Description of a control-flow block containing PcodeOps. More...

#include <block.hh>

Inheritance diagram for FlowBlock:

[legend]

Public Types
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...

Public Member Functions
	FlowBlock (void)
	Construct a block with no edges.

virtual void	markLabelBumpUp (bool bump)
	Let hierarchical blocks steal labels of their (first) components. More...

virtual void	printHeader (ostream &s) const
	Print a simple description of this to stream. More...

virtual void	printTree (ostream &s, int4 level) const
	Print tree structure of any blocks owned by this. More...

virtual void	emit (PrintLanguage *lng) const
	Emit the instructions in this FlowBlock as structured code. More...

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 FlowBlock *	nextFlowAfter (const FlowBlock *bl) const
	Get the leaf FlowBlock that will execute after the given FlowBlock. More...

virtual void	saveXmlHeader (ostream &s) const
	Save basic information as XML attributes. More...

virtual void	restoreXmlHeader (const Element *el)
	Restore basic information for XML attributes. More...

virtual void	restoreXmlBody (List::const_iterator &iter, List::const_iterator enditer, BlockMap &resolver)
	Restore details about this FlowBlock from an XML stream. More...

void	saveXmlEdges (ostream &s) const
	Save edge information to an XML stream. More...

void	restoreXmlEdges (List::const_iterator &iter, List::const_iterator enditer, BlockMap &resolver)
	Restore edges from an XML stream. More...

void	saveXml (ostream &s) const
	Write out this to an XML stream. More...

void	restoreXml (const Element *el, BlockMap &resolver)
	Restore this from an XML stream. More...

const FlowBlock *	nextInFlow (void) const
	Return next block to be executed in flow. More...

void	setGotoBranch (int4 i)
	Mark a goto branch. More...

bool	isJumpTarget (void) const
	Return true if non-fallthru jump flows into this. More...

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...

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...

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	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.

JumpTable *	getJumptable (void) const
	Get the JumpTable associated this block. More...

Static Public Member Functions
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...

Friends
class	BlockGraph

Detailed Description

Description of a control-flow block containing PcodeOps.

This is the base class for basic blocks (BlockBasic) and the hierarchical description of structured code. At all levels, these can be viewed as a block of code (PcodeOp objects) with other blocks flowing into and out of it.

Member Enumeration Documentation

◆ block_flags

enum FlowBlock::block_flags

Boolean properties of blocks.

The first four flags describe attributes of the blocks primary exiting edges The f_interior_* flags do not necessarily apply to these edges. They are used with the block structure and hierarchy algorithms where unstructured jumps are removed from the list of primary edges. These flags keep track only of the existence of unstructured edges, even though they aren't listed

Enumerator
f_goto_goto	(Block ends in) non-structured branch
f_break_goto	Block ends with a break;.
f_continue_goto	Block ends with a continue;.
f_switch_out	Output is decided by switch.
f_unstructured_targ	Block is destination of unstructured goto.
f_mark	Generic way to mark a block.
f_mark2	A secondary mark.
f_entry_point	Official entry point of the function.
f_interior_gotoout	The block has an unstructured jump out of interior.
f_interior_gotoin	Block is target of unstructured jump to its interior.
f_label_bumpup	Any label printed higher up in hierarchy.
f_donothing_loop	Block does nothing in infinite loop (halt)
f_dead	Block is in process of being deleted.
f_whiledo_overflow	Set if the conditional block of a whiledo is too big to print as while(cond) { ...
f_flip_path	If true, out edges have been flipped since last time path was traced.
f_joined_block	Block is a merged form of original basic blocks.
f_duplicate_block	Block is a duplicated version of an original basic block.

◆ edge_flags

enum FlowBlock::edge_flags

Boolean properties on edges.

Enumerator
f_goto_edge	Edge is unstructured.
f_loop_edge	Edge completes a loop, removing these edges gives you a DAG.
f_defaultswitch_edge	This is default edge from switchblock.
f_irreducible	Edge which must be removed to make graph reducible.
f_tree_edge	An edge in the spanning tree.
f_forward_edge	An edge that jumps forward in the spanning tree.
f_cross_edge	An edge that crosses subtrees in the spanning tree.
f_back_edge	Within (reducible) graph, a back edge defining a loop.
f_loop_exit_edge	Edge exits the body of a loop.

Member Function Documentation

◆ calcDepth()

int4 FlowBlock::calcDepth ( const FlowBlock * leaf ) const

Get the depth of the given component FlowBlock.

How many getParent() calls from the leaf to this

Parameters

leaf	is the component FlowBlock

Returns: the depth count

◆ compareBlockIndex()

bool FlowBlock::compareBlockIndex	(	const FlowBlock *	bl1,
		const FlowBlock *	bl2
	)

inlinestatic

Compare FlowBlock by index.

Parameters

bl1	is the first FlowBlock to compare
bl2	is the second FlowBlock to compare

Returns: true if the first comes before the second

◆ compareFinalOrder()

bool FlowBlock::compareFinalOrder	(	const FlowBlock *	bl1,
		const FlowBlock *	bl2
	)

static

Final FlowBlock comparison.

Comparator for ordering the final 0-exit blocks

Parameters

bl1	is the first FlowBlock to compare
bl2	is the second FlowBlock

Returns: true if the first comes before the second

◆ dominates()

bool FlowBlock::dominates ( const FlowBlock * subBlock ) const

Does this block dominate the given block.

Return true if this block dominates the given block (or is equal to it). This assumes that block indices have been set with a reverse post order so that having a smaller index is a necessary condition for dominance.

Parameters

subBlock is the given block to test against this for dominance

Returns: true if this dominates

◆ emit()

void FlowBlock::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 in BlockSwitch, BlockInfLoop, BlockDoWhile, BlockWhileDo, BlockIf, BlockCondition, BlockList, BlockMultiGoto, BlockGoto, BlockCopy, BlockBasic, and BlockGraph.

◆ findCommonBlock() [1/2]

FlowBlock * FlowBlock::findCommonBlock ( const vector< FlowBlock * > & blockSet )

static

Find common dominator of multiple FlowBlocks.

Find the most immediate dominating FlowBlock of all blocks in the given set. The container must not be empty.

Parameters

blockSet is the given set of blocks

Returns: the most immediate dominating FlowBlock

◆ findCommonBlock() [2/2]

FlowBlock * FlowBlock::findCommonBlock	(	FlowBlock *	bl1,
		FlowBlock *	bl2
	)

static

Find the common dominator of two FlowBlocks.

Within the dominator tree, find the earliest common ancestor of two FlowBlocks

Parameters

bl1	is the first FlowBlock
bl2	is the second

Returns: the common ancestor which dominates both

◆ flipInPlaceExecute()

void FlowBlock::flipInPlaceExecute ( void )

inlinevirtual

Perform the flip to normalize conditional branch executed by this block.

This reverses the outgoing edge order in the right basic blocks, but does not modify the instructions directly.

Reimplemented in BlockCondition, and BlockBasic.

◆ flipInPlaceTest()

int4 FlowBlock::flipInPlaceTest ( vector< PcodeOp * > & fliplist ) const

inlinevirtual

Test normalizing the conditional branch in this.

Find the set of PcodeOp objects that need to be adjusted to flip the condition this FlowBlock calculates.

Return:

0 if the flip would normalize the condition
1 if the flip doesn't affect normalization of the condition
2 if the flip produces an unnormalized condition
Parameters

fliplist will contain the PcodeOps that need to be adjusted

Returns
0 if the condition will be normalized, 1 or 2 otherwise

Reimplemented in BlockCondition, and BlockBasic.

◆ getFrontLeaf() [1/2]

FlowBlock * FlowBlock::getFrontLeaf ( void )

Get the first leaf FlowBlock.

Keep descending tree hierarchy, taking the front block, until we get to the bottom copy block

Returns: the first leaf FlowBlock to execute

◆ getFrontLeaf() [2/2]

const FlowBlock * FlowBlock::getFrontLeaf ( void ) const

Get the first leaf FlowBlock.

Keep descending tree hierarchy, taking the front block, until we get to the bottom copy block

Returns: the first leaf FlowBlock to execute

◆ getInIndex()

int4 FlowBlock::getInIndex ( const FlowBlock * bl ) const

Get the incoming edge index for the given FlowBlock.

Search through incoming blocks in edge order for the given block.

Parameters

bl	is the given FlowBlock

Returns: the matching edge index or -1 if bl doesn't flow into this

◆ getJumptable()

JumpTable * FlowBlock::getJumptable ( void ) const

Get the JumpTable associated this block.

If this FlowBlock was ends with a computed jump, retrieve the associated JumpTable object

Returns: the JumpTable object or NULL

◆ getOutIndex()

int4 FlowBlock::getOutIndex ( const FlowBlock * bl ) const

Get the outgoing edge index for the given FlowBlock.

Search through outgoing blocks in edge order for the given block.

Parameters

bl	is the given FlowBlock

Returns: the matching edge index or -1 if bl doesn't flow out of this

◆ getSplitPoint()

FlowBlock * FlowBlock::getSplitPoint ( void )

inlinevirtual

Get the leaf splitting block.

If this block ends with a conditional branch, return the deepest component block that performs the split. This component needs to be able to perform flipInPlaceTest() and flipInPlaceExecute()

Returns: the component FlowBlock or NULL if this doesn't end in a conditional branch

Reimplemented in BlockCondition, BlockList, BlockCopy, and BlockBasic.

◆ hasLoopIn()

bool FlowBlock::hasLoopIn ( void ) const

Is there a looping edge coming into this block.

Returns: true if this is the top of a loop

◆ hasLoopOut()

bool FlowBlock::hasLoopOut ( void ) const

Is there a looping edge going out of this block.

Returns: true if this is the bottom of a loop

◆ isJumpTarget()

bool FlowBlock::isJumpTarget ( void ) const

Return true if non-fallthru jump flows into this.

return true if block is the target of a jump

◆ markLabelBumpUp()

void FlowBlock::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 in BlockInfLoop, BlockDoWhile, BlockWhileDo, and BlockGraph.

◆ nameToType()

FlowBlock::block_type FlowBlock::nameToType ( const string & nm )

static

Get the block_type associated with a name string.

Given a string describing a FlowBlock type, return the block_type. This is currently only used by the restoreXml() process. TODO: Fill in the remaining names and types

Parameters

nm	is the name string

Returns: the corresponding block_type

◆ negateCondition()

bool FlowBlock::negateCondition ( bool toporbottom )

virtual

Flip the condition computed by this.

Flip the order of outgoing edges (at least). This should also affect the original op causing the condition. Note: we don't have to flip at all levels of the hierarchy only at the top and at the bottom

Parameters

toporbottom is true if this is the top outermost block of the hierarchy getting negated

Returns: true if a change was made to data-flow

Reimplemented in BlockCondition, BlockList, BlockCopy, and BlockBasic.

◆ nextFlowAfter()

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

inlinevirtual

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 in BlockSwitch, BlockInfLoop, BlockDoWhile, BlockWhileDo, BlockIf, BlockCondition, BlockMultiGoto, BlockGoto, and BlockGraph.

◆ nextInFlow()

const FlowBlock * FlowBlock::nextInFlow ( void ) const

Return next block to be executed in flow.

If there are two branches, pick the fall-thru branch

Returns: the next block in flow, or NULL otherwise

◆ preferComplement()

bool FlowBlock::preferComplement ( Funcdata & data )

inlinevirtual

Rearrange this hierarchy to simplify boolean expressions.

For the instructions in this block, decide if the control-flow structure can be rearranged so that boolean expressions come out more naturally.

Parameters

data	is the function to analyze

Returns: true if a change was made

Reimplemented in BlockIf.

◆ printHeader()

void FlowBlock::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 in BlockSwitch, BlockInfLoop, BlockDoWhile, BlockWhileDo, BlockIf, BlockCondition, BlockList, BlockMultiGoto, BlockGoto, BlockCopy, and BlockBasic.

◆ printTree()

void FlowBlock::printTree	(	ostream &	s,
		int4	level
	)		const

virtual

Print tree structure of any blocks owned by this.

Recursively print out the hierarchical structure of this FlowBlock.

Parameters

s	is the output stream
level	is the current level of indentation

Reimplemented in BlockCopy, and BlockGraph.

◆ restoreXml()

void FlowBlock::restoreXml	(	const Element *	el,
		BlockMap &	resolver
	)

Restore this from an XML stream.

Recover this and all it sub-components from an XML <block> tag.

This will construct all the sub-components using resolver as a factory.

Parameters

el	is the root XML element
resolver	acts as a factory and resolves cross-references

◆ restoreXmlBody()

virtual void FlowBlock::restoreXmlBody	(	List::const_iterator &	iter,
		List::const_iterator	enditer,
		BlockMap &	resolver
	)

inlinevirtual

Restore details about this FlowBlock from an XML stream.

Parameters

iter	is an iterator to XML elements containing component tags etc.
enditer	marks the end of the XML tags
resolver	is used to recover FlowBlock objects based on XML references

Reimplemented in BlockBasic, and BlockGraph.

◆ restoreXmlEdges()

void FlowBlock::restoreXmlEdges	(	List::const_iterator &	iter,
		List::const_iterator	enditer,
		BlockMap &	resolver
	)

Restore edges from an XML stream.

Parameters

iter	is an iterator to the <edge> tags
enditer	marks the end of the list of tags
resolver	is used to recover FlowBlock cross-references

◆ restoreXmlHeader()

void FlowBlock::restoreXmlHeader ( const Element * el )

virtual

Restore basic information for XML attributes.

Parameters

el	is the XML element to pull attributes from

◆ restrictedByConditional()

bool FlowBlock::restrictedByConditional ( const FlowBlock * cond ) const

Check if the condition from the given block holds for this block.

We assume the given block has 2 out-edges and that this block is immediately reached by one of these two edges. Some condition holds when traversing the out-edge to this, and the complement of the condition holds for traversing the other out-edge. We verify that the condition holds for this entire block. More specifically, we check that that there is no path to this through the sibling edge, where the complement of the condition holds (unless we loop back through the conditional block).

Parameters

cond	is the conditional block with 2 out-edges

Returns: true if the condition holds for this block

◆ saveXml()

void FlowBlock::saveXml ( ostream & s ) const

Write out this to an XML stream.

Serialize this and all its sub-components as an XML <block> tag.

Parameters

s	is the output stream

◆ saveXmlEdges()

void FlowBlock::saveXmlEdges ( ostream & s ) const

Save edge information to an XML stream.

Write <edge> tags to stream

Parameters

s	is the output stream

◆ saveXmlHeader()

void FlowBlock::saveXmlHeader ( ostream & s ) const

virtual

Save basic information as XML attributes.

Parameters

s	is the output stream

Reimplemented in BlockCondition, and BlockCopy.

◆ setGotoBranch()

void FlowBlock::setGotoBranch ( int4 i )

Mark a goto branch.

This is the main entry point for marking a branch from one block to another as unstructured.

Parameters

i	is the index of the outgoing edge to mark

◆ typeToName()

string FlowBlock::typeToName ( FlowBlock::block_type bt )

static

Get the name string associated with a block_type.

For use in serializng FlowBlocks to XML.

Parameters

bt	is the block_type

Returns: the corresponding name string

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

block.hh
block.cc

Public Types

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ block_flags

◆ edge_flags

Member Function Documentation

◆ calcDepth()

◆ compareBlockIndex()

◆ compareFinalOrder()

◆ dominates()

◆ emit()

◆ findCommonBlock() [1/2]

◆ findCommonBlock() [2/2]

◆ flipInPlaceExecute()

◆ flipInPlaceTest()

◆ getFrontLeaf() [1/2]

◆ getFrontLeaf() [2/2]

◆ getInIndex()

◆ getJumptable()

◆ getOutIndex()

◆ getSplitPoint()

◆ hasLoopIn()

◆ hasLoopOut()

◆ isJumpTarget()

◆ markLabelBumpUp()

◆ nameToType()

◆ negateCondition()

◆ nextFlowAfter()

◆ nextInFlow()

◆ preferComplement()

◆ printHeader()

◆ printTree()

◆ restoreXml()

◆ restoreXmlBody()

◆ restoreXmlEdges()

◆ restoreXmlHeader()

◆ restrictedByConditional()

◆ saveXml()

◆ saveXmlEdges()

◆ saveXmlHeader()

◆ setGotoBranch()

◆ typeToName()