Fill-in CPUI_CAST p-code ops as required by the casting strategy. More...

#include <coreaction.hh>

Inheritance diagram for ghidra::ActionSetCasts:

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

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

virtual int4	apply (Funcdata &data)
	Make a single attempt to apply this Action. More...

Public Member Functions inherited from ghidra::Action
	Action (uint4 f, const string &nm, const string &g)
	Base constructor for an Action. More...

virtual	~Action (void)
	Destructor.

virtual void	printStatistics (ostream &s) const
	Dump statistics to stream. More...

int4	perform (Funcdata &data)
	Perform this action (if necessary) More...

bool	setBreakPoint (uint4 tp, const string &specify)
	Set a breakpoint on this action. More...

virtual void	clearBreakPoints (void)
	Clear all breakpoints set on this Action.

bool	setWarning (bool val, const string &specify)
	Set a warning on this action. More...

bool	disableRule (const string &specify)
	Disable a specific Rule within this. More...

bool	enableRule (const string &specify)
	Enable a specific Rule within this. More...

const string &	getName (void) const
	Get the Action's name.

const string &	getGroup (void) const
	Get the Action's group.

uint4	getStatus (void) const
	Get the current status of this Action.

uint4	getNumTests (void)
	Get the number of times apply() was invoked.

uint4	getNumApply (void)

virtual void	reset (Funcdata &data)
	Reset the Action for a new function. More...

virtual void	resetStats (void)
	Reset all the counts to zero. More...

virtual int4	print (ostream &s, int4 num, int4 depth) const
	Print a description of this Action to stream. More...

virtual void	printState (ostream &s) const
	Print status to stream. More...

virtual Action *	getSubAction (const string &specify)
	Retrieve a specific sub-action by name. More...

virtual Rule *	getSubRule (const string &specify)
	Retrieve a specific sub-rule by name. More...

Static Private Member Functions
static void	checkPointerIssues (PcodeOp op, Varnode vn, Funcdata &data)
	Check if the data-type of the given value being used as a pointer makes sense. More...

static bool	testStructOffset0 (Varnode vn, PcodeOp op, Datatype ct, CastStrategy castStrategy)
	Test if the given cast conflict can be resolved by passing to the first structure field. More...

static bool	tryResolutionAdjustment (PcodeOp *op, int4 slot, Funcdata &data)
	Try to adjust the input and output Varnodes to eliminate a CAST. More...

static bool	isOpIdentical (Datatype ct1, Datatype ct2)
	Test if two data-types are operation identical. More...

static int4	resolveUnion (PcodeOp *op, int4 slot, Funcdata &data)
	If the given op reads a pointer to a union, insert the CPUI_PTRSUB that resolves the union. More...

static int4	castOutput (PcodeOp op, Funcdata &data, CastStrategy castStrategy)
	Insert cast to output Varnode type after given PcodeOp if it is necessary. More...

static int4	castInput (PcodeOp op, int4 slot, Funcdata &data, CastStrategy castStrategy)
	Insert cast to produce the input Varnode to a given PcodeOp if necessary. More...

static PcodeOp *	insertPtrsubZero (PcodeOp op, int4 slot, Datatype ct, Funcdata &data)
	Insert a PTRSUB with offset 0 that accesses a field of the given data-type. More...

Additional Inherited Members
Public Types inherited from ghidra::Action
enum	ruleflags { rule_repeatapply = 4, rule_onceperfunc = 8, rule_oneactperfunc = 16, rule_debug = 32, rule_warnings_on = 64, rule_warnings_given = 128 }
	Boolean behavior properties governing this particular Action. More...

enum	statusflags { status_start =1, status_breakstarthit =2, status_repeat =4, status_mid =8, status_end =16, status_actionbreak =32 }
	Boolean properties describing the status of an action. More...

enum	breakflags { break_start = 1, tmpbreak_start = 2, break_action = 4, tmpbreak_action = 8 }
	Break points associated with an Action. More...

Protected Member Functions inherited from ghidra::Action
void	issueWarning (Architecture *glb)
	Warn that this Action has applied. More...

bool	checkStartBreak (void)
	Check start breakpoint. More...

bool	checkActionBreak (void)
	Check action breakpoint. More...

void	turnOnWarnings (void)
	Enable warnings for this Action.

void	turnOffWarnings (void)
	Disable warnings for this Action.

Protected Attributes inherited from ghidra::Action
int4	lcount
	Changes not including last call to apply()

int4	count
	Number of changes made by this action so far.

uint4	status
	Current status.

uint4	breakpoint
	Breakpoint properties.

uint4	flags
	Behavior properties.

uint4	count_tests
	Number of times apply() has been called.

uint4	count_apply
	Number of times apply() made changes.

string	name
	Name of the action.

string	basegroup
	Base group this action belongs to.

Detailed Description

Fill-in CPUI_CAST p-code ops as required by the casting strategy.

Setting the casts is complicated by type inference and implied variables. By the time this Action is run, the type inference algorithm has labeled every Varnode with what it thinks the type should be. This casting algorithm tries to get the code to legally match this inference result by adding casts. Following the data flow, it tries the best it can to get each token to match the inferred type. For implied variables, the type is completely determined by the syntax of the output language, so implied casts won't work in this case. For most of these cases, the algorithm just changes the type to that dictated by syntax and gets back on track at the next explicit variable in the flow. It tries to avoid losing pointer types however because any CPUI_PTRADD mst have a pointer input. In this case, it casts to the necessary pointer type immediately.

Member Function Documentation

◆ apply()

int4 ghidra::ActionSetCasts::apply ( Funcdata & data )

virtual

Make a single attempt to apply this Action.

This is the main entry point for applying changes to a function that are specific to this Action. The method can inspect whatever it wants to decide if the Action does or does not apply. Changes are indicated by incrementing the count field.

Parameters

data	is the function to inspect/modify

Returns: 0 for a complete application, -1 for a partial completion (due to breakpoint)

Implements ghidra::Action.

References ghidra::AddrSpace::addressToByteInt(), ghidra::BlockBasic::beginOp(), ghidra::PcodeOp::code(), ghidra::CPUI_CAST, ghidra::CPUI_COPY, ghidra::CPUI_INT_ADD, ghidra::CPUI_LOAD, ghidra::CPUI_PTRADD, ghidra::CPUI_PTRSUB, ghidra::CPUI_STORE, ghidra::BlockBasic::endOp(), ghidra::Funcdata::getArch(), ghidra::Funcdata::getBasicBlocks(), ghidra::PrintLanguage::getCastStrategy(), ghidra::Varnode::getHighTypeReadFacing(), ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::Varnode::getOffset(), ghidra::PcodeOp::getOut(), ghidra::TypePointer::getPtrTo(), ghidra::Datatype::getSize(), ghidra::TypePointer::getWordSize(), ghidra::Datatype::isPtrsubMatching(), ghidra::PcodeOp::notPrinted(), ghidra::PcodeOp::numInput(), ghidra::Funcdata::opRemoveInput(), ghidra::Funcdata::opSetOpcode(), ghidra::Funcdata::opUndoPtradd(), ghidra::Architecture::print, ghidra::Funcdata::startCastPhase(), and ghidra::TYPE_PTR.

◆ castInput()

int4 ghidra::ActionSetCasts::castInput	(	PcodeOp *	op,
		int4	slot,
		Funcdata &	data,
		CastStrategy *	castStrategy
	)

staticprivate

Insert cast to produce the input Varnode to a given PcodeOp if necessary.

This method can also mark a Varnode as an explicit integer constant. Guard against chains of casts.

Parameters

op	is the given PcodeOp
slot	is the slot of the input Varnode
data	is the function being analyzed
castStrategy	is used to determine if a cast is necessary

Returns: 1 if a change is made, 0 otherwise

References ghidra::PcodeOp::code(), ghidra::CPUI_CAST, ghidra::Funcdata::forceFacingType(), ghidra::PcodeOp::getAddr(), ghidra::Funcdata::getArch(), ghidra::Varnode::getDef(), ghidra::Varnode::getHigh(), ghidra::PcodeOp::getIn(), ghidra::TypeOp::getInputCast(), ghidra::PcodeOp::getOpcode(), ghidra::Varnode::getSize(), ghidra::HighVariable::getType(), ghidra::Varnode::getType(), ghidra::Funcdata::inheritResolution(), ghidra::Varnode::isConstant(), ghidra::Varnode::isImplied(), ghidra::Varnode::isWritten(), ghidra::Varnode::loneDescend(), ghidra::CastStrategy::markExplicitLongSize(), ghidra::CastStrategy::markExplicitUnsigned(), ghidra::Datatype::needsResolution(), ghidra::Funcdata::newOp(), ghidra::Funcdata::newUniqueOut(), ghidra::Funcdata::opInsertBefore(), ghidra::Funcdata::opSetInput(), ghidra::Funcdata::opSetOpcode(), ghidra::Varnode::setImplied(), and ghidra::Varnode::updateType().

◆ castOutput()

int4 ghidra::ActionSetCasts::castOutput	(	PcodeOp *	op,
		Funcdata &	data,
		CastStrategy *	castStrategy
	)

staticprivate

Insert cast to output Varnode type after given PcodeOp if it is necessary.

Parameters

op	is the given PcodeOp
data	is the function being analyzed
castStrategy	is used to determine if the cast is necessary

Returns: 1 if a cast inserted, 0 otherwise

◆ checkPointerIssues()

void ghidra::ActionSetCasts::checkPointerIssues	(	PcodeOp *	op,
		Varnode *	vn,
		Funcdata &	data
	)

staticprivate

Check if the data-type of the given value being used as a pointer makes sense.

If the data-type is a pointer make sure:

The pointed-to size matches the size of the value being loaded are stored
Any address space attached to the pointer matches the address space of the LOAD/STORE

If any of the conditions are violated, a warning is added to the output.

Parameters

op	is the LOAD/STORE acting on a pointer
vn	is the given value being used as a pointer
data	is the function containing the PcodeOp

References ghidra::PcodeOp::getAddr(), ghidra::AddrSpace::getContain(), ghidra::Varnode::getHighTypeReadFacing(), ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::TypeOp::getName(), ghidra::AddrSpace::getName(), ghidra::PcodeOp::getOpcode(), ghidra::Varnode::getSize(), ghidra::Varnode::getSpaceFromConst(), ghidra::TYPE_PTR, and ghidra::Funcdata::warning().

◆ clone()

virtual Action* ghidra::ActionSetCasts::clone ( const ActionGroupList & grouplist ) const

inlinevirtual

Clone the Action.

If this Action is a member of one of the groups in the grouplist, this returns a clone of the Action, otherwise NULL is returned.

Parameters

grouplist is the list of groups being cloned

Returns: the cloned Action or NULL

Implements ghidra::Action.

References ghidra::ActionStart::apply(), ghidra::ActionGroupList::contains(), and ghidra::Action::getGroup().

◆ insertPtrsubZero()

PcodeOp * ghidra::ActionSetCasts::insertPtrsubZero	(	PcodeOp *	op,
		int4	slot,
		Datatype *	ct,
		Funcdata &	data
	)

staticprivate

Insert a PTRSUB with offset 0 that accesses a field of the given data-type.

The data-type can be a structure, in which case the field at offset zero is being accessed. The data-type can reference a union, in which case a specific field is being accessed as indicated by Funcdata::getUnionField. The PTRSUB is inserted right before the given PcodeOp. The indicated input Varnode becomes the PTRSUB input, and the PTRSUB output replaces the Varnode in the PcodeOp.

Parameters

op	is the given PcodeOp where the PTRSUB is inserted
slot	is the slot corresponding to the indicated Varnode
ct	is the data-type produced by the PTRSUB
data	is containing Function

Returns: the new PTRSUB op

References ghidra::CPUI_PTRSUB, ghidra::PcodeOp::getAddr(), ghidra::PcodeOp::getIn(), ghidra::Varnode::getSize(), ghidra::Funcdata::newConstant(), ghidra::Funcdata::newOp(), ghidra::Funcdata::newUniqueOut(), ghidra::Funcdata::opInsertBefore(), ghidra::Funcdata::opSetInput(), ghidra::Funcdata::opSetOpcode(), ghidra::Varnode::setImplied(), and ghidra::Varnode::updateType().

◆ isOpIdentical()

bool ghidra::ActionSetCasts::isOpIdentical	(	Datatype *	ct1,
		Datatype *	ct2
	)

staticprivate

Test if two data-types are operation identical.

If, at a source code level, a variable with data-type ct1 can be legally substituted for another variable with data-type ct2, return true. The substitution must be allowed for all possible operations the variable may be involved in.

Parameters

ct1	is the first data-type
ct2	is the second data-type

References ghidra::Datatype::getMetatype(), ghidra::Datatype::getTypedef(), and ghidra::TYPE_PTR.

◆ resolveUnion()

int4 ghidra::ActionSetCasts::resolveUnion	(	PcodeOp *	op,
		int4	slot,
		Funcdata &	data
	)

staticprivate

If the given op reads a pointer to a union, insert the CPUI_PTRSUB that resolves the union.

Parameters

op	is the given PcodeOp
slot	is index of the input slot being read
data	is the containing function

Returns: 1 if a PTRSUB is inserted, 0 otherwise

References ghidra::ResolvedUnion::getDatatype(), ghidra::Varnode::getDef(), ghidra::ResolvedUnion::getFieldNum(), ghidra::Varnode::getHigh(), ghidra::PcodeOp::getIn(), ghidra::Datatype::getMetatype(), ghidra::HighVariable::getType(), ghidra::Varnode::getType(), ghidra::Funcdata::getUnionField(), ghidra::Varnode::isAnnotation(), ghidra::Varnode::isImplied(), ghidra::Varnode::isWritten(), ghidra::Datatype::needsResolution(), ghidra::Datatype::resolveInFlow(), ghidra::Varnode::setImpliedField(), ghidra::Funcdata::setUnionField(), and ghidra::TYPE_PTR.

◆ testStructOffset0()

bool ghidra::ActionSetCasts::testStructOffset0	(	Varnode *	vn,
		PcodeOp *	op,
		Datatype *	ct,
		CastStrategy *	castStrategy
	)

staticprivate

Test if the given cast conflict can be resolved by passing to the first structure field.

Test if the given Varnode data-type is a pointer to a structure and if interpreting the data-type as a pointer to the structure's first field will get it to match the desired data-type.

Parameters

vn	is the given Varnode
op	is the PcodeOp reading the Varnode
ct	is the desired data-type
castStrategy	is used to determine if the data-types are compatible

Returns: true if a pointer to the first field makes sense

References ghidra::TypeStruct::beginField(), ghidra::CastStrategy::castStandard(), ghidra::Varnode::getHighTypeReadFacing(), ghidra::Datatype::getMetatype(), ghidra::TypeStruct::numDepend(), ghidra::TYPE_ARRAY, ghidra::TYPE_PTR, and ghidra::TYPE_STRUCT.

◆ tryResolutionAdjustment()

bool ghidra::ActionSetCasts::tryResolutionAdjustment	(	PcodeOp *	op,
		int4	slot,
		Funcdata &	data
	)

staticprivate

Try to adjust the input and output Varnodes to eliminate a CAST.

If input/output data-types are different, it may be due to late merges. For unions, the CAST can sometimes be eliminated by adjusting the data-type resolutions of the Varnodes relative to the PcodeOp

Parameters

op	is the PcodeOp reading the input Varnode and writing the output Varnode
slot	is the index of the input Varnode
data	is the function

Returns: true if an adjustment is made so that a CAST is no longer needed

References ghidra::Datatype::findCompatibleResolve(), ghidra::Funcdata::getArch(), ghidra::Datatype::getDepend(), ghidra::Varnode::getHigh(), ghidra::PcodeOp::getIn(), ghidra::PcodeOp::getOut(), ghidra::HighVariable::getType(), ghidra::Datatype::needsResolution(), ghidra::Funcdata::setUnionField(), and ghidra::Architecture::types.

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

coreaction.hh
coreaction.cc

Public Member Functions

Static Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ apply()

◆ castInput()

◆ castOutput()

◆ checkPointerIssues()

◆ clone()

◆ insertPtrsubZero()

◆ isOpIdentical()

◆ resolveUnion()

◆ testStructOffset0()

◆ tryResolutionAdjustment()