Analyze change to the stack pointer across sub-function calls. More...

#include <coreaction.hh>

Inheritance diagram for ActionStackPtrFlow:

Public Member Functions
	ActionStackPtrFlow (const string &g, AddrSpace *ss)
	Constructor.

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

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 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...

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	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 void	saveXml (ostream &s) const
	Save specifics of this action to stream.

virtual void	restoreXml (const Element el, Funcdata fd)
	Load specifics of action from XML.

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	analyzeExtraPop (Funcdata &data, AddrSpace *stackspace, int4 spcbase)
	Calculate stack-pointer change across undetermined sub-functions. More...

static bool	isStackRelative (Varnode spcbasein, Varnode vn, uintb &constval)
	Is the given Varnode defined as a pointer relative to the stack-pointer? More...

static bool	adjustLoad (Funcdata &data, PcodeOp loadop, PcodeOp storeop)
	Adjust the LOAD where the stack-pointer alias has been recovered. More...

static int4	repair (Funcdata &data, AddrSpace id, Varnode spcbasein, PcodeOp *loadop, uintb constz)
	Link LOAD to matching STORE of a constant. More...

static int4	checkClog (Funcdata &data, AddrSpace *id, int4 spcbase)
	Find any stack pointer clogs and pass it on to the repair routines. More...

Private Attributes
AddrSpace *	stackspace
	Stack space associated with stack-pointer register.

bool	analysis_finished
	True if analysis already performed.

Additional Inherited Members
Public Types inherited from 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 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 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

Analyze change to the stack pointer across sub-function calls.

Member Function Documentation

◆ adjustLoad()

bool ActionStackPtrFlow::adjustLoad	(	Funcdata &	data,
		PcodeOp *	loadop,
		PcodeOp *	storeop
	)

staticprivate

Adjust the LOAD where the stack-pointer alias has been recovered.

We've matched a LOAD with its matching store, now convert the LOAD op to a COPY of what was stored.

Parameters

data	is the function being analyzed
loadop	is the LOAD op to adjust
storeop	is the matching STORE op

Returns: true if the adjustment is successful

References CPUI_COPY, PcodeOp::getIn(), Varnode::getOffset(), Varnode::getSize(), Varnode::isConstant(), Varnode::isFree(), Funcdata::newConstant(), Funcdata::opRemoveInput(), Funcdata::opSetInput(), and Funcdata::opSetOpcode().

Referenced by repair().

◆ analyzeExtraPop()

void ActionStackPtrFlow::analyzeExtraPop	(	Funcdata &	data,
		AddrSpace *	stackspace,
		int4	spcbase
	)

staticprivate

Calculate stack-pointer change across undetermined sub-functions.

If there are sub-functions for which extra pop is not explicit, do full linear analysis to (attempt to) recover the values.

Parameters

data	is the function to analyze
stackspace	is the space associated with the stack-pointer
spcbase	is the index (relative to the stackspace) of the stack-pointer

References StackSolver::build(), calc_mask(), PcodeOp::code(), CPUI_INDIRECT, CPUI_INT_ADD, Architecture::defaultfp, Architecture::evalfp_called, LowlevelError::explain, ProtoModel::extrapop_unknown, Varnode::getAddr(), Funcdata::getArch(), Funcdata::getCallSpecs(), StackSolver::getCompanion(), Varnode::getDef(), ProtoModel::getExtraPop(), PcodeOp::getIn(), AddrSpace::getName(), StackSolver::getNumVariables(), PcodeOp::getOpFromConst(), Varnode::getSize(), StackSolver::getSolution(), Varnode::getSpace(), AddrSpace::getType(), StackSolver::getVariable(), IPTR_IOP, Funcdata::newConstant(), Funcdata::opSetAllInput(), Funcdata::opSetOpcode(), StackSolver::solve(), stackspace, and Funcdata::warningHeader().

Referenced by apply().

◆ apply()

int4 ActionStackPtrFlow::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 Action.

References analysis_finished, analyzeExtraPop(), checkClog(), Action::count, and stackspace.

◆ checkClog()

int4 ActionStackPtrFlow::checkClog	(	Funcdata &	data,
		AddrSpace *	id,
		int4	spcbase
	)

staticprivate

Find any stack pointer clogs and pass it on to the repair routines.

A stack pointer clog is a constant addition to the stack-pointer, but where the constant comes from the stack.

Parameters

data	is the function to analyze
id	is the stack space
spcbase	is the index of the stack-pointer relative to the stack space

Returns: the number of clogs that were repaired

References Funcdata::beginLoc(), calc_mask(), PcodeOp::code(), CPUI_INT_ADD, CPUI_INT_MULT, CPUI_LOAD, Funcdata::endLoc(), Varnode::getDef(), PcodeOp::getIn(), Varnode::getOffset(), Varnode::getSize(), AddrSpace::getSpacebase(), Varnode::isConstant(), Varnode::isInput(), isStackRelative(), Varnode::isWritten(), and repair().

Referenced by apply().

◆ clone()

virtual Action* ActionStackPtrFlow::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 Action.

References ActionStackPtrFlow(), ActionGroupList::contains(), Action::getGroup(), and stackspace.

◆ isStackRelative()

bool ActionStackPtrFlow::isStackRelative	(	Varnode *	spcbasein,
		Varnode *	vn,
		uintb &	constval
	)

staticprivate

Is the given Varnode defined as a pointer relative to the stack-pointer?

Return true if -vn- is defined as the stackpointer input plus a constant (or zero) This works through the general case and the special case when the constant is zero. The constant value is passed-back to the caller.

Parameters

spcbasein	is the Varnode holding the input value of the stack-pointer
vn	is the Varnode to check for relativeness
constval	is a reference for passing back the constant offset

Returns: true if vn is stack relative

References PcodeOp::code(), CPUI_INT_ADD, Varnode::getDef(), PcodeOp::getIn(), Varnode::getOffset(), Varnode::isConstant(), and Varnode::isWritten().

Referenced by checkClog(), and repair().

◆ repair()

int4 ActionStackPtrFlow::repair	(	Funcdata &	data,
		AddrSpace *	id,
		Varnode *	spcbasein,
		PcodeOp *	loadop,
		uintb	constz
	)

staticprivate

Link LOAD to matching STORE of a constant.

Try to find STORE op using same stack relative pointer as a given LOAD op. If we find it and the STORE stores a constant, change the LOAD to a COPY.

Parameters

data	is the function owning the LOAD
id	is the stackspace
spcbasein	is the stack-pointer
loadop	is the given LOAD op
constz	is the stack relative offset of the LOAD pointer

Returns: 1 if we successfully change LOAD to COPY, 0 otherwise

References adjustLoad(), BlockBasic::beginOp(), PcodeOp::code(), CPUI_STORE, BlockBasic::endOp(), PcodeOp::getBasicIter(), PcodeOp::getIn(), FlowBlock::getIn(), PcodeOp::getOut(), PcodeOp::getParent(), Varnode::getSize(), Varnode::getSpace(), PcodeOp::isCall(), isStackRelative(), and FlowBlock::sizeIn().

Referenced by checkClog().

◆ reset()

virtual void ActionStackPtrFlow::reset ( Funcdata & data )

inlinevirtual

Reset the Action for a new function.

Parameters

data	is the new function this Action may affect

Reimplemented from Action.

References analysis_finished.

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

coreaction.hh
coreaction.cc

Public Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ adjustLoad()

◆ analyzeExtraPop()

◆ apply()

◆ checkClog()

◆ clone()

◆ isStackRelative()

◆ repair()

◆ reset()