org.jikesrvm.compilers.opt.regalloc

Class RegisterAllocatorState

java.lang.Object

org.jikesrvm.compilers.opt.regalloc.RegisterAllocatorState

public class RegisterAllocatorState
extends Object

The register allocator currently caches a bunch of state in the IR; This class provides accessors to this state.

• TODO: Consider caching the state in a lookaside structure.
• TODO: Currently, the physical registers are STATIC! fix this.

Field Summary

Fields

Modifier and Type	Field and Description
private Map<Instruction,Integer>	depthFirstNumbers
private CompoundInterval[]	intervals
private int[]	spills

Constructor Summary

Constructors

Constructor and Description
RegisterAllocatorState(int registerCount)

Method Summary

Modifier and Type	Method and Description
(package private) void	clearOneToOne(Register r) Clears any 1-to-1 mapping for a register.
int	getDFN(Instruction inst) returns the dfn associated with the passed instruction
(package private) int	getDfnBegin(LiveIntervalElement live, BasicBlock bb)
(package private) int	getDfnEnd(LiveIntervalElement live, BasicBlock bb)
(package private) CompoundInterval	getInterval(Register reg) Returns the interval associated with the passed register.
(package private) Register	getMapping(Register r)
int	getSpill(Register reg)
(package private) void	initializeDepthFirstNumbering(int instructionCount) Initializes data structures for depth first numbering.
(package private) void	mapOneToOne(Register A, Register B) Records that register A and register B are associated with each other in a bijection.
(package private) void	printDfns(IR ir) Prints the DFN numbers associated with each instruction.
(package private) void	resetPhysicalRegisters(IR ir) Resets the physical register info.
(package private) void	setDFN(Instruction inst, int dfn) Associates the passed dfn number with the instruction
(package private) void	setInterval(Register reg, CompoundInterval interval) Associates the passed live interval with the passed register.
(package private) void	setSpill(Register reg, int spill)

Methods inherited from class java.lang.Object

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

Field Detail

spills

private final int[] spills

intervals

private final CompoundInterval[] intervals

depthFirstNumbers

private Map<Instruction,Integer> depthFirstNumbers

Constructor Detail

RegisterAllocatorState

RegisterAllocatorState(int registerCount)

Method Detail

resetPhysicalRegisters

void resetPhysicalRegisters(IR ir)

Resets the physical register info.

Parameters:

ir - the IR whose info is to be reset

setSpill

void setSpill(Register reg,
              int spill)

getSpill

public int getSpill(Register reg)

mapOneToOne

void mapOneToOne(Register A,
                 Register B)

Records that register A and register B are associated with each other in a bijection.

The register allocator uses this state to indicate that a symbolic register is presently allocated to a physical register.

Parameters:

A - first register

B - second register

getMapping

Register getMapping(Register r)

Parameters:

r - a register

Returns:

the register currently mapped 1-to-1 to r

clearOneToOne

void clearOneToOne(Register r)

Clears any 1-to-1 mapping for a register.

Parameters:

r - the register whose mapping is to be cleared

getInterval

CompoundInterval getInterval(Register reg)

Returns the interval associated with the passed register.

Parameters:

reg - the register

Returns:

the live interval or null

initializeDepthFirstNumbering

void initializeDepthFirstNumbering(int instructionCount)

Initializes data structures for depth first numbering.

Parameters:

instructionCount - an estimate of the total number of instructions.

setInterval

void setInterval(Register reg,
                 CompoundInterval interval)

Associates the passed live interval with the passed register.

Parameters:

reg - the register

interval - the live interval

setDFN

void setDFN(Instruction inst,
            int dfn)

Associates the passed dfn number with the instruction

Parameters:

inst - the instruction

dfn - the dfn number

getDFN

public int getDFN(Instruction inst)

returns the dfn associated with the passed instruction

Parameters:

inst - the instruction

Returns:

the associated dfn

printDfns

void printDfns(IR ir)

Prints the DFN numbers associated with each instruction.

Parameters:

ir - the IR that contains the instructions

getDfnBegin

int getDfnBegin(LiveIntervalElement live,
                BasicBlock bb)

Parameters:

live - the live interval

bb - the basic block for the live interval

Returns:

the Depth-first-number of the beginning of the live interval. If the interval is open-ended, the dfn for the beginning of the basic block will be returned instead.

getDfnEnd

int getDfnEnd(LiveIntervalElement live,
              BasicBlock bb)

Parameters:

live - the live interval

bb - the basic block for the live interval

Returns:

the Depth-first-number of the end of the live interval. If the interval is open-ended, the dfn for the end of the basic block will be returned instead.