Transform pointer arithmetic. More...

Inheritance diagram for RulePtrArith:

Public Member Functions
	RulePtrArith (const string &g)
	Constructor.

virtual Rule *	clone (const ActionGroupList &grouplist) const
	Clone the Rule. More...

virtual void	getOpList (vector< uint4 > &oplist) const
	List of op codes this rule operates on. More...

virtual int4	applyOp (PcodeOp *op, Funcdata &data)
	Attempt to apply this Rule. More...

Public Member Functions inherited from Rule
	Rule (const string &g, uint4 fl, const string &nm)
	Construct given group, properties name. More...

virtual	~Rule (void)
	Destructor.

const string &	getName (void) const
	Return the name of this Rule.

const string &	getGroup (void) const
	Return the group this Rule belongs to.

uint4	getNumTests (void)
	Get number of attempted applications.

uint4	getNumApply (void)
	Get number of successful applications.

void	setBreak (uint4 tp)
	Set a breakpoint on this Rule.

void	clearBreak (uint4 tp)
	Clear a breakpoint on this Rule.

void	turnOnWarnings (void)
	Enable warnings for this Rule.

void	turnOffWarnings (void)
	Disable warnings for this Rule.

bool	isDisabled (void) const
	Return true if this Rule is disabled.

void	setDisable (void)
	Disable this Rule (within its pool)

void	clearDisable (void)
	Enable this Rule (within its pool)

bool	checkActionBreak (void)
	Check if an action breakpoint is turned on. More...

uint4	getBreakPoint (void) const
	Return breakpoint toggles.

virtual void	reset (Funcdata &data)
	Reset this Rule. More...

virtual void	resetStats (void)
	Reset Rule statistics. More...

virtual void	printStatistics (ostream &s) const
	Print statistics for this Rule. More...

Static Private Member Functions
static bool	checkTerm (Varnode vn, AddTreeState state)
	Accumulate details of given term and continue tree traversal. More...

static bool	spanAddTree (PcodeOp op, AddTreeState state)
	Traverse the additive expression accumulating offset information. More...

static int4	transformPtr (PcodeOp bottom_op, PcodeOp ptr_op, int4 slot, Funcdata &data)
	Rewrite a pointer expression using PTRSUB and PTRADD. More...

Additional Inherited Members
Public Types inherited from Rule
enum	typeflags { type_disable = 1, rule_debug = 2, warnings_on = 4, warnings_given = 8 }
	Properties associated with a Rule. More...

Detailed Description

Transform pointer arithmetic.

Rule for converting integer arithmetic to pointer arithmetic. A string of INT_ADDs is converted into PTRADDs and PTRSUBs.

Basic algorithm: Starting with a varnode of known pointer type (with known size):

Generate list of terms added to pointer
Find all terms that are multiples of pointer size
Find all terms that are smaller than pointer size
Find sum of constants smaller than pointer size
Multiples get converted to PTRADD
Constant gets converted to nearest subfield offset
Everything else is just added back on

We need to be wary of most things being in the units of the space being pointed at. Type calculations are always in bytes so we need to convert between space units and bytes.

Member Function Documentation

◆ applyOp()

int4 RulePtrArith::applyOp	(	PcodeOp *	op,
		Funcdata &	data
	)

virtual

Attempt to apply this Rule.

This method contains the main logic for applying the Rule. It must use a given PcodeOp as the point at which the Rule applies. If it does apply, changes are made directly to the function and 1 (non-zero) is returned, otherwise 0 is returned.

Parameters

op	is the given PcodeOp where the Rule may apply
data	is the function to which to apply

Reimplemented from Rule.

References AddrSpace::addressToByteInt(), Varnode::beginDescend(), PcodeOp::code(), CPUI_INT_ADD, CPUI_LOAD, CPUI_PTRADD, CPUI_STORE, Varnode::endDescend(), PcodeOp::getIn(), Datatype::getMetatype(), PcodeOp::getOut(), TypePointer::getPtrTo(), Datatype::getSize(), Varnode::getType(), TypePointer::getWordSize(), Varnode::isConstant(), Varnode::isInput(), Varnode::isSpacebase(), Funcdata::isTypeRecoveryOn(), Funcdata::newConstant(), PcodeOp::numInput(), Funcdata::opSetAllInput(), Funcdata::opSetOpcode(), transformPtr(), and TYPE_PTR.

◆ checkTerm()

bool RulePtrArith::checkTerm	(	Varnode *	vn,
		AddTreeState *	state
	)

staticprivate

Accumulate details of given term and continue tree traversal.

If the given Varnode is a constant or multiplicative term, update totals in the state object. If the Varnode is additive, traverse its sub-terms.

Parameters

vn	is the given Varnode term
state	is the state object

Returns: true if Varnode is a NON-multiple

References PcodeOp::code(), AddTreeState::coeff, CPUI_COPY, CPUI_INT_ADD, CPUI_INT_MULT, Varnode::getDef(), PcodeOp::getIn(), Varnode::getOffset(), Varnode::isConstant(), Varnode::isWritten(), AddTreeState::multiple, AddTreeState::multsum, AddTreeState::nonmultsum, AddTreeState::ptr, AddTreeState::size, spanAddTree(), and AddTreeState::valid.

Referenced by spanAddTree().

◆ clone()

virtual Rule* RulePtrArith::clone ( const ActionGroupList & grouplist ) const

inlinevirtual

Clone the Rule.

If this Rule is a member of one of the groups in the grouplist, this returns a clone of the Rule, otherwise NULL is returned.

Parameters

grouplist is the list of groups being cloned

Returns: the cloned Rule or NULL

Implements Rule.

References ActionGroupList::contains(), Rule::getGroup(), and RulePtrArith().

◆ getOpList()

void RulePtrArith::getOpList ( vector< uint4 > & oplist ) const

virtual

List of op codes this rule operates on.

Populate the given array with all possible OpCodes this Rule might apply to. By default, this method returns all possible OpCodes

Parameters

oplist is the array to populate

Reimplemented from Rule.

References CPUI_INT_ADD.

◆ spanAddTree()

bool RulePtrArith::spanAddTree	(	PcodeOp *	op,
		AddTreeState *	state
	)

staticprivate

Traverse the additive expression accumulating offset information.

Parameters

op	is the root of the sub-expression to traverse
state	holds the offset information

Returns: true if the sub-expression is invalid or a NON-multiple

References checkTerm(), PcodeOp::getIn(), AddTreeState::nonmult, and AddTreeState::valid.

Referenced by checkTerm(), and transformPtr().

◆ transformPtr()

int4 RulePtrArith::transformPtr	(	PcodeOp *	bottom_op,
		PcodeOp *	ptr_op,
		int4	slot,
		Funcdata &	data
	)

staticprivate

Rewrite a pointer expression using PTRSUB and PTRADD.

Given a base pointer of known data-type and an additive expression involving the pointer, group the terms of the expression into:

Constant multiple of the base data-type
Non-constant multiples of the base data-type
Multiples of an array element size: rewrite using PTRADD
Drill down into sub-components of the base data-type: rewrite using PTRSUB
Remaining offsets

Parameters

bottom_op	is the root Varnode of the expression
ptr_op	is the PcodeOp taking the base pointer as input
slot	is the input slot of the base pointer
data	is the function being analyzed

Returns: 1 if modifications are made, 0 otherwise

References AddrSpace::addressToByte(), AddrSpace::byteToAddress(), AddrSpace::byteToAddressInt(), calc_mask(), AddTreeState::coeff, CPUI_INT_ADD, CPUI_INT_MULT, CPUI_PTRADD, CPUI_PTRSUB, PcodeOp::getAddr(), PcodeOp::getIn(), Datatype::getMetatype(), Varnode::getOffset(), PcodeOp::getOut(), TypePointer::getPtrTo(), Datatype::getSize(), Varnode::getSize(), Datatype::getSubType(), Varnode::getType(), TypePointer::getWordSize(), Varnode::isConstant(), AddTreeState::multiple, AddTreeState::multsum, Funcdata::newConstant(), Funcdata::newOpBefore(), AddTreeState::nonmult, AddTreeState::nonmultsum, Funcdata::opDestroy(), Funcdata::opSetOutput(), AddTreeState::ptr, sign_extend(), AddTreeState::size, spanAddTree(), TYPE_ARRAY, TYPE_SPACEBASE, TYPE_STRUCT, uintb_negate(), AddTreeState::valid, and Funcdata::warning().

Referenced by applyOp().

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

ruleaction.hh
ruleaction.cc

Public Member Functions

Static Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ applyOp()

◆ checkTerm()

◆ clone()

◆ getOpList()

◆ spanAddTree()

◆ transformPtr()