Description: CFG Edge

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Each point has edge sets listing neighbors in the CFG. There are two different CFG abstractions: interprocedural and intraprocedural.

Language Module Support: Internal representation for points is available for C/C++ and binary analyses only. For C# and Java analyses, plug-ins that rely on point (and thus CFG edge) properties and relationships will generally not produce useful information.

Each point (PDG_VERTEX) has edge sets listing neighbors in the CFG. There are two different CFG abstractions: interprocedural and intraprocedural.

	Interprocedural CFG	Intraprocedural CFG
Models:	Control flow in the entire project. (A single large graph.)	Control flow within a single function. (One graph per function.)
Edge kinds:	Both interprocedural edges (edges between functions) and intraprocedural edges (edges within functions).	Intraprocedural edges (edges within the function) only; each function call is treated as if it were an atomic operation.
Neighbors:	interprocedural edges	all edges	fine-grained view	coarse-grained view
edges to p	not available	not available	not available	not available
edges from p	cfg-inter-targets	not available	cfg-targets	not available

Interprocedural CFG

Intraprocedural CFG

Models:

Control flow in the entire project.

(A single large graph.)

Control flow within a single function.

(One graph per function.)

Edge kinds:

Both interprocedural edges (edges between functions) and intraprocedural edges (edges within functions).

Intraprocedural edges (edges within the function) only; each function call is treated as if it were an atomic operation.

Neighbors:

interprocedural edges

all edges

fine-grained view

coarse-grained view

edges to p

not available

edges from p

cfg-inter-targets

not available

cfg-targets

not available

For each point p, API functions provide access to:

The available sets of CFG neighbors of p, as shown in the table above.

Information about p's basic block membership, if available (CodeSurfer only):

What is the first vertex in the basic block containing p?
What is the last vertex in the basic block containing p?
Does p belong to the same basic block as point q?

interprocedural CFG	The interprocedural successor of (the last actual parameter of) a function call is the entry of the called function. The successors of an exit are all points to which the function may return. The intraprocedural edge from (the last actual parameter of) a function call to the statement to which the function returns is omitted.
intraprocedural CFG fine-grained view	Vertices are program points. The only successors of (the last actual parameter of) a call to a function are the points to which the called function would return. Successors and predecessors are known as targets and sources, respectively.
intraprocedural CFG coarse-grained view	Vertices are basic blocks, where a basic block is a sequence of consecutive program points in which intraprocedural flow of control can only enter at the first program point and leave at the last program point. Each point has an associated basic block. An edge between two basic blocks is represented as an edge between two representative vertices, one from each block.

interprocedural CFG

The interprocedural successor of (the last actual parameter of) a function call is the entry of the called function.
The successors of an exit are all points to which the function may return.
The intraprocedural edge from (the last actual parameter of) a function call to the statement to which the function returns is omitted.

intraprocedural CFG
fine-grained view

Vertices are program points.
The only successors of (the last actual parameter of) a call to a function are the points to which the called function would return.
Successors and predecessors are known as targets and sources, respectively.

intraprocedural CFG
coarse-grained view

Vertices are basic blocks, where a basic block is a sequence of consecutive program points in which intraprocedural flow of control can only enter at the first program point and leave at the last program point.
Each point has an associated basic block.
An edge between two basic blocks is represented as an edge between two representative vertices, one from each block.

By API implementation:

Language	CFG Edge Functionality and Types Provided By	CFG Edge Type
C++	class point	typedef cfg_edge
Python	class point	pair (point, edge_label)
C	Headers cs_pdg_vertex.h, cs_edge_label.h	typedef cs_cfg_edge

Language

CFG Edge Functionality and Types Provided By

CFG Edge Type

C++

class point

typedef cfg_edge

Python

class point

pair (point, edge_label)

Headers cs_pdg_vertex.h, cs_edge_label.h

typedef cs_cfg_edge

Description: CFG Edge

Overview

API Functionality

More on CFG Edges

Links