ghidra::BlockWhileDo Class Reference

A loop structure where the condition is checked at the top. More...

#include <block.hh>

Inheritance diagram for ghidra::BlockWhileDo:

Public Member Functions
	BlockWhileDo (void)
	Constructor.
PcodeOp *	getInitializeOp (void) const
	Get root of initialize statement or null.
PcodeOp *	getIterateOp (void) const
	Get root of iterate statement or null.
bool	hasOverflowSyntax (void) const
	Does this require overflow syntax.
void	setOverflowSyntax (void)
	Set that this requires overflow syntax.
virtual block_type	getType (void) const
	Get the FlowBlock type of this.
virtual void	markLabelBumpUp (bool bump)
	Let hierarchical blocks steal labels of their (first) components. More...
virtual void	scopeBreak (int4 curexit, int4 curloopexit)
	Mark unstructured edges that should be breaks.
virtual void	printHeader (ostream &s) const
	Print a simple description of this to stream. More...
virtual void	emit (PrintLanguage *lng) const
	Emit the instructions in this FlowBlock as structured code. More...
virtual FlowBlock *	nextFlowAfter (const FlowBlock *bl) const
	Get the leaf FlowBlock that will execute after the given FlowBlock. More...
virtual void	finalTransform (Funcdata &data)
virtual void	finalizePrinting (Funcdata &data) const
Public Member Functions inherited from ghidra::BlockGraph
void	clear (void)
	Clear all component FlowBlock objects.
virtual	~BlockGraph (void)
	Destructor.
const vector< FlowBlock * > &	getList (void) const
	Get the list of component FlowBlock objects.
int4	getSize (void) const
	Get the number of components.
FlowBlock *	getBlock (int4 i) const
	Get the i-th component.
virtual FlowBlock *	subBlock (int4 i) const
	Get the i-th component block.
virtual void	markUnstructured (void)
	Mark target blocks of any unstructured edges.
virtual void	printTree (ostream &s, int4 level) const
	Print tree structure of any blocks owned by this. More...
virtual void	printRaw (ostream &s) const
	Print raw instructions contained in this FlowBlock.
virtual void	encodeBody (Encoder &encoder) const
	Encode detail about components to a stream.
virtual void	decodeBody (Decoder &decoder)
	Restore details about this FlowBlock from an element stream. More...
void	decode (Decoder &decoder)
	Decode this BlockGraph from a stream. More...
void	addEdge (FlowBlock *begin, FlowBlock *end)
	Add a directed edge between component FlowBlocks. More...
void	addLoopEdge (FlowBlock *begin, int4 outindex)
	Mark a given edge as a loop edge. More...
void	removeEdge (FlowBlock *begin, FlowBlock *end)
	Remove an edge between component FlowBlocks. More...
void	switchEdge (FlowBlock *in, FlowBlock *outbefore, FlowBlock *outafter)
	Move an edge from one out FlowBlock to another. More...
void	moveOutEdge (FlowBlock *blold, int4 slot, FlowBlock *blnew)
	Move indicated out edge to a new FlowBlock. More...
void	removeBlock (FlowBlock *bl)
	Remove a FlowBlock from this BlockGraph. More...
void	removeFromFlow (FlowBlock *bl)
	Remove given FlowBlock preserving flow in this. More...
void	removeFromFlowSplit (FlowBlock *bl, bool flipflow)
	Remove FlowBlock splitting flow between input and output edges. More...
void	spliceBlock (FlowBlock *bl)
	Splice given FlowBlock together with its output. More...
void	setStartBlock (FlowBlock *bl)
	Set the entry point FlowBlock for this graph. More...
FlowBlock *	getStartBlock (void) const
	Get the entry point FlowBlock. More...
FlowBlock *	newBlock (void)
	Build a new plain FlowBlock. More...
BlockBasic *	newBlockBasic (Funcdata *fd)
	Build a new BlockBasic. More...
BlockCopy *	newBlockCopy (FlowBlock *bl)
	Build a new BlockCopy. More...
BlockGoto *	newBlockGoto (FlowBlock *bl)
	Build a new BlockGoto. More...
BlockMultiGoto *	newBlockMultiGoto (FlowBlock *bl, int4 outedge)
	Build a new BlockMultiGoto. More...
BlockList *	newBlockList (const vector< FlowBlock *> &nodes)
	Build a new BlockList. More...
BlockCondition *	newBlockCondition (FlowBlock *b1, FlowBlock *b2)
	Build a new BlockCondition. More...
BlockIf *	newBlockIfGoto (FlowBlock *cond)
	Build a new BlockIfGoto. More...
BlockIf *	newBlockIf (FlowBlock *cond, FlowBlock *tc)
	Build a new BlockIf. More...
BlockIf *	newBlockIfElse (FlowBlock *cond, FlowBlock *tc, FlowBlock *fc)
	Build a new BlockIfElse. More...
BlockWhileDo *	newBlockWhileDo (FlowBlock *cond, FlowBlock *cl)
	Build a new BlockWhileDo. More...
BlockDoWhile *	newBlockDoWhile (FlowBlock *condcl)
	Build a new BlockDoWhile. More...
BlockInfLoop *	newBlockInfLoop (FlowBlock *body)
	Build a new BlockInfLoop. More...
BlockSwitch *	newBlockSwitch (const vector< FlowBlock *> &cs, bool hasExit)
	Build a new BlockSwitch. More...
void	orderBlocks (void)
void	buildCopy (const BlockGraph &graph)
	Build a copy of a BlockGraph. More...
void	clearVisitCount (void)
	Clear the visit count in all node FlowBlocks.
void	calcForwardDominator (const vector< FlowBlock *> &rootlist)
	Calculate forward dominators. More...
void	buildDomTree (vector< vector< FlowBlock *> > &child) const
	Build the dominator tree. More...
int4	buildDomDepth (vector< int4 > &depth) const
	Calculate dominator depths. More...
void	buildDomSubTree (vector< FlowBlock *> &res, FlowBlock *root) const
	Collect nodes from a dominator sub-tree. More...
void	calcLoop (void)
	Calculate loop edges. More...
void	collectReachable (vector< FlowBlock *> &res, FlowBlock *bl, bool un) const
	Collect reachable/unreachable FlowBlocks from a given start FlowBlock. More...
void	structureLoops (vector< FlowBlock *> &rootlist)
	Label loop edges. More...
Public Member Functions inherited from ghidra::FlowBlock
	FlowBlock (void)
	Construct a block with no edges.
virtual	~FlowBlock (void)
	Destructor.
int4	getIndex (void) const
	Get the index assigned to this block.
FlowBlock *	getParent (void)
	Get the parent FlowBlock of this.
FlowBlock *	getImmedDom (void) const
	Get the immediate dominator FlowBlock.
FlowBlock *	getCopyMap (void) const
	Get the mapped FlowBlock.
const FlowBlock *	getParent (void) const
	Get the parent FlowBlock of this.
uint4	getFlags (void) const
	Get the block_flags properties.
virtual Address	getStart (void) const
	Get the starting address of code in this FlowBlock.
virtual Address	getStop (void) const
	Get the ending address of code in this FlowBlock.
virtual const FlowBlock *	getExitLeaf (void) const
	Get the FlowBlock to which this block exits.
virtual PcodeOp *	lastOp (void) const
	Get the last PcodeOp executed by this FlowBlock.
virtual bool	negateCondition (bool toporbottom)
	Flip the condition computed by this. More...
virtual bool	preferComplement (Funcdata &data)
	Rearrange this hierarchy to simplify boolean expressions. More...
virtual FlowBlock *	getSplitPoint (void)
	Get the leaf splitting block. More...
virtual int4	flipInPlaceTest (vector< PcodeOp *> &fliplist) const
	Test normalizing the conditional branch in this. More...
virtual void	flipInPlaceExecute (void)
	Perform the flip to normalize conditional branch executed by this block. More...
virtual bool	isComplex (void) const
	Is this too complex to be a condition (BlockCondition)
virtual void	encodeHeader (Encoder &encoder) const
	Encode basic information as attributes. More...
virtual void	decodeHeader (Decoder &decoder)
	Decode basic information from element attributes. More...
void	encodeEdges (Encoder &encoder) const
	Encode edge information to a stream. More...
void	decodeEdges (Decoder &decoder, BlockMap &resolver)
	Restore edges from an encoded stream. More...
void	encode (Encoder &encoder) const
	Encode this to a stream. More...
void	decode (Decoder &decoder, BlockMap &resolver)
	Decode this from a stream. More...
const FlowBlock *	nextInFlow (void) const
	Return next block to be executed in flow. More...
void	setVisitCount (int4 i)
	Set the number of times this block has been visited.
int4	getVisitCount (void) const
	Get the count of visits.
void	setGotoBranch (int4 i)
	Mark a goto branch. More...
void	setDefaultSwitch (int4 pos)
	Mark an edge as the switch default. More...
bool	isMark (void) const
	Return true if this block has been marked.
void	setMark (void)
	Mark this block.
void	clearMark (void)
	Clear any mark on this block.
void	setDonothingLoop (void)
	Label this as a do nothing loop.
void	setDead (void)
	Label this as dead.
bool	hasSpecialLabel (void) const
	Return true if this uses a different label.
bool	isJoined (void) const
	Return true if this is a joined basic block.
bool	isDuplicated (void) const
	Return true if this is a duplicated block.
void	setLoopExit (int4 i)
	Label the edge exiting this as a loop.
void	clearLoopExit (int4 i)
	Clear the loop exit edge.
void	setBackEdge (int4 i)
	Label the back edge of a loop.
bool	getFlipPath (void) const
	Have out edges been flipped.
bool	isJumpTarget (void) const
	Return true if non-fallthru jump flows into this. More...
FlowBlock *	getFalseOut (void) const
	Get the false output FlowBlock.
FlowBlock *	getTrueOut (void) const
	Get the true output FlowBlock.
FlowBlock *	getOut (int4 i)
	Get the i-th output FlowBlock.
const FlowBlock *	getOut (int4 i) const
	Get i-th output FlowBlock.
int4	getOutRevIndex (int4 i) const
	Get the input index of the i-th output FlowBlock.
FlowBlock *	getIn (int4 i)
	Get the i-th input FlowBlock.
const FlowBlock *	getIn (int4 i) const
	Get the i-th input FlowBlock.
int4	getInRevIndex (int4 i) const
	Get the output index of the i-th input FlowBlock.
const FlowBlock *	getFrontLeaf (void) const
	Get the first leaf FlowBlock. More...
FlowBlock *	getFrontLeaf (void)
	Get the first leaf FlowBlock. More...
int4	calcDepth (const FlowBlock *leaf) const
	Get the depth of the given component FlowBlock. More...
bool	dominates (const FlowBlock *subBlock) const
	Does this block dominate the given block. More...
bool	restrictedByConditional (const FlowBlock *cond) const
	Check if the condition from the given block holds for this block. More...
int4	sizeOut (void) const
	Get the number of out edges.
int4	sizeIn (void) const
	Get the number of in edges.
bool	hasLoopIn (void) const
	Is there a looping edge coming into this block. More...
bool	hasLoopOut (void) const
	Is there a looping edge going out of this block. More...
bool	isLoopIn (int4 i) const
	Is the i-th incoming edge a loop edge.
bool	isLoopOut (int4 i) const
	Is the i-th outgoing edge a loop edge.
int4	getInIndex (const FlowBlock *bl) const
	Get the incoming edge index for the given FlowBlock. More...
int4	getOutIndex (const FlowBlock *bl) const
	Get the outgoing edge index for the given FlowBlock. More...
bool	isDefaultBranch (int4 i) const
	Is the i-th out edge the switch default edge.
bool	isLabelBumpUp (void) const
	Are labels for this printed by the parent.
bool	isUnstructuredTarget (void) const
	Is this the target of an unstructured goto.
bool	isInteriorGotoTarget (void) const
	Is there an unstructured goto to this block's interior.
bool	hasInteriorGoto (void) const
	Is there an unstructured goto out of this block's interior.
bool	isEntryPoint (void) const
	Is the entry point of the function.
bool	isSwitchOut (void) const
	Is this a switch block.
bool	isDonothingLoop (void) const
	Is this a do nothing block.
bool	isDead (void) const
	Is this block dead.
bool	isTreeEdgeIn (int4 i) const
	Is the i-th incoming edge part of the spanning tree.
bool	isBackEdgeIn (int4 i) const
	Is the i-th incoming edge a back edge.
bool	isBackEdgeOut (int4 i) const
	Is the i-th outgoing edge a back edge.
bool	isIrreducibleOut (int4 i) const
	Is the i-th outgoing edge an irreducible edge.
bool	isIrreducibleIn (int4 i) const
	Is the i-th incoming edge an irreducible edge.
bool	isDecisionOut (int4 i) const
	Can this and the i-th output be merged into a BlockIf or BlockList.
bool	isDecisionIn (int4 i) const
	Can this and the i-th input be merged into a BlockIf or BlockList.
bool	isLoopDAGOut (int4 i) const
	Is the i-th outgoing edge part of the DAG sub-graph.
bool	isLoopDAGIn (int4 i) const
	Is the i-th incoming edge part of the DAG sub-graph.
bool	isGotoIn (int4 i) const
	Is the i-th incoming edge unstructured.
bool	isGotoOut (int4 i) const
	Is the i-th outgoing edge unstructured.
JumpTable *	getJumptable (void) const
	Get the JumpTable associated this block. More...

Private Member Functions
void	findLoopVariable (PcodeOp *cbranch, BlockBasic *head, BlockBasic *tail, PcodeOp *lastOp)
	Find a loop variable. More...
PcodeOp *	findInitializer (BlockBasic *head, int4 slot) const
	Find the for-loop initializer op. More...
PcodeOp *	testTerminal (Funcdata &data, int4 slot) const
	Test that given statement is terminal and explicit. More...
bool	testIterateForm (void) const
	Return false if the iterate statement is of an unacceptable form. More...

Private Attributes
PcodeOp *	initializeOp
	Statement used as for loop initializer.
PcodeOp *	iterateOp
	Statement used as for loop iterator.
PcodeOp *	loopDef
	MULTIEQUAL merging loop variable.

Additional Inherited Members
Public Types inherited from ghidra::FlowBlock
enum	block_type {   t_plain, t_basic, t_graph, t_copy,   t_goto, t_multigoto, t_ls, t_condition,   t_if, t_whiledo, t_dowhile, t_switch,   t_infloop }
	The possible block types.
enum	block_flags {   f_goto_goto = 1, f_break_goto = 2, f_continue_goto = 4, f_switch_out = 0x10,   f_unstructured_targ = 0x20, f_mark = 0x80, f_mark2 = 0x100, f_entry_point = 0x200,   f_interior_gotoout = 0x400, f_interior_gotoin = 0x800, f_label_bumpup = 0x1000, f_donothing_loop = 0x2000,   f_dead = 0x4000, f_whiledo_overflow = 0x8000, f_flip_path = 0x10000, f_joined_block = 0x20000,   f_duplicate_block = 0x40000 }
	Boolean properties of blocks. More...
enum	edge_flags {   f_goto_edge = 1, f_loop_edge = 2, f_defaultswitch_edge = 4, f_irreducible = 8,   f_tree_edge = 0x10, f_forward_edge = 0x20, f_cross_edge = 0x40, f_back_edge = 0x80,   f_loop_exit_edge = 0x100 }
	Boolean properties on edges. More...
Static Public Member Functions inherited from ghidra::FlowBlock
static block_type	nameToType (const string &name)
	Get the block_type associated with a name string. More...
static string	typeToName (block_type bt)
	Get the name string associated with a block_type. More...
static bool	compareBlockIndex (const FlowBlock *bl1, const FlowBlock *bl2)
	Compare FlowBlock by index. More...
static bool	compareFinalOrder (const FlowBlock *bl1, const FlowBlock *bl2)
	Final FlowBlock comparison. More...
static FlowBlock *	findCommonBlock (FlowBlock *bl1, FlowBlock *bl2)
	Find the common dominator of two FlowBlocks. More...
static FlowBlock *	findCommonBlock (const vector< FlowBlock *> &blockSet)
	Find common dominator of multiple FlowBlocks. More...
Protected Member Functions inherited from ghidra::BlockGraph
void	swapBlocks (int4 i, int4 j)
	Swap the positions two component FlowBlocks. More...
Protected Member Functions inherited from ghidra::FlowBlock
void	setFlag (uint4 fl)
	Set a boolean property.
void	clearFlag (uint4 fl)
	Clear a boolean property.
Static Protected Member Functions inherited from ghidra::BlockGraph
static void	markCopyBlock (FlowBlock *bl, uint4 fl)
	Set properties on the first leaf FlowBlock. More...

Detailed Description

A loop structure where the condition is checked at the top.

This has exactly two components: one conditional block which evaluates when the loop terminates, and one body block. The conditional block has two outgoing edges, one to the body block and one to the exit block. The body block has one outgoing edge back to the conditional block. The BlockWhileDo instance has exactly one outgoing edge.

Overflow syntax refers to the situation where there is a proper BlockWhileDo structure but the conditional block is too long or complicated to emit as a single conditional expression. An alternate while(true) { } form is used instead.

If an iterator op is provided, the block will be printed using for loop syntax, for(i=0;i<10;++i) where an initializer statement and iterator statement are printed alongside the condition statement. Otherwise, while loop syntax is used while(i<10)

Member Function Documentation

emit()

virtual void ghidra::BlockWhileDo::emit ( PrintLanguage *  lng ) const

inlinevirtual

Emit the instructions in this FlowBlock as structured code.

This is the main entry point, at the control-flow level, for printing structured code.

Parameters

lng	is the PrintLanguage that provides details of the high-level language being printed

Reimplemented from ghidra::BlockGraph.

References ghidra::PrintLanguage::emitBlockWhileDo().

finalizePrinting()

void ghidra::BlockWhileDo::finalizePrinting ( Funcdata &  data ) const

virtual

Assume that finalTransform() has run and that all HighVariable merging has occurred. Do any final tests checking that the initialization and iteration statements are good. Extract initialization and iteration statements from their basic blocks.

Parameters

data	is the function containing the loop

Reimplemented from ghidra::BlockGraph.

References ghidra::BlockGraph::finalizePrinting(), and ghidra::Funcdata::opMarkNonPrinting().

finalTransform()

void ghidra::BlockWhileDo::finalTransform ( Funcdata &  data )

virtual

Determine if this block can be printed as a for loop, with an initializer statement extracted from the previous block, and an iterator statement extracted from the body.

Parameters

data	is the function containing this loop

Reimplemented from ghidra::BlockGraph.

References ghidra::Architecture::analyze_for_loops, ghidra::PcodeOp::code(), ghidra::CPUI_CBRANCH, ghidra::BlockGraph::finalTransform(), ghidra::Funcdata::getArch(), ghidra::FlowBlock::getOut(), ghidra::FlowBlock::getOutRevIndex(), ghidra::PcodeOp::getParent(), ghidra::BlockBasic::getType(), ghidra::PcodeOp::isBranch(), ghidra::Funcdata::opInsertAfter(), ghidra::Funcdata::opUninsert(), ghidra::PcodeOp::previousOp(), ghidra::FlowBlock::sizeOut(), and ghidra::FlowBlock::subBlock().

findInitializer()

PcodeOp * ghidra::BlockWhileDo::findInitializer ( BlockBasic *  head, int4  slot  ) const

private

Find the for-loop initializer op.

Given a control flow loop, try to find a putative initializer PcodeOp for the loop variable. The initializer must be read by read by loopDef and by in a block that flows only into the loop. If an initializer is found, then initializeOp is set and the lastOp (not including a branch) in the initializer block is returned. Otherwise null is returned.

Parameters

head	is the head block of the loop
slot	is the block input coming from the loop tail

Returns

the last PcodeOp in the initializer's block

References ghidra::Varnode::getDef(), ghidra::FlowBlock::getIn(), ghidra::PcodeOp::getParent(), ghidra::PcodeOp::isBranch(), ghidra::PcodeOp::isMarker(), ghidra::Varnode::isWritten(), ghidra::FlowBlock::lastOp(), ghidra::PcodeOp::previousOp(), ghidra::FlowBlock::sizeIn(), and ghidra::FlowBlock::sizeOut().

findLoopVariable()

void ghidra::BlockWhileDo::findLoopVariable ( PcodeOp *  cbranch, BlockBasic *  head, BlockBasic *  tail, PcodeOp *  lastOp  )

private

Find a loop variable.

Try to find a Varnode that represents the controlling loop variable for this loop. The Varnode must be:

• tested by the exit condition
• have a MULTIEQUAL in the head block
• have a modification coming in from the tail block
• the modification must be the last op or moveable to the last op

If the loop variable is found, this routine sets the iterateOp and the loopDef.

Parameters

cbranch	is the CBRANCH implementing the loop exit
head	is the head basic-block of the loop
tail	is the tail basic-block of the loop
lastOp	is the precomputed last PcodeOp of tail that isn't a BRANCH

References ghidra::PcodeOp::code(), ghidra::CPUI_MULTIEQUAL, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::FlowBlock::getOutRevIndex(), ghidra::PcodeOp::getParent(), ghidra::PcodeOp::isCall(), ghidra::PcodeOp::isMarker(), ghidra::PcodeOp::isMoveable(), ghidra::Varnode::isWritten(), ghidra::PcodeOp::numInput(), ghidra::PcodeOpNode::op, and ghidra::PcodeOpNode::slot.

markLabelBumpUp()

void ghidra::BlockWhileDo::markLabelBumpUp ( bool  bump )

virtual

Let hierarchical blocks steal labels of their (first) components.

Parameters

bump	if true, mark that labels for this block are printed by somebody higher in hierarchy

Reimplemented from ghidra::BlockGraph.

References ghidra::BlockGraph::markLabelBumpUp().

nextFlowAfter()

FlowBlock * ghidra::BlockWhileDo::nextFlowAfter ( const FlowBlock *  bl ) const

virtual

Get the leaf FlowBlock that will execute after the given FlowBlock.

Within the hierarchy of this FlowBlock, assume the given FlowBlock will fall-thru in its execution at some point. Return the first leaf block (BlockBasic or BlockCopy) that will execute after the given FlowBlock completes, assuming this is a unique block.

Parameters

bl	is the given FlowBlock

Returns

the next FlowBlock to execute or NULL

Reimplemented from ghidra::BlockGraph.

References ghidra::FlowBlock::getFrontLeaf().

printHeader()

void ghidra::BlockWhileDo::printHeader ( ostream &  s ) const

virtual

Print a simple description of this to stream.

Only print a header for this single block

Parameters

s	is the output stream

Reimplemented from ghidra::FlowBlock.

References ghidra::FlowBlock::printHeader().

testIterateForm()

bool ghidra::BlockWhileDo::testIterateForm ( void  ) const

private

Return false if the iterate statement is of an unacceptable form.

Make sure the loop variable is involved as input in the iterator statement.

Returns

true if the loop variable is an input to the iterator statement

References ghidra::Varnode::getDef(), ghidra::Varnode::getHigh(), ghidra::Varnode::isAnnotation(), ghidra::Varnode::isExplicit(), and ghidra::Varnode::isWritten().

testTerminal()

PcodeOp * ghidra::BlockWhileDo::testTerminal ( Funcdata &  data, int4  slot  ) const

private

Test that given statement is terminal and explicit.

For-loop initializer or iterator statements must be the final statement in their respective basic block. This method tests that iterateOp/initializeOp (specified by slot) is the root of or can be turned into the root of a terminal statement. The root output must be an explicit variable being read by the loopDef MULTIEQUAL at the top of the loop. If the root is not the last PcodeOp in the block, an attempt is made to move it. Return the root PcodeOp if all these conditions are met, otherwise return null.

Parameters

data	is the function containing the while loop
slot	is the slot read by loopDef from the output of the statement

Returns

an explicit statement or null

References ghidra::PcodeOp::code(), ghidra::CPUI_COPY, ghidra::Varnode::getDef(), ghidra::PcodeOp::getIn(), ghidra::FlowBlock::getIn(), ghidra::PcodeOp::getParent(), ghidra::FlowBlock::getParent(), ghidra::PcodeOp::isBranch(), ghidra::Varnode::isExplicit(), ghidra::Varnode::isWritten(), ghidra::BlockBasic::lastOp(), ghidra::Funcdata::moveRespectingCover(), ghidra::PcodeOp::notPrinted(), and ghidra::PcodeOp::previousOp().

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

• block.hh
• block.cc