org.jikesrvm.compilers.opt.regalloc

Class IntervalAnalysis

java.lang.Object

org.jikesrvm.compilers.opt.driver.CompilerPhase

org.jikesrvm.compilers.opt.regalloc.IntervalAnalysis

public final class IntervalAnalysis
extends CompilerPhase

phase to compute linear scan intervals.

Field Summary

Fields

Modifier and Type	Field and Description
private static Constructor<CompilerPhase>	constructor Constructor for this compiler phase
private IR	ir the governing ir
private BasicBlock	listOfBlocks a list of basic blocks in topological order
private static boolean	MUTATE_FMOV Mark FMOVs that end a live range?
private RegisterAllocatorState	regAllocState
private BasicBlock	reverseTopFirst a reverse topological list of basic blocks

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

container

Constructor Summary

Constructors

Constructor and Description
IntervalAnalysis()

Method Summary

Modifier and Type	Method and Description
(package private) void	assignDepthFirstNumbers(ControlFlowGraph cfg) this method processes all basic blocks, do the following to each block 1) add it to the begining of the "listOfBlocks" list 2) number the instructions 3) process the instructions that restrict physical register assignment
private void	createTopAndReverseList(ControlFlowGraph cfg) create topological list and a reverse topological list the results are on listOfBlocks and reverseTopFirst lists
Constructor<CompilerPhase>	getClassConstructor() Get a constructor object for this compiler phase
String	getName() a name for this phase.
private void	initializeRegisters() Initialize the interval for each register to null.
private boolean	mutateFMOVs(LiveIntervalElement live, Register register, int dfnbegin, int dfnend) Mutate FMOVs that end live ranges
void	perform(IR ir) compute live intervals for this ir the result is a sorted (by beginning point) set of compound intervals, stored in the private 'intervals' field.
boolean	printingEnabled(OptOptions options, boolean before) should we print the ir?
private CompoundInterval	processLiveInterval(LiveIntervalElement live, BasicBlock bb) for each live interval associated with this block we either add a new interval, or extend a previous interval if it is contiguous
boolean	shouldPerform(OptOptions options) should we perform this phase?

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

ir

private IR ir

the governing ir

regAllocState

private RegisterAllocatorState regAllocState

listOfBlocks

private BasicBlock listOfBlocks

a list of basic blocks in topological order

reverseTopFirst

private BasicBlock reverseTopFirst

a reverse topological list of basic blocks

MUTATE_FMOV

private static final boolean MUTATE_FMOV

Mark FMOVs that end a live range?

See Also:

Constant Field Values

constructor

private static final Constructor<CompilerPhase> constructor

Constructor for this compiler phase

Constructor Detail

IntervalAnalysis

public IntervalAnalysis()

Method Detail

getClassConstructor

public Constructor<CompilerPhase> getClassConstructor()

Get a constructor object for this compiler phase

Overrides:

getClassConstructor in class CompilerPhase

Returns:

compiler phase constructor

shouldPerform

public boolean shouldPerform(OptOptions options)

should we perform this phase? yes.

Overrides:

shouldPerform in class CompilerPhase

Parameters:

options - the compiler options for the compilation

Returns:

true if the phase should be performed

getName

public String getName()

a name for this phase.

Specified by:

getName in class CompilerPhase

Returns:

a String which is the name of the phase.

printingEnabled

public boolean printingEnabled(OptOptions options,
                               boolean before)

should we print the ir?

Overrides:

printingEnabled in class CompilerPhase

Parameters:

options - the compiler options for the compilation

before - true when invoked before perform, false otherwise.

Returns:

true if the IR should be printed, false otherwise.

perform

public void perform(IR ir)

compute live intervals for this ir the result is a sorted (by beginning point) set of compound intervals, stored in the private 'intervals' field.

Specified by:

perform in class CompilerPhase

Parameters:

ir - the ir

createTopAndReverseList

private void createTopAndReverseList(ControlFlowGraph cfg)

create topological list and a reverse topological list the results are on listOfBlocks and reverseTopFirst lists

Parameters:

cfg - the control flow graph

assignDepthFirstNumbers

void assignDepthFirstNumbers(ControlFlowGraph cfg)

this method processes all basic blocks, do the following to each block 1) add it to the begining of the "listOfBlocks" list 2) number the instructions 3) process the instructions that restrict physical register assignment

Parameters:

cfg - the control flow graph

initializeRegisters

private void initializeRegisters()

Initialize the interval for each register to null.

mutateFMOVs

private boolean mutateFMOVs(LiveIntervalElement live,
                            Register register,
                            int dfnbegin,
                            int dfnend)

Mutate FMOVs that end live ranges

Parameters:

live - The live interval for a basic block/reg pair

register - The register for this live interval

dfnbegin - The (adjusted) begin for this interval

dfnend - The (adjusted) end for this interval

Returns:

whether an actual change was necessary (as opposed to simple removal because the end was dead)

processLiveInterval

private CompoundInterval processLiveInterval(LiveIntervalElement live,
                                             BasicBlock bb)

for each live interval associated with this block we either add a new interval, or extend a previous interval if it is contiguous

Parameters:

live - the liveintervalelement for a basic block/reg pair

bb - the basic block

Returns:

the resulting CompoundInterval. null if the live interval is not relevant to register allocation.