// Constructors and factory methods in this class *must* be package scoped or private. private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) { super(mtype, form); if (!member.isResolved()) throw new InternalError(); if (member.getDeclaringClass().isInterface() && member.isMethod() && !member.isAbstract()) { // Check for corner case: invokeinterface of Object method MemberName m = new MemberName( Object.class, member.getName(), member.getMethodType(), member.getReferenceKind()); m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null); if (m != null && m.isPublic()) { assert (member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong member = m; } } this.member = member; }
/** * The flavor of method handle which implements a constant reference to a class member. * * @author jrose */ class DirectMethodHandle extends MethodHandle { final MemberName member; // Constructors and factory methods in this class *must* be package scoped or private. private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) { super(mtype, form); if (!member.isResolved()) throw new InternalError(); if (member.getDeclaringClass().isInterface() && member.isMethod() && !member.isAbstract()) { // Check for corner case: invokeinterface of Object method MemberName m = new MemberName( Object.class, member.getName(), member.getMethodType(), member.getReferenceKind()); m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null); if (m != null && m.isPublic()) { assert (member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong member = m; } } this.member = member; } // Factory methods: static DirectMethodHandle make(byte refKind, Class<?> receiver, MemberName member) { MethodType mtype = member.getMethodOrFieldType(); if (!member.isStatic()) { if (!member.getDeclaringClass().isAssignableFrom(receiver) || member.isConstructor()) throw new InternalError(member.toString()); mtype = mtype.insertParameterTypes(0, receiver); } if (!member.isField()) { if (refKind == REF_invokeSpecial) { member = member.asSpecial(); LambdaForm lform = preparedLambdaForm(member); return new Special(mtype, lform, member); } else { LambdaForm lform = preparedLambdaForm(member); return new DirectMethodHandle(mtype, lform, member); } } else { LambdaForm lform = preparedFieldLambdaForm(member); if (member.isStatic()) { long offset = MethodHandleNatives.staticFieldOffset(member); Object base = MethodHandleNatives.staticFieldBase(member); return new StaticAccessor(mtype, lform, member, base, offset); } else { long offset = MethodHandleNatives.objectFieldOffset(member); assert (offset == (int) offset); return new Accessor(mtype, lform, member, (int) offset); } } } static DirectMethodHandle make(Class<?> receiver, MemberName member) { byte refKind = member.getReferenceKind(); if (refKind == REF_invokeSpecial) refKind = REF_invokeVirtual; return make(refKind, receiver, member); } static DirectMethodHandle make(MemberName member) { if (member.isConstructor()) return makeAllocator(member); return make(member.getDeclaringClass(), member); } private static DirectMethodHandle makeAllocator(MemberName ctor) { assert (ctor.isConstructor() && ctor.getName().equals("<init>")); Class<?> instanceClass = ctor.getDeclaringClass(); ctor = ctor.asConstructor(); assert (ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor; MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass); LambdaForm lform = preparedLambdaForm(ctor); MemberName init = ctor.asSpecial(); assert (init.getMethodType().returnType() == void.class); return new Constructor(mtype, lform, ctor, init, instanceClass); } @Override BoundMethodHandle rebind() { return BoundMethodHandle.makeReinvoker(this); } @Override MethodHandle copyWith(MethodType mt, LambdaForm lf) { assert (this.getClass() == DirectMethodHandle.class); // must override in subclasses return new DirectMethodHandle(mt, lf, member); } @Override String internalProperties() { return "\n& DMH.MN=" + internalMemberName(); } //// Implementation methods. @Override @ForceInline MemberName internalMemberName() { return member; } private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory(); /** * Create a LF which can invoke the given method. Cache and share this structure among all methods * with the same basicType and refKind. */ private static LambdaForm preparedLambdaForm(MemberName m) { assert (m.isInvocable()) : m; // call preparedFieldLambdaForm instead MethodType mtype = m.getInvocationType().basicType(); assert (!m.isMethodHandleInvoke()) : m; int which; switch (m.getReferenceKind()) { case REF_invokeVirtual: which = LF_INVVIRTUAL; break; case REF_invokeStatic: which = LF_INVSTATIC; break; case REF_invokeSpecial: which = LF_INVSPECIAL; break; case REF_invokeInterface: which = LF_INVINTERFACE; break; case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break; default: throw new InternalError(m.toString()); } if (which == LF_INVSTATIC && shouldBeInitialized(m)) { // precompute the barrier-free version: preparedLambdaForm(mtype, which); which = LF_INVSTATIC_INIT; } LambdaForm lform = preparedLambdaForm(mtype, which); maybeCompile(lform, m); assert (lform.methodType().dropParameterTypes(0, 1).equals(m.getInvocationType().basicType())) : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); return lform; } private static LambdaForm preparedLambdaForm(MethodType mtype, int which) { LambdaForm lform = mtype.form().cachedLambdaForm(which); if (lform != null) return lform; lform = makePreparedLambdaForm(mtype, which); return mtype.form().setCachedLambdaForm(which, lform); } static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) { boolean needsInit = (which == LF_INVSTATIC_INIT); boolean doesAlloc = (which == LF_NEWINVSPECIAL); String linkerName; LambdaForm.Kind kind; switch (which) { case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break; case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break; case LF_INVSTATIC_INIT: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break; case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break; case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break; case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break; default: throw new InternalError("which=" + which); } MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class); if (doesAlloc) mtypeWithArg = mtypeWithArg .insertParameterTypes(0, Object.class) // insert newly allocated obj .changeReturnType(void.class); // <init> returns void MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic); try { linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class); } catch (ReflectiveOperationException ex) { throw newInternalError(ex); } final int DMH_THIS = 0; final int ARG_BASE = 1; final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); int nameCursor = ARG_LIMIT; final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1); final int GET_MEMBER = nameCursor++; final int LINKER_CALL = nameCursor++; Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); assert (names.length == nameCursor); if (doesAlloc) { // names = { argx,y,z,... new C, init method } names[NEW_OBJ] = new Name(NF_allocateInstance, names[DMH_THIS]); names[GET_MEMBER] = new Name(NF_constructorMethod, names[DMH_THIS]); } else if (needsInit) { names[GET_MEMBER] = new Name(NF_internalMemberNameEnsureInit, names[DMH_THIS]); } else { names[GET_MEMBER] = new Name(NF_internalMemberName, names[DMH_THIS]); } assert (findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]); Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER + 1, Object[].class); assert (outArgs[outArgs.length - 1] == names[GET_MEMBER]); // look, shifted args! int result = LAST_RESULT; if (doesAlloc) { assert (outArgs[outArgs.length - 2] == names[NEW_OBJ]); // got to move this one System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length - 2); outArgs[0] = names[NEW_OBJ]; result = NEW_OBJ; } names[LINKER_CALL] = new Name(linker, outArgs); String lambdaName = kind.defaultLambdaName + "_" + shortenSignature(basicTypeSignature(mtype)); LambdaForm lform = new LambdaForm(lambdaName, ARG_LIMIT, names, result, kind); // This is a tricky bit of code. Don't send it through the LF interpreter. lform.compileToBytecode(); return lform; } static Object findDirectMethodHandle(Name name) { if (name.function == NF_internalMemberName || name.function == NF_internalMemberNameEnsureInit || name.function == NF_constructorMethod) { assert (name.arguments.length == 1); return name.arguments[0]; } return null; } private static void maybeCompile(LambdaForm lform, MemberName m) { if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class)) // Help along bootstrapping... lform.compileToBytecode(); } /** Static wrapper for DirectMethodHandle.internalMemberName. */ @ForceInline /*non-public*/ static Object internalMemberName(Object mh) { return ((DirectMethodHandle) mh).member; } /** * Static wrapper for DirectMethodHandle.internalMemberName. This one also forces initialization. */ /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) { DirectMethodHandle dmh = (DirectMethodHandle) mh; dmh.ensureInitialized(); return dmh.member; } /*non-public*/ static boolean shouldBeInitialized(MemberName member) { switch (member.getReferenceKind()) { case REF_invokeStatic: case REF_getStatic: case REF_putStatic: case REF_newInvokeSpecial: break; default: // No need to initialize the class on this kind of member. return false; } Class<?> cls = member.getDeclaringClass(); if (cls == ValueConversions.class || cls == MethodHandleImpl.class || cls == Invokers.class) { // These guys have lots of <clinit> DMH creation but we know // the MHs will not be used until the system is booted. return false; } if (VerifyAccess.isSamePackage(MethodHandle.class, cls) || VerifyAccess.isSamePackage(ValueConversions.class, cls)) { // It is a system class. It is probably in the process of // being initialized, but we will help it along just to be safe. if (UNSAFE.shouldBeInitialized(cls)) { UNSAFE.ensureClassInitialized(cls); } return false; } return UNSAFE.shouldBeInitialized(cls); } private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> { @Override protected WeakReference<Thread> computeValue(Class<?> type) { UNSAFE.ensureClassInitialized(type); if (UNSAFE.shouldBeInitialized(type)) // If the previous call didn't block, this can happen. // We are executing inside <clinit>. return new WeakReference<>(Thread.currentThread()); return null; } static final EnsureInitialized INSTANCE = new EnsureInitialized(); } private void ensureInitialized() { if (checkInitialized(member)) { // The coast is clear. Delete the <clinit> barrier. if (member.isField()) updateForm(preparedFieldLambdaForm(member)); else updateForm(preparedLambdaForm(member)); } } private static boolean checkInitialized(MemberName member) { Class<?> defc = member.getDeclaringClass(); WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc); if (ref == null) { return true; // the final state } Thread clinitThread = ref.get(); // Somebody may still be running defc.<clinit>. if (clinitThread == Thread.currentThread()) { // If anybody is running defc.<clinit>, it is this thread. if (UNSAFE.shouldBeInitialized(defc)) // Yes, we are running it; keep the barrier for now. return false; } else { // We are in a random thread. Block. UNSAFE.ensureClassInitialized(defc); } assert (!UNSAFE.shouldBeInitialized(defc)); // put it into the final state EnsureInitialized.INSTANCE.remove(defc); return true; } /*non-public*/ static void ensureInitialized(Object mh) { ((DirectMethodHandle) mh).ensureInitialized(); } /** This subclass represents invokespecial instructions. */ static class Special extends DirectMethodHandle { private Special(MethodType mtype, LambdaForm form, MemberName member) { super(mtype, form, member); } @Override boolean isInvokeSpecial() { return true; } @Override MethodHandle copyWith(MethodType mt, LambdaForm lf) { return new Special(mt, lf, member); } } /** This subclass handles constructor references. */ static class Constructor extends DirectMethodHandle { final MemberName initMethod; final Class<?> instanceClass; private Constructor( MethodType mtype, LambdaForm form, MemberName constructor, MemberName initMethod, Class<?> instanceClass) { super(mtype, form, constructor); this.initMethod = initMethod; this.instanceClass = instanceClass; assert (initMethod.isResolved()); } @Override MethodHandle copyWith(MethodType mt, LambdaForm lf) { return new Constructor(mt, lf, member, initMethod, instanceClass); } } /*non-public*/ static Object constructorMethod(Object mh) { Constructor dmh = (Constructor) mh; return dmh.initMethod; } /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException { Constructor dmh = (Constructor) mh; return UNSAFE.allocateInstance(dmh.instanceClass); } /** This subclass handles non-static field references. */ static class Accessor extends DirectMethodHandle { final Class<?> fieldType; final int fieldOffset; private Accessor(MethodType mtype, LambdaForm form, MemberName member, int fieldOffset) { super(mtype, form, member); this.fieldType = member.getFieldType(); this.fieldOffset = fieldOffset; } @Override Object checkCast(Object obj) { return fieldType.cast(obj); } @Override MethodHandle copyWith(MethodType mt, LambdaForm lf) { return new Accessor(mt, lf, member, fieldOffset); } } @ForceInline /*non-public*/ static long fieldOffset(Object accessorObj) { // Note: We return a long because that is what Unsafe.getObject likes. // We store a plain int because it is more compact. return ((Accessor) accessorObj).fieldOffset; } @ForceInline /*non-public*/ static Object checkBase(Object obj) { // Note that the object's class has already been verified, // since the parameter type of the Accessor method handle // is either member.getDeclaringClass or a subclass. // This was verified in DirectMethodHandle.make. // Therefore, the only remaining check is for null. // Since this check is *not* guaranteed by Unsafe.getInt // and its siblings, we need to make an explicit one here. return Objects.requireNonNull(obj); } /** This subclass handles static field references. */ static class StaticAccessor extends DirectMethodHandle { private final Class<?> fieldType; private final Object staticBase; private final long staticOffset; private StaticAccessor( MethodType mtype, LambdaForm form, MemberName member, Object staticBase, long staticOffset) { super(mtype, form, member); this.fieldType = member.getFieldType(); this.staticBase = staticBase; this.staticOffset = staticOffset; } @Override Object checkCast(Object obj) { return fieldType.cast(obj); } @Override MethodHandle copyWith(MethodType mt, LambdaForm lf) { return new StaticAccessor(mt, lf, member, staticBase, staticOffset); } } @ForceInline /*non-public*/ static Object nullCheck(Object obj) { return Objects.requireNonNull(obj); } @ForceInline /*non-public*/ static Object staticBase(Object accessorObj) { return ((StaticAccessor) accessorObj).staticBase; } @ForceInline /*non-public*/ static long staticOffset(Object accessorObj) { return ((StaticAccessor) accessorObj).staticOffset; } @ForceInline /*non-public*/ static Object checkCast(Object mh, Object obj) { return ((DirectMethodHandle) mh).checkCast(obj); } Object checkCast(Object obj) { return member.getReturnType().cast(obj); } // Caching machinery for field accessors: private static final byte AF_GETFIELD = 0, AF_PUTFIELD = 1, AF_GETSTATIC = 2, AF_PUTSTATIC = 3, AF_GETSTATIC_INIT = 4, AF_PUTSTATIC_INIT = 5, AF_LIMIT = 6; // Enumerate the different field kinds using Wrapper, // with an extra case added for checked references. private static final int FT_LAST_WRAPPER = Wrapper.COUNT - 1, FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(), FT_CHECKED_REF = FT_LAST_WRAPPER + 1, FT_LIMIT = FT_LAST_WRAPPER + 2; private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) { return ((formOp * FT_LIMIT * 2) + (isVolatile ? FT_LIMIT : 0) + ftypeKind); } @Stable private static final LambdaForm[] ACCESSOR_FORMS = new LambdaForm[afIndex(AF_LIMIT, false, 0)]; private static int ftypeKind(Class<?> ftype) { if (ftype.isPrimitive()) return Wrapper.forPrimitiveType(ftype).ordinal(); else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) return FT_UNCHECKED_REF; else return FT_CHECKED_REF; } /** * Create a LF which can access the given field. Cache and share this structure among all fields * with the same basicType and refKind. */ private static LambdaForm preparedFieldLambdaForm(MemberName m) { Class<?> ftype = m.getFieldType(); boolean isVolatile = m.isVolatile(); byte formOp; switch (m.getReferenceKind()) { case REF_getField: formOp = AF_GETFIELD; break; case REF_putField: formOp = AF_PUTFIELD; break; case REF_getStatic: formOp = AF_GETSTATIC; break; case REF_putStatic: formOp = AF_PUTSTATIC; break; default: throw new InternalError(m.toString()); } if (shouldBeInitialized(m)) { // precompute the barrier-free version: preparedFieldLambdaForm(formOp, isVolatile, ftype); assert ((AF_GETSTATIC_INIT - AF_GETSTATIC) == (AF_PUTSTATIC_INIT - AF_PUTSTATIC)); formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC); } LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype); maybeCompile(lform, m); assert (lform.methodType().dropParameterTypes(0, 1).equals(m.getInvocationType().basicType())) : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); return lform; } private static LambdaForm preparedFieldLambdaForm( byte formOp, boolean isVolatile, Class<?> ftype) { int ftypeKind = ftypeKind(ftype); int afIndex = afIndex(formOp, isVolatile, ftypeKind); LambdaForm lform = ACCESSOR_FORMS[afIndex]; if (lform != null) return lform; lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind); ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS return lform; } private static final Wrapper[] ALL_WRAPPERS = Wrapper.values(); private static LambdaForm makePreparedFieldLambdaForm( byte formOp, boolean isVolatile, int ftypeKind) { boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1); boolean isStatic = (formOp >= AF_GETSTATIC); boolean needsInit = (formOp >= AF_GETSTATIC_INIT); boolean needsCast = (ftypeKind == FT_CHECKED_REF); Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]); Class<?> ft = fw.primitiveType(); assert (ftypeKind(needsCast ? String.class : ft) == ftypeKind); // getObject, putIntVolatile, etc. StringBuilder nameBuilder = new StringBuilder(); if (isGetter) { nameBuilder.append("get"); } else { nameBuilder.append("put"); } nameBuilder.append(fw.primitiveSimpleName()); nameBuilder.setCharAt(3, Character.toUpperCase(nameBuilder.charAt(3))); if (isVolatile) { nameBuilder.append("Volatile"); } MethodType linkerType; if (isGetter) linkerType = MethodType.methodType(ft, Object.class, long.class); else linkerType = MethodType.methodType(void.class, Object.class, long.class, ft); MemberName linker = new MemberName(Unsafe.class, nameBuilder.toString(), linkerType, REF_invokeVirtual); try { linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class); } catch (ReflectiveOperationException ex) { throw newInternalError(ex); } // What is the external type of the lambda form? MethodType mtype; if (isGetter) mtype = MethodType.methodType(ft); else mtype = MethodType.methodType(void.class, ft); mtype = mtype.basicType(); // erase short to int, etc. if (!isStatic) mtype = mtype.insertParameterTypes(0, Object.class); final int DMH_THIS = 0; final int ARG_BASE = 1; final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); // if this is for non-static access, the base pointer is stored at this index: final int OBJ_BASE = isStatic ? -1 : ARG_BASE; // if this is for write access, the value to be written is stored at this index: final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1; int nameCursor = ARG_LIMIT; final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any final int F_OFFSET = nameCursor++; // Either static offset or field offset. final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1); final int INIT_BAR = (needsInit ? nameCursor++ : -1); final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1); final int LINKER_CALL = nameCursor++; final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1); final int RESULT = nameCursor - 1; // either the call or the cast Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); if (needsInit) names[INIT_BAR] = new Name(NF_ensureInitialized, names[DMH_THIS]); if (needsCast && !isGetter) names[PRE_CAST] = new Name(NF_checkCast, names[DMH_THIS], names[SET_VALUE]); Object[] outArgs = new Object[1 + linkerType.parameterCount()]; assert (outArgs.length == (isGetter ? 3 : 4)); outArgs[0] = UNSAFE; if (isStatic) { outArgs[1] = names[F_HOLDER] = new Name(NF_staticBase, names[DMH_THIS]); outArgs[2] = names[F_OFFSET] = new Name(NF_staticOffset, names[DMH_THIS]); } else { outArgs[1] = names[OBJ_CHECK] = new Name(NF_checkBase, names[OBJ_BASE]); outArgs[2] = names[F_OFFSET] = new Name(NF_fieldOffset, names[DMH_THIS]); } if (!isGetter) { outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]); } for (Object a : outArgs) assert (a != null); names[LINKER_CALL] = new Name(linker, outArgs); if (needsCast && isGetter) names[POST_CAST] = new Name(NF_checkCast, names[DMH_THIS], names[LINKER_CALL]); for (Name n : names) assert (n != null); // add some detail to the lambdaForm debugname, // significant only for debugging if (isStatic) { nameBuilder.append("Static"); } else { nameBuilder.append("Field"); } if (needsCast) nameBuilder.append("Cast"); if (needsInit) nameBuilder.append("Init"); return new LambdaForm(nameBuilder.toString(), ARG_LIMIT, names, RESULT); } /** * Pre-initialized NamedFunctions for bootstrapping purposes. Factored in an inner class to delay * initialization until first usage. */ static final NamedFunction NF_internalMemberName, NF_internalMemberNameEnsureInit, NF_ensureInitialized, NF_fieldOffset, NF_checkBase, NF_staticBase, NF_staticOffset, NF_checkCast, NF_allocateInstance, NF_constructorMethod; static { try { NamedFunction nfs[] = { NF_internalMemberName = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("internalMemberName", Object.class)), NF_internalMemberNameEnsureInit = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod( "internalMemberNameEnsureInit", Object.class)), NF_ensureInitialized = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("ensureInitialized", Object.class)), NF_fieldOffset = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("fieldOffset", Object.class)), NF_checkBase = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("checkBase", Object.class)), NF_staticBase = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("staticBase", Object.class)), NF_staticOffset = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("staticOffset", Object.class)), NF_checkCast = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod( "checkCast", Object.class, Object.class)), NF_allocateInstance = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("allocateInstance", Object.class)), NF_constructorMethod = new NamedFunction( DirectMethodHandle.class.getDeclaredMethod("constructorMethod", Object.class)) }; // Each nf must be statically invocable or we get tied up in our bootstraps. assert (InvokerBytecodeGenerator.isStaticallyInvocable(nfs)); } catch (ReflectiveOperationException ex) { throw newInternalError(ex); } } static { // The Holder class will contain pre-generated DirectMethodHandles resolved // speculatively using MemberName.getFactory().resolveOrNull. However, that // doesn't initialize the class, which subtly breaks inlining etc. By forcing // initialization of the Holder class we avoid these issues. UNSAFE.ensureClassInitialized(Holder.class); } /* Placeholder class for DirectMethodHandles generated ahead of time */ final class Holder {} }