PcodeOp Class Reference

Lowest level operation of the p-code language. More...

#include <op.hh>

Public Types
enum	{   startbasic = 1, branch = 2, call = 4, returns = 0x8,   nocollapse = 0x10, dead = 0x20, marker = 0x40, booloutput = 0x80,   boolean_flip = 0x100, fallthru_true = 0x200, indirect_source = 0x400, coderef = 0x800,   startmark = 0x1000, mark = 0x2000, commutative = 0x4000, unary = 0x8000,   binary = 0x10000, special = 0x20000, ternary = 0x40000, splittingbranch = 0x80000,   nonprinting = 0x100000, halt = 0x200000, badinstruction = 0x400000, unimplemented = 0x800000,   noreturn = 0x1000000, missing = 0x2000000, spacebase_ptr = 0x4000000, indirect_creation = 0x8000000,   calculated_bool = 0x10000000, has_callspec = 0x20000000, ptrflow = 0x40000000, indirect_store = 0x80000000 }
enum	{   special_prop = 1, special_print = 2, modified = 4, warning = 8,   incidental_copy = 0x10, is_cpool_transformed = 0x20 }

Public Member Functions
	PcodeOp (int4 s, const SeqNum &sq)
	Construct an unattached PcodeOp. More...
	~PcodeOp (void)
	Destructor.
int4	numInput (void) const
	Get the number of inputs to this op.
Varnode *	getOut (void)
	Get the output Varnode of this op or null.
const Varnode *	getOut (void) const
	Get the output Varnode of this op or null.
Varnode *	getIn (int4 slot)
	Get a specific input Varnode to this op.
const Varnode *	getIn (int4 slot) const
	Get a specific input Varnode to this op.
const BlockBasic *	getParent (void) const
	Get the parent basic block.
BlockBasic *	getParent (void)
	Get the parent basic block.
const Address &	getAddr (void) const
	Get the instruction address associated with this op.
uintm	getTime (void) const
	Get the time index indicating when this op was created.
const SeqNum &	getSeqNum (void) const
	Get the sequence number associated with this op.
list< PcodeOp * >::iterator	getInsertIter (void) const
	Get position within alive/dead list.
list< PcodeOp * >::iterator	getBasicIter (void) const
int4	getSlot (const Varnode *vn) const
	Get the slot number of the indicated input varnode.
int4	getRepeatSlot (const Varnode *vn, int4 firstSlot, list< PcodeOp * >::const_iterator iter) const
	Find the slot for a given Varnode, which may be take up multiple input slots. More...
uint4	getEvalType (void) const
	Get the evaluation type of this op.
uint4	getHaltType (void) const
	Get type which indicates unusual halt in control-flow.
bool	isDead (void) const
	Return true if this op is dead.
bool	isAssignment (void) const
	Return true is this op has an output.
bool	isCall (void) const
bool	isCallWithoutSpec (void) const
	Return true if this op acts as call but does not have a full specification.
bool	isMarker (void) const
	Return true is a special SSA form op.
bool	isIndirectCreation (void) const
	Return true if op creates a varnode indirectly.
bool	isIndirectStore (void) const
bool	notPrinted (void) const
	Return true if this op is not directly represented in C output.
bool	isBoolOutput (void) const
	Return true if this op produces a boolean output.
bool	isBranch (void) const
bool	isCallOrBranch (void) const
	Return true if this op is a call or branch.
bool	isFlowBreak (void) const
	Return true if this op breaks fall-thru flow.
bool	isBooleanFlip (void) const
	Return true if this op flips the true/false meaning of its control-flow branching.
bool	isFallthruTrue (void) const
	Return true if the fall-thru branch is taken when the boolean input is true.
bool	isCodeRef (void) const
	Return true if the first input is a code reference.
bool	isInstructionStart (void) const
	Return true if this starts an instruction.
bool	isBlockStart (void) const
	Return true if this starts a basic block.
bool	isModified (void) const
	Return true if this is modified by the current action.
bool	isMark (void) const
	Return true if this op has been marked.
void	setMark (void) const
	Set the mark on this op.
bool	isWarning (void) const
	Return true if a warning has been generated for this op.
void	clearMark (void) const
	Clear any mark on this op.
bool	isIndirectSource (void) const
	Return true if this causes an INDIRECT.
void	setIndirectSource (void)
	Mark this op as source of INDIRECT.
void	clearIndirectSource (void)
	Clear INDIRECT source flag.
bool	isPtrFlow (void) const
	Return true if this produces/consumes ptrs.
void	setPtrFlow (void)
	Mark this op as consuming/producing ptrs.
bool	isSplitting (void) const
	Return true if this branch splits.
bool	doesSpecialPropagation (void) const
	Return true if this does datatype propagation.
bool	doesSpecialPrinting (void) const
	Return true if this needs to special printing.
bool	isIncidentalCopy (void) const
bool	isCalculatedBool (void) const
	Return true if output is 1-bit boolean.
bool	isCpoolTransformed (void) const
	Return true if we have already examined this cpool.
bool	isCollapsible (void) const
bool	usesSpacebasePtr (void) const
	Return true if this LOADs or STOREs from a dynamic spacebase pointer.
uintm	getCseHash (void) const
	Return hash indicating possibility of common subexpression elimination. More...
bool	isCseMatch (const PcodeOp *op) const
	Return true if this and op represent common subexpressions. More...
TypeOp *	getOpcode (void) const
	Get the opcode for this op.
OpCode	code (void) const
	Get the opcode id (enum) for this op.
bool	isCommutative (void) const
	Return true if inputs commute.
uintb	collapse (bool &markedInput) const
	Calculate the constant output produced by this op. More...
void	collapseConstantSymbol (Varnode *newConst) const
	Propagate constant symbol from inputs to given output. More...
PcodeOp *	nextOp (void) const
	Return the next op in the control-flow from this or null.
PcodeOp *	previousOp (void) const
	Return the previous op within this op's basic block or null. More...
PcodeOp *	target (void) const
	Return starting op for instruction associated with this op. More...
uintb	getNZMaskLocal (bool cliploop) const
	Calculate known zero bits for output to this op. More...
int4	compareOrder (const PcodeOp *bop) const
	Compare the control-flow order of this and bop. More...
void	printRaw (ostream &s) const
	Print raw info about this op to stream.
const string &	getOpName (void) const
	Return the name of this op.
void	printDebug (ostream &s) const
	Print debug description of this op to stream. More...
void	saveXml (ostream &s) const
Datatype *	outputTypeLocal (void) const
	Calculate the local output type.
Datatype *	inputTypeLocal (int4 slot) const
	Calculate the local input type.
bool	markExplicitUnsigned (int4 slot)
	Decide on unsignedness printing.
bool	inheritsSign (void) const
	Does this token inherit its sign from operands.

Static Public Member Functions
static PcodeOp *	getOpFromConst (const Address &addr)
	Retrieve the PcodeOp encoded as the address addr.

Private Member Functions
void	setOpcode (TypeOp *t_op)
	Set the opcode for this PcodeOp. More...
void	setOutput (Varnode *vn)
	Set the output Varnode of this op.
void	clearInput (int4 slot)
	Clear a specific input Varnode to null.
void	setInput (Varnode *vn, int4 slot)
	Set a specific input Varnode.
void	setFlag (uint4 fl)
	Set specific boolean attribute(s) on this op.
void	clearFlag (uint4 fl)
	Clear specific boolean attribute(s)
void	setAdditionalFlag (uint4 fl)
	Set specific boolean attribute.
void	clearAdditionalFlag (uint4 fl)
	Clear specific boolean atribute.
void	flipFlag (uint4 fl)
	Flip the setting of specific boolean attribute(s)
void	setNumInputs (int4 num)
	Make sure this op has num inputs. More...
void	removeInput (int4 slot)
	Eliminate a specific input Varnode. More...
void	insertInput (int4 slot)
	Make room for a new input Varnode at a specific position. More...
void	setOrder (uintm ord)
	Order this op within the ops for a single instruction.
void	setParent (BlockBasic *p)
	Set the parent basic block of this op.
void	setBasicIter (list< PcodeOp * >::iterator iter)
	Store the iterator into this op's basic block.

Private Attributes
TypeOp *	opcode
	Pointer to class providing behavioral details of the operation.
uint4	flags
	Collection of boolean attributes on this op.
uint4	addlflags
	Additional boolean attributes for this op.
SeqNum	start
	What instruction address is this attached to.
BlockBasic *	parent
	Basic block in which this op is contained.
list< PcodeOp * >::iterator	basiciter
	Iterator within basic block.
list< PcodeOp * >::iterator	insertiter
	Position in alive/dead list.
list< PcodeOp * >::iterator	codeiter
	Position in opcode list.
Varnode *	output
	The one possible output Varnode of this op.
vector< Varnode * >	inrefs
	The ordered list of input Varnodes for this op.

Friends
class	BlockBasic
class	Funcdata
class	PcodeOpBank
class	VarnodeBank

Detailed Description

Lowest level operation of the p-code language.

The philosophy here is to have only one version of any type of operation, and to be completely explicit about all effects. All operations except the control flow operations have exactly one explicit output. Any given operation can have multiple inputs, but all are listed explicitly.

Input and output size for an operation are specified explicitly. All inputs must be of the same size. Except for the above restrictions, input and output can be any size in bytes.

P-code can be either big or little endian, this is determined by the language being translated from

Member Enumeration Documentation

anonymous enum

Boolean attributes (flags) that can be placed on a PcodeOp. Even though this enum is public, these are all set and read internally, although many are read publicly via get or is methods.

Enumerator
startbasic	This instruction starts a basic block.
branch	This instruction is a branch.
call	This instruction calls a subroutine.
returns	This instruction returns to caller.
nocollapse	This op cannot be collapsed further.
dead	This operation is dead.
marker	special placeholder op (multiequal or indirect) or CPUI_COPY between different copies of same variable
booloutput	Boolean operation.
boolean_flip	Set if condition must be false to take branch.
fallthru_true	Set if fallthru happens on true condition.
indirect_source	Op is source of (one or more) CPUI_INDIRECTs.
coderef	The first parameter to this op is a coderef.
startmark	This op is the first in its instruction.
mark	Used by many algorithms that need to detect loops or avoid repeats.
commutative	Order of input parameters does not matter.
unary	Evaluate as unary expression.
binary	Evaluate as binary expression.
special	Cannot be evaluated (without special processing)
ternary	Evaluate as ternary operator (or higher)
splittingbranch	Dead edge cannot be removed as it splits.
nonprinting	Op should not be directly printed as source.
halt	instruction causes processor or process to halt
badinstruction	placeholder for bad instruction data
unimplemented	placeholder for unimplemented instruction
noreturn	placeholder for previous call that doesn't exit
missing	ops at this address were not generated
spacebase_ptr	Loads or stores from a dynamic pointer into a spacebase.
indirect_creation	Output varnode is created by indirect effect.
calculated_bool	Output has been determined to be a 1-bit boolean value.
has_callspec	Op has a call specification associated with it.
ptrflow	Op consumes or produces a ptr.
indirect_store	CPUI_INDIRECT is caused by CPUI_STORE.

anonymous enum

Enumerator
special_prop	Does some special form of datatype propagation.
special_print	Op is marked for special printing.
modified	This op has been modified by the current action.
warning	Warning has been generated for this op.
incidental_copy	Treat this as incidental for parameter recovery algorithms.
is_cpool_transformed	Have we checked for cpool transforms.

Constructor & Destructor Documentation

PcodeOp::PcodeOp	(	int4	s,
		const SeqNum &	sq
	)

Construct an unattached PcodeOp.

Construct a completely unattached PcodeOp. Space is reserved for input and output Varnodes but all are set initially to null.

Parameters

s	indicates the number of input slots reserved
sq	is the sequence number to associate with the new PcodeOp

References addlflags, flags, inrefs, opcode, output, and parent.

Referenced by PcodeOpBank::create().

Member Function Documentation

uintb PcodeOp::collapse

(

bool &

markedInput

)

const

Calculate the constant output produced by this op.

Assuming all the inputs to this op are constants, compute the constant result of evaluating this op on this inputs. If one if the inputs has attached symbol information, pass-back "the fact of" as we may want to propagate the info to the new constant. Throw an exception if a constant result cannot be produced.

Parameters

markedInput

will pass-back whether or not one of the inputs is a marked constant

Returns

the constant result

References binary, TypeOp::evaluateBinary(), TypeOp::evaluateUnary(), getEvalType(), getIn(), Varnode::getOffset(), Varnode::getSize(), Varnode::getSymbolEntry(), opcode, output, and unary.

Referenced by RuleCollapseConstants::applyOp().

void PcodeOp::collapseConstantSymbol

(

Varnode *

newConst

)

const

Propagate constant symbol from inputs to given output.

Knowing that this PcodeOp has collapsed its constant inputs, one of which has symbol content, figure out if the symbol should propagate to the new given output constant.

Parameters

newConst

is the given output constant

References code(), Varnode::copySymbolIfValid(), CPUI_COPY, CPUI_INT_2COMP, CPUI_INT_ADD, CPUI_INT_AND, CPUI_INT_LEFT, CPUI_INT_MULT, CPUI_INT_NEGATE, CPUI_INT_OR, CPUI_INT_RIGHT, CPUI_INT_SRIGHT, CPUI_INT_XOR, CPUI_INT_ZEXT, CPUI_SUBPIECE, getIn(), Varnode::getOffset(), and Varnode::getSymbolEntry().

Referenced by RuleCollapseConstants::applyOp().

int4 PcodeOp::compareOrder

(

const PcodeOp *

bop

)

const

Compare the control-flow order of this and bop.

Compare the execution order of -this- and -bop-, if -this- executes earlier (dominates) return -1; if -bop- executes earlier return 1, otherwise return 0. Note that 0 is returned if there is no absolute execution order.

Parameters

bop	is the PcodeOp to compare this to

Returns

-1, 0, or 1, depending on the comparison

References FlowBlock::findCommonBlock(), SeqNum::getOrder(), parent, and start.

Referenced by RuleOrPredicate::applyOp().

list<PcodeOp *>::iterator PcodeOp::getBasicIter ( void  ) const

inline

Get position within basic block

Referenced by RuleDoubleIn::applyOp(), Heritage::concatPieces(), FuncCallSpecs::insertPcode(), Funcdata::opInsertAfter(), Funcdata::opInsertBefore(), Heritage::removeRevisitedMarkers(), ActionStackPtrFlow::repair(), and Heritage::splitPieces().

uintm PcodeOp::getCseHash

(

void

)

const

Return hash indicating possibility of common subexpression elimination.

Produce a hash of the following attributes: output size, the opcode, and the identity of each input varnode. This is suitable for determining if two PcodeOps calculate identical values

Returns

the calculated hash or 0 if the op is not cse hashable

References binary, code(), CPUI_COPY, Varnode::getCreateIndex(), getEvalType(), getIn(), Varnode::getOffset(), Varnode::getSize(), inrefs, Varnode::isConstant(), output, and unary.

Referenced by RuleSelectCse::applyOp().

uintb PcodeOp::getNZMaskLocal

(

bool

cliploop

)

const

Calculate known zero bits for output to this op.

Compute nonzeromask assuming inputs to op have their masks properly defined. Assume the op has an output. For any inputs to this op, that have zero bits where their nzmasks have zero bits, then the output produced by this op is guaranteed to have zero bits at every location in the nzmask calculated by this function.

Parameters

cliploop

indicates the calculation shouldn't include inputs from known looping edges

Returns

the calculated non-zero mask

References calc_mask(), coveringmask(), CPUI_BOOL_AND, CPUI_BOOL_NEGATE, CPUI_BOOL_OR, CPUI_BOOL_XOR, CPUI_CALL, CPUI_CALLIND, CPUI_COPY, CPUI_CPOOLREF, CPUI_FLOAT_EQUAL, CPUI_FLOAT_LESS, CPUI_FLOAT_LESSEQUAL, CPUI_FLOAT_NAN, CPUI_FLOAT_NOTEQUAL, CPUI_INT_ADD, CPUI_INT_AND, CPUI_INT_CARRY, CPUI_INT_DIV, CPUI_INT_EQUAL, CPUI_INT_LEFT, CPUI_INT_LESS, CPUI_INT_LESSEQUAL, CPUI_INT_MULT, CPUI_INT_NOTEQUAL, CPUI_INT_OR, CPUI_INT_REM, CPUI_INT_RIGHT, CPUI_INT_SBORROW, CPUI_INT_SCARRY, CPUI_INT_SEXT, CPUI_INT_SLESS, CPUI_INT_SLESSEQUAL, CPUI_INT_SRIGHT, CPUI_INT_XOR, CPUI_INT_ZEXT, CPUI_MULTIEQUAL, CPUI_PIECE, CPUI_POPCOUNT, CPUI_SUBPIECE, getIn(), Varnode::getNZMask(), Varnode::getOffset(), TypeOp::getOpcode(), Varnode::getSize(), inrefs, isCalculatedBool(), Varnode::isConstant(), FlowBlock::isLoopIn(), leastsigbit_set(), mostsigbit_set(), opcode, output, parent, pcode_left(), pcode_right(), popcount(), and sign_extend().

Referenced by Funcdata::calcNZMask().

int4 PcodeOp::getRepeatSlot	(	const Varnode *	vn,
		int4	firstSlot,
		list< PcodeOp * >::const_iterator	iter
	)		const

Find the slot for a given Varnode, which may be take up multiple input slots.

In the rare case that this PcodeOp takes the same Varnode as input multiple times, use the specific descendant iterator producing this PcodeOp to work out the corresponding slot. Every slot containing the given Varnode will be produced exactly once over the course of iteration.

Parameters

vn	is the given Varnode
firstSlot	is the first instance of the Varnode in this input list
iter	is the specific descendant iterator producing this

Returns

the slot corresponding to the iterator

References Varnode::beginDescend(), and inrefs.

Referenced by SubvariableFlow::traceForward(), SubfloatFlow::traceForward(), and SubvariableFlow::traceForwardSext().

void PcodeOp::insertInput ( int4  slot )

private

Make room for a new input Varnode at a specific position.

Insert space for a new Varnode before slot. The new space is filled with null.

Parameters

slot	is index of the slot where the new space is inserted

References inrefs.

Referenced by Funcdata::opInsertInput(), and Funcdata::spacebaseConstant().

bool PcodeOp::isBranch ( void  ) const

inline

Return true if this op is a branch

References branch, and call.

Referenced by PrintC::emitBlockBasic(), ConditionalExecution::execute(), BlockBasic::hasOnlyMarkers(), BlockBasic::insert(), Funcdata::nodeSplitCloneOp(), IopSpace::printRaw(), and Funcdata::spliceBlockBasic().

bool PcodeOp::isCall ( void  ) const

inline

Return true if this op indicates call semantics

References call, and has_callspec.

Referenced by ActionDeadCode::apply(), RuleEarlyRemoval::applyOp(), RuleIndirectCollapse::applyOp(), RulePiecePathology::applyOp(), ActionMarkExplicit::baseExplicit(), Funcdata::blockRemoveInternal(), ActionMarkImplied::checkImpliedCover(), ActionMarkExplicit::checkNewToConstructor(), ValueSetSolver::constraintsFromCBranch(), ValueSetSolver::constraintsFromPath(), functionalEqualityLevel(), BlockBasic::isComplex(), RulePiecePathology::isPathology(), JumpBasic::isprune(), CastStrategyC::localExtensionType(), Merge::mergeAdjacent(), ActionDeadCode::neverConsumed(), Funcdata::nodeSplitInputPatch(), Heritage::normalizeWriteSize(), ActionStackPtrFlow::repair(), ConditionalExecution::testRemovability(), SubvariableFlow::traceForward(), and SubvariableFlow::traceForwardSext().

bool PcodeOp::isCollapsible

(

void

)

const

Return true if this can be collapsed to a COPY of a constant

Can this be collapsed to a copy op, i.e. are all inputs constants

Returns

true if this op can be callapsed

References code(), CPUI_COPY, flags, getIn(), getOut(), Varnode::getSize(), inrefs, isAssignment(), Varnode::isConstant(), and nocollapse.

Referenced by RuleCollapseConstants::applyOp().

bool PcodeOp::isCseMatch

(

const PcodeOp *

op

)

const

Return true if this and op represent common subexpressions.

Do these two ops represent a common subexpression? This is the full test of matching indicated by getCseHash

Parameters

op	is the PcodeOp to compare with this

Returns

true if the two ops are a common subexpression match

References binary, code(), CPUI_COPY, getEvalType(), getIn(), Varnode::getOffset(), Varnode::getSize(), inrefs, Varnode::isConstant(), output, and unary.

Referenced by RuleTrivialArith::applyOp(), and cseEliminateList().

bool PcodeOp::isIncidentalCopy ( void  ) const

inline

Return true if this COPY is incidental

References booloutput, calculated_bool, and incidental_copy.

Referenced by Funcdata::ancestorOpUse(), and AncestorRealistic::enterNode().

bool PcodeOp::isIndirectStore ( void  ) const

inline

Return true if this INDIRECT is caused by STORE

References indirect_store, marker, nonprinting, and noreturn.

Referenced by ActionDirectWrite::apply(), Funcdata::checkIndirectUse(), AncestorRealistic::enterNode(), ValueSetSolver::establishValueSets(), Heritage::findAddressForces(), and ActionLikelyTrash::traceTrash().

PcodeOp * PcodeOp::previousOp

(

void

)

const

Return the previous op within this op's basic block or null.

Find the previous op that flowed uniquely into this op, if it exists. This routine will not search farther than the basic block containing this.

Returns

the previous PcodeOp or null

References basiciter, BlockBasic::beginOp(), and parent.

Referenced by ActionShadowVar::apply(), FuncCallSpecs::collectOutputTrialVarnodes(), Heritage::reprocessFreeStores(), and FuncCallSpecs::transferLockedOutputParam().

void PcodeOp::printDebug

(

ostream &

s

)

const

Print debug description of this op to stream.

Print an address and a raw representation of this op to the stream, suitable for console debugging apps

Parameters

s	is the stream to print to

References isDead(), parent, printRaw(), and start.

Referenced by PcodeEmitFd::dump().

void PcodeOp::removeInput ( int4  slot )

private

Eliminate a specific input Varnode.

Remove the input Varnode in a specific slot. The slot is eliminated and all Varnodes beyond this slot are renumbered. All the other Varnodes are otherwise undisturbed.

Parameters

slot	is the index of the Varnode to remove

References inrefs.

Referenced by Funcdata::opRemoveInput().

void PcodeOp::saveXml

(

ostream &

s

)

const

Write an XML description of this op to stream

Write a description including: the opcode name, the sequence number, and separate xml tags providing a reference number for each input and output Varnode

Parameters

s	is the stream to write to

References a_v_i(), a_v_u(), code(), CPUI_INDIRECT, CPUI_LOAD, CPUI_STORE, Varnode::getAddr(), Varnode::getCreateIndex(), getIn(), AddrSpace::getName(), getOpFromConst(), getSeqNum(), Varnode::getSpace(), Address::getSpaceFromConst(), SeqNum::getTime(), AddrSpace::getType(), inrefs, IPTR_CONSTANT, IPTR_IOP, output, SeqNum::saveXml(), and start.

Referenced by Funcdata::saveXmlTree().

void PcodeOp::setNumInputs ( int4  num )

private

Make sure this op has num inputs.

Make sure there are exactly num input slots for this op. All slots, regardless of the total being increased or decreased, are set to null.

Parameters

num	is the number of inputs to set

References inrefs.

Referenced by Funcdata::nodeSplitInputPatch(), and Funcdata::opSetAllInput().

void PcodeOp::setOpcode ( TypeOp *  t_op )

private

Set the opcode for this PcodeOp.

Set the behavioral class (opcode) of this operation. For most applications this should only be called by the PcodeOpBank. This is fairly low-level but does cache various boolean flags associated with the opcode

Parameters

t_op	is the behavioural class to set

References binary, booloutput, branch, call, coderef, commutative, flags, TypeOp::getFlags(), marker, nocollapse, opcode, returns, special, and unary.

Referenced by PcodeOpBank::changeOpcode().

PcodeOp * PcodeOp::target

(

void

)

const

Return starting op for instruction associated with this op.

Scan backward within the basic block containing this op and find the first op marked as the start of an instruction. This also works if basic blocks haven't been calculated yet, and all the ops are still in the dead list. The starting op may be from a different instruction if this op was from an instruction in a delay slot

Returns

the starting PcodeOp

References basiciter, flags, insertiter, isDead(), and startmark.

Referenced by PcodeOpBank::target().

---

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

• op.hh
• op.cc