RuleSLess2Zero Class Reference

Simplify INT_SLESS applied to 0 or -1. More...

Inheritance diagram for RuleSLess2Zero:

Public Member Functions
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...
bool	checkActionBreak (void)
	Check if an action breakpoint is turned on. More...
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 Varnode *	getHiBit (PcodeOp *op)
	Get the piece containing the sign-bit. 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

Simplify INT_SLESS applied to 0 or -1.

Forms include:

• 0 s< V * -1 => V s< 0
• V * -1 s< 0 => 0 s< V
• -1 s< SUB(V,#hi) => -1 s< V
• SUB(V,#hi) s< 0 => V s< 0
• -1 s< ~V => V s< 0
• ~V s< 0 => -1 s< V
• (V & 0xf000) s< 0 => V s< 0
• -1 s< (V & 0xf000) => -1 s< V -CONCAT(V,W) s< 0 => V s< 0 --1 s< CONCAT(V,W) => -1 s> V`

There is a second set of forms where one side of the comparison is built out of a high and low piece, where the high piece determines the sign bit:

• -1 s< (hi + lo) => -1 s< hi
• (hi + lo) s< 0 => hi s< 0

Member Function Documentation

applyOp()

int4 RuleSLess2Zero::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 calc_mask(), CPUI_INT_AND, CPUI_INT_EQUAL, CPUI_INT_MULT, CPUI_INT_NEGATE, CPUI_INT_NOTEQUAL, CPUI_PIECE, CPUI_SUBPIECE, getHiBit(), Varnode::loneDescend(), Funcdata::newConstant(), Funcdata::opSetInput(), and Funcdata::opSetOpcode().

clone()

virtual Rule* RuleSLess2Zero::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().

getHiBit()

Varnode * RuleSLess2Zero::getHiBit ( PcodeOp *  op )

staticprivate

Get the piece containing the sign-bit.

If the given PcodeOp pieces together 2 Varnodes only one of which is determining the high bit, return that Varnode.

Parameters

op	is the given PcodeOp

Returns

the Varnode holding the high bit

References calc_mask(), CPUI_INT_ADD, CPUI_INT_OR, and CPUI_INT_XOR.

Referenced by applyOp().

getOpList()

void RuleSLess2Zero::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_SLESS.

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

• ruleaction.hh
• ruleaction.cc