package bap-std
Control Flow Graph with a machine basic block as a node.
Graph is mathematical data structure that is used to represent relations between elements of a set. Usually, graph is defined as an ordered pair of two sets - a set of vertices and a set of edges that is a 2-subset of the set of nodes,
G = (V,E).
In Graphlib vertices (called nodes in our parlance) and edges are labeled. That means that we can associate data with edges and nodes. Thus graph should be considered as an associative data structure. And from mathematics perspective graph is represented as an ordered 6-tuple, consisting of a set of nodes, edges, node labels, edge labels, and two functions that maps nodes and edges to their corresponding labels:
G = (N, E, N', E', ν : N -> N', ε : E -> E'),
where set E
is a subset of N × N
.
With this general framework an unlabeled graph can be represented as:
G = (N, E, N, E, ν = λx.x, ε = λx.x)
Another possible representation of an unlabeled graph would be:
G = (N, E, {u}, {v}, ν = λx.u, ε = λx.v).
Implementations are free to choose any suitable representation of graph data structure, if it conforms to the graph signature and all operations follows the described semantics and properties of a graph structure are preserved.
The axiomatic semantics of operations on a graph is described by a set of postconditions. To describe the semantics of an operation in terms of input and output arguments, we project graphs to its fields with the following notation <field>(<graph>)
, e.g., N(g)
is a set of nodes of graph g
.
Only the strongest postcondition is specified, e.g., if it is specified that νn = l
, then it also means that
n ∈ N ∧ ∃u((u,v) ∈ E ∨ (v,u) ∈ E) ∧ l ∈ N' ∧ ...
In other words the structure G
of the graph G is an invariant that is always preserved.
type t = cfg
type of graph
type node = block
type of nodes
Graph nodes.
module Edge :
Graphlib.Std.Edge
with type graph = t
and type t = edge
and type node = node
with type label = edge
Graph edges
val empty : t
empty
is an empty graph
val nodes : t -> node Regular.Std.seq
nodes g
returns all nodes of graph g
in an unspecified order
val edges : t -> edge Regular.Std.seq
edges g
returns all edges of graph g
in an unspecified order
val number_of_edges : t -> int
number_of_edges g
returns the size of a graph g
.
val number_of_nodes : t -> int
number_of_nodes g
returns the order of a graph g
All graphs provides a common interface for any opaque data structure
include Regular.Std.Opaque.S with type t := t
include Core_kernel.Comparable.S with type t := t
include Base.Comparable.S with type t := t
val comparator : (t, comparator_witness) Base__Comparator.comparator
module Map :
Core_kernel.Map.S
with type Key.t = t
with type Key.comparator_witness = comparator_witness
module Set :
Core_kernel.Set.S
with type Elt.t = t
with type Elt.comparator_witness = comparator_witness
include Core_kernel.Hashable.S with type t := t
module Table : Core_kernel.Hashtbl.S with type key = t
module Hash_set : Core_kernel.Hash_set.S with type elt = t
module Hash_queue : Core_kernel.Hash_queue.S with type key = t
All graphs are printable.
include Regular.Std.Printable.S with type t := t
val to_string : t -> string
to_string x
returns a human-readable representation of x
val str : unit -> t -> string
str () t
is formatted output function that matches "%a" conversion format specifier in functions, that prints to string, e.g., sprintf
, failwithf
, errorf
and, surprisingly all Lwt
printing function, including Lwt_io.printf
and logging (or any other function with type ('a,unit,string,...) formatN`. Example:
Or_error.errorf "type %a is not valid for %a"
Type.str ty Exp.str exp
val pps : unit -> t -> string
synonym for str
val ppo : Core_kernel.Out_channel.t -> t -> unit
will print to a standard output_channel
, useful for using in printf
, fprintf
, etc.
val pp_seq : Stdlib.Format.formatter -> t Core_kernel.Sequence.t -> unit
prints a sequence of values of type t