp:(Property.t -> Property.t -> int) -> (Property.t -> 'a -> 'a) -> 'a -> 'a

API not for casual users

val register : Property.t -> unit

Register the given property. It must not be already registered.

val register_property_add_hook : (Property.t -> unit) -> unit

add an hook that will be called for any newly registered property

val remove : Property.t -> unit

Remove the property deeply. Must be called only when removing the corresponding annotation.

val register_property_remove_hook : (Property.t -> unit) -> unit

Add and hook that will be called each time a property is removed.

val merge : old:Property.t list -> Property.t list -> unit

merge old new registers properties in new which are not in old and removes properties in old which are not in new.

val automatically_computed : Property.t -> bool

Is the status of the given property only automatically handled by the kernel?