org.jikesrvm.compilers.opt.ssa

Class PiNodes

java.lang.Object

org.jikesrvm.compilers.opt.driver.CompilerPhase

org.jikesrvm.compilers.opt.ssa.PiNodes

public final class PiNodes
extends CompilerPhase

This pass inserts PI nodes (Effectively copies) on branch edges, to introduce new names for analysis

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static boolean	CHECK_REF_PI Should we insert PI nodes for array references after bounds-checks and null-checks?
private static Constructor<CompilerPhase>	constructor Constructor for this compiler phase
(package private) boolean	insertion Should we insert (true) or delete (false) PI nodes?
(package private) boolean	typeChecks Are we adding pi nodes for type checks only?

Fields inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

container

Constructor Summary

Constructors

Constructor and Description
PiNodes(boolean insert) Create the phase.
PiNodes(boolean insert, boolean typeChecks) Create the phase.

Method Summary

Modifier and Type	Method and Description
(package private) static void	cleanUp(IR ir) Change all PI nodes to INT_MOVE instructions Side effect: invalidates SSA state
Constructor<CompilerPhase>	getClassConstructor() Get a constructor object for this compiler phase
static Instruction	getGenerator(Instruction def)
String	getName() A String representation of this phase
private void	insertPiBcNodes(IR ir) Insert Pi nodes for boundchecks.
private void	insertPiCheckCastNodes(IR ir) Insert Pi nodes for checkcast operations.
private void	insertPiIfNodes(IR ir) Insert PI nodes corresponding to compare operations.
private void	insertPiNullCheckNodes(IR ir) Insert Pi nodes for null check operations.
static boolean	isBoundsCheckPi(Instruction def)
static boolean	isNotTakenPi(Instruction def)
static boolean	isNullCheckPi(Instruction def)
static boolean	isTakenPi(Instruction def)
void	perform(IR ir) This is the method that actually does the work of the phase.
boolean	printingEnabled(OptOptions options, boolean before) Should we print the IR either before or after this phase?
boolean	shouldPerform(OptOptions options) Should this phase be performed?

Methods inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

dumpIR, dumpIR, getCompilerPhaseConstructor, getCompilerPhaseConstructor, newExecution, performPhase, reportAdditionalStats, setContainer, verify

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CHECK_REF_PI

static final boolean CHECK_REF_PI

Should we insert PI nodes for array references after bounds-checks and null-checks?

TODO: if this is false, then null-check elimination will be ineffective.

TODO: prove that null-check elimination is sound before turning this on again.

See Also:

Constant Field Values

insertion

final boolean insertion

Should we insert (true) or delete (false) PI nodes?

typeChecks

final boolean typeChecks

Are we adding pi nodes for type checks only? This is for GNOSYS analysis right now.

constructor

private static final Constructor<CompilerPhase> constructor

Constructor for this compiler phase

Constructor Detail

PiNodes

public PiNodes(boolean insert)

Create the phase.

Parameters:

insert - If true, we insert PI nodes, If false, we remove them.

PiNodes

public PiNodes(boolean insert,
               boolean typeChecks)

Create the phase.

Parameters:

insert - If true, we insert PI nodes, If false, we remove them.

typeChecks - If true, we insert PI nodes only for type checks.

Method Detail

shouldPerform

public boolean shouldPerform(OptOptions options)

Should this phase be performed? Only perform this when we are doing an SSA-based optimization that can benefit from PI nodes.

Overrides:

shouldPerform in class CompilerPhase

Parameters:

options - the compiler options for the compilation

Returns:

true if the phase should be performed

getClassConstructor

public Constructor<CompilerPhase> getClassConstructor()

Get a constructor object for this compiler phase

Overrides:

getClassConstructor in class CompilerPhase

Returns:

compiler phase constructor

getName

public String getName()

A String representation of this phase

Specified by:

getName in class CompilerPhase

Returns:

a string representation

printingEnabled

public boolean printingEnabled(OptOptions options,
                               boolean before)

Should we print the IR either before or after this phase?

Overrides:

printingEnabled in class CompilerPhase

Parameters:

options - controlling compiler options

before - control for the query

Returns:

true if the IR should be printed, false otherwise.

perform

public void perform(IR ir)

Description copied from class: CompilerPhase

This is the method that actually does the work of the phase.

Specified by:

perform in class CompilerPhase

Parameters:

ir - the IR on which to apply the phase

insertPiIfNodes

private void insertPiIfNodes(IR ir)

Insert PI nodes corresponding to compare operations. Pi-nodes are represented as dummy assignments with a single argument inserted along each outedge of the conditional.

Parameters:

ir - the governing IR

insertPiBcNodes

private void insertPiBcNodes(IR ir)

Insert Pi nodes for boundchecks.

Each boundcheck Arr, Index will be followed by

 PI Index, Index 

Parameters:

ir - the governing IR

insertPiNullCheckNodes

private void insertPiNullCheckNodes(IR ir)

Insert Pi nodes for null check operations.

Each checkcast obj will be followed by

 PI obj, obj 

Parameters:

ir - the governing IR

insertPiCheckCastNodes

private void insertPiCheckCastNodes(IR ir)

Insert Pi nodes for checkcast operations.

Each checkcast obj will be followed by

 ref_move obj, obj 

Parameters:

ir - the governing IR

cleanUp

static void cleanUp(IR ir)

Change all PI nodes to INT_MOVE instructions

Side effect: invalidates SSA state

Parameters:

ir - the governing IR

getGenerator

public static Instruction getGenerator(Instruction def)

isNotTakenPi

public static boolean isNotTakenPi(Instruction def)

isTakenPi

public static boolean isTakenPi(Instruction def)

isBoundsCheckPi

public static boolean isBoundsCheckPi(Instruction def)

isNullCheckPi

public static boolean isNullCheckPi(Instruction def)