A helper class for describing the similarity of the boolean condition between 2 CBRANCH operations. More...

#include <condexe.hh>

Public Member Functions
	ConditionMarker (void)
	Constructor.

	~ConditionMarker (void)
	Destructor. More...

bool	verifyCondition (PcodeOp op, PcodeOp initop)
	Perform the correlation test on two CBRANCH operations.

int4	getMultiSlot (void) const
	Get the MULTIEQUAL slot in the critical path.

bool	getFlip (void) const
	Return true is the expressions are anti-correlated.

Static Public Member Functions
static bool	varnodeSame (Varnode a, Varnode b)
	Do the given Varnodes hold the same value, possibly as constants. More...

static bool	varnodeComplement (Varnode a, Varnode b)
	Do the given boolean Varnodes always hold complementary values. More...

Private Member Functions
void	setupInitOp (PcodeOp *op)
	Map out the root boolean expression. More...

Varnode *	findMatch (PcodeOp *op)
	Find a matching Varnode in the root expression producing the given CBRANCH boolean. More...

bool	sameOpComplement (PcodeOp bin1op, PcodeOp bin2op)
	Test if two operations with same opcode produce complementary boolean values. More...

bool	andOrComplement (PcodeOp bin1op, PcodeOp bin2op)
	Check if given p-code ops are complements where one is an BOOL_AND and the other is an BOOL_OR. More...

bool	finalJudgement (Varnode *vn)
	Determine if the two boolean expressions always produce the same or complementary values. More...

Private Attributes
PcodeOp *	initop
	The root CBRANCH operation to compare against.

Varnode *	basevn
	The boolean Varnode on which the root CBRANCH keys.

Varnode *	boolvn
	If basevn is defined by BOOL_NEGATE, this is the unnegated Varnode.

Varnode *	bool2vn
	If the first param to binaryop is defined by BOOL_NEGATE, this is the unnegated Varnode.

Varnode *	bool3vn
	If the second param to binaryop is defined by BOOL_NEGATE, this is the unnegated Varnode.

PcodeOp *	binaryop
	The binary operator producing the root boolean (if non-null)

bool	matchflip
	True if the compared CBRANCH keys on the opposite boolean value of the root.

int4	state
	Depth of critical path.

PcodeOp *	opstate [2]
	p-code operations along the critical path

bool	flipstate [2]
	Boolean negation along the critical path.

int4	slotstate [2]
	Input Varnode to follow to stay on critical path.

bool	multion
	True if MULTIEQUAL used in condition.

bool	binon
	True if a binary operator is used in condition.

int4	multislot
	Input slot of MULTIEQUAL on critical path, -1 if no MULTIEQUAL.

Detailed Description

A helper class for describing the similarity of the boolean condition between 2 CBRANCH operations.

This class determines if two CBRANCHs share the same condition. It also determines if the conditions are complements of each other, and/or they are shared along only one path.

The expression computing the root boolean value for one CBRANCH is marked out by setupInitOp(). For the other CBRANCH, findMatch() tries to find common Varnode in its boolean expression and then maps a critical path from the Varnode to the final boolean. Assuming the common Varnode exists, the method finalJudgement() decides if the two boolean values are the same, uncorrelated, or complements of one another.

Constructor & Destructor Documentation

◆ ~ConditionMarker()

ConditionMarker::~ConditionMarker ( void )

Destructor.

Any marks on Varnodes in the root expression are cleared.

References basevn, binaryop, bool2vn, bool3vn, boolvn, Varnode::clearMark(), and PcodeOp::getIn().

Member Function Documentation

◆ andOrComplement()

bool ConditionMarker::andOrComplement	(	PcodeOp *	bin1op,
		PcodeOp *	bin2op
	)

private

Check if given p-code ops are complements where one is an BOOL_AND and the other is an BOOL_OR.

Parameters

bin1op	is the first PcodeOp
bin2op	is the second

Returns: true if the p-code ops produce complementary values

References PcodeOp::code(), CPUI_BOOL_AND, CPUI_BOOL_OR, PcodeOp::getIn(), and varnodeComplement().

Referenced by finalJudgement().

◆ finalJudgement()

bool ConditionMarker::finalJudgement ( Varnode * vn )

private

Determine if the two boolean expressions always produce the same or complementary values.

A common Varnode in the two expressions is given. If the boolean expressions are uncorrelated, false is returned, otherwise true is returned. If the expressions are correlated but always hold opposite values, the field matchflip is set to true.

Parameters

vn	is the common Varnode

Returns: true if the expressions are correlated

References andOrComplement(), basevn, binaryop, binon, boolvn, PcodeOp::code(), get_booleanflip(), PcodeOp::getIn(), initop, PcodeOp::isBooleanFlip(), PcodeOp::isBoolOutput(), matchflip, opstate, sameOpComplement(), state, and varnodeSame().

Referenced by verifyCondition().

◆ findMatch()

Varnode * ConditionMarker::findMatch ( PcodeOp * op )

private

Find a matching Varnode in the root expression producing the given CBRANCH boolean.

Walk the tree rooted at the given p-code op, looking for things marked in the tree rooted at initop. Trim everything but BOOL_NEGATE operations, one MULTIEQUAL, and one binary boolean operation. If there is a Varnode in common with the root expression, this is returned, and the tree traversal state holds the path from the boolean value to the common Varnode.

Parameters

op	is the given CBRANCH op to compare

Returns: the Varnode in common with the root expression or NULL

References PcodeOp::binary, binon, PcodeOp::code(), CPUI_BOOL_NEGATE, CPUI_MULTIEQUAL, flipstate, Varnode::getDef(), PcodeOp::getEvalType(), PcodeOp::getIn(), PcodeOp::isBooleanFlip(), PcodeOp::isBoolOutput(), Varnode::isMark(), Varnode::isWritten(), matchflip, multion, PcodeOp::numInput(), opstate, slotstate, and state.

Referenced by verifyCondition().

◆ sameOpComplement()

bool ConditionMarker::sameOpComplement	(	PcodeOp *	bin1op,
		PcodeOp *	bin2op
	)

private

Test if two operations with same opcode produce complementary boolean values.

This only tests for cases where the opcode is INT_LESS or INT_SLESS and one of the inputs is constant.

Parameters

bin1op	is the first p-code op to compare
bin2op	is the second p-code op to compare

Returns: true if the two operations always produce complementary values

References PcodeOp::code(), CPUI_INT_LESS, CPUI_INT_SLESS, PcodeOp::getIn(), Varnode::getOffset(), Varnode::getSize(), Varnode::isConstant(), signbit_negative(), and varnodeSame().

Referenced by finalJudgement().

◆ setupInitOp()

void ConditionMarker::setupInitOp ( PcodeOp * op )

private

Map out the root boolean expression.

Starting with the CBRANCH, the key Varnodes in the expression producing the boolean value are marked. BOOL_NEGATE operations are traversed, but otherwise only one level of operator is walked.

Parameters