ghidra::AddExpression Class Reference

Class for lightweight matching of two additive expressions. More...

#include <expression.hh>

Classes
class	Term
	A term in the expression. More...

Public Member Functions
	AddExpression (void)
	Construct an empty expression.
void	gatherTwoTermsSubtract (Varnode *a, Varnode *b)
	Walk expression given two roots being subtracted from one another.
void	gatherTwoTermsAdd (Varnode *a, Varnode *b)
	Walk expression given two roots being added to each other.
void	gatherTwoTermsRoot (Varnode *root)
	Gather up to 2 terms given root Varnode.
bool	isEquivalent (const AddExpression &op2) const
	Determine if 2 expressions are equivalent.

Private Member Functions
void	add (Varnode *vn, uintb coeff)
	Add a term to the expression.
void	gather (Varnode *vn, uintb coeff, int4 depth)
	Gather terms in the expression from a root point.

Private Attributes
uintb	constval
	Collected constants in the expression.
int4	numTerms
	Number of terms.
Term	terms [2]
	Terms making up the expression.

Detailed Description

Class for lightweight matching of two additive expressions.

Collect (up to 2) terms along with any constants and coefficients.

Member Function Documentation

gather()

void ghidra::AddExpression::gather ( Varnode *  vn, uintb  coeff, int4  depth  )

private

Gather terms in the expression from a root point.

Recursively collect terms, up to the given depth. INT_ADD either contributes to the constant sum, or it is recursively walked. Term coefficients are collected from INT_MULT with a constant.

Parameters

vn	is the root of the (sub)expression
coeff	is the current multiplicative coefficient of the subexpression
depth	is the current depth

References add(), ghidra::calc_mask(), ghidra::PcodeOp::code(), constval, ghidra::CPUI_INT_ADD, ghidra::CPUI_INT_MULT, gather(), ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::Varnode::getOffset(), ghidra::Varnode::getSize(), ghidra::Varnode::isConstant(), and ghidra::Varnode::isWritten().

Referenced by gather(), gatherTwoTermsAdd(), gatherTwoTermsRoot(), and gatherTwoTermsSubtract().

gatherTwoTermsAdd()

void ghidra::AddExpression::gatherTwoTermsAdd	(	Varnode *	a,
		Varnode *	b
	)

Walk expression given two roots being added to each other.

Gather up to two non-constant additive terms, given two root Varnodes being added

Parameters

a	is the first root
b	is the second root being added to the first

References gather(), and ghidra::Varnode::isConstant().

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

gatherTwoTermsRoot()

void ghidra::AddExpression::gatherTwoTermsRoot

(

Varnode *

root

)

Gather up to 2 terms given root Varnode.

Gather up to two non-constant additive terms in the expression at the given root.

Parameters

root	is the root Varnode

References gather().

Referenced by ghidra::RuleSborrow::applyOp(), and ghidra::RuleScarry::applyOp().

gatherTwoTermsSubtract()

void ghidra::AddExpression::gatherTwoTermsSubtract	(	Varnode *	a,
		Varnode *	b
	)

Walk expression given two roots being subtracted from one another.

Gather up to two non-constant additive terms, given two root Varnodes that are being subtracted.

Parameters

a	is the first root
b	is the second root being subtracted from the first

References ghidra::calc_mask(), gather(), ghidra::Varnode::getSize(), and ghidra::Varnode::isConstant().

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

isEquivalent()

bool ghidra::AddExpression::isEquivalent

(

const AddExpression &

op2

)

const

Determine if 2 expressions are equivalent.

The value true is returned if it can be proven that the expressions always produce the same value.

Parameters

op2	is the other expression to compare with this

Returns

true if the expressions are equivalent

References constval, isEquivalent(), ghidra::AddExpression::Term::isEquivalent(), numTerms, and terms.

Referenced by ghidra::RuleSborrow::applyOp(), ghidra::RuleScarry::applyOp(), and isEquivalent().

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

• expression.hh
• expression.cc