com.oracle.truffle.sl.nodes.expression

Class SLAddNode

java.lang.Object

com.oracle.truffle.api.nodes.Node

com.oracle.truffle.sl.nodes.local.SLScopedNode

com.oracle.truffle.sl.nodes.SLStatementNode

com.oracle.truffle.sl.nodes.SLExpressionNode

com.oracle.truffle.sl.nodes.SLBinaryNode

com.oracle.truffle.sl.nodes.expression.SLAddNode

All Implemented Interfaces:

com.oracle.truffle.api.instrumentation.InstrumentableNode, com.oracle.truffle.api.nodes.NodeInterface, Cloneable

public abstract class SLAddNode
extends SLBinaryNode

SL node that performs the "+" operation, which performs addition on arbitrary precision numbers, as well as String concatenation if one of the operands is a String.

Type specialization on the input values is essential for the performance. This is achieved via node rewriting: specialized subclasses handle just a single type, so that the generic node that can handle all types is used only in cases where different types were encountered. The subclasses are automatically generated by the Truffle DSL. In addition, a factory class is generated that provides, e.g., node creation.

Nested Class Summary

Nested classes/interfaces inherited from class com.oracle.truffle.api.nodes.Node

com.oracle.truffle.api.nodes.Node.Child, com.oracle.truffle.api.nodes.Node.Children

Nested classes/interfaces inherited from interface com.oracle.truffle.api.instrumentation.InstrumentableNode

com.oracle.truffle.api.instrumentation.InstrumentableNode.WrapperNode

Constructor Summary

Constructors

Constructor and Description
SLAddNode()

Method Summary

Modifier and Type	Method and Description
protected long	add(long left, long right) Specialization for primitive long values.
protected com.oracle.truffle.api.strings.TruffleString	add(Object left, Object right, SLToTruffleStringNode toTruffleStringNodeLeft, SLToTruffleStringNode toTruffleStringNodeRight, com.oracle.truffle.api.strings.TruffleString.ConcatNode concatNode) Specialization for TruffleString concatenation.
protected SLBigNumber	add(SLBigNumber left, SLBigNumber right) This is the slow path of the arbitrary-precision arithmetic.
protected boolean	isString(Object a, Object b) Guard for TruffleString concatenation: returns true if either the left or the right operand is a TruffleString.
protected Object	typeError(Object left, Object right)

Methods inherited from class com.oracle.truffle.sl.nodes.SLExpressionNode

addExpressionTag, createWrapper, executeBoolean, executeGeneric, executeLong, executeVoid, hasTag

Methods inherited from class com.oracle.truffle.sl.nodes.SLStatementNode

addRootTag, addStatementTag, formatSourceSection, getSourceCharIndex, getSourceEndIndex, getSourceLength, getSourceSection, hasSource, isInstrumentable, setSourceSection, setUnavailableSourceSection, toString

Methods inherited from class com.oracle.truffle.sl.nodes.local.SLScopedNode

findBlock, getVisibleVariablesIndexOnEnter, hasScope, setVisibleVariablesIndexOnEnter, setVisibleVariablesIndexOnExit

Methods inherited from class com.oracle.truffle.api.nodes.Node

accept, adoptChildren, atomic, atomic, copy, deepCopy, getChildren, getCost, getDebugProperties, getDescription, getEncapsulatingSourceSection, getLock, getParent, getRootNode, insert, insert, isAdoptable, isSafelyReplaceableBy, notifyInserted, onReplace, replace, replace, reportPolymorphicSpecialize

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.oracle.truffle.api.instrumentation.InstrumentableNode

findInstrumentableParent, findNearestNodeAt, getNodeObject, materializeInstrumentableNodes

Constructor Detail

SLAddNode

public SLAddNode()

Method Detail

add

protected long add(long left,
                   long right)

Specialization for primitive long values. This is the fast path of the arbitrary-precision arithmetic. We need to check for overflows of the addition, and switch to the slow path. Therefore, we use an addition method that throws an exception on overflow. The rewriteOn attribute on the Specialization annotation automatically triggers the node rewriting on the exception.

In compiled code, addExact is compiled to efficient machine code that uses the processor's overflow flag. Therefore, this method is compiled to only two machine code instructions on the fast path.

This specialization is automatically selected by the Truffle DSL if both the left and right operand are long values.

add

protected SLBigNumber add(SLBigNumber left,
                          SLBigNumber right)

This is the slow path of the arbitrary-precision arithmetic. The SLBigNumber type of Java is doing everything we need.

This specialization is automatically selected by the Truffle DSL if both the left and right operand are SLBigNumber values. Because the type system defines an implicit conversion from long to SLBigNumber in SLTypes.castBigNumber(long), this specialization is also taken if the left or the right operand is a long value. Because the long specialization} has the rewriteOn attribute, this specialization is also taken if both input values are long values but the primitive addition overflows.

add

protected com.oracle.truffle.api.strings.TruffleString add(Object left,
                                                           Object right,
                                                           SLToTruffleStringNode toTruffleStringNodeLeft,
                                                           SLToTruffleStringNode toTruffleStringNodeRight,
                                                           com.oracle.truffle.api.strings.TruffleString.ConcatNode concatNode)

Specialization for TruffleString concatenation. The SL specification says that TruffleString concatenation works if either the left or the right operand is a TruffleString. The non-string operand is converted then automatically converted to a TruffleString.

To implement these semantics, we tell the Truffle DSL to use a custom guard. The guard function is defined in this class, but could also be in any superclass.

isString

protected boolean isString(Object a,
                           Object b)

Guard for TruffleString concatenation: returns true if either the left or the right operand is a TruffleString.

typeError

protected Object typeError(Object left,
                           Object right)