A high-level variable modeled as a list of low-level variables, each written once. More...

#include <variable.hh>

Public Types
enum	{ flagsdirty = 1, namerepdirty = 2, typedirty = 4, coverdirty = 8, symboldirty = 0x10, copy_in1 = 0x20, copy_in2 = 0x40, type_finalized = 0x80, unmerged = 0x100 }
	Dirtiness flags for a HighVariable. More...

Public Member Functions
	HighVariable (Varnode *vn)
	Construct a HighVariable with a single member Varnode. More...

Datatype *	getType (void) const
	Get the data-type.

Symbol *	getSymbol (void) const
	Get the Symbol associated with this or null.

SymbolEntry *	getSymbolEntry (void) const

int4	getSymbolOffset (void) const
	Get the SymbolEntry mapping to this or null. More...

int4	numInstances (void) const
	Get the number of member Varnodes this has.

Varnode *	getInstance (int4 i) const
	Get the i-th member Varnode.

void	finalizeDatatype (Datatype *tp)
	Set a final datatype for this variable. More...

void	printCover (ostream &s) const
	Print details of the cover for this (for debug purposes) More...

void	printInfo (ostream &s) const
	Print information about this HighVariable to stream. More...

bool	hasName (void) const
	Check if this HighVariable can be named. More...

Varnode *	getTiedVarnode (void) const
	Find the first address tied member Varnode. More...

Varnode *	getInputVarnode (void) const
	Find (the) input member Varnode. More...

Varnode *	getTypeRepresentative (void) const
	Get a member Varnode with the strongest data-type. More...

Varnode *	getNameRepresentative (void) const
	Get a member Varnode that dictates the naming of this HighVariable. More...

int4	getNumMergeClasses (void) const
	Get the number of speculative merges for this.

bool	isMapped (void) const
	Return true if this is mapped.

bool	isPersist (void) const
	Return true if this is a global variable.

bool	isAddrTied (void) const
	Return true if this is address ties.

bool	isInput (void) const
	Return true if this is an input variable.

bool	isImplied (void) const
	Return true if this is an implied variable.

bool	isSpacebase (void) const
	Return true if this is a spacebase.

bool	isConstant (void) const
	Return true if this is a constant.

bool	isUnaffected (void) const
	Return true if this is an unaffected register.

bool	isExtraOut (void) const
	Return true if this is an extra output.

void	setMark (void) const
	Set the mark on this variable.

void	clearMark (void) const
	Clear the mark on this variable.

bool	isMark (void) const
	Return true if this is marked.

bool	isUnmerged (void) const
	Return true if this has merge problems.

bool	hasCover (void) const
	Determine if this HighVariable has an associated cover. More...

bool	isUnattached (void) const
	Return true if this has no member Varnode.

bool	isTypeLock (void) const
	Return true if this is typelocked.

bool	isNameLock (void) const
	Return true if this is namelocked.

void	saveXml (ostream &s) const
	Save the variable to stream as an XML <high> tag. More...

Static Public Member Functions
static bool	compareName (Varnode vn1, Varnode vn2)
	Determine which given Varnode is most nameable. More...

static bool	compareJustLoc (const Varnode a, const Varnode b)
	Compare based on storage location. More...

Private Member Functions
int4	instanceIndex (const Varnode *vn) const
	Find the index of a specific Varnode member. More...

void	updateFlags (void) const
	(Re)derive boolean properties of this from the member Varnodes More...

void	updateCover (void) const
	(Re)derive the cover of this from the member Varnodes More...

void	updateType (void) const
	(Re)derive the data-type for this from the member Varnodes More...

void	updateSymbol (void) const
	(Re)derive the Symbol and offset for this from member Varnodes

void	setCopyIn1 (void) const
	Mark the existence of one COPY into this.

void	setCopyIn2 (void) const
	Mark the existence of two COPYs into this.

void	clearCopyIns (void) const
	Clear marks indicating COPYs into this.

bool	hasCopyIn1 (void) const
	Is there at least one COPY into this.

bool	hasCopyIn2 (void) const
	Is there at least two COPYs into this.

void	remove (Varnode *vn)
	Remove a member Varnode from this. More...

void	merge (HighVariable *tv2, bool isspeculative)
	Merge another HighVariable into this. More...

void	setSymbol (Varnode *vn) const
	Update Symbol information for this from the given member Varnode. More...

void	setSymbolReference (Symbol *sym, int4 off)
	Attach a reference to a Symbol to this. More...

void	flagsDirty (void) const
	Mark the boolean properties as dirty.

void	coverDirty (void) const
	Mark the cover as dirty.

void	typeDirty (void) const
	Mark the data-type as dirty.

void	setUnmerged (void) const
	Mark this as having merge problems.

Private Attributes
vector< Varnode * >	inst
	The member Varnode objects making up this HighVariable.

int4	numMergeClasses
	Number of different speculative merge classes in this.

uint4	highflags
	Dirtiness flags.

uint4	flags
	Boolean properties inherited from Varnode members.

Datatype *	type
	The data-type for this.

Varnode *	nameRepresentative
	The storage location used to generate a Symbol name.

Cover	wholecover
	The ranges of code addresses covered by this HighVariable.

Symbol *	symbol
	The Symbol this HighVariable is tied to.

int4	symboloffset
	-1=perfect symbol match >=0, offset

Friends
class	Varnode

class	Merge

Detailed Description

A high-level variable modeled as a list of low-level variables, each written once.

In the Static Single Assignment (SSA) representation of a function's data-flow, the Varnode object represents a variable node. This is a low-level variable: it is written to at most once, and there is 1 or more reads. A high-level variable, in the source language may be written to multiple times. We model this idea as a list of Varnode objects, where a different Varnode holds the value of the variable for different parts of the code. The range(s) of code for which a single Varnode holds the high-level variable's value is the cover or range of that Varnode and is modeled by the class Cover. Within a high-level variable, HighVariable, the covers of member Varnode objects should not intersect, as that represents the variable holding two or more different values at the same place in the code. The HighVariable inherits a cover which is the union of the covers of its Varnodes.

Member Enumeration Documentation

anonymous enum

Dirtiness flags for a HighVariable.

The HighVariable inherits its Cover, its data-type, and other boolean properties from its Varnodes. The object holds these explicitly, but the values may become stale as the data-flow transforms. So we keep track of when these inherited values are dirty

Enumerator
flagsdirty	Boolean properties for the HighVariable are dirty.
namerepdirty	The name representative for the HighVariable is dirty.
typedirty	The data-type for the HighVariable is dirty.
coverdirty	The cover for the HighVariable is dirty.
symboldirty	The symbol attachment is dirty.
copy_in1	There exists at least 1 COPY into this HighVariable from other HighVariables.
copy_in2	There exists at least 2 COPYs into this HighVariable from other HighVariables.
type_finalized	Set if a final data-type is locked in and dirtying is disabled.
unmerged	Set if part of a multi-entry Symbol but did not get merged with other SymbolEntrys.

Constructor & Destructor Documentation

HighVariable::HighVariable ( Varnode * vn )

Construct a HighVariable with a single member Varnode.

The new instance starts off with no associate Symbol and all properties marked as dirty.

Parameters

vn	is the single Varnode member

References coverdirty, flags, flagsdirty, Varnode::getSymbolEntry(), highflags, inst, namerepdirty, nameRepresentative, numMergeClasses, Varnode::setHigh(), setSymbol(), symbol, symboloffset, type, and typedirty.

Referenced by setUnmerged().

Member Function Documentation

bool HighVariable::compareJustLoc	(	const Varnode *	a,
		const Varnode *	b
	)

static

Compare based on storage location.

Compare two Varnode objects based just on their storage address

Parameters

a	is the first Varnode to compare
b	is the second Varnode

Returns: true if the first Varnode should be ordered before the second

References Varnode::getAddr().

Referenced by isNameLock(), merge(), and remove().

bool HighVariable::compareName	(	Varnode *	vn1,
		Varnode *	vn2
	)

static

Determine which given Varnode is most nameable.

Given two Varnode (members), sort them based on naming properties:

A Varnode with an assigned name is preferred
An unaffected Varnode is preferred
A global Varnode is preferred
An input Varnode is preferred
An address tied Varnode is preferred
A non-temporary Varnode is preferred
A written Varnode is preferred
An earlier Varnode is preferred

Returns: true if the second Varnode's name would override the first's

References Varnode::getDef(), Varnode::getSpace(), PcodeOp::getTime(), AddrSpace::getType(), IPTR_INTERNAL, Varnode::isAddrTied(), Varnode::isInput(), Varnode::isNameLock(), Varnode::isPersist(), Varnode::isUnaffected(), and Varnode::isWritten().

Referenced by getNameRepresentative(), and isNameLock().

void HighVariable::finalizeDatatype ( Datatype * tp )

Set a final datatype for this variable.

The data-type its dirtying mechanism is disabled. The data-type will not change, unless this method is called again.

Parameters

tp	is the data-type to set

References highflags, type, and type_finalized.

Referenced by getInstance(), and Funcdata::syncVarnodesWithSymbol().

Varnode * HighVariable::getInputVarnode ( void ) const

Find (the) input member Varnode.

This should only be called if isInput() returns true. If there is no input member, this will throw an exception.

Returns: the input Varnode member

References inst, and isInput().

Referenced by hasName(), Merge::mergeTestAdjacent(), and printCover().

Varnode * HighVariable::getNameRepresentative ( void ) const

Get a member Varnode that dictates the naming of this HighVariable.

Members are scored based the properties that are most dominating in choosing a name.

Returns: the highest scoring Varnode member

References compareName(), highflags, inst, namerepdirty, and nameRepresentative.

Referenced by ActionNameVars::linkSymbols(), printCover(), PrintLanguage::pushVnExplicit(), PrintLanguage::pushVnLHS(), and saveXml().

SymbolEntry * HighVariable::getSymbolEntry ( void ) const

Assuming there is a Symbol attached to this, run through the Varnode members until we find one with a SymbolEntry corresponding to the Symbol and return it.

Returns: the SymbolEntry that mapped the Symbol to this or null if no Symbol is attached

References SymbolEntry::getSymbol(), inst, and symbol.

Referenced by getSymbol(), and PrintC::pushSymbol().

int4 HighVariable::getSymbolOffset ( void ) const

inline

Get the SymbolEntry mapping to this or null.

Get the Symbol offset associated with this

References symboloffset.

Referenced by ActionNameVars::linkSymbols(), Merge::mergeTestRequired(), PrintC::opPtrsub(), PrintLanguage::pushVnExplicit(), and PrintLanguage::pushVnLHS().

Varnode * HighVariable::getTiedVarnode ( void ) const

Find the first address tied member Varnode.

This should only be called if isAddrTied() returns true. If there is no address tied member, this will throw an exception.

Returns: the first address tied member

References inst, and isAddrTied().

Referenced by MapState::gatherHighs(), Merge::markInternalCopies(), Merge::mergeTestRequired(), and printCover().

Varnode * HighVariable::getTypeRepresentative ( void ) const

Get a member Varnode with the strongest data-type.

Find the member Varnode with the most specialized data-type, handling bool specially. Boolean data-types are specialized in the data-type lattice, but not all byte values are boolean values. Within the Varnode/PcodeOp tree, the bool data-type can only propagate to a Varnode if it is verified to only take the boolean values 0 and 1. Since the data-type representative represents the type of all instances, if any instance is not boolean, then the HighVariable cannot be boolean, even though bool is more specialized. This method uses Datatype::typeOrderBool() to implement the special handling.

Returns: the representative member

References Varnode::getType(), inst, Varnode::isTypeLock(), and Datatype::typeOrderBool().

Referenced by printCover(), and updateType().

bool HighVariable::hasCover ( void ) const

inline

Determine if this HighVariable has an associated cover.

Constant and annotation variables do not have a cover

Returns: true if this has a cover

References Varnode::annotation, Varnode::constant, Varnode::insert, and updateFlags().

Referenced by Merge::mergeTest(), and updateCover().

bool HighVariable::hasName ( void ) const

Check if this HighVariable can be named.

All Varnode objects are assigned a HighVariable, including those that don't get names like indirect variables, constants, and annotations. Determine if this, as inherited from its member Varnodes, can have a name.

Returns: true if this can have a name

References getInputVarnode(), Varnode::hasCover(), inst, Varnode::isIllegalInput(), Varnode::isImplied(), Varnode::isIndirectOnly(), isInput(), Varnode::isSpacebase(), and isUnaffected().

Referenced by ActionNameVars::linkSymbols(), and printCover().

int4 HighVariable::instanceIndex ( const Varnode * vn ) const

private

Find the index of a specific Varnode member.

Find the index, for use with getInstance(), that will retrieve the given Varnode member

Parameters

vn	is the given Varnode member

Returns: the index of the member or -1 if it is not a member

References inst.

void HighVariable::merge	(	HighVariable *	tv2,
		bool	isspeculative
	)

private

Merge another HighVariable into this.

The lists of members are merged and the other HighVariable is deleted.

Parameters

tv2	is the other HighVariable to merge into this
isspeculative	is true to keep the new members in separate merge classes

References compareJustLoc(), coverdirty, flagsdirty, Varnode::getMergeGroup(), highflags, inst, Cover::merge(), namerepdirty, numMergeClasses, Varnode::setHigh(), symbol, symboldirty, symboloffset, typedirty, and wholecover.

Referenced by Merge::buildDominantCopy(), hasCopyIn2(), and Merge::merge().

void HighVariable::printCover ( ostream & s ) const

inline

Print details of the cover for this (for debug purposes)

Parameters

s	is the output stream

References coverdirty, getInputVarnode(), getNameRepresentative(), getTiedVarnode(), getTypeRepresentative(), hasName(), Cover::print(), and printInfo().

void HighVariable::printInfo ( ostream & s ) const

Print information about this HighVariable to stream.

This is generally used for debug purposes.

Parameters

s	is the output stream

References Varnode::getMergeGroup(), Symbol::getName(), inst, Varnode::printInfo(), Datatype::printRaw(), symbol, symboloffset, type, and updateType().

Referenced by printCover().

void HighVariable::remove ( Varnode * vn )

private

Remove a member Varnode from this.

Search for the given Varnode and cut it out of the list, marking all properties as dirty.

Parameters

vn	is the given Varnode member to remove

References compareJustLoc(), coverdirty, flagsdirty, Varnode::getSymbolEntry(), highflags, inst, namerepdirty, symboldirty, and typedirty.

Referenced by Merge::buildDominantCopy(), and Varnode::~Varnode().

void HighVariable::saveXml ( ostream & s ) const

Save the variable to stream as an XML <high> tag.

Parameters

s	is the output stream to write XML to

References a_v(), a_v_b(), a_v_i(), a_v_u(), Symbol::getCategory(), Varnode::getCreateIndex(), Symbol::getId(), getNameRepresentative(), isAddrTied(), isConstant(), isImplied(), isPersist(), isSpacebase(), isTypeLock(), symbol, and symboloffset.

Referenced by isNameLock(), and Funcdata::saveXmlHigh().

void HighVariable::setSymbol ( Varnode * vn ) const

private

Update Symbol information for this from the given member Varnode.

The given Varnode must be a member and must have a non-null SymbolEntry.

References SymbolEntry::getAddr(), Varnode::getAddr(), Symbol::getName(), SymbolEntry::getOffset(), Varnode::getSize(), SymbolEntry::getSymbol(), Varnode::getSymbolEntry(), highflags, SymbolEntry::isDynamic(), SymbolEntry::isPiece(), Address::overlap(), symbol, symboldirty, and symboloffset.

Referenced by hasCopyIn2(), HighVariable(), and updateSymbol().

void HighVariable::setSymbolReference	(	Symbol *	sym,
		int4	off
	)

private

Attach a reference to a Symbol to this.

Link information to this from a Symbol that is not attached to a member Varnode. This only works for a HighVariable with a constant member Varnode. This used when there is a constant address reference to the Symbol and the Varnode holds the reference, not the actual value of the Symbol.

Parameters

sym	is the given Symbol to attach
off	is the byte offset into the Symbol of the reference

References highflags, symbol, symboldirty, and symboloffset.

Referenced by hasCopyIn2().

void HighVariable::updateCover ( void ) const

private

(Re)derive the cover of this from the member Varnodes

Only update if the cover is marked as dirty. Merge the covers of all Varnode instances. This is only called by the Merge class which knows when to call it properly.

References Cover::clear(), coverdirty, hasCover(), highflags, inst, Cover::merge(), and wholecover.

Referenced by Merge::merge(), and Merge::updateHigh().

void HighVariable::updateFlags ( void ) const

private

(Re)derive boolean properties of this from the member Varnodes

Only update if flags are marked as dirty. Generally if any member Varnode possesses the property, this HighVariable should inherit it. The Varnode::typelock field is not set here, but in updateType().

References Varnode::directwrite, flags, flagsdirty, highflags, inst, Varnode::mark, and Varnode::typelock.

Referenced by hasCover(), isAddrTied(), isConstant(), isExtraOut(), isImplied(), isInput(), isMapped(), isNameLock(), isPersist(), isSpacebase(), and isUnaffected().