Contents

class access_path

An access path describes a memory location as a sequence of steps from some base symbol , with each step represented by a access_path object.

For example, suppose we have the following declarations.

char *p;
char **pp;
char A[10];
float f;
struct mys {
   int i;
   double d;
   };
struct mys s;
struct mys *sp;

We can describe various code artifacts in terms of base and access path as shown in the following table.

Code artifact base symbol access path
f f []
p[4] p [ access_path.offset_in_bits(), access_path.star() ]
&p p [ access_path.addr() ]
(*pp)[4] pp [ access_path.offset_in_bits(), access_path.star(), access_path.star() ]
*(pp[4]) pp [ access_path.star(), access_path.offset_in_bits(), access_path.star() ]
A[5] A [ access_path.offset_in_bits() ]
s.d s [ access_path.offset_in_bits() ]
ps->d ps [ access_path.offset_in_bits(), access_path.star() ]

Where:

  • the d field is offset 32 bits from the start of s / *ps, assuming 32-bit integers
  • 40 is 5*8, and a char is 8 bits
  • assuming 32-bit pointers: 4*32 = 128
  • 32 is 4*8, and a char is 8 bits

Note that the access operator access_path.addr() can only ever appear in a singleton access path. No other access paths containing the address operator correspond to legal expressions.

access_path Members

Constructors none
Static Methods addr(), offset_in_bits(), star()
Methods __repr__(), __str__()

access_path Details

class cs.access_path

An access path describes a memory location as a sequence of steps from some base symbol , with each step represented by a access_path object.

static addr()

Get a new access path element corresponding to the address (&) operator.

Return type:access_path
Returns:The newly created access_path element. 
>>> access_path.addr()
<cs.access_path &>
static offset_in_bits(off)

Get a new access path element corresponding to the offset ([]) operator, with offset as specified.

Parameters:off (int) – The offset, in bits.
Return type:access_path
Returns:The newly created access_path element.
Raises:OverflowError 
>>> access_path.offset_in_bits(102)
<cs.access_path [102]>
static star()

Get a new access path element corresponding to the star (*) operator.

Return type:access_path
Returns:The newly created access_path element. 
>>> access_path.star()
<cs.access_path *>
__repr__()

Get a representation of a access_path object that includes information useful for debugging.

Return type:str
Returns:The string representation. 
>>> v0 = access_path.addr()
>>> repr(v0)
'<cs.access_path &>'
__str__()

Get a simple string representation of a access_path object.

Return type:str
Returns:The string representation. 
>>> v0 = access_path.addr()
>>> str(v0)
'&'