Remove certain NaN operations by assuming their result is always false. More...

Inheritance diagram for ghidra::RuleIgnoreNan:

Collaboration diagram for ghidra::RuleIgnoreNan:

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

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

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

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

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

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.

uint4	getBreakPoint (void) const
	Return breakpoint toggles.

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

virtual void	resetStats (void)
	Reset Rule statistics.

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

Static Private Member Functions
static bool	checkBackForCompare (Varnode floatVar, Varnode root)
	Check if a boolean Varnode incorporates a floating-point comparison with the given value.

static bool	isAnotherNan (Varnode *vn)
	Test if the given Varnode is produced by a NaN operation.

static Varnode *	testForComparison (Varnode floatVar, PcodeOp op, int4 slot, OpCode matchCode, int4 &count, Funcdata &data)
	Test if a boolean expression incorporates a floating-point comparison, and remove the NaN data-flow if it does.

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

Remove certain NaN operations by assuming their result is always false.

This rule can be configured to remove either all FLOAT_NAN operations or only those that protect floating-point comparisons.

Member Function Documentation

◆ applyOp()

int4 ghidra::RuleIgnoreNan::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::Varnode::beginDescend(), ghidra::PcodeOp::code(), ghidra::CPUI_BOOL_AND, ghidra::CPUI_BOOL_NEGATE, ghidra::CPUI_BOOL_OR, ghidra::CPUI_COPY, ghidra::Varnode::endDescend(), ghidra::Funcdata::getArch(), ghidra::PcodeOp::getIn(), ghidra::PcodeOp::getOut(), ghidra::PcodeOp::getSlot(), ghidra::Varnode::isFree(), ghidra::Architecture::nan_ignore_all, ghidra::Funcdata::newConstant(), ghidra::Funcdata::opSetInput(), ghidra::Funcdata::opSetOpcode(), and testForComparison().

◆ checkBackForCompare()

bool ghidra::RuleIgnoreNan::checkBackForCompare	(	Varnode *	floatVar,
		Varnode *	root
	)

staticprivate

Check if a boolean Varnode incorporates a floating-point comparison with the given value.

The Varnode can either be the direct output of a comparison, or it can be a BOOL_OR or BOOL_AND, combining output from the comparison.

Parameters

floatVar	is the given value the comparison must take as input
root	is the boolean Varnode

Returns: true if the boolean Varnode incorporates the comparison

References ghidra::PcodeOp::code(), ghidra::CPUI_BOOL_AND, ghidra::CPUI_BOOL_NEGATE, ghidra::CPUI_BOOL_OR, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::PcodeOp::getOpcode(), ghidra::PcodeOp::isBoolOutput(), ghidra::TypeOp::isFloatingPointOp(), ghidra::Varnode::isWritten(), and ghidra::PcodeOp::numInput().

Referenced by testForComparison().

◆ clone()

virtual Rule * ghidra::RuleIgnoreNan::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::Rule::getGroup().

◆ getOpList()

void ghidra::RuleIgnoreNan::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_FLOAT_NAN.

◆ isAnotherNan()

bool ghidra::RuleIgnoreNan::isAnotherNan ( Varnode * vn )

staticprivate

Test if the given Varnode is produced by a NaN operation.

The Varnode can be the direct or negated output of a NaN.

Parameters

vn	is the given Varnode

Returns: true if the Varnode is the output of the NaN

References ghidra::PcodeOp::code(), ghidra::CPUI_BOOL_NEGATE, ghidra::CPUI_FLOAT_NAN, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), and ghidra::Varnode::isWritten().

Referenced by testForComparison().

◆ testForComparison()

Varnode * ghidra::RuleIgnoreNan::testForComparison	(	Varnode *	floatVar,
		PcodeOp *	op,
		int4	slot,
		OpCode	matchCode,
		int4 &	count,
		Funcdata &	data
	)

staticprivate

Test if a boolean expression incorporates a floating-point comparison, and remove the NaN data-flow if it does.

The given PcodeOp takes input from a NaN operation through a specific slot. We look for a floating-point comparison PcodeOp (FLOAT_LESS, FLOAT_LESSEQUAL, FLOAT_EQUAL, or FLOAT_NOTEQUAL) that is combined with the given PcodeOp and has the same input Varnode as the NaN. The data-flow must be combined either through a BOOL_OR, BOOL_AND, INT_EQUAL, or INT_NOTEQUAL operation, or the given PcodeOp must be a CBRANCH that protects immediate control-flow to another CBRANCH taking the result of the comparison as input. If a matching comparison is found, the NaN input to the given PcodeOp is removed, assuming the output of the NaN operation is always false. If a NaN result is combined through a BOOL_OR, it must be unmodified, but a NaN result combined through a BOOL_AND must be negated.

Parameters

floatVar	is the input Varnode to NaN operation
op	is the given PcodeOp to test
slot	is the input index of the NaN operation
matchCode	is BOOL_AND if the NaN result has been negated, BOOL_OR if not
count	is incremented if a comparison is found and the NaN input is removed
data	is the function

Returns: the output of the given PcodeOp if it has an opcode matching matchCode

References checkBackForCompare(), ghidra::PcodeOp::code(), ghidra::CPUI_BOOL_OR, ghidra::CPUI_CBRANCH, ghidra::CPUI_COPY, ghidra::CPUI_INT_EQUAL, ghidra::CPUI_INT_NOTEQUAL, ghidra::PcodeOp::getIn(), ghidra::FlowBlock::getOut(), ghidra::PcodeOp::getOut(), ghidra::PcodeOp::getParent(), isAnotherNan(), ghidra::PcodeOp::isBooleanFlip(), ghidra::FlowBlock::lastOp(), ghidra::Funcdata::newConstant(), ghidra::Funcdata::opRemoveInput(), ghidra::Funcdata::opSetInput(), and ghidra::Funcdata::opSetOpcode().

Referenced by applyOp().

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

/builds/appsec/reveng-binrw/ghidraplusplus/src/dec/ruleaction.hh
/builds/appsec/reveng-binrw/ghidraplusplus/src/dec/ruleaction.cc

Public Member Functions

Static Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ applyOp()

◆ checkBackForCompare()

◆ clone()

◆ getOpList()

◆ isAnotherNan()

◆ testForComparison()