ValueSet Class Reference

A range of values attached to a Varnode within a data-flow subsystem. More...

#include <rangeutil.hh>

Classes
class	Equation
	An external that can be applied to a ValueSet. More...

Public Member Functions
const CircleRange *	getLandMark (void) const
	Get any landmark range. More...
void	printRaw (ostream &s) const
	Write a text description of to the given stream. More...

Static Public Attributes
static const int4	MAX_STEP = 32

Private Member Functions
bool	doesEquationApply (int4 num, int4 slot) const
	Does the indicated equation apply for the given input slot. More...
void	setVarnode (Varnode *v, int4 tCode)
	Attach this to given Varnode and set initial values. More...
void	addEquation (int4 slot, int4 type, const CircleRange &constraint)
	Insert an equation restricting this value set. More...
bool	computeTypeCode (void)
	Figure out if this value set is absolute or relative. More...
bool	iterate (Widener &widener)
	Regenerate this value set from operator inputs. More...

Private Attributes
int4	typeCode
	0=pure constant 1=stack relative
int4	numParams
	Number of input parameters to defining operation.
int4	count
	Depth first numbering / widening count.
OpCode	opCode
	Op-code defining Varnode.
bool	leftIsStable
	Set to true if left boundary of range didn't change (last iteration)
bool	rightIsStable
	Set to true if right boundary of range didn't change (last iteration)
Varnode *	vn
	Varnode whose set this represents.
CircleRange	range
	Range of values or offsets in this set.
vector< Equation >	equations
	Any equations associated with this value set.
Partition *	partHead
	If Varnode is a component head, pointer to corresponding Partition.
ValueSet *	next
	Next ValueSet to iterate.

Friends
class	ValueSetSolver

Detailed Description

A range of values attached to a Varnode within a data-flow subsystem.

This class acts as both the set of values for the Varnode and as a node in a sub-graph overlaying the full data-flow of the function containing the Varnode. The values are stored in the CircleRange field and can be interpreted either as absolute values (if typeCode is 0) or as values relative to a stack pointer or some other register (if typeCode is non-zero).

Member Function Documentation

addEquation()

void ValueSet::addEquation ( int4  slot, int4  type, const CircleRange &  constraint  )

private

Insert an equation restricting this value set.

Equations are stored as an array of (slot,range) pairs, ordered on slot.

Parameters

slot	is the given slot
type	is the constraint characteristic
constraint	is the given range

References equations.

computeTypeCode()

bool ValueSet::computeTypeCode ( void  )

private

Figure out if this value set is absolute or relative.

Examine the input value sets that determine this set and decide if it is relative. In general, this will be relative if any of its inputs are. Certain combinations are indeterminate, which this method flags by returning true. The Varnode attached to this must have a defining op.

Returns

true if there is an indeterminate combination

References CPUI_CAST, CPUI_COPY, CPUI_INDIRECT, CPUI_INT_ADD, CPUI_INT_SUB, CPUI_MULTIEQUAL, CPUI_PTRADD, CPUI_PTRSUB, numParams, opCode, typeCode, and vn.

Referenced by iterate().

doesEquationApply()

bool ValueSet::doesEquationApply ( int4  num, int4  slot  ) const

inlineprivate

Does the indicated equation apply for the given input slot.

Perform basic checks that the selected Equation exists and applies to the indicated input slot.

Parameters

num	is the index selecting an Equation
slot	is the indicated slot

Returns

true if the Equation exists and applies

References equations, and typeCode.

Referenced by iterate().

getLandMark()

const CircleRange * ValueSet::getLandMark

(

void

)

const

Get any landmark range.

If a landmark was associated with this value set, return its range, otherwise return null.

Returns

the landmark range or null

References equations, and typeCode.

Referenced by WidenerFull::doWidening().

iterate()

bool ValueSet::iterate ( Widener &  widener )

private

Regenerate this value set from operator inputs.

Recalculate this value set by grabbing the value sets of the inputs to the operator defining the Varnode attached to this value set and pushing them forward through the operator.

Returns

true if there was a change to this value set

References Widener::checkFreeze(), CircleRange::circleUnion(), computeTypeCode(), count, CPUI_MULTIEQUAL, doesEquationApply(), Widener::doWidening(), equations, CircleRange::intersect(), leftIsStable, MAX_STEP, CircleRange::minimalContainer(), numParams, opCode, partHead, CircleRange::pushForwardBinary(), CircleRange::pushForwardTrinary(), CircleRange::pushForwardUnary(), range, rightIsStable, and vn.

Referenced by ValueSetSolver::solve().

printRaw()

void ValueSet::printRaw

(

ostream &

s

)

const

Write a text description of to the given stream.

Parameters

s	is the stream to print to

References CPUI_MAX, get_opname(), opCode, CircleRange::printRaw(), Varnode::printRaw(), range, typeCode, and vn.

setVarnode()

void ValueSet::setVarnode ( Varnode *  v, int4  tCode  )

private

Attach this to given Varnode and set initial values.

The initial values in this are set based on the type of Varnode:

• Constant gets the single value
• Input gets all possible values
• Other Varnodes that are written start with an empty set

Parameters

v	is the given Varnode to attach to
tCode	indicates whether to treat values as constants are relative offsets

References CPUI_COPY, CPUI_INDIRECT, CPUI_MAX, leftIsStable, numParams, opCode, range, rightIsStable, CircleRange::setFull(), CircleRange::setRange(), typeCode, and vn.

Member Data Documentation

MAX_STEP

const int4 ValueSet::MAX_STEP = 32

static

Maximum step inferred for a value set

Referenced by iterate().

---

The documentation for this class was generated from the following files:

• rangeutil.hh
• rangeutil.cc