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Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* The Universal Permissive License (UPL), Version 1.0
*
* Subject to the condition set forth below, permission is hereby granted to any
* person obtaining a copy of this software, associated documentation and/or
* data (collectively the "Software"), free of charge and under any and all
* copyright rights in the Software, and any and all patent rights owned or
* freely licensable by each licensor hereunder covering either (i) the
* unmodified Software as contributed to or provided by such licensor, or (ii)
* the Larger Works (as defined below), to deal in both
*
* (a) the Software, and
*
* (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
* one is included with the Software each a "Larger Work" to which the Software
* is contributed by such licensors),
*
* without restriction, including without limitation the rights to copy, create
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* Software and the Larger Work(s), and to sublicense the foregoing rights on
* either these or other terms.
*
* This license is subject to the following condition:
*
* The above copyright notice and either this complete permission notice or at a
* minimum a reference to the UPL must be included in all copies or substantial
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package com.oracle.truffle.api.library;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Specialization;
/**
* The cached library annotation allows to use {@link com.oracle.truffle.api.library Truffle
* Libraries} conveniently in {@link Specialization specializations} or {@link ExportMessage
* exported messages}. It is designed as the primary way of using libraries. The
* {@link CachedLibrary} annotation may be used for any parameters of methods annotated with
* {@linkplain Specialization @Specialization} or {@linkplain ExportMessage @ExportMessage}.
*
* Using Specialized Libraries
*
* A cached library can be specialized for a value that is referred to with the {@link #value()
* value expression} attribute. A specialized library implicitly prepends a guard for the
* {@link Library#accepts(Object) acceptance} of a library with the provided value expression.
* Adding the acceptance guard leads to multiple specialization instances as it binds to the cached
* library value. The {@link Specialization#limit() specialization} or {@link ExportMessage#limit()
* export} limit attribute must therefore be specified. If this limit overflows then the operation
* will rewrite itself to an {@link LibraryFactory#getUncached(Object) uncached} version of the
* library. Multiple specialized libraries may be used per export or specialization. The acceptance
* guards for these libraries will be added in the order of their declaration.
*
*
Usage:
*
*
* @NodeChild
* @NodeChild
* abstract static class ArrayReadNode extends ExpressionNode {
* @Specialization(guards = "arrays.isArray(array)", limit = "2")
* int doDefault(Object array, int index,
* @CachedLibrary("array") ArrayLibrary arrays) {
* return arrays.read(array, index);
* }
* }
*
*
*
* It is recommended to use the plural of the specialized parameter name as naming convention for
* the library parameter name, e.g. a library for an array value is called
* arrays. If multiple libraries are specialized for the same specialized expression it
* is recommended to prepend the library name e.g. interopArrays.
*
*
Using Dispatched Libraries
*
* If no specialized value expression can be specified, i.e. if the value is computed as part of the
* operation, then a dispatched version of a library can be used by omitting the {@link #value()
* value} attribute and specifying the {@link #limit()} attribute instead. A dispatched library
* builds the specialized value inline cache internally for each invocation of a message instead of
* once per outer specialization or export. An instance of a dispatched library therefore
* {@link Library#accepts(Object) accepts} any value as receiver. It is recommended to use the same
* generic library instance for few message invocations of similar values only, could lead to
* duplication of inline cache dispatches in the compiled code. The limit of a dispatched library
* may be set to 0 to directly switch to an uncached version of a library.
*
*
*
Usage:
*
* The following example combines the use of specialized and dispatched libraries. In this example
* the array is read twice. For the first outer read the specializing expression can be used.
* For the second read the specializing expression cannot be used as it depends on the result of the
* outer read. We therefore use a dispatched library for the inner array.
*
*
* @NodeChild
* @NodeChild
* @NodeChild
* abstract static class TwoDimReadNode extends ExpressionNode {
* @Specialization(guards = "outerArrays.isArray(array)", limit = "2")
* int doDefault(Object array, int outerIndex, int innerIndex,
* @CachedLibrary("array") ArrayLibrary outerArrays,
* @CachedLibrary(limit = "2") ArrayLibrary innerArrays) {
* return innerArrays.read(outerArrays.read(outerIndex), innerIndex);
* }
* }
*
*
* @see LibraryFactory for manually instantiating libraries
* @see com.oracle.truffle.api.library Truffle Library reference documentation
* @since 19.0
*/
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.PARAMETER})
public @interface CachedLibrary {
/**
* Sets the specialized value expression when using specialized libraries. The same syntax
* applies as for {@link Cached} value expressions.
*
* @see CachedLibrary for usage examples.
* @since 19.0
*/
String value() default "";
/**
* Sets the limit expression when using dispatched libraries. The limit expression sets the
* number of internally dispatched specialized libraries until an
* {@link LibraryFactory#getUncached() uncached} version of the library will be used.
*
* @see CachedLibrary for usage examples.
* @since 19.0
*/
String limit() default "";
}