A helper class to mark up predicated INT_OR expressions. More...

Public Member Functions
bool	discoverZeroSlot (Varnode *vn)
	Check if vn is produced by a 2-branch MULTIEQUAL, one side of which is a zero constant. More...

bool	discoverCbranch (void)
	Find CBRANCH operation that determines whether zero is set or not. More...

void	discoverPathIsTrue (void)
	Does the condBlock true outgoing edge flow to the block that sets zero. More...

bool	discoverConditionalZero (Varnode *vn)
	Verify that CBRANCH boolean expression is either (vn == 0) or (vn != 0) More...

Public Attributes
PcodeOp *	op
	Base MULTIEQUAL op.

int4	zeroSlot
	Input slot containing path that sets zero.

const FlowBlock *	zeroBlock
	Final block in path that sets zero.

const FlowBlock *	condBlock
	Conditional block determining if zero is set or not.

PcodeOp *	cbranch
	CBRANCH determining if zero is set.

Varnode *	otherVn
	Other (non-zero) Varnode getting set on other path.

bool	zeroPathIsTrue
	True if path to zero set is the true path out of condBlock.

Detailed Description

A helper class to mark up predicated INT_OR expressions.

Member Function Documentation

◆ discoverCbranch()

bool ghidra::RuleOrPredicate::MultiPredicate::discoverCbranch ( void )

Find CBRANCH operation that determines whether zero is set or not.

Assuming that op is a 2-branch MULTIEQUAL as per discoverZeroSlot(), try to find a single CBRANCH whose two out edges correspond to the in edges of the MULTIEQUAL. In this case, the boolean expression controlling the CBRANCH is also controlling whether zero flows into the MULTIEQUAL output Varnode.

Returns: true if a single controlling CBRANCH is found

References ghidra::CPUI_CBRANCH, ghidra::FlowBlock::getIn(), ghidra::FlowBlock::getParent(), ghidra::FlowBlock::lastOp(), ghidra::FlowBlock::sizeIn(), and ghidra::FlowBlock::sizeOut().

Referenced by ghidra::RuleOrPredicate::applyOp(), and ghidra::RuleOrPredicate::checkSingle().

◆ discoverConditionalZero()

bool ghidra::RuleOrPredicate::MultiPredicate::discoverConditionalZero ( Varnode * vn )

Verify that CBRANCH boolean expression is either (vn == 0) or (vn != 0)

Modify zeroPathIsTrue so that if it is true, then: A vn value equal to zero, causes execution to flow to where the output of MULTIEQUAL is set to zero.

Parameters