decompiler  1.0.0
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ghidra::RuleThreeWayCompare Class Reference

Simplify expressions involving three-way comparisons. More...

Inheritance diagram for ghidra::RuleThreeWayCompare:
ghidra::Rule

Public Member Functions

 RuleThreeWayCompare (const string &g)
 Constructor.
 
virtual Ruleclone (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 ghidra::Rule
 Rule (const string &g, uint4 fl, const string &nm)
 Construct given group, properties name. More...
 
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. More...
 
uint4 getBreakPoint (void) const
 Return breakpoint toggles.
 
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 Public Member Functions

static PcodeOpdetectThreeWay (PcodeOp *op, bool &isPartial)
 Detect a three-way calculation. More...
 
static int4 testCompareEquivalence (PcodeOp *lessop, PcodeOp *lessequalop)
 Make sure comparisons match properly for a three-way. More...
 

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

Simplify expressions involving three-way comparisons.

A three-way comparison is the expression

This gives the result (-1, 0, or 1) depending on whether V is less-than, equal, or greater-than W. This Rule looks for secondary comparisons of the three-way, such as

Member Function Documentation

◆ applyOp()

int4 ghidra::RuleThreeWayCompare::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
opis the given PcodeOp where the Rule may apply
datais the function to which to apply

Reimplemented from ghidra::Rule.

References ghidra::calc_mask(), ghidra::PcodeOp::code(), ghidra::CPUI_FLOAT_EQUAL, ghidra::CPUI_FLOAT_LESS, ghidra::CPUI_FLOAT_NOTEQUAL, ghidra::CPUI_INT_ADD, ghidra::CPUI_INT_EQUAL, ghidra::CPUI_INT_NOTEQUAL, ghidra::CPUI_INT_SLESSEQUAL, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::Varnode::getOffset(), ghidra::Varnode::getSize(), ghidra::Varnode::isConstant(), ghidra::Varnode::isFree(), ghidra::Varnode::isWritten(), ghidra::Funcdata::newConstant(), ghidra::Funcdata::opSetInput(), and ghidra::Funcdata::opSetOpcode().

◆ clone()

virtual Rule* ghidra::RuleThreeWayCompare::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
grouplistis the list of groups being cloned
Returns
the cloned Rule or NULL

Implements ghidra::Rule.

References ghidra::ActionGroupList::contains(), and ghidra::AddTreeState::data.

◆ detectThreeWay()

PcodeOp * ghidra::RuleThreeWayCompare::detectThreeWay ( PcodeOp op,
bool &  isPartial 
)
static

Detect a three-way calculation.

A three-way expression looks like:

  • zext( V < W ) + zext( V <= W ) - 1 in some permutation

The comparisons can signed, unsigned, or floating-point.

Parameters
opis the putative root INT_ADD of the calculation
isPartialis set to true if a partial form is detected
Returns
the less-than op or NULL if no three-way was detected

References ghidra::calc_mask(), ghidra::PcodeOp::code(), ghidra::CPUI_FLOAT_LESS, ghidra::CPUI_INT_ADD, ghidra::CPUI_INT_LESS, ghidra::CPUI_INT_SLESS, ghidra::CPUI_INT_ZEXT, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::Varnode::getOffset(), ghidra::Varnode::getSize(), ghidra::Varnode::isConstant(), and ghidra::Varnode::isWritten().

◆ getOpList()

void ghidra::RuleThreeWayCompare::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
oplistis the array to populate

Reimplemented from ghidra::Rule.

References ghidra::CPUI_INT_EQUAL, ghidra::CPUI_INT_NOTEQUAL, ghidra::CPUI_INT_SLESS, and ghidra::CPUI_INT_SLESSEQUAL.

◆ testCompareEquivalence()

int4 ghidra::RuleThreeWayCompare::testCompareEquivalence ( PcodeOp lessop,
PcodeOp lessequalop 
)
static

Make sure comparisons match properly for a three-way.

Given zext(V < W) + zext(X <= Y), make sure comparisons match, i.e V matches X and W matches Y. Take into account that the LESSEQUAL may have been converted to a LESS. Return:

  • 0 if configuration is correct
  • 1 if correct but roles of lessop and lessequalop must be swapped
  • -1 if not the correct configuration
    Parameters
    lessopis the putative LESS PcodeOp
    lessequalopis the putative LESSEQUAL PcodeOp
    Returns
    0, 1, or -1

References ghidra::PcodeOp::code(), ghidra::CPUI_FLOAT_LESS, ghidra::CPUI_FLOAT_LESSEQUAL, ghidra::CPUI_INT_LESS, ghidra::CPUI_INT_LESSEQUAL, ghidra::CPUI_INT_SLESS, ghidra::CPUI_INT_SLESSEQUAL, ghidra::PcodeOp::getIn(), ghidra::Varnode::getOffset(), and ghidra::Varnode::isConstant().


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