SegmentOp Class Reference

The segmented address operator. More...

#include <userop.hh>

Inheritance diagram for SegmentOp:

Public Member Functions
	SegmentOp (Architecture *g, const string &nm, int4 ind)
	Constructor. More...
AddrSpace *	getSpace (void) const
	Get the address space being pointed to.
bool	hasFarPointerSupport (void) const
	Return true, if this op supports far pointers.
bool	isForced (void) const
	Return true if exceptions are thrown for bad unification.
int4	getBaseSize (void) const
	Get size in bytes of the base/segment value.
int4	getInnerSize (void) const
	Get size in bytes of the near value.
const VarnodeData &	getResolve (void) const
	Get the default register for resolving indirect segments.
virtual int4	getNumVariableTerms (void) const
	Get the number of input Varnodes expected.
virtual bool	unify (Funcdata &data, PcodeOp *op, vector< Varnode * > &bindlist) const
	Gather the formal input Varnode objects given the root PcodeOp. More...
virtual uintb	execute (const vector< uintb > &input) const
	Compute the output value of this operation, given constant inputs. More...
virtual void	restoreXml (const Element *el)
	Restore the detailed description from an XML stream. More...
Public Member Functions inherited from TermPatternOp
	TermPatternOp (Architecture *g, const string &nm, int4 ind)
	Constructor.
Public Member Functions inherited from UserPcodeOp
	UserPcodeOp (Architecture *g, const string &nm, int4 ind)
	Construct from name and index.
const string &	getName (void) const
	Get the low-level name of the p-code op.
int4	getIndex (void) const
	Get the constant id of the op.
virtual	~UserPcodeOp (void)
	Destructor.
virtual string	getOperatorName (const PcodeOp *op) const
	Get the symbol representing this operation in decompiled code. More...

Static Private Member Functions
static uintb	executeSide (const vector< OpFollow > &follow, uintb input)
	Execute a stream of operations (OpFollow) given a starting input value. More...

Private Attributes
AddrSpace *	spc
	The physical address space into which a segmented pointer points.
int4	baseinsize
	The size in bytes of the base or segment value.
int4	innerinsize
	The size in bytes of the near pointer value.
bool	basepresent
	Is true is a base value must be present in the raw p-code.
bool	forcesegment
	Is true if an exception is thrown when a segment op can't be unified.
bool	supportsfarpointer
	Is true if the joined pair base:near acts as a far pointer.
vector< OpFollow >	basefollow
	Sequence of operations performed on the base value.
vector< OpFollow >	innerfollow
	Sequence of operations performed on the near value.
VarnodeData	constresolve
	How to resolve constant near pointers.

Additional Inherited Members
Protected Attributes inherited from UserPcodeOp
string	name
	Low-level name of p-code operator.
int4	useropindex
	Index passed in the CALLOTHER op.
Architecture *	glb
	Architecture owning the user defined op.

Detailed Description

The segmented address operator.

This op is a placeholder for address mappings involving segments. The map goes between a high-level view of a pointer, consisting of multiple pieces, and a low-level view, where there is only a single absolute pointer. The mapping could be

• a virtual to physical mapping for instance or
• a segment + near pointer to a full address

The output of the operator is always a full low-level pointer. The operator takes two inputs:

• the base or segment and
• the high-level near pointer

High-level analysis can ignore the base/segment and any normalization on the near pointer. Emitted expressions involving this segment op prints only the near portion. Data-type information propagates only through this high-level side.

The decompiler looks for the term-tree defined in SegmentOp and replaces it with the SEGMENTOP operator in any p-code it analyzes. The core routine that looks for the term-tree is unify().

Constructor & Destructor Documentation

SegmentOp()

SegmentOp::SegmentOp	(	Architecture *	g,
		const string &	nm,
		int4	ind
	)

Constructor.

Parameters

g	is the owning Architecture for this instance of the segment operation
nm	is the low-level name of the segment operation
ind	is the constant id identifying the specific CALLOTHER variant

References constresolve, and VarnodeData::space.

Member Function Documentation

execute()

uintb SegmentOp::execute ( const vector< uintb > &  input ) const

virtual

Compute the output value of this operation, given constant inputs.

Parameters

input

is the ordered list of constant inputs

Returns

the resulting value as a constant

Implements TermPatternOp.

References basefollow, basepresent, executeSide(), and innerfollow.

Referenced by RuleSegment::applyOp(), EmulatePcodeOp::executeSegmentOp(), and SegmentedResolver::resolve().

executeSide()

uintb SegmentOp::executeSide ( const vector< OpFollow > &  follow, uintb  input  )

staticprivate

Execute a stream of operations (OpFollow) given a starting input value.

Each operation is performed in turn, with output from the previous becoming input of the next. The final output is returned.

Parameters

follow	is the ordered set of operations to perform
input	is the constant input for the first operation

Returns

the final constant output

References CPUI_INT_AND, and CPUI_INT_LEFT.

Referenced by execute().

restoreXml()

void SegmentOp::restoreXml ( const Element *  el )

virtual

Restore the detailed description from an XML stream.

The details of how a user defined operation behaves can be dynamically configured from an XML tag.

Parameters

el	is the root XML element describing the op

Implements UserPcodeOp.

References basefollow, baseinsize, basepresent, constresolve, forcesegment, UserPcodeOp::getIndex(), Address::getOffset(), UserOpManage::getOp(), Address::getSpace(), AddrSpaceManager::getSpaceByName(), UserPcodeOp::glb, innerfollow, innerinsize, UserPcodeOp::name, VarnodeData::offset, Address::restoreXml(), VarnodeData::size, VarnodeData::space, spc, supportsfarpointer, UserPcodeOp::useropindex, and Architecture::userops.

Referenced by UserOpManage::parseSegmentOp().

unify()

bool SegmentOp::unify ( Funcdata &  data, PcodeOp *  op, vector< Varnode * > &  bindlist  ) const

virtual

Gather the formal input Varnode objects given the root PcodeOp.

Parameters

data	is the function being analyzed
op	is the root operation
bindlist	will hold the ordered list of input Varnodes

Returns

true if the requisite inputs were found

Implements TermPatternOp.

References baseinsize, basepresent, PcodeOp::code(), CPUI_CALLOTHER, PcodeOp::getIn(), Varnode::getOffset(), innerinsize, Varnode::isConstant(), Funcdata::newConstant(), PcodeOp::numInput(), and UserPcodeOp::useropindex.

Referenced by ActionSegmentize::apply().

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

• userop.hh
• userop.cc