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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package org.graalvm.compiler.api.replacements;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Array;
import jdk.vm.ci.meta.Signature;
Denotes a method whose body is used by a compiler as the substitute (or intrinsification) of another method. The exact mechanism used to do the substitution is compiler dependent but every compiler should require substitute methods to be annotated with MethodSubstitution. In addition, a compiler is recommended to implement MethodSubstitutionRegistry to advertise the mechanism by which it supports registration of method substitutes. A compiler may support partial intrinsification where only a part of a method is implemented by the compiler. The unsupported path is expressed by a call to either the original or substitute method from within the substitute method. Such as call is a partial intrinsic exit. For example, here's a HotSpot specific intrinsic for Array.newInstance(Class<?>, int) that only handles the case where the VM representation of the array class to be instantiated already exists: @MethodSubstitution
public static Object newInstance(Class componentType, int length) {
if (componentType == null || loadKlassFromObject(componentType, arrayKlassOffset(INJECTED_VMCONFIG), CLASS_ARRAY_KLASS_LOCATION).isNull()) {
// Array class not yet created - exit the intrinsic and call the original method
return newInstance(componentType, length);
}
return DynamicNewArrayNode.newArray(GraalDirectives.guardingNonNull(componentType), length, JavaKind.Object);
}
Here's the same intrinsification where the exit is expressed as a call to the original method:
@MethodSubstitution
public static Object newInstance(Class componentType, int length) {
if (componentType == null || loadKlassFromObject(componentType, arrayKlassOffset(INJECTED_VMCONFIG), CLASS_ARRAY_KLASS_LOCATION).isNull()) {
// Array class not yet created - exit the intrinsic and call the original method
return java.lang.reflect.newInstance(componentType, length);
}
return DynamicNewArrayNode.newArray(GraalDirectives.guardingNonNull(componentType), length, JavaKind.Object);
}
A condition for a partial intrinsic exit is that it is uses the unmodified parameters of the
substitute as arguments to the partial intrinsic exit call. There must also be no side effecting
instruction between the start of the substitute method and the partial intrinsic exit.
/**
* Denotes a method whose body is used by a compiler as the substitute (or intrinsification) of
* another method. The exact mechanism used to do the substitution is compiler dependent but every
* compiler should require substitute methods to be annotated with {@link MethodSubstitution}. In
* addition, a compiler is recommended to implement {@link MethodSubstitutionRegistry} to advertise
* the mechanism by which it supports registration of method substitutes.
*
* A compiler may support partial intrinsification where only a part of a method is implemented by
* the compiler. The unsupported path is expressed by a call to either the original or substitute
* method from within the substitute method. Such as call is a <i>partial intrinsic exit</i>.
*
* For example, here's a HotSpot specific intrinsic for {@link Array#newInstance(Class, int)} that
* only handles the case where the VM representation of the array class to be instantiated already
* exists:
*
* <pre>
* @MethodSubstitution
* public static Object newInstance(Class<?> componentType, int length) {
* if (componentType == null || loadKlassFromObject(componentType, arrayKlassOffset(INJECTED_VMCONFIG), CLASS_ARRAY_KLASS_LOCATION).isNull()) {
* // Array class not yet created - exit the intrinsic and call the original method
* return newInstance(componentType, length);
* }
* return DynamicNewArrayNode.newArray(GraalDirectives.guardingNonNull(componentType), length, JavaKind.Object);
* }
* </pre>
*
* Here's the same intrinsification where the exit is expressed as a call to the original method:
*
* <pre>
* @MethodSubstitution
* public static Object newInstance(Class<?> componentType, int length) {
* if (componentType == null || loadKlassFromObject(componentType, arrayKlassOffset(INJECTED_VMCONFIG), CLASS_ARRAY_KLASS_LOCATION).isNull()) {
* // Array class not yet created - exit the intrinsic and call the original method
* return java.lang.reflect.newInstance(componentType, length);
* }
* return DynamicNewArrayNode.newArray(GraalDirectives.guardingNonNull(componentType), length, JavaKind.Object);
* }
* </pre>
*
* A condition for a partial intrinsic exit is that it is uses the unmodified parameters of the
* substitute as arguments to the partial intrinsic exit call. There must also be no side effecting
* instruction between the start of the substitute method and the partial intrinsic exit.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MethodSubstitution {
Gets the name of the original method.
If the default value is specified for this element, then the name of the original method is
same as the substitute method.
/**
* Gets the name of the original method.
* <p>
* If the default value is specified for this element, then the name of the original method is
* same as the substitute method.
*/
String value() default "";
Determines if the original method is static.
/**
* Determines if the original method is static.
*/
boolean isStatic() default true;
Gets the signature of the original method.
If the default value is specified for this element, then the signature of the original method
is the same as the substitute method.
/**
* Gets the {@linkplain Signature#toMethodDescriptor signature} of the original method.
* <p>
* If the default value is specified for this element, then the signature of the original method
* is the same as the substitute method.
*/
String signature() default "";
Determines if the substitution is for a method that may not be part of the runtime. For
example, a method introduced in a later JDK version. Substitutions for such methods are
omitted if the original method cannot be found.
/**
* Determines if the substitution is for a method that may not be part of the runtime. For
* example, a method introduced in a later JDK version. Substitutions for such methods are
* omitted if the original method cannot be found.
*/
boolean optional() default false;
}