<s>
Sparse	B-Application
is	O
a	O
computer	O
software	O
tool	O
designed	O
to	O
find	O
possible	O
coding	O
faults	O
in	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
Unlike	O
other	B-Application
such	I-Application
tools	I-Application
,	O
this	O
static	O
analysis	O
tool	O
was	O
initially	O
designed	O
to	O
only	O
flag	O
constructs	O
that	O
were	O
likely	O
to	O
be	O
of	O
interest	O
to	O
kernel	B-Operating_System
developers	O
,	O
such	O
as	O
the	O
mixing	O
of	O
pointers	O
to	O
user	O
and	O
kernel	B-Operating_System
address	B-General_Concept
spaces	I-General_Concept
.	O
</s>
<s>
Sparse	B-Application
checks	O
for	O
known	O
problems	O
and	O
allows	O
the	O
developer	O
to	O
include	O
annotations	O
in	O
the	O
code	O
that	O
convey	O
information	O
about	O
data	O
types	O
,	O
such	O
as	O
the	O
address	B-General_Concept
space	I-General_Concept
that	O
pointers	O
point	O
to	O
and	O
the	O
locks	O
that	O
a	O
function	O
acquires	O
or	O
releases	O
.	O
</s>
<s>
Linus	O
Torvalds	O
started	O
writing	O
Sparse	B-Application
in	O
2003	O
.	O
</s>
<s>
Sparse	B-Application
is	O
released	O
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
Some	O
of	O
the	O
checks	O
performed	O
by	O
Sparse	B-Application
require	O
annotating	O
the	O
source	O
code	O
using	O
the	O
__attribute__	O
GCC	B-Application
extension	O
,	O
or	O
the	O
Sparse-specific	O
__context__	O
specifier	O
.	O
</s>
<s>
Sparse	B-Application
defines	O
the	O
following	O
list	O
of	O
attributes	O
:	O
</s>
<s>
The	O
Linux	B-Operating_System
kernel	I-Operating_System
defines	O
the	O
following	O
short	O
forms	O
as	O
pre-processor	O
macros	O
in	O
files	O
and	O
(	O
when	O
building	O
without	O
the	O
__CHECKER__	O
flag	O
,	O
all	O
these	O
annotations	O
are	O
removed	O
from	O
the	O
code	O
)	O
:	O
</s>
<s>
However	O
,	O
the	O
C	B-Language
language	I-Language
does	O
not	O
allow	O
to	O
specify	O
that	O
variables	O
of	O
these	O
types	O
should	O
not	O
be	O
mixed	O
.	O
</s>
<s>
The	O
bitwise	O
attribute	O
is	O
used	O
to	O
mark	O
these	O
types	O
as	O
restricted	O
,	O
so	O
Sparse	B-Application
will	O
give	O
a	O
warning	O
if	O
variables	O
of	O
these	O
types	O
or	O
other	O
integer	O
variables	O
are	O
mixed	O
:	O
</s>
<s>
To	O
mark	O
valid	O
conversions	O
between	O
restricted	O
types	O
,	O
a	O
casting	O
with	O
the	O
force	O
attribute	O
is	O
used	O
to	O
avoid	O
Sparse	B-Application
giving	O
a	O
warning	O
.	O
</s>
