Transform pointer arithmetic. More...

Inheritance diagram for ghidra::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 ghidra::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	clearBreakPoints (void)
	Clear all breakpoints 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 Public Member Functions
static int4	evaluatePointerExpression (PcodeOp *op, int4 slot)
	Determine if the expression rooted at the given INT_ADD operation is ready for conversion. More...

Static Private Member Functions
static bool	verifyPreferredPointer (PcodeOp *op, int4 slot)
	Test for other pointers in the ADD tree above the given op that might be a preferred base. More...

Additional Inherited Members
Public Types inherited from ghidra::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 ghidra::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 ghidra::Rule.

References ghidra::AddTreeState::apply(), ghidra::AddTreeState::ct, ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::Varnode::getTypeReadFacing(), ghidra::Funcdata::hasTypeRecoveryStarted(), ghidra::AddTreeState::initAlternateForm(), ghidra::PcodeOp::numInput(), and ghidra::TYPE_PTR.

◆ clone()

virtual Rule* ghidra::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 ghidra::Rule.

References ghidra::ActionGroupList::contains(), and ghidra::AddTreeState::data.

◆ evaluatePointerExpression()

int4 ghidra::RulePtrArith::evaluatePointerExpression	(	PcodeOp *	op,
		int4	slot
	)

static

Determine if the expression rooted at the given INT_ADD operation is ready for conversion.

Converting an expression of INT_ADDs into PTRSUBs and PTRADDs requires that the base pointer be at the root of the expression tree. This method evaluates whether given root has the base pointer at the bottom. If not, a push transform needs to be performed before RulePtrArith can apply. This method returns a command code:

0 if no action should be taken, the expression is not fully linked or should not be converted
1 if a push action should be taken, prior to conversion
2 if the pointer arithmetic conversion can proceed
Parameters

op is the given INT_ADD

slot is the index of the pointer

Returns
the command code

References ghidra::Varnode::beginDescend(), ghidra::PcodeOp::code(), ghidra::CPUI_INT_ADD, ghidra::CPUI_LOAD, ghidra::CPUI_STORE, ghidra::Varnode::endDescend(), ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::PcodeOp::getOut(), ghidra::PcodeOp::getSlot(), ghidra::Varnode::getTypeReadFacing(), ghidra::Varnode::isConstant(), ghidra::Varnode::isFree(), ghidra::Varnode::isInput(), ghidra::Varnode::isSpacebase(), and ghidra::TYPE_PTR.

Referenced by ghidra::RulePushPtr::applyOp().

◆ getOpList()

void ghidra::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 ghidra::Rule.

References ghidra::CPUI_INT_ADD.

◆ verifyPreferredPointer()

bool ghidra::RulePtrArith::verifyPreferredPointer	(	PcodeOp *	op,
		int4	slot
	)

staticprivate

Test for other pointers in the ADD tree above the given op that might be a preferred base.

This tests the condition of RulePushPtr on the node immediately above the given putative base pointer

Parameters

op	is the given op
slot	is the input slot of the putative base pointer

Returns: true if the indicated slot holds the preferred pointer

References ghidra::PcodeOp::code(), ghidra::CPUI_INT_ADD, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::Varnode::getTypeReadFacing(), ghidra::Varnode::isWritten(), and ghidra::TYPE_PTR.

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

ruleaction.hh
ruleaction.cc

Public Member Functions

Static Public Member Functions

Static Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ applyOp()

◆ clone()

◆ evaluatePointerExpression()

◆ getOpList()

◆ verifyPreferredPointer()