org.graalvm.compiler.core.common.alloc

Class DefaultCodeEmissionOrder<T extends AbstractBlockBase<T>>

java.lang.Object

org.graalvm.compiler.core.common.alloc.DefaultCodeEmissionOrder<T>

All Implemented Interfaces:

CodeEmissionOrder<T>

public class DefaultCodeEmissionOrder<T extends AbstractBlockBase<T>>
extends Object
implements CodeEmissionOrder<T>

Computes an ordering of the blocks that can be used by the machine code generator. The machine code generation order will start with the first block and produce a straight sequence always following the most likely successor. Then it will continue with the most likely path that was left out during this process. The process iteratively continues until all blocks are scheduled. Additionally, it is guaranteed that all blocks of a loop are scheduled before any block following the loop is scheduled. The machine code generator order includes reordering of loop headers such that the backward jump is a conditional jump if there is only one loop end block. Additionally, the target of loop backward jumps are always marked as aligned. Aligning the target of conditional jumps does not bring a measurable benefit and is therefore avoided to keep the code size small.

Nested Class Summary

Nested classes/interfaces inherited from interface org.graalvm.compiler.core.common.cfg.CodeEmissionOrder

CodeEmissionOrder.ComputationTime

Field Summary

Fields

Modifier and Type	Field and Description
protected int	originalBlockCount
protected T	startBlock

Constructor Summary

Constructors

Constructor and Description
DefaultCodeEmissionOrder(int originalBlockCount, T startBlock)

Method Summary

Modifier and Type	Method and Description
AbstractBlockBase<?>[]	computeCodeEmittingOrder(OptionValues options, CodeEmissionOrder.ComputationTime computationTime) Computes the block order used for code emission.
protected static <T extends AbstractBlockBase<T>> boolean	skipLoopHeader(AbstractBlockBase<T> block) Skip the loop header block if the loop consists of more than one block and it has only a single loop end block in the same loop (not a backedge from a nested loop).

Methods inherited from class java.lang.Object

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

Field Detail

originalBlockCount

protected int originalBlockCount

startBlock

protected T extends AbstractBlockBase<T> startBlock

Constructor Detail

DefaultCodeEmissionOrder

public DefaultCodeEmissionOrder(int originalBlockCount,
                                T startBlock)

Method Detail

computeCodeEmittingOrder

public AbstractBlockBase<?>[] computeCodeEmittingOrder(OptionValues options,
                                                       CodeEmissionOrder.ComputationTime computationTime)

Computes the block order used for code emission.

Specified by:

computeCodeEmittingOrder in interface CodeEmissionOrder<T extends AbstractBlockBase<T>>

Returns:

sorted list of blocks

skipLoopHeader

protected static <T extends AbstractBlockBase<T>> boolean skipLoopHeader(AbstractBlockBase<T> block)

Skip the loop header block if the loop consists of more than one block and it has only a single loop end block in the same loop (not a backedge from a nested loop).