import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodHandles.Lookup;
+import java.lang.invoke.VarHandle;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Optional;
-import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import net.bytebuddy.ByteBuddy;
import net.bytebuddy.description.field.FieldDescription;
import net.bytebuddy.description.method.MethodDescription;
*
* <p>
* Code generation here is probably more involved than usual mainly due to the fact we *really* want to express the
- * strong connection between a generated class and BindingCodecContext in terms of a true constant, which boils down to
- * {@code private static final NodeContextSupplier NCS}. Having such constants provides significant boost to JITs
- * ability to optimize code -- especially with inlining and constant propagation.
+ * strong connection between a generated class to the extent possible. In most cases (grouping-generated types) this
+ * involves one level of indirection, which is a safe approach. If we are dealing with a type generated outside of a
+ * grouping statement, though, we are guaranteed instantiation-invariance and hence can hard-wire to a runtime-constant
+ * {@link NodeContextSupplier} -- which provides significant boost to JITs ability to optimize code -- especially with
+ * inlining and constant propagation.
*
* <p>
* The accessor mapping performance is critical due to users typically not taking care of storing the results acquired
* we end up generating a class with the following layout:
* <pre>
* public final class Foo$$$codecImpl extends CodecDataObject implements Foo {
- * private static final AtomicRefereceFieldUpdater<Foo$$$codecImpl, Object> getBar$$$A;
+ * private static final VarHandle getBar$$$V;
* private volatile Object getBar;
*
* public Foo$$$codecImpl(NormalizedNodeContainer data) {
* }
*
* public Bar getBar() {
- * return (Bar) codecMember(getBar$$$A, "bar");
+ * return (Bar) codecMember(getBar$$$V, "bar");
* }
* }
* </pre>
* single place in a maintainable form. The glue code is extremely light (~6 instructions), which is beneficial on both
* sides of invocation:
* - generated method can readily be inlined into the caller
- * - it forms a call site into which codeMember() can be inlined with AtomicReferenceFieldUpdater being constant
+ * - it forms a call site into which codeMember() can be inlined with VarHandle being constant
*
* <p>
- * The second point is important here, as it allows the invocation logic around AtomicRefereceFieldUpdater to completely
- * disappear, becoming synonymous with operations of a volatile field.
+ * The second point is important here, as it allows the invocation logic around VarHandle to completely disappear,
+ * becoming synonymous with operations on a field. Even though the field itself is declared as volatile, it is only ever
+ * accessed through helper method using VarHandles -- and those helpers are using relaxed field ordering
+ * of {@code getAcquire()}/{@code setRelease()} memory semantics.
*
* <p>
* Furthermore there are distinct {@code codecMember} methods, each of which supports a different invocation style:
*/
abstract class CodecDataObjectGenerator<T extends CodecDataObject<?>> implements ClassGenerator<T> {
// Not reusable definition: we can inline NodeContextSuppliers without a problem
+ // FIXME: 6.0.0: wire this implementation, which requires that BindingRuntimeTypes provides information about types
+ // being genenerated from within a grouping
private static final class Fixed<T extends CodecDataObject<?>> extends CodecDataObjectGenerator<T>
implements NodeContextSupplierProvider<T> {
private final ImmutableMap<Method, NodeContextSupplier> properties;
}
private abstract static class AbstractMethodImplementation implements Implementation {
- private static final Generic BB_ARFU = TypeDefinition.Sort.describe(AtomicReferenceFieldUpdater.class);
+ private static final Generic BB_HANDLE = TypeDefinition.Sort.describe(VarHandle.class);
private static final Generic BB_OBJECT = TypeDefinition.Sort.describe(Object.class);
private static final StackManipulation OBJECT_CLASS = ClassConstant.of(TypeDescription.OBJECT);
- private static final StackManipulation ARFU_NEWUPDATER = invokeMethod(AtomicReferenceFieldUpdater.class,
- "newUpdater", Class.class, Class.class, String.class);
+ private static final StackManipulation LOOKUP = invokeMethod(MethodHandles.class, "lookup");
+ private static final StackManipulation FIND_VAR_HANDLE = invokeMethod(Lookup.class,
+ "findVarHandle", Class.class, String.class, Class.class);
static final int PRIV_CONST = Opcodes.ACC_PRIVATE | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL
| Opcodes.ACC_SYNTHETIC;
final TypeDescription retType;
// getFoo
final String methodName;
- // getFoo$$$A
- final String arfuName;
+ // getFoo$$$V
+ final String handleName;
AbstractMethodImplementation(final String methodName, final TypeDescription retType) {
this.methodName = requireNonNull(methodName);
this.retType = requireNonNull(retType);
- this.arfuName = methodName + "$$$A";
+ this.handleName = methodName + "$$$V";
}
@Override
public InstrumentedType prepare(final InstrumentedType instrumentedType) {
final InstrumentedType tmp = instrumentedType
- // private static final AtomicReferenceFieldUpdater<This, Object> getFoo$$$A;
- .withField(new FieldDescription.Token(arfuName, PRIV_CONST, BB_ARFU))
+ // private static final VarHandle getFoo$$$V;
+ .withField(new FieldDescription.Token(handleName, PRIV_CONST, BB_HANDLE))
// private volatile Object getFoo;
.withField(new FieldDescription.Token(methodName, PRIV_VOLATILE, BB_OBJECT));
return tmp.withInitializer(new ByteCodeAppender.Simple(
- // getFoo$$$A = AtomicReferenceFieldUpdater.newUpdater(This.class, Object.class, "getFoo");
+ // TODO: acquiring lookup is expensive, we should share it across all initialization
+ // getFoo$$$V = MethodHandles.lookup().findVarHandle(This.class, "getFoo", Object.class);
+ LOOKUP,
ClassConstant.of(tmp),
- OBJECT_CLASS,
new TextConstant(methodName),
- ARFU_NEWUPDATER,
- putField(tmp, arfuName)));
+ OBJECT_CLASS,
+ FIND_VAR_HANDLE,
+ putField(tmp, handleName)));
}
}
private static final class KeyMethodImplementation extends AbstractMethodImplementation {
private static final StackManipulation CODEC_KEY = invokeMethod(CodecDataObject.class,
- "codecKey", AtomicReferenceFieldUpdater.class);
+ "codecKey", VarHandle.class);
KeyMethodImplementation(final String methodName, final TypeDescription retType) {
super(methodName, retType);
public ByteCodeAppender appender(final Target implementationTarget) {
final TypeDescription instrumentedType = implementationTarget.getInstrumentedType();
return new ByteCodeAppender.Simple(
- // return (FooType) codecKey(getFoo$$$A);
+ // return (FooType) codecKey(getFoo$$$V);
THIS,
- getField(instrumentedType, arfuName),
+ getField(instrumentedType, handleName),
CODEC_KEY,
TypeCasting.to(retType),
MethodReturn.REFERENCE);
*/
private static final class SimpleGetterMethodImplementation extends AbstractMethodImplementation {
private static final StackManipulation CODEC_MEMBER = invokeMethod(CodecDataObject.class,
- "codecMember", AtomicReferenceFieldUpdater.class, String.class);
+ "codecMember", VarHandle.class, String.class);
private static final StackManipulation BRIDGE_RESOLVE = invokeMethod(ClassGeneratorBridge.class,
"resolveLocalName", String.class);
private static final Generic BB_STRING = TypeDefinition.Sort.describe(String.class);
public ByteCodeAppender appender(final Target implementationTarget) {
final TypeDescription instrumentedType = implementationTarget.getInstrumentedType();
return new ByteCodeAppender.Simple(
- // return (FooType) codecMember(getFoo$$$A, getFoo$$$S);
+ // return (FooType) codecMember(getFoo$$$V, getFoo$$$S);
THIS,
- getField(instrumentedType, arfuName),
+ getField(instrumentedType, handleName),
getField(instrumentedType, stringName),
CODEC_MEMBER,
TypeCasting.to(retType),
private static final class StructuredGetterMethodImplementation extends AbstractMethodImplementation {
private static final StackManipulation CODEC_MEMBER = invokeMethod(CodecDataObject.class,
- "codecMember", AtomicReferenceFieldUpdater.class, Class.class);
+ "codecMember", VarHandle.class, Class.class);
private final Class<?> bindingClass;
public ByteCodeAppender appender(final Target implementationTarget) {
final TypeDescription instrumentedType = implementationTarget.getInstrumentedType();
return new ByteCodeAppender.Simple(
- // return (FooType) codecMember(getFoo$$$A, FooType.class);
+ // return (FooType) codecMember(getFoo$$$V, FooType.class);
THIS,
- getField(instrumentedType, arfuName),
+ getField(instrumentedType, handleName),
ClassConstant.of(TypeDefinition.Sort.describe(bindingClass).asErasure()),
CODEC_MEMBER,
TypeCasting.to(retType),
private static final class SupplierGetterMethodImplementation extends AbstractMethodImplementation {
private static final StackManipulation CODEC_MEMBER = invokeMethod(CodecDataObject.class,
- "codecMember", AtomicReferenceFieldUpdater.class, NodeContextSupplier.class);
+ "codecMember", VarHandle.class, NodeContextSupplier.class);
private static final StackManipulation BRIDGE_RESOLVE = invokeMethod(ClassGeneratorBridge.class,
"resolveNodeContextSupplier", String.class);
private static final Generic BB_NCS = TypeDefinition.Sort.describe(NodeContextSupplier.class);
public ByteCodeAppender appender(final Target implementationTarget) {
final TypeDescription instrumentedType = implementationTarget.getInstrumentedType();
return new ByteCodeAppender.Simple(
- // return (FooType) codecMember(getFoo$$$A, getFoo$$$C);
+ // return (FooType) codecMember(getFoo$$$V, getFoo$$$C);
THIS,
- getField(instrumentedType, arfuName),
+ getField(instrumentedType, handleName),
getField(instrumentedType, contextName),
CODEC_MEMBER,
TypeCasting.to(retType),
Code Review / mdsal.git / blobdiff