module Abstract_domain:sig
..end
In EVA, different abstract domains may communicate through alarms, values
and locations.
Alarms report undesirable behaviors that may occur during an execution
of the program. They are defined in Alarmset
, while values and locations
depend on the domain.
Values are numerical and non-relational abstractions of the set of the
possible values of expressions at a program point. Locations are similar
abstractions for memory locations. The main values and locations used
in the analyzer are respectively available in Main_values
and
Main_locations
. Values and locations abstractions are extensible, should
a domain requires new abstractions. Their signature are in
Abstract_value.S
and Abstract_location.S
.
Lvalues and expressions are cooperatively evaluated into locations and values using all the information provided by all domains. These computed values and locations are then available for the domain transformers which model the action of statements on abstract states. However, a domain could ignore this mechanism; its values and locations should then be the unit type.
This file gathers the definition of the module types for an abstract domain.
The module type Abstract_domain.S
requires all the functions to be implemented to define
the abstract semantics of a domain, divided in three categories:
Abstract_domain.Lattice
gives a semi-lattice structure to the abstract states;Abstract_domain.Queries
extracts information from a state, by giving a value to an
expression.Abstract_domain.Transfer
are the transfer functions of the domain for assignments,
assumptions and function calls. It is a functor from a Abstract_domain.Valuation
module, which are maps containing all locations and values computed by
the evaluation of the expressions involved in the considered statement.Abstract_domain.S_with_Structure
is Abstract_domain.S
, plus a special OCaml value
describing the internal structure of the domain and identifying it.
This structure enables automatic accessors to the domain when
combined to others. See Structure
for details.
Abstract_domain.S_with_Structure
is the interface to implement in order to introduce
a now domain in EVA.
The module type Abstract_domain.Internal
contains some other functionalities needed by
the analyzer, but that can be automatically generated from the previous
one. The functor Domain_builder.Complete
produces an Abstract_domain.Internal
module
from a Abstract_domain.S_with_Structure
one.
Abstract_domain.Internal
modules can then be lifted on more general values and locations
through Domain_lift.Make
, and be combined through Domain_product.Make
.
Finally, Abstract_domain.External
is the type of the final modules built and used by EVA.
It contains the generic accessors to specific domains, described in
Abstract_domain.Interface
.
module type Lattice =sig
..end
module type Queries =sig
..end
module type Transfer =sig
..end
module type Logic =sig
..end
module type Valuation =sig
..end
module type S =sig
..end
type'a
key ='a Structure.Key_Domain.k
type'a
structure ='a Structure.Key_Domain.structure
=
| |
Void : |
| |
Leaf : |
| |
Node : |
let key = Structure.Key_Domain.create_key "name_of_the_domain";;
let structure = Leaf key;;
Then, the key should be exported by the domain, to allow the use of the
functions defined in the Abstract_domain.Interface
interface below.
A compound domain may use the Node
constructor to provide a separate
access to each of its parts.
A domain can also use the Void
constructor to prevent access to itself.
module type S_with_Structure =sig
..end
module type Interface =sig
..end
module type Store =sig
..end
module type Internal =sig
..end
module type External =sig
..end