#include <Trace.hpp>

Inheritance diagram for jlm::rvsdg::OutputTracer:

Public Member Functions
virtual	~OutputTracer ()

	OutputTracer (bool enableCaching) noexcept

bool	isTracingThroughStructuralNodes () const noexcept

void	setTraceThroughStructuralNodes (bool value) noexcept

bool	isEnteringPhiNodes () const noexcept

void	setEnterPhiNodes (bool value) noexcept

bool	isInterprocedural () const noexcept

void	setInterprocedural (bool value) noexcept

Output &	trace (Output &output)

Output &	trace (Output &output, const rvsdg::Region *withinRegion)

Output *	tryTraceThroughGamma (GammaNode &gammaNode, Output &output)

Output *	tryTraceThroughTheta (ThetaNode &thetaNode, Output &output)

void	clearCache ()

Protected Member Functions
virtual Output &	traceStep (Output &output, const rvsdg::Region *withinRegion)

Output *	insertInCache (const Output &output, Input *traceResult)

std::optional< Output * >	lookupInCache (const Output &output)

Protected Attributes
bool	traceThroughStrucutalNodes_ = true

bool	enterPhiNodes_ = true

bool	isInterprocedural_ = true

bool	enableCaching_

std::unordered_map< const Output , Input >	traceCache_ {}

Detailed Description

Helper class for tracing through RVSDG graphs to find the origins of outputs. Traces through simple nodes that do not affect the value, through structural nodes when the value is invariant, and out of structural nodes when the value is passed in.

It supports caching of traced values at gamma and theta outputs to avoid the retracing of a value through these structural nodes.

Definition at line 27 of file Trace.hpp.

Constructor & Destructor Documentation

◆ ~OutputTracer()

jlm::rvsdg::OutputTracer::~OutputTracer ( )

virtualdefault

◆ OutputTracer()

jlm::rvsdg::OutputTracer::OutputTracer ( bool enableCaching )

explicitnoexcept

Creates an OutputTracer with the default configuration

Parameters

enableCaching Determines whether the output tracer should cache traced results.

Definition at line 17 of file Trace.cpp.

Member Function Documentation

◆ clearCache()

void jlm::rvsdg::OutputTracer::clearCache ( )

inline

Clears the tracing cache.

Definition at line 162 of file Trace.hpp.

◆ insertInCache()

Output * jlm::rvsdg::OutputTracer::insertInCache	(	const Output &	output,
		Input *	traceResult
	)

protected

Inserts a traced value into the tracing cache.

Parameters

output	The output that was traced.
traceResult	The input at which the tracing arrived.

Returns: The origin of traceResult for convenience.

Definition at line 258 of file Trace.cpp.

◆ isEnteringPhiNodes()

bool jlm::rvsdg::OutputTracer::isEnteringPhiNodes ( ) const

inlinenoexcept

Controls if tracing is allowed to enter the subregion of a phi node from its outputs. If true, tracing can go further and reach lambda or delta nodes inside of phi nodes. It does, however, mean that the result of tracing can end up inside a region that is not an ancestor of the starting region in the region tree.

Returns: true if tracing may enter phi nodes.

Definition at line 72 of file Trace.hpp.

◆ isInterprocedural()

bool jlm::rvsdg::OutputTracer::isInterprocedural ( ) const

inlinenoexcept

Controls if tracing is allowed to leave functions. If true, outputs can be traced out of functions via context arguments. If false, tracing stops if it reaches lambda context arguments.

Returns: true if interprocedural tracing is enabled.

Definition at line 95 of file Trace.hpp.

◆ isTracingThroughStructuralNodes()

bool jlm::rvsdg::OutputTracer::isTracingThroughStructuralNodes ( ) const

inlinenoexcept

When tracing reaches the output of a structural node, how much effort should be made to check if the output is an invariant copy of one of the node's inputs. If true, tracing is performed inside the subregion(s) of the node. If false, only a simple invariant check is performed, which only detects invariance if the region result is directly connected to a region argument.

Returns: true if tracing though the subregions of structural nodes is enabled.

Definition at line 48 of file Trace.hpp.

◆ lookupInCache()

std::optional< Output * > jlm::rvsdg::OutputTracer::lookupInCache ( const Output & output )

protected

Loops up the tracing result for output.

Parameters

output The output that is traced.

Returns: The output at which tracing arrived, otherwise std::nullopt.

Definition at line 269 of file Trace.cpp.

◆ setEnterPhiNodes()

void jlm::rvsdg::OutputTracer::setEnterPhiNodes ( bool value )

inlinenoexcept

Enables or disables tracing into phi nodes from the outside.

See also: isEnteringPhiNodes()

Parameters

value the new value

Definition at line 83 of file Trace.hpp.

◆ setInterprocedural()

void jlm::rvsdg::OutputTracer::setInterprocedural ( bool value )

inlinenoexcept

Enables or disables interprocedural tracing.

See also: isInterprocedural()

Parameters

value the new value

Definition at line 106 of file Trace.hpp.

◆ setTraceThroughStructuralNodes()

void jlm::rvsdg::OutputTracer::setTraceThroughStructuralNodes ( bool value )

inlinenoexcept

Enables or disables tracing through the subregions of structural nodes.

See also: isTracingThroughStructuralNodes

Parameters

value the new value

Definition at line 59 of file Trace.hpp.

◆ trace() [1/2]

Output & jlm::rvsdg::OutputTracer::trace ( Output & output )

Traces from the given output to find the source of the output's value.

Parameters

output the output to trace from.

Definition at line 22 of file Trace.cpp.

◆ trace() [2/2]

Output & jlm::rvsdg::OutputTracer::trace	(	Output &	output,
		const rvsdg::Region *	withinRegion
	)

Traces from the given output to find the source of the output's value. The optional parameter withinRegion prevents values from being traced out of the region. If withinRegion is a nullptr, the tracing will continue until the output no longer changes.

Parameters

output	the output to trace from.
withinRegion	the region where we stop tracing.

Definition at line 28 of file Trace.cpp.

◆ traceStep()

Output & jlm::rvsdg::OutputTracer::traceStep	(	Output &	output,
		const rvsdg::Region *	withinRegion
	)

protectedvirtual

The innermost body of the tracing loop. Should trace at least one step, if possible. If it is not possible to trace further, the same output is returned.

Parameters

output	the output to trace from.
withinRegion	if not nullptr, tracing stops if it reaches an argument of the region.

Returns: the result of tracing from the given output, if possible. Otherwise, output.

Reimplemented in jlm::llvm::OutputTracer.

Definition at line 145 of file Trace.cpp.

◆ tryTraceThroughGamma()

Output * jlm::rvsdg::OutputTracer::tryTraceThroughGamma	(	GammaNode &	gammaNode,
		Output &	output
	)

Attempts to trace the output of a gamma node through the node. This is only possible if the output can be traced to a gamma entry variable in all subregions, and these entry variables all share the same origin outside the gamma.

Precondition: the output is an output of the given gammaNode

Parameters

gammaNode	the gamma node to trace through
output	an output of the given gamma node

Returns: the origin of the output value on the input side of the gamma, or nullptr.

Definition at line 57 of file Trace.cpp.

◆ tryTraceThroughTheta()

Output * jlm::rvsdg::OutputTracer::tryTraceThroughTheta	(	ThetaNode &	thetaNode,
		Output &	output
	)

Attempts to trace the the given loop output through the theta node, resulting in the origin of one of the theta node's inputs if successful. This is only possible if the output belongs to an invariant loop variable, or if the loop variable's post result takes its value from another invariant loop variable.

Precondition: the output is an output of the given thetaNode

Parameters

thetaNode	the theta node to trace through
output	an output of the given theta node

Returns: the origin of the output value on the input side of the theta, or nullptr.

Definition at line 106 of file Trace.cpp.

Member Data Documentation

◆ enableCaching_

bool jlm::rvsdg::OutputTracer::enableCaching_

protected

Definition at line 210 of file Trace.hpp.

◆ enterPhiNodes_

bool jlm::rvsdg::OutputTracer::enterPhiNodes_ = true

protected

Definition at line 203 of file Trace.hpp.

◆ isInterprocedural_

bool jlm::rvsdg::OutputTracer::isInterprocedural_ = true

protected

Definition at line 207 of file Trace.hpp.

◆ traceCache_

std::unordered_map<const Output *, Input *> jlm::rvsdg::OutputTracer::traceCache_ {}

protected

Definition at line 211 of file Trace.hpp.

◆ traceThroughStrucutalNodes_

bool jlm::rvsdg::OutputTracer::traceThroughStrucutalNodes_ = true

protected

Definition at line 199 of file Trace.hpp.

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

jlm/rvsdg/Trace.hpp
jlm/rvsdg/Trace.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ ~OutputTracer()

◆ OutputTracer()

Member Function Documentation

◆ clearCache()

◆ insertInCache()

◆ isEnteringPhiNodes()

◆ isInterprocedural()

◆ isTracingThroughStructuralNodes()

◆ lookupInCache()

◆ setEnterPhiNodes()

◆ setInterprocedural()

◆ setTraceThroughStructuralNodes()

◆ trace() [1/2]

◆ trace() [2/2]

◆ traceStep()

◆ tryTraceThroughGamma()

◆ tryTraceThroughTheta()

Member Data Documentation

◆ enableCaching_

◆ enterPhiNodes_

◆ isInterprocedural_

◆ traceCache_

◆ traceThroughStrucutalNodes_