ghidra::BitFieldTransform Class Reference

Class for transforming bitfield expressions. More...

#include <bitfield.hh>

Inheritance diagram for ghidra::BitFieldTransform:

Public Member Functions
	BitFieldTransform (Funcdata *f, Datatype *dt, int4 off)
	Constructor setting up basic info about bitfield data-type.

Protected Member Functions
void	establishFields (Varnode *vn, bool followHoles)
	Build worklist for each bitfield overlapped by given Varnode.
Datatype *	buildPartialType (void)
	Build the (partial) data-type associated with the root bitfield container.

Static Protected Member Functions
static bool	findOverwrite (Varnode *vn, BlockBasic *bl, const BitRange &range)
	Return true if specified bits in a Varnode are overwritten in the same basic block.

Protected Attributes
Funcdata *	func
	The containing function.
TypeStruct *	parentStruct
	Structure owning the bitfields.
list< BitFieldNodeState >	workList
	Fields that are being followed.
int4	initialOffset
	Byte offset into parent structure.
int4	containerSize
	Size of Varnode containing bitfields.
bool	isBigEndian
	Endianness associated with bitfields.

Detailed Description

Class for transforming bitfield expressions.

For both insertion and extraction, establish the bitfields that need to be traced.

Constructor & Destructor Documentation

BitFieldTransform()

ghidra::BitFieldTransform::BitFieldTransform	(	Funcdata *	f,
		Datatype *	dt,
		int4	off
	)

Constructor setting up basic info about bitfield data-type.

Parameters

f	is the containing function
dt	is the bitfield data-type
off	is any initial byte offset into the data-type for the root Varnode

References containerSize, func, ghidra::Funcdata::getArch(), ghidra::AddrSpaceManager::getDefaultDataSpace(), ghidra::Datatype::getMetatype(), ghidra::TypePartialStruct::getOffset(), ghidra::TypePartialStruct::getParent(), initialOffset, isBigEndian, ghidra::AddrSpace::isBigEndian(), parentStruct, ghidra::TYPE_PARTIALSTRUCT, and ghidra::TYPE_STRUCT.

Member Function Documentation

buildPartialType()

Datatype * ghidra::BitFieldTransform::buildPartialType ( void  )

protected

Build the (partial) data-type associated with the root bitfield container.

Returns

the bitfield data-type

References containerSize, func, ghidra::Funcdata::getArch(), ghidra::Datatype::getSize(), ghidra::TypeFactory::getTypePartialStruct(), initialOffset, parentStruct, and ghidra::Architecture::types.

Referenced by ghidra::BitFieldInsertTransform::apply(), and ghidra::BitFieldPullTransform::apply().

establishFields()

void ghidra::BitFieldTransform::establishFields ( Varnode *  vn, bool  followHoles  )

protected

Build worklist for each bitfield overlapped by given Varnode.

A BitFieldNodeState is constructed for each bitfield that the Varnode overlaps. Holes between bitfields can also have a BitFieldNodeState.

Parameters

vn	is the given Varnode
followHoles	is true if a record for each hole should be created

References ghidra::BitFieldTriple::bitfield, ghidra::TypeBitField::bits, ghidra::TypeStruct::collectBitFields(), ghidra::BitFieldTriple::compare(), ghidra::Varnode::getSize(), initialOffset, isBigEndian, ghidra::BitRange::numBits, ghidra::BitRange::overlapTest(), parentStruct, ghidra::BitRange::translateLSB(), and workList.

Referenced by ghidra::BitFieldInsertTransform::BitFieldInsertTransform(), and ghidra::BitFieldPullTransform::BitFieldPullTransform().

findOverwrite()

bool ghidra::BitFieldTransform::findOverwrite ( Varnode *  vn, BlockBasic *  bl, const BitRange &  range  )

staticprotected

Return true if specified bits in a Varnode are overwritten in the same basic block.

This assumes other unspecified bits within the given Varnode are preserved at the point of overwrite.

Parameters

vn	is the given Varnode
bl	is the given block
range	specifies the bits within the Varnode

Returns

true if the bits are used

References ghidra::Varnode::beginDescend(), ghidra::BitRange::byteOffset, ghidra::BitRange::byteSize, ghidra::PcodeOp::code(), ghidra::Address::containedBy(), ghidra::CPUI_COPY, ghidra::CPUI_INDIRECT, ghidra::CPUI_INSERT, ghidra::CPUI_INT_AND, ghidra::CPUI_INT_LEFT, ghidra::CPUI_INT_NEGATE, ghidra::CPUI_INT_OR, ghidra::CPUI_INT_RIGHT, ghidra::CPUI_INT_XOR, ghidra::CPUI_PIECE, ghidra::Varnode::endDescend(), ghidra::BitRange::extendBytes(), ghidra::Varnode::getAddr(), ghidra::PcodeOp::getIn(), ghidra::Varnode::getOffset(), ghidra::PcodeOp::getOut(), ghidra::PcodeOp::getParent(), ghidra::InsertExpression::getRangeMask(), ghidra::Varnode::getSize(), ghidra::Varnode::hasNoDescend(), ghidra::BitRange::intersectMask(), ghidra::Varnode::isConstant(), ghidra::Varnode::loneDescend(), ghidra::BitRange::minimizeContainer(), ghidra::BitRange::numBits, and ghidra::BitRange::shift().

Referenced by ghidra::BitFieldInsertTransform::isOverwrittenPartial().

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

• bitfield.hh
• bitfield.cc